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S0021967320309742
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A hexafluroisopropanol alkanol supramolecular solvent based magnetic solvent bar liquid phase microextraction method was proposed for extraction of non steroidal anti inflammatory drugs in human serum . The restricted access HFIP alkanol SUPRAS was prepared by injecting a mixture of HFIP and alkanol into water . A stainless steel needle was inserted into a piece of hollow fiber to prepare a magnetic bar . Then the magnetic bar was dipped in SUPRAS to impregnate the wall pores of the hollow fiber followed by placing it into the serum sample for extraction . Only 4 L of SUPRAS was consumed per bar . The MSB not only functioned for stirring but also played the role of extraction and magnetic separation . Under the optimal extraction conditions which was obtained by one variable at a time and response surface methodology the novel MSB LPME was coupled with high performance liquid chromatography tandem mass spectrometry to determine NSAIDs in human serum . The method showed a good linear relationship . Method limits of detection and method limits of quantitation were in the range of 0.25 0.95 g L
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A supramolecular solvent based magnetic solvent bar LPME method was proposed. The magnetic solvent bar functioned as the stirrer for extraction and separation. High density supramolecular solvent and magnetic needle avoid solvent bar floating. The method was used for NSAIDs analysis in human serum with no need for protein deposition. Restricted access supramolecular solvent and hollow fiber reduced matrix effect.
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S0021967320309778
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The internal energy distributions of thermometer ions dissolved in supercritical and liquid solvents and produced in the gas phase by electrospray were measured and compared by the survival yield method . The influence of different chromatographic conditions such as the nature of solvents the composition of the mobile phase the pressure of the back pressure regulator was studied for supercritical fluid chromatography whereas the influence of the composition and of the flow rate of the mobile phase was investigated for liquid chromatography . The MS instrumental parameters were studied in parallel for SFC and LC showing that the drying gas temperature and the fragmentor voltage affected the internal energy distribution whereas the capillary voltage did not modify the internal energy distribution . A comparison of the internal energy distributions generated by SFC and LC was carried out leading to conclude that SFC led to higher internal energy
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Influence of chromatographic parameters on the internal energy distribution. MS instrumental parameters were studied in parallel for SFC and LC. SFC ESI MS led to higher internal energies for thermometer ions than LC ESI MS.
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S0021967320309894
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A compound specific chlorine bromine isotope analysis method was developed using gas chromatography quadrupole mass spectrometry for polychlorinated biphenyls and polybrominated diphenyl ethers which are toxic to human health and are frequently detected in various abiotic and biotic media . For PCB congeners the molecular ion method for a concentration of 0.510.0 ppm a dwell time of 20100 ms a relative EM voltage of 200 V an electric current of 34 A and an ionization energy of 70 eV was determined as the most suitable scheme which obtained standard deviations of chlorine isotope ratios ranging from 0.00008 to 0.00068 . As for the PBDE congeners the lowest SDs ranging from 0.00050 to 0.00172 were determined using the top four ion method with a concentration of 510 ppm and a dwell time of 2050 ms . Both the chlorine and bromine isotope ratios showed strong concentration dependencies . Therefore external standardization or detecting chlorine and bromine isotope ratios at a uniform concentration level is necessary to eliminate the concentration effect . In addition
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A Cl Br CSIA method using GC qMS was developed for PCBs and PBDEs. The best schemes were the molecular ion PCB and top four ion PBDE methods. Both chlorine and bromine isotope ratios showed strong concentration dependencies. Cl Br CSIA provides a new way to trace the sources and degradation of PCBs PBDEs.
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S002199241730182X
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This study investigated differences between healthy bilingual participants and bilingual participants with traumatic brain injury on verbal fluency tasks . The performance of three Spanish English bilingual speakers with traumatic brain injury was compared to the performance of 30 neurotypical bilingual speakers on tasks of category and letter verbal fluency in English and Spanish . Responses were analyzed for total number of correct productions differences in correct productions between languages average cluster size total number of switches and rates of language choice errors . The data were analyzed using predicted scores from regression equations based on neurotypical data and modified t tests . Analyses revealed significantly lower total output than predicted by the regression equations for both task types and in both languages for one TBI participant . The same participant demonstrated significantly lower total number of switches than the neurotypical group . Two participants demonstrated higher rates of language choice errors than the neurotypical group . There were no significant differences between TBI participants and the neurotypical group for average cluster size . There were no significant differences between predicted and obtained values for differences between English and Spanish total number correct in each task type . Results are discussed in the context of individual cognitive and linguistic profiles of the TBI participants .
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Verbal fluency in bilingual TBI was compared with healthy bilingual verbal fluency. Level of language impairment appeared to be an important predictor of performance. Parallel impairment of languages may be a common recovery pattern in bilingual TBI. Language control may be a common feature of bilingual TBI sequelae. Number of switches but not cluster size was associated with lower performance.
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S0021992418300030
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The objective of this study was to investigate the development of consonant inventory and accuracy in pediatric cochlear implant recipients and compare their performance to typical hearing children . One hundred and twenty nine children with CIs implanted between 638 months of age and 30 age matched children with TH participated in this study . Spontaneous speech samples were collected at 3.5 and 4.5 years chronological age and the first 100 different words spoken by each participant were transcribed . Two consonant production measures were subsequently calculated to assess consonant acquisition and mastery . The percentage of Consonants Correct was used for measuring accuracy and Consonant Diversity an inventory measure was used to identify the number of different consonants spoken by each participant . Repeated measures analyses of variance were conducted to examine the differences in consonant production scores based on presence of CI participants and chronological age at data collection . CI recipients displayed lower consonant production scores compared to TH children . Children with the most device experience performed on par with their TH peers . The two measures used in this study together appear capable of comprehensively describing the changes in consonant production skills of children . Results from this study indicate that while most CI participants display lower scores compared to TH children many of the CI users are able to produce speech sounds on par with TH children .
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On average children with CIs lag behind TH children when producing consonants. CI recipients display higher production scores with increasing device use. Very early implanted children display production on par with TH children.
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S0021992418300273
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The purpose of this follow up study to Ludlow was to examine potential sources of variability within attributional ratings adults assigned to child speakers affected by either Specific Language Impairment or Attention Deficit Hyperactivity Disorder . Factors considered were raters gender or Rater Female the reported gender of the speakers or Speaker Female and the type of neurodevelopmental disorder involved . Eighty participants rated brief transcribed narratives previously produced in Ludlow by boys affected by either SLI ADHD or who had typical neurodevelopment . Narratives were presented to raters as having been generated by either a boy or a girl . After reading each narrative participants provided ratings in response to 15 questions about the narrative the child speakers attributes and family background . Analyses revealed a significant main effect for speaker group such that raters assigned more pejorative attributes to children with a disorder across all dimensions . Significant speaker gender main effects were limited to questions targeting the speakers behavioral attributes . Results obtained in this study with transcription stimuli replicated previous reports that had used audio stimuli . These findings contribute to a growing body of research documenting the presence of robust multidimensional implicit negative biases among most individuals towards children displaying language differences associated with common neurodevelopmental disorders .
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Gender of rater did not influence ratings of children male or female . Children with disorders are rated more negatively than typical neurodeveloping children. Male children are perceived as having more potential behavior issues than female children. There was a highly similar rating pattern between orthographic transcriptions and audio retellings of the same narratives.
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S0021992418300315
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Stuttering and speech sound disorder may co occur during early childhood although the exact rate of comorbidity in a community cohort sample remains unknown . In isolation both disorders have the potential for long term negative effects . Comorbidity rates of 16 46 reported in previous studies were based on parent report speech language therapist surveys case file audits or direct observation studies from clinical samples . Rigorous methodology utilising a prospective longitudinal community cohort design is required to support these previous findings . First to identify the proportion of children with comorbid stuttering and speech sound disorder at 4 years of age drawn from a community cohort study . Second to compare demographic and clinical features of this comorbid diagnosis group compared to children with no diagnosis of either disorder or those with either disorder in isolation . Participants were drawn from a prospective longitudinal community cohort study at 4 years of age Of the 160 children diagnosed with stuttering between 2 and 4 years of age 6.88 The prevalence of comorbid stuttering and speech sound disorder was lower in a community cohort compared to that reported in clinical studies . Higher rates reported in clinical samples may be due to increased parental help seeking behaviour when the two disorders co occur . Subsequently these children may present to clinics more frequently . Accurate representation of prevalence allows for population specific research on best practice assessment and intervention . Currently little is known about how best to manage this caseload therefore more research is required in this area including the determination of prognostic variables to provide efficient and effective management .
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Community cohort prevalence of comorbid stuttering and SSD was 0.68 . Clinical prevalence was 6.88 11 160 children who stuttered also had a SSD . Clinical prevalence is lower than previously reported between 1646 . Overall sample size was small with a large number of comparisons conducted. Not enough evidence suggesting significant differences across most comparisons.
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S0021992418300960
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Huntingtons disease is a neurodegenerative disease causing motor symptoms along with cognitive and affective problems . Recent evidence suggests that HD also affects language across core levels of linguistic organization including at stages of the disease when standardized neuropsychological test profiles are still normal and motor symptoms do not yet reach clinical thresholds . The present study aimed to subject spontaneous speech to a more fine grained linguistic analysis in a sample of 20 identified HD gene carriers 10 with pre manifest and 10 with early manifest HD . We further explored how language performance related to non linguistic cognitive impairment using standardized neuropsychological measures . A distinctive pattern of linguistic impairments marked off participants with both pre manifest and manifest HD from healthy controls and each other . Fluency patterns in premanifest HD were marked by prolongations filled pauses and repetitions which shifted to a pattern marked by empty pauses re phrasings and truncations in manifest HD . Both HD groups also significantly differed from controls and each other in how they grammatically connected clauses and used noun phrases referentially . Functional deficits in language occurred in pre manifest HD in the absence of any non linguistic neuropsychological impairment and did largely not correlate with standardized neuropsychological measures in manifest HD . These results further corroborate that language can act as a fine grained clinical marker in HD which can track disease progression from the pre manifest stage define critical remediation targets and inform the role of the basal ganglia in language processing .
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Huntingtons disease HD involves changes in language along with primary motor symptoms. Linguistic change emerged in spontaneous speech prior to the onset of motor symptoms. They were largely independent of non linguistic cognitive measures. Language may be a promising biomarker of disease progression in HD.
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S002199241830176X
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Communication partner training could be employed to train people working in the community to facilitate interaction with individuals who live with a variety of communication disorders . However current evidence syntheses are limited to a single disorder and focus on a variety of familiar and unfamiliar communication partners . An understanding of the scope of literature across the evidence base of acquired neurological populations may provide a better basis to develop interventions and future research tailored for community workers . To explore the scope of literature on paid worker and unfamiliar partner communication training for acquired neurogenic communication disorders with a focus on describing 1 the types of communication disorders addressed by interventions 2 the types of learners who received the interventions 3 the nature of the interventions and 4 the reported effects on trainees and people with a communication disorder . A scoping review was conducted . Studies were selected by a systematic keyword search undertaken through four databases . Eligibility criteria included studies that reported an intervention directed at paid workers or unfamiliar partners where the primary goal was to improve communication with people with acquired neurogenic communication disorders reported original results contained quantitative or qualitative data on the effects of the intervention were written in English or French and were published in a peer reviewed journal . The PRISMA ScR was used to guide design and reporting of the scoping review . Seventy publications met the inclusion criteria . Interventions were mostly disorder specific and addressed communication with people with dementia aphasia or traumatic brain injury . 15 70 studies examined training programs that were not restructured to a specific population . Learners were mostly working or studying in the healthcare field and only 2 70 studies included community workers without primarily health training . Sixty different interventions were reported and were mostly delivered by speech language pathologists . Training varied in terms of duration and content but many shared training methods . Nearly all studies demonstrated positive results 23 26 studies suggested that paid worker and unfamiliar partner communication training may increase the knowledge of trainees 24 26 studies suggested that it could improve their confidence when interacting with people with a communication disorder and 44 46 studies suggested that it could improve the trainees communication abilities . A small developing evidence base exists for communication training programs for paid and unfamiliar communications partners that focuses beyond a single diagnosis or disorder . However there is very limited knowledge on interventions for community workers from non health professions . Future research should focus on the evaluation of existing programs tailored to or explicitly designed for this context with the aim of identifying active ingredients that lead to improved and sustainable outcomes .
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Information is needed to develop a communication partner training CPT programs for workers in the community. A vast majority of CPT programs are disorder specific. Almost all trainees were working or studying in the health care field. CPT programs varied in terms of duration and content but many shared training methods. CPT programs tailored to or explicitly designed for community workers should be developped and studied.
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S0021992418302107
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Joint attention is considered a prerequisite for language development . Although language is one of the most impaired domains in Down syndrome few studies have examined the relationship between caregiver behavior during episodes of joint attention and vocabulary development in these children . Consequently our primary aim was to analyze the behaviors of caregivers of children with DS and of children with typical development in the early stages of vocabulary development . A second objective was to examine the kind of words that caregivers use to refer to the object that is the focus of attention . We also consider the concurrent relationship between joint attention and vocabulary development in both groups of children . We studied 28 children with DS and 28 children with TD individually matched on mental age and gender and their respective caregivers . The mean mental age for children with DS and children with TD was around 12 months . The mean chronological age of caregivers of children with DS and children with TD was around 35 years . Each child and his or her caregiver were video recorded during a free play session involving different objects . Although the total time engaged in joint attention was greater among caregivers of children with DS caregivers of both groups of children were more likely to direct than follow their childs attentional focus . The caregivers of children with DS used a greater number of appropriate terms to refer to the object of attention . We found no significant correlation in either group of children between vocabulary development and joint attention behaviors . The results may be due to the fact that the children studied are still very young in developmental terms and have yet to develop all the skills required for joint attention . At this early stage directing the childs attention would promote the development of joint attention . A possible explanation for the lack of a correlation between vocabulary development and joint attention is that children may use an associative mechanism in the early stages of lexical learning and hence the learning of new words is a slow process .
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Caregivers of children with DS and of children with TD are equally directive. Directiveness is adaptive and of functional value in early stages of development. Caregivers of children with DS used more appropriate terms to name objects. No relationship between joint attention and vocabulary in children of either group. Children may use an associative mechanism in the early stages of lexical learning.
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S0021992418302119
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Acoustic measurements have shown that the speech of hearing impaired children deviates from the speech of normally hearing peers . The aim of the present study is to examine whether listeners with varying degrees of experience with childrens speech perceive a difference in the overall speech quality of seven year old NH children and their HI peers who received a device before the age of two . Short speech samples of seven children with NH seven children with an acoustic hearing aid and seven children with a cochlear implant were judged by three groups of listeners in a comparative judgement task . In this task listeners compared stimuli in pairs and decided which stimulus sounded better leading to a ranking of the stimuli according to their overall speech quality . The ranking showed that the overall speech quality differed considerably for HI and NH children . The latter group had a significantly higher overall speech quality than HI children . In the group of HI children children with CI were ranked higher than children with HA . Moreover length of device use was found to have a significant effect in the group of children with CI longer device experience led to better ratings . This effect was significantly less strong in HA children . No significant differences were found between the three groups of listeners . Listeners agree that the speech of NH children sounds better than the speech of HI children . This result indicates that even after almost seven years of device use the speech of HI children still differs from the speech of NH children . The overall speech quality of CI children was better than that of HA children and this effect increased with longer device use . No effect of listeners experience with childrens speech was established .
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Speech quality of hearing impaired and normally hearing children differs. Seven years of device use do not suffice to reach the same speech quality level. Cochlear implanted children perform better with increased length of device use. Speech quality perception is comparable for experienced and inexperienced listeners. Comparative judgement is a feasible alternative to traditional rating scales.
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S0021992418302181
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To evaluate the efficacy of the combination of a speech bulb with an intensive speech therapy program in hypernasal participants with cleft palate . Twenty hypernasal speakers with cleft palate who were wearing speech bulbs underwent an intensive speech therapy program of 45 sessions over 3 weeks . Three experienced speech language pathologists rated the participants speech recordings before and after intensive speech therapy with and without the speech bulb . Nasometric recordings and long term averaged spectra were also analyzed using repeated measures ANOVAs . The ANOVA of the hypernasality ratings showed significant effects of therapy 15.97 p .001 speech bulb and a therapy speech bulb interaction effect 22.30 p 0.001 . The most favorable listener ratings of hypernasality were obtained post therapy when participants were wearing their speech bulbs . Without the speech bulb intensive speech therapy by itself did not result in a significant improvement . With speech bulb nasalance scores for high 14.07 p .001 and low pressure 14.84 p .001 sentences were significantly lower post therapy providing preliminary evidence that an intensive speech therapy program may enhance the effect of a speech bulb . Before and after comparisons of individual nasalance profiles demonstrated variable improvement in 15 participants no progress in 2 participants and more severe hypernasality after therapy in 3 participants . Long term averaged spectra corroborated the findings of the perceptual analysis . Based on a frequency bin from 201 to 300Hz there was a significant within subject effect for with and without speech bulb 4.54 p .047 as well as for before vs. after session 7.14 p .015 . The speech bulb in combination with intensive speech therapy resulted in improved oral nasal balance for the majority of participants . More research is needed to investigate long term outcomes as well as individual factors contributing to therapy success .
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Intensive speech therapy associated with a speech bulb can reduce hypernasality. Nasometry and spectrography can be used to corroborate perceptual findings. A new method for spectrography of oral nasal balance disorders is presented.
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S0021992418302314
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Stuttering affects people in individual ways and there are multiple factors which may influence a persons goals when seeking therapy . Even though there is a common consensus that speech language pathologists should discuss the individuals goals and expectations for stuttering therapy and outcomes few studies have systematically investigated this issue . This study is part of a wider ranging treatment study of individualized stuttering management tailored to the participants personal goals and preferences . A mixed method multiple single case design was used to address the research questions . Twenty one adults age 2161 years took part in a pretherapy interview which also included two quantitative measures the Client Preferences for Stuttering Therapy Extended version and the Overall Assessment of Speakers Experience of Stuttering Adult version . Findings from the study sample was compared with a Norwegian reference group in order to check for the representativeness of the study sample . Quantitative data showed that most participants wanted to focus on both physical and psychological aspects of therapy and that 95 considered to gain a sense of control over the stuttering as important . Participants perspectives on their speaking ability and stuttering interference in communication were identified as central factors particularly in social and professional settings . These outcomes aligned well with the finding of avoidance behaviors such as avoiding words and speaking situations . Qualitative data identified four main areas that the participants wanted to improve speech fluency emotional functioning activity and participation and understanding of their stuttering . The study confirms that multiple and individual factors may influence the persons goals for therapy . Goals were mainly anchored in participants wish of better coping in real world settings . A high degree of avoidance behavior was reported suggesting that anxiety and in particular linguistic related anxiety needs to be taken into account when addressing social anxiety in fluency disorders .
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Identifies a multifactorial individualized approach to the treatment of adult stuttering. Describes the alignment of a client centered approach to agreed outcomes. Uses a mixed method design to explore participants therapy goals. Highlights the need to consider individual differences when planning treatment. Therapeutic goals were based on the principles of coping in real life settings.
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S0021992418302508
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Two studies assessed implicit and explicit attitudes toward stuttering and those who stutter among speech language pathologists . In Study 1 15 SLPs completed the Stuttering Implicit Association Test a measure of implicit attitudes toward stuttered speech . In Study 2 40 SLPs provided explicit attitudes about individuals who stutter assessed via self report ratings of an adult who stutters and one who does not . Participants also completed measures of experience with stuttering . As a group clinicians displayed negative implicit attitudes toward stuttering . Explicit attitudes toward a person who stutters were positive albeit less positive than attitudes toward a person who does not stutter . Amount of prior exposure to stuttering among these experienced SLPs was not significantly associated with either implicit or explicit attitudes . These findings highlight the importance of evaluating both implicit and explicit attitudes toward stuttering . The finding of positive explicit attitudes but negative implicit attitudes among similar samples of SLPs underscores the need to study implicit attitudes toward stuttering . Considering only explicit attitudes could lead to incomplete conclusions about the complex nature of attitudes toward stuttering .
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Findings highlight the importance of evaluating both implicit and explicit attitudes toward stuttering. Positive explicit attitudes toward those who stutter were found among a sample of SLPs. Negative implicit attitudes were found among a similar sample of SLPs. Differences between explicit and implicit attitudes underscore the need to study both types of attitudes to stuttering.
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S0021992418302636
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Individuals with 5p deletion syndrome ten times over a period of five years . His scores were compared to those of typically developing infants aged eight to 20 months . It was found that the subject followed a considerably delayed but not deviant developmental trajectory in three areas receptive vocabulary productive vocabulary and communicative gestures compared to typically developing infants and toddlers . The speech and language problems of individuals with 5p deletion syndrome which have been documented in the domains of phonetics and phonology and grammar also extend to gestural and lexical development . The findings of this study will have clinical implications for assessment in that a broad assessment of gestural and lexical skills should be carried out as early as possible as a basis for interventions to improve communicative skills .
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Communicative gestures develop over time in 5p deletion syndrome. Receptive and productive vocabulary develop like in typically developing children. Gestural and lexical skills show a considerably protracted development.
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S0021992419300061
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Speech Language Pathologists working with students from culturally and linguistically diverse backgrounds are encouraged to be familiar with nondiscriminatory testing and dynamic assessment procedures . Little is known however about the extent to which SLPs implement these methods into their clinical practice . The current study explores the assessment and intervention practices used by SLPs in two states in the US for students who speak African American English including the types and frequency of clinical practices . 247 SLPs completed an online survey regarding clinical practices for students who speak AAE as well as a questionnaire regarding their knowledge of the linguistic features of AAE . Half of SLPs reported using modified or alternative assessment practices the majority of the time or some of the time for students who speak AAE however SLPs reported using modified or alternative treatment practices less often . Modified scoring of standardized assessments and selecting different intervention strategies were the most commonly reported clinical practices . Knowledge of linguistic features of AAE was a significant predictor of the frequency with which SLPs report implementing modified or alternative assessment and intervention practices and SLPs with the highest levels of knowledge of AAE utilize different clinical practices than those with lower levels of knowledge of AAE . Additional information is needed about the most effective clinical practices for students who speak AAE and the barriers SLPs face to implementing nondiscriminatory clinical practices .
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50 of SLPs use modified alternative assessments for students who speak AAE. Modified scoring was the most common assessment practice. Modified alternative practices were more common for assessments than interventions. SLPs who modify often have higher knowledge of AAE than SLPs who modify less often.
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S0021992419300176
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Children with developmental language disorder appear to be challenged with word reading problems in a number of ways yet few investigations in this area are known . Of interest in this exploratory study was how children with DLD decode and recognize words and word parts with irregular graphemic properties . Sixty children with DLD and typical language in 2nd5th grade and 19 college aged adults were asked to decode individual phonograms words and pseudowords and to identify phonogram forms in a recognition task . Responses were categorized as either reflecting graphophonemic or target or unrelated or incorrect responses . According to logistic regression analyses children with DLD at each grade level used higher levels of serial letter sound correspondences in their decoded productions of isolated phonograms real and pseudowords relative to their grade matched peers with TLD and to adults . DLD2 and TLD1 groups performed similarly across the three production tasks . Results on the phonogram recognition task reflected mixed patterns of responding across child and adult groups . Overall DLD participants made more LS only selections than did TLD participants although DLD and TLD 4th5th graders performed similarly to each other in their relative selections of target versus target LS phonogram forms . Children with DLD appear to demonstrate protracted stages of graphophonemic serial decoding . A gradual catching up trend seems to occur over 2nd5th grades on certain aspects of decoding . A number of developmental considerations and clinical implications for children with DLD are drawn from this study .
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Children with DLD use more serial decoding than chunking of opaque phonogram forms. Children with DLD serially decode more words and pseudowords than typical peers. Children with DLD recognize English phonograms based on letter sound properties. How do 2nd5th grade children with and without DLD compare to college aged adults in phonogram decoding and recognition.
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S0021992419300280
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this study evaluated the effectiveness of different speech techniques for the rehabilitation of hypernasality in children with a cleft palate with or without a cleft lip . The impact of speech rate and or mouth opening was investigated on both hypernasality and speech intelligibility . thirteen patients with CPL and perceived hypernasality and 13 age and gender matched children without CPL were included . Children were asked to read an oral and oronasal text passage in ten different speaking conditions where speech rate and or mouth opening was manipulated . Outcome measures included instrumental measurements of hypernasality and perceptual ratings of speech intelligibility and hypernasality . speaking with a lower speech rate had a statistically significant positive influence on objective measures of hypernasality in both groups especially when elicited by a metronome . An increased mouth opening and the combination of both techniques was only effective in the control group . Moreover it was found that children without CP L were less intelligible when speaking with a decreased mouth opening . a metronome controlled decrease of speech rate had a positive influence on objective measures of hypernasality both in children with and without CPL . However present study could not provide any evidence that speaking with increased mouth opening reduces objective and perceptual measures of hypernasality in children with CPL . Further research investigating the use of these techniques is necessary .
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Increased mouth opening did not influence measures of hypernasality in children with CPL. Decreased mouth opening decreased speech intelligibility in children without CPL. A slower speech rate reduced nasalance values in children with and without CPL.
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S002199241930053X
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Longitudinal research into the development of prosociality during childhood contributes to our understanding of individual differences in social and emotional outcomes . There is a dearth of literature on the development of prosociality in children with Developmental Language Disorder . Data from the UK based Millennium Cohort Study was used to investigate prosociality from age 5 to 11 years in 738 children at risk of Developmental Language Disorder and 12 972 children in a general population comparison group . Multilevel mixed effects regression models were run to investigate the mean change in prosociality and latent class growth analysis was used to identify heterogeneous groups of children who shared similar patterns of development . Overall children at risk of DLD were less prosocial at age 5 and although they did become more prosocial by the age of 11 they did not reach the same levels of prosociality as those in the GP group . Subsequent sub group analysis revealed four distinct developmental trajectories stable high stable slightly low decreasing to slightly low and increasing to high . Children at risk of DLD were less likely than those in the GP group to be in the stable high class and more likely to be in the stable slightly low class . For children at risk of DLD being prosocial was protective against concurrent social and emotional difficulties . But being prosocial in early childhood was not protective against later social and emotional difficulties nor did the absence of prosociality in early childhood make social and emotional difficulties in middle childhood inevitable . Rather the presence of prosociality in middle childhood was the key protective factor regardless of prosociality in early childhood . Prosociality is not a key area of concern for children at risk of DLD . Instead it is an area of relative strength which can be nurtured to mitigate social and emotional difficulties in children at risk of DLD particularly in middle childhood .
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In this longitudinal study we focussed on children at risk of DLD. We found that. Prosociality is an area of relative strength. There is considerable heterogeneity in the development of prosociality. Low prosociality in early childhood does not predict later psychosocial difficulties. Being prosocial in middle childhood is protective against concurrent psychosocial difficulties.
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S0021992419300577
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Against the backdrop of hundreds of studies documenting negative stereotypes and stigma held by the public regarding people who stutter a substantial number of investigations have attempted to improve public attitudes and measure their results with a standard instrument the This study sought to determine what properties of interventions and demographic variables were predictive of least to most successful interventions . Preliminary to that however it required the division of samples into clearly differentiated categories of success . Twenty nine different study samples containing 934 participants were categorized into four levels of success of interventions according to pre versus post Interventions characterized by high interest or involvement meaningful material and content that respondents found to be relevant but not excessive tended to be associated with more successful interventions . In contrast demographic variables were weak predictors of intervention success . The authors hypothesize that maximally effective interventions reflect optimal matches between participant characteristics and intervention features although the critical variables in each are not yet apparent .
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pre and post means classified 29 different samples into 4 success categories. Three factors of interventions predicted success in improving stuttering attitudes. These were audience interest personal connection and relevant information. Demographic variables did not predict intervention success. Effective interventions reflect optimal matches between interventions and audiences.
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S0021992419300814
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Well documented benefits of noise reduction technologies in laboratories do not always yield a significant difference in real world acoustic environments . Many possible reasons were proposed and studied to address this discrepancy . The purpose of this study was to examine the effectiveness of different noise reduction strategies for cochlear implants in real world acoustic environments . Sixteen listeners were fit with hearing aid preprocessors with electrical outputs and cochlear implant speech processors receiving the electrical inputs . The preprocessors were programmed to 1 no noise reduction omnidirectional microphone 2 moderate noise reduction a combination of omnidirectional and adaptive directional microphone modes with modulation based noise reduction and 3 maximum noise reduction adaptive directional microphone in all frequency channels with NR . Listeners listened to sentences in a noisy caf a noisy restaurant and a quiet hotel lobby . They were instructed to rate the overall sound quality preference ease of listening speech intelligibility and listening comfort of sentences using a paired comparison categorical rating paradigm . Results indicate cochlear implant listeners had no microphone preference in quiet but they preferred adaptive directional microphones in noisy environments . The paired comparison categorical rating paradigm is a viable means to evaluate the benefits of signal processing strategies in real world acoustic environments .
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CI listeners perceived better sound quality with adaptive directional microphone in noisy real world environments. CI listeners preferred more aggressive form of directional mode in noisy environments. The paired comparison categorical rating paradigm was a viable tool to assess directional benefits in real world environments. It is beneficial to evaluate signal processing algorithms in multiple sound quality dimensions.
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S002199241930098X
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Previous studies have provided inconsistent evidence concerning the association between delayed retrieval of story information from long term memory and retrieval of words on verbal fluency tasks . The current study looks for shared retrieval mechanisms in these tasks from childhood to old age . Three hundred and eighty participants performed tasks of story recall digit span phonemic fluency and semantic fluency . Significant correlations between delayed story recall and both fluency tasks emerged in all age groups and the contribution of delayed story recall to fluency performance remained significant when analyzing the combined effects of story recall and digit span . These findings suggest that retrieval of information through story recall and retrieval of words on fluency tasks may share similar cognitive components .
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Delayed story recall associates with phonemic and semantic fluency. Associations between story recall and fluency appear across a wide age range. Working memory predicts phonemic fluency only and only in adults. Retrieval of story details and retrieval of words may rely on similar components.
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S0021992419303119
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At present there is limited information on the nature and extent of speech language pathology services in the U.S. specific to people with mild aphasia . The goal of the present study was to determine how speech language pathologists perceive the assessment treatment and discharge of PWMA . According to anecdotal reports from SLPs and PWMA current services may be inadequate and those with more severe aphasia types are being prioritized .
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There exists limited information on SLP services for with mild aphasia PwMA . According to anecdotal reports from SLPs and PwMA current services may be inadequate. SLPs who completed this survey reported appropriately serving PwMA. SLPs also note a critical need for evidence to guide future practice. PwMA have unique needs and the potential to return to work.
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S0021992420300599
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In addition to anatomical and physiological problems children with a cleft palate often face psychosocial difficulties . A complex interaction between patient and environment may induce these problems . Based on the literature speech disorders may negatively influence a listeners judgement of a speaker . Therefore the aim of the present study was to investigate the attitudes of peers toward the speech of children with CP L. Sixty nine typically developing children judged audio recorded speech samples of nine children with CP L and three control children based on three attitude components i.e . cognitive affective and behavioral . A speech intelligibility percentage was determined for each speaker based on transcriptions by 23 nave adult listeners . Furthermore two speech language pathologists perceptually rated the degrees of hypernasality nasal airflow and articulation errors . A correlation was calculated between the attitude components and the speech intelligibility percentage and the attitude components and perceptual judgements . Additionally the possible influence of age and gender of the listeners on their attitudes was explored . A significantly positive correlation was found between the speech intelligibility percentage and the attitude components when a child was understood better more positive attitudes were measured . A significantly negative correlation was found between perceptual judgements and all attitudes components presence of more hypernasality nasal airflow or articulation errors resulted in more negative attitudes . Furthermore boys and younger children seem to have more negative attitudes compared to girls and older children . This study provides additional evidence that peers show more negative attitudes toward children with more speech disorders due to CP L. Further research may explore the possible impact of age and gender on attitudes of peers . Intervention should focus on changing the cognitive affective and behavioral attitudes of peers in a more positive direction and encouraging the psychosocial development of children with CP L .
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Peers show more negative attitudes toward children with less intelligible speech. Boys show more negative attitudes compared to girls. Young children show more negative attitudes compared to older children. Intervention should focus on cognitive affective and behavioral attitudes of peers.
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S0021992420300617
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There is a lack of studies investigating articulation skills in bilingual children with a migration background . Therefore the present study compared articulation skills in bilingual Turkish Dutch Moroccan Arabic Dutch children with migration background and monolingual Dutch children without migration background . Moreover possible factors influencing articulation skills were determined . 15 bilingual Turkish Dutch 15 bilingual Moroccan Arabic Dutch and an age and gender matched group consisting of 15 monolingual Dutch children all aged between 6 and 7 years and living in Flanders were included in the present study . Articulation was evaluated using a picture naming test . Speech samples were transcribed phonetically and articulatory analysis including a phonetic inventory and phonetic and phonological analyses was performed . The phonetic analysis made a distinction between distortions substitutions additions and omissions . For the phonological analysis a distinction between syllable structure processes substitution processes and assimilation processes was made . Moreover parents were administered a self report questionnaire to determine possible factors influencing articulation skills . A statistically significant difference in additions was found when comparing the three groups . Interestingly both the Turkish Dutch and Moroccan Arabic Dutch groups used additions that were not present in the Dutch group and . Concerning phonological analysis it was found that deletions of final consonants were more present in the bilingual groups compared to the monolingual group . Moreover statistically significant effects of origin home language and language preference of the child were found on presence of both phonetic errors and phonological disorders . Findings of the present study showed that some phonetic errors and phonological processes were more present in the group of bilingual children with migration background compared to the group of monolingual children without migration background . Interestingly phonetic errors and phonological processes were more present when the child had a Turkish origin or when the dominant language at the home environment was Turkish or when the preferred language of the child was Turkish . Given the increased attention to migration findings of the present study are highly important for speech language pathologists teachers and more generally all professionals working with bilingual populations with a Moroccan Arabic or Turkish migration background .
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Turkish origin was found to influence presence of phonetic phonological processes. Turkish as dominant language was found to influence presence of phonetic phonological processes. Turkish as preferred language was found to influence presence of phonetic phonological processes. Some phonetic phonological processes were more present in the group of bilingual children
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S0021992420300629
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Language decline has been associated with healthy aging and with various neurodegenerative conditions making it challenging to differentiate among these conditions . This study examined the utility of linguistic measures derived from a short narrative language sample for 1 identifying language characteristics and cut off scores to differentiate between healthy aging Primary Progressive Aphasia Mild Cognitive Impairment and Alzheimers dementia and 2 differentiating among PPA variants in which language is the primary impairment . Participants were 25 neurologically healthy English speakers 20 individuals with MCI 20 with AD and 26 with PPA . Narrative language samples of the Cookie Theft Picture of persons with healthy aging MCI and AD were retrospectively obtained from the DementiaBank database word retrieval and sentence grammaticality . PPA and AD groups did not differ on language measures . Agrammatic PPA participants scored lower than logopenic and semantic PPA groups on several measures while logopenic and semantic PPA did not differ on any measures . Measures derived from brief language samples and analyzed using mostly automated methods are clinically useful in differentiating PPA from healthy aging and MCI and agrammatic PPA from other variants . The sensitivity and specificity of these measures is modest and can be improved when coupled with clinical presentation .
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PPA scores are lower than healthy adults and MCI on fluency word retrieval and grammaticality. PPA and AD groups did not differ on language measures. Agrammatic PPA scores are lower than logopenic and semantic PPA on rate mean length and verbs utterance.
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S0021992420300630
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The aims of the current study were to determine age related changes to the phonatory and articulatory subsystems and to investigate an exploratory model of intelligibility for healthy aging based on phonatory and articulatory measures . Fifteen healthy older adults and 15 younger adults participated in instrumental assessments of the phonatory and articulatory subsystems . Speech intelligibility was determined by five listeners during multi talker babble . Older adults displayed shorter maximum phonation time greater airflow during sentence reading and lower cepstral peak prominence and CPP Aging affects the phonatory and articulatory subsystems with implications for speech intelligibility . Phonatory cepstral spectral measures were associated with speech intelligibility changes suggesting that changes in voice quality may contribute to reduced intelligibility in older adults . Pertaining to articulation slower tongue movement speed likely contributed to reduced intelligibility in older individuals .
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Phonatory age related changes included greater airflow and lower cepstral measures. Aging induced slowing of tongue movements was observed for the articulatory system. Cepstral spectral measures except CPP predicted age related intelligibility change. Maximum speed was a significant contributor to age related intelligibility change.
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S0021992420300642
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In the course of productive phonological development fricatives are among the last speech sounds to emerge and to be mastered by children probably because of the high degree of articulatory precision they require or because of difficulties with their perception . Children with cochlear implants face additional difficulties with fricative perception since high spectral frequency components are shown to be especially difficult to perceive with a cochlear implant . Studying fricative production in children with CIs allows to study how the partial transmission of speech sounds by cochlear implants influences childrens speech production and therefore to explore how perceptual abilities influence the late stages of phonological development .
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Children with cochlear implants CIs produce fricatives differently from their peers with NH. Children with CIs produce f and s with lower centers of gravity than children with NH. Children with CIs produce labiodentals f with a smaller standard deviation. Children with CIs show less anticipatory coarticulation in consonant vowel sequences. Production in older children with CIs is approaching that of children with NH.
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S0021992420300654
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The identification of an early and objective marker of language impairment in autism spectrum disorder has the potential to lead to earlier language intervention for affected children . The mismatch negativity a passive auditory evoked potential offers insight into the brains ability to direct attention to novel sounds . Since exposure to speech is necessary for learning to map meaning onto phonemes we predicted slower MMN responses to speech sounds would indicate presence of language impairment in ASD . We explored the relationship between MMN latency in children ages 510 with ASD plus language impairment ASD minus language impairment and typically developing children during an auditory oddball experiment presenting speech and pure tone sounds . Contrary to our prediction children with ASD LI demonstrated decreased MMN latency in the left hemisphere in response to novel vowel sounds compared to children with ASDLI and TD controls . Parent responses to the Sensory Experiences Questionnaire revealed that all participating individuals with ASD were hypersensitive to sounds . Our results lend support to the theory that some children with ASD LI have increased connectivity in primary sensory cortices at the expense of connectivity to association areas of the brain . This may account for faster speech sound processing despite low language scores in these children . Future studies should focus on individuals with language impairment and hyper or hyposensitivity to sounds .
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Some children with autism and language impairment are faster at detecting changes to sounds. Change detection timing is the same between controls children with autism and typical language. Research should continue to explore change detection as a marker of language impairment in autism.
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S0021992420300666
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The behavioral effects of lexical priming are well studied in the cognitive sciences . Clinical use of the term and widespread implementation of priming based behavioral interventions has remained limited . This is despite the fact that response contingent cueing a behavioral intervention technique used during many cognitive linguistic interventions is
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Priming and cueing serve to pre engage the neural system by triggering the retrieval of linked conceptual knowledge. Differences between priming and cueing are linked to timing and conscious intentional engagement. Semantic Feature Analysis and Verb Network Strengthening Treatment are two priming based treatments used to enhance linguistic performance.
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S0021992420300678
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While there is ample evidence that monolingual children with Autism Spectrum Disorders face difficulties with narrative story telling and executive functions there is considerable uncertainty about how bilingualism impacts these skills in autism . The current study explores the effect of bilingualism on the narrative and EF skills of forty 7 to 12 year old bilingual and monolingual children with ASD as well as forty age matched bilingual and monolingual children of typical development . Narrative production data were elicited using the Edmonton Narrative Norms Instrument which was developed to measure narrative production at a microstructural and macrostructural level . The same children were administered two EF tasks namely a global local visual attention task and a 2 back working memory task . In story telling bilingual children with ASD achieved higher scores than monolingual children with ASD on story structure complexity and use of adverbial clauses and they tended to use significantly fewer ambiguous referential forms than their monolingual peers with ASD . In the global local task bilingual children with ASD were faster and more accurate in global trials than monolingual children with ASD who tended to be more susceptible to interference from locally presented information than the other experimental groups . Higher accuracy and faster response times were also observed for bilingual children with ASD in the 2 back task . Further correlation analyses between the story telling and EF tasks revealed that bilingual children with ASD drew on a broader range of EF in narrative production than their monolingual peers . The overall findings reveal that bilingual children with ASD outperformed their monolingual peers with ASD in both the microstructure and macrostructure of their narrative production as well as in their visual attention and working memory skills .
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Bilingualism in autism enhances micro and macro structure in storytelling. Bilingualism in autism mitigates childrens detail oriented processing style. Bilingualism in autism enhances childrens working memory and updating abilities. Bilinguals with autism employ a broader range of executive functions in storytelling than monolinguals.
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S002199242030068X
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To test the psychometric properties of a newly developed Mandarin Clinical Evaluation of Language for Preschoolers Core Scale . Data were collected from 379 preschool aged participants including 81 children with language disorders associated with clinical conditions . The 155 item MCELP CS consists of five subscales vocabulary comprehension sentence comprehension vocabulary naming sentence structure imitation and story narration . The scale was used to measure the receptive and expressive language abilities of children aged 35 years and 11 months . The Peabody Picture Vocabulary Test revised was used to measure the receptive vocabulary abilities among the children . The internal consistency test retest reliability structural validity convergent validity and diagnostic accuracy were used to evaluate the scale . Differences between age groups were also examined using analysis of variance . The MCELP CS had high internal consistency and good test retest reliability . Fitting indices of the two factor model from confirmatory factor analysis including The MCELP CS is a reliable and valid diagnostic tool for language disorders of Mandarin speaking preschool children with autism CP and HI . It is appropriate to collect normative data for the MCELP CS with a large sample population of preschool children .
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The study creates a scale measuring language disorder in Mandarin speaking children. MCELP CS is beneficial in language measurement for autistic CP and HI children. MCELP CS has good internal consistency and excellent structural validity. The MCELP CS measured language comprehension and production across domains.
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S0021992420300691
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Prior studies have documented an adverse impact of stuttering on young childrens lives . These studies have relied primarily on parent reports though different caregivers may have unique experiences with children . To date no study has examined teachers perceptions of the impact in children below six years of age . Moreover the agreement between mothers fathers and teachers in proxy ratings of impact has not been examined . Caregiver agreement is important to investigate because results from varying assessments of adverse impact can influence treatment recommendations . This study sought to gain an integrated insight into 1 teachers perceptions and descriptions of the impact of stuttering on young children and 2 agreement in mothers fathers and teachers perceptions of how stuttering affects young children . The mothers fathers and teachers of 35 young children who stutter completed the Overall Assessment of the Speakers Experience of Stuttering Caregivers when reporting on observable impact while agreement was low on ratings of internal impact . The finding that teachers also perceive stuttering to have an adverse effect on young children adds to the literature of impact particularly because the teachers reported observing impact in situations that are unique to the kindergarten setting . In line with previous literature on proxy reporting our results indicate good agreement between caregivers observing the children in the same arena and fair agreement between caregivers observing the children in different arenas . The results indicate that information from more than one caregiver can contribute to an integrated assessment of impact across arenas .
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Teachers perceive young children to be affected by stuttering. Mothers and fathers ratings of overall impact indicate good agreement. Parents and teachers ratings of overall impact indicate fair agreement. Agreement was high on ratings of observable impact and low on ratings of internal impact.
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S0021992420300708
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Predictors of reading comprehension among children with SLI have been rarely studied in Spanish . Even more sparse are longitudinal studies inspecting the evolution of their reading abilities . The aim of the present study is to inspect how decoding production of grammatical ungrammatical sentences production of simple complex sentences and vocabulary predict reading comprehension among Spanish speaking monolingual school age children with SLI in two grades 2nd grade and 4th grade . Forty eight children were recruited for this study evenly grouped in two conditions SLI and Typical . Groups were balanced by gender with no differences in months of age . All children were assessed twice when in 2nd grade and when in 4
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Children with SLI perform lower than TLD children on all observed variables. Children with SLI and children with TLD significantly improve on all measures over time. Language skills predict reading comprehension differently in both groups
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S002199242030071X
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Producing speech that is clear audible and intelligible to others is a challenge for many children with cerebral palsy and children with Down syndrome . Previous studies have demonstrated the effectiveness of using the Lee Silverman Voice Treatment to increase vocal loudness and improve speech intelligibility in individuals with dysarthria secondary to Parkinsons disease and some research suggests that it also may be effective for individuals with dysarthria secondary to other conditions including CP and DS . Although LSVT LOUD targets healthy vocal loudness there is some evidence of spreading effects to the articulatory system . Acoustic data from two groups of children with secondary motor speech disorders and one with DS who received a full dose of LSVT LOUD and for whom post treatment intelligibility gains have been previously reported were analyzed for treatment effects on
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Intensive voice treatment LSVT LOUD may foster changes in articulation. Changes for children with cerebral palsy were observed in vowel duration. Changes for children with cerebral palsy were observed in acoustic vowel space. Changes for children with Down syndrome were observed in acoustic vowel space. Preliminary findings show spreading effects of LSVT LOUD to include articulation.
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S0021992420300721
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This study examined the effects of a vocabulary intervention for bilingual children that was conducted in childrens first language Spanish and included explicit instruction on cognates . We measured effects in terms of change from pre to post intervention in Spanish as well as associations with the non target language English . Participants were 12 Spanish English bilingual children aged 68 years with and without Developmental Language Disorder . Children completed the intervention in pairs for 70 minute sessions 3 days a week for four weeks . Intervention targeted 32 words using four storybooks and interactive activities that highlighted similarities across languages . Pre and post intervention measures in Spanish and English included tasks of word definition and cognate facilitation . As a group children showed improvement in definition quality and cognate naming in Spanish . There was a positive correlation between definition quality and cognate naming for the typically developing children but not for the children with DLD . All children showed positive cross language correlations on post intervention measures . Bilingual children with and without DLD have the capacity to improve in their awareness and use of cognates . Explicit teaching of cognates can be an effective tool for building vocabulary skills . Children with DLD may need additional time and support to apply their knowledge of cognates to vocabulary learning .
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First language intervention improves vocabulary knowledge in bilingual children. Bilinguals with Developmental Language Disorder name more cognates v. noncognates. Explicit cognate teaching shows potential for supporting vocabulary acquisition. Vocabulary depth is strongly associated between bilingual childrens two languages.
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S0021992420300915
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The present study aimed to assess the effectiveness of a physiologic voice therapy program based on different semioccluded vocal tract exercises in subjects with behavioral dysphonia . Thirty four participants with behavioral dysphonia were randomly assigned to one of two treatment groups 1 voice treatment with physiologic voice therapy plus vocal hygiene program and 2 vocal hygiene program only . Laryngoscopic assessment was performed in all subjects . Before and after voice therapy participants underwent aerodynamic electroglottographic and acoustic assessment . The Voice Handicap Index Voice symptom scale Vocal tract discomfort scale and self assessment of resonant voice quality were also performed . The treatment included eight voice therapy sessions . For the experimental group the exercises consisted of a sequence of seven phonatory tasks performed with four different semioccluded vocal tract exercises . Comparison for all variables were performed between experimental group and control group . Wilcoxon test showed significant improvements for experimental group for VHI VoiSs VTDS and self perception of resonant voice quality . Significant decrease for experimental groups was observed on subglottic pressure phonation threshold pressure and glottal airflow across the implemented tasks . Physiologic voice therapy based on semioccluded vocal tract exercises seems to be an effective tool to improve voice in subjects diagnosed with behavioral dysphonia . Apparently most changes should be expected in variables related to physical and functional aspects compared to objective variables . Subglottic pressure and phonation threshold pressure seem to be the most change sensitive parameters and they may reflect a reduction in phonatory effort reported by patients after voice therapy .
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Semioccluded vocal tract exercises seem to be effective for voice function. Water resistance therapy helps reducing voice complaints. Physiologic therapy improves physical and functional features of voice. Phonation threshold pressure reveals a reduction in phonatory effort after therapy.
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S0021992420300927
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Prosodic impairments occur in many clinical populations including those with autism and motor speech disorders . These impairments can negatively impact intelligibility as well as an individuals ability to signal and understand linguistic contrasts and emotions . For this study we surveyed 245 Speech Language Pathologists to assess their clinical practices with regards to prosody and to identify potential barriers to addressing prosody in the clinic . While a majority of respondents agreed that prosody was within their scope of practice they reported that they rarely assessed or treated prosody when they suspected that a client had a prosodic impairment . Overall respondents felt they were lacking in knowledge of the nature of prosody experience with clients who have prosodic impairments and knowledge of assessment and treatment methods for prosody . Recommendations include increasing training opportunities encouraging collaboration between researchers and SLPs with expertise in prosody and the development of a clinically feasible prosody assessment .
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Speech language pathologists were surveyed on practices related to prosody. Prosody is rarely assessed or treated even when a prosodic disorder is suspected. Respondents feel they lack knowledge related to prosody and its treatment. Recommendations include increased training and development of clinical tools.
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S0021992420300939
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The purpose of this study was to report on modifications we made to a standardized input based word learning treatment for two late talking toddlers . The modifications were the addition of an augmentative alternative communication device and the requirement that the children use this device or speech to communicate . We used a single subject design to track late talking toddlers progress through an input based word learning treatment which was part of a larger study . Because the input based treatment protocol was not effective for each toddler based on absent or clinically insignificant treatment effect sizes we modified the protocol . The modifications were meant to address each childs potential over reliance on nonverbal communication and the potential impact of speech sound delay . We then measured their linguistic output . Both toddlers showed no evidence of learning during the input based treatment . Each childs linguistic output increased by over 600 once we made the protocol modification and introduced the AAC device . They used both AAC and vocal speech to communicate . Both toddlers produced novel words and one began to produce multiple word combinations . While input based therapy has an evidence base and has been successful for some toddlers it may require modifications for children who have not learned the pragmatic convention of using spoken language and for children with difficulty with speech sound production .
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Demonstrated the outcome of the use of AAC with two late talking toddlers relative to vocabulary production. Highlighted characteristics of the toddlers that may have made them more receptive to AAC use. Suggested that clinicians and researchers rethink the most common recipients of AAC use. Attend to the limited literature guidance documents that advocates for AAC for children without severe disabilities.
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S0021992420300940
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One of the key principles of motor learning supports using knowledge of results feedback during high intensity motor practice rather than knowledge of performance . In the future mobile technology equipped with automatic speech recognition could provide KR feedback enabling this practice to move outside the clinic supplementing speech pathology sessions and reducing burden on already stretched speech language pathology resources . Here we employ a randomized controlled trial design to test the impact of KR vs KP feedback on childrens response to the Nuffield Dyspraxia Programme 3 delivered through an android tablet . At the time of testing ASR was not feasible and so correctness of responses was decided by the treating clinician . Fourteen children with CAS aged 410 years participated in a parallel group design matched for age and severity of CAS . Both groups attended a university clinic for 1 hr therapy sessions 4 days a week for 3 weeks . One group received high frequency feedback comprised of both KR and KP in the style of traditional face to face intensive intervention on all days . The other group received high frequency KR KP feedback on 1 day per week and high frequency KR feedback on the other 3 days per week simulating the service delivery model of one clinic session per week supported by tablet based home practice . Both groups had significantly improved speech outcomes at 4 months post treatment . Post hoc comparisons suggested that only the KP group showed a significant change from pre to immediately post treatment but the group difference had dissipated by 1 month post treatment . Heterogeneity in response to intervention within the groups suggests that other factors not measured here may be having a substantive influence on response to intervention and feedback type . Mobile technology has the potential to increase motivation and engagement with therapy and to mitigate barriers associated with distance and access to speech pathology services . Further research is needed to explore the influence of type and frequency of feedback on motor learning optimal timing for transitioning from KP to KR feedback and how these parameters interact with task child and context related factors .
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Tablet delivered treatment was favorably received by children and families. Only children provided with 100 knowledge of performance showed significant immediate gains. It is not yet clear which children are best suited to knowledge of results feedback. Both feedback conditions produced significant gains in accuracy over time.
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S0021992420300952
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Function words and more specifically articles have been widely indicated as one of the main sources of difficulty for children with Developmental Language Disorder . The present study is the first to assess the online comprehension of Spanish articles in bilingual children with DLD . In an eye tracking experiment we monitored participants eye movements as they listened to Spanish articles embedded in structurally simple sentences . Ninety six subjects from four different groups were evaluated 24 children with DLD 24 children with the same chronological age 24 younger children matched for mean length utterance and 24 adults . We calculated the proportion between the preference for the correct visual referent and a competitor object . Our results suggest that children with DLD are capable of timely comprehension of Spanish articles in real time and within simple sentence structures . However we observed a strong effect of chronological age in the sample of interest younger children with DLD are able to identify the correct referent but this preference is weaker compared to the older children with DLD . We also observed local differences between the DLD group and the other two children control groups particularly when the chronological age group is introduced as a factor . These findings suggest a developmental trajectory that is different in the DLD group relative to children with typical language development . Notwithstanding in spite of the article production difficulties previously reported children with DLD in the present sample appear to be able to comprehend Spanish articles in the current experimental conditions .
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We monitored the eye movements of children with DLD as they listened to sentences. Subject verb object sentences contrasted all forms of Spanish articles. Findings revealed a relatively intact online article comprehension by the DLD group.
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S0021992420300964
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Speech is one of the primary outcomes in individuals with a cleft of the palate with or without a cleft of the lip . Therefore it is highly important to obtain information regarding parental perceptions and expectations concerning speech therapy related cleft care . Literature investigating these parental perspectives is scarce . The present study investigated perceptions and expectations of parents of children with CP L concerning speech therapy . Eleven parents of nine children with CP L were recruited from the multidisciplinary craniofacial team at the Ghent University hospital . A qualitative design using semi structured interviews was used to collect data . Data were managed using NVIVO software version 10 and analyzed thematically . The analysis resulted in three major themes service provision patient centered care and seeking health care . Each of these identified themes were divided into three subthemes . Service provision included the effectiveness of the provided service interdisciplinary collaboration and expertise of the speech therapist . Information provision child friendly attitude and connection were categorized under patient centered care . Seeking health care included affordability practical considerations and the selection of a speech therapist . The most prominent expectation of the parents was that they wanted to see their children progress during the speech intervention . This finding supported the importance of experienced and specialized speech language pathologists in the provision of care to children with a CP L. Moreover the results showed that the majority of the parents wanted more clear and comprehensive information particularly about the treatment progress the transfer to the home environment and the prognosis . The present findings might aid SLPs and more generally all health professionals in gaining insight into parental perceptions and expectations concerning speech therapy related cleft care . Thereby treatment quality might be improved .
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Parents wanted to see their children progress as a result of the treatment. Parents want more clear accurate and comprehensive information from the SLP. Parents expect SLPs to have sufficient experience when treating a specific population.
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S0021992420300976
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Cleft lip and or palate is the most common congenital craniofacial condition . Children born with CL P are at increased risk of persistent speech difficulties related to velopharyngeal incompetence and compensatory articulation problems . It has also been reported that they achieve poorer results academically than their peers . There is a further body of evidence to suggest delayed language skills . These potentially related outcomes are often reported separately . To review published and unpublished research into the nature of difficulties related to spoken and written language across all non syndromic cleft diagnoses . To review any evidence of associations between comorbidities . A scoping review was carried out in October 2016 and updated in June 2019 following published methodology . A search of the literature over the two time points found 38 papers in total . Three main themes were found oral language skills reading and auditory processing difficulties . There is evidence of early language delay in children born with CL P. Evidence of persistent oral language problems is less conclusive . Many studies have reported scores within the average range for language auditory processing and reading but poorer outcomes when compared to non cleft control groups . However studies have used a range of outcome measures making comparisons difficult . Moreover there is no clear evidence how these difficulties might relate to speech outcomes or educational achievement and no comparison to other populations with speech language and communication needs .
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International review of language and auditory processing skills in the cleft palate population. Poorer outcomes in language and auditory processing compared with non cleft peers. Scores on standardized tests of language frequently fall within the normal range. Limited correlations of skills in speech language and auditory processing. Lack of longitudinal data and comparison to other communication disorders.
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S0021992420300988
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Nonverbal communication specifically hand and arm movements has long been recognized and explored as a significant element in human interaction as well as potential compensatory behavior for individuals with communication difficulties . The use of gesture as a compensatory communication method in expressive and receptive human communication disorders has been the subject of much investigation . Yet within the context of adult acquired hearing loss gesture has received limited research attention and much remains unknown about patterns of nonverbal behaviors in conversations in which hearing loss is a factor .
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Hearing devices are not able to fully restore speech perception in background noise. Gestures combined with visual speech cues enhance degraded speech comprehension. Individuals modify gestures dependent on context and environment. The impact of hearing loss on audience design of gesture and gaze is unexplored. Aural rehabilitation might be enhanced with evidence based gesture intervention.
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S0021992420301003
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This paper investigated the ability of Mandarin speaking children with high functioning autism to recognize the four categories of emotional prosody namely
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Children with HFA have impairment in emotional prosody recognition. Intensity increase did not improve children with HFAs overall emotion recognition. Children with HFA have difficulty discriminating between emotions differing in valence. Children with HFA have difficulty discriminating between emotions differing in arousal.
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S0021992420301015
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To investigate the latent factors underlying signs of childhood apraxia of speech in a group of 57 children with CAS . The speech of 57 children with CAS was coded for signs of CAS . All participants showed at least five signs of CAS and were judged to have CAS by speech pathologists experienced in pediatric speech disorders . Participants were selected to represent a range of severity of CAS 30 children were verbal and 27 were minimally verbal with comorbid autism . Participants scores for each sign were converted to z scores then entered as variables into an exploratory factor analysis . Models were compared using the Akaike Information Criterion . The three factor model had the lowest AIC and best fit the data . After oblique rotation syllable segmentation slow rate and stress errors loaded most highly on Factor 1 . Groping addition of phonemes other than schwa and difficulty with coarticulation loaded most highly on Factor 2 . Variable errors loaded most highly on Factor 3 . Thus factors were interpreted as being associated with prosody coarticulation and inconsistency . Results are consistent with the three consensus criteria for CAS from the American Speech Language Hearing Association Inappropriate prosody disrupted coarticulatory transitions and inconsistent errors on repeated tokens . High loading of the syllable segmentation sign on the inappropriate prosody factor also supports the use of a pause related biomarker for CAS .
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Childhood Apraxia of Speech CAS is identified in part by a list of abnormal speech features. Those signs presumably arise from a smaller number of underlying processes. Signs were identified in the speech of a diverse group of verbal and minimally verbal children with CAS. An exploratory factor analysis revealed that those signs derived from three latent unmeasured variables. Latent variables reflected the three consensus criteria for CAS from the American Speech Language Hearing Association.
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S0021992420301027
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Developing a clearer understanding of impairments that underlie the behavioral characteristics of aphasia is essential for the development of targeted treatments and will help inform theories of speech motor control . Impairments in sensorimotor integration of speech in individuals with conduction aphasia have previously been implicated in their repetition deficits . However much less is known about the extent to which these integrative deficits occur outside of conduction aphasia and how this manifests behaviorally in areas other than speech repetition . In this study we aimed to address these issues by examining the behavioral correlates of speech sensorimotor impairment under altered auditory feedback and their relationship with the impaired ability to independently correct for online errors during picture naming in people with aphasia . We found that people with aphasia generate slower vocal compensation response to pitch shift AAF stimuli compared with controls . However when the timing of responses was controlled for no significant difference in the magnitude of vocal pitch compensation was observed between aphasia and control groups . Moreover no relationship was found between self correction of naming errors and the timing and magnitude of vocal compensation responses to AAF . These findings suggest that slowed compensation is a potential behavioral marker of impaired sensorimotor integration in aphasia .
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People with aphasia change their pitch to compensate for altered auditory feedback. Vocal pitch compensation is slower in aphasia compared with normal speakers. Slowed compensation is not correlated with self correction during naming in aphasia.
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S0021992420301039
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The purpose of the study was to determine whether listeners were less likely to believe a statement that is produced in an atypical voice as compared to a typical voice . It was hypothesized that an atypical voice characterized by abnormal roughness strain and pitch would elicit increased skepticism . This hypothesis was based on previous evidence that there are negative stereotypes against individuals who have a voice disorder and that increased difficulty processing an utterance can lead to disbelief . In Experiment 1 36 listeners rated obscure trivia statements as definitely false probably false probably true or definitely true . The statements were produced by a speaker who used their typical voice and simulated an atypical voice as well as two additional control speakers with typical voices . Experiment 2 was a replication of Experiment 1 with a new set of 36 listeners and a new set of speakers . In addition Experiment 2 examined whether reduced credibility was due to negative stereotypes and or processing difficulty through questionnaire data and correlation analyses . The results were largely consistent with the hypothesis that statements produced in an atypical voice would be perceived as less credible . In both experiments the percentage of definitely false ratings was higher for the atypical voice than for the typical voice and control voices with a large effect size in Experiment 1 and a medium effect size in Experiment 2 . Further Experiment 2 suggested that reduced credibility was due to negative stereotypes but not processing difficulty . The current study reveals a social consequence of having a voice disorder i.e . decreased perceived credibility with implications for job related success .
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Trivia statements were rated as definitely false more often when produced in an atypical voice. Study introduces a new method for assessing perceptions of people with a communication disorder. Findings suggest that having a voice disorder can reduce perceived credibility. Findings have negative implications for job related success.
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S0021992420301052
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We assessed audience response systems based evaluation of intelligibility with a view to find a valid and reliable intelligibility measure that is accessible to non trained participants . In addition we investigated potential listener differences between pediatric speech and language pathologists and untrained adults . Sixteen one minute samples of connected speech were compiled collected from 14 children with a speech sound disorder and two children with typical speech . 16 SLPs and 13 untrained adults participated in a series of ARS listening sessions where they were fitted with headphones and hand controls and instructed to click a button whenever they did not understand the child speaking . Listeners button clicks were registered and for each speech sample totaled into an intelligibility index . The proportion of syllables perceived correctly based on orthographic listener transcripts was used as a reference score of intelligibility . The ARS based intelligibility scores correlated strongly with the intelligibility reference score . Reliability was high across listener groups and weaker for single listeners . No significant difference was found between the evaluations of SLPs and untrained adults . ARS based evaluation offers a valid and reliable measure of intelligibility of particular value in research as a practical tool for collecting input from listeners without experience or knowledge of SSDs . We stress that the ARS design presupposes a listener panel and that evaluations obtained from individual listeners are predictably inadequate in terms of reliability .
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Audience Response System ARS based scores of intelligibility are valid. ARS based intelligibility scores need to be based on a panel of listeners. Panels of clinicians and untrained listeners provide similar intelligibility scores. ARS based evaluations are useful primarily in a research context
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S0021992420301064
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With the passage of the Americans with Disabilities Act Amendments Act of 2008 the definition of disability was expanded and the terms speaking hearing and communicating were given status as major life activities . Therefore any communication disorder which substantially limits these major life activities in the workplace can qualify as a disability under the law . This legal protection means that no employer can ever ask about the presence of a communication disorder and a job applicant is never required to disclose their communication disorder during the hiring process . However this right to refrain from disclosure potentially places job applicants in a difficult situation . Applicants can choose to remain silent about their disorder and hopefully avoid hiring discrimination yet the only way that workplace accommodations can be legally requested is if disclosure of the disability takes place . This disclosure decision making process is likely complex and dependent upon multiple factors . Aspects such as workplace culture job duties severity of symptoms individual motivations and characteristics of the communication disorder likely all play a role when weighing the decision to disclose .
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A communication disorder can be classified as a disability under the law. Disclosure of disability is required to receive workplace accommodations. This article summarizes the factors that may influence this disclosure decision. Clinicians can assist individuals in navigating the disclosure process. Implications for future research in this area are discussed.
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S0021992420301155
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Several studies have investigated cognitive communication disorders affecting oral expression skills following TBI but very few have dealt with reading comprehension abilities . The current study aims to measure reading comprehension and speed of reading in adults with uncomplicated and complicated mild traumatic brain injury and to determine which demographic and TBI related variables are predictive of their performance . The performances of three groups of participants were compared on the Chapman Cook Speed of Reading Test . The CCSRT was administered in an acute care setting to 85 hospitalized participants with mild TBI showing traumatic cerebral lesions to 15 hospitalized participants with uncomplicated mild TBI and to 68 adults without TBI . Linear regression analyses were performed to determine which variables among sex age education TBI severity speed of processing skills and site of cerebral lesions significantly predicted CCSRT performances . The control group showed a lower percentage of errors than both TBI groups . On the total score of the CCSRT the uncomplicated and complicated TBI groups performed worse than the control group . Moreover as age and speed of processing skills increased and education decreased the odds of having a lower score on the CCSRT increased . These findings suggest that reading abilities are compromised after mild TBI . Furthermore the CCSRT may be a useful bedside tool for clinicians who work with individuals with mild TBI .
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Mild traumatic brain injury has a significant impact on reading comprehension and speed of reading. No significant difference was found between the complicated and uncomplicated mild TBI groups on acute reading abilities. A younger age and higher level of schooling was associated with better performances on reading. In acute care support should be provided to patients with mild traumatic brain injury when they are required to read.
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S0021992420301167
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Treatments for anomia have demonstrated short and long term efficacy . However individual outcomes can be variable and evidence for treatment generalization is limited . We investigated whether treatment related measures of access to and learning of language namely a responsiveness to cues and b during treatment improvements in naming are good predictors of treatment outcomes . In addition we investigated mechanisms underlying treatment generalization . Ten adults with chronic post stroke aphasia received a phonological treatment for anomia three times a week for five weeks . Naming accuracy of treated and untreated words was assessed pre and post treatment and at four and eight week follow ups . Generalization to an untrained naming task which involved analyses of naming accuracy and speech errors was also assessed speech errors were analyzed according to the Interactive Activation model of word retrieval . Group analyses indicate significant improvements in naming treated compared to untreated words at all timepoints after therapy . Additional analyses showed significant long term improvements in naming untreated words . Initial responsiveness to cueing and early improvement emerged as significant predictors of overall pre to post treatment improvements in naming
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PCA is an efficacious therapy approach but individual outcomes are variable. Generalization may be mediated by a strengthening of lexical phonological connections. Initial cue responsiveness predicts gains in naming treated words after therapy. Early during therapy gains predict outcomes for both treated and untreated words.
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S0021992420301179
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There is a growing pressure to teach foreign languages as early as possible and children with Developmental Language Disorder are not immune from these pressures . However current scholarship lacks crucial insights into how children with DLD respond to L2 learning with minimal exposure . In this paper we report the results of a longitudinal study tracing the development of L1 Russian and English as a Foreign Language skills in a group of learners with DLD . The performance of the DLD group was compared to that of typically developing controls matched for classroom EFL exposure . Proficiency in English and Russian was measured three times . At Time 1 there were no significant differences between groups on the EFL measures but the performance of the typically developing children significantly improved with time and that of the DLD group did not . In the DLD group age of EFL onset was positively related to English receptive vocabulary size . The relation between L1 and L2 proficiency in the DLD group was weaker than in the comparison group . This pattern is probably due to the floor performance of the DLD group in the grammatical domain but may also indicate that the disorder affects cross language transfer in the vulnerable domains .
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Primary school learners with DLD develop foreign language skills very slowly. Children with DLD learn vocabulary faster if they start EFL lessons at an older age. L1 vocabulary predicts EFL vocabulary size in children with TLD and DLD. Children with DLD have less informal exposure to English outside of classroom.
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S0021992420301180
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To determine if people with Parkinsons disease experience dyspnea during speaking . The participants were 11 adults with PD and 22 healthy adults . Participants were asked to recall experiences of breathing discomfort across different speaking contexts and provide ratings of those experiences then they rated the breathing discomfort experienced while performing speaking tasks that were designed to differ in respiratory demands . Participants with PD reported experiencing breathing discomfort during speaking significantly more frequently than did healthy participants . Retrospective ratings did not differ significantly from Post Speaking ratings . Breathing discomfort was experienced by the fewest number of participants with PD for Conversation and Extemporaneous Speaking and by the greatest number for Extended Reading and Long Counting although the magnitude of the ratings generally reflected only Slight discomfort . Breathing discomfort was most frequently described as Individuals with PD are more apt to experience speaking dyspnea than healthy individuals especially when speaking for extended periods or when using long breath groups . Such dyspnea may contribute to a tendency to avoid speaking situations and thereby impair quality of life .
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People with PD frequently experience mild breathing discomfort during speaking. Certain speaking tasks were more apt to elicit sensations of breathing discomfort. Speaking related breathing discomfort can be characterized by different qualities.
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S0021992420301192
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The objective of this work was to verify the efficacy of a treatment based on myofunctional therapy techniques which aimed to improve the tongue strength precision and speed of a ten year old girl with nemaline myopathy and the repercussions of this therapy on her speech intelligibility . NM is a rare congenital muscle disorder that causes extreme muscle weakness especially in the face and neck as well as severe dysarthria and dysphagia although this does not affect the nervous system or cognitive development . This was a single subject experimental study which used an interrupted pre and post treatment time series design and which applied autoregressive integrated moving average predictive models and Holt exponential smoothing . During the treatment phases the participants tongue strength and the rate of speech diadochokinesia and voluntary lingual movements were estimated and the repercussions of the intervention in terms of speech intelligibility were ascertained via an experiment with nave judges . The treatment produced a sustained and significant increase in the maximum strength of the patients tongue which increased from an initial 4 kPa to 11 kPa at the end of the treatment phase . However this was far from the average 58 kPa for age and sex matched normative data . There were no significant changes either in the rates of voluntary lingual mobility or speech diadochokinesia . Speech intelligibility as assessed by nave judges improved from 40 in the pre treatment phase to 67 in the post treatment phase . NM and other rare primary muscle disorders allow us to estimate the effects of severe muscle weakness in people with dysarthria without cognitive impairment or alterations in central nervous system peripheral nervous system or in gap junction . In this case the treatment did not increase the patients lingual and articulatory movement speed but did increase her tongue strength from 5 to 10 of the levels otherwise expected for her age and significantly improved the intelligibility of her speech and communication .
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Nemaline myopathy is a rare disease that allows us to estimate the effects of severe muscle weakness. Speech therapy increased tongue strength and improved the intelligibility patients speech. Results help us to understand the concept of critical weakness of the articulatory muscles.
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S0021992420301209
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This study reports outcomes from a stuttering therapy approach that combines value and awareness based elements from Acceptance and Commitment Therapy with those of stuttering and speech modification interventions . The approach entitled Eighteen adults age 2161 years took part in an A B A multiple case study design . Participants underwent a pre clinic assessment phase followed by 10 h of therapy over four sessions administered by an experienced speech language therapist . Outcome measures examined both psychosocial and behavioral aspects of therapy three six and twelve months post therapy . Most participants chose elements from at least four of the five areas of focus . There was a significant reduction in the impact of stuttering at both 6 and 12 months post therapy with moderate Findings indicate that MIST can be effective in managing adult stuttering . The findings highlight the importance of shared decision making and personal considerations using flexible therapy approaches that integrate stuttering and speech modification interventions with value and awareness based skills . The nature of a multidimensional individualized approach as shown in this study highlights the importance of adjusting the relative weighting of different subcomponents according to each individuals needs and goals . MIST was shown to be efficacious in clinical settings and effective in real life settings . Findings were promising despite a relatively small sample and replication by other SLPs and with larger samples is warranted .
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Identifies outcomes from a new Multidimensional Individualized Stuttering Therapy approach to the management of adult stuttering. Emphasizes the need to consider individual differences when planning treatment. Identifies how this approach can be applied flexibly from client to client. Explains the basis of Acceptance and Commitment Therapy ACT approach to stuttering. Demonstrates the advantages in combining elements from ACT with components from stuttering and speech modification approaches.
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S0021992420301210
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A considerable amount of research has identified inhibition differences including slower inhibition of manual responses in people who stutter . Recent investigations have failed to link slowed motor inhibition with overt stuttering severity . This study investigated the potential relationship between slowed manual response inhibition and the negative impact of stuttering upon individual lives of adults who stutter . Thirty four adults matched by nonverbal IQ completed a manual stop signal task and provided a conversational speech sample . Motor inhibition latency for AWS and AWNS were compared . For AWS motor inhibition latency was compared to the four subsections of the Overall Assessment of the Speakers Experience with Stuttering . Similar to previous studies AWS were significantly slower to inhibit inaccurate manual responses than AWNS . Quality of Life subtest of the OASES was found to significantly predict inhibition latency . These data replicate findings that indicate that AWS exhibit slower manual inhibition latency and suggest that these inhibition differences may be associated with an individuals negative experience with stuttering rather than stuttering severity .
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Adults who stutter had slower manual inhibition compared to non stuttering adults. Negative experiences with stuttering predicted slower inhibition. No relationship was found between stuttering severity and inhibition function. Adverse impact of stuttering may share a bidirectional relationship with inhibition.
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S0021992420301222
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It has been suggested that factors such as auditory perception oral motor skills phonological awareness and working memory are all associated with speech production problems in children with speech sound disorder and developmental language disorder . However it remains unclear whether the severity of the speech production problems in these children can be explained by an interaction among the aforementioned factors . The aim of this study was to determine which of these four factors best explain the severity of the speech production problems in children with SSD and DLD and whether an interaction between factors occurs . Forty one children with SSD and DLD between 5 and 5 11 years old were selected . The number of phonological process errors was used as a measure of the severity of the speech production problems . The association between the number of phonological process errors and performance in auditory perception oral motor skills phonological awareness and working memory along with the severity of the DLD was explored using univariate and multivariate regression models . The results showed that the number of phonological process errors was largely explained by working memory and phonological awareness . An interaction between these two factors was also found . This means that working memory and phonological awareness interact to have an effect on the number of phonological process errors that is more than the sum of their parts .
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Phonological awareness is associated with the severity of speech production problems. The severity of the developmental language disorder is associated with the severity of speech production problems. The severity of speech production problems is mainly explained by working memory.
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S0022311519300832
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The European Mini Plate Irradiation Experiment aims to test the in pile behavior of various ZrN coated UMo powder batches produced using different technological processes . UMo particles are typical core shell systems taking advantages of a dense fissile material UMo with a coated ZrN layer acting as a diffusion barrier . The U 7Mo kernels were produced by centrifugal or rotating electrode atomization processes and the ZrN coating was performed by physical vapor deposition or atomic layer deposition processes . A total of ten batches of UMo powders were examined in the as obtained state
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Ten selected UMo ZrN powders for the EMPIrE in pile tests have been examined. UMo ZrN powder particles were examined in the as produced state. Size and shape parameters were determined by means of digital image processing. Classification of the batches is presented as radar chart. Thickness roughness and grain structure of the ZrN films were examined.
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S0022311519301205
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This paper presents a numerical model developed to reproduce the behaviour of French simplified Bituminized Waste Products during a leaching test . The model is calibrated on experimental data sets . BWP were mainly produced during industrial reprocessing of nuclear spent fuel and are classified as low or intermediate activity long lived radioactive waste . Geological disposal is the reference solution for intermediate level long lived BWP . Under geological disposal facility conditions and after a long period of time BWP will undergo water re saturation from the host rock . A chemo hydro mechanical numerical model has been implemented with a finite element scheme to model BWP behaviour under such conditions . The constitutive model takes into account the impact of dissolution permeation diffusion and osmosis . Original evolution laws of diffusion coefficient and permeability as a function of the porosity are proposed . Specific mechanical model is proposed including Mori Tanaka homogenization law . To simulate the hydration of the material an original and simple method is proposed avoiding costly two phase flow resolution and complex calibration of the related parameters . This model was mainly used to reproduce the evolution of the amount of both water absorbed and salt leached by the sample during unconfined water up taking tests . The calibration is based on experimental data obtained on French simplified BWP containing one highly soluble salt . Water uptake could generate swelling mainly due to osmosis .
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Main indicators studied are the amount of salt leached water absorbed and the swelling. The trends in indicators are reproduced by a Chemo Hydro Mechanical numerical model.
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S0022311519303514
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We have succeeded in observing Fe ion beam induced nanostructural change of MA956 oxide dispersion strengthened steel using anomalous small angle X ray scattering diffractometry . The ASAXS curve shows a power law scattering that follows the Porods law and an overlapped shoulder peak at the magnitude of scattering vector
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Our ASAXS enables to observe nanostructural change in steel by Fe ion irradiation. ASAXS intensity of Cr poor scatterer was doubled by the irradiation. In contrast the irradiation didnt change the scattering of precipitates at all. Irradiation induces neither growth suppression nor interface modification of .
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S0022311519303551
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A self consistent thermodynamic description of YH binary system has been derived using the CALPHAD method with the aid of first principles calculations and applied in the fabrication of crack free bulk ZrY hydride neutron moderator . The enthalpies of formation of the end members calculated by first principles were adopted for the thermodynamic assessment . Only four model parameters were needed and optimized with the available experimental data from literature . The calculated phase equilibria and thermodynamic data agree well with experimental data . YZrH ternary system was constructed by extrapolation of three binary sub systems . According to the thermodynamic calculation results the hydrogenation of ZrY alloys was divided into three stages isothermal hydriding isobaric hydriding and terminal hydriding . By carefully controlling the temperature and hydrogen pressure the transformation from metal to hydride of yttrium and zirconium can be separated and carried out in different stages so that the cracks formation during hydrogenation was successfully inhibited . With addition of yttrium the stress induced by the martensitic transformation from to zirconium hydride would be relaxed . As a result hydride embrittlement can be mitigated and the bulk ZrY hydrides without micro cracks can be fabricated .
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A self consistent thermodynamic description of YH and YZrH system was derived. The ab initio enthalpies of formation were adopted for thermodynamic assessment. A three stage hydriding process was established based on thermodynamic calculation. The martensitic transformation from to zirconium hydride is inhibited by yttrium. Zirconium hydride without micro cracks can be fabricated with addition of yttrium.
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S0022311519304258
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Performance assessment of geological nuclear waste repositories entails modeling of the long term evolution of the aqueous alterations of the fractured nuclear glass block because the time scales under consideration are of several thousands of years and hence beyond the range of any direct experimental perspectives . In this study our objective is to bridge the gap between the reservoir scale flow and transport simulations and the micron scale modeling of the glass water interfacial processes by providing quantitative evaluation of the aqueous alteration of glass at the block scale . In particular calculations of the equivalent diffusive hydraulic and alteration kinetics properties and reactive transport simulations are discussed . Prior to performing reactive transport modeling at the scale of the glass canister the preferred upscaling techniques were first applied to a synthetic fracture network system with ends to compare the results of the borosilicate glass alteration with the discrete fracture modeling and the equivalent porous medium approach . The evolution of the altered glass obtained from reactive transport modeling applied to several realizations of the equivalent fracture network tessellation was compared to the experimental data of the aqueous alteration test of a nonradioactive full scale SON68 glass canister . The proposed model agrees with the experimental data and offers for the first time an opportunity to better understand the impact of fracturing as the convection due to the radioactivity acting as a heating source on the corrosion of nuclear glass .
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Reactive transport is used to assess the corrosion of nuclear fractured glass blocks. Techniques to calculate the reactive transport parameters are proposed and validated. Modeling results agree with the results of a long term aqueous alteration experiment.
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S0022311519306531
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Dispersion strengthened tungsten materials represent a new class of W based materials to be investigated for use as plasma facing component in nuclear fusion reactors . However the retention and permeation characteristics of these materials under low energy deuterium irradiation need to be elucidated before the efficacy of these materials can be judged . Due to possible deep penetration of D in W depth profile techniques such as glow discharge optical emission spectroscopy are needed to probe D concentrations many microns beneath the material surface . In this study the D retention behavior of W materials containing 110wt TaC TiC or ZrC are investigated with GD OES . After exposure to a 510
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Behavior of dispersion strengthened W under D irradiation examined. GD OES used to study D depth profiles in TaC TiC ZrC doped W. Specimen microstructural and compositional effects on D retention and diffusion.
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S0022311519306622
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Tungsten is the prime candidate material for divertor applications in future nuclear reactors . In the present work a spatially dependent cluster dynamics model is developed to investigate and understand the microstructure evolution of tungsten under low energy helium implantation and neutron irradiation varying over bulk length scales of millimetres and irradiation time scales of hours . The diffusion of helium helium clusters and their trapping at neutron induced defects is simulated along the tungsten monoblock depth . The temperature gradient resulting from a steady state heat load of 10MWm
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Synergistic neutron and helium irradiation under a temperature gradient in W monoblock is simulated for longer time scales. Pronounce formation of helium vacancy based defects is observed in the sub surface region of the monoblock. Mobility based influence of the helium clusters on the defect evolution and diffusion length scales is investigated. Extended diffusion of helium in the bulk monoblock is noticed. A measure of the stored energy is obtained from the defect concentration in the monoblock.
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S0022311519306671
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The accurate prediction of tensile properties has great importance for the service life assessment and alloy design of RAFM steels . In order to overcome the limitation of traditional physical metallurgical models machine learning algorithm was used to establish universal models for the prediction of RAFM steels yield strength and total elongation . A database with a wide range of compositions and treatment processes of RAFM steels was first established . Then feature engineering methods were used to select the highly correlated features . With the reasonable selection of machine learning algorithm and test training set partitioning strategy random forests regressors were trained by the selected features . The prediction results proved that compared with traditional physical metallurgical models the feature engineering guided random forests regressors had advantages of accuracy and universality for the prediction of RAFM steels yield strength and total elongation . And the calculated process window for the balance of strength and plasticity could provide guidance for the further design and development of RAFM steels .
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A tensile property database of RAFM steels was established. High correlated features were selected to train the random forests regressors. Both yield strength and total elongation of RAFM steels were predicted. The process window of RAFM steels for reasonable tensile property was calculated.
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S0022311519307287
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The effective diffusion theory which is generally used in the modelling of base irradiation of nuclear fuel can not predict the intra granular fission gas release during post irradiation annealing tests . From this discrepancy between experiments and usual theory several alternative scenarios emerged . The purpose of this work is to model these scenarios as mechanistically as possible and to distinguish those that could really explain the observations . The difficulty is that the fission gas bubbles in irradiated UO
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Fission gas release during post irradiation annealing of UO. is analyzed. Directed movement of pressurized intra granular gas bubbles in a vacancy concentration gradient is modelled. Random movement of these intra granular bubbles via surface diffusion is also incorporated. The FGR solely due to intra granular bubble migration due to these mechanisms is quite insignificant compared to the experimental value.
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S0022311519307627
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Reduced activation ferritic martensitic steels such as Eurofer97 and F82H which have been widely studied contain a small quantity of Ta to improve their mechanical properties by fine MX precipitates . In this study the effect of addition of Ti as well as Ta on the strength and impact toughness of 9Cr 1W RAFM steel was investigated . Ta and Ti added RAFM steel shows a superior balance of strength and impact toughness compared to Ta added RAFM which is similar to the composition of Eurofer97 . In particular the ductile brittle transition temperature of TaTi RAFM decreased markedly . M
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Ta and Ti added RAFM steel TaTi RAFM showed dramatic improvement in DBTT without compromising with strength. The improvement of DBTT in TaTi RAFM originates from refinement of M23C6 carbides at which brittle cracks initiate. The improvement of DBTT was well explained by the modified Griffith model using the maximum size of the M23C6 carbides.
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S002231151930769X
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The effects of temperature and pH on the electrochemical properties of Alloy 600 were studied in oxygenated borate buffer solutions by the measurements of open circuit potential anodic potentiostatic polarization Mott Schottky analysis and electrochemical impedance spectroscopy . At each temperature and pH the stabilized anodic passive current density was independent of the formation potential and the slope of the MS plot for the passive film formed at 0.3 V
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Passive films formed on Alloy 600 up to 300 C in oxygenated borate buffer solution show n type semiconductor character. With increasing temperature passive current density and defect density increased impedance modulus decreased obviously. With increasing pH passive current density decreased and the absolute value of impedance increased slightly. Concentration of cation interstitials is much higher than that of anion vacancies. Deteriorative effect of elevated temperature on alloy corrosion resistance is more significant than the effect of pH.
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S0022311519308049
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In the framework of JAEA CEA collaboration experimental studies have been conducted for estimating the material characteristics of corium debris representative of the Fukushima Daiichi nuclear damaged plants . A test has been performed in the VULCANO facility in CEA Cadarache to simulate the concrete corium interaction with prototypic corium and concrete of Fukushima Daiichi 1F1 Nuclear Plants . This paper presents the Post Test Analyses on 9 samples representative of the CCI during this test in the corium pool in the crusts and at the vertical and horizontal interfaces with the concrete . Analyses have been performed by SEM EDS X Ray Diffraction complete dissolution and ICP micro hardness measurements of the main phases . The pool is very porous its composition is homogeneous but metallic blocks have been observed at the interfaces . The major phases encountered are uranium rich and zirconium rich oxides forming nodules from micrometers to millimeters size chromium iron rich precipitates of several micrometers metallic FeNi droplets and chromium silicon rich filaments in a matrix likely vitreous rich in concrete elements Si Al Ca but containing up to 12 cations . The matrix is the softer oxide phase when the Cr rich precipitates are the harder . The analyses are consistent with the estimated macroscopic ablation ratio but do not still explain the important axial ablation observed for this specific basaltic concrete . The different phases formation distribution and solidification path are discussed . First comparisons are proposed with the former CCI tests with European concretes . These results give helpful insights for the future dismantling of the plant and for a deeper understanding of the CCI process for basaltic concrete .
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Characterization of reaction between synthetic corium and basalt based concrete. Pool consists of corium nodules and spinel phases dispersed in silicon rich matrix. Metallic IronNickel alloys were identified at bottom horizontal interface. Phases and ablation profile are compared to previous tests with European concrete.
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S0022311519308402
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A layer of Cr coating on the inner surface of HT9 cladding is a promising barrier to hinder fuel and cladding chemical interaction in sodum coolded fast reactors . Cr barriers obtained with various current densities and electrolyte temperatures used for the electrodeposition of HT9 disks were investigated for thickness Vickers hardness and the existence and length of microcracks . The crack free Cr barrier electrodeposited at 1.6 A cm
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Fuel and cladding chemical interaction FCCI on inner surface of HT9 cladding tubes were mitigated by Cr coating layer. A Cr barrier with sound microstructure was successfully coated using electrodeposition process. Burst and tensile mechanical tests verified the excellent adhesion and ductile characteristics of Cr barriers.
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S002231151930844X
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The thermoelectric materials that work in radioisotope thermoelectric generators or space reactor power sources will be exposed to neutron irradiation and gamma irradiation for a long time . Herein the influences of neutron irradiation doses between 10
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Neutron irradiation with dose of 10. n cm. 10. n cm. induces defects in SiGe. Electrical conductivity decreases to 0.014 0.14 of the pristine value after 10. n cm. neutron irradiation. Themoelectric properties can be recovered after heat treatment. Neutron induced damage is worse in n type SiGe than in p type SiGe. 10. Gy gamma irradiation has no influence on themoelectric properties of SiGe.
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S0022311519308797
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By combining experimental observations on Gd doped fuel with a theoretical understanding the variation in thermal conductivity with Gd concentration and accommodation mechanism has been modelled . Four types of Gd accommodation mechanisms have been studied . In UO
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Effect of Gadolinium accommodation mechanism on thermal conductivity of Gd doped UO. Effect of Gadolinium concentration on thermal conductivity of Gd doped UO. Less phonon scattering by defect clusters than by isolated defects. Gadolinium accommodated by forming defect clusters Gd. U. in UO. with excess oxygen.
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S0022311519308827
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Interest in U Zr metallic nuclear fuels has been on the rise but sparsity in the available diffusion data continues to hinder efforts to model irradiation behaviors like constituent redistribution . In the current work we develop a quantitative phase field model for the influential and phases of U Zr and use it to reexamine data from a published diffusion couple experiment . We optimize the two phases kinetic parameters and use annealing simulations to show that the optimized model produces more accurate predictions than those obtained using the diffusion parameters currently employed by constituent redistribution models . We then demonstrate how to minimize the impact of user defined model parameters such that the parameters based on experimental data dominate the models response . Sensitivity analysis studies confirmed that the phases kinetic parameters are more influential than the interface energy for this type of problem and phase kinetics were found to be more impactful than phase kinetics . This observation is believed to be related to differences in phases solubility ranges and diffusion limiting behaviors . These findings and the interpretive modeling technique employed in the current work will increase the efficiency of the data collection efforts necessary to reduce uncertainties in U Zr diffusion parameters expediting further fuel development .
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The diffusion behaviors of U Zr phases exhibit strong composition dependencies. Additional experiments are needed to reduce uncertainty in U Zr interdiffusivities. User defined phase field parameters can be selected to maximize model performance. Data analysis using mechanistic models improves accuracy over empirical smoothing.
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S0022311519308840
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Lithium aluminate has attracted researchers interests due to its wide applications . The structural electronic optical lattice phonon thermodynamic and thermo conductive properties of LiAlO
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Electronic lattice phonon thermodynamic and thermo conductive properties of LiAlO. with. Li isotope substitution. Li isotope substitution makes differences on its phonon dynamics thermodynamics and Infrared Raman spectra. This is the first approach to calculate the thermal conductivity of LiAlO. . The method can be applied to other materials. This is the first theoretical study on the effects of. Li isotope substitution on the properties of LiAlO. material. Results are very useful for further to exploring the. H production and transport through LiAlO. ceramic pellets.
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S0022311519308864
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Oxide Dispersion Strengthened steels are considered as promising materials for structural components of advanced fusion and fission reactors . Its performance is largely determined by particle size and stability of the dispersed oxide nano particles which forms during high temperature extrusion after dissolution of yttria in Fe during mechanical alloying . As the reactor structural materials are exposed to high neutron flux study of irradiation stability of these particles is very important . In order to study irradiation stability of oxide particles in ODS alloy two different ODS alloys of composition Fe 0.2Ti 0.3Y
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5MeV Ni. ion beam irradiated ODS alloys of composition Fe 0.2Ti 0.3Y. and Fe14Cr 0.2Ti 0.3Y. were studied at 600 and 700C. At a dose of 40 dpa at sample surface refinement of particle size takes place at 700C in both the alloys. Cr plays a significant role in further tailoring the particle size to a very narrow zone of finer size upon irradiation. Strong effect of Cr in particle dissolution could be because of the initial finer sized particles present in the Cr added alloy or the less displacement energy of the Cr rich shell around the particles providing a driving force for particle mass loss.
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S0022311519308979
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Interatomic potentials for tungstenvanadium and tungstenmolybdenum binary systems have been developed based on FinnisSinclair formalism . The potentials are based on an accurate previously developed potential of pure W. Potential parameters of VV MoMo WV and WMo were determined by fitting to a large database of experimental data as well as first principle calculations . These potentials were able to describe various fundamental physical properties of pure V and Mo such as a lattice constant cohesive energy elastic constants bulk modulus vacancy and self interstitial atom formation energies stacking fault energies and a relative stability of 100 and 111 interstitial dislocation loops . Other fundamental properties of the potentials described included alloy behaviours such as the formation energies of substitutional solute atoms binding energies between solute atoms and point defects formation energies and lattice constants of artificial ordered alloys . These results are in reasonable agreement with experimental or first principle results . Based on these results the developed potentials are suitable for studying point defect properties and can be further used to explore displacement cascade simulations .
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Interatomic potentials for WV and WMo binary systems based on FS formalism have been developed. The developed potentials are applicable for studying the point defect properties and displacement cascade simulations. These potentials also provide a basis for fitting the interatomic potentials of tungsten based multi element alloys.
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S0022311519309092
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The effects of alpha radiation on cementitious systems used for nuclear waste encapsulation and the subsequent physico chemical properties have been subject to limited investigation comparative to the effects of gamma and neutron irradiations . This paper outlines an assessment of the impact of PuO
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PuO. was encapsulated in BFS PFA blended cements used for nuclear waste disposal. Cellulose was added to the systems to investigate the effects of organics. No large scale microstructural defects were observed and good physical contact between the PuO. and grout was seen. Changes to the phase assemblage were noted in BFS containing grouts. Radiolytic gas evolution was consistent with expectations with increased values observed for samples containing cellulose.
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S0022311519309687
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This study investigates the effect of a built up sequence on the hot cracking resistivity of dissimilar clads . Dissimilar clads of Inconel 52 and austenitic stainless steel 308L were produced using submerged arc welding of the carbon steel . Hot cracking occurred near the fusion boundary when the STS 308L was cladded to the buffer layer of Inconel 52 . Causative factors were identified as the wide transition zone in the interface between the dissimilar clads and the eutectic type Laves phase having a high level of S and P contents and a continuous geometry of thin films formed along the grain boundary . Hot cracks did not appear when Inconel 52 was cladded to the buffer layer of 308L stainless steel . Hot cracking resistivity was significantly improved by forming ferrite in the interfacial boundary for the Inconel 52 STS 308L clad .
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Hot cracking depends on the built up sequence of Inconel 52 and STS 308L overlay. Hot cracks occurred in a wide transition zone having continuous eutectic Laves. The ferrites remaining in the interdendritic region improved hot cracking resistance. Inconel 52 STS 308L clad had fast solidification and a narrow transition zone.
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S0022311519309845
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We compare two full field approaches a crystal plasticity finite element method and crystal plasticity fast Fourier transform based method for a specific crystal plasticity law introduced for neutron irradiated austenitic stainless steel SA304L currently used in nuclear reactor vessel internals . This particular law is employed to identify and quantify possible advantages and drawbacks of the two approaches when used in the large scale simulations to predict the effect of irradiation damage in stainless steel microstructures . A comparison is performed in a polycrystalline context for different periodic Voronoi microstructures deformed under tension . Special emphasis is put on studying the performance of the two approaches in terms of mesh convergence analysis using aggregate models with different spatial discretizations . In the CP FEM approach the performance of linear as well as quadratic tetrahedral meshes is investigated . A similar performance between the CP FEM and CP FFT methods is demonstrated in a smaller 2 grain aggregate . However a slower mesh convergence is observed for the CP FEM method when comparing tensile responses of a larger 100 grain polycrystal . A drop in the convergence rate is much more pronounced on linear than on quadratic tetrahedral meshes . As a consequence largest grain boundary stresses are shown to be overestimated with the linear mesh CP FEM approach thus raising a concern of possible over conservatism employed in the CP FEM prediction of crack initiation in irradiated stainless steels . On the contrary the mesh convergence of the CP FFT approach is found to be practically independent of the applied macroscopic strain and also aggregate size . Therefore for such steels the CP FFT approach seems to be better justified .
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CP FEM and CP FFT are compared when employed to neutron irradiated stainless steel. Comparison is performed for periodic Voronoi microstructures deformed under tension. Linear quadratic tetrahedral elements are used in CP FEM and regular grid in CP FFT. Spatial discretization convergence analysis is applied on 2 and 100 grain models. CP FFT is found superior to CP FEM in larger and plastically strained aggregates
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S0022311519309882
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Oxide dispersion strengthened steels are promising accident tolerant fuel cladding alternatives because of their excellent oxidation resistance and mechanical properties at high temperatures . Coupons of 12Cr6Al ODS steel with an electron beam weld line were irradiated with 6.4MeV Fe
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EB welded 12Cr6Al ODS steel was irradiated at 300C to 2.6 7.9 and 13.0 dpa. Oxide particles in ODS base metal were stable at 300C up to 13.0 dpa. Higher irradiation hardening in EB weld line than base metal. Evolution of loop size and number density in ODS base metal and EB weld line. Comparison between neutron and ion irradiation at fixed condition 300C 2.6 dpa.
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S0022311519309924
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Protective coatings of Zr based claddings have been proposed for the development of Accident Tolerant nuclear Fuel . Coatings forming stable oxides at high temperature such as MAX phases are attractive candidates for these applications . In this study CrAlC coatings were deposited on coupons of Zr based alloy by High Power Impulse Magnetron Sputtering . Cr
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Amorphous CrAlC and nanocrystalline Cr. AlC coatings were deposited by HiPIMS PVD. CrAlC and Cr. AlC coatings delay the oxidation of Zr alloys at high temperatures. Zr alloy protection is effective thanks to the formation of a dense oxide scale. Coating and Zr alloy elements interdiffuse at temperatures above 1000C.
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S0022311519310104
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This research demonstrated the first time that synchrotron X ray micro computed tomography was utilized to analyze the three dimensional morphology of the microstructure of irradiated nuclear fuel . Both absorption contrast and propagation based phase contrast enhanced CT techniques were evaluated . Porosity and phase region volumes were determined in neutron irradiated uranium 10wt zirconium using propagation based phase contrast enhanced CT . Volumes were calculated using image processing software and algorithms with the porosity volume subsequently compared to the ASTM
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First synchrotron CT characterization of neutron irradiated U10Zr fuel. Synchrotron CT revealed the presence of three distinct phase regions and pores. Volume fraction assessment revealed that 7.2 of the U10Zr fuel specimen is porous. Porosity distribution is further classified on basis of pore volume and morphology. Localized microscopic fuel swelling for the intermediate redistribution concentric zone is 7.7 .
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S0022311519310177
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H bulk diffusion in Excel was measured using the Laser Induce Breakdown Spectrometry technique in 469 660K temperature range for the first time . D temperature dependence obeys the Arrhenius law with activation energy Q kJ mol and D
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H diffusion in Excel was measured for the first time in 466660K temperature range. The Arrhenius law is obey with Q 30kJ mol D. 3x10. s. Diffusion parameters are close to the Zr. Nb ones. LIBS proves to be a suitable and improving technique to measure H diffusion in metals.
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S0022311519310311
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FeCrAl oxide dispersion strengthened steel is one of the most promising candidate cladding materials of generation IV nuclear reactors because of its excellent resistance to not only corrosion but also creep and irradiation due to the ultrahigh density nanometer scale oxides . Effects of the contents of Al Zr and Ti on the crystal and metal oxide interface structures of the particles in Fe15Cr3.7Al2W0.1Ti0.6Zr0.35Y
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Oxides in Fe15Cr2W0.35Y. ODS steels with Al Zr and Ti were studied by HRTEM. Crystal interface structures of 175 oxides were identified for 3.7Al0.1Ti0.6Zr. Crystal interface structures of 213 oxides were identified for 3.8Al0.12Ti0.5Zr. Proportions of various types of oxides were determined according to HRTEM results. The content ratios of Al Zr Ti cause the polymorphic transition of complex oxides.
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S0022311519310402
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We model the elastic field near the void using a Modified Molecular Static method . Results show that the atom displacements near nanovoids significantly differ for various crystallographic directions in bcc metals . Using some results of these calculations we estimate the void growth rates following various directions basing on recently obtained equations of vacancy diffusion under strain . This growth rate anisotropy helps to explain the change in shape observed for many voids .
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Shifting rate equations of void surface elements following various crystallographic directions. The atom displacements in the vicinity of the nanovoids in bcc iron. The shift rate of the void surface elements following various crystallographic directions. It is shown that asymmetric elastic field decrease the shift rate of above elements in 100 direction. Effect should change the shape of the initially spherical void to the cuboid type.
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S0022311519310517
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Corrosion of zirconium claddings is one of the key properties that must be considered when designing new zirconium alloys . Tetragonal phase is formed on the zirconium matrix during high temperature corrosion and is mainly stabilized near the metal oxide interface . This phase has a tremendous influence on the corrosion behavior of zirconium alloys . T ZrO
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Stress in m ZrO. is mostly released after removing the zirconium matrix. T ZrO. phase formed on zirconium alloys is still stabilized even after removing the matrix. Lattice distortion introduced by large content of vacancies is proposed to be important stabilizer. The layer thickness of t ZrO. phase increases with time in the pre transition stage and drops down after transition. Micro distribution of interfacial t ZrO. is related to the interfacial morphologies.
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S0022311519310736
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Because of their hexagonal close packed structure and easy prismatic slip the tensile properties of Zirconium based alloys show strong texture dependence and hence anisotropy . The type of texture microstructure and hence the mechanical properties depend upon the sequence of manufacturing process followed in fabrication of components such as pressure tubes in pressurized heavy water type reactors . Due to small wall thickness of the pressure tubes designing and machining of specimens in all the three directions especially in the radial direction is a challenge and this explains the reason for scarcity of work in this area in research literature . In this work different types of specimens have been machined from transverse longitudinal and radial orientations of the Zr2.5 Nb Indian PT following a novel design in order to study the anisotropy in the plastic deformation and hardening properties . In addition shear specimens have been extracted from longitudinal transverse plane to study the plastic deformation in shear . Tests on tensile and shear specimens have been carried out at room temperature 100 200 and 300C respectively . Using the experimental data the parameters of Hills anisotropic yield function have been evaluated . In addition to evaluating the parameters at initial yield point the nature of variation of these parameters with equivalent plastic strain has also been established . This new material model where the anisotropic parameters evolve with plastic strain shall be useful for design and integrity assessment of the pressure tubes for different types of postulated loading conditions .
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Zr2.5 Nb pressure tubes develop a texture during extrusion and pilgering processes leading to anisotropy in properties. Special geometries of tensile and shear specimens are designed to facilitate their extraction from different orientations. An algorithm has been developed for evaluating Hills parameters required for modeling anisotropy at different temperatures. Yield and ultimate tensile strength values for transverse specimens are higher compared to those of other orientations. Anisotropic parameter G is greater than F and H indicating shifting of Hills yield surface towards transverse orientation.
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S0022311519310748
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Irradiations were performed with 1.5MeV protons to 0.6 dpa at 40150C on additively manufactured 304L stainless steel and the changes in microstructure and mechanical behavior after irradiation were compared to wrought 304L stainless steel . All microstructural and hardness results after irradiation suggest the samples evolve toward a similar state despite significant differences in the unirradiated microstructures and hardness values . A TEM and nanoindentation based investigation of before and after proton irradiation at 40150C is presented . Results are interpreted in terms of initial dislocation content dislocation structures and microstructural and chemical homogeneity .
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Microstructures evolve similarly for irradiated AM and wrought 304L. Nanohardness values are similar for all samples after irradiation. Proton irradiation of AM and wrought 304L
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S0022311519310797
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The HICU experiment was performed in the High Flux Reactor in Petten NL in order to irradiate candidate tritium breeder materials in a fusion relevant environment . The presented work focuses on the post irradiation examination of the irradiated lithium orthosilicate based breeder pebbles . The pebble samples showed three different contents of Li 6 and were irradiated at two different temperatures and in mechanically constrained and unconstrained state . In this particular publication the influences of the irradiation conditions on the pebble morphology microstructure porosity and mechanical strength are addressed .
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HICU PIE of neutron irradiated Li. SiO. based ceramic breeder pebbles. The material properties significantly depend on the irradiation temperature. An enrichment in. Li does not deteriorate the pebbles properties.
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S0022311519310803
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The former EU reference lithium orthosilicate based breeder pebbles were exposed to neutron irradiation in the HICU experiment to test their stability and tritium release properties under DEMO relevant conditions . The samples varying by three different Li 6 contents were exposed to irradiation at two different temperatures and the pebbles were either pre compacted or not . This second part of the post irradiation examination is focussing on the tritium release behaviour of the ceramic breeder pebbles .
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HICU PIE of neutron irradiated Li. SiO. based ceramic breeder pebbles. The tritium release behaviour is strongly influenced by the irradiation temperature. Tritium is released in a multi staged process as HTO HT or corresponding fragments.
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S002231151931092X
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An accelerated Monte Carlo method for the calculation of the sink strengths of absorbing surfaces for particles in crystals of the cubic system has been suggested . On its basis several algorithms have been developed which allow one to calculate the sink strengths either without any systematic inaccuracy or with its low and controlled magnitude . These algorithms have been tested by calculating the sink strengths of absorbing surfaces of different geometry for particles in a crystal with BCC lattice . The use of the developed algorithms accelerates the calculations for low volume fractions of absorbers by orders of magnitude .
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A new method allows accelerating sink strengths calculations by orders of magnitude. This method takes full account of the discreteness of the crystal lattice. Systematic inaccuracy is absent or has low and controlled magnitude. Sink strengths are calculated for absorbers of various geometry in a bcc crystal.
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S0022311519311067
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As fretting wear has become one of the main failure mode of Alloy 690 tube in steam generators and is significantly affected by normal force and displacement the fretting wear behavior of Alloy 690 with different normal force and displacement is studied in high temperature pressurized water . The coefficient of friction wear volume and maximum wear depth decrease with the increasing of the normal force while they increase with the increasing of displacement . In addition the wear mechanism and wear damage are also significantly affected by the applied normal force and displacement . Wear coefficient and energy wear coefficient are calculated respectively . Energy wear coefficient may be a more precise parameter than wear coefficient to describe the fretting wear process .
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Fretting wear between Alloy 690 and 405 SS with 1.0810. cycles is studied in HTP water. Coefficient of friction and wear volume change significantly under different normal force and displacement. Wear mechanism and wear damages are significantly affected by the applied normal force and displacement. Both wear coefficient and energy wear coefficient are calculated.
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S0022311519311134
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FeCrAl oxide dispersion strengthened steel is one of the most promising candidate cladding materials of generation IV nuclear fission reactors because of its excellent resistance to not only corrosion but also creep and irradiation due to the ultrahigh density nanometer scale oxides . Crystal and metal oxide interface structures of the nanoparticles in FeCrAl ODS steel with Hf addition i.e . Fe15Cr2W0.1Ti4Al0.6Hf0.35Y
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Crystal interface structures of 153 oxides in FeCrAl ODS steel were characterized. Proportions of various types of oxides were determined according to HRTEM results. Crystallographic orientation correlations of the oxides matrix were determined. Minor addition of Hf Ti prompts significant formation of YHfO YTiO oxides.
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S0022311519311328
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When stainless steels are exposed to high irradiation dose a fraction of Frank loops will unfault and transform into perfect loops . After unfaulting perfect loops can glide and impinge into other loops to form dislocation networks and dislocation networks will act as sinks for point defects and solute elements . Besides unfaulting will influence the extent of irradiation hardening as well . Based on previous theories the size of Frank loops was considered to be a key factor in unfaulting . To better understand the unfaulting process 316L stainless steel model alloy was irradiated to 5dpa at 350C 400C and 450C by 3MeV Ni ions . Method was developed to quantitatively compare the size and density between Frank loops and perfect loops through relrod and weak beam dark field techniques . Results showed that unfaulting barely occurred at 350C but was distinct at 400C and 450C . The majority of perfect loops were in the size range of 816nmat 400C and were in the size range of 1220nmat 450C . The existence of a critical loop size for unfaulting was not supported by our results . Moreover by our results the energy of Frank loops does not play a decisive role in unfaulting and the simple approximation of geometric constraint in the rate theory to calculate unfaulting diameter needs to be revisited . Irradiation hardening was also analyzed by nano indention . It was found that loop unfaulting played an important role in the hardening decrease from 350C to 450C .
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Method was developed for size comparison between Frank loops and perfect loops. Unfaulting barely occurred at 350C but was distinct at 400C and 450C. A critical size of loop unfaulting did not exist. The energy of the stacking faults did not play a decisive role in unfaulting.
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S002231151931164X
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The C doped modified layer on uranium surface was prepared by pulsed laser irradiating in methane atmosphere . The microstructure of the obtained layer was characterised by X ray diffraction Auger electron spectroscopy and X ray photoelectron spectroscopy . The results show that the obtained layer is a composite layer with a gradual transition structure from UO
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C doped modified layer with C concentration above 40at on uranium surface was prepared by pulsed laser irradiating. The layer is a composite layer with a gradual transition structure from surface to interior. UC. is more resistant to oxidation than UC. UC under oxygen exposure. Free carbon is distributed in the surface layer of modified layer and also formed after oxidation at RT. C doped modified layer improved the corrosion resistance of metallic uranium.
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S0022311519311663
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Grain boundary embrittlement of reactor pressure vessel steel occurs at the long term operation through the radiation enhanced segregation of impurities . All the known techniques of studying the GB segregation have their advantages and disadvantages and complete information can be obtained only through a comprehensive analysis by different methods .
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Grain boundary segregation in RPV steels is studied by APT AES and fractography. P Ni Mn and Si concentration in grain boundaries increases with fluence increase. The higher is the bulk Ni and Mn content the higher is Ni Mn and P segregation. Co segregation of P and Ni Mn Si in grain boundaries occurs under irradiation. Fraction of brittle intergranular fracture correlates with P segregation level.
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S0022311519312139
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The nucleation of helium bubbles in the early aging stage of tritium storage materials will have an important influence on the bubble growth behavior in the whole of aging . Herein the nucleation of helium bubbles was adjusted by environment temperature at the first 15 days immediately after preparation of polycrystalline titanium tritide films . The influence of the environment temperature on the nucleation of helium bubbles were studied by X ray diffraction positron annihilation spectroscopy thermal helium desorption spectroscopy and scanning transmission electron microscopy . Results demonstrate that the helium bubble nucleation is significantly affected by the environment temperature of60C 20C and 120C . The higher the environment temperature the lower number density of helium bubble in the titanium tritide films . The helium bubble nucleation mechanism is strongly correlated to the helium atom diffusion coefficient that is controlled by the environment temperature . During the following aging the rate of helium atoms captured by a single helium bubble increases in titanium tritides with low number density bubbles which accelerates the growth of helium bubbles in the matrix . However the low number density bubbles also decrease the capture probability of free helium atoms by helium bubbles resulting in the increase of helium atoms diffusing to infinite size defects such as grain boundaries macroscopically and accelerating the evolution of helium in titanium tritides .
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Helium bubble evolution in titanium tritide was studied by XRD PAS THDS and STEM. Helium bubble growth is affected by nucleation mechanism during the early aging. Helium bubble nucleation can be regulated by the storing environment temperature. Helium bubble evolution is strongly correlated to initial density of helium bubble. High temperature storing would accelerate helium bubble growth in titanium tritide.
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S0022311519312279
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Many tools such as mass spectrometry X ray diffraction X ray fluorescence ion chromatography etc . are currently available to scientists investigating interdicted nuclear material . These tools provide an analysis of physical chemical or isotopic characteristics of the seized material to identify its origin . In this study a novel technique that characterizes physical attributes is proposed to provide insight into the processing route of unknown uranium ore concentrates and their calcination products . In particular this study focuses on the characteristics of the surface structure captured in scanning electron microscopy images at different magnification levels . Twelve common commercial processing routes of UOCs and their calcination products are investigated . Multiple input single output convolution neural networks are implemented to differentiate the processing routes . The proposed technique can determine the processing route of a given sample in under a second running on a graphics processing unit with an accuracy of more than 95 . The accuracy and speed of this proposed technique enable nuclear scientists to provide the preliminary identification results of interdicted material in a short time period . Furthermore this proposed technique uses a predetermined set of magnifications which in turn eliminates the human bias in selecting the magnification during the image acquisition process .
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Classifying the processing routes of uranium ore concentrates using multiple magnifications images. Achieving more than 95 accuracy in classification. Producing the results under a second when running on graphical processing unit.
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S0022311519312280
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Although the existence of a five metal phase as nanoparticles observed in irradiated nuclear fuel has been known for more than half a century the chemical and physical mechanisms controlling the formation and behavior of such particles remain stubbornly elusive . We present in this work new evidence for the presence of a separate nonmetallic phase associated with the metallic particles and containing a significant fraction of Te in addition to Pd . While this new phase potentially complicates the thermodynamic picture of a mixed alloy in equilibrium with the surrounding fuel environment it also provides new clues in the search for a chemical mechanism for Pd migration through the uranium dioxide matrix and the nucleation behavior of the particles . Fractionation between phases may subsequently affect the mechanical performance of fuels during irradiation and their interactions with the surrounding environment during long term waste storage .
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Nanoscale chemical segregation of Pd from the other noble metal phase NMP elements in UO. fuels has been observed. Detailed elemental analysis reveals the presence of a Te rich secondary phase within NMP particles. Ab initio chemical computations support the conclusion that the telluride phase drives fractionation of Pd and Ru. Results have implications for both the formation mechanism of NMP particles and their behavior in waste repositories.
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