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The precipitation of a second phase within the lattice of a material creates physical blockades through which a dislocation cannot pass. The result is that the dislocation must bend (which requires greater energy, or a greater stress to be applied) around the precipitates, which inevitably leaves residual dislocation loops encircling the second phase material and shortens the original dislocation. | 0 | Metallurgy |
Distribution of STAT4 is restricted to myeloid cells, thymus and testis. In resting human T cells it is expressed at very low levels, but its production is amplified by PHA stimulation. | 1 | Gene expression + Signal Transduction |
Pitting corrosion, or pitting, is extremely localized corrosion that leads to the creation of small holes in the material – nearly always a metal. The failures resulting from this form of corrosion can be catastrophic. With general corrosion it is easier to predict the amount of material that will be lost over time and this can be designed into the engineered structure. Pitting, like crevice corrosion can cause a catastrophic failure with very little loss of material. Pitting corrosion happens for passive materials. The classic reaction mechanism has been ascribed to Ulick Richardson Evans. | 0 | Metallurgy |
Labourers working in the smelting industry have reported respiratory illnesses inhibiting their ability to perform the physical tasks demanded by their jobs. | 0 | Metallurgy |
Plants for the production of pre-reduced iron ore are known as direct reduction plants. The principle involves exposing iron ore to the reducing action of a high-temperature gas (around 1000 °C). This gas is composed of carbon monoxide and dihydrogen, the proportions of which depend on the production process.
Generally speaking, there are two main types of processes:
* processes where the reducing gas is obtained from natural gas. In this case, the ore is reduced in tanks;
* processes where the reducing gas is obtained from coal. The reactor is generally an inclined rotary kiln, similar to those used in cement plants, in which coal is mixed with limestone and ore, then heated.
Another way of classifying processes is to distinguish between those where the reducing gases are produced in specific facilities separate from the reduction reactor - which characterizes most processes using natural gas - and those where the gases are produced inside the fusion reactor: coal-fired processes generally fall into this category. However, many "gas-fired" processes can be fed by gasification units producing a reducing gas from coal.
In addition, since the melting stage is necessary to obtain alloys, reduction-melting processes have been developed which, like blast furnaces, produce a more or less carburized liquid metal. Finally, many more or less experimental processes have been developed. | 0 | Metallurgy |
Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).
Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), and Valine (Val, V). | 1 | Gene expression + Signal Transduction |
Although the modern electric arc furnace is a highly efficient recycler of steel scrap, operation of an arc furnace shop can have adverse environmental effects. Much of the capital cost of a new installation will be devoted to systems intended to reduce these effects, which include:
* Enclosures to reduce high sound levels
* Dust collector for furnace off-gas
* Slag production
* Cooling water demand
* Heavy truck traffic for scrap, materials handling, and product
* Environmental effects of electricity generation
Since EAF steelmaking mainly use recycled materials like scrap iron and scrap steel, as their composition varies the resulting EAF slag and EAF dust can be toxic. EAF dust is collected by air pollution control equipment. It is called collected dust and usually contains heavy metals, such as zinc, lead and dioxins, etc. It is categorized as hazardous industrial waste and disposal is regulated.
Because of the very dynamic quality of the arc furnace load, power systems may require technical measures to maintain the quality of power for other customers; flicker and harmonic distortion are common power system side-effects of arc furnace operation. | 0 | Metallurgy |
These forms of AC have been reported in specific bacteria (Prevotella ruminicola and Rhizobium etli , respectively) and have not been extensively characterized. There are a few extra members (~400 in Pfam) known to be in class VI. Class VI enzymes possess a catalytic core similar to the one in Class III. | 1 | Gene expression + Signal Transduction |
As in the standard code, initiation is most efficient at AUG. In addition, GUG and UUG starts are documented in archaea and bacteria. In Escherichia coli, UUG is estimated to serve as initiator for about 3% of the bacteriums proteins. CUG is known to function as an initiator for one plasmid-encoded protein (RepA) in E. coli. In addition to the NUG initiations, in rare cases bacteria can initiate translation from an AUU codon as e.g. in the case of poly(A) polymerase PcnB and the InfC gene that codes for translation initiation factor IF3. The internal assignments are the same as in the standard code though UGA codes at low efficiency for tryptophan in Bacillus subtilis and, presumably, in Escherichia coli'.
The NCBI raw format is as follows, with UUG, CUG, AUU, AUC, AUA, AUG, and GUG marked as possible initiators:
AAs = FFLLSSSSYY**CC*WLLLLPPPPHHQQRRRRIIIMTTTTNNKKSSRRVVVVAAAADDEEGGGG
Starts = ---M------**--*----M------------MMMM---------------M------------
Base1 = TTTTTTTTTTTTTTTTCCCCCCCCCCCCCCCCAAAAAAAAAAAAAAAAGGGGGGGGGGGGGGGG
Base2 = TTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGG
Base3 = TCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAG
Initiation at AUC and AUA is not addressed in the NCBI description text, but both are indeed known to occur in E. coli. | 1 | Gene expression + Signal Transduction |
If a dopant is added to the material (example: Nd in BaTiO) the impurity will tend to stick to the grain boundaries. As the grain boundary tries to move (as atoms jump from the convex to concave surface) the change in concentration of the dopant at the grain boundary will impose a drag on the boundary. The original concentration of solute around the grain boundary will be asymmetrical in most cases. As the grain boundary tries to move, the concentration on the side opposite of motion will have a higher concentration and therefore have a higher chemical potential. This increased chemical potential will act as a backforce to the original chemical potential gradient that is the reason for grain boundary movement. This decrease in net chemical potential will decrease the grain boundary velocity and therefore grain growth. | 0 | Metallurgy |
Nickel titanium, also known as nitinol, is a metal alloy of nickel and titanium, where the two elements are present in roughly equal atomic percentages. Different alloys are named according to the weight percentage of nickel; e.g., nitinol 55 and nitinol 60.
Nitinol alloys exhibit two closely related and unique properties: the shape memory effect and superelasticity (also called pseudoelasticity). Shape memory is the ability of nitinol to undergo deformation at one temperature, stay in its deformed shape when the external force is removed, then recover its original, undeformed shape upon heating above its "transformation temperature." Superelasticity is the ability for the metal to undergo large deformations and immediately return to its undeformed shape upon removal of the external load. Nitinol can deform 10 to 30 times as much as ordinary metals and return to its original shape. Whether nitinol behaves with the shape memory effect or superelasticity depends on whether it is above its transformation temperature. Below the transformation temperature it exhibits the shape memory effect, and above that temperature it behaves superelastically. | 0 | Metallurgy |
Tarnish is a thin layer of corrosion that forms over copper, brass, aluminum, magnesium, neodymium and other similar metals as their outermost layer undergoes a chemical reaction. Tarnish does not always result from the sole effects of oxygen in the air. For example, silver needs hydrogen sulfide to tarnish, although it may tarnish with oxygen over time. It often appears as a dull, gray or black film or coating over metal. Tarnish is a surface phenomenon that is self-limiting, unlike rust. Only the top few layers of the metal react. The layer of tarnish seals and protects the underlying layers from reacting.
Tarnish actually preserves the underlying metal in outdoor use, and in this form is called patina. The formation of patina is necessary in applications such as copper roofing, and outdoor copper, bronze, and brass statues and fittings. Patina is the name given to tarnish on copper-based metals, while toning is a term for the type of tarnish which forms on coins. | 0 | Metallurgy |
The melting point of iron is experimentally well defined for pressures less than 50 GPa.
For greater pressures, published data (as of 2007) put the γ-ε-liquid triple point at pressures that differ by tens of gigapascals and 1000 K in the melting point. Generally speaking, molecular dynamics computer simulations of iron melting and shock wave experiments suggest higher melting points and a much steeper slope of the melting curve than static experiments carried out in diamond anvil cells.
The melting and boiling points of iron, along with its enthalpy of atomization, are lower than those of the earlier group 3d elements from scandium to chromium, showing the lessened contribution of the 3d electrons to metallic bonding as they are attracted more and more into the inert core by the nucleus; however, they are higher than the values for the previous element manganese because that element has a half-filled 3d subshell and consequently its d-electrons are not easily delocalized. This same trend appears for ruthenium but not osmium. | 0 | Metallurgy |
Corrosion Science is a peer-reviewed scientific journal published by Elsevier in 16 issues per year. Established in 1961, it covers a wide range of topics in the study of pure/applied corrosion and corrosion engineering, including but not limited to oxidation, biochemical corrosion, stress corrosion cracking, and corrosion control methods, as well as surface science and engineering. The editors-in-chief are J.M.C. Mol (Delft University of Technology) and O.R. Mattos (Federal University of Rio de Janeiro). | 0 | Metallurgy |
Several methods for detecting the RB1 gene mutations have been developed including a method that can detect large deletions that correlate with advanced stage retinoblastoma. | 1 | Gene expression + Signal Transduction |
The first two STAT proteins were identified in the interferon system. There are seven mammalian STAT family members that have been identified: STAT1, STAT2, STAT3, STAT4, STAT5 (STAT5A and STAT5B), and STAT6.
STAT1 homodimers are involved in type II interferon signalling, and bind to the GAS (Interferon-Gamma Activated Sequence) promoter to induce expression of interferon stimulated genes (ISG). In type I interferon signaling, STAT1-STAT2 heterodimer combines with IRF9 (Interferon Response Factor) to form ISGF3 (Interferon Stimulated Gene Factor), which binds to the ISRE (Interferon-Stimulated Response Element) promoter to induce ISG expression. | 1 | Gene expression + Signal Transduction |
The RNAP occasionally stops and starts moving backwards when it encounters a roadblock or some difficult sequences. When this happens, the EC gets stuck because the reactive 3 edge of the RNA is out of the active site. The transcript cleavage factor TFS (a TFIIS homolog) helps resolve this issue by generating a cut so that a new 3 end is available in the active site. Some archaeon have up to 4 paralogs of TFS with divergent functions. | 1 | Gene expression + Signal Transduction |
G protein can refer to two distinct families of proteins. Heterotrimeric G proteins, sometimes referred to as the "large" G proteins, are activated by G protein-coupled receptors and are made up of alpha (α), beta (β), and gamma (γ) subunits. "Small" G proteins (20-25kDa) belong to the Ras superfamily of small GTPases. These proteins are homologous to the alpha (α) subunit found in heterotrimers, but are in fact monomeric, consisting of only a single unit. However, like their larger relatives, they also bind GTP and GDP and are involved in signal transduction. | 1 | Gene expression + Signal Transduction |
Brass is an alloy composed of copper and zinc, usually for sheet metal, and casting in the proportion of seven parts of the former to three of the latter. Such a combination secures a good, brilliant colour. There are, however, varieties of tone ranging from a pale lemon colour to a deep golden brown, which depends upon a smaller or greater amount of zinc. In early times this metal seems to have been sparingly employed, but from the Middle Ages onward the industry in brass was a very important one, carried out on a vast scale and applied in widely different directions. The term "latten", which is frequently met with in old documents, is rather loosely employed, and is sometimes used for objects made of bronze; its true application is to the alloy we call brass. In Europe its use for artistic purposes centered largely in the region of the Meuse valley in south-east Belgium, together with north-eastern France, parts of the Netherlands and the Rhenish provinces of which Cologne was the center.
As far back as the 11th century the inhabitants of the town of Huy and Dinant are found working this metal; zinc they found in their own country, while for copper they went to Cologne or Dortmund, and later to the mines of the Harz Mountains. Much work was produced both by casting and repoussé, but it was in the former process that they excelled. Within a very short time the term "dinanderie" was coined to designate the work in brass which emanated from the foundries of Dinant and other towns in the neighbourhood. Their productions found their way to France, Spain, England and Germany. In London the Dinant merchants, encouraged by Edward III, established a "Hall" in 1329 which existed until the end of the 16th century; in France they traded at Rouen, Calais, Paris and elsewhere. The industry flourished for several centuries, but was weakened by quarrels with their rivals at the neighboring town of Bouvignes; in 1466 the town was sacked and destroyed by Charles the Bold. The brass-founders fled to Huy, Namur, Middleburg, Tournai and Bruges, where their work was continued.
The earliest piece of work in brass from the Meuse district is the baptismal font at St Bartholomew's Church, Liège (cf. Fig. 1 in Gallery), a large vessel resting on oxen, the outside of the bowl cast in high relief with groups of figures engaged in baptismal ceremonies; it was executed between 1113 and 1118 by Renier of Huy, the maker of a notable censer in the museum of Lille.
From this time onward a long series of exceptional works were executed for churches and cathedrals in the form of fonts, lecterns, paschal and altar candlesticks, tabernacles and chandeliers; fonts of simple outline have rich covers frequently adorned with figure subjects; lecterns are usually surmounted by an eagle of conventional form, but sometimes by a pelican (cf. Fig. 2); a griffin surmounts the lectern at Andenne. The stands which support these birds are sometimes of rich Gothic tracery work, with figures, and rest upon lions; later forms show a shaft of cylindrical form, with mouldings at intervals, and splayed out to a wide base. A number are found in Germany in the Cologne district, which may be of local manufacture; some remain in Venice churches. About a score have been noted in English churches, as at Norwich, St Albans, Croydon and elsewhere. For the most part they follow the same model, and were probably imported from Belgium. Fine brass chandeliers exist, at the Temple Church, Bristol (cf. Fig. 3), at St Michaels Mount, Cornwall, and in North Wales. The lecterns must have set the fashion in England for this type of object; for several centuries they are found, as at St Georges Chapel, Windsor Castle, Kings College Chapel, Cambridge, St Pauls Cathedral and some London churches (cf. Fig. 4). In the region of Cologne much brass-work was produced and still remains in the churches; mention must be made of the handsome screen in the Xanten Cathedral, the work, it is said, of a craftsman of Maastricht, the Netherlands, at the beginning of the 16th century. A modern example is the Hereford Screen in the Hereford Cathedral, made by George Gilbert Scott in 1862 in a variety of metals where brass dominates (cf. Fig. 5)
The Netherlands, Norway and Sweden also produced chandeliers, many of great size: the 16th- and 17th-century type is the well known "spider", large numbers of which were also made in England and still hang in many London and provincial churches. The Netherlands also showed a great liking for hammered work, and produced a large number of lecterns, altar candlesticks and the like in that method. The large dishes embossed with Adam and Eve and similar subjects are probably of Dutch origin, and found in neighbouring countries. These differ considerably from the brass dishes in which the central subject – the Annunciation, St George, St Christopher, the Agnus Dei, a mermaid or flowers – is surrounded by a band of letters, which frequently have no significance beyond that of ornamentation; the rims are stamped with a repeating pattern of small designs. This latter type of dish was probably the work of Nuremberg or Augsburg craftsmen, and it should be noticed that the whole of the ornament is produced by hammering into dies or by use of stamps; they are purely mechanical pieces.
Brass was widely used for smaller objects in churches and for domestic use. Flemish and German pictures show candlesticks, holy water stoups, reflectors, censers and vessels for washing the hands as used in churches. The inventories of Church goods in England made the time of the Reformation disclose a very large number of objects in latten which were probably made in the country. In general use was an attractive vessel known as the aquamanile (cf. Fig. 6); this is a water-vessel usually in the form of a standing lion, with a spout projecting from his mouth; on the top of the head is an opening for filling the vessel, and a lizard-shaped handle joins the back of the head with the tail. Others are in the form of a horse or ram; a few are in the form of a human bust, and some represent a mounted warrior. They were produced from the 12th to the 15th centuries. Countless are the domestic objects: mortars, small candlesticks, warming pans, trivets, fenders; these date mainly from the 17th and 18th centuries, when brass ornamentation was also frequently applied to clockdials, large and small. Two English developments during the 17th century call for special notice. The first was an attempt to use enamel with brass, a difficult matter, as brass is a bad medium for enamel.
A number of objects exist in the form of firedogs, candlesticks, caskets, plaques and vases, the body of which is of brass roughly cast with a design in relief; the hollow spaces between the lines of the design are filled in with patches of white, black, blue or red enamel, with very pleasing results (cf. Fig. 7). The nearest analogy is found in the small enamelled brass plaques and icons produced in Russia in the 17th and 18th centuries. The second use of brass is found in a group of locks of intricate mechanism, the cases of which are of brass cast in openwork with a delicate pattern of scroll work and bird forms sometimes engraved. A further development shows solid brass cases covered with richly engraved designs (cf. Fig. 8). The Victoria and Albert Museum of London, contains a fine group of these locks; others are in situ at Hampton Court Palace and in country mansions.
During the 18th century brass was largely used in the production of objects for domestic use; the manufacture of large hanging chandeliers also continued, together with wall-sconces and other lighting apparatus. In the latter half of the 19th century there came an increasing demand for ecclesiastical work in England; lecterns, alms dishes, processional crosses and altar furniture were made of brass; the designs were for the greater part adaptations of older work and without any great originality. | 0 | Metallurgy |
The process of converting pig iron into wrought iron (also known as bar iron) was at that time carried out in a finery forge, which was fuelled by charcoal. Charcoal was a limited resource, but coal, more widely available, could not be used because the sulphur in coal would adversely affect the quality of the wrought iron.
George Cranege worked in Coalbrookdale in Shropshire, at the ironworks established by Abraham Darby I, and his brother Thomas worked at a forge in Bridgnorth in Shropshire. They suggested to Richard Reynolds, manager of the works at Coalbrookdale, that the conversion process could be done in a reverbatory furnace, where the iron did not mix with the coal. Reynolds was sceptical, but authorized the brothers to try out the idea.
Richard Reynolds, in a letter dated 25 April 1766 to his colleague Thomas Goldney III, described his conversation with the Craneges and the experiment:
A patent for the process, dated 17 June 1766, in the name of the brothers Cranege, was secured. It apparently made little difference to the lives of the brothers. The process was improved soon afterwards, by Peter Onions who received a patent in 1783, and by Henry Cort who received patents in 1783 and 1784 for his improvements. | 0 | Metallurgy |
*MRPL9
*MRPL1
*MRPL10
*MRPL11
*MRPL12
*MRPL13
*MRPL14
*MRPL15
*MRPL16
*MRPL17
*MRPL18
*MRPL19
*MRPL2
*MRPL20
*MRPL21
*MRPL22
*MRPL23
*MRPL24
*MRPL27
*MRPL28
*MRPL3
*MRPL30
*MRPL32
*MRPL33
*MRPL35
*MRPL36
*MRPL37
*MRPL38
*MRPL4
*MRPL40
*MRPL41
*MRPL42
*MRPL43
*MRPL44
*MRPL45
*MRPL46
*MRPL47
*MRPL48
*MRPL49
*MRPL50
*MRPL51
*MRPL52
*MRPL53
*MRPL54
*MRPL55
*MRPL9
*MRPS10
*MRPS11
*MRPS12
*MRPS14
*MRPS15
*MRPS16
*MRPS17
*MRPS18A
*MRPS18B
*MRPS18C
*MRPS2
*MRPS21
*MRPS22
*MRPS23
*MRPS24
*MRPS25
*MRPS26
*MRPS27
*MRPS28
*MRPS30
*MRPS31
*MRPS33
*MRPS34
*MRPS35
*MRPS5
*MRPS6
*MRPS7
*MRPS9 | 1 | Gene expression + Signal Transduction |
Above the theoretical shear strength of the material, a type of defect-less flow can still occur, shearing the material. Dislocation motion through glide (any temperature) or dislocation creep (at high temperatures) is a typical mechanism found at high stresses in deformation maps. | 0 | Metallurgy |
Recent excavations in Middle Ganges Valley show iron working in India may have begun as early as 1800 BCE. In the 5th century BCE, the Greek historian Herodotus observed that "Indian and the Persian army used arrows tipped with iron." Ancient Romans used armour and cutlery made of Indian iron. Pliny the Elder also mentioned Indian iron. Muhammad al-Idrisi wrote the Hindus excelled in the manufacture of iron, and that it would be impossible to find anything to surpass the edge from Hindwani steel. Quintus Curtius wrote about an Indian present of steel to Alexander. Ferrum indicum appeared in the list of articles subject to duty under Marcus Aurelius and Commodus. Indian Wootz steel was held in high regard in Europe, and Indian iron was often considered to be the best. | 0 | Metallurgy |
In sub-Saharan West Africa, there were only two known source of copper that were commercially viable: Dkra near Nioro, Mali and Takedda in Azelik, Niger. Akjoujt was a significant source of copper, but due to the lack of timber it lost its significance in early historic times. The sources for West Africa's copper came from southern Morocco, northwestern Mauritania, the Byzantine Empire and Central Europe.
In West Africa, there is a great deal of documentation about copper in trade, but the travelers who wrote these documents only visited the major centers of West African polities and there is no information on the people who lived out the polities or from the savanna and forest zones to the south, in terms of their use of copper. Arab and European trader documented that the principal goods that were in demand in West African markets were salt and copper. There has been a lack of research done in the savannah and forest regions of West Africa so the evidence of the diffusion copper there is spotty at best. Despite West Africa's rich gold resources, high status people were most often buried with copper grave goods. The only sites prior to 1500 AD to have gold were Djenné, Tedaoust, and several tumuli in Senegal. | 0 | Metallurgy |
After initial sporadic work, archaeometallurgy was more widely institutionalised in the 1960s and 70s, with research groups in Britain (The British Museum, the UCL Institute of Archaeology, the Institute for Archeo-Metallurgical Studies (iams)), Germany (Deutsches Bergbau Museum) and the US (MIT and Harvard).
Specialisations within metallurgical focus on metallography of finished objects, mineralogy of waste products such as slag and manufacturing studies. | 0 | Metallurgy |
*Terne-plate is a similar product to tinplate, but the bath is not of tin, but of tin and lead mixed, the latter metal constituting from 7.59% of the whole. The name derives from "terne", meaning dull or tarnish. Terne-plates began to be produced in England about the middle of the 19th century, and became widely employed in the United States for roofing purposes. Other applications included fuel tanks and gas meters. The last Terne-plate mill in Brockmoor, West Midlands in the UK was closed in 2006.[https://www.expressandstar.com/news/business/2006/11/14/corus-axes-steel-plant/]
*For many purposes, tinplate has been replaced by galvanised (zinc-coated) vessels - though not for cooking, as zinc can be toxic. A Zinc protects iron electrolytically, that is, the zinc will oxidise and turn to a white powder to preserve the iron, whereas tin will only protect the iron if the tin-surface remains unbroken, as it electrolytically cannibalises unprotected iron to preserve itself. | 0 | Metallurgy |
In mammals, CPSF is a protein complex, consisting of six subunits: CPSF-160 (CPSF1), CPSF-100 (CPSF2), CPSF-73 (CPSF3), and CPSF-30 (CPSF4) kDa subunits, WDR33 and Fip1 (FIP1L1).
The subunits form two components: mammalian polyadenylation specificity factors (mPSF) and mammalian cleavage factor (mCF). The mPSF is made up of CPSF-160, WDR33, CPSF-30, and Fip1. It is necessary for PAS recognition and polyadenylation. The mCF is made up of CPSF-73, CPSF-100, and symplekin. It catalyzes the cleavage reaction by recognizing the histone mRNA 3' processing site.
CPSF-73 is a zinc-dependent hydrolase which cleaves the mRNA precursor between a CA dinucleotide just downstream the polyadenylation signal sequence AAUAAA.
CPSF-100 contributes to the endonuclease activity of CPSF-73.
CPSF-160 (160 kDa) is the largest subunit of CPSF and directly binds to the AAUAAA polyadenylation signal. 160 kDa has three β-propeller domains and a C-terminal domain.
CPSF-30 (30 kDa) has five Cys-Cys-Cys-His (CCCH) zinc-finger motifs near the N terminus and a CCCH zinc knuckle at the C terminus. Two isoforms of CPSF-30 exist and can be found in CPSF complexes. The RNA binding activity of CPSF-30 is mediated by its zinc-fingers 2 and 3. WD repeat domain 33 (146 kDa) has a WD40 domain near the N terminus. The WD40 domain interacts with RNA. WDR33 and CPSF-30 recognize the polyadenylation signal (PAS) in pre-mRNA, which aids in defining the position of RNA cleavage. CPSF-30 recognizes the AU-rich hexamer region by a cooperative, metal-dependent binding mechanism.
Although CPSF-160 is the largest subunit of CPSF, a study conducted by Schönemann et al., debate that WDR33 is responsible for recognizing the PAS and not CPSF-160 as previously believed. The study concluded that the reason that CPSF-160 was believed to be responsible for recognizing the PAS was due to the fact that the WDR33 subunit had not been discovered at the time of the claim.
Fip1 binds to U-rich RNAs by its arginine-rich C-terminus. It binds to RNA sequences upstream of the AAUAAA hexamer region in vitro. Fip1 and CPSF-160 recruit poly(A) polymerase (PAP) to the 3' processing site. PAP is stimulated by Poly(A) binding protein nuclear one to add the poly(A) tail, a non-templated adenosine residues, at the cleavage site.
Only CPSF-160, CPSF-30, Fip1, and WDR33 are necessary and sufficient to form an active CPSF subcomplex in AAUAAA-dependent polyadenylation. CPSF-73 and CPSF-100 are disposable.
CPSF recruits proteins to the 3' region. Identified proteins that are coordinated by CPSF activity include: cleavage stimulatory factor and the two poorly understood cleavage factors. The binding of the polynucleotide adenylyltransferase responsible for actually synthesizing the tail is a necessary prerequisite for cleavage, thus ensuring that cleavage and polyadenylation are tightly coupled processes. | 1 | Gene expression + Signal Transduction |
In metallurgy, the Scheil-Gulliver equation (or Scheil equation) describes solute redistribution during solidification of an alloy. | 0 | Metallurgy |
In molecular genetics, an untranslated region (or UTR) refers to either of two sections, one on each side of a coding sequence on a strand of mRNA. If it is found on the 5 side, it is called the 5 UTR (or leader sequence), or if it is found on the 3 side, it is called the 3 UTR (or trailer sequence). mRNA is RNA that carries information from DNA to the ribosome, the site of protein synthesis (translation) within a cell. The mRNA is initially transcribed from the corresponding DNA sequence and then translated into protein. However, several regions of the mRNA are usually not translated into protein, including the 5 and 3 UTRs.
Although they are called untranslated regions, and do not form the protein-coding region of the gene, uORFs located within the 5' UTR can be translated into peptides.
The 5 UTR is upstream from the coding sequence. Within the 5 UTR is a sequence that is recognized by the ribosome which allows the ribosome to bind and initiate translation. The mechanism of translation initiation differs in prokaryotes and eukaryotes. The 3 UTR is found immediately following the translation stop codon. The 3 UTR plays a critical role in translation termination as well as post-transcriptional modification.
These often long sequences were once thought to be useless or junk mRNA that has simply accumulated over evolutionary time. However, it is now known that the untranslated region of mRNA is involved in many regulatory aspects of gene expression in eukaryotic organisms. The importance of these non-coding regions is supported by evolutionary reasoning, as natural selection would have otherwise eliminated this unusable RNA.
It is important to distinguish the 5 and 3 UTRs from other non-protein-coding RNA. Within the coding sequence of pre-mRNA, there can be found sections of RNA that will not be included in the protein product. These sections of RNA are called introns. The RNA that results from RNA splicing is a sequence of exons. The reason why introns are not considered untranslated regions is that the introns are spliced out in the process of RNA splicing. The introns are not included in the mature mRNA molecule that will undergo translation and are thus considered non-protein-coding RNA. | 1 | Gene expression + Signal Transduction |
Demethylases are enzymes that remove methyl (CH) groups from nucleic acids, proteins (particularly histones), and other molecules. Demethylases are important epigenetic proteins, as they are responsible for transcriptional regulation of the genome by controlling the methylation of DNA and histones, and by extension, the chromatin state at specific gene loci. | 1 | Gene expression + Signal Transduction |
Chemokine receptors associate with G-proteins to transmit cell signals following ligand binding. Activation of G proteins, by chemokine receptors, causes the subsequent activation of an enzyme known as phospholipase C (PLC). PLC cleaves a molecule called phosphatidylinositol (4,5)-bisphosphate (PIP2) into two second messenger molecules known as Inositol triphosphate (IP3) and diacylglycerol (DAG) that trigger intracellular signaling events; DAG activates another enzyme called protein kinase C (PKC), and IP3 triggers the release of calcium from intracellular stores. These events promote many signaling cascades (such as the MAP kinase pathway) that generate responses like chemotaxis, degranulation, release of superoxide anions and changes in the avidity of cell adhesion molecules called integrins within the cell harbouring the chemokine receptor. | 1 | Gene expression + Signal Transduction |
miR-324-5p is a reverse strand miRNA, meaning it is produced from the 5' end of the associated RNA, and spans from position 7,223,342 to 7,223,364 on chromosome 17. Its sequence is CGCAUCCCCUAGGGCAUUGGUG.
miRNA forms following cleavage of pre-miRNA at the hairpin loop by the enzyme dicer within the cytosol. Interestingly, both strands of miR-324's pre-miRNA hairpin loop structure, miR-324-5p and miR-324-3p, become active miRNAs with distinct targets and functions. miR-324-5p has between 166 and 469 predicted targets, including regulators of cell growth, proliferation, survival, cytoskeletal structure, ATP transport, and ion channels. Though miR-324-5p is found on chromosome 17, its targets span across all chromosomes. | 1 | Gene expression + Signal Transduction |
The following reactions successively convert hematite (from iron ore) into magnetite, magnetite into ferrous oxide, and ferrous oxide into iron by reduction with carbon monoxide or hydrogen.
Carburizing produces cementite (FeC): | 0 | Metallurgy |
*Ensembl: [http://www.ensembl.org/biomart/martview/4e6c01c28faed033db52d0d30e4c21ab]
*OmicTools: [https://omictools.com/mtd-3-tool]
*Transcriptome Browser: [http://tagc.univ-mrs.fr/tbrowser/]
*ArrayExpress: [http://www.ebi.ac.uk/arrayexpress/] | 1 | Gene expression + Signal Transduction |
Quorum quenching is the process of preventing quorum sensing by disrupting signalling. This is achieved by inactivating signalling enzymes, by introducing molecules that mimic signalling molecules and block their receptors, by degrading signalling molecules themselves, or by a modification of the quorum sensing signals due to an enzyme activity. | 1 | Gene expression + Signal Transduction |
The unlinked galR gene encodes the repressor for this system. A tetrameric GalR repressor binds to 2 operators, one located at +55 and one located at -60 relative to the PG1 start site. Looping of the DNA blocks the access of RNA polymerase to promoters and/or inhibits formation of the open complex. This looping requires the presence of the histone-like protein, HU to facilitate the formation of the structure and allow for proper repression. When GalR binds as a dimer to the -60 site only, the promoter PG2 is activated, not repressed, allowing basal levels of GalE to be produced. In this state, the PG1 promoter is inactivated through interactions with the alpha subunit of RNA polymerase. Activity of this repressor protein is controlled based on the levels of D-galactose in the cell. Increased levels of this sugar inhibit the activity of the repressor by binding allosterically, resulting in a conformational change of the protein, which suppresses its interactions with RNA polymerase and DNA. This induces the activity of the operon, which will increase the rate of galactose metabolism.
The gal operon is also controlled by CRP-cAMP, similarly to the lac operon. CRP-cAMP binds to the -35 region, promoting transcription from PG1 but inhibiting transcription from PG2. This is accomplished due to the location of the activation sequence. When CRP-cAMP binds the activating sequence, it blocks RNA polymerase from establishing an open complex with PG2, but enhances a closed complex with RNA polymerase at PG1. This represses the activity of the PG2 promoter, and increases the activity of the PG1 promoter. When cells are grown in glucose, basal level transcription occurs from PG2. | 1 | Gene expression + Signal Transduction |
E. coli has seven main sigma factors, five of which have a specific anti-sigma factor. The anti-sigma factor binding to its sigma factors depends upon environmental cues. This mechanism blocks the transcription of genes that are unnecessary in new conditions. The table below shows five sigma factors, what process it affects, and its corresponding anti-sigma factor. In E. coli, sigma factors transcribe their anti-sigma factors; this creates a negative feedback loop. The sigma factor can be regulated when the anti-sigma factor is transcribed and the anti-sigma factor when the sigmas gene is transcribed. Sigma factors 70 and 54 don't have specific anti-sigma factors; they have other negative feedback loop mechanisms. | 1 | Gene expression + Signal Transduction |
To identify diverse post-transcriptional modifications of RNA molecules and determine the transcriptome-wide landscape of RNA modifications by means of next generation RNA sequencing, recently many studies have developed conventional or specialised sequencing methods. Examples of specialised methods are MeRIP-seq, m6A-seq, PA-mC-seq , methylation-iCLIP, m6A-CLIP, Pseudo-seq, Ψ-seq, CeU-seq, Aza-IP and RiboMeth-seq). Many of these methods are based on specific capture of the RNA species containing the specific modification, for example through antibody binding coupled with sequencing of the captured reads. After the sequencing these reads are mapped against the whole transcriptome to see where they originate from. Generally with this kind of approach it is possible to see the location of the modifications together with possible identification of some consensus sequences that might help identification and mapping further on. One example of the specialize methods is PA-mC-seq. This method was further developed from PA-mA-seq method to identify mC modifications on mRNA instead of the original target N6-methyladenosine. The easy switch between different modifications as target is made possible with a simple change of the capturing antibody form m6A specific to mC specific. Application of these methods have identified various modifications (e.g. pseudouridine, mA, m5C, 2′-O-Me) within coding genes and non-coding genes (e.g. tRNA, lncRNAs, microRNAs) at single nucleotide or very high resolution. | 1 | Gene expression + Signal Transduction |
A "refractory" gold ore is an ore that has ultra-fine gold particles disseminated throughout its gold occluded minerals. These ores are naturally resistant to recovery by standard cyanidation and carbon adsorption processes. These refractory ores require pre-treatment in order for cyanidation to be effective in recovery of the gold. A refractory ore generally contains sulphide minerals, organic carbon, or both. Sulphide minerals are impermeable minerals that occlude gold particles, making it difficult for the leach solution to form a complex with the gold. Organic carbon present in gold ore may adsorb dissolved gold-cyanide complexes in much the same way as activated carbon. This so-called "preg-robbing" carbon is washed away because it is significantly finer than the carbon recovery screens typically used to recover activated carbon.
Pre-treatment options for refractory ores include:
# Roasting
# Bio-oxidation, such as bacterial oxidation
# Pressure oxidation
# Albion process
The refractory ore treatment processes may be preceded by concentration (usually sulphide flotation). Roasting is used to oxidize both the sulphur and organic carbon at high temperatures using air and/or oxygen. Bio-oxidation involves the use of bacteria that promote oxidation reactions in an aqueous environment. Pressure oxidation is an aqueous process for sulphur removal carried out in a continuous autoclave, operating at high pressures and somewhat elevated temperatures. The Albion process utilises a combination of ultrafine grinding and atmospheric, auto-thermal, oxidative leaching. | 0 | Metallurgy |
The Kesternich test is a common name for the corrosion test with sulfur dioxide (SO) under general moisture condensation. This test was developed in 1951 by Wilhelm Kesternich to simulate the damaging effects of acid rain.
Acid rain and acidic industrial pollutants are corrosive and can degrade coatings and plated surfaces. Kesternich testing, or sulfur dioxide testing, simulates acid rain or industrial chemical exposure to evaluate the relative corrosion resistance of the coating, substrate, or part itself. The test can be used for coatings or for base materials.
The test method is defined by various standards, DIN EN ISO 6988, DIN 50018, ASTM G87, ISO 3231, ISO 22479 are the most common. The parts to be tested are placed in a test chamber with a capacity of 300L and exposed to warm, moist air in combination with a certain amount of sulfur dioxide
Note: Sulfur is interchangeable with Sulphur and SO2 is the abbreviation for Sulfur/Sulphur Dioxide | 0 | Metallurgy |
The site was opened in 1931 by the Lindsay Light and Chemical Company. It processed ores like monazite to produce elements, including thorium and uranium. It also made gaslight mantles, and during World War II, hydrofluoric acid.
In 1958, it became owned by American Potash and Chemical Company (AMPOT), which at one point had a Lindsay Chemical Division.
In 1967, AMPOT, and thus the facility, were bought by Kerr-McGee. The Rare Earths Facility were closed by Kerr-McGee in 1973.
In 2005, KMCC was spun off from Kerr-McGee as Tronox, shortly before Kerr-McGee was acquired by Anadarko Petroleum. Tronox inherited responsibility for the Rare Earths Facility and other sites. Tronox went bankrupt in 2009 and shareholders sued Anadarko Petroleum, partly for having misled investors in Tronox about its environmental debts. | 0 | Metallurgy |
Dynamic recrystallization (DRX) is a type of recrystallization process, found within the fields of metallurgy and geology. In dynamic recrystallization, as opposed to static recrystallization, the nucleation and growth of new grains occurs during deformation rather than afterwards as part of a separate heat treatment. The reduction of grain size increases the risk of grain boundary sliding at elevated temperatures, while also decreasing dislocation mobility within the material. The new grains are less strained, causing a decrease in the hardening of a material. Dynamic recrystallization allows for new grain sizes and orientation, which can prevent crack propagation. Rather than strain causing the material to fracture, strain can initiate the growth of a new grain, consuming atoms from neighboring pre-existing grains. After dynamic recrystallization, the ductility of the material increases.
In a stress–strain curve, the onset of dynamic recrystallization can be recognized by a distinct peak in the flow stress in hot working data, due to the softening effect of recrystallization. However, not all materials display well-defined peaks when tested under hot working conditions. The onset of DRX can also be detected from inflection point in plots of the strain hardening rate against stress. It has been shown that this technique can be used to establish the occurrence of DRX when this cannot be determined unambiguously from the shape of the flow curve.
If stress oscillations appear before reaching the steady state, then several recrystallization and grain growth cycles occur and the stress behavior is said to be of the cyclic or multiple peak type. The particular stress behavior before reaching the steady state depends on the initial grain size, temperature, and strain rate.
DRX can occur in various forms, including:
* Geometric dynamic recrystallization
* Discontinuous dynamic recrystallization
* Continuous dynamic recrystallization
Dynamic recrystallization is dependent on the rate of dislocation creation and movement. It is also dependent on the recovery rate (the rate at which dislocations annihilate). The interplay between work hardening and dynamic recovery determines grain structure. It also determines the susceptibility of grains to various types of dynamic recrystallization. Regardless of the mechanism, for dynamic crystallization to occur, the material must have experienced a critical deformation. The final grain size increases with increased stress. To achieve very fine-grained structures the stresses have to be high.
Some authors have used the term postdynamic or metadynamic to describe recrystallization that occurs during the cooling phase of a hot-working process or between successive passes. This emphasises the fact that the recrystallization is directly linked to the process in question, while acknowledging that there is no concurrent deformation. | 0 | Metallurgy |
While lists of noble metals can differ, they tend to cluster around the six platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, platinum) plus gold.
In addition to this terms function as a compound noun, there are circumstances where noble is used as an adjective for the noun metal'. A galvanic series is a hierarchy of metals (or other electrically conductive materials, including composites and semimetals) that runs from noble to active, and allows one to predict how materials will interact in the environment used to generate the series. In this sense of the word, graphite is more noble than silver and the relative nobility of many materials is highly dependent upon context, as for aluminium and stainless steel in conditions of varying pH.
The term noble metal can be traced back to at least the late 14th century and has slightly different meanings in different fields of study and application.
Prior to Mendeleev's publication in 1869 of the first (eventually) widely accepted periodic table, Odling published a table in 1864, in which the "noble metals" rhodium, ruthenium, palladium; and platinum, iridium, and osmium were grouped together, and adjacent to silver and gold. | 0 | Metallurgy |
The GLD-2 protein together with 136 proteins more, is involved in the molecular process of hematopoietic progenitor cell differentiation, in the human proteome. This is the process in which precursor cell type acquires the specialized features of a hematopoietic progenitor cell, a kind of cell types including myeloid progenitor cells and lymphoid progenitor cells. | 1 | Gene expression + Signal Transduction |
Oligonucleotides are chemically synthesized using building blocks called nucleoside phosphoramidites. These can be normal or modified nucleosides which have protecting groups to prevent their amines, hydroxyl groups and phosphate groups from interacting incorrectly. One phosphoramidite is added at a time, the 5 hydroxyl group is deprotected and a new base is added and so on. The chain grows in the 3 to 5' direction, which is backwards relative to biosynthesis. At the end, all the protecting groups are removed. Nevertheless, being a chemical process, several incorrect interactions occur leading to some defective products. The longer the oligonucleotide sequence that is being synthesized, the more defects there are, thus this process is only practical for producing short sequences of nucleotides. The current practical limit is about 200 bp (base pairs) for an oligonucleotide with sufficient quality to be used directly for a biological application. HPLC can be used to isolate products with the proper sequence. Meanwhile, a large number of oligos can be synthesized in parallel on gene chips. For optimal performance in subsequent gene synthesis procedures they should be prepared individually and in larger scales. | 1 | Gene expression + Signal Transduction |
A third group of genes in which mutations lead to a significant susceptibility to cancer is the class of landscaper genes. Products encoded by landscaper genes do not directly affect cellular growth, but when mutated, contribute to the neoplastic growth of cells by fostering stromal environments conducive to unregulated cell proliferation.
Landscaper genes encode gene products that control the microenvironment in which cells grow. Growth of cells depends both on cell-to-cell interactions and cell-to-extracellular matrix (ECM) interactions. Mechanisms of control via regulation of extracellular matrix proteins, cellular surface markers, cellular adhesion molecules, and growth factors have been proposed.
Cells communicate with each other via the ECM through both direct contact and through signaling molecules. Stromal cell abnormalities arising from gene products coded by faulty landscaper genes could induce abnormal cell growth on the epithelium, leading to cancer of that tissue.
Biochemical cascades consisting of signaling proteins occur in the ECM and play an important role to the regulation of many aspects of cell life. Landscaper genes encode products that determine the composition of the membranes in which cells live. For example, large molecular weight glycoproteins and proteoglycans have been found to in association with signaling and structural roles. There exist proteolytic molecules in the ECM that are essential for clearing unwanted molecules, such as growth factors, cell adhesion molecules, and others from the space surrounding cells. It is proposed that landscaper genes control the mechanisms by which these factors are properly cleared. Different characteristics of these membranes lead to different cellular effects, such as differing rates of cell proliferation or differentiation. If, for example, the ECM is disrupted, incoming cells, such as those of the immune system, can overload the area and release chemical signals that induce abnormal cell proliferation. These conditions lead to an environment conducive to tumor growth and the cancerous phenotype. | 1 | Gene expression + Signal Transduction |
The increase in use of Terfenol-D in transducers required new production techniques that increased production rates and quality because the original methods were unreliable and small scale. There are four methods that are used to produce Terfenol-D, which are free stand zone melting, modified Bridgman, sintered powder compact, and polymer matrix composites.
The first two methods, free stand zone melting (FSZM) and modified Bridgman (MB), are capable of producing Terfenol-D that has high magnetostrictive properties and energy densities. However, FSZM cannot produce a rod larger than 8 mm in diameter due to the surface tension of the Terfenol-D and how the FSZM process has no container to restrict the material. The MB process offers a minimum of 10 mm diameter size and is only restricted due to the wall interfering with the crystal growth. Both methods create solid crystals that require later manufacturing if a geometry other than a right-angle cylinder is needed. The solid crystals produced have a fine lamellar structure.
The other two techniques, sintered powder compact and polymer matrix composites, are powder based. These techniques allow for intricate geometry and detail. However, the size is limited to 10mm in diameter and 100mm in length due to the molds used. The resulting microstructures of these powder based methods differ from the solid crystal ones because they do not have a lamellar structure and have a lower density. However, all methods have similar magnetostrictive properties.
Due to size restriction, MB is the best process to produce Terfenol-D, however it is a labor-intensive method. A newer process like MB is ET-Ryma crystal growth (ECG) that results in larger diameter Terfenol-D crystals and increased magnetostrictive performance. The reliability of magnetostrictive properties of the Terfenol-D throughout the life of the material is increased by using ET-Ryma.
Terfenol-D has some minor drawbacks which stem from its material properties. Terfenol-D has low ductility and low fracture resistance. To solve this, Terfenol-D has been added to polymers and other metals to create composites. When added to polymers, the stiffness of the resulting composite is low. When composites of Terfenol-D with ductile metal binders are created, the resulting material has increased stiffness and ductility with reduced magnetostrictive properties. These metal composites may be formed by explosion compaction. In a study done on processing Terfenol-D alloys, the resulting alloys created using copper and Terfenol-D had increased strength and hardness values, which supports the theory that the composites of ductile metal binders and Terfenol-D result in a stronger and more ductile material. | 0 | Metallurgy |
According to metallurgist Jack Harris, "Oxidation is usually accompanied by a net expansion so that when it occurs in a confined space stresses are generated in the metal component itself or in any surrounding medium such as stone or cement. So much energy is released by oxidation that the stresses generated are of sufficient magnitude to deform or fracture all known materials."
As early as 1915, it was recognized that certain modern metal alloys are more susceptible to excessive oxidation when subjected to weathering than other metals. At that time, there was a trend to replace wrought iron fasteners with mild steel equivalents, which were less expensive. Unexpectedly, the mild steel fasteners failed in real world use much more quickly than anticipated, leading to a return to use of wrought iron in certain applications where length of service was important. | 0 | Metallurgy |
Survivin is known to be expressed during fetal development and across most tumour cell types, but is rarely present in normal, non-malignant adult cells. Tamm et al. showed that survivin was expressed in all 60 different human tumour lines used in the National Cancer Institute's cancer drug-screening program, with the highest levels of expression in breast and lung cancer lines and the lowest levels in renal cancers. Knowing the relative expression levels of survivin in different tumour types may prove helpful as survivin-related therapy may be administered depending on the expression level and reliance of the tumour type on survivin for resistance to apoptosis. | 1 | Gene expression + Signal Transduction |
The individual hearths are lined with refractory brick, and the rabble arms are typically a force-cooled metal alloy. The entire structure is enclosed in a cylindrical brick-lined steel shell. | 0 | Metallurgy |
In certain cases, the plane stress model can be used in the analysis of gently curved surfaces. For example,
consider a thin-walled cylinder subjected to an axial compressive load uniformly distributed along its rim, and filled with a pressurized fluid. The internal pressure will generate a reactive hoop stress on the wall, a normal tensile stress directed perpendicular to the cylinder axis and tangential to its surface. The cylinder can be conceptually unrolled and analyzed as a flat thin rectangular plate subjected to tensile load in one direction and compressive load in another other direction, both parallel to the plate. | 0 | Metallurgy |
Thomas Whitwell (24 October 1837 – 5 August 1878) was a British engineer, inventor and metallurgist.
Known as Tom, he was the third son of William and Sarah Whitwell of Kendal. Tom was initially educated at home via private tutors he was sent to the Quaker run York School at 10 years old. In 1858, at 16, he travelled with his elder brother William to Darlington. As apprentice to Alfred Kitching in his locomotive building shop he learned engineering and metallurgy. From there he continued to build his skills, working with Robert Stephenson & Co in Newcastle.
In 1859 he and William started iron-smelting at Thornaby. Iron ore had been discovered in the area four years previously. The brothers designed and built large scale hot blast fire brick stoves that were much larger and more efficient that anything built in the area until that point. By 1873 the three re-built blast furnaces were 80 feet high and 22 feet in diameter and the works had over 750 employees.
In 1878 Tom died due to an accident at his works. A steam explosion caught him and his foreman John Thompson whilst they were investigating a problem with the rolling mill furnace.
The works continued to run under family ownership, under the chairmanship of Tom's nephew William Fry Whitwell until 1922 when they were eventually closed due to a global glut of pig iron. | 0 | Metallurgy |
The working gristmill grinds wheat and corn into flour, which is available for sale during the twice-yearly shows. During the summer months, the museum grows sorghum cane, which is made into molasses for the fall show. | 0 | Metallurgy |
Attenuators may be classified according to the type of molecule which induces the change in RNA structure. It is likely that transcription-attenuation mechanisms developed early, perhaps prior to the archaea/bacteria separation and have since evolved to use a number of different sensing molecules (the tryptophan biosynthetic operon has been found to use three different mechanisms in different organisms.) | 1 | Gene expression + Signal Transduction |
The complex changes that the Schwann cell undergoes during the process of myelination of peripheral nerve fibers have been observed and studied by many. The initial envelopment of the axon occurs without interruption along the entire extent of the Schwann cell. This process is sequenced by the in-folding of the Schwann cell surface so that a double membrane of the opposing faces of the in-folded Schwann cell surface is formed. This membrane stretches and spirally wraps itself over and over as the in-folding of the Schwann cell surface continues. As a result, the increase in the thickness of the extension of the myelin sheath in its cross-sectional diameter is easily ascertained. It is also evident that each of the consecutive turns of the spiral increases in size along the length of the axon as the number of turns increase. However, it is not clear whether or not the increase in length of the myelin sheath can be accounted solely by the increase in length of axon covered by each successive turn of the spiral, as previously explained.
At the junction of two Schwann cells along an axon, the directions of the lamellar overhang of the myelin endings are of opposite sense. This junction, adjacent of the Schwann cells, constitutes the region designated as the node of Ranvier. | 1 | Gene expression + Signal Transduction |
In most cases, splicing removes introns as single units from precursor mRNA transcripts. However, in some cases, especially in mRNAs with very long introns, splicing happens in steps, with part of an intron removed and then the remaining intron is spliced out in a following step. This has been found first in the Ultrabithorax (Ubx) gene of the fruit fly, Drosophila melanogaster, and a few other Drosophila genes, but cases in humans have been reported as well. | 1 | Gene expression + Signal Transduction |
Mercury has been smelted from cinnabar for thousands of years. Mercury dissolves many metals, such as gold, silver, and tin, to form amalgams (an alloy in a soft paste or liquid form at ambient temperature). Amalgams have been used since 200 BC in China for gilding objects such as armor and mirrors with precious metals. The ancient Romans often used mercury-tin amalgams for gilding their armor. The amalgam was applied as a paste and then heated until the mercury vaporized, leaving the gold, silver, or tin behind. Mercury was often used in mining, to extract precious metals like gold and silver from their ores. | 0 | Metallurgy |
In 1831, the East India Company officer William Elliott made a facsimile of the inscription. Based on this facsimile, in 1834, James Prinsep published a lithograph in the Journal of the Royal Asiatic Society of Great Britain and Ireland. However, this lithograph did not represent every single word of the inscription correctly. Some years later, British engineer T. S. Burt made an ink impression of the inscription. Based on this, in 1838, Prinsep published an improved lithograph in the same journal, with his reading of the script and translation of the text.
Decades later, Bhagwan Lal Indraji made another copy of the inscription on a cloth. Based on this copy, Bhau Daji Lad published a revised text and translation in 1875, in Journal of the Bombay Branch of the Royal Asiatic Society. This reading was the first one to correctly mention the kings name as Chandra. In 1888, John Faithfull Fleet published a critical edition of the text in Corpus Inscriptionum Indicarum'.
In 1945, Govardhan Rai Sharma dated the inscription to the first half of the 5th century CE, on paleographic grounds. He observed that its script was similar to the writing on other Gupta-Era inscriptions, including the ones discovered at Bilsad (415 CE), Baigram (449 CE), and Kahanum (449 CE). R. Balasubramaniam (2005) noted that the characters of the Delhi inscription closely resembled the dated inscriptions of Chandragupta II, found at Udayagiri in Madhya Pradesh. | 0 | Metallurgy |
Pioneer factors can function passively, by acting as a bookmark for the cell to recruit other transcription factors to specific genes in condensed chromatin. This can be important for priming the cell for a rapid response as the enhancer is already bound by a pioneer transcription factor giving it a head start towards assembling the transcription preinitiation complex. Hormone responses are often quickly induced in the cell using this priming method such as with the estrogen receptor. Another form of priming is when an enhancer is simultaneously bound by activating and repressing pioneer factors. This balance can be tipped by dissociation of one of the factors. In hepatic cell differentiation the activating pioneer factor FOXA1 recruits a repressor, grg3, that prevents transcription until the repressor is down-regulated later on in the differentiation process.
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In a direct role pioneer factors can bind an enhancer and recruit activation complex that will modify the chromatin directly. The change in the chromatin changes the affinity, decreasing the affinity of the pioneer factor such that it is replaced by a transcription factor that has a higher affinity. This is a mechanism for the cell to switch a gene on was observed with glucocorticoid receptor recruiting modification factors that then modify the site to bind activated estrogen receptor which was coined as a “bait and switch” mechanism. | 1 | Gene expression + Signal Transduction |
As of December 20, 2006, ORegAnno contained 4220 regulatory sequences (excluding deprecated records) for 2190 transcription factor binding sites, 1853 regulatory regions (enhancers, promoters, etc.), 170 regulatory polymorphisms, and 7 regulatory haplotypes for 17 different organisms (predominantly Drosophila melanogaster, Homo sapiens, Mus musculus, Caenorhabditis elegans, and Rattus norvegicus in that order). These records were obtained by manual curation of 828 publications by 45 ORegAnno users from the gene regulation community. The ORegAnno publication queue contained 4215 publications of which 858 were closed, 34 were in progress (open status), and 3321 were awaiting annotation (pending status). ORegAnno is continually updated and therefore current database contents should be obtained from [http://www.oreganno.org www.oreganno.org]. | 1 | Gene expression + Signal Transduction |
The signal that starts the MAPK/ERK pathway is the binding of extracellular mitogen to a cell surface receptor. This allows a Ras protein (a Small GTPase) to swap a GDP molecule for a GTP molecule, flipping the "on/off switch" of the pathway. The Ras protein can then activate MAP3K (e.g., Raf), which activates MAP2K, which activates MAPK. Finally, MAPK can activate a transcription factor, such as Myc. This process is described in more detail below. | 1 | Gene expression + Signal Transduction |
At atmospheric pressure, three allotropic forms of iron exist, depending on temperature: alpha iron (α-Fe, ferrite), gamma iron (γ-Fe, austenite), and delta iron (δ-Fe). At very high pressure, a fourth form exists, epsilon iron (ε-Fe, hexaferrum). Some controversial experimental evidence suggests the existence of a fifth high-pressure form that is stable at very high pressures and temperatures.
The phases of iron at atmospheric pressure are important because of the differences in solubility of carbon, forming different types of steel. The high-pressure phases of iron are important as models for the solid parts of planetary cores. The inner core of the Earth is generally assumed to consist essentially of a crystalline iron-nickel alloy with ε structure. The outer core surrounding the solid inner core is believed to be composed of liquid iron mixed with nickel and trace amounts of lighter elements. | 0 | Metallurgy |
Sintering and hot isostatic pressing are processing techniques used to densify materials from a loosely packed "green body" into a solid object with physically merged grains. Sintering occurs below the melting point, and causes adjacent particles to merge at their boundaries, creating a strong bond between them. In hot isostatic pressing, a sintered material is placed in a pressure vessel and compressed from all directions (isostatically) in an inert atmosphere to affect densification. | 0 | Metallurgy |
Many alloys of industrial significance have some volume fraction of second phase particles, either as a result of impurities or from deliberate alloying additions. Depending on their size and distribution such particles may act to either encourage or retard recrystallization. | 0 | Metallurgy |
The characteristics capable of supporting Type 1 pits were determined empirically by Lucey after examining the compositions of waters in which the pitting behaviour was known. They should be cold, less than 30°C, hard or moderately hard, 170 to 300 mg/L carbonate hardness, and organically pure. Organically pure waters usually originate from deep wells, or boreholes. Surface waters from rivers or lakes contain naturally occurring organic compounds that inhibit the formation of Type 1 pits, unless a deflocculation treatment has been carried out that removes organic material. Type 1 pitting is relatively uncommon in North America and this may be a result of the lower population density allowing a significant proportion of the potable water to be obtained from surface derived sources. In addition to being cold hard and organically pure, the water needs a specific chemistry. The effect of the water chemistry can be empirically determined though use of the Pitting Propensity Rating (PPR) a number that takes into account the sulfate, chloride, nitrate and sodium ion concentrations of the water as well as its acidity or pH. A water with a positive PPR has been shown to be capable of propagating Type 1 pits. | 0 | Metallurgy |
# Excitatory synapse: Enhances the probability of depolarization in postsynaptic neurons and the initiation of an action potential.
# Inhibitory Synapse: Diminishes the probability of depolarization in postsynaptic neurons and the initiation of an action potential.
An influx of Na+ driven by excitatory neurotransmitters opens cation channels, depolarizing the postsynaptic membrane toward the action potential threshold. In contrast, inhibitory neurotransmitters cause the postsynaptic membrane to become less depolarized by opening either Cl- or K+ channels, reducing firing. Depending on their release location, the receptors they bind to, and the ionic circumstances they encounter, various transmitters can be either excitatory or inhibitory. For instance, acetylcholine can either excite or inhibit depending on the type of receptors it binds to. For example, glutamate serves as an excitatory neurotransmitter, in contrast to GABA, which acts as an inhibitory neurotransmitter. Additionally, dopaminergic is a neurotransmitter that exerts dual effects, displaying both excitatory and inhibitory impacts through binding to distinct receptors.
The membrane potential prevents Cl- from entering the cell, even when its concentration is much higher outside than inside. The resting potential for Cl- in many neurons is quite negative, nearly equal to the resting potential. Opening Cl- channels tends to buffer the membrane potential, but this effect is countered when the membrane starts to depolarize, allowing more negatively charged Cl- ions to enter the cell. Consequently, it becomes more difficult to depolarize the membrane and excite the cell when Cl- channels are open. Similar effects result from the opening of K+ channels. The significance of inhibitory neurotransmitters is evident from the effects of toxins that impede their activity. For instance, strychnine binds to glycine receptors, blocking the action of glycine and leading to muscle spasms, convulsions, and death. | 1 | Gene expression + Signal Transduction |
Pertussis toxin (PT) is a protein-based AB-type exotoxin produced by the bacterium Bordetella pertussis, which causes whooping cough. PT is involved in the colonization of the respiratory tract and the establishment of infection. Research suggests PT may have a therapeutic role in treating a number of common human ailments, including hypertension, viral infection, and autoimmunity. | 1 | Gene expression + Signal Transduction |
The erythropoietin receptor (EpoR) is a protein that in humans is encoded by the EPOR gene. EpoR is a 52kDa peptide with a single carbohydrate chain resulting in an approximately 56-57 kDa protein found on the surface of EPO responding cells. It is a member of the cytokine receptor family. EpoR pre-exists as dimers. These dimers were originally thought to be formed by extracellular domain interactions, however, it is now assumed that it is formed by interactions of the transmembrane domain and that the original structure of the extracellular interaction site was due to crystallisation conditions and does not depict the native conformation. Binding of a 30 kDa ligand erythropoietin (Epo), changes the receptor's conformational change, resulting in the autophosphorylation of Jak2 kinases that are pre-associated with the receptor (i.e., EpoR does not possess intrinsic kinase activity and depends on Jak2 activity). At present, the best-established function of EpoR is to promote proliferation and rescue of erythroid (red blood cell) progenitors from apoptosis. | 1 | Gene expression + Signal Transduction |
During quiescence, the DREAM complex represses G1/S and G2/M gene expression. In mammalian systems, chromatin-immunoprecipitation (ChIP) studies have revealed that DREAM components are found together at promoters of genes that peak in G1/S or G2/M phase. Abrogation of the DREAM complex on the other hand, led to increased expression of E2F regulated genes normally repressed in the G0 phase. Contrary to mammalian cells, the fly dREAM complex was found at almost one-third of all promoters, which may reflect a broader role for dREAM in gene regulation, such as programmed cell death of neural precursor cells.
Docking of the DREAM complex to promoters is achieved by binding of LIN-54 to regions known as cell cycle genes homology region (CHR). These are specific sequence of nucleotides that are commonly found in the promoters of genes expressed during late S phase or G2/M phase. Docking can also be achieved via E2F proteins binding to sequences known as cell cycle-dependent element sites (CDEs). Some cell cycle dependent genes have been found where both CHRs and CDEs are in proximity to one another. Because p130-E2F4 can form stable associations with the MuvB complex, the proximity of CHRs to CDEs suggests that affinity of binding of the DREAM complex to target genes is cooperatively improved by association with both the binding sites.
When DREAM is docked onto the promoter, p130 is bound to LIN52, and this association inhibits LIN52 binding to chromatin modifier proteins. Therefore, unlike RB-E2F, the DREAM complex is unlikely to directly recruit chromatin modifiers to repress gene expression, although some associations have been suggested. DREAM complex may instead down-regulate gene expression by affecting nucleosome positioning. Compacted DNA at transcription start sites inhibit gene expression by blocking the docking of RNA polymerase. In worms for example, loss of a MuvB complex protein, LIN35, leads to loss of repressive histone associations and high expression of cell cycle dependent genes. However, direct evidence for the link between repressive histones and the DREAM complex remains to be elucidated. | 1 | Gene expression + Signal Transduction |
The Museum of the History of Donetsk Metallurgical Plant was created in 1955, and it is located in the Technology House. The idea for its creation came from the director of the DMZ, Pavel Vasilyevich Andreev. The museum consists of more than 3000 exhibits. In 1971 the museum was awarded the title of national museum. Among the exhibits are certificates for products manufactured by the plant in 1900, original photographs of the Nizhny Novgorod industrial exhibition in 1896 and others.
On February 16, 2012, a branch of the Museum of the History of the Donetsk Metallurgical Plant was opened in the lower floor of the St. Ignatius Church, which is dedicated to Ignatius of Mariupol. | 0 | Metallurgy |
Pelletizing of animal feeds can result in pellets from (shrimp feeds), through to (poultry feeds) up to (stock feeds). The pelletizing of stock feed is done with the pellet mill machinery, which is done in a feed mill. | 0 | Metallurgy |
Battens – the horizontal elements on "board and batten" shutters. Strap hinges usually mount centered on the battens. This is the standard construction approach for most barn doors.
Butt mounted – hinges that mortise into the sides of the hinges – only the barrel of the hinge is visible when the shutter is in the closed position.
Casement – the wood surrounding the window upon which the pintle is typically mounted.
Hinges – mate with the Pintles and are mounted on the shutter.
Pintles – the "pins" on which hinges swing. The pintles are, by definition, mounted to the structure. Pintles are offered in various configurations to match different installation situations.
Rails – with louvered or raised panel shutters, the rails are the horizontal elements of wood that frame the shutter. The width of the rails is an important consideration when choosing surface mounted hardware.
Show hinges – hinges arranged to mount so as to be visible when the shutter is in the open position.
Stiles – when a shutter is louvered or of the raised panel style, the stiles are the vertical elements of the frame. Knowing the width of the stiles allows positioning of the first fastener on strap hinges on their mid-line.
Surface mounted – hinges that mount to the face of the shutter – strap hinges and the "New York Style" hinges are examples. The hinges are visible when the shutter is in the closed position. | 0 | Metallurgy |
Numerous destructive and non-destructive evaluation (NDE) methods exist for characterizing coatings. The most common destructive method is microscopy of a mounted cross-section of the coating and its substrate. The most common non-destructive techniques include ultrasonic thickness measurement, X-ray fluorescence (XRF), X-Ray diffraction (XRD) and micro hardness indentation. X-ray photoelectron spectroscopy (XPS) is also a classical characterization method to investigate the chemical composition of the nanometer thick surface layer of a material. Scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX, or SEM-EDS) allows to visualize the surface texture and to probe its elementary chemical composition. Other characterization methods include transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning tunneling microscope (STM), and Rutherford backscattering spectrometry (RBS). Various methods of Chromatography are also used, as well as thermogravimetric analysis. | 0 | Metallurgy |
Myristoylation is a lipidation modification where a myristoyl group, derived from myristic acid, is covalently attached by an amide bond to the alpha-amino group of an N-terminal glycine residue. Myristic acid is a 14-carbon saturated fatty acid (14:0) with the systematic name of n-tetradecanoic acid. This modification can be added either co-translationally or post-translationally. N-myristoyltransferase (NMT) catalyzes the myristic acid addition reaction in the cytoplasm of cells. This lipidation event is the most common type of fatty acylation and is present in many organisms, including animals, plants, fungi, protozoans and viruses. Myristoylation allows for weak protein–protein and protein–lipid interactions and plays an essential role in membrane targeting, protein–protein interactions and functions widely in a variety of signal transduction pathways. | 1 | Gene expression + Signal Transduction |
There are two primary mTOR inhibitors used in the treatment of human cancers, temsirolimus and everolimus. mTOR inhibitors have found use in the treatment of a variety of malignancies, including renal cell carcinoma (temsirolimus) and pancreatic cancer, breast cancer, and renal cell carcinoma (everolimus). The complete mechanism of these agents is not clear, but they are thought to function by impairing tumour angiogenesis and causing impairment of the G1/S transition. | 1 | Gene expression + Signal Transduction |
In genetics and molecular biology, a corepressor is a molecule that represses the expression of genes. In prokaryotes, corepressors are small molecules whereas in eukaryotes, corepressors are proteins. A corepressor does not directly bind to DNA, but instead indirectly regulates gene expression by binding to repressors.
A corepressor downregulates (or represses) the expression of genes by binding to and activating a repressor transcription factor. The repressor in turn binds to a gene's operator sequence (segment of DNA to which a transcription factor binds to regulate gene expression), thereby blocking transcription of that gene. | 1 | Gene expression + Signal Transduction |
Endoglin (ENG) is a type I membrane glycoprotein located on cell surfaces and is part of the TGF beta receptor complex. It is also commonly referred to as CD105, END, FLJ41744, HHT1, ORW and ORW1. It has a crucial role in angiogenesis, therefore, making it an important protein for tumor growth, survival and metastasis of cancer cells to other locations in the body. | 1 | Gene expression + Signal Transduction |
Gain of function mutation was first discovered in patients with chronic mucocutaneous candidiasis (CMC). This disease is characteristic with its symptoms as persistent infections of the skin, mucosae - oral or genital and nails infections caused by Candida, mostly Candida albicans. CMC may very often result from primary immunodeficiency. Patients with CMC often suffer also with bacterial infections (mostly Staphylococcus aureus), also with infections of the respiratory system and skin. In these patients we can also find viral infections caused mostly by Herpesviridae, that also affect the skin. The mycobacterial infections are often caused by Mycobacterium tuberculosis or environmental bacteria. Very common are also autoimmune symptoms like type 1 diabetes, cytopenia, regression of the thymus or systemic lupus erythematosus. When T-cell deficient, these autoimmune díseases are very common. CMC was also reported as a common symptom in patients with hyper immunoglobulin E syndrome (hyper-IgE) and with autoimmune polyendocrine syndrome type I. There was reported an interleukin 17A role, because of low levels of IL-17A producing T-cells in CMC patients.
With various genomic and genetic methods was discovered, that a heterozygous gain of function mutation of STAT1 is a cause of more than a half CMC cases. This mutation is caused by defect in the coiled-coil domain, domain that binds DNA, N-terminal domain or SH2 domain. Because of this there is increased phosphorylation because of impossible dephosphorylation in nucleus. These processes are dependent on cytokines like interferon alpha or beta, interferon gamma or interleukin 27. As mentioned above, low levels of interleukin 17A were observed, therefore impaired the Th17 polarization of the immune response.
Patients with STAT1 gain of function mutation and CMC poorly or not at all respond to treatment with azole drugs such as Fluconazole, Itraconazole or Posaconazole. Besides common viral and bacterial infections, these patients develop autoimmunities or even carcinomas. It is very complicated to find a treatment because of various symptoms and resistances, inhibitors of JAK/STAT pathway such as Ruxolitinib are being tested and are a possible choice of treatment for these patients. | 1 | Gene expression + Signal Transduction |
De la Pirotechnia is considered to be one of the first printed books on metallurgy to have been published in Europe. It was written in Italian and first published in Venice in 1540. The author was Vannoccio Biringuccio, a citizen of Siena, Italy, who died before it was published. Further editions were published in 1550, 1558, 1559, and 1678, with a (sloppy) French translation by Jacques Vincent being published in 1556, 1572, and 1627. Parts were translated into Latin (by Georgius Agricola), English (Richard Eden; Peter Whitehorn) and Spanish (Bernardo Perez de Vargas) at various times in the 1550s and 1560s, generally without acknowledgement.
The second book on metallurgy, De re metallica, was written in Latin by Georgius Agricola, and published in 1556.
Mining was typically left to professionals, craftsmen and experts who were not eager to share their knowledge. Much experiential knowledge had been accumulated over the course of time. This knowledge was consecutively handed down orally within a small group of technicians and mining overseers. In the Middle Ages these people held the same leading role as the master builders of the great cathedrals, or perhaps also alchemists. It was a small, cosmopolitan elite within which existing knowledge was passed on and further developed but not shared with the outside world. Only a few writers from that time wrote anything about mining itself. Partly, that was because this knowledge was very difficult to access. Most writers also found it simply not worth the effort to write about it. Only after the middle ages did this perception begin to change. With the improved transport and the invention of the printing press knowledge spread much more easily and faster than before. In 1500, the first printed book dedicated to mining engineering, called the Nutzlich Bergbuchleyn (The Useful Little Mining Book") by Ulrich Rulein von Calw, was published. Both De la pirotechnia and De re metallica were translated into English in the 20th century. The translation of Pirotechnia was by Cyril Stanley Smith, a senior chemist on the Manhattan Project, and Martha Teach Gnudi. Both books were illustrated with extensive, beautiful woodcuts.
The majority of the work is devoted to the more technical aspects of metalworking (such as the mining, assaying and smelting of ores), but Biringuccio also provides insights into the humanistic philosophy of the Italian Renaissance. Alchemy is also discussed. | 0 | Metallurgy |
Wastewater pollutants discharged by iron and steel mills includes gasification products such as benzene, naphthalene, anthracene, cyanide, ammonia, phenols and cresols, together with a range of more complex organic compounds known collectively as polycyclic aromatic hydrocarbons (PAH). Treatment technologies include recycling of wastewater; settling basins, clarifiers and filtration systems for solids removal; oil skimmers and filtration; chemical precipitation and filtration for dissolved metals; carbon adsorption and biological oxidation for organic pollutants; and evaporation.
Pollutants generated by other types of smelters varies with the base metal ore. For example, aluminum smelters typically generate fluoride, benzo(a)pyrene, antimony and nickel, as well as aluminum. Copper smelters typically discharge cadmium, lead, zinc, arsenic and nickel, in addition to copper. Lead smelters may discharge antimony, asbestos, cadmium, copper and zinc, in addition to lead. | 0 | Metallurgy |
These techniques employ electric currents to drive or enhance sintering. English engineer A. G. Bloxam registered in 1906 the first patent on sintering powders using direct current in vacuum. The primary purpose of his inventions was the industrial scale production of filaments for incandescent lamps by compacting tungsten or molybdenum particles. The applied current was particularly effective in reducing surface oxides that increased the emissivity of the filaments.
In 1913, Weintraub and Rush patented a modified sintering method which combined electric current with pressure. The benefits of this method were proved for the sintering of refractory metals as well as conductive carbide or nitride powders. The starting boron–carbon or silicon–carbon powders were placed in an electrically insulating tube and compressed by two rods which also served as electrodes for the current. The estimated sintering temperature was 2000 °C.
In the United States, sintering was first patented by Duval d'Adrian in 1922. His three-step process aimed at producing heat-resistant blocks from such oxide materials as zirconia, thoria or tantalia. The steps were: (i) molding the powder; (ii) annealing it at about 2500 °C to make it conducting; (iii) applying current-pressure sintering as in the method by Weintraub and Rush.
Sintering that uses an arc produced via a capacitance discharge to eliminate oxides before direct current heating, was patented by G. F. Taylor in 1932. This originated sintering methods employing pulsed or alternating current, eventually superimposed to a direct current. Those techniques have been developed over many decades and summarized in more than 640 patents.
Of these technologies the most well known is resistance sintering (also called hot pressing) and spark plasma sintering, while electro sinter forging is the latest advancement in this field. | 0 | Metallurgy |
RNA polymerase III appears to be essential for homologous recombinational repair of DNA double-strand breaks. RNA polymerase III catalyzes the formation of a transient RNA-DNA hybrid at double strand breaks, an essential intermediate step in homologous recombination mediated double-strand break repair. This step protects the 3’ overhanging DNA strand from degradation. After the transient RNA-DNA hybrid intermediate is formed, the RNA strand is replaced by the RAD51 protein, which then catalyzes the ssDNA invasion step of homologous recombination. | 1 | Gene expression + Signal Transduction |
Atomic hydrogen diffusing through metals may collect at internal defects like inclusions and laminations and form molecular hydrogen. High pressures may be built up at such locations due to continued absorption of hydrogen leading to blister formation, growth and eventual bursting of the blister. Such hydrogen induced blister cracking has been observed in steels, aluminium alloys, titanium alloys and nuclear structural materials. Metals with low hydrogen solubility (such as tungsten) are more susceptible to blister formation. While in metals with high hydrogen solubility like vanadium, hydrogen prefers to induce stable metal-hydrides instead of bubbles or blisters. | 0 | Metallurgy |
A nonstop mutation, also called a stop-loss variant, is a point mutation that occurs within a stop codon. Nonstop mutations cause the continued translation of an mRNA strand into what should be an untranslated region. Most polypeptides resulting from a gene with a nonstop mutation lose their function due to their extreme length and the impact on normal folding. Nonstop mutations differ from nonsense mutations in that they do not create a stop codon but, instead, delete one. Nonstop mutations also differ from missense mutations, which are point mutations where a single nucleotide is changed to cause replacement by a different amino acid. Nonstop mutations have been linked with many inherited diseases including endocrine disorders, eye disease, and neurodevelopmental disorders. | 1 | Gene expression + Signal Transduction |
This effect is significantly less common in ceramics which are typically more resilient to chemical attack. Although phase changes are common in ceramics under stress these usually result in toughening rather than failure (see Zirconium dioxide). Recent studies have shown that the same driving force for this toughening mechanism can also enhance oxidation of reduced cerium oxide, resulting in slow crack growth and spontaneous failure of dense ceramic bodies. | 0 | Metallurgy |
Crevice corrosion refers to corrosion occurring in occluded spaces such as interstices in which a stagnant solution is trapped and not renewed. These spaces are generally called crevices. Examples of crevices are gaps and contact areas between parts, under gaskets or seals, inside cracks and seams, spaces filled with deposits and under sludge piles. | 0 | Metallurgy |
The limitations of currently available rapalogs have led to new approaches to mTOR targeting. Studies suggest that mTOR inhibitors may have anticancer activity in many cancer types, such as RCC, neuroendocrine tumors, breast cancer, hepatocellular carcinoma, sarcoma, and large B-cell lymphoma.
One major limitation for the development of mTOR inhibition therapy is that biomarkers are not presently available to predict which patient will respond to them. A better understanding of the molecular mechanisms that are involved in the response of cancer cells to mTOR inhibitors are still required so this can be possible.
A way to overcome the resistance and improve efficacy of mTOR targeting agents may be with stratification of patients and selection of drug combination therapies. This may lead to a more effective and personalized cancer therapy. Although further research is needed, mTOR targeting still remains an attractive and promising therapeutic option for the treatment of cancer. | 1 | Gene expression + Signal Transduction |
Carbon in pulp (CIP) is an extraction technique for recovery of gold which has been liberated into a cyanide solution as part of the gold cyanidation process.
Introduced in the early 1980s, Carbon in Pulp is regarded as a simple and cheap process. As such it is used in most industrial applications where the presence of competing silver or copper does not prohibit its use. In the case of high (i.e., 1%) copper content, froth flotation is more typical.
Activated carbon acts like a sponge to dicyanoaurate, the main soluble gold species in gold extraction technologies. Hard carbon particles (much larger than the ore particle sizes) can be mixed with the solution. The gold cyanide complex adsorb onto the carbon and is proposed to be reduced back to the metal. Because the carbon particles are much larger than the ore particles, the coarse carbon can then be separated from the slurry by screening using a wire mesh. | 0 | Metallurgy |
While the Superstack lowered the ground-level pollution in the city, it has dispersed sulphur dioxide, and nitrogen dioxide gases over a much larger area. Though not the single source of lake acidification, it appears even the heavily industrialized Ohio Valley has contributed to the ecological problem of lakes as far north as northern Ontario. Research from data gleaned up to the late 1980s demonstrated acid rain to have affected the biology of some 7,000 lakes.
Prior to Vale's purchase of Inco, a major construction effort by Inco in the early 1990s dramatically scrubbed waste gases before pumping them up the Superstack. These upgrades were completed in 1994 and emissions from then on have been much reduced. By comparison to the plume prior to installation, the plume now disperses quite rapidly and is often see-through even at the stack site.
Emissions reductions and increases in thermal efficiency have reached the point where natural draught is no longer sufficient to draw flue gas up the stack, necessitating the use of induced draught fans and/or reheating of the flue gas using natural gas burners.
In contrast to the reduction of SO emissions, Inco's Superstack stands out in North America in its arsenic, nickel and lead emissions to the atmosphere. Using data compiled by the Commission for Environmental Cooperation, Inco alone accounts for 20% of all of the arsenic emitted in North America, 13% of the lead and 30% of the nickel. Although it is not strictly fair to compare a nickel-copper smelter to a lead smelter, by so doing one can get an idea of how poor the containment of lead is at Copper Cliff. In 1998, Inco emitted 146.7 tonnes of lead at Copper Cliff with a smelter production of 238,500 tonnes of nickel-copper matte. The EPA regulations in the United States require a primary lead smelter to limit emissions of lead to 3.0 gm per tonne of product. With this emission factor, Copper Cliff would be required to limit emissions of lead to approximately 1 tonne per year, demonstrating that the actual emission is about 150 times greater than allowed by US regulations for a lead smelter. Even with the 85% reduction postulated by Hatch, Inco would still emit 10 tonnes per year of lead, or four times the amount allowed by the EPA for a lead smelter.
As a result of the excessive lead emissions from the Inco Superstack, the surrounding community of Copper Cliff was found to have levels of lead in soil tests at a level sufficient to cause harm to young children. | 0 | Metallurgy |
By the early 19th century the puddling process was widespread. Until technological advances made it possible to work at higher heats, slag impurities could not be removed entirely, but the reverberatory furnace made it possible to heat iron without placing it directly in the fire, offering some degree of protection from the impurity of the fuel source. Thus, with the advent of this technology, coal began to replace charcoal fuel. The Bessemer process allowed steel to be produced without fuel, using the impurities of the iron to create the necessary heat. This drastically reduced the costs of steel production, but raw materials with the required characteristics could be difficult to find.
High-quality steel was made by the reverse process of adding carbon to carbon-free wrought iron, usually imported from Sweden. The manufacturing process, called the cementation process, consisted of heating bars of wrought iron together with charcoal for periods of up to a week in a long stone box. This produced blister steel. The blister steel was put in a crucible with wrought iron and melted, producing crucible steel. Up to 3 tons of expensive coke was burnt for each ton of steel produced. Such steel when rolled into bars was sold at £50 to £60 (approximately £3,390 to £4,070 in 2008) a long ton. The most difficult and work-intensive part of the process, however, was the production of wrought iron done in finery forges in Sweden.
This process was refined in the 18th century with the introduction of Benjamin Huntsman's crucible steel-making techniques, which added an additional three hours firing time and required additional large quantities of coke. In making crucible steel, the blister steel bars were broken into pieces and melted in small crucibles, each containing 20 kg or so. This produced higher quality crucible steel but increased the cost. The Bessemer process reduced the time needed to make lower-grade steel to about half an hour while requiring only the coke needed initially to melt the pig iron. The earliest Bessemer converters produced steel for £7 a long ton, although it initially sold for around £40 a ton. | 0 | Metallurgy |
A typical thermal spray system consists of the following:
*Spray torch (or spray gun) – the core device performing the melting and acceleration of the particles to be deposited
*Feeder – for supplying the powder, wire or liquid to the torch through tubes.
*Media supply – gases or liquids for the generation of the flame or plasma jet, gases for carrying the powder, etc.
*Robot/Labour – for manipulating the torch or the substrates to be coated
*Power supply – often standalone for the torch
*Control console(s) – either integrated or individual for all of the above | 0 | Metallurgy |
Ethylene signaling pathway is a signal transduction in plant cells to regulate important growth and developmental processes. Acting as a plant hormone, the gas ethylene is responsible for promoting the germination of seeds, ripening of fruits, the opening of flowers, the abscission (or shedding) of leaves and stress responses. It is the simplest alkene gas and the first gaseous molecule discovered to function as a hormone.
Most of the understanding on ethylene signal transduction come from studies on Arabidopsis thaliana. Ethylene can bind to at least five different membrane receptors. Although structurally diverse, the ethylene receptors all exhibit similarity (homology) to two-component regulatory system in bacteria, indicating their common ancestry from bacterial ancestor. Ethylene binds to the receptors on the cell membrane of the endoplasmic reticulum. Although homodimers of the receptors are required for functional state, only one ethylene molecule binds to each dimer.
Unlike in other signal transductions, ethylene is the suppressor of its receptor activity. Ethylene receptors are active without ethylene due to binding with other enzymatically active co-receptors such as constitutive triple response 1 (CTR1) and ethylene insensitive 2 (EIN2). Ethylene binding causes EIN2 to split in two, of which the C-terminal portion of the protein can activate different transcription factors to bring about the effects of ethylene. There is also non-canonical pathway in which ethylene activates cytokinin receptor, and thereby regulate seed development (stomatal aperture) and growth of root (the apical meristem). | 1 | Gene expression + Signal Transduction |
New mTOR-specific inhibitors came forth from screening and drug discovery efforts. These compounds block activity of both mTOR complexes and are called mTORC1/mTORC2 dual inhibitors. Compounds with this characteristics such as sapanisertib (codenamed INK128), AZD8055, and AZD2014 have entered clinical trials.
A series of these mTOR kinase inhibitors have been studied. Their structure is derived from morpholino pyrazolopyrimidine scaffold.
Improvements of this type of inhibitors have been made by exchanging the morpholines with bridged morpholines in pyrazolopyrimidine inhibitors and results showed increased selectivity to mTOR by 26000 fold. | 1 | Gene expression + Signal Transduction |
Gold, copper and tumbaga objects started being produced in Panama and Costa Rica between 300–500 CE. Open-molded casting with oxidation gilding and cast filigrees were in use. By 700–800 CE, small metal sculptures were common and an extensive range of gold and tumbaga ornaments constituted the usual regalia of persons of high status in Panama and Costa Rica.
The earliest specimen of metalwork from the Caribbean is a gold-alloy sheet carbon dated to 70–374 CE. Most Caribbean metallurgy has been dated to between 1200 and 1500 CE and consists of simple, small pieces such as sheets, pendants, beads and bells. These are mostly gold or a gold alloy (with copper or silver) and have been found to be largely cold hammered and sand-polished alluvial nuggets, although a few items seem to have been produced by lost wax casting. It is presumed that at least some of these items were acquired by trade from Colombia. | 0 | Metallurgy |
In the process of smelting, inorganic chlorides, fluorides (see fluorite), limestone and other materials are designated as "fluxes" when added to the contents of a smelting furnace or a cupola for the purpose of purging the metal of chemical impurities such as phosphorus, and of rendering slag more liquid at the smelting temperature. Slag is a liquid mixture of ash, flux, and other impurities. This reduction of slag viscosity with temperature, increasing the flow of slag in smelting, is the origin of the word flux in metallurgy.
The flux most commonly used in iron and steel furnaces is limestone, which is charged in the proper proportions with the iron and fuel. | 0 | Metallurgy |
A mechanism involving arbitrium has recently been described in bacteriophages infecting several Bacillus species. The viruses communicate with each other to ascertain their own density compared to potential hosts. They use this information to decide whether to enter a lytic or lysogenic life-cycle.This decision is crucial as it affects their replication strategy and potential to spread within the host population, optimizing their survival and proliferation under varying environmental conditions. This communication mechanism enables a coordinated infection strategy, significantly enhancing the efficiency of phage proliferation. By synchronizing their life cycles, bacteriophages can maximize their impact on the host population, potentially leading to more effective control of bacterial densities. | 1 | Gene expression + Signal Transduction |
Copper tubes have been used to distribute potable water within building for many years and hundreds of miles are installed throughout Europe every year. The long life of copper when exposed to natural waters is a result of its thermodynamic stability, its high resistance to reacting with the environment, and the formation of insoluble corrosion products that insulate the metal from the environment. The corrosion rate of copper in most potable waters is less than 2.5 µm/year, at this rate a 15 mm tube with a wall thickness of 0.7 mm would last for about 280 years. In some soft waters the general corrosion rate may increase to 12.5 µm/year, but even at this rate it would take over 50 years to perforate the same tube. Despite the reliability of copper and copper alloys, in some cold hard waters pits may form in the bore of a tube. If these pits form, failure times can be expected between 6 months and 2 years from initiation. The mechanism that leads to the pitting of copper in cold hard waters is complex, it requires a water with a specific chemistry that is capable of supporting pit growth and a mechanism for the initiation of the pits. | 0 | Metallurgy |
The possibility has been proposed and studied, both theoretically and experimentally, of implementing an orthogonal system inside cells independent of the cellular genetic material in order to make a completely safe system, with the possible increase in encoding potentials.
Several groups have focused on different aspects:
* Novel backbones and base pairs as discussed above;
* XNA artificial replication and transcription polymerases starting generally from T7 RNA polymerase;
* (16S ribosomal sequences with altered anti-Shine-Dalgarno sequences allowing the translation of only orthogonal mRNA with a matching altered Shine-Dalgarno sequence; and
* Novel tRNA encoding non-natural aminoacids for an expanded genetic code. | 1 | Gene expression + Signal Transduction |
The first computational model of dendritic solidification was published by Kobayashi, who used a phase-field model to solve two coupled partial differential equations describing the evolution of the phase-field, (with in the liquid phase and in the solid phase), and the temperature field, , for a pure material in two dimensions:
which is an Allen-Cahn equation with an anisotropic gradient energy coefficient:
where is an average value of , is the angle between the interface normal and the x-axis, and and are constants representing the strength and mode of anisotropy, respectively.
The parameter describes the thermodynamic driving force for solidification, which Kobayashi defines for a supercooled melt as:
where is a constant between 0 and 1, is a positive constant, and is the dimensionless equilibrium temperature. The temperature has been non-dimensionalized such that the equilibrium temperature is and the initial temperature of the undercooled melt is .
The evolution equation for the temperature field is given by
and is simply the heat equation with a source term due to the evolution of latent heat upon solidification, where is a constant representing the latent heat normalized by the strength of the cooling.
When this system is numerically evolved, random noise representing thermal fluctuations is introduced to the interface via the term, where is the magnitude of the noise and is a random number distributed uniformly on . | 0 | Metallurgy |
A prill is a small aggregate or globule of a material, most often a dry sphere, formed from a melted liquid through spray crystallization. Prilled is a term used in mining and manufacturing to refer to a product that has been pelletized. ANFO explosive typically comprises ammonium nitrate prills mixed with #2 fuel oil. The pellets are a neater, simpler form for handling, with reduced dust.
The material to be prilled must be in a solid state at room temperature and a low-viscosity liquid when melted. Prills are formed by allowing drops of the melted prill substance to congeal or freeze in mid-air after being dripped from the top of a tall prilling tower. Certain agrochemicals such as urea are often supplied in prilled form. Fertilizers (ammonium nitrate, urea, NPK fertilizer) and some detergent powders are commonly manufactured as prills. However prilling of ammonium nitrate and urea has in recent years been replaced by fluid bed granulation as this gives strong and more abrasion-resistant granules.
Melted material may also be atomized and then allowed to form smaller prills that are useful in cosmetics, food, and animal feed. | 0 | Metallurgy |