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Metal-induced embrittlement (MIE) is the embrittlement caused by diffusion of metal, either solid or liquid, into the base material. Metal induced embrittlement occurs when metals are in contact with low-melting point metals while under tensile stress. The embrittler can be either solid (SMIE) or liquid (liquid metal embrittlement). Under sufficient tensile stress, MIE failure occurs instantaneously at temperatures just above melting point. For temperatures below the melting temperature of the embrittler, solid-state diffusion is the main transport mechanism. This occurs in the following ways:
* Diffusion through grain boundaries near the crack of matrix
* Diffusion of first monolayer heterogeneous surface embrittler atoms
* Second monolayer heterogenous surface diffusion of embrittler
* Surface diffusion of the embrittler over a layer of embrittler
The main mechanism of transport for SMIE is surface self-diffusion of the embrittler over a layer of embrittler that’s thick enough to be characterized as self-diffusion at the crack tip. In comparison, LMIE dominant mechanism is bulk liquid flow that penetrates at the tips of cracks. | 0 | Metallurgy |
The iron pillar of Dhar was originally longer than the iron pillar of Delhi. After the Muslim conquest of Dhar, it broke into at least two pieces. The smaller piece was planted at the Dilawar Khan's Mosque in Mandu. The larger piece was erected in front of the Lat Masjid constructed by Dilawar Khan in 1405.
In 1531 CE, Dhar came under the control of Bahadur Shah, the Sultan of Gujarat. He made an attempt to carry the large piece to Gujarat. In this process, this part of the pillar toppled and fragmented into two pieces.
Now, three fragments of the pillar are placed horizontally on a platform near Lat Masjid. These fragments were moved by ASI to their present position in 1980. The combined height of the three fragments is , and their total weight is estimated at . Thus, the original pillar must have been almost twice as high and at least heavier than the iron pillar of Delhi. At the time of its erection, it was probably the tallest and the largest forge-welded iron pillar in the world. | 0 | Metallurgy |
The bacterial RNA polymerase, a leading enzyme involved in formation of a transcription bubble, uses DNA template to guide RNA synthesis. It is present in two main forms: as a core enzyme, when it is inactive, and as a holoenzyme, when it is activated. A sigma (σ) factor is a subunit that assists the process of transcription and it stabilizes the transcription bubble when it binds to unpaired bases. These two components, RNA polymerase and sigma factor, when paired together, build RNA polymerase holoenzyme which is then in its active form and ready to bind to a promoter and initiate DNA transcription. Once it binds to the DNA, RNA polymerase turns from a closed to an open complex, forming the transcription bubble. RNA polymerase synthesizes the new RNA in the 5 to 3 direction by adding complementary bases to the 3' end of a new strand. The holoenzyme composition dissociates after transcription initiation, where the σ factor disengages the complex and the RNA polymerase, in its core form, slides along the DNA molecule. | 1 | Gene expression + Signal Transduction |
Transcription factors are proteins that bind to specific DNA sequences in order to regulate the expression of a given gene. There are approximately 1,400 transcription factors in the human genome and they constitute about 6% of all human protein coding genes. The power of transcription factors resides in their ability to activate and/or repress wide repertoires of downstream target genes. The fact that these transcription factors work in a combinatorial fashion means that only a small subset of an organism's genome encodes transcription factors.
Transcription factors function through a wide variety of mechanisms. In one mechanism, CpG methylation influences binding of most transcription factors to DNA—in some cases negatively and in others positively. In addition, often they are at the end of a signal transduction pathway that functions to change something about the factor, like its subcellular localization or its activity. Post-translational modifications to transcription factors located in the cytosol can cause them to translocate to the nucleus where they can interact with their corresponding enhancers. Other transcription factors are already in the nucleus, and are modified to enable the interaction with partner transcription factors. Some post-translational modifications known to regulate the functional state of transcription factors are phosphorylation, acetylation, SUMOylation and ubiquitylation.
Transcription factors can be divided in two main categories: activators and repressors. While activators can interact directly or indirectly with the core machinery of transcription through enhancer binding, repressors predominantly recruit co-repressor complexes leading to transcriptional repression by chromatin condensation of enhancer regions. It may also happen that a repressor may function by allosteric competition against a determined activator to repress gene expression: overlapping DNA-binding motifs for both activators and repressors induce a physical competition to occupy the site of binding. If the repressor has a higher affinity for its motif than the activator, transcription would be effectively blocked in the presence of the repressor.
Tight regulatory control is achieved by the highly dynamic nature of transcription factors. Again, many different mechanisms exist to control whether a transcription factor is active. These mechanisms include control over protein localization or control over whether the protein can bind DNA. An example of this is the protein HSF1, which remains bound to Hsp70 in the cytosol and is only translocated into the nucleus upon cellular stress such as heat shock. Thus the genes under the control of this transcription factor will remain untranscribed unless the cell is subjected to stress. | 1 | Gene expression + Signal Transduction |
*Pleiner, R. (2000) Iron in Archaeology. The European Bloomery Smelters, Praha, Archeologický Ústav Av Cr.
*Veldhuijzen, H.A. (2005) Technical Ceramics in Early Iron Smelting. The Role of Ceramics in the Early First Millennium Bc Iron Production at Tell Hammeh (Az-Zarqa), Jordan. In: Prudêncio, I.Dias, I. and Waerenborgh, J.C. (Eds.) Understanding People through Their Pottery; Proceedings of the 7th European Meeting on Ancient Ceramics (Emac 03)'. Lisboa, Instituto Português de Arqueologia (IPA).
*Veldhuijzen, H.A. and Rehren, Th. (2006) Iron Smelting Slag Formation at Tell Hammeh (Az-Zarqa), Jordan. In: Pérez-Arantegui, J. (Ed.) Proceedings of the 34th International Symposium on Archaeometry, Zaragoza, 3–7 May 2004. Zaragoza, Institución «Fernando el Católico» (C.S.I.C.) Excma. Diputación de Zaragoza. | 0 | Metallurgy |
There are also several pyrometallurgical processes that reduce zinc oxide using carbon, then distil the metallic zinc from the resulting mix in an atmosphere of carbon monoxide. The major downfall of any of the pyrometallurgical process is that it is only 98% pure; a standard composition is 1.3% lead, 0.2% cadmium, 0.03% iron, and 98.5% zinc. This may be pure enough for galvanization, but not enough for die casting alloys, which requires special high-grade zinc (99.995% pure). In order to reach this purity the zinc must be refined.
The four types of commercial pyrometallurgical processes are the St. Joseph Minerals Corporations (electrothermic) process, the blast furnace process, the New Jersey Zinc continuous vertical-retort process, and the Belgian-type horizontal retort' process. | 0 | Metallurgy |
Metal sulfides (e.g., pyrite FeS, arsenopyrite FeAsS, chalcopyrite CuFeS) are normally processed by chemical oxidation either in aqueous media or at high temperatures. In fact, most base metals, e.g., aluminium, chromium, must be (electro)chemically reduced at high temperatures by which the process entails a high energy demand, and sometimes large volumes of aqueous waste is generated. In aqueous media chalcopyrite, for instance, is more difficult to dissolve chemically than covellite and chalcocite due to surface effects (formation of polysulfide species,). The presence of Cl ions has been suggested to alter the morphology of any sulfide surface formed, allowing the sulfide mineral to leach more easily by preventing passivation. DESs provide a high Cl ion concentration and low water content, whilst reducing the need for either high additional salt or acid concentrations, circumventing most oxide chemistry. Thus, the electrodissolution of sulfide minerals has demonstrated promising results in DES media in absence of passivation layers, with the release into the solution of metal ions which could be recovered from solution.
During extraction of copper from copper sulfide minerals with Ethaline, chalcocite (CuS) and covellite (CuS) produce a yellow solution, indicating that [CuCl] complex are formed. Meanwhile, in the solution formed from chalcopyrite, Cu and Cu species co-exist in solution due to the generation of reducing Fe species at the cathode. The best selective recovery of copper (>97%) from chalcopyrite can be obtained with a mixed DES of 20 wt.% ChCl-oxalic acid and 80 wt.% Ethaline. | 0 | Metallurgy |
The function of this intron in the vectors is unknown, but it is theorized that it might be involved in splicing or translation efficiency.
Vectors such as pME18s contain it. | 1 | Gene expression + Signal Transduction |
A thermocouple can produce current to drive some processes directly, without the need for extra circuitry and power sources. For example, the power from a thermocouple can activate a valve when a temperature difference arises. The electrical energy generated by a thermocouple is converted from the heat which must be supplied to the hot side to maintain the electric potential. A continuous transfer of heat is necessary because the current flowing through the thermocouple tends to cause the hot side to cool down and the cold side to heat up (the Peltier effect).
Thermocouples can be connected in series to form a thermopile, where all the hot junctions are exposed to a higher temperature and all the cold junctions to a lower temperature. The output is the sum of the voltages across the individual junctions, giving larger voltage and power output. In a radioisotope thermoelectric generator, the radioactive decay of transuranic elements as a heat source has been used to power spacecraft on missions too far from the Sun to use solar power.
Thermopiles heated by kerosene lamps were used to run batteryless radio receivers in isolated areas. There are commercially produced lanterns that use the heat from a candle to run several light-emitting diodes, and thermoelectrically powered fans to improve air circulation and heat distribution in wood stoves. | 0 | Metallurgy |
* NSCLC (48% of investigated cell lines)
* SCLC (38% of investigated cell lines)
* Bladder cancers (38%)
* Breast cancers (46%)
* Malignant mesotheliomas (48%)
* Colorectal cancers (76%) | 1 | Gene expression + Signal Transduction |
As with all gene therapies, a number of safety and toxicity issues need to be evaluated during the development of DDRNAI therapeutics.
Oncogene activation by viral insertion: Some gene therapy vectors integrate into the host genome, thereby acting as insertional mutagens. This was a particular issue with early retroviral vectors where insertions adjacent to oncogenes resulted in the development of lymphoid tumors. AAV vectors are considered low-risk for host-genome integration, as adeno-associated virus infection has not been associated with the induction of cancers in humans despite widespread prevalence across the general population. Moreover, extensive clinical use of AAV vectors has provided no evidence of carcinogenicity. While lentiviral vectors do integrate into the genome they do not appear to show a propensity to activate oncogene expression.
Immune response to gene therapy vectors: An immunological response to an adenoviral vector resulted in the death of a patient in an early human trial. Careful monitoring of potential toxicities in preclinical testing and analyses of pre-existing antibodies to gene therapy vectors in patients minimizes such risks.
Innate immune response: siRNAs have been shown to activate immune responses through interaction with Toll-like receptors leading to interferon responses. These receptors reside on the cell's surface and so DDRNAIconstructs – delivered directly into intracellular space – are not expected to induce this response.
Toxic effects due to over-expression of shRNAs: High-level expression of shRNAs has been shown to be toxic. Strategies to minimize levels of shRNA expression or promote precise processing of shRNAs can overcome this problem.
Off-target effects: Unintended silencing of genes that share sequence homology with expressed shRNAs can theoretically occur. Careful selection of shRNA sequences and thorough preclinical testing of constructs can circumvent this issue. | 1 | Gene expression + Signal Transduction |
The gal operon is a prokaryotic operon, which encodes enzymes necessary for galactose metabolism. Repression of gene expression for this operon works via binding of repressor molecules to two operators. These repressors dimerize, creating a loop in the DNA. The loop as well as hindrance from the external operator prevent RNA polymerase from binding to the promoter, and thus prevent transcription. Additionally, since the metabolism of galactose in the cell is involved in both anabolic and catabolic pathways, a novel regulatory system using two promoters for differential repression has been identified and characterized within the context of the gal operon. | 1 | Gene expression + Signal Transduction |
Austenite is only stable above in bulk metal form. However, fcc transition metals can be grown on a face-centered cubic (fcc) or diamond cubic. The epitaxial growth of austenite on the diamond (100) face is feasible because of the close lattice match and the symmetry of the diamond (100) face is fcc. More than a monolayer of γ-iron can be grown because the critical thickness for the strained multilayer is greater than a monolayer. The determined critical thickness is in close agreement with theoretical prediction. | 0 | Metallurgy |
One way to identify the expression pattern of a particular gene is to place a reporter gene downstream of its promoter. In this configuration, the promoter gene will cause the reporter gene to be expressed only where and when the gene of interest is expressed. The expression distribution of the reporter gene can be determined by visualizing it. For example, the reporter gene green fluorescent protein can be visualized by stimulating it with blue light and then using a digital camera to record green fluorescent emission.
If the promoter of the gene of interest is unknown, there are several ways to identify its spatiotemporal distribution. Immunohistochemistry involves preparing an antibody with specific affinity for the protein associated with the gene of interest. This distribution of this antibody can then be visualized by a technique such as fluorescent labeling. Immunohistochemistry has the advantages of being methodologically feasible and relatively inexpensive. Its disadvantages include non-specificity of the antibody leading to false positive identification of expression. Poor penetrance of the antibody into the target tissue can lead to false negative results. Furthermore, since immunohistochemistry visualizes the protein generated by the gene, if the protein product diffuses between cells, or has a particularly short or long half-life relative to the mRNA that is used to translate the protein, this can lead to distorted interpretation of which cells are expressing the mRNA.
In situ hybridization is an alternate method in which a "probe," a synthetic nucleic acid with a sequence complementary to the mRNA of the gene, is added to the tissue. This probe is then chemically tagged so that it can be visualized later. This technique enables visualization specifically of mRNA-producing cells without any of the artifacts associated with immunohistochemistry. However, it is notoriously difficult, and requires knowledge of the sequence of DNA corresponding to the gene of interest.
A method called enhancer-trap screening reveals the diversity of spatiotemporal gene expression patterns possible in an organism. In this technique, DNA that encodes a reporter gene is randomly inserted into the genome. Depending on the gene promoters proximal to the insertion point, the reporter gene will be expressed in particular tissues at particular points in development. While enhancer-trap derived expression patterns do not necessarily reflect the actual patterns of expression of specific genes, they reveal the variety of spatiotemporal patterns that are accessible to evolution.
Reporter genes can be visualized in living organisms, but both immunohistochemistry and in situ hybridization must be performed in fixed tissues. Techniques that require fixation of tissue can only generate a single temporal time point per individual organism. However, using live animals instead of fixed tissue can be crucial in dynamically understanding expression patterns over an individual's lifespan. Either way, variation between individuals can confound the interpretation of temporal expression patterns. | 1 | Gene expression + Signal Transduction |
The first known smelting of iron began in Anatolia, around 1800 BC. Called the bloomery process, it produced very soft but ductile wrought iron. By 800 BC, iron-making technology had spread to Europe, arriving in Japan around 700 AD. Pig iron, a very hard but brittle alloy of iron and carbon, was being produced in China as early as 1200 BC, but did not arrive in Europe until the Middle Ages. Pig iron has a lower melting point than iron, and was used for making cast-iron. However, these metals found little practical use until the introduction of crucible steel around 300 BC. These steels were of poor quality, and the introduction of pattern welding, around the 1st century AD, sought to balance the extreme properties of the alloys by laminating them, to create a tougher metal. Around 700 AD, the Japanese began folding bloomery-steel and cast-iron in alternating layers to increase the strength of their swords, using clay fluxes to remove slag and impurities. This method of Japanese swordsmithing produced one of the purest steel-alloys of the ancient world.
While the use of iron started to become more widespread around 1200 BC, mainly because of interruptions in the trade routes for tin, the metal was much softer than bronze. However, very small amounts of steel, (an alloy of iron and around 1% carbon), was always a byproduct of the bloomery process. The ability to modify the hardness of steel by heat treatment had been known since 1100 BC, and the rare material was valued for the manufacture of tools and weapons. Because the ancients could not produce temperatures high enough to melt iron fully, the production of steel in decent quantities did not occur until the introduction of blister steel during the Middle Ages. This method introduced carbon by heating wrought iron in charcoal for long periods of time, but the absorption of carbon in this manner is extremely slow thus the penetration was not very deep, so the alloy was not homogeneous. In 1740, Benjamin Huntsman began melting blister steel in a crucible to even out the carbon content, creating the first process for the mass production of tool steel. Huntsman's process was used for manufacturing tool steel until the early 1900s.
The introduction of the blast furnace to Europe in the Middle Ages meant that people could produce pig iron in much higher volumes than wrought iron. Because pig iron could be melted, people began to develop processes to reduce carbon in liquid pig iron to create steel. Puddling had been used in China since the first century, and was introduced in Europe during the 1700s, where molten pig iron was stirred while exposed to the air, to remove the carbon by oxidation. In 1858, Henry Bessemer developed a process of steel-making by blowing hot air through liquid pig iron to reduce the carbon content. The Bessemer process led to the first large scale manufacture of steel.
Steel is an alloy of iron and carbon, but the term alloy steel usually only refers to steels that contain other elements— like vanadium, molybdenum, or cobalt—in amounts sufficient to alter the properties of the base steel. Since ancient times, when steel was used primarily for tools and weapons, the methods of producing and working the metal were often closely guarded secrets. Even long after the Age of Enlightenment, the steel industry was very competitive and manufacturers went through great lengths to keep their processes confidential, resisting any attempts to scientifically analyze the material for fear it would reveal their methods. For example, the people of Sheffield, a center of steel production in England, were known to routinely bar visitors and tourists from entering town to deter industrial espionage. Thus, almost no metallurgical information existed about steel until 1860. Because of this lack of understanding, steel was not generally considered an alloy until the decades between 1930 and 1970 (primarily due to the work of scientists like William Chandler Roberts-Austen, Adolf Martens, and Edgar Bain), so "alloy steel" became the popular term for ternary and quaternary steel-alloys.
After Benjamin Huntsman developed his crucible steel in 1740, he began experimenting with the addition of elements like manganese (in the form of a high-manganese pig-iron called spiegeleisen), which helped remove impurities such as phosphorus and oxygen; a process adopted by Bessemer and still used in modern steels (albeit in concentrations low enough to still be considered carbon steel). Afterward, many people began experimenting with various alloys of steel without much success. However, in 1882, Robert Hadfield, being a pioneer in steel metallurgy, took an interest and produced a steel alloy containing around 12% manganese. Called mangalloy, it exhibited extreme hardness and toughness, becoming the first commercially viable alloy-steel. Afterward, he created silicon steel, launching the search for other possible alloys of steel.
Robert Forester Mushet found that by adding tungsten to steel it could produce a very hard edge that would resist losing its hardness at high temperatures. "R. Mushets special steel" (RMS) became the first high-speed steel. Mushets steel was quickly replaced by tungsten carbide steel, developed by Taylor and White in 1900, in which they doubled the tungsten content and added small amounts of chromium and vanadium, producing a superior steel for use in lathes and machining tools. In 1903, the Wright brothers used a chromium-nickel steel to make the crankshaft for their airplane engine, while in 1908 Henry Ford began using vanadium steels for parts like crankshafts and valves in his Model T Ford, due to their higher strength and resistance to high temperatures. In 1912, the Krupp Ironworks in Germany developed a rust-resistant steel by adding 21% chromium and 7% nickel, producing the first stainless steel. | 0 | Metallurgy |
Promoters can be very closely located in the DNA. Such "closely spaced promoters" have been observed in the DNAs of all life forms, from humans to prokaryotes and are highly conserved. Therefore, they may provide some (presently unknown) advantages.
These pairs of promoters can be positioned in divergent, tandem, and convergent directions. They can also be regulated by transcription factors and differ in various features, such as the nucleotide distance between them, the two promoter strengths, etc.
The most important aspect of two closely spaced promoters is that they will, most likely, interfere with each other. Several studies have explored this using both analytical and stochastic models. There are also studies that measured gene expression in synthetic genes or from one to a few genes controlled by bidirectional promoters.
More recently, one study measured most genes controlled by tandem promoters in E. coli. In that study, it was measured and then modeled two main forms of interference. One is when an RNAP is on the downstream promoter, blocking the movement of RNAPs elongating from the upstream promoter. The other is when the two promoters are so close that when an RNAP sits on one of the promoters, it blocks any other RNAP from reaching the other promoter. These events are possible because the RNAP occupies several nucleotides when bound to the DNA, including in transcription start sites.
Similar events occur when the promoters are in divergent and convergent formations. The possible events also depend on the distance between them. | 1 | Gene expression + Signal Transduction |
The electrical conduction system of the heart has been robustly established. However, newer research has been challenging some of the previously accepted models. The role of ephaptic coupling in cardiac cells is becoming more apparent. One author even goes so far as to say, “While previously viewed as a possible alternative to electrotonic coupling, ephaptic coupling has since come to be viewed as operating in tandem with gap junctions, helping sustain conduction when gap junctional coupling is compromised.” Ephaptic interactions among cardiac cells help fill in the gaps that electrical synapses alone cannot account for. The proximity of sodium channels to gap junction plaques has been shown to relate to their effectiveness in driving ephaptic coupling action potential transmission. There are also a number of mathematical models that now incorporate ephaptic coupling into predictions about electrical conductance in the heart. Experimental work suggests that sodium channel-rich nanodomains located at sites of close contact between cardiac myocytes may constitute functional units of ephaptic coupling and selective disruption of these nanodomains resulted in arrhythmogenic conduction slowing, suggesting an important role for ephaptic coupling in the heart. Potential ephaptic connections are now being considered in heart therapeutics. | 1 | Gene expression + Signal Transduction |
Seizures are characterized by high levels of synchronized neuronal activity. One important regulator of neuronal activity is the hyperpolarizing A-type current mediated by potassium channel KV4.2. miR-324-5p downregulates KV4.2, exacerbating conditions that lead to seizure onset, and downregulation of miR-324-5p in mouse models of epilepsy is seizure-suppressive.
Changes in miRNA expression are seen in epileptogenesis and in other disease pathologies. In epilepsy, miR-324-5p expression has been shown to increase and decrease at different timepoints and loci.
Importantly, miR-324-5p has increased association with the RISC complex following seizure in mice, indicating more suppressive activity.
Overall, this suggests that miR-324-5p plays a role in epileptogenesis via targeting of potassium channel KV4.2. | 1 | Gene expression + Signal Transduction |
CKLF like MARVEL transmembrane domain-containing 6 (i.e. CMTM6), previously termed chemokine-like factor superfamily 6 (i.e. CKLFSF6), is a transmembrane protein encoded in humans by the CMTM6 gene (also termed the CKLFSF6, PRO2219, ayoube, or gourari gene). This gene is located in band 22.3 on the short (or "p") arm of chromosome 3. CMTM6 protein belongs to the CKLF-like MARVEL transmembrane domain-containing family of proteins. This family consist of 9 member proteins: CKLF and CMTM1 through CMTM8. The CMTM family proteins are involved in autoimmune diseases, cardiovascular diseases, the male reproductive system, haematopoiesis, and cancer development. CMTM6 protein regulates immune responses to normal and abnormal (particularly cancerous) cells. | 1 | Gene expression + Signal Transduction |
Generally, in progression to cancer, hundreds of genes are silenced or activated. Although silencing of some genes in cancers occurs by mutation, a large proportion of carcinogenic gene silencing is a result of altered DNA methylation (see DNA methylation in cancer). DNA methylation causing silencing in cancer typically occurs at multiple CpG sites in the CpG islands that are present in the promoters of protein coding genes.
Altered expressions of microRNAs also silence or activate many genes in progression to cancer (see microRNAs in cancer). Altered microRNA expression occurs through hyper/hypo-methylation of CpG sites in CpG islands in promoters controlling transcription of the microRNAs.
Silencing of DNA repair genes through methylation of CpG islands in their promoters appears to be especially important in progression to cancer (see methylation of DNA repair genes in cancer). | 1 | Gene expression + Signal Transduction |
In order to isolate noble-metalliferous materials, pyrolysis and/or hydrolysis procedures are used. In pyrolysis, the noble-metalliferous products are released from the other materials by solidifying in a melt to become cinder and then poured off or oxidized. In hydrolysis, the noble-metalliferous products are dissolved either in aqua regia (consisting of hydrochloric acid and nitric acid) or in hydrochloric acid and chlorine gas in solution. Subsequently, certain metals can be precipitated or reduced directly with a salt, gas, organic, and/or nitro hydrate connection. Afterwards, they go through cleaning stages or are recrystallized. The precious metals are separated from the metal salt by calcination. The noble-metalliferous materials are hydrolyzed first and thermally prepared (pyrolysed) thereafter. The processes are better yielding when using catalysts that may sometimes contain precious metals themselves. When using catalysts, the recycling product is removed in each case and driven several times through the cycle. | 0 | Metallurgy |
There's evidence of very early metallurgy at Aratashen, going back to the first half of the sixth millennium BCE. According to A. Courcier,
At Aratashen and Khatunakh/Aknashen, there are similarities to the contemporary sites of Kultepe I, and Alikemek-Tepesi. Another prehistoric site that is close to Aratashen is Masis Blur. | 0 | Metallurgy |
It has been observed that the development of hormone resistance in prostate cancer may be due to the upregulation of antiapoptotic genes, one of which is survivin.
Zhang et al. hypothesize that, if survivin is a significant contributor to the development of hormonal therapy resistance in prostate cancer cells, targeting survivin and blocking it would enhance prostate cancer cell susceptibility to anti-androgen therapy. (Anti-androgen therapy uses drugs to eliminate the presence of androgens in the cell and cellular environment, since such androgens are known to enhance tumour immortality in prostate cancer cells.) Zhang et al. first assessed the level of survivin expression of LNCaP (an androgen-dependent prostate cancer cell line that expresses intact androgen receptors) using quantitative Western analysis and found high expression of survivin in these cells. Cells exposed to dihydrotestosterone (DHT) showed increased levels of survivin expression only and not other IAP family members. This result suggests that androgens may upregulate survivin, which contributes to the resistance to apoptosis observed in the tumour cells. Next, with the addition of flutamide (an antiandrogen) to the cells, survivin levels were observed to significantly decrease. The LNCaP cells were transduced separately with the different constructs of the survivin gene (mutant or wild-type) and subjected to flutamide treatment and assessed for the apoptosis level. Flutamide-treated survivin mutant-transduced cells were shown to significantly increase apoptosis by double that of flutamide treatment alone. On the other end, overexpression of the wild-type survivin was found to significantly reduce the apoptosis levels from flutamide treatment compared to flutamide treatment alone. Therefore, these results support the hypothesis that survivin plays a role in the anti-apoptotic nature of the LNCaP cancer cell line and that inhibiting survivin in prostate cancer cells appears to enhance the therapeutic effect of flutamide. | 1 | Gene expression + Signal Transduction |
At lower temperatures, about 400–450 °C, an interdiffusion process takes place at the junction, leading to formation of layers of different gold-aluminum intermetallic compounds with different growth rates. Gaps are formed as the denser and faster-growing layers consume the slower-growing layers. This process is known as the Kirkendall voiding, which leads to both increased electrical resistance and mechanical weakening of the wire bond. When the voids forms along the diffusion front, this process is aided by contaminants present in the lattice, and is known as the Horsting voiding, which is a similar process to the Kirkendall voiding. | 0 | Metallurgy |
Cooling curves are important in controlling the quality of a casting. The most important part of the cooling curve is the cooling rate which affects the microstructure and properties. Generally speaking, an area of the casting which is cooled quickly will have a fine grain structure and an area which cools slowly will have a coarse grain structure. Below is an example cooling curve of a pure metal or eutectic alloy, with defining terminology.
Note that before the thermal arrest the material is a liquid and after it the material is a solid; during the thermal arrest the material is converting from a liquid to a solid. Also, note that the greater the superheat the more time there is for the liquid material to flow into intricate details.
The above cooling curve depicts a basic situation with a pure metal, however, most castings are of alloys, which have a cooling curve shaped as shown below.
Note that there is no longer a thermal arrest, instead there is a freezing range. The freezing range corresponds directly to the liquidus and solidus found on the phase diagram for the specific alloy. | 0 | Metallurgy |
Strong evidence of metallurgical activities has been revealed in levels 9 to 6, dating to the Ubaid period, and especially in level 7 (4166 +/- 170 cal BC). Hearths or natural draft furnaces, slag, ore, and pigment had been recovered throughout the site. This was in the context of architectural complexes typical of southern Mesopotamian architecture.
Unusually, the metallurgical activities at the site appear to have been limited to the melting and casting of copper objects. Arsenical copper objects were clearly manufactured on site, yet the technological aspects of this productions remain unclear. This is because the primary smelting of ore seems to have been undertaken elsewhere, perhaps already at the mining sites. So questions remain as to whether or not arsenic was already present in the ores, or added later.
In contrast, the related Norşuntepe site provides a better context of production, and demonstrates that some form of arsenic alloying was indeed taking place by the 4th millennium BC. Since the slag identified at Norşuntepe contains no arsenic, this means that arsenic was added separately. | 0 | Metallurgy |
The Goldsmiths' Professorship of Materials Science is a professorship in the University of Cambridge, associated with the Department of Materials Science and Metallurgy.
The professorship was established by grace of 20 November 1931 as the Goldsmiths Professorship of Metallurgy to replace the Goldsmiths Readership in Metallurgy. A further gift of £12,500 was received from the Goldsmiths Company in 1933. It was retitled the Goldsmiths Professorship of Materials Science by grace 4 of 19 June 1991. | 0 | Metallurgy |
Phytostabilisation is a form of phytoremediation that uses hyperaccumulator plants for long-term stabilisation and containment of tailings, by sequestering pollutants in soil near the roots. The plants presence can reduce wind erosion, or the plants roots can prevent water erosion, immobilise metals by adsorption or accumulation, and provide a zone around the roots where the metals can precipitate and stabilise. Pollutants become less bioavailable and livestock, wildlife, and human exposure is reduced. This approach can be especially useful in dry environments, which are subject to wind and water dispersion. | 0 | Metallurgy |
The importance of these untranslated regions of mRNA is just beginning to be understood. Various medical studies are being conducted that have found connections between mutations in untranslated regions and increased risk for developing a particular disease, such as cancer. For example, associations between polymorphisms in the HLA-G 3′UTR region and development of colorectal cancer have been discovered. Single Nucleotide Polymorphisms in the 3 UTR of another gene have also been associated with susceptibility to preterm birth. Mutations in the 3 UTR of the APP gene are related to development of cerebral amyloid angiopathy. | 1 | Gene expression + Signal Transduction |
The cAMP signal transduction contains five main characters: stimulative hormone receptor (Rs) or inhibitory hormone receptor (Ri); stimulative regulative G-protein (Gs) or inhibitory regulative G-protein (Gi); adenylyl cyclase; protein kinase A (PKA); and cAMP phosphodiesterase.
Stimulative hormone receptor (Rs) is a receptor that can bind with stimulative signal molecules, while inhibitory hormone receptor (Ri) is a receptor that can bind with inhibitory signal molecules.
Stimulative regulative G-protein is a G-protein linked to stimulative hormone receptor (Rs), and its α subunit upon activation could stimulate the activity of an enzyme or other intracellular metabolism. On the contrary, inhibitory regulative G-protein is linked to an inhibitory hormone receptor, and its α subunit upon activation could inhibit the activity of an enzyme or other intracellular metabolism.
Adenylyl cyclase is a 12-transmembrane glycoprotein that catalyzes the conversion of ATP to cAMP with the help of cofactor Mg or Mn. The cAMP produced is a second messenger in cellular metabolism and is an allosteric activator of protein kinase A.
Protein kinase A is an important enzyme in cell metabolism due to its ability to regulate cell metabolism by phosphorylating specific committed enzymes in the metabolic pathway. It can also regulate specific gene expression, cellular secretion, and membrane permeability. The protein enzyme contains two catalytic subunits and two regulatory subunits. When there is no cAMP，the complex is inactive. When cAMP binds to the regulatory subunits, their conformation is altered, causing the dissociation of the regulatory subunits, which activates protein kinase A and allows further biological effects.
These signals then can be terminated by cAMP phosphodiesterase, which is an enzyme that degrades cAMP to 5'-AMP and inactivates protein kinase A. | 1 | Gene expression + Signal Transduction |
Sono-Seq (Sonication of Cross-linked Chromatin Sequencing) is a method in molecular biology used for determining the sequences of those DNA regions in the genome near regions of open chromatin of expressed genes. It is also known as "Input" in the Chip-Seq protocol, since it follows the same steps except it doesn't require immunoprecipitation. | 1 | Gene expression + Signal Transduction |
Wagner's gene network model is a computational model of artificial gene networks, which explicitly modeled the developmental and evolutionary process of genetic regulatory networks. A population with multiple organisms can be created and evolved from generation to generation. It was first developed by Andreas Wagner in 1996 and has been investigated by other groups to study the evolution of gene networks, gene expression, robustness, plasticity and epistasis. | 1 | Gene expression + Signal Transduction |
In the early years of serious research into the locations of stations on the Antonine Itineraries, the location of Ariconium was in doubt, and William Camden (1551–1623) suggested Magnis, the site of modern Kenchester, some northwest of modern Hereford. Later analysis of the Antonine Itineraries, notably by John Horsley (1685–1732), refined previous estimates and ultimately placed Ariconium at Bury Hill, Weston under Penyard, west-northwest of Glevum (at modern Gloucester), and northeast of Blestium (at modern Monmouth). With confidence that the overgrown ruins near Weston under Penyard were actually the site of Ariconium, local people began clearing away the brush, revealing the enormous magnitude of the cinder piles, and further revealing the walls of buildings. Stories emerged of significant Roman-era relics, and there were unverified stories that existing relics having no provenance had actually been found in Ariconium.
Such capable modern research as has been done so far supports the characterisation of a large iron working site with massive refuse piles covering approximately , pottery remnants, and numerous artefacts. Finds have included pre-Roman British coins, including one minted by Cunobelin, and coins from the Roman arrival until 360, after which there are no coins found. | 0 | Metallurgy |
Mechanical screening, often just called screening, is the practice of taking granulated or crushed ore material and separating it into multiple grades by particle size.
This practice occurs in a variety of industries such as mining and mineral processing, agriculture, pharmaceutical, food, plastics, and recycling.
A method of separating solid particles according to size alone is called screening. | 0 | Metallurgy |
Under anoxic conditions, the mechanism for corrosion requires a substitute for oxygen as the oxidizing agent in the redox reaction. For abiotic anaerobic corrosion, that substitute is the hydrogen ion produced in the dissociation of water and the proceeding reduction of the hydrogen ions into diatomic hydrogen gas. The anodic half-reaction involves the oxidation of a metal in aqueous solution into a metal hydroxide. A common reaction that represents this process is the transformation of solid iron in steel into ferrous hydroxide as visualized in the following overall redox reaction.
The ferrous hydroxide may be oxidized further by additional hydrogen ions in water to form the mineral magnetite (FeO) in the process called the Schikorr reaction.
In general, the anaerobic corrosion of metals, such as iron and copper, occur at very slow rates. However, when in chloride-containing aqueous environments, the rate increases because of the introduction of new mechanisms with the addition of a chloride anions. | 0 | Metallurgy |
Copper is the eighth most abundant metal in the Earth's crust, is available all over the world, and is one of the few that can appear in a pure state. It is not complicated to work with, and a bare hammering can be enough to transform a nugget into a bead. The eye-catching look of native copper makes it easy to recognize, and even flashier if converted into jewelry, a possible motivation for humankind to start metallurgy with it. An evolutive technological process has been described, although there are authors like Javinovic, who think that it is not necessary to pass through the first stages to reach the last one. | 0 | Metallurgy |
β-Fe and the A critical temperature are important in induction heating of steel, such as for surface-hardening heat treatments. Steel is typically austenitized at 900–1000 °C before it is quenched and tempered. The high-frequency alternating magnetic field of induction heating heats the steel by two mechanisms below the Curie temperature: resistance or Joule heating and ferromagnetic hysteresis losses. Above the A boundary, the hysteresis mechanism disappears and the required amount of energy per degree of temperature increase is thus substantially larger than below A. Load-matching circuits may be needed to vary the impedance in the induction power source to compensate for the change. | 0 | Metallurgy |
The greatest danger of tailings ponds is dam failure, with the most publicized failure in the U.S. being the failure of a coal slurry dam in the West Virginia Buffalo Creek Flood of 1972, which killed 125 people; other collapses include the Ok Tedi environmental disaster in New Guinea, which destroyed the fishery of the Ok Tedi River. On average, worldwide, there is one big accident involving a tailings dam each year.
Other disasters caused by tailings dam failures are, the 2000 Baia Mare cyanide spill and the Ajka alumina plant accident. In 2015, the iron ore tailings dam failure at the Germano mine complex in Minas Gerais, Brazil, was the country's biggest environmental disaster. The dam breach caused the death of 19 people due to flooding of tailings slime downstream and affected some 400 km of the Doce river system with toxic effluence and out into the Atlantic Ocean. | 0 | Metallurgy |
As promoters are typically immediately adjacent to the gene in question, positions in the promoter are designated relative to the transcriptional start site, where transcription of DNA begins for a particular gene (i.e., positions upstream are negative numbers counting back from -1, for example -100 is a position 100 base pairs upstream). | 1 | Gene expression + Signal Transduction |
The invasion and settlement of the Weald by Saxons seems to have brought a complete end to the Romano-British iron industry. No evidence of iron smelting has been found after the end of Roman rule until the ninth century when a primitive bloomery was built at Millbrook on Ashdown Forest, with a small hearth for reheating the blooms nearby. The date of this site has been established by radiocarbon and archaeomagnetic methods. The technology used there was similar to a slightly earlier furnace excavated in the eastern Netherlands, indicating that knowledge of Romano-British methods had been completely lost and replaced by the Saxons' own method. Evidence of forging of iron blooms in settlements close to the South Downs does indicate that smelting may have been going on at other undiscovered sites. It was usual for settlements concentrated along the Downs to have outlying parcels of land in the Weald for summer grazing. It is likely that smelting was carried out during the summer and the iron blooms taken back to the main settlement to work on in the winter.
In all some 30 unpowered medieval bloomery sites are known in the Weald, but most of these remain undated. Accounts survive of the operation of just one, at Tudeley near Tonbridge in the mid-14th century. | 0 | Metallurgy |
Sometime in the medieval period, water power was applied to the bloomery process. It is possible that this was at the Cistercian Abbey of Clairvaux as early as 1135, but it was certainly in use in early 13th century France and Sweden. In England, the first clear documentary evidence for this is the accounts of a forge of the Bishop of Durham, near Bedburn in 1408, but that was certainly not the first such ironworks. In the Furness district of England, powered bloomeries were in use into the beginning of the 18th century, and near Garstang until about 1770.
The Catalan Forge was a variety of powered bloomery. Bloomeries with hot blast were used in upstate New York in the mid-19th century. | 0 | Metallurgy |
The relevance of observations from fission yeast mating-type regions and centromeres to mammals is not clear, as some evidence suggests that heterochromatin maintenance in mammalian cells is independent of the components of the RNAi pathway. It is known, however, that plants and animals have analogous mechanism for small RNA-guided heterochromatin formation, and it is believed that the mechanisms described above for S. pombe are highly conserved and play some role in heterochromatin formation in mammals as well. In higher eukaryotes, RNAi-dependent heterochromatic silencing appears to play a larger role in germline cells than in primary cells or cell lines, and is only one of the many different forms of gene silencing used throughout the genome, making it more difficult to study.
The role of RNAi in transcriptional gene silencing in plants has been characterized fairly well, and functions primarily through DNA methylation via the RdDM pathway. In this process, which is distinct from the process described above, argonaut-bound siRNA recognizes nascent RNA transcripts or the target DNA to guide the methylation and silencing of the target genomic region. | 1 | Gene expression + Signal Transduction |
Austempering is a hardening process that is used on iron-based metals to promote better mechanical properties. The metal is heated into the austenite region of the iron-cementite phase diagram and then quenched in a salt bath or other heat extraction medium that is between temperatures of . The metal is annealed in this temperature range until the austenite turns to bainite or ausferrite (bainitic ferrite + high-carbon austenite).
By changing the temperature for austenitization, the austempering process can yield different and desired microstructures. A higher austenitization temperature can produce a higher carbon content in austenite, whereas a lower temperature produces a more uniform distribution of austempered structure. The carbon content in austenite as a function of austempering time has been established. | 0 | Metallurgy |
Polymers come in a wide variety of compositions, and this diversity of chemistry results in wide-ranging embrittlement mechanisms. The most common sources of polymer embrittlement include oxygen in the air, water in liquid or vapor form, ultraviolet radiation from the sun, acids, and organic solvents.
One of the ways these sources alter the mechanical properties of polymers is through chain scission and chain cross-linking. Chain scission occurs when atomic bonds are broken in the main chain, so environments with elements such as solar radiation lead to this form of embrittlement. Chain scission reduces the length of the polymer chains in a material, resulting in a reduction of strength. Chain cross-linking has the opposite effect. An increase in the number of cross-links (due to an oxidative environment for example), results in stronger, less ductile material.
The thermal oxidation of polyethylene provides a quality example of chain scission embrittlement. The random chain scission induced a change from ductile to brittle behavior once the average molar mass of the chains dropped below a critical value. For the polyethylene system, embrittlement occurred when the weight average molar mass fell below 90 kg/mol. The reason for this change was hypothesized to be a reduction of entanglement and an increase in crystallinity. The ductility of polymers is typically a result of their amorphous structure, so an increase in crystallinity makes the polymer more brittle. In the case of polyethylene terephthalate, hydrolysis produces chain scission embrittlement. It has been demonstrated that the degradation of the mechanical properties correlates with the reduction of the mobile amorphous fraction (MAF), and that the ductile-to-brittle transition occurs when the minimum MAF is reached. This supports a micromechanical interpretation of the embrittlement mechanism rather than a molecular interpretation.
The embrittlement of silicone rubber is due to an increase in the amount of chain cross-linking. When silicone rubber is exposed to air at temperatures above oxidative cross-linking reactions occur at methyl side groups along the main chain. These cross-links make the rubber significantly less ductile.
Solvent stress cracking is a significant polymer embrittlement mechanism. It occurs when liquids or gasses are absorbed into the polymer, ultimately swelling the system. The polymer swelling results in less shear flow and an increase in crazing susceptibility. Solvent stress cracking from organic solvents typically results in static fatigue because of the low mobility of fluids. Solvent stress cracking from gasses is more likely to result in greater crazing susceptibility.
Polycarbonate provides a good example of solvent stress cracking. Numerous solvents have been shown to embrittle polycarbonate (i.e. benzene, toluene, acetone) through a similar mechanism. The solvent diffuses into the bulk, swells the polymer, induces crystallization, and ultimately produces interfaces between ordered and disordered regions. These interfaces produce voids and stress fields that can be propagated throughout the material at stresses much lower than the typical tensile strength of the polymer. | 0 | Metallurgy |
Four key assumptions in Scheil analysis enable determination of phases present in a cast part. These assumptions are:
# No diffusion occurs in solid phases once they are formed ()
# Infinitely fast diffusion occurs in the liquid at all temperatures by virtue of a high diffusion coefficient, thermal convection, Marangoni convection, etc. ()
# Equilibrium exists at the solid-liquid interface, and so compositions from the phase diagram are valid
# Solidus and liquidus are straight segments
The fourth condition (straight solidus/liquidus segments) may be relaxed when numerical techniques are used, such as those used in CALPHAD software packages, though these calculations rely on calculated equilibrium phase diagrams. Calculated diagrams may include odd artifacts (i.e. retrograde solubility) that influence Scheil calculations. | 0 | Metallurgy |
Melted fusible alloys can be used as coolants as they are stable under heating and can give much higher thermal conductivity than most other coolants; particularly with alloys made with a high thermal conductivity metal such as indium or sodium. Metals with low neutron cross-section are used for cooling nuclear reactors.
Such alloys are used for making the fusible plugs inserted in the furnace crowns of steam boilers, as a safeguard in the event of the water level being allowed to fall too low. When this happens the plug, being no longer covered with water, is heated to such a temperature that it melts and allows the contents of the boiler to escape into the furnace. In automatic fire sprinklers the orifices of each sprinkler is closed with a plug that is held in place by fusible metal, which melts and liberates the water when, owing to an outbreak of fire in the room, the temperature rises above a predetermined limit.
Bismuth on solidification expands by about 3.3% by volume. Alloys with at least half of bismuth display this property too. This can be used for mounting of small parts, e.g. for machining, as they will be tightly held. | 0 | Metallurgy |
Viruses (i.e., measles, mumps, or parainfluenza), especially viruses that have an RNA genome, have been shown to have evolved to utilize RNA modifications in many ways when taking over the host cell. Viruses are known to utilize the RNA modifications in different parts of their infection cycle from immune evasion to protein translation enhancement. RNA editing is used for stability and generation of protein variants. Viral RNAs are transcribed by a virus-encoded RNA-dependent RNA polymerase, which is prone to pausing and "stuttering" at certain nucleotide combinations. In addition, up to several hundred non-templated As are added by the polymerase at the 3 end of nascent mRNA. These As help stabilize the mRNA. Furthermore, the pausing and stuttering of the RNA polymerase allows the incorporation of one or two Gs or As upstream of the translational codon. The addition of the non-templated nucleotides shifts the reading frame, which generates a different protein.
Additionally, the RNA modifications are shown to have both positive and negative effects on the replication and translation efficiency depending on the virus. For example, Courtney et al. showed that an RNA modification called 5-methylcytosine is added to the viral mRNA in infected host cells in order to enhance the protein translation of HIV-1 virus. The inhibition of the mC modification on viral mRNA results in significant reduction in viral protein translation, but interestingly it has no effect on the expression of viral mRNAs in the cell. On the other hand, Lichinchi et al. showed that the N6-methyladenosine modification on ZIKV mRNA inhibits the viral replication. | 1 | Gene expression + Signal Transduction |
Phosphatases act in opposition to kinases/phosphorylases, which add phosphate groups to proteins. The addition of a phosphate group may activate or de-activate an enzyme (e.g., kinase signalling pathways) or enable a protein-protein interaction to occur (e.g., SH2 domains ); therefore phosphatases are integral to many signal transduction pathways. Phosphate addition and removal do not necessarily correspond to enzyme activation or inhibition, and that several enzymes have separate phosphorylation sites for activating or inhibiting functional regulation. CDK, for example, can be either activated or deactivated depending on the specific amino acid residue being phosphorylated. Phosphates are important in signal transduction because they regulate the proteins to which they are attached. To reverse the regulatory effect, the phosphate is removed. This occurs on its own by hydrolysis, or is mediated by protein phosphatases.
Protein phosphorylation plays a crucial role in biological functions and controls nearly every cellular process, including metabolism, gene transcription and translation, cell-cycle progression, cytoskeletal rearrangement, protein-protein interactions, protein stability, cell movement, and apoptosis. These processes depend on the highly regulated and opposing actions of PKs and PPs, through changes in the phosphorylation of key proteins. Histone phosphorylation, along with methylation, ubiquitination, sumoylation and acetylation, also regulates access to DNA through chromatin reorganisation.
One of the major switches for neuronal activity is the activation of PKs and PPs by elevated intracellular calcium. The degree of activation of the various isoforms of PKs and PPs is controlled by their individual sensitivities to calcium. Furthermore, a wide range of specific inhibitors and targeting partners such as scaffolding, anchoring, and adaptor proteins also contribute to the control of PKs and PPs and recruit them into signalling complexes in neuronal cells. Such signalling complexes typically act to bring PKs and PPs in close proximity with target substrates and signalling molecules as well as enhance their selectivity by restricting accessibility to these substrate proteins. Phosphorylation events, therefore, are controlled not only by the balanced activity of PKs and PPs but also by their restricted localisation. Regulatory subunits and domains serve to restrict specific proteins to particular subcellular compartments and to modulate protein specificity. These regulators are essential for maintaining the coordinated action of signalling cascades, which in neuronal cells include short-term (synaptic) and long-term (nuclear) signalling. These functions are, in part, controlled by allosteric modification by secondary messengers and reversible protein phosphorylation.
It is thought that around 30% of known PPs are present in all tissues, with the rest showing some level of tissue restriction. While protein phosphorylation is a cell-wide regulatory mechanism, recent quantitative proteomics studies have shown that phosphorylation preferentially targets nuclear proteins. Many PPs that regulate nuclear events, are often enriched or exclusively present in the nucleus. In neuronal cells, PPs are present in multiple cellular compartments and play a critical role at both pre- and post-synapses, in the cytoplasm and in the nucleus where they regulate gene expression.
Phosphoprotein phosphatase is activated by the hormone insulin, which indicates that there is a high concentration of glucose in the blood. The enzyme then acts to dephosphorylate other enzymes, such as phosphorylase kinase, glycogen phosphorylase, and glycogen synthase. This leads to phosphorylase kinase and glycogen phosphorylase's becoming inactive, while glycogen synthase is activated. As a result, glycogen synthesis is increased and glycogenolysis is decreased, and the net effect is for energy to enter and be stored inside the cell. | 1 | Gene expression + Signal Transduction |
Producing sponge iron and then working it was the earliest method used to obtain iron in the Middle East, Egypt, and Europe, where it remained in use until at least the 16th century.
The advantage of the bloomery technique is that iron can be obtained at a lower furnace temperature, only about 1,100 °C or so. The disadvantage, relative to a blast furnace, is that only small quantities can be made at a time. | 0 | Metallurgy |
The alkali–silica reaction (ASR) is a deleterious chemical reaction between the alkali ( and ), dissolved in concrete pore water as NaOH and KOH, with reactive amorphous (non-crystalline) siliceous aggregates in the presence of moisture. The simplest way to write the reaction in a stylized manner is the following (other representations also exist):
: (young N-S-H gel)
This reaction produces a gel-like substance of sodium silicate ( • n ), also noted • n , or N-S-H (sodium silicate hydrate). This hygroscopic gel swells inside the affected reactive aggregates which expand and crack. In its turn, it causes concrete expansion. If concrete is heavily reinforced, it can first cause some prestressing effect before cracking and damaging the structure. ASR affects the aggregates and is recognizable by cracked aggregates. It does not directly affect the hardened cement paste (HCP). | 0 | Metallurgy |
P300/CBP-associated factor (PCAF), also known as K(lysine) acetyltransferase 2B (KAT2B), is a human gene and transcriptional coactivator associated with p53. | 1 | Gene expression + Signal Transduction |
Meteorin-like/Meteorin-Beta (Metrnl)/IL-41, also known as subfatin and cometin, is a small (~27kDa) secreted cytokine, protein encoded by a gene called meteorin-like (METRNL). METRNL is highly expressed in mucosal tissues, skin and activated macrophages.
Metrnl has also been described to be a hormone
A screen of human skin-associated diseases showed significant over-expression of METRNL in psoriasis, prurigo nodularis, actinic keratosis and atopic dermatitis. METRNL is also up-regulated in synovial membranes of human rheumatoid arthritis.
Adipocyte Metrnl antagonizes obesity-induced insulin resistance by improving adipose function, including adipocyte differentiation, metabolism activation, and inflammation inhibition Lower serum levels of Metrnl might be a risk factor for developing coronary artery disease and type 2 diabetes mellitus | 1 | Gene expression + Signal Transduction |
A cover meter is an instrument to locate rebars and measure the exact concrete cover. Rebar detectors are less sophisticated devices that can only locate metallic objects below the surface. Due to the cost-effective design, the pulse-induction method is one of the most commonly used solutions. | 0 | Metallurgy |
A receptor modulator, or receptor ligand, is a general term for a substance, endogenous or exogenous, that binds to and regulates the activity of chemical receptors. They are ligands that can act on different parts of receptors and regulate activity in a positive, negative, or neutral direction with varying degrees of efficacy. Categories of these modulators include receptor agonists and receptor antagonists, as well as receptor partial agonists, inverse agonists, orthosteric modulators, and allosteric modulators, Examples of receptor modulators in modern medicine include CFTR modulators, selective androgen receptor modulators (SARMs), and muscarinic ACh receptor modulators. | 1 | Gene expression + Signal Transduction |
The HiFIT hammer operates with a hardened pin with a ball resting on the workpiece with a diameter D of 3 mm.
This pin is hammered with an adjustable intensity at around 180–300 Hz at the weld toe. Local mechanical deformations occur in the form of a treatment track. The weld toe is deformed plastically. The induced compressive residual stress prevents the track cracking and the crack propagation on the surface. | 0 | Metallurgy |
As with conventional manufactured drugs, the main challenge in developing successful offshoots of the RNAi-based drugs is the precise delivery of the RNAi triggers to where they are needed in the body. The reason that the ocular macular degeneration antidote was successful sooner than the antidote with other diseases is that the eyeball is almost a closed system, and the serum can be injected with a needle exactly where it needs to be. The future successful drugs will be the ones who are able to land where needed, probably with the help of nanobots. Below is a rendition of a table that shows the existing means of delivery of the RNAi triggers. | 1 | Gene expression + Signal Transduction |
A quench press is a machine that uses concentrated forces to hold an object as it is quenched. These types of quench facilities are used to quench large gears and other circular parts so that they remain circular. They are also used to quench saw blades and other flat or plate-shaped objects so that they remain flat.
Quench presses are able to quench the part while it is being held because of the unique structure of the clamps holding the part. Clamps are slotted so that oil or water can flow through each slot and cool the part and the ribs of the clamps can hold the part in place. | 0 | Metallurgy |
There have been a variety of long-overlap-based assembly methods developed in recent years. One of the most commonly used methods, the Gibson assembly method, was developed in 2009, and provides a one-pot DNA assembly method that does not require the use of restriction enzymes or integrases. Other similar overlap-based assembly methods include Circular Polymerase Extension Cloning (CPEC), Sequence and Ligase Independent Cloning (SLIC) and Seamless Ligation Cloning Extract (SLiCE). Despite the presence of many overlap assembly methods, the Gibson assembly method is still the most popular. Besides the methods listed above, other researchers have built on the concepts used in Gibson assembly and other assembly methods to develop new assembly strategies like the Modular Overlap-Directed Assembly with Linkers (MODAL) strategy, or the Biopart Assembly Standard for Idempotent Cloning (BASIC) method. | 1 | Gene expression + Signal Transduction |
Gold occurs principally as a native metal, i.e., gold itself. Sometimes it is alloyed to a greater or lesser extent with silver, which is called electrum. Native gold can occur as sizeable nuggets, as fine grains or flakes in alluvial deposits, or as grains or microscopic particles (known as colour) embedded in rock minerals. Other forms of gold are the minerals calaverite (AuTe), aurostibnite (AuSb), and maldonite (AuBi). These latter three, although rarer that native gold, can be slow to react with cyanide and thus difficult to process. Still other gold-containing ores include various tellurides (sylvanite, nagyagite, petzite, and krennerite).
Certain contaminants in ores can interfere with the extractability of gold by cyanide. These interfering agents are called "preg-robbing ores". For example, gold can bind tightly to carbon, resisting normal cyanide extraction. Gold cyanides bind also to some clays. | 0 | Metallurgy |
Risers, also known as feeders, are the most common way of providing directional solidification. It supplies liquid metal to the solidifying casting to compensate for solidification shrinkage. For a riser to work properly the riser must solidify after the casting, otherwise it cannot supply liquid metal to shrinkage within the casting. Risers add cost to the casting because it lowers the yield of each casting; i.e. more metal is lost as scrap for each casting. Another way to promote directional solidification is by adding chills to the mold. A chill is any material which will conduct heat away from the casting more rapidly than the material used for molding.
Risers are classified by three criteria. The first is if the riser is open to the atmosphere, if it is then it is called an open riser, otherwise it is known as a blind type. The second criterion is where the riser is located; if it is located on the casting then it is known as a top riser and if it is located next to the casting it is known as a side riser. Finally, if the riser is located on the gating system so that it fills after the molding cavity, it is known as a live riser or hot riser, but if the riser fills with materials that have already flowed through the molding cavity it is known as a dead riser or cold riser.
Riser aids are items used to assist risers in creating directional solidification or reducing the number of risers required. One of these items are chills which accelerate cooling in a certain part of the mold. There are two types: external and internal chills. External chills are masses of high-heat-capacity and high-thermal-conductivity material that are placed on an edge of the molding cavity. Internal chills are pieces of the same metal that is being poured, which are placed inside the mold cavity and become part of the casting. Insulating sleeves and toppings may also be installed around the riser cavity to slow the solidification of the riser. Heater coils may also be installed around or above the riser cavity to slow solidification. | 0 | Metallurgy |
All seven STAT proteins share a common structural motif consisting of an N-terminal domain followed by a coiled-coil, DNA-binding domain, linker, Src homology 2 (SH2), and a C-terminal transactivation domain. Much research has focused on elucidating the roles each of these domains play in regulating different STAT isoforms. Both the N-terminal and SH2 domains mediate homo or heterodimer formation, while the coiled-coil domain functions partially as a nuclear localization signal (NLS). Transcriptional activity and DNA association are determined by the transactivation and DNA-binding domains, respectively. | 1 | Gene expression + Signal Transduction |
It has been proposed that mutations in gatekeeper genes could, to an extent, offer a sort of selective advantage to the individual in which the change occurs. This is because cells with these mutations are able to replicate at a faster rate than nearby cells. This is known as "increased somatic fitness". Caretaker genes, on the other hand, confer selective disadvantage because the result is inherently decreased cellular success. However, increased somatic fitness could also arise from a mutation in a caretaker gene if mutations in tumor suppressor genes increase the net reproductive rate of the cell.
Although mutations in gatekeeper genes may lead to the same result as those of caretaker genes, namely cancer, the transcripts that gatekeeper genes encode are significantly different from those encoded by caretaker genes.
In many cases, gatekeeper genes encode a system of checks and balances that monitor cell division and death. In cases of tissue damage, for example, gatekeeper genes would ensure that balance of cell growth over cellular death remains in check. In the presence of competent gatekeeper genes, mutations of other genes would not lead to on-going growth imbalances.
Whether or not mutations in these genes confer beneficial or deleterious effects to the animal depends partially on the environmental context in which these changes occur, a context encoded by the landscaper genes. For example, tissues of the skin and colon reside in compartments of cells that rarely mix with one another. These tissues are replenished by stem cells. Mutations that occur within these cell lineages remain confined to the compartment in which they reside, increasing the future risk of cancer. This is also protective, however, because the cancer will remain confined to that specific area, rather than invading the rest of the body, a phenomenon known as metastasis.
In areas of the body compartmentalized into small subsets of cells, mutations that lead to cancer most often begin with caretaker genes. On the other hand, cancer progression in non-compartmentalized or large cell populations may be a result of initial mutations in gatekeepers.
These delineations offer a suggestion why different types of tissue within the body progress to cancer by differing mechanisms. | 1 | Gene expression + Signal Transduction |
An amorphous metal (also known as metallic glass, glassy metal, or shiny metal) is a solid metallic material, usually an alloy, with disordered atomic-scale structure. Most metals are crystalline in their solid state, which means they have a highly ordered arrangement of atoms. Amorphous metals are non-crystalline, and have a glass-like structure. But unlike common glasses, such as window glass, which are typically electrical insulators, amorphous metals have good electrical conductivity and can show metallic luster.
There are several ways in which amorphous metals can be produced, including extremely rapid cooling, physical vapor deposition, solid-state reaction, ion irradiation, and mechanical alloying. Previously, small batches of amorphous metals had been produced through a variety of quick-cooling methods, such as amorphous metal ribbons which had been produced by sputtering molten metal onto a spinning metal disk (melt spinning). The rapid cooling (in the order of millions of degrees Celsius a second) is too fast for crystals to form and the material is "locked" in a glassy state. Currently, a number of alloys with critical cooling rates low enough to allow formation of amorphous structure in thick layers (over ) have been produced; these are known as bulk metallic glasses. More recently, batches of amorphous steel with three times the strength of conventional steel alloys have been produced. New techniques as 3D printing, also characterised by their high cooling rates, are an active research topic for manufacturing bulk metallic glasses. | 0 | Metallurgy |
Most presynaptic terminals release small numbers of neurotransmitter containing vesicles even when action potentials are not present. This is stochastic and the probability of release (Pr) can be modified by numerous factors including the presence and speed of an action potential. These vesicles are released at synaptic active zones, areas of the axon terminal that have all of the machinery and conditions necessary to specialize in vesicle fusion with the plasma membrane. Until relatively recently, the prevailing hypothesis was that only one vesicle at a time is released from these active zones. However, research over the past several decades has added support for an additional mechanism of neurotransmitter vesicle release. | 1 | Gene expression + Signal Transduction |
Suppressor of cytokine signaling 1 is a protein that in humans is encoded by the SOCS1 gene. SOCS1 orthologs have been identified in several mammals for which complete genome data are available. | 1 | Gene expression + Signal Transduction |
By 1900 the US was the largest producer and also the lowest cost producer, and demand for steel seemed inexhaustible. Output had tripled since 1890, but customers, not producers, mostly benefitted. Productivity-enhancing technology encouraged faster and faster rates of investment in new plants. However, during recessions, demand fell sharply taking down output, prices, and profits. Charles M. Schwab of Carnegie Steel proposed a solution: consolidation. Financier J. P. Morgan arranged the buyout of Carnegie and most other major firms, and put Elbert Gary in charge. The massive Gary Works steel mill on Lake Michigan was for many years the largest steel producing facility in the world.
US Steel combined finishing firms (American Tin Plate (controlled by William Henry "Judge" Moore), American Steel and Wire, and National Tube) with two major integrated companies, Carnegie Steel and Federal Steel. It was capitalized at $1.466 billion, and included 213 manufacturing mills, one thousand miles of railroad, and 41 mines. In 1901, it accounted for 66% of Americas steel output, and almost 30% of the worlds. During World War I, its annual production exceeded the combined output of all German and Austrian firms.
The Steel Strike of 1919 disrupted the entire industry for months, but the union lost and its membership sharply declined. Rapid growth of cities made the 1920s boom years. President Harding and social reformers forced it to end the 12-hour day in 1923.
Earnings were recorded at $2.650 billion for 2016. | 0 | Metallurgy |
Silent antagonists are competitive receptor antagonists that have zero intrinsic activity for activating a receptor. They are true antagonists, so to speak. The term was created to distinguish fully inactive antagonists from weak partial agonists or inverse agonists. | 1 | Gene expression + Signal Transduction |
The Jameson Cell reportedly has the following advantages:
* relatively low energy use – the only energy that is required to operate the Cell is to pump the slurry through the slurry lens. This means that it requires significantly less electricity than conventional mechanical or column flotation cells. In addition, the better particle–bubble contact means that fewer Cells are required for the equivalent duty of mechanical cells, giving an even bigger power saving.
* high recovery of fines – The Cell is able to achieve final product specification from previously discarded coal fines at very high recoveries (95–98%) in a single pass. It has also been shown to be effective in recovering fine particles in base metals, potash and phosphate applications.
* effective froth washing – The Cell uses froth washing as standard to control concentrate grade. A conventional flotation cell has problems with recovering fine particles at high grades due to the entrainment of gangue minerals in the froth. The high throughput of the Jameson Cell means that the froth is produced in a small surface area so it is economic to apply froth washing to all cells
* easily scaled up – the hydrodynamic conditions for particle collection inside the downcomer and separation in the tank are identical between the laboratory, pilot plant and industrial-scale Jameson Cell, meaning that there is direct scale-up. This makes predicting plant performance for small-scale tests straightforward. In contrast, factors have to be used to scale-up the design of mechanical and column flotation cells.
* relatively small footprint – the high intensity of bubble-particle contact means that very low residence times are required in the Cell (residence time in the downcomer is 5–10 seconds and the separation tank volume is small compared with alternative technologies). This means that the total volume of the Cell is lower than the alternatives.
* fast response to process changes – process variables such as air flow rate, froth depth and wash water are all automated making optimisation straightforward. The small tank volumes means very short residence times in the tank (typically 1–3 minutes) so changes made, whether they are deliberate or from normal plant fluctuations, are observed almost instantly.
* rapid start-up and shutdown – the small volume of the tank means that the Cell can be filled and drained quickly so with plant upsets the Cell can reach steady state very quickly.
* low maintenance costs – the Cell has no moving parts and is designed to provide easy access to serviceable parts. The slurry lens orifice has a service life exceeding 5 years under normal operating conditions and the service life of the other wet-end wear parts is reported to be over 10 years under normal operating conditions.
* low capital cost – the small footprint of the Cell reduces the amount of steel required in its construction and, coupled with the simplicity of its design, has lower installation costs when compared with conventional or column flotation cells.
* low operating costs – the lack of moving parts with a consequent lower power consumption, long wear life and easy access results in low operating costs.
* short payback periods – Cell users typically report short payback periods for their investments in the technology. For example, the 2007 installation of a 5.4 m diameter Jameson Cell with 18 downcomers to treat preflotation concentrate recovered up to 90% of the zinc previously lost to the tailings disposal facility and had a payback of approximately one year at the zinc prices of the day. Peko Mines reported a payback period of two months for its Cell installation. The complete replacement of 32 mechanical cells with eight Jameson Cells at the Goonyella coal mine had a payback of 17 months. More recently, the installation of a Cell ahead of each of two cleaner trains at the Telfer Mine had a payback of between two and seven months. | 0 | Metallurgy |
German scientists at Saarland University have produced a prototype machine that transfers heat using a nickel-titanium ("nitinol") alloy wire wrapped around a rotating cylinder. As the cylinder rotates, heat is absorbed on one side and released on the other, as the wire changes from its "superelastic" state to its unloaded state. According to a 2019 article released by Saarland University, the efficiency by which the heat is transferred appears to be higher than that of a typical heat pump or air conditioner.
Almost all air conditioners and heat pumps in use today employ vapor-compression of refrigerants. Over time, some of the refrigerants used in these systems leak into the atmosphere and contribute to global warming. If the new technology, which uses no refrigerants, proves economical and practical, it might offer a significant breakthrough in the effort to reduce climate change. | 0 | Metallurgy |
Receptor uncoupling/phosphorylation is the most rapid form of desensitization that happens within a cell, as its effects are seen within seconds to minutes of agonist application. The ß adrenergic receptor was the first to have its desensitization studied and characterized. The mechanism of desensitization involves the action of a specific GRK, denoted ßARK, and also ß-arrestins. The ß-arrestins show high affinity for receptors that are both phosphorylated and activated, but are still able to bind non-phosphorylated receptors with a lower affinity. Additionally, ß-arrestins are better at inactivating ßARK-phosphorylated receptors rather than protein kinase A-phosphorylated receptors, which suggests that the arrestins preferentially mediate homologous desensitization.
The mechanism of homologous desensitization for the β receptor is as follows:
# Agonist binds and activates the receptor, which changes to an active conformational state.
# Beta adrenergic receptor kinase (βARK), a cytoplasmic kinase is activated and phosphorylates the C-terminus of the β receptor.
# This phosphorylation increases the affinity of β-arrestin for the receptor, resulting in uncoupling of the α subunit of the heterotrimeric G-protein from the receptor, producing desensitization. | 1 | Gene expression + Signal Transduction |
Liquation requires that the silver-rich copper first be melted with approximately three times its weight in lead; as silver has a greater affinity with lead, most of the silver would end up within this rather than the copper. If the copper is assayed and found to contain too little silver for liquation to be financially viable (around 0.31% is the minimum required,) it is melted and allowed to settle so that much of the silver sinks towards the bottom. The ‘tops’ are then drawn off and used to produce copper while the silver-rich ‘bottoms’ are used in the liquation process. The copper-lead alloy created can be tapped off and cast into large plano-convex ingots known as ‘liquation cakes’. As the metals cool and solidify the copper and the silver-containing lead separate as they are immiscible with each other.
The ratio of lead to copper in these cakes is an important factor for the process to work efficiently. Agricola recommended 3 parts copper to 8–12 parts lead. The copper must be assayed to accurately determine how much silver it contains; for copper rich in silver the top end of this ratio was used to make sure the maximum amount of silver possible would end up within the lead. However, there also needs to be enough copper to allow the cakes to keep their shape once most of the lead has drained away; too much copper and it would trap some of the lead within and the process would be very inefficient.
The size of these cakes remained consistent from when Agricola wrote of them in 1556 to the 19th century when the process became obsolete. They were usually thick, about in diameter and weighed from . This consistency is not without reason as the size of the cakes is very important to the smooth running of the liquation process. If the cakes are too small, the product would not be worth the time and costs spent on the process, if they are too large then the copper would begin to melt before the maximum amount of lead has drained away.
The cakes are heated in a liquation furnace, usually four or five at once, to a temperature above the melting point of lead (327°C), but below that of copper (1084 °C), so that the silver-rich lead melts and flows away. As the melting point of lead is so low a high-temperature furnace is not required and it can be fuelled with wood. It is important that this takes place in a reducing atmosphere, i.e. one with little oxygen, to avoid the lead oxidising; the cakes are therefore well covered by charcoal and little air is allowed into the furnace. It is impossible to stop some of the lead oxidising, however, and this drops down and forms spiky projections known as ‘liquation thorns’ in the channel underneath the hearth.
The older and relatively simple method of cupellation can then be used to separate the silver from the lead. If the lead is assayed and found not to contain enough silver to make the cupellation process worthwhile it is reused in liquation cakes until it has sufficient silver.
The ‘exhausted liquation cakes’ which still contain some lead and silver are ‘dried’ in a special furnace which is heated to a higher temperature under oxidising conditions. This is essentially just another stage of liquation and most of the remaining lead is expelled and oxidised to form liquation thorns, though some remains as lead metal. The copper can then be refined to remove other impurities and produce copper metal.
Waste products can be reused to produce new liquation cakes to try to minimise loss of metals, especially silver. The waste products are mostly in the form of liquation thorns from the liquation and the drying process but there are also some slags produced. | 0 | Metallurgy |
An inhibitor is usually a material added in a small quantity to a particular environment that reduces the rate of corrosion. They may be classified a number of ways but are usually 1) Oxidizing; 2) Scavenging; 3) Vapor-phase inhibitors; Sometimes they are called Volatile corrosion inhibitor 4) Adsorption inhibitors; 5) Hydrogen-evolution retarder. Another way to classify them is chemically. As there is more concern for the environment and people are more keen to use Renewable resources, there is ongoing research to modify these materials so they may be used as corrosion inhibitors. | 0 | Metallurgy |
Flux is a reducing agent designed to help reduce (return oxidized metals to their metallic state) metal oxides at the points of contact to improve the electrical connection and mechanical strength. The two principal types of flux are acid flux (sometimes called "active flux"), containing strong acids, used for metal mending and plumbing, and rosin flux (sometimes called "passive flux"), used in electronics. Rosin flux comes in a variety of "activities", corresponding roughly to the speed and effectiveness of the organic acid components of the rosin in dissolving metallic surface oxides, and consequently the corrosiveness of the flux residue.
Due to concerns over atmospheric pollution and hazardous waste disposal, the electronics industry has been gradually shifting from rosin flux to water-soluble flux, which can be removed with deionized water and detergent, instead of hydrocarbon solvents. Water-soluble fluxes are generally more conductive than traditionally used electrical / electronic fluxes and so have more potential for electrically interacting with a circuit; in general it is important to remove their traces after soldering. Some rosin type flux traces likewise should be removed, and for the same reason.
In contrast to using traditional bars or coiled wires of all-metal solder and manually applying flux to the parts being joined, much hand soldering since the mid-20th century has used flux-core solder. This is manufactured as a coiled wire of solder, with one or more continuous bodies of inorganic acid or rosin flux embedded lengthwise inside it. As the solder melts onto the joint, it frees the flux and releases that on it as well. | 0 | Metallurgy |
Chalconatronite is a carbonate mineral and rare secondary copper mineral that contains copper, sodium, carbon, oxygen, and hydrogen, its chemical formula is NaCu(CO)•3(HO). Chalconatronite is partially soluble in water, and only decomposes, although chalconatronite is soluble while cold, in dilute acids. The name comes from the minerals compounds, copper ("chalcos'" in Greek) and natron, naturally forming sodium carbonate. The mineral is thought to be formed by water carrying alkali carbonates (possibly from soil) reacting with bronze. Similar minerals include malachite, azurite, and other copper carbonates. Chalconatronite has also been found and recorded in Australia, Germany, and Colorado. | 0 | Metallurgy |
Members of the HNF1 subfamily contain a POU-homeodomain and bind to DNA as homodimers.
* HNF1α/TCF1/MODY3 (related disease: MODY 3)
* HNF1β/TCF2/MODY5 (related disease: MODY 5) | 1 | Gene expression + Signal Transduction |
In 1942, the Metallurgical Laboratory at the University of Chicago was building the worlds first nuclear reactor called Chicago Pile-1' as part of the Manhattan Project. This would have required an enormous number of graphite blocks and uranium pellets. At the time, there was a limited source of pure uranium. Frank Spedding of Iowa State University was able to produce only two short tons of pure uranium. However, a larger quantity of additional uranium metal was required for the pile to go critical.
Around that time, Westinghouse Lamp Plant was able to supply a small amount of pure uranium metal. By 1941, there was an order for the uranium metal of 10 kilograms which was considered an enormous amount. The plant ramped up the production using makeshift equipment including metal garbage cans from a local market to use in the process. The order was fulfilled within a couple of months. By early 1942, there was another order from Arthur H. Compton of the Metallurgical Laboratory for three short tons of the uranium metal for the Chicago Pile-1.
The project was done in secrecy by not revealing any connection of the work there to the ongoing research on the nuclear reaction. To avoid leaking of information about the project at the plant, it was covered with the program called Tuballoy which was the codename for uranium in programs related to the Manhattan Project, taken from the British atomic weapons effort "Tube Alloys" which had been folded into Manhattan. Due to inadequate equipment and space, the refinement process was done in an ad hoc fashion having some operations done in the basement and some on the roof on a building at the plant. To maintain the confidentiality of the program, many workers who worked on the chemical processes were not familiar with it. Most of them did not know that their work was related to the creation of an atomic weapon.
Although the material and the processes were kept secret, the workers there knew they worked as part of the World War II efforts. They were led to believe that they worked on making conventional bombs. During the height of the production in 1942, there was a war production drive at the plant under the auspices of the labor-management committee to increase its production and warned workers against sabotage. The streets at the plant were renamed to MacArthur Avenue and MacArthur Plaza to promote patriotism.
Finally, the required amount of uranium metal was delivered to Chicago by the Army with containers clearly marked "URANIUM". The Chicago Pile-1 had gone to self-sustaining reaction on December 2, 1942, with the majority of uranium metal from the plant. After that, the plant continued to play a major role in supplying the uranium metal for the Manhattan Project until October 1943 when a better and more economical process was done elsewhere. During the contract, the plant produced 69 short tons of uranium metal in total. | 0 | Metallurgy |
CORROSION es una banda de Thrash metal Paraguaya ceada en 1992 en Asunción
con partes de los integrantes de la Banda de Thrash Rawhide.Tiene como influencias a las tipicas bandas de metal como Slayer,Mettalica,Dorsal Atlantica,etc
La banda Se creo en 1992 con las cenizas de Rawhide,Lanzaron un Demo + Bonus tracks Y un LP album de studio(Report of Explotation) Despues de su ultima gira en 1995 en varios escenarios de Paraguay y Sao paulo y entre eso se disolvieron por problemas personales.
Luego en 2013 volvieron haciendo un concierto en el estadio de Sol de America con varios grupos de Thrash Muy conocidos...
En 2021 Lanzaron un Boxset de Report of Explotation.
En 1992 lanzaron un demo + Bonus tracks llamado Reinos Depredados,luego Grabaron el Famoso album de Studio como LP Report of Explotation en 1993 Grabado en brazil en el estudio de Nas Nuvens de Río de Janeiro y fue lanzado bajo el sello de Dynamo brazil.
# Reinos Depredados
# Aventon de la muerte
# Escucha tu Conciencia
# Corrosion
# Freneticos
Bonus tracks
# Reinos Depredados (estudio demo)
# Intro - Aventón de la Muerte (en vivo)
# Reinos Depredados (en vivo)
# For Whom the Bell Tolls (Metallica Cover) (live)
# Noema (live)
# Escucha a Tu Conciencia (live)
# Frenéticos (live)
# Himno a la Alegría (live)
# Huellas de Corrosión (live)
# Skeletons of Society (Slayer cover) (live)
# Reinos Depredados [Bis] (live)
# Aventón de la Muerte [Bis] (live)
# Letragia Ancestral (studio version)
Duracion:
# Zeitgeist
# Genesis of Terror
# Deforested Kingdoms
# Castle of sir jan
B Side
# Listen to your conciensce
# Noema
# Hitch-Hicking Death
# Signs Of Corrosion
# Tesay Ro
# Letergia Ancestral
# Letergia Ancestral
# Reinos depredados
# Escucha Tu Conciencia
# Deforested Kingdoms
# Signs of corrosion | 0 | Metallurgy |
Gold–aluminium intermetallic is a type of intermetallic compound of gold and aluminium which usually forms at contacts between the two metals. Gold–aluminium intermetallic have different properties from the individual metals, such as low conductivity and high melting point depending on their composition. Furthermore, Due to the difference of density between the metals and intermetallics, the growth of the intermetallic layers causes reduction in volume, and therefore creates gaps in the metal near the interface between gold and aluminium. The production of gaps lowers the strength of the metal compound, which can cause mechanical failure at the joint, fostering the problems that the intermetallics causes in metal compounds. These properties can cause problems in wire bonding in microelectronics. The main compounds formed are usually AuAl (white plague) and AuAl (purple plague), which both form at high temperatures, then AuAl and AuAl can further react with Au to form more stable compound, AuAl. | 0 | Metallurgy |
RNAa has been used to study gene function in lieu of vector-based gene overexpression. Studies have demonstrated RNAa in vivo and its potential therapeutic applications in treating cancer and non-cancerous diseases.
In June 2016, UK-based MiNA Therapeutics announced the initiation of a phase I trial of the first-ever saRNA drug MTL-CEBPA in patients with liver cancer, in an attempt to activate CEBPA gene. | 1 | Gene expression + Signal Transduction |
* SOX gene family
** Sex-Determining Region Y Protein
** SOX1, SOX2, etc.
* TCF/LEF family (T cell factor/lymphoid enhancer factor family)
** LEF1 (Lymphoid enhancer-binding factor 1)
** TCF7 (TCF-1)
** TCF7L1 (TCF-3)
** TCF7L2 (TCF-4) | 1 | Gene expression + Signal Transduction |
NANOG is a transcription factor in embryonic stem cells (ESCs) and is thought to be a key factor in maintaining pluripotency. NANOG is thought to function in concert with other factors such as POU5F1 (Oct-4) and SOX2 to establish ESC identity. These cells offer an important area of study because of their ability to maintain pluripotency. In other words, these cells have the ability to become virtually any cell of any of the three germ layers (endoderm, ectoderm, mesoderm). It is for this reason that understanding the mechanisms that maintain a cell's pluripotency is critical for researchers to understand how stem cells work, and may lead to future advances in treating degenerative diseases.
NANOG has been described to be expressed in the posterior side of the epiblast at the onset of gastrulation. There, NANOG has been implicated in inhibiting embryonic hematopoiesis by repressing the expression of the transcription factor Tal1. In this embryonic stage, NANOG represses Pou3f1, a transcription factor crucial for the anterior-posterior axis formation.
Analysis of arrested embryos demonstrated that embryos express pluripotency marker genes such as POU5F1, NANOG and Rex1. Derived human ESC lines also expressed specific pluripotency markers:
*TRA-1-60
*TRA-1-81
*SSEA4
*alkaline phosphatase
*TERT
*Rex1
These markers allowed for the differentiation in vitro and in vivo conditions into derivatives of all three germ layers.
POU5F1, TDGF1 (CRIPTO), SALL4, LECT1, and BUB1 are also related genes all responsible for self-renewal and pluripotent differentiation.
The NANOG protein has been found to be a transcriptional activator for the Rex1 promoter, playing a key role in sustaining Rex1 expression. Knockdown of NANOG in embryonic stem cells results in a reduction of Rex1 expression, while forced expression of NANOG stimulates Rex1 expression.
Besides the effects of NANOG in the embryonic stages of life, ectopic expression of NANOG in the adult stem cells can restore the proliferation and differentiation potential that is lost due to organismal aging or cellular senescence. | 1 | Gene expression + Signal Transduction |
Corepressor proteins also bind to the surface of the ligand binding domain of nuclear receptors, but through a LXXXIXXX(I/L) motif of amino acids (where L = leucine, I = isoleucine and X = any amino acid). In addition, compressors bind preferentially to the apo (ligand free) form of the nuclear receptor (or possibly antagonist bound receptor).
* CtBP 602618 (associates with class II histone deacetylases)
* LCoR (ligand-dependent corepressor)
* Nuclear receptor CO-Repressor (NCOR)
** NCOR1 ()
** NCOR2 ()/SMRT (Silencing Mediator (co-repressor) for Retinoid and Thyroid-hormone receptors) (associates with histone deacetylase-3)
* Rb (retinoblastoma protein) (associates with histone deacetylase-1 and -2)
* RCOR (REST corepressor)
** RCOR1 ()
** RCOR2 ()
** RCOR3 ()
* Sin3
** SIN3A ()
** SIN3B ()
* TIF1 (transcriptional intermediary factor 1)
** TRIM24 Tripartite motif-containing 24 ()
** TRIM28 Tripartite motif-containing 28 ()
** TRIM33 Tripartite motif-containing 33 () | 1 | Gene expression + Signal Transduction |
In genetics, a transcription terminator is a section of nucleic acid sequence that marks the end of a gene or operon in genomic DNA during transcription. This sequence mediates transcriptional termination by providing signals in the newly synthesized transcript RNA that trigger processes which release the transcript RNA from the transcriptional complex. These processes include the direct interaction of the mRNA secondary structure with the complex and/or the indirect activities of recruited termination factors. Release of the transcriptional complex frees RNA polymerase and related transcriptional machinery to begin transcription of new mRNAs. | 1 | Gene expression + Signal Transduction |
In the negative feedback loops, CK1ε periodically binds to and phosphorylates the PER proteins (PER1, PER2, and PER3), which form heterodimers with each other and interact with CRY1 and CRY2. The effects of phosphorylation are two-fold. It has been shown in Drosophila that phosphorylation of the PER proteins increase their ubiquitination, which leads to degradation. Phosphorylation of the PER proteins also leaves them unable to enter the nucleus, where they suppress transcription of clock genes. The blocking of nuclear translocation occurs via phosphorylation of PER at the nuclear localization signal, which masks the signal and prevents nuclear entry. However, this CK1ε-mediated constraint to the cytoplasm can be overcome when the PER protein complex is bound to CRY. CK1ε has been shown to phosphorylate CRY when both CK1ε and CRY are complexed with PER in vitro, but the functional significance of this remains undetermined.
CK1ε may also have a role in positive feedback; the transcription factor BMAL1 is a CK1ε substrate in vitro, and increased CK1ε activity has been shown to positively regulate transcription of genes under the influence of BMAL1-dependent circadian gene promoters. This has not yet been studied in vivo. | 1 | Gene expression + Signal Transduction |
The noncanonical Wnt pathways provide a signal transduction pathway for Wnt that does not involve β-catenin. In the noncanonical pathways, Wnt affects the actin and microtubular cytoskeleton as well as gene transcription. | 1 | Gene expression + Signal Transduction |
The first use of the term ‘transcription factory’ was used in 1993 by [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC413307/Jackson] and his colleagues who noticed that transcription occurred at discrete sites in the nucleus. This contradicted the original view that transcription occurred at an even distribution throughout the nucleus. | 1 | Gene expression + Signal Transduction |
The discovery of dephosphorylation came from a series of experiments examining the enzyme phosphorylase isolated from rabbit skeletal muscle. In 1955, Edwin Krebs and Edmond Fischer used radiolabeled ATP to determine that phosphate is added to the serine residue of phosphorylase to convert it from its b to a form via phosphorylation. Subsequently, Krebs and Fischer showed that this phosphorylation is part of a kinase cascade. Finally, after purifying the phosphorylated form of the enzyme, phosphorylase a, from rabbit liver, ion exchange chromatography was used to identify phosphoprotein phosphatase I and II.
Since the discovery of these dephosphorylating proteins, the reversible nature of phosphorylation and dephosphorylation has been associated with a broad range of functional proteins, primarily enzymatic, but also including nonenzymatic proteins. Edwin Krebs and Edmond Fischer won the 1992 Nobel Prize in Physiology or Medicine for the discovery of reversible protein phosphorylation. | 1 | Gene expression + Signal Transduction |
From 1992 to 1993, Marrow was appointed as postdoctoral research associate in the Department of Materials, University of Oxford, and a junior research fellow at Linacre College, Oxford, but moved with an Engineering and Physical Sciences Research Council (EPSRC) postdoctoral research fellowship to the School of Metallurgy and Materials, University of Birmingham. In 2001, he joined the Manchester Materials Science Centre, University of Manchester, as senior lecturer in physical metallurgy, where he became assistant director of Materials Performance Centre in 2002 and the director in 2009.
Marrow moved to the University of Oxford to become Oxford Martin School co-director of the school programme in Nuclear and Energy Materials from 2010 to 2015, Professor in Energy Materials, Department of Materials, Oxford University, and Fellow of Mansfield College, Oxford. , Marrow is the Associate Head of Department of Materials (Teaching).
Marrow is a council member of the UK Forum for Engineering Structural Integrity (FESI), UK representative for the European Energy Research Alliance Joint Programme on Nuclear Materials, member (ex-chair) of the OECD-NEA Expert Group on Innovative Structural Materials, independent advisor to the UK Office of Nuclear Regulation on materials/structural integrity, and UK representative on Graphite for BEIS to the Generation IV International Forum. Marrow is the co-director of the Nuclear Research Centre (NRC), which is a joint venture between the University of Bristol and the University of Oxford to train new nuclear scientists and engineers. | 0 | Metallurgy |
With the invention of hollow casting bronze became the most important medium of monumental sculpture, largely because of its strength and lightness, which admitted poses that would not be possible in stone. But the value of the metal in later ages has involved the destruction of nearly all such statues. The few complete figures that survive, and a somewhat more numerous series of detached heads and portrait-busts, attest the excellence of ancient work in this material. The earliest statuettes are chiselled, wrought and welded; next in time come solid castings, but larger figures were composed of hammered sections, like domestic utensils, each part worked separately in repoussé and the whole assembled with rivets (σφυρήλατα). Very little of this flimsy fabric is extant, but chance has preserved one bust entire, in the Polledrara Tomb at Vulci. This belongs to the early 6th century BC, the age of repoussé work.
The process was soon superseded in such subjects by hollow casting, but beaten reliefs, the household craft from which Greek bronze work sprang, persisted in some special and highly perfected forms, as handle-plates on certain vases, emblemata on mirror-cases, and particularly as ornaments of armour, where light weight was required. The Siris bronzes in the British Museum are shoulder-pieces from a 4th-century cuirass. Casting was done by the cire perdue process in clay moulds, but a great deal of labour was spent on finishing. The casts are very finely chased, and most large pieces contain patches, inserted to make good the flaws. Heads and limbs of statues were cast separately and adjusted to the bodies: besides the evidence of literature and of the actual bronzes, there is an illustration of a dismembered statue in the making on a painted vase in Berlin.
Pliny and other ancient writers have much to say in regard to various alloys of bronze — Corinthian, Delian, Aeginetan, Syracusan — in regard to their composition and uses and particularly to their colour effects, but their statements have not been confirmed by modern analyses and are sometimes manifestly false. Corinthian bronze is said to have been first produced by accident in the Roman burning of the city (146 BC) when streams of molten copper, gold and silver mingled. Similar tales are told by Plutarch and Pliny about the artists' control of colour: Silanion made a pale-faced Jocasta by mixing silver with his bronze, Aristonidas made Athamas blush with an alloy of iron. There is good evidence that Greek and Roman bronzes were not artificially patinated, though many were gilt or silvered. Plutarch admires the blue colour of some very ancient statues at Delphi, and wonders how it was produced; Pliny mentions a bitumen wash, but this was doubtless a protective lacquer; and a 4th-century inscription from Chios records the regulations made there for keeping a public statue clean and bright. | 0 | Metallurgy |
Abraham Darby II, son of the blast furnace innovator, managed to convert pig iron to bar iron in 1749, but no details are known of his process. The Cranage brothers, also working alongside the River Severn, allegedly achieved this experimentally by using a coal-fired reverbatory furnace, in which the iron and the sulphurous coal could be kept separate but it was never used commercially. They were the first to hypothesise that iron could be converted from pig iron to bar iron by the action of heat alone. Although they were unaware of the necessary effects of the oxygen supplied by the air, they had at least abandoned the previous misapprehension that mixture with materials from the fuel were needed. Their experiments were successful and they were granted patent Nº851 in 1766, but no commercial adoption seems to have been made of their process.
In 1783, Peter Onions at Dowlais constructed a larger reverbatory furnace. He began successful commercial puddling with this and was granted patent Nº1370. The furnace was improved by Henry Cort at Fontley in Hampshire in 1783–84 and patented in 1784. Cort added dampers to the chimney, avoiding some of the risk of overheating and burning the iron. Corts process consisted of stirring molten pig iron in a reverberatory furnace in an oxidising atmosphere, thus decarburising it. When the iron "came to nature", that is, to a pasty consistency, it was gathered into a puddled ball, shingled, and rolled (as described below). This application of grooved rollers to the rolling mill, to roll narrow bars, was also Corts adoption of existing rolling mills on the Continent. Cort's efforts to license this process were unsuccessful as it only worked with charcoal smelted pig iron. Modifications were made by Richard Crawshay at his ironworks at Cyfarthfa in Merthyr Tydfil, which incorporated an initial refining process developed at their neighbours at Dowlais.
Ninety years after Cort's invention, an American labor newspaper recalled the advantages of his system:
Corts process (as patented) only worked for white cast iron, not grey cast iron, which was the usual feedstock for forges of the period. This problem was resolved probably at Merthyr Tydfil by combining puddling with one element of a slightly earlier process. This involved another kind of hearth known as a refinery or running out fire. The pig iron was melted in this and run out into a trough. The slag separated, and floated on the molten iron, and was removed by lowering a dam at the end of the trough. The effect of this process was to desiliconise the metal, leaving a white brittle metal, known as finers metal. This was the ideal material to charge to the puddling furnace. This version of the process was known as dry puddling' and continued in use in some places as late as 1890.
An additional development in refining gray iron was known as wet puddling, also known as boiling or pig boiling. This was invented by a puddler named Joseph Hall at Tipton. He began adding scrap iron to the charge. Later, he tried adding iron scale (in effect, iron oxides such as FeO, , or ). The result was spectacular in that the furnace boiled violently, producing carbon monoxide bubbles. This was due to a chemical reaction between the iron oxides in the scale and the carbon dissolved in the pig iron: . To his surprise, the resultant puddle ball produced good iron.
One big problem with puddling was that up to 15% of the iron was drawn off with the slag because sand was used for the bed. Hall substituted roasted tap cinder for the bed, which cut this waste to 8%, declining to 5% by the end of the century.
Hall subsequently became a partner in establishing the Bloomfield Iron Works at Tipton in 1830, the firm becoming Bradley, Barrows and Hall from 1834. This is the version of the process most commonly used in the mid to late 19th century. Wet puddling had the advantage that it was much more efficient than dry puddling (or any earlier process). The best yield of iron achievable from dry puddling is one ton of iron from 1.3 tons of pig iron (a yield of 77%), but the yield from wet puddling was nearly 100%.
The production of mild steel in the puddling furnace was achieved circa 1850 in Westphalia, Germany and was patented in Great Britain on behalf of Lohage, Bremme and Lehrkind. It worked only with pig iron made from certain kinds of ore. The cast iron had to be melted quickly and the slag to be rich in manganese. When the metal came to nature, it had to be removed quickly and shingled before further decarburization occurred. The process was taken up at the Low Moor Ironworks at Bradford in Yorkshire (England) in 1851 and in the Loire valley in France in 1855. It was widely used.
The puddling process began to be displaced with the introduction of the Bessemer process, which produced steel. This could be converted into wrought iron using the Aston process for a fraction of the cost and time. For comparison, an average size charge for a puddling furnace was while a Bessemer converter charge was (13,600 kg). The puddling process could not be scaled up, being limited by the amount that the puddler could handle. It could only be expanded by building more furnaces. | 0 | Metallurgy |
In biochemical signaling, diacylglycerol functions as a second messenger signaling lipid, and is a product of the hydrolysis of the phospholipid phosphatidylinositol 4,5-bisphosphate (PIP) by the enzyme phospholipase C (PLC) (a membrane-bound enzyme) that, through the same reaction, produces inositol trisphosphate (IP). Although inositol trisphosphate diffuses into the cytosol, diacylglycerol remains within the plasma membrane, due to its hydrophobic properties. IP stimulates the release of calcium ions from the smooth endoplasmic reticulum, whereas DAG is a physiological activator of protein kinase C (PKC). The production of DAG in the membrane facilitates translocation of PKC from the cytosol to the plasma membrane. | 1 | Gene expression + Signal Transduction |
Paired receptors transduce extracellular signals through opposing intracellular signaling pathways. Canonically, inhibitory receptors recruit phosphatases through their ITIM motifs, inhibiting the function of cells in which they are expressed. By contrast, activating receptors interact with adaptor proteins such as DAP-12 bearing an ITAM motif, which in turn recruit kinases such as Syk and ZAP70.
Ligands for paired receptors can be very diverse. They are often proteins; the best-characterized are the MHC class I molecules, but a number of other endogenous molecules have been described as ligands for at least one family of paired receptors, and in a few cases in the LILR family, even intact bacteria or viruses can serve as ligands. Lipids such as phosphatidylethanolamine and phosphatidylserine, sugars and sialylated glycans, and nucleic acids can all serve as ligands for some paired receptors.
The binding affinity of paired receptors' extracellular domains for their ligands is generally fairly weak, with dissociation constants (K) in the micromolar (μM) range. However, the inhibitory member of a pair usually binds with higher affinity than the activating member. This can produce a competitive inhibition effect, in which the inhibitory member of the pair out-competes its activating counterpart for ligand binding; other mechanisms of interference with activation, such as disrupting dimerization, have also been described. Thus the net baseline signal from the pair is usually inhibitory, but may be modulated through differences in expression, surface density, subcellular localization, or other factors.
In NK cells, ligands for inhibitory receptors are often MHC class I (MHC-I) molecules, while those for activating receptors may include signals of abnormality or infection such as proteins from pathogens or tumors, or molecules associated with cell stress. Endogenous ligands for inhibitory receptors are better characterized than those for activating receptors. Paired receptor signaling may represent maintenance of homeostasis such that immune responses to normal host cells are inhibited, while responses to abnormal or pathogenic molecules in the environment are activating. NK activation in the absence of inhibitory receptor signals from endogenous ligands is a molecular mechanism for the missing-self hypothesis of NK activation. | 1 | Gene expression + Signal Transduction |
Preventative measures have been recommended that are intended to decrease the risk of accidental ingestion of caustic substances including:
* Keeping caustic substances in locked cabinets or on upper shelves
* Not storing chemical substances in food or drink containers
* Not keeping large amounts of detergent in the home
* Not mentioning a drug as "candy" when giving it as medication
* Keeping the phone number for poison control in the home
* Keeping caustic substances in labelled containers | 0 | Metallurgy |
In some cases the presence of flux is undesirable; flux traces interfere with e.g. precision optics or MEMS assemblies. Flux residues also tend to outgas in vacuum and space applications, and traces of water, ions and organic compounds may adversely affect long-term reliability of non-hermetic packages. Trapped flux residues are also the cause of most voids in the joints. Flux-less techniques are therefore desirable there.
For successful soldering and brazing, the oxide layer has to be removed from both the surfaces of the materials and the surface of the filler metal preform; the exposed surfaces also have to be protected against oxidation during heating. Flux-coated preforms can also be used to eliminate flux residue entirely from the soldering process.
Protection of the surfaces against further oxidation is relatively simple, by using vacuum or inert atmosphere. Removal of the native oxide layer is more troublesome; physical or chemical cleaning methods have to be employed and the surfaces can be protected by e.g. gold plating. The gold layer has to be sufficiently thick and non-porous to provide protection for reasonable storage time. Thick gold metallization also limits choice of soldering alloys, as tin-based solders dissolve gold and form brittle intermetallics, embrittling the joint. Thicker gold coatings are usually limited to use with indium-based solders and solders with high gold content.
Removal of the oxides from the solder preform is also troublesome. Fortunately some alloys are able to dissolve the surface oxides in their bulk when superheated by several degrees above their melting point; the Sn-Cu and Sn-Ag require superheating by 18–19 °C, the Sn-Sb requires as little as 10 °C, but the Sn-Pb alloy requires 77 °C above its melting point to dissolve its surface oxide. The self-dissolved oxide degrades the solder's properties and increases its viscosity in molten state, however, so this approach is not optimal.
Solder preforms are preferred to be with high volume-to-surface ratio, as that limits the amount of oxide being formed. Pastes have to contain smooth spherical particles, preforms are ideally made of round wire. Problems with preforms can be also sidestepped by depositing the solder alloy directly on the surfaces of the parts or substrates, by chemical or electrochemical means for example.
A protective atmosphere with chemically reducing properties can be beneficial in some cases. Molecular hydrogen can be used to reduce surface oxides of tin and indium at temperatures above 430 and 470 °C; for zinc the temperature is above 500 °C, where zinc is already becoming volatilized. (At lower temperatures the reaction speed is too slow for practical applications.) Very low partial pressures of oxygen and water vapor have to be achieved for the reaction to proceed.
Other reactive atmospheres are also in use. Vapors of formic acid and acetic acid are the most commonly used. Carbon monoxide and halogen gases (for example carbon tetrafluoride, sulfur hexafluoride, or dichlorodifluoromethane) require fairly high temperatures for several minutes to be effective.
Atomic hydrogen is much more reactive than molecular hydrogen. In contact with surface oxides it forms hydroxides, water, or hydrogenated complexes, which are volatile at soldering temperatures. A practical dissociation method is an electrical discharge. Argon-hydrogen gas compositions with hydrogen concentration below the low flammable limit can be used, eliminating the safety issues. The operation has to be performed at low pressure, as the stability of atomic hydrogen at atmospheric pressure is insufficient. Such hydrogen plasma can be used for fluxless reflow soldering.
Active atmospheres are relatively common in furnace brazing; due to the high process temperatures the reactions are reasonably fast. The active ingredients are usually carbon monoxide (possibly in the form of combusted fuel gas) and hydrogen. Thermal dissociation of ammonia yields an inexpensive mixture of hydrogen and nitrogen.
Bombardment with atomic particle beams can remove surface layers at a rate of tens of nanometers per minute. The addition of hydrogen to the plasma augments the removal efficiency by chemical mechanisms.
Mechanical agitation is another possibility for disrupting the oxide layer. Ultrasound can be used for assisting tinning and soldering; an ultrasonic transducer can be mounted on the soldering iron, in a solder bath, or in the wave for wave soldering. The oxide disruption and removal involves cavitation effects between the molten solder and the base metal surface. A common application of ultrasound fluxing is in tinning of passive parts (active parts do not cope well with the mechanical stresses involved); even aluminium can be tinned this way. The parts can then be soldered or brazed conventionally.
Mechanical rubbing of a heated surface with molten solder can be used for coating the surface. Both surfaces to be joined can be prepared this way, then placed together and reheated. This technique was formerly used to repair small damages on aluminium aircraft skins.
A very thin layer of zinc can be used for joining aluminium parts. The parts have to be perfectly machined, or pressed together, due to the small volume of filler metal. At high temperature applied for long time, the zinc diffuses away from the joint. The resulting joint does not present a mechanical weakness and is corrosion-resistant. The technique is known as diffusion soldering.
Fluxless brazing of copper alloys can be done with self-fluxing filler metals. Such metals contain an element capable of reaction with oxygen, usually phosphorus. A good example is the family of copper-phosphorus alloys. | 0 | Metallurgy |
The amount of transcription factories found per nucleus appears to be determined by cell type, species and the type of measurement. Cultured mouse embryonic fibroblasts have been found to have roughly 1500 factories through immunofluorescence detection of RNAP II however cells taken from different tissues of the same mouse group had between 100 and 300 factories. Measurements of the number of transcription factories in HeLa cells give a varied result. For example, using the traditional fluorescence microscopy approach 300 – 500 factories were found but using both confocal and electron microscopy roughly 2100 were detected. | 1 | Gene expression + Signal Transduction |
Anodizing will raise the surface since the oxide created occupies more space than the base metal converted. This will generally not be of consequence except where there are tight tolerances. If so, the thickness of the anodizing layer has to be taken into account when choosing the machining dimension. A general practice on engineering drawing is to specify that "dimensions apply after all surface finishes". This will force the machine shop to take into account the anodization thickness when performing the final machining of the mechanical part before anodization. Also in the case of small holes threaded to accept screws, anodizing may cause the screws to bind, thus the threaded holes may need to be chased with a tap to restore the original dimensions. Alternatively, special oversize taps may be used to precompensate for this growth. In the case of unthreaded holes that accept fixed-diameter pins or rods, a slightly oversized hole to allow for the dimension change may be appropriate. Depending on the alloy and thickness of the anodized coating, the same may have a significantly negative effect on fatigue life. Conversely, anodizing may increase fatigue life by preventing corrosion pitting. | 0 | Metallurgy |
Research on thyroid cancer has elucidated the theory that paracrine signaling may aid in creating tumor microenvironments. Chemokine transcription is upregulated when Ras is in the GTP-bound state. The chemokines are then released from the cell, free to bind to another nearby cell. Paracrine signaling between neighboring cells creates this positive feedback loop. Thus, the constitutive transcription of upregulated proteins form ideal environments for tumors to arise. Effectively, multiple bindings of ligands to the RTK receptors overstimulates the Ras-Raf-MAPK pathway, which overexpresses the mitogenic and invasive capacity of cells. | 1 | Gene expression + Signal Transduction |
Viral RdRps were discovered in the early 1960s from studies on mengovirus and polio virus when it was observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA-directed RNA synthesis. This lack of sensitivity suggested that there is a virus-specific enzyme that could copy RNA from an RNA template and not from a DNA template. | 1 | Gene expression + Signal Transduction |
The raw material was bar iron, or (from the introduction of mild steel in the late 19th century), a bar of steel. This was drawn into a flat bar (known as a tin bar) at the ironworks or steel works where it was made. The cross-section of the bar needed to be accurate in size as this would be the cross-section of the pack of plates made from it. The bar was cut to the correct length (being the width of the plates) and heated. It was then passed four or five times through the rolls of the rolling mill, to produce a thick plate about 30 inches long. Between each pass the plate is passed over (or round) the rolls, and the gap between the rolls is narrowed by means of a screw.
This was then rolled until it had doubled in length. The plate was then folded in half (doubled) using a doubling shear, which was like a table where one half of the surface folds over on top of the other. It is then put into a furnace to be heated until it is well soaked. This is repeated until there is a pack of 8 or 16 plates. The pack is then allowed to cool. When cool, the pack was sheared (using powered shears) and the plates separated by openers (usually women). Defective plates were discarded, and the rest passed to the pickling department.
In the pickling department, the plates were immersed in baths of acid (to remove scale, i.e., oxide), then in water (washing them). After inspection they were placed in an annealing furnace, where they were heated for 10–14 hours. This was known as black pickling and black annealing. After being removed they were allowed to cool for up to 48 hours. The plates were then rolled cold through highly polished rolls to remove any unevenness and give them a polished surface. They were then annealed again at a lower temperature and pickled again, this being known as white annealing and white pickling. They were then washed and stored in slightly acid water (where they would not rust) awaiting tinning.
The tinning set consisted of two pots with molten tin (with flux on top) and a grease pot. The flux dries the plate and prepares it for the tin to adhere. The second tin pot (called the wash pot) had tin at a lower temperature. This is followed by the grease pot (containing an oil), removing the excess tin. Then follow cleaning and polishing processes. Finally, the tinplates were packed in boxes of 112 sheets ready for sale. Single plates were 14 inches by 20 inches; doubles twice that. A box weighed approximately a hundredweight.
What is described here is the process as employed during the 20th century. The process grew somewhat in complexity with the passage of time, as gradually it was found that the inclusion of additional procedures improved quality. The practice of hot rolling and then cold rolling evidently goes back to the early days, as the Knight family's tinplate works had (from its foundation in about 1740) two rolling mills, one at Bringewood (west of Ludlow) which made blackplate, and the other the tin mill at Mitton (now part of Stourport), evidently for the later stages. | 0 | Metallurgy |
Microstructure generation is also known as stochastic microstructure reconstruction.
Computer-simulated microstructures are generated to replicate the microstructural features of actual microstructures. Such microstructures are referred to as synthetic microstructures. Synthetic microstructures are used to investigate what microstructural feature is important for a given property. To ensure statistical equivalence between generated and actual microstructures, microstructures are modified after generation to match the statistics of an actual microstructure. Such procedure enables generation of theoretically infinite number of computer simulated microstructures that are statistically the same (have the same statistics) but stochastically different (have different configurations). | 0 | Metallurgy |