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There is evidence from a phylogenetically diverse sample of tunicates (Urochordata) that AGA and AGG code for glycine. In other organisms, AGA/AGG code for either arginine or serine and in vertebrate mitochondria they code a STOP. Evidence for glycine translation of AGA/AGG was first found in 1993 in Pyura stolonifera and Halocynthia roretzi. It was then confirmed by tRNA sequencing and sequencing whole mitochondrial genomes. | 1 | Gene expression + Signal Transduction |
The usual process of electrorefining copper consists of placing a copper anode (about 99.5–99.7% pure copper) in sulfuric acid (HSO) bath of copper electrolyte, together with a cathode, and passing a current between the anode and cathode through an external circuit. At the applied electropotential, copper and less noble elements dissolve in the electrolyte, while elements more noble than copper, such as gold (Au) and silver (Ag), do not. Under the influence of the applied electrical potential, copper ions migrate from the anode and deposit on the cathode, forming cathode copper.
The current IsaKidd technology represents the merger of the copper refining technologies developed by the two different organisations. The initial Isa Process development in the late 1970s, with its reusable stainless-steel cathode starter sheets, represented an advance on the previous technology of single-use starter sheets of pure copper, the production of which was a labour-intensive process.
The production of the single-use starter sheets involved laying down a sheet of copper by electrolysis on each side of a “mother plate”. Generating the sheet took a day, and thousands of sheets could be needed every day. Originally, the copper starter sheets were separated from the mother plate manually, but over time the process was automated. In addition, limitations associated with the use of copper starter sheets meant that it was difficult to meet the purity specifications of some new copper applications that were, in the 1970s and 1980s, demanding higher quality copper. | 0 | Metallurgy |
General transcription factors (GTFs) or basal transcription factors are protein transcription factors that have been shown to be important in the transcription of class II genes to mRNA templates. Many of them are involved in the formation of a preinitiation complex, which, together with RNA polymerase II, bind to and read the single-stranded DNA gene template. The cluster of RNA polymerase II and various transcription factors is known as a basal transcriptional complex (BTC). | 1 | Gene expression + Signal Transduction |
The open and closed conformations refer to the state of the DNA and whether the template strand has been separated from the non-template strand within the PIC. The place at which the DNA opens to form the bubble lies above a tunnel that is lined by the B-core, B-linker and B-reader as well as parts of RNA polymerase II. The B linker is found directly aligned with the point at which the DNA opens and in the open complex it is found between the two DNA strands, suggesting that it has a role in promoter melting, but it does not have a role in the catalytic RNA synthesis. Although TFIIB keeps a similar structure in both conformations some of the intramolecular interactions between the core and the B reader are disrupted upon DNA opening.
After DNA melting the transcription initiator (Inr) must be located on the DNA so the TSS can be identified by the RNA polymerase II and transcription can begin. This is done by passing the DNA through the template tunnel and the DNA is scanned, looking for the Inr and placing it in a position that ensures the transcription start site is located in the correct place by the RNA polymerase active site. The B reader of TFIIB is found in the template tunnel and is important in locating the Inr, mutations in the B reader cause the TSS to change and therefore incorrect transcription to occur (although PIC formation and DNA melting still take place). Yeast are a particularly good example of this alignment as the yeast Inr motif has a strictly conserved A residue at position 28 and in the open complex model a complementary T residue can be found in the B reader helix. When this T residue is mutated, transcription was significantly less effective emphasizing the role of the B reader.
The B reader loop is further thought to stabilise NTPs in the active site and, due to its flexibility, allow the nucleic acids to remain in contact during the early synthesis of the RNA molecule (i.e. stabilises the growing RNA-DNA hybrid) | 1 | Gene expression + Signal Transduction |
Andrew Carnegie, a Scottish immigrant, advanced the cheap and efficient mass production of steel rails for railroad lines, by adopting the Bessemer process. After an early career in railroads, Carnegie foresaw the potential for steel to amass vast profits. He asked his cousin, George Lauder to join him in America from Scotland. Lauder was a leading mechanical engineer who had studied under Lord Kelvin. Lauder devised several new systems for the Carnegie Steel Company including the process for washing and coking dross from coal mines, which resulted in a significant increase in scale, profits, and enterprise value.
Lauder would go on to lead the development of the use of steel in armor and armaments for the Carnegie Steel Company, spending significant time at the Krupp factory in Germany in 1886 before returning to build the massive armor plate mill at the Homestead Steel Works that would revolutionize naval warfare.
Carnegies first mill was the Edgar Thomson Works in Braddock, PA, just outside of Pittsburgh. In 1888, he bought the rival Homestead Steel Works, which included an extensive plant served by tributary coal and iron fields, a 425-mile (685 km) long railway, and a line of lake steamships. He would also add the Duquesne Works to his empire. These three mills on the Monongahela River would make Pittsburgh the steel capital of the world. In the late 1880s, the Carnegie Steel Company was the largest manufacturer of pig iron, steel rails, and coke in the world, with a capacity to produce approximately 2,000 tons of pig iron per day. A consolidation of Carnegies assets and those of his associates occurred in 1892 with the launching of the Carnegie Steel Company.
Lauder would go on to lead the development of the use of steel in armor and armaments for the Carnegie Steel Company, spending significant time at the Krupp factory in Germany in 1886 before returning to build the massive armor plate mill at the Homestead Steel Works that would revolutionize naval warfare.
By 1889, the U.S. output of steel exceeded that of Britain, and Andrew Carnegie owned a large part of it. By 1900, the profits of Carnegie Bros. & Company alone stood at $480,000,000 with $225,000,000 being Carnegie's share.
Carnegie, through Keystone, supplied the steel for and owned shares in the landmark Eads Bridge project across the Mississippi River in St. Louis, Missouri (completed 1874). This project was an important proof-of-concept for steel technology which marked the opening of a new steel market.
The Homestead Strike was a violent labor dispute in 1892 that involved an attack by strikers against private security guards. The governor called in the National Guard. The strike failed and the union collapsed. The dispute took place at Carnegie's Homestead Steel Works between the Amalgamated Association of Iron and Steel Workers and the Carnegie Steel Company. The final result was a major defeat for the union and a setback for efforts to unionize steelworkers.
Carnegie sold all his steel holdings in 1901; they were merged into U.S. Steel and it was non-union until the late 1930s. | 0 | Metallurgy |
The iron pillar in India was produced by the forge welding of pieces of wrought iron. In a report published in the journal Current Science, R. Balasubramaniam of the IIT Kanpur explains how the pillar's resistance to corrosion is due to a passive protective film at the iron-rust interface. The presence of second-phase particles (slag and unreduced iron oxides) in the microstructure of the iron, that of high amounts of phosphorus in the metal, and the alternate wetting and drying existing under atmospheric conditions are the three main factors in the three-stage formation of that protective passive film.
Lepidocrocite and goethite are the first amorphous iron oxyhydroxides that appear upon oxidation of iron. High corrosion rates are initially observed. Then, an essential chemical reaction intervenes slag and unreduced iron oxides (second phase particles) in the iron microstructure alter the polarisation characteristics and enrich the metal–scale interface with phosphorus, thus indirectly promoting passivation of the iron (cessation of rusting activity).
The second-phase particles act as a cathode, and the metal itself serves as anode, for a mini-galvanic corrosion reaction during environment exposure. Part of the initial iron oxyhydroxides is also transformed into magnetite, which somewhat slows down the process of corrosion. The ongoing reduction of lepidocrocite and the diffusion of oxygen and complementary corrosion through the cracks and pores in the rust still contribute to the corrosion mechanism from atmospheric conditions.
The next main agent to intervene in protection from oxidation is phosphorus, enhanced at the metal–scale interface by the same chemical interaction previously described between the slags and the metal. The ancient Indian smiths did not add lime to their furnaces. The use of limestone as in modern blast furnaces yields pig iron that is later converted into steel; in the process, most phosphorus is carried away by the slag.
The absence of lime in the slag and the use of specific quantities of wood with high phosphorus content (for example, Cassia auriculata) during the smelting induces a higher phosphorus content (> 0.1%, average 0.25%) than in modern iron produced in blast furnaces (usually less than 0.05%).
This high phosphorus content and particular repartition are essential catalysts in the formation of a passive protective film of misawite (d-FeOOH), an amorphous iron oxyhydroxide that forms a barrier by adhering next to the interface between metal and rust. Misawite, the initial corrosion-resistance agent, was thus named because of the pioneering studies of Misawa and co-workers on the effects of phosphorus and copper and those of alternating atmospheric conditions in rust formation.
The most critical corrosion-resistance agent is iron hydrogen phosphate hydrate (FePO-HPO-4HO) under its crystalline form and building up as a thin layer next to the interface between metal and rust. Rust initially contains iron oxide/oxyhydroxides in their amorphous forms. Due to the initial corrosion of metal, there is more phosphorus at the metal–scale interface than in the bulk of the metal. Alternate environmental wetting and drying cycles provide the moisture for phosphoric-acid formation. Over time, the amorphous phosphate is precipitated into its crystalline form (the latter being therefore an indicator of old age, as this precipitation is a rather slow happening). The crystalline phosphate eventually forms a continuous layer next to the metal, which results in an excellent corrosion resistance layer. In 1,600 years, the film has grown just one-twentieth of a millimetre thick.
In 1969, in his first book, Chariots of the Gods?, Erich von Däniken cited the absence of corrosion on the Delhi pillar and the unknown nature of its creation as evidence of extraterrestrial visitation. When informed by an interviewer, in 1974, that the column was not in fact rust-free, and that its method of construction was well-understood, von Däniken responded that he no longer considered the pillar or its creation to be a mystery.
Balasubramaniam states that the pillar is "a living testimony to the skill of metallurgists of ancient India". An interview with Balasubramaniam and his work can be seen in the 2005 article by the writer and editor Matthew Veazey. Further research published in 2009 showed that corrosion has developed evenly over the surface of the pillar.
It was claimed in the 1920s that iron manufactured in Mirjati near Jamshedpur is similar to the iron of the Delhi pillar. Further work on Adivasi (tribal) iron by the National Metallurgical Laboratory in the 1960s did not verify this claim. | 0 | Metallurgy |
The nodes of Ranvier Na+/Ca2+ exchangers and high density of voltage-gated Na+ channels that generate action potentials. A sodium channel consists of a pore-forming α subunit and two accessory β subunits, which anchor the channel to extra-cellular and intra-cellular components. The nodes of Ranvier in the central and peripheral nervous systems mostly consist of αNaV1.6 and β1 subunits. The extra-cellular region of β subunits can associate with itself and other proteins, such as tenascin R and the cell-adhesion molecules neurofascin and contactin. Contactin is also present at nodes in the CNS and interaction with this molecule enhances the surface expression of Na+ channels.
Ankyrin has been found to be bounded to βIV spectrin, a spectrin isoform enriched at nodes of Ranvier and axon initial segments. The PNS nodes are surrounded by Schwann cell microvilli, which contain ERMs and EBP50 that may provide a connection to actin microfilaments. Several extracellular matrix proteins are enriched at nodes of Ranvier, including tenascin-R, Bral-1, and proteoglycan NG2, as well as phosphacan and versican V2. At CNS nodes, the axonal proteins also include contactin; however, Schwann cell microvilli are replaced by astrocyte perinodal extensions. | 1 | Gene expression + Signal Transduction |
Rust removal from small iron or steel objects by electrolysis can be done in a home workshop using simple materials such as a plastic bucket filled with an electrolyte consisting of washing soda dissolved in tap water, a length of rebar suspended vertically in the solution to act as an anode, another laid across the top of the bucket to act as a support for suspending the object, baling wire to suspend the object in the solution from the horizontal rebar, and a battery charger as a power source in which the positive terminal is clamped to the anode and the negative terminal is clamped to the object to be treated which becomes the cathode. Hydrogen and oxygen gases are produced at the cathode and annode respectively. This mixture is flammable/explosive. Care should also be taken to avoid hydrogen embrittlement. Overvoltage also produces small amounts of ozone, which is highly toxic, so a low voltage phone charger is a far safer source of DC current. Hydrogens effects on global warming have also recently come under scrutiny.
Rust may be treated with commercial products known as rust converter which contain tannic acid or phosphoric acid which combines with rust; removed with organic acids like citric acid and vinegar or the stronger hydrochloric acid; or removed with chelating agents as in some commercial formulations or even a solution of molasses. | 0 | Metallurgy |
E. coli is one of the most widely used expression hosts, and DNA is normally introduced in a plasmid expression vector. The techniques for overexpression in E. coli are well developed and work by increasing the number of copies of the gene or increasing the binding strength of the promoter region so assisting transcription.
For example, a DNA sequence for a protein of interest could be cloned or subcloned into a high copy-number plasmid containing the lac (often LacUV5) promoter, which is then transformed into the bacterium E. coli. Addition of IPTG (a lactose analog) activates the lac promoter and causes the bacteria to express the protein of interest.
E. coli strain BL21 and BL21(DE3) are two strains commonly used for protein production. As members of the B lineage, they lack lon and OmpT proteases, protecting the produced proteins from degradation. The DE3 prophage found in BL21(DE3) provides T7 RNA polymerase (driven by the LacUV5 promoter), allowing for vectors with the T7 promoter to be used instead. | 1 | Gene expression + Signal Transduction |
KaiC is a gene belonging to the KaiABC gene cluster (with KaiA, and KaiB) that, together, regulate bacterial circadian rhythms, specifically in cyanobacteria. KaiC encodes for the KaiC protein, which interacts with the KaiA and KaiB proteins in a post-translational oscillator (PTO). The PTO is cyanobacteria master clock that is controlled by sequences of phosphorylation of KaiC protein. Regulation of KaiABC expression and KaiABC phosphorylation is essential for cyanobacteria circadian rhythmicity, and is particularly important for regulating cyanobacteria processes such as nitrogen fixation, photosynthesis, and cell division. Studies have shown similarities to Drosophila, Neurospora, and mammalian clock models in that the kaiABC regulation of the cyanobacteria slave circadian clock is also based on a transcription translation feedback loop (TTFL). KaiC protein has both auto-kinase and auto-phosphatase activity and functions as the circadian regulator in both the PTO and the TTFL. KaiC has been found to not only suppress kaiBC when overexpressed, but also suppress circadian expression of all genes in the cyanobacterial genome. | 1 | Gene expression + Signal Transduction |
Another problem with plotting this (or any) type of count data is [http://en.wiktionary.org/wiki/overplotting overplotting] which is solved in the RA plot by jittering the points out away from each other but no so far as to merge with other coordinates. The result of this feature is a patchwork-like appearance to the plot that fades away as the A increases. | 1 | Gene expression + Signal Transduction |
The direct reduction of iron ore principle was tested in the late 19th century using high-temperature stirring of ore powder mixed with coal and a small amount of limestone to adjust the ores acidity. Carl Wilhelm Siemens direct reduction process, which was sporadically employed in the United States and United Kingdom in the 1880s, is particularly noteworthy. This process is based on using a 3-meter in diameter and similarly lengthy drum with a horizontal axis for blowing gases preheated by two regenerators.
The metallurgy industry underwent much research regarding the implementation of rotary tubular furnaces, inspired by similar equipment used in cement works. The Basset process, developed during the 1930s, is capable of even producing molten cast iron. In the 1920s, German metallurgist , head of the metallurgy department at the and professor at the Clausthal University of Technology, explored the metallurgical applications of this type of furnace. He filed a series of patents for removing volatile metals from steel raw materials.
During the 1930s Johannsen initiated the development of direct-reduction iron production. The first installation underwent testing from 1931 to 1933 at the Gruson plant in Magdeburg. Research on the Krupp-Renn process continued until 1939 at the Krupp facility in Essen-Borbeck. The process, named after the Krupp company that created it and the , translating to "low furnace," displayed potential. As a result, Krupp procured patents overseas to safeguard the invention after 1932. | 0 | Metallurgy |
Antibody diversity is produced by genetic rearrangement after shuffling and rejoining one of each of the various gene segments for the heavy and light chains. Due to mixing and random recombination of the gene segments errors can occur at the sites where gene segments join with each other. These errors are one of the sources of the antibody diversity that is commonly observed in both the light and heavy chains. Moreover, when B cells continue to proliferate, mutations accumulate at the variable regions through a process called somatic hypermutation. The high concentrations of these mutations at the variable region also produce high antibody diversity. | 1 | Gene expression + Signal Transduction |
The discovery of introns and the split gene architecture of the eukaryotic genes started a new era of eukaryotic biology. The question of why eukaryotic genes had fragmented genes prompted speculation and discussion almost immediately.
Ford Doolittle published a paper in 1978 in which he stated that most molecular biologists assumed that the eukaryotic genome arose from a ‘simpler’ and more ‘primitive’ prokaryotic genome rather like that of Escherichia coli. However, this type of evolution would require that introns be introduced into the coding sequences of bacterial genes. Regarding this requirement, Doolittle said, “It is extraordinarily difficult to imagine how informationally irrelevant sequences could be introduced into pre-existing structural genes without deleterious effects.” He stated “I would like to argue that the eukaryotic genome, at least in that aspect of its structure manifested as ‘genes in pieces’ is in fact the primitive original form.”
James Darnell expressed similar views in 1978. He stated, “The differences in the biochemistry of messenger RNA formation in eukaryotes compared to prokaryotes are so profound as to suggest that sequential prokaryotic to eukaryotic cell evolution seems unlikely. The recently discovered non-contiguous sequences in eukaryotic DNA that encode messenger RNA may reflect an ancient, rather than a new, distribution of information in DNA and that eukaryotes evolved independently of prokaryotes.”
However, in an apparent attempt to reconcile with the idea that RNA preceded DNA in evolution, and with the concept of the three evolutionary lineages of archea, bacteria and eukarya, both Doolittle and Darnell deviated from their original speculation in a joint paper in 1985. They suggested that the ancestor of all three groups of organisms, the ‘progenote,’ had a genes-in-pieces structure, from which all three lineages evolved. They speculated that the precellular stage had primitive RNA genes which had introns, which were reverse transcribed into DNA and formed the progenote. Bacteria and archea evolved from the progenote by losing introns, and ‘urkaryote’ evolved from it by retaining introns. Later, the eukaryote evolved from the urkaryote by evolving a nucleus and absorbing mitochondria from bacteria. Multicellular organisms then evolved from the eukaryote.
These authors predicted that the distinctions between the prokaryote and the eukaryote were so profound that the prokaryote to eukaryote evolution was not tenable, and had different origins. However, other than the speculations that the precellular RNA genes must have had introns, they did not address the key questions of intron origin. No explanations described why exons were short and introns were long, how the splice junctions originated, what the structure and sequence of the splice junctions meant, and why eukaryote genomes were large.
Around the same time that Doolittle and Darnell suggested that introns in eukaryotic genes could be ancient, Colin Blake and Walter Gilbert published their views on intron origins independently. In their view, introns originated as spacer sequences that enabled convenient recombination and shuffling of exons that encoded distinct functional domains in order to evolve new genes. Thus, new genes were assembled from exon modules that coded for functional domains, folding regions, or structural elements from preexisting genes in the genome of an ancestral organism, thereby evolving genes with new functions. They did not specify how exons or introns originated. In addition, even after many years, extensive analysis of thousands of proteins and genes showed that only extremely rarely do genes exhibit the supposed exon shuffling phenomenon. Furthermore, molecular biologists questioned the exon shuffling proposal, from a purely evolutionary view for both methodological and conceptual reasons, and, in the long run, this theory did not survive. | 1 | Gene expression + Signal Transduction |
Alclad sheeting has become a widely used material within the aviation industry for the construction of aircraft due to its favourable qualities, such as a high fatigue resistance and its strength. During the first half of the twentieth century, substantial studies were conducted into the corrosion qualities of various lightweight aluminium alloys for aviation purposes. The first aircraft to be constructed from Alclad was the all-metal US Navy airship ZMC-2, which was constructed in 1927 at Naval Air Station Grosse Ile. Prior to this, aluminium had been used on the pioneering zeppelins constructed by Ferdinand Zeppelin.
Alclad has been most commonly present in certain elements of an aircraft, including the fuselage, structural members, skin, and cowls. The aluminium alloy that Alclad is derived from has become one of the most commonly used of all aluminium-based alloys. While unclad aluminium has also continued to be extensively used on modern aircraft, which has a lower weight than Alclad, it is more prone to corrosion; the alternating use of the two materials is often defined by the specific components or elements that are composed of them. In aviation-grade Alclad, the thickness of the outer cladding layer typically varies between 1% and 15% of the total thickness. | 0 | Metallurgy |
Each dislocation is associated with a strain field which contributes some small but finite amount to the materials stored energy. When the temperature is increased - typically below one-third of the absolute melting point - dislocations become mobile and are able to glide, cross-slip and climb. If two dislocations of opposite sign meet then they effectively cancel out and their contribution to the stored energy is removed. When annihilation is complete then only excess dislocation of one kind will remain. | 0 | Metallurgy |
Nanog is a transcription factor that controls both self-renewal and pluripotency of embryonic stem cells. Similarly, the expression of Nanog family proteins is increased in many types of cancer and correlates with a worse prognosis. | 1 | Gene expression + Signal Transduction |
Metallic parts produced by casting are comparatively inexpensive, but are often subject to metallurgical flaws like porosity and microstructural defects. Friction stir processing can be used to introduce a wrought microstructure into a cast component and eliminate many of the defects. By vigorously stirring a cast metal part to homogenize it and reduce the grain size, the ductility and strength are increased. | 0 | Metallurgy |
Loam molding was formerly used for making cast iron or bronze cannon and is still used for casting large bells.
Loam (pronounced low-m) is a mixture of sand and clay with water, sometimes with horse dung (valuable for its straw content), animal hair or coke. The object of including dung or hair was to make the mould permeable and allow gas (such as steam) to escape during casting.
The mold for a cylindrically symmetrical object, such as a cannon, is built up in stages around a spindle, to which is fixed a strickle board with the shape of the eventual casting. The mold also has provision for the casting of a gunhead, beyond the muzzle of the cannon, into which slag can float during casting. If the object is to be hollow, a straw rope is wound around the spindle and covered in a friable material to the dimensions of the exterior of the cannon, the strickle board being turned on the spindle to ensure it is cylindrical. Decorative elements and models of the trunnions are then attached. This is then covered in a thick layer of loam. The mold is then fired. After this the straw rope is then pulled out with the rest of the material used to form the shape of the cannon.
The mould is then mounted vertically in a casting put in front of the furnace. If the cannon is to be cast hollow, a core is mounted in the mould. The furnace was then tapped and metal run into the mold. The mold is then broken off the casting. The gunhead is cut off, and the bore of the cannon reamed out using a boring mill.
The process for the cylinder for a steam engine would be similar. The process for casting a bell is of the same nature, but the procedure is necessarily different. | 0 | Metallurgy |
Based on the results of the pilot plant work, the MIM Holdings Board of Directors approved the construction of an A$65 million demonstration plant, capable of producing 60,000 t/y of lead bullion. This plant operated from early 1991 until 1995. It was initially designed to treat 20 t/h of lead concentrate using lance air enriched to 27%. However, the oxygen originally designated for its use was diverted to the more profitable copper smelting operations, and the feed rate to the lead ISASMELT demonstration plant was severely restricted. When there was sufficient oxygen available in 1993 to increase the enrichment level to 33–35%, treatment rates of up to 36 t/h of concentrate were achieved, with residual lead in the final reduction furnace slag being in the range of 2–5%.
The two-stage approach to ISASMELT lead smelting was partly driven by the relatively low lead content of Mount Isa lead concentrates (typically in the range of 47–52% lead during the lead ISASMELT development period). Trying to produce lead bullion in a single furnace with such low concentrate grades would result in excessive fuming of lead oxide with a huge amount of material that would have to be returned to the furnace to recover the lead and, consequently, a higher energy demand as that material had to be reheated to the furnace temperatures.
Concentrates with higher lead contents can be smelted directly into lead metal in a single furnace without excess fuming. This was demonstrated on the large scale in 1994, when 4000 t of concentrate containing 67% lead were treated at rates up to 32 t/h with lance air enriched to 27%. During these trials, 50% of the lead in the concentrate was converted to lead bullion in the smelting furnace, while most of the rest ended up as lead oxide in the smelting furnace slag.
Like the lead ISASMELT pilot plant, the lead ISASMELT demonstration plant suffered from constraints imposed by the waste gas handling system. In the case of the demonstration plant, the problem was caused by sticky fume that formed an insulating layer on the convection tube bundles of the waste heat boilers, significantly reducing the heat transfer rates and thus the ability of the boilers to reduce the waste gas temperature. As the plant used baghouses to filter lead fume from the waste gas, it was necessary to reduce the temperature of the gas below the point at which the bags would be damaged by high temperatures. The problem was solved by allowing cool air to mix with the hot waste gas to lower the temperature to a level at which the baghouse could operate. This reduced the ISASMELT plant's capacity because it was again limited by the volume of gas that could be filtered by the baghouse.
The lead ISASMELT demonstration plant was mothballed in 1995 because there was insufficient concentrate to keep both it and the rest of the lead smelter operating. It was too small to treat all the Mount Isa lead concentrate by itself. | 0 | Metallurgy |
Tantalum anodizes similarly to titanium and niobium with a range of attractive colours being formed by interference at different film thicknesses. Again the film thickness is dependent on the anodizing voltage and typically ranges from 18 to 23 Angstroms per volt depending on electrolyte and temperature. Uses include tantalum capacitors. | 0 | Metallurgy |
Chromatin remodeling provides fine-tuning at crucial cell growth and division steps, like cell-cycle progression, DNA repair and chromosome segregation, and therefore exerts tumor-suppressor function. Mutations in such chromatin remodelers and deregulated covalent histone modifications potentially favor self-sufficiency in cell growth and escape from growth-regulatory cell signals - two important hallmarks of cancer.
* Inactivating mutations in SMARCB1, formerly known as hSNF5/INI1 and a component of the human SWI/SNF remodeling complex have been found in large number of rhabdoid tumors, commonly affecting pediatric population. Similar mutations are also present in other childhood cancers, such as choroid plexus carcinoma, medulloblastoma and in some acute leukemias. Further, mouse knock-out studies strongly support SMARCB1 as a tumor suppressor protein. Since the original observation of SMARCB1 mutations in rhabdoid tumors, several more subunits of the human SWI/SNF chromatin remodeling complex have been found mutated in a wide range of neoplasms.
* The SWI/SNF ATPase BRG1 (or SMARCA4) is the most frequently mutated chromatin remodeling ATPase in cancer. Mutations in this gene were first recognized in human cancer cell lines derived from lung. In cancer, mutations in BRG1 show an unusually high preference for missense mutations that target the ATPase domain. Mutations are enriched at highly conserved ATPase sequences, which lie on important functional surfaces such as the ATP pocket or DNA-binding surface. These mutations act in a genetically dominant manner to alter chromatin regulatory function at enhancers and promoters.
* Inactivating mutations in BCL7A in Diffuse large B-cell lymphoma (DLBCL) and in other haematological malignancies
* PML-RARA fusion protein in acute myeloid leukemia recruits histone deacetylases. This leads to repression of genes responsible for myelocytes to differentiate, leading to leukemia.
* Tumor suppressor Rb protein functions by the recruitment of the human homologs of the SWI/SNF enzymes BRG1, histone deacetylase and DNA methyltransferase. Mutations in BRG1 are reported in several cancers causing loss of tumor suppressor action of Rb.
* Recent reports indicate DNA hypermethylation in the promoter region of major tumor suppressor genes in several cancers. Although few mutations are reported in histone methyltransferases yet, correlation of DNA hypermethylation and histone H3 lysine-9 methylation has been reported in several cancers, mainly in colorectal and breast cancers.
* Mutations in Histone Acetyl Transferases (HAT) p300 (missense and truncating type) are most commonly reported in colorectal, pancreatic, breast and gastric carcinomas. Loss of heterozygosity in coding region of p300 (chromosome 22q13) is present in large number of glioblastomas.
* Further, HATs have diverse role as transcription factors beside having histone acetylase activity, e.g., HAT subunit, hADA3 may act as an adaptor protein linking transcription factors with other HAT complexes. In the absence of hADA3, TP53 transcriptional activity is significantly reduced, suggesting role of hADA3 in activating TP53 function in response to DNA damage.
* Similarly, TRRAP, the human homolog to yeast Tra1, has been shown to directly interact with c-Myc and E2F1, known oncoproteins. | 1 | Gene expression + Signal Transduction |
Protein phosphatases remove phosphates from proteins, usually on Serine, Threonine, and Tyrosine residues, reversing the action of protein kinases. The PTP family of protein phosphatases is tyrosine-specific, and several other families (PPPL, PPM, HAD) appear to be serine/threonine specific, while other families are unknown or have a variety of substrates (DSPs dephosphorylate any amino acid, while some protein phosphatases also have non-protein substrates). In the human genome, 20 different folds of protein are known to be phosphatases, of which 10 include protein phosphatases.
Protein phosphatomes have been cataloged for human and 8 other key eukaryotes, for Plasmodium and Trypanosomes
and phosphatomes have been used for functional analysis, by experimentally investing all known protein phosphatases, in the yeast Fusarium, in Plasmodium and in human cancer
Large scale databases exist for human and animal phosphatomes [http://phosphatome.net/wiki/index.php Phosphatome.net], parasitic protozoans [http://202.41.10.46/ProtozPhosDB/ ProtozPhosDB] and for the substrates of human phosphatases [http://www.koehn.embl.de/depod/ DEPOD]. | 1 | Gene expression + Signal Transduction |
In many bacteria, both mRNAs and non-coding RNAs can be polyadenylated. This poly(A) tail promotes degradation by the degradosome, which contains two RNA-degrading enzymes: polynucleotide phosphorylase and RNase E. Polynucleotide phosphorylase binds to the 3′ end of RNAs and the 3′ extension provided by the poly(A) tail allows it to bind to the RNAs whose secondary structure would otherwise block the 3′ end. Successive rounds of polyadenylation and degradation of the 3′ end by polynucleotide phosphorylase allows the degradosome to overcome these secondary structures. The poly(A) tail can also recruit RNases that cut the RNA in two. These bacterial poly(A) tails are about 30 nucleotides long.
In as different groups as animals and trypanosomes, the mitochondria contain both stabilising and destabilising poly(A) tails. Destabilising polyadenylation targets both mRNA and noncoding RNAs. The poly(A) tails are 43 nucleotides long on average. The stabilising ones start at the stop codon, and without them the stop codon (UAA) is not complete as the genome only encodes the U or UA part. Plant mitochondria have only destabilising polyadenylation. Mitochondrial polyadenylation has never been observed in either budding or fission yeast.
While many bacteria and mitochondria have polyadenylate polymerases, they also have another type of polyadenylation, performed by polynucleotide phosphorylase itself. This enzyme is found in bacteria, mitochondria, plastids and as a constituent of the archaeal exosome (in those archaea that have an exosome). It can synthesise a 3′ extension where the vast majority of the bases are adenines. Like in bacteria, polyadenylation by polynucleotide phosphorylase promotes degradation of the RNA in plastids and likely also archaea. | 1 | Gene expression + Signal Transduction |
In September 1965, Ordinary National Certificates in science were introduced, in consultation with the Institution, the Royal Institute of Chemistry, the Institute of Physics, the Physical Society, the Institute of Biology, and the Mathematical Association.
In January 1969, these same set of institutions set up the Council of Science and Technology Institutes (CSTI), which ended up as the Science Council in 2003. | 0 | Metallurgy |
An alternative method of decarburising pig iron was the finery forge, which seems to have been devised in the region around Namur in the 15th century. By the end of that century, this Walloon process spread to the Pay de Bray on the eastern boundary of Normandy, and then to England, where it became the main method of making wrought iron by 1600. It was introduced to Sweden by Louis de Geer in the early 17th century and was used to make the oregrounds iron favoured by English steelmakers.
A variation on this was the German forge. This became the main method of producing bar iron in Sweden. | 0 | Metallurgy |
The studies of rapamycin as immunosuppressive agent enabled us to understand its mechanism of action. It inhibits T-cell proliferation and proliferative responses induced by several cytokines, including interleukin 1 (IL-1), IL-2, IL-3, IL-4, IL-6, IGF, PDGF, and colony-stimulating factors (CSFs). Rapamycin inhibitors and rapalogs can target tumor growth both directly and indirectly. Direct impact of them on cancer cells depend on the concentration of the drug and certain cellular characteristics. The indirect way, is based on interaction with processes required for tumor angiogenesis. | 1 | Gene expression + Signal Transduction |
The preinitiation complex (PIC) assembles in a stepwise fashion on the promoter of genes to initiate transcription. The TFIID binds to the TATA box in order to begin the assembly of the TFIIA, recruiting other transcription factors and components needed in the PIC. Data suggests that pRb is able to repress transcription by both pRb being recruited to the promoter as well as having a target present in TFIID.
The presence of pRb may change the conformation of the TFIIA/IID complex into a less active version with a decreased binding affinity. pRb can also directly interfere with their association as proteins, preventing TFIIA/IID from forming an active complex. | 1 | Gene expression + Signal Transduction |
The CCT evolved from the archaeal thermosome ~2Gya, with the two subunits diversifying into multiple units. The CCT changed from having one type of subunit, to having two, three, five, and finally eight types. | 1 | Gene expression + Signal Transduction |
In evolutionary developmental biology, homeosis is the transformation of one organ into another, arising from mutation in or misexpression of certain developmentally critical genes, specifically homeotic genes. In animals, these developmental genes specifically control the development of organs on their anteroposterior axis. In plants, however, the developmental genes affected by homeosis may control anything from the development of a stamen or petals to the development of chlorophyll. Homeosis may be caused by mutations in Hox genes, found in animals, or others such as the MADS-box family in plants. Homeosis is a characteristic that has helped insects become as successful and diverse as they are.
Homeotic mutations work by changing segment identity during development. For example, the Ultrabithorax genotype gives a phenotype wherein metathoracic and first abdominal segments become mesothoracic segments. Another well-known example is Antennapedia: a gain-of-function allele causes legs to develop in the place of antennae.
In botany, Rolf Sattler has revised the concept of homeosis (replacement) by his emphasis on partial homeosis in addition to complete homeosis; this revision is now widely accepted.
Homeotic mutants in angiosperms are thought to be rare in the wild: in the annual plant Clarkia (Onagraceae), homeotic mutants are known where the petals are replaced by a second whorl of sepal-like organs, originating in a mutation of a single gene. The absence of lethal or deleterious consequences in floral mutants resulting in distinct morphological expressions has been a factor in the evolution of Clarkia, and perhaps also in many other plant groups. | 1 | Gene expression + Signal Transduction |
Splicing is dependent on the presence of the 7-methylguanosine cap. A defect in splicing can occur as a result of mutation(s) in the guanylyltransferase, which can inhibit enzyme activity, preventing the formation of the cap. However the severity of the effect is dependent on the guanylyltransferase mutation. Furthermore, the guanylyltransferase relieves transcriptional repression mediated by NELF. NELF together with DSIF prevents transcription elongation. Thus, mutations in the enzyme can affect transcription elongation. | 1 | Gene expression + Signal Transduction |
Metals in their native state are those found in nature as free elements (chemically uncombined). They are usually attached to or mixed with varying amounts of undesired material (gangue), and require only physical separation to produce usable metal.
Most metallic ores in the Earth's crust require chemical processing to produce metal. Oxides and sulfides require smelting. Bauxite, an ore of aluminium, requires electrolysis.
Many metals are found in uncombined metallic form, in varying degrees of purity. These "metals found as metals" are referred to as native metals, which are a subset of native element minerals. The most well-known native metals are native copper and gold. Nonreactive noble metals usually occur in nature as native metals. | 0 | Metallurgy |
RNAs are a type of large biological molecules, whose individual building blocks are called nucleotides. The name poly(A) tail (for polyadenylic acid tail) reflects the way RNA nucleotides are abbreviated, with a letter for the base the nucleotide contains (A for adenine, C for cytosine, G for guanine and U for uracil). RNAs are produced (transcribed) from a DNA template. By convention, RNA sequences are written in a 5′ to 3′ direction. The 5′ end is the part of the RNA molecule that is transcribed first, and the 3′ end is transcribed last. The 3′ end is also where the poly(A) tail is found on polyadenylated RNAs.
Messenger RNA (mRNA) is RNA that has a coding region that acts as a template for protein synthesis (translation). The rest of the mRNA, the untranslated regions, tune how active the mRNA is. There are also many RNAs that are not translated, called non-coding RNAs. Like the untranslated regions, many of these non-coding RNAs have regulatory roles. | 1 | Gene expression + Signal Transduction |
In the 15th century, the finery process, another process which shares the air-blowing principle with the Bessemer process, was developed in Europe. In 1740, Benjamin Huntsman developed the crucible technique for steel manufacture, at his workshop in the district of Handsworth in Sheffield. This process had an enormous impact on the quantity and quality of steel production, but it was unrelated to the Bessemer-type process employing decarburization.
The Japanese may have made use of a Bessemer-type process, which was observed by European travellers in the 17th century. The adventurer Johan Albrecht de Mandelslo describes the process in a book published in English in 1669. He writes, "They have, among others, particular invention for the melting of iron, without the using of fire, casting it into a tun done about on the inside without about half a foot of earth, where they keep it with continual blowing, take it out by ladles full, to give it what form they please." According to historian Donald Wagner, Mandelslo did not personally visit Japan, so his description of the process is likely derived from accounts of other Europeans who had traveled to Japan. Wagner believes that the Japanese process may have been similar to the Bessemer process, but cautions that alternative explanations are also plausible. | 0 | Metallurgy |
The equivalent carbon content concept is used on ferrous materials, typically steel and cast iron, to determine various properties of the alloy when more than just carbon is used as an alloyant, which is typical. The idea is to convert the percentage of alloying elements other than carbon to the equivalent carbon percentage, because the iron-carbon phases are better understood than other iron-alloy phases. Most commonly this concept is used in welding, but it is also used when heat treating and casting cast iron. | 0 | Metallurgy |
DNA purification in 1869 by Dr. Friedrich Miescher’s, from salmon sperm and pus cells guided the scientists towards the presence of additional molecules in the cell except for proteins. Miescher identified the presence of a highly acidic molecule that he isolated from the pus cells and labeled it “nuclein”. The term was coined as the DNA isolated by Miescher was not protein and was derived from the nucleus of the cell. It wasn’t until 1944, when Oswald Avery proposed the DNA as a genetic carrier of information that the Miescher discovery was brought back to light.
Following the X-ray crystallography, by Rosalind Franklin and the determination of DNA double helix by Watson and Crick in 1953, further enhanced the understanding of DNA structure and allowed for the establishment of central dogma of molecular biology. However, one of the flaws with central dogma was the postulation that information flow proceeds from DNA to RNA to protein, which hinders the understanding of different regulatory mechanisms.
In 1955, George Palade identified the first ncRNA as a part of the large ribonucleoprotein complex (RNP). The second class of ncRNA to be discovered was transfer RNA (tRNA) in 1957. However, the first regulatory ncRNA was a microRNA discovered in 1988 from E.coli and was labeled as micF. On other hand, the first eukaryotic microRNA was discovered in C.elegans in 1993. It was derived from gene lin-4 and was identified as a small RNA molecule (as compared to longer mRNA molecules) forming stem-loop structures. This structure gets further modified to generate a shorter RNA that is complementary to the 3’UTR region of lin-14 transcript. This pathway allowed for a better understanding of different post translational gene silencing pathways. Since then, many other miRNAs have been discovered.
Detailed understanding of the mechanism behind this post translational silencing pathway was established in 2001 by Thomas Tuschl. It was discovered that the double stranded RNA gets processed into a shorter 25 nucleotides long fragment which is then modified into a short hairpin like structure by Drosha complex. The molecule is then diced by dicer enzymes into a functional double stranded RNA (dsRNA). These are then loaded onto the RISC complex which then finds and cleaves the targeted mRNA of interest in the cytoplasm.
It wasn’t until 1989 that the imprinting genes were discovered and the genome imprinting was established. The first two genomic imprinting genes were paternally expressed Igf2r and H19. These were both discovered independently in mice and were localized to chromosome 7. H19 is peculiar as it functions as a lncRNA but undergoes modifications similar to that of pre-mRNA processing such as splicing, 3’ polyadenylation and is transcribed by RNA polymerase II. This lncRNA plays a significant role in mice embryonic development and can be lethal if expressed during prenatal stages. More lncRNAs have been discovered in eukaryotes overtime. One such discovery that allowed for better understanding between H19 functions was a lncRNA called XIST (X inactive-specific transcript). | 1 | Gene expression + Signal Transduction |
A heat number is an identification coupon number that is stamped on a material plate after it is removed from the ladle and rolled at a steel mill.
Industry quality standards require materials to be tested at the manufacturer and the results of these tests be submitted through a report, also called a mill sheet, mill certificate or mill test certificate (MTC). The only way to trace a steel plate back to its mill sheet is the heat number. A heat number is similar to a lot number, which is used to identify production runs of any other product for quality control purposes. | 0 | Metallurgy |
Simmons was born on May 3, 1931. He attended Massachusetts Institute of Technology (MIT) in 1949. He became a metallurgist at the Allegheny Ludlum Steel corporation in Pittsburgh. He then worked for other steel companies before returning to become the chief executive of Allegheny, taking it public and then leading a management buyout. Having become wealthy, he then created a variety of endowments at MIT.
Simmons was also chairman of the Pittsburgh Symphony Orchestra between 1989 and 1997. He returned as chairman in 2003 until his retirement in 2015. | 0 | Metallurgy |
In Arabidopsis thaliana, there are three main families of transcription factors that contain B3 domain:
* ARF (Auxin Response Factors)
* ABI3 (ABscisic acid Insensitive3)
* RAV (Related to ABI3/VP1)
and are only known NMR solution phase structures of the B3 DNA Binding Domain. | 1 | Gene expression + Signal Transduction |
Pewter was first used around the beginning of the Bronze Age in the Near East. The earliest known piece of pewter was found in an Egyptian tomb, , but it is unlikely that this was the first use of the material. Pewter was used for decorative metal items and tableware in ancient times by the Egyptians and later the Romans, and came into extensive use in Europe from the Middle Ages until the various developments in pottery and glass-making during the 18th and 19th centuries. Pewter was the chief material for producing plates, cups, and bowls until the making of porcelain. Mass production of pottery, porcelain and glass products have almost universally replaced pewter in daily life, although pewter artifacts continue to be produced, mainly as decorative or specialty items. Pewter was also used around East Asia. Although some items still exist, Ancient Roman pewter is rare.
Lidless mugs and lidded tankards may be the most familiar pewter artifacts from the late 17th and 18th centuries, although the metal was also used for many other items including porringers (shallow bowls), plates, dishes, basins, spoons, measures, flagons, communion cups, teapots, sugar bowls, beer steins (tankards), and cream jugs. In the early 19th century, changes in fashion caused a decline in the use of pewter flatware. At the same time, production increased of both cast and spun pewter tea sets, whale-oil lamps, candlesticks, and so on. Later in the century, pewter alloys were often used as a base metal for silver-plated objects.
In the late 19th century, pewter came back into fashion with the revival of medieval objects for decoration. New replicas of medieval pewter objects were created, and collected for decoration. Today, pewter is used in decorative objects, mainly collectible statuettes and figurines, game figures, aircraft and other models, (replica) coins, pendants, plated jewellery and so on. Certain athletic contests, such as the United States Figure Skating Championships, award pewter medals to fourth-place finishers. | 0 | Metallurgy |
ScerTF is a comprehensive database of position weight matrices for the transcription factors of Saccharomyces. | 1 | Gene expression + Signal Transduction |
Calcineurin (CaN) is a calcium and calmodulin dependent serine/threonine protein phosphatase (also known as protein phosphatase 3, and calcium-dependent serine-threonine phosphatase). It activates the T cells of the immune system and can be blocked by drugs. Calcineurin activates nuclear factor of activated T cell cytoplasmic (NFATc), a transcription factor, by dephosphorylating it. The activated NFATc is then translocated into the nucleus, where it upregulates the expression of interleukin 2 (IL-2), which, in turn, stimulates the growth and differentiation of the T cell response. Calcineurin is the target of a class of drugs called calcineurin inhibitors, which include ciclosporin, voclosporin, pimecrolimus and tacrolimus. | 1 | Gene expression + Signal Transduction |
This technique is mostly used to produce coatings on structural materials. Such coatings provide protection against high temperatures (for example thermal barrier coatings for exhaust heat management), corrosion, erosion, wear; they can also change the appearance, electrical or tribological properties of the surface, replace worn material, etc. When sprayed on substrates of various shapes and removed, free-standing parts in the form of plates, tubes, shells, etc. can be produced. It can also be used for powder processing (spheroidization, homogenization, modification of chemistry, etc.). In this case, the substrate for deposition is absent and the particles solidify during flight or in a controlled environment (e.g., water). This technique with variation may also be used to create porous structures, suitable for bone ingrowth, as a coating for medical implants.
A polymer dispersion aerosol can be injected into the plasma discharge in order to create a grafting of this polymer on to a substrate surface. This application is mainly used to modify the surface chemistry of polymers. | 0 | Metallurgy |
The Newbery-Vautin chlorination process is a method for extracting gold from its ore through the use of chlorination. This process was jointly developed by James Cosmo Newbery and Claude Vautin. | 0 | Metallurgy |
MiRNA expression profiles are altered in psychiatric conditions, including depression, anxiety, and PTSD. It has been demonstrated that miR-324-5p expression is altered in the brains of suicide victims with depression and in the amygdala, the fear center of the brain, in PTSD. MiRNAs are an underexplored potential biomarker and target for treatment for psychiatric disease. | 1 | Gene expression + Signal Transduction |
Not much is known about archaeal termination. Euryarchaeal RNAPs seem to terminate on their own when poly-U stretches appear. | 1 | Gene expression + Signal Transduction |
As mentioned above, changes in MITF can result in serious health conditions. For example, mutations of MITF have been implicated in both Waardenburg syndrome and Tietz syndrome.
Waardenburg syndrome is a rare genetic disorder. Its symptoms include deafness, minor defects, and abnormalities in pigmentation. Mutations in the MITF gene have been found in certain patients with Waardenburg syndrome, type II. Mutations that change the amino acid sequence of that result in an abnormally small MITF are found. These mutations disrupt dimer formation, and as a result cause insufficient development of melanocytes. The shortage of melanocytes causes some of the characteristic features of Waardenburg syndrome.
Tietz syndrome, first described in 1923, is a congenital disorder often characterized by deafness and leucism. Tietz is caused by a mutation in the MITF gene. The mutation in MITF deletes or changes a single amino acid base pair specifically in the base motif region of the MITF protein. The new MITF protein is unable to bind to DNA and melanocyte development and subsequently melanin production is altered. A reduced number of melanocytes can lead to hearing loss, and decreased melanin production can account for the light skin and hair color that make Tietz syndrome so noticeable. | 1 | Gene expression + Signal Transduction |
Copper has earned a respected place in the related fields of architecture, building construction, and interior design. From cathedrals to castles and from homes to offices, copper is used for a variety of architectural elements, including roofs, flashings, gutters, downspouts, domes, spires, vaults, wall cladding, and building expansion joints.
The history of copper in architecture can be linked to its durability, corrosion resistance, prestigious appearance, and ability to form complex shapes. For centuries, craftsmen and designers utilized these attributes to build aesthetically pleasing and long-lasting building systems.
For the past quarter century, copper has been designed into a much wider range of buildings, incorporating new styles, varieties of colors, and different shapes and textures. Copper clad walls are a modern design element in both indoor and outdoor environments.
Some of the worlds most distinguished modern architects have relied on copper. Examples include Frank Lloyd Wright, who specified copper materials in all of his building projects; Michael Graves, an AIA Gold Medalist who designed over 350 buildings worldwide; Renzo Piano, who designed pre-patinated clad copper for the NEMO-Metropolis Museum of Science in Amsterdam; Malcolm Holzman, whose patinated copper shingles at the WCCO Television Communications Centre made the facility an architectural standout in Minneaoplis; and Marianne Dahlbäck and Göran Månsson, who designed the Vasa Museum, a prominent feature of Stockholms skyline, with copper cladding. Architect Frank O. Gehry's enormous copper fish sculpture atop the Vila Olimpica in Barcelona is an example of the artistic use of copper.
Coppers most noteworthy aesthetic trait is its range of hues, from a bright metallic colour to iridescent brown to near black and, finally, to a greenish verdigris patina. Architects describe the array of browns as russet, chocolate, plum, mahogany, and ebony. The metals distinctive green patina has long been coveted by architects and designers.
This article describes practical and aesthetic benefits of copper in architecture as well as its use in exterior applications, interior design elements, and green buildings. | 0 | Metallurgy |
As the slag becomes enriched with iron oxide during the reaction in air, it becomes basic and then combines with the siliceous refractory lining, which is very acidic. A basic refractory lining would not react and would therefore lower the cost of production. The adoption of a lining inspired by one developed by Sidney Thomas and Percy Gilchrist in 1877 was suggested by Hollway during his last tests in the early 1800s. However, the idea was not tested, as fundamental problems related to the air blowing were more of a problem than refractory optimization.
In 1890, a basic refractory lining was tested on one of Parrot Smelter's Manhès-David converters, in Butte, under the direction of Herman A. Keller. The tests did not result in a lining compatible with industrial operation. In 1906, Ralph Baggaley, still in Montana, succeeded, after a number of tests, in industrializing a basic coating at Pittsmont Smelter, which was abandoned in 1908 after he left the factory. After all that, the Norwegian Kudsen succeeded as of 1908 in using a basic coating with the Sulitjelma Mines. He carried out two successive blowings there, initially in a small converter with a basic coating, and then in a second traditional converter with an acidic coating.
Finally, in 1909, at the Baltimore Copper Company's Smelter, the Americans William H. Peirce and Elias A.C. Smith succeeded in addressing the main drawbacks of basic refractories; basic refractories were more fragile, and, above all, they dissipated more heat than acidic refractories. By developing a masonry suitable for the cylindrical converter and increasing the amount of metal fed into the furnace, they solved the remaining problems.
Peirce and Smith's converter proved much more advantageous than that of Manhès and David. The basic refractory, which did not react with slag, lasted much longer. This improvement eliminated the need for replacement of the converters, the construction of masonry installations, and replacement converters (there were two masonry converters for every one in service in 1897 at Anaconda Copper). It also reduced the risk of piercings due to poor control of wearing of the refractory. The refractory layer could then be thinner, increasing the capacity of the converter. The capacity was not dependent on wearing of the refractory, thus simplifying the management of the flows of molten metal in factories.
If the material used to prepare the acid refractory contains copper, or even silver or gold (frequently associated with copper in gold-bearing quartz), these metals join the matte as the lining is removed. Considering the refractory's rapid destruction, the economic advantage of an acidic refractory is therefore only realized if its consumption adds value to the process. This situation is however rather rare and, even if this is the case, silica rich in precious metals can be made by other economically viable means. Therefore, in 1921, the basic refractory was considered the main factor in the cost reduction in the extraction of copper ores. In some cases, a reduction in conversion costs from $15–20 to $4–5 was reported. | 0 | Metallurgy |
The word transcriptome is a portmanteau of the words transcript and genome. It appeared along with other neologisms formed using the suffixes -ome and -omics to denote all studies conducted on a genome-wide scale in the fields of life sciences and technology. As such, transcriptome and transcriptomics were one of the first words to emerge along with genome and proteome. The first study to present a case of a collection of a cDNA library for silk moth mRNA was published in 1979. The first seminal study to mention and investigate the transcriptome of an organism was published in 1997 and it described 60,633 transcripts expressed in S. cerevisiae using serial analysis of gene expression (SAGE). With the rise of high-throughput technologies and bioinformatics and the subsequent increased computational power, it became increasingly efficient and easy to characterize and analyze enormous amount of data. Attempts to characterize the transcriptome became more prominent with the advent of automated DNA sequencing during the 1980s. During the 1990s, expressed sequence tag sequencing was used to identify genes and their fragments. This was followed by techniques such as serial analysis of gene expression (SAGE), cap analysis of gene expression (CAGE), and massively parallel signature sequencing (MPSS). | 1 | Gene expression + Signal Transduction |
More than 100 immune system disorders affect humans, including inflammatory bowel diseases, multiple sclerosis, systemic lupus erythematosus, bloom syndrome, familial cold autoinflammatory syndrome, and dyskeratosis congenita. The Shapiro–Senapathy algorithm has been used to discover genes and mutations involved in many immune disorder diseases, including Ataxia telangiectasia, B-cell defects, epidermolysis bullosa, and X-linked agammaglobulinemia.
Xeroderma pigmentosum, an autosomal recessive disorder is caused by faulty proteins formed due to new preferred splice donor site identified using S&S algorithm and resulted in defective nucleotide excision repair.
Type I Bartter syndrome (BS) is caused by mutations in the gene SLC12A1. S&S algorithm helped in disclosing the presence of two novel heterozygous mutations c.724 + 4A > G in intron 5 and c.2095delG in intron 16 leading to complete exon 5 skipping.
Mutations in the MYH gene, which is responsible for removing the oxidatively damaged DNA lesion are cancer-susceptible in the individuals. The IVS1+5C plays a causative role in the activation of a cryptic splice donor site and the alternative splicing in intron 1, S&S algorithm shows, guanine (G) at the position of IVS+5 is well conserved (at the frequency of 84%) among primates. This also supported the fact that the G/C SNP in the conserved splice junction of the MYH gene causes the alternative splicing of intron 1 of the β type transcript.
Splice site scores were calculated according to S&S to find EBV infection in X-linked lymphoproliferative disease. Identification of Familial tumoral calcinosis (FTC) is an autosomal recessive disorder characterized by ectopic calcifications and elevated serum phosphate levels and it is because of aberrant splicing. | 1 | Gene expression + Signal Transduction |
CTCF physically binds to itself to form homodimers,
which causes the bound DNA to form loops. CTCF also occurs frequently at the boundaries of sections of DNA bound to the nuclear lamina. Using chromatin immuno-precipitation (ChIP) followed by ChIP-seq, it was found that CTCF localizes with cohesin genome-wide and affects gene regulatory mechanisms and the higher-order chromatin structure. It is currently believed that the DNA loops are formed by the "loop extrusion" mechanism, whereby the cohesin ring is actively being translocated along the DNA until it meets CTCF. CTCF has to be in a proper orientation to stop cohesin. | 1 | Gene expression + Signal Transduction |
Platinum-samarium forms crystals of rhombic crystal system, space group P nma, cell parameters a = 0.7148 nm, b = 0.4501 nm, c = 0.5638 nm, Z = 4, structure similar to that of iron boride (FeB).
The compound melts congruently at a temperature of ≈1810 °C. | 0 | Metallurgy |
In this part of the experiment, Tamm et al. transfected 293 cells with survivin and lysed them to obtain cell lysate. The lysates were incubated with different caspase forms and survivin was immunopercipitated with anti-survivin antibody. The idea behind this is that, if survivin binds physically with the caspase it is incubated with, it will be co-precipitated along with the survivin while everything else in the lysate is washed away. The immunoprecipitates were then run on SDS-PAGE and then immunoblotted for detection of the desired caspase. If the caspase of interest was detected, it meant that it was bound to survivin in the immunoprecipitation step implicating that survivin and the particular caspase had bound beforehand. Active caspase-3 and -7 coimmunoprecipitated with survivin. The inactive proforms of caspase-3 and -7 did not bind survivin. Survivin also does not bind to active caspase-8. Caspase-3 and -7 are effector proteases whereas caspase-8 is an initiator caspase that sits more upstream in the apoptotic pathway. These results demonstrate survivins capability to bind with particular caspases in vitro, but may not necessarily translate over to actual physiological conditions. Later, a 2001 study confirmed that human survivin tightly binds caspase-3 and -7 when expressed in E. coli'.
Further evidence to support the idea that survivin blocks apoptosis by directly inhibiting caspases was given by Tamm et al. 293 cells were transfected with either overexposed caspase-3 or -7 encoding plasmid and with survivin. They showed that survivin inhibited processing of these two caspases into their active forms. While survivin has been shown as mentioned above to bind to only the active forms of these caspases, it is likely here that survivin inhibits the active forms of the caspases resulting from cleaving and activating more of its own proforms. Thus, survivin acts possibly by preventing such a cascade of cleavage and activation amplification from happening resulting in decreased apoptosis.
In similar manner, looking at the mitochondrial pathway of apoptosis, cytochrome c was transiently expressed in 293 cells to look at the inhibitory effects survivin had on this pathway. Although the details are not here, survivin was shown to also inhibit cytochrome c and caspase-8-induced activation of caspases. | 1 | Gene expression + Signal Transduction |
Johnson Matthey Technology Review, known as Platinum Metals Review before 2014, is a quarterly, peer-reviewed scientific journal publishing reports on scientific research on the platinum group metals and related industrial developments. | 0 | Metallurgy |
TiAl has the lowest density of 3.4 g/cm, the highest micro hardness of 465–670 kg/mm and the best oxidation resistance even at 1 000 °C. However, the applications of TiAl in the engineering and aerospace fields are limited by its poor ductility. In addition, the loss of ductility at ambient temperature is usually accompanied by a change of fracture mode from ductile transgranular to brittle intergranular or to brittle cleavage. Despite the fact that a lot of toughening strategies have been developed to improve their toughness, machining quality is still a difficult problem to tackle. Near-net shape manufacturing technology is considered as one of the best choices for preparing such materials. {date=July 2022} | 0 | Metallurgy |
The specific feature of German silver overlay is the degree of purity – 925 for Sterling silver or 999 for fine silver. The quality of silver used for German overlay can be seen by identifying the impressed 1000 mark (usually on the base or side of an item). The purity and thickness of the silver overlay ensures the beauty of the item is maintained without any loss to the silver even after many years of cleaning. Although other kinds of silver, such as nickel silver, can be sued for silver overlay, the effect is not as vibrant.
Bohemian and Venetian Murano glass are often described as silver overlay, but the silver is so thin that it looks as though it has been painted onto the surface, producing a flat effect.
Friedrich Deusch invented a way to combine silver and a non-conductive surface such as porcelain or glass with galvanization. He achieved this with a special conductive fluid (a type of flux) which was fixed permanently on the prepared form. The particular objects (such as a vase) were first roughened by engraving or using hydrofluoric acid to etch a design. This implies that a very exact covering of the surfaces had to be achieved to prevent any damage to areas which were not to be overlaid. Maybe they used a masking lacquer which could withstand the following baking in the kiln which was used to fuse the flux with the surface of the item. The next step was to galvanize the item with the purest silver (1000).
It was very important to monitor items being overlaid with silver – waiting too long resulted in visible dark spots and slight roughness where the cathode or anode were fixed. The cathode and anode were used to charge the item electronically and this allowed the fusion of silver to the area painted with the silver flux. The thickness of silver desired on the finished item determined how long the item needed to be left in the silver bath; this could be more than 30 hours. Finally, if the masking lacquer (discussed earlier) did not burn in the kiln, it must have been removed later (probably with chemical fluids).
When colored enamels were to be used on the finished product, they had to be fired prior to the final stage of the silver overlay process. Engraving the silver was the last, and sometimes most laborious, work; it was brought to the highest level by Friedrich Wilhelm Spahr and his workers. | 0 | Metallurgy |
The deformation field at the slip-band is due to three-dimensional elastic and plastic strains where the concentrated shear of the slip band tip deforms the grain in its vicinity. The elastic strains describe the stress concentration ahead of the slip band, which is important as it can affect the transfer of plastic deformation across grain boundaries. An understanding of this is needed to support the study of yield and inter/intra-granular fracture. The concentrated shear of slip bands can also nucleate cracks in the plane of the slip band, and persistent slip bands that lead to intragranular fatigue crack initiation and growth may also form under cyclic loading conditions. To properly characterise slip bands and validate mechanistic models for their interactions with microstructure, it is crucial to quantify the local deformation fields associated with their propagation. However, little attention has been given to slip bands within grains (i.e., in the absence of grain boundary interaction).
The long-range stress field (i.e., the elastic strain field) around the tip of a stress concentrator, such as a slip band, can be considered a singularity equivalent to that of a crack. This singularity can be quantified using a path independent integral since it satisfies the conservation laws of elasticity. The conservation laws of elasticity related to translational, rotational, and scaling symmetries were derived initially by Knowles and Sternberg from the Noether's theorem. Budiansky and Rice introduced the J-, M-, L-integral and were the first to give them a physical interpretation as the strain energy-release rates for mechanisms such as cavity propagation, simultaneous uniform expansion, and defect rotation, respectively. When evaluated over a surface that encloses a defect, these conservation integrals represent a configurational force on the defect. That work paved the way for the field of Configurational mechanics of materials, with the path-independent J-integral now widely used to analyse the configurational forces in problems as diverse as dislocation dynamics, misfitting inclusions, propagation of cracks, shear deformation of clays, and co-planar dislocation nucleation from shear loaded cracks. The integrals have been applied to linear elastic and elastic-plastic materials and have been coupled with processes such as thermal and electrochemical loading, and internal tractions. Recently, experimental fracture mechanics studies have used full-field in situ measurements of displacements and elastic strains to evaluate the local deformation field surrounding the crack tip as a J-integral.
Slip bands form due to plastic deformation, and the analysis of the force on a dislocation considers the two-dimensional nature of the dislocation line defect. General definitions of the Peach–Koehler configurational force (𝑃) (or the elastic energy-momentum tensor ) on a dislocation in the arbitrary 𝑥, 𝑥, 𝑥 coordinate system, decompose the Burgers vector (𝑏) to orthogonal components. This leads to the generalised definition of the J-integral in equations below. For a dislocation pile-up, the J-integral is the summation of the Peach–Koehler configurational force of the dislocations in the pile-up (including out-of-plane, 𝑏 ).
𝐽 = ∫ 𝑃 𝑛 𝑑𝑆 = ∫(𝑊 𝑛− 𝑇 𝑢) 𝑑𝑆
𝐽 = 𝑅 𝐽, 𝑖,𝑗,𝑘=1,2,3
where 𝑆 is an arbitrary contour around the dislocation pile-up with unit outward normal 𝑛, 𝑊 is the strain energy density, 𝑇 = 𝜎 𝑛 is the traction on 𝑑𝑆, 𝑢 are the displacement vector components, 𝐽 is 𝐽-integral evaluated along the 𝑥 direction, and 𝑅 is a second-order mapping tensor that maps 𝐽 into 𝑥 direction. This vectorial 𝐽-integral leads to numerical difficulties in the analysis since 𝐽 and, for a three-dimensional slip band or inclined crack, the 𝐽 terms cannot be neglected. | 0 | Metallurgy |
Follicle-stimulating hormone (FSH) is an agonist of the FSHR.
Small-molecule positive allosteric modulators of the FSHR have been developed. | 1 | Gene expression + Signal Transduction |
The Centre for Gene Regulation and Expression, located within the School of Life Sciences, University of Dundee, is a research facility working in the field of gene expression and chromosome biology. Previously part of the Dundee Biocentre and receiving significant Wellcome Trust funding from 1995 onwards, it was awarded Wellcome Trust Centre status in 2008. Professor Tom Owen-Hughes is the centre's director.
The centre aims to enhance our understanding of how genes are regulated at both the single cell and whole organism level. Researchers use a wide range of advanced techniques, including live cell fluorescent imaging and mass spectrometry-based proteomics, to explore the functions of key proteins and molecular mechanisms in cell biology. | 1 | Gene expression + Signal Transduction |
Between 100 million and 280 million tons of phosphogypsum waste are estimated to be produced annually as a consequence of the processing of phosphate rock for the production of phosphate fertilizers. In addition to being useless and abundant, phosphogypsum is radioactive due to the presence of naturally occurring uranium and thorium, and their daughter isotopes. Depending on the price achievable on the uranium market, extraction of the uranium content may be economically lucrative even absent other incentives, such as reducing the harm the radioactive heavy metals do to the environment. | 0 | Metallurgy |
In materials science, environmental stress fracture or environment assisted fracture is the generic name given to premature failure under the influence of tensile stresses and harmful environments of materials such as metals and alloys, composites, plastics and ceramics.
Metals and alloys exhibit phenomena such as stress corrosion cracking, hydrogen embrittlement, liquid metal embrittlement and corrosion fatigue all coming under this category. Environments such as moist air, sea water and corrosive liquids and gases cause environmental stress fracture. Metal matrix composites are also susceptible to many of these processes.
Plastics and plastic-based composites may suffer swelling, debonding and loss of strength when exposed to organic fluids and other corrosive environments, such as acids and alkalies. Under the influence of stress and environment, many structural materials, particularly the high-specific strength ones become brittle and lose their resistance to fracture. While their fracture toughness remains unaltered, their threshold stress intensity factor for crack propagation may be considerably lowered. Consequently, they become prone to premature fracture because of sub-critical crack growth. This article aims to give a brief overview of the various degradation processes mentioned above. | 0 | Metallurgy |
Copper roofs are extremely durable in most environments. They have performed well for over 700 years, primarily because of the protective patina that forms on copper surfaces. Tests conducted on 18th Century copper roofs in Europe showed that, in theory, they could last for one thousand years. | 0 | Metallurgy |
The STAT3-Ser/Hes3 signaling axis is a specific type of intracellular signaling pathway that regulates several fundamental properties of cells. | 1 | Gene expression + Signal Transduction |
DSIF plays the same role for HIV-1 gene expression as it would normally in transcription. This is because P-TEFb phosphorylates DSIF the same regardless of whether or not P-TEFb goes through normal cellular regulation or bypasses it due to Tat. | 1 | Gene expression + Signal Transduction |
The Egyptians were practicing cire perdue from the mid 3rd millennium BC, shown by Early Dynastic bracelets and gold jewellery. Inserted spouts for ewers (copper water vessels) from the Fourth Dynasty (Old Kingdom) were made by the lost-wax method. Hollow castings, such as the Louvre statuette from the Fayum find appeared during the Middle Kingdom, followed by solid cast statuettes (like the squatting, nursing mother, in Brooklyn) of the Second Intermediate/Early New Kingdom. The hollow casting of statues is represented in the New Kingdom by the kneeling statue of Tuthmosis IV (British Museum, London) and the head fragment of Ramesses V (Fitzwilliam Museum, Cambridge). Hollow castings become more detailed and continue into the Eighteenth Dynasty, shown by the black bronze kneeling figure of Tutankhamun (Museum of the University of Pennsylvania). Cire Perdue is used in mass-production during the Late Period to Graeco-Roman times when figures of deities were cast for personal devotion and votive temple offerings. Nude female-shaped handles on bronze mirrors were cast by the lost-wax process. | 0 | Metallurgy |
The Cape York meteorite, also known as the Innaanganeq meteorite, is one of the largest known iron meteorites, classified as a medium octahedrite in chemical group IIIAB. In addition to many small fragments, at least eight large fragments with a total mass of 58 tonnes have been recovered, the largest weighing . The meteorite is named after the location where the largest fragment was found: east of Cape York, in Savissivik, Meteorite Island, Greenland.
The date of the meteorite fall is debated, but was likely within the last few thousand years. It was known to the Inughuit (the local Inuit) for centuries, who used it as a source of meteoritic iron for tools. The first foreigner to reach the meteorite was Robert Peary in 1894, with the assistance of Inuit guides. Large pieces are on display at the American Museum of Natural History and the University of Copenhagen Geological Museum. | 0 | Metallurgy |
Tumor development is a complex process that requires cell division, growth, and survival. One approach used by tumors to upregulate growth and survival is through autocrine production of growth and survival factors. Autocrine signaling plays critical roles in cancer activation and also in providing self-sustaining growth signals to tumors. | 1 | Gene expression + Signal Transduction |
In 1969, Pinewood film studios hired a chemistry laboratory at Fulmer for use as a film set for the film "The Chairman" (also known as "The Most Dangerous Man in the World"), starring Gregory Peck. | 0 | Metallurgy |
Fulmer grew steadily so that by 1960 there were about 100 staff. Individual research investigators were often recruited to work on specific projects as contracts were obtained. Each recruit was also expected to develop proposals for work in his or her areas of expertise, whether or not these fitted into Fulmers existing pattern of work. This system resulted in a progressive evolution and wide diversification of Fulmers skills base. This was a strength in that faced with a materials problem Fulmer could usually help the client with new perspectives. | 0 | Metallurgy |
The gene for the FSHR is found on chromosome 2 p21 in humans. The gene sequence of the FSHR consists of about 2,080 nucleotides. | 1 | Gene expression + Signal Transduction |
In metallurgical processes tank leaching is a hydrometallurgical method of extracting valuable material (usually metals) from ore. | 0 | Metallurgy |
The YenR and YenI proteins produced by the gammaproteobacterium Yersinia enterocolitica are similar to Aliivibrio fischeri LuxR and LuxI. YenR activates the expression of a small non-coding RNA, YenS. YenS inhibits YenI expression and acylhomoserine lactone production. YenR/YenI/YenS are involved in the control of swimming and swarming motility. | 1 | Gene expression + Signal Transduction |
Much of the work done by the BNF during the 1939–45 period was of vital use for the defence industry. This especially included solving many of the corrosion problems of seawater cooled condenser tubes and tube plates that had resulted in many ships being unserviceable and significant improvements in corrosion resistant alloys for seawater pumps and pipe fittings. No work was ever carried out on active materials for nuclear weapons. Some consultancy work was undertaken on paperwork for new designs.
There has been much publicity about Melita Norwood (née Sirnis) who joined the BNF in 1932 as a clerk, was eventually promoted to secretary and retired 1972. As secretary to a Research Superintendent she had access to the papers prepared at the BNF for presentation to the research committees and some contractors. Some of these she chose to copy to Russian intelligence. This information was made use of by them and did occasionally result in one of their research organisations publishing development work on non-ferrous metals similar to and sooner than the BNF in Britain. | 0 | Metallurgy |
The applications of chemotactic drug delivery systems include but are not limited to cancer therapy, wound healing, and inflammation. The ability to target specific cells and locations within the body through chemical cues has opened up new avenues for the field of drug delivery, allowing for increased drug efficacy and reducing harmful side effects. | 1 | Gene expression + Signal Transduction |
The recrystallization behavior of materials containing a wide distribution of particle sizes can be difficult to predict. This is compounded in alloys where the particles are thermally-unstable and may grow or dissolve with time. In various systems, abnormal grain growth may occur giving rise to unusually large crystallites growing at the expense of smaller ones. The situation is more simple in bimodal alloys which have two distinct particle populations. An example is Al-Si alloys where it has been shown that even in the presence of very large (<5 μm) particles the recrystallization behavior is dominated by the small particles (Chan & Humphreys 1984). In such cases the resulting microstructure tends to resemble one from an alloy with only small particles. | 0 | Metallurgy |
A pyrometer, or radiation thermometer, is a type of remote sensing thermometer used to measure the temperature of distant objects. Various forms of pyrometers have historically existed. In the modern usage, it is a device that from a distance determines the temperature of a surface from the amount of the thermal radiation it emits, a process known as pyrometry, a type of radiometry.
The word pyrometer comes from the Greek word for fire, "πῦρ" (pyr), and meter, meaning to measure. The word pyrometer was originally coined to denote a device capable of measuring the temperature of an object by its incandescence, visible light emitted by a body which is at least red-hot. Infrared thermometers, can also measure the temperature of cooler objects, down to room temperature, by detecting their infrared radiation flux. Modern pyrometers are available for a wide range of wavelengths and are generally called radiation thermometers. | 0 | Metallurgy |
Chloride inclusions (MgCl, NaCl, CaCl, …) are a special type of inclusion as they are liquid in liquid metal. When aluminium solidifies, they form spherical voids similar to hydrogen gas porosity but the void contains a chloride crystal formed when aluminium became colder. | 0 | Metallurgy |
Sigma-2 receptors have been associated with pancreatic cancer, lung cancer, breast cancer, melanoma, prostate cancer, and ovarian cancer. Tumor cells are shown to over-express sigma-2 receptors, allowing for potential cancer therapies as many sigma-2 receptor mediated cell responses happen only in tumor cells. Tumor cell responses are modulated via ligand binding. Sigma receptor ligands can act as agonists or antagonists, generating different cellular responses. Agonists inhibit tumor cell proliferation and induce apoptosis, which is thought to be triggered by caspase-3 activity. Antagonists promote tumor cell proliferation, but this mechanism is less understood. Sigma receptor ligands have been conjugated to nanoparticles and peptides to deliver cancer treatment to tumor cells without targeting other tissues. The success with these methods have been limited to in vitro trials. Additionally, using sigma-2 receptors to target tumor cells allows for synergizing anti-cancer drug therapies. Some studies have shown that certain sigma receptor inhibitors increase cancer cells' susceptibility to chemotherapy. Other types of binding to sigma-2 receptors increases cytotoxicity of doxorubicin, antinomyocin, and other cancer cell killing drugs. | 1 | Gene expression + Signal Transduction |
In the field of molecular biology, the ETS (E26 transformation-specific or E-twenty-six. (Erythroblast Transformation Specific)) family is one of the largest families of transcription factors and is unique to animals. There are 29 genes in humans, 28 in the mouse, 10 in Caenorhabditis elegans and 9 in Drosophila. The founding member of this family was identified as a gene transduced by the leukemia virus, E26. The members of the family have been implicated in the development of different tissues as well as cancer progression. | 1 | Gene expression + Signal Transduction |
* O. K. Berdiev
* I. N. Khlopin
* Boris Kuftin
* Gorislava Nikolaevna Lisit︠s︡yna
* Mikhail Evgenievich Masson
* Vadim Mikhailovich Masson
* G. E. Markov
* Alexey Okladnikov
* Viktor Sarianidi | 0 | Metallurgy |
The sclerometer, also known as the Turner-sclerometer (from meaning "hard"), is an instrument used by metallurgists, material scientists and mineralogists to measure the scratch hardness of materials. It was invented in 1896 by Thomas Turner (1861–1951), the first Professor of metallurgy in Britain, at the University of Birmingham.
The Turner-Sclerometer test consists of measuring the amount of load required to make a scratch.
In test a weighted diamond point is drawn, once forward and once backward, over the smooth surface of the material to be tested. The hardness number is the weight in grams required to produce a standard scratch. The scratch selected is one which is just visible to the naked eye as a dark line on a bright reflecting surface. It is also the scratch which can just be felt with the edge of a quill when the latter is drawn over the smooth surface at right angles to a series of such scratches produced by regularly increasing weights. | 0 | Metallurgy |
Through the recent study of untranslated regions, general information has been gathered about the nature and function of these elements. However, there is still much that is unknown about these regions of mRNA. Since the regulation of gene expression is critical in the proper function of cells, this is an area of study that needs to be investigated further. It is important to consider that mutations in 3' untranslated regions have the potential to alter the expression of several genes that may appear unrelated. We are only beginning to understand the links between proper untranslated region function, and disease states of cells. | 1 | Gene expression + Signal Transduction |
Devices made from aluminum and its alloys, such as aircraft, must be carefully designed to minimize or evenly distribute flexure, which can lead to work hardening and, in turn, stress cracking, possibly causing catastrophic failure. For this reason modern aluminum aircraft will have an imposed working lifetime (dependent upon the type of loads encountered), after which the aircraft must be retired. | 0 | Metallurgy |
NbSn was discovered to be a superconductor in 1954, one year after the discovery of VSi, the first example of an AB superconductor. In 1961 it was discovered that niobium–tin still exhibits superconductivity at large currents and strong magnetic fields, thus becoming the first known material to support the high currents and fields necessary for making useful high-power magnets and electric power machinery. | 0 | Metallurgy |
CKLF-like MARVEL transmembrane domain-containing protein 3 (i.e. CMTM3), also termed chemokine-like factor superfamily 3 (i.e. CKLFSF3), is a member of the CKLF-like MARVEL transmembrane domain-containing family (i.e. CMTM) of proteins. In humans, CMTM2 protein is encoded by the CMTM3 gene located in band 22.1 on the long (i.e. "q") arm of chromosome 16. This protein is expressed in a wide range of tissues, including fetal tissues. It is highly expressed in the male reproductive system, particularly testicular tissues and may play a role in the development of this tissue. It is also highly expressed in the immune system including circulating blood cells, i.e. B lymphocytes, CD4+ T lymphocytes, and monocytes. However, CMTM3 protein is weakly expressed or unexpressed in the malignant tissues of several types of cancers. In many but not all of theses cancers, this decreased or lack of expression appears due to methylation of the GpC islands in the promoter region, and thereby the silencing, of the CMTM3 gene.
Studies of CMTM3 protein levels in normal versus malignant tissues found that the malignant tissue levels of several types of cancer were lower, in a variable percentage of cases, than the levels in the normal tissues as well as the cases with high CMTM2 levels in the same cancer type. These cancers included those of the stomach, breast, nasopharynx (e.g. oral squamous cell carcinoma), male larynx, esophagus, prostate gland, colon, and kidney (i.e. the kidney clear-cell type). Moreover, low cancer tissue levels of CTMT3 protein were found to be associated with poorer prognoses compared to cases with higher levels of this protein in cancers of the stomach, esophagus, nasopharynx (i.e. oral squamous cell carcinoma type), and prostate gland. These finding suggest that the CMTM3 protein may act to suppress the development and/or progression of these cancers. Further studies are needed to support this suggestion and determine if CMTM3 protein can be a useful clinical marker to predict the severity of these cancers and/or serve as a therapeutic target for treating them.
Contrastingly, other studies have reported that: 1) CMTM3 protein promoted the proliferation of cultured glioblastoma immortalized cells; 2) high levels of CMTM3 protein were associated with shorter survival times in individuals with glioblastomas and gastric cancer; 3) analyses of 178 patients with pancreatic cancer found that their tumor tissues had higher CMTM3 protein levels than normal nearby pancreas tissues; and 4) patients with high levels of CMTM3 protein in their pancreatic cancer tissues had poorer prognoses and overall survival rates compared to patients with lower CMTM3 levels in their pancreatic cancer tissues. These findings suggest that CMTM3 acts to promote the development and/or progression of these three cancer types. They support further studies to confirm this suggestion, to determine if CMTM3 can be use as a prognostic indicator and a clinical therapeutic target for these three cancer types. Further investigations into the mechanisms behind the apparent ability of CMTM3 to suppress or promote these cancers are also needed. | 1 | Gene expression + Signal Transduction |
G-protein-coupled receptor oligomerisation is a widespread phenomenon. One of the best-studied examples is the metabotropic GABA receptor. This so-called constitutive receptor is formed by heterodimerization of GABAR1 and GABAR2 subunits. Expression of the GABAR1 without the GABAR2 in heterologous systems leads to retention of the subunit in the endoplasmic reticulum. Expression of the GABAR2 subunit alone, meanwhile, leads to surface expression of the subunit, although with no functional activity (i.e., the receptor does not bind agonist and cannot initiate a response following exposure to agonist). Expression of the two subunits together leads to plasma membrane expression of functional receptor. It has been shown that GABAR2 binding to GABAR1 causes masking of a retention signal of functional receptors. | 1 | Gene expression + Signal Transduction |
There are three types of shrinkage: shrinkage of the liquid, solidification shrinkage and patternmakers shrinkage. The shrinkage of the liquid is rarely a problem because more material is flowing into the mold behind it. Solidification shrinkage occurs because metals are less dense as a liquid than a solid, so during solidification the metal density dramatically increases. Patternmakers shrinkage refers to the shrinkage that occurs when the material is cooled from the solidification temperature to room temperature, which occurs due to thermal contraction. | 0 | Metallurgy |
Various techniques are available for strengthening concrete structures, to increase the load-carrying capacity or else to improve the in-service performance. These include increasing the concrete cross-section and adding material such as steel plate or fiber composites to enhance the tensile capacity or increase the confinement of the concrete for improved compression capacity. | 0 | Metallurgy |
The terms resin flux and rosin flux are ambiguous and somewhat interchangeable, with different vendors using different assignments. Generally, fluxes are labeled as rosin if the vehicle they are based on is primarily natural rosin. Some manufactures reserve "rosin" designation for military fluxes based on rosin (R, RMA and RA compositions) and label others as "resin".
Rosin has good flux properties. A mixture of organic acids (resin acids, predominantly abietic acid, with pimaric acid, isopimaric acid, neoabietic acid, dihydroabietic acid, and dehydroabietic acid), rosin is a glassy solid, virtually nonreactive and noncorrosive at normal temperature, but liquid, ionic and mildly reactive to metal oxides at molten state. Rosin tends to soften between 60–70 °C and is fully fluid at around 120 °C; molten rosin is weakly acidic and is able to dissolve thinner layers of surface oxides from copper without further additives. For heavier surface contamination or improved process speed, additional activators can be added.
There are several possible activator groups for rosins:
* halide activators (organic halide salts, e.g. dimethylammonium chloride and diethylammonium chloride)
* organic acids (monocarboxylic, e.g. formic acid, acetic acid, propionic acid, and dicarboxylic, e.g. oxalic acid, malonic acid, sebacic acid)
There are three types of rosin: gum rosin (from pine tree oleoresin), wood rosin (obtained by extraction of tree stumps), and tall oil rosin (obtained from tall oil, a byproduct of kraft paper process). Gum rosin has a milder odor and lower tendency to crystallize from solutions than wood rosin, and is therefore preferred for flux applications. Tall oil rosin finds increased use due to its higher thermal stability and therefore lower tendency to form insoluble thermal decomposition residues. The composition and quality of rosin differs by the tree type, and also by location and even by year. In Europe, rosin for fluxes is usually obtained from a specific type of Portuguese pine; in America a North Carolina variant is used.
Natural rosin can be used as is, or can be chemically modified by e.g. esterification, polymerization, or hydrogenation. The properties being altered are increased thermal stability, better cleanability, altered solution viscosity, and harder residue (or conversely, softer and more tacky residue). Rosin can be also converted to a water-soluble rosin flux, by formation of an ethoxylated rosin amine, an adduct with a polyglycol and an amine.
One of the early fluxes was a mixture of equal amounts of rosin and vaseline. A more aggressive early composition was a mixture of saturated solution of zinc chloride, alcohol, and glycerol.
Fluxes can be also prepared from synthetic resins, often based on esters of polyols and fatty acids. Such resins have improved fume odor and lower residue tack, but their fluxing activity and solubility tend to be lower than that of natural resins. | 0 | Metallurgy |
Bronze technology was imported to China from the steppes. The oldest bronze object found in China was a knife found at a Majiayao culture site in Dongxiang, Gansu, and dated to 2900–2740 BC. Further copper and bronze objects have been found at Machang-period sites in Gansu. Metallurgy spread to the middle and lower Yellow River region in the late 3rd millennium BC. Contacts between the Afanasievo culture and the Majiayao culture and the Qijia culture have been considered for the transmission of bronze technology. From around 2000 BCE, cast bronze objects such as the socketed spear with single side hook were imported and adapted from the Seima-Turbino culture.
The Erlitou culture (c. 1900 – 1500 BCE), Shang Dynasty (c. 1600 – 1046 BCE) and Sanxingdui culture (c. 1250 – 1046 BCE) of early China used bronze vessels for rituals (see Chinese ritual bronzes) as well as farming implements and weapons. By 1500 BCE, excellent bronzes were being made in China in large quantities, partly as a display of status, and as many as 200 large pieces were buried with their owner for use in the afterlife, as in the Tomb of Fu Hao, a Shang queen.
In the tomb of the first Qin Emperor and multiple Warring States period tombs, extremely sharp swords and other weapons were found, coated with chromium oxide, which made the weapons rust resistant. The layer of chromium oxide used on these swords was 10 to 15 micrometers and left them in pristine condition to this day. Chromium was first scientifically attested in the 18th century.
The beginning of new breakthroughs in metallurgy occurred towards the Yangzi Rivers south in Chinas southeastern region in the Warring States Period such as gilt-bronze swords. | 0 | Metallurgy |
An old-standing topic in grain growth is the evolution of the grains size distribution. Inspired by the work of Lifshitz and Slyozov on Ostwald ripening, Hillert has suggested that in a normal grain growth process the size distribution function must converge to a self-similar solution, i.e. it becomes invariant when the grain size is scaled with a characteristic length of the system that is proportional to the average grain size .
Several simulation studies, however, have shown that the size distribution deviates from the Hillerts self-similar solution. Hence a search for a new possible self-similar solution was initiated that indeed led to a new class of self-similar distribution functions. Large-scale phase field simulations have shown that there is indeed a self-similar behavior possible within the new distribution functions. It was shown that the origin of the deviation from Hillerts distribution is indeed the geometry of grains specially when they are shrinking. | 0 | Metallurgy |
piRNAs represent the largest class of small non-coding RNA molecules expressed in animal cells, deriving from a large variety of sources, including repetitive DNA and transposons. However, the biogenesis of piRNAs is also the least well understood. piRNAs appear to act both at the post-transcriptional and chromatin levels. They are distinct from miRNA due to at least an increase in terms of size and complexity. Repeat associated small interfering RNA (rasiRNAs) are considered to be a subspecies of piRNA. | 1 | Gene expression + Signal Transduction |
Corrosion engineers and consultants tend to specialize in Internal or External corrosion scenarios. In both, they may provide corrosion control recommendations, failure analysis investigations, sell corrosion control products, or provide installation or design of corrosion control and monitoring systems. Every material has its weakness. Aluminum, galvanized/zinc coatings, brass, and copper do not survive well in very alkaline or very acidic pH environments. Copper and brasses do not survive well in high nitrate or ammonia environments. Carbon steels and iron do not survive well in low soil resistivity and high chloride environments. High chloride environments can even overcome and attack steel encased in normally protective concrete. Concrete does not survive well in high sulfate and acidic environments. And nothing survives well in high sulfide and low redox potential environments with corrosive bacteria. This is called Biogenic sulfide corrosion. | 0 | Metallurgy |
In materials science, a grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are two-dimensional defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material. Most grain boundaries are preferred sites for the onset of corrosion and for the precipitation of new phases from the solid. They are also important to many of the mechanisms of creep. On the other hand, grain boundaries disrupt the motion of dislocations through a material, so reducing crystallite size is a common way to improve mechanical strength, as described by the Hall–Petch relationship. | 0 | Metallurgy |
The extensive processing of eukaryotic pre-mRNA that leads to the mature mRNA is the RNA splicing, a mechanism by which introns or outrons (non-coding regions) are removed and exons (coding regions) are joined. | 1 | Gene expression + Signal Transduction |
A codon table can be used to translate a genetic code into a sequence of amino acids. The standard genetic code is traditionally represented as an RNA codon table, because when proteins are made in a cell by ribosomes, it is messenger RNA (mRNA) that directs protein synthesis. The mRNA sequence is determined by the sequence of genomic DNA. In this context, the standard genetic code is referred to as translation table 1. It can also be represented in a DNA codon table. The DNA codons in such tables occur on the sense DNA strand and are arranged in a 5-to-3 direction. Different tables with alternate codons are used depending on the source of the genetic code, such as from a cell nucleus, mitochondrion, plastid, or hydrogenosome.
There are 64 different codons in the genetic code and the below tables; most specify an amino acid. Three sequences, UAG, UGA, and UAA, known as stop codons, do not code for an amino acid but instead signal the release of the nascent polypeptide from the ribosome. In the standard code, the sequence AUG—read as methionine—can serve as a start codon and, along with sequences such as an initiation factor, initiates translation. In rare instances, start codons in the standard code may also include GUG or UUG; these codons normally represent valine and leucine, respectively, but as start codons they are translated as methionine or formylmethionine.
The first table—the standard table—can be used to translate nucleotide triplets into the corresponding amino acid or appropriate signal if it is a start or stop codon. The second table, appropriately called the inverse, does the opposite: it can be used to deduce a possible triplet code if the amino acid is known. As multiple codons can code for the same amino acid, the International Union of Pure and Applied Chemistry's (IUPAC) nucleic acid notation is given in some instances. | 1 | Gene expression + Signal Transduction |
As shrink fitting requires a uniform heating of the component to be expanded, it is best to try to use the lowest practical frequency when approaching heating for shrink fitting. Again the exception to this rule can be when removing parts from shafts. | 0 | Metallurgy |
TFIIB is a single 33kDa polypeptide consisting of 316 amino acids. TFIIB is made up of four functional regions: the C-terminal core domain; the B linker; the B reader and the amino terminal zinc ribbon.
TFIIB makes protein-protein interactions with the TATA-binding protein (TBP) subunit of transcription factor IID, and the RPB1 subunit of RNA polymerase II.
TFIIB makes sequence-specific protein-DNA interactions with the B recognition element (BRE), a promoter element flanking the TATA element. | 1 | Gene expression + Signal Transduction |
Arnold Adolph Berthold was a German physiologist and zoologist, who, in 1849, had a question about the function of the testes. He noticed in castrated roosters that they did not have the same sexual behaviors as roosters with their testes intact. He decided to run an experiment on male roosters to examine this phenomenon. He kept a group of roosters with their testes intact, and saw that they had normal sized wattles and combs (secondary sexual organs), a normal crow, and normal sexual and aggressive behaviors. He also had a group with their testes surgically removed, and noticed that their secondary sexual organs were decreased in size, had a weak crow, did not have sexual attraction towards females, and were not aggressive. He realized that this organ was essential for these behaviors, but he did not know how. To test this further, he removed one testis and placed it in the abdominal cavity. The roosters acted and had normal physical anatomy. He was able to see that location of the testes does not matter. He then wanted to see if it was a genetic factor that was involved in the testes that provided these functions. He transplanted a testis from another rooster to a rooster with one testis removed, and saw that they had normal behavior and physical anatomy as well. Berthold determined that the location or genetic factors of the testes do not matter in relation to sexual organs and behaviors, but that some chemical in the testes being secreted is causing this phenomenon. It was later identified that this factor was the hormone testosterone. | 1 | Gene expression + Signal Transduction |
Subsets and Splits