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The inositol-phospholipid signaling pathway is responsible for the generation of IP3 through the cleavage of Phosphatidylinositol 4,5-bisphosphate (PIP2) found in the lipid bi-layer of the plasma membrane by phospholipase C in response to either receptor tyrosine kinase or Gq alpha subunit-G protein-coupled receptor signaling. Soluble inositol trisphosphate (IP3) is able to rapidly diffuse into the cytosol and bind to the inositol trisphosphate receptor (InsP3Rs) calcium channels located in the endoplasmic reticulum. This releases calcium into the cytosol, serving as a rapid and potent signal for various cellular processes.
Further reading: Function of calcium in humans | 1 | Gene expression + Signal Transduction |
Zinc refining is the process of purifying zinc to special high grade (SHG) zinc, which is at least 99.995% pure. This process is not usually required when smelting of zinc is done through electrolysis processes, but is needed when zinc is produced by pyrometallurgical processes, because it is only 98.5% pure.
There are various refining methods, but the refluxing process is the most commonly used.
High purity zinc is required industrially to avoid zinc pest, a slow distortion and cracking of zinc die castings caused by impurities precipitating out. | 0 | Metallurgy |
The dbEST is a division of Genbank established in 1992. As for GenBank, data in dbEST is directly submitted by laboratories worldwide and is not curated. | 1 | Gene expression + Signal Transduction |
The TRAFAC class of G domain proteins is named after the prototypical member, the translation factor G proteins. They play roles in translation, signal transduction, and cell motility. | 1 | Gene expression + Signal Transduction |
During the submerged arc welding process, not all flux turns into slag. Depending on the welding process, 50% to 90% of the flux can be reused. | 0 | Metallurgy |
AGA and AGG were thought to have become mitochondrial stop codons early in vertebrate evolution. However, at least in humans it has now been shown that AGA and AGG sequences are not recognized as termination codons. A -1 mitoribosome frameshift occurs at the AGA and AGG codons predicted to terminate the CO1 and ND6 open reading frames (ORFs), and consequently both ORFs terminate in the standard UAG codon. | 1 | Gene expression + Signal Transduction |
The compound has been prepared in a multistep process starting with the base hydrolysis of phosphorus pentasulfide:
:PS + 6 NaOH → 2 NaPOS + HS + 2 HO
The salt is isolated as the hydrate NaPOS(HO). It is prone to hydrolysis, especially when it is heated as an aqueous solutions:
:NaPOS + 2 HO → NaPOS + HS
Its structure has been examined by X-ray crystallography. | 0 | Metallurgy |
Dithionite is used in conjunction with complexing agents (for example, citric acid) to reduce iron(III) oxy-hydroxide into soluble iron(II) compounds and to remove amorphous iron(III)-bearing mineral phases in soil analyses (selective extraction).
The decomposition of dithionite produces reduced species of sulfur that can be very aggressive for the corrosion of steel and stainless steel. Thiosulfate () is known to induce pitting corrosion, whereas sulfide (S, HS) is responsible for stress corrosion cracking (SCC). | 0 | Metallurgy |
A liquid metal is a metal or a metal alloy which is liquid at or near room temperature.
The only stable liquid elemental metal at room temperature is mercury (Hg), which is molten above −38.8 °C (234.3 K, −37.9 °F). Three more stable elemental metals melt just above room temperature: caesium (Cs), which has a melting point of 28.5 °C (83.3 °F); gallium (Ga) (30 °C [86 °F]); and rubidium (Rb) (39 °C [102 °F]). The radioactive metal francium (Fr) is probably liquid close to room temperature as well. Calculations predict that the radioactive metals copernicium (Cn) and flerovium (Fl) should also be liquid at room temperature.
Alloys can be liquid if they form a eutectic, meaning that the alloys melting point is lower than any of the alloys constituent metals. The standard metal for creating liquid alloys used to be mercury, but gallium-based alloys, which are lower both in their vapor pressure at room temperature and toxicity, are being used as a replacement in various applications. | 0 | Metallurgy |
The basic LPB tool is a ball, wheel or other similar tip that is supported in a spherical hydrostatic bearing. The tool can be held in any CNC machine or by industrial robots, depending on the application. The machine tool coolant is used to pressurize the bearing with a continuous flow of fluid to support the ball. The ball does not contact the mechanical bearing seat, even under load. The ball is loaded at a normal state to the surface of a component with a hydraulic cylinder that is in the body of the tool. LPB can be performed in conjunction with chip forming machining operations in the same CNC machining tool.
The ball rolls across the surface of a component in a pattern defined in the CNC code, as in any machining operation. The tool path and normal pressure applied are designed to create a distribution of compressive residual stress. The form of the distribution is designed to counter applied stresses and optimize fatigue and stress corrosion performance. Since there is no shear being applied to the ball, it is free to roll in any direction. As the ball rolls over the component, the pressure from the ball causes plastic deformation to occur in the surface of the material under the ball. Since the bulk of the material constrains the deformed area, the deformed zone is left in compression after the ball passes. | 0 | Metallurgy |
*ANXA6
*ANXA7
*ARPC1A Actin-related peptide
*ARPC2
*ARPC5L
*CAPZA2
*CAPZB
*RHOA also implicated in regulation of cell cycle
*RHOB
*RHOT1 mitochondrial trafficking
*RHOT2
*TUBB Tubulin, beta polypeptide
*WDR1 actin disassembly? | 1 | Gene expression + Signal Transduction |
Many types of arrays exist and the broadest distinction is whether they are spatially arranged on a surface or on coded beads:
* The traditional solid-phase array is a collection of orderly microscopic "spots", called features, each with thousands of identical and specific probes attached to a solid surface, such as glass, plastic or silicon biochip (commonly known as a genome chip, DNA chip or gene array). Thousands of these features can be placed in known locations on a single DNA microarray.
* The alternative bead array is a collection of microscopic polystyrene beads, each with a specific probe and a ratio of two or more dyes, which do not interfere with the fluorescent dyes used on the target sequence.
DNA microarrays can be used to detect DNA (as in comparative genomic hybridization), or detect RNA (most commonly as cDNA after reverse transcription) that may or may not be translated into proteins. The process of measuring gene expression via cDNA is called expression analysis or expression profiling.
Applications include:
Specialised arrays tailored to particular crops are becoming increasingly popular in molecular breeding applications. In the future they could be used to screen seedlings at early stages to lower the number of unneeded seedlings tried out in breeding operations. | 1 | Gene expression + Signal Transduction |
Janot studied physics and mathematics at the University of Dijon and later joined Armand Hadni at University of Nancy, where he received his PhD in 1963. Janot was one of the founding directors of the Jean Lamour Institute, a joint research institute between CNRS and the University of Lorraine. Between 1982 and 1991, Janot was appointed senior scientist at Institut Laue Langevin in Grenoble, France, and retained a long-term visitor position afterwards. During this period, Janot also became a professor at Joseph Fourier University (later part of Grenoble Alpes University).
Janot cowrote several textbooks in physics and materials science. Nobel Laureate Dan Shechtman wrote a forward for his classic monograph on quasicrystals. | 0 | Metallurgy |
Hydrocarbon utilizing microorganisms, mostly Cladosporium resinae and Pseudomonas aeruginosa and sulfate reducing bacteria, colloquially known as "HUM bugs", are commonly present in jet fuel. They live in the water-fuel interface of the water droplets, form dark black/brown/green, gel-like mats, and cause microbial corrosion to plastic and rubber parts of the aircraft fuel system by consuming them, and to the metal parts by the means of their acidic metabolic products. They are also incorrectly called algae due to their appearance. FSII, is added to fuel as a growth retardant. There are about 250 kinds of bacteria that can live in jet fuel, but fewer than a dozen are meaningfully harmful. | 0 | Metallurgy |
Self-heating cans of military food rations developed during WWII used a thermite-like mixture of 1:1 iron(II,III) oxide and calcium silicide. Such mixture, when ignited, generates moderate amount of heat and no gaseous products. | 0 | Metallurgy |
Activation of the ERK1/2 pathway by aberrant RAS/RAF signalling, DNA damage, and oxidative stress leads to cellular senescence. Low doses of DNA damage resulting from cancer therapy cause ERK1/2 to induce senescence, whereas higher doses of DNA damage fail to activate ERK1/2, and thus induce cell death by apoptosis. | 1 | Gene expression + Signal Transduction |
Nickel-cobalt lateritic ores can be treated by either hydrometallurgical processes or pyrometallurgical processes, such as matte or ferronickel smelting, which require the entire ore to be melted and the metal values to be separated from the residual components of the ore. The hydrometallurgical process for laterite ore can use sulfuric acid or ammonia leach solutions. | 0 | Metallurgy |
Tamm et al. have shown that survivin inhibits both Bax and Fas-induced apoptotic pathways. The experiment involved transfecting HEK 293 cells with a Bax-encoding plasmid, which resulted in an increase in apoptosis (~7 fold) as measured by DAPI staining. They then contransfected the 293 cells with Bax-encoding plasmid and survivin-encoding plasmids. They observed that cells transfected along with the survivin showed a significant decrease in apoptosis (~3 fold). A similar result also showed for cells transfected with the Fas-overexpressing plasmid. Immunoblots were performed and confirmed that survivin does not inhibit by mechanism of preventing Bax or Fas protein from being made into fully functional proteins. Therefore, survivin should be acting somewhere downstream of the Bax or Fas signaling pathway to inhibit apoptosis through these pathways. | 1 | Gene expression + Signal Transduction |
* Endomycetales (yeasts): Candida albicans, Candida cylindracea, Candida melibiosica, Candida parapsilosis, and Candida rugosa. | 1 | Gene expression + Signal Transduction |
Swedish law required bars of iron to have the forges mark stamped into it for quality control reasons. In Britain, the iron was known by these marks', and the quality of each brand was well-known to the buyers in London, Sheffield, Birmingham and elsewhere. It was divided into two grades:
* First oregrounds came from Österby (double bullet), Leufsta (now Lövsta - hoop L), and Åkerby (PL crown). Later Gimo joined them.
* Second oregrounds came from the other forges, including Forsmark, Harg, Vattholma, and Ullfors.
Its special property was its purity. The manganese content of the Dannemora ore caused impurities, which would otherwise have remained in the iron, to react preferentially with the manganese and to be carried off into the slag. This level of purity meant that the iron was particularly suitable for conversion to steel by being re-carburized, using the cementation process. This made it particularly suitable for making steel, oregrounds iron was an indispensable raw material for metal manufactures, particularly the Sheffield cutlery industry. Substantial quantities were also (until about 1808) bought for use by the British Navy.
This and other uses absorbed substantially the whole output of the industry. The trade in oregrounds iron was controlled from the 1730s to the 1850s by a cartel of merchants, of whom the longest enduring members were the Sykes family of Hull. Other participants were resident in (or controlling imports through) London and Bristol. These merchants advanced money to Swedish exporting houses, which in turn advanced it to the ironmasters, thus buying up the output of the forges several years in advance. | 0 | Metallurgy |
During the Dark Ages of the transition from bronze to iron, the decorative arts stood almost still but industrial metalwork was freely produced. There are a few remains of Geometric bronze vessels, but as in the case of the Early Minoan material, metal forms are recorded in their pottery derivatives. Some vase-shapes are clearly survivals from the Mycenaean repertory, but a greater number are new, and these are elementary and somewhat clumsy, spherical or biconical bodies, huge cylindrical necks with long band-handles and no spouts. Ceramic painted ornament also reflects originals of metal, and some scraps of thin bronze plate embossed with rows of knobs and lightly engraved in hatched or zig-zag outline doubtless represent the art which the newcomers brought with them to Greek lands. This kind of decorative work is better seen in bronzes of the closely related Villanova culture of north and central Italy. A novel feature is the application of small figures in the round, particularly birds and heads of oxen, as ornaments of handles, lids and rims. The Italian Geometric style developed towards complication, in crowded narrow bands of conventional patterns and serried rows of ducks; but contemporary Greek work was a refinement of the same crude elements.
Engraving appears at its best on the large catch-plates of fibulae, some of which bear the earliest known pictures of Hellenic mythology. Small statuettes of animals were made for votive use and also served as seals, the devices being cast underneath their bases. There is a large series of such figures, mostly horses, standing on engraved or perforated plates, which were evidently derived from seals; among the later examples are groups of men and centaurs. Pieces of tripod-cauldrons from Olympia have animals lying or standing on their upright ring-handles, which are steadied by human figures on the rims. Handles and legs are cast, and are enriched with graceful geometric mouldings. The bowls are wrought, and their shape and technique are pre-Hellenic. Here are two of the elements of classical Greek art in full course of development: the forms and processes of earlier times invigorated by a new aesthetic sense. | 0 | Metallurgy |
The process produces a quantity of fluoride waste: perfluorocarbons and hydrogen fluoride as gases, and sodium and aluminium fluorides and unused cryolite as particulates. This can be as small as 0.5 kg per tonne of aluminium in the best plants in 2007, up to 4 kg per tonne of aluminium in older designs in 1974. Unless carefully controlled, hydrogen fluorides tend to be very toxic to vegetation around the plants.
The Soderberg process which bakes the Anthracite/pitch mix as the anode is consumed, produces significant emissions of polycyclic aromatic hydrocarbons as the pitch is consumed in the smelter.
The linings of the pots end up contaminated with cyanide-forming materials; Alcoa has a process for converting spent linings into aluminium fluoride for reuse and synthetic sand usable for building purposes and inert waste. | 0 | Metallurgy |
Sand casting is one of the most popular and simplest types of casting, and has been used for centuries. Sand casting allows for smaller batches than permanent mold casting and at a very reasonable cost. Not only does this method allow manufacturers to create products at a low cost, but there are other benefits to sand casting, such as very small-size operations. The process allows for castings small enough fit in the palm of one's hand to those large enough for a train car bed (one casting can create the entire bed for one rail car). Sand casting also allows most metals to be cast depending on the type of sand used for the molds.
Sand casting requires a lead time of days, or even weeks sometimes, for production at high output rates (1–20 pieces/hr-mold) and is unsurpassed for large-part production. Green (moist) sand, which is black in color, has almost no part weight limit, whereas dry sand has a practical part mass limit of . Minimum part weight ranges from . The sand is bonded using clays, chemical binders, or polymerized oils (such as motor oil). Sand can be recycled many times in most operations and requires little maintenance. | 0 | Metallurgy |
Pitting corrosion, or pitting, is a form of extremely localized corrosion that leads to the random creation of small holes in metal. The driving power for pitting corrosion is the depassivation of a small area, which becomes anodic (oxidation reaction) while an unknown but potentially vast area becomes cathodic (reduction reaction), leading to very localized galvanic corrosion. The corrosion penetrates the mass of the metal, with a limited diffusion of ions.
Another term arises, pitting factor, which is defined as the ratio of the depth of the deepest pit (resulting due to corrosion) to the average penetration, which can be calculated based on the weight loss. | 0 | Metallurgy |
Mechanically, NbSn is extremely brittle and thus cannot be easily drawn into a wire, which is necessary for winding superconducting magnets. To overcome this, wire manufacturers typically draw down composite wires containing ductile precursors. The "internal tin" process includes separate alloys of Nb, Cu and Sn. The "bronze" process contains Nb in a copper–tin bronze matrix. With both processes the strand is typically drawn to final size and coiled into a solenoid or cable before heat treatment. It is only during heat treatment that the Sn reacts with the Nb to form the brittle, superconducting niobium–tin compound. The powder-in-tube process is also used.
The high field section of modern NMR magnets are composed of niobium–tin wire. | 0 | Metallurgy |
ITPP is a membrane-permeant allosteric regulator of hemoglobin that mildly reduces its oxygen-binding affinity, which shifts the oxygen-hemoglobin dissociation curve to the right and thereby increases oxygen release from the blood into tissue. Phytic acid, in contrast, is not membrane-permeant due to its charge distribution.
Rodent studies in vivo demonstrated increased tissue oxygenation and dose-dependent increases in endurance during physical exercise, in both healthy mice and transgenic mice expressing a heart failure phenotype.
The substance is believed to have a high potential for use in athletic doping, and liquid chromatography–mass spectrometry tests have been developed to detect ITPP in urine tests. Its use as a performance-enhancing substance in horse racing has also been suspected and similar tests have been developed for horses
ITPP has been studied for potential adjuvant use in the treatment of cancer in conjunction with chemotherapy, due to its effects in reducing tissue hypoxia. Human clinical trials were registered in 2014 under the compound number OXY111A. The substance has also been examined in the context of other illnesses involving hypoxia, such as cardiovascular disease and dementia | 1 | Gene expression + Signal Transduction |
In Mesopotamia, from –2750 BC, the lost-wax technique was used for small-scale, and then later large-scale copper and bronze statues. One of the earliest surviving lost-wax castings is a small lion pendant from Uruk IV. Sumerian metalworkers were practicing lost-wax casting from approximately –3200 BC. Much later examples from northeastern Mesopotamia/Anatolia include the Great Tumulus at Gordion (late 8th century BC), as well as other types of Urartian cauldron attachments. | 0 | Metallurgy |
Copper and its alloys can be finished to embark a particular look, feel, and/or color. Finishes include mechanical surface treatments, chemical coloring, and coatings. These are described here.
Mechanical surface treatments. Several types of mechanical surface treatments exist. Mill finishes are derived by normal production processes, such as rolling, extrusion, or casting. "Buffeted" finishes impart bright mirror-like appearances after grinding, polishing, and buffing. "Directional textured" finishes provide a smooth, velvety satin sheen in a continuous pattern of fine nearly parallel scratches. "Non-directional textured matte" finishes achieve a rough texture, primarily on castings, as spray sand or metal shot are applied under high pressure. And "patterned" finishes, made by pressing a copper alloy sheet between two rolls, produce a textured and embossed look.
Chemically induced patina. Architects sometimes request a particular patina color at installation. Factory-applied chemically induced pre-patination systems can produce a wide range of colored finishes similar to natural patination. Pre-patinated copper is particularly useful in repairs when there is need to provide close color matches to old copper roofs. Pre-patination is also considered in some modern building materials, such as vertical cladding, soffits, and gutters where patination is desired but would not ordinarily occur.
Chemical coloring of metals is an art involving craftsmanship and experience. Coloring techniques depend upon time, temperature, surface preparation, humidity and other variables. Pre-patinated copper sheets are produced by fabricators under controlled environments using patented chemical processes. Green patina finishes are primarily developed using acid chloride or acid sulfate. Treatments with ammonium chloride (sal ammoniac), cuprous chloride/hydrochloric acid, and ammonium sulfate are somewhat successful. Statuary finishes can be produced in light, medium, and dark brown, depending on the concentration and number of coloring applications. One advantage is that the treatment disguises surface markings on bright mill finish copper and can advance the natural patination process.
Because of the number of variables involved, chemically induced patinas are prone to problems such as a lack of adhesion, excessive staining of adjacent materials, and inability to achieve reasonable color uniformity over large surface areas. Chemical patination applied in the field is not recommended due to variations in temperature, humidity, and chemical requirements. Warranties are prudent when purchasing pre-patinated copper for architectural projects.
Useful techniques and recipes for coloring copper, brass, yellow-brass, bronze, cast bronze, gilding metal, along with various physical and chemical textural finishes are available.
Coatings. Clear coatings preserve the natural color, warmth and metallic tone of copper alloys. However, particularly on exterior applications, they introduce maintenance into what is naturally a maintenance-free material. They are organic chemicals that are dry at ambient temperatures or require heat for curing or solvent evaporation. Examples of clear organic coatings include alkyd, acrylic, cellulose acetate butyrate, epoxy, nitrocellulose, silicone, and urethane. Further details are available.
Oils and waxes exclude moisture from copper surfaces and simultaneously enhance their appearance by bringing out a rich luster and depth of color. Oiling is typically used to prolong the time exposed copper remains in a brown to black tone. It will not keep copper shiny on an exterior installation. Oils and waxes offer short-term protection for exterior applications and longer-term protection for interior applications.
Oiling predominates for roofing and flashing work. The most popular oils are Lemon Oil, U.S.P., Lemon Grass Oil, Native E.I., paraffin oils, linseed oil, and castor oil. On copper roofing or flashing, reapplication as infrequently as once every three years can effectively retard patina formation. In arid climates, the maximum span between oilings may be extended to from three to five years.
Waxing is generally reserved for architectural components subject to close inspection and/or traffic. Mixes considered satisfactory include Carnauba wax and wood turpentine, or beeswax and wood turpentine, or paste waxes.
Opaque paint coatings are used primarily for work applied over copper when substrate integrity and longevity are desired but a specific color other than the naturally occurring copper hues is required.
Zinc-tin coatings are an alternative to lead coatings since they have approximately the same appearance and workability.
Vitreous enamel coatings are used primarily for art work over copper.
More details on copper finishes are available. | 0 | Metallurgy |
Casein kinase 1 epsilon has been suggested to play a role in phosphorylation of Disheveled in the Wnt signaling pathway. Casein kinase 1 alpha (CK1α) binds to and phosphorylates β‑catenin
In plants the phosphorylation of protein Jade-1 is regulated by casein kinase 1. In humans there are three casein kinase 1 gamma enzymes.
Xenopus casein kinase 1 gamma (CK1gamma) is associated with the cell membrane and binds to LRP. CK1gamma was found to be needed for Wnt signaling through LRP, and is both necessary and sufficient to transduce LRP6 signaling in vertebrates and Drosophila cells. Wnt binding to LRP causes a rapid increase in phosphorylation of the cytoplasmic domain of LRP by CK1gamma. Phosphorylation of LRP6 by CK1gamma promotes binding of axin to LRP and activation of the Wnt signaling pathway. | 1 | Gene expression + Signal Transduction |
The process is named after the Italian physician, physicist, biologist and philosopher Luigi Galvani (9 September 1737 – 4 December 1798). The earliest known example of galvanized iron was discovered on 17th-century Indian armour in the Royal Armouries Museum collection in the United Kingdom.
The term "galvanized" can also be used metaphorically of any stimulus which results in activity by a person or group of people.
In modern usage, the term "galvanizing" has largely come to be associated with zinc coatings, to the exclusion of other metals. Galvanic paint, a precursor to hot-dip galvanizing, was patented by Stanislas Sorel, of Paris, on June 10, 1837, as an adoption of a term from a highly fashionable field of contemporary science, despite having no evident relation to it. | 0 | Metallurgy |
Galvanic corrosion is an electrochemical process whereby one metal corrodes preferentially to another when both metals are in electrical contact with each other in the presence of an electrolyte, such as moisture and salts. This is because the dissimilar metals have different electrode potentials. The potential difference between the dissimilar metals is the driving force for the accelerated attack on the metal with the lower galvanic number (i.e., the anode). Over time, the anode metal dissolves into the electrolyte.
Metals are ranked according to galvanic numbers as a qualitative measure of their nobility. These numbers qualify the resistance to corrosion of any metal when in contact with other metals. A larger difference in the galvanic number between two metals in contact with each other indicates a greater potential for corrosion.
The galvanic numbers of the most common metals used in construction are ranked as follows: 1. aluminium; 2. zinc; 3. steel; 4. iron; 5. stainless steel - active; 6. tin; 7. lead; 8. copper; 9. stainless steel - passive.
Galvanic corrosion is a primary concern with metal roof maintenance. Marine environments present an additional concern due to the higher concentration of salts in the air and water.
Copper is one of the most noble metals. It will not be harmed by contact with other metals but it will cause corrosion to some other metals if contacted directly. The principal metals of concern regarding direct contact with copper are aluminium, light-gauge steel, and zinc. Aluminium and steel flashings and galvanized steel fasteners should not be used with copper. Runoff from a copper roof corrodes aluminium and steel guttering. It is not necessary to isolate copper from lead, tin or many stainless steels under most circumstances.
When it is not possible to avoid contact, an effective method of material separation is required. If paints or coatings are used for isolation, they should be compatible with both metals. Bituminous or zinc chromate primers can be used between copper and aluminium. Bituminous, zinc chromate, or a red lead primer can be effective in separating copper from iron and other ferrous metals. Taping or gasketing with non-absorptive materials or sealants are effective in separating copper from all other metals. In areas with severe exposure, lead or similar gasketing materials should be used, except between copper and aluminium. Water draining from copper surfaces should be prevented from exposure to aluminium and galvanized steel as traces of copper salts may accelerate corrosion. In some cases, anodizing may protect thicker aluminium, such as aluminium window system mullions. | 0 | Metallurgy |
Some sulfate-reducing bacteria produce hydrogen sulfide, which can cause sulfide stress cracking. Acidithiobacillus bacteria produce sulfuric acid; Acidothiobacillus thiooxidans frequently damages sewer pipes. Ferrobacillus ferrooxidans directly oxidizes iron to iron oxides and iron hydroxides; the rusticles forming on the RMS Titanic wreck are caused by bacterial activity. Other bacteria produce various acids, both organic and mineral, or ammonia.
In presence of oxygen, aerobic bacteria like Acidithiobacillus thiooxidans, Thiobacillus thioparus, and Thiobacillus concretivorus, all three widely present in the environment, are the common corrosion-causing factors resulting in biogenic sulfide corrosion.
Without presence of oxygen, anaerobic bacteria, especially Desulfovibrio and Desulfotomaculum, are common. Desulfovibrio salixigens requires at least 2.5% concentration of sodium chloride, but D. vulgaris and D. desulfuricans can grow in both fresh and salt water. D. africanus is another common corrosion-causing microorganism. The genus Desulfotomaculum comprises sulfate-reducing spore-forming bacteria; Dtm. orientis and Dtm. nigrificans are involved in corrosion processes. Sulfate-reducers require a reducing environment; an electrode potential lower than -100 mV is required for them to thrive. However, even a small amount of produced hydrogen sulfide can achieve this shift, so the growth, once started, tends to accelerate.
Layers of anaerobic bacteria can exist in the inner parts of the corrosion deposits, while the outer parts are inhabited by aerobic bacteria.
Some bacteria are able to utilize hydrogen formed during cathodic corrosion processes.
Bacterial colonies and deposits can form concentration cells, causing and enhancing galvanic corrosion. [https://web.archive.org/web/20060504072637/http://httd.njuct.edu.cn/MatWeb/corrosie/c_bio.htm].
Bacterial corrosion may appear in form of pitting corrosion, for example in pipelines of the oil and gas industry. Anaerobic corrosion is evident as layers of metal sulfides and hydrogen sulfide smell. On cast iron, a graphitic corrosion selective leaching may be the result, with iron being consumed by the bacteria, leaving graphite matrix with low mechanical strength in place.
Various corrosion inhibitors can be used to combat microbial corrosion. Formulae based on benzalkonium chloride are common in oilfield industry.
Microbial corrosion can also apply to plastics, concrete, and many other materials. Two examples are Nylon-eating bacteria and Plastic-eating bacteria. | 0 | Metallurgy |
For a targeted treatment, the visibility and accessibility of the transition in the welded areas are required.
Existing structures typically are prepared at the transition for surface finishing. The parts must be free of loose rust and old paint. If necessary, previous sandblasting is required.
The device operates with a compressed air supply of 6–8 bar. | 0 | Metallurgy |
In a crystalline material, a dislocation is capable of traveling throughout the lattice when relatively small stresses are applied. This movement of dislocations results in the material plastically deforming. Pinning points in the material act to halt a dislocation's movement, requiring a greater amount of force to be applied to overcome the barrier. This results in an overall strengthening of materials. | 0 | Metallurgy |
Mechanical alloying (MA) is a solid-state and powder processing technique involving repeated cold welding, fracturing, and re-welding of blended powder particles in a high-energy ball mill to produce a homogeneous material. Originally developed to produce oxide-dispersion strengthened (ODS) nickel- and iron-base superalloys for applications in the aerospace industry, MA has now been shown to be capable of synthesizing a variety of equilibrium and non-equilibrium alloy phases starting from blended elemental or pre-alloyed powders. The non-equilibrium phases synthesized include supersaturated solid solutions, metastable crystalline and quasicrystalline phases, nanostructures, and amorphous alloys. | 0 | Metallurgy |
Most human cancers have been found to have gains and losses of chromosomes that may be due to chromosomal instability (CIN). One of the things that cause CIN is the inactivation of genes that control the proper segregation of the sister chromatids during mitosis. In gaining a better understanding of survivin's function in mitotic regulation, scientists have looked into the area of genomic instability. It is known that survivin associates with microtubules of the mitotic spindle at the start of mitosis.
It has been shown in the literature that knocking out survivin in cancer cells will disrupt microtubule formation and result in polyploidy as well as massive apoptosis. It has also been shown that survivin-depleted cells exit mitosis without achieving proper chromosome alignment and then reforms single tetraploid nuclei. Further evidence also suggests that survivin is needed for sustaining mitotic arrest upon encounter with mitosis problems. The evidence mentioned above implicates that survivin plays an important regulatory role both in the progression of mitosis and sustaining mitotic arrest. This seems strange, as survivin is known to be highly upregulated in most cancer cells (that usually contain chromosome instability characteristics), and its function is that which promotes proper regulation of mitosis. | 1 | Gene expression + Signal Transduction |
Some early literary works allude to lost-wax casting. Columella, a Roman writer of the 1st century AD, mentions the processing of wax from beehives in De Re Rustica, perhaps for casting, as does Pliny the Elder, who details a sophisticated procedure for making Punic wax. One Greek inscription refers to the payment of craftsmen for their work on the Erechtheum in Athens (408/7–407/6 BC). Clay-modellers may use clay moulds to make terracotta negatives for casting or to produce wax positives. Pliny portrays as a well-reputed ancient artist producing bronze statues, and describes Lysistratos of Sikyon, who takes plaster casts from living faces to create wax casts using the indirect process.
Many bronze statues or parts of statues in antiquity were cast using the lost wax process. Theodorus of Samos is commonly associated with bronze casting. Pliny also mentions the use of lead, which is known to help molten bronze flow into all areas and parts of complex moulds. Quintilian documents the casting of statues in parts, whose moulds may have been produced by the lost wax process. Scenes on the early-5th century BC Berlin Foundry Cup depict the creation of bronze statuary working, probably by the indirect method of lost-wax casting. | 0 | Metallurgy |
As widely accepted as this statement might be, it should not be considered synonymous with a lack of metal objects, as it points out native copper was relatively abundant, particularly in the Great Lakes region. The latest glacial period had resulted in the scouring of copper bearing rocks. Once the ice retreated, these were readily available for use in a variety of sizes. Copper was shaped via cold hammering into objects from very early dates (Archaic period in the Great Lakes region: 8000–1000 BCE). There is also evidence of actual mining of copper veins (Old Copper Complex), but disagreement exists as to the dates.
Extraction would have been extremely difficult. Hammerstones may have been used to break off pieces small enough to be worked. This labor-intensive process might have been eased by building a fire on top of the deposit, then quickly dousing the hot rock with water, creating small cracks. This process could be repeated to create more small cracks.
The copper could then be cold-hammered into shape, which would make it brittle, or hammered and heated in an annealing process to avoid this. The final object would then have to be ground and sharpened using local sandstone. Numerous bars have also been found, possibly indicative of trade for which their shaping into a bar would also serve as proof of quality.
Great Lake artifacts found in the Eastern Woodlands of North America seem to indicate there were widespread trading networks by 1000 BCE. Progressively the usage of copper for tools decreases with more jewelry and adornments being found. This is believed to be indicative of social changes to a more hierarchical society. Thousands of copper mining pits have been found along the lake shore of Lake Superior, and on Isle Royale. These pits may have been in use as far back as 8,000 years ago. This copper was mined and then made into objects such as heavy spear points and tools of all kinds. It was also made into mysterious crescent objects that some archaeologists believe were religious or ceremonial items. The crescents were too fragile for utilitarian use, and many have 28 or 29 notches along the inner edge, the approximate number of days in a lunar month.The Old Copper Culture mainly flourished in Ontario and Minnesota. However at least 50 Old Copper items, including spear points and ceremonial crescents have been discovered in Manitoba. A few more in Saskatchewan, and at least one, a crescent, has turned up in Alberta, 2,000 kilometres from its homeland in Ontario. It is most likely that these copper items arrived in the plains as trade goods rather than people of the Old Copper Culture moving into these new places. However from one excavated site in eastern Manitoba we can see that at least some people were moving northwest. At a site near Bissett archaeologists have found copper tools, weapons, and waste material of manufacture, along with a large nugget of raw copper. This site however was dated to around 4,000 years ago, a time of cooler climate when the boreal forest's treeline moved much further south. Though if these migrants moved with their metallurgy up the Winnipeg River at this time they may have continued onward, into Lake Winnipeg, and the Saskatchewan River system.
This Old Copper Culture never became particularity advanced, and never discovered the principle of creating alloys. This means that many, though they could make metal objects and weapons, continued to use their flint tools, which could maintain a sharper edge for much longer. The unalloyed copper could simply not compete, and in the later days of the Old Copper Culture the metal was almost exclusively used for ceremonial items.
However this Great Lake model as a unique source of copper and of copper technologies remaining somewhat static for over 6,000 years has recently come into some level of criticism, particularly since other deposits seem to have been available to ancient North Americans, even if much smaller. | 0 | Metallurgy |
Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte. A similar galvanic reaction is exploited in primary cells to generate a useful electrical voltage to power portable devices. This phenomenon is named after Italian physician Luigi Galvani (1737–1798). | 0 | Metallurgy |
In contact with water, hydrogen is created. Hence, sodium–potassium alloys are used as desiccants in drying solvents prior to distillation. | 0 | Metallurgy |
One theme of research in evolutionary developmental biology ("evo-devo") is investigating the role of enhancers and other cis-regulatory elements in producing morphological changes via developmental differences between species. | 1 | Gene expression + Signal Transduction |
Intrinsic transcription terminators or Rho-independent terminators require the formation of a self-annealing hairpin structure on the elongating transcript, which results in the disruption of the mRNA-DNA-RNA polymerase ternary complex. The terminator sequence in DNA contains a 20 basepair GC-rich region of dyad symmetry followed by a short poly-A tract or "A stretch" which is transcribed to form the terminating hairpin and a 7–9 nucleotide "U tract" respectively. The mechanism of termination is hypothesized to occur through a combination of direct promotion of dissociation through allosteric effects of hairpin binding interactions with the RNA polymerase and "competitive kinetics". The hairpin formation causes RNA polymerase stalling and destabilization, leading to a greater likelihood that dissociation of the complex will occur at that location due to increased time spent paused at that site and reduced stability of the complex.
Additionally, the elongation protein factor NusA interacts with the RNA polymerase and the hairpin structure to stimulate transcriptional termination. | 1 | Gene expression + Signal Transduction |
In 1993, Richard J. Roberts and Phillip Allen Sharp received the Nobel Prize in Physiology or Medicine for their discovery of "split genes". Using the model adenovirus in their research, they were able to discover splicing—the fact that pre-mRNA is processed into mRNA once introns were removed from the RNA segment. These two scientists discovered the existence of splice sites, thereby changing the face of genomics research. They also discovered that the splicing of the messenger RNA can occur in different ways, opening up the possibility for a mutation to occur. | 1 | Gene expression + Signal Transduction |
Since 2007, China has restricted exports of REEs (rare-earth elements) and imposed export tariffs, both to conserve resources and to give preference to Chinese manufacturers. In 2009, China supplied more than 96% of the world's REEs. Some outside China are concerned that because rare-earths are essential to some high-tech, renewable-energy, and defense-related technologies, the world should not be so reliant on a single supplier country
On September 22, 2010, China quietly enacted a ban on exports of rare-earths to Japan, a move suspected to be in retaliation for the Japanese arrest of a Chinese trawler captain in a territorial dispute. Because Japan and China are the only current sources for rare-earth magnetic material used in the US, a permanent disruption of Chinese rare-earth supply to Japan would leave China as the sole source. Jeff Green, a rare-earth lobbyist, said, "We are going to be 100 percent reliant on the Chinese to make the components for the defense supply chain." The House Committee on Science and Technology scheduled on September 23, 2010, the review of a detailed bill to subsidize the revival of the American rare-earths industry, including the reopening of the Mountain Pass mine.
After China doubled import duties on rare-earth concentrates to 25% as a result of the US-China trade war, MP Materials said, in May 2019, it will start its own partial processing operation in the United States, though full processing operations without Shenghe Resources have been delayed. According to Bloomberg, China in 2019 established a plan for restricting U.S. access to Chinese heavy rare earth elements, should the punitive step be deemed necessary. In 2022, the company announced that it had secured Department of Defense grants to support both light rare-earth elements (LREEs) and heavy rare earth elements (HREEs). The facility plans to begin separating NdPr oxide in early 2023. | 0 | Metallurgy |
Because a large portion of the pairs of a and b contain zeros in one or both conditions, they are impossible to plot as-is on a log scale. Other MA plotting functions artificially include these condition-unique points in the plot by spreading them vertically as a "smear" on the left or horizontally as a "[https://web.archive.org/web/20110825045150/http://projetos.inpa.gov.br/i3geo/pacotes/r/win/library/graphics/html/rug.html rug]" at the very top and bottom of the plot. In an RA plot, by contrast, the uniques are included via addition a small epsilon factor (between .1 and .5) which places them in a more statistically appropriate location in the plot. | 1 | Gene expression + Signal Transduction |
Among the array of substrates that can be altered by CK2 many of them have been found in increased prevalence in cancers of the breast, lung, colon, and prostate. An increased concentration of substrates in cancerous cells infers a likely survival benefit to the cell, and activation of many of these substrates requires CK2. As well the anti-apoptotic function of CK2 allows the cancerous cell to escapes cell death and continue proliferating. Having roles in cell cycle regulation may also indicate CK2's role in allowing cell cycle progression when normally it should have been ceased. This also promotes CK2 as a possible therapeutic target for cancer drugs. When added with other potent anti-cancer therapies, a CK2 inhibitor may increase the effectiveness of the other therapy by allowing drug-induced apoptosis to occur at a normal rate. | 1 | Gene expression + Signal Transduction |
The effect of corrosion on a smooth-specimen S-N diagram is shown schematically on the right. Curve A shows the fatigue behavior of a material tested in air. A fatigue threshold (or limit) is seen in curve A, corresponding to the horizontal part of the curve. Curves B and C represent the fatigue behavior of the same material in two corrosive environments. In curve B, the fatigue failure at high stress levels is retarded, and the fatigue limit is eliminated. In curve C, the whole curve is shifted to the left; this indicates a general lowering in fatigue strength, accelerated initiation at higher stresses and elimination of the fatigue limit.
To meet the needs of advancing technology, higher-strength materials are developed through heat treatment or alloying. Such high-strength materials generally exhibit higher fatigue limits, and can be used at higher service stress levels even under fatigue loading. However, the presence of a corrosive environment during fatigue loading eliminates this stress advantage, since the fatigue limit becomes almost insensitive to the strength level for a particular group of alloys. This effect is schematically shown for several steels in the diagram on the left, which illustrates the debilitating effect of a corrosive environment on the functionality of high-strength materials under fatigue.
Corrosion fatigue in aqueous media is an electrochemical behavior. Fractures are initiated either by pitting or persistent slip bands. Corrosion fatigue may be reduced by alloy additions, inhibition and cathodic protection, all of which reduce pitting. Since corrosion-fatigue cracks initiate at a metals surface, surface treatments like plating, cladding, nitriding and shot peening were found to improve the materials resistance to this phenomenon. | 0 | Metallurgy |
Grain boundaries are interfaces where crystals of different orientations meet. A grain boundary is a single-phase interface, with crystals on each side of the boundary being identical except in orientation. The term "crystallite boundary" is sometimes, though rarely, used. Grain boundary areas contain those atoms that have been perturbed from their original lattice sites, dislocations, and impurities that have migrated to the lower energy grain boundary.
Treating a grain boundary geometrically as an interface of a single crystal cut into two parts, one of which is rotated, we see that there are five variables required to define a grain boundary. The first two numbers come from the unit vector that specifies a rotation axis. The third number designates the angle of rotation of the grain. The final two numbers specify the plane of the grain boundary (or a unit vector that is normal to this plane).
Grain boundaries disrupt the motion of dislocations through a material. Dislocation propagation is impeded because of the stress field of the grain boundary defect region and the lack of slip planes and slip directions and overall alignment across the boundaries. Reducing grain size is therefore a common way to improve strength, often without any sacrifice in toughness because the smaller grains create more obstacles per unit area of slip plane. This crystallite size-strength relationship is given by the Hall–Petch relationship. The high interfacial energy and relatively weak bonding in grain boundaries makes them preferred sites for the onset of corrosion and for the precipitation of new phases from the solid.
Grain boundary migration plays an important role in many of the mechanisms of creep. Grain boundary migration occurs when a shear stress acts on the grain boundary plane and causes the grains to slide. This means that fine-grained materials actually have a poor resistance to creep relative to coarser grains, especially at high temperatures, because smaller grains contain more atoms in grain boundary sites. Grain boundaries also cause deformation in that they are sources and sinks of point defects. Voids in a material tend to gather in a grain boundary, and if this happens to a critical extent, the material could fracture.
During grain boundary migration, the rate determining step depends on the angle between two adjacent grains. In a small angle dislocation boundary, the migration rate depends on vacancy diffusion between dislocations. In a high angle dislocation boundary, this depends on the atom transport by single atom jumps from the shrinking to the growing grains.
Grain boundaries are generally only a few nanometers wide. In common materials, crystallites are large enough that grain boundaries account for a small fraction of the material. However, very small grain sizes are achievable. In nanocrystalline solids, grain boundaries become a significant volume fraction of the material, with profound effects on such properties as diffusion and plasticity. In the limit of small crystallites, as the volume fraction of grain boundaries approaches 100%, the material ceases to have any crystalline character, and thus becomes an amorphous solid.
Grain boundaries are also present in magnetic domains in magnetic materials. A computer hard disk, for example, is made of a hard ferromagnetic material that contains regions of atoms whose magnetic moments can be realigned by an inductive head. The magnetization varies from region to region, and the misalignment between these regions forms boundaries that are key to data storage. The inductive head measures the orientation of the magnetic moments of these domain regions and reads out either a “1” or “0”. These bits are the data being read. Grain size is important in this technology because it limits the number of bits that can fit on one hard disk. The smaller the grain sizes, the more data that can be stored.
Because of the dangers of grain boundaries in certain materials such as superalloy turbine blades, great technological leaps were made to minimize as much as possible the effect of grain boundaries in the blades. The result was directional solidification processing in which grain boundaries were eliminated by producing columnar grain structures aligned parallel to the axis of the blade, since this is usually the direction of maximum tensile stress felt by a blade during its rotation in an airplane. The resulting turbine blades consisted of a single grain, improving reliability. | 0 | Metallurgy |
GenePattern is a powerful scientific workflow system that provides access to hundreds of genomic analysis tools. Use these analysis tools as building blocks to design sophisticated analysis pipelines that capture the methods, parameters, and data used to produce analysis results. Pipelines can be used to create, edit and share reproducible in silico results. | 1 | Gene expression + Signal Transduction |
The usual definition of a splash zone is the area just above and just below the average water level of a body of water. It also includes areas that may be subject to water spray and mist.
A significant amount of corrosion of fences is due to landscaper tools scratching fence coatings and irrigation sprinklers spraying these damaged fences. Recycled water typically has a higher salt content than potable drinking water, meaning that it is more corrosive than regular tap water. The same risk from damage and water spray exists for above ground piping and backflow preventers. Fiberglass covers, cages, and concrete footings have worked well to keep tools at an arms length. Even the location where a roof drain splashes down can matter. Drainage from a homes roof valley can fall directly down onto a gas meter causing its piping to corrode at an accelerated rate reaching 50% wall thickness within 4 years. It is the same effect as a splash zone in the ocean, or in a pool with lot of oxygen and agitation that removes material as it corrodes.
Tanks or structural tubing such as bench seat supports or amusement park rides can accumulate water and moisture if the structure does not allow for drainage. This humid environment can then lead to internal corrosion of the structure affecting the structural integrity. The same can happen in tropical environments leading to external corrosion. This would include Corrosion in ballast tanks on ships. | 0 | Metallurgy |
Wnt signaling and β-catenin dependent gene expression plays a critical role during the formation of different body regions in the early embryo. Experimentally modified embryos that do not express this protein will fail to develop mesoderm and initiate gastrulation.
Early embryos endomesoderm specification also involves the activation of the β-catenin dependent transcripional activity by the first morphogenetic movements of embryogenesis, though mechanotransduction processes. This feature being shared by vertebrate and arthropod bilateria, and by cnidaria, it was proposed to have been evolutionary inherited from its possible involvement in the endomesoderm specification of first metazoa.
During the blastula and gastrula stages, Wnt as well as BMP and FGF pathways will induce the antero-posterior axis formation, regulate the precise placement of the primitive streak (gastrulation and mesoderm formation) as well as the process of neurulation (central nervous system development).
In Xenopus oocytes, β-catenin is initially equally localized to all regions of the egg, but it is targeted for ubiquitination and degradation by the β-catenin destruction complex. Fertilization of the egg causes a rotation of the outer cortical layers, moving clusters of the Frizzled and Dsh proteins closer to the equatorial region. β-catenin will be enriched locally under the influence of Wnt signaling pathway in the cells that inherit this portion of the cytoplasm. It will eventually translocate to the nucleus to bind TCF3 in order to activate several genes that induce dorsal cell characteristics. This signaling results in a region of cells known as the grey crescent, which is a classical organizer of embryonic development. If this region is surgically removed from the embryo, gastrulation does not occur at all. β-Catenin also plays a crucial role in the induction of the blastopore lip, which in turn initiates gastrulation. Inhibition of GSK-3 translation by injection of antisense mRNA may cause a second blastopore and a superfluous body axis to form. A similar effect can result from the overexpression of β-catenin. | 1 | Gene expression + Signal Transduction |
mTOR Complex 2 (mTORC2) is composed of MTOR, rapamycin-insensitive companion of MTOR (RICTOR), MLST8, and mammalian stress-activated protein kinase interacting protein 1 (mSIN1). mTORC2 has been shown to function as an important regulator of the actin cytoskeleton through its stimulation of F-actin stress fibers, paxillin, RhoA, Rac1, Cdc42, and protein kinase C α (PKCα). mTORC2 also phosphorylates the serine/threonine protein kinase Akt/PKB on serine residue Ser473, thus affecting metabolism and survival. Phosphorylation of Akt's serine residue Ser473 by mTORC2 stimulates Akt phosphorylation on threonine residue Thr308 by PDK1 and leads to full Akt activation. In addition, mTORC2 exhibits tyrosine protein kinase activity and phosphorylates the insulin-like growth factor 1 receptor (IGF-1R) and insulin receptor (InsR) on the tyrosine residues Tyr1131/1136 and Tyr1146/1151, respectively, leading to full activation of IGF-IR and InsR. | 1 | Gene expression + Signal Transduction |
The carboxy-terminal domain (CTD) of RNA polymerase II is that portion of the polymerase that is involved in the initiation of DNA transcription, the capping of the RNA transcript, and attachment to the spliceosome for RNA splicing. The CTD typically consists of up to 52 repeats (in humans) of the sequence Tyr-Ser-Pro-Thr-Ser-Pro-Ser. The carboxy-terminal repeat domain (CTD) is essential for life. Cells containing only RNAPII with none or only up to one-third of its repeats are inviable.
The CTD is an extension appended to the C terminus of RPB1, the largest subunit of RNA polymerase II. It serves as a flexible binding scaffold for numerous nuclear factors, determined by the phosphorylation patterns on the CTD repeats. Each repeat contains an evolutionary conserved and repeated heptapeptide, Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7, which is subjected to reversible phosphorylations during each transcription cycle. This domain is inherently unstructured yet evolutionarily conserved, and in eukaryotes it comprises from 25 to 52 tandem copies of the consensus repeat heptad. As the CTD is frequently not required for general transcription factor (GTF)-mediated initiation and RNA synthesis, it does not form a part of the catalytic essence of RNAPII, but performs other functions. | 1 | Gene expression + Signal Transduction |
Diffusional flow is a regime typically below dislocation creep and occurs at high temperatures due to the diffusion of point defects in the material. Diffusional flow can be further broken down into more specific mechanisms: Nabarro–Herring creep, Coble creep, and Harper–Dorn creep.
While most materials will exhibit Nabarro-Herring creep and Coble creep, Harper-Dorn creep is quite rare, having only been reported in a select few materials at low stresses including aluminium, lead, and tin.
The equation for Nabarro-Herring creep is dominated by vacancy diffusion within the lattice, whereas Coble creep is dominated by vacancy diffusion within the grain boundaries. The equation for these mechanisms is shown below where is the applied shear stress, Ω is the atomic volume, k is the Boltzmann constant ,d is the grain size, T is the temperature, and is the effective diffusion coefficient.
The effective diffusion coefficient, = (the volumetric diffusion constant) for Nabarro-Herring creep which dominates at high temperatures, and (where is the grain boundary width and is the diffusion coefficient in the boundary) for Coble creep which dominates at low-temperatures.
From these equations it becomes clear that the boundary between boundary diffusion and lattice diffusion is heavily dependent on grain size. For systems with larger grains, the Nabarro-Herring lattice diffusion region of the deformation mechanism map will be larger than in maps with very small grains. Additionally, the larger the grains, the less diffusional creep and thus the power-law creep region of the map will be larger for large grained materials. Grain boundary engineering is thus an effective strategy to manipulate creep rates. | 0 | Metallurgy |
CcrM (or M.CcrMI) is an orphan DNA methyltransferase, that is involved in controlling gene expression in most Alphaproteobacteria. This enzyme modifies DNA by catalyzing the transference of a methyl group from the S-adenosyl-L methionine substrate to the N6 position of an adenine base in the sequence 5-GANTC-3 with high specificity. In some lineages such as SAR11, the homologous enzymes possess 5-GAWTC-3 specificity. In Caulobacter crescentus Ccrm is produced at the end of the replication cycle when Ccrm recognition sites are hemimethylated, rapidly methylating the DNA. CcrM is essential in other Alphaproteobacteria but its role is not yet determined. CcrM is a highly specific methyltransferase with a novel DNA recognition mechanism. | 1 | Gene expression + Signal Transduction |
Electrical steel is one material that uses decarburization in its production. To prevent the atmospheric gases from reacting with the metal itself, electrical steel is annealed in an atmosphere of nitrogen, hydrogen, and water vapor, where oxidation of the iron is specifically prevented by the proportions of hydrogen and water vapor so that the only reacting substance is carbon being oxidized into carbon monoxide (CO). | 0 | Metallurgy |
A casting defect is an undesired irregularity in a metal casting process. Some defects can be tolerated while others can be repaired, otherwise they must be eliminated. They are broken down into five main categories: gas porosity, shrinkage defects, mould material defects, pouring metal defects, and metallurgical defects. | 0 | Metallurgy |
A regulatory sequence is a segment of a nucleic acid molecule which is capable of increasing or decreasing the expression of specific genes within an organism. Regulation of gene expression is an essential feature of all living organisms and viruses. | 1 | Gene expression + Signal Transduction |
Thermocouples can generally be used in the testing of prototype electrical and mechanical apparatus. For example, switchgear under test for its current carrying capacity may have thermocouples installed and monitored during a heat run test, to confirm that the temperature rise at rated current does not exceed designed limits. | 0 | Metallurgy |
Melt spinning is a metal forming technique that is typically used to form thin ribbons of metal or alloys with a particular atomic structure.
Some important commercial applications of melt-spun metals include high-efficiency transformers (Amorphous metal transformer), sensory devices, telecommunications equipment, and power electronics.
A typical melt spinning process involves casting molten metal by jetting it onto a rotating wheel or drum, which is cooled internally, usually by water or liquid nitrogen. The molten material rapidly solidifies upon contact with the large, cold surface area of the drum. The rotation of the drum constantly removes the solidified product while exposing new surface area to the molten metal stream, allowing for continuous production. The resulting ribbon is then directed along the production line to be packaged or machined into further products.
The cooling rates achievable by melt spinning are on the order of 10–10 Kelvins per second (K/s). Consequently, melt spinning is used to develop materials that require extremely high cooling rates in order to form, such as metallic glasses. Due to their rapid cooling, these products have a highly disordered atomic structure which gives them unique magnetic and physical properties (see amorphous metals).
Several variations to the melt spinning process provide specific advantages. These processes include planar flow casting, twin roll melt spinning, and auto ejection melt spinning.
Originating with Robert Pond in a series of related patents from 1958 to 1961 (US Patent Nos. 2825108, 2910744, and 2976590), the current concept of the melt spinner was outlined by Pond and Maddin in 1969. At first, the liquid was quenched on the inner surface of a drum. Liebermann and Graham further developed the process as a continuous casting technique by 1976, this time on the drum's outer surface. The process can continuously produce thin ribbons of material, with sheets several inches in width commercially available. | 0 | Metallurgy |
Presence of VMAT1 in cells has been shown to protect them from the damaging effects of cooling and rewarming associated with hypothermia. Experiments were carried out on aortic and kidney cells and tissues. Evidence was found that an accumulation of serotonin using VMAT1 and TPH1 allowed for the subsequent release of serotonin when exposed to cold temperatures. This allows cystathionine beta synthase (CBS) mediated generation of HS. The protection against the damage caused by hypothermia is due to a reduction in the generation of reactive oxygen species (ROS), which can induce apoptosis, due to the presence of HS. | 1 | Gene expression + Signal Transduction |
One of the most important results of Wnt signaling and the elevated level of β-catenin in certain cell types is the maintenance of pluripotency. The rate of stem cells in the colon is for instance ensured by such accumulation of β-catenin, which can be stimulated by the Wnt pathway. High frequency peristaltic mechanical strains of the colon are also involved in the β-catenin dependent maintenance of homeostatic levels of colonic stem cells through processes of mechanotransduction. This feature is pathologically enhanced towards tumorigenic hyperproliferation in healthy cells compressed by pressure due genetically altered hyperproliferative tumorous cells.
In other cell types and developmental stages, β-catenin may promote differentiation, especially towards mesodermal cell lineages. | 1 | Gene expression + Signal Transduction |
* Several in-vitro experiments suggest that ISWI remodelers organize nucleosome into proper bundle form and create equal spacing between nucleosomes, whereas SWI/SNF remodelers disorder nucleosomes.
* The ISWI-family remodelers have been shown to play central roles in chromatin assembly after DNA replication and maintenance of higher-order chromatin structures.
* INO80 and SWI/SNF-family remodelers participate in DNA double-strand break (DSB) repair and nucleotide-excision repair (NER) and thereby plays crucial role in TP53 mediated DNA-damage response.
* NuRD/Mi-2/CHD remodeling complexes primarily mediate transcriptional repression in the nucleus and are required for the maintenance of pluripotency of embryonic stem cells. | 1 | Gene expression + Signal Transduction |
Oxidation is the process of an element losing electrons. For example, iron will transfer two of its electrons to oxygen, forming an oxide. This occurs all throughout as an unintended part of the steelmaking process.
Oxygen blowing is a method of steelmaking where oxygen is blown through pig iron to lower the carbon content. Oxygen forms oxides with the unwanted elements, such as carbon, silicon, phosphorus, and manganese, which appear from various stages of the manufacturing process. These oxides will float to the top of the steel pool and remove themselves from the pig iron. However, some of the oxygen will also react with the iron itself.
Due to the high temperatures involved in smelting, oxygen in the air may dissolve into the molten iron while it is being poured. Slag, a byproduct left over after the smelting process, is used to further absorb impurities such as sulfur or oxides and protect steel from further oxidation. However, it can still be responsible for some oxidation.
Some processes, while still able to lead to oxidation, are not relevant to the oxygen content of steel during its manufacture. For example, rust is a red iron oxide that forms when the iron in steel reacts with the oxygen or water in the air. This usually only occurs once the steel has been in use for varying lengths of time. Some physical components of the steelmaking process itself, such as the electric arc furnace, may also wear down and oxidize. This problem is typically dealt with by the use of refractory metals, which resist environmental conditions.
If steel is not properly deoxidized, it will have lost various properties such as tensile strength, ductility, toughness, weldability, polishability, and machinability. This is due to forming non-metallic inclusions and gas pores, bubbles of gas that get trapped during the solidification process of steel. | 0 | Metallurgy |
Some metals, particularly nickel and nickel alloys, can be made into nanocrystalline foils using electrodeposition. | 0 | Metallurgy |
Many commercial elastomers contain polysulfides as crosslinks. These crosslinks interconnect neighboring polymer chains, thereby conferring rigidity. The degree of rigidity is related to the number of crosslinks. Elastomers, therefore, have a characteristic ability to return to their original shape after being stretched or compressed. Because of this memory for their original cured shape, elastomers are commonly referred to as rubbers. The process of crosslinking the polymer chains in these polymers with sulfur is called vulcanization. The sulfur chains attach themselves to the allylic carbon atoms, which are adjacent to C=C linkages. Vulcanization is a step in the processing of several classes of rubbers, including polychloroprene (Neoprene), styrene-butadiene, and polyisoprene, which is chemically similar to natural rubber. Charles Goodyear's discovery of vulcanization, involving the heating of polyisoprene with sulfur, was revolutionary because it converted a sticky and almost useless material into an elastomer that could be fabricated into useful products. | 0 | Metallurgy |
A DNA microarray (also commonly known as DNA chip or biochip) is a collection of microscopic DNA spots attached to a solid surface. Scientists use DNA microarrays to measure the expression levels of large numbers of genes simultaneously or to genotype multiple regions of a genome. Each DNA spot contains picomoles (10 moles) of a specific DNA sequence, known as probes (or reporters or oligos). These can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA (also called anti-sense RNA) sample (called target) under high-stringency conditions. Probe-target hybridization is usually detected and quantified by detection of fluorophore-, silver-, or chemiluminescence-labeled targets to determine relative abundance of nucleic acid sequences in the target. The original nucleic acid arrays were macro arrays approximately 9 cm × 12 cm and the first computerized image based analysis was published in 1981. It was invented by Patrick O. Brown. An example of its application is in SNPs arrays for polymorphisms in cardiovascular diseases, cancer, pathogens and GWAS analysis. It is also used for the identification of structural variations and the measurement of gene expression. | 1 | Gene expression + Signal Transduction |
The sigma-2 receptor (σR) is a sigma receptor subtype that has attracted attention due to its involvement in diseases such as neurological diseases, neurodegenerative, neuro-ophthalmic and cancer. It is currently under investigation for its potential diagnostic and therapeutic uses.
Although the sigma-2 receptor was identified as a separate pharmacological entity from the sigma-1 receptor in 1990, the gene that codes for the receptor was identified as TMEM97 only in 2017. TMEM97 was shown to regulate the cholesterol transporter NPC1 and to be involved in cholesterol homeostasis. The sigma-2 receptor is a four-pass transmembrane protein located in the endoplasmic reticulum. It has been found to play a role in both hormone signaling and calcium signaling, in neuronal signaling, in cell proliferation and death, and in binding of antipsychotics. | 1 | Gene expression + Signal Transduction |
ODS steels creep properties are dependent on the characteristics of the oxide particles in the metal matrix, specifically their ability to prevent dislocation motion as well as the size and distribution of the particles. Hoelzer and coworkers showed that an alloy containing a homogeneous dispersion of 1-5 nm YTiO nanoclusters has superior creep properties to an alloy with a heterogeneous dispersion of 5-20 nm nanoclusters of the same composition.
ODS steels are commonly produced through ball-milling an oxide of interest (e.g. YO, AlO) with pre-alloyed metal powders followed by compression and sintering. It is believed that the oxides enter into solid solution with the metal during ball-milling and subsequently precipitate during the thermal treatment. This process seems simple but many parameters need to be carefully controlled to produce a successful alloy. Leseigneur and coworkers carefully controlled some of these parameters and achieved more consistent and better microstructures. In this two step method the oxide is ball-milled for longer periods to ensure a homogeneous solid solution of the oxide. The powder is annealed at higher temperatures to begin a controlled nucleation of the oxide clusters. Finally the powder is again compressed and sintered to yield the final material. | 0 | Metallurgy |
These processes consist of an annular furnace in which iron ore mixed with coal is circulated. Hot reducing gases flow over, and sometimes through, the charge. The ore is deposited on a tray, or carts, rotating slowly in the furnace. After one rotation, the ore is reduced; it is then discharged and replaced by oxidized ore.
A number of processes have been developed based on this principle. In the 1970s-1980s, the INMETCO process demonstrated only the validity of the idea, with no industrial application. The MAUMEE (or DryIron) process came to fruition in the US with the construction of two small industrial units in the 1990s. Similarly, in Europe, a consortium of Benelux steelmakers developed the COMET process in the laboratory from 1996 to 1998. Despite the consortium's withdrawal from the research program in 1998, a single industrial demonstrator was extrapolated from it, the SIDCOMET, which was discontinued in 2002. RedIron, whose only operational unit was inaugurated in Italy in 2010, also benefits from this research. Japan has adopted the FASTMET process, with the commissioning of three units dedicated to the recovery of iron-rich powders, and is proposing an improved version, the ITmk3 process, with one unit in operation in the United States.
This non-exhaustive list shows that, despite the keen interest shown by steelmakers in developed countries during the 1990s, none of these processes met with commercial success. | 0 | Metallurgy |
In the species Dictyostelium discoideum, cAMP acts outside the cell as a secreted signal. The chemotactic aggregation of cells is organized by periodic waves of cAMP that propagate between cells over distances as large as several centimetres. The waves are the result of a regulated production and secretion of extracellular cAMP and a spontaneous biological oscillator that initiates the waves at centers of territories. | 1 | Gene expression + Signal Transduction |
The ubiquitin-proteasome system (UPS) figures prominently in protein degradation. The 26S proteasome consists of a catalytic subunit (the 20S core particle), and a regulatory subunit (the 19S cap). Poly-ubiquitin chains tag proteins for degradation by the proteasome, which causes hydrolysis of tagged proteins into smaller peptides.
Physiologically, PI31 attacks 20S catalytic domain of 26S Proteasome that results in decreased proteasome activity. (ADP-ribosyl)transferase Tankyrase (TNKS) causes ADP-ribosylation of PI31 which in turn increases the proteasome activity. Inhibition of TNKs further shows the reduced 26S Proteasome assembly. Therefore, ADP-ribosylation promotes 26S Proteasome activity in both Drosophila and human cells. | 1 | Gene expression + Signal Transduction |
The cellular level of β-catenin is mostly controlled by its ubiquitination and proteosomal degradation. The E3 ubiquitin ligase TrCP1 (also known as β-TrCP) can recognize β-catenin as its substrate through a short linear motif on the disordered N-terminus. However, this motif (Asp-Ser-Gly-Ile-His-Ser) of β-catenin needs to be phosphorylated on the two serines in order to be capable to bind β-TrCP. Phosphorylation of the motif is performed by Glycogen Synthase Kinase 3 alpha and beta (GSK3α and GSK3β). GSK3s are constitutively active enzymes implicated in several important regulatory processes. There is one requirement, though: substrates of GSK3 need to be pre-phosphorylated four amino acids downstream (C-terminally) of the actual target site. Thus it also requires a "priming kinase" for its activities. In the case of β-catenin, the most important priming kinase is Casein Kinase I (CKI). Once a serine-threonine rich substrate has been "primed", GSK3 can "walk" across it from C-terminal to N-terminal direction, phosphorylating every 4th serine or threonine residues in a row. This process will result in dual phosphorylation of the aforementioned β-TrCP recognition motif as well. | 1 | Gene expression + Signal Transduction |
In bacteria and eukaryotes, proteins TFIIB and sigma factor are involved in the initiation of transcription, where they facilitate preinitiation complex formation and specific RNA Polymerase-DNA binding. The archaeal counterpart to these two proteins is TFB, which was first identified in the species Pyrococcus woesei in 1992. Since then, research has found that archaeal species must contain at least one copy of TFB to function, although some species may have multiple isoforms in their genome. | 1 | Gene expression + Signal Transduction |
PIK3CA frequently have gain of function mutations in urothelial cancer. Similar to PI3Ka, PI3Kb is expressed in many different cells, and it is mainly involved in the activation of platelets and development of thrombotic diseases. Studies have shown that PI3Kb contribute to tumor proliferation as well. Specifically, it has an important role in tumorigenesis in PTEN-negative cancers. It's reported that interfering with the gene for PI3Kb might be a therapeutic approach for high-risk bladder cancers with mutant PTEN and E-cadherin loss. Specific isoform inhibitors to PI3Kb is a potential treatment for PTEN-deficient cancers. | 1 | Gene expression + Signal Transduction |
TFA interacts with the TBP subunit of TFD and aids in the binding of TBP to TATA-box containing promoter DNA. Interaction of TFA with TBP facilitates formation of and stabilizes the preinitiation complex. Interaction of TFA with TBP also results in the exclusion of negative (repressive) factors that might otherwise bind to TBP and interfere with PIC formation. TFA also acts as a coactivator for some transcriptional activators, assisting with their ability to increase, or activate, transcription. The requirement for TFA in vitro transcription systems has been variable, and it can be considered either as a GTF and/or a loosely associated TAF-like coactivator. Genetic analysis in yeast has shown that TFA is essential for viability. | 1 | Gene expression + Signal Transduction |
The production of an amorphous metal can be achieved by rapidly cooling the liquid alloy to avoid forming a crystal structure. This is traditionally done using melt spinning, which produces a 0.5–125 mm wide strip with a thickness of 20–50 μm. After cooling, the metal can be made into parts or preforms by cutting, stamping, etching, or other methods. | 0 | Metallurgy |
Mutations are modeled as the changes in gene regulation, i.e., the changes of the elements in the regulatory matrix . | 1 | Gene expression + Signal Transduction |
The durability and life of dynamically loaded, welded steel structures is determined in many cases by the welds, in particular the weld transitions. Through selective treatment of the transitions (grinding (abrasive cutting), abrasive blasting, hammering, etc.), the durability of many designs increase significantly. Hammering methods have proven to be particularly effective treatment methods and were within the joint project REFRESH extensively studied and developed. The HiFIT (High-Frequency Impact Treatment (also called HFMI (High Frequency Mechanical Impact))) process is such a hammering method that is universally applicable, requires only a low tech equipment and still offers high reproducibility and the possibility for quality control. | 0 | Metallurgy |
The ETS family is present throughout the body and is involved in a wide variety of functions including the regulation of cellular differentiation, cell cycle control, cell migration, cell proliferation, apoptosis (programmed cell death) and angiogenesis.
Multiple ETS factors have been found to be associated with cancer, such as through gene fusion. For example, the ERG ETS transcription factor is fused to the EWS gene, resulting in a condition called Ewing's sarcoma. The fusion of TEL to the JAK2 protein results in early pre-B acute lymphoid leukaemia. ERG and ETV1 are known gene fusions found in prostate cancer.
In addition, ETS factors, e.g. the vertebrate Etv1 and the invertebrate Ast-1, have been shown to be important players in the specification and differentiation of dopaminergic neurons in both C. elegans and olfactory bulbs of mice. | 1 | Gene expression + Signal Transduction |
In view of its performance, the process seemed a suitable basis for the development of more efficient variants. Around 1940, the Japanese built several small reduction furnaces operating at lower temperatures: one at Tsukiji (1.8 m × 60 m), two at Hachinohe (2 furnaces of 2.8 m × 50 m), and three at Takasago (2 furnaces of 1.83 m × 27 m and 1 furnace of 1.25 m × 17 m). However, since they do not produce Luppen, they cannot be equated with the Krupp-Renn process.
Although direct reduction in a rotary furnace has been the subject of numerous developments, the logical descendant of the Krupp-Renn process is the "Krupp-CODIR process". Developed in the 1970s, it is based on the general principles of the Krupp-Renn process with a lower temperature reduction, typically between 950 and 1,050 °C, which saves fuel but is insufficient to achieve partial melting of the charge. The addition of basic corrective additives (generally limestone or dolomite) mixed with the ore allows the removal of sulfur from the coal, although the thermolysis of these additives is highly endothermic. This process has been adopted by three plants: Dunswart Iron & Steel Works in South Africa in 1973, Sunflag Iron and Steel in 1989, and Goldstar Steel & Alloy in India in 1993. Although the industrial application is now well established, the process has not had the impact of its predecessor.
Finally, there are many post-Krupp-Renn direct reduction processes based on a tubular rotary furnace. At the beginning of the 21st century, their combined output represented between 1% and 2% of world steel production. In 1935 and 1960, the output of the Krupp-Renn process (1 and 2 million tons respectively) represented just under 1% of world steel production. | 0 | Metallurgy |
There are various methodological approaches to archaeometallurgical studies. The same methods used in analytical chemistry may be used to analyze artifacts. Chemical analysis methods may include the analysis of mass, density or chemical composition. Most methods are non-destructive in nature, such as X-ray spectroscopy, or micro-destructive (requiring removal of only a tiny portion of the sample). Non-destructive methods can be used on more artefacts than destructive ones, but because they operate at the surface of the metal, corrosion and other surface effects may interfere with the results. Options that include sampling include various forms of mass spectrometry and a variety of chemical tests. | 0 | Metallurgy |
The number of two-component systems present in a bacterial genome is highly correlated with genome size as well as ecological niche; bacteria that occupy niches with frequent environmental fluctuations possess more histidine kinases and response regulators. New two-component systems may arise by gene duplication or by lateral gene transfer, and the relative rates of each process vary dramatically across bacterial species. In most cases, response regulator genes are located in the same operon as their cognate histidine kinase; lateral gene transfers are more likely to preserve operon structure than gene duplications. The small number of two-component systems present in eukaryotes most likely arose by lateral gene transfer from endosymbiotic organelles; in particular, those present in plants likely derive from chloroplasts. | 1 | Gene expression + Signal Transduction |
Thiosulfate is an acceptable common name (but used almost always); functional replacement IUPAC name is sulfurothioate; the systematic additive IUPAC name is trioxidosulfidosulfate(2−) or trioxido-1κO-disulfate(S—S)(2−). The external sulfur atom has a valence of 2 while the central sulfur atom has a valence of 6. The oxygen atoms have a valence of 2.
Thiosulfate also refers to the esters of thiosulfuric acid, e.g. O,S-dimethyl thiosulfate . Such species are rare. | 0 | Metallurgy |
Although the sequence of steps involved in the assembly of the PIC can vary, in general, they follow step 1, binding to the promoter.
# The TATA-binding protein (TBP, a subunit of TFIID), TBPL1, or TBPL2 can bind the promoter or TATA box. Most genes lack a TATA box and use an initiator element (Inr) or downstream core promoter instead. Nevertheless, TBP is always involved and is forced to bind without sequence specificity. TAFs from TFIID can also be involved when the TATA box is absent. A TFIID TAF will bind sequence specifically, and force the TBP to bind non-sequence specifically, bringing the remaining portions of TFIID to the promoter.
# TFIIA interacts with the TBP subunit of TFIID and aids in the binding of TBP to TATA-box containing promoter DNA. Although TFIIA does not recognize DNA itself, its interactions with TBP allow it to stabilize and facilitate formation of the PIC.
# The N-terminal domain of TFIIB brings the DNA into proper position for entry into the active site of RNA polymerase II. TFIIB binds partially sequence specifically, with some preference for BRE. The TFIID-TFIIA-TFIIB (DAB)-promoter complex subsequently recruits RNA polymerase II and TFIIF.
# TFIIF (two subunits, RAP30 and RAP74, showing some similarity to bacterial sigma factors) and Pol II enter the complex together. TFIIF helps to speed up the polymerization process.
# TFIIE joins the growing complex and recruits TFIIH. TFIIE may be involved in DNA melting at the promoter: it contains a zinc ribbon motif that can bind single-stranded DNA. TFIIE helps to open and close the Pol II’s Jaw-like structure, which enables movement down the DNA strand.
# DNA may be wrapped one complete turn around the preinitiation complex and it is TFIIF that helps keep this tight wrapping. In the process, the torsional strain on the DNA may aid in DNA melting at the promoter, forming the transcription bubble.
# TFIIH enters the complex. TFIIH is a large protein complex that contains among others the CDK7/cyclin H kinase complex and a DNA helicase. TFIIH has three functions: It binds specifically to the template strand to ensure that the correct strand of DNA is transcribed and melts or unwinds the DNA (ATP-dependent) to separate the two strands using its helicase activity. It has a kinase activity that phosphorylates the C-terminal domain (CTD) of Pol II at the amino acid serine. This switches the RNA polymerase to start producing RNA. Finally it is essential for Nucleotide Excision Repair (NER) of damaged DNA. TFIIH and TFIIE strongly interact with one another. TFIIE affects TFIIH's catalytic activity. Without TFIIE, TFIIH will not unwind the promoter.
# TFIIH helps create the transcription bubble and may be required for transcription if the DNA template is not already denatured or if it is supercoiled.
# Mediator then encases all the transcription factors and Pol II. It interacts with enhancers, areas very far away (upstream or downstream) that help regulate transcription.
The formation of the preinitiation complex (PIC) is analogous to the mechanism seen in bacterial initiation. In bacteria, the sigma factor recognizes and binds to the promoter sequence. In eukaryotes, the transcription factors perform this role. | 1 | Gene expression + Signal Transduction |
The bowl and stand were favourite archaic forms. The Greek stand was a fusion of the cast-rod tripod and the embossed cone. Some early examples have large triangular plates between the legs, worked in relief; but the developed type has separate legs and stays of which the joints are masked with decorative rims and feet and covering-plates. These ornaments are cast and chased, and are modelled in floral, animal and human forms. The feet are lions' paws, which sometimes clasp a ball or stands on toads; the rims and plaques bear groups of fighting animals, warriors, revelles or athletes, nymphs and satyrs, or mythological subjects in relief. Feasters recline and horsemen gallop on the rims of bowls; handles are formed by single standing figures, arched pairs of wrestlers, lovers holding hands, or two vertical soldiers carrying a horizontal comrade. Nude athletes serve as handles for all kinds of lids and vessels, draped women support mirror-disks around which love-gods fly, and similar figures crown tall shafts of candelabra. Handle-bases are modelled as satyr-masks, palmettes and sphinxes. This is Greek ornament of the 6th and later centuries. Its centres of manufacture are not precisely known, but the style of much archaic work points to Ionia.
Etruscan fabrics approach their Greek originals so closely that it is not possible to separate them in technique or design, and the Etruscan style is no more than provincial Greek. Bronze was quite plentiful in Italy, the earliest Roman coinage was of heavy bronze, and there is literary evidence that Etruscan bronzes were exported. The process of line engraving seems to have been a Latin speciality; it was applied in pictorial subjects on the backs of mirrors and on the sides large cylindrical boxes, both of which are particularly connected with Praeneste. The finest of all such boxes, the Firconi cista in the Villa Giulia at Rome, bears the signature of a Roman artist. These belong to the 4th and 3rd centuries BC. Greek mirrors of the same period are seldom engraved; the disk is usually contained in a flat box which has a repoussé design on its lid. | 0 | Metallurgy |
Sepro designs and builds modular and mobile processing plants for a wide range of mineral applications. Complete plants can be assembled using Sepro manufactured equipment along with equipment from third-party vendors and sub-contractors.
Sepro Mobile Plants are designed to be easily re-locatable as they are mounted on road transportable custom built trailer assemblies. These include the Sepro Mobile Mill Plant and Sepro Mobile Flotation Plant, both of which were installed by Banks Island Gold Ltd at the company's Yellow Giant Gold Property on the coast of British Columbia. They can be designed to encompass a wide variety of process options from crushing through to the final concentrate collection.
Sepro Modular and Skid Mounted Plants are engineered around structural elements that are simple and easy to erect on site. These plants can be designed with larger equipment for higher tonnage applications than that of the Sepro Mobile Plants. One example is a 360 TPD Gold Processing Plant Sepro supplied to ProEurasia LCC for the Vladimirskaya Project in Russia. This included milling, gravity and smelting circuits.
Sepro also offers standard process modules which are designed around a single recovery or procession option. Dense Media Separation and Gravity Concentration are two examples of standard Sepro process modules. | 0 | Metallurgy |
PKR (encoded in humans by the gene EIF2AK2) activation is mainly dependent on the presence of double-stranded RNA during a viral infection. dsRNA causes PKR to form dimers, resulting in autophosphorylation and activation. Once activated, PKR will phosphorylate eIF2α which causes a cascade of events that result in viral and host protein synthesis being inhibited. Other stressors that cause the activation of PKR include oxidative stress, endoplasmic reticulum stress, growth factor deprivation and bacterial infection. Caspase activity early on in apoptosis has also been observed to trigger activation of PKR. However, these stressors differ in that they activate PKR without using dsRNA. | 1 | Gene expression + Signal Transduction |
Rosin fluxes are categorized by grades of activity: L for low, M for moderate, and H for high. There are also other abbreviations for different rosin flux grades:
* R (Rosin) – pure rosin, no activators, low activity, mildest
* WW (water-white) – purest rosin grade, no activators, low activity, sometimes synonymous with R
* RMA (rosin mildly activated) - contains mild activators, typically no halides
* RA (rosin activated) – rosin with strong activators, high activity, contains halides
* OA (organic acid) – rosin activated with organic acids, high activity, highly corrosive, aqueous cleaning
* SA (synthetically activated) – rosin with strong synthetic activators, high activity; formulated to be easily soluble in organic solvents (chlorofluorocarbons, alcohols) to facilitate cleaning
* WS (water-soluble) – usually based on inorganic or organic halides; highly corrosive residues
* SRA (superactivated rosin) – rosin with very strong activators, very high activity
* IA (inorganic acid) – rosin activated with inorganic acids (usually hydrochloric acid or phosphoric acid), highest activities, highly corrosive
R, WW, and RMA grades are used for joints that can not be easily cleaned or where there is too high corrosion risk. More active grades require thorough cleaning of the residues. Improper cleaning can actually aggravate the corrosion by releasing trapped activators from the flux residues. | 0 | Metallurgy |
TCF4 proteins act as transcription factors which will bind to the immunoglobulin enhancer mu-E5/kappa-E2 motif. TCF4 activates transcription by binding to the E-box (5’-CANNTG-3’) found usually on SSTR2-INR, or somatostatin receptor 2 initiator element. TCF4 is primarily involved in neurological development of the fetus during pregnancy by initiating neural differentiation by binding to DNA. It is found in the central nervous system, somites, and gonadal ridge during early development. Later in development it will be found in the thyroid, thymus, and kidneys while in adulthood TCF4 it is found in lymphocytes, muscles, mature neurons, and gastrointestinal system. | 1 | Gene expression + Signal Transduction |
* Casting – molten metal is poured into a shaped mold. Variants of casting include sand casting, investment casting, also called the lost wax process, die casting, and continuous castings. Each of these forms has advantages for certain metals and applications considering factors like magnetism and corrosion.
* Forging – a red-hot billet is hammered into shape.
* Rolling – a billet is passed through successively narrower rollers to create a sheet.
* Extrusion – a hot and malleable metal is forced under pressure through a die, which shapes it before it cools.
* Machining – lathes, milling machines and drills cut the cold metal to shape.
* Sintering – a powdered metal is heated in a non-oxidizing environment after being compressed into a die.
* Fabrication – sheets of metal are cut with guillotines or gas cutters and bent and welded into structural shape.
* Laser cladding – metallic powder is blown through a movable laser beam (e.g. mounted on a NC 5-axis machine). The resulting melted metal reaches a substrate to form a melt pool. By moving the laser head, it is possible to stack the tracks and build up a three-dimensional piece.
* 3D printing – Sintering or melting amorphous powder metal in a 3D space to make any object to shape.
Cold-working processes, in which the product's shape is altered by rolling, fabrication or other processes, while the product is cold, can increase the strength of the product by a process called work hardening. Work hardening creates microscopic defects in the metal, which resist further changes of shape. | 0 | Metallurgy |
A splice site is the border between an exon and intron in a gene. These sites contain a particular sequence motif, which is necessary for recognition and processing by the RNA splicing machinery.
The S&S algorithm uses sliding windows of eight nucleotides, corresponding to the length of the splice site sequence motif, to identify these conserved sequences and thus potential splice sites. Using a weighted table of nucleotide frequencies, the S&S algorithm outputs a consensus-based percentage for the possibility of the window containing a splice site.
The S&S algorithm serves as the basis of other software tools, such as Human Splicing Finder, Splice-site Analyzer Tool, dbass (Ensembl), Alamut, and SROOGLE. | 1 | Gene expression + Signal Transduction |
This book covers underground mining and surveying. When a vein below ground is to be exploited a shaft is begun and a wooden shed with a windlass is placed above it. The tunnel dug at the bottom follows the vein and is just big enough for a man. The entire vein should be removed. Sometimes the tunnel eventually connects with a tunnel mouth in a hill side. Stringers and cross veins should be explored with cross tunnels or shafts when they occur. Agricola next describes that gold, silver, copper and mercury can be found as native metals, the others very rarely. Gold and silver ores are described in detail. Agricola then states that it is rarely worthwhile digging for other metals unless the ores are rich. Gems are found in some mines, but rarely have their own veins, lodestone is found in iron mines and emery in silver mines. Various minerals and colours of earths can be used to give indications of the presence of metal ores. The actual mineworking varies with the hardness of the rock, the softest is worked with a pick and requires shoring with wood, the hardest is usually broken with fire. Iron wedges, hammers and crowbars are used to break other rocks. Noxious gases and the ingress of water are described. Methods for lining tunnels and shafts with timber are described. The book concludes with a long treatise on surveying, showing the instruments required and techniques for determining the course of veins and tunnels. Surveyors allow veins to be followed, but also prevent mines removing ore from other claims and stop mine workings from breaking into other workings. | 0 | Metallurgy |
Brass was used in Lothal and Atranjikhera in the 3rd and 2nd millennium BCE. Brass and probably zinc was also found at Taxila in 4th to 3rd century BCE contexts. | 0 | Metallurgy |
Vacuum deoxidation is a method which involves using a vacuum to remove impurities. A portion of the carbon and oxygen in steel will react, forming carbon monoxide. CO gas will float up to the top of the liquid steel and be removed by a vacuum system.
As the chemical reaction involved in vacuum deoxidation is:
the reaction between carbon and oxygen is represented by the following chemical equilibrium equation:
where P is the partial pressure of the carbon monoxide formed.
Decreasing the oxygen activity(a) will result in a higher equilibrium constant, thus more product, CO. To achieve this, subjecting the pool of steel to vacuum treatment decreases the value of P, allowing for more CO gas to be produced. | 0 | Metallurgy |
KAP1 can regulate genomic transcription through a variety of mechanisms, many of which remain somewhat unclear. Studies have shown that KAP1 can repress transcription by binding directly to the genome (which can be sufficient in and of itself) or through the induction of heterochromatin formation via the Mi2α-SETB1-HP1 macromolecular complex. KAP1 can also interact with histone methyltransferases and deacetylases via the C-terminal PHD and Bromodomain to control transcription epigenetically. | 1 | Gene expression + Signal Transduction |
Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen atoms. Note that molecular gaseous hydrogen does not have the same effect as atoms or ions released into solid solution in the metal. | 0 | Metallurgy |
Epinephrine and glucagon affect the activity of protein kinase A by changing the levels of cAMP in a cell via the G-protein mechanism, using adenylate cyclase. Protein kinase A acts to phosphorylate many enzymes important in metabolism. For example, protein kinase A phosphorylates acetyl-CoA carboxylase and pyruvate dehydrogenase. Such covalent modification has an inhibitory effect on these enzymes, thus inhibiting lipogenesis and promoting net gluconeogenesis. Insulin, on the other hand, decreases the level of phosphorylation of these enzymes, which instead promotes lipogenesis. Recall that gluconeogenesis does not occur in myocytes. | 1 | Gene expression + Signal Transduction |
Some patients with ovarian hyperstimulation syndrome may have mutations in the gene for FSHR, making them more sensitive to gonadotropin stimulation.
Women with 46 XX gonadal dysgenesis experience primary amenorrhea with hypergonadotropic hypogonadism. There are forms of 46 xx gonadal dysgenesis wherein abnormalities in the FSH-receptor have been reported and are thought to be the cause of the hypogonadism.
Polymorphism may affect FSH receptor populations and lead to poorer responses in infertile women receiving FSH medication for IVF.
Alternative splicing of the FSHR gene may be implicated in subfertility in males | 1 | Gene expression + Signal Transduction |
It is important to recognize that while iron production had great influence over Africa both culturally in trade and expansion (Martinelli, 1993, 1996, 2004), as well as socially in beliefs and rituals, there is great regional variation. Much of the evidence for cultural significance comes from the practises still carried out today by different African cultures. Ethnographical information has been very useful in reconstructing the events surrounding iron production in the past, however the reconstructions could have become distorted through time and influence by anthropologist's studies.
The control of iron production was often by ironworkers themselves, or a "central power" in larger societies such as kingdoms or states (Barros 2000, p. 154). The demand for trade is believed to have resulted in some societies working only as smelters or smiths, specialising in just one of the many skills necessary to the production process. It is possible that this also led to tradesmen specialising in transporting and trading iron (Barros 2000, pg152). However, not every region benefited from industrialising iron production, others created environmental problems that arose due to the massive deforestation required to provide the charcoal for fuelling furnaces (for example the ecological crisis of the Mema Region (Holl 2000, pg48)).
Iron smelters and smiths received different social status depending on their culture. Some were lower in society due to the aspect of manual labour and associations with witchcraft, for example in the Maasai and Tuareg (Childs et al. 2005 pg 288). In other cultures the skills are often passed down through family and would receive great social status (sometimes even considered as witchdoctors) within their community. Their powerful knowledge allowed them to produce materials on which the whole community relied. In some communities they were believed to have such strong supernatural powers that they were regarded as highly as the king or chief. For example, an excavation at the royal tomb of King Rugira (Great Lakes, Eastern Africa) found two iron anvils placed at his head (Childs et al. 2005, p. 288 in Herbert 1993:ch.6). In some cultures mythical stories have been built around the premise of the iron smelter emphasising their godlike significance. | 0 | Metallurgy |