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Surface integrity is the surface condition of a workpiece after being modified by a manufacturing process. The term was coined by Michael Field and John F. Kahles in 1964.
The surface integrity of a workpiece or item changes the material's properties. The consequences of changes to surface integrity are a mechanical engineering design problem, but the preservation of those properties are a manufacturing consideration.
Surface integrity can have a great impact on a parts function; for example, Inconel 718 can have a fatigue limit as high as after a gentle grinding or as low as after electrical discharge machining (EDM). | 0 | Metallurgy |
Homologous desensitization occurs when a receptor decreases its response to an agonist at high concentration. It is a process through which, after prolonged agonist exposure, the receptor is uncoupled from its signaling cascade and thus the cellular effect of receptor activation is attenuated.
Homologous desensitization is distinguished from heterologous desensitization, a process in which repeated stimulation of a receptor by an agonist results in desensitization of the stimulated receptor as well as other, usually inactive, receptors on the same cell. They are sometimes denoted as agonist-dependent and agonist-independent desensitization respectively. While heterologous desensitization occurs rapidly at low agonist concentrations, homologous desensitization shows a dose dependent response and usually begins at significantly higher concentrations.
Homologous desensitization serves as a mechanism for tachyphylaxis and helps organisms to maintain homeostasis. The process of homologous desensitization has been extensively studied utilizing G protein–coupled receptors (GPCRs). While the different mechanisms for desensitization are still being characterized, there are currently four known mechanisms: uncoupling of receptors from associated G proteins, endocytosis, degradation, and downregulation. The degradation and downregulation of receptors is often also associated with drug tolerance since it has a longer onset, from hours to days. It has been shown that these mechanisms can happen independently of one another, but that they also influence one another. In addition, the same receptor expressed in different cell types can be desensitized by different mechanisms. | 1 | Gene expression + Signal Transduction |
Grain refinement, also known as inoculation, is the set of techniques used to implement grain boundary strengthening in metallurgy. The specific techniques and corresponding mechanisms will vary based on what materials are being considered.
One method for controlling grain size in aluminum alloys is by introducing particles to serve as nucleants, such as Al–5%Ti. Grains will grow via heterogeneous nucleation; that is, for a given degree of undercooling beneath the melting temperature, aluminum particles in the melt will nucleate on the surface of the added particles. Grains will grow in the form of dendrites growing radially away from the surface of the nucleant. Solute particles can then be added (called grain refiners) which limit the growth of dendrites, leading to grain refinement. Al-Ti-B alloys are the most common grain refiner for Al alloys; however, novel refiners such as AlSc have been suggested.
One common technique is to induce a very small fraction of the melt to solidify at a much higher temperature than the rest; this will generate seed crystals that act as a template when the rest of the material falls to its (lower) melting temperature and begins to solidify. Since a huge number of minuscule seed crystals are present, a nearly equal number of crystallites result, and the size of any one grain is limited. | 0 | Metallurgy |
Ultrasonic impact treatment (UIT) is a metallurgical processing technique, similar to work hardening, in which ultrasonic energy is applied to a metal object. This technique is part of the High Frequency Mechanical Impact (HFMI) processes. Other acronyms are also equivalent: Ultrasonic Needle Peening (UNP), Ultrasonic Peening (UP). Ultrasonic impact treatment can result in controlled residual compressive stress, grain refinement and grain size reduction. Low and high cycle fatigue are enhanced and have been documented to provide increases up to ten times greater than non-UIT specimens. | 0 | Metallurgy |
The bacterial natural product rapamycin or sirolimus, a cytostatic agent, has been used in combination therapy with corticosteroids and cyclosporine in patients who received kidney transplantation to prevent organ rejection both in the US and Europe, due to its unsatisfying pharmacokinetic properties. In 2003, the U.S. Food and Drug Administration approved sirolimus-eluting coronary stents, which are used in patients with narrowing of coronary arteries, or so-called atherosclerosis.
Recently rapamycin has shown effective in the inhibition of growth of several human cancers and murine cell lines. Rapamycin is the main mTOR inhibitor, but deforolimus (AP23573), everolimus (RAD001), and temsirolimus (CCI-779), are the newly developed rapamycin analogs. | 1 | Gene expression + Signal Transduction |
The hallmark difference of elongation in eukaryotes in comparison to prokaryotes is its separation from transcription. While prokaryotes are able to undergo both cellular processes simultaneously, the spatial separation that is provided by the nuclear membrane prevents this coupling in eukaryotes. Eukaryotic elongation factor 2 (eEF2) is a regulateable GTP-dependent translocase that moves nascent polypeptide chains from the A-site to the P-site in the ribosome. Phosphorylation of threonine 56 is inhibitory to the binding of eEF2 to the ribosome. Cellular stressors, such as anoxia have proven to induce translational inhibition through this biochemical interaction. | 1 | Gene expression + Signal Transduction |
For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For calcium labeling purposes 100% of the Daily Value was 1000 mg, but as of May 27, 2016 it was revised to 1300 mg to bring it into agreement with the RDA. A table of the old and new adult daily values is provided at Reference Daily Intake. | 1 | Gene expression + Signal Transduction |
Basic oxygen steelmaking (BOS, BOP, BOF, or OSM), also known as Linz-Donawitz steelmaking or the oxygen converter process, is a method of primary steelmaking in which carbon-rich molten pig iron is made into steel. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into low-carbon steel. The process is known as basic because fluxes of burnt lime or dolomite, which are chemical bases, are added to promote the removal of impurities and protect the lining of the converter.
The process was invented in 1948 by Swiss engineer Robert Durrer and commercialized in 1952–1953 by the Austrian steelmaking company VOEST and ÖAMG. The LD converter, named after the Austrian towns Linz and Donawitz (a district of Leoben) is a refined version of the Bessemer converter where blowing of air is replaced with blowing oxygen. It reduced capital cost of the plants and smelting time, and increased labor productivity. Between 1920 and 2000, labor requirements in the industry decreased by a factor of 1,000, from more than 3 man-hours per metric ton to just 0.003. The majority of steel manufactured in the world is produced using the basic oxygen furnace. In 2000, it accounted for 60% of global steel output.
Modern furnaces will take a charge of iron of up to 400 tons and convert it into steel in less than 40 minutes, compared to 10–12 hours in an open hearth furnace. | 0 | Metallurgy |
Tank leaching is usually differentiated from vat leaching on the following factors:
# In tank leaching the material is ground sufficiently fine to form a slurry or pulp, which can flow under gravity or when pumped. In vat leaching typically a coarser material is placed in the vat for leaching, this reduces the cost of size reduction;
# Tanks are typically equipped with agitators, baffles, gas introduction equipment designed to maintain the solids in suspension in the slurry, and achieve leaching. Vats usually do not contain much internal equipment, except for agitators.
# Tank leaching is typically continuous, while vat leaching is operated in a batch fashion, this is not always the case, and commercial processes using continuous vat leaching have been tested;
# Typically the retention time required for vat leaching is more than that for tank leaching to achieve the same percentage of recovery of the valuable material being leached;
In a tank leach the slurry is moved, while in a vat leach the solids remain in the vat, and solution is moved. | 0 | Metallurgy |
Iron levels in cells are maintained by translation regulation of many proteins involved in iron storage and metabolism. The 5′ UTR has the ability to form a hairpin loop secondary structure (known as the iron response element or IRE) that is recognized by iron-regulatory proteins (IRP1 and IRP2). In low levels of iron, the ORF of the target mRNA is blocked as a result of steric hindrance from the binding of IRP1 and IRP2 to the IRE. When iron is high, then the two iron-regulatory proteins do not bind as strongly and allow proteins to be expressed that have a role in iron concentration control. This function has gained some interest after it was revealed that the translation of amyloid precursor protein may be disrupted due to a single-nucleotide polymorphism to the IRE found in the 5′ UTR of its mRNA, leading to a spontaneous increased risk of Alzheimer's disease. | 1 | Gene expression + Signal Transduction |
PAF is a potent activator of platelet aggregation, inflammation, and anaphylaxis. It is similar to the ubiquitous membrane phospholipid phosphatidylcholine except that it contains an acetyl-group in the SN-2 position and the SN-1 position contains an ether-linkage. PAF signals through a dedicated G-protein coupled receptor, PAFR and is inactivated by PAF acetylhydrolase. | 1 | Gene expression + Signal Transduction |
Metallography is the study of the physical structure and components of metals, by using microscopy.
Ceramic and polymeric materials may also be prepared using metallographic techniques, hence the terms ceramography, plastography and, collectively, materialography. | 0 | Metallurgy |
The presence of nitrogen activates the csiR gene located downstream of the gabP gene. The csiR gene encodes a protein that acts as a transcriptional repressor for csiD-ygaF-gab operon hence shutting off the GABA degradation pathway. | 1 | Gene expression + Signal Transduction |
Fas forms the death-inducing signaling complex (DISC) upon ligand binding. Membrane-anchored Fas ligand trimer on the surface of an adjacent cell causes oligomerization of Fas.
Recent studies which suggested the trimerization of Fas could not be validated. Other models suggested the oligomerization up to 5–7 Fas molecules in the DISC.
This event is also mimicked by binding of an agonistic Fas antibody, though some evidence suggests that the apoptotic signal induced by the antibody is unreliable in the study of Fas signaling. To this end, several clever ways of trimerizing the antibody for in vitro research have been employed.
Upon ensuing death domain (DD) aggregation, the receptor complex is internalized via the cellular endosomal machinery. This allows the adaptor molecule FADD to bind the death domain of Fas through its own death domain.
FADD also contains a death effector domain (DED) near its amino terminus, which facilitates binding to the DED of FADD-like interleukin-1 beta-converting enzyme (FLICE), more commonly referred to as caspase-8. FLICE can then self-activate through proteolytic cleavage into p10 and p18 subunits, two each of which form the active heterotetramer enzyme. Active caspase-8 is then released from the DISC into the cytosol, where it cleaves other effector caspases, eventually leading to DNA degradation, membrane blebbing, and other hallmarks of apoptosis.
Recently, Fas has also been shown to promote tumor growth, since during tumor progression, it is frequently downregulated or cells are rendered apoptosis resistant. Cancer cells in general, regardless of their Fas apoptosis sensitivity, depend on constitutive activity of Fas. This is stimulated by cancer-produced Fas ligand for optimal growth.
Although Fas has been shown to promote tumor growth in the above mouse models, analysis of the human cancer genomics database revealed that FAS is not significantly focally amplified across a dataset of 3131 tumors (FAS is not an oncogene), but is significantly focally deleted across the entire dataset of these 3131 tumors, suggesting that FAS functions as a tumor suppressor in humans.
In cultured cells, FasL induces various types of cancer cell apoptosis through the Fas receptor. In AOM-DSS-induced colon carcinoma and MCA-induced sarcoma mouse models, it has been shown that Fas acts as a tumor suppressor. Furthermore, the Fas receptor also mediates tumor-specific cytotoxic T lymphocyte (CTL) anti-tumor cytotoxicity. In addition to the well-described on-target CTL anti-tumor cytotoxicity, Fas has been ascribed with a distinct function – the induction of bystander tumor cell death even amongst cognate antigen non-expressing (bystander) cells. CTL-mediated bystander killing was described by the Fleischer Lab in 1986 and later attributed to fas-mediated lysis in vitro by the Austin Research Institute, Cellular Cytotoxicity Laboratory. More recently, fas-mediated bystander tumor cell killing was demonstrated in vivo by the Lymphoma Immunotherapy Program at Mount Sinai School of Medicine using T cells and CAR-T cells, similar to additional in vitro work using bispecific antibodies performed at Amgen. | 1 | Gene expression + Signal Transduction |
The binding and cyclizing of adenosine 5’ triphosphate (ATP) to the catalytic active site of the enzyme is coordinated by two metal cations. The catalytic activity of sAC is increase by the presence of manganese [Mn]. sAC magnesium [Mg] activity is regulated by calcium [Ca] which increases the affinity for ATP of mammalian sAC. In addition, bicarbonate [HCO] releases ATP-Mg substrate inhibition and increases V of the enzyme.
The open conformation state of sAC is reached when ATP, with Ca bound to its γ-phosphate binds with specific residues in the catalytic center of the enzyme. When the second metal – a Mg ion – binds to the α-phosphate of ATP leads to a conformational change of the enzyme: the close state. The change in conformation from open to close state induces esterification of the α-phosphate with the ribose in adenosine and the release of the β- and γ-phosphates, this leads to cyclizing. Hydrogencarbonate stimulates the enzyme’s V by promoting the allosteric change that leads to active site closure, recruitment of the catalytic Mg ion, and readjustment of the phosphates in the bound ATP. The activator bicarbonate binds to a site pseudo-symmetric to the active site and triggers conformational changes by recruiting Arg176 from the active site (see above - "structure"). Calcium increases substrate affinity by replacing the magnesium in the ion B site, which provides an anchoring point for the beta- and gamma-phosphates of the ATP substrate. | 1 | Gene expression + Signal Transduction |
Reverse transfection is a technique for the transfer of genetic material into cells. As DNA is printed on a glass slide for the transfection process (the deliberate introduction of nucleic acids into cells) to occur before the addition of adherent cells, the order of addition of DNA and adherent cells is reverse that of conventional transfection. Hence, the word “reverse” is used. | 1 | Gene expression + Signal Transduction |
The development of resistance to chemotherapies such as paclitaxel and cisplatin in non-small-cell lung cancer (NSCLC) is strongly associated with overexpression of beta III tubulin. Investigations by the Children's Cancer Institute Australia (University of NSW, Lowy Cancer Research Centre) demonstrated that beta III-tubulin knockdown by DDRNAI delayed tumor growth and increased chemosensitivity in mouse models.
Tributarna is a triple DNA cassette expressing three shRNA molecules each of which separately targets beta III tubulin and strongly inhibits its expression. Studies in an orthotopic-mouse model, where the construct is delivered by a modified polyethylenimine vector, jetPEI, that targets lung tissue are in progress. | 1 | Gene expression + Signal Transduction |
The identification of MEKK1-MKK1/2-MPK4 in pathogen signaling has been a tremendous finding. Mekk1, mkk1/mkk2 double and mpk4 mutations are dwarfed and acquire too much of reactive oxygen species. The mutations are considered to be from the enhancement of SA levels, which is partially reversed by bacterial SA hydrolase. Mekk1, mkk1/mkk2 double and mpk4 mutations have cell death occur spontaneously, pathogenesis-related genes and increased resistance to pathogens. MEKK1 appears to have deregulation pathways that are unknown and do not involve MKK1/MKK2 nor MPK4. MEKK1 interact with WRKY53, which is responsible for mekk1 genes set, and alter the activity of WRKY53 that is a short portion of MAPK signaling. Substrates of MPK4 are three proteins: WRKY33, WRKY25, and MKS1. Ternary MKS1-MPK4-WRKY33 complexes have been recognized by nuclear extracts. Recruitment of WRKY33 depends on the phosphorylation of MPK4. Once activated, MPK3 phosphorylates MKS1, which releases WRKY33 from the ternary complex. The free WRKY33 is believed to induce transcription on target genes., allowing for a negative regulation by MPK4. Pathogens have developed mechanisms that inactivate PAMP-induced signaling pathways through the MAPK networks. Andrea Pitzschke and her colleges claim “AvrPto and AvrPtoB interact with the FLS2 receptor and its co-receptor BAK1. AvrPtoB catalyzes the polyubiquitination and subsequent proteasome-dependent degradation of FLS2” (Pitzschke 3). AvrPto interacts with BAK1 and interrupts the binding of FLS2. Pseudomonas syringae have HopAI1, which is a phosphothreonin lyase, and dephosphorylates the threonine residue at the upstream MAPKKs. HopAI1 interacts with MPK3 and MPK6 allowing for flg22 activation to occur. In certain soil-borne pathogens that carry flagellin variants cannot be detected by FLS2, but there is still a triggered innate immune response. The immune response has been shown to be from the EF-Tu protein. Flg22, elf18, FLS2 and EFR have receptors that are in the same subfamily of LRR-RLKs, LRRXII. This means that elf18 and flg22 induce extracellular alkalization, rapid activation of MAPKs, and gene responses that are similar to each other. Although there appears to be an important relationship between MAPKs with EF-Tu-triggered defense, the evidence remains to be unclear. The reason for this unclear relationship is because of Agrobacterium tumefaciens, which infects into segments of plant DNA. EFR1 mutants do not recognize EF-Tu, but there is no research on MAPK activities and efr1. Initiation of defense signaling can be a positive effect to the plant pathogens because activating MPK3 in response to flg22 causes phosphorylation and translocation of virE2 interacting protein 1 (VIP1). VIP1 serves as a shuttle for the pathogenic T-DNA, but the induction of defense genes can occur as well. This allows for the spreading and cessation of the pathogen in the plant, but the pathogen can overcome the problem by attacking VIP1 for proteasome degradation by VirF, which is a virulence factor that encodes an F-box protein. | 1 | Gene expression + Signal Transduction |
The follicle-stimulating hormone receptor or FSH receptor (FSHR) is a transmembrane receptor that interacts with the follicle-stimulating hormone (FSH) and represents a G protein-coupled receptor (GPCR). Its activation is necessary for the hormonal functioning of FSH. FSHRs are found in the ovary, testis, and uterus. | 1 | Gene expression + Signal Transduction |
Copper concentrates produced by mines are sold to smelters and refiners who treat the ore and refine the copper and charge for this service via treatment charges (TCs) and refining charges (RCs). The TCs are charged in US$ per tonne of concentrate treated and RCs are charged in cents per pound treated, denominated in US dollars, with benchmark prices set annually by major Japanese smelters. The customer in this case can be a smelter, who on-sells blister copper ingots to a refiner, or a smelter-refiner which is vertically integrated.
One prevalent form of copper concentrate contains gold and silver, like the one produced by Bougainville Copper Limited from the Panguna mine from the early 1970s to the late 1980s.
The typical contract for a miner is denominated against the London Metal Exchange price, minus the TC-RCs and any applicable penalties or credits. Penalties may be assessed against copper concentrates according to the level of deleterious elements such as arsenic, bismuth, lead or tungsten. Because a large portion of copper sulfide ore bodies contain silver or gold in appreciable amounts, a credit can be paid to the miner for these metals if their concentration within the concentrate is above a certain amount. Usually the refiner or smelter charges the miner a fee based on the concentration; a typical contract will specify that a credit is due for every ounce of the metal in the concentrate above a certain concentration; below that, if it is recovered, the smelter will keep the metal and sell it to defray costs.
Copper concentrate is traded either via spot contracts or under long term contracts as an intermediate product in its own right. Often the smelter sells the copper metal itself on behalf of the miner. The miner is paid the price at the time that the smelter-refiner makes the sale, not at the price on the date of delivery of the concentrate. Under a Quotational Pricing system, the price is agreed to be at a fixed date in the future, typically 90 days from time of delivery to the smelter.
A-grade copper cathode is of 99.99% copper in sheets that are 1 cm thick, and approximately 1 meter square weighing approximately 200 pounds. It is a true commodity, deliverable to and tradeable upon the metal exchanges in New York City (COMEX), London (London Metals Exchange) and Shanghai (Shanghai Futures Exchange). Often copper cathode is traded upon the exchanges indirectly via warrants, options, or swap contracts such that the majority of copper is traded upon the LME/COMEX/SFE, but delivery is achieved directly, logistically moving the physical copper, and transferring the copper sheet from the physical warehouses themselves.
The chemical specification for electrolytic grade copper is ASTM B 115-00 (a standard that specifies the purity and maximum electrical resistivity of the product). | 0 | Metallurgy |
There are at least three distinct mechanisms in which pRb can repress transcription of E2F-regulated promoters. Though these mechanisms are known, it is unclear which are the most important for the control of the cell cycle.
E2Fs are a family of proteins whose binding sites are often found in the promoter regions of genes for cell proliferation or progression of the cell cycle. E2F1 to E2F5 are known to associate with proteins in the pRb-family of proteins while E2F6 and E2F7 are independent of pRb. Broadly, the E2Fs are split into activator E2Fs and repressor E2Fs though their role is more flexible than that on occasion. The activator E2Fs are E2F1, E2F2 and E2F3 while the repressor E2Fs are E2F4, E2F5 and E2F6. Activator E2Fs along with E2F4 bind exclusively to pRb. pRb is able to bind to the activation domain of the activator E2Fs which blocks their activity, repressing transcription of the genes controlled by that E2F-promoter. | 1 | Gene expression + Signal Transduction |
He joined the Baltimore Copper Smelting & Rolling Company in 1890, becoming vice president in 1895, and later, president of the company. Under his management, the company became one of the major copper producer of the United States. In 1928, the company merged with five other copper companies, to create the Revere Copper Company. Described as "one of the foremost metallurgists of his time", Peirce became the vice president, director and a member of the Executive Committee of Revere from its incorporation in 1928 until his resignation in 1933. | 0 | Metallurgy |
Anaerobic corrosion (also known as hydrogen corrosion) is a form of metal corrosion occurring in anoxic water. Typically following aerobic corrosion, anaerobic corrosion involves a redox reaction that reduces hydrogen ions and oxidizes a solid metal. This process can occur in either abiotic conditions through a thermodynamically spontaneous reaction or biotic conditions through a process known as bacterial anaerobic corrosion. Along with other forms of corrosion, anaerobic corrosion is significant when considering the safe, permanent storage of chemical waste. | 0 | Metallurgy |
The protein encoded by this gene mediates transcriptional control by interaction with the Krüppel-associated box repression domain found in many transcription factors. The protein localizes to the nucleus and is thought to associate with specific chromatin regions. The protein is a member of the tripartite motif family. This tripartite motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region.
KAP1 is a ubiquitously expressed protein involved in many critical functions including: transcriptional regulation, cellular differentiation and proliferation, DNA damage repair, viral suppression, and apoptosis. Its functionality is dependent upon post-translational modifications. Sumoylated TRIM28 can assemble epigenetic machinery for gene silencing, while phosphorylated TRIM28 is involved in DNA repair. | 1 | Gene expression + Signal Transduction |
An electric arc furnace used for steelmaking consists of a refractory-lined vessel, usually water-cooled in larger sizes, covered with a retractable roof, and through which one or more graphite electrodes enter the furnace.
The furnace is primarily split into three sections:
* the shell, which consists of the sidewalls and lower steel "bowl";
* the hearth, which consists of the refractory that lines the lower bowl;
* the roof, which may be refractory-lined or water-cooled, and can be shaped as a section of a sphere, or as a frustum (conical section). The roof also supports the refractory delta in its centre, through which one or more graphite electrodes enter.
The hearth may be hemispherical in shape, or in an eccentric bottom tapping furnace (see below), the hearth has the shape of a halved egg. In modern meltshops, the furnace is often raised off the ground floor, so that ladles and slag pots can easily be maneuvered under either end of the furnace. Separate from the furnace structure is the electrode support and electrical system, and the tilting platform on which the furnace rests. Two configurations are possible: the electrode supports and the roof tilt with the furnace, or are fixed to the raised platform.
A typical alternating current furnace is powered by a three-phase electrical supply and therefore has three electrodes. Electrodes are round in section, and typically in segments with threaded couplings, so that as the electrodes wear, new segments can be added. The arc forms between the charged material and the electrode; the charge is heated both by current passing through the charge and by the radiant energy evolved by the arc. The electric arc temperature reaches around , thus causing the lower sections of the electrodes to glow incandescently when in operation. The electrodes are automatically raised and lowered by a positioning system, which may use either electric winch hoists or hydraulic cylinders. The regulating system maintains approximately constant current and power input during the melting of the charge, even though scrap may move under the electrodes as it melts. The mast arms holding the electrodes can either carry heavy busbars (which may be hollow water-cooled copper pipes carrying current to the electrode clamps) or be "hot arms", where the whole arm carries the current, increasing efficiency. Hot arms can be made from copper-clad steel or aluminium. Large water-cooled cables connect the bus tubes or arms with the transformer located adjacent to the furnace. The transformer is installed in a vault and is cooled by pump-circulated transformer oil, with the oil being cooled by water via heat exchangers.
The furnace is built on a tilting platform so that the liquid steel can be poured into another vessel for transport. The operation of tilting the furnace to pour molten steel is called "tapping". Originally, all steelmaking furnaces had a tapping spout closed with refractory that washed out when the furnace was tilted, but often modern furnaces have an eccentric bottom tap-hole (EBT) to reduce inclusion of nitrogen and slag in the liquid steel. These furnaces have a taphole that passes vertically through the hearth and shell, and is set off-centre in the narrow "nose" of the egg-shaped hearth. It is filled with refractory sand, such as olivine, when it is closed off. Modern plants may have two shells with a single set of electrodes that can be transferred between the two; one shell preheats scrap while the other shell is utilised for meltdown. Other DC-based furnaces have a similar arrangement, but have electrodes for each shell and one set of electronics.
AC furnaces usually exhibit a pattern of hot and cold-spots around the hearth perimeter, with the cold-spots located between the electrodes. Modern furnaces mount oxygen-fuel burners in the sidewall and use them to provide chemical energy to the cold-spots, making the heating of the steel more uniform. Additional chemical energy is provided by injecting oxygen and carbon into the furnace; historically this was done through lances (hollow mild-steel tubes) in the slag door, but now this is mainly done through wall-mounted injection units that combine the oxygen-fuel burners and the oxygen or carbon injection systems into one unit.
A mid-sized modern steelmaking furnace would have a transformer rated about 60,000,000 volt-amperes (60 MVA), with a secondary voltage between 400 and 900 volts and a secondary current in excess of 44,000 amperes. In a modern shop such a furnace would be expected to produce a quantity of 80 tonnes of liquid steel in approximately 50 minutes from charging with cold scrap to tapping the furnace. In comparison, basic oxygen furnaces can have a capacity of 150–300 tonnes per batch, or "heat", and can produce a heat in 30–40 minutes. Enormous variations exist in furnace design details and operation, depending on the end product and local conditions, as well as ongoing research to improve furnace efficiency. The largest scrap-only furnace (in terms of tapping weight and transformer rating) is a DC furnace operated by Tokyo Steel in Japan, with a tap weight of 420 tonnes and fed by eight 32 MVA transformers for 256 MVA total power. | 0 | Metallurgy |
For a given stress profile and temperature, the point lies in a particular "deformation field". If the values place the point near the center of a field, it is likely that the primary mechanism by which the material will fail, i.e.: the type and rate of failure expected, grain boundary diffusion, plasticity, Nabarro–Herring creep, etc. If however, the stress and temperature conditions place the point near the boundary between two deformation mechanism regions then the dominating mechanism is less clear. Near the boundary of the regimes there can be a combination of mechanisms of deformation occurring simultaneously. Deformation mechanism maps are only as accurate as the number of experiments and calculations undertaken in their creation.
For a given stress and temperature, the strain rate and deformation mechanism of a material is given by a point on the map. By comparing maps of various materials, crystal structures, bonds, grain sizes, etc., studies of these materials properties on plastic flow can be conducted and a more complete understanding of deformation in materials is obtained. | 0 | Metallurgy |
Three out of 10 advanced colorectal tumors had mutations leading to premature termination of the SFRP1 translation product. The mutations were two single-base deletions (26delG and 67delG) and a single-base change (G450A), which generates an in-frame stop codon. These three mutations were found within the first exon, which was shown previously to be sufficient for Wnt antagonist activity by itself [26, 32]. Of the 10 tumors analyzed, no truncating mutations were found in the second or third exons of SFRP1.
An additional 51 tumors were analyzed via direct sequence analysis, yielding 49 clearly interpretable results. Only the first exon was sequenced for stop codon mutations, but none were found. This indicates that point mutation is not a frequent method of inactivation of the SFRP1 gene in colorectal cancer. | 1 | Gene expression + Signal Transduction |
Thousands of residents assembled to pay respects to Tom at his funeral filling the south end of Stockton High Street and the entire length of Bridge Road. His funeral procession, was four deep and numbered about two thousand people – an unusual turnout for a 40 year old industrialist and engineer. | 0 | Metallurgy |
A galvanic cell or voltaic cell, named after the scientists Luigi Galvani and Alessandro Volta, respectively, is an electrochemical cell in which an electric current is generated from spontaneous oxidation–reduction reactions. A common apparatus generally consists of two different metals, each immersed in separate beakers containing their respective metal ions in solution that are connected by a salt bridge or separated by a porous membrane.
Volta was the inventor of the voltaic pile, the first electrical battery. Common usage of the word battery has evolved to include a single Galvanic cell, but the first batteries had many Galvanic cells. | 0 | Metallurgy |
TLRs are present in vertebrates as well as invertebrates. Molecular building blocks of the TLRs are represented in bacteria and in plants, and plant pattern recognition receptors are well known to be required for host defence against infection. The TLRs thus appear to be one of the most ancient, conserved components of the immune system.
In recent years TLRs were identified also in the mammalian nervous system. Members of the TLR family were detected on glia, neurons and on neural progenitor cells in which they regulate cell-fate decision.
It has been estimated that most mammalian species have between ten and fifteen types of toll-like receptors. Thirteen TLRs (named simply TLR1 to TLR13) have been identified in humans and mice together, and equivalent forms of many of these have been found in other mammalian species. However, equivalents of certain TLR found in humans are not present in all mammals. For example, a gene coding for a protein analogous to TLR10 in humans is present in mice, but appears to have been damaged at some point in the past by a retrovirus. On the other hand, mice express TLRs 11, 12, and 13, none of which is represented in humans. Other mammals may express TLRs that are not found in humans. Other non-mammalian species may have TLRs distinct from mammals, as demonstrated by the anti-cell-wall TLR14, which is found in the Takifugu pufferfish. This may complicate the process of using experimental animals as models of human innate immunity.
Vertebrate TLRs are divided by similarity into the families of TLR 1/2/6/10/14/15, TLR 3, TLR 4, TLR 5, TLR 7/8/9, and TLR 11/12/13/16/21/22/23. | 1 | Gene expression + Signal Transduction |
There are other ways by which messages can be degraded, including non-stop decay and silencing by Piwi-interacting RNA (piRNA), among others. | 1 | Gene expression + Signal Transduction |
The Dimetcote patent was approved in 1948 by the U.S. Patent Office. The owner of the patent is PPG Industries. Dimetcote, which was created to protect the surface of metal, could be coloured by being mixed with other paints. | 0 | Metallurgy |
On June 17, 2004, a children's playground "City of Smiles" was opened in the park area of the plant. In the "City of Smiles" a sports area and playground, a railway for children, as well as a zoo were arranged, which contained a mouflon, a Bactrian camel, a pony, a donkey, a collared peccary, a raccoon, a red-headed duck, a chubataya duck, a mandarin duck, a wood duck, a pechanka, a Muscovy duck, a common pochard, a coypu, a rhea ostrich, a bush wallabi, a macaque monkey, a rhesus monkey, a Romanian pheasant, a trogopan pheasant, chickens, a golden pheasant, a royal pheasant, a common peacock, a guinea fowl, gray nymphs, rose-ringed parakeets, a demoiselle crane, kings, strassers, pigeons, pectoral sandpiper, trumpeters, a porcupine, a Cameroon goat, a llama, a spotted deer, a European fallow deer, a Barbary sheep, a savannah zebra, and an American bison. | 0 | Metallurgy |
In molecular biology and genetics, transcriptional regulation is the means by which a cell regulates the conversion of DNA to RNA (transcription), thereby orchestrating gene activity. A single gene can be regulated in a range of ways, from altering the number of copies of RNA that are transcribed, to the temporal control of when the gene is transcribed. This control allows the cell or organism to respond to a variety of intra- and extracellular signals and thus mount a response. Some examples of this include producing the mRNA that encode enzymes to adapt to a change in a food source, producing the gene products involved in cell cycle specific activities, and producing the gene products responsible for cellular differentiation in multicellular eukaryotes, as studied in evolutionary developmental biology.
The regulation of transcription is a vital process in all living organisms. It is orchestrated by transcription factors and other proteins working in concert to finely tune the amount of RNA being produced through a variety of mechanisms. Bacteria and eukaryotes have very different strategies of accomplishing control over transcription, but some important features remain conserved between the two. Most importantly is the idea of combinatorial control, which is that any given gene is likely controlled by a specific combination of factors to control transcription. In a hypothetical example, the factors A and B might regulate a distinct set of genes from the combination of factors A and C. This combinatorial nature extends to complexes of far more than two proteins, and allows a very small subset (less than 10%) of the genome to control the transcriptional program of the entire cell. | 1 | Gene expression + Signal Transduction |
Calmodulin belongs to one of the two main groups of calcium-binding proteins, called EF hand proteins. The other group, called annexins, bind calcium and phospholipids such as lipocortin. Many other proteins bind calcium, although binding calcium may not be considered their principal function in the cell. | 1 | Gene expression + Signal Transduction |
The nucleus accumbens (NAc) has a significant role in addiction. In the nucleus accumbens of mice, repeated cocaine exposure resulted in reduced TET1 messenger RNA (mRNA) and reduced TET1 protein expression. Similarly, there was a ~40% decrease in TET1 mRNA in the NAc of human cocaine addicts examined postmortem.
As indicated above in learning and memory, a short hairpin RNA (shRNA) is an artificial RNA molecule with a tight hairpin turn that can be used to silence target gene expression via RNA interference. Feng et al. injected shRNA targeted to TET1 in the NAc of mice. This could reduce TET1 expression in the same manner as reduction of TET1 expression with cocaine exposure. They then used an indirect measure of addiction, conditioned place preference. Conditioned place preference can measure the amount of time an animal spends in an area that has been associated with cocaine exposure, and this can indicate an addiction to cocaine. Reduced Tet1 expression caused by shRNA injected into the NAc robustly enhanced cocaine place conditioning. | 1 | Gene expression + Signal Transduction |
Leaving alone remote antiquity and starting with Imperial Rome, the working of bronze, inspired probably by conquered Greece, is clearly seen. There are ancient bronze doors in the Temple of Romulus in the Roman Forum; others from the baths of Caracalla are in the Lateran Basilica, which also contains four fine gilt bronze fluted columns of the Corinthian order. The Naples Museum contains a large collection of domestic utensils of bronze, recovered from the buried towns of Pompeii and Herculaneum, which show a high degree of perfection in the working of the metal, as well as a wide application of its use. A number of moorings in the form of finely modelled animal heads, made in the 1st century AD, and recovered from Lake Nemi in the Alban hills some years ago, show a further acquaintance with the skilful working of this metal. The throne of Dagobert in the Bibliothèque Nationale, Paris, appears to be a Roman bronze curule chair, with back and part of the arms added by the Abbot Suger in the 12th century.
Byzantium, from the time when Constantine made it the seat of empire, in the early part of the 4th century, was for 1,000 years renowned for its works in metal. Its position as a trade centre between East and West attracted all the finest work provided by the artistic skills of craftsmen from Syria, Egypt, Persia, Asia Minor and the northern shores of the Black Sea, and for 400 years, until the beginning of the Iconoclastic period in the first half of the 8th century, its output was enormous. Several Italian churches still retain bronze doors cast in Constantinople in the later days of the Eastern Empire, such as those presented by the members of the Pantaleone family, in the latter half of the 11th century, to the churches at Amalfi, Monte Cassino, Atrani and Monte Gargano. Similar doors are at Salerno; and St Mark's, Venice, also has doors of Greek origin. | 0 | Metallurgy |
Another mechanism involving the structure of the 3′-UTR is called alternative polyadenylation (APA), which results in mRNA isoforms that differ only in their 3′-UTRs. This mechanism is especially useful for complex organisms as it provides a means of expressing the same protein but in varying amounts and locations. It is utilized by about half of human genes. APA can result from the presence of multiple polyadenylation sites or mutually exclusive terminal exons. Since it can affect the presence of protein and miRNA binding sites, APA can cause differential expression of mRNA transcripts by influencing their stability, export to the cytoplasm, and translation efficiency. | 1 | Gene expression + Signal Transduction |
The majority of prostaglandin signaling occurs via GPCRs (see above) although certain prostaglandins activate nuclear receptors in the PPAR family. (See article eicosanoid receptors for more information). | 1 | Gene expression + Signal Transduction |
The United States became interested in gas turbine development around 1905. From 1910-1915, austenitic ( γ phase) stainless steels were developed to survive high temperatures in gas turbines. By 1929, 80Ni-20Cr alloy was the norm, with small additions of Ti and Al. Although early metallurgists did not know it yet, they were forming small γ' precipitates in Ni-based superalloys. These alloys quickly surpassed Fe- and Co-based superalloys, which were strengthened by carbides and solid solution strengthening.
Although Cr was great for protecting the alloys from oxidation and corrosion up to 700 °C, metallurgists began decreasing Cr in favor of Al, which had oxidation resistance at much higher temperatures. The lack of Cr caused issues with hot corrosion, so coatings needed to be developed.
Around 1950, vacuum melting became commercialized, which allowed metallurgists to create higher purity alloys with more precise composition.
In the 60s and 70s, metallurgists changed focus from alloy chemistry to alloy processing. Directional solidification was developed to allow columnar or even single-crystal turbine blades. Oxide dispersion strengthening could obtain very fine grains and superplasticity. | 0 | Metallurgy |
The Wnt protein family includes a large number of cysteine-rich glycoproteins. The Wnt proteins activate signal transduction cascades via three different pathways, the canonical Wnt pathway, the noncanonical planar cell polarity (PCP) pathway, and the noncanonical Wnt/Ca pathway. Wnt proteins appear to control a wide range of developmental processes and have been seen as necessary for control of spindle orientation, cell polarity, cadherin mediated adhesion, and early development of embryos in many different organisms. Current research has indicated that deregulation of Wnt signaling plays a role in tumor formation, because at a cellular level, Wnt proteins often regulated cell proliferation, cell morphology, cell motility, and cell fate. | 1 | Gene expression + Signal Transduction |
Curvibacter sp. is a gram-negative curved rod-formed bacterium which is the main colonizer of the epithelial cell surfaces of the early branching metazoan Hydra vulgaris. Sequencing the complete genome uncovered a circular chromosome (4.37 Mb), a plasmid (16.5 kb), and two operons coding each for an AHL (N-acyl-homoserine lactone) synthase (curI1 and curI2) and an AHL receptor (curR1 and curR2). Moreover, a study showed that these host associated Curvibacter bacteria produce a broad spectrum of AHL, explaining the presence of those operons. As mentioned before, AHL are the quorum sensing molecules of gram-negative bacteria, which means Curvibacter has a quorum sensing activity.
Even though their function in host-microbe interaction is largely unknown, Curvibacter quorum-sensing signals are relevant for host-microbe interactions. Indeed, due to the oxidoreductase activity of Hydra, there is a modification of AHL signalling molecules (3-oxo-homoserine lactone into 3-hydroxy-homoserine lactone) which leads to a different host-microbe interaction. On one hand, a phenotypic switch of the colonizer Curvibacter takes place. The most likely explanation is that the binding of 3-oxo-HSL and 3-hydroxy-HSL causes different conformational changes in the AHL receptors curR1 and curR2. As a result, there is a different DNA-binding motif affinity and thereby different target genes are activated. On the other hand, this switch modifies its ability to colonize the epithelial cell surfaces of Hydra vulgaris. Indeed, one explanation is that with a 3-oxo-HSL quorum-sensing signal, there is an up-regulation of flagellar assembly. Yet, flagellin, the main protein component of flagella, can act as an immunomodulator and activate the innate immune response in Hydra. Therefore, bacteria have less chance to evade the immune system and to colonize host tissues. Another explanation is that 3-hydroxy-HSL induces carbon metabolism and fatty acid degradation genes in Hydra. This allows the bacterial metabolism to adjust itself to the host growth conditions, which is essential for the colonization of the ectodermal mucus layer of Hydrae. | 1 | Gene expression + Signal Transduction |
Secreted by leukocytes, respectively fibroblasts, IFNα IFNβ together regulate antiviral immunity, cell proliferation and anti-tumor effects. In viral infection signalling pathway, either of IFNα or β binds to IFN receptor (IFNAR), composed of IFNAR1 and IFNAR2, immediately followed by the phosphorylation of STAT1, STAT4 and IFN target genes. During the initial phase of viral infection in NK cells, STAT1 activation is replaced by the activation of STAT4. | 1 | Gene expression + Signal Transduction |
Calcineurin inhibitors such as tacrolimus are used to suppress the immune system in organ allotransplant recipients to prevent rejection of the transplanted tissue. | 1 | Gene expression + Signal Transduction |
Iron was never smelted by Native Americans, thus the New World never entered a proper "Iron Age" before European discovery, and the term is not used of the Americas. But there was limited use of native (unsmelted) iron ore, from magnetite, iron pyrite and ilmenite (iron–titanium), especially in the Andes (Chavin and Moche cultures) and Mesoamerica, after 900 BCE and until . Various forms of iron ore were mined,
drilled and highly polished. There is considerable evidence that this technology, its raw materials and end products were widely traded in Mesoamerica throughout the Formative era (2000–200BCE).
Lumps of iron pyrite, magnetite, and other materials were mostly shaped into mirrors, pendants, medallions, and headdress ornaments for decorative and ceremonial effect.
However, concave iron ore mirrors were apparently used for firing and optical purposes by the Olmec (1500–400BCE) and Chavin (900–300BCE) cultures,
and ilmenite "beads" may have served as hammers for fine work.
The Olmec and Izapa (300BCE – 100CE) also seem to have used iron magnetism to align and position monuments.
They may have developed a zeroth-order compass using a magnetite bar.
Some Mesoamerican uses of native iron seem to have been military. Steven Jones proposed that the Olmec sewed ilmenite "beads" into protective mail armour or helmets. Iron pyrite mosaics and plates formed protective tezcacuitlapalli (mirrored back flap shields) and breastplate ornaments in the military attire of the Teotihuacan (100 BCE – 600 CE), Toltec (800–1150 CE) and Chichen Itza (800–1200 CE) cultures. | 0 | Metallurgy |
The following inclusion types can also be found in aluminium alloys: alumina needles (AlO), nitrides (AlN), iron oxides (FeO), manganese oxides (MnO), fluorides (NaAlF, NaF, CaF, …), aluminium borides (AlB, AlB), borocarbides (AlCB).
Bone ash (Ca(PO)) sometimes added to patch cracks in the trough can be found as inclusions in the melt. | 0 | Metallurgy |
*ATP2C1 NM_014382
*ATP5A1 NM_004046 Homo sapiens ATP synthase, H+ transporting, mitochondrial F1 complex, alpha
*ATP5B NM_001686
*ATP5C1 NM_005174
*ATP5D NM_001687 Homo sapiens ATP synthase, H+ transporting, mitochondrial F1 complex, delta
*ATP5F1 NM_001688
*ATP5G2 NM_005176
*ATP5G3 NM_001689 Homo sapiens ATP synthase, H+ transporting, mitochondrial F0 complex, subunit c
*ATP5H NM_006356 Homo sapiens ATP synthase, H+ transporting, mitochondrial F0 complex, subunit d
*ATP5J NM_001685
*ATP5J2 NM_004889 Homo sapiens ATP synthase, H+ transporting, mitochondrial F0 complex, subunit f,
*ATP5J2-PTCD1 NM_001198879
*ATP5L NM_006476
*ATP5O NM_001697 Homo sapiens ATP synthase, H+ transporting, mitochondrial F1 complex, O subunit
*ATP5S NM_015684
*ATP5SL NM_018035
*ATP6AP1 NM_001183 Homo sapiens ATPase, H+ transporting, lysosomal interacting protein 1 (ATP6IP1),
*ATP6V0A2 NM_012463
*ATP6V0B NM_004047 Homo sapiens ATPase, H+ transporting, lysosomal 21kDa, V0 subunit c (ATP6V0B),
*ATP6V0C NM_001694 Homo sapiens ATPase, H+ transporting, lysosomal 16kDa, V0 subunit c (ATP6V0C),
*ATP6V0D1 NM_004691
*ATP6V0E1 NM_003945
*ATP6V1C1 NM_001695
*ATP6V1D NM_015994
*ATP6V1E1 NM_001696 Homo sapiens ATPase, H+ transporting, lysosomal 31kDa, V1 subunit E isoform 1
*ATP6V1F NM_004231 Homo sapiens ATPase, H+ transporting, lysosomal 14kDa, V1 subunit F (ATP6V1F),
*ATP6V1G1 NM_004888 Homo sapiens ATPase, H+ transporting, lysosomal 13kDa, V1 subunit G isoform 1
*ATP6V1H NM_015941
*ATPAF2 NM_145691
*ATPIF1 NM_016311 | 1 | Gene expression + Signal Transduction |
The Polevskoy Copper Smelting Plant (), also known as Polevaya or Poleva, was one of the major metallurgical facilities located in Polevskoy, in Sverdlovsk Oblast of Russia. | 0 | Metallurgy |
TFB is recruited by another translation factor, TBP, after it recognizes the TATA box and bends the DNA so transcription can initiate. TFB stabilizes the TBP-DNA complex so that the proteins can recruit RNA Polymerase and melt the DNA via a yet-unknown mechanism. This opening of the DNA is not an energy-dependent process in Archaea; since TFB, TBP, and RNAP are located more closely to each other than in Eukarya, the tightness of the proteins and their interactions may provide more areas of contact to open the DNA as well as physically strain the DNA, which leads to an open transcription complex.
TFB uses a zinc ion (Zn) as a cofactor and accepts one ion per subunit. | 1 | Gene expression + Signal Transduction |
Magnetation is the processing of iron ore tailings, the waste product of iron ore mines, to recover hematite. Crushed mine tailings are mixed with water to create a slurry; the slurry is then pumped through magnetic separation chambers to extract hematite. Commercial interest in this process stems from the possibility of extracting additional iron from tailings supplied by existing mines, increasing their yield. | 0 | Metallurgy |
Modern furnaces are equipped with an array of supporting facilities to increase efficiency, such as ore storage yards where barges are unloaded. The raw materials are transferred to the stockhouse complex by ore bridges, or rail hoppers and ore transfer cars. Rail-mounted scale cars or computer controlled weight hoppers weigh out the various raw materials to yield the desired hot metal and slag chemistry. The raw materials are brought to the top of the blast furnace via a skip car powered by winches or conveyor belts.
There are different ways in which the raw materials are charged into the blast furnace. Some blast furnaces use a "double bell" system where two "bells" are used to control the entry of raw material into the blast furnace. The purpose of the two bells is to minimize the loss of hot gases in the blast furnace. First, the raw materials are emptied into the upper or small bell which then opens to empty the charge into the large bell. The small bell then closes, to seal the blast furnace, while the large bell rotates to provide specific distribution of materials before dispensing the charge into the blast furnace. A more recent design is to use a "bell-less" system. These systems use multiple hoppers to contain each raw material, which is then discharged into the blast furnace through valves. These valves are more accurate at controlling how much of each constituent is added, as compared to the skip or conveyor system, thereby increasing the efficiency of the furnace. Some of these bell-less systems also implement a discharge chute in the throat of the furnace (as with the Paul Wurth top) in order to precisely control where the charge is placed.
The iron making blast furnace itself is built in the form of a tall structure, lined with refractory brick, and profiled to allow for expansion of the charged materials as they heat during their descent, and subsequent reduction in size as melting starts to occur. Coke, limestone flux, and iron ore (iron oxide) are charged into the top of the furnace in a precise filling order which helps control gas flow and the chemical reactions inside the furnace. Four "uptakes" allow the hot, dirty gas high in carbon monoxide content to exit the furnace throat, while "bleeder valves" protect the top of the furnace from sudden gas pressure surges. The coarse particles in the exhaust gas settle in the "dust catcher" and are dumped into a railroad car or truck for disposal, while the gas itself flows through a venturi scrubber and/or electrostatic precipitators and a gas cooler to reduce the temperature of the cleaned gas.
The "casthouse" at the bottom half of the furnace contains the bustle pipe, water cooled copper tuyeres and the equipment for casting the liquid iron and slag. Once a "taphole" is drilled through the refractory clay plug, liquid iron and slag flow down a trough through a "skimmer" opening, separating the iron and slag. Modern, larger blast furnaces may have as many as four tapholes and two casthouses. Once the pig iron and slag has been tapped, the taphole is again plugged with refractory clay.
The tuyeres are used to implement a hot blast, which is used to increase the efficiency of the blast furnace. The hot blast is directed into the furnace through water-cooled copper nozzles called tuyeres near the base. The hot blast temperature can be from 900 °C to 1300 °C (1600 °F to 2300 °F) depending on the stove design and condition. The temperatures they deal with may be 2000 °C to 2300 °C (3600 °F to 4200 °F). Oil, tar, natural gas, powdered coal and oxygen can also be injected into the furnace at tuyere level to combine with the coke to release additional energy and increase the percentage of reducing gases present which is necessary to increase productivity.
The exhaust gasses of a blast furnace are generally cleaned in the dust collector – such as an inertial separator, a baghouse, or an electrostatic precipitator. Each type of dust collector has strengths and weaknesses – some collect fine particles, some coarse particles, some collect electrically charged particles. Effective exhaust clearing relies on multiple stages of treatment. Waste heat is usually collected from the exhaust gases, for example by the use of a Cowper stove, a variety of heat exchanger.
The IEA Green House Gas R&D Programme (IEAGHG) has shown that in an integrated steel plant, 70% of the is directly from the blast furnace gas (BFG). It is possible to use carbon capture technology on the BFG before the BFG goes on to be used for heat exchange processes within the plant. In 2000, the IEAGHG estimated using that chemical absorption to capture BFG would cost $35/t of (an additional $8–20/t of would be required for transportation and storage). This would make the entire steel production process in a plant 15–20% more expensive. | 0 | Metallurgy |
The process by which the dosage and choice of flocculant are selected is called a jar test. The equipment used for jar testing consists of one or more beakers, each equipped with a paddle mixer. After the addition of flocculants, rapid mixing takes place, followed by slow mixing and later the sedimentation process. Samples can then be taken from the aqueous phase in each beaker. | 0 | Metallurgy |
An outron is a nucleotide sequence at the 5' end of the primary transcript of a gene that is removed by a special form of RNA splicing during maturation of the final RNA product. Whereas intron sequences are located inside the gene, outron sequences lie outside the gene. | 1 | Gene expression + Signal Transduction |
Cyclic AMP-dependent protein kinases (protein kinase A) are activated by the signal cascade originated by the activation of the G protein Gs by the LHCG-receptor. Activated Gs binds the enzyme adenylate cyclase and this leads to the production of cyclic AMP (cAMP). Cyclin AMP-dependent protein kinases are present as tetramers with two regulatory subunits and two catalytic subunits. Upon binding of cAMP to the regulatory subunits, the catalytic units are released and initiate the phosphorylation of proteins leading to the physiologic action. Cyclic AMP is degraded by phosphodiesterase and release 5’AMP. One of the targets of protein kinase A is the Cyclic AMP Response Element Binding Protein, CREB, which binds DNA in the cell nucleus via direct interactions with specific DNA sequences called cyclic AMP response elements (CRE); this process results in the activation or inactivation of gene transcription.
The signal is amplified by the involvement of cAMP and the resulting phosphorylation. The process is modified by prostaglandins. Other cellular regulators that participate are the intracellular calcium concentration regulated by phospholipase C activation, nitric oxide, and other growth factors.
Other pathways of signaling exist for the LHCGR. | 1 | Gene expression + Signal Transduction |
Transcriptional regulation is one of the most common ways for an organism to alter gene expression. The use of activation and coactivation allows for greater control over when, where and how much of a protein is produced. This enables each cell to be able to quickly respond to environmental or physiological changes and helps to mitigate any damage that may occur if it were otherwise unregulated. | 1 | Gene expression + Signal Transduction |
Chromatin architectural remodeling is implicated in the process of cellular senescence, which is related to, and yet distinct from, organismal aging. Replicative cellular senescence refers to a permanent cell cycle arrest where post-mitotic cells continue to exist as metabolically active cells but fail to proliferate. Senescence can arise due to age associated degradation, telomere attrition, progerias, pre-malignancies, and other forms of damage or disease. Senescent cells undergo distinct repressive phenotypic changes, potentially to prevent the proliferation of damaged or cancerous cells, with modified chromatin organization, fluctuations in remodeler abundance, and changes in epigenetic modifications. Senescent cells undergo chromatin landscape modifications as constitutive heterochromatin migrates to the center of the nucleus and displaces euchromatin and facultative heterochromatin to regions at the edge of the nucleus. This disrupts chromatin-lamin interactions and inverts of the pattern typically seen in a mitotically active cell. Individual Lamin-Associated Domains (LADs) and Topologically Associating Domains (TADs) are disrupted by this migration which can affect cis interactions across the genome. Additionally, there is a general pattern of canonical histone loss, particularly in terms of the nucleosome histones H3 and H4 and the linker histone H1. Histone variants with two exons are upregulated in senescent cells to produce modified nucleosome assembly which contributes to chromatin permissiveness to senescent changes. Although transcription of variant histone proteins may be elevated, canonical histone proteins are not expressed as they are only made during the S phase of the cell cycle and senescent cells are post-mitotic. During senescence, portions of chromosomes can be exported from the nucleus for lysosomal degradation which results in greater organizational disarray and disruption of chromatin interactions.
Chromatin remodeler abundance may be implicated in cellular senescence as knockdown or knockout of ATP-dependent remodelers such as NuRD, ACF1, and SWI/SNP can result in DNA damage and senescent phenotypes in yeast, C. elegans, mice, and human cell cultures. ACF1 and NuRD are downregulated in senescent cells which suggests that chromatin remodeling is essential for maintaining a mitotic phenotype. Genes involved in signaling for senescence can be silenced by chromatin confirmation and polycomb repressive complexes as seen in PRC1/PCR2 silencing of p16. Specific remodeler depletion results in activation of proliferative genes through a failure to maintain silencing. Some remodelers act on enhancer regions of genes rather than the specific loci to prevent re-entry into the cell cycle by forming regions of dense heterochromatin around regulatory regions.
Senescent cells undergo widespread fluctuations in epigenetic modifications in specific chromatin regions compared to mitotic cells. Human and murine cells undergoing replicative senescence experience a general global decrease in methylation; however, specific loci can differ from the general trend. Specific chromatin regions, especially those around the promoters or enhancers of proliferative loci, may exhibit elevated methylation states with an overall imbalance of repressive and activating histone modifications. Proliferative genes may show increases in the repressive mark H3K27me3 while genes involved in silencing or aberrant histone products may be enriched with the activating modification H3K4me3. Additionally, upregulating histone deacetylases, such as members of the sirtuin family, can delay senescence by removing acetyl groups that contribute to greater chromatin accessibility. General loss of methylation, combined with the addition of acetyl groups results in a more accessible chromatin conformation with a propensity towards disorganization when compared to mitotically active cells. General loss of histones precludes addition of histone modifications and contributes changes in enrichment in some chromatin regions during senescence. | 1 | Gene expression + Signal Transduction |
* BS 1881:204 Testing concrete. Recommendations on the use of electromagnetic covermeters
* DGZfP:B2: Guideline “für Bewehrungsnachweis und Überdeckungsmessung bei Stahl- und Spannbeton”
* DIN 1045: Guideline Concrete, reinforced and prestressed concrete structures
* ACI Concrete Practices Non Destructive testing 228.2R-2.51: Covermeters | 0 | Metallurgy |
One ancient process for extracting the silver from lead was cupellation. Lead was melted in a bone ash test or cupel and air blown across the surface. This oxidised the lead to litharge, and also oxidised other base metals present, the silver (and gold if present) remaining unoxidised.
In the 18th century, the process was carried on using a kind of reverberatory furnace, but differing from the usual kind in that air was blown over the surface of the molten lead from bellows or (in the 19th century) blowing cylinders. | 0 | Metallurgy |
Nucleoporins (Nups) are the main constituent proteins of NPCs and have been shown to play multiple roles in mediating several processes involved in gene gating. While it has been known that the nuclear periphery serves as the primary location for most heterochromatin, telomeric and centrosomal DNA, studies in the yeast Saccharomyces cerevisiae have shown that NPCs containing Nup2p and Prp20p create boundaries of active gene expression near the nuclear envelope and prevent the spread of heterochromatin at the nuclear periphery. These Nup2p and Prp20p proteins also provide a location for the binding of chromatin.
Some inducible genes in yeast been shown to re-locate to the nuclear periphery by binding NPCs composed of specific Nups. Several of these inducible genes, including GAL1, INO1, TSA2, and HSP104 contain gene recruitment sequences (GRSs) found in the promoter, which are necessary for the attachment of the gene to the NPC by way of DNA binding to specific Nups. This initial relocation of genes containing GRSs requires the action of Snf1-p dependent Spt-Ada-Gcn5 acetyltransferase (SAGA), a chromatin remodeling complex, as well as several mRNA export proteins, for their transcriptional activation at the nuclear periphery.
In the fruit fly Drosophila melanogaster large stretches of chromatin are bound to Nups Nup153 and Megator. These genomic regions are often found on the male X chromosome, which exhibits high levels of transcriptional activity due to dosage compensation; these regions of chromatin are termed Nup-associated regions (NARs). Depletion of Nup153 causes a drastic decrease in expression of genes associated with NARs and decreased the affinity of these gene sequences with the nuclear periphery. Other Nups such as Nup50, Nup60 and Nup98 are associated with genes involved in development and the cell cycle.
In mammalian model systems activated genes to be transcribed are shuttled in a Nup-dependent manner, though some experiments in human cell lines show a reversal of movement, from the periphery of the nucleus to the nucleoplasmic center. mRNP (messenger ribonucleoprotein) leaving sites of transcription in the nuclear center follows the same path through the nucleus to the NPC, which suggests that mRNA/protein complexes can move through the nucleus by a directed means, through interchromatin channels. In mice and human cell lines a transmembrane Nup, Nup210, has been shown to be necessary for the proper transcription of several genes involved in neurogenesis and myogenesis. RNAi knockdown of Nup210 prevents myogenesis in mouse stem cells, but has no effect on nuclear transport, though it has been speculated that Nup210 or other NPC-associated factors could influence chromatin architecture to mediate routes for mRNP/mRNA to the nuclear membrane. Movement of transcriptionally active genes from the periphery of the nucleus to the nucleoplasmic region has also been observed in human cell lines. The human Mash1, GAFB and β-globin loci have all been observed moving away from the nuclear periphery when transcriptionally active. This seems to contradict the gene-gating hypothesis, but this process may still be mediated by Nup98, a soluble Nup protein that shuttles between the nucleoplasm and NPC at the nuclear membrane. Nup98 seems to be responsible for the transport of many RNAs from the center of the nucleus to the nuclear lamina. Nup98 antibodies introduced in the nucleus block the export of many RNAs. A large body of data exists which supports the role of nulceoporins, both anchored to NPCs and soluble, in the role of mediating the transport of mRNA and for the proper transcription of active genes, though numerous other protein factors influence these complex processes. | 1 | Gene expression + Signal Transduction |
Direct reduced iron (DRI), also called sponge iron, is produced from the direct reduction of iron ore (in the form of lumps, pellets, or fines) into iron by a reducing gas which either contains elemental carbon (produced from natural gas or coal) or hydrogen. When hydrogen is used as the reducing gas there are no greenhouse gases produced. Many ores are suitable for direct reduction.
Direct reduction refers to solid-state processes which reduce iron oxides to metallic iron at temperatures below the melting point of iron. Reduced iron derives its name from these processes, one example being heating iron ore in a furnace at a high temperature of in the presence of the reducing gas syngas, a mixture of hydrogen and carbon monoxide, or pure hydrogen. | 0 | Metallurgy |
After the mRNA is completed and cleaved off at the poly-A signal sequence, the left-over (residual) RNA strand remains bound to the DNA template and the RNA polymerase II unit, continuing to be transcribed. After this cleavage, a so-called exonuclease binds to the residual RNA strand and removes the freshly transcribed nucleotides one at a time (also called degrading the RNA), moving towards the bound RNA polymerase II. This exonuclease is XRN2 (5-3 Exoribonuclease 2) in humans. This model proposes that XRN2 proceeds to degrade the uncapped residual RNA from 5 to 3 until it reaches the RNA pol II unit. This causes the exonuclease to push off the RNA pol II unit as it moves past it, terminating the transcription while also cleaning up the residual RNA strand.
Similar to Rho-dependent termination, XRN2 triggers the dissociation of RNA polymerase II by either pushing the polymerase off of the DNA template or pulling the template out of the RNA polymerase. The mechanism by which this happens remains unclear, however, and has been challenged not to be the sole cause of the dissociation.
In order to protect the transcribed mRNA from degradation by the exonuclease, a 5 cap is added to the strand. This is a modified guanine added to the front of mRNA, which prevents the exonuclease from binding and degrading the RNA strand. A 3 poly(A) tail is added to the end of a mRNA strand for protection from other exonucleases as well. | 1 | Gene expression + Signal Transduction |
Some genes involved in critical developmental processes contain multiple enhancers of overlapping function. Secondary enhancers, or "shadow enhancers", may be found many kilobases away from the primary enhancer ("primary" usually refers to the first enhancer discovered, which is often closer to the gene it regulates). On its own, each enhancer drives nearly identical patterns of gene expression. Are the two enhancers truly redundant? Recent work has shown that multiple enhancers allow fruit flies to survive environmental perturbations, such as an increase in temperature. When raised at an elevated temperature, a single enhancer sometimes fails to drive the complete pattern of expression, whereas the presence of both enhancers permits normal gene expression. | 1 | Gene expression + Signal Transduction |
The results showed that global warming potential and acidification potential were the most significant environmental impacts. On average producing a tonne of steel emits 1.8 tonnes of . However, a steel mill using a top gas recycling blast furnace (TGRBF) producing a tonne of steel will emit 0.8 to 1.3 tonnes of depending upon the recycle rate of the TGRBF. | 0 | Metallurgy |
Xiang et al. found a new approach in inhibiting tumour growth and metastasis by simultaneously attacking both the tumour and its vasculature by a cytotoxic T cell (CTL) response against the survivin protein, which will later result in the activation of apoptosis in tumour cells.
The idea and general principle behind his technique is described below. Mice were immunized with the oral vaccination and then subjected to tumour challenges by injecting them in the chest with a certain number of tumour cells and a Matrigel pre-formed extracellular matrix to hold the tumour cells together. The mice were sacrificed and the endothelium tissue was stained with a fluorescent dye that would aid in the quantification of tumour neovascularisation using a Matrigel assay. There was found to be a significant difference between the control and test groups, whereby mice given the vaccine had less angiogenesis from the tumour challenge than the control mice that were not given any of the vaccine prior to tumour challenge. In vitro assays and other tests were also performed to validate the idea of the occurrence of an actual immune response to support what they observed in the mice. For example, the spleen on the challenged mice were isolated and measured for the presence of any cytokines, and specifically activated immune cell groups that would indicative that a specific immune response did occur upon vaccination. The isolated CTLs specific for the survivin protein after vaccination of the mice were used in cytoxicity assays where mice tumour cells expressing survivin were shown to be killed upon incubation with the specific CTLs.
By using an oral DNA vaccine carried in an attenuated non-virulent form of Salmonella typhimurium, which co-encoded secretory chemokine CCL21 and survivin protein in C57BL/6J mice, Xiang et al. have been able to elicit an immune response carried out by dendritic cells (DCs) and CTLs to eliminate and suppress the pulmonary metastases of non-small cell lung carcinoma. The activation of the immune response is most likely taking place in the secondary lymphoid organ called the Peyer's Patch in the small intestine where DCs take up the survivin protein by phagocytosis and present them on their surface receptors to naive CD8+ T cells (uninactivated CTL) to achieve a specific immune response targeting survivin exclusively. Activated CTLs specific for a particular antigen kill their target cells by first recognizing parts of the survivin protein expressed on MHC I (immunohistocompatability) proteins presented on the surface of tumour cells and vasculature and then releasing granules that induce the tumour cells to undergo apoptosis. The DNA vaccine contained the CCL21 secretory chemokine as a way to enhance the likelihood of eliciting the immune response by better mediating the physical interaction of the antigen-presenting DCs and the naive CD8+ T cells, resulting in a greater likelihood of immune activation. | 1 | Gene expression + Signal Transduction |
SPIKE was developed by Ron Shamir's computational biology group in cooperation with the group of Yosef Shiloh, an Israel Prize recipient for his research in systems biology, and the group of Karen Avraham, a leading researcher of human deafness, all from Tel Aviv University. | 1 | Gene expression + Signal Transduction |
Inside eukaryotic cells, there is a balance between the processes of translation and mRNA decay. Messages that are being actively translated are bound by ribosomes, the eukaryotic initiation factors eIF-4E and eIF-4G, and poly(A)-binding protein. eIF-4E and eIF-4G block the decapping enzyme (DCP2), and poly(A)-binding protein blocks the exosome complex, protecting the ends of the message. The balance between translation and decay is reflected in the size and abundance of cytoplasmic structures known as P-bodies. The poly(A) tail of the mRNA is shortened by specialized exonucleases that are targeted to specific messenger RNAs by a combination of cis-regulatory sequences on the RNA and trans-acting RNA-binding proteins. Poly(A) tail removal is thought to disrupt the circular structure of the message and destabilize the cap binding complex. The message is then subject to degradation by either the exosome complex or the decapping complex. In this way, translationally inactive messages can be destroyed quickly, while active messages remain intact. The mechanism by which translation stops and the message is handed-off to decay complexes is not understood in detail. | 1 | Gene expression + Signal Transduction |
A discussion of all mediator subunits is beyond the scope of this article, but details of one of the subunits are illustrative of the types of information that may be gathered for other subunits. | 1 | Gene expression + Signal Transduction |
The Krupp–Renn process was a direct reduction steelmaking process used from the 1930s to the 1970s. It used a rotary furnace and was one of the few technically and commercially successful direct reduction processes in the world, acting as an alternative to blast furnaces due to their coke consumption. The Krupp-Renn process consumed mainly hard coal and had the unique characteristic of partially melting the charge. This method is beneficial for processing low-quality or non-melting ores, as their waste material forms a protective layer that can be easily separated from the iron. It generates Luppen, nodules of pre-reduced iron ore, which can be easily melted down.
The first industrial furnaces emerged in the 1930s, firstly in Nazi Germany and then in the Japanese Empire. During the 1950s, new facilities were constructed, notably in Czechoslovakia and West Germany. The process was discontinued in the early 1970s, with a few nuances.
It was unproductive, intricate to master, and only pertinent to certain ores. In the beginning of the 21st century, Japan modernized the process to manufacture ferronickel, which is the sole surviving variant. | 0 | Metallurgy |
Each candidate CRM (cCRM) is cloned upstream of a reporter gene. Compared to traditional reporter assays, the main innovation is the use of fluorescence activated cell sorting (FACS) of dissociated cells, instead of microscopy, to screen for tissue-specific enhancers. This approach utilizes a two-marker system: in each embryo, one marker (here, the rat CD2 cell surface protein) is used to label cells of a specific tissue for being sorted by FACS, and the other marker (here, green fluorescent protein GFP) is used as a reporter of CRM activity.
Cells are sorted according to their tissue type and then by GFP fluorescence, and the cCRMs are recovered by PCR from double-positive sorted cells, and from total input cells. High-throughput sequencing of both populations then allows measuring the relative abundance of each cCRM in input and sorted populations; one can then assess the enrichment or depletion of each cCRM in double-positive cells versus input as a measure of activity in the CD2-positive cell type being tested. | 1 | Gene expression + Signal Transduction |
It is known that Middle Minoan bronze work flourished as an independent native art. To the very beginning of this epoch belongs the largest sword of the age, found in the palace of Malia. It is a flat blade, 79 cm long, with a broad base and a sharp point; there is a gold and crystal hilt but no ornament on the blade. A dagger of somewhat later date, now in the Metropolitan Museum of New York is the earliest piece of decorated bronze from Crete. Both sides of the blade are engraved with drawings: bulls fighting and a man hunting boars in a thicket. Slightly later again (MM III) are a series of blades from mainland Greece, which must be attributed to Cretan craftsmen, with ornament in relief, or incised, or inlaid with gold, silver and niello. The most elaborate inlays, pictures of men hunting lions and cats hunting birds, are on daggers from the shaftgraves of Mycenae. These large designs cover the whole of the flat blade except its edge, but on swords, best represented by finds at Knossos, the ornament is restricted to the high midribs which are an essential feature of the longer blades. The type belongs to the beginning of the Late Minoan (Mycenaean) age. The hilt is made in one piece with the blade; it has a horned guard, a flanged edge for holding grip-scales, and a tang for a pommel. The scales were ivory or some other perishable substance and were fixed with bronze rivets; the pommels were often made of crystal. A rapier from Zapher Papoura (Knossos) is 91.3 cm long; its midrib and hilt-flange are engraved with bands of spiral coils, and its rivet-heads (originally gold-cased) with whorls. Ordinary Mycenaean blades are enriched with narrow mouldings, parallel to the midribs of swords and daggers, or to the curved backs of one-edged knives. The spearheads have hammered sockets. Other tools and implements are oval two-edged knives, square-ended razors, cleavers, chisels, hammers, axes, mattocks, ploughshares and saws. Cycladic and mainland Greek (Helladic) weapons show no ornament but include some novel types. A tanged spearhead has a slit (Cycladic) or slipped (Helladic) blade for securing the shaft; and the halberd, a west European weapon, was in use in the Middle Helladic Greece. There are few remains of Mycenaean metal armour; a plain cheek-piece from a helmet comes from Ialysos in Rhodes, and a pair of greaves from Enkomi in Cyprus. One of the greaves has wire riveted to its edge for fastening. | 0 | Metallurgy |
In-situ leaching is also called "solution mining". This process initially involves drilling of holes into the ore deposit. Explosives or hydraulic fracturing are used to create open pathways within the deposit for solution to penetrate into. Leaching solution is pumped into the deposit where it makes contact with the ore. The solution is then collected and processed. The Beverley uranium deposit is an example of in-situ leaching. | 0 | Metallurgy |
The termination of translation requires coordination between release factor proteins, the mRNA sequence, and ribosomes. Once a termination codon is read, release factors RF-1, RF-2, and RF-3 contribute to the hydrolysis of the growing polypeptide, which terminates the chain. Bases downstream the stop codon affect the activity of these release factors. In fact, some bases proximal to the stop codon suppress the efficiency of translation termination by reducing the enzymatic activity of the release factors. For instance, the termination efficiency of a UAAU stop codon is near 80% while the efficiency of UGAC as a termination signal is only 7%. | 1 | Gene expression + Signal Transduction |
The van Arkel–de Boer process, also known as the iodide process or crystal-bar process, was the first industrial process for the commercial production of pure ductile titanium, zirconium and some other metals. It was developed by Anton Eduard van Arkel and Jan Hendrik de Boer in 1925. Now it is used in the production of small quantities of ultrapure titanium and zirconium. It primarily involves the formation of the metal iodides and their subsequent decomposition to yield pure metal.
This process was superseded commercially by the Kroll process. | 0 | Metallurgy |
Culcheth Laboratories was a British metallurgical and nuclear research institute that researched the structural design of nuclear reactors and reactor pressure vessels in Culcheth, Cheshire, then in south Lancashire and now in the borough of Warrington. | 0 | Metallurgy |
Signal transducer and activator of transcription 4 (STAT4) is a transcription factor belonging to the STAT protein family, composed of STAT1, STAT2, STAT3, STAT4, STAT5A, STAT5B, STAT6. STAT proteins are key activators of gene transcription which bind to DNA in response to cytokine gradient. STAT proteins are a common part of Janus kinase (JAK)- signalling pathways, activated by cytokines.STAT4 is required for the development of Th1 cells from naive CD4+ T cells and IFN-γ production in response to IL-12. There are two known STAT4 transcripts, STAT4α and STAT4β, differing in the levels of interferon-gamma (IFN-γ )production downstream. | 1 | Gene expression + Signal Transduction |
Pioneer factors can also actively affect transcription by directly opening up condensed chromatin in an ATP-independent process. This is a common trait of fork head box factors (which contain a winged helix DNA-binding domain that mimics the DNA-binding domain of the linker H1 histone), and NF-Y (whose NF-YB and NF-YC subunits contain histone-fold domains similar to those of the core histones H2A/H2B). | 1 | Gene expression + Signal Transduction |
Despite being used in 90% of gold production: gold cyanidation is controversial due to the toxic nature of cyanide. Although aqueous solutions of cyanide degrade rapidly in sunlight, the less-toxic products, such as cyanates and thiocyanates, may persist for some years. The famous disasters have killed few people — humans can be warned not to drink or go near polluted water, but cyanide spills can have a devastating effect on rivers, sometimes killing everything for several miles downstream. The cyanide is soon washed out of river systems and, as long as organisms can migrate from unpolluted areas upstream, affected areas can soon be repopulated. According to Romanian authorities, in the Someș river below Baia Mare, the plankton returned to 60% of normal within 16 days of the spill; the numbers were not confirmed by Hungary or Yugoslavia.
Famous cyanide spills include:
Such spills have prompted fierce protests at new mines that involve use of cyanide, such as Roşia Montană in Romania, Lake Cowal in Australia, Pascua Lama in Chile, and Bukit Koman in Malaysia. | 0 | Metallurgy |
PTWA can be used to apply a coating to wear surfaces of engine or transmission components, serving as a plain bearing. For the cylinder bores of hypoeutectic aluminum-silicon alloy blocks, PTWA's main advantages over cast iron liners are reduced weight and cost. The thinner bore surface also allows for more compact bore spacing, and can potentially provide better heat transfer.
Automotive engines that use PTWA include the BMW B58, Nissan VR38DETT, and Ford Coyote. Caterpillar and Ford also use PTWA to remanufacture engines. | 0 | Metallurgy |
A number of lactose derivatives or analogs have been described that are useful for work with the lac operon. These compounds are mainly substituted galactosides, where the glucose moiety of lactose is replaced by another chemical group.
* Isopropyl-β-D-thiogalactopyranoside (IPTG) is frequently used as an inducer of the lac operon for physiological work. IPTG binds to repressor and inactivates it, but is not a substrate for β-galactosidase. One advantage of IPTG for in vivo studies is that since it cannot be metabolized by E. coli. Its concentration remains constant and the rate of expression of lac p/o-controlled genes is not a variable in the experiment. IPTG intake is dependent on the action of lactose permease in P. fluorescens, but not in E. coli.
* Phenyl-β-D-galactose (phenyl-Gal) is a substrate for β-galactosidase, but does not inactivate repressor and so is not an inducer. Since wild type cells produce very little β-galactosidase, they cannot grow on phenyl-Gal as a carbon and energy source. Mutants lacking repressor are able to grow on phenyl-Gal. Thus, minimal medium containing only phenyl-Gal as a source of carbon and energy is selective for repressor mutants and operator mutants. If 10 cells of a wild type strain are plated on agar plates containing phenyl-Gal, the rare colonies which grow are mainly spontaneous mutants affecting the repressor. The relative distribution of repressor and operator mutants is affected by the target size. Since the lacI gene encoding repressor is about 50 times larger than the operator, repressor mutants predominate in the selection.
* Thiomethyl galactoside [TMG] is another lactose analog. These inhibit the lacI repressor. At low inducer concentrations, both TMG and IPTG can enter the cell through the lactose permease. However at high inducer concentrations, both analogs can enter the cell independently. TMG can reduce growth rates at high extracellular concentrations.
* Other compounds serve as colorful indicators of β-galactosidase activity.
** ONPG is cleaved to produce the intensely yellow compound, orthonitrophenol and galactose, and is commonly used as a substrate for assay of β-galactosidase in vitro.
** Colonies that produce β-galactosidase are turned blue by X-gal (5-bromo-4-chloro-3-indolyl-β-D-galactoside) which is an artificial substrate for B-galactosidase whose cleavage results in galactose and 4-Cl,3-Br indigo thus producing a deep blue color.
* Allolactose is an isomer of lactose and is the inducer of the lac operon. Lactose is galactose-β(1→4)-glucose, whereas allolactose is galactose-β(1→6)-glucose. Lactose is converted to allolactose by β-galactosidase in an alternative reaction to the hydrolytic one. A physiological experiment which demonstrates the role of LacZ in production of the "true" inducer in E. coli cells is the observation that a null mutant of lacZ can still produce LacY permease when grown with IPTG, a non-hydrolyzable analog of allolactose, but not when grown with lactose. The explanation is that processing of lactose to allolactose (catalyzed by β-galactosidase) is needed to produce the inducer inside the cell. | 1 | Gene expression + Signal Transduction |
The first high-volume product (> 5Mio actuators / year) is an automotive valve used to control low pressure pneumatic bladders in a car seat that adjust the contour of the lumbar support / bolsters. The overall benefits of SMA over traditionally-used solenoids in this application (lower noise/EMC/weight/form factor/power consumption) were the crucial factor in the decision to replace the old standard technology with SMA.
The 2014 Chevrolet Corvette became the first vehicle to incorporate SMA actuators, which replaced heavier motorized actuators to open and close the hatch vent that releases air from the trunk, making it easier to close. A variety of other applications are also being targeted, including electric generators to generate electricity from exhaust heat and on-demand air dams to optimize aerodynamics at various speeds. | 0 | Metallurgy |
In viruses this phenomenon may be programmed to occur at particular sites and allows the virus to encode multiple types of proteins from the same mRNA. Notable examples include HIV-1 (human immunodeficiency virus), RSV (Rous sarcoma virus) and the influenza virus (flu), which all rely on frameshifting to create a proper ratio of 0-frame (normal translation) and "trans-frame" (encoded by frameshifted sequence) proteins. Its use in viruses is primarily for compacting more genetic information into a shorter amount of genetic material.
In eukaryotes it appears to play a role in regulating gene expression levels by generating premature stops and producing nonfunctional transcripts. | 1 | Gene expression + Signal Transduction |
Copper and its alloys are readily joined by mechanical techniques, such as crimping, staking, riveting, and bolting; or by bonding techniques, such as soldering, brazing and welding. Selection of the best joining technique is determined by service requirements, joint configuration, thickness of components, and alloy composition.
Soldering is the preferred joining method where strong, watertight joints are required, such as for internal gutters, roofing, and flashing applications. A soldered seam joins two pieces of copper into a cohesive unit that expands and contracts as one piece. Well-soldered seams are often stronger than the original base material and provide many years of service.
Mechanical fasteners, such as screws, bolts, and rivets, are often used to strengthen the joints and seams. Continuous, long runs of soldered seams can cause stress fractures and should therefore be avoided.
Common 50-50 tin-lead bar solder is often used for uncoated copper; 60-40 tin-lead solder is used for lead-coated copper. Many lead-free solders are also acceptable.
Adhesives can be used in certain applications. Relatively thin sheet alloys can be bonded to plywood or certain types of foam which act as rigid insulation.
Brazing is the preferred method for joining pipe and tube copper alloys. Copper metal sections are joined with a non-ferrous filler material with a melting point above 800 degrees Fahrenheit but below the melting point of the base metals. Blind or concealed joints are recommended since the color match of silver filler material is fair to poor.
Welding is a process where pieces of copper are effectively melted together, either by flame, electricity, or high pressure. With increasing availability of modern TIG welding equipment, welding of even light-gauge copper decorative elements is gaining acceptance.
Instructional videos are available regarding fluxing and soldering techniques; how to make flat seam solder joints, double-lock standing seams, lap seams, soldering vertical sheet copper lap seams, and stitches (including the butterfly stitch); as well as copper tinning, bending, flaring, and brazing. | 0 | Metallurgy |
The Mountain Pass deposit is in a 1.4 billion-year-old Precambrian carbonatite intruded into gneiss. It contains 8% to 12% rare-earth oxides, mostly contained in the mineral bastnäsite. Gangue minerals include calcite, barite, and dolomite. It is regarded as a world-class rare-earth mineral deposit. The metals that can be extracted from it include: cerium, lanthanum, neodymium, and europium.
At 1 July 2020, Proven and Probable Reserves, using a 3.83% total rare-earth oxide (REO) cutoff grade, were 18.9 million tonnes of ore containing 1.36 million tonnes of REO at an average grade of 7.06% REO. | 0 | Metallurgy |
From the 17th century onwards, several European travelers observed the steel manufacturing in South India, at Mysore, Malabar and Golconda. The word "wootz" appears to have originated as a mistranscription of wook; the Tamil language root word for the alloy is urukku. Anothertheory says that the word is a variation of uchcha or ucha ("superior"). According to one theory, the word ukku is based on the meaning "melt, dissolve". Other Dravidian languages have similar-sounding words for steel: ukku in Kannada and Telugu, and urukku in Malayalam. When Benjamin Heyne inspected the Indian steel in Ceded Districts and other Kannada-speaking areas, he was informed that the steel was ucha kabbina ("superior iron"), also known as ukku tundu in Mysore.
Legends of wootz steel and Damascus swords aroused the curiosity of the European scientific community from the 17th to the 19th century. The use of high-carbon alloys was little known in Europe previously and thus the research into wootz steel played an important role in the development of modern English, French and Russian metallurgy.
In 1790, samples of wootz steel were received by Sir Joseph Banks, president of the British Royal Society, sent by Helenus Scott. These samples were subjected to scientific examination and analysis by several experts.
Specimens of daggers and other weapons were sent by the Rajas of India to the Great Exhibition in London in 1851 and 1862 International Exhibition. Though the arms of the swords were beautifully decorated and jeweled, they were most highly prized for the quality of their steel. The swords of the Sikhs were said to bear bending and crumpling, and yet be fine and sharp. | 0 | Metallurgy |
[http://regulondb.ccg.unam.mx/menu/using_regulondb/tutorials/project_glossary/index.jsp Check the glossary for all definitions]. | 1 | Gene expression + Signal Transduction |
The use of EAFs allows steel to be made from a 100% scrap metal feedstock. This greatly reduces the energy required to make steel when compared with primary steelmaking from ores.
Another benefit is flexibility: while blast furnaces cannot vary their production by much and can remain in operation for years at a time, EAFs can be rapidly started and stopped, allowing the steel mill to vary production according to demand.
Although steelmaking arc furnaces generally use scrap steel as their primary feedstock, if hot metal from a blast furnace or direct-reduced iron is available economically, these can also be used as furnace feed.
As EAFs require large amounts of electrical power, many companies schedule their operations to take advantage of off-peak electricity pricing.
A typical steelmaking arc furnace is the source of steel for a mini-mill, which may make bars or strip product. Mini-mills can be sited relatively near the markets for steel products, so the transport requirements are less than for an integrated mill, which would commonly be sited near a harbor for better access to shipping.
Electric arc furnace steelmaking results in lower carbon dioxide emissions of around 0.6 ton CO per ton of steel produced, which is significantly lower than the conventional production route via blast furnaces and the basic oxygen furnace. | 0 | Metallurgy |
Endonucleases are enzymes that recognise and cleave nucleic acid segments and they can be used to direct DNA assembly. Of the different types of restriction enzymes, the type II restriction enzymes are the most commonly available and used because their cleavage sites are located near or in their recognition sites. Hence, endonuclease-mediated assembly methods make use of this property to define DNA parts and assembly protocols. | 1 | Gene expression + Signal Transduction |
Mutations to coactivator genes leading to loss or gain of protein function have been linked to diseases and disorders such as birth defects, cancer (especially hormone dependent cancers), neurodevelopmental disorders and intellectual disability (ID), among many others. Dysregulation leading to the over- or under-expression of coactivators can detrimentally interact with many drugs (especially anti-hormone drugs) and has been implicated in cancer, fertility issues and neurodevelopmental and neuropsychiatric disorders. For a specific example, dysregulation of CREB-binding protein (CBP)—which acts as a coactivator for numerous transcription factors within the central nervous system (CNS), reproductive system, thymus and kidneys—has been linked to Huntington's disease, leukaemia, Rubinstein-Taybi syndrome, neurodevelopmental disorders and deficits of the immune system, hematopoiesis and skeletal muscle function. | 1 | Gene expression + Signal Transduction |
For a long time, it was normal procedure for a decommissioned blast furnace to be demolished and either be replaced with a newer, improved one, or to have the entire site demolished to make room for follow-up use of the area. In recent decades, several countries have realized the value of blast furnaces as a part of their industrial history. Rather than being demolished, abandoned steel mills were turned into museums or integrated into multi-purpose parks. The largest number of preserved historic blast furnaces exists in Germany; other such sites exist in Spain, France, the Czech Republic, Great Britain. Japan, Luxembourg, Poland, Romania, Mexico, Russia and the United States. | 0 | Metallurgy |
Geoksyur Oasis, located in the foothills of the Kopetdag, to the east of Altyndepe, is in the center of a cluster of tepes in the desert region on the northern Iranian border. It extends over an area of 12 ha. It is to the east of the city of Tedzhen. Even though in the Aneolithic Period (4th – early 3rd century BC), the space between houses was used for burials, the settlement was not a cemetery but rather a settlement which was affected by shifting sand dunes and scarcity of water. Geoksyr was revealed to contain "adobe multi-room houses and group burial chambers". Ceramics were also found with dichromatic paintings and many female terracotta figurines. The culture of Geoksyurtepe was correlated with an eastern Anau group of tribes linked to Elam and Mesopotamia. | 0 | Metallurgy |
Scholars previously believed that sub-Saharan Africans either did not have a period of using copper until the nineteenth century (going from the Stone Age directly into the Iron Age), or that they started smelting iron and copper at the same time. Copper smelting is thought to have been practiced in Nubia, during the early Old Kingdom c. 2686–2181 BC.
The principal evidence for this claim is an Egyptian outpost established in Buhen (near today's Sudanese-Egyptian border) around 2600 BC to smelt copper ores from Nubia. Alongside this, a crucible furnace dating to 2300–1900 BC for bronze casting has been found at the temple precinct at Kerma (in present-day northern Sudan), however the source of the tin remains unknown. Over the next millennium Nubians developed great skill in working copper and other known metals.
Discoveries in the Agadez Region of Niger evidence signs of copper metallurgy as early as 2000 BC. This date pre-dates the use of iron by a thousand years. Copper metallurgy seems to have been an indigenous invention in this area, because there is no clear evidence of influences from Northern Africa, and the Saharan wet phase was coming to an end, hindering human interactions across the Saharan region. It appeared to not be fully developed copper metallurgy, which suggests it was not from external origins. The people used native copper at first, and experimented with different furnace styles in order to smelt the ore between 2500 and 1500 BC.
Copper metallurgy has been recorded at Akjoujt in western Mauritania. The Akjoujt site is later than Agadez, dating back to around 850 BC. There is evidence of mining between 850 and 300 BC. Radiocarbon dates from the Grotte aux Chauves-souris mine shows that the extraction and smelting of malachite goes back to the early fifth century BC. A number of copper artifacts—including arrow points, spearheads, chisels, awls and plano-convex axes as well as bracelets, bead and earrings—were found at Neolithic sites in the region.
Collecting dates from Tropical Africa has been extremely difficult. No dates are available for the copper mine in pre-colonial Nigeria, and the earliest dates available south of the equator are around 345 AD at Naviundu springs near Lubumbashi in the Democratic Republic of Congo (DRC). Kansanshi mine in Zambia and Kipushi mine in the DRC date to between the fifth and twelfth centuries. Sites further south have produced later dates, for example the Thakadu mines in Botswana date to between 1480 and 1680; other major mines in Botswana, Namibia, and South Africa remain undated. | 0 | Metallurgy |
False brinelling was first mentioned by Almen in 1937. Almen found that wheel bearings were damaged before they were used by customers. Furthermore, he found that the bearings were more damaged for long-distance shipping of the cars and that the season of shipping also had an influence. The reason for the damaged bearings were micro-oscillations which occurred due to the shipping. The small oscillations result in fatigue cracking, followed by release of particles that subsequently start to abrasively damage the contact area between a ball and the bearing race, resulting in a typical wear damage. Because the damage has a similar look to brinelling, it was called false brinelling.
Although the car-delivery problem has been solved, there are many modern examples. A major maintenance problem are the pitch bearings in wind turbines, for which specialty greases had to be developed that result in almost no false brinelling damage. Similar damage may also occur in electric and electronic contacts that are subjected to vibrations during use, think of aerospace and automotive connectors and even remote control battery compartments. Although the damage in these areas may not be as severe as the false brinelling in bearings, the damage mechanisms are similar and result in the creation of particles in the contact that can severely influence the electrical connection.
Also, generators or pumps may fail or need service because of this damage, so it is common to have a nearby spare unit which is left off most of the time but brought into service when needed. Surprisingly, however, vibration from the operating unit can cause bearing failure in the unit which is switched off. When that unit is turned on, the bearings may be noisy due to damage, and may fail completely within a few days or weeks even though the unit and its bearings are otherwise new. Common solutions include: keeping the spare unit at a distance from the one which is on and vibrating; manually rotating shafts of the spare units on a regular (for example, weekly) basis; or regularly switching between the units so that both are in regular (for example, weekly) operation.
Until recently, bicycle headsets tended to suffer from false brinelling in the "straight ahead" steering position, due to small movements caused by flexing of the fork. Good modern headsets incorporate a plain bearing to accommodate this flexing, leaving the ball race to provide pure rotational movement.
Bearings of modern wind turbines are often affected by false brinelling. Especially the pitch bearing, which is used under oscillation, shows often false brinelling damages. | 0 | Metallurgy |
*Johnson, D. W., Johnson, R. T., & Smith, K. A. (1998). Cooperative learning returns to college what evidence is there that it works?. Change: the magazine of higher learning, 30(4), 26–35.
*Smith, K.A. (2000). Going deeper: Formal small-group learning in large classes. In MacGregor, J., Cooper, J., Smith, K, and Robinson, P., eds. Strategies for Energizing Large Classes: From Small Groups to Learning Communities. New Directions for Teaching and Learning, 81, 25–46. San Francisco: Jossey-Bass.
*Johnson, D.W., Johnson, R.T., and Smith, K.A. (2000). Constructive controversy: The power of intellectual conflict. Change, 32 (1), 28–37.
*Wankat, P. C., Felder, R. M., Smith, K. A., & Oreovicz, F. S. (2002). The scholarship of teaching and learning in engineering. In M.T. Huber & S.P. Morreale, eds., Disciplinary styles in the scholarship of teaching and learning, 217–237.
*Smith, K. A., Sheppard, S. D., Johnson, D. W., & Johnson, R. T. (2005). Pedagogies of engagement: Classroom‐based practices. Journal of Engineering Education, 94(1), 87–101.
*Johnson, D. W., Johnson, R. T., & Smith, K. (2007). The state of cooperative learning in postsecondary and professional settings. Educational psychology review, 19, 15–29.
*Froyd, J. E., Wankat, P. C., & Smith, K. A. (2012). Five major shifts in 100 years of engineering education. Proceedings of the IEEE, 100(Special Centennial Issue), 1344–1360.
*Singer, S. & Smith, K.A. (2013). Discipline-Based Education Research: Understanding and Improving Learning in Undergraduate Science and Engineering. Guest Editorial. Journal of Engineering Education, 102, 468–471.
*Lichtenstein, G., Chen, H.L., Smith, K.A. & Maldonado, T.A. (2013). Retention and Persistence of Women and Minorities Along the Engineering Pathway in the United States. In A. Johri & B. Olds (Eds), Cambridge Handbook on Engineering Education Research.
*Johnson, D. W., Johnson, R. T., & Smith, K. A. (2014). Cooperative learning: Improving university instruction by basing practice on validated theory. Journal on Excellence in University Teaching, 25(4), 1-26.
*Streveler, R.A. & Smith, K.A. (2020). Opinion: Course Design in the Time of Coronavirus: Put on your Designer's CAP. Advances in Engineering Education, COVID-19 Issue.
*Smith, K.A. & Starfield, A.M. (2023). Reflections on modeling and teaching modeling. The Journal of Undergraduate Mathematics and Its Applications (UMAP), 44(2).
*Smith, K.A. & Felder, R.M. (2023). Cooperative Learning in Engineering Education: The Story of an Ongoing Uphill Climb. In Robyn Gillies, Barbara Millis, and Neil Davidson, eds. Contemporary Global Perspectives on Cooperative Learning. New York: Routledge. | 0 | Metallurgy |
Sepro Tyre Driven Grinding Mills are designed for small and medium capacity grinding applications, specifically small tonnage plants, regrinding mills, reagent prep and lime slaking. Sepro Pneumatic Tyre Driven (PTD) mills provide an alternative to standard trunnion drive systems. The drive consists of multiple gears boxes and electric motors directly connected and controlled through an AC variable frequency drive. Shell supported mills such as the Sepro PTD mills minimize stress on the mill shell by spreading the power drive over the full length of the mill. Sepro Mills are suitable for ball, rod and pebble charges and are available with overflow or grate discharge to suit the application. Shell supported mills such as the Sepro PTD Grinding Mills minimize stress on the shell by spreading the power drive over the full length of the unit. | 0 | Metallurgy |
Culcheth is just over one mile north of junction 11 of the M62 motorway on the A574.
It was administered by the Research and Development Branch of the United Kingdom Atomic Energy Authority (UKAEA). | 0 | Metallurgy |
Polarized light (PL) is very useful when studying the structure of metals with non-cubic crystal structures (mainly metals with hexagonal close-packed (hcp) crystal structures). If the specimen is prepared with minimal damage to the surface, the structure can be seen vividly in cross-polarized light (the optic axis of the polarizer and analyzer are 90 degrees to each other, i.e., crossed). In some cases, an hcp metal can be chemically etched and then examined more effectively with PL. Tint etched surfaces, where a thin film (such as a sulfide, molybdate, chromate or elemental selenium film) is grown epitaxially on the surface to a depth where interference effects are created when examined with BF producing color images, can be improved with PL. If it is difficult to get a good interference film with good coloration, the colors can be improved by examination in PL using a sensitive tint (ST) filter. | 0 | Metallurgy |
In humans, cAMP works by activating protein kinase A (PKA, cAMP-dependent protein kinase), one of the first few kinases discovered. It has four sub-units two catalytic and two regulatory. cAMP binds to the regulatory sub-units. It causes them to break apart from the catalytic sub-units. The catalytic sub-units make their way in to the nucleus to influence transcription. Further effects mainly depend on cAMP-dependent protein kinase, which vary based on the type of cell.
cAMP-dependent pathway is necessary for many living organisms and life processes. Many different cell responses are mediated by cAMP; these include increase in heart rate, cortisol secretion, and breakdown of glycogen and fat. cAMP is essential for the maintenance of memory in the brain, relaxation in the heart, and water absorbed in the kidney.
This pathway can activate enzymes and regulate gene expression. The activation of preexisting enzymes is a much faster process, whereas regulation of gene expression is much longer and can take up to hours. The cAMP pathway is studied through loss of function (inhibition) and gain of function (increase) of cAMP.
If cAMP-dependent pathway is not controlled, it can ultimately lead to hyper-proliferation, which may contribute to the development and/or progression of cancer. | 1 | Gene expression + Signal Transduction |
Auto Ejection Melt Spinning (AEMS) describes a type of melt spinning where ejection of the melt occurs as soon as it has liquefied, eliminating the need for a technician to manually control the flow rate, temperature, and/or release timing of the melt stream.
This modification allows for a much higher ribbon consistency between runs, and a greater level of automation in the process. | 0 | Metallurgy |
Design parameters include type of mill, milling container, milling speed, milling time, type, size, and size distribution of the grinding medium, ball-to-powder weight ratio, extent of filling the vial, milling atmosphere, process control agent, temperature of milling, and the reactivity of the species. | 0 | Metallurgy |
Scientists use a number of methods to study the complex structures and functions of the 3′ UTR. Even if a given 3′-UTR in an mRNA is shown to be present in a tissue, the effects of localization, functional half-life, translational efficiency, and trans-acting elements must be determined to understand the 3′-UTR's full functionality. Computational approaches, primarily by sequence analysis, have shown the existence of AREs in approximately 5 to 8% of human 3′-UTRs and the presence of one or more miRNA targets in as many as 60% or more of human 3′-UTRs. Software can rapidly compare millions of sequences at once to find similarities between various 3′ UTRs within the genome. Experimental approaches have been used to define sequences that associate with specific RNA-binding proteins; specifically, recent improvements in sequencing and cross-linking techniques have enabled fine mapping of protein binding sites within the transcript. Induced site-specific mutations, for example those that affect the termination codon, polyadenylation signal, or secondary structure of the 3′-UTR, can show how mutated regions can cause translation deregulation and disease. These types of transcript-wide methods should help our understanding of known cis elements and trans-regulatory factors within 3′-UTRs. | 1 | Gene expression + Signal Transduction |