text
stringlengths 105
13.7k
| label
int64 0
1
| label_text
stringclasses 2
values |
|---|---|---|
Ferrotitanium is a ferroalloy, an alloy of iron and titanium with between 10 and 20% iron and 45–75% titanium and sometimes a small amount of carbon. It is used in steelmaking as a cleansing agent for iron and steel; the titanium is highly reactive with sulfur, carbon, oxygen, and nitrogen, forming insoluble compounds and sequestering them in slag, and is therefore used for deoxidizing, and sometimes for desulfurization and denitrogenation. In steelmaking, the addition of titanium yields metal with finer grain structure. Ferrotitanium can be manufactured by mixing titanium sponge and scrap with iron and melting them together in an induction furnace. Ferrotitanium powder can be also used as a fuel in some pyrotechnic compositions. | 0 | Metallurgy |
A muffle furnace or muffle oven (sometimes retort furnace in historical usage) is a furnace in which the subject material is isolated from the fuel and all of the products of combustion, including gases and flying ash. After the development of high-temperature heating elements and widespread electrification in developed countries, new muffle furnaces quickly moved to electric designs. | 0 | Metallurgy |
To show the visitors how Birminghams iron industry developed, the main museum displays a wide range of Tannehill artifacts that have survived. Visitors, through paying a visit to the museum, can learn from the graphic exhibits how iron was made by 13 different iron companies and six rolling mills and how Alabamas iron-making industry made this state the arsenal of the Confederacy. Although Alabamas iron and steel industry experienced rapid growth during the post-war decades, Alabamas iron production had already occupied a central position in the countrys iron supply before the war ended. In the last two years of the Civil war, iron produced by Alabama furnaces accounted for 70% of the Confederate iron supply. To demonstrate the significant role Alabama played during the war , the museum displays a large number of wartime ironworks, including cookware, rifles and other weapons used by US soldiers (e.g. a 52 Cal. U.S. Spencer Repeater), cast-iron water pipes, CS artillery projectiles, the original parts of the Six Mile Bloomery Forge manufactured in 1860s, as well as a part of the Steve Phillips Collection. Notably, the artillery shells manufactured from 1862 to 1865 at the Naval Gun Works are also preserved in this museum, and this exhibition is considered as the Souths largest collection of artillery shells. In addition to the wartime iron relics, the museum preserves and demonstrates substantial numbers of historical artifacts that have witnessed the development of Alabama's iron and steel industry, such as a cast iron water pipe made in Birmingham during the 1880s.
The Iron and Steel Museum of Alabama not only displays iron relics but also preserves archaeological artifacts uncovered in this region. The site houses Walter B. Jones Centre for Industrial Archaeology, a state geologist and archeologist who devoted his lifetime to investigating Alabamas mineral and fossil fuel resources (Garrison, 2001) His geological and archaeological works are well preserved by many museums and historical institutions, including the University of Alabamas Jones Museum at Moundville Archaeological Park, as well as the Iron and Steel Museum of Alabama. In addition to the preservation of the archaeological works written by Walter Jones, the museum is further famous for its conservation of more than 10,000 archaeological artifacts that were discovered from 8 major on-site archaeological investigations from 1956 to 2008. It is noteworthy that the main museum building also houses a small research library. In this library, those who are interested in investigating the iron-making history in this country (e.g. historical researchers, scholars, and students) can find many historical archives, published materials, records, as well as first-hand accounts. | 0 | Metallurgy |
Some cases of many genetic diseases are associated with variations in promoters or transcription factors.
Examples include:
* Asthma
* Beta thalassemia
* Rubinstein-Taybi syndrome | 1 | Gene expression + Signal Transduction |
The luteinizing hormone/choriogonadotropin receptor (LHCGR), also lutropin/choriogonadotropin receptor (LCGR) or luteinizing hormone receptor (LHR), is a transmembrane receptor found predominantly in the ovary and testis, but also many extragonadal organs such as the uterus and breasts. The receptor interacts with both luteinizing hormone (LH) and chorionic gonadotropins (such as hCG in humans) and represents a G protein-coupled receptor (GPCR). Its activation is necessary for the hormonal functioning during reproduction. | 1 | Gene expression + Signal Transduction |
Adhesion G protein-coupled receptors (adhesion GPCRs) are a class of 33 human protein receptors with a broad distribution in embryonic and larval cells, cells of the reproductive tract, neurons, leukocytes, and a variety of tumours. Adhesion GPCRs are found throughout metazoans and are also found in single-celled colony forming choanoflagellates such as Monosiga brevicollis and unicellular organisms such as Filasterea. The defining feature of adhesion GPCRs that distinguishes them from other GPCRs is their hybrid molecular structure. The extracellular region of adhesion GPCRs can be exceptionally long and contain a variety of structural domains that are known for the ability to facilitate cell and matrix interactions. Their extracellular region contains the membrane proximal GAIN (GPCR-Autoproteolsis INducing) domain. Crystallographic and experimental data has shown this structurally conserved domain to mediate autocatalytic processing at a GPCR-proteolytic site (GPS) proximal to the first transmembrane helix. Autocatalytic processing gives rise to an extracellular (α) and a membrane-spanning (β) subunit, which are associated non-covalently, resulting in expression of a heterodimeric receptor at the cell surface.
Ligand profiles and in vitro studies have indicated a role for adhesion GPCRs in cell adhesion and migration. Work utilizing genetic models confined this concept by demonstrating that the primary function of adhesion GPCRs may relate to the proper positioning of cells in a variety of organ systems. Moreover, growing evidence implies a role of adhesion GPCRs in tumour cell metastasis. Formal G protein-coupled signalling has been demonstrated for a number for adhesion GPCRs, however, the orphan receptor status of many of the receptors still hampers full characterisation of potential signal transduction pathways. In 2011, the [http://www.adhesiongpcr.org/ adhesion GPCR consortium] was established to facilitate research of the physiological and pathological functions of adhesion GPCRs. | 1 | Gene expression + Signal Transduction |
When heating iron above 912 °C (1,674 °F), its crystal structure changes to a face-centered cubic (fcc) crystalline structure. In this form it is called gamma iron (γ-Fe) or austenite. γ-iron can dissolve considerably more carbon (as much as 2.04% by mass at 1,146 °C). This γ form of carbon saturation is exhibited in austenitic stainless steel. | 0 | Metallurgy |
Like all metals, gold is insoluble in a water. Gold does however exhibit the distinctive properties that in the presence of cyanide ions, it dissolves in the presence of oxygen (or air). This transformation was reported in 1783 by Carl Wilhelm Scheele, but it was not until the late 19th century, that the reactions were exploited commercially. The expansion of gold mining in the Rand of South Africa began to slow down in the 1880s, as the new deposits being found tended to be pyritic ore. The gold was difficult to extract from such ores.
In 1887, John Stewart MacArthur, working in collaboration with brothers Dr Robert and Dr William Forrest for the Tennant Company in Glasgow, Scotland, developed the MacArthur-Forrest Process for the extraction of gold ores. By suspending the crushed ore in a cyanide solution, up to 96 percent gold was extracted.
The process was first used on a large scale at the Witwatersrand in 1890, leading to a boom of investment as larger gold mines were opened up. In 1896, Bodländer confirmed that oxygen was necessary for the process, something that had been doubted by MacArthur, and discovered that hydrogen peroxide was formed as an intermediate.
The method known as heap leaching was first proposed in 1969 by the United States Bureau of Mines, and was in use by the 1970s. | 0 | Metallurgy |
If the drip rate is quicker than one drop per minute, most of the CaCO will be carried to the ground, still in solution. The leachate solution then has a chance to absorb CO from the atmosphere (or degas CO depending on reaction) and deposit the CaCO on the ground as a stalagmite.
In most locations within manmade concrete structures, calthemite stalagmites only grow to a maximum of a few centimetres high, and look like low rounded lumps. This is because of the limited supply of CaCO from the leachate seepage path through the concrete and the amount which reaches the ground. Their location may also inhibit their growth due to abrasion from vehicle tires and pedestrian traffic. | 0 | Metallurgy |
There are several, largely empirical laws of recrystallization:
* Thermally activated. The rate of the microscopic mechanisms controlling the nucleation and growth of recrystallized grains depend on the annealing temperature. Arrhenius-type equations indicate an exponential relationship.
* Critical temperature. Following from the previous rule it is found that recrystallization requires a minimum temperature for the necessary atomic mechanisms to occur. This recrystallization temperature decreases with annealing time.
* Critical deformation. The prior deformation applied to the material must be adequate to provide nuclei and sufficient stored energy to drive their growth.
* Deformation affects the critical temperature. Increasing the magnitude of prior deformation, or reducing the deformation temperature, will increase the stored energy and the number of potential nuclei. As a result, the recrystallization temperature will decrease with increasing deformation.
* Initial grain size affects the critical temperature. Grain boundaries are good sites for nuclei to form. Since an increase in grain size results in fewer boundaries this results in a decrease in the nucleation rate and hence an increase in the recrystallization temperature
* Deformation affects the final grain size. Increasing the deformation, or reducing the deformation temperature, increases the rate of nucleation faster than it increases the rate of growth. As a result, the final grain size is reduced by increased deformation. | 0 | Metallurgy |
A notable feature of eukaryotic nuclear pre-mRNA introns is the relatively high level of conservation of the primary sequences of 5 and 3 splice sites over a great range of organisms.
Between 1989 and 1991, several groups reported four independent examples of introns with a splice site that differed from the common intron:
*Cartilage matrix protein (CMP/MATN1) gene in humans and chickens
*Proliferating cell nucleolar protein P120 (NOL1) gene in humans
*Mouse Rep3 gene, presumably involved in DNA repair
*Drosophila prospero gene that encodes for a homeobox protein
In 1991 by comparing the intron sequences of P120 and CMP genes, IJ Jackson reported the existence of ATATCC (5) and YYCAC (3) splice sites in these introns. The finding indicated a possible novel splicing mechanism.
In 1994, S.L. Hall and R.A. Padgett compared the primary sequence of all reports on the four genes mentioned above. The results suggested a new type of introns with ATATCCTT 5 splice sites and YCCAC 3 splice sites and an almost invariant TCCTTAAC sequence near the 3 end of the introns (so called 3 upstream element). A search for small nuclear RNA sequences that are complementary to these splice sites suggested U12 snRNA (matches the 3 sequence) and U11 snRNA (matches the 5 sequence) as being putative factors involved in splicing of this new type of introns.
In all these four genes, the pre-mRNA contains other introns whose sequences conform to those of major class introns. Neither the size nor the position of the AT–AC intron within the host gene is conserved.
In 1996, Woan-Yuh Tarn and Joan A. Steitz described an in vitro system that splices a pre-mRNA substrate containing an AT–AC intron derived from the human P120 gene. Psoralen cross-linking confirms the base-pairing interaction predicted by Hall and Padgett between the branch site of the pre-mRNA substrate and U12 RNA. Native gel electrophoresis reveals that U11, U12, and U5 snRNPs assemble onto the P120 pre-mRNA to form splicing complexes. | 1 | Gene expression + Signal Transduction |
The classic view of pRb's role as a tumor suppressor and cell cycle regulator developed through research investigating mechanisms of interactions with E2F family member proteins. Yet, more data generated from biochemical experiments and clinical trials reveal other functions of pRb within the cell unrelated (or indirectly related) to tumor suppression. | 1 | Gene expression + Signal Transduction |
A scleroscope is a device used to measure rebound hardness. It consists of a steel ball dropped from a fixed height. The device was invented in 1907. As an improvement on this rough method, the Leeb Rebound Hardness Test, invented in the 1970s, uses the ratio of impact and rebound velocities (as measured by a magnetic inducer) to determine hardness. | 0 | Metallurgy |
Taking into account the HiFIT process during development, on same load level and same lifetime, the construction can be slimmed down specifically. Extensive experimental investigations on structural details and FEM-supported-design methods has shown the high efficiency with conventional S235, S355J2 and fine grain steels, such as S460N, S690QL and even higher strength steels. The achievable material saving makes the HiFIT application in most applications already economically viable. Considering the additional benefit of the weight advantage e.g. the achievable payload in vehicles can be increased. | 0 | Metallurgy |
A target peptide is a short (3-70 amino acids long) peptide chain that directs the transport of a protein to a specific region in the cell, including the nucleus, mitochondria, endoplasmic reticulum (ER), chloroplast, apoplast, peroxisome and plasma membrane. Some target peptides are cleaved from the protein by signal peptidases after the proteins are transported. | 1 | Gene expression + Signal Transduction |
Pre-mRNAs of the Transformer (Tra) gene of Drosophila melanogaster undergo alternative splicing via the alternative acceptor site mode. The gene Tra encodes a protein that is expressed only in females. The primary transcript of this gene contains an intron with two possible acceptor sites. In males, the upstream acceptor site is used. This causes a longer version of exon 2 to be included in the processed transcript, including an early stop codon. The resulting mRNA encodes a truncated protein product that is inactive. Females produce the master sex determination protein Sex lethal (Sxl). The Sxl protein is a splicing repressor that binds to an ISS in the RNA of the Tra transcript near the upstream acceptor site, preventing U2AF protein from binding to the polypyrimidine tract. This prevents the use of this junction, shifting the spliceosome binding to the downstream acceptor site. Splicing at this point bypasses the stop codon, which is excised as part of the intron. The resulting mRNA encodes an active Tra protein, which itself is a regulator of alternative splicing of other sex-related genes (see dsx above). | 1 | Gene expression + Signal Transduction |
# Accessibility: Run over 200 regularly updated analysis and visualization tools (that support data preprocessing, gene expression analysis, proteomics, Single nucleotide polymorphism (SNP) analysis, flow cytometry, and next-generation sequencing) and create analytic workflows without any programming through a point and click user interface.
# Reproducibility: Automated history and provenance tracking with versioning so that any user can share, repeat and understand a complete computational analysis
# Extensibility: Computational users can import their methods and code for sharing using tools that support easy creation and integration
# Multiple interfaces: Web browser, application, and programmatic interfaces make analysis modules and pipelines available to a broad range of users; public hosted server | 1 | Gene expression + Signal Transduction |
Phosphoinositide phospholipase C performs its catalytic function at the plasma membrane where the substrate PIP is present. This membrane docking is mediated mostly by lipid-binding domains (e.g. PH domain and C2 domain) that display affinity for different phospholipid components of the plasma membrane. It is important to note that research has also discovered that, in addition to the plasma membrane, phosphoinositide phospholipase C also exists within other sub-cellular regions such as the cytoplasm and nucleus of the cell. At present, it is unclear exactly what the definitive roles for these enzymes in these cellular compartments are, particularly the nucleus. | 1 | Gene expression + Signal Transduction |
In the US, more copper is recovered and put back into service from recycled material than is derived from newly mined ore. Copper's recycle value is so great that premium-grade scrap normally has at least 95% of the value of primary metal from newly mined ore. In Europe, about 50% of copper demand comes from recycling (as of 2016).
, recycled copper provided 35% of total worldwide copper usage. | 0 | Metallurgy |
*PSMA1 NM_002786
*PSMA2 NM_002787
*PSMA3 NM_002788
*PSMA4 NM_002789
*PSMA5 NM_002790
*PSMA6 NM_002791
*PSMA7 NM_002792 Homo sapiens proteasome (prosome, macropain) subunit, alpha type, 7 (PSMA7),
*PSMB1 NM_002793 Homo sapiens proteasome (prosome, macropain) subunit, beta type, 1 (PSMB1), mRNA
*PSMB2 NM_002794 Homo sapiens proteasome (prosome, macropain) subunit, beta type, 2 (PSMB2), mRNA
*PSMB3 NM_002795
*PSMB4 NM_002796 Homo sapiens proteasome (prosome, macropain) subunit, beta type, 4 (PSMB4), mRNA
*PSMB5 NM_002797
*PSMB6 NM_002798
*PSMB7 NM_002799 Homo sapiens proteasome (prosome, macropain) subunit, beta type, 7 (PSMB7), mRNA
*PSMC2 NM_002803
*PSMC3 NM_002804
*PSMC4 NM_006503
*PSMC5 NM_002805
*PSMC6 NM_002806
*PSMD1 NM_002807
*PSMD10 NM_002814
*PSMD11 NM_002815 Homo sapiens proteasome (prosome, macropain) 26S subunit, non-ATPase, 11
*PSMD12 NM_002816
*PSMD13 NM_002817
*PSMD14 NM_005805
*PSMD2 NM_002808
*PSMD3 NM_002809
*PSMD4 NM_002810
*PSMD5 NM_005047
*PSMD6 NM_014814
*PSMD7 NM_002811
*PSMD8 NM_002812 Homo sapiens proteasome (prosome, macropain) 26S subunit, non-ATPase, 8 (PSMD8),
*PSMD9 NM_002813
*PSME2 NM_002818 Homo sapiens proteasome (prosome, macropain) activator subunit 2 (PA28 beta)
*PSME3 NM_005789
*PSMF1 NM_006814
*PSMG2 NM_020232
*PSMG3 NM_032302
*PSMG4 NM_001128591
*UBA1 NM_003334 Homo sapiens ubiquitin-activating enzyme E1 (A1S9T and BN75 temperature
*UBA2 NM_005499
*UBA3 NM_003968
*UBA5 NM_024818
*UBA52 NM_003333
*UBAC2 NM_177967
*UBALD1 NM_145253
*UBAP1 NM_016525
*UBAP2L NM_014847
*UBB NM_018955 Homo sapiens ubiquitin B (UBB), mRNA
*UBC NM_021009 Homo sapiens ubiquitin C (UBC), mRNA
*UBE2A NM_003336
*UBE2B NM_003337
*UBE2D2 NM_003339 Homo sapiens ubiquitin-conjugating enzyme E2D 2 (UBC4/5 homolog, yeast)
*UBE2D3 NM_003340
*UBE2D4 NM_015983
*UBE2E1 NM_003341
*UBE2E2 NM_152653
*UBE2E3 NM_006357
*UBE2F NM_080678
*UBE2G2 NM_003343
*UBE2H NM_003344
*UBE2I NM_003345 Homo sapiens ubiquitin-conjugating enzyme E2I (UBC9 homolog, yeast) (UBE2I),
*UBE2J1 NM_016021
*UBE2J2 NM_058167
*UBE2K NM_005339
*UBE2L3 NM_003347
*UBE2M NM_003969 Homo sapiens ubiquitin-conjugating enzyme E2M (UBC12 homolog, yeast) (UBE2M),
*UBE2N NM_003348
*UBE2NL NM_001012989
*UBE2Q1 NM_017582
*UBE2R2 NM_017811
*UBE2V1 NM_021988
*UBE2V2 NM_003350
*UBE2W NM_018299
*UBE2Z NM_023079
*UBE3A NM_000462
*UBE3B NM_130466
*UBE3C NM_014671
*UBE4A NM_004788
*UBE4B NM_006048
*USP10 NM_005153
*USP14 NM_005151
*USP16 NM_006447
*USP19 NM_006677
*USP22 NM_015276
*USP25 NM_013396
*USP27X NM_001145073
*USP33 NM_015017
*USP38 NM_032557
*USP39 NM_006590
*USP4 NM_003363
*USP47 NM_017944
*USP5 NM_003481
*USP7 NM_003470
*USP8 NM_005154
*USP9X NM_001039590 | 1 | Gene expression + Signal Transduction |
By the early 1970s the climate for R&D was again changing.
Government R&D budgets continued to tighten.
The earlier pattern of Fulmer sponsorship, with a large proportion of contracts from UK ministries and government agencies, no longer applied. In 1955 this proportion had been 70% but by 1970 it had fallen to 45%. By 1985 it was to become less than 5%.
Meanwhile, contract R&D was becoming a familiar concept in the UK.
Following Fulmer, many other contract R&D companies had been formed, important examples being Huntingdon Life Sciences(1957) and Cambridge Consultants(1960).
This gave Fulmer opportunities for collaboration but also increased competition.
Fulmer promoted contract R&D by publishing Register of Consulting Scientists and Contract Research Organizations.
In 1971 Lord Rothschild published his report on Government R&D in which a major recommendation was that "applied R&D ... must be done on a customer-contractor basis. The customer says what he wants; the contractor does it (if he can); and the customer pays".
Despite Rothschild's recommendations, government procurement was slow to change. By 1975, leading independent research companies felt that they were not getting a fair share of government R&D contracts and needed a stronger voice. Fulmer joined with six other companies in setting up the Association of Independent Contract Research Organizations (AICRO).
The journal New Scientist published a special supplement on Contract Research in 1974
There were two major developments that intensified competition in Fulmer's market.
Firstly, organizations such as Harwell, which had been fully government funded, were seeking contracts from industry to make good their declining government income.
Secondly by 1969, following the Robbins Report(1963) on higher education, nine completely new universities had been founded and the ten existing Colleges of Advanced Technology had been converted into full universities.
Robbins found that in the existing universities, teachers spent a third of their time on teaching and rather less than a third on research.
He recommended that "The balance between teaching and research in the universities should in general be maintained."
The net effect was a huge expansion of R&D facilities in universities, funded by their block grants, and they were naturally keen to supplement their incomes with contracts using these facilities. | 0 | Metallurgy |
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physiology and behavior. Hormones are required for the correct development of animals, plants and fungi. Due to the broad definition of a hormone (as a signaling molecule that exerts its effects far from its site of production), numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids (e.g. prostaglandins and thromboxanes), steroids (e.g. oestrogen and brassinosteroid), amino acid derivatives (e.g. epinephrine and auxin), protein or peptides (e.g. insulin and CLE peptides), and gases (e.g. ethylene and nitric oxide).
Hormones are used to communicate between organs and tissues. In vertebrates, hormones are responsible for regulating a wide range of processes including both physiological processes and behavioral activities such as digestion, metabolism, respiration, sensory perception, sleep, excretion, lactation, stress induction, growth and development, movement, reproduction, and mood manipulation. In plants, hormones modulate almost all aspects of development, from germination to senescence.
Hormones affect distant cells by binding to specific receptor proteins in the target cell, resulting in a change in cell function. When a hormone binds to the receptor, it results in the activation of a signal transduction pathway that typically activates gene transcription, resulting in increased expression of target proteins. Hormones can also act in non-genomic pathways that synergize with genomic effects. Water-soluble hormones (such as peptides and amines) generally act on the surface of target cells via second messengers. Lipid soluble hormones, (such as steroids) generally pass through the plasma membranes of target cells (both cytoplasmic and nuclear) to act within their nuclei. Brassinosteroids, a type of polyhydroxysteroids, are a sixth class of plant hormones and may be useful as an anticancer drug for endocrine-responsive tumors to cause apoptosis and limit plant growth. Despite being lipid soluble, they nevertheless attach to their receptor at the cell surface.
In vertebrates, endocrine glands are specialized organs that secrete hormones into the endocrine signaling system. Hormone secretion occurs in response to specific biochemical signals and is often subject to negative feedback regulation. For instance, high blood sugar (serum glucose concentration) promotes insulin synthesis. Insulin then acts to reduce glucose levels and maintain homeostasis, leading to reduced insulin levels. Upon secretion, water-soluble hormones are readily transported through the circulatory system. Lipid-soluble hormones must bond to carrier plasma glycoproteins (e.g., thyroxine-binding globulin (TBG)) to form ligand-protein complexes. Some hormones, such as insulin and growth hormones, can be released into the bloodstream already fully active. Other hormones, called prohormones, must be activated in certain cells through a series of steps that are usually tightly controlled. The endocrine system secretes hormones directly into the bloodstream, typically via fenestrated capillaries, whereas the exocrine system secretes its hormones indirectly using ducts. Hormones with paracrine function diffuse through the interstitial spaces to nearby target tissue.
Plants lack specialized organs for the secretion of hormones, although there is spatial distribution of hormone production. For example, the hormone auxin is produced mainly at the tips of young leaves and in the shoot apical meristem. The lack of specialised glands means that the main site of hormone production can change throughout the life of a plant, and the site of production is dependent on the plant's age and environment. | 1 | Gene expression + Signal Transduction |
Phototropins are photoreceptor proteins (more specifically, flavoproteins) that mediate phototropism responses in various species of algae, fungi and higher plants. Phototropins can be found throughout the leaves of a plant. Along with cryptochromes and phytochromes they allow plants to respond and alter their growth in response to the light environment. Phototropins may also be important for the opening of stomata and the movement of chloroplasts. These blue light receptors are seen across the entire green plant lineage. When Phototropins are hit with blue light, they induce a signal transduction pathway that alters the plant cells' functions in different ways.
Phototropins are part of the phototropic sensory system in plants that causes various environmental responses in plants. Phototropins specifically will cause stems to bend towards light and stomata to open. Phototropins have been shown to impact the movement of chloroplast inside the cell. In addition phototropins mediate the first changes in stem elongation in blue light prior to cryptochrome activation. Phototropin is also required for blue light mediated transcript destabilization of specific mRNAs in the cell. They are present in the guard cell. | 1 | Gene expression + Signal Transduction |
Moreover, Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMKII) is best recognized for its roles in the brain, particularly in the neocortex and hippocampal regions because it serves as a ubiquitous mediator of cellular Ca2+ signals. CaMKII is abundant in the nervous system, mainly concentrated in the synapses in the nerve cells. Indeed, CaMKII has been definitively identified as a key regulator of cognitive processes, such as learning, and neural plasticity. The first concrete experimental evidence for the long-assumed function of CaMKII in memory storage was demonstrated
While Ca2+/CaM binding stimulates CaMKII activity, Ca2+-independent autonomous CaMKII activity can also be produced by a number of other processes. CaMKII becomes active by autophosphorylating itself upon Ca2+/calmodulin binding. CaMKII is still active and phosphorylates itself even after Ca2+ is cleaved; as a result, the brain stores long-term memories using this mechanism. Nevertheless, when the CaMKII enzyme is dephosphorylated by a phosphatase enzyme, it becomes inactive, and memories are lost. Hence, CaMKII plays a vital role in both the induction and maintenance of LTP. | 1 | Gene expression + Signal Transduction |
Binding of Ca by the EF-hands causes an opening of the N- and C-domains, which exposes hydrophobic target-binding surfaces. These surfaces interact with complementary nonpolar segments on target proteins, typically consisting of groups of bulky hydrophobic amino acids separated by 10–16 polar and/or basic amino acids. The flexible central domain of calmodulin allows the protein to wrap around its target, although alternate modes of binding are known. "Canonical" targets of calmodulin, such as myosin light-chain kinases and CaMKII, bind only to the Ca-bound protein, whereas some proteins, such as NaV channels and IQ-motif proteins, also bind to calmodulin in the absence of Ca. Binding of calmodulin induces conformational rearrangements in the target protein via "mutually induced fit", leading to changes in the target protein's function.
Calcium binding by calmodulin exhibits considerable cooperativity, making calmodulin an unusual example of a monomeric (single-chain) cooperative binding protein. Furthermore, target binding alters the binding affinity of calmodulin toward Ca ions, which allows for complex allosteric interplay between Ca and target binding interactions. This influence of target binding on Ca affinity is believed to allow for Ca activation of proteins that are constitutively bound to calmodulin, such as small-conductance Ca-activated potassium (SK) channels.
Although calmodulin principally operates as a Ca binding protein, it also coordinates other metal ions. For example, in the presence of typical intracellular concentrations of Mg (0.5–1.0 mM) and resting concentrations of Ca (100 nM), calmodulins Ca binding sites are at least partially saturated by Mg. This Mg is displaced by the higher concentrations of Ca generated by signaling events. Similarly, Ca may itself be displaced by other metal ions, such as the trivalent lanthanides, that associate with calmodulins binding pockets even more strongly than Ca. Though such ions distort calmodulins structure and are generally not physiologically relevant due to their scarcity in vivo', they have nonetheless seen wide scientific use as reporters of calmodulin structure and function. | 1 | Gene expression + Signal Transduction |
The exceptional yield strength of nanocrystalline metals is due to grain boundary strengthening, as grain boundaries are extremely effective at blocking the motion of dislocations. Yielding occurs when the stress due to dislocation pileup at a grain boundary becomes sufficient to activate slip of dislocations in the adjacent grain. This critical stress increases as the grain size decreases, and these physics are empirically captured by the Hall-Petch relationship,
where is the yield stress, is a material-specific constant that accounts for the effects of all other strengthening mechanisms, is a material-specific constant that describes the magnitude of the metal's response to grain size strengthening, and is the average grain size. Additionally, because nanocrystalline grains are too small to contain a significant number of dislocations, nanocrystalline metals undergo negligible amounts of strain-hardening, and nanocrystalline materials can thus be assumed to behave with perfect plasticity.
As the grain size continues to decrease, a critical grain size is reached at which intergranular deformation, i.e. grain boundary sliding, becomes more energetically favorable than intragranular dislocation motion. Below this critical grain size, often referred to as the “reverse” or “inverse” Hall-Petch regime, any further decrease in the grain size weakens the material because an increase in grain boundary area results in increased grain boundary sliding. Chandross & Argibay modeled grain boundary sliding as viscous flow and related the yield strength of the material in this regime to material properties as
where is the enthalpy of fusion, is the atomic volume in the amorphous phase, is the melting temperature, and is the volume fraction of material in the grains vs the grain boundaries, given by , where is the grain boundary thickness and typically on the order of 1 nm. The maximum strength of a metal is given by the intersection of this line with the Hall-Petch relationship, which typically occurs around a grain size of = 10 nm for BCC and FCC metals.
Due to the large amount of interfacial energy associated with a large volume fraction of grain boundaries, nanocrystalline metals are thermally unstable. In nanocrystalline samples of low-melting point metals (i.e. aluminum, tin, and lead), the grain size of the samples was observed to double from 10 to 20 nm after 24 hours of exposure to ambient temperatures. Although materials with higher melting points are more stable at room temperatures, consolidating nanocrystalline feedstock into a macroscopic component often requires exposing the material to elevated temperatures for extended periods of time, which will result in coarsening of the nanocrystalline microstructure. Thus, thermally stable nanocrystalline alloys are of considerable engineering interest. Experiments have shown that traditional microstructural stabilization techniques such as grain boundary pinning via solute segregation or increasing solute concentrations have proven successful in some alloy systems, such as Pd-Zr and Ni-W. | 0 | Metallurgy |
Recent studies have reported the ability of drug-resistant cancer cells to acquire mitogenic signals from previously neglected autocrine loops, causing tumor recurrence.
For example, despite widespread expression of epidermal growth factor receptors (EGFRs) and EGF family ligands in non-small-cell lung cancer (NSCLC), EGFR-specific tyrosine kinase inhibitors such as gefitinib have shown limited therapeutic success. This resistance is proposed to be because autocrine growth signaling pathways distinct from EGFR are active in NSCLC cells. Gene expression profiling revealed the prevalence of specific fibroblast growth factors (FGFs) and FGF receptors in NSCLC cell lines, and found that FGF2, FGF9 and their receptors encompass a growth factor autocrine loop that is active in a subset of gefitinib-resistant NSCLC cell lines.
In breast cancer, the acquisition of tamoxifen resistance is another major therapeutic problem. It has been shown that phosphorylation of STAT3 and RANTES expression are increased in response to tamoxifen in human breast cancer cells. In a recent study, one group showed that STAT3 and RANTES contribute to the maintenance of drug resistance by upregulating anti-apoptotic signals and inhibiting caspase cleavage. These mechanisms of STAT3-RANTES autocrine signaling suggest a novel strategy for management of patients with tamoxifen-resistant tumors. | 1 | Gene expression + Signal Transduction |
It is possible to perform a CD4 co-receptor blockade, using antibodies, in order to lower T cell activation and counteract autoimmune disorders. This blockade appears to elicit a "dominant" effect, that is to say, once blocked, the T cells do not regain their ability to become active. This effect then spreads to native T cells which then switch to a CD4+CD25+GITR+FoxP3+ T regulatory phenotype. | 1 | Gene expression + Signal Transduction |
The modern X-ray fluorescence (XRF) is also a non-destructive technique that is suitable for normal assaying requirements. It typically has an accuracy of 2 to 5 parts per thousand and is well-suited to relatively flat and large surfaces. It is a quick technique taking about three minutes, and the results can be automatically printed out by computer.
One process for X-ray fluorescence assay involves melting the material in a furnace and stirring to make a homogeneous mix. Following this, a sample is taken from the centre of the molten sample. Samples are typically taken using a vacuum pin tube. The sample is then tested by X-ray fluorescence spectroscopy. Metallurgical assay is typically completed in this way to ensure that an accurate assay is performed. | 0 | Metallurgy |
In the old days of traditional manufacturing, steel and other metals arrived at factories in an untreated and unpainted state. Companies would fabricate and paint or treat the metal components of their product before assembly. This was costly, time-consuming, and environmentally harmful. The coil coating process was pioneered in the 1930s for painting, coating and pre-treating large coils of metals before they arrived at a manufacturing facility. The venetian blind industry was the first to utilize pre-painted metal. | 0 | Metallurgy |
Diffusion hardening is a process used in manufacturing that increases the hardness of steels. In diffusion hardening, diffusion occurs between a steel with a low carbon content and a carbon-rich environment to increase the carbon content of the steel and ultimately harden the workpiece. Diffusion only happens through a small thickness of a piece of steel (about 2.5 μm to 1.5 mm), so only the surface is hardened while the core maintains its original mechanical properties. Heat treating may be performed on a diffusion hardened part to increase the hardness of the core as desired, but in most cases in which diffusion hardening is performed, it is desirable to have parts with a hard outer shell and a more ductile inside. Heat treating and quenching is a more efficient process if hardness is desired throughout the whole part. In the case of manufacturing parts subject to large amounts of wear, such as gears, the non-uniform properties acquired through diffusion hardening are desired. Through this process, gears obtain a hard wear-resistant outer shell but maintain their softer and more impact-resistant core. | 0 | Metallurgy |
PRKAR1A has been shown to interact with:
* AKAP10,
* AKAP1,
* AKAP4,
* ARFGEF1,
* ARFGEF2,
* Grb2,
* MYO7A,
* PRKAR1B, and
* UBE2M. | 1 | Gene expression + Signal Transduction |
The alkali metal polysulfides arise by treatment of a solution of sulfide, e.g. sodium sulfide, with elemental sulfur:
In some cases, these anions have been obtained as organic salts, which are soluble in organic solvents.
The energy released in the reaction of sodium and elemental sulfur is the basis of battery technology. The sodium–sulfur battery and the lithium–sulfur battery require high temperatures to maintain liquid polysulfide and -conductive membranes that are unreactive toward sodium, sulfur, and sodium sulfide.
Polysulfides are ligands in coordination chemistry. Examples of transition metal polysulfido complexes include titanocene pentasulfide|, , and . Main group elements also form polysulfides. | 0 | Metallurgy |
Graham Charles Wood FRS (6 February 1934—4 November 2016) was an English corrosion scientist.
Born in Farnborough, he went on to study metallurgy at Cambridge. Following postdoctoral work at Cambridge, he moved to Manchester, where his career in corrosion science would be based, starting at the Manchester College of Science and Technology (now the University of Manchester) where he joined the Department of Chemical Engineering as a lecturer in corrosion science. In 1972 he established and led the Corrosion and Protection Centre at UMIST (University of Manchester Institute of Science and Technology) as professor of corrosion science. In 1973 he helped to establish a consulting organisation, Corrosion and Protection Centre Industrial Service (CAPCIS – now part of Intertek).
Graham served terms as President of the Corrosion and Protection Association and the Institution of Corrosion Science and Technology ([https://www.icorr.org/ Institute of Corrosion]), and chaired the National Council for Corrosion Societies. He also served as a UK representative on the International Corrosion Council for 15 years, for which he also served as vice-chair and chair.
At UMIST, he held several administerial roles, including vice-principal for academic development, dean, and pro-vice chancellor.
He was elected Fellow of the Royal Academy of Engineering in 1990, and Fellow of the Royal Society in 1997. | 0 | Metallurgy |
Embrittlement is a series complex mechanism that is not completely understood. The mechanisms can be driven by temperature, stresses, grain boundaries, or material composition. However, by studying the embrittlement process, preventative measures can be put in place to mitigate the effects. There are several ways to study the mechanisms. During metal embrittlement (ME), crack-growth rates can be measured. Computer simulations can also be used to enlighten the mechanisms behind embrittlement. This is helpful for understanding hydrogen embrittlement (HE), as the diffusion of hydrogen through materials can be modeled. The embrittler does not play a role in final fracture; it is mostly responsible for crack propagation. Cracks must first nucleate. Most embrittlement mechanisms can cause fracture transgranularly or intergranularly. For metal embrittlement, only certain combinations of metals, stresses, and temperatures are susceptible. This is contrasted to stress-corrosion cracking where virtually any metal can be susceptible given the correct environment. Yet this mechanism is much slower than that of liquid metal embrittlement (LME), suggesting that it directs a flow of atoms both towards and away from the crack. For neutron embrittlement, the main mechanism is collisions within the material from the fission byproducts. | 0 | Metallurgy |
Transcription factor II E (TFE) is one of several general transcription factors that make up the RNA polymerase II preinitiation complex. It is a tetramer of two alpha and two beta chains and interacts with TAF6/TAFII80, ATF7IP, and varicella-zoster virus IE63 protein.
TFE recruits TFH to the initiation complex and stimulates the RNA polymerase II C-terminal domain kinase and DNA-dependent ATPase activities of TFH. Both TFH and TFE are required for promoter clearance by RNA polymerase. Transcription factor II E is encoded by the GTF2E1 and GTF2E2 genes. TFE is thought to be involved in DNA melting at the promoter: it contains a zinc ribbon motif that can bind single stranded DNA. | 1 | Gene expression + Signal Transduction |
The range of applications for SMAs has grown over the years, a major area of development being dentistry. One example is the prevalence of dental braces using SMA technology to exert constant tooth-moving forces on the teeth; the nitinol archwire was developed in 1972 by orthodontist George Andreasen. This revolutionized clinical orthodontics. Andreasen's alloy has a patterned shape memory, expanding and contracting within given temperature ranges because of its geometric programming.
Harmeet D. Walia later utilized the alloy in the manufacture of root canal files for endodontics. | 0 | Metallurgy |
Unsuccessful transfer or abortive transfer is any bacterial DNA transfer from donor cells to recipient cells that fails to survive transduction and conjugation. In all cases, the transferred fragment could be diluted during the proliferation phase. Failures in the integration of the transferred DNA in the genetic material of the recipient cells may be due to:
*Failure of the incoming DNA to form a circular molecule;
*Post-circularisation, the circular molecule is wrong for maintenance, making this transfer occurs as plasmids. Genes that are located on the corresponding part of the DNA can express in the recipient cells. | 1 | Gene expression + Signal Transduction |
Air pollutants generated by aluminium smelters include carbonyl sulfide, hydrogen fluoride, polycyclic compounds, lead, nickel, manganese, polychlorinated biphenyls, and mercury. Copper smelter emissions include arsenic, beryllium, cadmium, chromium, lead, manganese, and nickel. Lead smelters typically emit arsenic, antimony, cadmium and various lead compounds. | 0 | Metallurgy |
In molecular biology, a termination factor is a protein that mediates the termination of RNA transcription by recognizing a transcription terminator and causing the release of the newly made mRNA. This is part of the process that regulates the transcription of RNA to preserve gene expression integrity and are present in both eukaryotes and prokaryotes, although the process in bacteria is more widely understood. The most extensively studied and detailed transcriptional termination factor is the Rho (ρ) protein of E. coli. | 1 | Gene expression + Signal Transduction |
The Wnt signaling pathways are initiated by the binding of the Wnt ligand to the Fz receptor. There are three different molecular pathways downstream of the Wnt/Fz interaction. The majority of research has focused on the Wnt/β-catenin pathway (also known as the "canonical" Wnt pathway), which manages cell fate determination by regulating gene expression. The Wnt/Ca and Wnt/polarity pathways are known as the "non-canonical pathways". The decision of which pathway is activated most likely depends on which Wnt ligand and Fz receptor are present, as well as the cellular context. Nineteen Wnt ligands and ten different members of the Fz seven-transmembrane receptor family have been described in the human genome. As a result, a large variety of responses could be initiated from the Wnt/Fz interactions.
The Wnt/β-catenin pathway starts with the binding of Wnt to a receptor complex encompassing a Fz receptor and LRP co-receptor. After Wnt binds, an intracellular protein named Dishevelled (Dvl) is activated via phosphorylation. β-catenin degradation complexes in the cytoplasm are composed of adenomatous polyposis coli (APC), glycogen synthase kinase 3β (GSK3β) and Axin. APC promotes the degradation of β-catenin by increasing the affinity of the degradation complex to β-catenin. Axin is a scaffolding protein which holds the degradation complex together. The activated Dvl associates with Axin and prevents GSK3β and casein kinase 1α (CK1α) from phosphorylating critical substrates, such as β-catenin. Phosphorylation of β-catenin marks the protein for ubiquitylation and rapid degradation by proteasomes. Thus, the binding of Wnt to the receptor results in a non-phosphorylated form of β-catenin which localizes to the nucleus and, after displacing the Groucho corepressor protein, forms a complex with Tcf/Lef transcription factors and co-activators (such as CREB binding protein) and induces the expression of downstream target genes.
β-catenin is actively stabilized in over 50% of breast cancers and its nuclear localization correlates with poor patient prognosis. Several target genes of the Wnt signaling pathway, such as cyclin D1, are activated in a significant proportion of breast tumours. It has been shown that SFRP1 transcription can be driven by B-catenin in normal intestinal epithelial cells. Neoplastic epithelial cells were treated with lithium chloride, which inhibits GSK3B and thus stabilizes B-catenin. Lithium chloride is widely used to mimic Wnt signaling. Rather than suppressing SFRP1 expression, B-catenin/TCF activity was associated with the induction of SFRP1. This is consistent with a negative feedback response restricting the exposure of a normal cell to a prolonged Wnt growth factor signal.
Hedgehog signaling in the intestinal epithelium represses the canonical Wnt signaling to restrict expression of Wnt target genes to stem or progenitor cells. It was thought that the Hedgehog signaling pathway does this via the induction of the secreted-type Wnt inhibitor. Katoh et al. searched for the GLI-binding site within the promoter region of Wnt inhibitor genes. GLI are transcription factors that activate the transcription of Hedgehog target genes. The GLI-binding site was identified within the 5’-flanking promoter region of the human SFRP1 gene. The GLI-binding site was conserved among promoter regions of mammalian SFRP1 orthologs. These facts indicate that the SFRP1 gene was identified as the evolutionarily conserved target of the Hedgehog-GLI signaling pathway. SFRP1 was found to be expressed in mesenchymal cells. Hedgehog is secreted from differentiated epithelial cells to induce SFRP1 expression in mesenchymal cells, which keeps differentiated epithelial cells away from the effect of canonical Wnt signaling. Thus, SFRP1 is most likely the Hedgehog target to confine canonical Wnt signaling within stem or progenitor cells. Epigenetic CpG hypermethylation of the SFRP1 promoter during chronic persistent inflammation and aging leads to the occurrence of gastrointestinal cancers, such as colorectal cancer and gastric cancer, through the breakdown of Hedgehog-dependent Wnt signal inhibition. | 1 | Gene expression + Signal Transduction |
Mice with truncated EpoR are viable, which suggests Jak2 activity is sufficient to support basal erythropoiesis by activating the necessary pathways without phosphotyrosine docking sites being needed. EpoR-H form of EpoR truncation contains the first, and, what can be argued, the most important tyrosine 343 that serves as a docking site for the Stat5 molecule, but lacks the rest of the cytoplasmic tail. These mice exhibit elevated erythropoiesis consistent with the idea that phosphatase recruitment (and therefore the shutting down of signaling) is aberrant in these mice.
The EpoR-HM receptor also lacks the majority of the cytoplasmic domain, and contains the tyrosine 343 that was mutated to phenylalanine, making it unsuitable for efficient Stat5 docking and activation. These mice are anemic and show poor response to hypoxic stress, such as phenylhydrazine treatment or erythropoietin injection.
EpoR knockout mice have defects in heart, brain and the vasculature. These defects may be due to blocks in RBC formation and thus insufficient oxygen delivery to developing tissues because mice engineered to express Epo receptors only in erythroid cells develop normally. | 1 | Gene expression + Signal Transduction |
Corrosion in space has the highest impact on spacecraft with moving parts. Early satellites tended to develop problems with seizing bearings. Now the bearings are coated with a thin layer of gold.
Different materials resist corrosion in space differently. For example, aluminium is slowly eroded by atomic oxygen, while gold and platinum are highly corrosion-resistant. Gold-coated foils and thin layers of gold on exposed surfaces are therefore used to protect the spacecraft from the harsh environment. Thin layers of silicon dioxide deposited on the surfaces can also protect metals from the effects of atomic oxygen; e.g., the Starshine 3 satellite aluminium front mirrors were protected that way. However, the protective layers are subject to erosion by micrometeorites.
Silver builds up a layer of silver oxide, which tends to flake off and has no protective function; such gradual erosion of silver interconnects of solar cells was found to be the cause of some observed in-orbit failures.
Many plastics are considerably sensitive to atomic oxygen and ionizing radiation. Coatings resistant to atomic oxygen are a common protection method, especially for plastics. Silicone-based paints and coatings are frequently employed, due to their excellent resistance to radiation and atomic oxygen. However, the silicone durability is somewhat limited, as the surface exposed to atomic oxygen is converted to silica which is brittle and tends to crack. | 0 | Metallurgy |
It is thought that erythroid differentiation is primarily dependent on the presence and induction of erythroid transcriptional factors such as GATA-1, FOG-1 and EKLF, as well as the suppression of myeloid/lymphoid transcriptional factors such as PU.1. Direct and significant effects of EpoR signaling specifically upon the induction of erythroid-specific genes such as beta-globin, have been mainly elusive. It is known that GATA-1 can induce EpoR expression. In turn, EpoR's PI3-K/AKT signaling pathway augments GATA-1 activity. | 1 | Gene expression + Signal Transduction |
Roses metal, Rose metal or Roses alloy is a fusible alloy with a low melting point.
Rose's metal consists of 50% bismuth, 25–28% lead and 22–25% tin. Its melting point is between . The alloy does not appreciably contract or expand on solidification, this characteristic being a function of its bismuth percentage, but does slightly contract on cooling. | 0 | Metallurgy |
Although the problem was first found in brass, any alloy containing copper will be susceptible to the problem. It includes copper itself (as used in pipe for example), bronzes and other alloys with a significant copper content. Like all problems with hairline cracks, detection in the early stages of attack is difficult, but the characteristic blue coloration may give a clue to attack. Microscopic inspection will often reveal the cracks, and x-ray analysis using the EDX facility on the scanning electron microscope or SEM should reveal the presence of elemental nitrogen from ammoniacal traces. | 0 | Metallurgy |
In high-temperature metal joining processes (welding, brazing and soldering), fluxes are nearly inert at room temperature, but become strongly reducing at elevated temperatures, preventing oxidation of the base and filler materials. The role of flux is typically dual: dissolving the oxides already present on the metal surface to facilitate wetting by molten metal, and acting as an oxygen barrier by coating the hot surface, preventing oxidation.
For example, tin-lead solder attaches very well to copper metal, but poorly to its oxides, which form quickly at soldering temperatures. By preventing the formation of metal oxides, flux enables the solder to adhere to the clean metal surface, rather than forming beads, as it would on an oxidized surface. | 0 | Metallurgy |
When applied to existing constructions, the lifetime can be extended considerably. If no macroscopically visible cracks are present, HiFIT is a very suitable remediation tool.
With timely remediation of existing structures there is practically no difference to the life of new treated welds. This gives the potential to use existing constructions far beyond the planned lifetime. The HiFIT-method is used very efficient e.g. at highway bridges in steel hollow box-section design on the fly. Costs for reconstruction are low compared to conventional methods. In the commercial vehicle industry and other industries highly stressed welds on existing and new structures are treated with HiFIT to extend lifetime successfully. | 0 | Metallurgy |
It has been shown previously that OMgp (oligodendrocyte myelin glycoprotein) clusters at nodes of Ranvier and may regulate paranodal architecture, node length and axonal sprouting at nodes. However, a follow-up study showed that the antibody used previously to identify OMgp at nodes crossreacts with another node-enriched component versican V2 and that OMgp is not required for the integrity of nodes and paranodes, arguing against the previously reported localization and proposed functions of OMgp at nodes. | 1 | Gene expression + Signal Transduction |
Understanding the mechanical properties of Heusler compounds is paramount for temperature-sensitive applications (e.g. thermoelectrics) for which some sub-classes of Heusler compounds are used. However, experimental studies are rarely encountered in literature. In fact, the commercialization of these compounds is limited by the materials ability to undergo intense, repetitive thermal cycling and resist cracking from vibrations. An appropriate measure for crack resistance is the materials toughness, which typically scales inversely with another important mechanical property: the mechanical strength. In this section, we highlight existing experimental and computational studies on the mechanical properties of Heusler alloys. Note that the mechanical properties of such a compositionally-diverse class of materials is expectedly dependent on the chemical composition of the alloys themselves, and therefore trends in mechanical properties are difficult to identify without a case-by-case study.
The elastic modulus values of half-Heusler alloys range from 83 to 207 GPa, whereas the bulk modulus spans a tighter range from 100 GPa in HfNiSn to 130 GPa in TiCoSb. A collection of various density functional theory (DFT) calculations show that half-Heusler compounds are predicted to have a lower elastic, shear, and bulk modulus than in quaternary-, full-, and inverse-Hausler alloys. DFT also predicts a decrease in elastic modulus with temperature in NiXAl (X=Sc, Ti, V), as well as an increase in stiffness with pressure. The decrease in modulus with respect to temperature is also observed in TiNiSn, ZrNiSn, and HfNiSn, where ZrNiSn has the highest modulus and Hf has the lowest. This phenomenon can be explained by the fact that the elastic modulus decreases with increasing interatomic separation: as temperature increases, the atomic vibrations also increase, resulting in a larger equilibrium interatomic separation.
The mechanical strength is also rarely studied in Heusler compounds. One study has shown that, in off-stoichiometric NiMnIn, the material reaches a peak strength of 475 MPa at 773 K, which drastically reduces to below 200 MPa at 973 K. In another study, a polycrystalline Heusler alloy composed of the Ni-Mn-Sn ternary composition space was found to possess a peak compressive strength of about 2000 MPa with plastic deformation up to 5%. However, the addition of Indium to the Ni-Mn-Sn ternary alloy not only increases the porosity of the samples, but it also reduces the compressive strength to 500 MPa. It is unclear from the study what percentage of the porosity increase from the indium addition reduces the strength. Note that this is opposite to the outcome expected from solid solution strengthening, where adding indium to the ternary system slows dislocation movement through dislocation-solute interaction and subsequently increases the material's strength.
The fracture toughness can also be tuned with composition modifications. For example, the average toughness of Ti(Zr, Hf)NiSn ranges from 1.86 MPa m to 2.16 MPa m, increasing with Zr/Hf content. The preparation of samples may affect the measured fracture toughness however, as elaborated by O’Connor et al. In their study, samples of TiHfCoIrSbSn were prepared using three different methods: a high-temperature solid state reaction, high-energy ball milling, and a combination of both. The study found higher fracture toughness in samples prepared without a high-energy ball milling step of 2.7 MPa m to 4.1 MPa m, as opposed to samples that were prepared with ball milling of 2.2 MPa m to 3.0 MPa m. Fracture toughness is sensitive to inclusions and existing cracks in the material, so it is as expected dependent on the sample preparation. | 0 | Metallurgy |
Activated Ras then activates the protein kinase activity of a RAF kinase. The RAF kinase phosphorylates and activates a MAPK/ERK Kinase (MEK1 or MEK2). The MEK phosphorylates and activates a mitogen-activated protein kinase (MAPK).
RAF and MAPK/ERK are both serine/threonine-specific protein kinases. MEK is a serine/tyrosine/threonine kinase.
In a technical sense, RAF, MEK, and MAPK are all mitogen-activated kinases, as is MNK (see below). MAPKs were originally called "extracellular signal-regulated kinases" (ERKs) and "microtubule associated protein kinases" (MAPKs). One of the first proteins known to be phosphorylated by ERK was a microtubule-associated protein (MAP). As discussed below, many additional targets for phosphorylation by MAPK were later found, and the protein was renamed "mitogen-activated protein kinase" (MAPK). The series of kinases from RAF to MEK to MAPK is an example of a protein kinase cascade. Such series of kinases provide opportunities for feedback regulation and signal amplification. | 1 | Gene expression + Signal Transduction |
Titanium powder metallurgy (P/M) offers the possibility of creating net shape or near net shape parts without the material loss and cost associated with having to machine intricate components from wrought billet. Powders can be produced by the blended elemental technique or by pre-alloying and then consolidated by metal injection moulding, hot isostatic pressing, direct powder rolling or laser engineered net shaping. | 0 | Metallurgy |
RNA-induced transcriptional silencing (RITS) is a form of RNA interference by which short RNA molecules – such as small interfering RNA (siRNA) – trigger the downregulation of transcription of a particular gene or genomic region. This is usually accomplished by posttranslational modification of histone tails (e.g. methylation of lysine 9 of histone H3) which target the genomic region for heterochromatin formation. The protein complex that binds to siRNAs and interacts with the methylated lysine 9 residue of histones H3 (H3K9me2) is the RITS complex.
RITS was discovered in the fission yeast Schizosaccharomyces pombe, and has been shown to be involved in the initiation and spreading of heterochromatin in the mating-type region and in centromere formation. The RITS complex in S. pombe contains at least a piwi domain-containing RNase H-like argonaute, a chromodomain protein Chp1, and an argonaute interacting protein Tas3 which can also bind to Chp1, while heterochromatin formation has been shown to require at least argonaute and an RNA-dependent RNA polymerase. Loss of these genes in S. pombe results in abnormal heterochromatin organization and impairment of centromere function, resulting in lagging chromosomes on anaphase during cell division. | 1 | Gene expression + Signal Transduction |
The following is a list of human hepatocyte nuclear factors (see also boxes to the right for additional information about these proteins): | 1 | Gene expression + Signal Transduction |
The first recorded experimental work in copper was conducted by Cushing in 1894 in order to demonstrate that copper plate found in Hopewell mounds in Ohio could have been produced by the Hopewell people and not come from European trade. In his experiments, Cushing used antler and stone tools to cut out sheets of copper and puncture round holes in them through a method of pressure and grinding. In addition to the copper sheet experiments, Cushing also conducted smelting experiments reconstructed from finding at Salado Valley, Arizona pueblo excavations to reproduce copper artifacts. | 0 | Metallurgy |
Moreover, because the assembly of the full-length gene product relies on the efficient and specific alignment of long single stranded oligonucleotides, critical parameters for synthesis success include extended sequence regions comprising secondary structures caused by inverted repeats, extraordinary high or low GC-content, or repetitive structures. Usually these segments of a particular gene can only be synthesized by splitting the procedure into several consecutive steps and a final assembly of shorter sub-sequences, which in turn leads to a significant increase in time and labor needed for its production.
The result of a gene synthesis experiment depends strongly on the quality of the oligonucleotides used. For these annealing based gene synthesis protocols, the quality of the product is directly and exponentially dependent on the correctness of the employed oligonucleotides. Alternatively, after performing gene synthesis with oligos of lower quality, more effort must be made in downstream quality assurance during clone analysis, which is usually done by time-consuming standard cloning and sequencing procedures.
Another problem associated with all current gene synthesis methods is the high frequency of sequence errors because of the usage of chemically synthesized oligonucleotides. The error frequency increases with longer oligonucleotides, and as a consequence the percentage of correct product decreases dramatically as more oligonucleotides are used.
The mutation problem could be solved by shorter oligonucleotides used to assemble the gene. However, all annealing based assembly methods require the primers to be mixed together in one tube. In this case, shorter overlaps do not always allow precise and specific annealing of complementary primers, resulting in the inhibition of full length product formation.
Manual design of oligonucleotides is a laborious procedure and does not guarantee the successful synthesis of the desired gene. For optimal performance of almost all annealing based methods, the melting temperatures of the overlapping regions are supposed to be similar for all oligonucleotides. The necessary primer optimisation should be performed using specialized oligonucleotide design programs. Several solutions for automated primer design for gene synthesis have been presented so far. | 1 | Gene expression + Signal Transduction |
The integrated stress response is a cellular stress response conserved in eukaryotic cells that downregulates protein synthesis and upregulates specific genes in response to internal or environmental stresses. | 1 | Gene expression + Signal Transduction |
Using the model organism Drosophila melanogaster, data has been compiled regarding the genomic information and sequencing of this organism. A prediction model exists in which a researcher can upload his or her genomic information and use a splice site prediction database to gather information about where the splice sites could be located. [http://www.fruitfly.org/about/index.html The Berkeley Drosophila Project] can be used to incorporate this research, as well as annotate high quality euchromatic data. The splice site predictor can be a great tool for researchers studying human disease in this model organism.
Splice site mutations can be analyzed using information theory. | 1 | Gene expression + Signal Transduction |
SMRT (silencing mediator of retinoic acid and thyroid hormone receptor), also known as NCoR2, is an alternatively spliced SRC-1(steroid receptor coactivator-1). It is negatively and positively affected by MAPKKK (mitogen activated protein kinase kinase kinase) and casein kinase 2 phosphorylation, respectively. SMRT has two major mechanisms: first, similar to NCoR, SMRT also recruits class I histone deacetylases through SIN3 and directly binds to class II histone deacetylases. Second, it binds and sequesters components of the general transcriptional machinery, such as transcription factor II B. | 1 | Gene expression + Signal Transduction |
Besides trying to re-activate the tumor suppressive function of pRb, one other distinct approach to treat dysregulated pRb pathway cancers is to take advantage of certain cellular consequences induced by pRb loss. It has been shown that E2F stimulates expression of pro-apoptotic genes in addition to G1/S transition genes, however, cancer cells have developed defensive signaling pathways that protect themselves from death by deregulated E2F activity. Development of inhibitors of these protective pathways could thus be a synthetically lethal method to kill cancer cells with overactive E2F.
In addition, it has been shown that the pro-apoptotic activity of p53 is restrained by the pRb pathway, such that pRb deficient tumor cells become sensitive to p53 mediated cell death. This opens the door to research of compounds that could activate p53 activity in these cancer cells and induce apoptosis and reduce cell proliferation. | 1 | Gene expression + Signal Transduction |
Archaeologist George Eogan, in his study of Bronze Age gold-working, noted that very few Bronze Age gold artefacts had been discovered through "controlled archaeological investigation", with the majority instead having been unearthed "by chance", as a result of "agricultural activities or peat-cutting". In the 21st century, metal detectorists have become important, for example with the important Shropshire bulla, found in 2018. | 0 | Metallurgy |
The TRIM family is split into two groups that differ in domain structure and genomic organization:
* Group 1 members possess a variety of C-terminal domains, and are represented in both vertebrate and invertebrates
* Group 2 is absent in invertebrates, possess a C-terminal SPRY domain
Members of the family include:
* Group 1
** PHD-BROMO domain containing: TRIM24 (TIF1α), TRIM28 (TIF1β), TRIM33 (TIF1γ)– act as corepressors
** 1-10: TRIM1, TRIM2, TRIM3, TRIM8, TRIM9
** 11-20: TRIM12, TRIM13, TRIM14, TRIM16, TRIM18, TRIM19
** 21-30: TRIM23, TRIM25, TRIM29, TRIM30
** 31-40: TRIM32, TRIM36, TRIM37
** 41-50: TRIM42, TRIM44, TRIM45, TRIM46, TRIM47
** 51-60: TRIM51, TRIM53, TRIM54, TRIM55, TRIM56, TRIM57, TRIM59
** 61-70: TRIM62, TRIM63, TRIM65, TRIM66, TRIM67, TRIM69, TRIM70
** 71-75: TRIM71
* Group 2
** 1-10: TRIM4, TRIM5, TRIM6, TRIM7, TRIM10
** 11-20: TRIM11, TRIM12, TRIM15, TRIM17, TRIM20
** 21-30: TRIM21, TRIM22, TRIM26, TRIM27, TRIM30
** 31-40: TRIM31, TRIM34, TRIM35, TRIM38, TRIM39, TRIM40
** 41-50: TRIM41, TRIM43, TRIM48, TRIM49, TRIM50
** 51-60: TRIM51, TRIM52, TRIM53, TRIM57, TRIM58, TRIM60
** 61-70: TRIM61, TRIM64, TRIM68, TRIM69, TRIM70
** 71-75: TRIM72, TRIM73, TRIM74, TRIM75 | 1 | Gene expression + Signal Transduction |
Williams commenced lecturing at McGill University in 1960, and was selected to be the Chairman of the Department of Mining and Metallurgy in 1966. As Chairman, he was instrumental in expanding the department at a time when only six degree programs in Metallurgical Engineering were being offered in Canadian universities, among which McGill's department was the oldest. During his tenure, seven new faculty members were added to the department, with the new faculty primarily focusing its research on extractive (hydro and pyro), process and physical metallurgy. Ties between the department and Canadian industries were also strengthened during this time. Throughout his career, Williams conducted research on a variety of topics ranging from esoteric studies of grain shape to the practical aspects of abrasion resistant cast irons for mineral comminution. Williams held the position of Chairman until 1980, and retired from teaching in 1992. From 1972 to 1973, he was President of the Metallurgical Society of CIM.
As a specialist in failure analysis, Williams was consulted to investigate numerous engineering failures including such notable events as the 1965 LaSalle Heights disaster, the Mississauga train derailment of 1979, and the crash of Quebecair Flight 255. From 1990 to 2000, he was a consultant metallurgist for Via Rail. Williams also served as an expert witness in about 40 court cases in Canada and the United States, and was twice appointed Judge's Expert by justices James K. Hugessen and Antonio Lamar respectively. | 0 | Metallurgy |
The mined ore is usually crushed into small chunks and heaped on an impermeable plastic or clay lined leach pad where it can be irrigated with a leach solution to dissolve the valuable metals. While sprinklers are occasionally used for irrigation, more often operations use drip irrigation to minimize evaporation, provide more uniform distribution of the leach solution, and avoid damaging the exposed mineral. The solution then percolates through the heap and leaches both the target and other minerals. This process, called the "leach cycle," generally takes from one or two months for simple oxide ores (e.g. most gold ores) to two years for nickel laterite ores. The leach solution containing the dissolved minerals is then collected, treated in a process plant to recover the target mineral and in some cases precipitate other minerals, and recycled to the heap after reagent levels are adjusted. Ultimate recovery of the target mineral can range from 30% of contained run-of-mine dump leaching sulfide copper ores to over 90% for the ores that are easiest to leach, some oxide gold ores.
The essential questions to address during the process of the heap leaching are:
* Can the investment of crushing the ore be justified by the potential increase in recovery and rate of recovery?
* How should the concentration of acid be altered over time in order to produce a solution that can be economically treated?
* How does the form of a heap affect the recovery and solution grade?
* Under any given set of circumstances, what type of recovery can be expected before the leach solution quality drops below a critical limit?
* What recovery (quantifiable measure) can be expected?
In recent years, the addition of an agglomeration drum has improved on the heap leaching process by allowing for a more efficient leach. The rotary drum agglomerator works by taking the crushed ore fines and agglomerating them into more uniform particles. This makes it much easier for the leaching solution to percolate through the pile, making its way through the channels between particles.
The addition of an agglomeration drum also has the added benefit of being able to pre-mix the leaching solution with the ore fines to achieve a more concentrated, homogeneous mixture and allow the leach to begin prior to the heap.
Although heap leach design has made significant progress over the last few years through the use of new materials and improved analytical tools, industrial experience shows that there are significant benefits from extending the design process beyond the liner and into the rock pile itself. Characterization of the physical and hydraulic (hydrodynamic) properties of ore-for-leach focuses on the direct measurement of the key properties of the ore, namely:
* The relationship between heap height and ore bulk density (density profile)
* The relationship between bulk density and percolation capacity (conductivity profile)
* The relationship between the bulk density, porosity and its components (micro and macro)
* The relationship between the moisture content and percolation capacity (conductivity curve)
* The relationship between the aforementioned parameters and the ore preparation practices (mining, crushing, agglomeration, curing, and method of placement)
Theoretical and numerical analysis, and operational data show that these fundamental mechanisms are controlled by scale, dimensionality, and heterogeneity, all of which adversely affect the scalability of metallurgical and hydrodynamic properties from the lab to the field. The dismissal of these mechanisms can result in a number of practical and financial problems that will resonate throughout the life of the heap impacting the financial return of the operation. Through procedures that go beyond the commonly employed metallurgical testing and the integration of data gleaned through real time 3D monitoring, a more complete representative characterization of the physicochemical properties of the heap environment is obtained. This improved understanding results in a significantly higher degree of accuracy in terms of creating a truly representative sample of the environment within the heap.
By adhering to the characterization identified above, a more comprehensive view of heap leach environments can be realized, allowing the industry to move away from the de facto black-box approach to a physicochemically inclusive industrial reactor model. | 0 | Metallurgy |
Partial agonists are defined as drugs that, at a given receptor, might differ in the amplitude of the functional response that they elicit after maximal receptor occupancy. Although they are agonists, partial agonists can act as a competitive antagonist in the presence of a full agonist, as it competes with the full agonist for receptor occupancy, thereby producing a net decrease in the receptor activation as compared to that observed with the full agonist alone. Clinically, their usefulness is derived from their ability to enhance deficient systems while simultaneously blocking excessive activity. Exposing a receptor to a high level of a partial agonist will ensure that it has a constant, weak level of activity, whether its normal agonist is present at high or low levels. In addition, it has been suggested that partial agonism prevents the adaptive regulatory mechanisms that frequently develop after repeated exposure to potent full agonists or antagonists. E.g. Buprenorphine, a partial agonist of the μ-opioid receptor, binds with weak morphine-like activity and is used clinically as an analgesic in pain management and as an alternative to methadone in the treatment of opioid dependence. | 1 | Gene expression + Signal Transduction |
Many hormones and their structural and functional analogs are used as medication. The most commonly prescribed hormones are estrogens and progestogens (as methods of hormonal contraception and as HRT), thyroxine (as levothyroxine, for hypothyroidism) and steroids (for autoimmune diseases and several respiratory disorders). Insulin is used by many diabetics. Local preparations for use in otolaryngology often contain pharmacologic equivalents of adrenaline, while steroid and vitamin D creams are used extensively in dermatological practice.
A "pharmacologic dose" or "supraphysiological dose" of a hormone is a medical usage referring to an amount of a hormone far greater than naturally occurs in a healthy body. The effects of pharmacologic doses of hormones may be different from responses to naturally occurring amounts and may be therapeutically useful, though not without potentially adverse side effects. An example is the ability of pharmacologic doses of glucocorticoids to suppress inflammation. | 1 | Gene expression + Signal Transduction |
The closed loop recirculation is a proven method of directly monitoring hydrogen in molten aluminium. A small volume of carrier gas, usually nitrogen, is brought in contact with the melt by means of an immersed probe, and is continuously recirculated in the closed loop until its hydrogen content reaches equilibrium with the vapor pressure of H in the melt. The H concentration in the gas is measured and converted into a reading of the gas concentration in the metal. This method is fast, reproducible, and accurate, and can be used online on the factory floor.
The amount of H in the gas loop of the instrument is determined by a thermal conductivity sensor, which provides high reproducibility and a broad measurement range. | 0 | Metallurgy |
The dominant technology used for the production of transgenic plants for transient expression is Agrobacterium-mediated genetic transformation, or "agroinfiltration," and virus expression machinery. Agrobacterium tumefaciens and related Agrobacterium species are well-known plant pathogens that have been engineered to efficiently transfer specific pieces of DNA (called transfer DNA, or T-DNA) into the plant nucleus using binary vector systems, which consists of a T-DNA binary vector and a vir helper plasmid. This binary vector separates T-DNA from trans-acting virulence proteins that help mediate the transfer. Advantages of this method include modularity of broad host-range plasmids of small size through standard molecular biology techniques. Furthermore, since the parent tumor-inducing plasmid in Agrobacterium strains have been disarmed and only non-reproductive cells have been modified (as opposed to germ-line modifications), the process is considered environmentally harmless.
Applications of this process has resulted in advancements made in the use of plants to synthetic biology. Plant-derived bioproducts show promise of high competitiveness towards traditional mammalian cell expression systems. | 1 | Gene expression + Signal Transduction |
RNA polymerase II holoenzyme is a form of eukaryotic RNA polymerase II that is recruited to the promoters of protein-coding genes in living cells. It consists of RNA polymerase II, a subset of general transcription factors, and regulatory proteins known as . | 1 | Gene expression + Signal Transduction |
All the structural genes of an operon are turned ON or OFF together, due to a single promoter and operator upstream to them, but sometimes more control over the gene expression is needed. To achieve this aspect, some bacterial genes are located near together, but there is a specific promoter for each of them; this is called gene clustering. Usually these genes encode proteins which will work together in the same pathway, such as a metabolic pathway. Gene clustering helps a prokaryotic cell to produce metabolic enzymes in a correct order.
In one study, it has been posited that in the Asgard (archaea), ribosomal protein coding genes occur in clusters that are less conserved in their organization than in other Archaea; the closer an Asgard (archaea) is to the eukaryotes, the more dispersed is the arrangement of the ribosomal protein coding genes. | 1 | Gene expression + Signal Transduction |
In addition to RNA, proteins can undergo splicing. Although the biomolecular mechanisms are different, the principle is the same: parts of the protein, called inteins instead of introns, are removed. The remaining parts, called exteins instead of exons, are fused together.
Protein splicing has been observed in a wide range of organisms, including bacteria, archaea, plants, yeast and humans. | 1 | Gene expression + Signal Transduction |
Prp24 (precursor RNA processing, gene 24) is a protein part of the pre-messenger RNA splicing process and aids the binding of U6 snRNA to U4 snRNA during the formation of spliceosomes. Found in eukaryotes from yeast to E. coli, fungi, and humans, Prp24 was initially discovered to be an important element of RNA splicing in 1989. Mutations in Prp24 were later discovered in 1991 to suppress mutations in U4 that resulted in cold-sensitive strains of yeast, indicating its involvement in the reformation of the U4/U6 duplex after the catalytic steps of splicing. | 1 | Gene expression + Signal Transduction |
Another regulatory element located upstream of the gene is an enhancer. Enhancers function as a "turn on" switch in gene expression and will activate the promoter region of a particular gene while silencers act as the "turn off" switch. Though these two regulatory elements work against each other, both sequence types affect the promoter region in very similar ways. Because silencers have not been thoroughly identified and analyzed, the extensive research on enhancers has aided biologists in understanding the mechanics of the silencer. Enhancers can be found in many of the same areas that silencers are found, such as upstream of the promoter by many kilobase pairs, or even downstream within the intron of the gene. DNA looping is also a model function used by enhancers in order to shorten the proximity of the promoter to the enhancer. Enhancers also function with transcription factors in order to initiate expression, much like silencers can with repressors. | 1 | Gene expression + Signal Transduction |
An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word intron is derived from the term agenic regi, i.e., a region inside a gene. The term intron refers to both the DNA sequence within a gene and the corresponding RNA sequence in RNA transcripts. The non-intron sequences that become joined by this RNA processing to form the mature RNA are called exons.
Introns are found in the genes of most eukaryotes and many eukaryotic viruses and they can be located in both protein-coding genes and genes that function as RNA (noncoding genes). There are four main types of introns: tRNA introns, group I introns, group II introns, and spliceosomal introns (see below). Introns are rare in Bacteria and Archaea (prokaryotes). | 1 | Gene expression + Signal Transduction |
In West Africa, copper was used as medium of exchange, symbols of status and kingship, jewelry, and ritual purposes; this was a part of Bantu tradition prior to their expansion into Central Africa. The use of copper in the Iron Age of Central Africa was produced because of indigenous or internal demand rather than those from outside, and it is thought to be a sensitive sign of political and social change.
Copper appeared to be a prestigious metal in Central and Southern Africa. In Central Africa copper has been found in places where copper is not produced, implying some sort of commerce. Also the majority of artifacts found suggest that the primary use for copper in the area was for decorative purposes. The available evidence shows that prior to fifteenth century Zimbabwean Iron Age site also placed higher value in copper than gold, though the date may have to be pushed with recent carbon dates.
It is thought that through trade with India and later Portugal Zimbabwe started to value gold as prestige metal, however it did not replace copper. Archaeological and documentary sources may skew the record in favor of nonperishable elements of culture and not give enough credit to pastoral and mixed farming activities that were needed to sustain these Iron Age populations. They do make it clear that copper was an important part of the exchange economies of Central and Southern Africa. The site of Bosutswe is evidence that copper and other precious metals were vital to trade in the area.
Tswana towns of the pre-colonial period in South Africa, such as the Tlokwa capital at Marothodi near the Pilanesberg National Park, demonstrate a continuation of native copper production into the early nineteenth century. In this period, archaeological research suggests that copper production had intensified significantly to meet growing regional demands. | 0 | Metallurgy |
The origin of the name Ariconium is uncertain, as is its pre-Roman name. The Romans often named a place in recognition of some feature of the terrain, or in recognition of the people then living in the area. There is a similarity to other Roman place-names such as Viroconium (post-Roman Welsh: Caer Guricon), also known as Uriconium, but as yet no established connection to them.
It is generally believed that Ariconium is the origin of the name of the post-Roman kingdom of Ergyng, although Ariconium was located outside the later boundaries of Ergyng. It is plausible that both derive from an earlier name for a wider area. In turn, Ergyng is believed to have given its name to Archenfield.
Since 2008, it has been used as the name of a united benefice of six Church of England parishes in the area - Aston Ingham, Hope Mansell, Lea, Linton, Upton Bishop and Weston under Penyard. | 0 | Metallurgy |
Protein arginine N-methyltransferase-4 (PRMT4/CARM1) methylation of arginine residues within proteins plays a critical key role in transcriptional regulation (see the PRMT4 pathway on the left). PRMT4 binds to the classes of transcriptional activators known as p160 and CBP/p300. The modified forms of these proteins are involved in stimulation of gene expression via steroid hormone receptors. Significantly, PRMT4 methylates core histones H3 and H4, which are also targets of the histone acetylase activity of CBP/p300 coactivators. PRMT4 recruitment of chromatin by binding to coactivators increases histone methylation and enhances the accessibility of promoter regions for transcription. Methylation of the transcriptional coactivator CBP by PRMT4 inhibits binding to CREB and thereby partitions the limited cellular pool of CBP for steroid hormone receptor interaction. | 1 | Gene expression + Signal Transduction |
mTOR is implicated in the failure of a pruning mechanism of the excitatory synapses in autism spectrum disorders. | 1 | Gene expression + Signal Transduction |
Corinthian bronze, also named Corinthian brass or aes Corinthiacum, was a highly valuable metal alloy in classical antiquity. It is thought to be an alloy of copper with gold or silver (or both), although it has also been contended that it was simply a very high grade of bronze, or a kind of bronze that was manufactured in Corinth. It is referred to in various ancient texts, but no certain examples of Corinthian bronze exist today. However, it has been increasingly suggested that a number of artefacts previously described as niello in fact use a technique of patinated metal that may be the same as Corinthian bronze and is similar to the Japanese Shakudō.
Its composition was long a mystery, but contemporary thinking is that Corinthian bronze was "a patinated alloy of copper with some gold and silver", perhaps the same as the hesmen kem or "black copper" of Ancient Egyptian art. This is shown by ancient texts to be a prestigious material, and apparently survives in a number of statuettes of "distinctive black-patinated, inlaid metal", of which scientific analysis shows "that some have a highly unusual composition containing small amounts of gold, silver and arsenic in the alloy", and are broadly similar to Shakudō. | 0 | Metallurgy |
Integration was the watchword as the various processes were brought together by large corporations, from mining the iron ore to shipping the finished product to wholesalers. The typical steelworks was a giant operation, including blast furnaces, Bessemer converters, open-hearth furnaces, rolling mills, coke ovens and foundries, as well as supported transportation facilities. The largest ones were operated in the region from Chicago to St. Louis to Baltimore, Philadelphia and Buffalo. Smaller operations appeared in Birmingham, Alabama, and in California.
The industry grew slowly but other industries grew even faster, so that by 1967, as the downward spiral began, steel accounted for 4.4% of manufacturing employment and 4.9% of manufacturing output. After 1970 American steel producers could no longer compete effectively with low-wage producers elsewhere. Imports and local mini-mills undercut sales.
Per-capita steel consumption in the U.S. peaked in 1977, then fell by half before staging a modest recovery to levels well below the peak.
Most mills were closed. Bethlehem went bankrupt in 2001. In 1984, Republic merged with Jones and Laughlin Steel Company; the new firm went bankrupt in 2001. US Steel diversified into oil (Marathon Oil was spun off in 2001). Finally US Steel reemerged in 2002 with plants in three American locations (plus one in Europe) that employed fewer than one-tenth the 168,000 workers of 1902. By 2001 steel accounted for only 0.8% of manufacturing employment and 0.8% of manufacturing output.
The world steel industry peaked in 2007. That year, ThyssenKrupp spent $12 billion to build the two most modern mills in the world, in Alabama and Brazil. The worldwide great recession starting in 2008, however, with its heavy cutbacks in construction, sharply lowered demand and prices fell 40%. ThyssenKrupp lost $11 billion on its two new plants, which sold steel below the cost of production. Finally in 2013, ThyssenKrupp offered the plants for sale at under $4 billion. | 0 | Metallurgy |
The first recorded attempt to make copper clad steel wire took place in the early 1860s. Although for over 100 years people had been suggesting various ways of uniting copper and steel, it was not until the period mentioned that Farmer and Milliken tried wrapping a strip of copper about a steel wire. American engineers in 1883 and again in the 1890s made attempts to produce a copper-steel wire, in one instance at least, by electroplating copper on steel.
The Duplex Metals Co. traces its beginning to John Ferreol Monnot between 1900 and 1905. He had been very interested in the work of Mr. Martin in Paris.
:"After several years devoted to experimenting, [he] organized the Duplex Metals Company. Prior to his discovery of the process under which this company operates in producing its copper clad, probably almost every other possible way of welding copper and steel together had been tried by Mr. Monnot, but found useless for the purpose." | 0 | Metallurgy |
Historically, this approach was seen through the New England colonies. Virtually every old home is a clapboard structure fitted with shutters applied in this manner. They were likely hung on the casing to allow for the frost heaves and movement of the structures in the harsh New England winters. The shutters simply allowed the house to heave and settle behind them.
A strap hinge with a zero offset and an angle pintle matched to the thickness of the shutter will serve in every case. The shutter is removed from the face of the casing by the thickness of the shutter plus the diameter of the pintle pin leaving the shutter to clear the corner of the casing. | 0 | Metallurgy |
Regulatory sequences for the insulin gene are:
* A5
* Z
* negative regulatory element (NRE)
* C2
* E2
* A3
* cAMP response element
* A2
* CAAT enhancer binding (CEB)
* C1
* E1
* G1 | 1 | Gene expression + Signal Transduction |
When a concrete structure is heavily reinforced, the very dense rebar network can block the contraction movement of the protecting concrete cover located above the external layer of reinforcement bars due to the natural drying shrinkage process. As a consequence, a network of fissures with the characteristic honeycomb pattern also typical for the cracks resulting from the expansive chemical reactions (ASR, DEF, ESA) forms.
The formation of fissures in the concrete cover above the reinforcement bars represents a preferential pathway for the ingress of water and aggressive agents such as carbon dioxide| (lowering of pH around the rebar) and chloride anions (pitting corrosion) into concrete. The physical formation of cracks therefore favors the chemical degradation of concrete and aggravates steel corrosion. Physical and chemical degradation processes are intimately coupled, and the presence of water infiltrations also accelerates the formation of expansive products of harmful swelling chemical reactions (iron corrosion products, ASR, DEF, ISA, ESA).
Different approaches and methods have been developed to attempt to quantitatively estimate the influence of cracks in concrete structures on carbonation and chloride penetration. Their aim is to avoid underestimating the penetration depth of these harmful chemical agents and to calculate a sufficient thickness for the concrete cover to protect the rebar against corrosion during the whole service life of the concrete structure. | 0 | Metallurgy |
A ρ factor (Rho factor) is a bacterial protein involved in the termination of transcription. Rho factor binds to the transcription terminator pause site, an exposed region of single stranded RNA (a stretch of 72 nucleotides) after the open reading frame at C-rich/G-poor sequences that lack obvious secondary structure.
Rho factor is an essential transcription protein in bacteria. In Escherichia coli, it is a ~274.6 kD hexamer of identical subunits. Each subunit has an RNA-binding domain and an ATP-hydrolysis domain. Rho is a member of the RecA/SF5 family of ATP-dependent hexameric helicases that function by wrapping nucleic acids around a single cleft extending around the entire hexamer. Rho functions as an ancillary factor for RNA polymerase.
There are two types of transcriptional termination in bacteria, rho-dependent termination and intrinsic termination (also called Rho-independent termination). Rho-dependent terminators account for about half of the E. coli factor-dependent terminators. Other termination factors discovered in E. coli include Tau and nusA. Rho-dependent terminators were first discovered in bacteriophage genomes. | 1 | Gene expression + Signal Transduction |
Flocculation is widely employed to measure the progress of curd formation in the initial stages of cheese making to determine how long the curds must set. The reaction involving the rennet micelles are modeled by Smoluchowski kinetics. During the renneting of milk the micelles can approach one another and flocculate, a process that involves hydrolysis of molecules and macropeptides.
Flocculation is also used during cheese wastewater treatment. Three different coagulants are mainly used:
* FeSO (iron(II) sulfate)
* Al(SO) (aluminium sulfate)
* FeCl (iron(III) chloride) | 0 | Metallurgy |
Humans have between 10 and 20 million olfactory receptor neurons (ORNs). In vertebrates, ORNs are bipolar neurons with dendrites facing the external surface of the cribriform plate with axons that pass through the cribriform foramina with terminal end at olfactory bulbs. The ORNs are located in the olfactory epithelium in the nasal cavity. The cell bodies of the ORNs are distributed among all three of the stratified layers of the olfactory epithelium.
Many tiny hair-like non-motile cilia protrude from the olfactory receptor cell's dendrites. The dendrites extend to the olfactory epithelial surface and each ends in a dendritic knob from which around 20 to 35 cilia protrude. The cilia have a length of up to 100 micrometres and with the cilia from other dendrites form a meshwork in the olfactory mucus. The surface of the cilia is covered with olfactory receptors, a type of G protein-coupled receptor. Each olfactory receptor cell expresses only one type of olfactory receptor (OR), but many separate olfactory receptor cells express ORs which bind the same set of odors. The axons of olfactory receptor cells which express the same OR converge to form glomeruli in the olfactory bulb. | 1 | Gene expression + Signal Transduction |
The synthesis and degradation of (p)ppGpp have been most extensively characterized in the bacterial model organism Escherichia coli. | 1 | Gene expression + Signal Transduction |
The Ames process is a process by which pure uranium metal is obtained. It can be achieved by mixing any of the uranium halides (commonly uranium tetrafluoride) with magnesium metal powder or aluminium metal powder. | 0 | Metallurgy |
Whiskers can cause short circuits and arcing in electrical equipment. The phenomenon was discovered by telephone companies in the late 1940s and it was later found that the addition of lead to tin solder provided mitigation. The European Restriction of Hazardous Substances Directive (RoHS), which took effect on July 1, 2006, restricted the use of lead in various types of electronic and electrical equipment. This has driven the use of lead-free alloys with a focus on preventing whisker formation . Others have focused on the development of oxygen-barrier coatings to prevent whisker formation.
Airborne zinc whiskers have been responsible for increased system failure rates in computer server rooms. Zinc whiskers grow from galvanized (electroplated) metal surfaces at a rate of up to a millimeter per year with a diameter of a few micrometers. Whiskers can form on the underside of zinc electroplated floor tiles on raised floors. These whiskers can then become airborne within the floor plenum when the tiles are disturbed, usually during maintenance. Whiskers can be small enough to pass through air filters and can settle inside equipment, resulting in short circuits and system failure.
Tin whiskers do not have to be airborne to damage equipment, as they are typically already growing directly in the environment where they can produce short circuits, i.e., the electronic equipment itself. At frequencies above 6 GHz or in fast digital circuits, tin whiskers can act like miniature antennas, affecting the circuit impedance and causing reflections. In computer disk drives they can break off and cause head crashes or bearing failures. Tin whiskers often cause failures in relays and have been found upon examination of failed relays in nuclear power facilities. Pacemakers have been recalled due to tin whiskers. Research has also identified a particular failure mode for tin whiskers in vacuum (such as in space), where in high-power components a short-circuiting tin whisker is ionized into a plasma that is capable of conducting hundreds of amperes of current, massively increasing the damaging effect of the short circuit. The possible increase in the use of pure tin in electronics due to the RoHS directive drove JEDEC and IPC to release a tin whisker acceptance testing standard and mitigation practices guideline intended to help manufacturers reduce the risk of tin whiskers in lead-free products.
Silver whiskers often appear in conjunction with a layer of silver sulfide, which forms on the surface of silver electrical contacts operating in an atmosphere rich in hydrogen sulfide and high humidity. Such atmospheres can exist in sewage treatment plants and paper mills.
Whiskers over 20 µm in length were observed on gold-plated surfaces and noted in a 2003 NASA internal memorandum.
The effects of metal whiskering were chronicled on History Channels program Engineering Disasters' 19. | 0 | Metallurgy |
Binding of targeting sequence elements by CTCF can block the interaction between enhancers and promoters, therefore limiting the activity of enhancers to certain functional domains. Besides acting as enhancer blocking, CTCF can also act as a chromatin barrier by preventing the spread of heterochromatin structures. | 1 | Gene expression + Signal Transduction |
GenePattern is available:
# As a free public web application, hosted on Amazon Web Services. Users can create accounts, perform analyses, and create pipelines on the server.
# As open-source software that can be downloaded and installed locally.
# Public web servers hosted by other organizations. | 1 | Gene expression + Signal Transduction |
Cyclic Corrosion Testing (CCT) has evolved in recent years, largely within the automotive industry, as a way of accelerating real-world corrosion failures, under laboratory controlled conditions.
As the name implies, the test comprises different climates which are cycled automatically so the samples under test undergo the same sort of changing environment that would be encountered in the natural world. The intention being to bring about the type of failure that might occur naturally, but more quickly i.e. accelerated. By doing this manufacturers and suppliers can predict, more accurately, the service life expectancy of their products.
Until the development of Cyclic Corrosion Testing, the traditional Salt spray test was virtually all that manufacturers could use for this purpose. However, this test was never intended for this purpose. Because the test conditions specified for salt spray testing are not typical of a naturally occurring environment, this type of test cannot be used as a reliable means of predicting the ‘real world’ service life expectancy for the samples under test. The sole purpose of the salt spray test is to compare and contrast results with previous experience to perform a quality audit. So, for example, a spray test can be used to ‘police’ a production process and forewarn of potential manufacturing problems or defects, which might affect corrosion resistance.
To recreate these different environments within an environmental chamber requires much more flexible testing procedures than are available in a standard salt spray chamber.
The lack of correlation between results obtained from traditional salt spray testing and the ‘real world’ atmospheric corrosion of vehicles, left the automotive industry without a reliable test method for predicting the service life expectancy of their products. This was and remains of particular concern in an industry where anti-corrosion warranties have been gradually increasing and now run to several years for new vehicles.
With ever increasing consumer pressure for improved vehicle corrosion resistance and a few ‘high profile’ corrosion failures amongst some vehicle manufactures – with disastrous commercial consequences, the automotive industry recognized the need for a different type of corrosion test.
Such a test would need to simulate the types of conditions a vehicle might encounter naturally, but recreate and accelerate these conditions, with good repeatability, within the convenience of the laboratory.
CCT is effective for evaluating a variety of corrosion types, including galvanic corrosion and crevice corrosion. One of the earliest introduced cyclic testing machines was the Prohesion cabinet. | 0 | Metallurgy |
This piece is the smaller part of the fragment broken during Bahadur Shah's reign. Henry Cousens (1902–03) measured its length as . The part with the square cross-section measured , while the part with the octagonal section measured . Klaus Roessler (1995) found this piece to be long. Roessler estimated its weight at .
The piece was removed from the Lat Masjid site at an unknown time. In February 1903, Henry Cousens of ASI found it in Anand High School, where a museum had been set up in 1902. The museum was relocated to another site between the years 1922 and 1942. When this happened, the pillar was brought back to the Lat Masjid and placed horizontally on the ground. | 0 | Metallurgy |
Brinelling is a material surface failure caused by Hertz contact stress that exceeds the material limit. It usually occurs in situations where a significant load force is distributed over a relatively small surface area. Brinelling typically results from a heavy or repeated impact load, either while stopped or during rotation, though it can also be caused by just one application of a force greater than the material limit.
Brinelling can be caused by a heavy load resting on a stationary bearing for an extended length of time. The result is a permanent dent or "brinell mark". The brinell marks will often appear in evenly spaced patterns along the bearing races, resembling the primary elements of the bearing, such as rows of indented lines for needle or roller bearings or rounded indentations in ball bearings. It is a common cause of roller bearing failures, and loss of preload in bolted joints when a hardened washer is not used. For example, brinelling occurs in casters when the ball bearings within the swivel head produce grooves in the hard cap, thus degrading performance by increasing the required swivel force. | 0 | Metallurgy |
Alloying a metal is done by combining it with one or more other elements. The most common and oldest alloying process is performed by heating the base metal beyond its melting point and then dissolving the solutes into the molten liquid, which may be possible even if the melting point of the solute is far greater than that of the base. For example, in its liquid state, titanium is a very strong solvent capable of dissolving most metals and elements. In addition, it readily absorbs gases like oxygen and burns in the presence of nitrogen. This increases the chance of contamination from any contacting surface, and so must be melted in vacuum induction-heating and special, water-cooled, copper crucibles. However, some metals and solutes, such as iron and carbon, have very high melting-points and were impossible for ancient people to melt. Thus, alloying (in particular, interstitial alloying) may also be performed with one or more constituents in a gaseous state, such as found in a blast furnace to make pig iron (liquid-gas), nitriding, carbonitriding or other forms of case hardening (solid-gas), or the cementation process used to make blister steel (solid-gas). It may also be done with one, more, or all of the constituents in the solid state, such as found in ancient methods of pattern welding (solid-solid), shear steel (solid-solid), or crucible steel production (solid-liquid), mixing the elements via solid-state diffusion.
By adding another element to a metal, differences in the size of the atoms create internal stresses in the lattice of the metallic crystals; stresses that often enhance its properties. For example, the combination of carbon with iron produces steel, which is stronger than iron, its primary element. The electrical and thermal conductivity of alloys is usually lower than that of the pure metals. The physical properties, such as density, reactivity, Young's modulus of an alloy may not differ greatly from those of its base element, but engineering properties such as tensile strength, ductility, and shear strength may be substantially different from those of the constituent materials. This is sometimes a result of the sizes of the atoms in the alloy, because larger atoms exert a compressive force on neighboring atoms, and smaller atoms exert a tensile force on their neighbors, helping the alloy resist deformation. Sometimes alloys may exhibit marked differences in behavior even when small amounts of one element are present. For example, impurities in semiconducting ferromagnetic alloys lead to different properties, as first predicted by White, Hogan, Suhl, Tian Abrie and Nakamura.
Unlike pure metals, most alloys do not have a single melting point, but a melting range during which the material is a mixture of solid and liquid phases (a slush). The temperature at which melting begins is called the solidus, and the temperature when melting is just complete is called the liquidus. For many alloys there is a particular alloy proportion (in some cases more than one), called either a eutectic mixture or a peritectic composition, which gives the alloy a unique and low melting point, and no liquid/solid slush transition. | 0 | Metallurgy |
When the RNA transcript reaches 7 nucleotides long, transcription enters the elongation phase, the beginning of which is characterised by the collapsing of the DNA bubble and the ejection of TFIIB. This is thought to be because the nascent RNA clashes with the B linker helix when it is 6 bases long and upon further elongation to 12-13 bases it will clash with the B-reader and B-ribbon leading to dissociation. The DNA duplex also clashes with the B linker above the rudder (caused by rewinding of the DNA into a double helix). | 1 | Gene expression + Signal Transduction |
An MTC provides traceability and assurance to the end user about the quality of the steel used and the process used to produce it.
Typically a European MTC will be produced to EN 10204. High quality steels for pressure vessel of structural purposes will be declared to 2.1 or 2.2 or certificated to 3.1 or 3.2. (EDIT: type is declared not by chapter in the document, but by type name, so edited the numbering)
The MTC will specify the type of certificate, the grade of steel and any addenda. It will also specify the results of chemical and physical examination to allow the purchaser or end user to compare the plate to the requirements of the relevant standards. | 0 | Metallurgy |
NbGe was discovered to be a superconductor in 1973 and for 13 years (until the discovery in 1986 of the cuprate superconductors) it held the record as having the highest critical temperature.
It has not been as widely used for superconductive applications as niobium–tin or niobium–titanium. | 0 | Metallurgy |
Symptoms of M2DS include infantile hypotonia and failure to thrive, delayed psychomotor development, impaired speech, abnormal or absent gait, epilepsy, spasticity, gastrointestinal motility problems, recurrent infections, and genitourinary abnormalities. Many of those affected by M2DS also fit diagnostic criteria for autism. M2DS can be associated with syndromic facies, namely an abnormally flat back of the head, underdevelopment of the midface, ear anomalies, deep-set eyes, prominent chin, pointed nose, and a flat nasal bridge. | 1 | Gene expression + Signal Transduction |
Subsets and Splits