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Survivin is a member of the IAP family of antiapoptotic proteins. It is shown to be conserved in function across evolution as homologues of the protein are found both in vertebrates and invertebrates. The first members of the IAPs identified were from the baculovirus IAPs, Cp-IAP and Op-IAP, which bind to and inhibit caspases as a mechanism that contributes to its efficient infection and replication cycle in the host. Later, five more human IAPs that included XIAP, c-IAPl, C-IAP2, NAIP, and survivin were discovered. Survivin, like the others, was discovered by its structural homology to IAP family of proteins in human B-cell lymphoma. The human IAPs, XIAP, c-IAPl, C-IAP2 have been shown to bind to caspase-3 and -7, which are the effector caspases in the signaling pathway of apoptosis. It is not known with absolute certainty though, how the IAPs inhibit apoptosis mechanistically at the molecular level.
A common feature that is present in all IAPs in the presence of a BIR (Baculovirus IAP Repeat, a ~70 amino acid motif) in one to three copies. It was shown by Tamm et al. that knocking out BIR2 from XIAP was enough to cause a loss of function in terms of XIAPs ability to inhibit caspases. This gives the implication that it is within these BIR motifs that contains the anti-apoptotic function of these IAPs. Survivins one BIR domain shows a similar sequence compared to that of XIAPs BIR domains. | 1 | Gene expression + Signal Transduction |
LaNi has a calcium pentacopper (CaCu) type crystal structure, with a hexagonal lattice, space group is P6/mmm (No. 191), with lanthanum atom is located at coordinate origin 1a (0,0,0), two nickel atoms are located at 2c (1/ 3,2/3,0) and (2/3,1/3,0), the other three at 3g (1/2,0,1/2), (0,1/2,1/2), (1/2,1/2,1/2), with a=511pm, c=397pm. The unit cell contains 1 LaNi atom, the volume is 90×10 cm, the LaNi unit cell contains a larger The six deformed tetrahedral voids can be used to fill in hydrogen atoms. | 0 | Metallurgy |
The haloacid dehalogenase (HAD) superfamily is a further PP group that uses Asp as a nucleophile and was recently shown to have dual-specificity. These PPs can target both Ser and Tyr, but are thought to have greater specificity towards Tyr. A subfamily of HADs, the Eyes Absent Family (Eya), are also transcription factors and can therefore regulate their own phosphorylation and that of transcriptional cofactor/s, and contribute to the control of gene transcription. The combination of these two functions in Eya reveals a greater complexity of transcriptional gene control than previously thought . A further member of this class is the RNA polymerase II C-terminal domain phosphatase. While this family remains poorly understood, it is known to play important roles in development and nuclear morphology. | 1 | Gene expression + Signal Transduction |
Fluxes have several serious drawbacks:
* Corrosivity, which is mostly due to the aggressive compounds of the activators; hygroscopic properties of the flux residues may aggravate the effects
* Interference with test equipment, which is due to the insulating residues deposited on the test contacts on electronic circuit boards
* Interference with machine vision systems when the layer of flux or its remains is too thick or improperly located
* Contamination of sensitive parts, e.g. facets of laser diodes, contacts of connectors and mechanical switches, and MEMS assemblies
* Deterioration of electrical properties of printed circuit boards, as soldering temperatures are above the glass transition temperature of the board material and flux components (e.g. glycols, or chloride and bromide ions) can diffuse into its matrix; e.g. water-soluble fluxes containing polyethylene glycol were demonstrated to have such impact
* Deterioration of high-frequency circuit performance by flux residues
* Deterioration of surface insulation resistance, which tends to be as much as three orders of magnitude lower than the bulk resistance of the material
* Electromigration and growth of whiskers between nearby traces, aided by ionic residues, surface moisture and a bias voltage
* The fumes liberated during soldering have adverse health effects, and volatile organic compounds can be outgassed during processing
* The solvents required for post-soldering cleaning of the boards are expensive and may have adverse environmental impact
In special cases the drawbacks are sufficiently serious to warrant using fluxless techniques. | 0 | Metallurgy |
* Highly parallel identification of active, tissue-specific transcriptional enhancers in whole embryos
* Candidate enhancers activity assayed in a genomic context
* High specificity of detected enhancers | 1 | Gene expression + Signal Transduction |
*BAT1 aka DDX39B
*HNRPD Homo sapiens heterogeneous nuclear ribonucleoprotein D (AU-rich element RNA
*HNRPK Homo sapiens heterogeneous nuclear ribonucleoprotein K (HNRPK), transcript
*PABPN1 poly(A) binding protein, nuclear 1
*SRSF3 splicing factor, arginine/serine-rich | 1 | Gene expression + Signal Transduction |
Abé (1996) explores the record of iron and steel firms in Victorian England by analyzing Bolckow Vaughan & Company. It was wedded for too long to obsolescent technology and was a very late adopter of the open hearth furnace method. Abé concludes that the firm—and the British steel industry—suffered from a failure of entrepreneurship and planning.
Blair (1997) explores the history of the British Steel industry since the Second World War to evaluate the impact of government intervention in a market economy. Entrepreneurship was lacking in the 1940s; the government could not persuade the industry to upgrade its plants. For generations the industry had followed a patchwork growth pattern which proved inefficient in the face of world competition. In 1946 the first steel development plan was put into practice with the aim of increasing capacity; the Iron and Steel Act 1949 meant nationalization of the industry in the form of the Iron and Steel Corporation of Great Britain. However, the reforms were dismantled by the Conservative Party governments in the 1950s. In 1967, under Labour Party control again, the industry was again nationalized. But by then twenty years of political manipulation had left companies such as the British Steel Corporation with serious problems: a complacency with existing equipment, plants operating under capacity (low efficiency), poor quality assets, outdated technology, government price controls, higher coal and oil costs, lack of funds for capital improvement, and increasing world market competition. By the 1970s the Labour government had its main goal to keep employment high in the declining industry. Since British Steel was a main employer in depressed regions, it had kept many mills and facilities that were operating at a loss. In the 1980s, Conservative Prime Minister Margaret Thatcher re-privatized BSC as British Steel plc. | 0 | Metallurgy |
The primary structure of the SUI1 protein is made up of 108 amino acids. The protein domain has a structure made of a seven-bladed beta-propeller and it also contains a C-terminal alpha helix. Homologues of SUI1 have been found in mammals, insects and plants. SUI1 is also evolutionary related to proteins from Escherichia coli (yciH), Haemophilus influenzae (HI1225) and Methanococcus vannielii. | 1 | Gene expression + Signal Transduction |
Solvent extraction – electrowinning (often referred to as "SX–EW") is a process frequently applied for recovering copper from low-grade and/or oxidised copper ore. It involves leaching the copper from the ore using an acidic solution, collecting the leach liquor containing the copper and contacting this solution with an organic extractant. The copper ions in the leach liquor transfer to the organic extractant, moving from a relatively low concentration to a higher concentration. The extractant is subsequently brought into contact with a second aqueous solution that is more acid than the original leach liquor, and the copper again moves, this time from the extractant into the aqueous solution. The result is an acidic solution of copper in which the copper concentration is high enough for it to be recovered by electrowinning. The solution destined for electrowinning is known as the electrolyte.
The electrolyte solution usually contains traces of the organic extractant that exist as tiny droplets within it. These need to be removed before the copper can be recovered in the electrowinning process, as the presence of minimal amounts of the extractant can cause difficulties by stripping and damaging the cathodes with a subsequent loss of cathode copper quality.
In the late 1980s, MIM built an SX–EW plant at Mount Isa to recover copper leached from low grade ore stockpiled while mining its Black Rock open cut in the 1960s. In a world first, a Jameson Cell was used to clean the electrolyte solution by removing the remaining organic solvent. This replaced the sand filters traditionally used.
The cell was 3 m high, twice the height of the early Cells used in MIM's lead–zinc concentrators, as it was thought that additional residence time would enhance recovery. It used a single downcomer. The downcomer was used to contact the electrolyte with air and the droplets of the organic extractant attached themselves to the air bubbles created in the downcomer.
After some initial modifications to the orifice size, the Cell was able to remove 70–90% of the entrained organic extractant. | 0 | Metallurgy |
In biology, the SECIS element (SECIS: selenocysteine insertion sequence) is an RNA element around 60 nucleotides in length that adopts a stem-loop structure. This structural motif (pattern of nucleotides) directs the cell to translate UGA codons as selenocysteines (UGA is normally a stop codon). SECIS elements are thus a fundamental aspect of messenger RNAs encoding selenoproteins, proteins that include one or more selenocysteine residues.
In bacteria the SECIS element appears soon after the UGA codon it affects. In archaea and eukaryotes, it occurs in the 3 UTR of an mRNA, and can cause multiple UGA codons within the mRNA to code for selenocysteine. One archaeal SECIS element, in Methanococcus, is located in the 5 UTR.
The SECIS element appears defined by sequence characteristics, i.e. particular nucleotides tend to be at particular positions in it, and a characteristic secondary structure. The secondary structure is the result of base-pairing of complementary RNA nucleotides, and causes a hairpin-like structure. The eukaryotic SECIS element includes non-canonical A-G base pairs, which are uncommon in nature, but are critically important for correct SECIS element function. Although the eukaryotic, archaeal and bacterial SECIS elements each share a general hairpin structure, they are not alignable, e.g. an alignment-based scheme to recognize eukaryotic SECIS elements will not be able to recognize archaeal SECIS elements. However, in Lokiarcheota, SECIS elements are more similar to eukaryotic elements.
In bioinformatics, several computer programs have been created that search for SECIS elements within a genome sequence, based on the sequence and secondary structure characteristics of SECIS elements. These programs have been used in searches for novel selenoproteins. | 1 | Gene expression + Signal Transduction |
Acid flux types (not used in electronics) may contain hydrochloric acid, zinc chloride or ammonium chloride, which are harmful to humans. Therefore, flux should be handled with gloves and goggles, and used with adequate ventilation.
Prolonged exposure to rosin fumes released during soldering can cause occupational asthma (formerly called colophony disease in this context) in sensitive individuals, although it is not known which component of the fumes causes the problem.
While molten solder has low tendency to adhere to organic materials, molten fluxes, especially of the resin/rosin type, adhere well to fingers. A mass of hot sticky flux can transfer more heat to skin and cause more serious burns than a comparable particle of non-adhering molten metal, which can be quickly shaken off. In this regard, molten flux is similar to molten hot glue. | 0 | Metallurgy |
There were various iron-making ventures during the 19th Century, and steel was made but only on a very small scale.
The first commercial scale production of steel in Australia was by William Sandford Limited at the Eskbank Ironworks at Lithgow, New South Wales, in 1901. The plant became Australias first integrated iron and steel works in 1907. It was later expanded by Charles Hoskins. The first steel rails rolled in Australia were rolled there in 1911. Between 1928 and 1932, the operations at Lithgow were transferred, under the management of Cecil Hoskins, to a new plant at Port Kembla, still the site of most of Australias steel production today.
The Minister for Public Works, Arthur Hill Griffith, had consistently advocated for the greater industrialization of Newcastle, then, under William Holman, personally negotiated the establishment of a steelworks with G. D. Delprat of BHP. Griffith was also the architect of the Walsh Island establishment.
In 1915, BHP ventured into steel manufacturing with its Newcastle Steelworks, which was closed in 1999. The long products side of the steel business was spun off to form OneSteel in 2000. BHPs decision to move from mining ore to open a steelworks at Newcastle was precipitated by the technical limitations in recovering value from mining the lower-lying sulphide ores. The discovery of Iron Knob and Iron Monarch near the western shore of the Spencer Gulf in South Australia combined with the development by the BHP metallurgist, Archibald Drummond Carmichael, of a technique for separating zinc sulphides from the accompanying earth and rock led BHP to implement the startlingly simple and cheap process for liberating vast amounts of valuable metals out of sulphide ores, including huge heaps of tailings and slimes up to' high. | 0 | Metallurgy |
The advantages of the ISASMELT process include:
* High productivity with a small footprint: Glencore's copper smelter in Mount Isa treats over 1 million t/y of copper concentrate through a single furnace 3.75 m in diameter. The small footprint makes the process well suited to retrofitting to existing smelters where there are significant space constraints
* Simple operation: the ISASMELT furnace does not require extensive feed preparation as the feed can be discharged from a belt conveyor directly into the furnace
* high energy efficiency: installing an ISASMELT furnace in the Mount Isa copper smelter reduced energy consumption by over 80% (through better use of the inherent energy contained in the sulfide concentrate) compared with the roaster and reverberatory furnaces previously used there
* Flexibility in feed types: ISASMELT furnaces have been used to smelt copper, lead and nickel concentrates with a wide range of compositions, including high levels of magnetite, and secondary materials, such as copper scrap and lead-acid battery paste
* Flexibility in fuel types: ISASMELT furnaces can operate with a variety of fuels, including lump coal of varying ranks, coke (lump or fine), petroleum coke, oil (including recycled oil), natural gas, and liquid petroleum gas, depending on which is the most economic at the smelter's location
* High turn-down ratio: the feed rate to a single ISASMELT installation can easily be scaled up or down, depending on the availability of concentrate and the needs of the smelter
* Low feed carry over: ISASMELT furnaces typically lose about 1% of the feed as carry-over with the waste gas, meaning that there is less material that needs to be returned to the furnace for retreatment
* Effective containment of fugitive emissions: because the furnace has only two openings at the top, any fugitive emissions can easily be captured
* High elimination of deleterious minor elements: due to the flushing action of the gases injected into the ISASMELT furnace slags, copper ISASMELT furnaces have a high elimination of minor elements, such as bismuth and arsenic, that can have deleterious effects on the properties of the product copper
* High sulfur dioxide concentration in the waste gas: the use of oxygen enrichment gives the ISASMELT plants high sulfur dioxide concentrations in the waste gas stream, making acid plants cheaper to build and operate
* Relatively low operating cost: the energy efficiency of the process, the simple feed preparation, the relative lack of moving parts, low feed carry-over rates, low labour requirements and the ease of replacing lances and refractory linings when they are worn give the ISASMELT process relatively low operating costs
* Relatively low capital cost: the simplicity of the construction of the ISASMELT furnaces and the ability to treat concentrate without drying make it cheaper than other smelting processes. | 0 | Metallurgy |
Trans-acting factors can be categorized by their interactions with the regulated genes, cis-acting elements of the genes, or the gene products. | 1 | Gene expression + Signal Transduction |
The Prefil method is similar to PoDFA but, in addition to the metallographic analysis, Prefil provides also an immediate feedback on metal cleanliness from the metal flowrate through the filter. Because everything about the filtration is well controlled (pressure, metal temperature, ...), the only parameter affecting the filtration speed is the inclusion content. One can determine the cleanliness level from the filtration curve (weight of metal filtered as a function of time). | 0 | Metallurgy |
Synapses function as ensembles within particular brain networks to control the amount of neuronal activity, which is essential for memory, learning, and behavior. Consequently, synaptic disruptions might have negative effects. In fact, alterations in cell-intrinsic molecular systems or modifications to environmental biochemical processes can lead to synaptic dysfunction. The synapse is the primary unit of information transfer in the nervous system, and correct synaptic contact creation during development is essential for normal brain function. In addition, several mutations have been connected to neurodevelopmental disorders, and that compromised function at different synapse locations is a hallmark of neurodegenerative diseases.
Synaptic defects are causally associated with early appearing neurological diseases, including autism spectrum disorders (ASD), schizophrenia (SCZ), and bipolar disorder (BP). On the other hand, in late-onset degenerative pathologies, such as Alzheimers (AD), Parkinsons (PD), and Huntington's (HD) diseases, synaptopathy is thought to be the inevitable end-result of an ongoing pathophysiological cascade. These diseases are identified by a gradual loss in cognitive and behavioral function and a steady loss of brain tissue. Moreover, these deteriorations have been mostly linked to the gradual build-up of protein aggregates in neurons, the composition of which may vary based on the pathology; all have the same deleterious effects on neuronal integrity. Furthermore, the high number of mutations linked to synaptic structure and function, as well as dendritic spine alterations in post-mortem tissue, has led to the association between synaptic defects and neurodevelopmental disorders, such as ASD and SCZ, characterized by abnormal behavioral or cognitive phenotypes.
Nevertheless, due to limited access to human tissue at late stages and a lack of thorough assessment of the essential components of human diseases in the available experimental animal models, it has been difficult to fully grasp the origin and role of synaptic dysfunction in neurological disorders. | 1 | Gene expression + Signal Transduction |
Archaeological evidence shows that bloomeries appeared in China around 800 BC. Originally it was thought that the Chinese started casting iron right from the beginning, but this theory has since been debunked by the discovery of more than ten iron digging implements found in the tomb of Duke Jing of Qin (d. 537 BC), whose tomb is located in Fengxiang County, Shaanxi (a museum exists on the site today). There is however no evidence of the bloomery in China after the appearance of the blast furnace and cast iron. In China, blast furnaces produced cast iron, which was then either converted into finished implements in a cupola furnace, or turned into wrought iron in a fining hearth.
Although cast iron farm tools and weapons were widespread in China by the 5th century BC, employing workforces of over 200 men in iron smelters from the 3rd century onward, the earliest blast furnaces constructed were attributed to the Han dynasty in the 1st century AD. These early furnaces had clay walls and used phosphorus-containing minerals as a flux. Chinese blast furnaces ranged from around two to ten meters in height, depending on the region. The largest ones were found in modern Sichuan and Guangdong, while the 'dwarf" blast furnaces were found in Dabieshan. In construction, they are both around the same level of technological sophistication.
The effectiveness of the Chinese human and horse powered blast furnaces was enhanced during this period by the engineer Du Shi (c. AD 31), who applied the power of waterwheels to piston-bellows in forging cast iron. Early water-driven reciprocators for operating blast furnaces were built according to the structure of horse powered reciprocators that already existed. That is, the circular motion of the wheel, be it horse driven or water driven, was transferred by the combination of a belt drive, a crank-and-connecting-rod, other connecting rods, and various shafts, into the reciprocal motion necessary to operate a push bellow. Donald Wagner suggests that early blast furnace and cast iron production evolved from furnaces used to melt bronze. Certainly, though, iron was essential to military success by the time the State of Qin had unified China (221 BC). Usage of the blast and cupola furnace remained widespread during the Song and Tang dynasties. By the 11th century, the Song dynasty Chinese iron industry made a switch of resources from charcoal to coke in casting iron and steel, sparing thousands of acres of woodland from felling. This may have happened as early as the 4th century AD.
The primary advantage of the early blast furnace was in large scale production and making iron implements more readily available to peasants. Cast iron is more brittle than wrought iron or steel, which required additional fining and then cementation or co-fusion to produce, but for menial activities such as farming it sufficed. By using the blast furnace, it was possible to produce larger quantities of tools such as ploughshares more efficiently than the bloomery. In areas where quality was important, such as warfare, wrought iron and steel were preferred. Nearly all Han period weapons are made of wrought iron or steel, with the exception of axe-heads, of which many are made of cast iron.
Blast furnaces were also later used to produce gunpowder weapons such as cast iron bomb shells and cast iron cannons during the Song dynasty. | 0 | Metallurgy |
An insulator is a type of cis-regulatory element known as a long-range regulatory element. Found in multicellular eukaryotes and working over distances from the promoter element of the target gene, an insulator is typically 300 bp to 2000 bp in length. Insulators contain clustered binding sites for sequence specific DNA-binding proteins and mediate intra- and inter-chromosomal interactions.
Insulators function either as an enhancer-blocker or a barrier, or both. The mechanisms by which an insulator performs these two functions include loop formation and nucleosome modifications. There are many examples of insulators, including the CTCF insulator, the gypsy insulator, and the β-globin locus. The CTCF insulator is especially important in vertebrates, while the gypsy insulator is implicated in Drosophila. The β-globin locus was first studied in chicken and then in humans for its insulator activity, both of which utilize CTCF.
The genetic implications of insulators lie in their involvement in a mechanism of imprinting and their ability to regulate transcription. Mutations to insulators are linked to cancer as a result of cell cycle disregulation, tumourigenesis, and silencing of growth suppressors. | 1 | Gene expression + Signal Transduction |
The main properties of these conductors include:
* Good corrosion resistance of copper
* High tensile strength of steel
* Resistance against material fatigue | 0 | Metallurgy |
Although arsenical bronze occurs in the archaeological record across the globe, the earliest artifacts so far known, dating from the 5th millennium BC, have been found on the Iranian plateau. Arsenic is present in a number of copper-containing ores (see table at right, adapted from Lechtman & Klein, 1999), and therefore some contamination of the copper with arsenic would be unavoidable. However, it is still not entirely clear to what extent arsenic was deliberately added to copper and to what extent its use arose simply from its presence in copper ores that were then treated by smelting to produce the metal.
Reconstructing a possible sequence of events in prehistory involves considering the structure of copper ore deposits, which are mostly sulphides. The surface minerals would contain some native copper and oxidized minerals, but much of the copper and other minerals would have been washed further into the ore body, forming a secondary enrichment zone. This includes many minerals such as tennantite, with their arsenic, copper and iron. Thus, the surface deposits would have been used first; with some work, deeper sulphidic ores would have been uncovered and worked, and it would have been discovered that the material from this level had better properties.
Using these various ores, there are four possible methods that may have been used to produce arsenical bronze alloys. These are:
* The direct addition of arsenic-bearing metals or ores such as realgar to molten copper. This method, although possible, lacks evidence.
* The reduction of antimony-bearing copper arsenates or fahlore to produce an alloy high in arsenic and antimony. This is entirely practicable.
* The reduction of roasted copper sulfarsenides such as tennantite and enargite. This method would result in the production of toxic fumes of arsenous oxide and the loss of much of the arsenic present in the ores.
* The co-smelting of oxidic and sulphidic ores such as malachite and arsenopyrite together. This method has been demonstrated to work well, with little in the way of dangerous fumes given off during it, because of the reactions together among the different minerals.
Furthermore, greater sophistication of metal workers is suggested by Thornton et al. They suggest that iron arsenide was deliberately produced as part of the copper-smelting process, to be traded and used to make arsenical bronze elsewhere by addition to molten copper.
Artifacts made of arsenical bronze cover the complete spectrum of metal objects, from axes to ornaments. The method of manufacture involved heating the metal in crucibles, and casting it into moulds made of stone or clay. After solidifying, it would be polished or, in the case of axes and other tools, work-hardened by beating the working edge with a hammer, thinning out the metal and increasing its strength. Finished objects could also be engraved or decorated as appropriate. | 0 | Metallurgy |
The crystal structure of NMT reveals two identical subunits, each with its own myristoyl CoA binding site. Each subunit consists of a large saddle-shaped β-sheet surrounded by α-helices. The symmetry of the fold is pseudo twofold. Myristoyl CoA binds at the N-terminal portion, while the C-terminal end binds the protein. | 1 | Gene expression + Signal Transduction |
If the general water speed or the degree of local turbulence in an installation is high, the protective film that would normally be formed on a copper tube as a result of slight initial corrosion, may be torn off the surface locally, permitting further corrosion to take place at that point. If this process continues it can produce deep localised attack of the type known as erosion-corrosion or impingement damage. The actual attack on the metal is by the corrosive action of the water to which it is exposed while the erosive factor is the mechanical removal of the corrosion product from the surface.
Impingement attack produces highly characteristic water-swept pits, which are often horseshoe shaped, or it can produce broader areas of attack. The leading edge of the pit is frequently undercut by the swirling action of the water. Usually, the surface of the metal within the pits or areas of attack is smooth and carries no substantial corrosion product. Erosion-corrosion is known to occur in pumped-circulation hot water distribution systems, and even in cold water distribution systems, if the water velocities are too high. The factors influencing the attack include the chemical character of the water passing through the system, the temperature, the average water velocity in the system and the presence of any local features likely to induce turbulence in the water stream.
It is unusual for the general water velocity in a system to be so high that impingement attack occurs throughout the whole of the copper pipework. More commonly, the velocity is just sufficiently low for satisfactory protective films to be formed and to remain in position on most of the system, with impingement damage more likely to occur where there is an abrupt change in the direction of water flow giving rise to a high degree of turbulence, such as at tee pieces and elbow fittings. It is not generally realised how great an effect small obstructions can have on the flow pattern of water in a pipe-work system and the extent to which they can induce turbulence and cause corrosion-erosion. For example, it is most important, as far as possible, to ensure that copper tubes cut with a tube cutter are deburred before making the joint. Also a gap between the tube end and the stop in the fitting, due to the tube not having been cut to the correct length and fully inserted into the socket of the fitting, can also induce turbulence in the water stream. | 0 | Metallurgy |
A large group of bacterial exotoxins are referred to as "A/B toxins", in essence because they are formed from two subunits. The "A" subunit possesses enzyme activity, and is transferred to the host cell following a conformational change in the membrane-bound transport "B" subunit. Pertussis toxin is an exotoxin with six subunits (named S1 through S5—each complex contains two copies of S4). The subunits are arranged in A-B structure: the A component is enzymatically active and is formed from the S1 subunit, while the B component is the receptor-binding portion and is made up of subunits S2–S5. The subunits are encoded by ptx genes encoded on a large PT operon that also includes additional genes that encode Ptl proteins. Together, these proteins form the PT secretion complex. | 1 | Gene expression + Signal Transduction |
There are three classes of SMADs:
# Receptor-regulated SMAD (R-SMAD)
# Common-mediator SMAD (Co-SMAD)
# Inhibitory SMAD (I-SMAD)
Examples of SMADs in each class:
The TGF-β superfamily activates members of the SMAD family, which function as transcription factors. Specifically, the type I receptor, activated by the type II receptor, phosphorylates R-SMADs that then bind to the co-SMAD, SMAD4. The R-SMAD/Co-SMAD forms a complex with importin and enters the nucleus, where they act as transcription factors and either up-regulate or down-regulate in the expression of a target gene.
Specific TGF-β ligands will result in the activation of either the SMAD2/3 or the SMAD1/5 R-SMADs. For instance, when activin, Nodal, or TGF-β ligand binds to the receptors, the phosphorylated receptor complex can activate SMAD2 and SMAD3 through phosphorylation. However, when a BMP ligand binds to the receptors, the phosphorylated receptor complex activates SMAD1 and SMAD5. Then, the Smad2/3 or the Smad1/5 complexes form a dimer complex with SMAD4 and become transcription factors. Though there are many R-SMADs involved in the pathway, there is only one co-SMAD, SMAD4. | 1 | Gene expression + Signal Transduction |
The cementation process is an obsolete technology for making steel by carburization of iron. Unlike modern steelmaking, it increased the amount of carbon in the iron. It was apparently developed before the 17th century. Derwentcote Steel Furnace, built in 1720, is the earliest surviving example of a cementation furnace. Another example in the UK is the cementation furnace in Doncaster Street, Sheffield. | 0 | Metallurgy |
Brinelling is the permanent indentation of a hard surface. It is named after the Brinell scale of hardness, in which a small ball is pushed against a hard surface at a preset level of force, and the depth and diameter of the mark indicates the Brinell hardness of the surface. Brinelling is permanent plastic deformation of a surface, and usually occurs while two surfaces in contact are stationary (such as rolling elements and the raceway of a bearings) and the material yield strength has been exceeded.
Brinelling is undesirable, as the parts often mate with other parts in very close proximity. The very small indentations can quickly lead to improper operation, such as chattering or excess vibration, which in turn can accelerate other forms of wear, such as spalling and ultimately, failure of the bearing. | 0 | Metallurgy |
Thermocouples of platinum/molybdenum-alloy (95%Pt/5%Mo–99.9%Pt/0.1%Mo, by weight) are sometimes used in nuclear reactors, since they show a low drift from nuclear transmutation induced by neutron irradiation, compared to the platinum/rhodium-alloy types. | 0 | Metallurgy |
Available coatings include polyesters, plastisols, polyurethanes, polyvinylidene fluorides (PVDF), epoxies, primers, backing coats and laminate films. For each product, the coating is built up in a number of layers.
Primer coatings form the essential link between the pretreatment and the finish coating. Essentially, a primer is required to provide inter-coat adhesion between the pretreatment and the finish coat and is also required to promote corrosion resistance in the total system. The composition of the primer will vary depending on the type of finish coat used. Primers require compatibility with various pretreatments and top coat paint systems; therefore, they usually comprise a mixture of resin systems to achieve this end.
Backing coats are applied to the underside of the strip with or without a primer. The coating is generally not as thick as the finish coating used for exterior applications. Backing coats are generally not exposed to corrosive environments and not visible in the end application. | 0 | Metallurgy |
NCOA4 has been shown to interact with:
* Androgen receptor, and
* Peroxisome proliferator-activated receptor gamma
* Ferritin
* ATG8 | 1 | Gene expression + Signal Transduction |
ASM has been in existence, under various names, since 1913, when it began as a local club in Detroit called the Steel Treaters Club. During World War I, the Steel Treaters Club became the Steel Treating Research Society, with groups in Detroit, Chicago, and Cleveland. After World War I, the Chicago group seceded and formed the American Steel Treaters Society.
In 1920 the local chapters were reunified into the new American Society for Steel Treating (ASST). The society expanded its technical scope beyond steel during the 1920s. In 1933 it became the American Society for Metals (ASM).
Gradually the society expanded its geographic scope beyond the U.S. and its technical scope beyond metals to include other materials. It became known as ASM International in 1986. , ASM claims 20,000 members worldwide.
ASM provides several information resources, including technical journals, books, and databases. ASM also hosts numerous international conferences each year, including ASM's Annual Meeting: International Materials, Applications, and Technologies Conference and Exposition (IMAT). | 0 | Metallurgy |
In a first step FAIRE-seq data are mapped to the reference genome of the model organism used.
Next, the identification of genomic regions with open chromatin, is done by using a peak calling algorithm. Different tools offer packages to do this (e.g. ChIPOTle ZINBA and MACS2). ChIPOTle uses a sliding window of 300bp to identify statistically significant signals. In contrast, MACS2 identifies the enriched signal by combining the parameter callpeak with other options like broad, broad cutoff, no model or shift. ZINBA is a generic algorithm for detection of enrichment in short read dataset. It thus helps in the accurate detection of signal in complex datasets having low signal-to noise ratio.
BedTools is used to merge the enriched regions residing close to each other to form COREs (Cluster of open regulatory elements). This helps in the identification of chromatin accessible regions and gene regulation patterns which would have been undetectable otherwise, considering the lower resolution FAIRE-seq often brings with it.
Data is typically visualized as tracks (e.g. bigWig) and can be uploaded to the UCSC genome browser.
The major limitation of this method, i.e. the low signal-to-noise ratio compared to other chromatin accessibility assays, makes the computational interpretation of these data very difficult. | 1 | Gene expression + Signal Transduction |
The iron-tin intermetallic forms at around and naturally assumes a kagome structure. Quenching in an ice bath then cools the material to room temperature without disrupting the atomic structure. | 0 | Metallurgy |
A chromatin variant corresponds to a section of the genome that differs in chromatin states across cell types/states within an individual (intra-individual) or between individuals for a given cell type/state (inter-individual). Chromatin variants distinguish DNA sequences that differ in their function in one cell type/state versus another. Chromatin variants are found across the genome, inclusive of repetitive and non-repetitive DNA sequence. Chromatin variants range in sizes. The smallest chromatin variants cover a few hundred DNA base pairs, such as seen at promoters, enhancers or insulators. The largest chromatin variants capture a few thousand DNA base pairs, such as seen at Large Organized Chromatin Lysine domains (LOCKs) and Clusters Of Cis-Regulatory Elements (COREs), such as super-enhancer. | 1 | Gene expression + Signal Transduction |
In proliferating cells, certain pRb conformations (when RxL motif if bound by protein phosphatase 1 or when it is acetylated or methylated) are resistant to CDK phosphorylation and retain other function throughout cell cycle progression, suggesting not all pRb in the cell are devoted to guarding the G1/S transition.
Studies have also demonstrated that hyperphosphorylated pRb can specifically bind E2F1 and form stable complexes throughout the cell cycle to carry out unique unexplored functions, a surprising contrast from the classical view of pRb releasing E2F factors upon phosphorylation.
In summary, many new findings about pRb's resistance to CDK phosphorylation are emerging in pRb research and shedding light on novel roles of pRb beyond cell cycle regulation. | 1 | Gene expression + Signal Transduction |
Because these alloys are intended for high temperature applications their creep and oxidation resistance are of primary importance. Nickel (Ni)-based superalloys are the material of choice for these applications because of their unique γ' precipitates. The properties of these superalloys can be tailored to a certain extent through the addition of various other elements, common or exotic, including not only metals, but also metalloids and nonmetals; chromium, iron, cobalt, molybdenum, tungsten, tantalum, aluminium, titanium, zirconium, niobium, rhenium, yttrium, vanadium, carbon, boron or hafnium are some examples of the alloying additions used. Each addition serves a particular purpose in optimizing properties.
Creep resistance is dependent, in part, on slowing the speed of dislocation motion within a crystal structure. In modern Ni-based superalloys, the γ-Ni(Al,Ti) phase acts as a barrier to dislocation. For this reason, this γ; intermetallic phase, when present in high volume fractions, increases the strength of these alloys due to its ordered nature and high coherency with the γ matrix. The chemical additions of aluminum and titanium promote the creation of the γ phase. The γ phase size can be precisely controlled by careful precipitation strengthening heat treatments. Many superalloys are produced using a two-phase heat treatment that creates a dispersion of cuboidal γ particles known as the primary phase, with a fine dispersion between these known as secondary γ. In order to improve the oxidation resistance of these alloys, Al, Cr, B, and Y are added. The Al and Cr form oxide layers that passivate the surface and protect the superalloy from further oxidation while B and Y are used to improve the adhesion of this oxide scale to the substrate. Cr, Fe, Co, Mo and Re all preferentially partition to the γ matrix while Al, Ti, Nb, Ta, and V preferentially partition to the γ' precipitates and solid solution strengthen the matrix and precipitates respectively. In addition to solid solution strengthening, if grain boundaries are present, certain elements are chosen for grain boundary strengthening. B and Zr tend to segregate to the grain boundaries which reduces the grain boundary energy and results in better grain boundary cohesion and ductility. Another form of grain boundary strengthening is achieved through the addition of C and a carbide former, such as Cr, Mo, W, Nb, Ta, Ti, or Hf, which drives precipitation of carbides at grain boundaries and thereby reduces grain boundary sliding. | 0 | Metallurgy |
While the Toll and Imd signalling pathways of Drosophila are commonly depicted as independent for explanatory purposes, the underlying complexity of Imd signalling involves a number of likely mechanisms wherein Imd signalling interacts with other signalling pathways including Toll and JNK. While the paradigm of Toll and Imd as largely independent provides a useful context for the study of immune signalling, the universality of this paradigm as it applies to other insects has been questioned. In Plautia stali stinkbugs, suppression of either Toll or Imd genes simultaneously leads to reduced activity of classic Toll and Imd effectors from both pathways. | 1 | Gene expression + Signal Transduction |
Amongst the other newly steel-producing countries, in 2017 South Korea produces 71 million tonnes, nearly double Germany; and Brazil 34 million tonnes; all three countries have not changed much since 2011.
Indian steel production in 2017 is just over 100 million tonnes; up substantially from 70 million tonnes in 2011 – compared to only 1 million tonnes at the time of its independence in 1947. By 1991, when the economy was opened up steel production grew to around 14 million tonnes. Thereafter, it doubled in the next 10 years, and then it is doubling again, maybe over a slightly longer span.
The world steel industry flattened from 2007 to 2009 at 1,300 million tonnes, before rising again, due to worldwide recession starting in 2008, with its heavy cutbacks in construction, sharply lowered demand and prices falling 40%.
Showing the impact of that plateau, in 2007 ThyssenKrupp spent $12 billion to build the two most modern mills in the world, situated in Alabama and Brazil. They lost $11 billion on the new plants, which sold steel below the cost of production. Finally in 2013, the plants were sold at under $4 billion.
Nowadays, the steel industry is on the edge of a major technological evolution to deal with the huge amounts of CO produced in the conventional steelmaking process. The use of blast furnaces and basic oxygen furnace produces around 1.8 ton of CO per ton of steel produced. In order to reach the climate objectives as stated in the Paris Climate Agreement, the European Green Deal, etc., the steel industry will have to implement carbon capture and sequestration or carbon capture and utilization technology or change to less conventional steelmaking technologies such as the electric arc furnace route. Other alternatives are the use of biomass, plastic waste or hydrogen as reducing agent in the blast furnace instead of coal. | 0 | Metallurgy |
Clinker often is reused as a cheap material for paving footpaths. It is laid and rolled, and forms a hard path with a rough surface that presents less risk of slipping than most loose materials. In sufficient thickness such a layer drains well and is valuable for controlling muddiness. However, if laid without sufficient adhesive, it needs frequent rolling and addition of more clinker to maintain the path in good condition if it is subject to heavy foot traffic.
In sewage treatment works, the foul water is first screened to remove floating debris. Then it is sedimented to remove insoluble particles. After this, it is sprayed over a filter bed of clinker. Aerobic microbes soon grow in hollows in the clinker, where they kill harmful anaerobic bacteria in the water and remove much of the offensive organic waste.
Historically, clinker from coal-burning steamships simply was discarded overboard, leaving detectable trails on the seabed of some prominent steamship routes. As such, the deposits have proven to be of biological, historical and archaeological interest.
Naturally occurring clinkers exist. For example, in the Powder River Basin is covered by clinkers from coal-seam fires, i.e., "baked, welded and molded rocks formed by the natural burning of coal beds." | 0 | Metallurgy |
Immunoglobulin-like receptors are members of the immunoglobulin superfamily and have one or more 70-110 residue immunoglobulin domains (Ig) in their extracellular region, typically multiple such domains in tandem. Many of the genes encoding these proteins occur in the leukocyte receptor complex (LRC), a large gene cluster on human chromosome 19. Members of this group found in the human genome include:
* The killer-cell immunoglobulin-like receptor (KIR) family contains proteins with 2-3 extracellular Ig domains and long (inhibitory) or short (activating) cytoplasmic regions. Typically expressed in NK and some T cells, they interact with MHC class I. This gene family located in the LRC is highly polymorphic and there is individual variation in both alleles and copy number, as well as in alternative splicing. This family has undergone significant diversification in primate lineages.
* The leukocyte immunoglobulin-like receptors (LILR) family contains 13 genes, including two pseudogenes. They have 2-4 Ig domains. One member, LILRA3, lacks a transmembrane region and is a soluble protein; others may be expressed in soluble form through alternative splicing. Like the similar KIR family, LILR genes are found in the LRC and are polymorphic, though less so than KIR. LILR proteins are broadly expressed in immune cells and have very diverse ligands.
* The paired type 2 immunoglobulin like receptor (PILR) family contains two genes, PILRA (inhibiting) and PILRB (activating). They have a single extracellular Ig domain with a siglec-like structure.
* The signal regulatory protein (SIRP) family contains three genes, SIRPA (inhibiting), SIRPB1 (activating), and SIRPG (non-signaling), with the more distantly related SIRPD and SIRPB2 not yet well characterized. SIRPA interacts with CD47, a regulator of phagocytosis. This family also interacts with surfactant protein D.
* The carcinoembryonic antigen-related cell adhesion (CEACAM) family contains 12 genes with one or more Ig domains. They are expressed broadly, especially in endothelium and epithelium and have roles in cell-cell recognition. They have been extensively studied for their role in cancer and have been used as cancer biomarkers.
* The siglec family contains 15 genes divided into two evolutionarily related groups. This family has three members with activating motifs, Siglec-14, Siglec-15, and Siglec-16. These proteins bind sialic acids, and are often targeted by pathogens.
* TIGIT (T cell immunoreceptor with Ig and ITIM domains) is an inhibitory receptor that forms a nonhomologous but functional pair with DNAM1 (CD226). | 1 | Gene expression + Signal Transduction |
Fretting resistance is not an intrinsic property of a material, or even of a material couple. There are several factors affecting fretting behavior of a contact:
* Contact load
* Sliding amplitude
* Number of cycles
* Temperature
* Relative humidity
* Inertness of materials
* Corrosion and resulting motion-triggered contact insufficiency | 0 | Metallurgy |
The element is named after ytterbite, a mineral first identified in 1787 by the chemist Carl Axel Arrhenius. He named the mineral after the village of Ytterby, in Sweden, where it had been discovered. When one of the chemicals in ytterbite was later found to be a previously unidentified element, the element was then named yttrium after the mineral. | 0 | Metallurgy |
The , developed in 1908 with Elias Anton Cappelen Smith, significantly improved the converting of copper matte.
Before this invention, the converter was a cylindrical barrel, lined with an acid refractory lining, made of sand and clay. It was developed by two French engineers, Pierre Manhès and from 1880 to 1884. Their copper-converting process, named the Manhès–David process, was directly derived from the Bessemer process. In this horizontal chemical reactor, where air was injected into copper matte, a molten sulfide material containing iron, sulphur and copper, to become molten blister, an alloy containing 99% copper. But the basic slag produced during the blowing combined with the acid silica refractory lining, thereby causing a very short lifetime of the lining.
By developing a basic refractory material adapted to the matte refining process (in magnesia bricks), Peirce and his engineer Smith found a way to drastically increase the lifetime of the lining. It has been stated that, in some cases, the process allowing an increase from 10 to 2500 tons of copper produced without relining the converters. A reduction of the cost of copper converting from 15–20 USD to 4–5 USD has been stated.
The Peirce-Smith converter quickly replaced the Manhès–David converter: by March 1912, the Peirce-Smith Converting Co claimed that "over 80% of the copper produced in [the U.S.] is being converted either in P-S type converters or on basic lining, under license, in the old acid shells".
It is still in use today, although the process has been significantly improved since then. In 2010, with 250 converters working in the world, the Peirce-Smith converters refine 90% of the copper matte. | 0 | Metallurgy |
The alloy has the highest magnetostriction of any alloy, up to 0.002 m/m at saturation; it expands and contracts in a magnetic field. Terfenol-D has a large magnetostriction force, high energy density, low sound velocity, and a low Youngs modulus. At its most pure form, it also has low ductility and a low fracture resistance. Terfenol-D is a gray alloy that has different possible ratios of its elemental components that always follow a formula of . The addition of dysprosium made it easier to induce magnetostrictive responses by making the alloy require a lower level of magnetic fields. When the ratio of Tb and Dy is increased, the resulting alloys magnetostrictive properties will operate at temperatures as low as −200 °C, and when decreased, it may operate at a maximum of 200 °C. The composition of Terfenol-D allows it to have a large magnetostriction and magnetic flux when a magnetic field is applied to it. This case exists for a large range of compressive stresses, with a trend of decreasing magnetostriction as the compressive stress increases. There is also a relationship between the magnetic flux and compression in which when the compressive stress increases, the magnetic flux changes less drastically. Terfenol-D is mostly used for its magnetostrictive properties, in which it changes shape when exposed to magnetic fields in a process called magnetization. Magnetic heat treatment is shown to improve the magnetostrictive properties of Terfenol-D at low compressive stress for certain ratios of Tb and Dy. | 0 | Metallurgy |
Promoter activity is a term that encompasses several meanings around the process of gene expression from regulatory sequences —promoters and enhancers. Gene expression has been commonly characterized as a measure of how much, how fast, when and where this process happens. Promoters and enhancers are required for controlling where and when a specific gene is transcribed.
Traditionally the measure of gene products (i.e. mRNA, proteins, etc.) has been the major approach of measure promoter activity. However, this method confront with two issues: the stochastic nature of the gene expression and the lack of mechanistic interpretation of the thermodynamical process involved in the promoter activation.
The actual developments in metabolomics product of developments of next-generation sequencing technologies and molecular structural analysis have enabled the development of more accurate models of the process of promoter activation (e.g. the sigma structure of the polymerase holoenzyme domains) and a better understanding of the complexities of the regulatory factors involved. | 1 | Gene expression + Signal Transduction |
NaK has been used as the coolant in experimental fast neutron nuclear reactors. Unlike commercial plants, these are frequently shut down and defuelled. Use of lead or pure sodium, the other materials used in practical reactors, would require continual heating to maintain the coolant as a liquid. Use of NaK overcomes this. The Dounreay Fast Reactor is an example.
The Soviet RORSAT radar satellites were powered by a BES-5 reactor, which was cooled with NaK. In addition to the wide liquid temperature range, NaK has a very low vapor pressure, which is important in the vacuum of space.
An unintended consequence of the usage as a coolant on orbiting satellites has been the creation of additional space debris. NaK coolant has leaked from a number of satellites, including Kosmos 1818 and Kosmos 1867. The coolant self-forms into droplets of sodium–potassium of up to several centimeters in size. These objects are space debris.
The Danamics LMX Superleggera CPU cooler uses NaK to transport heat from the CPU to its cooling fins. | 0 | Metallurgy |
Recombination hotspots are DNA sequences that increase local recombination. The HOT1 sequence in yeast is one of the most well studied mitotic recombination hotspots. The HOT1 sequence includes an RNA polymerase I transcription promoter. In a yeast mutant strain defective in RNA polymerase I the HOT1 activity in promoting recombination is abolished. The level of RNA polymerase I transcription activity that is dependent on the promoter in the HOT1 sequence appears to determine the level of nearby mitotic recombination. | 1 | Gene expression + Signal Transduction |
Mineral processing begins with beneficiation, consisting of initially breaking down the ore to required sizes depending on the concentration process to be followed, by crushing, grinding, sieving etc. Thereafter, the ore is physically separated from any unwanted impurity, depending on the form of occurrence and or further process involved. Separation processes take advantage of physical properties of the materials. These physical properties can include density, particle size and shape, electrical and magnetic properties, and surface properties. Major physical and chemical methods include magnetic separation, froth flotation, leaching etc., whereby the impurities and unwanted materials are removed from the ore and the base ore of the metal is concentrated, meaning the percentage of metal in the ore is increased. This concentrate is then either processed to remove moisture or else used as is for extraction of the metal or made into shapes and forms that can undergo further processing, with ease of handling.
Ore bodies often contain more than one valuable metal. Tailings of a previous process may be used as a feed in another process to extract a secondary product from the original ore. Additionally, a concentrate may contain more than one valuable metal. That concentrate would then be processed to separate the valuable metals into individual constituents. | 0 | Metallurgy |
A spectacular example of galvanic corrosion occurred in the Statue of Liberty when regular maintenance checks in the 1980s revealed that corrosion had taken place between the outer copper skin and the wrought iron support structure. Although the problem had been anticipated when the structure was built by Gustave Eiffel to Frédéric Bartholdi's design in the 1880s, the insulation layer of shellac between the two metals had failed over time and resulted in rusting of the iron supports. An extensive renovation was carried out with replacement of the original insulation with PTFE. The structure was far from unsafe owing to the large number of unaffected connections, but it was regarded as a precautionary measure to preserve a national symbol of the United States. | 0 | Metallurgy |
* TGFα is upregulated in some human cancers. It is produced in macrophages, brain cells, and keratinocytes, and induces epithelial development. It belongs to the EGF family.
* TGFβ exists in three known subtypes in humans, TGFβ1, TGFβ2, and TGFβ3. These are upregulated in Marfan's syndrome and some human cancers, and play crucial roles in tissue regeneration, cell differentiation, embryonic development, and regulation of the immune system. Isoforms of transforming growth factor-beta (TGF-β1) are also thought to be involved in the pathogenesis of pre-eclampsia. They belong to the transforming growth factor beta family. TGFβ receptors are single pass serine/threonine kinase receptors. | 1 | Gene expression + Signal Transduction |
Polishing is abrasion by free abrasives that are suspended in a lubricant and can roll or slide between the specimen and paper. Polishing erases grinding marks and smooths the specimen to a mirror-like finish. Polishing on a bare metallic platen is called lapping. A typical polishing sequence for ceramics is 5–10 minutes each on 15-, 6- and 1-µm diamond paste or slurry on napless paper rotating at 240 rpm. The specimen is again washed in an ultrasonic bath after each step. The three sets of specimens in Fig. 3 have been sawed, embedded, ground and polished. | 0 | Metallurgy |
The President of the United States is authorized to declare each May "Steelmark Month" to recognize the contribution made by the steel industry to the United States. | 0 | Metallurgy |
Countermeasures involve using alloys not susceptible to grain boundary depletion, using a suitable heat treatment, altering the environment (e.g. lowering oxygen content), and/or use cathodic protection. | 0 | Metallurgy |
Nitinol's unusual properties are derived from a reversible solid-state phase transformation known as a martensitic transformation, between two different martensite crystal phases, requiring of mechanical stress.
At high temperatures, nitinol assumes an interpenetrating simple cubic structure referred to as austenite (also known as the parent phase). At low temperatures, nitinol spontaneously transforms to a more complicated monoclinic crystal structure known as martensite (daughter phase). There are four transition temperatures associated to the austenite-to-martensite and martensite-to-austenite transformations. Starting from full austenite, martensite begins to form as the alloy is cooled to the so-called martensite start temperature, or M, and the temperature at which the transformation is complete is called the martensite finish temperature, or M. When the alloy is fully martensite and is subjected to heating, austenite starts to form at the austenite start temperature, A, and finishes at the austenite finish temperature, A.
The cooling/heating cycle shows thermal hysteresis. The hysteresis width depends on the precise nitinol composition and processing. Its typical value is a temperature range spanning about 20–50 °C (36–90 °F) but it can be reduced or amplified by alloying and processing.
Crucial to nitinol properties are two key aspects of this phase transformation. First is that the transformation is "reversible", meaning that heating above the transformation temperature will revert the crystal structure to the simpler austenite phase. The second key point is that the transformation in both directions is instantaneous.
Martensites crystal structure (known as a monoclinic, or B19 structure) has the unique ability to undergo limited deformation in some ways without breaking atomic bonds. This type of deformation is known as twinning, which consists of the rearrangement of atomic planes without causing slip, or permanent deformation. It is able to undergo about 6–8% strain in this manner. When martensite is reverted to austenite by heating, the original austenitic structure is restored, regardless of whether the martensite phase was deformed. Thus the shape of the high temperature austenite phase is "remembered," even though the alloy is severely deformed at a lower temperature.
A great deal of pressure can be produced by preventing the reversion of deformed martensite to austenite—from to, in many cases, more than . One of the reasons that nitinol works so hard to return to its original shape is that it is not just an ordinary metal alloy, but what is known as an intermetallic compound. In an ordinary alloy, the constituents are randomly positioned in the crystal lattice; in an ordered intermetallic compound, the atoms (in this case, nickel and titanium) have very specific locations in the lattice. The fact that nitinol is an intermetallic is largely responsible for the complexity in fabricating devices made from the alloy.
To fix the original "parent shape," the alloy must be held in position and heated to about . This process is usually called shape setting. A second effect, called superelasticity or pseudoelasticity, is also observed in nitinol. This effect is the direct result of the fact that martensite can be formed by applying a stress as well as by cooling. Thus in a certain temperature range, one can apply a stress to austenite, causing martensite to form while at the same time changing shape. In this case, as soon as the stress is removed, the nitinol will spontaneously return to its original shape. In this mode of use, nitinol behaves like a super spring, possessing an elastic range 10 to 30 times greater than that of a normal spring material. There are, however, constraints: the effect is only observed up to about 40 °C (72 °F) above the A temperature. This upper limit is referred to as M, which corresponds to the highest temperature in which it is still possible to stress-induce the formation of martensite. Below M, martensite formation under load allows superelasticity due to twinning. Above M, since martensite is no longer formed, the only response to stress is slip of the austenitic microstructure, and thus permanent deformation.
Nitinol is typically composed of approximately 50 to 51% nickel by atomic percent (55 to 56% weight percent). Making small changes in the composition can change the transition temperature of the alloy significantly. Transformation temperatures in nitinol can be controlled to some extent, where A temperature ranges from about . Thus, it is common practice to refer to a nitinol formulation as "superelastic" or "austenitic" if A is lower than a reference temperature, while as "shape memory" or "martensitic" if higher. The reference temperature is usually defined as the room temperature or the human body temperature ().
One often-encountered effect regarding nitinol is the so-called R-phase. The R-phase is another martensitic phase that competes with the martensite phase mentioned above. Because it does not offer the large memory effects of the martensite phase, it is usually of non practical use. | 0 | Metallurgy |
Typically the copper oxhide ingots are highly pure (approximately 99 weight percent copper) with trace element content of less than one weight percent. The few tin oxhide ingots that have been available to study are also exceptionally pure. Microscopic analysis of the Uluburun copper oxhide ingots reveals that they are highly porous. This feature results from the effervescence of gases as the molten metal cooled. Slag inclusions are also present. Their existence implies that slag was not fully removed from the smelted metal and thus that the ingots were made from remelted copper.
Macroscopic observation of the Uluburun copper ingots indicates that they were cast through multiple pours; there are distinct layers of metal in each ingot. Furthermore, the relatively high weight and high purity of the ingots would be difficult to achieve even today in only one pour.
The porosity of the copper ingots and the natural brittleness of tin suggest that both metal ingots were easy to break. As Bass et al. proposes, a metalsmith could simply break off a piece of the ingot whenever he liked for a new casting. | 0 | Metallurgy |
The techniques observed in all of them are quite similar. Basically they used the thermic alteration or firesetting (Mohen 1992, Craddock 1995, Eiroa et al. 1996, Timberlake 2003). This consists of applying fire to the rock and then pouring water over it: the rapid changes of temperature will cause cracks within the rocks that can be totally broken with the help of mauls and picks. Then the useful masses were selected, crushed and transported to the production centre that could be in the surrounding area (Mitterberg) or far away (Rudna Glava).
The mines were exploited in extremely efficient and clever ways, according to the technology available (Jovanovic 1980, Craddock 1995, Timberlake 2003). The entire convenient mineral was collected and the abandoned shafts carefully refilled with gangue and rocks (Mohen 1992; 85). For example, at Mount Gabriel, it was estimated that they extracted the astonishing number of of rock, gangue and ore. The usable amount of copper was 162.85 tonnes and the final smelting finished metal was 146.56 tonnes (Jackson 1980; 24). The entire process was thoroughly described in 1744 by Lewis Morris, Crown Mineral Agent for Cardiganshire, and, incidentally, antiquarian.
The tools employed are mainly presented in Lewis' observations, but other ones have been recovered in archaeological context:
*Stone tools: The most frequent find are the stone hammers, normally made of hard rocks accessible to the mine, beach or river pebbles. There is no standardization of these mauls but is common a system of hafting, usually a groove carved in the middle for where a rope was tied to the handle, like the twisted hazel recovered in Copa Hill.
* Antler and bone tools: Picks and scrapes made of bone and antlers have been found in the majority of the mines.
* Wood: Evidence of wooden tools are more infrequent. Nevertheless in places like Ai Bunar or Mount Gabriel were recovered shovels and wedges. A rudimentary system of stairs or scaffoldings can be supposed (Mohen 1992).
* Metal: The use of any metallic tool is rather strange and extraordinary. It seems that the copper was not used for the miners' tools. However copper chisels and discarded axes could be utilized as wedges.
* Other evidence: The presence of coal and charcoal, crucial for the firing (fire-setting) and furnace (fuel), is habitual. Leather sacks (at Ai Bunar) and shoulder baskets (at Copa Hill) were used to transport the crushed mineral. | 0 | Metallurgy |
CRTC2, initially called TORC2, is a transcriptional coactivator for the transcription factor CREB and a central regulator of
gluconeogenic gene expression in response to cAMP. CRTC2 is thought to drive tumorigenesis in STK11(LKB1)-null non-small cell lung cancers (NSCLC). | 1 | Gene expression + Signal Transduction |
The process is more environmentally friendly than traditional extraction methods. For the company this can translate into profit, since the necessary limiting of sulfur dioxide emissions during smelting is expensive. Less landscape damage occurs, since the bacteria involved grow naturally, and the mine and surrounding area can be left relatively untouched. As the bacteria breed in the conditions of the mine, they are easily cultivated and recycled.
Toxic chemicals are sometimes produced in the process. Sulfuric acid and H ions that have been formed can leak into the ground and surface water turning it acidic, causing environmental damage. Heavy ions such as iron, zinc, and arsenic leak during acid mine drainage. When the pH of this solution rises, as a result of dilution by fresh water, these ions precipitate, forming "Yellow Boy" pollution. For these reasons, a setup of bioleaching must be carefully planned, since the process can lead to a biosafety failure. Unlike other methods, once started, bioheap leaching cannot be quickly stopped, because leaching would still continue with rainwater and natural bacteria. Projects like Finnish Talvivaara proved to be environmentally and economically disastrous. | 0 | Metallurgy |
In melt spinning, the alloy or metal is first melted in a crucible. Then, an inert gas, usually argon, is used to jet the molten material out of a nozzle located on the underside of the crucible. The resulting stream of liquid is directed onto the outer circumferential surface of a rotating wheel or drum which is cooled internally. The drums outer surface is located extremely close to the nozzle but does not touch it. Generally, the velocity of the drums surface must be between 10 m/s and 60 m/s in order to avoid the formation of globules (droplets) or breaking the ribbon respectively. Once the stream contacts the drums surface, a small puddle of melt (molten material) is formed. Due to the low viscosity of the melt, the shear forces generated by the relative movement of the drums surface underneath the melt only extend a few microns into the puddle. In other words, only a small amount of the puddle is affected by the friction from the rotation of the drum. Consequently, as the drum spins, most of the melt puddle remains held between the nozzle and the drum by surface tension. However, the melt on the very bottom of the puddle, which is in direct contact with the drum, rapidly solidifies into a thin ribbon. The solidified ribbon is carried away from under the nozzle on the drums surface for up to 10° of rotation before centrifugal force from the drums rotation ejects it.
This process occurs continuously, so as solidified material is removed from underneath the puddle of melt, more liquid material is added to the puddle from the nozzle. | 0 | Metallurgy |
The flotation process is also widely used in industrial waste water treatment plants, where it removes fats, oil, grease and suspended solids from waste water. These units are called dissolved air flotation (DAF) units. In particular, dissolved air flotation units are used in removing oil from the wastewater effluents of oil refineries, petrochemical and chemical plants, natural gas processing plants and similar industrial facilities. | 0 | Metallurgy |
Adhesion GPCRs are found in fungi. They are believed to have evolved from the cAMP receptor family, arising approximately 1275 million years ago before the split of Unikonts from a common ancestor. Several fungi have novel adhesion GPCRs that have both short, 2–66 amino acid residues, and long, 312–4202 amino acid residues. Analysis of fungi showed that there were no secretin receptor family GPCRs, which suggests that they evolved from adhesion GPCRs in a later organism.
Genome analysis of the Teleost Takifugu rubripes has revealed that it has only two adhesion GPCRs that showed homology to Ig-hepta/GPR116. While the Fugu genome is relatively compact and limited with the number of adhesion GPCRs, Tetraodon nigroviridis, another species of puffer fish, has considerably more, totaling 29 adhesion GPCRs. | 1 | Gene expression + Signal Transduction |
The use of RNA-dependent RNA polymerase plays a major role in RNA interference in eukaryotes, a process used to silence gene expression via small interfering RNAs (siRNAs) binding to mRNA rendering them inactive. Eukaryotic RdRp becomes active in the presence of dsRNA, and is a less widely distributed compared to other RNAi components as it lost in some animals, though still found in C. elegans and P. tetraurelia and plants. This presence of dsRNA triggers the activation of RdRp and RNAi processes by priming the initiation of RNA transcription through the introduction of siRNAs into the system. In C. elegans, siRNAs are integrated into the RNA-induced silencing complex, RISC, which works alongside mRNAs targeted for interference to recruit more RdRps to synthesize more secondary siRNAs and repress gene expression. | 1 | Gene expression + Signal Transduction |
At the neurological level, behavior can be inferred based on hormone concentration, which in turn are influenced by hormone-release patterns; the numbers and locations of hormone receptors; and the efficiency of hormone receptors for those involved in gene transcription. Hormone concentration does not incite behavior, as that would undermine other external stimuli; however, it influences the system by increasing the probability of a certain event to occur.
Not only can hormones influence behavior, but also behavior and the environment can influence hormone concentration. Thus, a feedback loop is formed, meaning behavior can affect hormone concentration, which in turn can affect behavior, which in turn can affect hormone concentration, and so on. For example, hormone-behavior feedback loops are essential in providing constancy to episodic hormone secretion, as the behaviors affected by episodically secreted hormones directly prevent the continuous release of said hormones.
Three broad stages of reasoning may be used to determine if a specific hormone-behavior interaction is present within a system:
* The frequency of occurrence of a hormonally dependent behavior should correspond to that of its hormonal source.
* A hormonally dependent behavior is not expected if the hormonal source (or its types of action) is non-existent.
* The reintroduction of a missing behaviorally dependent hormonal source (or its types of action) is expected to bring back the absent behavior. | 1 | Gene expression + Signal Transduction |
Typically, the work-piece is immersed in a temperature-controlled bath of electrolyte and serves as the anode; it is connected to the positive terminal of a DC power supply, the negative terminal being attached to the cathode. A current passes from the anode, where metal on the surface is oxidised and dissolved in the electrolyte, to the cathode. At the cathode, a reduction reaction occurs, which normally produces hydrogen. Electrolytes used for electropolishing are most often concentrated acid solutions such as mixtures of sulfuric acid and phosphoric acid. Other electropolishing electrolytes reported in the literature include mixtures of perchloric acid with acetic anhydride (which has caused fatal explosions), and methanolic solutions of sulfuric acid.
To electropolish a rough surface, the protruding parts of a surface profile must dissolve faster than the recesses. This process, referred to as anodic leveling, can be subject to incorrect analysis when measuring the surface topography. Anodic dissolution under electropolishing conditions deburrs metal objects due to increased current density on corners and burrs.
Most importantly, successful electropolishing should operate under diffusion limited constant current plateau, achieved by following current dependence on voltage (polarisation curve), under constant temperature and stirring conditions. | 0 | Metallurgy |
The early Iron Age in China began before 1000 BCE, with the introduction of ironware, such as knives, swords, and arrowheads, from the west into Xinjiang, before it further diffused to Qinghai and Gansu. In 2008, two iron fragments were excavated at the Mogou site, in Gansu. They have been dated to the 14th century BCE, belonging to the period of Siwa culture. One of the fragments was made of bloomery iron rather than meteoritic iron. | 0 | Metallurgy |
The editing involves cytidine deaminase that deaminates a cytidine base into a uridine base. An example of C-to-U editing is with the apolipoprotein B gene in humans. Apo B100 is expressed in the liver and apo B48 is expressed in the intestines. In the intestines, the mRNA has a CAA sequence edited to be UAA, a stop codon, thus producing the shorter B48 form.
C-to-U editing often occurs in the mitochondrial RNA of flowering plants. Different plants have different degrees of C-to-U editing; for example, eight editing events occur in mitochondria of the moss Funaria hygrometrica, whereas over 1,700 editing events occur in the lycophytes Isoetes engelmanii. C-to-U editing is performed by members of the pentatricopeptide repeat (PPR) protein family. Angiosperms have large PPR families, acting as trans -factors for cis -elements lacking a consensus sequence; Arabidopsis has around 450 members in its PPR family. There have been a number of discoveries of PPR proteins in both plastids and mitochondria. | 1 | Gene expression + Signal Transduction |
In electroplating, the item to be coated is placed into a container containing a solution of one or more tin salts. The item is connected to an electrical circuit, forming the cathode (negative) of the circuit while an electrode typically of the same metal to be plated forms the anode (positive). When an electric current is passed through the circuit, metal ions in the solution are attracted to the item. To produce a smooth, shiny surface, the electroplated sheet is then briefly heated above the melting point of tin. Most of the tin-plated steel made today is then further electroplated with a very thin layer of chromium to prevent dulling of the surface from oxidation of the tin. | 0 | Metallurgy |
Point defects (as well as stationary dislocations, jogs, and kinks) present in a material create stress fields within a material that disallow traveling dislocations to come into direct contact. Much like two particles of the same electric charge feel a repulsion to one another when brought together, the dislocation is pushed away from the already present stress field. | 0 | Metallurgy |
Myristoylation not only diversifies the function of a protein, but also adds layers of regulation to it. One of the most common functions of the myristoyl group is in membrane association and cellular localization of the modified protein. Though the myristoyl group is added onto the end of the protein, in some cases it is sequestered within hydrophobic regions of the protein rather than solvent exposed. By regulating the orientation of the myristoyl group, these processes can be highly coordinated and closely controlled. Myristoylation is thus a form of "molecular switch."
Both hydrophobic myristoyl groups and "basic patches" (highly positive regions on the protein) characterize myristoyl-electrostatic switches. The basic patch allows for favorable electrostatic interactions to occur between the negatively charged phospholipid heads of the membrane and the positive surface of the associating protein. This allows tighter association and directed localization of proteins.
Myristoyl-conformational switches can come in several forms. Ligand binding to a myristoylated protein with its myristoyl group sequestered can cause a conformational change in the protein, resulting in exposure of the myristoyl group. Similarly, some myristoylated proteins are activated not by a designated ligand, but by the exchange of GDP for GTP by guanine nucleotide exchange factors in the cell. Once GTP is bound to the myristoylated protein, it becomes activated, exposing the myristoyl group. These conformational switches can be utilized as a signal for cellular localization, membrane-protein, and protein–protein interactions. | 1 | Gene expression + Signal Transduction |
Since the 1990s, pRb was known to be inactivated via phosphorylation. Until, the prevailing model was that Cyclin D- Cdk 4/6 progressively phosphorylated it from its unphosphorylated to its hyperphosphorylated state (14+ phosphorylations). However, it was recently shown that pRb only exists in three states: un-phosphorylated, mono-phosphorylated, and hyper-phosphorylated. Each has a unique cellular function.
Before the development of 2D IEF, only hyper-phosphorylated pRb was distinguishable from all other forms, i.e. un-phosphorylated pRb resembled mono-phosphorylated pRb on immunoblots. As pRb was either in its active “hypo-phosphorylated” state or inactive “hyperphosphorylated” state. However, with 2D IEF, it is now known that pRb is un-phosphorylated in G0 cells and mono-phosphorylated in early G1 cells, prior to hyper-phosphorylation after the restriction point in late G1. | 1 | Gene expression + Signal Transduction |
The insulator element that is found in the gypsy retrotransposon of Drosophila is one of several sequences that have been studied in detail. The gypsy insulator can be found in the 5 untranslated region (UTR) of the retrotransposon element. Gypsy' affects the expression of adjacent genes pending insertion into a new genomic location, causing mutant phenotypes that are both tissue specific and present at certain developmental stages. The insulator likely has an inhibitory effect on enhancers that control the spatial and temporal expression of the affected gene. | 1 | Gene expression + Signal Transduction |
Eukaryotic initiation factor 4F (eIF4F) is a heterotrimeric protein complex that binds the 5' cap of messenger RNAs (mRNAs) to promote eukaryotic translation initiation. The eIF4F complex is composed of three non-identical subunits: the DEAD-box RNA helicase eIF4A, the cap-binding protein eIF4E, and the large "scaffold" protein eIF4G. The mammalian eIF4F complex was first described in 1983, and has been a major area of study into the molecular mechanisms of cap-dependent translation initiation ever since. | 1 | Gene expression + Signal Transduction |
Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form. In order to convert a metal oxide or sulphide to a purer metal, the ore must be reduced physically, chemically, or electrolytically. Extractive metallurgists are interested in three primary streams: feed, concentrate (metal oxide/sulphide) and tailings (waste).
After mining, large pieces of the ore feed are broken through crushing or grinding in order to obtain particles small enough, where each particle is either mostly valuable or mostly waste. Concentrating the particles of value in a form supporting separation enables the desired metal to be removed from waste products.
Mining may not be necessary, if the ore body and physical environment are conducive to leaching. Leaching dissolves minerals in an ore body and results in an enriched solution. The solution is collected and processed to extract valuable metals. Ore bodies often contain more than one valuable metal.
Tailings of a previous process may be used as a feed in another process to extract a secondary product from the original ore. Additionally, a concentrate may contain more than one valuable metal. That concentrate would then be processed to separate the valuable metals into individual constituents. | 0 | Metallurgy |
In 1958, Frederick C. Frank and John S. Kasper, in their original work investigating many complex alloy structures, showed that non-icosahedral environments form an open-end network which they called the major skeleton, and is now identified as the declination locus. They came up with the methodology to pack asymmetric icosahedra into crystals using other polyhedra with larger coordination numbers. These coordination polyhedra were constructed to maintain topological close packing (TCP). | 0 | Metallurgy |
Laves phases are intermetallic phases that have composition AB and are named for Fritz Laves who first described them. The phases are classified on the basis of geometry alone. While the problem of packing spheres of equal size has been well-studied since Gauss, Laves phases are the result of his investigations into packing spheres of two sizes. Laves phases fall into three Strukturbericht types: cubic MgCu (C15), hexagonal MgZn (C14), and hexagonal MgNi (C36). The latter two classes are unique forms of the hexagonal arrangement, but share the same basic structure. In general, the A atoms are ordered as in diamond, hexagonal diamond, or a related structure, and the B atoms form tetrahedra around the A atoms for the AB structure.
Laves phases are of particular interest in modern metallurgy research because of their abnormal physical and chemical properties. Many hypothetical or primitive applications have been developed. However, little practical knowledge has been elucidated from Laves phase study so far.
A characteristic feature is the almost perfect electrical conductivity, but they are not plastically deformable at room temperature.
In each of the three classes of Laves phase, if the two types of atoms were perfect spheres with a size ratio of , the structure would be topologically tetrahedrally close-packed. At this size ratio, the structure has an overall packing volume density of 0.710. Compounds found in Laves phases typically have an atomic size ratio between 1.05 and 1.67. Analogues of Laves phases can be formed by the self-assembly of a colloidal dispersion of two sizes of sphere.
Laves phases are instances of the more general Frank-Kasper phases. | 0 | Metallurgy |
During heat treating, a blacksmith causes phase changes in the iron-carbon system to control the material's mechanical properties, often using the annealing, quenching, and tempering processes. In this context, the color of light, or "blackbody radiation", emitted by the workpiece is an approximate gauge of temperature. Temperature is often gauged by watching the color temperature of the work, with the transition from a deep cherry-red to orange-red ( to ) corresponding to the formation of austenite in medium and high-carbon steel. In the visible spectrum, this glow increases in brightness as temperature increases. When cherry-red, the glow is near its lowest intensity and may not be visible in ambient light. Hence blacksmiths usually austenitize steel in low-light conditions to accurately judge the color of the glow. | 0 | Metallurgy |
Henry Bolckow (1806–1878) and John Vaughan (1799–1868) were lifelong business partners, friends, and brothers-in-law. They established what became the largest of all Victorian era iron and steel companies, Bolckow Vaughan, in Middlesbrough. Bolckow brought financial acumen, and Vaughan brought ironmaking and engineering expertise. The two men trusted each other implicitly and "never interfered in the slightest degree with each other's work. Mr. Bolckow had the entire management of the financial department, while Mr. Vaughan as worthily controlled the practical work of the establishment." At its peak the firm was the largest steel producer in Britain, possibly in the world. | 0 | Metallurgy |
Because of their excellent characteristics and manufacturing methods, liquid metals are often used in wearable devices, medical devices, interconnected devices and so on.
Typical uses of liquid metals include thermostats, switches, barometers, heat transfer systems, and thermal cooling and heating designs. Uniquely, they can be used to conduct heat and/or electricity between non-metallic and metallic surfaces.
Liquid metal is sometimes used as a thermal interface material between coolers and processors because of its high thermal conductivity. The PlayStation 5 video game console uses liquid metal to help cool high temperatures inside the console. Liquid metal cooled reactors also use them.
Liquid metal can be used for wearable devices and for spare parts.
Liquid metal can sometimes be used for biological applications, i.e., making interconnects that flex without fatigue. As Galinstan is not particularly toxic, wires made from silicone with a core of liquid metal would be ideal for intracardiac pacemakers and neural implants where delicate brain tissue cannot tolerate a conventional solid implant. In fact, a wire constructed of this material can be stretched to 3 or even 5 times its length and still conduct electricity, returning to its original size and shape with no loss.
Due to their unique combination of high surface tension and fluidic deformability, liquid metals have been found to be a remarkable material for creating soft actuators. The force-generating mechanisms in liquid metal actuators are typically achieved by modulation of their surface tension. For instance, a liquid metal droplet can be designed to bridge two moving parts (e.g., in robotic systems) in such a way to generate contraction when the surface tension increases. The principles of muscle-like contraction in liquid metal actuators have been studied for their potential as a next-generation artificial muscle that offers several liquid-specific advantages over other solid materials. | 0 | Metallurgy |
GLD-2 primarily stabilizes mRNAs that are translationally repressed as well as it strongly promotes bulk polyadenylation. Surprisingly, those functions seem to have little impact on dynamizing efficient target mRNA translation, as it is an efficient Poly(A) Polymerase which helps developing polyadenylation activity. This activity is stimulated by its interaction with a putative RNA-binding protein: GLD-3. It is proposed by some studies that GLD-3 stimulates GLD-2 by recruiting it to the RNA. If so, then bringing GLD-2 to the RNA by other means also should stimulate its activity. | 1 | Gene expression + Signal Transduction |
The oxygen blast furnace (OBF) process has been extensively studied theoretically because of the potentials of promising energy conservation and emission reduction. This type may be the most suitable for use with CCS. The main blast furnace has of three levels; the reduction zone (), slag formation zone (), and the combustion zone ().
Blast furnaces are currently rarely used in copper smelting, but modern lead smelting blast furnaces are much shorter than iron blast furnaces and are rectangular in shape. Modern lead blast furnaces are constructed using water-cooled steel or copper jackets for the walls, and have no refractory linings in the side walls. The base of the furnace is a hearth of refractory material (bricks or castable refractory). Lead blast furnaces are often open-topped rather than having the charging bell used in iron blast furnaces.
The blast furnace used at the Nyrstar Port Pirie lead smelter differs from most other lead blast furnaces in that it has a double row of tuyeres rather than the single row normally used. The lower shaft of the furnace has a chair shape with the lower part of the shaft being narrower than the upper. The lower row of tuyeres being located in the narrow part of the shaft. This allows the upper part of the shaft to be wider than the standard. | 0 | Metallurgy |
In 2000, there were several lead-free assemblies and chip products initiatives being driven by the Japan Electronic Industries Development Association (JEIDA) and Waste Electrical and Electronic Equipment Directive (WEEE). These initiatives resulted in tin-silver-copper alloys being considered and tested as lead-free solder ball alternatives for array product assemblies.
In 2003, tin-silver-copper was being used as a lead-free solder. However, its performance was criticized because it left a dull, irregular finish and it was difficult to keep the copper content under control. In 2005, tin-silver-copper alloys constituted approximately 65% of lead-free alloys used in the industry and this percentage has been increasing. Large companies such as Sony and Intel switched from using lead-containing solder to a tin-silver-copper alloy. | 0 | Metallurgy |
Iberia (modern Spain and Portugal) was possibly the Roman province richest in mineral ore, containing deposits of gold, silver, copper, tin, lead, iron, and mercury). From its acquisition after the Second Punic War to the Fall of Rome, Iberia continued to produce a significant amount of Roman metals.
Britannia was also very rich in metals. Gold was mined at Dolaucothi in Wales, copper and tin in Cornwall, and lead in the Pennines, Mendip Hills and Wales. Significant studies have been made on the iron production of Roman Britain; iron use in Europe was intensified by the Romans, and was part of the exchange of ideas between the cultures through Roman occupation. It was the importance placed on iron by the Romans throughout the Empire which completed the shift from the few cultures still using primarily bronze into the Iron Age.
Noricum (modern Austria) was exceedingly rich in gold and iron, Pliny, Strabo, and Ovid all lauded its bountiful deposits. Iron was its main commodity, but alluvial gold was also prospected. By 15 BC, Noricum was officially made a province of the Empire, and the metal trade saw prosperity well into the fifth century AD. Some scholars believe that the art of iron forging was not necessarily created, but well developed in this area and it was the population of Noricum which reminded Romans of the usefulness of iron. For example, of the three forms of iron (wrought iron, steel, and soft), the forms which were exported were of the wrought iron (containing a small percentage of uniformly distributed slag material) and steel (carbonised iron) categories, as pure iron is too soft to function like wrought or steel iron.
Dacia, located in the area of Transylvania, was conquered in 107 AD in order to capture the resources of the region for Rome. The amount of gold that came into Roman possession actually brought down the value of gold. Iron was also of importance to the region. The difference between the mines of Noricum and Dacia was the presence of a slave population as a workforce. | 0 | Metallurgy |
An ISASMELT furnace is an upright-cylindrical shaped steel vessel that is lined with refractory bricks. There is a molten bath of slag, matte or metal (depending on the application) at the bottom of the furnace. A steel lance is lowered into the bath through a hole in the roof of the furnace, and air or oxygen-enriched air that is injected through the lance into the bath causes vigorous agitation of the bath.
Mineral concentrates or materials for recycling are dropped into the bath through another hole in the furnace roof or, in some cases, injected down the lance. These feed materials react with the oxygen in the injected gas, resulting in an intensive reaction in a small volume (relative to other smelting technologies).
ISASMELT lances contain one or more devices called "swirlers" that cause the injected gas to spin within the lance, forcing it against the lance wall, cooling it. The swirler consists of curved vanes around a central pipe forming an annular flow. They are designed to minimize pressure losses changing the angle from axial to tangential thus creating a strong vortex. The vortex helps mix liquids and solids with oxygen in the bath. The cooling effect results in a layer of slag "freezing" on the outside of the lance. This layer of solid slag protects the lance from the high temperatures inside the furnace. The tip of the lance that is submerged in the bath eventually wears out, and the worn lance is easily replaced with a new one when necessary. The worn tips are subsequently cut off and a new tip welded onto the lance body before it is returned to the furnace.
ISASMELT furnaces typically operate in the range of 1000–1200 °C, depending on the application. The refractory bricks that form the internal lining of the furnace protect the steel shell from the heat inside the furnace.
The products are removed from the furnace through one or more "tap holes" in a process called "tapping". This can be either continuous removal or in batches, with the tap holes being blocked with clay at the end of a tap, and then reopened by drilling or with a thermic lance when it is time for the next tap.
The products are allowed to separate in a settling vessel, such as a rotary holding furnace or an electric furnace.
While smelting sulfide concentrates, most of the energy needed to heat and melt the feed materials is derived from the reaction of oxygen with the sulfur and iron in the concentrate. However, a small amount of supplemental energy is required. ISASMELT furnaces can use a variety of fuels, including coal, coke, petroleum coke, oil and natural gas. The solid fuel can be added through the top of the furnace with the other feed materials, or it can be injected down the lance. Liquid and gaseous fuels are injected down the lance. | 0 | Metallurgy |
Lead isotope analysis is a technique for determining the source of ore in ancient smelting. Lead isotope composition is a signature of ore deposits and varies very little throughout the whole deposit. Also, lead isotope composition is unchanged in the smelting process.
The amount of each of the four stable isotopes of lead are used in the analysis. They are Pb, Pb, Pb and Pb. Ratios: Pb/Pb, Pb/Pb and Pb/Pb are measured by mass spectrometry. Apart from Pb, the lead isotopes are all products of the radioactive decay of uranium and thorium. When ore is deposited, uranium and thorium are separated from the ore. Thus, deposits formed in different geological periods will have different lead isotope signatures.
:::::::U →Pb
:::::::U →Pb
:::::::Th→Pb
For example, Hauptmann performed lead isotope analysis on slags from Faynan, Jordan. The resulting signature was the same as that from ores from the dolomite, limestone and shale deposits in the Wadi Khalid and Wadi Dana areas of Jordan. | 0 | Metallurgy |
In the Middle Bronze (MB) Age (end of 3rd–middle of 2nd millennium BCE) hundreds of metal objects were found. The development of more complex weapons (longer daggers, swords, complex battle axes, etc.) was possible by alloying the copper with arsenic or with tin. All the MBII weapons that were analyzed were made of copper alloyed either with tin (14%–2% Sn) or with arsenic (4.3%–0.5% As), sometimes with a mixture of both usually in low concentrations. These changes in the metal properties of weapons are also reflected in the composition of small objects, like toggle pins that were probably made mainly from re-melting of scrap. Lead (Pb) started to play a greater role as a major alloy for thick casts of copper-based objects, mainly of battle axes during this period.
Although two definite major alloying compositions for the production of MBII copper-based artifacts, (1)copper with arsenic and (2) copper with tin, are detected, to date no visible connection of specific alloy with specific type of object or different periods has been seen: both alloys appear in similar objects and in burials dated to the beginning as well as to later parts of the ca. 400 years of the MBII age. Currently, there is no visible correlation between any specific alloying tradition and the spatial distribution of finds, as well. Similar objects made of arsenical coppers and of tin bronze were found in the same geographic region and identical objects with similar metal composition were found in distant areas like Palestine and Upper Egypt. The difference in the overall alloying pattern curve in Jericho and in Tell El-Dab'a shown by Philip (1995) does not necessarily have to be related to two different production centers, but could as well be the result of comparing different groups of objects (i.e., more prestigious weapons of control alloying either with tin or with arsenic) at Tell El Dab’a and similar objects mixed with simpler copper-based ones (like simple daggers, knives, toggle pins, etc.) in Jericho and/or types like the spearheads that have more mixed, low levels of both alloys.
The examination of metal composition in the formation of different types does add knowledge concerning production modes. The thicker the object is, the more lead was
deliberately added to the cast. The highest amounts of lead were measured in the duckbill axes, less in the flat socketed axes, and much less in thinner blades like spears and daggers, which were much more worked and annealed after being cast. This observation corresponds well with the controlled alloying of the duckbill axes and ribbed daggers (with much less lead in the latter) from the MBIIa, but does not correspond with the spears. Although they are derived mainly from MBIIa contexts, their composition is less controlled and more varied. There might be a connection between the level of allowing control and the investment in the cast — the more complex types, like duckbill and flat socketed axes and ribbed daggers, are usually cast in steatite, two-piece closed and well-carved moulds.
On the other hand, some of the less controlled alloyed types, like spearheads and knives as well as more simple tools such as chisel points, were mainly cast into open, relatively roughly carved limestone moulds. | 0 | Metallurgy |
Calmodulin's ability to recognize a tremendous range of target proteins is due in large part to its structural flexibility. In addition to the flexibility of the central linker domain, the N- and C-domains undergo open-closed conformational cycling in the Ca-bound state. Calmodulin also exhibits great structural variability, and undergoes considerable conformational fluctuations, when bound to targets. Moreover, the predominantly hydrophobic nature of binding between calmodulin and most of its targets allows for recognition of a broad range of target protein sequences. Together, these features allow calmodulin to recognize some 300 target proteins exhibiting a variety of CaM-binding sequence motifs. | 1 | Gene expression + Signal Transduction |
Bacterial recombination undergoes various different processes. The processes include: transformation, transduction, conjugation and homologous recombination. Homologous recombination relies on cDNA transferring genetic material. Complementary DNA sequences transport genetic material in the identical homologous chromosomes. The paternal and maternal paired chromosomes will align in order for the DNA sequences to undergo the process of crossing over. Transformation involves the uptake of exogenous DNA from the encircling environment. DNA fragments from a degraded bacterium will transfer into the surrounding, competent bacterium resulting in an exchange of DNA from the recipient. Transduction is associated with viral-mediated vectors transferring DNA material from one bacterium to another within the genome. Bacterial DNA is placed into the bacteriophage genome via bacterial transduction. In bacterial conjugation, DNA is transferred via cell-to-cell communication. Cell-to-cell communication may involve plasmids that allow for the transfer of DNA into another neighboring cell. The neighboring cells absorb the F-plasmid (fertility plasmid: inherited material that is present in the chromosome). The recipient and donor cell come into contact during a F-plasmid transfer. The cells undergo horizontal gene transfer in which the genetic material is transferred.
Mechanisms for double-stranded breaks
The RecBCD pathway in homologous recombination repairs the double-strand breaks in DNA that has degraded in bacteria. Base pairs attached to the DNA strands go through an exchange at a Holliday junction. In the second step of bacterial recombination, branch migration. involves the base pairs of the homologous DNA strands to continuously be interchanged at a Holliday junction. This results in the formation of two DNA duplexes. The RecBCD pathway undergoes helicase activity by unzipping the DNA duplex and stops when the nucleotide sequence reaches 5′-GCTGGTGG-3′. This nucleotide sequence is known as the Chi site. RecBCD enzymes will change after the nucleotide sequence reaches the Chi site. The RecF pathway repairs the degradation of the DNA strands. | 1 | Gene expression + Signal Transduction |
Crack extension, as opposed to crack onset, is the rate determining step for solid induced-metal embrittlement. The main mechanism leading to solid metal induced embrittlement is multilayer surface self-diffusion of the embrittler at the crack tip. Propagation rate of a crack undergoing metal-induced embrittlement is a function of the supply of embrittler present at the crack tip. Crack velocities in SMIE are much slower than LMIE velocities. Catastrophic failure of a material via SMIE occurs as a result of the propagation of cracks to a critical point. To this end, the propagation of the crack is controlled by the transport rate and mechanisms of the embrittler at the tip of nucleated cracks. SMIE can be mitigated by increasing the tortuosity of crack paths such that resistance to intergranular cracking increases. | 0 | Metallurgy |
The transition to the Late Bronze Age brought societal change to the British Isles, and also apparently increased availability of gold, which led to a trend to much larger and more massive pieces. The largest were jewellery worn round the neck in a range of styles, the most ostentatious wide flat collars or gorgets with ribbed decoration following the shape of the piece, and round discs at the side. The Mold Cape is unique among survivals, but fits in with the trend to massive pieces emphasizing the neck and chest. It was clearly not for prolonged wear, as the wearer could not raise their arms. In Ireland, lunulae were probably replaced as neck ornaments firstly by gold torcs, found from the Irish Middle Bronze Age, and then in the Late Bronze Age by the spectacular "gorgets" of thin ribbed gold, some with round discs at the side, of which 9 examples survive, 7 in the National Museum of Ireland.
Designs based on twisted bars or ribbons giving a spiral became popular, probably influenced by the Continent. "Although over 110 identifiable British [includes Ireland] ribbon torcs are known, the dating of these simple, flexible ornaments is elusive", perhaps indicating "a long-lived preference for ribbon torcs, which continued for over 1,000 years", into the Iron Age. | 0 | Metallurgy |
Generally, in progression to cancer, hundreds of genes are silenced or activated. Although silencing of some genes in cancers occurs by mutation, a large proportion of carcinogenic gene silencing is a result of altered DNA methylation (see DNA methylation in cancer). DNA methylation causing silencing in cancer typically occurs at multiple CpG sites in the CpG islands that are present in the promoters of protein coding genes.
Altered expressions of microRNAs also silence or activate many genes in progression to cancer (see microRNAs in cancer). Altered microRNA expression occurs through hyper/hypo-methylation of CpG sites in CpG islands in promoters controlling transcription of the microRNAs.
Silencing of DNA repair genes through methylation of CpG islands in their promoters appears to be especially important in progression to cancer (see methylation of DNA repair genes in cancer). | 1 | Gene expression + Signal Transduction |
In the 1920s Davenport and Bain discovered a new steel microstructure which they provisionally called martensite-troostite, due to it being intermediate between the already known low-temperature martensite phase and what was then known as troostite (now fine-pearlite). This microstructure was subsequently named bainite by Bain's colleagues at the United States Steel Corporation, although it took some time for the name to be taken up by the scientific community with books as late as 1947 failing to mention bainite by name.
Bain and Davenport also noted the existence of two distinct forms: upper-range bainite which formed at higher temperatures and lower-range bainite which formed near the martensite start temperature (these forms are now known as upper- and lower-bainite respectively). The early terminology was further confused by the overlap, in some alloys, of the lower-range of the pearlite reaction and the upper-range of the bainite with the additional possibility of proeutectoid ferrite. | 0 | Metallurgy |
TRIM33 acts as a tumor suppressor gene preventing the development chronic myelomonocytic leukemia.
TRIM33 regulates also the TRIM28 receptor and promotes physiological aging of hematopoietic stem cells.
TRIM33 acts as an oncogene by preventing apoptosis in B-cell leukemias. | 1 | Gene expression + Signal Transduction |
The full 3D representation of crystallographic texture is given by the orientation distribution function (ODF) which can be achieved through evaluation of a set of pole figures or diffraction patterns. Subsequently, all pole figures can be derived from the ODF.
The ODF is defined as the volume fraction of grains with a certain orientation .
The orientation is normally identified using three Euler angles. The Euler angles then describe the transition from the sample’s reference frame into the crystallographic reference frame of each individual grain of the polycrystal. One thus ends up with a large set of different Euler angles, the distribution of which is described by the ODF.
The orientation distribution function, ODF, cannot be measured directly by any technique. Traditionally both X-ray diffraction and EBSD may collect pole figures. Different methodologies exist to obtain the ODF from the pole figures or data in general. They can be classified based on how they represent the ODF. Some represent the ODF as a function, sum of functions or expand it in a series of harmonic functions. Others, known as discrete methods, divide the ODF space in cells and focus on determining the value of the ODF in each cell. | 0 | Metallurgy |
Rapamycin and rapalogs (rapamycin derivatives) are small molecule inhibitors, which have been evaluated as anticancer agents. The rapalogs have more favorable pharmacokinetic profile compared to rapamycin, the parent drug, despite the same binding sites for mTOR and FKBP12. | 1 | Gene expression + Signal Transduction |
The Australasian Institute of Mining and Metallurgy (AusIMM) provides services to professionals engaged in all facets of the global minerals sector and is based in Carlton, Victoria, Australia. | 0 | Metallurgy |
Strader and colleagues designed the first GPCR which could be activated only by a synthetic compound and has gradually been gaining momentum. The first international RASSL meeting was scheduled for April 6, 2006. A simple example of the use of a RASSL system in behavioral genetics was illustrated by Mueller et al. (2005) where they showed that expressing a RASSL receptor in sweet taste cells of the mouse tongue led to a strong preference for oral consumption of the synthetic ligand, whereas expressing the RASSL in bitter taste cells caused dramatic taste aversion for the same compound.
The attenuating effects of the hM4Di-DREADD were originally explored in 2007, before being confirmed in 2014. | 1 | Gene expression + Signal Transduction |
In eukaryotes, ribosomal rRNA and the tRNAs involved in translation are controlled by RNA polymerase I (Pol I) and RNA polymerase III (Pol III) . RNA Polymerase II (Pol II) is responsible for the production of messenger RNA (mRNA) within the cell. Particularly for Pol II, much of the regulatory checkpoints in the transcription process occur in the assembly and escape of the pre-initiation complex. A gene-specific combination of transcription factors will recruit TFIID and/or TFIIA to the core promoter, followed by the association of TFIIB, creating a stable complex onto which the rest of the General Transcription Factors (GTFs) can assemble. This complex is relatively stable, and can undergo multiple rounds of transcription initiation.
After the binding of TFIIB and TFIID, Pol II the rest of the GTFs can assemble. This assembly is marked by the post-translational modification (typically phosphorylation) of the C-terminal domain (CTD) of Pol II through a number of kinases. The CTD is a large, unstructured domain extending from the RbpI subunit of Pol II, and consists of many repeats of the heptad sequence YSPTSPS. TFIIH, the helicase that remains associated with Pol II throughout transcription, also contains a subunit with kinase activity which will phosphorylate the serines 5 in the heptad sequence. Similarly, both CDK8 (a subunit of the massive multiprotein Mediator complex) and CDK9 (a subunit of the p-TEFb elongation factor), have kinase activity towards other residues on the CTD. These phosphorylation events promote the transcription process and serve as sites of recruitment for mRNA processing machinery. All three of these kinases respond to upstream signals, and failure to phosphorylate the CTD can lead to a stalled polymerase at the promoter. | 1 | Gene expression + Signal Transduction |
The main distinguishing feature between p90 and p70 is that the 90 kDa family contain two non-identical kinase domains, while the 70 kDa family contain only one kinase domain. | 1 | Gene expression + Signal Transduction |
The eutectoid composition of austenite is approximately 0.8% carbon; steel with less carbon content (hypoeutectoid steel) will contain a corresponding proportion of relatively pure ferrite crystallites that do not participate in the eutectoid reaction and cannot transform into pearlite. Likewise steels with higher carbon content (hypereutectoid steels) will form cementite before reaching the eutectoid point. The proportion of ferrite and cementite forming above the eutectoid point can be calculated from the iron/iron—carbide equilibrium phase diagram using the lever rule.
Steels with pearlitic (eutectoid composition) or near-pearlitic microstructure (near-eutectoid composition) can be drawn into thin wires. Such wires, often bundled into ropes, are commercially used as piano wires, ropes for suspension bridges, and as steel cord for tire reinforcement. High degrees of wire drawing (logarithmic strain above 3) leads to pearlitic wires with yield strengths of several gigapascals. It makes pearlite one of the strongest structural bulk materials on earth.
Some hypereutectoid pearlitic steel wires, when cold wire drawn to true (logarithmic) strains above 5, can even show a maximal tensile strength above . Although pearlite is used in many engineering applications, the origin of its extreme strength is not well understood. It has been recently shown that cold wire drawing not only strengthens pearlite by refining the lamellae structure, but also simultaneously causes partial chemical decomposition of cementite, associated with an increased carbon content of the ferrite phase, deformation induced lattice defects in ferrite lamellae, and even a structural transition from crystalline to amorphous cementite. The deformation-induced decomposition and microstructural change of cementite is closely related to several other phenomena such as a strong redistribution of carbon and other alloy elements like silicon and manganese in both the cementite and the ferrite phase; a variation of the deformation accommodation at the phase interfaces due to a change in the carbon concentration gradient at the interfaces; and mechanical alloying.
Pearlite was first identified by Henry Clifton Sorby and initially named sorbite, however the similarity of microstructure to nacre and especially the optical effect caused by the scale of the structure made the alternative name more popular.
Bainite is a similar structure with lamellae much smaller than the wavelength of visible light and thus lacks this pearlescent appearance. It is prepared by more rapid cooling. Unlike pearlite, whose formation involves the diffusion of all atoms, bainite grows by a displacive transformation mechanism.
The transformation of pearlite to austenite takes place at lower critical temperature of . At this temperature pearlite changes to austenite because of nucleation process. | 0 | Metallurgy |
Dissimilar metals and alloys have different electrode potentials, and when two or more come into contact in an electrolyte, one metal (that is more reactive) acts as anode and the other (that is less reactive) as cathode. The electropotential difference between the reactions at the two electrodes is the driving force for an accelerated attack on the anode metal, which dissolves into the electrolyte. This leads to the metal at the anode corroding more quickly than it otherwise would and corrosion at the cathode being inhibited. The presence of an electrolyte and an electrical conducting path between the metals is essential for galvanic corrosion to occur. The electrolyte provides a means for ion migration whereby ions move to prevent charge build-up that would otherwise stop the reaction. If the electrolyte contains only metal ions that are not easily reduced (such as Na, Ca, K, Mg, or Zn), the cathode reaction is the reduction of dissolved H to H or O to OH.
In some cases, this type of reaction is intentionally encouraged. For example, low-cost household batteries typically contain carbon-zinc cells. As part of a closed circuit (the electron pathway), the zinc within the cell will corrode preferentially (the ion pathway) as an essential part of the battery producing electricity. Another example is the cathodic protection of buried or submerged structures as well as hot water storage tanks. In this case, sacrificial anodes work as part of a galvanic couple, promoting corrosion of the anode, while protecting the cathode metal.
In other cases, such as mixed metals in piping (for example, copper, cast iron and other cast metals), galvanic corrosion will contribute to accelerated corrosion of parts of the system. Corrosion inhibitors such as sodium nitrite or sodium molybdate can be injected into these systems to reduce the galvanic potential. However, the application of these corrosion inhibitors must be monitored closely. If the application of corrosion inhibitors increases the conductivity of the water within the system, the galvanic corrosion potential can be greatly increased.
Acidity or alkalinity (pH) is also a major consideration with regard to closed loop bimetallic circulating systems. Should the pH and corrosion inhibition doses be incorrect, galvanic corrosion will be accelerated. In most HVAC systems, the use of sacrificial anodes and cathodes is not an option, as they would need to be applied within the plumbing of the system and, over time, would corrode and release particles that could cause potential mechanical damage to circulating pumps, heat exchangers, etc. | 0 | Metallurgy |
The company was founded on June 15, 1917, with Spanish-French financial support, with a capital stock of 25 million pesetas. It was born in the context of a boom in Spanish industry, in the heat of the First World War. Two foreign capital companies were involved in its creation, the Sociedad Minera y Metalúrgica de Peñarroya (SMMP) and the Rio Tinto Company Limited (RTC), both of which became shareholders of the new company. The SECEM owned an important plant in Cordoba dedicated to copper metallurgy, brass production, manufacture of motors and electric transformers, etc. Over the years it ended up becoming one of the main companies in the sector, having also a great importance in the local context of Cordoba.
The company came to manufacture nearly 40% of all the electrolytic copper produced in Spain, being supplied to a large extent by the material coming from the Rio Tinto-Nerva mining basin. In this sense, SECEM became an important client of the Compañía Española de Minas de Río Tinto (CEMRT), and later the companies Río Tinto Patiño and Río Tinto Minera would have an important shareholding in SECEM. In spite of this privileged situation, the lack of internal competition meant that the machinery and technology of the Cordovan factory were not modernized, which in the long term would end up causing serious problems for SECEM's economic viability. Towards the end of the 1970s, the industrial crisis had a considerable impact on the copper sector. Taking advantage of this context, in May 1978 SECEM —with the financial support of Banco de Bilbao and Banco Hispano Americano— proceeded to acquire the companies Pradera Hermanos, Sociedad Industrial Asturiana and Earle; at the end of the year, all of these companies formed the conglomerate Ibercobre, which controlled 60% of the copper market.
The SECEM complex in Cordoba remained intact until 1989–1990, after the purchase of Ibercobre by the Finnish company Outokumpu, which decided to split it into three separate industries. | 0 | Metallurgy |