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* Killick, D. 2004. Review Essay: "What Do We Know About African Iron Working?" Journal of African Archaeology. Vol 2 (1) pp. 135–152
* Bocoum, H. (ed.), 2004, The origins of iron metallurgy in Africa – New lights on its antiquity, H. Bocoum (ed.), UNESCO publishing
* Schmidt, P.R., Mapunda, B.B., 1996. "Ideology and the Archaeological Record in Africa: Interpreting Symbolism in Iron Smelting Technology". Journal of Anthropological Archaeology. Vol 16, pp. 73–102
* Rehren, T., Charlton, M., Shadrek, C., Humphris, J., Ige, A., Veldhuijen, H.A. "Decisions set in slag: the human factor in African iron smelting". La Niece, S., Hook, D., and Craddock, P., (eds). Metals and mines : studies in archaeometallurgy. 2007, pp. 211–218.
* Okafor, E.E., 1993. "New Evidence on Early Iron-Smelting from Southeastern Nigeria". Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp. 432–448
* Kense, F.J., and Okora, J.A., 1993. "Changing Perspectives on Traditional Iron Production in West Africa". Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp. 449– 458
* Muhammed, I.M., 1993. "Iron Technology in the Middle Sahel/Savanna: With Emphasis on Central Darfur". Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp. 459–467
* Buleli, NS., 1993. Iron-Making Techniques in the Kivu Region of Zaire: Some of the Differences Between the South Maniema Region and North Kivu. Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns'. London, Routledge, pp. 468–477
* Radimilahy, C., 1993 "Ancient Iron-Working in Madagascar". Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp. 478–473
* Kiriama, H.O., 1993. "The Iron Using Communities in Kenya". Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp. 484–498
* Martinelli, B., 1993, "Fonderies ouest-africaines. Classement comparatif et tendances", in Atouts et outils de lethnologie des techniques – Sens et tendance en technologie comparée, Revue Techniques et culture', n 21 : 195–221.
* Martinelli, B., 2004, "On the Threshold of Intensive Metallurgy – The choice of Slow Combustion in the Niger River Bend (Burkina Faso and Mali)" in The origins of iron metallurgy in Africa – New lights on its antiquity, H. Bocoum (ed.), UNESCO publishing : pp. 216–247
* Collet, D.P., 1993. "Metaphors and Representations Associated with Precolonial Iron-Smelting in Eastern and Southern Africa". Shaw, T., Sinclair, P., Bassey, A., Okpoko, A (eds). The Archaeology of Africa Food, Metals and Towns. London, Routledge, pp. 499–511 | 0 | Metallurgy |
Non-coding DNA (ncDNA) sequences are components of an organism's DNA that do not encode protein sequences. Some non-coding DNA is transcribed into functional non-coding RNA molecules (e.g. transfer RNA, microRNA, piRNA, ribosomal RNA, and regulatory RNAs). Other functional regions of the non-coding DNA fraction include regulatory sequences that control gene expression; scaffold attachment regions; origins of DNA replication; centromeres; and telomeres. Some non-coding regions appear to be mostly nonfunctional, such as introns, pseudogenes, intergenic DNA, and fragments of transposons and viruses. Regions that are completely nonfunctional are called junk DNA. | 1 | Gene expression + Signal Transduction |
: The codon AUG both codes for methionine and serves as an initiation site: the first AUG in an mRNA's coding region is where translation into protein begins. | 1 | Gene expression + Signal Transduction |
Detonation spraying is one of the many forms of thermal spraying techniques that are used to apply a protective coating at supersonic velocities to a material in order to change its surface characteristics. This is primarily to improve the durability of a component. It was first invented in 1955 by H.B. Sargent, R.M. Poorman and H. Lamprey and is applied to a component using a specifically designed detonation gun (D-gun). The component being sprayed must be prepared correctly by removing all surface oils, greases, debris and roughing up the surface in order to achieve a strongly bonded detonation spray coating. This process involves the highest velocities (≈3500 m/s shockwave that propels the coating materials) and temperatures (≈4000 °C) of coating materials compared to all other forms of thermal spraying techniques. Which means detonation spraying is able to apply low porous (below 1%) and low oxygen content (between 0.1 and 0.5%) protective coatings that protect against corrosion, abrasion and adhesion under low load.
This process allows the application of very hard and dense surface coatings which are useful as wear resistant coatings. For this reason, detonation spraying is commonly used for protective coatings in aircraft engines, plug and ring gauges, cutting edges (skiving knives), tubular drills, rotor and stator blades, guide rails or any other metallic material that is subject to high wear and tear. Commonly the materials that are sprayed onto components during detonation spraying are powders of metals, metal alloys and cermets; as well as their oxides (aluminum, copper, iron, etc.).
Detonation spraying is an industrial process that can be dangerous if not performed correctly and in a safe environment. As such there are many safety precautions that must be adhered to when using this thermal spraying technique. | 0 | Metallurgy |
Bauxite ore is a mixture of hydrated aluminium oxides and compounds of other elements such as iron. The aluminium compounds in the bauxite may be present as gibbsite (Al(OH)), böhmite (γ-AlO(OH)) or diaspore (α-AlO(OH)); the different forms of the aluminium component and the impurities dictate the extraction conditions. Aluminium oxides and hydroxides are amphoteric, meaning that they are both acidic and basic. The solubility of Al(III) in water is very low but increases substantially at either high or low pH. In the Bayer process, bauxite ore is heated in a pressure vessel along with a sodium hydroxide solution (caustic soda) at a temperature of 150 to 200 °C. At these temperatures, the aluminium is dissolved as sodium aluminate (primarily [Al(OH)]) in an extraction process. After separation of the residue by filtering, gibbsite is precipitated when the liquid is cooled and then seeded with fine-grained aluminium hydroxide crystals from previous extractions. The precipitation may take several days without addition of seed crystals.
The extraction process (digestion) converts the aluminium oxide in the ore to soluble sodium aluminate, NaAlO, according to the chemical equation:
:AlO + 2 NaOH → 2 NaAlO + HO
This treatment also dissolves silica, forming sodium silicate :
:2 NaOH + SiO → NaSiO + HO
The other components of Bauxite, however, do not dissolve. Sometimes lime is added at this stage to precipitate the silica as calcium silicate. The solution is clarified by filtering off the solid impurities, commonly with a rotary sand trap and with the aid of a flocculant such as starch, to remove the fine particles. The undissolved waste after the aluminium compounds are extracted, bauxite tailings, contains iron oxides, silica, calcia, titania and some unreacted alumina. The original process was that the alkaline solution was cooled and treated by bubbling carbon dioxide through it, a method by which aluminium hydroxide precipitates:
:2 NaAlO + 3 HO + CO → 2 Al(OH) + NaCO
But later, this gave way to seeding the supersaturated solution with high-purity aluminium hydroxide (Al(OH)) crystal, which eliminated the need for cooling the liquid and was more economically feasible:
:2 HO + NaAlO → Al(OH) + NaOH
Some of the aluminium hydroxide produced is used in the manufacture of water treatment chemicals such as aluminium sulfate, PAC (Polyaluminium chloride) or sodium aluminate; a significant amount is also used as a filler in rubber and plastics as a fire retardant. Some 90% of the gibbsite produced is converted into aluminium oxide, AlO, by heating in rotary kilns or fluid flash calciners to a temperature of about 1470 K.
:2 Al(OH) → AlO + 3 HO
The left-over, spent sodium aluminate solution is then recycled. Apart from improving the economy of the process, recycling accumulates gallium and vanadium impurities in the liquors, so that they can be extracted profitably.
Organic impurities that accumulate during the precipitation of gibbsite may cause various problems, for example high levels of undesirable materials in the gibbsite, discoloration of the liquor and of the gibbsite, losses of the caustic material, and increased viscosity and density of the working fluid.
For bauxites having more than 10% silica, the Bayer process becomes uneconomic because of the formation of insoluble sodium aluminium silicate, which reduces yield, so another process must be chosen.
1.9-3.6 tons of bauxite (corresponding to about 90% of the alumina content of the bauxite) is required to produce 1 ton of aluminium oxide. This is due to a majority of the aluminium in the ore being dissolved in the process. Energy consumption is between 7 GJ/tonne to 21 GJ/tonne (depending on process), of which most is thermal energy. Over 90% (95-96%) of the aluminium oxide produced is used in the Hall–Héroult process to produce aluminium. | 0 | Metallurgy |
Bases: adenine (A), cytosine (C), guanine (G) and thymine (T) or uracil (U).
Amino acids: Alanine (Ala, A), Arginine (Arg, R), Asparagine (Asn, N), Aspartic acid (Asp, D), Cysteine (Cys, C), Glutamic acid (Glu, E), Glutamine (Gln, Q), Glycine (Gly, G), Histidine (His, H), Isoleucine (Ile, I), Leucine (Leu, L), Lysine (Lys, K), Methionine (Met, M), Phenylalanine (Phe, F), Proline (Pro, P), Serine (Ser, S), Threonine (Thr, T), Tryptophan (Trp, W), Tyrosine (Tyr, Y), and Valine (Val, V). | 1 | Gene expression + Signal Transduction |
By the late Uruk period development had grown to include a large temple/palace complex.
Culturally, Melid was part of the "Northern regions of Greater Mesopotamia" functioning as a trade colony along the Euphrates River bringing raw materials to Sumer (Lower Mesopotamia).
Numerous similarities have been found between these early layers at Arslantepe, and the somewhat later site of Birecik (Birecik Dam Cemetery), also in Turkey, to the southwest of Melid.
Around 3000 BCE, the transitional EBI-EBII, there was widespread burning and destruction, after which Kura–Araxes pottery appeared in the area. This was a mainly pastoralist culture connected with the Caucasus mountains. | 0 | Metallurgy |
Similar to copper oxide heap leaching, also using dilute sulfuric acid. Rio Tinto is commercializing this technology in Namibia and Australia; the French nuclear fuel company Orano, in Niger with two mines and Namibia; and several other companies are studying its feasibility.
The final product is yellowcake and requires significant further processing to produce fuel-grade feed. | 0 | Metallurgy |
Smiths contributions to engineering education encompass work in cooperative learning and knowledge engineering applications. He published a paper in the Journal of Engineering Education', in 1981, introducing cooperative learning in engineering literature. During the early 1980s, he conducted some of the first randomized design empirical studies on cooperative learning in engineering classes. Subsequently, in the late 1980s, he transitioned from engineering research to education research, particularly focusing on cooperative learning and structured controversy, as his emphasis shifted towards teaching and research on project and knowledge management. This research addressed the critical needs of enhancing student learning, deepening understanding, and fostering collaborative skills. Beyond cooperative learning, his work included structured academic controversy, aimed at facilitating comprehensive understanding of complex issues through argument development and cooperative learning strategies.
Smith published books on this topic, including Active Learning: Cooperation in the College Classroom with David W. Johnson and Roger T. Johnson, providing strategies for college faculty to implement cooperative learning. They also co-authored Cooperative learning: Increasing College Faculty Instructional Productivity, in which they delved into the basics of cooperative learning, and he discussed how cooperative learning changed college teaching in New Paradigms for College Teaching that he co-edited with William E. Campbell. Later, in 2000, he wrote Teamwork and Project Management, where he emphasized key skills for engineering success, including teamwork, problem-solving, and project management. | 0 | Metallurgy |
The green patina that forms naturally on copper and bronze, sometimes called verdigris, usually consists of varying mixtures of copper chlorides, sulfides, sulfates, and carbonates, depending upon environmental conditions such as sulfur-containing acid rain. In clean air rural environments, the patina is created by the slow chemical reaction of copper with carbon dioxide and water, producing a basic copper carbonate. In industrial and urban air environments containing sulfurous acid rain from coal-fired power plants or industrial processes, the final patina is primarily composed of sulphide or sulphate compounds.
A patina layer takes many years to develop under natural weathering. Buildings in damp coastal or marine environments will develop patina layers faster than ones in dry inland areas.
Façade cladding (copper cladding; copper wall cladding) with alloys of copper, like brass or bronze, will weather differently from "pure" copper cladding. Even a lasting gold colour is possible with copper-alloy cladding, for example Bristol Beacon in Bristol, or the Novotel at Paddington Central, London.
Antique and well-used firearms will often develop a layer of rust on the action, barrel, or other steel parts after the original finish has worn. On this subject gunsmith Mark Novak says "... This is what everybody calls patina, I call it a nice thick coat of rust..." The removal of such rust is often necessary for a firearm conservation to prevent further decay of the firearm. | 0 | Metallurgy |
Due to the relatively small sample size achievable with dealloying, the mechanical properties of these materials are often probed using the following techniques:
* Nanoindentation
* Micropillar compression
* Deflection testing of bridges
* Thin-film wrinkling | 0 | Metallurgy |
Particular disadvantages of the powder technology include:
# 100% sintered (iron ore) cannot be charged in the blast furnace
# sintering cannot create uniform sizes
# micro- and nanostructures produced before sintering are often destroyed. | 0 | Metallurgy |
Two proteins are crucial for interacting ethylene with the receptors, namely constitutive triple response 1 (CTR1) and ethylene insensitive 2 (EIN2). CTR1 is a serine/threonine protein kinase that functions as a negative regulator of ethylene signalling. It is a member of the signaling protein mitogen-activated protein kinase (MAPK) kinase kinase. EIN2 is required for ethylene signalling and is part of the NRAMP (natural resistance-associated macrophage protein) family of metal transporters; it comprises a large, N-terminal portion containing multiple transmembrane domains (EIN2-N) in the ER membrane and a cytosolic C-terminal portion (EIN2-C). Other proteins such as reversion to ethylene sensitivity 1 (RTE1), cytochrome b5 and tetratricopeptide repeat protein 1 (TRP1) also play important roles in ethylene signaling. RTE1 is a highly conserved proteins in plants and protists but absent in fungi and prokaryotes. TRP1 is genetically related to transmembrane and coiled-coil protein 1 (TCC1) in animals that is involved F actin function and competes with Raf-1 for Ras binding.
Unlike in most signal transductions where the ligands activate their receptors to relay their signals, ethylene acts as the suppressor of its receptor, and the receptor being the negative regulator in ethylene responses. Ethylene receptor is active in the absence of ethylene. Without ethylene, the receptor binds to CTR1 at its C-terminal kinase domain. The kinase activity of CTR1 becomes activated and phosphorylates the neighbouring EIN2. As long as EIN2 remains highly phosphorylated, it remains inactive and there never is an ethylene signal relay. In ETR1, the receptor histidine kinase is required for binding with EIN2. RTE1 can bind to and activate ETR1 independent of CTR1. There is evidence that cytochrome b5 aids or acts similar to RTE1.
Ethylene binding to the receptor disrupts the EIN2 phosphorylation. It does not cause any particular change in the structural feature of the receptor-CTR1-EIN2 complex or stop the phosphorylation. In fact, at low level of ethylene there is increased receptor-CTR1-EIN2 complexes, which is then reduced as ethylene level rises. The turnover process is not yet fully understood. The only consequence of ethylene binding is reduced phosphorylation of EIN2. Under such condition EIN2 is activated and is cleaved to release EIN2-C from the membrane-bound EIN2-N portion. The enzyme that causes the cleavage is yet unknown. The role of EIN2-N is also unknown in A. thaliana. But in rice, its homologue OsEIN2-N (Os for Oryza sativa, the scientific name for rice) interacts with another protein, mao huzi 3 (MHZ3), a mutation of which gives rise to insensitivity to ethylene.
EIN2-C is the main component that mediates ethylene signal in the cell. It acts in two ways. In one, it binds the mRNAs that encode for EIN3-binding F-box proteins, EBF1 and EBF2 to cause their degradation. In another, it enters the nucleus to bind with EIN2 nuclear associated protein 1 (ENAP1) to regulate transcriptional and translational activities of EIN3 and the related EIL1 transcription factor to cause most of the ethylene responses. | 1 | Gene expression + Signal Transduction |
Fionn Patrick Edward Dunne is a Professor of Materials Science at Imperial College London and holds the Chair in Micromechanics and the Royal Academy of Engineering/Rolls-Royce Research Chair. Professor Dunne specialises in computational crystal plasticity and microstructure-sensitive nucleation and growth of short fatigue cracks in engineering materials, mainly Nickel, Titanium and Zirconium alloys. | 0 | Metallurgy |
Nikolai Timofeevich Beliaev or Nicholas Timothy Belaiew (26 June 1878 – 5 November 1955) was a Russian metallurgist. He was famous for his studies on Damascus steel and the idea of crystallization in metals and the production of Widmanstatten structures. He also wrote on the history of steel making.
Beliaev was born in St. Petersburg to General T. M. Beliaev and Maria Nikolayevna Septjurina. He was educated at Mikhailovskaya Artilleriiskaya Academy and was trained under Dmitry Konstantinovich Chernov and Henry Le Chatelier. He became a professor of metallurgy in 1909. During World War I he was wounded and he was sent to England in 1915. He received a Bessemer Gold Medal in 1937 from the British Institute of Steel and Iron in London. A major contribution was on the studies of crystal structure in steels both man-made and of meteoric origin and examined their mechanical properties. He also took an interest in Icelandic research. | 0 | Metallurgy |
Chemokines are functionally divided into two groups:
*Homeostatic: are constitutively produced in certain tissues and are responsible for basal leukocyte migration. These include: CCL14, CCL19, CCL20, CCL21, CCL25, CCL27, CXCL12 and CXCL13. This classification is not strict; for example, CCL20 can act also as pro-inflammatory chemokine.
*Inflammatory: these are formed under pathological conditions (on pro-inflammatory stimuli, such as IL-1, TNF-alpha, LPS, or viruses) and actively participate in the inflammatory response attracting immune cells to the site of inflammation. Examples are: CXCL-8, CCL2, CCL3, CCL4, CCL5, CCL11, CXCL10. | 1 | Gene expression + Signal Transduction |
Within computational biology, an MA plot is an application of a Bland–Altman plot for visual representation of genomic data. The plot visualizes the differences between measurements taken in two samples, by transforming the data onto M (log ratio) and A (mean average) scales, then plotting these values. Though originally applied in the context of two channel DNA microarray gene expression data, MA plots are also used to visualise high-throughput sequencing analysis. | 1 | Gene expression + Signal Transduction |
This is an example of a DNA microarray experiment which includes details for a particular case to better explain DNA microarray experiments, while listing modifications for RNA or other alternative experiments.
# The two samples to be compared (pairwise comparison) are grown/acquired. In this example treated sample (case) and untreated sample (control).
# The nucleic acid of interest is purified: this can be RNA for expression profiling, DNA for comparative hybridization, or DNA/RNA bound to a particular protein which is immunoprecipitated (ChIP-on-chip) for epigenetic or regulation studies. In this example total RNA is isolated (both nuclear and cytoplasmic) by Guanidinium thiocyanate-phenol-chloroform extraction (e.g. Trizol) which isolates most RNA (whereas column methods have a cut off of 200 nucleotides) and if done correctly has a better purity.
# The purified RNA is analysed for quality (by capillary electrophoresis) and quantity (for example, by using a NanoDrop or NanoPhotometer spectrometer). If the material is of acceptable quality and sufficient quantity is present (e.g., >1μg, although the required amount varies by microarray platform), the experiment can proceed.
# The labeled product is generated via reverse transcription and followed by an optional PCR amplification. The RNA is reverse transcribed with either polyT primers (which amplify only mRNA) or random primers (which amplify all RNA, most of which is rRNA). miRNA microarrays ligate an oligonucleotide to the purified small RNA (isolated with a fractionator), which is then reverse transcribed and amplified.
#* The label is added either during the reverse transcription step, or following amplification if it is performed. The sense labeling is dependent on the microarray; e.g. if the label is added with the RT mix, the cDNA is antisense and the microarray probe is sense, except in the case of negative controls.
#* The label is typically fluorescent; only one machine uses radiolabels.
#* The labeling can be direct (not used) or indirect (requires a coupling stage). For two-channel arrays, the coupling stage occurs before hybridization, using aminoallyl uridine triphosphate (aminoallyl-UTP, or aaUTP) and NHS amino-reactive dyes (such as cyanine dyes); for single-channel arrays, the coupling stage occurs after hybridization, using biotin and labeled streptavidin. The modified nucleotides (usually in a ratio of 1 aaUTP: 4 TTP (thymidine triphosphate)) are added enzymatically in a low ratio to normal nucleotides, typically resulting in 1 every 60 bases. The aaDNA is then purified with a column (using a phosphate buffer solution, as Tris contains amine groups). The aminoallyl group is an amine group on a long linker attached to the nucleobase, which reacts with a reactive dye.
#** A form of replicate known as a dye flip can be performed to control for dye artifacts in two-channel experiments; for a dye flip, a second slide is used, with the labels swapped (the sample that was labeled with Cy3 in the first slide is labeled with Cy5, and vice versa). In this example, aminoallyl-UTP is present in the reverse-transcribed mixture.
# The labeled samples are then mixed with a proprietary hybridization solution which can consist of SDS, SSC, dextran sulfate, a blocking agent (such as Cot-1 DNA, salmon sperm DNA, calf thymus DNA, PolyA, or PolyT), Denhardt's solution, or formamine.
# The mixture is denatured and added to the pinholes of the microarray. The holes are sealed and the microarray hybridized, either in a hyb oven, where the microarray is mixed by rotation, or in a mixer, where the microarray is mixed by alternating pressure at the pinholes.
# After an overnight hybridization, all nonspecific binding is washed off (SDS and SSC).
# The microarray is dried and scanned by a machine that uses a laser to excite the dye and measures the emission levels with a detector.
# The image is gridded with a template and the intensities of each feature (composed of several pixels) is quantified.
# The raw data is normalized; the simplest normalization method is to subtract background intensity and scale so that the total intensities of the features of the two channels are equal, or to use the intensity of a reference gene to calculate the t-value for all of the intensities. More sophisticated methods include z-ratio, loess and lowess regression and RMA (robust multichip analysis) for Affymetrix chips (single-channel, silicon chip, in situ synthesized short oligonucleotides). | 1 | Gene expression + Signal Transduction |
The lac repressor was first isolated by Walter Gilbert and Benno Müller-Hill in 1966. They showed that in vitro the protein bound to DNA containing the lac operon, and it released the DNA when IPTG (an analog of allolactose) was added. | 1 | Gene expression + Signal Transduction |
Although the Pidgeon process has many perks, there are some environmental disadvantages of the process as well. Since increased demand for magnesium has risen in recent years, production through ore reduction has been emitting large amounts of carbon dioxide and particulate matter. Due to the lightweight nature of magnesium as well as its high energy density, suggestions have been made about the global consumption of this versatile metal drastically increasing even more than it already has. There are environmental impacts because to create light weight materials in the first place, more energy is needed compared to the material being replaced, typically iron or steel. As an approximate, around 10.4 kg of coal is burned and 37 kg of carbon dioxide is released, per 1 kg of magnesium obtained. In China, production of magnesium using the Pidgeon process has a 60% higher global warming impact than aluminum, a competing metal mass produced in the country as well. Ultimately, more information and research is needed to make new energy saving changes to reduce the environmental impact of magnesium production on a global scale. | 0 | Metallurgy |
The location of spliceosomal activity for the minor class spliceosome is regarded by most experts to be in the nucleus. However, a single paper has claimed that the minor spliceosome is active in the cytosol. The data presented within this paper are not fully accepted within the field and directly contradict numerous other papers. | 1 | Gene expression + Signal Transduction |
Biohydrometallurgy is a technique in the world of metallurgy that utilizes biological agents (bacteria) to recover and treat metals such as copper. Modern biohydrometallurgy advances started with the bioleaching of copper more efficiently in the 1950's | 0 | Metallurgy |
The Pedersen Process was invented by Harald Pedersen in the 1920s and used in Norway for over 40 years before shutting down due to the Pedersen Process being less economically competitive than the Bayer Process. However, it is believed a modern Pedersen process could be economically viable with "low-quality" bauxite, as even though "low-quality" bauxite has less alumina in the form of trihydrate gibbsite, it has more iron oxide which would be converted to pig iron in the smelting process instead of red mud. | 0 | Metallurgy |
The modernization of private and state-owned factories and the construction of railways, which began in the 1910s, were not completed by the beginning of the war. Thinking the war would be brief, the government did not involve the private factories of the Urals in the production of guns and shells until the summer of 1915. As a result, the Ural industry was late in getting involved in providing the army with weapons and equipment. In 1914-1916, state-owned factories maintained the pre-war production of iron, but completely stopped the production of roofing iron in favor of military products. The production of high-grade iron and projectile steel was almost doubled. The sharp increase in production volumes was hindered by the lack of fuel resources, labor, and means for transporting goods. In 1915-1916, due to the lack of fuel in the Urals, 22 blast furnaces were stopped, and 11 furnaces worked at a reduced capacity. The situation was aggravated by the disorganization of railway transportation due to the priority of military needs and the mobilization of qualified personnel. In the summer of 1915, a commission headed by General A. A. Manikovsky was sent to the Urals to negotiate with private factory owners and explore the possibility of private factories participating in the production of military products, and to coordinate the actions of private factories. On November 7, 1915, the Ural Factory Meeting was established under the leadership of the Chief Head of the Ural Mining Department, P. I. Yegorov. In the future, it became obvious that the created administrative apparatus could not fulfill the tasks assigned to it. The difficult situation at the front in 1915 and the acute shortage of weapons forced the government to accept the inflated demands of entrepreneurs. As a result of negotiations, military orders were accepted by private factory owners at increased prices. The total cost of the orders was estimated at 200 million rubles.
The position of the working people worsened during the war years. The working day increased to 12 hours, women and children worked on an equal basis with men, but they were paid half as much. The organization of production was unsatisfactory: the factories received orders that they could not fulfill due to the lack of necessary equipment. After the defeat of the Russian troops in 1915-1916, 87% of the Ural factories switched to the production of military products. With the support of the authorities, commercial companies with the participation of foreign capital developed. In 1915-1918, large machine-building plants were evacuated from the front-line territories of the Baltics and Petrograd, to the Urals. The staff of the arms factories was replenished with evacuated specialists.
After the February Revolution, power passed into the hands of provincial commissars appointed by the Provisional Government. Ural miners supported the Provisional Government and its bodies. On March 4, 1917, the Council of Miners Congresses asked the government to appoint a commissar to control the work of the Ural factories. Such a commissar was appointed, businessman V. I. Europeus, who headed the created Provisional Committee of the Ural Mining District. At some factories (Nyazepetrovsky, Sosvensky, Bilimbaevsky, Zlatoustovsky, Nizhne-Ufaleysky), before the October Revolution, power was partially or completely seized by the Soviets of Workers Deputies. The state of production continued to deteriorate, there was a critical shortage of fuel, railroad transportation became practically unmanageable, enterprises worked with interruptions, equipment was not repaired or updated in a timely manner. Smelting of pig iron and steel declined rapidly, and the number of industrial accidents increased. The commission sent by the Provisional Government in 1917 to restore the working capacity of the Ural enterprises failed to manage the task.
After the October Revolution, in November 1917, the Ural Factory Meeting was reorganized under the leadership of the Bolsheviks. Its powers were extended by the decree of the Supreme Economic Council of the Republic to the Vyatka, Orenburg, Perm and Ufa provinces, and a number of adjacent districts. The Ural Mining Board and the Yekaterinburg Bureau of the Council of the Congress of Mining Industrialists of the Urals were liquidated. In November - December 1917, the boards of Ural joint-stock companies suspended the transfer of money to factories where Soviet control was introduced, which led to delays in the payment of wages and the accumulation of debts for the supply of raw materials and food. There were pockets of famine and epidemics of diseases, the situation of workers-prisoners of war was especially difficult. In December 1917, the Council of People's Commissars began the nationalization of the mountain districts of the Urals, earlier than other enterprises of the country. By July 1918, more than 4,340 enterprises (25 out of 34 mountain districts of the Urals) had been nationalized. In 1918, in addition to the factory committees established earlier, business councils were established to manage the factories, whose activities were coordinated by the regional board of the nationalized enterprises of the Urals. Such actions led to a certain dual power in the management of enterprises in the industry, and since March 1918, factory committees have been merged with trade unions. Since 1918, systematic training of engineers and workers for the metallurgical industry began in educational institutions of the Urals.
Due to supply disruptions and salary delays in the summer and autumn of 1918, anti-Soviet demonstrations took place at the Ural factories. By July 1918, out of 89 Ural blast furnaces, 51 were in operation, and 59 of 88 open-hearth furnaces were in operation. In August, Soviet power was overthrown in Izhevsk and Votkinsk. At the same time, the Regional Government of the Urals was formed in Yekaterinburg, the Ural Industrial Committee was created to manage the industry, the Main Directorate of Mining Affairs of the Urals was established to manage the mining industry, which was transformed in December into the Ural Mining Administration. On August 19, the Provisional Regional Government of the Urals, in its declaration, announced its intention to return the factories to their previous owners. By December 10, 1918, only 36 mining and 9 small and medium-sized coal enterprises in the Urals and Siberia were denationalized. All these changes had practically no effect on the real state of the Ural industry. The plans of the Kolchak government to subsidize the Ural factories also did not come true. The situation was aggravated by the complete dependence of the inhabitants of the factory settlements on the work of enterprises and the political struggle of the provisional governments. In late 1918 - early 1919, the enterprises of Verkh-Isetsky, Revdinsky, Shaitansky, Zlatoustovsky, and a number of other districts were stopped.
After the restoration of Soviet power in the Urals in mid-1919, the management of the factories was centralized under the auspices of the Supreme Council of the National Economy. Later, the Ural Industrial Bureau of the Supreme Economic Council was created. The debts of the enterprises were canceled, a free supply of raw materials and materials was established, finished products were also handed over without payment according to centralized orders. By the end of 1919, 14 blast furnaces, 16 open-hearth furnaces, and 49 rolling mills were operating at the Ural factories. To manage the factories, five regional departments were created: Vysokogorskoe (18 enterprises), Bogoslovskoe (5 enterprises), Yekaterinburg (31 enterprises), Permskoe (17 enterprises), and Yuzhno-Uralskoe (20 enterprises). In 1920, the re-evacuation of workers and specialists from Siberia began, as well as the return of the factory equipment taken out by the White Guards. On the whole, in 1919-1920, only 20% of the metallurgical plants of the Urals operated, and the volume of production was about 10% of the pre-war level. Of the 7 blast furnaces of the Nadezhdinsky Plant, the largest at that time, only one operated; the plants of the Goroblagodatsky Mining District were completely stopped. In total, in the Urals in December 1920, only 9 blast furnaces, 10 open-hearth furnaces, and about a dozen rail, pipe-rolling, and sheet mills were operating, which were completely shut down by August 1921. During the years of the Civil War, the equipment of enterprises was significantly damaged. The smelting of iron in 1921 amounted to 69 thousand tons, which was 7.5% of the pre-war level. | 0 | Metallurgy |
In the 1740s, Benjamin Huntsman found a means of melting blister steel, made by the cementation process, in crucibles. The resulting crucible steel, usually cast in ingots, was more homogeneous than blister steel. | 0 | Metallurgy |
Thermal spraying techniques are another popular finishing option, and often have better high temperature properties than electroplated coatings. Thermal spraying, also known as a spray welding process, is an industrial coating process that consists of a heat source (flame or other) and a coating material that can be in a powder or wire form, which is melted then sprayed on the surface of the material being treated at a high velocity. The spray treating process is known by many different names such as HVOF (High Velocity Oxygen Fuel), plasma spray, flame spray, arc spray and metalizing. | 0 | Metallurgy |
The first transcriptome studies were based on microarray techniques (also known as DNA chips). Microarrays consist of thin glass layers with spots on which oligonucleotides, known as "probes" are arrayed; each spot contains a known DNA sequence.
When performing microarray analyses, mRNA is collected from a control and an experimental sample, the latter usually representative of a disease. The RNA of interest is converted to cDNA to increase its stability and marked with fluorophores of two colors, usually green and red, for the two groups. The cDNA is spread onto the surface of the microarray where it hybridizes with oligonucleotides on the chip and a laser is used to scan. The fluorescence intensity on each spot of the microarray corresponds to the level of gene expression and based on the color of the fluorophores selected, it can be determined which of the samples exhibits higher levels of the mRNA of interest.
One microarray usually contains enough oligonucleotides to represent all known genes; however, data obtained using microarrays does not provide information about unknown genes. During the 2010s, microarrays were almost completely replaced by next-generation techniques that are based on DNA sequencing. | 1 | Gene expression + Signal Transduction |
The British Non-Ferrous Metals Research Association was a research group in the United Kingdom during the 20th century, bringing together public and privately funded research into metallurgy. The name was abbreviated officially to B.N.F.M.R.A. (the organisation was normally known as ‘The BNF’ during its life). It was formed in 1920 by members of the British Non-Ferrous Metals Federation which represented the commercial interests of British manufacturers of coppers and copper alloys, lead, zinc and other non-ferrous metals and their alloys, latterly including titanium. Robert Hutton was appointed director in 1921. | 0 | Metallurgy |
Traditionally bun ingots were seen as a primary product of smelting, forming at the base of a furnace beneath a layer of less dense slag. However, experimental reconstruction of copper smelting showed that regular plano-convex ingots are difficult to form within the smelting furnace, producing only small ingots or copper prills that need to be remelted. High purity copper bun ingots found in Late Bronze Age Britain and the Mediterranean seem to have undergone a secondary refining procedure.
The metallographic structure and high iron compositions of some plano-convex ingots suggest that they are the product of primary smelting. Tylecote suggested that Roman plano-convex copper ingots may have been formed by tapping both slag and copper in one step into a mould or pit outside the furnace. A similar process was described by Agricola in book IX of his De Re Metallica and has been replicated experimentally. | 0 | Metallurgy |
The Miller process is an industrial-scale chemical procedure used to refine gold to a high degree of purity (99.5%). It was patented by Francis Bowyer Miller in 1867. This chemical process involves blowing chlorine gas through molten, but (slightly) impure, gold. Nearly all metal contaminants react to form chlorides but gold does not at these high temperatures. The other metals volatilize or form a low density slag on top of the molten gold.
When all impurities have been removed from the gold (observable by a change in flame color) the gold is removed and processed in the manner required for sale or use. The resulting gold is 99.5% pure, but of lower purity than gold produced by the other common refining method, the Wohlwill process, which produces gold of up to 99.999% purity.
The Wohlwill process is commonly used for producing high-purity gold, such as in electronics work, where exacting standards of purity are required. When highest purity gold is not required, refiners use the Miller process due to its relative ease, quicker turnaround times, and because it does not tie up the large amount of gold in the form of chloroauric acid which the Wohlwill process permanently requires for the electrolyte. | 0 | Metallurgy |
M2DS was first described in 1999.
In a Nature article published on November 25, 2015, it was revealed that researchers at the Baylor College of Medicine, led by Dr. Huda Y. Zoghbi, have reversed MECP2 Duplication Syndrome in adult symptomatic mice using antisense therapy. Mice treated with an experimental ASO administered through the central nervous system had a reduction of MECP2 protein to normal levels and symptoms of hypoactivity, anxiety, and abnormal social behavior were resolved. Additionally, the seizure activity of the mice and abnormal EEG discharges were abolished. Initial studies demonstrated that reducing the MECP2 protein levels to the correct amount also normalized the expression of the other genes controlled by the MECP2 protein. | 1 | Gene expression + Signal Transduction |
The original Trail smelter for the nearby Rossland mines, was founded by the American mining engineer F. Augustus Heinze (1869 – 1914) who had already built a smelter in Butte, Montana. In 1896, Heinze initially incorporated his smelting and mining company in the United States and then in Canada. Within a period of 4 years, Heinze owned the "smelter, mining interests, railway lines, railway charters, and associated land grants." Walter Hull Aldridge (b. 1867), an American mining and metallurgical engineer, took a position with the president of the Canadian Pacific Railroad (CPR), Sir William Van Horne, to negotiate a deal with Heinze. Under Aldridges direction, the CPRs mining interests were incorporated under the name of the Consolidated Mining & Smelting Company, then known as the Consolidated or CM&S. At that time, Consolidated "controlled many of British Columbia's largest lead, silver, gold and copper mines, as well as the large reduction works at Trail."
In 1910, CM&S anticipated the decline of its Rossland mines and purchased the lead-zinc ore-rich Sullivan Mine. At that time, it was difficult to smelt ore from the Sullivan mine because of the presence of iron sulphide. A metallurgist from Ontario, Randolphe Ralph William Diamond who was hired by Consolidated, developed the process known as differential flotation that separated minerals by letting them "float" by "sticking to bubbles formed in certain mixtures of chemicals and oils". This ground-breaking technology increased production at the Sullivan Mine making it profitable for decades. It required a "long-term stable workforce" not just itinerant workers; mining towns grew around the mines and smelter. While 1924, was a peak year in terms of production, by 1927, sulphur dioxide (SO2) emissions from the smelter had contaminated the vegetation and the land the Columbia River valley in Washington State. Damages were estimated at $350,000 by the International Joint Commission in 1927.
In 1934, Cominco had initiated heavy water research at the smelter but it did not gain momentum until the outbreak of World War II. During the war, the Allies cooperated in researching nuclear fission with the goal of developing an atomic bomb. New research had revealed that heavy water could slow down the uranium neutron, making a chain reaction possible. Under the tenure of Selwyn G. Blaylock as Comincos president, the smelter was upgraded as part of the Manhattan Projects heavy water production program, under code name the P-9 Project. Princeton University physicist Hugh S. Taylor, who was in charge of United States Office of Scientific Research and Development (OSRD) research on heavy water research, gave Cominco $20,000 towards the upgrade modifications. Cominco produced heavy water for the United States from 1942 until 1956.
In the 1950s, a hydroelectric dam—the Waneta Dam—was built south of Trail on the Pend D’Oreille River, which provided inexpensive electricity to the smelter.
For decades the smelter provided well-paying employment for people who had only a high school education. Intergenerational families worked at the smelter and the company became Trail's "economic and cultural centre."
In the spring of 2017, Teck Resources announced that they were considering a CA$1.2-billion deal to sell its Waneta Dam to BC Hydro. At the time, union members who work at the Teck were concerned about the smelters future. Teck had expanded its operations worldwide and the Trail operations only contributed CA$92 million of Tecks CA$3.3-billion gross profit in 2017. | 0 | Metallurgy |
The IF2 initiation factor is a crucial component in the process of protein synthesis. The largest among the three indispensable translation initiation factors is IF-2, which possesses a molecular mass of 97 kDa. The protein has many domains, including an N-terminal domain, a GTPase domain, a linker region, C1, C2, and C-terminal domains. The GTPase domain encompasses the G1-G5 motif, which is responsible for the binding and hydrolysis of GTP. The activity of IF2 is regulated by conformational changes induced by the binding and hydrolysis of GTP. The primary function of IF-2 is to transport the initiator fMet-tRNA to the P-site of the 30S ribosomal subunit. The C2 domain of IF2 has a unique recognition and binding affinity towards the initiator tRNA. The IF-2 protein has been observed to form a ternary complex when interacting with GTP and fMet-tRNA. This complex has been found to interact with the 30S subunit. The initiation of mRNA translation involves the placement of the start codon in the P-site through the codon-anticodon base matching with the tRNA anti-codon. IF2 regulates start codon selection accuracy and inhibits elongator tRNAs' binding by selectively binding to fMet-tRNA. Additionally, it relocates the initiator tRNA on the 30S subunit to enhance the optimum contact with the P-site. Furthermore, IF2 exhibits RNA chaperone activity, which enables it to rectify misfolded RNA structures. In general, the IF2 protein plays a crucial role in coordinating many steps of translation initiation, including the binding of mRNA and fMet-tRNA to the start codon, the joining of sub-units, and the activation of GTPase. | 1 | Gene expression + Signal Transduction |
C/EBPβ function is regulated by multiple mechanisms, including phosphorylation, acetylation, activation, autoregulation, and repression via other transcription factors, oncogenic elements, or chemokines. C/EBPβ can interact with CREB, NF-κB, and other proteins, leading to a trans-activation potential.
Phosphorylation of C/EBPβ can have an activation or a repression effect. For example, phosphorylation of threonine 235 in human C/EBPβ, or of threonine 188 in mouse and rat C/EBPβ, is important for C/EBPβ trans-activation capacity. Phosphorylation(s) of C/EBPβ in its regulatory domain can also modulate its function.
It was shown in C. elegans that multiple cis elements of cebp-1 mRNA 3UTR interact with mak-2' to upregulate expression of CEBP-1 in neuronal development. | 1 | Gene expression + Signal Transduction |
Compacted oxide layers can form due to sliding at low temperatures and offer some wear protection, however, in the absence of heat as a driving force (either due to frictional heating or higher ambient temperature), they cannot sinter together to form more protective glaze layers. | 0 | Metallurgy |
The Membership comprises almost 140 member companies in Europe as well as from the rest of the world. Members are:
* Coil coaters companies
* Paint, film and pre-treatment chemical suppliers
* Service centres/Stockholders
* Raw material suppliers
* Equipment manufacturers
* Technology providers
* Related associations/institutes
Member companies are e.g. Euramax Coated Products, ArcelorMittal, Tata Steel, Novelis, Hydro Aluminium, Becker Industrial Coatings, Akzo Nobel Industrial Finishes, BASF, Shingels, Henkel, Bronx… | 0 | Metallurgy |
In SARS-CoV-2 (COVID-19) infected Caco-2 cells, the phosphorylase activity of CK2 is increased resulting in phosphorylation of several cytoskeletal proteins. These infected cells also display CK2-containing filopodia protrusions associated with budding viral particles. Hence the protrusions may assist the virus in infecting adjacent cells. In these same cells, the CK2 inhibitor silmitasertib displayed potent antiviral activity. Senhwa Biosciences and the US National Institutes of Health have announced that they will evaluate the efficacy of silmitasertib in treating COVID-19 infections. | 1 | Gene expression + Signal Transduction |
Uncompetitive antagonists differ from non-competitive antagonists in that they require receptor activation by an agonist before they can bind to a separate allosteric binding site. This type of antagonism produces a kinetic profile in which "the same amount of antagonist blocks higher concentrations of agonist better than lower concentrations of agonist". Memantine, used in the treatment of Alzheimer's disease, is an uncompetitive antagonist of the NMDA receptor. | 1 | Gene expression + Signal Transduction |
The experimental archaeometallurgy of iron is more recent then that of copper in that for the most part was not widely studied until the mid-20th century. This can be attributed to the modern smelting of wrought iron still being produced as an industry up until 1900, when the last of the large-scale production shut down, along with the belief among researchers that many of the same techniques had been passed down since the inception of bloomery iron. A static technique simply was not the case as the technology used to make Roman Era iron showed the use of a technology that had long since disappeared. That being said research in iron has progressed beyond that of copper due to the greater amount of historic text and surviving remains of iron production.
Several experiments have taken place to reproduce bloomery iron. Clough presents an average example of experimental ironwork with the reproduction possible Roman bowl furnaces. Clough found the reproduction bowl furnaces to be inefficient by producing small amounts of poor quality iron, which, when compared to excavated findings of much larger better quality blooms of iron led to the conclusion that bowl furnaces were not used by the Romans. | 0 | Metallurgy |
One of the highest, at least in Western Europe, is in Loos-en-Gohelle in the former mining area of Pas-de-Calais, France. It comprises a range of five cones, of which two reach , surpassing the highest peak in Flanders, Mont Cassel. One of the regions of Europe most "littered" with (mountainous) spoil heaps is the Donbas, in Ukraine, especially around the city of Donetsk, which alone boasts about 130 of them.
In Ukrainian, they are called (; singular ) because of their shape.
In Heringen, Hesse, Germany, is the popularly called "Monte Kali", made of spoil from potash mining and rising some 200 meters above the surrounding terrain. "La Muntanya de Sal" (The Salt Mountain), another potash mine spoil heap, lies in Cardona, Catalonia, at about 120 meters in height. A larger and higher pile is that of "El runam del Cogulló" (The Spoil Heap of El Cogulló), also known as "El runam de la democràcia" (The Slag Heap of Democracy) or "Montsalat" (Salty Mountain), in Sallent, which has already grown higher than the small mountain it was named after (El Cogulló, 474 meters above sea level). | 0 | Metallurgy |
Multiple factors produced by the environment stimulate the corrosion and deterioration of concrete, such as freezing conditions, radiation exposure, and extensive heat cycles or freeze-thaw and wet-dry cycles. Cycles that cause mechanical breakdowns of concrete, such as freeze-thaw cycles, are incredibly ruinous. All these provide ways for microbes to take over, further eroding and weakening structures made of concrete. An uptick in damages on urbanized sewer systems and cities that line the coast has forced people to look further in-depth at how to preserve concrete from microbes.
To halt the damage done by microbes, a complete comprehension of corrosion-causing microbes must be undertaken. This includes knowing what the specific microbes and their community are made up of and how they break down structural concrete. Environmental stressors on structures often promote microbial corrosion caused by bacteria, Archaea, algae, and fungi. These microorganisms depend on their environment to provide proper moisture, pH levels, and resources that allow reproduction.
The pH level of concrete greatly influences what microbes can reproduce and how much damage is done to the concrete. A concrete surface is alkaline, making it difficult for microbes to germinate. However, chemical processes by the environment and microorganisms themselves cause changes in the concrete. Environmental conditions combined with carbonization caused by select microbes fabricate negative changes in the pH of the concrete. These few microbes can excrete metabolites that change the pH from 12 to 8. With a lower pH level, more microorganisms can survive on the concrete, thus quickening the corrosion rate. This becomes an extreme problem, as many microbes that attack concrete survive in anaerobic conditions. Sewers, for example, have low oxygen levels and are high in nitrogen and sulfuric gas, making them perfect for microbes that metabolize those gases. | 0 | Metallurgy |
Quorum sensing is used by bacteria to form biofilms. Quorum sensing is used by bacteria to form biofilms because the process determines if the minimum number of bacteria necessary for biofilm formation are present. The criteria to form a biofilm is dependent on a certain density of bacteria rather than a certain number of bacteria being present. When aggregated in high enough densities, some bacteria may form biofilms to protect themselves from biotic or abiotic threats. Quorum sensing is used by both Gram-positive and Gram-negative bacteria because it aids cellular reproduction. Once in a biofilm, bacteria can communicate with other bacteria of the same species. Bacteria can also communicate with other species of bacteria. This communication is enabled through autoinducers used by the bacteria.
Additionally, certain responses can be generated by the host organism in response to the certain bacterial autoinducers. Despite the fact that specific bacterial quorum sensing systems are different, for example the target genes, signal relay mechanisms, and chemical signals used between bacteria, the ability to coordinate gene expression for a specific species of bacteria remains the same. This ability alludes to the larger idea that bacteria have potential to become a multicellular bacterial body.
Secondly, biofilms may also serve to transport nutrients into the microbial community or transport toxins out by means of channels that permeate the extracellular polymeric matrix (like cellulose) that holds the cells together. Finally, biofilms are an ideal environment for horizontal gene transfer through either conjugation or environmental DNA (eDNA) that exists in the biofilm matrix.
The process of biofilm development is often triggered by environmental signals, and bacteria are proven to require flagella to successfully approach a surface, adhere to it, and form the biofilm. As cells either replicate or aggregate in a location, the concentration of autoinducers outside of the cells increases until a critical mass threshold is reached. At this point, it is energetically unfavorable for intracellular autoinducers to leave the cell and they bind to receptors and trigger a signaling cascade to initiate gene expression and begin secreting an extracellular polysaccharide to encase themselves inside. | 1 | Gene expression + Signal Transduction |
Friction stir processing can also be used to improve the microstructural properties of powder metal objects. In particular, when dealing with aluminium powder metal alloys, the aluminium oxide film on the surface of each granule is detrimental to the ductility, fatigue properties and fracture toughness of the workpiece. While conventional techniques for removing this film include forging and extrusion, friction stir processing is suited for situations where localized treatment is desired. | 0 | Metallurgy |
There are a few unusual circumstances where speleothems have been created in caves as a result of hyperalkaline leachate, with the same chemistry as occurs in [Equations to ]. This chemistry can occur when there is a source of concrete, lime, mortar or other manmade calcareous material located above a cave system and the associated hyperalkaline leachate can penetrate into the cave below. An example can be found in the Peak District – Derbyshire, England where pollution from 19th century industrial lime production has leached into the cave system below (e.g. Poole's Cavern) and created speleothems, such as stalactites and stalagmites. | 0 | Metallurgy |
RNA silencing describes several mechanistically related pathways which are involved in controlling and regulating gene expression. RNA silencing pathways are associated with the regulatory activity of small non-coding RNAs (approximately 20–30 nucleotides in length) that function as factors involved in inactivating homologous sequences, promoting endonuclease activity, translational arrest, and/or chromatic or DNA modification. In the context in which the phenomenon was first studied, small RNA was found to play an important role in defending plants against viruses. For example, these studies demonstrated that enzymes detect double-stranded RNA (dsRNA) not normally found in cells and digest it into small pieces that are not able to cause disease.
While some functions of RNA silencing and its machinery are understood, many are not. For example, RNA silencing has been shown to be important in the regulation of development and in the control of transposition events. RNA silencing has been shown to play a role in antiviral protection in plants as well as insects. Also in yeast, RNA silencing has been shown to maintain heterochromatin structure. However, the varied and nuanced role of RNA silencing in the regulation of gene expression remains an ongoing scientific inquiry. A range of diverse functions have been proposed for a growing number of characterized small RNA sequences—e.g., regulation of developmental, neuronal cell fate, cell death, proliferation, fat storage, haematopoietic cell fate, insulin secretion.
RNA silencing functions by repressing translation or by cleaving messenger RNA (mRNA), depending on the amount of complementarity of base-pairing. RNA has been largely investigated within its role as an intermediary in the translation of genes into proteins. More active regulatory functions, however, only began to be addressed by researchers beginning in the late-1990s. The landmark study providing an understanding of the first identified mechanism was published in 1998 by Fire et al., demonstrating that double-stranded RNA could act as a trigger for gene silencing. Since then, various other classes of RNA silencing have been identified and characterized. Presently, the therapeutic potential of these discoveries is being explored, for example, in the context of targeted gene therapy.
While RNA silencing is an evolving class of mechanisms, a common theme is the fundamental relationship between small RNAs and gene expression. It has also been observed that the major RNA silencing pathways currently identified have mechanisms of action which may involve both post-transcriptional gene silencing (PTGS) as well as chromatin-dependent gene silencing (CDGS) pathways. CDGS involves the assembly of small RNA complexes on nascent transcripts and is regarded as encompassing mechanisms of action which implicate transcriptional gene silencing (TGS) and co-transcriptional gene silencing (CTGS) events. This is significant at least because the evidence suggests that small RNAs play a role in the modulation of chromatin structure and TGS.
Despite early focus in the literature on RNA interference (RNAi) as a core mechanism which occurs at the level of messenger RNA translation, others have since been identified in the broader family of conserved RNA silencing pathways acting at the DNA and chromatin level. RNA silencing refers to the silencing activity of a range of small RNAs and is generally regarded as a broader category than RNAi. While the terms have sometimes been used interchangeably in the literature, RNAi is generally regarded as a branch of RNA silencing. To the extent it is useful to craft a distinction between these related concepts, RNA silencing may be thought of as referring to the broader scheme of small RNA related controls involved in gene expression and the protection of the genome against mobile repetitive DNA sequences, retroelements, and transposons to the extent that these can induce mutations. The molecular mechanisms for RNA silencing were initially studied in plants but have since broadened to cover a variety of subjects, from fungi to mammals, providing strong evidence that these pathways are highly conserved.
At least three primary classes of small RNA have currently been identified, namely: small interfering RNA (siRNA), microRNA (miRNA), and piwi-interacting RNA (piRNA). | 1 | Gene expression + Signal Transduction |
It is common to model such a network with a set of coupled ordinary differential equations (ODEs) or SDEs, describing the reaction kinetics of the constituent parts. Suppose that our regulatory network has nodes, and let represent the concentrations of the corresponding substances at time . Then the temporal evolution of the system can be described approximately by
where the functions express the dependence of on the concentrations of other substances present in the cell. The functions are ultimately derived from basic principles of chemical kinetics or simple expressions derived from these e.g. Michaelis–Menten enzymatic kinetics. Hence, the functional forms of the are usually chosen as low-order polynomials or Hill functions that serve as an ansatz for the real molecular dynamics. Such models are then studied using the mathematics of nonlinear dynamics. System-specific information, like reaction rate constants and sensitivities, are encoded as constant parameters.
By solving for the fixed point of the system:
for all , one obtains (possibly several) concentration profiles of proteins and mRNAs that are theoretically sustainable (though not necessarily stable). Steady states of kinetic equations thus correspond to potential cell types, and oscillatory solutions to the above equation to naturally cyclic cell types. Mathematical stability of these attractors can usually be characterized by the sign of higher derivatives at critical points, and then correspond to biochemical stability of the concentration profile. Critical points and bifurcations in the equations correspond to critical cell states in which small state or parameter perturbations could switch the system between one of several stable differentiation fates. Trajectories correspond to the unfolding of biological pathways and transients of the equations to short-term biological events. For a more mathematical discussion, see the articles on nonlinearity, dynamical systems, bifurcation theory, and chaos theory. | 1 | Gene expression + Signal Transduction |
Dislocation creep is a non-linear (plastic) deformation mechanism in which vacancies in the crystal glide and climb past obstruction sites within the crystal lattice. These migrations within the crystal lattice can occur in one or more directions and are triggered by the effects of increased differential stress. It occurs at lower temperatures relative to diffusion creep. The mechanical process presented in dislocation creep is called slip. The principal direction in which dislocation takes place are defined by a combination of slip planes and weak crystallographic orientations resulting from vacancies and imperfections in the atomic structure. Each dislocation causes a part of the crystal to shift by one lattice point along the slip plane, relative to the rest of the crystal. Each crystalline material has different distances between atoms or ions in the crystal lattice, resulting in different lengths of displacement. The vector that characterizes the length and orientation of the displacement is called the Burgers vector. The development of strong lattice preferred orientation can be interpreted as evidence for dislocation creep as dislocations move only in specific lattice planes.
Dislocation glide cannot act on its own to produce large strains due to the effects of strain-hardening, where a dislocation ‘tangle’ can inhibit the movement of other dislocations, which then pile up behind the blocked ones causing the crystal to become difficult to deform. Diffusion and dislocation creep can occur simultaneously. The effective viscosity of a stressed material under given conditions of temperature, pressure, and strain rate will be determined by the mechanism that delivers the smallest viscosity. Some form of recovery process, such as dislocation climb or grain-boundary migration must also be active. Slipping of the dislocation results in a more stable state for the crystal as the pre-existing imperfection is removed. It requires much lower differential stress than that required for brittle fracturing. This mechanism does not damage the mineral or reduce the internal strength of crystals. | 0 | Metallurgy |
Eshelby was born at Puddington, Cheshire, the son of Captain Alan Douglas Eshelby and Phoebe Mason Hutchinson. He was educated at St Cyprian's School, Eastbourne and was due to go to Charterhouse School but developed rheumatic fever and received his secondary education privately at home. At about this time the family moved to Manor House at Farrington Gurney, Somerset where his tutors were the village schoolmaster and a local clergyman. He relied extensively on self-instruction and obtained a place in the Physics Department of Bristol University and was awarded a first class honours in physics in 1937. He then worked in a research laboratory under H W B Skinner and W Sucksmith on magnetism and the soft X-ray spectra of solids. | 0 | Metallurgy |
On the basis of Mössbauer spectroscopic analysis, green rust minerals are suspected to occur as minerals in certain bluish-green soils that are formed in alternating redox conditions, and turn ochre once exposed to air. The green rust has been conjectured to be present in the form of the mineral fougerite. | 0 | Metallurgy |
PELP1 functions as a coactivator of several NRs and regulates genes involved in proliferation and cancer progression. PELP1 enhances transcription functions of ESR1, ESR2, AR, GR, E2F and STAT3. PELP1 participates in activation of ESR1 extra-nuclear actions by coupling ESR1 with Src kinase PI3K STAT3 ILK1 and mTOR PELP1 participates in E2-mediated cell proliferation and is a substrate of CDK4/cyclin D1, CDK2/cyclin E and CDK2/cyclin A complexes. Studies using TG mice model suggested the existence of an autocrine loop involving the CDK–cyclin D1–PELP1 axis in promoting mammary tumorigenesis
PELP1 has a histone binding domain; functions as a reader of histone modifications, interacts with epigenetic modifiers such as HDAC2, KDM1, PRMT6, CARM1; and facilitates activation of genes involved in proliferation and cancer progression. PELP1 modulates the expression of miRs, PELP1-mediated epigenetic changes play important role in the regulation miR expression and many of PELP1 mediated miRS are involved in promoting metastasis. PELP1 is needed for optimal DNA damage response, is phosphorylated by DDR kinases and is important for p53 coactivation function. PELP1 also interacts with MTp53, regulates its recruitment, and alters MTp53 target gene expression. PELP1 depletion contributes to increased stability of E2F1. PELP1 binds RNA, and participates in RNA splicing. The PELP1-regulated genome includes several uniquely spliced isoforms. Mechanistic studies showed that PELP1 interaction with the arginine methyltransferase PRMT6 plays a role in RNA splicing.
PELP1 plays critical roles in 60S ribosomal subunit synthesis and ribosomal RNA transcription. The SENP3-associated complex comprising PELP1, TEX10 and WDR18 is involved in maturation and nucleolar release of the large ribosomal subunit. SUMO conjugation/deconjugation of PELP1 controls its dynamic association with the AAA ATPase MDN1, a key factor of pre-60S remodeling. Modification of PELP1 promotes the recruitment of MDN1 to pre-60S particles, while deSUMOylation is needed to release both MDN1 and PELP1 from pre-ribosomes.
PELP1 is widely expressed in many regions of brain, including the hippocampus, hypothalamus, and cerebral cortex. PELP1 interacts with ESR1, Src, PI3K and GSK3β in the brain. It is essential for E2-mediated extra-nuclear signaling following global cerebral ischemic. PELP1 plays an essential role in E2-mediated rapid extranuclear signaling, neuroprotection, and cognitive function in the brain. Ability of E2 to exert anti-inflammatory effects was lost in PELP1 forebrain-specific knockout mice, indicating a key role for PELP1 in E2 anti-inflammatory signaling.
PELP1 is a proto-oncogene that provides cancer cells with a distinct growth and survival advantage. PELP1 interacts with various enzymes that modulate the cytoskeleton, cell
migration, and metastasis. PELP1 deregulation in vivo promotes development of mammary gland hyperplasia and carcinoma PELP1 is implicated in progression of breast, endometrial, ovarian, salivary prostate, lung, pancreas, and colon neoplasms.
PELP1 signaling contributes to hormonal therapy resistance. Altered localization of PLP1 contributes to tamoxifen resistance via excessive activation of the AKT pathway and cytoplasmic PELP1 induces signaling pathways that converge on ERRγ to promote cell survival in the presence of tamoxifen. AR, PELP1 and Src form constitutive complexes in prostate neoplasms model cells that exhibit androgen independence. Cytoplasmic localization of PELP1 upregulates pro-tumorigenic IKKε and secrete inflammatory signals, which through paracrine macrophage activation, regulate the migratory phenotype associated with breast cancer initiation. | 1 | Gene expression + Signal Transduction |
There are various methods of adequately identifying and monitoring hydrogen damage, including ultrasonic echo attenuation method, amplitude-based backscatter, velocity ratio, creeping waves/time-of-flight measurement, pitch-catch mode shear wave velocity, advanced ultrasonic backscatter techniques (AUBT), time of flight diffraction (TOFD), thickness mapping and in-situ metallography – replicas. For hydrogen damage, the backscatter technique is used to detect affected areas in the material. To cross-check and confirm the findings of the backscatter measurement, the velocity ratio measurement technique is used. For the detection of micro and macro cracks, time of flight diffraction is a suitable method to use. | 0 | Metallurgy |
After the end of the Hittite empire, from the 12th to 7th century BC, the city became the center of an independent Luwian Neo-Hittite state of Kammanu, also known as Malizi. A palace was built and monumental stone sculptures of lions and the ruler erected.
In the 12th century, Melid was probably dependent on Karkemiš, where king Kuzi-Tešub ruled. His two grandsons, Runtyas (Runtiya) and Arnuwantis, were at first appointed as “Country Lords” of Melid, but later they also became kings of Melid.
The encounter with the Assyrian king Tiglath-Pileser I (1115–1077 BC) resulted in the kingdom of Melid being forced to pay tribute to Assyria. Melid remained able to prosper until the Assyrian king Sargon II (722–705 BC) sacked the city in 712 BC. At the same time, the Cimmerians and Scythians invaded Anatolia and the city declined.
According to Igor Diakonoff and John Greppin, there was likely an Armenian presence in Melid by 1200 BCE. | 0 | Metallurgy |
Hepatocyte nuclear factors (HNFs) are a group of phylogenetically unrelated transcription factors that regulate the transcription of a diverse group of genes into proteins. These proteins include blood clotting factors and in addition, enzymes and transporters involved with glucose, cholesterol, and fatty acid transport and metabolism. | 1 | Gene expression + Signal Transduction |
UIT was originally developed in 1972 and has since been perfected by a team of Russian scientists under the leadership of Dr. Efim Statnikov. Originally developed and utilized to enhance the fatigue and corrosion attributes of ship and submarine structures, UIT has been utilized in aerospace, mining, offshore drilling, shipbuilding, infrastructure, automotive, energy production and other industries.
Different industrial solutions exist nowadays and are commercialized by a limited number of Original Equipment Manufacturers worldwide. | 0 | Metallurgy |
There is a collection of alternative splicing databases. These databases are useful for finding genes having pre-mRNAs undergoing alternative splicing and alternative splicing events or to study the functional impact of alternative splicing.
* AspicDB database
* Intronerator database
* ProSAS database | 1 | Gene expression + Signal Transduction |
Several methods are being pursued for controlling gene expression spatially, temporally and in different degrees. One method is by using operon inducer/repressor system which provides temporal control of gene expression. To control gene expression spatially inkjet printers are under development for printing ligands on gel culture. Other popular method involves use of light to control gene expression in spatiotemporal fashion. Since light can also be controlled easily in space, time and degree, several methods of controlling gene expression at DNA and RNA level have been developed and are under study. For example, RNA interference can be controlled using light and also patterning of gene expression has been performed in cell monolayer and in zebrafish embryos using caged morpholino or peptide nucleic acid demonstrating the control of gene expression spatiotemporally. Recently light based control has been shown at DNA level using transgene based system or caged triplex forming oligos | 1 | Gene expression + Signal Transduction |
Speisses are alloys of heavy metals like iron, cobalt, nickel and copper with arsenic, antimony and, occasionally, tin. The latter elements lower the melting point to around 1000 °C. Speisses commonly occur in lead smelting operations and copper smelting operations.
Speisses are only partially miscible with mattes, and if there is enough arsenic or antimony in the copper feed to a matte smelting furnace, a separate speiss melt can form. Speisses show high affinities for platinum group metals and gold. The mass concentration of platinum group metals in the speiss phase is about 1000 times that of the concentration in the matte phase, while the ratio for gold is about 100 times.
Speisses are also immiscible in liquid lead and flow out of lead blast furnaces as a separate phase. | 0 | Metallurgy |
In the 1990s, the Chinese government decided to increase the efficiency of the Chinese economy and reduce the environmental effects of heavy industry by modernising plants. As a response, the Yunnan Copper Corporation ("YCC") upgraded its existing plant, which was based on a sinter plant and an electric furnace, with a copper ISASMELT furnace. As with the Miami smelter, the electric furnace was converted from smelting duty to separation of matte and slag and providing matte surge capacity for the converters, and again, the small footprint of the ISASMELT furnace was very important in retrofitting it to the existing smelter.
The YCC ISASMELT plant had a design capacity of 600,000 dry t/y of copper concentrate and started smelting concentrate on 15 May 2002. YCC placed a lot of emphasis on training its operators, sending people to Mount Isa for training over a seven-month period during 2001 ahead of the ISASMELT commissioning. The total cost of the smelter modernisation program, including the ISASMELT furnace, was 640 million yuan (approximately US$80 million) and the smelter's concentrate treatment rate increased from 470,000 t/y to 800,000 t/y as a result.
The transfer of operating knowledge from MIM to YCC was sufficient for the first ISASMELT furnace refractory lining to last for two years, a marked improvement on the life of the initial lining of other plants.
YCC described the modernisation project as "a great success, achieving all that was expected." Energy consumption per tonne of blister copper produced decreased by 34% as a result of installing the ISASMELT furnace, and YCC estimated that during the first 38 months of operation, it saved approximately US$31.4 million through reduced energy costs alone, giving the modernisation a very short payback by industry standards.
In 2004, YCC's management was presented with awards for Innovation in Project Management and the National Medal for High Quality Projects by the Chinese government to mark the success of the smelter modernisation project.
Xstrata subsequently licensed YCC to build three more ISASMELT plants, one in Chuxiong in Yunnan Province, China to treat 500,000 t/y of copper concentrate, one in Liangshan in Sichuan Province, China and the other in Chambishi in Zambia to treat 350,000 t/y of concentrate. Chuxiong and Chambishi were commissioned in 2009. Liangshan was commissioned in 2012.
*Mopani Copper Mines, as part of Zambia Consolidated Copper Mines Limited | 0 | Metallurgy |
In April 1989, MIM Holdings Limited acquired the world rights to the Jameson Cell from TUNRA, with TUNRA retaining the rights to use the Cell for waste water treatment.
After the initial applications within the MIM Holdings group of companies, the years to 1994 saw Jameson Cells installed by various base and precious metals companies in Asia, South Africa, Canada and the United States, mainly in concentrate cleaning duties, but also in SX–EW electrolyte cleaning duties. The installation by Phelps Dodge (now Freeport-McMoRan) for electrolyte cleaning at its Morenci operation in Arizona was notable for having a large cell 6.5 m in diameter with 30 downcomers. The Morenci Jameson Cell consistently recovered over 82% of the organic extractant.
Toward the end of the period, Cells were installed in coal preparation plants operated by the BHP Mitsubishi Alliance and by Peabody for fines recovery. | 0 | Metallurgy |
Norşuntepe is a tell, or archaeological settlement mound, in Elazığ Province (Turkey). The site was occupied between the Chalcolithic and Iron Age and is now partially submerged by Lake Keban. It was excavated between 1968 and 1974. | 0 | Metallurgy |
Millesimal fineness is a system of denoting the purity of platinum, gold and silver alloys by parts per thousand of pure metal by mass in the alloy. For example, an alloy containing 75% gold is denoted as "750". Many European countries use decimal hallmark stamps (i.e., "585", "750", etc.) rather than "14 k", "18 k", etc., which is used in the United Kingdom and United States.
It is an extension of the older karat system of denoting the purity of gold by fractions of 24, such as "18 karat" for an alloy with 75% (18 parts per 24) pure gold by mass.
The millesimal fineness is usually rounded to a three figure number, particularly where used as a hallmark, and the fineness may vary slightly from the traditional versions of purity.
Here are the most common millesimal finenesses used for precious metals and the most common terms associated with them. | 0 | Metallurgy |
Regulatory networks allow bacteria to adapt to almost every environmental niche on earth. A network of interactions among diverse types of molecules including DNA, RNA, proteins and metabolites, is utilised by the bacteria to achieve regulation of gene expression. In bacteria, the principal function of regulatory networks is to control the response to environmental changes, for example nutritional status and environmental stress. A complex organization of networks permits the microorganism to coordinate and integrate multiple environmental signals.
One example stress is when the environment suddenly becomes poor of nutrients. This triggers a complex adaptation process in bacteria, such as E. coli. After this environmental change, thousands of genes change expression level. However, these changes are predictable from the topology and logic of the gene network that is reported in RegulonDB. Specifically, on average, the response strength of a gene was predictable from the difference between the numbers of activating and repressing input transcription factors of that gene. | 1 | Gene expression + Signal Transduction |
Ribosome profiling is a method that can reveal pausing sites through sequencing the ribosome protected fragments (RPFs or footprints) to map ribosome occupancy on the mRNA. Ribosome profiling has the ability to reveal the ribosome pause sites in the whole transcriptome. When the kinetics layer is added, it discloses the time of the pause, and the translation takes place. Ribosome profiling is however still in early stages and has biases that need to be explored further. Ribosome profiling allows for translation to be measured more accurately and precisely. During this process, translation needs to be stopped in order for ribosome profiling to be performed. This may cause a problem with ribosome profiling because the methods that are used to stop translation in an experiment can impact the outcome, which causes incorrect results. Ribosome profiling is useful for getting specific information on translation and the process of protein synthesis. | 1 | Gene expression + Signal Transduction |
The G protein-coupled receptors have seven hydrophobic transmembrane domains. Most of them are monomeric proteins, although GABA receptors require heterodimerization to function properly. The protein's N terminus is located on the extracellular side of the membrane and its C terminus is on the intracellular side.
The 7 transmembrane spanning domains, with an external amino terminus, are often claimed as being alpha helix shaped, and the polypeptide chain is said to be composed of around 450–550 amino acids. | 1 | Gene expression + Signal Transduction |
During the period of active colonization of the Urals, which began in the 14th to early 15th centuries, there were rumors about subsurface deposits in Perm land and Yugra. But when conditions were dangerous for the settlers, because of the indigenous population, industrial land development was practically not carried out. In 1491, Ivan III sent an expedition to the Northern Urals, to Pechora, with the task of searching for silver and copper ores. As a result, a small silver ore deposit was discovered on the Tsilma River, which was quickly developed. Ivan IV declared the prospecting and mining of ores a state monopoly and in 1567-1568 he sent an expedition to search for silver and copper ores on the Yayva River. The expedition ended in vain. In 1568, Ivan IV allocated extensive lands to Y. A. Stroganov in the Kama region with permission to use iron ores, but was banned from using silver, copper and tin ores, and he had to immediately report their discovery to Moscow.
The active resettlement of Russians to the Urals was facilitated by the agrarian crisis of the agricultural central part of Russia at the end of the 16th century. From 1579 to 1678 the Russian population of Great Perm increased from 2,197 to 11,811 households (by 463%). By 1724, the population of the Urals was already about 1 million people, while the total population of Russia was about 14 million people.
Until the beginning of the 17th century, all of the Ural and Russian metallurgy was locally handcrafted production in the form of small peasant blast furnaces and forges, in which all the processes of obtaining finished products were concentrated. | 0 | Metallurgy |
CREB-regulated transcription coactivator 3 is a protein that in humans is encoded by the CRTC3 gene.
This gene has been shown to be linked to weight gain. | 1 | Gene expression + Signal Transduction |
A 5 cap (also termed an RNA cap, an RNA 7-methylguanosine cap, or an RNA mG cap) is a modified guanine nucleotide that has been added to the "front" or 5 end of a eukaryotic messenger RNA shortly after the start of transcription. The 5 cap consists of a terminal 7-methylguanosine residue that is linked through a 5-5'-triphosphate bond to the first transcribed nucleotide. Its presence is critical for recognition by the ribosome and protection from RNases.
Cap addition is coupled to transcription, and occurs co-transcriptionally, such that each influences the other. Shortly after the start of transcription, the 5' end of the mRNA being synthesized is bound by a cap-synthesizing complex associated with RNA polymerase. This enzymatic complex catalyzes the chemical reactions that are required for mRNA capping. Synthesis proceeds as a multi-step biochemical reaction. | 1 | Gene expression + Signal Transduction |
Enhancers or cis-regulatory modules/elements (CRM/CRE) are non-coding DNA sequences containing multiple activator and repressor binding sites. Enhancers range from 200 bp to 1 kb in length and can be either proximal, 5’ upstream to the promoter or within the first intron of the regulated gene, or distal, in introns of neighboring genes or intergenic regions far away from the locus. Through DNA looping, active enhancers contact the promoter dependently of the core DNA binding motif promoter specificity. Promoter-enhancer dichotomy provides the basis for the functional interaction between transcription factors and transcriptional core machinery to trigger RNA Pol II escape from the promoter. Whereas one could think that there is a 1:1 enhancer-promoter ratio, studies of the human genome predict that an active promoter interacts with 4 to 5 enhancers. Similarly, enhancers can regulate more than one gene without linkage restriction and are said to “skip” neighboring genes to regulate more distant ones. Even though infrequent, transcriptional regulation can involve elements located in a chromosome different from one where the promoter resides. Proximal enhancers or promoters of neighboring genes can serve as platforms to recruit more distal elements. | 1 | Gene expression + Signal Transduction |
Although the new generation of mTOR inhibitors hold great promise for anticancer therapy and are rapidly moving into clinical trials, there are many important issues that determine their success in the clinic. First of all predictable biomarkers for benefit of these inhibitors are not available. It appears that genetic determinants predispose cancer cells to be sensitive or resistant to these compounds. Tumors that depend on PI3K/mTOR pathway should respond to these agents but it is unclear if compounds are effective in cancers with distinct genetic lesions.
Inhibition of mTOR is a promising strategy for treatment of number of cancers. Limited clinical activity of selective mTORC1 agents have made them unlikely to have impact in cancer treatment. The development of competitive ATP-catalytic inhibitors have the ability to block both mTORC1 and mTORC2. | 1 | Gene expression + Signal Transduction |
Several molecular biology studies during the 1950s indicated that RNA played some kind of role in protein synthesis, but that role was not clearly understood. For instance, in one of the earliest reports, Jacques Monod and his team showed that RNA synthesis was necessary for protein synthesis, specifically during the production of the enzyme β-galactosidase in the bacterium E. coli. Arthur Pardee also found similar RNA accumulation in 1954. In 1953, Alfred Hershey, June Dixon, and Martha Chase described a certain cytosine-containing DNA (indicating it was RNA) that disappeared quickly after its synthesis in E. coli. In hindsight, this may have been one of the first observations of the existence of mRNA but it was not recognized at the time as such.
The idea of mRNA was first conceived by Sydney Brenner and Francis Crick on 15 April 1960 at Kings College, Cambridge, while François Jacob was telling them about a recent experiment conducted by Arthur Pardee, himself, and Monod (the so-called PaJaMo experiment, which did not prove mRNA existed but suggested the possibility of its existence). With Cricks encouragement, Brenner and Jacob immediately set out to test this new hypothesis, and they contacted Matthew Meselson at the California Institute of Technology for assistance. During the summer of 1960, Brenner, Jacob, and Meselson conducted an experiment in Meselson's laboratory at Caltech which was the first to prove the existence of mRNA. That fall, Jacob and Monod coined the name "messenger RNA" and developed the first theoretical framework to explain its function.
In February 1961, James Watson revealed that his Harvard-based research group had been right behind them with a series of experiments whose results pointed in roughly the same direction. Brenner and the others agreed to Watsons request to delay publication of their research findings. As a result, the Brenner and Watson articles were published simultaneously in the same issue of Nature in May 1961, while that same month, Jacob and Monod published their theoretical framework for mRNA in the Journal of Molecular Biology'. | 1 | Gene expression + Signal Transduction |
Binding of a number of hormones and steroids, including testosterone, progesterone, and cholesterol, has been found to occur with sigma-2 receptors, though in some cases with lower affinity than to the sigma-1 receptor. Signaling caused by this binding is thought to occur via a calcium secondary messenger and calcium-dependent phosphorylation, and in association with sphingolipids following endoplasmic reticulum release of calcium. Known effects include decrease of expression of effectors in the mTOR pathway, and suppression of cyclin D1 and PARP-1. | 1 | Gene expression + Signal Transduction |
Bronze and brass are both copper alloys that are solid solution strengthened. Bronze is the result of adding about 12% tin to copper while brass is the result of adding about 34% zinc to copper. Both of these alloys are being utilized in coins production, ship hardware, and art. | 0 | Metallurgy |
Paired box protein Pax-6 in humans is a transcription factor, which is a main regulatory gene of eye and brain development. Ectopic expression of Drosophila homolog eyeless (ey) has been used to identify roles of Pax-6 in humans. Using tissue specific UAS-Gal4 system, ey can be induced on the legs, wings, halters and antennae of the transgenic flies to demonstrate that functions of ey. | 1 | Gene expression + Signal Transduction |
Corrosion fatigue is fatigue in a corrosive environment. It is the mechanical degradation of a material under the joint action of corrosion and cyclic loading. Nearly all engineering structures experience some form of alternating stress, and are exposed to harmful environments during their service life. The environment plays a significant role in the fatigue of high-strength structural materials like steel, aluminum alloys and titanium alloys. Materials with high specific strength are being developed to meet the requirements of advancing technology. However, their usefulness depends to a large extent on the degree to which they resist corrosion fatigue.
The effects of corrosive environments on the fatigue behavior of metals were studied as early as 1930.
The phenomenon should not be confused with stress corrosion cracking, where corrosion (such as pitting) leads to the development of brittle cracks, growth and failure. The only requirement for corrosion fatigue is that the sample be under tensile stress. | 0 | Metallurgy |
Calcium carbide is produced industrially in an electric arc furnace from a mixture of lime and coke at approximately . This is an endothermic reaction requiring per mole and high temperatures to drive off the carbon monoxide. This method has not changed since its invention in 1892:
:CaO + 3 C → CaC + CO
The high temperature required for this reaction is not practically achievable by traditional combustion, so the reaction is performed in an electric arc furnace with graphite electrodes. The carbide product produced generally contains around 80% calcium carbide by weight. The carbide is crushed to produce small lumps that can range from a few mm up to 50 mm. The impurities are concentrated in the finer fractions. The CaC content of the product is assayed by measuring the amount of acetylene produced on hydrolysis. As an example, the British and German standards for the content of the coarser fractions are 295 L/kg and 300 L/kg respectively (at 101 kPa pressure and temperature). Impurities present in the carbide include calcium phosphide, which produces phosphine when hydrolysed.
This reaction was an important part of the industrial revolution in chemistry, and was made possible in the United States as a result of massive amounts of inexpensive hydroelectric power produced at Niagara Falls before the turn of the 20th century.
The electric arc furnace method was discovered in 1892 by T. L. Willson, and independently in the same year by H. Moissan. In Jajce, Bosnia and Herzegovina, the Austrian industrialist Josef Kranz and his "Bosnische-Elektrizitäts AG" company, whose successor later became "Elektro-Bosna", opened the largest chemical factory for the production of calcium carbide at the time in Europe in 1899. A hydroelectric power station on the Pliva river with an installed capacity of 8 MW was constructed to supply electricity for the factory, the first power station of its kind in Southeast Europe, and became operational on 24 March 1899. | 0 | Metallurgy |
Some types of [http://www.epilepsy.com/ epilepsy] may be brought on due to a splice site mutation.
In addition to a mutation in a stop codon, a splice site mutation on the 3' strand was found in a gene coding for cystatin B in Progressive Myoclonus Epilepsy patients. This combination of mutations was not found in unaffected individuals. By comparing sequences with and without the splice site mutation, investigators were able to determine that a G-to-C nucleotide transversion occurs at the last position of the first intron. This transversion occurs in the region that codes for the cystatin B gene. Individuals suffering from Progressive Myoclonus Epilepsy possess a mutated form of this gene, which results in decreased output of mature mRNA, and subsequently decreases in protein expression.
A study has also shown that a type of Childhood Absence Epilepsy (CAE) causing febrile seizures may be linked to a splice site mutation in the sixth intron of the [https://www.ncbi.nlm.nih.gov/gene/2566 GABRG2 gene]. This splice site mutation was found to cause a nonfunctional GABRG2 subunit in affected individuals. According to this study, a point mutation was the culprit for the splice-donor site mutation, which occurred in intron 6. A nonfunctional protein product is produced, leading to the also nonfunctional subunit. | 1 | Gene expression + Signal Transduction |
Consider a point in a continuum under a state of plane stress, or plane strain, with stress components and all other stress components equal to zero (Figure 8.1). From static equilibrium of an infinitesimal material element at (Figure 8.2), the normal stress and the shear stress on any plane perpendicular to the - plane passing through with a unit vector making an angle of with the horizontal, i.e. is the direction cosine in the direction, is given by:
These equations indicate that in a plane stress or plane strain condition, one can determine the stress components at a point on all directions, i.e. as a function of , if one knows the stress components on any two perpendicular directions at that point. It is important to remember that we are considering a unit area of the infinitesimal element in the direction parallel to the - plane.
The principal directions (Figure 8.3), i.e., orientation of the planes where the shear stress components are zero, can be obtained by making the previous equation for the shear stress equal to zero. Thus we have:
and we obtain
This equation defines two values which are apart (Figure 8.3). The same result can be obtained by finding the angle which makes the normal stress a maximum, i.e.
The principal stresses and , or minimum and maximum normal stresses and , respectively, can then be obtained by replacing both values of into the previous equation for . This can be achieved by rearranging the equations for and , first transposing the first term in the first equation and squaring both sides of each of the equations then adding them. Thus we have
where
which is the equation of a circle of radius centered at a point with coordinates , called Mohr's circle. But knowing that for the principal stresses the shear stress , then we obtain from this equation:
When the infinitesimal element is oriented in the direction of the principal planes, thus the stresses acting on the rectangular element are principal stresses: and . Then the normal stress and shear stress as a function of the principal stresses can be determined by making . Thus we have
Then the maximum shear stress occurs when , i.e. (Figure 8.3):
Then the minimum shear stress occurs when , i.e. (Figure 8.3): | 0 | Metallurgy |
β-Catenin has been shown to interact with:
* APC,
* AXIN1,
* Androgen receptor,
* CBY1,
* CDH1,
* CDH2,
* CDH3,
* CDK5R1,
* CHUK,
* CTNND1,
* CTNNA1,
* EGFR,
* Emerin
* ESR1
* FHL2,
* GSK3B,
* HER2/neu,
* HNF4A,
* IKK2,
* LEF1 including transgenically,
* MAGI1,
* MUC1,
* NR5A1,
* PCAF,
* PHF17,
* Plakoglobin,
* PTPN14,
* PTPRF,
* PTPRK (PTPkappa),
*PTPRT (PTPrho),
*PTPRU (PCP-2),
* PSEN1,
* PTK7
* RuvB-like 1,
* SMAD7,
* SMARCA4
* SLC9A3R1,
* USP9X, and
* VE-cadherin.
* XIRP1 | 1 | Gene expression + Signal Transduction |
The human hNanog protein coded by the NANOG gene, consists of 305 amino acids and possesses 3 functional domains: the N-terminal domain, the C- terminal domain, and the conserved homeodomain motif. The homeodomain region facilitates DNA binding. The NANOG is located on chromosome 12, and the mRNA contains a 915 bp open reading frame (ORF) with 4 exons and 3 introns.
The N-terminal region of hNanog is rich in serine, threonine and proline residues, and the C-terminus contains a tryptophan-rich domain. The homeodomain in hNANOG ranges from residues 95 to 155. There are also additional NANOG genes (NANOG2, NANOG p8) which potentially affect ESCs differentiation. Scientists have shown that NANOG' is fundamental for self-renewal and pluripotency, and NANOG p8 is highly expressed in cancer cells. | 1 | Gene expression + Signal Transduction |
Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore. The process is based on the principle that precious metals typically oxidise or react chemically at much higher temperatures than base metals. When they are heated at high temperatures, the precious metals remain apart, and the others react, forming slags or other compounds.
Since the Early Bronze Age, the process was used to obtain silver from smelted lead ores. By the Middle Ages and the Renaissance, cupellation was one of the most common processes for refining precious metals. By then, fire assays were used for assaying minerals: testing fresh metals such as lead and recycled metals to determine their purity for jewellery and coin making. Cupellation is still in use today. | 0 | Metallurgy |
Anisomycin is used as a component of Martin Lewis agar, an in vitro diagnostic product which is used extensively in the United States for the selective isolation of Neisseria gonorrhoeae and Neisseria meningitidis. The antimicrobial can also be used in buffered charcoal yeast extract media for the selective isolation of Legionella species. | 1 | Gene expression + Signal Transduction |
Source:
Fretting also occurs on virtually all electrical connectors subject to motion (e.g. a printed circuit board connector plugged into a backplane, i.e. SOSA/VPX). Commonly most board to board (B2B) electrical connectors are especially vulnerable if there is any relative motion present between the mating connectors. A mechanically rigid connection system is required to hold both halves of a B2B motionless (often impossible). Wire to board (W2B) connectors tend to be immune to fretting because the wire half of the connector acts as a spring absorbing relative motion that would otherwise transfer to the contact surfaces of the W2B connector. Very few exotic B2B connectors exist that address fretting by: 1) incorporating springs into the individual contacts or 2) using a Chinese finger trap design to greatly increase the contact area. A connector design that contacts all 4-sides of a square pin instead of just one or 1 or 2 can delay the inevitable fretting some amount. Keeping contacts clean and lubricated also offers some longevity.
Contact fretting can change the impedance of a B2B connector from milliohms to ohms in just minutes when vibration is present. The relatively soft and thin gold plating used on most high quality electrical connectors is quickly worn through exposing the underlying alloy metals and with fretting debris the impedance rapidly increases. Somewhat counterintuitively, high contact forces on the mated connector pair (thought to help lower impedance and increase reliability) can actually make the rate of fretting even worse. | 0 | Metallurgy |
The process of activation and binding in eukaryotes is different from bacteria in the way that specific DNA elements bind the factors for a functional pre-initiation complex. In bacteria there is a single polymerase, that contain catalytic subunits and a single regulatory subunits known as sigma, which transcribe for different type of genes.
In eukaryotes, the transcription is performed by three different RNA polymerase, RNA pol I for ribosomal RNAs (rRNAs), RNA polymerase II for messenger RNAs (mRNAs) and some small regulatory RNAs, and the RNA polymerase III for small RNAs such as transfer RNAs (tRNAs). The process of positioning of the RNA polymerase II and the transcriptional machinery require the recognition of a region known as "core promoter". The elements that could be found in the core promoter include the TATA element, the TFIIB recognition element (BRE), the initiator (Inr), and the downstream core promoter element (DPE). Promoters in eukaryotes contain one or more of these core promotes elements (but any of them are absolutely essential for promoter function), these elements are binding sites for subunits of the transcriptional machinery and are involve in the initiation of the transcription, but also they have some specific enhancer functions. In addition, the promoter activity in eukaryotes include some complexities in the way of how they integrate signals from distal factors with the core promoter. | 1 | Gene expression + Signal Transduction |
Zinc was extracted in India as early as in the 4th to 3rd century BCE. Zinc production may have begun in India, and ancient northwestern India is the earliest known civilization that produced zinc on an industrial scale. The distillation technique was developed around 1200 CE at Zawar in Rajasthan.
In the 17th century, China exported Zinc to Europe under the name of totamu or tutenag. The term tutenag may derive from the South Indian term Tutthanagaa (zinc). In 1597, Libavius, a metallurgist in England received some quantity of Zinc metal and named it as Indian/Malabar lead. In 1738, William Champion is credited with patenting in Britain a process to extract zinc from calamine in a smelter, a technology that bore a strong resemblance to and was probably inspired by the process used in the Zawar zinc mines in Rajasthan. His first patent was rejected by the patent court on grounds of plagiarising the technology common in India. However, he was granted the patent on his second submission of patent approval. Postlewayts Universal Dictionary of 1751 still wasnt aware of how Zinc was produced.
The Arthashastra describes the production of zinc. The Rasaratnakara by Nagarjuna describes the production of brass and zinc. There are references of medicinal uses of zinc in the Charaka Samhita (300 BCE). The Rasaratna Samuchaya (800 CE) explains the existence of two types of ores for zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purpose. It also describes two methods of zinc distillation. | 0 | Metallurgy |
Earlier converters, with a false bottom that can be detached and repaired, are still in use. Modern converters have a fixed bottom with plugs for argon purging. The energy optimization furnace (EOF) is a BOF variant associated with a scrap preheater where the sensible heat in the off-gas is used for preheating scrap, located above the furnace roof.
The lance used for blowing has undergone changes. Slagless lances, with a long tapering copper tip, have been employed to avoid jamming of the lance during blowing. Post-combustion lance tips burn the CO generated during blowing into carbon dioxide| and provide additional heat. For slag-free tapping, darts, refractory balls, and slag detectors are employed. Modern converters are fully automated with automatic blowing patterns and sophisticated control systems. | 0 | Metallurgy |
Tilt filling, also known as tilt casting, is an uncommon filling technique where the crucible is attached to the gating system and both are slowly rotated so that the metal enters the mold cavity with little turbulence. The goal is to reduce porosity and inclusions by limiting turbulence. For most uses tilt filling is not feasible because the following inherent problem: if the system is rotated slow enough to not induce turbulence, the front of the metal stream begins to solidify, which results in mis-runs. If the system is rotated faster it induces turbulence, which defeats the purpose. Durville of France was the first to try tilt casting, in the 1800s. He tried to use it to reduce surface defects when casting coinage from aluminium bronze. | 0 | Metallurgy |
When a splice site mutation occurs in intron 2 of the gene that produces the parathyroid hormone, a parathyroid deficiency can prevail. In one particular study, a G to C substitution in the splice site of intron 2 produces a skipping effect in the messenger RNA transcript. The exon that is skipped possesses the initiation start codon to produce parathyroid hormone. Such failure in initiation causes the deficiency. | 1 | Gene expression + Signal Transduction |
Typically bainite manifests as aggregates, termed sheaves, of ferrite plates (sub-units) separated by retained austenite, martensite or cementite. While the sub-units appear separate when viewed on a 2-dimensional section they are in fact interconnected in 3-dimensions and usually take on a lenticular plate or lath morphology. The sheaves themselves are wedge-shaped with the thicker end associated with the nucleation site.
The thickness of the ferritic plates is found to increase with the transformation temperature. Neural network models have indicated that this is not a direct effect of the temperature per se but rather a result of the temperature dependence of the driving force for the reaction and the strength of the austenite surrounding the plates. At higher temperatures, and hence lower undercooling, the reduced thermodynamic driving force causes a decrease in the nucleation rate which allows individual plates to grow larger before they physically impinge on each other. Further, the growth of the plates must be accommodated by plastic flow in the surrounding austenite which is difficult if the austenite is strong and resists the plate's growth. | 0 | Metallurgy |
Because natural moissanite is extremely scarce, most silicon carbide is synthetic. Silicon carbide is used as an abrasive, as well as a semiconductor and diamond simulant of gem quality. The simplest process to manufacture silicon carbide is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at a high temperature, between and . Fine SiO particles in plant material (e.g. rice husks) can be converted to SiC by heating in the excess carbon from the organic material. The silica fume, which is a byproduct of producing silicon metal and ferrosilicon alloys, can also be converted to SiC by heating with graphite at .
The material formed in the Acheson furnace varies in purity, according to its distance from the graphite resistor heat source. Colorless, pale yellow and green crystals have the highest purity and are found closest to the resistor. The color changes to blue and black at greater distance from the resistor, and these darker crystals are less pure. Nitrogen and aluminium are common impurities, and they affect the electrical conductivity of SiC.
Pure silicon carbide can be made by the Lely process, in which SiC powder is sublimed into high-temperature species of silicon, carbon, silicon dicarbide (SiC), and disilicon carbide (SiC) in an argon gas ambient at 2500 °C and redeposited into flake-like single crystals, sized up to 2 × 2 cm, at a slightly colder substrate. This process yields high-quality single crystals, mostly of 6H-SiC phase (because of high growth temperature).
A modified Lely process involving induction heating in graphite crucibles yields even larger single crystals of 4 inches (10 cm) in diameter, having a section 81 times larger compared to the conventional Lely process.
Cubic SiC is usually grown by the more expensive process of chemical vapor deposition (CVD) of silane, hydrogen and nitrogen. Homoepitaxial and heteroepitaxial SiC layers can be grown employing both gas and liquid phase approaches.
To form complexly shaped SiC, preceramic polymers can be used as precursors which form the ceramic product through pyrolysis at temperatures in the range 1000–1100 °C. Precursor materials to obtain silicon carbide in such a manner include polycarbosilanes, poly(methylsilyne) and polysilazanes. Silicon carbide materials obtained through the pyrolysis of preceramic polymers are known as polymer derived ceramics or PDCs. Pyrolysis of preceramic polymers is most often conducted under an inert atmosphere at relatively low temperatures. Relative to the CVD process, the pyrolysis method is advantageous because the polymer can be formed into various shapes prior to thermalization into the ceramic.
SiC can also be made into wafers by cutting a single crystal either using a diamond wire saw or by using a laser. SiC is a useful semiconductor used in power electronics. | 0 | Metallurgy |
Huntingtin protein co-localizes with ATM repair protein at sites of DNA damage. Huntingtin is a scaffolding protein in the ATM oxidative DNA damage response complex. Huntingtons disease patients with aberrant huntingtin protein are deficient in repair of oxidative DNA damage. Oxidative DNA damage appears to underlie Huntingtons disease pathogenesis. Huntington's disease is likely caused by the dysfunction of mutant huntingtin scaffold protein in DNA repair leading to increased oxidative DNA damage in metabolically active cells. | 1 | Gene expression + Signal Transduction |
The function of neurons depends upon cell polarity. The distinctive structure of nerve cells allows action potentials to travel directionally (from dendrites to cell body down the axon), and for these signals to then be received and carried on by post-synaptic neurons or received by effector cells. Nerve cells have long been used as models for cellular polarization, and of particular interest are the mechanisms underlying the polarized localization of synaptic molecules. PIP2 signaling regulated by IMPase plays an integral role in synaptic polarity.
Phosphoinositides (PIP, PIP2, and PIP3) are molecules that have been shown to affect neuronal polarity. A gene (ttx-7) was identified in Caenorhabditis elegans that encodes myo-inositol monophosphatase (IMPase), an enzyme that produces inositol by dephosphorylating inositol phosphate. Organisms with mutant ttx-7 genes demonstrated behavioral and localization defects, which were rescued by expression of IMPase. This led to the conclusion that IMPase is required for the correct localization of synaptic protein components. The egl-8 gene encodes a homolog of phospholipase Cβ (PLCβ), an enzyme that cleaves PIP2. When ttx-7 mutants also had a mutant egl-8 gene, the defects caused by the faulty ttx-7 gene were largely reversed. These results suggest that PIP2 signaling establishes polarized localization of synaptic components in living neurons. | 1 | Gene expression + Signal Transduction |
The Hall–Petch relation predicts that as the grain size decreases the yield strength increases. The Hall–Petch relation was experimentally found to be an effective model for materials with grain sizes ranging from 1 millimeter to 1 micrometer. Consequently, it was believed that if average grain size could be decreased even further to the nanometer length scale the yield strength would increase as well. However, experiments on many nanocrystalline materials demonstrated that if the grains reached a small enough size, the critical grain size which is typically around , the yield strength would either remain constant or decrease with decreasing grains size. This phenomenon has been termed the reverse or inverse Hall–Petch relation. A number of different mechanisms have been proposed for this relation. As suggested by Carlton et al., they fall into four categories: (1) dislocation-based, (2) diffusion-based, (3) grain-boundary shearing-based, (4) two-phase-based.
There have been several works done to investigate the mechanism behind the inverse Hall–Petch relationship on numerous materials. In Han’s work, a series of molecular dynamics simulations were done to investigate the effect of grain size on the mechanical properties of nanocrystalline graphene under uniaxial tensile loading, with random shapes and random orientations of graphene rings. The simulation was run at grain sizes of nm and at room temperature. It was found that in the grain size of range 3.1 nm to 40 nm, inverse Hall–Petch relationship was observed. This is because when the grain size decreases at nm scale, there is an increase in the density of grain boundary junctions which serves as a source of crack growth or weak bonding. However, it was also observed that at grain size below 3.1 nm, a pseudo Hall–Petch relationship was observed, which results an increase in strength. This is due to a decrease in stress concentration of grain boundary junctions and also due to the stress distribution of 5-7 defects along the grain boundary where the compressive and tensile stress are produced by the pentagon and heptagon rings, etc. Chen at al. have done research on the inverse HallPetch relations of high-entropy CoNiFeAlCu alloys. In the work, polycrystalline models of FCC structured CoNiFeAlCu with grain sizes ranging from 7.2 nm to 18.8 nm were constructed to perform uniaxial compression using molecular dynamic simulations. All compression simulations were done after setting the periodic boundary conditions across the three orthogonal directions. It was found that when the grain size is below 12.1 nm the inverse Hall–Petch relation was observed. This is because as the grain size decreases partial dislocations become less prominent and so as deformation twinning. Instead, it was observed that there is a change in the grain orientation and migration of grain boundaries and thus cause the growth and shrinkage of neighboring grains. These are the mechanisms for inverse Hall–Petch relations. Sheinerman et al. also studied inverse Hall–Petch relation for nanocrystalline ceramics. It was found that the critical grain size for the transition from direct Hall–Petch to inverse Hall–Petch fundamentally depends on the activation energy of grain boundary sliding. This is because in direct Hall–Petch the dominant deformation mechanism is intragrain dislocation motion while in inverse Hall–Petch the dominant mechanism is grain boundary sliding. It was concluded that by plotting both the volume fraction of grain boundary sliding and volume fraction of intragrain dislocation motion as a function of grain size, the critical grain size could be found where the two curves cross.
Other explanations that have been proposed to rationalize the apparent softening of metals with nanosized grains include poor sample quality and the suppression of dislocation pileups.
The pileup of dislocations at grain boundaries is a hallmark mechanism of the Hall–Petch relationship. Once grain sizes drop below the equilibrium distance between dislocations, though, this relationship should no longer be valid. Nevertheless, it is not entirely clear what exactly the dependency of yield stress should be on grain sizes below this point. | 0 | Metallurgy |
Arsenical bronze is an alloy in which arsenic, as opposed to or in addition to tin or other constituent metals, is combined with copper to make bronze. The use of arsenic with copper, either as the secondary constituent or with another component such as tin, results in a stronger final product and better casting behavior.
Copper ore is often naturally contaminated with arsenic; hence, the term "arsenical bronze" when used in archaeology is typically only applied to alloys with an arsenic content higher than 1% by weight, in order to distinguish it from potentially accidental additions of arsenic. | 0 | Metallurgy |
In-situ synchrotron diffraction experiment on Electron alloy-WE 43 (Mg4Y3Nd) shows that this alloy form the following intermetallic phases ;Mg12Nd, Mg14Y4Nd, and Mg24Y5. | 0 | Metallurgy |
In materials science and materials engineering, uranium metallurgy is the study of the physical and chemical behavior of uranium and its alloys.
Commercial-grade uranium can be produced through the reduction of uranium halides with alkali or alkaline earth metals. Uranium metal can also be made through electrolysis of KUF or UF, dissolved in a molten CaCl and NaCl. Very pure uranium can be produced through the thermal decomposition of uranium halides on a hot filament.
The uranium isotope U is used as the fuel for nuclear reactors and nuclear weapons. It is the only isotope existing in nature to any appreciable extent that is fissile, that is, fissionable by thermal neutrons. The isotope U is also important because it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope 239Pu (plutonium), which also is fissile. Uranium in its natural state comprises just 0.71% U and 99.3% U, and the main focus of uranium metallurgy is the enrichment of uranium through isotope separation. | 0 | Metallurgy |
ARTADE (ARabidopsis Tiling Array-based Detection of Exons) is a database for the annotation of genome-wide tiling-array data in Arabidopsis | 1 | Gene expression + Signal Transduction |
After Falconbridge’s 1992 decision to market the Kidd technology, the Falconbridge and the then MIM Process Technologies groups competed for the tank house technology market. Between 1992 and 2006, 25 Kidd technology licences were sold, while there were 52 Isa process licences sold in the same period.
Xstrata plc (now Glencore) took over MIM Holdings in 2003. The Isa Process technology continued to be developed and marketed by Xstrata Technology. Xstrata subsequently took over Falconbridge in 2006. The Kidd Process technology consequently became part of the Xstrata Technology tank house package and together they began to be marketed as IsaKidd, a name that represents the dual heritage of the technology.
The result has been a technology package that combined what were mutually regarded as the best of both versions. This combination led to the development of new stripping systems and new cathode designs are in development.
The variation in copper deposits on the cathode plates was one of the difficulties encountered with the earlier stripping machines. Areas of thin copper on the cathode plates, which are caused by short circuits, are difficult to separate from the stainless steel plate due to their lack of rigidity. Plates bearing such areas generally had to be rejected from the stripping machine and stripped manually. Similarly, sticky copper deposits (generally related to poor surface condition on the cathode plate, such as corroded surfaces or improper mechanical treatment), heavily nodulated cathode and laminated copper caused problems for stripping.
Stripping machine development focussed on developing a device that could be seen as a more accommodating and universal stripping machine that could handle cathode plates with problem copper deposits without rejecting them or slowing the stripping rate.
The result of this work was a new robotic cathode stripping machine. It incorporated the following features:
* a stripping wedge that starts removing the copper from the top of the cathode plate and moves down to the bottom
* guides to support the copper during the downwards motion to ensure that the copper does not strip prematurely
* rollers designed to reduce the friction between the copper, the cathode plate and the wedge during the downward motion of the wedge
* grippers that clamp the copper before it is pulled away from the cathode plate.
The stripping wedges are mounted on two robotic arms, one for each side of the cathode plate. These arms strip the copper from the plate and lay the sheets of cathode copper onto conveyors for them to be taken away for bundling. | 0 | Metallurgy |
The specific study of the ferrous compounds (those including iron, Fe) used in the past. Iron metal was first encountered in meteorites, and was later extracted from iron ores to create wrought iron which was never fully molten, and later, cast iron. Iron combined with carbon formed steel, allowing people to develop superior tools and weapons from the Iron Age to the industrial revolution. | 0 | Metallurgy |
The Jameson Cell is a high-intensity froth flotation cell that was invented by Laureate Professor Graeme Jameson of the University of Newcastle (Australia) and developed in conjunction with Mount Isa Mines Limited ("MIM", a subsidiary of MIM Holdings Limited and now part of the Glencore group of companies). | 0 | Metallurgy |
Duplex stainless steel is widely used in industry because it possesses excellent oxidation resistance, but it can have limited toughness due to its large ferritic grain size and embrittlement tendencies at temperatures ranging from 280–500 °C, especially at 475 °C, where spinodal decomposition of the supersaturated solid ferrite solution into Fe-rich nanophase () and Cr-rich nanophase (), accompanied by G-phase precipitation, occurs, which makes the ferrite phase a preferential initiation site for micro-cracks. | 0 | Metallurgy |