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UPdAl is a heavy-fermion superconductor with a hexagonal crystal structure and critical temperature T=2.0K that was discovered in 1991. Furthermore, UPdAl orders antiferromagnetically at T=14K, and UPdAl thus features the unusual behavior that this material, at temperatures below 2K, is simultaneously superconducting and magnetically ordered.
Later experiments demonstrated that superconductivity in UPdAl is magnetically mediated, and UPdAl therefore serves as a prime example for non-phonon-mediated superconductors. | 0 | Metallurgy |
One short inscription on the pillar is associated with the Tomara king Anangpal, although it is hard to decipher.. Alexander Cunningham (1862–63) read the inscription as follows:
Based on this reading, Cunningham theorized that Anangpal had moved the pillar to its current location while establishing the city of Delhi. However, his reading has been contested by the later scholars. Buddha Rashmi Mani (1997) read it as follows: | 0 | Metallurgy |
Alternative splicing was first observed in 1977. The adenovirus produces five primary transcripts early in its infectious cycle, prior to viral DNA replication, and an additional one later, after DNA replication begins. The early primary transcripts continue to be produced after DNA replication begins. The additional primary transcript produced late in infection is large and comes from 5/6 of the 32kb adenovirus genome. This is much larger than any of the individual adenovirus mRNAs present in infected cells. Researchers found that the primary RNA transcript produced by adenovirus type 2 in the late phase was spliced in many different ways, resulting in mRNAs encoding different viral proteins. In addition, the primary transcript contained multiple polyadenylation sites, giving different 3’ ends for the processed mRNAs.
In 1981, the first example of alternative splicing in a transcript from a normal, endogenous gene was characterized. The gene encoding the thyroid hormone calcitonin was found to be alternatively spliced in mammalian cells. The primary transcript from this gene contains 6 exons; the calcitonin mRNA contains exons 1–4, and terminates after a polyadenylation site in exon 4. Another mRNA is produced from this pre-mRNA by skipping exon 4, and includes exons 1–3, 5, and 6. It encodes a protein known as CGRP (calcitonin gene related peptide). Examples of alternative splicing in immunoglobin gene transcripts in mammals were also observed in the early 1980s.
Since then, many other examples of biologically relevant alternative splicing have been found in eukaryotes. The "record-holder" for alternative splicing is a D. melanogaster gene called Dscam, which could potentially have 38,016 splice variants.
In 2021, it was discovered that the genome of adenovirus type 2, the adenovirus in which alternative splicing was first identified, was able to produce a much greater variety of mRNA than previously thought. By using next generation sequencing technology, researchers were able to update the human adenovirus type 2 transcriptome, and present a mind-boggling 904 unique mRNA, produced by the virus through a complex pattern of alternative splicing. Very few of these splice variants have been shown to be functional, a point that the authors raise in their paper.
::"An outstanding question is what roles the menagerie of novel RNAs play or whether they are spurious molecules generated by an overloaded splicing machinery." | 1 | Gene expression + Signal Transduction |
The idea of interstitial compounds was started in the late 1930s and they are often called Hagg phases after Hägg. Transition metals generally crystallise in either the hexagonal close packed or face centered cubic structures, both of which can be considered to be made up of layers of hexagonally close packed atoms. In both of these very similar lattices there are two sorts of interstice, or hole:
*Two tetrahedral holes per metal atom, i.e. the hole is between four metal atoms
*One octahedral hole per metal atom, i.e. the hole is between six metal atoms
It was suggested by early workers that:
*the metal lattice was relatively unaffected by the interstitial atom
*the electrical conductivity was comparable to that of the pure metal
*there was a range of composition
*the type of interstice occupied was determined by the size of the atom
These were not viewed as compounds, but rather as solutions, of say carbon, in the metal lattice, with a limiting upper “concentration” of the smaller atom that was determined by the number of interstices available. | 0 | Metallurgy |
The candidate division SR1 and gracilibacteria code (translation table 25) is used in two groups of (so far) uncultivated bacteria found in marine and fresh-water environments and in the intestines and oral cavities of mammals among others. The difference to the standard and the bacterial code is that UGA represents an additional glycine codon and does not code for termination. | 1 | Gene expression + Signal Transduction |
Shape-memory alloys are typically made by casting, using vacuum arc melting or induction melting. These are specialist techniques used to keep impurities in the alloy to a minimum and ensure the metals are well mixed. The ingot is then hot rolled into longer sections and then drawn to turn it into wire.
The way in which the alloys are "trained" depends on the properties wanted. The "training" dictates the shape that the alloy will remember when it is heated. This occurs by heating the alloy so that the dislocations re-order into stable positions, but not so hot that the material recrystallizes. They are heated to between and for 30 minutes, shaped while hot, and then are cooled rapidly by quenching in water or by cooling with air. | 0 | Metallurgy |
"Upper bainite" forms around 400–550 °C in sheaves. These sheaves contain several laths of ferrite that are approximately parallel to each other and which exhibit a Kurdjumov-Sachs relationship with the surrounding austenite, though this relationship degrades as the transformation temperature is lowered. The ferrite in these sheaves has a carbon concentration below 0.03%, resulting in carbon-rich austenite around the laths.
The amount of cementite that forms between the laths is based on the carbon content of the steel. For a low carbon steel, typically discontinuous "stringers" or small particles of cementite will be present between laths. For steel with a higher carbon content, the stringers become continuous along the length of the adjacent laths. | 0 | Metallurgy |
The lost-wax casting process may also be used in the production of cast glass sculptures. The original sculpture is made from wax. The sculpture is then covered with mold material (e.g., plaster), except for the bottom of the mold which must remain open. When the mold has hardened, the encased sculpture is removed by applying heat to the bottom of the mold. This melts out the wax (the wax is lost) and destroys the original sculpture. The mold is then placed in a kiln upside down with a funnel-like cup on top that holds small chunks of glass. When the kiln is brought up to temperature (1450-1530 degrees Fahrenheit), the glass chunks melt and flow down into the mold. Annealing time is usually 3–5 days, and total kiln time is 5 or more days. After the mold is removed from the kiln, the mold material is removed to reveal the sculpture inside. | 0 | Metallurgy |
The first period of metallurgical production in the Urals date back to the 4th and 3rd millennia BC. During the Bronze Age, primitive copper-bronze metallurgy was developed among the pastoral tribes of the Urals. The beginning of the development of the Kargalinsky copper ore deposit, located along the Kargalka and Yangiz Rivers, began during this period. In the first half of the third millennium BC, centers of copper metallurgy were formed in the Western Urals and in the Kama region, the ore base that provided numerous mineral deposits of copper sandstone.
The second millennium BC was characterized by the massive spread of copper-bronze metallurgy practically throughout the Urals, and the development of new technologies and metal processing. The Seima-Turbino phenomenon of the distribution of high-quality bronze products in the vast expanses of the forest-steppe zone of Eurasia belongs to this period. The centers of metallurgy of the Southern Urals of the 2nd millennium BC include settlements of the Sintashta, Abashevo and Arkaim cultures. The development of bronze metallurgy in the Urals was hindered by the lack of tin deposits, the alloying of copper which allowed to obtain high-quality bronze. Therefore, the metal objects found at the excavations of the Bronze Age settlements are mainly represented by products made of ordinary copper and arsenic bronze.
During the period from the end of the 2nd millennium BC to the beginning of the 1st millennium BC, the most ore-rich areas of the southern Ural copper mines were depleted and abandoned. In the middle of the first millennium BC, metallurgical products were mastered by representatives of Srubnaya culture. In the second half of the 1st millennium BC, there were isolated pockets of Ananyino culture in the Kama-Volga region and Itkul culture in the Urals.
The appearance of iron in the Urals dates back to the 1st millennium BC. In the Kama-Volga region iron products were made from the 8th to the 6th centuries BC, and in the Ural Mountains from the fifth to the fourth centuries BC. In general, the massive penetration of primitive iron metallurgy with the use of forges in the Urals began in the middle of the 1st millennium BC. Forest tribes of the northern Urals and in the north of Western Siberia mastered iron metallurgy by the end of the 1st millennium BC. In the settlements of the Gorokhovo and Kara-Abyz cultures, along with bronze, iron products were found to be in use.
The 1st millennium AD was characterized by the massive distribution of iron in the Urals and Western Siberia. The oldest blast furnace in the Urals, belonging to the Pyanoborsk culture, was discovered by Vladimir Gening at the settlement of Cheganda I, on the territory of modern Udmurtia. Also, for the settlements of the Upper Kama region at the beginning of the Iron Age, the separation of metallurgical production into a separate craft was characteristic, which made up the specialization of entire villages or parts of them. The spread of iron crafts was facilitated by the resettlement of the Ugric tribes of the Petrogrom culture in the Urals. Remains of iron-smelting furnaces of the 6th-9th centuries were found during excavations of hill forts near modern Yekaterinburg.
In the 11th to the 13th centuries, metal goods made by Western European artisans began to penetrate the Urals through trade routes, which contributed to the expansion of the range of products smelted. Excavations at the Kama settlements or hill forts of Idnakar, Vasyakar, Dondykar, Kushmansky, and others have shown that in the 11th to the 15th centuries the main unit for smelting iron was a blast furnace. The metalworking complexes consisted of forges and tool kits. The development of heat treatment and welding of metals proceeded unevenly throughout the Urals. In the 1st millennium, the main products of metallurgists were items for military and hunting purposes: arrowheads, spears, axes, knives, and fishhooks. From the beginning of the second millennium, agricultural implements began to predominate.
By the end of the 1st millennium, ore mining and its own copper-bronze and iron production in the Urals gradually ceased due to the depletion of available resources, competition with more developed cultures, and ethnographic changes that had begun. The penetration of Russians into the Urals, associated mainly with the abundance of furs in the region, facilitated the infiltration of new technologies, including metallurgical ones. In the 17th to the 18th centuries, abandoned ancient mines served as a kind of indicator for geologists in search of ore. With the help of such finds, the Gumeshev and Kargalin deposits of copper ores, the deposits of the Verkh-Isetsky (Upper Iset) and Kyshtym mining districts, as well as the Mednorudyansk deposit were discovered. | 0 | Metallurgy |
Efficient ribosomal frameshifting generally requires the presence of an RNA secondary structure to enhance the effects of the slippery sequence. The RNA structure (which can be a stem-loop or pseudoknot) is thought to pause the ribosome on the slippery site during translation, forcing it to relocate and continue replication from the −1 position. It is believed that this occurs because the structure physically blocks movement of the ribosome by becoming stuck in the ribosome mRNA tunnel. This model is supported by the fact that strength of the pseudoknot has been positively correlated with the level of frameshifting for associated mRNA.
Below are examples of predicted secondary structures for frameshift elements shown to stimulate frameshifting in a variety of organisms. The majority of the structures shown are stem-loops, with the exception of the ALIL (apical loop-internal loop) pseudoknot structure. In these images, the larger and incomplete circles of mRNA represent linear regions. The secondary "stem-loop" structures, where "stems" are formed by a region of mRNA base pairing with another region on the same strand, are shown protruding from the linear DNA. The linear region of the HIV ribosomal frameshift signal contains a highly conserved UUU UUU A slippery sequence; many of the other predicted structures contain candidates for slippery sequences as well.
The mRNA sequences in the images can be read according to a set of guidelines. While A, T, C, and G represent a particular nucleotide at a position, there are also letters that represent ambiguity which are used when more than one kind of nucleotide could occur at that position. The rules of the International Union of Pure and Applied Chemistry (IUPAC) are as follows:
These symbols are also valid for RNA, except with U (uracil) replacing T (thymine). | 1 | Gene expression + Signal Transduction |
ppGpp inhibits IF2-mediated fMet-Phe initiation dipeptide formation, probably by interfering with 30S and 50S subunit interactions. E. coli accumulates more ppGpp than pppGpp during amino acid starvation, and ppGpp has about 8-fold greater efficiency than that of pppGpp. While B. subtilis accumulates more pppGpp than ppGpp. | 1 | Gene expression + Signal Transduction |
The Schikorr reaction formally describes the conversion of the iron(II) hydroxide (Fe(OH)) into iron(II,III) oxide (FeO). This transformation reaction was first studied by Gerhard Schikorr. The global reaction follows:
It is of special interest in the context of the serpentinization, the formation of hydrogen by the action of water on a common mineral. | 0 | Metallurgy |
Christian Alfred Elie Janot (January 4, 1936 – February 23, 2022) was a French physicist and materials scientist known for his work on materials characterization using Mössbauer spectroscopy and his physical metallurgy studies of quasicrystals and noncrystalline materials using neutron scattering techniques. | 0 | Metallurgy |
The South Turkmenistan Complex Archaeological Expedition (STACE), also called the South Turkmenistan Archaeological Inter-disciplinary Expedition of the Academy of Sciences of the Turkmen Soviet Socialist Republic (YuTAKE) was endorsed by the Turkmenistan Academy of Sciences. It was initially organized by the orientalist Mikhail Evgenievich Masson in 1946. The expedition had several excavations or "Brigades", based on sites and periods, and were spread over many years.
The Chalcolithic settlements of southern Turkmenistan, according to Masson, date to the late 5th millennium – early 3rd millennium BC, as assessed by carbon dating and paleomagnetic studies of the findings from the excavations carried out by STACE in the Altyndepe and Tekkendepe. The foothills of the Kopetdag mountains have revealed the earliest village cultures of Central Asia in the areas of Namazga-Tepe (more than 50 ha) and Altyndepe (26 ha), Ulug Depe (20 ha), Kara Depe (15 ha), and Geok-Syur (12 ha). In 1952, Boris Kuftin, established the basic Chalcolithics to Late Bronze Age sequence based on the excavations carried out at Namazga-Tepe (termed Namazga (NMG) I-VI).
However, the Chalcolithic period ended about 2700 BC due to natural factors of ecology, with the Geok-Syur oasis becoming desertified. This resulted in the migration of people to the ancient delta of the Tedzhen River. This also led to the Early Bronze Age Settlements at Khapuz-depe. | 0 | Metallurgy |
Inositol phosphates are a group of mono- to hexaphosphorylated inositols. Each form of inositol phosphate is distinguished by the number and position of the phosphate group on the inositol ring.
* inositol monophosphate (IP)
* inositol bisphosphate (IP)
* inositol trisphosphate (IP)
* inositol tetrakisphosphate (IP)
* inositol pentakisphosphate (IP)
* inositol hexaphosphate (IP) also known as phytic acid, or phytate (as a salt).
A series of phosphorylation and dephosphorylation reactions are carried out by at least 19 phosphoinositide kinases and 28 phosphoinositide phosphatase enzymes allowing for the inter-conversion between the inositol phosphate compounds based on cellular demand.
Inositol phosphates play a crucial role in various signal transduction pathways responsible for cell growth and differentiation, apoptosis, DNA repair, RNA export, regeneration of ATP and more. | 1 | Gene expression + Signal Transduction |
The advantages of reverse transfection (over conventional transfection) are:
*The addition and attachment of target cells to the DNA-loaded surface can lead to a higher probability of cell-DNA contact, potentially leading to higher transfection efficiency.
*Labour-saving materials (less DNA is required)
*High-throughput screening; hundreds of genes may be expressed in cells on a single microarray for studying gene expression and regulation.
*Parallel cell seeding in a single chamber for 384 experiments, with no physical separation between experiments, increases screening data quality. Well-to-well variations occur in experiments performed in multi-wall dishes.
*Exact-replicate arrays may be produced, since the same sample source plate may be dried and printed on different slides for at least 15 months' storage without apparent loss of transfection efficiency.
The disadvantages of reverse transfection are:
*Reverse transfection is more expensive because a highly accurate and efficient microarray printing system is needed to print the DNA-gelatin solution onto the slides.
*Applications with different cell lines have (so far) required protocol variations to manufacture siRNA or plasmid arrays, which involve considerable development and testing.
*Increased possibility of array-spot cross-contamination as spot density increases; therefore, optimization of the array layout is important. | 1 | Gene expression + Signal Transduction |
The Mission of the International Deep Drawing Research Group ([http://www.iddrg.com IDDRG]) is to co-ordinate research and development work in sheet metal forming, to bring together scientists, researchers and industrialists working on these fields all over the World, to provide open and scientifically highly acknowledged forum to its members to present their research and development findings on all aspects of sheet metal forming and certain related subjects.
The combination of technical presentations and opportunities for discussion are meant to stimulate thinking and to provide valuable interchange of ideas. | 0 | Metallurgy |
OJSC Dolomite () forms part of the Russia metallurgical complex, being the only producer of metallurgical dolomite in the Central Black Earth economic region. The company mines 55% of the total amount of dolomite produced in Russia and 43% in CIS. It is part of the NLMK Group.
The company has explored the Dankov dolomite field (Lipetsk Oblast) since 1932. The product mix includes fluxed and converter dolomite, dolomite flour, crushed rock for construction and road works. The facility is located near to developed transport infrastructure, which is strategically advantageous for its customers.
In 2005 the Company production reached 1.9 mln. tonnes. Dolomite is mainly sold in the domestic market. The main customers are steelmaking companies; their share is 69% of the total sales volume. NLMKs share in the companys sales structure amounted to 51% in 2005. | 0 | Metallurgy |
* Brody, David. Labor in Crisis: The Steel Strike of 1919 (1965)
* Mary Margaret Fonow; Union Women: Forging Feminism in the United Steelworkers of America (University of Minnesota Press, 2003)
* [https://web.archive.org/web/20110717180737/http://www.ussteel.com/corp/about.htm#The%20History%20of%20United%20States%20Steel U.S. Steel's History of U.S. Steel]
* Urofsky, Melvin I. Big Steel and the Wilson Administration: A Study in Business-Government Relations (1969) | 0 | Metallurgy |
Specific mutations in different splice sites in various genes that cause inherited disorders, including, for example, Type 1 diabetes (e.g., PTPN22, TCF1 (HCF-1A)), hypertension (e.g., LDL, LDLR, LPL), Marfan syndrome (e.g., FBN1, TGFBR2, FBN2), cardiac diseases (e.g., COL1A2, MYBPC3, ACTC1), eye disorders (e.g., EVC, VSX1) have been uncovered. A few example mutations in the donor and acceptor splice sites in different genes causing a variety of inherited disorders identified using S&S are shown in Table 2. | 1 | Gene expression + Signal Transduction |
The active zone or synaptic active zone is a term first used by Couteaux and Pecot-Dechavassinein in 1970 to define the site of neurotransmitter release. Two neurons make near contact through structures called synapses allowing them to communicate with each other. As shown in the adjacent diagram, a synapse consists of the presynaptic bouton of one neuron which stores vesicles containing neurotransmitter (uppermost in the picture), and a second, postsynaptic neuron which bears receptors for the neurotransmitter (at the bottom), together with a gap between the two called the synaptic cleft (with synaptic adhesion molecules, SAMs, holding the two together). When an action potential reaches the presynaptic bouton, the contents of the vesicles are released into the synaptic cleft and the released neurotransmitter travels across the cleft to the postsynaptic neuron (the lower structure in the picture) and activates the receptors on the postsynaptic membrane.
The active zone is the region in the presynaptic bouton that mediates neurotransmitter release and is composed of the presynaptic membrane and a dense collection of proteins called the cytomatrix at the active zone (CAZ). The CAZ is seen under the electron microscope to be a dark (electron dense) area close to the membrane. Proteins within the CAZ tether synaptic vesicles to the presynaptic membrane and mediate synaptic vesicle fusion, thereby allowing neurotransmitter to be released reliably and rapidly when an action potential arrives. | 1 | Gene expression + Signal Transduction |
Autoclave reactors are used for reactions at higher temperatures, which can enhance the rate of the reaction. Similarly, autoclaves enable the use of gaseous reagents in the system. | 0 | Metallurgy |
In the early 17th century, ironworkers in Western Europe had developed the cementation process for carburizing wrought iron. Wrought iron bars and charcoal were packed into stone boxes, then sealed with clay to be held at a red heat continually tended in an oxygen-free state immersed in nearly pure carbon (charcoal) for up to a week. During this time, carbon diffused into the surface layers of the iron, producing cement steel or blister steel—also known as case hardened, where the portions wrapped in iron (the pick or axe blade) became harder, than say an axe hammer-head or shaft socket which might be insulated by clay to keep them from the carbon source. The earliest place where this process was used in England was at Coalbrookdale from 1619, where Sir Basil Brooke had two cementation furnaces (recently excavated in 2001–2005). For a time in the 1610s, he owned a patent on the process, but had to surrender this in 1619. He probably used Forest of Dean iron as his raw material, but it was soon found that oregrounds iron was more suitable. The quality of the steel could be improved by faggoting, producing the so-called shear steel. | 0 | Metallurgy |
Concrete cancer may refer to:
* Rebar corrosion and spalling of the concrete cover above rebar caused by the rust expansion and accelerated by chloride attack and pitting corrosion of the steel reinforcements.
* Alkali–silica reaction (ASR), also known as alkali-aggregate reaction (AAR), when reactive amorphous silica aggregates exposed to alkaline conditions (high pH) swell inside the concrete matrix leading to the development of a network of cracks.
It may also refer to:
* Sulfate attacks, an hat appellation covering different concrete degradation mechanisms:
** Delayed ettringite formation (DEF), also known as internal sulfate attack (ISA) when the temperature of fresh concrete exceeds 65 °C during its setting and hardening;
** External sulfate attack (ESA), and;
** Thaumasite form of sulfate attack (TSA). | 0 | Metallurgy |
Given the short sequences of most promoter elements, promoters can rapidly evolve from random sequences. For instance, in E. coli, ~60% of random sequences can evolve expression levels comparable to the wild-type lac promoter with only one mutation, and that ~10% of random sequences can serve as active promoters even without evolution. | 1 | Gene expression + Signal Transduction |
There are several methods that can be used as an alternative to FAIRE-seq. DNase-seq uses the ability of the DNase I enzyme to cleave free/open/accessible DNA to identify and sequence open chromatin. The subsequently developed ATAC-seq employs the Tn5 transposase, which inserts specified fragments or transposons into accessible regions of the genome to identify and sequence open chromatin. | 1 | Gene expression + Signal Transduction |
Oxygen is one of the reagents consumed during cyanidation, accepting the electrons from the gold, and a deficiency in dissolved oxygen slows leaching rate. Air or pure oxygen gas can be purged through the pulp to maximize the dissolved oxygen concentration. Intimate oxygen-pulp contactors are used to increase the partial pressure of the oxygen in contact with the solution, thus raising the dissolved oxygen concentration much higher than the saturation level at atmospheric pressure. Oxygen can also be added by dosing the pulp with hydrogen peroxide solution. | 0 | Metallurgy |
Ferrophosphorus is a ferroalloy, an alloy of iron and phosphorus. It contains high proportion of iron phosphides, FeP and FeP. Its CAS number is 8049-19-2. The usual grades contain either 18 or 25% of phosphorus. It is a gray solid material with melting point between 1050-1100 °C. It may liberate phosphine in contact with water. Very fine powder can be combustible.
Ferrophosphorus is used in metallurgy as a source of phosphorus for alloying, for deoxidizing the melt and for removal of unwanted compounds into slag.
Ferrophosphorus is a byproduct of phosphorus production in submerged-arc furnaces from apatites, by their reduction with carbon. It is formed from the iron oxide impurities.
Addition of ferrophosphorus is used to produce powder metallurgy (P/M) steels with favorable magnetic properties, e.g. high saturation induction. Iron phosphide acts here as a solid solution hardener and a sintering aid. Usually about 0.45 w/o of phosphorus is added to iron; higher amount can improve magnetic properties but at above about 0.8 w/o the process parameters have to be too tightly controlled to prevent phosphorus segregation on grain boundaries and resulting excessive brittleness.
Ferrophosphorus can be added to cast iron, where the phosphorus improves fluidity and therefore quality of the castings, can increase wear resistance and cutability. In steels its addition to some alloys can improve corrosion resistance.
Ferrophosphorus can be used as a construction aggregate for production of high-density concrete for radiation shielding, as an alternative to usually used steel punchings and shot. It can be used with both Portland cement and magnesia cement.
Ferrophosphorus, reacted with sulfur or pyrite, is used for production of phosphorus pentasulfide.
Ferrophosphorus can be used for production of lithium iron phosphate, necessary as electrode material for LiFePO4 batteries.
Ferrophosphorus can be used instead of zinc powder in some paints and coatings. It has good adhesion, anticorrosive properties, electrical and thermal conductivity, and wear resistance.
Ferrophosphorus can be used as a reducing agent to produce sodium or potassium from sodium carbonate or potassium carbonate. | 0 | Metallurgy |
Grain boundary engineering involves manipulating the grain boundary structure and energy to enhance mechanical properties. By controlling the interfacial energy, it is possible to engineer materials with desirable grain boundary characteristics, such as increased interfacial area, higher grain boundary density, or specific grain boundary types.
* Alloying
Introducing alloying elements into the material can alter the interfacial energy of grain boundaries. Alloying can result in segregation of solute atoms at the grain boundaries, which can modify the atomic arrangements and bonding, and thereby influence the interfacial energy.
* Surface Treatments and Coatings
Applying surface treatments or coatings can modify the interfacial energy of grain boundaries. Surface modification techniques, such as chemical treatments or deposition of thin films, can alter the surface energy and consequently affect the grain boundary energy.
* Heat Treatments and Annealing
Thermal treatments can be employed to modify the interfacial energy of grain boundaries. Annealing at specific temperatures and durations can induce atomic rearrangements, diffusion, and stress relaxation at the grain boundaries, leading to changes in the interfacial energy.
Once the interfacial energy is controlled, grain boundaries can be manipulated to enhance their strengthening effects.
* Severe Plastic Deformation
Applying severe plastic deformation techniques, such as equal-channel angular pressing (ECAP) or high-pressure torsion (HPT), can lead to grain refinement and the creation of new grain boundaries with tailored characteristics. These refined grain structures can exhibit a high density of grain boundaries, including high-angle boundaries, which can contribute to enhanced grain boundary strengthening.
* Thermomechanical Processing
Utilizing specific thermomechanical processing routes, such as rolling, forging, or extrusion, can result in the creation of a desired texture and the development of specific grain boundary structures. These processing routes can promote the formation of specific grain boundary types and orientations, leading to improved grain boundary strengthening. | 0 | Metallurgy |
Adam17 may facilitate entry of the SARS‑CoV‑2 virus, possibly by enabling fusion of virus particles with the cytoplasmic membrane. Adam17 has similar ACE2 cleavage activity as TMPRSS2, but by forming soluble ACE2, Adam17 may actually have the protective effect of blocking circulating SARS‑CoV‑2 virus particles.
Adam17 sheddase activity may contribute to COVID-19 inflammation by cleavage of TNF-α and Interleukin-6 receptor. | 1 | Gene expression + Signal Transduction |
Ribozymes are catalytic RNA molecules used to inhibit gene expression. These molecules work by cleaving mRNA molecules, essentially silencing the genes that produced them. Sidney Altman and Thomas Cech first discovered catalytic RNA molecules, RNase P and group II intron ribozymes, in 1989 and won the Nobel Prize for their discovery. Several types of ribozyme motifs exist, including hammerhead, hairpin, hepatitis delta virus, group I, group II, and RNase P ribozymes. Hammerhead, hairpin, and hepatitis delta virus (HDV) ribozyme motifs are generally found in viruses or viroid RNAs. These motifs are able to self-cleave a specific phosphodiester bond on an mRNA molecule. Lower eukaryotes and a few bacteria contain group I and group II ribozymes. These motifs can self-splice by cleaving and joining phosphodiester bonds. The last ribozyme motif, the RNase P ribozyme, is found in Escherichia coli and is known for its ability to cleave the phosphodiester bonds of several tRNA precursors when joined to a protein cofactor.
The general catalytic mechanism used by ribozymes is similar to the mechanism used by protein ribonucleases. These catalytic RNA molecules bind to a specific site and attack the neighboring phosphate in the RNA backbone with their 2 oxygen, which acts as a nucleophile, resulting in the formation of cleaved products with a 23-cyclic phosphate and a 5 hydroxyl terminal end. This catalytic mechanism has been increasingly used by scientists to perform sequence-specific cleavage of target mRNA molecules. In addition, attempts are being made to use ribozymes to produce gene silencing therapeutics, which would silence genes that are responsible for causing diseases. | 1 | Gene expression + Signal Transduction |
The term co-receptor is prominent in literature regarding signal transduction, the process by which external stimuli regulate internal cellular functioning. The key to optimal cellular functioning is maintained by possessing specific machinery that can carry out tasks efficiently and effectively. Specifically, the process through which intermolecular reactions forward and amplify extracellular signals across the cell surface has developed to occur by two mechanisms.
First, cell surface receptors can directly transduce signals by possessing both serine and threonine or simply serine in the cytoplasmic domain. They can also transmit signals through adaptor molecules through their cytoplasmic domain which bind to signalling motifs. Secondly, certain surface receptors lacking a cytoplasmic domain can transduce signals through ligand binding. Once the surface receptor binds the ligand it forms a complex with a corresponding surface receptor to regulate signalling. These categories of cell surface receptors are prominently referred to as co-receptors. Co-receptors are also referred to as accessory receptors, especially in the fields of biomedical research and immunology.
Co-receptors are proteins that maintain a three-dimensional structure. The large extracellular domains make up approximately 76–100% of the receptor. The motifs that make up the large extracellular domains participate in ligand binding and complex formation.
The motifs can include glycosaminoglycans, EGF repeats, cysteine residues or ZP-1 domains. The variety of motifs leads to co-receptors being able to interact with two to nine different ligands, which themselves can also interact with a number of different co-receptors.
Most co-receptors lack a cytoplasmic domain and tend to be GPI-anchored, though a few receptors have been identified which contain short cytoplasmic domains that lack intrinsic kinase activity. | 1 | Gene expression + Signal Transduction |
The purification process utilizes the cementation process to further purify the zinc. It uses zinc dust and steam to remove copper, cadmium, cobalt, and nickel, which would interfere with the electrolysis process. After purification, concentrations of these impurities are limited to less than 0.05 milligram per liter (4×10 pound per U.S. gallon). Purification is usually conducted in large agitated tanks. The process takes place at temperatures ranging from , and pressures ranging from atmospheric to (absolute scale). The by-products are sold for further refining.
The zinc sulfate solution must be very pure for electrowinning to be at all efficient. Impurities can change the decomposition voltage enough to where the electrolysis cell produces largely hydrogen gas rather than zinc metal. | 0 | Metallurgy |
ROP proteins are a type of monomeric G proteins found in plants belonging to the Rho family. ROP binding to GTP or GDP determines its activity due to conformational changes within its structure. Within the G-domain of the structure are the G-box motifs G1-5. These motifs are formed during protein folding and are composed of conserved sequences that are responsible for nucleotide and magnesium binding as well as hydrolysis of GTP. Motifs G2 (switch I loop) and G3 (switch II loop) possess distinct conformations depending on GTP binding state. In addition, the G-domain contains a unique and conserved helical domain commonly found in Rho family proteins called αi.
Specific locations within the 3D ROP protein structure, including the amino acids 13-20, 60-64, and 118-121, act as binding sites during protein activity. The serine residue at amino acid 74 has been shown to be a potential protein activity regulation site through phosphorylation. | 1 | Gene expression + Signal Transduction |
The practice of using colours to determine the temperature of a piece of (usually) ferrous metal comes from blacksmithing. Long before thermometers were widely available, it was necessary to know what state the metal was in for heat treating it and the only way to do this was to heat it up to a colour which was known to be best for the work. | 0 | Metallurgy |
RPB3 is involved in RNA polymerase II assembly. A subcomplex of RPB2 and RPB3 appears soon after subunit synthesis. This complex subsequently interacts with RPB1. RPB3, RPB5, and RPB7 interact with themselves to form homodimers, and RPB3 and RPB5 together are able to contact all of the other RPB subunits, except RPB9. Only RPB1 strongly binds to RPB5. The RPB1 subunit also contacts RPB7, RPB10, and more weakly but most efficiently with RPB8. Once RPB1 enters the complex, other subunits such as RPB5 and RPB7 can enter, where RPB5 binds to RPB6 and RPB8 and RPB3 brings in RPB10, RPB 11, and RPB12. RPB4 and RPB9 may enter once most of the complex is assembled. RPB4 forms a complex with RPB7. | 1 | Gene expression + Signal Transduction |
The exact temperatures at which iron will transition from one crystal structure to another depends on how much and what type of other elements are dissolved in the iron. The phase boundary between the different solid phases is drawn on a binary phase diagram, usually plotted as temperature versus percent iron. Adding some elements, such as Chromium, narrows the temperature range for the gamma phase, while others increase the temperature range of the gamma phase. In elements that reduce the gamma phase range, the alpha-gamma phase boundary connects with the gamma-delta phase boundary, forming what is usually called the Gamma loop. Adding Gamma loop additives keeps the iron in a body-centered cubic structure and prevents the steel from suffering phase transition to other solid states. | 0 | Metallurgy |
The core was probably originally compiled around AD 600, perhaps in Alexandria in Egypt, in Greek. The core contains items traceable to earlier Alexandrian Greek texts, particularly the Stockholm papyrus and Leiden Papyrus X, which are Greek texts dated to the 2nd or 3rd century AD that contain some of the same and similar recipes. The first few recipes in the Phillipps-Corning manuscript of the Mappae clavicula were long considered integral, but they form a distinct separate entity, the De coloribus et mixtionibus, which survives (in whole or in part) in at least 62 manuscripts. The core of the Latin Mappae clavicula is very likely a translation of a Greek text, although the original Greek text (if it existed) does not exist today.
The best manuscripts of the Mappae clavicula date from the eighth to the twelfth century.
One of the fullest collections of recipes is in a certain manuscript dated late 12th century in which about 300 recipes are presented. In this manuscript, called the Phillipps-Corning manuscript, some of the names for some materials are Arabic names (e.g. alquibriz from the Arabic for sulphur, atincar from the Arabic for borax, alcazir from the Arabic for tin). The recipes containing the Arabic names are historically later, and are in all likelihood no earlier than the 12th century. Certain earlier manuscripts have about 200 recipes. | 0 | Metallurgy |
FK phase materials have been pointed out for their high-temperature structure and as superconducting materials. Their complex and often non-stoichiometric structure makes them good subjects for theoretical calculations.
A15, Laves and σ are the most applicable FK structures with interesting fundamental properties.
The A15 compounds include important intermetallic superconductors such as: NbSn, NbAl, and VGa with applications including wires for high-field superconducting magnets. NbSn is also being investigated as a potential material for fabricating superconducting radio frequency cavities.
Small extents of σ phase considerably decreases the flexibility and impairment in erosion resistance. While addition of refractory elements like W, Mo, or Re to FK phases helps to enhance the thermal properties in such alloys as steels or nickel-based superalloys, it increases the risk of unwanted precipitation in intermetallic compounds. | 0 | Metallurgy |
Organic chemicals such as lactic acid and citric acid have been used to etch metals and create products as early as 400 BCE, when vinegar was used to corrode lead and create the pigment ceruse, also known as white lead. Most modern chemical milling methods involve alkaline etchants; these may have been used as early as the first century CE.
Armor etching, using strong mineral acids, was not developed until the fifteenth century. Etchants mixed from salt, charcoal, and vinegar were applied to plate armor that had been painted with a maskant of linseed-oil paint. The etchant would bite into the unprotected areas, causing the painted areas to be raised into relief. Etching in this manner allowed armor to be decorated as if with precise engraving, but without the existence of raised burrs; it also prevented the necessity of the armor being softer than an engraving tool. Late in the seventeenth century, etching became used to produce the graduations on measuring instruments; the thinness of lines that etching could produce allowed for the production of more precise and accurate instruments than were possible before. Not long after, it became used to etch trajectory information plates for cannon and artillery operators; paper would rarely survive the rigors of combat, but an etched plate could be quite durable. Often such information (normally ranging marks) was etched onto equipment such as stiletto daggers or shovels.
In 1782, the discovery was made by John Senebier that certain resins lost their solubility to turpentine when exposed to light; that is, they hardened. This allowed the development of photochemical milling, where a liquid maskant is applied to the entire surface of a material, and the outline of the area to be masked created by exposing it to UV light. Photo-chemical milling was extensively used in the development of photography methods, allowing light to create impressions on metal plates.
One of the earliest uses of chemical etching to mill commercial parts was in 1927, when the Swedish company Aktiebolaget Separator patented a method of producing edge filters by chemically milling the gaps in the filters. Later, around the 1940s, it became widely used to machine thin samples of very hard metal; photo-etching from both sides was used to cut sheet metal, foil, and shim stock to create shims, recording heat frets, and other components. | 0 | Metallurgy |
The first reported steps towards the discovery of the shape-memory effect were taken in the 1930s. According to Otsuka and Wayman, Arne Ölander discovered the pseudoelastic behavior of the Au-Cd alloy in 1932. Greninger and Mooradian (1938) observed the formation and disappearance of a martensitic phase by decreasing and increasing the temperature of a Cu-Zn alloy. The basic phenomenon of the memory effect governed by the thermoelastic behavior of the martensite phase was widely reported a decade later by Kurdjumov and Khandros (1949) and also by Chang and Read (1951).
The nickel-titanium alloys were first developed in 1962–1963 by the United States Naval Ordnance Laboratory and commercialized under the trade name Nitinol (an acronym for Nickel Titanium Naval Ordnance Laboratories). Their remarkable properties were discovered by accident. A sample that was bent out of shape many times was presented at a laboratory management meeting. One of the associate technical directors, Dr. David S. Muzzey, decided to see what would happen if the sample was subjected to heat and held his pipe lighter underneath it. To everyone's amazement the sample stretched back to its original shape.
There is another type of SMA, called a ferromagnetic shape-memory alloy (FSMA), that changes shape under strong magnetic fields. These materials are of particular interest as the magnetic response tends to be faster and more efficient than temperature-induced responses.
Metal alloys are not the only thermally-responsive materials; shape-memory polymers have also been developed, and became commercially available in the late 1990s. | 0 | Metallurgy |
Currently, the stability of most ionic liquids under practical electrochemical conditions is unknown, and the fundamental choice of ionic fluid is still empirical as there is almost no data on metal ion thermodynamics to feed into solubility and speciation models. Also, there are no Pourbaix diagrams available, no standard redox potentials, and bare knowledge of speciation or pH-values. It must be noticed that most processes reported in the literature involving ionic fluids have a Technology Readiness Level (TRL) 3 (experimental proof-of-concept) or 4 (technology validated in the lab), which is a disadvantage for short-term implementation. However, ionometallurgy has the potential to effectively recover metals in a more selective and sustainable way, as it considers environmentally benign solvents, reduction of greenhouse gas emissions and avoidance of corrosive and harmful reagents. | 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), Valine (Val, V). | 1 | Gene expression + Signal Transduction |
Due to its ease of operation and its usefulness in polishing irregularly-shaped objects, electropolishing has become a common process in the production of semiconductors.
As electropolishing can also be used to sterilize workpieces, the process plays an essential role in the food, medical, and pharmaceutical industries.
It is commonly used in the post-production of large metal pieces such as those used in drums of washing machines, bodies of ocean vessels and aircraft, and automobiles.
While nearly any metal may be electropolished, the most-commonly polished metals are 300- and 400-series stainless steel, aluminum, copper, titanium, and nickel- and copper-alloys.
Ultra-high vacuum (UHV) components are typically electropolished in order to have a smoother surface for improved vacuum pressures, out-gassing rates, and pumping speed.
Electropolishing is commonly used to prepare thin metal samples for transmission electron microscopy and atom probe tomography because the process does not mechanically deform surface layers like mechanical polishing does. | 0 | Metallurgy |
Hormone producing cells are found in the endocrine glands, such as the thyroid gland, ovaries, and testes. Hormonal signaling involves the following steps:
# Biosynthesis of a particular hormone in a particular tissue.
# Storage and secretion of the hormone.
# Transport of the hormone to the target cell(s).
# Recognition of the hormone by an associated cell membrane or intracellular receptor protein.
# Relay and amplification of the received hormonal signal via a signal transduction process: This then leads to a cellular response. The reaction of the target cells may then be recognized by the original hormone-producing cells, leading to a downregulation in hormone production. This is an example of a homeostatic negative feedback loop.
# Breakdown of the hormone.
Exocytosis and other methods of membrane transport are used to secrete hormones when the endocrine glands are signaled. The hierarchical model is an oversimplification of the hormonal signaling process. Cellular recipients of a particular hormonal signal may be one of several cell types that reside within a number of different tissues, as is the case for insulin, which triggers a diverse range of systemic physiological effects. Different tissue types may also respond differently to the same hormonal signal. | 1 | Gene expression + Signal Transduction |
A salamander (or deadman's foot or furnace bear) in the metallurgy dialect means all liquid and solidified
materials in the hearth of a blast furnace below the tap hole.
The target of the salamander tapping is to remove the remaining hot metal and slag from the blast furnace to allow a safe and efficient intermediate repair and blow-in of the blast furnace.
During blowing down of the furnace the salamander is tapped by drilling a hole in the blast furnace hearth. | 0 | Metallurgy |
The method is similar to the cyanide method above, except sulfuric acid is used to dissolve copper from its ores. The acid is recycled from the solvent extraction circuit (see solvent extraction-electrowinning, SX/EW) and reused on the leach pad. A byproduct is iron(II) sulfate, jarosite, which is produced as a byproduct of leaching pyrite, and sometimes even the same sulfuric acid that is needed for the process. Both oxide and sulfide ores can be leached, though the leach cycles are much different and sulfide leaching requires a bacterial, or bio-leach, component.
In 2011 leaching, both heap leaching and in-situ leaching, produced 3.4 million metric tons of copper, 22 percent of world production. The largest copper heap leach operations are in Chile, Peru, and the southwestern United States.
Although heap leaching is a low cost-process, it normally has recovery rates of 60-70%. It is normally most profitable with low-grade ores. Higher-grade ores are usually put through more complex milling processes where higher recoveries justify the extra cost. The process chosen depends on the properties of the ore.
The final product is cathode copper. | 0 | Metallurgy |
A similar-looking kind of damage is called false brinelling and is caused by fretting wear. Fretting wear occurs when localized wear-marks develop in evenly spaced patterns, with raised or unworn portions in between, like frets on a guitar. False brinelling occurs in two types: stationary and by precession.
Stationary false-brinelling occurs without any rotational motion in the bearing. This occurs when contacting bodies vibrate against each other in the presence of very small loads, which pushes lubricant out of the contact surface area, all while the bearing assembly cannot move far enough (or rotate far enough) to redistribute the displaced lubricant. The result is a finely polished surface that resembles a brinell mark, but has not permanently deformed either contacting surface. This type of false brinelling usually occurs in bearings during transportation, between the time of manufacture and installation. The polished surfaces are often mistaken for brinelling, although no actual damage to the bearing exists. The false brinelling will disappear after a short break-in period of operation.
Fretting wear can also occur during operation, causing deep indentations. This occurs when small vibrations form in the rotating shaft and become harmonically in sync with the speed of rotation, causing circular oscillations in the shaft. The oscillation causes the shaft to move in precession, and the timing of the rotation speed causes the balls or rollers to contact the races only when they are in similar positions. This forms wear marks caused by contact with the bearings and the races in specific areas, but not in others, leaving an uneven wear-pattern that can become quite deep before failure occurs, resembling brinelling. However, the marks are usually too wide, due to the motion of the bearing, and do not exactly match the shape of the rolling elements, and therefore this type of wear can be differentiated from true brinelling. | 0 | Metallurgy |
Hazardous materials are often carried in pipelines and thus their structural integrity is of paramount importance. Corrosion of a pipeline can thus have grave consequences. One of the methods used to control pipeline corrosion is by the use of Fusion bonded epoxy coatings. DCVG is used to monitor it. Impressed current cathodic protection is also used. | 0 | Metallurgy |
*Monocytes / macrophages: the key chemokines that attract these cells to the site of inflammation include: CCL2, CCL3, CCL5, CCL7, CCL8, CCL13, CCL17 and CCL22.
*T-lymphocytes: the four key chemokines that are involved in the recruitment of T lymphocytes to the site of inflammation are: CCL2, CCL1, CCL22 and CCL17. Furthermore, CXCR3 expression by T-cells is induced following T-cell activation and activated T-cells are attracted to sites of inflammation where the IFN-y inducible chemokines CXCL9, CXCL10 and CXCL11 are secreted.
*Mast cells: on their surface express several receptors for chemokines: CCR1, CCR2, CCR3, CCR4, CCR5, CXCR2, and CXCR4. Ligands of these receptors CCL2 and CCL5 play an important role in mast cell recruitment and activation in the lung. There is also evidence that CXCL8 might be inhibitory of mast cells.
*Eosinophils: the migration of eosinophils into various tissues involved several chemokines of CC family: CCL11, CCL24, CCL26, CCL5, CCL7, CCL13, and CCL3. Chemokines CCL11 (eotaxin) and CCL5 (RANTES) acts through a specific receptor CCR3 on the surface of eosinophils, and eotaxin plays an essential role in the initial recruitment of eosinophils into the lesion.
*Neutrophils: are regulated primarily by CXC chemokines. An example CXCL8 (IL-8) is chemoattractant for neutrophils and also activating their metabolic and degranulation. | 1 | Gene expression + Signal Transduction |
PGC-1α is thought to be a master integrator of external signals. It is known to be activated by a host of factors, including:
# Reactive oxygen species and reactive nitrogen species, both formed endogenously in the cell as by-products of metabolism but upregulated during times of cellular stress.
#Fasting can also increase gluconeogenic gene expression, including hepatic PGC-1α.
# It is strongly induced by cold exposure, linking this environmental stimulus to adaptive thermogenesis.
# It is induced by endurance exercise and recent research has shown that PGC-1α determines lactate metabolism, thus preventing high lactate levels in endurance athletes and making lactate as an energy source more efficient.
# cAMP response element-binding (CREB) proteins, activated by an increase in cAMP following external cellular signals.
# Protein kinase B (Akt) is thought to downregulate PGC-1α, but upregulate its downstream effectors, NRF1 and NRF2. Akt itself is activated by PIP, often upregulated by PI3K after G protein signals. The Akt family is also known to activate pro-survival signals as well as metabolic activation.
# SIRT1 binds and activates PGC-1α through deacetylation inducing gluconeogenesis without affecting mitochondrial biogenesis.
PGC-1α has been shown to exert positive feedback circuits on some of its upstream regulators:
# PGC-1α increases Akt (PKB) and Phospho-Akt (Ser 473 and Thr 308) levels in muscle.
# PGC-1α leads to calcineurin activation.
Akt and calcineurin are both activators of NF-kappa-B (p65). Through their activation, PGC-1α seems to activate NF-kappa-B. Increased activity of NF-kappa-B in muscle has recently been demonstrated following induction of PGC-1α. The finding seems to be controversial. Other groups found that PGC-1s inhibit NF-kappa-B activity. The effect was demonstrated for PGC-1 alpha and beta.
PGC-1α has also been shown to drive NAD biosynthesis to play a large role in renal protection in acute kidney injury. | 1 | Gene expression + Signal Transduction |
In orthodox two-component signaling, a histidine kinase protein autophosphorylates on a histidine residue in response to an extracellular signal, and the phosphoryl group is subsequently transferred to an aspartate residue on the receiver domain of a response regulator. In phosphorelays, the "hybrid" histidine kinase contains an internal aspartate-containing receiver domain to which the phosphoryl group is transferred, after which an HPt protein containing a phosphorylatable histidine receives the phosphoryl group and finally transfers it to the response regulator. The relay system thus progresses in the order His-Asp-His-Asp, with the second His contributed by Hpt. In some cases, a phosphorelay system is constructed from four separate proteins rather than a hybrid histidine kinase with an internal receiver domain, and in other examples both the receiver and the HPt domains are present in the histidine kinase polypeptide chain. A census of two-component system domain architecture found that HPt domains in bacteria are more common as domains of larger proteins than they are as individual proteins. | 1 | Gene expression + Signal Transduction |
Bacterial initiation factor-2 is a bacterial initiation factor.
IF2 binds to an initiator tRNA and controls the entry of tRNA onto the ribosome. IF2, bound to GTP, binds to the 30S P site. After associating with the 30S subunit, fMet-tRNA binds to the IF2 then IF2 transfers the tRNA into the partial P site. When the 50S subunit joins, it hydrolyzes GTP to GDP and P, causing a conformational change in the IF2 that causes IF2 to release and allow the 70S ribosome to form.
Human mitochondria use a nuclear-encoded homolog, MTIF2, for translation initiation. | 1 | Gene expression + Signal Transduction |
The proper identification of splice sites has to be highly precise as the consensus splice sequences are very short and there are many other sequences similar to the authentic splice sites within gene sequences, which are known as cryptic, non-canonical, or pseudo splice sites. When an authentic or real splice site is mutated, any cryptic splice sites present close to the original real splice site could be erroneously used as authentic site, resulting in an aberrant mRNA. The erroneous mRNA may include a partial sequence from the neighboring intron or lose a partial exon, which may result in a premature stop codon. The result may be a truncated protein that would have lost its function completely.
Shapiro–Senapathy algorithm can identify the cryptic splice sites, in addition to the authentic splice sites. Cryptic sites can often be stronger than the authentic sites, with a higher S&S score. However, due to the lack of an accompanying complementary donor or acceptor site, this cryptic site will not be active or used in a splicing reaction. When a neighboring real site is mutated to become weaker than the cryptic site, then the cryptic site may be used instead of the real site, resulting in a cryptic exon and an aberrant transcript.
Numerous diseases have been caused by cryptic splice site mutations or usage of cryptic splice sites due to the mutations in authentic splice sites. | 1 | Gene expression + Signal Transduction |
Homologous recombination is the exchange of genes between two DNA strands that include extensive regions of base sequences that are identical to one another. In eukaryotic species, bacteria, and some viruses, homologous recombination happens spontaneously and is a useful tool in genetically engineered. Homologous recombination, which takes place during meiosis in eukaryotes, is essential for the repair of double-stranded DNA breaks and promotes genetic variation by allowing the movement of genetic information during chromosomal crossing. Homologous recombination, a key DNA repair mechanism in bacteria, enables the insertion of genetic material acquired through horizontal transfer of genes and transformation into DNA. Homologous recombination in viruses influences the course of viral evolution. Homologous recombination, a type of gene targeting used in genetic engineering, involves the introduction of an engineered mutation into a particular gene in order to learn more about the function of that gene. This method involves inserting foreign DNA into a cell that has a sequence similar to the target gene while being flanked by sequences that are the same upstream and downstream of the target gene. The target genes DNA is substituted with the foreign DNA sequence during replication when the cell detects the similar flanking regions as homologues. The target gene is "knocked out" by the exchange. By using this technique to target particular alleles in embryonic stem cells in mice, it is possible to create knockout mice. With the aid of gene targeting, numerous mouse genes have been shut down, leading to the creation of hundreds of distinct mouse models of various human diseases, such as cancer, diabetes, cardiovascular diseases, and neurological disorders. Mario Capecchi, Sir Martin J. Evans, and Oliver Smithies performed groundbreaking research on homologous recombination in mouse stem cells, and they shared the 2007 Nobel Prize in Physiology or Medicine for their findings. Traditionally, homologous recombination was the main method for causing a gene knockout. This method involves creating a DNA construct containing the desired mutation. For knockout purposes, this typically involves a drug resistance marker in place of the desired knockout gene. The construct will also contain a minimum of 2kb of homology to the target sequence. The construct can be delivered to stem cells either through microinjection or electroporation. This method then relies on the cells own repair mechanisms to recombine the DNA construct into the existing DNA. This results in the sequence of the gene being altered, and most cases the gene will be translated into a nonfunctional protein, if it is translated at all. However, this is an inefficient process, as homologous recombination accounts for only 10 to 10 of DNA integrations. Often, the drug selection marker on the construct is used to select for cells in which the recombination event has occurred.
These stem cells now lacking the gene could be used in vivo, for instance in mice, by inserting them into early embryos. If the resulting chimeric mouse contained the genetic change in their germline, this could then be passed on offspring.
In diploid organisms, which contain two alleles for most genes, and may as well contain several related genes that collaborate in the same role, additional rounds of transformation and selection are performed until every targeted gene is knocked out. Selective breeding may be required to produce homozygous knockout animals. | 1 | Gene expression + Signal Transduction |
Fulmer Research Institute was founded in 1945 as a UK contract research and development organization specializing in materials technology and related areas of physics and chemistry. It was modelled on American contract research companies such as Battelle Memorial Institute and The Mellon Institute of Industrial Research. In 1965 it was acquired by The Institute of Physics and the Physical Society, a rare case of a contract research company being owned by a Learned Society. Through the 1970s and 80s Fulmer evolved. Its services in testing, consultancy and certification were greatly strengthened while academic research declined. It continued to make important developments and innovations for industry and government until in 1990 it was split up and sold to other R & D and testing organizations.
A few of the landmark achievements during its forty five years were:
* The extraction of aluminium using sub-halide sublimation
* Aluminium-tin and aluminium-lead alloys for plain-bearings
* Chemical Vapour Deposition of metals and ceramics to produce coatings, tubes, crucibles etc.
* Fundamental research into aluminium copper alloys, leading to high strength formulations for the skin of high performance aircraft
* YQAF, a subsidiary company authorised to assess and accredit organizations to quality standards.
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Hellmut Friedrich Fischmeister (14 May 1927 – 6 November 2019) was an Austrian metallurgist who was a pioneer in powder metallurgy. | 0 | Metallurgy |
In resting cells, axin molecules oligomerize with each other through their C-terminal DIX domains, which have two binding interfaces. Thus they can build linear oligomers or even polymers inside the cytoplasm of cells. DIX domains are unique: the only other proteins known to have a DIX domain are Dishevelled and DIXDC1. (The single Dsh protein of Drosophila corresponds to three paralogous genes, Dvl1, Dvl2 and Dvl3 in mammals.) Dsh associates with the cytoplasmic regions of Frizzled receptors with its PDZ and DEP domains. When a Wnt molecule binds to Frizzled, it induces a poorly known cascade of events, that result in the exposure of dishevelleds DIX domain and the creation of a perfect binding site for axin. Axin is then titrated away from its oligomeric assemblies – the β-catenin destruction complex – by Dsh. Once bound to the receptor complex, axin will be rendered incompetent for β-catenin binding and GSK3 activity. Importantly, the cytoplasmic segments of the Frizzled-associated LRP5 and LRP6 proteins contain GSK3 pseudo-substrate sequences (Pro-Pro-Pro-Ser-Pro-x-Ser), appropriately "primed" (pre-phosphorylated) by CKI, as if it were a true substrate of GSK3. These false target sites greatly inhibit GSK3 activity in a competitive manner. This way receptor-bound axin will abolish mediating the phosphorylation of β-catenin. Since β-catenin is no longer marked for destruction, but continues to be produced, its concentration will increase. Once β-catenin levels rise high enough to saturate all binding sites in the cytoplasm, it will also translocate into the nucleus. Upon engaging the transcription factors LEF1, TCF1, TCF2 or TCF3, β-catenin forces them to disengage their previous partners: Groucho proteins. Unlike Groucho', that recruit transcriptional repressors (e.g. histone-lysine methyltransferases), β-catenin will bind transcriptional activators, switching on target genes. | 1 | Gene expression + Signal Transduction |
* Bacteriophytochrome
* sensory bacteriorhodopsin
* Halorhodopsin
* Proteorhodopsin
* Cyanobacteriochrome | 1 | Gene expression + Signal Transduction |
Galaxy IV was a telecommunications satellite that was disabled and lost due to short circuits caused by tin whiskers in 1998. It was initially thought that space weather contributed to the failure, but later it was discovered that a conformal coating had been misapplied, allowing whiskers formed in the pure tin plating to find their way through a missing coating area, causing a failure of the main control computer. The manufacturer, Hughes, has moved to nickel plating, rather than tin, to reduce the risk of whisker growth. The trade-off has been an increase in weight, adding per payload. | 0 | Metallurgy |
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist. Antagonist drugs interfere in the natural operation of receptor proteins. They are sometimes called blockers; examples include alpha blockers, beta blockers, and calcium channel blockers. In pharmacology, antagonists have affinity but no efficacy for their cognate receptors, and binding will disrupt the interaction and inhibit the function of an agonist or inverse agonist at receptors. Antagonists mediate their effects by binding to the active site or to the allosteric site on a receptor, or they may interact at unique binding sites not normally involved in the biological regulation of the receptor's activity. Antagonist activity may be reversible or irreversible depending on the longevity of the antagonist–receptor complex, which, in turn, depends on the nature of antagonist–receptor binding. The majority of drug antagonists achieve their potency by competing with endogenous ligands or substrates at structurally defined binding sites on receptors. | 1 | Gene expression + Signal Transduction |
A gene (or genetic) regulatory network (GRN) is a collection of molecular regulators that interact with each other and with other substances in the cell to govern the gene expression levels of mRNA and proteins which, in turn, determine the function of the cell. GRN also play a central role in morphogenesis, the creation of body structures, which in turn is central to evolutionary developmental biology (evo-devo).
The regulator can be DNA, RNA, protein or any combination of two or more of these three that form a complex, such as a specific sequence of DNA and a transcription factor to activate that sequence. The interaction can be direct or indirect (through transcribed RNA or translated protein). In general, each mRNA molecule goes on to make a specific protein (or set of proteins). In some cases this protein will be structural, and will accumulate at the cell membrane or within the cell to give it particular structural properties. In other cases the protein will be an enzyme, i.e., a micro-machine that catalyses a certain reaction, such as the breakdown of a food source or toxin. Some proteins though serve only to activate other genes, and these are the transcription factors that are the main players in regulatory networks or cascades. By binding to the promoter region at the start of other genes they turn them on, initiating the production of another protein, and so on. Some transcription factors are inhibitory.
In single-celled organisms, regulatory networks respond to the external environment, optimising the cell at a given time for survival in this environment. Thus a yeast cell, finding itself in a sugar solution, will turn on genes to make enzymes that process the sugar to alcohol. This process, which we associate with wine-making, is how the yeast cell makes its living, gaining energy to multiply, which under normal circumstances would enhance its survival prospects.
In multicellular animals the same principle has been put in the service of gene cascades that control body-shape. Each time a cell divides, two cells result which, although they contain the same genome in full, can differ in which genes are turned on and making proteins. Sometimes a self-sustaining feedback loop ensures that a cell maintains its identity and passes it on. Less understood is the mechanism of epigenetics by which chromatin modification may provide cellular memory by blocking or allowing transcription. A major feature of multicellular animals is the use of morphogen gradients, which in effect provide a positioning system that tells a cell where in the body it is, and hence what sort of cell to become. A gene that is turned on in one cell may make a product that leaves the cell and diffuses through adjacent cells, entering them and turning on genes only when it is present above a certain threshold level. These cells are thus induced into a new fate, and may even generate other morphogens that signal back to the original cell. Over longer distances morphogens may use the active process of signal transduction. Such signalling controls embryogenesis, the building of a body plan from scratch through a series of sequential steps. They also control and maintain adult bodies through feedback processes, and the loss of such feedback because of a mutation can be responsible for the cell proliferation that is seen in cancer. In parallel with this process of building structure, the gene cascade turns on genes that make structural proteins that give each cell the physical properties it needs. | 1 | Gene expression + Signal Transduction |
A second major group of British bun ingots date to the Roman period and are found mostly in the copper-rich highland areas of Wales and in Scotland. They are heavier than the LBA examples, with weights ranging between 12 and 22 kg.
Some have stamps clearly dating them to the Roman period including an example that reads SOCIO ROMAE NATSOL. The term "socio" suggests that the ingots were cast by a private company rather than by the state. Fraser Hunter reassessed the context of the Scottish examples and some of the unstamped Welsh examples and argues that they could in fact date to the Iron Age or at least reflect native rather than Roman copper working. Although ingots of any sort are not common in the British Iron Age, planoconvex or bun-shaped ingots exist, e.g. a tin ingot discovered within the Iron Age hillfort at Chun Castle, Cornwall. | 0 | Metallurgy |
In a cascade mediated by a GPCR known as β adrenoceptor, activated by catecholamines (notably norepinephrine), PKA gets activated and phosphorylates numerous targets, namely: L-type calcium channels, phospholamban, troponin I, myosin binding protein C, and potassium channels. This increases inotropy as well as lusitropy, increasing contraction force as well as enabling the muscles to relax faster. | 1 | Gene expression + Signal Transduction |
The idea that there must be specific transport proteins associated with the uptake of monoamines and acetylcholine into vesicles developed due to the discovery of specific inhibitors which interfered with monoamine neurotransmission and also depleted monoamines in neuroendocrine tissues. VMAT1 and VMAT2 were first identified in rats upon cloning cDNAs for proteins which gave non-amine accumulating recipient cells the ability to sequester monoamines. Subsequently, human VMATs were cloned using human cDNA libraries with the rat homologs as probes, and heterologous-cell amine uptake assays were performed to verify transport properties. | 1 | Gene expression + Signal Transduction |
An important disadvantage of polycrystalline NiAl-based alloys are their room-temperature and high-temperature brittleness, which interferes with potential structural applications. This brittleness is generally attributed to the inability of dislocations to move in the highly ordered lattices. The introduction of small amount of boron can drastically increase the ductility by suppressing intergranular fracture.
Ni-based superalloys derive their strength from the formation of γ precipitates (NiAl) in the γ phase (Ni) which strengthen the alloys through precipitation hardening. In these alloys the volume fraction of the γ precipitates is as high as 80%. Because of this high volume fraction, the evolution of these γ precipitates during the alloys life cycles is important: a major concern is the coarsening of these γ precipitates at high temperature (800 to 1000 °C), which greatly reduces the alloys strength. This coarsening is due to the balance between interfacial and elastic energy in the γ + γ phase and is generally inevitable over long durations of time. This coarsening problem is addressed by introducing other elements such as Fe, Cr and Mo, which generate multiphase configurations that can significantly increase the creep resistance. This creep resistance is attributed to the formation of inhomogeneous precipitate CrMoNi, which pins dislocations and prevents further coarsening of the γ phase. The addition of Fe and Cr also drastically increases the weldability of the alloy. | 0 | Metallurgy |
Copper goes through a natural oxidation process that forms a unique protective patina on the metal. The surface of the metal undergoes a series of color changes: from iridescent/salmon pinks to oranges and reds interspersed with brassy yellows, blues, greens and purples. As the oxide thickens, these colors are replaced by russet and chocolate browns, dull slate grays or blacks, and finally to a light-green or blue-green.
Copper's patination process is complex. It starts immediately on exposure to the environment with the initial formation of copper oxide conversion films that are noticeable within six months. Weathering may be uneven at first but the film becomes even after about nine months. Within the first few years, cuprous and cupric sulfide conversion films darken the surface to browns and then dull slate gray or dull black. Continued weathering transforms the sulfide films to sulfates, which are the notable blue-green or gray-green patinas.
The rate of patination conversion is dependent upon copper's exposure to moisture, salt, and acidity from acid-forming pollutants. In marine climates, the entire patination process can take seven to nine years. In industrial environments, patina formation reaches its final stage in about fifteen to twenty-five years. In clean rural atmospheres with low concentrations of airborne sulfur dioxide, the final stage may take ten to thirty years to develop. In arid environments, a patina may not form at all if the moisture is insufficient. Where patination does take place in arid environments, it may mature to an ebony or nut brown. In all environments except the coastal areas, patination takes longer for vertical surfaces due to more rapid water runoff.
The copper patinas are very thin: just in thickness. Yet, they are highly adherent to the underlying copper metal. The initial and intermediate oxide and sulfide patina films are not particularly corrosion resistant. The final sulfate patina is a particularly durable layer that is highly resistant to all forms of atmospheric corrosion and protects the underlying metal against further weathering. As patination progresses and the durable sulfate layer forms, the rate of corrosion decreases, averaging between per year. For a sheet, this equates to less than 5% corrosion over a period of 100 years. Further information is available on copper patination. | 0 | Metallurgy |
Complex metallic alloys (CMAs) or complex intermetallics (CIMs) are intermetallic compounds characterized by the following structural features:
#large unit cells, comprising some tens up to thousands of atoms,
#the presence of well-defined atom clusters, frequently of icosahedral point group symmetry,
#the occurrence of inherent disorder in the ideal structure. | 0 | Metallurgy |
A well studied pioneer factor family is the Groucho-related (Gro/TLE/Grg) transcription factors that often have a negative effect on transcription. These chromatin binding domains can span up to 3-4 nucleosomes. These large domains are scaffolds for further protein interactions and also modify the chromatin for other pioneer factors such as FoxA1 which has been shown to bind to Grg3. Transcription factors with zinc finger DNA binding domains, such as the GATA family and glucocorticoid receptor. The zinc finger domains do not appear to bind nucleosomes well and can be displaced by FOX factors.
In the skin epidermis, SOX family transcription factor, SOX9, also behaves as a pioneer factor that governs hair follicle cell fate and can reprogram epidermal stem cells to a hair follicle fate. | 1 | Gene expression + Signal Transduction |
A15 phases are intermetallic alloys with an average coordination number (ACN) of 13.5 and eight AB stoichiometry atoms per unit cell where two B atoms are surrounded by CN12 polyhedral (icosahedra), and six A atoms are surrounded by CN14 polyhedral. NbGe is a superconductor with A15 structure. | 0 | Metallurgy |
The first event appears to be the accumulation of cell adhesion molecules such as NF186 or NrCAM. The intra-cellular regions of these cell-adhesion molecules interact with ankyrin G, which serves as an anchor for sodium channels. At the same time, the periaxonal extension of the glial cell wraps around the axon, giving rise to the paranodal regions. This movement along the axon contributes significantly to the overall formation of the nodes of Ranvier by permitting heminodes formed at the edges of neighboring glial cells to fuse into complete nodes.
Septate-like junctions form at the paranodes with the enrichment of NF155 in glial paranodal loops. Immediately following the early differentiation of the nodal and paranodal regions, potassium channels, Caspr2 and TAG1 accumulate in the juxta-paranodal regions. This accumulation coincides directly with the formation of compact myelin. In mature nodal regions, interactions with the intracellular proteins appear vital for the stability of all nodal regions. In the CNS, oligodendrocytes do not possess microvilli, but appear capable to initiate the clustering of some axonal proteins through secreted factors. The combined effects of such factors with the subsequent movements generated by the wrapping of oligodendrocyte periaxonal extension could account for the organization of CNS nodes of Ranvier. | 1 | Gene expression + Signal Transduction |
Inflammation is the bodys response to foreign objects, irritants, germs, and even pathogens. Although such a response is standard in some cases, if left untreated, chronic inflammation can lead to muscle degeneration, gastrointestinal disorders, and some types of cancers. While most treatments, such as anti-inflammatory drugs and steroid injections, can help relieve symptoms, they often fail to address the conditions underlying cause. Therefore, researchers have sought to explore new and innovative ways of inflammation treatment, such as chemotactic drug delivery.
One promising drug delivery system was based on engineered neutrophils that targeted inflammation sites through chemotaxis's unique properties. This approach took advantage of the concentration difference between iNOS and ROS for inflammatory disease sites and normal tissues. By doing so, this drug delivery system provides the possibility to target areas of inflammation, increase drug efficacy, and minimize damage to the surrounding tissue. Moreover, because this concentration gradient is ubiquitous in the microenvironment of inflammatory diseases, common drug-targeting limitations such as individual differences can be avoided. Another example of an innovative drug delivery system that uses the property of chemotaxis is leukocytes. Indeed, during inflammation, the molecules on a cell that allows for adhesion are overly produced. With this unique condition, researchers can modify leukocytes to quickly detect the cell, attach itself to the surface, and deliver a therapeutic payload. Overall, many promising therapies and drug delivery systems are being developed to target inflammation more effectively. Chemotactic drug delivery systems are just one of many promising avenues that seek to increase target sites specifically, decreasing the needed drug dosage, reducing toxicity, and increasing drug efficacy. | 1 | Gene expression + Signal Transduction |
Fixed aRME are established either by silencing of one allele that previously has been biallelically expressed, or by activation of a single allele from previously silent gene. Expression activation of the silent allele is coupled with a feedback mechanism that prevents expression of the second allele. Another scenario is also possible due to limited time-window of low-probability initiation, that could lead to high frequencies of cells with single-allele expression. It is estimated that 2-10% of all genes are fixed aRME. Studies
of fixed aRME require either expansion of monoclonal cultures or lineage-traced in vivo or in vitro cells that are mitotically.
Dynamic aRME occurs as a consequence of stochastic allelic expression. Transcription happens in bursts, which results in RNA molecules being synthesized from each allele separately. So over time, both alleles have a probability to initiate transcription. Transcriptional bursts are allelically stochastic, and lead to either maternal or paternal allele being accumulated in the cell. The gene transcription burst frequency and intensity combined with RNA-degradation rate form the shape of RNA distribution at the moment of observation and thus whether the gene is bi- or monoallelic. Studies that distinguish fixed and dynamic aRME require single-cell analyses of clonally related cells. | 1 | Gene expression + Signal Transduction |
Blast furnaces operate on the principle of chemical reduction whereby carbon monoxide converts iron oxides to elemental iron. Blast furnaces differ from bloomeries and reverberatory furnaces in that in a blast furnace, flue gas is in direct contact with the ore and iron, allowing carbon monoxide to diffuse into the ore and reduce the iron oxide. The blast furnace operates as a countercurrent exchange process whereas a bloomery does not. Another difference is that bloomeries operate as a batch process whereas blast furnaces operate continuously for long periods. Continuous operation is also preferred because blast furnaces are difficult to start and stop. Also, the carbon in pig iron lowers the melting point below that of steel or pure iron; in contrast, iron does not melt in a bloomery.
Silica has to be removed from the pig iron. It reacts with calcium oxide (burned limestone) and forms silicates, which float to the surface of the molten pig iron as slag. Historically, to prevent contamination from sulfur, the best quality iron was produced with charcoal.
The downward moving column of ore, flux, coke or charcoal and reaction products must be sufficiently porous for the flue gas to pass through. To ensure this permeability the particle size of the coke or charcoal is of great relevance. Therefore, the coke must be strong enough so it will not be crushed by the weight of the material above it. Besides the physical strength of its particles, the coke must also be low in sulfur, phosphorus, and ash.
The main chemical reaction producing the molten iron is:
:FeO + 3CO → 2Fe + 3CO
This reaction might be divided into multiple steps, with the first being that preheated air blown into the furnace reacts with the carbon in the form of coke to produce carbon monoxide and heat:
:2 C + O → 2 CO
The hot carbon monoxide is the reducing agent for the iron ore and reacts with the iron oxide to produce molten iron and carbon dioxide. Depending on the temperature in the different parts of the furnace (warmest at the bottom) the iron is reduced in several steps. At the top, where the temperature usually is in the range between 200 °C and 700 °C, the iron oxide is partially reduced to iron(II,III) oxide, FeO.
:3 FeO + CO → 2 FeO + CO
The temperatures 850 °C, further down in the furnace, the iron(II,III) is reduced further to iron(II) oxide:
:FeO + CO → 3 FeO + CO
Hot carbon dioxide, unreacted carbon monoxide, and nitrogen from the air pass up through the furnace as fresh feed material travels down into the reaction zone. As the material travels downward, the counter-current gases both preheat the feed charge and decompose the limestone to calcium oxide and carbon dioxide:
:CaCO → CaO + CO
The calcium oxide formed by decomposition reacts with various acidic impurities in the iron (notably silica), to form a fayalitic slag which is essentially calcium silicate, :
:SiO + CaO → CaSiO
As the iron(II) oxide moves down to the area with higher temperatures, ranging up to 1200 °C degrees, it is reduced further to iron metal:
:FeO + CO → Fe + CO
The carbon dioxide formed in this process is re-reduced to carbon monoxide by the coke:
:C + CO → 2 CO
The temperature-dependent equilibrium controlling the gas atmosphere in the furnace is called the Boudouard reaction:
::2CO CO + C
The pig iron produced by the blast furnace has a relatively high carbon content of around 4–5% and usually contains too much sulphur, making it very brittle, and of limited immediate commercial use. Some pig iron is used to make cast iron. The majority of pig iron produced by blast furnaces undergoes further processing to reduce the carbon and sulphur content and produce various grades of steel used for construction materials, automobiles, ships and machinery. Desulphurisation usually takes place during the transport of the liquid steel to the steelworks. This is done by adding calcium oxide, which reacts with the iron sulfide contained in the pig iron to form calcium sulfide (called lime desulfurization). In a further process step, the so-called basic oxygen steelmaking, the carbon is oxidized by blowing oxygen onto the liquid pig iron to form crude steel.
Although the efficiency of blast furnaces is constantly evolving, the chemical process inside the blast furnace remains the same. One of the biggest drawbacks of the blast furnaces is the inevitable carbon dioxide production as iron is reduced from iron oxides by carbon and as of 2016, there is no economical substitute – steelmaking is one of the largest industrial contributors of the CO emissions in the world (see greenhouse gases). Several alternatives are being investigated such as plastic waste, biomass or hydrogen as reducing agent, which can substantially reduce the carbon emissions. The injection of, for example, hydrogen into blast furnaces can reduce carbon emissions by 20 percent.
The challenge set by the greenhouse gas emissions of the blast furnace is being addressed in an ongoing European Program called ULCOS (Ultra Low CO Steelmaking). Several new process routes have been proposed and investigated in depth to cut specific emissions ( per ton of steel) by at least 50%. Some rely on the capture and further storage (CCS) of , while others choose decarbonizing iron and steel production, by turning to hydrogen, electricity and biomass. In the nearer term, a technology that incorporates CCS into the blast furnace process itself and is called the Top-Gas Recycling Blast Furnace is under development, with a scale-up to a commercial size blast furnace under way. | 0 | Metallurgy |
The Scenedesmus obliquus mitochondrial code (translation table 22) is a genetic code found in the mitochondria of Scenedesmus obliquus, a species of green algae. | 1 | Gene expression + Signal Transduction |
Sintering in practice is the control of both densification and grain growth. Densification is the act of reducing porosity in a sample, thereby making it denser. Grain growth is the process of grain boundary motion and Ostwald ripening to increase the average grain size. Many properties (mechanical strength, electrical breakdown strength, etc.) benefit from both a high relative density and a small grain size. Therefore, being able to control these properties during processing is of high technical importance. Since densification of powders requires high temperatures, grain growth naturally occurs during sintering. Reduction of this process is key for many engineering ceramics. Under certain conditions of chemistry and orientation, some grains may grow rapidly at the expense of their neighbours during sintering. This phenomenon, known as abnormal grain growth (AGG), results in a bimodal grain size distribution that has consequences for the mechanical, dielectric and thermal performance of the sintered material.
For densification to occur at a quick pace it is essential to have (1) an amount of liquid phase that is large in size, (2) a near complete solubility of the solid in the liquid, and (3) wetting of the solid by the liquid. The power behind the densification is derived from the capillary pressure of the liquid phase located between the fine solid particles. When the liquid phase wets the solid particles, each space between the particles becomes a capillary in which a substantial capillary pressure is developed. For submicrometre particle sizes, capillaries with diameters in the range of 0.1 to 1 micrometres develop pressures in the range of to for silicate liquids and in the range of to for a metal such as liquid cobalt.
Densification requires constant capillary pressure where just solution-precipitation material transfer would not produce densification. For further densification, additional particle movement while the particle undergoes grain-growth and grain-shape changes occurs. Shrinkage would result when the liquid slips between particles and increases pressure at points of contact causing the material to move away from the contact areas, forcing particle centers to draw near each other.
The sintering of liquid-phase materials involves a fine-grained solid phase to create the needed capillary pressures proportional to its diameter, and the liquid concentration must also create the required capillary pressure within range, else the process ceases. The vitrification rate is dependent upon the pore size, the viscosity and amount of liquid phase present leading to the viscosity of the overall composition, and the surface tension. Temperature dependence for densification controls the process because at higher temperatures viscosity decreases and increases liquid content. Therefore, when changes to the composition and processing are made, it will affect the vitrification process. | 0 | Metallurgy |
Survivin is shown to be clearly regulated by the cell cycle, as its expression is found to be dominant only in the G2/M phase. This regulation exists at the transcriptional level, as there is evidence of the presence of cell-cycle-dependent element/cell-cycle gene homology region (CDE/CHR)boxes located in the survivin promoter region. Further evidence to support this mechanism of regulation includes the evidence that surivin is poly-ubiquinated and degraded by proteasomes during interphase of the cell cycle. Moreover, survivin has been shown to localize to components of the mitotic spindle during metaphase and anaphase of mitosis. Physical association between polymerized tubulin and survivin have been shown in vitro as well. It is also shown that post-transcriptional modification of survivin involving the phosphorylation of Thr34 leads to increased protein stability in the G2/M phase of the cell cycle.
It is known from Mirza et al. that repression of survivin by p53 is not a result of any cell cycle progressive regulation. The same experiment by Mirza et al. with regard to determining p53 suppression of survivin at the transcriptional level was repeated, but this time for cells arrested in different stages of the cell cycle. It was shown that, although p53 arrests the numbers of cells to different extents in different phases, the measured level of survivin mRNA and protein levels were the same across all the samples transfected with the wild-type p53. This shows that p53 acts in a cell-cycle independent manner to inhibit survivin expression. | 1 | Gene expression + Signal Transduction |
RoXaN is capable of interacting with NSP3 in vivo and during rotavirus infection. Domains of interaction correspond to the dimerization domain of NSP3 (amino acids 163 to 237) and the LD domain of RoXaN (amino acids 244 to 341). The interaction between NSP3 and RoXaN does not impair the interaction between NSP3 and eIF4G I, and a ternary complex made of NSP3, RoXaN, and eIF4G I can be detected in rotavirus-infected cells, implicating RoXaN in translation regulation.
Expression of RoXaN was found to be correlated with a higher tumor grad in GIST (gastrointestinal stromal tumors). | 1 | Gene expression + Signal Transduction |
The thermal effective mass of electrons in a metal is the apparent mass due to interactions with the periodic potential of the crystal lattice, with phonons (e.g. phonon drag), and interaction with other electrons. The resulting effective mass of electrons contributes to the electronic heat capacity of the metal, leading to deviations from the heat capacity of a free electron gas. | 0 | Metallurgy |
In general, the most important requisite is to calibrate the incubation time of the assay both to the model cell and the ligand to be evaluated. Too short incubation time results in no cells in the sample, while too long time perturbs the concentration gradients and measures more chemokinetic than chemotactic responses.
The most commonly used techniques are grouped into two main groups: | 1 | Gene expression + Signal Transduction |
An action potential is a spike of both positive and negative ionic discharge that travels along the membrane of a cell. The creation and conduction of action potentials represents a fundamental means of communication in the nervous system. Action potentials represent rapid reversals in voltage across the plasma membrane of axons. These rapid reversals are mediated by voltage-gated ion channels found in the plasma membrane.
The action potential travels from one location in the cell to another, but ion flow across the membrane occurs only at the nodes of Ranvier. As a result, the action potential signal jumps along the axon, from node to node, rather than propagating smoothly, as they do in axons that lack a myelin sheath. The clustering of voltage-gated sodium and potassium ion channels at the nodes permits this behavior. | 1 | Gene expression + Signal Transduction |
Both sexual and asexual reproductions are implemented. Asexual reproduction is implemented as producing the offsprings genome (the gene network) by directly copying the parents genome. Sexual reproduction is implemented as the recombination of the two parents' genomes. | 1 | Gene expression + Signal Transduction |
*Agricola, Georgius, 1556, Translation Hoover, Herbert, 1912, De re metallica, [http://farlang.com/books/agricola-hoover-de-re-metallica Farlang, full streaming version + scientific introduction]
*Craddock, P. T., 1989. Metalworking Techniques. In: Youngs, S. (ed), Work of Angels: Masterpieces of Celtic Metalwork, 6th-9th centuries AD, 170–213.
*Forbes, R. J., 1957. Metallurgy. In: Singer, C., Holmyard, E. J., Hall, A. R. & Williams, T. I. (eds), A History of Technology, vol. 2: The Mediterranean Civilizations and the Middle Ages c. 700 BC to AD 1500. Oxford: Clarendon Press, 41–80.
*Martinon-Torres, M. & Rehren, Th., in press (a). Metallurgy, Europe. In: Encyclopedia of Society and Culture in the Medieval World. Dallas: Schlager.
*Martinon-Torres, M. & Rehren, Th., in press (b). Mining, Europe. In: Encyclopedia of Society and Culture in the Medieval World. Dallas: Schlager.
*Smith, C.S. & Hawthorne, J.H., 1974. Mappae Clavicula, A little key to the world of medieval techniques. Transactions of American Philosophical Society 64 (4), 1–128.
*Theophilus, On Divers Arts: The foremost medieval treatise on Painting, Glassmaking and Metalwork. Hawthorne, J.G. & Smith, C.S. (trans), 1979. New York: Dover Publications. | 0 | Metallurgy |
In order for paracrine factors to successfully induce a response in the receiving cell, that cell must have the appropriate receptors available on the cell membrane to receive the signals, also known as being competent. Additionally, the responding cell must also have the ability to be mechanistically induced. | 1 | Gene expression + Signal Transduction |
Two classes of transcription terminators, Rho-dependent and Rho-independent, have been identified throughout prokaryotic genomes. These widely distributed sequences are responsible for triggering the end of transcription upon normal completion of gene or operon transcription, mediating early termination of transcripts as a means of regulation such as that observed in transcriptional attenuation, and to ensure the termination of runaway transcriptional complexes that manage to escape earlier terminators by chance, which prevents unnecessary energy expenditure for the cell. | 1 | Gene expression + Signal Transduction |
Genome-wide association studies (GWAS) identify linkages between alleles and observable traits such as phenotypes and diseases. Most of the associations are between single-nucleotide polymorphisms (SNPs) and the trait being examined and most of these SNPs are located in non-functional DNA. The association establishes a linkage that helps map the DNA region responsible for the trait but it does not necessarily identify the mutations causing the disease or phenotypic difference.
SNPs that are tightly linked to traits are the ones most likely to identify a causal mutation. (The association is referred to as tight linkage disequilibrium.) About 12% of these polymorphisms are found in coding regions; about 40% are located in introns; and most of the rest are found in intergenic regions, including regulatory sequences. | 1 | Gene expression + Signal Transduction |
The probe to be detected is labeled with some biotin-molecules. After incubation with a gold-coupled anti-biotin conjugate, silver nitrate and a reducing agent are added. The reaction starts whereas the gold particle serves as a starting point for the silver precipitation.
The reaction needs to be stopped after a specific time. The constant reaction time is essential to obtain comparable results. | 1 | Gene expression + Signal Transduction |
In a multiple-hearth roaster, the concentrate drops through a series of 9 or more hearths stacked inside a brick-lined cylindrical column. As the feed concentrate drops through the furnace, it is first dried by the hot gases passing through the hearths and then oxidized to produce calcine. The reactions are slow and can be sustained only by the addition of fuel. Multiple hearth roasters are unpressurized and operate at about . Operating time depends upon the composition of concentrate and the amount of the sulfur removal required. Multiple hearth roasters have the capability of producing a high-purity calcine. | 0 | Metallurgy |
Highly repetitive DNA consists of short stretches of DNA that are repeated many times in tandem (one after the other). The repeat segments are usually between 2 bp and 10 bp but longer ones are known. Highly repetitive DNA is rare in prokaryotes but common in eukaryotes, especially those with large genomes. It is sometimes called satellite DNA.
Most of the highly repetitive DNA is found in centromeres and telomeres (see above) and most of it is functional although some might be redundant. The other significant fraction resides in short tandem repeats (STRs; also called microsatellites) consisting of short stretches of a simple repeat such as ATC. There are about 350,000 STRs in the human genome and they are scattered throughout the genome with an average length of about 25 repeats.
Variations in the number of STR repeats can cause genetic diseases when they lie within a gene but most of these regions appear to be non-functional junk DNA where the number of repeats can vary considerably from individual to individual. This is why these length differences are used extensively in DNA fingerprinting. | 1 | Gene expression + Signal Transduction |
Mono(ADP-ribosyl)transferases commonly catalyze the addition of ADP-ribose to arginine side chains using a highly conserved R-S-EXE motif of the enzyme. The reaction proceeds by breaking the bond between nicotinamide and ribose to form an oxonium ion. Next, the arginine side chain of the target protein then acts a nucleophile, attacking the electrophilic carbon adjacent to the oxonium ion. In order for this step to occur, the arginine nucleophile is deprotonated by a glutamate residue on the catalyzing enzyme. Another conserved glutamate residue forms a hydrogen bond with one of the hydroxyl groups on the ribose chain to further facilitate this nucleophilic attack. As a result of the cleavage reaction, nicotinamide is released. The modification can be reversed by (ADP-ribosyl)hydrolases, which cleave the N-glycosidic bond between arginine and ribose to release ADP-ribose and unmodified protein; NAD is not restored by the reverse reaction. | 1 | Gene expression + Signal Transduction |
Most ceramics are extremely hard and must be wet-sawed with a circular blade embedded with diamond particles. A metallography or lapidary saw equipped with a low-density diamond blade is usually suitable. The blade must be cooled by a continuous liquid spray. | 0 | Metallurgy |
Spt-Ada-Gcn5 acetyltransferase (SAGA) is a histone modifying transcriptional co-activator that is composed of 21 proteins and exhibits histone acetyltransferase (HAT) and deubiquitinating (DUB) activity. In yeast the SAGA complex serves to activate the transcription of approximately 10% of the genome, and this active gene/SAGA complex is then able to interact with the TREX-2 complex, a NPC-associated mRNA export complex. Numerous proteins involved in the formation of mRNA interact with the NPC, with the majority of these protein-protein interactions occurring between the SAGA complex and the TREX-2 complex at the NPC. Correct transcription and subsequent export of mRNA is largely dependent on this interaction. A common protein subunit of both the SAGA and TREX-2 complexes, Sus1, binds to the upstream activating sequence via SAGA, which then serves as the attachment point to the TREX-2 complex. The interacting surfaces between Sus1 and the TREX-2 complex are facilitated by the protein subunits Mex67 and Yra1 of the TREX-2 complex, as evidenced by co-immunoprecipitation experiments. The TREX-2 complex is bound to the NPC complex by the nucleoporin Nup1. All TREX-2 subunits are necessary for the successful formation and export of an mRNA transcript at the nuclear membrane for genes activated by the SAGA complex, and data suggest that SAGA and TREX-2 act in concert to recruit Sus1 to genes to be transcribed. Other investigations have shown that several SAGA subunits interact with the NPC protein Mlp1, providing another link between the NPC and the SAGA/active gene complex. | 1 | Gene expression + Signal Transduction |
In order for proper gene expression to occur, transcription must stop at specific sites. Two termination mechanisms are well known:
*Intrinsic termination (also called Rho-independent termination): Specific DNA nucleotide sequences signal the RNA polymerase to stop. The sequence is commonly a palindromic sequence that causes the strand to loop which stalls the RNA polymerase. Generally, this type of termination follows the same standard procedure. A pause will occur due to a polyuridine sequence that allows the formation of a hairpin loop. This hairpin loop will aid in forming a trapped complex, which will ultimately cause the dissociation of RNA polymerase from the template DNA strand and halt transcription.
*Rho-dependent termination: ρ factor (rho factor) is a terminator protein that attaches to the RNA strand and follows behind the polymerase during elongation. Once the polymerase nears the end of the gene it is transcribing, it encounters a series of G nucleotides which causes it to stall. This stalling allows the rho factor to catch up to the RNA polymerase. The rho protein then pulls the RNA transcript from the DNA template and the newly synthesized mRNA is released, ending transcription. Rho factor is a protein complex that also displays helicase activities (is able to unwind the nucleic acid strands). It will bind to the DNA in cytosine rich regions and when RNA polymerase encounters it, a trapped complex will form causing the dissociation of all molecules involved and end transcription.
The termination of DNA transcription in bacteria may be stopped by certain mechanisms wherein the RNA polymerase will ignore the terminator sequence until the next one is reached. This phenomenon is known as antitermination and is utilized by certain bacteriophages. | 1 | Gene expression + Signal Transduction |
Many countries, including India, France and Germany, have underground deposits of iron ore in dust form (blue dust). Such iron ore cannot be directly charged in a blast furnace. In the early 20th century, sinter technology was developed for converting ore fines into lumpy material chargeable in blast furnaces. Sinter technology took 30 years to gain acceptance in the iron-making domain, but now plays an important role. Initially developed to generate steel, it is now a means of using metallurgical waste generated in steel plants to enhance blast furnace operation and reducing waste. The largest sinter plant is located in Chennai, India, and employs 10,000 people. | 0 | Metallurgy |
Until the early 19th century, the usual method of producing wrought iron involved a charcoal-fired finery in a finery forge. In the beginning of the 19th century this became an obsolete process and was slowly replaced by the coal-fueled puddling process. However, charcoal continued to be used in some forges after most of the iron industry had abandoned it for coke.
In 1813 when John Bradley & Co. (whose leading partner was James Foster) took over forges at Eardington in Shropshire, a potting and stamping forge, they reverted to using charcoal. In 1820, he bought Hampton Loade Forge, which then became a tinplate works and in 1826 another charcoal forge. This was followed by other charcoal forges at Horsehay in 1832 and at the Old Park ironworks of the Botfield family about 1826. Cookley Forge in the Stour valley also reverted to charcoal working in 1814, supplying wire and tinplate mills.
By the 1830s, these forges were sometimes producing over 2000 tons of iron per year, compared with a few hundred from earlier finery forges. It is likely that these forges were using a more efficient variety of hearth, which from Swedish usage has come to be known as a Lancashire hearth. | 0 | Metallurgy |
This form of corrosion occurs principally in metal alloys. The less noble metal of the alloy, is selectively leached from the alloy. Removal of zinc from brass is a more common example. | 0 | Metallurgy |
PHLPP is a member of the PPM family of phosphatases, which requires magnesium or manganese for their activity and are insensitive to most common phosphatase inhibitors, including [okadaic acid]. PHLPP1 and PHLPP2 have a similar domain structure, which includes a putative Ras association domain, a pleckstrin homology domain, a series of leucine-rich repeats, a PP2C phosphatase domain, and a C-terminal PDZ ligand. PHLPP1 has two splice variants, PHLPP1α and PHLPP1β, of which PHLPP1β is larger by approximately 1.5 kilobase pairs. PHLPP1α, which was the first PHLPP isoform to be characterized, lacks the N-terminal portion of the protein, including the Ras association domain. PHLPP's domain structure influences its ability to dephosphorylate its substrates. A PHLPP construct lacking the PH domain is unable to decrease PKC phosphorylation, while PHLPP lacking the PDZ ligand is unable to decrease Akt phosphorylation. | 1 | Gene expression + Signal Transduction |
Capping is a three-step process that utilizes the enzymes RNA triphosphatase, guanylyltransferase, and methyltransferase. Through a series of three steps, the cap is added to the first nucleotides 5 hydroxyl group of the growing mRNA strand while transcription is still occurring. First, RNA 5 triphosphatase hydrolyzes the 5 triphosphate group to make diphosphate-RNA. Then, the addition of GMP by guanylyltransferase produces the guanosine cap. Last, RNA methyltransferase transfers a methyl group to the guanosine cap to yield 7-methylguanosine cap that is attached to the 5' end of the transcript. These three enzymes, collectively called the capping enzymes, are only able to catalyze their respective reactions when attached to RNA polymerase II, an enzyme necessary for the transcription of DNA into pre-mRNA. When this complex of RNA polymerase II and the capping enzymes is achieved, the capping enzymes are able to add the cap to the mRNA while it is produced by RNA polymerase II. | 1 | Gene expression + Signal Transduction |
Reciprocal silencing on the tissue level refers to the same pattern of silencing and expression of homeologous loci. However, in this case, the differences in silencing and expression occur between two types of tissue within the same individual, rather than in individuals of different populations. This is an example of neofunctionalization, a process where duplicated genes that were once at equivalent loci evolve to carry out two separate functions. Since different tissues require different genes to be expressed, reciprocal silencing can occur between tissues. Importantly, while the pattern of gene expression is the same as in the population case, the genetic means by which this pattern is achieved are very different. While silencing mutations are thought to be the main source of reciprocal silencing
at the population level, at the tissue level only epigenetic factors are in play, since expressible copies of both homeologous loci must exist in all cells in an individual if different tissues express different homeologs. | 1 | Gene expression + Signal Transduction |
Interferome offers many ways of searching and retrieving data from the database:
*Identify interferon regulated gene signatures in microarray data;
*Gene Ontology analysis and annotation;
*Normal tissue expression of interferon regulated genes;
*Regulatory analysis of interferon regulated genes;
*BLAST (Basic Local Alignment Search Tool) analysis and orthologue sequence download; | 1 | Gene expression + Signal Transduction |
Subsets and Splits