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An example of desirable work hardening is that which occurs in metalworking processes that intentionally induce plastic deformation to exact a shape change. These processes are known as cold working or cold forming processes. They are characterized by shaping the workpiece at a temperature below its recrystallization temperature, usually at ambient temperature. Cold forming techniques are usually classified into four major groups: squeezing, bending, drawing, and shearing. Applications include the heading of bolts and cap screws and the finishing of cold rolled steel. In cold forming, metal is formed at high speed and high pressure using tool steel or carbide dies. The cold working of the metal increases the hardness, yield strength, and tensile strength. | 0 | Metallurgy |
Cathodic protection is a technique used to inhibit corrosion on buried or immersed structures by supplying an electrical charge that suppresses the electrochemical reaction. If correctly applied, corrosion can be stopped completely. In its simplest form, it is achieved by attaching a sacrificial anode, thereby making the iron or steel the cathode in the cell formed. The sacrificial anode must be made from something with a more negative electrode potential than the iron or steel, commonly zinc, aluminium, or magnesium. The sacrificial anode will eventually corrode away, ceasing its protective action unless it is replaced in a timely manner.
Cathodic protection can also be provided by using an applied electrical current. This would then be known as ICCP Impressed Current Cathodic Protection. | 0 | Metallurgy |
Detonation spraying produces coatings of very high chemical bond strength and hardness. Coatings are of low porosity, oxygen content and have a low to medium surface roughness. This is achieved due to the extremely high temperatures and velocities produced by the detonation gun during surface coating application. These properties make detonation spraying the standard of comparison for all other thermal spray coatings (wire arc, plasma, flame, HVAF, HVOF, Warm, Cold).
There are many factors that determine the final detonation gun coating properties. Primarily, surface properties are determined by the type and properties of the powdered feedstock used (composition and particle size) but they are also affected by the settings used on the D-gun. These are powder flow rate, firing rate, distance from gun to target, how the D-gun is moved around to apply the coating, size of barrel, amount and composition of fuel and oxygen mixture.
Detonation spraying is able to apply protective coatings to relatively sensitive and delicate materials. This is due to the nature of the application of detonation gun coatings, being very quick and having the heat source removed from the target material. This allows for a large range of suitable applications for detonation spraying. | 0 | Metallurgy |
; General
* Aitchison, Leslie. 1960. A History of Metals. London: Macdonald & Evans Ltd.
* Bayley, Justine; Butcher, Sarnia. 2004. Roman Brooches in Britain: A Technological and Typological Study based on the Richborough Collection. London: The Society of Antiquaries of London.
* Craddock, Paul T. 1995. Early Metal Mining and Production. Edinburgh: Edinburgh University Press.
* Craddock, Paul T. 1999. Paradigms of Metallurgical Innovation in Prehistoric Europe in Hauptmann, A., Ernst, P., Rehren, T., Yalcin, U. (eds). The Beginnings of Metallurgy: Proceedings of the International Conference “The Beginnings of Metallurgy”, Bochum 1995. Hamburg
* Davies, O. Roman Mines in Europe 1935., Oxford University Press
* Hughes, M. J. 1980 The Analysis of Roman Tin and Pewter Ingots in Ody, W. A. (ed) Aspects of Early Metallurgy. Occasional Paper No 17. British Museum Occasional Papers.
* Shepard, Robert. 1993. Ancient Mining. London: Elsevier Applied Science.
* Sim, David. 1998. Beyond the Bloom: Bloom Refining and Iron Artifact Production in the Roman World. Ridge, Isabel (ed). BAR International Series 725. Oxford: Archaeopress.
* Tylecote, R.F. 1962. Metallurgy in Archaeology: A Prehistory of Metallurgy in the British Isles. London: Edward Arnold (Publishers) Ltd.
* Zwicker, U., Greiner, H., Hofmann, K-H., Reithinger, M. 1985. Smelting, Refining and Alloying of Copper and Copper Alloys in Crucible Furnaces During Prehistoric up to Roman Times in Craddock, P.T., Hughes, M.J. (eds) Furnaces and Smelting Technology in Antiquity. Occasional Paper No 48. London: British Museum Occasional Papers.
* J. S., Hodgkinson. 2008. "The Wealden Iron Industry." (The History Press, Stroud).
* Cleere, Henry. 1981. The Iron Industry of Roman Britain. Wealden Iron Research Group.
; Output
* Callataÿ, François de (2005): "The Graeco-Roman Economy in the Super Long-Run: Lead, Copper, and Shipwrecks", Journal of Roman Archaeology, Vol. 18, pp. 361–372
* Cech, Brigitte (2010): Technik in der Antike, Wissenschaftliche Buchgesellschaft, Darmstadt,
* Cleere, H. & Crossley, D. (1995): The Iron industry of the Weald. 2nd edition, Merton Priory Press, Cardiff, : republishing the 1st edition (Leicester University Press 1985) with a supplement.
* Cleere, Henry. 1981. The Iron Industry of Roman Britain. Wealden Iron Research Group. p. 74-75
* Craddock, Paul T. (2008): "Mining and Metallurgy", in: Oleson, John Peter (ed.): The Oxford Handbook of Engineering and Technology in the Classical World, Oxford University Press, , pp. 93–120
* Healy, John F. (1978): Mining and Metallurgy in the Greek and Roman World, Thames and Hudson, London,
* Hong, Sungmin; Candelone, Jean-Pierre; Patterson, Clair C.; Boutron, Claude F. (1994): "Greenland Ice Evidence of Hemispheric Lead Pollution Two Millennia Ago by Greek and Roman Civilizations", Science, Vol. 265, No. 5180, pp. 1841–1843
* Hong, Sungmin; Candelone, Jean-Pierre; Patterson, Clair C.; Boutron, Claude F. (1996): "History of Ancient Copper Smelting Pollution During Roman and Medieval Times Recorded in Greenland Ice", Science, Vol. 272, No. 5259, pp. 246–249
* Patterson, Clair C. (1972): "Silver Stocks and Losses in Ancient and Medieval Times", The Economic History Review, Vol. 25, No. 2, pp. 205–235
* Lewis, P. R. and G. D. B. Jones, The Dolaucothi gold mines, I: the surface evidence, The Antiquaries Journal, 49, no. 2 (1969): 244-72.
* Lewis, P. R. and G. D. B. Jones, Roman gold-mining in north-west Spain, Journal of Roman Studies 60 (1970): 169-85.
* Lewis, P. R., The Ogofau Roman gold mines at Dolaucothi, The National Trust Year Book 1976-77 (1977).
* Settle, Dorothy M.; Patterson, Clair C. (1980): "Lead in Albacore: Guide to Lead Pollution in Americans", Science, Vol. 207, No. 4436, pp. 1167–1176
* Sim, David; Ridge, Isabel (2002): Iron for the Eagles. The Iron Industry of Roman Britain, Tempus, Stroud, Gloucestershire,
* Smith, A. H. V. (1997): "Provenance of Coals from Roman Sites in England and Wales", Britannia, Vol. 28, pp. 297–324
* Wilson, Andrew (2002): "Machines, Power and the Ancient Economy", The Journal of Roman Studies, Vol. 92, pp. 1–32 | 0 | Metallurgy |
The IscR stability element is a conserved secondary structure found in the intergenic regions of iscRSUA polycistronic mRNA. This secondary structure prevents the degradation of the iscR mRNA.
The iscRSUA operon encodes for the proteins required in iron–sulfur cluster biosynthesis where the expression of this operon is regulated by RyhB and iscR, a transcription repressor. Under sufficient iron conditions RyhB binds to iscRSUA mRNA and promotes the degradation of the mRNA located downstream of iscR. Scanning the intergenic regions of this polycistronic mRNA and using Mfold software a secondary structure was predicted within the intergenic region between iscR and iscS and later confirmed by lead acetate probing. Mutations that disrupt this secondary structure resulted in the degradation of iscR mRNA after RyhB binding. 3′ RACE analysis of the iscR mRNA fragment identified the intergenic RNA at the 3′ end. These results suggest that this intergenic RNA element acts as an iscR mRNA stability element by protecting iscR from exonuclease degradation. | 1 | Gene expression + Signal Transduction |
A co-receptor is a cell surface receptor that binds a signalling molecule in addition to a primary receptor in order to facilitate ligand recognition and initiate biological processes, such as entry of a pathogen into a host cell. | 1 | Gene expression + Signal Transduction |
Sulfide stress cracking (SSC) is a form of hydrogen embrittlement which is a cathodic cracking mechanism. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Susceptible alloys, especially steels, react with hydrogen sulfide (), forming metal sulfides (MeS) and atomic hydrogen (H) as corrosion byproducts. Atomic hydrogen either combines to form H at the metal surface or diffuses into the metal matrix. Since sulfur is a hydrogen recombination poison, the amount of atomic hydrogen which recombines to form H on the surface is greatly reduced, thereby increasing the amount of diffusion of atomic hydrogen into the metal matrix. This aspect is what makes wet HS environments so severe.
Since SSC is a form of hydrogen embrittlement, it is most susceptibile to cracking at or slightly below ambient temperature.
Sulfide stress cracking has special importance in the gas and oil industry, as the materials being processed there (natural gas and crude oil) often contain considerable amounts of hydrogen sulfide. Equipment that comes in contact with HS environments can be rated for sour service with adherence to NACE MR0175/ISO 15156 for oil and gas production environments or NACE MR0103/ISO17945 for oil and gas refining environments.
"High Temperature Hydrogen Attack" (HTHA) does not rely on atomic hydrogen. At high temperature and high hydrogen partial pressure, hydrogen can diffuse into carbon steel alloys. In susceptible alloys, hydrogen combines with carbon within the alloy and forms methane. The methane molecules create a pressure buildup in the metal lattice voids, which leads to embrittlement and even cracking of the metal. | 0 | Metallurgy |
All ETS (Erythroblast Transformation Specific) family members are identified through a highly conserved DNA binding domain, the ETS domain, which is a winged helix-turn-helix structure that binds to DNA sites with a central GGA(A/T) DNA sequence. As well as DNA-binding functions, evidence suggests that the ETS domain is also involved in protein-protein interactions.
There is limited similarity outside the ETS DNA binding domain.
Other domains are also present and vary from ETS member to ETS member, including the Pointed domain, a subclass of the SAM domain family. | 1 | Gene expression + Signal Transduction |
β-Catenin was initially discovered in the early 1990s as a component of a mammalian cell adhesion complex: a protein responsible for cytoplasmatic anchoring of cadherins. But very soon, it was realized that the Drosophila protein armadillo – implicated in mediating the morphogenic effects of Wingless/Wnt – is homologous to the mammalian β-catenin, not just in structure but also in function. Thus, β-catenin became one of the first examples of moonlighting: a protein performing more than one radically different cellular function. | 1 | Gene expression + Signal Transduction |
Of the seven metals known in antiquity, only gold regularly occurs in nature as a native metal. The others – copper, lead, silver, tin, iron, and mercury – occur primarily as minerals, although native copper is occasionally found in commercially significant quantities. These minerals are primarily carbonates, sulfides, or oxides of the metal, mixed with other components such as silica and alumina. Roasting the carbonate and sulfide minerals in the air converts them to oxides. The oxides, in turn, are smelted into the metal. Carbon monoxide was (and is) the reducing agent of choice for smelting. It is easily produced during the heating process, and as a gas comes into intimate contact with the ore.
In the Old World, humans learned to smelt metals in prehistoric times, more than 8000 years ago. The discovery and use of the "useful" metals – copper and bronze at first, then iron a few millennia later – had an enormous impact on human society. The impact was so pervasive that scholars traditionally divide ancient history into Stone Age, Bronze Age, and Iron Age.
In the Americas, pre-Inca civilizations of the central Andes in Peru had mastered the smelting of copper and silver at least six centuries before the first Europeans arrived in the 16th century, while never mastering the smelting of metals such as iron for use with weapon craft. | 0 | Metallurgy |
As mining techniques and the price of minerals improve, it is not unusual for tailings to be reprocessed using new methods, or more thoroughly with old methods, to recover additional minerals. Extensive tailings dumps of Kalgoorlie / Boulder in Western Australia were re-processed profitably in the 1990s by KalTails Mining.
A machine called the PET4K Processing Plant has been used in a variety of countries for the past 20 years to remediate contaminated tailings. | 0 | Metallurgy |
Sintering occurs by diffusion of atoms through the microstructure. This diffusion is caused by a gradient of chemical potential – atoms move from an area of higher chemical potential to an area of lower chemical potential. The different paths the atoms take to get from one spot to another are the "sintering mechanisms" or "matter transport mechanisms".
In solid state sintering, the six common mechanisms are:
# surface diffusion – diffusion of atoms along the surface of a particle
# vapor transport – evaporation of atoms which condense on a different surface
# lattice diffusion from surface – atoms from surface diffuse through lattice
# lattice diffusion from grain boundary – atom from grain boundary diffuses through lattice
# grain boundary diffusion – atoms diffuse along grain boundary
# plastic deformation – dislocation motion causes flow of matter.
Mechanisms 1–3 above are non-densifying (i.e. do not cause the pores and the overall ceramic body to shrink) but can still increase the area of the bond or "neck" between grains; they take atoms from the surface and rearrange them onto another surface or part of the same surface. Mechanisms 4–6 are densifying – atoms are moved from the bulk material or the grain boundaries to the surface of pores, thereby eliminating porosity and increasing the density of the sample. | 0 | Metallurgy |
The basic leaching chemical formula that drives this process is:
This is achieved in practice through a process called double leaching. The calcine is first leached in a neutral or slightly acidic solution (of sulfuric acid) in order to leach the zinc out of the zinc oxide. The remaining calcine is then leached in strong sulfuric acid to leach the rest of the zinc out of the zinc oxide and zinc ferrite. The result of this process is a solid and a liquid; the liquid contains the zinc and is often called leach product; the solid is called leach residue and contains precious metals (usually lead and silver) which are sold as a by-product. There is also iron in the leach product from the strong acid leach, which is removed in an intermediate step, in the form of goethite, jarosite, and haematite. There is still cadmium, copper, arsenic, antimony, cobalt, germanium, nickel, and thallium in the leach product. Therefore, it needs to be purified. | 0 | Metallurgy |
Eukaryotic genes contain an upstream promoter and a core promoter also referred to as a basal promoter. A common basal promoter is the TATAAAAAA sequence known as the TATA box. The TATA box is a complex with several different proteins including transcription factor II D (TFIID) which includes the TATA-binding protein (TBP) that binds to the TATA box along with 13 other proteins that bind to TBP. The TATA box binding proteins also include the transcription factor II B (TFIIB) which binds to both DNA and RNA polymerases.
Silencers in eukaryotes control gene expression on a transcriptional level in which the mRNA is not transcribed. These DNA sequences may act as either silencers or enhancers based on the transcription factor that binds to the sequence and binding of this sequence will prevent promoters such as the TATA box from binding to RNA polymerase. A repressor protein may have regions that bind to the DNA sequence as well as regions that bind to the transcription factors assembled at the promoter of the gene which would create a chromosome looping mechanism. Looping brings silencers in close proximity to the promoters to ensure that groups of proteins needed for optimal gene expression will work together. | 1 | Gene expression + Signal Transduction |
Mediator is a multiprotein complex that functions as a transcriptional coactivator. The Mediator complex is required for the successful transcription of nearly all class II gene promoters in yeast. It works in the same manner in mammals.
The mediator functions as a coactivator and binds to the C-terminal domain (CTD) of RNA polymerase II holoenzyme, acting as a bridge between this enzyme and transcription factors. | 1 | Gene expression + Signal Transduction |
Waxes prepared with BTA are available commercially, the idea being that the BTA will prevent any reaction by chelating the surface copper and the wax acting as a physical barrier reducing exposure to water, oxygen, and chlorides; but coating an infected object with wax will not stop the problem. Storing the object in a completely dry or oxygen free environment will also prevent bronze disease as will isolation from contact with chlorides. | 0 | Metallurgy |
TGFβ signaling at the cell membrane results in 2 different intracellular pathways. One of them depends on MED15, while the other is independent of MED15. In both human cells and Caenorhabditis elegans MED15 is involved in lipid homeostasis through the pathway involving SREBPs In the model plant Arabidopsis thaliana the ortholog of MED15 is required for signaling by the plant hormone Salicylic acid, while MED25 is required for the transcriptional activation of jasmonate and shade signalling responses. Two components of the CDK module (MED12 and MED13) are involved in the Wnt signaling pathway MED23 is involved in RAS/MAPK/ERK pathway This abbreviated review shows the versatility of individual mediator subunits, and leads to the idea that mediator is an end-point of signaling pathways. | 1 | Gene expression + Signal Transduction |
The Long Harbour Nickel Processing Plant is a Canadian nickel concentrate processing facility located in Long Harbour, Newfoundland and Labrador.
Operated by Vale Limited, construction on the plant started in April 2009 and operations began in 2014. Construction costs were in excess of CAD $4.25 billion. Construction involved over 3,200 workers generating approximately 3,000 person-years of employment. Operation of the plant will require approximately 475 workers.
Production began in July 2014, reported in November 2014. Vales nickel processing plant in Long Harbour received its first major shipment from its Labrador mine in Voiseys Bay in May 2015. As of that date, a small proportion of the plants raw materials came from Voiseys Bay but the majority were imported from Indonesia. A spokesman for Vale said 100 per cent of the Long Harbour facilitys production materials will come from Voiseys Bay by early 2016.
Using the metal processing technology of hydrometallurgy, the plant is designed to produce per year of finished nickel product, together with associated cobalt and copper products. The hydrometallurgy technology was piloted at a demonstration plant that opened in Argentia, Newfoundland and Labrador in 2004. This demonstration plant operated until 2008 and was instrumental in helping Vale decide to use the hydrometallurgy process for the Long Harbour processing plant.
A processing plant on Newfoundland was one of the requirements established by the Government of Newfoundland and Labrador in order to exploit the nickel deposit at the Voiseys Bay Mine in Labrador. The bulk carrier MV Umiak I was one of several ice-strengthened bulk carriers built to transport nickel concentrate from Voiseys Bay to the Long Harbour Nickel Processing Plant.
The Long Harbour Nickel Processing Plant was built on a partially brownfield site near the port of Long Harbour. The facility consists of a wharf for offloading nickel ore concentrate from bulk carriers, crushing and grinding facilities, a main processing plant approximately south of the port, a pipeline to supply process water, an effluent discharge pipe and diffuser, and a residue pipeline to a nearby disposal area. The hydrometallurgical process in the plant will pressure-leach the nickel ore concentrate in acidic solutions to separate iron, sulfur and other impurities from nickel, copper and cobalt.
On June 11, 2018, Premier Dwight Ball announced Vale is moving forward with its underground mine at Voiseys Bay. Ball stated that the move will extend the mines operating life by at least 15 years. First ore is expected by April 2021 with processing to take place in Long Harbour. | 0 | Metallurgy |
The following individuals have held the position of President of this organization.
* 1871: David Thomas
* 1872–1874: Rossiter Worthington Raymond
* 1875: Alexander Lyman Holley
* 1876: Abram Stevens Hewitt
* 1877: Thomas Sterry Hunt
* 1878–1879: Eckley Brinton Coxe
* 1880: William Powell Shinn
* 1881: William Metcalf
* 1882: Richard Pennefather Rothwell
* 1883: Robert Woolston Hunt
* 1884–1885: James Cooper Bayles
* 1886: Robert Hallowell Richards
* 1887: Thomas Egleston
* 1888: William Bleeker Potter
* 1889: Richard Pearce
* 1890: Abram Stevens Hewitt
* 1891–1892: John Birkinbine
* 1893: Henry Marion Howe
* 1894: John Fritz
* 1895: Joseph D. Weeks
* 1896: Edmund Gybbon Spilsbury
* 1897: Thomas Messinger Drown
* 1898: Charles Kirchhoff
* 1899–1900: James Douglas
* 1901–1902: Eben Erskine Olcott
* 1903: Albert Reid Ledoux
* 1904–1905: James Gayley
* 1906: Robert Woolston Hunt
* 1907–1908: John Hays Hammond
* 1909–1910: David William Brunton
* 1911: Charles Kirchhoff
* 1912: James Furman Kemp
* 1913: Charles Frederic Rand
* 1914: Benjamin Bowditch Thayer
* 1915: William Lawrence Saunders
* 1916: Louis Davidson Ricketts
* 1917: Philip North Moore
* 1918: Sidney Johnston Jennings
* 1919: Horace Vaughn Winchell
* 1920: Herbert Hoover
* 1921: Edwin Ludlow
* 1922: Arthur Smith Dwight
* 1923: Edward Payson Mathewson
* 1924: William Kelly
* 1925: John van Wicheren Reynders
* 1926: Samuel A. Taylor
* 1927: Everette Lee DeGolyer
* 1928: George Otis Smith
* 1929: Frederick Worthen Bradley
* 1930: William Hastings Bassett
* 1931: Robert Emmet Tally
* 1932: Scott Turner
* 1933: Frederick Mark Becket
* 1934: Howard Nicholas Eavenson
* 1935: Henry Andrew Buehler
* 1936: John Meston Lovejoy
* 1937: Rolland Craten Allen
* 1938: Daniel Cowan Jackling
* 1939: Donald Burton Gillies
* 1940: Herbert George Moulton
* 1941: John Robert Suman
* 1942: Eugene McAuliffe
* 1943: Champion Herbert Mathewson
* 1944: Chester Alan Fulton
* 1945: Harvey Seeley Mudd
* 1946: Louis S. Cates
* 1947: Clyde Williams
* 1948: William Embry Wrather
* 1949: Lewis Emanuel Young
* 1950: Donald Hamilton McLaughlin
* 1951: Willis McGerald Peirce
* 1952: Michael Lawrence Haider
* 1953: Andrew Fletcher
* 1954: Leo Frederick Reinartz
* 1955: Henry DeWitt Smith
* 1956: Carl Ernest Reistle Jr.
* 1957: Grover Justine Holt
* 1958: Augustus Braun Kinzel
* 1959: Howard Carter Pyle
* 1960: Joseph Lincoln Gillson
* 1961: Ronald Russel McNaughton
* 1962: Lloyd E. Elkins
* 1963: Roger Vern Pierce
* 1964: Karl Leroy Fetters
* 1965: Thomas Corwin Frick
* 1966: William Bishop Stephenson
* 1967: Walter R. Hibbard Jr.
* 1968: John Robertson McMillan
* 1969: James Boyd
* 1970: John C. Kinnear
* 1971: John Smith Bell
* 1972: Dennis L. McElroy
* 1973: James B. Austin
* 1974: Wayne E. Glenn
* 1975: James D. Reilly
* 1976: Julius J. Harwood
* 1977: H. Arthur Nedom
* 1978: Wayne L. Dowdey
* 1979: William H. Wise
* 1980: M. Scott Kraemer
* 1981: Robert H. Merrill
* 1982: Harold W. Paxton
* 1983: Edward E. Runyan
* 1984: Nelson Severinghaus, Jr.
* 1985: Norman T. Mills
* 1986: Arlen L. Edgar
* 1987: Alan Lawley
* 1988: Thomas V. Falkie
* 1989: Howard N. Hubbard, Jr.
* 1990: Donald G. Russell
* 1991: Milton E. Wadsworth
* 1992: Roshan B. Bhappu
* 1993: G. Hugh Walker
* 1994: Noel D. Rietman
* 1995: Frank V. Nolfi, Jr.
* 1996: Donald W. Gentry
* 1997: Leonard G. Nelson
* 1998: Roy H. Koerner
* 1999: Paul G. Campbell, Jr.
* 2000: Robert E. Murray
* 2001: Grant P. Schneider
* 2002: George H. Sawyer
* 2003: Robert H. Wagoner
* 2004: Robert C. Freas
* 2005: Alan W. Cramb
* 2006: James R. Jorden
* 2007: Dan J. Thoma
* 2008: Michael Karmis
* 2009: Ian Sadler
* 2010: DeAnn Craig
* 2011: Brajendra Mishra
* 2012: George W. Luxbacher
* 2013: Dale Heinz
* 2014: Behrooz Fattahi
* 2015: Garry W. Warren
* 2016: Nikhil Trivedi
* 2017: John G. Speer | 0 | Metallurgy |
In 2020 scientists showed, with an experiment with different gravity environments on the ISS, that microorganisms could be employed to mine useful elements from basaltic rocks via bioleaching in space. | 0 | Metallurgy |
Stainless steel alloys remain a research target because of lower production costs, as well as the need for an austenitic stainless steel with high-temperature corrosion resistance in environments with water vapor. Research focuses on increasing high-temperature tensile strength, toughness, and creep resistance to compete with Ni-based superalloys.
Oak Ridge National Laboratory is researching austenitic alloys, achieving similar creep and corrosion resistance at 800 °C to that of other austenitic alloys, including Ni-based superalloys. | 0 | Metallurgy |
Flowers of sulfur (FOS) testing was developed to determine the porosity of metallic coatings susceptible to sulfur induced corrosion [see below ASTM B809-95(2018)]. Applicable substrates are silver, copper, copper alloys and any other metal or metal alloy with which sulfur will react. For porosity testing, coatings can be single or multiple layers of any metal that is not corroded and sealed by a self-limiting reaction in the reducing sulfur environment of the FOS test. The simplest recommended technique is to identify any porosity of the coating as revealed by the presence of surface spots. These surface spots form where the environmental sulfur has penetrated and reacted with the base metal, producing a metal sulfide. Chalcocite, copper (I) sulfide is dark-grey to black. Silver (I) sulfide is also grey-black.
The adoption of lead-free solders and lead-free soldering motivated the further development and application of immersion silver plating. Immersion silver improves wettability and solderability. Mixed flowing gas testing failed to alert the electronics manufacturing industry to weaknesses in immersion silver plating (for example, see Reference 7). This furthered the application of FOS. In particular, it was determined that moist, high-sulfur environments facilitated creep corrosion. The development of FOS testing for creep corrosion was furthered by efforts under the auspices of the International Electronics Manufacturing Initiative (INEMI) and the Surface Mount Technology Association (SMTA) by Haley Fu, et al. and Prabjit Singh et al. MFG testing also proved unreliable for high-sulfur environmental testing of chip resistors and their certification as sulfur resistant. There has been recent development in utilizing FOS testing for porosity of conformal coatings.
The material under test is suspended inside a container over a source of powdered sulfur. The powdered sulfur is placed in a dish. The temperature and internal humidity of the container are regulated. Temperature is typically controlled by placing the container in a constant temperature oven. Humidity inside the container is typically controlled with a saturated salt solution whose vapor pressure is well characterized at the temperature of the test. Saturated potassium nitrate solution is standard practice for humidity control in humid sulfur vapor testing. The saturated salt solution is placed physically outside of the sulfur containing dish. The sulfur containing dish may “float” in the saturated salt solution. The dish should provide an ample, available powdered sulfur surface.
Recommended materials for the test chamber are glass and acrylic. The materials under test must be suspended or supported above the saturated salt solution. Suspension materials are also recommended fabricated from glass or plastic. Frames made out of 316 stainless steel have seen use for hanging specimens. Monofilament line has been used for hanging objects under test. Recommended specimen placement is at least 75 mm from the surfaces of the sulfur and the saturated salt solutions, at least 25 mm from all internal vessel surfaces and at least 10 mm spacing from specimen to specimen.
Standard test procedures call for performing the specimen exposure at 50 °C for at least 24 hours. Activity of the sulfur and its products with humid air increase with temperature. Exposure periods can be extended into the week range. Decisions on length of exposure is commonly motivated by observations from shorter-term tests. Standard procedure calls for equilibrating the test chamber at temperature and relative humidity before inserting the test specimens.
Porosity results are determined by the distribution, number and sizes of dark spots on the materials under test. Again, the dark spots are due to reaction of the moist sulfur vapors with the underlying silver or copper material. One may choose to include silver or both silver and copper reference coupons into the humid sulfur test. The accumulation of copper(I) sulfate and silver (I) sulfate deposits on the coupons, determined by weight change, allows comparisons to ISA 71.04 severity levels for mixed flowing gas testing. | 0 | Metallurgy |
PGC-1α is a gene that contains two promoters, and has 4 alternative splicings. PGC-1α is a transcriptional coactivator that regulates the genes involved in energy metabolism. It is the master regulator of mitochondrial biogenesis. This protein interacts with the nuclear receptor PPAR-γ, which permits the interaction of this protein with multiple transcription factors. This protein can interact with, and regulate the activity of, cAMP response element-binding protein (CREB) and nuclear respiratory factors (NRFs) . PGC-1α provides a direct link between external physiological stimuli and the regulation of mitochondrial biogenesis, and is a major factor causing slow-twitch rather than fast-twitch muscle fiber types.
Endurance exercise has been shown to activate the PGC-1α gene in human skeletal muscle. Exercise-induced PGC-1α in skeletal muscle increases autophagy and unfolded protein response.
PGC-1α protein may also be involved in controlling blood pressure, regulating cellular cholesterol homeostasis, and the development of obesity. | 1 | Gene expression + Signal Transduction |
This method is an acid heap leaching method like that of the copper method in that it utilises sulfuric acid instead of cyanide solution to dissolve the target minerals from crushed ore. The amount of sulfuric acid required is much higher than for copper ores, as high as 1,000 kg of acid per tonne of ore, but 500 kg is more common. The method was originally patented by Australian miner BHP and is being commercialized by Cerro Matoso in Colombia, a wholly owned subsidiary of BHP; Vale in Brazil; and European Nickel for the rock laterite deposits of Turkey, Talvivaara mine in Finland, the Balkans, and the Philippines. There currently are no operating commercial scale nickel laterite heap leach operations, but there is a sulphide HL operating in Finland.
Nickel recovery from the leach solutions is much more complex than for copper and requires various stages of iron and magnesium removal, and the process produces both leached ore residue ("ripios") and chemical precipitates from the recovery plant (principally iron oxide residues, magnesium sulfate and calcium sulfate) in roughly equal proportions. Thus, a unique feature of nickel heap leaching is the need for a tailings disposal area.
The final product can be nickel hydroxide precipitates (NHP) or mixed metal hydroxide precipitates (MHP), which are then subject to conventional smelting to produce metallic nickel. | 0 | Metallurgy |
Utilitarian objects; objects of personal adornment
#Casas Grandes, Chihuahua
#Chalchihuites, Zacatecas
#Hervideros, Durango
#La Quemada, Zacatecas
#Navocoyán, Durango
#Chihuahua, Chihuahua
#Schroeder site, Durango
#Venis Meicis, San Luis Potosí
#Zape, Durango
#Babicora, Chihuahua
#Rancho San Miguiel, Chihuahua
#Santa Maria R., Chihuahua | 0 | Metallurgy |
The tetrathionate anion, , is a sulfur oxyanion derived from the compound tetrathionic acid, HSO. Two of the sulfur atoms present in the ion are in oxidation state 0 and two are in oxidation state +5. Alternatively, the compound can be viewed as the adduct resulting from the binding of disulfide| to SO. Tetrathionate is one of the polythionates, a family of anions with the formula [S(SO)]. Its IUPAC name is 2-(dithioperoxy)disulfate, and the name of its corresponding acid is 2-(dithioperoxy)disulfuric acid. The Chemical Abstracts Service identifies tetrathionate by the CAS Number 15536-54-6. | 0 | Metallurgy |
Roasting is a process of oxidizing zinc sulfide concentrates at high temperatures into an impure zinc oxide, called "Zinc Calcine". The chemical reactions that take place are as follows:
Approximately 90% of zinc in concentrates are oxidized to zinc oxide. However, at the roasting temperatures around 10% of the zinc reacts with the iron impurities of the zinc sulfide concentrates to form zinc ferrite. A byproduct of roasting is sulfur dioxide, which is further processed into sulfuric acid, a commodity. The linked refinery flow sheet shows a schematic of Noranda's eastern Canadian zinc roasting operation
The process of roasting varies based on the type of roaster used. There are three types of roasters: multiple-hearth, suspension, and fluidized-bed. | 0 | Metallurgy |
As the 5′ UTR has high GC content, secondary structures often occur within it. Hairpin loops are one such secondary structure that can be located within the 5′ UTR. These secondary structures also impact the regulation of translation. | 1 | Gene expression + Signal Transduction |
Non-receptor tyrosine-protein kinase TYK2 is an enzyme that in humans is encoded by the TYK2 gene.
TYK2 was the first member of the JAK family that was described (the other members are JAK1, JAK2, and JAK3). It has been implicated in IFN-α, IL-6, IL-10 and IL-12 signaling. | 1 | Gene expression + Signal Transduction |
The Castner process for production of sodium metal was introduced in 1888 by Hamilton Castner. At that time (prior to the introduction in the same year of the Hall-Héroult process) the primary use for sodium metal was as a reducing agent to produce aluminium from its purified ores. The Castner process reduced the cost of producing sodium in comparison to the old method of reducing sodium carbonate at high temperature using carbon. This in turn reduced the cost of producing aluminium, although the reduction-by-sodium method still could not compete with Hall-Héroult. The Castner process continued nevertheless due to Castner's finding new markets for sodium. In 1926, the Downs cell replaced the Castner process. | 0 | Metallurgy |
In the late 1840s, the German chemist developed a modification of the puddling process to produce not iron but steel at the Haspe Iron Works in Hagen; it was subsequently commercialized in Germany, France and the UK in the 1850s, and puddled steel was the main raw material for Krupp cast steel even in the 1870s. Before the development of the basic refractory lining (with magnesium oxide, MgO) and the wide-scale adoption of the Gilchrist–Thomas process ca. 1880 it complemented acidic Bessemer converters (with a refractory material made of ) and open hearths because unlike them, the puddling furnace could utilize phosphorous ores abundant in Continental Europe. | 0 | Metallurgy |
Magnesium is anodized primarily as a primer for paint. A thin (5 μm) film is sufficient for this. Thicker coatings of 25 μm and up can provide mild corrosion resistance when sealed with oil, wax, or sodium silicate. Standards for magnesium anodizing are given in AMS 2466, AMS 2478, AMS 2479, and ASTM B893. | 0 | Metallurgy |
The officers of the IDDRG are the current President, Vice-Presidents, General Secretary, Treasurer, and active Past-Presidents. The officers of the IDDRG comprise the Executive Committee. The vice-presidents are selected for their expertise and to represent, as far as possible, the geographic distribution of the member countries. Specific responsibilities of vice-presidents are to contact and represent the National delegations in their geographic area and to chair technical sessions at conferences. | 0 | Metallurgy |
Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BC, Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands, Spain, Macedonia, Africa, Asia Minor, Syria and Greece; by the end of the Emperor Trajan's reign, the Roman Empire had grown further to encompass parts of Britain, Egypt, all of modern Germany west of the Rhine, Dacia, Noricum, Judea, Armenia, Illyria, and Thrace (Shepard 1993). As the empire grew, so did its need for metals.
Central Italy itself was not rich in metal ores, leading to necessary trade networks in order to meet the demand for metal. Early Italians had some access to metals in the northern regions of the peninsula in Tuscany and Cisalpine Gaul, as well as the islands Elba and Sardinia. With the conquest of Etruria in 275 BC and the subsequent acquisitions due to the Punic Wars, Rome had the ability to stretch further into Transalpine Gaul and Iberia, both areas rich in minerals. At the height of the Empire, Rome exploited mineral resources from Tingitana in north western Africa to Egypt, Arabia to North Armenia, Galatia to Germania, and Britannia to Iberia, encompassing all of the Mediterranean coast. Britannia, Iberia, Dacia, and Noricum were of special significance, as they were very rich in deposits and became major sites of resource exploitation (Shepard, 1993).
There is evidence that after the middle years of the Empire there was a sudden and steep decline in
mineral extraction. This was mirrored in other trades and industries.
One of the most important Roman sources of information is the Naturalis Historia of Pliny the Elder. Several books (XXXIII–XXXVII) of his encyclopedia cover metals and metal ores, their occurrence, importance and development. | 0 | Metallurgy |
T. H. Henry analyzed and recorded the composition of wootz steel samples provided by the Royal School of Mines. Recording:
*Carbon (Combined) 1.34%
* Carbon (Uncombined) 0.31%
* Sulfur 0.17%
* Silicon 0.04%
* Arsenic 0.03%
Wootz steel was analyzed by Michael Faraday and recorded to contain 0.01-0.07% aluminium. Faraday, Messrs (et al.), and Stodart hypothesized that aluminium was needed in the steel and was important in forming the excellent properties of wootz steel. However T. H. Henry deduced that presence of aluminium in the Wootz used by these studies was due to slag, forming as silicates. Percy later reiterated that the quality of wootz steel does not depend on the presence of aluminium. | 0 | Metallurgy |
In materials science, an interstitial defect is a type of point crystallographic defect where an atom of the same or of a different type, occupies an interstitial site in the crystal structure. When the atom is of the same type as those already present they are known as a self-interstitial defect. Alternatively, small atoms in some crystals may occupy interstitial sites, such as hydrogen in palladium. Interstitials can be produced by bombarding a crystal with elementary particles having energy above the displacement threshold for that crystal, but they may also exist in small concentrations in thermodynamic equilibrium. The presence of interstitial defects can modify the physical and chemical properties of a material. | 0 | Metallurgy |
* King Chandra and the Mehrauli Pillar, M.C. Joshi, S.K. Gupta and Shankar Goyal, Eds., Kusumanjali Publications, Meerut, 1989.
* The Rustless Wonder – A Study of the Iron Pillar at Delhi, T.R. Anantharaman, Vigyan Prasar New Delhi, 1996.
* Delhi Iron Pillar: New Insights. R. Balasubramaniam, Aryan Books International, Delhi, and Indian Institute of Advanced Study, Shimla, 2002, Hardbound, . [http://www.infinityfoundation.com/mandala/t_rv/t_rv_agraw_delhi_frameset.htm] [http://home.iitk.ac.in/~bala/journalpaper/journal/index.htm]
* The Delhi Iron Pillar: Its Art, Metallurgy and Inscriptions, M.C. Joshi, S.K. Gupta and Shankar Goyal, Eds., Kusumanjali Publications, Meerut, 1996.
* The World Heritage Complex of the Qutub, R. Balasubramaniam, Aryan Books International, New Delhi, 2005, Hardbound, .
* "Delhi Iron Pillar" (in two parts), R. Balasubramaniam, IIM Metal News Volume 7, No. 2, April 2004, pp. 11–17 and IIM Metal News Volume 7, No. 3, June 2004, pp. 5–13. [http://home.iitk.ac.in/%7Ebala/journalpaper/popart_6_7/metalnews_2004.pdf]
* [http://home.iitk.ac.in/%7Ebala/journalpaper/journal/journalpaper_20.pdf New Insights on the 1600-Year Old Corrosion Resistant Delhi Iron Pillar], R. Balasubramaniam, Indian Journal of History of Science 36 (2001) 1–49.
* The Early use of Iron in India, Dilip K. Chakrabarti, Oxford University Press, New Delhi, 1992, . | 0 | Metallurgy |
Lower bainite forms between 250 and 400 °C and takes a more plate-like form than upper bainite. There are not nearly as many low angle boundaries between laths in lower bainite. In lower bainite, the habit plane in ferrite will also shift from <111> towards <110> as transformation temperature decreases. In lower bainite, cementite nucleates on the interface between ferrite and austenite. | 0 | Metallurgy |
The Gilchrist–Thomas process or Thomas process is a historical process for refining pig iron, derived from the Bessemer converter. It is named after its inventors who patented it in 1877: Percy Carlyle Gilchrist and his cousin Sidney Gilchrist Thomas. By allowing the exploitation of phosphorous iron ore, the most abundant, this process allowed the rapid expansion of the steel industry outside the United Kingdom and the United States.
The process differs essentially from the Bessemer process in the refractory lining of the converter. The latter, being made of dolomite fired with tar, is basic, whereas the Bessemer lining, made of packed sand, is acidic. Phosphorus, by migrating from iron to slag, allows both the production of a metal of satisfactory quality, and of phosphates sought after as fertilizer, known as "Thomas meal". The disadvantages of the basic process includes larger iron loss and more frequent relining.
After having favored the spectacular growth of the Lorraine iron and steel industry, the process progressively faded away in front of the Siemens-Martin open hearth, which also used the benefit of basic refractory lining, before disappearing in the mid-1960s: with the development of gas liquefaction, the use of pure oxygen became economically viable. Even if modern pure oxygen converters all operate with a basic medium, their performance and operation have little to do with their ancestor. | 0 | Metallurgy |
pRb acts as a recruiter that allows for the binding of proteins that alter chromatin structure onto the site E2F-regulated promoters. Access to these E2F-regulated promoters by transcriptional factors is blocked by the formation of nucleosomes and their further packing into chromatin. Nucleosome formation is regulated by post-translational modifications to histone tails. Acetylation leads to the disruption of nucleosome structure. Proteins called histone acetyltransferases (HATs) are responsible for acetylating histones and thus facilitating the association of transcription factors on DNA promoters. Deacetylation, on the other hand, leads to nucleosome formation and thus makes it more difficult for transcription factors to sit on promoters. Histone deacetylases (HDACs) are the proteins responsible for facilitating nucleosome formation and are therefore associated with transcriptional repressors proteins.
pRb interacts with the histone deacetylases HDAC1 and HDAC3. pRb binds to HDAC1 in its pocket domain in a region that is independent to its E2F-binding site. pRb recruitment of histone deacetylases leads to the repression of genes at E2F-regulated promoters due to nucleosome formation. Some genes activated during the G1/S transition such as cyclin E are repressed by HDAC during early to mid-G1 phase. This suggests that HDAC-assisted repression of cell cycle progression genes is crucial for the ability of pRb to arrest cells in G1. To further add to this point, the HDAC-pRb complex is shown to be disrupted by cyclin D/Cdk4 which levels increase and peak during the late G1 phase. | 1 | Gene expression + Signal Transduction |
MicroRNAs (miRNAs) are small RNAs that typically are partially complementary to sequences in metazoan messenger RNAs. Binding of a miRNA to a message can repress translation of that message and accelerate poly(A) tail removal, thereby hastening mRNA degradation. The mechanism of action of miRNAs is the subject of active research. | 1 | Gene expression + Signal Transduction |
Green death is a solution used to test the resistance of metals and alloys to corrosion. It consists of a mixture of sulfuric acid, hydrochloric acid, iron(III) chloride and copper(II) chloride and its boiling point is at approximately 103 °C. Its typical chemical composition is given in the table hereafter:
The chemical composition of the green death solution allows it to achieve a particularly aggressive oxidizing chloride solution. Indeed, among the four reagents, all are oxidizing species (, , ) except hydrochloric acid (HCl) in which the chlorine atom is present in its lowest oxidation state as anion. The chloride anions, also added to the solution as counter-ions of iron(III) and copper(II) species, are very aggressive for the localized corrosion of metals and alloys as they induce severe pitting corrosion problems. The green death solution is also used to determine the critical pitting temperature (CPT) and the critical crevice temperature (CCT) of metals and alloys. | 0 | Metallurgy |
SLC18A2 is believed to possess at least two distinct binding sites, which are characterized by tetrabenazine (TBZ) and reserpine binding to the transporter. Amphetamine (TBZ site) and methamphetamine (reserpine site) bind at distinct sites on SLC18A2 to inhibit its function. SLC18A2 inhibitors like tetrabenazine and reserpine reduce the concentration of monoamine neurotransmitters in the synaptic cleft by inhibiting uptake through SLC18A2; the inhibition of SLC18A2 uptake by these drugs prevents the storage of neurotransmitters in synaptic vesicles and reduces the quantity of neurotransmitters that are released through exocytosis. Although many substituted amphetamines induce the release of neurotransmitters from vesicles through SLC18A2 while inhibiting uptake through SLC18A2, they may facilitate the release of monoamine neurotransmitters into the synaptic cleft by simultaneously reversing the direction of transport through the primary plasma membrane transport proteins for monoamines (i.e., the dopamine transporter, norepinephrine transporter, and serotonin transporter) in monoamine neurons. Other SLC18A2 inhibitors such as GZ-793A inhibit the reinforcing effects of methamphetamine, but without producing stimulant or reinforcing effects themselves.
Researchers have found that inhibiting the dopamine transporter (but not SLC18A2) will block the effects of amphetamine and cocaine; while, in another experiment, observing that disabling SLC18A2 (but not the dopamine transporter) prevents any notable action in test animals after amphetamine administration yet not cocaine administration. This suggests that amphetamine may be an atypical substrate with little to no ability to prevent dopamine reuptake via binding to the dopamine transporter but, instead, uses it to enter a neuron where it then interacts with SLC18A2 to induce efflux of dopamine from their vesicles into the cytoplasm whereupon dopamine transporters with amphetamine substrates attached move this recently liberated dopamine into the synaptic cleft. | 1 | Gene expression + Signal Transduction |
Exfoliation (or onion skin weathering) is the gradual removing of spall due to the cyclic increase and decrease in the temperature of the surface layers of the rock. Rocks do not conduct heat well, so when they are exposed to extreme heat, the outermost layer becomes much hotter than the rock underneath causing differential thermal expansion. This differential expansion causes sub-surface shear stress, in turn causing spalling. Extreme temperature change, such as forest fires, can also cause spalling of rock. This mechanism of weathering causes the outer surface of the rock to fall off in thin fragments, sheets or flakes, hence the name exfoliation or onion skin weathering. | 0 | Metallurgy |
(Note that COX1, COX2, and COX3 are mitochondrially encoded)
*COX4I1 001861
*COX5B NM_001862
*COX6B1 NM_001863
*COX6C NM_004374
*COX7A2 NM_001865 Homo sapiens cytochrome c oxidase subunit VIIa polypeptide 2 (liver) (COX7A2),
*COX7A2L NM_004718
*COX7C NM_001867
*COX8
*COX8A NM_004074 Homo sapiens cytochrome c oxidase subunit VIII (COX8), nuclear gene encoding
*COX11 NM_004375
*COX14 NM_032901
*COX15 NM_004376
*COX16 NM_016468
*COX19 NM_001031617
*COX20 NM_198076
*CYC1 Homo sapiens cytochrome c-1 (CYC1)
*UQCC NM_018244 Required for the assembly of the ubiquinol-cytochrome c reductase complex (mitochondrial respiratory chain complex III or cytochrome b-c1 complex)
*UQCR10 NM_013387
*UQCR11 NM_006830 Homo sapiens ubiquinol-cytochrome c reductase (6.4kD) subunit (UQCR), mRNA
*UQCRB NM_006294
*UQCRC1 NM_003365 Homo sapiens ubiquinol-cytochrome c reductase core protein I (UQCRC1), mRNA
*UQCRC2 NM_003366
*UQCRHL NM_001089591
*UQCRQ NM_014402 Homo sapiens low molecular mass ubiquinone-binding protein (9.5kD) (QP-C), mRNA | 1 | Gene expression + Signal Transduction |
PKA has always been considered important in formation of a memory. In the fruit fly, reductions in expression activity of DCO (PKA catalytic subunit encoding gene) can cause severe learning disabilities, middle term memory and short term memory. Long term memory is dependent on the CREB transcription factor, regulated by PKA. A study done on drosophila reported that an increase in PKA activity can affect short term memory. However, a decrease in PKA activity by 24% inhibited learning abilities and a decrease by 16% affected both learning ability and memory retention. Formation of a normal memory is highly sensitive to PKA levels. | 1 | Gene expression + Signal Transduction |
SH2 domains are not present in yeast and appear at the boundary between protozoa and animalia in organisms such as the social amoeba Dictyostelium discoideum.
A detailed bioinformatic examination of SH2 domains of human and mouse reveals 120 SH2 domains contained within 115 proteins encoded by the human genome, representing a rapid rate of evolutionary expansion among the SH2 domains.
A large number of SH2 domain structures have been solved and many SH2 proteins have been knocked out in mice. | 1 | Gene expression + Signal Transduction |
The history of metallurgy in the Urals stands out to historians and economists as a separate stage in the history of Russian industry and covers the period from the 4th millennium BC to the present day. The emergence of the mining district is connected with the history of Ural metallurgy. The geography of the Ural metallurgy covers the territories of modern Perm Krai, Sverdlovsk Oblast, Udmurtia, Bashkortostan, Chelyabinsk Oblast and Orenburg Oblast.
In the 18th century, periods of formation and development of industrial metallurgical centers stand out in Urals metallurgy, for example, the rapid construction and economic growth of more than two hundred metallurgy factories during the 18th to the first half of the 19th centuries until the abolition of serfdom on February 19, 1861 in the Russian Empire, which led to reductions in the labor force. There was also a sharp drop in production rates in the early 1900s but that was followed by recovery and growth by 1913. In the 20th century, after recovering from the decline caused by the Russian Revolution(s): 1905, February 1917, and October 1917 and the Russian Civil War (November 1917 - June 1923), Ural metallurgy had a strategic impact on ensuring the defense of the USSR on the Eastern Front of World War II which is known in Russia as the Great Patriotic War. In the 21st century, the development of metallurgical enterprises in the Urals is associated with the formation of vertically integrated full cycle companies.
The main milestones in the development of metal production technologies in the Urals include the transition from bloomery or the old iron production method to the Kontuazsky forge (for remelting heavy scrap) and the puddling method in the second half of the 19th century. Later, there was the development of hot blast at the end of the 19th century. Further, there was a transition to coke fuel and the introduction of steam engines. Finally, there was the development of open-hearth and Bessemer methods of steel production at the beginning of the 20th century. | 0 | Metallurgy |
While tubulin and related structural proteins also bind and hydrolyze GTP as part of their function to form intracellular tubules, these proteins utilize a distinct tubulin domain that is unrelated to the G domain used by signaling GTPases.
There are also GTP-hydrolyzing proteins that use a P-loop from a superclass other than the G-domain-containg one. Examples include the NACHT proteins of its own superclass and McrB protein of the AAA+ superclass. | 1 | Gene expression + Signal Transduction |
A DNA-gelatin mixture may be used for printing onto a slide. Gelatin powder is first dissolved in sterile Milli-Q water to form a 0.2% gelatin solution. Purified DNA plasmid is then mixed with the gelatin solution, and the final gelatin concentration is kept greater than 0.17%. Besides gelatin, atelocollagen and fibronectin are also successful transfection vectors for introducing foreign DNA into the cell nucleus. | 1 | Gene expression + Signal Transduction |
The voltage (electromotive force E) produced by a galvanic cell can be estimated from the standard Gibbs free energy change in the electrochemical reaction according to:
where ν is the number of electrons transferred in the balanced half reactions, and F is Faradays constant. However, it can be determined more conveniently by the use of a standard potential table for the two half cells involved. The first step is to identify the two metals and their ions reacting in the cell. Then one looks up the standard electrode potential, E, in volts, for each of the two half reactions. The standard potential of the cell is equal to the more positive E value minus the more negative E' value.
For example, in the figure above the solutions are CuSO and ZnSO. Each solution has a corresponding metal strip in it, and a salt bridge or porous disk connecting the two solutions and allowing ions to flow freely between the copper and zinc solutions. To calculate the standard potential one looks up copper and zinc's half reactions and finds:
:Cu + 2 Cu E = +0.34 V
:Zn + 2 Zn E = −0.76 V
Thus the overall reaction is:
:Cu + Zn Cu + Zn
The standard potential for the reaction is then +0.34 V − (−0.76 V) = 1.10 V. The polarity of the cell is determined as follows. Zinc metal is more strongly reducing than copper metal because the standard (reduction) potential for zinc is more negative than that of copper. Thus, zinc metal will lose electrons to copper ions and develop a positive electrical charge. The equilibrium constant, K, for the cell is given by:
where F is the Faraday constant, R is the gas constant and T is the temperature in kelvins. For the Daniell cell K is approximately equal to . Thus, at equilibrium, a few electrons are transferred, enough to cause the electrodes to be charged.
Actual half-cell potentials must be calculated by using the Nernst equation as the solutes are unlikely to be in their standard states:
where Q is the reaction quotient. When the charges of the ions in the reaction are equal, this simplifies to:
where {M} is the activity of the metal ion in solution. In practice concentration in mol/L is used in place of activity. The metal electrode is in its standard state so by definition has unit activity. The potential of the whole cell is obtained as the difference between the potentials for the two half-cells, so it depends on the concentrations of both dissolved metal ions. If the concentrations are the same, and the Nernst equation is not needed under the conditions assumed here.
The value of 2.303 is , so at 25 °C (298.15 K) the half-cell potential will change by only 0.05918 V/ν if the concentration of a metal ion is increased or decreased by a factor of 10.
These calculations are based on the assumption that all chemical reactions are in equilibrium. When a current flows in the circuit, equilibrium conditions are not achieved and the cell voltage will usually be reduced by various mechanisms, such as the development of overpotentials. Also, since chemical reactions occur when the cell is producing power, the electrolyte concentrations change and the cell voltage is reduced. A consequence of the temperature dependency of standard potentials is that the voltage produced by a galvanic cell is also temperature dependent. | 0 | Metallurgy |
Calcium ions (Ca) contribute to the physiology and biochemistry of organisms' cells. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, in contraction of all muscle cell types, and in fertilization. Many enzymes require calcium ions as a cofactor, including several of the coagulation factors. Extracellular calcium is also important for maintaining the potential difference across excitable cell membranes, as well as proper bone formation.
Plasma calcium levels in mammals are tightly regulated, with bone acting as the major mineral storage site. Calcium ions, Ca, are released from bone into the bloodstream under controlled conditions. Calcium is transported through the bloodstream as dissolved ions or bound to proteins such as serum albumin. Parathyroid hormone secreted by the parathyroid gland regulates the resorption of Ca from bone, reabsorption in the kidney back into circulation, and increases in the activation of vitamin D to calcitriol. Calcitriol, the active form of vitamin D, promotes absorption of calcium from the intestines and bones. Calcitonin secreted from the parafollicular cells of the thyroid gland also affects calcium levels by opposing parathyroid hormone; however, its physiological significance in humans is dubious.
Intracellular calcium is stored in organelles which repetitively release and then reaccumulate Ca ions in response to specific cellular events: storage sites include mitochondria and the endoplasmic reticulum.
Characteristic concentrations of calcium in model organisms are: in E. coli 3mM (bound), 100nM (free), in budding yeast 2mM (bound), in mammalian cell 10-100nM (free) and in blood plasma 2mM. | 1 | Gene expression + Signal Transduction |
GPR126 is necessary for Schwann cell myelination. Knockouts of this adhesion GPCR in both Danio rerio and Mus musculus result in an arrest at the promyelinating stage. Schwann cells arise from the neural crest, which migrates to peripheral nerves to form either myelinating or non-myelinating cells. In GPR126 knockouts, these precursor cells develop to the promyelinating stage, where they have wrapped approximately 1.5 times. Myelination is arrested at the promyelinating stage and in fish no myelin basic protein can be detected. In fish this can be rescued by adding forskolin during development, which rescues myelin basic protein expression. | 1 | Gene expression + Signal Transduction |
First developed in 1836 by Danish archaeologist Christian Jürgensen Thomsen as a part of his "Three-age system", the term "Bronze Age" is used by archaeologists to refer to those societies which have developed bronze technology but not yet learned how to work the more complicated process involved in making iron objects. The European Bronze Age lasted from , when the Aegean civilizations of Greece first developed bronze technology, right through to , when the Nordic Bronze Age came to an end with the development of iron among Scandinavian communities.
The period known by archaeologists as Bronze Age Britain lasted from through to , and was defined by the adoption of copper and bronze technologies on the island. Bronze Age Ireland followed a similar, yet distinct course.
The Early Bronze Age in the British Isles was marked by the adoption of what archaeologists call the "Beaker culture", which had arrived from continental Europe. Eogan noted that the "evidence from archaeology is that Beaker-using communities were the earliest metallurgists in Britain and Ireland", with their produce including "copper artefacts such as tanged daggers but also gold objects as well as the use of gold for embellishment." | 0 | Metallurgy |
The geographical location of the explorations in southern Turkmenistan were not marked with precision. The Merv Oasis is one of the regions explored by Soviet archeologists of the YuTAKE; Antiochia is the primary site in this oasis. Namazgtepe (tepe means "hill") is 100–120 kilometers from Ashgabat in Turkmenistan at the border with Iran, southeast of the Caspian Sea. Excavations at this site have provided a chronological approach for Central Asia. Namazga-Tepewas the largest settlement found in the Kopetdag foothills, a range of hills extending up to the border with Iran. | 0 | Metallurgy |
In eukaryotic organisms, pre-mRNA is transcribed in the nucleus, introns are spliced out, then the mature mRNA is exported from the nucleus to the cytoplasm. The small subunit of the ribosome usually starts by binding at the 5 end of the mRNA and is joined there by various other eukaryotic initiation factors, forming the initiation complex. The initiation complex scans along the mRNA strand until it reaches a start codon, and then the large subunit of the ribosome attaches to the small subunit and translation of a protein begins. This entire process is referred to as gene expression; it is the process by which the information in a gene, encoded as a sequence of bases in DNA, is converted into the structure of a protein. A Morpholino can modify splicing, block translation, or block other functional sites on RNA depending on the Morpholinos base sequence. | 1 | Gene expression + Signal Transduction |
The blister copper is put into an anode furnace, a furnace that refines the blister copper to anode-grade copper in two stages by removing most of the remaining sulfur and iron, and then removing oxygen introduced during the first stage. This second stage, often referred to as poling is done by blowing natural gas, or some other reducing agent, through the molten copper oxide. When this flame burns green, indicating the copper oxidation spectrum, the oxygen has mostly been burned off. This creates copper at about 99% pure. | 0 | Metallurgy |
The Ellingham curve for aluminium lies below the curves of most metals such as chromium, iron, etc. This fact indicates that aluminium can be used as the reducing agent for oxides of all these metals. This result is illustrated as follows:
The free energies of formation of chromium(III) oxide and aluminium oxide per mole of oxygen consumed are -541 kJ and -827 kJ respectively. The processes are:
The second equation minus the first equation gives:
So aluminium oxide is more stable than chromium oxide (at least at normal temperatures, and in fact all the way up to the decomposition temperatures of the oxides). Since the Gibbs free energy change is negative, aluminium can reduce chromium oxide.
In pyrometallurgy, aluminium is used as a reducing agent in the alumino-thermic process or thermite process to extract chromium and manganese by reduction of their oxides. | 0 | Metallurgy |
The purpose of this method is to reduce carbon content from steel. This process is suitable for secondary steelmaking industry which recycling steel scrap that has variety of carbon content in their feedstock. This method aim to replace current conventional method that utilizing Basic Oxygen Furnace (BOF) to reduce carbon content of iron by blowing oxygen to make it react with carbon and forming CO.
In electrorefining, decarburization process happened in electrochemical cell that composed of inert electrode, slag and steel. During the process, current passing through the cell and made slag and steel melted. Oxygen ion from slag decompose and oxidize carbon on steel and to form CO. That decarburizing reaction is occurred in three steps as follow. (ads) means adsorbed intermediate
The total reaction from this cell is following this scheme
The SiO is come from the slag, based on the reaction above, beside producing CO gas, this method also producing pure silicon (depending on the slag). The benefit of this direct decarburization process is it does not produce CO but CO which is not considered as greenhouse gas. | 0 | Metallurgy |
Small GTPases function as monomers and have a molecular weight of about 21 kilodaltons that consists primarily of the GTPase domain. They are also called small or monomeric guanine nucleotide-binding regulatory proteins, small or monomeric GTP-binding proteins, or small or monomeric G-proteins, and because they have significant homology with the first-identified such protein, named Ras, they are also referred to as Ras superfamily GTPases. Small GTPases generally serve as molecular switches and signal transducers for a wide variety of cellular signaling events, often involving membranes, vesicles or cytoskeleton. According to their primary amino acid sequences and biochemical properties, the many Ras superfamily small GTPases are further divided into five subfamilies with distinct functions: Ras, Rho ("Ras-homology"), Rab, Arf and Ran. While many small GTPases are activated by their GEFs in response to intracellular signals emanating from cell surface receptors (particularly growth factor receptors), regulatory GEFs for many other small GTPases are activated in response to intrinsic cell signals, not cell surface (external) signals. | 1 | Gene expression + Signal Transduction |
Solvent extraction and electrowinning (SX/EW) is a two-stage hydrometallurgical process that first extracts and upgrades copper ions from low-grade leach solutions into a solvent containing a chemical that selectively reacts with and binds the copper in the solvent. The copper is extracted from the solvent with strong aqueous acid which then deposits pure copper onto cathodes using an electrolytic procedure (electrowinning).
SX/EW processing is best known for its use by the copper industry, where it accounts for 20% of worldwide production, but the technology is also successfully applied to a wide range of other metals including cobalt, nickel, zinc and uranium. | 0 | Metallurgy |
The main functions of detonation spray coatings are to protect against corrosion (due to low oxygen content), abrasion and adhesion under low load. This means that detonation spraying produces hard durable coatings that are suitable for:
* Various components of general machinery: shafts, seals, bushings, bearings, seals
* Aviation:
** rotor and stator blades
**engine components
** guide rails
* Oil and gas industry:
** bushings and sealing rings of ESP units
** gate valves
** shut-off valves
** working surface of drill tools
* Space rocket industry
* Electronic and radio industry
* Engineering of instruments
* Tools industry
** Tubular drills
** Skiving knives for rubber and plastic
* Shipbuilding industry
* D-gun plated plug and ring gauges | 0 | Metallurgy |
The Platinum Metal Review journal was established in 1957 and was published by Johnson Mattley and Co. From April 1998, it was published as open access and from the July 2004 issue in electronic format only. In 2014 the name of the journal was changed to Johnson Matthey Technology Review. | 0 | Metallurgy |
Iron was extracted from iron–nickel alloys, which comprise about 6% of all meteorites that fall on the Earth. That source can often be identified with certainty because of the unique crystalline features (Widmanstätten patterns) of that material, which are preserved when the metal is worked cold or at low temperature. Those artifacts include, for example, a bead from the 5th millennium BC found in Iran and spear tips and ornaments from ancient Egypt and Sumer around 4000 BC.
These early uses appear to have been largely ceremonial or decorative. Meteoric iron is very rare, and the metal was probably very expensive, perhaps more expensive than gold. The early Hittites are known to have bartered iron (meteoric or smelted) for silver, at a rate of 40 times the iron's weight, with Assyria in the first centuries of the second millennium BC.
Meteoric iron was also fashioned into tools in the Arctic when the Thule people of Greenland began making harpoons, knives, ulus and other edged tools from pieces of the Cape York meteorite. Typically pea-size bits of metal were cold-hammered into disks and fitted to a bone handle. These artifacts were also used as trade goods with other Arctic peoples: tools made from the Cape York meteorite have been found in archaeological sites more than distant. When the American polar explorer Robert Peary shipped the largest piece of the meteorite to the American Museum of Natural History in New York City in 1897, it still weighed over 33 tons. Another example of a late use of meteoric iron is an adze from around 1000 AD found in Sweden. | 0 | Metallurgy |
This bacterium was previously considered a fish pathogen, but it has recently emerged as a human pathogen. Aeromonas sp. have been isolated from various infected sites from patients (bile, blood, peritoneal fluid, pus, stool and urine). All isolates produced the two principal AHLs, N-butanoylhomoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL). It has been documented that Aeromonas sobria has produced C6-HSL and two additional AHLs with N-acyl side chain longer than C6. | 1 | Gene expression + Signal Transduction |
* ASTM B374-06(2011) — Standard Terminology Relating to Electroplating
* ASTM B542-13 — Standard Terminology Relating to Electrical Contacts and Their Use
* ASTM B735-16 — Standard Test Method for Porosity in Gold Coatings on Metal Substrates by Nitric Acid Vapor
* ASTM B765-03(2018) — Standard Guide for Selection of Porosity and Gross Defect Tests for Electrodeposits and Related Metallic Coatings
* ASTM B798-95(2014) — Standard Test Method for Porosity in Gold or Palladium Coatings on Metal Substrates by Gel-Bulk Electrography
* ASTM B799-95(2014) — Standard Test Method for Porosity in Gold and Palladium Coatings by Sulfurous Acid/Sulfur-Dioxide Vapor
* ASTM B809-95(2018) — Standard Test Method for Porosity in Metallic Coatings by Humid Sulfur Vapor ("Flowers-of-Sulfur")
* ASTM B810-01a (Reapproved 2017) —Standard Method for Calibration of Atmospheric Corrosion Test Chambers by Change in Mass of Copper Coupons
* ANSI/ISA-71.04-2013 Environmental Conditions for Process Measurement and Control Systems: Airborne Contaminants, The International Society of Automation, Research Triangle Park, NC. | 0 | Metallurgy |
In UIT, ultrasonic waves are produced by an electro-mechanical ultrasonic transducer, and applied to a workpiece. An acoustically tuned resonator bar is caused to vibrate by energizing it with a magnetostrictive or Piezoelectric ultrasonic transducer. The energy generated from these high frequency impulses is imparted to the treated surface through the contact of specially designed steel pins. These transfer pins are free to move axially between the resonant body and the treated surface.
When the tool, made up of the ultrasonic transducer, pins and other components, comes into contact with the work piece it acoustically couples with the work piece, creating harmonic resonance. This harmonic resonance is performed at a carefully calibrated frequency, to which metals respond very favorably, resulting in compressive residual stress, stress relief and grain structure improvements.
Depending on the desired effects of treatment a combination of different frequencies and displacement amplitude is applied. Depending on the tool and the Original Equipment Manufacturer, these frequencies range between 15 and 55 kHz, with the displacement amplitude of the resonant body of between . | 0 | Metallurgy |
RNA interference (RNAi) is a natural process used by cells to regulate gene expression. It was discovered in 1998 by Andrew Fire and Craig Mello, who won the Nobel Prize for their discovery in 2006. The process to silence genes first begins with the entrance of a double-stranded RNA (dsRNA) molecule into the cell, which triggers the RNAi pathway. The double-stranded molecule is then cut into small double-stranded fragments by an enzyme called Dicer. These small fragments, which include small interfering RNAs (siRNA) and microRNA (miRNA), are approximately 21–23 nucleotides in length. The fragments integrate into a multi-subunit protein called the RNA-induced silencing complex, which contains Argonaute proteins that are essential components of the RNAi pathway. One strand of the molecule, called the "guide" strand, binds to RISC, while the other strand, known as the "passenger" strand is degraded. The guide or antisense strand of the fragment that remains bound to RISC directs the sequence-specific silencing of the target mRNA molecule. The genes can be silenced by siRNA molecules that cause the endonucleatic cleavage of the target mRNA molecules or by miRNA molecules that suppress translation of the mRNA molecule. With the cleavage or translational repression of the mRNA molecules, the genes that form them are rendered essentially inactive. RNAi is thought to have evolved as a cellular defense mechanism against invaders, such as RNA viruses, or to combat the proliferation of transposons within a cell's DNA. Both RNA viruses and transposons can exist as double-stranded RNA and lead to the activation of RNAi. Currently, siRNAs are being widely used to suppress specific gene expression and to assess the function of genes. Companies utilizing this approach include Alnylam, Sanofi, Arrowhead, Discerna, and Persomics, among others. | 1 | Gene expression + Signal Transduction |
Mediator is a crucial component for transcription initiation. Mediator interacts with the pre-initiation complex, composed of RNA Polymerase II and general transcription factors TFIIB, TFIID, TFIIE, TFIIF, and TFIIH to stabilize and initiate transcription. Studies of Mediator-RNA Pol II contacts in budding yeast have emphasized the importance of TFIIB-Mediator contacts in the formation of the complex. Interactions of Mediator with TFIID in the initiation complex has been shown.
The Structure of a core Mediator (cMed) that's associated with a core pre-initiation complex was elucidated. | 1 | Gene expression + Signal Transduction |
The use of alloys by humans started with the use of meteoric iron, a naturally occurring alloy of nickel and iron. It is the main constituent of iron meteorites. As no metallurgic processes were used to separate iron from nickel, the alloy was used as it was. Meteoric iron could be forged from a red heat to make objects such as tools, weapons, and nails. In many cultures it was shaped by cold hammering into knives and arrowheads. They were often used as anvils. Meteoric iron was very rare and valuable, and difficult for ancient people to work. | 0 | Metallurgy |
The newly formed primordial germ cells (PGC) in the implanted embryo devolve from the somatic cells at about day 7 of embryogenesis in the mouse. At this point the PGCs have high levels of methylation. These cells migrate from the epiblast toward the gonadal ridge. As reviewed by Messerschmidt et al., the majority of PGCs are arrested in the G phase of the cell cycle while they migrate toward the hindgut during embryo days 7.5 to 8.5. Then demethylation of the PGCs takes place in two waves. There is both passive and active, TET-dependent demethylation of the primordial germ cells. At day 9.5 the primordial germ cells begin to rapidly replicate going from about 200 PGCs at embryo day 9.5 to about 10,000 PGCs at day 12.5. During days 9.5 to 12.5 DNMT3a and DNMT3b are repressed and DNMT1 is present in the nucleus at a high level. But DNMT1 is unable to methylate cytosines during days 9.5 to 12.5 because the UHRF1 gene (also known as NP95) is repressed and UHRF1 is an essential protein needed to recruit DNMT1 to replication foci where maintenance DNA methylation takes place. This is a passive, dilution form of demethylation.
In addition, from embryo day 9.5 to 13.5 there is an active form of demethylation. As indicated in the Figure of the demethylation pathway above, two enzymes are central to active demethylation. These are a ten-eleven translocation (TET) methylcytosine dioxygenase and thymine-DNA glycosylase (TDG). One particular TET enzyme, TET1, and TDG are present at high levels from embryo day 9.5 to 13.5, and are employed in active TET-dependent demethylation during gametogenesis. PGC genomes display the lowest levels of DNA methylation of any cells in the entire life cycle of the mouse by embryonic day 13.5. | 1 | Gene expression + Signal Transduction |
In a cell, there are several non-canonical bases present: CpG islands in DNA (often methylated), all eukaryotic mRNA (capped with a methyl-7-guanosine), and several bases of rRNAs (methylated). Often, tRNAs are heavily modified postranscriptionally in order to improve their conformation or base pairing, in particular in or near the anticodon: inosine can base pair with C, U, and even with A, whereas thiouridine (with A) is more specific than uracil (with a purine). Other common tRNA base modifications are pseudouridine (which gives its name to the TΨC loop), dihydrouridine (which does not stack as it is not aromatic), queuosine, wyosine, and so forth. Nevertheless, these are all modifications to normal bases and are not placed by a polymerase. | 1 | Gene expression + Signal Transduction |
* Interdisciplinary field involving processes that
** make use of microbes, usually bacteria and archaea
** mainly take place in aqueous environment
** deal with metal production and treatment of metal containing materials and solutions
*"Biohydrometallurgy may generally referred to as the branch of biotechnology dealing with the study and application of the economic potential of the interactions between microbes and minerals. It concerns, thus, all those engaged, directly or indirectly, in the exploitation of mineral resources and in environmental protection: geologists, economic geologists, mining engineers, metallurgists, hydrometallurgists, chemists and chemical engineers. In addition to these specialists, there are the microbiologists whose work is indispensable in the design, implementation and running of biohydrometallurgical processes."
*Biohydrometallurgy was first used more than 300 years ago to recover copper. The uses have evolved to extracting gold, uranium, and other metals. | 0 | Metallurgy |
Due to the range of genes that Pol II transcribes, this is the polymerase that experiences the most regulation by a range of factors at each stage of transcription. It is also one of the most complex in terms of polymerase cofactors involved.
Initiation is regulated by many mechanisms. These can be separated into two main categories:
#Protein interference.
#Regulation by phosphorylation. | 1 | Gene expression + Signal Transduction |
GTPases are a large family of hydrolase enzymes that bind to the nucleotide guanosine triphosphate (GTP) and hydrolyze it to guanosine diphosphate (GDP). The GTP binding and hydrolysis takes place in the highly conserved P-loop "G domain", a protein domain common to many GTPases. | 1 | Gene expression + Signal Transduction |
Endoglin has been shown to interact with high affinity to TGF beta receptor 3 and TGF beta receptor 1, and with lower affinity to TGF beta receptor 2. It has high sequence similarity to another TGF beta binding protein, betaglycan, which was one of the first cues that indicated that endoglin is a TGF beta binding proteins. However, it has been shown that TGF beta binds with high affinity to only a small amount of the available endoglin, which suggests that there is another factor regulating this binding.
Endoglin itself doesnt bind the TGF beta ligands, but is present with the TGF beta receptors when the ligand is bound, indicating an important role for endoglin. The full length endoglin will bind to the TGF beta receptor complex whether TGF beta is bound or not, but the truncated forms of endoglin have more specific binding. The amino acid (aa) region 437–558 in the extracellular domain of endoglin will bind to TGF beta receptor II. TGF beta receptor I binds to the 437-588 aa region and to the aa region between 437 and the N-terminus. Unlike TGF beta receptor I which can only bind the cytoplasmic tail when its kinase domain is inactive, TGF beta receptor II can bind endoglin with an inactive and active kinase domain. The kinase is active when it is phosphorylated. Furthermore, TGF beta receptor I will dissociate from endoglin soon after it phosphorylates its cytoplasmic tail, leaving TGF beta receptor I inactive. Endoglin is constituitively phosphorylated at the serine and threonine residues in the cytoplasmic domain. The high interaction between endoglins cytoplasmic and extracellular tail with the TGF beta receptor complexes indicates an important role for endoglin in the modulation of the TGF beta responses, such as cellular localization and cellular migration.
Endoglin can also mediate F-actin dynamics, focal adhesions, microtubular structures, endocytic vesicular transport through its interaction with zyxin, ZRP-1, beta-arrestin and Tctex2beta, LK1, ALK5, TGF beta receptor II, and GIPC. In one study with mouse fibroblasts, the overexpression of endoglin resulted in a reduction of some ECM components, decreased cellular migration, a change in cellular morphology and intercellular cluster formation. | 1 | Gene expression + Signal Transduction |
Naturally occurring bases can be divided into two classes according to their structure:
* Pyrimidines are six-membered heterocyclic with nitrogen atoms in position 1 and 3.
* Purines are bicyclic, consisting of a pyrimidine fused to an imidazole ring.
Artificial nucleotides (Unnatural Base Pairs (UBPs) named d5SICS UBP and dNaM UBP) have been inserted into bacterial DNA but these genes did not template mRNA or induce protein synthesis. The artificial nucleotides featured two fused aromatic rings which formed a (d5SICS–dNaM) complex mimicking the natural (dG–dC) base pair. | 1 | Gene expression + Signal Transduction |
The Falcon Concentrator is a type of gravity separation device for the recovery of valuable metals and minerals. There are three types of Falcon Concentrators: Falcon Semi-Batch (SB), Falcon Continuous (C) and Falcon Ultra-Fine (UF). All models of Falcon Concentrator rely on the creation of centrifugal forces by way of a rapidly rotating, vertical bowl in order to stratify and separate particles based on weight. The amount of gravitational force generated and the method of collecting these heavier particles differs for each model. | 0 | Metallurgy |
PELP1 is located on chromosome 17p13.2 and PELP1 is expressed in a wide variety of tissues; its highest expression levels are found in the brain, testes, ovaries, and uterus. Currently, there are two known isoforms (long 3.8 Kb and short 3.4 Kb) and short isoform is widely expressed in cancer cells. | 1 | Gene expression + Signal Transduction |
Bacterial initiation factor 1 is a bacterial initiation factor.
IF1 associates with the 30S ribosomal subunit in the A site and prevents an aminoacyl-tRNA from entering. It modulates IF2 binding to the ribosome by increasing its affinity. It may also prevent the 50S subunit from binding, stopping the formation of the 70S subunit. It also contains a β-domain fold common for nucleic acid binding proteins.
IF1–IF3 may also perform ribosome recycling. | 1 | Gene expression + Signal Transduction |
Also during Phase II, copper and arsenical bronze production was practiced at the site.
Norşuntepe provides first clear and unambiguous evidence of arsenical bronze production in this general area before the 4th millennium. It demonstrates that some form of arsenic alloying was being deliberately practised. Since the slag identified at Norşuntepe contains no arsenic, this means that arsenic-bearing materials were added separately. The evidence was discovered at the levels with Ubaid style ceramics, where also were found a number of structures related to the Mesopotamian architectural traditions. A related site in the area from the same time period is Değirmentepe, where arsenic-bronze was also produced around 4200 BC.
The final Chalcolithic phases were characterized by small-scale single-room houses. Radiocarbon dating from the different Chalcolithic levels provided dates between 4300-3800 BC. | 0 | Metallurgy |
RNA polymerase II holoenzyme stability determines the number of base pairs that can be transcribed before the holoenzyme loses its ability to transcribe. The length of the CTD is essential for RNA polymerase II stability. RNA polymerase II stability has been shown to be regulated by post-translation proline hydroxylation. The von Hippel–Lindau tumor suppressor protein (pVHL, human GeneID: 7428) complex binds the hyperphosphorylated large subunit of the RNA polymerase II complex, in a proline hydroxylation- and CTD phosphorylation-dependent manner, targeting it for ubiquitination. | 1 | Gene expression + Signal Transduction |
The upcasting (up-casting, upstream, or upward casting) is a method of either vertical or horizontal continuous casting of rods and pipes of various profiles (cylindrical, square, hexagonal, slabs etc.) of 8-30mm in diameter. Copper (Cu), bronze (Cu·Sn alloy), nickel alloys are usually used because of greater casting speed (in case of vertical upcasting) and because of better physical features obtained. The advantage of this method is that metals are almost oxygen-free and that the rate of product crystallization (solidification) may be adjusted in a crystallizer - a high-temperature resistant device that cools a growing metal rod or pipe by using water.
The method is comparable to Czochralski method of growing silicon (Si) crystals, which is a metalloid. | 0 | Metallurgy |
The term "autoinduction" was first coined in 1970, when it was observed that the bioluminescent marine bacterium Vibrio fischeri produced a luminescent enzyme (luciferase) only when cultures had reached a threshold population density. At low cell concentrations, V. fischeri did not express the luciferase gene. However, once the cultures had reached exponential growth phase, the luciferase gene was rapidly activated. This phenomenon was termed “autoinduction” because it involved a molecule (autoinducer) that accumulated in a growth medium and induced the synthesis of components of the luminescence system. Subsequent research revealed that the actual autoinducer used by V. fischeri is an acylated homoserine lactone (AHL) signaling molecule. | 1 | Gene expression + Signal Transduction |
The location of the ropB gene is directly and sequentially proximal to the subject of its transcriptional regulation (speB) which lies downstream of a 941 bp intergenic region between the two. Transcription of the ropB gene seems to necessitate a promoter within a series sequences between 238 and 480 bp and up to 800 bp upstream of the gene itself inside the highly repetitive intergenic region. | 1 | Gene expression + Signal Transduction |
Structures of eIF4F components have been solved individually and as partial complexes by a variety of methods, but no complete structure of eIF4F is currently available. | 1 | Gene expression + Signal Transduction |
Evidence that eRNAs cause downstream effects on the efficiency of enhancer activation and gene transcription suggests its functional capabilities and potential importance.
The transcription factor p53 has been demonstrated to bind enhancer regions and generate eRNAs in a p53-dependent manner. In cancer, p53 plays a central role in tumor suppression as mutations of the gene are shown to appear in 50% of tumors. These p53-bound enhancer regions (p53BERs) are shown to interact with multiple local and distal gene targets involved in cell proliferation and survival. Furthermore, eRNAs generated by the activation of p53BERs are shown to be required for efficient transcription of the p53 target genes, indicating the likely important regulatory role of eRNAs in tumor suppression and cancer. Generally, mutations in eRNA have been shown to demonstrate similar phenotypic behavior in oncogenesis as compared to protein-coding RNA.
Variations in enhancers have been implicated in human disease but a therapeutic approach to manipulate enhancer activity is currently not possible. With the emergence of eRNAs as important components in enhancer activity, powerful therapeutic tools such as RNAi may provide promising routes to target disruption of gene expression. | 1 | Gene expression + Signal Transduction |
A neolithic-chalcolithic tell is located south of the town.
The first occupation phase at Aratashen was pre-ceramic, going back to 6500 BCE. Parallels are found in the southeastern Trans-Caucasia, and in the northeastern Mesopotamia, especially based on the construction techniques and the lithic and bone tools.
Also the pottery, after it appears, is somewhat similar. The best parallels are with Kul Tepe of Nakhichevan to the south, and with the northern Near East, such as the lower levels of Hajji Firuz Tepe, at Dalma Tepe, and at Tilki Tepe.
The Shulaveri-Shomutepe culture, that developed in the neighbouring Kura basin and the Karabakh steppe, does not have close parallels with the early Aratashen artifacts.
At Aratashen, obsidian was discovered that came from Turkish sources at Meydan Dağ, in the Lake Van basin; these samples were found in association with the very early Halaf culture ware, which probably also came to Aratashen from the same area.
Other types of pottery appear at the end of the fifth millennium BC. At this time, the plain of Ararat was in contact with the contemporary populations of northern Mesopotamia, and also with those of the ‘Sioni culture’ of the Kura basin.
The pottery of the second occupation phase of Aratashen is becoming close to that in the Ararat plain. Here we see the influence of the Late Chalcolithic horizon of approximately 4300–3500 BC in the whole of northern Mesopotamia, such as:
: "... development of straw-tempered ware, initial use of the slow wheel, early forms of standardization in manufacture and typological features ("Coba bowls"), a frequent surface treatment with light scraping..."
This pottery has many Transcaucasian, or Sioni culture features. Sioni culture generally succeeded the
Shulaveri-Shomutepe culture in some areas. Here we already see the features of the later Kura–Araxes culture pottery. | 0 | Metallurgy |
Hammond died on January 6, 1908, aged 74. He is interred in Mount Auburn Cemetery, Cambridge, Massachusetts. | 0 | Metallurgy |
There is great variability in the use of the lost-wax method in East Asia. The casting method to make bronzes till the early phase of Eastern Zhou (770-256 ) was almost invariably section-mold process. Starting from around 600 , there was an unmistakable rise of lost-wax casting in the central plains of China, first witnessed in the Chu cultural sphere.
Further investigations have revealed this not to be the case as it is clear that the piece-mould casting method was the principal technique used to manufacture bronze vessels in China. The lost-wax technique did not appear in northern China until the 6th century BC. Lost-wax casting is known as rōgata in Japanese, and dates back to the Yayoi period, . The most famous piece made by cire perdue is the bronze image of Buddha in the temple of the Todaiji monastery at Nara. It was made in sections between 743 and 749, allegedly using seven tons of wax. | 0 | Metallurgy |
Pro-inflammatory cytokine IL-12 is produced in heterodimer form by B cells and antigen-presenting cells. Binding of IL-12 to IL-12R, which is composed of two different subunits (IL12Rβ1 and IL12Rβ2), leads to the interaction of IL12Rβ1 and IL12Rβ2 with JAK2 and TYK2, which is followed by phosphorylation of STAT4 tyrosine 693. The pathway then induces IFNγ production and Th1 differentiation. STAT4 is critical in promotion of antiviral response of natural killer (NK) cell by targeting of promotor regions of Runx1 and Runx3. | 1 | Gene expression + Signal Transduction |
Aluminium and its alloys are difficult to solder due to the formation of the passivation layer of aluminium oxide. The flux has to be able to disrupt this layer and facilitate wetting by solder. Salts or organic complexes of some metals can be used; the salt has to be able to penetrate the cracks in the oxide layer. The metal ions, more noble than aluminium, then undergo a redox reaction, dissolve the surface layer of aluminium and form a deposit there. This intermediate layer of another metal then can be wetted with a solder.
One example of such flux is a composition of triethanolamine, fluoroboric acid, and cadmium fluoroborate. More than 1% magnesium in the alloy impairs the flux action, however, as the magnesium oxide layer is more refractory. Another possibility is an inorganic flux composed of zinc chloride or tin(II) chloride, ammonium chloride, and a fluoride (e.g. sodium fluoride). Presence of silicon in the alloy impairs the flux effectivity, as silicon does not undergo the exchange reaction aluminium does. | 0 | Metallurgy |
Role of mitogen signaling in cell cycle progression
The ERK pathway plays an important role of integrating external signals from the presence of mitogens such as epidermal growth factor (EGF) into signaling events promoting cell growth and proliferation in many mammalian cell types. In a simplified model, the presence of mitogens and growth factors trigger the activation of canonical receptor tyrosine kinases such as EGFR leading to their dimerization and subsequent activation of the small GTPase Ras. This then leads to a series of phosphorylation events downstream in the MAPK cascade (Raf-MEK-ERK) ultimately resulting in the phosphorylation and activation of ERK. The phosphorylation of ERK results in an activation of its kinase activity and leads to phosphorylation of its many downstream targets involved in regulation of cell proliferation. In most cells, some form of sustained ERK activity is required for cells to activate genes that induce cell cycle entry and suppress negative regulators of the cell cycle. Two such important targets include Cyclin D complexes with Cdk4 and Cdk6 (Cdk4/6) which are both phosphorylated by ERK. The transition from G1 to S phase is coordinated by the activity of Cyclin D-Cdk4/6, which increases during late G1 phase as cells prepare to enter S-phase in response to mitogens. Cdk4/6 activation contributes to hyper-phosphorylation and the subsequent destabilization of retinoblastoma protein (Rb). Hypo-phosphorylated Rb, is normally bound to transcription factor E2F in early G1 and inhibits its transcriptional activity, preventing expression of S-phase entry genes including Cyclin E, Cyclin A2 and Emi1. ERK1/2 activation downstream of mitogen induced Ras signaling is necessary and sufficient to remove this cell cycle block and allow cells to progress to S-phase in most mammalian cells.
Downstream feedback control and generation of a bistable G1/S switch
The restriction point (R-point) marks the critical event when a mammalian cell commits to proliferation and becomes independent of growth stimulation. It is fundamental for normal differentiation and tissue homeostasis, and seems to be dysregulated in virtually all cancers. Although the R-point has been linked to various activities involved in the regulation of G1–S transition of the mammalian cell cycle, the underlying mechanism remains unclear. Using single-cell measurements, Yao et al., shows that the Rb–E2F pathway functions as a bistable switch to convert graded serum inputs into all-or-none E2F responses.
Growth and mitogen signals are transmitted downstream of the ERK pathway are incorporated into multiple positive feedback loops to generate a bistable switch at the level of E2F activation. This occurs due to three main interactions during late G1 phase. The first is a result of mitogen stimulation though the ERK leading to the expression of the transcription factor Myc, which is a direct activator of E2F. The second pathway is a result of ERK activation leading to the accumulation of active complexes of Cyclin D and Cdk4/6 which destabilize Rb via phosphorylation and further serve to activate E2F and promote expression of its targets. Finally, these interactions are all reinforced by an additional positive feedback loop by E2F on itself, as its own expression leads to production of the active complex of Cyclin E and CDK2, which further serves to lock in a cell's decision to enter S-phase. As a result, when serum concentration is increased in a gradual manner, most mammalian cells respond in a switch-like manner in entering S-phase. This mitogen stimulated, bistable E2F switch is exhibits hysteresis, as cells are inhibited from returning to G1 even after mitogen withdrawal post E2F activation.
'Dynamic signal processing by the ERK pathway
'<br>
The EGFR-ERK/MAPK (epidermal growth factor receptor extracellular-regulated kinase/mitogen-activated protein kinase) pathway stimulated by EGF is critical for cellular proliferation, but the temporal separation between signal and response obscures the signal-response relationship in previous research.In 2013, Albeck et al. provided key experimental evidence to fill this gap of knowledge. They measured signal strength and dynamics with steady-state EGF stimulation, in which the signaling and output can be easily related. They further mapped the signal-response relationship across the pathway’s full dynamic range. Using high-content immunofluorescence (HCIF) detection of phosphorylated ERK (pERK) and live cell FRET biosensors, they monitored downstream output of the ERK pathway in both live cells and fixed cells. To further link the quantitative characteristics of ERK signaling to proliferation rates, they established a series of steady-state conditions using a range of EGF concentrations by applying EGF with different concentrations.
Single cell imaging experiments have shown ERK to be activated in stochastic bursts in the presence of EGF. Furthermore, the pathway has been shown to encode the strength of signaling inputs though frequency modulated pulses of its activity. Using live cell FRET biosensors, cells induced with different concentrations of EGF illicit activity bursts of different frequency, where higher levels of EGF resulted in more frequent bursts of ERK activity. To figure out how S phase entry can be affected by sporadic pulses of ERK activity at low EGF concentrations, they used MCF-10A cells co-expressing EKAR-EV and RFP-geminin and identified the pulses of ERK activity with the scoring and then align this ERK activity profiles with time of GFP-geminin induction. They found that longer periods of ERK activity stimulate S phase entry, as suggested by increased pulse length. To understand the dynamics of EGFR-ERK pathway, specifically how is the frequency and amplitude modulated, they applied the EGFR inhibitor gefitinib or the highly selective MAPK/ERK kinase (MEK) inhibitor PD0325901 (PD). Two inhibitors yield actually a little bit different result: gefitinib, at intermediate concentration, would induce pulsatory behavior and also bimodal shift, which is not observed with PD. They further combine EGF and PD together and draw the conclusion that the frequency of ERK activities is modulated by quantitative variation while the amplitude is modulated by MEK activity’s change. Lastly they turned to Fra-1, one of downstream effectors of ERK pathway, as it’s technically challenging to estimate ERK activities directly. To understand how the integrated ERK pathway output (which should be independent of either frequency or amplitude) affect the proliferation rate, they used the combination of a wide range of EGF and PD concentrations and find that there’s actually an inverted “L” shape single curvilinear relationship, which suggests that at low levels of ERK pathway output, small changes in signal intensity correspond to large changes in proliferative rate, while large changes in signal intensity near the high end of the dynamic range have little impact on proliferation. The fluctuation of ERK signaling highlights potential issues with current therapeutic approaches, providing new perspective in terms of thinking about drug targeting in the ERK pathway in cancer.
Integration of mitogen and stress signals in proliferation
Recent live cell imaging experiments in MCF10A and MCF7 cells have shown that a combination of mitogen signaling though ERK and stress signals through activation of p53 in mother cells contributes to the likelihood of whether newly formed daughter cells will immediately re-enter the cell cycle or enter quiescence (G0) preceding mitosis. Rather than daughter cells starting with no key signaling proteins after division, mitogen/ERK induced Cyclin D1 mRNA and DNA damage induced p53 protein, both long lived factors in cells, can be stably inherited from mother cells after cell division. The levels of these regulators vary from cell to cell after mitosis and stoichiometry between them strongly influences cell cycle commitment though activation of Cdk2. Chemical perturbations using inhibitors of ERK signaling or inducers p53 signaling in mother cells suggest daughter cells with high levels of p53 protein and low levels of Cyclin D1 transcripts were shown to primarily enter G0 whereas cells with high Cyclin D1 and low levels of p53 are most likely to reenter the cell cycle. These results illustrate a form of encoded molecular memory though the history of mitogen signaling through ERK and stress response though p53. | 1 | Gene expression + Signal Transduction |
In addition to its role in synaptic plasticity described above, PI3K-AKT signaling pathway also has an important role in brain growth, which is altered when PI3K signaling is disturbed. For example, intracranial volume is also associated with this pathway, in particular with AKT3 intronic variants. Thyroid hormone was originally identified as the primary regulator of brain growth and cognition, and recent evidence has demonstrated that thyroid hormone produces some of its effects on the maturation and plasticity of synapses through PI3K. | 1 | Gene expression + Signal Transduction |
In parallel with this work, the Cell was tested for the recovery of fine coal at the Newlands coal mine, also owned by MIM Holdings Limited. This fines stream was cyclone overflow, which contained 15–50% ash and was previously discarded. The particle size of this stream was less than 25 μm. Pilot plant testing showed that it was possible to achieve greater than 90% recovery of coal, with less than 10% ash in the product.
Subsequently, a full-scale plant was commissioned at Newlands in the 1988–89 financial year, with six rectangular Cells (1.5 m × 3.5 m) installed in a two-stage arrangement. The cells in the first stage had seven downcomers, while those in the second had six.
These cells were in continuous operation at Newlands for 15 years until a new washing plant was built to replace the old one in 2006.
Two additional Cells were installed at MIM Holdings' Collinsville Coal operations in 1990. These had 10 downcomers each. | 0 | Metallurgy |
During the next thousand years of the Early Bronze Age (end of 4th–end of 3rd millennium BCE) the same unalloyed copper production of the Chalcolithic (group 2, above) continued for the production of short blades and points. The same metal technique was used for the novel production of long blade weapons
(riveted daggers and knives, heavy tanged swords, and epsilon-shaped axes). The same copper production
technique of casting into an open mould and then hammering and annealing, was used to produce all other
metals as well, including jewelry of thin plates, sometimes decorated, and elongated thin wires (mainly for rings and bracelets) made of unalloyed copper as well as from silver (first appearance) and gold.
Archaeological remains of Early Bronze copper mining and copper smelting in the vicinity of the
mines were found in Trans-Jordan (Feinan), the Arava Valley (Timnah), and southern Sinai. The only production remains of metal are those of copper and include copper slag, prills, and amorphous copper lumps and small shallow ball-shaped clay crucibles with a socket. In the Early Bronze I site of the Ashkelon Marina, in the southern part of the Israeli coast, small shallow open pits, probably for the melting of copper in a crucible, were found next to copper industrial remains.
All pits showed a similar structure of a red soil burnt layer covered within by a white thin layer of calcite. No archaeological material was found associated with these man-made rudimentary remains. In the vicinity, and detached from the installations, scattered remains of pottery sherds, bone fragments, copper slag remains, and some pieces of clay crucibles were found. They were dated to Early Bronze Age I. Optically stimulated luminescence (OSL) ages of the fill of the pits and thermoluminescence (TL) ages of quartz grains extracted from the hardened red layer of the pits showed that the last burning activity was conducted during the same period: 5260 ± 380 years ago (OSL) and 5180 ± 380 years ago (TL).
Most of the metal products are found in burials, and are mainly from the Early Bronze I. The same types of metals continue in sites and tombs throughout the entire Early Bronze and all over the local distribution map of Early Bronze sites in Israel, from the Upper Galilee in the north to Ein Besor and Malhata in the northern Negev. A single hoard of copper objects probably from the Early Bronze I was found with no related archaeological context in the
fields of Kfar Monash.
During the Early Bronze period the Southern Levants metal industry became more specialized and organized in separated places for the different parts of production, and the products became more homogenous, as did the different materials and modes of production. For the first time in the Southern Levants metal history, significant typological and technological affiliations to the growing metal industries in the two major imperial centers (Egypt and Mesopotamia) on both sides of the “Fertile Crescent” were visible. During all the Early Bronze Age there is no archaeometallurgical evidence for bronze production and no bronze objects were found during this period in the Southern Levant as opposed to unalloyed copper. | 0 | Metallurgy |
The chromosome loops shown in the figure, bringing an enhancer to the promoter of its target gene, may be directed and formed by the eRNA transcribed from the enhancer after the enhancer is activated.
A transcribed enhancer RNA (eRNA) interacting with the complex of Mediator proteins (see Figure), especially Mediator subunit 12 (MED12), appears to be essential in forming the chromosome loop that brings the enhancer into close association with the promoter of the target gene of the enhancer in the case of five genes studied by Lai et al. Hou and Kraus, describe two other studies reporting similar results. Arnold et al. review another 5 instances where eRNA is active in forming the enhancer-promoter loop. | 1 | Gene expression + Signal Transduction |
The PI3K pathway is a major source of drug resistance in prostate cancer. This is particularly true in castration-resistant prostate cancer, where tumours become resistant to androgen-deprivation therapy, which block the tumours ability to utilise the hormone androgen to grow. This is due to a complex feedback mechanism which exists between the androgen receptor and the PI3K pathway. As in other tumour types, mutations in key genes of this pathway can lead to hyperactivation of this pathway, for example in PIK3CA, Increases in the copy number of PIK3CA and increased mRNA expression also increases pathway activation in prostate cancers among others. Gains in the nearby genetic region 3q26.31-32 have been shown to co-occur with a number of nearby PI3K family members including PIK3CA, PIK3CB and PIK3R4, leading to transcriptional changes in PIK3C2G, PIK3CA, PIK3CB, PIK3R4 as well as pathways associated with cell proliferation. These large spanning gains associate with Gleason grade, tumour stage, lymph node metastasis and other aggressive clinical features. In patients treated with PI3K inhibitors, those with copy number gains in PIK3CB appear to have increased drug susceptibility. | 1 | Gene expression + Signal Transduction |
Eco pickled surface technology has been tested and approved for use as a replacement for acid pickled steel by automotive manufacturers General Motors and Chrysler. The Eco Pickled Surface process was a finalist in the 2013 American Metal Market (AMM) Awards for Steel Excellence. | 0 | Metallurgy |
While rich veins of tin are known to exist in Central and South Africa, whether these were exploited during ancient times is still debated . However, the Bantu culture of Zimbabwe are known to have actively mined, smelted and traded tin between the 11th and 15th centuries AD. | 0 | Metallurgy |
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