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KKR 25 is a galaxy 6.1 million light years (1.90 million parsecs) away from the Earth. is located outside the Local Group but the Local group is the nearest galaxy group with the M81 Group being the second nearest. | https://en.wikipedia.org/wiki?curid=48848288 |
NGC 6215 (also known as "PGC 59112") is a spiral galaxy located in the constellation Ara. It is designated as SA(s)c in the galaxy morphological classification scheme. It was discovered by astronomer John Herschel on 9 July 1836.<ref name="The NGC/IC Project"></ref> is part of galaxy group NGC 6221/15, which includes barred spiral galaxy NGC 6221 and three dwarf galaxies. A bridge of neutral hydrogen gas connects and 6221 as a result of their interaction, and Dwarf 3 of the three dwarf galaxies may have formed from the bridging gas. | https://en.wikipedia.org/wiki?curid=48848546 |
George H. Denton (born 14 December 1939 in Orono, Maine, USA) is a Professor of Geological Sciences and Quaternary Studies at the University of Maine. Denton earned his Ph.D. at the Yale University in 1965, and was the first scientist from the University of Maine elected to the National Academy of Sciences. His primary interest is the geological history of large ice sheets and smaller mountain glaciers, and in particular the role of these ice sheets in Quaternary and late-Tertiary ice ages. He also focuses on the abrupt ocean-atmosphere reorganizations in glacial cycles. One current project (2015) deals with the Quaternary and late Tertiary history of the Antarctic Ice Sheet. Studies of late Quaternary glacial deposits elucidate the role of the Antarctic Ice Sheet during the last few ice ages. Studies of late Tertiary deposits bear on fundamental climatic changes that preceded Quaternary ice ages. Recent projects involved reconstruction of Northern Hemisphere ice sheets during the last ice age. Another project deals with the alpine glacier history of the Chilean Andes. He led a party of scientists doing field studies in Chile in 1991–99, and in New Zealand in 2000–08 together with his close colleague throughout his career, the late Norwegian Quaternary geologist Professor Bjørn G. Andersen of the University of Oslo. Denton has been widely acclaimed for his research in glacial geology and the Denton Glacier and the Denton Hills in Antarctica were named in his honor | https://en.wikipedia.org/wiki?curid=48867329 |
George H. Denton In 1990, he received the prestigious Vega Medal (Gold) from the Swedish Society for Anthropology and Geography and in 1996 he was elected to the Royal Swedish Academy of Sciences. Denton's research has inspired several generations of students, many of whom have picked up researching in Earth Science. | https://en.wikipedia.org/wiki?curid=48867329 |
Victoria Lieu K.O. was a Chinese entomologist known for her studies of "Aegeriidae" (mulberry borers) and "Cerambycidae" (citrus borers). | https://en.wikipedia.org/wiki?curid=48871130 |
The Star of Bethlehem (2007 film) The Star of Bethlehem is a 2007 documentary by Frederick A. "Rick" Larson to show what he found when he searched for clues about the Star of Bethlehem. Larson used the Starry Night astronomy computer program along with an article written by astronomer Craig Chester; based in part on the work of Ernest Martin. Larson also used details from the Christian Bible to find nine data points about the Star of Bethlehem which, according to the second chapter of the Gospel of Matthew, stopped over Bethlehem, bringing the Magi to Jesus. Larson's interest in the Star of Bethlehem began when he needed to make a Christmas Star to accompany his Magi lawn ornaments he had made to be Christmas decorations, but did not know what the Star of Bethlehem was and needed to learn more. As a lawyer, Larson examined the text of Matthew, finding nine pieces of evidence in the nativity passage. The Star’s nine data points are that it signified birth, it signified kingship, it was related to the Jewish nation, and it "rose in the East"; it was not known to Herod the Great; it appeared at a specific time; it endured over time; it was before the Magi as they traveled south to Bethlehem from Jerusalem, and then, according to the Bible, it stopped over the city of Bethlehem. Using astronomy software to return to the skies over Judea by using Johannes Kepler's math to calculate positions of celestial objects, Larson thinks he found all nine elements found in the book of "Matthew" | https://en.wikipedia.org/wiki?curid=48896127 |
The Star of Bethlehem (2007 film) He also believes that the Star of Bethlehem, is Jupiter, a wandering star, and it stopped over Bethlehem during its retrograde motion on December 25, 2 BC. Larson believes King Herod the Great died in 1 BC, although almost all other experts, including astronomer David Hughes and astronomer Michael Molnar, believe Herod died in 4 BC. (In Molnar's book, "The Star of Bethlehem: The Legacy of the Magi", he documents Jesus' birth as Saturday [Sabbath] April 17, 6 BC due to a triple conjunction in Aries.) Once Larson found what he thinks is the time of Jesus Christ's birth, he looked for signs appearing in the heavens at possible times that fit the Passover, and believes the date of the Christ's (Messiah's) crucifixion was April 3, 33 AD on the Gregorian calendar. He also thinks he found astronomical phenomena related to a vision in the Book of Revelation. Frederick Larson wrote the screenplay to "The Star of Bethlehem" and was co-executive producer along with Stephen McEveety. McEveety co-produced The Passion of the Christ, which won 22 awards including the People's Choice Award, the ASCAP Top Box Office Films Award, and an Academy Award for best cinematography. McEveety also co-produced Braveheart, which won 30 awards, including five Academy Awards, and whose films also include "The Man Without a Face", "Immortal Beloved", "We Were Soldiers", and "Payback". Stephen Vidano directed this film and Julie Davison Larson composed its music. Larson released this documentary in 2007 (63 minutes) and in 2009 (65 minutes) | https://en.wikipedia.org/wiki?curid=48896127 |
The Star of Bethlehem (2007 film) It received five Doves from the Dove Foundation, which considered the film acceptable for all ages. Christian Cinema reviewer Angela Walker wrote, "The Star of Bethlehem doesn't have an MPAA rating, but the nature of the subject would probably earn it a PG for thematic elements (that being the birth of Jesus Christ)." "Starry Night Companion : Your guide to understanding the night sky using Starry Night" by John Mosley. 2004. | https://en.wikipedia.org/wiki?curid=48896127 |
Karl Friedrich Ermisch (13 July 1898 – 22 July 1970) was a German teacher and entomologist. Ermisch was born in Dresden, Germany. His studies to become a teacher were interrupted by World War I, but in 1921, he became a teacher in Sohl. He spent 1933 to 1945 in Dusseldorf, returning to Sohl in 1945 to resume his teaching career, eventually becoming head teacher. He later went on to become Professor of Biology at two teacher training colleges. In 1954, he joined the College of Physical Culture in Leipzig. He finally retired in 1963, dying in 1970 in Leipzig. In 1921, Ermisch received a small collection of beetles, which he soon began to expand. This work was to continue until his death, including collecting trips to the Caucasus and Bulgaria. Unfortunately, during a move, some 73 of the 200 boxes containing his collection were destroyed, including all of the Mordellidae that he had described up to that time. | https://en.wikipedia.org/wiki?curid=48918607 |
The Natural History of Aleppo is a 1756 book by naturalist Alexander Russell on the natural history of Aleppo. In 1794 his half-brother, Patrick Russell, revised and expanded the text in a second edition. The book is significant for its quality, the contemporary interest it attracted, and for being a product of the Scottish Enlightenment. When the book was published it was immediately an important European record and perspective on the state of contemporary science in Syria. The book contains the earliest known description of the Syrian hamster. | https://en.wikipedia.org/wiki?curid=48922850 |
Pablo Groeber (born Paul Friedrich Karl Gröber; 1885–1964) was a German geologist known for his contributions to the understanding of the geology of Tien Shan in Central Asia and the Andes of Nequén and Mendoza Province in Argentina. | https://en.wikipedia.org/wiki?curid=48943485 |
Barcelona astrolabe The astrolabe of Barcelona is considered the most ancient astrolabe with Carolingian characters that has survived in the Christian Occident. The French researcher Marcel Destombes founded the astrolabe, and left it as legacy to the Institute of the Arab World of Paris in 1983. The Academy of Sciences of Barcelona asked the astrolabe in loan to the Musée of l'Institut du Monde Arabe, to make a replica, today this replica is on display at the Academy of Sciences in the Ramblas. This astrolabe presents some unusual characteristics. All the engraved characters are in Latin, this fact made the scholars think that the instrument was made in the Christian Europe. The pointers of his "spider" indicate eighteen stars: ten boreal stars and eight austral stars (that is to say, situated beneath of the equator). Eleven of them correspond to the date of 980 AD. Still like this, the names of the stars are not engraved on the brass. The words ROME and FRANCE are engraved in Latin characters in one of the eardrums. These characters are accompanied by the numbers 41-30 (in Arabic figures). The characters are identical to those used at the end of the 10th century in the Catalan Latin manuscripts, being Catalonia in that moment a mark of the Carolingian France. This would explain the presence of the word FRANCE. The figures express in degrees and minutes: 41° 30′, which correspond exactly to the latitude of Barcelona. The fact of having engraved the date 980 AD | https://en.wikipedia.org/wiki?curid=48944856 |
Barcelona astrolabe and the latitude of Barcelona (41–30), which archdeacon in those dates was Sunifred Llobet, to whom is attributed the authorship of the Ripoll's manuscript: ms.225, which contains the description of an astrolabe, has led the scholars to attribute the paternity of the astrolabe to this famous astronomer, also known with the name of Lupitus Barchinonensis | https://en.wikipedia.org/wiki?curid=48944856 |
NGC 524 is a lenticular galaxy in the constellation Pisces. It is at a distance of about 90 million light-years away from Earth. In the central bulge of the galaxy is visible gas forming a spiral structure. It is the largest galaxy in a small galaxy group, the group, which is associated with NGC 488 and its group. It was discovered by William Herschel in 1786. Two supernovae have been observed in the galaxy, SN 2000cx, a type Ia-p peaking at 14.5 magnitude, and SN 2008Q, type Ia. | https://en.wikipedia.org/wiki?curid=48946287 |
Wawrzyniec Teisseyre Wawrzyniec Karol de Teisseyre (1860–1939) was a Polish geologist who is known for his work on the southern part of the Trans European Suture Zone and Galician and Romanian geology. was born in Cracow (Poland) of French ancestry. He studied at the University of Vienna and the Mining Academy in Leoben (Austria) and worked at the institutes of geology in Vienna and Bucharest. As part of his work on the Geological Atlas of Galicia, he mapped the southern part of the Trans European Suture Zone (Teisseyre-Tornquist Zone) and associated features of the Carpathian Mountains. During his time in Bucharest he investigated oil deposits of Romania. | https://en.wikipedia.org/wiki?curid=48952302 |
NGC 6394 is a barred spiral galaxy located in the constellation Draco. It is designated as SBb in the galaxy morphological classification scheme and was discovered by the American astronomer Lewis A. Swift on 7 July 1885.<ref name="NASA/IPAC"></ref> | https://en.wikipedia.org/wiki?curid=48954957 |
Plant press A plant press is a set of equipment used by botanists to flatten and dry field samples so that they can be easily stored. A professional plant press is made to the standard maximum size for biological specimens to be filed in a particular herbarium. A flower press is a similar device of no standard size that is used to make flat dried flowers for pressed flower craft. Specimens prepared in a plant press are later glued to archival-quality card stock with their labels, and are filed in a herbarium. Labels are made with archival ink (or pencil) and paper, and attached with archival-quality glue. A modern plant press consists of two strong outer boards with straps that can be tightened around them to exert pressure. Between the boards, fresh plant samples are placed, carefully labelled, between layers of paper. Further layers of absorbent paper and corrugated cardboard are usually added to help to dry the samples as quickly as possible, which prevents decay and improves colour retention. Layers of a sponge material can be used in order to prevent squashing parts of the specimens, such as fruit. Older plant presses and some modern flower presses have screws to supply the pressure, which often limits the thickness of the stack of samples that can be put into one press. Luca Ghini (1490—1556) Italian physician and botanist, created the first recorded herbarium, and is considered the first person to have used drying under pressure to prepare a plant collection | https://en.wikipedia.org/wiki?curid=48955231 |
Plant press William Withering English botanist, geologist, chemist and physician wrote popular books on British botany, and by describing the screw-down plant press (and the vasculum) he brought it to the attention of amateur naturalists in Britain around 1771. | https://en.wikipedia.org/wiki?curid=48955231 |
Morro Solar Group The () is a stratigraphic group of Mesozoic-aged sedimentary formations exposed near Lima, Peru. The groups formations more specifically of Berriasian and Valanginian age (Early Cretaceous) and overlies the Jurassic Puente Piedra Group and underlies the Cretaceous Pamplona Formation. The is intruded by sills of andesitic composition. Together with the Casma and Imperial Groups, the contains clastic volcanosedimentary material derivative of the Mesozoic Casma Volcanic Arc. The formations of the group hosts mostly local fossils which do not have counterparts for biochronological correlation in other regions. The formations of the are: La Herradura Formation (), whose sediments reflect a marine near-shore deposition environment, the Valanginian Salto del Fraile Formation (), and the Marcavilca Formation (). The Salto del Fraile Formation is equivalent to the basal part of the Huancané Formation found further inland. | https://en.wikipedia.org/wiki?curid=48955269 |
Yojiro Kimura is the authority for 58 taxa, such as "Hypericum hayatae" | https://en.wikipedia.org/wiki?curid=48963201 |
Scallion virus X (SVX) is a plant virus that infects "Allium chinense", the Chinese scallion. It is a member of the genus "Potexvirus". It is most closely related to "Narcissus mosaic virus". Its genome is 6987 nts long. | https://en.wikipedia.org/wiki?curid=48978405 |
German Society for Plant Sciences The (also known as German Botanical Society, Deutsche Botanische Gesellschaft, DBG) is a non-profit network for plant sciences and botany in the German-speaking area. It represents plant scientists, promotes scientific botany nationally and internationally. It was founded 1882 at Eisenach, Germany. In September 2015 it comprises 920 individual members and persons working or interested in plant science. It integrates all plant science disciplines, like plant ecology, plant biochemistry, plant genetics, evolution, plant physiology, morphology and taxonomy. The society supports young scientists, unites all generations and is member of the "Federation of European Societies for Plant Biology (FESPB)" and associate partner of the "European Plant Science Organisation (EPSO)". | https://en.wikipedia.org/wiki?curid=48991382 |
Heterofullerene Heterofullerenes are classes of fullerenes, at least one carbon atom is replaced by another element. Based on spectroscopy, substitutions have been reported with boron (borafullerenes), nitrogen (azafullerenes), oxygen, arsenic, germanium, phosphorus, silicon, iron, copper, nickel, rhodium and iridium. Reports on isolated heterofullerenes are limited to those based on nitrogen and oxygen. | https://en.wikipedia.org/wiki?curid=48995651 |
Chemoproteomics is an approach to discovering mechanisms for regulating biological pathways for the purpose of designing new pharmaceutical therapies. It is a chemical proteomic method for pharmacological discovery research. can enable drug discovery. It is a method for identifying protein targets and potential off-target activity. applies mass spectrometry to analyze proteomes and their functions. A linker molecule connects a small molecule chemical probe (or library of chemical probes) with an analytically detectable bead or other agent for detection or separation. This method is being used to assess the molecular mechanisms of enzymes, drugs and other small molecules in order to create Activity-Based protein profiles. | https://en.wikipedia.org/wiki?curid=48999251 |
Biotechnology Innovation Organization The (BIO) is the largest trade organization in the world that represents the biotechnology industry. On January 4, 2016 the Biotechnology Industry Organization changed its name to be the Biotechnology Innovation Organization. BIO holds a trade meeting each year in the United States, which are essential for the business development and partnering activities that are required in the biotechnology sector, in which it is expensive to develop products, timelines to develop products are long, and regulatory risks are high. In 2018 the BIO International Convention was held in Boston and was attended by 18,289 delegates from 49 states, the District of Columbia and Puerto Rico and 67 countries. The event also held over 46,916 One-On-One Partnering Meetings, becoming a Guinness World Records, Record Holder for the "Largest Business Partnering Event." It also holds regional partnering meetings, for example in China, India, and Europe. In 2018, BIO spent $9.87 million on lobbying the government of the United States. Past issues that BIO has lobbied on included the amending the Internal Revenue Code to provide an exception from the passive loss rules for investments in high-technology research small business pass-through entities, to include vaccines against seasonal influenza within the definition of taxable vaccines, and to extend, expand, and improve the qualifying therapeutic discovery project program that first became law in 2010 | https://en.wikipedia.org/wiki?curid=49001977 |
Biotechnology Innovation Organization Examples of its public lobbying efforts, include support for development of biofuels such as those produced from algae, genetically modified crops, strong intellectual property rights, and for a more efficient and predictable regulatory process for new food and drug products. In June 2013 BIO partnered with the Coalition of Small Business Innovators to lobby the U.S. government to modernize the U.S. tax code "to recognize and promote small business innovation as fundamental to the long-term growth of the U.S. economy". It is a member of The Alliance to Feed the Future, an umbrella network, the mission of which is to "raise awareness and improve understanding of the benefits & necessity of modern food production and technology in order to meet global demand". The "Right Mix Matters" campaign launched in 2019 targets diversity within biopharmaceutical company leadership, including ongoing assessment of diversity measures (gender, race, ethnicity, sexual orientation) and the provision of online tools aimed at assisting companies to achieve target diversity goals. BIOs members include companies that make Pharmaceutical drugs, biofuels, industrial enzymes, and genetically modified crops. As of 2016, it represents 1,100 biotech companies in all 50 U.S. states, which employ 1.61 million Americans and support an additional 3.4 million jobs. BIO was founded 1993 in Washington, D.C. and Carl B. Feldbaum was the president from BIO's founding until he retired in 2004, and was succeeded by James C | https://en.wikipedia.org/wiki?curid=49001977 |
Biotechnology Innovation Organization Greenwood Leadership of BIO is vested in a 100+ member board. As of 2019, John Maraganore, PhD., president and chief executive officer of Alnylam Pharmaceuticals, Inc., was chairman, and James Greenwood was president and CEO. Ron Cohen, CEO of Acorda, preceded Maraganore as chair, elected to the position in June 2015. The Biotechnology Heritage Award, presented annually at the (BIO) Annual International Convention by the (BIO) and the Science History Institute (formerly the Chemical Heritage Foundation), recognizes individuals who have made significant contributions to the development of biotechnology through discovery, innovation, and public understanding. | https://en.wikipedia.org/wiki?curid=49001977 |
Advanced Scientific Data Format (ASDF) is a proposed replacement to the FITS standard for astronomical images and other astronomical data. The metadata is contained in a YAML header followed by binary or ASCII data. The Flexible Image Transport System FITS standard is a widely used data format in astronomy that incorporates metadata and ascii or binary data in the same file. However, the FITS standard has several limitations that make it difficult to use for complicated and hierarchical data. For example, the FITS 'cards' have keywords limited to only 8 characters, which can make it difficult to properly describe the value associated with it and the value for each keyword and its comment cannot be longer than 68 characters. By using YAML, more sophisticated and nested data structures may be used in ASDF than FITS. | https://en.wikipedia.org/wiki?curid=49002199 |
Borafullerene Borafullerenes are a class of heterofullerenes in which the element substituting for carbon is boron. They are also a member of the boron carbides class of materials that include Tetrabor (B4C). | https://en.wikipedia.org/wiki?curid=49017613 |
TSUP family The 4-Toluene Sulfonate Uptake Permease (TSUP) family (TC# 2.A.102) is also referred to as the TauE/SafE/YfcA/DUF81 Family. Although its members have not been rigorously characterized, evidence is available that at least some members function in the transport of sulfur containing organic compounds. These include 4-toluene sulfonate which may be transported by the TsaS of "Cupriavidus necator" (TC# 2.A.102.1.1), sulfolactate which may be exported by the TauE protein of "Cupriavidus necator" (TC# 2.A.102.2.1) and sulfoacetate which may be exported by the SafE1 protein of "Neptuniibacter caesariensis" (TC# 2.A.102.2.2). Another member of the TSUP family, TsaS of "Comamonas testosteroni", has been reported to function in the uptake of 4-toluene sulfonate. None of these functional assignments can be considered to be certain. | https://en.wikipedia.org/wiki?curid=49033936 |
Adolph Speyer (28 April 1812, Arolsen – 14 October 1892, Rhoden, Waldeck ) was a German entomologist who specialised in Lepidoptera, especially Hesperiidae. Dr. wrote more than 70 papers on butterflies and their distribution. partial list | https://en.wikipedia.org/wiki?curid=49042865 |
Elqui-Limarí Batholith The is a group of plutons in the Andes of Chile and Argentina between the latitudes of 28 and 30° S. The plutons of the batholith were emplaced and cooled in the Late Paleozoic and the earliest Mesozoic. Some of the plutons were emplaced in a context of crustal thickening related to the San Rafael orogeny. Together with the Chilean Coastal Batholith and the Colangüil Batholith the is a remnant of the volcanic arcs that erupted the volcanic material of the Choiyoi Group. | https://en.wikipedia.org/wiki?curid=49050360 |
Coastal Batholith of central Chile The is a group of plutons in the Chilean Coast Range of Central Chile appearing contiguously from 33° S to 38° S. At a latitude of 40° S an outlying group of plutons of the batholith appear in a more eastward position in the Andes. Together with the Elqui-Limarí Batholith and the Colangüil Batholith, the is a remnant of the volcanic arcs that erupted the volcanic material of the Choiyoi Group. During the Permian the zone of arc magmatism moved from the Coastal Batholith 350 km inland reaching San Rafael about 280 million years ago. The batholith is emplaced amidst metamorphic rocks belonging to a Paleozoic accretionary complex. The northern parts are of the batholith are themselves intruded by Jurassic gabbros. Rocks of the batholith belong to the calc-alkaline magma series. | https://en.wikipedia.org/wiki?curid=49050847 |
Oxalotrophic bacteria are bacteria capable of using oxalate as their sole source of carbon and energy. Oxalate is the anion of a salt of oxalic acid; oxalotrophs often consume calcium oxalate. bacteria are often facultative methylotrophs. | https://en.wikipedia.org/wiki?curid=49057371 |
Clay chemistry is an applied subdiscipline of chemistry which studies the chemical structures, properties and reactions of or involving clays and clay minerals. It is a multidisciplinary field, involving concepts and knowledge from inorganic and structural chemistry, physical chemistry, materials chemistry, analytical chemistry, organic chemistry, mineralogy, geology and others. The study of the chemistry (and physics) of clays and clay minerals is of great academic and industrial relevance as they are among the most widely used industrial minerals, being employed as raw materials (ceramics, pottery, etc.), adsorbents, catalysts, additives, mineral charges, medicines, building materials and others. The unique properties of clay minerals including: nanometric scale layered construction, presence of fixed and interchangeable charges, possibility of adsorbing and hosting (intercalating) molecules, ability of forming stable colloidal dispersions, possibility of tailored surface and interlayer chemical modification and others, make the study of clay chemistry a very important and extremely varied field of research. Many distinct fields and knowledge areas are impacted by the phisico-chemical behavior of clay minerals, from environmental sciences to chemical process engineering, from pottery to nuclear waste management. Their cation exchange capacity (CEC) is of great importance in the balance of the most common cations in soil (Na, K, NH, Ca, Mg) and pH control, with direct impact on the soil fertility | https://en.wikipedia.org/wiki?curid=49059554 |
Clay chemistry It also plays an important role in the fate of most Ca arriving from land (river water) into the seas. The ability to change and control the CEC of clay minerals offers a valuable tool in the development of selective adsorbants with applications as varied as chemical sensors or pollution cleaning substances for contaminated water, for example. The understanding of the reactions of clay minerals with water (intercalation, adsorption, colloidal dispersion, etc.) are indispensable for the ceramic industry (plasticity and flow control of ceramic raw mixtures, for example). Those interactions also influence a great number of mechanical properties of soils, being carefully studied by building and construction engineering specialists. The interactions of clay minerals with organic substances in the soil also plays a vital role in the fixation of nutrients and fertility, as well as in the fixation or leaching of pesticides and other contaminants. Some clay minerals (Kaolinite) are used as carrier material for fungicides and insecticides. The weathering of many rock types produce clay minerals as one of its last products. The understanding of these geochemical processes is also important for the understanding of geological evolution of landscapes and macroscopic properties of rocks and sediments. Presence of clay minerals in Mars, detected by the Mars Reconnaissance Orbiter in 2009 was another strong evidence of the existence of water on the planet in previous geological eras | https://en.wikipedia.org/wiki?curid=49059554 |
Clay chemistry The possibility to disperse nanometric scaled clay mineral particles into a matrix of polymer, with the formation of an inorganic-organic nanocomposite has prompted a large resurgence in the study of these minerals from the late 1990s. In addition, study of clay chemistry is also of great relevance to the chemical industry, as many clay minerals are used as catalysts, catalyst precursors or catalyst substrates in a number of chemical processes, like automotive catalysts and oil cracking catalysts. | https://en.wikipedia.org/wiki?curid=49059554 |
Mécanique analytique (1788–89) is a two volume French treatise on analytical mechanics, written by Joseph-Louis Lagrange, and published 101 years following Isaac Newton's "Philosophiæ Naturalis Principia Mathematica". It consolidated into one unified and harmonious system, the scattered developments of contributors such as Alexis Clairaut, Jean le Rond d'Alembert, Leonhard Euler, and Johann and Jacob Bernoulli in the historical transition from geometrical methods, as presented in Newton's "Principia", to the methods of mathematical analysis. The treatise expounds a great labor-saving and thought-saving general analytical method by which every mechanical question may be stated in a single differential equation. Lagrange wrote that this work was entirely new and that his intent was to reduce the theory and the art of solving mechanics problems to general formulae, providing all the equations necessary for the solution of each problem. He stated that...No diagrams will be found in this work. The methods that I explain require neither geometrical, nor mechanical, constructions or reasoning, but only algebraical operations in accordance with regular and uniform procedure. Those who love Analysis will see with pleasure that Mechanics has become a branch of it, and will be grateful to me for having thus extended its domain. Ernst Mach describes the work as follows: Analytic mechanics... was brought to the highest degree of perfection... Lagrange's aim is.. | https://en.wikipedia.org/wiki?curid=49067628 |
Mécanique analytique to dispose, "once and for all", of the reasoning necessary to resolve mechanical problems, by embodying as much as possible of it in a single formula. This he did. Every case... can now be dealt with by a very simple... schema; and whatever reasoning is left is performed by purely mechanical methods. The mechanics of Lagrange is a stupendous contribution to the economy of thought. The work was first published in 1788 (volume 1) and 1789 (volume 2). Lagrange issued a substantially enlarged second edition of volume 1 in 1811, toward the end of his life. His revision of volume 2 was substantially complete at the time of his death in 1813, but was not published until 1815. The second edition of 1811/15 has been translated into English, and is available online at archive.org. | https://en.wikipedia.org/wiki?curid=49067628 |
Tethersonde A tethersonde is a radiosonde attached to a fixed or tethered balloon, used in atmospheric science. The balloon is usually larger than a balloon used for upper-air soundings, and the tether usually limits the sounding to the boundary layer. The radiosonde is typically moved up and down the tether to get multiple, high-resolution profiles of the boundary layer. | https://en.wikipedia.org/wiki?curid=49068504 |
Carbon Neutral Cities Alliance The (CNCA or “Alliance”) is a collaboration of leading global cities working to cut greenhouse gas emissions by 80% or more by 2050 or sooner (“80x50”) — the most aggressive greenhouse gas reduction targets undertaken by any cities across the globe. The Alliance aims to address what it will take for leading international cities to achieve these deep emissions reductions and how they can work together to meet their respective goals more efficiently and effectively. The Alliance was born in Copenhagen in June 2014 at an organizing meeting of the following 17 cities: Founding cities came together to share lessons in planning for and implementing deep carbon reductions and agreed upon opportunities to accelerate best practices through collaboration in the Alliance’s first year, including: The Alliance is staffed by the Urban Sustainability Directors Network (USDN) in partnership with the Innovation Network for Communities (INC) and C40 Cities Climate Leadership Group (C40), and is supported by The Kresge Foundation, Barr Foundation, Summit Foundation, Rockefeller Brothers Fund, V. Kann Rasmussen Foundation, MacArthur Foundation, and Bullitt Foundation. To read more and stay in touch with CNCA: | https://en.wikipedia.org/wiki?curid=49070718 |
Methane functionalization is the process of converting methane in its gaseous state to another molecule with a functional group, typically methanol or acetic acid, through the use of transition metal catalysts. In the realm of carbon-hydrogen bond activation and functionalization (C-H activation/functionalization), many recent efforts have been made in order to catalytically functionalize the C-H bonds in methane. The large abundance of methane in natural gas or shale gas deposits presents a large potential for its use as a feedstock in modern chemistry. However, given its gaseous natural state, it is quite difficult to transport economically. Its ideal use would be as a raw starting material for methanol or acetic acid synthesis, with plants built at the source to eliminate the issue of transportation. Methanol, in particular, would be of great use as a potential fuel source, and many efforts have been applied to researching the feasibilities of a methanol economy. The challenges of C-H activation and functionalization present themselves when several factors are taken into consideration. Firstly, the C-H bond is extremely inert and non-polar, with a high bond dissociation energy, making methane a relatively unreactive starting material. Secondly, any products formed from methane would likely be more reactive than the starting product, which would be detrimental to the selectivity and yield of the reaction | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization The main strategy currently used to increase the reactivity of methane uses transition metal complexes to activate the carbon-hydrogen bonds. In a typical C-H activation mechanism, a transition metal catalyst coordinates to the C-H bond to cleave it, and convert it into a bond with a lower bond dissociation energy. By doing so, the product can be used in further downstream reactions, since it will usually have a new functional group attached to the carbon. It is also important to note the difference between the terms "activation" and "functionalization," since both terms are often used interchangeably, but should be held distinct from each other. Activation refers to the coordination of a metal center to the C-H bond, whereas functionalization occurs when the coordinated metal complex is further reacted with a group "X" to result in the functionalized product. The four most common methods of transition metal catalyzed methane activation are the Shilov system, sigma bond metathesis, oxidative addition, and 1,2 addition reactions. The Shilov system involves platinum based complexes to produce metal alkyls. It was first discovered when a hydrogen-deuterium exchanged was observed in a deuterated solution with the platinum tetrachloride anion. Shilov et al. then was able to catalytically convert methane into methanol or methyl chloride when a Pt(IV) salt was used as a stoichiometric oxidant | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization The process is simplified down into three main steps: (1) C-H activation, (2) a redox reaction to form an octahedral intermediate, followed by (3) the formation of the carbon-oxygen bond to form methanol (). Sigma bond metathesis involves the formation of new C-H and metal-carbon bonds, where the metals are typically in the d configuration. Starting with a metal alkyl, a C-H bond coordinates with the metal complex via sigma bonding. A four-member transition state is created, where a new metal-carbon bond is formed, and the former C-H linkage is broken (). In oxidative addition, the metal center's oxidation state increases by 2 units during the process. First, the metal center coordinates with a sigma C-H bond to form an intermediate called a sigma-methane complex. The C-H linkage is then broken, as the metal becomes covalently bonded each to the carbon and the hydrogen (). Similar to sigma bond metathesis is the 1,2 addition reaction, where a four-membered transition state is also formed. However, a polarized double or triple metal-ligand bond is required in order to favor the formation of the desired product (). Once the C-H bond of methane is activated by bonding to a transition metal complex, the net functionalization of the alkyl metal complex into another hydrocarbon containing a functional group is actually much harder to achieve | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization In general, alkanes of various lengths have typically been functionalized by a number of more commonly known reactions: electrophilic activation (Shilov system, see above), dehydrogenation, borylation, hydrogen-deuterium exchange, and carbene/nitrene/oxo insertion. The functionalization of methane in particular has been reported in four different methods that use homogeneous catalysts rather than heterogeneous catalysts. Heterogeneous systems, using copper- and iron exchanged Zeolite, are also invesitgated. In these systems, reactive oxygen species such as Alpha-Oxygen are generated which can perform a hydrogen atom abstraction. In 1993, Periana et al. reported a synthesis of methyl bisulfate from methane using a mercury catalyst at 180 °C. Mercuric bisulfate activates methane electrophilically to form a methyl-complex, which then reacts with sulfuric acid to produce methyl bisulfate. The resulting mercury complex Hg(OSO) is re-oxidized by sulfuric acid to regenerate the catalyst and restart the catalytic cycle (). This method of functionalizing methane preceded the 1998 discovery by the same group of the so-called Catalytica system, the most active cycle to date in terms of turnover rate, yields, and selectivity. Performing the reaction in sulfuric acid at 220 °C means that the catalyst must be able to withstand these harsh conditions. A platinum-bipyrimidine complex serves as the catalyst | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization The mechanism for this system is similar to the one described above, where methane is first activated electrophilically to form a methyl-platinum intermediate. The Pt(II) complex is then oxidized to Pt(IV) as two sulfuric acid groups are added to the complex. The reductive elimination of methyl bisulfate transforms the Pt(IV) species back to Pt(II) to regenerate the catalyst (). In a hypothetical combined process, the Catalytica system could be used in a net conversion of methane to methanol. The methyl bisulfate produced in the cycle could be converted to methanol by hydrolysis, and the sulfur dioxide generated could be converted back to sulfuric acid. Periana's group was also able to convert methane into acetic acid using similar conditions to the Catalytica system. Palladium(II) salts were used in this process, and the products formed were a mixture of methanol and acetic acid, along with side products of carbon monoxide and possibly carbon dioxide due to over-oxidation. The mechanism of reaction involves another electrophilic activation of methane, and when carbon monoxide is incorporated, the acetic acid derivative is generated through its activation to an acyl intermediate (). Another example of acetic acid synthesis was demonstrated by Pombeiro et al., which utilized vanadium-based complexes in trifluoroacetic acid with peroxodisulfate as the oxidant. The proposed mechanism involves a radical mechanism, where methane is the methyl source and trifluoroacetic acid is the carbonyl source | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization Minor side products were formed, including methyltrifluoroacetate and methylsulfate. T. Don Tilley and coworkers were able to utilize the process of sigma-bond metathesis to design catalytic systems that work by the formation of carbon-carbon bonds. They first demonstrated an example using a scandium-based system, where methane is dehydrogenated and silated. Starting from phenyl silane, methane pressure converts it into PhMePhH using a Cp*ScMe catalyst. The scandium complex then transfers the methyl group to the silane by sigma-bond metathesis to form the product and the Cp*ScH intermediate. The favorable formation of hydrogen gas combined with methane will regenerate the methyl complex from the hydride derivative (). Cp*ScMe was also used as a catalyst in the formation of isobutane by adding methane to the double bond of propene. This was achieved when propene and methane were combined in the presence of the scandium catalyst and heated to 80 °C. Carbene insertion utilize a different strategy for the functionalization of methane. A strategy using metallocarbenes has been shown with several linear and branched alkanes with rhodium, silver, copper, and gold-based catalysts. With a carbene ligand attached to a metal center, it can be transferred from the coordination sphere and inserted into an activated C-H bond. In this case, there is no interaction between the metal center and the alkane in question, which separates this method from the other methods mentioned above | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization The general mechanism for this cycle begins with the reaction of an electron-poor metal center with a diazocompound to form a metallo-carbene intermediate. In order for this reaction to occur, the diazocompound must be very electrophilic, since the C-H bond is such a poor nucleophile as well as being an unactivated alkane. The reaction then proceeds in a concerted manner, where the C-H bond of the incoming molecule coordinates with the carbene carbon of the metallocarbene complex. The hydrocarbon then dissociates from the metal center to regenerate the catalyst and free the newly formed carbon-carbon bond (). This route is very successful for higher order alkanes due to the fact that there is no formation of strong metal-carbon or metal-hydrogen bonds that could prevent any intermediates from reacting further. The reactions also take place in room temperature under mild conditions. However, when applying this method to methane specifically, the gaseous nature of methane requires an appropriate solvent. Reactions with other alkanes usually have the alkane in question be the solvent itself; however, any C-H bond with a lower BDE or higher polarity than methane will react first and prevent methane functionalization. Therefore, Pérez, Asensio, Etienne, et al. developed a solution to use supercritical carbon dioxide as the solvent, which is formed under the critical pressure of 73 bar and a temperature of 31 °C | https://en.wikipedia.org/wiki?curid=49072305 |
Methane functionalization In these conditions, scCO behaves as a liquid, and since fluorinated compounds can dissolve easily in scCO, highly fluorinated silver-based catalysts were developed and tested with methane and ethyl diazoacetate. However, under the reaction conditions, only 19% yield of ethyl propionate was able to be achieved. The reaction depends on a delicate balance between methane pressure and catalyst concentration, and consequently more work is being done to further improve yields. | https://en.wikipedia.org/wiki?curid=49072305 |
Brazilian Journal of Geology (formerly Revista Brasileira de Geociências) is a quarterly peer-reviewed scientific journal published by the Sociedade Brasileira de Geologia, Brazil's main geology society. The journal covers the field of geology and related earth sciences, primarily on issues that are relevant to Brazil and nearby countries. The journal was established in 1971 and articles are published in English and Portuguese. The journal replaced the Boletim da Sociedade Brasileira de Geologia established in 1952. The journal is sponsored by Petrobras. | https://en.wikipedia.org/wiki?curid=49123152 |
Paranapanema block The is a coherent block of lithosphere located in southeastern South America spanning roughly the same area as the Paraná Basin. The existence of a tectonically stable zone beneath the Paraná Basin was first suggested in 1975. Despite difficulties in accessing the buried it is inferred it must be composed mostly of orthogneiss and the it existed before the Brasiliano orogeny. Paranapanema is a triangular block surrounded by structures of the Neoproterozoic Brasiliano orogeny. The northwestern edge faces the Paraguai Belt, probably the remains of an island arc from the Brazilides Ocean. On the northeast edge are the southern end of the Brasilia Belt and the Arenópolis magmatic arc. To the south and southeast are the Apiaí and São Roque belts. During the Carboniferous, Paranapanema was covered by sediments and during the Early Cretaceous, the Paraná-Etendeka large igneous province added a layer of flood basalts before the South America-Africa breakup. | https://en.wikipedia.org/wiki?curid=49131003 |
Adamastor Ocean The was a "proto-Atlantic" ocean that formed with the break-up of the Rodinia supercontinent around 780-750 Ma. It separated the Río de la Plata Craton from the Congo Craton. The inversion of the began about 640 Ma with the development of a large back-arc basin along the western margin of the Kalahari Craton, and the ocean closed when Río de la Plata collided with Kalahari about 545 Ma along the sinistral Sierra Ballena Shear Zone. The São Francisco plate and the Río de la Plata plate amalgamated 630–620 Ma, closing the on the South American side and forming the Mantiqueira Mountains around 600 Ma. South African geologist Chris Hartnady named the Precambrian ocean after the mythical giant Adamastor from Luís de Camões's poem "Os Lusíadas" which celebrates Vasco da Gama's discovery of the sea route to India. Hartnady thought it an appropiate name since the demigod was transformed into stone and personified the Cape of Storms and since Atlas and Iapetus are associated with the oceans of the northern Atlantic (the North Atlantic Ocean and the Iapetus Ocean respectively), | https://en.wikipedia.org/wiki?curid=49131449 |
Sparks-Thomas award The purpose of the Sparks-Thomas Award, given by the American Chemical Society, Rubber Division, is to recognize and encourage outstanding contributions and innovations in the field of elastomers by younger scientists, technologists, and engineers. Recipients | https://en.wikipedia.org/wiki?curid=49132760 |
Oscar Harger (January 12, 1843 – November 6, 1887) was an American invertebrate zoologist and paleontologist known for his studies on isopods, and for his work as an paleontological assistant to Othniel Charles Marsh. Harger, the son of Alfred Harger, a farmer and land surveyor of Huguenot descent, was born in Oxford, New Haven County, Conn, January 12, 1843. He graduated from Yale College in 1868. He was obliged throughout his college course to maintain himself by teaching and mathematical work, and he perhaps injured his health permanently by the severe economy which he practiced at that time. In his boyhood he had been an enthusiastic student of botany, and his success in this department of natural history led him on graduation to take up the study of zoology with Professor Verrill of the Sheffield Scientific School. He had already shown his special aptitude for original work and had begun important investigations, when he accepted in 1870 the position of Assistant in Paleontology under Professor Marsh, which he retained until his death. He continued, however, his investigations in invertebrate zoology, as long as his health allowed; of his publications in this field the most important is a valuable "Report on the Marine Isopoda of New England and the Adjacent Waters" (in the "Report of the United States Commissioner of Fish and Fisheries" for 1878). His best work and highest attainments, however, were in the department of vertebrate paleontology | https://en.wikipedia.org/wiki?curid=49148279 |
Oscar Harger In 1879 he was attacked by cardiac trouble, which increased from year to year. He continued engaged in his regular duties, until prostrated by cerebral hemorrhage on Monday, October 31, 1887. He died on the following Sunday, November 6, in his 45th year. He married, May 13, 1875, Jessie Craig, of New Haven, who survived him without children. He is commemorated in the genus "Hargeria", a fossil bird, and the species "Miacis hargeri", an extinct carnivorous mammal. | https://en.wikipedia.org/wiki?curid=49148279 |
All Sky Automated Survey for SuperNovae The (ASAS-SN) is an automated program to search for new supernovae and other astronomical transients, headed by astronomers from the Ohio State University. It has 20 robotic telescopes in both the northern and southern hemispheres. It can survey the entire sky approximately once every day. Initially, there were four ASAS-SN telescopes at Haleakala and another four at Cerro Tololo, a Las Cumbres Observatory site. Twelve more telescopes were deployed in 2017 in Chile, South Africa and Texas, with funds from the Gordon and Betty Moore Foundation, the Ohio State University, the Mount Cuba Astronomical Foundation, China, Chile, Denmark, and Germany. All the telescopes (Nikon telephoto f400/2.8 lenses) have a diameter of 14 cm and ProLine PL230 CCD cameras. The pixels in the cameras span 7.8 arc seconds, so follow up observations on other telescopes are usually required to get a more accurate location. The main goal of the project is to look for bright supernovae, and its discoveries have included the most powerful supernova event ever discovered, ASASSN-15lh. However, other transient objects are frequently discovered, including nearby tidal disruption events (TDEs) (e.g., ASASSN-19bt), Galactic novae (e.g., ASASSN-16kt, ASASSN-16ma, and ASASSN-18fv), cataclysmic variables, and stellar flares, including several of the largest flares ever seen. In July 2017 ASAS-SN discovered its first comet, ASASSN1, and in July 2019 it provided crucial data for the near-Earth asteroid 2019 OK | https://en.wikipedia.org/wiki?curid=49151754 |
All Sky Automated Survey for SuperNovae It can detect new objects with magnitudes between 18 and 8. Objects discovered receive designations starting with "ASASSN" followed by a dash, a two digit year and letters, for example ASASSN-19bt. | https://en.wikipedia.org/wiki?curid=49151754 |
Sulfide intrusion In ecology, sulfide intrusion refers to an excess of sulfide molecules (S) in the soil that interfere with plant growth, often seagrass. Seagrass bed sediment (soil) is typically anoxic, containing a reduced form of sulfur: hydrogen sulfide (HS). HS is a phytotoxin that results from anaerobic digestion, the decomposition of organic matter in the absence of oxygen. However, seagrass can persist in this environment because of physiological adaptations, as well as functional adaptations of other organisms in the ecosystem. For example, bivalves (clams) in the family Lucinidae host symbiotic bacteria that oxidize sulfides. Lucinid bivalves' gills house the bacteria, and the siphon supplies the bacteria and surrounding pore water with oxygenated water from above the sediment. Bacterial oxidation of the sulfides results in sulfates, reducing toxicity. | https://en.wikipedia.org/wiki?curid=49158055 |
APC Family The Amino Acid-Polyamine-Organocation (APC) Family (TC# 2.A.3) of transport proteins includes members that function as solute:cation symporters and solute:solute antiporters. They occur in bacteria, archaea, fungi, unicellular eukaryotic protists, slime molds, plants and animals. They vary in length, being as small as 350 residues and as large as 850 residues. The smaller proteins are generally of prokaryotic origin while the larger ones are of eukaryotic origin. Most of them possess twelve transmembrane α-helical spanners but have a re-entrant loop involving TMSs 2 and 3. The APC Superfamily was established to encompass a wider range of homologues. Members of one subfamily within the APC family (SGP; TC# 2.A.3.9) are amino acid receptors rather than transporters and are truncated at their C-termini, relative to the transporters, having 10 TMSs. The eukaryotic members of another subfamily (CAT; TC# 2.A.3.3) and the members of a prokaryotic subfamily (AGT; TC #2.A.3.11) have 14 TMSs. The larger eukaryotic and archaeal proteins possess N- and C-terminal hydrophilic extensions. Some animal proteins, for example, those in the LAT subfamily (TC# 2.A.3.8) including ASUR4 (gbY12716) and SPRM1 (gbL25068) associate with a type 1 transmembrane glycoprotein that is essential for insertion or activity of the permease and forms a disulfide bridge with it. These glycoproteins include the CD98 heavy chain protein of "Mus musculus (gbU25708)" and the orthologous 4F2 cell surface antigen heavy chain of "Homo sapiens (spP08195) | https://en.wikipedia.org/wiki?curid=49159269 |
APC Family " The latter protein is required for the activity of the cystine/glutamate antiporter (2.A.3.8.5), which maintains cellular redox balance and cysteine/glutathione levels. They are members of the rBAT family of mammalian proteins (TC #8.A.9). Two APC family members, LAT1 and LAT2 (TC #2.A.3.8.7), transport a neurotoxicant, the methylmercury-L-cysteine complex, by molecular mimicry. Hip1 of "S. cerevisiae" (TC #2.A.3.1.5) has been implicated in heavy metal transport. Subfamilies of the APC family, and the proteins in these families, can be found in the Transporter Classification Database: Based on 3-D structures of APC superfamily members, Rudnick (2011) has proposed the pathway for transport and suggested a ""rocking bundle"" mechanism. Transport reactions generally catalyzed by APC Superfamily members include: | https://en.wikipedia.org/wiki?curid=49159269 |
AGCS family Members of the Alanine or Glycine:Cation Symporter (AGCS) Family (TC# 2.A.25) transport alanine and/or glycine in symport with Na and or H. Known proteins in the are between 445 and 550 amino acyl residues in length and possess 8 to 12 putative transmembrane α-helical spanners. Members may possess 11 transmembrane segments (TMSs), as seems to be true for DagA (TC# 2.A.25.1.1) and AgcS (TC# 2.A.25.1.3), although Acp (TC# 2.A.25.1.2) has only 8 TMSs, perhaps the result of truncation. As of early 2016, there does not appear to be any 3D crystal structure data available for these proteins. Members of the have been found in bacteria and archaea, such as extremophile halotolerant cyanobacterium "Aphanothece halophytica," and thermophilic bacteria, "Bacillus" "PS3". As of 2015, only three members of the family have been functionally characterized. These proteins show limited sequence similarity in the APC family (TC# 2.A.3). As of early 2016, there do not appear to be any crystal structures available for members of the AGCS family. The generalized transport reaction catalyzed by the is: alanine or glycine (out) + Na or H (out) → alanine or glycine (in) + Na or H (in). There are currently 10 proteins belonging to the AGCS family. These proteins and their descriptions can be found in the Transporter Classification Database. | https://en.wikipedia.org/wiki?curid=49162176 |
Tac-Promoter The (abbreviated as Ptac), or tac vector is a synthetically produced DNA promoter, produced from the combination of promoters from the trp and lac operons. It is commonly used for protein production in Escherichia coli. Two hybrid promoters functional in Escherichia coli were constructed. These hybrid promoters, tacI and tacII, were derived from sequences of the trp and the lac UV5 promoters. In the first hybrid promoter (tacI), the DNA upstream of position -20 with respect to the transcriptional start site was derived from the trp promoter. The DNA downstream of position -20 was derived from the lac UV5 promoter. In the second hybrid promoter (tacII), the DNA upstream of position -11 at the Hpa I site within the Pribnow box was derived from the trp promoter. The DNA downstream of position -11 is a 46-base-pair synthetic DNA fragment that specifies part of the hybrid Pribnow box and the entire lac operator. It also specifies a Shine-Dalgarno sequence flanked by two unique restriction sites (portable Shine-Dalgarno sequence). The tacI and the tacII promoters respectively direct transcription approximately 11 and 7 times more efficiently than the derepressed parental lac UV5 promoter and approximately 3 and 2 times more efficiently than the trp promoter in the absence of the trp repressor. Both hybrid promoters can be repressed by the lac repressor and both can be derepressed with isopropyl-beta-D-thiogalactoside | https://en.wikipedia.org/wiki?curid=49172614 |
Tac-Promoter Consequently, these hybrid promoters are useful for the controlled expression of foreign genes at high levels in E. coli. In contrast to the trp and the lac UV5 promoters, the tacI promoter has not only a consensus -35 sequence but also a consensus Pribnow box sequence. This may explain the higher efficiency of this hybrid promoter with respect to either one of the parental promoters. The tac promoter is used to control and increase the expression levels of a target gene and is used in the over-expression of recombinant proteins. The tac promoter is named after the two promoters which comprise its sequence: the 'trp' and the 'lac' promoters. Bacterial promoters consist of two parts, the '-35' region and the '-10' region (the Pribnow box). These two regions bind the sigma factor of RNA polymerase, which then initiates transcription of the downstream gene. The tac promoter consists of the '-35' region of the trp promoter and the '-10' region of the lac promoter (and differs from the trc promoter by 1 bp). The tac promoter is, therefore, inducible by IPTG (Isopropyl β--1-thiogalactopyranoside), whilst also allowing higher maximum gene expression than either the lac or trp promoters. This makes it suitable for high-efficiency protein production of a recombinant protein. The strong repression of expression in the 'off' state is important since foreign proteins can be toxic to the host cell. The tac promoter finds various applications | https://en.wikipedia.org/wiki?curid=49172614 |
Tac-Promoter The tac promoter/operator (dubbed "PTAC") is one of the most widely used expression systems. Ptac is a strong hybrid promoter composed of the -35 region of the trp promoter and the -10 region of the lacUV5 promoter/operator. Expression of PTAC is repressed by the lacI protein. The lacI allele is a promoter mutation that increases the intracellular concentration of LacI repressor, resulting in the strong repression of PTAC. An addition of the inducer IPTG inactivates the LacI repressor. Thus, the amount of expression from PTAC is proportional to the concentration of IPTG added: low concentrations of IPTG result in relatively low expression from PTAC and high concentrations of IPTG result in high expression from PTAC. By varying the IPTG concentration the amount of gene product cloned downstream from PTAC can be varied over several orders of magnitude. For example, the PTAC system is used for fusion protein expression within the PMAL-C2X expression. | https://en.wikipedia.org/wiki?curid=49172614 |
Mithan Lal Roonwal (18 September 1908 – 22 July 1990) was an Indian zoologist and director of the Zoological Survey of India. Roonwal studied a range of taxa from termites to mammals. His landmark works were on the biology of termites and a monograph on the primates of South Asia. He was the first to note geographic patterns in the shape in which gray langurs (treated in his time as a single species) carried their tails. He described many new species during his career at the Zoological Survey of India. Roonwal was born in Jodhpur where he received his early education. He then studied at Lucknow where he obtained a Master of Science in 1930. He began work at the Locust Research Institute in 1931 at Lyallpur and went to Cambridge where he worked on the embryology of "Schistocerca gregaria" under the guidance of Augustus Daniel Imms and obtained a Ph.D. in 1935. He joined the Zoological Survey of India where he worked at the birds and mammals section from 1939 to 1940. Roonwal joined the army during the Second World War and served as a Major in the 5th Punjab Regiment and received a Burma Star for his services. From 1946 he continued his studies on the desert locust and published ideas on predicting the formation of swarms. He joined the Forest Research Institute in 1949 as an entomologist and worked on cataloguing the insect collections held there. He continued working there until 1956 during which time he took an interest in the systematics of termites in which he collaborated with Alfred E. Emerson | https://en.wikipedia.org/wiki?curid=49174555 |
Mithan Lal Roonwal In 1956 he joined the Zoological Survey of India to succeed Sunder Lal Hora as the director. He retired from the ZSI in 1965 and joined Jodhpur University. He received a Sc.D. for his work on the morphology and systematics of termites in 1962 from Cambdrige University. | https://en.wikipedia.org/wiki?curid=49174555 |
NGC 4490 NGC 4490, also known as the Cocoon Galaxy, is a barred spiral galaxy in the constellation Canes Venatici. It lies at a distance of 25 million light years from Earth. It interacts with its smaller companion NGC 4485 and as a result is a starburst galaxy. and NGC 4485 are collectively known in the Atlas of Peculiar Galaxies as Arp 269. is located 3/4° northwest of beta Canum Venaticorum and with apparent visual magnitude 9.8, can be observed with 15x100 binoculars. It is a member of Herschel 400 Catalogue. It belongs in Canes Venatici galaxy cloud II. It was discovered by William Herschel in 1788. Two supernovae have been observed in NGC 4490, SN 1982F, and type II-P SN 2008ax, with peak magnitude 16.1. | https://en.wikipedia.org/wiki?curid=49200995 |
Innermost stable circular orbit The innermost stable circular orbit (often called the ISCO) is the smallest circular orbit in which a test particle can stably orbit a massive object in general relativity. The location of the ISCO, the ISCO-radius (formula_1), depends on the angular momentum (spin) of the central object. The ISCO plays an important role in black hole accretion disks since it marks the inner edge of the disk. For a non-spinning massive object, where the gravitational field can be expressed with the Schwarzschild metric, the ISCO is located at, where formula_3 is the Schwarzschild radius of the massive object with mass formula_4. Thus, even for a non-spinning object, the ISCO radius is only three times the Schwarzschild radius, formula_5, suggesting that only black holes and neutron stars have innermost stable circular orbits outside of their surfaces. As the angular momentum of the central object increases, formula_1 decreases. Circular orbits are still possible between the ISCO and the photon sphere, but they are unstable. The photon sphere has a radius of For a massless test particle like a photon, the only possible circular orbit is exactly at the photon sphere, and is unstable. Inside the photon sphere, no circular orbits exist. The case for rotating black holes is somewhat more complicated. The equatorial ISCO in the Kerr metric depends on whether the orbit is prograde (negative sign below) or retrograde (positive sign): where with formula_11 as the rotation parameter | https://en.wikipedia.org/wiki?curid=49203606 |
Innermost stable circular orbit As the rotation rate of the black hole increases the retrograde ISCO increases towards formula_12 (4.5 times the a=0 horizon radius) while the prograde ISCO decreases towards the horizon radius and appears to merge with it for an extremal black hole (however, this later merger is illusory and an artefact of using Boyer-Lindquist coordinates ). If the particle is also spinning there is a further split in ISCO radius depending on whether the spin is aligned with or against the black hole rotation. | https://en.wikipedia.org/wiki?curid=49203606 |
NGC 2768 is a lenticular galaxy located in the constellation of Ursa Major. It is at a distance of 65 million light years from Earth. is an example of a Seyfert galaxy, an object with a supermassive black hole at its centre. A dusty structure is encircling the centre of the galaxy, forming a knotted ring around the galaxy's brightly glowing middle. This ring lies perpendicular to the plane of itself, stretching up and out of the galaxy. The dust in forms an intricate network of knots and filaments. In the centre of the galaxy are two tiny, S-shaped symmetric jets. These two flows of material travel outwards from the galactic centre along curved paths, and are masked by the tangle of dark dust lanes that spans the body of the galaxy. These jets are a sign of a very active centre, where lies a supermassive black hole. This speeds up and sucks in gas from the nearby space, creating a stream of material swirling inwards towards the black hole known as an accretion disc. This disk throws off material in very energetic outbursts, creating structures like the jets. has had one observed Type Ib supernova, designated SN2000ds, which occurred far from the nuclear region. | https://en.wikipedia.org/wiki?curid=49207552 |
HAAAP family The Hydroxy/Aromatic Amino Acid Permease (HAAAP) Family (TC# 2.A.42) is a member of the large Amino Acid-Polyamine-OrganoCation (APC) Superfamily of secondary carriers. Members of the all function in amino acid uptake. Homologues are present in a large number of Gram-negative and Gram-positive bacteria, with at least one member classified from archaea (TC# 2.A.42.1.7, "Thermococcus barophilus")"." Proteins of the possess 403-443 amino acyl residues and exhibit eleven putative or established transmembrane α-helical spanners (TMSs). These proteins exhibit topological features common to the eukaryotic amino acid/auxin permease (AAAP) family (TC# 2.A.18). These proteins also exhibit limited sequence similarity with some of the AAAP family members. A phylogenetic relationship has been proposed between members of the and APC family since they exhibit limited sequence similarity with one another. As of early 2016, there is no crystal structural data available for members of the in RCSB. The includes three well-characterized aromatic amino acid:H symport permeases of "E. coli": a high affinity tryptophan-specific permease, Mtr (TC# 2.A.42.1.2), a low affinity tryptophan permease, TnaB (TC# 2.A.42.1.3), and a tyrosine-specific permease, TyrP (TC# 2.A.42.1.1), as well as two well-characterized hydroxy amino acid permeases, the serine permease, SdaC (TC# 2.A.42.2.1), of "E. coli", and the threonine permease, TdcC (TC# 2.A.42.2.2), of "E. coli". SdaC of "E. coli" (TC# 2.A.42.2 | https://en.wikipedia.org/wiki?curid=49219918 |
HAAAP family 1) is also called DcrA, and together with a periplasmic protein DcrB (P37620), has been reported to play a role in phage DNA uptake in conjunction with an outer membrane receptor of the OMR family (TC# 1.B.14). Thus, FhuA (TC #1.B.14.1.4) transports phage T5 DNA while BtuB (TC# 1.B.14.3.1) transports phage C1 DNA (Samsonov et al., 2002). DcuB is a putative lipoprotein found only in enteric bacteria. All members of the can be found in the Transporter Classification Database. The generalized transport reaction catalyzed by proteins of the is: Amino acid (out) + nH (out) → Amino acid (in) + nH (in). | https://en.wikipedia.org/wiki?curid=49219918 |
Weak gravity conjecture The weak gravity conjecture (WGC) is a conjecture regarding the strength gravity can have in a theory of quantum gravity relative to the gauge forces in that theory. It roughly states that gravity should be the weakest force in any consistent theory of quantum gravity. | https://en.wikipedia.org/wiki?curid=49226157 |
Dienyl radical Dienyl radicals are free radicals that can be formed by the oxidation of polyunsaturated fatty acids. These can combine with oxygen to form cis-trans lipid peroxyl radicals. | https://en.wikipedia.org/wiki?curid=49250685 |
Holmium–magnesium–zinc quasicrystal A holmium–magnesium–zinc (Ho–Mg–Zn) quasicrystal is a quasicrystal made of an alloy of the three metals holmium, magnesium and zinc that has the shape of a regular dodecahedron, a Platonic solid with 12 five-sided faces. Unlike the similar pyritohedron shape of some cubic-system crystals such as pyrite, this quasicrystal has faces that are true regular pentagons. | https://en.wikipedia.org/wiki?curid=49253469 |
EcoRI "Eco"RI (pronounced "eco R one") is a restriction endonuclease enzyme isolated from species "E. coli." The "Eco" part of the enzyme's name originates from the species from which it was isolated, while the R represents the particular strain, in this case RY13. The last part of its name, the I, denotes that it was the first enzyme isolated from this strain. "Eco"RI is a restriction enzyme that cleaves DNA double helices into fragments at specific sites. It is also a part of the restriction modification system. In molecular biology it is used as a restriction enzyme. "Eco"RI creates 4 nucleotide sticky ends with 5' end overhangs of AATT. The nucleic acid recognition sequence where the enzyme cuts is G/AATTC, which has a palindromic, complementary sequence of CTTAA/G. The / in the sequence indicates which phosphodiester bond the enzyme will break in the DNA molecule. Other restriction enzymes, depending on their cut sites, can also leave 3' overhangs or blunt ends with no overhangs. "Eco"RI contains the PD..D/EXK motif within its active site like many restriction endonucleases. The enzyme is a homodimer of a 31 kilodalton subunit consisting of one globular domain of the α/β architecture. Each subunit contains a loop which sticks out from the globular domain and wraps around the DNA when bound. "Eco"RI has been cocrystallized with the sequence it normally cuts. This crystal was used to solve the structure of the complex | https://en.wikipedia.org/wiki?curid=49256303 |
EcoRI The solved crystal structure shows that the subunits of the enzyme homodimer interact with the DNA symmetrically. In the complex, two α-helices from each subunit come together to form a four-helix bundle. On the interacting helices are residues Glu144 and Arg145, which interact together, forming a crosstalk ring that is believed to allow the enzyme's two active sites to communicate. Restriction enzymes, such as "Eco"RI, are used in a wide variety of molecular genetics techniques including cloning, DNA screening and deleting sections of DNA "in vitro". Restriction enzymes, like "Eco"RI, that generate sticky ends of DNA are often used to cut DNA prior to ligation, as the sticky ends make the ligation reaction more efficient. "Eco"RI can exhibit non-site-specific cutting, known as star activity, depending on the conditions present in the reaction. Conditions that can induce star activity when using "Eco"RI include low salt concentration, high glycerol concentration, excessive amounts of enzyme present in the reaction, high pH and contamination with certain organic solvents. The cut made by the Eco RI enzyme produces sticky ends on the vector mainly plasmids or viral DNA's. | https://en.wikipedia.org/wiki?curid=49256303 |
Glacial stream A glacial stream is a channelized accumulation of liquid water which flow in a channel formed by a glacier. Depending on where they flow, they can be classified into supraglacial, englacial and subglacial streams. | https://en.wikipedia.org/wiki?curid=49266988 |
Robert Chinnock Robert James "Bob" Chinnock (born 3 July 1943) is a New Zealand-born Australian botanist who worked at the State Herbarium of South Australia as a senior biologist. He retired in 2008 but still works as an honorary research associate. His research interests include "Eremophila" and related genera, the weedy Cactaceae, especially those in the genus "Opuntia", and Australian ferns and clubmosses. His PhD thesis at Flinders University in 1982 was focused upon Myoporaceae, He is the author of "Eremophila and allied genera : a monograph of the plant family Myoporaceae". (Plants in these genera are now included in the family Scrophulariaceae.) | https://en.wikipedia.org/wiki?curid=49273226 |
Helmut Gams (1893–1976) was a central European botanist. Born in Brno, he moved to Zürich as a child. He studied at the University of Zurich, being awarded a PhD in 1918. During his career, he worked at the University of Munich and the University of Innsbruck. His research saw him pursue fieldwork around Europe and Asia. He specialized in mosses and lichens. | https://en.wikipedia.org/wiki?curid=49278031 |
NGC 986 is a barred spiral galaxy in the constellation of Fornax, located about 56 million light-years away. The galaxy contains two large, extended and slightly warped arms that begin at each end of the central bar. It was discovered in 1826 by the Scottish astronomer James Dunlop. | https://en.wikipedia.org/wiki?curid=49287387 |
Nicotinamide ribonucleoside uptake transporters The Nicotinamide Ribonucleoside (NR) Uptake Permease (PnuC) Family (TC# 4.B.1) is a family of transmembrane transporters that is part of the TOG superfamily. Close PnuC homologues are found in a wide range of Gram-negative and Gram-positive bacteria, archaea and eukaryotes. PnuC of "Salmonella typhimurium" and "Haemophilus influenzae" are believed to function cooperatively with NadR homologues, multifunctional proteins that together with PnuC, participate in NR phosphorylation, transport and transcriptional regulation. NadR, a cytoplasmic protein that is partly membrane associated, contains one well conserved and one poorly conserved mononucleotide-binding consensus sequence (G-X4 GKS). It drives transport and may render transport responsive to internal pyridine nucleotide levels. While its N-terminal half functions as a repressor, its C-terminal half functions as an NR kinase in a putative group translocation process. The "H. influenzae" homologue has been shown to transport NR from the periplasm into the cytoplasm. Phosphorylation of NR by NadR is required for NR uptake. The ribonucleoside kinase (RNK) domain has both Walker A and Walker B motifs, responsible for ATP binding and phosphoryl transfer. In addition, a proposed LID domain was identified in RNK. LID domains have been found in other kinases, and these domains are regions which are able to move after substrate binding | https://en.wikipedia.org/wiki?curid=49292515 |
Nicotinamide ribonucleoside uptake transporters They are responsible for coordination of three distinct conformations, an open state in the absence of substrate, a partially closed state after substrate binding, and a fully closed state when both substrates are present. In "H. influenzae", NR enters the NAD resynthesis pathway after phosphorylation to NMN, and subsequently, NAD is synthesized from NMN and ATP via an NMN adenylyl transferase activity. NadR represents a multifunctional regulator/enzyme complex able to integrate several functions, such as enzymatic catalysis, transport, and transcriptional regulatory activities. The components of the "H. influenzae" pathway necessary for NAD, NMN, and NR uptake have been determined. Merdanovic et al. characterized two enzymes, an outer membrane nucleotide phosphatase, and an NAD nucleotidase (NadN) located in the periplasm. They showed that NAD and NMN cross the outer membrane mainly via the OmpP2 porin. Only NR can be utilized by the PnuC transport system located in the inner membrane. The "pnuC" gene product is the protein that is responsible for the main flow of the NR substrate into the cytoplasm. The study of Merdanovic et al. suggests that the RNK activity of NadR determines NR transport and is negatively regulated by cytoplasmic NAD feedback inhibition. Therefore, NR uptake is under NadR feedback control. ATP, not the proton motive force, appears to be required for NR uptake. Thus, the driving force for NR uptake via PnuC is NR phosphorylation by NadR | https://en.wikipedia.org/wiki?curid=49292515 |
Nicotinamide ribonucleoside uptake transporters A concerted group translocation mechanism can be considered whereby NadR facilitates the dissociation of NR from PnuC by phosphorylating it to NMN, thus preventing efflux of NR. The proposed transport reaction catalyzed by PnuC and NadR is: NR (out) + ATP (in) → NMN (in) + ADP (in). PnuC of "Salmonella typhimurium" and "Haemophilus influenzae" are integral membrane proteins, 239 and 226 amino acyl residues (aas) in length, respectively, with 7 putative transmembrane α-helical segments. The structure of NadR has been determined. Mutations in the "nadR" gene which interfere with NR uptake occur in the C-terminal part of NadR. A helix-turn-helix DNA binding domain present in NadR of "S. enterica serovar Typhimurium" could not be found in the NadR homologue of "H. influenzae". Therefore, it was proposed that in "H. influenzae" NadR has no regulatory function at the transcriptional level. The structures of the human NR kinase 1 (2QL6_P) with nucleotide and nucleoside substrates bound have been solved. It is structurally similar to Rossmann fold metabolite kinases. PnuC has been shown to resemble SWEET porters in overall fold, supporting the conclusion that these two families are members of the TOG superfamily. NadR Protein from "H. influenzae" NR transporter PnuC | https://en.wikipedia.org/wiki?curid=49292515 |
Andrew Phillip Brown (born 1951) is a conservation biologist and taxonomist at the Western Australian Department of Environment and Conservation. He is also curator of Orchidaceae and Myoporaceae at the Western Australian Herbarium and a foundation member of the Australian Orchid Foundation and the Western Australia Native Orchid Study and Conservation Group. He is the author of more than 100 journal articles and seven books on the flora of Western Australia including a field guide to the eremophilas of that state. | https://en.wikipedia.org/wiki?curid=49292835 |
Natural resistance-associated macrophage protein Natural resistance-associated macrophage proteins (NRAMPs) are members of the metal ion (Mn-iron) transporter family (TC# 2.A.55). The NRAMP family is a member of the large APC Superfamily of secondary carriers. Homologues of this family are found in various yeasts, plants, animals, archaea, and Gram-negative and Gram-positive bacteria termed "natural resistance-associated" macrophage proteins because one of the animal homologues plays a role in resistance to intracellular bacterial pathogens such as "Salmonella enterica serovar Typhimurium", "Leishmania donovani" and "Mycobacterium bovis". The natural history of "SLC11" genes in vertebrates has been discussed by Neves et al. (2011). Proposed to be a distant member of the APC Superfamily, several human pathologies may result from defects in NRAMP-dependent Fe or Mn transport, including iron overload, neurodegenerative diseases and innate susceptibility to infectious diseases. Humans and rodents possess two distinct NRAMPs. The broad specificity NRAMP2 (DMT1), which transports a range of divalent metal cations, transports Fe and H with a 1:1 stoichiometry and apparent affinities of 6 μm and about 1 μm, respectively. Variable H:Fe stoichiometry has also been reported. The order of substrate preference for NRAMP2 is: Fe> Zn> Mn> Co> Ca> Cu> Ni> Pb Many of these ions can inhibit iron absorption. Mutation of NRAMP2 in rodents leads to defective endosomal iron export within the ferritin cycle, impaired intestinal iron absorption and microcytic anemia | https://en.wikipedia.org/wiki?curid=49293529 |
Natural resistance-associated macrophage protein Symptoms of Mn deficiency are also seen. It is found in apical membranes of intestinal epithelial cells but also in late endosomes and lysosomes. In contrast to the widely expressed NRAMP2, NRAMP1 is expressed primarily in macrophages and monocytes and appears to have a preference for Mn rather than Fe. NRAMP1 (TC# 2.A.55.2.3) has been reported to function by metal:H antiport. It is hypothesized that a deficiency for Mn or some other metal prevents the generation of reactive oxygenic and nitrogenic compounds that are used by macrophage to combat pathogens. This hypothesis is supported by studies on the bacterial NRAMP homologues which exhibit extremely high selectivity for Mn over Fe, Zn and other divalent cations. Regulation of these transporters in bacteria can occur through Fur, OxyR, and most commonly a DtxR homolog, MntR. The Smf1 protein of "Saccharomyces cerevisiae" appears to catalyze high-affinity ("K" = 0.3 μm) Mn uptake while the closely related Smf2 protein may catalyze low affinity ("K" = 60 μm) Mn uptake in the same organism. Both proteins also mediate H-dependent Fe uptake. These proteins are of 575 and 549 amino acyl residues in length and are predicted to have 8-12 transmembrane α-helical spanners. The "E. coli" homologue of 412 aas exhibits 11 putative and confirmed TMSs with the N-terminus in and the C-terminus out. The yeast proteins may be localized to the vacuole and/or the plasma membrane of the yeast cell | https://en.wikipedia.org/wiki?curid=49293529 |
Natural resistance-associated macrophage protein Indirect and some direct experiments suggest that they may be able to transport several heavy metals including Mn, Cu, Cd and Co. A third yeast protein, Smf3p, appears to be exclusively intracellular, possibly in the Golgi. NRAMP2 ("Slc11A2") of Homo sapiens (TC# 2.A.55.2.1) has a 12 TMS topology with intracellular N- and C-termini. Two-fold structural symmetry in the arrangement of membrane helices for TM1-5 and TM6-10 (conserved Slc2 hydrophobic core) is suggested. The generalized transport reaction catalyzed by NRAMP family proteins is: Me (out) + H (out) ⇌ Me (in) + H (in). All Nramp proteins have eleven to twelve transmembrane helices, the first ten of which form a canonical LeuT fold, common throughout the APC superfamily. Metal uptake in Nramp proteins is typically stimulated by acidic pH and accompanied by proton influx, although many homologs have also shown proton uniport. This has been explained in the "Deinococcus radiodurans" homolog as the result of spatially segregated metal and proton pathways that rely on a longer-range allosteric connection rather than the direct structural connection seen in canonical symporters. Metal uptake requires alternating access bulk conformation change, in which the protein changes from an outward-open state to an inward-open state upon metal binding, while proton uptake can occur through a simpler channel-like mechanism. | https://en.wikipedia.org/wiki?curid=49293529 |
Rayleigh fractionation describes the evolution of a system with multiple phases in which one phase is continuously removed from the system through fractional distillation. It is used in particular to describe isotopic enrichment or depletion as material moves between reservoirs in an equilibrium process. holds particular importance in hydrology and meteorology as a model for the isotopic differentiation of meteoric water due to condensation. The original Rayleigh equation was derived by Lord Rayleigh for the case of fractional distillation of mixed liquids. This is an exponential relation that describes the partitioning of isotopes between two reservoirs as one reservoir decreases in size. The equations can be used to describe an isotope fractionation process if: (1) material is continuously removed from a mixed system containing molecules of two or more isotopic species (e.g., water with O and O, or sulfate with S and S), (2) the fractionation accompanying the removal process at any instance is described by the fractionation factor a, and (3) a does not change during the process. Under these conditions, the evolution of the isotopic composition in the residual (reactant) material is described by: formula_1 where R = ratio of the isotopes (e.g., O/O) in the reactant, R = initial ratio, X = the concentration or amount of the more abundant (lighter) isotope (e.g.,O), and X = initial concentration | https://en.wikipedia.org/wiki?curid=49301338 |
Rayleigh fractionation Because the concentration of X » Xh (heavier isotope concentration), X is approximately equal to the amount of original material in the phase. Hence, if formula_2 = fraction of material remaining, then: formula_3 For large changes in concentration, such as they occur during e.g. distillation of heavy water, these formulae need to be integrated over the distillation trajectory. For small changes such as occur during transport of water vapour through the atmosphere, the differentiated equation will usually be sufficient. | https://en.wikipedia.org/wiki?curid=49301338 |
Chemical conditioning Conditioning is a process in which reaction factors are stabilized or enhanced. It could be as increasing the quality of a material by using another material, improvement solids capture and physically and chemically water treatment or dewatering. There are three main conditioning systems: heat, inorganic chemicals and organic polymers. Conditioning increases always the efficiency of water removal. | https://en.wikipedia.org/wiki?curid=49302247 |
Ximenynic acid "Not to be confused with Ximenic acid, a 26 carbon omega-9 fatty acid." is trans-11-octadecen-9-ynoic acid, a long-chain acetylenic fatty acid. It was discovered in the fruit kernels of 3 South American ximenia species (and so named). and found to have the formula CHO. It can be extracted from the fruit kernels of the Santalum obtusifolium (Sandalwood) and the Australian sandalwood Santalum spicatum It is also found in seed oil of other plants in the Santalaceae family, including the native cherry Exocarpos cupressiformis and sweet quandong Santalum acuminatum. It was the subject of a 2003 European patent (for use in food). The patent application was deemed withdrawn in August 2012. It is used in some skincare products. | https://en.wikipedia.org/wiki?curid=49310912 |
Pressure-driven flow Pressure driven flow is a method to displace liquids in a capillary or microfluidic channel with pressure. The pressure is typically generated pneumatically by compressed air or other gases (Nitrogen, Carbon dioxide, etc) or by electrical and magnetical fields or gravitation. It is known from thermodynamics that conjugated quantities scale in a different manner. Two classes can be distinguished: intensive quantities as temperature "T", pressure "P" and amount of substance "N" or extensive quantities as entropy "S", volume "V" and chemical potential "μ". Extensive quantities scale with system size, whereas the intensive ones do not. The quantity pressure, for example, is defined as the (differential) quotient of two extensive variables: "p"=d"E"/d"V" (Energy "E" und Volume "V") and therefore scale independent as the same scaling factors appearing in the nominator as well as the denominator cancel. In microsystems the problem rises that the extremely small volumes are difficult to be controlled. The reason is the predominance of surface effects as surface charges, van-der-Waals forces and entropic effects (e.g. dewetting due to rough surfaces: the restriction in degrees of freedom of molecules penetrating such a surface is entropically more expensive than staying in bulk). Furthermore, the microsystem has to be controlled from a macroscopic human scale. | https://en.wikipedia.org/wiki?curid=49331144 |
Squire's theorem In fluid dynamics, states that of all the perturbations that may be applied to a shear flow (i.e. a velocity field of the form formula_1), the perturbations which are least stable are two-dimensional, i.e. of the form formula_2 than the three-dimensional disturbances. This applies to incompressible flows which are governed by the Navier–Stokes equations. The theorem is named after Herbert Squire, who proved the theorem in 1933. allows many simplifications to be made in stability theory. If we want to decide whether a flow is unstable or not, it suffices to look at two-dimensional perturbations. These are governed by the Orr–Sommerfeld equation for viscous flow, and by Rayleigh's equation for inviscid flow. | https://en.wikipedia.org/wiki?curid=49362816 |
Riemannian metric and Lie bracket in computational anatomy Computational anatomy (CA) is the study of shape and form in medical imaging. The study of deformable shapes in computational anatomy rely on high-dimensional diffeomorphism groups formula_1 which generate orbits of the form formula_2. In CA, this orbit is in general considered a smooth Riemannian manifold since at every point of the manifold formula_3 there is an inner product inducing the norm formula_4 on the tangent space that varies smoothly from point to point in the manifold of shapes formula_3. This is generated by viewing the group of diffeomorphisms formula_1 as a Riemannian manifold with formula_7, associated to the tangent space at formula_8 . This induces the norm and metric on the orbit formula_3 under the action from the group of diffeomorphisms | https://en.wikipedia.org/wiki?curid=49400436 |
Riemannian metric and Lie bracket in computational anatomy The diffeomorphisms in computational anatomy are generated to satisfy the Lagrangian and Eulerian specification of the flow fields, formula_10, generated via the ordinary differential equation with the Eulerian vector fields formula_11 in formula_12 for formula_13, with the inverse for the flow given by and the formula_14 Jacobian matrix for flows in formula_15 given as formula_16 To ensure smooth flows of diffeomorphisms with inverse, the vector fields formula_12 must be at least 1-time continuously differentiable in space which are modelled as elements of the Hilbert space formula_18 using the Sobolev embedding theorems so that each element formula_19 has 3-square-integrable derivatives thusly implies formula_18 embeds smoothly in 1-time continuously differentiable functions. The diffeomorphism group are flows with vector fields absolutely integrable in Sobolev norm: Shapes in Computational Anatomy (CA) are studied via the use of diffeomorphic mapping for establishing correspondences between anatomical coordinate systems. In this setting, 3-dimensional medical images are modelled as diffemorphic transformations of some exemplar, termed the template formula_21, resulting in the observed images to be elements of the random orbit model of CA. For images these are defined as formula_22, with for charts representing sub-manifolds denoted as formula_23. The orbit of shapes and forms in Computational Anatomy are generated by the group actionformula_24 | https://en.wikipedia.org/wiki?curid=49400436 |
Riemannian metric and Lie bracket in computational anatomy This is made into a Riemannian orbit by introducing a metric associated to each point and associated tangent space. For this a metric is defined on the group which induces the metric on the orbit. Take as the metric for Computational anatomy at each element of the tangent space formula_25 in the group of diffeomorphisms with the vector fields modelled to be in a Hilbert space with the norm in the Hilbert space formula_18. We model formula_28 as a reproducing kernel Hilbert space (RKHS) defined by a 1-1, differential operatorformula_29. For formula_30 a distribution or generalized function, the linear form formula_31 determines the norm:and inner product for formula_32 according to where the integral is calculated by integration by parts for formula_34 a generalized function formula_35 the dual-space. The differential operator is selected so that the Green's kernel associated to the inverse is sufficiently smooth so that the vector fields support 1-continuous derivative. The metric on the group of diffeomorphisms is defined by the distance as defined on pairs of elements in the group of diffeomorphisms according to This distance provides a right-invariant metric of diffeomorphometry, invariant to reparameterization of space since for all formula_1, The Lie bracket gives the adjustment of the velocity term resulting from a perturbation of the motion in the setting of curved spaces | https://en.wikipedia.org/wiki?curid=49400436 |
Riemannian metric and Lie bracket in computational anatomy Using Hamilton's principle of least-action derives the optimizing flows as a critical point for the action integral of the integral of the kinetic energy. The Lie bracket for vector fields in Computational Anatomy was first introduced in Miller, Trouve and Younes. The derivation calculates the perturbation formula_38 on the vector fields formula_39 in terms of the derivative in time of the group perturbation adjusted by the correction of the Lie bracket of vector fields in this function setting involving the Jacobian matrix, unlike the matrix group case: Proof: Proving Lie bracket of vector fields take a first order perturbation of the flow at point formula_1. The Lie bracket gives the first order variation of the vector field with respect to first order variation of the flow. The Euler–Lagrange equation can be used to calculate geodesic flows through the group which form the basis for the metric. The action integral for the Lagrangian of the kinetic energy for Hamilton's principle becomes The action integral in terms of the vector field corresponds to integrating the kinetic energy The shortest paths geodesic connections in the orbit are defined via Hamilton's Principle of least action requires first order variations of the solutions in the orbits of Computational Anatomy which are based on computing critical points on the metric length or energy of the path | https://en.wikipedia.org/wiki?curid=49400436 |
Riemannian metric and Lie bracket in computational anatomy The original derivation of the Euler equation associated to the geodesic flow of diffeomorphisms exploits the was a generalized function equation whenformula_43 is a distribution, or generalized function, take the first order variation of the action integral using the adjoint operator for the Lie bracket () gives for all smooth formula_44, Using the bracket formula_46 and formula_47 gives meaning for all smooth formula_48 Equation () is the Euler-equation when diffeomorphic shape momentum is a generalized function. This equation has been called EPDiff, Euler–Poincare equation for diffeomorphisms and has been studied in the context of fluid mechanics for incompressible fluids with formula_50 metric. In the random orbit model of Computational anatomy, the entire flow is reduced to the initial condition which forms the coordinates encoding the diffeomorphism, as well as providing the means of positioning information in the orbit. This was first terms a geodesic positioning system in Miller, Trouve, and Younes. From the initial condition formula_51 then geodesic positioning with respect to the Riemannian metric of Computational anatomy solves for the flow of the Euler–Lagrange equation. Solving the geodesic from the initial condition formula_51 is termed the Riemannian-exponential, a mapping formula_53 at identity to the group. The Riemannian exponential satisfies formula_54 for initial condition formula_55, vector field dynamics formula_56, It is extended to the entire group, formula_62 | https://en.wikipedia.org/wiki?curid=49400436 |
Riemannian metric and Lie bracket in computational anatomy Matching information across coordinate systems is central to computational anatomy. Adding a matching term formula_63 to the action integral of Equation () which represents the target endpoint The endpoint term adds a boundary condition for the Euler–Lagrange equation () which gives the Euler equation with boundary term. Taking the variation gives Proof:<ref>M.I. Miller, A. Trouve, L Younes, On the Metrics and Euler–Lagrange equations of Computational Anatomy, Annu. Rev. Biomed. Eng. 2002. 4:375–405 = {} &-\int_X(I \circ \varphi_1^{-1} -J) \nabla (I\circ \varphi_1^{-1}) \delta \varphi \, dx. </math> | https://en.wikipedia.org/wiki?curid=49400436 |
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