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When water vapor condenses (an equilibrium fractionation), the heavier water isotopes (HO and HO) become enriched in the liquid phase while the lighter isotopes (HO and HO) tend toward the vapor phase. | 0 | Theoretical and Fundamental Chemistry |
As a result of McCrones work on the Vinland Map, British author and researcher Ian Wilson approached McCrone in 1974 about the possibility of scientifically analyzing the Shroud of Turin, a length of linen cloth that has been venerated for centuries as the burial shroud of Jesus upon which his image is miraculously imprinted. This led to McCrones involvement with the Shroud of Turin Research Project (STURP). In 1977, a team of scientists affiliated with STURP proposed a barrage of tests to be carried out on the Shroud. With permission from the Archbishop of Turin, Cardinal Anastasio Ballestrero, STURP researchers conducted tests over a period of five days in October 1978, also using adhesive tape to obtain samples of the fibers from various parts on the Shroud's surface.
Based on his microscopic and chemical analysis of the tape samples obtained by STURP, McCrone concluded that the image on the Shroud was painted with a dilute pigment of red ochre in a collagen tempera (i.e., gelatin) medium, using a technique similar to the grisaille employed in the 14th century by Simone Martini and other European artists. McCrone also found that the "bloodstains" in the image had been highlighted with vermilion (a bright red pigment made from mercury sulfide), also in a collagen tempera medium. McCrone reported that no actual blood was present in the samples taken from the Shroud.
McCrones results were rejected by other members of STURP and McCrone resigned from STURP in June 1980. Two other members of STURP, John Heller and Alan Adler, published their own analysis concluding that Shroud did show traces of blood. Other STURP members also disputed McCrones conclusion that the Shroud image was painted, finding that physical analyses excluded the presence of pigments in sufficient quantities to account for the visible image.
McCrone continued to defend his results and to insist that polarized light microscopy, in which he was the only expert among the original members of STURP, was the correct technique to apply to the study of the Shroud. In 1983 he confidently predicted that radiocarbon dating of the Shrouds linen would show that it had been made shortly before the first historically recorded exhibition of the Shroud in 1356. The results of the 1988 radiocarbon dating of the Shroud vindicated McCrones microscopic and chemical analyses.
Until McCrones death in 2002, he continued to comment upon and explain the analysis that he had performed, becoming a prominent figure in the ongoing controversies surrounding the Shroud that attracted considerable attention in the public press. He re-stated and summarized his evidence that the Shroud was painted in an article published in 1990 in the journal Accounts of Chemical Research. He later wrote a book on the subject, Judgment Day for the Shroud of Turin, which was published in 1996 by the McCrone Research Institutes Microscope Publications and re-issued in 1999 by Prometheus Books (). In 2000, the American Chemical Society presented McCrone with its National Award in Analytical Chemistry for his work on the Shroud and for "his enduring patience for the defense of his methodologies." | 0 | Theoretical and Fundamental Chemistry |
The number and organization of operons has been studied most critically in E. coli. As a result, predictions can be made based on an organism's genomic sequence.
One prediction method uses the intergenic distance between reading frames as a primary predictor of the number of operons in the genome. The separation merely changes the frame and guarantees that the read through is efficient. Longer stretches exist where operons start and stop, often up to 40–50 bases.
An alternative method to predict operons is based on finding gene clusters where gene order and orientation is conserved in two or more genomes.
Operon prediction is even more accurate if the functional class of the molecules is considered. Bacteria have clustered their reading frames into units, sequestered by co-involvement in protein complexes, common pathways, or shared substrates and transporters. Thus, accurate prediction would involve all of these data, a difficult task indeed.
Pascale Cossarts laboratory was the first to experimentally identify all operons of a microorganism, Listeria monocytogenes. The 517 polycistronic operons are listed in a 2009 study describing the global changes in transcription that occur in L. monocytogenes' under different conditions. | 1 | Applied and Interdisciplinary Chemistry |
Parasite Rex: Inside the Bizarre World of Natures Most Dangerous Creatures is a nonfiction book by Carl Zimmer that was published by Free Press in 2000. The book discusses the history of parasites on Earth and how the field and study of parasitology formed, along with a look at the most dangerous parasites ever found in nature. A special paperback edition was released in March 2011 for the tenth anniversary of the books publishing, including a new epilogue written by Zimmer. Signed bookplates were also given to fans that sent in a photo of themselves with a copy of the special edition.
The cover of Parasite Rex includes a scanning electron microscope image of a tick as the focus, along with illustrations in the centerfold of parasites and topics discussed in the book. | 1 | Applied and Interdisciplinary Chemistry |
Being smaller than the wavelengths of visible light, nanoparticles can be dispersed in transparent media without affecting its transparency at those wavelengths. This property is exploited in many applications, such as photocatalysis. | 0 | Theoretical and Fundamental Chemistry |
Bacteria utilize complex long helical proteins as chemoreceptors, permitting signals to travel long distances across the cell's membrane. Chemoreceptors allow bacteria to react to chemical stimuli in their environment and regulate their movement accordingly. In archaea, transmembrane receptors comprise only 57% of chemoreceptors, while in bacteria the percentage rises to 87%. This is an indicator that chemoreceptors play a heightened role in the sensing of cytosolic signals in archaea. | 0 | Theoretical and Fundamental Chemistry |
The Wolf effect (sometimes Wolf shift) is a frequency shift in the electromagnetic spectrum.
The phenomenon occurs in several closely related phenomena in radiation physics, with analogous effects occurring in the scattering of light. It was first predicted by Emil Wolf in 1987 and subsequently confirmed in the laboratory in acoustic sources by Mark F. Bocko, David H. Douglass, and Robert S. Knox, and a year later in optic sources by Dean Faklis and George Morris in 1988. | 0 | Theoretical and Fundamental Chemistry |
The classical Taylor–Couette flow problem assumes infinitely long cylinders; if the cylinders have non-negligible finite length , then the analysis must be modified (though the flow is still unidirectional). For , the finite-length problem can be solved using separation of variables or integral transforms, giving:
where are the Modified Bessel functions of the first and second kind. | 1 | Applied and Interdisciplinary Chemistry |
* 1900, Elliott Cresson Medal, The Franklin Institute Awards, Philadelphia, PA, USA
* 1901, raised to the hereditary nobility by Franz Joseph I of Austria, with the title of Freiherr Auer von Welsbach
*1920, Werner von Siemens Ring
*1921, Wilhelm Exner Medal, inaugural awardee, Austrian Industry Association, Austria
* 1988, the Welsbach Museum at Althofen was opened in April, 1998
* 2011, National Inventors Hall of Fame, North Canton, Ohio, USA | 1 | Applied and Interdisciplinary Chemistry |
The transmission of sound can be illustrated by using a model consisting of an array of spherical objects interconnected by springs.
In real material terms, the spheres represent the materials molecules and the springs represent the bonds between them. Sound passes through the system by compressing and expanding the springs, transmitting the acoustic energy to neighboring spheres. This helps transmit the energy in-turn to the neighboring spheres springs (bonds), and so on.
The speed of sound through the model depends on the stiffness/rigidity of the springs, and the mass of the spheres. As long as the spacing of the spheres remains constant, stiffer springs/bonds transmit energy more quickly, while more massive spheres transmit energy more slowly.
In a real material, the stiffness of the springs is known as the "elastic modulus", and the mass corresponds to the material density. Sound will travel more slowly in spongy materials and faster in stiffer ones. Effects like dispersion and reflection can also be understood using this model.
For instance, sound will travel 1.59 times faster in nickel than in bronze, due to the greater stiffness of nickel at about the same density. Similarly, sound travels about 1.41 times faster in light hydrogen (protium) gas than in heavy hydrogen (deuterium) gas, since deuterium has similar properties but twice the density. At the same time, "compression-type" sound will travel faster in solids than in liquids, and faster in liquids than in gases, because the solids are more difficult to compress than liquids, while liquids, in turn, are more difficult to compress than gases.
Some textbooks mistakenly state that the speed of sound increases with density. This notion is illustrated by presenting data for three materials, such as air, water, and steel and noting that the speed of sound is higher in the denser materials. But the example fails to take into account that the materials have vastly different compressibility, which more than makes up for the differences in density, which would slow wave speeds in the denser materials. An illustrative example of the two effects is that sound travels only 4.3 times faster in water than air, despite enormous differences in compressibility of the two media. The reason is that the greater density of water, which works to slow sound in water relative to the air, nearly makes up for the compressibility differences in the two media.
A practical example can be observed in Edinburgh when the "One oClock Gun" is fired at the eastern end of Edinburgh Castle. Standing at the base of the western end of the Castle Rock, the sound of the Gun can be heard through the rock, slightly before it arrives by the air route, partly delayed by the slightly longer route. It is particularly effective if a multi-gun salute such as for "The Queens Birthday" is being fired. | 1 | Applied and Interdisciplinary Chemistry |
The hydrogen bond can be compared with the closely related dihydrogen bond, which is also an intermolecular bonding interaction involving hydrogen atoms. These structures have been known for some time, and well characterized by crystallography; however, an understanding of their relationship to the conventional hydrogen bond, ionic bond, and covalent bond remains unclear. Generally, the hydrogen bond is characterized by a proton acceptor that is a lone pair of electrons in nonmetallic atoms (most notably in the nitrogen, and chalcogen groups). In some cases, these proton acceptors may be pi-bonds or metal complexes. In the dihydrogen bond, however, a metal hydride serves as a proton acceptor, thus forming a hydrogen-hydrogen interaction. Neutron diffraction has shown that the molecular geometry of these complexes is similar to hydrogen bonds, in that the bond length is very adaptable to the metal complex/hydrogen donor system. | 0 | Theoretical and Fundamental Chemistry |
According to the Alternative Fluorocarbons Environmental Acceptability Study (AFEAS), in 2006 global production (excluding India and China who did not report production data) of HCFC-142b was 33,779 metric tons and an increase in production from 2006 to 2007 of 34%.
For the most part, concentrations of HCFCs in the atmosphere match the emission rates that were reported by industries. The exception to this is HCFC-142b which had a higher concentration than the emission rates suggest it should. | 1 | Applied and Interdisciplinary Chemistry |
Columnar structures arise naturally in the context of dense hard sphere packings inside a cylinder. Mughal et al. studied such packings using simulated annealing up to the diameter ratio of for cylinder diameter to sphere diameter . This includes some structures with internal spheres that are not in contact with the cylinder wall.
They calculated the packing fraction for all these structures as a function of the diameter ratio. At the peaks of this curve lie the uniform structures. In-between these discrete diameter ratios are the line slips at a lower packing density. Their packing fraction is significantly smaller than that of an unconfined lattice packing such as fcc, bcc, or hcp due to the free volume left by the cylindrical confinement.
The rich variety of such ordered structures can also be obtained by sequential depositioning the spheres into the cylinder. Chan reproduced all dense sphere packings up to using an algorithm, in which the spheres are placed sequentially dropped inside the cylinder.
Mughal et al. also discovered that such structures can be related to disk packings on a surface of a cylinder. The contact network of both packings are identical. For both packing types, it was found that different uniform structures are connected with each other by line slips.
Fu et al. extended this work to higher diameter ratios using linear programming and discovered 17 new dense structures with internal spheres that are not in contact with the cylinder wall.
A similar variety of dense crystalline structures have also been discovered for columnar packings of spheroids through Monte Carlo simulations. Such packings include achiral structures with specific spheroid orientations and chiral helical structures with rotating spheroid orientations. | 0 | Theoretical and Fundamental Chemistry |
Typical examples of an inflatable include the inflatable movie screen, inflatable boat, the balloon, the airship, evacuation slide, furniture, kites, and numerous air-filled swimming pool toys. Air beams as structural elements are finding increasing applications.
Smaller-scale inflatables (such as pool toys) generally consist of one or more "air chambers", which are hollow enclosures bound by a soft and flexible airtight material (such as vinyl), which a gas can enter into or leave from through valves (usually one on each air chamber). The design dependence upon an enclosed pocket of gas leads to a need for a very durable surface material and/or ease of repair of tears and holes on the material, since a puncture or tear will result in the escape of the gas inside (a leak) and the deflation of the inflatable, which depends on the gas's pressure to hold its form. Detectable leaks can be caused by holes (from punctures or tears) on the material, the separating of seams, the separating of valve parts, or an improperly shut or improperly closing valve. Even if an inflatable possesses no macroscopic leaks, the gas inside will usually diffuse out of the inflatable, albeit at a much slower rate, until equilibrium is reached with the pressure outside the inflatable.
Many inflatables are made of material that does not stretch upon inflation; a notable exception of this is the balloon, whose rubber stretches greatly when inflated.
The airship is usually inflated with helium as it is lighter than air and does not burn unlike hydrogen airships such as the Hindenburg.
Inflatables are also used for the construction of specific sports pitches, military quick-assembly tents, camping tent air beams, and noise makers. Inflatable aircraft including the Goodyear Inflatoplane have been used. Inflation by dynamic ram-air is providing wings for hang gliding and paragliding.
Inflatables came very much into the public eye as architectural and domestic objects when synthetic materials became commonplace. Iconic structures like the US Pavilion at the 1970 Osaka Expo by Davis and Brody and Victor Lundy's travelling pavilion for the Atomic Energy Commission popularized the idea that inflatables can be a way to build large structures with very extendend interior spans without pillars. These great hopes for inflatable structures would later be dashed by the many practical difficulties faced by inflatable buildings, such as climatization, safety, sensitivity to wind and fireproofing that, currently, restrict their use to very specific circumstances.
The DVD Ant Farm has directions for making your own inflatables, using plastic bags and an iron. The low technological barrier to building inflatables is further lowered by DIY instruction sets like the Inflatocookbook.
A patent was granted in Australia in 2001 for a "Manually portable and inflatable automobile" (Australian Patent Number 2001100029), however no known practical form of this type of inflatable has yet been commercialised.
Large scale low-pressure inflatables are often seen at festivals as decorations or inflatable games. These are made out of rip stop nylon and have a constant flow of air from a blower inflating them.
In some cases, an inflatable roof is added to an otherwise traditional structure: the biggest example in the world was the BC Place Stadium in Vancouver, British Columbia. Another example can be found in the Roman amphitheater of Nîmes.
Many companies use inflatables in the shape of their product or service; they do this because no permission is needed to display them from a local council or authority and they are easily moved from place to place.
Inflatables have been used prominently in works of art by artists such as Paul Chan (artist), Martin Creed, John Jasperse, Jeff Koons, and Andy Warhol. | 1 | Applied and Interdisciplinary Chemistry |
Woodward also received over twenty honorary degrees, including honorary doctorates from the following universities:
* Wesleyan University in 1945;
* Harvard University in 1957;
* University of Cambridge in 1964;
* Brandeis University in 1965;
* Technion Israel Institute of Technology in Haifa in 1966;
* University of Western Ontario in Canada in 1968;
* University of Louvain in Belgium, 1970. | 0 | Theoretical and Fundamental Chemistry |
In occupational safety and health, biomonitoring may be done for reasons of regulatory compliance, workplace health surveillance and research, confirming effectiveness of hazard controls, or as a component of occupational risk assessment. It can also be used to reconstruct exposures following acute or accidental events, and to assess the effectiveness of personal protective equipment. It is useful for dermal exposures, for which sampling methods are often not readily available, and for finding unexpected exposures or routes. There are also biomarkers not just for chemical hazards, but also other types such as noise and stress. Occupational health differs from environmental health in that the former has smaller number of exposed individuals, but with a wider range of exposure levels.
Biomonitoring is complementary to exposure monitoring in that it measures the internal dose of a toxicant within the body rather than its concentration outside the body, with the advantage that it confirms whether not only exposure but uptake has actually occurred. It also takes into account differences in metabolism, physical exertion, and mixtures of toxicants between individuals that affect the internal dose. It can be done in an individual or collective manner.
A major use of occupational toxicology data is for determining what biomarkers (including both the a toxicant and its metabolites) may be used for biomonitoring, and establishing biological exposure indices. These are used during exposure assessment and workplace health surveillance activities to identify overexposure, and to test the validity of occupational exposure limits. These biomarkers are intended to aid in prevention by identifying early adverse affects, unlike diagnostics for clinical medicine that are designed to reveal advanced pathologic states.
In the United States, the Occupational Safety and Health Administration as of 2017 has three regulations that require biomonitoring: after exposure to benzene in an unplanned release, and for employees exposed to cadmium or lead at or above a specified level over a specified amount of time. In the European Union, biological limit values are health-based, while biological guidance values are statistically derived and indicate background exposures in the general population. As of 2020 lead is the only substance that has a binding biological limit value in the EU. Voluntary lists of biological exposure limits or action levels are maintained by the American Conference of Governmental Industrial Hygienists, German Research Foundation, UK Health and Safety Executive, France's ANSES, and the Swiss Accident Insurance Fund. Biomonitoring for research purposes is performed by the U.S. National Institute for Occupational Safety and Health as part of its Adult Blood Lead Epidemiology and Surveillance program, as well as other occupational health studies. | 1 | Applied and Interdisciplinary Chemistry |
Burning of the most abundant isotope of lithium, lithium-7, occurs by a collision of Li and a proton producing beryllium-8, which promptly decays into two helium-4 nuclei. The temperature necessary for this reaction is just below the temperature necessary for hydrogen fusion. Convection in low-mass stars ensures that lithium in the whole volume of the star is depleted. Therefore, the presence of the lithium line in a candidate brown dwarf's spectrum is a strong indicator that it is indeed substellar. | 0 | Theoretical and Fundamental Chemistry |
The first form of crucible steel was wootz, developed in India some time around 300 BCE. In its production the iron was mixed with glass and then slowly heated and then cooled. As the mixture cooled the glass would bond to impurities in the steel and then float to the surface, leaving the steel considerably purer. Carbon could enter the iron by diffusing in through the porous walls of the crucibles. Carbon dioxide would not react with the iron, but the small amounts of carbon monoxide could, adding carbon to the mix with some level of control. Wootz was widely exported throughout the Middle East, where it was combined with a local production technique around 1000 CE to produce Damascus steel, famed throughout the world. Wootz derives from the Tamil term for steel urukku. Indian wootz steel was the first high quality steel that was produced.
Henry Yule quoted the 12th-century Arab Edrizi who wrote: "The South Indians excel in the manufacture of iron, and in the preparations of those ingredients along with which it is fused to obtain that kind of soft iron which is usually styled Indian steel. They also have workshops wherein are forged the most famous sabres in the world. ...It is not possible to find anything to surpass the edge that you get from Indian steel (al-hadid al-Hindi).
As early as the 17th century, Europeans knew of India's ability to make crucible steel from reports brought back by travelers who had observed the process at several places in southern India. Several attempts were made to import the process, but failed because the exact technique remained a mystery. Studies of wootz were made in an attempt to understand its secrets, including a major effort by the famous scientist, Michael Faraday, son of a blacksmith. Working with a local cutlery manufacturer he wrongly concluded that it was the addition of aluminium oxide and silica from the glass that gave wootz its unique properties.
After the Indian Rebellion of 1857, many Indian wootz steel swords were ordered to be destroyed by the East India Company. The metalworking industry in India went into decline during the period of British Crown control due to various colonial policies, but steel production was revived in India by Jamsetji Tata. | 1 | Applied and Interdisciplinary Chemistry |
A formerly unknown derivative of palytoxin, ovatoxin-a, produced as a marine aerosol by the tropical dinoflagellate Ostreopsis ovata caused hundreds of people in Genoa, Italy, to fall ill. In 2005 and 2006 blooms of these algae occurred in the Mediterranean sea. All those affected needed hospitalization. Symptoms were high fever, coughs and wheezes. | 0 | Theoretical and Fundamental Chemistry |
Diebold's first appointment after graduation was as a post-doctoral research associate in the group of Theodore E. Madey in the department of physics at Rutgers University (1990-1993). It was there that she was first introduced to oxide surfaces, an area that she would later come to refer to as "the love of her scientific life". Her first faculty appointment followed, at Tulane University, New Orleans, USA, where she was an assistant professor (1993–1999), associate professor (1999–2001), and professor of physics (2001–2009), and also an adjunct professor of chemistry (1993–2009). During this time period, she also completed her habilitation in experimental physics (TU Vienna, 1998), held the Yahoo! Founder Chair in Science and Engineering (2006–2009), and was the associate department chair (2002–2009).
In 2005, Diebold and her group were forced to temporarily evacuate from New Orleans, which experienced massive flooding and power outages from the impact of Hurricane Katrina. They were hosted by the group of Theodore E. Madey at Rutgers University during this challenging period.
In 2010 she moved to the Institute of Applied Physics at TU Wien where she is currently a professor of surface science and deputy department head, and retains the title of research professor at Tulane University.. Since 2022 she also serves as Vice President of the Austrian Academy of Sciences. | 0 | Theoretical and Fundamental Chemistry |
Calthemite is a secondary deposit, derived from concrete, lime, mortar or other calcareous material outside the cave environment. Calthemites grow on or under, man-made structures and mimic the shapes and forms of cave speleothems, such as stalactites, stalagmites, flowstone etc. Calthemite is derived from the Latin calx (genitive calcis) "lime" + Latin < Greek théma, "deposit" meaning ‘something laid down’, (also Mediaeval Latin thema, "deposit") and the Latin –ita < Greek -itēs – used as a suffix indicating a mineral or rock. The term "speleothem", due to its definition (spēlaion "cave" + théma "deposit" in ancient Greek) can only be used to describe secondary deposits in caves and does not include secondary deposits outside the cave environment. | 1 | Applied and Interdisciplinary Chemistry |
The Danheiser benzannulation is a chemical reaction used in organic chemistry to generate highly substituted phenols in a single step. It is named after Rick L. Danheiser who developed the reaction. | 0 | Theoretical and Fundamental Chemistry |
Drinking water which has been chlorinated to kill microbes may contain trace levels of chlorine. The World Health Organization recommends an upper limit of 5 ppm.
Although low, 5 ppm is enough to slowly attack certain types of plastic, particularly when the water is heated, as it is for washing.
Polyethylene, polybutylene and acetal resin (polyoxymethylene) pipework and fittings are all susceptible. Attack leads to hardening of pipework, which can leave it brittle and more susceptible to mechanical failure. | 0 | Theoretical and Fundamental Chemistry |
The corium undergoes degradation. The Elephants Foot, hard and strong shortly after its formation, is now cracked enough that a cotton ball treated with glue can easily remove its top 1- to 2-centimeter layer. The structures shape itself is changed as the material slides down and settles. The corium temperature is now just slightly different from ambient. The material is therefore subject to both day–night temperature cycling and weathering by water. The heterogeneous nature of corium and different thermal expansion coefficients of the components causes material deterioration with thermal cycling. Large amounts of residual stresses were introduced during solidification due to the uncontrolled cooling rate. The water, seeping into pores and microcracks, has frozen there. This is the same process that creates potholes on roads, accelerates cracking.
Corium (and also highly irradiated uranium fuel) has the property of spontaneous dust generation, or spontaneous self-sputtering of the surface. The alpha decay of isotopes inside the glassy structure causes Coulomb explosions, degrading the material and releasing submicron particles from its surface. The level of radioactivity is such that during 100 years, the lavas self irradiation ( α decays per gram and 2 to of β or γ) will fall short of the level required to greatly change the properties of glass (10 α decays per gram and 10 to 10 Gy of β or γ). Also the lavas rate of dissolution in water is very low (10 g·cm·day), suggesting that the lava is unlikely to dissolve in water.
It is unclear how long the ceramic form will retard the release of radioactivity. From 1997 to 2002, a series of papers were published that suggested that the self irradiation of the lava would convert all 1,200 tons into a submicrometre and mobile powder within a few weeks. But it has been reported that it is likely that the degradation of the lava is to be a slow and gradual process rather than a sudden rapid process. The same paper states that the loss of uranium from the wrecked reactor is only per year. This low rate of uranium leaching suggests that the lava is resisting its environment. The paper also states that when the shelter is improved, the leaching rate of the lava will decrease.
Some of the surfaces of the lava flows have started to show new uranium minerals such as UO·2HO (eliantinite), (UO)O·4HO (studtite), uranyl carbonate (rutherfordine), čejkaite (), and the unnamed compound NaU(CO)·2HO. These are soluble in water, allowing mobilization and transport of uranium. They look like whitish yellow patches on the surface of the solidified corium. These secondary minerals show several hundred times lower concentration of plutonium and several times higher concentration of uranium than the lava itself. | 0 | Theoretical and Fundamental Chemistry |
Transduction was discovered in Salmonella by Norton Zinder and Joshua Lederberg at the University of Wisconsin–Madison in 1952. | 1 | Applied and Interdisciplinary Chemistry |
Chromatin remodeling plays a central role in the regulation of gene expression by providing the transcription machinery with dynamic access to an otherwise tightly packaged genome. Further, nucleosome movement by chromatin remodelers is essential to several important biological processes, including chromosome assembly and segregation, DNA replication and repair, embryonic development and pluripotency, and cell-cycle progression. Deregulation of chromatin remodeling causes loss of transcriptional regulation at these critical check-points required for proper cellular functions, and thus causes various disease syndromes, including cancer. | 1 | Applied and Interdisciplinary Chemistry |
An excess heat observation is based on an energy balance. Various sources of energy input and output are continuously measured. Under normal conditions, the energy input can be matched to the energy output to within experimental error. In experiments such as those run by Fleischmann and Pons, an electrolysis cell operating steadily at one temperature transitions to operating at a higher temperature with no increase in applied current. If the higher temperatures were real, and not an experimental artifact, the energy balance would show an unaccounted term. In the Fleischmann and Pons experiments, the rate of inferred excess heat generation was in the range of 10–20% of total input, though this could not be reliably replicated by most researchers. Researcher Nathan Lewis discovered that the excess heat in Fleischmann and Ponss original paper was not measured, but estimated from measurements that didnt have any excess heat.
Unable to produce excess heat or neutrons, and with positive experiments being plagued by errors and giving disparate results, most researchers declared that heat production was not a real effect and ceased working on the experiments. In 1993, after their original report, Fleischmann reported "heat-after-death" experiments—where excess heat was measured after the electric current supplied to the electrolytic cell was turned off. This type of report has also become part of subsequent cold fusion claims. | 0 | Theoretical and Fundamental Chemistry |
Negative thermal expansion is usually observed in non-close-packed systems with directional interactions (e.g. ice, graphene, etc.) and complex compounds (e.g. , , beta-quartz, some zeolites, etc.). However, in a paper, it was shown that negative thermal expansion (NTE) is also realized in single-component close-packed lattices with pair central force interactions. The following sufficient condition for potential giving rise to NTE behavior is proposed for the interatomic potential, , at the equilibrium distance :
where is shorthand for the third derivative of the interatomic potential at the equilibrium point:
This condition is (i) necessary and sufficient in 1D and (ii) sufficient, but not necessary in 2D and 3D. An approximate necessary and sufficient condition is derived in a paper
where is the space dimensionality. Thus in 2D and 3D negative thermal expansion in close-packed systems with pair interactions is realized even when the third derivative of the potential is zero or even negative. Note that one-dimensional and multidimensional cases are qualitatively different. In 1D thermal expansion is caused by anharmonicity of interatomic potential only. Therefore, the sign of thermal expansion coefficient is determined by the sign of the third derivative of the potential. In multidimensional case the geometrical nonlinearity is also present, i.e. lattice vibrations are nonlinear even in the case of harmonic interatomic potential. This nonlinearity contributes to thermal expansion. Therefore, in multidimensional case both and are present in the condition for negative thermal expansion. | 0 | Theoretical and Fundamental Chemistry |
As shown in Scheme 7, Ojima lactam 7.1 reacted with alcohol 7.2 with sodium bis(trimethylsilyl)amide as a base. This alcohol is the triethylsilyl ether of the naturally occurring compound baccatin III. The related compound, 10-deacetylbaccatin III, is found in Taxus baccata, also known as the European Yew, in concentrations of 1 gram per kilogram leaves. Removal of the triethylsilyl protecting group gave Taxol. | 0 | Theoretical and Fundamental Chemistry |
STAT6-mediated signaling pathway is required for the development of T-helper type 2 (Th2) cells and Th2 immune response. Expression of Th2 cytokines, including IL-4, IL-13, and IL-5, was reduced in STAT6-deficient mice. STAT 6 protein is crucial in IL4 mediated biological responses. It was found that STAT6 induce the expression of BCL2L1/BCL-X(L), which is responsible for the anti-apoptotic activity of IL4. IL-4 stimulates the phosphorylation of IL-4 receptor, which recruits cytosolic STAT6 by its SH2 domain and STAT6 is phosphorylated on tyrosine 641 (Y641) by JAK1, which results in the dimerization and nuclear translocation of STAT6 to activate target genes. Knockout studies in mice suggested the roles of this gene in differentiation of T helper 2 (Th2), expression of cell surface markers, and class switch of immunoglobulins.
Activation of STAT6 signaling pathway is necessary in macrophage function, and is required for the M2 subtype activation of macrophages. STAT6 protein also regulates other transcription factor as Gata3, which is important regulator of Th2 differentiation. STAT6 is also required for the development of IL-9-secreting T cells.
STAT6 also plays a critical role in Th2 lung inflammatory responses including clearance of parasitic infections and in the pathogenesis of asthma. Th2-cell derived cytokines as IL-4 and IL-13 induce the production of IgE which is a major mediator in allergic response. Association studies searching for relation of polymorphisms in STAT6 with IgE level or asthma discovered a few polymorphisms significantly associated with examined traits. Only two polymorphisms showed repeatedly significant clinical association and/or functional effect on STAT6 function (GT repeats in exon 1 and rs324011 polymorphism in intron 2). | 1 | Applied and Interdisciplinary Chemistry |
This formula must not be confused with the Fanning equation, using the Fanning friction factor , equal to one fourth the Darcy-Weisbach friction factor . Here the pressure drop is: | 1 | Applied and Interdisciplinary Chemistry |
A water supply network or water supply system is a system of engineered hydrologic and hydraulic components that provide water supply. A water supply system typically includes the following:
# A drainage basin (see water purification – sources of drinking water)
# A raw water collection point (above or below ground) where the water accumulates, such as a lake, a river, or groundwater from an underground aquifer. Raw water may be transferred using uncovered ground-level aqueducts, covered tunnels, or underground water pipes to water purification facilities.
# Water purification facilities. Treated water is transferred using water pipes (usually underground).
# Water storage facilities such as reservoirs, water tanks, or water towers. Smaller water systems may store the water in cisterns or pressure vessels. Tall buildings may also need to store water locally in pressure vessels in order for the water to reach the upper floors.
# Additional water pressurizing components such as pumping stations may need to be situated at the outlet of underground or aboveground reservoirs or cisterns (if gravity flow is impractical).
# A pipe network for distribution of water to consumers (which may be private houses or industrial, commercial, or institution establishments) and other usage points (such as fire hydrants)
# Connections to the sewers (underground pipes, or aboveground ditches in some developing countries) are generally found downstream of the water consumers, but the sewer system is considered to be a separate system, rather than part of the water supply system.
Water supply networks are often run by public utilities of the water industry. | 1 | Applied and Interdisciplinary Chemistry |
Medium-chain acyl-coenzyme A dehydrogenase (MCAD) deficiency is the most common fatty acid β-oxidation disorder and a prevalent metabolic congenital error It is often identified through newborn screening. Although children are normal at birth, symptoms usually emerge between three months and two years of age, with some cases appearing in adulthood.
Medium-chain acyl-CoA dehydrogenase (MCAD) plays a crucial role in mitochondrial fatty acid β-oxidation, a process vital for generating energy during extended fasting or high-energy demand periods. This process, especially important when liver glycogen is depleted, supports hepatic ketogenesis. The specific step catalyzed by MCAD involves the dehydrogenation of acyl-CoA. This step converts medium-chain acyl-CoA to trans-2-enoyl-CoA, which is then further metabolized to produce energy in the form of ATP.
* Affected children, who seem healthy initially, may experience symptoms like low blood sugar without ketones (hypoketotic hypoglycemia) and vomiting
* Can escalate to lethargy, seizures and coma, typically triggered by illness
* Acute episodes may also involve enlarged liver (hepatomegaly) and liver issues
* Sudden death
* Administering simple carbohydrates
* Avoiding fasting
* Frequent feedings for infants
* For toddlers, a diet with less than 30% of total energy from fat
* Administering 2 g/kg of uncooked cornstarch at bedtime for sufficient overnight glucose
* Preventing hypoglycemia, especially due to excessive fasting.
* Avoiding infant formulas with medium-chain triglycerides as the main fat source | 1 | Applied and Interdisciplinary Chemistry |
The DNA of interest needs to be fragmented to provide a relevant DNA segment of suitable size. Preparation of DNA fragments for cloning is achieved by means of PCR, but it may also be accomplished by restriction enzyme digestion and fractionation by gel electrophoresis. | 1 | Applied and Interdisciplinary Chemistry |
A sperm donor will usually be required to enter into a contract with a sperm bank to supply their semen, typically for a period of six to twenty-four months depending on the number of pregnancies which the sperm bank intends to produce from the donor. If a sperm bank has access to world markets e.g. by direct sales, or sales to clinics outside their own jurisdiction, a man may donate for a longer period than two years, as the risk of consanguinity is reduced (although local laws vary widely). Some sperm banks with access to world markets impose their own rules on the number of pregnancies which can be achieved in a given regional area or a state or country, and these sperm banks may permit donors to donate for four or five years, or even longer.
The contract may also specify the place and hours for donation, a requirement to notify the sperm bank in the case of acquiring a sexual infection, and the requirement not to have intercourse or to masturbate for a period of usually 2–3 days before making a donation.
The contract may also describe the types of treatment for which the donated sperm may be used, such as artificial insemination and IVF, and whether the donors sperm may be used in surrogacy arrangements. It may also stipulate whether the sperm may be used for research or training purposes. In certain cases, a sperm donor may specify the maximum number of offspring or families which may be produced from the donors sperm. Family may be defined as a couple who may each bear children from the same donor. The contract may also require consent if the donor's samples are to be exported. In the United Kingdom, for example, the maximum number of families for which a donor is permitted to bear children is ten, but a sperm bank or fertility center in the UK may export sperm to other fertility centers so that this may be used to produce more pregnancies abroad. Where this happens, consent must be provided by the donor. Faced with a growing demand for donor sperm, sperm banks may try to maximize the use of a donor whilst still reducing the risk of consanguinity. In legislations with a national register of sperm donors or a national regulatory body, a sperm donor may be required to fill in a separate form of consent which will be registered with the regulatory authority. In the United Kingdom this body is the HFEA.
A sperm donor generally produces and collects sperm at a sperm bank or clinic by masturbation in a private room or cabin, known as a mens production room (UK), donor cabin' (DK) or a masturbatorium (US). Many of these facilities contain pornography such as videos/DVD, magazines, and/or photographs which may assist the donor in becoming aroused in order to facilitate production of the ejaculate, also known as the "semen sample" but the increasing usage of porn in the U.S. has dulled many men to its effects. Often, using any type of personal lubricant, saliva, oil or anything else to lubricate and stimulate the genitals is prohibited as it can contaminate the semen sample and have negative impacts on the quality and health of sperm. In some circumstances, it may also be possible for semen from donors to be collected during sexual intercourse with the use of a collection condom which results in higher sperm counts. | 1 | Applied and Interdisciplinary Chemistry |
After postdoctoral fellowships at the ETH, Zürich with Albert Eschenmoser, funded by a Royal Society-Swiss National Foundation Fellowship, and at the University of Cambridge with Jack Lewis, he was appointed to a senior demonstratorship at the University of Edinburgh in 1982. He was subsequently promoted to lecturer, reader and then professor, and in 1995 was appointed to the University of Nottingham as head and professor of inorganic chemistry. He served as head of the School of Chemistry at the University of Nottingham from 1999 to 2005, and as executive dean of the Faculty of Science (2011–2015). In 2015 he moved to his current position as vice-president and dean of the Faculty of Science and Engineering and professor of chemistry at the University of Manchester.
He has been a visiting professor at the University of Toronto, Canada, the University of Otago, Dunedin, New Zealand and the Université Louis Pasteur, Strasbourg, France, and has published over 540 publications and patents.
His early independent research focussed on the chemistry of transition metal thioether and aza macrocyclic complexes with particular focus on the stabilisation of unusual oxidation state species. This work led to the isolation and characterisation of unique mononuclear M(I)/(III) (M = Ni, Pd, Pt) and M(II) (M = Ag, Au, Rh, Ir) complexes. His current research focuses on the development of new advanced functional materials, particularly metal-organic framework materials for selective fuel and toxic gas capture, purification and catalysis. | 0 | Theoretical and Fundamental Chemistry |
Generally, the Fischer–Tropsch process is operated in the temperature range of . Higher temperatures lead to faster reactions and higher conversion rates but also tend to favor methane production. For this reason, the temperature is usually maintained at the low to middle part of the range. Increasing the pressure leads to higher conversion rates and also favors the formation of long-chained alkanes, both of which are desirable. Typical pressures range from one to several tens of atmospheres. Even higher pressures would be favorable, but the benefits may not justify the additional costs of high-pressure equipment, and higher pressures can lead to catalyst deactivation via coke formation.
A variety of synthesis-gas compositions can be used. For cobalt-based catalysts the optimal H:CO ratio is around 1.8–2.1. Iron-based catalysts can tolerate lower ratios, due to the intrinsic water-gas shift reaction activity of the iron catalyst. This reactivity can be important for synthesis gas derived from coal or biomass, which tend to have relatively low H:CO ratios (< 1). | 0 | Theoretical and Fundamental Chemistry |
Thalidomide and its immune-modulating analogs alter the production of the inflammatory cytokines TNF-α, IL-1, IL-6, IL-12 and anti-inflammatory cytokine IL-10. The analogs are believed to inhibit the production of TNF-α, where the analogs are up to 50.000 times more potent in vitro than the parent drug thalidomide. The mechanism is believed to be through enhanced degradation of TNF-α mRNA, resulting in diminished amounts of this pro-inflammatory cytokine secreted. This explains the effect of thalidomide when given to ENL patients, as they commonly have high levels of TNF-α in their blood and in dermatological lesions. In contrast, in vitro assay demonstrated that TNF-α is actually enhanced in T-cell activation, where CD4+ and CD8+ T lymphocytes were stimulated by anti-CD3 which was later confirmed in an early phase trials involving solid tumors and inflammatory dermatologic diseases.
IL-12 is another cytokine both suppressed and enhanced by thalidomide and its analogs. When monocytes are stimulated by lipopolysaccharides, IL-12 production is suppressed but during T-cell stimulation the production is enhanced.
Lenalidomide is believed to be about 1000 times more potent in vitro than thalidomide in anti-inflammatory properties and pomalidomide about 10 times more potent than lenalidomide. It is worth noticing however that, when comparing lenalidomide and pomalidomide, clinical relevance of higher in vitro potency is unclear since maximum tolerated dose of pomalidomide is 2 mg daily compared to 25 mg for lenalidomide, leading to 10-100 times lower plasma drug concentration of pomalidomide. | 1 | Applied and Interdisciplinary Chemistry |
Resonant panels, Helmholtz resonators and other resonant absorbers work by damping a sound wave as they reflect it. Unlike porous absorbers, resonant absorbers are most effective at low-medium frequencies and the absorption of resonant absorbers is matched to a narrow frequency range. | 1 | Applied and Interdisciplinary Chemistry |
The development of various methods of cryopreservation of bovine embryos improved embryo transfer technique considerably efficient technology, no longer depending on the immediate readiness of suitable recipients. Pregnancy rates are just slightly less than those achieved with fresh embryos. Recently, the use of cryoprotectants such as ethylene glycol has permitted the direct transfer of bovine embryos. The world's first live crossbred bovine calf produced under tropical conditions by Direct Transfer (DT) of embryo frozen in ethylene glycol freeze media was born on 23 June 1996. Dr. Binoy Sebastian Vettical of Kerala Livestock Development Board Ltd has produced the embryo stored frozen in Ethylene Glycol freeze media by slow programmable freezing (SPF) technique and transferred directly to recipient cattle immediately after thawing the frozen straw in water for the birth of this calf. In a study, in vivo produced crossbred bovine embryos stored frozen in ethylene glycol freeze media were transferred directly to recipients under tropical conditions and achieved a pregnancy rate of 50 percent. In a survey of the North American embryo transfer industry, embryo transfer success rates from direct transfer of embryos were as good as to those achieved with glycerol. Moreover, in 2011, more than 95% of frozen-thawed embryos were transferred by Direct Transfer. | 1 | Applied and Interdisciplinary Chemistry |
The settling particles can contact each other and arise when approaching the floor of the sedimentation tanks at very high particle concentration. So that further settling will only occur in adjust matrix as the sedimentation rate decreasing. This is can be illustrated by the lower region of the zone-settling diagram (Figure 3). In Compression zone, the settled solids are compressed by gravity (the weight of solids), as the settled solids are compressed under the weight of overlying solids, and water is squeezed out while the space gets smaller. | 0 | Theoretical and Fundamental Chemistry |
Since its original descriptions, the Urey–Bigeleisen–Mayer equation has taken many forms. Given an isotopic exchange reaction , such that designates a molecule containing an isotope of interest, the equation can be expressed by relating the equilibrium constant, , to the product of partition function ratios, namely the translational, rotational, vibrational, and sometimes electronic partition functions. Thus the equation can be written as: where and is each respective partition function of molecule or atom . It is typical to approximate the rotational partition function ratio as quantized rotational energies in a rigid rotor system. The Urey model also treats molecular vibrations as simplified harmonic oscillators and follows the Born–Oppenheimer approximation.
Isotope partitioning behavior is often reported as a reduced partition function ratio, a simplified form of the Bigeleisen–Mayer equation notated mathematically as or . The reduced partition function ratio can be derived from power series expansion of the function and allows the partition functions to be expressed in terms of frequency. It can be used to relate molecular vibrations and intermolecular forces to equilibrium isotope effects.
As the model is an approximation, many applications append corrections for improved accuracy. Some common, significant modifications to the equation include accounting for pressure effects, nuclear geometry, and corrections for anharmonicity and quantum mechanical effects. For example, hydrogen isotope exchange reactions have been shown to disagree with the requisite assumptions for the model but correction techniques using path integral methods have been suggested. | 0 | Theoretical and Fundamental Chemistry |
Phosphonates are esters of phosphonic acid and have the general formula RP(=O)(OR'). Phosphonates have many technical applications, a well-known member being glyphosate, better known as Roundup. With the formula (HO)P(O)CHNHCHCOH, this derivative of glycine is one of the most widely used herbicides. Bisphosphonates are a class of drugs to treat osteoporosis. The nerve gas agent sarin, containing both C–P and F–P bonds, is a phosphonate.
Phosphinates feature two P–C bonds, with the general formula RP(=O)(OR'). A commercially significant member is the herbicide glufosinate. Similar to glyphosate mentioned above, it has the structure CHP(O)(OH)CHCHCH(NH)COH.
The Michaelis–Arbuzov reaction is the main method for the synthesis of these compounds. For example, dimethylmethylphosphonate (see figure above) arises from the rearrangement of trimethylphosphite, which is catalyzed by methyl iodide. In the Horner–Wadsworth–Emmons reaction and the Seyferth–Gilbert homologation, phosphonates are used in reactions with carbonyl compounds. The Kabachnik–Fields reaction is a method for the preparation of aminophosphonates. These compounds contain a very inert bond between phosphorus and carbon. Consequently, they hydrolyze to give phosphonic and phosphinic acid derivatives, but not phosphate. | 0 | Theoretical and Fundamental Chemistry |
The retention factor (R) may be defined as the ratio of the distance travelled by the solute to the distance travelled by the solvent. It is used in chromatography to quantify the amount of retardation of a sample in a stationary phase relative to a mobile phase. R values are usually expressed as a fraction of two decimal places.
* If R value of a solution is zero, the solute remains in the stationary phase and thus it is immobile.
* If R value = 1 then the solute has no affinity for the stationary phase and travels with the solvent front.
For example, if a compound travels 9.9 cm and the solvent front travels 12.7 cm, the R value = (9.9/12.7) = 0.779 or 0.78. R value depends on temperature and the solvent used in experiment, so several solvents offer several R values for the same mixture of compound. A solvent in chromatography is the liquid the paper is placed in, and the solute is the ink which is being separated. | 0 | Theoretical and Fundamental Chemistry |
The protein structure of firefly luciferase consists of two compact domains: the N-terminal domain and the C-terminal domain. The N-terminal domain is composed of two β-sheets in an αβαβα structure and a β barrel. The two β-sheets stack on top of each other, with the β-barrel covering the end of the sheets.
The C-terminal domain is connected to the N-terminal domain by a flexible hinge, which can separate the two domains. The amino acid sequences on the surface of the two domains facing each other are conserved in bacterial and firefly luciferase, thereby strongly suggesting that the active site is located in the cleft between the domains.
During a reaction, luciferase has a conformational change and goes into a "closed" form with the two domains coming together to enclose the substrate. This ensures that water is excluded from the reaction and does not hydrolyze ATP or the electronically excited product. | 1 | Applied and Interdisciplinary Chemistry |
Coelenterazine was simultaneously isolated and characterized by two groups studying the luminescent organisms sea pansy (Renilla reniformis) and the cnidarian Aequorea victoria, respectively. Both groups independently discovered that the same compound was used in both luminescent systems. The molecule was named after the now-obsolete phylum coelenterata. Likewise, the two main metabolites – coelenteramide and coelenteramine – were named after their respective functional groups. While coelenterazine was first discovered in Aequorea victoria, it was later shown that they do not synthesize coelenterazine, but obtain it through their diet, largely from crustaceans and copepods. | 1 | Applied and Interdisciplinary Chemistry |
Wetlands are dynamic systems that undergo a variety of chemical reactions depending greatly on the specific physicochemical properties of the area, such as temperature, pressure, dissolved organic matter, pH, salinity, and dissolved gases (CO and O). The qualities that have the largest effect are salinity and pH. An increase in flooding (a result of dredging) increases the salinity of wetlands, as it allows saltwater to intrude, neutralizes the pH, and provides more anaerobic soil conditions. The conditions then effect the nutrient availability and redox reactions. | 0 | Theoretical and Fundamental Chemistry |
The equipment required is a colorimeter, some cuvettes and a suitable color reagent. The process may be automated, e.g. by the use of an AutoAnalyzer or by flow injection analysis. Recently, colorimetric analyses developed for colorimeters have been adapted for use with plate readers to speed up analysis and reduce the waste stream. | 0 | Theoretical and Fundamental Chemistry |
Static testing sites provide testing services to clients at fixed locations away from events. Often these are in the entertainment districts of cities. Energy Control in Barcelona and DIMS in the Netherlands provide such services.
Off-site testing occurs away from events and away from clients. Clients submit samples by post or at drop-off locations. Those samples are analysed and then the results are publicised. Examples of this model include WEDINOS (the Welsh Emerging Drugs & Identification of Novel Substances Project) and DIMS in the Netherlands.
The UK's first trial of community-based drug safety testing was carried out in Bristol and Durham in 2018 in a church, a drugs service, and a youth and community centre. Users reported that they intended to carry out a range of harm reduction actions such as alerting friends and acquaintances, being more careful mixing substances, consuming lowered dosage, and disposing of substances.
Drug Checking Programs have been emerging across the Americas in recent years. A directory of these programs can be found at the Harm Reduction Innovation Lab's website. | 0 | Theoretical and Fundamental Chemistry |
Commercial vortex tubes are designed for industrial applications to produce a temperature drop of up to . With no moving parts, no electricity, and no refrigerant, a vortex tube can produce refrigeration up to using 100 standard cubic feet per minute (2.832 m/min) of filtered compressed air at . A control valve in the hot air exhaust adjusts temperatures, flows and refrigeration over a wide range.
Vortex tubes are used for cooling of cutting tools (lathes and mills, both manually-operated and CNC machines) during machining. The vortex tube is well-matched to this application: machine shops generally already use compressed air, and a fast jet of cold air provides both cooling and removal of the chips produced by the tool. This eliminates or drastically reduces the need for liquid coolant, which is messy, expensive, and environmentally hazardous. | 0 | Theoretical and Fundamental Chemistry |
Between depths of 30 and 60 km, oxygen fugacity is mainly controlled by Olivine-Orthopyroxene-Spinel oxidation reaction.
Under deeper upper mantle conditions, Olivine-Orthopyroxene-Garnet oxygen barometer is the redox reaction that is used to calibrate oxygen fugacity.
In this reaction, 4 mole of ferrous ions were oxidized to ferric ions and the other 2 mole of ferrous ions remain unchanged. | 0 | Theoretical and Fundamental Chemistry |
Settleable solids are the particulates that settle out of a still fluid. Settleable solids can be quantified for a suspension using an Imhoff cone. The standard Imhoff cone of transparent glass or plastic holds one liter of liquid and has calibrated markings to measure the volume of solids accumulated in the bottom of the conical container after settling for one hour. A standardized Imhoff cone procedure is commonly used to measure suspended solids in wastewater or stormwater runoff. The simplicity of the method makes it popular for estimating water quality. To numerically gauge the stability of suspended solids and predict agglomeration and sedimentation events, zeta potential is commonly analyzed. This parameter indicates the electrostatic repulsion between solid particles and can be used to predict whether aggregation and settling will occur over time.
The water sample to be measured should be representative of the total stream. Samples are best collected from the discharge falling from a pipe or over a weir, because samples skimmed from the top of a flowing channel may fail to capture larger, high-density solids moving along the bottom of the channel. The sampling bucket is vigorously stirred to uniformly re-suspend all collected solids immediately before pouring the volume required to fill the cone. The filled cone is immediately placed in a stationary holding rack to allow quiescent settling. The rack should be located away from heating sources, including direct sunlight, which might cause currents within the cone from thermal density changes of the liquid contents. After 45 minutes of settling, the cone is partially rotated about its axis of symmetry just enough to dislodge any settled material adhering to the side of the cone. Accumulated sediment is observed and measured fifteen minutes later, after one hour of total settling time. | 0 | Theoretical and Fundamental Chemistry |
A system undergoes a process when one or more of its properties changes. A process relates to the change of state. An isothermal (same-temperature) process occurs when temperature of the system remains constant. An isobaric (same-pressure) process occurs when the pressure of the system remains constant. A process is adiabatic when no heat exchange occurs. | 0 | Theoretical and Fundamental Chemistry |
Mache (symbol ME from German Mache-Einheit, plural Maches) is a unit of volumic radioactivity named for the Austrian physicist Heinrich Mache. It was defined as the quantity of radon (ignoring its daughter isotopes; in practice, mostly radon-222) per litre of air which ionises a sustained current of 0.001 esu (0.001 StatAmpere).
1 ME = 3.64 Eman = 3.64×10 Ci/L = 13.4545 Bq/L. | 0 | Theoretical and Fundamental Chemistry |
The molecular structure of cephalosporin can be altered in various ways to improve in vitro stability, anti-bacterial activity and resistance against β-lactamases. In the acidic conditions of the stomach, in vitro stability can be enhanced by the addition of an amino and a hydrogen to positions α1 and α2 of the cephalosporin structure. This results in a basic compound, an ammonium ion that is protonated in said conditions, giving us a more stable β-lactam which leads to an orally active drug.
Anti-bacterial activity can be enhanced if A2 is an alkoxy group instead of a hydrogen. The 7-amino group is crucial for anti-bacterial activity. In some cases, adding a methoxy group in position A2, cephalosporin stability is enhanced toward β-lactamases.
In position A1, sulfur and oxygen can be placed in the ring. Sulfur shows better anti-bacterial activity, but oxygen shows better stability towards β-lactamases.
In position C6, hydrogen is crucial for biological activity.
In position A3, anti-bacterial activity is greater when A3 is a 5-membered heterocycle instead of a 6-membered one.
In position α1 and α2, the L-isomer is 30–40 times more stable towards β-lactamase than the D-isomer. Stability toward β-lactamase can be increased around 100-fold with the addition of methoxyoxime. Z-oxime is nearly 20,000-fold more stable than the E-oxime. | 1 | Applied and Interdisciplinary Chemistry |
Early explanations for the deep red color of the salt were attributed to the special structure of the crystal lattice, albeit with little explanation. While Drew & Tess attempted to explain the deep color of this compound based on the assumption of a Pt(III) species, Jensen established the diamagnetism of the compound and proved that it did not involve Pt(III). Spectrochemical studies on the compound crystals concluded that the deep color of Wolffram’s salt crystals is due to the stacking of the “infinite chains” - linear Pt(II)/Pt(IV) stacked on top of each other.
In 1960, the crystal structure was shown to be consistent with the formulated double salt, inspiring examinations of other analogues to compare and better understand this unique coordination pattern.
Solid-state physical examinations were conducted to further elucidate the charge transfer across the mixed valence chain and potentially find use as semiconductors. X-ray scattering studies were performed, explicitly showing the mixed valence chain structure. Optical properties were probed, as well as potential use as a photocatalyst, albeit with disappointing results. | 0 | Theoretical and Fundamental Chemistry |
Clay has particles smallest in size (about <0.002 mm) of the particle groups. Clay also has the smallest pores which give it a greater porosity, and it does not drain well. Clay has a sticky texture when wet. Some kinds can grow and dissipate, or in other words shrink and swell. | 0 | Theoretical and Fundamental Chemistry |
Belgian microbiologist Philibert Melchior Joseph Ehi Biourge was the first to describe P. rubens in 1923. The medicinal importance was discovered by Alexander Fleming, a physician at St Marys Hospital, London. In September 1928, Fleming found that one of his bacterial cultures (of Staphylococcus aureus) was contaminated with mould, and that the area around the mould inhibited bacterial growth. He gave the name penicillin for the purported antibacterial substance produced by the mould. After a series of experimental tests, he published his discovery in the June 1929 issue of the British Journal of Experimental Pathology. With the help of his colleague Charles J. La Touche, Fleming identified the fungus as Penicillium rubrum'.
But Charles Thom at the U. S. Department of Agriculture, Peoria, Illinois, compared the specimen with his collection of Penicillium species, and corrected the species as P. notatum. In his publication in 1931, he resolved that P. notatum was a member of P. chrysogenum species complex, which he had described in 1910. P. notatum was described by Swedish chemist Richard Westling in 1811. Thom adopted and popularised the use of P. chrysogenum. After discovery of other new species and taxonomic reexamination, three species, P. notatum, P. meleagrinum, and P. cyaneofulvum were recognised as P. chrysogenum. The Seventeenth International Botanical Congress held in Vienna, Austria, in 2005 adopted the name P. chrysogenum as the conserved name (nomen conservandum).
Whole genome sequence and phylogenetic analysis, particularly using β-tubulin sequences, in 2011 showed that P. notatum is P. rubens, and that P. chrysogenum is a different species. | 1 | Applied and Interdisciplinary Chemistry |
* [http://vlp.mpiwg-berlin.mpg.de/library/data/lit16635 Über den Niederschlag, welchen Pikrinsäre in normalem Harn erzeugt und über eine neue Reaction des Kreatinins] by Max Jaffe (1886) | 1 | Applied and Interdisciplinary Chemistry |
The major disadvantage to the DSSC design is the use of the liquid electrolyte, which has temperature stability problems. At low temperatures the electrolyte can freeze, halting power production and potentially leading to physical damage. Higher temperatures cause the liquid to expand, making sealing the panels a serious problem. Another disadvantage is that costly ruthenium (dye), platinum (catalyst) and conducting glass or plastic (contact) are needed to produce a DSSC. A third major drawback is that the electrolyte solution contains volatile organic compounds (or VOC's), solvents which must be carefully sealed as they are hazardous to human health and the environment. This, along with the fact that the solvents permeate plastics, has precluded large-scale outdoor application and integration into flexible structure.
Replacing the liquid electrolyte with a solid has been a major ongoing field of research. Recent experiments using solidified melted salts have shown some promise, but currently suffer from higher degradation during continued operation, and are not flexible. | 0 | Theoretical and Fundamental Chemistry |
According to Liouville's theorem for Hamiltonian dynamics, the hyper-volume of a cloud of points in phase space remains constant as the system evolves. Therefore, the information entropy must also remain constant, if we condition on the original information, and then follow each of those microstates forward in time:
However, as time evolves, that initial information we had becomes less directly accessible. Instead of being easily summarizable in the macroscopic description of the system, it increasingly relates to very subtle correlations between the positions and momenta of individual molecules. (Compare to Boltzmann's H-theorem.) Equivalently, it means that the probability distribution for the whole system, in 6N-dimensional phase space, becomes increasingly irregular, spreading out into long thin fingers rather than the initial tightly defined volume of possibilities.
Classical thermodynamics is built on the assumption that entropy is a state function of the macroscopic variables—i.e., that none of the history of the system matters, so that it can all be ignored.
The extended, wispy, evolved probability distribution, which still has the initial Shannon entropy S, should reproduce the expectation values of the observed macroscopic variables at time t. However it will no longer necessarily be a maximum entropy distribution for that new macroscopic description. On the other hand, the new thermodynamic entropy S assuredly will measure the maximum entropy distribution, by construction. Therefore, we expect:
At an abstract level, this result implies that some of the information we originally had about the system has become "no longer useful" at a macroscopic level. At the level of the 6N-dimensional probability distribution, this result represents coarse graining—i.e., information loss by smoothing out very fine-scale detail. | 0 | Theoretical and Fundamental Chemistry |
Ionized-air glow is the luminescent emission of characteristic blue–purple–violet light, often of a color called electric blue, by air subjected to an energy flux either directly or indirectly from solar radiation. | 0 | Theoretical and Fundamental Chemistry |
The Euler number (Eu) is a dimensionless number used in fluid flow calculations. It expresses the relationship between a local pressure drop caused by a restriction and the kinetic energy per volume of the flow, and is used to characterize energy losses in the flow, where a perfect frictionless flow corresponds to an Euler number of 0. The inverse of the Euler number is referred to as the Ruark Number with the symbol Ru.
The Euler number is defined as
where
* is the density of the fluid.
* is the upstream pressure.
* is the downstream pressure.
* is a characteristic velocity of the flow.
An alternative definition of the Euler number is given by Shah and Sekulic
where
* is the pressure drop | 1 | Applied and Interdisciplinary Chemistry |
The parabolic model for heat conduction discussed above shows that the Fourier equation (and the more general Fick's law of diffusion) is incompatible with the theory of relativity for at least one reason: it admits infinite speed of propagation of the continuum field (in this case: heat, or temperature gradients). To overcome this contradiction, workers such as Carlo Cattaneo, Vernotte, Chester, and others proposed that Fourier equation should be upgraded from the parabolic to a hyperbolic form, where the n, the temperature field is governed by:
In this equation, C is called the speed of second sound (that is related to excitations and quasiparticles, like phonons). The equation is known as the "hyperbolic heat conduction" (HHC) equation. Mathematically, the above equation is called "telegraph equation", as it is formally equivalent to the telegrapher's equations, which can be derived from Maxwell’s equations of electrodynamics.
For the HHC equation to remain compatible with the first law of thermodynamics, it is necessary to modify the definition of heat flux vector, q, to
where is a relaxation time, such that This equation for the heat flux is often referred to as "Maxwell-Cattaneo equation". The most important implication of the hyperbolic equation is that by switching from a parabolic (dissipative) to a hyperbolic (includes a conservative term) partial differential equation, there is the possibility of phenomena such as thermal resonance and thermal shock waves. | 0 | Theoretical and Fundamental Chemistry |
Finally, biological and bio-hybrid drug carriers have shown potential for chemotactic applications. In general, these systems are inspired by microorganisms or cells to help design drug delivery systems that mimic their surface, shape, texture, and movement. One phenomenon that has become increasingly popular in improving the movement and release of bio-hybrid drug carriers is that of chemotaxis. Indeed, thanks to their natural chemotactic sensing property, bacteria can be used to locate a tumor, carry a therapeutic payload to the site, and release that drug in a controlled manner. Researchers can also genetically modify these bacteria to produce a specific protein like anti-tumor cytotoxins for cancer treatment.
Yet, this is not to say that they dont come with their own set of challenges and limitations. For one, the genetic modifications of the bacteria used can be manipulated by recent or unforeseen mutations, leading to a decrease in the efficacy of the drug and drug carrier. Moreover, the therapeutic proteins produced may have incomplete protein folding, decreasing the drugs effectiveness or causing unforeseen side effects. Generally speaking, using bacteria may provide some advantages, but further research and development are still needed to address their limitations.
Another example of bio-hybrid drug carriers is human cells, like macrophages, which offer compatibility with the human immune system and a simple way to load drugs as a bio-hybrid drug carrier. Leukocytes demonstrate great promise because Tumor cells secrete large amounts of chemoattractants when the cell undergoes inflammation. This secretion of chemoattractants naturally attracts leukocytes, such as macrophages, to the T cell location. Thus, with their well-known chemotactic homing behavior to inflammation or pathogens' sites in mind, researchers can manipulate leukocytes to carry and deliver a therapeutic payload to the tumor site. However, this is not to say that Biological and bio-hybrid drug carriers do not have challenges and limitations of their own. For example, Leukocytes cannot penetrate deeply into the tumors, have a low capacity for carrying drugs, and slow down when the tumor size reduces. Thus, similar to bacteria drug carriers, further research and development are still needed to address their limitations and improve the overall drug delivery system. | 1 | Applied and Interdisciplinary Chemistry |
The following research papers from IUPAC are in pdf format:
*[https://www.iupac.org/publications/pac/1998/pdf/7006x1277.pdf Biodegradable hydrogels for bone regeneration through growth factor release]
*[https://www.iupac.org/publications/pac/2004/pdf/7607x1295.pdf Development of acid-sensitive copolymer micelles for drug delivery] | 1 | Applied and Interdisciplinary Chemistry |
Cytochrome b559 is an important component of Photosystem II (PSII) is a multisubunit protein-pigment complex containing polypeptides both intrinsic and extrinsic to the photosynthetic membrane. Within the core of the complex, the chlorophyll and beta-carotene pigments are mainly bound to the antenna proteins CP43 (PsbC) and CP47 (PsbB), which pass the excitation energy on to chlorophylls in the reaction centre proteins D1 (Qb, PsbA) and D2 (Qa, PsbD) that bind all the redox-active cofactors involved in the energy conversion process. The PSII oxygen-evolving complex (OEC) provides electrons to re-reduce the PSII reaction center, and oxidizes 2 water molecules to recover its reduced initial state. It consists of OEE1 (PsbO), OEE2 (PsbP) and OEE3 (PsbQ). The remaining subunits in PSII are of low molecular weight (less than 10 kDa), and are involved in PSII assembly, stabilisation, dimerization, and photoprotection.
Cytochrome b559, which forms part of the reaction centre core of PSII, is a heterodimer composed of one alpha subunit (PsbE), one beta (PsbF) subunit, and a heme cofactor. Two histidine residues from each subunit coordinate the heme. Although cytochrome b559 is a redox-active protein, it is unlikely to be involved in the primary electron transport in PSII due to its very slow photo-oxidation and photo-reduction kinetics. Instead, cytochrome b559 could participate in a secondary electron transport pathway that helps protect PSII from photo-damage. Cytochrome b559 is essential for PSII assembly.
This domain occurs in both the alpha and beta subunits of cytochrome B559. In the alpha subunit, it occurs together with a lumenal domain (), while in the beta subunit it occurs on its own.
Cytochrome b559 can exist in three forms, each with a characteristic redox potential. These forms are very low potential (VLP), ≤ zero mV; low potential (LP) at 60 mV; and high potential (HP) at 370 mV. There is also an intermediate potential (IP) form that has a redox potential at pH 6.5-7.0 that ranges from 170 to 240 mV. In oxygen-evolving reaction centers, more than half of the cyt b559 is in the HP form. In manganese-depleted non-oxygen evolving photosystem II reaction centers, cyt b559 is usually in the LP form. | 0 | Theoretical and Fundamental Chemistry |
Plasmids were historically used to genetically engineer the embryonic stem cells of rats to create rat genetic disease models. The limited efficiency of plasmid-based techniques precluded their use in the creation of more accurate human cell models. However, developments in adeno-associated virus recombination techniques, and zinc finger nucleases, have enabled the creation of a new generation of isogenic human disease models. | 1 | Applied and Interdisciplinary Chemistry |
Survivin can be regarded as an oncogene as its aberrant overexpression in most cancer cells contributes to their resistance to apoptotic stimuli and chemotherapeutic therapies, thus contributing to their ongoing survival. | 1 | Applied and Interdisciplinary Chemistry |
Zhang was born in China, and moved to Gosford on the Central Coast (New South Wales), Australia at age eight. She credits her mother's stories explaining the scientific basis of various phenomena with stimulating her interest in science. She moved to Sydney to attend the University of Sydney, where she completed a Bachelor of Science (Advanced) in 2007 and a PhD in Chemistry under the supervision of Professor Trevor Hambley in 2011. During her PhD, Zhang also briefly worked at the Hebrew University of Jerusalem. | 0 | Theoretical and Fundamental Chemistry |
These typically consist of a pair of shafts, operated alternately. First, when shaft A is the "primary" and B the "secondary" shaft, the combustion air is added from the top of shaft A, while fuel somewhat below via burner lances. The flame is top-bottom. The hot gases pass downward, cross to shaft B via the so-called "channel" and pass upward to exhaust of shaft B. At same time in both shafts cooling air is added from the bottom to cool the lime and to make exhaust of gases via the bottom of the kiln impossible via maintaining always a positive pressure. The combustion air and cooling air leave the kiln jointly via exhaust on top of shaft B, preheating the stone. The direction of flow is reversed periodically (typically 5–10 times per hour) shaft A and B changing the role of "primary" and "secondary" shaft. The kiln has three zones: preheating zone on the top, burning zone in the middle, and cooling zone close to the bottom. The cycling produces a long burning zone of constant, relatively low temperature (around 950 °C) that is ideal for the production of high quality soft burned reactive lime. With exhaust gas temperatures as low as 120 °C and lime temperature at kiln outlet in 80 °C range the heat loss of the regenerative kiln is minimal, fuel consumption is as low as 3.6 MJ/kg. Due to these features the regenerative kilns are today mainstream technology under conditions of substantial fuel costs. Regenerative kilns are built with 150 to 800 t/day output, 300 to 450 being typical. | 1 | Applied and Interdisciplinary Chemistry |
In the neonatal developmental stages, propionic acidemia, which is a medical issue defined as the lack of propionyl-CoA carboxylase, can cause impairment, mental disability, and numerous other issues. This is caused by an accumulation of propionyl-CoA because it cannot be converted to methylmalonyl-CoA. Newborns are tested for elevated propionylcarnitine. Further ways of diagnosing this disease include urine samples. Medications used help to reverse and prevent recurring symptoms include using supplements to decrease propionate production. | 1 | Applied and Interdisciplinary Chemistry |
Until around 1975, when HEp-2 cells were introduced, animal tissue was used as the standard substrate for immunofluorescence. HEp-2 cells are currently one of the most common substrates for ANA detection by immunofluorescence.
Originally started a laryngeal carcinoma strain, the cell line was contaminated and displaced by HeLa cells, and has now been identified as actually HeLa cells.
They are superior to the previously used animal tissues because of their large size and the high rate of mitosis (cell division) in the cell line. This allows the detection of antibodies to mitosis-specific antigens, such as centromere antibodies. They also allow identification of anti-Ro antibodies, because acetone is used for fixation of the cells (other fixatives can wash the antigen away).
There are many nuclear staining patterns seen on HEp-2 cells: homogeneous, speckled, nucleolar, nuclear membranous, centromeric, nuclear dot and pleomorphic. The homogeneous pattern is seen when the condensed chromosomes and interphase chromatin stain. This pattern is associated with anti-dsDNA antibodies, antibodies to nucleosomal components, and anti-histone antibodies. There are two speckled patterns: fine and coarse. The fine speckled pattern has fine nuclear staining with unstained metaphase chromatin, which is associated with anti-Ro and anti-La antibodies. The coarse staining pattern has coarse granular nuclear staining, caused by anti-U1-RNP and anti-Sm antibodies. The nucleolar staining pattern is associated with many antibodies including anti-Scl-70, anti-PM-Scl, anti-fibrillarin and anti-Th/To. Nuclear membrane staining appears as a fluorescent ring around the cell nucleus and are produced by anti-gp210 and anti-p62 antibodies. The centromere pattern shows multiple nuclear dots in interphase and mitotic cells, corresponding to the number of chromosomes in the cell. Nuclear dot patterns show between 13 and 25 nuclear dots in interphase cells and are produced by anti-sp100 antibodies. Pleomorphic pattern is caused by antibodies to the proliferating cell nuclear antigen. Indirect immunofluorescence has been shown to be slightly superior compared to ELISA in detection of ANA from HEp-2 cells. | 1 | Applied and Interdisciplinary Chemistry |
The chemical and structural properties of protein determine their interactions, and thus their functions, in a wide variety of biochemical processes. Since Ruggeri et al. pioneering work on the aggregation pathways of the Josephin domain of ataxin-3, responsible for type-3 spinocerebellar ataxia, an inheritable protein-misfolding disease, AFM-IR was used to characterize molecular conformations in a wide spectrum of applications in protein and life sciences. This approach has delivered new mechanistic insights into the behaviour of disease-related proteins and peptides, such as Aβ42, huntingtin and FUS, which are involved in the onset of Alzheimers, Huntingtons and Amyotrophic lateral sclerosis (ALS). Similarly AFM-IR has been applied to study studying protein based functional biomaterials. | 0 | Theoretical and Fundamental Chemistry |
The gallium antimonide (GaSb) PV cell, invented in 1989, is the basis of most PV cells in modern TPV systems. GaSb is a III-V semiconductor with the zinc blende crystal structure. The GaSb cell is a key development owing to its narrow bandgap of 0.72 eV. This allows GaSb to respond to light at longer wavelengths than silicon solar cell, enabling higher power densities in conjunction with manmade emission sources. A solar cell with 35% efficiency was demonstrated using a bilayer PV with GaAs and GaSb, setting the solar cell efficiency record.
Manufacturing a GaSb PV cell is quite simple. Czochralski tellurium-doped n-type GaSb wafers are commercially available. Vapor-based zinc diffusion is carried out at elevated temperatures (~450 °C) to allow for p-type doping. Front and back electrical contacts are patterned using traditional photolithography techniques and an anti-reflective coating is deposited. Efficiencies are estimated at ~20% using a 1000 °C black body spectrum. The radiative limit for efficiency of the GaSb cell in this setup is 52%. | 0 | Theoretical and Fundamental Chemistry |
The cnoidal wave solutions of the KdV equation were presented by Korteweg and de Vries in their 1895 paper, which article is based on the PhD thesis by de Vries in 1894. Solitary wave solutions for nonlinear and dispersive long waves had been found earlier by Boussinesq in 1872, and Rayleigh in 1876. The search for these solutions was triggered by the observations of this solitary wave (or "wave of translation") by Russell, both in nature and in laboratory experiments. Cnoidal wave solutions of the KdV equation are stable with respect to small perturbations.
The surface elevation η(x,t), as a function of horizontal position x and time t, for a cnoidal wave is given by:
where H is the wave height, λ is the wavelength, c is the phase speed and η is the trough elevation. Further cn is one of the Jacobi elliptic functions and K(m) is the complete elliptic integral of the first kind; both are dependent on the elliptic parameter m. The latter, m, determines the shape of the cnoidal wave. For m equal to zero the cnoidal wave becomes a cosine function, while for values close to one the cnoidal wave gets peaked crests and (very) flat troughs. For values of m less than 0.95, the cnoidal function can be approximated with trigonometric functions.
An important dimensionless parameter for nonlinear long waves (λ ≫ h) is the Ursell parameter:
For small values of U, say U < 5, a linear theory can be used, and at higher values nonlinear theories have to be used, like cnoidal wave theory. The demarcation zone between—third or fifth order—Stokes and cnoidal wave theories is in the range 10–25 of the Ursell parameter. As can be seen from the formula for the Ursell parameter, for a given relative wave height H/h the Ursell parameter—and thus also the nonlinearity—grows quickly with increasing relative wavelength λ/h'.
Based on the analysis of the full nonlinear problem of surface gravity waves within potential flow theory, the above cnoidal waves can be considered the lowest-order term in a perturbation series. Higher-order cnoidal wave theories remain valid for shorter and more nonlinear waves. A fifth-order cnoidal wave theory was developed by Fenton in 1979. A detailed description and comparison of fifth-order Stokes' and fifth-order cnoidal wave theories is given in the review article by Fenton.
Cnoidal wave descriptions, through a renormalisation, are also well suited to waves on deep water, even infinite water depth; as found by Clamond. A description of the interactions of cnoidal waves in shallow water, as found in real seas, has been provided by Osborne in 1994. | 1 | Applied and Interdisciplinary Chemistry |
Boltwood is credited as being the first to introduce a uranium-lead dating technique to determine the age of geological samples. The discovery stemmed from his investigations of the uranium decay series and conversations with Rutherford. In 1904, Rutherford gave lectures around the topic of radioactivity as a tool for geologic dating, and presented calculations based on the presence of helium as a product. He dated a sample of fergusonite at 40 million years, with the caveat that helium could escape and would therefore only provide a minimum age. The following year, Boltwood made the assertion that lead was the final decay product in the disintegration of uranium, and that Pb:U ratios increase in older geological samples. In 1907, he published results of analyzing ten mineral samples from different world locations, including a thorianite that measured 2.2 billion years old. This value was ten times greater than any previous estimated age of the Earth, and geologists did not immediately accept the validity of radioactivity as a dating method. Boltwood published a single paper on radiometric dating, instead focusing the majority of his research on the uranium decay series. | 0 | Theoretical and Fundamental Chemistry |
Takamine Tokumei from Shuri, Ryūkyū Kingdom, is reported to have made a general anesthesia in 1689 in the Ryukyus, now known as Okinawa. He passed on his knowledge to the Satsuma doctors in 1690 and to Ryūkyūan doctors in 1714.
Hanaoka Seishū (華岡 青洲, 1760–1835) of Osaka was a Japanese surgeon of the Edo period with a knowledge of Chinese herbal medicine, as well as Western surgical techniques he had learned through Rangaku (literally "Dutch learning", and by extension "Western learning"). Beginning in about 1785, Hanaoka embarked on a quest to re-create a compound that would have pharmacologic properties similar to Hua Tuos mafeisan. After years of research and experimentation, he finally developed a formula which he named tsūsensan (also known as mafutsu-san'). Like that of Hua Tuo, this compound was composed of extracts of several different plants, including:
* 2 parts bai zhi (Chinese:白芷，Angelica dahurica);
* 2 parts cao wu (Chinese:草烏，Aconitum sp., monkshood or wolfsbane);
* 2 parts chuān ban xia (Pinellia ternata);
* 2 parts chuān xiōng (Ligusticum wallichii, Cnidium rhizome, Cnidium officinale or Szechuan lovage);
* 2 parts dong quai (Angelica sinensis or female ginseng);
* 1 part tian nan xing (Arisaema rhizomatum or cobra lily)
* 8 parts yang jin hua (Datura stramonium, Korean morning glory, thorn apple, jimson weed, devils trumpet, stinkweed, or locoweed').
The active ingredients in tsūsensan are scopolamine, hyoscyamine, atropine, aconitine and angelicotoxin. When consumed in sufficient quantity, tsūsensan produces a state of general anesthesia and skeletal muscle paralysis. Shutei Nakagawa (1773–1850), a close friend of Hanaoka, wrote a small pamphlet titled "Mayaku-ko" ("narcotic powder") in 1796. Although the original manuscript was lost in a fire in 1867, this brochure described the current state of Hanaoka's research on general anesthesia.
On 13 October 1804, Hanaoka performed a partial mastectomy for breast cancer on a 60-year-old woman named Kan Aiya, using tsūsensan as a general anaesthetic. This is generally regarded today as the first reliable documentation of an operation to be performed under general anesthesia. Hanaoka went on to perform many operations using tsūsensan, including resection of malignant tumors, extraction of bladder stones, and extremity amputations. Before his death in 1835, Hanaoka performed more than 150 operations for breast cancer. | 1 | Applied and Interdisciplinary Chemistry |
The aim of MOSE is to protect the lagoon, its towns, villages, and inhabitants along with its iconic historic, artistic, and environmental heritage from floods, including extreme events.
Although the tide in the lagoon basin is lower than in other areas of the world (where it may reach as high as ), the phenomenon may become significant when associated with atmospheric and meteorological factors such as low pressure and the bora, a north-easterly wind coming from Trieste, or the Sirocco, a hot south-easterly wind. Those conditions push waves into the gulf of Venice. High water is also worsened by rain and water flowing into the lagoon from the drainage basin at 36 inflow points associated with small rivers and canals.
Floods have caused damage since ancient times and have become ever more frequent and intense as a result of the combined effect of eustatism (a rise in sea level) and subsidence (a drop in land level) caused by natural and man-induced phenomena. Today, towns and villages in the lagoon are an average of lower with respect to the water level than at the beginning of the 1900s and each year, thousands of floods cause serious problems for the inhabitants as well as deterioration of architecture, urban structures and the ecosystem. Over the entire lagoon area, there is also a constant risk of an extreme catastrophic event such as that of 4November 1966 (the great flood) when a tide of submerged Venice, Chioggia and the other built-up areas.
Floods effects are exacerbated due to greater erosion by the sea caused by human interventions to facilitate port activities (e.g. through the construction of jetties and artificial canals); establishment of the industrial Porto Marghera area; and increased wash from motorized boats, which all aggravate erosion of morphological structures and the foundations of quaysides and buildings.
In the future, the high water phenomenon may be further aggravated by the predicted rise in sea level as a result of global warming.
In this context, MOSE, together with reinforcement of the barrier island, has been designed to provide protection from tides of up to in height. The aim of MOSE is to protect the lagoon, even if the most pessimistic hypotheses are proven true, such as a rise in sea level of at least . However, the reports have grown more pessimistic with time compared to when MOSE was originally planned; the 2019 estimate from the IPCC (Intergovernmental Panel on Climate Change) predicts a rise in sea level of between by 2100 if emissions continue to increase, which MOSE was not designed to handle.
MOSE is flexible and can be operated in different ways according to the characteristics and height of the tide. Given that the gates are independent and can be operated separately, all three inlets can be closed in the case of an exceptional event, the inlets can be closed one at a time according to the winds, atmospheric pressure and height of tide forecast, or again, each inlet can be partially closed.
Exceptionally high waters have struck the city since 1935: levels of 140 cm or greater have been recorded during the following floods, with 12 of the 20 events occurring in the 21st century:
Prior to 1936, the highest levels had been in 1879, when on 25 February the water reached 137.5 cm, and on 21 November 1916, when a level of 136 cm occurred. Since 1936, there have been 17 occasions when the level reached between 130 and 140 cm.
All values were recorded at the monitoring station at Punta della Salute (Punta della Dogana) and refer to the 1897 tidal datum point.
The highest tide in over five decades | 1 | Applied and Interdisciplinary Chemistry |
9-Borabicyclo[3.3.1]nonane or 9-BBN is an organoborane compound. This colourless solid is used in organic chemistry as a hydroboration reagent. The compound exists as a hydride-bridged dimer, which easily cleaves in the presence of reducible substrates. 9-BBN is also known by its nickname banana borane. This is because rather than drawing out the full structure, chemists often simply draw a banana shape with the bridging boron. | 0 | Theoretical and Fundamental Chemistry |
The ages of domestic cats and dogs are often referred to in terms of "cat years" or "dog years", representing a conversion to human-equivalent years. One formula for cat years is based on a cat reaching maturity in approximately 1 year, which could be seen as 16 in human terms, then adding about 4 years for every year the cat ages. A 5-year-old cat would then be (5 − 1) × 4 + 16 = 32 "cat years" (i.e. human-equivalent years), and a 10-year-old cat (10 − 1) × 4 + 16 = 52 in human terms. | 1 | Applied and Interdisciplinary Chemistry |
In the short flap pathway in eukaryotes the lagging strand of DNA is primed in short intervals. In the short pathway only, the nuclease FEN1 is involved. Pol δ frequently encounters the downstream primed Okazaki fragment and displaces the RNA/DNA initiator primer into a 5′ flap. The FEN1 5’-3’ endonuclease recognizes that the 5’ flap is displaced, and it cleaves, creating a substrate for ligation. In this method the Pol a-synthesized primer is removed. Studies show that in the FEN1 suggest a ‘tracking; model where the nuclease moves from the 5’ flap to its base to preform cleavage. The Pol δ does not process a nuclease activity to cleave the displaced flap. The FEN1 cleaves the short flap immediately after they form. The cleavage is inhibited when the 5’ end of the DNA flap is blocked either with a complementary primer or a biotin-conjugated streptavidin moiety. DNA ligase seals the nick made by the FEN1 and it creates a functional continuous double strand of DNA. PCNA simulates enzymatic functions of proteins for both FEN1 and DNA ligase. The interaction is crucial in creating proper ligation of the lagging DNA strand. Sequential strand displacement and cleavage by Pol δ and FEN1, respectively, helps to remove the entire initiator RNA before ligation. Many displacements need to take place and cleavage reactions are required to remove the initiator primer. The flap that is created and processes and it is matured by the short flap pathway. | 1 | Applied and Interdisciplinary Chemistry |
Phenotypic screening historically has been the basis for the discovery of new drugs. Compounds are screened in cellular or animal disease models to identify compounds that cause a desirable change in phenotype. Only after the compounds have been discovered are efforts made to determine the biological targets of the compounds - a process known as target deconvolution. This overall strategy is referred to as "classical pharmacology", "forward pharmacology" or "phenotypic drug discovery" (PDD).
More recently it has become popular to develop a hypothesis that a certain biological target is disease modifying, and then screen for compounds that modulate the activity of this purified target. Afterwards, these compounds are tested in animals to see if they have the desired effect. This approach is known as "reverse pharmacology" or "target based drug discovery" (TDD). However recent statistical analysis reveals that a disproportionate number of first-in-class drugs with novel mechanisms of action come from phenotypic screening which has led to a resurgence of interest in this method. | 1 | Applied and Interdisciplinary Chemistry |
Cleve was born in Stockholm, Sweden, as the thirteenth child of his father, a merchant known as Fredrik Theodor Cleve. Cleves ancestors on his fathers side came from western Germany and settled in Sweden in the late 18th century.
Cleve showed interest in natural science and natural history from an early age. He attended the Stockholms Lyceum in 1858, studying chemistry and biology. He gained a Bachelor of Science degree from the University of Uppsala in 1863 and a PhD from the same university in 1868. | 1 | Applied and Interdisciplinary Chemistry |
1,3 Diaxial interactions occur when the non-hydrogen substituent on a cyclohexane occupies the axial position. This axial substituent is in the eclipsed position with the axial substituents on the 3-carbons relative to itself (there will be two such carbons and thus two 1,3 diaxial interactions). This eclipsed position increases the steric strain on the cyclohexane conformation and the confirmation will shift towards a more energetically favorable equilibrium.
Gauche interactions occur when a non-hydrogen substituent on a cyclohexane occupies the equatorial position. The equatorial substituent is in a staggered position with the 2-carbons relative to itself (there will be two such carbons and thus two 1,2 gauche interactions). This creates a dihedral angle of ~60°. This staggered position is generally preferred to the eclipsed positioning. | 0 | Theoretical and Fundamental Chemistry |
The possibility to measure forces involving particles and surfaces directly is essential since such forces are relevant in a variety of processes involving colloidal and polymeric systems. Examples include particle aggregation, suspension rheology, particle deposition, and adhesion processes. One can equally study similar biological phenomena, such as deposition of bacteria or the infection of cells by viruses. Forces are equally most informative to investigate the mechanical properties of interfaces, bubbles, capsules, membranes, or cell walls. Such measurements permit to make conclusions about the elastic or plastic deformation or eventual rupture in such systems.
The colloidal probe technique provides a versatile tool to measure such forces between a colloidal particle and a planar substrate or between two colloidal particles (see figure above). The particles used in such experiments have typically a diameter between 1–10 μm. Typical applications involve measurements of electrical double layer forces and the corresponding surface potentials or surface charge, van der Waals forces, or forces induced by adsorbed polymers. | 0 | Theoretical and Fundamental Chemistry |
A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness, or helicity, for that particle, which, in the case of a massless particle, is the same as chirality. A symmetry transformation between the two is called parity transformation. Invariance under parity transformation by a Dirac fermion is called chiral symmetry. | 0 | Theoretical and Fundamental Chemistry |
MedChemComm (in full: Medicinal Chemistry Communications) is a peer-reviewed scientific journal publishing original (primary) research and review articles on all aspects of medicinal chemistry, including drug discovery, pharmacology and pharmaceutical chemistry. Until December 2019, it was published monthly by the Royal Society of Chemistry in partnership with the European Federation for Medicinal Chemistry, of which it was the official journal. Authors can elect to have accepted articles published as open access. According to the Journal Citation Reports, the journal has a 2014 impact factor of 2.495, ranking it 27th out of 59 journals in the category "Chemistry, Medicinal" and 163 out of 289 journals in the category "Biochemistry & Molecular Biology".
The editor-in-chief is Mike Waring (Newcastle University).
As of January 1, 2020 - the journal is now called RSC Medicinal Chemistry and continues to be published monthly under this new name. | 1 | Applied and Interdisciplinary Chemistry |
Criticism of NeSSI mechanical systems have included higher initial cost, inability to troubleshoot at a component level (due to compact/intensive spacing), and the lack of performance data associated with the use of elastomeric seals in long term installations. From a design perspective, it may be difficult to design a modular, mechanical system which meets the needs of the diverse process applications found in industry. Development of the NeSSI-bus has been an iterative exercise, and it will need the close cooperation of both component and analyzer manufacturers to make their equipment NeSSI-bus compliant. At this time, there are missing elements such as a low cost, low power flow sensor which is capable of providing a continuous reading of sample system flow as well as a proportional, miniature control valve.
The predicted impact of NeSSI systems are as follows:
* Adoption of a universally accepted method of protection (intrinsic safety) for sample systems will globalize and harmonize system design and help overcome geographical restrictions currently mandated by various electrical certification/approval bodies such as Factory Mutual (FM) and Underwriters Laboratories (UL), ATEX (Europe), GOST (Russian Federation) and Canadian Standards Association (CSA).
* Analyzer technical staff will have the capability of accessing the status of all the key indicators of analytical sample system performance both locally and remotely. Predictive rather than preventive maintenance can be performed and remote diagnostics and graphical user interfaces are the norm. Analyzer rounds will be eliminated. Analyzer systems will become more reliable and trustworthy. The analyzer technician will have the power to configure a sampling/analytical system, as he/she desires using the smart applets. The adjustable wrench and screwdriver will be replaced with software.
* Molecular management meaning tighter process control by more analysis of the chemical processes - will become feasible with better, faster, less costly and more abundant analysis. This will help reduce manufacturing energy costs and minimize environmental emissions in the process industries.
Since its debut in 2000, NeSSI the mechanical portion has seen gradual but steady acceptance in industry. Currently, there are three major commercial suppliers of NeSSI compliant mechanical systems along with dozens of components available for mounting on these systems. There is also a growing list of companies implementing NeSSI systems in their manufacturing and pilot-plant facilities. Recently, two of the largest suppliers of process analyzers have committed to supporting NeSSI hardware and the development of the intrinsically safe NeSSI-bus communication into their products. NeSSI is gaining status as a de facto standard for many process sampling system applications.
NeSSI (Generation I) acceptance has spread beyond its initial chemical and petrochemical industry roots to find applications in the automotive, food, and pharmaceutical industries, as well as applications as an analytical development system in research laboratories. Generation II electrical systems are now close to commercialization with the first industrial systems scheduled for operation in 2008. | 1 | Applied and Interdisciplinary Chemistry |
Nanoelectrodes are tiny electrodes made of metals or semiconducting materials having typical dimensions of 1-100 nm.
Various forms of nanoelectrodes have been developed taking advantage of the different possible fabrication techniques: among the most studied are the nanoband, disk, hemispherical, nanopore geometries as well as the different forms of carbon nanostructures.
It is necessary to characterize each produced electrode: size and shape determine its behavior. The most used characterization techniques are:
* Electron microscopy
* Steady-state voltammetry
* Atomic force microscopy (AFM)
* scanning electrochemical microscopy (SECM)
There are mainly two properties that distinguish nanoelectrodes from electrodes: smaller RC constant and faster mass transfer. The former allows measurements to be made in high-resistance solutions because they offer less resistance, the latter, due to radial diffusion, allows much faster voltammetry responses. Due to these and other properties, nanoelectrodes are used in various applications:
* Studying the kinetics of fast reactions
* Electrochemical reactions
* Studying small volumes, such as cells or single molecules
* As probes for obtaining high-resolution images with scanning electrochemical microscopy (SECM) | 0 | Theoretical and Fundamental Chemistry |
Real-time PCR is carried out in a thermal cycler with the capacity to illuminate each sample with a beam of light of at least one specified wavelength and detect the fluorescence emitted by the excited fluorophore. The thermal cycler is also able to rapidly heat and chill samples, thereby taking advantage of the physicochemical properties of the nucleic acids and DNA polymerase.
The PCR process generally consists of a series of temperature changes that are repeated 25–50 times. These cycles normally consist of three stages: the first, at around 95 °C, allows the separation of the nucleic acid's double chain; the second, at a temperature of around 50–60 °C, allows the binding of the primers with the DNA template; the third, at between 68 and 72 °C, facilitates the polymerization carried out by the DNA polymerase. Due to the small size of the fragments the last step is usually omitted in this type of PCR as the enzyme is able to replicate the DNA amplicon during the change between the alignment stage and the denaturing stage. In addition, in four-step PCR the fluorescence is measured during short temperature phases lasting only a few seconds in each cycle, with a temperature of, for example, 80 °C, in order to reduce the signal caused by the presence of primer dimers when a non-specific dye is used. The temperatures and the timings used for each cycle depend on a wide variety of parameters, such as: the enzyme used to synthesize the DNA, the concentration of divalent ions and deoxyribonucleotide triphosphates (dNTPs) in the reaction and the bonding temperature of the primers. | 1 | Applied and Interdisciplinary Chemistry |
Many useful organic reactions involve the formation of tetrahedral intermediates through nucleophilic attack of functional groups such as aldehydes, amides or imines. In these cases, catalysis with hydrogen-bond donors is an attractive strategy since the anionic tetrahedral intermediates are better hydrogen-bond acceptors than the starting compound. This means that relative to the initial catalyst-substrate complex, the transition state, bearing more negative charge, is stabilized.
For example, in a typical acyl substitution reaction, the starting carbonyl compound is coordinated to the catalyst through one, two or possibly more hydrogen bonds. During the attack of the nucleophile, negative charge builds on the oxygen until the tetrahedral intermediate is reached. Therefore, the formally negative oxygen engages in a much stronger hydrogen bond than the starting carbonyl oxygen because of its increased negative charge. Energetically, this has the effect of lowering the intermediate and the transition state, thus accelerating the reaction.
This mode of catalysis is found in the active sites of many enzymes, such as the serine proteases. In this example, the amide carbonyl is coordinated to two N–H donors. These sites of multiple coordination designed to promote carbonyl reactions in biology are termed "oxyanion holes". Delivery of serine nucleophile forms a tetrahedral intermediate, which is stabilized by the increase hydrogen bonding to the oxyanion hole.
Many synthetic catalysts have been able to successfully employ this strategy to activate a variety of electrophiles. Using a chiral BINOL catalyst, for instance, the Morita-Baylis-Hillman reaction involving the addition of enones to aldehydes can be effected with high enantioselectivity. The nucleophile is an enolate-type species generated from the conjugate addition of PEt to the enone, and adds enantioselectively to the aldehyde coordinated to catalyst.
In addition to carbonyls, other electrophiles such as imines can be successfully used. For example, using a simple chiral thiourea catalyst, the asymmetric Mannich reaction of aromatic imines with silyl ketene acetals can be catalyzed with high ee in near quantitative conversion. The mechanism of this reaction is not fully resolved and the reaction is very substrate-specific, only effective on certain aromatic electrophiles.
The scope of this mode of activation is immense, with constant new reports of different combinations of electrophiles, nucleophiles and catalyst structures. Furthermore, analogous reactions involving oxyanion intermediates such as enolate addition to nitroso compounds or opening of epoxides have also been successfully catalyzed with this strategy.
However, despite the number of different reactions known, general understanding of the mode of catalysis is limited, and almost all reactions discovered are extremely substrate specific. | 0 | Theoretical and Fundamental Chemistry |
The homopolymers of acrylate esters (e.g., butyl acrylate) have few applications. Copolymers however have many applications/ They are produced by copolymerization of alkyl acrylates and one or more of the following comonomers methyl methacrylate, styrene, acrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, and butadiene. | 0 | Theoretical and Fundamental Chemistry |
Supramolecular assembly requires non-covalent interactions directing the formation of 2D polymers by relying on electrostatic interactions such as hydrogen bonding and van der Waals forces. To design artificial assemblies capable of high selectivity requires correct manipulation of energetic and stereochemical features of non-covalent forces. Some benefits of non-covalent interactions is their reversible nature and response to external factors such as temperature and concentration. The mechanism of non-covalent polymerization in supramolecular chemistry is highly dependent on the interactions during the self-assembly process. The degree of polymerization depends highly on temperature and concentration. The mechanisms may be divided into three categories: isodesmic, ring-chain, and cooperative.
One example of isodesmic associations in supramolecular aggregates is seen in Figure 7, (CA*M) cyanuric acid (CA) and melamine (M) interactions and assembly through hydrogen bonding. Hydrogen bonding has been used to guide assembly of molecules into two-dimensional networks, that can then serve as new surface templates and offer an array of pores of sufficient capacity to accommodate large guest molecules. An example of utilizing surface structures through non-covalent assembly uses adsorbed monolayers to create binding sites for target molecules through hydrogen bonding interactions. Hydrogen bonding is used to guide the assembly of two different molecules into a 2D honeycomb porous network under ultra high vacuum seen in figure 8. 2D polymers based on DNA have been reported | 0 | Theoretical and Fundamental Chemistry |
Denaturing High Performance Liquid Chromatography (DHPLC) is a method of chromatography for the detection of base substitutions, small deletions or insertions in the DNA. Thanks to its speed and high resolution, this method is particularly useful for finding polymorphisms in DNA.
In practice, the analysis begins with a standard PCR in order to amplify the fragment of interest. If the amplified region that exhibits the polymorphism(s) is heterozygous, two kinds of fragments corresponding to the allele and the wild polymorphic allele will be present in the PCR product. This first step is followed by a step of denaturation–renaturation to create hetero- and homoduplexes from the two allele populations in the PCR. To find a homozygous polymorphism, proceed in the same way by premixing a DNA wild population to a population of polymorphic DNA to obtain heteroduplexes after the denaturation–renaturation step.
Heteroduplexes are actually double strands of DNA containing a strand from the wild-type allele and a sprig from the polymorphic allele. The formation of such DNA fragments then causes the appearance of a "mismatch" or bad pairing where the polymorphism is located.
These "mismatches" in the heteroduplex are the basis for the polymorphism detection by DHPLC. Heteroduplexes are thermally less stable than their corresponding homoduplexes, and the single DNA strands will therefore be disconnected by chromatography when subjected to a sufficiently high temperature. The consequence of this double strand instability will be a mismatch of the two DNA strands in the region of polymorphism when DNA is heated to the DNA melting temperature. This mismatch will therefore decrease the interaction with the column and will result in a reduced retention time compared to the homoduplexes in the chromatographic separation process.
To observe the phenomenon of separation, the DHPLC method uses a column of a non-grafted porous stationary phase composed of polystyrene-divinylbenzene alkyl. The stationary phase is electrically neutral and hydrophobic. The DNA, however, is negatively charged at its phosphate groups and therefore can adsorb itself on the column. In order to make the adsorption possible, triethylammonium acetate (TEAA) is used. The positively charged ammonium ion of these molecules interacts with the DNA, and the alkyl chain with the hydrophobic surface of the solid phase.
Therefore, when heteroduplexes are partially denaturated by heating, the negative charges undergo partial relocation and the interaction force between DNA heteroduplexes and column decreases in comparison to the strength of interaction of the homoduplexes. These will therefore be eluted less rapidly by the mobile phase (consisting of acetonitrile). | 0 | Theoretical and Fundamental Chemistry |
Due to the experimental ease of its use, BMS has become common in hydroboration reactions. In hydroborations with BMS, the dimethylsulfide dissociates in situ, liberating diborane, which rapidly adds to the unsaturated bonds. The resulting organoborane compounds are useful intermediates in organic synthesis. Boranes add to alkenes in an anti-Markovnikov fashion and allow conversion of alkynes to the corresponding cis-alkenes. | 0 | Theoretical and Fundamental Chemistry |
"Salen-type" metal complexes are formed with ligands with similar chelating groups, such as acacen, salph, and salqu. Salqu copper complexes have been investigated as oxidation catalysts. | 0 | Theoretical and Fundamental Chemistry |
In 1964, Girard Henderson had an underground home built on a mountain ranch located near Ward, Colorado.
The construction was completed by builders Julian "Jay" and Kenneth Swayze, from Plainview, Texas. The Swayze brothers established a company known as Underground World Homes, specializing in the design and construction of full-sized underground residences. On May 13, 1963, Swayze initiated the process of securing a patent for his underground home design. Patent US3227061A was officially granted to Swayze on January 4, 1966, recognizing the underground home concept. This patent marked a milestone in the development of underground dwelling technologies. Swayze's approach led them to create various underground homes, including one that Jay Swayze resided in with his wife and two daughters called Atomitat. It was the first home in the U.S. to meet civil defense specifications for a nuclear shelter. Henderson became intrigued by the idea and decided to invest, acquiring a 51 percent share of Underground World Homes.
During that same year, Henderson undertook the construction of an almost identical underground home, sponsoring the Underground World Home exhibit at the 1964 New York World's Fair, copying the concept pioneered by the Swayze brothers.
Henderson and his wife spent time on the property.
The Swayze brothers authored a book titled Underground Gardens & Homes: The best of two worlds, above and below. Published in 1980, the book delved into the nuclear age, addressing the imperative need for comprehensive planning to safeguard ourselves from potential adverse consequences.
Situated northwest of Boulder, Colorado and at an elevation of above sea level, the dwelling, dubbed "Mountain Home" by its contractors, employed a building technique known as "ship-in-a-bottle", that deployed mountain top removal, followed by the pouring of a concrete shell, and finally the reinstatement of the mountain top. | 0 | Theoretical and Fundamental Chemistry |
Supersonic flow over a flat plate is a classical fluid dynamics problem. There is no exact solution to it. | 1 | Applied and Interdisciplinary Chemistry |
Geometallurgy relates to the practice of combining geology or geostatistics with metallurgy, or, more specifically, extractive metallurgy, to create a spatially or geologically based predictive model for mineral processing plants. It is used in the hard rock mining industry for risk management and mitigation during mineral processing plant design. It is also used, to a lesser extent, for production planning in more variable ore deposits.
There are four important components or steps to developing a geometallurgical program,:
*the geologically informed selection of a number of ore samples
*laboratory-scale test work to determine the ore's response to mineral processing unit operations
*the distribution of these parameters throughout the orebody using an accepted geostatistical technique
*the application of a mining sequence plan and mineral processing models to generate a prediction of the process plant behavior | 1 | Applied and Interdisciplinary Chemistry |
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