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The Segré–Silberberg effect is a fluid dynamic separation effect where a dilute suspension of neutrally buoyant particles flowing (in laminar flow) in a tube equilibrates at a distance of 0.6R from the tube's centre. This effect was first observed by Segré and Silberberg. The solid particles are subjected to both viscous drag forces and inertial lift forces. The drag forces are responsible for driving particles along the flow streamlines, whereas the inertial forces are responsible for the lateral migration of particles across the flow streamlines. The parabolic nature of the laminar velocity profile in Poiseuille flow produces a shear-induced inertial lift force that drives particles towards the channel walls. As particles migrate closer to the channel walls, the flow around the particle induces a pressure increase between the particle and the wall which prevents particles of moving closer. The opposing lift forces are dependent on the particle diameter to channel diameter
ratio (), and dominate for . | 1 | Applied and Interdisciplinary Chemistry |
In general, protein kinases are classified in two major categories based on their substrate specificity, protein tyrosine kinases and protein serine/threonine kinases. Dual-specificity kinases are subclass of the tyrosine kinases.
mTOR is a kinase within the family of phosphatidylinositol-3 kinase-related kinases (PIKKs), which is a family of serine/threonine protein kinases, with a sequence similarity to the family of lipid kinases, PI3Ks. These kinases have different biological functions, but are all large proteins with common domain structure.
PIKKs have four domains at the protein level, which distinguish them from other protein kinases. From the N-terminus to the C-terminus, these domains are named FRAP-ATM-TRAAP (FAT), the kinase domain (KD), the PIKK-regulatory domain (PRD), and the FAT-C-terminal (FATC). The FAT domain, consisting of four α-helices, is N-terminal to KD, but that part is referred to as the FKBP12-rapamycin-binding (FRB) domain, which binds the FKBP12-rapamycin complex. The FAT domain consists of repeats, referred to as HEAT (Huntingtin, Elongation factor 3, A subunit of protein phosphatase 2A and TOR1). Specific protein activators regulate the PIKK kinases but binding of them to the kinase complex causes a conformational change that increases substrate access to the kinase domain.
Protein kinases have become popular drug targets. They have been targeted for the discovery and design of small molecule inhibitors and biologics as potential therapeutic agents. Small-molecule inhibitors of protein kinases generally prevent either phosphorylation of proteins substrates or autophosphorylation of the kinase itself. | 1 | Applied and Interdisciplinary Chemistry |
An example reference range for transferrin is 204–360 mg/dL. Laboratory test results should always be interpreted using the reference range provided by the laboratory that performed the test.
A high transferrin level may indicate an iron deficiency anemia. Levels of serum iron and total iron binding capacity (TIBC) are used in conjunction with transferrin to specify any abnormality. See interpretation of TIBC. Low transferrin likely indicates malnutrition. | 1 | Applied and Interdisciplinary Chemistry |
In 2018, Bio-Rad Laboratories filed a lawsuit against 10x Genomics stating that their linked-read technology infringed on three patents which had been licensed from Bio-Rad at the University of Chicago. Bio-Rad was awarded a sum of $23,930,716 by a jury. The 10x Genomics filed a motion for judgement as a matter of law (JMOL) but were denied in 2019, and the court proceedings concluded in 2020. Following this lawsuit, 10x Genomics discontinued their linked-read assay. An exception was made for linked-read products which had already been sold by the company prior to the lawsuit, allowing 10x Genomics to continue to provide those researchers with services such as support and warranty maintenance for this technology. | 1 | Applied and Interdisciplinary Chemistry |
The resurgence of RNA structural biology in the mid-1990s has caused a veritable explosion in the field of nucleic acid structural research. Since the publication of the hammerhead and P structures, numerous major contributions to the field have been made. Some of the most noteworthy examples include the structures of the Group I and Group II introns, and the Ribosome solved by Nenad Ban and colleagues in the laboratory of Thomas Steitz. The first three structures were produced using in vitro transcription, and that NMR has played a role in investigating partial components of all four structures—testaments to the indispensability of both techniques for RNA research. Most recently, the 2009 Nobel Prize in Chemistry was awarded to Ada Yonath, Venkatraman Ramakrishnan and Thomas Steitz for their structural work on the ribosome, demonstrating the prominent role RNA structural biology has taken in modern molecular biology. | 1 | Applied and Interdisciplinary Chemistry |
The word "litmus" comes from an Old Norse word for “moss used for dyeing”. About 1300, the Spanish physician Arnaldus de Villa Nova began using litmus to study acids and bases.
From the 16th century onwards, the blue dye was extracted from some lichens, especially in the Netherlands. | 0 | Theoretical and Fundamental Chemistry |
Wine, vinegar, cider, perry, brandy, atchara, nata de coco, burong mangga, asinan, pickling, vişinată, chocolate, rakı, aragh sagi, chacha | 1 | Applied and Interdisciplinary Chemistry |
The thermic effect of food is increased by both aerobic training of sufficient duration and intensity or by anaerobic weight training. However, the increase is marginal, amounting to 7-8 calories per hour. The primary determinants of daily TEF are the total caloric content of the meals and the macronutrient composition of the meals ingested. Meal frequency has little to no effect on TEF; assuming total calorie intake for the days are equivalent.
Although some believe that TEF is reduced in obesity, discrepant results and inconsistent research methods have failed to validate such claims.
The mechanism of TEF is unknown. TEF has been described as the energy used in the distribution of nutrients and metabolic processes in the liver, but a hepatectomized animal shows no signs of TEF and intravenous injection of amino acids results in an effect equal to that of oral ingestion of the same amino acids. | 1 | Applied and Interdisciplinary Chemistry |
An RA plot, like its cousin, the MA plot, is a re-scaled and (45-degree) rotated version of a simple two-dimensional scatter plot of a versus b where a and b are equal-length vectors of positive measurements. This rescaling and rotation allows for better visibility and emphasis of important outliers points that vary between the two measurement conditions. Essentially it is a plot of the log ratio [R] vs the average log [A] of each pairing of the elements of a and b. Unlike an MA plot, however, because the RA plot takes non-negative integer counts as input, it must employ work-arounds to include mathematically invisible points (such as points where one or both element(s) of the pair is zero).
If we modify our original a (or b) vector via:
where
then R and A can be defined as:
R, like M, is plotted on the y-axis and represents a log (fold change) ratio between a and b. A is plotted on the x-axis and represents the average abundance for a coordinate pair. The RA plot provides a quick overview of the distribution and size of a dataset consisting of non-zero counts. | 1 | Applied and Interdisciplinary Chemistry |
A metal carbido complex is a coordination complex that contains a carbon atom as a ligand. They are analogous to metal nitrido complexes. Carbido complexes are a molecular subclass of carbides, which are prevalent in organometallic and inorganic chemistry. Carbido complexes represent models for intermediates in Fischer–Tropsch synthesis, olefin metathesis, and related catalytic industrial processes. Ruthenium-based carbido complexes are by far the most synthesized and characterized to date. Although, complexes containing chromium, gold, iron, nickel, molybdenum, osmium, rhenium, and tungsten cores are also known. Mixed-metal carbides are also known. | 0 | Theoretical and Fundamental Chemistry |
MEGAN analysis starts with collecting reads from any shotgun platform. Then, the reads are compared with sequence databases using BLAST or similar. Third, MEGAN assigns a taxon ID to processed read results based on NCBI taxonomy which creates a MEGAN file that contains required information for statistical and graphical analysis. Lastly, lowest common ancestor (LCA) algorithm can be run to inspect assignments, to analyze data and to create summaries of data based on different NCBI taxonomy levels. LCA algorithm simply finds the lowest common ancestor of different species. | 1 | Applied and Interdisciplinary Chemistry |
A simple wave is a flow in a region adjacent to a region of constant state. In the language of Riemann invariant, the simple wave can also be defined as the zone where one of the Riemann invariant is constant in the region of interest, and consequently, a simple wave zone is covered by arcs of characteristics that are straight lines.
Simple waves occur quite often in nature. There is a theorem (see Courant and Friedrichs) that states that a non-constant state of flow adjacent to a constant value is always a simple wave. All expansion fans including Prandtl–Meyer expansion fan are simple waves. Compressive waves until shock wave forms are also simple waves. Weak shocks (including sound waves) are also simple waves up to second-order approximation in the shock strength.
Simple waves are also defined by the behavior that all the characteristics under hodograph transformation collapses into a single curve. This means that the Jacobian involved in the hodographic transformation is zero. | 1 | Applied and Interdisciplinary Chemistry |
The STRENDA Guidelines propose those minimum information that is needed to comprehensively report kinetic and equilibrium data from investigations of enzyme activities including corresponding experimental conditions.
This minimum information is suggested to be addressed in a scientific publication when enzymology research data is reported to ensure that data sets are comprehensively described. This allows scientists not only to review, interpret and corroborate the data but also to reuse the data for modelling and simulation of biocatalytic pathways. In addition, the guidelines support researchers making their experimental data reproducible and transparent.
As of March 2020, more than 55 international biochemistry journal included the STRENDA Guidelines in their authors' instructions as recommendations when reporting enzymology data.
The STRENDA project is registered with FAIRsharing.org and the Guidelines are part of the FAIRDOM Community standards for Systems Biology. | 1 | Applied and Interdisciplinary Chemistry |
In November 2020 several pharmaceutical companies announced successful trials of COVID-19 vaccines, with efficacy
of 90 to 95% in preventing infection. Per company announcements and data reviewed by external analysts, these vaccines are priced at $3 to $37 per dose. The Wall Street Journal ran an editorial calling for this achievement to be recognized with a Nobel Peace Prize.
Doctors Without Borders warned that high prices and monopolies on medicines, tests, and vaccines would prolong the pandemic and cost lives. They urged governments to prevent profiteering, using compulsory licenses as needed, as had already been done by Canada, Chile, Ecuador, Germany, and Israel.
On 20 February, 46 US lawmakers called for the US government not to grant monopoly rights when giving out taxpayer development money for any coronavirus vaccines and treatments, to avoid giving exclusive control of prices and availability to private manufacturers.
In the United States the government signed agreements in which research and development and/or the building of manufacturing plants for potential COVID-19 therapeutics was subsidized. Typically, the agreement involved the government taking ownership of a certain number of doses of the product without further payment. For example, under the auspices of Operation Warp Speed in the United States, the government subsidized research related to COVID-19 vaccines and therapeutics at Regeneron, Johnson and Johnson, Moderna, AstraZeneca, Novavax, Pfizer, and GSK. Typical terms involved research subsidies of $400 million to $2 billion, and included government ownership of the first 100 million doses of any COVID-19 vaccine successfully developed.
American pharmaceutical company Gilead sought and obtained orphan drug status for remdesivir from the US Food and Drug Administration (FDA) on 23 March 2020. This provision is intended to encourage the development of drugs affecting fewer than 200,000 Americans by granting strengthened and extended legal monopoly rights to the manufacturer, along with waivers on taxes and government fees. Remdesivir is a candidate for treating COVID-19; at the time the status was granted, fewer than 200,000 Americans had COVID-19, but numbers were climbing rapidly as the COVID-19 pandemic reached the US, and crossing the threshold soon was considered inevitable. Remdesivir was developed by Gilead with over $79 million in U.S. government funding. In May 2020, Gilead announced that it would provide the first 940,000 doses of remdesivir to the federal government free of charge. After facing strong public reactions, Gilead gave up the "orphan drug" status for remdesivir on 25 March. Gilead retains 20-year remdesivir patents in more than 70 countries. In May 2020, the company further announced that it was in discussions with several generics companies to provide rights to produce remdesivir for developing countries, and with the Medicines Patent Pool to provide broader generic access. | 1 | Applied and Interdisciplinary Chemistry |
Of 744 apples tested USDA found 82.7% of them to have diphenylamine residue between 0.005 - 4.3 ppm, below the U.S. EPA's tolerance level of 10ppm.
A number of alternatives to the use of diphenylamine exist for the control of scald of apples. | 0 | Theoretical and Fundamental Chemistry |
With the help of the Lifshitz Theory on Casimir, respectively van der Waals, interactions of macroscopic bodies premelting can be viewed from an electrodynamical perspective.
A good example for determining the difference between complete and incomplete premelting is ice. From vacuum ultraviolet (VUV) frequencies upwards the polarizability of ice is greater than that of water, at lower frequencies this is reversed. Assuming there is already a film of thickness on the solid it is easy for any components of electromagnetic waves to travel through the film in the direction perpendicular to the solid surface as long is small. Hence as long as the film is thin compared to the frequency interaction from the solid to the whole film is possible. But when gets large compared to typical VUV frequencies the electronic structure of the film will be too slow to pass the high frequencies to the other end of the liquid phase. Thus this end of the liquid phase feels only a retarded van der Waals interaction with the solid phase. Hence the attraction between the liquid molecules themselves will predominate and they will start forming droplets instead of thickening the film further. So the speed of light limits complete premelting. This makes it a question of solid and surface free energies whether complete premelting occurs. Complete surface melting will occur when is monotonically decreasing. If instead shows a global minimum at finite than the premelting will be incomplete. This implies: When the long range interactions in the system are attractive than there will be incomplete premelting — assuming the film thickness is larger than any repulsive interactions. Is the film thickness small compared to the range of the repulsive interactions present and the repulsive interactions are stronger than the attractive ones than complete premelting can occur.
For van der Waals interactions Lifshitz theory can now calculate which type of premelting should occur for a special system. In fact small differences in systems can affect the type of premelting. For example, ice in an atmosphere of water vapour shows incomplete premelting, whereas the premelting of ice in air is complete.
For solid–solid interfaces it cannot be predicted in general whether the premelting is complete or incomplete when only considering van der Waals interactions. Here other types of interactions become very important. This also accounts for grain boundaries. | 0 | Theoretical and Fundamental Chemistry |
The magic-angle-turning (MAT) technique introduced by Gan employs slow (approximately 30 Hz) rotation of a powdered sample at the magic angle, in concert with pulses synchronized to 1/3 of the rotor period, to obtain isotropic-shift information in one dimension of a 2D spectrum. | 0 | Theoretical and Fundamental Chemistry |
With respects to archaeological applications, in the mid-1980s, Joseph Davidovits presented his first analytical results carried out on genuine pyramid stones. He claimed that the ancient Egyptians knew how to generate a geopolymeric reaction in the making of a re-agglomerated limestone blocks. The Ukrainian scientist G.V. Glukhovsky endorsed Davidovits' research in his keynote paper to the First Intern. Conf. on Alkaline Cements and Concretes, Kiev, Ukraine, 1994. Later on, several materials scientists and physicists took over these archaeological studies and are publishing their results, essentially on pyramid stones. | 0 | Theoretical and Fundamental Chemistry |
Fungi can cause microbial corrosion of concrete. With adequate environmental factors, such as humidity, temperature, and organic carbon sources, fungi will produce colonies on concrete. Some fungi can reproduce asexually. This common process among fungi allows many new fungal spores to quickly spread to new environments, developing entire colonies where nothing existed. These colonies and the new spores produced use hyphae to absorb environmental nutrients.
Hyphae are incredibly tiny and thin, growing only 2 to 6 micrometers in diameter. Fungal hyphae are used to reach deep into minuscule holes, cracks, and ravines in concrete. These areas contain moisture and nutrients the fungus survives on. As more hyphae force their way into these tiny cracks and crevices, the pressure causes those gaps to expand, similar to how water freezes in tiny holes and cracks, causing them to widen. The mechanical pressure enables cracks to expand, leading to more moisture getting inside, and thus, the fungi have more nutrients, allowing them to travel deeper into the concrete structure. By altering their environment, fungi break down concrete and its alkaline layer, thus providing ideal conditions for corrosion-causing bacteria to further degrade concrete structures.
Another way fungi cause corrosion on concrete is through organic acids naturally produced by the fungi. These organic acids chemically react with Calcium 2+ in the concrete which produces water-soluble salts as a product. The Calcium 2+ is then released, causing extensive damage over time to the structure. Due to the fact that fungi expel digestive juices to gain nutrients, the structure they grow on will begin to dissolve. This is no different for concrete when fungi such as Fusarium take root. An experiment compared the corrosion of the bacteria Tiobacillus to the corrosion of a fungus called Fusarium. In the experiment, both groups of organisms were provided with adequate conditions to grow, along with an equal piece of concrete in each experiment. After 147 days, the Tiobacillus bacterium caused an 18% mass reduction. However, the Fusarium fungus caused a 24% mass reduction in the same time frame, thus showcasing its corrosive abilities.
Bhattacharyya did a study on the three separate types of fungi that are known to cause concrete corrosion: Aspergillus tamarii, Aspergillus niger, and Fusarium. Aspergillus tamarii was the most destructive of the three fungi. It causes cracks to widen and deepen, quickly and efficiently takes root, and promotes calcium oxalate. By causing calcium oxalate, there is an increase in the speed of calcium ion leaching, which lowers the overall strength of concrete. In 90 days, exposure to the fungus resulted in a mass reduction of 7.2% in the concrete. Aspergillus niger was the second worst offender out of the three, followed by Fusarium, which can lower the mass of concrete by 6.2 grams in a single year, as well as cause the pH to down from 12 to 8 in the same time frame. | 1 | Applied and Interdisciplinary Chemistry |
The discretized equations are solved numerically on a staggered grid, i.e. the scalar quantities , and are defined at the cell centre while the velocity components , and are defined at the centre of the appropriate interfaces.
Temporal discretization of the prognostic equations is based on the explicit second order Adams-Bashforth scheme. There are two deviations from the Adams-Bashforth scheme: The first refers to the implicit treatment of the nonhydrostatic part of the mesoscale pressure perturbation . To ensure non-divergence of the flow field, an elliptic equation is solved. The elliptic equation is derived from the continuity equation wherein velocity components are expressed in terms of . Since the elliptic equation is derived from the discrete form of the continuity equation and the discrete form of the pressure gradient, conservativity is guaranteed (Flassak and Moussiopoulos, 1988). The discrete pressure equation is solved numerically with a fast elliptic solver in conjunction with a generalized conjugate gradient method. The fast elliptic solver is based on fast Fourier analysis in both horizontal directions and Gaussian elimination in the vertical direction (Moussiopoulos and Flassak, 1989).
The second deviation from the explicit treatment is related to the turbulent diffusion in vertical direction. In case of an explicit treatment of this term, the stability requirement may necessitate an unacceptable abridgement of the time increment. To avoid this, vertical turbulent diffusion is treated using the second order Crank–Nicolson method.
On principle, advective terms can be computed using any suitable advection scheme. In the present version of MEMO, a 3D second-order total-variation-diminishing (TVD) scheme is implemented which is based on the 1D scheme proposed by Harten (1986). It achieves a fair (but not any) reduction of numerical diffusion, the solution being independent of the magnitude of the scalar (preserving transportivity). | 1 | Applied and Interdisciplinary Chemistry |
Cast bronzes are known to have been produced in Africa by the 9th century AD in Igboland (Igbo-Ukwu) in Nigeria, the 12th century AD in Yorubaland (Ife) and the 15th century AD in the kingdom of Benin. Some portrait heads remain.
Benin mastered bronze during the 16th century, produced portraiture and reliefs in the metal using the lost wax process. | 1 | Applied and Interdisciplinary Chemistry |
Analytical band centrifugation (ABC) (also known as analytical band ultracentrifugation, or band sedimentation-velocity), is a specialized ultracentrifugation procedure, where unlike the typical use of (boundary) sedimentation velocity analytical ultracentrifugation (SV-AUC) wherein a homogenous bulk solution is centrifuged, in ABC a thin (~15 µL, ~500 µm) sample is layered on top of a bulk solvent and then centrifuged. The method is distinguished from zone-sedimentation in that a stabilizing density gradient is self-generated during centrifugation, through the use of a higher density (than the sample) bulk "binary solvent", containing both a solvent (i.e. HO), and a second component (small molecules, i.e. CsCl) that will sediment to form a stabilizing density gradient for the sample.
ABC also requires specially designed analytical ultracentrifuge cells, as the sample is not manually applied by pipette but instead automatically delivered via capillary under low g-forces at the beginning of a run from a reservoir within the cell. It was first demonstrated in 1963, and was not commonly used for many decades, but recently has become more widely used due to its applicability to quality control measurements on therapeutic viruses such as adeno-associated viruses (AAVs). The profiles resulting from ABC analyses are similar in their interpretation to the profiles from electrophoretic separations ("electropherograms"), and thus have been dubbed "centrifugrams". | 1 | Applied and Interdisciplinary Chemistry |
Microwaves impinging on matter usually interact with charges as well as with spins (via electric and magnetic field components, respectively), with the charge response typically much stronger than the spin response. But in the case of magnetic resonance, spins can be directly probed using microwaves. For paramagnetic materials, this technique is called electron spin resonance (ESR) and for ferromagnetic materials ferromagnetic resonance (FMR).
In the paramagnetic case, such an experiment probes the Zeeman splitting, with a linear relation between the static external magnetic field and the frequency of the probing microwave field. A popular combination, as implemented in commercial X-band ESR spectrometers, is approximately 0.3 T (static field) and 10 GHz (microwave frequency) for a typical material with electron g-factor close to 2. | 0 | Theoretical and Fundamental Chemistry |
The reaction is fueled with deuterium, a widely available non-radioactive hydrogen isotope composed of one proton, one neutron, and one electron. The deuterium is confined in the space between the atoms of a metal solid such as erbium or titanium. Erbium can indefinitely maintain 10 cm deuterium atoms (deuterons) at room temperature. The deuteron-saturated metal forms an overall neutral plasma. The electron density of the metal reduces the likelihood that two deuterium nuclei will repel each other as they get closer together.
A dynamitron electron-beam accelerator generates an electron beam that hits a tantalum target and produces gamma rays, irradiating titanium deuteride or erbium deuteride. A gamma ray of about 2.2 megaelectron volts (MeV) strikes a deuteron and splits it into proton and neutron. The neutron collides with another deuteron. This second, energetic deuteron can experience screened fusion or a stripping reaction.
Although the lattice is notionally at room temperature, LCF creates an energetic environment inside the lattice where individual atoms achieve fusion-level energies. Heated regions are created at the micrometer scale. | 0 | Theoretical and Fundamental Chemistry |
A flame test involves introducing a sample of the element or compound to a hot, non-luminous flame and observing the color of the flame that results. The compound can be made into a paste with concentrated hydrochloric acid, as metal halides, being volatile, give better results. Different flames can be tried to verify the accuracy of the color. Wooden splints, Nichrome wires, cotton swabs, and melamine foam are suggested for support. Safety precautions are crucial due to the flammability and toxicity of some substances involved. When using a splint, one must be careful to wave the splint through the flame rather than holding it in the flame for extended periods, to avoid setting the splint itself on fire. The use of a cotton swab or melamine foam (used in “eraser” cleaning sponges) as a support has also been suggested. Sodium is a common component or contaminant in many samples, and its spectrum tends to dominate many flame tests others. The test flame is often viewed through cobalt blue glass to filter out the yellow of sodium and allow for easier viewing of other metal ions.
The color of the flames also generally depends on temperature and oxygen fed; see flame colors. The procedure uses different solvents and flames to view the test flame through a cobalt blue glass to filter the interfering light of contaminants such as sodium.
Flame tests are subject of a number of limitations. The range of elements positively detectable under standard conditions is small. Some elements emit weakly and others (Na) very strongly. Gold, silver, platinum, palladium, and a number of other elements do not produce a characteristic flame color, although some may produce sparks (as do metallic titanium and iron); salts of beryllium and gold reportedly deposit pure metal on cooling. The test is highly subjective. | 1 | Applied and Interdisciplinary Chemistry |
The austrapede (Tspìng in Navi) is a Pandoran creature that resembles a cross between an ostrich, a pink flamingo and the herbivorous dinosaur Parasaurolophus. The Austrapede has yellow-orange skin with faint purple striping, a long, flat beak, and a flat tail reaching down to its feet. Unlike other Pandoran birds and its relative, the great austrapede, the austrapedes wings have shrunken down to small, vestigial appendages, and much of its height is made up by its legs and neck. Austrapedes flap their wings when frightened. The austrapedes are impulsive, fidgety creatures whose emotions spread quickly from one individual to the other by a form of mimicry. Relatively small by Pandoran standards, Austrapedes generally pose little threat to other creatures, and are sometimes affectionate to Navi. They first appear in the musical, Toruk – The First Flight'. | 1 | Applied and Interdisciplinary Chemistry |
The safety and efficacy of piflufolastat F-18 were evaluated in two prospective clinical trials (trial 1/NCT02981368 and trial 2/NCT03739684) with a total of 593 men with prostate cancer who each received one injection of piflufolastat F-18. In the first trial, a cohort of 268 participants with biopsy-proven prostate cancer underwent PET/CT scans performed with piflufolastat F-18. These participants were candidates for surgical removal of the prostate gland and pelvic lymph nodes and were considered at higher risk for metastasis. Among the participants who proceeded to surgery, those with positive readings in the pelvic lymph nodes on piflufolastat F-18 PET had a clinically important rate of metastatic cancer confirmed by surgical pathology.
The second trial enrolled 208 participants who had rising serum prostate-specific antigen levels after initial prostate surgery or other definitive therapy, and thus had biochemical evidence of recurrent prostate cancer. Prior to a single piflufolastat F-18 PET/CT scan, all of these participants had baseline conventional imaging performed that did not show definite spread of prostate cancer. Piflufolastat F-18 PET detected at least one positive lesion in at least one body region (bone, prostate bed, pelvic lymph node, other lymph nodes, or soft tissue) in 60% of these participants. In participants with positive piflufolastat F-18 PET readings who had correlative tissue pathology from biopsies, results from baseline or follow-up imaging by conventional methods, or serial PSA levels available for comparison, local recurrence or metastasis of prostate cancer was confirmed in an estimated 85% to 87% of cases, depending on the reader. Thus, the second trial demonstrated that piflufolastat F-18 PET can detect sites of disease in participants with biochemical evidence of recurrent prostate cancer, thereby providing important information that may impact the approach to therapy.
Trial 1 included two groups of participants, some with recently diagnosed prostate cancer and others with suspicious findings on standard tests. Trial 2 included participants who were treated for prostate cancer before, but there was suspicion that the cancer was spreading because of rising prostate-specific antigen. Participants in trial 2 and the recently diagnosed participants in trial 1 were studied for effectiveness of piflufolastat F-18, and all participants were studied for safety. Trial 1 was conducted at eight sites in the United States and two sites in Canada, and trial 2 was conducted at thirteen sites in the United States and one site in Canada. The number of participants representing efficacy findings may differ from the number of participants representing safety findings due to different pools of study participants analyzed for efficacy and safety.
The US Food and Drug Administration (FDA) granted approval of Pylarify to Progenics Pharmaceuticals, Inc. | 1 | Applied and Interdisciplinary Chemistry |
Signal transducer and activator of transcription 5 (STAT5) refers to two highly related proteins, STAT5A and STAT5B, which are part of the seven-membered STAT family of proteins. Though STAT5A and STAT5B are encoded by separate genes, the proteins are 90% identical at the amino acid level. STAT5 proteins are involved in cytosolic signalling and in mediating the expression of specific genes. Aberrant STAT5 activity has been shown to be closely connected to a wide range of human cancers, and silencing this aberrant activity is an area of active research in medicinal chemistry. | 1 | Applied and Interdisciplinary Chemistry |
Supplemental HMB has been used in clinical trials as a treatment for preserving lean body mass in muscle wasting conditions, particularly sarcopenia, and has been studied in clinical trials as an adjunct therapy in conjunction with resistance exercise. Based upon two medical reviews and a meta-analysis of seven randomized controlled trials, HMB supplementation can preserve or increase lean muscle mass and muscle strength in sarcopenic older adults. HMB does not appear to significantly affect fat mass in older adults. Preliminary clinical evidence suggests that HMB supplementation may also prevent muscle atrophy during bed rest. A growing body of evidence supports the efficacy of HMB in nutritional support for reducing, or even reversing, the loss of muscle mass, muscle function, and muscle strength that occurs in hypercatabolic disease states such as cancer cachexia; consequently, the authors of two 2016 reviews of the clinical evidence recommended that the prevention and treatment of sarcopenia and muscle wasting in general include supplementation with HMB, regular resistance exercise, and consumption of a high-protein diet.
Clinical trials that used HMB for the treatment of muscle wasting have involved the administration of 3 grams of HMB per day under different dosing regimens. According to one review, an optimal dosing regimen is to administer it in one 1 gram dose, three times a day, since this ensures elevated plasma concentrations of HMB throughout the day; however, the best dosing regimen for muscle wasting conditions is still being investigated.
Some branded products that contain HMB (i.e., certain formulations of Ensure and Juven) are medical foods that are intended to be used to provide nutritional support under the care of a doctor in individuals with muscle wasting due to HIV/AIDS or cancer, to promote wound healing following surgery or injury, or when otherwise recommended by a medical professional. Juven, a nutrition product which contains 3 grams of , 14 grams of -arginine, and 14 grams of -glutamine per two servings, has been shown to improve lean body mass during clinical trials in individuals with AIDS and cancer, but not rheumatoid cachexia. Further research involving the treatment of cancer cachexia with Juven over a period of several months is required to adequately determine treatment efficacy. | 1 | Applied and Interdisciplinary Chemistry |
This salt is prepared by treating an aqueous solution of ruthenium trichloride with 2,2'-bipyridine. In this conversion, Ru(III) is reduced to Ru(II), and hypophosphorous acid is typically added as a reducing agent. [Ru(bpy)] is octahedral, containing a central low spin d Ru(II) ion and three bidentate bpy ligands. The Ru-N distances are 2.053(2), shorter than the Ru-N distances for [Ru(bpy)]. The complex is chiral, with D symmetry. It has been resolved into its enantiomers. In its lowest lying triplet excited state the molecule is thought to attain lower C symmetry, as the excited electron is localized primarily on a single bipyridyl ligand. | 0 | Theoretical and Fundamental Chemistry |
To be defined as ferroelectric, a material must have a spontaneous electric polarization that is switchable by an applied electric field. Usually such an electric polarization arises via an inversion-symmetry-breaking structural distortion from a parent centrosymmetric phase. For example, in the prototypical ferroelectric barium titanate, BaTiO, the parent phase is the ideal cubic ABO perovskite structure, with the B-site Ti ion at the center of its oxygen coordination octahedron and no electric polarisation. In the ferroelectric phase the Ti ion is shifted away from the center of the octahedron causing a polarization. Such a displacement only tends to be favourable when the B-site cation has an electron configuration with an empty d shell (a so-called d configuration), which favours energy-lowering covalent bond formation between the B-site cation and the neighbouring oxygen anions.
This "d0-ness" requirement is a clear obstacle for the formation of multiferroics, since the magnetism in most transition-metal oxides arises from the presence of partially filled transition metal d shells. As a result, in most multiferroics, the ferroelectricity has a different origin. The following describes the mechanisms that are known to circumvent this contraindication between ferromagnetism and ferroelectricity. | 0 | Theoretical and Fundamental Chemistry |
People or objects contaminated with CS gas can cause secondary exposure to others, including healthcare professionals and police. In addition, repeated exposure may cause sensitisation. | 1 | Applied and Interdisciplinary Chemistry |
The phenomenon in which organic luminophores show higher photoluminescence efficiency in the aggregated state than in solution is called aggregation-induced emission enhancement (AIEE). Some luminophores, e.g., diketopyrrolopyrrole-based and sulfonamide-based luminophores, only display enhanced emission upon entering the crystalline state. That is, these luminophores are said to exhibit crystallization-induced emission enhancement (CIEE).
Luminophores such as noble metallic nanoclusters show higher
photoluminescence efficiency in the aggregated state than homogenous
dispersion in solution. This phenomenon is known as
Aggregation-Induced Emission (AIE). | 0 | Theoretical and Fundamental Chemistry |
The software has been applied to simulate almost all engine applications and all transportation fuel combinations with many examples published in numerous leading peer-reviewed journals, a brief summary of these articles is presented here.
# Spark ignition combustion mode: Sub-models to simulate Direct Injection Spark Ignition engines for regular flame propagation events, PM and NOx exhaust gas emissions. Further analysis of knocking and irregular combustion events are facilitated through the implementation of user-defined or the chemical kinetic fuel models included with the tool.
# CIDI (diesel) combustion mode: Sub-models for direct injection, turbulence and chemical kinetic enable the simulation of diesel combustion and emission analysis. Typical user projects have included combustion, PM and NOx simulation over a load-speed map, virtual engine optimization, comparison with 3D-CFD and injection strategy optimization.
# Low temperature combustion mode: Known as HCCI or premixed CIDI combustion (PCCI, PPCI), ignition and flame propagation in low temperature combustion mode is more sensitive to fuel chemistry effects. By accounting for user defined or by applying the default chemical kinetic fuel models, users do benefit from enhanced predictive performance. Typical projects include identifying the operating and misfire limits for multiple fuel types.
# Advanced fuels: To date the model has been applied to conventional diesel, gasoline, blends of gasoline and diesel, bio-fuels, hydrogen, natural gas, and ethanol-blended gasoline fuel applications.
# Exhaust gas emissions: Through the implementation of detailed chemical kinetic in both the gas and solid particulate phases, all conventional automotive and non-road exhaust gas emissions are simulated in detail. | 1 | Applied and Interdisciplinary Chemistry |
The phenomenon was observed in 2008 by the Argentine Sebastian Bianchini during mate tea preparation, while studying physics at the University of Havana.
It rapidly attracted the interest of professor Alejandro Lage-Castellanos, who performed, with Bianchini, a series of controlled experiments. Later on professor Ernesto Altshuler completed the trio in Havana, which resulted in the Diploma thesis of Bianchini and a short original paper posted in the web arXiv and mentioned as a surprising fact in some online journals.
Bianchini's Diploma thesis showed that the phenomenon could be reproduced in a controlled laboratory setting using mate leaves or chalk powder as contaminants, and that temperature gradients (hot in the top, cold in the bottom) were not necessary to generate the effect. The research also showed that surface tension was key to the explanation through the Marangoni effect. This was suggested by two facts: (a) both mate and chalk lowered the surface tension of water, and (b) if an industrial surfactant was added on the upper reservoir, the upstream motion of particles would stop. | 1 | Applied and Interdisciplinary Chemistry |
A regulatory sequence is a segment of a nucleic acid molecule which is capable of increasing or decreasing the expression of specific genes within an organism. Regulation of gene expression is an essential feature of all living organisms and viruses. | 1 | Applied and Interdisciplinary Chemistry |
Some children conceived by IVF using anonymous donors report being troubled over not knowing about their donor parent as well any genetic relatives they may have and their family history.
Alana Stewart, who was conceived using donor sperm, began an online forum for donor children called AnonymousUS in 2010. The forum welcomes the viewpoints of anyone involved in the IVF process. Olivia Pratten, a donor-conceived Canadian, sued the province of British Columbia for access to records on her donor fathers identity in 2008. "Im not a treatment, Im a person, and those records belong to me," Pratten said. In May 2012, a court ruled in Prattens favour, agreeing that the laws at the time discriminated against donor children and making anonymous sperm and egg donation in British Columbia illegal.
In the U.K., Sweden, Norway, Germany, Italy, New Zealand, and some Australian states, donors are not paid and cannot be anonymous.
In 2000, a website called Donor Sibling Registry was created to help biological children with a common donor connect with each other.
In 2012, a documentary called Anonymous Fathers Day' was released that focuses on donor-conceived children. | 1 | Applied and Interdisciplinary Chemistry |
John William Draper was born May 5, 1811, in St. Helens, Lancashire, England, to John Christopher Draper, a Wesleyan clergyman, and Sarah (Ripley) Draper. He also had three sisters, Dorothy Catherine Draper (August 6, 1807 – December 10, 1901), Elizabeth Johnson, and Sarah Ripley. On June 23, he was baptized by the Wesleyan Methodist minister Jabez Bunting. His father often needed to move the family due to serving various congregations throughout England. John Wm. Draper was home tutored until 1822, when he entered Woodhouse Grove School. He returned to home instruction (1826) prior to entering University College London in 1829. While at University College London, Draper studied chemistry under the direction of Edward Turner (chemist).
On September 13, 1831, John William Draper married Antonia Caetana de Paiva Pereira Gardner (–1870), the daughter of Daniel Gardner, a court physician to John VI of Portugal and Charlotte of Spain. Antonia was born in Brazil after the royal family fled Portugal with Napoleons invasion. There is dispute as to the identity of Antonias mother. Around 1830, Antonia was sent with her brother Daniel to live with their aunt in London.
Following his fathers death in July 1831, John Williams mother was urged to move with her children to the US state of Virginia. John William hoped to acquire a teaching position at a local Methodist college. | 0 | Theoretical and Fundamental Chemistry |
In a 1925 paper, F.H. Constable described the linear relationship observed for the reaction parameters of the catalytic dehydrogenation of primary alcohols with copper-chromium oxide. | 0 | Theoretical and Fundamental Chemistry |
Gene structure is the organisation of specialised sequence elements within a gene. Genes contain most of the information necessary for living cells to survive and reproduce. In most organisms, genes are made of DNA, where the particular DNA sequence determines the function of the gene. A gene is transcribed (copied) from DNA into RNA, which can either be non-coding (ncRNA) with a direct function, or an intermediate messenger (mRNA) that is then translated into protein. Each of these steps is controlled by specific sequence elements, or regions, within the gene. Every gene, therefore, requires multiple sequence elements to be functional. This includes the sequence that actually encodes the functional protein or ncRNA, as well as multiple regulatory sequence regions. These regions may be as short as a few base pairs, up to many thousands of base pairs long.
Much of gene structure is broadly similar between eukaryotes and prokaryotes. These common elements largely result from the shared ancestry of cellular life in organisms over 2 billion years ago. Key differences in gene structure between eukaryotes and prokaryotes reflect their divergent transcription and translation machinery. Understanding gene structure is the foundation of understanding gene annotation, expression, and function. | 1 | Applied and Interdisciplinary Chemistry |
The Sanford–Wang parameterisation is an empirical formula used to model the production of pions in nuclear interaction of the form p+A → +X where a beam of high-energy protons hit a material.
Its formula for the double-differential cross section with respect to momentum (p) and solid angle () is as follows.
Where p and are the momentum of the outgoing pion and its angle from the direction of the incident proton. The numbers are the Sanford-Wang parameters and are typically varied to give a good fit with experimental data. | 0 | Theoretical and Fundamental Chemistry |
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers.
An eddy is a movement of fluid that deviates from the general flow of the fluid. An example for an eddy is a vortex which produces such deviation. However, there are other types of eddies that are not simple vortices. For example, a Rossby wave is an eddy which is an undulation that is a deviation from mean flow, but does not have the local closed streamlines of a vortex. | 1 | Applied and Interdisciplinary Chemistry |
Mathews was raised on a dairy farm near the unincorporated community of Auroraville, Wisconsin in Waushara County, Wisconsin. As a youth, he had little interest in farm life or in the cheese factory operated by his older brother. His parents sent Joseph to public school in nearby Berlin, a city that straddles the boundary between Waushara and Green Lake counties. He graduated from Omro High School (Omro, Winnebago County). Mathews studied briefly at Ripon College in Ripon, Wisconsin, and then transferred to the University of Wisconsin. Mathews earned the B.S. in chemistry in 1903, writing a senior thesis on nitrosyl selenic acid, based on research under the supervision of Victor Lenher (1873–1927). | 0 | Theoretical and Fundamental Chemistry |
A plasmid preparation is a method of DNA extraction and purification for plasmid DNA, it is an important step in many molecular biology experiments and is essential for the successful use of plasmids in research and biotechnology. Many methods have been developed to purify plasmid DNA from bacteria. During the purification procedure, the plasmid DNA is often separated from contaminating proteins and genomic DNA.
These methods invariably involve three steps: growth of the bacterial culture, harvesting and lysis of the bacteria, and purification of the plasmid DNA. Purification of plasmids is central to molecular cloning. A purified plasmid can be used for many standard applications, such as sequencing and transfections into cells. | 1 | Applied and Interdisciplinary Chemistry |
The term is known as the pairing term (possibly also known as the pairwise interaction). This term captures the effect of spin coupling. It is given by
where is found empirically to have a value of about 1000 keV, slowly decreasing with mass number A. The binding energy may be increased by converting one of the odd protons or neutrons into a neutron or proton, so the odd nucleon can form a pair with its odd neighbour forming and even Z, N. The pair have overlapping wave functions and sit very close together with a bond stronger than any other configuration. When the pairing term is substituted into the binding energy equation, for even Z, N, the pairing term adds binding energy, and for odd Z, N the pairing term removes binding energy.
The dependence on mass number is commonly parametrized as
The value of the exponent k is determined from experimental binding-energy data. In the past its value was often assumed to be −3/4, but modern experimental data indicate that a value of −1/2 is nearer the mark:
: or
Due to the Pauli exclusion principle the nucleus would have a lower energy if the number of protons with spin up were equal to the number of protons with spin down. This is also true for neutrons. Only if both Z and N are even, can both protons and neutrons have equal numbers of spin-up and spin-down particles. This is a similar effect to the asymmetry term.
The factor is not easily explained theoretically. The Fermi-ball calculation we have used above, based on the liquid-drop model but neglecting interactions, will give an dependence, as in the asymmetry term. This means that the actual effect for large nuclei will be larger than expected by that model. This should be explained by the interactions between nucleons. For example, in the shell model, two protons with the same quantum numbers (other than spin) will have completely overlapping wavefunctions and will thus have greater strong interaction between them and stronger binding energy. This makes it energetically favourable (i.e. having lower energy) for protons to form pairs of opposite spin. The same is true for neutrons. | 0 | Theoretical and Fundamental Chemistry |
The development of the APCI interface for LC–MS started with Horning and collaborators in the early 1973. However, its commercial application was introduced at the beginning of the 1990s after Henion and collaborators improved the LC–APCI–MS interface in 1986. The APCI ion source/ interface can be used to analyze small, neutral, relatively non-polar, and thermally stable molecules (e.g., steroids, lipids, and fat soluble vitamins). These compounds are not well ionized using ESI. In addition, APCI can also handle mobile phase streams containing buffering agents. The liquid from the LC system is pumped through a capillary and there is also nebulization at the tip, where a corona discharge takes place. First, the ionizing gas surrounding the interface and the mobile phase solvent are subject to chemical ionization at the ion source. Later, these ions react with the analyte and transfer their charge. The sample ions then pass through small orifice skimmers by means of or ion-focusing lenses. Once inside the high vacuum region, the ions are subject to mass analysis. This interface can be operated in positive and negative charge modes and singly-charged ions are mainly produced. APCI ion source can also handle flow rates between 500 and 2000 μl/min and it can be directly connected to conventional 4.6 mm ID columns. | 0 | Theoretical and Fundamental Chemistry |
In addition to converters using electrodes, pure inductive magnetic converters have also been proposed by Lev Artsimovich in 1963, then Alan Frederic Haught and his team from United Aircraft Research Laboratories in 1970, and Ralph Moir in 1977.
The magnetic compression-expansion direct energy converter is analogous to the internal combustion engine. As the hot plasma expands against a magnetic field, in a manner similar to hot gases expanding against a piston, part of the energy of the internal plasma is inductively converted to an electromagnetic coil, as an EMF (voltage) in the conductor.
This scheme is best used with pulsed devices, because the converter then works like a "magnetic four-stroke engine":
# Compression: A column of plasma is compressed by a magnetic field that acts like a piston.
# Thermonuclear burn: The compression heats the plasma to the thermonuclear ignition temperature.
# Expansion/Power: The expansion of fusion reaction products (charged particles) increases the plasma pressure and pushes the magnetic field outward. A voltage is induced and collected in the electromagnetic coil.
# Exhaust/Refuel: After expansion, the partially burned fuel is flushed out, and new fuel in the form of gas is introduced and ionized; and the cycle starts again.
In 1973, a team from Los Alamos and Argonne laboratories stated that the thermodynamic efficiency of the magnetic direct conversion cycle from alpha-particle energy to work is 62%. | 0 | Theoretical and Fundamental Chemistry |
The major tissue systems present are
* The epidermis, which covers the upper and lower surfaces
* The mesophyll tissue, which consists of photosynthetic cells rich in chloroplasts. (also called chlorenchyma)
* The arrangement of veins (the vascular tissue)
These three tissue systems typically form a regular organization at the cellular scale. Specialized cells that differ markedly from surrounding cells, and which often synthesize specialized products such as crystals, are termed idioblasts. | 0 | Theoretical and Fundamental Chemistry |
Feather meal is a byproduct of processing poultry; it is made from poultry feathers by partially grinding them under elevated heat and pressure, and then grinding and drying. Although total nitrogen levels are fairly high (up to 12%), the bioavailability of this nitrogen may be low. Feather meal is used in formulated animal feed and in organic fertilizer.
Worldwide, approximately 50 billion chickens were used for human consumption in 2014. Feather meal is made through a process called rendering. Steam pressure cookers with temperatures over are used to "cook" and sterilize the feathers. This partially hydrolyzes the proteins, which denatures them. It is then dried, cooled and ground into a powder for use as a nitrogen source for animal feed (mostly ruminants) or as an organic soil amendment.
Containing up to 12% nitrogen, it is a source of slow-release, organic, high-nitrogen fertilizer for organic gardens. It is not water-soluble and does not make a good liquid fertilizer. It can be used to:
*Increase green leaf growth
*Activate compost decomposition
*Improve soil structure
When adding it to a garden as a nitrogen source, it must be blended into the soil to start the decomposition to make the nitrogenous compounds available to the plants. As an organic garden fertilizer, it is not synthetic or petroleum-based. | 0 | Theoretical and Fundamental Chemistry |
Utilization of halogen containing materials in processes such as water treatment, bleaching, or even general synthesis to create the final product, generates a number of organic halides. These organic halides are released in wastewater from the oil, chemical, and paper industries, and find their way to the consumer and eventually to a landfill or oceanic dumps. Within the soil, the halo compounds resist degradation and often react with metal ions, resulting in non-degradable metal complexes, increasing soil toxicity and accumulating in the food chain of aquatic organisms. Up to 2000 ppm of these bio-accumulative organic chlorides were detected in fat of fish from the waters where bleaching effluents were disposed by paper mills, where a 2% water concentration is considered toxic for the fish. While strict regulations from the government have reduced the high level of past emissions, these compounds find their way to water sources through improper consumer disposal of items that contain chlorinated compounds. The presence of any organic halides in natural water has been considered an indication of contamination with xenobiotics. Once in water, the naturally occurring fulvic acids and humic acids can lead to formation of mutagenic compounds such as halogenated furanone MX (Z-3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone). Consumption of these mutagenic compounds could cause several abnormalities in development and reproduction in humans through long half-lives and mimicking hormone receptors. For example, compounds like dioxins can inhibit the actions of sex hormones by binding to steroid receptors along with causing long lasting cell disruption in several tissues. | 1 | Applied and Interdisciplinary Chemistry |
Although traditionally thought to form at compositions XYZ and XYZ, studies published after 2015 have discovered and reliably predicted Heusler compounds with atypical compositions such as XYZ and XYZ. Besides these ternary compositions, quaternary Heusler compositions called the double Half-Heusler XYYZ (e.g. TiFeNiSb) and triple Half-Heusler XXYZ (for e.g. MgVNiSb) have also been discovered. These "off-stoichiometric" (that is, differing from the well-known XYZ and XYZ compositions) Heuslers are mostly semiconductors in the low temperature T = 0 K limit. The stable compositions and corresponding electrical properties for these compounds can be quite sensitive to temperature and their order-disorder transition temperatures often occur below room-temperatures. Large amounts of defects at the atomic scale in off-stoichiometric Heuslers helps them achieve very low thermal conductivities and make them favorable for thermoelectric applications. The XYZ semiconducting composition is stabilized by the transition metal X playing a dual role (electron donor as well as acceptor) in the structure. | 1 | Applied and Interdisciplinary Chemistry |
The cleaved amplified polymorphic sequence (CAPS) method is a technique in molecular biology for the analysis of genetic markers. It is an extension to the restriction fragment length polymorphism (RFLP) method, using polymerase chain reaction (PCR) to more quickly analyse the results.
Like RFLP, CAPS works on the principle that genetic differences between individuals can create or abolish restriction endonuclease restriction sites, and that these differences can be detected in the resulting DNA fragment length after digestion.
In the CAPS method, PCR amplification is directed across the altered restriction site, and the products digested with the restriction enzyme. When fractionated by agarose or polyacrylamide gel electrophoresis, the digested PCR products will give readily distinguishable patterns of bands. Alternatively, the amplified segment can be analyzed by allele-specific oligonucleotide (ASO) probes, a process that can often be done by a simple dot blot. | 1 | Applied and Interdisciplinary Chemistry |
As the alveoli increase in size, the surfactant becomes more spread out over the surface of the liquid. This increases surface tension effectively slowing the rate of expansion of the alveoli. This also helps all alveoli in the lungs expand at the same rate, as one that expands more quickly will experience a large rise in surface tension slowing its rate of expansion. It also means the rate of shrinking is more regular as if one reduces in size more quickly the surface tension will reduce more, so other alveoli can contract more easily than it can. Surfactant reduces surface tension more readily when the alveoli are smaller because the surfactant is more concentrated. | 0 | Theoretical and Fundamental Chemistry |
Phenol red is a weak estrogen mimic, and in cell cultures can enhance the growth of cells that express the estrogen receptor. It has been used to induce ovarian epithelial cells from post-menopausal women to differentiate into cells with properties of oocytes (eggs), with potential implications for both fertility treatment and stem cell research. | 0 | Theoretical and Fundamental Chemistry |
In the elementary form of the continuity equation for mass, in hydrodynamics:
In elementary classical mechanics, mass flow rate is encountered when dealing with objects of variable mass, such as a rocket ejecting spent fuel. Often, descriptions of such objects erroneously invoke Newtons second law by treating both the mass and the velocity as time-dependent and then applying the derivative product rule. A correct description of such an object requires the application of Newtons second law to the entire, constant-mass system consisting of both the object and its ejected mass.
Mass flow rate can be used to calculate the energy flow rate of a fluid:
where is the unit mass energy of a system.
Energy flow rate has SI units of kilojoule per second or kilowatt. | 1 | Applied and Interdisciplinary Chemistry |
2,4,6-Tri-tert-butylpyrimidine is the organic compound with the formula HC(BuC)NCBu where Bu = (CH)C. It is a substituted derivative of the heterocycle pyrimidine. Known also as TTBP, this compound is of interest as a base that is sufficiently bulky to not bind boron trifluoride but still able to bind protons. It is less expensive that the related bulky derivatives of pyridine such as 2,6-di-tert-butylpyridine, 2,4,6-tri-tert-butylpyridine, and 2,6-di-tert-butyl-4-methylpyridine. | 0 | Theoretical and Fundamental Chemistry |
The Lafitte Greenway in New Orleans, Louisiana, is a post-Hurricane Katrina revitalization effort that utilizes green infrastructure to improve water quality as well as support wildlife habitat. The site was previously an industrial corridor that connected the French Quarter to Bayou St. John and Lake Pontchartrain. Part of the revitalization plan was to incorporate green infrastructure for environmental sustainability. One strategy to mitigate localized flooding was to create recreation fields that are carved out to hold water during times of heavy rains. Another strategy was to restore the native ecology of the corridor, giving special attention to the ecotones that bisect the site. The design proposed retrofitting historic buildings with stormwater management techniques, such as rainwater collection systems, which allows historic buildings to be preserved. This project received the Award of Excellence from the ASLA in 2013. | 1 | Applied and Interdisciplinary Chemistry |
Meanwhile, geneticists and molecular biologists have characterised five genes that appear to encode muscarinic receptors, named m1-m5 (lowercase m; no subscript number). They code for pharmacologic types M-M. The receptors m1 and m2 were determined based upon partial sequencing of M and M receptor proteins. The others were found by searching for homology, using bioinformatic techniques. | 1 | Applied and Interdisciplinary Chemistry |
As with many other places in Britain, there have been speculative articles written that connect Ariconium to the characters in Arthurian tales. Some are careful with their wording and state that they are not asserting historical facts; others are less careful and propagate fiction in the guise of hypothesis.
There are occasional mentions of Ariconium in poetic works, but there is nothing to connect them with the Ariconium of this article. They may be references to Kenchester at a time when Camden placed the site there, or to a similar-sounding word such as Uriconium, or to some other place or person; or as works of poetry, they may refer to nothing in particular at all. | 1 | Applied and Interdisciplinary Chemistry |
Erämetsä attended Kuopio Lyseo as an undergraduate in 1925. He continued to study chemistry at the Helsinki University of Technology, where he graduated with a M.Sc. in engineering in 1934 and a Ph.D. in technology in 1938. His Ph.D. work dealt with detection of the presence of indium in Finnish minerals. | 1 | Applied and Interdisciplinary Chemistry |
A consumption map or efficiency map shows the brake-specific fuel consumption in g per kWh over mean effective pressure per rotational speed of an internal combustion engine.
The x-axis shows the rotational speed range. The y-axis represents the load on the engine. The contour lines show the specific fuel consumption, indicating the areas of the speed/load regime where the engine is more or less efficient.
The map contains each possible condition, combining rotational speed and mean effective pressure. It shows the result of specific fuel consumption. A typical rotation power output P (linear to ) is reached on several locations on the map but differing in the amount of fuel consumption. Automatic transmissions, are designed to keep the engine at the speed with the lowest possible fuel consumption, given the power demand.
The map also shows the efficiency of the engine. Depending on the fuel type, diesel and gasoline engines reach up to 210 g/kWh and about 40% efficiency. Using natural gas this efficiency is reached at 200 g/kWh.
Average values are 160–180 g/kWh for slow moving two stroke diesel cargoship engines using fuel oil, reaching up to 55% efficiency at 300 rpm. 195–210 g/kWh at cooled and pre-charged diesel engines for passenger cars, trucks 195–225 g/kWh. Non-charged Otto cycle gasoline engines for passenger cars 250–350 g/kWh. | 0 | Theoretical and Fundamental Chemistry |
There are two main variants of thermochromic ink, one composed of leuco dyes and one composed of liquid crystals. For both types of ink, the chemicals need to be contained within capsules around 3 to 5 microns long. This protects the dyes and crystals from mixing with other chemicals that might affect the functionality of the ink. | 0 | Theoretical and Fundamental Chemistry |
Carbon dioxide forms carbonic acid when dissolved in water, so ocean acidification is a significant consequence of elevated carbon dioxide levels, and limits the rate at which it can be absorbed into the ocean (the solubility pump). A variety of different bases have been suggested that could neutralize the acid and thus increase absorption. For example, adding crushed limestone to oceans enhances the absorption of carbon dioxide. Another approach is to add sodium hydroxide to oceans which is produced by electrolysis of salt water or brine, while eliminating the waste hydrochloric acid by reaction with a volcanic silicate rock such as enstatite, effectively increasing the rate of natural weathering of these rocks to restore ocean pH. | 0 | Theoretical and Fundamental Chemistry |
Toc159 is another GTP binding TOC subunit, like Toc34. Toc159 has three domains. At the N-terminal end is the A-domain, which is rich in acidic amino acids and takes up about half the protein length. The A-domain is often cleaved off, leaving an 86 kilodalton fragment called Toc86. In the middle is its GTP binding domain, which is very similar to the homologous GTP-binding domain in Toc34. At the C-terminal end is the hydrophilic M-domain, which anchors the protein to the outer chloroplast membrane.
Toc159 probably works a lot like Toc34, recognizing proteins in the cytosol using GTP. It can be regulated through phosphorylation, but by a different protein kinase than the one that phosphorylates Toc34. Its M-domain forms part of the tunnel that chloroplast preproteins travel through, and seems to provide the force that pushes preproteins through, using the energy from GTP.
Toc159 is not always found as part of the TOC complex—it has also been found dissolved in the cytosol. This suggests that it might act as a shuttle that finds chloroplast preproteins in the cytosol and carries them back to the TOC complex. There isn't a lot of direct evidence for this behavior though.
A family of Toc159 proteins, Toc159, Toc132, Toc120, and Toc90 have been found in Arabidopsis thaliana. They vary in the length of their A-domains, which is completely gone in Toc90. Toc132, Toc120, and Toc90 seem to have specialized functions in importing stuff like nonphotosynthetic preproteins, and can't replace Toc159. | 0 | Theoretical and Fundamental Chemistry |
Minipreparation of plasmid DNA is a rapid, small-scale isolation of plasmid DNA from bacteria. Commonly used miniprep methods include alkaline lysis and spin-column based kits. It is based on the alkaline lysis method. The extracted plasmid DNA resulting from performing a miniprep is itself often called a "miniprep".
Minipreps are used in the process of molecular cloning to analyze bacterial clones. A typical plasmid DNA yield of a miniprep is 5 to 50 µg depending on the cell strain.
Miniprep of a large number of plasmids can also be done conveniently on filter paper by lysing the cell and eluting the plasmid on to filter paper. | 1 | Applied and Interdisciplinary Chemistry |
Vancomycin is considered a last resort medication for the treatment of sepsis and lower respiratory tract, skin, and bone infections caused by Gram-positive bacteria. The minimum inhibitory concentration susceptibility data for a few medically significant bacteria are:
* S. aureus: 0.25 μg/mL to 4.0 μg/mL
* S. aureus (methicillin resistant or MRSA): 1 μg/mL to 138 μg/mL
* S. epidermidis: ≤0.12 μg/mL to 6.25 μg/mL | 0 | Theoretical and Fundamental Chemistry |
Founded as the American Institute of Mining Engineers (AIME), the institute had a membership at the beginning of 1915 of over 5,000, made up of honorary, elected, and associate members. The annual meeting of the institute was held in February, with other meetings during the year as authorized by the council. The institute published three volumes of Transactions annually and a monthly Bulletin which appeared on the first of each month. The headquarters of the institute was in the Engineering Building in New York City.
Following creation of the Petroleum Division in 1922, the Iron and Steel Division in 1928 and the Institute of Metals Division in 1933 the name of the society was changed in 1957 to the American Institute of Mining, Metallurgical and Petroleum Engineers. Three of the current member societies were then created from the divisions, increasing to four in 1974 when the Iron and Steel Society (ISS) was formed. In 2004 ISS merged with the Association of Iron and Steel Engineers (AISE) to form the Association for Iron and Steel Technology (AIST) whilst remaining a member society of AIME. | 1 | Applied and Interdisciplinary Chemistry |
Insertion element (also known as an IS, an insertion sequence element, or an IS element) is a short DNA sequence that acts as a simple transposable element. Insertion sequences have two major characteristics: they are small relative to other transposable elements (generally around 700 to 2500 bp in length) and only code for proteins implicated in the transposition activity (they are thus different from other transposons, which also carry accessory genes such as antibiotic resistance genes). These proteins are usually the transposase which catalyses the enzymatic reaction allowing the IS to move, and also one regulatory protein which either stimulates or inhibits the transposition activity. The coding region in an insertion sequence is usually flanked by inverted repeats. For example, the well-known IS911 (1250 bp) is flanked by two 36bp inverted repeat extremities and the coding region has two genes partially overlapping orfA and orfAB, coding the transposase (OrfAB) and a regulatory protein (OrfA). A particular insertion sequence may be named according to the form ISn, where n is a number (e.g. IS1, IS2, IS3, IS10, IS50, IS911, IS26 etc.); this is not the only naming scheme used, however. Although insertion sequences are usually discussed in the context of prokaryotic genomes, certain eukaryotic DNA sequences belonging to the family of Tc1/mariner transposable elements may be considered to be, insertion sequences.
In addition to occurring autonomously, insertion sequences may also occur as parts of composite transposons; in a composite transposon, two insertion sequences flank one or more accessory genes, such as an antibiotic resistance gene (e.g. Tn10, Tn5). Nevertheless, there exist another sort of transposons, called unit transposons, that do not carry insertion sequences at their extremities (e.g. Tn7).
A complex transposon does not rely on flanking insertion sequences for resolvase. The resolvase is part of the tns genome and cuts at flanking inverted repeats.
Transposition frequency of IS elements is dependent of multiple parameters, including culture growth phase, medium composition, oxygen tension, growth scale, and structural conformation of target sites (e.g.: curvature, presence of certain motifs, DNA composition).. Recombination between genomic IS sites can enable bacteria to adapt to new environments, making IS elements an important mechanism for evolution in bacteria. | 1 | Applied and Interdisciplinary Chemistry |
Rectal administration is an off-label use of vancomycin for the treatment of Clostridium difficile infection. | 0 | Theoretical and Fundamental Chemistry |
The syndetome location within the somite is determined by FGF secreted from the center of the myotome (a collection of embryonic tissue that develops into skeletal muscle)- the FGF then induces the adjacent anterior and posterior sclerotome (a collection of embryonic tissue that develops into the axial skeleton) to adopt a tendon cell fate. This ultimately places future scleraxis-expressing cells between the two tissue types they will ultimately join.
Scleraxis expression will be seen throughout the entire sclerotome (rather than just the sclerotome directly anterior and posterior to the myotome) with an overexpression of FGF8, demonstrating that all sclerotome cells are capable of expressing scleraxis in response to FGF signaling. While the FGF interaction has been shown to be necessary for scleraxis expression, it is still unclear as to whether the FGF signaling pathway directly induces the syndetome to secrete scleraxis, or indirectly through a secondary signaling pathway. Most likely, the syndetomal cells, through careful reading of the FGF concentration (coming from the myotome), can precisely determine their location and begin expressing scleraxis. Much of embryonic development follows this model of inducing specific cell fates through the reading of surrounding signaling molecule concentration gradients. | 1 | Applied and Interdisciplinary Chemistry |
Fluids that have a linear shear stress/shear strain relationship but require a finite yield stress before they begin to flow (the plot of shear stress against shear strain does not pass through the origin) are called Bingham plastics. Several examples are clay suspensions, drilling mud, toothpaste, mayonnaise, chocolate, and mustard. The surface of a Bingham plastic can hold peaks when it is still. By contrast Newtonian fluids have flat featureless surfaces when still. | 1 | Applied and Interdisciplinary Chemistry |
Exposure to PFAS is a risk factor for various hypertensive disorders in pregnancy, including preeclampsia and high blood pressure. It is not clear whether PFAS exposure is associated with wider cardiovascular disorders during pregnancy. Human breast milk has the capability to harbor PFAs as well as be transferred from mother to infant through breastfeeding. | 0 | Theoretical and Fundamental Chemistry |
One type of system that combines secondary treatment and settlement is the cyclic activated sludge (CASSBR), or sequencing batch reactor (SBR). Typically, activated sludge is mixed with raw incoming sewage, and then mixed and aerated. The settled sludge is run off and re-aerated before a proportion is returned to the headworks.
The disadvantage of the CASSBR process is that it requires a precise control of timing, mixing and aeration. This precision is typically achieved with computer controls linked to sensors. Such a complex, fragile system is unsuited to places where controls may be unreliable, poorly maintained, or where the power supply may be intermittent. | 1 | Applied and Interdisciplinary Chemistry |
In differential calculus, the Reynolds transport theorem (also known as the Leibniz–Reynolds transport theorem), or simply the Reynolds theorem, named after Osborne Reynolds (1842–1912), is a three-dimensional generalization of the Leibniz integral rule. It is used to recast time derivatives of integrated quantities and is useful in formulating the basic equations of continuum mechanics.
Consider integrating over the time-dependent region that has boundary , then taking the derivative with respect to time:
If we wish to move the derivative into the integral, there are two issues: the time dependence of , and the introduction of and removal of space from due to its dynamic boundary. Reynolds transport theorem provides the necessary framework. | 1 | Applied and Interdisciplinary Chemistry |
Sulfenamides, e.g. cyclohexylthiophthalimide, are used extensively in the vulcanization of rubber. The sulfenamides are used to accelerate the process via the transient formation of labile S-N bonds. The substituents on the sulfenamides determine the point at which they will become active. Temperature dependent activation of sulfenamide accelerants is useful in the vulcanization process because the temperature at which the rubber polymerizes determines the length of the sulfur chains, and properties such as the elasticity of the final product. | 0 | Theoretical and Fundamental Chemistry |
A translation of the Oxford team's 1941 report reached Germany via Sweden the following year. Like most research in wartime Germany, research into penicillin was carried out in a fragmentary fashion with little coordination. On 6 December 1943, the Reich Health Ministry ordered the medical community to conduct research into penicillin and other antibiotics. Three vials of penicillin captured by the Afrika Korps reached Germany in 1943 and one was sent to Heinz Öppinger at Hoechst in Frankfurt, and he began conducting experiments with moulds. Penicillin was produced there in 300-litre batches, and Öppinger developed a rotating drum for a deep-tank fermentation process.
Research was also carried out by Schering in Berlin using a sample of Flemings mould, which they failed to cultivate; their efforts to determine the chemical structure of penicillin were also unsuccessful. Maria Brommelhues at IG Farbens Bacteriological Laboratory in Elberfeld catalogued different species of penicillin. Hitlers personal physician, Theodor Morell, treated Hitler with penicillin for injuries sustained in the 20 July 1944 assassination attempt. Information about penicillin research in Germany was gathered by the Manhattan Projects Alsos Mission and forwarded to Florey in the UK.
Much of Germany's penicillin came from Czechoslovakia, where research was carried out at Charles University in Prague and the Fragner Pharmaceutical Company by a team that included chemist Karel Wiesner. Work was also conducted in secret in France and at the Delft University of Technology in the Netherlands. In 1946 and 1947, penicillin factories were established in Belarus, Ukraine, Poland, Italy and Yugoslavia with plant and expertise from Canada through the United Nations Relief and Rehabilitation Administration (UNRRA), of which Canadian Lester B. Pearson was the head of its supply committee. UNRRA was wound up in 1948, and its penicillin responsibilities were transferred to the World Health Organization (WHO).
In Italy, Domenico Marotta negotiated with UNRRA for a penicillin plant to be built in Rome near the Sapienza University of Rome. This took longer than expected and construction did not commence until 1948. In the meantime, Chain came to the Istituto Superiore di Sanità to deliver a series of lectures on penicillin and Marotta took the opportunity to recruit him as a colleague. Chain suggested that instead of building a pilot plant, they use the UNRRA money to build an institute for research into penicillin. This became the largest of its kind in the world, with over one hundred chemists, biochemists, microbiologists and technicians, and was soon at the forefront of research into semisynthetic penicillin. | 1 | Applied and Interdisciplinary Chemistry |
An air-supported (or air-inflated) structure is any permanent building that derives its structural integrity from the use of internal pressurized air to inflate a pliable material (i.e. structural fabric) envelope, so that air is the main support of the structure. It is usually dome-shaped, since this shape creates the greatest volume for the least amount of material. However, rectangular inflatables are also possible, such as the Airtecture Exhibition Hall constructed by Festo AG & Co.
The concept was popularized on a large scale by David H. Geiger with the United States pavilion at Expo '70 in Osaka, Japan in 1970.
To maintain structural integrity, the structure must be pressurized such that the internal pressure equals or exceeds any external pressure being applied to the structure (i.e. wind pressure). The structure does not have to be airtight to retain structural integrity—as long as the pressurization system that supplies internal pressure replaces any air leakage, the structure will remain stable. All access to the structure interior must be equipped with two sets of doors or revolving door (airlock). Air-supported structures are secured by heavy weights on the ground, ground anchors, attached to a foundation, or a combination of these. | 1 | Applied and Interdisciplinary Chemistry |
The previously described work of Martin and Synge impacted the development of the previously known column chromatography and inspired new forms of chromatography such as countercurrent distribution, paper chromatography, and gas-liquid chromatography which is more commonly known as gas chromatography. The modification of silica gel stationary phase led to many creative ways of modifying stationary phases in order to influence the separation characteristics. The most notable modification was the chemical bonding of alkane functional groups to silica gel to produce reversed-phase media. The original problem that Martin and Synge encountered with devising an instrument that would employ two free-flowing liquid phases was solved by Lyman C. Craig in 1944, and commercial counter-current distribution instruments were used for many important discoveries. The introduction of paper chromatography was an important analytical technique which gave rise to thin-layer chromatography. Finally, gas-liquid chromatography, a fundamental technique in modern analytical chemistry, was described by Martin with coauthors A. T. James and G. Howard Smith in 1952. | 0 | Theoretical and Fundamental Chemistry |
The trifluoromethyl group has a significant electronegativity that is often described as being intermediate between the electronegativities of fluorine and chlorine. For this reason, trifluoromethyl-substituted compounds are often strong acids, such as trifluoromethanesulfonic acid and trifluoroacetic acid. Conversely, the trifluoromethyl group lowers the basicity of compounds like trifluoroethanol. | 0 | Theoretical and Fundamental Chemistry |
* Acetonyl group
* Acyl group (e.g. acetyl group, benzoyl group)
* Alkyl group (e.g., methyl group, ethyl group)
* Alkenyl group (e.g., vinyl group, allyl group)
* Alkynyl group (propargyl group)
* Benzyloxycarbonyl group (Cbz)
* tert-butoxycarbonyl group (Boc)
* Carboxyl group | 0 | Theoretical and Fundamental Chemistry |
Energy flows directionally through ecosystems, entering as sunlight (or inorganic molecules for chemoautotrophs) and leaving as heat during the many transfers between trophic levels. However, the matter that makes up living organisms is conserved and recycled. The six most common elements associated with organic molecules—carbon, nitrogen, hydrogen, oxygen, phosphorus, and sulfur—take a variety of chemical forms and may exist for long periods in the atmosphere, on land, in water, or beneath the Earth's surface. Geologic processes, such as weathering, erosion, water drainage, and the subduction of the continental plates, all play a role in this recycling of materials. Because geology and chemistry have major roles in the study of this process, the recycling of inorganic matter between living organisms and their environment is called a biogeochemical cycle.
The six aforementioned elements are used by organisms in a variety of ways. Hydrogen and oxygen are found in water and organic molecules, both of which are essential to life. Carbon is found in all organic molecules, whereas nitrogen is an important component of nucleic acids and proteins. Phosphorus is used to make nucleic acids and the phospholipids that comprise biological membranes. Sulfur is critical to the three-dimensional shape of proteins. The cycling of these elements is interconnected. For example, the movement of water is critical for leaching sulfur and phosphorus into rivers which can then flow into oceans. Minerals cycle through the biosphere between the biotic and abiotic components and from one organism to another. | 0 | Theoretical and Fundamental Chemistry |
The Qing dynasty Yongzheng Emperor (r. 1722–1735) was the last Chinese ruler known to die from elixir poisoning. He was a superstitious man, affected by portents and omens, and a firm believer in Daoist longevity techniques. Taking immortality elixirs is thought to have caused his sudden death in 1735. | 1 | Applied and Interdisciplinary Chemistry |
Photoresists are light-sensitive materials, composed of a polymer, a sensitizer, and a solvent. Each element has a particular function. The polymer changes its structure when it is exposed to radiation. The solvent allows the photoresist to be spun and to form thin layers over the wafer surface. Finally, the sensitizer, or inhibitor, controls the photochemical reaction in the polymer phase.
Photoresists can be classified as positive or negative. In positive photoresists, the photochemical reaction that occurs during exposure, weakens the polymer, making it more soluble to the developer so the positive pattern is achieved. Therefore, the masks contains an exact copy of the pattern, which is to remain on the wafer, as a stencil for subsequent processing. In the case of negative photoresists, exposure to light causes the polymerization of the photoresist so the negative resist remains on the surface of the substrate where it is exposed, and the developer solution removes only the unexposed areas. Masks used for negative photoresists contain the inverse or photographic “negative” of the pattern to be transferred. Both negative and positive photoresists have their own advantages. The advantages of negative photoresists are good adhesion to silicon, lower cost, and a shorter processing time. The advantages of positive photoresists are better resolution and thermal stability. | 0 | Theoretical and Fundamental Chemistry |
Toxicants that at low concentrations modify or inhibit some biological process by binding at a specific site or molecule have a specific acting mode of toxic action. However, at high enough concentrations, toxicants with specific acting modes of toxic actions can produce narcosis that may or may not be reversible. Nevertheless, the specific action of the toxicant is always shown first because it requires lower concentrations.
There are several specific acting modes of toxic action:
* Uncouplers of oxidative phosphorylation. Involves toxicants that uncouple the two processes that occur in oxidative phosphorylation: electron transfer and adenosine triphosphate (ATP) production.
* Acetylcholinesterase (AChE) inhibitors. AChE is an enzyme associated with nerve synapses that it’s designed to regulate nerve impulses by breaking down the neurotransmitter Acetylcholine (ACh). When toxicants bind to AChE, they inhibit the breakdown of ACh. This results in continued nerve impulses across the synapses, which eventually cause nerve system damage. Examples of AChE inhibitors are organophosphates and carbamates, which are components found in pesticides (see Acetylcholinesterase inhibitors).
* Irritants. These are chemicals that cause an inflammatory effect on living tissue by chemical action at the site of contact. The resulting effect of irritants is an increase in the volume of cells due to a change in size (hypertrophy) or an increase in the number of cells (hyperplasia). Examples of irritants are benzaldehyde, acrolein, zinc sulphate and chlorine.
* Central nervous system (CNS) seizure agents. CNS seizure agents inhibit cellular signaling by acting as receptor antagonists. They result in the inhibition of biological responses. Examples of CNS seizure agents are organochlorine pesticides.
* Respiratory blockers. These are toxicants that affect respiration by interfering with the electron transport chain in the mitochondria. Examples of respiratory blockers are rotenone and cyanide. | 1 | Applied and Interdisciplinary Chemistry |
Armando Reguscis version of the air engine couples the transmission system directly to the wheel, and has variable torque from zero to the maximum, enhancing efficiency. Reguscis patents date from 1990. | 1 | Applied and Interdisciplinary Chemistry |
Piperacillin is used almost exclusively in combination with the beta lactamase inhibitor tazobactam for the treatment of serious, hospital-acquired infections. This combination is among the most widely used drug therapies in United States non-federal hospitals, accounting for $388M in spending in spite of being a low-cost generic drug.
Piperacillin-tazobactam is recommended as part of a three-drug regimen for the treatment of hospital-acquired pneumonia suspected as being due to infection by multi-drug resistant pathogens. It is also one of several antibacterial drugs recommended for the treatment of infections known to be caused by anaerobic Gram-negative rods.
Piperacillin-tazobactam is recommended by the National Institute for Health and Care Excellence as initial empiric treatment for people with suspected neutropenic sepsis.
Piperacillin is used to treat patients diagnosed with various internal infections such as abdominal, bacteremia, gynecological, respiratory, and urinary, mainly caused by Pseudomonas aeruginosa and other infectious bacteria. They are primarily used in current and former neutropenic patients, and patients with biliary tract infections. Other uses include applications in surgical infection prophylaxis; in biliary surgery, a single dose of piperacillin is administered intravenously to inhibit the development of acute cholangitis and prevent wound infections. The combination of piperacillin and an aminoglycoside is commonly used to treat severe infections, but due to the incompatibilities in drug interaction, they are administered separately. | 0 | Theoretical and Fundamental Chemistry |
The use of modafinil as a supposed cognitive enhancer may be considered as cheating, unnatural, or risky. The University of Sussex explained that it is a prescription drug and the decision should be made by the doctor on whether to prescribe modafinil to a student. As a matter of bioethics, the US President's Council on Bioethics argued that excellence achieved through the use of drugs like modafinil is "cheap" as it obviates the need for hard work and study, and is not fully authentic because the excellence is partly attributable to the drug, not the individual. Alternately, people in environments like Wall Street trading may not view the use of modafinil as cheating, believing that if modafinil can give them an edge and they are aware of the risks involved, it should not be considered as cheating. Due to such varying views, modafinil users for narcolepsy may cope with stigma by hiding, denying, or justifying their use, or by seeking support from others who share their views or experiences. | 0 | Theoretical and Fundamental Chemistry |
In the late nineteenth century, chemists, including William Crookes, President of the British Association for the Advancement of Science in 1898, predicted that the demand for nitrogen compounds, either in the form of fertilizer or explosives, would exceed supply in the near future.
Following the work by Claude Louis Berthollet published in 1784, chemists knew ammonia to be a nitrogen compound. Early attempts to synthesize ammonia were performed in 1795 by Georg Friedrich Hildebrandt. Several others were made during the nineteenth century.
In the 1870s, ammonia was an unwanted byproduct of making manufactured gas. Its importance emerged later, and in the 1900s the industry modified their facilities to produce it from coke. Still, production could not meet demand.
In 1900, Chile, with its deposits of saltpeter, produced two-thirds of all fertilizer on the planet. However, these deposits rapidly diminished, the industry was dominated by an oligopoly and the cost of saltpeter rose constantly. To ensure food security for Europe's growing population, it was essential that a new economical and reliable method of obtaining ammonia be developed.
Issues of food security were particularly acute in Germany. Its soil was poor and the country lacked an empire. A major consumer of Chilean saltpeter, Germany saltpeter imports totaled 350,000 tonnes in 1900. Twelve years later, it imported 900,000 tonnes. The United States was in much better position due to the Guano Islands Act.
In the years between 1890 and 1900, chemistry advanced on several fronts, and more scientists attempted to fix atmospheric nitrogen. In 1895, German chemists Adolf Frank and Nikodem Caro succeeded in reacting calcium carbide with dinitrogen to obtain calcium cyanamide, a chemical compound used as a fertilizer. Industrialization of the Frank-Caro process began in 1905. By 1918, there were 35 synthesis sites fixing 325,000 tonnes of nitrogen annually. However, the Cyanamide process consumed large amounts of electrical power and was more labor-intensive than the Haber process. Today, cyanamide is used primarily as a herbicide.
Wilhelm Ostwald, considered one of the best German chemists of the early twentieth century, attempted to synthesize ammonia in 1900 using an invention. He interested BASF, who asked Carl Bosch, a recently hired chemist, to validate the device.
In 1901, Henry Le Chatelier managed to synthesize ammonia from air. After obtaining a patent, he claimed it was possible to obtain better performance by increasing the pressure. When one of his assistants was killed following the accidental explosion of a device, Le Chatelier decided to end his research.
In 1905, Norwegian physicist Kristian Birkeland, funded by engineer and industrialist Samuel Eyde, developed the Birkeland–Eyde process which fixes atmospheric nitrogen as nitrogen oxides. The Birkeland–Eyde process requires a considerable amount of electricity, constraining possible site location; fortunately, Norway possessed several sites capable of meeting these needs. Norsk Hydro was founded 2 December 1905 to commercialize the new process. In 1911, the Norsk Hydro facility was consuming 50,000 kW, the next year, consumption doubled to 100,000 kW. By 1913, Norsk Hydro's facilities were producing 12,000 tonnes of nitrogen, about 5 percent of the volume extracted from coke at the time.
Similar processes were developed at the time. Schönherr, an employee of BASF, worked on a nitrogen fixation process beginning in 1905. In 1919, Schönherr's Badische process was employed at Norsk Hydro facilities. That same year, the Pauling process was used in Germany and the United States.
All these methods were quickly supplanted by the less-expensive Haber process. | 1 | Applied and Interdisciplinary Chemistry |
The term "doublet" dates back to the 19th century, when it was observed that certain spectral lines of an ionized, excited gas would split into two under the influence of a strong magnetic field, in an effect known as the anomalous Zeeman effect. Such spectral lines were observed not only in the laboratory, but also in astronomical spectroscopy observations, allowing astronomers to deduce the existence of, and measure the strength of magnetic fields around the Sun, stars and galaxies. Conversely, it was the observation of doublets in spectroscopy that allowed physicists to deduce that the electron had a spin, and that furthermore, the magnitude of the spin had to be 1/2. See the history section of the article on Spin (physics) for greater detail.
Doublets continue to play an important role in physics. For example, the healthcare technology of magnetic resonance imaging is based on nuclear magnetic resonance. In this technology, a spectroscopic doublet occurs in a spin-1/2 atomic nucleus, whose doublet splitting is in the radio-frequency range. By applying both a magnetic field and carefully tuning a radio-frequency transmitter, the nuclear spins will flip and re-emit radiation, in an effect known as the Rabi cycle. The strength and frequency of the emitted radio waves allows the concentration of such nuclei to be measured. Another potential application is the use of doublets as the emitting layer in light emitting diodes (LEDs). These materials have the advantage of having 100% theoretical quantum efficiency based on spin statistics whereas singlet systems and triplet systems have significantly lower efficiencies or rely on noble metals such as Pt and Ir to emit light. | 0 | Theoretical and Fundamental Chemistry |
An overflow is required for excess steam or water to discharge, especially during starting. If the injector cannot initially overcome boiler pressure, the overflow allows the injector to continue to draw water and steam. | 1 | Applied and Interdisciplinary Chemistry |
Carbyne molecules are generally found to be in electronic doublet states: the non-bonding electrons on carbon are arranged as one radical (unpaired electron) and one electron pair, leaving a vacant atomic orbital, rather than being a triradical (the quartet state). The simplest case is the CH radical, which has an electron configuration . Here the 1σ molecular orbital is essentially the carbon 1s atomic orbital, and the 2σ is the C–H bonding orbital formed by overlap of a carbon sp hybrid orbital with the hydrogen 1s orbital. The 3σ is a carbon non-bonding orbital pointing along the C–H axis away from the hydrogen, while there are two non-bonding 1π orbitals perpendicular to the C–H axis. However the 3σ is an sp hybrid which has lower energy than the 1π orbital which is pure p, so the 3σ is filled before the 1π. The CH radical is in fact isoelectronic with the nitrogen atom which does have three unpaired electrons in accordance with Hund's rule of maximum multiplicity. However the nitrogen atom has three degenerate p orbitals, in contrast to the CH radical where hybridization of one orbital (the 3σ) leads to an energy difference. | 0 | Theoretical and Fundamental Chemistry |
This protein is a member of a RNA-binding protein family that regulates transcription and RNA translation. It was first identified in cytotoxic lymphocyte (CTL) target cells. TIA1 acts in the nucleus to regulate splicing and transcription. TIA1 helps to recruit the splicesome to regulate RNA splicing, and it inhibits transcription of multiple genes, such as the cytokine Tumor necrosis factor alpha. In response to stress, TIA1 translocates from the nucleus to the cytoplasm, where it nucleates a type of RNA granule, termed the stress granule, and participates in the translational stress response. As part of the translational stress response, TIA1 works in cooperation with other RNA binding proteins to sequester RNA transcripts away from the ribosome, which allows the cell to focus its protein synthesis/RNA translation machinery on producing proteins that will address the particular stress. It has been suggested that this protein may be involved in the induction of apoptosis as it preferentially recognizes poly(A) homopolymers and induces DNA fragmentation in CTL targets. The major granule-associated species is a 15-kDa protein that is thought to be derived from the carboxyl terminus of the 40-kDa product by proteolytic processing. Alternative splicing resulting in different isoforms of this gene product have been described. | 1 | Applied and Interdisciplinary Chemistry |
Fluorescence-emission Polymer is a kind of polymer which can absorb light of certain frequency and then give out light. These polymers can be applied in biomaterial area. Due to their high biocapacity and fluorescence, they can help researchers to find and mark the location of proteins. And polymers with property of aggregation-induced emission can also help to protect the healthy tissues from the harm of the medicines. | 0 | Theoretical and Fundamental Chemistry |
Asemota has a long history of international consultancy in matters of food security and biotechnology. She was an international technical expert for the European Union (1994-1995), and served the United Nations Technical Cooperation among Developing Countries (TCDC) Programmes as International Technical Cooperation Programmes (TCP). She served as an International Biotechnology consultant to the United Nations Food and Agriculture Organisation from 2001. This included consulting for the International Technical Cooperation for Syria with the Developing Countries Programmes in 2001 and as technical lead on food sufficiency for the National Seed Potato Production Programme in the Republic of Tajikistan between 2003 and 2007. She periodically serves the UN-FAO Seed Production Programmes as an International Consultant. | 1 | Applied and Interdisciplinary Chemistry |
* For cables we provide wall/deck penetration sleeve to avoid any damage to cable from material shifting on deck.
* Deck penetrations on offshore platform provided to avoid water/chemical dripping to lower deck in case of spillage.
* Acts as toe guard.
* For wall penetrations it can be a type of strengthening.
* Together with packing it helps to protect from fire spread from one room to other. | 1 | Applied and Interdisciplinary Chemistry |
In neurons of the human brain, somatic recombination occurs frequently in the gene that encodes APP. Neurons from individuals with sporadic Alzheimers disease show greater APP' gene diversity due to somatic recombination than neurons from healthy individuals. | 1 | Applied and Interdisciplinary Chemistry |
Biomarkers of susceptibility are indicators of the natural characteristics of an organism that make it more susceptible to the effects of an exposure to a chemical. They can help define what sensitivities are more susceptible as well as critical times when exposures can be most detrimental. For example, the exhalation strength of an asthmatic will indicate how susceptible that person would be to the respiratory effects of exposure to brevetoxin, the toxic compound produced during a red tide. | 1 | Applied and Interdisciplinary Chemistry |
In electric discharges, for example as laboratory discharges between two electrodes or as lightning discharges between cloud and ground or within clouds, electrons produce Bremsstrahlung photons while scattering off air molecules. These photons become manifest in terrestrial gamma-ray flashes and are the source for beams of electrons, positrons, neutrons and protons. The appearance of Bremsstrahlung photons also influences the propagation and morphology of discharges in nitrogen-oxygen mixtures with low percentages of oxygen. | 0 | Theoretical and Fundamental Chemistry |
A disadvantage of using nanocrystals for drug delivery is nanocrystal stability. Instability problems of nanocrystalline structures derive from thermodynamic processes such as particle aggregation, amorphization, and bulk crystallization. Particles at the nanoscopic scale feature a relative excess of Gibbs free energy, due to their higher surface area to volume ratio. To reduce this excess energy, it is generally favorable for aggregation to occur. Thus, individual nanocrystals are relatively unstable by themselves and will generally aggregate. This is particularly problematic in top-down production of nanocrystals. Methods such as high-pressure homogenization and bead milling, tend to increase instabilities by increasing surface areas; to compensate, or as a response to high pressure, individual particles may aggregate or turn amorphous in structure. Such methods can also lead to the reprecipitation of the drug by surpassing the solubility beyond the saturation point (Ostwald ripening).
One method to overcome aggregation and retain or increase nanocrystal stability is by use of stabilizer molecules. These molecules, which interact with the surface of the nanocrystals and prevent aggregation via ionic repulsion or steric barriers between the individual nanocrystals, include surfactants and are generally useful for stabilizing suspensions of nanocrystals. Concentrations of surfactants that are too high, however, may inhibit nanocrystal stability and enhance crystal growth or aggregation. It has been shown that certain surfactants, upon reaching a critical concentration, begin to self-assemble into micelles, which then compete with nanocrystal surfaces for other surfactant molecules. With fewer surface molecules interacting with the nanocrystal surface, crystal growth and aggregation is reported to occur at increased amounts. Use of surfactant at optimal concentrations reportedly allows for higher stability, larger drug capacity as a carrier, and sustained drug release. In a study using PEG as a stabilizer was found that nanocrystals treated with PEG enhanced accumulation at tumor sites and had greater blood circulation, than those not treated with PEG.
Amorphization can occur in top-down methods of production. With different intramolecular arrangements, amorphization of nanocrystals leads to different thermodynamic and kinetic properties that affect drug delivery and kinetics. Transition to amorphous structures is reported to occur through production practices such as spray drying, lyophilization, and mechanical mechanisms, such as milling. This amorphization has been reportedly observed with or without the presence of stabilizer in a dry milling process. Using a wet milling process with surfactant, however significantly reduced amorphization, suggesting that solvent, in this case water, and surfactant could inhibit amorphization for some top-down production methods that otherwise reportedly facilitate amorphization. | 0 | Theoretical and Fundamental Chemistry |
Some metals, particularly nickel and nickel alloys, can be made into nanocrystalline foils using electrodeposition. | 1 | Applied and Interdisciplinary Chemistry |
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