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PDE5 inhibitors have broad-ranging effects on the cardiovascular system beyond their acute haemodynamic influence. For example, PDE5 inhibitors have been shown to improve several parameters of endothelial function. Increasingly, their use in the management of systemic hypertension (including treatment-resistant hypertension), cardioprotection, heart failure, and peripheral arterial disease are being evaluated. | 1 | Applied and Interdisciplinary Chemistry |
Galenic formulation deals with the principles of preparing and compounding medicines in order to optimize their absorption. Galenic formulation is named after Claudius Galen, a 2nd Century AD Greek physician, who codified the preparation of drugs using multiple ingredients. Today, galenic formulation is part of pharmaceutical formulation. The pharmaceutical formulation of a medicine affects the pharmacokinetics, pharmacodynamics and safety profile of a drug. | 1 | Applied and Interdisciplinary Chemistry |
Depending on how many targets or analytes are being measured:
#Usual assays are simple or single target assays which is usually the default unless it is called multiplex.
#Multiplex assays are used to simultaneously measure the presence, concentration, activity, or quality of multiple analytes in a single test. The advent of multiplexing enabled rapid, efficient sample testing in many fields, including immunology, cytochemistry, genetics/genomics, pharmacokinetics, and toxicology. | 1 | Applied and Interdisciplinary Chemistry |
Acquired immunodeficiency syndrome (AIDS) is a leading cause of death in the world. It was identified as a disease in 1981. Two years later the etiology agent for AIDS, the HIV was described. HIV is a retrovirus and has two major serotypes, HIV-1 and HIV-2. The pandemic mostly involves HIV-1 while HIV-2 has lower morbidity rate and is mainly restricted to western Africa.
In the year 2009 over 40 million people were infected worldwide with HIV and the number keeps on growing. The vast majority of infected individuals live in the developing countries.
HIV drugs do not cure HIV infection, but the treatment aims at improving the quality of patients´ lives and decreased mortality.
25 antiretroviral drugs were available in 2009 for the treatment of HIV infection. The drugs belong to six different classes that act at different targets. The most popular target in the field of antiretroviral drug development is the HIV-1 reverse transcriptase (RT) enzyme.
There are two classes of drugs that target the HIV-1 RT enzyme, nucleoside/nucleotide reverse-transcriptase inhibitors (NRTIs/NtRTIs) and non-nucleoside reverse-transcriptase inhibitors (NNRTIs). Drugs in these classes are important components of the HIV combination therapy called highly active antiretroviral therapy, better known as HAART.
In 1987, the first drug for the treatment of HIV infection was approved by the U.S. Food and Drug Administration (FDA). This was the NRTI called zidovudine. In the late 1980s, during further development of NRTIs, the field of NNRTIs discovery began. The development of NNRTIs improved quickly into the 1990s and they soon became the third class of antiretroviral drugs, following the protease inhibitors.
The NNRTIs are HIV-1 specific and have no activity against HIV-2 and other retroviruses. The first NNRTI, nevirapine was discovered by researchers at Boehringer Ingelheim and approved by the FDA in 1996. In the next two years two other NNRTIs were approved by the FDA, delavirdine in 1997 and efavirenz in 1998. These three drugs are so-called first generation NNRTIs. The need for NNRTIs with better resistance profile led to the development of the next generation of NNRTIs. Researchers at Janssens Foundation and Tibotec discovered the first drug in this class, etravirine, which was approved by the FDA in 2008. The second drug in this class, rilpivirine, was also discovered by Tibotec and was approved by the FDA in 2011. In addition to these four NNRTIs several other are in clinical development. | 1 | Applied and Interdisciplinary Chemistry |
This algorithm is performed on a Lewis structure (a diagram that shows all valence electrons). Oxidation state equals the charge of an atom after each of its heteronuclear bonds has been assigned to the more-electronegative partner of the bond (except when that partner is a reversibly bonded Lewis-acid ligand) and homonuclear bonds have been divided equally:
where each "—" represents an electron pair (either shared between two atoms or solely on one atom), and "OS" is the oxidation state as a numerical variable.
After the electrons have been assigned according to the vertical red lines on the formula, the total number of valence electrons that now "belong" to each atom is subtracted from the number of valence electrons of the neutral atom (such as 5 for nitrogen in group 15) to yield that atom's oxidation state.
This example shows the importance of describing the bonding. Its summary formula, , corresponds to two structural isomers; the peroxynitrous acid in the above figure and the more stable nitric acid. With the formula , the simple approach without bonding considerations yields −2 for all three oxygens and +5 for nitrogen, which is correct for nitric acid. For the peroxynitrous acid, however, the two oxygens in the O–O bond each has OS = −1 and the nitrogen has OS = +3, which requires a structure to understand.
Organic compounds are treated in a similar manner; exemplified here on functional groups occurring in between methane () and carbon dioxide ():
Analogously for transition-metal compounds; on the left has a total of 36 valence electrons (18 pairs to be distributed), and hexacarbonylchromium () on the right has 66 valence electrons (33 pairs):
A key step is drawing the Lewis structure of the molecule (neutral, cationic, anionic): atom symbols are arranged so that pairs of atoms can be joined by single two-electron bonds as in the molecule (a sort of "skeletal" structure), and the remaining valence electrons are distributed such that sp atoms obtain an octet (duet for hydrogen) with a priority that increases in proportion with electronegativity. In some cases, this leads to alternative formulae that differ in bond orders (the full set of which is called the resonance formulas). Consider the sulfate anion () with 32 valence electrons; 24 from oxygens, 6 from sulfur, 2 of the anion charge obtained from the implied cation). The bond orders to the terminal oxygens do not affect the oxidation state so long as the oxygens have octets. Already the skeletal structure, top left, yields the correct oxidation states, as does the Lewis structure, top right (one of the resonance formulas):
The bond-order formula at the bottom is closest to the reality of four equivalent oxygens each having a total bond order of 2. That total includes the bond of order to the implied cation and follows the rule requiring that the main-group atom's bond order equals valence electrons of the neutral atom, enforced with a priority that proportionately increases with electronegativity.
This algorithm works equally for molecular cations composed of several atoms. An example is the ammonium cation of 8 valence electrons (5 from nitrogen, 4 from hydrogens, minus 1 electron for the cation's positive charge):
Drawing Lewis structures with electron pairs as dashes emphasizes the essential equivalence of bond pairs and lone pairs when counting electrons and moving bonds onto atoms. Structures drawn with electron dot pairs are of course identical in every way: | 0 | Theoretical and Fundamental Chemistry |
In 1906 Ehrlich developed a new derivative of arsenic compound, which he code-named Compound 606 (the number representing the series of all his tested compounds). The compound was effective against malaria infection in experimental animals. In 1905, Fritz Schaudinn and Erich Hoffmann identified a spirochaete bacterium (Treponema pallidum) as the causative organism of syphilis. With this new knowledge, Ehrlich tested Compound 606 (chemically arsphenamine) on a syphilis-infected rabbit. He did not recognise its effectiveness. Sahachiro Hata went over Ehrlich's work and found on 31 August 1909 that the rabbit, which had been injected with Salvarsan 606, was cured using only a single dose, the rabbit showing no adverse effect.
The normal treatment procedure of syphilis at the time involved two to four years routine injection with mercury. Ehrlich, after receiving this information, performed experiments on human patients with the same success. After convincing clinical trials, the compound number 606 was given the trade name "Salvarsan", a portmanteau for "saving arsenic". Salvarsan was commercially introduced in 1910, and in 1913, a less toxic form, "Neosalvarsan" (Compound 914), was released in the market. These drugs became the principal treatments of syphilis until the arrival of penicillin and other novel antibiotics towards the middle of the 20th century.
Ehrlich created the concept of magic bullet based on the development of arsphenamine and introduced the English phrase "magic bullet" in The Harben Lectures for 1907 of the Royal Institute of Public Health at London. However, he had used the German word Zauberkugel in his earlier works on the side-chain theory. The magic bullet became the foundation of modern pharmaceutical research. | 1 | Applied and Interdisciplinary Chemistry |
The program motivates companies to disclose and reduce their environmental impacts by using the power of investors and companies. | 1 | Applied and Interdisciplinary Chemistry |
An osmotic coefficient is a quantity which characterises the deviation of a solvent from ideal behaviour, referenced to Raoult's law. It can be also applied to solutes. Its definition depends on the ways of expressing chemical composition of mixtures.
The osmotic coefficient based on molality m is defined by:
and on a mole fraction basis by:
where is the chemical potential of the pure solvent and is the chemical potential of the solvent in a solution, M is its molar mass, x its mole fraction, R the gas constant and T the temperature in Kelvin. The latter osmotic
coefficient is sometimes called the rational osmotic coefficient. The values for the two definitions are different, but since
the two definitions are similar, and in fact both approach 1 as the concentration goes to zero. | 0 | Theoretical and Fundamental Chemistry |
A nested gene is a gene whose entire coding sequence lies within the bounds (between the start codon and the stop codon) of a larger external gene. The coding sequence for a nested gene differs greatly from the coding sequence for its external host gene. Typically, nested genes and their host genes encode functionally unrelated proteins, and have different expression patterns in an organism.
There are two categories of nested genes:
* genes nested within an intron of a larger gene
* genes which lie opposite the coding sequence of a larger gene | 1 | Applied and Interdisciplinary Chemistry |
The zeroth law of thermodynamics describes thermal equilibrium between thermodynamic systems in form of an equivalence relation. Accordingly, all thermal systems may be divided into a quotient set, denoted as M. If the set M has the cardinality of c, then one can construct an injective function , by which every thermal system has a parameter associated with it such that when two thermal systems have the same value of that parameter, they are in thermal equilibrium. This parameter is the property of temperature. The specific way of assigning numerical values for temperature is establishing a scale of temperature. In practical terms, a temperature scale is always based on usually a single physical property of a simple thermodynamic system, called a thermometer, that defines a scaling function for mapping the temperature to the measurable thermometric parameter. Such temperature scales that are purely based on measurement are called empirical temperature scales.
The second law of thermodynamics provides a fundamental, natural definition of thermodynamic temperature starting with a null point of absolute zero. A scale for thermodynamic temperature is established similarly to the empirical temperature scales, however, needing only one additional fixing point. | 0 | Theoretical and Fundamental Chemistry |
Wood-tar creosote is to some extent used for wood preservation, but it is generally mixed with coal-tar creosote, since the former is not as effective. Commercially available preparations of "liquid smoke", marketed to add a smoked flavour to meat and aid as a preservative, consist primarily of creosote and other constituents of smoke. Creosote is the ingredient that gives liquid smoke its function; guaicol lends to the taste and the creosote oils help act as the preservative. Creosote can be destroyed by treatment with chlorine, either sodium hypochlorite, or calcium hypochlorite solutions. The phenol ring is essentially opened, and the molecule is then subject to normal digestion and normal respiration. | 0 | Theoretical and Fundamental Chemistry |
The anodized aluminium layer is created by passing a direct current through an electrolytic solution, with the aluminium object serving as the anode (the positive electrode in an electrolytic cell). The current releases hydrogen at the cathode (the negative electrode) and oxygen at the surface of the aluminium anode, creating a build-up of aluminium oxide. Alternating current and pulsed current is also possible but rarely used. The voltage required by various solutions may range from 1 to 300 V DC, although most fall in the range of 15 to 21 V. Higher voltages are typically required for thicker coatings formed in sulfuric and organic acid. The anodizing current varies with the area of aluminium being anodized and typically ranges from 30 to 300 A/m.
Aluminium anodizing (eloxal or Electrolytic Oxidation of Aluminium) is usually performed in an acidic solution, typically sulphuric acid or chromic acid, which slowly dissolves the aluminium oxide. The acid action is balanced with the oxidation rate to form a coating with nanopores, 10–150 nm in diameter. These pores are what allow the electrolyte solution and current to reach the aluminium substrate and continue growing the coating to greater thickness beyond what is produced by auto-passivation. These pores allow for the dye to be absorbed, however, this must be followed by sealing or the dye will not stay. Dye is typically followed up by a clean nickel acetate seal. Because the dye is only superficial, the underlying oxide may continue to provide corrosion protection even if minor wear and scratches break through the dyed layer.
Conditions such as electrolyte concentration, acidity, solution temperature, and current must be controlled to allow the formation of a consistent oxide layer. Harder, thicker films tend to be produced by more concentrated solutions at lower temperatures with higher voltages and currents. The film thickness can range from under 0.5 micrometres for bright decorative work up to 150 micrometres for architectural applications. | 1 | Applied and Interdisciplinary Chemistry |
Cohen was born in Boston, the son of a furrier from England, and was the first in his family with a college education. He graduated from Tufts University in 1951. He was guided towards science instead of medicine in a chance encounter with Isaac Asimov while working a summer job as a waiter, and completed his Ph.D. at the University of Southern California in 1955, helping to support his graduate studies by working as an extra in the movies of Katharine Hepburn and Spencer Tracy. His doctoral research, supervised by Jerome A. Berson, concerned the synthesis of alkaloids found in ipecac, and the chemical properties of pyridines.
After postdoctoral research as a Fulbright scholar at the University of Glasgow, working with Derek Barton, he joined the University of Pittsburgh chemistry faculty in 1956, and became one of the first professors at the university to bring in federal grant money for his research. He retired as a professor emeritus in 1999, but continued to do research in his laboratory, often working 80-hour weeks.
At the University of Pittsburgh, he was the doctoral advisor to over 40 students. | 0 | Theoretical and Fundamental Chemistry |
In eukaryotes, oxidative phosphorylation occurs in the mitochondrial cristae. It comprises the electron transport chain that establishes a proton gradient (chemiosmotic potential) across the boundary of the inner membrane by oxidizing the NADH produced from the Krebs cycle. ATP is synthesized by the ATP synthase enzyme when the chemiosmotic gradient is used to drive the phosphorylation of ADP. The electrons are finally transferred to exogenous oxygen and, with the addition of two protons, water is formed. | 1 | Applied and Interdisciplinary Chemistry |
The "strain energy" of a molecule is a quantity that is difficult to precisely define, so the meaning of this term can easily vary depending on one's interpretation. Instead, an objective way to view the allylic strain of a molecule is through its conformational equilibrium. Comparing the heats of formation of the involved conformers, an overall ΔH can be evaluated. This term gives information about the relative stabilities of the involved conformers and the effect allylic strain has one equilibrium. Heats of formation can be determined experimentally though calorimetric studies; however, calculated enthalpies are more commonly used due to the greater ease of acquisition.
Different methods utilized to estimate conformational equilibrium enthalpy include: the Westheimer method, the homomorph method, and more simply—using estimated enthalpies of nonbonded interactions within a molecule. Because all of these methods are approximations, reported strain values for the same molecule can vary and should be used only to give a general idea of the strain energy. | 0 | Theoretical and Fundamental Chemistry |
Atomization and Sprays is an international peer-reviewed scientific journal published monthly by Begell House. Founded by Norman Chigier in 1991, it presents original archival-quality research on the physical structure of liquids undergoing breakup and on their interaction with gaseous flow and solid surfaces. Currently it is the only journal that focuses exclusively on atomization and sprays, covering work on theoretical, computational and experimental aspects of the subject.
The journal is the integral hub for a community of industrialists, researchers, academics and students engaged in professional activities related to the spraying of liquids. Members of this community meet regularly around the world at conferences organised by The Institute for Liquid Atomization and Spray Systems (ILASS), which comprises ILASS-America, ILASS-Europe, ILASS-Japan, ILASS-Korea and ILASS-Taiwan.
The editor-in-chief is Editor-in-Chief Europe: GÜNTER BRENN, Editor-in-Chief Americas: Marcus Herrmann for America, and Editor-in-Chief Asia: David Hung. | 1 | Applied and Interdisciplinary Chemistry |
Unimolecular ion decomposition is the fragmentation of a gas phase ion in a reaction with a molecularity of one. Ions with sufficient internal energy may fragment in a mass spectrometer, which in some cases may degrade the mass spectrometer performance, but in other cases, such as tandem mass spectrometry, the fragmentation can reveal information about the structure of the ion. | 0 | Theoretical and Fundamental Chemistry |
The exact timing at which life emerged on Earth is unknown. Minimum age estimates are based on evidence from the geologic rock record. The earliest physical evidence of life so far found consists of microbialites in the Nuvvuagittuq Greenstone Belt of Northern Quebec, in banded iron formation rocks at least 3.77 and possibly as old as 4.32 Gya. The micro-organisms lived within hydrothermal vent precipitates, soon after the 4.4 Gya formation of oceans during the Hadean. The microbes resembled modern hydrothermal vent bacteria, supporting the view that abiogenesis began in such an environment.
Biogenic graphite has been found in 3.7 Gya metasedimentary rocks from southwestern Greenland and in microbial mat fossils from 3.49 Gya cherts in the Pilbara region of Western Australia. Evidence of early life in rocks from Akilia Island, near the Isua supracrustal belt in southwestern Greenland, dating to 3.7 Gya, have shown biogenic carbon isotopes. In other parts of the Isua supracrustal belt, graphite inclusions trapped within garnet crystals are connected to the other elements of life: oxygen, nitrogen, and possibly phosphorus in the form of phosphate, providing further evidence for life 3.7 Gya. In the Pilbara region of Western Australia, compelling evidence of early life was found in pyrite-bearing sandstone in a fossilized beach, with rounded tubular cells that oxidized sulfur by photosynthesis in the absence of oxygen. Carbon isotope ratios on graphite inclusions from the Jack Hills zircons suggest that life could have existed on Earth from 4.1 Gya.
The Pilbara region of Western Australia contains the Dresser Formation with rocks 3.48 Gya, including layered structures called stromatolites. Their modern counterparts are created by photosynthetic micro-organisms including cyanobacteria. These lie within undeformed hydrothermal-sedimentary strata; their texture indicates a biogenic origin. Parts of the Dresser formation preserve hot springs on land, but other regions seem to have been shallow seas. A molecular clock analysis suggests the LUCA emerged prior to the Late Heavy Bombardment (3.9 Gya). | 0 | Theoretical and Fundamental Chemistry |
Depending on the type of ligand a co-receptor binds, its location and function can vary. Various ligands include interleukins, neurotrophic factors, fibroblast growth factors, transforming growth factors, vascular endothelial growth factors and epidermal growth factors. Co-receptors prominent in embryonic tissue have an essential role in morphogen gradient formation or tissue differentiation. Co-receptors localized in endothelial cells function to enhance cell proliferation and cell migration.
With such variety in regards to location, co-receptors can participate in many different cellular activities. Co-receptors have been identified as participants in cell signalling cascades, embryonic development, cell adhesion regulation, gradient formation, tissue proliferation and migration. | 1 | Applied and Interdisciplinary Chemistry |
According to the Egyptologist Wallis Budge, the Arabic word al-kīmiyaʾ actually means "the Egyptian [science]", borrowing from the Coptic word for "Egypt", kēme (or its equivalent in the Mediaeval Bohairic dialect of Coptic, khēme). This Coptic word derives from Demotic kmỉ, itself from ancient Egyptian kmt. The ancient Egyptian word referred to both the country and the colour "black" (Egypt was the "Black Land", by contrast with the "Red Land", the surrounding desert); so this etymology could also explain the nickname "Egyptian black arts". However, according to Mahn, this theory may be an example of folk etymology. Assuming an Egyptian origin, chemistry is defined as follows:
:Chemistry, from the ancient Egyptian word "khēmia" meaning transmutation of earth, is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals.
Thus, according to Budge and others, chemistry derives from an Egyptian word khemein or khēmia, "preparation of black powder", ultimately derived from the name khem, Egypt. A decree of Diocletian, written about 300 AD in Greek, speaks against "the ancient writings of the Egyptians, which treat of the khēmia transmutation of gold and silver". | 1 | Applied and Interdisciplinary Chemistry |
To insert a mutation into a DNA sequence, a specific primer is designed. The primer may contain a single substitution or contain a new sequence at its 5 end. If a deletion is required, a sequence that is 5 of the deletion is added, because the 3' end of the primer must have complementarity to the template strand so that the primer can sufficiently anneal to the template DNA.
Following annealing of the primer to the template, DNA replication proceeds to the end of the template. The duplex is denatured and the second primer anneals to the newly formed DNA strand, containing sequence from the first primer. Replication proceeds to produce a strand of the required sequence, containing the mutation.
The duplex is denatured again and the first primer can now bind to the latest DNA strand. The replication reaction continues to produce a fully dimerised DNA fragment. After further PCR cycles, to amplify the DNA, the sample can be separated by agarose gel electrophoresis, followed by electroelution for collection.
Efficiently generating oligonucleotides beyond ~110 nucleotides in length is very difficult, so to insert a mutation further into a sequence than a 110 nt primer will allow, it is necessary to employ overlap extension PCR. In OE-PCR the sequence being modified is used to make two modified strands with the mutation at opposite ends, using the technique described above. After mixing and denaturation, the strands are allowed to anneal to produce three different combinations as detailed in the diagram. Only the duplex without overlap at the 5 end will allow extension by DNA polymerase in 3 to 5' direction.
Following the extension of the OE-PCR reaction, the PCR mix or the eluted fragments of appropriate size are subject to normal PCR, using the outermost primers used in the initial, mutagenic PCR reactions.
In addition, the combination of OE-PCR and asymmetric PCR could be used to improved the efficiency of site-directed mutagenesis. | 1 | Applied and Interdisciplinary Chemistry |
Monosaccharides (from Greek monos: single, sacchar: sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built. Simply, this is the structural unit of carbohydrates.
They are usually colorless, water-soluble, and crystalline organic solids. Contrary to their name (sugars), only some monosaccharides have a sweet taste. Most monosaccharides have the formula (CHO) (though not all molecules with this formula are monosaccharides).
Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose. Monosaccharides are the building blocks of disaccharides (such as sucrose, lactose and maltose) and polysaccharides (such as cellulose and starch). The table sugar used in everyday vernacular is itself a disaccharide sucrose comprising one molecule of each of the two monosaccharides -glucose and -fructose.
Each carbon atom that supports a hydroxyl group is chiral, except those at the end of the chain. This gives rise to a number of isomeric forms, all with the same chemical formula. For instance, galactose and glucose are both aldohexoses, but have different physical structures and chemical properties.
The monosaccharide glucose plays a pivotal role in metabolism, where the chemical energy is extracted through glycolysis and the citric acid cycle to provide energy to living organisms. Maltose is the dehydration condensate of two glucose molecules. | 0 | Theoretical and Fundamental Chemistry |
Alpha-thujaplicinol, an isomer of thujaplicinol, is often encountered in the Asian species of Thujopsis dolabrata, and exhibits high antibacterial and antifungal activities. It has been found to be effective against Enterococcus faecalis and Legionella pneumophila, even at low inhibitory concentrations (1.56 to 50 mg/ml).
In a 2004 study, α-thujaplicinol showed to have high cytotoxic effects upon several cancer cell lines, such as human stomach cancer and murine lymphocytic leukemia.
The other isomer of the compound is called β-thujaplicinol. A recent study found out that it inhibited the development of hepatocellular carcinoma cells because it triggered the autophagic cell death and a subsequent apoptosis.
Earlier studies have shown that β-thujaplicinol can addiotionally suppress estrogen-dependent breast cancer by regulating the estrogen receptor signaling. | 1 | Applied and Interdisciplinary Chemistry |
The hydraulic gradient is a vector gradient between two or more hydraulic head measurements over the length of the flow path. For groundwater, it is also called the Darcy slope, since it determines the quantity of a Darcy flux or discharge. It also has applications in open-channel flow where it is also known as stream gradient and can be used to determine whether a reach is gaining or losing energy. A dimensionless hydraulic gradient can be calculated between two points with known head values as:
where
* is the hydraulic gradient (dimensionless),
* is the difference between two hydraulic heads (length, usually in m or ft), and
* is the flow path length between the two piezometers (length, usually in m or ft)
The hydraulic gradient can be expressed in vector notation, using the del operator. This requires a hydraulic head field, which can be practically obtained only from numerical models, such as MODFLOW for groundwater or standard step or HEC-RAS for open channels. In Cartesian coordinates, this can be expressed as:
This vector describes the direction of the groundwater flow, where negative values indicate flow along the dimension, and zero indicates no flow. As with any other example in physics, energy must flow from high to low, which is why the flow is in the negative gradient. This vector can be used in conjunction with Darcy's law and a tensor of hydraulic conductivity to determine the flux of water in three dimensions. | 1 | Applied and Interdisciplinary Chemistry |
Lutathera is a peptide receptor radioligand/radionuclide therapy (approved by the FDA in 2018) specifically for patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) that have somatostatin hormone receptors (SSTR). The radioisotope is Lu-177 and the ligand is a SSTR on the surface of tumor cells.
Lu-177 is produced by bombarding the stable isotope Yb-176 (which is found in monazite sand as well as the ores euxenite and xenotime) with neutrons. Yb-176 turns into Yb-177 which is unstable and has a half life of 1.9 hours so it quickly decays into the medical isotope Lu-177. For mass production, it is better to produce Yb-176 through fission reactors. This is the indirect production method and requires elaborate radiochemical separation, purification, and results in large amounts of radioactive waste. The direct method of producing Lu-177 is by performing neutron irradiation on Lu-176 to Lu-177. This is an inexpensive and effective method to produce Lu-177. In the United States, the main place that Lu-177 is produced is the University of Missouri Research Reactor.
Once produced, Lu-177 is stable for 72 hours if stored below room temperature. Freeze dried kits of Lutathera do show reduced effectiveness in radiation therapy but they maintain radiochemical purity. Lu-177 requires radiation shielding for handling. Lu-177 is stored and transported in a vial with lead/plexiglass shielding ready-to-use. Repeated production, timely delivery, and quick administration are important so that the therapy remains effective.
Once transported to the hospital or cancer treatment / oncology center, the patient is prepped, all necessary tests are done, and the patient requires two separate IV sites for infusion. One site for radioactive Lu-177 infusion and one site for amino acid infusion. Amino acid infusion is needed to reduce radiation toxicity to the organs - specifically the kidneys. The sites are separate to prevent radioactive contamination after therapy. The patient receives therapy by automated syringe, infusion pump, or gravity using long/short needles, tubing, and sodium chloride solution. Antiemetic (anti-nausea) medications or short/long acting octreotide (cancer growth control) can be used post-therapy for symptom management.
The most common side effects include decreased blood cell counts, increased liver enzymes, vomiting, nausea, increased blood glucose, and decreased blood potassium levels. Lutathera is not given to pregnant or breastfeeding individuals. The therapy shrinks tumors by an average of 30%, reduces disease progression by 72%, and delays the growth of tumors. | 1 | Applied and Interdisciplinary Chemistry |
There are twenty-one species currently classified under Ancyronyx. Eleven of these are endemic to the Philippines, which may indicate that the country is a center of diversity for the genus. Most of the species have highly restricted distributions, often being found in only one island.
*Ancyronyx acaroides – Southeast Asia
**Ancyronyx acaroides acaroides – Myanmar, Vietnam, Malaysia (peninsular Malaysia, Borneo), Brunei, Indonesia (Sumatra, Java)
**Ancyronyx acaroides cursor – Indonesia (Bali)
*Ancyronyx buhid – Philippines (Mindoro)
*Ancyronyx helgeschneideri – Philippines (Palawan, Busuanga)
*Ancyronyx hjarnei – Indonesia (Sulawesi)
*Ancyronyx jaechi – Sri Lanka
*Ancyronyx johanni – Indonesia (Siberut)
*Ancyronyx malickyi – Laos, southern Thailand, Malaysia (peninsular Malaysia, Borneo), Indonesia (Sumatra)
*Ancyronyx minerva – Philippines (Palawan, Busuanga, Mindoro)
*Ancyronyx minutulus – Philippines (Palawan)
*Ancyronyx montanus – Philippines (Palawan)
*Ancyronyx patrolus – Philippines (Palawan, Busuanga)
*Ancyronyx procerus – Vietnam, Malaysia (Borneo), Brunei, Philippines (Busuanga)
*Ancyronyx pseudopatrolus – Philippines (Palawan)
*Ancyronyx punkti – Philippines (Palawan)
*Ancyronyx raffaelacatharina – Indonesia (Sulawesi)
*Ancyronyx sarawacensis – Malaysia (Borneo)
*Ancyronyx schillhammeri – Philippines (Mindoro)
*Ancyronyx sophiemarie – Philippines (Sibuyan)
*Ancyronyx tamaraw – Philippines (Mindoro)
*Ancyronyx variegatus – United States of America
*Ancyronyx yunju – China (Jiangxi) | 1 | Applied and Interdisciplinary Chemistry |
When certain liquids needs to be purified, siphoning can help prevent either the bottom (dregs) or the top (foam and floaties) from being transferred out of one container into a new container. Siphoning is thus useful in the fermentation of wine and beer for this reason, since it can keep unwanted impurities out of the new container.
Self-constructed siphons, made of pipes or tubes, can be used to evacuate water from cellars after floodings. Between the flooded cellar and a deeper place outside a connection is built, using a tube or some pipes. They are filled with water through an intake valve (at the highest end of the construction). When the ends are opened, the water flows through the pipe into the sewer or the river.
Siphoning is common in irrigated fields to transfer a controlled amount of water from a ditch, over the ditch wall, into furrows.
Large siphons may be used in municipal waterworks and industry. Their size requires control via valves at the intake, outlet and crest of the siphon. The siphon may be primed by closing the intake and outlets and filling the siphon at the crest. If intakes and outlets are submerged, a vacuum pump may be applied at the crest to prime the siphon. Alternatively the siphon may be primed by a pump at either the intake or outlet. Gas in the liquid is a concern in large siphons. The gas tends to accumulate at the crest and if enough accumulates to break the flow of liquid, the siphon stops working. The siphon itself will exacerbate the problem because as the liquid is raised through the siphon, the pressure drops, causing dissolved gases within the liquid to come out of solution. Higher temperature accelerates the release of gas from liquids so maintaining a constant, low temperature helps. The longer the liquid is in the siphon, the more gas is released, so a shorter siphon overall helps. Local high points will trap gas so the intake and outlet legs should have continuous slopes without intermediate high points. The flow of the liquid moves bubbles thus the intake leg can have a shallow slope as the flow will push the gas bubbles to the crest. Conversely, the outlet leg needs to have a steep slope to allow the bubbles to move against the liquid flow; though other designs call for a shallow slope in the outlet leg as well to allow the bubbles to be carried out of the siphon. At the crest the gas can be trapped in a chamber above the crest. The chamber needs to be occasionally primed again with liquid to remove the gas. | 1 | Applied and Interdisciplinary Chemistry |
In a screen with replicates, we can directly estimate data variability for each compound, and thus we can use more powerful methods, such as SSMD for cases with replicates and t-statistic that does not rely on the strong assumption that the z-score and z*-score rely on. One issue with the use of t-statistic and associated p-values is that they are affected by both sample size and effect size. They come from testing for no mean difference, thus are not designed to measure the size of small molecule or siRNA effects. For hit selection, the major interest is the size of effect in a tested small molecule or siRNA. SSMD directly assesses the size of effects. SSMD has also been shown to be better than other commonly used effect sizes. The population value of SSMD is comparable across experiments and thus we can use the same cutoff for the population value of SSMD to measure the size of siRNA effects.
SSMD can overcome the drawback of average fold change not being able to capture data variability. On the other hand, because SSMD is the ratio of mean to standard deviation, we may get a large SSMD value when the standard deviation is very small, even if the mean is small. In some cases, a too small mean value may not have a biological impact. As such, the compounds with large SSMD values (or differentiations) but too small mean values may not be of interest. The concept of dual-flashlight plot has been proposed to address this issue. In a dual-flashlight plot, we plot the SSMD versus average log fold-change (or average percent inhibition/activation) on the y- and x-axes, respectively, for all compounds investigated in an experiment. With the dual-flashlight plot, we can see how the genes or compounds are distributed into each category in effect sizes, as shown in the figure. Meanwhile, we can also see the average fold-change for each compound. | 1 | Applied and Interdisciplinary Chemistry |
Storm water runoff in a combined sewer produces a first foul flush with a suspension of accumulated sanitary solids from the sewer in addition to pollutants from surface runoff. Inflow may produce a foul flush effect in sanitary sewers if flows peak during wet weather. As flow rates increase above average, a relatively small percentage of the total flow contains a disproportionately large percentage of the total pollutant mass associated with overall flow volume through the peak flow event. Sewer solids deposition during low flow periods and subsequent resuspension during peak flow events is the major pollutant source for the first-flush combined-sewer overflow (CSO) phenomenon.
Sanitary sewage solids can either go through the system or settle out in laminar flow portions of the sewer to be available for washout during peak flows. The wetted perimeter of sewers may also be colonized by biofilm nourished by soluble sanitary wastes. Hydraulic design is the underlying reason for solids deposition in sewers. Combined sewers sized for peak runoff events expected once a decade can carry up to 1,000 times the average sanitary flow. Less dramatically oversized sewers are common in new developments and near the upstream end of collection systems. Suspended solids may accumulate when low-flow fluid velocities generate insufficient turbulence. Solids deposition is greatest where velocities are low during dry weather. In large combined sewers it may be impossible to attain sanitary sewage velocities generating sufficient turbulence to keep solids suspended during dry weather.
Biofilm and previously deposited solids may be scoured and re-entrained during peak flow turbulence. The high pollution load in wastewater at the beginning of a runoff event occurs when increased flow rate erodes accumulated sewer sediment. Erosion of sediments in sewers can release pollutants in concentrations exceeding levels found in contributing sources. The initial highly polluting foul flush is released at the start of wet weather flow during speedy erosion of a weak layer of highly concentrated surficial sediment bed-load. When conditions favor dry-weather solids deposition, the first foul flush may contain as much as 30 percent of the annual total suspended solids discharged to a combined sewer system. Combined sewer suspended solids concentrations of several thousand milligrams per liter (mg/L) may be observed during the first foul flush.
Pollutant concentration levels are influenced by the age and condition of the collection system and the amount of infiltration/inflow in comparison to the sanitary flow. Pollutant concentration peaks depend on size and slope of the piping system, time interval between storms, and solids accumulation in the collection system. Steeper sewer gradients and pipe bottom shapes that maintain high velocity flow during low-flow conditions will reduce sediment accumulation in sewers; and periodic sewer flushing of individual lines during dry weather may move accumulated solids to the wastewater treatment plant before stormwater runoff causes simultaneous peak flow in the entire collection system. | 1 | Applied and Interdisciplinary Chemistry |
Passive daytime radiative cooling surfaces can be integrated with solar energy plants, referred to as solar energy–radiative cooling (SE–RC), to improve functionality and performance by preventing solar cells from overheating and thus degrading. Since solar cells have a maximum efficiency of 33.7% (with the average commercial PV panel having a conversion rate around 20%), the majority of absorbed power produces excess heat and increases the operating temperature of the system. Solar cell efficiency declines 0.4-0.5% for every 1ᵒC increase in temperature.
Passive daytime radiative cooling can extend the life of solar cells by lowering the operating temperature of the system. Integrating PDRCs into solar energy systems is also relatively simple, given that "most solar energy harvesting systems have a sky-facing flat plate structural design, which is similar to radiative cooling systems." Integration has been shown to "produce a higher energy gain per unit area" while also increasing the "total useful working time." Integrated systems can mitigate issues of "limited working time and low energy gain" and are "a current research hotspot," as per Ahmed et al.
Methods have been proposed to potentially enhance cooling performance. Lu et al. proposes using a "full-spectrum synergetic management (FSSM) strategy to cool solar cells, which combines radiative cooling and spectral splitting to enhance radiative heat dissipation and reduce the waste heat generated by the absorption of sub-BG photons."
Outdoor tests using various PDRC materials, some more scalable than others, have demonstrated various degrees of cooling power:
* Wang et al. (2021), a periodic pyramid-textured polydimethylsiloxane (PDMS) radiative film, cooled commercial silicon solar cells by over 2 °C.
* Lee et al. (2021), a visibly clear PDRC designed "using a rational design to deploy an optical modulator (n-hexadecane) in aerogel microparticles within a silicone elastomer matrix," cooled commercial silicon solar cells by 7.7 °C on average.
* Tang et al. (2022), nanoporous anodic aluminum oxide film, flatpanel solar cell relative efficiency improvement of ~2.72%, concentrated solar cell relative efficiency improvement of ~16.02%, described as "a high-performance and scalable radiative cooler."
* Zhao et al. (2022), a silica micro-grating photonic cooler, cooled commercial silicon cells by 3.6 °C under solar intensity of 830 W m to 990 W m. | 0 | Theoretical and Fundamental Chemistry |
Preparation of the diluted acid can be dangerous due to the heat released in the dilution process. To avoid splattering, the concentrated acid is usually added to water and not the other way around. A saying used to remember this is "Do like you oughta, add the acid to the water". Water has a higher heat capacity than the acid, and so a vessel of cold water will absorb heat as acid is added.
Also, because the acid is denser than water, it sinks to the bottom. Heat is generated at the interface between acid and water, which is at the bottom of the vessel. Acid will not boil, because of its higher boiling point. Warm water near the interface rises due to convection, which cools the interface, and prevents boiling of either acid or water.
In contrast, addition of water to concentrated sulfuric acid results in a thin layer of water on top of the acid. Heat generated in this thin layer of water can boil, leading to the dispersal of a sulfuric acid aerosol or worse, an explosion.
Preparation of solutions greater than 6 M (35%) in concentration is dangerous, unless the acid is added slowly enough to allow the mixture sufficient time to cool. Otherwise, the heat produced may be sufficient to boil the mixture. Efficient mechanical stirring and external cooling (such as an ice bath) are essential.
Reaction rates double for about every 10-degree Celsius increase in temperature. Therefore, the reaction will become more violent as dilution proceeds, unless the mixture is given time to cool. Adding acid to warm water will cause a violent reaction.
On a laboratory scale, sulfuric acid can be diluted by pouring concentrated acid onto crushed ice made from de-ionized water. The ice melts in an endothermic process while dissolving the acid. The amount of heat needed to melt the ice in this process is greater than the amount of heat evolved by dissolving the acid so the solution remains cold. After all the ice has melted, further dilution can take place using water. | 0 | Theoretical and Fundamental Chemistry |
RIP causes G:C to A:T transition mutations within repeats, however, the mechanism that detects the repeated sequences is unknown. RID is the only known protein essential for RIP. It is a DNA methyltransferease-like protein, that when mutated or knocked out results in loss of RIP. Deletion of the rid homolog in Aspergillus nidulans, dmtA, results in loss of fertility while deletion of the rid homolog in Ascobolus immersens, masc1, results in fertility defects and loss of methylation induced premeiotically (MIP). | 1 | Applied and Interdisciplinary Chemistry |
In genetics, an operon is a functioning unit of DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product. The result of this is that the genes contained in the operon are either expressed together or not at all. Several genes must be co-transcribed to define an operon.
Originally, operons were thought to exist solely in prokaryotes (which includes organelles like plastids that are derived from bacteria), but their discovery in eukaryotes was shown in the early 1990s, and are considered to be rare. In general, expression of prokaryotic operons leads to the generation of polycistronic mRNAs, while eukaryotic operons lead to monocistronic mRNAs.
Operons are also found in viruses such as bacteriophages. For example, T7 phages have two operons. The first operon codes for various products, including a special T7 RNA polymerase which can bind to and transcribe the second operon. The second operon includes a lysis gene meant to cause the host cell to burst. | 1 | Applied and Interdisciplinary Chemistry |
Rhodizonic acid was discovered by Austrian chemist Johann Heller in 1837, by analyzing the products of heating a mixture of potassium carbonate and charcoal. The name comes from Greek (rhodizō, "to tinge red"), on account of the color of its salts. | 0 | Theoretical and Fundamental Chemistry |
To get to the Kuo criterion, the imaginary part is integrated over the domain () . The stream function at the boundaries of the domain is zero, , as already stated in the assumptions. The zonal flow must vanish at the boundaries of the domain. This leads to a constant stream function which is set to zero for convenience.
The first integral can be solved:
So the first integral is equal to zero. This means that the second integral should also be zero, making it possible to solve this integral numerically.
When is zero, we are dealing with a stable amplitude of the solution, this means that the solution is stable. We are looking for un unstable situation, so then should be zero. Since the fraction in front of is non-zero and positive, this leads to the conclusion that should be zero. This leads to the final formulation, the Kuo criterion:
Here, is the mean zonal flow and is the derivative of the planetary vorticity with respect to . | 1 | Applied and Interdisciplinary Chemistry |
The amino radical only exhibits a very low optical absorption in the visible region (λ = 530 nm, ε = ), while its absorption in the UV (<260 nm) is similar to that of OH. Due to this, it is impractical to determine the rate of reaction of the amino radical with organic compounds by following the decay of the amino radical. | 0 | Theoretical and Fundamental Chemistry |
Zooplankton-mediated release of DOC occurs through sloppy feeding, excretion and defecation which can be important energy sources for microbes. Such DOC production is largest during periods with high food concentration and dominance of large zooplankton species. | 1 | Applied and Interdisciplinary Chemistry |
In most organisms, malate dehydrogenase (MDH) exists as a homodimeric molecule and is closely related to lactate dehydrogenase (LDH) in structure. It is a large protein molecule with subunits weighing between 30 and 35 kDa. Based on the amino acid sequences, it seems that MDH has diverged into two main phylogenetic groups that closely resemble either mitochondrial isozymes or cytoplasmic/chloroplast isozymes. Because the sequence identity of malate dehydrogenase in the mitochondria is more closely related to its prokaryotic ancestors in comparison to the cytoplasmic isozyme, the theory that mitochondria and chloroplasts were developed through endosymbiosis is plausible. The amino acid sequences of archaeal MDH are more similar to that of LDH than that of MDH of other organisms. This indicates that there is a possible evolutionary linkage between lactate dehydrogenase and malate dehydrogenase.
Each subunit of the malate dehydrogenase dimer has two distinct domains that vary in structure and functionality. A parallel β-sheet structure makes up the NAD+ binding domain, while four β-sheets and one α-helix comprise the central NAD binding site. The subunits are held together through extensive hydrogen-bonding and hydrophobic interactions.
Malate dehydrogenase has also been shown to have a mobile loop region that plays a crucial role in the enzyme's catalytic activity. Studies have shown that conformational change of this loop region from the open conformation to the closed conformation after binding of substrate enhances MDH catalysis through shielding of substrate and catalytic amino acids from solvent. Studies have also indicated that this loop region is highly conserved in malate dehydrogenase. | 1 | Applied and Interdisciplinary Chemistry |
Polymers come in a wide variety of compositions, and this diversity of chemistry results in wide-ranging embrittlement mechanisms. The most common sources of polymer embrittlement include oxygen in the air, water in liquid or vapor form, ultraviolet radiation from the sun, acids, and organic solvents.
One of the ways these sources alter the mechanical properties of polymers is through chain scission and chain cross-linking. Chain scission occurs when atomic bonds are broken in the main chain, so environments with elements such as solar radiation lead to this form of embrittlement. Chain scission reduces the length of the polymer chains in a material, resulting in a reduction of strength. Chain cross-linking has the opposite effect. An increase in the number of cross-links (due to an oxidative environment for example), results in stronger, less ductile material.
The thermal oxidation of polyethylene provides a quality example of chain scission embrittlement. The random chain scission induced a change from ductile to brittle behavior once the average molar mass of the chains dropped below a critical value. For the polyethylene system, embrittlement occurred when the weight average molar mass fell below 90 kg/mol. The reason for this change was hypothesized to be a reduction of entanglement and an increase in crystallinity. The ductility of polymers is typically a result of their amorphous structure, so an increase in crystallinity makes the polymer more brittle. In the case of polyethylene terephthalate, hydrolysis produces chain scission embrittlement. It has been demonstrated that the degradation of the mechanical properties correlates with the reduction of the mobile amorphous fraction (MAF), and that the ductile-to-brittle transition occurs when the minimum MAF is reached. This supports a micromechanical interpretation of the embrittlement mechanism rather than a molecular interpretation.
The embrittlement of silicone rubber is due to an increase in the amount of chain cross-linking. When silicone rubber is exposed to air at temperatures above oxidative cross-linking reactions occur at methyl side groups along the main chain. These cross-links make the rubber significantly less ductile.
Solvent stress cracking is a significant polymer embrittlement mechanism. It occurs when liquids or gasses are absorbed into the polymer, ultimately swelling the system. The polymer swelling results in less shear flow and an increase in crazing susceptibility. Solvent stress cracking from organic solvents typically results in static fatigue because of the low mobility of fluids. Solvent stress cracking from gasses is more likely to result in greater crazing susceptibility.
Polycarbonate provides a good example of solvent stress cracking. Numerous solvents have been shown to embrittle polycarbonate (i.e. benzene, toluene, acetone) through a similar mechanism. The solvent diffuses into the bulk, swells the polymer, induces crystallization, and ultimately produces interfaces between ordered and disordered regions. These interfaces produce voids and stress fields that can be propagated throughout the material at stresses much lower than the typical tensile strength of the polymer. | 1 | Applied and Interdisciplinary Chemistry |
Sharpless was born April 28, 1941, in Philadelphia, Pennsylvania. His childhood was filled with summers at his family cottage on the Manasquan River in New Jersey. This is where Sharpless developed a love for fishing that he would continue throughout his life, spending summers in college working on fishing boats. He graduated from Friends Central School in 1959, and continued his studies at Dartmouth College, earning an A.B. in 1963. Sharpless originally planned to attend medical school after his undergraduate degree, but his research professor convinced him to continue his education in chemistry. He earned his Ph.D. in Organic Chemistry from Stanford University in 1968 under Eugene van Tamelen. He continued post-doctoral work at Stanford University (1968–1969) with James P. Collman, working on organometallic chemistry. Sharpless then moved to Harvard University (1969–1970), studying enzymology in Konrad E. Blochs lab. | 0 | Theoretical and Fundamental Chemistry |
Hellers letter was forwarded by Eleanor Roosevelt to FBI director J. Edgar Hoover, who in turn consulted with the director of the alien enemy control unit. This resulted in Hansgirg being released under parole by Theodore Dreier, the treasurer of Black Mountain College, a progressive experimental educational community in North Carolina. Hansgirg was appointed as chemistry professor to replace Charles Lindsley, who took a position with the US department of defense doing research for the war department in 1942. This decision was taken on the advice of Austrian scientist Karl Terzaghi. Hansgirgs parolee sponsorship was transferred in 1943 to Dr. W. R. Wunsch, another employee at Black Mountain College, and then to Isaac Van Horn in July 1944.
At Black Mountain College, Hansgirg combined teaching of chemistry and physics with research and business activities. In 1943, an extension was added to the schools science building to make room for a photography darkroom and for Hansgirgs experiments in extracting magnesium from olivine, a locally abundant mineral. Later in the same year, he developed a modified method of magnesium production that used calcium carbide as a reducing agent. Hansgirg created and applied for patents under the name of the North Carolina Magnesium Development Corporation, and gave 20% of the shares of this business to the college.
Although many of his colleagues had fled Europe during the rise of fascism, Hansgirg was the only Black Mountain College community member with "enemy alien" status. He was known for letting the college community use his grand piano, his organ, his photographic equipment and his extensive collection of opera recordings. He was also one of the few faculty with personal wealth, and provided champagne and strawberries for special celebrations.
In September 1948, the building that housed Hansgirgs equipment and experiments burned down in a fire rumored to have been the result of a fellow faculty members vodka still. | 0 | Theoretical and Fundamental Chemistry |
The Molecular Ancestry Network (MANET) database is a bioinformatics database that maps evolutionary relationships of protein architectures directly onto biological networks. It was originally developed by Hee Shin Kim, Jay E. Mittenthal and Gustavo Caetano-Anolles in the Department of Crop Sciences of the University of Illinois at Urbana-Champaign.
MANET traces for example the ancestry of individual metabolic enzymes in metabolism with bioinformatic, phylogenetic, and statistical methods. MANET currently links information in the Structural Classification of Proteins (SCOP) database, the metabolic pathways database of the Kyoto Encyclopedia of Genes and Genomes (KEGG), and phylogenetic reconstructions describing the evolution of protein fold architecture at a universal level. The database has been updated to reflect evolution of metabolism at the level of protein fold families. MANET literally "paints" the ancestries of enzymes derived from rooted phylogenetic trees directly onto over one hundred metabolic pathways representations, paying homage to one of the fathers of impressionism. It also provides numerous functionalities that enable searching specific protein folds with defined ancestry values, displaying the distribution of enzymes that are painted, and exploring quantitative details describing individual protein folds. This permits the study of global and local metabolic network architectures, and the extraction of evolutionary patterns at global and local levels.
A statistical analysis of the data in MANET showed for example a patchy distribution of ancestry values assigned to protein folds in each subnetwork, indicating that evolution of metabolism occurred globally by widespread recruitment of enzymes. MANET was used recently to sort out enzymatic recruitment processes in metabolic networks and propose that modern metabolism originated in the purine nucleotide metabolic subnetwork. The database is useful for the study of metabolic evolution. | 1 | Applied and Interdisciplinary Chemistry |
Spin-polarized electron energy loss spectroscopy or SPEELS is a technique that is mainly used to measure the dispersion relation of the collective excitations, over the whole Brillouin zone.
Spin waves are collective perturbations in a magnetic solid. Their properties depend on their wavelength (or wave vector). For long wavelength (short wave vector) spin wave the resulting spin precession has a very low frequency and the spin waves can be treated classically. Ferromagnetic resonance (FMR) and Brillouin light scattering (BLS) experiments provide information about the long wavelength spin waves in ultrathin magnetic films and nanostructures. If the wavelength is comparable to the lattice constant, the spin waves are governed by the microscopic exchange coupling and a quantum mechanical description is needed. Therefore, experimental information on these short wavelength (large wave vector) spin waves in ultrathin films is highly desired and may lead to fundamentally new insights into the spin dynamics in reduced dimensions in the future.
SPEELS is the one of the few techniques that can be used to measure the dispersion of such short wavelength spin waves in ultrathin films and nanostructures. | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry, ethenolysis is a chemical process in which internal olefins are degraded using ethylene () as the reagent. The reaction is an example of cross metathesis. The utility of the reaction is driven by the low cost of ethylene as a reagent and its selectivity. It produces compounds with terminal alkene functional groups (α-olefins), which are more amenable to other reactions such as polymerization and hydroformylation.
The general reaction equation is:
Ethenolysis is a form of methylenation, i.e., the installation of methylene () groups. | 0 | Theoretical and Fundamental Chemistry |
Cymene describes organic compounds with the formula . Three isomers exist: 1,2- 1,3-, and 1,4-. All are colorless liquids, immiscible in water, with similar boiling points. They are classified are aromatic hydrocarbons. The bearing two substituents: an isopropyl () group and a methyl group. | 0 | Theoretical and Fundamental Chemistry |
*2009 – Our Women, Our State (Queensland Government) – Highly Commended
*2011 – Leighton Medal of the Royal Australian Chemical Institute, in recognition of her contributions and leadership to the chemistry community, within Australia and overseas.
*2013 – Distinguished Woman in Chemistry or Chemical Engineering award of the International Union of Pure and Applied Chemistry
*2014 – named as one of "175 Faces of Chemistry" by the Royal Society of Chemistry, UK
*2017 – inaugural Margaret Sheil Women in Chemistry Leadership award of the Royal Australian Chemical Institute
*2018 - Royal Society of Chemistry, Australasian lecturer (by invitation)
*2019 – Member of the Order of Australia (AM) in the Australia Day Honours for "significant service to education, particularly to organic chemistry, and as an advocate for women in science".
*2023 - named as a Distinguished Fellow of the Royal Australian Chemical Institute
A species of marine flatworm, discovered at Heron Island, is named for her Maritigrella marygarsonae. | 0 | Theoretical and Fundamental Chemistry |
Duplex stainless steel is widely used in industry because it possesses excellent oxidation resistance, but it can have limited toughness due to its large ferritic grain size and embrittlement tendencies at temperatures ranging from 280–500 °C, especially at 475 °C, where spinodal decomposition of the supersaturated solid ferrite solution into Fe-rich nanophase () and Cr-rich nanophase (), accompanied by G-phase precipitation, occurs, which makes the ferrite phase a preferential initiation site for micro-cracks. | 1 | Applied and Interdisciplinary Chemistry |
The specific molecular mechanism of action of the ywIE protein is currently unknown. However, YwIE is believed to dephosphorylate phosphoarginine residues using a concerted, 2-step process via SN2 reactions. Step 1 involves a nucleophilic attack of Cys7 on the phosphorus atom of the phosphoric group. Then a thiophosphate intermediate is formed. In the second step, a phosphorylation-enzyme intermediate is hydrolyzed following the deprotonation of a water molecule by Asp118. Fuhrmann et al. (2016) believe that Asp118 likely promotes the reaction through the stabilization of the positive charge of the amino group via electrostatic interaction.
Sample general dephosphorylation reaction equation: | 1 | Applied and Interdisciplinary Chemistry |
The total average energy per unit time radiated by Earth is equal to the average energy flux j times the surface area 4πR, where R is Earths radius. On the other hand, the average energy flux absorbed from sunlight is the solar constant S times Earths cross section of πR, times the fraction absorbed by Earth, which is one minus Earths albedo a'.
The average energy per unit time radiated out is equal to the average energy per unit time absorbed from sunlight, so:
giving:
Based on the value of 3.1 W/m^2 obtained above in the section on the one layer model, the radiative forcing due to CO relative to the average radiated flux is therefore:
An exact calculation using the MODTRAN model, over all wavelengths and including methane and ozone greenhouse gasses, as shown in the plot above, gives, for tropical latitudes, an outgoing flux 298.645 W/m for current CO levels and 295.286 W/m after CO doubling, i.e. a radiative forcing of 1.1%, under clear sky conditions, as well as a ground temperature of 299.7 K (26.6 Celsius). The radiative forcing is largely similar in different latitudes and under different weather conditions. | 1 | Applied and Interdisciplinary Chemistry |
Isotopic oxygen is incorporated into the body primarily through ingestion at which point it is used in the formation of, for archaeological purposes, bones and teeth. The oxygen is incorporated into the hydroxylcarbonic apatite of bone and tooth enamel.
Bone is continually remodelled throughout the lifetime of an individual. Although the rate of turnover of isotopic oxygen in hydroxyapatite is not fully known, it is assumed to be similar to that of collagen; approximately 10 years. Consequently, should an individual remain in a region for 10 years or longer, the isotopic oxygen ratios in the bone hydroxyapatite would reflect the oxygen ratios present in that region.
Teeth are not subject to continual remodelling and so their isotopic oxygen ratios remain constant from the time of formation. The isotopic oxygen ratios, then, of teeth represent the ratios of the region in which the individual was born and raised. Where deciduous teeth are present, it is also possible to determine the age at which a child was weaned. Breast milk production draws upon the body water of the mother, which has higher levels of O due to the preferential loss of O through sweat, urine, and expired water vapour.
While teeth are more resistant to chemical and physical changes over time, both are subject to post-depositional diagenesis. As such, isotopic analysis makes use of the more resistant phosphate groups, rather than the less abundant hydroxyl group or the more likely diagenetic carbonate groups present. | 0 | Theoretical and Fundamental Chemistry |
Xylene was first isolated and named in 1850 by the French chemist Auguste Cahours (1813–1891), having been discovered as a constituent of wood tar. | 1 | Applied and Interdisciplinary Chemistry |
Garson won a Royal Society postdoctoral fellowship after her PhD, undertaking research in Rome, Italy from 1977 to 1978. She continued her research at New Hall at Cambridge on a college research fellowship from 1978 to 1981. She worked as a medicinal chemist from 1981 to 1983 at Smith Kline and French Research Ltd in Welwyn, England,.
Garson won a Queen Elizabeth II Research Fellowship from James Cook University (1983–1986), based in the Townsville region to research the bioactive organic chemicals in marine organisms. In Townsville, she undertook dive training to study on the Great Barrier Reef. Garson then took a teaching/research position as the first female academic in chemistry at the University of Wollongong, before moving to the University of Queensland as a lecturer in 1990. She was promoted to Senior Lecturer in 1992 and Reader in 1998. She researches and publishes on the structure, biosynthesis and function of natural products, especially those from marine invertebrates and other microorganisms. She also researches the chemistry of South East Asian medicinal plants.
Garson was promoted to Professor in the School of Chemistry and Molecular Biosciences in 2006, and has served as Deputy Head of the School from 2005 to 2009. Since 2021, she is an Emeritus Professor of Chemistry at the university. | 0 | Theoretical and Fundamental Chemistry |
Although most applications of protein-directed DCC to date involved the use of single protein in the DCL, it is possible to identify protein ligands by using multiple proteins simultaneously, as long as a suitable analytical technique is available to detect the protein species that interact with the DCL components. This approach may be used to identify specific inhibitors or broad-spectrum enzyme inhibitors. | 1 | Applied and Interdisciplinary Chemistry |
Isaac Newton has been credited with the first description of conformal interaction observed through the interference phenomenon known as Newton's rings, though it was S. D. Poisson in 1823 who first described the optical characteristics of two identical surfaces in contact. It was not until the 19th century that objects were made of such precision that the binding phenomenon was observed. The clinging together was described as "wringing together", or as "ansprengen" in German. By 1900 optical contact bonding was being employed in the construction of optical prisms, and the following century saw further research into the phenomenon at the same time that ideas of inter-atom interactions were first being studied. | 0 | Theoretical and Fundamental Chemistry |
The FSHR become desensitized when exposed to FSH for some time. A key reaction of this downregulation is the phosphorylation of the intracellular (or cytoplasmic) receptor domain by protein kinases. This process uncouples Gs protein from the FSHR. Another way to desensitize is to uncouple the regulatory and catalytic units of the cAMP system. | 1 | Applied and Interdisciplinary Chemistry |
The Reynolds-averaged Navier–Stokes equations (RANS equations) are time-averaged
equations of motion for fluid flow. The idea behind the equations is Reynolds decomposition, whereby an instantaneous quantity is decomposed into its time-averaged and fluctuating quantities, an idea first proposed by Osborne Reynolds. The RANS equations are primarily used to describe turbulent flows. These equations can be used with approximations based on knowledge of the properties of flow turbulence to give approximate time-averaged solutions to the Navier–Stokes equations.
For a stationary flow of an incompressible Newtonian fluid, these equations can be written in Einstein notation in Cartesian coordinates as:
The left hand side of this equation represents the change in mean momentum of a fluid element owing to the unsteadiness in the mean flow and the convection by the mean flow. This change is balanced by the mean body force, the isotropic stress owing to the mean pressure field, the viscous stresses, and apparent stress owing to the fluctuating velocity field, generally referred to as the Reynolds stress. This nonlinear Reynolds stress term requires additional modeling to close the RANS equation for solving, and has led to the creation of many different turbulence models. The time-average operator is a Reynolds operator. | 1 | Applied and Interdisciplinary Chemistry |
In spectroscopy, oscillator strength is a dimensionless quantity that expresses the probability of absorption or emission of electromagnetic radiation in transitions between energy levels of an atom or molecule. For example, if an emissive state has a small oscillator strength, nonradiative decay will outpace radiative decay. Conversely, "bright" transitions will have large oscillator strengths. The oscillator strength can be thought of as the ratio between the quantum mechanical transition rate and the classical absorption/emission rate of a single electron oscillator with the same frequency as the transition. | 0 | Theoretical and Fundamental Chemistry |
The advent of synchrotron X-ray sources has been beneficial to X-ray topography techniques. Several of the properties of synchrotron radiation are advantageous also for topography applications: The high collimation (more precisely the small angular source size) allows to reach higher geometrical resolution in topographs, even at larger sample-to-detector distances. The continuous wavelength spectrum facilitates white-beam topography. The high beam intensities available at synchrotrons make it possible to investigate small sample volumes, to work at weaker reflections or further off Bragg-conditions (weak beam conditions), and to achieve shorter exposure times. Finally, the discrete time structure of synchrotron radiation permits topographists to use stroboscopic methods to efficiently visualize time-dependent, periodically recurrent structures (such as acoustic waves on crystal surfaces). | 0 | Theoretical and Fundamental Chemistry |
The linear molecular geometry describes the geometry around a central atom bonded to two other atoms (or ligands) placed at a bond angle of 180°. Linear organic molecules, such as acetylene (), are often described by invoking sp orbital hybridization for their carbon centers.
According to the VSEPR model (Valence Shell Electron Pair Repulsion model), linear geometry occurs at central atoms with two bonded atoms and zero or three lone pairs ( or ) in the AXE notation. Neutral molecules with linear geometry include beryllium fluoride () with two single bonds, carbon dioxide () with two double bonds, hydrogen cyanide () with one single and one triple bond. The most important linear molecule with more than three atoms is acetylene (), in which each of its carbon atoms is considered to be a central atom with a single bond to one hydrogen and a triple bond to the other carbon atom. Linear anions include azide () and thiocyanate (), and a linear cation is the nitronium ion ().
Linear geometry also occurs in molecules, such as xenon difluoride () and the triiodide ion () with one iodide bonded to the two others. As described by the VSEPR model, the five valence electron pairs on the central atom form a trigonal bipyramid in which the three lone pairs occupy the less crowded equatorial positions and the two bonded atoms occupy the two axial positions at the opposite ends of an axis, forming a linear molecule. | 0 | Theoretical and Fundamental Chemistry |
*[https://research.bidmc.org/ncfg National Center for Functional Glycomics (NCFG)] The focus of the NCFG is the development in the glycosciences, with an emphasis on exploring the molecular mechanisms of glycan recognition by proteins important in human biology and disease. They have a number of [https://ncfg.hms.harvard.edu/resources resources for glycan analysis] as well as [https://ncfg.hms.harvard.edu/training training in glycomics] and [https://ncfg.hms.harvard.edu/protocols protocols for glycan analysis]
* [https://glytoucan.org/ GlyTouCan], Glycan structure repository
* [http://glycosciences.de/ Glycosciences.DE], German glycan database
* [http://glycoscience.ru Carbohydrate Structure Database], Russian glycan database
* [http://unicarbkb.org UniCarbKB], Australian glycan database
* [https://web.archive.org/web/20130703194144/http://glycosuitedb.expasy.org/glycosuite/glycodb GlycoSuiteDB], glycan database by Swiss Institute of Bioinformatics
* [https://www.glygen.org/ GlyGen], NIH funded glycoinformatics resource
* The Consortium for Functional Glycomics (CFG) is a non-profit research initiative comprising eight core facilities and 500+ [http://www.functionalglycomics.org/glycomics/common/jsp/useraccess/pipeople.jsp participating investigators] that work together to develop [http://www.functionalglycomics.org/static/consortium/resources.shtml resources and services] and make them available to the scientific community free of charge. The data generated by these resources are captured in databases accessible through the [http://www.functionalglycomics.org Functional Glycomics Gateway], a web resource maintained through a partnership between the CFG and Nature Publishing Group.
* [http://dels.nas.edu/Report/Transforming-Glycoscience-Roadmap/13446 Transforming Glycoscience: A Roadmap for the Future] by the U.S. National Research Council. This site provides information about the U.S. National Research Council's reports and workshops on glycoscience. | 0 | Theoretical and Fundamental Chemistry |
The Riemschneider thiocarbamate synthesis converts alkyl or aryl thiocyanates to thiocarbamates under acidic conditions, followed by hydrolysis with ice water. The reaction was discovered by the German chemist in 1951 as a more efficient method to produce thiocarbamates. Some references spell the name Riemenschneider.
The Riemschneider reaction can also be used to create the corresponding N-substituted thiocarbamate from an alcohol or alkene. | 0 | Theoretical and Fundamental Chemistry |
Fibrosis or scar formation is another pro-oxidant-related symptom. E.g., interocular copper or vitreous chalicosis is associated with severe vitreous fibrosis, as is interocular iron. Liver cirrhosis is also a major symptom of Wilson's disease. The pulmonary fibrosis produced by paraquat and the antitumor agent bleomycin is also thought to be induced by the pro-oxidant properties of these agents. It may be that oxidative stress produced by such agents mimics a normal physiological signal for fibroblast conversion to myofibroblasts. | 1 | Applied and Interdisciplinary Chemistry |
Aldol reactions are commonly used in organic chemistry to form carbon-to-carbon bonds. The aldehyde-alcohol motif common to the reaction product is ubiquitous to synthetic chemistry and natural products. The reaction utilizes two carbonyl compounds to generate a β-hydroxy carbonyl. Catalysis is always necessary because the barrier of activation between kinetic products and starting materials makes the dynamic reversible process too slow. Catalysts that have been successfully employed include enzymatic aldolase and AlO based systems. | 0 | Theoretical and Fundamental Chemistry |
* "Sur un élément 87, dérivé de lactinium," Comptes-rendus hebdomadaires des séances de lAcadémie des sciences, 208: 97 (1939).
* "Francium: élément 87," Bulletin de la Société chimique de France, 18: 779 (1951).
* "On the Descendants of Actinium K: 87Ac223," Journal de Physique et le Radium, 17: 545 (1956). | 1 | Applied and Interdisciplinary Chemistry |
Gunzbergs test is a chemical test used for detecting the presence of hydrochloric acid. Gunzbergs reagent is made by dissolving two grams of phloroglucinol and one gram of vanillin in 100 millilitres of 95% ethanol. Hydrochloric acid catalyses Gunzberg's reagent to form a red complex. | 0 | Theoretical and Fundamental Chemistry |
The same process of photoemission can be used to produce electricity from any spectrum, although the number of semiconductor materials that will have just the right bandgap for an arbitrary hot object is limited. Instead, semiconductors that have tuneable bandgaps are needed. It is also difficult to produce solar-like thermal output; an oxyacetylene torch is about 3400 K (~3126 °C), and more common commercial heat sources like coal and natural gas burn at much lower temperatures around 900 °C to about 1300 °C. This further limits the suitable materials. In the case of TPV most research has focused on gallium antimonide (GaSb), although germanium (Ge) is also suitable.
Another problem with lower-temperature sources is that their energy is more spread out, according to Wien's displacement law. While one can make a practical solar cell with a single bandgap tuned to the peak of the spectrum and just ignore the losses in the IR region, doing the same with a lower temperature source will lose much more of the potential energy and result in very low overall efficiency. This means TPV systems almost always use multi-junction cells in order to reach reasonable double-digit efficiencies. Current research in the area aims at increasing system efficiencies while keeping the system cost low, but even then their roles tend to be niches similar to those of multi-junction solar cells. | 0 | Theoretical and Fundamental Chemistry |
The majority of ERVs that occur in vertebrate genomes are ancient, inactivated by mutation, and have reached genetic fixation in their host species. For these reasons, they are extremely unlikely to have negative effects on their hosts except under unusual circumstances. Nevertheless, it is clear from studies in birds and non-human mammal species including mice, cats and koalas, that younger (i.e., more recently integrated) ERVs can be associated with disease. The number of active ERVs in the genome of mammals is negatively related to their body size, suggesting a contribution to Peto's paradox through cancer pathogenesis. This has led researchers to propose a role for ERVs in several forms of human cancer and autoimmune disease, although conclusive evidence is lacking. | 1 | Applied and Interdisciplinary Chemistry |
At high Reynolds numbers, the two-dimensional problem governed by two-dimensional Euler equations reduce to solving a problem for the stream function , which satisfies
where is the only non-zero vorticity component in the -direction of the vorticity vector. As it stands, the problem is ill-posed since the vorticity distribution can have infinite number of possibilities, all of which satisfies the equation and the boundary condition. This is not true if no streamline is closed, in which case, every streamline can be traced back to the boundary where and therefore its corresponding vorticity are prescribed. The difficulty arises only when there are some closed streamlines inside the domain that does not connect to the boundary and one may suppose that at high Reynolds numbers, is not uniquely defined in regions where closed streamlines occur. The Prandtl–Batchelor theorem, however, asserts that this is not the case and is uniquely defined in such cases, through an examination of the limiting process properly.
The steady, non-dimensional vorticity equation in our case reduces to
Integrate the equation over a surface lying entirely in the region where we have closed streamlines, bounded by a closed contour
The integrand in the left-hand side term can be written as since . By divergence theorem, one obtains
where is the outward unit vector normal to the contour line element . The left-hand side integrand can be made zero if the contour is taken to be one of the closed streamlines since then the velocity vector projected normal to the contour will be zero, that is to say . Thus one obtains
This expression is true for finite but large Reynolds number since we did not neglect the viscous term before.
Unlike the two-dimensional inviscid flows, where since with no restrictions on the functional form of , in the viscous flows, . But for large but finite , we can write , and this small corrections become smaller and smaller as we increase the Reynolds number. Thus, in the limit , in the first approximation (neglecting the small corrections), we have
Since is constant for a given streamline, we can take that term outside the integral,
One may notice that the integral is negative of the circulation since
where we used the Stokes theorem for circulation and . Thus, we have
The circulation around those closed streamlines is not zero (unless the velocity at each point of the streamline is zero with a possible discontinuous vorticity jump across the streamline) . The only way the above equation can be satisfied is only if
i.e., vorticity is not changing across these closed streamlines, thus proving the theorem. Of course, the theorem is not valid inside the boundary layer regime. This theorem cannot be derived from the Euler equations. | 1 | Applied and Interdisciplinary Chemistry |
The applications for sol gel-derived products are numerous. For example, scientists have used it to produce the world's lightest materials and also some of its toughest ceramics. | 0 | Theoretical and Fundamental Chemistry |
The most common area denial weapons are land mines of various types, planted by hand or dispersed by artillery. Some modern prototypes experiment with automatic guns or artillery-delivered ammunitions that are fired only after remote sensing detects enemies.
Booby traps or improvised explosive devices in sufficient concentration also qualify as area denial weapons, though they are much easier to clear and usually pose less long-term danger. Temporary area denial can be achieved on a tactical level by artillery barrage.
During an armed conflict there are several methods of countering land mines. These include using armored vehicles to negate the effects of anti-personnel land mines. Land mines can also be cleared either by hand, or by using specialised equipment such as tanks equipped with flails. Explosives can also be used to clear mine fields, either by artillery bombardment, or with specialised charges such as Bangalore torpedoes, the Antipersonnel Obstacle Breaching System and the Python Minefield Breaching System.
156 states are parties to the Ottawa Treaty under which they have agreed not to use, stockpile, produce or transfer anti-personnel mines. | 1 | Applied and Interdisciplinary Chemistry |
In the deformation of solids, surface energy can be treated as the "energy required to create one unit of surface area", and is a function of the difference between the total energies of the system before and after the deformation:
Calculation of surface energy from first principles (for example, density functional theory) is an alternative approach to measurement. Surface energy is estimated from the following variables: width of the d-band, the number of valence d-electrons, and the coordination number of atoms at the surface and in the bulk of the solid. | 0 | Theoretical and Fundamental Chemistry |
Albert is known for his commentary on the musical practice of his times. Most of his written musical observations are found in his commentary on Aristotles Poetics'. He rejected the idea of "music of the spheres" as ridiculous: movement of astronomical bodies, he supposed, is incapable of generating sound. He wrote extensively on proportions in music, and on the three different subjective levels on which plainchant could work on the human soul: purging of the impure; illumination leading to contemplation; and nourishing perfection through contemplation. Of particular interest to 20th-century music theorists is the attention he paid to silence as an integral part of music. | 1 | Applied and Interdisciplinary Chemistry |
The vapor pressure of a liquid, which varies with its temperature, is a measure of how much the vapor of the liquid tends to concentrate in the surrounding atmosphere as the liquid evaporates. Vapor pressure is a major determinant of the flash point and flame point, with higher vapor pressures leading to lower flash points and higher flammability ratings. | 0 | Theoretical and Fundamental Chemistry |
One structural consequence of acyclic systems due to the stereoelectronic effect is the gauche effect. In 1,2-difluoroethane, despite the steric clash, the preferred conformation is the gauche one because σ(C–H) is a good donor and σ*(C–F) is a good acceptor and the stereoelectronic effect (σ(C–H) → σ*(C–F)) requires the energy minimum to be gauche instead of anti.
This gauche effect and its impact on conformation are important in biochemistry. For example, in HIF-α subunit fragments containing (2S,4R)-4-hydroxyproline, the gauche interaction favors the conformer that can bind to the active site of pVHL. pVHL mediates the proteasomal degradation of HIF1A and with that the physiological response to hypoxia. | 0 | Theoretical and Fundamental Chemistry |
Ibrutinib, a covalent inhibitor of Bruton's tyrosine kinase, has been approved for the treatment of chronic lymphocytic leukemia, waldenstrom’s macroglobulinemia and mantle cell lymphoma. | 1 | Applied and Interdisciplinary Chemistry |
Due to the sensitive location of splice sites, mutations in the acceptor or donor areas of splice sites can become detrimental to a human individual. In fact, many different types of diseases stem from anomalies within the splice sites. | 1 | Applied and Interdisciplinary Chemistry |
Sawdust is flammable and accumulations provide a ready source of fuel. Airborne sawdust can be ignited by sparks or even heat accumulation and result in dust fire or explosions. | 1 | Applied and Interdisciplinary Chemistry |
The industrial synthesis entails the reaction of hydrogen chloride with a solution of sulfur trioxide in sulfuric acid:
:HCl + SO → ClSOH
It can also be prepared by chlorination of sulfuric acid, written here for pedagogical purposes as HSO(OH), vs. the usual format HSO:
:PCl + HSO(OH) → HSOCl + POCl + HCl
The latter method is more suited for laboratory-scale operations. | 0 | Theoretical and Fundamental Chemistry |
Despite multiple employment offers on the East Coast of the United States, Young chose to remain in the San Francisco Bay Area for her professional career. From 1995 to 2006, Young worked at Celera Genomics, studying inhibitor compounds of human plasma proteins such as kallikrein and Factors VIIa and IXa. She was recruited to Genentech in 2006, and in 2018 was promoted to Senior Vice President of Small Molecule drug discovery. One of her major research successes was development of a chemistry campaign against Bruton's tyrosine kinase, leading to molecules to potentially treat rheumatoid arthritis and B-cell lymphomas. Her team developed fenebrutinib, currently in Phase II trials for several autoimmune disorders. | 1 | Applied and Interdisciplinary Chemistry |
The McCumber relation is confirmed for various media.
In particular, relation (1) makes it possible to approximate two functions of frequency, emission and absorption cross sections, with single fit | 0 | Theoretical and Fundamental Chemistry |
In industrial water treatment terminology, water quality with high RSC index is synonymous with the soft water but is chemically very different from naturally soft water which has a very low ionic concentration. When calcium and magnesium salts are present in dissolved form in water, these salts precipitate on the heat transfer surfaces forming insulating hard scaling / coating which reduces the heat transfer efficiency of the heat exchangers. To avoid scaling in water cooled heat exchangers, water is treated by lime and or soda ash to remove the water hardness.
The following chemical reactions take place in lime soda softening process which precipitates the calcium and magnesium salts as calcium carbonate and magnesium hydroxide which have very low solubility in water.
* CaSO + NaCO ---> CaCO↓ + NaSO
* CaCl + NaCO ---> CaCO↓ + 2NaCl
* MgSO + Ca(OH) + NaCO ---> Mg(OH)↓ + CaCO↓ + NaSO
* MgCl + Ca(OH) + NaCO ---> Mg(OH)↓ + CaCO↓ + 2NaCl
* 2NaHCO + Ca(OH) ---> CaCO↓ + NaCO + 2HO
* NaCO + Ca(OH) ---> CaCO↓ + 2NaOH
* Ca(HCO) + Ca(OH) ---> 2CaCO↓ + 2HO
* Mg(HCO) + 2Ca(OH) ---> Mg(OH)↓ + 2CaCO↓ + 2HO
* MgCO + Ca(OH) ---> Mg(OH)↓ + CaCO↓
The excess soda ash after precipitating the calcium and magnesium salts is in carbonates & bicarbonates of sodium which imparts high pH or alkalinity to soil water. | 0 | Theoretical and Fundamental Chemistry |
A clinical application of DCS is for use in diagnosis of cancers. An example of this is measuring red blood cell flow in breast tumors. In this experiment, both healthy patients and patients with breast tumors were recruited. Researchers scanned the tumor with a hand-held optical probe with 4 sources and detectors 2.5 cm apart from each other. Then, the resultant correlation functions were fit to the solution of the correlation diffusion equation to obtain the blood flow index. The average relative blood flow was reported at each position. Blood flow increased in both horizontal and vertical scans as the probe crossed over the tumor. These findings were consistent with previous Doppler ultrasound and PET results. | 0 | Theoretical and Fundamental Chemistry |
The Department of Chemical Engineering (DChE) is an academic department operating under the College of Engineering of the University of the Philippines Diliman.
The department was established in 1956 and has an overall 90% passing rate in the licensure examinations held in the Philippines. It also contributes about 10% to 60% of the total number of new chemical engineers in the Philippines every year. | 1 | Applied and Interdisciplinary Chemistry |
* Bangladesh:
** Bengal Police started using pepper spray to control opposition movement.
* China: Forbidden for civilians, it is used only by law enforcement agencies. Underground trade leads to some civilian self-defense use.
** Hong Kong: Forbidden for civilians, it is legal to possess and use only by the members of Disciplined Services when on duty.
*** Such devices are classified as "arms" under the "Laws of Hong Kong". Chap 238 Firearms and Ammunition Ordinance. Without a valid license from the Hong Kong Police Force, it is a crime to possess and can result in a fine of $100,000 and imprisonment for up to 14 years.
* India: Legal
** They are sold via government-approved companies after performing a background verification.
* Indonesia: It is legal, but there are restrictions on its sale and possession.
* Iran: Forbidden for civilians, it is used only by the police.
* Israel: OC and CS spray cans may be purchased by any member of the public without restriction and carried in public.
** In the 1980s, a firearms license was required for doing so, but these sprays have since been deregulated.
* Japan: There are no laws against possession or use, but using it could result in imprisonment, depending on the damage caused to the target.
* Malaysia: Use and possession of pepper spray for self-defense are legal.
* Mongolia: Possession and use for self-defense are legal, and it is freely available in stores.
* Pakistan: Possession and use for self-defense is legal and its available at physical and online stores.
* Philippines: Possession and use for self-defense is legal, and it is freely available in stores.
* Saudi Arabia: Use and possession of pepper spray for self-defense are legal.
** It is an offense to use pepper spray on anyone for reasons other than self-defense.
* Singapore: Travellers are prohibited from bringing pepper spray into the country, and it is illegal for the public to possess it.
* South Korea: Pepper sprays containing OC are legal.
** Requires a permit to distribute, own, carry pepper sprays containing pre-compressed gas or explosive propellent.
** Pepper sprays without any pre-compressed gas or explosive propellent are unrestricted.
* Thailand: Use for self-defense is legal, and it is freely available in stores.
** Possession in a public place can be punished by confiscation and a fine.
* Taiwan: Legal for self-defense, it is available in some shops.
** It is an offense to use pepper spray on anyone for reasons other than self-defense.
* Vietnam: Forbidden for civilians and used only by the police. | 1 | Applied and Interdisciplinary Chemistry |
Photodisintegration (also called phototransmutation) is a similar but different physical process, in which an extremely high energy gamma ray interacts with an atomic nucleus and causes it to enter an excited state, which immediately decays by emitting a subatomic particle. | 0 | Theoretical and Fundamental Chemistry |
Geologists often refer to the temperature range in which oil forms as an "oil window". Below the minimum temperature oil remains trapped in the form of kerogen. Above the maximum temperature the oil is converted to natural gas through the process of thermal cracking. Sometimes, oil formed at extreme depths may migrate and become trapped at a much shallower level. The Athabasca oil sands are one example of this. | 0 | Theoretical and Fundamental Chemistry |
Competitive assays are generally used for smaller analytes since smaller analytes have fewer binding sites. The sample first encounters antibodies to the target analyte labelled with a visual tag (colored particles). The test line contains the target analyte fixed to the surface. When the target analyte is absent from the sample, unbound antibody will bind to these fixed analyte molecules, meaning that a visual marker will show. Conversely, when the target analyte is present in the sample, it binds to the antibodies to prevent them binding to the fixed analyte in the test line, and thus no visual marker shows. This differs from sandwich assays in that no band means the analyte is present. | 1 | Applied and Interdisciplinary Chemistry |
The explorations in the foothills of the Kopetdag revealed well developed irrigation systems with water control arrangements which resulted in prosperous, well settled large regional centres. The largest of these settlements is Namazga-Tepe with an area of 50 ha. The excavations done at this site lead to the discovery of six distinct periods. Named Namazgadepe I to VI, the periods extended over the late 5th millennium to early 3rd millennium BC. In the process of development over these centuries, the transition observed was from Chalcolithic period to Early Bronze Age with urban characteristics in the settlements. Dwelling houses also emerged from chaotically planned one room houses to larger houses with many rooms with the interiors painted (lac paintings) and with a hearth. Defensive forts were part of the settlements. Chalcolithic stone amulets with geometric shapes, pottery traditions with two-tiered furnaces for firing ceramics, terracotta figurines, stamp seals of clay and stone, and centres of metallurgical production were uncovered. Rosette and zoomorphic patterns were unearthed, representing various periods, both at Namazga-Tepe and also at other settlements in the foothills of the Kopetdag mountains. These are clearly indicative of the village cultures of Central Asia. | 1 | Applied and Interdisciplinary Chemistry |
In spectroscopy, the term "plane parallel layers" may be employed as a mathematical construct in discussing theory. The layers are considered to be semi-infinite. (In mathematics, semi-infinite objects are objects which are infinite or unbounded in some, but not all, possible ways.) Generally, a semi-infinite layer is envisioned as a being bounded by two flat parallel planes, each extending indefinitely, and normal (perpendicular) to the direction of a collimated (or directed) incident beam. The planes are not necessarily physical surfaces which refract and reflect light, but may just describe a mathematical plane, suspended in space. When the plane parallel layers have surfaces, they have been variously called plates, sheets, or slabs. | 0 | Theoretical and Fundamental Chemistry |
Extended aeration is typically used in prefabricated "package plants" intended to minimize design costs for waste disposal from small communities, tourist facilities, or schools. In comparison to traditional activated sludge, longer mixing time with aged sludge offers a stable biological ecosystem better adapted for effectively treating waste load fluctuations from variable occupancy situations. Supplemental feeding with something like sugar is sometimes used to sustain sludge microbial populations during periods of low occupancy; but population response to variable food characteristics is unpredictable, and supplemental feeding increases waste sludge volumes. Sludge may be periodically removed by septic tank pumping trucks as sludge volume approaches storage capacity. | 1 | Applied and Interdisciplinary Chemistry |
Many natural (or biological) materials are complex composites with remarkable mechanical properties. These complex structures, which have risen from hundreds of million years of evolution, are inspiring materials scientists in the design of novel materials. Their defining characteristics include structural hierarchy, multifunctionality and self-healing capability. Self-organization is also a fundamental feature of many biological materials and the manner by which the structures are assembled from the molecular level up. Thus, self-assembly is emerging as a new strategy in the chemical synthesis of high performance biomaterials. | 0 | Theoretical and Fundamental Chemistry |
A foam is said to be regular when the structure is ordered. Direct molding is one technology that produces regular foams with open pores. Metal foams can also be produced by additive processes such as selective laser melting (SLM).
Plates can be used as casting cores. The shape is customized for each application. This manufacturing method allows for "perfect" foam, so-called because it satisfies Plateau's laws and has conducting pores of the shape of a truncated octahedron Kelvin cell (body-centered cubic structure). | 0 | Theoretical and Fundamental Chemistry |
Fuzzy complexes are protein complexes, where structural ambiguity or multiplicity exists and is required for biological function. Alteration, truncation or removal of conformationally ambiguous regions impacts the activity of the corresponding complex. Fuzzy complexes are generally formed by intrinsically disordered proteins. Structural multiplicity usually underlies functional multiplicity of protein complexes following a fuzzy logic. Distinct binding modes of the nucleosome are also regarded as a special case of fuzziness. | 0 | Theoretical and Fundamental Chemistry |
In 2005 there were "several types of commercial cyclic olefin copolymers based on different types of cyclic monomers and polymerization methods. Cyclic olefin copolymers are produced by chain copolymerization of cyclic monomers such as 8,9,10-trinorborn-2-ene (norbornene) or 1,2,3,4,4a,5,8,8a-octahydro-1,4:5,8-dimethanonaphthalene (tetracyclododecene) with ethene (such as Polyplastics subsidiary TOPAS Advanced Polymers TOPAS, Mitsui Chemicals APEL), or by ring-opening metathesis polymerization of various cyclic monomers followed by hydrogenation (Japan Synthetic Rubbers ARTON, Zeon Chemicals Zeonex and Zeonor)." These later materials using a single type of monomer are more properly named cyclic olefin polymers (COP). | 0 | Theoretical and Fundamental Chemistry |
Circular RNA (CircRNA) are a novel class of endogenous noncoding RNAs and are characterized by their covalently closed loop structures. This class of ncRNA does not have a 5’ cap or 3’ Poly A tail. It has been hypothesized that cirRNAs may function as potential molecular markers for disease diagnosis and treatment and play an important role in the initiation and progression of human diseases. | 1 | Applied and Interdisciplinary Chemistry |
In the last step of duplex sequencing library preparation, Illumina sequencing adapters are added to the tagged double stranded libraries by PCR amplification using primers containing sequencing adapters. During PCR amplification, both complementary strands of DNA are amplified and generate two types of PCR products. Product 1 derives from strand 1's which have a unique tag sequence (called α in Figure 2) next to the Illumina adapter 1 and product 2 has a unique tag (called β in Figure 2) next to the Illumina adapter 1. (In each strand, tag α is the reverse complement of tag β and vice versa). The libraries containing duplex tags and Illumina adapters are sequenced using the Illumina TruSeq system. Reads that are originating from every single strand of DNA form a group of reads (tag families) that share the same tag. The detected families of reads will be used in the next step for analyzing sequencing data. | 1 | Applied and Interdisciplinary Chemistry |
The ruling in the Corby toxic waste case, delivered in July 2009, found Corby Borough Council liable in negligence, public nuisance and a breach of statutory duty for its reclamation of a steel works and the resulting atmospheric contamination. The case against the council cited: "The Defendants urban land reclamation programme and the presence of poisonous waste presented a significant risk to health. The poisonous waste was ultra hazardous and various sites contained substantial quantities of contaminated waste and toxic materials that were likely to cause personal injuries to persons in the surrounding area in the event of their escape." While recognising that there was insufficient epidemiological data to establish whether the victims injuries arose from a "common cause", or from airborne contamination or from the reclamation works, the judge ruled that there was a "statistically significant cluster" of birth defects in Corby which needed "explanation other than chance": it was not the courts purpose to establish whether the victims were individually exposed to contaminants from the reclamation, rather to determine whether any relevant breach of duty had the ability to cause injuries of the type complained of. The judge also ruled that it was "reasonably foreseeable that the local population might be exposed to hazardous or contaminated substances" as a result of the councils clean-up programme.
Matt Townsend, head of the environmental practice at Allen & Overy, says: "One of the important lessons from the case is that because of the rapidly evolving nature of environmental science and advancing knowledge and techniques, it will no longer be possible for developers to hide behind the science. To claim that you didn’t know is now unacceptable.". Stephen Matthew, a partner in the project group at corporate law firm Nabarro, advises: "Councils and regeneration bodies still need to be very open and clear about how they intend to deal with material on brownfield sites. Councils need to take professional advice... Don't leave a gaping hole for any future class actions."
Following the Corby ruling, Jason Addy stated: "The Corby ruling could have huge implications for the actions and responsibilities of Rochdale Council for the Spodden Valley site. Environmental pollution has been a problem at the Rochdale factory with acknowledged cases of asbestos-related cancer caused by environmental exposure." Laurie Kazan Allen, Editor of the British Asbestos Newsletter, said: "This landmark decision has ramifications for Rochdale Council regarding the Spodden Valley asbestos factory site. There is now a clear legal principle that local authorities hold a duty of care to protect communities from the hazardous effects of disturbing contaminated land. Since at least the 1960s there has been clear evidence that the inhalation of asbestos fibres, even in low quantities, can cause terminal cancer decades after initial exposure. Rochdale Council must take heed of this historic decision and act to protect local people."
Hilda Palmer of the Greater Manchester Hazards Centre said: "This has serious implications for Rochdale MBC in its management and control of the ex T&N site. The site is known to be extensively contaminated with the known carcinogen asbestos, which may be released into the air whenever the site is disturbed, and the invisible microscopic fibres spread in the air across the area to be inhaled by people, including children who are especially at risk of developing asbestos related terminal cancers such as mesothelioma years later. These facts are not in dispute and though the owner of the site is the responsible duty holder, the court judgment on Corby Council confirms the duty of care of a council as the planning authority and environmental health authority in terms of managing and controlling the risks to long term health presented by the airborne asbestos fibres from this site." | 1 | Applied and Interdisciplinary Chemistry |
Another potential devastating effect of nuclear war is termed nuclear winter. The idea become popularized in mainstream culture during the 1980s, when Richard P. Turco, Owen Toon, Thomas P. Ackerman, James B. Pollack and Carl Sagan collaborated and produced a scientific study which suggested the Earths weather and climate can be severely impacted by nuclear war. The main idea is that once a conflict begins and the aggressors start detonating nuclear weapons, the explosions will eject small particles from the Earths surface into the atmosphere as well as nuclear particles. Its also assumed that fires will break out and become widespread, similar to what happened at Hiroshima and Nagasaki during the end of WWII, which will cause soot and other harmful particles to also be introduced into the atmosphere. Once these harmful particles are lofted, strong upper-level winds in the troposphere can transport them thousands of kilometers and can end up transporting nuclear fallout and also alter the Earths radiation budget. Once enough small particles are in the atmosphere, they can act as cloud condensation nuclei which will cause global cloud coverage to increase which in turn blocks incoming solar insolation and starts a global cooling period. This is not unlike one of the leading theories about the extinction of most dinosaur species, in that a large explosion ejected small particulate matter into the atmosphere and resulted in a global catastrophe characterized by cooler temperatures, acid rain, and the KT Layer. | 0 | Theoretical and Fundamental Chemistry |
Many drugs which are substrates for glucuronidation as part of their metabolism are significantly affected by inhibitors or inducers of their specific glucuronisyltransferase types: | 0 | Theoretical and Fundamental Chemistry |
When compounds contain more than one functional group, the order of precedence determines which groups are named with prefix or suffix forms. The table below shows common groups in decreasing order of precedence. The highest-precedence group takes the suffix, with all others taking the prefix form. However, double and triple bonds only take suffix form (-en and -yn) and are used with other suffixes.
Prefixed substituents are ordered alphabetically (excluding any modifiers such as di-, tri-, etc.), e.g. chlorofluoromethane, not fluorochloromethane. If there are multiple functional groups of the same type, either prefixed or suffixed, the position numbers are ordered numerically (thus ethane-1,2-diol, not ethane-2,1-diol.) The N position indicator for amines and amides comes before "1", e.g., is N,2-dimethylpropanamine.
The order of remaining functional groups is only needed for substituted benzene and hence is not mentioned here. | 0 | Theoretical and Fundamental Chemistry |
Subsets and Splits