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Gene expression is regulated by histone acetylation and deacetylation, and this regulation is also applicable to inflammatory genes. Inflammatory lung diseases are characterized by expression of specific inflammatory genes such as NF-κB and AP-1 transcription factor. Treatments with corticosteroids and theophylline for inflammatory lung diseases interfere with HAT/HDAC activity to turn off inflammatory genes.
Specifically, gene expression data demonstrated increased activity of HAT and decreased level of HDAC activity in patients with Asthma. Patients with chronic obstructive pulmonary disease showed there is an overall decrease in HDAC activity with unchanged levels of HAT activity. Results have shown that there is an important role for HAT/HDAC activity balance in inflammatory lung diseases and provided insights on possible therapeutic targets. | 0 | Theoretical and Fundamental Chemistry |
CKLF like MARVEL transmembrane domain-containing 8 (i.e. CMTM8), previously termed chemokine-like factor superfamily 8 (i.e. CKLFSF8) has at least two isoforms, the CMTM8 and CMTM8-v2 proteins. Protein isoforms are variant products that are made by the alternative splicing of a single gene. The gene for these isoforms, CMTM8 (formerly termed CKLFSF8), is located in band 22 on the short (i.e. "p") arm of chromosome 3. The CMTM8 gene and its CMTM8 and CMTM8-v2 proteins belong to the CKLF-like MARVEL transmembrane domain-containing family of structurally and functionally related genes and proteins. The CMTM8 protein is the full-length and predominant product of the CMTM8 gene. This protein is expressed in a wide range of normal adult and fetal tissues while relatively little is known about the CMTM8-v2 protein. Studies suggest that the CMTM8 protein may be involved in the development of various cancers.
The levels of CMTM8 protein are lower in the tissues of non-small-cell lung carcinoma, colon cancer, rectal cancer, esophageal cancer, bladder cancer, stomach cancer, and glioblastoma brain tumors than in their respective adjacent normal organ tissues. The low levels of CMTM8 protein in bladder and stomach cancer tissues were associated with more aggressive diseases (e.g. presence of metastases) and poorer prognoses. These findings suggest that CMTM8 protein may inhibit the development and/or progression of the cited malignancies and therefore the CMTM8 gene functions as a tumor suppressor gene. However, further studies are required to support these conclusions and to determine if the levels of CMTM8 protein can be used as prognostic markers for these malignancies and/or as a targets for treating them. | 1 | Applied and Interdisciplinary Chemistry |
Fowler's scientific excellence and achievements have been recognized by prestigious awards, including the National Medal of Science, awarded in 2009 by President Obama. In 2003, Fowler was elected to the National Academy of Sciences.
Her numerous other honors include:
* 1997 – Society of Nuclear Medicine's Paul C. Aebersold Award for outstanding achievement in basic science
* 1998 – American Chemical Society's Francis P. Garvan-John M. Olin Medal
* 1998 – E.O. Lawrence Award, awarded by the Department of Energy
* 2000 – Society of Nuclear Imaging in Drug Development's Alfred P. Wolf Award
* 2002 – American Chemical Society's Glen T. Seaborg Award for Nuclear Chemistry
* 2005 – Distinguished Basic Scientist of the Year Award from the Academy of Molecular Imaging (AMI)
* 2008 – National Medal of Science, administered by the National Science Foundation and bestowed by the president of the United States
* 2009 – National Academy of Science Award in Chemical Sciences, awarded by the National Academy of Sciences
* 2011 – Distinguished Women in Chemistry/Chemical Engineering Award, sponsored by the American Chemical Society
* Distinguished Scientist Fellowship, sponsored by the Department of Energy's Office of Biological and Environmental Research | 0 | Theoretical and Fundamental Chemistry |
Operating positions for 2-port valves can be either shut (closed) so that no flow at all goes through, fully open for maximum flow, or sometimes partially open to any degree in between. Many valves are not designed to precisely control intermediate degree of flow; such valves are considered to be either open or shut. Some valves are specially designed to regulate varying amounts of flow. Such valves have been called by various names such as regulating, throttling, metering, or needle valves. For example, needle valves have elongated conically-tapered discs and matching seats for fine flow control. For some valves, there may be a mechanism to indicate by how much the valve is open, but in many cases other indications of flow rate are used, such as separate flow meters.
In plants with remote-controlled process operation, such as oil refineries and petrochemical plants, some 2-way valves can be designated as normally closed (NC) or normally open (NO) during regular operation. Examples of normally-closed valves are sampling valves, which are only opened while a sample is taken. Other examples of normally-closed valves are emergency shutdown valves, which are kept open when the system is in operation and will automatically shut by taking away the power supply. This happens when there is a problem with a unit or a section of a fluid system such as a leak in order to isolate the problem from the rest of the system. Examples of normally-open valves are purge-gas supply valves or emergency-relief valves. When there is a problem these valves open (by switching them off) causing the unit to be flushed and emptied.
Although many 2-way valves are made in which the flow can go in either direction between the two ports, when a valve is placed into a certain application, flow is often expected to go from one certain port on the upstream side of the valve, to the other port on the downstream side. Pressure regulators are variations of valves in which flow is controlled to produce a certain downstream pressure, if possible. They are often used to control flow of gas from a gas cylinder. A back-pressure regulator is a variation of a valve in which flow is controlled to maintain a certain upstream pressure, if possible. | 1 | Applied and Interdisciplinary Chemistry |
Changes in these quantities are useful for assessing the degree to which a chemical reaction will proceed. The relevant quantity depends on the reaction conditions, as shown in the following table. denotes the change in the potential and at equilibrium the change will be zero.
Most commonly one considers reactions at constant and , so the Gibbs free energy is the most useful potential in studies of chemical reactions. | 0 | Theoretical and Fundamental Chemistry |
Unlike hydrodynamic developed flow, a constant profile shape is used to define thermally fully developed flow because temperature continually approaches ambient temperature. Dimensionless analysis of change in profile shape defines when a flow is thermally fully developed.
Requirement for thermally fully developed flow:
Thermally developed flow results in reduced heat transfer compared to developing flow because the difference between the surface temperature of the pipe and the mean temperature of the flow is greater than the temperature difference between surface temperature of the pipe and the temperature of the fluid near the pipe boundary. | 1 | Applied and Interdisciplinary Chemistry |
There are many ways to install screen media into a screen box deck (shaker deck). Also, the type of attachment system has an influence on the dimensions of the media. | 1 | Applied and Interdisciplinary Chemistry |
He was born in Tel Aviv, Israel and sent to an English boarding school at the age of 7. After completing his secondary education he returned to Israel to carry out his military service before moving back to England to study the Natural Sciences Tripos at the University of Cambridge. He received his Ph.D. in Physics from Christ's College, Cambridge in 1972 under the supervision of David Tabor. He then became a Research Fellow at the Biophysics Institute, University of Stockholm and at the Karolinska Institute, Sweden until 1974.
He moved to Australia to take a post as fellow in the Research School of Physical Science and the Research School of Biological Sciences at the Institute of Advanced Studies, Australian National University in Canberra from 1974 to 1977. He was then appointed senior fellow in the Department of Applied Mathematics and Department of Neurobiology at the Institute of Advanced Studies, Australian National University in Canberra.
He relocated to California to join UCSB in 1986, where he worked till his death on the 20th of September 2018. | 0 | Theoretical and Fundamental Chemistry |
Things can be somewhat improved by using two accelerators firing at each other instead of a single accelerator and a non-moving target. In this case, the second fuel, boron in the example above, is already ionized, so the "ionization drag" seen by the protons entering the solid block is eliminated.
In this case, however, the concept of a characteristic interaction length has no meaning as there is no solid target. Instead, for these types of system, the typical measure is to use the beam luminosity, L, a term that combines the reaction cross-section with the number of events. The term is normally defined as:
For this discussion, we will re-arrange it to extract the collisional frequency:
Each of these collisions will produce 8.7 MeV, so multiplying by gives the power. To generate N collisions one requires luminosity L, generating L requires power, so one can calculate the amount of power needed to produce a given L through:
If we set P to 1 MW, equivalent to a small wind turbine, this requires an L of 10 cms. For comparison, the world record for luminosity set by the Large Hadron Collider in 2017 was 2.06 x 10 cms, more than seven orders of magnitude too low. | 0 | Theoretical and Fundamental Chemistry |
Electropolishing, also known as electrochemical polishing, anodic polishing, or electrolytic polishing (especially in the metallography field), is an electrochemical process that removes material from a metallic workpiece, reducing the surface roughness by levelling micro-peaks and valleys, improving the surface finish. Electropolishing is often compared to, but distinctly different from, electrochemical machining. It is used to polish, passivate, and deburr metal parts. It is often described as the reverse of electroplating. It may be used in lieu of abrasive fine polishing in microstructural preparation. | 1 | Applied and Interdisciplinary Chemistry |
DNA supercoiling refers to the amount of twist in a particular DNA strand, which determines the amount of strain on it. A given strand may be "positively supercoiled" or "negatively supercoiled" (more or less tightly wound). The amount of a strand's supercoiling affects a number of biological processes, such as compacting DNA and regulating access to the genetic code (which strongly affects DNA metabolism and possibly gene expression). Certain enzymes, such as topoisomerases, change the amount of DNA supercoiling to facilitate functions such as DNA replication and transcription. The amount of supercoiling in a given strand is described by a mathematical formula that compares it to a reference state known as "relaxed B-form" DNA. | 1 | Applied and Interdisciplinary Chemistry |
The receptor-based approach is used in exposure science. It starts by looking at different contaminants and concentrations that reach people. An exposure analyst can use direct or indirect measurements to determine if a person has been in contact with a specific contaminant or has been exposed to a specific risk (e.g. accident). Once a contaminant has been proved to reach people, exposure analysts work backwards to determine its source. After the identification of the source, it is important to find out the most efficient way to reduce adverse health effects. If the contaminant reaches a person, it is very hard to reduce the associated adverse effects. Therefore, it is very important to reduce exposure in order to diminish the risk of adverse health effects. It is highly important to use both regulatory and non-regulatory approaches in order to decrease peoples exposure to contaminants. In many cases, it is better to change peoples activities in order to reduce their exposures rather than regulating a source of contaminants.
The receptor-based approach can be opposed to the source-based approach. This approach begins by looking at different sources of contaminants such as industries and power plants. Then, it is important to find out if the contaminant of interest has reached a receptor (usually humans). With this approach, it is very hard to prove that a pollutant from a source has reached a target. | 1 | Applied and Interdisciplinary Chemistry |
Triphenylphosphine dichloride, (CH)PCl, is a chlorinating agent widely used in organic chemistry. Applications include the conversion of alcohols and ethers to alkyl chlorides, the cleavage of epoxides to vicinal dichlorides and the chlorination of carboxylic acids to acyl chlorides. | 0 | Theoretical and Fundamental Chemistry |
Molecular photoswitches are utilized in the field of photopharmacology, where the energetics of a molecule can be reversibly controlled with light to achieve spatial and temporal resolution of a particular effect. Photoswitches may function by undergoing photoisomerization through which light is used to conformationally adapt a molecule to a biological site, or through an environmental effect where an external factor such as a solvent effect or hydrogen bonding can selectively allow or quench an emissive state within a molecule. To visualize photophysical processes, a useful depiction is the Jablonski diagram. This is a diagram which depicts electronic and vibrational energy levels within a molecule as vertical levels and shows the possible relaxation pathways from excited states. Typically, the ground state is referred to as S, and is drawn at the bottom of the figure with nearby vibrational excitations just above it. An absorption will promote an electron into the S state at any vibrational energy level, or into a higher order excited state if the absorbed energy has enough magnitude. The excited state can then undergo internal conversion which is the electronic relaxation to a lower state with the same vibrational energetics or vibrational relaxation within a state. This may be followed by an intersystem crossing wherein the electron undergoes a spin flip, or a radiative or nonradiative decay back to the ground state.
One example of an organic compound that undergoes photoisomerization is azobenzene. The structure is two phenyl rings joined with a N=N double bond and is the simplest aryl azo compound. Azobenzene and its derivatives have two accessible absorbance bands: the S state from a n-π* transition which can be excited into using blue light, and the S state from a π-π* transition that can be excited into using ultraviolet light. Azobenzene and its derivatives have two isomers, trans and cis. The trans isomer, having the phenyl rings on opposite sides of the azo double bond, is the thermally preferred isomer as there is less stereoelectronic distortion and more delocalization present. However, excitation of the trans isomer to the S state facilitates a shift to the cis isomer. The S absorption is associated with a conversion back to the trans isomer. In this way, azobenzene and its derivatives can act as reversible stores of energy by maintaining a strained configuration in the cis isomer. Modifications of the substituents on azobenzene allow the energetics of these absorptions to be tuned, and if they are engineered such that the two absorption bands overlap a single wavelength of light can be used to flip between them. There are a number of similar photoswitches which isomerize between E and Z configurations across an azo group (for instance, azobenzene and azopyrazole) or an ethylene bridge (for instance, stilbene and hemithioindigo).
Alternatively, photoswitches may themselves be emissive and exhibit environmental control over their properties. One such example is a class of ruthenium polypyridyl coordination complexes. Typically they contain two bidentate bipyridine or phenanthroline ligands and an extended phenanthroline-phenazine bidentate ligand such as dipyrido[3,2-a:2,3-c]phenazine (dppz).These complexes have an accessible metal to ligand charge transfer excited state (MLCT) which undergoes rapid intersystem crossing to a MLCT state due to the strong spin-orbit coupling of the ruthenium center. These excited states are localized on the extended ligand phenazine nitrogens, and emission occurs from the MLCT state. Hydrogen bonding interactions such as the presence of water around these nitrogen atoms stabilizes the MLCT state, quenching the emission process. Thus, by controlling whether an aqueous or otherwise protic polar solvent is present, emissive behaviors can be “turned on/off”, and alternation between “bright states” and “dark states” is facilitated. This light switch behavior makes these and similar complexes of recent interest in photopharmacological applications such as photodynamic therapy. | 1 | Applied and Interdisciplinary Chemistry |
Steatocrit or acid steatocrit is a simple, rapid gravimetric method to determine steatorrhea. The test is simple, rapid, inexpensive, and reliable. It is a qualitative test that can be used when other methods are impractical.
__TOC__ | 1 | Applied and Interdisciplinary Chemistry |
There are number of methods available to complete a runoff footprint. The simplest methods involve using a runoff coefficient, which according to the State Water Resources Control Board of California is "a dimensionless coefficient relating the amount of runoff to the amount of precipitation received. It is a larger value for areas with low infiltration and high runoff (pavement, steep gradient), and lower for permeable, well vegetated areas (forest, flat land)." The runoff coefficients for different surface types on a site can be multiplied with the area for each surface along with the annual precipitation to generate a rough runoff footprint. If the runoff coefficient and areas of proposed stormwater green solutions like rain gardens and bioswales for the site are known, the reduction in overall runoff from these improvements can be estimated.
More accurate runoff footprint tools exist. By using computer modeling and detailed weather data, complex runoff footprints can be made easy. The amounts of pollution in the stormwater runoff can be estimated, and the effects of combinations of stormwater green solutions can be assessed. The James River Association of central Virginia provides an [http://www.jamesriverassociation.org/get-involved/runoff-calculator/ online tool] where property owners in the James River watershed can generate a site-specific runoff pollution report. MyRunoff.org provides an online [http://www.myrunoff.org runoff footprint calculator] for property owners across the United States to estimate their baseline runoff and the reduction from different scenarios of rain barrels and rain gardens. The EPA launched the National Stormwater Calculator in July, 2013, which is a desktop application for Windows allowing users to model the annual impact of a range of stormwater green solutions. | 1 | Applied and Interdisciplinary Chemistry |
Model systems consisting of a single phospholipid or a mixture have been studied by physical chemists. Cardiolipin is found mainly in mitochondrial membranes, and calcium ions play an important role in the respiratory processes mediated by the mitochondrion. The forces involved have been postulated to explain this process in terms of nucleation for agglomeration of smaller supramolecular entities or phase changes in the structure of the biomembranes. | 1 | Applied and Interdisciplinary Chemistry |
The heat death paradox, also known as thermodynamic paradox, Clausius paradox, and Kelvins paradox, is a reductio ad absurdum argument that uses thermodynamics to show the impossibility of an infinitely old universe. It was formulated in February 1862 by Lord Kelvin and expanded upon by Hermann von Helmholtz and William John Macquorn Rankine. | 0 | Theoretical and Fundamental Chemistry |
A subcategory of nucleophilic/electrophilic sequences is constituted by organocatalytic
cascades, in which the key nucleophilic attack is driven by organocatalysis.
An organocatalytic cascade was employed in the total synthesis of the natural product harziphilone, reported by Sorensen et al. in 2004 (Scheme 3). Herein, treatment of the enone starting material 13 with organocatalyst 14 yielded intermediate 15 via conjugate addition. Subsequent cyclization by the intramolecular Michael addition of the enolate into the triple bond of the system gave species 16, which afforded intermediate 17 after proton transfer and tautomerization. The cascade was completed by elimination of the organocatalyst and a spontaneous 6π-electrocyclic ring closure of the resultant cis-dienone 18 to (+)-harziphilone (19) in 70% overall yield.
An outstanding triple organocatalytic cascade was reported by Raabe et
al. in 2006. Linear aldehydes (20),
nitroalkenes (21) and α,β-unsaturated
aldehydes (22) could be condensed
together organocatalytically to afford tetra-substituted
cyclohexane carbaldehydes (24) with
moderate to excellent diastereoselectivity and complete enantiocontrol (Scheme
4). The transformation is mediated by the readily
available proline-derived organocatalyst 23.
The transformation was proposed to
proceed via a Michael addition/Michael addition/aldol condensation sequence
(Scheme 5). In the first step, Michael addition of
aldehyde 20 to nitroalkene 21 occurs through enamine catalysis,
yielding nitroalkane 25. Condensation
of α,β-unsaturated aldehyde 22 with the organocatalyst then
facilitates the conjugate addition of 25
to give intermediate enamine 26,
which is prone to undergo an intramolecular aldol condensation to iminium
species 27. Organocatalyst 23 is regenerated by hydrolysis, along
with the product 24, thus closing
the triple cascade cycle. | 0 | Theoretical and Fundamental Chemistry |
The Mark III design encompassed the greatest improvement in the technology since its commercialisation. The focus was to make the technology more robust and easier to use in operations. The total redesign of the downcomer assembly allowed it to be isolated and unblocked much more easily compared to the Mark II design. The Mark III design also saw slurry flow per downcomer to be increased from 60 m/h to 75–85 m/h using larger orifice sizes in the slurry lenses.
The Mark III Cell was introduced in 2000. It included the following improvements:
* a new slurry lens orifice design (see Figures 7 and 8)
* a new design downcomer and nozzle
* a new design flat plate bubble dispersers
* a stainless steel adjustable above and in-froth wash water system (see Figure 9)
* automated air and wash water flow control
* air-isolating slurry-eliminating valves ("AISE valves")
* a bottom-fed new slurry distributor.
The earlier models of the Jameson Cell used orifice plates to generate the downcomer jet. The new slurry lens design had a smooth, shallow entry angle that created an optimum flow regime over the ceramic, reducing wear and extending its life. The shape resulted in a decrease in power consumption by the feed slurry pump by up to 10% and resulted in better jet formation that improved air entrainment.
For coal applications, the wash water addition system was changed from a tray to stainless-steel circular rings attached to a manual lifting system. This allowed the flexibility of an easy transition from above-froth wash water addition to the in-froth addition that might be necessary for high concentrate-grade operations. For metals applications, new design wash water trays consisting of removable rubber mats for easy maintenance were used.
The AISE valves were developed to prevent solids being sucked back into the air lines when individual downcomers become blocked. Solids depositing in the air lines and their build up in the air distributor decreases flotation performance as it prevents air from being efficiently entrained in the downcomers. | 1 | Applied and Interdisciplinary Chemistry |
Mach tuck is an aerodynamic effect whereby the nose of an aircraft tends to pitch downward as the airflow around the wing reaches supersonic speeds. This diving tendency is also known as tuck under. The aircraft will first experience this effect at significantly below Mach 1. | 1 | Applied and Interdisciplinary Chemistry |
Hua-Zhong "Hogan" Yu (于化忠) is presently a professor of materials and analytical chemistry at Simon Fraser University in metro Vancouver, Canada, where he leads a research laboratory working on Surfaces and Materials for Sensing. He is also an associate editor for Analyst, the journal for Analytical and Bioanalytical Sciences from the Royal Society of Chemistry in UK, and an adjunct professor in the College of Biomedical Engineering, Taiyuan University of Technology in Shanxi, China. | 0 | Theoretical and Fundamental Chemistry |
where is specific enthalpy, is dissipation function and is temperature. And where
i.e. internal energy per unit volume equals mass density times the sum of: proper energy per unit mass, kinetic energy per unit mass, and gravitational potential energy per unit mass.
i.e. change in heat per unit volume (negative divergence of heat flow) equals the divergence of heat conductivity times the gradient of the temperature.
i.e. divergence of work done against stress equals flow of material times divergence of stress plus stress times divergence of material flow.
i.e. stress times divergence of material flow equals deviatoric stress tensor times divergence of material flow minus pressure times material flow.
i.e. enthalpy per unit mass equals proper energy per unit mass plus pressure times volume per unit mass (reciprocal of mass density). | 0 | Theoretical and Fundamental Chemistry |
In the case of sulfides and carbonates, a process called "roasting" removes the unwanted carbon or sulfur, leaving an oxide, which can be directly reduced. Roasting is usually carried out in an oxidizing environment. A few practical examples:
* Malachite, a common ore of copper is primarily copper carbonate hydroxide Cu(CO)(OH). This mineral undergoes thermal decomposition to 2CuO, CO, and HO in several stages between 250 °C and 350 °C. The carbon dioxide and water are expelled into the atmosphere, leaving copper(II) oxide, which can be directly reduced to copper as described in the following section titled Reduction.
* Galena, the most common mineral of lead, is primarily lead sulfide (PbS). The sulfide is oxidized to a sulfite (PbSO), which thermally decomposes into lead oxide and sulfur dioxide gas (PbO and SO). The sulfur dioxide is expelled (like the carbon dioxide in the previous example), and the lead oxide is reduced as below. | 1 | Applied and Interdisciplinary Chemistry |
Ketenimines are a group of organic compounds sharing a common functional group with the general structure RRC=C=NR. A ketenimine is a cumulated alkene and imine and is related to an allene and a ketene.
The parent compound is ketenimine or CHCNH. The most recent work by Bane et al. investigates the rovibrational structure of the ν and ν bands in the high-resolution FTIR spectrum, complementing the earlier analysis of the pure rotational spectrum. This pair of Coriolis coupled bands provide a rare example where intensity sharing between bands yields sufficient intensity for an otherwise invisible band (ν). | 0 | Theoretical and Fundamental Chemistry |
Compared with other parts of the United States, the number of vegetated roofs currently in the Southeast is significantly less. Vegetated roofs in humid subtropical regions rely on the same core green roof terminologies that are used throughout the world and other parts of the United States. Extensive, intensive, soil media, ballast, filter fabric, drainage layer, waterproof membrane are some of the core green roof component terms associated with SCV roofs.
Regional terms, plant palettes, and technologies are forming to adapt to recent innovations and increased popularity of green roofs in the humid, subtropical regions of the United States. All forms of green roofs have the potential to retain stormwater on the roof surface and lower the thermal loading on buildings. Due to high temperatures, prolonged heat, and excessive amounts of precipitation, humid subtropical regions of the United States receive the greatest environmental benefits provided by SCV roofs, which are: reduced rainwater input into storm water retention systems during rainfall and increased energy performance ratings in buildings. SCV and green roofs increase energy efficiencies of buildings by stabilizing roof surface temperatures. In other regions of the United States, the greatest environmental benefits of green roof design may be different based upon the type of climate the area possesses.
Recent advancements in soil engineering and plastic technologies allow vegetated roofs the ability to adapt to different locations within the humid, subtropical region of the United States. Soil media moisture content and capacity levels can be regulated by using soil elements that adapt to the climate of each specific geographic location and client needs. The amount of moisture retained depends on the maximum moisture retention capacity, the permeability and the depth of the soil media. High density plastics permit SCV roof systems to withstand the weather elements and adjust to varying building types of the region.
As defined by green roof industry standards, extensive green roofs have a soil media of less than 6 inches in depth and intensive green roofs have a soil media of more than 6 inches in depth. Most SCV roofs that are greater than 6 inches in depth are expensive and found on residential high rise structures, often containing pools and other amenities.
An SCV roofs requires a unique soil media mixture to adapt to the harsh weather conditions and physical characteristics of the southern United States. Expanded shall and clay are typically used to form a base and comprise up to 90% of some soil media mixtures used throughout the United States. Perlite, vermiculite, ash, tire crumbs, sand, peat moss, and recycled vegetation are some of the other elements utilized in soil media engineering. Albedo and heat transfer rates are key variables to consider when designing an SCV roof and do not have a significant effect on green roofs in the northern continental United States.
There are three basic SCV and green roof systems available in today's market: built-up, modular, and mat. These systems vary from manufacture to manufacture and are composed of different materials such as: foam, high density plastic, and fabrics. Many of the systems have geographic limitations and do not perform well in humid, subtropical regions based upon the intent of the system and the materials being used. | 1 | Applied and Interdisciplinary Chemistry |
CDC Director Mandy Cohen serves concurrently/ex officio as ATSDR administrator and CDC director, heading the Office of the Administrator. Patrick N. Breysse, PhD. serves as director of NCEH/ATSDR, heading the Office of the Director. The ATSDR administrator/CDC director, who provides overall leadership of the agency, is appointed by the president of the United States; the appointment does not require Senate approval. The ATSDR administrator appoints the NCEH/ATSDR director, who is responsible for managing the agency's programs and activities. | 1 | Applied and Interdisciplinary Chemistry |
* Frq – The Frq gene, also known as the Frequency gene, encodes central components of an oscillatory loop within the circadian clock in Neurospora. In the oscillator's feedback loop, frq gives rise to transcripts that encode for two forms of the FRQ protein. Both forms are required for robust rhythmicity throughout the organism. Rhythmic changes in the amount of frq transcript are essential for synchronous activity, and abrupt changes in frq levels reset the clock. | 1 | Applied and Interdisciplinary Chemistry |
The amount of material available for assimilating into organismal cells controls the rate of metabolism at the cellular to lake ecosystem level. In lakes, phosphorus and nitrogen are the most common limiting nutrients of primary production and ecosystem respiration. Foundational work on the positive relationship between phosphorus concentration and lake eutrophication resulted in legislation that limited the amount of phosphorus in laundry detergents, among other regulations. Although phosphorus is often used as a predictor of lake ecosystem productivity and excess phosphorus as an indicator of eutrophication, many studies show that metabolism is co-limited by phosphorus and nitrogen or nitrogen alone. The balance between phosphorus, nitrogen, and other nutrients, termed ecological stoichiometry, can dictate rates of organismal growth and whole-lake metabolism through cellular requirements of these essential nutrients mediated by life-history traits. For example, fast-growing cladocerans have a much lower nitrogen to phosphorus ratio (N:P) than copepods, mostly due to the high amount of phosphorus-rich RNA in their cells used for rapid growth. Cladocerans residing in lakes with high N:P ratios relative to cladoceran body stoichiometry will be limited in growth and metabolism, having effects on whole-lake metabolism. Furthermore, cascading effects from food web manipulations can cause changes in productivity from changes to nutrient stoichiometry. For example, piscivore addition can reduce predation pressure on fast-growing, low N:P cladocerans which increase in population rapidly, retain phosphorus in their cells, and can cause a lake to become phosphorus limited, consequently reducing whole-lake primary productivity. | 1 | Applied and Interdisciplinary Chemistry |
Within the chemical universe, the fine chemical industry is positioned between the commodity, their suppliers, and specialty chemical industries, their customers. Depending on the services offered, there are two types of fine chemical companies. The Fine Chemical Companies are active in industrial scale production, both of standard and exclusive products. If the latter prevails, they are referred to as Fine Chemical / Custom Manufacturing Organizations (CMOs). The main assets of the Contract Research Organizations (CROs) are their research laboratories. CRAMS; Contract Research and Manufacturing Organizations are hybrids (see section 4.2). | 0 | Theoretical and Fundamental Chemistry |
Reproductive cloning generally uses "somatic cell nuclear transfer" (SCNT) to create animals that are genetically identical. This process entails the transfer of a nucleus from a donor adult cell (somatic cell) to an egg from which the nucleus has been removed, or to a cell from a blastocyst from which the nucleus has been removed. If the egg begins to divide normally it is transferred into the uterus of the surrogate mother. Such clones are not strictly identical since the somatic cells may contain mutations in their nuclear DNA. Additionally, the mitochondria in the cytoplasm also contains DNA and during SCNT this mitochondrial DNA is wholly from the cytoplasmic donor's egg, thus the mitochondrial genome is not the same as that of the nucleus donor cell from which it was produced. This may have important implications for cross-species nuclear transfer in which nuclear-mitochondrial incompatibilities may lead to death.
Artificial embryo splitting or embryo twinning, a technique that creates monozygotic twins from a single embryo, is not considered in the same fashion as other methods of cloning. During that procedure, a donor embryo is split in two distinct embryos, that can then be transferred via embryo transfer. It is optimally performed at the 6- to 8-cell stage, where it can be used as an expansion of IVF to increase the number of available embryos. If both embryos are successful, it gives rise to monozygotic (identical) twins. | 1 | Applied and Interdisciplinary Chemistry |
A related technique pumps deuterium gas through the wall of a palladium-silver alloy tubing. The palladium is electrolytically loaded with deuterium. In some experiments this produces fast neutrons that trigger further reactions. Other experimenters (Fralick et al.) also made claims of anomalous heat produced by this system. | 0 | Theoretical and Fundamental Chemistry |
The first heteropoly molybdate and first heteropolymetallate, yellow ammonium phosphomolybdate, (NH)PMoO was discovered by Berzelius in 1826. The phosphorus atom in the anion is termed the heteroatom, other heteroatoms are silicon and arsenic. The heteropoly-molybdenum blues have structures based on the Keggin structure. The blue colour arises because the near-colourless anion, such as the phosphomolybdate anion, , can accept more electrons (i.e. be reduced) to form an intensely coloured mixed-valence complex. This can occur in one electron or two electron steps. The reduction process is reversible and the structure of the anion is essentially unchanged.
: PMo + 4 e ⇌ PMoMo
The structure of the anion, PMoMo, has been determined in the solid state and is a β-isomer (i.e. with one of the four groups of edge-shared octahedra on the α-Keggin ion rotated through 60°). Similar structures have been found with silicon, germanium or arsenic heteroatoms.
The intense blue colour of the reduced anion is the basis for the use of heteropoly-molybdenum blues in quantitative and qualitative analytical techniques.
This property is exploited as follows:
*the sample to be analysed is reacted to produce the reduced blue heteropoly-molybdate in order to:
**detect the presence of a hetero atom in e.g. a spot test
** measure the amount of a hetero atom present in the sample colorimetrically
*the sample is added to a solution of the near colourless, unreduced complex in order to:
**detect the presence of a reducing compound e.g. a reducing sugar such as glucose
**measure the amount of a reducing compound in a two step procedure | 0 | Theoretical and Fundamental Chemistry |
In organic chemistry, the anomeric effect or Edward-Lemieux effect (after J. T. Edward and Raymond Lemieux) is a stereoelectronic effect that describes the tendency of heteroatomic substituents adjacent to a heteroatom within a cyclohexane ring to prefer the axial orientation instead of the less-hindered equatorial orientation that would be expected from steric considerations. This effect was originally observed in pyranose rings by J. T. Edward in 1955 when studying carbohydrate chemistry.
The term anomeric effect was introduced in 1958. The name comes from the term used to designate the lowest-numbered ring carbon of a pyranose, the anomeric carbon. Isomers that differ only in the configuration at the anomeric carbon are called anomers. The anomers of -glucopyranose are diastereomers, with the beta anomer having a hydroxyl () group pointing up equatorially, and the alpha anomer having that () group pointing down axially.
The anomeric effect can also be generalized to any cyclohexyl or linear system with the general formula , where Y is a heteroatom with one or more lone pairs, and X is an electronegative atom or group. The magnitude of the anomeric effect is estimated at about 4-8 kJ/mol in the case of sugars, but is different for every molecule.
In the above case, the methoxy group ) on the cyclohexane ring (top) prefers the equatorial position. However, in the tetrahydropyran ring (bottom), the methoxy group prefers the axial position. This is because in the cyclohexane ring, Y = carbon, which is not a heteroatom, so the anomeric effect is not observed and sterics dominates the observed substituent position. In the tetrahydropyran ring, Y = oxygen, which is a heteroatom, so the anomeric effect contributes and stabilizes the observed substituent position. In both cases, X = methoxy group.
The anomeric effect is most often observed when Y = oxygen, but can also be seen with other lone pair bearing heteroatoms in the ring, such as nitrogen, sulfur, and phosphorus.
The exact method by which the anomeric effect causes stabilization is a point of controversy, and several hypotheses have been proposed to explain it. | 0 | Theoretical and Fundamental Chemistry |
For most purposes, ozone production would be a detrimental side effect of lamp operation. To prevent this, most germicidal lamps are treated to absorb the 185 nm mercury emission line (which is the longest wavelength of mercury light which will ionize oxygen).
In some cases (such as water sanitization), ozone production is precisely the point. This requires specialized lamps which do not have the surface treatment. | 0 | Theoretical and Fundamental Chemistry |
In recent publications, prof. Sindo Kou has proposed an approach to evaluate susceptibility to solidification cracking; this approach is based on a similar approach where a quantity, , which has the dimensions of a temperature is proposed as an index of the cracking susceptibility. Again one could exploit Scheil based solidification curves to link this index to the slope of the (Scheil) solidification curve:
∂T/(∂(fS)^1/2)=
∂T/(∂(fS)*(∂(fS)^1/2)/∂(fS))=
(1/2)∂T/∂(fS)*(fS)^1/2= | 1 | Applied and Interdisciplinary Chemistry |
Pronounced intensity minima were first observed in 1930 by Theodor Estermann, Otto Frisch, and Otto Stern, during a series of gas-surface interaction experiments attempting to demonstrate the wave nature of atoms and molecules. The phenomenon has been explained in 1936 by John Lennard-Jones and Devonshire in terms of resonant transitions to bound surface states. | 0 | Theoretical and Fundamental Chemistry |
Solomon equations are used to calculate the transfer of magnetization as a result of relaxation in a dipolar system. They can be employed to explain the nuclear Overhauser effect, which is an important tool in determining molecular structure. | 0 | Theoretical and Fundamental Chemistry |
The structure consists of a peptide loop of seven amino acids (L-glutamic acid, L-leucine, D-leucine, L-valine, L-aspartic acid, D-leucine, and L-leucine) and a β-hydroxy fatty acid of variable length, thirteen to fifteen carbon atoms long. The glutamic acid and aspartic acid residues give the ring its hydrophilic character, as well as its negative charge. Conversely, the valine residue extends down, facing the fatty acid chain, to form a major hydrophobic domain. Below critical micellar concentrations (CMCs), the fatty acid tail can extend freely into solution, participating in hydrophobic interactions within micelles. This antibiotic is synthesized by a linear nonribosomal peptide synthetase, surfactin synthetase (). In solution, it has a characteristic "horse saddle" conformation (PDB: ) that explains its large spectrum of biological activity. | 0 | Theoretical and Fundamental Chemistry |
In 2020, the gas-diffusion electrocrystallization process was presented as a great EU-funded innovation by the Innovation Radar of the European Commission, for its application on the secondary recovery of platinum group metals. | 0 | Theoretical and Fundamental Chemistry |
Operation Groundhog was reported a joint US/Kazakh/Russian program to secure radioactive residues of Soviet-era nuclear bomb tests. In 2003, reports appeared in Science Magazine that the program included paving some areas with thick layers of reinforced concrete to protect plutonium contaminating the ground, in order to prevent terrorists from acquiring contaminated material for making a dirty bomb. | 0 | Theoretical and Fundamental Chemistry |
A melanotroph (or melanotrope) is a cell in the pituitary gland that generates melanocyte-stimulating hormone (α‐MSH) from its precursor pro-opiomelanocortin. Chronic stress can induce the secretion of α‐MSH in melanotrophs and lead to their subsequent degeneration. | 1 | Applied and Interdisciplinary Chemistry |
* Cultivating peatland products sustainably can incentivise the rewetting of drained peatlands, while maintaining similar land use in previously drained agricultural areas
* Raw materials can be grown on peatlands without competing with food production for land in other areas.
* The growing of crops extracts phosphate from the land, which is important in wetlands; it also helps to extract other nutrients from water, making it suitable for post-water treatment purposes
* In many tropical countries, cultivating semi-wild native crops in peat swamp forests is a traditional livelihood which can be sustainable.
* Restored reed beds can obstruct nitrogen and phosphorus run-off from agriculture higher up in the river system and so protect lower waters.
* Paludiculture areas can act as habitat corridors and ecological buffer zones between traditional agriculture and intact peatlands
abc | 1 | Applied and Interdisciplinary Chemistry |
Very few parts of the sympathetic system use cholinergic receptors. In sweat glands the receptors are of the muscarinic type. The sympathetic nervous system also has some preganglionic nerves terminating at the chromaffin cells in the adrenal medulla, which secrete epinephrine and norepinephrine into the bloodstream. Some believe that chromaffin cells are modified postganglionic CNS fibers. In the adrenal medulla, acetylcholine is used as a neurotransmitter, and the receptor is of the nicotinic type.
The somatic nervous system uses a nicotinic receptor to acetylcholine at the neuromuscular junction. | 1 | Applied and Interdisciplinary Chemistry |
Environmental radioactivity is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium-90 (Sr) and technetium-99 (Tc), are only found on Earth as a result of human activity, and some, like potassium-40 (K), are only present due to natural processes, a few isotopes, e.g. tritium (H), result from both natural processes and human activities. The concentration and location of some natural isotopes, particularly uranium-238 (U), can be affected by human activity. | 0 | Theoretical and Fundamental Chemistry |
Similarly to the resolving power of a diffraction grating, which is determined by the number of the illuminated grating elements and the order of diffraction, the resolving power of a VIPA is determined by the reflectivity of the back surface of the VIPA and the thickness of the glass plate. For a fixed thickness, a high reflectivity causes light to stay longer in the VIPA. This creates more virtual sources of light and thus increases the resolving power. On the other hand, with a lower reflectivity, the light in the VIPA is quickly lost, meaning fewer virtual sources of light are superimposed. This results in lower resolving power.
For large angular dispersion with high resolving power, the dimensions of the VIPA should be accurately controlled. Fine tuning of the VIPA characteristics was demonstrated by developing an elastomer-based structure (Metz, 2013).
A constant reflectivity of the partially transmissive mirror in the VIPA produces a Lorentzian power distribution when the output light is imaged onto a screen, which has a negative effect on the wavelength selectivity. This can be improved by providing the partially transmissive mirror with a linearly decreasing reflectivity. This leads to a Gaussian-like power distribution on a screen and improves the wavelength selectivity or the resolving power. | 0 | Theoretical and Fundamental Chemistry |
Flutamide has also been associated with interstitial pneumonitis (which can progress to pulmonary fibrosis). The incidence of interstitial pneumonitis with flutamide was found to be 0.04% (4 per 10,000) in a large clinical cohort of 41,700 prostate cancer patients. A variety of case reports have associated flutamide with photosensitivity. Flutamide has been associated with several case reports of methemoglobinemia. Bicalutamide does not appear to share this risk with flutamide. Flutamide has also been associated with reports of sulfhemoglobinemia and neutropenia. | 0 | Theoretical and Fundamental Chemistry |
The primary uses of esomeprazole are gastroesophageal reflux disease, treatment and maintenance of erosive esophagitis, treatment of duodenal ulcers caused by H. pylori, prevention of gastric ulcers in those on chronic NSAID therapy, and treatment of gastrointestinal ulcers associated with Crohn's disease. | 0 | Theoretical and Fundamental Chemistry |
For many years after the new art deco fronted building was opened in 1939 the work was carried out in laboratories fronting on Euston Street, London, NW1. These included three parallel four-story blocks of laboratories and offices with the basements being used for the heaviest equipment and for storage of samples. The Euston Street building was extended to the right of the main entrance making the address 81–103 Euston Street, with the laboratories behind being in Regnart Buildings and Euston Buildings which fronted on Stephenson Way. The extension was opened on 13 May 1959 by Sir Alexander Fleck. In the mid-1950s Prince Philip, Duke of Edinburgh toured all departments.
The laboratories were grouped in specialist sections, including analytical chemistry, corrosion, creep testing, electroplating, fatigue testing, general metallurgy, information library, mechanical testing, melting and casting, members liaison, metallography, metal working, physics (X-ray crystallography), and spectrography.
The laboratories were an excellent training ground both for assistants who studied for their qualifications part-time and for recent graduates from universities. As such members found that staff could be ideal recruits for industrial work. There were 150–200 staff and the average time for researchers to stay was about three years and they could then be found in industries in Britain and worldwide. From the late 1930s to the 1960s through the war and then post-war recovery the Director was Mr G. L. Bailey with Miss E. M. (Helen) Hills as his secretary. | 1 | Applied and Interdisciplinary Chemistry |
Ružička was born in Vukovar (until 1920 in the Kingdom of Hungary, Austro-Hungarian Empire, today in Croatia). His family of craftsmen and farmers was mostly of Croat origin, with a Czech great-grandparent, Ružička, and a great-grandmother and a great-grandfather from Austria. He lost his father, Stjepan, at the age of four, and his mother, Amalija Sever, took him and his younger brother Stjepan, to live in Osijek.
Ružička attended the classics program secondary school in Osijek. He changed his original idea of becoming a priest and switched to studying technical disciplines. Chemistry was his choice, probably because he hoped to get a position at the newly opened sugar refinery built in Osijek.
Owing to the excessive hardship of everyday and political life, he left and chose the High Technical School in Karlsruhe in Germany. He was a good student in areas he liked and that he thought would be necessary and beneficial in the future, which was organic chemistry. That is why his physical chemistry professor, Fritz Haber (Nobel laureate in 1918), opposed his summa cum laude degree. However, in the course of his studies, Ružička set up excellent cooperation with Hermann Staudinger (a Nobel laureate in 1953). Studying within Staudingers department, he obtained his doctoral degree in 1910, then moving to Zürich as Staudingers assistant. | 0 | Theoretical and Fundamental Chemistry |
On a crushing and screening plant, punch plates or perforated plates are mostly used on scalper vibrating screens, after raw products pass on grizzly bars. Most likely installed on a tensioned deck, punch plates offer excellent wear life for high-impact and high material flow applications. | 1 | Applied and Interdisciplinary Chemistry |
Conventional cytogenetic testing cannot offer the gene-level resolution required to predict the outcome of a pregnancy and whole genome deep sequencing is not practical for routine prenatal diagnosis. Whole-genome jumping library could complement conventional prenatal testing. This novel method was successfully applied to identify a case of CHARGE syndrome. | 1 | Applied and Interdisciplinary Chemistry |
To maximize the purity of product water, EDI feedwater needs pre-treatment, usually done via reverse osmosis. When fed with feedwater that is low in total dissolved solids (e.g., purified by RO), the product can reach very high purity levels. The contents of the feedwater must be kept within certain parameters to prevent damage to the EDI instrument.
Common feedwater quality concerns are:
* Hardness, which is often limited to 1 part per million (ppm) of CaCO or corresponding molecule, with limited exceptions up to 2 ppm.
* Silica content (SiO), which generally must be no more than 1 ppm in most EDI cells or 2 ppm in thin-cell modules.
* CO, which must be monitored to prevent excessive loading of anion exchange resin.
* TOC, which can foul resins and membranes, must be minimized.
* Chlorine, ozone, and other oxidizers can oxidize resins and membranes and create permanent damage, and must be minimized. | 0 | Theoretical and Fundamental Chemistry |
The Condor Dense Medium Separator (DMS) is a multi-stage, high efficiency media separation machine for mineral processing operations at the rougher and scavenger stage. It is typically used in a pre-concentration duty prior to processing or milling to reject barren material. The unit is manufactured with either two or three stages of separation depending on the media with one or two valuable densities resulting, while the unit can produce up to four products from one dense medium vessel altogether. The Condor DMS can take a larger feed particle size compared to a DMS cyclone of the same diameter and capacity, and is capable of handling higher sinks or floats loading without affecting performance. The valuable dense material (or sinks) can be combined or separated at the final stage and is then pumped onto the next process in the circuit. Sepro Mineral Systems Corp. supplies customizable DMS Plants for a wide variety of application requirements. Sepro's standard two product (concentrate, tailings) DMS Plant utilizes a two-stage Condor Separator and single density medium circuit, while the three product (concentrate, middlings, tailings) DMS Plant utilizes a three-stage Condor Separator and two medium circuits at high and low density. | 1 | Applied and Interdisciplinary Chemistry |
FLAG-tag, or FLAG octapeptide, or FLAG epitope, is a peptide protein tag that can be added to a protein using recombinant DNA technology, having the sequence DYKDDDDK (where D=aspartic acid, Y=tyrosine, and K=lysine). It is one of the most specific tags and it is an artificial antigen to which specific, high affinity monoclonal antibodies have been developed and hence can be used for protein purification by affinity chromatography and also can be used for locating proteins within living cells. FLAG-tag has been used to separate recombinant, overexpressed protein from wild-type protein expressed by the host organism. FLAG-tag can also be used in the isolation of protein complexes with multiple subunits, because FLAG-tag's mild purification procedure tends not to disrupt such complexes. FLAG-tag-based purification has been used to obtain proteins of sufficient purity and quality to carry out 3D structure determination by x-ray crystallography.
A FLAG-tag can be used in many different assays that require recognition by an antibody. If there is no antibody against a given protein, adding a FLAG-tag to a protein allows the protein to be studied with an antibody against the FLAG-tag sequence. Examples are cellular localization studies by immunofluorescence, immunoprecipitation or detection by SDS PAGE protein electrophoresis and Western blotting.
The peptide sequence of the FLAG-tag from the N-terminus to the C-terminus is: DYKDDDDK (1012 Da). Additionally, FLAG-tags may be used in tandem, commonly the 3xFLAG peptide: DYKDHD-G-DYKDHD-I-DYKDDDDK (with the final tag encoding an enterokinase cleavage site). FLAG-tag can be fused to the C-terminus or the N-terminus of a protein, or inserted within a protein. Some commercially available antibodies (e.g., M1/4E11) recognize the epitope only when FLAG-tag is present at the N-terminus. However, other available antibodies (e.g., M2) are position-insensitive. The tyrosine residue in the FLAG-tag can be sulfated when expressed on certain secreted proteins, which can affect antibody recognition of the FLAG epitope. The FLAG-tag can be used in conjunction with other affinity tags, for example a polyhistidine tag (His-tag), HA-tag or myc-tag. | 1 | Applied and Interdisciplinary Chemistry |
Different tissues of the human body may react differently to changes in telomeres. Telomere length is different in different tissues and cell types of the body. Developing a general telomere lengthening strategy that is effective in all tissues is a complex task; Also, understanding how different types of cells, organs and systems react to telomere manipulation is very important for developing safe and effective interventions. | 1 | Applied and Interdisciplinary Chemistry |
A phenomenon that is commonly presented as evidence for the existence of zero-point energy in vacuum is the Casimir effect, proposed in 1948 by Dutch physicist Hendrik Casimir, who considered the quantized electromagnetic field between a pair of grounded, neutral metal plates. The vacuum energy contains contributions from all wavelengths, except those excluded by the spacing between plates. As the plates draw together, more wavelengths are excluded and the vacuum energy decreases. The decrease in energy means there must be a force doing work on the plates as they move.
Early experimental tests from the 1950s onwards gave positive results showing the force was real, but other external factors could not be ruled out as the primary cause, with the range of experimental error sometimes being nearly 100%. That changed in 1997 with Lamoreaux conclusively showing that the Casimir force was real. Results have been repeatedly replicated since then.
In 2009, Munday et al. published experimental proof that (as predicted in 1961) the Casimir force could also be repulsive as well as being attractive. Repulsive Casimir forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction.
An interesting hypothetical side effect of the Casimir effect is the Scharnhorst effect, a hypothetical phenomenon in which light signals travel slightly faster than between two closely spaced conducting plates. | 0 | Theoretical and Fundamental Chemistry |
Denaturing gels are run under conditions that disrupt the natural structure of the analyte, causing it to unfold into a linear chain. Thus, the mobility of each macromolecule depends only on its linear length and its mass-to-charge ratio. Thus, the secondary, tertiary, and quaternary levels of biomolecular structure are disrupted, leaving only the primary structure to be analyzed.
Nucleic acids are often denatured by including urea in the buffer, while proteins are denatured using sodium dodecyl sulfate, usually as part of the SDS-PAGE process. For full denaturation of proteins, it is also necessary to reduce the covalent disulfide bonds that stabilize their tertiary and quaternary structure, a method called reducing PAGE. Reducing conditions are usually maintained by the addition of beta-mercaptoethanol or dithiothreitol. For a general analysis of protein samples, reducing PAGE is the most common form of protein electrophoresis.
Denaturing conditions are necessary for proper estimation of molecular weight of RNA. RNA is able to form more intramolecular interactions than DNA which may result in change of its electrophoretic mobility. Urea, DMSO and glyoxal are the most often used denaturing agents to disrupt RNA structure. Originally, highly toxic methylmercury hydroxide was often used in denaturing RNA electrophoresis, but it may be method of choice for some samples.
Denaturing gel electrophoresis is used in the DNA and RNA banding pattern-based methods temperature gradient gel electrophoresis (TGGE) and denaturing gradient gel electrophoresis (DGGE). | 1 | Applied and Interdisciplinary Chemistry |
Ekeberg analyzed a number of the minerals found at Ytterby and Falun. In 1802 he analyzed specimens of tantalite from Kimito, Finland, and of yttrotantalite from Ytterby, Sweden. He is credited with finding the element tantalum in both.
Ekeberg named the new element after the mythical Ancient Greek demigod Tantalus. According to legend, he was condemned to eternal frustration when he had to stand in water up to his neck, but the water receded as he attempted to drink. | 1 | Applied and Interdisciplinary Chemistry |
A relatively recent work (2006) by Fernández and Frenking (2006) summarized the trends in hyperconjugation among various groups of acyclic molecules, using energy decomposition analysis or EDA. Fernández and Frenking define this type of analysis as "...a method that uses only the pi orbitals of the interacting fragments in the geometry of the molecule for estimating pi interactions." For this type of analysis, the formation of bonds between various molecular moieties is a combination of three component terms. ΔE represents what Fernández and Frenking call a molecules “quasiclassical electrostatic attractions.” The second term, ΔE, represents the molecules Pauli repulsion. ΔE, the third term, represents stabilizing interactions between orbitals, and is defined as the sum of ΔE and ΔE. The total energy of interaction, ΔE, is the result of the sum of the 3 terms.
A group whose ΔE values were very thoroughly analyzed were a group of enones that varied in substituent.
Fernández and Frenking reported that the methyl, hydroxyl, and amino substituents resulted in a decrease in ΔE from the parent 2-propenal. Conversely, halide substituents of increasing atomic mass resulted in increasing ΔE. Because both the enone study and Hammett analysis study substituent effects (although in different species), Fernández and Frenking felt that comparing the two to investigate possible trends might yield significant insight into their own results. They observed a linear relationship between the ΔE values for the substituted enones and the corresponding Hammett constants. The slope of the graph was found to be -51.67, with a correlation coefficient of -0.97 and a standard deviation of 0.54. Fernández and Frenking conclude from this data that ..."the electronic effects of the substituents R on pi conjugation in homo- and heteroconjugated systems is similar and thus appears to be rather independent of the nature of the conjugating system.". | 0 | Theoretical and Fundamental Chemistry |
As shown in Figure 5, ketenyl anion has two major resonance structures: ketenyl form and ynolate form. Due to the resonance structures, alkali metal cations can be coordinated to either at central carbon atom or terminal oxygen atom depending on its electronic structure. A series of structural analysis revealed both ketene and ynolate structures evenly contribute to the overall electronic structure of ketenyl anion.
From an example in Gessners paper, the crystal structure of the ketenyl anion K[PPh(=S)CCO] had the bond length of C-C bond (1.245 Å) and C-O bond (1.215 Å). By comparing these bond length with Pyykkős analysis on bond, C-C bond is in between double bond and triple bond whereas C-O bond is in between single bond and double bond. In natural bond orbital (NBO) analysis, Wiberg bond index is found to be 2.06 and 1.72 for C-C bond and C-O bond, respectively. These values also suggests that both double and triple bond character for C-C bond (range of 1.20 - 1.34 Å) and both single bond and double bond character for C-O bond (range of 1.24 - 1.38 Å). The characteristic of allene-like (C=C=C) structure is also applied other ketenyl anion compounds so far. Inoue's silica-ketenyl anion product, shown in Figure 3, had Wiberg bond index of 1.68 and 1.76 for Si-C bond and C-O bond, respectively. Their bond indices demonstrate that both Si-C and C-O bonds have part of double bond character that contributes of Si=C=O structure.
This ketenyl anion can dimerize in solid state as oxygen atoms interacts with alkali metal cation. This dimer can be broken up by adding M(18-crown-6) (where M = alkali metal cation), resulting in isolation of single ketenyl anion structure. Intrinsic bond orbitals (IBO) of the molecule [K(PPh(=S)CCO] reveal molecular orbital describing π-orbital of C-C and C-O and delocalized orbital on oxygen atom.
The stability of ketenyl anion is come from the decrease of charge on ketene carbon from parent ketene to ketenyl anion. In Gessner's study, parent ketenyl anion [H-C=C=O] has smaller positive charge (+4.0 e) on C compared to parent ketene [HC=C=O] (+7.0 e on C). This drops of charge makes the ketene less amphiphilic, leading to a more stable compound. | 0 | Theoretical and Fundamental Chemistry |
Chemfluence 2014 was a six-day technical extravaganza organized by the students of Department of Chemical Engineering from 25 February to 3 March 2014 under the theme of Energy and Environment. Several Workshops and Guest lectures were conducted to impart practical and technical knowledge to the budding Engineers. A National Conference on Energy and Environment, EECON14 was conducted as a part of Chemfluence14 3 March 2014. | 1 | Applied and Interdisciplinary Chemistry |
Metalloenzymes all have one feature in common, namely that the metal ion is bound to the protein with one labile coordination site. As with all enzymes, the shape of the active site is crucial. The metal ion is usually located in a pocket whose shape fits the substrate. The metal ion catalyzes reactions that are difficult to achieve in organic chemistry. | 1 | Applied and Interdisciplinary Chemistry |
*Research has shown that cinnamon oil, clove oil, and eugenol are effective snake repellents. Snakes will retreat when sprayed directly with these oils and will exit cargo or other confined spaces when these oils are introduced to the area.
*In ancient times the Greek historian Herodotus noted that Arabian harvesters of frankincense used burning resin from Styrax trees to repel poisonous snakes that lived in the trees.
*Camphor
*Moth balls
*The roots and other parts of Acacia polyacantha subsp. campylacantha emit chemical compounds that repel animals including rats, snakes and crocodiles. For snakes, roots are placed in the rafters of houses. | 1 | Applied and Interdisciplinary Chemistry |
mEH is widely expressed in virtually all mammalian cells as an endoplasmic reticulum-bound (i.e. microsomal-bound) enzyme with its C terminal catalytic domain facing the cytoplasm; in some tissues, however, mEH has been found bound to the cell surface plasma membrane with its catalytic domain facing the extracellular space. The primary function of mEH is to convert potentially toxic xenobiotics and other compounds that possess epoxide residues (which is often due to their initial metabolism by cytochrome P450 enzymes to epoxides) to diols. Epoxides are highly reactive electrophilic compounds that form adducts with DNA and proteins and also cause strand breaks in DHA; in consequence, epoxides can cause gene mutations, cancer, and the inactivation of critical proteins. The diols thereby formed are usually not toxic or far less toxic than their epoxide predecessors, are readily further metabolized, and ultimately excreted in the urine. mEH also metabolizes certain epoxides of polyunsaturated fatty acids such as the epoxyeicosatrienoic acids (EETs) but its activity in doing this is far less than that of sEH; mEH therefore may play a minor role, compared to sEH, in limiting the bioactivity of these cell signaling compounds (see microsomal epoxide hydrolase). | 1 | Applied and Interdisciplinary Chemistry |
UIT is highly controllable. Incorporating a programmable logic controller (PLC) or a Digital Ultrasonic Generator, the frequency and amplitude of UIT are easily set and maintained, thus removing a significant portion of operator dependency. UIT can also be mechanically controlled, thus providing repeatability of results from one application to the next. Examples of mechanical control employed with UIT include:
*CNC milling machines
*Lathes
*Robotic control
*Weld tractors
With these types of controlled applications, the surface finish of the work piece is highly controllable.
For many applications, UIT is most effectively employed by hand. The high portability of the UIT system enables travel to austere locations and hard to reach places. The flexibility that is facilitated by variations in the tool configuration (such as angle-peening-head) ensures that access to very tight locations is possible.
UIT's effectiveness has been illustrated on the following metals, among others:
*Aluminium (including sensitized Aluminium)
*Bronze
*Cobalt alloys
*Nickel alloys
*Steels
**Carbon steel
**Stainless steel
**High-strength low-alloy steel
**Manganese steel
*Titanium | 1 | Applied and Interdisciplinary Chemistry |
An Alkali-metal thermal to electric converter works by pumping something, usually sodium, though any Alkali metal will do, through, around, and over, a circuit. The heat evaporates the sodium at one end. This puts it at high pressure. It then passes through/over the Anode, releasing electrons, thus, charge. It then passes through an electrolyte to conduct it to the other side. This works because the electrolyte chosen can conduct Ions, but not electrons so well. At the Cathode, the Alkali metal gets its electrons back, effectively pumping electrons through the external circuit. The pressure from the electrolyte pushes it to a low-pressure vapor chamber, where it “cools off” to a liquid again. An electromagnetic pump, or a wick, takes this liquid sodium back to the hot side.
This device accepts a heat input in a range 900–1300 K and produces direct current with predicted device efficiencies of 15–40%. In the AMTEC, sodium is driven around a closed thermodynamic cycle between a high-temperature heat reservoir and a cooler reservoir at the heat rejection temperature. The unique feature of the AMTEC cycle is that sodium ion conduction between a high-pressure or -activity region and a low-pressure or -activity region on either side of a highly ionically conducting refractory solid electrolyte is thermodynamically nearly equivalent to an isothermal expansion of sodium vapor between the same high and low pressures. Electrochemical oxidation of neutral sodium at the anode leads to sodium ions, which traverse the solid electrolyte, and electrons, which travel from the anode through an external circuit, where they perform electrical work, to the low-pressure cathode, where they recombine with the ions to produce low-pressure sodium gas. The sodium gas generated at the cathode then travels to a condenser at the heat-rejection temperature of perhaps 400–700 K, where liquid sodium reforms. The AMTEC thus is an electrochemical concentration cell, which converts the work generated by expansion of sodium vapor directly into electric power.
The converter is based on the electrolyte used in the sodium–sulfur battery, sodium beta″-alumina, a crystalline phase of somewhat variable composition containing aluminum oxide, AlO, and sodium oxide, NaO, in a nominal ratio of 5:1, and a small amount of the oxide of a small-cation metal, usually lithium or magnesium, which stabilizes the beta″ crystal structure. The sodium beta″-alumina solid electrolyte (BASE) ceramic is nearly insulating with respect to transport of electrons and is a thermodynamically stable phase in contact with both liquid sodium and sodium at low pressure. | 0 | Theoretical and Fundamental Chemistry |
The first market for nanolattices may be small-scale, small-lot components for biomedical, electrochemical, microfluidic, and aerospace applications, which require highly customizable and extreme combinations of properties. In the aerospace industry, the application of nanolattice could make the aircraft lighter and save lots of energy. | 0 | Theoretical and Fundamental Chemistry |
Tandem mass spectrometry (Tandem MS or MS/MS) uses two mass analyzers in sequence to separate more complex mixtures of analytes. The advantage of tandem MS is that it can be much faster than other two-dimensional methods, with times ranging from milliseconds to seconds. Because there is no dilution with solvents in MS, there is less probability of interference, so tandem MS can be more sensitive and have a higher signal-to-noise ratio compared to other two-dimensional methods. The main disadvantage associated with tandem MS is the high cost of the instrumentation needed. Prices can range from $500,000 to over $1 million. Many form of tandem MS involve a mass selection step and a fragmentation step. The first mass analyzer can be programmed to only pass molecules of a specific mass-to-charge ratio. Then the second mass analyzer can fragment the molecule to determine its identity. This can be especially useful for separating molecules of the same mass (i.e. proteins of the same mass or molecular isomers). Different types of mass analyzers can be coupled to achieve varying effects. One example would be a TOF-Quadrupole system. Ions can be sequentially fragmented and/or analyzed in a quadrupole as they leave the TOF in order of increasing m/z. Another prevalent tandem mass spectrometer is the quadrupole-quadrupole-quadrupole (Q-Q-Q) analyzer. The first quadrupole separates by mass, collisions take place in the second quadrupole, and the fragments are separated by mass in the third quadrupole. | 0 | Theoretical and Fundamental Chemistry |
Levocetirizine is referred to as a non-sedating antihistamine as it does not enter the brain in significant amounts and is therefore unlikely to cause drowsiness. Cardiac safety with repolarization may be better than some other antihistamines, as levocetirizine does not significantly prolong the QT interval in healthy individuals. However, some people may still experience some slight sleepiness, headache, mouth dryness, lightheadedness, vision problems (mainly blurred vision), palpitations and fatigue. | 0 | Theoretical and Fundamental Chemistry |
Alessandro Volta, a contemporary physicist, believed that the effect was explicable not by any vital force but rather it was the presence of two different metals that was generating the electricity. Volta demonstrated his theory by creating the first chemical electric battery. Despite their differences in opinion, Volta named the phenomenon of the chemical generation of electricity "Galvanism" after Galvani. | 0 | Theoretical and Fundamental Chemistry |
* ASBMB Student Chapters Regional Meeting Award
* Outstanding Chapter Award
* Student Chapter Outreach Grant
* ASBMB Undergraduate Research Award
* Student Chapters Award | 1 | Applied and Interdisciplinary Chemistry |
Source: [https://www.rsc.org/Membership/Networking/InterestGroups/Electrochemistry/faradaymedal.asp RIC]
* 1977 Veniamin Grigorievich Levich (1917–1987)
* 1981 John O’M. Bockris
* 1983 Jean-Michel Savéant
* 1985 Michel Armand
* 1987 Heinz Gerischer (1919–1994)
* 1991 David A. J. Rand, CSIRO Division of Mineral Chemistry, Port Melbourne
* 1994 Stanley Bruckenstein, University at Buffalo
* 1995 Michael J. Weaver (1947–2002), Purdue University
* 1996 Adam Heller, University of Texas
* 1998 Wolf Vielstich, Universität Bonn
* 1999 Philippe Allongue, CNRS
* 2000 Alan Maxwell Bond (b. 1946), Monash University
* 2001 Michael Grätzel, École polytechnique fédérale de Lausanne
* 2002 Henry S. White, University of Utah
* 2003 (1942–2011), Universität Ulm
* 2004 Daniel A. Scherson, Case Western Reserve University
* 2005 Robert Mark Wightman, University of North Carolina
* 2006 Hubert H. Girault, École polytechnique fédérale de Lausanne
* 2007 Christian Amatore, CNRS
* 2008 Nathan Lewis, California Institute of Technology
* 2009 Reginald M. Penner, University of California, Irvine
* 2011 Héctor D. Abruña, Cornell University
* 2012 Zhong-Qun Tian, Xiamen University
* 2013 Nenad Markovic
* 2014 Masatoshi Osawa, Hokkaido University
* 2015 Richard M. Crooks, University of Texas at Austin
* 2016 Justin Gooding, University of New South Wales, Australia
* 2017 Marc Koper, Leiden University
* 2018 Yang Shao-Horn, MIT
* 2019 Martin Winter, Westfälische Wilhelms-Universität Münster
* 2020 Shirley Meng, University of California, San Diego
* 2021 Peter Strasser, Technical University of Berlin
* 2022 Beatriz Roldán Cuenya, Fritz-Haber-Institute, Berlin | 0 | Theoretical and Fundamental Chemistry |
Zuclopenthixol is available in three major preparations:
* As zuclopenthixol decanoate (Clopixol Depot, Cisordinol Depot), it is a long-acting intramuscular injection. Its main use is as a long-acting injection given every two or three weeks to people with schizophrenia who have a poor compliance with medication and suffer frequent relapses of illness. There is some evidence it may be more helpful in managing aggressive behaviour.
* As zuclopenthixol acetate (Clopixol-Acuphase, Cisordinol-Acutard), it is a shorter-acting intramuscular injection used in the acute sedation of psychotic inpatients. The effect peaks at 48–72 hours providing 2–3 days of sedation.
* As zuclopenthixol dihydrochloride (Clopixol, Cisordinol), it is a tablet used in the treatment of schizophrenia in those who are compliant with oral medication.
It is also used in the treatment of acute bipolar mania. | 0 | Theoretical and Fundamental Chemistry |
There is a lower limit for the length of the interconnect that will allow higher current carrying capability. It is known as "Blech length". Any wire that has a length below this limit will have a stretched limit for electromigration. Here, a mechanical stress buildup causes an atom back flow process which reduces or even compensates the effective material flow towards the anode. The Blech length must be considered when designing test structures to evaluate electromigration. This minimum length is typically some tens of microns for chip traces, and interconnections shorter than this are sometimes referred to as electromigration immortal. | 0 | Theoretical and Fundamental Chemistry |
Sumatriptan was the pioneer drug in this class. The second generation's triptans such as zolmitriptan, naratriptan, rizatriptan, almotriptan, eletriptan and frovatriptan soon became available.
Different triptans are available in different formulations and in different strengths (see table 2). They have been formulated as subcutaneous injections, oral tablets, orally disintegrating tablets, nasal spray and as rectal suppositories.
Delivery system of the triptans may play an important role in the onset of action. The selection of anti-migraine drug for patients depends on their symptoms. The first selective 5-HT agonist, sumatriptan, was first synthesized as a subcutaneous injection, then as an oral tablets and more recently as a nasal spray, it is also available in some countries as suppositories. The subcutaneous injection is the fastest way to stop a rapidly progressing migraine attack. The sumatriptan nasal spray provides faster onset of action than the tablets but it produces a similar headache response at 2 hours. Some patients prefer the nasal spray as it works more rapidly than the tablets and does not have as many adverse effects as the subcutaneous injection. Nasal spray is although not suitable for all patients, because some patients experience bad taste and lack of consistency of response. Zolmitriptan was developed with the strategy to create a more lipophilic compound, with faster absorption and better ability to cross the blood brain barrier than sumatriptan. It is available as tablets, orally disintegrating tablets and as nasal spray in some countries. Rizatriptan is available as tablets and orally disintegrating tablets but naratriptan, almotriptan, eletriptan and frovatriptan are only available in tablets, for now.
Specific enzyme not yet reported.</small>
The U.S. Food and Drug Administration (FDA) approved a new drug April 15, 2008, which is a combination of sumatriptan 85 mg and naproxen 500 mg (NSAID).
Triptans and NSAIDs work on distinct mechanism involved in migraine and therefore may offer improved treatment when administrated together. | 1 | Applied and Interdisciplinary Chemistry |
Sepro Agglomeration Drums are specifically designed to prepare feeds with high fines content on Gold and Base Metal heap loading operations. Processes where a Sepro Agglomeration Drum can be utilized include gold, copper, uranium and nickel laterite. The action in the agglomeration drum, combined with small additions of cement or lime, binds the fines into a "pelletised" product, which can be heaped and leached out without "pooling" and "channeling" caused by loss of heap permeability due to blinding by fines. The machine uses flexible rubber liners to prevent build up without the use of lifter bars and is adjustable on a pivotable base frame. Shell supported agglomerators such as the Sepro PTD Agglomeration Drum minimize stress on the shell by spreading the power drive over the full length of the unit. | 1 | Applied and Interdisciplinary Chemistry |
The poly(A) tail acts as the binding site for poly(A)-binding protein. Poly(A)-binding protein promotes export from the nucleus and translation, and inhibits degradation. This protein binds to the poly(A) tail prior to mRNA export from the nucleus and in yeast also recruits poly(A) nuclease, an enzyme that shortens the poly(A) tail and allows the export of the mRNA. Poly(A)-binding protein is exported to the cytoplasm with the RNA. mRNAs that are not exported are degraded by the exosome. Poly(A)-binding protein also can bind to, and thus recruit, several proteins that affect translation, one of these is initiation factor-4G, which in turn recruits the 40S ribosomal subunit. However, a poly(A) tail is not required for the translation of all mRNAs. Further, poly(A) tailing (oligo-adenylation) can determine the fate of RNA molecules that are usually not poly(A)-tailed (such as (small) non-coding (sn)RNAs etc.) and thereby induce their RNA decay. | 1 | Applied and Interdisciplinary Chemistry |
The salt balances are calculated for each soil reservoir separately. They are based on their water balances, using the salt concentrations of the incoming and outgoing water. Some concentrations must be given as input data, like the initial salt concentrations of the water in the different soil reservoirs, of the irrigation water and of the incoming groundwater in the aquifer. The concentrations are expressed in terms of electric conductivity (EC in dS/m). When the concentrations are known in terms of g salt/L water, the rule of thumb: 1 g/L -> 1.7 dS/m can be used. Usually, salt concentrations of the soil are expressed in ECe, the electric conductivity of an extract of a saturated soil paste. In Sahysmod, the salt concentration is expressed as the EC of the soil moisture when saturated under field conditions. As a rule, one can use the conversion rate EC : ECe = 2 : 1. The principles used are correspond to those described in the article soil salinity control.
Salt concentrations of outgoing water (either from one reservoir into the other or by subsurface drainage) are computed on the basis of salt balances, using different leaching or salt mixing efficiencies to be given with the input data. The effects of different leaching efficiencies can be simulated varying their input value.
If drain or well water is used for irrigation, the method computes the salt concentration of the mixed irrigation water in the course of the time and the subsequent effect on the soil and ground water salinity, which again influences the salt concentration of the drain and well water. By varying the fraction of used drain or well water (through the input), the long-term effect of different fractions can be simulated.
The dissolution of solid soil minerals or the chemical precipitation of poorly soluble salts is not included in the computation method. However, but to some extent, it can be accounted for through the input data, e.g. increasing or decreasing the salt concentration of the irrigation water or of the incoming water in the aquifer. In a future version, the precipitation of gypsum may be introduced. | 0 | Theoretical and Fundamental Chemistry |
During the 2000 Presidential Election, Lee has been a supporter of the Pan-green coalition which advocates Taiwan independence. In the last week of the election he announced his support for the candidacy of Chen Shui-bian who subsequently won over James Soong. Chen intended to nominate Lee to become Premier. Lee has been the President of the Academia Sinica since 1994 and renounced his U.S. citizenship to take the post. As president of Academia Sinica he presided over the creation of the Taiwanese history textbook Knowing Taiwan.
At the request of Chen, Lee was the Republic of Chinas representative in the 2002 APEC leaders summit in Mexico. (Presidents of the Republic of China have been barred from joining the APEC summits because of objections from the People's Republic of China.) Lee represented Chen again in the 2003 and 2004 APEC summits in Thailand and Chile, respectively.
In January 2004, he and industrial tycoon Wang Yung-ching and theatre director Lin Hwai-min issued a joint statement to both Chen Shui-bian and Lien Chan. He backed Chen again in the 2004 elections when he issued a statement of support for the DPP on 17 March, three days before polls opened. Lee was then elected President of the International Council for Science in 2008, to start his term in 2011.
During the 2012 Republic of China presidential elections, Lee expressed his support for DPP candidate Tsai Ing-wen. In early 2016, he appeared and addressed a rally by New Power Party-a party formed by student activists involved in the Sunflower Movement. | 0 | Theoretical and Fundamental Chemistry |
Around two dozen chemical elements are essential to various kinds of biological life. Most rare elements on Earth are not needed by life (exceptions being selenium and iodine), while a few common ones (aluminum and titanium) are not used. Most organisms share element needs, but there are a few differences between plants and animals. For example, ocean algae use bromine, but land plants and animals do not seem to need any. All animals require sodium, but is not an essential element for plants. Plants need boron and silicon, but animals may not (or may need ultra-small amounts).
Just six elements—carbon, hydrogen, nitrogen, oxygen, calcium and phosphorus—make up almost 99% of the mass of living cells, including those in the human body (see composition of the human body for a complete list). In addition to the six major elements that compose most of the human body, humans require smaller amounts of possibly 18 more. | 1 | Applied and Interdisciplinary Chemistry |
The hydrophobicity of a compound can give scientists an indication of how easily a compound might be taken up in groundwater to pollute waterways, and its toxicity to animals and aquatic life. Partition coefficient can also be used to predict the mobility of radionuclides in groundwater. In the field of hydrogeology, the octanol–water partition coefficient K is used to predict and model the migration of dissolved hydrophobic organic compounds in soil and groundwater. | 0 | Theoretical and Fundamental Chemistry |
TCF7L2 modulates pancreatic islet β-cell function strongly implicating its significant association with GDM risk. T alleles of rs7903146 and rs1799884 TCF7L2 polymorphisms increase susceptibility to GDM in the Chinese Han population. | 1 | Applied and Interdisciplinary Chemistry |
Altszyler et al. (2017) have shown that these ultrasensitivity measures can be linked by the following equation:
where denoted the mean value of the variable x over the range [a,b]. | 1 | Applied and Interdisciplinary Chemistry |
A molecule may be nonpolar either when there is an equal sharing of electrons between the two atoms of a diatomic molecule or because of the symmetrical arrangement of polar bonds in a more complex molecule. For example, boron trifluoride (BF) has a trigonal planar arrangement of three polar bonds at 120°. This results in no overall dipole in the molecule.
Carbon dioxide (CO) has two polar C=O bonds, but the geometry of CO is linear so that the two bond dipole moments cancel and there is no net molecular dipole moment; the molecule is nonpolar.
Examples of household nonpolar compounds include fats, oil, and petrol/gasoline.
In the methane molecule (CH) the four C−H bonds are arranged tetrahedrally around the carbon atom. Each bond has polarity (though not very strong). The bonds are arranged symmetrically so there is no overall dipole in the molecule. The diatomic oxygen molecule (O) does not have polarity in the covalent bond because of equal electronegativity, hence there is no polarity in the molecule. | 0 | Theoretical and Fundamental Chemistry |
The project generated widespread media attention and a discussion of appropriate uses of biotechnology. As a result of the controversy, Kickstarter decided to prohibit genetically modified organisms as rewards to project backers.
Though the Animal and Plant Health Inspection Service (APHIS) has shown no regulatory concerns about the project, some synthetic biologists and policy researchers have questioned the project's feasibility and impact on future oversight or public opinion of synthetic biology. In particular, if the company were to encourage backers to use a genetic DIY kit themselves, additional regulatory oversight would likely occur. | 1 | Applied and Interdisciplinary Chemistry |
Instead of solving Rayleighs equation, Hsiao-Lan Kuo came up with a necessary stability condition which had to be met in order for the fluid to be able to get unstable. To get to this criterion, Rayleighs equation was rewritten and the boundary conditions of the flow field are used.
The first step is to divide Rayleigh's equation by and multiplying the equation by the complex conjugate of .
In the last step, is multiplied with its complex conjugate leading to the following equality is used: . For the solution of Rayleigh's equation to exist, both the real and imaginary part of the equation above need to be equal to zero. | 1 | Applied and Interdisciplinary Chemistry |
Strader and colleagues designed the first GPCR which could be activated only by a synthetic compound and has gradually been gaining momentum. The first international RASSL meeting was scheduled for April 6, 2006. A simple example of the use of a RASSL system in behavioral genetics was illustrated by Mueller et al. (2005) where they showed that expressing a RASSL receptor in sweet taste cells of the mouse tongue led to a strong preference for oral consumption of the synthetic ligand, whereas expressing the RASSL in bitter taste cells caused dramatic taste aversion for the same compound.
The attenuating effects of the hM4Di-DREADD were originally explored in 2007, before being confirmed in 2014. | 1 | Applied and Interdisciplinary Chemistry |
Another strategy that has been explored is the stabilization of reactions that develop partial negative charges in the transition state. Examples of successful applications are most commonly reactions that are approximated concerted and pericyclic in nature. During the course of the reaction, one fragment develops partial negative character and the transition state can be stabilized by accepting hydrogen bond(s).
A demonstrative example is the catalysis of Claisen rearrangements of ester-substituted allyl vinyl ethers reported by the Jacobsen research group. A chiral guanidinium catalyst was found to successfully promote the reaction near room temperature with high enantioselectivity. During the transition state, the fragment coordinated to the amidinium catalyst develops partial anionic character due to the electronegativity of the oxygen and the electron-withdrawing ester group. This increases the strength of hydrogen bonding and lowers the transition state energy, thus accelerating the reaction.
Similarly, negative charge can develop in cycloaddition reactions such as the Diels-Alder reaction, when the partners are appropriately substituted. As a representative example, Rawal and coworkers developed a chiral catalyst based on α,α,α,α-tetraaryl-1,3-dioxolane-4,5-dimethanol (TADDOL) that could catalyze Diels-Alder reactions. In the following example, the reaction with a highly electron-rich diene and an electron-poor dienophile is thought to develop significant negative charge on the enal fragment, and is the transition state is stabilized by increased hydrogen bonding to the TADDOL (Ar = 1-naphthyl). | 0 | Theoretical and Fundamental Chemistry |
Whether or not the principle of maximum power efficiency can be considered the fourth law of thermodynamics and the fourth principle of energetics is moot. Nevertheless, H.T. Odum also proposed a corollary of maximum power as the organisational principle of evolution, describing the evolution of microbiological systems, economic systems, planetary systems, and astrophysical systems. He called this corollary the maximum empower principle. This was suggested because, as S.E. Jorgensen, M.T. Brown, H.T. Odum (2004) note,
C. Giannantoni may have confused matters when he wrote "The "Maximum Em-Power Principle" (Lotka–Odum) is generally considered the "Fourth Thermodynamic Principle" (mainly) because of its practical validity for a very wide class of physical and biological systems" (C. Giannantoni 2002, § 13, p. 155). Nevertheless, Giannantoni has proposed the Maximum Em-Power Principle as the fourth principle of thermodynamics (Giannantoni 2006).
The preceding discussion is incomplete. The "maximum power" was discovered several times independently, in physics and engineering, see: Novikov (1957), El-Wakil (1962), and Curzon and Ahlborn (1975). The incorrectness of this analysis and design evolution conclusions was demonstrated by Gyftopoulos (2002). | 0 | Theoretical and Fundamental Chemistry |
An exopolymer is a biopolymer that is secreted by an organism into the environment (i.e. external to the organism). These exopolymers include the biofilms produced by bacteria to anchor them and protect them from environmental conditions. One type of expolymer, Transparent Exopolymers (TEP), found in both marine and aquatic ecosystems, are planktonic acidic polysaccharides of a gel-like consistency, originally defined by their ability to be stained visible by acidic Alcian Blue. Their free-floating characteristic sets TEPs aside from other extracellular polymeric substance subgroups where exopolymers exists as cell coating, dissolved slime or as part of biofilm matrices.
The formation of Transparent Exopolymer Particles(TEP) is mainly due to the abiotic coagulation of dissolved carbohydrates, which is secreted by the phytoplankton communities. Transparent Exopolymer Particles (TEP) have the ability to form larger aggregates because of their strong surface active properties or “stickiness”. This particular property of TEP allows them to perform as a glue matrix for other solid particles including detritus.
Transparent Exopolymer Particles (TEP) is also a carbon source for bacteria, which plays a significant role in affecting the food web structure and the carbon cycle in the ocean. Additionally, the conversion of dissolved organic carbon (DOC) to particulate organic carbon (POC) is an aggregation process that is due to TEP formation. | 1 | Applied and Interdisciplinary Chemistry |
None of the proposals were accepted immediately, and many contemporary chemists found it too abstract to have any meaningful value. Of those chemists that proposed their categorizations, Mendeleev strove to back his work and promote his vision of periodicity, Meyer did not promote his work very actively, and Newlands did not make a single attempt to gain recognition abroad.
Both Mendeleev and Meyer created their respective tables for their pedagogical needs; the difference between their tables is well explained by the fact that the two chemists sought to use a formalized system to solve different problems. Mendeleevs intent was to aid composition of his textbook, Foundations of Chemistry, whereas Meyer was rather concerned with presentation of theories. Mendeleevs predictions emerged outside of the pedagogical scope in the realm of journal science, while Meyer made no predictions at all and explicitly stated his table and his textbook it was contained in, Modern Theories, should not be used for prediction in order to make the point to his students to not make too many purely theoretically constructed projections.
Mendeleev and Meyer differed in temperament, at least when it came to promotion of their respective works. Boldness of Mendeleevs predictions was noted by some contemporary chemists, however skeptical they may have been. Meyer referred to Mendeleevs "boldness" in an edition of Modern Theories, whereas Mendeleev mocked Meyers indecisiveness to predict in an edition of Foundations of Chemistry'. | 1 | Applied and Interdisciplinary Chemistry |
During the synthesis of eukaryotic ribosomes, four mature ribosomal RNAs (the 5S, 5.8S, 18S, and 25S) must be synthesized. Three of these rRNAs (5.8S, 18S, and 25S) come from a single pre-rRNA known as the 35S. Although many of the intermediates in this rRNA processing pathway have been identified in the last thirty years, there are still a number of proteins involved in this process whose specific function is unknown. | 1 | Applied and Interdisciplinary Chemistry |
The IUBMB unites biochemists and molecular biologists in 75 countries that belong to the IUBMB as an "Adhering Body" or "Associate Adhering Body" represented by a biochemical society, a national research council or an academy of sciences. It also represents the regional organizations, Federation of Asian Oceanian Biochemists and Molecular Biologists (FAOBMB), Federation of European Biochemical Societies (FEBS), and Pan-American Society for Biochemistry and Molecular Biology (PABMB). | 1 | Applied and Interdisciplinary Chemistry |
Unlike the proofreading mechanisms of DNA polymerase those of RNAP have only recently been investigated. Proofreading begins with separation of the mis-incorporated nucleotide from the DNA template. This pauses transcription. The polymerase then backtracks by one position and cleaves the dinucleotide that contains the mismatched nucleotide. In the RNA polymerase this occurs at the same active site used for polymerization and is therefore markedly different from the DNA polymerase where proofreading occurs at a distinct nuclease active site.
The overall error rate is around 10 to 10. | 1 | Applied and Interdisciplinary Chemistry |
Installation of porous pavements is no more difficult than that of dense pavements, but has different specifications and procedures which must be strictly adhered to. Nine different families of porous paving materials present distinctive advantages and disadvantages for specific applications. Here are examples: | 1 | Applied and Interdisciplinary Chemistry |
Methylene blue is a monoamine oxidase inhibitor (MAOI), and if infused intravenously at doses exceeding 5 mg/kg, may precipitate serious serotonin toxicity, serotonin syndrome, if combined with any selective serotonin reuptake inhibitors (SSRIs) or other serotonin reuptake inhibitor (e.g., duloxetine, sibutramine, venlafaxine, clomipramine, imipramine).
It causes hemolytic anemia in carriers of the G6PD (favism) enzymatic deficiency. | 0 | Theoretical and Fundamental Chemistry |
Live cell imaging and proteomic studies have allowed researchers at the centre to gain fresh understanding of protein function and cell behaviour.
The centre is studying many aspects of the cell cycle, including the way in which chromosomes replicate and separate during cell division and how DNA damage is detected. Failure of these events can lead to major faults within a genome, potentially leading to the rise of cancerous cells. The centre is also investigating how DNA is tightly wound and compacted so that it can fit into the nuclei of eukaryotic cells, as well as the protein-DNA complexes that are involved in this packaging. The controlled unravelling of DNA is an important step in the regulation of gene function. | 1 | Applied and Interdisciplinary Chemistry |
To produce hydrogel fiber, the solidification of the pregel solution is the most important step. The pregel solution needs to be solidified while maintaining its fibrous shape. To achieve this, several methods based on chemical crosslinking, phase change, rheological property change have been developed. | 0 | Theoretical and Fundamental Chemistry |
The U.S. offers chemistry education degrees at the undergraduate and graduate levels. The following degrees are offered:
* Bachelor of Science in Chemistry Education
* Master of Science in Chemistry Education
* PhD in Chemistry Education
Additionally, colleges and universities offer chemistry degrees with a specialization in chemistry education. Some examples are:
* Bachelor of Science in Chemistry with Specialization in Chemical Education - University of Virginia
* Masters of Art in Chemistry with an Emphasis in Chemical Education - University of California Santa Barbara
*A compendium of graduate programs in chemistry that award M.S. and Ph.D. degrees for research on teaching and learning of chemistry can be found at https://sites.google.com/miamioh.edu/bretzsl/cer-resources/cer-graduate-programs
Undergraduate students who are interested in chemistry can major in the following areas:
* Chemistry
* Chemical engineering
* Biochemistry
* Environmental Chemistry
* Analytical chemistry
* Forensic Chemistry | 1 | Applied and Interdisciplinary Chemistry |
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