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UV degradation is one form of polymer degradation that affects plastics exposed to sunlight. The problem appears as discoloration or fading, cracking, loss of strength or disintegration. The effects of attack increase with exposure time and sunlight intensity. The addition of UV absorbers inhibits the effect.
Sensitive polymers include thermoplastics and speciality fibers like aramids. UV absorption leads to chain degradation and loss of strength at sensitive points in the chain structure. Aramid rope must be shielded with a sheath of thermoplastic if it is to retain its strength.
Many pigments and dyes absorb UV and change colour, so paintings and textiles may need extra protection both from sunlight and fluorescent lamps, two common sources of UV radiation. Window glass absorbs some harmful UV, but valuable artifacts need extra shielding. Many museums place black curtains over watercolour paintings and ancient textiles, for example. Since watercolours can have very low pigment levels, they need extra protection from UV. Various forms of picture framing glass, including acrylics (plexiglass), laminates, and coatings, offer different degrees of UV (and visible light) protection. | 8 | Ultraviolet Radiation |
Applications:
* The rotary filter is most suitable for continuous operation on large quantities of slurry.
* If the slurry contains considerable amount of solids, that is, in the range of 15-30%.
* Examples of pharmaceutical applications include the collection of calcium carbonate, magnesium carbonate and starch.
* The separation of the mycelia from the fermentation liquor in the manufacture of antibiotics.
* block and instant yeast production. | 5 | Separation Processes |
Sizing of a UV system is affected by three variables: flow rate, lamp power, and UV transmittance in the water. Manufacturers typically developed sophisticated computational fluid dynamics (CFD) models validated with bioassay testing. This involves testing the UV reactor's disinfection performance with either MS2 or T1 bacteriophages at various flow rates, UV transmittance, and power levels in order to develop a regression model for system sizing. For example, this is a requirement for all public water systems in the United States per the EPA UV manual.
The flow profile is produced from the chamber geometry, flow rate, and particular turbulence model selected. The radiation profile is developed from inputs such as water quality, lamp type (power, germicidal efficiency, spectral output, arc length), and the transmittance and dimension of the quartz sleeve. Proprietary CFD software simulates both the flow and radiation profiles. Once the 3D model of the chamber is built, it is populated with a grid or mesh that comprises thousands of small cubes.
Points of interest—such as at a bend, on the quartz sleeve surface, or around the wiper mechanism—use a higher resolution mesh, whilst other areas within the reactor use a coarse mesh. Once the mesh is produced, hundreds of thousands of virtual particles are "fired" through the chamber. Each particle has several variables of interest associated with it, and the particles are "harvested" after the reactor. Discrete phase modeling produces delivered dose, head loss, and other chamber-specific parameters. | 8 | Ultraviolet Radiation |
Small molecule inhibitors have been reported for both OGT and OGA that function in cells or in vivo. OGT inhibitors result in a global decrease of O-GlcNAc while OGA inhibitors result in a global increase of O-GlcNAc; these inhibitors are not able to modulate O-GlcNAc on specific proteins.
Inhibition of the hexosamine biosynthetic pathway is also able to decrease O-GlcNAc levels. For instance, glutamine analogues azaserine and 6-diazo-5-oxo-L-norleucine (DON) can inhibit GFAT, though these molecules may also non-specifically affect other pathways. | 6 | Carbohydrates |
* AMEL Active Matrix Electroluminescence
* TFEL Thin Film Electroluminescence
* TDEL Thick Dielectric Electroluminescence | 0 | Luminescence |
The uranium is then stripped from the DEHPA/kerosene solution with hydrochloric acid, hydrofluoric acid, or carbonate solutions. Sodium carbonate solutions effectively strip uranium from the organic layer, but the sodium salt of DEHPA is somewhat soluble in water, which can lead to loss of the extractant. | 5 | Separation Processes |
Cryo-adsorption is a method used for hydrogen storage where gaseous hydrogen at cryogenic temperatures (150—60 K) is physically adsorbed on porous material, mostly activated carbon. The achievable storage density is between liquid-hydrogen (LH) storage systems and compressed-hydrogen (CGH) storage systems. | 5 | Separation Processes |
The triple-alpha process is highly dependent on carbon-12 and beryllium-8 having resonances with slightly more energy than helium-4. Based on known resonances, by 1952 it seemed impossible for ordinary stars to produce carbon as well as any heavier element. Nuclear physicist William Alfred Fowler had noted the beryllium-8 resonance, and Edwin Salpeter had calculated the reaction rate for Be, C, and O nucleosynthesis taking this resonance into account. However, Salpeter calculated that red giants burned helium at temperatures of 2·10 K or higher, whereas other recent work hypothesized temperatures as low as 1.1·10 K for the core of a red giant.
Salpeters paper mentioned in passing the effects that unknown resonances in carbon-12 would have on his calculations, but the author never followed up on them. It was instead astrophysicist Fred Hoyle who, in 1953, used the abundance of carbon-12 in the universe as evidence for the existence of a carbon-12 resonance. The only way Hoyle could find that would produce an abundance of both carbon and oxygen was through a triple-alpha process with a carbon-12 resonance near 7.68 MeV, which would also eliminate the discrepancy in Salpeters calculations.
Hoyle went to Fowlers lab at Caltech and said that there had to be a resonance of 7.68 MeV in the carbon-12 nucleus. (There had been reports of an excited state at about 7.5 MeV.) Fred Hoyles audacity in doing this is remarkable, and initially, the nuclear physicists in the lab were skeptical. Finally, a junior physicist, Ward Whaling, fresh from Rice University, who was looking for a project decided to look for the resonance. Fowler permitted Whaling to use an old Van de Graaff generator that was not being used. Hoyle was back in Cambridge when Fowler's lab discovered a carbon-12 resonance near 7.65 MeV a few months later, validating his prediction. The nuclear physicists put Hoyle as first author on a paper delivered by Whaling at the summer meeting of the American Physical Society. A long and fruitful collaboration between Hoyle and Fowler soon followed, with Fowler even coming to Cambridge.
The final reaction product lies in a 0+ state (spin 0 and positive parity). Since the Hoyle state was predicted to be either a 0+ or a 2+ state, electron–positron pairs or gamma rays were expected to be seen. However, when experiments were carried out, the gamma emission reaction channel was not observed, and this meant the state must be a 0+ state. This state completely suppresses single gamma emission, since single gamma emission must carry away at least 1 unit of angular momentum. Pair production from an excited 0+ state is possible because their combined spins (0) can couple to a reaction that has a change in angular momentum of 0. | 3 | Nuclear Fusion |
The absence of fructose-1-phosphate aldolase (aldolase B) results in the accumulation of fructose 1 phosphate in hepatocytes, kidney and small intestines. An accumulation of fructose-1-phosphate following fructose ingestion inhibits glycogenolysis (breakdown of glycogen) and gluconeogenesis, resulting in severe hypoglycemia. It is symptomatic resulting in severe hypoglycemia, abdominal pain, vomiting, hemorrhage, jaundice, hepatomegaly, and hyperuricemia eventually leading to liver and/or kidney failure and death. The incidence varies throughout the world, but it is estimated at 1:55,000 (range 1:10,000 to 1:100,000) live births. | 6 | Carbohydrates |
It is a common observation that when oil and water are poured into the same container, they separate into two phases or layers, because they are immiscible. In general, aqueous (or water-based) solutions, being polar, are immiscible with non-polar organic solvents (cooking oil, chloroform, toluene, hexane etc.) and form a two-phase system. However, in an ABS, both immiscible components are water-based.
The formation of the distinct phases is affected by the pH, temperature and ionic strength of the two components, and separation occurs when the amount of a polymer present exceeds a certain limiting concentration (which is determined by the above factors). | 5 | Separation Processes |
Though uses of cord blood beyond blood and immunological disorders is speculative, some research has been done in other areas. Any such potential beyond blood and immunological uses is limited by the fact that cord cells are hematopoietic stem cells (which can differentiate only into blood cells), and not pluripotent stem cells (such as embryonic stem cells, which can differentiate into any type of tissue). Cord blood has been studied as a treatment for diabetes. However, apart from blood disorders, the use of cord blood for other diseases is not a routine clinical modality and remains a major challenge for the stem cell community.
Along with cord blood, Wharton's jelly and the cord lining have been explored as sources for mesenchymal stem cells (MSC), and as of 2015 had been studied in vitro, in animal models, and in early stage clinical trials for cardiovascular diseases, as well as neurological deficits, liver diseases, immune system diseases, diabetes, lung injury, kidney injury, and leukemia. | 2 | Tissue Engineering |
Initially, focusing on bone growth, subcutaneous pockets were used for bone prefabrication as a simple in vivo bioreactor model. The pocket is an artificially created space between varying levels of subcutaneous fascia. The location provides regenerative ques to the bioreactor implant but does not rely on pre-existing bone tissue as a substrate. Furthermore, these bioreactors may be wrapped with muscle tissue to encourage vascularization and bone growth. Another strategy is through the use of a periosteal flap wrapped around the bioreactor, or the scaffold itself to create an in vivo bioreactor. This strategy utilizes the guided bone regeneration treatment scheme, and is a safe method for bone prefabrication. These flap methods of packing the bioreactor within fascia, or wrapping it in tissue is effective, though somewhat random due to the non-directed vascularization these methods incur. The axial vascular bundle (AVB) strategy requires that an artery and vein are inserted in an in vitro bioreactor to transport growth factors, cells, and remove waste. This ultimately results in extensive vascularization of the bioreactor space and a vast improvement in growth capability. This vascularization, though effective, is limited by the surface contact that it can achieve between the scaffold and the capillaries filling the bioreactor space. Thus, a combination of the flap and AVB techniques can maximize the growth rate and vascular contact of the bioreactor as suggested by Han and Dai, by inserting a vascular bundle into a scaffold wrapped in either musculature or periosteum. If inadequate pre-existing vasculature is present in the growth site due to damage or disease, an arteriovenous loop (AVL) can be used. The AVL strategy requires a surgical connection be made between an artery of vein to form an arteriovenous fistula which is then placed within an in vitro bioreactor space containing a scaffold. A capillary network will form from this loop and accelerate the vascularization of new tissue. | 2 | Tissue Engineering |
Drug delivery refers to technology used to present a drug to a pre-determined region of the body for drug emission and absorption. Principles relating to route of administration, metabolism, site of specific targeting, and toxicity are most important within this field. Drugs administered orally (through mouth) are usually encapsulated in some structure in order to protect the drug from immune and biological responses. These structures aim to keep the drug intact until its site of action and release it at a correct dosage when exposed to a specific marker. Corn and potato starch are often used for this as they contain 60-80% amylopectin. They are mostly used in solid preparations: powders, granules, capsules, and tablets. As a natural polysaccharide, it has a compatible nature with anatomical structures and molecules. This prevents any sort of negative immune response, which is a highly controversial topic in drug delivery. Biodegradability of starch allows it to keep the drug intact until reaching its site of action. This allows the drug to avoid low pH situations such as the digestive system. Native starch can also be modified in physical, chemical, and enzymatic ways to improve mechanical or biochemical properties. Within drug delivery, physical modification include treatment under mechanical forces, heat, or pressure. Chemical modifications attempt to alter molecular structure which can include breaking or addition of bonds. Treating starch with enzymes can allow for increased water solubility. | 6 | Carbohydrates |
Brazil's National Health Surveillance Agency banned the use of tanning beds for cosmetic purposes in 2009, making that country the first to enact a ban. It followed a 2002 ban on minors using the beds. | 8 | Ultraviolet Radiation |
So far, we have assumed that the atoms do not interact with each other. Even though this is a reasonable assumption in the case of diamagnetic and paramagnetic substances, this assumption fails in the case of ferromagnetism, where the spins of the atom try to align with each other to the extent permitted by the thermal agitation. In this case, we have to consider the Hamiltonian of the ensemble of the atom. Such a Hamiltonian will contain all the terms described above for individual atoms and terms corresponding to the interaction among the pairs of the atom. Ising model is one of the simplest approximations of such pairwise interaction.
Here the two atoms of a pair are at . Their interaction is determined by their distance vector . In order to simplify the calculation, it is often assumed that interaction happens between neighboring atoms only and is a constant. The effect of such interaction is often approximated as a mean field and, in our case, the Weiss field. | 7 | Magnetic Ordering |
There are four major mechanisms to induce exchange interactions between two magnetic moments in a system: 1). Direct exchange 2). RKKY 3). Superexchange 4). Spin-Lattice. No matter which one is dominated, a general form of the exchange interaction can be written as
where are the site indexes and is the coupling constant that couples two multipole moments and . One can immediately find if is restricted to 1 only, the Hamiltonian reduces to conventional Heisenberg model.
An important feature of the multipolar exchange Hamiltonian is its anisotropy. The value of coupling constant is usually very sensitive to the relative angle between two multipoles. Unlike conventional spin only exchange Hamiltonian where the coupling constants are isotropic in a homogeneous system, the highly anisotropic atomic orbitals (recall the shape of the wave functions) coupling to the system's magnetic moments will inevitably introduce huge anisotropy even in a homogeneous system. This is one of the main reasons that most multipolar orderings tend to be non-colinear. | 7 | Magnetic Ordering |
The current American regulation for organ matching is centered on the national registry of organ donors after the National Organ Transplant Act was passed in 1984. This act was set in place to ensure equal and honest distribution, although it has been proven insufficient due to the large demand for organ transplants. Organ printing can assist in diminishing the imbalance between supply and demand by printing patient-specific organ replacements, all of which is unfeasible without regulation. The Food and Drug Administration (FDA) is responsible for regulation of biologics, devices, and drugs in the United States. Due to the complexity of this therapeutic approach, the location of organ printing on the spectrum has not been discerned. Studies have characterized printed organs as multi-functional combination products, meaning they fall between the biologics and devices sectors of the FDA; this leads to more extensive processes for review and approval. In 2016, the FDA issued draft guidance on the Technical Considerations for Additive Manufactured Devices and is currently evaluating new submissions for 3D printed devices. However, the technology itself is not advanced enough for the FDA to mainstream it directly. Currently, the 3D printers, rather than the finished products, are the main focus in safety and efficacy evaluations in order to standardize the technology for personalized treatment approaches. From a global perspective, only South Korea and Japan's medical device regulation administrations have provided guidelines that are applicable to 3D bio-printing.
There are also concerns with intellectual property and ownership. These can have a large impact on more consequential matters such as piracy, quality control for manufacturing, and unauthorized use on the black market. These considerations are focused more on the materials and fabrication processes; they are more extensively explained in the legal aspects subsection of 3D printing. | 2 | Tissue Engineering |
Two-dimensional examples are helpful in order to get some understanding about the origin of the competition between local rules and geometry in the large. Consider first an arrangement of identical discs (a model for a hypothetical two-dimensional metal) on a plane; we suppose that the interaction between discs is isotropic and locally tends to arrange the disks in the densest way as possible. The best arrangement for three disks is trivially an equilateral triangle with the disk centers located at the triangle vertices. The study of the long range structure can therefore be reduced to that of plane tilings with equilateral triangles. A well known solution is provided by the triangular tiling with a total compatibility between the local and global rules: the system is said to be "unfrustrated".
But now, the interaction energy is supposed to be at a minimum when atoms sit on the vertices of a regular pentagon. Trying to propagate in the long range a packing of these pentagons sharing edges (atomic bonds) and vertices (atoms) is impossible. This is due to the impossibility of tiling a plane with regular pentagons, simply because the pentagon vertex angle does not divide 2. Three such pentagons can easily fit at a common vertex, but a gap remains between two edges. It is this kind of discrepancy which is called "geometric frustration". There is one way to overcome this difficulty. Let the surface to be tiled be free of any presupposed topology, and let us build the tiling with a strict application of the local interaction rule. In this simple example, we observe that the surface inherits the topology of a sphere and so receives a curvature. The final structure, here a pentagonal dodecahedron, allows for a perfect propagation of the pentagonal order. It is called an "ideal" (defect-free) model for the considered structure. | 7 | Magnetic Ordering |
Several methods exist to detect the presence of O-GlcNAc and characterize the specific residues modified. | 6 | Carbohydrates |
Hot filtration can be used to separate "compound A" from both "impurity B" and some "insoluble matter C". This technique normally uses a single-solvent system as described above. When both "compound A" and "impurity B" are dissolved in the minimum amount of hot solvent, the solution is filtered to remove "insoluble matter C". This matter may be anything from a third impurity compound to fragments of broken glass. For a successful procedure, one must ensure that the filtration apparatus is hot in order to stop the dissolved compounds from crystallizing from the solution during filtration, thus forming crystals on the filter paper or funnel.
One way to achieve this is to heat a conical flask containing a small amount of clean solvent on a hot plate. A filter funnel is rested on the mouth, and hot solvent vapors keep the stem warm. Jacketed filter funnels may also be used. The filter paper is preferably fluted, rather than folded into a quarter; this allows quicker filtration, thus less opportunity for the desired compound to cool and crystallize from the solution.
Often it is simpler to do the filtration and recrystallization as two independent and separate steps. That is dissolve "compound A" and "impurity B" in a suitable solvent at room temperature, filter (to remove insoluble compound/glass), remove the solvent and then recrystallize using any of the methods listed above. | 5 | Separation Processes |
The optical emission properties of eFluor Nanocrystals are primarily dictated by their size, as discussed in the next section. There are at least two aspects to consider when discussing the "size" of a quantum dot: the physical size of the semiconductor structure, and the size of the entire quantum dot moiety including the associated ligands and hydrophilic coating. The size of the semiconductor structure is tabulated below, and reflects the diameter of the spherical quantum dot without ligands. eFluor Nanocrystals are rendered water-dispersable with a patented poly-ethylene glycol (PEG) lipid layer that functions as both a protective hydrophilic coating around the quantum dot, as well as reducing non-specific binding By dynamic light scattering measurements, the hydrodynamic radius of all eFluor Nanocrystals ranges from 10 to 13nm. | 0 | Luminescence |
Despite the many millions of dollars spent by the U.S. between 1952 and 1992 to produce a pure fusion weapon, no measurable success was ever achieved. In 1998, the U.S. Department of Energy (DOE) released a restricted data declassification decision stating that even if the DOE made a substantial investment in the past to develop a pure fusion weapon, "the U.S. is not known to have and is not developing a pure fusion weapon and no credible design for a pure fusion weapon resulted from the DOE investment". The power densities needed to ignite a fusion reaction still seem attainable only with the aid of a fission explosion, or with large apparatus such as powerful lasers like those at the National Ignition Facility, the Sandia Z-pinch machine, or various magnetic tokamaks. Regardless of any claimed advantages of pure fusion weapons, building those weapons does not appear to be feasible using currently available technologies and many have expressed concern that pure fusion weapons research and development would subvert the intent of the Nuclear Non-Proliferation Treaty and the Comprehensive Test Ban Treaty.
It has been claimed that it is possible to conceive of a crude, deliverable, pure fusion weapon, using only present-day, unclassified technology. The weapon design weighs approximately 3 tonnes, and might have a total yield of approximately 3 tonnes of TNT. The proposed design uses a large explosively pumped flux compression generator to produce the high power density required to ignite the fusion fuel. From the point of view of explosive damage, such a weapon would have no clear advantages over a conventional explosive, but the massive neutron flux could deliver a lethal dose of radiation to humans within a 500-meter radius (most of those fatalities would occur over a period of months, rather than immediately). | 3 | Nuclear Fusion |
Mercury lamps are the most common source of UV radiation due to their high efficiency. However, the use of mercury in these lamps poses disposal and environmental problems. On the contrary, excimer lamps based on rare gases are absolutely non-hazardous and excimer lamps containing halogen are more environmentally benign than mercury ones. | 8 | Ultraviolet Radiation |
Storeys research includes studies of enzyme properties, gene expression, protein phosphorylation, epigenetics, and cellular signal transduction mechanisms to seek out the basic principles of how organisms endure and flourish under extreme conditions. He is particularly known within the field of cryobiology for his studies of animals that can survive freezing, especially the frozen "frog-sicles" (Rana sylvatica) that have made his work popular with multiple TV shows and magazines. Storeys studies of the adaptations that allow frogs, insects, and other animals to survive freezing have made major advances in the understanding of how cells, tissues and organs can endure freezing. Storey was also responsible for the discovery that some turtle species are freeze tolerant: newly hatched painted turtles that spend their first winter on land (Chrysemys picta marginata & C. p. bellii). These turtles are unique as they are the only reptiles, and highest vertebrate life form, known to tolerate prolonged natural freezing of extracellular body fluids during winter hibernation. These advances may aid the development of organ cryopreservation technology. A second area of his research is metabolic rate depression - understanding the mechanisms by which some animals can reduce their metabolism and enter a state of hypometabolism or torpor that allows them to survive prolonged environmental stresses. His studies have identified molecular mechanisms that underlie metabolic arrest across phylogeny and that support phenomena including mammalian hibernation, estivation, and anoxia- and ischemia-tolerance. These studies hold key applications for medical science, particularly for preservation technologies that aim to extend the survival time of excised organs in cold or frozen storage. Additional applications include insights into hyperglycemia in metabolic syndrome and diabetes, and anoxic and ischemic damage caused by heart attack and stroke. Furthermore, Storey's lab has created several web based programs freely available for [http://www.kenstoreylab.com/research-tools/ data management, data plotting, and microRNA analysis]. | 1 | Cryobiology |
ABS is an excellent method to employ for the extraction of proteins/enzymes and other labile biomolecules from crude cell extracts or other mixtures. Most often, this technique is employed in enzyme technology during industrial or laboratory production of enzymes.
* They provide mild conditions that do not harm or denature unstable/labile biomolecules
* The interfacial stress (at the interface between the two layers) is far lower (400-fold less) than water-organic solvent systems used for solvent extraction, causing less damage to the molecule to be extracted
* The polymer layer stabilizes the extracted protein molecules, favouring a higher concentration of the desired protein in one of the layers, resulting in an effective extraction
* Specialised systems may be developed (by varying factors such as temperature, degree of polymerisation, presence of certain ions etc. ) to favour the enrichment of a specific compound, or class of compounds, into one of the two phases. They are sometimes used simultaneously with ion-exchange resins for better extraction
* Separation of the phases and the partitioning of the compounds occurs rapidly. This allows the extraction of the desired molecule before endogenous proteases can degrade them.
* These systems are amenable to scale-ups, from laboratory-sized set-ups to those that can handle the requirements of industrial production. They may be employed in continuous protein-extraction processes.
Specificity may be further increased by tagging ligands specific to the desired enzyme, onto the polymer. This results in a preferential binding of the enzyme to the polymer, increasing the effectiveness of the extraction.
One major disadvantage, however, is the cost of materials involved, namely high-purity dextrans employed for the purpose. However, other low-cost alternatives such as less refined dextrans, hydroxypropyl starch derivatives and high-salt solutions are also available. | 5 | Separation Processes |
It can be formulated as follows: take a d-dimensional lattice, and a set of spins of the unit length
each one placed on a lattice node.
The model is defined through the following Hamiltonian:
with
a coupling between spins. | 7 | Magnetic Ordering |
As for any other physical separation process, liberation is pre-requisite for possible separation. Liberation characteristics are well known and relatively easy to study for particulate lots in smaller size ranges, e.g. flotation feed and products. The analysis is essential for understanding the possible results of physical separation and relatively easy to conduct in laboratory on a couple of dozens of grams of sample which can be studied using optical methods or such as the QEMSCAN.
For larger particles above it is widely known for applications that are treated using density separation methods, such as coal or iron ore. Here, the washability analysis can be conducted on sample masses up to 10 tonnes in equipped laboratories. For sensor-based sorting, where laboratory methods can only tell about the liberation characteristics where the describing feature is the density (e.g. iron ore, coal), hand counting, single-particle tests and bulk tests can reveal the liberation characteristics of a bulk material: Hereby, only single particle tests reveal the true liberation, while hand counting and bulk testing give a result which also incorporates the separation efficiency of the type of analysis. More information on the testing procedures used in technical feasibility evaluation can be found in the respective chapter. | 5 | Separation Processes |
Adduct purification is a technique for preparing extremely pure simple organometallic compounds, which are generally unstable and hard to handle, by purifying a stable adduct with a Lewis acid and then obtaining the desired product from the pure adduct by thermal decomposition.
Epichem Limited is the licensee of the major patents in this field, and uses the trademark EpiPure to refer to adduct-purified materials; Professor Anthony Jones at Liverpool University is the initiator of the field and author of many of the important papers.
The choice of Lewis acid and of reaction medium is important; the desired organometallics are almost always air- and water-sensitive. Initial work was done in ether, but this led to oxygen impurities, and so more recent work involves tertiary amines or nitrogen-substituted crown ethers. | 5 | Separation Processes |
Ultraviolet radiation is used for very fine resolution photolithography, a procedure wherein a chemical called a photoresist is exposed to UV radiation that has passed through a mask. The exposure causes chemical reactions to occur in the photoresist. After removal of unwanted photoresist, a pattern determined by the mask remains on the sample. Steps may then be taken to "etch" away, deposit on or otherwise modify areas of the sample where no photoresist remains.
Photolithography is used in the manufacture of semiconductors, integrated circuit components, and printed circuit boards. Photolithography processes used to fabricate electronic integrated circuits presently use 193 nm UV and are experimentally using 13.5 nm UV for extreme ultraviolet lithography. | 8 | Ultraviolet Radiation |
Allison Hubel is an American mechanical engineer and cryobiologist who applies her expertise in heat transfer to study the cryopreservation of biological tissue. She is a professor of mechanical engineering at the University of Minnesota, where she directs the Biopreservation Core Resource and the Technological Leadership Institute, and is president-elect of the Society for Cryobiology. | 1 | Cryobiology |
The thickness of the ozone layer varies worldwide and is generally thinner near the equator and thicker near the poles. Thickness refers to how much ozone is in a column over a given area and varies from season to season. The reasons for these variations are due to atmospheric circulation patterns and solar intensity.
The majority of ozone is produced over the tropics and is transported towards the poles by stratospheric wind patterns. In the northern hemisphere these patterns, known as the Brewer–Dobson circulation, make the ozone layer thickest in the spring and thinnest in the fall. When ozone is produced by solar UV radiation in the tropics, it is done so by circulation lifting ozone-poor air out of the troposphere and into the stratosphere where the sun photolyzes oxygen molecules and turns them into ozone. Then, the ozone-rich air is carried to higher latitudes and drops into lower layers of the atmosphere.
Research has found that the ozone levels in the United States are highest in the spring months of April and May and lowest in October. While the total amount of ozone increases moving from the tropics to higher latitudes, the concentrations are greater in high northern latitudes than in high southern latitudes, with spring ozone columns in high northern latitudes occasionally exceeding 600 DU and averaging 450 DU whereas 400 DU constituted a usual maximum in the Antarctic before anthropogenic ozone depletion. This difference occurred naturally because of the weaker polar vortex and stronger Brewer–Dobson circulation in the northern hemisphere owing to that hemisphere’s large mountain ranges and greater contrasts between land and ocean temperatures. The difference between high northern and southern latitudes has increased since the 1970s due to the ozone hole phenomenon. The highest amounts of ozone are found over the Arctic during the spring months of March and April, but the Antarctic has the lowest amounts of ozone during the summer months of September and October, | 8 | Ultraviolet Radiation |
Printing materials must fit a broad spectrum of criteria, one of the foremost being biocompatibility. The resulting scaffolds formed by 3D printed materials should be physically and chemically appropriate for cell proliferation. Biodegradability is another important factor, and insures that the artificially formed structure can be broken down upon successful transplantation, to be replaced by a completely natural cellular structure. Due to the nature of 3D printing, materials used must be customizable and adaptable, being suited to wide array of cell types and structural conformations. | 2 | Tissue Engineering |
Researchers have begun to focus on decellularization for organ transplants since it reduces the chance of rejection to almost none. This process was used in the first successful stem-cell based organ transplant by removing the cells and MHC antigens from the donor organ. There are different ways to remove the cells from the organ which can include physical, chemical, and enzymatic treatments. This method is especially useful when trying to create a neo-heart because the heart needs to be created in a way where the structure remains. Since the stem cells used are currently not able to maintain a shape, researchers have started to look more into decellularization of existing organs to be able to perform successful transplant procedures without the problem of rejection. While this method may assist with the problem of rejection, donors are still needed to provide this structure to patients. | 2 | Tissue Engineering |
Minimise the lateral pressure of the strings by adjusting the alignment tine bar to avoid the string being cut off. Have ceramic tube place over each aligning tine bar to act as bearing surface for the strings. | 5 | Separation Processes |
An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce the H cation and the anion of the acid. | 4 | Acids + Bases |
Fructolysis refers to the metabolism of fructose from dietary sources. Though the metabolism of glucose through glycolysis uses many of the same enzymes and intermediate structures as those in fructolysis, the two sugars have very different metabolic fates in human metabolism. Unlike glucose, which is directly metabolized widely in the body, fructose is mostly metabolized in the liver in humans, where it is directed toward replenishment of liver glycogen and triglyceride synthesis. Under one percent of ingested fructose is directly converted to plasma triglyceride. 29% - 54% of fructose is converted in liver to glucose, and about a quarter of fructose is converted to lactate. 15% - 18% is converted to glycogen. Glucose and lactate are then used normally as energy to fuel cells all over the body.
Fructose is a dietary monosaccharide present naturally in fruits and vegetables, either as free fructose or as part of the disaccharide sucrose, and as its polymer inulin. It is also present in the form of refined sugars including granulated sugars (white crystalline table sugar, brown sugar, confectioner's sugar, and turbinado sugar), refined crystalline fructose , as high fructose corn syrups as well as in honey. About 10% of the calories contained in the Western diet are supplied by fructose (approximately 55 g/day).
Unlike glucose, fructose is not an insulin secretagogue, and can in fact lower circulating insulin. In addition to the liver, fructose is metabolized in the intestines, testis, kidney, skeletal muscle, fat tissue and brain, but it is not transported into cells via insulin-sensitive pathways (insulin regulated transporters GLUT1 and GLUT4). Instead, fructose is taken in by GLUT5. Fructose in muscles and adipose tissue is phosphorylated by hexokinase. | 6 | Carbohydrates |
Phosphor layers provide most of the light produced by fluorescent lamps, and are also used to improve the balance of light produced by metal halide lamps. Various neon signs use phosphor layers to produce different colors of light. Electroluminescent displays found, for example, in aircraft instrument panels, use a phosphor layer to produce glare-free illumination or as numeric and graphic display devices. White LED lamps consist of a blue or ultra-violet emitter with a phosphor coating that emits at longer wavelengths, giving a full spectrum of visible light. Unfocused and undeflected cathode-ray tubes have been used as stroboscope lamps since 1958. | 0 | Luminescence |
It is claimed that Vogel started his research into luminescence while he was still in his teens. This research eventually led him to publish his thesis, Luminescence in Liquids and Solids and Their Practical Application, in collaboration with University of Chicago's Dr. Peter Pringsheim in 1943.
Two years after the publication, Vogel incorporated his own company, Vogel Luminescence, in San Francisco. For the next decade the firm developed a variety of new products: fluorescent crayons, tags for insecticides, a black light inspection kit to determine the secret trackways of rodents in cellars from their urine and the psychedelic colors popular in "new age" posters. In 1957, Vogel Luminescence was sold to Ultra Violet Products and Vogel joined IBM as a full-time research scientist. He retired from IBM in 1984.
In 1977 and 1978, Vogel participated in experiments with the Markovich Tesla Electrical Power Source, referred to as MTEPS, that was built by Peter T. Markovich.
He received 32 patents for his inventions up through his tenure at IBM. Among these was the magnetic coating for the 24" hard disk drive systems still in use. His areas of expertise, besides luminescence, were phosphor technology, magnetics and liquid crystal systems.
At Vogel's February 14, 1991 funeral, IBM researcher and Sacramento, California physician Bernard McGinity, M.D. said of him, "He made his mark because of the brilliance of his mind, his prolific ideas, and his seemingly limitless creativity." | 0 | Luminescence |
A vacuum ceramic filter is designed to separate liquids from solids for dewatering of ore concentrates purposes. The device consists of a rotator, slurry tank, ceramic filter plate, distributor, discharge scraper, cleaning device, frame, agitating device, pipe system, vacuum system, automatic acid dosing system, automatic lubricating system, valve and discharge chute. The operation and construction principle of vacuum ceramic filter resemble those of a conventional disc filter, but the filter medium is replaced by a finely porous ceramic disc. The disc material is inert, has a long operational life and is resistant to almost all chemicals. Performance can be optimized by taking into account all those factors which affect the overall efficiency of the separation process. Some of the variables affecting the performance of a vacuum ceramic filter include the solid concentration, speed rotation of the disc, slurry level in the feed basin, temperature of the feed slurry, and the pressure during dewatering stages and filter cake formation. | 5 | Separation Processes |
Optical brighteners, optical brightening agents (OBAs), fluorescent brightening agents (FBAs), or fluorescent whitening agents (FWAs), are chemical compounds that absorb light in the ultraviolet and violet region (usually 340-370 nm) of the electromagnetic spectrum, and re-emit light in the blue region (typically 420-470 nm) through the phenomenon of fluorescence. These additives are often used to enhance the appearance of color of fabric and paper, causing a "whitening" effect; they make intrinsically yellow/orange materials look less so, by compensating the deficit in blue and purple light reflected by the material, with the blue and purple optical emission of the fluorophore. | 0 | Luminescence |
According to the structure and function study on the antifreeze protein from Pseudopleuronectes americanus, the antifreeze mechanism of the type-I AFP molecule was shown to be due to the binding to an ice nucleation structure in a zipper-like fashion through hydrogen bonding of the hydroxyl groups of its four Thr residues to the oxygens along the direction in ice lattice, subsequently stopping or retarding the growth of ice pyramidal planes so as to depress the freeze point.
The above mechanism can be used to elucidate the structure-function relationship of other antifreeze proteins with the following two common features:
# recurrence of a Thr residue (or any other polar amino acid residue whose side-chain can form a hydrogen bond with water) in an 11-amino-acid period along the sequence concerned, and
# a high percentage of an Ala residue component therein. | 1 | Cryobiology |
Semiconductor ultraviolet detectors are solid state, and convert an ultraviolet photon into an electric pulse. If they are transparent to visible light, then they will not be sensitive to light. | 8 | Ultraviolet Radiation |
Psychrophiles or cryophiles (adj. psychrophilic or cryophilic) are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from to . They are found in places that are permanently cold, such as the polar regions and the deep sea. They can be contrasted with thermophiles, which are organisms that thrive at unusually high temperatures, and mesophiles at intermediate temperatures. Psychrophile is Greek for cold-loving, .
Many such organisms are bacteria or archaea, but some eukaryotes such as lichens, snow algae, phytoplankton, fungi, and wingless midges, are also classified as psychrophiles. | 1 | Cryobiology |
The proteins that regulate genetics are often categorized as writers, readers, and erasers, i.e., enzymes that install epigenetic modifications, proteins that recognize these modifications, and enzymes that remove these modifications. To date, O-GlcNAc has been identified on writer and eraser enzymes. O-GlcNAc is found in multiple locations on EZH2, the catalytic methyltransferase subunit of PRC2, and is thought to stabilize EZH2 prior to PRC2 complex formation and regulate di- and tri-methyltransferase activity. All three members of the ten-eleven translocation (TET) family of dioxygenases (TET1, TET2, and TET3) are known to be modified by O-GlcNAc. O-GlcNAc has been suggested to cause nuclear export of TET3, reducing its enzymatic activity by depleting it from the nucleus. O-GlcNAcylation of HDAC1 is associated with elevated activating phosphorylation of HDAC1. | 6 | Carbohydrates |
Lactulose is useful in treating hyperammonemia (high blood ammonia), which can lead to hepatic encephalopathy. Lactulose helps trap the ammonia (NH) in the colon and bind to it. It does this by using gut flora to acidify the colon, transforming the freely diffusible ammonia into ammonium ions (), which can no longer diffuse back into the blood. It is also useful for preventing hyperammonemia caused as a side effect of administration of valproic acid. | 6 | Carbohydrates |
Vancouver-based firm, RepliCel Life Sciences Inc. has been researching the replacement of hormone-compromised hair follicle cells.
In 2013, RepliCel created a partnership with cosmetics company Shiseido, giving Shiseido an exclusive license to use its RCH-01 technology in Japan, China, South Korea, Taiwan, and the ASEAN countries. Shiseido trialed RepliCels RCH-01 in Japan and received modest results. In 2021, RepliCel initiated arbitration against Shiseido and terminated the companys license agreement. | 2 | Tissue Engineering |
In addition, it is involved in developing the Neo-GI Augment, a gastrointestinal development program; and Neo-Vessel Replacement, which targets various blood vessel applications consisting of vascular access grafts, arteriovenous, and shunts for patients with ESRD (end stage renal disease) undergoing hemodialysis treatment, as well as for vessel replacement for patients undergoing coronary or peripheral artery bypass procedures. | 2 | Tissue Engineering |
In some countries where lactulose may be obtained without a prescription, lactulose is commonly used as a food additive to improve taste and promote intestinal transit. | 6 | Carbohydrates |
3D bioprinting can be used to reconstruct tissue from various regions of the body. The precursor to the adoption of 3D printing in healthcare was a series of trials conducted by researchers at Boston Childrens Hospital. The team built replacement urinary bladders by hand for seven patients by constructing scaffolds, then layering the scaffolds with cells from the patients and allowing them to grow. The trials were a success as the patients remained in good health 7 years after implantation, which led a research fellow named Anthony Atala, MD, to search or ways to automate the process. Patients with end-stage bladder disease can now be treated by using bio-engineered bladder tissues to rebuild the damaged organ. This technology can also potentially be applied to bone, skin, cartilage and muscle tissue. Though one long-term goal of 3D bioprinting technology is to reconstruct an entire organ as well as minimize the problem of the lack of organs for transplantation. There has been little success in bioprinting of fully functional organs e.g. liver, skin, meniscus or pancreas. Unlike implantable stents, organs have complex shapes and are significantly harder to bioprint. A bioprinted heart, for example, must not only meet structural requirements, but also vascularization, mechanical load, and electrical signal propagation requirements. In 2022, the first success of a clinical trial for a 3D bioprinted transplant that is made from the patients own cells, an external ear to treat microtia, was reported.
3D bioprinting contributes to significant advances in the medical field of tissue engineering by allowing for research to be done on innovative materials called biomaterials. Some of the most notable bioengineered substances are usually stronger than the average bodily materials, including soft tissue and bone. These constituents can act as future substitutes, even improvements, for the original body materials. In addition, the Defense Threat Reduction Agency aims to print mini organs such as hearts, livers, and lungs as the potential to test new drugs more accurately and perhaps eliminate the need for testing in animals. | 2 | Tissue Engineering |
In a set of oxoacids of an element, values decrease with the oxidation state of the element. The oxoacids of chlorine illustrate this trend.
† theoretical | 4 | Acids + Bases |
Zinc sulfide phosphors are used with radioactive materials, where the phosphor was excited by the alpha- and beta-decaying isotopes, to create luminescent paint for dials of watches and instruments (radium dials). Between 1913 and 1950 radium-228 and radium-226 were used to activate a phosphor made of silver doped zinc sulfide (ZnS:Ag), which gave a greenish glow. The phosphor is not suitable to be used in layers thicker than 25 mg/cm, as the self-absorption of the light then becomes a problem. Furthermore, zinc sulfide undergoes degradation of its crystal lattice structure, leading to gradual loss of brightness significantly faster than the depletion of radium. ZnS:Ag coated spinthariscope screens were used by Ernest Rutherford in his experiments discovering atomic nucleus.
Copper doped zinc sulfide (ZnS:Cu) is the most common phosphor used and yields blue-green light. Copper and magnesium doped zinc sulfide yields yellow-orange light.
Tritium is also used as a source of radiation in various products utilizing tritium illumination. | 0 | Luminescence |
When hysteresis occurs with extensive and intensive variables, the work done on the system is the area under the hysteresis graph. | 7 | Magnetic Ordering |
There was another small group of scientists at Tufts College in Medford, Massachusetts that had become involved in research of the pinch effect. Although their work was not officially part of the Atomic Energy Commission, some of their personnel attended the Sherwood conferences. | 3 | Nuclear Fusion |
High-gradient magnetic separator is to separate magnetic and non-magnetic particles (concentrate and tails) from the feed slurry. This feed comes from intermediate thickener underflow pump through Linear Screen & Passive Matrix. Tailings go to tailing thickener & product goes to throw launder through vacuum tanks. | 5 | Separation Processes |
Of course, the composition of the material that is used as the counter electrode is extremely important to creating a working photovoltaic, as the valence and conduction energy bands must overlap with those of the redox electrolyte species to allow for efficient electron exchange.
In 2018, Jin et al. prepared ternary nickel cobalt selenide (NiCoSe) films at various stoichiometric ratios of nickel and cobalt to understand its impact on the resulting cell performance. Nickel and cobalt bimetallic alloys were known to have outstanding electron conduction and stability, so optimizing its stoichiometry would ideally produce a more efficient and stable cell performance than its singly metallic counterparts. Such is the result that Jin et al. found, as NiCoSe achieved superior power conversion efficiency (8.61%), lower charge transfer impedance, and higher electrocatalytic ability than both its platinum and binary selenide counterparts. | 8 | Ultraviolet Radiation |
4,4′-Diamino-2,2′-stilbenedisulfonic acid is the organic compound with the formula (HNCHSOH)CH. It is a white, water-soluble solid. Structurally, it is a derivative of trans-stilbene, containing amino and sulfonic acid functional groups on each of the two phenyl rings.
The compound is a popular optical brightener for use in laundry detergents.
It is produced by reduction of 4,4′-dinitro-2,2′-stilbenedisulfonic acid with iron powder. | 0 | Luminescence |
Both the formation and degradation of amylopectin is important to the metabolic processes of organisms. Amylopectin is one of the two dominant components of starch, and starch is a successful storage molecule for energy. Because of this, it is synthesized and broken down in most plants and cyanobacteria. In fact, amylopectin seems to rival glycogen, the energy storage molecule in animals, because it is able to store more glucose units and henceforth more energy.
The synthesis of amylopectin depends on the combined efforts of four different enzymes. These four different enzymes are:
# ADP glucose pyrophosphorylase (AGPase)
# soluble starch synthase (SS)
# starch branching enzyme (BE)
# starch debranching enzyme (DBE)
Amylopectin is synthesized by the linkage of α(1→4) Glycosidic bonds. The extensive branching of amylopectin (α(1→6) Glycosidic bond) is initiated by BE and this is what differentiates amylose from amylopectin. DBE is also needed during this synthesis process to regulate the distribution of these branches.
The breakdown of amylopectin has been studied in context with the breakdown of starch in animals and humans. Starch is mostly composed of amylopectin and amylose, but amylopectin has been shown to degrade more easily. The reason is most likely because amylopectin is highly branched and these branches are more available to digestive enzymes. In contrast, amylose tends to form helices and contain hydrogen bonding.
The breakdown of starch is dependent on three enzymes, among others:
# alpha, beta amylases
# phosphorylases
# starch debranching enzyme (DBE)
There are enzymes that are involved in the synthesis and degradation of amylopectin that have isoforms that display different relationships with proteins and other enzymes. For example, there are many versions of SS (Starch Synthase). Even the third isoform (SS-III) has two different versions. It is believed that SS-I and SS-II both have a role in elongating the chains of amylopectin branches. SS-IV is also thought to be responsible for the leaf-like structure of starch granule clusters. | 6 | Carbohydrates |
The demagnetizing field is the magnetic field created by the magnetic sample upon itself. The associated energy is:
where H is the demagnetizing field. This field depends on the magnetic configuration itself, and it can be found by solving:
where −∇·M is sometimes called magnetic charge density. The solution of these equations (c.f. magnetostatics) is:
where r is the vector going from the current integration point to the point where H is being calculated.
It is worth noting that the magnetic charge density can be infinite at the edges of the sample, due to M changing discontinuously from a finite value inside to zero outside of the sample. This is usually dealt with by using suitable boundary conditions on the edge of the sample.
The energy of the demagnetizing field favors magnetic configurations that minimize magnetic charges. In particular, on the edges of the sample, the magnetization tends to run parallel to the surface. In most cases it is not possible to minimize this energy term at the same time as the others. The static equilibrium then is a compromise that minimizes the total magnetic energy, although it may not minimize individually any particular term. | 7 | Magnetic Ordering |
Embryos can be either "fresh" from fertilized egg cells of the same menstrual cycle, or "frozen", that is they have been generated in a preceding cycle and undergone embryo cryopreservation, and are thawed just prior to the transfer, which is then termed "frozen embryo transfer" (FET). The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities, also between fresh versus frozen eggs used for intracytoplasmic sperm injection (ICSI). In fact, pregnancy rates are increased following FET, and perinatal outcomes are less affected, compared to embryo transfer in the same cycle as ovarian hyperstimulation was performed. The endometrium is believed to not be optimally prepared for implantation following ovarian hyperstimulation, and therefore frozen embryo transfer avails for a separate cycle to focus on optimizing the chances of successful implantation. Children born from vitrified blastocysts have significantly higher birthweight than those born from non-frozen blastocysts. When transferring a frozen-thawed oocyte, the chance of pregnancy is essentially the same whether it is transferred in a natural cycle or one with ovulation induction.
There is probably little or no difference between FET and fresh embryo transfers in terms of live birth rate and ongoing pregnancy rate and the risk of ovarian hyperstimulation syndrome may be less using the "freeze all" strategy. The risk of having a large-for-gestational-age baby and higher birth rate, in addition to maternal hypertensive disorders of pregnancy may be increased using a "freeze all" strategy. | 1 | Cryobiology |
Many known phosphorylation sites and O-GlcNAcylation sites are nearby each other or overlapping. As protein O-GlcNAcylation and phosphorylation both occur on serine and threonine residues, these post-translational modifications can regulate each other. For example, in CKIIα, S347 O-GlcNAc has been shown to antagonize T344 phosphorylation. Reciprocal inhibition, i.e., phosphorylation inhibition of O-GlcNAcylation and O-GlcNAcylation of phosphorylation, has been observed on other proteins including murine estrogen receptor β, RNA Pol II, tau, p53, CaMKIV, p65, β-catenin, and α-synuclein. Positive cooperativity has also been observed between these two post-translational modifications, i.e., phosphorylation induces O-GlcNAcylation or O-GlcNAcylation induces phosphorylation. This has been demonstrated on MeCP2 and HDAC1. In other proteins, e.g., cofilin, phosphorylation and O-GlcNAcylation appear to occur independently of each other.
In some cases, therapeutic strategies are under investigation to modulate O-GlcNAcylation to have a downstream effect on phosphorylation. For instance, elevating tau O-GlcNAcylation may offer therapeutic benefit by inhibiting pathological tau hyperphosphorylation.
Besides phosphorylation, O-GlcNAc has been found to influence other post-translational modifications such as lysine acetylation and monoubiquitination. | 6 | Carbohydrates |
Fusion constructs of a nanobody and TPR-truncated OGT allow for proximity-induced protein-specific O-GlcNAcylation in cells. The nanobody may be directed towards protein tags, e.g., GFP, that are fused to the target protein, or the nanobody may be directed towards endogenous proteins. For example, a nanobody recognizing a C-terminal EPEA sequence can direct OGT enzymatic activity to α-synuclein. | 6 | Carbohydrates |
Vat level and drum speed are the two basic operating parameters for any rotary vacuum drum filter. These parameters are adjusted dependently to each other to optimize the filtration performance.
Valve level determines the proportion filter cycle in the filter. The filter cycle consist of the filter drum rotation, release of cake formation from slurry and the drying period for the cake formation shown in figure 1. By default, operate the vat at its maximum level to maximise the rate of filtration. Reduce vat level if discharged solid is in the form of thin and slimy cake or if the discharged solid is very thick.
Decrease in the vat level eventually leads to a decrease in the portion of the drum being submerge under the slurry, more surface exposure for the cake dying surface hence, larger cake formation to dry time ratio. This result in less moisture content of formed solid and lessen the thickness of the form solid. In addition to operating at lower vat level, the flow rate per drum revolution decreases and ultimately thinner cake formation occurs. In the case of pre coat discharge the filter aid efficiency increases.
Drum speed is the driving factor for the filter output and its units is in the form of minutes per drum revolution. At steady operating conditions, adjusting the drum speed gives a proportional relationship with the filter throughput as shown as in figure 2. | 5 | Separation Processes |
The International Thermonuclear Experimental Reactor (ITER) coalition forms, involving EURATOM, Japan, the Soviet Union and United States and kicks off the conceptual design process. | 3 | Nuclear Fusion |
In aerodynamics, hysteresis can be observed when decreasing the angle of attack of a wing after stall, regarding the lift and drag coefficients. The angle of attack at which the flow on top of the wing reattaches is generally lower than the angle of attack at which the flow separates during the increase of the angle of attack. | 7 | Magnetic Ordering |
Graphene membranes are meant to take advantage of their thinness to increase efficiency. Graphene is a singular layer of carbon atoms, so it is about 1000 times thinner than existing membranes. Graphene membranes are around 100 nm thick while current membranes are about 100 µm. Many researchers were concerned with the durability of graphene and if it would be able to handle RO pressures. New research finds that depending on the substrate (a supporting layer that does no filtration and only provides structural support), graphene membranes can withstand 57MPa of pressure which is about 10 times the typical pressures for seawater RO.
Batch RO may offer increased energy efficiency, more durable equipment and higher salinity limits.
The conventional approach claimed that molecules cross the membrane individually. A research team devised a "solution-friction" theory, claiming that molecules in groups through transient pores. Characterizing that process could guide membrane development. The accepted theory is that individual water molecules diffuse through the membrane, termed the "solution-diffusion" model. | 5 | Separation Processes |
Apoptosis, a form of controlled cell death, has been suggested to be regulated by O-GlcNAc. In various cancers, elevated O-GlcNAc levels have been reported to suppress apoptosis. Caspase-3, caspase-8, and caspase-9 have been reported to be modified by O-GlcNAc. Caspase-8 is modified near its cleavage/activation sites; O-GlcNAc modification may block caspase-8 cleavage and activation by steric hindrance. Pharmacological lowering of O-GlcNAc with 5S-GlcNAc accelerated caspase activation while pharmacological raising of O-GlcNAc with thiamet-G inhibited caspase activation. | 6 | Carbohydrates |
Implantation of any foreign device or material through the means of surgery results in at least some degree of tissue trauma. Therefore, especially when removing a native heart valve either partially or completely, the tissue trauma will trigger a cascade of inflammatory responses and elicit acute inflammation. During the initial phase of acute inflammation, vasodilation occurs to increase blood flow to the wound site along with the release of growth factors, cytokines, and other immune cells. Furthermore, cells release reactive oxygen species and cytokines, which cause secondary damage to surrounding tissue. These chemical factors then proceed to promote the recruitment of other immune responsive cells such as monocytes or white blood cells, which help foster the formation of a blood clot and protein-rich matrix. | 2 | Tissue Engineering |
Magnetic materials with strong spin-orbit interaction, such as: LaFeAsO, PrFeP, YbRuGe, UO, NpO, CeLaB, URuSi and many other compounds, are found to have magnetic ordering constituted by high rank multipoles, e.g. quadruple, octople, etc. Due to the strong spin-orbit coupling, multipoles are automatically introduced to the systems when the total angular momentum quantum number J is larger than 1/2. If those multipoles are coupled by some exchange mechanisms, those multipoles could tend to have some ordering as conventional spin 1/2 Heisenberg problem. Except the multipolar ordering, many hidden order phenomena are believed closely related to the multipolar interactions | 7 | Magnetic Ordering |
An important parameter in wet scrubbing systems is the rate of liquid flow. It is common in wet scrubber terminology to express the liquid flow as a function of the gas flow rate that is being treated. This is commonly called the liquid-to-gas ratio (L/G ratio) and uses the units of gallons per 1,000 actual cubic feet or litres per cubic metre (L/m).
Expressing the amount of liquid used as a ratio enables systems of different sizes to be readily compared.
For particulate removal, the liquid-to-gas ratio is a function of the mechanical design of the system; while for gas absorption this ratio gives an indication of the difficulty of removing a pollutant. Most wet scrubbers used for particulate control operate with liquid-to-gas ratios in the range of 4 to 20 gallons per 1,000 actual cubic foot (0.5 to 3 litres per actual cubic metre).
Depending on scrubber design, a minimum volume of liquid is required to "wet" the scrubber internals and create sufficient collection targets. After a certain optimum point, adding excess liquid to a particulate wet scrubber does not increase efficiency and in fact, could be counter-productive by causing excessive pressure loss. Liquid-to-gas ratios for gas absorption are often higher, in the range of 20 to 40 gallons per 1,000 actual cubic foot (3 to 6 litres per actual cubic metre).
L/G ratio illustrates a number of points about the choice of wet scrubbers used for gas absorption. For example, because flue-gas desulfurization systems must deal with heavy particulate loadings, open, simple designs (such as venturi, spray chamber and moving bed) are used.
Also, the liquid-to-gas ratio for the absorption process is higher than for particle removal and gas velocities are kept low to enhance the absorption process.
Solubility is a very important factor affecting the amount of a pollutant that can be absorbed. Solubility governs the amount of liquid required (liquid-to-gas ratio) and the necessary contact time. More soluble gases require less liquid. Also, more soluble gases will be absorbed faster. | 5 | Separation Processes |
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. | 8 | Ultraviolet Radiation |
Droplet-based microfluidics can be used to generate microparticles with repeatable size.
* manipulation of alginate solution to allow microcapsules to be created | 2 | Tissue Engineering |
Distillation is a process in which we separate components of different vapour pressure. One fraction leaves overhead and is condensed to distillate and the other is the bottom product. The bottom product is mostly liquid while the overhead fraction can be vapour or an aerosol.
This method requires the components to have different volatility to be separated.
The column consists of three sections: a stripping section, a rectification section, and a feed section.
For rectification and stripping a countercurrent liquid phase must flow through the column, so that liquid and vapour can contact each other on each stage.
The distillation column is fed with a mixture containing the mole fraction xf of the desired compound. The overhead mixture is a gas or an aerosol which contains the mole fraction xD of the desired compound and the bottom product contains a mixture with the fraction xB of the desired compound.
An overhead condenser is a heat exchange equipment used for condensing the mixture leaving the top of the column. Either cooling water or air is used as a cooling agent.
An overhead accumulator is a horizontal pressure vessel containing the condensed mixture.
Pumps can be used to control the reflux to the column.
A Reboiler produces the vapour stream in the distillation column. It can be used internally and externally. | 5 | Separation Processes |
Biodegradable additives may be added to polymers to accelerate their degradation. In the case of photo-oxidation OXO-biodegradation additives are used. These are transition metal salts such as iron (Fe), manganese (Mn), and cobalt (Co). Fe complexes increase the rate of photooxidation by promoting the homolysis of hydroperoxides via Fenton reactions.
The use of such additives has been controversial due to concerns that treated plastics do not fully biodegrade and instead result in the accelerated formation of microplastics. Oxo-plastics would be difficult to distinguish from untreated plastic but their inclusion during plastic recycling can create a destabilised product with fewer potential uses, potentially jeopardising the business case for recycling any plastic. OXO-biodegradation additives were banned in the EU in 2019 | 8 | Ultraviolet Radiation |
Salt compounds dissociate in aqueous solutions. This property is exploited in the process of salting out. When the salt concentration is increased, some of the water molecules are attracted by the salt ions, which decreases the number of water molecules available to interact with the charged part of the protein.
There are hydrophobic amino acids and hydrophilic amino acids in protein molecules.
After protein folding in aqueous solution, hydrophobic amino acids usually form protected hydrophobic areas while hydrophilic amino acids interact with the molecules of solvation and allow proteins to form hydrogen bonds with the surrounding water molecules. If enough of the protein surface is hydrophilic, the protein can be dissolved in water.
When salt is added to the solution, there is more frequent interaction between solvent molecules and salt ions. As a result, the protein and salt ions compete to interact with the solvent molecules with the result that there are fewer solvent molecules available for interaction with the protein molecules than before. The protein–protein interactions thus become stronger than the solvent–solute interactions and the protein molecules associate by forming hydrophobic interactions with each other. After dissociation in a given solvent, the negatively charged atoms from a chosen salt begin to compete for interactions with positively charged molecules present in the solution. Similarly, the positively charged cations compete for interactions with the negatively charged molecules of the solvent. This process is known as salting out.
Soaps are easily precipitated by concentrated salt solution, the metal ion in the salt reacts with the fatty acids forming back the soap and glycerin (glycerol). To separate glycerin from the soap, the pasty boiling mass is treated with brine (NaCl solution). Contents of the kettle salt out (separate) into an upper layer that is a curdy mass of impure soap and a lower layer that consists of an aqueous salt solution with the glycerin dissolved in it. The slightly alkaline salt solution, termed spent lye, is extracted from the bottom of the pan or kettle and may be subsequently treated for glycerin recovery. | 5 | Separation Processes |
Amasa Stone Bishop (1921 – May 21, 1997) was an American nuclear physicist specializing in fusion physics. He received his B.S. in physics from the California Institute of Technology in 1943. From 1943 to 1946 he was a member of the staff of Radiation Laboratory at the Massachusetts Institute of Technology, where he was involved with radar research and development. Later, he became a staff member of the University of California at Berkeley from 1946 to 1950. Specializing in high energy particle work, he earned his Ph.D. in physics in 1950.
After attaining his Ph.D., Amasa spent three years in Switzerland, acting as research associate at the Federal Institute of Technology in Zürich, and later at the University of Zürich. In 1953 Amasa joined the research division of the Atomic Energy Commission (AEC) in Washington and became the director of the American program to develop controlled fusion, also known as Project Sherwood. He was later presented the AEC Outstanding Service Award for his work. After leaving this position in 1956, Amasa published a book on behalf of the AEC discussing the various attempts at harnessing fusion under Project Sherwood. The book, "Project Sherwood: The U.S. Program in Controlled Fusion", was published in 1958.
After 1956 Amasa also served as the AEC's European scientific representative, based in Paris. He was also an assistant delegate to the European atomic energy agency, Euratom, in Brussels. Later he spent several years in Princeton, New Jersey, and was in charge of the fusion program in Washington.
In 1970 Amasa joined the United Nations in Europe as director of environment of the United Nations Economic Commission for Europe. During this position, he worked with scientists and diplomats to create solutions for various environmental problems. He left this position to retire in 1980. Amasa died on May 21, 1997, of pneumonia related to Alzheimer's disease at the Clinique de Genolier in Genolier, Switzerland.
Bishop was the great-grandson of Industrialist Amasa Stone. | 3 | Nuclear Fusion |
A magnetic particle with cubic anisotropy has three or four easy axes, depending on the anisotropy parameters. The energy has the form
If the easy axes are the and axes. If there are four easy axes characterized by . | 7 | Magnetic Ordering |
Sonoluminescence is the emission of light from imploding bubbles in a liquid when excited by sound.
Sonoluminescence was first discovered in 1934 at the University of Cologne. It occurs when a sound wave of sufficient intensity induces a gaseous cavity within a liquid to collapse quickly, emitting a burst of light. The phenomenon can be observed in stable single-bubble sonoluminescence (SBSL) and multi-bubble sonoluminescence (MBSL). In 1960, Peter Jarman proposed that sonoluminescence is thermal in origin and might arise from microshocks within collapsing cavities. Later experiments revealed that the temperature inside the bubble during SBSL could reach up to . The exact mechanism behind sonoluminescence remains unknown, with various hypotheses including hotspot, bremsstrahlung, and collision-induced radiation. Some researchers have even speculated that temperatures in sonoluminescing systems could reach millions of kelvins, potentially causing thermonuclear fusion; this idea, however, has been met with skepticism by other researchers. The phenomenon has also been observed in nature, with the pistol shrimp being the first known instance of an animal producing light through sonoluminescence. | 0 | Luminescence |
Drop-based bioprinting makes cellular developments utilizing droplets of an assigned material, which has oftentimes been combined with a cell line. Cells themselves can also be deposited in this manner with or without polymer. When printing polymer scaffolds using these methods, each drop starts to polymerize upon contact with the substrate surface and merge into a larger structure as droplets start to coalesce. Polymerization can happen through a variety of methods depending on the polymer used. For instance, alginate polymerization is started by calcium ions in the substrate, which diffuse into the liquified bioink and permit for the arrangement of a strong gel. Drop-based bioprinting is commonly utilized due to its productive speed. However, this may make it less appropriate for more complicated organ structures. | 2 | Tissue Engineering |
A. Hari Reddi (born October 20, 1942) is a Distinguished Professor and holder of the Lawrence J. Ellison Endowed Chair in Musculoskeletal Molecular Biology at the University of California, Davis. He was previously the Virginia M. and William A. Percy Chair and Professor in Orthopaedic Surgery, Professor of Biological Chemistry, and Professor of Oncology at the Johns Hopkins University School of Medicine. Professor Reddi's research played an indispensable role in the identification, isolation and purification of bone morphogenetic proteins (BMPs) that are involved in bone formation and repair. The molecular mechanism of bone induction studied by Professor Reddi led to the conceptual advance in tissue engineering that morphogens in the form of metabologens bound to an insoluble extracellular matrix scaffolding act in collaboration to stimulate stem cells to form cartilage and bone. The Reddi laboratory has also made important discoveries unraveling the role of the extracellular matrix in bone and cartilage tissue regeneration and repair. | 2 | Tissue Engineering |
Organoids provide an opportunity to create cellular models of human disease, which can be studied in the laboratory to better understand the causes of disease and identify possible treatments. The power of organoids in this regard was first shown for a genetic form of microcephaly, where patient cells were used to make cerebral organoids, which were smaller and showed abnormalities in early generation of neurons. In another example, the genome editing system called CRISPR was applied to human pluripotent stem cells to introduce targeted mutations in genes relevant to two different kidney diseases, polycystic kidney disease and focal segmental glomerulosclerosis. These CRISPR-modified pluripotent stem cells were subsequently grown into human kidney organoids, which exhibited disease-specific phenotypes. Kidney organoids from stem cells with polycystic kidney disease mutations formed large, translucent cyst structures from kidney tubules. When cultured in the absence of adherent cues (in suspension), these cysts reached sizes of 1 cm in diameter over several months. Kidney organoids with mutations in a gene linked to focal segmental glomerulosclerosis developed junctional defects between podocytes, the filtering cells affected in that disease. Importantly, these disease phenotypes were absent in control organoids of identical genetic background, but lacking the CRISPR mutations. Comparison of these organoid phenotypes to diseased tissues from mice and humans suggested similarities to defects in early development.
As first developed by Takahashi and Yamanaka in 2007, induced pluripotent stem cells (iPSC) can also be reprogrammed from patient skin fibroblasts. These stem cells carry the exact genetic background of the patient including any genetic mutations which might contribute to the development of human disease. Differentiation of these cells into kidney organoids has been performed from patients with Lowe Syndrome due to ORCL1 mutations. This report compared kidney organoids differentiated from patient iPSC to unrelated control iPSC and demonstrated an inability of patient kidney cells to mobilise transcription factor SIX2 from the golgi complex. Because SIX2 is a well characterised marker of nephron progenitor cells in the cap mesenchyme, the authors concluded that renal disease frequently seen in Lowe Syndrome (global failure of proximal tubule reabsorption or renal Fanconi syndrome) could be related to alteration in nephron patterning arising from nephron progenitor cells lacking this important SIX2 gene expression.
Other studies have used CRISPR gene editing to correct the patients mutation in the patient iPSC cells to create an isogenic control, which can be performed simultaneously with iPSC reprogramming. Comparison of a patient iPSC derived organoid against an isogenic control is the current gold standard in the field as it permits isolation of the mutation of interest as the only variable within the experimental model. In one such report, kidney organoids derived from iPSC of a patient with Mainzer-Saldino Syndrome due to compound heterozygous mutations in IFT140 were compared to an isogenic control organoid in which an IFT140' variant giving rise to a non-viable mRNA transcript was corrected by CRISPR. Patient kidney organoids demonstrated abnormal ciliary morphology consistent with existing animal models which was rescued to wild type morphology in the gene corrected organoids. Comparative transcriptional profiling of epithelial cells purified from patient and control organoids highlighted pathways involved in cell polarity, cell-cell junctions and dynein motor assembly, some of which had been implicated for other genotypes within the phenotypic family of renal ciliopathies. Another report utilising an isogenic control demonstrated abnormal nephrin localisation in the glomeruli of kidney organoids generated from a patient with congenital nephrotic syndrome.
Things such as epithelial metabolism can also be modelled. | 2 | Tissue Engineering |
* Sodium: 15 mmol/L
* Potassium: 9 mmol/L
* Magnesium: 4 mmol/L
* Calcium: 0.015 mmol/L
* Ketoglutarate/glutamic acid: 1 mmol/L
* Histidine: 198 mmol/L
* Mannitol: 30 mmol/L
* Tryptophan: 2 mmol/L | 1 | Cryobiology |
Princeton's conversion of the Model C stellarator to a tokamak produced results matching the Soviets. With an apparent solution to the magnetic bottle problem in-hand, plans begin for a larger machine to test scaling and methods to heat the plasma.
In 1972, John Nuckolls outlined the idea of fusion ignition, a fusion chain reaction. Hot helium made during fusion reheats the fuel and starts more reactions. Nuckolls's paper started a major development effort. LLNL built laser systems including Argus, Cyclops, Janus, the neodymium-doped glass (Nd:glass) laser Long Path, Shiva laser, and the 10 beam Nova in 1984. Nova would ultimately produce 120 kilojoules of infrared light during a nanosecond pulse.
The UK built the Central Laser Facility in 1976.
The "advanced tokamak" concept emerged, which included non-circular plasma, internal diverters and limiters, superconducting magnets, and operation in the so-called "H-mode" island of increased stability. Two other designs became prominent; the compact tokamak sited the magnets on the inside of the vacuum chamber, and the spherical tokamak with as small a cross section as possible.
In 1974 J.B. Taylor re-visited ZETA and noticed that after an experimental run ended, the plasma entered a short period of stability. This led to the reversed field pinch concept. On May 1, 1974, the KMS fusion company (founded by Kip Siegel) achieved the world's first laser induced fusion in a deuterium-tritium pellet.
The Princeton Large Torus (PLT), the follow-on to the Symmetrical Tokamak, surpassed the best Soviet machines and set temperature records that were above what was needed for a commercial reactor. Soon after it received funding with the target of breakeven.
In the mid-1970s, Project PACER, carried out at LANL explored the possibility of exploding small hydrogen bombs (fusion bombs) inside an underground cavity. As an energy source, the system was the only system that could work using the technology of the time. It required a large, continuous supply of nuclear bombs, however, with questionable economics.
In 1976, the two beam Argus laser became operational at LLNL. In 1977, the 20 beam Shiva laser there was completed, capable of delivering 10.2 kilojoules of infrared energy on target. At a price of $25 million and a size approaching that of a football field, Shiva was the first megalaser.
At a 1977 workshop at the Claremont Hotel in Berkeley Dr. C. Martin Stickley, then Director of the Energy Research and Development Agency ’s Office of Inertial Fusion, claimed that "no showstoppers" lay on the road to fusion energy.
The DOE selected a Princeton design Tokamak Fusion Test Reactor (TFTR) and the challenge of running on deuterium-tritium fuel.
The 20 beam Shiva laser at LLNL became capable of delivering 10.2 kilojoules of infrared energy on target. Costing $25 million and nearly covering a football field, Shiva was the first "megalaser" at LLNL. | 3 | Nuclear Fusion |
Psychrotrophic microbes are able to grow at temperatures below , but have better growth rates at higher temperatures. Psychrotrophic bacteria and fungi are able to grow at refrigeration temperatures, and can be responsible for food spoilage and as foodborne pathogens such as Yersinia. They provide an estimation of the product's shelf life, but also they can be found in soils, in surface and deep sea waters, in Antarctic ecosystems, and in foods.
Psychrotrophic bacteria are of particular concern to the dairy industry. Most are killed by pasteurization; however, they can be present in milk as post-pasteurization contaminants due to less than adequate sanitation practices. According to the Food Science Department at Cornell University, psychrotrophs are bacteria capable of growth at temperatures at or less than . At freezing temperatures, growth of psychrotrophic bacteria becomes negligible or virtually stops.
All three subunits of the RecBCD enzyme are essential for physiological activities of the enzyme in the Antarctic Pseudomonas syringae, namely, repairing of DNA damage and supporting the growth at low temperature. The RecBCD enzymes are exchangeable between the psychrophilic P. syringae and the mesophilic E. coli when provided with the entire protein complex from same species. However, the RecBC proteins (RecBCPs and RecBCEc) of the two bacteria are not equivalent; the RecBCEc is proficient in DNA recombination and repair, and supports the growth of P. syringae at low temperature, while RecBCPs is insufficient for these functions. Finally, both helicase and nuclease activity of the RecBCDPs are although important for DNA repair and growth of P. syringae at low temperature, the RecB-nuclease activity is not essential in vivo. | 1 | Cryobiology |
Many syntheses have been developed. One popular route entails reduction of benzoin using zinc amalgam.
:CH–CH(OH)–C(=O)–CH trans-CH–CH=CH–CH
Both isomers of stilbene can be produced by decarboxylation of α-phenylcinnamic acid, trans-stilbene being produced from the of the acid.
Richard F. Heck and Tsutomu Mizoroki independently reported the synthesis of trans-stilbene by coupling of iodobenzene and styrene using a palladium(II) catalyst, in what is now known as the Mizoroki-Heck reaction. The Mizoroki approach produced the higher yield.
Stilbene undergoes reactions typical of alkenes. Trans-stilbene undergoes epoxidation with peroxymonophosphoric acid, HPO, producing a 74% yield of trans-stilbene oxide in dioxane. The epoxide product formed is a racemic mixture of the two enantiomers of 1,2-diphenyloxirane. The achiral meso compound (1R,2S)-1,2-diphenyloxirane arises from cis-stilbene, though peroxide epoxidations of the cis-isomer produce both cis- and trans-epoxide products. For example, using tert-butyl hydroperoxide, oxidation of cis-stilbene produces 0.8% cis-stilbene oxide, 13.5% trans-stilbene oxide, and 6.1% benzaldehyde. Enantiopure stilbene oxide has been prepared by Nobel laureate Karl Barry Sharpless.
Stilbene can be cleanly oxidised to benzaldehyde by ozonolysis or Lemieux–Johnson oxidation, and stronger oxidants such as acidified potassium permanganate will produce benzoic acid. Vicinal diols can be produced via the Upjohn dihydroxylation or enantioselectively using Sharpless asymmetric dihydroxylation with enantiomeric excesses as high as 100%.
Bromination of trans-stilbene produces predominantly meso-1,2-dibromo-1,2-diphenylethane (sometimes called meso-stilbene dibromide), in line with a mechanism involving a cyclic bromonium ion intermediate of a typical electrophilic bromine addition reaction; cis-stilbene yields a racemic mixture of the two enantiomers of 1,2-dibromo-1,2-diphenylethane in a non-polar solvent such as carbon tetrachloride, but the extent of production of the meso compound increases with solvent polarity, with a yield of 90% in nitromethane. The formation of small quantities of the two enantiomers of stilbene dibromide from the trans-isomer suggests that the bromonium ion intermediate exists in chemical equilibrium with a carbocation intermediate PhCHBr–C(H)Ph with a vacant p orbital vulnerable to nucleophilic attack from either face. The addition of bromide or tribromide salts restores much of the stereospecificity even in solvents with a dielectric constant above 35.
Upon UV irradiation it converts to cis-stilbene, a classic example of a photochemical reaction involving trans-cis isomerization, and can undergo further reaction to form phenanthrene. | 0 | Luminescence |