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Certain skin conditions, including keratosis, psoriasis, eczema and acne, may be treated with UVB light therapy, including by using tanning beds in commercial salons. Using tanning beds allows patients to access UV exposure when dermatologist-provided phototherapy is not available. A systematic review of studies, published in Dermatology and Therapy in 2015, noted that moderate sunlight is a treatment recommended by the American National Psoriasis Foundation, and suggested that clinicians consider UV phototherapy and tanning beds as a source of that therapy.
When UV light therapy is used in combination with psoralen, an oral or topical medication, the combined therapy is referred to as PUVA. A concern with the use of commercial tanning is that beds that primarily emit UVA may not treat psoriasis effectively. One study found that plaque psoriasis is responsive to erythemogenic doses of either UVA or UVB. It does require more energy to reach erythemogenic dosing with UVA. | 8 | Ultraviolet Radiation |
Method suitable for effective testing of magnetoelastic effect in magnetic materials should fulfill the following requirements:
* magnetic circuit of the tested sample should be closed. Open magnetic circuit causes demagnetization, which reduces magnetoelastic effect and complicates its analysis.
* distribution of stresses should be uniform. Value and direction of stresses should be known.
* there should be the possibility of making the magnetizing and sensing windings on the sample - necessary to measure magnetic hysteresis loop under mechanical stresses.
Following testing methods were developed:
* tensile stresses applied to the strip of magnetic material in the shape of a ribbon. Disadvantage: open magnetic circuit of the tested sample.
* tensile or compressive stresses applied to the frame-shaped sample. Disadvantage: only bulk materials may be tested. No stresses in the joints of sample columns.
* compressive stresses applied to the ring core in the sideways direction. Disadvantage: non-uniform stresses distribution in the core .
* tensile or compressive stresses applied axially to the ring sample. Disadvantage: stresses are perpendicular to the magnetizing field. | 7 | Magnetic Ordering |
The ARC fusion reactor (affordable, robust, compact) is a design for a compact fusion reactor developed by the Massachusetts Institute of Technology (MIT) Plasma Science and Fusion Center (PSFC). ARC aims to achieve an engineering breakeven of three (to produce three times the electricity required to operate the machine). The key technical innovation is to use high-temperature superconducting magnets in place of ITER's low-temperature superconducting magnets. The proposed device would be about half the diameter of the ITER reactor and cheaper to build.
The ARC has a conventional advanced tokamak layout. ARC uses rare-earth barium copper oxide (REBCO) high-temperature superconductor magnets in place of copper wiring or conventional low-temperature superconductors. These magnets can be run at much higher field strengths, 23 T, roughly doubling the magnetic field on the plasma axis. The confinement time for a particle in plasma varies with the square of the linear size, and power density varies with the fourth power of the magnetic field, so doubling the magnetic field offers the performance of a machine 4 times larger. The smaller size reduces construction costs, although this is offset to some degree by the expense of the REBCO magnets.
The use of REBCO may allow the magnet windings to be flexible when the machine is not operational. This would allow them to be "folded open" to allow access to the interior of the machine. This would greatly lower maintenance costs, eliminating the need to perform maintenance through small access ports using remote manipulators. If realized, this could improve the reactor's capacity factor, an important metric in power generation costs.
The first machine planned to come from the project is a scaled-down demonstrator named SPARC (as Soon as Possible ARC). It is to be built by Commonwealth Fusion Systems, with backing led by Eni, Breakthrough Energy Ventures, Khosla Ventures, Temasek, and Equinor. | 3 | Nuclear Fusion |
In spite of the second law of thermodynamics, crystallization of pure liquids usually begins at a lower temperature than the melting point, due to high activation energy of homogeneous nucleation. The creation of a nucleus implies the formation of an interface at the boundaries of the new phase. Some energy is expended to form this interface, based on the surface energy of each phase. If a hypothetical nucleus is too small, the energy that would be released by forming its volume is not enough to create its surface, and nucleation does not proceed. Freezing does not start until the temperature is low enough to provide enough energy to form stable nuclei. In presence of irregularities on the surface of the containing vessel, solid or gaseous impurities, pre-formed solid crystals, or other nucleators, heterogeneous nucleation may occur, where some energy is released by the partial destruction of the previous interface, raising the supercooling point to be near or equal to the melting point. The melting point of water at 1 atmosphere of pressure is very close to 0 °C (32 °F, 273.15 K), and in the presence of nucleating substances the freezing point of water is close to the melting point, but in the absence of nucleators water can supercool to before freezing. Under high pressure (2,000 atmospheres) water will supercool to as low as before freezing. | 1 | Cryobiology |
Carbohydrates are polyhydroxy aldehydes, ketones, alcohols, acids, their simple derivatives and their polymers having linkages of the acetal type. They may be classified according to their degree of polymerization, and may be divided initially into three principal groups, namely sugars, oligosaccharides and polysaccharides. | 6 | Carbohydrates |
In its properties hydrazoic acid shows some analogy to the halogen acids, since it forms poorly soluble (in water) lead, silver and mercury(I) salts. The metallic salts all crystallize in the anhydrous form and decompose on heating, leaving a residue of the pure metal. It is a weak acid (pK = 4.75.) Its heavy metal salts are explosive and readily interact with the alkyl iodides. Azides of heavier alkali metals (excluding lithium) or alkaline earth metals are not explosive, but decompose in a more controlled way upon heating, releasing spectroscopically-pure gas. Solutions of hydrazoic acid dissolve many metals (e.g. zinc, iron) with liberation of hydrogen and formation of salts, which are called azides (formerly also called azoimides or hydrazoates).
Hydrazoic acid may react with carbonyl derivatives, including aldehydes, ketones, and carboxylic acids, to give an amine or amide, with expulsion of nitrogen. This is called Schmidt reaction or Schmidt rearrangement.
Dissolution in the strongest acids produces explosive salts containing the aminodiazonium ion , for example:
The ion is isoelectronic to diazomethane .
The decomposition of hydrazoic acid, triggered by shock, friction, spark, etc. produces nitrogen and hydrogen:
Hydrazoic acid undergoes unimolecular decomposition at sufficient energy:
The lowest energy pathway produces NH in the triplet state, making it a spin-forbidden reaction. This is one of the few reactions whose rate has been determined for specific amounts of vibrational energy in the ground electronic state, by laser photodissociation studies. In addition, these unimolecular rates have been analyzed theoretically, and the experimental and calculated rates are in reasonable agreement. | 4 | Acids + Bases |
Orthopaedic implants help alleviate issues with the bones and joints of the body. They are used to treat bone fractures, osteoarthritis, scoliosis, spinal stenosis, and chronic pain. Examples include a wide variety of pins, rods, screws, and plates used to anchor fractured bones while they heal.
Metallic glasses based on magnesium with zinc and calcium addition are tested as the potential metallic biomaterials for biodegradable medical implants.
Patients with orthopaedic implants sometimes need to be put under magnetic resonance imaging (MRI) machine for detailed musculoskeletal study. Therefore, concerns have been raised regarding the loosening and migration of implant, heating of the implant metal which could cause thermal damage to surrounding tissues, and distortion of the MRI scan that affects the imaging results. A study of orthopaedic implants in 2005 has shown that majority of the orthopaedic implants does not react with magnetic fields under the 1.0 Tesla MRI scanning machine with the exception of external fixator clamps. However, at 7.0 Tesla, several orthopaedic implants would show significant interaction with the MRI magnetic fields, such as heel and fibular implant. | 2 | Tissue Engineering |
The fusion process alone currently does not achieve sufficient gain (power output over power input) to be viable as a power source. By using the excess neutrons from the fusion reaction to in turn cause a high-yield fission reaction (close to 100%) in the surrounding subcritical fissionable blanket, the net yield from the hybrid fusion–fission process can provide a targeted gain of 100 to 300 times the input energy (an increase by a factor of three or four over fusion alone). Even allowing for high inefficiencies on the input side (i.e. low laser efficiency in ICF and Bremsstrahlung losses in Tokamak designs), this can still yield sufficient heat output for economical electric power generation. This can be seen as a shortcut to viable fusion power until more efficient pure fusion technologies can be developed, or as an end in itself to generate power, and also consume existing stockpiles of nuclear fissionables and waste products.
In the LIFE project at the Lawrence Livermore National Laboratory LLNL, using technology developed at the National Ignition Facility, the goal is to use fuel pellets of deuterium and tritium surrounded by a fissionable blanket to produce energy sufficiently greater than the input (laser) energy for electrical power generation. The principle involved is to induce inertial confinement fusion (ICF) in the fuel pellet which acts as a highly concentrated point source of neutrons which in turn converts and fissions the outer fissionable blanket. In parallel with the ICF approach, the University of Texas at Austin is developing a system based on the tokamak fusion reactor, optimising for nuclear waste disposal versus power generation. The principles behind using either ICF or tokamak reactors as a neutron source are essentially the same (the primary difference being that ICF is essentially a point-source of neutrons while Tokamaks are more diffuse toroidal sources). | 3 | Nuclear Fusion |
Sedimentation in potable water treatment generally follows a step of chemical coagulation and flocculation, which allows grouping particles together into flocs of a bigger size. This increases the settling speed of suspended solids and allows settling colloids. | 5 | Separation Processes |
The use of an ideal high quality biomaterial with the inherent properties of biocompatibility is the most crucial factor that governs the long term efficiency of this technology. An ideal biomaterial for cell encapsulation should be one that is totally biocompatible, does not trigger an immune response in the host and does not interfere with cell homeostasis so as to ensure high cell viability. However, one major limitation has been the inability to reproduce the different biomaterials and the requirements to obtain a better understanding of the chemistry and biofunctionality of the biomaterials and the microencapsulation system. Several studies demonstrate that surface modification of these cell containing microparticles allows control over the growth and cellular differentiation. of the encapsulated cells.
One study proposed the use of zeta potential which measures the electric charge of the microcapsule as a means to predict the interfacial reaction between microcapsule and the surrounding tissue and in turn the biocompatibility of the delivery system. | 2 | Tissue Engineering |
Hypothermia has been applied therapeutically since antiquity. The Greek physician Hippocrates, the namesake of the Hippocratic Oath, advocated the packing of wounded soldiers in snow and ice. Napoleonic surgeon Baron Dominique Jean Larrey recorded that officers who were kept closer to the fire survived less often than the minimally pampered infantrymen. In modern times, the first medical article concerning hypothermia was published in 1945. This study focused on the effects of hypothermia on patients with severe head injury. In the 1950s, hypothermia received its first medical application, being used in intracerebral aneurysm surgery to create a bloodless field. Most of the early research focused on the applications of deep hypothermia, defined as a body temperature of . Such an extreme drop in body temperature brings with it a whole host of side effects, which made the use of deep hypothermia impractical in most clinical situations.
This period also saw sporadic investigation of more mild forms of hypothermia, with mild hypothermia being defined as a body temperature of . In the 1950s, Doctor Rosomoff demonstrated in dogs the positive effects of mild hypothermia after brain ischemia and traumatic brain injury. In the 1980s further animal studies indicated the ability of mild hypothermia to act as a general neuroprotectant following a blockage of blood flow to the brain. This animal data was supported by two landmark human studies that were published simultaneously in 2002 by the New England Journal of Medicine. Both studies, one occurring in Europe and the other in Australia, demonstrated the positive effects of mild hypothermia applied following cardiac arrest. Responding to this research, in 2003 the American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR) endorsed the use of targeted temperature management following cardiac arrest. Currently, a growing percentage of hospitals around the world incorporate the AHA/ILCOR guidelines and include hypothermic therapies in their standard package of care for patients with cardiac arrest. Some researchers go so far as to contend that hypothermia represents a better neuroprotectant following a blockage of blood to the brain than any known drug. Over this same period a particularly successful research effort showed that hypothermia is a highly effective treatment when applied to newborn infants following birth asphyxia. Meta-analysis of a number of large randomised controlled trials showed that hypothermia for 72 hours started within 6 hours of birth significantly increased the chance of survival without brain damage. | 1 | Cryobiology |
The columns are made of stainless steel. Conical vanes are attached alternately to the wall of the column and to a central rotating shaft. The product is poured in at the top under vacuum, and steam is pumped into the column from below. The vanes provide a large surface area over which volatile compounds can evaporate into the steam, and the rotation ensures a thin layer of the product is constantly moved over the moving cone. It typically takes 20 seconds for the liquid to move through the column, and industrial columns might process . The temperature and pressure can be adjusted depending on the compounds targeted. | 5 | Separation Processes |
The idea of hysteresis is used extensively in the area of labor economics, specifically with reference to the unemployment rate. According to theories based on hysteresis, severe economic downturns (recession) and/or persistent stagnation (slow demand growth, usually after a recession) cause unemployed individuals to lose their job skills (commonly developed on the job) or to find that their skills have become obsolete, or become demotivated, disillusioned or depressed or lose job-seeking skills. In addition, employers may use time spent in unemployment as a screening tool, i.e., to weed out less desired employees in hiring decisions. Then, in times of an economic upturn, recovery, or "boom", the affected workers will not share in the prosperity, remaining unemployed for long periods (e.g., over 52 weeks). This makes unemployment "structural", i.e., extremely difficult to reduce simply by increasing the aggregate demand for products and labor without causing increased inflation. That is, it is possible that a ratchet effect in unemployment rates exists, so a short-term rise in unemployment rates tends to persist. For example, traditional anti-inflationary policy (the use of recession to fight inflation) leads to a permanently higher "natural" rate of unemployment (more scientifically known as the NAIRU). This occurs first because inflationary expectations are "sticky" downward due to wage and price rigidities (and so adapt slowly over time rather than being approximately correct as in theories of rational expectations) and second because labor markets do not clear instantly in response to unemployment.
The existence of hysteresis has been put forward as a possible explanation for the persistently high unemployment of many economies in the 1990s. Hysteresis has been invoked by Olivier Blanchard among others to explain the differences in long run unemployment rates between Europe and the United States. Labor market reform (usually meaning institutional change promoting more flexible wages, firing, and hiring) or strong demand-side economic growth may not therefore reduce this pool of long-term unemployed. Thus, specific targeted training programs are presented as a possible policy solution. However, the hysteresis hypothesis suggests such training programs are aided by persistently high demand for products (perhaps with incomes policies to avoid increased inflation), which reduces the transition costs out of unemployment and into paid employment easier. | 7 | Magnetic Ordering |
Galactomannans are polysaccharides consisting of a mannose backbone with galactose side groups, more specifically, a (1-4)-linked beta-D-mannopyranose backbone with branchpoints from their 6-positions linked to alpha-D-galactose, (i.e. 1-6-linked alpha-D-galactopyranose).
In order of increasing number of mannose-to-galactose ratio:
*fenugreek gum, mannose:galactose ~1:1
*guar gum, mannose:galactose ~2:1
*tara gum, mannose:galactose ~3:1
*locust bean gum or carob gum, mannose:galactose ~4:1
*cassia gum, mannose:galactose ~5:1
Galactomannans are often used in food products to increase the viscosity of the water phase.
Guar gum has been used to add viscosity to artificial tears, but is not as stable as carboxymethylcellulose. | 6 | Carbohydrates |
Founded in 2003 and formerly headquartered in East Norriton Township, Pennsylvania before moving to Winston-Salem, North Carolina in 2012, Tengion went public in 2010, after its stock has been approved for listing on the NASDAQ, through a $26 million IPO to help advance its research and development activities. Some of the groundbreaking regenerative medicine technologies of Dr. Anthony Atala, director of the Wake Forest Institute for Regenerative Medicine, were the core from where those research and development activities developed.
On September 4, 2012, Tengion received a notice from NASDAQ stating that the company had not regained compliance with NASDAQ Listing Rule 5550(b)(1) and that its common stock would cease trading on the NASDAQ Capital Market effective on September 6, 2012, and would begin trading on the OTCQB tier of the OTC Marketplace. The company was bought by former executives and creditors after declaring bankruptcy in 2014. | 2 | Tissue Engineering |
Treatment with RO is limited, resulting in low recoveries on high concentration (measured with electrical conductivity) and membrane fouling. RO applicability is limited by conductivity, organics, and scaling inorganic elements such as CaSO, Si, Fe and Ba. Low organic scaling can use two different technologies: spiral wound membrane, and (for high organic scaling, high conductivity and higher pressure (up to 90 bars)), disc tube modules with RO membranes can be used. Disc tube modules were redesigned for landfill leachate purification that is usually contaminated with organic material. Due to the cross-flow, it is given a flow booster pump that recirculates the flow over the membrane between 1.5 and 3 times before it is released as a concentrate. High velocity protects against membrane scaling and allows membrane cleaning. | 5 | Separation Processes |
Light-emitting capacitor, or LEC, is a term used since at least 1961 to describe electroluminescent panels. General Electric has patents dating to 1938 on flat electroluminescent panels that are still made as night lights and backlights for instrument panel displays. Electroluminescent panels are a capacitor where the dielectric between the outside plates is a phosphor that gives off photons when the capacitor is charged. By making one of the contacts transparent, the large area exposed emits light.
Electroluminescent automotive instrument panel backlighting, with each gauge pointer also an individual light source, entered production on 1960 Chrysler and Imperial passenger cars, and was continued successfully on several Chrysler vehicles through 1967 and marketed as "Panelescent Lighting". | 0 | Luminescence |
The energy levels needed to overcome the coulomb barrier, about 100 keV for D-T fuel, corresponds to millions of degrees, but is within the energy range that can be provided by even the smallest particle accelerators. For instance, the very first cyclotron, built in 1932, was capable of producing 4.8 MeV in a device that fit on a tabletop.
The original earthbound fusion reactions were created by such a device at the Cavendish Laboratory at Cambridge University. In 1934, Mark Oliphant, Paul Harteck and Ernest Rutherford used a new type of power supply to power a device not unlike an electron gun to shoot deuterium nuclei into a metal foil infused with deuterium, lithium or other light elements. This apparatus allowed them to study the nuclear cross section of the various reactions, and it was their work that produced the 100 keV figure.
The chance that any given deuteron will hit one of the deuterium atoms in the metal foil is vanishingly small. The experiment only succeeded because it ran for extended periods, and the rare reactions that did occur were so powerful that they could not be missed. But as the basis of a system for power production it simply wouldn't work; the vast majority of the accelerated deuterons goes right through the foil without undergoing a collision, and all the energy put into accelerating it is lost. The small number of reactions that do occur give off far less energy that what is fed into the accelerator.
A somewhat related concept was explored by Stanislaw Ulam and Jim Tuck at Los Alamos shortly after World War II. In this system, deuterium was infused into metal like the Cavendish experiments, but then formed into a cone and inserted into shaped charge warheads. Two such warheads were aimed at each other and fired, forming rapidly moving jets of deuterized metal that collided. These experiments were carried out in 1946 but failed to turn up any evidence of fusion reactions. | 3 | Nuclear Fusion |
This research, published in 2017, aimed to search for the solar neutrino effective magnetic moment. The search was completed using data from exposure from the Borexino experiment's second phase which consisted of data over 1291.5 days (3.54 years). The results yielded that the electron recoil spectrum shape was as expected with no major changes or deviations from it. | 3 | Nuclear Fusion |
The finding of a potential sperm donor and motivating them to actually donate sperm is typically called recruitment. A sperm bank can recruit donors by advertising, often in colleges, in local newspapers, and also on the internet.
A donor must be a fit and healthy male, normally between 18 and 45 years of age, and willing to undergo frequent and rigorous testing. The donor must also be willing to donate their sperm so that it can be used to impregnate people who are unrelated to and unknown by them. Some sperm banks require two screenings and a laboratory screening before a donor is eligible. The donor must agree to relinquish all legal rights to all children which result from their donations. The donor must produce their sperm at the sperm bank thus enabling the identity of the donor, once proven, always to be ascertained, and also enabling fresh samples of sperm to be produced for immediate processing. Some sperm banks have been accused of heightism due to minimum height requirements. | 1 | Cryobiology |
Traditional weakly coordinating anions, such as perchlorate, tetrafluoroborate, and hexafluorophosphate, will nonetheless coordinate to very electrophilic cations, making these counterions unsuitable for some complexes. The highly reactive species [CpZr(CH)], for example, has been reported to abstract F from PF. Starting in the 1980s, new types of weakly coordinating anions began to be developed. BAr′ anions are used as counterions for highly electrophilic, cationic transition metal species, as they are very weakly coordinating and unreactive towards electrophilic attack. One common method of generating these cationic species is via protonolysis of a dialkyl complexes or an olefin complex. For example, an electrophilic palladium catalyst, [(2,2′-bipyridine)Pd(CH)(CHCN)][BAr′], is prepared by protonating the dimethyl complex with Brookhart's acid. This electrophilic, cationic palladium species is used for the polymerization of olefins with carbon monoxide to polyketones in aprotic solvents. | 4 | Acids + Bases |
Sonoluminescence can occur when a sound wave of sufficient intensity induces a gaseous cavity within a liquid to collapse quickly. This cavity may take the form of a preexisting bubble or may be generated through a process known as cavitation. Sonoluminescence in the laboratory can be made to be stable so that a single bubble will expand and collapse over and over again in a periodic fashion, emitting a burst of light each time it collapses. For this to occur, a standing acoustic wave is set up within a liquid, and the bubble will sit at a pressure antinode of the standing wave. The frequencies of resonance depend on the shape and size of the container in which the bubble is contained.
Some facts about sonoluminescence:
* The light that flashes from the bubbles last between 35 and a few hundred picoseconds long, with peak intensities of the order of .
* The bubbles are very small when they emit light—about in diameter—depending on the ambient fluid (e.g., water) and the gas content of the bubble (e.g., atmospheric air).
* SBSL pulses can have very stable periods and positions. In fact, the frequency of light flashes can be more stable than the rated frequency stability of the oscillator making the sound waves driving them. The stability analyses of the bubble, however, show that the bubble itself undergoes significant geometric instabilities due to, for example, the Bjerknes forces and Rayleigh–Taylor instabilities.
* The addition of a small amount of noble gas (such as helium, argon, or xenon) to the gas in the bubble increases the intensity of the emitted light.
Spectral measurements have given bubble temperatures in the range from , the exact temperatures depending on experimental conditions including the composition of the liquid and gas. Detection of very high bubble temperatures by spectral methods is limited due to the opacity of liquids to short wavelength light characteristic of very high temperatures.
A study describes a method of determining temperatures based on the formation of plasmas. Using argon bubbles in sulfuric acid, the data shows the presence of ionized molecular oxygen , sulfur monoxide, and atomic argon populating high-energy excited states, which confirms a hypothesis that the bubbles have a hot plasma core. The ionization and excitation energy of dioxygenyl cations, which they observed, is . From this observation, they conclude the core temperatures reach at least —hotter than the surface of the Sun. | 0 | Luminescence |
As mentioned previously, is found in both diffuse and dense molecular clouds. By applying the reaction rate constants (α, β, and γ) corresponding to all of the currently available characterized reactions involving , it is possible to calculate k(T) for each of these reactions. By multiplying these k(T) by the relative abundances of the products, the relative rates (in cm/s) for each reaction at a given temperature can be determined. These relative rates can be made in absolute rates by multiplying them by the . By assuming for a dense cloud and for a diffuse cloud, the results indicate that most dominant formation and destruction mechanisms were the same for both cases. It should be mentioned that the relative abundances used in these calculations correspond to TMC-1, a dense molecular cloud, and that the calculated relative rates are therefore expected to be more accurate at . The three fastest formation and destruction mechanisms are listed in the table below, along with their relative rates. Note that the rates of these six reactions are such that they make up approximately 99% of hydronium ion's chemical interactions under these conditions. All three destruction mechanisms in the table below are classified as dissociative recombination reactions.
It is also worth noting that the relative rates for the formation reactions in the table above are the same for a given reaction at both temperatures. This is due to the reaction rate constants for these reactions having β and γ constants of 0, resulting in which is independent of temperature.
Since all three of these reactions produce either or OH, these results reinforce the strong connection between their relative abundances and that of . The rates of these six reactions are such that they make up approximately 99% of hydronium ion's chemical interactions under these conditions. | 4 | Acids + Bases |
Neutron generators are neutron source devices which contain compact linear particle accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deuterium, tritium, or a mixture of these two isotopes into a metal hydride target which also contains deuterium, tritium or a mixture of these isotopes. Fusion of deuterium atoms (D + D) results in the formation of a helium-3 ion and a neutron with a kinetic energy of approximately 2.5 MeV. Fusion of a deuterium and a tritium atom (D + T) results in the formation of a helium-4 ion and a neutron with a kinetic energy of approximately 14.1 MeV. Neutron generators have applications in medicine, security, and materials analysis.
The basic concept was first developed by Ernest Rutherfords team in the Cavendish Laboratory in the early 1930s. Using a linear accelerator driven by a Cockcroft–Walton generator, Mark Oliphant led an experiment that fired deuterium ions into a deuterium-infused metal foil and noticed that a small number of these particles gave off alpha particles. This was the first demonstration of nuclear fusion, as well as the first discovery of Helium-3 and tritium, created in these reactions. The introduction of new power sources has continually shrunk the size of these machines, from Oliphants that filled the corner of the lab, to modern machines that are highly portable. Thousands of such small, relatively inexpensive systems have been built over the past five decades.
While neutron generators do produce fusion reactions, the number of accelerated ions that cause these reactions is very low. It can be easily demonstrated that the energy released by these reactions is many times lower than the energy needed to accelerate the ions, so there is no possibility of these machines being used to produce net fusion power. A related concept, colliding beam fusion, attempts to address this issue using two accelerators firing at each other. | 3 | Nuclear Fusion |
The nuclear fusion process works as follows: five billion years ago, the new Sun formed when gravity pulled together a vast cloud of hydrogen and dust, from which the Earth and other planets also arose. The gravitational pull released energy and heated the early Sun, much in the way Helmholtz proposed.
Thermal energy appears as the motion of atoms and molecules: the higher the temperature of a collection of particles, the greater is their velocity and the more violent are their collisions. When the temperature at the center of the newly formed Sun became great enough for collisions between hydrogen nuclei to overcome their electric repulsion, and bring them into the short range of the attractive nuclear force, nuclei began to stick together. When this began to happen, protons combined into deuterium and then helium, with some protons changing in the process to neutrons (plus positrons, positive electrons, which combine with electrons and annihilate into gamma-ray photons). This released nuclear energy now keeps up the high temperature of the Sun's core, and the heat also keeps the gas pressure high, keeping the Sun at its present size, and stopping gravity from compressing it any more. There is now a stable balance between gravity and pressure.
Different nuclear reactions may predominate at different stages of the Sun's existence, including the proton–proton reaction and the carbon–nitrogen cycle—which involves heavier nuclei, but whose final product is still the combination of protons to form helium.
A branch of physics, the study of controlled nuclear fusion, has tried since the 1950s to derive useful power from nuclear fusion reactions that combine small nuclei into bigger ones, typically to heat boilers, whose steam could turn turbines and produce electricity. No earthly laboratory can match one feature of the solar powerhouse: the great mass of the Sun, whose weight keeps the hot plasma compressed and confines the nuclear furnace to the Sun's core. Instead, physicists use strong magnetic fields to confine the plasma, and for fuel they use heavy forms of hydrogen, which burn more easily. Magnetic traps can be rather unstable, and any plasma hot enough and dense enough to undergo nuclear fusion tends to slip out of them after a short time. Even with ingenious tricks, the confinement in most cases lasts only a small fraction of a second. | 3 | Nuclear Fusion |
Synthetic antiferromagnets (often abbreviated by SAF) are artificial antiferromagnets consisting of two or more thin ferromagnetic layers separated by a nonmagnetic layer. Dipole coupling of the ferromagnetic layers results in antiparallel alignment of the magnetization of the ferromagnets.
Antiferromagnetism plays a crucial role in giant magnetoresistance, as had been discovered in 1988 by the Nobel prize winners Albert Fert and Peter Grünberg (awarded in 2007) using synthetic antiferromagnets.
There are also examples of disordered materials (such as iron phosphate glasses) that become antiferromagnetic below their Néel temperature. These disordered networks frustrate the antiparallelism of adjacent spins; i.e. it is not possible to construct a network where each spin is surrounded by opposite neighbour spins. It can only be determined that the average correlation of neighbour spins is antiferromagnetic. This type of magnetism is sometimes called speromagnetism. | 7 | Magnetic Ordering |
Sensor-based sorting, is an umbrella term for all applications in which particles are detected using a sensor technique and rejected by an amplified mechanical, hydraulic or pneumatic process.
The technique is generally applied in mining, recycling and food processing and used in the particle size range between . Since sensor-based sorting is a single particle separation technology, the throughput is proportional to the average particle size and weight fed onto the machine. | 5 | Separation Processes |
A phosphoroscope is piece of experimental equipment devised in 1857 by physicist A. E. Becquerel to measure how long it takes a phosphorescent material to stop glowing after it has been excited.
It consists of two rotating disks with holes in them. The holes are arranged on each disk at equal angular intervals and a constant distance from the centre, but the holes in one disk do not align with the holes in the other. A sample of phosphorescent material is placed in between the two disks. Light coming in through a hole in one of the discs excites the phosphorescent material which then emits light for a short amount of time. The disks are then rotated and by changing their speed, the length of time the material glows can be determined. | 0 | Luminescence |
Pebble circuits are a very advantageous location for the application of sensor-based ore sorters. Usually it is hard waste recirculating and limiting the total mill capacity. In addition, the tonnage is significantly lower in comparison to the total run-of-mine stream, the size range is applicable and usually uniform and the particles' surfaces are clean. High impact on total mill capacity is reported in the literature. | 5 | Separation Processes |
The reaction mechanism is that of the related Hofmann degradation.
At first the carbonic acid amide (1) reacts with the sodium hypochlorite. After the separation of water and chloride an amine with a free bond is built 2. The intermediate (3) is generated by rearrangement. In the next step a hydrolysis takes place. Water is added at the carbon-atom with the number 1. A hydroxylic group is generated. The last step is that an acidic amide is separated and the aldehyde (4) is generated. | 6 | Carbohydrates |
There are several other bioprinting techniques which are less commonly used. Droplet-based bioprinting is a technique in which the bioink blend of cells and/or hydrogels are placed in droplets in precise positions. Most common amongst this approach are thermal and piezoelectric-drop-on-demand techniques. This method of bioprinting is often used experimentally with lung and ovarian cancer models. Thermal technologies use short duration signals to heat the bioink, inducing the formation of small bubbles which are ejected. Piezoelectric bioprinting has short duration current applied to a piezoelectric actuator, which induces a mechanical vibration capable of ejecting a small globule of bioink through the nozzle. A significant aspect of the study of droplet-based approaches to bioprinting is accounting for mechanical and thermal stress cells within the bioink experience near the nozzle-tip as they are extruded. | 2 | Tissue Engineering |
In general, ultraviolet detectors use either a solid-state device, such as one based on silicon carbide or aluminium nitride, or a gas-filled tube as the sensing element. UV detectors that are sensitive to UV in any part of the spectrum respond to irradiation by sunlight and artificial light. A burning hydrogen flame, for instance, radiates strongly in the 185- to 260-nanometer range and only very weakly in the IR region, whereas a coal fire emits very weakly in the UV band yet very strongly at IR wavelengths; thus, a fire detector that operates using both UV and IR detectors is more reliable than one with a UV detector alone. Virtually all fires emit some radiation in the UVC band, whereas the Suns radiation at this band is absorbed by the Earths atmosphere. The result is that the UV detector is "solar blind", meaning it will not cause an alarm in response to radiation from the Sun, so it can easily be used both indoors and outdoors.
UV detectors are sensitive to most fires, including hydrocarbons, metals, sulfur, hydrogen, hydrazine, and ammonia. Arc welding, electrical arcs, lightning, X-rays used in nondestructive metal testing equipment (though this is highly unlikely), and radioactive materials can produce levels that will activate a UV detection system. The presence of UV-absorbing gases and vapors will attenuate the UV radiation from a fire, adversely affecting the ability of the detector to detect flames. Likewise, the presence of an oil mist in the air or an oil film on the detector window will have the same effect. | 8 | Ultraviolet Radiation |
A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue". A second type of lamp produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These tubes are made for use in "bug zapper" insect traps, and are identified by the industry designation "BL". This stands for "blacklight".
Blacklight sources may be specially designed fluorescent lamps, mercury-vapor lamps, light-emitting diodes (LEDs), lasers, or incandescent lamps. In medicine, forensics, and some other scientific fields, such a light source is referred to as a Woods lamp, named after Robert Williams Wood, who invented the original Woods glass UV filters.
Although many other types of lamp emit ultraviolet light with visible light, black lights are essential when UV-A light without visible light is needed, particularly in observing fluorescence, the colored glow that many substances emit when exposed to UV. Black lights are employed for decorative and artistic lighting effects, diagnostic and therapeutic uses in medicine, the detection of substances tagged with fluorescent dyes, rock-hunting, scorpion-hunting, the detection of counterfeit money, the curing of plastic resins, attracting insects and the detection of refrigerant leaks affecting refrigerators and air conditioning systems. Strong sources of long-wave ultraviolet light are used in tanning beds. | 8 | Ultraviolet Radiation |
Conventional deuteron fusion is a two-step process, in which an unstable high-energy intermediary is formed:
:H + H → HeNuclear isomer| + 24 MeV
Experiments have shown only three decay pathways for this excited-state nucleus, with the branching ratio showing the probability that any given intermediate follows a particular pathway. The products formed via these decay pathways are:
:He → n + He + 3.3 MeV (ratio=50%)
:He → p + H + 4.0 MeV (ratio=50%)
:He → He + γ + 24 MeV (ratio=10)
Only about one in a million of the intermediaries take the third pathway, making its products very rare compared to the other paths. This result is consistent with the predictions of the Bohr model. If 1 watt (6.242 × 10 eV/s) were produced from ~2.2575 × 10 deuteron fusions per second, with the known branching ratios, the resulting neutrons and tritium (H) would be easily measured. Some researchers reported detecting He but without the expected neutron or tritium production; such a result would require branching ratios strongly favouring the third pathway, with the actual rates of the first two pathways lower by at least five orders of magnitude than observations from other experiments, directly contradicting both theoretically predicted and observed branching probabilities. Those reports of He production did not include detection of gamma rays, which would require the third pathway to have been changed somehow so that gamma rays are no longer emitted.
The known rate of the decay process together with the inter-atomic spacing in a metallic crystal makes heat transfer of the 24 MeV excess energy into the host metal lattice prior to the intermediary's decay inexplicable by conventional understandings of momentum and energy transfer, and even then there would be measurable levels of radiation. Also, experiments indicate that the ratios of deuterium fusion remain constant at different energies. In general, pressure and chemical environment cause only small changes to fusion ratios. An early explanation invoked the Oppenheimer–Phillips process at low energies, but its magnitude was too small to explain the altered ratios. | 3 | Nuclear Fusion |
There is a market for vials of processed sperm and for various reasons a sperm bank may sell-on stocks of vials which it holds known as onselling. The costs of screening of donors and storage of frozen donor sperm vials are not insignificant and in practice most sperm banks will try to dispose of all samples from an individual donor. The onselling of sperm therefore enables a sperm bank to maximize the sale and disposal of sperm samples which it has processed. The reasons for onselling may also be where part of, or even the main business of, a particular sperm bank is to process and store sperm rather than to use it in fertility treatments, or where a sperm bank is able to collect and store more sperm than it can use within nationally set limits. In the latter case a sperm bank may onsell sperm from a particular donor for use in another jurisdiction after the number of pregnancies achieved from that donor has reached its national maximum.
Sperm banks may supply other sperm banks or a fertility clinic with donor sperm to be used for achieving pregnancies.
Sperm banks may also supply sperm for research or educational purposes. | 1 | Cryobiology |
Plant cryopreservation consist of the storage of seeds, pollen, tissue, or embryos in liquid nitrogen. This method can be used for virtually indefinite storage of material without deterioration over a much greater time-period relative to all other methods of ex situ conservation. Cryopreservation is also used for the conservation of livestock genetics through cryoconservation of animal genetic resources. Technical limitations prevent the cryopreservation of many species, but cryobiology is a field of active research, and many studies concerning plants are underway. | 1 | Cryobiology |
Cryobiology is a bimonthly peer-reviewed scientific journal covering cryobiology. It was established in 1964 and is published by Elsevier on behalf of the Society for Cryobiology, of which it is the official journal. The editor-in-chief is D.M. Rawson (University of Bedfordshire). According to the Journal Citation Reports, the journal has a 2017 impact factor of 2.050. | 1 | Cryobiology |
There are various expansions or additional techniques that can be applied in IVF, which are usually not necessary for the IVF procedure itself, but would be virtually impossible or technically difficult to perform without concomitantly performing methods of IVF. | 1 | Cryobiology |
Andrei Sakharov and F.C. Frank predicted the phenomenon of muon-catalyzed fusion on theoretical grounds before 1950. Yakov Borisovich Zeldovich also wrote about the phenomenon of muon-catalyzed fusion in 1954. Luis W. Alvarez et al.', when analyzing the outcome of some experiments with muons incident on a hydrogen bubble chamber at Berkeley in 1956, observed muon-catalysis of exothermic p–d, proton and deuteron, nuclear fusion, which results in a helion, a gamma ray, and a release of about 5.5 MeV of energy. The Alvarez experimental results, in particular, spurred John David Jackson to publish one of the first comprehensive theoretical studies of muon-catalyzed fusion in his ground-breaking 1957 paper. This paper contained the first serious speculations on useful energy release from muon-catalyzed fusion. Jackson concluded that it would be impractical as an energy source, unless the "alpha-sticking problem" (see below) could be solved, leading potentially to an energetically cheaper and more efficient way of utilizing the catalyzing muons. | 3 | Nuclear Fusion |
* Potassium lactobionate: 100 mM
* KHPO: 25 mM
* MgSO: 5 mM
* Raffinose: 30 mM
* Adenosine: 5 mM
* Glutathione: 3 mM
* Allopurinol: 1 mM
* Hydroxyethyl starch: 50 g/L | 1 | Cryobiology |
The cold environments that psychrophiles inhabit are ubiquitous on Earth, as a large fraction of the planetary surface experiences temperatures lower than 10 °C. They are present in permafrost, polar ice, glaciers, snowfields and deep ocean waters. These organisms can also be found in pockets of sea ice with high salinity content. Microbial activity has been measured in soils frozen below −39 °C. In addition to their temperature limit, psychrophiles must also adapt to other extreme environmental constraints that may arise as a result of their habitat. These constraints include high pressure in the deep sea, and high salt concentration on some sea ice. | 1 | Cryobiology |
* Imaging: contrast agents in magnetic resonance imaging (MRI)
* Magnetic separation: cell-, DNA-, protein- separation, RNA fishing
* Treatments: targeted drug delivery, magnetic hyperthermia, magnetofection | 7 | Magnetic Ordering |
Glow sticks are used by militaries, and occasionally also police tactical units, as light sources during night operations or close-quarters combat in dark areas. They are also used to mark secured areas or objects of note. When worn, they can be used to identify friendly soldiers during nighttime operations. | 0 | Luminescence |
No evidence of harm to the fetus has been found when used during pregnancy. It is generally regarded as safe during breastfeeding. | 6 | Carbohydrates |
Electrical implants are being used to relieve pain from rheumatoid arthritis. The electric implant is embedded in the neck of patients with rheumatoid arthritics, the implant sends electrical signals to electrodes in the vagus nerve. The application of this device is being tested an alternative to medicating people with rheumatoid arthritis for their lifetime. | 2 | Tissue Engineering |
Indias top court ruled that authorities must regulate the sale of acid. The Supreme Courts ruling on 16 July 2013, came after an incident in which four sisters suffered severe burns after being attacked with acid by two men on a motorbike. Acid which is designed to clean rusted tools is often used in the attacks can be bought across the counter. But the judges said the buyer of such acids should in future have to provide a photo identity card to any retailer when they make a purchase. The retailers must register the name and address of the buyer. In 2013, section 326 A of Indian Penal Code was enacted by the Indian Parliament to ensure enhanced punishment for acid throwing. | 4 | Acids + Bases |
Guillemin effect is one of the magnetomechanical effects. It is connected with the tendency of a previously bent rod, made of magnetostrictive material, to be straightened, when subjected to magnetic field applied in the direction of rod's axis. | 7 | Magnetic Ordering |
According to the Landau theory applied to the mean field picture for magnetism, the free energy of a ferromagnetic material close to a phase transition can be written as:
where , the magnetization, is the order parameter, is the applied magnetic field, is the critical temperature, and are material constants.
Close to the phase transition, this gives a relation for the magnetization order parameter:
where is a dimensionless measure of the temperature.
Thus in a graph plotting vs. for various temperatures, the line without an intercept corresponds to the dependence at the critical temperature. Thus along with providing evidence for the existence of a ferromagnetic phase, the Arrott plot can also be used to determine the critical temperature for the phase transition. | 7 | Magnetic Ordering |
Oleum is used in the manufacture of many explosives with the notable exception of nitrocellulose. (In modern manufacturing of nitrocellulose, the HSO concentration is often adjusted using oleum.) The chemical requirements for explosives manufacture often require anhydrous mixtures containing nitric acid and sulfuric acid. Ordinary commercial grade nitric acid consists of the constant boiling azeotrope of nitric acid and water, and contains 68% nitric acid. Mixtures of ordinary nitric acid in sulfuric acid therefore contain substantial amounts of water and are unsuitable for processes such as those that occur in the manufacture of trinitrotoluene.
The synthesis of RDX and certain other explosives does not require oleum.
Anhydrous nitric acid, referred to as white fuming nitric acid, can be used to prepare water-free nitration mixtures, and this method is used in laboratory scale operations where the cost of material is not of primary importance. Fuming nitric acid is hazardous to handle and transport, because it is extremely corrosive and volatile. For industrial use, such strong nitration mixtures are prepared by mixing oleum with ordinary commercial nitric acid so that the free sulfur trioxide in the oleum consumes the water in the nitric acid. | 4 | Acids + Bases |
A pure fusion weapon is a hypothetical hydrogen bomb design that does not need a fission "primary" explosive to ignite the fusion of deuterium and tritium, two heavy isotopes of hydrogen used in fission-fusion thermonuclear weapons. Such a weapon would require no fissile material and would therefore be much easier to develop in secret than existing weapons. Separating weapons-grade uranium (U-235) or breeding plutonium (Pu-239) requires a substantial and difficult-to-conceal industrial investment, and blocking the sale and transfer of the needed machinery has been the primary mechanism to control nuclear proliferation to date. | 3 | Nuclear Fusion |
In gene-activated matrix technology (GAM), cytokines and growth factors could be delivered not as recombinant proteins but as plasmid genes. GAM is one of the tissue engineering approaches to wound healing. Following gene delivery, the recombinant cytokine could be expressed in situ by endogenous would healing cells – in small amounts but for a prolonged period of time – leading to reproducible tissue regeneration. The matrix can be modified by incorporating a viral vector, mRNA or DNA bound to a delivery system, or a naked plasmid. | 2 | Tissue Engineering |
* co-culture with stromal cells or feeder cells, and on specific culture substrates:
support cells and matrices provide developmental-like environmental signals.
* 3D cell aggregate formation, termed embryoid bodies (EBs): the aggregate aim at mimicking early embryonic development and instructing the cell differentiation.
* culture in presence of fetal bovine serum, removal of pluripotency factors. | 2 | Tissue Engineering |
* The general mathematical formalism used to describe and solve the Heisenberg model and certain generalizations is developed in the article on the Potts model.
* In the continuum limit the Heisenberg model (2) gives the following equation of motion
:This equation is called the continuous classical Heisenberg ferromagnet equation or shortly Heisenberg model and is integrable in the sense of soliton theory. It admits several integrable and nonintegrable generalizations like Landau-Lifshitz equation, Ishimori equation and so on. | 7 | Magnetic Ordering |
A magnetic particle with uniaxial anisotropy has one easy axis. If the easy axis is in the direction, the anisotropy energy can be expressed as one of the forms:
where is the volume, the anisotropy constant, and the angle between the easy axis and the particle's magnetization. When shape anisotropy is explicitly considered, the symbol is often used to indicate the anisotropy constant, instead of . In the widely used Stoner–Wohlfarth model, the anisotropy is uniaxial. | 7 | Magnetic Ordering |
Ultraviolet in sewage treatment is commonly replacing chlorination. This is in large part because of concerns that reaction of the chlorine with organic compounds in the waste water stream could synthesize potentially toxic and long lasting chlorinated organics and also because of the environmental risks of storing chlorine gas or chlorine containing chemicals. Individual wastestreams to be treated by UVGI must be tested to ensure that the method will be effective due to potential interferences such as suspended solids, dyes, or other substances that may block or absorb the UV radiation. According to the World Health Organization, "UV units to treat small batches (1 to several liters) or low flows (1 to several liters per minute) of water at the community level are estimated to have costs of US$20 per megaliter, including the cost of electricity and consumables and the annualized capital cost of the unit."
Large-scale urban UV wastewater treatment is performed in cities such as Edmonton, Alberta. The use of ultraviolet light has now become standard practice in most municipal wastewater treatment processes. Effluent is now starting to be recognized as a valuable resource, not a problem that needs to be dumped. Many wastewater facilities are being renamed as water reclamation facilities, whether the wastewater is discharged into a river, used to irrigate crops, or injected into an aquifer for later recovery. Ultraviolet light is now being used to ensure water is free from harmful organisms. | 8 | Ultraviolet Radiation |
Davis and Bahcall continued their work to understand where they may have gone wrong or what they were missing, along with other astrophysicists who also did their own research on the subject. Many reviewed and redid Bahcall's calculations in the 1970s and 1980s, and although there was more data making the results more precise, the difference still remained. Davis even repeated his experiment changing the sensitivity and other factors to make sure nothing was overlooked, but he found nothing and the results still showed "missing" neutrinos. By the end of the 1970s, the widely expected result was the experimental data yielded about 39% of the calculated number of neutrinos. In 1969, Bruno Pontecorvo, an Italo-Russian astrophysicist, suggested a new idea that maybe we do not quite understand neutrinos like we think we do, and that neutrinos could change in some way, meaning the neutrinos that are released by the sun changed form and were no longer neutrinos the way neutrinos were thought off by the time they reached Earth where the experiment was conducted. This theory Pontecorvo had would make sense in accounting for the discrepancy between the experimental and theoretical results that persisted. | 3 | Nuclear Fusion |
Both sphalerite and wurtzite are intrinsic, wide-bandgap semiconductors. These are prototypical II-VI semiconductors, and they adopt structures related to many of the other semiconductors, such as gallium arsenide. The cubic form of ZnS has a band gap of about 3.54 electron volts at 300 kelvins, but the hexagonal form has a band gap of about 3.91 electron volts. ZnS can be doped as either an n-type semiconductor or a p-type semiconductor. | 0 | Luminescence |
The post-bioprinting process is necessary to create a stable structure from the biological material. If this process is not well-maintained, the mechanical integrity and function of the 3D printed object is at risk. To maintain the object, both mechanical and chemical stimulations are needed. These stimulations send signals to the cells to control the remodeling and growth of tissues. In addition, in recent development, bioreactor technologies have allowed the rapid maturation of tissues, vascularization of tissues and the ability to survive transplants.
Bioreactors work in either providing convective nutrient transport, creating microgravity environments, changing the pressure causing solution to flow through the cells, or adding compression for dynamic or static loading. Each type of bioreactor is ideal for different types of tissue, for example compression bioreactors are ideal for cartilage tissue. | 2 | Tissue Engineering |
The Cells Alive System (CAS) is a line of commercial freezers manufactured by ABI Corporation, Ltd. of Chiba, Japan claimed to preserve food with greater freshness than ordinary freezing by using electromagnetic fields and mechanical vibrations to limit ice crystal formation that destroys food texture. They also are claimed to increase tissue survival without having its water replaced by cryogenically compatible fluids; whether they have any effect is unclear. The freezers have attracted attention among organ banking and transplantation surgeons, as well as the food processing industry. | 1 | Cryobiology |
In 1985, Donna Strickland and Gérard Mourou invented a method to amplify laser pulses by "chirping". This changed a single wavelength into a full spectrum. The system amplified the beam at each wavelength and then reversed the beam into one color. Chirp pulsed amplification became instrumental for NIF and the Omega EP system.
LANL constructed a series of laser facilities. They included Gemini (a two beam system), Helios (eight beams), Antares (24 beams) and Aurora (96 beams). The program ended in the early nineties with a cost on the order of one billion dollars.
In 1987, Akira Hasegawa noticed that in a dipolar magnetic field, fluctuations tended to compress the plasma without energy loss. This effect was noticed in data taken by Voyager 2, when it encountered Uranus. This observation became the basis for a fusion approach known as the levitated dipole.
In tokamaks, the Tore Supra was under construction from 1983 to 1988 in Cadarache, France. Its superconducting magnets permitted it to generate a strong permanent toroidal magnetic field. First plasma came in 1988.
In 1983, JET achieved first plasma. In 1985, the Japanese tokamak, JT-60 produced its first plasmas. In 1988, the T-15 a Soviet tokamak was completed, the first to use (helium-cooled) superconducting magnets.
In 1998, the T-15 Soviet tokamak with superconducting helium-cooled coils was completed. | 3 | Nuclear Fusion |
Colliding beam fusion (CBF), or colliding beam fusion reactor (CBFR), is a class of fusion power concepts that are based on two or more intersecting beams of fusion fuel ions that are independently accelerated to fusion energies using a variety of particle accelerator designs or other means. One of the beams may be replaced by a static target, in which case the approach is termed accelerator based fusion or beam-target fusion, but the physics is the same as colliding beams.
CBFRs face several problems that have limited their ability to be seriously considered as candidates for fusion power. When two ions collide, they are more likely to scatter than to fuse. Magnetic confinement fusion reactors overcome this problem using a bulk plasma and confining it for some time so that the ions have many thousands of chances to collide. Two beams colliding give ions little time to interact before the beams fly apart. This limits how much fusion power a beam-beam machine can make.
CBFR offers more efficient ways to provide the activation energy for fusion, by directly accelerating individual particles rather than heating a bulk fuel. The CBFR reactants are naturally non-thermal which gives them advantages, especially that they can directly carry enough energy to overcome the Coulomb barrier of aneutronic fusion fuels. Several designs have sought to address the shortcomings of earlier CBFRs, including Migma, MARBLE, MIX, and other beam-based concepts. These attempt to overcome the fundamental challenges of CBFR by applying radio waves, bunching beams together, increasing recirculation, or applying some quantum effects. None of these approaches have succeeded yet. | 3 | Nuclear Fusion |
In 1896, Beijerinck first noted an incompatibility in solutions of agar, a water-soluble polymer, with soluble starch or gelatine. Upon mixing, they separated into two immiscible phases.
Subsequent investigation led to the determination of many other aqueous biphasic systems, of which the polyethylene glycol (PEG) - dextran system is the most extensively studied. Other systems that form aqueous biphases are: PEG - sodium carbonate or PEG and phosphates, citrates or sulfates. Aqueous biphasic systems are used during downstream processing mainly in biotechnological and chemical industries. | 5 | Separation Processes |
EFDA has two locations, which each house a so-called Close Support Unit (CSU), responsible for part of EFDA's activities. The EFDA-CSU Garching is located in Garching, near Munich (Germany), and is hosted by the German [http://www.ipp.mpg.de/ Max-Planck Institut für Plasmaphysik]. [https://web.archive.org/web/20090723101818/http://www.jet.efda.org/ EFDA-CSU Culham] is hosted by the [http://www.ccfe.ac.uk/ CCFE] laboratory in Culham (UK), home of the Joint European Torus facilities.
A large number of scientists and engineers from the associated laboratories work together on different projects of EFDA. The main task of the Close Support Units is to ensure that these diverse activities are integrated in a coordinated European Fusion Programme.
The EFDA management consists of the EFDA Leader (Dr. Francesco Romanelli) and the EFDA-Associate Leader for JET (Dr. Francesco Romanelli). | 3 | Nuclear Fusion |
Contraceptive implants are primarily used to prevent unintended pregnancy and treat conditions such as non-pathological forms of menorrhagia. Examples include copper- and hormone-based intrauterine devices. | 2 | Tissue Engineering |
Regenerative medicine deals with the "process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function". This field holds the promise of engineering damaged tissues and organs by stimulating the body's own repair mechanisms to functionally heal previously irreparable tissues or organs.
Regenerative medicine also includes the possibility of growing tissues and organs in the laboratory and implanting them when the body cannot heal itself. When the cell source for a regenerated organ is derived from the patient's own tissue or cells, the challenge of organ transplant rejection via immunological mismatch is circumvented. This approach could alleviate the problem of the shortage of organs available for donation.
Some of the biomedical approaches within the field of regenerative medicine may involve the use of stem cells. Examples include the injection of stem cells or progenitor cells obtained through directed differentiation (cell therapies); the induction of regeneration by biologically active molecules administered alone or as a secretion by infused cells (immunomodulation therapy); and transplantation of in vitro grown organs and tissues (tissue engineering). | 2 | Tissue Engineering |
The proper combination of chemicals is selected for decellularization depending on the thickness, extracellular matrix composition, and intended use of the tissue or organ. For example, enzymes would not be used on a collagenous tissue because they disrupt the connective tissue fibers. However, when collagen is not present in a high concentration or needed in the tissue, enzymes can be a viable option for decellularization. The chemicals used to kill and remove the cells include acids, alkaline treatments, ionic detergents, non-ionic detergents, and zwitterionic detergents.
The ionic detergent, sodium dodecyl sulfate (SDS), is commonly used because of its high efficacy for lysing cells without significant damage to the ECM. Detergents act effectively to lyse the cell membrane and expose the contents to further degradation. After SDS lyses the cell membrane, endonucleases and exonucleases degrade the genetic contents, while other components of the cell are solubilized and washed out of the matrix. SDS is commonly used even though it has a tendency to slightly disrupt the ECM structure. Alkaline and acid treatments can be effective companions with an SDS treatment due to their ability to degrade nucleic acids and solubilize cytoplasmic inclusions.
The most well known non-ionic detergent is Triton X-100, which is popular because of its ability to disrupt lipid-lipid and lipid-protein interactions. Triton X-100 does not disrupt protein-protein interactions, which is beneficial to keeping the ECM intact. EDTA is a chelating agent that binds calcium, which is a necessary component for proteins to interact with one another. By making calcium unavailable, EDTA prevents the integral proteins between cells from binding to one another. EDTA is often used with trypsin, an enzyme that acts as a protease to cleave the already existing bonds between integral proteins of neighboring cells within a tissue. Together, the EDTA-Trypsin combination make a good team for decellularizing tissues. | 2 | Tissue Engineering |
* The Career Achievement Award is aimed towards a recognition of individuals who have made outstanding contributions to the field of TERM and have carried out most of their career in the TERMIS-EU geographical area.
* The Mid Terms Career Award has been established in 2020 to recognize individuals that are within 10–20 years after obtaining their PhD, with a successful research group and clear evidence of outstanding performance.
* The Robert Brown Early Career Principal Investigator Award recognizes individuals that are within 2–10 years after obtaining their PhD, with clear evidence of a growing profile. | 2 | Tissue Engineering |
One last area that has been actively studied is the synergy of different materials in promoting superior electroactive performance. Whether through various charge transport material, electrochemical species, or morphologies, exploiting the synergetic relationship between different materials has paved the way for even newer counter electrode materials.
In 2016, Lu et al. mixed nickel cobalt sulfide microparticles with reduced graphene oxide (rGO) nanoflakes to create the counter electrode. Lu et al. discovered not only that the rGO acted as a co-catalyst in accelerating the triiodide reduction, but also that the microparticles and rGO had a synergistic interaction that decreased the charge transfer resistance of the overall system. Although the efficiency of this system was slightly lower than its platinum analog (efficiency of NCS/rGO system: 8.96%; efficiency of Pt system: 9.11%), it provided a platform on which further research can be conducted. | 8 | Ultraviolet Radiation |
Stripping is mainly conducted in trayed towers (plate columns) and packed columns, and less often in spray towers, bubble columns, and centrifugal contactors.
Trayed towers consist of a vertical column with liquid flowing in the top and out the bottom. The vapor phase enters in the bottom of the column and exits out of the top. Inside of the column are trays or plates. These trays force the liquid to flow back and forth horizontally while the vapor bubbles up through holes in the trays. The purpose of these trays is to increase the amount of contact area between the liquid and vapor phases.
Packed columns are similar to trayed columns in that the liquid and vapor flows enter and exit in the same manner. The difference is that in packed towers there are no trays. Instead, packing is used to increase the contact area between the liquid and vapor phases. There are many different types of packing used and each one has advantages and disadvantages. | 5 | Separation Processes |
An unusually exotic hypothesis of sonoluminescence, which has received much popular attention, is the Casimir energy hypothesis suggested by noted physicist Julian Schwinger and more thoroughly considered in a paper by Claudia Eberlein of the University of Sussex. Eberlein's paper suggests that the light in sonoluminescence is generated by the vacuum within the bubble in a process similar to Hawking radiation, the radiation generated at the event horizon of black holes. According to this vacuum energy explanation, since quantum theory holds that vacuum contains virtual particles, the rapidly moving interface between water and gas converts virtual photons into real photons. This is related to the Unruh effect or the Casimir effect. The argument has been made that sonoluminescence releases too large an amount of energy and releases the energy on too short a time scale to be consistent with the vacuum energy explanation, although other credible sources argue the vacuum energy explanation might yet prove to be correct. | 0 | Luminescence |
Calculation can be employed to determine the nuclear binding energy of nuclei. The calculation involves determining the mass defect, converting it into energy, and expressing the result as energy per mole of atoms, or as energy per nucleon. | 3 | Nuclear Fusion |
The black-and-white television screens require an emission color close to white. Usually, a combination of phosphors is employed.
The most common combination is (blue + yellow). Other ones are (blue + yellow), and (blue + green + red – does not contain cadmium and has poor efficiency). The color tone can be adjusted by the ratios of the components.
As the compositions contain discrete grains of different phosphors, they produce image that may not be entirely smooth. A single, white-emitting phosphor, overcomes this obstacle. Due to its low efficiency, it is used only on very small screens.
The screens are typically covered with phosphor using sedimentation coating, where particles suspended in a solution are let to settle on the surface. | 0 | Luminescence |
A spin chain is a type of model in statistical physics. Spin chains were originally formulated to model magnetic systems, which typically consist of particles with magnetic spin located at fixed sites on a lattice. A prototypical example is the quantum Heisenberg model. Interactions between the sites are modelled by operators which act on two different sites, often neighboring sites.
They can be seen as a quantum version of statistical lattice models, such as the Ising model, in the sense that the parameter describing the spin at each site is promoted from a variable taking values in a discrete set (typically , representing spin up and spin down) to a variable taking values in a vector space (typically the spin-1/2 or two-dimensional representation of ). | 7 | Magnetic Ordering |
The use of lithium to distinguish candidate brown dwarfs from low-mass stars is commonly referred to as the lithium test. Heavier stars like the Sun can retain lithium in their outer atmospheres, which never get hot enough for lithium depletion, but those are distinguishable from brown dwarfs by their size. Brown dwarfs at the high end of their mass range (60–75 M) can be hot enough to deplete their lithium when they are young. Dwarfs of mass greater than 65 M can burn off their lithium by the time they are half a billion years old; thus, this test is not perfect. | 3 | Nuclear Fusion |
The magnetocrystalline anisotropy parameters are generally defined for ferromagnets that are constrained to remain undeformed as the direction of magnetization changes. However, coupling between the magnetization and the lattice does result in deformation, an effect called magnetostriction. To keep the lattice from deforming, a stress must be applied. If the crystal is not under stress, magnetostriction alters the effective magnetocrystalline anisotropy. If a ferromagnet is single domain (uniformly magnetized), the effect is to change the magnetocrystalline anisotropy parameters.
In practice, the correction is generally not large. In hexagonal crystals, there is no change in . In cubic crystals, there is a small change, as in the table below. | 7 | Magnetic Ordering |
The major complication of IVF is the risk of multiple births. This is directly related to the practice of transferring multiple embryos at embryo transfer. Multiple births are related to increased risk of pregnancy loss, obstetrical complications, prematurity, and neonatal morbidity with the potential for long term damage. Strict limits on the number of embryos that may be transferred have been enacted in some countries (e.g. Britain, Belgium) to reduce the risk of high-order multiples (triplets or more), but are not universally followed or accepted. Spontaneous splitting of embryos in the uterus after transfer can occur, but this is rare and would lead to identical twins. A double blind, randomised study followed IVF pregnancies that resulted in 73 infants, and reported that 8.7% of singleton infants and 54.2% of twins had a birth weight of less than . There is some evidence that making a double embryo transfer during one cycle achieves a higher live birth rate than a single embryo transfer; but making two single embryo transfers in two cycles has the same live birth rate and would avoid multiple pregnancies. | 1 | Cryobiology |
In the muon-catalyzed fusion of most interest, a positively charged deuteron (d), a positively charged triton (t), and a muon essentially form a positively charged muonic molecular heavy hydrogen ion (d–μ–t). The muon, with a rest mass 207 times greater than the rest mass of an electron, is able to drag the more massive triton and deuteron 207 times closer together to each other
in the muonic (d–μ–t) molecular ion than can an electron in the corresponding electronic (d–e–t) molecular ion. The average separation between the triton and the deuteron in the electronic molecular ion is about one angstrom (100 pm), so the average separation between the triton and the deuteron in the muonic molecular ion is 207 times smaller than that. Due to the strong nuclear force, whenever the triton and the deuteron in the muonic molecular ion happen to get even closer to each other during their periodic vibrational motions, the probability is very greatly enhanced that the positively charged triton and the positively charged deuteron would undergo quantum tunnelling through the repulsive Coulomb barrier that acts to keep them apart. Indeed, the quantum mechanical tunnelling probability depends roughly exponentially on the average separation between the triton and the deuteron, allowing a single muon to catalyze the d–t nuclear fusion in less than about half a picosecond, once the muonic molecular ion is formed.
The formation time of the muonic molecular ion is one of the "rate-limiting steps" in muon-catalyzed fusion that can easily take up to ten thousand or more picoseconds in a liquid molecular deuterium and tritium mixture (D, DT, T), for example. Each catalyzing muon thus spends most of its ephemeral existence of 2.2 microseconds, as measured in its rest frame, wandering around looking for suitable deuterons and tritons with which to bind.
Another way of looking at muon-catalyzed fusion is to try to visualize the ground state orbit of a muon around either a deuteron or a triton. Suppose the muon happens to have fallen into an orbit around a deuteron initially, which it has about a 50% chance of doing if there are approximately equal numbers of deuterons and tritons present, forming an electrically neutral muonic deuterium atom (d–μ) that acts somewhat like a "fat, heavy neutron" due both to its relatively small size (again, 207 times smaller than an electrically neutral electronic deuterium atom (d–e)) and to the very effective "shielding" by the muon of the positive charge of the proton in the deuteron. Even so, the muon still has a much greater chance of being transferred to any triton that comes near enough to the muonic deuterium than it does of forming a muonic molecular ion. The electrically neutral muonic tritium atom (t–μ) thus formed will act somewhat like an even "fatter, heavier neutron," but it will most likely hang on to its muon, eventually forming a muonic molecular ion, most likely due to the resonant formation of a hyperfine molecular state within an entire deuterium molecule D (d=e=d), with the muonic molecular ion acting as a "fatter, heavier nucleus" of the "fatter, heavier" neutral "muonic/electronic" deuterium molecule ([d–μ–t]=e=d), as predicted by Vesman, an Estonian graduate student, in 1967.
Once the muonic molecular ion state is formed, the shielding by the muon of the positive charges of the proton of the triton and the proton of the deuteron from each other allows the triton and the deuteron to tunnel through the Coulomb barrier in time span of order of a nanosecond The muon survives the d–t muon-catalyzed nuclear fusion reaction and remains available (usually) to catalyze further d–t muon-catalyzed nuclear fusions. Each exothermic d–t nuclear fusion releases about 17.6 MeV of energy in the form of a "very fast" neutron having a kinetic energy of about 14.1 MeV and an alpha particle α (a helium-4 nucleus) with a kinetic energy of about 3.5 MeV. An additional 4.8 MeV can be gleaned by having the fast neutrons moderated in a suitable "blanket" surrounding the reaction chamber, with the blanket containing lithium-6, whose nuclei, known by some as "lithions," readily and exothermically absorb thermal neutrons, the lithium-6 being transmuted thereby into an alpha particle and a triton. | 3 | Nuclear Fusion |
Some amphibians and reptiles have the ability to regenerate limbs, eyes, spinal cords, hearts, intestines, and upper and lower jaws. The Japanese fire belly newt can regenerate its eye lens 18 times over a period of 16 years and retain its structural and functional properties. The cells at the site of the injury have the ability to undifferentiate, reproduce rapidly, and differentiate again to create a new limb or organ.
Hox genes are a group of related genes that control the body plan of an embryo along the head-tail axis. They are responsible for body segment differentiation and express the arrangement of numerous body components during initial embryonic development. Primarily, these sets of genes are utilized during the development of body plans by coding for the transcription factors that trigger production of body segment specific structures. Additionally in most animals, these genes are laid out along the chromosome similar to the order in which they are expressed along the anterior–posterior axis.
Variants of the Hox genes are found almost in every phylum with the exception of the sponge which use a different type of developmental genes. The homology of these genes is of important interest to scientists as they may hold more answers to the evolution of many species. In fact, these genes demonstrate such a high degree of homology that a human Hox gene variant – HOXB4 – could mimic the function of its homolog in the fruit fly (Drosophila). Studies suggest that the regulation and other target genes in different species are actually what causes such a great difference in phenotypic difference between species.
Hox genes contain a DNA sequence known as the homeobox that are involved in the regulation of patterns of anatomical development. They contain a specific DNA sequence with the aim of providing instructions for making a string of 60 protein building blocks - amino acids- which are referred to as the homeodomain. Most homeodomain-containing proteins function as transcription factors and fundamentally bind and regulate the activity of different genes. The homeodomain is the segment of the protein that binds to precise regulatory regions of the target genes. Genes within the homeobox family are implicated in a wide variety of significant activities during growth. These activities include directing the development of limbs and organs along the anterior-posterior axis and regulating the process by which cells mature to carry out specific functions, a process known as cellular differentiation. Certain homeobox genes can act tumor suppressors, which means they help prevent cells from growing and dividing too rapidly or in an uncontrolled way.
Due to the fact that homeobox genes have so many important functions, mutations in these genes are accountable for a wide array of developmental disorders. Changes in certain homeobox genes often result in eye disorders, cause abnormal head, face, and tooth development. Additionally, increased or decreased activity of certain homeobox genes has been associated with several forms of cancer later in life. | 2 | Tissue Engineering |
Heat is primarily generated in muscle tissue, including the heart, and in the liver, while it is lost through the skin (90%) and lungs (10%). Heat production may be increased two- to four-fold through muscle contractions (i.e. exercise and shivering). The rate of heat loss is determined, as with any object, by convection, conduction, and radiation. The rates of these can be affected by body mass index, body surface area to volume ratios, clothing and other environmental conditions.
Many changes to physiology occur as body temperatures decrease. These occur in the cardiovascular system leading to the Osborn J wave and other dysrhythmias, decreased central nervous system electrical activity, cold diuresis, and non-cardiogenic pulmonary edema.
Research has shown that glomerular filtration rates (GFR) decrease as a result of hypothermia. In essence, hypothermia increases preglomerular vasoconstriction, thus decreasing both renal blood flow (RBF) and GFR. | 1 | Cryobiology |
Researchers in the field do not agree on a theory for cold fusion. One proposal considers that hydrogen and its isotopes can be absorbed in certain solids, including palladium hydride, at high densities. This creates a high partial pressure, reducing the average separation of hydrogen isotopes. However, the reduction in separation is not enough to create the fusion rates claimed in the original experiment, by a factor of ten. It was also proposed that a higher density of hydrogen inside the palladium and a lower potential barrier could raise the possibility of fusion at lower temperatures than expected from a simple application of Coulomb's law. Electron screening of the positive hydrogen nuclei by the negative electrons in the palladium lattice was suggested to the 2004 DOE commission, but the panel found the theoretical explanations not convincing and inconsistent with current physics theories. | 3 | Nuclear Fusion |
Valvular heart disease is a major cause of death globally. Both mechanical valves and fixed biological xenograft or homografts used clinically have many drawbacks. One study focused on fibrin-based heart valves to assess structure and mechanical durability on sheep revealed promising potential for patient originated valve replacements. From autologous arterial-derived cells and fibrin scaffold, tissue engineered heart valves are formed, then mechanically conditioned and transplanted into the pulmonary trunk of the same animals. The preliminary result are potentially hopeful towards autologous heart valve production. | 2 | Tissue Engineering |
An essential preliminary to the development of kidney storage and transplantation was the work of Alexis Carrel in developing methods for vascular anastomosis. Carrel went on to describe the first kidney transplants, which were performed in dogs in 1902; Ullman independently described similar experiments in the same year. In these experiments kidneys were transplanted without there being any attempt at storage.
The crucial step in making in vitro storage of kidneys possible, was the demonstration by Fuhrman in 1943, of a reversible effect of hypothermia on the metabolic processes of isolated tissues. Prior to this, kidneys had been stored at normal body temperatures using blood or diluted blood perfusates, but no successful reimplantations had been made. Fuhrman showed that slices of rat kidney cortex and brain withstood cooling to 0.2 °C for one hour at which temperature their oxygen consumption was minimal. When the slices were rewarmed to 37 °C their oxygen consumption recovered to normal.
The beneficial effect of hypothermia on ischaemic intact kidneys was demonstrated by Owens in 1955 when he showed that, if dogs were cooled to 23-26 °C, and their thoracic aortas were occluded for 2 hours, their kidneys showed no apparent damage when the dogs were rewarmed. This protective effect of hypothermia on renal ischaemic damage was confirmed by Bogardus who showed a protective effect from surface cooling of dog kidneys whose renal pedicles were clamped in situ for 2 hours. Moyer demonstrated the applicability of these dog experiments to the human, by showing the same effect on dog and human kidney function from the same periods of hypothermic ischaemia.
It was not until 1958 that it was shown that intact dog kidneys would survive ischaemia even better if they were cooled to lower temperatures. Stueber showed that kidneys would survive in situ clamping of the renal pedicle for 6 hours if the kidneys were cooled to 0-5 °C by being placed in a cooling jacket, and Schloerb showed that a similar technique with cooling of heparinised dog kidneys to 2-4 °C gave protection for 8 hours but not 12 hours. Schloerb also attempted in vitro storage and auto-transplantation of cooled kidneys, and had one long term survivor after 4 hours kidney storage followed by reimplantation and immediate contralateral nephrectomy. He also had a near survivor, after 24-hour kidney storage and delayed contralateral nephrectomy, in a dog that developed a late arterial thrombosis in the kidney.
These methods of surface cooling were improved by the introduction of techniques in which the kidney's vascular system was flushed out with cold fluid prior to storage. This had the effect of increasing the speed of cooling of the kidney and removed red cells from the vascular system. Kiser used this technique to achieve successful 7 hours in vitro storage of a dog kidney, when the kidney had been flushed at 5 °C with a mixture of dextran and diluted blood prior to storage. In 1960 Lapchinsky confirmed that similar storage periods were possible, when he reported eight dogs surviving after their kidneys had been stored at 2-4 °C for 28 hours, followed by auto-transplantation and delayed contralateral nephrectomy. Although Lapchinsky gave no details in his paper, Humphries reported that these experiments had involved cooling the kidneys for 1 hour with cold blood, and then storage at 2-4 °C, followed by rewarming of the kidneys over 1 hour with warm blood at the time of reimplantation. The contralateral nephrectomies were delayed for two months.
Humphries developed this storage technique by continuously perfusing the kidney throughout the period of storage. He used diluted plasma or serum as the perfusate and pointed out the necessity for low perfusate pressures to prevent kidney swelling, but admitted that the optimum values for such variables as perfusate temperature, Po, and flow, remained unknown. His best results, at this time, were 2 dogs that survived after having their kidneys stored for 24 hours at 4-10 °C followed by auto-transplantation and delayed contralateral nephrectomy a few weeks later.
Calne challenged the necessity of using continuous perfusion methods by demonstrating that successful 12-hour preservation could be achieved using much simpler techniques. Calne had one kidney supporting life even when the contralateral nephrectomy was performed at the same time as the reimplantation operation. Calne merely heparinised dog kidneys and then stored them in iced solution at 4 °C. Although 17-hour preservation was shown to be possible in one experiment when nephrectomy was delayed, no success was achieved with 24-hour storage.
The next advance was made by Humphries in 1964, when he modified the perfusate used in his original continuous perfusion system, and had a dog kidney able to support life after 24-hour storage, even when an immediate contralateral nephrectomy was performed at the same time as the reimplantation. In these experiments autogenous blood, diluted 50% with Tis-U-Sol solution at 10 °C, was used as the perfusate. The perfusate pressure was 40 mm Hg and perfusate pH 7.11-7.35 (at 37 °C). A membrane lung was used for oxygenation to avoid damaging the blood.
In attempting to improve on these results Manax investigated the effect of hyperbaric oxygen, and found that successful 48-hour storage of dog kidneys was possible at 2 °C without using continuous perfusion, when the kidneys were flushed with a dextran/Tis-U-Sol solution before storage at 7.9 atmospheres pressure, and if the contralateral nephrectomy was delayed till 2 to 4 weeks after reimplantation. Manax postulated that hyperbaric oxygen might work either by inhibiting metabolism or by aiding diffusion of oxygen into the kidney cells, but he reported no control experiments to determine whether other aspects of his model were more important than hyperbaria.
A marked improvement in storage times was achieved by Belzer in 1967 when he reported successful 72-hour kidney storage after returning to the use of continuous perfusion using a canine plasma based perfusate at 8-12 °C. Belzer found that the crucial factor in permitting uncomplicated 72-hour perfusion was cryoprecipitation of the plasma used in the perfusate to reduce the amount of unstable lipo-proteins which otherwise precipitated out of solution and progressively obstructed the kidney's vascular system. A membrane oxygenator was also used in the system in a further attempt to prevent denaturation of the lipo-proteins because only 35% of the lipo-proteins were removed by cryo-precipitation. The perfusate comprised 1 litre of canine plasma, 4 mEq of magnesium sulphate, 250 mL of dextrose, 80 units of insulin, 200,000 units of penicillin and 100 mg of hydrocortisone. Besides being cryo-precipitated, the perfusate was pre-filtered through a 0.22 micron filter immediately prior to use. Belzer used a perfusate pH of 7.4-7.5, a Po of 150–190 mm Hg, and a perfusate pressure of 50–80 mm Hg systolic, in a machine that produced a pulsatile perfusate flow. Using this system Belzer had 6 dogs surviving after their kidneys had been stored for 72 hours and then reimplanted, with immediate contralateral nephrectomies being performed at the reimplantation operations.
Belzers use of hydrocortisone as an adjuvant to preservation had been suggested by Lotkes work with dog kidney slices, in which hydrocortisone improved the ability of slices to excrete PAH and oxygen after 30 hour storage at 2-4 °C; Lotke suggested that hydrocortisone might be acting as a lysosomal membrane stabiliser in these experiments. The other components of Belzers model were arrived at empirically. The insulin and magnesium were used partially in an attempt to induce artificial hibernation, as Suomalainen found this regime to be effective in inducing hibernation in natural hibernators. The magnesium was also provided as a metabolic inhibitor following Kamiyamas demonstration that it was an effective agent in dog heart preservation. A further justification for the magnesium was that it was needed to replace calcium which had been bound by citrate in the plasma.
Belzer demonstrated the applicability of his dog experiments to human kidney storage when he reported his experiences in human renal transplantation using the same storage techniques as he had used for dog kidneys. He was able to store kidneys for up to 50 hours with only 8% of patients requiring post operative dialysis when the donor had been well prepared.
In 1968 Humphries reported 1 survivor out of 14 dogs following 5 day storage of their kidneys in a perfusion machine at 10 °C, using a diluted plasma medium containing extra fatty acids. However, delayed contralateral nephrectomy 4 weeks after reimplantation was necessary in these experiments to achieve success, and this indicated that the kidneys were severely injured during storage.
In 1969 Collins reported an improvement in the results that could be achieved with simple non perfusion methods of hypothermic kidney storage. He based his technique on the observation by Keller that the loss of electrolytes from a kidney during storage could be prevented by the use of a storage fluid containing cations in quantities approaching those normally present in cells. In Collins model, the dogs were well hydrated prior to nephrectomy, and were also given mannitol to induce a diuresis. Phenoxybenzamine, a vasodilator and lysozomal enzyme stabiliser, was injected into the renal artery before nephrectomy. The kidneys were immersed in saline immediately after removal, and perfused through the renal artery with 100-150 mL of a cold electrolyte solution from a height of 100 cm. The kidneys remained in iced saline for the rest of the storage period. The solution used for these successful cold perfusions imitated the electrolyte composition of intracellular fluids by containing large amounts of potassium and magnesium. The solution also contained glucose, heparin, procaine and phenoxybenzamine. The solutions pH was 7.0 at 25 °C. Collins was able to achieve successful 24-hour storage of 6 kidneys, and 30 hour storage of 3 kidneys, with the kidneys functioning immediately after reimplantation, despite immediate contralateral nephrectomies. Collins emphasised the poor results obtained with a Ringers solution flush, in finding similar results with this management when compared with kidneys treated by surface cooling alone. Liu reported that Collins solution could give successful 48-hour storage when the solution was modified by the inclusion of amino acids and vitamins. However, Liu performed no control experiments to show that these modifications were crucial.
Difficulty was found by other workers in repeating Belzers successful 72-hour perfusion storage experiments. Woods was able to achieve successful 48-hour storage of 3 out of 6 kidneys when he used the Belzer additives with cryoprecipitated plasma as the perfusate in a hypothermic perfusion system, but he was unable to extend the storage time to 72 hours as Belzer had done. However, Woods later achieved successful 3 and 7 days storage of dog kidneys. Woods had modified Belzers perfusate by the addition of 250 mg of methyl prednisolone, increased the magnesium sulphate content to 16.2 mEq and the insulin to 320 units. Six of 6 kidneys produced life sustaining function when they were reimplanted after 72 hours storage despite immediate contralateral nephrectomies; 1 of 2 kidneys produced life sustaining function after 96 hours storage, 1 of 2 after 120 hours storage, and 1 of 2 after 168 hours storage. Perfusate pressure was 60 mm Hg with a perfusate pump rate of 70 beats per minute, and perfusate pH was automatically maintained at 7.4 by a CO titrator. Woods stressed the importance of hydration of the donor and recipient animals. Without the methyl prednisolone, Woods found vessel fragility to be a problem when storage times were longer than 48 hours.
A major simplification to the techniques of hypothermic perfusion storage was made by Johnson and Claes in 1972 with the introduction of an albumin based perfusate. This perfusate eliminated the need for the manufacture of the cryoprecipitated and millipore filtered plasma used by Belzer. The preparation of this perfusate had been laborious and time-consuming, and there was the potential risk from hepatitis virus and cytotoxic antibodies. The absence of lipo-proteins from the perfusate meant that the membrane oxygenator could be eliminated from the perfusion circuit, as there was no need to avoid a perfusate/air interface to prevent precipitation of lipo-proteins. Both workers used the same additives as recommended by Belzer.
The solution that Johnson used was prepared by the Blood Products Laboratory (Elstree: England) by extracting heat labile fibrinogen and gamma globulins from plasma to give a plasma protein fraction (PPF) solution. The solution was incubated at 60 °C for 10 hours to inactivate the agent of serum hepatitis. The result was a 45 g/L human albumin solution containing small amounts of gamma and beta globulins which was stable between 0 °C and 30 °C for 5 years. PPF contained 2.2 mmol/L of free fatty acids.
Johnsons experiments were mainly concerned with the storage of kidneys that had been damaged by prolonged warm injury. However, in a control group of non-warm injured dog kidneys, Johnson showed that 24-hour preservation was easily achieved when using a PPF perfusate, and he described elsewhere a survivor after 72 hours perfusion and reimplantation with immediate contralateral nephrectomy. With warm injured kidneys, PPF perfusion gave better results than Collins method, with 6 out of 6 dogs surviving after 40 minutes warm injury and 24-hour storage followed by reimplantation of the kidneys and immediate contralateral nephrectomy. Potassium, magnesium, insulin, glucose, hydrocortisone and ampicillin were added to the PPF solution to provide an energy source and to prevent leakage of intracellular potassium. Perfusate temperature was 6 °C, pressure 40–80 mm Hg, and Po 200–400 mm Hg. The pH was maintained between 7.2 and 7.4.
Claes used a perfusate based on human albumin (Kabi: Sweden) diluted with saline to a concentration of 45 g/L. Claes preserved 4 out of 5 dog kidneys for 96 hours with the kidneys functioning immediately after reimplantation despite immediate contralateral nephrectomies. Claes also compared this perfusate with Belzer's cryoprecipitated plasma in a control group and found no significant difference between the function of the reimplanted kidneys in the two groups.
The only other group besides Woods' to report successful seven-day storage of kidneys was Liu and Humphries in 1973. They had three out of seven dogs surviving, after their kidneys had been stored for seven days followed by reimplantation and immediate contralateral nephrectomy. Their best dog had a peak post reimplantation creatinine of 50 mg/L (0.44 mmol/L). Liu used well hydrated dogs undergoing a mannitol diuresis and stored the kidneys at 9 °C – 10 °C using a perfusate derived from human PPF. The PPF was further fractionated by using a highly water-soluble polymer (Pluronic F-38), and sodium acetyl tryptophanate and sodium caprylate were added to the PPF as stabilisers to permit pasteurisation. To this solution were added human albumin, heparin, mannitol, glucose, magnesium sulphate, potassium chloride, insulin, methyl prednisolone, carbenicillin, and water to adjust the osmolality to 300-310 mosmol/kg. The perfusate was exchanged after 3.5 days storage. Perfusate pressure was 60 mm Hg or less, at a pump rate of 60 per minute. Perfusate pH was 7.12–7.32 (at 37 °C), Pco2 27–47 mm Hg, and Po 173–219 mm Hg. In a further report on this study Humphries found that when the experiments were repeated with a new batch of PPF no survivors were obtained, and histology of the survivors from the original experiment showed glomerular hypercellularity which he attributed to a possible toxic effect of the Pluronic polymer.
Joyce and Proctor reported the successful use of a simple dextran based perfusate for 72-hour storage of dog kidneys. 10 out of 17 kidneys were viable after reimplantation and immediate contralateral nephrectomy. Joyce used non pulsatile perfusion at 4 °C with a perfusate containing Dextran 70 (Pharmacia) 2.1%, with additional electrolytes, glucose (19.5 g/L), procaine and hydrocortisone. The perfusate contained no plasma or plasma components. Perfusate pressure was only 30 cm HO, pH 7.34-7.40 and Po 250–400 mm Hg. This work showed that, for 72-hour storage, no nutrients other than glucose were needed, and low perfusate pressures and flows were adequate.
In 1973 Sacks showed that simple ice storage could be successfully used for 72-hour storage when a new flushing solution was used for the initial cooling and flush out of the kidney. Sacks removed kidneys from well hydrated dogs that were diuresing after a mannitol infusion, and flushed the kidneys with 200 mL of solution from a height of 100 cm. The kidneys were then simply kept at 2 °C for 72 hours without further perfusion. Reimplantation was followed by immediate contralateral nephrectomies. The flush solution was designed to imitate intracellular fluid composition and contained mannitol as an impermeable ion to further prevent cell swelling. The osmolality of the solution was 430 mosmol/kg and its pH was 7.0 at 2 °C. The additives that had been used by Collins (dextrose, phenoxybenzamine, procaine and heparin) were omitted by Sacks.
These results have been equalled by Ross who also achieved successful 72-hour storage without using continuous perfusion, although he was unable to reproduce Collins or Sacks results using the original Collins or Sacks solutions. Rosss successful solution was similar in electrolyte composition to intracellular fluid with the addition of hypertonic citrate and mannitol. No phosphate, bicarbonate, chloride or glucose were present in the solution; the osmolality was 400 mosmol/kg and the pH 7.1. Five of 8 dogs survived reimplantation of their kidneys and immediate contralateral nephrectomy, when the kidneys had been stored for 72 hours after having been flushed with Rosss solution; but Ross was unable to achieve 7 day storage with this technique even when delayed contralateral nephrectomy was used.
The requirements for successful 72-hour hypothermic perfusion storage have been further defined by Collins who showed that pulsatile perfusion was not needed if a perfusate pressure of 49 mm Hg was used, and that 7 °C was a better temperature for storage than 2 °C or 12 °C. He also compared various perfusate compositions and found that a phosphate buffered perfusate could be used successfully, so eliminating the need for a carbon dioxide supply. Grundmann has also shown that low perfusate pressure is adequate. He used a mean pulsatile pressure of 20 mm Hg in 72-hour perfusions and found that this gave better results than mean pressures of 15, 40, 50 or 60 mm Hg.
Successful storage up to 8 days was reported by Cohen using various types of perfusate – with the best result being obtained when using a phosphate buffered perfusate at 8 °C. Inability to repeat these successful experiments was thought to be due to changes that had been made in the way that the PPF was manufactured with higher octanoic acid content being detrimental. Octanoic acid was shown to be able to stimulate metabolic activity during hypothermic perfusion and this might be detrimental. | 1 | Cryobiology |
Multiple tokamaks are currently under construction with the goal of becoming the first magnetically confined burning plasma experiment.
ITER, being built near Cadarache in France, has the stated goal of allowing fusion scientists and engineers to investigate the physics, engineering, and technologies associated with a self-heating plasma. Issues to be explored include understanding and controlling a strongly coupled, self-organized plasma; management of heat and particles that reach plasma-facing surfaces; demonstration of fuel breeding technology; and the physics of energetic particles. These issues are relevant to ITER's broader goal of using self-heating plasma reactions to become the first fusion energy device that produces more power than it consumes, a major step toward commercial fusion power production. To reach fusion-relevant temperatures, the ITER tokamak will heat plasmas using three methods: ohmic heating (running electric current through the plasma), neutral particle beam injection, and high-frequency electromagnetic radiation.
SPARC, being built in Devens in the United States, plans to verify the technology and physics required to build a power plant based on the ARC fusion power plant concept. SPARC is designed to achieve this with margin in excess of breakeven and may be capable of achieving up to 140 MW of fusion power for 10-second bursts despite its relatively compact size. SPARC's high-temperature superconductor magnet is intended to create much stronger magnetic fields, allowing it to be much smaller than similar tokamaks. | 3 | Nuclear Fusion |
Many phosphors tend to lose efficiency gradually by several mechanisms. The activators can undergo change of valence (usually oxidation), the crystal lattice degrades, atoms – often the activators – diffuse through the material, the surface undergoes chemical reactions with the environment with consequent loss of efficiency or buildup of a layer absorbing either the exciting or the radiated energy, etc.
The degradation of electroluminescent devices depends on frequency of driving current, the luminance level, and temperature; moisture impairs phosphor lifetime very noticeably as well.
Harder, high-melting, water-insoluble materials display lower tendency to lose luminescence under operation.
Examples:
* BaMgAlO:Eu (BAM), a plasma-display phosphor, undergoes oxidation of the dopant during baking. Three mechanisms are involved; absorption of oxygen atoms into oxygen vacancies on the crystal surface, diffusion of Eu(II) along the conductive layer, and electron transfer from Eu(II) to absorbed oxygen atoms, leading to formation of Eu(III) with corresponding loss of emissivity. Thin coating of aluminium phosphate or lanthanum(III) phosphate is effective in creating a barrier layer blocking access of oxygen to the BAM phosphor, for the cost of reduction of phosphor efficiency. Addition of hydrogen, acting as a reducing agent, to argon in the plasma displays significantly extends the lifetime of BAM:Eu phosphor, by reducing the Eu(III) atoms back to Eu(II).
* YO:Eu phosphors under electron bombardment in presence of oxygen form a non-phosphorescent layer on the surface, where electron–hole pairs recombine nonradiatively via surface states.
* ZnS:Mn, used in AC thin-film electroluminescent (ACTFEL) devices degrades mainly due to formation of deep-level traps, by reaction of water molecules with the dopant; the traps act as centers for nonradiative recombination. The traps also damage the crystal lattice. Phosphor aging leads to decreased brightness and elevated threshold voltage.
* ZnS-based phosphors in CRTs and FEDs degrade by surface excitation, coulombic damage, build-up of electric charge, and thermal quenching. Electron-stimulated reactions of the surface are directly correlated to loss of brightness. The electrons dissociate impurities in the environment, the reactive oxygen species then attack the surface and form carbon monoxide and carbon dioxide with traces of carbon, and nonradiative zinc oxide and zinc sulfate on the surface; the reactive hydrogen removes sulfur from the surface as hydrogen sulfide, forming nonradiative layer of metallic zinc. Sulfur can be also removed as sulfur oxides.
* ZnS and CdS phosphors degrade by reduction of the metal ions by captured electrons. The M ions are reduced to M; two M then exchange an electron and become one M and one neutral M atom. The reduced metal can be observed as a visible darkening of the phosphor layer. The darkening (and the brightness loss) is proportional to the phosphor's exposure to electrons and can be observed on some CRT screens that displayed the same image (e.g. a terminal login screen) for prolonged periods.
* Europium(II)-doped alkaline earth aluminates degrade by formation of color centers.
* :Ce degrades by loss of luminescent Ce ions.
* :Mn (P1) degrades by desorption of oxygen under electron bombardment.
* Oxide phosphors can degrade rapidly in presence of fluoride ions, remaining from incomplete removal of flux from phosphor synthesis.
* Loosely packed phosphors, e.g. when an excess of silica gel (formed from the potassium silicate binder) is present, have tendency to locally overheat due to poor thermal conductivity. E.g. :Tb is subject to accelerated degradation at higher temperatures. | 0 | Luminescence |
An ova bank, or cryobank, or egg cell bank is a facility that collects and stores human ova, mainly from ova donors, primarily for the purpose of achieving pregnancies of either the donor, at a later time (i.e. to overcome issues of infertility), or through third party reproduction, notably by artificial insemination. Ova donated in this way are known as donor ova. | 1 | Cryobiology |
The use of monoclonal antibodies for therapy is now widespread for treatment of cancers and inflammatory diseases. Using cellulose sulphate technology, scientists have successfully encapsulated antibody producing hybridoma cells and demonstrated subsequent release of the therapeutic antibody from the capsules. The capsules containing the hybridoma cells were used in pre-clinical studies to deliver neutralising antibodies to the mouse retrovirus FrCasE, successfully preventing disease. | 2 | Tissue Engineering |
In glow sticks, phenol is produced as a byproduct. It is advisable to keep the mixture away from skin and to prevent accidental ingestion if the glow stick case splits or breaks. If spilled on skin, the chemicals could cause slight skin irritation, swelling, or, in extreme circumstances, vomiting and nausea. Some of the chemicals used in older glow sticks were thought to be potential carcinogens. The sensitizers used are polynuclear aromatic hydrocarbons, a class of compounds known for their carcinogenic properties.
Dibutyl phthalate, a plasticizer sometimes used in glow sticks (and many plastics), has raised some health concerns. It was put on California's list of suspected teratogens in 2006. Glow stick liquid contains ingredients that can act as a plasticizer, softening plastics onto which it leaks. Diphenyl oxalate can sting and burn eyes, irritate and sting skin and can burn the mouth and throat if ingested.
Researchers in Brazil, concerned about waste from glowsticks used in fishing in their country, published a study in 2014 on this topic. It measured the secondary reactions that continue within used glow sticks, toxicity to cells in culture, and chemical reactions with DNA in vitro. The authors found "high toxicity" of light stick solutions, and evidence of reactivity with DNA. They concluded that light stick solutions "are hazardous and that the health risks associated with exposure have not yet been properly evaluated." | 0 | Luminescence |
IVF may be used to overcome female infertility when it is due to problems with the fallopian tubes, making in vivo fertilisation difficult. It can also assist in male infertility, in those cases where there is a defect in sperm quality; in such situations intracytoplasmic sperm injection (ICSI) may be used, where a sperm cell is injected directly into the egg cell. This is used when sperm has difficulty penetrating the egg. ICSI is also used when sperm numbers are very low. When indicated, the use of ICSI has been found to increase the success rates of IVF.
According to UK's National Institute for Health and Care Excellence (NICE) guidelines, IVF treatment is appropriate in cases of unexplained infertility for people who have not conceived after 2 years of regular unprotected sexual intercourse.
In people with anovulation, it may be an alternative after 7–12 attempted cycles of ovulation induction, since the latter is expensive and more easy to control. | 1 | Cryobiology |
A size range coefficient of approximately three is advisable. A minimum amount of undersized fine material must enter the machines to optimize availability. Moisture of the feed is not important, if the material is sufficiently dewatered and the undersize fraction is efficiently removed. For surface detection technologies sometimes spray water on the classifying screen is required to clean the surfaces. Surface detection technologies would otherwise measure the reflectance of the adhesions on the surface and a correlation to the particle's content is not given. | 5 | Separation Processes |
* Centrifugation and cyclonic separation, separates based on density differences
* Chelation
* Chromatography separates dissolved substances by different interaction with (i.e., travel through) a material.
** High-performance liquid chromatography (HPLC)
** Thin-layer chromatography (TLC)
** Countercurrent chromatography (CCC)
** Droplet countercurrent chromatography (DCC)
** Paper chromatography
** Ion chromatography
** Size-exclusion chromatography (SEC)
** Affinity chromatography
** Centrifugal partition chromatography
** Gas chromatography and Inverse gas chromatography
* Crystallization
* Decantation
* Demister (vapor), removes liquid droplets from gas streams
* Distillation, used for mixtures of liquids with different boiling points
* Drying, removes liquid from a solid by vaporization or evaporation
* Electrophoresis, separates organic molecules based on their different interaction with a gel under an electric potential (i.e., different travel)
** Capillary electrophoresis
* Electrostatic separation, works on the principle of corona discharge, where two plates are placed close together and high voltage is applied. This high voltage is used to separate the ionized particles.
* Elutriation
* Evaporation
* Extraction
** Leaching
** Liquid–liquid extraction
** Solid phase extraction
** Supercritical fluid extraction
** Subcritical fluid extraction
* Field flow fractionation
* Filtration – Mesh, bag and paper filters are used to remove large particulates suspended in fluids (e.g., fly ash) while membrane processes including microfiltration, ultrafiltration, nanofiltration, reverse osmosis, dialysis (biochemistry) utilising synthetic membranes, separates micrometre-sized or smaller species
* Flocculation, separates a solid from a liquid in a colloid, by use of a flocculant, which promotes the solid clumping into flocs
* Fractional distillation
* Fractional freezing
* Magnetic separation
* Oil-water separation, gravimetrically separates suspended oil droplets from waste water in oil refineries, petrochemical and chemical plants, natural gas processing plants and similar industries
* Precipitation
* Recrystallization
* Scrubbing, separation of particulates (solids) or gases from a gas stream using liquid.
* Sedimentation, separates using vocal density pressure differences
** Gravity separation
* Sieving
* Sponge, adhesion of atoms, ions or molecules of gas, liquid, or dissolved solids to a surface
* Stripping
* Sublimation
* Vapor–liquid separation, separates by gravity, based on the Souders–Brown equation
* Winnowing
* Zone refining | 5 | Separation Processes |
Cryobiology is the study of living organisms, organs, biological tissues or biological cells at low temperatures. This knowledge is practically applied in three fields: cryonics, cryopreservation and cryosurgery. Please see cryobiology for more information. The Wikipedia entries related to cryobiology have typically been miscategorized as cryogenics, and the same mistake has been made for cryonics. | 1 | Cryobiology |
** HIBALL study by German and US institutions, Garching uses the high repetition rate of the RF accelerator driver to serve four reactor chambers and first-wall protection using liquid lithium inside the chamber cavity.
** Tore Supra construction starts at Cadarache, France. Its superconducting magnets will permit it to generate a strong permanent toroidal magnetic field.
** high-confinement mode (H-mode) discovered in tokamaks.
** JET, the largest operational magnetic confinement plasma physics experiment is completed on time and on budget. First plasmas achieved.
** The NOVETTE laser at LLNL comes on line and is used as a test bed for the next generation of ICF lasers, specifically the NOVA laser.
** The huge 10 beam NOVA laser at LLNL is completed and switches on in December. NOVA would ultimately produce a maximum of 120 kilojoules of infrared laser light during a nanosecond pulse in a 1989 experiment.
** National Academy of Sciences reviewed military ICF programs, noting HIF's major advantages clearly but averring that HIF was "supported primarily by other [than military] programs". The review of ICF by the National Academy of Sciences marked the trend with the observation: "The energy crisis is dormant for the time being." Energy becomes the sole purpose of heavy ion fusion.
** The Japanese tokamak, JT-60 completed. First plasmas achieved.
** The T-15, Soviet tokamak with superconducting helium-cooled coils completed.
** The Conceptual Design Activity for the International Thermonuclear Experimental Reactor (ITER), the successor to T-15, TFTR, JET and JT-60, begins. Participants include EURATOM, Japan, the Soviet Union and United States. It ended in 1990.
** The first plasma produced at Tore Supra in April.
** On March 23, two Utah electrochemists, Stanley Pons and Martin Fleischmann, announced that they had achieved cold fusion: fusion reactions which could occur at room temperatures. However, they made their announcements before any peer review of their work was performed, and no subsequent experiments by other researchers revealed any evidence of fusion. | 3 | Nuclear Fusion |
It is also used to illuminate pictures painted with fluorescent colors, particularly on black velvet, which intensifies the illusion of self-illumination. The use of such materials, often in the form of tiles viewed in a sensory room under UV light, is common in the United Kingdom for the education of students with profound and multiple learning difficulties. Such fluorescence from certain textile fibers, especially those bearing optical brightener residues, can also be used for recreational effect, as seen, for example, in the opening credits of the James Bond film A View to a Kill. Black light puppetry is also performed in a black light theater. | 8 | Ultraviolet Radiation |
In artificial fusion, the primary fuel is not constrained to be protons and higher temperatures can be used, so reactions with larger cross-sections are chosen. Another concern is the production of neutrons, which activate the reactor structure radiologically, but also have the advantages of allowing volumetric extraction of the fusion energy and tritium breeding. Reactions that release no neutrons are referred to as aneutronic.
To be a useful energy source, a fusion reaction must satisfy several criteria. It must:
;Be exothermic: This limits the reactants to the low Z (number of protons) side of the curve of binding energy. It also makes helium the most common product because of its extraordinarily tight binding, although and also show up.
;Involve low atomic number (Z) nuclei: This is because the electrostatic repulsion that must be overcome before the nuclei are close enough to fuse ( Coulomb barrier ) is directly related to the number of protons it contains – its atomic number.
;Have two reactants: At anything less than stellar densities, three-body collisions are too improbable. In inertial confinement, both stellar densities and temperatures are exceeded to compensate for the shortcomings of the third parameter of the Lawson criterion, ICF's very short confinement time.
;Have two or more products: This allows simultaneous conservation of energy and momentum without relying on the electromagnetic force.
;Conserve both protons and neutrons: The cross sections for the weak interaction are too small.
Few reactions meet these criteria. The following are those with the largest cross sections:
For reactions with two products, the energy is divided between them in inverse proportion to their masses, as shown. In most reactions with three products, the distribution of energy varies. For reactions that can result in more than one set of products, the branching ratios are given.
Some reaction candidates can be eliminated at once. The D–Li reaction has no advantage compared to p– because it is roughly as difficult to burn but produces substantially more neutrons through – side reactions. There is also a p– reaction, but the cross section is far too low, except possibly when T > 1 MeV, but at such high temperatures an endothermic, direct neutron-producing reaction also becomes very significant. Finally there is also a p– reaction, which is not only difficult to burn, but can be easily induced to split into two alpha particles and a neutron.
In addition to the fusion reactions, the following reactions with neutrons are important in order to "breed" tritium in "dry" fusion bombs and some proposed fusion reactors:
The latter of the two equations was unknown when the U.S. conducted the Castle Bravo fusion bomb test in 1954. Being just the second fusion bomb ever tested (and the first to use lithium), the designers of the Castle Bravo "Shrimp" had understood the usefulness of Li in tritium production, but had failed to recognize that Li fission would greatly increase the yield of the bomb. While Li has a small neutron cross-section for low neutron energies, it has a higher cross section above 5 MeV. The 15 Mt yield was 150% greater than the predicted 6 Mt and caused unexpected exposure to fallout.
To evaluate the usefulness of these reactions, in addition to the reactants, the products, and the energy released, one needs to know something about the nuclear cross section. Any given fusion device has a maximum plasma pressure it can sustain, and an economical device would always operate near this maximum. Given this pressure, the largest fusion output is obtained when the temperature is chosen so that is a maximum. This is also the temperature at which the value of the triple product required for ignition is a minimum, since that required value is inversely proportional to (see Lawson criterion). (A plasma is "ignited" if the fusion reactions produce enough power to maintain the temperature without external heating.) This optimum temperature and the value of at that temperature is given for a few of these reactions in the following table.
Note that many of the reactions form chains. For instance, a reactor fueled with and creates some , which is then possible to use in the – reaction if the energies are "right". An elegant idea is to combine the reactions (8) and (9). The from reaction (8) can react with in reaction (9) before completely thermalizing. This produces an energetic proton, which in turn undergoes reaction (8) before thermalizing. Detailed analysis shows that this idea would not work well, but it is a good example of a case where the usual assumption of a Maxwellian plasma is not appropriate. | 3 | Nuclear Fusion |
Growing crystals for X-ray crystallography can be quite difficult. For X-ray analysis, single perfect crystals are required. Typically a small amount (5–100 mg) of a pure compound is used, and crystals are allowed to grow very slowly. Several techniques can be used to grow these perfect crystals:
* Slow evaporation of a single solvent - typically the compound is dissolved in a suitable solvent and the solvent is allowed to slowly evaporate. Once the solution is saturated crystals can be formed.
* Slow evaporation of a multi-solvent system - the same as above, however as the solvent composition changes due to evaporation of the more volatile solvent. The compound is more soluble in the volatile solvent, and so the compound becomes increasingly insoluble in solution and crystallizes.
* Slow diffusion - similar to the above. However, a second solvent is allowed to evaporate from one container into a container holding the compound solution (gas diffusion). As the solvent composition changes due to an increase in the solvent that has gas diffused into the solution, the compound becomes increasingly insoluble in the solution and crystallizes.
* Interface/slow mixing (often performed in an NMR tube). Similar to the above, but instead of one solvent gas-diffusing into another, the two solvents mix (diffuse) by liquid-liquid diffusion. Typically a second solvent is "layered" carefully on top of the solution containing the compound. Over time the two solution mix. As the solvent composition changes due to diffusion, the compound becomes increasingly insoluble in solution and crystallizes, usually at the interface. Additionally, it is better to use a denser solvent as the lower layer, and/or a hotter solvent as the upper layer because this results in the slower mixing of the solvents.
* Specialized equipment can be used in the shape of an "H" to perform the above, where one of the vertical lines of the "H" is a tube containing a solution of the compound, and the other vertical line of the "H" is a tube containing a solvent which the compound is not soluble in, and the horizontal line of the "H" is a tube which joins the two vertical tubes, which also has a fine glass sinter that restricts the mixing of the two solvents.
* Once single perfect crystals have been obtained, it is recommended that the crystals are kept in a sealed vessel with some of the liquid of crystallization to prevent the crystal from drying out. Single perfect crystals may contain solvent of crystallization in the crystal lattice. Loss of this internal solvent from the crystals can result in the crystal lattice breaking down, and the crystals turning to powder. | 5 | Separation Processes |
Most prominent example of the application of sensor-based ore sorting is the rejection of barren waste before transporting and comminution. Waste rejection is also known under the term pre-concentration. A discrimination has been introduced by Robben. Rule of thumb is that at least 25% of liberated barren waste must be present in the fraction to be treated by sensor-based ore sorting to make waste rejection financially feasible.
Reduction of waste before it enters comminution and grinding processes does not only reduce the costs in those processes, but also releases the capacity that can be filled with higher grade material and thus implies higher productivity of the system. A prejudice against the application of a waste rejection process is, that the valuable content lost in this process is a penalty higher than the savings that can be achieved. But it is reported in the literature that the overall recovery even increases through bringing higher grade material as feed into the mill. In addition, the higher productivity is an additional source of income. If noxious waste such as acid consuming calcite is removed, the downstream recovery increases and the downstream costs decrease disproportionally as reported for example by Bergmann. The coarse waste rejected can be an additional source of income if there is a local market for aggregates. | 5 | Separation Processes |
An organoid is a miniaturised and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural and biological complexity of that organ. They are derived from one or a few cells from a tissue, embryonic stem cells or induced pluripotent stem cells, which can self-organize in three-dimensional culture owing to their self-renewal and differentiation capacities. The technique for growing organoids has rapidly improved since the early 2010s, and The Scientist names it as one of the biggest scientific advancements of 2013. Scientists and engineers use organoids to study development and disease in the laboratory, drug discovery and development in industry, personalized diagnostics and medicine, gene and cell therapies, tissue engineering and regenerative medicine. | 2 | Tissue Engineering |
Radioluminescence is the phenomenon by which light is produced in a material by bombardment with ionizing radiation such as alpha particles, beta particles, or gamma rays. Radioluminescence is used as a low level light source for night illumination of instruments or signage. Radioluminescent paint is occasionally used for clock hands and instrument dials, enabling them to be read in the dark. Radioluminescence is also sometimes seen around high-power radiation sources, such as nuclear reactors and radioisotopes. | 0 | Luminescence |
Its most advanced candidate is the Neo-Urinary Conduit. A Phase I clinical trial of the Tengion Neo-Urinary Conduit was completed in some health care institutions, in patients with bladder cancer who require a total cystectomy. The trial ended in December 2014, however information on the results has not yet been made publicly available.
The company also develops the Neo-Bladder Augment, a Phase II clinical trial product for the treatment of neurogenic bladder resulting from spina bifida in pediatric patients, as well as neurogenic bladder resulting from spinal cord injury in adult patients; the Neo-Bladder Replacement to serve as a functioning bladder, eliminating the need for an ostomy bag, for patients who have their bladders removed due to cancer; and the Neo-Kidney Augment to prevent or delay dialysis by increasing renal function in patients with advanced chronic kidney disease. | 2 | Tissue Engineering |
In the early phase of drug development, animal models were the only way of obtaining in vivo data that would predict the human pharmacokinetic responses. However, experiments on animals are lengthy, expensive and controversial. For example, animal models are often subjected to mechanical or chemical techniques that simulate human injuries. There are also concerns with regards to the validity of such animal models, due to deficiency in cross-species extrapolation. Moreover, animal models offer very limited control of individual variables and it can be cumbersome to harvest specific information.
Therefore, mimicking a human's physiological responses in an in vitro model needs to be made more affordable, and needs to offer cellular level control in biological experiments: biomimetic microfluidic systems could replace animal testing. The development of MEMS-based biochips that reproduce complex organ-level pathological responses could revolutionize many fields, including toxicology and the developmental process of pharmaceuticals and cosmetics that rely on animal testing and clinical trials.
Recently, physiologically based perfusion in vitro systems have been developed to provide cell culture environment close to in vivo cell environment. A new testing platforms based on multi-compartmental perfused systems have gained a remarkable interest in pharmacology and toxicology. It aims to provide a cell culture environment close to the in vivo situation to reproduce more reliably in vivo mechanisms or ADME processes that involve its absorption, distribution, metabolism, and elimination. Perfused in vitro systems combined with kinetic modelling are promising tools for studying in vitro the different processes involved in the toxicokinetics of xenobiotics.
Efforts made toward the development of micro fabricated cell culture systems that aim to create models that replicate aspects of the human body as closely as possible and give examples that demonstrate their potential use in drug development, such as identifying synergistic drug interactions as well as simulating multi-organ metabolic interactions. Multi compartment micro fluidic-based devices, particularly those that are physical representations of physiologically based pharmacokinetic (PBPK) models that represent the mass transfer of compounds in compartmental models of the mammalian body, may contribute to improving the drug development process. Some emerging technologies have the ability to measure multiple biological processes in a co-culture of mixed cell types, cells from different parts of the body, which is suggested to provide more similarity to in Vivo models.
Mathematical pharmacokinetic (PK) models aim to estimate concentration-time profiles within each organ on the basis of the initial drug dose. Such mathematical models can be relatively simple, treating the body as a single compartment in which the drug distribution reaches a rapid equilibrium after administration. Mathematical models can be highly accurate when all parameters involved are known. Models that combine PK or PBPK models with PD models can predict the time-dependent pharmacological effects of a drug. We can nowadays predict with PBPK models the PK of about any chemical in humans, almost from first principles. These models can be either very simple, like statistical dose-response models, or sophisticated and based on systems biology, according to the goal pursued and the data available. All we need for those models are good parameter values for the molecule of interest.
Microfluidic cell culture systems such as micro cell culture analogs (μCCAs) could be used in conjunction with PBPK models. These μCCAs scaled-down devices, termed also body-on-a-chip devices, can simulate multi-tissue interactions under near-physiological fluid flow conditions and with realistic tissue-to-tissue size ratios . Data obtained with these systems may be used to test and refine mechanistic hypotheses. Microfabricating devices also allows us to custom-design them and scale the organs' compartments correctly with respect to one another.
Because the device can be used with both animal and human cells, it can facilitate cross-species extrapolation. Used in conjunction with PBPK models, the devices permit an estimation of effective concentrations that can be used for studies with animal models or predict the human response. In the development of multicompartment devices, representations of the human body such as those in used PBPK models can be used to guide the device design with regard to the arrangement of chambers and fluidic channel connections to augment the drug development process, resulting in increased success in clinical trials. | 2 | Tissue Engineering |