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For clarification, a distinction between the two corresponding cases is needed. With reference to a phase diagram, the sublimation that occurs left of the solid-gas boundary, the triple point or the solid-liquid boundary (corresponding to evaporation in vaporization) may be called gradual sublimation; and the substance sublimes gradually, regardless of rate. The sublimation that occurs at the solid-gas boundary (critical sublimation point) (corresponding to boiling in vaporization) may be called rapid sublimation, and the substance sublimes rapidly. The words "gradual" and "rapid" have acquired special meanings in this context and no longer describe the rate of sublimation. | 5 | Separation Processes |
Settling basins and clarifiers are designed to retain water so that suspended solids can settle. By sedimentation principles, the suitable treatment technologies should be chosen depending on the specific gravity, size and shear resistance of particles. Depending on the size and density of particles, and physical properties of the solids, there are four types of sedimentation processes:
* Type 1 – Dilutes, non-flocculent, free-settling (every particle settles independently.)
* Type 2 – Dilute, flocculent (particles can flocculate as they settle).
* Type 3 – Concentrated suspensions, zone settling, hindered settling (sludge thickening).
* Type 4 – Concentrated suspensions, compression (sludge thickening).
Different factors control the sedimentation rate in each. | 5 | Separation Processes |
An attempt to avoid the grid-collision problems was made by Robert Bussard in his Polywell design. This uses cusp magnetic field arrangements to produce "virtual electrodes" consisting of trapped electrons. The result is to produce an accelerating field similar to one produced by the grid wires in the fusor, but with no wires. Collisions with the electrons in the virtual electrodes are possible, but unlike the fusor, these cause no losses via spalled-off metal ions.
The polywell's biggest flaw is its ability to hold a plasma negative for any significant amount of time. In practice, any significant amount of negative charge vanishes quickly. Further, analysis by Todd Rider in 1995 suggests that any system that has non-equilibrium plasmas will suffer rapid losses of energy via bremsstrahlung. Bremsstrahlung occurs when a charged particle is rapidly accelerated, causing it to radiate x-rays, and thereby lose energy. In the case of IEC devices, including both the fusor and polywell, the collisions between recently accelerated ions entering the reaction area and low-energy ions and electrons forms a lower limit on bremsstrahlung that appears to be far higher than any possible rate of fusion. | 3 | Nuclear Fusion |
In late 2013, new results were published by a research team at Durham University which suggested progress. The scientists tried a new method for multiplying, cloning the original cells not in a 2D but in a 3D system.
A team took healthy dermal papillae from hair transplants and dissected them, then cultured them in a petri dish. In 30 hours they were able to produce 3000 dermal papilla cells. The goal was to create dermal papillae that when injected would reprogram cells around it to produce healthy hair. They chose to try the method by injecting the cloned cells in foreskin samples to "challenge" the cells, as the cells in the foreskin normally don't grow hair. The human skin samples were grafted on rats. After six weeks the cloned papillae cells formed brand-new hair follicles which were able to grow hair.
These are early results and as it is a new approach to hair cloning, several more studies and tests have to be conducted before they can move on to human testing. They also encountered new problems, such as that some of the newly grown hair appeared without pigmentation. | 2 | Tissue Engineering |
Below are low-FODMAP foods categorized by group according to the Monash University "Low-FODMAP Diet".
* Vegetables: alfalfa, bean sprouts, green beans, bok choy, capsicum (bell pepper), carrot, chives, fresh herbs, choy sum, cucumber, lettuce, tomato, zucchini, the green parts of leeks and spring onions
* Fruits: orange, grapes, honeydew melon (not watermelon)
* Protein: meats, fish, chicken, eggs, tofu (not silken), tempeh
* Dairy: lactose-free milk, lactose-free yoghurts, hard cheese
* Breads and cereals: rice, crisped rice, maize or corn, potatoes, quinoa, and breads made with their flours alone; however, oats and spelt are relatively low in FODMAPs
* Biscuits (cookies) and snacks: made with flour of cereals listed above, without high FODMAP ingredients added (such as onion, pear, honey, or polyol artificial sweeteners)
* Nuts and seeds: almonds (no more than ten nuts per serving), pumpkin seeds; not cashews or pistachios
* Beverage options: water, coffee, tea
Other sources confirm the suitability of these and suggest some additional foods. | 6 | Carbohydrates |
Industrial mixer settlers are commonly used in the copper, nickel, uranium, lanthanide, and cobalt hydrometallurgy industries, when solvent extraction processes are applied.
They are also used in the Nuclear reprocessing field to separate and purify primarily Uranium and Plutonium, removing the fission product impurities.
In the multiple countercurrent process, multiple mixer settlers are installed with mixing and settling chambers located at alternating ends for each stage (since the outlet of the settling sections feed the inlets of the adjacent stage's mixing sections). Mixer-settlers are used when a process requires longer residence times and when the solutions are easily separated by gravity. They require a large facility footprint, but do not require much headspace, and need limited remote maintenance capability for occasional replacement of mixing motors. (Colven, 1956; Davidson, 1957)
The equipment units can be arrayed as:
*extraction (moving an ion of interest from an aqueous phase to an organic phase),
*washing (rinsing entrained aqueous contaminant out of an organic phase containing the ion of interest), and
*stripping (moving an ion of interest from an organic phase into an aqueous phase). | 5 | Separation Processes |
UVC radiation is able to break chemical bonds. This leads to rapid aging of plastics and other material, and insulation and gaskets. Plastics sold as "UV-resistant" are tested only for the lower-energy UVB since UVC does not normally reach the surface of the Earth. When UV is used near plastic, rubber, or insulation, these materials may be protected by metal tape or aluminum foil. | 8 | Ultraviolet Radiation |
The Voitenko compressor is a shaped charge adapted from its original purpose of piercing thick steel armour to the task of accelerating shock waves. It was proposed by Anatoly Emelyanovich Voitenko (Анатолий Емельянович Войтенко), a Soviet scientist, in 1964. It slightly resembles a wind tunnel.
The Voitenko compressor initially separates a test gas from a shaped charge with a malleable steel plate. When the shaped charge detonates, most of its energy is focused on the steel plate, driving it forward and pushing the test gas ahead of it. Ames Research Center translated this idea into a self-destroying shock tube. A shaped charge accelerated the gas in a 3-cm glass-walled tube 2 meters in length. The velocity of the resulting shock wave was a phenomenal . The apparatus exposed to the detonation was, of course, completely destroyed, but not before useful data was extracted. In a typical Voitenko compressor, a shaped charge accelerates hydrogen gas, which in turn accelerates a thin disk up to about 40 km/s. A slight modification to the Voitenko compressor concept is a super-compressed detonation, a device that uses a compressible liquid or solid fuel in the steel compression chamber instead of a traditional gas mixture. A further extension of this technology is the explosive diamond anvil cell, utilizing multiple opposed shaped-charge jets projected at a single steel-encapsulated fuel, such as hydrogen. The fuels used in these devices, along with the secondary combustion reactions and long blast impulse, produce similar conditions to those encountered in fuel-air and thermobaric explosives.
This method of detonation produces energies over 100 keV (~10 K temperatures), suitable not only for nuclear fusion, but other higher-order quantum reactions as well. The UTIAS explosive-driven-implosion facility was used to produce stable, centered and focused hemispherical implosions to generate neutrons from D–D reactions. The simplest and most direct method proved to be in a predetonated stoichiometric mixture of deuterium and oxygen. The other successful method was using a miniature Voitenko-type compressor, where a plane diaphragm was driven by the implosion wave into a secondary small spherical cavity that contained pure deuterium gas at one atmosphere. In brief, PETN solid explosive is used to form a hemispherical shell (3–6 mm thick) in a 20-cm diameter hemispherical cavity milled in a massive steel chamber. The remaining volume is filled with a stoichiometric mixture of (H or D and O). This mixture is detonated by a very short, thin exploding wire located at the geometric center. The arrival of the detonation wave at the spherical surface instantly and simultaneously fires the explosive liner. The detonation wave in the explosive liner hits the metal cavity, reflects, and implodes on the preheated burnt gases, focuses at the center of the hemisphere (50 microseconds after the initiation of the exploding wire) and reflects, leaving behind a very small pocket (1 mm) of extremely high-temperature, high-pressure and high-density plasma. | 3 | Nuclear Fusion |
Due to the fact that no chemical change occurs after a charge-discharge cycle, the pigments theoretically retain their afterglow properties indefinitely. A reduction in light intensity only occurs very slowly, almost imperceptibly. This reduction increases with the degree of coloring of the pigments. Intensely colored types lose their intensity more quickly than neutral ones. High temperatures of up to several hundred degrees Celsius are not a problem. The only thing that needs to be avoided is prolonged contact with water or high humidity, as this creates a hydroxide layer that negatively affects the light emission intensity. | 0 | Luminescence |
Glow sticks are used by police, fire, and emergency medical services as light sources, similar to their military applications. Often, emergency rescue crews will hand out glow sticks in order to keep track of people at night, who may not have access to their own lighting. Glow sticks are sometimes attached to life vests and lifeboats on passenger and commercial vessels, to ensure night time visibility.
Glow sticks are often part of emergency kits to provide basic lighting and provide ease of identification in dark areas. They can be found in emergency lighting kits in buildings, public transportation vehicles, and subway stations. | 0 | Luminescence |
In 1980, V. Lubimov (Lyubimov) at the ITEP laboratory in Moscow claimed to have detected a mildly significant rest mass (30 ± 16) eV for the neutrino, by analyzing the energy spectrum of the β decay of tritium. The claim was disputed, and several other groups set out to check it by studying the decay of molecular tritium . It was known that some of the energy released by that decay would be diverted to the excitation of the decay products, including ; and this phenomenon could be a significant source of error in that experiment. This observation motivated numerous efforts to precisely compute the expected energy states of that ion in order to reduce the uncertainty of those measurements. Many have improved the computations since then, and now there is quite good agreement between computed and experimental properties; including for the isotopologues , , and . | 4 | Acids + Bases |
The first use of radioluminescence was in luminous paint containing radium, a natural radioisotope. Beginning in 1908, luminous paint containing a mixture of radium and copper-doped zinc sulfide was used to paint watch faces and instrument dials, giving a greenish glow. Phosphors containing copper-doped zinc sulfide (ZnS:Cu) yield blue-green light; copper and manganese-doped zinc sulfide (), yielding yellow-orange light are also used. Radium-based luminescent paint is no longer used due to the radiation hazard posed to persons manufacturing the dials. These phosphors are not suitable for use in layers thicker than 25 mg/cm, as the self-absorption of the light then becomes a problem. Zinc sulfide undergoes degradation of its crystal lattice structure, leading to gradual loss of brightness significantly faster than the depletion of radium.
ZnS:Ag coated spinthariscope screens were used by Ernest Rutherford in his experiments discovering the atomic nucleus.
Radium was used in luminous paint until the 1960s, when it was replaced with the other radioisotopes mentioned above due to health concerns. In addition to alpha and beta particles, radium emits penetrating gamma rays, which can pass through the metal and glass of a watch dial, and skin. A typical older radium wristwatch dial has a radioactivity of 3–10 kBq and could expose its wearer to an annual dose of 24 millisieverts if worn continuously. Another health hazard is its decay product, the radioactive gas radon, which constitutes a significant risk even at extremely low concentrations when inhaled. Radium's long half-life of 1600 years means that surfaces coated with radium paint, such as watch faces and hands, remain a health hazard long after their useful life is over. There are still millions of luminous radium clock, watch, and compass faces and aircraft instrument dials owned by the public. The case of the "Radium Girls", workers in watch factories in the early 1920s who painted watch faces with radium paint and later contracted fatal cancer through ingesting radium when they pointed their brushes with their lips, increased public awareness of the hazards of radioluminescent materials, and radioactivity in general. | 0 | Luminescence |
For small-scale hydrogen production, RO is sometimes used to prevent formation of mineral deposits on the surface of electrodes. | 5 | Separation Processes |
Carbohydrate Structure Database (CSDB) is a free curated database and service platform in glycoinformatics, launched in 2005 by a group of Russian scientists from [http://zioc.ru/?lang=en N.D. Zelinsky Institute of Organic Chemistry], Russian Academy of Sciences. CSDB stores published structural, taxonomical, bibliographic and NMR-spectroscopic data on natural carbohydrates and carbohydrate-related molecules. | 6 | Carbohydrates |
Gelatin is prepared from the denaturation of collagen and many desirable properties such as biodegradability, biocompatibility, non-immunogenity in physiological
environments, and easy processability make this polymer a good choice for tissue engineering applications. It is used in engineering tissues for the skin, bone and cartilage and is used commercially for skin replacements. | 2 | Tissue Engineering |
Cellulose sulphate is derived from cotton and, once processed appropriately, can be used as a biocompatible base in which to suspend cells. When the poly-anionic cellulose sulphate solution is immersed in a second, poly-cationic solution (e.g. pDADMAC), a semi-permeable membrane is formed around the suspended cells as a result of gelation between the two poly-ions. Both mammalian cell lines and bacterial cells remain viable and continue to replicate within the capsule membrane in order to fill-out the capsule. As such, in contrast to some other encapsulation materials, the capsules can be used to grow cells and act as such like a mini-bioreactor. The biocompatible nature of the material has been demonstrated by observation during studies using the cell-filled capsules themselves for implantation as well as isolated capsule material. Capsules formed from cellulose sulphate have been successfully used, showing safety and efficacy, in clinical and pre-clinical trials in both humans and animals, primarily as anti-cancer treatments, but also exploring possible uses for gene therapy or antibody therapies. Using cellulose sulphate it has been possible to manufacture encapsulated cells as a pharmaceutical product at large scale and fulfilling Good Manufacturing Process (cGMP) standards. This was achieved by the company [https://austrianova.com/ Austrianova] in 2007. | 2 | Tissue Engineering |
A sperm donor will usually be required to enter into a contract with a sperm bank to supply their semen, typically for a period of six to twenty-four months depending on the number of pregnancies which the sperm bank intends to produce from the donor. If a sperm bank has access to world markets e.g. by direct sales, or sales to clinics outside their own jurisdiction, a man may donate for a longer period than two years, as the risk of consanguinity is reduced (although local laws vary widely). Some sperm banks with access to world markets impose their own rules on the number of pregnancies which can be achieved in a given regional area or a state or country, and these sperm banks may permit donors to donate for four or five years, or even longer.
The contract may also specify the place and hours for donation, a requirement to notify the sperm bank in the case of acquiring a sexual infection, and the requirement not to have intercourse or to masturbate for a period of usually 2–3 days before making a donation.
The contract may also describe the types of treatment for which the donated sperm may be used, such as artificial insemination and IVF, and whether the donors sperm may be used in surrogacy arrangements. It may also stipulate whether the sperm may be used for research or training purposes. In certain cases, a sperm donor may specify the maximum number of offspring or families which may be produced from the donors sperm. Family may be defined as a couple who may each bear children from the same donor. The contract may also require consent if the donor's samples are to be exported. In the United Kingdom, for example, the maximum number of families for which a donor is permitted to bear children is ten, but a sperm bank or fertility center in the UK may export sperm to other fertility centers so that this may be used to produce more pregnancies abroad. Where this happens, consent must be provided by the donor. Faced with a growing demand for donor sperm, sperm banks may try to maximize the use of a donor whilst still reducing the risk of consanguinity. In legislations with a national register of sperm donors or a national regulatory body, a sperm donor may be required to fill in a separate form of consent which will be registered with the regulatory authority. In the United Kingdom this body is the HFEA.
A sperm donor generally produces and collects sperm at a sperm bank or clinic by masturbation in a private room or cabin, known as a mens production room (UK), donor cabin' (DK) or a masturbatorium (US). Many of these facilities contain pornography such as videos/DVD, magazines, and/or photographs which may assist the donor in becoming aroused in order to facilitate production of the ejaculate, also known as the "semen sample" but the increasing usage of porn in the U.S. has dulled many men to its effects. Often, using any type of personal lubricant, saliva, oil or anything else to lubricate and stimulate the genitals is prohibited as it can contaminate the semen sample and have negative impacts on the quality and health of sperm. In some circumstances, it may also be possible for semen from donors to be collected during sexual intercourse with the use of a collection condom which results in higher sperm counts. | 1 | Cryobiology |
Gastruloids are three dimensional aggregates of embryonic stem cells (ESCs) that, when cultured in specific conditions, exhibit an organization resembling that of an embryo. They develop with three orthogonal axes and contain the primordial cells for various tissues derived from the three germ layers, without the presence of extraembryonic tissues. Notably, they do not possess forebrain, midbrain, and hindbrain structures. Gastruloids serve as a valuable model system for studying mammalian development, including human development, as well as diseases associated with it. They are a model system an embryonic organoid for the study of mammalian development (including humans) and disease. | 2 | Tissue Engineering |
Bullous keratopathy that is characterized by corneal stromal edema related to cell loss and endothelial decompensation as well as subepithelial fibrosis and corneal vascularization in further cases, results vision problems due to loss of corneal transparency. Fibrin glue is used as a sutureless method onto the corneal surface to fix amniotic membrane that is cryopreserved. Complete re-epithelialization on the ocular surface with no symptom is achieved in 3 weeks. Results show that fibrin glue fixation is easy, reliable and efficient with the corneal surface. | 2 | Tissue Engineering |
In order to achieve its objectives EFDA conducts the following group of activities:
* Collective use of JET, the world's largest fusion experiment
* Reinforced coordination of fusion physics and technology research and development in EU laboratories.
* Training and carrier development of researchers, promoting links to universities and carrying out support actions for the benefit of the fusion programme.
* EU contributions to international collaborations outside F4E
EFDA coordinates a range of activities to be carried out by the Associations in 7 key physics and technology areas. The implementation of these activities benefits from structures so called Task Forces and Topical Groups. The European Task Forces on [https://web.archive.org/web/20091222223222/http://www.efda.org/about_efda/activities-plasma_wall_interaction.htm Plasma Wall Interaction] (PWI) and on [https://web.archive.org/web/20091222223205/http://www.efda.org/about_efda/activities-integrated_tokamak_modelling.htm Integrated Tokamak Modelling] (ITM) set up respectively in 2002 and 2003. To strengthen the co-ordination in other key areas five Topical Groups have been set up in 2008: on [https://web.archive.org/web/20090419230108/http://www.efda.org/about_efda/activities-fusion_materials.htm Fusion Materials Development], [https://web.archive.org/web/20091222223153/http://www.efda.org/about_efda/activities-diagnostics.htm Diagnostics], [https://web.archive.org/web/20091222223159/http://www.efda.org/about_efda/activities-heating_and_current_drive.htm Heating and Current Drive], [https://web.archive.org/web/20091222223242/http://www.efda.org/about_efda/activities-transport.htm Transport] and [https://web.archive.org/web/20091222223217/http://www.efda.org/about_efda/activities-magnetohydrodinamics.htm Plasma Stability and Control]. | 3 | Nuclear Fusion |
After a spate of attacks in London in 2017, the Home Office said it would consider changes in laws and measures regarding sales of acid, as well as changes in prosecution and sentencing guidelines. As of 2017, it is unlawful to carry acid with the intent to cause harm. Attacks are prosecuted as acts of actual bodily harm and grievous bodily harm. Three quarters of police investigations do not end in prosecution, either because the attacker could not be found, or because the victim is unwilling to press charges. According to ASTI, of the 2,078 acid attack crimes recorded for the years 2011–2016 in UK, only 414 of those crimes resulted in charges being brought. Most acid attack crimes happened in London, where over 1,200 cases were recorded over the past five years. From 2011 to 2016 there were 1,464 crimes involving acid or corrosive substance. Northumbria recorded the second highest with 109 recorded attacks, Cambridgeshire had 69 attacks, Hertfordshire 67, Greater Manchester 57 and Humberside 52.
The Offensive Weapons Act 2019 made provisions for crimes related to acid attacks, including bringing in greater regulation of the sale of corrosive products and making it an offence to carry a corrosive substance in a public place without good reason. | 4 | Acids + Bases |
Asperomagnetism is the equivalent of ferromagnetism for a disordered system with random magnetic moments. It is defined by short range correlations of locked magnetic moments within small noncrystalline regions, with average long range correlations. Speromagnets possess a permanent net magnetic moment.
An example of a asperomagnets is amorphous YFe and DyNi. | 7 | Magnetic Ordering |
The US funded a magnetic mirror program in the late 1970s and early 1980s. This program resulted in a series of magnetic mirror devices including: 2X, Baseball I, Baseball II, the Tandem Mirror Experiment and upgrade, the Mirror Fusion Test Facility, and MFTF-B. These machines were built and tested at LLNL from the late 1960s to the mid-1980s. The final machine, MFTF cost 372 million dollars and was, at that time, the most expensive project in LLNL history. It opened on February 21, 1986, and immediately closed, allegedly to balance the federal budget. | 3 | Nuclear Fusion |
A superparamagnetic system can be measured with AC susceptibility measurements, where an applied magnetic field varies in time, and the magnetic response of the system is measured. A superparamagnetic system will show a characteristic frequency dependence: When the frequency is much higher than 1/τ, there will be a different magnetic response than when the frequency is much lower than 1/τ, since in the latter case, but not the former, the ferromagnetic clusters will have time to respond to the field by flipping their magnetization. The precise dependence can be calculated from the Néel–Arrhenius equation, assuming that the neighboring clusters behave independently of one another (if clusters interact, their behavior becomes more complicated). It is also possible to perform magneto-optical AC susceptibility measurements with magneto-optically active superparamagnetic materials such as iron oxide nanoparticles in the visible wavelength range. | 7 | Magnetic Ordering |
The hexosamine biosynthetic pathways product, UDP-GlcNAc, is utilized by OGT to catalyze the addition of O-GlcNAc. This pathway integrates information about the concentrations of various metabolites including amino acids, carbohydrates, fatty acids, and nucleotides. Consequently, UDP-GlcNAc levels are sensitive to cellular metabolite levels. OGT activity is in part regulated by UDP-GlcNAc concentration, making a link between cellular nutrient status and O'-GlcNAc.
Glucose deprivation causes a decline in UDP-GlcNAc levels and an initial decline in O-GlcNAc, but counterintuitively, O-GlcNAc is later significantly upregulated. This later increase has been shown to be dependent on AMPK and p38 MAPK activation, and this effect is partially due to increases in OGT mRNA and protein levels. It has also been suggested that this effect is dependent on calcium and CaMKII. Activated p38 is able to recruit OGT to specific protein targets, including neurofilament H; O-GlcNAc modification of neurofilament H enhances its solubility. During glucose deprivation, glycogen synthase is modified by O-GlcNAc which inhibits its activity. | 6 | Carbohydrates |
Some notable hysteretic models are listed below with their associated fields.
* Bean's critical state model (magnetism)
* Bouc–Wen model (structural engineering)
* Ising model (magnetism)
* Jiles–Atherton model (magnetism)
* Novak–Tyson model (cell-cycle control)
* Preisach model (magnetism)
* Stoner–Wohlfarth model (magnetism) | 7 | Magnetic Ordering |
In fusion systems that are in thermal equilibrium, the particles are in a Maxwell–Boltzmann distribution, meaning the particles have a range of energies centered around the plasma temperature. The sun, magnetically confined plasmas and inertial confinement fusion systems are well modeled to be in thermal equilibrium. In these cases, the value of interest is the fusion cross-section averaged across the Maxwell–Boltzmann distribution. The Naval Research Lab's plasma physics formulary tabulates Maxwell averaged fusion cross sections reactivities in .
For energies the data can be represented by:
with in units of keV. | 3 | Nuclear Fusion |
Plants produce glucosinolates in response to the degree of herbivory being suffered. Their production in relation to atmospheric CO concentrations is complex: increased CO can give increased, decreased or unchanged production and there may be genetic variation within the Brassicales. | 6 | Carbohydrates |
The first successful results with pyroelectric fusion using a tritiated target was reported in 2010. Putterman and Naranjo worked with T. Venhaus of Los Alamos National Laboratory to measure a 14.1 MeV neutron signal far above background. | 3 | Nuclear Fusion |
Mannans are polymers containing the sugar mannose as a principal component.
They are a type of polysaccharide found in hemicellulose, a major source of biomass found in higher plants such as softwoods. These polymers also typically contain two other sugars, galactose and glucose. They are often branched (unlike cellulose). | 6 | Carbohydrates |
A blastoid is an embryoid, a stem cell-based embryo model which, morphologically and transcriptionally resembles the early, pre-implantation, mammalian conceptus, called the blastocyst. The first blastoids were created by the Nicolas Rivron laboratory by combining mouse embryonic stem cells and mouse trophoblast stem cells. Upon in vitro development, blastoids generate analogs of the primitive endoderm cells, thus comprising analogs of the three founding cell types of the conceptus (epiblast, trophoblast and primitive endoderm), and recapitulate aspects of implantation on being introduced into the uterus of a compatible female. Mouse blastoids have not shown the capacity to support the development of a foetus and are thus generally not considered as an embryo but rather as a model. As compared to other stem cell-based embryo models (e.g., Gastruloids), blastoids model the preimplantation stage and the integrated development of the conceptus including the embryo proper and the two extraembryonic tissues (trophectoderm and primitive endoderm). The blastoid is a model system for the study of mammalian development and disease. It might be useful for the identification of therapeutic targets and preclinical modelling. | 2 | Tissue Engineering |
The diameter of the microcapsules is an important factor that influences both the immune response towards the cell microcapsules as well as the mass transport across the capsule membrane. Studies show that the cellular response to smaller capsules is much lesser as compared to larger capsules and in general the diameter of the cell loaded microcapsules should be between 350-450 µm so as to enable effective diffusion across the semi-permeable membrane. | 2 | Tissue Engineering |
Osazone are a class of carbohydrate derivatives found in organic chemistry formed when reducing sugars are reacted with excess of phenylhydrazine at boiling temperatures. | 6 | Carbohydrates |
Fluorescent dyes find a wide use in industry, going under the name of "neon colors", such as:
* Multi-ton scale usages in textile dyeing and optical brighteners in laundry detergents
* Advanced cosmetic formulations
* Safety equipment and clothing
* Organic light-emitting diodes (OLEDs)
* Fine arts and design (posters and paintings)
* Synergists for insecticides and experimental drugs
* Dyes in highlighters to give off a glow-like effect
* Solar panels to collect more light / wavelengths
* Fluorescent sea dye is used to help airborne search and rescue teams locate objects in the water | 0 | Luminescence |
The majority of current advancements in muscle tissue engineering reside in the skeletal muscle category, so the majority of these examples will have to do with skeletal muscle engineering and regeneration. We will review a couple of examples of smooth muscle tissue engineering and cardiac muscle tissue engineering in this section as well. | 2 | Tissue Engineering |
Sperimagnetism is the equivalent of ferrimagnetism for a disordered system with two or more species of magnetic moments, with at least one species locked in random magnetic moments. Sperimagnets possess a permanent net magnetic moment. When all species are the same, this phase is equivalent to asperomagnetism. | 7 | Magnetic Ordering |
* Cryogenics, the study of the production and behaviour of materials at very low temperatures and the study of producing extremely low temperatures
* Cryoelectronics, the study of superconductivity under cryogenic conditions and its applications
* Cryosphere, those portions of Earth's surface where water ice naturally occurs
* Cryotron, a switch that uses superconductivity
* Cryovolcano, a theoretical type of volcano that erupts volatiles instead of molten rock | 1 | Cryobiology |
The approximate knife advance rate can be determined for a set of operating conditions using table 6 below. The table indicates the number of hours that the filter can operate in a one-inch pre coat cake; the required condition is that the advance blade must be at a constant position. This method can be used to check for optimum operation range.
If the operating parameter is higher than the optimum range, the user can reduce the knife advance rate and use a tighter grade of filter aid. This will result in less filter aid used (lower capital cost) and less filter aid being removed (lower disposal cost). However, if the operating parameter is lower than the optimum range, the user can increase the knife advanced rate (more production) and decrease the drum speed for less filter air usage (reduced operating cost). | 5 | Separation Processes |
In the recent past the problem of removing the deleterious iron particles from a process stream had a few alternatives. Magnetic separation was typically limited and moderately effective. Magnetic separators that used permanent magnets could generate fields of low intensity only. These worked well in removing ferrous tramp but not fine paramagnetic particles. Thus high-intensity magnetic separators that were effective in collecting paramagnetic particles came into existence. These focus on the separation of very fine particles that are paramagnetic.
The current is passed through the coil, which creates a magnetic field, which magnetizes the expanded steel matrix ring. The paramagnetic matrix material behaves like a magnet in the magnetic field and thereby attracts the fines. The ring is rinsed when it is in the magnetic field and all the non-magnetic particles are carried with the rinse water. Next as the ring leaves the magnetic zone the ring is flushed and a vacuum of about – 0.3 bars is applied to remove the magnetic particles attached to the matrix ring. | 5 | Separation Processes |
Tanning lamps, also known as tanning bulbs or tanning tubes, produce the ultraviolet light in tanning devices. The performance (or output) varies widely between brands and styles. Most are low-pressure fluorescent tubes, but high-pressure bulbs also exist. The electronics systems and number of lamps affect performance, but to a lesser degree than the lamp itself. Tanning lamps are regulated separately from tanning beds in most countries, as they are the consumable portion of the system. | 8 | Ultraviolet Radiation |
Independently of the range of the interaction, at low enough temperature the magnetization is positive.
Conjecturally, in each of the low temperature extremal states the truncated correlations decay algebraically. | 7 | Magnetic Ordering |
The ions undergoing fusion in many systems will essentially never occur alone but will be mixed with electrons that in aggregate neutralize the ions' bulk electrical charge and form a plasma. The electrons will generally have a temperature comparable to or greater than that of the ions, so they will collide with the ions and emit x-ray radiation of 10–30 keV energy, a process known as Bremsstrahlung.
The huge size of the Sun and stars means that the x-rays produced in this process will not escape and will deposit their energy back into the plasma. They are said to be opaque to x-rays. But any terrestrial fusion reactor will be optically thin for x-rays of this energy range. X-rays are difficult to reflect but they are effectively absorbed (and converted into heat) in less than mm thickness of stainless steel (which is part of a reactor's shield). This means the bremsstrahlung process is carrying energy out of the plasma, cooling it.
The ratio of fusion power produced to x-ray radiation lost to walls is an important figure of merit. This ratio is generally maximized at a much higher temperature than that which maximizes the power density (see the previous subsection). The following table shows estimates of the optimum temperature and the power ratio at that temperature for several reactions:
The actual ratios of fusion to Bremsstrahlung power will likely be significantly lower for several reasons. For one, the calculation assumes that the energy of the fusion products is transmitted completely to the fuel ions, which then lose energy to the electrons by collisions, which in turn lose energy by Bremsstrahlung. However, because the fusion products move much faster than the fuel ions, they will give up a significant fraction of their energy directly to the electrons. Secondly, the ions in the plasma are assumed to be purely fuel ions. In practice, there will be a significant proportion of impurity ions, which will then lower the ratio. In particular, the fusion products themselves must remain in the plasma until they have given up their energy, and will remain for some time after that in any proposed confinement scheme. Finally, all channels of energy loss other than Bremsstrahlung have been neglected. The last two factors are related. On theoretical and experimental grounds, particle and energy confinement seem to be closely related. In a confinement scheme that does a good job of retaining energy, fusion products will build up. If the fusion products are efficiently ejected, then energy confinement will be poor, too.
The temperatures maximizing the fusion power compared to the Bremsstrahlung are in every case higher than the temperature that maximizes the power density and minimizes the required value of the fusion triple product. This will not change the optimum operating point for – very much because the Bremsstrahlung fraction is low, but it will push the other fuels into regimes where the power density relative to – is even lower and the required confinement even more difficult to achieve. For – and –, Bremsstrahlung losses will be a serious, possibly prohibitive problem. For –, p– and p– the Bremsstrahlung losses appear to make a fusion reactor using these fuels with a quasineutral, isotropic plasma impossible. Some ways out of this dilemma have been considered but rejected. This limitation does not apply to non-neutral and anisotropic plasmas; however, these have their own challenges to contend with. | 3 | Nuclear Fusion |
Basically there are five types of discharge that are used for the rotary vacuum drum filter such as belt, scraper, roll, string and pre coat discharge. | 5 | Separation Processes |
2-Furonitrile, a pharmaceutical intermediate and potential artificial sweetening agent has been prepared in good yield by treating furfural with a mixture of hydrazoic acid () and perchloric acid () in the presence of magnesium perchlorate in the benzene solution at 35 °C.
The all gas-phase iodine laser (AGIL) mixes gaseous hydrazoic acid with chlorine to produce excited nitrogen chloride, which is then used to cause iodine to lase; this avoids the liquid chemistry requirements of COIL lasers. | 4 | Acids + Bases |
Many microorganisms living in sea ice possess AFPs that belong to a single family. The diatoms Fragilariopsis cylindrus and F. curta play a key role in polar sea ice communities, dominating the assemblages of both platelet layer and within pack ice. AFPs are widespread in these species, and the presence of AFP genes as a multigene family indicates the importance of this group for the genus Fragilariopsis. AFPs identified in F. cylindrus belong to an AFP family which is represented in different taxa and can be found in other organisms related to sea ice (Colwellia spp., Navicula glaciei, Chaetoceros neogracile and Stephos longipes and Leucosporidium antarcticum) and Antarctic inland ice bacteria (Flavobacteriaceae), as well as in cold-tolerant fungi (Typhula ishikariensis, Lentinula edodes and Flammulina populicola).
Several structures for sea ice AFPs have been solved. This family of proteins fold into a beta helix that form a flat ice-binding surface. Unlike the other AFPs, there is not a singular sequence motif for the ice-binding site.
AFP found from the metagenome of the ciliate Euplotes focardii and psychrophilic bacteria has an efficient ice re-crystallization inhibition ability. 1 μM of Euplotes focardii consortium ice-binding protein (EfcIBP) is enough for the total inhibition of ice re-crystallization in –7.4 °C temperature. This ice-recrystallization inhibition ability helps bacteria to tolerate ice rather than preventing the formation of ice. EfcIBP produces also thermal hysteresis gap, but this ability is not as efficient as the ice-recrystallization inhibition ability. EfcIBP helps to protect both purified proteins and whole bacterial cells in freezing temperatures. Green fluorescent protein is functional after several cycles of freezing and melting when incubated with EfcIBP. Escherichia coli survives longer periods in 0 °C temperature when the efcIBP gene was inserted to E. coli genome. EfcIBP has a typical AFP structure consisting of multiple beta-sheets and an alpha-helix. Also, all the ice-binding polar residues are at the same site of the protein. | 1 | Cryobiology |
Zenobi-Wong works in the area of tissue engineering, in particular for cartilage regeneration. She develops functional biomaterials which mimic the extracellular matrix. The biofabrication techniques used to develop these materials include electrospinning, casting, two-photon polymerization and bioprinting.
Zenobi-Wong holds four licensed patents in the fields of tissue engineering, tissue engineering techniques, and gene expression assays. She was one of the originators of the MSc Biomedical Engineering program at ETH Zürich, and developed several graduate level courses in tissue engineering and biomedical engineering. Zenobi-Wong currently serves as President of the Swiss Society for Biomaterials and Regenerative Medicine, and as secretary general of the International Society of Biofabrication. | 2 | Tissue Engineering |
When acids contact the skin, response time can affect the severity of burns. If washed away with water or neutralized promptly, burns can be minimized or avoided entirely. However, areas unprotected by skin, such as the cornea of the eye or the lips, may be burned immediately on contact.
Many victims are attacked in an area without immediate access to water, or unable to see due to being blinded or forced to keep their eyes closed to prevent additional burns to the eye. Treatment for burn victims remains inadequate in many developing nations where incidence is high. Medical underfunding has resulted in very few burn centers available for victims in countries such as Uganda, Bangladesh, and Cambodia., Uganda has one specialized burn center in the entire nation, opening in 2003; Cambodia has only one burn facility for victims, and scholars estimate that only 30% of the Bangladeshi community has access to health care.
In addition to inadequate medical capabilities, many acid assault victims fail to report to the police due to a lack of trust in the force, a sense of hopelessness due to the attackers' impunity, and fear of retribution by the assailant.
These problems are exacerbated by a lack of knowledge of how to treat burns: some victims have applied oil to the acid, rather than rinsing thoroughly and completely with water for 30 minutes or longer to neutralize the acid. Such home remedies only serve to increase the severity of damage, as they do not counteract the acidity. | 4 | Acids + Bases |
A tree wrap or tree wrapping is a wrap of garden tree saplings, roses, and other delicate plants to protect them from frost damage (e.g. frost cracks or complete death). In the past it was made of straw (straw wrap) . Now there are commercial tree wrap materials, such as crepe paper or burlap tapes. Tree wrapping is also used to prevent saplings from sunscald and drying of the bark. A disadvantage of tape wrapping is dampness under the wrapping during rainy seasons. | 1 | Cryobiology |
Giving the critical exponents explicitly in the equation of state, Arrott and Noakes proposed:
Where are free parameters. In these modified Arrott plots, data is plotted as versus . In the case of classical Landau theory, and and this equation reduces to the linear versus plot. However, the equation also allows for other values of and , since real ferromagnets often do not have critical exponents exactly consistent with a simple mean field theory ferromagnetism.
The use of the correct critical exponents for a given system can help give straight lines on the Arott plot, but not in cases such as low magnetic field and amorphous materials. While mean field theory is a more reasonable model for ferromagnets at higher magnetic fields, the presence of more than one magnetic domain in real magnets means that especially at low magnetic fields, the experimentally measured macroscopic magnetic field (which is an average over the whole sample) will not be a reasonable way to determine the local magnetic field (which is felt by a single atom). Therefore, magnetization data taken at low magnetic fields should be ignored for the purposes of Arrott plots. | 7 | Magnetic Ordering |
Gelatin is the denatured form of collagen. Gelatin possesses several advantages for tissue-engineering application: they attract fibroblasts, are non-immunogenic, easy to manipulate and boost the formation of epithelium. There are three types of gelatin-based scaffolds:
* Gelatin-oxidized dextran matrix
* Gelatin-chitosan-oxidized dextran matrix
* Gelatin-glucan matrix
* Gelatin-hyaluronate matrix
* Gelatin-chitosan hyaluronic acid matrix.
Glucan is a polysaccharide with antibacterial, antiviral and anticoagulant properties. Hyaluronic acid is added to improve the biological and mechanical properties of the matrix. | 2 | Tissue Engineering |
Unhindered settling is a process that removes the discrete particles in a very low concentration without interference from nearby particles. In general, if the concentration of the solutions is lower than 500 mg/L total suspended solids, sedimentation will be considered discrete. Concentrations of raceway effluent total suspended solids (TSS) in the west are usually less than 5 mg/L net. TSS concentrations of off-line settling basin effluent are less than 100 mg/L net. The particles keep their size and shape during discrete settling, with an independent velocity. With such low concentrations of suspended particles, the probability of particle collisions is very low and consequently the rate of flocculation is small enough to be neglected for most calculations. Thus the surface area of the settling basin becomes the main factor of sedimentation rate. All continuous flow settling basins are divided into four parts: inlet zone, settling zone, sludge zone and outlet zone (Figure 2).
In the inlet zone, flow is established in a same forward direction. Sedimentation occurs in the settling zone as the water flow towards to outlet zone. The clarified liquid is then flow out from outlet zone.
Sludge zone: settled will be collected here and usually we assume that it is removed from water flow once the particles arrives the sludge zone.
In an ideal rectangular sedimentation tank, in the settling zone, the critical particle enters at the top of the settling zone, and the settle velocity would be the smallest value to reach the sludge zone, and at the end of outlet zone, the velocity component of this critical particle are the settling velocity in vertical direction (v) and in horizontal direction (v).
From Figure 1, the time needed for the particle to settle;
:t =H/v=L/v (3)
Since the surface area of the tank is WL, and v = Q/WL, v = Q/WH, where Q is the flow rate and W, L, H is the width, length, depth of the tank.
According to Eq. 1, this also is a basic factor that can control the sedimentation tank performance which called overflow rate.
Eq. 2 also shows that the depth of sedimentation tank is independent to the sedimentation efficiency, only if the forward velocity is low enough to make sure the settled mass would not suspended again from the tank floor. | 5 | Separation Processes |
Several groups have extensively studied several natural and synthetic polymers with the goal of developing the most suitable biomaterial for cell microencapsulation. Extensive work has been done using alginates which are regarded as the most suitable biomaterials for cell microencapsulation due to their abundance, excellent biocompatibility and biodegradability properties. Alginate is a natural polymer which can be extracted from seaweed and bacteria with numerous compositions based on the isolation source.
Alginate is not free from all criticism. Some researchers believe that alginates with high-M content could produce an inflammatory response and an abnormal cell growth while some have demonstrated that alginate with high-G content lead to an even higher cell overgrowth and inflammatory reaction in vivo as compared to intermediate-G alginates.
Even ultrapure alginates may contain endotoxins, and polyphenols which could compromise the biocompatibility of the resultant cell microcapsules. It has been shown that even though purification processes successfully lower endotoxin and polyphenol content in the processed alginate, it is difficult to lower the protein content and the purification processes could in turn modify the properties of the biomaterial. Thus it is essential that an effective purification process is designed so as to remove all the contaminants from alginate before it can be successfully used in clinical applications. | 2 | Tissue Engineering |
Galactogen is synthesized by secretory cells in the albumen gland of adult female snails and later transferred to the egg. This process is under neurohormonal control, notably by the brain galactogenin. The biochemical pathways for glycogen and galactogen synthesis are closely related. Both use glucose as a common precursor and its conversion to activated galactose is catalyzed by UDP-glucose 4-epimerase and galactose-1-P uridyl-transferase. This enables glucose to be the common precursor for both glycogenesis and galactogenesis. In fact, both polysaccharides are found in the same secretory cells of the albumen gland and are subject to independent seasonal variations. Glycogen accumulates in autumn as a general energy storage for hibernation, whereas galactogen is synthesized during spring in preparation of egg-laying. It is commonly accepted that galactogen production is restricted to embryo nutrition and therefore is mainly transferred to eggs.
Little is known about the galactogen-synthesizing enzymes. A D-galactosyltransferase was described in the albumen gland of Helix pomatia. This enzyme catalyzes the transfer of D-galactose to a (1→6) linkage and is dependent upon the presence of acceptor galactogen. Similarly, a β-(1→3)-galactosyltransferase activity has been detected in albumen gland extracts from Limnaea stagnalis.
In embryos and fasting newly hatched snails, galactogen is most likely an important donor (via galactose) of metabolic intermediates. In feeding snails, the primary diet is glucose-containing starch and cellulose. These polymers are digested and contribute glucose to the pathways of intermediary metabolism. Galactogen consumption begins at the gastrula stage and continues throughout development. Up to 46-78 % of egg galactogen disappears during embryo development. The remainder is used up within the first days after hatching.
Only snail embryos and hatchlings are able to degrade galactogen, whereas other animals and even adult snails do not. β-galactosidase may be important in the release of galactose from galactogen; however, most of the catabolic pathway of this polysaccharide is still unknown. | 6 | Carbohydrates |
Indiglo backlights typically emit a distinct greenish-blue color and evenly light the entire display or dial. Certain Indiglo models, e.g., Timex Datalink USB, use a negative liquid-crystal display so that only the digits are illuminated, rather than the entire display. | 0 | Luminescence |
At least for vitiligo, narrowband ultraviolet B (UVB) nanometer phototherapy is now used more commonly than PUVA since it does not require the use of the psoralen. As with PUVA, treatment is carried out 2 to 3 times a week in a clinic or every day at home, and there is no need to use psoralen.
Narrowband UVB therapy is less effective for the legs and hands, compared to the face and neck. To the hands and legs PUVA may be more effective. The reason can be because UVA penetrates deeper in the skin, and the melanocytes in the skin of the hands and legs are positioned deeper in the skin. Narrowband UVB 311 nanometer is blocked by the topmost skin layer, and UVA 365 nanometer reaches the melanocytes that are in the bottom skin layer.
Melanin is a dark pigment of the skin and the melanocytes produce it. The melanocytes produce melanin when their receptors detect UV light. The purpose of the melanin is to block UV light so that it will not cause damage to the body cells under the skin. | 8 | Ultraviolet Radiation |
An important fusion process is the stellar nucleosynthesis that powers stars, including the Sun. In the 20th century, it was recognized that the energy released from nuclear fusion reactions accounts for the longevity of stellar heat and light. The fusion of nuclei in a star, starting from its initial hydrogen and helium abundance, provides that energy and synthesizes new nuclei. Different reaction chains are involved, depending on the mass of the star (and therefore the pressure and temperature in its core).
Around 1920, Arthur Eddington anticipated the discovery and mechanism of nuclear fusion processes in stars, in his paper The Internal Constitution of the Stars. At that time, the source of stellar energy was unknown; Eddington correctly speculated that the source was fusion of hydrogen into helium, liberating enormous energy according to Einsteins equation . This was a particularly remarkable development since at that time fusion and thermonuclear energy had not yet been discovered, nor even that stars are largely composed of hydrogen (see metallicity). Eddingtons paper reasoned that:
# The leading theory of stellar energy, the contraction hypothesis, should cause the rotation of a star to visibly speed up due to conservation of angular momentum. But observations of Cepheid variable stars showed this was not happening.
# The only other known plausible source of energy was conversion of matter to energy; Einstein had shown some years earlier that a small amount of matter was equivalent to a large amount of energy.
# Francis Aston had also recently shown that the mass of a helium atom was about 0.8% less than the mass of the four hydrogen atoms which would, combined, form a helium atom (according to the then-prevailing theory of atomic structure which held atomic weight to be the distinguishing property between elements; work by Henry Moseley and Antonius van den Broek would later show that nucleic charge was the distinguishing property and that a helium nucleus, therefore, consisted of two hydrogen nuclei plus additional mass). This suggested that if such a combination could happen, it would release considerable energy as a byproduct.
# If a star contained just 5% of fusible hydrogen, it would suffice to explain how stars got their energy. (It is now known that most ordinary stars contain far more than 5% hydrogen.)
# Further elements might also be fused, and other scientists had speculated that stars were the "crucible" in which light elements combined to create heavy elements, but without more accurate measurements of their atomic masses nothing more could be said at the time.
All of these speculations were proven correct in the following decades.
The primary source of solar energy, and that of similar size stars, is the fusion of hydrogen to form helium (the proton–proton chain reaction), which occurs at a solar-core temperature of 14 million kelvin. The net result is the fusion of four protons into one alpha particle, with the release of two positrons and two neutrinos (which changes two of the protons into neutrons), and energy. In heavier stars, the CNO cycle and other processes are more important. As a star uses up a substantial fraction of its hydrogen, it begins to synthesize heavier elements. The heaviest elements are synthesized by fusion that occurs when a more massive star undergoes a violent supernova at the end of its life, a process known as supernova nucleosynthesis. | 3 | Nuclear Fusion |
The surface of a collapsing bubble like those seen in both SBSL and MBSL serves as a boundary layer between the liquid and vapor phases of the solution. | 0 | Luminescence |
In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules, usually related to the spins of electrons, align in a regular pattern with neighboring spins (on different sublattices) pointing in opposite directions. This is, like ferromagnetism and ferrimagnetism, a manifestation of ordered magnetism. The phenomenon of antiferromagnetism was first introduced by Lev Landau in 1933.
Generally, antiferromagnetic order may exist at sufficiently low temperatures, but vanishes at and above the Néel temperature – named after Louis Néel, who had first in the West identified this type of magnetic ordering. Above the Néel temperature, the material is typically paramagnetic. | 7 | Magnetic Ordering |
Theoretically, IVF could be performed by collecting the contents from the fallopian tubes or uterus after natural ovulation, mixing it with sperm, and reinserting the fertilised ova into the uterus. However, without additional techniques, the chances of pregnancy would be extremely small. The additional techniques that are routinely used in IVF include ovarian hyperstimulation to generate multiple eggs, ultrasound-guided transvaginal oocyte retrieval directly from the ovaries, co-incubation of eggs and sperm, as well as culture and selection of resultant embryos before embryo transfer into a uterus. | 1 | Cryobiology |
Decellularization (also spelled decellularisation in British English) is the process used in biomedical engineering to isolate the extracellular matrix (ECM) of a tissue from its inhabiting cells, leaving an ECM scaffold of the original tissue, which can be used in artificial organ and tissue regeneration. Organ and tissue transplantation treat a variety of medical problems, ranging from end organ failure to cosmetic surgery. One of the greatest limitations to organ transplantation derives from organ rejection caused by antibodies of the transplant recipient reacting to donor antigens on cell surfaces within the donor organ. Because of unfavorable immune responses, transplant patients suffer a lifetime taking immunosuppressing medication. Stephen F. Badylak pioneered the process of decellularization at the McGowan Institute for Regenerative Medicine at the University of Pittsburgh. This process creates a natural biomaterial to act as a scaffold for cell growth, differentiation and tissue development. By recellularizing an ECM scaffold with a patient’s own cells, the adverse immune response is eliminated. Nowadays, commercially available ECM scaffolds are available for a wide variety of tissue engineering. Using peracetic acid to decellularize ECM scaffolds have been found to be false and only disinfects the tissue.
With a wide variety of decellularization-inducing treatments available, combinations of physical, chemical, and enzymatic treatments are carefully monitored to ensure that the ECM scaffold maintains the structural and chemical integrity of the original tissue. Scientists can use the acquired ECM scaffold to reproduce a functional organ by introducing progenitor cells, or adult stem cells (ASCs), and allowing them to differentiate within the scaffold to develop into the desired tissue. The produced organ or tissue can be transplanted into a patient. In contrast to cell surface antibodies, the biochemical components of the ECM are conserved between hosts, so the risk of a hostile immune response is minimized. Proper conservation of ECM fibers, growth factors, and other proteins is imperative to the progenitor cells differentiating into the proper adult cells. The success of decellularization varies based on the components and density of the applied tissue and its origin. The applications to the decellularizing method of producing a biomaterial scaffold for tissue regeneration are present in cardiac, dermal, pulmonary, renal, and other types of tissues. Complete organ reconstruction is still in the early levels of development. | 2 | Tissue Engineering |
Many women of sub-Saharan Africa choose to foster their children to infertile women. IVF enables these infertile women to have their own children, which imposes new ideals to a culture in which fostering children is seen as both natural and culturally important. Many infertile women are able to earn more respect in their society by taking care of the children of other mothers, and this may be lost if they choose to use IVF instead. As IVF is seen as unnatural, it may even hinder their societal position as opposed to making them equal with fertile women. It is also economically advantageous for infertile women to raise foster children as it gives these children greater ability to access resources that are important for their development and also aids the development of their society at large. If IVF becomes more popular without the birth rate decreasing, there could be more large family homes with fewer options to send their newborn children. This could result in an increase of orphaned children and/or a decrease in resources for the children of large families. This would ultimately stifle the childrens and the communitys growth.
In the US, the pineapple has emerged as a symbol of IVF users, possibly because some people thought, without scientific evidence, that eating pineapple might slightly increase the success rate for the procedure. | 1 | Cryobiology |
Widespread interest and funding for research on regenerative medicine has prompted institutions in the United States and around the world to establish departments and research institutes that specialize in regenerative medicine including: The Department of Rehabilitation and Regenerative Medicine at Columbia University, the Institute for Stem Cell Biology and Regenerative Medicine at Stanford University, the Center for Regenerative and Nanomedicine at Northwestern University, the Wake Forest Institute for Regenerative Medicine, and the British Heart Foundation Centers of Regenerative Medicine at the University of Oxford. In China, institutes dedicated to regenerative medicine are run by the Chinese Academy of Sciences, Tsinghua University, and the Chinese University of Hong Kong, among others. | 2 | Tissue Engineering |
Certain perfusates have been shown to have toxic effects on kidneys as a result of the inadvertent inclusion of particular chemicals in their formulation. Collins showed that the procaine included in the formulation of his flush fluids could be toxic, and Pegg has commented how toxic materials, such as PVC plasticizers, may be washed out of perfusion circuit tubing. Dvorak showed that the methyl-prednisolone addition to the perfusate that was thought to be essential by Woods might in some circumstances be harmful. He showed that with over g of methyl-prednisolone in 650 mL of perfusate (compared with 250 mg in 1 litre used by Woods) irreversible haemodynamic and structural changes were produced in the kidney after 20 hours of perfusion. There was necrosis of capillary loops, occlusion of Bowman's spaces, basement membrane thickening and endothelial cell damage. | 1 | Cryobiology |
Fluorophore molecules could be either utilized alone, or serve as a fluorescent motif of a functional system. Based on molecular complexity and synthetic methods, fluorophore molecules could be generally classified into four categories: proteins and peptides, small organic compounds, synthetic oligomers and polymers, and multi-component systems.
Fluorescent proteins GFP, YFP, and RFP (green, yellow, and red, respectively) can be attached to other specific proteins to form a fusion protein, synthesized in cells after transfection of a suitable plasmid carrier.
Non-protein organic fluorophores belong to following major chemical families:
* Xanthene derivatives: fluorescein, rhodamine, Oregon green, eosin, and Texas red
* Cyanine derivatives: cyanine, indocarbocyanine, oxacarbocyanine, thiacarbocyanine, and merocyanine
* Squaraine derivatives and ring-substituted squaraines, including Seta and Square dyes
* Squaraine rotaxane derivatives: See Tau dyes
* Naphthalene derivatives (dansyl and prodan derivatives)
* Coumarin derivatives
* Oxadiazole derivatives: pyridyloxazole, nitrobenzoxadiazole, and benzoxadiazole
* Anthracene derivatives: anthraquinones, including DRAQ5, DRAQ7, and CyTRAK Orange
* Pyrene derivatives: cascade blue, etc.
* Oxazine derivatives: Nile red, Nile blue, cresyl violet, oxazine 170, etc.
* Acridine derivatives: proflavin, acridine orange, acridine yellow, etc.
* Arylmethine derivatives: auramine, crystal violet, malachite green
* Tetrapyrrole derivatives: porphin, phthalocyanine, bilirubin
* Dipyrromethene derivatives: BODIPY, aza-BODIPY
These fluorophores fluoresce due to delocalized electrons which can jump a band and stabilize the energy absorbed. For example, benzene, one of the simplest aromatic hydrocarbons, is excited at 254 nm and emits at 300 nm. This discriminates fluorophores from quantum dots, which are fluorescent semiconductor nanoparticles.
They can be attached to proteins to specific functional groups, such as amino groups (active ester, carboxylate, isothiocyanate, hydrazine), carboxyl groups (carbodiimide), thiol (maleimide, acetyl bromide), and organic azide (via click chemistry or non-specifically (glutaraldehyde)).
Additionally, various functional groups can be present to alter their properties, such as solubility, or confer special properties, such as boronic acid which binds to sugars or multiple carboxyl groups to bind to certain cations. When the dye contains an electron-donating and an electron-accepting group at opposite ends of the aromatic system, this dye will probably be sensitive to the environment's polarity (solvatochromic), hence called environment-sensitive. Often dyes are used inside cells, which are impermeable to charged molecules; as a result of this, the carboxyl groups are converted into an ester, which is removed by esterases inside the cells, e.g., fura-2AM and fluorescein-diacetate.
The following dye families are trademark groups, and do not necessarily share structural similarities.
* CF dye (Biotium)
* DRAQ and CyTRAK probes (BioStatus)
* BODIPY (Invitrogen)
* EverFluor (Setareh Biotech)
* Alexa Fluor (Invitrogen)
* Bella Fluor (Setareh Biotech)
* DyLight Fluor (Thermo Scientific, Pierce)
* Atto and Tracy (Sigma Aldrich)
* FluoProbes (Interchim)
* Abberior Dyes (Abberior)
* DY and MegaStokes Dyes (Dyomics)
* Sulfo Cy dyes (Cyandye)
* HiLyte Fluor (AnaSpec)
* Seta, SeTau and Square Dyes (SETA BioMedicals)
* Quasar and Cal Fluor dyes (Biosearch Technologies)
* SureLight Dyes (APC, RPEPerCP, Phycobilisomes) (Columbia Biosciences)
* APC, APCXL, RPE, BPE (Phyco-Biotech, Greensea, Prozyme, Flogen)
* Vio Dyes (Miltenyi Biotec) | 0 | Luminescence |
EL works by exciting atoms by passing an electric current through them, causing them to emit photons. By varying the material being excited, the colour of the light emitted can be changed. The actual ELD is constructed using flat, opaque electrode strips running parallel to each other, covered by a layer of electroluminescent material, followed by another layer of electrodes, running perpendicular to the bottom layer. This top layer must be transparent in order to let light escape. At each intersection, the material lights, creating a pixel. | 0 | Luminescence |
A typical adult human stomach will secrete about 1.5 liters of gastric acid daily. Gastric acid secretion is produced in several steps. Chloride and hydrogen ions are secreted separately from the cytoplasm of parietal cells and mixed in the canaliculi. Gastric acid is then secreted into the lumen of the gastric gland and gradually reaches the main stomach lumen. The exact manner in which the secreted acid reaches the stomach lumen is controversial, as acid must first cross the relatively pH-neutral gastric mucus layer.
Chloride and sodium ions are secreted actively from the cytoplasm of the parietal cell into the lumen of the canaliculus. This creates a negative potential of between −40and−70mV across the parietal cell membrane that causes potassium ions and a small number of sodium ions to diffuse from the cytoplasm into the parietal cell canaliculi.
The enzyme carbonic anhydrase catalyses the reaction between carbon dioxide and water to form carbonic acid. This acid immediately dissociates into hydrogen and bicarbonate ions. The hydrogen ions leave the cell through H/K ATPase antiporter pumps.
At the same time, sodium ions are actively reabsorbed . This means that the majority of secreted K (potassium) and Na (sodium) ions return to the cytoplasm. In the canaliculus, secreted hydrogen and chloride ions mix and are secreted into the lumen of the oxyntic gland.
The highest concentration that gastric acid reaches in the stomach is 160mM in the canaliculi. This is about 3 million times that of arterial blood, but almost exactly isotonic with other bodily fluids. The lowest pH of the secreted acid is 0.8, but the acid is diluted in the stomach lumen to a pH of between 1 and 3.
There is a small continuous basal secretion of gastric acid between meals of usually less than 10mEq/hour.
There are three phases in the secretion of gastric acid which increase the secretion rate in order to digest a meal:
# The cephalic phase: Thirty percent of the total gastric acid secretions to be produced is stimulated by anticipation of eating and the smell or taste of food. This signalling occurs from higher centres in the brain through the vagus nerve (Cranial Nerve X). It activates parietal cells to release acid and ECL cells to release histamine. The vagus nerve (CN X) also releases gastrin releasing peptide onto G cells. Finally, it also inhibits somatostatin release from D cells.
# The gastric phase: About sixty percent of the total acid for a meal is secreted in this phase. Acid secretion is stimulated by distension of the stomach and by amino acids present in the food.
# The intestinal phase: The remaining 10% of acid is secreted when chyme enters the small intestine, and is stimulated by small intestine distension and by amino acids. The duodenal cells release entero-oxyntin which acts on parietal cells without affecting gastrin. | 4 | Acids + Bases |
On 17 January 2013, Russian ballet dancer Sergei Filin was attacked with acid by an unknown assailant, who cornered him outside of his home in Moscow. He suffered third-degree burns to his face and neck. While it was initially reported that he was in danger of losing his eyesight, his physicians stated on 21 January 2013, that he would retain eyesight in one eye. Three men, including dancer Dmitrichenko, were subsequently sentenced to 4–10 years of prison each for orchestrating and executing the crime. | 4 | Acids + Bases |
Salting out (also known as salt-induced precipitation, salt fractionation, anti-solvent crystallization, precipitation crystallization, or drowning out) is a purification technique that utilizes the reduced solubility of certain molecules in a solution of very high ionic strength. Salting out is typically used to precipitate large biomolecules, such as proteins or DNA. Because the salt concentration needed for a given protein to precipitate out of the solution differs from protein to protein, a specific salt concentration can be used to precipitate a target protein. This process is also used to concentrate dilute solutions of proteins. Dialysis can be used to remove the salt if needed. | 5 | Separation Processes |
The compound has been prepared in a multistep process starting with the base hydrolysis of phosphorus pentasulfide to give dithiophosphate, which is isolated as its barium salt:
In a second stage, the barium salt is decomposed with sulfuric acid, precipitating barium sulfate and liberating free dithiophosphoric acid:
Under controlled conditions, dithiophosphoric acid hydrolyses to give the monothioderivative: | 4 | Acids + Bases |
The function of lectins in plants (legume lectin) is still uncertain. Once thought to be necessary for rhizobia binding, this proposed function was ruled out through lectin-knockout transgene studies.
The large concentration of lectins in plant seeds decreases with growth, and suggests a role in plant germination and perhaps in the seed's survival itself. The binding of glycoproteins on the surface of parasitic cells also is believed to be a function. Several plant lectins have been found to recognize noncarbohydrate ligands that are primarily hydrophobic in nature, including adenine, auxins, cytokinin, and indole acetic acid, as well as water-soluble porphyrins. These interactions may be physiologically relevant, since some of these molecules function as phytohormones.
Lectin receptor kinases (LecRKs) are believed to recognize damage associated molecular patterns (DAMPs), which are created or released from herbivore attack. In Arabidopsis, legume-type LecRKs Clade 1 has 11 LecRK proteins. LecRK-1.8 has been reported to recognize extracellular NAD molecules and LecRK-1.9 has been reported to recognize extracellular ATP molecules. | 6 | Carbohydrates |
The integrability is underpinned by the existence of large symmetry algebras for the different models. For the XXX case this is the Yangian , while in the XXZ case this is the quantum group , the q-deformation of the affine Lie algebra of , as explained in the notes by .
These appear through the transfer matrix, and the condition that the Bethe vectors are generated from a state satisfying corresponds to the solutions being part of a highest-weight representation of the extended symmetry algebras. | 7 | Magnetic Ordering |
The degree of inactivation by ultraviolet radiation is directly related to the UV dose applied to the water. The dosage, a product of UV light intensity and exposure time, is usually measured in microjoules per square centimeter, or equivalently as microwatt seconds per square centimeter (μW·s/cm) = 10 mW·s/m = 0.01 W·s/m, the latter might be better, giving two-digit values for the ones in this article-->. Dosages for a 90% kill of most bacteria and viruses range between 2,000 and 8,000 μW·s/cm. Larger parasites such as Cryptosporidium require a lower dose for inactivation. As a result, US EPA has accepted UV disinfection as a method for drinking water plants to obtain Cryptosporidium, Giardia or virus inactivation credits. For example, for a 90% reduction of Cryptosporidium, a minimum dose of 2,500 μW·s/cm is required based on EPA's 2006 guidance manual. | 8 | Ultraviolet Radiation |
In the early 1900s, Werner Spalteholz developed a technique that allowed the clarification of large tissues, using Wintergrünöl (methyl salicylate) and benzyl benzoate. Over the next hundred years, various scientists introduced their own variations on Spalteholzs technique. Tuchin et al. introduced TOC in 1997, adding a new branch of tissue clearing that was hydrophilic instead of hydrophobic like Spalteholzs technique. In 2007, Dodt et al. developed a two step process, wherein tissues were first dehydrated with ethanol and hexane and subsequently made transparent by immersion in benzyl alcohol and benzyl benzoate (BABB), a technique they coupled with light sheet fluorescence microscopy. Hama et al. developed another hydrophilic approach, Scale, in 2011. The following year, Ertürk et al. developed a hydrophobic approach called 3DISCO, in which they pretreated tissue with tetrahydrofuran and dichloromethane before clearing it in dibenzyl ether. A year later, in 2013, Chung et al. developed CLARITY, the first approach to use hydrogel monomers to clear tissue. | 2 | Tissue Engineering |
TTM has been studied in several use scenarios where it has not usually been found to be helpful, or is still under investigation, despite theoretical grounds for its usefulness. | 1 | Cryobiology |
Organ printing technology can also be combined with microfluidic technology to develop organs-on-chips. These organs-on-chips have the potential to be used for disease models, aiding in drug discovery, and performing high-throughput assays. Organ-on-chips work by providing a 3D model that imitates the natural extracellular matrix, allowing them to display realistic responses to drugs. Thus far, research has been focused on developing liver-on-a-chip and heart-on-a-chip, but there exists the potential to develop an entire body-on-a-chip model.
By combining 3D printed organs, researchers are able to create a body-on-a-chip. The heart-on-a-chip model has already been used to investigate how several drugs with heart rate-based negative side effects, such as the chemotherapeutic drug doxorubicin could affect people on an individual basis. The new body-on-a-chip platform includes liver, heart, lungs, and kidney-on-a-chip. The organs-on-a-chip are separately printed or constructed and then integrated together. Using this platform drug toxicity studies are performed in high throughput, lowering the cost and increasing the efficiency in the drug-discovery pipeline. | 2 | Tissue Engineering |
Trinitromethane as a neutral molecule is colorless. It is highly acidic, easily forming an intensely yellow anion, (NO)C. The pK of trinitromethane has been measured at 0.17 ± 0.02 at 20 °C, which is remarkably acidic for a methane derivative. Trinitromethane easily dissolves in water to form an acidic yellow solution.
There is some evidence that the anion, which obeys the 4n+2 Hückel rule, is aromatic. | 4 | Acids + Bases |
Accelerator-based light-ion fusion is a technique using particle accelerators to achieve particle kinetic energies sufficient to induce light-ion fusion reactions.
Accelerating light ions is relatively easy, and can be done in an efficient manner—requiring only a vacuum tube, a pair of electrodes, and a high-voltage transformer; fusion can be observed with as little as 10 kV between the electrodes. The system can be arranged to accelerate ions into a static fuel-infused target, known as beam–target fusion, or by accelerating two streams of ions towards each other, beam–beam fusion. The key problem with accelerator-based fusion (and with cold targets in general) is that fusion cross sections are many orders of magnitude lower than Coulomb interaction cross-sections. Therefore, the vast majority of ions expend their energy emitting bremsstrahlung radiation and the ionization of atoms of the target. Devices referred to as sealed-tube neutron generators are particularly relevant to this discussion. These small devices are miniature particle accelerators filled with deuterium and tritium gas in an arrangement that allows ions of those nuclei to be accelerated against hydride targets, also containing deuterium and tritium, where fusion takes place, releasing a flux of neutrons. Hundreds of neutron generators are produced annually for use in the petroleum industry where they are used in measurement equipment for locating and mapping oil reserves.
A number of attempts to recirculate the ions that "miss" collisions have been made over the years. One of the better-known attempts in the 1970s was Migma, which used a unique particle storage ring to capture ions into circular orbits and return them to the reaction area. Theoretical calculations made during funding reviews pointed out that the system would have significant difficulty scaling up to contain enough fusion fuel to be relevant as a power source. In the 1990s, a new arrangement using a field-reverse configuration (FRC) as the storage system was proposed by Norman Rostoker and continues to be studied by TAE Technologies . A closely related approach is to merge two FRC's rotating in opposite directions, which is being actively studied by Helion Energy. Because these approaches all have ion energies well beyond the Coulomb barrier, they often suggest the use of alternative fuel cycles like p-B that are too difficult to attempt using conventional approaches. | 3 | Nuclear Fusion |
DSSCs are currently the most efficient third-generation (2005 Basic Research Solar Energy Utilization 16) solar technology available. Other thin-film technologies are typically between 5% and 13%, and traditional low-cost commercial silicon panels operate between 14% and 17%. This makes DSSCs attractive as a replacement for existing technologies in "low density" applications like rooftop solar collectors, where the mechanical robustness and light weight of the glass-less collector is a major advantage. They may not be as attractive for large-scale deployments where higher-cost higher-efficiency cells are more viable, but even small increases in the DSSC conversion efficiency might make them suitable for some of these roles as well.
There is another area where DSSCs are particularly attractive. The process of injecting an electron directly into the TiO is qualitatively different from that occurring in a traditional cell, where the electron is "promoted" within the original crystal. In theory, given low rates of production, the high-energy electron in the silicon could re-combine with its own hole, giving off a photon (or other form of energy) which does not result in current being generated. Although this particular case may not be common, it is fairly easy for an electron generated by another atom to combine with a hole left behind in a previous photoexcitation.
In comparison, the injection process used in the DSSC does not introduce a hole in the TiO, only an extra electron. Although it is energetically possible for the electron to recombine back into the dye, the rate at which this occurs is quite slow compared to the rate that the dye regains an electron from the surrounding electrolyte. Recombination directly from the TiO to species in the electrolyte is also possible although, again, for optimized devices this reaction is rather slow. On the contrary, electron transfer from the platinum coated electrode to species in the electrolyte is necessarily very fast.
As a result of these favorable "differential kinetics", DSSCs work even in low-light conditions. DSSCs are therefore able to work under cloudy skies and non-direct sunlight, whereas traditional designs would suffer a "cutout" at some lower limit of illumination, when charge carrier mobility is low and recombination becomes a major issue. The cutoff is so low they are even being proposed for indoor use, collecting energy for small devices from the lights in the house.
A practical advantage which DSSCs share with most thin-film technologies, is that the cell's mechanical robustness indirectly leads to higher efficiencies at higher temperatures. In any semiconductor, increasing temperature will promote some electrons into the conduction band "mechanically". The fragility of traditional silicon cells requires them to be protected from the elements, typically by encasing them in a glass box similar to a greenhouse, with a metal backing for strength. Such systems suffer noticeable decreases in efficiency as the cells heat up internally. DSSCs are normally built with only a thin layer of conductive plastic on the front layer, allowing them to radiate away heat much easier, and therefore operate at lower internal temperatures. | 8 | Ultraviolet Radiation |
The calculation of excess heat in electrochemical cells involves certain assumptions. Errors in these assumptions have been offered as non-nuclear explanations for excess heat.
One assumption made by Fleischmann and Pons is that the efficiency of electrolysis is nearly 100%, meaning nearly all the electricity applied to the cell resulted in electrolysis of water, with negligible resistive heating and substantially all the electrolysis product leaving the cell unchanged. This assumption gives the amount of energy expended converting liquid DO into gaseous D and O. The efficiency of electrolysis is less than one if hydrogen and oxygen recombine to a significant extent within the calorimeter. Several researchers have described potential mechanisms by which this process could occur and thereby account for excess heat in electrolysis experiments.
Another assumption is that heat loss from the calorimeter maintains the same relationship with measured temperature as found when calibrating the calorimeter. This assumption ceases to be accurate if the temperature distribution within the cell becomes significantly altered from the condition under which calibration measurements were made. This can happen, for example, if fluid circulation within the cell becomes significantly altered. Recombination of hydrogen and oxygen within the calorimeter would also alter the heat distribution and invalidate the calibration. | 3 | Nuclear Fusion |
Hypothermia can happen in most mammals in cold weather and can be fatal. Baby mammals such as kittens are unable to regulate their body temperatures and have a risk of hypothermia if they are not kept warm by their mothers.
Many animals other than humans often induce hypothermia during hibernation or torpor.
Water bears (Tardigrade), microscopic multicellular organisms, can survive freezing at low temperatures by replacing most of their internal water with the sugar trehalose, preventing the crystallization that otherwise damages cell membranes. | 1 | Cryobiology |
Bussard worked on a promising new type of inertial electrostatic confinement (IEC) fusor, called the Polywell, that has a magnetically shielded grid (MaGrid). He founded Energy/Matter Conversion Corporation, Inc. (EMC2) in 1985 to validate his theory, and tested several (15) experimental devices from 1994 through 2006. The U.S. Navy contract funding that supported the work expired while experiments were still small. However, the final tests of the last device, WB-6, reputedly solved the last remaining physics problem just as the funding expired and the EMC2 labs had to be shut down.
Further funding was eventually found, the work continued and the WB-7 prototype was constructed and tested, and the research is ongoing. | 3 | Nuclear Fusion |
With the advancement of tissue engineering an alternative approach was developed: the full-thickness engineered oral mucosa. Full-thickness engineered oral mucosa is a better simulation of the in vivo situation because they take the anatomical structure of native oral mucosa into account. Problems, such as tissue shortage and donor site morbidity, do not occur when using full-thickness engineered oral mucosa.
The main goal when producing full-thickness engineered oral mucosa is to make it resemble normal oral mucosa as much as possible. This is achieved by using a combination of different cell types and scaffolds.
* Lamina propria: is mimicked by seeding oral fibroblasts, producing extracellular matrix, into a biocompatible (porous) scaffold and culturing them in a fibroblast differentiation medium.
* Basement membrane: containing type IV collagen, laminin, fibronectin and integrins. Ideally, the basement membrane must contain a lamina lucida and a lamina densa.
* Stratified squamous epithelium: is simulated by oral keratinocytes cultured in a medium containing keratinocyte growth factors such as the epidermal growth factor (EGF).
To obtain the best results, the type and origin of the fibroblasts and keratinocytes used in oral mucosa tissue engineering are important factors to hold into account. Fibroblasts are usually taken from the dermis of the skin or oral mucosa. Kertinocytes can be isolated from different areas of the oral cavity (such as the palate or gingiva). It is important that the fibroblasts and keratinocytes are used in the earliest stage possible as the function of these cells decreases with time. The transplanted keratinocytes and fibroblasts should adapt to their new environment and adopt their function. There is a risk of losing the transplanted tissue if the cells do not adapt properly. This adaptation goes more smoothly when the donor tissue cells resemble the cells of the native tissue. | 2 | Tissue Engineering |
The Polder tensor is a tensor introduced by Dirk Polder for the description of magnetic permeability of ferrites. The tensor notation needs to be used because ferrimagnetic material becomes anisotropic in the presence of a magnetizing field.
The tensor is described mathematically as:
Neglecting the effects of damping, the components of the tensor are given by
where
(rad / s) / (A / m) is the effective gyromagnetic ratio and , the so-called effective g-factor (physics), is a ferrite material constant typically in the range of 1.5 - 2.6, depending on the particular ferrite material. is the frequency of the RF/microwave signal propagating through the ferrite, is the internal magnetic bias field, is the magnetization of the ferrite material and is the magnetic permeability of free space.
To simplify computations, the radian frequencies of and can be replaced with frequencies (Hz) in the equations for and because the factor cancels. In this case, Hz / (A / m) MHz / Oe. If CGS units are used, computations can be further simplified because the factor can be dropped. | 7 | Magnetic Ordering |
This timeline of nuclear fusion is an incomplete chronological summary of significant events in the study and use of nuclear fusion. | 3 | Nuclear Fusion |
After collection, sperm must be processed for storage. According to the Sperm Bank of California, sperm banks and clinics can use the unwashed or wash method to process sperm samples. The wash method includes removing unwanted particles and adding buffer solutions to preserve viable sperm. However, this approach can contribute to further stress on the sperm cells and decrease the survival of sperm after freezing. The unwashed approach allows for more flexibility to freeze the semen sample and increases the number of sperm survival. One sample can produce 1–20 vials or straws, depending on the quantity of the ejaculate and whether the sample is washed or unwashed. Unwashed samples are used for intracervical insemination (ICI) treatments, and washed samples are used in intrauterine insemination (IUI) and for in-vitro fertilization (IVF) or assisted reproduction technologies (ART) procedures.
A cryoprotectant semen extender is conducted if the semen sample is placed in the freezer for storage. Semen extenders play a key factor in protecting sperm sample from freeze and osmotic shock, oxidative stress, and cell injury due to the formation of ice crystal during frozen storage. The collection of semen is preserved by stabilizing the properties of the sperm cells such as the membrane, motility, and DNA integrity in order to create a sustainable viable environment. There are two common forms of medium for sperm cyropreservation, one containing of egg yolk from hens and glycerol, and the other containing just glycerol. One study compared media supplemented with egg yolk and media supplemented with soy lecithin, finding that there was no significance between sperm motility, morphology, chromatin decondensation, or binding between the two, indicating that soy lecithin may be a viable alternative to egg yolk. | 1 | Cryobiology |
Sublimation is a technique used by chemists to purify compounds. A solid is typically placed in a sublimation apparatus and heated under vacuum. Under this reduced pressure, the solid volatilizes and condenses as a purified compound on a cooled surface (cold finger), leaving a non-volatile residue of impurities behind. Once heating ceases and the vacuum is removed, the purified compound may be collected from the cooling surface.
For even higher purification efficiencies, a temperature gradient is applied, which also allows for the separation of different fractions. Typical setups use an evacuated glass tube that is heated gradually in a controlled manner. The material flow is from the hot end, where the initial material is placed, to the cold end that is connected to a pump stand. By controlling temperatures along the length of the tube, the operator can control the zones of re-condensation, with very volatile compounds being pumped out of the system completely (or caught by a separate cold trap), moderately volatile compounds re-condensing along the tube according to their different volatilities, and non-volatile compounds remaining in the hot end.
Vacuum sublimation of this type is also the method of choice for purification of organic compounds for use in the organic electronics industry, where very high purities (often > 99.99%) are needed to satisfy the standards for consumer electronics and other applications. | 5 | Separation Processes |
According to a study done by the Mayo Clinic, miscarriage rates for IVF are somewhere between 15 and 25% for those under the age of 35. In naturally conceived pregnancies, the rate of miscarriage is between 10 and 20% for those under the age of 35. Risk of miscarriage, regardless of the method of conception, does increase with age. | 1 | Cryobiology |
The uncontrollable transfer of a molecular "ink" from a coated AFM tip to a substrate was first reported by Jaschke and Butt in 1995, but they erroneously concluded that alkanethiols could not be transferred to gold substrates to form stable nanostructures. A research group at Northwestern University, US led by Chad Mirkin independently studied the process and determined that under the appropriate conditions, molecules could be transferred to a wide variety of surfaces to create stable chemically-adsorbed monolayers in a high resolution lithographic process they termed "DPN". Mirkin and his coworkers hold the patents on this process, and the patterning technique has expanded to include liquid "inks". It is important to note that "liquid inks" are governed by a very different deposition mechanism when compared to "molecular inks". | 2 | Tissue Engineering |
Vitrification is the progressive partial fusion of a clay, or of a body, as a result of a firing process. As vitrification proceeds, the proportion of glassy bond increases and the apparent porosity of the fired product becomes progressively lower. Vitreous bodies have open porosity, and may be either opaque or translucent. In this context, "zero porosity" may be defined as less than 1% water absorption. However, various standard procedures define the conditions of water absorption. An example is by ASTM, who state "The term vitreous generally signifies less than 0.5% absorption, except for floor and wall tile and low-voltage electrical insulators, which are considered vitreous up to 3% water absorption."
Pottery can be made impermeable to water by glazing or by vitrification. Porcelain, bone china, and sanitaryware are examples of vitrified pottery, and are impermeable even without glaze. Stoneware may be vitrified or semi-vitrified; the latter type would not be impermeable without glaze. | 1 | Cryobiology |
A sperm bank will aim to provide donor sperm which is safe by checking and screening donors and of their semen. A sperm donor must generally meet specific requirements regarding age and medical history. Requirements for sperm donors are strictly enforced, as in a study of 24,040 potential sperm donors, only 5620, or 23.38% were eligible to donate their sperm.
Sperm banks typically screen potential donors for a range of diseases and disorders, including genetic diseases, chromosomal abnormalities and sexually transmitted infections that may be transmitted through sperm. The screening procedure generally also includes a quarantine period, in which the samples are frozen and stored for at least six months after which the donor will be re-tested for the STIs. This is to ensure no new infections have been acquired or have developed during the period of donation. Providing the result is negative, the sperm samples can be released from quarantine and used in treatments. Common reasons for sperm rejection include suboptimal semen quality and STDs. Chromosomal abnormalities are also a cause for semen rejection, but are less common. Children conceived through sperm donation have a birth defect rate of almost a fifth compared with the general population.
A sperm bank takes a number of steps to ensure the health and quality of the sperm which it supplies and it will inform customers of the checks which it undertakes, providing relevant information about individual donors. A sperm bank will usually guarantee the quality and number of motile sperm available in a sample after thawing. They will try to select men as donors who are particularly fertile and whose sperm will survive the freezing and thawing process. Samples are often sold as containing a particular number of motile sperm per milliliter, and different types of samples may be sold by a sperm bank for differing types of use, e.g. ICI or IUI.
The sperm will be checked to ensure its fecundity and also to ensure that motile sperm will survive the freezing process. If a man is accepted onto the sperm banks program as a sperm donor, his sperm will be constantly monitored, the donor will be regularly checked for infectious diseases, and samples of his blood will be taken at regular intervals. A sperm bank may provide a donor with dietary supplements containing herbal or mineral substances such as maca, zinc, vitamin E and arginine which are designed to improve the quality and quantity of the donors semen, as well as reducing the refractory time (i.e. the time between viable ejaculations). All sperm is frozen in straws or vials and stored for as long as the sperm donor may and can maintain it.
Donors are subject to tests for infectious diseases such as human immunoviruses HIV (HIV-1 and HIV-2), human T-cell lymphotropic viruses (HTLV-1 and HTLV-2), syphilis, chlamydia, gonorrhea, hepatitis B virus, hepatitis C virus, cytomegalovirus (CMV), Trypanosoma cruzi and malaria as well as hereditary diseases such as cystic fibrosis, Sickle cell anemia, Familial Mediterranean fever, Gauchers disease, thalassaemia, Tay–Sachs disease, Canavans disease, familial dysautonomia, congenital adrenal hyperplasia, carnitine transporter deficiency and Karyotyping 46XY. Karyotyping is not a requirement in either EU or the US but some sperm banks choose to test donors as an extra service to the customer.
A sperm donor may also be required to produce their medical records and those of their family, often for several generations. A sperm sample is usually tested micro-biologically at the sperm bank before it is prepared for freezing and subsequent use. A sperm donor's blood group may also be registered to ensure compatibility with the recipient.
Some sperm banks may disallow sexually active gay men from donating sperm due to the population's increased risk of HIV and hepatitis B. Modern sperm banks have also been known to screen out potential donors based on genetic conditions and family medical history. | 1 | Cryobiology |
A cathodoluminescence (CL) microscope combines a regular (light optical) microscope with a cathode-ray tube. It is designed to image the luminescence characteristics of polished thin sections of solids irradiated by an electron beam.
Using a cathodoluminescence microscope, structures within crystals or fabrics can be made visible which cannot be seen in normal light conditions. Thus, for example, valuable information on the growth of minerals can be obtained. CL-microscopy is used in geology, mineralogy and materials science for the investigation of rocks, minerals, volcanic ash, glass, ceramic, concrete, fly ash, etc.
CL color and intensity are dependent on the characteristics of the sample and on the working conditions of the electron gun. Here, acceleration voltage and beam current of the electron beam are of major importance. Today, two types of CL microscopes are in use. One is working with a "cold cathode" generating an electron beam by a corona discharge tube, the other one produces a beam using a "hot cathode". Cold-cathode CL microscopes are the simplest and most economical type. Unlike other electron bombardment techniques like electron microscopy, cold cathodoluminescence microscopy provides positive ions along with the electrons which neutralize surface charge buildup and eliminate the need for conductive coatings to be applied to the specimens. The "hot cathode" type generates an electron beam by an electron gun with tungsten filament. The advantage of a hot cathode is the precisely controllable high beam intensity allowing to stimulate the emission of light even on weakly luminescing materials (e.g. quartz – see picture). To prevent charging of the sample, the surface must be coated with a conductive layer of gold or carbon. This is usually done by a sputter deposition device or a carbon coater. | 0 | Luminescence |
The effective field is the local field felt by the magnetization. It can be described informally as the derivative of the magnetic energy density with respect to the orientation of the magnetization, as in:
where dE/dV is the energy density. In variational terms, a change dm of the magnetization and the associated change dE of the magnetic energy are related by:
Since m is a unit vector, dm is always perpendicular to m. Then the above definition leaves unspecified the component of H that is parallel to m. This is usually not a problem, as this component has no effect on the magnetization dynamics.
From the expression of the different contributions to the magnetic energy, the effective field can be found to be: | 7 | Magnetic Ordering |
In 1960, Bussard conceived of the Bussard ramjet, an interstellar space drive powered by hydrogen fusion using hydrogen collected with a magnetic field from the interstellar gas. Due to the presence of high-energy particles throughout space, much of the interstellar hydrogen exists in an ionized state (H II regions) that can be manipulated by magnetic or electric fields. Bussard proposed to "scoop" up ionized hydrogen and funnel it into a fusion reactor, using the exhaust from the reactor as a rocket engine.
It appears the energy gain in the reactor must be extremely high for the ramjet to work at all; any hydrogen picked up by the scoop must be sped up to the same speed as the ship in order to provide thrust, and the energy required to do so increases with the ship's speed. Hydrogen itself does not fuse very well (unlike deuterium, which is rare in the interstellar medium), and so cannot be used directly to produce energy, a fact which accounts for the billion-year scale of stellar lifetimes. This problem was solved, in principle, according to Bussard by use of the stellar CNO cycle in which carbon is used as a catalyst to burn hydrogen via the strong nuclear reaction. | 3 | Nuclear Fusion |
This formulation allows the study of the motions and the effects of heat conduction, shear viscosity, compressibility, and surface tension on small cavitation bubbles in liquids that are set into motion by an acoustic pressure field. The effect of vapor pressure on the cavitation bubble can also be determined using the interfacial temperature. The formulation is specifically designed to describe the motion of a bubble that expands to a maximum radius and then violently collapses or contracts. This set of equations was solved using an improved Euler method.
where is the radius of the bubble, the dots indicate first and second time derivatives, is the density of the liquid, is the speed of sound through the liquid, is the pressure on the liquid side of the bubble's interface, is time, and is the driving pressure. | 0 | Luminescence |
Fibroblast-populated Skin Substitutes are scaffolds which contain fibroblasts that are able to proliferate and produce extracellular matrix and growth factors within 2 to 3 weeks. This creates a matrix similar to that of a dermis.
Commercially available types are for example:
* Dermagraft
* Apligraf
* Orcel
* Polyactive
* Hyalograf 3D | 2 | Tissue Engineering |
DEHPA can be used to extract lanthanides (rare earths) from aqeuous solutions, it is commonly used in the lanthanide sector as an extraction agent. In general the distribution ratio of the lanthanides increase as their atomic number increases due to the lanthanide contraction. It is possible by bringing a mixture of lanthanides in a counter current mixer settler bank into contact with a suitable concentration of nitric acid to selectively strip (back extract) some of the lanthanides while leaving the others still in the DEHPA based organic layer. In this way selective stripping of the lanthanides can be used to make a separation of a mixture of the lanthanides into mixtures containing fewer lanthanides. Under ideal conditions this can be used to obtain a single lanthanide from a mixture of many lanthanides.
It is common to use DEHPA in an aliphatic kerosene which is best considered to be a mixture of long chain alkanes and cycloalkanes. When used in an aromatic hydrocarbon diluent the lanthanide distribution ratios are lower. It has been shown that it is possible to use a second generation biodiesel which was made by the hydrotreatment of vegetable oil. It has been reported that Neste's HVO100 is a suitable diluent for DEHPA when calcium, lanthanum and neodymium are extracted from aqueous nitric acid | 5 | Separation Processes |
Lectins are carbohydrate-binding proteins that are highly specific for sugar groups that are part of other molecules, so cause agglutination of particular cells or precipitation of glycoconjugates and polysaccharides. Lectins have a role in recognition at the cellular and molecular level and play numerous roles in biological recognition phenomena involving cells, carbohydrates, and proteins. Lectins also mediate attachment and binding of bacteria, viruses, and fungi to their intended targets.
Lectins are found in many foods. Some foods, such as beans and grains, need to be cooked, fermented or sprouted to reduce lectin content. Some lectins are beneficial, such as CLEC11A, which promotes bone growth, while others may be powerful toxins such as ricin.
Lectins may be disabled by specific mono- and oligosaccharides, which bind to ingested lectins from grains, legumes, nightshade plants, and dairy; binding can prevent their attachment to the carbohydrates within the cell membrane. The selectivity of lectins means that they are useful for analyzing blood type, and they have been researched for potential use in genetically engineered crops to transfer pest resistance. | 6 | Carbohydrates |
Cryosurgery is also used to treat internal and external tumors as well as tumors in the bone. To cure internal tumors, a hollow instrument called a cryoprobe is used, which is placed in contact with the tumor. Liquid nitrogen or argon gas is passed through the cryoprobe. Ultrasound or MRI is used to guide the cryoprobe and monitor the freezing of the cells. This helps in limiting damage to adjacent healthy tissues. A ball of ice crystals forms around the probe which results in freezing of nearby cells. When it is required to deliver gas to various parts of the tumor, more than one probe is used. After cryosurgery, the frozen tissue is either naturally absorbed by the body in the case of internal tumors, or it dissolves and forms a scab for external tumors. | 1 | Cryobiology |
Fusion Nuclear Science Facility (FNSF) is a low cost, low aspect ratio compact tokamak reactor design, aiming for a 9 Tesla field at the plasma centre.
It is considered a step after ITER on the path to a fusion power plant.
Because of the high neutron irradiation damage expected, non-insulating superconducting coils are being considered for it. | 3 | Nuclear Fusion |
RiAFP refers to an antifreeze protein (AFP) produced by the Rhagium inquisitor longhorned beetle. It is a type V antifreeze protein with a molecular weight of 12.8 kDa; this type of AFP is noted for its hyperactivity. R. inquisitor is a freeze-avoidant species, meaning that, due to its AFP, R. inquisitor prevents its body fluids from freezing altogether. This contrasts with freeze-tolerant species, whose AFPs simply depress levels of ice crystal formation in low temperatures. Whereas most insect antifreeze proteins contain cysteines at least every sixth residue, as well as varying numbers of 12- or 13-mer repeats of 8.3-12.5kDa, RiAFP is notable for containing only one disulfide bridge. This property of RiAFP makes it particularly attractive for recombinant expression and biotechnological applications. | 1 | Cryobiology |