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All skimmers have key features in common: water flows through a chamber and is brought into contact with a column of fine bubbles. The bubbles collect proteins and other substances and carry them to the top of the device where the foam, but not the water, collects in a cup. Here the foam condenses to a liquid, which can be easily removed from the system. The material that collects in the cup can range from pale greenish-yellow, watery liquid to a thick black tar.
Consider this summary of optimal protein skimmer design by Randy Holmes-Farley:
Also under considerable recent attention has been the general shape of a skimmer as well. In particular, much attention has been given to the introduction of cone shaped skimmer units. Originally designed by Klaus Jensen in 2004, the concept was founded on the principle that a conical body allows the foam to accumulate more steadily through a gently sloping transition. It was claimed that this reduces the overall turbulence, resulting in more efficient skimming. However, this design reduces the overall volume inside the skimmer, reducing dwell time. Cylindrical-shaped protein skimmers are the most popular design and allow for the largest volume of air and water.
Overall, protein skimmers can be classed in two ways depending on whether they operate by co-current flow or counter-current flow. In a co-current flow system, air is introduced at the bottom of the chamber and is in contact with the water as it rises upwards towards the collection chamber. In a counter-current system, air is forced into the system under pressure and moves against the flow of the water for a while before it rises up towards the collection cup. Because the air bubbles may be in contact with the water for a longer period in a counter-current flow system, protein skimmers of this type are considered by some to be more effective at removing organic wastes. | 5 | Separation Processes |
Under Lavoisiers original theory, all acids contained oxygen, which was named from the Greek ὀξύς (oxys: acid, sharp) and the root -γενής (-genes': creator). It was later discovered that some acids, notably hydrochloric acid, did not contain oxygen and so acids were divided into oxo-acids and these new hydroacids.
All oxyacids have the acidic hydrogen bound to an oxygen atom, so bond strength (length) is not a factor, as it is with binary nonmetal hydrides. Rather, the electronegativity of the central atom and the number of oxygen atoms determine oxyacid acidity. For oxyacids with the same central atom, acid strength increases with the number of oxygen atoms attached to it. With the same number of oxygen atoms attached to it, acid strength increases with increasing electronegativity of the central atom.
Compared to the salts of their deprotonated forms (a class of compounds known as the oxyanions), oxyacids are generally less stable, and many of them only exist formally as hypothetical species, or only exist in solution and cannot be isolated in pure form. There are several general reasons for this: (1) they may condense to form oligomers (e.g., HCrO to HCrO), or dehydrate all the way to form the anhydride (e.g., HCO to CO), (2) they may disproportionate to one compound of higher and another of lower oxidation state (e.g., HClO to HClO and HClO), or (3) they might exist almost entirely as another, more stable tautomeric form (e.g., phosphorous acid P(OH) exists almost entirely as phosphonic acid HP(=O)(OH)). Nevertheless, perchloric acid (HClO), sulfuric acid (HSO), and nitric acid (HNO) are a few common oxyacids that are relatively easily prepared as pure substances.
Imidic acids are created by replacing =O with =NR in an oxyacid. | 4 | Acids + Bases |
The use of glucosinolate-containing crops as primary food source for animals can have negative effects if the concentration of glucosinolate is higher than what is acceptable for the animal in question, because some glucosinolates have been shown to have toxic effects (mainly as goitrogens and anti-thyroid agents) in livestock at high doses. However, tolerance level to glucosinolates varies even within the same genus (e.g. Acomys cahirinus and Acomys russatus).
Dietary amounts of glucosinolate are not toxic to humans given normal iodine intake. | 6 | Carbohydrates |
The limit for the ambient size of the bubble is set by the appearance of instabilities in the shape of the oscillating bubble.
The shape stability thresholds depend on changes in the radial dynamics, caused by different liquid viscosities or driving frequencies. If the frequency is decreased, the parametric instability is suppressed as the stabilizing influence of viscosity can appear longer to suppress perturbations. However, the collapses of low-frequency-driven bubbles favor an earlier onset of the Rayleigh-Taylor instability. Larger bubbles can be stabilized to show sonoluminescence when not too high forcing pressures are applied. At low-frequency the water vapor becomes more important. The bubbles can be stabilized by cooling the fluid, whereas more light is emitted. | 0 | Luminescence |
The membrane assembly consists of a pressure vessel with a membrane that allows feedwater to be pushed against it. The membrane must be strong enough to withstand the pressure. RO membranes are made in a variety of configurations. The two most common are spiral-wound and hollow-fiber.
Only part of the water pumped onto the membrane passes through. The left-behind "concentrate" passes along the saline side of the membrane and flushes away the salt and other remnants. The percentage of desalinated water is the "recovery ratio". This varies with salinity and system design parameters: typically 20% for small seawater systems, 40% – 50% for larger seawater systems, and 80% – 85% for brackish water. The concentrate flow is typically 3 bar/50 psi less than the feed pressure, and thus retains much of the input energy.
The desalinated water purity is a function of the feed water salinity, membrane selection and recovery ratio. To achieve higher purity a second pass can be added which generally requires another pumping cycle. Purity expressed as total dissolved solids typically varies from 100 to 400 parts per million (ppm or mg/litre) on a seawater feed. A level of 500 ppm is generally the upper limit for drinking water, while the US Food and Drug Administration classifies mineral water as water containing at least 250 ppm. | 5 | Separation Processes |
Classification of nerve damage was well-defined by Sir Herbert Seddon and Sunderland in a system that remains in use. The adjacent table details the forms (neurapraxia, axonotmesis and neurotmesis) and degrees of nerve injury that occur as a result of exposure to various temperatures.
Cryoneurolysis treatments that use nitrous oxide (boiling point of −88.5 °C) as the coolant fall in the range of an axonotmesis injury, or 2nd degree injury, according to the Sunderland classification system. Treatments of the nerve in this temperature range are reversible. Nerves treated in this temperature range experience a disruption of the axon, with Wallerian degeneration occurring distal to the site of injury. The axon and myelin sheath are affected, but all of the connective tissues (endoneurium, perineurium, and epineurium) remain intact. Following Wallerian degeneration, the axon regenerates along the original nerve path at a rate of approximately 1–2 mm per day.
Cryoneurolysis differs from cryoablation in that cryoablation treatments utilize liquid nitrogen (boiling point of −195.8 °C) as the coolant, and therefore, fall into the range of a neurotmesis injury, or 3rd degree injury according to the Sunderland classification. Treatments of the nerve in this temperature range are irreversible. Nerves treated in this temperature range experience a disruption of both the axon and the endoneurium connective tissue layer. | 1 | Cryobiology |
PSCs-derived cells from patients are used in vitro to recreate specific pathologies. The specific cell type affected in the pathology is at the base of the model. For example, motoneurons are used to study spinal muscular atrophy (SMA) and cardiomyocytes are used to study arrythmia. This can allow for a better understanding of the pathogenesis and the development of new treatments through drug discovery. Immature PSC-derived cell types can be matured in vitro by various strategies, such as in vitro ageing, to modelize age-related disease in vitro.
Major diseases being modelized with PSCs-derived cells are amyotrophic lateral sclerosis (ALS), Alzheimers (AD), Parkinsons (PD), fragile X syndrome (FXS), Huntington disease (HD), Down syndrome, Spinal muscular atrophy (SMA), muscular dystrophies, cystic fibrosis, Long QT syndrome, and Type I diabetes. | 2 | Tissue Engineering |
Molecular inks are typically composed of small molecules that are coated onto a DPN tip and are delivered to the surface through a water meniscus. In order to coat the tips, one can either vapor coat the tip or dip the tips into a dilute solution containing the molecular ink. If one dip-coats the tips, the solvent must be removed prior to deposition. The deposition rate of a molecular ink is dependent on the diffusion rate of the molecule, which is different for each molecule. The size of the feature is controlled by the tip/surface dwell-time (ranging from milliseconds to seconds) and the size of the water meniscus, which is determined by the humidity conditions (assuming the tip's radius of curvature is much smaller than the meniscus).
*Water meniscus mediated (exceptions do exist)
*Nanoscale feature resolution (50 nm to 2000 nm)
*No multiplexed depositions
*Each molecular ink is limited to its corresponding substrate | 2 | Tissue Engineering |
Conceptually, the in vivo bioreactor was borne from complications in a repair method of bone fracture, bone loss, necrosis, and tumor reconstruction known as bone grafting. Traditional bone grafting strategies require fresh, autologous bone harvested from the iliac crest; this harvest site is limited by the amount of bone that can safely be removed, as well as associated pain and morbidity. Other methods include cadaverous allografts and synthetic options (often made of hydroxyapatite) that have become available in recent years. In response to the question of limited bone sourcing, it has been posited that bone can be grown to fit a damaged region within the body through the application of tissue engineering principles.
Tissue engineering is a biomedical engineering discipline that combines biology, chemistry, and engineering to design neotissue (newly formed tissue) on a scaffold. Tissues scaffolds are functionally identical to the extracellular matrix found, acting as a site upon which regenerative cellular components adsorb to encourage cellular growth. This cellular growth is then artificially stimulated by additive growth factors in the environment that encourage tissue formation. The scaffold is often seeded with stem cells and growth additives to encourage a smooth transition from cells to tissues, and more recently, organs. Traditionally, this method of tissue engineering is performed in vitro, where scaffold components and environmental manipulation recreate in vivo stimuli that direct growth. Environmental manipulation includes changes in physical stimulation, pH, potential gradients, cytokine gradients, and oxygen concentration. The overarching goal of in vitro tissue engineering is to create a functional tissue that is equivalent to native tissue in terms of composition, biomechanical properties, and physiological performance. However, in vitro tissue engineering suffers from a limited ability to mimic in vitro conditions, often leading to inadequate tissue substitutes. Therefore, in vivo tissue engineering has been suggested as a method to circumvent the tedium of environmental manipulation and use native in vivo stimuli to direct cell growth. To achieve in vivo tissue growth, an artificial bioreactor space must be established in which cells may grow. The in vivo bioreactor depends on harnessing the reparative qualities of the body to recruit stem cells into an implanted scaffold, and utilize vasculature to supply all necessary growth components. | 2 | Tissue Engineering |
An article published in Nature Materials demonstrated cell efficiencies of 8.2% using a new solvent-free liquid redox electrolyte consisting of a melt of three salts, as an alternative to using organic solvents as an electrolyte solution. Although the efficiency with this electrolyte is less than the 11% being delivered using the existing iodine-based solutions, the team is confident the efficiency can be improved. | 8 | Ultraviolet Radiation |
The central part of a neutron generator is the particle accelerator itself, sometimes called a neutron tube. Neutron tubes have several components including an ion source, ion optic elements, and a beam target; all of these are enclosed within a vacuum-tight enclosure. High voltage insulation between the ion optical elements of the tube is provided by glass and/or ceramic insulators. The neutron tube is, in turn, enclosed in a metal housing, the accelerator head, which is filled with a dielectric medium to insulate the high voltage elements of the tube from the operating area. The accelerator and ion source high voltages are provided by external power supplies. The control console allows the operator to adjust the operating parameters of the neutron tube. The power supplies and control equipment are normally located within of the accelerator head in laboratory instruments, but may be several kilometers away in well logging instruments.
In comparison with their predecessors, sealed neutron tubes do not require vacuum pumps and gas sources for operation. They are therefore more mobile and compact, while also durable and reliable. For example, sealed neutron tubes have replaced radioactive modulated neutron initiators, in supplying a pulse of neutrons to the imploding core of modern nuclear weapons.
Examples of neutron tube ideas date as far back as the 1930s, pre-nuclear weapons era, by German scientists filing a 1938 German patent (March 1938, patent #261,156) and obtaining a United States Patent (July 1941, USP #2,251,190); examples of present state of the art are given by developments such as the Neutristor, a mostly solid state device, resembling a computer chip, invented at Sandia National Laboratories in Albuquerque NM. Typical sealed designs are used in a pulsed mode and can be operated at different output levels, depending on the life from the ion source and loaded targets. | 3 | Nuclear Fusion |
Radium dials are watch, clock and other instrument dials painted with luminous paint containing radium-226 to produce radioluminescence. Radium dials were produced throughout most of the 20th century before being replaced by safer tritium-based luminous material in the 1970s and finally by non-toxic, non-radioactive strontium aluminate–based photoluminescent material from the middle 1990s. | 0 | Luminescence |
Epibiotech developed an autologous dermal papilla cell that was scheduled to enter clinical trials at the end of 2023. | 2 | Tissue Engineering |
A general definition of spherical harmonic super basis of a -multiplet problem can be expressed as
where the parentheses denote a 3-j symbol; K is the rank which ranges ; Q is the
projection index of rank K which ranges from −K to +K. A cubic harmonic super basis where all the tensor operators are hermitian can be defined as
Then, any quantum operator defined in the -multiplet Hilbert space can be expanded as
where the expansion coefficients can be obtained by taking the trace inner product, e.g. .
Apparently, one can make linear combination of these operators to form a new super basis that have different symmetries. | 7 | Magnetic Ordering |
Cell differentiation involves a transition from a proliferative mode toward differentiation mode. Directed differentiation consists in mimicking developmental (embryo's development) decisions in vitro using the stem cells as source material. For this purpose, pluripotent stem cells (PSCs) are cultured in controlled conditions involving specific substrate or extracellular matrices promoting cell adhesion and differentiation, and define culture media compositions. A limited number of signaling factors such as growth factors or small molecules, controlling cell differentiation, is applied sequentially or in a combinatorial manner, at varying dosage and exposure time. Proper differentiation of the cell type of interest is verified by analyzing cell type specific markers, gene expression profile, and functional assays. | 2 | Tissue Engineering |
The latest generation of radioluminescent materials is based on tritium, a radioactive isotope of hydrogen with half-life of 12.32 years that emits very low-energy beta radiation. It is used on wristwatch faces, gun sights, and emergency exit signs. The tritium gas is contained in a small glass tube, coated with a phosphor on the inside. Beta particles emitted by the tritium strike the phosphor coating and cause it to fluoresce, emitting light, usually yellow-green.
Tritium is used because it is believed to pose a negligible threat to human health, in contrast to the previous radioluminescent source, radium, which proved to be a significant radiological hazard. The low-energy 5.7 keV beta particles emitted by tritium cannot pass through the enclosing glass tube. Even if they could, they are not able to penetrate human skin. Tritium is only a health threat if ingested or inhaled. Since tritium is a gas, if a tritium tube breaks, the gas dissipates in the air and is diluted to safe concentrations.
Tritium has a half-life of 12.32 years, so the brightness of a tritium light source will decline to half its initial value in that time. | 0 | Luminescence |
The Landau theory of second-order phase transitions has been applied to magnetic phase transitions. The magnetic space group of disordered structure, , transitions to the magnetic space group of the ordered phase, . is a subgroup of , and keeps only the symmetries which have not been broken during the phase transition. This can be tracked numerically by evolution of the order parameter, which belongs to a single irreducible representation of .
Important magnetic phase transitions include the paramagnetic to ferromagnetic transition at the Curie temperature and the paramagnetic to antiferromagnetic transition at the Néel temperature. Differences in the magnetic phase transitions explain why FeO, MnCO, and CoCO are weakly ferromagnetic, whereas the structurally similar CrO and FeCO are purely antiferromagnetic. This theory developed into what is now known as antisymmetric exchange.
A related scheme is the classification of Aizu species which consist of a prototypical non-ferroic magnetic point group, the letter "F" for ferroic, and a ferromagnetic or ferroelectric point group which is a subgroup of the prototypical group which can be reached by continuous motion of the atoms in the crystal structure. | 7 | Magnetic Ordering |
* Avian myotubes: highly contractile skeletal myotubes cultured and differentiated in vitro on collagen-coated culture plates
* Cultured Meat (CM): cultured, cell based, lab grown, in vitro, clean meat obtained through cellular agriculture
* Human Bio-Artificial Muscle (BAM): formed through a seven day, in vitro tissue engineering procedure in which human myoblasts fuse and differentiate into aligned myofibres in an extracellular matrix; these constructs are used for intramuscular drug injection to replace pre- or non-clinical injection models and complement animal studies
* Myoblast transfer in the treatment of Duchenne's Muscular Dystrophy (DMD): an in vivo technique to replace dystrophin, a skeletal muscle protein which is deficient in patients with DMD; myoblasts fuse with muscle fibers and contribute their nuclei which then replace deficient gene products in the host nuclei
* Autologous hematopoetic stem cell transplantation (AHSCT) as a method for treating Multiple Sclerosis (MS): an in vivo technique for treating MS in which the immune system is destroyed and is reconstituted with hematopoetic stem cells; has been shown to reduce the effects of MS for 4-5 years in 70-80% of patients
* Volumetric muscle loss repair using Muscle Derived Stem Cells (MDSCs): an in situ technique for muscle loss repair in which patients have suffered from trauma or combat injuries; MDSCs cast in an in situ fibrin gel were capable of forming new myofibres that became engrafted in a muscle defect that was created by a partial-thickness wedge resection in the tibialis anterior muscle of laboratory mice
* Development of skeletal muscle organoids to model neuromuscular disorders and muscular dystrophies; an in vitro technique in which human pluripotent stem cells (hPSCs) are differentiated into functional 3D human skeletal muscle organoid (hSkMOs); hPSCs were guided towards the paraxial mesodermal lineage which then gives rise to myogenic pregenitor cells and myoblasts in well plates with no scaffold; organoids were round, uniformly sized, and exhibited homogeneous morphology upon full development and were shown to successfully model muscle development and regeneration
* Bioprinted Tibialis Anterior (TA) Muscle in Rats: an in vitro technique in which bioengineered skeletal muscle tissue composed of human primary muscle pregenitor cells (hMPCs) was fabricated – upon implantation, the bioprinted material reached 82% functional recovery in rodent models of the TA muscle | 2 | Tissue Engineering |
H) tritium (T, hydrogen-3, H) fusion reactions are the most common accelerator based (as opposed to radioactive isotopes) neutron sources. In these systems, neutrons are produced by creating ions of deuterium, tritium, or deuterium and tritium and accelerating these into a hydride target loaded with deuterium, or deuterium and tritium. The DT reaction is used more than the DD reaction because the yield of the DT reaction is 50–100 times higher than that of the DD reaction.
D + T → n + He E = 14.1 MeV
D + D → n + He E = 2.5 MeV
Neutrons produced by DD and DT reactions are emitted somewhat anisotropically from the target, slightly biased in the forward (in the axis of the ion beam) direction. The anisotropy of the neutron emission from DD and DT reactions arises from the fact the reactions are isotropic in the center of momentum coordinate system (COM) but this isotropy is lost in the transformation from the COM coordinate system to the laboratory frame of reference. In both frames of reference, the He nuclei recoil in the opposite direction to the emitted neutron consistent with the law of conservation of momentum.
The gas pressure in the ion source region of the neutron tubes generally ranges between 0.1 and 0.01 mm Hg. The mean free path of electrons must be shorter than the discharge space to achieve ionization (lower limit for pressure) while the pressure must be kept low enough to avoid formation of discharges at the high extraction voltages applied between the electrodes. The pressure in the accelerating region, however, has to be much lower, as the mean free path of electrons must be longer to prevent formation of a discharge between the high voltage electrodes.
The ion accelerator usually consists of several electrodes with cylindrical symmetry, acting as an einzel lens. The ion beam can thus be focused to a small point at the target. The accelerators typically require power supplies of 100–500 kV. They usually have several stages, with voltage between the stages not exceeding 200 kV to prevent field emission.
In comparison with radionuclide neutron sources, neutron tubes can produce much higher neutron fluxes and consistent (monochromatic) neutron energy spectra can be obtained. The neutron production rate can also be controlled. | 3 | Nuclear Fusion |
A sperm bank, semen bank, or cryobank is a facility or enterprise which purchases, stores and sells human semen. The semen is produced and sold by men who are known as sperm donors. The sperm is purchased by or for other persons for the purpose of achieving a pregnancy or pregnancies other than by a sexual partner. Sperm sold by a sperm donor is known as donor sperm.
A sperm bank may be a separate entity supplying donor sperm to individuals or to fertility centers or clinics, or it may be a facility which is run by a clinic or other medical establishment mainly or exclusively for their patients or customers.
A pregnancy may be achieved using donor sperm for insemination with similar outcomes to sexual intercourse. By using sperm from a donor rather than from the sperm recipient's partner, the process is a form of third party reproduction. In the 21st century artificial insemination with donor sperm from a sperm bank is most commonly used for individuals with no male partner, i.e. single women and coupled lesbians.
A sperm donor must generally meet specific requirements regarding age and screening for medical history. In the United States, sperm banks are regulated as Human Cell and Tissue or Cell and Tissue Bank Product (HCT/Ps) establishments by the Food and Drug Administration. Many states also have regulations in addition to those imposed by the FDA. In the European Union a sperm bank must have a license according to the EU Tissue Directive. In the United Kingdom, sperm banks are regulated by the Human Fertilisation and Embryology Authority. | 1 | Cryobiology |
The development of various methods of cryopreservation of bovine embryos improved embryo transfer technique considerably efficient technology, no longer depending on the immediate readiness of suitable recipients. Pregnancy rates are just slightly less than those achieved with fresh embryos. Recently, the use of cryoprotectants such as ethylene glycol has permitted the direct transfer of bovine embryos. The world's first live crossbred bovine calf produced under tropical conditions by Direct Transfer (DT) of embryo frozen in ethylene glycol freeze media was born on 23 June 1996. Dr. Binoy Sebastian Vettical of Kerala Livestock Development Board Ltd has produced the embryo stored frozen in Ethylene Glycol freeze media by slow programmable freezing (SPF) technique and transferred directly to recipient cattle immediately after thawing the frozen straw in water for the birth of this calf. In a study, in vivo produced crossbred bovine embryos stored frozen in ethylene glycol freeze media were transferred directly to recipients under tropical conditions and achieved a pregnancy rate of 50 percent. In a survey of the North American embryo transfer industry, embryo transfer success rates from direct transfer of embryos were as good as to those achieved with glycerol. Moreover, in 2011, more than 95% of frozen-thawed embryos were transferred by Direct Transfer. | 1 | Cryobiology |
In wine tasting, humans are least sensitive to the taste of sweetness (in contrast to sensitivity to bitterness or sourness) with the majority of the population being able to detect sugar or "sweetness" in wines between 1% and 2.5% residual sugar. Additionally, other components of wine such as acidity and tannins can mask the perception of sugar in the wine. | 6 | Carbohydrates |
In DSSC, electrodes consisted of sintered semiconducting nanoparticles, mainly TiO or ZnO. These nanoparticle DSSCs rely on trap-limited diffusion through the semiconductor nanoparticles for the electron transport. This limits the device efficiency since it is a slow transport mechanism. Recombination is more likely to occur at longer wavelengths of radiation. Moreover, sintering of nanoparticles requires a high temperature of about 450 °C, which restricts the fabrication of these cells to robust, rigid solid substrates. It has been proven that there is an increase in the efficiency of DSSC, if the sintered nanoparticle electrode is replaced by a specially designed electrode possessing an exotic nanoplant-like morphology. | 8 | Ultraviolet Radiation |
Hair multiplication or hair cloning is a proposed technique to counter hair loss. The technology to clone hair is in its early stages, but multiple groups have demonstrated pieces of the technology at a small scale with a few in commercial development.
Scientists previously assumed that in the case of complete baldness, follicles are completely absent from the scalp, so they cannot be regenerated. However, it was discovered that the follicles are not entirely absent, as there are stem cells in the bald scalp from which the follicles naturally arise. The abnormal behavior of these follicles is suggested to be the result of progenitor cell deficiency in these areas. One recently discovered molecule (SCUBE3), may aid in activating these cells and regrowing hair.
The basic idea of hair cloning is that healthy follicle cells or dermal papillae can be extracted from the subject from areas that are not bald and are not suffering hair loss. They can be multiplied (cloned) by various culturing methods and the new cells can be injected back into the bald scalp, where they would produce healthy hair. In 2015, initial trials for human hair were successful in generating new follicles, but the hairs grew in various different directions, giving an unnatural look. Scientists believe they may have solved this problem by using nearly microscopic 3D-printed shafts to assist follicles growing upward through the scalp. This technique however is still in the research phase and is not available for public or commercial use.
As of 2023, estimates for when there will be successful hair cloning for humans are around 2030-2035; recent advancements in stem cell research and follicle generation mean that balding may be solved in around 10 years. | 2 | Tissue Engineering |
Superferromagnetism is the magnetism of an ensemble of magnetically interacting super-moment-bearing material particles that would be superparamagnetic if they were not interacting. Nanoparticles of iron oxides, such as ferrihydrite (nominally FeOOH), often cluster and interact magnetically. These interactions change the magnetic behaviours of the nanoparticles (both above and below their blocking temperatures) and lead to an ordered low-temperature phase with non-randomly oriented particle super-moments. | 7 | Magnetic Ordering |
In 1957, it was determined via DNA content that myoblasts proliferate, but myonuclei do not. Following this discovery, the satellite cell was experimentally uncovered by Mauro and Katz as stem cells which sit on the surface of the myofibre and have the capability to differentiate into muscle cells. Satellite cells provide myoblasts for growth, differentiation, and repair of muscle tissue. Muscle tissue engineering officially began as a discipline in 1988 when Herman Vandenburgh cultured avian myotubes in collagen-coated culture plates. Following this development, it was found in 1989 that mechanical stimulation of myoblasts in vitro facilitates engineered skeletal muscle growth. Most of the modern innovations in the field of muscle tissue engineering are found in the 21st century. | 2 | Tissue Engineering |
Such attacks or threats against women who failed to wear hijab, dress "modestly" or otherwise threaten traditional norms have been reported in Afghanistan. In November 2008, extremists subjected girls to acid attacks for attending school. | 4 | Acids + Bases |
Under ideal conditions, implants should initiate the desired host response. Ideally, the implant should not cause any undesired reaction from neighboring or distant tissues. However, the interaction between the implant and the tissue surrounding the implant can lead to complications. The process of implantation of medical devices is subjected to the same complications that other invasive medical procedures can have during or after surgery. Common complications include infection, inflammation, and pain. Other complications that can occur include risk of rejection from implant-induced coagulation and allergic foreign body response. Depending on the type of implant, the complications may vary.
When the site of an implant becomes infected during or after surgery, the surrounding tissue becomes infected by microorganisms. Three main categories of infection can occur after operation. Superficial immediate infections are caused by organisms that commonly grow near or on skin. The infection usually occurs at the surgical opening. Deep immediate infection, the second type, occurs immediately after surgery at the site of the implant. Skin-dwelling and airborne bacteria cause deep immediate infection. These bacteria enter the body by attaching to the implant's surface prior to implantation. Though not common, deep immediate infections can also occur from dormant bacteria from previous infections of the tissue at the implantation site that have been activated from being disturbed during the surgery. The last type, late infection, occurs months to years after the implantation of the implant. Late infections are caused by dormant blood-borne bacteria attached to the implant prior to implantation. The blood-borne bacteria colonize on the implant and eventually get released from it. Depending on the type of material used to make the implant, it may be infused with antibiotics to lower the risk of infections during surgery. However, only certain types of materials can be infused with antibiotics, the use of antibiotic-infused implants runs the risk of rejection by the patient since the patient may develop a sensitivity to the antibiotic, and the antibiotic may not work on the bacteria.
Inflammation, a common occurrence after any surgical procedure, is the body's response to tissue damage as a result of trauma, infection, intrusion of foreign materials, or local cell death, or as a part of an immune response. Inflammation starts with the rapid dilation of local capillaries to supply the local tissue with blood. The inflow of blood causes the tissue to become swollen and may cause cell death. The excess blood, or edema, can activate pain receptors at the tissue. The site of the inflammation becomes warm from local disturbances of fluid flow and the increased cellular activity to repair the tissue or remove debris from the site.
Implant-induced coagulation is similar to the coagulation process done within the body to prevent blood loss from damaged blood vessels. However, the coagulation process is triggered from proteins that become attached to the implant surface and lose their shapes. When this occurs, the protein changes conformation and different activation sites become exposed, which may trigger an immune system response where the body attempts to attack the implant to remove the foreign material. The trigger of the immune system response can be accompanied by inflammation. The immune system response may lead to chronic inflammation where the implant is rejected and has to be removed from the body. The immune system may encapsulate the implant as an attempt to remove the foreign material from the site of the tissue by encapsulating the implant in fibrinogen and platelets. The encapsulation of the implant can lead to further complications, since the thick layers of fibrous encapsulation may prevent the implant from performing the desired functions. Bacteria may attack the fibrous encapsulation and become embedded into the fibers. Since the layers of fibers are thick, antibiotics may not be able to reach the bacteria and the bacteria may grow and infect the surrounding tissue. In order to remove the bacteria, the implant would have to be removed. Lastly, the immune system may accept the presence of the implant and repair and remodel the surrounding tissue. Similar responses occur when the body initiates an allergic foreign body response. In the case of an allergic foreign body response, the implant would have to be removed. | 2 | Tissue Engineering |
Larger scale reverse osmosis water purification units (ROWPU) exist for military use. These have been adopted by the United States armed forces and the Canadian Forces. Some models are containerized, some are trailers, and some are themselves vehicles.
The water is treated with a polymer to initiate coagulation. Next, it is run through a multi-media filter where it undergoes primary treatment, removing turbidity. It is then pumped through a cartridge filter which is usually spiral-wound cotton. This process strips any particles larger than 5 µm and eliminates almost all turbidity.
The clarified water is then fed through a high-pressure piston pump into a series of RO vessels. 90.00–99.98% of the raw water's total dissolved solids are removed and military standards require that the result have no more than 1000–1500 parts per million by measure of electrical conductivity. It is then disinfected with chlorine. | 5 | Separation Processes |
The first tagged stamps of Canada were issued in 1962 with vertical phosphorescent bands. In 1972, fluorescent general tagging was introduced, initially as vertical bars, now normally on all four sides of the stamp. | 0 | Luminescence |
Various chemical and genetic strategies have been developed to manipulate O-GlcNAc, both on a proteome-wide basis and on specific proteins. | 6 | Carbohydrates |
Most solid state acids are organic acids such as oxalic acid, tartaric acid, citric acid, maleic acid, etc. Examples of inorganic solid acids include silico-aluminates (zeolites, alumina, silico-aluminophosphate), and sulfated zirconia. Many transition metal oxides are acidic, including titania, zirconia, and niobia. Such acids are used in cracking. Many solid Brønsted acids are also employed industrially, including polystyrene sulfonate, solid phosphoric acid, niobic acid, and heteropolyoxometallates. | 4 | Acids + Bases |
The microscope setup is based on an inverted microscope design. An automated stage is used to record larger areas by mosaicing a series of single adjacent frames. The LED light is focused using a ball lens with a short focal length onto the sample surface in an oblique-angle cis-illumination scheme since standard microscopy optics do not transmit UV light efficiently. No dichroic mirror or filter is required as microscope objectives are opaque to UV excitation light. The emitted fluorescence light is collected using a long-working-distance objective and focused via a tube lens onto a CCD camera.
Specimens are submerged in exogenous dye for 10 seconds and then briefly washed in water or phosphate-buffered saline (PBS). The resulting stained specimens generate bright enough signals for direct and interpretable visualization through microscope eyepiece. | 8 | Ultraviolet Radiation |
Glycan arrays, like that offered by the Consortium for Functional Glycomics (CFG), National Center for Functional Glycomics (NCFG) and [http://www.zbiotech.com/ Z Biotech, LLC], contain carbohydrate compounds that can be screened with lectins, antibodies or cell receptors to define carbohydrate specificity and identify ligands. Glycan array screening works in much the same way as other microarray that is used for instance to study gene expression DNA microarrays or protein interaction Protein microarrays.
Glycan arrays are composed of various oligosaccharides and/or polysaccharides immobilised on a solid support in a spatially-defined arrangement. This technology provides the means of studying glycan-protein interactions in a high-throughput environment. These natural or synthetic (see carbohydrate synthesis) glycans are then incubated with any glycan-binding protein such as lectins, cell surface receptors or possibly a whole organism such as a virus. Binding is quantified using fluorescence-based detection methods. Certain types of glycan microarrays can even be re-used for multiple samples using a method called Microwave Assisted Wet-Erase. | 6 | Carbohydrates |
The NIF burning plasma, despite not occurring in an energy context, has been characterised as a major milestone in the race towards nuclear fusion power, with the perception that it could bring with it a better planet. The first controlled burning plasma has been characterized as a critical juncture on the same level as the Trinity Test, with enormous implications for fusion for energy (fusion power), including the weaponization of fusion power, mainly for electricity for directed-energy weapons, as well as fusion for peacebuilding – one of the main tasks of ITER. | 3 | Nuclear Fusion |
Indoor tanning is most popular with white females, 16–25 years old, with low-to-moderate skin sensitivity, who know other tanners. Studies seeking to link indoor tanning to education level and income have returned inconsistent results. Prevalence was highest in one German study among those with a moderate level of education (neither high nor low).
The late teens to early–mid 20s is the highest-prevalence age group. In a national survey of white teenagers in 2003 in the US (aged 13–19), 24% had used a tanning facility. Indoor-tanning prevalence figures in the US vary from 30 million each year to just under 10 million (7.8 million women and 1.9 million men).
The figures in the US are in decline: according to the Centres for Disease Control and Prevention, usage in the 18–29 age group fell from 11.3 percent in 2010 to 8.6 percent in 2013, perhaps attributable in part to a 10% "tanning tax" introduced in 2010. Attitudes toward tanning vary across states; in one study, doctors in the northeast and midwest of the country were more likely than those in the south or west to recommend tanning beds to treat vitamin D deficiency and depression.
Tanning bed use is more prevalent in northern countries. In Sweden in 2001, 44% said they had used one (in a survey of 1,752 men and women aged 18–37). Their use increased in Denmark between 1994 and 2002 from 35% to 50% (reported use in the previous two years). In Germany, between 29% and 47% had used one, and one survey found that 21% had done so in the previous year. In France, 15% of adults in 1994–1995 had tanned indoors; the practice was more common in the north of France. In 2006, 12% of grade 9–10 students in Canada had used a tanning bed in the last year. In 2004, 7% of 8–11-year-olds in Scotland said they had used one. Tanning bed use is higher in the UK in the north of England. One study found that the prevalence was lower in London than in less urban areas of the country. | 8 | Ultraviolet Radiation |
PUVA (psoralen and UVA) is an ultraviolet light therapy treatment for skin diseases: vitiligo, eczema, psoriasis, graft-versus-host disease, mycosis fungoides, large plaque parapsoriasis, and cutaneous T-cell lymphoma, using the sensitizing effects of the drug psoralen. The psoralen is applied or taken orally to sensitize the skin, then the skin is exposed to UVA.
Photodynamic therapy is the general use of nontoxic light-sensitive compounds that are exposed selectively to light, whereupon they become toxic to targeted malignant and other diseased cells. Still, PUVA therapy is often classified as a separate technique from photodynamic therapy. | 8 | Ultraviolet Radiation |
MUSE system mainly serves as a low-cost alternative to traditional histological analysis for cancer diagnostics with simpler and less time-consuming techniques. By integrating microscopy and fresh tissue fluorescence staining into an automated optical system, the overall acquiring time needed for getting digital images with diagnostic values can be much shortened into the scale of minutes comparing with conventional pathology, where general procedure can take from hours to days. The color-mapping techniques that correlated fluorescence staining to traditional H&E staining provide the same visual representation to pathologists based on existing knowledge with no need for additional training on image recognition.
Additionally, this system also has great potential to be used for intraoperative consultation, a method performed in pathologists lab that examine the microscopic features of tissue during oncological surgery usually for rapid cancer lesion and margin detection. It also can play an important role in biological and medical research, which might require examination on cellular features of tissue samples. In the future, the system can be further optimized to include more features including staining protocol, LEDs wavelength for more research usages and applications. | 8 | Ultraviolet Radiation |
The property by which some neurons do not return to their basal conditions from a stimulated condition immediately after removal of the stimulus is an example of hysteresis. | 7 | Magnetic Ordering |
Di(2-ethylhexyl)phosphoric acid (DEHPA or HDEHP) is an organophosphorus compound with the formula (CHO)POH. The colorless liquid is a diester of phosphoric acid and 2-ethylhexanol. It is used in the solvent extraction of uranium, vanadium and the rare-earth metals. | 5 | Separation Processes |
In larger urban centres, studies have noted that lesbian, gay, bisexual, transgender and queer (LGBTQ+) populations are among the fastest-growing users of fertility care. IVF is increasingly being used to allow lesbian and other LGBT couples to share in the reproductive process through a technique called reciprocal IVF. The eggs of one partner are used to create embryos which the other partner carries through pregnancy. For gay male couples, many elect to use IVF through gestational surrogacy, where one partners sperm is used to fertilise a donor ovum, and the resulting embryo is transplanted into a surrogate carriers womb. There are various IVF options available for same-sex couples including, but not limited to, IVF with donor sperm, IVF with a partners oocytes, reciprocal IVF, IVF with donor eggs, and IVF with gestational surrogate. IVF with donor sperm can be considered traditional IVF for lesbian couples, but reciprocal IVF or using a partners oocytes are other options for lesbian couples trying to conceive to include both partners in the biological process. Using a partners oocytes is an option for partners who are unsuccessful in conceiving with their own, and reciprocal IVF involves undergoing reproduction with a donor egg and sperm that is then transferred to a partner who will gestate. Donor IVF involves conceiving with a third partys eggs. Typically, for gay male couples hoping to use IVF, the common techniques are using IVF with donor eggs and gestational surrogates. | 1 | Cryobiology |
* Stilbene is used in manufacture of dyes and optical brighteners, and also as a phosphor and a scintillator.
* Stilbene is one of the gain mediums used in dye lasers. | 0 | Luminescence |
The enthalpy of sublimation has commonly been predicted using the equipartition theorem. If the lattice energy is assumed to be approximately half the packing energy, then the following thermodynamic corrections can be applied to predict the enthalpy of sublimation. Assuming a 1 molar ideal gas gives a correction for the thermodynamic environment (pressure and volume) in which pV = RT, hence a correction of 1RT. Additional corrections for the vibrations, rotations and translation then need to be applied. From the equipartition theorem gaseous rotation and translation contribute 1.5RT each to the final state, therefore a +3RT correction. Crystalline vibrations and rotations contribute 3RT each to the initial state, hence −6RT. Summing the RT corrections; −6RT + 3RT + RT = −2RT. This leads to the following approximate sublimation enthalpy. A similar approximation can be found for the entropy term if rigid bodies are assumed. | 5 | Separation Processes |
The major disadvantage to the DSSC design is the use of the liquid electrolyte, which has temperature stability problems. At low temperatures the electrolyte can freeze, halting power production and potentially leading to physical damage. Higher temperatures cause the liquid to expand, making sealing the panels a serious problem. Another disadvantage is that costly ruthenium (dye), platinum (catalyst) and conducting glass or plastic (contact) are needed to produce a DSSC. A third major drawback is that the electrolyte solution contains volatile organic compounds (or VOC's), solvents which must be carefully sealed as they are hazardous to human health and the environment. This, along with the fact that the solvents permeate plastics, has precluded large-scale outdoor application and integration into flexible structure.
Replacing the liquid electrolyte with a solid has been a major ongoing field of research. Recent experiments using solidified melted salts have shown some promise, but currently suffer from higher degradation during continued operation, and are not flexible. | 8 | Ultraviolet Radiation |
The basic room purge equation can be used only for purge scenarios. In a scenario where a liquid continuously evaporates from a container in a ventilated room, a differential equation has to be used:
where the ventilation rate has been adjusted by a mixing factor K:
*C = concentration of a gas
*G = generation rate
*V = room volume
*Q′ = adjusted ventilation rate of the volume | 5 | Separation Processes |
With further increases of temperature and density, fusion processes produce nuclides only up to nickel-56 (which decays later to iron); heavier elements (those beyond Ni) are created mainly by neutron capture. The slow capture of neutrons, the s-process, produces about half of elements beyond iron. The other half are produced by rapid neutron capture, the r-process, which probably occurs in core-collapse supernovae and neutron star mergers. | 3 | Nuclear Fusion |
Rewarming can be done with a number of methods including passive external rewarming, active external rewarming, and active internal rewarming. Passive external rewarming involves the use of a person's own ability to generate heat by providing properly insulated dry clothing and moving to a warm environment. Passive external rewarming is recommended for those with mild hypothermia.
Active external rewarming involves applying warming devices externally, such as a heating blanket. These may function by warmed forced air (Bair Hugger is a commonly used device), chemical reactions, or electricity. In wilderness environments, hypothermia may be helped by placing hot water bottles in both armpits and in the groin. Active external rewarming is recommended for moderate hypothermia. Active core rewarming involves the use of intravenous warmed fluids, irrigation of body cavities with warmed fluids (the chest or abdomen), use of warm humidified inhaled air, or use of extracorporeal rewarming such as via a heart lung machine or extracorporeal membrane oxygenation (ECMO). Extracorporeal rewarming is the fastest method for those with severe hypothermia. When severe hypothermia has led to cardiac arrest, effective extracorporeal warming results in survival with normal mental function about 50% of the time. Chest irrigation is recommended if bypass or ECMO is not possible.
Rewarming shock (or rewarming collapse) is a sudden drop in blood pressure in combination with a low cardiac output which may occur during active treatment of a severely hypothermic person. There was a theoretical concern that external rewarming rather than internal rewarming may increase the risk. These concerns were partly believed to be due to afterdrop, a situation detected during laboratory experiments where there is a continued decrease in core temperature after rewarming has been started. Recent studies have not supported these concerns, and problems are not found with active external rewarming. | 1 | Cryobiology |
An endotransglucosylase is an enzyme which is able to transfer a saccharide unit from one saccharide to another. | 6 | Carbohydrates |
Oleum is an important intermediate in the manufacture of sulfuric acid due to its high enthalpy of hydration. When SO is added to water, rather than dissolving, it tends to form a fine mist of sulfuric acid, which is difficult to manage. However, SO added to concentrated sulfuric acid readily dissolves, forming oleum which can then be diluted with water to produce additional concentrated sulfuric acid.
Typically, above concentrations of 98.3%, sulfuric acid will undergo a spontaneous decomposition into sulfur trioxide and water
This means that sulfuric acid above said concentration will readily degenerate until it reaches 98.3%; this is impractical in some applications such as synthesis where anhydrous conditions are preferred (like alcohol eliminations). The addition of sulfur trioxide allows the concentration to be increased by means of Le Chatelier's principle. | 4 | Acids + Bases |
A weak acid is a substance that partially dissociates when it is dissolved in a solvent. In solution there is an equilibrium between the acid, , and the products of dissociation.
The solvent (e.g. water) is omitted from this expression when its concentration is effectively unchanged by the process of acid dissociation. The strength of a weak acid can be quantified in terms of a dissociation constant, , defined as follows, where signifies the concentration of a chemical moiety, X.
When a numerical value of is known it can be used to determine the extent of dissociation in a solution with a given concentration of the acid, , by applying the law of conservation of mass.
where is the value of the analytical concentration of the acid. When all the quantities in this equation are treated as numbers, ionic charges are not shown and this becomes a quadratic equation in the value of the hydrogen ion concentration value, .
This equation shows that the pH of a solution of a weak acid depends on both its value and its concentration. Typical examples of weak acids include acetic acid and phosphorous acid. An acid such as oxalic acid () is said to be dibasic because it can lose two protons and react with two molecules of a simple base. Phosphoric acid () is tribasic.
For a more rigorous treatment of acid strength see acid dissociation constant. This includes acids such as the dibasic acid succinic acid, for which the simple method of calculating the pH of a solution, shown above, cannot be used. | 4 | Acids + Bases |
Cryoprotectants are also used to preserve foods. These compounds are typically sugars that are inexpensive and do not pose any toxicity concerns. For example, many (raw) frozen chicken products contain a sucrose and sodium phosphates solution in water. | 1 | Cryobiology |
Mass spectrometry identified S-GlcNAc as a post-translational modification found on cysteine residues. In vitro experiments demonstrated that OGT could catalyze the formation of S-GlcNAc and that OGA is incapable of hydrolyzing S-GlcNAc. Though a previous report suggested that OGA is capable of hydrolyzing thioglycosides, this was only demonstrated on the aryl thioglycoside para-nitrophenol-S-GlcNAc; para-nitrothiophenol is a more activated leaving group than a cysteine residue. Recent studies have supported the use of S-GlcNAc as an enzymatically stable structural model of O-GlcNAc that can be incorporated through solid-phase peptide synthesis or site-directed mutagenesis. | 6 | Carbohydrates |
The phenomenon appears to have been first described and the term "superferromagnatism" introduced by Bostanjoglo and Röhkel, for a metallic film system. A decade later, the same phenomenon was rediscovered and described to occur in small-particle systems. The discovery is attributed as such in the scientific literature. | 7 | Magnetic Ordering |
OFM was developed and is manufactured by Aroa Biosurgery Limited (New Zealand, formerly Mesynthes Limited, New Zealand) and was first patented in 2008 and described in the scientific literature in 2010. OFM is manufactured from sheep rumen tissue, using a process of decellularization to selectively remove the unwanted sheep cells and cell components to leave an intact and functional extracellular matrix. OFM comprises a special layer of tissue found in rumen, the propria submucosa, which is structurally and functionally distinct from the submucosa of other gastrointestinal tissues.
OFM was first cleared by the FDA in 2009 for the treatment of wounds. Since 2008 there have been >70 publications describing OFM and its clinical applications, and over 6 million clinical applications of OFM-based devices. | 2 | Tissue Engineering |
The spin ice model is only one subdivision of frustrated systems. The word frustration was initially introduced to describe a systems inability to simultaneously minimize the competing interaction energy between its components. In general frustration is caused either by competing interactions due to site disorder (see also the Villain model') or by lattice structure such as in the triangular, face-centered cubic (fcc), hexagonal-close-packed, tetrahedron, pyrochlore and kagome lattices with antiferromagnetic interaction. So frustration is divided into two categories: the first corresponds to the spin glass, which has both disorder in structure and frustration in spin; the second is the geometrical frustration with an ordered lattice structure and frustration of spin. The frustration of a spin glass is understood within the framework of the RKKY model, in which the interaction property, either ferromagnetic or anti-ferromagnetic, is dependent on the distance of the two magnetic ions. Due to the lattice disorder in the spin glass, one spin of interest and its nearest neighbors could be at different distances and have a different interaction property, which thus leads to different preferred alignment of the spin. | 7 | Magnetic Ordering |
Commercial tanning services are banned in all states, except the Northern Territory where no salons are in operation. Private ownership of tanning beds is permitted. | 8 | Ultraviolet Radiation |
Stilbene exists as two possible isomers known as (E)-stilbene and (Z)-stilbene. (Z)-Stilbene is sterically hindered and less stable because the steric interactions force the aromatic rings 43° out-of-plane and prevent conjugation. (Z)-Stilbene has a melting point of , while (E)-stilbene melts around , illustrating that the two compounds are quite different. | 0 | Luminescence |
This effect was first seen by Russian physicists in the 1960s in A.F.Ioffe Physicotechnical Institute, Leningrad, Russia. Subsequently, it was studied in semiconductors such as indium antimonide (InSb), germanium (Ge) and indium arsenide (InAs) by workers in West Germany, Ukraine (Institute of Semiconductor Physics, Kyiv), Japan (Chiba University) and the United States. It was first observed in the mid-infrared (3-5 µm wavelength) in the more convenient diode structures in InSb heterostructure diodes by workers at the Defence Research Agency, Great Malvern, UK (now QinetiQ). These British workers later demonstrated LWIR band (8-12 µm) negative luminescence using mercury cadmium telluride diodes.
Later the Naval Research Laboratory, Washington DC, started work on negative luminescence in mercury cadmium telluride (HgCdTe). The phenomenon has since been observed by several university groups around the world. | 0 | Luminescence |
Hybrid nuclear fusion–fission (hybrid nuclear power) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes.
The basic idea is to use high-energy fast neutrons from a fusion reactor to trigger fission in non-fissile fuels like U-238 or Th-232. Each neutron can trigger several fission events, multiplying the energy released by each fusion reaction hundreds of times. As the fission fuel is not fissile, there is no self-sustaining chain reaction from fission. This would not only make fusion designs more economical in power terms, but also be able to burn fuels that were not suitable for use in conventional fission plants, even their nuclear waste.
In general terms, the hybrid is similar in concept to the fast breeder reactor, which uses a compact high-energy fission core in place of the hybrid's fusion core. Another similar concept is the accelerator-driven subcritical reactor, which uses a particle accelerator to provide the neutrons instead of nuclear reactions. | 3 | Nuclear Fusion |
Only recently also other extraction applications have been investigated, e.g. the large scale recovery of apolar organics on offshore oil platforms using the so-called Macro-Porous Polymer Extraction (MPPE) Technology. In such an application, where the SIR particles are contained in a packed bed, flow rates from 0.5 m h upward without maximum flow restrictions can apparently be treated cost competitive to air stripping/activated carbon, steam stripping and bio treatment systems, according to the technology developer. Additional investigations, mostly done in an academic environment, include polar organics like amino-alcohols, organic acids, amino acids, flavonoids, and aldehydes on a bench-scale or pilot-scale. Also, the application of SIRs for the separation of more polar solutes, such as for instance ethers and phenols, has been investigated in the group of A.B. de Haan. | 5 | Separation Processes |
This method consists in exposing the cells to specific signaling pathways modulators and manipulating cell culture conditions (environmental or exogenous) to mimick the natural sequence of developmental decisions to produce a given cell type/tissue. A drawback of this approach is the necessity to have a good understanding of how the
cell type of interest is formed. | 2 | Tissue Engineering |
In New Zealand, indoor tanning is regulated by a voluntary code of practice. Salons are asked to turn away under-18s, those with type 1 skin (fair skin that burns easily or never tans), people who experienced episodes of sunburn as children, and anyone taking certain medications, with several moles, or who has had skin cancer. Tanners are asked to sign a consent form, which includes health information and advice about the importance of wearing goggles. Surveys have found a high level of non-compliance. The government has carried out bi-annual surveys of tanning facilities since 2012. | 8 | Ultraviolet Radiation |
Winnowing is a process by which chaff is separated from grain. It can also be used to remove pests from stored grain. Winnowing usually follows threshing in grain preparation. In its simplest form, it involves throwing the mixture into the air so that the wind blows away the lighter chaff, while the heavier grains fall back down for recovery. Techniques included using a winnowing fan (a shaped basket shaken to raise the chaff) or using a tool (a winnowing fork or shovel) on a pile of harvested grain. | 5 | Separation Processes |
Galactan (galactosan) is a polysaccharide consisting of polymerized galactose. In general, galactans in natural sources contain a core of galactose units connected by α(1→3) or α(1→6), with structures containing other monosaccharides as side-chains.
Galactan derived from Anogeissus latifolia is primarily α(1→6), but galactan from acacia trees is primarily α(1→3).
Halymenia durvillei is a red seaweed (algae) that produces a sulfated galactan. Several other algae species also contain galactans. Including Carpopeltis . | 6 | Carbohydrates |
Organoid formation generally requires culturing the stem cells or progenitor cells in a 3D medium. Stem cells have the ability to self-renew and differentiate into various cell subtypes, and they enable understanding the processes of development and disease progression. Therefore organoids derived from stem cells enable studying biology and physiology at the organ level. The 3D medium can be made using an extracellular matrix hydrogel such as Matrigel or Cultrex BME, which is a laminin-rich extracellular matrix that is secreted by the Engelbreth-Holm-Swarm tumor line. Organoid bodies can then be made through embedding stem cells in the 3D medium. When pluripotent stem cells are used for the creation of the organoid, the cells are usually, but not all the time, allowed to form embryoid bodies. Those embryoid bodies are then pharmacologically treated with patterning factors to drive the formation of the desired organoid identity. Organoids have also been created using adult stem cells extracted from the target organ, and cultured in 3D media.
Biochemical cues have been incorporated in 3D organoid cultures and with exposure of morphogenes, morphogen inhibitors, or growth factors, organoid models can be developed using embryonic stem cells (ESCs) or adult stem cells (ASCs). Vascularization techniques can be utilized to embody microenvironments that are close to their counterparts, physiologically. Vasculature systems that can facilitate oxygen or nutrients to the inner mass of organoids can be achieved through microfluidic systems, vascular endothelial growth factor delivery systems, and endothelial cell-coated modules. With patient-derived induced pluripotent stem cells (iPSCs) and CRISPR/Cas-based genome editing technologies, genome-edited or mutated pluripotent stem cells (PSCs) with altered signaling cues can be generated to control intrinsic cues within organoids. | 2 | Tissue Engineering |
Accurate determination of core temperature often requires a special low temperature thermometer, as most clinical thermometers do not measure accurately below . A low temperature thermometer can be placed in the rectum, esophagus or bladder. Esophageal measurements are the most accurate and are recommended once a person is intubated. Other methods of measurement such as in the mouth, under the arm, or using an infrared ear thermometer are often not accurate.
As a hypothermic person's heart rate may be very slow, prolonged feeling for a pulse could be required before detecting. In 2005, the American Heart Association recommended at least 30–45 seconds to verify the absence of a pulse before initiating CPR. Others recommend a 60-second check.
The classical ECG finding of hypothermia is the Osborn J wave. Also, ventricular fibrillation frequently occurs below and asystole below . The Osborn J may look very similar to those of an acute ST elevation myocardial infarction. Thrombolysis as a reaction to the presence of Osborn J waves is not indicated, as it would only worsen the underlying coagulopathy caused by hypothermia. | 1 | Cryobiology |
The human gut-on-a-chip contains two microchannels that are separated by the flexible porous Extracellular Matrix (ECM)-coated membrane lined by the gut epithelial cells: Caco-2, which has been used extensively as the intestinal barrier. Caco-2 cells are cultured under spontaneous differentiation of its parental cell, a human colon adenocarcinoma, that represent the model of protective and absorptive properties of the gut. The microchannels are fabricated from polydimethylsiloxane (PDMS) polymer. In order to mimic the gut microenvironment, peristalsis-like fluid flow is designed. By inducing suction in the vacuum chambers along both sides of the main cell channel bilayer, cyclic mechanical strain of stretching and relaxing are developed to mimic the gut behaviors. Furthermore, cells undergo spontaneous villus morphogenesis and differentiation, which generalizes characteristics of intestinal cells. Under the three-dimensional villi scaffold, cells not only proliferate, but metabolic activities are also enhanced. Another important player in the gut is the microbes, namely gut microbiota. Many microbial species in the gut microbiota are strict anaerobes. In order to co-culture these oxygen intolerant anaerobes with the oxygen favorable intestinal cells, a polysulfone fabricated gut-on-a-chip is designed. The system maintained the co-culture of colon epithelial cells, goblet-like cells, and bacteria Faecalibacterium prausnitzii, [https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=39491 Eubacterium rectale], and Bacteroides thetaiotaomicron.
Oral administration is one of the most common methods for drug administration. It allows patients, especially out-patients, to self-serve the drugs with minimal possibility of experiencing acute drug reactions and in most cases: pain-free. However, the drug's action in the body can be largely influenced by the first pass effect. The gut, which plays an important role in the human digestive system, determines the effectiveness of a drug by absorbing its chemical and biological properties selectively. While it is costly and time consuming to develop new drugs, the fact that the gut-on-a-chip technology attains a high level of throughput has significantly decreased research and development costs and time for new drugs.
Even though the cause for inflammatory bowel disease (IBD) is elusive, its pathophysiology involves the gut microbiota. Current methods of inducing IBD are using inflammatory cues to activate Caco-2. It was found that the intestinal epithelium experienced a reduction in barrier function and increased cytokine concentrations. The gut-on-a-chip allowed for the assessment on drug transport, absorption and toxicity as well as potential developments in studying pathogenesis and interactions in the microenvironment overall. Immune cells are essential in mediating inflammatory processes in many gastrointestinal disorders, a recent gut-on-a-chip system also includes multiple immune cells, e.g., macrophages, dendritic cells, and CD4+ T cells in the system. Additionally, the gut-on-a-chip allows the testing of anti-inflammatory effects of bacterial species.
The chip was used to model human radiation-induced injury to the intestine in vitro as it recapitulated the injuries at both cellular and tissue levels. Injuries include but not limited to: inhabitation of mucus production, promotion of villus blunting, and distortion of microvilli. | 2 | Tissue Engineering |
Drug cartels such as the Los Zetas are known to use acid on civilians. For example, In the 2011 San Fernando massacre, Los Zetas members took away children from their mothers, and shot the rest of the civilians in a bus. The women were taken to a warehouse where many other women were held captive. Inside a dark room, the women were reportedly raped and beaten. Screams of the women and of the children being put in acid were also heard. | 4 | Acids + Bases |
A solar-powered desalination unit produces potable water from saline water by using a photovoltaic system to supply the energy. Solar power works well for water purification in settings lacking grid electricity and can reduce operating costs and greenhouse emissions. For example, a solar-powered desalination unit designed passed tests in Australia's Northern Territory.
Sunlight's intermittent nature makes output prediction difficult without an energy storage capability. However batteries or thermal energy storage systems can provide power when the sun does not. | 5 | Separation Processes |
Natural-synthetic hybrid polymers are based on the synergic effect between synthetic and biopolymeric constituents. Gelatin-methacryloyl (GelMA) has become a popular biomaterial in the field of bioprinting. GelMA has shown it has viable potential as a bioink material due to its suitable biocompatibility and readily tunable psychochemical properties. Hyaluronic acid (HA)-PEG is another natural-synthetic hybrid polymer that has proven to be very successful in bioprinting applications. HA combined with synthetic polymers aid in obtaining more stable structures with high cell viability and limited loss in mechanical properties after printing. A recent application of HA-PEG in bioprinting is the creation of artificial liver. Lastly, a series of biodegradable polyurethane (PU)-gelatin hybrid polymers with tunable mechanical properties and efficient degradation rates have been implemented in organ printing. This hybrid has the ability to print complicated structures such as a nose-shaped construct.
All of the polymers described above have the potential to be manufactured into implantable, bioartificial organs for purposes including, but not limited to, customized organ restoration, drug screening, as well as metabolic model analysis. | 2 | Tissue Engineering |
Glow sticks are used for outdoor recreation, often used at night for marking. Scuba divers use diving-rated glow sticks to mark themselves during night dives, and then can turn off bright diving lights. This is done to enable visibility of bioluminescent marine organisms, which cannot be seen while a bright dive light is illuminated. Glow sticks are used on backpacks, tent pegs, and on jackets during overnight camping expeditions. Often, glow sticks are recommended as an addition to survival kits. | 0 | Luminescence |
* Intracoronary Administration of Bone Marrow-Derived Progenitor Cells: an in vivo technique in which progenitor cells derived from bone marrow are administered into an infarct artery to differentiate into functional cardiac cells and recover contractile function after an acute, ST-elevation myocardial infarction, thus preventing adverse remodeling of the left ventricle.
* Human Cardiac Organoids:an in vitro, scaffold-free technique for producing a functioning cardiac organoid; cardiac spheroids made from a mixed cell population derived from human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) cultured on gelatin-coated well plates, without a scaffold, resulted in the generation of a functioning cardiac organoid | 2 | Tissue Engineering |
The equilibrium shapes of bubbles expanding and contracting on capillaries (blunt needles) can exhibit hysteresis depending on the relative magnitude of the maximum capillary pressure to ambient pressure, and the relative magnitude of the bubble volume at the maximum capillary pressure to the dead volume in the system. The bubble shape hysteresis is a consequence of gas compressibility, which causes the bubbles to behave differently across expansion and contraction. During expansion, bubbles undergo large non equilibrium jumps in volume, while during contraction the bubbles are more stable and undergo a relatively smaller jump in volume resulting in an asymmetry across expansion and contraction. The bubble shape hysteresis is qualitatively similar to the adsorption hysteresis, and as in the contact angle hysteresis, the interfacial properties play an important role in bubble shape hysteresis.
The existence of the bubble shape hysteresis has important consequences in interfacial rheology experiments involving bubbles. As a result of the hysteresis, not all sizes of the bubbles can be formed on a capillary. Further the gas compressibility causing the hysteresis leads to unintended complications in the phase relation between the applied changes in interfacial area to the expected interfacial stresses. These difficulties can be avoided by designing experimental systems to avoid the bubble shape hysteresis. | 7 | Magnetic Ordering |
3D cell-culture models exceed 2D culture systems by promoting higher levels of cell differentiation and tissue organization. 3D culture systems are more successful because the flexibility of the ECM gels accommodates shape changes and cell-cell connections – formerly prohibited by rigid 2D culture substrates. Nevertheless, even the best 3D culture models fail to mimic an organs cellular properties in many aspects, including tissue-to-tissue interfaces (e.g., epithelium and vascular endothelium), spatiotemporal gradients of chemicals, and the mechanically active microenvironments (e.g. arteries vasoconstriction and vasodilator responses to temperature differentials). The application of microfluidics in organs-on-chips enables the efficient transport and distribution of nutrients and other soluble cues throughout the viable 3D tissue constructs. Organs-on-chips are referred to as the next wave of 3D cell-culture models that mimic whole living organs' biological activities, dynamic mechanical properties and biochemical functionalities. | 2 | Tissue Engineering |
As a scientist with the American Red Cross, Fahy was the originator of the first practical method of cryopreservation by vitrification and the inventor of computer-based systems to apply this technology to whole organs. Before joining Twenty-First Century Medicine, he was the chief scientist for Organ, Inc and of LRT, Inc. He was also Head of the Tissue Cryopreservation Section of the Transfusion and Cryopreservation Research Program of the U.S. Naval Medical Research Institute in Bethesda, Maryland where he spearheaded the original concept of ice blocking agents. In 2014, he was named a Fellow of the Society for Cryobiology in recognition of the impact of his work in low temperature biology.
In 2015–2017, Fahy led the TRIIM (Thymus Regeneration, Immunorestoration, and Insulin Mitigation) human clinical trial, designed to reverse aspects of human aging. The purpose of the TRIIM trial was to investigate the possibility of using recombinant human growth hormone (rhGH) to prevent or reverse signs of immunosenescence in ten 51‐ to 65‐year‐old putatively healthy men. The study: | 1 | Cryobiology |
Neutron generators find application in semiconductor production industry. They also have use cases in the enrichment of depleted uranium, acceleration of breeder reactors, and activation and excitement of experimental thorium reactors.
In material analysis neutron activation analysis is used to determine concentration of different elements in mixed materials such as minerals or ores. | 3 | Nuclear Fusion |
Managing populations based on minimizing mean kinship values is often an effective way to increase genetic diversity and to avoid inbreeding within captive populations. Kinship is the probability that two alleles will be identical by descent when one allele is taken randomly from each mating individual. The mean kinship value is the average kinship value between a given individual and every other member of the population. Mean kinship values can help determine which individuals should be mated. In choosing individuals for breeding, it is important to choose individuals with the lowest mean kinship values because these individuals are least related to the rest of the population and have the least common alleles. This ensures that rarer alleles are passed on, which helps to increase genetic diversity. It is also important to avoid mating two individuals with very different mean kinship values because such pairings propagate both the rare alleles that are present in the individual with the low mean kinship value as well as the common alleles that are present in the individual with the high mean kinship value. This genetic management technique requires that ancestry is known, so in circumstances where ancestry is unknown, it might be necessary to use molecular genetics such as microsatellite data to help resolve unknowns. | 1 | Cryobiology |
The Venetian blind design is a type of electrostatic direct collector. The Venetian Blind design name comes from the visual similarity of the ribbons to venetian window blinds. Designs in the early 1970s by William Barr and Ralph Moir used repeating metal ribbons at a specified angle as the ion collector plates. These metal ribbon-like surfaces are more transparent to ions going forward than to ions going backward. Ions pass through surfaces of successively increasing potential until they turn and start back, along a parabolic trajectory. They then see opaque surfaces and are caught. Thus ions are sorted by energy with high-energy ions being caught on high-potential electrodes.
William Barr and Ralph Moir then ran a group which did a series of direct energy conversion experiments through the late 1970s and early 1980s. The first experiments used beams of positives and negatives as fuel, and demonstrated energy capture at a peak efficiency of 65 percent and a minimum efficiency of 50 percent. The following experiments involved a true plasma direct converter that was tested on the Tandem Mirror Experiment (TMX), an operating magnetic mirror fusion reactor. In the experiment, the plasma moved along diverging field lines, spreading it out and converting it into a forward moving beam with a Debye length of a few centimeters. Suppressor grids then reflect the electrons, and collector anodes recovered the ion energy by
slowing them down and collecting them at high-potential plates. This machine demonstrated an energy capture efficiency of 48 percent. However, Marshall Rosenbluth argued that keeping the plasma's neutral charge over the very short Debye length distance would be very challenging in practice, though he said that this problem would not occur in every version of this technology.
The Venetian Blind converter can operate with 100 to 150 keV D-T plasma, with an efficiency of about 60% under conditions compatible with economics, and an upper technical conversion efficiency up to 70% ignoring economic limitations. | 3 | Nuclear Fusion |
Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium (hydrogen isotopes), combine to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released.
A nuclear fusion process that produces atomic nuclei lighter than iron-56 or nickel-62 will generally release energy. These elements have a relatively small mass and a relatively large binding energy per nucleon. Fusion of nuclei lighter than these releases energy (an exothermic process), while the fusion of heavier nuclei results in energy retained by the product nucleons, and the resulting reaction is endothermic. The opposite is true for the reverse process, called nuclear fission. Nuclear fusion uses lighter elements, such as hydrogen and helium, which are in general more fusible; while the heavier elements, such as uranium, thorium and plutonium, are more fissionable. The extreme astrophysical event of a supernova can produce enough energy to fuse nuclei into elements heavier than iron. | 3 | Nuclear Fusion |
This energy barrier is given by the electric potential energy:
where
:ε is the permittivity of free space;
:q, q are the charges of the interacting particles;
:r is the interaction radius.
A positive value of U is due to a repulsive force, so interacting particles are at higher energy levels as they get closer. A negative potential energy indicates a bound state (due to an attractive force).
The Coulomb barrier increases with the atomic numbers (i.e. the number of protons) of the colliding nuclei:
where e is the elementary charge, and Z the corresponding atomic numbers.
To overcome this barrier, nuclei have to collide at high velocities, so their kinetic energies drive them close enough for the strong interaction to take place and bind them together.
According to the kinetic theory of gases, the temperature of a gas is just a measure of the average kinetic energy of the particles in that gas. For classical ideal gases the velocity distribution of the gas particles is given by Maxwell–Boltzmann. From this distribution, the fraction of particles with a velocity high enough to overcome the Coulomb barrier can be determined.
In practice, temperatures needed to overcome the Coulomb barrier turned out to be smaller than expected due to quantum mechanical tunnelling, as established by Gamow. The consideration of barrier-penetration through tunnelling and the speed distribution gives rise to a limited range of conditions where fusion can take place, known as the Gamow window.
The absence of the Coulomb barrier enabled the discovery of the neutron by James Chadwick in 1932. | 3 | Nuclear Fusion |
Research centered on three plasma confinement designs; the stellarator headed by Lyman Spitzer at the Princeton Plasma Physics Laboratory, the toroidal pinch or Perhapsatron led by James Tuck at the Los Alamos National Laboratory and the magnetic mirror devices at the Livermore National Laboratory led by Richard F. Post. By June, 1954 a preliminary study had been completed for a full scale "Model D" stellarator that would be over long and produce 5,000 MW of electricity at a capital cost of $209 per kilowatt. However, each concept encountered unanticipated problems, in the form of plasma instabilities that prevented the requisite temperatures and pressures from being achieved, and it eventually became clear that sustained hydrogen fusion would not be developed quickly. Strauss left AEC in 1958 and his successor did not share Strauss' enthusiasm for fusion research. Consequently, Project Sherwood was relegated from a crash program to one that concentrated on basic research. | 3 | Nuclear Fusion |
Martin Fleischmann of the University of Southampton and Stanley Pons of the University of Utah hypothesized that the high compression ratio and mobility of deuterium that could be achieved within palladium metal using electrolysis might result in nuclear fusion. To investigate, they conducted electrolysis experiments using a palladium cathode and heavy water within a calorimeter, an insulated vessel designed to measure process heat. Current was applied continuously for many weeks, with the heavy water being renewed at intervals. Some deuterium was thought to be accumulating within the cathode, but most was allowed to bubble out of the cell, joining oxygen produced at the anode. For most of the time, the power input to the cell was equal to the calculated power leaving the cell within measurement accuracy, and the cell temperature was stable at around 30 °C. But then, at some point (in some of the experiments), the temperature rose suddenly to about 50 °C without changes in the input power. These high temperature phases would last for two days or more and would repeat several times in any given experiment once they had occurred. The calculated power leaving the cell was significantly higher than the input power during these high temperature phases. Eventually the high temperature phases would no longer occur within a particular cell.
In 1988, Fleischmann and Pons applied to the United States Department of Energy for funding towards a larger series of experiments. Up to this point they had been funding their experiments using a small device built with $100,000 out-of-pocket. The grant proposal was turned over for peer review, and one of the reviewers was Steven Jones of Brigham Young University. Jones had worked for some time on muon-catalyzed fusion, a known method of inducing nuclear fusion without high temperatures, and had written an article on the topic entitled "Cold nuclear fusion" that had been published in Scientific American in July 1987. Fleischmann and Pons and co-workers met with Jones and co-workers on occasion in Utah to share research and techniques. During this time, Fleischmann and Pons described their experiments as generating considerable "excess energy", in the sense that it could not be explained by chemical reactions alone. They felt that such a discovery could bear significant commercial value and would be entitled to patent protection. Jones, however, was measuring neutron flux, which was not of commercial interest. To avoid future problems, the teams appeared to agree to publish their results simultaneously, though their accounts of their 6 March meeting differ. | 3 | Nuclear Fusion |
A second type of electrostatic converter initially proposed by Post, then developed by Barr and Moir, is the Periodic Electrostatic Focusing concept. Like the Venetian Blind concept, it is also a direct collector, but the collector plates are disposed in many stages along the longitudinal axis of an electrostatic focusing channel. As each ion is decelerated along the channel toward zero energy, the particle becomes "over-focused" and is deflected sideways from the beam, then collected. The Periodic Electrostatic Focusing converter typically operates with a 600 keV D-T plasma (as low as 400 keV and up to 800 keV) with efficiency of about 60% under conditions compatible with economics, and an upper technical conversion efficiency up to 90% ignoring economic limitations. | 3 | Nuclear Fusion |
Germicidal lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. If the quartz envelope transmits shorter wavelengths, such as the 185 nm mercury emission line, they can also be used wherever ozone is desired, for example, in the sanitizing systems of hot tubs and aquariums. They are also used by geologists to provoke fluorescence in mineral samples, aiding in their identification. In this application, the light produced by the lamp is usually filtered to remove as much visible light as possible, leaving just the UV light. Germicidal lamps are also used in waste water treatment in order to kill microorganisms.
The light produced by germicidal lamps is also used to erase EPROMs; the ultraviolet photons are sufficiently energetic to allow the electrons trapped on the transistors' floating gates to tunnel through the gate insulation, eventually removing the stored charge that represents binary ones and zeroes. | 8 | Ultraviolet Radiation |
Probiotics are increasingly being used in numerous dairy products such as ice cream, milk powders, yoghurts, frozen dairy desserts and cheese due to their important health benefits. But, low viability of probiotic bacteria in the food still remains a major hurdle. The pH, dissolved oxygen content, titratable acidity, storage temperature, species and strains of associative fermented dairy product organisms and concentration of lactic and acetic acids are some of the factors that greatly affect the probiotic viability in the product. As set by Food and Agriculture Organization (FAO) of the United Nations and the World Health Organization (WHO), the standard in order to be considered a health food with probiotic addition, the product should contain per gram at least 10-10 cfu of viable probiotic bacteria. It is necessary that the bacterial cells remain stable and healthy in the manufactured product, are sufficiently viable while moving through the upper digestive tract and are able to provide positive effects upon reaching the intestine of the host.
Cell microencapsulation technology has successfully been applied in the food industry for the encapsulation of live probiotic bacteria cells to increase viability of the bacteria during processing of dairy products and for targeted delivery to the gastrointestinal tract.
Apart from dairy products, microencapsulated probiotics have also been used in non-dairy products, such as [https://web.archive.org/web/20101123210115/http://integratedhealth.com/hpdspec/therasweet.htm TheresweetTM] which is a sweetener. It can be used as a convenient vehicle for delivery of encapsulated Lactobacillus to the intestine although it is not itself a dairy product. | 2 | Tissue Engineering |
The use of natural materials in scaffolds has its disadvantages. Usually, they are expensive, not available in large quantities and they have the risk of disease transmission. This has led to the development of synthetic scaffolds.
When producing synthetic scaffolds there is full control over their properties. For example, they can be made to have good mechanical properties and the right biodegradability. When it comes to synthetic scaffolds thickness, porosity and pore size are important factors for controlling connective tissue formation.
Examples of synthetic scaffolds are:
* Polyethylene terephthalate membranes (PET membranes)
* Polycarbonate-permeable membranes (PC membranes)
* Porous polylactic glycolic acid (PLGA)
Historical use of electrospinning to produce synthetic scaffolds dates back to at least the late 1980s when Simon showed that technology could be used to produce nano- and submicron-scale fibrous scaffolds from polymer solutions specifically intended for use as in vitro cell and tissue substrates. This early use of electrospun lattices for cell culture and tissue engineering showed that various cell types would adhere to and proliferate upon polycarbonate fibers. It was noted that as opposed to the flattened morphology typically seen in 2D culture, cells grown on the electrospun fibers exhibited a more rounded 3-dimensional morphology generally observed of tissues in vivo. | 2 | Tissue Engineering |
Because the bubble collapse occurs within microseconds, the hot spot theory states that the thermal energy results from an adiabatic bubble collapse. In 1950 it was assumed that the bubble internal temperatures were as high as 10,000 K at the collapse of a spherical symmetric bubble. In the 1990s, sonoluminescence spectra were used by Suslick to measure effective emission temperatures in bubble clouds (multibubble sonoluminescence) of 5000 K, and more recently temperatures as high as 20,000 K in single bubble cavitation. | 0 | Luminescence |
Researchers have also been able to develop alginate microcapsules with an altered form of alginate with enhanced biocompatibility and higher resistance to osmotic swelling.
Another approach to increasing the biocompatibility of the membrane biomaterial is through surface modification of the capsules using peptide and protein molecules which in turn controls the proliferation and rate of differentiation of the encapsulated cells. One group that has been working extensively on coupling the amino acid sequence Arg-Gly-Asp (RGD) to alginate hydrogels demonstrated that the cell behavior can be controlled by the RGD density coupled on the alginate gels. Alginate microparticles loaded with myoblast cells and functionalized with RGD allowed control over the growth and differentiation of the loaded cells.
Another vital factor that controls the use of cell microcapsules in clinical applications is the development of a suitable immune-compatible polycation to coat the otherwise highly porous alginate beads and thus impart stability and immune protection to the system. Poly-L-lysine is the most commonly used polycation but its low biocompatibility restricts the successful clinical use of these PLL formulated microcapsules which attract inflammatory cells thus inducing necrosis of the loaded cells. Studies have also shown that alginate-PLL-alginate (APA) microcapsules demonstrate low mechanical stability and short term durability. Thus several research groups have been looking for alternatives to PLL and have demonstrated promising results with poly-L-ornithine and poly(methylene-co-guanidine) hydrochloride by fabricating durable microcapsules with high and controlled mechanical strength for cell encapsulation.
Several groups have also investigated the use of chitosan which is a naturally derived polycation as a potential replacement for PLL to fabricate alginate-chitosan (AC) microcapsules for cell delivery applications. However, studies have also shown that the stability of this AC membrane is again limited and one group demonstrated that modification of this alginate-chitosan microcapsules with genipin, a naturally occurring iridoid glucosid from gardenia fruits, to form genipin cross-linked alginate-chitosan (GCAC) microcapsules could augment stability of the cell loaded microcapsules. | 2 | Tissue Engineering |
Julie Elizabeth Gough is a Professor of Biomaterials and Tissue Engineering at The University of Manchester. She specializes on controlling cellular responses at the cell-biomaterial interface by engineering defined surfaces for mechanically sensitive connective tissues. | 2 | Tissue Engineering |
Select filter cloth based on the type filter aid used (refer Filter aid selection), adjust the advancing knife to optimize the knife advance rate per drum revolution. (Detail explained in Advance blade section) | 5 | Separation Processes |
Attempts to create organs in vitro started with one of the first dissociation-reaggregation experiments where Henry Van Peters Wilson demonstrated that mechanically dissociated sponge cells can reaggregate and self-organize to generate a whole organism. In the subsequent decades, multiple labs were able to generate different types of organs in vitro through the dissociation and reaggregation of organ tissues obtained from amphibians and embryonic chicks. The formation of first tissue-like colonies in vitro was observed for the first time by co-culturing keratinocytes and 3T3 fibroblasts. The phenomena of mechanically dissociated cells aggregating and reorganizing to reform the tissue they were obtained from subsequently led to the development of the differential adhesion hypothesis by Malcolm Steinberg. With the advent of the field of stem cell biology, the potential of stem cells to form organs in vitro was realized early on with the observation that when stem cells form teratomas or embryoid bodies, the differentiated cells can organize into different structures resembling those found in multiple tissue types. The advent of the field of organoids, started with a shift from culturing and differentiating stem cells in two dimensional (2D) media, to three dimensional (3D) media to allow for the development of the complex 3-dimensional structures of organs. Utilization of 3D media culture media methods for the structural organization was made possible with the development of extracellular matrices (ECM). In the late 1980s, Bissell and colleagues showed that a laminin rich gel can be used as a basement membrane for differentiation and morphogenesis in cell cultures of mammary epithelial cells. Since 1987, researchers have devised different methods for 3D culturing, and were able to utilize different types of stem cells to generate organoids resembling a multitude of organs. In the 1990s, in addition to their role in physical support, the role of ECM components in gene expression by their interaction with integrin-based focal adhesion pathways was reported. In 2006, Yaakov Nahmias and David Odde showed the self-assembly of vascular liver organoid maintained for over 50 days in vitro. In 2008, Yoshiki Sasai and his team at RIKEN institute demonstrated that stem cells can be coaxed into balls of neural cells that self-organize into distinctive layers. In 2009 the Laboratory of Hans Clevers at Hubrecht Institute and University Medical Center Utrecht, Netherlands, showed that single LGR5-expressing intestinal stem cells self-organize to crypt-villus structures in vitro without necessity of a mesenchymal niche, making them the first organoids. In 2010, Mathieu Unbekandt & Jamie A. Davies demonstrated the production of renal organoids from murine fetus-derived renogenic stem cells. In 2014, Qun Wang and co-workers engineered collagen-I and laminin based gels and synthetic foam biomaterials for the culture and delivery of intestinal organoids and encapsulated DNA-functionalized gold nanoparticles into intestinal organoids to form an intestinal Trojan horse for drug delivery and gene therapy. Subsequent reports showed significant physiological function of these organoids in vitro and in vivo.
Other significant early advancements included in 2013, Madeline Lancaster at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences established a protocol starting from pluripotent stem cells to generate cerebral organoids that mimic the developing human brain's cellular organization. Meritxell Huch and Craig Dorrell at Hubrecht Institute and University Medical Center Utrecht demonstrated that single Lgr5+ cells from damaged mouse liver can be clonally expanded as liver organoids in Rspo1-based culture medium over several months. In 2014, Artem Shkumatov et al. at the University of Illinois at Urbana-Champaign demonstrated that cardiovascular organoids can be formed from ES cells through modulation of the substrate stiffness, to which they adhere. Physiological stiffness promoted three-dimensionality of EBs and cardiomyogenic differentiation. In 2015, Takebe et al. demonstrated a generalized method for organ bud formation from diverse tissues by combining pluripotent stem cell-derived tissue-specific progenitors or relevant tissue samples with endothelial cells and mesenchymal stem cells. They suggested that the less mature tissues, or organ buds, generated through the self-organized condensation principle might be the most efficient approach toward the reconstitution of mature organ functions after transplantation, rather than condensates generated from cells of a more advanced stage. | 2 | Tissue Engineering |
Because of its ability to cause chemical reactions and excite fluorescence in materials, ultraviolet radiation has a number of applications. The following table gives some uses of specific wavelength bands in the UV spectrum.
* 13.5 nm: Extreme ultraviolet lithography
* 30–200 nm: Photoionization, ultraviolet photoelectron spectroscopy, standard integrated circuit manufacture by photolithography
* 230–365 nm: UV-ID, label tracking, barcodes
* 230–400 nm: Optical sensors, various instrumentation
* 240–280 nm: Disinfection, decontamination of surfaces and water (DNA absorption has a peak at 260 nm), germicidal lamps
* 200–400 nm: Forensic analysis, drug detection
* 270–360 nm: Protein analysis, DNA sequencing, drug discovery
* 280–400 nm: Medical imaging of cells
* 300–320 nm: Light therapy in medicine
* 300–365 nm: Curing of polymers and printer inks
* 350–370 nm: Bug zappers (flies are most attracted to light at 365 nm) | 8 | Ultraviolet Radiation |
Regenerative medicine has been studied by dentists to find ways that damaged teeth can be repaired and restored to obtain natural structure and function. Dental tissues are often damaged due to tooth decay, and are often deemed to be irreplaceable except by synthetic or metal dental fillings or crowns, which requires further damage to be done to the teeth by drilling into them to prevent the loss of an entire tooth.
Researchers from King's College London have created a drug called Tideglusib that claims to have the ability to regrow dentin, the second layer of the tooth beneath the enamel which encases and protects the pulp (often referred to as the nerve).
Animal studies conducted on mice in Japan in 2007 show great possibilities in regenerating an entire tooth. Some mice had a tooth extracted and the cells from bioengineered tooth germs were implanted into them and allowed to grow. The result were perfectly functioning and healthy teeth, complete with all three layers, as well as roots. These teeth also had the necessary ligaments to stay rooted in its socket and allow for natural shifting. They contrast with traditional dental implants, which are restricted to one spot as they are drilled into the jawbone.
A persons baby teeth are known to contain stem cells that can be used for regeneration of the dental pulp after a root canal treatment or injury. These cells can also be used to repair damage from periodontitis, an advanced form of gum disease that causes bone loss and severe gum recession. Research is still being done to see if these stem cells are viable enough to grow into completely new teeth. Some parents even opt to keep their childrens baby teeth in special storage with the thought that, when older, the children could use the stem cells within them to treat a condition. | 2 | Tissue Engineering |
Glycation (non-enzymatic glycosylation) is the covalent attachment of a sugar to a protein, lipid or nucleic acid molecule. Typical sugars that participate in glycation are glucose, fructose, and their derivatives. Glycation is the non-enzymatic process responsible for many (e.g. micro and macrovascular) complications in diabetes mellitus and is implicated in some diseases and in aging. Glycation end products are believed to play a causative role in the vascular complications of diabetes mellitus.
In contrast with glycation, glycosylation is the enzyme-mediated ATP-dependent attachment of sugars to protein or lipid. Glycosylation occurs at defined sites on the target molecule. It is a common form of post-translational modification of proteins and is required for the functioning of the mature protein. | 6 | Carbohydrates |
Amylopectin-based fibers have been fabricated mainly by blending native or modified starches with polymers, plasticizers, cross-linkers, or other additives. Most amylopectin-based fibers are fabricated by electro-wet-spinning, however, the method is demonstrated to be suitable for starches with amylopectin content below 65% and sensitive to amylopectin content of starches. Electrospinning allows for amylopectin to coagulate and form a filament. Fibrous starches induce a more dense material, which can optimize the mechanical properties of starch. Fibers in biomaterials can be used for bone tissue engineering as suitable environment for bone tissue repair and regeneration. Natural bone is a complex composite material composed of an extracellular matrix of mineralized fibers containing living cells and bioactive molecules. Consequently, the use of fibers in biomaterial-based scaffolds offers a wide variety of opportunities to replicate the functional performance of bone. In the last decade, fiber-based techniques such as weaving, knitting, braiding, as well as electrospinning, and direct writing have emerged as promising platforms for making 3D tissue constructs. | 6 | Carbohydrates |
*Light-emitting diodes (LEDs) emit light via electro-luminescence.
*Phosphors, materials that emit light when irradiated by higher-energy electromagnetic radiation or particle radiation
*Laser, and lamp industry
*Phosphor thermometry, measuring temperature using phosphorescence
*Thermoluminescence dating
*Thermoluminescent dosimeter
*Non-disruptive observation of processes within a cell.
Luminescence occurs in some minerals when they are exposed to low-powered sources of ultraviolet or infrared electromagnetic radiation (for example, portable UV lamps) at atmospheric pressure and atmospheric temperatures. This property of these minerals can be used during the process of mineral identification at rock outcrops in the field or in the laboratory. | 0 | Luminescence |
The basic room purge equation is used in industrial hygiene. It determines the time required to reduce a known vapor concentration existing in a closed space to a lower vapor concentration. The equation can only be applied when the purged volume of vapor or gas is replaced with "clean" air or gas. For example, the equation can be used to calculate the time required at a certain ventilation rate to reduce a high carbon monoxide concentration in a room.
Sometimes the equation is also written as:
where
*D = time required; the unit of time used is the same as is used for Q
*V = air or gas volume of the closed space or room in cubic feet, cubic metres or litres
*Q = ventilation rate into or out of the room in cubic feet per minute, cubic metres per hour or litres per second
*C = initial concentration of a vapor inside the room measured in ppm
*C = final reduced concentration of the vapor inside the room in ppm | 5 | Separation Processes |
Fluorescent materials are also very widely used in numerous applications in molecular biology, often as "tags" which bind themselves to a substance of interest (for example, DNA), so allowing their visualization.
Thousands of moth and insect collectors all over the world use various types of black lights to attract moth and insect specimens for photography and collecting. It is one of the preferred light sources for attracting insects and moths at night. Black light can also be used to see animal excreta such as urine and vomit that is not always visible to the naked eye. | 8 | Ultraviolet Radiation |
A group of researchers at Georgia Tech made dye-sensitized solar cells with a higher effective surface area by wrapping the cells around a quartz optical fiber. The researchers removed the cladding from optical fibers, grew zinc oxide nanowires along the surface, treated them with dye molecules, surrounded the fibers by an electrolyte and a metal film that carries electrons off the fiber. The cells are six times more efficient than a zinc oxide cell with the same surface area. Photons bounce inside the fiber as they travel, so there are more chances to interact with the solar cell and produce more current. These devices only collect light at the tips, but future fiber cells could be made to absorb light along the entire length of the fiber, which would require a coating that is conductive as well as transparent. Max Shtein of the University of Michigan said a sun-tracking system would not be necessary for such cells, and would work on cloudy days when light is diffuse. | 8 | Ultraviolet Radiation |
Very hot objects emit UV radiation (see black-body radiation). The Sun emits ultraviolet radiation at all wavelengths, including the extreme ultraviolet where it crosses into X-rays at 10 nm. Extremely hot stars (such as O- and B-type) emit proportionally more UV radiation than the Sun. Sunlight in space at the top of Earth's atmosphere (see solar constant) is composed of about 50% infrared light, 40% visible light, and 10% ultraviolet light, for a total intensity of about 1400 W/m in vacuum.
The atmosphere blocks about 77% of the Suns UV, when the Sun is highest in the sky (at zenith), with absorption increasing at shorter UV wavelengths. At ground level with the sun at zenith, sunlight is 44% visible light, 3% ultraviolet, and the remainder infrared. Of the ultraviolet radiation that reaches the Earths surface, more than 95% is the longer wavelengths of UVA, with the small remainder UVB. Almost no UVC reaches the Earth's surface. The fraction of UVA and UVB which remains in UV radiation after passing through the atmosphere is heavily dependent on cloud cover and atmospheric conditions. On "partly cloudy" days, patches of blue sky showing between clouds are also sources of (scattered) UVA and UVB, which are produced by Rayleigh scattering in the same way as the visible blue light from those parts of the sky. UVB also plays a major role in plant development, as it affects most of the plant hormones. During total overcast, the amount of absorption due to clouds is heavily dependent on the thickness of the clouds and latitude, with no clear measurements correlating specific thickness and absorption of UVA and UVB.
The shorter bands of UVC, as well as even more-energetic UV radiation produced by the Sun, are absorbed by oxygen and generate the ozone in the ozone layer when single oxygen atoms produced by UV photolysis of dioxygen react with more dioxygen. The ozone layer is especially important in blocking most UVB and the remaining part of UVC not already blocked by ordinary oxygen in air. | 8 | Ultraviolet Radiation |
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