Ultraviolet Light UV

Many materials are subject to deterioration by ultraviolet light (UV). particularly many of the plastics and fiberglass materials. Fiberglass materials for outside use should be specified as UV-stabilized, and most plastics installed outdoors should be carbon-impregnated (black in color). It is particularly recommended that plastic cable ties, which secure cables in cable trays, be carbon-impregnated if installed outdoors. 

There are a few reports on the combined application of ultrasound and ultraviolet light (UV) for the destruction of chemical pollutants. A study of the oxidation of humic acid and trihalomethane precursors with ozone revealed that the most effective destruction of the organic carbon compounds was achieved when both uv and ultrasound were used in combination with ozonation [35]. In other cases e. g. the removal of 1,1,1-tri-chloroethane from aqueous solutions, the combined application of ultrasound and UV proved to be more efficient than the use of either technique individually [36]. 

Ultraviolet light (UV) is not effective enough to eliminate existing biofilm. When coupled with conventional thermal or chemical sanitization technologies, however, it is most effective and can prolong the interval between system sanitizations. 

The main sources of energy for curing epoxy adhesives by radiation are electron beam (EB) and ultraviolet light (uv). Both provide instantaneous curing of resins that polymerize from a liquid to a solid when irradiated. The uv systems account for approximately 85 percent of the market for radiant cured adhesives, EB systems account for about 10 percent, and the remainder are chiefly adhesives that can cure by exposure to both visible and infrared light. 

The physical agents of disinfection that have been used include ultraviolet light (UV), electron beam, gamma-ray irradiation, soniflcation, and heat (Bryan, 1990 Kawakami et al., 1978 Hashimoto et al., 1980). Gamma rays are emitted from radioisotopes, such as cobalt-60, which, because of their penetrating power, have been used to disinfect water and wastewater. The electron beam uses an electron generator. A beam of these electrons is then directed into a flowing water or wastewater to be disinfected. For the method to be effective, the liquid must flow in thin layers. 

In 1983, radiation curable 100 % solvent-free silicone acrylates were introduced into the market [4], This system provide the opportunity to be cured by either ultraviolet light (UV) or electron beam (EB). Similar in concept to peroxide initiation, silicone acrylate systems employ photoinitiators to generate free radicals and initiate cure, which is based on the polymerization of the acrylic C=C double bond via a radical chain reaction. 

Oral administration of a psoralen such as methoxsalen (8-methoxypsoralen), followed by exposure to ultraviolet light (UV-A) can be used to treat psoriasis, eczema, vitiligo and a number of other skin diseases. There is a small risk of inducing relatively easily treatable, non-melanoma, skin cancers and possibly, generally only after extensive treatment, a very small risk of malignant melanoma. Similar psoralens are the components, somewhat controversially, of some tanning aids. 

Ultraviolet light (UV) curable screen ink solder masks and photopolymerizable dry film solder masks have been available commercially since 1973 (5). These materials offer the PCB manufacturer many processing and production advantages relative to the conventional solvent-evaporative thermally cured solder masks. These products based on a new emerging technology have helped... 

Any change in a DNA sequence is a mutation. Mutations are classified according to the type of DNA alteration, including point mutations, deletion mutations, and insertion mutations. Ultraviolet light (UV) causes formation of pyrimidine dimers. Mistakes can be made during pyrimidine dimer re-... 

Thin-layer chromatography (TLC) is a good method for detecting the presence of cucurbitacins in a plant extract. The best results to date have been achieved using high-performance TLC (HPTLC) plates [41] with silica gel and chloroform-methanol (95 10) (Table 1) or toluene-ethyl acetate (25 75) as mobile phases [3,11]. Reversed-phase (RP) HPTLC plates with methanol-water (7 3) have also been used to separate cucurbitacins [3]. The compounds are easily detected with vanillin-sulphuric acid or vanillin-phosphoric acid reagents and ultraviolet light (UV) at 365 nm [11]. 

Among the environmental factors that influence the persistence of the carbamate insecticides in the aquatic environment is the decomposing of these compounds when influenced by solar radiations. Many organi-cides undergo changes after they are exposed to ultraviolet light (uv) and artificial or natural sunlight (7, 8, 9, 10). Therefore, the effect of... 

A human hereditary disease, xeroderma pigmentosum, is inherited as an autosomal recessive. It is characterized by the patient s extreme sensitivity to ultraviolet light (UV) and subsequent development of skin abnormalities, some of which may become malignant. Tissue culture cells derived from a homozygous recessive individual were more sensitive to UV than those from normal subjects (Gartler, 1964). Cultured cells from other xeroderma patients exhibit minimal DNA repair replication after UV (Cleaver, 1968), because the cells cannot perform the first step (excision... 

Vitamin D Vitamin D is produced when ultraviolet light (UV) shines on the skin and triggers the conversion of a steroid known as ergosterol to vitamin D. Its major role is to help the body use calcium, and a deficiency causes rickets in children, the same condition caused by calcium deficiency. Vitamin D supplements are rarely needed, except by those who are almost never exposed to the sun. Both vitamin A and vitamin D are essential to normal growth and development. Overdosage of vitamin D can have serious consequences, however. Calcium deposits can form in the kidney, lungs, or tympanic membrane of the ear (leading to deafness). Infants and small children are especially susceptible to vitamin D toxicity. 

Merck), sealed with eukitt (0. Kindler) and examined by phase-contrast and ultraviolet light (UV) optics in a Zeiss MC 63 stereomicroscope. 

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