Ultraviolet light treatment

Typical biocides include hypochlorous acid, chlorine dioxide, hypobromus acid, hydrogen peroxide, ozone, ultraviolet-light treatment, phenolics, aldehydes, and quaternary ammonium compounds (Ref 73, 80). A brief description of each follows (Ref 73, 80). Hypochlorous acid is probably the most commonly used biocide and also one of the most powerful oxidizing agents. The sources of hypochlorous acid are chlorine gas and sodium hypochlorite. In aque-... 

Water treatment technologies consist of many steps, such as sedimentation, oxidation, coagulation, flocculation, filtration, flotation, ion exchange, adsorption, and reverse osmosis. They are intended for the destruction of water contaminants and their removal from treated water bulk. At that, water is disinfected by different methods, namely, chlorination, ozonation, ultraviolet light treatment, and ultrasound treatment. 

Disinfeetion. Chlorine, as gaseous chlorine or as the h5rpochlorite ion, is widely used as a disinfectant. However, its use in some cases can lead to the formation of toxic organic chlorides, and the discharge of excess chlorine can be harmful. Ozone as an alternative disinfectant leads to products that have a lower toxic potential. Treatment is enhanced by ultraviolet light. Indeed, disinfection can be achieved by ultravifflet light on its own. 

The basic function of lysis processes is to split molecules to permit further treatment. Hydrolysis is a chemical reaction in which water reacts with another substance. In the reaction, the water molecule is ionized while the other compound is split into ionic groups. Photolysis, another lysis process, breaks chemical bonds by irradiating a chemical with ultraviolet light. Catalysis uses a catalyst to achieve bond cleavage. 

When the chip is rinsed, fluorescent DNA remains bound to all those areas of the chip that have complementaiy sequences. Areas of the chip whose sequences are not complementary do not bind to the DNA. When the chip is rinsed and subsequently exposed to ultraviolet light, the areas with bound DNA fluoresce, generating light from each area to which the DNA has bound, hi contrast, areas of the chip that contain noncomplementary sequences remain dark. The fluorescence pattern reveals which protein synthesis processes have been modified in the cancerous cell, and this in turn helps physicians determine what treatment is most likely to be effective against the cancer. 

KATIYAR s K, PEREZ A and MUKHTAR H (2000b) Green tea polyphenol treatment to hiunan skin prevents formation of ultraviolet light B-induced pyrimidine dimers in DNA , Clin Cancer Res, 6 (10), 3864-9. 

Polyethylene remains unaffected an action with most acids, alkalis and aqueous solution. Strong oxidising agents like nitric acid and hydrogen peroxide, etc. cause deterioration, deterioration also take place with oxygen in presence of ultraviolet light hence antioxidants are added to the polymer. Polyethylene may be cross-linked by exposure to X-rays, Y-rays, fast electrons or by treatment with peroxides. 

Interactions with standard treatment (e.g., ultraviolet light)... 

In order to achieve complete destruction of biological contaminants in water through sonication very high ultrasonic intensities are necessary. Unfortunately this makes the technique expensive to use for general microbiological decontamination. However over the last two decades some conventional disinfection techniques involving chemicals, ultraviolet light and heat treatment have become less effective as some bacteria become more resistant. Such processes have become a focus for the use of sonication as an adjunct to other techniques. 

Somich, C.J., Kearney. P.C., Muldoon, M.T., and Elsasser, S. Enhanced soil degradation of alachlor by treatment with ultraviolet light and ozone, /. Agric. Food Chem., 36(6) 1322-1326, 1988. 

Members of the phosphoinositide (PI)-3 kinase family appear to be involved in the phosphorylation of H2A.X. The SQ motif matches a common target site for these kinases and the formation of y-H2A.X in response to double stranded breaks is inhibited by wortmannin, an inhibitor of PI-3 kinases [63]. Examination of cell lines deficient in the PI-3 kinase ATM indicated that it has a major role in phosphorylating H2A.X in response to double strand breaks [64]. ATM can phosphorylate H2A.X in vitro suggesting that it may directly phosphorylate H2A.X in vivo [64]. Another PI-3 kinase ATR appears to be involved in phosphorylating H2A.X in response to replicational stress induced by treatment of dividing cells with hydroxyurea or by irradiating them with ultraviolet light [65]. It has been hypothesized that PI-3 kinases such as ATM are recruited to, or activated at, the site of the double stranded break and then phosphorylate H2A.X molecules around the break point [40,64,66]. 

Conjugated double bonds were also reduced in methyl 3-methyl-2-buten-oate with tributylstamane on irradiation with ultraviolet light at 70° (yield of methyl isovalerate was 90%) [1071], and in diethyl maleate and diethyl fu-marate which afforded diethyl succinate in respective yields of 95% and 88% on treatment with chromous sulfate in dimethylformamide at room temperature [974,1072]. 

Phototoxicity Moderate-to-severe phototoxic reactions have occurred in patients exposed to direct or indirect sunlight or to artificial ultraviolet light (eg, sunlamps) during or following treatment with lomefloxacin, sparfloxacin, or ofloxacin. 

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