includes infra-red rays and visible lights e.t.c Effects of ionizing radiations on organisms are extreme which includes: mutations‚ breakage of hydrogen bonds‚ oxidation of double bonds‚ polymerization of some molecules‚ generation of radicals like singlet oxygen and OH radicals‚ formation of thymine dimmers‚ breakage of tryptophan into toxic photoproducts .the most lethal effect of ultra violet radiation is that its wavelengths can be absorbed by the DNA (deoxyribonucleic acid) of most microbial cells
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eXPRESS Polymer Letters Vol.3‚ No.6 (2009) 366–375 Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2009.46 Starch-based completely biodegradable polymer materials D. R. Lu‚ C. M. Xiao*‚ S. J. Xu College of Material Science and Engineering of Huaqiao University‚ Quanzhou‚ 362021‚ P. R. China Received 21 February 2009; accepted in revised form 30 March 2009 Abstract. Starch is a natural polymer which possesses many unique properties and some shortcoming simultaneously
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comprised of a hydroxyl group –OH chemically bonded to a carbon. One of the simplest and most common esters is ethyl ethanoate‚ or ethyl acetate‚ a combination of ethanoic acid and ethanol. The ethyl ethanoate chemical reaction is C2H4O2 + CH3CH2OH C4H8O2 + H2O. As seen in this reaction‚ an acid and an alcohol are combining to form an ester‚ with a water molecule as a bi-product. The water molecule is lost from the reactants as the carboxylic acid in the reaction loses a –OH hydroxyl group and the
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carbon atom (designated 2’)‚ and ribose has a hydroxyl group atom there. Deoxyribose-containing nucleotides are the monomers of DNA RNA Nucleotide [pic] The left picture shows the nucleotide unit of RNA. Nucleotides differ from nucleosides in that they have phosphate groups. Nucleotides can exist in the mono-‚ di-‚ or tri-phosphorylated forms. The most common site of phosphorylation of nucleotides found in cells is the hydroxyl group attached to the 5’-carbon of the ribose
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Rusting of iron couplingCertification : It has been certified that Akash Sharma having CBSE Roll No. Studying in XII-A (Science)‚ during the academic year 2010-11 has completed a project on the Study of the Affect of Metal Coupling on the Rusting of Iron and has given satisfactory account of this in his project report Shri D.K Gupta External Examiner PGT Chemistry Signature Signature Declaration : I ‚ Akash Sharma of Class XII A (Science)
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The environmental problem I chose in my local area of Pennsville‚ New Jersey is the pollution of our water sources. The impact of the industrial discharge‚ pesticides‚ atmospheric deposition‚ and urban street run off is causing depleted oxygen levels‚ our fish to test positive for Polychlorinated Biphenyls (PCBs)‚ aquatic life impairment of Phosphorous and Total Suspended Solids (TSS)‚ Nitrogen contamination‚ and primary contact recreation to be contaminated by Enterococcus Bacteria and Fecal Coliform
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The ozone layer diminishes more each year. As the area of polar ozone depletion (commonly called the ozone hole) gets larger‚ additional ultraviolet rays are allowed to pass through. These rays cause cancer‚ cataracts‚ and lowered immunity to diseases.1 What causes the depletion of the ozone layer? In 1970‚ Crutzen first showed that nitrogen oxides produced by decaying nitrous oxide from soil-borne microbes react catalytically with ozone hastening its depletion. His findings started
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of their hydroxyl functional group. The location of this hydroxyl functional group will impact the molecular structure of the alcohol‚ making it either primary (1° )‚ secondary (2° )‚ or tertiary (3° ). If the OH is bonded to only one other carbon‚ it is a primary alcohol (eg. 1-butanol); if bonded to two other carbons‚ it is a secondary alcohol (eg. 2-butanol); if bonded to three other carbons‚ it is a tertiary alcohol (eg. 2-methyl-2-propanol). Due to the placement of the hydroxyl functional
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A General Review of Tetracyclines Antibiotics Chang Liu Instructor: Prof. Jasson Sello Department of Chemistry‚ Brown University Providence 02906‚ RI Tetracyclines are the first broad-spectrum antibiotic to be applied to clinic use. Nevertheless‚ the increasing incidence of bacterial resistance of tetracyclines led to a series of studies on the development of semisynthetic tetracyclines to circumvent the resistant organisms. In order to better design the structures of tetracycline derivatives
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Starch‚ glycogen and cellulose are all polymers of glucose. They differ in the type of glucose present and the bonds which link thr glucose monomers together. Starch and glycogen are made from alpha-glucose. This is an isomer of glucose in which the hydroxyl (-OH) group attached to carbon number 1 is below the plane of the ring. Starch is itself composed of two types of polymer:amylose and amylopectin. In amylose‚ the glucose monomers are linked by 1‚4 glycosidic bonds. This means that the bond connects
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