The introduction of one acetyl group into the chymotrypsin molecule by reaction with p-nitrophenyl acetate gives rise to an enzymatically inactive monoacetylated protein that rapidly loses its acetyl group and becomes active again in solutions of dilute alkali or primary alcohols." 2 On the other hand, the well-known polyacetylation of proteins with acetic anhydride, as described by Fraenkel-Co...

due to special conditions of iran; i.e., neighboring to major centers of drug production in afghanistan during the last few decades, it was the passageway of the drug to europe. moreover, because of appropriate context of social, economic and cultural situations, there was an increased addiction and drug trafficking in iran. it is obvious that a lot of people would be involved directly and indi...

groundwater can be used directly or indirectly and any decline in its quality or quantity maynegatively impact the environment. through groundwater valuation, people are made aware of the fact thatgroundwater is not free of charge and therefore the significance of groundwater preservation is established. in this study, groundwater quality preservation value has been estimated for the city of ya...

assess the ecological effects of economic activity on the water, earth and man in the iranian economy approach using input - output tablewater is a vital resource for each biological and economic phenomenon. water is considered as a production input. production is not possible without water in all economic sectors. also, the environment including air, soil, fauna and plants utilize water in the...

organizations in private and public sector assign many projects in information technology (particularly software) field to contractors for implementation every year. previous experiences shows that most of these projects are stopped before finishing or cannot meet the expected results. based on studies related to this issue, many of failures depend on implementation contractor, directly or indi...