نتایج جستجو برای: solvent 5 solvent and the third factor
تعداد نتایج: 21395426 فیلتر نتایج به سال:
adolescents and young adults and their problems is an issue whose importance is obvious to anyone because youth are the founders of our countrys future and requires proper planning to be on leisure. given the importance of leisure,this study to investigate needs assessment and planning how adolescents and young adults spend their leisure time in urban of case study of high school girls and boys...
p2o5-sio2 (30% w/w) was found to be a useful catalyst for the synthesis of various 2-substituted aryl benzimidazoles under solvent-less and in solvent conditions from o-phenylenediamine and aldehydes. the products were directly recrystallized from methanol.
the application of a comprehensive model of communicative language ability (cla) to language teaching and testing has always been an imperative in l2 education since hymess proposal of communicative competence in the 1970s. recent l2 research has clearly underscored the importance of sufficient pragmatics representation as an essential component of cla in pedagogical and testing practices in l2...
The solvent dielectric constant is considered an important factor in determining the redox potential of the heme-containing protein cytochrome c in solution. In this study, we investigate the electrochemical response of cytochrome c in aqueous/organic solvent mixtures (100% aqueous buffer, 30% acetonitrile, 40% dimethyl sulfoxide, and 50% methanol), reporting the redox potential (E degrees'), e...
in recent years many researchers have been focused on interaction of small molecules with dna. dna is generally the primary intracellular of anticancer drugs, so the interaction between small molecules and dna can cause dna damage in cancer cells, blocking the division of cancer cells and resulting in cell death. the flavonoids are a large group of polyphenolic natural products that are widely ...
Background: A syringe to syringe dispersive liquid phase micro-extraction-floating organic drop was applied and used for the simultaneous extraction and pre-concentration of trace amounts of amphetamine (AMP) and methamphetamine (MAMP) in urine samples. The extracted analytes were determined by high performance liquid chromatography along with diode array detection. Materials & Methods: In thi...
While the Stokes-Einstein (SE) equation predicts that the diffusion coefficient of a solute will be inversely proportional to the viscosity of the solvent, this relation is commonly known to fail for solutes, which are the same size or smaller than the solvent. Multiple researchers have reported that for small solutes, the diffusion coefficient is inversely proportional to the viscosity to a fr...
objective(s):the aim of this study was to improve flowability and compressibility characteristics of starch to use as a suitable excipient in direct compression tabletting. quasi-emulsion solvent diffusion was used as a crystal modification method. materials and methods: corn starch was dissolved in hydrochloric acid at 80˚c and then ethanol as a non-solvent was added with lowering temperature ...
Background and objectives: Colchicum kurdicum (Bornm.) Stef. is a flowering perennial monocotyledon plant that has many important bioactive compounds especially colchicine and colchicine derivatives. In this study, the ultrasound-assisted acidic-solvent extraction method coupled with response-surface method was presented as the successful method for large scale extract...
the synthesis of functionalized 2-oxo-2h-coumarin derivatives has been studied by a one-pot reaction of o-hydroxybenzaldehyde, ethyl 2-bromoacetate and triphenylphosphine in the presence of catalytic amount of triethyl amine in etoac, water or under solvent free conditions. we have found the best results obtained under solvent free condition.
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