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291.
A radiochemical method, based on the displacement of labelled zinc from Zn:PAN /1-/2-Pyridylazo/-2-Naphthol/ complex for the determination of uranium has been developed. 40–160 g of uranium U/VI/ in pH 7 ammonia buffer can be determined. the effect of diverse ions on the displacement reaction has also been studied.  相似文献   
292.
A sample of prehnite from Rayalaseema zone of Andhra Pradesh, India containing about 2.565 wt.% Fe(2)O(3) is used in the present work. The mineral has been characterized by EPMA, optical absorption, EPR, NIR and M?ssbauer techniques. M?ssbauer studies confirm the presence of iron as an impurity in two sites. An EPR study on powder sample confirm the presence of Fe(III) impurity in the mineral. Optical absorption spectrum also indicates that Fe(III) impurity is present in two sites with octahedral structure. NIR results are due to water fundamentals.  相似文献   
293.
Acetone chemical ionization mass mass spectra of four isomeric hexenyl acetates were investigated. The characteristic decomposition of [M + CH3CO]+ adducts in the field-free region reveals site-specific adduct formation of acetyl ion with the double bond and the acetoxy group.  相似文献   
294.
For the first time, interaction between non-toxic anthraquinone morindone with both natural and synthetic DNA duplexes has been demonstrated in this paper. Detailed analyses of the binding of morindone with DNA via UV?Cvis, FTIR, and circular dichroism spectroscopies were carried out. In addition, bioinformatics tools have been employed to scrutinize the binding of the dye with DNA in silico. Results represent morindone to be a better binder with a score of ?5.79 compared to EtBr (known mutagenic intercalator) recorded at ?5.02. Further interaction is accentuated by the microscope-assisted evidence of nuclear specific staining of tissues by morindone. The electrophoretic analysis reveals the efficacy endowed within morindone dye in rendering protection to DNA exposed to H2O2 damage and thereby conferring it safe to the nucleic acid. As DNA is often the target for majority of anticancer and antibiotic drugs, study on the interaction between molecules like morindone and DNA has relevance and implications in several biological applications including cancer therapy. Thus, we propose that morindone can also be harnessed as a diagnostic probe for DNA structure in addition to DNA-directed therapeutics.  相似文献   
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297.
The oxytriazole catalyst “pyrrolidine-HOBt” developed for asymmetric Michael addition of cyclohexanone to nitroolefins is now evaluated for the asymmetric Michael addition of aldehydes to nitroolefins under similar reaction conditions. The results of this study indicate that, the oxytriazole catalyst “pyrrolidine-HOBt” is equally effective in promoting the Michael addition of aldehydes to nitroolefins on employing benzoic acid as an additive. The desired products, γ-nitrocarbonyl compounds were obtained in good yields and high enantioselectivities.  相似文献   
298.
The synthesis of multivalent dendritic cluster glycosides of mannopyranosyl-6-phosphate is presented. Poly(amido amine)-based dendrimers of 0.5-3.5 generations, containing carboxylic acid peripheral functionalities, were utilized so as to install 4, 8, 16 and 32 mannopyranosyl-6-phosphate residues at the peripheries of the dendrimers. Amide bond formation between an amine-tethered mannopyranosyl-6-phosphate monomer unit and carboxylic acid-functionalized dendrimers was conducted to synthesize the dendritic cluster glycosides. The constitutions of the Man-6-P-containing dendrimers were assessed by 1H, 13C and 31P NMR spectroscopies and the sugar content analysis by a resorcinol assay. Preliminary biological studies with few newly synthesized Man-6-P-containing dendrimers showed that these compounds could bind the purified goat liver mannose 6-phosphate receptor (MPR 300) protein.  相似文献   
299.
N-Bromosuccinimide efficiently catalyzes the hydroamination and hydroalkoxylation of activated styrenes using tosylamides, carbamates, and alcohols as the nucleophiles to afford amino and ether derivatives, respectively. Both the processes give good to excellent yields of the products with 100% regioselectivity (Markovnikov fashion). [structure: see text]  相似文献   
300.
The design of a closed-loop platform-type robot manipulator using the finite element method is presented. The present approach aims at the optimization of the manipulator geometry and prediction ot the actuator parameters. Beam elements and triangular plate elements are used for the finite element model. Manipulators having six spherical-prismatic-spherical (6 SPS) pairs and of tetrahedron construction have been compared for their dynamic performance.  相似文献   
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