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11.
Jaroszewski JW Staerk D Holm-Móller SB Jensen TH Franzyk H Somanadhan B 《Natural product research》2005,19(3):291-294
Extract of Naravelia zeylanica (Ranunculaceae) yielded three simple benzamides, 3,4-methylenedioxybenzamide, 4-methoxybenzamide and 4-hydroxy-3-methoxybenzamide. These simple C6C1 metabolites have been encountered as natural products for the first time. The compounds were identified by direct comparison of their spectral (1H- and 13C-NMR) and chromatographic (GCMS) data with those of authentic samples. Authentic 4-hydroxy-3-methoxybenzamide was synthesized in one step by treatment of 4-hydroxy-3-methoxybenzonitrile with sodium perborate. Authentic 3,4-methylenedioxybenzamide was synthesized from the corresponding acid. 相似文献
12.
Appel DI Brinda B Markowitz JS Newcorn JH Zhu HJ 《Biomedical chromatography : BMC》2012,26(11):1364-1370
A simple, rapid and sensitive method for quantification of atomoxetine by liquid chromatography–tandem mass spectrometry (LC‐MS/MS) was developed. This assay represents the first LC‐MS/MS quantification method for atomoxetine utilizing electrospray ionization. Deuterated atomoxetine (d3‐atomoxetine) was adopted as the internal standard. Direct protein precipitation was utilized for sample preparation. This method was validated for both human plasma and in vitro cellular samples. The lower limit of quantification was 3 ng/mL and 10 nm for human plasma and cellular samples, respectively. The calibration curves were linear within the ranges of 3–900 ng/mL and 10 nm to 10 µm for human plasma and cellular samples, respectively (r2 > 0.999). The intra‐ and inter‐day assay accuracy and precision were evaluated using quality control samples at three different concentrations in both human plasma and cellular lysate. Sample run stability, assay selectivity, matrix effect and recovery were also successfully demonstrated. The present assay is superior to previously published LC‐MS and LC‐MS/MS methods in terms of sensitivity or the simplicity of sample preparation. This assay is applicable to the analysis of atomoxetine in both human plasma and in vitro cellular samples. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
13.
Gamma ray-induced F bands in melt grown mixed crystals of KCl and KBr are studied at room temperature. The effect of dislocations on F-centre density in mixed crystals has been discussed. In addition, the influence of composition of mixed crystals on F band parameters has been studied. The behaviour of observed F bands is correlated to local strained regions and to the configuration of F centre in mixed crystals. 相似文献
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Sathyapriya R Brinda KV Vishveshwara S 《Journal of chemical information and modeling》2006,46(1):123-129
The structure networks of DNA-binding proteins have been constructed and analyzed. The detailed analysis of the networks indicates a strong relation between the positions of the residues interacting with DNA and those that form extensive interactions within the protein structure (called hubs). This study shows that the functional residues in these proteins are held in place by efficient scaffolding of the structure using side-chain interactions, thus highlighting the role of these side-chain hubs with respect to the functional residues in the protein structure. 相似文献
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Jennifer D. Reid Daniel T. Holmes D. Randal Mason Brinda Shah Christoph H. Borchers 《Journal of the American Society for Mass Spectrometry》2010,21(10):1680-1686
The renin-angiotensin-aldosterone system (RAAS) plays an essential role in the regulation of plasma volume and arterial blood
pressure. One of the most common diseases of the RAAS is the autonomous production of aldosterone by the adrenal glands, caused
by either bilateral adrenal hyperplasia or an aldosterone-producing adenoma. This condition, known as primary aldosteronism,
is a treatable and often curable form of hypertension. The measurement of plasma renin activity (PRA), as determined by radioimmunoassay
for angiotensin I is essential to the diagnosis of primary aldosteronism. However, accurate determination of PRA is often
hampered by low plasma concentrations of angiotensin I. Here, we report the use of immuno-MALDI (iMALDI) as a highly sensitive
and specific method for the absolute quantitation of angiotensin I in plasma. iMALDI permits concentration determination by
affinity-capture of angiotensin I and a stable-isotopically labeled standard (SIS) peptide on immobilized anti-peptide antibodies.
The affinity beads are placed on the MALDI target, permitting automated analysis of large numbers of patient samples. Pretreatment
of the plasma is not required, and this method is suitable for the accurate determination of angiotensin I in whole plasma.
The calibration curve generated using this method was linear over a 50-fold concentration range in plasma, with a correlation
coefficient of 0.984. MS/MS sequence confirmation provides absolute specificity. The iMALDI angiotensin I assay, therefore,
has the potential to be developed into a method for determining PRA that has advantages in time, in specificity, and in safety. 相似文献
18.
Using recent results for the surface current density on cylindrical surfaces of arbitrary cross-section producing uniform
interior magnetic field and an assumed set of flux-fronts, solutions of Bean’s critical state model for cylindrical samples
with non-elliptic cross-section are presented. Magnetization hysteresis loops for two cross-sections with different aspect ratios are obtained.
A comparison with some exact results shows the limitations of this approach. 相似文献
19.
V. Gunasekar B. Divya K. Brinda J. Vijaykrishnan V. Ponnusami K. S. Rajan 《Journal of Sol-Gel Science and Technology》2013,68(1):60-66
The purpose of this study was to develop bio-inspired photocatalyst with solar light activity for textile dye degradation. Three TiO2 samples namely TiO2 (TiO2-A), biotemplated TiO2 (TiO2-B), and enzyme mediated Ag–TiO2 biotemplate (TiO2-C), were developed. The presence of anatase phase of TiO2 and silver in synthesized samples were confirmed using X-ray diffraction, field emission scanning electron microscopy, energy-dispersive spectroscopy, and UV–Vis–NIR spectroscopy. Photocatalytic efficiencies of these photocatalysts were evaluated by studying the oxidation of a commercial reactive dye (reactive black) under solar light irradiation in batch reactors. Photocatalytic efficiencies of the sample were compared using statistical tools like one-way ANOVA and Tukey test. The results confirmed that photocatalytic efficiency of TiO2-C was 40 % higher than that of TiO2-A under solar light irradiation. 相似文献
20.
The absolute configuration (via degradation and Marfey's derivatization studies) and the total synthesis of a novel antimalarial lipid-peptide isolated from Streptomyces sp. (IC(50) = 0.8 μM, Plasmodium falciparum 3D7) is disclosed. To this end, versatile stereocontrolled routes to nonproteinogenic amino acids (via catalytic Mannich, Sharpless methods) and enantiomeric trans fatty acids (via Evans alkylation, Kocienski-Julia olefination) have been developed. 相似文献