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排序方式: 共有144条查询结果,搜索用时 15 毫秒
31.
Saraf Madhusudan N. Birajdar Pramod G. Loya Punnamchand Mukherjee Siddharth A. 《平面色谱法杂志一现代薄层色谱法》2007,20(3):203-207
JPC – Journal of Planar Chromatography – Modern TLC - Epalrestat is a new drug for diabetic neuropathy. A new, simple, rapid very sensitive, and accurate high performance thin-layer... 相似文献
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Amber Vyas Shailendra Saraf Swarnlata Saraf 《Journal of inclusion phenomena and macrocyclic chemistry》2010,66(3-4):251-259
The purpose of the present work was to design and investigate the potential of novel hydroxylpropyl-beta-cyclodextrin (HP-β-CD) and chitosan nanocarriers (NCs) for effective delivery of model, poorly water soluble drug simvastatin. The prepared system was characterized for particle size, particle size distribution (PDI), zeta potential, differential scanning calorimetery, x-ray diffraction, encapsulation efficiency and drug release studies. The results revealed that among the selected ratios of tripolyphosphate/chitosan, ratio 1:4 and 1:5 proved to be optimum in terms of particle size, particle distribution and drug release profile. The average size of nanoparticles increased from 516 to 617 and 464 to 562 nm for ratio 1:4 and 1:5 with increase in drug/HP-β-CD amount. To assess interactions and whether the simvastatin was incorporated in the NCs in its crystalline or amorphous form DSC and XRD were performed. These results suggest that the encapsulation process produces a marked decrease in crystallinity of simvastatin and/or confers to a nearly amorphous state of drug in NCs. Results reveled that with increase in the amount of HP-β-CD/drug the final loading of the NCs increased due to increased solubilization of simvastatin in the presence of HP-β-CD. The in vitro release profile of prepared NCs showed initial fast release (burst effect) followed by a delayed release pattern. In conclusion, these nanocarriers constitute a novel and efficient system for encapsulation and oral delivery of poorly soluble drugs. 相似文献
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The single crystals of Lead Iodide have been grown by gel method. X‐ray diffraction studies on these crystals shows that the lattice parameters of grown crystals are almost matching with reported values. The results of detailed studies made on the microstructures of Lead Iodide crystals, have been described. The observations of the faces of these crystals revealed that they have grown by layer as well as spiral mechanisms. The probable role of these parameters is explained along with the surface microstructures on these various shaped crystals. 相似文献
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Experimental data of the dynamic viscoelastic properties, storage modulus (G′), loss modulus (G′′), and phase shift (δ) as well as of the viscosity, η, are reported for the polymerization of a free radical polymerization
system (methyl methacrylate) which exhibits the Trommsdorff effect. A rheometer-reactor assembly developed in our laboratory
is used for this purpose. It is observed that in the early stages of reaction, data lie in the terminal zone. As the polymerization
progresses, the Trommsdorff effect leads to a sharp increase in both the polymer concentration and the weight average molecular
weight, and the viscoelastic properties then lie in the entanglement zone. A modulus crossover point (when G′ = G′′) is identified that could be used as an identification of the point where the Trommsdorff effect starts assuming significance.
Received: 17 September 1998 Accepted: 9 December 1998 相似文献
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The article describes alternative method for the synthesis of (±) 9-demethoxyeleutherin and (±) 9-demethoxyisoeleutherin, the analogs of naturally occurring pyranonaphthoquinones antibiotics eleutherin and isoeleutherin. This methodology has provided the target molecules using a shorter route involving five simple chemical transformations with Nef reaction as a key step. All the intermediates and target molecules were completely characterized by spectral techniques and confirmed by comparison with literature data. Further we have extended Nef protocol toward formal synthesis of naturally occuring pyranonaphthoquinone pentalongin. We accomplished synthesis of of 2-(1,4-dimethoxynaphthalen-2-yl)acetic acid devoid of very toxic cyanide intermediates, which has been converted into pentalongin. 相似文献
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H. Saraf K. T. Ramesh A. M. Lennon A. C. Merkle J. C. Roberts 《Experimental Mechanics》2007,47(3):439-449
Traditionally, Kolsky bars are used to study the dynamic response of hard materials in uniaxial compression, tension or torsion.
We present modifications to the technique that allow loading of a soft tissue specimen in (a) hydrostatic compression and
(b) simple shear. The first modification is designed to determine the pressure vs. volume behavior of each material, and thence
to extract a measure of the dynamic compressibility or equivalently of the bulk modulus. The second modification is designed
to develop the shear stress versus shear strain behavior for a near-simple shear experiment. The critically important questions
of the proper acquisition of human tissue samples and protocols for appropriate experimentation have also been addressed.
The experimental techniques and the results are discussed in detail and the results compared to finite element simulations.
We present examples of the dynamic response of typical tissue simulants as well as human liver and stomach tissues. 相似文献