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排序方式: 共有193条查询结果,搜索用时 46 毫秒
61.
Mst. Sharmin Sultana Shimu Shafi Mahmud Trina Ekwati Tallei Saad Ahmed Sami Ahmad Akroman Adam Uzzal Kumar Acharjee Gobindo Kumar Paul Talha Bin Emran Shahriar Zaman Md. Salah Uddin Md. Abu Saleh Sultan Alshehri Mohammed M Ghoneim Maha Alruwali Ahmad J. Obaidullah Nabilah Rahman Jui Junghwan Kim Bonglee Kim 《Molecules (Basel, Switzerland)》2022,27(3)
62.
Dynamic Characteristics of a Microhollow Cathode Sustained Discharge with Split Third Electrodes for Potential Flow Application to Flow Velocimetry 下载免费PDF全文
The dynamic behavior of a microhollow cathode sustained discharge with split third electrodes is experimentally investigated. The sustained discharge swells isotropically in the presence of a small amount of argon gas flow that is not clearly detectable with a conventional single third electrode. At high flow rates, the sustained discharge transitions to a fast-moving constricted discharge with an are shape. The modified discharge structure causes a shift in current distribution over the third electrodes, and the current peak location varies linearly with the flow rate over a certain flow range. Such linear behavior may be applied to in situ flow velocity measurement. 相似文献
63.
64.
In the course of our studies on the chemical constituents of the leaves of Skimmia laureola, a new triterpene O-methyl cyclolaudenol (1) and a new coumarin, (+)-7-methoxy-6-(2'R-methoxy-3'-hydroxy-3'-methyl butyl) coumarin (2) were isolated. In addition five known coumarins, isogospherol (3), heraclenol (4), 5,8-dimethoxy coumarin-2H-1-benzopyran-2-one (5), 7-methoxy-6[2'-oxo-3'-methyl butyl] coumarin (6), and (+)-ulopterol (7) were also isolated for the first time from this plant. The structures were identified by spectroscopic studies and the stereochemistry at C-2' in compounds 3 and 4 were established by Horeau's procedure. 相似文献
65.
S. Chandrasekhar Ch. Narsihmulu S. Shameem Sultana M. Srinivasa Reddy 《Tetrahedron letters》2004,45(50):9299-9301
Iterative asymmetric allylations and ring-closing metathesis have been effectively performed for the first stereoselective total synthesis of (6S)-5,6-dihydro-6-[(2R)-2-hydroxy-6-phenylhexyl]-2H-pyran-2-one, a novel α,β-unsaturated-δ-lactone having antifungal activity, isolated from Ravensara crassifolia. 相似文献
66.
The current study evaluates the efficacy of Balsamodendron mukul Hook ex. Stocks, an indigenous plant, in the modulation of benzoyl peroxide (BPO) treated and ultraviolet (UV) light irradiated tumor promotional events. BPO is a well-known tumor promoter while UV radiations are capable of acting as complete carcinogens. Treatment of the dorsal portions of the mice skins with BPO (20 mg/0.2 ml/animal) and subsequent UV irradiation (0.420 J/m(2)/s) caused a significant depletion of reduced glutathione (GSH), it's metabolizing and phase II enzymes (p < 0.01). Also, down regulation of the activities of antioxidant enzymes and up regulation of ornithine decarboxylase activity and enhancement in the synthesis of DNA, malondialdehyde (MDA) and hydrogen peroxide (H(2)O(2)) was observed. However, topical pretreatment with the extract of B. mukul not only restored the content of GSH, MDA and H(2)O(2) but it also recovered the activities of above-mentioned enzymes (p < 0.05) and prevented synthesis of DNA (p < 0.05) significantly. Although the lower dose was not very effective, the higher dose showed promising results against oxidative stress and hyperproliferative response of BPO and UVB radiations. From the present data we conclude that B. mukul is potentially strong enough to modulate the events of skin tumor promotion. 相似文献
67.
Sultana N Schenkman JB Rusling JF 《Journal of the American Chemical Society》2005,127(39):13460-13461
This communication demonstrates direct electron delivery from electrodes to cyt P450 reductases in stable films ( approximately 100 nm thick) of genetically enriched CYP1A2 and CYP3A4 microsomes made by layer-by-layer assembly with polyions. Reversible voltammetry of films containing genetically enriched cyt P450 monooxygenase microsomes was shown to involve cyt P450 reductase by comparison with the pure rabbit reductase and by lack of characteristic reactions of iron heme enzymes, such as reaction of the FeII form with CO and catalytic electrochemical reduction of oxygen and hydrogen peroxide. The microsome films were activated electrochemically to catalyze styrene epoxidation, consistent with the pathway utilized in the human liver, although further work is required to establish this definitively. 相似文献
68.
Saha R Qaium MA Debnath D Younus M Chawdhury N Sultana N Kociok-Köhn G Ooi LL Raithby PR Kijima M 《Dalton transactions (Cambridge, England : 2003)》2005,(16):2760-2765
A series of cis-platinum ethynyl complexes with the general formula cis-[Pt(dppe)(C[triple bond]CR)2](dppe = 1,2-bis(diphenylphosphino)ethane; R = C6H4-p-NO2 1, C6H4-p-CH3 2, C6H4-p-C[triple bond]CH 3 and C6H4-p-C6H4-p-C[triple bond]CH 4) have been prepared by the coupling reaction of cis-[Pt(dppe)Cl2] with two equivalents of the appropriate alkyne. The new complexes have been fully characterized by spectroscopic techniques, and the cis square planar arrangement at the platinum centre has been confirmed by single-crystal X-ray diffraction studies of complexes 1, 2 and 4. The absorption spectra of the complexes 1-4 are dominated by a pi-->pi* band that contains some platinum (n + 1) p orbital character. The position of the band is dependent on the electron donating or withdrawing properties of the ethynyl substituents, R. Complex 1 displays a triplet emission in the green, at room temperature, while complexes 2-4, display singlet emissions in the blue. Again, the difference can be attributed to the nature of the R substituents. 相似文献
69.
Dr. Md Mokhlesur Rahman Irin Sultana Dr. Tianyu Yang Dr. Zhiqiang Chen Dr. Neeraj Sharma Dr. Alexey M. Glushenkov Prof. Ying Chen 《Angewandte Chemie (International ed. in English)》2016,55(52):16059-16063
A simple, cost‐effective, and easily scalable molten salt method for the preparation of Li2GeO3 as a new type of high‐performance anode for lithium‐ion batteries is reported. The Li2GeO3 exhibits a unique porous architecture consisting of micrometer‐sized clusters (secondary particles) composed of numerous nanoparticles (primary particles) and can be used directly without further carbon coating which is a common exercise for most electrode materials. The new anode displays superior cycling stability with a retained charge capacity of 725 mAh g?1 after 300 cycles at 50 mA g?1. The electrode also offers excellent rate capability with a capacity recovery of 810 mAh g?1 (94 % retention) after 35 cycles of ascending steps of current in the range of 25–800 mA g?1 and finally back to 25 mA g?1. This work emphasizes the importance of exploring new electrode materials without carbon coating as carbon‐coated materials demonstrate several drawbacks in full devices. Therefore, this study provides a method and a new type of anode with high reversibility and long cycle stability. 相似文献
70.
Studies on the petroleum ether soluble and insoluble fraction of ethanol extract of dried ground seeds of Piper nigrum resulted in the isolation and structure elucidation of 1 new and 11 known compounds which include 3 hitherto unreported constituents, namely, cinnamylideneacetone, 3,4-methylenedioxyphenylpropiophenone and 2-hydroxy-4,5-methylenedioxypropiophenone from this plant. 相似文献