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21.
H. Ahmad M. S. Rahman M. A. J. Miah A. M. I. Ali 《Colloid and polymer science》2001,279(10):1039-1043
A series of poly(methyl methacrylate)/poly(methyl methacrylate-acrylamide) composite polymer particles was prepared with
varying proportions of acrylamide in the copolymer shell layer. Adsorption behaviors of some biomolecules and specific activity
of adsorbed trypsin were studied. The hydrophobic interaction between the composite polymer particle surfaces and biomolecules
decreased with increasing acrylamide content.
Received: 7 February 2001 Accepted: 16 May 2001 相似文献
22.
Choudhary MI Shah SA Musharraf SG Shaheen F Atta-Ur-Rahman 《Natural product research》2003,17(3):215-220
Transformation of dehydroepiandrosterone (DHEA) (1) was carried out by a plant pathogen Rhizopus stolonifer, which resulted in the production of seven metabolites. These metabolites were identified as 3beta,17beta-dihydroxyanandrost-5-ene (2), 3beta,17beta-dihydroxyandrost-4ene (3), 17beta-hydroxyandrost-4-ene-3-one (4), 3beta,11-dihydroxyandrost-4-ene-17-one (5), 3beta,7alpha-dihydroandrost-5-ene-17-one (6), 3A,7alpha,17beta-trihydroxyandrost-5-ene (7) and 11beta-hydroxyandrost-4,6-diene-3,17-dione (8). The structures of the transformed products were determined by the spectroscopic techniques. 相似文献
23.
Audouard C Fawcett J Griffith GA Kérourédan E Miah A Percy JM Yang H 《Organic letters》2004,6(23):4269-4272
Direct precursors to analogues of pentopyranoses, 6-deoxyhexoses, and hexoses, in which a CF(2) center replaces the pyranose oxygen, have been synthesized rapidly from trifluoroethanol. A simple scaleable allylation reaction delivers ethers which undergo dehydrofluorination/metalation, followed by addition to either acrolein or cinnamaldehyde, to afford allylic alcohols. Fluorine-assisted [3,3]-rearrangement followed by reduction with sodium borohydride delivers diols, which undergo RCM smoothly to afford cyclohexene diols. 相似文献
24.
Optical power limiting is the increase of optical absorption with light intensity. Pure crystalline potash alum was grown and optical absorption in dependences of the light intensity and thickness of the crystal was studied using laser light. The transmission of the crystals was found to increase with increasing light intensity. However, at higher light intensity, an increase of optical absorption with intensity was observed. The power limiting characteristics, e.g. linear transmission/dynamic range and saturation point, were found to be varied with thickness of the crystal. The findings resulting from this investigation might have potential applications in optical limiting. 相似文献
25.
Farzana Miah Hendrik Koliwer-Brandl Martin Rejzek Robert A. Field Rainer Kalscheuer Stephen Bornemann 《Chemistry & biology》2013,20(4):487-493
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26.
M. Idrish Miah 《Optik》2011,122(1):55-57
We study the nonlinear wave propagation in an inhomogeneous optical fiber core in the normal dispersive regime. In order to include the inhomogeneous physical effects, the nonlinear Schrödinger equation (NLSE), which governs the solitary pulse propagation in optical fiber, is modified by adding terms for phase modulation and power gain or loss. The modified NLSEs are bilinearized and exact dark soliton solutions are obtained. The results are discussed. 相似文献
27.
Preparation of Porous Titania Film by Modified Sol-Gel Method and its Application to Photocatalyst 总被引:2,自引:0,他引:2
Yusuf Miah Muhammed Imai Hiroaki Hirashima Hiroshi 《Journal of Sol-Gel Science and Technology》2002,25(1):65-74
Sol-Gel derived mesoporous titania films with controlled pore sizes were prepared by surfactant templating. The coating sol was obtained by hydrolysis of Ti(OC4H9)4 in ethanol/HCl solution. The gel films, prepared by spin coating on glass substrate, were dried after immersion in surfactant solutions under an atmospheric pressure. The porous films of anatase with columnar and rectangular structure were obtained after annealing at 500°C. The annealed films are transparent and 80–140 nm in thickness. Refractive indices of the films with surfactant immersion were 10–20% lower than those of the films without immersion. The spacing between the columns or rectangular grains and the grain shape were found to depend on the surfactant species. The pohoto-catalytic activity of the films for the oxidation of NO
x
was improved by the surfactant modification. 相似文献
28.
Sohan Md. Sohanur Rahman Hasan Mahedi Hossain Md. Forhad Sajib Salek Ahmed Miah Md. Masum Iqbal Md. Asif Karmakar Sumon Alam Md. Jahangir Khalid-Bin-Ferdaus Khandaker Md. Kabir Ahmad Humayan Rashid Md. Mamunur Talukder Mamunur Rashid Reza Md Abu 《Plasma Chemistry and Plasma Processing》2021,41(3):923-944
Plasma Chemistry and Plasma Processing - Plasma agriculture is an emerging field. In this report, we studied the effect of medium pressure (~?10 torr) low-frequency... 相似文献
29.
M. Idrish Miah 《Physics letters. A》2011,375(3):647-650
Multiphoton electronic-spin generation in semiconductors was investigated using differential transmission spectroscopy. The generation of the electronic spins in the semiconductor samples were achieved by multiphoton pumping with circularly polarized light beam and was probed by the spin-resolved transmission of the samples. The electronic spin-polarization of conduction band was estimated and was found to depend on the delay of the probe beam, temperature as well as on the multiphoton pumping energy. The temperature dependence showed a decrease of the spin-polarization with increasing temperature. The electronic spin-polarization was found to depolarize rapidly for multiphoton pumping energy larger than the energy gap of the split-off band to the conduction band. The results were compared with those obtained in one-photon pumping, which shows that an enhancement of the electronic spin-polarization was achieved in multiphoton pumping. The findings resulting from this investigation might have potential applications in opto-spintronics, where the generation of highly polarized electronic spins is required. 相似文献
30.
Musharraf SG Ali A Ali RA Yousuf S Rahman AU Choudhary MI 《Rapid communications in mass spectrometry : RCM》2011,25(1):104-114
Structural elucidation and gas‐phase fragmentation of ten withanolides (steroidal lactones) were studied using a positive ion electrospray ionization quadropole time‐of‐flight mass spectrometry (ESI‐QqTOF‐MS/MS) hybrid instrument. Withanolides form an important class of plant secondary metabolites, known to possess a variety of biological activities. Withanolides which possess hydroxyl groups at C‐4, C‐5, C‐17, C‐20, and C‐27, and an epoxy group at C‐5/C‐6, were evaluated to determine the characteristic fragments and their possible pathways. ESI‐QqTOF‐MS (positive ion mode) showed the presence of the protonated molecules [M + H]+. Low‐energy collision‐induced dissociation tandem mass spectrometric (CID‐MS/MS) analysis of the protonated molecule [M + H]+ indicated multiple losses of water and the removal of the C‐17‐substituted lactone moiety affording the [M + H–Lac]+ product ion as the predominant pathways. However, withanolides containing a hydroxyl group at C‐24 of the lactone moiety showed a different fragmentation pathway, which include the loss of steroidal part as a neutral molecule, with highly diagnostic ions at m/z 95 and 67 being generated from the cleavage of lactone moiety. Our results also determined the influence of the presence and positions of hydroxyl and epoxy groups on product ion formation and stability. Moreover, the knowledge of the fragmentation pattern was utilized in rapid identification of withanolides by the LC/MS/MS analysis of a Withania somnifera extract. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献