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361.
A. J. Varghese 《Photochemistry and photobiology》1974,20(5):461-464
Abstract —Sulfhydryl compounds such as cysteine and glutathione enhance the photochemical reactivity of 5-bromouracil irradiated in aqueous solution with ultraviolet light (Λ > 240 nm). Production of uracil and addition of the sulfhydryl compound to the 5-bromouracil residue are the major photoreactions. 相似文献
362.
Excision of cytosine-thymine adduct from the DNA of ultraviolet-irradiated Micrococcus radiodurans 总被引:2,自引:0,他引:2
Abstract— 6-4‘-[pyrimidin-2’-one]-thymine (PO-T), a deamination product of a cytosine–thymine adduct accounted for about 17 per cent of the total detectable thymine-derived photoproducts in u.v.-irradiated Micrococcus radiodurans. On incubation of the irradiated cells, oligonucleotides containing the photoproducts were released into the medium. After various periods of incubation the different photoproducts were isolated both from the cells and from the medium. Analysis of these different photoproducts showed that during the excision process the ratio of PO–T to total thymine-derived products remained constant both in the cells and in the medium. This shows that the precursor to PO–T is excised at the same rate as the other thymine-derived photoproducts by the dark repair mechanisms exhibited by this radiation-resistant organism. 相似文献
363.
ABSTRACTThe rapid development of consumer electronics and portable devices imposes a great demand for energy efficient information display systems. Among the information display devices, liquid crystal display (LCD) devices stands in the front. The fabrication of energy-efficient LCD systems demands new material and techniques. In this work, the conventional polyimide alignment layer of twisted nematic liquid crystal device (TNLCD) was replaced with ferroelectric polymer nanoparticle doped alignment layer. Morphology of the alignment layer was analysed using field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The ferroelectric nature of the polymer alignment layer was studied using dynamic contact electrostatic force microscopy (DC-EFM). TNLCD cells are fabricated with this modified alignment layer and the switching characteristics are compared with the conventional TNLCD devices. The TNLCD with modified alignment layer has shown a reduction of 50% in threshold (Vthr) and 47% reduction in saturation voltage (Vsat). 相似文献
364.
Jonathan Block Varghese Mathai Shmuel Weinberger 《Proceedings of the American Mathematical Society》1997,125(12):3757-3762
We give short proofs of the Gromov-Shubin theorem on the homotopy invariance of the Novikov-Shubin invariants and of the Dodziuk theorem on the homotopy invariance of the Betti numbers of the universal covering of a closed manifold in this paper. We show that the homotopy invariance of these invariants is no more difficult to prove than the homotopy invariance of ordinary homology theory.
365.
T. Varghese K. M. Balakrishna 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,57(1):9-11
The electron momentum distribution and Compton profiles of the rare earth
element Eu was measured using HPGe photon detector. The target atoms were
excited by means of 59.54 keV gamma rays from Am-241 radioactive source of
strength 300 mCi. Elemental foil of uniform aerial density, and purity
better than 99.9% was used as target. The data were recorded and analyzed
using a 4 K multichannel analyzer. These data duly corrected for instrumental
resolution effects, sample absorption, energy dependence of the differential
Compton cross-section and double scattering, and compared with theoretical
renormalized free atom (RFA) values. 相似文献
366.
Data reduction is an important issue in the field of data mining. The goal of data reduction techniques is to extract a subset of data from a massive dataset while maintaining the properties and characteristics of the original data in the reduced set. This allows an otherwise difficult or impossible data mining task to be carried out efficiently and effectively. This paper describes a new method for selecting a subset of data that closely represents the original data in terms of its joint and univariate distributions. A pair of distance criteria, motivated by the χ2-statistic, are used for measuring the goodness-of-fit between the distributions of the reduced and full datasets. Under these criteria, the data reduction problem can be formulated as a bi-objective quadratic program. A genetic algorithm technique is used in the search/optimization process. Experiments conducted on several real-world data sets demonstrate the effectiveness of the proposed method. 相似文献
367.
Bhavana Purushothaman Babu Varghese Puttaiah Bhyrappa 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(3):252-253
In the title complex, [Zn(C36H20N4S4)], the ZnII ion occupies a special position on an inversion centre with four-coordinate geometry. The porphyrin ring shows a wave-like conformation, with the closest interporphyrin plane separation being 3.60 (6) Å. The two disordered thienyl groups are inclined with respect to the porphyrin plane at angles of 70 (4) and 67 (2)°. 相似文献
368.
Vinayakrishnan Rajan Babu Varghese Ton G. van Leeuwen Wiendelt Steenbergen 《Optics Communications》2008,281(6):1755-1760
We report on the dependence of the decorrelation time on the spatial intensity correlation of speckles generated in the far-field by back-scattered photons from turbid media. The effects contribute to an explanation of an earlier observation that the average Doppler width of the power spectrum of detector current fluctuations depends on the size of the illuminating laser beam. The space-time correlation of the speckles generated by a particle suspension illuminated by a collimated laser beam is analyzed from serial images taken by a high speed camera. It was found that larger spatial correlation distances, associated with large speckles, exhibit a slower temporal decorrelation. 相似文献
369.
A molecular salt with formula [BmIm]3[PMo12O40]3? has been prepared using room temperature ionic liquid and phosphomolybdic acid. The material is characterized by single-crystal X-ray diffraction. The compound crystallizes in orthorhombic system with space group Pca21. It is also characterized by CHN analysis, 31P MAS NMR, UV–vis DRS and near-IR methods. Thermal stability of the compound is investigated by TGA, IR and PXRD methods. Near-IR shows the loss of water of crystallization by the Keggin ions of phosphomolybdic acid bonded with ionic liquid. 相似文献
370.
Hema Tresa Varghese C. Yohannan Panicker V.S. Madhavan Samuel Mathew Jarmila Vinsova Christian Van Alsenoy 《Journal of Raman spectroscopy : JRS》2009,40(9):1211-1223
FT‐IR and FT‐Raman spectra of 4‐chloro‐2‐(4‐bromophenylcarbamoyl)phenyl acetate were recorded and analyzed. The vibrational wavenumbers and corresponding vibrational assignments were examined theoretically using the Gaussian03 set of quantum chemistry codes. The red shift of the NH stretching wavenumber in the infrared (IR) spectrum from the computed wavenumber indicates the weakening of the NH bond resulting in proton transfer to the neighbouring oxygen atom. The simultaneous IR and Raman activations of the CO stretching mode give the charge transfer interaction through a π‐conjugated path. Optimized geometrical parameters of the title compound are in agreement with similar reported structures. From the optimized structure, it is clear that the hydrogen bonding decreases the double bond character of CO bond and increases the double bond character of the C N bonds. The first hyperpolarizability, predicted infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non‐linear optics. The assignments of the normal modes are done by potential energy distribution (PED) calculations. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献