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41.
Chemical investigation of polar fractions of the methanol extract of the fruits of Diploclisia glaucescens of the family Menispermaceae furnished two new phenyl glycosides, 4-(2-nitroethyl)phenyl-beta-D-xylopyranosyl-(l approximately 6)-beta-D-glucopyranoside, and 4-cyanophenyl-beta-D-xylopyranosyl-(l approximately 6)-beta-D-glucopyranoside.  相似文献   
42.
The high spin states in N=80 139Pr have been investigated by in-beam γ-spectroscopic techniques following the reaction 130Te (14N, 5n) reaction at E=75 MeV, using a gamma detector array, consisting of seven 23% compton-suppressed high purity germanium detectors and a multiplicity ball of fourteen bismuth germanate elements. Based on γ-γ coincidence data, the level scheme of 139Pr has been considerably extended up to 7.2 MeV excitation. Tentative spin-parity assignments are done for the newly proposed levels on the basis of the DCO ratios corresponding to strong gates and the available information from the earlier light ion experiments.  相似文献   
43.
We have identified some important and worthwhile physics opportunities with a possible neutrino detector located in India. Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other neutrino detectors already in operation.  相似文献   
44.
Sodium dialkyl phosphite reacts with non-activated alkyl halide in the presence of crown ether to give dialkyl alkyl phosphonate in moderate yield. Little or no reaction takes place in the absence of crown ether under the same conditions. In all cases, crown ether was present in catalytic amts. indicating that it behaves as a phase transfer catalyst between solid and liquid phases. The influences of structures of crown ethers, alkyl halides, dialkyl phosphites and the nature of solvent on the P-alkylation of sodium dialkyl phosphite have been investigated.  相似文献   
45.
The proanthocyanidins of the leaves of 16 taxa of the Rhododendron genus (Ericaceae) [Rhododendron ‘Catawbiense Grandiflorum’, Rhododendron ‘Cunningham's White’, Rhododendron smirnowii Trautv., Rhododendron calophytum Franch., Rhododendron dichroanthum ssp. scyphocalyx (Balf. f. & Forrest ) Cowan, Rhododendron micranthum Turcz., Rhododendron praevernum Hutch., Rhododendron ungernii Trautv., Rhododendron kaempferi Planch., Rhododendron degronianum ssp. heptamerum var. hondoense ( Nakai ) H. Hara, Rhododendron fortunei Lindl., Rhododendron ponticum L., Rhododendron galactinum Balf. f. ex Tagg., Rhododendron oreotrephes W. W. Sm., Rhododendron brachycarpum ssp. brachycarpum D. Don ex G. Don, and Rhododendron insigne Hemsl. & E. H. Wilson ] were investigated qualitatively by liquid chromatography–mass spectrometry in series. Twenty‐nine dimeric proanthocyanidins based on (epi)catechin and (epi)gallocatechin were detected and characterized on the basis of their unique fragmentation pattern in the negative ion mode tandem mass spectrometry spectra. All of them were extracted for the first time from these sources, and ten of them were not reported previously in nature. The position of the galloyl residue was assigned on the basis of the retro‐Diels–Alder fragmentation and the dehydrated retro‐Diels–Alder fragmentation; it resulted from the loss of gallic acid as a neutral loss in the negative ion mode. Furthermore, four caffeoylquinic acids, six p‐coumaroylquinic acids, epigallocatechin, gallocatechin, catechin, epicatechin, epigallocatechin gallate, catechin gallate, epicatechin gallate, gallocatechin gallate, two quercetin‐O‐hexosides, quercetin‐O‐galloyl‐hexoside, quercetin‐O‐pentoside, quercetin‐O‐rhamnoside, quercetin‐O‐pentoside‐O‐hexoside, quercetin‐O‐rhamnoside‐O‐hexoside, quercetin‐O‐feruloyl‐hexoside, quercetin‐O‐(p‐hydroxy)benzoyl‐hexoside, taxifolin‐O‐pentoside, myricetin‐O‐rhamnoside, two myricetin‐O‐pentosides, three myricetin‐O‐hexosides, and two myricetin‐O‐galloyl‐hexosides were detected and shown to possess characteristic tandem mass spectrometry spectra and were tentatively assigned on the basis of their retention time. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
46.
Chronic liver inflammation has become a major global health concern. In the absence of clinical surrogate markers to diagnose inflammatory liver disease, the intervention with effective drugs in modern medicine tends to be late. In Sri Lanka, traditional medical practitioners prescribe herbal preparations from Osbeckia octandra for the prevention and treatment of liver disorders. To test the efficacy of such treatments, we have administered thioacetamide (TAA) to male Wistar rats to induce chronic liver damage (disease control; DC) and examined how various leaf extracts: crude leaf suspension (CLS), boiled leaf extract (BLE), sonicated leaf extract (SLE), methanol leaf extract (MLE) and hexane leaf extract (HLE) of O. octandra ameliorate TAA-induced liver disease. The CLS, BLE and SLE treatments in cirrhotic rats significantly attenuated disease-related changes, such as liver weight and hepato-enzymes. The mRNA levels of Tnf-α were significantly decreased by 3.6, 10 and 3.9 times in CLS, BLE and SLE compared to DC. The same treatments resulted in significantly lower (19.5, 4.2 and 2.4 times) α-Sma levels compared to DC. In addition, Tgf-β1 and Vegf-R2 mRNA expressions were significantly lower with the treatments. Moreover, BLE expressed a strong anti-angiogenic effect. We conclude that CLS, BLE and SLE from O. octandra have potent hepatic anti-fibrotic effects in TAA-induced liver cirrhosis.  相似文献   
47.
SN Bhatia 《Pramana》2002,58(5-6):817-825
We have measured the in-plane resistivity of Bi2Sr2CaCu2O8+δ and Tl2Ba2 CaCu2O8+δ single crystals in the temperature range 70–300 K. The thermodynamic fluctuations in the conductivity of both the samples start around ∼ 125 K. We find the Lawrence and Doniach [1] model to be inadequate to describe the fluctuation conductivity in these materials. The modification suggested by Ramallo et al [4] where by the conductivity is enhanced due to the presence of two superconducting layers in each unit cell is also not adequate. We suggest the fluctuation conductivity to be reduced due to the reduction in the density of states (DOS) of the quasiparticles which results due to the formation of Cooper pairs at the onset of the fluctuations. The data agrees with the theory proposed by Dorin et al [5] which takes into account this reduction in DOS.  相似文献   
48.
Clover detector has been used as a Compton polarimeter to measure the linear polarization of γ-rays produced in heavy ion fusion reaction. The polarization sensitivity of the clover detector has been measured over γ-ray energies ranging from 386 to 1368 ke V. The E1 multipolarity of the 1117 keV transition in 99Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at 3710 keV in 99Rh.  相似文献   
49.
Spinning composite polymer fibres by means of electric fields has been investigated for well over a century. These spun fibres have been explored across many areas of research, spanning the physical to the life sciences; however, electrospinning has the hazardous nature of the high voltage at the spinning needle. We demonstrate here a competing direct fibre to scaffold preparation method, completely determined by an applied pressure. Our technique reported here removes the hazardous high‐voltage element from the fibre/scaffold formation technique and has the ability to form uniaxial fibres and scaffolds comparable to those fabricated by electrospinning. We refer to this fibre generation approach as “pressure‐assisted spinning (PAS)”, which will have a tremendous impact in a range of applications, spanning the physical through to the life sciences. PAS joins the techniques for fibre to scaffold generation with a view to significantly and globally contributing to the micro‐ and nanosciences.

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50.
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