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161.
Shukla-Dave A Degaonkar M Roy R Murthy PK Murthy PS Raghunathan P Chatterjee RK 《Magnetic resonance imaging》1999,17(10):1437-1509
Metabolite mapping of human filarial parasite, Brugia malayi was carried out in vitro as well as in situ in host Mastomys coucha by 31P nuclear magnetic resonance (NMR) spectroscopy. Detection of parasites by visualizing contrast spots due to pathologic changes was observed by 1H magnetic resonance imaging (MRI). Major metabolites of adult B. malayi observed by 31P-NMR spectroscopy were of sugar phosphates (SP), phosphomonoesters (PME), glycerophosphoryl-ethanolamine (GPE), -choline (GPC), phosphoenolpyruvate (PEP), inorganic phosphate (Pi), nucleoside diphosphosugar and nucleotides-mono, -di and -tri phosphates. PEP and GPC were present in high concentration; PEP being the major energy reservoir and GPC the major phospholipid in this species of filaria. The 31P NMR spectra of testis of mastomys, showed seven major peaks of SP, PME, phosphocreatine (PCr), phosphodiesters (PDE), Pi, and nucleotides di- and tri-phosphates. The 31P-NMR spectra of testis of B. malayi infected animal also consisted of seven major peaks with significant decrease in the SP and PME peak showing changes in the carbohydrate and lipid metabolism of filaria infected testis. Thus, in vivo 31P MRS provided a non-invasive assessment of tissue bioenergetics and phospholipid metabolism. 相似文献
162.
We have incorporated the flexoelectric terms in developing one-dimensional models of E.H.D. instabilities in nematics both under D.C. and A.C. excitations. It is shown that, using this model, we can account for the following experimental observations, which could not be adequately explained by earlier models: (i) The observation of oblique rolls whose wave vector q makes an angle α with the undistorted director n 0, up to some frequency v 0 in the conduction regime; (ii) the oblique rolls found in the dielectric regime; and (iii) the ‘longitudinal’ E.H.D. instabilities in some systems with negative conductivity anisotropy. We also present some experimental observations under D.C. excitation. 相似文献
163.
The 1,3-dipolar cycloaddition reaction of tryarylideneacetyacetone derivatives with N-metalated azomethine ylides in the presence of titanocene dichloride and triethylamine has been investigated. This two-step synthetic sequence is very efficient and yielded the highly substituted pyrrolidines in good yields. The structure and stereochemistry of one of the products has been established by single-crystal x-ray structure and spectroscopic techniques. 相似文献
164.
Nieh MP Raghunathan VA Pabst G Harroun T Nagashima K Morales H Katsaras J Macdonald P 《Langmuir : the ACS journal of surfaces and colloids》2011,27(8):4838-4847
Bicellar model membranes composed of 1,2-dimyristoylphosphatidylcholine (DMPC) and 1,2-dihexanoylphosphatidylcholine (DHPC), with a DMPC/DHPC molar ratio of 5, and doped with the negatively charged lipid 1,2-dimyristoylphosphatidylglycerol (DMPG), at DMPG/DMPC molar ratios of 0.02 or 0.1, were examined using small angle neutron scattering (SANS), (31)P NMR, and (1)H pulsed field gradient (PFG) diffusion NMR with the goal of understanding temperature effects on the DHPC-dependent perforations in these self-assembled membrane mimetics. Over the temperature range studied via SANS (300-330 K), these bicellar lipid mixtures exhibited a well-ordered lamellar phase. The interlamellar spacing d increased with increasing temperature, in direct contrast to the decrease in d observed upon increasing temperature with otherwise identical lipid mixtures lacking DHPC. (31)P NMR measurements on magnetically aligned bicellar mixtures of identical composition indicated a progressive migration of DHPC from regions of high curvature into planar regions with increasing temperature, and in accord with the "mixed bicelle model" (Triba, M. N.; Warschawski, D. E.; Devaux, P. E. Biophys. J.2005, 88, 1887-1901). Parallel PFG diffusion NMR measurements of transbilayer water diffusion, where the observed diffusion is dependent on the fractional surface area of lamellar perforations, showed that transbilayer water diffusion decreased with increasing temperature. A model is proposed consistent with the SANS, (31)P NMR, and PFG diffusion NMR data, wherein increasing temperature drives the progressive migration of DHPC out of high-curvature regions, consequently decreasing the fractional volume of lamellar perforations, so that water occupying these perforations redistributes into the interlamellar volume, thereby increasing the interlamellar spacing. 相似文献
165.
R. Krishna D. Velmurugan S. Shanmuga Sundara Raj H.‐K. Fun M. S. Sundaram R. Raghunathan 《Crystal Research and Technology》2001,36(11):1289-1294
The title compound (6,6‐dimethyl‐cis‐6H,6aH,7H,12bH,13H‐bis[1]benzopyrano[4,3‐b:4',3'‐d]pyran‐13‐one) crystallizes in monoclinic space group P21 /c with Z = 4. The unit cell dimensions are a = 8.6231(2) Å, b =10.0260(2) Å, c = 19.8376(2) Å, and β = 102.1(1)°, V = 1674.51(5) Å3 , Dcal = 1.326 Mg/m3. The coumarin moiety is in the planar conformation, the dioxadecalin moiety is cis fused and within the dioxadecalin moiety both the rings are in half cahir/sofa conformations. The structure has many C‐H … O type interactions. 相似文献
166.
S. Thinagar D. Velmurugan A. Amalraj R. Raghunathan 《Crystal Research and Technology》2000,35(8):979-986
3‐Phenyl‐chroman‐4‐one is the basic unit of isoflavonoids which are found in the plants of the sub‐family papilionoidae of Leguminosae. They are known to possess antifungal and antibacterial properties. Crystal data of the title compound : Monoclinic, space group P21/c, a = 14.021(3), b = 18.682(4), c = 11.362(2) Å, β = 95.75(3)°, R = 0.066. The two phenyl rings directly attached to the pyrrolidine ring are nearly perpendicular to it. The dihydropyrone moiety adopts a half‐chair conformation while the cyclohexane ring attached to the pyrrolidine ring adopts a chair conformation. The best plane passing through the chroman‐4‐one moiety makes a dihedral angle of 82.2(3)° with the pyrrolidine ring. The molecule is stabilized by one intra‐ and two intermolecular C‐H...O hydrogen bonds. 相似文献