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41.
Dr. Sinan Wang Dr. David E. Korenchan Paola M. Perez Dr. Céline Taglang Dr. Thomas R. Hayes Dr. Renuka Sriram Dr. Robert Bok Andrew S. Hong Yunkou Wu Henry Li Prof. Zhen Wang Prof. John Kurhanewicz Prof. David M. Wilson Prof. Robert R. Flavell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(51):11842-11846
Alterations in Zn2+ concentration are seen in normal tissues and in disease states, and for this reason imaging of Zn2+ is an area of active investigation. Herein, enriched [1-13C]cysteine and [1-13C2]iminodiacetic acid were developed as Zn2+-specific imaging probes using hyperpolarized 13C magnetic resonance spectroscopy. [1-13C]cysteine was used to accurately quantify Zn2+ in complex biological mixtures. These sensors can be employed to detect Zn2+ via imaging mechanisms including changes in 13C chemical shift, resonance linewidth, or T1. 相似文献
42.
A dual field grating has been introduced for use in Talbot interferometry. We report here results of an experimental investigation on setting sensitivity when using these gratings for testing. 相似文献
43.
Srinivas Nanduri Vijay Kumar Nyavanandi Mahendar Velisoju Sriram Rajagopal R Rajagopalan 《Tetrahedron letters》2004,45(25):4883-4886
Andrographolide 1, the major constituent of the Indian medicinal plant Andrographis paniculata (Acanthaceae) was converted into the key intermediate 4 by selective oxidative degradation of the C-12,13 olefin bond. The aldehyde functional group present in 4 has been utilized for synthesizing a number of structurally diverse labdane diterpenes. Synthesis and in vitro cytotoxic activity results of the compounds prepared are discussed. 相似文献
44.
Chakravarty PK Tyagarajan S Shih TL Salva S Snedden C Wyvratt MJ Fisher MH Meinke PT 《Organic letters》2002,4(8):1291-1294
An efficient synthesis of the truncated 3"-aldehyde (3) from nodulisporic acid A (1) under mild conditions is described. Further oxidation of 3 to 3"-carboxylic acid (4) and its subsequent oxidative degradation produced 1"-aldehyde (5). These new derivatives are versatile intermediates for the preparation of new, side chain modified derivatives of nodulisporic acid A. [reaction: see text] 相似文献
45.
46.
Numerical simulation of nonlinear waves to reproduce the laboratory measurements has been a topic of great interest in the recent past. The results reported in the literature are mainly focused on qualitative comparison or on the relative errors between the numerical simulation and measurements in laboratory and hence lack in revealing the existence of phase shift in nonlinear wave simulation. In this paper, the simulation of nonlinear waves in mixed Eulerian and Lagrangian framework using finite element method (FEM) is investigated by applying two different velocity calculation methods viz, cubic spline and least squares (LS). The simulated wave surface elevation has been compared with the experimental measurements. The coherence analysis has been carried out using the wavelet transformation, which gives a better understanding between the numerical and the experimental results with respect to the time–frequency space, compared with the conventional Fourier transformation. It is observed that the application of cubic spline approach leads to a higher phase difference for steeper waves. The present study has shown that the phase difference exists at the higher modes rather than at the primary period. For waves with steepness (wave height/wave length) higher than 0.04, LS approach is found to be effective in capturing the higher‐order frequency components in the event of nonlinearity. In addition, the comparison of numerical simulations with that from PIV measurements for the tests with solitary waves is also reported. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
47.
Sriram Ramaswamy 《Phase Transitions》2013,86(1-4):575-588
This is a brief review of the theory of topological defects in quasicrystals, within a densitywave picture. 相似文献
48.
Swafford LA Weigand LA Bowers MJ McBride JR Rapaport JL Watt TL Dixit SK Feldman LC Rosenthal SJ 《Journal of the American Chemical Society》2006,128(37):12299-12306
Alloy nanocrystals provide an additional degree of freedom in selecting desirable properties for nanoscale engineering because their physical and optical properties depend on both size and composition. We report the pyrolytic synthesis of homogeneously alloyed CdS(x)Se(1-x) nanocrystals in all proportions. The nanocrystals are characterized using UV-visible absorption spectroscopy, transmission electron microscopy, X-ray diffractrometry, and Rutherford backscattering spectrometry to determine precisely structure, size, and composition. The dependence of band gap on nanocrystal size and composition is elucidated, yielding a bowing constant of 0.29, in agreement with bulk values. In addition, the morphology of the resultant nanocrystals can be altered by changing the reaction conditions, generating structures ranging from homogeneous, spherical nanocrystals to one-dimensional gradient nanorods. 相似文献
49.
Sivasubramanian Muthusaravanan Subbu Perumal Perumal Yogeeswari Dharmarajan Sriram 《Tetrahedron letters》2010,51(49):6439-6443
The domino reactions of pyridine/isoquinoline, bromoacetonitrile/ethyl bromoacetate and a series of β-nitrostyrenes in the presence of triethylamine afforded novel tri-/disubstituted indolizines and pyrrolo[2,1-a]isoquinolines regioselectively, presumably via substitution-dipole generation-1,3-dipolar cycloaddition-elimination and/or aromatisation sequence. In vitro screening of all the seventeen compounds synthesized against Mycobacterium tuberculosis H37Rv discloses that ethyl 2-(4-fluorophenyl)pyrrolo[2,1-a]isoquinoline-3-carboxylate displays maximum potency with minimum inhibitory concentration (MIC) of 1.0 μM, being 7.6 and 4.7 times more potent than the standard first line TB drugs, ethambutol and ciprofloxacin, respectively. 相似文献
50.
Epibatidine (EPB) (1), an alkaloid isolated from the skin of the Ecuadorian poison frog, Epipedobates tricolor has attracted attention because of its exceptionally powerful analgesic properties: several hundred times greater than those of morphine, and the fact that it acts at nicotine rather than opiate receptors. Although the substance is toxic, it does serve as a lead compound in the development of drugs for pain relief as well as treatment of disorders whose pathogenesis involves nicotinic receptors. In this article, isolation, synthetic methods, effect on neuronal and neuromuscular nicotinic receptors, therapeutic potential, toxicity, nicotinic pharmacophore structural modifications related issues of 1 are discussed. 相似文献