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81.
Dr. Natarajan Senthilkumar Dr. Kanniyappan Parthasarathy Dr. Parthasarathy Gandeepan Prof. Dr. Chien‐Hong Cheng 《化学:亚洲杂志》2013,8(9):2175-2181
An efficient method for the one‐pot synthesis of substituted phenanthridinone derivatives from N‐methoxybenzamides and aryltriethoxysilanes through rhodium‐catalyzed dual C? H bond activation and annulation reactions is described. A double‐cycle mechanism is proposed to account for this catalytic reaction. In addition, isotope‐labeling studies were performed to understand the intimate mechanism of the reaction. 相似文献
82.
Akshaya K. Nayak Venkatachari Parthasarathy Sisir K. Sarkar 《Infrared Physics & Technology》2001,42(6):535-540
Results of parametric studies on short CO2 laser pulse generation by laser induced dielectric breakdown in a plasma shutter cell are described. From the rise time of such short pulses obtained, threshold breakdown intensity (Ith) has been estimated for different gases. The technique is further extended to obtain 40 ns pulses on two-frequency emission from a single TEA CO2 laser. Pressure dependent studies of Ith are utilised to model the process of such laser induced plasma. 相似文献
83.
Loganathan Ramu Narendra Kuppan Keralapura Parthasarathy Ramesh Rattihalli Chandramani Daivagna Ramananda 《Magnetic resonance in chemistry : MRC》2019,57(8):499-505
35Cl NQR frequency and spin lattice relaxation time in 3,4-dichloronitrobenzene have been measured as a function of temperature and pressure. Two NQR signals were observed in the temperature range 77 to 300 K and pressure up to 5.1 kbar at 300 K. The contributions to the relaxation from the torsional motion of the molecule and reorientational motion of the nitro group have been analyzed on the basis of the Woessner and Gutowsky model. The temperature dependence of the average torsional lifetimes of the molecules, transition probabilities, and the activation energy for the reorientation of the nitro group was estimated. The pressure dependence of the NQR frequency in 3,4-Dichloronitrobenzene shows a nonlinear increase in NQR frequency with increase in pressure, indicating increased contribution from the static effects at higher pressures. A thermodynamic analysis of the data was carried out to determine the constant-volume temperature coefficients of the NQR frequency. The spin–lattice relaxation was found to be weakly dependent on pressure. 相似文献
84.
Sudhakar Maddala Anirban Panua Dr. Parthasarathy Venkatakrishnan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(64):16013-16020
While intramolecular Scholl oxidative coupling between two arenes is common, successful C−C heterocoupling between thiophene and arene is scarce. The latter is due to the notorious reactivity of thiophene towards polymerization under oxidative conditions. This report systematically demonstrates how topological variation of electronics and reactivity in thiophene substrates can lead to efficient oxidative heterocoupling. Bis(biaryl)thiophenes having reactive α- and β-positions open are the choice of substrates. The cyclizing arene partners are so electronically tuned for thiophene's reactivity (at α- and β-) as to establish C−C bond oxidatively generating symmetrical as well as unsymmetrical diphenanthrothiophenes which are basic thiananographenes. Depending on the cyclizing-couple's electronics, either arene- or thiophene-centered oxidation initiates C−C heterocoupling. The potential utility of these simple thiananographenes is further unfurled by converting them to functional N−/C-graphene segments that are aza-corannulene precursor and tetrabenzospirobifluorene. Their bright emission and extended electrochemical stability are remarkable that may be potentially important and applicable. 相似文献
85.
Suhanya Parthasarathy Surash Ramanathan Sabariah Ismail Mohd Ilham Adenan Sharif Mahsufi Mansor Vikneswaran Murugaiyah 《Analytical and bioanalytical chemistry》2010,397(5):2023-2030
A new solid phase extraction method for rapid high performance liquid chromatography–UV determination of mitragynine in plasma
has been developed. Optimal separation was achieved with an isocratic mobile phase consisting of acetonitrile–ammonium acetate
buffer, 50 mM at pH 5.0 (50:50, v/v). The method had limits of detection and quantification of 0.025 and 0.050 μg/mL, respectively.
The method was accurate and precise for the quantitative analysis of mitragynine in human and rat plasma with within-day and
between-day accuracies between 84.0 and 109.6%, and their precision values were between 1.7 and 16.8%. Additional advantages
over known methods are related to the solid phase extraction technique for sample preparation which yields a clean chromatogram,
a short total analysis time, requires a smaller amount of plasma samples and has good assay sensitivity for bioanalytical
application. The method was successfully applied in pharmacokinetic and stability studies of mitragynine. In the present study,
mitragynine was found to be fairly stable during storage and sample preparation. The present study showed for the first time
the detailed pharmacokinetic profiles of mitragynine. Following intravenous administration, mitragynine demonstrated a biphasic
elimination from plasma. Oral absorption of the drug was slow, prolonged and was incomplete, with a calculated absolute oral
bioavailability value of 3.03%. The variations observed in previous pharmacokinetic studies after oral administration of mitragynine
could be attributed to its poor bioavailability rather than to the differences in assay method, metabolic saturation or mitragynine
dose. 相似文献
86.
87.
Coherent continuation π
2 of a representation π
1 of a semisimple Lie algebra arises by tensoring π
1 with a finite dimensional representation F and projecting it to the eigenspace of a particular infinitesimal character. Some
relations exist between the spaces of harmonic spinors (involving Kostant’s cubic Dirac operator and the usual Dirac operator)
with coefficients in the three modules. For the usual Dirac operator we illustrate with the example of cohomological representations
by using their construction as generalized Enright-Varadarajan modules. In [9] we considered only discrete series, which arises
as generalized Enright-Varadarajan modules in the particular case when the parabolic subalgebra is a Borel subalgebra. 相似文献
88.
Junctions between lipid membranes make possible cell-free explorations of physical mechanisms that can contribute to protein and lipid organization at a variety of biophysical interfaces. Recent studies of mobile antibodies sandwiched between lipid bilayer membranes have shown that strong intermembrane adhesion and protein mobility alone are sufficient to drive inert proteins into micron-scale patterns of dense and sparse zones. Though the length scale of these patterns was suspected to be related to membrane rigidity, a quantitative understanding has so far been unavailable. We introduce data showing radially structured protein patterns that also demonstrate micron-scale organization. We then provide a simple model that relates the spectrum of membrane fluctuations to the observed protein distributions; in brief, only membrane modes that are slow enough to couple to the protein mobility drive intermembrane protein patterns. 相似文献
89.
90.