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41.
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Rajiv Dahiya Monika Maheshwari Anil Kumar 《Monatshefte für Chemie / Chemical Monthly》2009,140(1):121-127
Abstract The present investigation deals with the synthesis of a N-methylated cyclotetrapeptide, hirsutide (2), by coupling of the dipeptide units Boc-l-phenylalanyl-l-N-methylphenylalanine-OH and l-valyl-l-N-methylphenylalanine-OMe followed by cyclization of the linear tetrapeptide fragment. The chemical structure was established
on the basis of analytical as well as spectroscopic data. The newly synthesized cyclic peptide was subjected to pharmacological
screening and found to be highly potent against the gram-negative bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae at 6 μg cm−3. In addition, potent antihelmintic activity against the earthworms Megascoplex konkanensis and Pontoscotex corethruses at 1 and 2 mg cm−3, and potent cytotoxic activity against Dalton’s lymphoma ascites and Ehrlich’s ascites carcinoma cell lines with IC50 values of 14 and 22 μM were also observed. Studies revealed that the pentafluorophenyl ester method employing a catalytic
amount of N-methylmorpholine proved to be better for cyclization of the linear tetrapeptide unit.
Graphical abstract
相似文献
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The rotational states of adsorbed polar molecule in the presence of static electric and laser field are investigated. In this study, we have taken two types of polar molecules, namely, one with large dipole moment and moderate rotational constant (LiCl), and the other with moderate dipole moment and large rotational constant (HBr). The adsorbed molecule is considered as rigid rotor in finite conical potential well. The eigenvalues are calculated by numerically solving the Schrödinger equation. We have shown that various properties of rotational states of the molecules are significantly influenced by the static electric field, laser field, conical potential well height and the hindrance angle. Also the use of two different polar molecules for the investigation is justified by the variation in various properties due to change in molecule. 相似文献
45.
We study chiral symmetry structure at finite density and temperature in the presence of external magnetic field and gravity,
a situation relevant in the early Universe and in the core of compact stars. We then investigate the dynamical evolution of
phase transition in the expanding early Universe and possible formation of quark nuggets and their survival. 相似文献
46.
Mukhamed L. Keshtov Igor O. Konstantinov Alexei R. Khokhlov Ilya E. Ostapov Vladimir G. Alekseev Zhiyuan Xie Hemraj Dahiya Ganesh D. Sharma 《Journal of polymer science. Part A, Polymer chemistry》2022,60(14):2086-2099
We have designed and synthesized two wide bandgap new donor-acceptor (D-A) copolymers consisting of the same alkylthiazole-substituted benzo[1,2-b;4,5-b′]dithiophene (BDTTz) donor unit and but different acceptor units, i.e., thiazolo[5,4-d]thiazole (TTZ) ( P122 ) and 1,3,-4 thiadiazole (TDz) ( P123 ) and investigated their optical and electrochemical properties. We have employed these copolymers as donor and fullerene (PC 71 BM) and narrow bandgap non-fullerene (Y6) as acceptor, to fabricate binary and ternary bulk heterojunction polymer solar cells (PSCs). The overall power conversion efficiency (PCE) of optimized binary bulk heterojunction PSCs based on P122 :Y6 and P123 :Y6 is 12.60% and 13.16%, respectively. The higher PCE for PSCs based on P123 than P122 counterparts may be associated with the broader absorption profile of the P123 and more charge carrier mobilities than that for the P122 active layer. With the incorporation of small amount of PC71BM into either P122 :Y6 or P123 :Y6 binary blend, the corresponding ternary PSCs showed an overall PCE of 14.89% and 15.52%, respectively, which is higher than the binary counterparts using either Y6 or PC71BM as acceptor. Incorporating the PC71BM in the binary host blend increases the absorption in the 300–500 nm wavelength region, generating more excitons in the active ternary layer and helping to dissociate the excitons into free charge carriers more effectively. The more appropriate nanoscale phase separation in the active ternary layer than the binary counterpart may be one of the reasons for higher PCE. 相似文献
47.
The oscillatory nature of two equations (r(t) y′(t))′ + p1(t)y(t) = f(t), (r(t) y′(t))′ + p2(t) y(t ? τ(t))= 0, is compared when positive functions p1 and p2 are not “too close” or “too far apart.” Then the main theorem states that if h(t) is eventually negative and a twice continuously differentiable function which satisfies (r(t) h′(t))′ + p1(t) h(t) ? 0, then this inequality is necessary and sufficient for every bounded solution of (r(t) y′(t))′ + p2(t) y(t ? τ(t)) = 0 to be nonoscillatory. 相似文献
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The results of the alteration in the dispersion characteristic of a plasma under externally applied strong radio-frequency electric field are presented. The ion acoustic soliton slows down due to the variation in the dispersion characteristic of the plasma. 相似文献
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Dahiya R.P. Mishra S.K. Veefkind A. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1993,21(3):346-348
In a streamer-dominated pulsed corona the energetic electrons can interact with the background molecules and produce O, OH, and HO2 radicals. Reactions involving these radicals are studied to analyze their effect on the removal of acidic pollutants NO, NO2 , and SO2 from flue gases. For the NO removal the reactions with O and HO2 play a dominant role, whereas the OH radical is primarily responsible for the SO2 and NO2 removal 相似文献
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