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排序方式: 共有406条查询结果,搜索用时 31 毫秒
311.
A well-sustained multistep synthetic protocol has been designed for the PEG-functionalized aromatic acid amide to generate a molecular library of 2-alkylthio bis-benzimidazoles. An attempted synthesis of benzimidazole-2-thiol in dichloromethane has led to S-chloromethyl methyl sulfides, mimicking bacterial enzymatic systems. Regioselective S-alkylation was brought about under controlled conditions using a mild base at room temperature. The polymer-free compounds, 2-sulfanylated bisbenzimidazoles, were obtained in high yields and high purities. Chemical shift changes in proton and carbon NMR have been employed to monitor the progress of the reaction steps and to prove the site of S-alkylation, respectively. 相似文献
312.
Dibyendu Mahato Lalita Sharma Rajesh Srivastava 《International journal of quantum chemistry》2022,122(1):e26815
A study is presented on the elastic scattering of electrons from Nq+ (q = 1–3), Na+, Arq+ (q = 1–3, 7–8), Xeq+ (q = 2–6, 8) to understand the available experimental differential cross section results. A model potential approach has been utilized to describe the scattering process. The model potential includes the static, exchange, polarization and absorption potentials. The static potentialis obtained through the charge density calculated by obtaining ionic wave functions using multi-configuration Dirac-Fock (MCDF) approximation. Thereafter, the static potential is added to the suitable exchange, polarisation and absorption potentials to construct the spherically averaged complex optical potential. Using the obtained potential in the Dirac equations,these are solved with the partial wave phase shift analysis method and the differential cross sections are calculated. Results for different ions exhibit prominent interference structures in the energy versus cross section curves and show good agreement on comparison with the experimental results available in the selected energy ranges. 相似文献
313.
Mishra T Hait J Aman N Gunjan M Mahato B Jana RK 《Journal of colloid and interface science》2008,327(2):377-383
Spherical silica and zirconia mixed titania and pure titania samples were prepared in presence of cetyltrimethylammonium bromide (CTAB) through controlled hydrolysis of corresponding metal alcoxides. Effect of surfactant amount and calcinations temperature on morphology, surface area and photocatalytic activity is studied using PXRD, SEM, FTIR, Solid state UV-vis spectroscopy and BET surface area. It is well observed that in presence of 2 mol% CTAB, uniform sized spherical oxide particles can be synthesized. However, increasing or decreasing the surfactant amount does not favor the spherical particle formation. Material synthesis in presence of CTAB not only helps in the spherical particle formation but also increases the surface area and visible light absorption. Studies on photocatalytic lead removal with respect to calcination temperature indicate that the calcination at 500 degrees C is most suitable for the best photocatalytic activity. Mixing of zirconia and silica helps in anatase phase stabilization even at 900 degrees C calcination. Accordingly low decrease in surface area even at 900 degrees C calcination is observed. Due to the phase stabilization and higher surface area binary oxide materials showed comparatively better photocatalytic activity even after calcination at 900 degrees C. So it can be concluded that present synthesis approach can produce uniform sized spherical binary oxide materials with better photocatalytic activity in visible light. 相似文献
314.
Sharma GV Manohar V Dutta SK Subash V Kunwar AC 《The Journal of organic chemistry》2008,73(10):3689-3698
Hybrid peptides are prepared from a C-linked carbo-beta-amino acid ester (R-beta-Caa) and an alpha-aminoxy acid (R-Ama) derived from S-lactic acid. Extensive NMR (in CDCl 3 solution), CD, and MD studies on the tetra- and hexapeptides led to identification of robust 12/10-mixed helices. The dipeptide repeat having an R-beta-Caa and an R-Ama thus provides a "new motif" to realize a 12/10-mixed helix, for the first time, in oligomers containing R-Ama. To understand the impact of side chains in the mixed helix formation, R-beta-Caa/Ama (with no substitution in Ama) and S-beta-hAla/R-Ama oligomers were investigated. NMR studies revealed the existence of 12/10-helices in these hybrid peptides, and the side chains of monomers were found to have a profound influence on their stabilities. These observations imply that the propensity of beta-amino acid to prefer a mixed 12/10-helix governs the structural behavior in these peptides. The structural consequences of the lone-pair repulsion between nitrogen and oxygen atoms result in a new and interesting structural motif which behaves like "pseudo" beta (3),beta(2)-peptides in generating 12/10-mixed helices. 相似文献
315.
Ekar Satish U. Shekhar Ganga Khollam Yogesh B. Wani Poonam N. Jadkar Sandesh R. Naushad Mu Chaskar Manohar G. Jadhav Santosh S. Fadel Alaa Jadhav Vijaykumar V. Shendkar Janardhan H. Mane Rajaram S. 《Journal of Solid State Electrochemistry》2017,21(9):2713-2718
Journal of Solid State Electrochemistry - Nanorods (NRs) of TiO2 have biogenically been prepared, i.e., from the extract of Phellinus linteus mushroom. The presence of mixed anatase and... 相似文献
316.
317.
S. S. Rattan A. Ramaswami S. B. Manohar 《Journal of Radioanalytical and Nuclear Chemistry》1999,242(2):551-555
Fission product yield studies in the reaction of 73,4 and 84.2 MeV12C with209Bi have been carried out using gamma-ray spectrometry. The cross sections for the production of fission products have been
determined. The yield distribution of fission products is found to be symmetric and broad with FWHM around 25 mass units and
peak near mass 107.7 and 107.0. The average number of neutrons emitted per fission have been found to be around 5.5 at 73.4
MeV and 7.1 at 84.2 MeV, respectively. 相似文献
318.
The determination of defect depth and size using Pulsed Infrared Thermography is a critical problem. The problem of defect depth estimation has been previously studied using 1D heat conduction models. Unfortunately, 1D heat conduction based models are generally inadequate in predicting heat flow around defects. In this study, a novel approach based on virtual heat sources is proposed to model heat flow around defects accounting for 2D axisymmetric heat conduction. The proposed approach is used to quantitatively determine the defect depth and size. The validity of the model is established using experiments performed on a stainless steel plate specimen with flat bottom holes at different depths. 相似文献
319.
Manohar Radhakrishnan Malathy Palayam Ammar B. Altemimi Lakshminarayanan Karthik Gunasekaran Krishnasamy Francesco Cacciola Lakshmanan Govindan 《Molecules (Basel, Switzerland)》2022,27(4)
A 24 kDa leucine-rich protein from ion exchange fractions of Solanum trilobatum, which has anti-bacterial activity against both the Gram-negative Vibrio cholerae and Gram-positive Staphylococcus aureus bacteria has been purified. In this study, mass spectrometry analysis identified the leucine richness and found a luminal binding protein (LBP). Circular dichroism suggests that the protein was predominantly composed of α- helical contents of its secondary structure. Scanning electron microscopy visualized the characteristics and morphological and structural changes in LBP-treated bacterium. Further in vitro studies confirmed that mannose-, trehalose- and raffinose-treated LBP completely inhibited the hemagglutination ability towards rat red blood cells. Altogether, these studies suggest that LBP could bind to sugar moieties which are abundantly distributed on bacterial surface which are essential for maintaining the structural integrity of bacteria. Considering that Solanum triolbatum is a well-known medicinal and edible plant, in order to shed light on its ancient usage in this work, an efficient anti-microbial protein was isolated, characterized and its in vitro functional study against human pathogenic bacteria was evaluated. 相似文献
320.
Two mononuclear cobalt(III) complexes, namely [LCo(tmtp)(H2O)]ClO4?MeOH ( 1 ) (tmtp = tri(m‐tolyl)phosphine) and [LCo(PPh3)(H2O)]PF6 ( 2 ), have been prepared from a polydentate ligand, N,N′‐bis(3‐methoxysalicylidehydene)cyclohexane‐1,2‐diamine ( H 2 L ). Standard analytical techniques such as elemental analysis and UV–visible and Fourier transform infrared spectroscopies were used to characterize both complexes. The solid‐state molecular structures of both complexes were confirmed from single‐crystal X‐ray diffraction analysis. Structural analyses show that the Co(III) ion occupies the centre of a distorted octahedron in a complex cation: [LCo(tmtp)(H2O)]+ and [LCo(PPh3)(H2O)]+ for 1 and 2 , respectively. Phenoxazinone synthase activities of both complexes were screened. Kinetic studies and other experimental observations reveal that the reaction follows rate saturation kinetics and proceeds through the formation of a catalyst (complex)–substrate adduct. The turnover number (Kcat) of complex 2 is 54.07 h?1, exhibiting better catalytic activity compared to 1 (Kcat = 45.11 h?1). 相似文献