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111.
Exploiting the diene nature of 6-[1-aza-2-(dimethylamino)prop-l-enyl]-1,3-dimethyluracil (2), novel 5-aryl-pyrido[2,3-d]pyrimidines (5a–h) have been synthesized. The reaction proceeds through a triene intermediate whose structure has been conclusively established by single crystal X-ray analysis. Role of water is intriguing as the reaction can be stopped at the intermediate stage. Synthesized compounds have been screened for possible antibacterial properties and results showed modest activity. 相似文献
112.
We express the number of ${\mathbb{F}_q}$ -points on the hyperelliptic curve ${\alpha{y}^2=\beta{x}^f + \gamma}$ in terms of Gaussian hypergeometric series. We also find some special values of ${{_{2}}F_1}$ -Gaussian hypergeometric series containing characters of order 3 and 4 as parameters. 相似文献
113.
Sandipan Talukdar Shubhranshu Zutshi K. S. Prashanth Kandarpa K. Saikia Parveen Kumar 《Applied biochemistry and biotechnology》2014,172(6):3026-3041
In the past few decades, genome-based approaches have contributed significantly to vaccine development. Our aim was to identify the most conserved and immunogenic antigens of Streptococcus pneumoniae, which can be potential vaccine candidates in the future. BLASTn was done to identify the most conserved antigens. PSORTb 3.0.2 was run to predict the subcellular localization of the proteins. B cell epitope prediction was done for the immunogenicity testing. Finally, BLASTp was done for verifying the extent of similarity to human proteome to exclude the possibility of autoimmunity. Proteins failing to comply with the set parameters were filtered at each step. Based on the above criteria, out of the initial 22 pneumococcal proteins selected for screening, pavB and pullulanase were the most promising candidate proteins. 相似文献
114.
Lakhinath Saikia Dhrubajyoti Talukdar Ramesh C. Deka Ashim J. Thakur 《Journal of heterocyclic chemistry》2013,50(5):1031-1038
KI‐VO(acac)2‐H2O2 in aqueous ethanolic medium with acetic acid as additive has been found to iodinate pyrimidinediones and aromatic amines. The methodology is mild, efficient, and environmentally benign. Density functional theory‐based reactivity parameters support the experimentally observed reactivity of pyrimidinedione derivatives. 相似文献
115.
New supported acidic organocatalysts were prepared by the impregnation of three carboxylic acids (CF3COOH, CCl3COOH, and CH3COOH) on silica support at room temperature in diethyl ether. The catalysts were characterized by scanning electron microscopy, energy dispersion X-ray analysis (EDX), Brunauer-Emmett-Teller-surface-area-analysis (BET), thermogravitational analysis, Fourier transform infrared, and powder X-ray diffractometry analysis. These solid acids were observed as highly efficient reusable catalysts at room temperature for the selective synthesis of β-amino carbonyl compounds via Mannich-type reactions of acetophenone, arylamine and arylaldehydes using two different conditions in CH2Cl2 solution and solvent-free grinding within a short time. The more acidic two catalysts could be recycled for up to five cycles with a small loss in catalytic activity. 相似文献
116.
The Ramanujan Journal - In this paper, we prove some new modular equations in the theory of signature 3 or cubic modular equations by using theta-function identities. Particularly, we prove modular... 相似文献
117.
It has been observed that Pd(0) can be used as a catalyst for the addition of CFBr3 to olefins to give 1,1,3-tribromo-1-fluoroalkanes with good yields. Both terminal and internal olefins react under these conditions. Treatment of the addition product with zinc and methanol gave 1,2-fluoroalkenes. 相似文献
118.
Reenamoni Saikia Chaliha K. Annapurna Anal Tarafder V.S. Tiwari P.K. Gupta Basudeb Karmakar 《Solid State Sciences》2009,11(8):1325-1332
In the present study, results concerning luminescence and dielectric properties of Eu2O3 (0.5 wt% in excess) doped nano-crystallized KNbO3 containing transparent glass-ceramics obtained from glass of composition 25K2O–25Nb2O5–50SiO2 (mol%) by varied heat-treatment duration at 800 °C have been analyzed and reported. The formed crystallization phase, crystallite size and morphology have been examined through XRD, FESEM, TEM and FTIRRS measurements. The observed steep increase in the dielectric constant (?) of glass-ceramics over the as-prepared glass is attributed to the formation of ferroelectric nano-crystalline KNbO3 in glass matrix. The absorption spectra of all the samples have revealed the characteristic 4f–4f intraband absorption transitions of Eu3+ ions. The measured photoluminescence spectra have exhibited emission transitions 5D0, 1 → 7Fj (j = 0, 1, 2, 3 and 4) of Eu3+ ions. The excited level lifetimes have been determined from measured fluorescence decay curves. The rare earth ion site symmetry (nearly Cv) has been understood based on the nature of the Stark splittings of emission bands detected in both Eu3+: glass and Eu3+: glass-ceramics. 相似文献
119.
We study the deterministic dynamics of a periodically driven particle in the underdamped case in a spatially symmetric periodic potential. The system is subjected to a space-dependent friction coefficient, which is similarly periodic as the potential but with a phase difference. We observe that frictional inhomogeneity in a symmetric periodic potential mimics most of the qualitative features of deterministic dynamics in a homogeneous system with an asymmetric periodic potential. We point out the need of averaging over the initial phase of the external drive at small frictional inhomogeneity parameter values or analogously low potential asymmetry regimes in obtaining ratchet current. We also show that at low amplitudes of the drive, where ratchet current is not possible in the deterministic case, noise plays a significant role in realizing ratchet current. 相似文献
120.
A study of Pentacene OTFTs using La2O3 as gate insulator is presented. The device characteristics were studied and analyzed. The OTFTs exhibit p-type conductivity with field effect mobility 6.5 × 10−8 m2/V.s, ON/OFF ratio 1.4 × 102, sub-threshold swing 2 mV/decade and hole concentration 4.5 × 1017 cm−3. The SEM and XRD analysis on the semiconductor film are also reported. 相似文献