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121.
Shyamaprosad Goswami Avijit Kumar Das Krishnendu Aich Abhishek Manna Hoong-Kun Fun Ching Kheng Quah 《Supramolecular chemistry》2013,25(2):94-104
A simple novel receptor, designed to have a combination of both oxygen and nitrogen-binding sites for metal ion and hydrogen bond donor sites for anion, was synthesised. The receptor has been explored for the selective detection of cation Al3+ over the other interfering metal ions and anion AcO? against a range of physiologically relevant anions in the fluorescence spectroscopy. The receptor shows a different response to aluminium and acetate in the emission spectra. The binding isotherm and detection limit demonstrate that the receptor is an excellent fluorometric probe for Al3+ and AcO? . 相似文献
122.
Mohana Krishna Reddy Mudiam Abhishek Chauhan Krishna P. Singh Shailendra K. Gupta Rajeev Jain Ratnasekhar Ch R. C. Murthy 《Analytical and bioanalytical chemistry》2013,405(1):341-349
The present communication describes the preparation and evaluation of a molecularly imprinted polymer (MIP) as a solid-phase extraction (SPE) sorbent and simultaneous ethyl chloroformate (ECF) derivatization and pre-concentration by dispersive liquid–liquid microextraction (DLLME) for the analysis of t,t-muconic acid (t,t-MA) in urine samples using gas chromatography–mass spectrometry. The imprinting polymer was prepared using methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, 2,2-azobisisobutyronitrile as the initiator and t,t-MA as a template molecule. The imprinted polymer was evaluated for its use as a SPE sorbent by comparing both imprinted and non-imprinted polymers in terms of the recovery of t,t-MA from urine samples. Molecular modelling studies were performed in order to estimate the binding energy and efficiency of the MIP complex formed between the monomer and the t,t-MA. Various factors that can affect the extraction efficiency of MIP, such as the loading, washing and eluting conditions, were optimized; other factors that can affect the derivatization and DLLME pre-concentration were also optimized. MIP in combination with ECF derivatization and DLLME pre-concentration for t,t-MA exhibits good linearity, ranging from 0.125 to 2 μg?mL?1 (R 2?=?0.9971), with limit of detection of 0.037 μg?mL?1 and limit of quantification of 0.109 μg?mL?1. Intra- and inter-day precision was found to be <6 %. The proposed method has been proven to be effective and sensitive for the selective pre-concentration and determination of t,t-MA in urine samples of cigarette smokers. Figure
Graphical abstract for t,t-muconic acid analysis by using MISPE-DLLME followed by GC-MS analysis 相似文献
123.
Synthesis,Pharmacological, and Biological Screening of Novel Derivatives of Benzodiazepines
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K. Ishwar Bhat Manoj Kumar Singh Chauhan Abhishek Kumar Pankaj Kumar 《Journal of heterocyclic chemistry》2014,51(4):1189-1192
A series of novel 4‐(substituted phenyl)‐2‐(thiophen‐2‐yl)‐2,3‐dihydro‐1H‐benzo[b][1,4]diazepine have been synthesized from 3‐(substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one. 3‐(Substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one was prepared by condensing 2‐acetyl thiophene with various aromatic aldehydes in the presence of 20% NaOH as base. Different 3‐(substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one on cyclization with o‐phenylenediamine in the presence of NaOH as base resulted in 4‐(substituted phenyl)‐2‐(thiophen‐2‐yl)‐2,3‐dihydro‐1H‐benzo[b][1,4]diazepine derivatives. The structures of synthesized compounds are confirmed by IR, 1H NMR, mass spectra, and elemental analysis. All the compounds have been screened for their antimicrobial, analgesic, and anti‐inflammatory activities. 相似文献
124.
Czechoslovak Mathematical Journal - Let Dm be an elliptic curve over ? of the form y2 = x3 ? m2x + m2, where m is an integer. In this paper we prove that the two points P?1 =... 相似文献
125.
Abstract
The versatility of nitroaliphatics is demonstrated by using it in the syntheses of artemisinin derived dimers. A few novel artemisinin derived dimer and monomer have been synthesized using nitroalkane as linker. 相似文献126.
Single file translocation of a homopolymer through an active channel under the presence of a driving force is studied using Langevin dynamics simulation. It is shown that a channel with sticky walls and oscillating width could lead to significantly more efficient translocation as compared to a static channel that has a width equal to the mean width of the oscillating pore. The gain in translocation exhibits a strong dependence on the stickiness of the pore, which could allow the polymer translocation process to be highly selective. 相似文献
127.
Hazra AB Han Y Chatterjee A Zhang Y Lai RY Ealick SE Begley TP 《Journal of the American Chemical Society》2011,133(24):9311-9319
In many bacteria tenI is found clustered with genes involved in thiamin thiazole biosynthesis. However, while TenI shows high sequence similarity with thiamin phosphate synthase, the purified protein has no thiamin phosphate synthase activity, and the role of this enzyme in thiamin biosynthesis remains unknown. In this contribution, we identify the function of TenI as a thiazole tautomerase, describe the structure of the enzyme complexed with its reaction product, identify the substrates phosphate and histidine 122 as the acid/base residues involved in catalysis, and propose a mechanism for the reaction. The identification of the function of TenI completes the identification of all of the enzymes needed for thiamin biosynthesis by the major bacterial pathway. 相似文献
128.
Boess E Sureshkumar D Sud A Wirtz C Farès C Klussmann M 《Journal of the American Chemical Society》2011,133(21):8106-8109
The mechanism of an aerobic copper-catalyzed oxidative coupling reaction with N-phenyl tetrahydroisoquinoline was investigated. The oxidized species formed from the reaction of the amine with the copper catalyst were analyzed by NMR-spectroscopy. An iminium dichlorocuprate was found to be the reactive intermediate and could be structurally characterized by X-ray crystallography. The effect of methanol to effectively stabilize the iminium ion was investigated and shown to be beneficial in an oxidative allylation reaction. 相似文献
129.
Ayushi Mittal Abhishek K. Singh Anoop Kumar Parmanand Katharina Achazi Rainer Haag Sunil K. Sharma 《先进技术聚合物》2020,31(6):1208-1217
Herein, we report on the synthesis of a new class of novel non‐ionic amphiphiles using triglycerol as a core, which is further functionalized with hydrophilic units poly(ethylene glycol) monomethyl ether (Mn: 350 and 550) and a pair of hydrophobic alkyl chains (C18 or C15) via chemo‐enzymatic approach. Fluorescence measurements and dynamic light scattering studies showed that all of the synthesized amphiphilic systems spontaneously self‐ assemble in aqueous solution, which is further confirmed by the transmission electron microscopy. Encapsulation of hydrophobic moieties like Nile red and nimodipine was studied using ultraviolet‐visible (UV‐vis) and fluorescence spectrometer techniques. A cytotoxicity study of the amphiphiles using A549, HeLa, and MCF7 cell, which showed that all of the synthesized nanocarriers are well tolerated at the concentrations studied. The release profile of encapsulated Nile red in synthesized amphiphilic system was studied in the presence of the immobilized enzyme (Novozym 435). 相似文献
130.
CFD analysis for thermo-hydraulic properties in a tubular heat exchanger using curved circular rings
Singh Satyendra Kharkwal Himanshi Gautam Abhishek Pandey Ashutosh 《Journal of Thermal Analysis and Calorimetry》2020,141(6):2211-2218
Journal of Thermal Analysis and Calorimetry - The never-ending demands of humans have led researchers to find more efficient energy conversion technologies. Enhancing heat transfer rate in a... 相似文献