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Manorama Singh Anjumala Sahu Puneet K. Singh Fooleswar Verma Ankita Rai Vijai K. Rai 《Electroanalysis》2020,32(7):1516-1523
Herein, design and synthesis of ternary gold nanoparticles@ sulfourea‐functionalized reduced graphene oxide (Gold‐NPs@SFG) is reported. It involves interaction of ‘sulfourea’ to the graphene sheets via amidation of edged carboxyls of graphene oxide with N‐terminals of sulfourea followed by association of Gold‐NPs. Sulfourea not only reduced the graphene oxide but interestingly, it is functionalized to graphene sheets via carbodiimide covalent junctions, which gives it local effect to increase the active surface area and excellent electrocatalytic properties. The prepared nanocomposite was characterized with SEM, TEM, FTIR, Raman, XRD, XPS and CV. Gold‐NPs@SFG was found to be more efficient electrocatalyst for the electrocatalytic oxidation of a drug ‘Acetaminophen’ using differential pulse voltammetry and it was employed as a highly sensitive and selective electrochemical sensor for the quantification of ‘Acetaminophen’ with the detection limit of 0.09 μM in the wide linear range of 1.2 to 300 μM. 相似文献
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A novel and expeditious synthetic protocol for functionalized pyrimidines using unprotected aldoses as biorenewable resources is reported. The synthesis involves aza-Michael addition of aromatic amines to aldose-derived 1,3-oxazin-2-ones(thiones) followed by dehydrative ring transformation to afford 4-polyhydroxyalkylpyrimidin-2-ones(thiones) in excellent yields. This is a one-pot Montmorillonite K-10 clay-catalyzed amine-driven process proceeding under solvent-free microwave irradiation conditions. 相似文献
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Abhishek Bhattacharya Ankita Shrivastava Anjana Sharma 《Applied biochemistry and biotechnology》2013,170(4):756-773
Carbonic anhydrase (CA) was purified from Micrococcus lylae and Micrococcus luteus with 49.90 and 53.8 % yield, respectively, isolated from calcium carbonate kilns. CA from M. lylae retained 80 % stability in the pH and temperature range of 6.0–8.0 and 35–45 °C, respectively. However, CA from M. luteus was stable in the pH and temperature range of 7.5–10.0 and 35–55 °C, respectively. Cross-linked enzyme aggregates (CLEAs) raised the transition temperature of M. lylae and M. luteus CA up to 67.5 and 74.0 °C, while the operational stability (T 1/2) of CA at 55 °C was calculated to be 7.7 and 12.0 h, respectively. CA from both the strains was found to be monomeric in nature with subunit molecular weight and molecular mass of 29 kDa. Ethoxozolamide was identified as the most potent inhibitor based on both IC50 values and inhibitory constant measurement (K i). The K m and V max for M. lylae CA (2.31 mM; 769.23 μmol/mg/min) and M. luteus CA (2.0 mM; 1,000 μmol/mg/min) were calculated from Lineweaver–Burk plots in terms of esterase activity. Enhanced thermostability of CLEAs alleviates its role in operational stability for application at an on-site scrubber. The characteristic profile of purified CA from Micrococcus spp. advocates its effective application in biomimetic CO2 sequestration. 相似文献
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Rumpa Saha Sumanta K. Ghosh Aniruddha Ghosh Indrajit Saha Kakali Mukherjee Ankita Basu Bidyut Saha 《Research on Chemical Intermediates》2013,39(2):631-643
Chromic acid oxidation of dl-mandelic acid in the presence and absence of different promoters has been studied in aqueous media under the kinetic conditions [mandelic acid]T ? [Cr(VI)]T and [promoter]T ? [Cr(VI)]T at 30 °C. The promoters used in this oxidation reaction, picolinic acid (PA), 2,2′-bipyridine (bpy), and 1,10-phenanthroline (phen), are strong chelating ligands which form complexes with most transition metal ions. The reaction is first-order with regard to [H+], [mandelic acid]T, and [Cr(VI)]T and also has first-order dependence on [promoter]T. HCrO4 ? was found to be kinetically active in the absence of promoters; in the presence of promoters the Cr(VI)–promoter complexes were believed to be the active oxidants. In this path the Cr(VI)-promoter complex in each case undergoes nucleophilic attack by the mandelic acid to form a ternary complex which subsequently undergoes redox decomposition involving 3e transfer as the rate-determining step. Among the three promoters oxidation is much faster with 1,10-phenanthroline. 相似文献
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Ankita Singh Vipin K. Maikhuri Vineet Verma Rajni Johar Chhatwal Deepti Sharma 《合成通讯》2020,50(18):2787-2795
AbstractHere in, the condensation of boc-glycine with 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitol followed by its boc-deprotection to form 2,6-anhydro-3,4,5-tri-O-benzyl-D-gluco-heptitolyl bis-glycinate, which in turn on condensation with succinic acid/pyridine-2,6-dicarboxylic acid led to the formation of sugar-amino acid hybrid macrocyclic compounds 4, 6 and debenzylated marocyclic compound 5, having amide bonds that function as efficient host for polar, hydrogen bond acceptors and carboxylate ions. The anion inclusion capability of synthesized macrocylic hosts has been evaluated by the study of their binding with boc-GlyCOOˉ anion as guest through 1H NMR titration studies in CDCl3. The binding constant (Ka) of boc-GlyCOOˉ guest with macrocyclic hosts 4 and 6 involving succinate and pyridine-2,6-dicarboxylate linkers was found to be 9.201?×?103 and 1.437?×?104 M?1, respectively. The higher binding constant was observed in the complex of boc-GlyCOOˉ with pyridine-dicarboxylate containing host may be due to the extra rigidity & suitable conformation attained by the presence of rigid-aromatic dicarboxylate linker. 相似文献
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Ankita Shukla Mani Mehra Günter Leugering 《Mathematical Methods in the Applied Sciences》2020,43(13):7595-7614
Water wave propagation in an open channel network can be described by the viscous Burgers' equation on the corresponding connected graph, possibly with small viscosity. In this paper, we propose a fast adaptive spectral graph wavelet method for the numerical solution of the viscous Burgers' equation on a star-shaped connected graph. The vital feature of spectral graph wavelets is that they can be constructed on any complex network using the graph Laplacian. The essence of the method is that the same operator can be used for the construction of the spectral graph wavelet and the approximation of the differential operator involved in the Burgers' equation. In this paper, two test problems are considered with homogeneous Dirichlet boundary condition. The numerical results show that the method accurately captures the evolution of the localized patterns at all the scales, and the adaptive node arrangement is accordingly obtained. The convergence of the given method is verified, and efficiency is shown using CPU time. 相似文献
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Sandip Kumar Samanta Syed Samim Ali Ankita Gangopadhyay Kalipada Maiti Ajoy Kumar Pramanik Uday Narayan Guria 《Supramolecular chemistry》2019,31(5):349-360
A 3-indolylacrylate derivative, 3-IA, prepared by connecting an ethyl acrylate in 3-position of indole has been synthesised and characterised. Ethyl acrylate moiety acts as the Michael acceptor towards H2S, and the resultant addition product then participates in intramolecular cyclisation with the ester group at 2-position to form another new heterocyclic ring. Blue fluorescence of 3-IA turned into green in presence of H2S, leading to ratiometric behaviour of the fluorescent sensor with large stokes shift of 55 nm. Probe 3-IA has excellent selectivity towards H2S over other biothiols and other competing anions. Density function theory/time-dependent density function theory calculations were carried out to validate the reaction mechanism and the electronic properties of 3-IA. Importantly, the ratiometric probe 3-IA shows great promise in H2S detection by simple visual fluorescent inspection in filter paper-based protocol. The probe shows its excellent ability to detect H2S in different natural water samples. Furthermore, we have employed our probe to detect H2S for ratiometric imaging in live Vero cell. 相似文献