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排序方式: 共有303条查询结果,搜索用时 171 毫秒
111.
Banupriya Cinnasamy Srinivasan Krishnan Rajasekar Aruliah Murugan Kadarkarai Giovanni Benelli Dinakaran Kannaiyan 《中国化学快报》2017,28(7):1399-1405
Nowadays, the rapid and effective detection of low doses of heavy metal pollutants in contaminated water is a timely challenge in environmental pollution research. In this study, a rapid and highly sensitive assay for the detection of Hg~(2+)based on quenching of metal-enhanced fluorescence of rhodamine B(RB)has been fabricated. RB and silver nanoparticle were incorporated into the mesoporous siliceous framework spin cast on a quartz glass through post-synthetic incorporation method. The morphology and crystallinity of mesoporous structure and Ag nanoparticle were characterized by transmission electron microscopy and X-ray diffraction analyses. Photoluminescence assays on the hybrid thin film of RB-Ag-SBA15 showed a high enhancement when compared to the intensity of silver free SBA15-RB in the wavelength of 575 nm. The fluorescence of RB-Ag-SBA15 thin film decreased gradually with the increase in the concentration of Hg~(2+)and the detection limits were 10.54 nmol/L. Furthermore, the fluorescence intensity increased linearly with the concentration of Hg~(2+)in the range from 1.0 ? 10à8mol/L to10 ? 10à8mol/L, with a response time of a few seconds. In addition, this system offers a high selectivity over interfering cations such as Cd~(2+) and Pb~(2+). Overall, we have developed an optical assay having a wellordered mesoporous SBA15 containing Ag-RBfor selective detection of Hg~(2+)in aqueous solution. The scheme combines the advantages of specific binding interactions between Hg~(2+)and RB molecule and optical emission properties of RB. The method is suitable for a single-shot and irreversible analytical assay in a quartz glass/microtiter plate. 相似文献
112.
Density functional evaluation and a feasibility study of intramolecular thione–thiol tautomerization 下载免费PDF全文
Performance of various density functionals for use in geometry and energetics calculation of thiocarbonyl systems is evaluated. The three biologically significant systems such as 2‐methyl‐3‐thiosemicarbazide, 1‐acetyl‐2‐thiohydantoin and bornane‐2‐thione are selected for the geometry analysis. Energy of tautomerization of thioacetone and enthalpy of formation of 2‐thiohydantoin are considered for analyzing the performance in energetics. Minnesota functionals such as M05‐2X, M06‐2X and range separated hybrid functional wB97 give best results in both geometry and energetics calculations. Studies on basis set effect showed reliable performance by 6‐31 + G* and 6‐31++G** over higher basis sets. Feasibility of tautomerization in the aforementioned thiones has been investigated using the best performing density functionals. The proposed thione–thiol tautomerization step during PPC‐DC catalyzed decarboxylation reaction has also been investigated and the computed high energy barrier shows less feasibility of the reaction. 相似文献
113.
114.
Thangaraj Anand Gandhi Sivaraman Murugan Iniya Ayyanar Siva Duraisamy Chellappa 《Analytica chimica acta》2015
Chemosensors based on aminobenzohydrazide Schiff bases bearing pyrene/anthracene as fluorophores have been designed and synthesized for F− ion recognition. The addition of fluoride ions to the receptors causes a dramatically observable colour change from pale yellow to brown/red. 1H NMR studies confirm that the F− ion facilitates its recognition by forming hydrogen bond with hydrogens of amide and amine groups. Moreover these sensors have also been successfully applied to detection of fluoride ion in commercial tooth paste solution. 相似文献
115.
Gayathri V Ananthi S Chandronitha C Sangeetha MK Vasanthi HR 《Natural product research》2011,25(11):1110-1114
Nerium oleander Linn. (NO), an evergreen shrub, is used in folklore medicine as a cardiotonic and exhibits a wide spectrum of bioactivities. Herein, the hypolipidemic potential of the ethanolic extract of flowers of Nerium oleander (ENO) in a minimal dose was assessed. A high fat diet (HFD) resulted in a significant increase in cardiac lipids and lipoproteins and an increase in body weight gain. Simultaneous treatment with ENO significantly lowered the increase in body weight gain, lipid and lipoprotein levels, with a concomitant increase in HDL in the plasma and heart when compared to HFD-fed rats. Likewise, the activities of lipolytic enzymes were also upheld by the ENO treatment in the heart compared to HFD-fed rats. The above findings highlight the possible mechanism of N. oleander as a hypolipidemic agent in its use in folklore medicine as a cardiotonic. 相似文献
116.
N. Janani S. Ramakumar L. Dhivya C. Deviannapoorani K. Saranya Ramaswamy Murugan 《Ionics》2011,17(7):575-580
Polycrystalline cubic Li7La3Zr2O12 (LLZ) with garnet-related type structure has been synthesized at 700 °C by modified sol–gel processes using citric acid as
organic complexing agent and butan-1-ol or propan-2-ol as surface active agent. Thermal analysis (thermogravimetric/differential
thermal analysis) indicated that the gel must be annealed at around 700 °C to completely remove the organic solvent. X-ray
powder diffraction, X-ray fluorescence, and scanning electron microscopic investigations revealed that Al may not be essential
to form cubic-phase LLZ; however, the addition of Al2O3 led to enhanced sintering of LLZ. 相似文献
117.
Two multiwalled carbon nanotube hybrids have been prepared: (a) multiwalled carbon nanotubes (MWCNTs) functionalized with amphiphilic poly(propyleneimine) dendrimer (APPI), viz. MWCNTs-APPI, and (b) silver nanoparticles (AgNPs)-deposited multiwalled carbon nanotubes functionalized with an amphiphilic poly(propyleneimine) dendrimer (MWCNTs-APPI-AgNPs). The degree of covalent functionalization of APPI in MWCNTs and deposition of AgNPs in MWCNTs-APPI were examined by Fourier transform infrared spectroscopy, zeta potential, scanning and high-resolution transmission electron microscopy, energy-dispersive spectroscopy, thermogravimetric analysis, and Raman spectroscopy. The amount of APPI functionalized on MWCNTs determined by thermal gravimetric analysis was about 67% which enables an effective dispersability in aqueous and organic solvents without sonication and these solutions were stable for 6 months without undergoing aggregation of MWCNTs. The electronic properties of the hybrid materials were not altered drastically as verified by the Raman studies. The antimicrobial activities of MWCNTs-APPI and MWCNTs-APPI-AgNPs against three different bacteria, viz. Bacillus subtilis, Staphylococcus aureus, and Escheriachia coli illustrated excellent activity. 相似文献
118.
Nair AS Zhu P Babu VJ Yang S Krishnamoorthy T Murugan R Peng S Ramakrishna S 《Langmuir : the ACS journal of surfaces and colloids》2012,28(15):6202-6206
We report the use of highly porous, dense, and anisotropic TiO(2) derived from electrospun TiO(2)-SiO(2) nanostructures through titanate route in dye-sensitized solar cells. The titanate-derived TiO(2) of high surface areas exhibited superior photovoltaic parameters (efficiency > 7%) in comparison to the respective electrospun TiO(2) nanomaterials and commercially available P-25. 相似文献
119.
In order to explore the possibilities of simulating metallochromism by modern molecular modeling, we apply a sequential hybrid quantum-classical approach to a prototype metallochromic system-the Al(3+) ion and pyrimidinedione (PY) dye complex. The complex shows several structural features with relevance for the metallochromism: the PY dye exhibits conformers with dynamical transitions between twisted structures, which are inhibited by the addition of the metal ion leading to planarization and a conformational arrest: the Al(3+) ion behaves like a structure-modifier for both intra and intermolecular degrees of freedom and with respect to the intermolecular solvation shell structure. The sequential approach that we have employed uses DFT/MM molecular dynamics for structure modeling and TDDFT/PCM for property modeling. The computed metallochromic shift between PY and the Al(PY)(3+) complex in DMSO solvent is obtained in excellent agreement with experiment. The results infer optimism for future use of such modeling techniques to design metallochromic indicators. 相似文献
120.
Sadashiva Maralinganadoddi Panchegowda Basappa NanjundaSwamy Shivananju Li Feng Manu Kanjoormana Aryan Sengottuvelan Murugan Prasanna Doddakunche Shivaramu Anilkumar Nirvanappa Chikkagundagal Sethi Gautam Sugahara Kazuyuki Rangappa Kanchugarakoppal Subbegowda 《BMC chemical biology》2012,12(1):1-11