排序方式: 共有74条查询结果,搜索用时 15 毫秒
1.
K. Devika R. Chandrika Srirupa Mukherjee D. Padmanabhan V. K. P. Unny N. Sivaprasad 《Journal of Radioanalytical and Nuclear Chemistry》2006,267(3):581-583
Summary Tritiated uracil and uridine have been prepared simultaneously from a mixture of their respective halogenated analogues (5-bromouracil
and5-bromouridine) by halogen-tritium exchange in a one pot preparation, followed by purification. The tritiated products
thus obtained have specific activities of 0.962 TBq/mmol and 1.036 TBq/mmol, respectively. 相似文献
2.
We report synthesis of temperature- and redox-responsive multiblock copolymers by reversible addition-fragmentation chain transfer (RAFT) polymerization. Well-defined α,ω-bis(dithioester)-functionalized poly(N-isopropylacrylamide) (PNIPAM) and poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) were prepared using 1,4-bis(thiobenzoylthiomethyl)benzene and 1,4-bis(2-(thiobenzoylthio)prop-2-yl)benzene as RAFT agents, respectively. Dually responsive multiblock copolymers were synthesized in a single aminolysis/oxidation step from the α,ω-bis(dithioester)-terminated PNIPAM and PDMAEMA. The copolymers and their stimulus-responsive behavior were characterized by size exclusion chromatography, NMR, light scattering and atomic force microscopy. Due to the presence of redox-sensitive disulfide bonds between the blocks, the copolymers were readily reduced to the starting polymer blocks. The presence of temperature-responsive PNIPAM blocks provided the copolymers with the ability to assemble into core-shell nanostructures with hydrophobic PNIPAM as a core and cationic PDMAEMA as stabilizing shell when above the phase transition temperatures of PNIPAM. The temperature-induced assembly of the copolymers also showed substantial pH sensitivity. The phase transition temperature increased with decreasing pH, while molecular weight of the assemblies decreased. 相似文献
3.
Trans‐1,2‐cyclohexanediol and trans‐2‐aminocycloxexanol are useful chiral auxiliaries. Simple chemical resolution procedures for these molecules are presented. 相似文献
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5.
Shailajan Sunita Hande Harshada Joshi Harshvardhan Tiwari Bhavesh Menon Sasikumar 《平面色谱法杂志一现代薄层色谱法》2014,27(1):23-28
JPC – Journal of Planar Chromatography – Modern TLC - Marmelosin is one of the major phytochemical constituents of Aegle marmelos (L.) Corr. (Rutaceae). Till date, there are no methods... 相似文献
6.
Vadapalli Chandrasekhar Palani Sasikumar Puja Singh Ramalingam Thirumoorthi Tapas Senapati 《Journal of Chemical Sciences》2008,120(1):105-113
Organostannoxane cages and aggregates of well-defined composition and structure can be prepared by the reactions of organotin
oxides or organotin oxide-hydroxides with protic acids. The utility of this strategy for the preparation of dendrimer-like
molecules containing a stannoxane core and a functional periphery is described. 相似文献
7.
K. Devika R. Chandrika D. Padmanabhan V. K. P. Unny N. Sivaprasad 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(3):507-508
Summary Tritiated fluorenone 2 was prepared from 2-iodofluorenone 1 by halogen-tritium exchange. The product had specific activity
of 17 Ci/mmol. The product 2(after dilution with unlabeled congener) on reduction with NaBH4gave the corresponding tritiated fluorenol 3. 相似文献
8.
Devika Kannan Ana Beatriz Lopes de Sousa Jabbour Charbel José Chiappetta Jabbour 《European Journal of Operational Research》2014
Due to an increased awareness and significant environmental pressures from various stakeholders, companies have begun to realize the significance of incorporating green practices into their daily activities. This paper proposes a framework using Fuzzy TOPSIS to select green suppliers for a Brazilian electronics company; our framework is built on the criteria of green supply chain management (GSCM) practices. An empirical analysis is made, and the data are collected from a set of 12 available suppliers. We use a fuzzy TOPSIS approach to rank the suppliers, and the results of the proposed framework are compared with the ranks obtained by both the geometric mean and the graded mean methods of fuzzy TOPSIS methodology. Then a Spearman rank correlation coefficient is used to find the statistical difference between the ranks obtained by the three methods. Finally, a sensitivity analysis has been performed to examine the influence of the preferences given by the decision makers for the chosen GSCM practices on the selection of green suppliers. Results indicate that the four dominant criteria are Commitment of senior management to GSCM; Product designs that reduce, reuse, recycle, or reclaim materials, components, or energy; Compliance with legal environmental requirements and auditing programs; and Product designs that avoid or reduce toxic or hazardous material use. 相似文献
9.
Devika Sil Rimlee Deb Roy Sunirmal Jana Rabibrata Mukherjee Shyamal Kumar Bhadra Prasanta Kumar Biswas 《Journal of Sol-Gel Science and Technology》2011,59(1):117-127
Patterning of sol gel based silica and silica–titania films has been developed at room temperature by soft lithographic technique.
Corresponding metal alkoxides have been utilized for the preparation of precursor sols. Elastomeric stamps of polydimethylsiloxane
(PDMS) are used to emboss patterns of a master grating on the as-prepared silica and silica–titania films obtained by sol
gel process. Pressure-less capillary force lithography has been used to fabricate both 1-D and 2-D ordered structures of simple
stripe patterns. A modified solvent assisted lithography and micro-molding in capillaries yielded stable and high fidelity
1-D structures for silica and silica–titania films over a large area. 相似文献
10.
Vadapalli Chandrasekhar Kandasamy Gopal Loganathan Nagarajan Palani Sasikumar Pakkirisamy Thilagar 《Journal of Chemical Sciences》2006,118(6):455-462
Phosphonate ligands, [RPO3]2-, are extremely versatile in the assembly of multi-tin and multi-copper architectures. We have used organostannoxane cores
for supporting multi-ferrocene and multi-porphyrin peripheries. The copper-metalated multi-porphyrin compound is an excellent
reagent for facile cleavage of DNA, even in the absence of a co-oxidant. Reaction oft-BuPO3H2 with Cu(C104)2. 6H2O in the presence of 2-pyridylpyrazole (2-Pypz) leads to the synthesis of a decanuclear copper (II) assembly. 相似文献