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排序方式: 共有169条查询结果,搜索用时 16 毫秒
161.
Lazar HZ Forestier T Barrett SA Kilner CA Létard JF Halcrow MA 《Dalton transactions (Cambridge, England : 2003)》2007,(38):4276-4285
The syntheses of [FeL][BF(4)](2).H(2)O, [FeL][ClO(4)](2).H(2)O, [FeL][NO(3)](2).CH(3)NO(2) and [FeL][CF(3)SO(3)](2) (L = tris(4-{pyrazol-3-yl}-3-aza-3-butenyl)amine) are described. The isostructural BF(4)(-) and ClO(4)(-) salts are high-spin between 5-300 K, while the other two compounds are high-spin at room temperature but undergo gradual high-->low spin transitions upon cooling. For [FeL][NO(3)](2) this transition is centred at 139 K and proceeds to near-completeness, while for [FeL][CF(3)SO(3)](2) it is centred at 144 K and only proceeds to 50% conversion. The CF(3)SO(3)(-) salt also undergoes spin-crossover centred at 200 K in (CD(3))(2)CO solution, and exhibits dynamic inversion of its helical ligand conformation. All these compounds except the triflate salt have been crystallographically characterised, and show capped trigonal antiprismatic [6 + 1] coordination geometries. The NO(3)(-) and CF(3)SO(3)(-) salts undergo quantitative conversion to trapped, high-spin excited states upon irradiation with a green laser at 10 K (the LIESST effect; LIESST = Light-Induced Excited Spin State Trapping). The thermal stabilities of their LIESST excited states (T(LIESST) = 80-82 K) resemble those found for iron(ii) complexes of bidentate N-heterocyclic ligands. Hence, the LIESST properties of [FeL](2+) are those of a complex of three rigid bidentate domains linked by a flexible spacer, rather than of a single encapsulating podand. 相似文献
162.
163.
Nanostructuration of soft hydrogels: synthesis and characterization of saccharidic methacrylate gels
Seila Rodriguez Vilches Childérick Séverac Christophe Thibaut Lo?c Laplatine Christophe Vieu Juliette Fitremann Anne-Fran?oise Mingotaud Philippe Martinoty Dominique Collin 《Colloid and polymer science》2011,289(13):1437-1449
With the tremendous development of biosensors, there is a strong need in new biocompatible materials avoiding possible denaturing
of biological species, which can be easily processed with already existing technologies. The scope of this study was to develop
new hydrogels which could be nanostructured by common lithographic methods. Therefore, new methacrylate hydrogels are described,
which include functionalized monomers bearing either neutral groups, such as saccharidic moieties, anionic, or cationic groups.
The gels have been synthesized by redox or photochemical-initiated radical polymerization. Their porosity has been characterized
by thermoporometry, AFM, and electronic microscopy. The kinetics of the photocross-linking has been analyzed by piezorheometry
on some of the materials and has been shown to be compatible with technological process time range. Although the obtained
hydrogels are soft, their nanostructuration into 500-nm patterns could be performed by nanoimprint photolithography process,
and these patterns were observed to be stable for several months. 相似文献
164.
Diego Cattaruzza Nabil Absi Dominique Feillet Thibaut Vidal 《European Journal of Operational Research》2014
We consider the Multi Trip Vehicle Routing Problem, in which a set of geographically scattered customers have to be served by a fleet of vehicles. Each vehicle can perform several trips during the working day. The objective is to minimize the total travel time while respecting temporal and capacity constraints. 相似文献
165.
Protected α-alkyl lanthionine derivatives were synthesized in five steps starting from a known phenyloxazoline precursor. This approach involved the synthesis of a family of substituted cyclic sulfamidates and their regioselective opening by nucleophilic attack with a protected cysteine. This efficient multistep strategy affords various α-alkylated lanthionine derivatives in high yields. 相似文献
166.
Photophysical Properties of Ruthenium(II) Polypyridyl DNA Intercalators: Effects of the Molecular Surroundings Investigated by Theory
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Dr. Thibaut Véry Dr. David Ambrosek Miho Otsuka Dr. Christophe Gourlaouen Prof. Xavier Assfeld Dr. Antonio Monari Dr. Chantal Daniel 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(40):12901-12909
The environmental effects on the structural and photophysical properties of [Ru(L)2(dppz)]2+ complexes (L=bpy=2,2′‐bipyridine, phen=1,10‐phenanthroline, tap=1,4,5,8‐tetraazaphenanthrene; dppz=dipyrido[3,3‐a:2′,3′‐c]phenazine), used as DNA intercalators, have been studied by means of DFT, time‐dependent DFT, and quantum mechanics/molecular mechanics calculations. The electronic characteristics of the low‐lying triplet excited states in water, acetonitrile, and DNA have been investigated to decipher the influence of the environment on the luminescent behavior of this class of molecules. The lowest triplet intra‐ligand (IL) excited state calculated at λ≈800 nm for the three complexes and localized on the dppz ligand is not very sensitive to the environment and is available for electron transfer from a guanine nucleobase. Whereas the lowest triplet metal‐to‐ligand charge‐transfer (3MLCT) states remain localized on the ancillary ligand (tap) in [Ru(tap)2(dppz)]2+, regardless of the environment, their character is drastically modified in the other complexes [Ru(phen)2(dppz)]2+ and [Ru(bpy)2(dppz)]2+ upon going from acetonitrile (MLCTdppz/phen or MLCTdppz/bpy) to water (MLCTdppz) and DNA (MLCTphen and MLCTbpy). The change in the character of the low‐lying 3MLCT states accompanying nuclear relaxation in the excited state controls the emissive properties of the complexes in water, acetonitrile, and DNA. The light‐switching effect has been rationalized on the basis of environment‐induced control of the electronic density distributed in the lowest triplet excited states. 相似文献
167.
Marcos Melo Silva Anand Subramanian Thibaut Vidal Luiz Satoru Ochi 《European Journal of Operational Research》2012
The Minimum Latency Problem (MLP) is a variant of the Traveling Salesman Problem which aims to minimize the sum of arrival times at vertices. The problem arises in a number of practical applications such as logistics for relief supply, scheduling and data retrieval in computer networks. This paper introduces a simple metaheuristic for the MLP, based on a greedy randomized approach for solution construction and iterated variable neighborhood descent with random neighborhood ordering for solution improvement. Extensive computational experiments on nine sets of benchmark instances involving up to 1000 customers demonstrate the good performance of the method, which yields solutions of higher quality in less computational time when compared to the current best approaches from the literature. Optimal solutions, known for problems with up to 50 customers, are also systematically obtained in a fraction of seconds. 相似文献
168.
Dana Kumprechtov Thibaut Chabrillat Simon Guillaume Sylvain Kerros Romana Kadek Eva Indrov Josef Illek 《Molecules (Basel, Switzerland)》2022,27(18)
(1) Background: This study evaluated the effects of a plant bioactive (Phyto Ax’Cell, Phytosynthese, Mozac, France) on the inflammatory status and health of dairy cows during calving. (2) Methods: 46 Holstein crossbred cows were randomized into a control group (CON, n = 23) and the Phyto Ax’Cell group (PAC, n = 23). PAC received Phyto Ax’Cell at 25 g/cow/day, from 15 days prepartum to 7 days postpartum. Blood analyses were performed weekly from D-7 to D14 to evaluate the energy metabolism and inflammatory status; rectal temperature was measured daily within 14 days from calving day (D0). (3) Results: PAC showed lower serum haptoglobin at D7 (0.55 vs. 0.79 mg/mL; p < 0.05) and D14 (0.44 vs. 0.66 mg/mL; p < 0.05). CON had a higher number of circulating white blood cells and granulocytes on D7 (p < 0.05). Fewer cows from PAC showed hyperthermia (≥39 °C) during the first 2 weeks postpartum (−7%, p < 0.05). Energy metabolism, which was represented by the NEFA/cholesterol ratio, improved (0.21 vs. 0.36 at D0, p < 0.1; 0.19 and 0.15 vs. 0.36 and 0.32, respectively, at D+7 and D+14, p < 0.05) under the plant bioactive supplementation. (4) Conclusions: The results suggest that the anti-inflammatory plant bioactive compound with Brazilian green propolis administered during calving had a beneficial effect on the energy and inflammatory status of dairy cows. 相似文献
169.