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331.
Alcaraz G Euzenat L Mongin O Katan C Ledoux I Zyss J Blanchard-Desce M Vaultier M 《Chemical communications (Cambridge, England)》2003,(22):2766-2767
A series of octupolar molecules derived from the boroxine framework were designed and their optical nonlinearities were investigated by performing harmonic light scattering experiments in solution; the molecules were found to combine excellent transparency in the near UV-visible region (lambdamax < or = 280 nm) and significant first-order hyperpolarisabilities (up to beta(0) = 56 x 10(-30) esu). 相似文献
332.
Mireille Palpant Christian Artigues Philippe Michelon 《Annals of Operations Research》2004,131(1-4):237-257
This paper presents the Local Search with SubProblem Exact Resolution (LSSPER) method based on large neighbourhood search for solving the resource-constrained project scheduling problem (RCPSP). At each step of the method, a subpart of the current solution is fixed while the other part defines a subproblem solved externally by a heuristic or an exact solution approach (using either constraint programming techniques or mathematical programming techniques). Hence, the method can be seen as a hybrid scheme. The key point of the method deals with the choice of the subproblem to be optimized. In this paper, we investigate the application of the method to the RCPSP. Several strategies for generating the subproblem are proposed. In order to evaluate these strategies, and, also, to compare the whole method with current state-of-the-art heuristics, extensive numerical experiments have been performed. The proposed method appears to be very efficient. 相似文献
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335.
ENDOGENOUS GLUTATHIONE PROTECTS HUMAN SKIN FIBROBLASTS AGAINST THE CYTOTOXIC ACTION OF UVB, UVA AND NEAR-VISIBLE RADIATIONS 总被引:3,自引:0,他引:3
Both the UVB (290-320 nm) and UVA (320-380 nm) regions of sunlight damage human skin cells but, particularly at the longer wavelengths, information is scant concerning the mechanism(s) of damage induction and the roles of cellular defense mechanisms. Following extensive glutathione depletion of cultured human skin fibroblasts, the cells become strongly sensitized to the cytotoxic action of near-visible (405 nm), UVA (334 nm, 365 nm) and UVB (313 nm) but not UVC (254 nm) radiations. In the critical UVB region, the magnitude of the protection afforded by endogenous glutathione approaches that of the protection provided by excision repair. The results suggest that a significant fraction of even UVB damage can be mediated by free radical attack and that a major role of glutathione in human skin cells is to protect them from the cytotoxic action of sunlight. 相似文献
336.
"Light-up" probes, icosa-alpha-thymidylate-thiazole orange conjugates, for the in situ time-resolved detection of messenger ribonucleic acid (mRNA) in living cells are evaluated. Upon annealing with polyA in aqueous solutions, the icosa-alpha-thymidylate-thiazole orange conjugates were shown to be up to 15 times more fluorescent. Microinjection of these probes into adherent fibroblasts resulted in high yields of hybridization and fluorescent signals. Incubation of cells in the presence of these probes resulted in facile internalization of the probe and similar painting of the messenger RNA in the nuclear and cytosolic regions. 相似文献
337.
The influence of the mobile phase composition and column temperature on the chromatographic separation of five buckminsterfullerenes (C60, C70, C76, C78, C84) on a stationary phase based on silica gel with chemically bonded humic acid (Bonded humic acid column (BHAC)) was studied. The retention behavior of the fullerenes was measured under isocratic conditions with different mobile phase compositions, ranging from 0.05-0.70 (v/v) of toluene in cyclohexane. The column temperature was analysed in the range 35-75 °C. The retention factors of the five fullerenes do not depend linearly on the toluene fraction but follow a quadratic relationship. The best chromatographic conditions for baseline separation of the five fullerenes were selected. The retention of the fullerenes on the HA stationary phase was strongly affected by temperature. Positive values of thermodynamic parameters (changes of enthalpy and entropy) were due to the abnormal solubility behaviour of fullerenes in toluene in the temperature range 35-75 °C. The information obtained in this work makes this BHAC very simple to prepare and low cost, useful for fullerene research applications. 相似文献
338.
Starita-Geribaldi M Thebault P Taffin de Givenchy E Guittard F Geribaldi S 《Electrophoresis》2007,28(14):2489-2497
The synthesis of hemi-fluorinated zwitterionic surfactants was realized and assessed for 2-DE, a powerful separation method for proteomic analysis. These new fluorinated amidosulfobetaine (FASB-p,m) were compared to their hydrocarbon counterparts amidosulfobetaine (ASB-n) characterized by a hydrophilic polar head, a hydrophobic and lipophilic tail, and an amido group as connector. The tail of these FASB surfactants was in part fluorinated resulting in the modulation of its lipophilicity (or oleophobicity). Their effect on the red blood cell (RBC) membrane showed a specific solubilization depending on the length of the hydrophobic part. A large number of polypeptide spots appeared in the 2-DE patterns by using FASB-p,m. The oleophobic character of these surfactants was confirmed by the fact that Band 3, a highly hydrophobic transmembrane protein, was not solubilized by these fluorinated structures. The corresponding pellet was very rich in Band 3 and could then be solubilized by using a strong detergent such as amidosulfobetaine with an alkyl tail containing 14 carbon atoms (ASB-14). Thus, these hemi-fluorinated surfactants appeared as powerful tools when used at the first step of a two-step solubilization strategy using a hydrocarbon homologous surfactant in the second step. 相似文献
339.
340.
Monodispersed titanium oxide nanoparticles in N,N-dimethylformamide: water solutions 总被引:1,自引:0,他引:1
Hélène Terrisse Audry-Fred Bando Thomas Cottineau Luc Brohan Mireille Richard-Plouet 《Journal of Sol-Gel Science and Technology》2013,67(2):288-296
Because of both its complexing ability toward Ti cations and reactivity in highly acidic medium, N,N-dimethylformamide (DMF) can be used to control the hydrolysis and condensation of Titanium oxide frameworks, starting from Ti oxychloride as precursor. The addition of water allows promotion of hydrolysis of the aldehyde while controlling the size of the nanoparticles formed in the solution. The as-prepared colloidal solutions are very stable, up to 3 months, depending on the initial titanium concentration, the DMF/Water ratio, and the thermal treatment. The sol to gel transformation was monitored by viscosimetry measurements as a function of ageing time and heat treatment temperature. Optimization of pre-treatment at moderate temperature leads to fine control over the gelation process. 相似文献