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71.
The asymptotic analysis of linearly piezoelectric plates as the thickness approaches zero shows that, according to the type of boundary conditions considered, two distinct models of electromechanical behaviors may appear. We exhibit the influence of crystalline symmetries on the limit behavior. To cite this article: T. Weller, C. Licht, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 309–314. 相似文献
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Lopold Laitem Philippe Thibaut Lon Christiaens 《Journal of heterocyclic chemistry》1976,13(3):469-473
Starting from 2-bromo-5-methoxyacetophenone, an unambiguous synthesis of the selenium analog of serotonine is described with a 25% overall yield. Application of the Wittig reaction to selenoindoxyls appears to be a successful pathway to products of this nature. 相似文献
74.
Francis Blanche Beatrice Cameron Joel Crouzet Laurent Debussche Denis Thibaut Marc Vuilhorgne Finian J. Leeper Alan R. Battersby 《Angewandte Chemie (International ed. in English)》1995,34(4):383-411
Vitamin B12 is an essential vitamin for human health, and lack of it leads to pernicious anemia. This biological activity has attracted intense interest for some time; in addition, the complex architecture of the B12 molecule has fascinated chemists and biochemists since its discovery as the first natural organocobalt complex and the establishment of its structure by X-ray analysis. The organic ligand surrounding the cobalt displays many stereogenic centers along its periphery carrying reactive functional groups. This complexity led vitamin B12 to be rightly regarded as an extreme challenge to the synthetic chemist. Yet microorganisms achieve this synthesis in vivo with complete control of regio- and stereochemistry. How do they do it? This review tells the full remarkable story. Success in unraveling this biosynthetic puzzle resulted from a collaborative effort by biologists and chemists using the full range of methods available from their disciplines–from genetics at one end of the spectrum to synthesis and NMR spectroscopy at the other. This work can act as a guide for future research on the biosynthesis of yet more complex natural substances. 相似文献
75.
Indirect detection of photosensitizer ex vivo 总被引:2,自引:0,他引:2
Bourré L Thibaut S Briffaud A Rousset N Eléouet S Lajat Y Patrice T 《Journal of photochemistry and photobiology. B, Biology》2002,67(1):23-31
Photodynamic therapy induces the production of reactive oxygen species (ROS) within tissues exposed to laser light after administration of a sensitizer. In the context of continuing clinical and commercial development of chemicals with sensitizing properties, a minimally invasive assay is needed to determine the tissue kinetics of fluorescent or non-fluorescent photoreactive drugs. The level of ROS was determined ex vivo from 1 mm3 biopsy samples using 2'-7' dichlorofluorescin diacetate (DCFH-DA), a fluorescent probe which was converted into highly fluorescent dichlorofluorescein (DCF) in the presence of ROS. This assay was tested on meta(tetrahydroxyphenyl)chlorin (m-THPC, FOSCAN), a powerful and fluorescent sensitizer, and bacteriochlorophyll derivative WST09 (TOOKAD), a near-infrared absorbing sensitizer that is only slightly fluorescent. In conjunction with the ROS assay, the tissue accumulation of m-THPC was determined on biopsy samples using an optic fibre spectrofluorometer (OFS). DCF fluorescence was proportional to the level of oxidation induced by horseradish peroxidase used as a control and to the concentration (range: 0-5 microg x ml(-1)) of both selected photosensitizers irradiated in a tube together with DCFH. Regardless of the organ studied, an excellent correlation was found between fluorescence measurement by OFS and ROS determination for m-THPC. m-THPC (2 mg x kg(-1) iv) accumulation in tumour tissues was best after 48 h, and the best signal was obtained in liver. With non-fluorescent WST09 (2 mg x kg(-1)), ROS determination showed the best tumour uptake 48 h after injection, with a tumour/muscle ratio of 5.4. The ROS assay appears to be feasible for determining sensitizer concentration in regular grip biopsy tissue samples. 相似文献
76.
Delqué M Sylvestre T Maillotte H Cambournac C Kockaert P Haelterman M 《Optics letters》2005,30(24):3383-3385
We report the experimental observation of the elliptically polarized fundamental vector soliton of isotropic Kerr media and its unique polarization evolution. This was achieved in the spatial domain in a nonbirefringent CS2 planar waveguide. 相似文献
77.
Glaydston Mattos Ribeiro Guy Desaulniers Jacques Desrosiers Thibaut Vidal Bruno Salezze Vieira 《Journal of Heuristics》2014,20(6):677-708
Onshore oil fields may contain hundreds of wells that use sophisticated and complex equipments. These equipments need regular maintenance to keep the wells at maximum productivity. When the productivity of a well decreases, a specially-equipped vehicle called a workover rig must visit this well to restore its full productivity. Given a heterogeneous fleet of workover rigs and a set of wells requiring maintenance, the workover rig routing problem (WRRP) consists of finding rig routes that minimize the total production loss of the wells over a finite horizon. The wells have different loss rates, need different services, and may not be serviced within the horizon. On the other hand, the number of available workover rigs is limited, they have different initial positions, and they do not have the same equipments. This paper presents and compares four heuristics for the WRRP: an existing variable neighborhood search heuristic, a branch-price-and-cut heuristic, an adaptive large neighborhood search heuristic, and a hybrid genetic algorithm. These heuristics are tested on practical-sized instances involving up to 300 wells, 10 rigs on a 350-period horizon. Our computational results indicate that the hybrid genetic algorithm outperforms the other heuristics on average and in most cases. 相似文献
78.
Jonas Croissant Dr. Marie Maynadier Audrey Gallud Dr. Harmel Peindy N'Dongo Dr. Jeff L. Nyalosaso Dr. Gaëlle Derrien Dr. Clarence Charnay Dr. Jean‐Olivier Durand Dr. Laurence Raehm Prof. Françoise Serein‐Spirau Dr. Nathalie Cheminet Dr. Thibaut Jarrosson Dr. Olivier Mongin Dr. Mireille Blanchard‐Desce Dr. Magali Gary‐Bobo Dr. Marcel Garcia Dr. Jie Lu Prof. Fuyuhiko Tamanoi Dr. Derrick Tarn Tania M. Guardado‐Alvarez Prof. Jeffrey I. Zink 《Angewandte Chemie (International ed. in English)》2013,52(51):13813-13817
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Nonlinear Dynamics - The objective of this paper is the realization of a desired frequency–amplitude dependence of a specific vibration mode of a nonlinear system. To this end, we introduce... 相似文献