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811.
Annie-Francoise Maggio Marc Lucas Jean-Louis Barascut Jean-Louis Imbach 《Tetrahedron letters》1984,25(30):3195-3198
Appropriate protected deoxyguanosine and deoxyuridine derivatives, respectively activated at O6 and O4 positions by the 3-nitro 1,2,4-triazol 1-yl group, were reacted with ethylene glycol, ethylenediamine or ethanolamine to give monoalkylated nucleosides or cross-linked dimers or cross-linked dinucleosides. 相似文献
812.
Antoine Bechalany Nabil El Tayar Pierre-Alain Carrupt Bernard Testa Jean-Bernard Falconnet Yahia Cherrah Youssef Benchekroun Jean-Louis Brazier 《Helvetica chimica acta》1989,72(3):472-476
In the present study, it is confirmed that the deuteration of C? H groups is accompanied by a small but genuine decrease in lipophilicity. The lipophilicity of deuterated isotopomers of caffeine was measured by reversed-phase HPLC. Overall, lipophilicity was shown to decrease when going from unlabelled caffeine to the three isomeric trideuterated caffeines, then to the three isomeric hexadeuterated caffeines, and finally to nonadeuterated caffeine. In addition, position-specific effects were also proven. E.g. (7-methyl-2H3)caffeine experienced a smaller isotope effect than its two positional isomers. Both a cavity factor (decreased volume of deuterated isotopomers) and intramolecular electronic effects are postulated to operate. 相似文献
813.
Jean-Louis Calais 《International journal of quantum chemistry》1989,35(6):735-743
Since the overlap integral between two functions in position space is the same as the overlap integral between their counterparts in momentum space, there is an intimate connection between orthonormalization procedures in the two spaces. It is pointed out that in certain cases this situation can be used to simplify the orthogonalization. 相似文献
814.
Jean-Louis Colliot-Thé lè ne Bjorn Poonen 《Journal of the American Mathematical Society》2000,13(1):83-99
Principal homogeneous spaces under an abelian variety defined over a number field may have rational points in all completions of the number field without having rational points over . Such principal homogeneous spaces represent the nonzero elements of the Shafarevich-Tate group of the abelian variety.
We produce nontrivial, one-parameter families of such principal homogeneous spaces. The total space of these families are counterexamples to the Hasse principle. We show these may be accounted for by the Brauer-Manin obstruction.
815.
Jean-Philippe Tourrenc Sophie Bouchoule Aghiad Khadour Jean-Christophe Harmand Audrey Miard Jean Decobert Nadine Lagay Xavier Lafosse Isabelle Sagnes Laetitia Leroy Jean-Louis Oudar 《Optical and Quantum Electronics》2008,40(2-4):155-165
We report on the thermal design and the characterization of InP-based 1.55 μm wavelength large diameter (~100 μm) optically pumped vertical external cavity surface emitting lasers (OP-VECSELs). The device is thermally optimized for high power ( > 70 mW) room-temperature (RT) continuous-wave (CW) single-mode operation. Efficient bottom heat dissipation in the 1/2-VCSEL chip is obtained thanks to the use of a hybrid metal– metamorphic GaAs/AlAs mirror integrated to the InP-based active region, and to subsequent soldering on a SiC substrate. A single-mode output power of 77mW is obtained under CW-RT laser operation, limited by the pump power. Moreover thermal simulations and characterizations of the 1/2-VCSEL chip show that even higher power could be obtained at higher pumping levels, using a CVD diamond substrate. 相似文献
816.
Goldenstedt C Birer A Cathignol D Chesnais S El Bahri Z Massard C Taverdet JL Lafon C 《Ultrasonics sonochemistry》2008,15(5):808-814
PURPOSE: Delivering a drug close to the targeted cells improves its benefit versus risk ratio. A possible method for local drug delivery is to encapsulate the drug into solid microscopic carriers and to release it by ultrasound. The objective of this work was to use shock waves for delivering a molecule loaded in polymeric microcapsules. MATERIAL AND METHODS: Ethyl benzoate (EBZ) was encapsulated in spherical gelatin shells by complex coacervation. A piezocomposite shock wave generator (120 mm in diameter, focused at 97 mm, pulse length 1.4 micros) was used for sonicating the capsules and delivering the molecule. Shock parameters (acoustic pressure, number of shocks and shock repetition frequency) were varied in order to measure their influence on EBZ release. A cavitation-inhibitor liquid (Ablasonic) was then used to evaluate the role of cavitation in the capsule disruption. RESULTS: The measurements showed that the mean quantity of released EBZ was proportional to the acoustic pressure of the shock wave (r2 > 0.99), and increased with the number of applied shocks. Up to 88% of encapsulated EBZ could be released within 4 min only (240 shocks, 1 Hz). However, the quantity of released EBZ dropped at high shock rates (above 2Hz). Ultrasound imaging sequences showed that cavitation clouds might form, at high shock rates, along the acoustic axis making the exposure inefficient. Measurements done in Ablasonic showed that cavitation plays a major role in microcapsules disruption. CONCLUSIONS: In this study, we designed polymeric capsules that can be disrupted by shock waves. This type of microcapsule is theoretically a suitable vehicle for carrying hydrophobic drugs. Following these positive results, encapsulation of drugs is considered for further medical applications. 相似文献
817.
We report here the development of a new assay for the detection of ochratoxin A (OTA) based on the use of its dechlorinated
analogue, ochratoxin B (OTB), in a displacement immunoassay. OTB was immobilised on controlled-pore glass beads followed by
the binding of anti-OTA antibody, with anti-IgG antibody peroxidase conjugate used as a label. In this manner, an original
bio-sensing material was obtained. Upon incubation of this material with OTA, the toxin competes with OTB for the binding
sites of the anti-OTA antibodies and releases the antibody-tagged peroxidase complex into the solution. Compared to classic
competitive immunoassays, this newly developed displacement immunoassay presents a similar detection limit and assay time.
Moreover, the detection, based on the activity of the horseradish peroxidase, is performed for the first time in situ using
wine samples. 相似文献
818.
Bee-Ha Gan Xingguang Cai Sacha Javor Thilo Khler Jean-Louis Reymond 《Molecules (Basel, Switzerland)》2020,25(23)
There is an urgent need to develop new antibiotics against multidrug-resistant bacteria. Many antimicrobial peptides (AMPs) are active against such bacteria and often act by destabilizing membranes, a mechanism that can also be used to permeabilize bacteria to other antibiotics, resulting in synergistic effects. We recently showed that G3KL, an AMP with a multibranched dendritic topology of the peptide chain, permeabilizes the inner and outer membranes of Gram-negative bacteria including multidrug-resistant strains, leading to efficient bacterial killing. Here, we show that permeabilization of the outer and inner membranes of Pseudomonas aeruginosa by G3KL, initially detected using the DNA-binding fluorogenic dye propidium iodide (PI), also leads to a synergistic effect between G3KL and PI in this bacterium. We also identify a synergistic effect between G3KL and six different antibiotics against the Gram-negative Klebsiella pneumoniae, against which G3KL is inactive. 相似文献
819.
New properties for the one particle bridge function B(1)(r), which are necessary to the calculation of the excess chemical potential betamue), are derived for the hard sphere fluid. The method, which only requires the knowledge of the bridge function B(2)(r), is based on an investigation of the correlation function dependence on the Kirkwood charging parameter. In this framework, the unavoidable question of topological homotopy is addressed. As far as B(2)(r) is considered as exact, this work provides useful information on B(1)(r) in the well identified dynamical regimes of the hard sphere fluid. Signatures of the transitions between these regimes are identified on the trends of B(1)(r). This approach provides self-consistent results for betamue) that agree very well with simulation data. 相似文献
820.
Optimization of in-situ monolithic synthesis for immunopreconcentration in capillary 总被引:2,自引:0,他引:2
Poly(glycidyl methacrylate-co-ethylene dimethacrylate) monoliths have been synthetized in fused-silica capillary. The monomer mixture composition, initiation mode and porogen composition were optimized in order to provide a monolith with an homogeneous morphology and able to generate an electroosmotic flow via the incorporation of a small percentage of monomers possessing sulfonate group. Anti-ochratoxin A antibodies were immobilized through a single step on the epoxy groups leading to a miniaturized immunoextraction column. In order to evaluate the specificity of the analyte-antigen interaction on this immunosorbent, the retention of ochratoxin A was examined on this support but also on two complementary sorbents: one constituted by the non-bonded monolith and another one bonded with non-specific antibodies. Only the monolith bonded with anti-ochratoxin A antibodies lead to retention, showing the specificity of the interactions involved. This affinity phase based on a monolithic polymer support exhibits a high potential for specific preconcentration of small molecules. 相似文献