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排序方式: 共有201条查询结果,搜索用时 46 毫秒
1.
In this article, we have summarized the recent important results related to the electrochemical detection of vesicular exocytosis by amperometry with microelectrodes over the past three years. In this fascinating scientific field that began 40 years ago, the historical carbon fiber amperometry method still continues to be used to address biological questions by the pioneered groups of the field but also by other research groups thus showing this has become an indispensable routine technique for analyzing exocytosis. Furthermore, new methodologies (coupling with fluorescence, use of nanoelectrodes, microarrays) have blossomed and demonstrated how new analytical methods could be built to push back the limits of the initial technique. 相似文献
2.
Alembert T. Tchinda Simplice R. Mouokeu Rosalie A.N. Ngono Madeleine R.E. Ebelle Aristide L.K. Mokale Diane K. Nono 《Natural product research》2015,29(21):1990-1994
A phytochemical investigation of the whole plant of Crassocephalum bauchiense Huch. resulted in the isolation of a new clerodane diterpenoid, ent-2β,18,19-trihydroxycleroda-3,13-dien-16,15-olide (1), together with two known flavonoids 3′,5-dihydroxy-4′,5′,6,7,8-pentamethoxyflavone (2) and 4′,5-dihydroxy-3′,5′,6,7,8-pentamethoxyflavone (3). The compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. Compound 2 showed weak activity (IC50 = 10.1 g/mL) whilst compounds 1 and 3 were inactive. The structures of the compounds were elucidated by using detailed spectral analyses, especially 1H and 13C NMR, 1H–1H COSY, NOESY, HMBC and HR-ESI-MS. 相似文献
3.
Mihail I. Petrov Sergey V. Sukhov Andrey A. Bogdanov Alexander S. Shalin Aristide Dogariu 《Laser \u0026amp; Photonics Reviews》2016,10(1):116-122
We demonstrate both analytically and numerically the existence of optical pulling forces acting on particles located near plasmonic interfaces. Two main factors contribute to the appearance of this negative recoil force. The interference between the incident and reflected waves induces a rotating dipole with an asymmetric scattering pattern, while the directional excitation of surface plasmon polaritons (SPPs) enhances the linear momentum of scattered light. The strongly asymmetric SPP excitation is determined by spin–orbit coupling of the rotating dipole and surface plasmon polariton. As a result of the total momentum conservation, the force acting on the particle points in a direction opposite to the incident wave propagation. We derive analytical expressions for the force acting on dipolar particles placed in the proximity of plasmonic surfaces. Analytical expressions for this pulling force are derived within the dipole approximation and are in excellent agreement with results of electromagnetic numerical calculations. The forces acting on larger particles are analyzed numerically, beyond the dipole approximation.
4.
5.
Monitoring and Quantifying the Passive Transport of Molecules Through Patch–Clamp Suspended Real and Model Cell Membranes 下载免费PDF全文
Dr. Pierluca Messina Dr. Frédéric Lemaître Prof. François Huet Dr. Kieu An Ngo Dr. Vincent Vivier Prof. Eric Labbé Dr. Olivier Buriez Prof. Christian Amatore 《Angewandte Chemie (International ed. in English)》2014,53(12):3192-3196
Transport of active molecules across biological membranes is a central issue for the success of many pharmaceutical strategies. Herein, we combine the patch–clamp principle with amperometric detection for monitoring fluxes of redox‐tagged molecular species across a suspended membrane patched from a macrophage. Solvent‐ and protein‐free lipid bilayers (DPhPC, DOPC, DOPG) patched from single‐wall GUV have been thoroughly investigated and the corresponding fluxes measurements quantified. The quality of the patches and their proper sealing were successfully characterized by electrochemical impedance spectroscopy. This procedure appears versatile and perfectly adequate to allow the investigation of transport and quantification of the transport properties through direct measurement of the coefficients of partition and diffusion of the compound in the membrane, thus offering insight on such important biological and pharmacological issues. 相似文献
6.
This paper presents a unified exact method for solving an extended model of the well-known Capacitated Vehicle Routing Problem
(CVRP), called the Heterogenous Vehicle Routing Problem (HVRP), where a mixed fleet of vehicles having different capacities,
routing and fixed costs is used to supply a set of customers. The HVRP model considered in this paper contains as special
cases: the Single Depot CVRP, all variants of the HVRP presented in the literature, the Site-Dependent Vehicle Routing Problem
(SDVRP) and the Multi-Depot Vehicle Routing Problem (MDVRP). This paper presents an exact algorithm for the HVRP based on
the set partitioning formulation. The exact algorithm uses three types of bounding procedures based on the LP-relaxation and
on the Lagrangean relaxation of the mathematical formulation. The bounding procedures allow to reduce the number of variables
of the formulation so that the resulting problem can be solved by an integer linear programming solver. Extensive computational
results over the main instances from the literature of the different variants of HVRPs, SDVRP and MDVRP show that the proposed
lower bound is superior to the ones presented in the literature and that the exact algorithm can solve, for the first time
ever, several test instances of all problem types considered.
相似文献
7.
Tanese D Solnyshkov DD Amo A Ferrier L Bernet-Rollande E Wertz E Sagnes I Lemaître A Senellart P Malpuech G Bloch J 《Physical review letters》2012,108(3):036405
We investigate the effect of disorder on the propagation of one-dimensional polariton condensates in semiconductor microcavities. We observe a strong suppression of the backscattering produced by the imperfections of the structure when increasing the condensate density. This suppression occurs in the supersonic regime and is simultaneous to the onset of parametric instabilities which enable the "hopping" of the condensate through the disorder. Our results evidence a new mechanism for the strong scattering reduction of polaritons at high speeds. 相似文献
8.
We show that under some natural ergodicity assumptions, extensions given by Rokhlin cocycles lift the multiplier property
if the associated locally compact group extension has only countably many L∞-eigenvalues. We make use of some analogs of basic results from the theory of finite-rank modules associated to an extension
of measure-preserving systems in the setting of a non-singular base. 相似文献
9.
For each monothetic unitary group without proper co-compact subgroups, we show the existence of a compact semitopological
semigroup (affine) compactification in which the set of idempotents is not closed answering a question of Berglund. 相似文献
10.
We develop a general study of ergodic properties of extensions of measure preserving dynamical systems. These extensions are
given by cocycles (called here Rokhlin cocycles) taking values in the group of automorphisms of a measure space which represents
the fibers. We use two different approaches in order to study ergodic properties of such extensions. The first approach is
based on properties of mildly mixing group actions and the notion of complementary algebra. The second approach is based on
spectral theory of unitary representations of locally compact Abelian groups and the theory of cocycles taking values in such
groups. Finally, we examine the structure of self-joinings of extensions.
We partially answer a question of Rudolph on lifting mixing (and multiple mixing) property to extensions and answer negatively
a question of Robinson on lifting Bernoulli property. We also shed new light on some earlier results of Glasner and Weiss
on the class of automorphisms disjoint from all weakly mixing transformations.
Answering a question asked by Thouvenot we establish a relative version of the Foiaş—Stratila theorem on Gaussian—Kronecker
dynamical systems.
Research partially supported by KBN grant 2 P03A 002 14 (1998). 相似文献