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排序方式: 共有398条查询结果,搜索用时 15 毫秒
151.
Dr. Xue Li Dr. Pablo Martinez‐Lozano Sinues Dr. Robert Dallmann Lukas Bregy Dr. Maija Hollmén Dr. Steven Proulx Prof. Steven A. Brown Prof. Michael Detmar Prof. Malcolm Kohler Prof. Renato Zenobi 《Angewandte Chemie (International ed. in English)》2015,54(27):7815-7818
Noninvasive, real‐time pharmacokinetic (PK) monitoring of ketamine, propofol, and valproic acid, and their metabolites was achieved in mice, using secondary electrospray ionization and high‐resolution mass spectrometry. The PK profile of a drug influences its efficacy and toxicity because it determines exposure time and levels. The antidepressant and anaesthetic ketamine (Ket) and four Ket metabolites were studied in detail and their PK was simultaneously determined following application of different sub‐anaesthetic doses of Ket. Bioavailability after oral administration vs. intraperitoneal injection was also investigated. In contrast to conventional studies that require many animals to be sacrificed even for low‐resolution PK curves, this novel approach yields real‐time PK curves with a hitherto unmatched time resolution (10 s), and none of the animals has to be sacrificed. This thus represents a major step forward not only in animal welfare, but also major cost and time savings. 相似文献
152.
Tia EV Adima AA Niamké SL Jean GA Martin T Lozano P Menut C 《Natural product communications》2011,6(8):1183-1188
Essential oils of aromatic plants with insecticidal properties are nowadays considered as alternative insecticides to protect cultures from attack by insect pest. The aims of the present work were to evaluate the toxicity of the essential oils vapors of two aromatic plants (Lippia multiflora Mold. and Aframomum latifolium K. Schum) against Bemisia tabaci and to characterize their chemical composition. The highest fumigant toxicity against B. tabaci adults was observed with the L. multiflora oil: by exposure to 0.4 microL/L air, the lethal time inducing 90% mortality (LT90) was below 2 hours for this essential oil whereas it reached 15 h in the case of the A. latifolium oil. Both oils were analyzed by GC-FID and GC-MS on two capillary columns. The oil of L. multiflora contained a majority of oxygenated terpenoids mainly represented by the two acyclic components linalool (46.6%) and (E)-nerolidol (16.5%); the oil of A. latifolium was dominated by hydrocarbonated terpenoids among them beta-pinene (51.6%) and beta-caryophyllene (12.3%) were the two major components. 相似文献
153.
Formation of thermally rearranged (TR) polybenzoxazoles: Effect of synthesis routes and polymer form
This study demonstrates that thermal treatment of ortho-hydroxy containing polyimides (HPIs) in the solid state certainly leads to the formation of polybenzoxazoles (PBOs). Thermal conversion protocol, including temperature and dwell time, and the form of the sample (film or powder) determine the rearrangement reaction rate of HPI into PBO. Thermal rearrangement kinetics seems to be faster for film samples rather than for powder ones. Also, mild thermal treatment conditions (i.e., low temperatures and short times) seem to result in negligible or low degrees of conversion to PBO. Moreover, synthetic routes of HPI do not alter in any way the thermal conversion pathway. These findings validate the widely reported imide-to-benzoxazole thermal rearrangement mechanism, and contradict the alternative rearrangement pathway, proposed recently, of HPI into poly(biphenylene bisimide) polymers. 相似文献
154.
A reactivity study of the most important elementary steps (propagation, intermolecular degradative transfer, and re‐initiation) in free‐radical polymerization of acrylfuranic systems, furfuryl acrylate (FA), and furfuryl methacrylate (FM), using the frontier molecular orbital theory is described. A qualitative explanation of reactivity trends of these steps for both systems is given based on absolute values of the SOMO/HOMO gap. The small difference between values of kp for FA and FM compared to that found for MA and MMA ( ) is justified semi‐quantitatively by applying a formulation for the change of energy in the transition state using second‐order perturbation theory.
155.
In this paper, linear production games are extended so that instead of assuming a linear production technology with fixed technological coefficients, the more general, non-parametric, DEA production technology is considered. Different organizations are assumed to possess their own technology and the cooperative game arises from the possibility of pooling their available inputs, collectively processing them and sharing the revenues. Two possibilities are considered: using a joint production technology that results from merging their respective technologies or each cooperating organization keeping its own technology. This gives rise to two different DEA production games, both of which are totally balanced and have a non-empty core. A simple way of computing a stable solution, using the optimal dual solution for the grand coalition, is presented. The full cooperation scenario clearly produces more benefits for the organizations involved although the implied technology sharing is not always possible. Examples of applications of the proposed approach are given. 相似文献
156.
Bosco García-Archilla Antonio J. Lozano Juan A. Mesa Federico Perea 《Journal of Heuristics》2013,19(2):399-422
This paper analyzes the solvability of a railway network design problem and its robust version. These problems are modeled as integer linear programming problems with binary variables, and their solutions provide topological railway networks maximizing the trip coverage in the presence of a competing mode, both assuming that the network works fine and that links can fail, respectively. Since these problems are computationally intractable for realistic sizes, GRASP heuristics are proposed for finding good feasible solutions. The results obtained in a computational experience indicate that our GRASP algorithms are suitable for railway network design problems. 相似文献
157.
We introduce thermometers to define the local temperature of an electronic system driven out-of-equilibrium by local ac fields. We discuss the behavior of the local temperature along the sample, showing that it exhibits spatial fluctuations following an oscillatory pattern. We show explicitly that the local temperature is the correct indicator for heat flow. 相似文献
158.
Arnaldi R Averbeck R Banicz K Castor J Chaurand B Cicalò C Colla A Cortese P Damjanovic S David A De Falco A Devaux A Drees A Ducroux L En'yo H Fargeix J Ferretti A Floris M Förster A Force P Guettet N Guichard A Gulkanian H Heuser JM Keil M Kluberg L Lourenço C Lozano J Manso F Masoni A Martins P Neves A Ohnishi H Oppedisano C Parracho P Pillot P Puddu G Radermacher E Ramalhete P Rosinsky P Scomparin E Seixas J Serci S Shahoyan R Sonderegger P Specht HJ Tieulent R Usai G Veenhof R 《Physical review letters》2006,96(16):162302
We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess of pairs is observed above the yield expected from neutral meson decays. The unprecedented sample size of 360,000 dimuons and the good mass resolution of about 2% allow us to isolate the excess by subtraction of the decay sources. The shape of the resulting mass spectrum is consistent with a dominant contribution from pi+pi- -->rho -->mu+mu- annihilation. The associated space-time averaged spectral function shows a strong broadening, but essentially no shift in mass. This may rule out theoretical models linking hadron masses directly to the chiral condensate. 相似文献
159.
Tamara Lozano‐Fernndez Marina Dobrovolskaia Toms Camacho frica Gonzlez‐Fernndez Rosana Simn‐Vzquez 《Particle & Particle Systems Characterization》2019,36(4)
Metal oxide nanoparticles (NPs) are increasingly used for different purposes, showing a potential risk on human health. The analysis of the interaction of these metal oxide NPs with blood components is a crucial step in the characterization of their biocompatibility, but information available of comparative studies with several doses and different metal oxide NPs is really scarce. In this study, six different metal oxide NPs (TiO2, CeO2, Al2O3, Y2O3, and two different types of ZnO NPs) at different concentrations are used, and their potential adverse effects on blood are determined. Both, prothrombin time (PT) and activated partial thromboplastin time (aPTT), are assessed to understand particle influence on the plasma coagulation cascade. Additional hematocompatibility tests include assessment of thrombin coagulation time, platelet aggregation, leukocyte procoagulant activity (PCA), hemolysis, and complement activation. The results demonstrate that only the ZnO and TiO2 NPs affect the coagulation cascade by increasing the aPTT in a dose‐dependent manner. Moreover, ZnO NPs increase PT, while TiO2 NPs induce a decrease in the PT. In addition to affecting coagulation time, ZnO NPs also induce platelet aggregation and leukocyte PCA. All tested metal oxide NPs do not affect hemolysis and complement activation. 相似文献
160.
Douglas L. Altshuler Marko Princevac Hansheng Pan Jesse Lozano 《Experiments in fluids》2009,46(5):835-846
The flow fields of slowly flying bats and faster-flying birds differ in that bats produce two vortex loops during each stroke,
one per wing, and birds produce a single vortex loop per stroke. In addition, the circulation at stroke transition approaches
zero in bats but remains strong in birds. It is unknown if these difference derive from fundamental differences in wing morphology
or are a consequence of flight speed. Here, we present an analysis of the horizontal flow field underneath hovering Anna’s
hummingbirds (Calypte anna) to describe the wake of a bird flying at zero forward velocity. We also consider how the hummingbird tail interacts with
the wake generated by the wings. High-speed image recording and analysis from three orthogonal perspectives revealed that
the wing tips reach peak velocities in the middle of each stroke and approach zero velocity at stroke transition. Hummingbirds
use complex tail kinematic patterns ranging from in phase to antiphase cycling with respect to the wings, covering several
phase shifted patterns. We employed particle image velocimetry to attain detailed horizontal flow measurements at three levels
with respect to the tail: in the tail, at the tail tip, and just below the tail. The velocity patterns underneath the wings
indicate that flow oscillates along the ventral–dorsal axis in response to the down- and up-strokes and that the sideways
flows with respect to the bird are consistently from the lateral to medial. The region around the tail is dominated by axial
flows in dorsal to ventral direction. We propose that these flows are generated by interaction between the wakes of the two
wings at the end of the upstroke, and that the tail actively defects flows to generate moments that contribute to pitch stability.
The flow fields images also revealed distinct vortex loops underneath each wing, which were generated during each stroke.
From these data, we propose a model for the primary flow structures of hummingbirds that more strongly resembles the bat model.
Thus, pairs of unconnected vortex loops may be shared features of different animals during hovering and slow forward flight. 相似文献