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41.
Nicotinic acetylcholine receptors (nAChRs) are widely expressed in or on various cell types and have diverse functions. In immune cells nAChRs regulate proliferation, differentiation and cytokine release. Specifically, activation of the α7 nAChR reduces inflammation as part of the cholinergic anti-inflammatory pathway. Here we review numerous effects of α7 nAChR activation on immune cell function and differentiation. Further, we also describe evidence implicating this receptor and its chaperone RIC-3 in diseases of the central nervous system and in neuroinflammation, focusing on multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Deregulated neuroinflammation due to dysfunction of α7 nAChR provides one explanation for involvement of this receptor and of RIC-3 in neurodegenerative diseases. In this review, we also provide evidence implicating α7 nAChRs and RIC-3 in neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) involving neuroinflammation. Besides, we will describe the therapeutic implications of activating the cholinergic anti-inflammatory pathway for diseases involving neuroinflammation.  相似文献   
42.
Many physical phenomena develop singular, or nearly singular behavior in localized regions, e.g. boundary layers or blowup solutions. Using uniform grids for such problems becomes computationally prohibitive as the solution approaches singularity. Ren and Wang developed a semi-static adaptive grid method [W. Ren, X.P. Wang, An iterative grid redistribution method for singular problems in multiple dimensions, J. Comput. Phys. 159 (2000) 246–273] for the solution of these problems, known as the iterative grid redistribution (IGR) method. In this study we develop a theoretical basis for semi-static adaptive grid method for singular problems. Based on this theory, we obtain the key result of this study – a methodology for designing robust weight functionals which ensures grid resolution in the singular region, as well as control of the maximal grid spacing in the outer region. Using this methodology, we introduce a semi-static adaptive grid method, which does not involve an iterative procedure for grid redistribution, as in the IGR method. We demonstrate the efficacy of this method with numerical examples of solutions which localize by more than nine orders of magnitude.  相似文献   
43.
We introduce a new method to derive lower bounds on randomized and quantum communication complexity. Our method is based on factorization norms, a notion from Banach Space theory. This approach gives us access to several powerful tools from this area such as normed spaces duality and Grothendiek's inequality. This extends the arsenal of methods for deriving lower bounds in communication complexity. As we show, our method subsumes most of the previously known general approaches to lower bounds on communication complexity. Moreover, we extend all (but one) of these lower bounds to the realm of quantum communication complexity with entanglement. Our results also shed some light on the question how much communication can be saved by using entanglement. It is known that entanglement can save one of every two qubits, and examples for which this is tight are also known. It follows from our results that this bound on the saving in communication is tight almost always. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009  相似文献   
44.
A convergent and highly stereoselective total synthesis of the Z-isomer of cytospolide E has been achieved via Evan’s aldol reaction, Sharpless kinetic resolution and RCM cyclisation.  相似文献   
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The model of zero-knowledge multi-prover interactive proofs was introduced by Ben-Or, Goldwasser, Kilian and Wigderson in [4]. A major open problem associated with this model is whether NP problems can be proven by one-round, two-prover, zero-knowledge protocols with exponentially small error probability (e.g. via parallel executions). A positive answer was claimed by Fortnow, Rompel and Sipser in [12], but its proof was later shown to be flawed by Fortnow who demonstrated that the probability of cheating inn independent parallel rounds can be much higher than the probability of cheating inn independent sequential rounds (with exponential ratio between them). In this paper we solve this problem: We show a new one-round two-prover interactive proof for Graph Hamiltonicity, we prove that it is complete, sound and perfect zeroknowledge, and thus every problem in NP has a one-round two-prover interactive proof which is perfectly zero knowledge under no cryptographic assumptions. The main difficulty is in proving the soundness of our parallel protocol namely, proving that the probability of cheating in this one-round protocol is upper bounded by some exponentially low threshold. We prove that this probability is at most 1/2 n/9 (wheren is the number of parallel rounds), by translating the soundness problem into some extremal combinatorial problem, and then solving this new problem.  相似文献   
48.
The exchange currents of Ag/AgNO_3-NH_3 electrode systems were measured by using radiotrcer method.The magnitude of exchange currents was obtained to be of the order 10~(-7) A. cm~(-2) in solutions with various concentrations of Ag~+(Ⅰ). The data show that the exchange currents decrease with reduction in Ag~+ (Ⅰ) concen- trations.However the difference of exchange currents is not significant.It is in coincidance with the assumption that in very low overpotential region the surface diffusion of adatom is the rate determining step.The experimental conditions that must be fulfilled in order to ensure successful application of this method were also discussed.  相似文献   
49.
Miscibility enhancement of ionomer/ionomer and ionomer/polymeric acid systems is studied on the polymer pairs of poly(styrene-co-tetramethyl ammonium styrenesulfonate)/poly(ethyl acrylate-co-N-methyl-4-vinylpyridinium iodide) and poly(styrene-co-styrenesulfonic acid)/poly(ethyl acrylate-co-N-methyl-4-vinylpyridinium iodide). NMR and dynamic mechanical results show that in these blends direct macroion–macroion interaction can be achieved with the elimination of microcounterions from the polymer chains. Ion-ion attraction leads to a miscibility enhancement comparable to that of the previously reported proton transfer blends; a miscible blend is obtained with ca. 5 mol% of ions in the polymers.  相似文献   
50.
We investigate the solubilization of 2-nitrodiphenylamine, a hydrophobic but polar dye molecule, in aqueous solutions of polystyrene(310)-b-poly(acrylic acid)(47) micelles. The solubilization capacity of the micelles, which consist of a polystyrene core and poly(acrylic acid) corona, and the micelle-water partition coefficient are evaluated as a function of the solubilizate concentration. The solubilization isotherm shows a nonlinear behavior, and the partition coefficient, instead of being constant, is strongly dependent on the dye concentration. These results are explained by treating solubilization as a binding process, and by fitting the data to a Langmuir adsorption model. In addition, we examine the locus of solubilization of 2-nitrodiphenylamine using its solvatochromic properties and solubility in model solvents, and we identify the micellar interface as the solubilization site. Confirmatory studies, including the dependence of solubilization on the interfacial area of the aggregates, the role of the poly(acrylic acid) corona chains in stabilizing the solubilized molecules, and the effect of the solubilizate structure on the extent of incorporation, were also conducted. The results, consistent with surface localization, show that solubilization is dependent on the interfacial area of the aggregates, and on the affinity of the solubilizate for the micellar interface.  相似文献   
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