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991.
We study the Hall effect in a system of weakly coupled Luttinger Liquid chains, using a Memory function approach to compute
the Hall constant in the presence of umklapp scattering along the chains. In this approximation, the Hall constant decomposes
into two terms: a high-frequency term and a Memory function term. For the case of zero umklapp scattering, where the Memory
function vanishes, the Hall constant is simply the band value, in agreement with former results in a similar model with no
dissipation along the chains. With umklapp scattering along the chains, we find a power-law temperature dependance of the
Hall constant. We discuss the applications to quasi 1D organic conductors at high temperatures. 相似文献
992.
P. Lafitte Lionel Valenti† Lydia Casciani† Thierry Hoarau E. Lomonte† Frédéric Maccario† Jean-François Nicola 《International journal of cosmetic science》2009,31(3):243-243
Citation: IFSCC Magazine , 11 (2008) (2) 105–112
Abstract: A novel photoprotective ingredient with anti-oxidant and electrophilic scavenging properties was designed. A structure–activity relationship study was conducted in order to optimize its bioavailability, specifically its ability to reach deep layers of the skin that may be affected by ultraviolet radiation-induced oxidative stress. A particular characteristic of this compound is its ability to release taurine upon reaction with some reactive oxygen species. In situ taurine formation may contribute to photoprotection. Preliminary in vitro experiments provide some evidence for effective protection against UVA-induced oxidative stress. Scavenging of the electrophilic species 4-hydroxynonenal, a highly cytotoxic end product of membrane lipid peroxidation, seems to be 2-oxo-1,3-thiazolidine major photoprotective mechanism.
Keywords: antioxidant, electrophilic species scavenging, photoprotection, structure-activity relationship, taurine
Paper presented at the IFSCC Conference 2007, Amsterdam, The Netherlands 相似文献
Abstract: A novel photoprotective ingredient with anti-oxidant and electrophilic scavenging properties was designed. A structure–activity relationship study was conducted in order to optimize its bioavailability, specifically its ability to reach deep layers of the skin that may be affected by ultraviolet radiation-induced oxidative stress. A particular characteristic of this compound is its ability to release taurine upon reaction with some reactive oxygen species. In situ taurine formation may contribute to photoprotection. Preliminary in vitro experiments provide some evidence for effective protection against UVA-induced oxidative stress. Scavenging of the electrophilic species 4-hydroxynonenal, a highly cytotoxic end product of membrane lipid peroxidation, seems to be 2-oxo-1,3-thiazolidine major photoprotective mechanism.
Keywords: antioxidant, electrophilic species scavenging, photoprotection, structure-activity relationship, taurine
Paper presented at the IFSCC Conference 2007, Amsterdam, The Netherlands 相似文献
993.
Tarek Alouane Hlne Rimbert Jrg Bormann Gisela A. Gonzlez-Montiel Sandra Loesgen Wilhelm Schfer Michael Freitag Thierry Langin Ludovic Bonhomme 《International journal of molecular sciences》2021,22(12)
Fusarium graminearum, the primary cause of Fusarium head blight (FHB) in small-grain cereals, demonstrates remarkably variable levels of aggressiveness in its host, producing different infection dynamics and contrasted symptom severity. While the secreted proteins, including effectors, are thought to be one of the essential components of aggressiveness, our knowledge of the intra-species genomic diversity of F. graminearum is still limited. In this work, we sequenced eight European F. graminearum strains of contrasting aggressiveness to characterize their respective genome structure, their gene content and to delineate their specificities. By combining the available sequences of 12 other F. graminearum strains, we outlined a reference pangenome that expands the repertoire of the known genes in the reference PH-1 genome by 32%, including nearly 21,000 non-redundant sequences and gathering a common base of 9250 conserved core-genes. More than 1000 genes with high non-synonymous mutation rates may be under diverse selection, especially regarding the trichothecene biosynthesis gene cluster. About 900 secreted protein clusters (SPCs) have been described. Mostly localized in the fast sub-genome of F. graminearum supposed to evolve rapidly to promote adaptation and rapid responses to the host’s infection, these SPCs gather a range of putative proteinaceous effectors systematically found in the core secretome, with the chloroplast and the plant nucleus as the main predicted targets in the host cell. This work describes new knowledge on the intra-species diversity in F. graminearum and emphasizes putative determinants of aggressiveness, providing a wealth of new candidate genes potentially involved in the Fusarium head blight disease. 相似文献
994.
Haifeng Xie Thierry J Chaussalet Peter H Millard 《IEEE transactions on information technology in biomedicine》2006,10(3):512-518
Understanding the pattern of length of stay in institutional long-term care has important practical implications in the management of long-term care. Furthermore, residents' attributes are believed to have significant effects on these patterns. In this paper, we present a model-based approach to extract, from a routinely gathered administrative social care dataset, high-level length-of-stay patterns of residents in long-term care. This approach extends previous work by the authors to incorporate residents' features. Two applications using data provided by a local authority in England are presented to demonstrate the potential use of this approach. 相似文献
995.
Polynomial chaos expansion for sensitivity analysis 总被引:3,自引:0,他引:3
In this paper, the computation of Sobol's sensitivity indices from the polynomial chaos expansion of a model output involving uncertain inputs is investigated. It is shown that when the model output is smooth with regards to the inputs, a spectral convergence of the computed sensitivity indices is achieved. However, even for smooth outputs the method is limited to a moderate number of inputs, say 10-20, as it becomes computationally too demanding to reach the convergence domain. Alternative methods (such as sampling strategies) are then more attractive. The method is also challenged when the output is non-smooth even when the number of inputs is limited. 相似文献
996.
Thierry Coquand Henri Lombardi Peter Schuster 《Annals of Mathematics and Artificial Intelligence》2009,56(3-4):339-360
We give a point-free definition of a Grothendieck scheme whose underlying topological space is spectral. Affine schemes aside, the prime examples are the projective spectrum of a graded ring and the space of valuations corresponding to an abstract nonsingular curve. With the appropriate notion of a morphism between spectral schemes, elementary proofs of the universal properties become possible. “What would have happened if topologies without points had been discovered before topologies with points, or if Grothendieck had known the theory of distributive lattices?” Gian-Carlo Rota, Indiscrete Thoughts. Birkhäuser (1997), p. 220 相似文献
997.
A new SURE approach to image denoising: interscale orthonormal wavelet thresholding. 总被引:2,自引:0,他引:2
This paper introduces a new approach to orthonormal wavelet image denoising. Instead of postulating a statistical model for the wavelet coefficients, we directly parametrize the denoising process as a sum of elementary nonlinear processes with unknown weights. We then minimize an estimate of the mean square error between the clean image and the denoised one. The key point is that we have at our disposal a very accurate, statistically unbiased, MSE estimate--Stein's unbiased risk estimate--that depends on the noisy image alone, not on the clean one. Like the MSE, this estimate is quadratic in the unknown weights, and its minimization amounts to solving a linear system of equations. The existence of this a priori estimate makes it unnecessary to devise a specific statistical model for the wavelet coefficients. Instead, and contrary to the custom in the literature, these coefficients are not considered random anymore. We describe an interscale orthonormal wavelet thresholding algorithm based on this new approach and show its near-optimal performance--both regarding quality and CPU requirement--by comparing it with the results of three state-of-the-art nonredundant denoising algorithms on a large set of test images. An interesting fallout of this study is the development of a new, group-delay-based, parent-child prediction in a wavelet dyadic tree. 相似文献
998.
999.
Thierry Alex Mara 《Reliability Engineering & System Safety》2009,94(8):1274-1281
This paper deals with the sensitivity analysis method named Fourier amplitude sensitivity test (FAST). This method is known to be very robust for the computation of global sensitivity indices but their computational cost remains prohibitive for complex and large dimensional models. Recent developments in the implementation of FAST by use of the random balance designs (RBD) technique have allowed significant reduction of the computational cost. The method is now called RBD-FAST. The drawback of this improvement is that only individual first-order sensitivity indices can be computed. In this article, an extension of RBD is derived for the estimation of any global sensitivity indices of individual factor or group of factors. Several tests are proposed to compare the performances of classical FAST and RBD-FAST. 相似文献
1000.
Motion planning for cooperative unicycle-type mobile robots with limited sensing ranges: A distributed receding horizon approach 总被引:1,自引:0,他引:1
This paper presents a decentralized motion planner for a team of nonholonomic mobile robots subject to constraints imposed by sensors and the communication network. The motion planning scheme consists of decentralized receding horizon planners that reside on each vehicle to achieve coordination among flocking agents. The advantage of the proposed algorithm is that each vehicle only requires local knowledge of its neighboring vehicles. The main requirement for designing an optimal conflict-free trajectory in a decentralized way is that each robot does not deviate too far from its presumed trajectory designed without taking the coupling constraints into account. A comparative study between the proposed algorithm and other existing algorithms is provided in order to show the advantages, especially in terms of computing time. Finally, experiments are performed on a team of three mobile robots to demonstrate the validity of the proposed approach. 相似文献