排序方式: 共有32条查询结果,搜索用时 15 毫秒
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Journal of Algebraic Combinatorics - It is well known that linear rank-metric codes give rise to q-polymatroids. Analogously to matroid theory, one may ask whether a given q-polymatroid is... 相似文献
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Dandurand Jany Samouillan Valérie Lacabanne Colette Pepe Antonietta Bochicchio Brigida 《Journal of Thermal Analysis and Calorimetry》2018,131(2):1323-1332
Journal of Thermal Analysis and Calorimetry - Elastin fibrillogenesis is conditioned by multiple self-assembly processes. Previous studies have evidenced the crucial influence of amino acid... 相似文献
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Valérie Samouillan Edouard Lamy Jany Dandurand Alexandrine Foucault-Bertaud Corinne Chareyre Colette Lacabanne Philippe Charpiot 《Journal of Non》2009,355(14-15):830-835
The thermal and dielectric properties of the elastin network were investigated in arteries cultured with physiological and pathological concentrations of homocysteine, an aminoacid responsible of histological impairments in human arteries. The glass transition of this amorphous protein was investigated by Differential Scanning Calorimetry (DSC). To explore the molecular dynamics of the elastin network in the nanometer range, we used Thermally Stimulated Currents (TSC), a dielectric technique running at low frequency and measuring the dipolar reorientations in proteins subjected to a static electrical field. Combining TSC and DSC experiments with determination of the activation parameters of relaxation times reveals the molecular mobility of the proteins. The major differences in the relaxation behavior of elastin between arteries cultured with physiological and pathological concentrations of homocysteine are discussed. 相似文献
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Josef Janyška 《Annali di Matematica Pura ed Applicata》1991,159(1):171-187
Summary Let p: EB be a fibred manifold. Then, we consider the sheaf
(E)=(B)P(E) of (local) projectable tangent valued forms on E, where (B) is the sheaf of (local) differential forms on B andP(E) is the sheaf of (local) projectable vector fields on E. The Frölicher-Nijenhuis bracket makes
(E) to be a sheaf of graded Lie algebras [18]. In this paper we study all natural R -bilinear operations on
(E) which are of Frölicher-Nijenhuis type. By using the analytical method of [16], we prove that there is a three-parameter family of such operators on
(E). As a consequence, we obtain a result on the unicity of the covariant differential of tangent valued forms and of the curvature associated with a given connection on E. All manifolds and mappings are assumed to be infinitely differentiable.This paper has been written during the author's visit at the Institute of Applied Mathematics «Giovanni Sansone». Florence, Italy. The author would like to thank ProfessorMarco Modugno for his kind hospitality and for stimulating discussions. 相似文献
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Gloria Fernandez-LorenteJose M Palomo Jany CoccaCesar Mateo Paola MoroMarco Terreni Roberto Fernandez-Lafuente Jose M Guisan 《Tetrahedron》2003,59(30):5705-5711
Purified lipases (via interfacial activation on hydrophobic supports) from different microbial extracts have been evaluated in the regio-selective hydrolysis of peracetylated sugars (peracetylated glucose, ribose and sucrose). Among the enzymes tested, lipases from Candida rugosa (CRL) and from Pseudomonas fluorescens (PFL) exhibited the best properties in these reactions.Then, we have prepared two different immobilized lipase preparations obtained by interfacial activation on hydrophobic supports or by covalent attachment on glutaraldehyde agarose. Interfacially activated lipases exhibited a higher activity than covalently attached enzymes (even by a 100-fold factor), giving the higher yields of mono deacetylated sugars (in some instances by more than a threefold factor) in short reaction times. In the hydrolysis of 1,2,3,5-tetra-O-acetyl-β-d-ribofuranose catalyzed by PFL adsorbed on octyl agarosa, hydrolyzed mainly the 3 position (30% of yield) while the CRL gave the hydrolysis only in position 5 (about 50% of yield).Depending on the enzyme immobilized preparation, we have been able also to obtain selective hydrolysis of 1,2,3,4,6-penta-O-acetyl-α/β-d-glucopyranose obtaining a free hydroxyl group in position 1, 4 or 6. Moreover, selective hydrolysis in the 4′ position of peracetylated sucrose was achieved when the hydrolysis is performed with CRL immobilized on octyl-agarose (yield was 77%). 相似文献
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This paper is aimed at introducing an algebraic model for physical scales and units of measurement. This goal is achieved
by means of the concept of “positive space” and its rational powers. Positive spaces are “semi-vector spaces” on which the
group of positive real numbers acts freely and transitively through the scalar multiplication. Their tensor multiplication
with vector spaces yields “scaled spaces” that are suitable to describe spaces with physical dimensions mathematically. We
also deal with scales regarded as fields over a given background (e.g., spacetime). 相似文献
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In this paper we introduce the general covariant derivatives of vertical-valued tensor fields with respect to a general connection on a fibered manifold and a classical connection on the base. We prove that the general covariant derivatives satisfy the general Ricci and the general Bianchi identities. 相似文献
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Josef Janyška 《Central European Journal of Mathematics》2005,3(2):294-308
We generalize reduction theorems for classical connections to operators with values in k-th order natural bundles. Using the 2nd order valued reduction theorems we classify all (0,2)-tensor fields on the cotangent
bundle of a manifold with a linear (non-symmetric) connection.
This paper has been supported by the Grant Agency of the Czech Republic under the Project number GA 201/02/0225. 相似文献