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981.
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Journal of High Energy Physics - The coset Sp(2, ℝ)/U(1) is parametrized by two real scalar fields. We generalize the formalism of auxiliary tensor (bispinor) fields in U(1) self-dual...  相似文献   
984.
In this paper, we develop a new class of bivariate counting processes that have ‘marginal regularity’ property. But, the ‘pooled processes’ in the developed class of bivariate counting processes are not regular. Therefore, the proposed class of processes allows simultaneous occurrences of two types of events, which can be applicable in practical modeling of counting events. Initially, some basic properties of the new class of bivariate counting processes will be discussed. Based on the obtained properties, the joint distributions of the numbers of events in time intervals will be derived and the dependence structure of the bivariate process will be discussed. Furthermore, the marginal and conditional processes will be studied. The application of the proposed bivariate counting process to a shock model will also be considered. In addition, the generalization to the multivariate counting processes will be discussed briefly.  相似文献   
985.
The preparation, characterization, and properties of the new thermoplastic vulcanizate (TPV)/organoclay nanocomposites are reported in this article. The nanocomposites were prepared by the melt intercalation method. The organoclay was first treated with glycidyl methacrylate, which acts as a swelling agent for organoclays, as well as a grafting agent for TPV (in the presence of dicumyl peroxide) during the melt mixing. The nanocomposite was intercalated, as evidenced by X‐ray diffraction. The tensile modulus of the 5% TPV/organoclay nanocomposite was higher than that of the 20% talc‐filled microcomposite. The storage modulus of the nanocomposite was higher than that of the pristine TPV. The most important observation is obtained from dynamic mechanical analysis, which reveals that the glass‐transition temperature of the polypropylene phase of the nanocomposite increases (as compared to virgin TPV), whereas the ethylene–propylene–diene monomer phase remains almost the same. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2900–2908, 2004  相似文献   
986.
987.
To experimentally clarify a possible stereostructure-activity relationship proposed for H2-receptor antagonists, three 5-aminophenylimidazoles (1, 2 and 3), in which respective amino groups are located on the ortho, meta and para positions of the benzene ring, were synthesized and examined for their conformational characteristics using X-ray diffraction and proton nuclear magnetic resonance (1H-NMR) methods, and for antiulcer activities on rats and H2-receptor antagonist activities in guinea pig. The ortho isomer 1, which preferentially formed an intramolecular N-H (amino)...N (imidazole) hydrogen bond, showed the highest antiulcer activity with half the efficacy of cimetidine. On the other hand, none of 1, 2 and 3 showed significant H2-receptor antagonist activity. Based on these results, the conformational characteristic for the exhibition of antiulcer activity has been discussed.  相似文献   
988.
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990.
Angiotensin converting enzyme (ACE) plays an important role in the physiology of vasculature, blood pressure and inflammation. ACE gene, known to have insertion/deletion (I/D) polymorphism, has been widely investigated in its relation with cardiovascular and neurodegenerative diseases and longevity. ACE gene polymorphism in an inflammation associated osteoarthritis (OA) patients is not known. Here we have investigated ACE gene polymorphism in 142 Korean primary knee OA patients and 135 healthy volunteers to establish any clinical correlates between ACE polymorphism and knee osteoarthritis. Clinical parameters such as disease onset age, Kellgren-Lawrence grade and Lequesne's functional index provided additional analysis of the relationship of ACE polymorphism and clinical features of OA. Early onset OA showed significantly higher allele frequency and carriage rate of I than late onset OA. Radiographically severe and functionally poor OA showed higher carriage rate of I allele than radiographically mild and functionally good OA, respectively. This study first reports ACE gene polymorphism to be a risk factor for early onset, severe form primary knee OA.  相似文献   
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