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排序方式: 共有716条查询结果,搜索用时 15 毫秒
1.
Platelet aggregation is known to be inhibited by ethanol, and this has been suggested to be one of the attenuating effects
of ethanol in cardiovascular disease. Recent studies have implicated an inhibition of phospholipase A2 induced arachidonic acid release, since the production of prostanoids that are formed from arachidonic acid and are involved
in the aggregation process has been shown to be diminished by ethanol. Phospholipase A2 is found in platelets in both a cytosolic form, from where it may translocate to the plasma membrane to release arachidonic
acid, and in a secretory form which is released extracellularly upon activition. In the present study, the effect of ethanol
on the secretion of phospholipase A2 and on its activity was determined. It was found that ethanol inhibited trast, the activity of the cytosolic form of phospholipase
A2 was inhibited by ethanol. 相似文献
2.
The reticular lamina creates an ion barrier, withstands mechanical stress in the organ of Corti and is able to maintain its integrity during and after severe hair cell loss. Tight junctions maintain the ionic gradient whereas adherens junctions and the cytoskeleton are responsible for the integrity and mechanical resistance of tissues. In this study we used immunofluorescence and electron microscopy to examine the distribution of proteins of tight junctions (cingulin), adherens junctions (E-cadherin, alpha- and beta-catenin) and the cytoskeleton (actin, cytokeratin and tubulin) in whole-mounts of the normal and ototoxically damaged organ of Corti. In normal ears the proteins of adherens junctions were found in all cell types of the reticular lamina. We now demonstrate that all cells forming the reticular lamina partially overlap each other organizing extensive cell contacts with a complex three-dimensional shape. During scar formation, the tight junctions as well as adherens junctions between hair and supporting cells appeared in two distinct focal planes, which could help to preserve the ionic barrier and tissue integrity during hair cell degeneration. During scar formation all cytoskeletal structures in the reticular lamina were reorganized in a specific spatio-temporal pattern. We present a three-dimensional model of cell contact organization in the reticular lamina of normal ears and during scar formation. 相似文献
3.
Raphael M. Munavu 《Journal of the American Oil Chemists' Society》1983,60(9):1653-1653
Seed kernels ofCalodendrum capense (L.f.) Thunb. yielded 60% of a light yellow oil which had the following fatty acid composition: 23.8% palmitic, 4.5% stearic,
33.7% oleic, 35.6% linoleic, 1.4% linolenic and 1.0% arachidic. Myristic and behenic acids were present in trace amounts,
and the kernel cake contained 37.6% crude protein. 相似文献
4.
5.
Dragomir B. Bukur Snehal A. Patel Raphael Matheo 《Chemical Engineering Communications》1987,60(1):63-78
Gas hold-up and Sauter mean bubble diameter measurements were made in a 0.051 m diameter by 3 m long glass bubble column in the system, nitrogen-molten wax, with three different waxes (paraffin wax FT-300, Sasol's Arge wax and Mobil's reactor wax). Paraffin wax has a tendency to foam and gas hold-up is a strong function of gas distributor type, temperature and start-up procedure, whereas the reactor waxes do not foam and are much less affected by these variables, In experiments at 265°C with a 1.85 mm single hole orifice plate distributor the gas hold-ups were nearly the same for all three waxes. However, significant differences in Sauter mean bubble diameters were obtained in experiments with different waxes; FT-300 wax produced the smallest Sauter mean bubble diameters whereas Mobil's reactor wax produced the largest bubbles. Addition of 1-octadecanol and octadecanoic acid (up to 10wt%) to the FT-300 paraffin wax caused an increase in gas hold-up and a delay in the foam break-up in runs at 265°C with the 1.85 mm orifice plate distributor. 相似文献
6.
Analysis of the hornet’s hemolymph revealed the presence of C16 and C18 fatty acids (70%), which were accompanied by minor quantities (ranging from 0.1% to 0.6%) of the following acids: C10∶0, C11∶0, C12∶0, C13∶0, C14∶0, C15∶0, C16∶0, and C17∶0. The hemolymph of the queen larvae contained more C18∶1 than the hemolymph of the worker larvae, and the percentage of C16∶1 was higher in the fat body and the midgut than in the hemolymph. The significance of these results is discussed. 相似文献
7.
8.
Password-authenticated key exchange (PAKE) protocols allow parties to share secret keys in an authentic manner based on an easily memorizable password. Recently, Lu and Cao proposed a three-party password-authenticated key exchange protocol, so called S-3PAKE, based on ideas of the Abdalla and Pointcheval two-party SPAKE extended to three parties. S-3PAKE can be seen to have a structure alternative to that of another three-party PAKE protocol (3PAKE) by Abdalla and Pointcheval. Furthermore, a simple improvement to S-3PAKE was proposed very recently by Chung and Ku to resist the kind of attacks that applied to earlier versions of 3PAKE. In this paper, we show that S-3PAKE falls to unknown key-share attacks by any other client, and undetectable online dictionary attacks by any adversary. The latter attack equally applies to the recently improved S-3PAKE. Indeed, the provable security approach should be taken when designing PAKEs; and furthermore our results highlight that extra cautions still be exercised when defining models and constructing proofs in this direction. 相似文献
9.
Since RFID tags are ubiquitous and at times even oblivious to the human user, all modern RFID protocols are designed to resist tracking so that the location privacy of the human RFID user is not violated. Another design criterion for RFIDs is the low computational effort required for tags, in view that most tags are passive devices that derive power from an RFID reader's signals. Along this vein, a class of ultralightweight RFID authentication protocols has been designed, which uses only the most basic bitwise and arithmetic operations like exclusive-OR, OR, addition, rotation, and so forth. In this paper, we analyze the security of the SASI protocol, a recently proposed ultralightweight RFID protocol with better claimed security than earlier protocols. We show that SASI does not achieve resistance to tracking, which is one of its design objectives. 相似文献
10.
Sunil Kumar Richard J. Pippy Erdem Acar Nam H. Kim Raphael T. Haftka 《Structural and Multidisciplinary Optimization》2009,38(6):613-626
Probabilistic structural design deals with uncertainties in response (e.g. stresses) and capacity (e.g. failure stresses).
The calculation of the structural response is typically expensive (e.g., finite element simulations), while the capacity is
usually available from tests. Furthermore, the random variables that influence response and capacity are often disjoint. In
previous work we have shown that this disjoint property can be used to reduce the cost of obtaining the probability of failure
via Monte Carlo simulations. In this paper we propose to use this property for an approximate probabilistic optimization based
on exact capacity and approximate response distributions (ECARD). In Approximate Probabilistic Optimization Using ECARD, the
change in response distribution is approximated as the structure is re-designed while the capacity distribution is kept exact,
thus significantly reducing the number of expensive response simulations. ECARD may be viewed as an extension of SORA (Sequential
Optimization and Reliability Assessment), which proceeds with deterministic optimization iterations. In contrast, ECARD has
probabilistic optimization iterations, but in each iteration, the response distribution is approximated so as not to require
additional response calculations. The use of inexpensive probabilistic optimization allows easy incorporation of system reliability
constraints and optimal allocation of risk between failure modes. The method is demonstrated using a beam problem and a ten-bar
truss problem. The former allocates risk between two different failure modes, while the latter allocates risk between members.
It is shown that ECARD provides most of the improvement from risk re-allocation that can be obtained from full probabilistic
optimization. 相似文献