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1.
M Kester RJ Nowinski H Holth?fer PA Marsden MJ Dunn 《Canadian Metallurgical Quarterly》1994,46(5):1404-1412
Platelet-activating factor synthesis in two transformed lines of glomerular endothelial cells was characterized and contrasted with platelet-activating factor production in macrovascular-derived endothelial cells as well as with glomerular cells of mesenchymal origin. Platelet-activating factor synthesis was assessed in intact cells and in cell-free preparations. Glomerular endothelial cells constitutively synthesize bio-active alkyl-PAF, and this basal activity can be chronically augmented by various inflammatory and thrombotic agents. In contrast, thrombin-mediated platelet-activating factor formation in bovine pulmonary aortic endothelial cells as well as in glomerular mesangial cells is acute and transient. The potential role of anti-inflammatory prostanoids to function as negative feedback modulators of thrombin- or endothelin-mediated platelet-activating factor synthesis was also investigated, as the synthesis of platelet-activating factor is often associated with the formation of these prostanoids. Indomethacin augmented receptor-mediated platelet-activating factor synthesis while prostanoids of the E and I series reduced agonist-stimulated PAF synthesis. In summary, the unique capacity of glomerular endothelial cells to respond to inflammatory stimuli with sustained platelet-activating factor synthesis is a clear indication of this cell's pivotal role in augmenting the inflammatory response in the limited environment of the glomerulus. 相似文献
2.
Kester Bruce E. Gilliland J. L. Fritts Stewart S. Bell Zeb G. Smith Hubert Berby Richard H. 《Industry Applications, IEEE Transactions on》1972,(1):8-18
MAN is but a part of the universe; his capabilities make him a significant link, in the cycle of life. To ensure this life, man must live in harmony with his environment. Recently, a disharmony has been discovered which could have grave effects upon the existence of man. It appears that man in his great thrust forward is destroying his own environment. The gravity of this threat to man's own existence carries some intrinsic problems of its own: man must allow his reason rather than his emotion to take command. 相似文献
3.
Fully-hydrogenated soybean and rapeseed oil was blended 2:1, layered on a filter paper support, adjusted to the desired polymorphic
form and tested for resistance to transmission to oxygen and water vapor. Resistance to oxygen transport decreased upon conversion
from α to the β′ form and then increased substantially upon conversion to the β polymorph. This was attributed to the greater
solid-state density of the β form, which likely affects resistance to gas flux by lowering the oxygen diffusion constant through
the film. Resistance to water vapor transmission also decreased following the α to β′ transition and then increased somewhat
upon conversion to the β form. However, resistance of the β form did not exceed that of the α form at any of the temperatures
tested. Moisture sorption characteristics of the various polymorphic forms apparently caused relative resistance values for
water vapor flux to differ, somewhat from those for oxygen flux. 相似文献
4.
Ronald J. Jandacek Jeffrey J. Kester A. J. Papa Thomas J. Wehmeier Peter Y. T. Lin 《Lipids》1999,34(8):771-783
Olestra is a mixture of compounds comprising sucrose esterified with 6–8 long-chain fatty acids. It is not hydrolyzed by pancreatic lipase and as a result is not absorbed from the small intestine. Olestra in general has physical properties similar to those of a triacylglycerol with the same fatty acid composition. Foods made with olestra are virtually identical in taste and texture to those made with typical triacylglycerols. Olestra consumption does not generate hydrolytic products in the small intestine and, therefore, does not generate some of the signals that alter motility in the gastrointestinal tract. A reduction in gastroesophageal reflux with olestra, in contrast to triacylglycerols, is consistent with a lack of effect on stomach emptying. Unlike triacylglycerols that are absorbed in the proximal small intestine, olestra is distributed throughout the small intestine during transit and passes into the colon. In the colon, olestra's effects depend on its physical properties. Liquid nondigestible lipids result in separation of oil from the fecal matrix. Olestra formulations made with specific fatty acid compositions, particularly those containing a solid sucrose polyester component including behenic acid, possess appropriate rheology to hinder separation of oil from the rest of the fecal matrix, thereby reducing gastrointestinal symptoms. 相似文献
5.
Various lipids, mounted on a polar filter paper matrix, were evaluated as barriers to O2 transmission Among those lipids tested, stearyl alcohol was most resistant to oxygen transmission, the most likely reason
being its ability to crystallize as compactly overlapping platelets with their planes normal to the direction of O2 diffusion. Tristearin, beeswax, and acetylated monoglycerides were, respectively, 39, 43 and 61% less resistant to O2 transmission than the fatty alcohol. Activation energies of O2 transport were. 7.0, 7.5, 15.0 and 27.5 kcal/mole, respectively, for stearyl alcohol, tristearin, beeswax, and acetylated
monoglycerides. Stearic acid was substantially less resistant to O2 flux than the above four lipids. In addition, the fatty acid was unique among the, lipids tested in its temperature dependence,
i.e., resistance to O2 transmission increased with elevation of temperature yielding a negative activation energy of −17.2 kcal/mole. This was attributed
to the presence of small interplatelet channels in the stearic acid film, which presumably act as the principal route for
gas transport. Hexatriacontane displayed poor O2 barrier properties compared to the other lipids, a consequence of relatively large pores in the alkane film. 相似文献
6.
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8.
An electron gun, which can be switched from immersed flow to Brillouin flow during operation, may have advantages for charge breeders as well as for electron beam ion sources and traps (EBISTs). For EBISTs this allows to change the current density according to the repetition frequency and charge state, for charge breeders and EBISTs a lower current density in immersed flow provides higher acceptance for injected ions, while the higher current density in Brillouin flow results in shorter breeding times and a lower emittance for the extracted beam. Therefore, we have designed such a gun for an EBIS with 5 T central magnetic field and without the use of iron and moving the gun. The gun was placed in the axial fringing field of the 5 T solenoid in such a position that a gate valve can be placed between the gun and the cryostat to allow for simple maintenance. The field at the cathode surface turned out to be only 0.05 T, which is not enough to focus 50 A∕cm(2) at a few kV. However, if a small normal conducting solenoid is placed over the vacuum tube in position of the gun, a field of 0.1 T may be obtained. With this the use of LaB(6) as cathode material results in a magnetic compression of 44 and therewith in a focused current density in the trap region of more than 2000 A∕cm(2). By reversing the current in the gun solenoid the cathode field can easily compensated to zero. By proper design of the electrodes and the compression region, the gun will be able to deliver a beam in Brillouin flow. While this is interesting by itself--remember the "super-compression" reported on CRYEBIS-I--any magnetic field between zero and the value for immersed flow will result in an electron beam with a wide range of adjustable high current densities. The design tools used have been INTMAG(C) for the calculation of magnetic fields, EGN2(C) for the simulation of the gun and ANALYSE(C) for detailed analysis of the results (for more information see www.egun-igun.com). 相似文献
9.
Kester D. Clarke Robert J. ComstockJr. Martin C. Mataya Chester J. van Tyne David K. Matlock 《Metallurgical and Materials Transactions A》2008,39(4):752-762
The effect of strain rate on the yield stress of ferritic stainless steel sheet was experimentally determined and a previously
developed model was applied to the data. Five ferritic stainless steel alloys, including one in two thicknesses, were mechanically
tested at room temperature in uniaxial tension at strain rates ranging from 0.001 to 300 s−1, and low-strain-rate tests were selectively performed at nonambient temperatures. The hypothesis that ferritic stainless
steels react similarly to strain rate as mild steels was investigated by the application of a widely accepted strengthening
model, based on body-centered-cubic (bcc) crystal lattice deformation mechanisms, to the experimental data.[1] Yield stresses were compared to model predictions and good agreement was found. The results allow for the prediction of
yield stresses for these materials over strain rate ranges of 0.001 to 300 s−1, and as a function of test temperature. Model parameters for the ferritic stainless steels were reasonable relative to those
previously reported for pure bcc ferritic iron.[1] A correlation between the effect of alloying additions on solid solution strengthening and the athermal component of shear
stress is also suggested. The results allow prediction of yield stress of ferritic stainless steels over a wide range of strain
rates and temperatures.
This article is based on a presentation made in the symposium entitled “Dynamic Behavior of Materials,” which occurred during
the TMS Annual Meeting and Exhibition, February 25–March 1, 2007 in Orlando, Florida, under the auspices of The Minerals,
Metals and Materials Society, TMS Structural Materials Division, and TMS/ASM Mechanical Behavior of Materials Committee.
相似文献
Kester D. Clarke (Graduate Research Assistant)Email: |
10.
Although current evidence suggests that respiratory care protocols can enhance allocation of respiratory care services while conserving costs, a randomized trial is needed to address shortcomings of available studies. We therefore conducted a randomized controlled trial comparing respiratory care for adult non-ICU inpatients directed by a Respiratory Therapy Consult Service (RTCS) versus respiratory care by managing physicians. Eligible subjects were adult non-ICU inpatients whose physicians had prescribed specific respiratory care services. Consecutive eligible patients were approached for consent, after which a blocked randomization strategy was used to assign patients to (1) Physician-directed respiratory care, in which the prescribed physician respiratory care orders were maintained (n = 74), or (2) RTCS-directed respiratory care, in which the physician's respiratory care orders were preempted by a respiratory care plan generated by the RTCS (n = 71). Specifically, these patients were evaluated by an RTCS therapist evaluator whose respiratory care plan was based on sign/symptom-based algorithms drafted to comply with the American Association for Respiratory Care (AARC) Clinical Practice Guidelines. Appropriateness of respiratory care orders was assessed as agreement between the prescribed respiratory care plan and an algorithm-based "standard care plan" generated by an expert therapist who was blind to the patient's actual orders. The compared groups were similar at baseline regarding demographic features, admission diagnostic category, smoking status, and Triage Score (mean, 3.8 +/- 0.9 SD [RTCS] versus 3.7 +/- 1.0). Similarly, no differences were observed between RTCS-directed and physician-directed respiratory care regarding hospital mortality rate (5.7 versus 5.6%), hospital length of stay (7.9 +/- 9.0 versus 7.7 +/- 7.3 d), total number of respiratory care treatments delivered (30.3 +/- 30 versus 31.6 +/- 30.5), or days requiring respiratory care (4.2 +/- 5.2 versus 4.1 +/- 3.6). Notably, using both a stringent (S) and a liberal (L) criterion for agreement, RTCS-directed respiratory care demonstrated better agreement with the "standard care plan" (82 +/- 17% [S] and 86 +/- 16% [L]) than did physician-directed respiratory care (64 +/- 21% [S] and 72 +/- 23% [L]) (p < 0.001). Finally, the true cost of respiratory care treatments was slightly lower with RTCS-directed respiratory care (mean, $235.70 versus $255.70/pt, p = 0.61). We conclude that (1) compared with physician-directed respiratory care, the RTCS prescribed a similar number and duration of respiratory care services at a slight savings (that did not achieve statistical significance) and without any increased adverse events; and (2) compared with physician-directed respiratory care, RTCS-directed respiratory care showed greater agreement with Clinical Practice Guideline-based algorithms. 相似文献