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1.
2.
Electrolytic hydrogen saturation of polycrystalline aluminum leads to a significant (up to about 30%) decrease in the shear moduli G of samples. This change in G is accompanied neither by the loss of plasticity (no hydrogen-induced brittleness) nor by a change in the electric resistance (in contrast to that observed during the hydrogenation of typical hydride-forming metals and alloys, including those in the amorphous state). 相似文献
3.
R Drozdenko SC Pennisi W Minkin H Spivak S Weinstein C Weinstein 《Canadian Metallurgical Quarterly》1996,9(5):334-342
A model has been developed to determine the effectiveness of topical antipruritics. It utilizes controlled, experimentally induced itch and has demonstrated the effectiveness of the direct action on cutaneous receptor sites of a topical anesthetic, benzocaine, in a topical antipruritic formulation, and has been used to differentiate between two effective topical antipruritics. Three studies are presented: The first study examined the reliability of the experimentally induced itch. Several indices of reliability were computed from the data of this first study. Cronbach's alpha was 0.92. Winer's theta also was 0.92. Simple test-retest reliability, computed at intervals of 29 min, 1 day, and 6-7 days, resulted in Pearson correlations of 0.84, 0.73, and 0.60, respectively. In the second study, the model differentiated statistically between the itch relief resulting from the topical application of a formulation with 6% benzocaine and the same formulation without benzocaine. The third study examined 2 known topical antipruritics: one containing 6% benzocaine and the other 1% hydrocortisone. Both topical antipruritics were found to relieve itch; however, the benzocaine antipruritic produced statistically significantly greater itch relief in more subjects than the hydrocortisone antipruritic at both 1 and 30 min after application. These results demonstrate that OTC antipruritics can be differentiated for effectiveness. 相似文献
4.
Conclusions At temperatures of up to 1400°C hot pressing under isothermal conditions enables higher (by 5%) densities to be obtained in compacts from-Al2O3 powders than in compacts from-Al2O3 powders. With rise in temperature the difference between the densification rates of- and -Al2O3 powders diminshes. The difference in density between- and-Al2O3 compacts is preserved up to a temperature of 1600°C in hot pressing at a constant heating rate of 5 deg C/min. In the temperature range 1300–18QO°C the energy of activation for hot pressing Al2O3 varies from 50 to 75 kcal/g· form. Estimated values of viscosity and effective diffusion coefficient are in accord with values determined in creep and sintering experiments.Translated from Poroshkovaya Metallurgiya, No. 9(165), pp. 76–80, September, 1976. 相似文献
5.
This paper considers the issue of solving the inverse problem for a Markov model using an actuarial scheme as a corresponding example. 相似文献
6.
James F. Hoebel Gordon H. Damant Steven M. Spivak Geoffrey N. Berlin 《Fire Technology》2010,46(3):629-649
Between 1997 and 2006, more than 4,300 serious burn injuries per year in the United States were associated with clothing.
Ages 5–14 had the highest average annual burn injury rate, and ages 25–64 had the lowest rate. There were 120 deaths per year
in the United States associated with clothing burns between 1999 and 2004. The death rate for those over 65 was six times
the national average. The General Wearing Apparel Standard has regulated the flammability of clothing worn in the United States
since 1953. Nearly all of the clothing-related injuries and deaths have occurred in fires involving apparel that complied
with this Standard. Despite the size of this problem, there is no organized national activity under way to begin to address
these casualties. Experience with the Children’s Sleepwear Flammability Standards, issued in the 1970s, suggests that safer
garments can be manufactured that would prevent many clothing burn injuries and deaths. A more stringent up-to-date flammability
standard, production of safer garments, use of warning labels, and educated consumers are needed. 相似文献
7.
STUDY DESIGN: Iliac crest corticocancellous allografts for anterior interbody fusion were harvested from six cadavers. The grafts were cut sequentially from left and right crests and randomly assigned to tricortical or bicortical preparations. Their compression strengths then were determined and compared by matched pair analysis. OBJECTIVES: To quantify the failure strength of the grafts from different iliac locations and determine the optimal type of preparation of the grafts for anterior interbody fusion. SUMMARY OF BACKGROUND DATA: Iliac crest corticocancellous autografts and allografts commonly are used for interbody cervical fusions. However, graft strengths for specific sites have not been determined fully. METHODS: Six paired, fresh frozen, iliac crests were sectioned using a customized miter box into multiple 1-cm-thick grafts 1.5 cm in depth to simulate cervical interbody grafts. The left and right sides of each pair were randomly assigned to tricortical and bicortical preparations. The samples were tested by applying a compressive load to failure using a specialized fixture to simulate vertebral body loading. RESULTS: The grafts closer to the anterosuperior iliac spine had significantly higher failure loads and failure strengths than those closer to the posterosuperior iliac spine. The strengths of the bicortical grafts were 72 +/- 14% of the strengths of the tricortical grafts (P < 0.001). CONCLUSIONS: Anterior iliac crest grafts were stronger in compression, even after removal of one cortical surface, than posterior iliac crest grafts. 相似文献
8.
Mechanical characteristics of rock massifs and constituent rocks in the zones of influence of underground nuclear explosions are experimentally determined. Zones with a different postexplosion structure of the rock massif and different properties of rocks are identified. 相似文献
9.
Glutamate receptors play a major role in neural cell plasticity, growth, and maturation. The degree to which ionotropic glutamate
receptors (iGluR) conduct current is dependent on binding of extracellular ligands, of which glutamate is the native agonist.
Although the glutamate binding site of the GluR2 class of amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) iGluR
has been structurally characterized, the allosteric sites attributed to neurosteroid binding have yet to be localized. Here,
using intrinsic tryptophan fluorescence spectroscopy, we show that the extracellular glutamate binding core of the GluR2 class
of AMPA receptors also binds to two neurosteroids, pregnenolone sulfate (PS) and 3α-hydroxy-5β-pregnan-20-one sulfate, both
of which negatively modulate its activity. Interest in these sulfated neurosteroids stems from their differential modulation
of other members of the iGluR family and their potential use as endogeneous agents for stroke therapy. In particular, whereas
PS inhibits AMPA and other non-N-methyl-d-aspartate (NMDA) family members, it activates the NMDA receptor. In addition to providing evidence for binding of these neurosteroids
to the glutamate binding core of the GluR2 class of AMPA receptors, our data suggests that both neurosteroids bind in a similar
manner, consistent with their modulation of activity of this class of iGluR. Interestingly, the conformational change induced
upon binding of these neurosteroids is distinct from that induced upon glutamate binding. 相似文献
10.