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1.
M. Penchal Reddy R.A. Shakoor Gururaj Parande Vyasaraj Manakari F. Ubai A.M.A. Mohame Manoj Gupta 《自然科学进展(英文版)》2017,27(5):606-614
In the present study, nano-sized SiC (0, 0.3, 0.5, 1.0 and 1.5 vol%) reinforced aluminum (Al) metal matrix
composites were fabricated by microwave sintering and hot extrusion techniques. The structural (XRD, SEM),
mechanical (nanoindentation, compression, tensile) and thermal properties (co-efficient of thermal expansion-
CTE) of the developed Al-SiC nanocomposites were studied. The SEM/EDS mapping images show a
homogeneous distribution of SiC nanoparticles into the Al matrix. A significant increase in the strength
(compressive and tensile) of the Al-SiC nanocomposites with the addition of SiC content is observed. However,
it is noticed that the ductility of Al-SiC nanocomposites decreases with increasing volume fraction of SiC. The
thermal analysis indicates that CTE of Al-SiC nanocomposites decreases with the progressive addition of hard
SiC nanoparticles. Overall, hot extruded Al 1.5 vol% SiC nanocomposites exhibited the best mechanical and
thermal performance as compared to the other developed Al-SiC nanocomposites. 相似文献
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Kozyrev SV Abelson AK Wojcik J Zaghlool A Linga Reddy MV Sanchez E Gunnarsson I Svenungsson E Sturfelt G Jönsen A Truedsson L Pons-Estel BA Witte T D'Alfonso S Barizzone N Barrizzone N Danieli MG Gutierrez C Suarez A Junker P Laustrup H González-Escribano MF Martin J Abderrahim H Alarcón-Riquelme ME 《Nature genetics》2008,40(2):211-216
5.
Zusammenfassung Es wird nachgewiesen, dass die Aktivität von Succinat Dehydrogenase und von Pyruvat Dehydrogenase in Extrakten normaler und denervierter Muskulatur durch Ca++ im pH-Bereich von 5,8 bis 7,8 in verschiedenem Ausmass erhöht bzw. erniedrigt wird. 相似文献
6.
Cystic fibrosis is caused by mutations in cystic fibrosis transmembrane conductance regulator (CFTR), an anion channel. Phosphorylation and ATP hydrolysis are generally believed to be indispensable for activating CFTR. Here we report phosphorylation- and ATP-independent activation of CFTR by cytoplasmic glutamate that exclusively elicits Cl-, but not HCO3-, conductance in the human sweat duct. We also report that the anion selectivity of glutamate-activated CFTR is not intrinsically fixed, but can undergo a dynamic shift to conduct HCO3- by a process involving ATP hydrolysis. Duct cells from patients with DeltaF508 mutant CFTR showed no glutamate/ATP activated Cl- or HCO3- conductance. In contrast, duct cells from heterozygous patients with R117H/DeltaF508 mutant CFTR also lost most of the Cl- conductance, yet retained significant HCO3- conductance. Hence, not only does glutamate control neuronal ion channels, as is well known, but it can also regulate anion conductance and selectivity of CFTR in native epithelial cells. The loss of this uniquely regulated HCO3- conductance is most probably responsible for the more severe forms of cystic fibrosis pathology. 相似文献
7.
P. Sreenivasula Reddy A. Bhagyalakshmi R. Ramamurthi 《Cellular and molecular life sciences : CMLS》1983,39(12):1354-1355
Summary A single injection of the hyperglycemic principle obtained from scorpion cephalothoracic ganglionic mass causes an elevation of glycemia in the scorpionH. fulvipes in which little glucose is involved (10.8%). With the crustacean hyperglycemic principle, the elevation of glycemia is initially almost exclusively contributed by glucose (glucose is 92% of total carbohydrate at 2 h post injection); 6 h after treatment, non-glucose carbohydrates appear to participate in the elevation of glycemia.Acknowledgments. We wish to express our gratitude to CSIR, New Delhi for providing financial support to P.S.R., Reprint requests should be addressed to Prof. R. Ramamurthi. 相似文献
8.
Summary Injection of eyestalk extracts of freshwater crab and marine prawn caused elevation of haemolymph sugar level, and decrease in free sugar and glycogen levels, in the hepatopancreas of the scorpion. 相似文献
9.
The initiation and progress of regeneration following the removal of the left 4th walking leg were altered in the crab (Oziotelphusa senex senex) by exposure to sumithion. Depending on the concentration used, sumithion caused a complete inhibition of regeneration, a delay of initiation of limb bud development or a reduction of limb bud growth rate. Crustacean limb regeneration can also be used as a sensitive bioassay for studying the effects of environmental pollutants. 相似文献
10.
Atmospheric aerosols cause scattering and absorption of incoming solar radiation. Additional anthropogenic aerosols released into the atmosphere thus exert a direct radiative forcing on the climate system. The degree of present-day aerosol forcing is estimated from global models that incorporate a representation of the aerosol cycles. Although the models are compared and validated against observations, these estimates remain uncertain. Previous satellite measurements of the direct effect of aerosols contained limited information about aerosol type, and were confined to oceans only. Here we use state-of-the-art satellite-based measurements of aerosols and surface wind speed to estimate the clear-sky direct radiative forcing for 2002, incorporating measurements over land and ocean. We use a Monte Carlo approach to account for uncertainties in aerosol measurements and in the algorithm used. Probability density functions obtained for the direct radiative forcing at the top of the atmosphere give a clear-sky, global, annual average of -1.9 W m(-2) with standard deviation, +/- 0.3 W m(-2). These results suggest that present-day direct radiative forcing is stronger than present model estimates, implying future atmospheric warming greater than is presently predicted, as aerosol emissions continue to decline. 相似文献