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排序方式: 共有1027条查询结果,搜索用时 15 毫秒
1.
2.
This paper presents a summary of the mechanical features and the medium term operating experience from three small horizontal axis wind energy conversion systems covering a range of 500 to 5000 Watt, intented for rural and isolated communities. These turbines have a new regulator which reduces gyroscopic loads, is easy to adjust and could be manufactured stronger and in smaller sizes than the conventional tail vanes. It is concluded that is feasible to build cheaps and reliable wind turbine generators with an acceptable efficiency employing common-use elements, but is needed a careful and optimized design. 相似文献
3.
M Pan J Suárez de Lezo A Medina M Romero E Hernández J Segura F Melian F Wangüemert M Landin F Benítez M Amat F Velasco A Torres 《Canadian Metallurgical Quarterly》1997,80(10):1336-1338
Two hundred twenty-eight patients with successful coronary stent implantation were randomized either to protamine administration and femoral sheath removal (group I, n = 117) or no heparin neutralization and delayed sheath removal (group II, n = 111). The hospital stay after treatment was shorter in patients receiving protamine; therefore, protamine use for neutralizing circulating heparin may be safely administered immediately after stent implantation. 相似文献
4.
G Martín Carballo R Codoceo Alquila G Fernández Cano F Hawkins Carranza C Grande Aragón A Velasco Hernando R Gracia Bouthelier 《Canadian Metallurgical Quarterly》1997,47(3):302-310
OBJECTIVE: The objective of this study was to determine fibronectin levels in umbilical cord blood of infants of diabetic mothers (IDM) and evaluate a possible correlation with perinatal pathology. PATIENTS AND METHODS: A prospective study of 58 IDM (33 males and 25 females) and 58 control newborns (NB) (33 males and 25 females) was carried out. RESULTS: There were no differences in fibronectin levels between the two groups nor between the sexes. Perinatal morbidity was higher in the IDM group, but there was no correlation between fibronectin levels and the presence of perinatal pathology. CONCLUSIONS: Fibronectin levels are not useful in the perinatal evaluation of infants of diabetic mothers. 相似文献
5.
I Santamaría G Velasco M Cazorla A Fueyo E Campo C López-Otín 《Canadian Metallurgical Quarterly》1998,58(8):1624-1630
We have identified and cloned a new member of the papain family of cysteine proteinases from a human brain cDNA library. The isolated cDNA codes for a polypeptide of 334 amino acids that exhibits all of the structural features characteristic of cysteine proteinases, including the active site cysteine residue essential for peptide hydrolysis. Pairwise comparisons of this amino acid sequence with the remaining human cysteine proteinases identified to date showed a high percentage of identity (78%) with cathepsin L; the percentage of identity with all other members of the family was much lower (<40%). On the basis of these structural characteristics, we have tentatively called this novel protein cathepsin L2. The cDNA encoding the mature cathepsin L2 was expressed in Escherichia coli, and after purification, the recombinant protein was able to degrade the synthetic peptide benzyloxycarbonyl-L-phenylalanyl-L-arginine-7-amido-4-methylcoumarin, which is commonly used as a substrate for cysteine proteinases. Cathepsin L2 proteolytic activity on this substrate was abolished by trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane, an inhibitor of cysteine proteinases, thus providing additional evidence that the isolated cDNA encodes a functional cysteine proteinase. Northern blot analysis of polyadenylated RNAs isolated from a variety of human tissues demonstrated that cathepsin L2 is predominantly expressed in the thymus and testis. This finding is in marked contrast with the wide tissue distribution of most cysteine proteinases characterized to date, including cathepsin L, and suggests that cathepsin L2 may play a specialized role in the thymus and testis. Expression analysis of cathepsin L2 in human tumors revealed a widespread expression in colorectal and breast carcinomas but not in normal colon or mammary gland or in peritumoral tissues. Cathepsin L2 was also expressed by colorectal and breast cancer cell lines as well as by some tumors of diverse origin, including ovarian and renal carcinomas. These results open the possibility that this novel enzyme may be involved in tumor processes, as already reported for other cysteine proteinases, including cathepsin L. 相似文献
6.
Mireia Casanovas Irene Reyes-Resina Alejandro Lillo Jaume Lillo Raul Lpez-Arnau Jorge Camarasa Elena Escubedo Gemma Navarro Rafael Franco 《International journal of molecular sciences》2021,22(5)
Methamphetamine is, worldwide, one of the most consumed drugs of abuse. One important side effect is neurodegeneration leading to a decrease in life expectancy. The aim of this paper was to check whether the drug affects one of the receptors involved in neurodegeneration/neuroprotection events, namely the adenosine A2A receptor (A2AR). First, we noticed that methamphetamine does not affect A2A functionality if the receptor is expressed in a heterologous system. However, A2AR becomes sensitive to the drug upon complexes formation with the cannabinoid CB1 receptor (CB1R) and the sigma 1 receptor (σ1R). Signaling via both adenosine A2AR and cannabinoid CB1R was affected by methamphetamine in cells co-expressing the two receptors. In striatal primary cultures, the A2AR–CB1R heteromer complex was detected and methamphetamine not only altered its expression but completely blocked the A2AR- and the CB1R-mediated activation of the mitogen activated protein kinase (MAPK) pathway. In conclusion, methamphetamine, with the participation of σ1R, alters the expression and function of two interacting receptors, A2AR, which is a therapeutic target for neuroprotection, and CB1R, which is the most abundant G protein-coupled receptor (GPCR) in the brain. 相似文献
7.
Peter Meszmer Karla Hiller Steffen Hartmann Alexey Shaporin Daniel May Raul David Rodriguez Jörg Arnold Gianina Schondelmaier Jan Mehner Dietrich R. T. Zahn Bernhard Wunderle 《Microsystem Technologies》2014,20(6):1041-1050
In this paper, a novel concept of a thermo-mechanical MEMS actuator using aluminum thin-film heaters on a thermal oxide for electrical insulation is presented. The actuator is part of an universal tensile testing platform for thermo-mechanical material characterization of one dimensional materials on a micro- and nano-scopic scale under different environmental conditions, as varying temperatures, pressure, moisture or even vacuum and is realised in BDRIE technology. It is shown, that the actuator concept fulfills the requirements for the use in a tensile loading stage along with heterogeneously integrated nanofunctional elements, following a specimen centered approach in line with bottom-up self-assembly processes. Simulation and experiment agree very well in the thermal and mechanical domain and allow subsequent optimisation of the actuator performance. 相似文献
8.
Cristina López‐Dehesa José A. González‐Marcos Juan R. González‐Velasco 《应用聚合物科学杂志》2007,103(5):2843-2848
Poly(1‐trimethylsilyl‐1‐propyne) (PTMSP) membranes have been used to separate ethanol–water mixtures by pervaporation. This polyacetylene is known to present high affinity toward ethanol, showing high selectivity and ethanol permeation flux. The performance of this polymer in the separation of alcohol–water solutions has been evaluated over long periods (572 h) at a high temperature (75°C) to examine the deterioration of the transport properties in the separation of 50 wt % ethanol–water solutions. Although PTMSP membranes present good characteristics for the separation of gases and liquid mixtures, their organic selectivity decrease with the operating time because of the relaxation processes of the polymeric chains, which affect the free volume of the polymer, the deterioration being more evident for concentrated solutions. The effects of the operation temperature on the characteristic parameters of pervaporation have also been studied to establish how this variable affects the performance of PTMSP membranes. The selectivity increases slightly with the operation temperature, but the effect of the temperature on the separation factor decreases as membranes are degraded with the operation time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2843–2848, 2007 相似文献
9.
Anibal Mario Nervi Raul Omar Peluffo Rodolfo R. Brenner Alicia Isabel Leikin 《Lipids》1980,15(4):263-268
The effect of ethanol on the fatty acid desaturation by rat liver has been studied using liquid diets of different composition.
Acute ethanol administration increased triacylglycerols of total liver lipids, but did not modify significantly the lipidic
composition of microsomes. The Δ6 and Δ5 desaturases were inhibited by ethanol whereas the Δ9 desaturase and fatty acid synthetase
were apparently modified only by diet composition. NADH-cytochrome (cyt.) c reductase was partially inhibited, whereas NADH-cyt.
b5 reductase remained practically unaltered and NADPH-cyt. c reductase activity was enhanced. Decreased electrons supplied by
the microsomal cyt. b5 electron transport chain would not be the reason for the inhibition of Δ6 and Δ5 desaturases by ethanol. 相似文献
10.
Male rats maintained at 24 C and then shifted to 5 C for 5 days increased food intake and decreased in growth rate and food
conversion. No modification was observed in Δ6 desaturase activity, while Δ9 desaturase activity decreased after this period
of time. These results were confirmed by liver microsomal and mitochondrial fatty acid composition. The phospholipid composition
of liver microsomes was unaltered, whereas in mitochondria, phosphatidylcholine and sphingomyelin decreased and phosphatidylethanolamine
increased due to the cold environment. The influence of food intake and weight changes on fatty acid metabolism was studied
using (i) rats maintained at 5 C with restricted food intake to match the food intake of those kept at 24 C with food ad libitum
and (ii) rats maintained at 24 C whose food intake was also restricted so that their growth rate would be the same as that
of rats maintained at 5 C with food ad libitum, respectively. These results indicate that the negative metabolic balance state
of these cold conditions is not an active factor modifier of Δ6 desaturase activity, whereas it decreases Δ9 desaturase activity,
reflecting the lipogenic characteristics of the latter enzyme. 相似文献