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排序方式: 共有164条查询结果,搜索用时 15 毫秒
81.
82.
Hiza Ronald J. 《润滑油》2011,26(3)
In this paper,the effect of using hindered phenol,zinc dialkyl dithiocarbamate(ZDDC),tolutriazole derivative and combinations thereof to inhibit a blend of commodity Canola Oil and high oleic content soybean oil(1:1) was investigated.Specifically,oils were oxidized by bubbling oxygen through 300 mL samples heated at 95 ℃.Antioxidant depletion rates were indirectly monitored by measuring oxidation induction times(OIT) as determined by Pressure Differential Scanning Calorimetry(PDSC).Preliminary data indicate... 相似文献
83.
More than 1,800 junior high school students were surveyed regarding sexual activity. It was found that females were less likely to have "ever had sex" but among nonvirgins there was little gender difference in frequency or recency. Items measuring sexual values indicated greater commitment to abstinence and less permissive sexual attitudes among females. Females also saw sexual activity as more detrimental to future goal attainment. They viewed parents as less approving, but were more likely to discuss sex and dating practices with them. They reported parents as having more rules and were more likely to believe that they were unfair, and that they had gone against the parents' rules. Females perceived less peer pressure for sex and more support for waiting. However, more males anticipated partner pressure for sex and believed they might "have sex" before marriage. Males and females reported no difference in the importance of parenthood, but more females saw teen parenthood as a problem. No gender differences were found for smoking or drinking. Significantly more males had experienced petting behavior. Females were more likely to believe that sexual urges can be controlled. It was concluded that understanding these differences can help in the design of sex education and social programs to address problems associated with adolescent sexuality. 相似文献
84.
85.
F Ricolfi C Le Guerinel J Blustajn C Combes P Brugieres E Melon A Gaston 《Canadian Metallurgical Quarterly》1998,19(9):1653-1658
BACKGROUND AND PURPOSE: We describe four cases of aneurysmal rupture during embolization with Guglielmi electrodetachable coils (GDCs) in an attempt to identify those aneurysms whose rupture during embolization represents a life-threatening risk; our emphasis is on emergency management, in particular, ventriculostomy. METHODS: Medical records were reviewed retrospectively for 91 aneurysms treated with GDCs 0 to 21 days after subarachnoid hemorrhage. Rupture was ascertained by the presence of extravascular effusion of contrast medium. RESULTS: Of the perforated aneurysms, two involved the anterior communicating artery, one the posterior inferior communicating artery, and one the basilar artery. Only two patients, whose aneurysms were located in the posterior fossa, had major complications (arterial hyperpressure, mydriasis, angiographically documented circulatory arrest or slowing). One of these patients died and the other improved after emergency ventriculostomy. CONCLUSION: Aneurysmal perforation during embolization may be accompanied by severe intracranial hypertension, which causes either a decrease or arrest of cerebral perfusion, the duration of which determines clinical outcome. Emergency ventriculostomy (which should be performed in the angiographic suite) is an effective means to reduce intracranial pressure. Recognition of aneurysms associated with a high risk of mortality by rupture in the course of embolization (recently ruptured small aneurysms, posterior fossa aneurysms, associated ventricular dilatation, massive cisternal hemorrhage) and use of proper logistics should ensure the effective management of this devastating complication. 相似文献
86.
GH Vondenhoff B Gadakh K Severinov A Van Aerschot 《Chembiochem : a European journal of chemical biology》2012,13(13):1959-1969
In 1998, Cubist Pharmaceuticals patented a series of aminoacyl tRNA synthetase (aaRS) inhibitors based on aminoacyl sulfamoyladenosines (aaSAs), in which the adenine was substituted by aryl-tetrazole moieties linked to the ribose fragment by a two-carbon spacer. Although potent and specific inhibitors of bacterial IleRS, these compounds did not prove successful in vivo due to low cell permeability and strong binding to serum albumin. In this work, we attempted to improve these compounds by combining them with microcin C (McC) or albomycin (i.e., siderophore-drug conjugate (SDC)) transport modules. We found that aryl-tetrazole variants of McC and albomycin still lacked antibacterial activity. However, these compounds were readily processed by E. coli aminopeptidases with the release of toxic aaRS inhibitors. Hence, the lack of activity in whole-cell assays was due to an inability of the new compounds to be taken up by the cells, thus indicating that the nucleotide moieties of McC and albomycin strongly contribute to facilitated transport of these compounds inside the cell. 相似文献
87.
Lately, researchers around the world have developed effective chemical and physical treatments on plant fibers to improve their compatibility with polymeric matrices. In addition, the need of high performance fabrics produced from plant fibers has been addressed by many manufacturers of textile reinforcements. These facts have increased the use of natural fibers in the composite industry. Liquid composite molding (LCM) techniques are suitable for mass production of high‐quality composite parts. Basically, the reinforcement is compressed inside a mold and a thermosetting resin is injected to impregnate the fibers and fill the empty spaces in the mold. After the resin cures, the composite part is demolded. However, the processing of plant fiber–reinforced composites by the traditional techniques is not trivial, because the structure of plant fibers is more complex than that of synthetic fibers and due to their chemical composition rich in cellulose and hemicellulose, they are highly hydrophilic. This work presents a review on the main issues that arise during the processing of plant fiber reinforced composites by traditional liquid composite molding techniques. POLYM. COMPOS., 37:718–733, 2016. © 2014 Society of Plastics Engineers 相似文献
88.
Gaston Castillo Ralf Kleene Melitta Schachner Gabriele Loers Andrew E. Torda 《International journal of molecular sciences》2021,22(15)
The human natural killer (HNK-1) carbohydrate plays important roles during nervous system development, regeneration after trauma and synaptic plasticity. Four proteins have been identified as receptors for HNK-1: the laminin adhesion molecule, high-mobility group box 1 and 2 (also called amphoterin) and cadherin 2 (also called N-cadherin). Because of HNK-1′s importance, we asked whether additional receptors for HNK-1 exist and whether the four identified proteins share any similarity in their primary structures. A set of 40,000 sequences homologous to the known HNK-1 receptors was selected and used for large-scale sequence alignments and motif searches. Although there are conserved regions and highly conserved sites within each of these protein families, there was no sequence similarity or conserved sequence motifs found to be shared by all families. Since HNK-1 receptors have not been compared regarding binding constants and since it is not known whether the sulfated or non-sulfated part of HKN-1 represents the structurally crucial ligand, the receptors are more heterogeneous in primary structure than anticipated, possibly involving different receptor or ligand regions. We thus conclude that the primary protein structure may not be the sole determinant for a bona fide HNK-1 receptor, rendering receptor structure more complex than originally assumed. 相似文献
89.
Mapping research topics using word-reference co-occurrences: A method and an exploratory case study 总被引:2,自引:0,他引:2
Summary Mapping of science and technology can be done at different levels of aggregation, using a variety of methods. In this paper,
we propose a method in which title words are used as indicators for the content of a research topic, and cited references
are used as the context in which words get their meaning. Research topics are represented by sets of papers that are similar
in terms of these word-reference combinations. In this way we use words without neglecting differences and changes in their
meanings. The method has several advantages, such as high coverage of publications. As an illustration we apply the method
to produce knowledge maps of information science. 相似文献
90.
A novel parallel architecture which combines the processing power of VLSI technology with the communication advantages of optical interconnects is presented for parameter estimation based on the square root covariance Kalman filter.<> 相似文献