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41.
A short overview is given on wireless high speed data links for local-area-ad-hoc-networks in mobile applications and a multifunctional CDMA-Direct-Sequence Spread-Spectrum communicating platform is investigated which may be used for inter vehicle communication as well as for object detection and ranging in the environment of cars.  相似文献   
42.
Flow cytometric assays using peripheral blood were developed to study phagocytosis and respiratory burst, the two major functions of neutrophils and among the most important non-specific defense mechanisms, in beluga whales. The use of flow cytometry avoids the problems associated with the isolation and purification of different cell types, and allows the measurement of a large number of cells (10,000) in a very short period of time. The methods described will be used to compare these functions in blood samples from highly contaminated beluga whales from the St. Lawrence and from relatively clean arctic beluga whales.  相似文献   
43.
The intracellular mechanisms used by insulin and insulin-like growth factors to block programmed cell death are unknown. To identify receptor structures and signaling pathways essential for anti-apoptotic effects on cells, we have created a chimeric receptor (colony-stimulating factor-1 receptor/insulin receptor chimera (CSF1R/IR)) connecting the extracellular, ligand-binding domain of the colony-stimulating factor-1 (CSF-1) receptor to the transmembrane and cytoplasmic domains of the insulin receptor. Upon activation with CSF-1, the CSF1R/IR phosphorylates itself and intracellular substrates in a manner characteristic of normal insulin receptors. CSF-1 treatment protected cells expressing the CSF1R/IR from staurosporine-induced apoptosis. A chimeric receptor (CSF1R/IRDelta960) with a deletion of 12 amino acids from its juxtamembrane domain was constructed and expressed. CSF-1-treated cells expressing the CSF1R/IRDelta960 are unable to phosphorylate IRS-1 and Shc (Chaika, O. V., Chaika, N., Volle, D. J., Wilden, P. A. , Pirrucello, S. J., and Lewis, R. E. (1997) J. Biol. Chem. 272, 11968-11974). CSF-1 stimulated glucose uptake, mitogen-activated protein kinases, and IRS-1-associated phosphatidylinositol 3' kinase in cells expressing the CSF1R/IR but not in cells expressing the CSF1R/IRDelta960. Surprisingly, the CSF1R/IRDelta960 was as effective as the CSF1R/IR in mediating CSF-1 protection of cells from staurosporine-induced apoptosis. These observations indicate that the anti-apoptotic effects of the insulin receptor cytoplasmic domain can be mediated by signaling pathways distinct from those requiring IRS-1 and Shc.  相似文献   
44.
The importance of mitochondrial creatine kinase (mi-CK) in oxidative muscle was tested by studying the functional properties of in situ mitochondria in saponin-skinned muscle fibres from sarcomeric mi-CK-deficient (mutant) mice. Biochemical analyses showed that the lack of mi-CK in mutant muscle was associated with a decrease in specific activity of MM-CK in mutant ventricle, and increase in mutant soleus (oxidative) muscle. Lactate dehydrogenase activity and isoenzyme analysis showed an increased glycolytic metabolism in mutant soleus. No change was observed in ventricular muscle. In control animals, the apparent K(m) of mitochondrial respiration for ADP in ventricle and soleus (232 +/- 36 and 381 +/- 63 microM, respectively) was significantly reduced in the presence of creatine (52 +/- 8 and 45 +/- 12 microM, respectively). There was no change in the K(m) in oxidative fibres from mutant mice (258 +/- 27 and 399 +/- 66 microM, respectively) compared with control, though surprisingly, it was also significantly decreased in the presence of creatine (144 +/- 8 and 150 +/- 27 microM, respectively) despite the absence of mi-CK. It is proposed that in mutant (and perhaps normal) oxidative tissue, cytosolic MM-CK can relocate to the outer mitochondrial membrane, where it is coupled to oxidative phosphorylation by close proximity to porin, and the adenine nucleotide translocase. Such an effect can preserve the functioning of the CK shuttle and the energetic properties of mi-CK deficient tissue.  相似文献   
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Comments on D. T. Campbell's (see record 1976-12046-001) application of evolutionary theory to human social behavior and concludes that Campbell has impressively synthesized the thinking available in many fields concerning cultural evolution. However, in his analysis he has not carried certain psychological dimensions (i.e., variability, selection, retention) as far forward as information allows. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
48.
Boehm  B. 《Computer》1975,8(6):38-40
It has now been about four years since the first impressive experience using structured programming* techniques on a large production software project.1 Yet one still hears wildly varying claims about its effectiveness in general. Here are some recent samples.  相似文献   
49.
Four hundred seventy blood access procedures performed on 170 dialysis patients during the period 1962-1975 have been analyzed according to survival of access with respect to age, sex and cause of failure. Subcutaneous forms of blood access have a significantly longer life and are more free of complications than external shunts. Although the mode of access can now be tailored to the individual patient, the arterio-venous fistula remains the least expensive and simplest surgical procedure. It should therefore remain as the first choice of access for most patients.  相似文献   
50.
Examined 13 research studies dealing with differences between negroes and caucasians in the validity of employment and training selection procedures. It was found that 100 of the 160 validity coefficients computed were not significant for either group, indicating the need for validation prior to operational use. Significant differences in the coefficients between groups were found only in 7 instances. Statistical significance of single group validity occurred in 33 instances. The combination of ethnic groups yielded lower validity than for either group separately on only 3 out of 120 instances. It is concluded that there is very little evidence of differential validity. Single-group validity appears linked to the use of ratings (rather than more objective criterion measures), and small samples. (25 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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