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41.
The authors tested the shifting standards model (M. Biernat, M. Manis, & T. E. Nelson, 1991) as it applies to sex- and race-based stereotyping of self and others in the military. U. S. Army officers attending a leadership training course made judgments of their own and their groupmates' leadership competence at 3 time points over a 9-week period. We examined the effects of officer sex and race on both subjective (rating) and objective/common-rule (ranking/Q-sort) evaluations. Stereotyping generally increased with time, and in accordance with the shifting standards model, pro-male judgment bias was more evident in rankings than in ratings, particularly for White targets. Self-judgments were also affected by sex-based shifting standards, particularly in workgroups containing a single ("solo") woman. Differential standard use on the basis of race was less apparent, a finding attributed to the Army's explicit invocation against the use of differential race-based standards.  相似文献   
42.
Structural features of three regions of the capsaicin molecule necessary for agonist properties were delineated by a previously reported modular approach. These in vitro agonist effects were shown to correlate with analgesic potency in rodent models. Combination of optimal structural features from each of these regions of the capsaicin molecule have led to highly potent agonists (eg., 1b). Evaluation in vivo established that 1b had analgesic properties but poor oral activity, short duration of action, and excitatory side effects which precluded further development of this compound. Preliminary metabolism studies had shown that the phenol moiety of 1b was rapidly glucuronidated in vivo, providing a possible explanation for the poor pharmacokinetic profile. Subsequent specific modification of the phenol group led to compounds 2a-j, which retained in vitro potency. The in vivo profiles of two representatives of this series, 2a,h, were much improved over the "parent" phenol series, and they are candidates for development as analgesic agents.  相似文献   
43.
Roald Amundsen is the most famous of the Norwegian polar explorers. His ancestors came from a group of islands south-east of the Oslofjord. From being fishermen and sailors, they progressed to becoming captains and shipowners in the course of two generations. Amundsen's father, Jens, stayed at sea until his ship went down with all the crew. Roald was 14 years of age at the time, the youngest of four competing brothers. Jens had left the close-knit local family community before that, and bought a flat in the capital, Oslo, so that his sons could get a better education. Roald's mother wanted him to study medicine. He did as she wished for a time, but was not at all interested. When his mother died, he abruptly left the university and went to sea, which had been the tradition in his family for decades. As a young boy he was an admirer of Sir John Franklin and his explorers of the Northwest Passage. Fridtjof Nansen became his ideal. The biographies about Roald Amundsen are very diverging--some hold him a hero, others reflect a strongly critical attitude. Here, the author tries to define his personality and places him firmly within the narcissistic domain. His tendency to seek the company of married women, but to take immediate flight when they really became interested reflects an Oedipus complex from before puberty. The tragic death of his father, the sea captain, may have been a supposition; puberty can be seen as a period of coping with ambivalence towards an earlier idealized father. His genius combined ambitious goals with a sharp eye for details as regards the equipment used in his expeditions. In his travels in the Arctic and the Antartic he was driven forward by the energy of the nation. His heroic death, trying to save his earlier "enemy", Nobile, was probably caused by an urge for self-destruction.  相似文献   
44.
The Arabidopsis CHL1 (AtNRT1) gene confers sensitivity to the herbicide chlorate and encodes a nitrate-regulated nitrate transporter. However, how CHL1 participates in nitrate uptake in plants is not yet clear. In this study, we examined the in vivo function of CHL1 with in vivo uptake measurements and in situ hybridization experiments. Under most conditions tested, the amount of nitrate uptake by a chl1 deletion mutant was found to be significantly less than that of the wild type. This uptake deficiency was reversed when a CHL1 cDNA clone driven by the cauliflower mosaic virus 35S promoter was expressed in transgenic chl1 plants. Furthermore, tissue-specific expression patterns showed that near the root tip, CHL1 mRNA is found primarily in the epidermis, but further from the root tip, the mRNA is found in the cortex or endodermis. These results are consistent with the involvement of CHL1 in nitrate uptake at different stages of root cell development. A functional analysis in Xenopus oocytes indicated that CHL1 is a low-affinity nitrate transporter with a K(m) value of approximately 8.5 mM for nitrate. This finding is consistent with the chlorate resistance phenotype of chl1 mutants. However, these results do not fit the current model of a single, constitutive component for the low-affinity uptake system. To reconcile this discrepancy and the complex uptake behavior observed, we propose a "two-gene" model for the low-affinity nitrate uptake system of Arabidopsis.  相似文献   
45.
The effects of 27 mM K+ and of 6.7 mM theophylline on the release of growth hormone (GH) by rat hemipituitaries in vitro were investigated using bioassay (rat tibia test) and radioimmunoassay (RIA). Both agents markedly increased the release of immunoreactive GH. High K+ also promoted the release of bioactive GH but to a much lesser degree than RIA-GH. Theophylline did not consistently affect the release of bioassay-detectable GH. The results suggest that these agents promote massive release of a form of immunoreactive GH (possibly "immature") that has little or no activity in the bioassay. Theophylline is relatively more effective in this regard than is elevated K+.  相似文献   
46.
Dynamic alterations in flavin adenine dinucleotide (FAD) fluorescence permit insight into energy metabolism‐dependent changes of intramitochondrial redox potential. Monitoring FAD fluorescence in living tissue is impeded by photobleaching, restricting the length of microfluorimetric recordings. In addition, photodecomposition of these essential electron carriers negatively interferes with energy metabolism and viability of the biological specimen. Taking advantage of pulsed LED illumination, here we determined the optimal excitation settings giving the largest fluorescence yield with the lowest photobleaching and interference with metabolism in hippocampal brain slices. The effects of FAD bleaching on energy metabolism and viability were studied by monitoring tissue pO2, field potentials and changes in extracellular potassium concentration ([K+]o). Photobleaching with continuous illumination consisted of an initial exponential decrease followed by a nearly linear decay. The exponential decay was significantly decelerated with pulsed illumination. Pulse length of 5 ms was sufficient to reach a fluorescence output comparable to continuous illumination, whereas further increasing duration increased photobleaching. Similarly, photobleaching increased with shortening of the interpulse interval. Photobleaching was partially reversible indicating the existence of a transient nonfluorescent flavin derivative. Pulsed illumination decreased FAD photodecomposition, improved slice viability and reproducibility of stimulus‐induced FAD, field potential, [K+]o and pO2 changes as compared to continuous illumination.  相似文献   
47.
As different hepatitis C virus (HCV) genotypes respond differently to initiated therapy, correct HCV genotyping is essential. A potential risk for misclassification of the intergenotypic HCV circulating recombinant form (CRF) 2k/1b strains exists, depending on the genotyping method used. The aim was to investigate the differences in HCV genotyping methods with regard to CRF 2k/1b and to gain insight in the prevalence of the CRF 2k/1b. Genotyping results by Versant HCV Genotype Assay were compared with nonstructural protein 5B (NS5B) sequencing. In total, from November 2001 until March 2015, 3296 serum samples were analyzed by Versant HCV Genotype Assay. As misclassified CRF is harbored among HCV genotype 2, we further focused our search on 142 (4.3%) samples positive for HCV genotype 2. On 116 (81.7%) retrieved samples, the NS5B sequencing was performed. Twelve out of the 116 retrieved samples (10.3%) were classified as CRF 2k/1b by sequencing of the NS5B region. Ten of these 12 samples were originally misclassified as genotype 2a or 2c, while 2 of them were misclassified as genotype 2. Our results show that the current prevalence of CRF 2k/1b is underestimated. The importance of correct HCV genotyping is emphasized, considering the tailored choice of treatment regimen and overall prognosis.  相似文献   
48.
Hox genes are expressed in dynamic patterns during embryogenesis consistent with their role in axial specifications. To study the distribution of mouse Hoxc8, a homeodomain containing protein, we raised monoclonal antibodies against the least conserved portion of Hoxc8. Using these antibodies, we have examined early and mid-gestation embryos for the distribution of the protein. At the end of gastrulation Hoxc8 is expressed in the caudal portion of the embryo. In the neural tube, an early phase when all cells express Hoxc8 is distinguished from a late phase with predominant expression in differentiating neurons. A comparison of this expression pattern with that of a reporter gene under the control of the early Hoxc8 enhancer demarcates three separate regulatory components: (1) initiation and establishment; (2) maintenance; and (3) downregulation. We propose that Hoxc8 expression during embryogenesis is established in multiple phases. Possible regulatory mechanisms involved in generating such a complex domain of Hox gene expression are discussed.  相似文献   
49.
Research has shown that no treatment program designed for street children can succeed unless the community is prepared to respect, protect, and provide opportunities for them (Tacon, cited in Schurink & Rip, 1993). Unfortunately, these children are abused in many parts of the world (Aptekar, 1994). This paper investigates why the general public, as well as those charged with enforcing the law, often treat street children with scorn and hostility.  相似文献   
50.
Thrombopoietin (Mpl ligand), interleukin-6 (IL-6), and interleukin-11 (IL-11) differ in their effects on megakaryocyte maturation and development. In the present study, the impact of these thrombocytopoietic cytokines on biochemical and structural granule and membrane components was examined. Western blotting was performed on equivalent amounts of isolated megakaryocyte or platelet protein and the relative intensities of the enhanced chemiluminescent-visualized bands were quantitated by densitometry. Megakaryocyte growth and development factor (MGDF), a recombinant thrombopoietin-related molecule, significantly increased megakaryocyte fibronectin (72%), thrombospondin (55%), von Willebrand factor (28%) and p-selectin (CD62p) (37%) when compared to equivalent amounts of protein from saline-treated controls (p<0.01). Megakaryocyte fibrinogen was not increased. Ultrastructurally, there was a marked increase in ribosomes and rough endoplasmic reticulum even in mature-appearing megakaryocytes. Platelets from MGDF-treated mice showed small increases in fibronectin (8%), and CD62p (18%), but did not show increases in other measured alpha-granule proteins. Neither IL-6 nor IL-11 increased megakaryocyte or platelet alpha-granule proteins over levels observed in saline controls. IL-11 treated megakaryocytes, while also exhibiting an increase in ribosomes, were characterized by prominent cytoplasmic fragmentation. The study demonstrates the impact of Mpl ligand in increasing synthesized megakaryocyte alpha-granule proteins and of IL-11 in promoting megakaryocyte fragmentation.  相似文献   
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