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91.
JF Cáceres T Misteli GR Screaton DL Spector AR Krainer 《Canadian Metallurgical Quarterly》1997,138(2):225-238
SR proteins are required for constitutive pre-mRNA splicing and also regulate alternative splice site selection in a concentration-dependent manner. They have a modular structure that consists of one or two RNA-recognition motifs (RRMs) and a COOH-terminal arginine/serine-rich domain (RS domain). We have analyzed the role of the individual domains of these closely related proteins in cellular distribution, subnuclear localization, and regulation of alternative splicing in vivo. We observed striking differences in the localization signals present in several human SR proteins. In contrast to earlier studies of RS domains in the Drosophila suppressor-of-white-apricot (SWAP) and Transformer (Tra) alternative splicing factors, we found that the RS domain of SF2/ASF is neither necessary nor sufficient for targeting to the nuclear speckles. Although this RS domain is a nuclear localization signal, subnuclear targeting to the speckles requires at least two of the three constituent domains of SF2/ASF, which contain additive and redundant signals. In contrast, in two SR proteins that have a single RRM (SC35 and SRp20), the RS domain is both necessary and sufficient as a targeting signal to the speckles. We also show that RRM2 of SF2/ASF plays an important role in alternative splicing specificity: deletion of this domain results in a protein that, although active in alternative splicing, has altered specificity in 5' splice site selection. These results demonstrate the modularity of SR proteins and the importance of individual domains for their cellular localization and alternative splicing function in vivo. 相似文献
92.
93.
The Interpersonal Orientation Scale was developed to focus on four dimensions assumed to underlie affiliation motivation: social comparison, emotional support, positive stimulation, and attention. Factor analyses basically supported the proposed multidimensional construct. Evidence for the validity of the four dimensions was provided by their correlations with measures of constructs conceptually related to affiliation motivation and their lack of correlation with measures conceptually unrelated to affiliation motivation. Moreover, in a laboratory study, each motivational subscale tended to correlate most highly with role-played responses in a situation affording the relevant incentive type. Future research on social motivation and interaction will profit from identifying the particular incentives that are salient in a given setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
94.
Immunoglobulin A levels in southern elephant seal (Mirounga leonina) milk during the suckling period
ME Marquez NH Slobodianik PA Ronayne de Ferrer AR Carlini DF Vergani GA Daneri 《Canadian Metallurgical Quarterly》1995,112(3):569-572
Immunoglobulin A (IgA) levels in milk samples from southern elephant seals at King George Island, Antarctica are reported. IgA levels were determined throughout the suckling period (approximately 23 days). The IgA concentration in southern elephant seal milk was lower than in other mammals and, unlike most mammalian milk, was not high during early lactation. There was not a definite pattern in IgA levels, which fluctuated within narrow limits throughout the suckling period (mean +/- SD, 30.81 +/- 6.38 mg IgA/100 g milk). If IgG was present, its level was too low to be detected by the method used. This is the first evidence in Southern elephant seal of the possibility of transmission of passive immunity after birth involving secretion of IgA in the milk. 相似文献
95.
96.
Stress fracture of the sternum is a rare condition which presents as acute anterior chest pain after repetitive upper-body exercise. Two case reports are presented and it is postulated that this is an often underdiagnosed condition which should be considered in the differential diagnosis of acute chest pain in the athlete. Awareness of the injury together with meticulous clinical examination supported by good quality radiographs or isotope bone scan may lead to an increase in the diagnosis of this injury. 相似文献
97.
Multiconductor transmission line theory is used to compare current induced on individual wires within a bundle by injection and radiated excitation. Calculations show that the two types of excitation generally induce significantly different current distributions, but the differences are much smaller for electrically short lines. The results are relevant to the validity of using current injection testing to replace radiated immunity testing 相似文献
98.
99.
AR Elbers PJ Blaauw M de Vries PJ van Gulick OL Smithuis RP Gerrits MJ Tielen 《Canadian Metallurgical Quarterly》1996,18(4):127-131
The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non-practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty-two per cent of the participants were overweight, and relatively more non-practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezing) reported by the vets predominantly working in swine and/or poultry practice could be caused by irritation and/or inflammation of the first part of the trachea-bronchial tree that has no measurable and permanent consequences for changes in lung function or increased bronchial hyperreactivity. The results of a skin test against allergens and determination of allergen-specific IgE in blood indicated that the respiratory complaints were probably not related to allergy against the panel of allergens tested. 相似文献
100.
In comparing our calculated exciton energies with those obtained from pseudopotential calculations (Ref. 27) and from a previous
tight binding calculation (Ref. 30), we stated that the differences between the three semi-empirical calculations arise because
of different treatment of the nanocrystal surfaces. This appears not to be correct. Subsequent calculations with variable
Si-H parameters have shown that the band gap is actually rather insensitive to the actual value of these. Instead, the important
feature appears to be the overall quality of the bulk band structure parameterization. References 27 and 30 use more extensive
and higher quality empirical parameterizations for bulk Si than the sp3s∗ model used by us. Repeating our time dependent calculations with an improved sp3d5 parameterization results in similar values to those of Refs. 27 and 30 for the exciton energies.1 The agreement of the sp3s∗ values with experimental photoluminescence energies (Fig. 7) cannot, therefore, be regarded as well understood at this
time.1,2 相似文献