首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
137Cs and 40K were analyzed in pasture grass and soils throughout a 12-month period. The titanium content of the samples was determined as a marker of soil contamination of the grass samples. The 137Cs activity concentration in the grass was closely correlated with titanium and both increase in the winter months suggesting that increased soil contamination of grass is responsible for the increased 137Cs activity concentration observed at this time. The method greatly overestimates the contribution made by soil to the 137Cs activity concentrations of the grass samples and the results are highly variable. Some problems associated with the method are discussed and it is proposed that this method is unreliable.  相似文献   

2.
3.
Alterations in sexual health caused by inflammatory bowel disease (IBD) may affect quality of life and disease status. IBD usually strikes adolescents or young adults, who are also facing developmental milestones important to sexual health. Issues include growth and development, body image, intimacy and sexual functioning, fertility, and pregnancy. A review of published research regarding these issues, in addition to suggestions for nursing assessment and interventions, is included in this article. Nurses must offer sensitive support and suggestions for coping. Nurses must be aware of the issues influencing sexual health when providing total care to clients with IBD.  相似文献   

4.
5.
The author examines some of the more recent developments in the social and political environments within which the "deregulation fetish" is crucial, but of which it remains only one element. This fetish, as part of a broader assault on the legitimacy of the external regulation of business activity, will not go away; its effects are already being felt in the context of the regulation of occupational safety in the United Kingdom. After outlining recent trends in recorded injuries in U.K. workplaces, with particular reference to manufacturing industries, the author charts the nature and effects of the social and political contexts of the work of U.K. safety regulators in the 1980s. While Thatcher governments withdrew from any direct deregulatory assault on occupational safety, what transpired was a gradual but continual undermining of the ability of these agencies to fulfill their mandated functions. The nature and effects of a new politics of deregulation are examined and this new politics is related to U.K. governmental opposition to European Union influence in domestic social policy, which stands in a symbiotic relationship with the re-emergence of a sustained deregulatory discourse in the United Kingdom.  相似文献   

6.
A methodology for using remotely sensed data to both generate and evaluate a hydraulic model of floodplain inundation is presented for a rural case study in the United Kingdom: Upton-upon-Severn. Remotely sensed data have been processed and assembled to provide an excellent test data set for both model construction and validation. In order to assess the usefulness of the data and the issues encountered in its use, two models for floodplain inundation were constructed: one based on an industry standard one-dimensional approach and the other based on a simple two-dimensional approach. The results and their implications for the future use of remotely sensed data for predicting flood inundation are discussed. Key conclusions for the use of remotely sensed data are that care must be taken to integrate different data sources for both model construction and validation and that improvements in ground height data shift the focus in terms of model uncertainties to other sources such as boundary conditions. The differences between the two models are found to be of minor significance.  相似文献   

7.
8.
9.
10.
11.
12.
T cell tolerance to parenchymal self-antigens is thought to be induced by encounter of the T cell with its cognate peptide-major histocompatibility complex (MHC) ligand expressed on the parenchymal cell, which lacks appropriate costimulatory function. We have used a model system in which naive T cell receptor (TCR) transgenic hemagglutinin (HA)-specific CD4+ T cells are adoptively transferred into mice expressing HA as a self-antigen on parenchymal cells. After transfer, HA-specific T cells develop a phenotype indicative of TCR engagement and are rendered functionally tolerant. However, T cell tolerance is not induced by peptide-MHC complexes expressed on parenchymal cells. Rather, tolerance induction requires that HA is presented by bone marrow (BM)-derived cells. These results indicate that tolerance induction to parenchymal self-antigens requires transfer to a BM-derived antigen-presenting cell that presents it to T cells in a tolerogenic fashion.  相似文献   

13.
The U1 small nuclear ribonucleoprotein particle (snRNP)-specific 70K and A proteins are known to bind directly to stem-loops of the U1 snRNA, whereas the U1-C protein does not bind to naked U1 snRNA, but depends on other U1 snRNP protein components for its association. Focusing on the U1-70K and U1-C proteins, protein-protein interactions contributing to the association of these particle-specific proteins with the U1 snRNP were studied. Immunoprecipitation of complexes formed after incubation of naked U1 snRNA or purified U1 snRNPs lacking their specific proteins (core U1 snRNP) with in vitro translated U1-C protein, revealed that both common snRNP proteins and the U1-70K protein are required for the association of U1-C with the U1 snRNP. Binding studies with various in vitro translated U1-70K mutants demonstrated that the U1-70K N-terminal domain is necessary and sufficient for the interaction of U1-C with core U1 snRNPs. Surprisingly, several N-terminal fragments of the U1-70K protein, which lacked the U1-70K RNP-80 motif and did not bind naked U1 RNA, associated stably with core U1 snRNPs. This suggests that a new U1-70K binding site is generated upon association of common U1 snRNP proteins with U1 RNA. The interaction between the N-terminal domain of U1-70K and the core RNP domain was specific for the U1 snRNP; stable binding was not observed with core U2 or U5 snRNPs, suggesting essential structural differences among snRNP core domains. Evidence for direct protein-protein interactions between U1-specific proteins and common snRNP proteins was supported by chemical crosslinking experiments using purified U1 snRNPs. Individual crosslinks between the U1-70K and the common D2 or B'/B protein, as well as between U1-C and B'/B, were detected. A model for the assembly of U1 snRNP is presented in which the complex of common proteins on the RNA backbone functions as a platform for the association of the U1-specific proteins.  相似文献   

14.
15.
The method of successive intervals is compared with respondents' estimates of how much they would pay for a series of objects, as measures of object preference. It is argued that "the principle that consumers make purchases at those points on their buying continuum where marginal preferences are equal assumes that preferences measured for articles of different costs are based upon the same sized measuring unit." The method of successive intervals or other method based on a judgmental error unit calls for a correction when the range in preference variation is large, and the monetary estimates can be used to provide such a correction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
OBJECTIVES AND DESIGN: A prospective study of 709 patients undergoing carotid surgery in the U.K. and Ireland was performed to evaluate the performance of vascular surgeons. MATERIALS AND METHODS: Fifty-nine surgeons (range 2-39 cases each) were sampled and all patients undergoing surgery over a 6-month period (1 March 1994-31 August 1994) were included in the study. Indications for surgery were TIA (35.9%), AF (23.3%), CVA (21.4%) and "others" (19.6%). RESULTS: Mean ipsilateral stenosis was 82% (30%-99%). Thirty-one percent of patients had preoperative neurological consults. Shunts were used in 67.6%, tacking sutures in 40.1%, drains in 71.9% and patches in 54.4% of cases. At 30 days there were nine (1.3%) deaths (four cardiac, three neurological). There were 15 ipsilateral postoperative CVAs (2.1%); 19% of patients had one or more complication, usually minor. Statistical analysis showed no independent risk factor for CVA other than seniority of the surgeon. CONCLUSIONS: A combined stroke/death rate of 3% for the series was obtained at 30 days for all cases. This large, validated study suggests that members of the Vascular Society of G.B. and Ireland currently have a very low morbidity/mortality rate for performing carotid surgery. Continued audit is required to ensure that this quality of service does not deteriorate.  相似文献   

17.
18.
BACKGROUND: The number of patients waiting lung transplantation greatly exceeds the supply of donors. This study was conducted to determine the effect of high-dose steroid administration on oxygenation and donor lung recovery after brain death. METHODS: A retrospective analysis was conducted on 118 consecutive organ donors from January 1 through December 31, 1995. Eighty donors received high-dose steroids (methylprednisolone, mean 14.5+/-0.06 mg/kg) after organ procurement organization management began; a second group was composed of 38 patients who received no steroids. PaO2/FiO2 ratios were used to evaluate oxygenation. The number of single and double lungs transplanted served as the endpoint. RESULTS: No differences were noted in hemodynamics, most clinical or demographic variables and initial values of PaO2/FiO2 between groups. However, nonsteroid-treated donors showed an overall decrease in oxygenation (mean decrease in PaO2/FiO2 -34.2+/-14), whereas steroid-treated donors had a significant and progressive increase in oxygenation (mean increase in PaO2/FiO2: 16+/-14) before aortic cross-clamping (p = 0.01). Time before cross-clamping was longer in the steroid-treated patients (p = 0.003). The number of procured lungs was markedly greater in steroid-treated than nonsteroid-treated donors (25/80 patients vs 3/38; p < 0.01). CONCLUSIONS: High-dose methylprednisolone given during donor management results in improved oxygenation at organ recovery. This treatment resulted in a significant increase in the number of lungs transplanted and may have enabled donors to be treated longer.  相似文献   

19.
20.
The last two amino acids in the nascent peptide influence translation termination in E. coli (Mottagui-Tabar et al., 1994; Bj?rnsson et al., 1996). We have compared the effects on termination in Escherichia coli, Bacillus subtilis and Salmonella typhimurium obtained by varying the -1 and -2 codons upstream of the weak UGAA stop signal. The peptide effect from the penultimate amino acid on translation termination in B. subtilis is similar to that seen in E. coli (with 66.5% RF-2 amino acid sequence similarity), whereas the influence in S. typhimurium (with 95.3% similarity to E. coli) is weaker. The effect of changing the -1 codon (P-site) is weaker in S. typhimurium as compared to those in E. coli and B. subtilis. RF-2s from E. coli and S. typhimurium have a threonine or alanine at position 246, respectively. This amino acid exchange in RF-2 can explain the difference in efficiency and toxicity during overexpression when E. coli and S. typhimurium are compared (Uno et al., 1996). However, B. subtilis RF-2 also has an alanine at that position, yet the sensitivity to the nascent peptide is similar to that in E. coli. Thus, the amino acid difference at position 246 in the RF-2 sequences cannot explain why termination in E. coli and B. subtilis is similar in peptide sensitivity while being different from that in S. typhimurium. Sequence alignments of RF-2 from the three bacteria show other regions of the molecule that could be involved in the functional interactions with the C-terminal end of the nascent peptide.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号