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1.
Most eukaryotic mRNAs contain a 5' cap (m7GppX) and a 3' poly(A) tail to increase synergistically the translational efficiency. Recently, the poly(A) binding protein (PABP) and cap-binding protein, eIF-4F, were found to interact [Le et al. (1997) J. Biol. Chem. 272, 16247-16255; Tarun and Sachs (1996) EMBO J. 15, 7168-7177]. These data suggest that PABP may exert its effect on translational efficiency either by increasing the formation of initiation factor-mRNA complex or by enhancing ribosome recycling. To investigate the functional consequences of these interactions, the fluorescent cap analogue, ant-m7GTP, which is an environmentally sensitive fluorescent probe [Ren and Goss (1996) Nucleic Acids Res. 24, 3629-3634] was used to investigate the cap-binding affinity. Our data show that the binding of eIF-(iso)4F or eIF-4F to cap analogue enhanced their binding affinity toward PABP approximately 40-fold. Similarly, the eIF-4F/PABP or eIF-(iso)4F/PABP complexes show a 40-fold enhancement of cap analogue binding as compared to eIF-4F or eIF-(iso)4F alone. At least part of the enhancement of the translational initiation by PABP can be accounted for by direct changes in cap-binding affinity. The interactions of these components also suggest a mechanism whereby the poly(A) tail is brought into close proximity with m7G cap. This effect was examined by fluorescence energy transfer, and it was determined that the PABP/eIF-4F complex could bind both poly(A) and 5' cap simultaneously.  相似文献   

2.
Administered parallel forms of a logical game situation to 40 intelligent students in each of Grades 6, 8, 10, and 12. The "Butch and Slim Game" and the "Shape Game," differed mainly in that reported speech was used in the former. The Shape Game proved easier at each grade level. This was attributed to several uncontrolled sources of variation in format. There was also evidence of significant age and sex differences in performance. Examination of individual items did not reveal pronounced developmental trends in difficulty levels. Items involving implicatory reasoning and operations of negation are examined in detail. It is concluded that formal logic possesses considerable limitations as a rationale for the construction of psychometric instruments. (French summary) (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

3.
Computed discrepancy scores (multiple regression equations using IQs from the Slosson Intelligence Test, SES, sex, and age of child to predict reading and math achievement raw scores) and an unadjusted low-achievement criterion (discrepancy between achievement and potential) for 218 1st graders from normal classrooms in 6 rural elementary schools. In addition to determining the predictor variables already mentioned, the authors also administered the Behavior Problem Checklist, the Bender Visual Motor Gestalt Test for Children, the Visual Matching subtest of the Metropolitan Readiness Test, Level I—Form P, the Wepman Auditory Discrimination Test, and measures of audio-visual integration, handedness, finger localization, finger tapping, lateral dominance, letter and number recognition, motor coordination, name writing, and quantitative concepts. A rating of academic performance was obtained from each teacher. Data show that unadjusted low-achievement criteria misidentified as learning disabled (LD) a significant number of Ss who were achieving at levels commensurate with overall abilities, while failing to identify a significant number of truly LD children. Many of the variables that significantly discriminated low achievers from high achievers did not significantly discriminate LD from non-LD children. (68 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

4.
PURPOSE: To evaluate two smoking-cessation practice exercises, one using standardized patients (SPs), the other using role playing by medical students. METHOD: In the spring of 1994 all 120 first-year University of California, San Francisco, School of Medicine Students were given lectures on the health effects of smoking and how physicians can help patients quit. Afterward some of the students were randomly assigned to two groups in which to practice counseling patients: Group 1 (n = 35) used SPs, Group 2 (n = 37) used role playing. Each of the Group 1 students practiced smoking-cessation techniques with an SP; the SP evaluated the student on cognitive and communication skills, assigned an overall rating, and provide feedback using a standardized form. The Group 2 students (as well as the 48 students not assigned to a group) role-played in pairs and used the same form to provide feedback. All the students evaluated their respective practice practices. Two weeks later 24 Group 1 and 31 Group 2 students participated in a clinic-skills-assessment exercise using SPs. As in the Group 1 practice exercise, each student was evaluated by an SP on cognitive and communication skills and assigned an overall rating. Data were analyzed through a number of statistical methods. The cost of the SP program was determined. RESULTS: The Group 1 students rated their practice exercise much more favorably than did the Group 2 students. However, there was no significant difference between the groups in their ratings by the SPs on the clinical-skills-assessment exercise. The use of SPs cost a great deal more than did the use of role playing. CONCLUSION: Although the students rated the SPs higher than they did the role playing, the two tools produced similar levels of skills attainment. The data suggest that having students practice smoking-cessation techniques through role playing may be as effective as using the more extensive SPs.  相似文献   

5.
Human plasma acetate is derived from colonic fermentation of fiber and endogenous metabolism of dextrose and fatty acids. Acetate may have regulatory functions in hepatic carbohydrate metabolism. Intake of dietary fiber is associated with several beneficial effects on carbohydrates and lipids metabolisms. To study theses effects a valid and automated method for routine analysis of acetate in plasma is necessary. After oral administration of lactulose to healthy human volunteers, the concentration of plasma acetate was measured by head space gas chromatography (HS-GC), vacuum distillation gas chromatography (VD-GC) and enzymatic spectrometric method (ES). The method HS-GC was linear to 0.5 mmol.l-1 (n = 5, r = 0.998), the detection limit is 0.005 mmol.l-1. Within-day variation (CV) was 3.60% and day-to-day variation was 4.5% (0.1 mmol.l-1). The coefficients of correlation between CG-ET/CG-DsV and CG-ET/E-M are 0.903 (p = 0.0001) and 0.54 (p = 0.006) respectively, the mean square errors are respectively 0.118 and 0.138 mmol.l-1. The variation curves of plasma acetate measured by GC versus time show peak concentration of 0.323 to 0.380 mmol.l-1 at 120 min.  相似文献   

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7.
A total of 154 Ss viewed under tachistoscopic exposure the 45 pairs of 10 ads, and indicated which ad of each pair they would look at again. The mean number of preferences were correlated with two eye-camera measures (number of first looks and number of seconds spent looking.) The reliability of the paired-comparison tachistoscopic method was .99; it correlated .86 and .99 with the eye measures. "In situations where eye-movement photography could be used… the results… indicate that a considerable saving of time and energy can be effected by use of a… tachistoscopic presentation." (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

8.
In the last years, the occurrence of pesticides and other chemicals in groundwater has been confirmed. The herbicide atrazine is among the pesticides most frequently detected in groundwater. In groundwater samples from the United States atrazine concentrations reached levels up to 10 micrograms/1. In our lysimeter experiments with radioactive labelled terbuthylazine we measured 2.87-4.20% of the applied radioactivity after 1160 days in the leachate.  相似文献   

9.
BACKGROUND: The diagnosis of skin disease by histologic examination is regarded as the reference standard upon which therapy and follow-up are determined. Our study investigated the reliability of skin biopsy diagnosis requested by family physicians and physicians' assistants. METHODS: Biopsy diagnoses by a community-based pathology group were reinterpreted by our study dermatopathologist on a sample of 119 skin biopsies randomly selected from the 1844 biopsies performed by family physicians and physicians' assistants at a large Washington State health maintenance organization during a 4 1/2-year period. RESULTS: There were 107 exact matches and 3 mismatches of premalignant lesions and 6 mismatches of benign diagnoses. In addition, two melanomas diagnosed by the community-based pathologists were interpreted as benign by our study dermatopathologist. A third melanoma diagnosed by the community-based group was interpreted as a poorly differentiated squamous cell cancer by the university dermatopathologist. The weighted kappa, 0.83, indicated excellent interrater agreement. CONCLUSION: Although our study showed excellent interrater concordance of skin biopsy interpretation, there was disagreement about three melanomas between a community-based general pathology group and our study dermatopathologist. The melanoma disagreement is consistent with previous studies that found poor interrater agreement for early melanomas. The community-based pathologists were uncertain about two of these melanomas, and as part of their quality control and review procedures requested confirmation by an expert pathologist, who agreed with the melanoma diagnosis. Family physicians are justified in requesting a second opinion (if not automatically requested by a community laboratory) when the histopathologic diagnosis is not in concordance with the clinical history or impression or when the pathologist is unsure of the diagnosis.  相似文献   

10.
The purpose of this study is to investigate the effects of endotoxin on human in vitro fertilization and embryo transfers (IVF-ET) and to evaluate a quality control system for a culture medium using endotoxin assays. Before the final water purification (in an ultra-pure water system with a depyrogen filter) of the medium, the sources of water were pre-purified as follows; (I) distillation-->deionization x 2, (II) distillation-->ultra-pure water system or (III) reverse osmosis system. The limulus amebocyte lysate gelation tests (sensitivities of 0.03 and 0.25EU/ml) were used to detect endotoxin in the medium and in pre-purified water (pre-water). No pregnancies occurred in the endotoxin-positive medium (endotoxin > or = 0.03EU/ml). The endotoxin-negative medium resulted in a 33.3% pregnancy rate and 13.4% implantation rate. No statistical differences in the implantation rate were found among these methods of pre-purification (I: 12.5%, II: 13.4% and III: 20.0%). Endotoxin was detected in all the pre-water between 0.25 and 4.0EU/ml. The clinical pregnancy rate (36.6%) and the implantation rate (16.9%) in pre-water of endotoxin < 0.25EU/ml were significantly higher than those (10.5% and 5.5%) in pre-water of endotoxin > or = 0.25EU/ml (p < 0.05). We confirmed that a very low concentration of endotoxin disturbed a human embryo implantation. Endotoxin assays, not only in the media, but also in pre-water before final purification are useful as a quality control for the IVF-ET program.  相似文献   

11.
The aim of this study was to investigate whether in the maxilla and in the mandible the structure of the anterior medial sagittal alveolar and basal bone is related to the overbite. A total of 460 untreated adult subjects were divided into four groups with either deep bite, normal overbite, end-to-end bite, or open bite and were compared. The overbite, lower face height, and anterior alveolar and basal midsagittal cross-sectional areas from the maxilla and the mandible were assessed on lateral cephalometric radiographs. An index was calculated, dividing the sagittal by the vertical dimension of the midsagittal cross-sectional area. A deeper bite coincided with smaller lower face height, larger alveolar and basal areas, and a more widened shape of the symphysis. If the lower face height was introduced as a covariable, the open bite group showed significantly smaller maxillary and mandibular alveolar and basal cross-sectional areas compared with the end-to-end group, the normal overbite group, or the deep bite group. Vertical variation of the overbite probably coincides with a relative hyperdevelopment or hypodevelopment of the symphysis.  相似文献   

12.
The effects of chemical (CD) and surgical (SD) deafferentation of the cerebellum on different steps of the metabolism of thiamine (Th), thiamine monophosphate (ThMP) and thiamine pyrophosphate (ThPP) were evaluated in vivo in rats. CD was carried out by i.p. injection of 3-acetylpyridine, followed by harmaline and niacinamide. SD was carried out by complete dissection of the peduncles of the left cerebellar hemisphere. Under steady state condition the radioactivity of Th and its phosphoesters was determined in plasma and whole cerebellum after an i.p. injection of thiazole-[2(14)C]-thiamine (30 micrograms:1.25 micro Ci). Analytical data were processed by using an improved mathematical compartmental model, which allowed the calculation of fractional rate constants (FRC), turnover rates (TR) and turnover times (TT). Both CD and SD caused a significant reduction of TR values for Th phosphorylation to ThPP, dephosphorylation of ThPP to ThMP and Th, and ThMP, but not Th, release. TT for all Th compounds were increased compared to controls, indicating a general slowing of thiamine metabolism in the deafferented cerebellum. These results indicate an imbalance in the thiamine metabolism resulting from the impaired activity of cerebellar neurons. The possible implications of the changes in rate of Th compound turnover with respect to biochemical changes in cerebellar ataxia are discussed.  相似文献   

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14.
The paper presents the application of hidden Markov models (HMM) in the analysis of the linguistic microdifferentiation of 48 reproductively isolated populations in the Eastern Adriatic. The mathematical method is described in detail when applied for the recognition of the two main dialects (cakavian and stokavian) present in the investigated area, using two distinguished HMM. The resulting classification of villages is compared to those of the clustering methods applied previously for the same purpose.  相似文献   

15.
Based on data on 9 tests for 2 samples of Navy trainees (N = 184, 176) the Wherry-Doolittle Test Selection Technique was compared with a short-cut method proposed by Jenkins, using a table. The composite r between Grade Point Average and the predicted composite for the Wherry-Doolittle method was .648, while that for Jenkin's method was .646. Jenkin's method takes one-fifth to one-eighth less time than the Wherry-Doolittle. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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17.
"Improvement in performance with training in a complex task of radar air traffic control was compared under a condition of constant high input load during training vs. a condition of graduated input load during training… . The test performance of Ss trained under constant high input load was significantly superior on several criteria to that of Ss trained under the graduated input load condition." From Psyc Abstracts 36:04:4LE65K. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

18.
The tensile properties of SCS-6 SiC fiber-reinforced Ti-24Al-11Nb (at. pct) have been measured over the past several years by a number of investigators. These composites have been fabricated by different techniques and tend to exhibit a large amount of scatter in the longitudinal tensile properties. To date, it is not known if one optimized fabrication method provides composites with improved mechanical properties over those produced by other optimized methods, since carefully controlled experiments have not been performed to determine this. Thus, the purpose of the present study was to compare the longitudinal tensile strengths of SCS-6 SiC/ Ti-24Al-11Nb composites that had been fabricated by the powder-cloth method and the lowpressure plasma spray (LPPS) method. In this study, the same lots of matrix powder and reinforcing fiber were used for fabricating the composites. It was determined that the powder-cloth and plasma spray methods produced composites having very similar tensile properties. Both fabrication methods induced damage in a small percentage of fibers, which manifested itself in the form of bimodal Weibull distributions of extracted fiber strengths. It appeared that the particular lot of SCS-6 fiber used in fabricating both types of composites was more susceptible to fabrication damage than those used in previous studies. This article also shows the dramatic effect that different handling and testing techniques can have on measured fiber strengths.  相似文献   

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20.
In the study reported in this article, the researchers attempted to raise awareness among practitioners of the importance of intramuscular drug administration technique in reducing injection site complications following antipsychotic depot injections. They also aimed to improve and expand the scope of present practice by comparing the effect of two accepted techniques, the 'air bubble' and 'Z-track' on these complications, and demonstrate that the air bubbles technique is more effective in reducing seepage and causes less discomfort. A 'within subjects' design was used, and Likert scales for scoring subjective and objective assessment of complications were established and scored at each injection. The study showed that there was no significant difference between the effects of either technique.  相似文献   

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