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1.
We present a comprehensive structural, evolutionary and molecular dynamics (MD) study of the G/U wobble basepairs in the ribosome based on high-resolution crystal structures, including the recent Escherichia coli structure. These basepairs are classified according to their tertiary interactions, and sequence conservation at their positions is determined. G/U basepairs participating in tertiary interactions are more conserved than those lacking any interactions. Specific interactions occurring in the G/U shallow groove pocket--like packing interactions (P-interactions) and some phosphate backbone interactions (phosphate-in-pocket interactions)--lead to higher G/U conservation than others. Two salient cases of unique phylogenetic compensation are discovered. First, a P-interaction is conserved through a series of compensatory mutations involving all four participating nucleotides to preserve or restore the G/U in the optimal orientation. Second, a G/U basepair forming a P-interaction and another one forming a phosphate-in-pocket interaction are replaced by GNRA loops that maintain similar tertiary contacts. MD simulations were carried out on eight P-interactions. The specific GU/CG signature of this interaction observed in structure and sequence analysis was rationalized, and can now be used for improving sequence alignments.  相似文献   
2.
Objective: To examine the relationship between self‐reported body mass index (BMI) and health‐related quality of life in the general adult population in the United States. Research Methods and Procedures: Using data from 109,076 respondents in the 1996 Behavioral Risk Factor Surveillance System, we examined how self‐reported BMI is associated with five health‐related quality of life measures developed by the Centers for Disease Control and Prevention for population health surveillance. Results: After adjusting for age, gender, race or ethnicity, educational attainment, employment status, smoking status, and physical activity status, participants with a self‐reported BMI of <18.5 kg/m2 and participants with a self‐reported BMI of ≥30 kg/m2 reported impaired quality of life. Compared with persons with a self‐reported BMI of 18.5 to <25 kg/m2, odds ratios (ORs) of poor or fair self‐rated health increased among persons with self‐reported BMIs of <18.5 (1.57, 95% confidence interval [CI]: 1.31 to 1.89), 25 to <30 kg/m2 (1.12, 95% CI: 1.04 to 1.20), 30 to <35 kg/m2 (1.65, 95% CI: 1.50 to 1.81), 35 to <40 kg/m2 (2.58, 95% CI: 2.21 to 3.00), and ≥40 kg/m2 (3.23, 95% CI: 2.63 to 3.95); ORs for reporting ≥14 days of poor physical health during the previous 30 days were 1.44 (95% CI: 1.21 to 1.72), 1.04 (95% CI: 0.96 to 1.14), 1.32 (95% CI: 1.19 to 1.47), 1.80 (95% CI: 1.52 to 2.13), and 2.37 (95% CI: 1.90 to 2.94), respectively; ORs for having ≥14 days of poor mental health during the previous 30 days were 1.18 (95% CI: 0.97 to 1.42), 1.02 (95% CI: 0.95 to 1.11), 1.22 (95% CI: 1.10 to 1.36), 1.68 (95% CI: 1.42 to 1.98), and 1.66 (95% CI: 1.32 to 2.09), respectively. Discussion: In the largest study to date, low and increased self‐reported BMI significantly impaired health‐related quality of life. Particularly, deviations from normal BMI affected physical functioning more strongly than mental functioning.  相似文献   
3.
The complex [Fe(III)(salten)(mepepy)]BPh4 (salten = 4-azaheptamethylene-1,7-bis(salicylideneiminate; mepepy = 1-(pyridin-4-yl)-2-(N-methylpyrrol-2-yl)-ethene; BPh4 = tetraphenyl borate) has been investigated to determine the volume and enthalpy changes associated with the room temperature photo-induced spin crossover. Here we report the photophysical properties of the trans to cis isomerization of the mepepy ligand as well as the spin crossover of the Fe(III)(salten)(mepepy) complex in acetonitrile:water mixtures using photoacoustic calorimetry (PAC). The PAC studies indicate that the trans to cis transition of the mepepy ligand occurs faster than the ∼20 ns response time of the acoustic detector and gives rise to a negligible volume change (0.7 ± 0.3 mL mol−1) and an enthalpy change of 33 ± 10 kcal mol−1. These results are consistent with the loss of a charge assisted hydrogen bond between a water molecule and the pyridyl ring of the mepepy upon photoisomerization. In the case of Fe(III)(salten)(mepepy) photoexcitation, PAC results indicate that the high-spin to low-spin transition, also occurring in ?20 ns, gives rise to small volume and enthalpy changes (0.9 mL mol−1 and 4 kcal mol−1). Analysis of the results indicate that the observed thermodynamics are related to a distortion of the Fe(II)(salten)(mepepy) complex associated with the cleavage of an Fe?N bond upon spin conversion.  相似文献   
4.
Objective: To examine the variation in the prevalences of obesity and type 2 diabetes in weight loss counseling by health providers and in other potential obesity‐related determinants in 100 metropolitan statistical areas in the United States. Research Methods and Procedures: We performed a cross‐sectional study using data from the 2000 Behavioral Risk Factor Surveillance System, the largest telephone survey of health behaviors in the United States, of age‐adjusted prevalence of obesity, type 2 diabetes, intake of ≥five servings of fruits and vegetables per day, participation in 150 minutes of leisure‐time physical activity per week, receipt of weight management advice, and reports of trying to lose or maintain weight among men and women more than 18 years old. Results: The age‐adjusted prevalence of obesity ranged from 13.1% to 30.0% and that of type 2 diabetes from 3.3% to 9.2%. Among participants who had visited a physician for a routine checkup in the previous 12 months, 13.1% to 27.1% of all participants recalled receiving advice from a health professional about their weight, and 11.7% to 34.6% of overweight or obese participants recalled receiving advice to maintain or lose weight. Discussion: Significant differences in the prevalence of obesity and self‐reported type 2 diabetes and in medical practice patterns regarding weight management advice exist among metropolitan statistical areas. These results suggest important opportunities to investigate reasons for these variations that could potentially be used to mitigate the current epidemic of obesity and to identify areas where obesity and diabetes prevention efforts may need to be targeted.  相似文献   
5.
Metallothioneins and resistance to cadmium poisoning in Drosophila cells   总被引:5,自引:0,他引:5  
Toxicity of cadmium on Drosophila cell lines has been studied. Maximal tolerance for cadmium chloride is 10 microM. Metallothioneins are induced in Drosophila cells following cadmium addition. A stable cadmium resistant cell line (Cd R200) has been selected starting from the haploid D clone. The Cd R200 cells are diploid and display metallothionein levels 22 times higher than cells of the original line fully induced with cadmium. The 200 microM CdCl2 tolerance upper limit in Cd R200 line is overcome if L-cysteine is supplemented to the medium. It is thus possible, in the presence of 5 mM L-cysteine, to select cells able to resist 800 microM CdCl2. These cells produce 4 times more metallothioneins than Cd R200 cells.  相似文献   
6.
7.
Indigenous women in Mesoamerica experience disproportionately high maternal mortality rates and are less likely to have institutional deliveries. Identifying correlates of institutional delivery, and satisfaction with institutional deliveries, may help improve facility utilization and health outcomes in this population. We used baseline surveys from the Salud Mesoamérica Initiative to analyze data from 10,895 indigenous and non-indigenous women in Guatemala and Mexico (Chiapas State) and indigenous women in Panama. We created multivariable Poisson regression models for indigenous (Guatemala, Mexico, Panama) and non-indigenous (Guatemala, Mexico) women to identify correlates of institutional delivery and satisfaction. Compared to their non-indigenous peers, indigenous women were substantially less likely to have an institutional delivery (15.2% vs. 41.5% in Guatemala (P<0.001), 29.1% vs. 73.9% in Mexico (P<0.001), and 70.3% among indigenous Panamanian women). Indigenous women who had at least one antenatal care visit were more than 90% more likely to have an institutional delivery (adjusted risk ratio (aRR) = 1.94, 95% confidence interval (CI): 1.44–2.61), compared to those who had no visits. Indigenous women who were advised to give birth in a health facility (aRR = 1.46, 95% CI: 1.18–1.81), primiparous (aRR = 1.44, 95% CI: 1.24–1.68), informed that she should have a Caesarean section (aRR = 1.41, 95% CI: 1.21–1.63), and had a secondary or higher level of education (aRR = 1.36, 95% CI: 1.04–1.79) also had substantially higher likelihoods of institutional delivery. Satisfaction among indigenous women was associated with being able to be accompanied by a community health worker (aRR = 1.15, 95% CI: 1.05–1.26) and facility staff speaking an indigenous language (aRR = 1.10, 95% CI: 1.02–1.19). Additional effort should be exerted to increase utilization of birthing facilities by indigenous and poor women in the region. Improving access to antenatal care and opportunities for higher-level education may increase institutional delivery rates, and providing culturally adapted services may improve satisfaction.  相似文献   
8.
9.
RNA atomic resolution structures have revealed the existance of different families of basepair interactions, each of which with its own isosteric sub-families. Ribostral (Ribonucleic Structural Aligner) is a user-friendly framework for analyzing, evaluating and viewing RNA sequence alignments with at least one available atomic resolution structure. It is the first of its kind that makes direct and easy- to-understand superposition of the isostericity matrices of basepairs observed in the structure onto sequence alignments, easily indicating allowed and unallowed substitutions at each BP position. Potential mistakes in the alignments can then be corrected using other sequence editing software. Ribostral has been developed and tested under Windows XP, and is capable of running on any PC or MAC platform with MATLAB 7.1 (SP3) or higher installed version. A stand-alone version is also available for the PC platform. AVAILABILITY: http://rna.bgsu.edu/ribostral.  相似文献   
10.
In this paper, we propose bounding models, which provide upper and lower bounds on response time in composite Web service model, for alleviating the state explosion problem. The considered models have heterogeneous servers and the number of elementary Web services can be very large. More precisely, we study two types of composite Web services. First, we investigate the performance of a single composite Web service execution instance. Second, this assumption is relaxed (i.e. multiple composite Web services execution instances are considered). These models allows to find trade-off between the accuracy of the bounds and the computation complexity.  相似文献   
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