753 resultados para Human Physiological Performance.


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The DO experiment at Fermilab's Tevatron will record several petabytes of data over the next five years in pursuing the goals of understanding nature and searching for the origin of mass. Computing resources required to analyze these data far exceed capabilities of any one institution. Moreover, the widely scattered geographical distribution of DO collaborators poses further serious difficulties for optimal use of human and computing resources. These difficulties will exacerbate in future high energy physics experiments, like the LHC. The computing grid has long been recognized as a solution to these problems. This technology is being made a more immediate reality to end users in DO by developing a grid in the DO Southern Analysis Region (DOSAR), DOSAR-Grid, using a available resources within it and a home-grown local task manager, McFarm. We will present the architecture in which the DOSAR-Grid is implemented, the use of technology and the functionality of the grid, and the experience from operating the grid in simulation, reprocessing and data analyses for a currently running HEP experiment.

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A polymer analogous synthesis involving the reductive amination of phosphorylcholine (PC)-glyceraldehyde with primary amines of deacetylated chitosan (M-w approximate to 57000 g mol(-1)) was used to prepare phosphorylcholine-substituted chitosans (PC-CH) with a degree of substitution (DS) ranging from similar to 11 to similar to 53 mol% PC-substituted glucosamine residues. The PC-CH derivatives were characterized by H-1 NMR spectroscopy, FTIR spectroscopy, and multiangle laser light scattering gel permeation chromatography (MALLS-GPC). The pKa of the PC-substituted amine groups (pKa approximate to 7.20) was determined by H-1 NMR titration. The PC-CH samples (1.0 g L-1) were shown to be nontoxic using an MTT assay performed with human KB cells. Aqueous solutions of PC-CH samples (4.0 g L-(1)) of DS g 22 mol% PC-substituted glucosamine residues remained clear, independently of pH (4.0 < pH < 11.0). The remarkable water solubility and nontoxicity displayed by the new PC-CH samples open up new opportunities in the design of chitosan-based biomaterials and nanoparticles.

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Nobiletin (NOB) and tangeretin (TAN), two of the main polymethoxylated flavones (PMFs) in citrus, influence a number of key biological pathways in mammalian cells. Although the impacts of NOB and TAN on glucose homeostasis and cholesterol regulation have been investigated in human clinical trials, much information is still lacking about the metabolism and oral bioavailability of these compounds in animals. In this study, NOB and TAN were administered to rats by gavage and intraperitoneal (ip) injection, and the blood serum concentrations of these compounds and their main metabolites were monitored by high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS). In addition to the administered compounds, two metabolites of TAN and eight metabolites of NOB were detected and measured over 24 h. With identical oral doses, nearly 10-fold higher absorption of NOB occurred compared to TAN. For both compounds, maximum levels of glucuronidated metabolites occurred in the blood serum at later time points (similar to 5-8 h) compared to the earlier T(max) a values for NOB and TAN. In most cases the glucuronides occurred at substantially higher concentrations than the aglycone metabolites. Low levels of NOB and TAN and their metabolites were detectable in rat blood serum even at 24 h after treatment.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The serological detection of antibodies against human papillomavirus (HPV) antigens is a useful tool to determine exposure to genital HPV infection and in predicting the risk of infection persistence and associated lesions. Enzyme-linked immunosorbent assays (ELISAs) are commonly used for seroepidemiological studies of HPV infection but are not standardized. Intra-and interassay performance variation is difficult to control, especially in cohort studies that require the testing of specimens over extended periods. We propose the use of normalized absorbance ratios (NARs) as a standardization procedure to control for such variations and minimize measurement error. We compared NAR and ELISA optical density (OD) values for the strength of the correlation between serological results for paired visits 4 months apart and HPV-16 DNA positivity in cervical specimens from a cohort investigation of 2,048 women tested with an ELISA using HPV-16 virus-like particles. NARs were calculated by dividing the mean blank-subtracted (net) ODs by the equivalent values of a control serum pool included in the same plate in triplicate, using different dilutions. Stronger correlations were observed with NAR values than with net ODs at every dilution, with an overall reduction in nonexplained regression variability of 39%. Using logistic regression, the ranges of odds ratios of HPV-16 DNA positivity contrasting upper and lower quintiles at different dilutions and their averages were 4.73 to 5.47 for NARs and 2.78 to 3.28 for net ODs, with corresponding significant improvements in seroreactivity-risk trends across quintiles when NARs were used. The NAR standardization is a simple procedure to reduce measurement error in seroepidemiological studies of HPV infection.

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The objectives of this study were to verify the effects of wet suits (WS) on the performance during 1500m swimming (V1500), on the velocity corresponding to the anaerobic threshold (VAT) and on the drag force (AD) as well as its coefficient (Cx). 19 swimmers randomly completed the following protocols on different days (with and without WS): 1) maximal performance of 1500m swimming; 2) VAT in field test, with fixed concentration of blood lactate (4 mM) and 3) determination of hydrodynamic indices (AD and Cx). The results demonstrated significant differences (p < 0.05) in the VAT (1.27±0.09; 1.21±0.06 m.s-1), and in the V1500 (1.21±0.08; 1.17±0.08 m.s-1), with and without WS, respectively. However the AD, and its Cx did not present significant differences (p>0.05) for the respective maximal speeds of swimming. In summary, we can conclude that WS allows swimmers to reach greater speeds in both, long- and short-course swims. This improvement can be related to the decrease of the AD, since with higher speeds (with WS) the subjects presented the same resistance, as they did when compared to speeds without a WS. Moreover, these data suggest that the methodology used in this study to determine the Cx is unable to detect the improvement caused by WS.

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Responses of net photosynthetic rates to temperature, irradiance, pH/inorganic carbon and diurnal rhythm were analyzed in 15 populations of eight freshwater red algal species in culture and natural conditions. Photosynthetic rates were determined by oxygen concentration using the light and dark bottles technique. Parameters derived from the photosynthesis-irradiance curves indicated adaptation to low irradiance for all freshwater red algae tested, confirming that they tend to occur under low light regimes. Some degree of photoinhibition (β = -0.33-0.01 mg O2 g-1 DW h-1 (μmol photons m-2 s-1)-1) was found for all species/populations analyzed, whereas light compensation points (lc) were very low (≤ 2 μmol photons m- photons s-1) for most algae tested. Saturation points were low for all algae tested (lk = 6-54 μmol photons m-2 S-1; lS = 20-170 μmol photons m-2 s-1). Rates of net photosynthesis and dark respiration responded to the variation in temperature. Optimum temperature values for net photosynthesis were variable among species and populations so that best performances were observed under distinct temperature conditions (10, 15, 20 or 25°C). Rates of dark respiration exhibited an increasing trend with temperature, with highest values under 20-25°C. Results from pH experiments showed best photosynthetic performances under pH 8.5 or 6.5 for all but one species, indicating higher affinity for inorganic carbon as bicarbonate or indistinct use of bicarbonate and free carbon dioxide. Diurnal changes in photosynthetic rates revealed a general pattern for all algae tested, which was characterized by two relatively clear peaks, with some variations around it: a first (higher) during the morning (07.00-11.00 hours.) and a second (lower) in the afternoon (14.00-18.00 hours). Comparative data between the 'Chantransia' stage and the respective gametophyte for one Batrachospermum population revealed higher values (ca 2-times) in the latter, much lower than previously reported. The physiological role of the 'Chantransia' stage needs to be better analyzed.

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Purine nucleoside phosphorylase (PNP) catalyzes the phosphorolysis of the N-ribosidic bonds of purine nucleosides and deoxynucleosides. A genetic deficiency due to mutations in the gene encoding for human PNP causes T-cell deficiency as the major physiological defect. Inappropriate activation of T-cells has been implicated in several clinically relevant human conditions such as transplant tissue rejection, psoriasis, rheumatoid arthritis, lupus, and T-cell lymphomas. Human PNP is therefore a target for inhibitor development aiming at T-cell immune response modulation. In addition, bacterial PNP has been used as reactant in a fast and sensitive spectrophotometric method that allows both quantitation of inorganic phosphate (Pi) and continuous assay of reactions that generate P i such as those catalyzed by ATPases and GTPases. Human PNP may therefore be an important biotechnological tool for P i detection. However, low expression of human PNP in bacterial hosts, protein purification protocols involving many steps, and low protein yields represent technical obstacles to be overcome if human PNP is to be used in either high-throughput drug screening or as a reagent in an affordable P i detection method. Here, we describe PCR amplification of human PNP from a liver cDNA library, cloning, expression in Escherichia coli host, purification, and activity measurement of homogeneous enzyme. Human PNP represented approximately 42% of total soluble cell proteins with no induction being necessary to express the target protein. Enzyme activity measurements demonstrated a 707-fold increase in specific activity of cloned human PNP as compared to control. Purification of cloned human PNP was achieved by a two-step purification protocol, yielding 48 mg homogeneous enzyme from 1 L cell culture, with a specific activity value of 80 U mg -1. © 2002 Elsevier Science (USA). All rights reserved.

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Four perylene derivatives (PTCD) have been used as transducing materials in taste sensors fabricated with nanostructured Langmuir-Blodgett (LB) films deposited onto interdigitated gold electrodes. The Langmuir monolayers of PTCDs display considerable collapse pressures, with areas per molecule indicative of an edge-on or head-on arrangement for the molecules at the air/water interface. The sensing units for the electronic tongue were produced from 5-layer LB films of the four PTCDs, whose electrical response was characterized with impedance spectroscopy. The distinct responses of the PTCDs, attributed to differences in their molecular structures, allowed one to obtain a finger printing system that was able to distinguish tastes (salty, sweet, bitter and sour) at 1 μM concentrations, which, in some cases, are three orders of magnitude below the human threshold. Using Principal Component Analysis (PCA) data analysis, the electronic tongue also detected trace amounts of a pesticide and could distinguish among samples of ultrapure, distilled and tap water, and two brands of mineral water. © 2004 by American Scientific Publishers. All rights reserved.

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Papoti, M., L.E.B. Martins, S.A. Cunha, A.M. Zagatto, and C.A. Gobatto. Effects of taper on swimming force and swimmer performance after an experimental ten-week training program. J. Strength Cond. Res. 21(2):538-542. 2007.- The purpose of this research was to examine how an 11-day taper after an 8.5-week experimental training cycle affected lactate levels during maximal exercise, mean force, and performance in training swimmers, independent of shaving, psychological changes, and postcompetition effects. Fourteen competition swimmers with shaved legs and torsos were recruited from the São Paulo Aquatic Federation. The training cycle consisted of a basic training period (endurance and quality phases) of 8.5 weeks, with 5,800 m·d -1 mean training volume and 6 d·wk -1 frequency; and a taper period (TP) of 1.5 weeks' duration that incorporated a 48% reduction in weekly volume without altering intensity. Attained swimming force (SF) and maximal performance over 200m maximal swim (Pmax) before and after taper were measured. After taper, SF and Pmax improved 3.6 and 1.6%, respectively (p < 0.05). There were positive correlations (p < 0.05) between SF and Pmax before (r = 0.86) and after (r = 0.83) the taper phase. Peak lactate concentrations after SF were unaltered before (6.79 ± 1.2 mM) and after (7.15 ± 1.8 mM) TP. Results showed that TP improved mean swimming velocity, but not in the same proportion as force after taper, suggesting that there are other factors influencing performance in faster swimming. © 2007 National Strength & Conditioning Association.

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During eight weeks, in summer, four endurance trained high performance horses were worked in resistence exercise, recieving two different types of hydratatio, water or an isotonic solution containing carbohydrates, with the objective to compare their performance physiological parameters. Only the RT (rectal temperature), HR (heart rate), RR (respiratory rate), weight, total protein, glucose, the electrolytes K, Ca and the muscular enzyme CK presented distance effect. The others parameters evaluated, there weren't any identified effects of treatment and of the interaction between distance and treatments, with a significancy level of 5%, and it was concluded that the isotonic solution containing carbohydrate didn't have any significant influence on the animal's performance when compared to water.

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Background. The aim of this study was to evaluate the influence of zero-value subtraction on the performance of two laser fluorescence (LF) devices developed to detect occlusal caries. Methods. The authors selected 119 permanent molars. Two examiners assessed three areas (cuspal, middle and cervical) of both mesial and distal portions of the buccal surface and one occlusal site using an LF device and an LF pen. For each tooth, the authors subtracted the value measured in the cuspal, middle and cervical areas in the buccal surface from the value measured in the respective occlusal site. Results. The authors observed differences among the readings for both devices in the cuspal, middle and cervical areas in the buccal surface as well as differences for both devices with and without the zero-value subtraction in the occlusal surface. When the authors did not perform the zero-value subtraction, they found statistically significant differences for sensitivity and accuracy for the LF device. When this was done with the LF pen, specificity increased and sensitivity decreased significantly. Conclusions. For the LF device, the zero-value subtraction decreased the sensitivity. For this reason, the authors concluded that clinicians can obtain measures with the LF device effectively without using zero-value subtraction. For the LF pen, however, the absence of the zero-value subtraction changed both the sensitivity and specificity, and so the authors concluded that clinicians should not eliminate this step from the procedure. Clinical Implications. When using the LF device, clinicians might not need to perform the zero-value subtraction; however, for the LF pen, clinicians should do so.