392 research outputs found

    EFFECTS OF APPROACH VELOCITY TO THE CONTRIBUTION OF EACH BODY SEGMENTS TO THE TAKE-OFF MOVEMENT IN THE LONG JUMP

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    INTRODUCTION Much study suggested that approach velocity gave significant effects to the long jump performance However, there are very few studies effects of approach velocity to the role or the contribution of each body segments to the take-off movement in the long Jump, which is the purpose of this study Nine male long jumpers performed the long jump of the three types, Slow jump (S 10----15m-approachrun), Medium jump (M 25----30m-approachrun), Fast jump (F full approach of their own). Their take-off motions were filmed at 200Hz with Nac high speed camera. Two dimensional coordinates were obtained by digitizing the motions with a sampling frequency of 200Hz. The data was filtered with a Butterworth digital filter(Winter 1979) at 10Hz BSP of Chandler et al. (1975) were used to estimate the segmental centers of gravity and mass center of the whole body This data used to calculate the generated momenta and impulses (horizontal, vertical) of the arms (A), trunk (T: head and trunk), free leg (F) and take-off leg (TL), using the method of Ae and Shibukawa (1980). The mean percent contribution of the segments were obtained by dividing total impulse of each segment over the take-off phase by the whole body impulse RESULTS With the regard to the horizontal direction, the body segments contribution suggested the same proportion pattern all of the three types jumps. The highest (positive) contribution was made by the trunk (S: 4155±22.5%, M36.42± 18.23%, F54.85 ± 3024%) The contribution of the arms (S -5.97±281%, M:-6.34±5.21%, F:-9.54± 6.20%), The free leg (S: -5.85±481%, M: -1603±1120%, F: -722±3.10%) and take-off leg (S:-129.73±35.59%, M -11405±48.47%, F:-138.10±6550%) were negative. Most negative contribution was made by the take-off leg As for the vertical direction, the all body segments contribution of the three types jumps showed positive contribution (S; A 4.29±262%, T 4.06±423%, FL 0.69± 2.44%, TL 90 96±7.82%, M; A 600± 1.60%, T 9.54±9.37%, FL 010±210%, TL 84.36±11.14%, F; A 10.5±3.12%, T 8.02±604%, FL: 2.88±1.01%, TL 78.60 ± 14.56%). The take-off leg showed the highest percentage contribution As the approach velocity increased, so did the contribution of the arms, while the contribution of the take-off leg decreased. CONCLUSION With regard to the horizontal direction, the body segments contribution showed the same proportion pattern in all of the three types jumps The trunk made positive contribution to horizontal velocity, the trunk made positive contribution to horizontal velocity, the other body segments made negative contribution to horizontal velocity in horizontal direction. On the other hand, as the approach velocity increased, so did the contribution of the arms, while the contribution of the take-off leg decreased. The arms and take-off leg have a mutually supportive relationship in vertical direction

    Furthering the understanding of silicate-substitution in α-tricalcium phosphate : an X-ray diffraction, X-ray fluorescence and solid-state nuclear magnetic resonance study

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    High-purity (SupT) and reagent-grade (ST), stoichiometric and silicate-containing α-tricalcium phosphate (α-TCP: ST0/SupT0 and Si-TCP x = 0.10: ST10/SupT10) were prepared by solid-state reaction based on the substitution mechanism Ca3(PO4)(2-x)(SiO4)x. Samples were determined to be phase pure by X-ray diffraction (XRD), and Rietveld analysis performed on the XRD data confirmed inclusion of Si in the α-TCP structure as determined by increases in unit cell parameters; particularly marked increases in the b-axis and β-angle were observed. X-ray fluorescence (XRF) confirmed the presence of expected levels of Si in Si-TCP compositions as well as significant levels of impurities (Mg, Al and Fe) present in all ST samples; SupT samples showed both expected levels of Si and a high degree of purity. Phosphorus (31P) magic-angle-spinning solid-state nuclear magnetic resonance (MAS NMR) measurements revealed that the high-purity reagents used in the synthesis of SupT0 can resolve the 12 expected peaks in the 31P spectrum of α-TCP compared to the low-purity ST0 that showed significant spectral line broadening; line broadening was also observed with the inclusion of Si which is indicative of induced structural disorder. Silicon (29Si) MAS NMR was also performed on both Si-TCP samples which revealed Q0 species of Si with additional Si Q1/Q2 species that may indicate a potential charge-balancing mechanism involving the inclusion of disilicate groups; additional Q4 Si species were also observed, but only for ST10. Heating and cooling rates were briefly investigated by 31P MAS NMR which showed no significant line broadening other than that associated with the emergence of β-TCP which was only realised with the reagent-grade sample ST0. This study provides an insight into the structural effects of Si-substitution in α-TCP and could provide a basis for understanding how substitution affects the physicochemical properties of the material

    Mudanças nos compostos bioativos e atividade antioxidante de pimentas da região amazônica.

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    A Embrapa Amazônia Oriental possui um Banco Ativo de Pimenteira com diferentes genótipos do gênero Capsicum, os quais ainda não foram analisados, quanto às suas características funcionais e capacidade antioxidante. Este estudo objetivou determinar os teores de ácido ascórbico, compostos fenólicos, carotenoides totais e a atividade antioxidante total, em frutos imaturos e maduros de genótipos de pimentas Capsicum spp. As concentrações de vitamina C (100,76-361,65 mg 100 g-1 nos frutos imaturos e 36,70-157,76 mg 100 g-1 nos maduros) decresceram com a maturação dos frutos. Carotenoides totais não foram detectados nos frutos imaturos, porém, nos frutos maduros, observaram-se valores de 73,80-1349,97 mg g-1, em função do genótipo. Os teores de compostos fenólicos aumentaram nos frutos maduros (147,40-718,64 mg GAE 100 g-1), para oito dos nove genótipos avaliados. Os frutos de pimenteira apresentaram significativa atividade antioxidante (55,02-92,03 mM trolox g-1 nos frutos imaturos e 39,60-113,08 mM trolox g- 1 nos maduros). Concluiu-se que o grau de maturação dos frutos influenciou nos teores de compostos bioativos dos genótipos estudados. Destacaram-se, como genótipos promissores com potencial para serem utilizados em programas de melhoramento genético, IAN-186301 e IAN-186324, pelos altos teores de carotenoides totais; IAN-186301, IAN-186311, IAN-186312 e IAN-186313, com relação às altas concentrações de ácido ascórbico; IAN-186304 e IAN-186311, pelos altos teores de compostos fenólicos; e IAN-186311, para atividade antioxidante

    Mitochondrial complex I and cell death: a semi-automatic shotgun model

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    Mitochondrial dysfunction often leads to cell death and disease. We can now draw correlations between the dysfunction of one of the most important mitochondrial enzymes, NADH:ubiquinone reductase or complex I, and its structural organization thanks to the recent advances in the X-ray structure of its bacterial homologs. The new structural information on bacterial complex I provide essential clues to finally understand how complex I may work. However, the same information remains difficult to interpret for many scientists working on mitochondrial complex I from different angles, especially in the field of cell death. Here, we present a novel way of interpreting the bacterial structural information in accessible terms. On the basis of the analogy to semi-automatic shotguns, we propose a novel functional model that incorporates recent structural information with previous evidence derived from studies on mitochondrial diseases, as well as functional bioenergetics

    Anthracyclines, proteasome activity and multi-drug-resistance

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    BACKGROUND: P-glycoprotein is responsible for the ATP-dependent export of certain structurally unrelated compounds including many chemotherapeutic drugs. Amplification of P-glycoprotein activity can result in multi-drug resistance and is a common cause of chemotherapy treatment failure. Therefore, there is an ongoing search for inhibitors of P-glycoprotein. Observations that cyclosporin A, and certain other substances, inhibit both the proteasome and P-glycoprotein led us to investigate whether anthracyclines, well known substrates of P-gp, also inhibit the function of the proteasome. METHODS: Proteasome function was measured in cell lysates from ECV304 cells incubated with different doses of verapamil, doxorubicin, daunorubicin, idarubicin, epirubicin, topotecan, mitomycin C, and gemcitabine using a fluorogenic peptide assay. Proteasome function in living cells was monitored using ECV304 cells stably transfected with the gene for an ubiquitin/green fluorescent protein fusion protein. The ability of the proteasome inhibitor MG-132 to affect P-glycoprotein function was monitored by fluorescence due to accumulation of daunorubicin in P-glycoprotein overexpressing KB 8-5 cells. RESULTS: Verapamil, daunorubicin, doxorubicin, idarubicin, and epirubicin inhibited 26S chymotrypsin-like function in ECV304 extracts in a dose-dependent fashion. With the exception of daunorubicin, 20S proteasome function was also suppressed. The proteasome inhibitor MG-132 caused a dose-dependent accumulation of daunorubicin in KB 8-5 cells that overexpress P-glycoprotein, suggesting that it blocked P-glycoprotein function. CONCLUSION: Our data indicate that anthracyclines inhibit the 26S proteasome as well as P-glycoprotein. Use of inhibitors of either pathway in cancer therapy should take this into consideration and perhaps use it to advantage, for example during chemosensitization by proteasome inhibitors

    Lipidomics: A Tool for Studies of Atherosclerosis

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    Lipids, abundant constituents of both the vascular plaque and lipoproteins, play a pivotal role in atherosclerosis. Mass spectrometry-based analysis of lipids, called lipidomics, presents a number of opportunities not only for understanding the cellular processes in health and disease but also in enabling personalized medicine. Lipidomics in its most advanced form is able to quantify hundreds of different molecular lipid species with various structural and functional roles. Unraveling this complexity will improve our understanding of diseases such as atherosclerosis at a level of detail not attainable with classical analytical methods. Improved patient selection, biomarkers for gauging treatment efficacy and safety, and translational models will be facilitated by the lipidomic deliverables. Importantly, lipid-based biomarkers and targets should lead the way as we progress toward more specialized therapeutics
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