199 research outputs found

    Ground Reaction Forces of Dart-Throwing at Different Target Heights

    Get PDF
    The purpose of the study was to explore whether dart players produce different lower limb control strategies when throwing darts at spatially separated targets in the vertical direction. Eight experienced darts players (height 1.75±0.04 m, mass 83.4±19.3 kg) participated in this research. Two Multi-Axis Force Plates were used to collect GRF data on both legs and synchronized with a Motion Capture System. The participants threw darts at three targets at different heights, which were the upper section of the 20 point area, bullseye and lower section of the 3 point area. The results showed that the amplitude of anterior-posterior GRF of their front legs were significantly different when darts was thrown at the 20 zone, bullseye and 3 zone respectively. Our study found that the braking forces of the front legs were greater when a dart was being thrown at the highest target (20 points) than when it was being thrown at the lowest target (3 points)

    LOWER LIMB STABILIZATION STRATEGIES OF DART ATHLETES AT DIFFERENT LEVELS

    Get PDF
    The purpose of the study was to understand lower limb stabilization strategies during the acceleration phase of dart throwing in athletes at different levels. Multi-Axis Force Plates and 3D Motion Capture were adopted to collect data. Six male darts athletes, including three elite athletes and three sub elite athletes, throw darts to hit Bull\u27s Eye abiding the rules of the World Darts Federation. The study shows that during acceleration phase, the ground reaction force of elite athletes changes substantially, while the change of ground reaction force of sub elite athletes was relatively small. Significant difference of the change in the front foot ground reaction force (GRF) on a vertical axis is reached (p\u3c0.05). The cause may be because the elite players use greater GRF transition from rear foot and front foot than sub elite players. On the contrast, sub elite athletes are still in the stage of integration, thus lower limb movement is minimized in order to stabilize the throw

    Dynamical Decoupling of Qubits in Spin Bath under Periodic Quantum Control

    Full text link
    We investigate the feasibility for the preservation of coherence and entanglement of one and two spin qubits coupled to an interacting quantum spin-1/2 chain within the dynamical decoupling (DD) scheme. The performance is examined by counting number of computing pulses that can be applied periodically with period of TT before qubits become decoherent, while identical decoupling pulse sequence is applied within each cycle. By considering pulses with mixed directions and finite width controlled by magnetic fields, it is shown that pulse-width accumulation degrades the performance of sequences with larger number of pulses and feasible magnetic fields in practice restrict the consideration to sequences with number of decoupling pulses being less than 10 within each cycle. Furthermore, within each cycle TT, exact nontrivial pulse sequences are found for the first time to suppress the qubit-bath coupling to O(TN+1)O(T^{N+1}) progressively with minimum number of pulses being 4,7,124,7,12 for N=1,2,3N=1,2,3. These sequences, when applied to all qubits, are shown to preserve both the entanglement and coherence. Based on time-dependent density matrix renormalization, our numerical results show that for modest magnetic fields (10-40 Tesla) available in laboratories, the overall performance is optimized when number of pulses in each cycle is 4 or 7 with pulse directions be alternating between x and z. Our results provide useful guides for the preservation of coherence and entanglement of spin qubits in solid state.Comment: 11 pages, 9 figure

    The incidence of symptomatic venous thromboembolism following hip fractures with or without surgery in Taiwan

    Get PDF
    AbstractBackgroundInformation on the incidence of venous thromboembolism (VTE) following hip fractures in Asia is rare. This study will investigate the epidemiology of symptomatic VTE in Taiwanese patients experiencing hip fractures.Methods and resultsWe used Taiwan's National Health Insurance Research Database to retrospectively identify patients (≧45years) who experienced hip fractures from 1998 to 2007 and were followed up for 3months after the discharge. Logistic regression analysis determined the independent risk factors of symptomatic VTE after the fractures. We identified 134,034 patients (mean age: 76.2±9.7years; female: 57.8%) who experienced hip fractures, 83.2% of whom underwent hip surgery. The overall pharmacological thromboprophylaxis rate was 2.7%. The mean length of stay was 11.3±7.9days. The 3-month cumulative incidence of symptomatic VTE was 77 events per 10,000 persons. Multivariate analysis showed that previous DVT, previous PE, varicose veins, cancer, heart failure, renal insufficiency, and older age were independent risk factors of developing VTE.ConclusionsThe incidence of symptomatic VTE after hip fractures is low in Taiwan. Patients rarely received pharmacological thromboprophylaxis following hip fractures. Universal thromboprophylaxis for patients experiencing hip fractures was not necessary in Taiwan, but it should be considered in high-risk populations

    Reduced expression of alpha-1,2-mannosidase I extends lifespan in Drosophila melanogaster and Caenorhabditis elegans

    Get PDF
    Exposure to sub-lethal levels of stress, or hormesis, was a means to induce longevity. By screening for mutations that enhance resistance to multiple stresses, we identified multiple alleles of alpha-1,2-mannosidase I (mas1) which, in addition to promoting stress resistance, also extended longevity. Longevity enhancement is also observed when mas1 expression is reduced via RNA interference in both Drosophila melanogaster and Caenorhabditis elegans. The screen also identified Edem1 (Edm1), a gene downstream of mas1, as a modulator of lifespan. As double mutants for both mas1 and Edm1 showed no additional longevity enhancement, it appeared that both mutations function within a common pathway to extend lifespan. Molecular analysis of these mutants revealed that the expression of BiP, a putative biomarker of dietary restriction (DR), is down-regulated in response to reductions in mas1 expression. These findings suggested that mutations in mas1 may extend longevity by modulating DR

    Myocardium-derived conditioned medium improves left ventricular function in rodent acute myocardial infarction

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>We investigated whether myocardium-derived conditioned medium (MDCM) is effective in preserving left ventricular (LV) function in a rat acute myocardial infarction (AMI) model.</p> <p>Methods</p> <p>Adult male Sprague-Dawley (SD) rats (n = 36) randomized to receive either left coronary artery ligation (AMI induction) or thoracotomy only (sham procedure) were grouped as follows (n = 6 per group): Group I, II, and III were sham-controls treated by fresh medium, normal rat MDCM, and infarct-related MDCM, respectively. Group IV, V, and VI were AMI rats treated by fresh medium, normal MDCM, and infarct-related MDCM, respectively. Either 75 μL MDCM or fresh medium was administered into infarct myocardium, followed by intravenous injection (3 mL) at postoperative 1, 12, and 24 h.</p> <p>Results</p> <p>In vitro studies showed higher phosphorylated MMP-2 and MMP-9, but lower α-smooth muscle actin and collagen expressions in neonatal cardiac fibroblasts treated with MDCM compared with those in the cardiac fibroblasts treated with fresh medium (all p < 0.05). Sirius-red staining showed larger collagen deposition area in LV myocardium in Group IV than in other groups (all p < 0.05). Stromal cell-derived factor-1α and CXCR4 protein expressions were higher in Group VI than in other groups (all p < 0.05). The number of von Willebrand factor- and BrdU-positive cells and small vessels in LV myocardium as well as 90-day LV ejection fraction were higher, whereas oxidative stress was lower in Group VI than in Group IV and Group V (all p < 0.05).</p> <p>Conclusion</p> <p>MDCM therapy reduced cardiac fibrosis and oxidative stress, enhanced angiogenesis, and preserved 90-day LV function in a rat AMI model.</p

    Narcissistic self-sorting of n-acene nano-ribbons yielding energy-transfer and electroluminescence at p-n junctions

    Get PDF
    The 2,3-didecyloxy derivative of an n-type anthracene (n-BG) and a p-type tetracene (p-R) have been synthesized and their self-assembly into nano-ribbons studied. Hyperspectral fluorescence imaging revealed their narcissistic self-sorting, leading to separated nanoribbons emitting with very different colors (blue or green for n-BG, depending on the growth solvent, and red for p-R). It is unique that the usual origins of self-sorting, such as specific H-bonding, different growth kinetics, or incompatible steric hindrance can be ruled out. Hence, the narcissistic behaviour is herein proposed to originate from a sofar unconsidered cause: the discrepancy between the quadrupolar character of n-BG and dipolar character of p-R. At the p-n junctions of these nanoribbons, inter-ribbon FRET and electro-luminescence switch-on were observed by fluorescence/luminescence microscopy.The authors acknowledge the financial support of the European Research Council Marie Curie Actions (FP7-PEOPLE-2012-ITN SMARTNET Grant agreement Nr 316656); the CNRS; the French Ministry of Education and Research; the Region Aquitaine; the ANR-06-JCJC-0030; the Department of Education, Science and Universities of the Basque Country Government (postdoctoral grant and project IT1639-22); the "Arina" informatic cluster of UPV/EHU; the facilities ELORGA of UB; and the ANR-17-CE24-0033-01 RESOLVE. The authors thank Dr A. Mendez-Ardoy for the CV measurements and CESAMO for structural analyses (ISM, Univ. Bordeaux)

    Intra-coronary administration of tacrolimus markedly attenuates infarct size and preserves heart function in porcine myocardial infarction

    Get PDF
    BACKGROUND: We test the hypothesis that intra-coronary tacrolimus administration can limit infarct size and preserve left ventricular ejection fraction (LVEF) after acute myocardial infarction (AMI) through ligating left anterior descending coronary artery (LAD) in mini-pigs. METHODS: Twelve male mini-pigs were randomized into AMI-saline (MI-only) group and AMI-tacrolimus (MI-Tac) group that received intra-coronary saline (3.0 mL) and tacrolimus (0.5 mg in 2.5 mL saline) injection, respectively, beyond site of ligation 30 minutes after LAD occlusion. RESULTS: Larger infarct area was noted in MI-only group (p < 0.001). Inflammatory biomarkers at protein [oxidative stress, tumor necrotic factor-α, nuclear factor-κB], gene (matrix metalloproteinase-9, plasminogen activator inhibitor-1), and cellular (CD40+, CD68+ inflammatory cells) levels were remarkably higher in MI-only animals (p < 0.01). Conversely, anti-inflammatory biomarkers at gene level (Interleukin-10), gene and protein level (endothelial nitric oxide synthase), and anti-oxidant biomarkers at both gene and protein levels [heme oxygenase 1, NAD(P)H:quinone oxidoreductase] were lower in MI-only group (p < 0.01). Number of apoptotic nuclei and apoptotic biomarkers expressions at gene and protein levels (Bax, caspase 3) were notably higher, whereas anti-apoptotic biomarkers at gene and protein levels (Bcl-2), LVEF, and fractional shortening were markedly lower in MI-only group (p < 0.001). CONCLUSION: Intra-coronary administration of tacrolimus significantly attenuated infarct size and preserved LV function
    corecore