477 research outputs found

    Utilization of Inertial Measurement Units for Determining the Sequential Chain of Baseball Strike Posture

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    The purpose of this study was to employ inertial measurement units (IMU) with an eyetracking device to investigate different swing strategies between two levels of batters. The participants were 20 healthy males aged 20 to 30 years old, with ten professional and ten amateur batters. Eye gaze position, head, shoulder, trunk, and pelvis angular velocity, and ground reaction forces were recorded. The results showed that professional batters rotated segments more rhythmically and efficiently than the amateur group. Firstly, the professional group spent less time in the preparation stages. Secondly, the maximum angular velocity timing of each segment of the professional group was centralized in the swing cycle. Thirdly, the amateur group had significantly earlier gaze timing of the maximum angular velocity than the professional group. Moreover, the maximum angular velocity timing of the gaze was the earliest parameter among the five segments, and significantly earlier (at least 16.32% of cycle time) than the maximum angular velocity of the head, shoulder, trunk, and pelvis within the amateur group. The visual-motor coordination strategies were different between the two groups, which could successfully be determined by wearable instruments of IMU

    Scaling Laws and Transient Times in 3He Induced Nuclear Fission

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    Fission excitation functions of compound nuclei in a mass region where shell effects are expected to be very strong are shown to scale exactly according to the transition state prediction once these shell effects are accounted for. The fact that no deviations from the transition state method have been observed within the experimentally investigated excitation energy regime allows one to assign an upper limit for the transient time of 10 zs.Comment: 7 pages, TeX type, psfig, submitted to Phys. Rev. C, also available at http://csa5.lbl.gov/moretto/ps/he3_paper.p

    Evidence of Vortices on the Insulating Side of the Superconductor-Insulator Transition

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    The magnetoresistance of ultrathin insulating films of Bi has been studied with magnetic fields applied parallel and perpendicular to the plane of the sample. Deep in the strongly localized regime, the magnetoresistance is negative and independent of field orientation. As film thicknesses increase, the magnetoresistance becomes positive, and a difference between values measured in perpendicular and parallel fields appears, which is a linear function of the magnetic field and is positive. This is not consistent with the quantum interference picture. We suggest that it is due to vortices present on the insulating side of the superconductor-insulator transition.Comment: 4 pages, 3 figure

    Mutations in the C-terminus of the X protein of hepatitis B virus regulate Wnt-5a expression in hepatoma Huh7 cells: cDNA microarray and proteomic analyses

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    Background: The hepatitis B virus x gene (HBx) is a promiscuous transactivator implicated in the development of hepatocellular carcinoma (HCC). The present study was designed to investigate the molecular events regulated by HBx. Methods: Genomic and proteomic expression profiling was performed in Huh7 HCC cells transfected with HBx mutants with a C-terminal deletion. The gene and protein expression of wingless-type murine-mammary-tumour virus (MMTV) integration site family, member 5A (Wnt-5a) was validated by analyses of reverse transcription–polymerase chain reaction (RT–PCR), real-time RT–PCR, western blot and immunohistochemistry. Results: Differentially expressed genes and proteins were found in the transfected Huh7 HCC cells; most of them were involved in transcriptional regulation, although others including oncogenes or tumor suppressor genes, and molecules involved in cell junctions, signal transduction pathways, metabolism or the immune response were also observed. The expression of the Wnt-5a gene was elevated >10-fold in Huh7 cells transfected with the HBx3′-30 amino acid deletion mutant. However, the expression was downregulated by the transfection with the HBx3′-40 amino acid deletion mutant. The changes in Wnt-5a expression were also observed in human HCC tissues, compared with corresponding non-cancerous liver tissues. A negative correlation was found between the expression of Wnt-5a and HBx COOH mutations in HCC tissues. Conclusions: HBx mutants may participate in the development and progression of HCC, at least in part through the Wnt-5a pathway

    Ectopic over-expression of tristetraprolin in human cancer cells promotes biogenesis of let-7 by down-regulation of Lin28

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    Tristetraprolin (TTP) is a AU-rich element (ARE) binding protein and exhibits suppressive effects on cell growth through down-regulation of ARE-containing oncogenes. The let-7 microRNA has emerged as a significant factor in tumor suppression. Both TTP and let-7 are often repressed in human cancers, thereby promoting oncogenesis by derepressing their target genes. In this work, an unexpected link between TTP and let-7 has been found in human cancer cells. TTP promotes an increase in expression of mature let-7, which leads to the inhibition of let-7 target gene CDC34 expression and suppresses cell growth. This event is associated with TTP-mediated inhibition of Lin28, which has emerged as a negative modulator of let-7. Lin28 mRNA contains ARE within its 3′-UTR and TTP enhances the decay of Lin28 mRNA through binding to its 3′-UTR. This suggests that the TTP-mediated down-regulation of Lin28 plays a key role in let-7 miRNA biogenesis in cancer cells

    An Observational Study of the Relationship Between Outcome and Platelet Reactivity in Chinese Patients Undergoing PCI Loading with 600 mg Clopidogrel

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    Objectives: We sought to determine whether high posttreatment platelet reactivity (HPPR) to a 600 mg loading dose of clopidogrel affects outcomes in Chinese patients with acute coronary syndrome (ACS) following percutaneous coronary intervention (PCI) and to investigate whether there is a relationship between the number of platelet reactivity units (PRUs) and the characteristics of the patients. Background: Although impaired platelet response to clopidogrel is a strong predictor of unfavorable outcome after PCI, the impact of HPPR to a 600 mg loading dose of clopidogrel in Chinese patients with ACS undergoing PCI is still unknown. Methods: We performed observational research on 134 unselected patients with ACS undergoing urgent or planned PCI with a 600 mg loading dose of clopidogrel. Platelet activation was expressed as the PRU value measured by the VerifyNow assay. Results: Among the 134 patients (mean age 60.62 years [standard deviation 9.13 years], 60.4% male), there were 46 patients with HPPR (34.3%) and 88 patients without HPPR (65.7%). At a mean follow-up of 6 months (standard deviation 1 month), the rates of cardiac death, unstable angina, and rehospitalization for target lesion revascularization were higher in the HPPR group (19.6% vs. 6.8%, P=0.029). Multivariate analysis identified hemoglobin level and sex as independent predictors of the PRU value ( y =456.355−1.736 x 1 −31.880 x 2 , P<0.05). On receiver operating characteristic curve analysis, PRU values could significantly discriminate between patients with and patients without cardiac death, unstable angina, and rehospitalization for target lesion revascularization (area under the curve 0.758, 95% confidence interval 0.62–0.85, P=0.001, P<0.05). Conclusion: In patients with ACS, HPPR to a 600 mg loading dose of clopidogrel is associated with worse outcomes after PCI. There is some relationship between the PRU value and the hemoglobin level and sex. PRU values can predict the prognosis
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