2,439 research outputs found

    The Υ(1S)\Upsilon(1S) leptonic decay using the principle of maximum conformality

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    In the paper, we study the Υ(1S)\Upsilon(1S) leptonic decay width Γ(Υ(1S)+)\Gamma(\Upsilon(1S)\to \ell^+\ell^-) by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, ΓΥ(1S)e+e=1.2620.175+0.195\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175} keV, where the error is squared average of those from αs(MZ)=0.1181±0.0011\alpha_s(M_{Z})=0.1181\pm0.0011, mb=4.93±0.03m_b=4.93\pm0.03 GeV and the choices of factorization scales within ±10%\pm 10\% of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.Comment: 6 pages, 4 figure

    THE EFFECTS OF A 16-WEEK TAI CHI INTERVENTION PROGRAM ON NEUROMUSCULAR RESPONSES AND MUSCLE ACTIVITY OF THE LOWER EXTREMITY IN ELDERLYS

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    This study examined the effects of a 16-week Tai Chi (TC) training program on muscle strength and endurance of the knee and the ankle, as well as the neuromuscular response to perturbation among elderly people. Forty elderly individuals participated in and completed the study. They were randomly placed into either the TC intervention group (n=22) or the control group (n=18), after which pre- and post-intervention measurements were conducted. The maximum concentric strength and endurance of the knee and ankle were measured by an isokinetic dynamometer. The neuromuscular response indicated by the reaction time of the muscles in the lower limb was examined by measuring the onset latency of the muscles to perturbations on the ankle joint through an electromyography system. The results showed that the 16-week TC intervention the significantly increased knee flexor strength and improved the latency of semitendinous muscle

    DIFFERENCE OF HYDROSTATIC WEIGHTING AND SKINFOLD METHODS IN DETERMINATON OF BODY FAT IN CHINESE ADULTS

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    INTRODUCTION: Body fat content can be determined by Hydrostatic weighing method and skin fold measurement. The former is the most accurate and is thought as “golden Standard”, while the later is an easy and simple way. Measurement of body fat content using skin fold method is by calculation based on the measured skin fold. But the formulas used to calculate body fat content were developed based on the studies in foreigners. We hypothesized that there was significant difference in the body fat content of Chinese determined by hydrostatic weighing and skin fold methods in which the formula was from the studies in foreigners. The formula developed based on the study in foreigners might not be suitable in the determination of body fat content in Chinese

    Nonlinear Vibration of Ladle Crane due to a Moving Trolley

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    The structural vibration of the main beam of a crane causes fatigue damage and discomfort to the driver. The swing of the payload has an effect on positioning precision, especially for a ladle crane, and this directly affects production safety. To study the influence of system parameters on the vibration of a crane’s main beam and the angle of the payload, a system consisting of the main beam, trolley, payload, and cabin was constructed. A rigid-flexible coupling dynamic model of a moving trolley with a hanging payload that moves on the flexible main beam with a concentrated cabin mass is established, and the direct integration method is used to solve the nonlinear differential equations of system vibration, which are obtained through Lagrange’s equation. Then, the time domain responses of the flexible main beam, payload angle, and cabin vibration are obtained. The influences of the trolley running speed, quality of the payload, and quality and position of the cabin on the vibration of the main beam and payload angle are analyzed. The results indicate that the amplitude of the main beam is directly proportional to the quality of the trolley, payload, and cab; the position of the cabin is closer to the mid-span; the amplitude of the main beam is larger; the structural damping has some influence on the vibration of the main beam; and the swing angle of the payload is related to the maximum running speed of the trolley, acceleration time, and length of the wire rope. In order to reduce the vibration of the main beam and cabin, the connection stiffness of the cabin should be ensured during installation

    Model Population Analysis for Statistical Model Comparison

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    Molecular Target Therapy against Neuroblastoma

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    Neuroblastoma, originated from neural crest cells, is the most common extracranial solid tumor in childhood. Treatment is of limited utility for high-risk neuroblastoma and prognosis is poor. The high incidence of resistance of advanced-stage neuroblastoma to conventional therapies has prompt investigators to search for novel therapeutic approaches. Activation of IGF-R/PI3K/Akt/mTOR signaling pathway correlates with oncogenesis, poor prognosis, and chemotherapy resistance in neuroblastoma. Therefore, we investigated the effect of IGF-R/PI3K/Akt/mTOR signaling inhibitors in neuroblastoma. Significantly, IGF-R/PI3K/Akt/mTOR signaling inhibitors effectively inhibited cell growth and induced cell cycle arrest, autophagy, and apoptosis in neuroblastoma cells. Moreover, IGF-R/PI3K/Akt/mTOR signaling inhibitors significantly reduced tumor growth in mice xenograft model without apparent toxicity. Therefore, these results highlight the potential of IGF-R/PI3K/Akt/mTOR signaling pathway as a promising target for neuroblastoma treatment. Therefore, IGF-1R/PI3K/Akt/mTOR signaling inhibitors should be further investigated for treatment in clinical trials for high-risk neuroblastoma

    Neuroprotective effect of thiamine triethylorthoformate conjugate against Parkinson disease in a mouse model

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    Purpose: To investigate the effect of thiamine triethylorthoformate conjugate (TTO) on Parkinson disease (PD) in vitro and in vivo in a mice model. Methods: The effect of TTO on behavioural changes in PD mouse model was studied using pole, traction and swimming tests. Astrocyte proliferation after TTO treatment was assessed using 3 (4, 5 dimethyl 2 thi¬azolyl) 2, 5 diphenyl 2 H tetrazolium bromide (MTT) assay. Apoptosis was determined with flow cytometry using Annexin V Fluorescein isothiocyanate kit. Results: Treatment of PD mice with TTO led to a decrease in climbing time, increase in suspension score and enhancement of swimming score, when compared to the untreated group (p < 0.05). Treatment of astrocytes with TTO prior to MPP incubation significantly increased proliferation (p < 0.05). Apoptosis induction in astrocytes by MPP was attenuated by pre-treatment with TTO. Pre-treatment of astrocytes with 10 µM TTO markedly reduced JNK activation, when compared to astrocytes incubated with MPP alone (p < 0.05). Up-regulation of Bax and down-regulation of Bcl 2 by MPP in astrocytes were attenuated by pre-treatment with TTO. MPP-induced up-regulation of cleaved caspase 3 was suppressed in astrocytes by TTO pre-treatment (p < 0.05). Conclusion: Treatment with TTO prevents MPP+ -induced neuronal damage in vitro in astrocytes and in vivo in mice. The neuro-protective effect of TTO involves down-regulation of JNK activation, inhibition of caspase-3 level, decrease in Bax and increase in Bcl-2 expression. Thus, TTO has a potential for use in the treatment of Parkinson’s disease
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