255 research outputs found

    Physical and Psychological Factors Affecting sportsman Performance: The moderating role of sports training: A case on Saudi Arabia Athletics

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    Using a questionnaire-based technique and Partial Least Squares Structural Equation Modeling, this study examined the moderating effect of sports training on the relationship between physical characteristics, psychological factors, and athletic performance among Saudi Arabian athletes (PLS-SEM). Using a straightforward sampling technique, the study recruited 250 male and female athletes from various Saudi Arabian sports groups and organizations. The study outcomes indicated that sports training significantly moderated the relationship between physical attributes and athletic performance among Saudi Arabian athletes. The data also revealed that sports training mediated the association between psychological factors and athletic performance, indicating that regular sports training can augment the positive effect of psychological factors on athletic performance. This study contributes to the literature on the moderating influence of sports training on the association between physical and psychological characteristics and athletic performance among Saudi Arabian athletes. The findings indicate frequent sports training can boost physical fitness and mental resiliency, enhancing athletic performance. The study emphasizes the relevance of adding sports training to athlete development programs in Saudi Arabia. More studies are advised to investigate other variables that may influence the association between physical and psychological components and athletic performance in Saudi Arabian athletes

    A Study of Fracture in a Rotating Disc

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    This investigation deals with the fracture produced in a disc by simple rotation cycles as well as rotation cycles under an imposed hydrostatic pressure. In both the cases, relations are obtained between the critical angular speed omega and the number of cycles N, required to cause fracture

    A Note on waves Generated at a Liquid Solid Interface-II (Viscous Effects)

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    This paper, being a continuation of a previous note of the same title, deals with the effect of viscosity on the interface waves propagated in a liquid layer overlying a generalized thermoelastic solid halfspace. This note extends the results of Harinath and has applications to defence science and geophysical problems. The problem considered has more relevance to the physical situations encountered in reality than its elastic counterpart. In other words, generalized thermoelasticity fits into the realistic situation better than classical elasticity or coupled thermoelasticity. The details pertaining to the non viscous effects of liquid layer overlying a perfectly elastic halfspace may be found in the treatise by Ewing, Jardetzky and Press those of coupled thermoelasticity in the treatise by Nowacki and details of wave propagation problems in generalized thermoelasticity in the concise paper by Harinath. The stress strain relations used for a viscous fluid may be found in Pipkin, with slight modifications, without any loss in generality. Most of the results obtained here are new

    Shc is required for ErbB2-induced inhibition of apoptosis but is dispensable for cell proliferation and disruption of cell polarity

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    Amplification and overexpression of ErbB2 strongly correlates with aggressive breast cancers. A deeper understanding of pathways downstream of ErbB2 signaling that are required for the transformation of human mammary epithelial cells will identify novel strategies for therapeutic intervention in breast cancer. Using an inducible activation of ErbB2 autophosphorylation qsite mutants and the MCF-10A three-dimensional (3D) culture system, we investigated pathways used by ErbB2 to transform the epithelia. We report that ErbB2 induces cell proliferation and loss of 3D organization by redundant mechanisms, whereas it disrupts apical basal polarity and inhibits apoptosis using Tyr 1201 and Tyr 1226/7, respectively. Signals downstream of Tyr 1226/7 were also sufficient to confer paclitaxel resistance. The Tyr 1226/7 binds Shc, and the knockdown of Shc blocks the ability of ErbB2 to inhibit apoptosis and mediate paclitaxel resistance. Tyr 1226/7 is known to activate the Ras/Erk pathway; however, paclitaxel resistance did not correlate with the activation of Erk or Akt, suggesting the presence of a novel mechanism. Thus, our results show that targeting pathways used by ErbB2 to inhibit cell death is a better option than targeting cell proliferation pathways. Furthermore, we identify a novel function for Shc as a regulator of apoptosis and drug resistance in human mammary epithelial cells transformed by ErbB2. Oncogene (2010) 29, 174-187; doi:10.1038/onc.2009.312; published online 12 October 200

    Optimal Drug Regimen and Combined Drug Therapy and its Efficacy in the Treatment of COVID-19 : An Within-Host Modeling Study

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    The COVID-19 pandemic has resulted in more than 30.35 million infections and 9, 50, 625 deaths in 212 countries over the last few months. Different drug intervention acting at multiple stages of pathogenesis of COVID-19 can substantially reduce the infection induced mortality. The current within-host mathematical modeling studies deals with the optimal drug regimen and the efficacy of combined therapy in treatment of COVID-19. The drugs/interventions considered include Arbidol, Remdesivir, Inteferon (INF) and Lopinavir/Ritonavir. It is concluded that these drug interventions when administered individually or in combination reduce the infected cells and viral load. Four scenarios involving administration of single drug intervention, two drug interventions, three drug interventions and all the four have been discussed. In all these scenarios the optimal drug regimen is proposed based on two methods. In the first method these medical interventions are modeled as control interventions and a corresponding objective function and optimal control problem is formulated. In this setting the optimal drug regimen is proposed. Later using the the comparative effectiveness method the optimal drug regimen is proposed based on basic reproduction number and viral load. The average infected cell count and viral load decreased the most when all the four interventions were applied together. On the other hand the average susceptible cell count decreased the best when Arbidol alone was administered. The basic reproduction number and viral count decreased the best when all the four interventions were applied together reinstating the fact obtained earlier in the optimal control setting. These findings may help physicians with decision making in treatment of life-threatening COVID-19 pneumonia.Comment: 16 pages, 13 figure

    3D culture reveals a signaling network

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    The behavior of a cell is significantly influenced by its context. Epithelial cells derived from glandular organs such as the breast recreate their glandular organization when grown under 3D culture conditions. While traditional monolayer cultures are powerful tools to understand how cells proliferate, grow and respond to stress, they do not recreate the 3D property observed in vivo. Multiple studies demonstrate that 3D organization can reveal novel and unexpected insights into the mechanisms by which normal and tumorderived epithelial cells function. In the present article we comment on a study that reports identification of a RasV12-induced IL-6 signaling network in mammary epithelial cells in 3D cultures

    Promoting integrated care in prostate cancer through online prostate cancer-specific holistic needs assessment: a feasibility study in primary care

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    PURPOSE: This study assessed the feasibility of implementing a novel model of integrated prostate cancer care involving an online prostate cancer-specific holistic needs assessment (sHNA) and shared digital communication between patients and their healthcare professionals (HCPs). The sHNA produces a semi-automated care plan that is finalised in consultation between the patient and their practice nurse. METHODS: Men living with and beyond prostate cancer were invited to participate in a 9-month non-randomised cluster controlled feasibility study. The intervention group was asked to complete the sHNA on three occasions. Data were collected using Patient Reported Outcome Measures (PROMs) at baseline, 10 and 24 weeks, and 9 months. Outcomes included recruitment, retention, acceptability, and engagement with the sHNA and PROMs. RESULTS: Fourteen general practices (8 intervention and 6 control), and 41 men (29 intervention and 12 control) participated. Initial patient engagement with the sHNA was high, with all but one receiving practice nurse-led follow-up and an individualised care plan. The sHNA proved useful in identifying ‘red flag’ symptoms, and helping practice nurses decide when to seek further medical care for the patients. There was a high level of acceptability for patients and HCPs. However, integration of care did not occur as intended because of problems linking hospital and general practice IT systems. CONCLUSION: While the study demonstrated the feasibility of implementing the sHNA, it did not meet the a priori progression criteria; as such, undertaking a definitive randomised controlled trial is not appropriate until the identified methodological and technical issues have been addressed

    Chaotic memristor

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    We suggest and experimentally demonstrate a chaotic memory resistor (memristor). The core of our approach is to use a resistive system whose equations of motion for its internal state variables are similar to those describing a particle in a multi-well potential. Using a memristor emulator, the chaotic memristor is realized and its chaotic properties are measured. A Poincar\'{e} plot showing chaos is presented for a simple nonautonomous circuit involving only a voltage source directly connected in series to a memristor and a standard resistor. We also explore theoretically some details of this system, plotting the attractor and calculating Lyapunov exponents. The multi-well potential used resembles that of many nanoscale memristive devices, suggesting the possibility of chaotic dynamics in other existing memristive systems.Comment: Applied Physics A (in press

    Thermochemistry, Morphology, and Optical Characterization of Germanium Allotropes

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    A thermochemical study of three germanium allotropes by differential scanning calorimetry (DSC) and oxidative high-temperature drop solution calorimetry with sodium molybdate as the solvent is described. Two allotropes, microcrystalline allo-Ge (m-allo-Ge) and 4H-Ge, have been prepared by topotactic deintercalation of Li_7Ge_(12) with methanol (m-allo-Ge) and subsequent annealing at 250 °C (4H-Ge). Transition enthalpies determined by differential scanning calorimetry amount to 4.96(5) ± 0.59 kJ/mol (m-allo-Ge) and 1.46 ± 0.55 kJ/mol (4H-Ge). From high-temperature drop solution calorimetry, they are energetically less stable by 2.71 ± 2.79 kJ/mol (m-allo-Ge) and 5.76 ± 5.12 kJ/mol (4H-Ge) than α-Ge, which is the stable form of germanium under ambient conditions. These data are in agreement with DSC, as well as with the previous quantum chemical calculations. The morphology of the m-allo-Ge and 4H-Ge crystallites was investigated by a combination of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Even though the crystal structures of m-allo-Ge and 4H-Ge cannot be considered as truly layered, these phases retain the crystalline morphology of the layered precursor Li_7Ge_(12). Investigation by diffuse reflectance infrared Fourier transform spectroscopy and UV–vis diffuse reflectance measurements reveal band gaps in agreement with quantum chemical calculations
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