44 research outputs found

    The combination of exercise training and Zataria multiflora supplementation increase serum irisin levels in postmenopausal women

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    Background:We examined the effect of antioxidant supplementation and exercise on irisin within postmenopausal women.Methods:Forty-eight participants (age: 55.7 ± 4.9 years; weight: 68.0 ± 6.3 kg; BMI 27.0 ± 2.7; mean ± SD) were randomized into four groups for the eight week intervention: control group (CG; n = 12), resistance training group (RTG; n = 12), supplementation with Zataria multiflora group (ZG; n = 12), or supplementation with Z. multiflora and resistance training group (ZRTG; n = 12). RTG and ZRTG performed circuit resistance training, and both ZG and ZRTG consumed 500 mg of Z. multifloraevery day during the intervention. Blood samples were taken 48 hours before and after the intervention.Results:There was a significant difference in irisin at post-training, with greater levels in ZRTG compared to CG. A significant increase was noted for irisin at post-training compared to pre-training for ZG, RTG, and ZRTG. Moreover, we identified a significant decrease in malondialdehyde in the RTG and ZRTG groups and increase in glutathione in the ZG, RTG, and ZRTG groups when compared to CG.Conclusion:These findings showed that exercise, Z. multiflora supplementation or their combination led to an increase in irisin

    Knowledge translation in Iranian universities: Need for serious interventions

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    Background: The aim of this study was to assess the status of knowledge translation (KT) in Iranian medical science universities in order to assess the strengths and weaknesses of the most important organizations responsible for producing knowledge in the country.Methods: The KT activities were assessed qualitatively and quantitatively in nine universities using the Self-Assessment Tool for Research Institutes.Results: The strengths and weaknesses of universities were determined using seven main themes: priority setting; research quality and timeliness; researchers' KT capacities; interaction with research users; the facilities and prerequisites of KT; the processes and regulations supporting KT; and promoting and evaluating the use of evidence.The quantitative and qualitative results showed that the Iranian universities did not have an appropriate context for KT. There were significant shortcomings in supportive regulations, facilities for KT activities, and the level of interaction between the researchers and research users.Conclusions: The shortcomings in KT were mostly in the area of stewardship and policymaking (macro level), followed by planning and implementation at the universities. In order to strengthen KT in Iran, it should occupy a prominent and focused role in the strategies of the country's health research system. © 2013 Gholami et al.; licensee BioMed Central Ltd

    Improving the vibration suppression capabilities of a magneto-rheological damper using hybrid active and semi-active control

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    This paper presents a new hybrid active & semi-active control method for vibration suppression in flexible structures. The method uses a combination of a semi-active device and an active control actuator situated elsewhere in the structure to suppress vibrations. The key novelty is to use the hybrid controller to enable the magneto-rheological damper to achieve a performance as close to a fully active device as possible. This is achieved by ensuring that the active actuator can assist the magneto-rheological damper in the regions where energy is required. In addition, the hybrid active & semi-active controller is designed to minimize the switching of the semi-active controller. The control framework used is the immersion and invariance control technique in combination with sliding mode control. A two degree-of-freedom system with lightly damped resonances is used as an example system. Both numerical and experimental results are generated for this system, and then compared as part of a validation study. The experimental system uses hardware-in-the-loop to simulate the effect of both the degrees-of-freedom. The results show that the concept is viable both numerically and experimentally, and improved vibration suppression results can be obtained for the magneto-rheological damper that approach the performance of an active device

    Metabolic dysregulation in vitamin E and carnitine shuttle energy mechanisms associate with human frailty

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    Global ageing poses a substantial economic burden on health and social care costs. Enabling a greater proportion of older people to stay healthy for longer is key to the future sustainability of health, social and economic policy. Frailty and associated decrease in resilience plays a central role in poor health in later life. In this study, we present a population level assessment of the metabolic phenotype associated with frailty. Analysis of serum from 1191 older individuals (aged between 56 and 84 years old) and subsequent longitudinal validation (on 786 subjects) was carried out using liquid and gas chromatography-mass spectrometry metabolomics and stratified across a frailty index designed to quantitatively summarize vulnerability. Through multivariate regression and network modelling and mROC modeling we identified 12 significant metabolites (including three tocotrienols and six carnitines) that differentiate frail and non-frail phenotypes. Our study provides evidence that the dysregulation of carnitine shuttle and vitamin E pathways play a role in the risk of frailty

    Flutter of aircraft wings carrying a powered engine under roll maneuver

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    The flutter analysis of a swept aircraft wing-store configuration subjected to follower force and undergoing a roll maneuver is presented. Concentrated mass, follower force, and roll angular velocity terms are combined in the governing equations, which are obtained using the Hamilton's variational principle. The wing is modeled from a classical beam theory and incorporates bending-torsion flexibility. Heaviside and Dirac delta functions are used to consider the location and properties of the external mass and the follower force. Also, Peters's unsteady aerodynamic pressure loadings is considered and modified to take into account the effect of the wing sweep angle. The extended Galerkin's method is applied to convert the partial differential equations into a set of ordinary differential equations. Numerical simulations are validated with available published results. Simulation results are presented to show the effects on the wing flutter of the roll angular velocity, sweep angle, follower force, and store mass and its location. Results are indicative of the significant effect of the rigid-body roll angular velocity and the follower force on the wing-store dynamic stability. Furthermore, it is shown that the distances between the wing root and the aircraft center of gravity, acting location of the roll angular velocity, considerably affects the wing-engine flutter speed and frequenc

    Engine Placement Effects on the Flutter of a Medium-Range Box-Wing Aircraft

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    This study investigated the effects of powered engines on the stability boundaries of a box-wing configuration. The governing equations were obtained using Hamilton's principle. The equivalent effects of engine's mass and thrust were simulated using a concentrated mass which was subjected to a follower force. The structural dynamics of the box wing were modeled using two cantilever beams which were attached to each other through two longitudinal and torsional springs at their tips. The aerodynamic loads applied on the wings were calculated using Wagner's unsteady aerodynamic model. The time-dependent and the parameter-dependent integral parts were eliminated using the multistep semianalytical method. To validate the developed aeroelastic model, the flutter speed and frequency of conventional wings and box wings were obtained, and very good agreement was observed. The analysis showed that the stability of the wing can be affected when the effects of engines are considered. Furthermore, the engine placement and thrust effects on the box-wing flutter speed and frequency were considered

    Nonconservative Stability Analysis of Columns with Various Loads and Boundary Conditions

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    In this paper, the stability analysis of the elastic columns subjected to seven different types of the nonconservative force is investigated on the basis of fully intrinsic beam equations. The generalized differential quadrature method is used for the discretization of the first-order intrinsic equations and corresponding boundary conditions. Altogether, four important boundary conditions—simply supported, clamped-simply supported, clamped-free, and clamped-clamped conditions—are considered. Furthermore, the effect of the combined action of an end-concentrated force and a distributed tangential follower force is investigated. To confirm the validity of the proposed intrinsic formulations, the present results are compared with those obtained from classical formulations. Our results reveal that the fully intrinsic formulation is a suitable framework to model nonconservative problems
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