2,729 research outputs found

    Cardiac structure and function in young endurance athletes and nonathletes

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    The purpose of this study was to examine, in male adolescents, the effects of long-term endurance training on cardiac structure and function, by adopting a cross-sectional comparison with a nonathletic control group. A total of 13 endurance-trained (EX) and seven untrained (CON) male adolescents (mean &plusmn; SE, age = 15.3 &plusmn; 0.3 and 15.2 &plusmn; 0.28 yrs, respectively) underwent echocardiography at rest to determine left ventricular enddiastolic dimension (LVDd), left ventricular end-systolic dimension (LVDs), left ventricular posterior wall thickness (LVPW), stroke volume (SV), and cardiac output (CO). On separate days, incremental exercise tests were conducted on a cycle ergometer to measure peak oxygen uptake (VO2max) and anaerobic power. VO2max was greater in the endurance group (54.4 &plusmn; 1.8 mL min&ndash;1 kg&ndash;1) than in the control group (45.8 &plusmn; 1.6 mL min&ndash;1 kg&ndash;1; p &lt; 0.05). Mean exercise time was longer in EX (12.9 &plusmn; 0.7 min) than CON (10.4 &plusmn; 0.8 min; p &lt; 0.05). No significant differences were noted between the two groups in resting heart rate, maximal heart rate, LVDd, LVDs, LVPW, SV, SV indexed, CO, and CO indexed, or in the anaerobic strength. These data provide evidence that endurance-trained adolescent males develop superior exercise performance before the cardiac remodeling that is evident in trained adult athletes.<br /

    Simulation and Analysis of Indoor Visible Light Propagation Characteristics Based on the Method of SBR/Image

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    The indoor visible light propagation characteristics are simulated and analyzed using the method of SBR/Image (shooting and bounding ray tracing/Image). A good agreement is achieved between the results simulated and the results given in published literature. So the correctness of the method has been validated. Some propagation parameters are obtained in the simulation, such as the indoor received power distribution, statistical distribution of phase angle of received power, RMS (root mean square) delay spread, direction of arrival, and Doppler shift. The foundation for the wireless network coverage of indoor visible light communication system is provided by the analysis of the above results

    SIMULATION AND ANALYSIS OF 60 GHz MILLIMETER- WAVE INDOOR PROPAGATION CHARACTERISTICS BASE ON THE METHOD OF SBR/IMAGE

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    Abstract-In this paper, 60 GHz millimeter-wave indoor propagation characteristics are simulated and analyzed using the method of SBR/IM (shooting and bounding ray tracing/image). And the simulated and measured results agree well, so the correctness of the method has been validated. Some propagation parameters are obtained in the simulation, such as the indoor reception power distribution, distribution of phase angle of received power, root mean square (RMS) delay spread, direction of arrival, RMS angular spread, Doppler shift, etc. The analysis of the above results provides the foundation for the indoor coverage of millimeter-wave communication system

    Functionalized MoS2 nanosheet-capped periodic mesoporous organosilicas as a multifunctional platform for synergistic targeted chemo-photothermal therapy

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    The combination of different therapies into a single platform has attracted increasing attention as a potential synergistic tumor treatment. Herein, the fabrication of a novel folate targeted system for chemo-photothermal therapy by using thioether-bridged periodic mesoporous organosilica nanoparticles (PMOs) as a drug-loading vehicle is described. The novel targeted molecular bovine serum albumin-folic acid-modified MoS2 sheets (MoS2-PEI-BSA-FA) were successfully synthesized and characterized, and then utilized as a capping agent to block PMOs to control the drug release and to investigate their potential in near-infrared photothermal therapy. The resulting PMOs–DOX@MoS2–PEI-BSA-FA complexes had a uniform diameter (196 nm); high DOX loading capacity (185 mg/g PMOs-SH); excellent photothermal transformation ability; and good biocompatibility in physiological conditions. The PMOs–DOX@MoS2–PEI-BSA-FA exhibited pH-dependence and near infrared (NIR) laser irradiation-triggered DOX release. In vitro experimental results confirmed that the material exhibits excellent photothermal transfer ability, outstanding tumor killing efficiency and specificity to target tumor cells via an FA-receptor-mediated endocytosis process. The in vivo experiments further demonstrated that the platform for synergistic chemo-photothermal therapy could significantly inhibit tumor growth, which is superior to any monotherapy. Meanwhile, cytotoxicity assays and histological assessments show that the engineered PMOs@MoS2–PEI-BSA-FA have good biocompatibility, further inspiring potential biomedical applications. Overall, this work describes an excellent drug delivery system for chemo-photothermal synergistic targeted therapy having good drug release properties, which have great potential in cancer therapy

    2,2-Dimethyl-5-[(pyridin-2-yl­amino)­methyl­idene]-1,3-dioxane-4,6-dione

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    In the title compound, C12H12N2O4, the dihedral angle between the pyridine and enamine planes is 3.5 (3)°, while the angle between the dioxanedione (seven atoms) and enamine planes is 4.6 (3)°. The dioxane ring approximates an envelope conformation
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