Effects of vitamin D supplementation on maximal strength and power in athletes: a systematic review and meta-analysis of randomized controlled trials.

Background: Vitamin D is thought to be a powerful modulator of skeletal muscle physiology. However, available data on the effects of vitamin D supplementation on muscle function in athletes are limited and with mixed results. This meta-analysis therefore, aimed to quantitatively summarize the up-to-date literature assessing the effects of vitamin D supplementation on muscle strength and power in athletes.

Low-Barrier Hydrogen Bonds in Negative Thermal Expansion Material H [Co(CN) ].

The covalent nature of the low-barrier N-H-N hydrogen bonds in the negative thermal expansion material H [Co(CN) ] has been established by using a combination of X-ray and neutron diffraction electron density analysis and theoretical calculations. This finding explains why negative thermal expansion can occur in a material not commonly considered to be built from rigid linkers. The pertinent hydrogen atom is located symmetrically between two nitrogen atoms in a double-well potential with hydrogen above the barrier for proton transfer, thus forming a low-barrier hydrogen bond.

Chemical bonding origin of the unexpected isotropic physical properties in thermoelectric MgSb and related materials.

The MgSb structure is currently being intensely scrutinized due to its outstanding thermoelectric properties. Usually, it is described as a layered Zintl phase with a clear distinction between covalent [MgSb] layers and ionic Mg layers. Based on the quantitative chemical bonding analysis, we unravel instead that MgSb exhibits a nearly isotropic three-dimensional bonding network with the interlayer and intralayer bonds being mostly ionic and surprisingly similar, which results in the nearly isotropic structural and thermal properties.

Echocardiographic variables in healthy North American Salukis.

Introduction: To report normal echocardiographic variables from a population of healthy Salukis in North America.

Animals: The study included 83 healthy adult Salukis from North America with structurally normal hearts.

Methods: All animals underwent a full physical examination and two-dimensional, M-mode, and Doppler echocardiography using the right parasternal and left apical views with the left ventricular volumes calculated using the Simpson's method of discs.