BackgroundConsumption of pre-workout dietary supplements by both recreational and competitive athletes has increased dramatically in recent years. The purpose of this study was to determine the acute effects of a caffeine-containing pre-workout dietary supplement on various measures of performance including anaerobic power, upper and lower body power, and upper body strength in recreationally trained males.MethodsThirteen males (mean ± SD age = 24 ± 6 yrs; height = 180.3 ± 5 cm; body mass = 83.4 ± 9 kg) participated in this investigation in which they reported to the laboratory on four separate occasions, each separated by one week. Each subject underwent an initial familiarization session on week one followed by baseline (BA) performance testing on week two. Performance testing included a medicine ball put (MBP) to determine upper body explosive power, vertical jump test (VJ) to determine lower body explosive power, one-rep maximum bench press (1-RM) for determining upper body strength, and a Wingate Anaerobic Power Test (WAnT) to determine measures of anaerobic power. On week three, subjects were randomly assigned to ingest either a pre-workout supplement (SUP) or a placebo (PL) and again complete the performance testing protocol. Subjects were provided with the crossover treatment on the fourth and final week. Performance testing commenced 20-minute following ingestion of both treatments, which was similar to previous investigations.ResultsSignificant differences in anaerobic peak power relative to the WAnT were observed following ingestion of the SUP (782 ± 191 W) in comparison to the PL (722 ± 208 W; p = 0.003; effect size = 0.30) and BA (723 ± 205 W; p = 0.011; effect size = 0.28). Significant differences were also observed for anaerobic mean power following ingestion of the SUP (569 ± 133 W) in comparison to the PL (535 ± 149 W; p = 0.006; effect size = 0.24) and BA (538 ± 148 W; p = 0.020; effect size = 0.22). No significant differences between trials were observed for upper body power, lower body power, or upper body strength.ConclusionsIngestion of the pre-workout dietary supplement led to significant improvements in anaerobic peak and mean power values in comparison to the placebo and baseline treatments. No improvements were observed in upper and lower body power or upper body strength. Taken prior to exercise, a caffeine-containing pre-workout dietary supplement may improve anaerobic power performance.

Protein adsorption onto the surface of a biomaterial mediates cell adhesion and enhances tissue-implant integration. In a previous study, we demonstrated that crystallization of bioactive glass (BG) significantly increased the negative zeta potential and decreased serum protein adsorption onto the material surface. In this study, the conformation of protein adsorbed onto the surface of amorphous bioactive glass (ABG) and crystallized bioactive glass (CBG) was analyzed and correlated to bone marrow mesenchymal stem cell adhesion and spreading. ABG and CBG were immersed in three different protein solutions containing 10% fetal bovine serum, bovine serum albumin (BSA), and fibronectin (FN) for 4 h at 37 degrees C. Grazing angle Fourier transform infrared spectroscopy (GA-FTIR) demonstrated that the ratio of (amide I)/(amide II) functional groups of all proteins adsorbed onto ABG was greater than that for proteins adsorbed onto CBG. The Gaussian curve fitting analysis suggests that the significant expression of amide I, rich in charged and flexible unordered secondary structure of adsorbed FN, stimulated bone cell adhesion and spreading on the surface of ABG. CBG enforces protein conformation that exposes amide II, rich in neutral and stable beta-sheet structure and alpha-helix, which limited cell adhesion and spreading. Although ABG adsorbed significantly higher quantity of BSA than FN, GA-FTIR analyses showed that the ratio of amide I/amide II was significantly higher for adsorbed FN. Therefore, the intensity of amide I or amide II bands cannot be taken as a measure of the quantity of adsorbed protein.

In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250 MHz.

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Measurement of thiol-disulfide redox status is crucial for characterization of tumor physiology. The electron paramagnetic resonance (EPR) spectra of disulfide-linked dinitroxides are readily distinguished from those of the corresponding monoradicals that are formed by cleavage of the disulfide linkage by free thiols. EPR spectra can thus be used to monitor the rate of cleavage and the thiol redox status. EPR spectra of 1H,14N- and 2H,15N-disulfide dinitroxides and the corresponding monoradicals resulting from cleavage by glutathione have been characterized at 250 MHz, 1.04 GHz, and 9 GHz and imaged by rapid-scan EPR at 250 MHz.