14 research outputs found
Neurohumoral and metabolic response to exercise in water.
Item does not contain fulltextAtrial natriuretic peptide (ANP) stimulates lipid mobilization and lipid oxidation in humans. The mechanism appears to promote lipid mobilization during exercise. We tested the hypothesis that water immersion augments exercise-induced ANP release and that the change in ANP availability is associated with increased lipid mobilization and lipid oxidation. In an open randomized and cross-over fashion we studied 17 men (age 31+/-3.6 years; body mass index 24+/-1.7 kg/m(2); body fat 17+/-6.7%) on no medication. Subjects underwent two incremental exercise tests on a bicycle ergometer. One test was conducted on land and the other test during immersion in water up to the xiphoid process. In a subset (n=7), we obtained electromyography recordings in the left leg. We monitored gas exchange, blood pressure, and heart rate. In addition, we obtained blood samples towards the end of each exercise step to determine ANP, norepinephrine, epinephrine, lactate, free fatty acids, insulin, and glucose concentrations. Heart rate, systolic blood pressure, and oxygen consumption at the anaerobic threshold and during peak exercise were similar on land and with exercise in water. The respiratory quotient was mildly reduced when subjects exercised in water. Glucose and lactate measurements were decreased whereas free fatty acid concentrations were increased with exercise in water. Water immersion attenuated epinephrine and norepinephrine and augmented ANP release during exercise. Even though water immersion blunts exercise-induced sympathoadrenal activation, lipid mobilization and lipid oxidation rate are maintained or even improved. The response may be explained by augmented ANP release.1 mei 201
Does promethazine (Atosil�) influence the human's early acoustically evoked potentials in the same way as the late potential N1?
Solar Hydrogen Production by Plasmonic Au–TiO<sub>2</sub> Catalysts: Impact of Synthesis Protocol and TiO<sub>2</sub> Phase on Charge Transfer Efficiency and H<sub>2</sub> Evolution Rates
The activity of plasmonic Au–TiO<sub>2</sub> catalysts for
solar hydrogen production from H<sub>2</sub>O/MeOH mixtures was found
to depend strongly on the support phase (anatase, rutile, brookite,
or composites thereof) as well as on specific structural properties
caused by the method of Au deposition (sol-immobilization, photodeposition,
or deposition–precipitation). Structural and electronic rationale
have been identified for this behavior. Using a combination of spectroscopic
in situ techniques (EPR, XANES, and UV–vis spectroscopy), the
formation of plasmonic Au particles from precursor species was monitored,
and the charge-carrier separation and stabilization under photocatalytic
conditions was explored in relation to H<sub>2</sub> evolution rates.
By in situ EPR spectroscopy, it was directly shown that abundant surface
vacancies and surface OH groups enhance the stabilization of separated
electrons and holes, whereas the enrichment of Ti<sup>3+</sup> in
the support lattice hampers an efficient electron transport. Under
the given experimental conditions, these properties were most efficiently
generated by depositing gold particles on anatase/rutile composites
using the deposition–precipitation technique