16 research outputs found
The use of infrared thermography to detect the skin temperature response to physical activity
Physical activity has a noticeable effect on skin blood flow and temperature. The
thermal regulatory and hemodynamic processes during physical activity are controlled by two
conflicting mechanisms: the skin vasoconstriction induced by the blood flow demand to active
muscles and the skin vasodilation required by thermoregulation to increase warm blood flow
and heat conduction to the skin. The time-evolution of skin temperature during exercise can
give useful information about the adaptation of the subject as a function of specific type,
intensity and duration of exercise. In this paper, infrared thermography is used to investigate
the thermal response of skin temperature during running exercise on treadmill for a group of
seven healthy and trained runners. Two different treadmill exercises are considered: a graded
load exercise and a constant load exercise; for both exercises the duration was 30 minutes.
Within the limits due to the relatively small size of the sample group, results typically indicate
a fall in skin temperature during the initial stage of running exercise. As the exercise
progresses, the dynamics of the skin temperature response depends on the type of exercise
(graded versus constant load) and probably on the level of training of the subject
Acute and constitutive increases in central serotonin levels reduce social play behaviour in peri-adolescent rats
Item does not contain fulltextRATIONALE: Serotonin is an important modulator of social behaviour. Individual differences in serotonergic signalling are considered to be a marker of personality that is stable throughout lifetime. While a large body of evidence indicates that central serotonin levels are inversely related to aggression and sexual behaviour in adult rats, the relationship between serotonin and social behaviour during peri-adolescence has hardly been explored. OBJECTIVE: To study the effect of acute and constitutive increases in serotonin neurotransmission on social behaviour in peri-adolescent rats. MATERIALS AND METHODS: Social behaviour in peri-adolesent rats (28-35 days old) was studied after genetic ablation of the serotonin transporter, causing constitutively increased extra-neuronal serotonin levels, and after acute treatment with the serotonin reuptake inhibitor fluoxetine or the serotonin releasing agent 3,4-methylenedioxymethamphetamine (MDMA). A distinction was made between social play behaviour that mainly occurs during peri-adolescence, and non-playful social interactions that are abundant during the entire lifespan of rats. RESULTS: In serotonin transporter knockout rats, social play behaviour was markedly reduced, while non-playful aspects of social interaction were unaffected. Acute treatment with fluoxetine or MDMA dose-dependently inhibited social play behaviour. MDMA also suppressed non-playful social interaction but at higher doses than those required to reduce social play. Fluoxetine did not affect non-playful social interaction. CONCLUSIONS: These data show that both acute and constitutive increases in serotonergic neurotransmission reduce social play behaviour in peri-adolescent rats. Together with our previous findings of reduced aggressive and sexual behaviour in adult serotonin transporter knockout rats, these data support the notion that serotonin modulates social behaviour in a trait-like manner
Kinetics of malachite leaching in alkaline glycine solutions
Aqueous alkaline glycine solutions present technical advantages over acidic solutions for leaching oxidised copper minerals hosted in carbonate mineral matrix phases. In this study, the leaching and kinetics of malachite in alkaline glycine solutions have been studied. The influence of process variables such as glycine concentration, temperature, particle size and stirring speed on leaching kinetics was evaluated. The results show that temperature has a significant effect on copper dissolution rates. A temperature increase from 25°C to 50°C resulted in a copper extraction of 32.3–83.6% respectively over 5 min. Increasing glycine concentration and reducing particle size led to an increase in copper extraction rates while no significant influence was observed with stirring speeds above 350 rpm