Effects of obesity on posture and walking: study prior to and following surgically induced weight loss.

BACKGROUND: We investigate whether in severely obese people a marked weight loss may influence individual postural control and motor activities and then reverse the alterations caused by the extra load of body mass. Recent studies have shown that most severely obese patients have various degrees of impairment of postural control, but only a few studies considered those subjects before and after a marked weight loss. METHODS: Ten obese and ten subjects of average weight took part in our experiment. The subjects were requested to perform four different tasks. All obese patients repeated the tasks 1 year after undergoing bariatric surgery. RESULTS: We have found differences between obese and normal-weight people in the execution of all four work tasks. However, a year after surgery, obese patients showed a change in the execution of only two tasks, keeping the same performance in the other two. CONCLUSIONS: The excess of fat mass alters the execution of some tasks, as confirmed by the improvement obtained after weight loss. For other work tasks, we can hypothesize that the neurophysiological plasticity of the neuro-muscular system would require more time to adapt.

Analytical characterisation of a capacitively coupled plasma torch with a central tube electrode.

A new type of radiofrequency capacitively coupled plasma torch is presented. The torch electrode geometry is coaxial with a tubular central electrode and one or two outer ring electrodes. The argon plasma is generated at 275 W radiofrequency power and 27.12 MHz and it has a very good stability and a low gas consumption of 0.4 l min(-1). The nebulized sample is introduced through the tubular electrode into the core of the annular shaped plasma thus achieving a better atomisation and a lower background. The limits of detection for 20 elements are in the range of ng ml(-1) and the dynamic range between 2.5 and 3.5. The best results are obtained with the torch with two outer ring electrodes.

Analytical performance of an r.f. capacitively coupled plasma for atomic emission with tip-ring electrode geometry.

A low to medium power radiofrequency capacitively coupled plasma is characterized as spectral source for atomic emission. The signal to background ratio and the limits of detection were determined for 19 elements as a function of the plasma torch geometry and the observation point.