JET divertor diagnostic upgrade for neutral gas analysis.

With installation of the ITER-like wall in JET a major diagnostic upgrade to measure the neutral gas pressure and composition in the sub-divertor region has been completed, to characterise retention and outgassing of the new metallic first wall. The upgrade includes two new magnetically shielded systems consisting of sensitive capacitance manometers and residual gas analysers, both capable of providing data during plasma operation. These enable absolute pressure and gas composition measurements (pressure range: 10(-5)-10(-1) mbar, mass range: 1-200 amu, respectively) and have been used to characterise the neutral gas behaviour under various plasma conditions.

Ascorbate reduces superoxide production and improves mitochondrial respiratory chain function in human fibroblasts with electron transport chain deficiencies.

The present paper attempts to ascertain the role of ascorbate on the generation of superoxide radicals in skin fibroblasts of patients with deficiency of mitochondrial respiratory chain enzymes. Fibroblast cell lines were grown with or without ascorbate for the last 48 h of their growth period. The amount of superoxide radical production in cells was measured by the reduction of nitroblue tetrazolium and the activities of respiratory chain enzymes were examined in isolated fibroblast mitochondria. The results indicated a significant inverse correlation between the amount of superoxide radicals and the specific activities of complexes I-III and II-III of the respiratory chain. The ascorbate treatment of fibroblasts from control subjects did not show any effect on either superoxide radical production or respiratory chain enzymes' activities. While in patient's fibroblasts, this vitamin significantly decreased the superoxide radicals and increased the specific activities of I-III and II-III complexes but not complex IV. These observations indicate that superoxide radicals are increased in patients with deficient respiratory chain enzymes in their fibroblasts and ascorbate can prevent the loss of these enzymes by acting on the selected sites in the respiratory chain, which are related to the production of free radicals.

Intraoperative evoked potentials: an overview.

Over the past decade the application of neurophysiologic monitoring techniques has been a major factor in decreasing the incidence of neurologic dysfunction following orthopedic, vascular, and neurosurgical operations. This article focuses on the common neurophysiologic monitoring modalities and their basic intraoperative applications.

Mode structure in the unstable resonator of an optically pumped FIR laser: an investigation.

In this paper we investigate the mode structure in an unstable optically pumped FIR oscillator as a function of the pump beam uniformity. It is shown that the effective output coupling is sensitively dependent on the pump beam intensity profile and the degree of saturation. As an example a telescopic D(2)O resonator of nominally 75% output coupling is discussed. The mode structure varies from a stable configuration with zero loss in the small signal range to saturated intensity distributions with output coupling factors exceeding the geometrical value.