A dedicated system for in situ testing of gamma ray induced optical absorption and emission in optical materials.

Serious radiation damage due to the high energy neutron/gamma fluxes is expected for optical materials such as scintillators, windows, and lenses which will be part of the plasma diagnostics in future fusion devices. Radiation induced absorption represents a major concern for these components for which experimental validation under as near as possible reactor conditions becomes essential. A new experimental system has been developed at the CIEMAT Nayade 60Co gamma irradiation facility for in situ radiation induced optical absorption measurements, covering a spectral range between 370 and 730 nm. This setup consists in a rotating sample holder which allows one to collect incident light (reference signal) and transmitted light through the material to be tested as a function of irradiation dose. This is an advanced and robust system which overcomes the important experimental difficulties that radiation involves providing a valuable testing capability for transmission components and scintillators under realistic fusion conditions. A detailed description of the experimental arrangement, together with preliminary tests carried out for system validation is given in this paper.

The Durban World Congress Ethics Round Table Conference Report: III. Withdrawing Mechanical ventilation--the approach should be individualized.

PURPOSE: The purpose of this study is to determine the approaches used in withdrawing mechanical ventilator support. MATERIALS AND METHODS: Speakers from the invited faculty of the World Federation of Societies of Intensive and Critical Care Medicine Congress in 2013 with an interest in ethics were asked to provide a detailed description of individual approaches to the process of withdrawal of mechanical ventilation. RESULTS: Twenty-one participants originating from 13 countries, responded to the questionnaire. Four respondents indicated that they do not practice withdrawal of mechanical ventilation, and another 4 indicated that their approach is highly variable depending on the clinical scenario. Immediate withdrawal of ventilation was practiced by a large number of the respondents (7/16; 44%). A terminal wean was practiced by just more than a third of the respondents (6/16; 38%). Extubation was practiced in more than 70% of instances among most of the respondents (9/17; 53%). Two of the respondents (2/17; 12%) indicated that they would extubate all patients, whereas 14 respondents indicated that they would not extubate all their patients. The emphasis was on tailoring the approach used to suit individual case scenarios. CONCLUSIONS: Withdrawing of ventilator support is not universal. However, even when withdrawing mechanical ventilation is acceptable, the approach to achieve this end point is highly variable and individualized.