Abstract: A method is disclosed for separating compressed dry air to provide carbon dioxide and reduced-carbon dioxide compressed dry air. The method comprises providing a source of compressed dry air and admitting compressed dry air into a first chamber containing a carbon dioxide-adsorbent material at a first temperature. The carbon dioxide-adsorbent material adsorbs carbon dioxide from the compressed dry air to form reduced-carbon dioxide compressed dry air, which is allowed to pass out of the first chamber. The first chamber is closed to the source of compressed dry air. Then the carbon dioxide-adsorbent material is heated to a second temperature. This releases carbon dioxide from the carbon dioxide-adsorbent material, which carbon dioxide is removed from the first chamber. The method may be low cost and low energy, and may be easily integrated into existing compressed dry air systems.

Abstract: Ratios of measured values of glucose, citrate, and cis-aconitate in a biological sample obtained from a subject to measured values of glucose, citrate, and cis-aconitate in a biological sample obtained from a healthy subject are calculated, and the glucose ratio, the citrate ratio, and the cis-aconitate ratio are used to evaluate and/or assess fatigue. Similarly, an isocitrate ratio, a succinate ratio, a malate ratio, and a lactate ratio are calculated, and these ratios are used together with the three ratios to evaluate and/or assess fatigue. This makes it possible to objectively and easily diagnose and evaluate fatigue.