Anaesthesia and high altitude: a history.

During an expedition to climb Everest in 1933, expedition doctor Raymond Greene administered an open-drop chloroform anaesthetic to a Tibetan patient at an altitude of more than 14,000 feet. The patient's subsequent apparent cardiopulmonary arrest has long been attributed to the effects of altitude on anaesthetic delivery. However, anaesthetics can be safely administered at a wide variety of altitudes by adequately trained and experienced anaesthetists. The problems may have arisen from an inadequate depth of anaesthesia consequent to decreased chloroform vaporisation in a cold environment, Greene's concern about potential depression of ventilation and the contemporary lack of a precise approach to assessing depth of anaesthesia

Biosorption of Metals and Metalloids

Industrial activities such as mining operations, refining of ores and combustion of fuel oils play a relevant role in environmental pollution since their wastes contain high concentrations of toxic metals that can add significant contamination to natural water and other water sources if no decontamination is previously applied. As toxic metals and metalloids, including arsenic, cadmium, lead, mercury, thallium, vanadium, among others, are not biodegradable and tend to accumulate in living organisms, it is necessary to treat the contaminated industrial wastewaters prior to their discharge into the water bodies. There are different remediation techniques that have been developed to solve elemental pollution, but biosorption has arisen as a promising clean-up and low-cost biotechnology. Biosorption is one of the pillars of bioremediation and is governed by a variety of mechanisms, including chemical binding, ion exchange,physisorption, precipitation, and oxide-reduction. This involves operations(e.g. biosorbent reuse, immobilization, direct analysis of sample without destruction) that can be designed to minimize or avoid the use or generation of hazardous substances that have a negative impact on the environment and biota, thus following the concepts of "green chemistry" and promoting the environmental care. Furthermore, it has to be specially considered that the design of a biosorption process and the quality of a biosorbent are normally evaluated from the equilibrium, thermodynamic, and kinetic viewpoints.Therefore, a successful biosorption process can be only developed based on multidisciplinary knowledge that includes physical chemistry, biochemistryand technology, among other fields.In this chapter, we explain in detail all the aforementioned aspects. State of the art applications of biosorbents for metals and metalloids removal are carefully revised based on a complete analysis of the literature. Thus, it is evidenced in this chapter that the main points to consider regarding biosorption are the type of biomaterial (e.g. bacteria, fungi, algae, plant?derivatives and agricultural wastes, chitin/chitosan based materials) and the presence of a broad set of functional groups on their surface that are effective for the removal of different toxic metals and metalloids. In fact, removal percentages as high as 70-100% can be found in most works reported in the literature, which is demonstrating the excellent performance obtained with biosorbents. Also, biosorbents have evolved with the help of nanotechnology to modern bio-nano-hybrids materials having superlative sorption properties due to their high surface area coming from the nano-materials structures and multifunctional capacity incorporated from the several types of chemical groups of biomaterials. These, as well as other important aspects linked to biosorption are fully covered in the present chapter.Fil: Escudero, Leticia Belén. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Quintas, Pamela Yanina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Dotto, Guilherme L.. Universidade Federal de Santa Maria; Brasi