At room temperature, the vapor pressures of desflurane, isoflurane, and sevoflurane are well above the clinically useful range. We hypothesized that therapeutic concentrations of these agents could be achieved at temperatures below 0°C, but the vapor pressure-temperature relationship is unknown below 0. Second, we hypothesized that this relationship could be exploited to deliver therapeutic-range concentrations of anesthetic vapor. We therefore set out to determine the low temperature-vapor pressure relationships of each anesthetic agent, thereby identifying the saturated vapor concentration of each agent at any temperature below 0°C. To test our hypothesis, we measured the saturated vapor concentration at 1 atm of pressure for temperatures between -60 and 0°C, thus developing an empiric relationship for each agent. There was consistency in repeated experiments for all 3 agents. To test the empiric data, we constructed a digitally controlled thermoelectric anesthetic vaporizer, characterized the device, and used it to deliver anesthetic vapor to laboratory mice. We report, for the first time, the temperature-vapor pressure relationship at temperatures below 0°C for desflurane, isoflurane, and sevoflurane as well as the TMAC of these agents: the temperature at which the vapor pressure is equal to the minimum alveolar concentration. We describe the construction and limited validation of an anesthetic vaporizer prototype on the basis of this principle. We conclude that clinically relevant concentrations of volatile anesthetics may be achieved at low temperatures.
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http://dx.doi.org/10.1213/ANE.0000000000001547 | DOI Listing |
Int J Biol Macromol
January 2025
Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, 41012 Sevilla, Spain.
The current study addresses the pressing issue of unsustainable water management, particularly in regions experiencing high water stress. It focuses on examining the viability of polymeric membranes composed of biobased materials, mainly chitosan, for various sustainable water management solutions. The membranes evaluated in the study were blends of PVC with either chitosan-silica or charcoal-silica, designed to enhance their functionality and performance.
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January 2025
Department of Food Science, Federal University of Lavras (UFLA), Lavras 37200-000, Brazil.
The use of active packaging made from biodegradable polymers can contribute to the environment and to the food industry by increasing the shelf life of their products. This study aimed to produce chitosan-based films incorporated with the invertase enzyme (1, 2, 5, 9, and 10 %) as an alternative to avoid sucrose crystallization in the confectionery industry. The optimum activity of the invertase enzyme was observed at 55 °C and pH 5, thus, the films made with the film-forming solution adjusted to pH 5 and dried at 55 °C were compared with those without pH adjustment and dried at room temperature.
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January 2025
Division of Biochemical Technology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi (Bangkhunthian Campus), Bangkok 10150, Thailand. Electronic address:
This study aimed to produce a novel resistant maltodextrin (RMD) from the remaining starch in cassava pulp via pyrodextrinization and enzymatic hydrolysis. The optimum conditions involved a temperature of 180 °C, 0.5 % HCl, and a reaction time of 5 h, resulting in a significant RMD yield (18.
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January 2025
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China; National Engineering Research Center for Fruit and Vegetable Processing, Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China.
This study utilized deep eutectic solvents (DES) based on choline chloride/lactic acid (ChCl/LA) to deconstruct coconut fibers. The effects of DES with different temperatures and molar ratios on the yield of lignin, recovery rate of residues, structural changes in lignin and solid residues, and saccharification efficiency were investigated. The results showed that acidic DES treatment effectively deconstructed the coconut fibers, resulting in a high lignin yield of 68.
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January 2025
Department of Agricultural and Environmental Biotechnology, São Paulo State University (UNESP), School of Agricultural and Veterinarian Sciences, Jaboticabal, São Paulo, Brazil; Institute of Bioenergy Research (IPBEN), Jaboticabal, São Paulo, Brazil. Electronic address:
This study characterized a novel bacterial lipase with high biotechnological potential, focusing on industrial and environmental applications. Bacterial isolates were screened using olive oil as a substrate, and the strain with the highest hydrolytic halo was identified as Burkholderia sp. via 16S rRNA analysis.
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