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The evaporation and the thermal accommodation coefficients for water in nitrogen were investigated by means of the analysis of evaporation of pure water droplet as a function of temperature. The droplet was levitated in an electrodynamic trap placed in a climatic chamber. The levitation time was in the range of seconds, which corresponds to the characteristic time scales of cloud droplet growth. Droplet radius evolution and evaporation dynamics were studied as a function of temperature, by analyzing the angle-resolved light scattering Mie interference patterns. A model of droplet evolution, accounting for the kinetic effects near the droplet surface, was applied. The evaporation coefficient for the temperature range from 273.6 to 298.3 K was found to be between 0.054 and 0.12 with a minimum of 0.036 [+ or -] 0,015 seemingly coinciding with water maximum density at 277.1 K. The average value of thermal accommodation coefficient over the temperature range from 277 to 289 K was found to be 0.7 [+ or -] 0.2.

The evaporation coefficients of water in air and nitrogen are found as a function of temperature by analyzing the evaporation of a pure water droplet. The evaporation coefficient [alpha] in air and in nitrogen are shown to be equal and the average value of the thermal accomodation coefficient over the same temperature range is shown to be 1 +-0.05.

OBJECTIVES: It is suggested that gut microbiota play a role in the pathogenesis of obesity enhancing energy utilization from digested food. The influence of gut microbiota on resting energy expenditure (REE) has not been evaluated yet. AIM: The aim of the study is to assess the composition on gut microbiota and its association with REE in obese and normal weight subjects. SUBJECTS AND METHODS: REE measurement and semi-quantitative analysis of gut microbiota composition in aerobic and anaerobic conditions were performed in 50 obese and 30 normal weight subjects without concomitant diseases. RESULTS: A count of bacterial colony was greater in obese than in normal weight subjects. However, the proportion of Bacteroides spp. and Firmicutes was similar in both study groups. A positive correlation between REE (kcal/d) and total bacterial count (r = 0.26, p < 0.05), as well as between REE and the percentage of Firmicutes (r = -0.24, p < 0.05) was found. The multiple regression analysis did not prove an independent impact of total bacterial as well as Bacteroides spp. and Firmicutes counts on REE. CONCLUSIONS: The composition of gut microbiota is not associated with the level of resting energy expenditure. The proportion of Bacteroides and Firmicutes in gut microbiota is not related to body mass. [ABSTRACT FROM AUTHOR]