https://doi.org/10.1089/ast.2019.2082 Extreme factors such as space microgravity, radiation, and magnetic field differ from those that occur on Earth. Microgravity may induce and select some microorganisms for physiological, metabolic, and/or genetic variations. This study was conducted to determine the effects of simulated microgravity conditions on the Lactobacillus reuteri metabolism and gene expression of the probiotic bacterium DSM17938. To investigate microbial response to simulated microgravity, two devices - the rotating wall vessel (RWV) and the random positioning machine (RPM) - were used. Microbial growth, reuterin production, and resistance to gastrointestinal passage were assessed, and morphological characteristics were analyzed by scanning electron microscopy. The expression of some selected genes that are responsive to stress conditions and to bile salts stress was evaluated through real-time quantitative polymerase chain reaction assay. Monitoring of bacterial g growth, cell size, and shape under simulated microgravity did not reveal di fferences compared with 1 × controls. On the contrary, an enhanced production of reuterin and a greater tolerance to the gastrointestinal passage were observed. Moreover, some stress genes were upregulated under RWVconditions, especially after 24 h of treatment, whereas RPM conditi ons seemed to determine a downregulation over time of the same stress L. genes. These results show that simulated microgravity could alter some physiological characteristics of reuteri DSM17938 with regard to tolerance toward stress conditions encountered on space missions and could be useful to elucidate the adaptation mechanisms of microbes to the space environment.

Sharma, V., Sircar, A., 2020. Multi-technique characterization of shale reservoir quality parameters. Journal of Natural Gas Science and Engineering 75, 103125.

http://www.sciencedirect.com/science/article/pii/S1875510019303774 A multitechnique characterization approach has been used to quantitatively and qualitatively evaluate all the reservoir quality parameters, crucial for the exploitation and development of unconventional shale plays. Characterization methods, in particular FTIR, XRF, NMR, MICP, HPP, LPP and High Pressure Permeameter were used on selected 20 younger and older shale samples of Cambay to determine their true petrophysics, mineralogy, brittleness and fracability potential with respect to depth. Properties mainly porosity, permeability, pore size distribution, mineralogy, brittleness, pore sizes and fracability were determined. It was found that younger cambay has medium size pores with high porosity, low silica and high clay content. On the contrary, older cambay has good pore connectivity, rich in organic and clay content, fair brittleness index and capable of producing hydrocarbons. The performed multidisciplinary analysis is first of its kind research and will go a long way in shale gas research and development in India at pilot scale. The generated data can be helpful in minimizing the research gap and hence the challenges associated with the commercial development of these prolific shales.

Shen, P., Li, G., Li, B., Li, X., Liang, Y., Lv, Q., 2020. Permeability measurement and discovery of dissociation process of hydrate sediments. Journal of Natural Gas Science and Engineering 75, 103155.

http://www.sciencedirect.com/science/article/pii/S1875510020300093 The study on the permeability of methane hydrates in fine quartz sands contributes to the accurate prediction of gas/water production and can effectively express the characteristics of fluid migration. In this study, the water k effective permeability ( ) of methane hydrates in three fine quartz sands containing various hydrate saturation w S ( ) were carried out under steady water injection and production. Experimental results indicated that the effect H k of particle sizes on was significant even though the difference in the average particle size of three fine quartz w sands was relatively limited. The differential pressure of the hydrate sediments was completely recorded during permeability measurement, and the stabilization and decomposition process of hydrate could be clearly k represented by differential pressure. The increased rapidly with the decomposition of hydrate and the w appearance of flow channel in the hydrate sediments. Hydrate dissociation process was recorded in situ by Cold Field Emission Scanning Electron Microscopy (CFE - SEM), the dissociation of hydrates in pore space was clearly visible, and the hydrates in pore space were first dissociated into many small regions. A new reduction k S model between water relative permeability ( ) and was proposed on the basis of experimental results, and rw H k the experimental data fitted well with hydrates occupying pore centers. The effect of particle sizes on was rw