cores of their glycerol dibiphytanyl glycerol tetraether (GDGT) lipids. Cyclized GDGTs increase membrane packing and stability, which has been shown to help cells survive shifts in temperature and pH. However, the extent of this cyclization also varies with growth phase and electron acceptor or donor limitation. These observations indicate a relationship between energy metabolism and membrane composition. Here we show that the average degree of GDGT cyclization increases with doubling time in continuous cultures of the Sulfolobus acidocaldarius thermoacidophile (DSM 639). This is consistent with the behavior of a Nitrosopumilus maritimus mesoneutrophile, SCM1. Together, these results demonstrate that archaeal GDGT distributions can shift in response to electron donor flux and energy availability, independent of pH or temperature. Paleoenvironmental reconstructions based on GDGTs thus capture the energy available to microbes, which encompasses fluctuations in temperature and pH, as well as electron donor and acceptor availability. The ability of Archaea to adjust membrane composition and packing may be an important strategy that enables survival during episodes of energy stress.

Zhou, H., Chen, J., Li, H., Quan, K., Zhang, Y., Qiu, H., 2020. Imidazolium ionic liquid-enhanced poly(quinine)- modified silica as a new multi-mode chromatographic stationary phase for separation of achiral and chiral compounds. Talanta 211, 120743.

http://www.sciencedirect.com/science/article/pii/S0039914020300345 In this work, a novel imidazolium ionic liquid-functionalized poly(quinine)-modified silica stationary phase (Sil-PQn-MIm) was successfully synthesized via surface radical chain transfer and nucleophilic substitution reaction. The modified silica was confirmed by series of characterizations including Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The multi-mode chromatographic performances of the Sil-PQn-MIm column were investigated by anion-exchange mode for separation of aromatic acid samples, hydrophilic interaction mode for separation of nucleosides/nucleobases and sulfanilamides, and reversed-phase mode for separation of alkylbenzenes, benzene and polycyclic aromatic hydrocarbons (PAHs), and the Tanaka test mixtures, respectively. As expected, compared to the Sil-PQn column only with quinine as functional group, the Sil-PQn-MIm column further modified by imidazolium ionic liquid possessed higher separation performance, especially for the separation of nucleosides/nucleobases. The effects including buffer concentration, pH, organic solvent content and column temperature on chromatographic performance were studied, which proved that multiple interactions including electrostatic, hydrophobic and hydrophilic interactions can be simultaneously existed between the stationary phase and the analytes. In addition, reproducibility and efficiency of the Sil-PQn- MIm column were also investigated, the results illustrated that the stationary phase have good enough reproducibility (RSDs 0.15% - 0.72%, n = 7) and high efficiency (plates per meter, ~90000 plates/m). In conclusion, the prepared stationary phase with multiple-mode retention capabilities could realize separation for various types of samples by optimizing chromatographic conditions, even for some chiral compounds.

Zhou, J., Yang, K., Tian, S., Zhou, L., Xian, X., Jiang, Y., Liu, M., Cai, J., 2020. CO -water-shale interaction 2 induced shale microstructural alteration. Fuel 263, 116642.

http://www.sciencedirect.com/science/article/pii/S0016236119319969 To better understand the CO enhanced shale gas recovery process, it is of great significance to investigate the 2 CO -water-shale interaction and its effect on the microstructural alteration in shale. To clarify the 2 microstructural alteration of shale exposure to CO -water at different CO pressures, X-ray diffraction analysis, 2 2 low-pressure nitrogen gas adsorption (N GA), nuclear magnetic resonance (NMR) and fractal analysis were 2 P carried on shale samples before and after pure water and CO -water ( = 6, 10, 14 MPa; T = 45 °C) 2 CO2 exposure. After CO -water exposure, the contents of quartz in shale were increased, while the content of 2 carbonate and clay minerals in shale were decreased with the increase of CO pressure. With the increase of 2 CO pressure, the total specific surface area (TSSA) in shale were decreased with a maximum reduction of 2 R 29.40%, while the porosity was increased from 2.88% to a range of 2.93%-3.16%. The average pore size ( ) ave in shale was also increased and the pore connectivity in shale was improved, micropores and mesopores in shale D are gradually transferred to macropores. Both the pore surface fractal dimensions obtained from N GA ( ) 2 L1 D D D and NMR ( ), and the pore volume fractal dimensions obtained from N GA ( ) and NMR ( ), were N1 2 L2 N2