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The proton transport in one-dimensional (1D) confined water chains has been extensively studied as a model for ion channels in cell membrane and fuel cell. However, the mechanistic understanding of the proton transfer (PT) process in 1D water chains remains incomplete. In this study, we demonstrate that the two limiting structures of the hydrated excess proton, H5O2+ (Zundel) and H3O+ (linear H7O3+), undergo a change in dominance as the water chain grows, causing two co-existing and opposing PT mechanisms. Specifically, H5O2+ is stable in the middle of the chain, whereas H3O+ serves as a transition state (TS). Except for this region, H3O+ is stabilized while H5O2+ serves as a TS. The interaction analysis shows that the electrostatic interaction plays a crucial role in the difference in PT mechanisms. Our work fills a knowledge gap between the various PT mechanisms reported in bulk water and long 1D water chains, contributing to a deeper understanding of biological ion channels at the atomic level. [ABSTRACT FROM AUTHOR]

The paleovegetation and paleoclimate characteristics are studied in the Palaeogene strata of Hetao Basin, Subei Basin and Qaidam Basin in China, and the Cretaceous Guyang Formation (K1g) in the Hetao Basin. These three basins receive high attention, different distribution areas, representative. Pollen evidence shows that: (1) The sporopollen assemblage of Palaeogene Linhe Formation (E3l) in Hetao Basin is characterised by Pinaceae-Ephedripites-Ulmipollenites-Chenopodipollis. It reflects that the ancient vegetation types were mainly coniferous and evergreen woody plants, and the climate was cold temperature. The sporopollen assemblage characteristics of the upper member of the Palaeogene Xiaganchaigou Formation (E32) in the Qaidam Basin are similar to it. (2) The sporopollen characteristics of the K1g in the Hetao Basin reflect that its ancient vegetation was dominated by evergreen woody plants and belongs to a warm and humid subtropical climate. (3) The assemblage of Palaeocene Funing Formation (E1f) in Subei Basin was Pterisisporites undulatus-Ulmipollenites minor-Taxodiaceaepollenites hiatus. The climate type was humid north temperate climate, vegetation was mainly deciduous trees and evergreen woody plants. (4) Leiosphaeridia/Granodiscus, Pediastrum and Botryococcus were also detected in the E1f of Subei Basin. The appearance of these algae indicates the special saline water environment and good hydrocarbon potential. [ABSTRACT FROM AUTHOR]

The well-developed mudstone and gypsum mudstone in the Oligocene Linhe Formation (E3l) in the Hetao Basin are the main source rocks for gypsum. However, the sedimentary environment and organic matter (OM) enrichment factors of E3l are not clear, and this inhibits the prediction of hydrocarbon source rock distribution and resource calculation. Major and trace elements, total organic carbon (TOC), pyrolysis using the Rock-Eval II, and saturated hydrocarbon gas chromatography–mass spectrometry (GC–MS) analyses were performed in this study. The results show that E3l was deposited in brackish water and saline–ultrasaline water, with weak oxidation reduction in an arid and hot environment. Terrestrial input inhibits OM enrichment, while the redox, paleosalinity, paleoclimate, and paleoproductivity play a catalytic role. The main controlling factors of the same lithologic source rocks are different: terrestrial input and paleoclimate have a greater impact on mudstone, and the redox and paleosalinity were more favorable to gypsum mudstone. Although the main controlling factors are different for different lithologies, their OM enrichment characteristics are still consistent. The E3l water body was deep, and the contribution of nutrients from terrigenous debris to OM enrichment was less. In addition, the water retention environment changed significantly during the E3l sedimentary period, resulting in fewer nutrients, which limited the improvement of surface water paleoproductivity. The arid climate increased water evaporation and salinity, which to some extent prevented consumption and decomposition. Weak oxidation-reduction fluctuations and the stratification of the water body were obvious, and this was not only conducive to the enrichment of OM but also to its preservation. [ABSTRACT FROM AUTHOR]

Abstract: Although hydrogen bonds are relatively weak, they play essential roles in life processes. Through cooperative effects, these weak bonds exhibit a significant influence on the structure, function and dynamics of biomolecules. In this work, we study the internal mechanism of cooperativities, involving collective electron and nuclear motions, in multiple H‐bonding glycine‐(H2O)n (n = 2 or 3) clusters, using first‐principles calculations. Multiplex molecular orbitals aid the coherent carrier‐transport through orbital‐penetrating. In addition, the infrared spectra and nuclear vibrating patterns reveal that the H‐bond donor stretching modes exhibit significant connections across neighboring hydrogen bonds. However, when the anharmonic nuclear motions are taken into account, the cooperative effects are partially ruined due to the nonsynchronized nuclei activities. Additionally, the cooperative contributions to the H‐bonding interaction energies are also evaluated. These results give descriptions of cooperativities of multiple hydrogen bonds and provide a more comprehensive insight into conventional intermolecular hydrogen bonding. [ABSTRACT FROM AUTHOR]