Directional Potassium Transport through a Unimolecular Peptide Channel

Three unimolecular peptide channels have been designed and prepared by using the β‐helical conformation of gramicidin A (gA). The new peptides bear one to three NH₃⁺ groups at the N‐end and one to three CO₂^? groups at the C‐end. These zwitterionic peptides were inserted into lipid bilayers in an orientation‐selective manner. Conductance experiments on planar lipid bilayers showed that this orientation bias could lead to observable directional K⁺ transport under multi‐channel conditions. This directional transport behavior can further cause the generation of a current across a planar bilayer without applying a voltage. More importantly, in vesicles with identical external and internal KCl concentrations, the channels can pump K⁺ across the lipid bilayer and cause a membrane potential.     

The wax deposition rate of water-in-crude oil emulsions based on the laboratory flow loop experiment

This paper aims to develop a mathematical model to predict the wax deposition rate of waxy crude emulsions, combining heat and mass transfer mechanisms. According to the flow loop experimental results, the wax deposition rate increases with the decreasing average temperature of oil/wall in a manner of linear regularity, and shows a downtrend with the increase of water cut due to diffusion resistance. An applicable model is developed regarding emulsion properties, radial temperature gradient, shear stress, and wax diffusion coefficient. In model validation, the prediction results are in good agreement with experimental data with the relative errors within 28.87%.     

Beyond Clusters: Supramolecular Networks Self‐Assembled from Nanosized Silver Clusters and Inorganic Anions

Assembly of small clusters into rigid bodies with precise shape and symmetry has been witnessed by the significant advances in cluster‐based metal–organic frameworks (MOFs), however, nanosized silver cluster based MOFs remain largely unexplored. Herein, two anion‐templated silver clusters, CO₃@Ag₂₀ and SO₄@Ag₂₂, were ingeniously incorporated into a 2D sql lattice ( 1 , [CO₃@Ag₂₀(iPrS)₁₀(NO₃)₈(DMF)₂]_n) and an unprecedented 3D two‐fold interpenetrated dia network ( 2 , [SO₄@Ag₂₂(iPrS)₁₂(NO₃)₆ ? 2 NO₃]_n), respectively, under mild solvothermal conditions. Their atomically precise structures were confirmed by single‐crystal X‐ray diffraction analysis and further consolidated by IR spectroscopy, thermogravimetric analysis (TGA), and elemental analysis. Each drum‐like CO₃@Ag₂₀ cluster is extended by twelve NO₃^? ions to form the 2D sql lattice of 1 , whereas each ball‐shaped SO₄@Ag₂₂ cluster with a twisted truncated tetrahedral geometry is pillared by four [Ag₆(NO₃)₃] triangular prisms to form the 3D interpenetrated dia network of 2 . Notably, 2 is the first interpenetrated 3D MOF constructed from silver clusters. These results demonstrate the dual role of the anions, which not only internally act as anion templates to induce the formation of silver thiolate clusters but also externally extend the cluster units into the rigid networks. The photoluminescent and electrochemical properties of 2 are discussed in detail.     

Synthesis and biological evaluation of echinocystic acid derivatives as HCV entry inhibitors

A series of echinocystic acid (EA) 28-COOH derivatives was synthesized, and their anti-HCV entry activity was evaluated by HCVpp and VSVpp entry assay. It was found that some of them showed moderate anti-HCV entry activity, especially compound 12, and these modifications also removed the undesired hemolytic effect.     

Effects of preparation methods on the performance of Cu-Mo-Fe-Ox in the hydrogen production from water

Two Cu-Mo-Fe-Ox samples, which can store and supply pure hydrogen through repeated redox reaction (Fe3O4+4H23Fe+4H2O), were prepared by co-precipitation (FCM-C) and impregnation (FCM-I) methods, respectively, and the performance of hydrogen production from water were investigated. Compared with the impregnated sample, the co-precipitation sample presented better catalytic activity. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and temperature-programmed reduction (H2-TPR) techniques. XRD, FE-SEM and XPS results suggest that the FCM-C sample has smaller particle size and higher dispersion of iron oxide than that of FCM-I sample. In addition, FT-IR and H2-TPR analyses indicate that the weak interaction among metal oxides in FCM-C sample may induce facile reduction of active metal and superior property of hydrogen production by decomposing water in succession.     

Study on the chemical constituents of the South China Sea gorgonian Junceella juncea

A new steroidal glycoside--4'-O-acetyl-3-O-[beta-D-arabino-pyranosyl-oxy]-cholest-5-ene-3beta,19-diol (1), and a new glycerol derivative--1,2-O-[2'-hydroxyoctadecyl]-glycerol (2), along with 16 known compounds were isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian coral Junceella juncea. The structures of 1 and 2 were established by extensive spectroscopic analysis, including 1D and 2D NMR data.