A Voltage-Responsive Synthetic Cl−-Channel Regulated by pH

Transmembrane protein channels are an important inspiration for the design of artificial ion channels. Their dipolar structure helps overcome the high energy barrier to selectively translocate water and ions sharing one pathway, across the cell membrane. Herein, we report that the amino-imidazole (Imu) amphiphiles self-assemble via multiple H-bonding to form stable artificial Cl⁻-channels within lipid bilayers. The alignment of water/Cl⁻ wires influences the conduction of ions, envisioned to diffuse along the hydrophilic pathways; at acidic pH, Cl⁻/H⁺ symport conducts along a partly protonated channel, while at basic pH, higher Cl⁻/OH⁻ antiport translocate through a neutral channel configuration, which can be greatly activated by applying strong electric field. This voltage/pH regulated channel system represents an unexplored alternative for ion-pumping along artificial ion-channels, parallel to that of biology.     

“原子结构”教学中引入哲学理念

The structural discovery and understanding of atoms are a microcosm of the process of human cognition and a concrete practice of materialistic dialectics and methodology, which contains a wealth of dialectical thought. The "atomic structure" chapter (section) in inorganic chemistry course is a difficult part for the first-year undergraduates to understand. The introduction of philosophical idea into the teaching process of this chapter (section) will not only help them learn and master chemistry, but also help them establish a correct world view and methodology.     

金色梦想，一触即发——化学专业校外实践教学基地建设与思考

高等教育要适应世界潮流和时代变化,本科教育须进一步提高实践教学的比重,加强理论教学与实践教学相结合,完善协同育人机制。结合学科发展和企业发展需求,中山大学化学学院与金发科技股份有限公司(简称金发科技)共同建设大学生实践教学基地。本文以中山大学-金发科技本科实践教学基地为例,探讨大学生校外实践基地建设过程中遇到的问题以及实践基地的建设内容与成果体会。     

Fatigue Behavior of Composite Sandwich Panels Under Three Point Bending Load

In this paper, the bending fatigue tests of honeycomb sandwich panels are carried out by using an improved three-point bending test fixture, and the S-N curves at different stress ratios are obtained. Through the records of fatigue damage in the experiment, the failure mode of the honeycomb sandwich panels and the source of fatigue damage are determined. At the same time, through the calculation of the shear stress distribution on the honeycomb wall, the reasons for the difference in the failure morphology of the L-direction and W-direction sandwich panels are clarified. Besides, a life prediction method is proposed and its effectiveness in predicting the fatigue life of sandwich panels has been verified.     

1,2-Diketones as photoinitiators of both cationic and free-radical photopolymerization under UV (392 nm) or Blue (455 nm) LEDs

The photoinitiation abilities of three 1,2-diketones [i.e., acenaphthenequinone ( ANPQ ), aceanthrenequinone ( AATQ ), and 9,10-phenanthrenequinone ( PANQ )]-based photoinitiating systems [PISs, with additives such as iodonium salt, N-vinylcarbazole (NVK), tertiary amine, and phenacyl bromide (R-Br)] for cationic photopolymerization and free-radical photopolymerization under the irradiation of ultraviolet (UV; 392 nm) or blue (455 nm) light-emitting diode (LED) bulb are investigated. All 1,2-diketones studied exhibit ground state absorption that match with the emission spectra of UV (392 nm) or blue LED (455 nm) better than that of the well-known blue-light-sensitive photoinitiator camphorquinone (CQ). In particular, AATQ /iodonium salt/NVK can show high photoinitiating ability (with epoxide conversion yield >70%) under the UV light irradiation due to the effect of NVK. In addition, 1,2-diketone/iodonium salt (and optional NVK) systems are capable of initiating free-radical photopolymerization of methacrylates, with conversions of 50–58%. Furthermore, some 1,2-diketone/tertiary amine (and optional R-Br) combinations are found to demonstrate high efficiency to initiate free-radical photopolymerization, and 71% of methacrylate conversion can be achieved with PANQ /tertiary amine/R-Br PIS. Some 1,2-ketone-based PISs can even exhibit higher efficiency than the CQ-based systems. The photochemical mechanism of the radical generation from the 1,2-diketone-based PISs is investigated and found to be consistent with the related photopolymerization efficiency. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 792–802     

Unlocking the Drug Potential of the Bryostatin Family: Recent Advances in Product Synthesis and Biomedical Applications

Bryostatins are a class of naturally occurring macrocyclic lactones with a unique fast developing portfolio of clinical applications, including treatment of AIDS, Alzheimer's disease, and cancer. This comprehensive account summarizes the recent progress (2014–present) in the development of bryostatins, including their total synthesis and biomedical applications. An emphasis is placed on the discussion of bryostatin 1 , the most-studied analogue to date. This review highlights the synthetic and biological challenges of bryostatins and provides an outlook on their future development.     

Hierarchical Hollow-Nanocube Ni−Co Skeleton@MoO3/MoS2 Hybrids for Improved-Performance Lithium-Ion Batteries

Improving the performance of anode materials for lithium-ion batteries (LIBs) is a hotly debated topic. Herein, hollow Ni−Co skeleton@MoS₂/MoO₃ nanocubes (NCM-NCs), with an average size of about 193 nm, have been synthesized through a facile hydrothermal reaction. Specifically, MoO₃/MoS₂ composites are grown on Ni−Co skeletons derived from nickel–cobalt Prussian blue analogue nanocubes (Ni−Co PBAs). The Ni−Co PBAs were synthesized through a precipitation method and utilized as self-templates that provided a larger specific surface area for the adhesion of MoO₃/MoS₂ composites. According to Raman spectroscopy results, as-obtained defect-rich MoS₂ is confirmed to be a metallic 1T-phase MoS₂. Furthermore, the average particle size of Ni−Co PBAs (≈43 nm) is only about one-tenth of the previously reported particle size (≈400 nm). If assessed as anodes of LIBs, the hollow NCM-NC hybrids deliver an excellent rate performance and superior cycling performance (with an initial discharge capacity of 1526.3 mAh g⁻¹ and up to 1720.6 mAh g⁻¹ after 317 cycles under a current density of 0.2 A g⁻¹). Meanwhile, ultralong cycling life is retained, even at high current densities (776.6 mAh g⁻¹ at 2 A g⁻¹ after 700 cycles and 584.8 mAh g⁻¹ at 5 A g⁻¹ after 800 cycles). Moreover, at a rate of 1 A g⁻¹, the average specific capacity is maintained at 661 mAh g⁻¹. Thus, the hierarchical hollow NCM-NC hybrids with excellent electrochemical performance are a promising anode material for LIBs.     

Two-Dimensional Germanium Sulfide Nanosheets as an Ultra-Stable and High Capacity Anode for Lithium Ion Batteries

Lithium ion batteries (LIBs) at present still suffer from low rate capability and poor cycle life during fast ion insertion/extraction processes. Searching for high-capacity and stable anode materials is still an ongoing challenge. Herein, a facile strategy for the synthesis of ultrathin GeS₂ nanosheets with the thickness of 1.1 nm is reported. When used as anodes for LIBs, the two-dimensional (2D) structure can effectively increase the electrode/electrolyte interface area, facilitate the ion transport, and buffer the volume expansion. Benefiting from these merits, the as-synthesized GeS₂ nanosheets deliver high specific capacity (1335 mAh g⁻¹ at 0.15 A g⁻¹), extraordinary rate performance (337 mAh g⁻¹ at 15 A g⁻¹) and stable cycling performance (974 mAh g⁻¹ after 200 cycles at 0.5 A g⁻¹). Importantly, our fabricated Li-ion full cells manifest an impressive specific capacity of 577 mAh g⁻¹ after 50 cycles at 0.1 A g⁻¹ and a high energy density of 361 Wh kg⁻¹ at a power density of 346 W kg⁻¹. Furthermore, the electrochemical reaction mechanism is investigated by the means of ex-situ high-resolution transmission electron microscopy. These results suggest that GeS₂ can use to be an alternative anode material and encourage more efforts to develop other high-performance LIBs anodes.