Comparison of Ferroptosis-Inhibitory Mechanisms between Ferrostatin-1 and Dietary Stilbenes (Piceatannol and Astringin)

Synthetic arylamines and dietary phytophenolics could inhibit ferroptosis, a recently discovered regulated cell death process. However, no study indicates whether their inhibitory mechanisms are inherently different. Herein, the ferroptosis-inhibitory mechanisms of selected ferrostatin-1 (Fer-1) and two dietary stilbenes (piceatannol and astringin) were compared. Cellular assays suggested that the ferroptosis-inhibitory and electron-transfer potential levels decreased as follows: Fer-1 >> piceatannol > astringin; however, the hydrogen-donating potential had an order different from that observed by the antioxidant experiments and quantum chemistry calculations. Quantum calculations suggested that Fer-1 has a much lower ionization potential than the two stilbenes, and the aromatic N-atoms were surrounded by the largest electron clouds. By comparison, the C4′O-H groups in the two stilbenes exhibited the lowest bond disassociation enthalpies. Finally, the three were found to produce corresponding dimer peaks through ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry analysis. In conclusion, Fer-1 mainly depends on the electron transfer of aromatic N-atoms to construct a redox recycle. However, piceatannol and astringin preferentially donate hydrogen atoms at the 4′-OH position to mediate the conventional antioxidant mechanism that inhibits ferroptosis, and to ultimately form dimers. These results suggest that dietary phytophenols may be safer ferroptosis inhibitors for balancing normal and ferroptotic cells than arylamines with high electron-transfer potential.     

Aggregation-Induced Emission by Molecular Design: A Route to High-Performance Light-Emitting Electrochemical Cells

The emission efficiency of organic semiconductors (OSCs) often suffers from aggregation caused quenching (ACQ). An elegant solution is aggregation-induced emission (AIE), which constitutes the design of the OSC so that its morphology inhibits quenching π–π interactions and non-radiative motional deactivation. The light-emitting electrochemical cell (LEC) can be sustainably fabricated, but its function depends on motion of bulky ions in proximity of the OSC. It is therefore questionable whether the AIE morphology can be retained during LEC operation. Here, we synthesize two structurally similar OSCs, which are distinguished by that 1 features ACQ while 2 delivers AIE. Interestingly, we find that the AIE-LEC significantly outperforms the ACQ-LEC. We rationalize our finding by showing that the AIE morphology remains intact during LEC operation, and that it can feature appropriately sized free-volume voids for facile ion transport and suppressed non-radiative excitonic deactivation.     

Electronegativities of elements in covalent crystals

A new electronegativity table of elements in covalent crystals with different bonding electrons and the most common coordination numbers is suggested on the basis of covalent potentials of atoms in crystals. For a given element, the electronegativity increases with increasing number of bonding electrons and decreases with increasing coordination number. Particularly, the ionicity of a covalent bond in different environments can be well-reflected by current electronegativity values; that is, the ionicity of chemical bonds increases as the coordination number of the bonded atoms increases. We show that this electronegativity scale can be successfully applied to predict the hardness of covalent and polar covalent crystals, which will be very useful for studying various chemical and physical properties of covalent materials.     

3D coordination framework [Ln(4)(mu(3)-OH)(2)Cu(6)I(5)(IN)(8)(OAc)(3)] (IN = isonicotinate): employing 2D layers of lanthanide wheel clusters and 1D chains of copper halide clusters

Two novel 3D heterometallic coordination polymers, Ln(4)(mu(3)-OH)(2)Cu(6)I(5)(IN)(8)(OAc)(3) (Ln = Nd (1), Pr (2); HIN = isonicotinic acid, HOAc = acetic acid), have been synthesized under hydrothermal conditions and characterized by elemental, infrared, and thermogravimetric analyses and single-crystal X-ray diffraction. Both compounds are isostructural and crystallize in the monoclinic system, space group P2(1)/c. Both polymers are constructed from 2D lanthanide-cluster polymers based on the {Ln(16)} wheel-cluster and 1D copper-cluster polymers based on the {Cu(6)I(5)} cluster, which represent the first examples of 3D coordination frameworks created by using a combination of two different types of metal-cluster polymer units, namely, a high-nuclearity lanthanide-cluster polymer and a transition-metal-cluster polymer.     

含吡啶环的芳香醚-噁二唑类化合物的合成及其光谱研究

为开发新的高强度的有机电致发光材料, 用含烷氧基的取代苯甲酸(2)与2,6-吡啶二甲酰肼(3)在POCl3作用下, “一锅煮”法合成6个结构对称的含吡啶环的芳香醚-噁二唑4a～4f. 通过MS, IR, 1H NMR, 元素分析等手段对其结构进行了表征. 化合物的荧光性能测定结果显示此类化合物具有良好的荧光性, 其荧光发射波长均在347～507 nm范围内, 最大荧光发射波长在384 nm附近处, 且荧光强度较强. 在芳环上引入5-Br基团(4e, 4f), 化合物的荧光发射波长发生红移, 荧光强度有所减弱. 以硫酸奎宁作参比, 测定6个目标产物的荧光量子产率, 5-Br基团的引入对荧光量子产率没有明显影响. 同时讨论了代表性产物4a在不同溶剂中最大荧光激发波长处的荧光量子产率, 发现溶剂极性对该类化合物的荧光量子产率基本没有影响.     

Mild, quasireverse emulsion route to submicrometer lithium niobate hollow spheres

A water/ethylene glycol (H2O/EG) system has been designed to synthesize lithium niobate (LiNbO3) powders by a mild, one-step quasireverse emulsion method. A morphology transformation from initial nuclei to flowerlike structures and then to hollow spheres is confirmed by the time-dependent experiment. The as-obtained LiNbO3 hollow spheres are formed via Ostwald ripening under solvothermal conditions, and their absorption edge in UV/vis diffuse reflectance spectra can be effectively tuned by the current morphology control strategies. This facile, efficient, and economic work provides a new route to simply and mildly synthesize hollow LiNbO3 particles and is a good initiation in the morphology control study of LiNbO3 powders.     

A two-dimensional octacyanomolybdate(V)-based ferrimagnet: {[Mn(II)(DMF)4]3[Mo(V)(CN)8]2}n

Treatment of [HNBu3]3[Mo(V)(CN)8] with manganese(II) p-toluenesulfonate in N,N'-dimethylformamide (DMF) affords {[Mn(II)(DMF)4]3[Mo(V)(CN)8]2}n (1) as a two-dimensional network. The structure of 1 consists of [cis-Mn(II)(DMF)4(mu-NC)2]2+ and [trans-Mn(II)(DMF)4(mu-NC)2]2+ units that are linked via cyanides to three-connected [Mo(V)(CN)5(mu-CN)3]3- centers in a 4:2:6 ratio, forming 12-membered rings. Magnetic measurements indicate that 1 is a ferrimagnet (TN = 8 K) that exhibits frequency-dependent behavior in chi". Heating of 1 affords an additional magnetic phase (TN = 21 K) that is absent of linkage isomerism.     

Sex-related differences in vocal responses to pitch feedback perturbations during sustained vocalization

The present study assessed the effect of sex on voice fundamental frequency (F(0)) responses to pitch feedback perturbations during sustained vocalization. Sixty-four native-Mandarin speakers heard their voice pitch feedback shifted at ± 50, ± 100, or ± 200 cents for 200 ms, five times during each vocalization. The results showed that, as compared to female speakers, male speakers produced significantly larger but slower vocal responses to the pitch-shifted stimuli. These findings reveal a modulation of vocal response as a function of sex, and suggest that there may be a differential processing of vocal pitch feedback perturbations between men and women.     

Research progress in degradation mechanism of silicon anode materials for lithium-ion batteries

硅负极材料由于具有非常高的理论比容量,使之成为锂离子电池极具前景的负极替代材料,然而,硅负极材料在充放电过程中会发生非常大的体积变形,这会引起活性材料的破坏失效,严重影响其电化学循环性能,成为制约其在锂离子电池领域广泛应用的最大瓶颈,本文介绍了硅负极材料的不同结构形态及其在充放电过程中电化学性能的退化机理,并综述了充放电过程中的力学性能演化、相关理论分析、数值模拟计算等方面的最新国际研究进展,展望了硅负极材料力学失效方面的研究重点,     

胶体离子超级电容器的比容量评价

胶体离子超级电容器作为一种新型的超级电容器,其同时具有能量密度和功率密度高的独特优势。 目前已经发展了包括多种过渡金属阳离子和稀土阳离子,例如Mn²⁺、Fe²⁺、Co²⁺、Ni²⁺、Cu²⁺、Sn²⁺、Sn⁴⁺、La³⁺、Ce³⁺、Er³⁺和Yb³⁺的胶体离子超级电容器体系。 在电化学反应中,识别出电活性物质的存在形式对研究电极反应机理和提高比容量具有重要价值。 本文主要通过对电活性物质比容量的探讨,理解这种新型胶体离子超级电容器的电化学储能机理。 评述了胶体离子超级电容器的比容量核算方式,提出了以阳离子为标准核算比容量的原因,并与传统超级电容器的核算方式进行了比较,表明胶体离子超级电容器在提高能量密度方面具有潜在优势,有望突破现有电化学储能设备的技术瓶颈,实现下一代高能量储能器件的开发。