Antifungal activity of phenolic monoterpenes and structure-related compounds against plant pathogenic fungi

The aim of this work is to explore the possibility of using the phenolic monoterpenes (PMs) as leading compounds with antifungal activity against plant disease. The in vitro antifungal activities of carvacrol and thymol against seven kinds of plant pathogenic fungi were evaluated on mycelium growth rate method, and the results showed that carvacrol and thymol exhibited broad spectrum antifungal activity. Structure requirement for the antifungal activity of PMs was also investigated. The preliminary conclusion was that phenolic hydroxyl and monoterpene were basic structures for the antifungal activity of PMs, and the position of phenolic hydroxyl showed less effect. Ester derivatives of carvacrol and thymol were more effective than carvacrol and thymol against plant pathogenic fungi. We suggested that carvacrol, thymol and their ester derivatives could potentially be used as new fungicide leading compounds.     

Discovery of a Prenylated Flavonol Derivative as a Pin1 Inhibitor to Suppress Hepatocellular Carcinoma by Modulating MicroRNA Biogenesis

Peptidyl‐prolyl cis‐trans isomerase Pin1 plays a crucial role in the development of human cancers. Recently, we have disclosed that Pin1 regulates the biogenesis of miRNA, which is aberrantly expressed in HCC and promotes HCC progression, indicating the therapeutic role of Pin1 in HCC therapy. Here, 7‐(benzyloxy)‐3,5‐dihydroxy‐2‐(4‐methoxyphenyl)‐8‐(3‐methylbut‐2‐en‐1‐yl)‐4H‐chromen‐4‐one ( AF‐39 ) was identified as a novel Pin1 inhibitor. Biochemical tests indicate that AF‐39 potently inhibits Pin1 activity with an IC₅₀ values of 1.008 μm , and also displays high selectivity for Pin1 among peptidyl prolyl isomerases. Furthermore, AF‐39 significantly suppresses cell proliferation of HCC cells in a dose‐ and time‐dependent manner. Mechanistically, AF‐39 regulates the subcellular distribution of XPO5 and increases miRNAs biogenesis in HCC cells. This work provides a promising lead compound for HCC treatment, highlighting the therapeutic potential of miRNA‐based therapy against human cancer.     

非均匀关联径向偏振部分相干光的产生

从理论和实验两方面对非均匀关联径向偏振部分相干光的产生进行了研究.理论上,基于相位关联与相干度的联系,推导出了非均匀关联径向偏振部分相干光的2×2阶交叉谱密度矩阵及相干度分布.实验上,利用一个相位型液晶空间光调制器的不同区域,对入射的完全相干的径向偏振光的两个正交偏振分量分别加载随机相位调制,并实验测量了这种光束的相干度分布及其对光强分布的影响.实验结果验证了光束相干度的非均匀关联结构,并且通过改变随机相位的高斯调制半宽可以改变光束的相干性分布.研究表明,随着随机相位的高斯调制半宽的增加,光束中两点间的相干度逐渐减小,其光强分布由圆环状逐渐变化为类平顶的光强分布.这种非均匀关联的径向偏振部分相干光在激光微操纵和材料加工等领域具有一定的潜在应用价值.     

Bifunctional probe for Cu2+/Al3+ based on a diarylethene with a 4, 5-[bis-(5-ethylacetate-yl)-2-thienyl]-1H-imidazole unit

A new asymmetric perfluordiarylethene (1O) was synthesized using 4, 5-[bis-(5-ethylacetate-yl)-2-thienyl]-1H-imidazole as a functional group. 1O exhibited favorable reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light. Both of its open- and closed-ring isomers were found to be highly selective towards Cu²⁺ with significant absorption and color changes, which could be used as a ‘naked-eye’ colorimetric sensor for Cu²⁺ detection. Upon exposure to acid, its fluorescence dramatically enhanced by 14-fold with a color change from dark to bright cyan due to the formation of the protonated compound. Moreover, 1O showed obvious fluorescence “turn-on” signal response towards Al³⁺, and the detection limit for Al³⁺ was determined to be 4.8 × 10^?9 mol L^?1. Based on the fluorescence signals of 1O, a combinational stimuli logic circuit were designed by using the fluorescence intensity as the output signal with the inputs of lights, Al³⁺ and EDTA. Finally, 1O could be used as a biological probe for detecting intracellular Al³⁺ in a physiological environmental.     

A bifunctional probe for Al3+ and Zn2+ based on diarylethene with an ethylimidazo[2,1-b]thiazole-6-hydrazide unit

A new diarylethene with ethylimidazo[2,1-b]thiazole-6-hydrazide unit was synthesized, and its photochromic and fluorescent behaviors have been systematically investigated by the stimulation of lights and metal ions in methanol. This new diarylethene exhibited high selectivity and sensitivity toward Al³⁺ and Zn²⁺. The addition of Al³⁺ and Zn²⁺ displayed excellent colorimetric response behaviour with the concomitant color change from colorless to yellow, which could be easily observed by the naked eye. Upon addition of Al³⁺, the fluorescence intensity was enhanced by 180–fold and the emission peak of 1O–Al³⁺ blue-shifted by 15?nm accompanied with a color change from colorless to bright blue. In contrast, when stimulated with Zn²⁺, its fluorescence intensity was enhanced by 35–fold and the emission peak of 1O–Zn²⁺ red-shifted by 16?nm with an evident color change from black to bright green. The LOD for Al³⁺ and Zn²⁺ were determined to be 2.97?×?10^?9?mol?L^?1 and 5.98?×?10^?9?mol?L^?1, respectively. Moreover, a logic circuit was constructed with the fluorescence intensity as the output signal responding to the light and chemical species as the inputs.     

Spectroscopic studies of a BINAM-based sensor: Highly selective fluorescent recognition of lysine in water solution through a nucleophilic substitution reaction

A BINAM-based compound (R)-1 is found to show significant fluorescence enhancement in the presence of Lys in aqueous solution (1%DMF). This probe achieves highly selective fluorescent recognition of Lys even in the presence of other natural amino acids. It can be used as a sensitive as well as selective fluorescent probe for Lys. The mechanism for the interaction of (R)-1 with Lys was studied by NMR and HRMS.     

Reactions of 2‐Aryl‐1,3‐Dithianes and [1.1.1]Propellane

Bicyclo[1.1.1]pentanes (BCPs) have sparked the interest of medicinal chemists due to their recent discovery as bioisosteres of aromatic rings. To study the biological activity of this relatively new class of bioisosteres, reliable methods to incorporate BCPs into target molecules are in high demand, as reflected by a flurry of methods for BCP synthesis in recent years. In this work, we disclose a general method for the synthesis of BCP‐containing dithianes which, upon deprotection, provide access to BCP analogues of medicinally abundant diarylketones. A broad scope of 2‐aryl‐1,3‐dithianes, including several heterocyclic derivatives, react with [1.1.1]propellane to afford 26 new derivatives in good to excellent yields. Further transformation of the dithiane portion into a variety of functional groups demonstrates the robustness of the products. A computational study indicates that the reaction of 2‐aryl‐1,3‐dithianes and [1.1.1]propellane proceeds via a two‐electron pathway.     

Influence of water on HFO-1234yf oxidation pyrolysis via ReaxFF molecular dynamics simulation

ABSTRACT

The effect of water molecules on HFO-1234yf oxidation pyrolysis was investigated by ReaxFF-molecular dynamics simulation from 1900 to 4200?K. The initial pyrolysis of HFO-1234yf starts around 2500?K and the water molecules participate in chemical reactions at 2800?K when the reactants pyrolysis reached the highest reaction rate. The primary products including HF, COF₂ and CO₂ are observed at 2600, 2700 and 2900?K, respectively. The influence of water molecules on products is mainly reflected in the promotion activity on the conversion from COF₂ to CO₂ and the generation of HF molecules. Four formation pathways are observed and calculated to further elucidate the procedure of pyrolysis. The main conversion process from H₂O to HF is the ?F?+?H₂O?=?HF+?OH reaction, and the paths from H₂O to ?OH radical and COF₂ to ?CFO radical which are promoted by ?F and ?H radical, respectively, have relatively low energy barriers of 10.44 and 40.29?kJ/mol, and both reaction processes released HF molecules.     

Structure,Electronic, and Mechanical Properties of Three Fully Hydrogenation h-BN:Theoretical Investigations

The structural, electronic, elastic, mechanical properties and stress-strain relationship of chair, boat, and stirrup conformers of fully hydrogenated h-BN(fh-BN) are investigated in this work using the Perdew-Burke-Ernzerhof(PBE) function in the frame of density functional theory. The achieved results for the lattice parameters and band gaps of three conformers in this research are in good accordance with other theoretical results. The band structures of three conformers show that the chair, boat, and stirrup are direct band gap with a band gaps of(3.12, 4.95, and4.95 e V), respectively. To regulate the band structures of fh-BN, we employ a hybrid functional of Heyd-ScuseriaErnzerhof(HSE06) calculations and the band gaps are 3.84(chair), 6.12(boat), and 6.18 e V(stirrup), respectively.The boat and stirrup fh-BN exhibits varying degrees of mechanical anisotropic properties with respect to the Young's modulus and Poisson's ratio, while the chair fh-BN exhibits the mechanical isotropic properties. Furthermore, tensile strains are applied in the armchair and zigzag directions related to tensile deformation of zigzag and armchair nanotubes,respectively. We find that the ultimate strains in zigzag and armchair deformations in stirrup conformer are 0.34 and0.25, respectively, larger than the strains of zigzag(0.29) and armchair(0.18) deformations in h-BN although h-BN can surstain a surface tension up to the maximum stresses higher than those of three conformers of fh-BN. Furthermore, the band gap energies in three conformers can be modulated effectively with the biaxial tensile strain.     

窄线宽脉冲光纤激光的自相位调制预补偿研究

自相位调制(SPM)效应会展宽窄线宽脉冲光纤激光的光谱宽度,降低其相干性.通过相位调制对SPM引起的非线性相移进行预补偿,能够使脉冲激光在光纤中进行放大和传输后保持种子激光的光谱特性.基于三波耦合方程开展数值仿真,研究了在对SPM进行"欠补偿","完全补偿"和"过补偿"的情况下,SPM预补偿对受激布里渊散射阈值和激光光谱特性的影响.开展了SPM预补偿实验研究,将脉冲激光的光谱宽度从1.4 GHz压缩到120 MHz.研究内容可以为窄线宽脉冲光纤激光系统的设计搭建提供参考.