Effects of vacancy structural defects on the thermal conductivity of silicon thin films

Vacancy structural defect effects on the lattice thermal conductivity of silicon thin films have been investigated with non-equilibrium molecular dynamics simulation.The lattice thermal conductivities decrease with increasing vacancy concentration at all temperatures from 300 to 700 K.Vacancy defects decrease the sample thermal conductivity,and the temperature dependence of thermal conductivity becomes less significant as the temperature increases.The molecular dynamics result is in good agreement with the theoretical analysis values obtained based on the Boltzmann equation.In addition,theoretical analysis indicates that the reduction in the lattice thermal conductivity with vacancy defects can be explained by the enhanced point-defect scattering due to lattice strain.     

可用于高功率脉冲激光的面阵CCD模式测量装置

本文介绍了一种用面阵ＣＣＤ摄像机作探测器的激光光束测量装置。整个装置包括光束衰减器、单脉冲选取及脉冲同步、光束直径匹配、ＣＣＤ摄像机、图像卡、计算机及监示器以及系统软件。软件根据激光混合模的二阶矩阵理论［１］编制，可测量高功率、高重复频率脉冲激光的空间能量分布，并可对所测结果进行模拟。由软件给出所测的光束参数，可对光束质量作出正确评价。     

A New Inductor Series-Peaking Technique for Bandwidth Enhancement of CMOS Current-Mode Circuits

This paper introduces a new inductor series-peaking technique for bandwidth enhancement of low-voltage CMOS current-mode circuits. The peaking inductor is in series with the capacitor constituting the dominant pole. It boosts the bandwidth by utilizing the resonance characteristics of LC networks. To reduce the value of the peaking inductor, a new negative current-current feedback mechanism is proposed. The employment of both inductive peaking and current feedback further increases the bandwidth. Both the inductor series-peaking and the current-current feedback do not affect the supply voltage and DC biasing conditions. Theoretical analysis and simulation results show that a significant bandwidth enhancement is achieved.     

Benzamides Substituted with Quinoline-Linked 1,2,4-Oxadiazole: Synthesis,Biological Activity and Toxicity to Zebrafish Embryo

To develop new compounds with high activity, broad spectrum and low-toxicity, 17 benzamides substituted with quinoline-linked 1,2,4-oxadiazole were designed using the splicing principle of active substructures and were synthesized. The biological activities were evaluated against 10 fungi, indicating that some of the synthetic compounds showed excellent fungicidal activities. For example, at 50 mg/L, the inhibitory activity of 13p (3-Cl-4-Cl substituted, 86.1%) against Sclerotinia sclerotiorum was superior to that of quinoxyfen (77.8%), and the inhibitory activity of 13f (3-CF₃ substituted, 77.8%) was comparable to that of quinoxyfen. The fungicidal activities of 13f and 13p to Sclerotinia sclerotiorum were better than that of quinoxyfen (14.19 mg/L), with EC₅₀ of 6.67 mg/L and 5.17 mg/L, respectively. Furthermore, the acute toxicity of 13p was 19.42 mg/L, classifying it as a low-toxic compound.     

The Intervention of Prebiotics on Depression via the Gut–Brain Axis

The imbalance of intestinal microbiota can cause the accumulation of endotoxin in the main circulation system of the human body, which has a great impact on human health. Increased work and life pressure have led to a rise in the number of people falling into depression, which has also reduced their quality of life. The gut–brain axis (GBA) is closely related to the pathological basis of depression, and intestinal microbiota can improve depressive symptoms through GBA. Previous studies have proven that prebiotics can modulate intestinal microbiota and thus participate in human health regulation. We reviewed the regulatory mechanism of intestinal microbiota on depression through GBA, and discussed the effects of prebiotics, including plant polysaccharides and polyphenols on the regulation of intestinal microbiota, providing new clues for the prevention and treatment of depression.     

Investigation of the Uptake and Transport of Two Novel Camptothecin Derivatives in Caco-2 Cell Monolayers

Irinotecan and Topotecan are two Camptothecin derivatives (CPTs) whose resistance is associated with the high expression of breast cancer resistance protein (BCRP) and P-glycoprotein (P-gp). To reverse this resistance, two novel CPTs, FL77-28 (7-(3-Fluoro-4-methylphenyl)-10,11-methylenedioxy-20(S)-CPT) and FL77-29 (7-(4-Fluoro-3-methylphenyl)-10,11-methylenedioxy-20(S)-CPT), were synthesized by our group. In this study, the anti-tumor activities of FL77-28, FL77-29, and their parent, FL118 (10,11-methylenedioxy-20(S)-CPT), were evaluated and the results showed that FL77-28 and FL77-29 had stronger anti-tumor activities than FL118. The transport and uptake of FL118, FL77-28, and FL77-29 were investigated in Caco-2 cells for the preliminary prediction of intestinal absorption. The apparent permeability coefficient from apical to basolateral (P_{app AP-BL}) values of FL77-28 and FL77-29 were (2.32 ± 0.04) × 10⁻⁶ cm/s and (2.48 ± 0.18) × 10⁻⁶ cm/s, respectively, suggesting that the compounds had moderate absorption. Since the transport property of FL77-28 was passive diffusion and the efflux ratio (ER) was less than 2, two chemical inhibitors were added to further confirm the involvement of efflux proteins. The results showed that FL77-28 was not a substrate of P-gp or BCRP, but FL77-29 was mediated by P-gp. In conclusion, FL77-28 might be a promising candidate to overcome drug resistance induced by multiple efflux proteins.     

Dynamic Variation of Amino Acid Contents and Identification of Sterols in Xinyang Mao Jian Green Tea

As important biomolecules in Camellia sinensis L., amino acids (AAs) are considered to contribute to the overall green tea sensory quality and undergo dynamic changes during growth. However, limited by analytical capacity, detailed AAs composition in different growth stages remains unclear. To address this question, we analyzed the dynamic changes of 23 AAs during leaf growth in Xinyang Mao Jian (XYMJ) green tea. Using amino acid analyzer, we demonstrated that most AAs are abundant on Pure Brightness Day and Grain Rain Day. After Grain Rain, 23 AAs decreased significantly. Further analysis shows that theanine has a high level on the day before Spring Equinox and Grain Rain, accounting for 44–61% of the total free AAs content in tea leaves. Glu, Pro, and Asp are the second most abundant AAs. Additionally, spinasterol and 22,23-dihydrospinasterol are first purified and identified in ethanol extract of XYMJ by silica gel column chromatography method. This study reveals the relationship between plucking days and the dynamic changes of AAs during the growth stage and proves the rationality of the traditional plucking days of XYMJ green tea.