大数据时代下的化学经验2.0：基于键能的大规模反应途径预测

报道了一个基于键能数据预测反应途径的可编程算法．运用该算法,成功预测了F₂+CH₃Cl气相反应的最优产物(CF₄)和对应的反应途径．提供了一个启示性的化学经验2.0 的例子,并可能开启大数据时代下的大规模反应途径预测的大门．     

藤黄酸诱导肺癌细胞H1975凋亡的机制研究

目的 研究藤黄酸（GA）诱导人肺癌细胞H1975凋亡的分子机制,探讨氧自由基（ROS）和JNK信号通路在GA杀伤 肺癌细胞中的作用。方法 以人肺癌细胞H1975为研究对象,MTT法测定GA抑制细胞增殖的作用,Annexin V/PI 双染法测定细胞凋亡率,DCFH-DA 法测定ROS 含量,JC-1探针染色分析线粒体膜电位（MMP）,Western blot检测JNK 信号通路的激活和线粒体凋亡途径相关蛋白表达的变化。结果 GA 呈剂量依赖性抑制H1975细胞的增殖,各实验组细胞存活率与空白对照组比较,均有统计学差异（P＜0.05 或0.01）。1、2.5 和5滋mol/L GA 作用24h 后,细胞凋亡率分别为25.2%、51.8%和75.1%,剪切型凋亡相关蛋白cleaved caspase-9、cleaved caspase-3 和cleaved PARP 的表达随GA 浓度增高而显著增加,与空白对照组比较,均有统计学差异（P＜0.05或0.01）。GA 作用2h 后H1975细胞ROS 含量显著升高,磷酸化JNK（p-JNK）表达上调（P＜0.05或0.01）。GA 作用16h后各实验组细胞MMP 均明显降低（均P＜0.05）。GA 作用24h后实验组细胞线粒体凋亡途径相关蛋白Bax、Bak、Bik表达增加,而抗凋亡蛋白Bcl-2表达与空白对照组相比明显下降（P＜0.05 或0.01）。结论 GA 具有诱导H1975 细胞凋亡的作用,其可能机制是上调细胞内ROS含量,激活JNK 信号通路,进而引起MMP 降低和线粒体凋亡途径激活。     

Theoretical kinetic study on the decomposition of 1,5‐diaminotetrazole

1,5‐Daminotetrazole (DAT) is of much interest because of the practical significance and the diversity of characteristics. The study on the decomposition pathway and the kinetics of DAT has been performed based on the quantum chemistry theory. The minimum energy path (MEP) calculation has shown that NH₂N₃ and NH₂CN are the initially detected products of DAT. And the structures of reactant, products and transition state were optimized with MP2 methods using 6‐311G** basis sets, and the energies were refined using CCSD(T)/6‐311G** levels of theory. The calculated rate constants were obtained using the conventional transition‐state theory (TST) and the canonical variational transition‐state theory (CVT) methods. The calculation results indicated that the energy barrier of decomposition reaction is 47.98 kcal mol^?1 and the variational effect is small. In addition, the rate constants and the Arrhenius experience formula of DAT decomposition have been obtained between 200 and 2500 K temperature regions. The fitted three‐parameter expressions calculated using the TST and CVT methods are (TST) and (CVT). This work may provide the theoretical support for further experimental synthesis and testing. Copyright © 2015 John Wiley & Sons, Ltd.     

Fourier analysis of scratches generated on m‐GaN substrates during polishing

Generation of scratches on surface of m‐plane GaN substrates due to polishing was studied by atomic force microscopy (AFM). For epi‐ready substrates AFM images confirm a flat surface with the atomic step roughness while a lot of scratches are visible in AFM images for partially polished GaN substrates. The Fourier analysis of AFM images show that scratches propagate easier along {c‐plane} and {a‐plane} directions on m‐plane GaN surface. This observation is an evidence of anisotropy of mechanical properties of GaN crystals in the micro‐scale. This anisotropy is directly correlated with the symmetry and atomic arrangement of m‐plane GaN.     

A Multivalent Ligand for the Mannose‐6‐Phosphate Receptor for Endolysosomal Targeting of an Activity‐Based Probe

The ubiquitously expressed mannose‐6‐phosphate receptors (MPRs) are a promising class of receptors for targeted compound delivery into the endolysosomal compartments of a variety of cell types. The development of a synthetic, multivalent, mannose‐6‐phosphate (M6P) glycopeptide‐based MPR ligand is described. The conjugation of this ligand to fluorescent DCG‐04, an activity‐based probe for cysteine cathepsins, enabled fluorescent readout of its receptor‐targeting properties. The resulting M6P‐cluster–BODIPY–DCG‐04 probe was shown to efficiently label cathepsins in cell lysates as well as in live cells. Furthermore, the introduction of the 6‐O‐phosphates leads to a completely altered uptake profile in COS and dendritic cells compared to a mannose‐containing ligand. Competition with mannose‐6‐phosphate abolished all uptake of the probe in COS cells, and we conclude that the mannose‐6‐phosphate cluster targets the MPR and ensures the targeted delivery of cargo bound to the cluster into the endolysosomal pathway.     

浙江新高考化学加试题难度研究*

在对已有试题难度量化工具进行改进的基础上,建构了化学加试题难度评估工具。对2015年至2019年国家新高考实验区浙江省的8次化学选考加试题的难度进行了量化评价。结果表明,8次化学加试题整卷难度变化较大,但同一学年、有相同学生可能参与的2次化学选考的整体难度相近;加试题能力特征和难度差异明显,“有机化学基础”加试题(第32题)难度相对稳定,而第30题(化学反应原理)与第31题(实验化学)加试题难度却表现出一定的波动性。在对8次化学加试题的难度及相关因素进行分析的基础之上,也对如何提高加试题的编制质量,提出了可行性建议。     

Impact of Positional Isomerism on Pathway Complexity in Aqueous Media

Pathway complexity has become an important topic in recent years due to its relevance in the optimization of molecular assembly processes, which typically require precise sample preparation protocols. Alternatively, competing aggregation pathways can be controlled by molecular design, which primarily rely on geometrical changes of the building blocks. However, understanding how to control pathway complexity by molecular design remains elusive and new approaches are needed. Herein, we exploit positional isomerism as a new molecular design strategy for pathway control in aqueous self‐assembly. We compare the self‐assembly of two carboxyl‐functionalized amphiphilic BODIPY dyes that solely differ in the relative position of functional groups. Placement of the carboxyl group at the 2‐position enables efficient pairwise H‐bonding interactions into a single thermodynamic species, whereas meso‐substitution induces pathway complexity due to competing hydrophobic and hydrogen bonding interactions. Our results show the importance of positional engineering for pathway control in aqueous self‐assembly.     

Living Supramolecular Polymerization of an Aza‐BODIPY Dye Controlled by a Hydrogen‐Bond‐Accepting Triazole Unit Introduced by Click Chemistry

An aza‐BODIPY dye 1 bearing two hydrophobic fan‐shaped tridodecyloxybenzamide pendants through 1,2,3‐triazole linkages was synthesized by a click reaction and characterized. ¹H NMR studies indicated that dye 1 exhibited variable conformations through intramolecular H‐bonding interaction, which is beneficial for the polymorphism of aggregation. The thermodynamic, structural, and kinetic aspect of the supramolecular polymerization of dye 1 was investigated by UV/Vis absorption spectroscopy, IR spectroscopy, AFM, TEM, and SEM. Biphasic aggregation pathways of dye 1 , leads to the formation of off‐pathway, metastable Agg. I and thermodynamically stable Agg. II with distinct H‐aggregation spectra and nanoscale morphology. The living manner of the supramolecular polymerization of dye 1 was demonstrated in seeded polymerization experiments with temperature‐modulated successive cooling–heating cycles.     

Prediction of interaction between small molecule and enzyme using AdaBoost

The knowledge of whether one enzyme can interact with a small molecule is essential for understanding the molecular and cellular functions of organisms. In this paper, we introduce a classifier to predict the small molecule– enzyme interaction, i.e., whether they can interact with each other. Small molecules are represented by their chemical functional groups, and enzymes are represented by their biochemical and physicochemical properties, resulting in a total of 160 features. These features are input into the AdaBoost classifier, which is known to have good generalization ability to predict interaction. As a result, the overall prediction accuracy, tested by tenfold cross-validation and independent sets, is 81.76% and 83.35%, respectively, suggesting that this strategy is effective. In this research, we typically choose interactions between small molecules and enzymes involved in metabolism to ultimately improve further understanding of metabolic pathways. An online predictor developed by this research is available at . Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.