Internalization and Accumulation in Dendritic Cells of a Small pH‐Activatable Glycomimetic Fluorescent Probe as Revealed by Spectral Detection

DC‐SIGN, an antigen‐uptake receptor in dendritic cells (DCs), has a clear role in the immune response but, conversely, can also facilitate infection by providing entry of pathogens into DCs. The key action in both processes is internalization into acidic endosomes and lysosomes. Molecular probes that bind to DC‐SIGN could thus provide a useful tool to study internalization and constitute potential antagonists against pathogens. So far, only large molecules have been used to directly observe DC‐SIGN‐mediated internalization into DCs by fluorescence visualization. We designed and synthesized an appropriate small glycomimetic probe. Two particular properties of the probe were exploited: activation in a low‐pH environment and an aggregation‐induced spectral shift. Our results indicate that small glycomimetic molecules could compete with antigen/pathogen for binding not only outside but also inside the DC, thus preventing the harmful action of pathogens that are able to intrude into DCs, for example, HIV‐1.     

超支化季铵盐诱导制备树枝状纳米纤维膜及其性能

为开发具有高效过滤性能的膜材料,以超支化季铵盐(HBP-HTC)为枝化促进剂,利用静电纺丝技术一步法制备了聚偏氟乙烯(PVDF)树枝状纳米纤维膜,探讨了纺丝工艺对纤维膜成形结构的影响,分析了树枝状纳米纤维膜的力学性能及其空气过滤性能。结果表明：由于HBP-HTC表面丰富的季铵基团具有对电荷的稳定富集作用,可获得比用小分子季铵盐制成膜更多的树枝状纳米纤维结构,当PVDF质量分数为12%,季铵基团添加量为0.10 mol/L,纺丝电压为25 kV时,制得的纤维膜树枝状覆盖率高达78.32%,且具有较好的力学性能;所制备的纳米纤维膜厚度为40μm时,其过滤效率高达99.995%,而压降为122.4 Pa。     

面向入侵检测的集成人工免疫系统

结合入侵检测的实际需求,提出了一种集成人工免疫系统(IAIS)。该系统结合了树突状细胞算法(DCA)和否定选择算法(NSA),DCA用于检测行为特征,NSA用于检测结构特征。通过KDD99数据集实验对该系统进行验证,并与其他方法进行了比较。实验结果表明,IAIS检测性能与经典分类算法相当。IAIS具有不依赖明确标识的数据来训练检测器,可结合行为特征和结构特征进行实时入侵检测的特点。     

Monolayer MoS2 Dendrites on a Symmetry‐Disparate SrTiO3 (001) Substrate: Formation Mechanism and Interface Interaction

Dendritic patterns generated in non‐equilibrium growth processes are prevalent in nature while their formation mechanisms are far from fully understood. Here, we report a coverage‐dependent fractal degree evolution of monolayer 2H‐MoS₂ dendrites synthesized on a symmetry‐disparate substrate of SrTiO₃ (001). Surprisingly, various characterizations have revealed that the monolayer dendrites featured with orthogonal backbones are single crystalline, possessing both peculiar adlayer‐substrate interaction and abnormal indirect bandgap on SrTiO₃ (001). Further theoretical calculations indicate that a prominent diffusion anisotropy of monomer precursors, combined with the disparate adlayer‐substrate symmetry, determine the diffusion‐limited aggregation of MoS₂ towards dendritic shapes. This work provides brand‐new insights in the morphological engineering of two‐dimensional atomic crystals, and contributes greatly to an in‐depth understanding of the detailed dynamics in non‐equilibrium crystal growth.     

元胞自动机法模拟Al-Cu单相合金凝固组织

改进模拟枝晶生长常用的二维元胞自动机模型,根据Al-Cu二元合金相图,拟合出固液分配系数和液相线斜率随温度变化的曲线方程,并将其耦合入改进的模型中。应用该模型模拟出金属凝固过程中单个、多个枝晶的生长形貌和溶质浓度分布,将模拟结果与固液分配系数和液相线斜率恒定时得到的结果进行对比分析。结果表明,改进后的模型实现了枝晶生长过程中固液相溶质浓度的分离,耦合曲线方程后模拟得到的溶质浓度分布更加均匀平滑,更符合凝固基本理论。     

Lattice Boltzmann方法在枝晶生长模拟中的应用

将模拟流场和浓度场的Lattice Boltzmann方法(LBM)和一个模拟枝晶生长的改进cellular automaton(MCA)模型相耦合,模拟了合金凝固过程中单枝晶在纯扩散和存在对流两种条件下的生长行为.结果表明:在纯扩散条件下,枝晶呈现对称生长形貌;但存在对流时,枝晶的生长在上游方向得到促进,而在下游方向受到抑制,形成了非对称的枝晶生长形貌.模拟的纯扩散和对流枝晶形貌与前期的MCA-传输模型的模拟结果吻合较好.     

A Trip to Oz and a Peak Behind the Curtain of Magnesium Batteries

The introduction of the Li‐ion battery has revolutionized the electronics industry due to its high energy density. Magnesium batteries may have the potential to exceed the energy densities of Li‐ion batteries. Herein, the major advancements in magnesium electrochemistry and the challenges that must be overcome to realize a practical magnesium battery are discussed. So too are the controversial realities of current magnesium battery research and their implications.     

Phase field modeling of dendritic coarsening during isothermal solidification

Dendritic coarsening in Al-2mol%Si alloy during isothermal solidification at 880K was investigated by phase field modeling. Three coarsening mechanisms operate in the alloy: (a) melting of small dendrite arms; (b) coalescence of dendrites near the tips leading to the entrapment of liquid droplets; (c) smoothing of dendrites. Dendrite melting is found to be dominant in the stage of dendritic growth, whereas coalescence of dendrites and smoothing of dendrites are dominant during isothermal holding. The simulated results provide a better understanding of dendrite coarsening during isothermal solidification.     

强制性枝晶的侧向分枝

强制性枝晶的侧向分枝的产生和粗化机制是凝固理论尚未解决的基础问题之一。本文首次报告了采用透明晶体模型合金 SCN-4wt%Ace.,实时实地观测的实验结果,真实地描述了观察到的强制性枝晶侧向分枝的产生和侧向扰动发展的非稳态过程,并提出枝晶分枝的比例定律。实验结果和理论分析表明枝晶侧臂的粗化是扩散动力学效应,界面曲率效应和晶体学各向异性效应耦合作用的结果。本文所报告的规律可以用于解释传统凝固和快速凝固过程的组织形成。