Effect of doping cobalt on the micro-morphology and electrochemical properties of birnessite MnO2

Birnessite-type MnO₂ nanoparticles are synthesized by mixing KMnO₄ solution directly with ethylene glycol under ambient conditions. When cobalt exists in the solution, the micro-morphology of the products transforms from conglomeration to dispersive state. The result of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) shows that the product is constructed with nanosphere in sizes of ca. 40 nm. These nanospheres are twisted by nanorods clusters. X-ray diffraction (XRD) pattern shows that the products are birnessite-type. The electrochemical properties of the prepared materials are studied using cyclic voltammetry (CV) and galvanostatic charge–discharge test in aqueous electrolyte. The product shows a very high specific capacity of 326.4 F g⁻¹. These results indicate that cobalt has great effects on the micro-morphology and electrochemical properties of manganese dioxide.     

Secreted HSP90α-LRP1 Signaling Promotes Tumor Metastasis and Chemoresistance in Pancreatic Cancer

The extracellular heat shock protein 90α (eHSP90α) has been reported to promote cancer cell motility. However, whether pancreatic cancer (PC) cells expressed membrane-bound or secreted HSP90α, as well as its underlying mechanism for PC progression, were still unclear. Our study demonstrated that the amounts of secreted HSP90α proteins were discrepant in multiple PC cells. In addition, highly invasive Capan-2 cells have a higher level of secreted HSP90α compared with those of less invasive PL45 cells. The conditioned medium of Capan-2 cells or recombinant HSP90α treatment stimulated the migration and invasion of PC cells, which could be prevented with a neutralizing anti-HSP90α antibody. Furthermore, secreted HSP90α promoted elements of epithelial–mesenchymal transition in PL45 cells, including increases in vimentin and Snail expressions, decreases in E-cadherin expression, and changes in cell shape towards a mesenchymal phenotype, but these phenomena were reversed by the anti-HSP90α antibody in Capan-2 cells. In addition, high levels of low-density lipoprotein receptor-related protein 1 (LRP1) were associated with worsened patient survival in pancreatic adenocarcinoma. We demonstrated LRP1 as a receptor of eHSP90α for its stimulatory role in metastasis, by activating the AKT pathway. In addition, silencing LRP1 enhanced the chemosensitivity to gemcitabine and doxorubicin in Capan-2 cells. Therefore, our study indicated that blocking secreted HSP90α underlies an aspect of metastasis and chemoresistance in PC.     

人工智能技术课程实践教学改革

根据人工智能技术课程的教学情况,从教学内容、教学方法、教学案例、考核方式、培养实践能力五个方面探讨教学改革.提出在不断更新教学内容和"课堂讲授-课下辅导"模式的基础上,加强网络资源的利用,增加贯穿整个教学过程的分组报告,设计出提高创新能力的教学案例,开展具有多元考核方式以及循序渐进的动态实验设置模式的实践教学改革,以有...     

异相膜NIMTE在空气能量回收装置中使用效果试验研究

通过对国产纸膜和日本滤纸膜材料的分析研究,研制出NIMTE异相膜,并在空气能量回收装置使用过程中对风压、空气流量、热流方向与热交换效率、回收能量、能效及安全性的关系进行分析,设计出能够更好发挥异相膜使用效果的传热膜机芯,有效提高空气能量回收装置的综合性能。     

Two-dimensional MX Dirac materials and quantum spin Hall insulators with tunable electronic and topological properties

We propose a novel class of two-dimensional(2D)Dirac materials in the MX family(M=Be,Mg,Zn and Cd,X=Cl,Br and I),which exhibit graphene-like band structures with linearly-dispersing Dirac-cone states over large energy scales(0.8–1.8 eV)and ultra-high Fermi velocities comparable to graphene.Spin-orbit coupling opens sizable topological band gaps so that these compounds can be effectively classified as quantum spin Hall insulators.The electronic and topological properties are found to be highly tunable and amenable to modulation via anion-layer substitution and vertical electric field.Electronic structures of several members of the family are shown to host a Van-Hove singularity(VHS)close to the energy of the Dirac node.The enhanced density-of-states associated with these VHSs could provide a mechanism for inducing topological superconductivity.The presence of sizable band gaps,ultra-high carrier mobilities,and small effective masses makes the MX family promising for electronics and spintronics applications.     

低临界胶束浓度PEGMA-b-PCL的制备及其 药物缓释性能

以ε-己内酯（ε-CL）为疏水链段,聚乙二醇甲醚甲基丙烯酸酯（PEGMA）为亲水链段,4-氰基-4-[(十二烷基硫基硫羰基)硫基]戊酸（CDPA）为可逆加成-断裂链转移（RAFT）试剂,在以甲苯为溶剂、N2氛围、80 ℃、反应24 h的条件下,通过RAFT聚合法制备了两嵌段聚合物PEGMA-b-PCL。将其自组装为胶束用作纳米药物载体,并以姜黄素（Cur）为胶束负载药物。考察了两嵌段聚合物结构、分子量及分布,表征了胶束载体粒径、形貌,测试了胶束载体的载药和释药性能。结果表明,不同嵌段聚合物相对分子质量范围为478~7318,此类聚合物具有较低的临界胶束浓度（CMC）,在常规条件下（pH=7.4）其范围为0.920~1.600 μg/mL。胶束载体粒径范围为:68.34~186.30 nm。当n(CDPA)∶n(ε-CL)=1∶200时,胶束载药量和包封率最高,可达12.05%和75.26%。在不同pH值环境下,药物缓释性能可达15 d,其中pH=5.0时释药量可达35.38%。     

Biomimetic Modification of Water-Borne Polymer Coating with Carnauba Wax for Controlled Release of Urea

Benefitting from the special structure of the leaf cuticle layer, plants have natural hydrophobicity and anti-fouling abilities. Inspired by the leaf surface structure, a biomimetic modification strategy was raised to improve the surface hydrophobicity of polyacrylate coating for controlled release fertilizer. Double-layer (polyacrylate and carnauba wax) coated fertilizer was obtained after biomimetic modification. The quality of controlled release fertilizer modified with the carnauba wax was greatly enhanced, and the coating material was effectively saved. The surface appearance of polyacrylate-coated fertilizer was improved for the surface blemish was repaired by the loaded carnauba wax. The characterizations by Fourier transform infrared spectroscopy indicated that the hydrogen bonds were formed between the water-based polyacrylate membrane and the carnauba wax layers. By optimizing the content of polyacrylate and carnauba wax, the release duration of the fertilizer was effectively prolonged, which was improved from 1 month to more than 2 months after the biomimetic modification. Therefore, biological wax as an environmentally-friendly natural material that has showed a broad potential in the application of coated controlled release fertilizer.     

我国混凝土空心砌块节能建筑案例分析

通过我国混凝土空心砌块节能建筑案例分析,提出外保温、内保温、夹芯保温各有优缺点,应因地制宜,依据建筑功能要求采取适合的保温方式,并根据多年的研究和应用实践经验,提出了我国不同气候区域混凝土空心砌块节能建筑的外墙构造设计方案。