Synthesis and evaluation of the SERS effect of Fe3O4–Ag Janus composite materials for separable,highly sensitive substrates

Fe₃O₄–Ag Janus composites were synthesized using a two-step solvothermal method. The optimal growth process was determined by investigating the relationship between the particle morphologies and reaction time. Magnetic and Raman spectroscopic measurements showed that the as-synthesized Janus composites have both good magnetic response and significant surface-enhanced Raman scattering (SERS) effects, as well as reproducibility. The calculated Raman enhancement factor reached an unprecedented magnitude of 10⁹ compared with the values of other Fe₃O₄–Ag compounds. Furthermore, the SERS effect was exhibited even at a concentration of probe molecules as low as 10⁻¹³ M. This demonstrates that the as-synthesized Fe₃O₄–Ag Janus composite particles have promise for application as separable, highly sensitive SERS substrates.

Fe₃O₄–Ag Janus composites were synthesized using a two-step solvothermal method.     

ZnO nanorod arrays grown on g-C3N4 micro-sheets for enhanced visible light photocatalytic H2 evolution

The designed synthesis of noble-metal-free photocatalysts with hierarchical heteroassemblies in a facile, mild and eco-friendly way becomes more and more important, because we can explore the novel properties and applications of novel heterostructures via this method. Herein we report a two-step aqueous strategy for novel hierarchical heterostructures of ZnO nanorod (NR) arrays grown on graphitic carbon nitride (g-C₃N₄). The novel g-C₃N₄/ZnO NR heterostructures that integrate g-C₃N₄ and ZnO NR via high-quality g-C₃N₄–ZnO heterojunctions have beneficial properties such as high specific surface area (SSA), open spatial architecture, good electronic conductivity, and effective charge transfer interfaces, and are promising in many related areas such as water splitting, solar cells, etc. As a noble-metal-free and visible-light-responsive photocatalytic material, a typical g-C₃N₄/ZnO NR photocatalytic system exhibits enhanced photocatalytic activity toward H₂ evolution, almost 3.5 times higher than that of pure g-C₃N₄. The superior photocatalytic property can be ascribed to the synergistic effect of the unique g-C₃N₄/ZnO NR heterostructures.

The designed synthesis of photocatalysts with hierarchical heteroassemblies in a facile, mild and eco-friendly way becomes more and more important, since we can explore the novel properties and applications of novel heterostructures via this method.     

血清半胱氨酸蛋白酶裂解细胞角蛋白18预测慢性乙型肝炎转归

目的探讨血清半胱氨酸蛋白酶裂解细胞角蛋白18(CK18)对慢性乙型肝炎肝病严重程度的预测价值。方法选取2017年3月至2018年3月府谷县人民医院收治的122例慢性乙型肝炎患者。按照METAVIR评分系统肝纤维化分期分为轻度肝纤维化组(n=69)、重度肝纤维化组(n=53);根据METAVIR评分系统肝脏炎症活动度分级分为轻度肝脏炎症组(n=76)、重度肝脏炎症组(n=46)。通过酶联免疫吸附试验测定血清CK18水平。结果轻度肝纤维化组血清CK18[167.86(89.54~274.65)U/L]水平显著低于重度肝纤维化组[231.98(132.09~564.38)U/L],差异有统计学意义(Z=12.765,P=0.002)。轻度肝脏炎症组血清CK18水平[138.23(165.34~677.46)U/L)]显著低于重度肝脏炎症组[337.43(82.87~234.15)U/L],差异有统计学意义(Z=15.917,P=0.001)。血清CK18预测慢性乙型肝炎患者严重肝脏炎症程度的预测效能更佳。结论血清CK18水平可用于预测慢性乙型肝炎重度肝脏组织炎症。     

A 2D metal–organic framework/reduced graphene oxide heterostructure for supercapacitor application

Metal organic frameworks (MOFs) with two dimensional (2D) nanosheets have attracted special attention for supercapacitor application due to their exceptional large surface area and high surface-to-volume atom ratios. However, their electrochemical performance is greatly hindered by their poor electrical conductivity. Herein, we report a 2D nanosheet nickel cobalt based MOF (NiCo-MOF)/reduced graphene oxide heterostructure as an electrode material for supercapacitors. The NiCo-MOF 2D nanosheets are in situ grown on rGO surfaces by simple room temperature precipitation. In such hybrid structure the MOF ultrathin nanosheets provide large surface area with abundant channels for fast mass transport of ions while the rGO conductive and physical support provides rapid electron transport. Thus, using the synergistic advantage of rGO and NiCo-MOF nanosheets an excellent specific capacitance of 1553 F g⁻¹ at a current density of 1 A g⁻¹ is obtained. Additionally, the as synthesized hybrid material showed excellent cycling capacity of 83.6% after 5000 cycles of charge–discharge. Interestingly, the assembled asymmetric device showed an excellent energy density of 44 W h kg⁻¹ at a power density of 3168 W kg⁻¹. The electrochemical performance obtained in this report illustrates hybridization of MOF nanosheets with carbon materials is promising for next generation supercapacitors.

In this 2D NiCo-MOF/rGO hybrid, the MOF nanosheets provide abundant active sites while the conductive rGO provide rapid electron transport.     

镍钛合金表面含银二氧化钛薄膜的水热制备与性能

采用硝酸银溶液对镍钛合金进行水热处理,表面形成了尺寸60～90 nm颗粒的薄膜,分布有约90 nm的含银颗粒。X射线衍射检测到锐钛矿型二氧化钛和单质银的弱衍射峰。X射线光电子能谱分析表明,水热处理形成的二氧化钛薄膜基本覆盖住了镍钛基体,Ag元素以金属态存在。含银二氧化钛薄膜具有较好的紫外光致亲水性。在无钙Hank’s平衡盐液中的动电位极化实验表明,水热处理试样的耐蚀性高于抛光试样,但银的掺入造成阳极极化电流的波动。抛光镍钛试样对葡萄球菌没有抑菌作用,而水热处理试样在暗环境下具有抑菌功能,周围形成了平均宽度约1．2 mm的抑菌圈。     

无线体域网体表信道模型研究进展

体表信道是无线体域网体表节点间建立有效可靠无线连接的物理基础.由于体表节点发射功率和功耗有着严格的限制,且体域网具有以人为中心的特点,使得体表信道易受到人体组织电磁特性、人体运动、应用环境和收发天线等因素的影响,极大地增加了信道模型研究的复杂性.主要针对单一路径损耗、混合路径损耗、小尺度衰落、基于场景以及适用于超宽带的5种不同体表信道模型的建立发展、数学表达和应用特点几方面,对目前无线体域网体表信道模型的研究进展作一综述.     

磁性压迫腹部大血管血流阻断系统的研制

磁性压迫腹部大血管血流阻断系统由体内磁阻断单元、体外电磁单元、非顺磁性手术器械组成。该系统在特制的手术床上预置体外电磁单元,当术中需要阻断腹主动脉或下腔静脉时,可将体内磁阻断单元直接置于拟阻断大血管的腹侧,此时体内外磁单元相吸可迅速、直接压迫拟阻断血管,关闭腹腔出血总“阀门”。该系统利用磁性材料非接触性吸力的特点,借助生物医学工程技术,能够实现腹部手术术中迅速控血,该方法直接压迫拟阻断血管,无需分离就能达到血管阻断目的。     

金砖五国药物政策比较及对我国的启示

目的:比较巴西、俄罗斯、印度、中国和南非五个金砖国家的药物政策,为进一步完善我国的基本药物制度提供借鉴.方法:采用系统评价的方法,对比研究和系统总结这些国家药物政策及部分国家实施基本药物制度的经验.结果:巴西实施基本药物制度,并开办大众药店;俄罗斯实施医药分离制度;印度德里的基本药物制度模式具有典型代表性;南非政府集中采购与配送等.这些金砖国家的药物政策各有其特点,但目的一致,即增加大众对低价、高质量药品的可获得性.结论:金砖国家药物政策改革成效显著,但各国政府在深化医药改革中依然面临着严峻的挑战,还需要根据本国国情不断地探索,同时借鉴发达国家的经验,进一步巩固与完善本国的药物政策.