Cell uptake and oral absorption of titanium dioxide nanoparticles

Large efforts are invested on the development of in vitro tests to evaluate nanomaterial (NM) toxicity. In order to assess the relevance of the adverse effects identified in in vitro toxicity tests a thorough understanding of the biokinetics of NMs is critical. We used different in vitro and in vivo test methods to evaluate cell uptake and oral absorption of titanium dioxide nanoparticles (TiO₂ NPs). These NPs were readily uptaken by A549 cells (carcinomic human alveolar basal epithelial cells) in vitro. Such rapid uptake contrasted with a very low oral absorption in a differentiated Caco-2 monolayer system (human epithelial colorectal adenocarcinoma cells) and after oral gavage administration to rats. In this oral study, no significant increase in the levels of titanium was recorded by ICP-MS in any of the tissues evaluated (including among other: small intestine, Peyer's patches, mesenteric lymph nodes, liver, and spleen). No NPs were observed by TEM in sections of the small intestine, except for several particles in the cytoplasm of a cell from a Peyer's Patch area. The observation of NPs in Peyer's Patch suggests that the Caco-2 monolayer system is likely to underestimate the potential for oral absorption of NPs and that the model could be improved by including M-cells in co-culture.     

无水银二氧化碳结合力测定器的研制

本文介绍了测定二氧化碳结合力的一种新型仪器一快速无水银二氧化碳结合力测定器。该测定器安全无污染，测定结果准确，具有一定的科学创新性和实用性。     

基于三维打印的钙化层重建生物活性支架制备及其性能研究

目的初步构建基于软骨钙化层损伤重建的有机—无机复合组织工程支架,探究掺镁硅灰石含量与支架抗压性能之间的关系。方法利用质量分数分别为1%、3%、5%的高生物活性钙镁硅酸盐超细颗粒复合Ⅰ型胶原—透明质酸钠进行三维打印,经海藻酸钠—氯化钙气雾交联成型,电镜下观察表面孔隙、孔径、无机相分布,万能材料试验机测试抗压性能,并计算支架孔隙率。结果支架表面平均孔径(212.3±34.2)μm,平均孔隙率(48.3±5.9)%,不同质量分数的高生物活性钙镁硅酸盐超细颗粒复合Ⅰ型胶原—透明质酸钠支架压缩模量差异无统计学意义( P>0.05),平均压缩模量(7.2±1.2)MPa,介于软骨和软骨下骨之间。 结论利用三维打印技术成功构建出多孔钙化层仿生重建支架,可为今后研制多层次复合支架治疗骨—软骨损伤奠定基础。     

Medical gases

Understanding the complex process of production, storage and delivery of medical gases is vitally important to ensure safe and efficient practice by anaesthetists. This article discusses the medical gases commonly used in anaesthesia and intensive care and details the journey of the commonly used medical gases from production to patient delivery. It includes core knowledge for the FRCA.     

Haematic silicon in drowning

The aim of this paper was to evaluate silicon (Si) concentration in human whole ventricular blood as a further potential chemical marker in the diagnosis of drowning. We employed an acidic digestion for the extraction of soluble Si, and an alkaline digestion for the determination of total Si, including particulate matter, both arising from drowning medium. 29 suspected drowning situations, 24 in fresh water (Fw) and 5 in seawater (Sw), were examined. The difference in Si concentration between the left and right ventricular blood (Si Δ_L–R) was measured and alkaline Si Δ_L–R seems, indeed, a potentially significant complementary tool in the diagnosis of Fw drowning, because insoluble silicon fraction does not undergo hemo-dilution or hemo-concentration, and the Δ_L–R is not affected by exogenous factors. In spite of the limited number of cases investigated, a good correlation was observed between the analytical results and the macro-microscopic autoptic findings.     

广东省3个城市大气污染物二氧化氮对居民的死亡效应研究

目的 探讨广东省广州、佛山及珠海3个城市的大气污染二氧化氮（NO₂）对居民每日死亡效应的影响。方法 收集2013—2016年广州、佛山及珠海3个城市的每日大气污染物浓度、气象资料数据和居民的每日总死亡数据,对数据基本特征进行统计描述,并通过Spearman分析其相关关系,最后利用广义相加模型（GAM）分别对3个城市的NO₂日均浓度及每日总死亡数据进行分析。结果 2013—2016年广州、佛山及珠海市的大气污染物NO₂日均浓度分别为46.4、48.4、33.1 μg/m³,均符合国家二级标准（80 μg/m³）。广州市大气中NO₂日均浓度对当天、滞后1、2 d的每日总死亡人数、循环系统疾病死亡人数的影响有统计学意义（均P<0.05）,佛山市滞后1、2 d的NO₂日均浓度对居民每日总死亡人数及循环系统疾病每日死亡人数的影响有统计学意义（均P<0.05）,广州和佛山市均表现出滞后1 d时效应最大。滞后2 d的NO₂日均浓度对广州市居民的呼吸系统疾病每日死亡人数有影响（ER=1.38）。结论 大气污染物NO₂浓度的上升会引起居民死亡风险的增加,应引起重视。