Chromium(III) oxide nanoparticles induced remarkable oxidative stress and apoptosis on culture cells

Chromium(III) oxide (Cr₂O₃) is used for industrial applications such as catalysts and pigments. In the classical form, namely the fine particle, Cr₂O₃ is insoluble and chemically stable. It is classified as a low‐toxicity chromium compound. Recently, industrial application of nanoparticles (a new form composed of small particles with a diameter of ≤100 nm, in at least one dimension) has been increasing. Cellular effects induced by Cr₂O₃ nanoparticles are not known. To shed light upon this, the release of soluble chromium from Cr₂O₃ nano‐ and fine‐particles in culture medium was compared. Fine Cr₂O₃ particles were insoluble in the culture medium; on the contrary, Cr₂O₃ nanoparticles released soluble hexavalent chromium into the culture medium. Cr₂O₃ nanoparticles showed severe cytotoxicity. The effect of Cr₂O₃ nanoparticles on cell viability was higher than that of fine particles. Cr₂O₃ nanoparticles showed cytotoxicity equal to that of hexavalent chromium (K₂Cr₂O₇). Human lung carcinoma A549 cells and human keratinocyte HaCaT cells showed an increase in intracellular reactive oxygen species (ROS) level and activation of antioxidant defense systems on exposure to Cr₂O₃ nanoparticles. Exposure of Cr₂O₃ nanoparticles led to caspase‐3 activation, showing that the decrease in cell viability by exposure to Cr₂O₃ nanoparticles was caused by apoptosis. Cellular responses were stronger in the Cr₂O₃ nanoparticles‐exposed cells than in fine Cr₂O₃‐ and CrCl₃‐exposed cells. Cellular uptake of Cr₂O₃ particles were observed in nano‐ and fine‐particles. The cellular influence of the extracellular soluble trivalent chromium was lower than that of Cr₂O₃ nanoparticles. Cr₂O₃ nanoparticles showed cytotoxicity by hexavalent chromium released at outside and inside of cells. The cellular influences of Cr₂O₃ nanoparticles matched those of hexavalent chromium. In conclusion, Cr₂O₃ nanoparticles have a high cytotoxic potential. © 2011 Wiley Periodicals, Inc. Environ Toxicol 2013.     

微波消解-电感耦合等离子体质谱法测定胶囊中的铬

本文通过对胶囊进行预处理,建立了ICP-MS法测定胶囊中铬含量的检测方法。该方法检出限为0．18μg／L,精密度RSD为0．8％。该方法灵敏、准确、可靠,对控制胶囊中铬元素的含量有实际意义。     

Manganese–Cobalt Based Spinel Coatings Processed by Electrophoretic Deposition Method: The Influence of Sintering on Degradation Issues of Solid Oxide Cell Oxygen Electrodes at 750 °C

This paper seeks to examine how the Mn–Co spinel interconnect coating microstructure can influence Cr contamination in an oxygen electrode of intermediate temperature solid oxide cells, at an operating temperature of 750 °C. A Mn–Co spinel coating is processed on Crofer 22 APU substrates by electrophoretic deposition, and subsequently sintered, following both the one-step and two-step sintering, in order to obtain significantly different densification levels. The electrochemical characterization is performed on anode-supported cells with an LSCF cathode. The cells were aged prior to the electrochemical characterization in contact with the spinel-coated Crofer 22 APU at 750 °C for 250 h. Current–voltage and impedance spectra of the cells were measured after the exposure with the interconnect. Post-mortem analysis of the interconnect and the cell was carried out, in order to assess the Cr retention capability of coatings with different microstructures.     

Magnetron Sputtering vs. Electrodeposition for Hard Chrome Coatings: A Comparison of Environmental and Economic Performances

The coating of materials with specific films is widely used to improve material properties and many technologies exist to perform it. In the last few years, the replacement of wet electrodeposition processes has been continuously encouraged in the EU due to the problematic waste management linked to those processes. In this paper, magnetron sputtering is studied as an alternative to conventional electrodeposition by comparing the technologies’ environmental impacts and costs. From the study, it appears that while magnetron sputtering greatly reduces hexavalent chromium emissions over the production, it has an increased electricity consumption mostly due to its lower production capacity, thus leading to more greenhouse gas emissions. Furthermore, a short discussion on the quantification of the impact of hexavalent chromium emissions is conducted. Regarding costs, the electrodeposition process has a lower cost of investment and of consumables, but requires more work time for the different steps of the process, making the total price per functional unit roughly equal. However, the cost per functional unit strongly depends on assumptions on the required work time, for which a sensitivity study is performed. Finally, the impacts of these two competing coating processes are discussed to complete the technological comparison for the case of hard chromium deposition.     

镍铬合金烤瓷修复体拆除前后患牙龈下菌群的变化

背景：目前有关镍铬合金烤瓷修复体对龈下菌群影响的研究还较少。目的：探讨镍铬合金烤瓷修复体对龈下菌群构成比的影响。方法：选择因怀疑镍铬合金烤瓷修复体影响健康而要求拆除原修复体的烤瓷牙患者9例（患牙12颗）,于镍铬合金烤瓷烤瓷修复体拆除前、拆除后1个月、拆除后3个月时,采用变性梯度凝胶电泳法检测镍铬合金烤瓷修复体基牙及对侧同名天然牙的龈下菌斑。结果与结论：修复体拆除后1,3个月,患牙龈下菌斑的变性梯度凝胶电泳图谱与拆除前相比均发生了明显变化,而且拆后3个月与拆后1个月相比也发生了较明显变化;此外,选择在修复体拆除前龈下菌斑中经常出现而在拆除后消失或减弱的变性梯度凝胶电泳图像中一些特异性条带作16S rDNA片段的序列分析,结果显示这些特异条带的基因序列分别与啮蚀艾肯菌、直形弯曲菌和隐藏优杆菌有着较高的序列相似度。结果表明镍铬合金烤瓷修复体导致了修复基牙龈下菌群组成的变化,并且导致了部分牙周可疑致病菌构成比增加。     

微量元素铬和硒与2型糖尿病的相关性研究

分析了微量元素铬、硒对2型糖尿病发病、发展及治疗的影响。重点讲述了2型糖尿病补充铬、硒的护理。     

Java medaka: a proposed new marine test fish for ecotoxicology

Java medaka (Oryzias javanicus), which is distributed in estuarine waters of East to Southeast Asia, is proposed here for consideration as a new marine test fish. Semi-static acute toxicity tests were conducted at 26 degrees C for 1 week, 2 weeks, and 1 month old Java-medaka exposed to 4-chlorophenol and zinc, and 2 weeks olds exposed to potassium dichromate (hexavalent chromium) and sodium hypochlorite (residue chlorine). Ninety-six hours LC50s of 4-chlorophenol, zinc, hexavalent chromium, and residue chlorine were from 3.0 to 4.1, from 12.4 to 14.7, 7.4, and 0.05 mg/L, respectively. There were no large differences in sensitivity for 4-chlorophenol and zinc among the three growth stages. Compared with other fish species, these LC50s were relatively low suggesting that Java medaka has relatively high sensitivity to chemicals. This fish is quite easy to keep in the laboratory, with low mortalities at early stages and it takes about 3 months to mature from hatching, suggesting that this fish can be used not only for short-term toxicity tests but also for early life stage toxicity tests. From these results, Java-medaka is highly recommended as a marine test fish for ecotoxicity tests.