A portable TDCR system

The triple-to-double-coincidence ratio method (TDCR) is an important method for activity standardization in metrology institutes worldwide. There is an increasing interest in portable systems that allow activity determination outside of specialized laboratories with high accuracy. Within the framework of the EMRP “MetroFission” project, several portable systems using different designs were developed. The PTB system described here is based on channel photomultipliers incorporated in a portable detection module, a separate electronics bin and a computer for data acquisition and storage. This miniature TDCR system was extensively tested and compared to the PTB reference TDCR system that is very well characterized and has been used in several intercomparisons.     

Biological response and morphological assessment of individually dispersed multi-wall carbon nanotubes in the lung after intratracheal instillation in rats

Biological responses of multi-wall carbon nanotubes (MWCNTs) were assessed after a single intratracheal instillation in rats. The diameter and median length of the MWCNTs used in this study were approximately 60 nm and 1.5 μm, respectively. Groups of male Sprague–Dawley rats were intratracheally instilled with 0.04, 0.2, or 1 mg/kg of the individually dispersed MWCNT suspension. After instillation, the bronchoalveolar lavage fluid was assessed for inflammatory cells and markers, and the lung, liver, kidney, spleen, and cerebrum were histopathologically evaluated at 3-day, 1-week, 1-month, 3-month, and 6-month post-exposure. Transient pulmonary inflammatory responses were observed only in the lungs of the group of rats exposed to 1 mg/kg of MWCNTs. Morphology of the instilled MWCNTs in the lungs of rats was assessed using light microscopy and transmission electron microscopy (TEM). Light microscopy examination revealed that MWCNTs deposited in the lungs of the rats were typically phagocytosed by the alveolar macrophages and these macrophages were consequently accumulated in the alveoli until 6-month post-exposure. The 400 TEM images obtained showed that all MWCNTs were located in the alveolar macrophages or macrophages in the interstitial tissues, and MWCNTs were not located in the cells of the interstitial tissues. There was no evidence of chronic inflammation, such as angiogenesis or fibrosis, induced by MWCNT instillation. These results suggest that MWCNTs were being processed and cleared by alveolar macrophages.     

Cellular effects of manufactured nanoparticles: effect of adsorption ability of nanoparticles

Nanoparticles are important industrial materials. However, many nanoparticles show biological effects, including toxic activity. Metal ion release is the most important factor affecting the biological effects of nanoparticles. In addition, nanoparticles have large adsorption ability. The adsorption ability, in particular protein adsorption to nanoparticles, has an effect on cellular uptake and cellular metabolisms. Moreover, the adsorption ability of nanoparticles causes artificial effects in in vitro systems. Consequently, accurate determination of released or secreted proteins such as lactate dehydrogenase and cytokines adsorbed to nanoparticles is affected. In addition, artificial effects cause overestimation or underestimation of the cytotoxicity of nanoparticles. Therefore, measurement of the protein adsorption of nanoparticles is important. Some methods for the determination of the adsorption to nanoparticles have been suggested. The flow field-flow fractionation method is one of the efficient techniques for determining proteins on the surface of nanoparticles. The cellular effects caused by nanoparticles should be carefully considered.     

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.     

Vaccine versus infection – COVID-19-related loss of training time in elite athletes

ObjectivesTo determine the number of training days lost due to COVID-19 and vaccination against COVID-19 in elite athletes.DesignRetrospective cohort study.MethodsThe questionnaire on the impact of vaccination and COVID-19 on training plans was filled out by 1073 elite Polish athletes who underwent routine medical screening between September and December 2021.ResultsCOVID-19 was diagnosed in 421 subjects (39 %), of whom 26 % were asymptomatic. On the 10-point scale, <1 % of athletes had perceived severity of the disease above 8, whereas for 64 % it was 4 or below. Vaccination against COVID-19 was administered in 820 athletes (76 %), and adverse events were observed more frequently after the first dose than the second (69 % vs. 47 %).Influence on training (modified or lost) was declared by 369 of 421 (88 %) COVID-19 athletes, and by 226 of 820 vaccinated athletes (28 %). During the observation period, the average number of lost training days was 8.1 for COVID-19 and 2.6 for vaccination (p < 0.001). The cumulative number of person-days lost due to COVID-19 was 1041 versus 295 after vaccination thus, the average loss ratio was 1041/1073 = 0.97 vs. 295/820 = 0.36, respectively, p < 0.01.ConclusionsAthletes have a considerable loss of training days due to COVID-19. Vaccination against COVID-19 causes significantly smaller and predictable loss. This supports the inclusion of vaccination into prevention policies for athletes whenever they are available.     

2015—2019年全国外照射个人剂量监测能力考核结果分析与总结

目的规范个人剂量监测技术服务机构的个人剂量监测工作,提高监测能力和水平。方法汇总2015—2019年全国外照射个人剂量监测能力考核的结果,并对考核中出现的问题进行总结与分析。结果截至2019年,来自全国30个省、自治区或直辖市的个人剂量监测技术服务机构参加了全国外照射个人剂量监测能力考核,涉及的机构有疾控中心、职防院(所)、科研院所、大专院校、核工业、医疗机构及民营技术机构等。参加考核的机构数从202家增加到382家。考核结果除2017年的合格率略低,其他4年的合格率均高于90%。优秀率随着年份的增加而增加。结论2015—2019年全国外照射个人剂量监测技术服务机构测量能力满足个人剂量监测需求,能出具符合标准的检测报告,但尚有一些机构未能合格,相关机构应仔细分析查找不合格的原因,规范实验室的质量控制手段,提高测量水平和数据分析能力。