In this study, we have demonstrated feasibility of a semi-quantitative approach for the estimation of cellular SiO 2 nanoparticles (NPs), which is based on the flow cytometry measurements of their normalized side scattering intensity. In order to improve our understanding on the quantitative aspects of cell-nanoparticle interactions, flow cytometry, transmission electron microscopy, and X-ray fluorescence experiments were carefully performed for the HeLa cells exposed to SiO 2 NPs with different core diameters, hydrodynamic sizes, and surface charges. Based on the observed relationships among the experimental data, a semi-quantitative cellular SiO 2 NPs estimation method from their normalized side scattering and core diameters was proposed, which can be applied for the determination of cellular SiO 2 NPs within their size-dependent linear ranges. V C 2014 International Society for Advancement of Cytometry

No abstract

The extrinsic physicochemical properties of nanoparticles (NPs), such as hydrodynamic size, surface charge, surface functional group, and colloidal stabilities, in toxicity testing media are known to have a significant influence on in vitro toxicity assessments. Therefore, interpretation of nanotoxicity test results should be based on reliable characterization of the NPs’ extrinsic properties in actual toxicity testing media. Here, we present a set of physicochemical characterization results for commercially available ZnO NPs, including core diameter, hydrodynamic diameter, surface charges, and colloidal stabilities, in two in vitro toxicity testing media (Roswell Park Memorial Institute [RPMI] and Dulbecco’s Modified Eagle’s Medium [DMEM]), as well as simple cell viability assay results for selected ZnO NPs. Four commercially available and manufactured ZnO NPs, with different core sizes, were used in this study, and their surface charge was modified with five different surface coating materials (sodium citrate, tris(2-aminoethyl)amine, poly(acrylic acid), poly(allylamine hydrochloride), and poly-L-lysine hydrochloride). The results showed that ZnO NPs were better dispersed in cell culture media via surface modification with positively or negatively charged molecules. Moreover, in the presence of fetal bovine serum (FBS) in RPMI and DMEM media, ZnO NPs were found even better dispersed for a longer period (at least 48 hours). For the HeLa cells exposed to ZnO NPs in DMEM media without FBS, surface charge-dependent cytotoxicity trends were observed, while these trends were not observed for those cells cultured in FBS-containing media. This confirmed the important roles of surface-modifying compounds and of surface charge on the resultant cytotoxicities of NPs.

No abstract

No abstract

In this study, focusing on the 'Focused on the 9th Occupational Safety and Health Survey Data', the existence of risk factors in the workplace and the relevance of the occurrence of industrial accidents are confirmed, and based on this, the existence of risk factors is identified in advance and safety and health management measures to reduce occupational accidents. It was carried out for the purpose of use as basic data for establishment. Among the raw data of ‘Focused on the 9th Occupational Safety and Health Survey Data’, 5,108 workplaces were selected for final analysis. The data are divided by industry, and the size of the workplace (number of workers), the occurrence of industrial accidents (as of 2017), mental/psychological, chemical substances, physical, ergonomics, presence of dangerous machinery/equipment, and the presence or absence of risk factors for work in hazardous places are 6 Statistical analysis was performed using the items. As a result, the occurrence of industrial accidents by industry was highest in the construction industry, manufacturing industry, and service industry. In the manufacturing and service industries, the larger the workplace, the higher the occurrence of industrial accidents, and in the construction industry, the occurrence of workplaces with 100 or more workers was higher. In the relationship between companies, in the manufacturing and service industries, the occurrence of industrial accidents among in-house subcontractors of the prime contractor was high, and in the construction industry, the occurrence of industrial accidents was high in the workplaces other than the principal and subcontractors. As for the presence of risk factors in the workplace, the presence of hazardous machinery and equipment risk factors in the manufacturing industry, mental and psychological risk factors in the service industry, and the presence of risk factors in dangerous places in the construction industry were found to be the highest. difference in existence. Occupational accidents were found to be highly correlated when risk factors were present. Through this study, it was confirmed that the relationship between the business type, size, and company of the workplace is related to the occurrence of industrial accidents. In addition, although the presence of risk factors in the workplace is highly related to the occurrence of industrial accidents, there are differences according to the industry. The safety and health system of the workplace should be established after identifying the characteristics of the workplace and the existence of risk factors in advance, and improvement and countermeasures should be prepared by identifying harmful risk factors through the search for accidents occurring at the workplace and discovering potential risk factors.

The current Occupational Safety and Health Act does not apply the regular safety and health education provisions of Article 32 of the Act to businesses that employ only office workers. However, it is stipulated that regular safety and health education of at least 3 hours per quarter is required for office workers working in the field. However, office workers are also at risk of being exposed to long hours of work, emotional labor, and musculoskeletal disorders, and it seems that there is no small need for safety and health education. Therefore, this study was conducted to classify office workers into general office workers and field office workers, to understand the actual situation of safety and health education, and to verify the necessity and economic effect of safety and health education and use it as evidence for expanding the subject of education. In this study, first, in order to understand the status of safety and health education of office workers, a survey was conducted on 123 office workers and statistical analysis was performed using frequency analysis and multiple response analysis. Second, to confirm the effect of safety and health education, using the 2018 workplace safety and health survey and the 2019 industrial accident statistics accident rate, we quantified the effect of education for office workers on the occurrence of industrial accidents and estimated the benefits of the effect of reducing industrial accidents. As a result of the study, it was found that general office workers' accident experience and awareness of accidents and diseases were higher than those of on-site office workers, and the subjects of safety and health education were supervisors and safety and health managers, and education was mainly provided by internal employees. The awareness of the effectiveness of regular safety and health education was high at 89.4%, and the need for flexible operation of training hours and an increase in the number of training sessions to vitalize regular safety and health education was found to be high. In particular, there was a high awareness that it was necessary to expand ‘outsourced education support’ for revitalization of education in small businesses and to manage ‘confirmation of safety and health education’ in order to establish regular safety and health education. Compared to workplaces that do not provide training, the effect of preventing industrial accidents is higher, and thus it is expected to contribute to the reduction of accidents and labor loss. Through this study, it was possible to confirm the perception that safety and health education is necessary for general office workers in addition to the field, and it was identified that flexible operation of education suitable for the characteristics of the workplace and management of workplace implementation were necessary.

No abstract