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Park J.,Yonsei University | Lim D.-H.,Yonsei University | Lim H.-J.,Yonsei University | Kwon T.,National Institute of Scientific Investigation | And 4 more authors.
Chemical Communications | Year: 2011

The immune-response of macrophages is an important area of investigation since it represents the major pathway by which early-stage defense barriers are established in skin, lungs, and mucosal systems to counteract foreign objects. In this study, we have examined the size-dependent inflammatory and toxicological effects of nanostructured silver particles (nano-Ag) on macrophage immune cells. © 2011 The Royal Society of Chemistry. Source

Kim E.S.,National Institute of Scientific Investigation
Transactions of the Korean Society of Mechanical Engineers, A | Year: 2011

Forensic Engineering is the art and science of professionals qualified to serve as engineering experts in courts of law or in arbitration proceedings. Buses using compressed natural gas (CNG) trend to be extended in use internationally as optimal counterplan for reducing discharge gas of light oil due to high concern about environment. However, CNG buses have to be equipped with composite pressure vessels (CPVs); since the CPVs contain compressed natural gas, the risks in the case of accident is very high. Hence, the investigation of such accidents is usually associated with engineering analysis. Among the possible reasons for such CNG explosion accidents is vehicle fire and vessel fracture. By conducting formal inspection and engineering tests, in this study, the cause of vessel explosion is investigated by analyzing the failure mechanism by fractography and by comparing the material properties of a reference part with those of a problem part by adopting instrumented indentation technique. © 2011 The Korean Society of Mechanical Engineers. Source

Park S.-J.,Korea University | Chae S.-W.,Korea University | Kim E.-S.,National Institute of Scientific Investigation
International Journal of Automotive Technology | Year: 2010

Neck fracture is a major cause of death in traffic accidents. This pattern of injury normally occurs in a frontal collision or overturn of a vehicle. This study investigates the case of a neck fracture from a low-speed collision. In the examined case, the passenger in the front seat of the car fractured his neck and died. He did not have his seatbelt on when the vehicle slipped on a frozen road surface on a downward slope of a hill and impacted into the shoulder of the road at low speed. In this type of collision, an occupant's body will be impacted by the windshield or other interior trim of the car. However, in this case, rather unusually, neither body tissue nor fiber remained although the collision involved a broken windshield. Thus, the reason for the passenger death was unidentified. This study applied the computer simulation package Madymo for analyzing the accident. The result of the simulation was that the passenger, who did not wear a seatbelt, moved forward due to inertia. The upper part of the passenger then rotated and lifted when the knee contacted with the dashboard. By evaluating the structural deformation of the vehicle at the front, we deduced that the collision velocity was 30 km/h. Through a computational experiment that was undertaken using Madymo 7.0, NIC was estimated to be 240 m2/s2. This result far exceeded the threshold for neck injuries. In particular, in comparison with whiplash injuries, when the passenger's head directly impacts the roof following a rear-end collision, the bending moment through hyperextension of the neck is greatly increased. In this study, we concluded that the manner of death was the hyperextension of the neck, as the passenger's head contacted the roof from underneath. © 2010 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg. Source

Kim E.S.,National Institute of Scientific Investigation
Transactions of the Korean Society of Mechanical Engineers, A | Year: 2010

Forensic engineering is the area of expertise of people qualified to serve as engineering experts in courts of law or during arbitration proceedings. An aerial-lifter can lift and carry load, including people, using power. Recently, failure of aerial-lifter internal parts while working and sweeping causing injuries and damage to property almost always generates conflict between the automaker and customer. Hence, the investigation of such events generally involves an engineering analysis. One of the possible reasons for accidents, such as a vehicle catching fire is the failure of oil pressure machine and the supporting pin. The results of formal inspections and engineering tests can reveal the cause for the failure of the mechanical parts. Therefore, the failure mechanism is analyzed by adopting fractography methods and by applying an instrumented indentation technique to compare the material properties of the reference part with those of the malfunctioning part. © 2010 The Korean society ot Mechanical Engineers. Source

Oh S.M.,Hoseo University | Kim H.R.,Sungkyunkwan University | Park Y.J.,Sungkyunkwan University | Lee S.Y.,National Institute of Scientific Investigation | Chung K.H.,Sungkyunkwan University
Mutation Research - Genetic Toxicology and Environmental Mutagenesis | Year: 2011

Traffic is a major source of particulate matter (PM), and ultrafine particulates and traffic intensity probably contribute significantly to PM-related health effects. As a strong relationship between air pollution and motor vehicle-originated pollutants has been shown to exist, air pollution genotoxicity studies of urban cities are steadily increasing. In Korea, the death rate caused by lung cancer is the most rapidly increased cancer death rate in the past 10 years. In this study, genotoxicity of PM2.5 (<2.5μm in aerodynamic diameter particles) collected from the traffic area in Suwon City, Korea, was studied using cultured human lung bronchial epithelial cells (BEAS-2B) as a model system for the potential inhalation health effects. Organic extract of PM2.5 (CE) generated significant DNA breakage and micronucleus formation in a dose-dependent manner (1μg/cm3-50μg/cm3). In the acid-base-neutral fractionation of PM2.5, neutral samples including the aliphatic (F3), aromatic (F4) and slightly polar (F5) fractions generated significant DNA breakage and micronucleus formation. These genotoxic effects were significantly blocked by scavenging agents [superoxide dismutase (SOD), sodium selenite (SS), mannitol (M), catalase (CAT)]. In addition, in the modified Comet assay using endonucleases (FPG and ENDOIII), CE and its fractions (F3, F4, and F5) increased DNA breakage compared with control groups, indicating that CE and fractions of PM2.5 induced oxidative DNA damage. These results clearly suggest that PM2.5 collected in the Suwon traffic area has genotoxic effects and that reactive oxygen species may play a distinct role in these effects. In addition, aliphatic/chlorinated hydrocarbons, PAH/alkylderivatives, and nitro-PAH/ketones/quinones may be important causative agents of the genotoxic effects. © 2011 Elsevier B.V. Source

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