As radon is a naturally occurring radioactive gas that can cause lung cancer and is classified as a Group 1 carcinogen, it is essential for the public to be aware of what radon is, and how to manage radon. Therefore, general information on radon, as well as its health risks, measurement methods, mitigation methods and suggestions for its management are addressed in this article. Over the last one to two decades, a number of wide-ranging studies on radon measurement and mitigation have been conducted in Korea, and the results of each study are comparable to the research achievements of other developed countries. For this reason, it is time to systematically establish a well-made Korean radon management organization.

This study analyzed the total number of 19,636 patients and radiation technologists, 11,433 of male and 8,203 of female by examined body parts, age, types of detectors, the using contrast enhancement and working condition of the technologists, regular staffs or rotation-duty staffs, based on the K-DOS program distributed by FDA with the DLP value of diagnostic evaluation. The result shows that the effective radiation dose was 0.7mSv~41.7mSv for each region and male patients had more radiation exposure than females. And the amount of exposure was also affected by the types and the method of detectors. Furthermore, the regular staffs took the role of helping the patient to get reduced amount of radiation exposure than rotation duty-staffs. Computed tomography (CT) use has increased dramatically over the past several decades. In this reason, to support the patients and the workers’ health in the field, the hospitals should apply specialized regular working radiation technologist system and manufacturing companies of those CTs should develop low medical radiation exposure devices.

The objective of this study is to safety assessment for human body on the guided missile combustion products. This study is to verify the safety assessment when operating the interior missile ejection take on verify the safety of the human body. During the missile ejection of combustion products, this study is analyzed combustion products. Result are accepted NIOSH and KOSHA of the safe guideline, and 6 exposure gas to the specified values 42% (CO), 22% (CO2), not detected (others) are within minimal exposures criteria of the reference value respectively. Contribution of these results supported that interior missile ejection during combustion products may have been ensured human safely. Therefore, the future for improving the environmental safety of the shooting projectile steel plate round, dust collector, ventilation and other facilities is to improve environmental safety and efficient renovated design needed by target focused areas.

Human gingival fibroblasts (hGFs) were reported to play an important role in inflammatory reactions to lipopolysaccharide (LPS) from P.gingivalis in the periodontal connective tissue. Although the biostimulatory effects of hyperbaric oxygen therapy, such as anti-inflammatory activity, have been reported, the pathological mechanism is not completely understood. This study examined the changes in the inflammatory cytokine profiles, which are produced after exposure to hyperbaric oxygen in P.gingivalis LPS-treated human gingival fibroblasts, and subsequently to examine the mitogen activated protein kinase (MAPK) pathway involved in cytokine production. Gingival fibroblasts with or without P.gingivalis LPS were exposed to hyperbaric oxygen, and the cytokine profiles in the supernatant were observed using a human inflammation antibody array. The expression of cyclooxyginase-2 (COX-2) protein, phosphorylation of extracellular signal-regulated kinase (ERK1/2), p38, and c-Jun-N-terminal kinase (JNK) MAPK by western blot analysis, and the amount of prostaglandin E2 (PGE2) in the supernatant by an enzyme-linked immunoassay were determined. COX-2 protein expression and PGE2productionwereincreasedsignificantlyintheP. gingivalis LPS-treated group, and were decreased by treating P. gingivalis LPS with hyperbaric oxygen. Treatment of P. gingivalis LPS in the gingival fibroblasts led an increase in the amount of pro-inflammatory-related cytokines interleukin-6 (IL-6) and IL-8 released, whereas hyperbaric oxygen inhibits the irrelease. Ananalysis of the MAPK signal transduction showed that hyperbaric oxygen induced a significant decrease in the level of P38 phosphorylation regardless of the presence or absence of LPS. In addition, hyperbaric oxygen promoted JNK phosphorylation, significantly in the presence of LPS. Hyperbaric oxygen can inhibit pro-inflammatory cytokines and mediate the MAPK signal pathway, and appears to be useful as an anti-inflammatory tool.

This study examined the effects of red light generated from a light emitting diode (LED) upon proliferation and mitochondrial stress in human gingival fibroblasts (hGFs). Cells were exposed to LED-generated red light at a clinically relevant intensity and distance with a 610-630 nm wavelength for various times (0-48 min). At different exposure times, cells were processed for the analysis of succinate dehydrogenase (SDH) activity, proliferation, mitochondrial membrane potential (MMP) and cytotoxicity. Cell cycle progression was also investigated by flow cytometry after staining with propidium iodide. Red light exposure was found to inhibit SDH activity and DNA synthesis in hGFs in a time-dependent manner. Light exposure also reduced the MMP levels in these cells and this was closely associated with a G0/G1 arrest. In contrast, exposure of hGFs to red light for 48 min led to a dramatic loss of MMP with an attendant increase in cytotoxicity. These findings demonstrate that LED-generated red light may cause mitochondrial stress and growth inhibition in hGFs during tooth whitening therapy, depending on the length of the exposure.

Highly homogeneous and functional stem cell-derived hepatocyte-like cells (HLCs) are considered a promising option in the treatment of liver disease and the development of effective in vitro toxicity screening tool. However, the purity of cells and expression and/or activity of drug metabolizing enzymes in stem cell-derived HLCs are usually too low to be useful for clinical or in vitro applications. Here, we describe a highly optimized differentiation protocol, which produces more than 90% albumin-positive HLCs with no purification process. In addition, we show that hepatic enzyme gene expressions and activities were significantly improved by generating three-dimensional (3D) spheroidal aggregate of HLCs. The 3D differentiation method increased expressions of nuclear receptors that regulate the proper expression of key hepatic enzymes. Furthermore, a significantly increased hepatic functions such as albumin and urea secretion were observed in 3D hepatic spheroids and HLCs in the spheroid exhibited morphological and ultrastructural features of normal hepatocytes. Importantly, we show that repeated exposures to xenobiotics facilitated the functional maturation of HLC, as confirmed by increased expression of genes for drug metabolizing enzymes and transcription factors. In conclusion, the 3D culture system with repeated exposures to xenobiotics may be a new strategy for enhancing hepatic maturation of stem cell-derived HLCs as a cell source for in vitro high-throughput hepatotoxicity models.