• Safety and Health at Work
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• 제14권3호
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• pp.279-286
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• 2023

Background: This study aimed to evaluate the association between exposure to occupational hazards and the metabolic syndrome. A secondary objective was to analyze the additive and multiplicative effects of exposure to risk factors. Methods: This retrospective cohort was based on 31,615 health examinees at the Pusan National University Yangsan Hospital in Republic of Korea from 2012-2021. Demographic and behavior-related risk factors were treated as confounding factors, whereas three physical factors, 19 organic solvents and aerosols, and 13 metals and dust were considered occupational risk factors. Time-dependent Cox regression analysis was used to calculate hazard ratios. Results: The risk of metabolic syndrome was significantly higher in night shift workers (hazard ratio = 1.45: 95% confidence interval = 1.36-1.54) and workers who were exposed to noise (1.15:1.07-1.24). Exposure to some other risk factors was also significantly associated with a higher risk of metabolic syndrome. They were dimethylformamide, acetonitrile, trichloroethylene, xylene, styrene, toluene, dichloromethane, copper, antimony, lead, copper, iron, welding fume, and manganese. Among the 28 significant pairs, 19 exhibited both positive additive and multiplicative effects. Conclusions: Exposure to single or combined occupational risk factors may increase the risk of developing metabolic syndrome. Working conditions should be monitored and improved to reduce exposure to occupational hazards and prevent the development of the metabolic syndrome.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.861-862
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• 2012

• 한국소음진동공학회논문집
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• 제21권5호
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• pp.400-407
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• 2011

The suggested method of previous Son's study dichotomized subjective response data to modeling noise exposure-response. The method used maximum liklihood estimation instead of least square estimation and the noise exposure-response curve of the study was logistic regression analysis result. The method was originated to modeling community response rate such as %HA or %A. It can be useful when the subjective response was investigated based on predicted noise level. It is difficult to measure the single source emitting noise such as railway because various traffic noise sources combined in our life. The suggested method was adopted to model in this study and railway noise-exposure response curves were modeled because the noise level of this area was predicted data. The data of this study was used by previous Ko's paper but he dealt the area as combined noise area and divided the data by dominant noise source. But this study used all data of this area because the annoyance response to railway noise was higher than other noise according to the result of correlation analysis. The trend of the %HA and %A prediction model to train noise of this study is almost same as the model based on measured noise of previous Lim's study although the investigated areas and methods were different.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.433-438
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• 2001

This study is performed to evaluate hand-arm vibration syndrome(HA VS) of the workers in swaging process. Vibration measurement and assessment of human exposure are based on the international standard(ISO 5349). Triaxial acceleration of each operation and exposure time are measured to predict the periods before finger blanching, As results, it is found that acceleration is concerned with the diameter of pipes in swaging process, and also found that combined work is more harmful than a single operation.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 International Symposium
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• pp.58-69
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• 2003

Soil contamination in the United States is managed using a risk-based decision making process. In other words, we don't ask, 'how much soil contamination can be cleaned up\ulcorner' Instead we ask, 'how much contamination can be safely left in place\ulcorner' The determination of 'safe' levels of contamination is based upon the potential for exposure and the toxicity of the contaminants of concern in soil. Potential for exposure is determined by evaluating potential exposure pathways from source to receptor given current or reasonably anticipated land use. Soil cleanup goals are then calculated for any complete exposure pathways based upon toxicity and the route of exposure. In some cases, institutional or engineering controls are also used to limit the potential for exposure. In order to prevent a continuous degradation of environmental quality, risk-based cleanup approaches must be combined with strong contamination prevention programs. In addition, alternative risk management approaches should be incorporated into an overall risk reduction strategy.erall risk reduction strategy.

• 환경생물
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• 제20권4호
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• pp.277-286
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• 2002

An increase in the overall biological effect under the combined action of ionizing radiation with another inactivating agent can be explained in two ways. One is the supposition that synergism may attribute to a reduced cellular capacity of damn-ge repair after the combined action. The other is the hypothesis that synergism may be related to an additional lethal or potentially lethal damage that arises from the interaction of sublesions induced by both agents. These sublesions ave considered to be in-effective when each agent is applied separately. Based on this hypothesis, a simple mathematical model was established. The model can predict the greatest value of the synergistic effect, and the dependence of synergy on the intensity of agents applied, as well. This paper deals with the model validation and the peculiarity of simultaneous action of various factors with radiation on biological systems such as bacteriophage, bacterial spores, yeast and mammalian cells. The common rules of the synergism aye as follows. (1) For any constant rate of exposure, the synergy can be observed only within a certain temperature range. The temperature range which synergistically increases the effects of radiation is shifted to the lower temperature fer thermosensitive objects. Inside this range, there is a specific temperature that maximizes the synergistic effect. (2) A decrease in the exposure rate results in a decrease of this specific temperature to achieve the greatest synergy and vice versa. For a constant temperature at which the irradiation occurs, synergy can be observed within a certain dose rate range. Inside this range an optimal intensity of the physical agent may be indicated, which maximizes the synergy. As the exposure temperature reduces, the optimal intensity decreases and vice versa. (3) The recovery rate after combined action is decelerated due to an increased number of irreversible damages. The probability of recovery is independent of the exposure temperature for yeast cells irradiated with ionizing or UV radiation. Chemical inhibitors of cell recovery act through the formation of irreversible damage but not via damaging the recovery process itself.

• 월간산업보건
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• 통권87호
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• pp.53-54
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• 1995

• 한국축산시설환경학회지
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• 제3권1호
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• pp.1-12
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• 1997

This study was conducted to investigate the combined effects of VFA composition of rumen fluid and heat exposure (30${\pm}$2$^{\circ}C$) on the general clinical view and insulin secretory response to glucose in sheep. The total infusion of nutrients was examined in sheep via the technique of continuous alimentation. Four adult Suffolk sheep fitted with a permanent ruminal cannula and a simple T-shaped duodenal cannula were used. A peristaltic pump was used to infuse the solutions of volatile fatty acid triglycerides (VFA-TG) consisting of 70 triacetin : 20 tripropionin : 10 tributyrin (low propionin division: LP) and 50 triacetin : 40 tripropionin : 10 tributyrin (high propionin division: HP) on the basis of energy and minerals into the rumen, and casein solution into the duodenum. The effects of heat exposure and type of the levels of VFA-TG solutions on the insulin secretory response to glucose in sheep were investigated by using hyperglycemic clamp (HGC) technique. The results obtained are summarized as follows: 1. During the heat exposure (latter half of the infusion period), respiration rate, heart rate and rectal temperature increased (P＜0.01, P＜0.01, P＜0.05), but the levels of VFA-TG solutions (LP and HP division) did not affect the general clinical view except for the heart rate. 2. In the HGC technique, glucose infusion rate (GIR) and mean plasma insulin increments (MPII) tended to be ower in the heat exposure than in the thermoneutral environment, but no significant difference was found among the treatments. GIR and MPII remained unchanged between the levels of VFA-TG solutions. 3. In the HGC technique, ratio of MPII to GIR (MPII/GIR) which represents pancreatic ${\beta}$-cell response to glucose stimulation remained unchanged among the treatments.

• Corrosion Science and Technology
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• 제13권6호
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• pp.214-223
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• 2014

Interest in the durability assessment and structural performance has increased according to an increase of concrete structures in salt damage environment recent years. Reliable way ensuring the most accelerated corrosion test is a method of performing the rebar corrosion monitoring as exposed directly to the marine test site exposure. However, long-term exposure test has a disadvantage because of a long period of time. Therefore, many studies on reinforced concrete in salt damage environments have been developed as alternatives to replace this. However, accelerated corrosion test is appropriate to evaluate the critical chlorine concentration in the short term, but only accelerated test method, is not easy to get correct answer. Accuracy of correlation acceleration test depends on the period of the degree of exposure environments. Therefore, in this study, depending on the concrete mix material, by the test was performed on the basis of the composite degradation of the salt damage, and investigate the difference of corrosion initiation time of the rebar, and indoor corrosion time of the structure, of the marine environment of the actual environments were inuestigated. The correlation coefficient was derived in the experiment. Long-term exposure test was actually conducted in consideration of the exposure conditions submerged zone, splash zone and tidal zone. The accelerated corrosion tests were carried out by immersion conditions, and by the combined deterioration due to the carbonation and accelerated corrosion due to wet and dry condition.

• 대한의생명과학회지
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• 제13권3호
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• pp.231-237
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• 2007

Subway environments such as crowd, passenger's gab, or subway-generated mechanical noise may become a potential stressor. The present study was sought to determine whether subway noise with or without mental activity affects cerebral hemodynamics and sympathetic system. Fifty-four healthy volunteers were divided group I which underwent subway noise (n=24) and group II which underwent a combined mental activity (mental arithmetic) with subway noise (n=30). Sympathetic factors such as heart rate (HR), blood pressure (BP) and heart rate-systolic pressure product (RPP), and mean blood flow velocity in the middle cerebral artery (MCAV) were measured before (baseline), during and after the noise-exposure. Systolic and diastolic blood pressure, HR and RPP significantly increased in group II (P<0.05) but not in group I during the noise-exposure. Peak-MCAV, diastolic-MCAV and mean-MCAV in the both groups were elevated during the noise-exposure (P<0.05) and the increased ratios in group II were greater than those in group I. These results suggest that a combined mental activity with subway noise may be a stressor which affects cerebral hemodynamics and sympathetic system.