• Journal of Preventive Medicine and Public Health
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• v.27 no.1 s.45
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• pp.84-106
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• 1994

Hyperbaric oxygen (HBO) therapy for carbon monoxide (CO) poisoning eventually inducing the hypoxia-reoxygenation condition, may produce oxygen free radicals, which forms 8-hydroxydeoxyguanosine (8-OH-dG) by attacking C-8 position of deoxyguanosine (dG) in DNA. Effects of oxygen partial pressure or duration of HBO therapy with or without CO poisoning on the tissue 8-OH-dG formation were investigated. Male Sprague-Dawley rats were grouped and exposed to air (control group), 4000 ppm of CO for 10 to 30 minutes (CO only group), air for 30 minutes after 30 minute exposure to 4000 ppm of CO(CO-air exposure group), HBO after 30 minute exposure to 4000 ppm of CO(CO-HBO group), or HBO therapy fo. $10{\sim}120$ minutes(HBO only group). The 8-OH-4G concentrations in the brain and the lung tissues were measured with high performance liquid chromatography and electrochemical detector (ECD). Average concentrations of the 8-OH-dG of each group were statistically compared. In the brain tissues, 8-OH-dG concentrations of the CO only group, the CO-air exposure group, and the CO-HBO group did not significantly differ from those of the control group. Similar insignificance was also found between the CO-HBO group and the HBO only groups. No appreciable dose-response relationship was observed between the 8-OH-dG concentration and the oxygen partial pressure or the duration of HBO. However, the 8-OH-dG concentrations of the 30 minute CO only group were higher than those of the CO-air exposure group (p-value<0.05). In the lung tissues, there were no significant differences between the 8-OH-dG concentrations of the control group and those of the CO only group, the CO-air exposure group, and the CO-HBO group. However, mean 8-OH-dG concentration of the CO-air exposure group was significantly higher than that of the CO only group under the same CO exposure condition(p-value<0.05). With the duration of CO exposure, the 8-OH-dG concentrations of the lung tissues decreased significantly (p-value<0.05). The concentrations of 8-OH-dG in the lung tissues proportionally increased with the duration of HBO, but no such relation was observed with the oxygen partial pressure. These results suggest that the brain may be more resistant to oxygen free radicals as compared with the lungs, and that oxygen toxicity following HBO may be affected by factors other than oxygen free radicals.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.4
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• pp.323-329
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• 1995

The number of motor vehicles in Korea has increased to about 4 million, and the exhaust gases of these vehicles have become a more threatening factor to public health. Traffic policemen are one of the highest health risk groups since they work on roadsides where they are exposed to high levels of air pollutants. The health effects on them due to air pollution were determined by measuring personal carbon monoxide(CO) exposure and carboxyhemoglobin(COHb) level in blood. Thirty-one traffic policemen in Seoul volunteered to be subjects of the study. In October 1992, personal CO exposure was measured by a CO passive sampler. The subjects wore the CO passive sampler for 8 hours while on duty. The exposed samples were analyzed by gas chromatography. Blood samples from each subject were collected just after the exposure sampling, and were analyzed within 3 hours of blood collection by a CO-oximeter. The activities of the subjects were recorded by the subject in 30 minute intervals using an activity log sheet containing location and time spent. Personal CO exposure were ranged between 0.1 and 14.5ppm, eith an average of 5.9ppm. Carboxyhemoglobin levels ranged from 1.1% to 6.9%, with an average of 3.6%. policemen on duty outdoors had significantly higher CO exposures and COHb levels than policemen on duty indoors(p<0.01). Personal CO exposure and COHb were positively correlated, although the coefficient was not significant. The relationship between CO level and COHb level was confounded by smoking status. Among smokers, COHb level was significantly higher as CO exposure and hours worked outdoors increased.

• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.7-16
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• 1991

Measurement of Co-60 gamma rays has been made for establishment of exposure standard and analyze it's overall uncertainties. Exposure rate determined by the charge mode method using vibrating reed amplifier with cylinderical type cavity chamber. The values of a variety of physical constants and the correction factors are evaluated. The resulting exposure rate is 690.81 R/h at the distance of 1m from the source and the related uncertainties is ${\pm}0.8%$

• Safety and Health at Work
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• v.11 no.1
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• pp.33-40
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• 2020

Background: Exploratory study to investigate whether co-exposure to physical wrist stressors and chemicals is associated with carpal tunnel syndrome (CTS) in French male farmers and agricultural workers. Methods: Cross-sectional study of 711 men aged 30-65 years and working as either farmers or agricultural workers in 2009-2010 within a cohort covered by the French Agricultural Workers' and Farmers' Mutual Benefit Fund. CTS and exposure to physical wrist stressors and chemicals were assessed using a self-administered questionnaire. Associations between CTS and personal/medical factors, exposure to physical wrist stressors, exposure to chemicals, and co-exposure to physical wrist stressors and chemicals were studied using multivariate logistic regression models. Results: Forty-four men {5.6% [95% confidence interval (CI) 4.0-7.7]} reported that they had suffered from unilateral/bilateral CTS during the last 12 months. CTS was associated with age, current smoking [odds ratio (OR) = 2.1 (1.0-4.5)], and exposure to physical wrist stressors [OR = 2.6 (1.1-5.9)]. An association was found between CTS and co-exposure to physical wrist stressors and chemicals [OR = 3.3 (0.8-14.3), p = 0.044] in comparison with the no-exposure group. Conclusions: This exploratory study shows an association of CTS with exposure to biomechanical wrist stressors in male farmers and agricultural workers and suggests an association of CTS with co-exposure to physical wrist stressors and chemicals. Owing to the limitations of the study, this result must be confirmed by a prospective study with objective assessments of the outcome and exposure before drawing conclusions on the possible synergistic effects of mechanical stressors and chemicals on the impairment of the median nerve.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.208-209
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• 2009

• Journal of Mushroom
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• v.2 no.2
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• pp.45-48
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• 2004

The effect of $CO_2$ concentration (500, 3,000, $6,000{\mu}{\ell}/{\ell}$) on the mycelial growth and fruit body primordium formation of Ganoderma lucidum on nutrient agar medium was examined. Optimum $CO_2$ concentration for vegetative growth was above $3,000{\mu}{\ell}/{\ell}$. Fruit body initiation was accelerated at higher than $3,000{\mu}{\ell}/{\ell}$ $CO_2$ exposure but the maximum number and size of primordia, and primordium color were not influenced by $CO_2$ concentrations. Whereas each atypical fruiting structure forming stock culture showed different fruiting time under each concentration of $CO_2$ exposure.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.97-102
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• 1990

A pilot field study was conducted to measure indoor and personal exposure to carbon monoxide (CO) levels using personal monitors from January to February in 1989. The principal objectives of the study was to design and evaluate the research protocol and the instrumentation performance for application to the conduct of a large-scale personal monitoring program. The mean CO concentrations in kitchen and in bedroom were 23.4 and 11.9 ppm, respectively, while mean concentration of personal CO exposure was 18.9 ppm. It was found that the mean CO concentrations in kitchen exceeded 20 ppm of the Korea ambient CO standard(8-hr average) not to be exceeded more than three times per year. The results suggest that indoor CO levels in Korean houses appear to be affected by use of coal briquette for heating any cooking.

• Toxicological Research
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• v.34 no.3
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• pp.211-220
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• 2018

Early life exposure to aflatoxin B1 (AFB1) and low protein diet through complementary foods during weaning is common in parts of Africa and Asia. This study evaluated the effect of co-exposure to AFB1 and low protein diet on the extrahepatic tissues of rats. Twenty-four three-week old weanling male albino rats were used for this study and were randomly assigned into four groups: group 1 served as control and was fed normal protein diet (20% protein), group 2 was fed low protein diet (5% protein), group 3 was fed normal protein diet + 40 ppb AFB1 while group 4 received low protein diet + 40 ppb AFB1, all for eight weeks. Afterward, biomarkers of anemia (packed cell volume (PCV), hemoglobin) and kidney function (urea, uric acid, and creatinine) were determined in the blood while biomarkers of oxidative stress were determined in the tissues spectrophotometrically. Co-exposure to AFB1 and low protein diet significantly (p < 0.05) decreased body weight gain and PCV, increased biomarkers of kidney functions and induced oxidative stress in the tissues studied. There was significant (p < 0.05) reduction in glutathione concentration while TBARS was significantly increased in the tissues. Co-exposure to AFB1 and low protein diet had additive effects on decreasing the weight gain and potentiation effect of kidney dysfunction in the rats. The co-exposure also decreased antioxidant enzymes and increased oxidant status in the tissues. Our results demonstrate that this co-exposure has deleterious health effects on extrahepatic tissues and should be a public health concern especially in developing countries where AFB1 contamination is common.

• Journal of Preventive Medicine and Public Health
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• v.24 no.4 s.36
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• pp.507-515
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• 1991

One, two, six and ten week old Sprague-Dawley rats were exposed to carbon monoxide at 3,700 ppm for 30 minutes, and carboxyhemoglobin was measured immediateley. 5, 30, 60, 90, 120 minutes after the exposure. In each time after the exposure, the means of the carboxyhemoglobin levels were compared among the week age groups. The regression analysis was done using the natural logarithm of the carboxyhemoglobin concentration as a dependent variable and the time after the exposure as an independent vaiable. From the regression equation, the half lives of the carboxyhemoglobin were calculated. The one week old rats showed significantly higher carboxyhemoglobin level than other week age rats in the entire time after the exposure. The corrected carboxyhemoglobin concentration calculated by subtracting the normal carboxyhemoglobin level from the measured carboxyhemoglobin at each age group, showed no uniform differences.

• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.29-37
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• 2016

CO₂ injection well sealant is vulnerable to supercritical CO₂ (scCO₂) exposure. To develop an alternative to the conventional sealant system (class G cement/class F fly ash), the performance of slag cement (SPC) systems containing class F fly ash (FFA) or class C fly ash (CFA) was evaluated and compared with the conventional sealant under scCO₂ conditions. All sealant systems showed an immediate increase in compressive strength upon scCO₂ exposure and, at 37.6 MPa, SPC/CFA showed the highest compressive strength after 14 days, which was much higher than the 29.8 MPa of the conventional sealant system. Substantial decreases in porosity were observed in all sealant systems, which were partly responsible for the increase in strength. Carbonation reactions led to pH decreases in the tested sealants from 12.5 to 10~11.6. In particular, the greatest decrease in pH in slag cement/class C fly ash probably supported relatively sustainable alkali activation reactions and the integrity of cement hydrates in this system. XRD revealed the presence of CaCO₃ and a decrease in the content of cement hydrates in the tested sealants upon scCO₂ exposure. TGA demonstrated a greater increase of CaCO₃ and calcium-silicate-hydrate phases in SPC/CFA than in the conventional sealant upon scCO₂ exposure.