• Safety and Health at Work
• /
• v.2 no.3
• /
• pp.290-300
• /
• 2011

Objectives: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods: Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results: In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion: When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.

• Korean Journal of Veterinary Research
• /
• v.39 no.1
• /
• pp.62-69
• /
• 1999

Although it has been reported that hormones or chemicals, which increase in intracellular cAMP, produced $Mg^{2+}$ release from the heart, it is not well characterized whether a specific $Mg^{2+}$ exchanger is involved in cAMP-induced $Mg^{2+}$ efflux in the mammalian hearts. In this work, we studied the relationship between the increase in intracellular cAMP and ion transport system on $Mg^{2+}$ regulation in the perfused rat heart and isolated myocytes. The $Mg^{2+}$ content in the perfusate and supernatant were measured by atomic absorption spectrophotometer. The addition of membrane permeable cAMP analogue to the perfused hearts and myocytes induced a $Mg^{2+}$ efflux in the dose dependent manners. $Mg^{2+}$ efflux was stimulated by cAMP modulators (forskolin, IBMX and Ro20-1724) in the perfused hearts and myocytes. cAMP-induced $Mg^{2+}$ efflux was inhibited by $H_7$, benzamil or imipramine in the perfused hearts and myocytes, but not by EIPA. We confirmed that a significant $Mg^{2+}$ efflux was induced by an increase in intracellular cAMP in the hearts and myocytes. The cAMP-induced increase of $Mg^{2+}$ efflux in the hearts may be involved in ion transport system ($Na^+-Ca^{2+}$ and $Na^+-Mg^{2+}$ exchanger).

• Journal of the Korean Society of Safety
• /
• v.7 no.3
• /
• pp.30-34
• /
• 1992

This study is conducted to evaluate the airborne concentration of mercury, as well as installation and efficiency of local exhaust ventilation system for 57 factories manufactured fluorescence lamps, mercury lamps and thermometers for July and August 1990. Results and conclusion are as fellows : 1) Mercury treatment factories are 32 among 57 ones, which are 18 fluorescence lamp manufacturing ones and 6 mercury lamp ones and 3 thermometer ones and 5 other ones. 2) Mean airborne concentrations of mercury for factories manufactured mercury lamps are 0.01 mg/ ㎥ in injection process and 0.0155mg/㎥ in exhaust process, and mean airborne concentration of mercury for factories manufactured thermometer are 0.023mg/㎥ in injection process and 0.012mg/㎥ in selection process. All of these airborne concentrations of mercury are lower than PEL(Permissible Exposure Limit ), 0.05mg/㎥. 3) Mean airborne concentrations of mercury for factories manufactured fluorescence lamps are 0.094mg/㎥ in injection process and 0.087mg/㎥ in exhaust process, and 0.052mg/㎥ in sealing process and 0.085mg/㎥ in other process, respectively. All of these air borne concentrations of mercury are exceeded to PEL. More than 60% among 32 factories manufactured mercury are exceeded to PEL. 4) Nine factories among 18 factories manufactured fluorestence lamps are equipped with local exhaust ventilation system, and 7 factories among 9 factories are required for the improvement of suction capacity and structure. Five factories among 14 factories manufactured mercury lamps and the other ones are equipped with local exhaust ventilation system, and 2 factories are required for the improvement of suction capacity and structure.

• Korean Journal of Construction Engineering and Management
• /
• v.25 no.2
• /
• pp.3-10
• /
• 2024

The purpose of this study is to analyze the effects of smart construction equipment applied at the construction site of the first smart city in the Korea and derive an application strategy for the utilization of smart construction equipment. To achieve this, aythors examined the practical effects and issues of safety systems and construction systems utilizing machine guidance (MG) technology, which is a representative smart construction equipment used in civil engineering construction sites. Both the MG safety system and MG construction system were found to be sufficiently effective in improving construction productivity. However, there are challenges that need to be addressed, such as the approval process for work results using MG systems, system changes due to frequent replacement of on-site equipment, and usability improvements for elderly on-site workers. The study presented some solutions that have been implemented on-site to address these issues. The utilization effects and issues presented in the study were analyzed through direct feedback from workers and managers who have utilized the MG technology on-site for a considerable period of time. These results can be used as preliminary data for the similar construction projects, considering the limited availability of empirical analysis data for equipment automation.

• Journal of Energy Engineering
• /
• v.10 no.2
• /
• pp.132-139
• /
• 2001

석탄가스화 복합발전의 집진 공정에 사용하기 위한 금속제 safety filter의 재질 선정을 위하여 황화수소 가스 분위기에서 합금강의 부식 특성을 규명하였다. 사용 합금강은 SUS 310, SUS 316, Inconel 600과 Hastelloy X이다. 전기로 내에 설치된 지름 50mm의 qualtz 튜브 반응기에서 부식실험이 행하여졌다. 40$0^{\circ}C$부터 $700^{\circ}C$까지의 등은 조건에서 실험이 행하여졌고, 분위기 가스의 영향을 보기 위하여 H$_2$S 가스를 함유한 $N_2$(dry), $N_2$(saturation), $CO_2$(dry), 그리고 석탄가스 분위기에서 실험하였다. 부식 생성물을 파악하기 위하여 X-ray 회절기와 주사전자현미경 분석이 함께 이루어졌다. 1.7% H$_2$S, $600^{\circ}C$ 이하 온도 조건에서는 니켈계 내식강 중 Hastelloy X와 철계 내식강 중 SUS 310 등 고크롬 합금강이 IGCC 용 필터 소재 금속으로서 높은 내부식성을 나타내었다. 0.3%~4.99% 황화수소 농도 범위에서 황화수소 농도 변화에 따라서 SUS 310의 경우 3~237mg/d$m^2$.day, Inconel 600의 경우 4~660mg/d$m^2$.day로 부식속도는 크게 증가되었다. 50$0^{\circ}C$, 석탄가스 분위기에서 부식속도는 SUS 310은 45mg/d$m^2$.day, SUS 316은 110mg/d$m^2$.day, Inconel 600은 576mg/d$m^2$.day, 그리고 Hastelloy X 는 140mg/d$m^2$.day로서 합금강 시편 중 SUS 310 합금강이 가장 우수한 내식성을 나타내었다. 부식 표면에는 황화니켈, 황화철 피막이 형성되었다.

• Journal of Applied Biological Chemistry
• /
• v.63 no.3
• /
• pp.275-282
• /
• 2020

As pesticide safety was extended to agricultural environments and Positive List System was carried out, Pesticide safety management in soils has become even more important. To improve pesticide safety in soils needs the degradation technology of the residues in soils and reduce plant uptake of pesticides. In this study, biochars and quicklime as the degradation methods of pesticides (azoxystrboin, procymidone and tricyclazole) were used to identify the reduction effects. The experimental methods were putting biochars and quicklimes (0, 0.5, 1.0, 2.0% per 15 cm soil weight) in soils and analyzing the pesticide residues at 0, 10, 20, 35, 50 day. To identify the reduction effects of uptake from soil to korean cabbages (roots, leave, stems) by biochar treatment, the residues in samples were analyzed. As a results, azoxystrobin (36-96%), procymidone (40-117%) and tricyclazole (26-83%) were reduced in soils when treated with 2.0% quicklime (p<0.05). There were no reduction effect in soils when treated with 1.0% or less biochar. However, the amounts of residues translocated to roots (0.11-1.62 mg/kg), leave (0.05-0.29 mg/kg), stems (0.06-0.1 mg/kg) were reduced treated with 2.0% biochar treatments. The biochar and quicklime can be applicable to agricultural field to improve pesticide safety in soils.

• Safety and Health at Work
• /
• v.1 no.2
• /
• pp.192-200
• /
• 2010

Objectives: We have investigated the toxic effects of the inhalation of subchronic and acute levels of n-octane. Methods: The rats were exposed to n-octane of 0, 2.34, 11.68 and 23.36 mg/L (n = 5 rats/group/gender) in an acute inhalation test (Organization for Economic Co-operation and Development (OECD) TG 403), or to 0, 0.93, 2.62 and 7.48 mg/L (n = 10 rats/group/gender) for a subchronic inhalation test (OECE TG 413), to establish a national chemical management system consistent with the Globally Harmonized Classification System (GHS). Results: Acutely-exposed rats became lethargic but recovered following discontinuation of inhalation. Other clinical symptoms such as change of body weight and autopsy finds were absent. The LC50 for the acute inhalation toxicity of n-octane was determined to exceed 23.36 mg/L and the GHS category was 'not grouping'. Subchronically-treated rats displayed no significant clinical and histopathological differences from untreated controls; also, target organs were affected hematologically, biochemically and pathologically. Therefore, the no observable adverse effect level was indicated as exceeding 7.48 mg/L and the GHS category was 'not grouping' for the specific target organ toxicity upon repeated exposure. Conclusion: However, n-octane exposure should be controlled to be below the American Conference of Industrial Hygienists recommendation (300 ppm) to prevent inhalation-related adverse health effects of workers.

• Toxicological Research
• /
• v.20 no.2
• /
• pp.159-166
• /
• 2004

Safety pharmacological properties of CJ-11555, an anti-cirrhotic agent, were investigated in experimental animals and in vitro test system. CJ-11555 had no effects on normal body temperature in rats, motor coordination, chemoshock induced by pentetrazol, electric shock induced by electric shocker and writhing syndromes in mice at dose levels of 100, 300 and 1,000 mg/kg. CJ-11555 inhibited intestinal activity and prolonged hexobarbital-induced sleeping time in mice at the dose level of 1,000 mg/kg. CJ-11555 affected on general activity and behaviour tests in SD rats, such as lacrimation, ptosis, piloerection, decreased body tone, abnormal dispersion within the cage, diarrhoea, red colored faeces, slight hypothermia and decreased grooming, at the dose level of 1,000 mg/kg in rats. CJ-11555 was effected on cardiovascular and respiratory system in anesthetized beagle dogs, such as tachycardia, increase of mean blood pressure and decrease of PR interval, decrease of respiratory rate and minute volume, at dose levels of 10 and 30 mg/kg. However, these effects were also observed in vehicle treated anesthetized beagle dogs. In in vitro experiments, CJ-11555 inhibited agonists (histamine, acetyl-choline or $BaCl_2$) induced contraction of isolated guinea-pig at the concentration of 30$\times$$10^6$ M. CJ-11555 was weekly inhibited hERG channel current at concentrations of 10 and 30$\times$$10^6$ M, and $IC_{50}$ was estimated to be higher than 30${\times}$$10^6$M. Based on these results, it was concluded that CJ-11555 affected on cardiovascular and respiratory system, general activity and behaviour and hexobarbital-induced sleeping time at the dose level of 1,000 mg/kg and contraction of the smooth muscle and hERG channel current at the concentration of 30$\times$$10^6$ M.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.21 no.2
• /
• pp.82-89
• /
• 2011

Methylcyclohexane is frequently used in industrial sites (2,592tons/year) as rubber adhesives, ink, paint thinners, organic solvents, and so on. However, there are limited data on the toxic evaluation of methylcyclohexane. This study aims to predict the hazards and neurological effects of methylcyclohexane using SD rats in order to prevent health disorders of workers. The OECD Guideline for Testing of Chemicals (OECD, 2001) was used as a reference during the tests. For 13 weeks (once a day, five days per week) 0, 10, 100 and 1,000mg/kg/day of methylcyclohexane was injected to SD rats to observe any changes in the body or organ weight, hematology, histopathology, mobility, blood pressure, and neurotransmitter. As a result, some male and female SD rats injected with 1,000mg/kg/day of methylcyclohexane died. On the other hand, surviving rats showed significant changes such as hematological changes involving the decrease in the number of red blood corpuscles, and the decrease or increase in the weight of the lungs, kidneys, spleens, and livers (p< 0.05, p<0.01). Also histopathological lesions were observed in the hearts and kidneys. In the test for the effect on the nervous system, SD rats injected with 100mg/kg/day of methylcyclohexane had higher blood pressure levels compared to the control group. However, no abnormal effects was observed in the mobility, serotonin, neurotransmitter, and the biopsy of the brain and coronary arteries. The study results revealed that the livers, hearts, and kidneys were affected by methylcyclohexane. The absolute toxic dose of methylcyclohexane is 1,000mg/kg/day, NOAEL is 100 mg/kg/day, and it is not a toxic substance to the nervous system.

• Journal of the Korean Society of Safety
• /
• v.21 no.1 s.73
• /
• pp.65-71
• /
• 2006

Flame retardancy and mechanical properties of polyolefinic mixed waste plastics/filler composites were investigated by using inorganic flame retardant(magnesium hydroxide) and PUB(polyurethane block) powder generated from cryogenic insulation process. All composites were obtained by extrusion and after compression molding. The effect of PUB powder on the properties of the composites was studied by tensile and izod impact test, morphology studies and flammability as LOI and UL94 vertical burning test and smoke density. The objective of this work is to obtain good mechanical properties from recycled PP composites with $Mg(OH)_{2}/PUB$ powder as fillers and optimum cost-performance balance, in addition to flame retardant characteristics.