국내 광산 종류별 근로자의 유해물질 노출 평가 : 발암성 물질을 중심으로 Focused on Carcinogenie Substanees

신용철,최병순,이병규,이광용,이지태,이종성,이정오,김기웅,고경선,김태균,정호근 한국산업위생학회 2002 한국산업보건학회지 Vol.12 No.2

The objective of this study was to assess mining workers' exposures to potentially carcinogenic air contaminants with major non-carcinogenic contaminants in various types of mines in Korea. The number of mines by type was two coal, one mica ore, one lead/zinc ore, one iron ore, and two limestone mines. The concentrations of air contaminants (total/respirable dust. crystalline silica, chromium, lead, nickel, berillum, cadmium, and fibrous particulate) were determined. The geometric means (GMs) of total dust concentrations at coal, mica, lead/ zinc ore, iron ore and limestone mines were 18.9, 1.82, 1.45, 0.95, and 1.29 ㎎/㎥, respectively, and was significantly different among the kind of mines (p</0.05). Average total dust concentrations in coal mines exceeded the occupational exposure limit for coal dust (5㎎/㎥) established by the Korea Minisry of Labor. The GMs of respirable dust concentration at coal, mica, lead/zinc ore, iron ore, coal and limestone mines were 5.15, 0.48, 0.17, 0.70, and 0.35 ㎎/㎥, respectively, and significantly different among the kind of mines (p<0.05). The GMs of total and respirable crystalline silica concentrations at coal mines were 0.13 ㎎/㎥ and 0.05 ㎎/㎥, respectively, and the values at other mines were below the limit of detection or much lower than those of coal mines. Fibrous particulate in air samples was not detected or <0.01 fibers/cc in all mine. Although the concentrations of carcinogenic metals (Cr(Ⅵ), Cr, Pb, Cd, Ni and Be) and non-carcinogenic metals (Fe and Cu) were below the exposure limits in all mines, but the carcinogenic metals were detected at relatively high levels in air samples from coal iron and limestone mines. It was found that the miniers of all the mines were exposed at lower levels to mixture of potential carcinogens and that particularly the coal miners would have the higher risks of cancer with pneumoconiosis.

조선업의 도장 작업시 취급하는 도료중 유해물질 성분에 관한 연구

신용철,이광용 한국산업위생학회 1999 한국산업보건학회지 Vol.9 No.1

Potential chemical hazards encountered in painting operation of four shipyards and a ship-repair shop were investigated through the material safety data sheets (MSDS). Material safety data sheets (MSDS) for 307 paints, 50 thinners and 34 binders were collected and reviewed. It was shown that various organic solvents such as aromatic hydrocarbons, aliphatic hydrocarbons, ketones, alcohols, glycols, glycol ether acetates and esters were contained in painting materials. Of these solvents, xylene was found in the largest number of painting materials. sixty percent of the thinners contained xylene in the contents of 20-100%. Other most frequently found solvents were 1-methoxypropanol, 1-methoxypropyl acetate, n-butanol, methyl isobutyl ketone, toluene, isopropanol, and n-butyl acetate, etc. Glycol ethers such as 2-methoxyethanol (2-ME), 2-methoxyethyl acetate (2-MEA), 2-ethoxyethanol (2-EE), 2-ethoxyethyl acetate (2-EEA) and 2-butoxyethanol (2-BA) were regarded as having the potential to cause adverse reproductive effects, embryotoxic effect and hematotoxic effects, and were found in some epoxy panting materials. Coal tar pitch was included in some paints(13%) where polynuclear aromatic hydrocarbons (PAHs) could be contaminated. Inorganic pigments such as lead chromate and zinc potassium chromate were found in some paints (8%). The epoxy resin based paints, which may contain isocyanates such as toluene diisocyanates and hexamethylene diisocyanates causing potential sensitization and asthma to upper respiratory organ, were mostly used in the shipyards. The constituents in the MSDS were significantly different from the results analyzed using gas chromatography/mass detector: minor constituents or impurities were omitted in many MSDS. In conclusion, xylene was the most frequent organic solvent in painting materials, and glycol ethers, including 2-ME, 2-MEA, 2-EE, 2-EEA and 2-BA, were found some products. Also, painting workers may be exposed to PAHs, lead, chromate, isocyanates, organic tin and other various chemicals. The compositions of chemicals in painting materials were variable significantly, and the hazards were changed. These facts should be considered in environmental monitoring and control of the hazards.

폐암 발생 용접공의 유해물질 노출 평가 및 폐암 원인에 관한 고찰

신용철,박정선,최정근,이나루,이광용,권은혜,정호근,박승현,이용학,유기호 한국산업위생학회 2000 한국산업보건학회지 Vol.10 No.1

The purpose of this case study is to report a case of lung cancer with exposure to welding fumes of welders in Korea and to demonstrate the causal relationship with exposure to welding fumes, especially with nickel and hexavalent chromium. The case is 47 years old, and had been engaged in welding, gas cutting, grinding and goosing on mild, stainless steel and nickel steel for 11 years from 1982 to 1993, and have been engaged in cleaning steel rollers with a cleaning oil in the same work shop since 1993. The level of welding fume exceeded the occupational exposure limit of 5㎎/㎥ established by the Korean Ministry of Labor and American Conference of Government Industrial Hygienists (ACGIH). Especially, detectable hexavalent chromium and nickel was generated during welding, gousing on stainless and nickel steel. However, there was no ventilation systems(local and dilution) and no personal protection. There is several evidence that the past (1983-1993) exposure would be higher than the present. In conclusion, the lung case could be associated with his task including welding, gousing, and this association could be attributed to carcinogenic potential of the nickel and chromium in the fume.

모 조선업체 아크 용접 작업자의 공기중 6가 크롬 및 니켈 노출에 관한 연구

신용철,강성규,오세민,이나루,문영한,이광용,이기라 한국산업위생학회 1998 한국산업보건학회지 Vol.8 No.2

The aim of this study was to evaluate welders' exposure to hexavalent chromium (Cr(VI)) and nickel (Ni) during welding operations in a Korean shipyard. The airborne Cr(VI) and Ni concentrations were measured during metal inert gas (MIG) welding on mild and stainless steel, and manual metal arc (MMA) welding on mild steel. The geometric mean (GM) of Cr(VI) concentrations inside the welding helmet during MIG welding on mild steel were 0.0018 ㎎/㎥ inside a ship section, and 0.0015-0.0026 ㎎/㎥ at the welding shops. All of the personal breathing zone air samples were below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV^ⓡ) of 0.01 ㎎/㎥. Conversely, eighty-eight percent(21 of 24) of the personal breathing zone air samples exceeded the National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit of 0.001 ㎎/㎥. Ni was not detected on 20 of 23 air samples collected during MIG welding on mild steel. The three Ni samples above the limit of detection ranged from 0.015 to 0.044 ㎎/㎥. The GM of Cr(VI) concentrations during MMA welding on mild steel were 0.0013 ㎎/㎥, but Ni was not detected in the air samples during this operation. It is assumed that the airborne Cr(VI) and Ni during mild steel welding were derived from the base metals which contained about 0.03% Cr and 0.03% Ni. The GM of airborne total Cr, Cr(V1) and Ni concentrations during MIG welding on stainless steel were 4.02, 0.13 and 0.86 ㎎/㎥, respectively, and the levels of Cr(VI) and Ni were above the ACGIH-TLV^ⓡ Cr(VI) comprised about 35.5% of the total chromium(Cr) from MIG welding on mild steel, and about 8.4% of total Cr from MIG welding on stainless steel. The ratios of Cr(VI) to total Cr were significantly different among welding shops. It was concluded that welders were exposed to high levels of Cr(VI) and Ni during welding on stainless steel, and were exposed to low levels of Cr(VI) even during welding on mild steel.

Preliminary evaluation of new ⁶⁸Ga-labeled cyclic RGD peptides by PET imaging

Shin, Un Chol,Jung, Ki-Hye,Lee, Ji Woong,Lee, Kyo Chul,Lee, Yong Jin,Park, Ji-Ae,Kim, Jung Young,Kang, Joo Hyun,An, Gwang Il,Ryu, Young Hoon,Choi, Jae Yong,Kim, Kyeong Min Korean Society of Radiopharmaceuticals and Molecul 2016 Journal of radiopharmaceuticals and molecular prob Vol.2 No.2

Integrin ${\alpha}_v{\beta}_3$ plays an important role in the tumor metastases and angiogenesis. Arginine-glycine-aspartate (RGD) peptide motif binds to the integrin ${\alpha}_v{\beta}_3$. General $^{68}Ga$-labeled cyclic RGD peptides was rapidly eliminated from the circulatory system by renal excretion because of its hydrophilic property. The purpose of this study was to develop a novel $^{68}Ga$-labeled cyclic RGD peptides, which could acquire enhanced PET tumor images with improved pharmacokinetics by adopting biphenyl group between chelator and RGD peptides. $^{68}Ga$-DOTA-2P-c(RGDyK) was demonstrated a 12% higher lipophilicity level than $^{68}Ga$-DOTA-c(RGDyK) as a reference compound. In the animal PET, $^{68}Ga$-DOTA-2P-c(RGDyK) represented relatively lower blood-clearance, and an increased signal to noise ratio compared to $^{68}Ga$-DOTA-c(RGDyK). From these perspective, $^{68}Ga$-DOTA-2P-c(RGDyK) could be a good candidate for in integrin ${\alpha}_v{\beta}_3$-expressed tumor imaging.

가정의학과 개원의의 호흡기 감염 환자에 대한 항생제 사용양상

신호철,최윤선,어광수,변재준,이재호,노용균,김철환,일차진료연구망회원 대한가정의학회 2000 Korean Journal of Family Medicine Vol.21 No.7

MRI-Based Multimodal Approach to the Assessment of Clinical Symptom Severity of Obsessive-Compulsive Disorder

Shin-Eui Park,Byeong-Chae Kim,Jong-Chul Yang,Gwang-Woo Jeong 대한신경정신의학회 2020 PSYCHIATRY INVESTIGATION Vol.17 No.8

Objective This study assessed the associations of the abnormal brain activation and functional connectivity (FC) during memory processing and brain volume alteration in conjunction with psychiatric symptom severity in patients with obsessive-compulsive disorder(OCD). Methods Twenty-OCD patients and 20-healthy controls (HC) underwent T1-weighted and functional imaging underlying explicit memory task. Results In memory encoding, OCD patients showed higher activities in right/left (Rt./Lt.) inferior temporal gyrus (ITG), medial prefrontal cortex (MPFC), dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex (ACC), compared with HC. In task-based FC, caudate (Cd) was positively connected with DLPFC and ITG in OCD, while HC showed different connectivities of Cd-ACC and Rt.-Lt. ITG. In memory retrieval, only Cd was activated in OCD patients. Cd was positively connected with DLPFC and vmPFC in OCD, but negatively connected between same brain areas in HC. OCD patients showed increased gray matter (GM) volumes of cerebellum, DLPFC, orbitofrontal cortex (OFC), hippocampus, Cd and ITG, and concurrently, increased white matter volumes of DLPFC. In OCD patients, GM volumes of Cd and OFC were positively correlated with HAMA and Y-BOCS. Functional activity changes of Cd in OCD were positively correlated with Y-BOCS. Conclusion Our findings support to accessing clinical symptom and its severity linked by brain structural deformation and functional abnormality in OCD patients.

Comparative Functional Connectivity of Core Brain Regions between Implicit and Explicit Memory Tasks Underlying Negative Emotion in General Anxiety Disorder

Shin-Eui Park,Yun-Hyeon Kim,Jong-Chul Yang,Gwang-Woo Jeong 대한정신약물학회 2022 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.20 No.2

Objective: To investigate not only differential patterns of functional connectivity of core brain regions between implicit and explicit verbal memory tasks underlying negatively evoked emotional condition, but also correlations of functional connectivity (FC) strength with clinical symptom severity in patients with generalized anxiety disorder (GAD). Methods: Thirteen patients with GAD and 13 healthy controls underwent functional magnetic resonance imaging for memory tasks with negative emotion words. Results: Clinical symptom and its severities of GAD were potentially associated with abnormalities of task-based FC with core brain regions and distinct FC patterns between implicit vs. explicit memory processing in GAD were potentially well discriminated. Outstanding FC in implicit memory task includes positive connections of precentral gyus (PrG) to inferior frontal gyrus and inferior parietal gyrus (IPG), respectively, in encoding period; a positive connection of amygdala (Amg) to globus pallidus as well as a negative connection of Amg to cerebellum in retrieval period. Meanwhile, distinct FC in explicit memory included a positive connection of PrG to inferior temporal gyrus (ITG) in encoding period; a positive connection of the anterior cingulate gyrus to superior frontal gyrus in retrieval period. Especially, there were positive correlation between GAD-7 scores and FC of PrG-IPG (r 2 = 0.324, p = 0.042) in implicit memory encoding, and FC of PrG-ITG (r 2 = 0.378, p = 0.025) in explicit memory encoding. Conclusion: This study clarified differential patterns of brain activation and relevant FC between implicit and explicit verbal memory tasks underlying negative emotional feelings in GAD. These findings will be helpful for an understanding of distinct brain functional mechanisms associated with clinical symptom severities in GAD.

Development of a steering-system model considering viscous friction and its verification

Shin, Min Chul,Kim, Seong Han,Cho, Gwang Hee,Chu, Chong Nam Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>A method to model the column-type electric power steering system considering viscous friction is proposed. In general column-type electric power steering systems, viscous friction occurs in the reducer. However, it is very difficult to predict with respect to modelling because it varies with the conditions, and accordingly many parameters should be considered. In this study, in order to estimate the dynamic behaviour of a column-type electric power steering system which uses a worm gear as a reducer, the viscous friction generated in the worm gear was derived through theoretical approaches, and the results were applied to modelling the steering system. In the theoretical approaches, the gear geometry and Hertz’s law were employed to derive parameters such as the normal load and the sliding velocity from the worm gear’s driving conditions. Then, the derived parameters were applied to a tribometer to measure the friction coefficients between the worm and the worm wheel. Finally, the friction coefficients were converted to the viscous friction torque of the steering system. By applying the converted viscous friction torque to the modelling, the entire steering system was modelled and the results were verified by comparative simulations and experiments. To model the entire steering system, the individual subparts of the steering system such as the steering column, the universal joint and the rack-and-pinion gear were modelled with MATLAB/Simulink. Then, for verification of the steering-system model, the dynamic behaviour of the steering system was measured experimentally and compared with the simulation results. Taking into account viscous friction and all the mechanical characteristics of the steering system, the established steering-system model which considers viscous friction was employed to estimate very accurately the dynamic behaviour of the steering system, whereas use of the steering-system model which does not consider viscous friction did not achieve accurate estimations.</P>

회귀분석에 의한 공기중 인조광물 섬유 허용기준과 부합하는 총분진 농도의 추정

신용철,이광용 한국산업위생학회 1999 한국산업보건학회지 Vol.9 No.2

The purpose of this study was to investigate the correlation between airborne total dust and man-made mineral fibers (MMMF), and to estimate total dust concentration to maintain below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV^ⓡ) for the MMMF. The regression coefficients between airborne total dust concentrations and fiber concentrations determined in the industries producing glass fibers, rock wool, refractory ceramic and continuous filament glass fibers products were 0.41, 0.42, 0.20 and 0.19, respectively. The size characteristics of fibers as well as the amounts of contaminated non-fibrous dusts could affect the correlation intensities. When total dust and fiber exposure data were compared with the occupational exposure limits, there was a large gap between two evaluation results. The regression coefficient between total dust and fiber data was increased (r² = 0.88) in the process of insulation installation generating in the higher levels of glass or rock wool fibers. In this case an estimated total dust concentration of glass wool or rock wool fibers complying with the ACGIH TLV (1 f/㏄$gt; was 1.7 ㎎/㎥ . In conclusion, the total dust and fiber concentrations was highly correlated at the higher exposure levels so that total dust-monitoring data could be used to control simply and economically and to estimate worker's exposure to fibers.