• Safety and Health at Work
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• v.2 no.3
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• pp.243-249
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• 2011

Objectives: Cement contains hexavalent chromium, which is a human carcinogen. However, its effect on cancer seems inconclusive in epidemiologic studies. The aim of this retrospective cohort study was to elucidate the association between dust exposure in the cement industry and cancer occurrence. Methods: The cohorts consisted of male workers in 6 Portland cement factories in Korea. Study subjects were classified into five groups by job: quarry, production, maintenance, laboratory, and office work. Cancer mortality and incidence in workers were observed from 1992 to 2007 and 1997-2005, respectively. Standardized mortality ratios and standardized incidence ratios were calculated according to the five job classifications. Results: There was an increased standardized incidence ratio for stomach cancer of 1.56 (27/17.36, 95% confidence interval: 1.02-2.26) in production workers. The standardized mortality ratio for lung cancer increased in production workers. However, was not statistically significant. Conclusion: Our result suggests a potential association between cement exposure and stomach cancer. Hexavalent chromium contained in cement might be a causative carcinogen.

• Therapeutic Science for Rehabilitation
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• v.6 no.2
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• pp.59-70
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• 2017

Objective: It is important to assess the participation and understand the characteristics of participation for setting goal of the child's treatment and strengthening participation. In this study, we verified the validity of the LIFE-H 1.0, so that domestic occupational therapists can systematically evaluate children's participation. Methods: This study was conducted for about 2 months from February to April 2016 in 47 children with disabilities and non-disabled children. We divided the children into two groups aged 0-4 years and 5-13 years old and conducted a self-report questionnaire to parents. The collected data were verified by SPSS(Statistical Package for Social Science) statistical analysis program. Results: There was no difference between the two groups in general characteristics. In comparison of two groups, a significant difference(p<.05) was found in the LIFE-H 1.0 total performance and satisfaction score and the high discriminant validity was verified. Conclusion: The ultimate goal of occupational therapy is to increase participation. Therefore, the occupational therapist must be able to assess the level of participation and than set the goal of intervention. This study confirms the high level of validity and expects that Korean version of LIFE-H 1.0 will be widely used in clinical field and research.

• Therapeutic Science for Rehabilitation
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• v.7 no.4
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• pp.67-77
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• 2018

Objective: The purpose of this study was to examine the effects of an occupational therapy intervention program of arts and crafts on the activities of daily living and quality of life of outpatients after a stroke. Methods: Using an experimental pretest-posttest control group design, we conducted the following with ten participants diagnosed with stroke: one retest session, 10 intervention sessions, and one posttest session. MMSE-K (Korean version of the Mini-mental State Examination), COPM (Canadian Occupational Performance Measure), and WHOQOL-BREF (The World Health Organization Quality of Life-BREF) scores were obtained before and after the intervention. The results were analyzed using descriptive and nonparametric statistics. Results: As a result of comparing the pretest-posttest scores of the experimental and control groups, there was no significant difference in K-MBI score improvement in terms of activities of daily living. There was a significant difference in COPM scores between the experimental and control groups. There was a significant difference between the WHOQUP-BREF scores of the experimental group before and after the experiment, as well as between the groups. Conclusions: The results suggest that an arts and craft group occupational therapy intervention program for stroke patients may have a positive impact on activities of daily living and quality of life. Although an arts and craft group occupational therapy intervention program appears to be a promising approach, further studies are required to confirm these findings.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.3
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• pp.235-244
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• 2007

By comparing the proteins from the workers exposed to styrene with the ones from controls, it may be possible to identify proteins that play a role in the occurrence and progress of occupational disease and thus to study the molecular mechanisms of occupational disease. In order to find the biomarkers for assessing the styrene effects early, before clinical symptoms develop and to understand the mechanisms of adverse health effects, we surveyed 134 employees, among whom 52 workers(30 male and 22 female) were chronically exposed to styrene in 10 glass-reinforced plastic boat manufacturing factories in Korea and 82 controls had never been occupationally exposed to hazardous chemicals including styrene. The age and drinking habits and serum biochemistry such as total protein, BUN and serum creatinine in both groups were significantly different. Exposed workers were divided into three groups according to exposure levels of styrene(G1, below 1/2 TLV; G2, 1/2 TLV to TLV; G3, above TLV). The mean concentration of airborne styrene in G1 group was $10.93{\pm}11.33ppm$, and those of urinary mandelic acid(MA) and phenylglyoxylic acid(PGA) were $0.17{\pm}0.21$ and $0.13{\pm}0.11g/g$ creatinine, respectively. The mean concentration of airborne styrene in G2 and G3 groups were $47.54{\pm}22.43$ and $65.33{\pm}33.47ppm$, respectively, and levels of urinary metabolites such as MA and PGA increased considerably as expected with the increase in exposure level of styrene. The airborne styrene concentration were significantly correlated to the urinary concentration of MA(r=0.784, p=0.000) and PGA(r=0.626, p<0.001). In the 2D electrophoresis, the concentration of five proteins including complement C3 precursor, alpha-1-antitrypsin(AAT), vitamin D binding protein precursor(DBP), alpha-1-B-glycoprotein(A1BG) and inter alpha trypsin inhibitor(ITI) heavy chain-related protein were significantly altered in workers exposed to styrene compared with controls. While expression of complement C3 precursor and AAT increased by exposure to styrene, expression of DBP, A1BG and ITI heavy chain-related protein decreased. These results suggest that the exposure of styrene might affects levels of plasma proteinase, carriers of endogenous substances and immune system. In particular, increasing of AAT with the increase in exposure level of styrene can explain the tissue damage and inflammation by the imbalance of proteinase/antiproteinase and decrease of DBP, A1BG and ITI heavy chain-related protein in workers exposed to styrene is associated with dysfunction and/or declination in immune system and signal transduction

• Safety and Health at Work
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• v.13 no.4
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• pp.493-499
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• 2022

Background: The purpose of this study is to construct a job-exposure matrix for lead that accounts for industry and work processes within industries using a nationwide exposure database. Methods: We used the work environment measurement data (WEMD) of lead monitored nationwide from 2015 to 2016. Industrial hygienists standardized the work process codes in the database to 37 standard process and extracted key index words for each process. A total of 37 standardized process codes were allocated to each measurement based on an automated key word search based on the degree of agreement between the measurement information and the standard process index. Summary statistics, including the arithmetic mean, geometric mean, and 95th percentile level (X95), was calculated according to industry, process, and industry process. Using statistical parameters of contrast and precision, we compared the similarity of exposure groups by industry, process, and industry process. Results: The exposure intensity of lead was estimated for 583 exposure groups combined with 128 industry and 35 process. The X95 value of the "casting" process of the "manufacture of basic precious and non-ferrous metals" industry was 53.29 ㎍/m³, exceeding the occupational exposure limit of 50 ㎍/m³. Regardless of the limitation of the minimum number of samples in the exposure group, higher contrast was observed when the exposure groups were by industry process than by industry or process. Conclusion: We evaluated the exposure intensities of lead by combination of industry and process. The results will be helpful in determining more accurate information regarding exposure in lead-related epidemiological studies.

• The Journal of Korean society of community based occupational therapy
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• v.2 no.2
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• pp.25-35
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• 2012

Objective : The purpose of this study was to investigate the effect of virtual reality program on fall efficacy and activities of daily living(ADL) for patients with stroke. Method : Twenty stroke patients were participated voluntarily and were assigned randomly into the control and the experimental groups. Both control and experimental groups were given same basic rehabilitation treatment while only the experimental group was given virtual reality program. The fall efficacy of both groups was assessed using fall efficacy scale(FES) and ADL performance ability was assessed by functional independence measure(FIM). Result : Fall efficacy and ADL performance ability showed a statistically meaningful difference for both experimental and control groups(p< .05), the fall efficacy and ADL performance ability of the experimental group improved meaningfully in a statistical way than that of the control group(p<. 05). Conclusion : It was found that carrying out virtual reality program with occupational therapy has an effect on fall efficacy and ADL performance ability of patients with stroke. Therefore, virtual reality program can be a way of treatment for patients with stroke to improve their fall efficacy and ADL performance ability, and the program can also be applied in clinics as well as occupational therapy.

• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.126-132
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• 2009

The usage and types of chemicals are advancing, specializing, large-scaled increasing, and new chemical exposed workers are concerning to occupational disease. The generation of reactive oxygen in the body from carcinogen, mutation and DNA damage in cancer is protected by natural antioxidants (phytochemicals) with antimutagenic effect. There were many reports of ginsenoside Rb$_1$, Rg$_1$ grievances of the genetic mutation to suppress the effect confirm the genetic toxicity test with chromosomal aberration test and the Comet (SCGE) assay confirmed the suppression effect occurring chromosomal DNA damage. We had wanted to evaluate the compatibility and sensitivity between the chromosomal aberration (CA) test and the Comet assay. We used the CA test and Comet assay to evaluate the anti-genotoxicity of ginsenoside Rb$_1$ and Rg$_1$, in CHO-K1 (Chinese hamster ovary fibroblast) cell in vitro, composed negative control (solvent), positive control (benzo[a]pyrene), test group (carcinogen+variety concentration of ginsenoside) group. The positive control was benzo[a]pyrene (50 $\mu$M), well-known carcinogen, and the negative control was the 1 % DMSO solvent. The test group was a variety concentration of ginsenoside Rb$_1$, Rg$_1$ with 10$^{-8}$%, 10$^{-6}$%, 10$^{-4}$%, 10$^{-2}$%, 1%, 10%. In chromo-somal aberration test, we measured the number of cells with abnormally structured chromosome. In Comet assay, the Olive tail moment (OTM) and Tail length (TL) values were measured. The ratio of cell proliferation was increased 8.3% in 10$^{-8}$%, 10$^{-6}$%, 10$^{-4}$%, 10$^{-2}$%, 1%, 10% Rb$_1$ treated groups, and increased 10.4% in 10$^{-10}$%, 10$^{-8}$%, 10$^{-6}$%, 10$^{-4}$%, 10$^{-2}$%, 1% Rg$_1$ treated groups. In the CA test, the number of chromosomal aberration was decreased all the Rb$_1$ and Rg$_1$ treated groups. In the Comet assay, the OTM values were decreased in all the Rb$_1$ and Rg$_1$ treated groups. To evaluate the compatibility between CA and Comet assay, we compared the reducing ratio of chromosomal abnormalities with its OTM values, it was identified the antimutagenicity of ginsenoside, but it was more sensitive the CA test than the Comet assay. Ginsenoside Rb$_1$ and Rg$_1$ significantly decrease the number of cells with chromosomal aberration, and decrease the extent of DNA migration. Therefore, ginsenoside Rb$_1$, Rg$_1$ are thought as an antioxidant phytochemicals to protect mutagenicity. The in vitro Comet assay seems to be less sensitive than the in vitro chromosomal aberration test.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.338-344
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• 1990

This study investigated the symptoms, medical and occupational history of 424 workers of 5 reactive dye Industries in the Inchon area in Korea. The study was performed on March 6 and July 19, 1989. The tests applied to the subjects were : serum total IgE, specific IgE, skin prick test with 7 inhalatory antigens, pulmonary function test, chest X-ray, methacholine test, and bronchoprovocation test. The workers were classified according to these tests into 4 groups (healthy, realtively healthy, need careful medical observation, and occupational asthma), and were compared in terms of the group characteristics and the symptom prevalence. The prevalece of occupational asthma of workers in reactive dye was 5.9% Significant differences were observed among the 4 groups. The groups were significantly different in the variables of sex and duration of smoking among their general characteristics ; and dyspnea, wheezing, chest pain, cough, nasal symptoms and sore throat among symptoms ; asthma, bronchitis, and other respiratory diseases with respect to their past medical history. This study suggests that we should pay special attention to the workers exposed to the risk of occupational asthma.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.2
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• pp.50-56
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• 2013

Objectives: The present study investigated cytotoxicity and DNA damage in human lung cells in vitro. Methods: Neodymium oxide and lanthanum oxide were dispersed by ultrasonic treatments. The assay was performed with MRC-5 (Human male fetus lung cell). Cytotoxicity and comet assay of lanthanum oxide and neodymium oxide were measured after 24 and 48 hours incubation. Results: After 24 hours of exposure to rare earth metals, the cytotoxicities of lanthanum oxide in more than $1{\mu}M$ concentration groups were significantly increased when compared to the control group, but the cytotoxicities of neodymiun oxide in more than $100{\mu}M$ concentration groups were statistically increased. After 48 hours exposure, cytotoxicities of both materials were statistically increased in $100,000{\mu}M$ concentration groups. Olive tail moments of the lanthanum oxide treated group were significantly increased when compared to the control group. Conclusions: The cytotoxicity of lanthanum oxide was higher than that of neodymium oxide. The DNA of MRC-5 cells treated with lanthanum oxide for 48 hours were significantly damaged.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.2
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• pp.81-90
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• 2006

The Strain Index(SI) has been commonly used to evaluate the musculoskeletal disorders(MSDs) of upper extremities. Recently, the American Conference of Governmental Industrial Hygienists(ACGIH) adopted the Threshold Limit Value for hand activity level (HAL TLV) focused on the hand, wrist, and forearm. The MSDs risks of 37 repetitive works conducted at an automobile climate control system manufacturing factory were evaluated using both the HAL TLV and the SI, and the results by two methods were compared. Also, measured repetitive frequencies of upper limbs joint were mesured using electromyogram and electrogoniometer. The evaluation results of the HAL were related with the repetitive frequency data of upper limbs joint by electrogoniometer, and the NPF was related with %MVC of ECU. The evaluation result of HAL TLV was highly related with the SI score(r=0.66, p<0.01). Of total 37 tasks, 25 tasks(67.6%) were exceeded the TLV and 34 tasks(91.9%) exceeded the SI limit. Although there was a high relationship between the HAL TLV and SI score, the HAL TLV underestimated the risk in comparison with the SI. The correlation coefficients(r) between the HAL TLV data and the repetitive frequency of upper limbs joint were 0.45~0.55(p<0.01). The MSD symptoms was significantly different between high risk groups and low risk groups evaluated by HAL TLV(p<0.01), but was not different between two groups by SI. In conclusion, the HAL TLV is a proper tool for repetitive works.