• Journal of Technologic Dentistry
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• v.22 no.1
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• pp.89-112
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• 2000

Although dental laboratory technicians are prone to be exposed to various work-related health hazardous materials such as dusts, chemicals, etc., the prevalence and nature of work-related health problems of them have not been a matter of great concern in the field of occupational health service in Korea. The purpose of the present investigation was to describe a collected profile of subjective health symptoms and their attributable factors in Korean dental laboratory technicians. A questionnaire listing five groups of health symptoms and five health symptom-related factors was mailed to randomly selected 1,900 dental laboratory technicians. Among them, 1,344 dental laboratory technicians filled out the questionnaires and returnde them. Five groups of health symptoms included musculoskeletal symptom, dermal symptoms, respiratory symptoms, eys symptoms, and ear symptoms. Five health symptom-related factors were occupational environment-related health risk factors, work history, health related habits and status, use of personal protective equipment and general characteristics. Detailed parameters of health risk factors were work posture, vibration, and chemical or physical hazards such as dust, fume, vapor, solvent, light, and noise for occupational environment-related factors; work place, area, number of employees, work hours, career, work part, and work load for work history; Broca's index, hours of sleep, eating, smoking, alcohol, exercise, health examination, and self assessed health status for health habits and status; face masks, goggles, and so on for use of personal protective equipment, and; age, sex, marital status, and education for general characteristics. Before the start of main survey, a pilot survey was carried out for validity and reliability tests of the questionnaire. All the data obtained were coded and analyzed with PC/SAS 6.12 program. The prevalence of health symptoms was the highest in musculoskelton (87.3%), and followde by eyes (78.9%), respiratory organs (64.3%), ears (57.8%), and skin (52.2%) in descending order. Statistically significant risk factors by multiple logistic regression analyses were sex, health examination, self assessed health status, and hand/finger posture in musculoskeletal symptoms; sex, self assessed health status, career, acid gas, and hand contact with resin mixture in deraml symptoms; Broka's smoking, exercise, self assessed health status, and face mask in respiratory symptoms; sex, hours of sleep, self assessed health status, work hours, work load, plaster dust, inadequate lighting, and goggle in eys symptoms, and eating, smoking, self assessed health status, and work load in ear symptoms. With the above considerations in mind, prevalence of subjective symptoms among Korean dental laboratory technicians was relatively high, and they were attributable to most of the occupational environment-related factors, work history, use of personal protective equipment, health habits and status, and general characteristics. Particularly, it is suggested that health promotion programs for promoting self- assessed health status and smoking cessation, preventive measures for protection of the female technicians’health, and reducing work load be necessary, since those factors were associated with more than one subjective symptom.

• Journal of the Korean Geographical Society
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• v.49 no.6
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• pp.812-832
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• 2014

We analyzed physical and chemical properties of sediments from 20 subtidal points and 9 beach points to define sedimentary environment between summer and winter of Shindu Marine Protected Area. Means of particle size in summer were generally finer than winter's. There was distinctively spatial pattern that particle sizes became increasingly fine as west direction and apart from beach in summer, but this pattern was not shown in winter. Coarse sediments were prevailed in winter. To explain these patterns, we propose possible two causes which are spatially different water depth condition related with seasonal wave climate or fine sediment input from an estuary located in south of this area during summer rainy season. Contents of exchangeable cations of sediment in summer were shown $Na^+$>$Ca^{2+}$>$Mg^{2+}$>$K^+$ in order, but those of winter were shown $Na^+$>$Mg^{2+}{\fallingdotseq}Ca^{2+}$>$K^+$. Contents of $Na^+$, $Mg^{2+}$, and $K^+$ were related with contents of fine sediment and showed high correlation in each other. These relations were not shown between $Ca^{2+}$ and others. Our results show that there are spatio-temporal unique sedimentary environments between subtidal zone, beach, and dune near Shindu Marine Protected Area. Therefore, we should consider these spatio-temporal patterns for environmentally sound management of Shindu coastal system.

• KSBB Journal
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• v.21 no.4
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• pp.312-316
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• 2006

A optimal condition for the Ginkgo biloba extraction in ethanol and water binary solvent system has been proposed based on concentration of bilobalide and ginkgolide known as having a antimicrobial components in the range 5% to 70% ethanol in water at $80^{\circ}C$. Concentration of bilobalide as a single component of Ginkgo biloba leaves extract is the highest at the 60% ethanol and ginkgolide A and B is highest at 50% ethanol. Antimicrobial effect of Ginkgo biloba leaves extracts on the S. aureus was also examined by disc diffusion test and optical density test. In case of the disc diffusion test, the clean zone diameter was increased from 0.95 cm to 1.70 cm as ethanol concentration increased from 5 to 70%. However, over the 40% of ethanol concentration the antimicrobial effect was almost flat. Based on these results, we propose that the 40% of ethanol and 60% water solvent is most desirable for Ginkgo biloba extract considering vapor pressure problem in concentrating process after extraction. We introduced SEM and TEM to figure out the morphological change on the surface and inside body of S. aureus when Ginkgo biloba leaves extract was treated. After mixed with Ginkgo biloba leaves extract blast like blebs appeared on the surface of S. aureus cells and cell wall was not observed. From the these results, it seems that the Ginkgo biloba leaves extract including bilobalide and ginkgolide A, B prevent cell wall synthesis.

• The Korean Journal of Mycology
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• v.26 no.4 s.87
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• pp.562-573
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• 1998

The symbiotic activities of arbuscular mycorrhizal fungi (AMF) by analyzing spore density, symbiosis intensity and vertical distribution of AMF spores, phytomasses of higher plants such as Calamagrostis epigeios, Imperata cylindrica, Artemisia scoparia, Aster tripolium and Sonchus brachyotus, and physico-chemical properties of soil were determined in the rhizospheres of higher plants in abandoned two coastal reclaimed lands, which were constructed in 12 and 30 years ago, respectively. Vertical distribution of the AMF spores in the rhizospheres of higher plants was restricted within 20 cm depth from soil surface, which would be closely related with vertical distribution of root system, water table and soil aeration. Of vertical distribution of soil properties, W.C., A-P and K concentrations were increased as soil depth was lowered. In the coastal reclaimed lands, symbiotic activities of the AMF such as spore density and symbiotic intensity, were conspicuously stimulated by the increase of soil pH value, organic matter and total nitrogen concentrations, but inhibited by the increase of moisture, available phosphorus and sodium concentrations in the rhizosphere soil. Phosphorus absorption by higher plants growing in the reclaimed lands increased by the rise of symbiotic activities of AMF. Since symbiotic activities of AMF were stimulated with decreasing soil phosphorus concentrations, higher plants associated with AMF absorbed a large amount of phosphorus from the soil is low phosphorus concentrations.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.325-336
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• 2006

Domestic serpentinite is one of the important industrial minerals utilizing in the iron manufacturing company such as POSCO in Korea. Serpentinite is distributed in the Ulsan Fe deposit, Andong, Hongseong-Cheongyang, and Gapyeong areas. This study tries to interpret the relationship among the formation of carbonate rocks, iron mineralization, and serpentinite alteration throughout the study of field occurrence, mineralogy, and chemical compositions. Serpentine is formed by the break-down of olivine and pyroxene of parent peridotite. The serpentinization is inferred to be formed by the hydrothermal fluid derived from intruded Cretaceous granite and the addition of meteoric water. Variation of major oxides such as $SiO_2,\;Fe_2O_3$, and MgO in serpentinized rocks are controlled by the degree of serpentinization and Fe mineralization. Variation of $Al_2O_3$ and CaO contents of altered rocks is dependent on the amount of the residual minerals such as calcite and homblende, and on the degree of chloritization. The presence of carbonate rocks reported in the sedimentary origin or igneous origin (carbonatite) provided a geological environment to form skarn type Fe deposit regardless of its origin. The geological processes of Ulsan Fe deposits are inferred to be formed as the order of the formation of carbonate rocks ${\to}$ the intrusion of Cretaceous granite ${\to}$ serpentinization ${\to}$ Fe mineralization by the interprelation of field occurrence and mineralogical characteristics.

• Journal of the Korean association of regional geographers
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• v.5 no.1
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• pp.121-135
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• 1999

This study investigated the location conditions, spatial linkage structures, and firm specific problems of small firms of the Greater Cincinnati metropolitan area by sectors and by areal distribution. The major locational advantages were closeness to customers and suppliers followed by accessibility to inter-state highways. These results were supported by spatial linkage structures in which within-region linkages occupied a greater portions of linkage, showing the importance of small firms in the regional economy. The linkage patterns showed distance decay effect with high elasticity. While there were no significant differences of locational conditions and spatial linkage structures of small firms between core and peripheral area, a slight difference was identified among sectors. Chemical related manufacturing firms show different locational conditions and spatial linkage structure with weak within-local linkages. The main locational disadvantages were lack of qualified labor, undesirable neighborhood, heavy tax, and space shortage. Considering the biggest problems such as lack of qualified labor, difficulties in sales/marketing, low accessibility to financial resource, and technological inability, the inter-related cooperative business networks among firms and regional institutions, consulting companies, chamber of commerce, and universities are needed to stimulate regional economic development and survival of small firms.

• Applied Microscopy
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• v.40 no.4
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• pp.245-251
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• 2010

In this study, we applied 15% glycolic acid peeling agent and 30% glycolic acid peeling agent to the dorsal skin of mice and analyzed the oil content, moisture content, and pH value of the skin before and after test using cutometer. Ultrastructure for changes in the epidermis of mice were observed under a dermoscope and a scanning electron microscope before and after test. When using 15% glycolic acid peeling agent, the changes of moisture content was measured 74.67 AU for the normal control group and 70.21 AU for the experimental group, the oil content was 13.49 mg/$cm^2$ for the normal control group before test and 8.25 mg/$cm^2$ after test, and the pH value was 6.70 and 5.36 before and after test, respectively. When using 30% glycolic acid peeling agent, the moisture content was measured 74.46 AU for the normal control group before test and 53.50 AU for the experimental group after test, the oil content was 13.82mg/$cm^2$ and 5.70 mg/$cm^2$ before and after test, and the pH value was 6.45 and 4.58 before and after test, respectively. As such, it was found that the changes of moisture and oil content on the skin rely on the concentration of peeling agent and the degree of exfoliation of keratin. The surface of stratum corneum of mice with application of 15% glycolic acid peeling agent was relatively smooth and the exposed cellular surface of keratinocyte had some wrinkles. The surface of stratum corneum of mice with application of 30% glycolic acid peeling agent was smooth. No wrinkles were observed under high-resolution scanning electron microscope.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.3
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• pp.277-285
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• 2016

Objectives: This study was performed in order to evaluate whether 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) could be detected among residents living near Camp Caroll in Waegwan and whether serum concentrations of dioxins, including 2,3,7,8-TCDD, and organochlorine pesticides (OCPs) are associated with length of residence. Methods: Study subjects totaled 113 (for dioxins) and 190 (for OCPs) adults who were selected from participants in a medical investigation. Serum concentrations of dioxins and OCPs were measured using HRGC/HRMS. Information on length of residence was obtained through questionnaires. Results: 2,3,7,8-TCDD was not detected in serum among all subjects. When length of residence was classified as a categorical variable, after adjusting for confounding variables, only residents living in Waegwan for 40 years or longer tended to have high total TEQ values and 2,3,4,7,8-PeCDF with marginal significances. There was no dose-response relation between length of residence and serum concentrations of these chemicals. In multiple regression models with continuous values of the length of residence, total TEQ value and 1,2,3,4,6,7,8-HpCDF were positively associated with length of residence. However, they explained about 3-5% of total variations of serum concentrations of these compounds, while age, consumption of fatty fish, body mass index, alcohol drinking, and cigarette smoking were main variables affecting serum concentrations of dioxins or OCPs. Conclusions: In the current study, high concentrations of certain compounds were mainly observed among persons who lived in Waegwan for at least for 40 years without a dose-response relation. Therefore, it seems difficult to conclude that length of residence meaningfully contributed to the current serum concentrations of dioxins or OCPs among residents in Waegwan. However, considering the half-life of 2,3,7,8-TCDD and indirect exposure routes, the limitations of the current study design should be considered in the interpretation of the study findings.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.359-365
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• 2017

There is greater standardization of quality control for microscopic examination of urine than for physicochemical test. In this study, we investigated whether it is possible to control the sediment accuracy by microscopic examination through the real thing by preserving the essential sediment with glutaraldehyde, which is required for the rationality of sediment quality control. A urine specimen was prepared using 2.5% glutaraldehyde as a preservation solution. Samples treated with urine preservatives confirmed the morphological deformation of the cells for four weeks at intervals of one week and confirmed whether they should be preserved for 4 weeks thereafter. After preparing the required sediment slide, two more slides were produced; one was stored in a refrigerator for, and the other was stored at room temperature. The morphological deformation of the specimen was confirmed. Glutaraldehyde has the effect of preserving the refrigerated essential sediments and storing them for up to 8 weeks, refrigerated storage after slide production, stabilized by 3 days. Moreover, after treatment with preservatives, the production of the slide and comparison between the measured values between the laboratories and examiners showed a low consistency. In conclusion, we showed that the urine sediment components can be preserved, and it can be used for quality control and education through real objects.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.141-147
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• 2000

Interrelation between the antioxidative activity of hot-water extracts of 130 medicinal plants and their cellular antimutagenic activity was investigated. Antioxidative activity was evaluated by assaying electron-donation to DPPH free radical and scavenging of hydroxyl radical $({\cdot}OH)$ generated through Fenton rection, respectively. All medicinal plants examined in this study exhibited markedly electron-donating ability and radical scavenging ability in each assay system. The results demonstrated the fact that Pilbal (Piper longum L.) is the strongest in electron-donating activity, on the other hand, that Seokgok (Dendrobium moniliforme L.) is the strongest in ${\cdot}OH$ scavenging activity. When evaluated their antioxidative activities, 24 medicinal plants including Jimo (Anemarrhena asphodeloides Bunge) were found to be the medicinal plants carrying strong antioxidative activity, which exhibited more than 50% activity compared to the control group in both electron-donating and free radical scavenging. The experiment was also performed to examine whether 11 medicinal plants having significant antimutagenicity damage DNA in the presence of $Cu^{2+}$, showing the fact that all samples tested, except Taeksa (Alisma canaliculatum All. Br.), Paekjain (Nitraria sibirica Pall) and Ohyak (Lindera strychifolia Sieb. et Zucc. Villar) are capable of inducing DNA strand break. We also found that Taeksa and Paekjain strongly block DNA strand break induced by chemical mutagen mitomycin C.