• Journal of Korean society of Dental Hygiene
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• v.16 no.3
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• pp.471-477
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• 2016

Objectives: Fluoride is widely used in the prevention and control of dental caries. The purpose of this study is to examine the biological effects of Sodium fluoride on the proliferation of oral normal cell in vitro(MDPC-23, HaCaT, HGF-1 cells). Methods: The proliferation of normal cells and the cyto-skeletal change of normal cells were assessed by WST-1 assay and F-actin stain assay. The statistical significances of the resulting data were analyzed using SPSS(Window 12.0). Results: The sodium fluoride(0-12 mM) treatment decreased the cell viability in a dose and time dependent manner: HaCaT(6 h): $100{\pm}0$, $98{\pm}0.39$, $82{\pm}2.68$, $75{\pm}0.83$, $69{\pm}1$, $67{\pm}1.42%$(p<0.005); HaCaT(24 h): $100{\pm}0$, $98{\pm}1.85$, $54{\pm}0.64$, $43{\pm}0.4$, $38{\pm}0.32$, $36{\pm}0.13%$(p<0.006), MDPC-23(6 h): $100{\pm}0$, $93{\pm}1.48$, $85{\pm}0.28$, $82{\pm}1.58$, $79{\pm}1.48$, $76{\pm}1.93%$(p<0.009); MDPC-23(24 h): $100{\pm}0$, $91{\pm}1.26$, $58{\pm}0.65$, $49{\pm}1$, $44{\pm}0.74$, $2{\pm}0.05%$(p<0.005), HGF-1(6 h): $100{\pm}0$, $97{\pm}2.93$, $89{\pm}5$, $71{\pm}5.42$, $58{\pm}4.82$, $43{\pm}3.47%$(p<0.009); HGF-1(24 h): $100{\pm}0$, $97{\pm}2.05$, $73{\pm}1.73$, $22{\pm}1.61$, $14{\pm}1.73$, $7{\pm}0.85%$(p<0.005). Thus, changes in cell morphology and disruption of filamentous(F)-actin organization were observed in higher concentration. Conclusions: These results suggest that higher concentrations of fluoride lead to a reduce the number of cells and morphology change of normal cell.

• The Korean Journal of Pharmacology
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• v.18 no.1
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• pp.65-72
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• 1982

It has been known that retinoids are intrinsically of critical importance for control of premalignant epithelial cell differentiation. In the absence of retinoids, normal cellular differentiation and growth does not occur in epithelia such as those of trachea and bronchi. Furthermore, it was also reported that retinoid deficiency enhanced susceptibility to chemical carcinogenesis in the respiratory system, in the bladder, and in the colon of the experimental animal. In 1974, Bollag examined the effects of synthetic retinoids in prevention of development of cancer and demonstrated synthetic retinoids to have more favorable therapeutic index than retinoic acid for causing regression of skin papilloma in mice. Therefore, it was assumed that this anticarcinogenic effect of vitamin A derivatives could be due to modification of the metabolism of the carcinogenic polycyclic hydrocarbon, which must first be activated to exert their effect. Hill and Shih reported that vitamin A compounds and analogs had inhibitory effect on drug metabolizing enzyme from liver and lung tissue of mouse and hamster. Lucy suggested that the chemoprevention effect of vitamin A derivatives is due to reaction with molecular oxygen, and it is possible that inhibition of hydroxybenzpyrene formation is a result of this property. On the other hand, butylated hydroxytoluene which is a potent antioxidant strongly inhibited the formation of mammary tumor induced by dimethylbenranthracene. Also, it was observed that this antioxidant inhibited cancer induction in rats by N-2-fluo-renylacetamide. The purpose of this experiment was to investigate the effect of vitamin A derivatives such as retinoic acid and retinoid on drug-metabolizing enzyme and to determine whether riboflavin tetrabutylate or vitamin E could prevent of modify any changes induced by vitamin A delivatives in the rats. The results obtained were as followings. 1) Body weight was significantly reduced by retinoic acid, but not by retinoid. 2) Retinoic acid markedly increased liver weight while retincid showed no effect on liver weight. Treatment of riboflavin tetrabutylate did not affect retinoic acid-induced change in both body weight and liver weight. 3) Both retinoic acid and retinoid remarkably decreased the activity of aminopyrine demethylase. Pretreatment of riboflavin tetrabutylate, however, prevented inhibitory effect of retinoic acid on the enzyme activity. 4) No significant effect of vitamin E on aminopyrine demethylase was observed in both groups treated with retinoic acid and retinoid.

• Health Policy and Management
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• v.9 no.1
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• pp.30-71
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• 1999

There has been a dramatic increase in public awareness regarding dementia during recent years. However, dementia remains a family affair and patients do not receive adequate care in Korea. This study aims to assist patients and their caregivers by establishing Home and Community based Long-Term Care in a city. The data collected for analysis include five main categories: dementia prevalence, limitations of daily activities of patients, burden of caregivers, the services that patient's family want to utilize, the resources that handle dementia in the community. Major findings can be summarized as follows: 1)The prevalence rate of dementia for elderly people is 13.1 per 100 persons. Alzheimer's disease amount to 38.9% of dementia patients and vascular dementia account for 36.7% of them 2)Eight out of ten patients have mild dementia. Almost all patients have normal ADL. IADL, however, shows different picture. In every items of IADL, about 60% of patients reveals some limitations. 3)The proportion of patients who had medical diagnosis is as low as 20%. Families of patients think dementia as normal aging process and medical doctors in the community do not give special concern to dementia patients. 4)Caregivers does not have proper social support. They suffer from long care time, experience large obstacles in respect of health, daily living, and social activity. 5)Health center and Community welfare center have launched some programs-consultation, home-visiting nursing, day care center, voluntary force mobilization and so on-for dementia patients. But they do not perform expected roles and functions because of lack of skilled personnels and inadequate coordination of relevant organizations for dementia care. 6)Families of dementia patients prefer home helper and home-visiting nurse to hospitalization. For the future, however, demand for institution-based long-term services will increase. We develope community dementia care model based on above findings as follows: 1)Health center execute community cardiovascular control program for the prevention of vascular dementia. 2)Refer to epidemiologic characteristics of patients and preference of family, the most urgent task for dementia care in this city is to expand and organize Home and Community based Long-Term Care. 3)For the continuous and comprehensive care, care plan for a patient must be prepared. Case management team should be builded to prepare this plan and coordinate relevant resources. 4)Special long-term care unit for dementia will be needed in a near future. This unit should have multiple functions, such as day-care center, short stay facility, training center for relevant personnels, besides long-term nursing home considering effective care of dementia and efficient operation of the facility. 5)Voluntary workers deserve their due efforts. Incentive mechanisms must be developed to activate voluntary activities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.559-568
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• 2018

This study examined the factors affecting abdominal obesity by sex among the Korean elderly focusing on health and health behavior related factors. The data utilized in this study were derived from the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI-3) conducted from January to December 2015 by the Korea Centers for Disease Control and Prevention. The subjects of this study were 599 men and 793 women over the age of 65 for whom their waist circumference was known. The data were analyzed by a complex sampling design method applying weights using the SPSS 23.0 program. Korean elderly showed significant differences in demographic factors, health-related factors, and health behaviors according to gender. The abdominal obesity rate of elderly males was 38.3%, while that of elderly females was 50.5%. Among the factors related to health and health behavior, frequency of binge drinking among elderly male and subjective health status of elderly females were significant factors influencing abdominal obesity. Therefore, programs for abdominal obesity management of elderly Koreans should be planned with consideration of differences in health related factors and health behavior and influencing factors by sex.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.3
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• pp.215-226
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• 2015

In this study, with variables the cross section area ($97m^2$, $58m^2$, $38m^2$) and the wind velocity(0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 m/s), the time of getting off train dependent on the way of itself and the width of the evacuation route was analyzed, and also fire and evacuation characteristics is reviewed by cross section area of each wind velocity. As the result, if cross section become smaller, the density of harmful gases in the tunnel increased more than the ratio of decreasing cross section area. In the case of small cross sectional area, the surrounding environment from initial fire is indicated to exceed the limit criteria suggested in performance based design. In the analysis of effective evacuation time for evacuation characteristics, the effective evacuation time was the shortest in the case of evaluating effective evacuation time by the visibility. Also, there was significant difference between the effective evacuation time on the basis of performance based evaluation and the effective evacuation time obtained by analyzing FED (Fractional effective dose), one of the analysis method obtaining the point that deaths occur, against harmful gases.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.887-895
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• 2019

Recently, the number of underground road development projects has been increasing to solve traffic problems in the national capital region and metropolitan areas with intensified overcrowding, and there has been a tendency to plan underground roads by applying a double-deck tunnel technology that has advantages in constructability and economical efficiency. The double-deck tunnel has a structure where one excavation section is divided into two parts and used as up and down lines, and is mainly used as a road for small vehicles only due to its low floor height. In addition, due to the small cross-sectional area, it has characteristics different from those of general road tunnels in terms of ventilation and disaster prevention. In this regard, this study proposed an operational plan that applies an oversized exhaust system, which is one of semi-transverse ventilation systems, to small cross-sectional tunnels like double-deck tunnel with low floor height, and a comparative analysis between smoke exhaust characteristics according to the fire occurrence locations and oversized exhaust systems was conducted using the Fire Dynamics Simulator (FDS). The results showed that unlike uniform exhaust, intensive smoke exhaust using the oversized exhaust port maximized the delay effect of smoke diffusion and limited the smoke within 50 m above and below the fire point.

• Microbiology and Biotechnology Letters
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• v.35 no.1
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• pp.66-72
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• 2007

Yam has been recognized as healthy food due to its various biological activities, such as anti-obesity, antimicrobial, anticancer and immune-stimulation activities. In this study, antibacterial activities of 800 more natural plant extracts against yam-putrefactive psychrotrophic bacterium, Pseudomonas rhodesiae YAM-12, were evaluated to select a natural preservative, which is useful to long-term storage of yam and fresh-cut production. Finally, the clove oil was selected, and applied for the production of yam fresh-cut. The 1% of clove oil treated fresh-cut showed minor color changes during 31 days storage at $4^{\circ}C$ and the microbial growth was not detected. When the artificially contaminated fresh cut by dipping with P. rhodesiae YAM-12 suspension for 3 min was treated 1% clove oil, the microbial growth was identified to $10^4$ CFU/g from $10^3$ CFU/g with minor color changes. Whereas, treatment of sterilized water, or 100 ppm NaOCl into artificially contaminated fresh cut showed severe putrefaction $(10^8\;CFU/g)$ and color changes. Considering the previous reports that clove oil has antimicrobial, antioxidation, and antithrombosis activity, the use of clove oil into the yam fresh cut will provide market safety and consumer acceptability by prevention of microbial putrefaction and its biological activity.

• Journal of Microbiology and Biotechnology
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• v.30 no.8
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• pp.1169-1179
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• 2020

In this study, two soybean genotypes, i.e., aluminum-tolerant Baxi 10 (BX10) and aluminumsensitive Bendi 2 (BD2), were used as plant materials and acidic red soil was used as growth medium. The soil layers from the inside to the outside of the root are: rhizospheric soil after washing (WRH), rhizospheric soil after brushing (BRH) and rhizospheric soil at two sides (SRH), respectively. The rhizosphere bacterial communities were analyzed by high-throughput sequencing of V4 hypervariable regions of 16S rRNA gene amplicons via Illumina MiSeq. The results of alpha diversity analysis showed that the BRH and SRH of BX10 were significantly lower in community richness than that of BD2, while the WRH exhibited no significant difference between BX10 and BD2. Among the three sampling compartments of the same soybean genotype, WRH had the lowest community richness and diversity while showing the highest coverage. Beta diversity analysis results displayed no significant difference for any compartment between the two genotypes, or among the three different sampling compartments for any same soybean genotype. However, the relative abundance of major bacterial taxa, specifically nitrogen-fixing and/or aluminum-tolerant bacteria, was significantly different in the compartments of the BRH and/or SRH at phylum and genus levels, indicating genotype-dependent variations in rhizosphere bacterial communities. Strikingly, as compared with BRH and SRH, the WRH within the same genotype (BX10 or BD2) always had an enrichment effect on rhizosphere bacteria associated with nitrogen fixation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.1
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• pp.36-44
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• 2015

The spatial and temporal distribution of dissolved trace metals has been studied to identify trends in space and time and to evaluate the pollution status in a semi-closed bay (Gohyun bay), Korea. Surface seawater samples were collected over four seasons at 18 stations in the bay between 2003 and 2004 and once at 7 stations around a large shipyard in May 2004. The concentration of Cd, Co, Cu, Ni, Pb, and Zn in seawater in February and May were highly variable in space, showing the higher value relative to other season. Those metals concentrations were decreased from inner-to outer-stations. In around the shipyard, Cu, Pb and Zn showed the higher variability depending on time. Cu and Zn concentrations at the sites around the shipyard had 2 times higher values compared with the average of inner stations in Gohyun bay. The very high correlations between salinity and either Cu and Zn has been showed. Especially, there was a significant relationship between Cu and Zn. We recognize that the shipyard is major source of Cu and Zn in seawater. Therefore, marine environment management policy such as the prevention and control of heavy metal input from a shipyard is required.