• Journal of Korean Society of Environmental Engineers
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• 제33권7호
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• pp.544-551
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• 2011

The objective of this study was to analyze VIRULO model, a probabilistic quantitative model, which had been developed by US Environmental Protection Agency. The model could assess the viral attenuation capacity of soil as hydrogeologic barrier using Monte Carlo simulation. The governing equations used in the model were composed of unsaturated flow equations and viral transport equations. Among the model parameters, those related to water flow for 11 soil types were from UNDODA data, and those related to 5 virus species were from the literatures. The model compared the attenuation factor with threshold of attenuation to determine the probability of failure and presented the exceedances and Monte Carlo runs as output. The analysis indicated that among 11 USDA soil types, the viral attenuation capacity of loamy sand and sand were far lower than those of clay and silt soils. Also, there were differences in the attenuation in soil among 5 viruses with poliovirus showing the highest attenuation. The viral attenuation capacity of soil decreased sharply with increasing soil water content and increased nonlinearly with increasing soil barrier length. This study indicates that VIRULO model could be considered as a useful screening tool for viral risk assessment in subsurface environment.

• Therapeutic Science for Rehabilitation
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• 제1권2호
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• pp.41-53
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• 2012

Objective : The purpose of the research is to investigate Korean occupational therapists' awareness of Evidence-Based Practice(EBP), basis of clinical decision making, barrier factors of EBP execution. Methods : Form December 2009 to March 2010, 500 questionnaires were sent out to clinical occupational therapists and 160 questionnaire which are returned by the therapists were analyzed through descriptive statistics. Results : There are more female respondents than male. More than 90% of them had less than 5 years experience. Most of respondents hadn't experienced education concerning EBP(76%), and the education is not periodically conducted(55%). Moreover, treatment was being tailored based on subjective judgement. On the other hand, the degree of recognition showed that the professionalism of occupational therapists can be improved through EBP(96%), and be helpful to make clinical decision(88%). Most of the therapists answered that guaranteeing enough time to search the basis of treatment(90%) and participating in the education course(92%) is needed to make EBP applicable. This result shows that while the application rate of EBP is low, the recognition rate of EBP is high, which means it is necessary to revitalize EBP education program. Conclusions : In order to provide quality service, education course and instructor training program is needed. We should also make a great effort to offer evidence-based education to occupational therapy students. Furthermore, EBP has to be carried out to improve the professionalism of occupational therapists, and the research about education program and its effect has to be executed.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제19권6호
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• pp.709-714
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• 2018

This study researched the reasons for changing polarity in accordance with junction properties in an interface of semiconductors. The contact properties of semiconductors are related to the effect of the semiconductor's device. Therefore, it is an important factor for understanding the junction characteristics in the semiconductor to increase the efficiency of devices. For generation of various junction properties, carbon-doped silicon oxide (SiOC) was deposited with various argon (Ar) gas flow rates, and the characteristics of the SiOC was varied based on the polarity in accordance with the Ar gas flows. Tin-doped zinc oxide (ZTO) as the conductor was deposited on the SiOC as an insulator to research the conductivity. The properties of the SiOC were determined from the formation of a depletion layer by the ionization reaction with various Ar gas flow rates due to the plasma energy. Schottky contact was good in the condition of the depletion layer, with a high potential barrier between the silicon (Si) wafer and the SiOC. The rate of ionization reactions increased when increasing the Ar gas flow rate, and then the potential barrier of the depletion layer was also increased owing to deficient ions from electron-hole recombination at the junction. The dielectric properties of the depletion layer changed to the properties of an insulator, which is favorable for Schottky contact. When the ZTO was deposited on the SiOC with Schottky contact, the stability of the ZTO was improved by the ionic recombination at the interface between the SiOC and the ZTO. The conductivity of ZTO/SiOC was also increased on SiOC film with ideal Schottky contact, in spite of the decreasing charge carriers. It increases the demand on the Schottky contact to improve the thin semiconductor device, and this study confirmed a high-performance device owing to Schottky contact in a low current system. Finally, the amount of current increased in the device owing to ideal Schottky contact.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1446-1451
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• 2016

Clostridium difficile toxin A causes acute gut inflammation in animals and humans. It is known to downregulate the tight junctions between colonic epithelial cells, allowing luminal contents to access body tissues and trigger acute immune responses. However, it is not yet known whether this loss of the barrier function is a critical factor in the progression of toxin A-induced pseudomembranous colitis. We previously showed that NADH:quinone oxidoreductase 1 (NQO1) KO (knockout) mice spontaneously display weak gut inflammation and a marked loss of colonic epithelial tight junctions. Moreover, NQO1 KO mice exhibited highly increased inflammatory responses compared with NQO1 WT (wild-type) control mice when subjected to DSS-induced experimental colitis. Here, we tested whether toxin A could also trigger more severe inflammatory responses in NQO1 KO mice compared with NQO1 WT mice. Indeed, our results show that C. difficile toxin A-mediated enteritis is significantly enhanced in NQO1 KO mice compared with NQO1 WT mice. The levels of fluid secretion, villus disruption, and epithelial cell apoptosis were also higher in toxin A-treated NQO1 KO mice compared with WT mice. The previous and present results collectively show that NQO1 is involved in the formation of tight junctions in the small intestine, and that defects in NQO1 enhance C. difficile toxin A-induced acute inflammatory responses, presumably via the loss of epithelial cell tight junctions.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• 제31권1호
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• pp.52-70
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• 2018

Objectives : Atopic dermatitis(AD) and environmental factors are closely related, but there is lack of oriental medical examination. So we compared the relationship between AD and various environmental factors in Oriental medicine and Western medicine. Methods : We described the relationship between AD and environmental factors through the latest papers and a review of the oriental medicine literature. Results : The regional diversity of AD incidence implies a close relationship between climate factors and AD, and high altitude and low pH springs also have an effect on AD. Air pollutants from industrialization and urbanization aggravate AD. The increase in indoor residence time and the increase in room temperature and humidity have also increased the sensitization to allergens such as house dust mite. In oriental medicine, wind(風) is one of the environmental factors and is an inflammatory state due to external irritation. Wind-Humidity(風濕) refers to erythematous wetting dermatitis with itching and exudation, Wind-Fever(風熱) refers to acute inflammatory reaction with erythematous papules and plague, and Blood-Weakness(血虛) refers to aggravation and chronicization of inflammation due to persistence of skin barrier impairment. Conclusions : We examined the relationship between AD and various environmental factors. We also described the oriental medical viewpoints of the environmental factors in the occurrence of AD and skin barrier impairment.

• Journal of Applied Biological Chemistry
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• 제64권2호
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• pp.185-192
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• 2021

Psoriasis is a chronic intractable skin disease caused by various inflammatory cytokines such as IL-6, CXCL8, TNF-α, and IFN-γ, as well as IL-17A secreted from Th17 cells and is characterized by hyperkeratosis and chronic inflammation of the epidermis. Brazilin, an active ingredient of Caesalpinia sappan L., is known to exert antioxidant and anti-inflammatory activity, and function in skin barrier improvement. In particular, it was shown as a potential material for treating psoriasis in a tumor necrosis factor (TNF)-α-stimulated HaCaT keratinocyte model. However, the direct regulation of the C-C motif chemokine ligand (CCL) 20, a psoriasis-inducing factor, by brazilin has not been reported. Therefore, in this study, we investigated the suppression of CCL20 and the regulatory mechanism by brazilin using a psoriasis-like model. First, brazilin downregulated CCL20 and CXCL8 in IL-17A-stimulated HaCaT cells in a concentration-dependent manner by inhibiting signal transducer and transcription (STAT)3 phosphorylation. In addition, brazilin significantly inhibited the expression of psoriasis-related genes CXCL8, CCL20, IL-1, IL-6, and TNF-α in TNF-α/IL-17A/IFN-γ-stimulated HaCaT cells. Moreover, brazilin also had a positive effect on improving the skin barrier in TNF-α/IL-17A/IFN-γ-stimulated HaCaT cells. The above results indicated that brazilin ultimately downregulated CCL20 expression by inhibiting STAT3 phosphorylation, and also suppressed the expression of psoriasis-induced cytokines. If the efficacy of brazilin in improving psoriasis is verified through animal models and clinical trials in the future, it may represent a potentially therapeutic substance for psoriasis patients.

• The Journal of Engineering Geology
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• 제23권1호
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• pp.57-65
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• 2013

We developed a computer program (CDFlow v. 1.0) to design countermeasures against debris flows in natural terrain. The program can predict the probability of landslides occurring in natural terrain and can estimate the zone of damage caused by a debris flow. It can also be used to design the location and size of countermeasures against the debris flow. The program is run using the ArcGIS Engine, which is one of the most well-known Geographic Information System (GIS) tools for developers. The quasi-dynamic wetness index and the infinite slope stability equation were applied to predict landslide probability as a type of slope safety factor. The calculated safety factor was compared with the required safety factor, and areas of high probable potential for landslides were then selected and represented on the digital map. The volume of debris flow was estimated using these areas of high probable potential for landslides and soil depth. The accumulated volume of debris flow can be calculated along the flow channel. To assess the accuracy of the program, it was applied to a real landslide site at Deoksan-ri, Inje-gun, Kangwon-Province, where four debris barriers have been installed in the watershed of the site. The results of soil tests and a field survey indicate that the program has great potential for estimating probable landslide areas and the trajectory of debris flows. Calculation of the capacity volume of existing debris barriers revealed that they had insufficient capacity to store the calculated amount of debris flow. Therefore, this program enables a rational estimation of the optimal location and size of debris barriers.

• Journal of Periodontal and Implant Science
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• 제49권5호
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• pp.270-286
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• 2019

Purpose: Despite the well-known anti-inflammatory effects of vitamin D in periodontal health, its mechanism has not been fully elucidated. In the present study, the effect of vitamin D on strengthening E-cadherin junctions (ECJs) was explored in human gingival keratinocytes (HGKs). ECJs are the major type of intercellular junction within the junctional epithelium, where loose intercellular junctions develop and microbial invasion primarily occurs. Methods: HOK-16B cells, an immortalized normal human gingival cell line, were used for the study. To mimic the inflammatory environment, cells were treated with tumor necrosis factor-alpha ($TNF-{\alpha}$). Matrix metalloproteinases (MMPs) in the culture medium were assessed by an MMP antibody microarray and gelatin zymography. The expression of various molecules was investigated using western blotting. The extent of ECJ development was evaluated by comparing the average relative extent of the ECJs around the periphery of each cell after immunocytochemical E-cadherin staining. Vitamin D receptor (VDR) expression was examined via immunohistochemical analysis. Results: $TNF-{\alpha}$ downregulated the development of the ECJs of the HGKs. Dissociation of the ECJs by $TNF-{\alpha}$ was accompanied by the upregulation of MMP-9 production and suppressed by a specific MMP-9 inhibitor, Bay 11-7082. Exogenous MMP-9 decreased the development of ECJs. Vitamin D reduced the production of MMP-9 and attenuated the breakdown of ECJs in the HGKs treated with $TNF-{\alpha}$. In addition, vitamin D downregulated $TNF-{\alpha}$-induced nuclear factor kappa B ($NF-{\kappa}B$) signaling in the HGKs. VDR was expressed in the gingival epithelium, including the junctional epithelium. Conclusions: These results suggest that vitamin D may avert $TNF-{\alpha}$-induced downregulation of the development of ECJs in HGKs by decreasing the production of MMP-9, which was upregulated by $TNF-{\alpha}$. Vitamin D may reinforce ECJs by downregulating $NF-{\kappa}B$ signaling, which is upregulated by $TNF-{\alpha}$. Strengthening the epithelial barrier may be a way for vitamin D to protect the periodontium from bacterial invasion.

• Korean Journal of Agricultural and Forest Meteorology
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• 제23권4호
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• pp.283-294
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• 2021

Solar radiation is an important meteorological factor in the agricultural sector. The ground exposed to sunlight is highly influenced by the surrounding terrains especially in South Korea where the topology is complex. The solar radiation on an inclined surface is estimated using a solar irradiance correction factor for the slope of the terrain along with the solar radiation on a horizontal surface. However, such an estimation method assumes that there is no barrier in surroundings, which blocks sunlight from the sky. This would result in errors in estimation of solar radiation because the effect of shading caused by the surrounding terrain has not been taken into account sufficiently. In this study, the shading effect was simulated to obtain the brightness value (BV), which was used as a correction factor. The shaded relief images, which were generated using a 30m-resolution digital elevation model (DEM), were used to derive the BVs. These images were also prepared using the position of the sun and the relief of the terrain as inputs. The gridded data where the variation of direct solar radiation was quantified as brightness were obtained. The value of cells in the gridded data ranged from 0 (the darkest value) to 255 (the brightest value). The BV analysis was performed using meteorological observation data at 22 stations installed in study area. The observed insolation was compared with the BV of each point under clear and cloudless condition. It was found that brightness values were significantly correlated with the solar radiation, which confirmed that shading due to terrain could explain the variation in direct solar radiation. Further studies are needed to accurately estimate detailed solar radiation using shaded relief images and brightness values.

• Journal of the Society of Cosmetic Scientists of Korea
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• 제48권2호
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• pp.169-180
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• 2022

Streptococcus sp. is generally known as a strain that produces hyaluronic acid. In this study, we focused on ingredients other than hyaluronic acid among several metabolites produced by Streptococcus sp. during cultivation. The hair experimental sample (HAIRCLE^TM) was prepared with Streptococcus sp. culture filtrate under the condition that hyaluronic acid was not produced and the effect on the hair was identified. Tensile strength of hair was tested with a universal testing machine (UTM). Surface properties of a hair were examined with an atomic force microscope (AFM). Our results suggest that HAIRCLE^TM could prevent damage to a hair such as destroyed-cuticle, increased-faction force, and broken-hair. Furthermore, hair-related experiments confirmed that HAIRCLE^TM could promote the expression of hair growth factors VEGF, HGF, and Wnt10b and mitigate male hair loss by inhibiting androgen receptors and TGF-β2 expression. In addition, it was confirmed that the expression of barrier-related factors (INV, CLDN-1) was increased for oxidative stress, and the COX-2 expression, an inflammatory factor, was inhibited, thereby improving damaged scalp barriers and alleviating induced inflammation.