• The Journal of Korean Academy of Prosthodontics
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• v.29 no.2
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• pp.285-294
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• 1991

The human temporomandibular joint as a ginglymoarthrodial one has much in common with the other synovial joints of the body, but it does possess an unique charachteristic in that it must accomodate the various occlusal relations of dentition during an end point of closure. For that reason, the movement of the condyle in the temporomandibular joint is susceptible to influences from the nature of occlusion. Undue loading to the temporomandibular joint can be applied on the occasion of premature contacts in centric relation, balancing side interferences, change of occlusal surfaces due to excessive attrition, loss of tooth. Such occlusal disharmonies in association with the systemic and emotional factors may give rise to the temporomandibular disorder. On the other hand, the changes of occlusal patterns in the growing body can also have an effect on the growth of the temporomandibular joint through the alterations of functional stresses. The purpose of this study was to observe histopathologic response of the temporomandibular joint in unilateral chewing on one side exclusively for 10 months. Three dogs showing normal masticatory function were chosen. One dog aged about 12 months was for control, two dogs for experimental specimens were about 12 and 18 months old respectively. For chewing on the left side only, unilateral lower right premolar and molar were extracted in two experimental specimens. And then three dogs were sacrificed 10 months later. Frontal histologic sectioning of joints were done for the observation of the effects of one-side chewing. 24 specimens from three dogs were obtained and fixed in 10% formalin and routinly processed with H-E staining for histologic examination. The light microscopic findings were interpretated as follows: 1. Experimental specimen 1 aged about 22 months: In comparison with control and right non-chewing side, the proliferative and hypertrophic zone were increased at the mesial and lateral part of left chewing side condyle. There was no change of the articular tissue of temporal bone. 2. Experimental specimen 2 aged about 28 months: The articular tissues of adult joint were observed. The differences between the chewing and non-chewing side were not seen in the articular tissues of condyle and temporal bone.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.262-271
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• 2000

The purpose of this study was to estimate shear bond strength according to difference in Targis surface treatment and storage condition. 140 non-carious extracted human molars and Targis D210(Ivoclar, Liechtenstein) were used in the present study and were divided into 7 experimental groups respectively according to surface treatment of Targis. Group 1 ; No treatment, Group 2 ; $50{\mu}m$ aluminium oxide blasting, Group 3 ; 4% HF etching for 3 minutes, Group 4 ; 4% HF etching after blasting, Group 5 ; silane treatment after blasting, Group 6 ; silane treatment after 4% HF etching, Group 7 ; silane treatment after blasting and 4% HF etching. In Each group, one half of 20 specimens was stored in distilled water at $37^{\circ}C$ for 24 hours and the other half was stored at atmosphere for 24 hours respectively. Dentin surface was etched with 10% $H_3PO_4$ for 15 seconds and luting cement(Variolink II, Vivadent, Liechtenstein) was applied by manufacturer's recommendation. Shear bond strength for each group was then measured. To examine the failure patterns after shear bond test and to observe the change after surface treatment of Targis. Specimens were fabricated and observed under the SEM. Statistical analysis was performed by One Way ANOVA test and t-test. The results were as follows ; 1. The shear bond strength of the groups stored in water significantly lower than that of groups stored at atmosphere (P<0.05). 2. There was no significant difference in shear bond strength in groups stored in water (P>0.05). 3. The shear bond strength without surface treatment of Targis were lowest among all experimental groups in atmosphere condition(P<0.05). 4. There was no significant difference in bond strength between groups using the silane or not(P>0.05). 5. The groups treated by blasting, hydrofluoric acid and silane sequentially showed highest bond strength than that of other groups in atmosphere condition, but there was no significant difference(P>0.05). 6 The proportions of the specimens showing the mixed fracture failure were 20% in HF etching group and blasting + HF group, 40% in blasting + HF + silane group in atmosphere condition. All the specimens stored in water showed adhesive fracture failure.

• Journal of Environmental Health Sciences
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• v.47 no.2
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• pp.131-143
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• 2021

Objectives: This study aims to investigate the atmospheric concentration of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) and the urinary concentration of biomarkers in residents near the Shinpyeong·Jangrim Industrial Complex to compare them with those of residents in a control area. Methods: Hazardous air pollutants (PAHs and VOCs) were measured in an exposure area (two sites) and a control area (one site). Urine samples were collected from residents near the industrial complex (184 persons) and residents in the control area (181 persons). Multiple linear regression analysis was used to identify which factors affected the concentration of PAHs and VOCs metabolites. Results: The average atmospheric concentration of PAHs in Shinpyeong-dong and Jangrim-dong was 0.45 and 0.59 ppb for pyrene, 0.15 and 0.16 ppb for benzo[a]pyrene, and 0.29 and 0.35 ppb for dibenz[a,h]anthracene. The average atmospheric concentration of VOCs was 1.10 and 0.99 ppb for benzene, 8.22 and 11.30 ppb for toluene, and 1.91 and 3.05 ppb for ethylbenzene, respectively. The concentrations of PAHs and VOCs in residents near the Shinpyeong·Jangrim Industrial Complex were higher than those of residents in the control area. Geometric means of urinary 2-hydroxyfluorene, 1-hydroxypyrene, methylhippuric acid, and mandelic acid concentrations were 0.45, 0.22, 391.51, and 201.36 ㎍/g creatinine, respectively. Those levels were all significantly higher than those in the control area (p<0.05). In addition, as a result of multiple regression analysis, even after adjusting for potential confounding factors such as gender and smoking, the concentration of metabolites in urine was high in residents near the Shinpyeong·Jangrim Industrial Complex. Conclusion: The results of this study show the possibility of human exposure to VOCs in residents near the Shinpyeong·Jangrim Industrial Complex. Therefore, continuous monitoring of the local community is required for the management of environmental pollutant emissions.

• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.409-418
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• 2011

Objectives: The purpose of this study was to compare the microshear bond strength (${\mu}$SBS) and bonding interfaces of two-step total-etching and self-etching adhesive systems to three etch types of dentin either the acid etched, laser etched or laser and acid etched. Materials and Methods: The occlusal dentinal surfaces of thirty human molars were used. They were divided into six groups: group 1, 37% $H_3PO_4$ + Single Bond 2 (3M ESPE); group 2, Er:YAG laser (KEY Laser 3, KaVo) + Single Bond 2; group 3, Er:YAG laser + 37% $H_3PO_4$ + Single Bond 2; group 4, Clearfil SE Primer + Bond (Kuraray); group 5, Er:YAG laser + Clearfil SE Bond; group 6, Er:YAG laser + Clearfil SE Primer + Bond. The samples were subjected to ${\mu}$SBS testing 24 hr after bonding. Also scanning microscopic evaluations were made on the resin-dentin interfaces of six specimens. Results: The ${\mu}$SBS of group 2 was significantly lower than that of groups 1 and 3 in Single Bond 2 (p < 0.05). There were significant differences among the uSBS of groups 4, 5, and 6 in Clearfil SE Bond (p < 0.05). Very short and slender resin tags were observed in groups 2 and 5. Long and slender resin tags and lateral branches of tags were observed in groups 3 and 6. Conclusions: Treatment of dentin surface using phosphoric acid or self-etching primer improved the adhesion of Er:YAG lased dentin.

• 대한공업교육학회지
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• v.38 no.2
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• pp.267-286
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• 2013

Recently, the advanced company has been sparing no efforts in improving necessary core knowledge and technology to achieve outstanding work performance. In this rapidly changing knowledge-based society, the company has confronted the task of creating a high value-added knowledge. The role of R&D workforce that corresponds to the characteristic and role of knowledge worker is getting more significant. As the life cycle of technical knowledge and skill shortens, in every industry, the technical knowledge and skill have become essential elements for successful business. It is difficult to improve competitiveness of the company without enhancing the competency of individual and organization. As the competency development which is a part of human resource management in the company is being spread now, it is required to focus on the research of determining necessary competency and to analyze the competency of a core organization in the research institute. 'H' is the semiconductor manufacturing company which has a affiliated research institute with its own R&D engineers. Based on focus group interview and job analysis data, vision and necessary competency were confirmed. And to confirm whether the required competency by job is different or not, analysis was performed by dividing members into workers who are in charge of circuit design and design before process development and who are in the process actualization and process development. Also, this research included members' importance awareness of the determined competency. The interview and job analysis were integrated and analyzed after arranging by groups and contents and the analyzed results were resorted after comparative analysis with a competency dictionary of Spencer & Spencer and competency models which are developed from the advanced research. Derived main competencies are: challenge, responsibility, and prediction/responsiveness, planning a new business, achievement -oriented, training, cooperation, self-development, analytic thinking, scheduling, motivation, communication, commercialization of technology, information gathering, professionalism on the job, and professionalism outside of work. The highly required competency for both jobs was 'Professionalism'. 'Attitude', 'Performance Management', 'Teamwork' for workers in charge of circuit design and 'Challenge', 'Training', 'Professionalism on the job' and 'Communication' were recognized to be required competency for those who are in charge of process actualization and process development. With above results, this research has determined the necessary competency that the 'H' company's affiliated research institute needs and found the difference of required competency by job. Also, it has suggested more enthusiastic education methods or various kinds of education by confirming the importance awareness of competency and individual's level of awareness about the competency.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.20-28
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• 2013

The purpose of this study was to compare the ultra-violet(UV) radiation under the landscaping shade facilities and tree with natural solar UV of the outdoor space at summer middays. The UVA+B and UVB were recorded every minute from the $20^{th}$ of June to the $26^{th}$ of September 2012 at a height of 1.1m above in the four different shading conditions, with fours same measuring system consisting of two couple of analog UVA+B sensor(220~370nm, Genicom's GUVA-T21GH) and UVB sensor(220~320nm, Genicom's GUVA-T21GH) and data acquisition systems(Comfile Tech.'s Moacon). Four different shading conditions were under an wooden shelter($W4.2m{\times}L4.2m{\times}H2.5m$), a polyester membrane structure ($W4.9m{\times}L4.9m{\times}H2.6m$), a Salix koreensis($H11{\times}B30$), and a brick-paved plot without any shading material. Based on the 648 records of 17 sunny days, the time serial difference of natural solar UVA+B and UVB for midday periods were analysed and compared, and statistical analysis about the difference between the four shading conditions was done based on the 2,052 records of daytime period from 10 A.M. to 4 P.M.. The major findings were as follows; 1. The average UVA+B under the wooden shelter, the membrane and the tree were $39{\mu}W/cm^2$(3.4%), $74{\mu}W/cm^2$(6.4%), $87{\mu}W/cm^2$(7.6%) respectively, while the solar UVA+B was $1.148{\mu}W/cm^2$. Which means those facilities and tree screened at least 93% of solar UV+B. 2. The average UVB under the wooden shelter, the membrane and the tree were $12{\mu}W/cm^2$(5.8%), $26{\mu}W/cm^2$(13%), $17{\mu}W/cm^2$(8.2%) respectively, while the solar UVB was $207{\mu}W/cm^2$. The membrane showed the highest level and the wooden shelter lowest. 3. According to the results of time serial analysis, the difference between the three shaded conditions around noon was very small, but the differences of early morning and late afternoon were apparently big. Which seems caused by the matter of the formal and structural characteristics of the shading facilities and tree, not by the shading materials itself. In summary, the performance of the four landscaping shade facilities and tree were very good at screening the solar UV at outdoor of summer middays, but poor at screening the lateral UV during early morning and late afternoon. Therefore, it can be apparently said that the more delicate design of shading facilities and big tree or forest to block the additional lateral UV, the more effective in conditioning the outdoor space reducing the useless or even harmful radiation for human activities.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.3
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• pp.393-405
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• 2018

Volatile organic compounds (VOCs) are representative air pollutants due to their detrimental effects on human health and their role in formation of secondary organic aerosols. Assessments and monitoring programs of VOCs using periodic grab sampling like Tedlar bags, canisters, and sorbent traps provide limited information, often with delay times of days or weeks. Selected ion flow tube mass spectrometry (SIFT-MS) is an emerging analytical technique for the real-time quantification of VOCs in air. It relies on chemical ionization of the VOCs molecules in air introduced into helium carrier gas using $H_3O^+$, $NO^+$, and $O_2{^+}$ precursor ions. Real-time monitoring method of 60 VOCs in the ambient air was developed using TO-15 standard gas mixture. Calibration curves, method detection limit, and quantitation reproducibility of the target compounds were tested. Dynamic dilution system was used to dilute standard gas from 0.174 ppbv to 100 ppbv, where calibration curves showed good linearity with $r^2$> 0.95 in all target analytes. Limit of detection (LOD) all compounds were sub ppbv, and some halogenated compounds showed pptv levels. Seven consecutive analyses of target compounds showed good repeatability with relative standard deviation of less than 10%. One day monitoring of VOCs in ambient air was conducted in Geoje. Average concentration of target VOCs in Geoje were relatively lower than other regions, among which formaldehyde showed the highest concentration ($15.4{\pm}5.78ppbv$). SIFT-MS provided good temporal resolution data (1 data per 3.2 minute), which can be used for identifying ephemeral short-term event. It is expected that SIFT-MS will be a versatile monitoring platform for VOCs in ambient air.

• The Journal of Pediatrics of Korean Medicine
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• v.22 no.2
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• pp.81-114
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• 2008

Objectives : The purpose of this study is to investigate the effect of Jeseupwiryeongtang-gagam(JWTG) on atopic dermatitis by in vivo experiment using NC/Nga atopic dermatitis mouse, which has histological and clinical similarities to the atopic dermatitis of human. Methods : To investigate the effect of JWTG on AD, we evaluated atopic dermatitis-like skin lesions by clinical skin index and analyzed immunological parameters in peripheral blood mononuclear cells(PBMCs), splenocytes, draining lymph node(DLN) and performed skin histology in ears and dorsal skin of atopic dermatitis-like skin NC/Nga mouse in vivo. Results and Conclusions : In vivo, clinical skin severity score were significantly lower in JWTG group than control group. IgE, IL-6, $TNF-{\alpha}$, IgM, IgG2a and IgG2b levels in serum were decreased remarkably in JWTG group than control group and $IFN-{\gamma}$ production, secreted in Th1 cell were increased by JWTG. After experiment ended, we analyzed immunological cells ($CD3^+$, $CD19^+$, $CD4^+$, $CD8^+$, $CD3^+$$CD69^+$, $CD4^+$$CD25^+$ and $CD49b^+$) by flow cytometry. It resulted that total absolute number of $CD3^+$, $CD19^+$, $CD4^+$ and $CD8^+$ cells were recovered as normal and $CD3^+$$CD69^+$ were decreased significantly compared with control group in isolated DLN and PBMCs from NC/Nga mouse and total absolute number of $Gr-1^+$, $CD11b^+$ and $CD3^+$ in dorsal skin of NC/Nga mouse were decreased by JWTG. We analyzed ear, DLN, and neck-back skin after biopsy and dyeing by hematoxyline/eosin(H&E) and toluidine staining (mast cells marker) and obtained results that JWTG were effective to histological symptoms (dermal and epidermal thickening, hyperkeratosis and inflammatory cell infiltration). Ear thickness was decreased significantly than the control group and the size of inflammatory lymphocytes cells(ILC) and plasma cells(PC) in DLN were also decreased.

• Journal of environmental and Sanitary engineering
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• v.7 no.2
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• pp.111-128
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• 1992

According to the increase of population and industrialization, the quality of our drinking water are becoming worse by the contamination of resources, production of THM and other halogenated hydrocarbons during the purifying process, the problem of corroded water supplying pipeline, and the water reservoir tanks, Many people choose groundwater to drink instead of city tap water, but sometimes we get report about groundwater contamination by wastes, swage, septic tank, etc. It is reported that in U. S. over 20% of population are drinking groundwater, but U. S EPA reported the groundwater contamination by pesticides, herbicides, fungicides, fertilizer, and various chemical substances. Craun, et at announced the groundwater contamination by bacteria which are related with poor installation of septic tank. Johnson and Kross mentioned aboutmethemoglobinemia by NO3-N originated from human and animal feces, organic chemicals, and fertilizer, and as the results the infant mortality could be risen. Some scientist also reported the high concentration of metals in groundwaters and some cation and anions, and volatile organic compou nds. Authors investigated 80 groundwaters in urban, agricultural, and industrial area during last 3 month(June - August) to check any drinking water quality parameters are exceeding the standards. The results were as follow. 1, The average value of ammonia nitrate were within the standard, but 11.76% of urban area were exceeded the 10 rpm standard, in agricultural area 42.3175 were exceeded, and in industrial area 20.2% were exceeded the drinking water standard of 10 ppm. the highest concentration was 29.37 ppd in industrial area. 2. The mean value of metals is not exceeded the standard, but there were some groundwater whose Mn value was 0.424 ppm(standard is 0,3 ppm) in urban area, 0.737 rpm in agricultural area, and 5.188 ppm in industrial area. The highest Zn value was 1.221 ppm (standard is 1.0 ppm)was found in industrial area. 3. The percentage of contamination by general bacteria was 8.82% in urban area, 15.38% in agricultural area, and 15.00% in industrial area. Escherichia coil group was also contaminated by 35.29% in urban area, 30.76% in agricultural area, and 30.00% in industrial area. 4, The pH value was within the standard which means there was no influence by acid or alkali chemicals, nor acid rain Through the above results, all the groundwater should be tested to check the safety for drinking water and should make some alternative methods suitable for drink.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.307-313
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• 2015

Unpolished rice (UR) is considered to be a healthy alternative to white rice when coping with chronic diseases. In the present study, the fermented slurry of unpolished rice (FSUR) was evaluated with respect to its antimicrobial activities and biochemical characteristics, including the quantities of sugar, total soluble sugar, organic acids, free amino acids, pH, and physiological activity. The antimicrobial efficiency of FSUR was assessed using the paper disc-agar diffusion method. FSUR exhibited strong antimicrobial activity against six pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, and Yersinia enterocolitica) and two fermentation strains (Gluconacetobacter intermedius and Lodderomyces elongisporus). The antimicrobial activity of FSUR was higher than the commercial antibiotics, carbenicillin ($50{\mu}g/ml$) and tetracycline ($50{\mu}g/ml$) against S. aureus, E. coli, L. monocytogenes, P. aeruginosa, S. typhimurium, Y. enterocolitica, and L. elongisporus. Also FSUR had a high antioxidant activity. The microorganisms were isolated from FSUR using tryptic soy broth and yeast extract-peptone-dextrose agar media. The isolated microorganisms were characterized using physiological and biochemical analyses as well as by 16S rRNA gene sequencing and phylogenic analysis. 16S rRNA gene sequence analysis showed that the isolated microorganisms had a high similarity to G. intermedius, Lactobacillus casei, Lactobacillus plantarum, and Acetobacter peroxydans.