• International Journal of Highway Engineering
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• v.5 no.3 s.17
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• pp.1-9
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• 2003

This study was performed to evaluate the effect of various joint sealant on reducing the reflection cracking of asphalt concrete overlay on cement concrete pavement. The test method used was an accelerated reflection cracking test in shear mode, which was developed for evaluation of reflection cracking resistance of overlaid asphalt concrete in laboratory. The test results showed that use of joint sealants resulted in a significant reduction of reflection cracking. When sealant E was used, the fatigue life was the highest, with relatively larger horizontal deformation. When Sealant B was used, the dynamic stability was the highest with the smallest horizontal deformation. In general, the greater the tensile strength of sealant, the better the crack resistance of the mixture.

• Toxicological Research
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• v.33 no.2
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• pp.165-171
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• 2017

Bisphenol A (BPA) is a monomer used in a polymerization reaction in the production of polycarbonate plastics. It has been used in many consumer products, including plastics, polyvinyl chloride, food packaging, dental sealants, and thermal receipts. However, there is little information available on the inhalation toxicity of BPA. Therefore, the aim of this study was to determine its inhalation toxicity and effects on the estrous cycle, spatial learning, and memory. Sprague-Dawley rats were exposed to 0, 10, 30, and $90mg/m^3$ BPA, 6 hr/day, 5 days/week for 8 weeks via whole-body inhalation. Mortality, clinical signs, body weight, hematology, serum chemistry, estrous cycle parameters, performance in the Morris water maze test, and organ weights, as well as gross and histopathological findings, were compared between the control and BPA exposure groups. Statistically significant changes were observed in serum chemistry and organ weights upon exposure to BPA. However, there was no BPA-related toxic effect on the body weight, food consumption, hematology, serum chemistry, organ weights, estrous cycle, performance in the Morris water maze test, or gross or histopathological lesions in any male or female rats in the BPA exposure groups. In conclusion, the results of this study suggested that the no observable adverse effect level (NOAEL) for BPA in rats is above $90mg/m^3$/6 hr/day, 5 days/week upon 8-week exposure. Furthermore, BPA did not affect the estrous cycle, spatial learning, or memory in rats.

• Korean Journal of Head & Neck Oncology
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• v.28 no.1
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• pp.8-11
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• 2012

배경 및 목적 : 섬유소 응고제(fibrin sealants)는 다양한 두경부수술에서 지혈목적으로 사용되고 있다. 본 연구의 목적은 배액관을 삽입하지 않는 갑상선 수술에서 섬유소 응고제의 효용성과 안정성을 알아보고자 하였다. 재료 및 방법 : 최근 1년간 108명의 갑상선 수술환자 중에서 수술 후 배액관의 삽입없이 수술을 받은 103명의 환자를 대상으로 하여 임상적인 특징을 분석하였다. 결과 : 103명의 대상환자 중에서 남성은 16예, 여성은 87예였다. 대상환자의 평균연령은 $46.7{\pm}13.0$세였고, 연령분포는 17세에서 72세였다. 갑상선 종물의 평균크기는 $2.08{\pm}1.61cm$였고, 종물의 크기는 최소 0.2cm에서 최대 10.0cm까지의 분포를 보였다. 수술에는 갑상선 엽절제술이 5예, 갑상선반절제술이 41예, 아갑상선 절제술이 8예, 갑상선 전절제술이 6예, 갑상선 전절제술과 중심경부림프절 절제술이 37예, 갑상선 전절제술과 선택적경부림프절 절제술이 6예가 있었다. 수술 후 합병증은 11예(10.6%)에서 발생하였고, 발생한 합병증으로는 장액성종창이 3예, 혈종이 1예, 일측성 성대마비가 3예, 저칼슘혈증이 4예 있었다. 성대마비는 수술 후 3개월 이내에 모두 호전되었고, 장액성 종창은 반복적인 세침흡인으로 호전되었다. 1예의 혈종은 지연성으로 발생하였고, 수술 후 5일째에 수술을 통해 제거하였다. 결론 : 이러한 결과에 근거하여 갑상선 수술에서 섬유소 응고제의 사용은 다양한 갑상선 수술에서 효과적인 지혈과 함께 안전하게 사용될 수 있으며, 배액관의 삽입을 감소시켜 줄 수 있을 것으로 생각된다.

• Journal of Korean society of Dental Hygiene
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• v.13 no.3
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• pp.501-507
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• 2013

Objectives : The purpose of this study was to evaluate the effect of the family dentist system on oral health status of children and adolescents of Community Children's Centers in Busan, Korea. Methods : The subjects of this study were 81 children and adolescents, 6 to 14 years old, using Community Children's Centers. The oral health survey was conducted on the subjects from the starting stage of family dentist program in 2009 to the evaluation stage in 2010. Dental health status was examined by a trained dentist according to the guideline proposed by the World Health Organization. In addition, the information on the oral health knowledge, belief, and process of dental care were obtained using questionnaires. Data were analyzed using the paired samples t-test. Results : Percentages of subjects with fissure sealants on permanent teeth and filling rate among DMF teeth of 2010 year were higher than those of 2009 year (P<0.05). However, the rate of decayed teeth among DMF teeth of 2010 year was lower than those of 2009 year (p=0.049). Conclusions : These findings showed that the family dentist system brought a positive effect on caries prevention and proper dental care of children and adolescents of the Community Children's Centers.

• Journal of Korean society of Dental Hygiene
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• v.20 no.4
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• pp.535-543
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• 2020

Objectives: The aim of this study was to investigated the surface roughness and change in the amount of adhesion of Streptococcus mutans to the commercial pit and fissure sealant containing cerium oxide nano particles(CNPs). Methods: The CNPs was incorporated into a commercial pit and fissure sealant at 0-4.0 wt%. Disk Specimens (ϕ 10 mm × 2 mm) were prepared by light polymerization the front and back for 40s. Average surface roughness was measured and Streptococcus mutans adhesion was observed under confocal laser scanning microscopy (CLSM) after 24 hour. Data were statistically analyzed by one-way ANOVA and Tukey HSD^a post-hoc test. Results: Difference of the surface roughness(Ra) between groups was not statistically significant in both non CNPs group and CNPs group(p>0.05). In CNPs group, the amount of S. mutans adhesion was significantly different between control group and decreased in order of CNPs 4.0, CNPs 0.5, CNPs 1.0 and CNPs 2.0(p<0.05). Conclusions: Within the limitation of this study, these aspects of oral bacteria performances suggest potential usefulness of the CNPs incorporation, especially CNPs 1% and 2%, in pit and fissure sealant for inducing antibacterial effect.

• Analytical Science and Technology
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• v.18 no.3
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• pp.206-215
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• 2005

Polychlorinated biphenyls (PCBs) were commercially produced as complex mixtures beginning in 1929. The PCBs manufactured commercially are known by a variety of trade names including; Aroclor (USA), Phenoclor (France), Kaneclor (Japan), Sovol (USSR) and so on. PCBs are a class of 209 congeners that were widely used in a wide variety of applications, including dielectric fluid in transformers and large capacitors; heat transfer fluids; hydraulic fluids; lubricating and cutting oils; and as additives in pesticides, paints, adhesives, sealants, and plastics. The quantification methods of peak matching and coefficient comparison were compared using the Aroclor 1242, 1248, 1254, 1260 standards. Also, six transformer oils were analyzed as a main source of polychlorinated biphenyls (PCBs) emission into the environment. The transformer oils contained the pure and mixed of Aroclor 1242, Aroclor 1254, and Aroclor 1260. The analytical results using two quantification methods showed the little difference between the measured results.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.6-10
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• 2012

The main objective of this work was studying the influence of paraffin oil(PO) on the adhesion properties at low temperature in styrene-butadiene-styrene(SBS) copolymer and crumb rubber(CR) modified asphalt. The temperature susceptibility of SBS/CR asphalt and PO/SBS/CR/asphalt blends were measured by penetration and softening point. Adhesion properties at low temperature and dispersion of modifiers in PO/SBS/CR/asphalt blends were evaluated by universal test machine and florescence microscopy, respectively. The adhesion properties of PO/SBS/CR/asphalt blends at low temperature increased in the proportion of SBS contents with both 5 and 10 wt % of paraffin oil. Results showed that the maximum tensile adhesion strength and toughness energy at $-20^{\circ}C$ were obtained when PO and SBS contents were 10 wt % and 6 wt %, respectively. The addition of PO is effective for enhancing the flexibility of SBS/CR/asphalt blends and leads to the increase of toughness at low temperature.

• Molecules and Cells
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• v.26 no.1
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• pp.74-80
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• 2008

Bisphenol A bis (2,3-dihydroxypropyl) ether ($BADGE.2H_2O$) is a component of commercial liquid epoxy resins commonly used in the food-packing industry and in dental sealants. There is evidence that it has significant estrogenic activity. Nur77 plays a crucial role in the regulation of certain genes involved in LH-mediated steroidogenesis in testicular Leydig cells. It was previously demonstrated that Bisphenol A (BPA) stimulates Nur77 gene induction and steroidogenesis. In this study, we investigated the effects of $BADGE.2H_2O$ on Nur77 gene expression and steroidogenesis. Northern blot analysis showed that it increased the expression of Nur77 mRNA and protein, and transient transfection assays demonstrated that it increased the promoter activity and transactivation of Nur77. It also increased the expression of certain steroidogenic genes, such as StAR and $3{\beta}$-HSD. Finally, over-expression of a dominant negative Nur77 cDNA via adenoviral infection reduced $BADGE.2H_2O$-mediated progesterone biosynthesis. These results indicate that $BADGE.2H_2O$ disrupts testicular steroidogenesis by increasing Nur77 gene expression.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.489-501
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• 1996

This study was to evaluate shear bond strength of fluoride-releasing sealant and nonfluoride releasing sealant to enamel surface of bovine tooth. 80 extracted bovine teeth were randomly assigned to four groups, and four kinds of sealants including Teethmate-A(Kuraray Co.), Teethmate-F(Kuraray Co.), Helioseal(Vivadent Co.), Helioseal-F(Vivadent Co.) were bonded to exposed enamel surfaces using silicon plate. Shear bond strength was determined in an instron universal testing machine at a crosshead speed of 1mm/min. Then, the fracture surfaces of test specimens were investigated with scanning electron microscope. The obtained results were as follows; 1. The shear bond strength decreased in the following order : Teethmate-A(18.31MPa), Teethmate-F(11.90MPa), Helioseal (11.74 MPa), Helioseal-F(10.64MPa). 2. The shear bond strength of Teethmate-A showed significantly higher than that of Teethmate-F(P<0.05), but Helioseal and Helioseal-F didn't showed statistically different(P<0.05). 3. According to the SEM, Teethmate-A group showed cohesive failure, and Teethmate-A group & Helioseal group showed mixed pattern of cohesive and adhesive failure and Helioseal-F group showed adhesive failure.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.89-94
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• 2019

Glass base sealant is required as a ceramic-ceramic joining material between α-alumina insulation cap and β-alumina electrolyte tube in the development of NaS battery cell package for electrical energy storage system. The fabrication of glass frit by thermal quenching method, phase analysis, particle size analysis, coefficient of thermal expansion and surface roughness according to the glass compositions were analyzed for the fabrication of glass sealing paste for ceramic-ceramic joining. Also, a new evaluation method of the adhesion strength of glass sealant at the small area in ceramic-ceramic joining component was proposed using conventional Dage bond tester that was used to measure the adhesion of solder ball joint.