• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.79-87
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• 2014

PURPOSE. The aim of this study was to determine the efficiency of Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser in different output powers for removing permanent resin cement residues and therefore its influence on microshear bond strength compared to other cleaning methods. MATERIALS AND METHODS. 90 extracted human molars were sectioned in 1 mm thickness. Resin cement was applied to surface of sliced teeth. After the removal of initial cement, 6 test groups were prepared by various dentin surface treatment methods as follows: no treatment (Group 1), ethylene diamine tetra acetic acid application (Group 2), Endosolv R application (Group 3), 1.25 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 4), 2 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 5) and 3.5 W Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet laser irradiation (Group 6). The topography and morphology of the treated dentin surfaces were investigated by scanning electron microscopy (n=2 for each group). Following the repetitive cementation, microshear bond strength between dentin and cement (n=26 in per group) were measured with universal testing machine and the data were analyzed by Kruskal Wallis H Test with Bonferroni correction (P<.05). Fracture patterns were investigated by light microscope. RESULTS. Mean microshear bond strength ${\pm}$ SD (MPa) for each group was $34.9{\pm}17.7$, $32.1{\pm}15.8$, $37.8{\pm}19.3$, $31.3{\pm}12.7$, $44.4{\pm}13.6$, $40.2{\pm}13.2$ respectively. Group 5 showed significantly difference from Group 1, Group 2 and Group 4. Also, Group 6 was found statistically different from Group 4. CONCLUSION. 2 W and 3.5 W Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser application were found efficient in removing resin residues.

• Safety and Health at Work
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• 제2권3호
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• pp.290-300
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• 2011

Objectives: There is limited data regarding the toxicity of methylcyclohexane, despite its wide use in rubber adhesives, paint diluents, and cleansing agents. This study aimed to verify the toxicity and influence on the reproductive system of methylcyclohexane after its repeated injection in Sprague Dawley (SD) rats. Methods: Methylcyclohexane was injected subcutaneously into male and female SD rats once a day, five times a week, for 13 weeks at different doses (0, 10, 100, and 1,000 mg/kg/day) for each group. The toxicity of testing material was verified by observing the change in body and organ weight, hematological change, pathological findings, and effect on the reproductive system at each different concentration. Results: In the 1,000 mg/kg/day group, there were cases of animal deaths. In animals that survived, hematological changes, including a decrease in the red blood cell count, were observed. A considerable weight gain or loss and pathological abnormalities in the liver, kidney, and other organs were found. However, the 10 and 100 mg/kg/day groups did not cause deaths or other specific abnormalities. In terms of reproductive toxicity, there were changes in hormone levels, including a significant decrease in hormones such as estradiol and progesterone (p < 0.001) in male animals. Menstrual cycle change for female animals did not show concentration dependency. Conclusion: When injected repeatedly for 13 weeks, methylcyclohexane proved to be toxic for the liver, heart, and kidney at a high dose. The absolute toxic dose was 1,000 mg/kg/day, while the no observed adverse effect level was less than 100 mg/kg/day. The substance exerted little influence on the reproductive system.

• 한국환경복원기술학회지
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• 제5권2호
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• pp.25-33
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• 2002

This study was carried out to select the utilizable vegetations for the stabilization of slopes and river banks, landscape creation and water quality cleansing in dams, lakes and streams. In this study, 10 herbaceous plants were investigated for their survival and growth characteristics under complete and partly flooding conditions in the nursery. The ranking order of flooding tolerance based on survival ability showed that Iris pseudoacorus, Phragmites communis and Phragmites japonica were first, Typha angustata, Miscanthus sacchariflorus and Pennisetum alopecuroides were second, and Cymbopogon tortilis, Miscanthus sinensis, Kummerowia striata and Lolium multiflorum were last. That of flooding tolerance base on growth ability showed that Iris pseudoacorus, Phragmites communis, Phragmites japonica, Typha angustata and Miscanthus sacchariflorus were first, Pennisetum alopecuroides, Miscanthus sinensis and Kummerowia striata were second, and Cymbopogon tortilis and Lolium multiflorum were last. Espcially, Miscanthus sacchariflorus, Iris pseudoacorus, Phragmites japonica and Phragmites communis showed good survival and growth abilities when they were complete flooded for 60 days. Also high flooding tolerant species grow as better as flooding period longer under the partly flooding condition. It was found that Pennisetum alopecuroides and Kummerowia striata have excess moisture tolerance because they showed good survival and growth under the partly flooding condition. This study confirmed that the possibilities of utilizing Iris pseudoacorus, Typha angustata, Phragmites japonica, Phragmites japonica, Phragmites communis, Miscanthus sacchariflorus, Pennisetum alopecuroides and Kummerowia striata as the efficient plants for vegetation measures on the flooded slopes of dam and various impoundment sites.

• 기본간호학회지
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• 제6권3호
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• pp.359-368
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• 1999

Background : The purpose of this study was to determine whether cleansing the perineum and urethral meatus and using midstream urine affect the rate of bacterial contamination of urine specimens, and to determine the optimum urine collection method. We studied 41 asymptomatic healthy nursing school students. Women who were menstruating were not excluded from this study. Method : The first and midstream urine samples were collected during consecutive urinationsby each woman. The first sample was not a clean-catch specimen, and the second one was a clean-catch specimen. Both specimens were studied by urinalysis and bacterial culture with standard methods. Results : 41 women met the study criteria and 39 successfully completed the study. None of the urine cultures were positive. 68.3% of the non clean-catch first urine cultures, 53.7% of the non clean-catch midstream cultures, 33.3% of the first clean-catch urine culteres and 30.8% of the midstream clean-catch urine were found to be contaminated. There was a significant difference in the bacterial contamination rates between the first and midstream urine, and the clean-catch and non clean-catch urine(p=0.035, p =0.001 respectively). On urinalysis, 7.3% of the non clean-catch first urine, 7.3% of the non clean-catch midstream urine, 2.6% of the clean-catch first urine and 2.6% of clean-catch midstream urine were found to be above grade 2. Conclusions : According to our results, the bacterial contamination rate was the lowest in midstream and clean catch urine specimens. Threrfore it is recommended that the midstream clean-catch technique is the standard practice for collecting urine specimens for bacterial culture in women.

• Journal of Oral Medicine and Pain
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• 제40권2호
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• pp.41-46
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• 2015

Purpose: This study was performed to investigate a correlation among oral hygiene habits, dryness of mouth, and self-perceived oral malodor and therefore to find out self-care methods which could be a help to reduce oral malodor. Methods: A survey of 296 dental undergraduate students of School of Dentistry, Pusan National University, who wrote consents voluntarily and participated in this study, was conducted using a questionnaire consisting of 17 questions and analyzed to investigate a correlation among oral hygiene habits (frequency of tooth brushing, water gargling, and drinking water, etc.), dryness of mouth indicating the amount of salivary secretion, and self-perceived oral malodor. Results: There was no significant correlation between mechanical cleaning factors and self-perceived oral malodor. The factor showing a strong correlation with severe self-perceived oral malodor was dryness of mouth (p=0.000). Conclusions: There was no correlation between mechanical cleaning habits and self-perceived oral malodor. Participants who felt self-perceived oral malodor more tended to have rather good mechanical cleaning habits. The factor showing a strong correlation with severe self-perceived oral malodor was dryness of mouth. Therefore trying to increase salivary secretion is considered to be a help to reduce self-perceived halitosis.

• 대한치과보철학회지
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• 제36권2호
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• pp.273-292
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• 1998

The purpose of this study was to evaluate marginal fit of four all-ceramic crown systems 1) conventional In-Ceram, 2) copy-milled In-Ceram using Celay system, 3) IPS Empress, 4) OPC(Optimal Pressable Ceramic). All ceramic crowns were made on epoxy dies. The fabricated crowns were sandblasted, cleaned with ultrasonic cleansing, silanated, and cemented with Bistite composite resin cement. the selected marginal areas of the crowns were the labial, lingual, mesial, and distal surface. Each selected area of surface was $0.6{\times}1.6mm$ in dimension. The image of each marginal area was captured to computer files using DT-55 Frame Grabber and light microscope connected CCD camera. The marginal gaps were measured every $70{\mu}m$ using computer image analysis program. The results obtained were summarized as follows : 1. The marginal fit of four all-ceramic crowns were significantly different from each other(p<0.01), and mean marginal fit values obtained were $31.42{\pm}16.52{\mu}m$ in conventional In-Ceram, $55.45{\pm}27.90{\mu}m$ in copy-milled In-Ceram using Celay system, $44.36{\pm}24.59{\mu}m$ in IPS Empress, $47.21{\pm}20.42{\mu}m$ in OPC. 2. In the marginal fit of conventional In-Ceraw and copy-milled In-Ceram crowns using Celay system there was no significant difference between mesiodistal and buccolingual surface, but in the marginal fit of IPS Empress and OPC crowns, there was significant difference between mesiodistal and buccolingual surface(p<0.01). 3. The marginal fit of four kinds of all-ceramic crowns was clinically acceptable.

• 한국초등수학교육학회지
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• 제23권4호
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• pp.459-479
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• 2019

본 연구에서는 키워드 네트워크를 통해 국내 초등수학교육 분야의 대표적인 학술지인 『한국초등수학교육학회지』에 수록된 논문의 키워드를 대상으로 본 학술지의 연구 동향을 살펴보았다. 자료수집은 창간호부터 2018년까지 총 378편의 논문을 대상으로 하였으며, 논문에 포함된 총 1140개의 키워드들에 대하여 Krkwic 프로그램과 NodeXL 프로그램을 활용하여 빈도 분석 및 키워드 네트워크 분석을 실시하였다. 연구 결과 첫째, 빈도분석 결과 최소 5회 이상 출현하여 나타난 키워드는 48개로 수학과교육과정, 수학교과서, 학교수학, 수학문제해결, 수학영재 등이 있었다. 둘째, 키워드 네트워크 분석 결과에서 중요성이 높게 나타난 키워드는 수학교과서, 학교수학, 수학과교육과정, 수학문제해결, 수학적의사소통 등이 나타났다. 이러한 연구 결과를 바탕으로 본 학술지의 연구의 주요한 연구 주제어를 파악하고 연구 동향을 논의하였으며 연구의 제한점을 바탕으로 제언을 할 수 있었다.

• 한국치위생학회지
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• 제2권2호
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• pp.215-225
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• 2002

Objectives: Dental personnels have high chances of exposure to various infections during many dental procedures. This study was performed to investigate the state of infection control in the private dental clinics and prevention state of hepatitis B virus infection among the dental hygiene students in Kwanju city, Korea. Methods: Questionnaires were obtained from 94 dental hygiene students who participated in dental practice in private dental clinics for more than five weeks. Results: 83.9% of dentists and 17.2% of dental hygienists routinely used the mask for treating all patients, 32.3% of dentists and 6.5% of dental hygienists routinely used the rubber gloves. The use of protective eyeware was much lower in each group. Disinfectant was used in 52.7% for sanitization of dental instruments before cleansing. The prevalence of HBsAg and anti-HBs were 3.8% and 67.1% respectively, 52.7% of dental hygiene students had history of accidental needle stick. Conclusion: Routine use of personal barrier techniques by dental personnels should be emphasized. Dental hygiene students were not properly immunized against hepatitis B virus and had high incidence of accidental needle stick. It is necessary to establish specific regulations or recommendations for cross infection control in dental practice and to performed scheduled vaccination program for hepatitis B virus for dental hygiene students.

• 한방안이비인후피부과학회지
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• 제31권4호
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• pp.83-95
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• 2018

Objectives : This study was conducted to review about a prevention and management of acne Methods : We searched Korean research database by using keyword 'acne' and 'prevention' or 'management'. Korean research databases were Korean Studies Information Service System(KISS), Research Information Service System(RISS), Korean Medicine Information System(OASIS), National Digital Science Library(NDSL) and Jeonju Municipal Library. We classified studies identified by year, method, contents Results : Among 19 studies, 10 studies were articles and 9 studies were books. The proportion of studies published in 1990s was 26.3%, published in 2000s was 46.3%, published in 2010s was 26.3%. We analyzed 19 studies by classifying 4 categories that consist of Diet Management, Skin Management, Life Management, Exercise Management. In Diet Management, intake of fruits and vegetables was highly recommended, and intake of oily foods and high-fat foods was restricted. In Skin Management, thorough skin cleansing was highly recommended and skin contact was restricted. In Life Management, enough sleep and rest were highly recommended, and smoking was restricted. In Exercise Management, some of exercises to promote blood circulation were recommended. Conclusions : Various methods have been used for prevention and management of acne. It is necessary to systematically study the prevention and management of acne.

• 대한화장품학회지
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• 제29권2호
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• pp.251-270
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• 2003

소비자 욕구의 다양화와 관련 기술 등의 발달로 인하여 피부 미화, 청결 등의 단순한 효능만을 가지던 화장품이 이제는 주름개선, 미백 등의 실질적인 효능 효과를 가지는 제품으로 상품의 개발 방향이 변화되었다. 국내에서도 이러한 흐름에 발 맞추어 2000 년 식품의약품안전청 고시에 의해 화장품법이 제정되었고, 국내 화장품 산업이 발전할 수 있는 도약의 전기와 함께 본격적인 `기능성화장품'시대가 개막되었다. 2000 년 7 월 화장품 법 시행 이후 나름대로 정착되어가고 있는 기능성 화장품 제도가 변화하는 여성 소비자들에게 어떻게 이해되고 있는지를 라이프스타일 중심으로 파악해 봄으로써 라이프 스타일에 따른 기능성 화장품의 소비자 유형 분류에 대한 기초 정보 제공과 기능성 화장품 시장 세분화에 대한 마케팅 전략 수립의 기초 자료가 되리라 사료된다.