• Title/Summary/Keyword: cross-sectional area

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EFFECT OF A DESENSITIZER ON DENTINAL BOND STRENGTH IN CEMENTATION OF COMPOSITE RESIN INLAY (레진 인레이 합착시 지각과민처리제의 사용이 상아질 결합강도에 미치는 영향)

  • Han, Sae-Hee;Cho, Young-Gon
    • Restorative Dentistry and Endodontics
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    • v.34 no.3
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    • pp.223-231
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    • 2009
  • The purpose of this study was to evaluate the effect of a desensitizer on dentinal bond strength in cementation of composite resin inlay. Fifty four molar teeth were exposed the occlusal dentin. Class I inlay cavities were prepared and randomly divided into six groups. Control group: no agent, Group 1 : Isodan, Group 2 : One-step, Group 3 : All-Bond SE, Group 4 : Isodan + One-step, Group 5 : Isodan + All-Bond SE. Desensitizing agent and dentin bonding agents were applied immediately after the completion of the preparations. Impressions were then made. The composite resin inlays (Tescera, Bisco) were fabricated according to the manufacturers' guidelines. Cementation procedures followed a standard protocol by using resin cement (Bis-Cem, Bisco). Specimens were stored in distilled water at $37^{\circ}C$ for 24 hours. All specimens were sectioned to obtained sticks with $1.0{\times}1.0\;mm^2$ cross sectional area. The microtensile bond strength (${\mu}TBS$) was tested at crosshead speed of 1 mm/min. The data was analyzed using one way ANOVA and Tukey's test. Scanning electron microscopy analysis was made to examine the details of the bonding interface, 1. Group 1 showed significantly lower ${\mu}TBS$ than other groups (p<0.05). 2. There was no significant difference between the ${\mu}TBS$ of Group 3 and Group 5. 3. The ${\mu}TBS$ of Group 4 showed significantly lower than that of Group 2 (p<0.05). In conclusion, a desensitizer (Isodan) might have an adverse effect on the bond strength of composite resin inlay to dentin.

THE EFFECT OF DIFFERENT CURING MODES ON COMPOSITE RESIN/DENTIN BOND STRENGTH IN CLASS ICAVITIES (1급 와동에서 상아질과 복합레진의 결합강도에 대한 중합방법의 효과)

  • Baek, Shin-Young;Cho, Young-Gon;Song, Byeong-Choon
    • Restorative Dentistry and Endodontics
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    • v.33 no.5
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    • pp.428-434
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    • 2008
  • The purpose of this study was to compare the microtensile bond strength in Class I cavities associated with different light curing modes of same light energy density. Occlusal enamel was removed to expose a flat dentin surface and twenty box-shaped Class I cavities were prepared in dentin. Single Bond (3M Dental product) was applied and Z 250 was inserted using bulk technique. The composite was light-cured using one of four techniques, pulse delay (PD group), soft-start (SS group), pulse cure (PC group) and standard continuous cure (CC group). The light-curing unit capable of adjusting time and intensity (VIP, Bisco Dental product) was selected and the light energy density for all curing modes was fixed at $16J/cm^2$. After storage for 24 hours, specimens were sectioned into beams with a rectangular cross-sectional area of approximately $1mm^2$ Microtensile bond strength $({\mu}TBS)$ test was per- formed using a univel·sal testing machine (EZ Test, Shimadzu Co.). The results were analyzed using oneway ANOVA and Tukey's test at significance level 0.05. The ${\mu}TBS$ of PD group and SS group was higher than that of PC group and CC group. Within the limitations of this in vitro study, modification of curing modes such as pulse delay and soft start polymerization can improve resin/dentin bond strength in Class I cavities by controlling polymerization velocity of composite resin.

Integrated Schistosomiasis and Soil-Transmitted Helminthiasis Control over Five Years on Kome Island, Tanzania

  • Kaatano, Godfrey M.;Siza, Julius E.;Mwanga, Joseph R.;Min, Duk-Yong;Yong, Tai-Soon;Chai, Jong-Yil;Ko, Yunsuk;Chang, Su Young;Kullaya, Cyril M.;Rim, Han-Jong;Changalucha, John M.;Eom, Keeseon S.
    • Parasites, Hosts and Diseases
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    • v.53 no.5
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    • pp.535-543
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    • 2015
  • Integrated control strategies are important for sustainable control of schistosomiasis and soil-transmitted helminthiasis, despite their challenges for their effective implementation. With the support of Good Neighbors International in collaboration with National Institute of Medical Research, Mwanza, Tanzania, integrated control applying mass drug administration (MDA), health education using PHAST, and improved safe water supply has been implemented on Kome Island over 5 years for controlling schistosomiasis and soil-transmitted helminths (STHs). Baseline surveys for schistosomiasis and STHs was conducted before implementation of any integrated control strategies, followed by 4 cross-sectional follow-up surveys on randomly selected samples of schoolchildren and adults in 10 primary schools and 8 villages, respectively, on Kome islands. Those follow-up surveys were conducted for impact evaluation after introduction of control strategies interventions in the study area. Five rounds of MDA have been implemented from 2009 along with PHAST and improved water supply with pumped wells as other control strategies for complementing MDA. A remarkable steady decline of schistosomiasis and STHs was observed from 2009 to 2012 with significant trends in their prevalence decline, and thereafter infection rate has remained at a low sustainable control. By the third follow-up survey in 2012, Schistosoma mansoni infection prevalence was reduced by 90.5% and hookworm by 93.3% among schoolchildren while in adults the corresponding reduction was 83.2% and 56.9%, respectively. Integrated control strategies have successfully reduced S. mansoni and STH infection status to a lower level. This study further suggests that monitoring and evaluation is a crucial component of any large-scale STH and schistosomiasis intervention.

Histochemical and Physiological Characteristics during Korean Native Ogol Chicken Development (성장 단계에 따른 한국 재래 오골계 근육의 조직학 및 생리학적 특성)

  • Nam, Yun-Ju;Kim, Dong-Uk;Choi, Young-Min;Ryu, Youn-Chul;Lee, Sang-Hoon;Kim, Byoung-Chul
    • Food Science of Animal Resources
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    • v.27 no.4
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    • pp.401-408
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    • 2007
  • This study examined the histochemical and physiological characteristics during Korean native Ogol chickens (KNOC) development. The body weight, Pectoralis major and soleus muscle weights, and muscle samples were taken at hatching as well as at 3, 5, and 15 weeks of age. The fiber characteristics of the Pectoralis major and soleus muscles from the KNOC at hatching to 15 weeks of age were determined, and the deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein concentrations were measured from the left Pectoralis major muscles. A greater increase in body and muscle weights was detected between hatching and 3 weeks of age than during any other period. Moreover, the cross sectional area (CSA) of the fibers, as well as the total concentration of DNA, RNA, and protein also showed a greater increase betweenhatching and 3 weeks of age than during any other period. The KNOC breed is a dual purpose breed, however, the it has lower body and muscle weights than commercial meat type chickens or layer type chickens. Moreover, the KNOC breed has a small muscle fiber CSA of and a low nucleic acid concentration.

A Biomechanical Modeling of Human Pharyngeal Muscular Dysfunction by Using FEM(Finite Element Method) (유한요소법을 이용한 인두의 기능이상에 대한 생체역학적 모델)

  • Kim Sung Jae;Bae Ha Suk;Choi Byeong Cheol;Kim Sung Min
    • Journal of Biomedical Engineering Research
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    • v.24 no.6 s.81
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    • pp.515-522
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    • 2003
  • Pharynx is a system transporting foods by peristaltic motion(contraction and expansion movement! into the esophagus and functioning as airway passages. In this study, structural changes of pharyngeal dysfunction are analyzed by biomechanical model using CT and FEM(finite clement method). Loading condition was assumed that equal pressure was loaded sequentially to inside of pharyngeal tissue. In order to analyze the pharyngeal muscular dysfunction by biomechanical model. the pharyngeal dysfunctions was classified into 3 cases. Taking into account the clinical complication by neuromuscular symptoms such as pharyngeal dysfunction after stroke. we assumed that a change of material property is caused by muscular tissue stiffness. A deformation of cross sectional area of the pharynx is analyzed increasing the stiffness $25\%,\;50\%,\;75\%$ in each case on the basis of stress-strain relationship. Based on three-dimensional reconstruction of pharyngeal structure using limited factor - techniques and the optimization procedure by means of inverse dynamic approach. the biomechanical model of the human pharynx is implemented. The results may be used as clinical index illustrating the degree of pharyngeal muscular dysfunction. This study may be used as useful diagnostic model in discovering early deglutitory impediment caused by physiological or pathological pharyngeal dysfunction.

Evaluation of Diet Quality according to Nutrient Intake between Highly Educated, Married, Unemployed and Employed Women (고학력 기혼여성의 취업여부별 영양소 섭취로 본 식사의 질 평가)

  • Choi Ji-Hyun;Chung Young-Jin
    • Journal of Nutrition and Health
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    • v.39 no.2
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    • pp.160-170
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    • 2006
  • This study was conducted to provide foundation data for making health care policy for married women by assessing the dietary intake between highly educated married, employed and unemployed women. It is a direct interview, cross-sectional study with 24-hour recall method for one day. In selecting the subjects for this study, married, unemployed women were selected from a certain area (Daedeok Science Town) in Daejeon where there are high rates of highly educated women, and the married, employed women were selected from the teaching profession in order to avoid confounding due to including a variety of jobs. According to the Korean Standard Classification of Occupations, teaching is the representational occupation of highly educated, married women. Then, to prevent confounding due to age, we selected the subjects out of each age group at the same rate through random sampling. Women who had not graduated college, worked only part-time, or had no current spouse were excluded. As a result, 486 highly-educated, married, unemployed (250) and employed (236) women were used for analyzing data. The unemployed women consumed a higher amount of fat, cholesterol, sodium, vitamin C and folic acid while the employed women consumed a higher amount of iron, vitamin $B_l$ and vitamin $B_2$. P/M/S ratio being 1/1.18/1.05 and 1/1.05/0.87, for the unemployed women and the employed women, respectively, unemployed respondents had a higher saturated fat intake than those of employed. It is in excess of the standard ratio (1/1/1) of the Korean RDA. At the same time, in unemployed respondents the percent of energy intake from fat (24.8%, 23.2%) and animal fat (12.4%, 11.4%) were higher than those of employed respondents. The mean daily nutrient intake of calcium, zinc, and iron for both groups of respondents were lower than the Korean RDA. Both groups had phosphorus as the highest nutrient and calcium as the lowest nutrient of INQ (Index of Nutritional Quality) while nutrients with the INQ being less than 1 were calcium and iron. To sum up, the following conclusions can be made: Nutrition education and guidance for reduction of the intake of fat, especially animal fat, are necessary for unemployed women. In addition, highly educated, married, unemployed and employed women should increase the consumption of foods rich in iron and calcium to prevent anemia and osteoporosis, while decreasing the intake of phosphorus to balance proportions of calcium and phosphorus.

EFFECT OF INCREASING APPLICATION TIME OF SINGLE BOTTLE ADHESIVES TO MICROTENSILE BOND STRENGTH OF DRIED DENTIN (수종의 단일병 접착제의 적용 시간 연장이 건조 상아질의 미세인장 결합강도에 미치는 영향)

  • Kim, Hak-Geun;Kim, Dong-Jun;Hwang, Yun-Chan;Oh, Won-mann;Hwang, In-Nam
    • Restorative Dentistry and Endodontics
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    • v.30 no.6
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    • pp.435-441
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    • 2005
  • The purpose of this study was to evaluate the effect of increasing application time of single bottle adhesives (SBA) to microtensile bond strength (MTBS) of dried dentin. To expose the superficial dentin surfaces, human molars were sectioned perpendicular to the long axis of tooth. $32\%$ phosphoric acid gels were applied for 15s and rinsed. The teeth were randomly assigned to 3 groups ; S group (Single Bond), O group (One-Step), P group (Prime & Bond NT). Each group was divided to 3 subgroups (W: dentin wipe with wet gauge and light cured immediately, D, dentin dried for 30s and light cured immediately, 30: dentin dried for 30s and light cured after applying SBA for 30s). Composite resin was built up on the dentin surface and sectioned to obtain 20 specimens with $1mm^2$ cross sectional area and the MTBS was measured. For Single Bond, the mean MTBS of S-W and S-30 group were higher than that of S-D group statistically (P<0.05). For One-Step, the mean MTBS of O-D group was statistically lower than that of O-W group (P<0.05). For Prime & Bond NT, the mean MTBS of P-30 group was statistically lower than that of P-D group (P<0.05).

Low consumption of fruits and dairy foods is associated with metabolic syndrome in Korean adults from outpatient clinics in and near Seoul

  • Song, SuJin;Kim, Eun-Kyung;Hong, Soyoung;Shin, Sangah;Song, YoonJu;Baik, Hyun Wook;Joung, Hyojee;Paik, Hee Young
    • Nutrition Research and Practice
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    • v.9 no.5
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    • pp.554-562
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    • 2015
  • BACKGROUND/OBJECTIVES: The aim of this study was to examine differences in nutrient intake and food consumption by the presence of metabolic syndrome in Korean adults. SUBJECTS/METHODS: Study subjects in this cross-sectional study were recruited from four outpatient clinics in and near the Seoul metropolitan area of South Korea between 2006 and 2012. A total of 668 subjects (413 men and 255 women) aged ${\geq}30y$ were included in the final data analyses. For each subject, daily nutrient intake and food consumption were calculated using three days of dietary intake data obtained from a combination of 24-hour recalls and dietary records. To evaluate food consumption, mean number of servings consumed per day and percentages of recommended number of servings for six food groups were calculated. Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. The general linear model was performed to examine differences in nutrient intake and food consumption by sex and the presence of metabolic syndrome after adjustment for potential confounding variables. RESULTS: Nutrient intake did not differ by the presence of metabolic syndrome in both men and women. Men with metabolic syndrome had lower consumption and percentage of the recommendation for fruits compared with those without metabolic syndrome (1.6 vs. 1.1 servings/day, P-value = 0.001; 63.5 vs. 49.5%, P-value = 0.013). Women with metabolic syndrome showed lower consumption and percentage of the recommendation for dairy foods than those without metabolic syndrome (0.8 vs. 0.5 servings/day, P-value = 0.001; 78.6 vs. 48.9%, P-value = 0.001). CONCLUSIONS: Low intakes of fruits and dairy foods might be associated with the risk of having metabolic syndrome among Korean adults. Dietary advice on increasing consumption of these foods is needed to prevent and attenuate the risk of metabolic syndrome.

Trends in Child Sexual Abuse Literature -Articles Published from 2000 to 2008- (아동성학대 연구 경향 -2000~2008에 발표된 국내외 주요 학술지 논문을 중심으로-)

  • Yoon, Hye-Mee
    • Journal of the Korean Society of Child Welfare
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    • no.32
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    • pp.129-160
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    • 2010
  • This paper provides a review of research in the area of child(hood) sexual abuse. Particularly, the paper focuses on understanding the direction of research trends in Korea on this topic by evaluating the methodological changes, diversity of topics, and factors associated with research participants. The systemic, comprehensive review includes 28 articles in 14 primary Korean Journals and 261 articles in "Child Abuse and Neglect" and "Child Maltreatment" published from 2000 to 2008. Foci of the reviewing process were; (1) Do the transition of research methods follow scientific saturation? (2) What are the main subject areas of the field? (3)Who are the research participants and from where were they recruited? The review finds that overall, the number of CSA studies fluctuated in early 2000, but remained stable which means that academic interests have remained along with the social concern. The Korean CSA studies are imbalanced in terms of scientific saturation. Studies with theoretical methods are short in numbers, but there is a rapidly growing number of research using qualitative approaches. The review also highlights that most quantitative research utilized cross-sectional survey methodology. The major research themes that were most frequently found were studies on factors associated with CSA and evaluation of treatment modalities. However, research on perpetrators and measurement scale development were rather rare. In the CA&N and CM articles, study participants are frequently recruited from mental health clinics or related social agencies. Korean samples usually come from schools than communities and young children and their mothers seem to be excessively represented. Balanced research efforts are strongly suggested.

Investigation of Temperature Variation of Bridge Cables under Fire Hazard using Heat Transfer Analysis (열전달 해석을 통한 케이블교량 화재 시 케이블의 온도변화 분석)

  • Chung, Chulhun;Choi, Hyun Sung;Lee, Jungwhee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.5
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    • pp.313-322
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    • 2019
  • Recently, there have been frequent occurrences of bridge fires. Fires in cable-supported bridges can damage and brake cables due to high temperatures. In this study, fire scenarios that can occur on cable-supported bridges were set up. In addition, based on the results of vehicle fire tests, a fire intensity model was proposed and cable heat transfer analyses were performed on a target bridge. The analyses results demonstrated that temperature rises were identified on cables with a smaller cross-sectional area. Furthermore, vehicles other than tankers did not exceed the fire resistance criteria. When the tanker fire occurred on a bridge shoulder, the minimum diameter cable exceeded the fire resistance criteria; the height of the cable exceeding the fire resistance criteria was approximately 14 m from the surface. Therefore, the necessity of countermeasures and reinforcements of fire resistance was established. The results of this study confirmed that indirect evaluation of the temperature changes of bridge cables under fire is possible, and it was deemed necessary to further study the heat transfer analysis considering wind effects and the serviceability of the bridge when the cable temperature rises due to fire.