• Korean Journal of Health Education and Promotion
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• v.22 no.3
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• pp.49-63
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• 2005

Objectives: The study was designed to assess the trends of the incidence of HIV among young people and their sexual risk-taking behaviors by gender in Korean college students. Methods: The cross-sectional study was used from college students from selected 60 among 208 4-year colleges and universities in 9 provinces and Seoul. A self-reported anonymous questionnaire administered and completed to a national representative sample of 4-year college students from May 15th to June 14th in 2003. We analyzed 2,385 cases. The overall response rate was 82.0%. Results: After controlling age effects, male students were more likely to be sexually experienced than female students(40.0% vs. 8.1%), OR=5.5, p<.000. The proportions of 19 years and before reported for initiation of sexual intercourse were 18.6% for males and 3.2% for females. Males reported significantly younger ages than females at initiation of sexual intercourse(p<.01). Only 14.8% of current sexually active subjects reported consistent use of contraceptive methods. After controlling age effects, male students reported a higher proportion of sexually experienced respondents with one or more casual partners(excluding a formal partner) during the last 12 months than women(38.8% vs. 22.2%), OR=2.2, p<. 05. Conclusion : This study can conclude that although males students initiate sex earlier and have higher percentage of sexual experience, the percentage of sexually experience female students has risen rapidly compared to the past. This data revealed a number of young people were at risk for HIV infection. Both genders are equally likely to have engaged in inconsistent condom use even though when they have a sex with an unknown partner. These findings suggest that practical sex education focused on using condom use should have been included in the school curricular. Educational and community interventions need to prevent sex-related problems.

• Physical Therapy Korea
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• v.14 no.4
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• pp.44-49
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• 2007

The purpose of this study was to investigate the effects of auditory cues in the form of a metronome on gait initiation (GI) in Parkinson's disease (PD). 2 patients (mean age: 54 yrs) with idiopathic PD participated in the study. All patients (Hoehn and Yahr disability score of 2.0) were tested in the "on" state approximately 1.5 hours following the administration and fully responding to their PD medications. Subjects first initiated walking at self-initiated speeds to determine their cadences. Then, subjects were asked to initiate gait along the walkway while keeping pace with a metronome. The metronome rate (in beats/min) was set at a cadence 85% (slow condition), 100% (normal condition) and 115% (fast condition) of gait for each subject. Subjects were able to increase the speed of GI with faster cadence, but the speed of GI for the slow condition was similar to that of the normal condition. Swing toe-off was 578.3 ms for the fast condition, 709.4 ms for the normal condition and 736.2 ms for the slow condition. Respective times for swing heel-strike were 894.3 ms, 1110.2 ms and 1119.1 ms, and stance toe-off were 1105.4 ms, 1338.5 ms, and 1343.1 ms. Except for stance unloading ground reaction forces were greatest for the fast condition and smallest for the slow condition. It appears that PD patients were able to modulate GRFs and temporal events in response to auditory cues to achieve the peak acceleration force of the swing and stance limb. The findings from this study provided preliminary data, which could be used to investigate how PD patients modulate GRFs and temporal events during GI in response to tasks.

• Preventive Nutrition and Food Science
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• v.2 no.2
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• pp.96-100
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• 1997

Carcinogenicity of di(2-ethylhexyl)phthalate(DEHP) to the mose forestomach and its inhibitor activity for the initiation of Benzo[a]pyrene(BP)-induced mouse forestomach neoplasia were studied on the mouse forestomach carcinogenesis regimen. One hundred female ICR mice(6~7 weeks of age) were hosed in a poly-carbonate cage (4 mice/cage) in a humidity- and temperature-controlled room subjected to a semipurified diet for a week. Mice were divided into 4 treatment groups (25 mice/treatment): Basal diet, DEHP, BP, and BP+DEHP. On Monday and wednesday, 0.1ML DEHP mixed with 0.1ml olive oil (for DEHP and DEHP+BP treatment groups) or 0.1ml saline+0.1ml olive oil (for basal diet group) was intubated, p.o., and on Friday, 2mg BP dissolved in 0.2ml olive oil (for BP and BP+DEHP treatment groups) was intubated, p.o. This cycle was repeated for 4 weeks. Beginning with the first intubation of BP an continuing thereafter, body weight and food intake were recorded once and twice weekly, respectively. All surviving mice were sacrificed 22 weeks after the first dose of BP intubation and countered forestomach tumor. No tumor was formed by DEHP treatment. 5.75 tumors per mouse was formed by BP treatment, whereas its number was reduced to 4.53 by BP+DEHP treatment. Similar results were seen in the tumor incidence. Body weight gain was not affected by DEHP treatment, when compared to that b basal diet treatment. The body weight was significantly reduced by BP treatment, but its reduction was recovered to the level of the basal diet group by BP+DEHP treatment. No significant difference was seen in food intake among all treatment groups. These results indicate that DEHP lacks carcinogenic activity to the mose forestomach and rather inhibits the initiation of BP-induced mose forestomach neoplasia.

• Advances in pediatric surgery
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• v.15 no.2
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• pp.141-148
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• 2009

Peritoneal dialysis (PD) has been utilized for the children with end stage renal disease. Nevertheless, it is thought to promote inguinal hernia by increasing intraabdominal pressure. To investigate the clinical characteristics of inguinal hernia in children on PD, 155 cases of PD in children between January 1996 and June 2007 at Seoul National University Children's Hospital were reviewed retrospectively. Inguinal hernia developed in 16 cases (10.3 %, M:F=8:8). Hernia occurrence was not correlated to age. Eleven cases (69 %) of inguinal hernia developed in first 6 months after initiation of PD. All inguinal hernias were surgically repaired. No complications occurred related to inguinal hernia or surgery. Recurrent hernia developed in 1 patient (6.3 %) of 2 cases who had PD postoperatively on the day of surgery. In conclusion, inguinal hernia developed more frequently with children on PD than general population (3.5~5 %). The rate of hernia development was highest within the first 6 months following initiation of PD. After repair of hernia, we recommend to discontinue PD immediate postoperatively to prevent recurrence.

• Corrosion Science and Technology
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• v.7 no.5
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• pp.243-251
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• 2008

Magnesium alloys become popular research topic in last decade due to its light weight and relatively high strength-to-weight ratio in the energy aspiration age. Almost all structure materials are supposed to suspend stress. Magnesium is quite sensitive to corrosive environment, and also sensitive to environmental assisted cracking. However, so far we have the limited knowledge about the environmental sensitive cracking of magnesium alloys. The corrosion fatigue (CF) test was conducted. Many factors' effects, like grain size, texture, heat treatment, loading frequency, stress ratio, strain rate, chemical composition of environment, pH value, relative humidity were investigated. The results showed that all these factors had obvious influence on the crack initiation and propagation. Especially the dependence of CF life on pH value and frequency is quite different to the other traditional structural metallic materials. In order to interpret the results, the electrochemistry tests by polarization dynamic curve and electrochemical impedance spectroscopy were conducted with and without stress. The corrosion of magnesium alloys was also studied by in-situ observation in environmental scanning electron microscopy (ESEM). The corrosion rate changed with the wetting time during the initial corrosion process. The pre-charging of hydrogen caused crack initiated at $\beta$ phase, and with the increase of wetting time the crack propagated, implying that hydrogen produced by corrosion reaction participated in the process.

• Journal of Preventive Medicine and Public Health
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• v.52 no.4
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• pp.234-241
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• 2019

Objectives: To identify simultaneous behavioral changes in alcohol consumption, smoking, and weight using a fixed-effect model and to characterize their associations with disease status. Methods: This study included 7 000 529 individuals who participated in the national biennial health-screening program every 2 years from 2009 to 2016 and were aged 40 or more. We reconstructed the data into an individual-level panel dataset with 4 waves. We used a fixed-effect model for smoking, heavy alcohol drinking, and overweight. The independent variables were sex, age, lifestyle factors, insurance contribution, employment status, and disease status. Results: Becoming a high-risk drinker and losing weight were associated with initiation or resumption of smoking. Initiation or resumption of smoking and weight gain were associated with non-high-risk drinkers becoming high-risk drinkers. Smoking cessation and becoming a high-risk drinker were associated with normal-weight participants becoming overweight. Participants with newly acquired diabetes mellitus, ischemic heart disease, stroke, and cancer tended to stop smoking, discontinue high-risk drinking, and return to a normal weight. Conclusions: These results obtained using a large-scale population-based database documented interactions among lifestyle factors over time.

• Journal of Preventive Medicine and Public Health
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• v.10 no.1
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• pp.138-141
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• 1977

The total population of Korea in 1975 was 35,281,000 and population density was $357/km^2$, which is one of the highest rate of the countries in the world. In the early part of 1960's, prior to the initiation of national family planning program in 1962, the natural population increase rate in Korea was almost 3.0%. However, due to the positive support and activity of the national family planning program, the population growth rate has been dropped right below 2.0% in 1970, and decreased to 1.7% in 1975. The average number of children per woman was 5.8 in 1961 and has decreased steadily to 3.5 in 1975. However, traditional value like the 'boy-preference' concept may bring many difficulties of lowering the fertility rate, decreasing number of children less than three in the future. Rising marriage age which had much contributed to decrease the population growth showed preferably falling trends since 1970. There is a prospect that total number of birth will be continuously increased while the fertility rate may be fallen since the age group born during 'baby-boom' soon after the Korean war are becoming the reproductive age group at present time. Considering the above mentioned factors, family planning program should be much improved and strengthened and the government support is much required in order to meet the above mentioned objectives which maintain appropriate level of the population growth.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.340-343
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• 2007

The temperature variation of concrete pavement at early-age significantly affects the initiation and movement of joint cracks. For this analysis, we have built on IIA(Incheon International Airport) concrete pavement construction zone, and we measured the temperature and movement of the concrete slabs by using thermocouples, moisture sensors, V/W strain gages, and Demac discs. The analysis results showed that pavement's temperature significantly affected the joint movement. The widths of the joint cracks increased at evening and early in the morning when the temperature dropped but, those decreased in the day time when the temperature rose because of the effect of thermal expansion of the concrete slabs. The movements of the joints where the cracks never developed showed opposite trend to the cracked joints.

• Environmental Analysis Health and Toxicology
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• v.20 no.3 s.50
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• pp.209-213
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• 2005

Due to steady increase of childhood asthma, exposure to air toxics including PAHs have been thought as an etiology for the asthma. PAHs -involvement in airway inflammation, such as IgE production, is the potential mechanism of the PAHs-induced asthma. Cytochrome P450s (CYPs), particularly CYP1A1 is known enzyme to metabolite PAHs and to be induced by PAHs. The CYP1A1 expression has been emphasized as an biomarker for PAHs - exposure. The present study was performed to clarify the etiology of childhood asthma with PAHs-exposure using mRNA expression of CYP1A1 . The study Objects were Korean children who were asthma patients (cases) or other hospital controls (N=20; age,3 $\~$ 16; boys,56$\%$). As result, we detected expression of the CYP1A1 in all peripheral blood specimens which were collected from the subjects. Moreover, we found approx. 300 fold-higher expression of the CYP1A1 in the cases than that in the controls (p(<)0.01). When we considered age which was related to Asthma, the above significant trend was somewhat diluted, however, the relation between asthma and the Cypih i expression waL stronger than that between asthma and age (chi square,7.99 vs. 3.34). Therefore, our study supports that PAHs induce or worse childhood asthma and suggests application of expression of the CYP1A1 as an initiation or progress biomarker for PAHs - induced childhood asthma.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.2
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• pp.80-88
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• 2013

Purpose: To identify the predictive factors of long-term therapeutic response or resistance to lamivudine treatment in children and adolescents with chronic hepatitis B. Methods: Eighty one children and adolescents with chronic hepatitis B were included, who received lamivudine treatment for at least 6 months. Their condition was monitored for at least 12 months (12-88 months) thereafter. Twenty one (25.9%) were preschool children ($age{\leq}6$). For patients who had developed HBeAg seroconversion or breakthrough, univariate and multivariate analyses were used to identify the effects of age, gender, pretreatment alanine aminotransferase (ALT) and hepatitis B virus DNA levels. Results: HBeAg seroconversion occurred in 49 (60.5%) of the 81 patients after the initiation of the lamivudine therapy. In 65 patients whom were monitored for over 24 months, the seroconversion rate was significantly higher in younger patients (p=0.040), especially in those patients of preschool age ($age{\leq}6$, p=0.031). The seroconversion rate was significantly higher in higher pretreatment ALT (p=0.003). The breakthrough occurred in 21 (25.9%) of the 81. The breakthrough rate was lower in younger aged patients ($age{\leq}6$), and with higher pretreatment ALT levels, but no significant difference. Conclusion: Younger age is a good predictor of HBeAg seroconversion in children with long-term lamivudine treatment as well as high pretreatment ALT levels.