• Journal of the korean academy of Pediatric Dentistry
• /
• v.45 no.4
• /
• pp.418-425
• /
• 2018

This study was to measure and compare the amount of fluoride, microhardness and solubility of high viscosity glass ionomer and resin-reinforced glass ionomer during 84 days. Fuji IX GP EXTRA, Fuji IX GP, Fuji II LC and Filtek$^{TM}$ Z350XT stored in deionized water for 84 days to measure fluoride release, microhardness and solubility. As a result of measurement of fluoride release, all the glass ionomers showed the highest amount of fluoride release on day 1 and gradually decreased. Fuji IX GP EXTRA showed the highest amount of fluoride release and cumulative release. And Fuji IX GP and Fuji II LC showed no significant difference. Microhardness measurements showed that all experimental groups decreased 1 day after exposure to water. After 84 days, microhardness showed no significant difference between Fuji IX GP EXTRA and Fuji IX GP, and Fuji II LC was the lowest. In the solubility measurement, Fuji IX GP EXTRA, Fuji IX GP, and Fuji II LC increased rapidly to 21 days. After 21 days, there was no significant difference in the three groups. As a result, short term fluoride release affects solubility and microhardness, but long term fluoride release has no correlation. Through this study, the amount of fluoride, microhardness, and solubility of various glass ionomers were evaluated, and these properties could be applied clinically.

• Journal of Preventive Medicine and Public Health
• /
• v.39 no.2
• /
• pp.159-164
• /
• 2006

Objectives : This study was conducted to evaluate the effects of the personal stereo system on the hearing in adolescents. Methods : A total of 68 adolescents(age: 13-18 years) who visited the ENT Department at a University Hospital in Daegu were personally interviewed. The questionnaires were about general characteristics of the subjects, the time of personal stereo system use (year, hour) and place. Cumulative exposure to the personal stereo system was calculated by the product of the total years and the daily hours of their use. Pure tone audiometry was performed and the hearing threshold was measured at 500, 1000, 2000, 4000 and 8000 Hz. Results : The average time of using a personal stereo system a day was about 3 hours and 75% of the subjects used a personal stereo system for 2-5 years. The elevation of threshold was more prominent in the subjects who used personal stereo systems for 4 years and more compared with those subjects who used them for 3 years and under. The elevation of hearing threshold was also more prominent in the subjects who used personal stereo systems for 4 hours and more a day compared with those subjects who used personal stereo systems for 3 hours and under a day. The elevation of hearing threshold was more prominent in the subjects who used personal stereo systems for 13 hour. years and more compared to the subjects who used them 12 hour. years and under. Conclusions : These results suggest that the elevation of hearing threshold can happen to adolescents who used personal stereo systems for a long time. In order to prevent hearing loss, we need to teach adolescents appropriate usage of the personal stereo system and hearing tests should be included in the periodic school-based physical examination for the adolescents.

• Journal of Preventive Medicine and Public Health
• /
• v.31 no.1 s.60
• /
• pp.91-103
• /
• 1998

Under experimental conditions, UVB radiation, a type of ultra violet radiation, has shown to .elate with the occurrence of skin erythema (sun-burn) in human and skin cancer in experimental animal. Cumulative exposure to UVB is also believed to be at least partly responsible for the 'aging' process of the skin in human. It has also been observed to have an effect of altering DNA (deoxyribonucleic acid). UVB radiation is both an initiator and a promoter of non-melanoma skin cancer. Meta-analysis is a new discipline that critically reviews and statistically combines the results of previous researches. A recent review of meta-analysis in the field of public health emphasized its growing importance. Using a meta-analysis in this study, we explored more reliable dose-response relationships between UVB radiation and skin cancer incidence. We estimated skin cancer incidence using measured UVB radiation dose at a local area of Seoul (Shin chou-dong). The studies showing the dose-response relationships between UVB radiation and non-melanoma skin cancer incidence were searched and selected for a meta-analysis. The data for 7 reported epidemiological studies of three counties (USA, England, Australia) were pooled to estimated the risk. We estimated rate of incidence change of skin cancer using pooled data by meta-analysis method, and exponential and power models. Using either model, the regression coefficients for UVB did not differ significantly by gender and age. In each analysis of variance, non-melanoma skin cancer incidence after removing the gender and age and UVB effects was significant (p>0.01). The coefficients for UVB dose were estimated $2.07\times10^{-6}$ by the exponential model and 2.49 by the power model. At a local area of Seoul (Shinchon-Dong), BAF value were estimated 1.90 and 2.51 by the exponential and power model, respectively. The estimated BAP value were increased statistical power than that of primary studies that using a meta-analysis method.

• Tuberculosis and Respiratory Diseases
• /
• v.50 no.6
• /
• pp.693-703
• /
• 2001

Background : Smoking is the most important and consistent determinant of the development and progression of COPD(Ed Note : Define COPD). The fact that cigarette smokers develop a different type of COPD, chronic bronchitis and emphysema, with different clinical and pathological aspects, suggests that the development of COPD has a relationship with other smoking-associated factors beyond just a simple smoking history. The aim of this was to analyze the smoking habits and history of patients with COPD and to evaluate the development of different types of COPD according to patient's smoking habits. Method : To evaluate the differences in the smoking patterns of patients with chronic bronchitis and emphysema, a pulmonary function test was conducted, and the smoking history and patterns was obtained through a smoking history questionnaire by a direct personal interview from 333 male cigarette smokers diagnosed with COPD, in the Yeungnam university medical center(190 patients diagnosed with chronic bronchitis, 143 patients diagnosed with emphysema). Result : The patients with emphysema smoked earlier and had a higher smoking history(ie, more packyears, more total amounts of smoked cigarette, and more deep inhalation and longer duration of plain cigarette exposure) than those with chronic bronchitis. The depth of inhalation was also significantly higher in the emphysema patients after taking into account age, cumulative cigarette consumption and the type of cigarette smoked. Conclusion : Emphysema was more associated with the increasing degree of inhalation as assessed by the depth of inhalation. A high alveolar smoke exposure may be a significant risk factor for the development of emphysema.

• The Korean Journal of Pesticide Science
• /
• v.9 no.1
• /
• pp.70-80
• /
• 2005

To evaluate the exposure of molinate in agricultural environment and its effect against the non-target crop in air, this experiment was conducted to elucidate volatilization characteristics of molinate in aquatic condition and to determine critical concentration of molinate in the air causing phytotoxicity to Chili pepper. Cumulative volatilized rate of molinate from water was 22.7% at $35^{\circ}C$ for water temperature and 20 L/min for air velocity while 3.2% at $25^{\circ}C$ and 10 L/min within 47 hour after applied under closed system, respectively. The molinate concentrations in air above 60 cm height from soil surface of valley and open paddy rice field were reached the highest value of 18.17 and $11.59{\mu}g/m^3$, respectively within 24 hours after applying granular formulation at dose rate of molinate 150 g/1,000 $m^2$. However, their concentrations were drastically diminished to around 0.18 and $0.51{\mu}g/m^3$ level in 20 days after application, which volatilization pattern were similar to both regions. Also, the concentration of molinate in air above 60 cm height from soil surface was distributed higher 2 times than that above 180 cm height. Meanwhile, a phytotoxic symptom against the nearby chili pepper was revealed within three days after applied and molinate was detected $0.004{\sim}0.006$ mg/kg level from severe damaged leaves. The dose and exposure relations of molinate in the air against the non-target crop was also investigated in lab trial. The phytotoxic symptom, shriveled leaves, of the chili pepper was encountered by exposing two days with concentration of $13.6{\mu}g/m^3$, three days with $6.8{\mu}g/m^3$ or four days with $3.4{\mu}g/m^3$. The symptom was still recovered within four weeks after the plants had received fresh air. On the other hand, the phytotoxic response through root uptake of the herbicide in water culture was relatively insensitive, in which the symptom is observed ten days with the concentration of 300 ${\mu}g/L$.

• Journal of the Korean Society of Radiology
• /
• v.10 no.3
• /
• pp.181-186
• /
• 2016

Cardiac angiography(CA) or cardiac intervention(CI) is one of the major examination methods applied to the detection of cardiovascular diseases using X-rays. These CA and CI procedures require radiation exposure to patients and physicians. We evaluated the radiation dose to cardiac operator during the each case of CA and CI procedures. The number of patients is 113 patients in CA and 34 patients in CI. Mean fluoroscopy time, mean cine time, and mean total cumulative dose area product(DAP) in patients during CA and CI was 165.9 sec vs. 1200.0 sec, 30.31 sec vs 107.5 sec, and $37130.3mGy.cm^2$ vs $213312.6mGy.cm^2$, respectively. Mean dose of thyroid, over chest apron and under chest apron in operator during CA and CI was 15.84 uSv vs 89.81 uSv, 20.16 uSv vs 123.20 uSv, and 0.30 uSv vs 2.40 uSv, respectively. Mean effective dose of operator during CI was about 6 times greater than during CA. Also there was significant inter-relationship between fluoroscopy or cine time and effective dose in operator during CA and CI(p=0.001 and p=0.001, respectively).

• Pediatric Infection and Vaccine
• /
• v.31 no.1
• /
• pp.25-36
• /
• 2024

Purpose: Tetracycline is not recommended for children under 12 by guideline due to the risk of tooth discoloration. We aimed to assess the incidence of dental discoloration in Korean children prescribed tetracyclines and investigate whether its risk was greater in tetracycline-exposed children than in the general population. Methods: This population-based cohort study using the Health Insurance Review and Assessment service database included children aged 0-12 years exposed to tetracyclines for at least 1 day between January 2008 and December 2020. The primary outcome was the incidence rate of dental discoloration ≥6 months after prescription, and the standardized incidence ratio (SIR) was evaluated as secondary outcome. Results: 56,990 children were included-1,735 and 55,255 aged <8 and 8-12 years, respectively. 61% children were prescribed tetracycline for <14 days with mostly second-generation tetracyclines, doxycycline (61%) and minocycline (35%). The 5- and 10-year cumulative incidence rates of dental discoloration were 4.1% (95% confidence interval [CI], 3.0-5.7%) and 5.7% (95% CI, 4.1% to 7.8%), respectively, in the 0-7 years age group and 0.8% (95% CI, 0.7% to 0.9%) and 1.3 (95% CI, 1.1% to 1.4%), respectively, in the 8-12 years age group. Tetracycline exposure did not increase such risk compared to that in the general population (SIR, 1.08; 95% CI, 0.69 to 1.60). Conclusions: The incidence of dental discoloration was lower than previously suggested. Relieving the age restriction for prescribing tetracyclines may be considered.

• Journal of Life Science
• /
• v.28 no.7
• /
• pp.819-826
• /
• 2018

Orostachys japonicus (OJ) is a medicinal herb with immunoregulatory, anti-aging, anti-oxidative, and many other therapeutic properties. The purpose of this study was to elucidate the anti-cancer property of cultivated OJ. SW480 cell viability was significantly reduced by cumulative exposure to OJ extract. We also observed inhibitory effects of OJ after 72 hr through the growth and migration of SW480 cells using scratch assay. SW480 cells in OJ-free medium began to move into the scratch site at 24 hr; however, cells in medium containing OJ did not migrate into the scratch site until 48 hr. Male C57BL/6 mice (4 weeks old) were orally administered OJ extract for 31 days before injection of SW480 cells. At 7, 14, and 28 days after subcutaneous injection of SW480 cells, tumor weight and volume were analyzed. The body weight of the OJ-treated group was continuously increased during administration of the OJ extract relative to the control group. Injection of SW480 cells caused a reduction in body weight in all groups; however, the OJ-treated group exhibited a significant increase in body weight after 14 days. Tumor weight and volume were lower in the OJ-treated group than in the control group after 28 days. Although these results suggest that OJ suppresses the proliferation and migration of human colon cancer cells, additional studies are required to provide preclinical evidence before launching clinical trials evaluating OJ as an anti-cancer biohealth product.

• Journal of Chest Surgery
• /
• v.39 no.5 s.262
• /
• pp.347-353
• /
• 2006

Background: Despite recent advances in surgical technique and perioperative care of total anomalous pulmonary venous return (TAPVR), post-repair pulmonary vein stenosis (PVS) remains as a serious complication. We thought that the most important factors of TAPVR repair to prevent PVS were good exposure, proper alignment, and sufficient stoma size. We analyzed our experience retrospectively. Material and Method: Between Jan. 1995 and Feb. 2005, we studied 74 patients diagnosed with TAPVR suitable for biventricular repair. Supra-cardiac type (n=41, 55.4%) was the most common. Mean CPB time, ACC time, and TCA (40.5%, 30/74) time were $92.1{\pm}25.9\;min,\;39.1{\pm}10.6\;min$, and $30.2{\pm}10.7\;min$, respectively. Mean follow-up duration was $41.4{\pm}29.1$ months and follow-up was possible in all patients. Result: The median age and body weight at operation were 28.5 days ($0{\sim}478$ days) and 3.4 kg $(1.4{\sim}9\;kg)$. Early mortality was 4.1% (3/74). Causes of death were pulmonary hypertensive crisis, sepsis, and sudden death. There was PR-PVS in 2 patients (early: 1, late: 1). Both patients were cardiac type TAPVR drained to coronary sinus. Re-operations were done but only one patient survived. Cumulative survival rate in 5 year and percent freedom from PVS were $94.5{\pm}2.7%\;and\;97.2{\pm}2.0%$, respectively. Conclusion: There was no PVS in patients who underwent extra-cardiac anatomosis between LA and CPVC. Therefore it could be said that our principle might be effective in preventing PR-PVS in patients suitable two-ventricle.

• Journal of radiological science and technology
• /
• v.39 no.2
• /
• pp.237-246
• /
• 2016

This study is therefore aimed at measuring the surface dose rate and the spatial dose rate in and outside the radionuclide facility in order to ensure safety of the patients, radiation workers and family care-givers in their use of such equipment and to provide a basic framework for further research on radiation protection. The study was conducted at 4 restrooms in and outside the radionuclide facility of a general hospital in Incheon between May 1 and July 31, 2014. During the study period, the spatial contamination dose rate and the surface contamination dose rate before and after radiation use were measured at the 4 places-thyroid therapy room, PET center, gamma camera room, and outpatient department. According to the restroom use survey by hospitals, restrooms in the radionuclide facility were used not only by patients but also by family care-givers and some of radiation workers. The highest cumulative spatial radiation dose rate was 8.86 mSv/hr at camera room restroom, followed by 7.31 mSv/hr at radioactive iodine therapy room restroom, 2.29 mSv/hr at PET center restroom, and 0.26 mSv/hr at outpatient department restroom, respectively. The surface radiation dose rate measured before and after radiation use was the highest at toilets, which are in direct contact with patient's excretion, followed by the center and the entrance of restrooms. Unsealed radioactive sources used in nuclear medicine are relatively safe due to short half lives and low energy. A patient who received those radioactive sources, however, may become a mobile radioactive source and contaminate areas the patient contacts-camera room, sedation room, and restroom-through secretion and excretion. Therefore, patients administered radionuclides should be advised to drink sufficient amounts of water to efficiently minimize radiation exposure to others by reducing the biological half-life, and members of the public-family care-givers, pregnant women, and children-be as far away from the patients until the dose remains below the permitted dose limit.