• The Journal of the Korean dental association
• /
• v.56 no.12
• /
• pp.695-706
• /
• 2018

Objectives: The purpose of this study was to investigate the ratio of 4 root canals and the incidence of Radix Entomolaris in mandibular first molars and find out anatomical difference according to number of roots by analysis of cone-beam CT images in a Korean population. Materials and Methods: Total 142 images containing mandibular first molars were selected from CBCT images taken from 2013 to 2017 at Gangneung-Wonju National University Dental Hospital. After reconstructing the image with reference to the Cemento-enamel junction, the root canals were detected at the bottom of the pulpal floor and the number of roots and root canals were analyzed. Various lengths and MLO-DLO-DBO angle were measured between each canal orifices and the external contour line of the tooth, and the distolingual canal wall thickness was measured. Student t-test was used for statistical significance. Results: Among the total 142 teeth, 4 canals were 42.2% and Radix Entomolaris was 25.3%. As the results of measuring various lengths and the angle, the distolingual canal orifice in Group 2(with Radix Entomolaris) tends to deviate to the lingual side than the mesiolingual canal orifice and to the mesial side than the distobuccal canal orifice. Besides, thickness of the distolingual canal wall in Group 2(with Radix Entomolaris) was significantly thinner than that of Group 1 at every level except pulpal floor level. Conclusion: It is necessary to consider the difference according to the presence of Radix Entomolaris in endodontic treatment.

• Journal of Food Hygiene and Safety
• /
• v.34 no.2
• /
• pp.199-204
• /
• 2019

This study aimed to generate a probability distribution model based on temperature data of frozen food storage facility as input variables for microbial risk assessment (MRA). We visited 8 food-handling businesses to collect temperature data from their cold storage warehouses. The overall mean temperature inside the storage facilities was $-20.48{\pm}3.08^{\circ}C$, with 20.4% of the facilities having above $-18^{\circ}C$, with minimum and maximum temperature values of -10.3 and $-25.80^{\circ}C$ respectively. Temperature distributions by space locations of natural and forced convection were $-22.57{\pm}0.84$ and $-17.81{\pm}1.47^{\circ}C$, $-22.49{\pm}1.05$ and $-17.94{\pm}1.44^{\circ}C$, and $-22.68{\pm}1.03$ and $-18.08{\pm}1.42^{\circ}C$ in the upper (2.4~4 m), middle (1.5~2.4 m), and lower (0.7~1.5 m) shelves, respectively. Probability distributions from the temperature data were obtained using the program @RISK. Statistical ranking was determined using goodness of fit to determine the probability distribution model. Our results show that a log-normal distribution [5.9731, 3.3483, shift (-26.4281)] is most appropriate for relative MRA conduction.

• Journal of Periodontal and Implant Science
• /
• v.49 no.1
• /
• pp.14-24
• /
• 2019

Purpose: To assess the influence of using different combinations of guided bone regeneration (GBR) materials on volume changes after wound closure at peri-implant dehiscence defects. Methods: In 5 pig mandibles, standardized bone defects were created and implants were centrally placed. The defects were augmented using different combinations of GBR materials: xenogeneic granulate and collagen membrane (group 1, n=10), xenogeneic granulate and alloplastic membrane (group 2, n=10), alloplastic granulates and alloplastic membrane (group 3, n=10). The horizontal thickness was assessed using cone-beam computed tomography before and after suturing. Measurements were performed at the implant shoulder (HT0) and at 1 mm (HT1) and 2mm (HT2) below. The data were statistically analysed using the Wilcoxon signed-rank test to evaluate within-group differences. Bonferroni correction was applied when calculating statistical significance between the groups. Results: The mean horizontal thickness before suturing was $2.55{\pm}0.53mm$ (group 1), $1.94{\pm}0.56mm$ (group 2), and $2.49{\pm}0.73mm$ (group 3). Post-suturing, the values were $1.47{\pm}0.31mm$ (group 1), $1.77{\pm}0.27mm$ (group 2), and $2.00{\pm}0.48mm$ (group 3). All groups demonstrated a loss of horizontal dimension. Intragroup changes exhibited significant differences in group 1 (P<0.001) and group 3 (P<0.01). Intergroup comparisons revealed statistically significant differences of the relative changes between groups 1 and 2 (P=0.033) and groups 1 and 3 (P=0.015). Conclusions: Volume change after wound closure was minimized by using an alloplastic membrane. The stability of the augmented horizontal thickness was most ensured by using this type of membrane irrespective of the bone substitute material used for membrane support.

• Kosin Medical Journal
• /
• v.33 no.3
• /
• pp.347-357
• /
• 2018

Objectives: Few studies of pediatric Epstein-Barr virus (EBV)-associated infectious mononucleosis (IM) have been conducted in Korea. We evaluated the clinical features of children with IM to define differences according to age. Methods: We conducted retrospective chart reviews of 68 children aged 0 to 15 years who were diagnosed by EBV-associated IM with EBV-Viral Capsid Antigen(VCA) IgM at laboratory test and were admitted between 2010 and 2014. The children were classified into four age groups: aged 0-3, 4-6, 7-9, and 10-15 years. Results: The age distribution of patients was as follows: 19 (27.9%) 0-3, 25 (36.8%) 4-6, 13 (19.1%) 7-9, and 11 (16.2%) 10-15. Fever was the most common presentation regardless of age. It was more common in the 0-3 group than the 4-6 group (P = 0.018). Pharyngitis was more common in the 7-9 group than the 0-3 group (P = 0.048), and myalgia was more common in the 10-15 group than the 0-3 group (P = 0.007). Pharyngitis was accompanied by lymphadenopathy, protracted fever, and rash. In the 0-3 age group, the prevalence of rash was higher while the percentage of atypical lymphocytes was lower, but there was no statistical support for this tendency. There were no differences in the frequency of hepatosplenomegaly or laboratory findings between age groups. Conclusions: IM is not uncommon in young children and its clinical presentation varies with age. Therefore, IM should be suspected in young febrile children with pharyngitis and rash despite low percentages of atypical lymphocytes.

• Journal of The Korean Society of Emergency Medicine
• /
• v.29 no.6
• /
• pp.649-655
• /
• 2018

Objective: This paper reports the possibility of using of a locking horizontal mattress suture technique in repairing lacerations that are difficult to suture with staples. Methods: Data were collected retrospectively over a 6-month period regarding the routine repair of scalp lacerations: those in areas injured by a high energy blunt mechanism, continued to bleed after pressure, nonlinear or damaged skin repaired with a locking horizontal mattress technique, and simple interrupted technique. The effects of the two techniques used to repair scalp lacerations on wound healing, complication rate, and patient satisfaction were examined. The categorical variables are expressed as the number and percent. A Mann-Whitney-Wilcoxon test was used for statistical analysis. A P-value less than 0.05 was considered significant. Results: Thirty-seven consecutive patients with scalp lacerations presented for care. Wound closure was accomplished with the locking horizontal mattress sutures in 40.5% (n=15) (median length, 5.0 cm; interquartile range [IQR], 4.0-7.0 cm). Simple interrupted sutures (median length, 4 cm; IQR, 3.0-5.0 cm) were used in 59.5% (n=22) (P=0.015). The frequency of additional bandage compression (P=0.008), frequency of exudative hemorrhage (P=0.018), and suture mark frequency at suture removal (P=0.047) were significantly lower in the locking horizontal mattress group. Conclusion: The locking horizontal mattress suture, which has the advantage of a horizontal mattress suture, may be one of the ways that can be used alternatively to treat scalp lacerations that difficult to suture with staples.

• The Korean Journal of Applied Statistics
• /
• v.34 no.5
• /
• pp.745-760
• /
• 2021

Prediction of a stock price has been a subject of interest for a long time in financial markets, and thus, many studies have been conducted in various directions. As the efficient market hypothesis introduced in the 1970s acquired supports, it came to be the majority opinion that it was impossible to predict stock prices. However, recent advances in predictive models have led to new attempts to predict the future prices. Here, we summarize past studies on the price prediction by evaluation measures, and predict the direction of stock prices of Samsung Electronics, LG Chem, and NAVER by applying various machine learning models. In addition to widely used technical indicator variables, accounting indicators such as Price Earning Ratio and Price Book-value Ratio and outputs of the hidden Markov Model are used as predictors. From the results of our analysis, we conclude that no models show significantly better accuracy and it is not possible to predict the direction of stock prices with models used. Considering that the models with extra predictors show relatively high test accuracy, we may expect the possibility of a meaningful improvement in prediction accuracy if proper variables that reflect the opinions and sentiments of investors would be utilized.

• Journal of the Korea Convergence Society
• /
• v.12 no.8
• /
• pp.197-205
• /
• 2021

In this study, we would like to confirm the impact of emotional intelligence perceived by members of medical institutions on job satisfaction and the mediating effect of self-efficacy. To test the hypothesis of the study, a survey was conducted on members of medical institutions (excluding doctors) in Gyeonggi Province, and statistical analysis was conducted using SPSS 22.0. First of all, the research results showed a positive impact only on use of emotion among the sub-factors of emotional intelligence in the impact relationship between emotional intelligence perceived by members on self-efficacy. Second, in the impact relationship of emotional intelligence on job satisfaction, which is a sub-factor of emotional intelligence, self-emotion appraisal, others' emotion appraisal, regulation of emotion, and use of emotion all showed positive effects. Third, the effect of members' self-efficacy on job satisfaction was also positive, and fourth, the mediating effect of self-efficacy between emotional intelligence and job satisfaction was also confirmed. Therefore, programs to improve members' emotional intelligence and self-efficacy are introduced and institutional needs are required.

• Journal of The Korean Society of Integrative Medicine
• /
• v.9 no.4
• /
• pp.283-289
• /
• 2021

Purpose : The purpose of this study is to investigate the effect of mid frequency electrical stimulation during squat exercise on the muscle activity and muscle activity ratio of vastus medialis oblique and vastus lateralis, and to prepare scientific basic data for exercise intervention using mid frequency electrical stimulation. Methods : This study was conducted with students from University C located in Busan, and among a total of 123 subjects, 12 subjects who complained of knee joint dysfunction between 80 and 90 points using the Kujala patellofemoral score (KPS) were used. All subjects participated in the experiment for 3 days, and MVIC values were measured for normalization of muscle activity values on the first day. For the two days, participants participated in the experiment and performed squat exercise or squat exercise receiving mid-frequency electrical stimulation in random order. Measurements were taken in the squat position immediately after the squat exercise, and muscle activities of vastus medialis oblique and vastus lateralis were measured. The measured data were compared through the dependent t test, and the statistical significance level was set to .05. Results : According to the results of this study, in the case of applying mid-frequency electrical stimulation together in the ratio of vastus medialis oblique and vastus lateralis muscle activity during squat exercise, higher values were observed compared to the case of not applying mid-frequency electrical stimulation together, and statistically significant. Also, when mid-frequency electrical stimulation was applied to both vastus medialis oblique and vastus lateralis activities during the squat exercise, higher values were shown compared to the case where the mid-frequency electrical stimulation was not applied together, but there was no statistically significant difference. Conclusion : The results of this study reported that mid-frequency electrical stimulation provided to vastus medialis oblique increased the muscle activity ratio of vastus medialis oblique and vastus lateralis. Therefore, the improvement of coordination due to the enhancement of the activity of vastus medialis oblique through mid-frequency electrical stimulation will be more helpful in the treatment of patellofemoral pain syndrome patient. In addition, it is hoped that the electrical stimulation method applied to exercise will be widely used.

• Journal of the Korea Convergence Society
• /
• v.12 no.4
• /
• pp.95-103
• /
• 2021

This study was aimed to investigate the education needs for prevention and control of infectious diseases by lifecycle based on age group and to provide the fundamental data to develop the educational programs. A research was conducted with 328 adults over 19 years old for a month of February 2021 through online and mobile survey by Gallup Korea. Research contents include the general characteristics, personal hygiene practices related to infection, perceived risks related to infection, importance and level of knowledge on infectious diseases, and education needs for prevention and control of infectious diseases. For the research data analysis, PASW Statistics Ver 20.0 was used as a statistical program. Ranks from analysis upon conversion as the formula of Borich needs to sum up with importance and knowledge level showed first (Borich 3.11) with treatments for infectious diseases; second (Borich 2.15) with process in case of suspicion and diagnosis of infectious diseases; third (Borich 1.75) with transmission routes of infectious diseases; fourth (Borich 1.73) with preventive ways of infectious diseases; fifth (Borich 1.50) with diagnostic and test methods of infectious diseases; sixth (Borich 1.45) with characteristics of infectious diseases; and seventh (Borich1.38) with main symptoms of infectious diseases. It is anticipated that development of educational programs applying education needs for prevention and control of infectious diseases in this research can contribute to enhance the physical health, mental health, and psychological well-being of the subjects.

• The Journal of the Korea Contents Association
• /
• v.21 no.10
• /
• pp.444-456
• /
• 2021

Economic abundance and the development of medical technology led to an aging society with an average life expectancy of 100 years, but retiring from the labor market at the age of 65 has become more difficult. This study aims to identify the influence of entrepreneurship, social support, and entrepreneurship mentoring as an effective support method to increase the entrepreneurial intention in order to enhance the entrepreneurial intention as an adult's second career development. In this study, data were collected using questionnaires from 340 adults, but only 319 were selected because 21 were judged to be inappropriate. For statistical analysis, SPSS 18.0 was used, and reliability test, factor analysis, and multiple regression analysis were used for hypothesis testing. The research results are as follows. First, as a result of examining the effects of adult entrepreneurship factors on entrepreneurship, it was found that among entrepreneurship, innovation and initiative had a significant positive (+) effect on entrepreneurship. Second, as a result of examining the effect of social support on entrepreneurial intention, it was found that family support had a significant negative (-) effect on entrepreneurial intention. Third, as a result of examining the effect of entrepreneurship mentoring on entrepreneurial intentions, it was found that role models and mentors had a positive (+) effect on entrepreneurial intentions. Fourth, as for the mediating effect of entrepreneurial efficacy, there were significant mediating effects of innovativeness → entrepreneurial efficacy → entrepreneurial intention, role model → entrepreneurial efficacy → entrepreneurial intention, mentor → entrepreneurial efficacy → entrepreneurial intention.