• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.1
• /
• pp.1-7
• /
• 2011

Purpose: The purpose of this study was to investigate the cutting efficiency of coarse grit diamond burs with air-turbine handpiece on natural tooth. Materials and methods: Four groups of coarse grit diamond bur were selected: Komet (A), Shofu (B), Premier (C), and Mani (D). The extracted maxillary central incisors were used, and ten cuts were made on each specimen, using the rotary diamond burs. The surface of each bur was measured at the upper, middle, and bottom of the bur with confocal laser scanning microscope and imaged with SEM. The data were analyzed with one-way ANOVA and t-test at the significance level of 0.05. Results: The surface roughness was measured. At the A diamond bur, the Sa values were $52.93\;{\mu}m$, $48.32\;{\mu}m$, $46.79\;{\mu}m$, $45.06\;{\mu}m$, and $43.43\;{\mu}m$ for control, test 1, 2, 3, and 4 respectively. The Sa values were $50.68\;{\mu}m$, $45.62\;{\mu}m$, $44.41\;{\mu}m$, $44.10\;{\mu}m$, and $42.46\;{\mu}m$ for B diamond bur, $58.02\;{\mu}m$, $55.53\;{\mu}m$, $52.22\;{\mu}m$, $48.26\;{\mu}m$, and $45.36\;{\mu}m$ for C diamond bur, and $50.11\;{\mu}m$, $46.73\;{\mu}m$, $45.46\;{\mu}m$, $42.58\;{\mu}m$, and $41.80\;{\mu}m$ for D diamond bur. Surface roughness after each bur use showed significant changes, but no significant difference was found in surface roughness change between bur systems. Conclusions: Surface roughness in the same bur system showed significant differences after each tooth preparation. However no statistically significant differences were found in surface roughness between bur systems. The SEM images between control and test 4 showed the abraded particles.

• Advances in pediatric surgery
• /
• v.7 no.2
• /
• pp.147-156
• /
• 2001

Membership qualifications and recognition of the subspecialty training programs by the Korean Association of Pediatric Surgeons(KAPS) have been determined by criteria based on the number of neonatal and total pediatric surgical cases registered, since 1989 (Index cases). The numbers are based on a survey of the 14 founding members of the society by Jung et al. in 1987. The current survey is to review the present status of the index cases from 1997 to 1999 among 36 members of the KAPS. Two surveys were undertaken for this study. In the first survey, cases were collected by the registration form, composed of neonatal(N), important pediatric surgical cases (I), tumor and other similar operations(T) and other common pediatric surgical cases(O). Thirty members responded. and the result was discussed at the Topic Discussion section of the 15th Annual Congress of KAPS, 2000. The second survey analyzed additive data, proposed during discussion at the Congress. Twenty-three members responded. This report is the analysis of the both surveys. The average numbers of the cases/year/surgeon of N, I, T, O and total were 19.5, 51.8, 9.5, 77.1 and 356.5. respectively. The number of index cases(N+I+T)/year/surgeon was 80.8. The ratio of (N+I+T)/total cases was 0.3. Seventeen of 30 members have more than 20 cases of N per year. Twelve members have more than 150 cases, and 13 do more than 100 cases of I per year. Fourteen members have more than 10 cases of T per year. Nineteen and 10 members experienced more than 150 and 100 of index cases(N+I+T) per year. A new list of the index cases and coding system are proposed for the future regular update.

• Korean Journal of Social Welfare
• /
• v.68 no.2
• /
• pp.107-130
• /
• 2016

This study is aimed at the exploratory research on the influence of the obligation of extension of the retirement age on the baby boom generation. The basic question of this study is about which of the baby boom generation can get how much benefit according as the extension of the retirement age becomes compulsory. The extension of the retirement age is the system that can be applied to regular full-time workers. Accordingly, this study is intending to analyze the characteristics of the workers having a high likelihood for benefits from extension of the retirement age by tracing the economic activity state and labor history of the baby boomers. For this purpose, this study looked into the change of the economic activity state by age cohort of the male baby boomers based on the data for the Korea Labor Panel's 4th(2001) & 17th(2014)year. Using Survival analysis, this study also analyzed who will continue to remain as a regular full-time wage earner. As the result of the analysis, it was found that the more the cohort ages of baby boomers increased, the smaller the probability of remaining as a regular full-time wage earner, and the group who can get benefits from extension of the retirement age was predicted to account for only 11.4% level among the baby boomers. In addition, the result showed that there was a high likelihood of getting more benefits from extension of the retirement age when the baby boomers worked for the government-invested institution, corporate bodies, and government organizations rather than working for private enterprises. Thus, it can be safely said that there might appear a generational conflict due to extension of the retirement age in that such jobs coincide with the ones favored by the rising generation.

• Tuberculosis and Respiratory Diseases
• /
• v.47 no.5
• /
• pp.650-659
• /
• 1999

Background/Aims: It is well recognized that all aerobic cells have the protective mechanisms in order to minimize the tissue damage induced by various reactive oxygen species(ROS). Thioredoxin peroxidase(TPX) which has been recently identified and characterized functions to convert peroxide to water. The protein is also found in various subtypes(TPX-A & B, MER5, HS22 and HORF-06) and is known to be ubiquitous in most human cells. Especially, ischemic brain injuries, partial hepatectomy and radiation induced DNA damages. In treating lung cancer, radiation therapy has a major place in the local control and the relief of symptoms, but radiation induced free radical injury and resulting pulmonary fibrosis has been the major drawback of the therapy. However, little is known about the protective mechanisms and biologic modulations against radiation-induced tissue damages. Methods: Eighteen mice were divided into six groups, 3 in each group, and fifteen had received 900cGy of radiation. The mice were sacrificed according to the pre determined time schedule; immediate, 1, 2, 3 and 6 weeks after irradiation. Extracts were made from the lungs of each mice, Western blot analysis of various subtypes of TPX were done after SDS-P AGE. Examination of H & E stained slides from the same irradiated specimens and the control specimens were also performed. Results: No difference in the intensity of the immunoreactive bands in the irradiated lung samples of the mice compared to the unirradiated control was observed regardless of the time intervals, although H & E examination of the sample specimens demonstrated progressive fibrotic changes of the irradiated lung samples. Conclusion: In conclusion, according to our data, it is suggested that various thioredoxin peroxidase subtypes and catalase which are known to be increased in many repair processes may not be involved in the repair of the radiation injury to the lung and subsequent fibrosis.

• Tuberculosis and Respiratory Diseases
• /
• v.60 no.3
• /
• pp.277-284
• /
• 2006

Background : Delayed treatment of pulmonary tuberculosis is an important problem because it results in greater mortality and the nosocomial transmission of tuberculosis. This study was conducted to analyze the factors that contribute to the delayed treatment of pulmonary tuberculosis in a university hospital and we wanted to provide basic data for instituting an effective management program for tuberculosis. Methods : we retrospectively reviewed the medical records of 155 patients with smear-positive or culture-positive pulmonary tuberculosis and who were treated between May 1999 and October 1999. A case-control study was performed to analyze the factors. We then tried to follow up the patients in delayed treatment group via telephone for the purpose of assessing the therapeutic interventions. Results : Among 150 patients, 55 (37%) were included in the delayed treatment group. The factors associated with delayed treatment on the univariate analysis included age (61 vs 40 years old; p <0.001), a smear-negative sputum test for acid-fast bacilli (AFB) (85% vs 55%; p <0.001) and no visits to a private clinic before the patient presented to the university hospital (56% vs 36%; p = 0.014). Multivariate analysis revealed that old age (p = 0.001), a smear-negative sputum for AFB (p = 0.001), and lower lobe infiltrate on chest X-ray (p = 0.041) were the independent predictors of delayed treatment. Of the 22 patients who did not receive any treatment, 20 of them 91%) consented to our suggestion of revisiting the hospital. Conclusion : Delayed treatment of patients with pulmonary tuberculosis is not uncommon in a university hospital. Old age, smear-negative for AFB, and lower lobe infiltrate on chest X-ray are the risk factors for delayed treatment. A more systematic management system is required for achieving better control of tuberculosis.

• Journal of Bio-Environment Control
• /
• v.23 no.4
• /
• pp.293-302
• /
• 2014

This study was carried out to develop rain shelter which can make an appropriate size and environment for Chinese cabbage rainproof cultivation. Fifty three farms with chinese cabbage rainproof cultivation system have been investigated to set up width and height of rain shelter. Mostly the width of 6m was desired for rain shelter and the height of 1.6m for their eaves, so these values were chosen as the dimensions for rain shelter. After an analysis of their structural safety and installation costs by the specifications of the rafter pipe, Ø$25.4{\times}1.5t$ and 90cm have been set as the size of rafter that such size costs the least. This size is stable with $27m{\cdot}s^{-1}$ of wind velocity and 17cm of snow depth. Therefore it is difficult to apply this dimension to area with higher climate load. In order to sort out such problem, the rain shelter has been designed to avoid damage on frame by opening plastic film to the ridge. Once greenhouse band is loosen by turning the manual switch at the both sides of rain shelter and open button of controller is pushed then switch motor rises up along the guide pipe and plastic film is opened to the ridge. Chinese cabbage can be damaged by insects if rain shelter is opened completely as revealed a field. To prevent this, farmers can install an insect-proof net. Further, the greenhouse can be damaged by typhoon while growing Chinese cabbage therefore the effect of an insect-proof net on structural safety has been analyzed. And then structural safety has been analyzed through using flow-structure interaction method at the wind condition of $40m{\cdot}s^{-1}$. And it assumed that wind applied perpendicular to side of the rain shelter which was covered by insect-proof net. The results indicated that plastic film was directly affected by wind therefore high pressure occurred on the surface. But wind load on insect-proof net was smaller than on plastic film and pressure distribution was also uniform. The results of structural analysis by applying pressure data extracted from flow analysis indicated that the maximum stress occurred at the end of pipe which is the ground part and the value has been 54.6MPa. The allowable stress of pipe in the standard of structural safety must be 215 MPa or more therefore structural safety of this rain shelter is satisfied.

• Korean Journal of Rural Living Science
• /
• v.5 no.2
• /
• pp.135-144
• /
• 1994

This study was carried out to investigate health status and nutritional status based on dietary intake and food habit of elderly women in rural area of Keyonggi Province. The subject of this study were 133 elderly women aged 60 and over and interviewed with a questionaire. Main result was as follows : 1) Health score based on modified Cornell Medical Index, CMI(45 out of 195 items) was the average $29.1\pm6.8$ and was not significantly different with family size educational level and farmwork participation. In age, 44.0% of the subject in 60~65 years old was low score of CMI(11~25), but 50% of the subject in older than 80 years old was high score(33~44). The subject with disease was 82% and disease of musculoskeletal system was main type. 2) Dietary intake data obtained by a semiquantitative food frequency questionaire showed the average daily intake of energy, protein, Ca, retinol and riboflavin was lower than RDA Daily energy, protein and Ca intake was individually 84%, 67% and 55.1%. It was retinol that was the least sufficient as 49.1% of RDA. 3) The relation between CMI score(divided into three level : low, middle and high) showed low level was significantly different with others according to daily intake of energy, protein, retinol, thiamin, riboflavin and ascorbic acid. The correlation between CMI score and all nutrient intake were highly significant (p＜0.001), thus we knew that health status was affected importantly by nutrient intake. 4) Family size, educational level and age showed not significant correlation with all nutrient intake. 5) In food habit, 84.8% of the subject had regular mealtime and 14.4% were skip meal sometimes. The main reason of skip meal was a poor appetite. Preference for salty taste of subject was insufficiently salty of somewhat salty. Preference for fishes and meats showed the subject consumed fishes more than meats, but 23.5% of the subject didn't consume both. The subject eaten supplement was 38.3%.

• Progress in Medical Physics
• /
• v.26 no.4
• /
• pp.201-207
• /
• 2015

The new function of 3DVH software for dose calculation inside the patient undergoing TomoTherapy treatment by applying the measured data obtained by ArcCHECK was recently released. In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated by the comparison of measured dose distribution with the dose calculated using 3DVH. The 2D diode detector array MapCHECK phantom was used for the TomoTherapy planning of virtual patient and for the measurement of the compared dose. The average pass rate of gamma evaluation between the measured dose in the MapCHECK phantom and the recalculated dose in 3DVH was $92.6{\pm}3.5%$, and the error was greater than the average pass rate, $99.0{\pm}1.2%$, in the gamma evaluation results with the dose calculated in TomoTherapy planning system. The error was also greater than that in the gamma evaluation results in the RapidArc analysis, which showed the average pass rate of $99.3{\pm}0.9%$. The evaluated accuracy of 3DVH software for TomoTherapy DQA process in this study seemed to have some uncertainty for the clinical use. It is recommended to perform a proper analysis before using the 3DVH software for dose recalculation of the patient in the TomoTherapy DQA process considering the initial application stage in clinical use.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.2 no.3
• /
• pp.145-168
• /
• 2007

Current researches have been proceed on CEO's Characteristics of venture business because the CEO has considered as one of the important factors for the success of venture business. But prior research on the performance of venture business has produced inconsistently in terms of CEO's characteristics. The purpose of this study is to develop a comprehensive model for the relation between the performance and a type of CEO's characteristics by a growth process of venture business, which is the main subject of analysis in venture business. Also, this study analyzes various CEO's characteristics and the effects for performance of venture business which are in the Daedeok valley. To achieve the purpose of this research, an empirical study by using research model and hypotheses including the general characteristics of venture business and CEO's demographic characteristics has been presented as a research method for relation analysis. The principal findings of the research and its significance are summarized as follows: First, it was found that there is a significant different in the performance of CEO's behavioral characteristics by the scale, type and growing step of organization for venture business. Second, it was found that there is not a significant between an academic career, management experience, foundation experience for business and related working experience of venture CEO and the performance, but there os a partially significant difference in CEO's behavioral characteristics. Third, it was found that there is a partially significant difference between CEO's behavioral characteristics of venture business and the performance by the general characteristics of organization for venture business and demographic characteristics. In conclusion, in spite of the insufficient research for venture business in Daedeok, the implications of theses findings and contributions made by this research is to confirm the characteristics factor of CEO for venture business and general characteristics of organization for venture business by multidisciplinary side. In addition, the findings provide the basis for the analyzing of managerial strong point and weak point referred to supporting system for venture business. Finally, the findings of this study suggest that the results should be a useful data for groping a solution for upbringing plans in terms of a long-term point of view.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.15 no.2
• /
• pp.1-18
• /
• 2020

This study is to identify the influence of major variables that affect the participation intention of securities type crowdfunding investors and how participation intention and perceived behavioral control affect investors' herd behavior including indirect effect analysis based on the theory of planned behavior. The ultimate purpose of this study is to understand the investment behavior of securities type crowdfunding investors and to help the relevant parties to develop various policies and business plans to revitalize the system and protect investors. An online survey was conducted on people who are interested or have experience in securities type crowdfunding to receive a total of 276 responses. Excluding outliers, a total of 261 responses were taken into account for the final analysis. For the data analysis, structural equation model analysis using SPSS 22.0 and Amos 22.0 statistical package was conducted. As a result, two of the major variables of the theory of planned behavior-attitude and subjective norm-have been found to have a positive effect on the participation intention of securities type crowdfunding investors. And after analyzing the indirect effect, the participation intention was found to play a mediating role between attitude, subjective norm and herd behavior. However, the perceived behavioral control presented as a major variable of behavioral intention in the theory of planned behavior showed that the effect on participation intention was statistically insignificant. Instead, it was found to have a direct positive effect on herd behavior. This is significant because it empirically confirmed that even if investors perceive securities type crowdfunding as easy to participate, perceived behavioral control does not seem to have a significant impact on participation intention because securities type crowdfunding is an investment in an early-stage business with a high risk of loss. On the other hand, the study has great significance in that it empirically confirmed that domestic securities type crowdfunding investors perceive the funding progress information provided by the platform as a signal and imitate many other investors, showing herd behavior when they actually make an investment. It is expected that this study will provide meaningful insights for the policy making of crowdfunding supervisory offices and platform operators by empirically identifying major variables that influence the participation intentions and herd behavior of domestic securities type crowdfunding investors.