• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.3
• /
• pp.384-390
• /
• 2009

Extraction characteristics of citron (Citrus junos Sieb. ex Tanaka) seeds and functional properties of corresponding extract were monitored by response surface methodology (RSM). Maximum extraction yield of 20.23% was obtained at extraction temperature of $50.23^{\circ}C$, extraction time of 3.03 hr, and shaking velocity of 400.06 rpm. At extraction temperature, extraction time, and shaking velocity of $49.88^{\circ}C$, 2.72 hr, and 400.39 rpm, respectively, maximum polyphenol content was 4.37 mg/g. At extraction temperature, extraction time, and shaking velocity of $50.28^{\circ}C$, 3.42 hr, and 399.96 rpm, respectively, maximum electron donating ability (EDA) was 49.69%. Maximum nitrite scavenging activity (NSA) was 47.79% at extraction temperature, extraction time, and shaking velocity of $49.19^{\circ}C$, 0.68 hr, and 602.95 rpm, respectively. Based on superimposition of 3-dimensional RSM with respect to extraction yield, polyphenol, EDA, and NSA, optimum ranges of extraction conditions were extraction temperature of $50^{\circ}C$, extraction time of about 3 hr, and shaking velocity of 400 rpm.

• Journal of Gastric Cancer
• /
• v.5 no.3 s.19
• /
• pp.174-179
• /
• 2005

Purpose: The 5-year survival rate is the most useful parameter for evaluating the effect of management on most malignant tumors. Recurrence after a curative resection for gastric cancer occurs mostly within 3 years of the operation, which caused us to evaluate whether a 3-year disease-free survival (3DFS) can be substituted for a 5-year overall survival (5OS). Materials and Methods: We reviewed the medical records of 656 consecutive patients who had undergone a curative resection for gastric cancer To assess whether 3DFS represents 5OS, we used a simple linear regression with survival probability calculated by using the survival function. Results: Recurrence was found in 175 cases during the follow-up periods. The accumulative frequencies of recurrence at postoperative 1 year, 3 years, and 5 years were 46% (81 cases), 89% (156 cases), and 97% (170 cases), respectively. The correlation coefficient (r) and the coefficient of determination $(r^2)$ between 3DFS and 5OS were 0.87 and 0.76, respectively, and the regression equation was $5OS=0.18+(0.80{\times}3DFS)$. The r and $R^2$ according to the type of recurrence were 0.89 and 0.80 in peritoneal seeding, 0.88 and 0.78 in hematogeneous metastasis, and 0.86 and 0.73 in local recurrence, respectively. The r (0.77) and $r^2$ (0.60) were relatively lower in low stages (stage I and II) compared to r (0.88) and $r^2(0.77)$ in high stages (stage III and IV). Conclusion: The 3DFS is an excellent predictor of 5OS. Therefore, if we use the former as the treatment evaluating method, 2-year time reduction in assessing and reporting treatment results is expected.

• Journal of the Korean Society of Safety
• /
• v.7 no.2
• /
• pp.63-70
• /
• 1992

The aim of this research is to obtain a basic quantitative understanding of the effect of a noncondensable gas on the absorption of water vapor by a $H_2O$ / LiBr combination with n-octanol as the surfactant. Nonflowing aqueous solutions of LiBr (40,45,50 mass％) were exposed to saturated water vapor following the addition of an n-octanol sufactant (0.01 and 0.6 mass％). A small amount of a noncondensable gas (air) was allowed into the absorber (0.03 volume％) and its effect was analyzed by measuring the amount of water vapor absorbed. This study will aid to predict the performance of heat pump and safety operating condition when the noncondensable gas is not allowed in the absorber The results indicate that, in the presence of small amounts of a noncondensable gas, vapor absorption enhancement ratios are less than half o( those obtained under the same experimental conditions when a noncondensable gas is not present (1). The presence of a noncondensable gas causes the partial vapor pressure of air to increase at the vapor / liquid interface, which results in an instability of vapor absorption rate nd. hence, in an inhibition of interfacial disturbance.

• Korean Chemical Engineering Research
• /
• v.43 no.2
• /
• pp.206-214
• /
• 2005

Heterogeneously-catalyzed oxidation of aqueous phase trichloroethylene (TCE) over supported metal oxides has been conducted to establish an approach to eliminate ppm levels of organic compounds in water. A continuous flow reactor system was designed to effect predominant reaction parameters in determining catalytic activity of the catalysts for wet TCE decomposition as a model reaction. 5 wt.% $CoO_x/TiO_2$ catalyst exhibited a transient period in activity vs. on-stream time behavior, suggesting that the surface structure of the $CoO_x$ might be altered with on-stream hours; regardless, it is probable to be the most promising catalyst. Not only could the bare support be inactive for the wet decomposition reaction at $36^{\circ}C$, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Very low TCE conversion appeared for $TiO_2$-supported $NiO_x$ and $CrO_x$ catalysts. Wet oxidation performance of supported Cu and Fe catalysts, obtained through an incipient wetness and ion exchange technique, was dependent primarily on the kinds of the metal oxides, in addition to the acidic solid supports and the preparation routes. 5 wt.% $FeO_x/TiO_2$ catalyst gave no activity in the oxidation reaction at $36^{\circ}C$, while 1.2 wt.% Fe-MFI was active for the wet decomposition depending on time on-stream. The noticeable difference in activity of the both catalysts suggests that the Fe oxidation states involved to catalytic redox cycle during the course of reaction play a significant role in catalyzing the wet decomposition as well as in maintaining the time on-stream activity. Based on the results of different $CoO_x$ loadings and reaction temperatures for the decomposition reaction at $36^{\circ}C$ with $CoO_x/TiO_2$, the catalyst possessed an optimal $CoO_x$ amount at which higher reaction temperatures facilitated the catalytic TCE conversion. Small amounts of the active ingredient could be dissolved by acidic leaching but such a process gave no appreciable activity loss of the $CoO_x$ catalyst.

• Journal of dental hygiene science
• /
• v.11 no.6
• /
• pp.573-581
• /
• 2011

The purpose of this study was to examine the professionalism of dental hygienists in dental institutions and the influential factors for their professionalism in an attempt to seek ways of enhancing the professionalism of dental hygienists. The subjects in this study were 172 dental hygienists who worked in dental institutions in Busan and Gimhae. A self-administered survey was conducted to gather data, and an experimental analysis was carried out to analyze the collected data. The major findings of the study were as follows: First, concerning professionalism, self-regulation belief(3.70) ranked highest(3.42), followed by service belief(3.65), autonomy belief(3.31), a sense of vocational calling(3.30) and utilization of the professional organization as a standard(3.12). Second, the professionalism of the dental hygienists was significantly better when their title was higher, when they were older, when they got a larger monthly pay and when they intended to work for a longer time. Third, as for the influential factors for their professionalism, age, marital status, the estimated term of working at the workplace and opinion on reemployment were also identified as the significant variables that were up to the standard level of significance(p=0.05). The findings of the study suggest that in order to boost the professionalism of dental hygienists, it's required to take institutional measures to give them more responsibility, autonomy and authority, and how to improve personnel administration by providing strong motivation for them to look at their workplaces more favorably and keep on working for a long time should discreetly be considered.

• Journal of dental hygiene science
• /
• v.17 no.2
• /
• pp.142-149
• /
• 2017

This study targeted 123 dental hygienists working at the university and dental hospital as well as the dental clinic in Busan. The study ran for 5 months beginning July 23, 2016. The purpose of the study was to understand the relationship between core competencies and job performance for dental hygienists. The major core competencies of dental hygienists were interpersonal relation competency (3.61) was the highest, followed by management and educational competency (3.59), organizational relation competency (3.57), and basic dental hygiene management competency (3.56). Regarding the subjects' job performance, 'the task requested by a boss could be finished by the deadline' (3.93) was the highest, followed by 'there has been no case where others were harmed owing to carelessness' (3.76). 'The performance exceeding the targets set by the boss' (3.11) was relatively low. The group working for dental hospitals showed higher job performance than the group working for dental clinics (p=0.009) while there were high correlations between core competencies and job performance (p=0.733). Also, analysis for understanding relevant variables of core competencies that affected job performance revealed that the interpersonal relation competency (p=0.25), self-control competency (p=0.32), and basic dental hygiene competency (p=0.15) were significant. In summary, reinforcement of the dental hygienists' core competencies has a positive effect on job performance. Improved job performance in turn should improve patient care as well as the performance of the healthcare organization overall which will be eventually helpful to the provision of high-quality medical service to patients, and helpful for the hospital organization Helpful in making their performance better. Therefore, it would be necessary to establish administrative/educational support to facilitate dental hygiene education to develop major competencies and vocational basic abilities, as well as reinforce diverse competency educational programs for the current dental hygienists.

• Progress in Medical Physics
• /
• v.26 no.2
• /
• pp.93-98
• /
• 2015

The purpose of this study is to see the usefulness of lead apron for critical organs near the breast under examining. For clinical experiment, 30 female volunteers who agreed to their participation in the experiments, were chosen and divided into two groups, 15 in group A and 15 in group B respectively. group A is to see whether each side of breast under mammography affects to other side glandular on the critical organs is same, because it is not allowed to scan the both breast for same person or to scan repeatedly. Group B is to see the effectiveness of lead apron during the mammography of right breast. Glass dosimeters were placed on the thyroid, the contralateral breast, and lower abdomen where near the breast during examining. The average glandular doses on the surface in mammography of the thyroid gland, the contralateral breast, the lower abdomen were 0.0692 mGy, 0.6790 mGy, and 0.0122 mGy, respectively, which was an extremely low level of glandular dose. In group B, as to the thyroid gland, average dose was decreased from 0.0922 mGy to 0.0158 mGy. The average dose of contralateral breast was decreased from 0.8575 mGy to 0.0286 mGy. The average doses of lower abdomen was decrease 0.0150 mGy to 0.0173 mGy. As to the lower abdomen, dose decreased from 0.0150 mGy before the use of an apron down to 0.0173 mGy after the use. As p-value was under 0.05, statistically significant difference was observed between the two groups. Wearing an apron can have the protective effects on the thyroid gland up to 20 times lower than not wearing one. Besides, it is also necessary to protect the other breast during the examination by wearing one.

• Investigative Magnetic Resonance Imaging
• /
• v.13 no.1
• /
• pp.31-39
• /
• 2009

Purpose : This study proposes the keyhole method in order to improve the time resolution of the proton resonance frequency(PRF) MR temperature monitoring technique. The values of Root Mean Square (RMS) error of measured temperature value and Signal-to-Noise Ratio(SNR) obtained from the keyhole and full phase encoded temperature images were compared. Materials and Methods : The PRF method combined with GRE sequence was used to get MR temperature images using a clinical 1.5T MR scanner. It was conducted on the tissue-mimic 2% agarose gel phantom and swine's hock tissue. A MR compatible coaxial slot antenna driven by microwave power generator at 2.45GHz was used to heat the object in the magnetic bore for 5 minutes followed by a sequential acquisition of MR raw data during 10 minutes of cooling period. The acquired raw data were transferred to PC after then the keyhole images were reconstructed by taking the central part of K-space data with 128, 64, 32 and 16 phase encoding lines while the remaining peripheral parts were taken from the 1st reference raw data. The RMS errors were compared with the 256 full encoded self-reference temperature image while the SNR values were compared with the zero filling images. Results : As phase encoding number at the center part on the keyhole temperature images decreased to 128, 64, 32 and 16, the RMS errors of the measured temperature increased to 0.538, 0.712, 0.768 and 0.845$^{\circ}C$, meanwhile SNR values were maintained as the phase encoding number of keyhole part is reduced. Conclusion : This study shows that the keyhole technique is successfully applied to temperature monitoring procedure to increases the temporal resolution by standardizing the matrix size, thus maintained the SNR values. In future, it is expected to implement the MR real time thermal imaging using keyhole method which is able to reduce the scan time with minimal thermal variations.

• The korean journal of orthodontics
• /
• v.34 no.5 s.106
• /
• pp.371-379
• /
• 2004

The purpose of this study was to investigate the changes and types of statistical methods used in the Korean Journal of Orthodontics (KJO) and the American Journal of Orthodontics and Dentofacial Orthopedics (AJODO) from )999 to 2003. The frequency of use, transitions, assumption check of statistical methods and types of advanced statistical methods were examined from each journal. The study consisted of 247 articles published in the KJO and randomly chosen 50 articles per year which were original articles and used statistical methods T-test, analysis of variance(ANOVA), correlation analysis, nonparametric analysis. regression analysis chi-square test. factor analysis, were the order of statistical methods most frequently used in the KJO, while t-test. ANOVA, nonparametric analysis, correlation analysis, regression analysis, chi-square test. factor analysis. were the order of statistical methods used in the AJODO The changes of statistical methods observed in the KJO were not significant $(X^2=17.4\;p=0.5881)$ but the changes observed in the AJODO was seen to be significant $(x^2=42.4,\;p=0.0397)$ Some of the studies examined had overlooked the assumptions of the statistical methods employed. Data investigation such as outlier should be performed before analysis and alternative statistical approaches are applied for a small sample size. Types of advanced statistical methods were factor analysis and discriminant analysis in the KJO and Intention-To-Treat (ITT) analysis in clinical trials through multi-center, survival analysis and Generalized Estimating Equations (GEE) in the AJODO. Appropriate analysis approaches and interpretations should be applied for the correlated and repeated measurements of the orthodontic data set.

• Journal of Oral Medicine and Pain
• /
• v.31 no.3
• /
• pp.223-229
• /
• 2006

The objectives of this study was to investigate the amount of tooth ablation and the change of intrapulpal temperature by Er:YAG laser as it relates to pulse energy and pulse repetition rate at the identical power and, thereby, to reveal which of the two parameters strongly relates with ablation efficiency and intrapulpal temperature. Extracted healthy human molar teeth were sectioned into two pieces and each specimen was irradiated within the combination of pulse energy and pulse repetition time at the same power of 3W; $300mJy{\times}10Hz$ group, $200mJy{\times}15Hz$ group, and $150mJy{\times}20Hz$ group. Each specimen comprised ten tooth specimens. A laser beam with conjunction of a water flow rate of 1.6 ml/min was applied over enamel surfaces of the specimens during 3 seconds and the ablation amount was determined by difference in weight before and after irradiation. To investigate the temperature change in the pulp according to the above groups, another five extracted healthy human molar teeth were prepared. Each tooth was embedded into resin block and the temperature-measuring probes were kept on the irradiated and the opposite walls in the dental pulp during lasing. When the power was kept constant at 3W, ablation amount increased with pulse energy rather than pulse repetition rate (p=0.000). Although intrapulpal temperature increased with pulse repetition rate, there were no significant differences among the groups and between the irradiated and the opposite pulpal walls, except at a condition of $150y{\times}20Hz$ (p=0.033). Conclusively, it is suggested that ablation efficacy is influenced by pulse energy rather than pulse repetition rate.