• Journal of Pharmaceutical Investigation
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• 제37권4호
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• pp.211-216
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• 2007

The bark of Alnus japonica has been used for the treatment of fever, hemorrhage and diarrehea in oriental traditional medicine. Recently, it was revealed that the diarylheptanoids from the bark of Alnus japonica possess anti-inflammatory activity and are expected to be applicable for atopic dermatitis. In this study, oregonin, one of major active components in the bark of Alnus japonica, was developed in the form of semisolid formulations for topical delivery. Oregonin was incorporated into four ointment bases: O/W cream, W/O cream, hydrophilic ointment and lipophilic ointment. Oregonin release from all formulation prepared was evaluated. Franz cell method and immersion method were employed to characterize the release patterns of drug from each formulation based on solvent availability. O/W cream showed a better release profile than the other formulations when evaluated with Franz cell method with an order of O/W cream, hydrophilic ointment, W/O cream and lipophilic ointment. In the immersion method, hydrophilic ointment showed the greatest release rate at times 1 hour exceeding compared to other bases with an order of hydrophilic ointment, O/W cream, W/O cream and lipophilic ointment. Hydrophilicity and solvent availability of formulation seems to significantly influence the release rate of oregonin from ointment bases. In this study, we successfully characterized the oregon in ointment and found that o/w cream is a promising formulation for the topical delivery of oregonin.

• 대한치과보철학회지
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• 제29권2호
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• pp.17-22
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• 1991

The purpose of this study was to evaluate the tensile bond strengths of treated alloy surfaces for resin bonded retainers. For the experiment metal surfaces of 5 alloys were teated with sandblasting, Silicoating Rocatec, and cemented with Visio-Gem. All specimens divided into two groups. The group I specimens were treated with 24-hour immersion in $37^{\circ}C$ distilled water, and group II specimens were teated with 1500 thermo-cycles from $5^{\circ}C\;to\;55^{\circ}C$. The obtained results were as follows: 1. Bond strength values showed significantly different between sandblasting group and other groups after a 24-hour immersion in $37^{\circ}C$ distilled water(P<0.05). 2. All samples were fractured during thermo-cycles for sandblasting group, and bond strength values for Silicoating and Rocatec groups showed significantly different after 1500 thermo-cycles from $5^{\circ}C\;to\;55^{\circ}C$.

• Corrosion Science and Technology
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• 제21권1호
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• pp.41-52
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• 2022

Herein, we report polyvinyl butyral composites coatings containing various loadings of 72-h bath sonicated hexagonal boron nitride particles (5 ㎛) to enhance barrier properties of coatings. Barrier properties of coatings were determined in 3.5 wt% NaCl after different time periods of immersion via electrochemical techniques such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization test. Coatings containing sonicated hexagonal boron particles exhibited improved corrosion resistance for longer periods of immersion compared to neat coating. We also discussed effects of hexagonal boron nitride on healing properties of polyvinyl butyral. Coatings containing 1.0 wt% loading of sonicated hexagonal boron nitride showed improved long-term barrier properties than coatings with other compositions. The presence of hexagonal boron nitride also affected the healing properties of polyvinyl butyral coatings besides their barrier properties. Such improved barrier properties of composites coatings were attributed to the high aspect ratio, plate-like shape, and electrically insulated nature of the filler.

• 대한방사선기술학회지:방사선기술과학
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• 제45권6호
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• pp.515-522
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• 2022

The aim of the study was analyzed effect of the interaction with contents (IC), learning satisfaction (LS) and learning achievement (LA) through evaluation of the self-directed learning ability (SDLA) and immersion in learning (IL) for online learning application in the radiation therapy. A total of fifty university students who completed the radiation therapy course were be surveyed. There was significant positive correlation with the IC and the intention to continue using (ICU) in SDLA, and IC, LS, LA, and ICU in LC. The online learning application could be increase the satisfaction and achievement of radiation therapy learning.

• 공학교육연구
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• 제27권1호
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• pp.32-40
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• 2024

This study attempted to develop an efficient management plan that allows both workers and organizations to coexist by analyzing the factors that influence the level of organizational immersion of engineering students. Analysis methods included frequency analysis, t-test, pearson correlation analysis, and hierarchical analysis. Firstly, self-esteem and transfer of learning were influential factors on organizational commitment. Second, self-esteem and transfer of learning were influencing factors of self-efficacy. Third, self-efficacy was an influential factor in organizational commitment. Fourth, self-efficacy appeared as a mediating effect on self-esteem and organizational immersion in learning transfer. Therefore, it is necessary to look for various factors that can increase self-efficacy, and to find opportunities for students to be highly immersed in the organization while studying at the same time.

• The Journal of Advanced Prosthodontics
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• 제13권3호
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• pp.160-171
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• 2021

Purpose. This in-vitro study evaluated and compared the color stability of 3D-printed and conventional heat-polymerized acrylic resins following aging, mechanical brushing, and immersion in staining medium. Materials and methods. Forty disc-shaped specimens (10 mm in diameter and 3 mm thick) were prepared from two 3D-printed [DentaBASE (DB) and Denture 3D+ (D3D)] and one conventional polymethylmethacrylate (PMMA) denture materials. The specimens were thermo-cycled, subjected to mechanical brushing, and were immersed in either coffee, lemon juice, coke, or artificial saliva (AS) to simulate one and two years of oral use. Color measurements of the specimens were recorded by a spectrophotometer at baseline (T0), and after one (T1) and two years (T2) of simulation. The color changes (ΔE) were determined and also quantified according to the National Bureau of Standards (NBS) units. Descriptive statistics, followed by factorial ANOVA and Bonferroni post-hoc test (α=.05), were applied for data analysis. Results. The independent factors, namely material, staining medium, and immersion time, and interaction among these factors significantly influenced ΔE (P<.009). Irrespective of the materials, treatments, and time, the highest and the lowest mean ΔEs were observed for PMMA in lemon juice (4.58 ± 1.30) and DB in AS (0.41 ± 0.18), respectively. Regarding the material type, PMMA demonstrated the highest mean ΔE (2.31 ± 1.37), followed by D3D (1.67 ± 0.66), and DB (0.85 ± 0.52), and the difference in ΔE between the materials were statistically significant (P<.001). All the specimens demonstrated a decreased color changes at T2 compared to T1, and this difference in mean ΔE was statistically significant (P<.001). Conclusion. The color changes of 3D-printed denture resins were low compared to conventional heat polymerized PMMA. All the tested materials, irrespective of the staining medium used, demonstrated a significant decrease in ΔE values over time.

• International Journal of Oral Biology
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• 제34권3호
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• pp.137-142
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• 2009

Whole-body $\gamma$-irradiation(WBI), which produces an oxidative stress, is reported to attenuate the acute antinociceptive action of morphine (a $\mu$-opioid receptor agonist), but not DPLPE (a $\delta$-opioid receptor agonist), in mice. Recently, we also reported that antinociceptive effect of morphine, but not $\beta$-endorphin (a novel $\varepsilon$-opioid receptor agonist), was attenuated by oxidative stress. These findings prompted us to investigate the effect of WBI on the antinociception of morphine and $\beta$-endorphin in mice. Mice were exposed to WBI (5 Gy) from a $^{60}Co$ gamma-source and tested 2 hours later for antinociception produced by intracerebroventricular administration of morphine or $\beta$-endorphin using the hot water tail-immersion and the writhing tests. WBI significantly attenuated the antinociception produced by morphine only in the hot water tail-immersion test, whereas the antinociception of $\beta$-endorphin was significantly potentiated by WBI in both tests. These results demonstrate a differential sensitivity of $\mu$- and $\varepsilon$-opioid receptors to WBI, and support the hypothesis that morphine and $\beta$-endorphin administered supraspinally produce antinociception by different neuronal mechanisms.

• 한국치위생학회지
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• 제15권6호
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• pp.1091-1097
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• 2015

Objectives: The purpose of this study was to examine the relationship between educational satisfaction and learning participation of dental hygiene students. Method: A self-reported questionnaire was completed by 344 dental hygiene students in Gyeonggido, Chungcheongdo, and Gyeongsangdo from June 2 to 24, 2014, The questionnaire consisted of general characteristics of the subjects(3 items), choice reason of dental hygiene(7 items), educational satisfaction(22 items), and learning participation(11 items). The educational satisfaction and learning participation were assessed by Likert 5 points scale. Data were analyzed by a statistical package SPSS WIN 18.0. Results: Educational satisfaction included educational environments, teaching, educational content and educational effect. Learning participation included class flow, class participation and class readiness. Gyeongsangdo students tended to have higher score than other areas. The educational effect and teaching effect had more influence on learning participation. Conclusion: To improve the better dental hygiene education, it is important to prepare the effective educational methods and find out the influencing factors for class immersion.

• 농촌의학ㆍ지역보건
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• 제20권2호
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• pp.169-174
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• 1995

The case was described of a 31 year old female who developed fusiform swelling of the right third finger at the site of puncture by sea urchin spine. We observed a radiopaque linear material suggesting a remnant spine which the size was 2.4 mm in sonography and mammography. We confirmed that it exhibits a urchin spine and distinct caseous necrosis with central calcification. Sea urchins(Echinoidea) are ubiquitous marine creatures that resemble pincushions and are covered by calcareous skeletons surrounded by numerous movable calcium carbonate spines. The sharp spines are brittle and easily detach when touched by the victim. Contact with sea urchin spines produces intense pain, some localized erythema and edema. Inflammation develops in response to retained fragments. Granulomas 1-5 mm in diameter develop rarely 2-12 months after envenomation. In treatment, hot water immersion and thorough wound cleansing are advisable. Analgesics may, be necessary after hot water immersion. Attempts to remove these spines should be performed with good lighting sources, preferably with radiological direction. Chronic granulomas usually require complete excision. Acetone has been suggested for rapid resolution of pain. No antidotes are available.

• 치위생과학회지
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• 제23권1호
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• pp.20-28
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• 2023

Background: This study aimed to determine the effect of ramen sauce on tooth tone changes over time, after selecting three different ramen colors from the ramens sold in the market, and applying the sauce to bovine teeth. Methods: Healthy bovine teeth were selected, and cutting discs were used to produce 60 specimens (5× 5× 3 mm), with 15 specimens distributed per county. Three types of ramen (buldak, chacharoni black bean sauce, and ottogi curry noodle) were used as the experimental group, and water was used as the negative control group. Tooth tone measurement was performed using a spectrophotometer (CM-700d) to measure the color before and after 1 (3 h 44 min), 2 (7 h 28 min), 3 (11 h 12 min), and 4 weeks (14 h 56 min). Analysis of the color tone change was performed using Statistical Package for the Social Sciences version 28. Results: In the experimental group, there was a significant color tone change before and after immersion. L^* indicated the largest change in black bean sauce ramen, a^* indicated buldak ramen, and b^* indicated the largest change in curry ramen. The amount of color change (∆E^*) was the largest in curry ramen, followed by buldak and black bean sauce ramens. The results of the post-hoc analysis showed significant differences between all groups except buldak and black bean sauce ramens. Conclusion: All three types of ramen revealed significant color change before and after immersion, and curry ramen showed the largest amount of color change among them.