• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.67-73
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• 2014

Purpose: The purpose of present study is to compare mechanical properties and microstructural characteristics of fractured surface for cast, 3-D printing laser sintered and CAD/CAM milled cobalt-chromium (Co-Cr) alloy specimens and to investigate whether laser sintered technique is adequate for dental applications. Materials and methods: Thirty six flat disc shape Co-Cr alloy specimens were fabricated for surface hardness test and divided into three groups according to the manufacturing methods; 12 specimens for casting (n=12), 12 specimens for laser sintered technology (n=12) and 12 specimens for milled technology (n=12). Twelve dumbbell shape specimens for each group were also fabricated for a tensile test. Statistical comparisons of the mechanical properties for the alloys were performed by Kruskal-Wallis test followed by Mann-Whitney and Bonferroni test. The microstructural characteristics of fractured surfaces were examined using SEM. Results: There were significant differences in the mean Vickers hardness values between all groups and the cast specimen showed the highest (455.88 Hv) while the CAD/CAM milled specimen showed the lowest (243.40 Hv). Significant differences were found among the three groups for ultimate tensile strength, 0.2% yield stress, elongation, and elastic modulus. The highest ultimate tensile strength value (1442.94 MPa) was shown in the milled group and the highest 0.2% yield strength (1136.15 MPa) was shown in the laser sintered group. Conclusion: Different manufacturing methods influence the mechanical properties and microstructure of the fractured surfaces in Co-Cr alloys. The cast Co-Cr alloy specimens showed the highest Vickers hardness, and the CAD/CAM milled specimens revealed the highest tensile strength value. All alloys represent adequate mechanical properties satisfying the ISO standards of dental alloy.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.1
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• pp.1-6
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• 2020

Purpose: This study evaluated color stability of Dentca 3D-printed denture teeth, in comparison to color stabilities of four conventional types of denture teeth, upon being immersed in various colorants. Materials and methods: Four types of conventional prefabricated denture teeth (Surpass, GC, Artic 6, Heraeus Kulzer, Premium 6, Heraeus Kulzer, Preference, Candulor), 3D-printed denture teeth (Dentca); and Z250 (Filtek Z250, 3M ESPE) were prepared for testing. The samples were immersed in erythrosine 3%, coffee, cola, and distilled water (DW) at 37℃. Color change (ΔE) was measured by spectrophotometer before immersion and at 7, 14, and 21 days after immersion. One-way analysis of variance was performed along with Tukey's honestly significant difference multiple comparisons test (P<.05). Results: No great difference was observed between the color change of Dentca denture teeth and that of conventional denture teeth in most cases (P>.05). The color change of Dentca denture teeth immersed in erythrosine 3% was greater than that of Surpass (ΔE = 0.67 ± 0.25) after 1 week; Artic 6 (ΔE = 1.44 ± 0.38) and Premium 6 (ΔE = 1.69 ± 0.35) after 2 weeks; and Surpass (ΔE = 1.79 ± 0.49), Artic 6 (ΔE = 2.07 ± 0.21), Premium 6 (ΔE = 2.03 ± 0.75), and Preference (ΔE = 2.01 ± 0.75) after 3 weeks (P<.05). Conclusion: A color change was observed in Dentca denture teeth when immersed in some colorants; however, the maximum value of ΔE for Dentca denture teeth was within the clinically acceptable range.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.116-122
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• 2014

This study was conducted to find out the appropriate packaging materials to extend the storability and maintain the quality of cherry tomato for modified atmosphere (MA) storage. Tomatoes were grown by hydroponic at a plastic house in Gangwon Province. Light red maturity stage tomatoes were harvested and packed with MA condition (10,000; 20,000; 40,000; 60,000; 80,000; and $100,000cc/m^2.day.atm$ $O_2$ permeability film) and perforated film to store at $5^{\circ}C$, $11^{\circ}C$ and $24^{\circ}C$. The fresh weight loss was less than 0.6% in all non-perforated breathable films at $^5{\circ}C$, $11^{\circ}C$, and $24^{\circ}C$, but perforated film had less than 2.93% at $5^{\circ}C$, 13.29% at $11^{\circ}C$ and 27.24% at $24^{\circ}C$. The 20,000cc at $5^{\circ}C$ and $11^{\circ}C$, and the 40,000cc film at $24^{\circ}C$ balanced optimum carbon dioxide and oxygen concentration in the package to maintain quality. The 10,000cc film was appeared the significantly highest ethylene concentration at $5^{\circ}C$, $11^{\circ}C$, and $24^{\circ}C$, this film had the lowest $O_2$ permeability. Visual quality, firmness, and soluble solids were maintained in 20,000cc films both at $5^{\circ}C$ and $11^{\circ}C$, the 40,000cc film at $24^{\circ}C$. There was no any trend in titratable acidity and vitamin C content of treated packed film types and temperatures at cherry tomatoes packages. Therefore, the appropriate MA condition for $5^{\circ}C$ and $11^{\circ}C$ is $20,000cc/m^2.day.atm$ $O_2$ permeability film; for $24^{\circ}C$ it is $40,000cc/m^2.day.atm$ $O_2$ permeability film because those films extended the storability through the firmness, soluble solids as well as visual quality.

• Journal of Society of Preventive Korean Medicine
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• v.7 no.1
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• pp.17-28
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• 2003

We met results like the followings through the literatures and questionnaires about the tasks and solutions about the insurance fee of packed medical herbs. 1) It's turned out that 74.8% of herb doctors agrees to the insurance fee of packed medical herbs. However, in comparison with the same survey of the herb doctor association the percentage of general approval went somewhat lower, and especially the percentage of 'positive approval' became notably lower$(43.7%{\rightarrow}26.5%)$ and the percentage of 'active objection' raised about 2 times$(6.8%{\rightarrow}12.9%)$. Inquiring into the approval reasons on the insurance fee application of packed medical herbs some heads such as 'development toward treatment medical science' and 'decrease of publics burden' were higher than the one of 'management income and expenditure.' 2) As a result of the research, 36.0% of the patients and 42.8% of the residents recognized that the pay range of Chinese herb health insurance is narrow. They recognized that less people have the experiences of Chinese medical hospital use and internal application of the packed medical herbs as they are older, men rather than women. 85.4% of the patients and 74.9% of the residents agreed on the insurance pay of packed medical herbs. It's shown that they agree on the Chinese medical hospital use more as the economic standard is lower, on the insurance pay as they have ever taken the packed medical herbs. In the aspect of increase of insurance fee, 66.7% of the patients and 44.3% of the residents agreed on the insurance pay of packed medical herbs, and 18.1% and 36.1% disagreed on the insurance pay of packed medical herbs. The main objective reason why they disagree on the insurance pay of packed medical herbs was 'because the insurance fee goes up higher,' which answered 95.2% of the patients and 78.8% of the residents. 7.22% of the patients and 1.80% of the residents answered that they can pay more insurance fee in case of the insurance pay of packed medical herbs. However, in the priority order of the insurance pay, it hold the 5th position between 2 target research groups which was less than medical examination, charges for hospital accommodation and taking MRI. 3) According to the result of analysis about the cost of packed medical herbs, current practice price is 115,000 won and the average prime cost of a packed medical herb is 73,000 to 106,000 won. It's examined that the herb doctors regard that 95,000 won will be reasonable when the packed medical herb is payed in insurance. However, it was found out that the public generally thinks that the price would be appropriate on the level of 30,000 to 40,000 won and the percentage of the answers of 20,000 won to 30,000 was fairly high. 4) the central system of a prescription should be change into the central system of demonstration and the sick and wounded. 5) To solve this problem, the government should regulate it to pass by the circulation gradation of [importer, $peasantry{\rightarrow}manufacturer{\rightarrow}wholesaler{\rightarrow}distributor$(Chinese medical hospital, pharmacy dispensary of Chinese medicine)]And it should intervene into the quality and the circulation steps of Chinese medicine through 'the office or organization which is in charge of certification of Chinese medicine' and 'the office or organization which is in charge of the circulation of Chinese medicine.' And some actions such as simple severance, lavation, drying should be included into the conception of manufacture and the boundary between food and medical supplies should be made at a manufactory. And the regulation of standardized goods at one's own house should be improved so that, the peasantry can sell the materials of Chinese medicine only to the manufacturer. 6) In company with the insurance pay of packed medical herbs, the study about the separation of dispensary from medical practice in the Chinese medicine should be accomplished.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.2
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• pp.117-131
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• 2000

Objectives: To develop a new immunohistochemical marker system for supplementation of the Noyes histological classification of the endometrium in women of child bearing age with regular menstrual cycles, and to employ this system to evaluate pathologic factors involved in endometriosis, and thus to ascertain if it is useful in diagnosis. Materials and Methods: Endometrial biopsies were sampled from the posterior fundus of 41 (24 proliferative phases, 17 secretory phases) women with regular menstrual cycles (28-32 days), and each sample was immunohistochemically stained according to Noyes et al (1975) for determination of expression for estrogen receptor (ER), progesterone receptor (PR), integrin ${\alpha}_1$, ${\alpha}_4$, ${\beta}_3$, COX-1 and COX-2. Then, the PR, integrin ${\beta}_3$ and COX-2 which were clearly expressed in the luteal phase was with endometrial samples were obtained from 20 cases of normal patients (group 1) and 25 cases with endometriosis (group 2) after confirming the day of ovulation by sex steroid level measurements 7-8 days after ovulation Results: In the regular menstruation group the expression of ER showed a tendency to be increased in the proliferative phase and decreased in the secretory phase, and was the highest in the proliferative phase. However, PR in the stromal cells showed no change in the entire menstrual cycle while in the epithelial cells, PR reached a peak in the late proliferative phase and was almost absent in the secretory phase. Integrin (${\alpha}_1$, ${\alpha}_4$, and ${\beta}_3$ expression in the epithelial cells was absent in the proliferative phase but ${\alpha}_1$ was strongly expressed starting from the early secretory phase into the entire secretory phase. ${\alpha}_4$ was expressed strongly in the early and mid secretory phases and disappeared in the late proliferative phase, while ${\beta}_3$ appeared after the mid secretory phase and continued to be expressed until the late secretory phase. Expression in the stromal cells was weak overall and did not show any cyclic pattern. COX-1 expression was shown as a cyclic pattern in the stromal and epithelial cells and was particularly strongly expressed in the mid secretory phase of epithelial cells, and in the mid secretory and menstruation phase of stromal cells. In the endometrial epithelial cells there was strong expression during the entire cycle with stronger expression in the secretory phase compared to the prolferative phase. COX-2 was clearly expressed in the late proliferative, early and mid secretory phases in the stromal cells. No expression was observed in the proliferative phase of the epithelial cells, but which began to appear in the early secretory phase reaching a significant pattern from the mid secretory phase onwards. There was almost no expression in the stromal cells. In the cases with endometriosis showing normal endometrial maturation according to the Noyes classification, PR expression was increased while Integrin-${\beta}_3$의 expression was significantly decreased compared to the normal group. Also, COX-2 expression was slightly decreased in the stromal cells of patients with endometriosis while it was significantly increased in the stromal cells. Conclusion: Immunohistochemical markers can supplement the original Noyes classification of histological endometrial dating and therefore ascertain existing pathologic conditions. Particularly for patients with endometriosis with normally mature endometrial cells, changes in COX-2 and integrin expression patterns may assist in elucidating pathophysiologic mechanisms and therefore aid in the diagnosis of abnormal implantation conditions, and consequently determine a treatment modality.

• Korean Journal of Plant Resources
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• v.30 no.5
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• pp.522-534
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• 2017

This study was investigated genetic variation in 24 Taraxacum accessions from various regions in South Korea based on the sequences of two chloroplast DNA (cpDNA) regions (trnL-trnF and rps16-trnK). T. mongolicum, T. officinale, and T. laevigatum were triploid, and T. coreanum and T. coreanum var. flavescens were tetraploid. The trnL-trnF region in native Korean dandelions (T. mongolicum, T. coreanum, and T. coreanum var. flavescens) were ranged from 931 to 935 bp in length, and that of naturalized dandelions were ranged from 910 bp (T. officinale) to 975 bp (T. laevigatum) in length. The rps16-trnK region in T. mongolicum, T. coreanum, T. coreanum var. flavescens, T. officinale, and T. laevigatum was 882-883 bp, 875-881 bp, 878-883 bp, 874-876 bp, and 847-876 bp, respectively, in length. The sequence similarity matrix of the trnL-trnF region ranged from 0.860 to 1.00 with an average of 0.949, and that of the rps16-trnK region ranged from 0.919 to 1.000 with an average of 0.967. According to the phylogenetic analysis, the Korean native taxa and naturalized taxa were divided independent clade in two cpDNA region. T. coreanum var. flavescens clustered only with T. coreanum, and there were no significant differences in their nucleotide sequences. The finding that two accessions (T. coreanum; Jogesan, T. mongolicum; Gangyang) had a high level of genetic variation suggests their utility for breeding materials.

• Journal of Korean society of Dental Hygiene
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• v.9 no.4
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• pp.753-767
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• 2009

Objectives : The study is to gain some basic material for the improvement of dental clinics' homepages through a survey investigation, in which college students of three Dental Hygienic departments participated in Kwangju and Cheollanamdo Province. Methods : In the investigation three factors were analyzed : the degree of knowledge on dental clinics' homepages, the degree of recognition on them, and whether they have paid a visit on them or not. A total of 509(96.8%) respondents are valid except 17sheets of responses. Results : 1. When asked about the degrees of knowledge on the formation of the homepages by students' years, the correct rate on Information Service was higher in a row of the second year, the first year, and the third year. And it shows statistically significant difference(p<0.05). In the part of Counseling Service, the rate of correct answers was highest in the second year, and then the first year and the third year. It also shows significant difference(p<0.05). In case of Visual Service, the second year got the highest rate of correct answers, and then the first year and the third year. Here is significant difference by the school years<0.01) 2. It was asked whether they have visited the dental clinics' homepages. The results are like this: 145 sophomores(28.5%) have visited them, and 115 juniors(22.6%) and 85 freshmen(16.7%), and it show significant difference (p<0.001). 3. It was asked how many sites they have visited. Among the freshmen, not a few students visited two sites (34, 9.9%), among sophomores 48 students visited five sites(13.9%), and among juniors the highest answers were two sites (41, 11.9%). It shows signigicant difference(p<0.01). 4. It was asked what is the purpose of the visits. At this 27 freshmen answered for having counseling(7.8%), and 80 sophomores(23.3%) and 43 juniors(12.5%) answered they visited them for the purpose of gaining some materials about their major. It shows significant difference(p<0.001). 5. It was asked with what opportunity they have visited them. They answered through searching activities like this : freshmen (68, 19.8%), sophomores (130, 37.9%), and juniors (98, 28.6%). It shows significant difference(p<0.05). 6. In regard with the recognition of the homepages, all the participants said that the management of the homepages are closely related with the images of the clinics($3.96{\pm}0.781$). But it is found that they do not think that the effective management of dental clinics' homepages is the task of dental hygienic workers as a part of dental hygienic($3.12{\pm}0.971$). 7. There is some difference concerned with the homepages among each group of students; sophomores have highest recognition on them and then juniors and freshmen, and it shows significant difference(p<0.01). In addition, those who have visited them show higher recognition than those who have never visited them(p<0.001). Conclusions : There are some differences among each group of students in regard with the formation service, the purpose of visiting them and such experiences, and the opportunities. Whereases they think that the management of the homepages are closely related with the images of the clinics, they do not think that the effective management of dental clinics' homepages is the task of dental hygienic workers as a part of dental hygienic. Therefore it is necessary to study actively for the qualitative improvement of the dental clinics' homepages, which will result in the higher recognition on the homepages by the dental hygienic students and the workers.

• Korean Journal of Head & Neck Oncology
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• v.23 no.2
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• pp.153-156
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• 2007

Objectives : We study the feasibility and pharmacokinetics of cisplatin concurrent chemoradiation for advanced head and neck cancer patient undergoing hemodialysis. Materials and Methods : A 57-year old male with end stage renal disease developed stage III external auditory canal cancer. Complete resection surgery was done. Postoperative 6 months, local recurrence was occurred. Despite excision and adjuvant radiotherapy, local tumor was recurred. We decided to treat a cisplatin concurrent chemoradiotherapy. Cisplatin was administered at a dose of $20mg/m^2$ for 30 min. Hemodialysis was started 30 min after completion of the cisplatin infusion and performed for 4 hours. Hemodialysis was performed on day 3 and 5 of chemotherapy. Plasma samples were collected at specified times after administration of cisplatin. Result : At the end of the third cycle of cisplatin concurrent chemoradiotherapy, the tumor size was markedly decreased. The maximum plasma concentrations of plasma platinum and free platinum were 0.74 and $0.37{\mu}g/ml$ respectively. The area under the curve of plasma platinum and free platinum were 94.7 and $11.3{\mu}g{\cdot}h/ml$ respectively. Conclusion : We report a case of Cisplatin concurrent chemoradiation for hemodialysis patient with advanced head and neck cancer and suggest full dose cisplatin concurrent chemoradiotherpay is tolerable for these patients.

• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.304-313
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• 2016

One of the issues currently facing nuclear power plants is how to store spent nuclear waste materials which are contaminated with radionuclides such as $^{134}Cs$, $^{135}Cs$, and $^{137}Cs$. Bioremediation processes may offer a potent method of cleaning up radioactive cesium. However, there have only been limited reports on $Cs^+$ tolerant bacteria. In this study, we report the isolation and identification of $Cs^+$ tolerant bacteria in environmental soil and sediment. The resistant $Cs^+$ isolates were screened from enrichment cultures in R2A medium supplemented with 100 mM CsCl for 72 h, followed by microbial community analysis based on sequencing analysis from 16S rRNA gene clone libraries(NCBI's BlastN). The dominant Bacillus anthracis Roh-1 and B. cereus Roh-2 were successfully isolated from the cesium enrichment culture. Importantly, B. cereus Roh-2 is resistant to 30% more $Cs^+$ than is B. anthracis Roh-1 when treated with 50 mM CsCl. Growth experiments clearly demonstrated that the isolate had a higher tolerance to $Cs^+$. In addition, we investigated the adsorption of $0.2mg\;L^{-1}$ $Cs^+$ using B. anthracis Roh-1. The maximum $Cs^+$ biosorption capacity of B. anthracis Roh-1 was $2.01mg\;g^{-1}$ at pH 10. Thus, we show that $Cs^+$ tolerant bacterial isolates could be used for bioremediation of contaminated environments.

• Science of Emotion and Sensibility
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• v.16 no.1
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• pp.125-132
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• 2013

Recently, the consciousness of energy crisis is rapidly growing and sustainable eco-friendly energy sources are becoming issue. Therefore the portable electronic device requires new energy sources for providing continuous power supply and the power energy harvesting system of the human body that enables the power-harvesting research requests anytime, anywhere. One of the sources for energy harvesting is heat energy, which is the difference in temperature of the body and the surrounding environment. We tried to analyze the temperature difference between the environmental temperature and the temperature inside clothing according to the structure of the closed portion. And we examined the temperature difference between the environmental temperature and the temperature inside clothing according to the material of the clothing. The analysis showed that we have been able to get different results at parts of the body in the temperature inside clothing according to the structure of clothing. In upper torso of the chest and back, the temperature inside clothing of 'closed structure' was higher than the temperature inside clothing of 'opened structure'. In the section of arm and leg, it was reduced the difference of temperature inside clothing between 'closed structure' and 'opened structure'. It was particularly noticeable in the section of leg. The results of analysis of the difference between the environmental temperature and the temperature inside clothing according to the material of the clothing, in both cases of the two materials, 'closed structure' was higher than the 'opened structure' in the difference value between the environmental temperature and the temperature inside clothing. There was a difference according to the material in the section of leg. In this study, we outlined the basic guidelines for developing heat energy harvesting clothing by exploring the structure and material of clothing suitable for the heat energy harvesting.