104 research outputs found

    THE EFFECT OF THE SUPERSATURATED SOLUTIONS CONTAINING HIGH CONCENTRATIONS OF FLUORIDE ON SEEDED CRYSTAL GROWTH

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    In biological systems, the mineral that forms hard tissue is of an apatitic nature, and hydroxyapatite(Ca5OH(PO4)3Ca_5OH(PO_4)_3: HA) is generally considered as the prototype for such a mineral. Thus, the precipitation of HA, having biological implications, has been the subject of several investigations. Crystal growth studies using HA seeds in supersaturated solutions have enhanced our understanding of the process and mechanism involved in seeded crystal growth. From these studies, it has become apparent that the precipitation rate of HA onto the seed crystals depends on the various conditions, especially on the additives. The relation between the supersaturated solution containing fluoride and the process of HA crystal growth enhances the understanding of mechanism of HA crystal growth. Until recently, the studies have been on the crystal growth of enamel minerals and synthetic HA seeds in the supersaturated solution containing 1~2 ppm fluoride. The purpose of the present investigation is to study the effect that fluoride of high concentration has on the crystal growth kinetics of HA. In order to produce the composition found in the secretory enamel fluid, experimental solutions of 1mM Ca, 3mM P, and 100mM Tris as background electrolyte were used. Then this experimental solutions were added to 0, 2, 4, 6, 8, 10 ppm fluoride. The effect of fluoride at high concentrations on the precipitation was examined in a bench-top crystal growth model adopting a miniaturized reaction column. Chemical analysis was employed for characterization of working solutions before and after the experimentation. Remarkable findings were : 1) the amount of crystal growth was gradually accelerated as the fluoride concentration increased until 6 ppm, but decreased in 8 and 10 ppm fluoride; 2) the amount of fluoride ion consumed in crystal formation was constant despite the increase in fluoride concentration.ope

    An Integrated Humanities-Social Sciences Course in Health Sciences Education: Proposed Design, Effectiveness, and Associated Factors

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    Background: Previous research has not provided enough direction regarding effective content design of courses integrating the humanities and social sciences in medical and dental education. This study aims at exploring how an Integrated Medical/Dental Humanities-Social Medicine/Dentistry course may be designed; how effective it may be in terms of student growth in knowledge, attitudes, skills, and aspirations; and associated factors. Methods: The course was designed by distilling commonalities in the international standards for medical/dental education proposed by seven major health organizations. This analysis resulted in a curriculum covering nine major topics: history, professionalism, communication, ethics, management, policy, insurance, law, and research methodology. During the 2017 calendar year, data was collected and statistically analyzed from 68 third-year pre-doctoral students enrolled in the resulting MDHS 13-week course. Results: Participants showed growth in skills, aspirations, knowledge, and attitudes, with the greatest change occurring in skills, then aspirations, knowledge, and attitudes. Knowledge growth was the only variable significantly related to student achievement of course objectives (ฮฒ = 0.635, t (63) = 3.394, p = 0.001). The topics that students perceived as most critical were insurance, policy, management, and law. The perceived importance of research was most common among participants and was significantly related to all learning outcomes (For knowledge, ฮฒ = 0.213, t (63) = 2.203, p = 0.031; for attitudes, ฮฒ = 0.784, t (63) = 10.257, p = 0.000; for skills, ฮฒ = 0.769, t (63) = 9.772, p = 0.000; and aspirations ฮฒ = 0.639, t (63) = 7.595, p = 0.000). Conclusions: This study proposed a framework for humanities-social sciences education in health sciences education and analyzed its implementation. The empirical evaluation of its effectiveness and factors related to successful outcomes found that students perceived gains in their knowledge, attitudes, skills, and aspirations for humanistic and social aspects of dentistry/medicine. In addition, their recognition of the importance of research was associated with the greatest growth in all four learning outcomes. This study may contribute to the improved design of integrated humanities-social sciences courses.ope

    Characteristics of Solar Desalination System Using Refrigerant As a Heating Source

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    The evaporative desalination system using solar thermal energy would be very efficient and attractive method to get fresh water from brine due to low carbon dioxide generation. In this research the solar desalination system as a heating source of refrigerant R123 and R141b in the evaporator was considered. The circulation of refrigerant in the evaporator can reduce the energy consumption of the system, through using the latent heat of the refrigerant instead of the sensible heat of present warm water. The system was composed of the single-stage fresh water production unit of 1 ton/day capacity with shell and tube type evaporator, heaters instead of solar collector for supplying proper heat to refrigerant, and refrigerant circulation system. Various operating flow rate and temperature ranges were imposed on the experiments to get the optimum design data. The experimental results showed that the optimum flow rate of brine feed to evaporator was 1.2Liter/min of R123 and 1.0Liter/min of R141b, and the yield of fresh water increased with brine temperature rise. It was confirmed that the flow rate of heating source of refrigerant as heating source decreased down to one fifth that of the present warm water system, and it was proven to be very efficient system for solar desalination.์ œ 1 ์žฅ ์„œ ๋ก  1 1.1 ์—ฐ๊ตฌ ๋ฐฐ๊ฒฝ 1 1.2 ์—ฐ๊ตฌ ๋ชฉ์  4 1.3 ์„ ํ–‰์—ฐ๊ตฌ ์กฐ์‚ฌ 6 ์ œ 2 ์žฅ ์ด๋ก ์  ๋ฐฐ๊ฒฝ 8 2.1 ํ•ด์ˆ˜ ๋‹ด์ˆ˜ํ™” ๊ธฐ์ˆ  8 2.1.1 ๋‹ค๋‹จ ํ”Œ๋ž˜์‹œ ์ฆ๋ฐœ๋ฒ• 9 2.1.2 ๋‹ค์ค‘ ํšจ์šฉ ์ฆ๋ฐœ๋ฒ• 10 2.2 1๋‹จ ์ฆ๋ฐœ๋ฒ• ๊ณต์ • 12 2.2.1 ๋‹ด์ˆ˜๊ธฐ ๊ตฌ์กฐ ๋ฐ ์šด์ „ ํŠน์„ฑ 12 2.2.2 1๋‹จ ์ฆ๋ฐœ๋ฒ• ์šด์ „ ์กฐ๊ฑด 14 2.3 ๋ƒ‰๋งค ์ ์šฉ ๋‹ด์ˆ˜ ์‹œ์Šคํ…œ 16 2.3.1 ์‹œ์Šคํ…œ ํŠน์ง• 16 2.3.1.1 ๋ƒ‰๋งค ์ ์šฉ ๋‹ด์ˆ˜์‹œ์Šคํ…œ์˜ ์žฅ์  16 2.3.1.2 ๋ƒ‰๋งค ์ ์šฉ ๋‹ด์ˆ˜์‹œ์Šคํ…œ์˜ ๋‹จ์  17 2.3.2 ๋ƒ‰๋งค ์ ์šฉ ์‹œ์Šคํ…œ 18 2.4 ์ ์šฉ ๋ƒ‰๋งค์˜ ํŠน์ง• 20 2.4.1 ์ƒ๋ณ€ํ™” ์˜จ๋„์™€ ์••๋ ฅ 20 2.4.2 ์ฆ๋ฐœ ์ž ์—ด๊ณผ ์ฆ๊ธฐ ๋ฐ ์•ก์ฒด์˜ ํ˜„์—ด 23 2.4.3 ๋ฐ€๋„ 25 2.5 ๋ฌผ์˜ ์ฆ๋ฐœ ์˜จ๋„ 26 2.6 ๋ƒ‰๋งค ์ฆ๋ฐœ๊ธฐ ์—ด๊ตํ™˜๊ธฐ ์„ค๊ณ„ 27 2.6.1 ๋ƒ‰๋งค R123 ์ ์šฉ ์‹œ ์ฆ๋ฐœ๊ธฐ ์—ด ๊ตํ™˜ ๋ฉด์  ์‚ฐ์ • 27 2.6.1.1 ๊ด€ ๋‚ด๋ถ€ ์‘์ถ• ์—ด์ „๋‹ฌ๊ณ„์ˆ˜ ์‚ฐ์ • 27 2.6.1.2 ๊ด€ ์™ธ๋ถ€ ์ฆ๋ฐœ ์—ด์ „๋‹ฌ๊ณ„์ˆ˜ ์‚ฐ์ • 28 2.6.1.3 R123 ๋ƒ‰๋งค ์ฆ๋ฐœ๊ธฐ ์—ด๊ตํ™˜ ๋ฉด์  29 2.6.2 ๋ƒ‰๋งค R141b ์ ์šฉ ์‹œ ์ฆ๋ฐœ๊ธฐ ์—ด ๊ตํ™˜ ๋ฉด์  ์‚ฐ์ • 30 2.6.2.1 ๊ด€ ๋‚ด๋ถ€ ์‘์ถ• ์—ด์ „๋‹ฌ๊ณ„์ˆ˜ ์‚ฐ์ • 30 2.6.2.2 ๊ด€ ์™ธ๋ถ€ ์ฆ๋ฐœ ์—ด์ „๋‹ฌ๊ณ„์ˆ˜ ์‚ฐ์ • 30 2.6.2.3 R141b ๋ƒ‰๋งค ์ฆ๋ฐœ๊ธฐ ์—ด๊ตํ™˜ ๋ฉด์  30 2.7 ์‘์ถ•๊ธฐ ์—ด๊ตํ™˜๊ธฐ ์„ค๊ณ„ 32 2.8 ํƒœ์–‘์—ด ์ง‘์—ด๊ธฐ ์ง‘์—ด๋ฉด์  33 ์ œ 3 ์žฅ ์‹คํ—˜์žฅ์น˜ ๋ฐ ์‹คํ—˜๋ฐฉ๋ฒ• 34 3.1 ๋‹ด์ˆ˜๊ธฐ ์ œ์ž‘ 34 3.1.1 ๋‹ด์ˆ˜๊ธฐ ๋ณธ์ฒด 34 3.1.2 ์ฆ๋ฐœ๊ธฐ ๋ฐ ์‘์ถ•๊ธฐ ์„ค๊ณ„ 36 3.1.2.1 ์ฆ๋ฐœ๊ธฐ ์„ค๊ณ„ 36 3.1.2.2 ์‘์ถ•๊ธฐ ์„ค๊ณ„ 36 3.1.3 ์‘์ถ•๊ธฐ ์œ ๋กœ ํ•ด์„ 39 3.1.4 ์ด์ ํ„ฐ ์„ฑ๋Šฅ ํ•ด์„ 42 3.2 ์‹คํ—˜ ์žฅ์น˜ 46 3.3 ์‹คํ—˜ ๋ฐฉ๋ฒ• 53 ์ œ 4 ์žฅ ์‹คํ—˜๊ฒฐ๊ณผ ๋ฐ ๊ณ ์ฐฐ 54 4.1 ๋ƒ‰๋งค R123 ์ ์šฉ ์‹œ ์‹คํ—˜ ๊ฒฐ๊ณผ 54 4.1.1 Orifice ์œ ๋ฌด์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 54 4.1.2 ์ฆ๋ฐœ๊ธฐ ํ•ด์ˆ˜ ์ฃผ์ž…๋Ÿ‰์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 55 4.1.3 ์ฆ๋ฐœ๊ธฐ ์ž…๊ตฌ ๋ƒ‰๋งค ์˜จ๋„์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 58 4.1.4 ์ฆ๋ฐœ๊ธฐ ํ•ด์ˆ˜ ์œ ์ž… ์˜จ๋„์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 58 4.1.5 ๋ƒ‰๋งค R123 ์ ์šฉ ์‹คํ—˜ ๊ฒฐ๊ณผ ๋ถ„์„ 61 4.2 ๋ƒ‰๋งค R141b ์ ์šฉ ์‹œ ์‹คํ—˜ ๊ฒฐ๊ณผ 63 4.2.1 ์ฆ๋ฐœ๊ธฐ ํ•ด์ˆ˜ ์ฃผ์ž…๋Ÿ‰์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 63 4.2.2 ์ฆ๋ฐœ๊ธฐ ์ž…๊ตฌ ๋ƒ‰๋งค ์˜จ๋„์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 63 4.2.3 ์ฆ๋ฐœ๊ธฐ ํ•ด์ˆ˜ ์œ ์ž… ์˜จ๋„์— ๋”ฐ๋ฅธ ๋‹ด์ˆ˜ ์ƒ์„ฑ๋Ÿ‰ 65 4.2.4 ๋ƒ‰๋งค R141b ์ ์šฉ ์‹คํ—˜ ๊ฒฐ๊ณผ ๋ถ„์„ 67 ์ œ 5 ์žฅ ๊ฒฐ๋ก  69 ์ฐธ ๊ณ  ๋ฌธ ํ—Œ 7

    Identification of Porphyromonas gingivalis genes specifically expressed in human gingival epithelial cells by using differential display reverse transcription-PCR

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    Porphyromonas gingivalis, one of the causative agents of adult periodontitis, can invade and survive within host epithelial cells. The molecular mechanisms by which P. gingivalis induces uptake and adapts to an intracellular environment are not fully understood. In this study, we have investigated the genetic responses of P. gingivalis internalized within human gingival epithelial cells (GECs) in order to identify factors involved in invasion and survival. We compared the differential display of arbitrarily PCR-amplified gene transcripts in P. gingivalis recovered from GECs with the display of transcripts in P. gingivalis control cultures. Over 20 potential differentially expressed transcripts were identified. Among these, pepO, encoding an endopeptidase, and genes encoding an ATP-binding cassette (ABC) transporter and a cation-transporting ATPase were upregulated in GECs. To investigate the functionality of these gene products, mutants were generated by insertional inactivation. Compared to the parental strain, mutants of each gene showed a significant reduction in their invasion capabilities. In addition, GEC cytoskeletal responses to the mutants were distinct from those induced by the parent. In contrast, adhesion of the mutant strains to GECs was not affected by lack of expression of the gene products. These results suggest that PepO, a cation-transporting ATPase, and an ABC transporter are required for the intracellular lifestyle of P. gingivalis.ope

    Differential Protein Expression by Porphyromonas gingivalis in Response to Secreted Epithelial Cell Components

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    The human oral pathogen Porphyromonas gingivalis colonizes the gingival crevice and invades gingival epithelial cells. Multi-dimensional capillary HPLC coupled with tandem mass spectrometry and 2D gel electrophoresis were used to analyze the proteome of P. gingivalis as it adapts to a set of experimental conditions designed to reflect important features of an epithelial cell environment. 1014 proteins (46% of the total theoretical proteome) were identified in four independent analyses. 479 of these proteins showed evidence of differential expression after exposure of P. gingivalis to either conditioned epithelial cell growth medium or control conditions: i.e. they were only detected under one set of conditions. Moreover, 276 genes annotated as hypothetical were found to encode expressed proteins. Among the proteins upregulated in the presence of epithelial cell components were a homolog of the internalin proteins of Listeria monocytogenes and subunits of the ATP-dependent Clp protease complex. Insertional inactivation of clpP, encoding the Clp proteolytic subunit, resulted in an approximately 50% reduction in invasion of P. gingivalis. These results suggest that adaptation to an epithelial cell environment induces a major shift in the expressed proteome of the organism. Furthermore, ClpP, that is upregulated in this environment, is required for optimal invasive activity of P. gingivalis.ope

    ๊ณ ์œ  ํŠน์„ฑ์„ ํ™œ์šฉํ•œ ์Œ์•…์—์„œ์˜ ๋ณด์ปฌ ๋ถ„๋ฆฌ

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์œตํ•ฉ๊ณผํ•™๊ธฐ์ˆ ๋Œ€ํ•™์› ์œตํ•ฉ๊ณผํ•™๋ถ€, 2018. 2. ์ด๊ต๊ตฌ.๋ณด์ปฌ ๋ถ„๋ฆฌ๋ž€ ์Œ์•… ์‹ ํ˜ธ๋ฅผ ๋ณด์ปฌ ์„ฑ๋ถ„๊ณผ ๋ฐ˜์ฃผ ์„ฑ๋ถ„์œผ๋กœ ๋ถ„๋ฆฌํ•˜๋Š” ์ผ ๋˜๋Š” ๊ทธ ๋ฐฉ๋ฒ•์„ ์˜๋ฏธํ•œ๋‹ค. ์ด๋Ÿฌํ•œ ๊ธฐ์ˆ ์€ ์Œ์•…์˜ ํŠน์ •ํ•œ ์„ฑ๋ถ„์— ๋‹ด๊ฒจ ์žˆ๋Š” ์ •๋ณด๋ฅผ ์ถ”์ถœํ•˜๊ธฐ ์œ„ํ•œ ์ „์ฒ˜๋ฆฌ ๊ณผ์ •์—์„œ๋ถ€ํ„ฐ, ๋ณด์ปฌ ์—ฐ์Šต๊ณผ ๊ฐ™์ด ๋ถ„๋ฆฌ ์Œ์› ์ž์ฒด๋ฅผ ํ™œ์šฉํ•˜๋Š” ๋“ฑ์˜ ๋‹ค์–‘ํ•œ ๋ชฉ์ ์œผ๋กœ ์‚ฌ์šฉ๋  ์ˆ˜ ์žˆ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์˜ ๋ชฉ์ ์€ ๋ณด์ปฌ๊ณผ ๋ฐ˜์ฃผ๊ฐ€ ๊ฐ€์ง€๊ณ  ์žˆ๋Š” ๊ณ ์œ ํ•œ ํŠน์„ฑ์— ๋Œ€ํ•ด ๋…ผ์˜ํ•˜๊ณ  ๊ทธ๊ฒƒ์„ ํ™œ์šฉํ•˜์—ฌ ๋ณด์ปฌ ๋ถ„๋ฆฌ ์•Œ๊ณ ๋ฆฌ์ฆ˜๋“ค์„ ๊ฐœ๋ฐœํ•˜๋Š” ๊ฒƒ์ด๋ฉฐ, ํŠนํžˆ `ํŠน์ง• ๊ธฐ๋ฐ˜' ์ด๋ผ๊ณ  ๋ถˆ๋ฆฌ๋Š” ๋‹ค์Œ๊ณผ ๊ฐ™์€ ์ƒํ™ฉ์— ๋Œ€ํ•ด ์ค‘์ ์ ์œผ๋กœ ๋…ผ์˜ํ•œ๋‹ค. ์šฐ์„  ๋ถ„๋ฆฌ ๋Œ€์ƒ์ด ๋˜๋Š” ์Œ์•… ์‹ ํ˜ธ๋Š” ๋‹จ์ฑ„๋„๋กœ ์ œ๊ณต๋œ๋‹ค๊ณ  ๊ฐ€์ •ํ•˜๋ฉฐ, ์ด ๊ฒฝ์šฐ ์‹ ํ˜ธ์˜ ๊ณต๊ฐ„์  ์ •๋ณด๋ฅผ ํ™œ์šฉํ•  ์ˆ˜ ์žˆ๋Š” ๋‹ค์ฑ„๋„ ํ™˜๊ฒฝ์— ๋น„ํ•ด ๋”์šฑ ์–ด๋ ค์šด ํ™˜๊ฒฝ์ด๋ผ๊ณ  ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋˜ํ•œ ๊ธฐ๊ณ„ ํ•™์Šต ๋ฐฉ๋ฒ•์œผ๋กœ ๋ฐ์ดํ„ฐ๋กœ๋ถ€ํ„ฐ ๊ฐ ์Œ์›์˜ ๋ชจ๋ธ์„ ์ถ”์ •ํ•˜๋Š” ๋ฐฉ๋ฒ•์„ ๋ฐฐ์ œํ•˜๋ฉฐ, ๋Œ€์‹  ์ €์ฐจ์›์˜ ํŠน์„ฑ๋“ค๋กœ๋ถ€ํ„ฐ ๋ชจ๋ธ์„ ์œ ๋„ํ•˜์—ฌ ์ด๋ฅผ ๋ชฉํ‘œ ํ•จ์ˆ˜์— ๋ฐ˜์˜ํ•˜๋Š” ๋ฐฉ๋ฒ•์„ ์‹œ๋„ํ•œ๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ, ๊ฐ€์‚ฌ, ์•…๋ณด, ์‚ฌ์šฉ์ž์˜ ์•ˆ๋‚ด ๋“ฑ๊ณผ ๊ฐ™์€ ์™ธ๋ถ€์˜ ์ •๋ณด ์—ญ์‹œ ์ œ๊ณต๋˜์ง€ ์•Š๋Š”๋‹ค๊ณ  ๊ฐ€์ •ํ•œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๋ณด์ปฌ ๋ถ„๋ฆฌ์˜ ๊ฒฝ์šฐ ์•”๋ฌต ์Œ์› ๋ถ„๋ฆฌ ๋ฌธ์ œ์™€๋Š” ๋‹ฌ๋ฆฌ ๋ถ„๋ฆฌํ•˜๊ณ ์ž ํ•˜๋Š” ์Œ์›์ด ๊ฐ๊ฐ ๋ณด์ปฌ๊ณผ ๋ฐ˜์ฃผ์— ํ•ด๋‹นํ•œ๋‹ค๋Š” ์ตœ์†Œํ•œ์˜ ์ •๋ณด๋Š” ์ œ๊ณต๋˜๋ฏ€๋กœ ๊ฐ๊ฐ์˜ ์„ฑ์งˆ๋“ค์— ๋Œ€ํ•œ ๋ถ„์„์€ ๊ฐ€๋Šฅํ•˜๋‹ค. ํฌ๊ฒŒ ์„ธ ์ข…๋ฅ˜์˜ ํŠน์„ฑ์ด ๋ณธ ๋…ผ๋ฌธ์—์„œ ์ค‘์ ์ ์œผ๋กœ ๋…ผ์˜๋œ๋‹ค. ์šฐ์„  ์—ฐ์†์„ฑ์˜ ๊ฒฝ์šฐ ์ฃผํŒŒ์ˆ˜ ๋˜๋Š” ์‹œ๊ฐ„ ์ธก๋ฉด์œผ๋กœ ๊ฐ๊ฐ ๋…ผ์˜๋  ์ˆ˜ ์žˆ๋Š”๋ฐ, ์ฃผํŒŒ์ˆ˜์ถ• ์—ฐ์†์„ฑ์˜ ๊ฒฝ์šฐ ์†Œ๋ฆฌ์˜ ์Œ์ƒ‰์  ํŠน์„ฑ์„, ์‹œ๊ฐ„์ถ• ์—ฐ์†์„ฑ์€ ์†Œ๋ฆฌ๊ฐ€ ์•ˆ์ •์ ์œผ๋กœ ์ง€์†๋˜๋Š” ์ •๋„๋ฅผ ๊ฐ๊ฐ ๋‚˜ํƒ€๋‚ธ๋‹ค๊ณ  ๋ณผ ์ˆ˜ ์žˆ๋‹ค. ๋˜ํ•œ, ์ €ํ–‰๋ ฌ๊ณ„์ˆ˜ ํŠน์„ฑ์€ ์‹ ํ˜ธ์˜ ๊ตฌ์กฐ์  ์„ฑ์งˆ์„ ๋ฐ˜์˜ํ•˜๋ฉฐ ํ•ด๋‹น ์‹ ํ˜ธ๊ฐ€ ๋‚ฎ์€ ํ–‰๋ ฌ๊ณ„์ˆ˜๋ฅผ ๊ฐ€์ง€๋Š” ํ˜•ํƒœ๋กœ ํ‘œํ˜„๋  ์ˆ˜ ์žˆ๋Š”์ง€๋ฅผ ๋‚˜ํƒ€๋‚ด๋ฉฐ, ์„ฑ๊น€ ํŠน์„ฑ์€ ์‹ ํ˜ธ์˜ ๋ถ„ํฌ ํ˜•ํƒœ๊ฐ€ ์–ผ๋งˆ๋‚˜ ์„ฑ๊ธฐ๊ฑฐ๋‚˜ ์กฐ๋ฐ€ํ•œ์ง€๋ฅผ ๋‚˜ํƒ€๋‚ธ๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ํฌ๊ฒŒ ๋‘ ๊ฐ€์ง€์˜ ๋ณด์ปฌ ๋ถ„๋ฆฌ ๋ฐฉ๋ฒ•์— ๋Œ€ํ•ด ๋…ผ์˜ํ•œ๋‹ค. ์ฒซ ๋ฒˆ์งธ ๋ฐฉ๋ฒ•์€ ์—ฐ์†์„ฑ๊ณผ ์„ฑ๊น€ ํŠน์„ฑ์— ๊ธฐ๋ฐ˜์„ ๋‘๊ณ  ํ™”์„ฑ ์•…๊ธฐ-ํƒ€์•…๊ธฐ ๋ถ„๋ฆฌ ๋ฐฉ๋ฒ• (harmonic-percussive sound separation, HPSS) ์„ ํ™•์žฅํ•˜๋Š” ๋ฐฉ๋ฒ•์ด๋‹ค. ๊ธฐ์กด์˜ ๋ฐฉ๋ฒ•์ด ๋‘ ๋ฒˆ์˜ HPSS ๊ณผ์ •์„ ํ†ตํ•ด ๋ณด์ปฌ์„ ๋ถ„๋ฆฌํ•˜๋Š” ๊ฒƒ์— ๋น„ํ•ด ์ œ์•ˆํ•˜๋Š” ๋ฐฉ๋ฒ•์€ ์„ฑ๊ธด ์ž”์—ฌ ์„ฑ๋ถ„์„ ์ถ”๊ฐ€ํ•ด ํ•œ ๋ฒˆ์˜ ๋ณด์ปฌ ๋ถ„๋ฆฌ ๊ณผ์ •๋งŒ์„ ์‚ฌ์šฉํ•œ๋‹ค. ๋…ผ์˜๋˜๋Š” ๋‹ค๋ฅธ ๋ฐฉ๋ฒ•์€ ์ €ํ–‰๋ ฌ๊ณ„์ˆ˜ ํŠน์„ฑ๊ณผ ์„ฑ๊น€ ํŠน์„ฑ์„ ํ™œ์šฉํ•˜๋Š” ๊ฒƒ์œผ๋กœ, ๋ฐ˜์ฃผ๊ฐ€ ์ €ํ–‰๋ ฌ๊ณ„์ˆ˜ ๋ชจ๋ธ๋กœ ํ‘œํ˜„๋  ์ˆ˜ ์žˆ๋Š” ๋ฐ˜๋ฉด ๋ณด์ปฌ์€ ์„ฑ๊ธด ๋ถ„ํฌ๋ฅผ ๊ฐ€์ง„๋‹ค๋Š” ๊ฐ€์ •์— ๊ธฐ๋ฐ˜์„ ๋‘”๋‹ค. ์ด๋Ÿฌํ•œ ์„ฑ๋ถ„๋“ค์„ ๋ถ„๋ฆฌํ•˜๊ธฐ ์œ„ํ•ด ๊ฐ•์ธํ•œ ์ฃผ์„ฑ๋ถ„ ๋ถ„์„ (robust principal component analysis, RPCA) ์„ ์ด์šฉํ•˜๋Š” ๋ฐฉ๋ฒ•์ด ๋Œ€ํ‘œ์ ์ด๋‹ค. ๋ณธ ๋…ผ๋ฌธ์—์„œ๋Š” ๋ณด์ปฌ ๋ถ„๋ฆฌ ์„ฑ๋Šฅ์— ์ดˆ์ ์„ ๋‘๊ณ  RPCA ์•Œ๊ณ ๋ฆฌ์ฆ˜์„ ์ผ๋ฐ˜ํ™”ํ•˜๊ฑฐ๋‚˜ ํ™•์žฅํ•˜๋Š” ๋ฐฉ์‹์— ๋Œ€ํ•ด ๋…ผ์˜ํ•˜๋ฉฐ, ํŠธ๋ ˆ์ด์Šค ๋…ธ๋ฆ„๊ณผ l1 ๋…ธ๋ฆ„์„ ๊ฐ๊ฐ ์ƒคํ… p ๋…ธ๋ฆ„๊ณผ lp ๋…ธ๋ฆ„์œผ๋กœ ๋Œ€์ฒดํ•˜๋Š” ๋ฐฉ๋ฒ•, ์Šค์ผ€์ผ ์••์ถ• ๋ฐฉ๋ฒ•, ์ฃผํŒŒ์ˆ˜ ๋ถ„ํฌ ํŠน์„ฑ์„ ๋ฐ˜์˜ํ•˜๋Š” ๋ฐฉ๋ฒ• ๋“ฑ์„ ํฌํ•จํ•œ๋‹ค. ์ œ์•ˆํ•˜๋Š” ์•Œ๊ณ ๋ฆฌ์ฆ˜๋“ค์€ ๋‹ค์–‘ํ•œ ๋ฐ์ดํ„ฐ์…‹๊ณผ ๋Œ€ํšŒ์—์„œ ํ‰๊ฐ€๋˜์—ˆ์œผ๋ฉฐ ์ตœ์‹ ์˜ ๋ณด์ปฌ ๋ถ„๋ฆฌ ์•Œ๊ณ ๋ฆฌ์ฆ˜๋“ค๋ณด๋‹ค ๋” ์šฐ์ˆ˜ํ•˜๊ฑฐ๋‚˜ ๋น„์Šทํ•œ ๊ฒฐ๊ณผ๋ฅผ ๋ณด์˜€๋‹ค.Singing voice separation (SVS) refers to the task or the method of decomposing music signal into singing voice and its accompanying instruments. It has various uses, from the preprocessing step, to extract the musical features implied in the target source, to applications for itself such as vocal training. This thesis aims to discover the common properties of singing voice and accompaniment, and apply it to advance the state-of-the-art SVS algorithms. In particular, the separation approach as follows, which is named `characteristics-based,' is concentrated in this thesis. First, the music signal is assumed to be provided in monaural, or as a single-channel recording. It is more difficult condition compared to multiple-channel recording since spatial information cannot be applied in the separation procedure. This thesis also focuses on unsupervised approach, that does not use machine learning technique to estimate the source model from the training data. The models are instead derived based on the low-level characteristics and applied to the objective function. Finally, no external information such as lyrics, score, or user guide is provided. Unlike blind source separation problems, however, the classes of the target sources, singing voice and accompaniment, are known in SVS problem, and it allows to estimate those respective properties. Three different characteristics are primarily discussed in this thesis. Continuity, in the spectral or temporal dimension, refers the smoothness of the source in the particular aspect. The spectral continuity is related with the timbre, while the temporal continuity represents the stability of sounds. On the other hand, the low-rankness refers how the signal is well-structured and can be represented as a low-rank data, and the sparsity represents how rarely the sounds in signals occur in time and frequency. This thesis discusses two SVS approaches using above characteristics. First one is based on the continuity and sparsity, which extends the harmonic-percussive sound separation (HPSS). While the conventional algorithm separates singing voice by using a two-stage HPSS, the proposed one has a single stage procedure but with an additional sparse residual term in the objective function. Another SVS approach is based on the low-rankness and sparsity. Assuming that accompaniment can be represented as a low-rank model, whereas singing voice has a sparse distribution, conventional algorithm decomposes the sources by using robust principal component analysis (RPCA). In this thesis, generalization or extension of RPCA especially for SVS is discussed, including the use of Schatten p-/lp-norm, scale compression, and spectral distribution. The presented algorithms are evaluated using various datasets and challenges and achieved the better comparable results compared to the state-of-the-art algorithms.Chapter 1 Introduction 1 1.1 Motivation 4 1.2 Applications 5 1.3 Definitions and keywords 6 1.4 Evaluation criteria 7 1.5 Topics of interest 11 1.6 Outline of the thesis 13 Chapter 2 Background 15 2.1 Spectrogram-domain separation framework 15 2.2 Approaches for singing voice separation 19 2.2.1 Characteristics-based approach 20 2.2.2 Spatial approach 21 2.2.3 Machine learning-based approach 22 2.2.4 informed approach 23 2.3 Datasets and challenges 25 2.3.1 Datasets 25 2.3.2 Challenges 26 Chapter 3 Characteristics of music sources 28 3.1 Introduction 28 3.2 Spectral/temporal continuity 29 3.2.1 Continuity of a spectrogram 29 3.2.2 Continuity of musical sources 30 3.3 Low-rankness 31 3.3.1 Low-rankness of a spectrogram 31 3.3.2 Low-rankness of musical sources 33 3.4 Sparsity 34 3.4.1 Sparsity of a spectrogram 34 3.4.2 Sparsity of musical sources 36 3.5 Experiments 38 3.6 Summary 39 Chapter 4 Singing voice separation using continuity and sparsity 43 4.1 Introduction 43 4.2 SVS using two-stage HPSS 45 4.2.1 Harmonic-percussive sound separation 45 4.2.2 SVS using two-stage HPSS 46 4.3 Proposed algorithm 48 4.4 Experimental evaluation 52 4.4.1 MIR-1k Dataset 52 4.4.2 Beach boys Dataset 55 4.4.3 iKala dataset in MIREX 2014 56 4.5 Conclusion 58 Chapter 5 Singing voice separation using low-rankness and sparsity 61 5.1 Introduction 61 5.2 SVS using robust principal component analysis 63 5.2.1 Robust principal component analysis 63 5.2.2 Optimization for RPCA using augmented Lagrangian multiplier method 63 5.2.3 SVS using RPCA 65 5.3 SVS using generalized RPCA 67 5.3.1 Generalized RPCA using Schatten p- and lp-norm 67 5.3.2 Comparison of pRPCA with robust matrix completion 68 5.3.3 Optimization method of pRPCA 69 5.3.4 Discussion of the normalization factor for ฮป 69 5.3.5 Generalized RPCA using scale compression 71 5.3.6 Experimental results 72 5.4 SVS using RPCA and spectral distribution 73 5.4.1 RPCA with weighted l1-norm 73 5.4.2 Proposed method: SVS using wRPCA 74 5.4.3 Experimental results using DSD100 dataset 78 5.4.4 Comparison with state-of-the-arts in SiSEC 2016 79 5.4.5 Discussion 85 5.5 Summary 86 Chapter 6 Conclusion and Future Work 88 6.1 Conclusion 88 6.2 Contributions 89 6.3 Future work 91 6.3.1 Discovering various characteristics for SVS 91 6.3.2 Expanding to other SVS approaches 92 6.3.3 Applying the characteristics for deep learning models 92 Bibliography 94 ์ดˆ ๋ก 110Docto

    The change of the configuration of hydroxyapatite crystals in enamel by changes of pH and degree of saturation of lactic acid buffer solution

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    Since it was reported that incipient enamel caries can be recovered, previous studies have quantitatively evaluated that enamel artificial caries have been remineralized with fluoride, showing simultaneously the increase of width of surface layer and the decrease of width of the body of legion. There is, however, little report which showed that remineralization could occur without fluoride. In addition, the observations on the change of hydroxyapatite crystals also have been scarcely seen. In this study, enamel caries in intact premolars or molars was induced by using lactic acidulated buffering solutions over 2 days. Then decalcified specimens were remineralized by seven groups of solutions using different degree of saturation (0.212, 0.239, 0.301, 0.355) and different pH (5.0, 5.5, 6.0) over 10 days. A qualitative comparison to changes of hydroxyapatite crystals after fracturing teeth was made under SEM (scanning electron microscopy) and AFM (atomic force microscopy). The results were as follows: 1. The size of hydroxyapatite crystals in demineralized area was smaller than the normal ones. While the space among crystals was expanded, it was observed that crystals are arranged irregularly. 2. In remineralized enamel area, the enlarged crystals with various shape were observed when the crystals were fused and new small crystals in intercrystalline spaces were deposited. 3. Group 3 and 4 with higher degree of saturation at same pH showed the formation of large clusters by aggregation of small crystals from the surface layer to the lesion body than group 1 and 2 with relatively low degree of saturation at same pH did. Especially group 4 showed complete remineralization to the body of lesions. Group 5 and 6 with lower pH at similar degree of saturation showed remineralization to the body of lesions while group 7 didn't show it. Unlike in Group 3 and 4, Group 5 and 6 showed that each particle was densely distributed with clear appearance rather than crystals form clusters together.ope

    INFLUENCE OF POST TYPES AND SIZES ON FRACTURE RESISTANCE IN THE IMMATURE TOOTH MODEL

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    The purpose of this study was to determine the effect of post types and sizes on fracture resistance in immature tooth model with various restorative techniques. Bovine incisors were sectioned 8 mm above and 12 mm below the cementoenamel junction to simulate immature tooth model. To compare various post-and-core restorations, canals were restored with gutta-percha and resin core, or reinforced dentin wall with dual-cured resin composite, followed by placement of D.T. LIGHT-POST, ParaPost XT, and various sizes of EverStick Post individually. All of specimens were stored in the distilled water for 72 hours and underwent 6,000 thermal cycles. After simulation of periodontal ligament structure with polyether impression material, compressive load was applied at 45 degrees to the long axis of the specimen until fracture was occurred. Experimental groups reinforced with post and composite resin were shown significantly higher fracture strength than gutta-percha group without post placement (p < 0.05). Most specimens fractured limited to cervical third of roots. Post types did not influence on fracture resistance and fracture level significantly when cement space was filled with dual-cured resin composite. In addition, no statistically significant differences were seen between customized and standardized glass fiber posts, which cement spaces were filled with resin cement or composite resin individually. Therefore, root reinforcement procedures as above in immature teeth improved fracture resistance regardless of post types and sizesope

    Effect of dentin treatment on proliferation and differentiation of human dental pulp stem cells

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    OBJECTIVES: Sodium hypochlorite (NaOCl) is an excellent bactericidal agent, but it is detrimental to stem cell survival, whereas intracanal medicaments such as calcium hydroxide (Ca[OH]2) promote the survival and proliferation of stem cells. This study evaluated the effect of sequential NaOCl and Ca[OH]2 application on the attachment and differentiation of dental pulp stem cells (DPSCs). MATERIALS AND METHODS: DPSCs were obtained from human third molars. All dentin specimens were treated with 5.25% NaOCl for 30 min. DPSCs were seeded on the dentin specimens and processed with additional 1 mg/mL Ca[OH]2, 17% ethylenediaminetetraacetic acid (EDTA) treatment, file instrumentation, or a combination of these methods. After 7 day of culture, we examined DPSC morphology using scanning electron microscopy and determined the cell survival rate with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. We measured cell adhesion gene expression levels after 4 day of culture and odontogenic differentiation gene expression levels after 4 wk using quantitative real-time polymerase chain reaction. RESULTS: DPSCs did not attach to the dentin in the NaOCl-treated group. The gene expression levels of fibronectin-1 and secreted phosphoprotein-1 gene in both the Ca[OH]2- and the EDTA-treated groups were significantly higher than those in the other groups. All Ca[OH]2-treated groups showed higher expression levels of dentin matrix protein-1 than that of the control. The dentin sialophosphoprotein level was significantly higher in the groups treated with both Ca[OH]2 and EDTA. CONCLUSIONS: The application of Ca[OH]2 and additional treatment such as EDTA or instrumentation promoted the attachment and differentiation of DPSCs after NaOCl treatment.ope

    Inhibition of the Nav1.7 Channel in the Trigeminal Ganglion Relieves Pulpitis Inflammatory Pain

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    Pulpitis causes significant changes in the peripheral nervous system, which induce hyperalgesia. However, the relationship between neuronal activity and Nav1.7 expression following pulpal noxious pain has not yet been investigated in the trigeminal ganglion (TG). The aim of our study was to verify whether experimentally induced pulpitis activates the expression of Nav1.7 peripherally and the neuronal activities of the TGs can be affected by Nav1.7 channel inhibition. Acute pulpitis was induced through allyl isothiocyanate (AITC) application to the rat maxillary molar tooth pulp. Three days after AITC application, abnormal pain behaviors were recorded, and the rats were euthanized to allow for immunohistochemical, optical imaging, and western blot analyses of the Nav1.7 expression in the TG. A significant increase in AITC-induced pain-like behaviors and histological evidence of pulpitis were observed. In addition, histological and western blot data showed that Nav1.7 expressions in the TGs were significantly higher in the AITC group than in the naive and saline group rats. Optical imaging showed that the AITC group showed higher neuronal activity after electrical stimulation of the TGs. Additionally, treatment of ProTxII, selective Nav1.7 blocker, on to the TGs in the AITC group effectively suppressed the hyperpolarized activity after electrical stimulation. These findings indicate that the inhibition of the Nav1.7 channel could modulate nociceptive signal processing in the TG following pulp inflammation.ope
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