• Title/Summary/Keyword: materials science

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Clinical study on the comparison of gold and zirconia wear in an implant-supported fixed prosthesis (임플란트 지지 고정성 보철물에서 금과 지르코니아의 마모 비교에 대한 임상 연구)

  • Kim, Jee-Hwan;Yang, Seung-Won;Oh, NamSik
    • Journal of Dental Rehabilitation and Applied Science
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    • v.33 no.4
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    • pp.252-259
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    • 2017
  • Purpose: The purpose of this study was to compare and analyze the wear of a prosthesis for 6 months after restoration with implant-supported fixed dental prosthesis made of either zirconia or gold. Materials and Methods: This study was conducted on patients requiring implant-supported fixed dental prostheses on first or second molar from January, 2015 to January, 2016. A total of 47 prostheses and antagonists were examined. Occlusal surface was recorded by impression of each prosthesis and antagonist 1 week and 6 months after prosthesis delivery. The digital files were created by impression scan. Occlusal shapes of 1 week and 6 months were compared and wear of prostheses and antagonists was analyzed. The Mann-Whitney test was used to analyzed the result data underwent normality test using SPSS (Version 23.0, IBM Corporation) Results: Mann-Whitney test revealed that there was no statistically significant difference in the median amount of mean vertical wear for 6 months in zirconia ($50.84{\mu}m$) and gold ($42.84{\mu}m$) prostheses (P > 0.05). When the opposing teeth were natural, the median amount of mean vertical wear of zirconia and gold prostheses was $47.72{\mu}m$ and $41.97{\mu}m$, respectively, and the median amount of mean vertical wear of enamel was $47.26{\mu}m$ and $44.59{\mu}m$, respectively. Statistical analysis showed no significant difference (P > 0.05). Conclusion: Despite the short study period and the small number of experimental groups, zirconia and gold showed no significant difference in wear during the first 6 months. Opposing natural enamel also showed no significant difference in the wear.

Some In-Vitro and In-Vivo Biological Activities of Hot Water Extracts from Fruit Body and Cultured Mycelium of Hericium erinaceum (Hericium erinaceum 균사체와 자실체 열수 추출물의 몇몇 In-Vitro 및 In-Vivo 생물활성)

  • Jung, Jae-Hyun;Lee, Kwang-Ho;Lee, Shin-Young
    • KSBB Journal
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    • v.22 no.1
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    • pp.22-29
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    • 2007
  • The water-soluble materials extracted from fruit bodies and mycelium of H. erinaceum were prepared. In-vitro anticancer activities on cancer cells and In-vivo proliferation effect on mouse peritoneal exudate cell and spleen cell of samples were investigated. Also, nitric oxide (NO) generation of peritoneal exudate cell, IL-2 production capacity of spleen cells and phagocytic activity of peritoneal macrophages were examined. The water extracts of H. erinaceum suppressed the proliferation of cancer cell (HeLa, Raw264.7, Jurkat, KATO3, EL4, LyD9) with concentration-dependent. The water extract from fruit body showed better suppression effect than that from mycelium in most of cancer cells used. The anticancer effect of water extract of fruits body in the range of 0.01 and 10 mg/ml for Raw 264.7 and EL4 cell lines were the same as the Taxol with one thousandth equivalent of fruit body concentration. Water extracts of fruit body and liquid-cultured products of H. erinaceum induced nitric oxide (NO) generation of peritoneal exudate cell and increased NO generation by stimulus of lipopolysaccharide. Water extracts alone did not induce the proliferation and IL-2 production capacity of spleen cells. However, spleen's proliferation and IL-2 production were induced significantly by the addition of lipopolysaccharide and Con A (concanavalin A) or Con A alone, and the effectiveness of mycelium extract with water were more active than those from fruit body.

The Utilization of Corn Stalk, Pine Bark, Pine Leaves, Wheat and Wood Flour as an Extender for Plywood Bonding (옥촉서간(玉蜀黍幹), 송수피(松樹皮), 소맥(小麥), 리기다송엽(松葉), 잣나무엽(葉) 및 목분말(木粉末)을 이용(利用)한 합판(合板)의 접착증량(接着增量)에 관(關)한 연구(硏究))

  • Lee, Phil Woo;Kwon, Jin Heon
    • Journal of Korean Society of Forest Science
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    • v.51 no.1
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    • pp.41-50
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    • 1981
  • The purpose of this study was to evaluate the substitutional possibility of new extender instead of wheat flour, which is extending for plywood adhesives in Korea. As the extending materials corn stalk, pine bark, Pitch and Korean pine leaves, wheat, or wood flour were selected and prepared for the extending powders, dried at $103{\pm}2^{\circ}C$ during 24 hours in the drying oven, followed by being pulverized into 60-100 mesh powder. The extenders were mixed with urea formaldehyde resin in the ratio of 5, 10, 15 or 20%. After plywoods were manufactured by the above extended ratios, dry and wet shear strength and wood failures were analyzed and discussed. The results at the study may be summarized as follows ; 1. In urea formaldehyde resin dry shear strength in plywood extended by wheat flour showed the highest value. 2. Among the extenders in 10 and 20% extension of urea formaldehyde resin wet shear strength of wood flour was higher than that of wheat powder. They had no significant difference statistically. 3. Among the extenders of 5% extension of water soluble phenol formaldehyde resin dry shear strength of plywood extended by Korean pine leaf powder showed the highest value, while wheat powder showed the highest value among 10, 15 and 20% extentions. 4. In water soluble phenol formaldehyde resin the best results of wet shear strength showed in wheat powder. 5. Among the extenders in 15 and 20% extension of water soluble phenol formaldehyde resin, dry and wet shear strength in plywood of corn stalk powder were the highest value next to wheat powder.

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Improvement of Productivity by Forest Tree Breeding Work in Korea (우리나라에서의 임목육종(林木育種)에 의(依)한 생산성(生産性) 증가(增加))

  • Ryu, Jang Bal;Shim, Sang Yung
    • Journal of Korean Society of Forest Science
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    • v.77 no.4
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    • pp.382-388
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    • 1988
  • Improvement of productivity by forest tree breeding work in Korea was estimated for a few important tree species. Progenies of 17 plus trees of red pine (Pines densiflora) outgrew by 57 percentage compared with progenies of unselected trees at age 15. If best three families are selected among the 17, more than double in volume grow-th is expected. The hybrid Pinus rigida ${\times}$ P. taeda showed more than double volume growth compare to P. rigida at a southern plantation at age 15. However, the superiority of the hybrid decreased at northern plantations, mainly because of low coldhardiness of the hybrid. At a northern plantation, the hybrid grew less than the P. rigida on upper hill, while the hybrid grew much better than the P. rigida on flat area. Another hybrid Populus alba ${\times}$ P. glandulosa grew faster than both parents by two to two and half times according to planting sites at age 10. Introduction of Pinus rigida also showed increased volume growth. Volume increase by selection of best five provenances among 45 at age 12 was estimated as 53 percent compare to progenies of plus trees in Korea, Additional 19 percent of volume increase was expected by selection of the best families within the best provenances. Annual production of chestnuts reached about 70,000 M/T by planting resistant clones to chestnut gall wasp (Dryocosmus kuriphilus), which killed almost all susceptible trees. Although polyploid trees and mutants have been produced by colchicine treatments in over 10 tree species, none of them is economically important Remarkable improvement of productivity is expected by biotechnology in future through selection, hybridization, introduction of foreign genes at cell, cell organelle and gene level, and gene transformation. At present, mass propagation of superior planting materials by tissue culture will increase the productivity.

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Effect of Air Pollution on Cherry Tree (Prunus yedoensis Matsumara) Planted on National Roadsides between Cheonju and Kunsan City(II) - Chlorophyll, Magnesium and Sodium Contents in the Leaves - (대기오염(大氣汚染)이 전주(全州)-군산간(群山間) 국도변(國道邊) 왕벚나무에 미치는 영향(影響)(II) - Chlorophyll, Mg 및 Na 함유량(含有量)을 중심으로 -)

  • Hwang, Yu Chul;Kim, Chang Ho;Yim, Kyong Bin
    • Journal of Korean Society of Forest Science
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    • v.81 no.3
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    • pp.224-233
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    • 1992
  • This report succeds the previous paper, the source of materials and statistical designs used were not altered. Under the hypothesis of maleffect of atmospheric pollutions emitted mainly by traffic automobiles on 20-year-old, Prunus yedoensis roadside trees planted along national road between Cheonju abd Kunsan, chlorophyll a and b contents, magnesium and sodium contents of leaves were analysed on September 15. Besides control sites considered to be a pollution free district, 20 polluted road-side sites, 10 on left roadside and 10 on right roadside, oppositely faced in pairs were selected. The leaves collected from 5 trees at each sampling site were bulked to eliminate the individual tree variation. Chlorophyll were extracted by Mackinney and Arnon method. The results obtained are as follows : 1. The planting belt width between road shoulder and paved road face edge for cherry trees, 160~170cm, was considered too narrow for the growing space. 2. On an average, the total chlorophyll content between Cheonju and Iri($8.60{\sim}9.31ml/cm^2$) was lower than that for between Iri and Kunsan($9.24{\sim}10.74ml/cm^2$). 3. The chlorophyll b content showed the difference, higher on right roadside and lower on left side. However this difference could be confirmed by matched pair T-test at 10% level. 4. Without exception, the chlorophyll contents of control sites were higher than those of road-side trees, implying the maleffect of atmospheric pollutants on cherry tree growth. 5. On the contrary, magnesium and sodium contents of the leaves of road-side trees were higher than that of control site trees.

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Preference for Korean Food and Satisfaction of Dormitory Foodservice by Chinese Students Studying at Mokpo National University (중국유학생의 한식 메뉴 선호도 및 기숙사 급식만족도 - 목포대 일부 재학생을 대상으로 -)

  • Jung, Hyun-Young;Jeon, Eun-Raye
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.2
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    • pp.283-289
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    • 2011
  • The preference and satisfaction for Korean food by Chinese students studying at Mokpo National University of Korea were surveyed. The students (n=167) were 53.9% males, 58.1% Korean residents for 6 months and 47.9% in healthy condition. The recognition of Korean food was highly light taste ($3.36{\pm}0.95$) and the preference of Korean food materials was in the order of beef (46.7%), hairtail fish (28.7%), baechu (24.4%), tangerine (49.1%), milk (38.9%) in each food category. Eating habits were feeling of hunger on reason for eating (43.1%), moderate satiety degree for a diet (58.7%), no time for reason to skip diet (48.5%), family for impact factor of eating habits (55.1%) and irregular diet time for the problem of eating habits (40.1%). The recognition of Korean food menu was in the order of baechukimchi, bulgogi, ggakdugi, samgyupsal, ddeokbokki, galbitang, and gomtang; the preference order was bulgogi, doejigalbijjim, soegalbijjim, dakgalbijjim, samgyupsal, galbitang, and dakdoritang. The recognition and preference of Korean food menu were significant in bibimbap, tteokguk, doenjang jjigae, kimchi jjigae, ddeokbokki, japchae, baechukimchi, and ggakdugi (p<0.001), as well as jeonbokjuk, bibimguksu, soegalbijjim, doejigalbijjim, dakgalbijjim, saengseonmaeuntang, gomtamg (p<0.01), hobakjuk, bulgogi, and dakdoritang (p<0.05). The actual dormitory foodservice was twice daily (47.3%), <10~20 min for diet time (65.3%). The reason for using university foodservice was compulsory diet (37.1%) whereas the reason of not using university foodservice was tastelessness (45.5%); kimchi was the most leftover (27.5%). According to foodservice quality attribute, the importance and satisfaction were the highest in hygienic part. Foodservice quality attribute was significant between importance and satisfaction in all items except location of facilities foodservice (p<0.001).

Importance and Performance Analysis of Sanitation Management in Workers at Small and Medium Foodservice Industries Using HACCP Prerequisites (HACCP 선행요건 기준을 활용한 중·소 외식업체 종사자의 위생관리 중요도·수행도 분석)

  • Lee, Hyun-Jun;Hong, Wan-Soo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.10
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    • pp.1497-1507
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    • 2016
  • The purpose of this study was to conduct importance and performance analysis of sanitation management in workers at small and medium foodservice industries using HACCP prerequisites. Questionnaires were distributed to 500 small and medium foodservice industry workers in Seoul Gyeonggi province, and a total of 458 responses were used for analysis. Factors with relatively low comparison degree were as follows. 'Handwashing and clean uniform of employee in the workplace', 'regular checking and managing of trapped vermin and rodents', 'checking stocked raw materials', 'recording and filing the results of improved food safety factors', and 'regular cleaning and sterilizing of monitoring tools' factors must be improved along with their performance levels through sanitation education. According to the IPA results, among the 15 HACCP prerequisite factors with high importance but low performance were '2. Regular checking and managing of trapped vermin and rodents', '4. Handwashing and clean uniform of employee in the workplace', '14. Preventing food cross-contamination'. Furthermore, the small and medium foodservice industry IPA with high importance but low performance were 'Regular checking and managing of trapped vermin and rodents', 'Handwashing and clean uniform of employee in the workplace', and 'Preventing food cross-contamination' for the small foodservice industry, along with 'Vermin and rodents control' and 'Recording and filing the results of improved food safety factors' for the medium foodservice industry. Thus, there is a need for reinforced hygiene education through case studies on actual food service establishments to fulfill sanitation guidelines and set amended guides for much-needed items for small and mid-sized food service.

In Vivo Image and Biodistribution of $^{123}I$-15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP) in Liposarcoma Bearing Nude Mice (지방육종형성 동물모델에서 $^{123}I$-15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP)의 생체분포와 생체영상)

  • Lee, Tae-Sup;Suh, Yong-Sup;Choi, Chang-Woon;Woo, Kwang-Sun;Chung, Wee-Sup;Lim, Soo-Jung;Lim, Sang-Moo;Awh, Ok-Doo
    • The Korean Journal of Nuclear Medicine
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    • v.35 no.5
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    • pp.324-333
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    • 2001
  • Purpose: $^{123}I$-labeled fatty acids have been used in the evaluation of regional myocardial energy metabolism. This study aimed to evaluate the usefulness of $^{123}I$-BMIPP as a liposarcoma-imaging agent. Materials and Methods: We compared in vitro uptakes between liposarcoma(SW872) and glioma(9L) cell lines, and examined biodistribution and in vivo images of $^{123}I$-BMIPP in liposarcoma-bearing nude mice. Cold-BMIPP was labeled with $^{123}I\;using\;Cu^{2+}$ as catalyst. After purification by Sep-pak, radiochemical purity was determined by TLC. We compared cellular uptake between glioma and liposarcoma after incubation of 5, 10, 15, 30, 60, 120, and 180 mins with culture medium containing $^{123}I$-BMIPP. The difference in biodistribution was determined between non-feeding (water only) group for 18 hr and feeding group in normal mice (n=6/group) at 0.5, 2, and 24 hr. In liposarcoma-hearing nude mice model, liposarcoma, SW872, ceil lines were injected subcutaneously into the felt thigh of nude mice. The biodistribution of $^{123}I$-BMIPP was evaluated at 0.5, 2, and 24 hr (n:5 / group) and in vivo Image of $^{123}I$-BMIPP was obtained with gamma camera at 2 and 24 hr in liposarcoma-hearing nude mice. Results: Radiolabeling yield and radiochemical purity were 95% and above 99%, respectively. SW872 cell line showed more increased uptake than 9L with 1.5 times at 180 mins. The clearance of $^{123}I$-BMIPP in various tissues was more delayed in the non-feeding group than in the feeding group, especially at delayed time (24 hr) in normal mice, and the major excreting organ was the gastrointestinal tract. In liposarcoma-bearing nude mice, tumor/blood ratio of $^{123}I$-BMIPP was 0.94, 0.75, and 1.38 and tumor/muscle ratio was 0.66, 1.53, and 1.11 at 0.5, 2, and 24hr, respectively. $^{123}I$-BMIPP was selectively localized in liposarcoma at 24 hr image. Conclusions: These results suggest that $^{123}I$-BMIPP can be used as a liposarcoma-imaging agent.

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Soil Surface Energy Balance and Soil Temperature in Potato Field Mulched with Recycled-Paper and Black Plastic Film (감자밭의 재생종이 및 흑색 플라스틱 필름 멀칭에 따른 지표면 에너지 수지와 토양온도의 변화)

  • 최일선;이변우
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.3
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    • pp.229-235
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    • 2001
  • The thermal and photometric properties of mulching materials modify the radiation and energy balance on the mulched soil surface and thereby change the soil temperature. The soil surface energy balances and soil temperatures under the mulching treatments of non-mulched control, recycled paper (RPM), and black polyethylene film (BPFM) were compared before and after the establishment of potato canopy. On August 30 in 1998 when potato was not emerged yet and solar radiation was 17.9 MJ $m^{-2}$${day}^{-1}$ , the net radiation of the soil surface was estimated as 10.(1, 2. 4, and 1.3 MJ $m^{-2}$${day}^{-1}$ under the control, BPFM, and RPM, respectively. The sensible and latent heat loss from the soil surface was 9.65 MJ $m^{-2}$${day}^{-1}$ in the control, most of the net radiation being lost through evaporation and convection, whereas it amounted only to 1.39 MJ $m^{-2}$${day}^{-1}$ in BPFM and 1.36 MJ $m^{-2}$${day}^{-1}$ in RPM. Therefore, the soil heat fluxes were 0.36 1.02, and 0.06 MJ m$^{-2}$ day$^{-1}$ under the control, BPFM and RPM, respectively. On September 27 when potato canopy was fully developed, the soil surface net radiation in the control was sharply decreased as compared to that of Aug. 30, whereas the net radiation of the mulched soil surfaces showed little changes. The soil heat flux was -0.01, 0.95, and 0.12 MJ $m^{-2}$${day}^{-1}$ at the soil surface under the control, BPFM and RPM, respectively. As the mulching treatments brought about such alteration of energy partitioning into the soil, the highest soil temperature was recorded in BPFM and the lowest in RMP without regard to potato canopy development. However, the soil temperature differences among the treatments become smaller when potato canopy were fully developed.

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SSR Profiling and Its Variation in Soybean Germplasm (콩 유전자원의 SSR Profiling과 변이)

  • Yoon, Mun-Sup;Lee, Jeong-Ran;Baek, Hyung-Jin;Cho, Gyu-Taek;Kim, Chang-Yung;Cho, Yang-Hee;Kim, Tae-San;Cho, Eun-Gi
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.52 no.1
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    • pp.81-88
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    • 2007
  • The evaluation of soybean germplasm has mainly been carried out by morphological characters at Genetic Resources Division, Rural Development Administration (RDA). However, this information has been limited serving a diverse information for user and effectively managing the soybean germplasm. To resolve this problem, soybean collection conserved at RDA gene bank was profiled using nine soybean SSR (Simple Sequence Repeat) markers. Soybean SSR allele was confirmed using genescan and genotyper softwares of automatic sequencer for accurate genotyping of each accession and continuous accumulation of data. SSR profiling of soybean germplasm has been carried out from 2,855 (Satt458) to 4,368 (Satt197) accessions by locus. The number of allele revealed 267 with an average of 29.6 in total accession, and varied from a low of 21 (Satt532 and Satt141) to a high of 58 (Sat_074). Although the number of accessions of wild soybean is less than that of soybean landraces, Korean wild soybean is more variable than other soybean landraces populations in total number of alleles. However, Korean soybean landraces were more variable than Korean wild soybeans in 5 loci. In the allele frequency, wild soybean accessions showed an even distribution in all alleles and higher distribution in low ladder than in high ladder. Also, Korean soybean landraces revealed a high condensed frequency in Satt286 (202 bp, 232 bp), Chinese soybean landraces in Satt197 (171 bp) and Satt458 (173 bp), and Japanese soybean landraces in Sat_074 (244 bp) and Satt458 (170 bp). These SSR profile information will be provided as indications of redundancies or omissions of accessions and can aid in managing soybean collection held at RDA gene bank. The information on diversity analysis could help to enlarge the genetic diversity of materials in breeding program, and could be used to develop a core collection of soybean germplasm.