• 제목/요약/키워드: phase-contrast

검색결과 840건 처리시간 0.021초

(8-콜레스테릴옥시카보닐)헵타노화 다당류들의 열방성 액정 특성 (Thermotropic Liquid Crystalline Properties of (8-Cholesteryloxycarbonyl)heptanoated Polysaccharides)

  • 정승용;마영대
    • 폴리머
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    • 제30권4호
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    • pp.338-349
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    • 2006
  • 셀룰로오스, 아밀로오스, 키토산, 키틴, 알긴산, 풀루란 또는 아밀로펙틴을 (8-콜레스테릴옥시카보닐)헵타 노일 클로라이드 (CH8C)와 반응시켜 전치환 또는 거의 전치환 (8-콜레스테릴옥시카보닐) 헵타노화 다당류 유도체들을 합성함과 동시에 이들의 열방성 액정의 거동들을 검토하였다. CH8C 의 경우와 같이, 아밀로펙틴 유도체를 제외한 모든 다당류 유도체들은 좌측방향의 나선구조를 지니며 온도상승에 의해 광학피치들 $({\lambda_m}'s)$이 감소하는 단방성 콜레스테릴 상들을 형성하였다. 아밀로펙틴 유도체도 좌측방향의 나선구조를 지닌 단방성 콜레스테릴 상을 형성하나 다른 다당류 유도체들과 달리 콜레스테릴 상의 전 범위에서 반사색깔들을 나타내지 않았다. 이러한 사실은 콜레스테릴 그룹에 의한 나선의 비틀림력은 아밀로펙틴 중의 분기구조에 민감하게 의존함을 시사한다. 다당류 유도체들에서 관찰되는 액정 상의 열적 안정성과 질서도, 동일한 온도에서의 ${\lambda}_m$ 의 크기 그리고 ${\lambda}_m$의 온도 의존성은 콜레스테릴 그룹들을 유연한 스페이서들을 통하여 유연한 흑은 반강직한 골격들에 도입시켜 얻은 고분자들에 대해 보고된 결과와 전혀 다르다. 이들의 결과를 주사슬과 곁사슬의 화학구조 그리고 주사슬의 유연성의 차이와 관련하에서 검토하였다.

콜레스테릴옥시카본화 그리고 (8-콜레스테릴옥시카보닐)헵타노화 이당류들의 열방성 액정 특성 (Thermotropic Liquid Crystalline Properties of Cholesteryloxycarbonated and (8-Cholesteryloxycarbonyl) heptanoated Disaccharides)

  • 정승용;마영대
    • 폴리머
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    • 제31권1호
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    • pp.58-67
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    • 2007
  • 셀로비오스 말토오스 그리고 락토오스를 콜레스테릴 클로로포메이트 또는 (8-콜레스테릴옥시카보닐)헵타노일 클로라이드와 반응시켜 완전치환 콜레스테릴옥시카본화 그리고 (8-콜레스테릴옥시카보닐)헵타노화 이당류 유도체들을 합성함과 동시에 이들의 열방성 특성들을 검토하였다. 모든 콜레스테릴옥시카본화 유도체들(CH1DSs)은 쌍방성 콜레스테릭 상들을 형성하는 반면 모든 (8-콜레스테릴옥시카보닐)헵타노화 유도체들(CH8DSs)은 좌측방향의 나선구조를 지니며 온도상승에 의해 광학피치들(${\lambda}m's$)이 감소하는 단방성 콜레스테릭 상들을 형성하였다. 모든 CH1DSs들은 CH8DSs들과 달리 콜레스테릭 상의 전 범위에서 반사색깔을 나타내지 않았다. 이러한 사실은 콜레스테릴 그룹에 의한 나선의 비틀림력은 콜레스테릴 그룹과 이당류 사슬을 연결하는 스페이서의 길이에 민감하게 의존함을 시사한다. CH8DSs들에서 관찰되는 액정 상의 열적 안정성과 질서도 그리고 ${\lambda}m$의 온도의존성은 콜레스테릴 그룹을 지닌 dimer들과 triplet 그리고 (8-콜레스테릴옥시카보닐)헵타노화 다당류들에 보고된 결과와 전혀 달랐다. 이들의 결과를 반복단위 몰당의 mesogenic 단위들의 수와 주사슬의 유연성의 차이와의 관련하에서 검토하였다.

Moyamoya 질환에서 1차 통과기법을 이용한 자기공명관류영상의 이해 (Understanding on MR Perfusion Imaging Using First Pass Technique in Moyamoya Diseases)

  • 류영환;구은회;정재은;동경래;최성현;이재승
    • 대한디지털의료영상학회논문지
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    • 제12권1호
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    • pp.27-31
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    • 2010
  • The purpose of this study was to investigated the usefulness of MR perfusion image comparing with SPECT image. A total of pediatric 30 patients(average age : 7.8) with Moyamoya disease were performed MR Perfusion with 32 channel body coil at 3T from March 01, 2010 to June 10, 2010. The MRI sequences and parameters were as followed : gradient Echo-planar imaging(EPI), TR/TE : 2000ms/50ms, FA : $90^{\circ}$, FOV : $240{\times}240$, Matrix : $128{\times}128$, Thickness : 5mm, Gap : 1.5mm. Images were obtained contrast agent administrated at a rate of 1mL/sec after scan start 10s with a total of slice 1000 images(50 phase/1 slice). It was measured with visual color image and digitize data using MRDx software(IDL version 6.2) and also, it was compared of measurement with values of normal and abnormal ratio to analyze hemodynamic change, and a comparison between perfusion MR with technique using Warm Color at SPECT examination. On MR perfusion examination, the color images from abnormal region to the red collar with rCBV(relative cerebral blood volume) and rCBF(relative cerebral blood flow) caused by increase cerebral blood flow with brain vascular occlusion in surrounding collateral circulation advancement, the blood speed relatively was depicted slowly with blue in MTT(Mean Transit Time) and TTP(Time to Peak) images. The region which was visible abnormally from MR perfusion examination visually were detected as comparison with the same SPECT examination region, would be able to confirm the identical results in MMD(Moyamoya disease)judgments. Hymo-dynamic change in MR perfusion examination produced by increase and delay cerebral blood flow. This change with digitize data and being color imaging makes enable to distinguish between normal and abnormal area. Relatively, MR perfusion examination compared with SPECT examination could bring an excellent image with spatial resolution without radiation expose.

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담배거세미나방(Spodoplera lilura)에 높은 살충활성을 나타내는 Bacillus thuringiensis subsp. kurstaki KB099 균주의 내독소 단백질 특성 (Characteristics of ${\delta}$-Endotoxin Protein Produced from Bacillus thuringiensis subsp. kurstaki KB099 Isolate Showing High Bioactivity against Spodoptera litura)

  • 정선영;서미자;윤영남;유용만
    • 농약과학회지
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    • 제14권4호
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    • pp.446-455
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    • 2010
  • 주요 농업해충인 담배거세미나방에 대하여 높은 생물활성을 보이는 Bacillus thuringiensis subsp. kurstaki KB099 균주의 내독소단백질의 특성이 검토되었다. 이 균주의 내독소단백질은 효소 처리 없는 SDS-PAGE 결과 HD-l 균주에서는 일부 용해되어 130 kDa과 60 kDa의 두 개의 단백질밴드가 나타났으나 KB099균주에서는 용해되지 않고 130kDa의 밴드만이 관찰되었다. KB099균주의 내독소단백질에 감수성 해충인 담배거세미나방의 중장액으로 소화하였을 때에는 약 60 kDa 단백질밴드가 형성됨을 확인하였다. 또한 두 균주의 각각의 내독소단백질에 감수성해충의 소화액으로 반응시켰을 때 생물활성이 약했던 HD-l균주는 약6시간 만에 주요 밴드가 사라지는데 비해 활성이 강한 KB099균주는 12시간이상 까지도 활성밴드가 유지되다가 24시간 정도에서 밴드가 사라졌다. KB099균주가 생산하는 내독소단백질 유전자의 탐색을 위한 PCR실험에서 Cry1Aa, Cry1Ab, Cry1Ac, Cry1C, Cry1D 그리고 Cry1I 등 6개의 유전자가 존재함을 확인하였다.

서영태(徐靈胎)와 길익동동(吉益東洞)의 학술사상 비교 연구 (II) - 학술 사상이 같고 다른 원인에 대한 분석 - (Comparative Study About Academic Thoughts of Xu Lingtai and Yoshimasu Todo (II) - Analysis of the Cause of Similarities and Differences in their Academic Thoughts -)

  • 윤철호;황황
    • 대한한방내과학회지
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    • 제32권1호
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    • pp.87-99
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    • 2011
  • In the 18th century, Xu Lingtai (徐靈胎) and Yoshimasu Todo (吉益東洞) were medical revolutionaries. They emphasized researches about synthesis of formulae, efficacy of medication and observation and then classification of clinical phenomena, so they assumed a modern scientific character. But, there were clear differences between their academic thoughts. In this paper, we examine the causes of difference in three fields, i.e. traditional culture, viewpoints of talented people and academic personality. The first, difference was due to traditional culture. Chinese medicine has a long history and heavy traditional culture. Yin-Yang (陰陽) theory, Five Phase(五行) theory, Viscera and Bowels (臟腑) theory and Meridian and Collateral (經絡) theory stemmed from everyday practice, and Chinese people learn these theories from experience and observation. From the standpoint of Chinese people, particularly scholarly doctors [儒醫] such as Xu Lingtai, it was easy to debate medical theories. In contrast, Japanese traditional culture didn't have as long a history as China. Thus as a necessity, it was harder to disseminate traditional Chinese medicine theories in Japan. Yoshimasu Todo simplified it by cutting out the superfluous traditional Chinese medicine theory, so at that time it must have been shocking to the Japanese medical world's trends. The second, difference was due to viewpoints of talented experts. From the standpoint of Xu Lingtai, above all, medicine is just a learning, only a kind of technique, even more not a means of living. Xu Lingtai was concerned with the appearance of very talented experts such as 'great man' (偉人), and 'exceptional man' (奇士) who carried out medical research. Instead of cultivating a few talented people, Yoshimasu Todo tried to produce a large number of clinicians quickly who could treat ordinary people. The third was due to personality difference. As Xu Lingtai threw away Confucianism and studied medicine in his youth, although he had a critical attitude, he was always mild-mannered. Yoshimasu Todo always had a clearly critical and rebellious nature. Personality influenced their literary spirit and learning style, so although both advocated reactionism, the academic thought of Xu Lingtai was reformative and mild, while that of Yoshimasu Todo was revolutionary and fierce. Xu Lingtai and Yoshimasu Todo had considerably similar research domains and academic thought, so it is proper for them both to serve as examples for making a comparative study of medical history in China and Japan in 18th century.

감염 근관에서 혐기성 배양법과 간접 면역 형광법 및 DNA 프로브법에 의한 Porphyromonas endodontalis의 검출에 관한 비교 연구 (COMPARATIVE STUDY ON THE DETECTION OF PORPHYROMONAS ENDODONTALIS BY ANAEROBIC CULTURE, IIF AND DNA PROBE METHOD IN INFECTED ROOT CANALS)

  • 김민겸;윤수한;정종평
    • Restorative Dentistry and Endodontics
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    • 제21권1호
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    • pp.1-18
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    • 1996
  • There are many advantages when using IIF and DNA probe methods over anaerobic culture method in that they are time-and effort-saving, more precise and more sensitive. Furthermore, in IIF and DNA probe methods, the detection is possible only with small amount of bacteria, the quantitative analysis is possible, and the cell viability is not necessary. The purpose of this study is to observe the incidence of P.endodontalis by carrying out anaerobic culture, IIF and colony lift using DNA probe method respectively, and to compare these 3 methods in terms of effectiveness and sensitivity in order to identify the most effective detection method. 30 teeth with at least one clinical symptoms, with single canal, and with pulp necrosis were sampled. For sampling bacteria, access cavity was prepared after disinfecting tooth and its surroundings. Then the paper point was inserted up to the periapical area, leave there for a while, and finally it was placed into PRAS Ringer's sol. and PBS sol. In anaerobic culture method, P.endodontalis was identified by biochemical tests after subculturing black and brown colonies which were produced after 7 days of incubation on BAP and Brucella BAP in anaerobic chamber. To identify P.endodontalis in IIF method, species-specific polyclonal rabbit-antisera of P.endodontalis(ATCC 35406) was reacted with sampled PBS sol. dispensed onto glass slide, and then P.endodontalis was examined by phase contrast microscopy after incubating with Goat anti-rabbit lgG conjugated to Fluorescein isothiocyanate. For colony lift using DNA probe method, membranes were laid over colonies on the surface of BAP and were hybridized with cloned DNA probe of P.endodontalis. The existence of P.endodontalis was then identified by the methods of chemiluminescent detection and color metric detection. Black colony was found in 11 teeth out of 30 teeth and P.endodontalis was detected in 6 teeth (20 %) by anaerobic culture method, 16 teeth (53 %) by IIF method, and 7 teeth (23 %) by DNA probe method. IIF method is significantly better in detecting P.endodontalis than DNA probe method and anaerobic culture method. There was no significant differences between DNA probe method and anaerobic culture method. There was significant correlation between the formation of black colony and the existence of P.endodontalis. The probability of detecting P.endodontalis when black colony being present is 2.89 times higher than when not being present. There was significant relationship between the foul odor of clinical symptoms and P.endodontalis. The sensitivity of existing P.endodontalis when foul odor being present was 93.75 %, while the specificity of not existing P.endodontalis when foul odor not being present was 28.57 %. These results suggested that the probes of P.endodontalis will be used to decide the method and prognosis in endodontic treatments.

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느타리 재배에서 버섯파리의 생물학적 방제를 위한 곤충병원성 세균의 분리 및 동정 (Isolation and Identification of Entomopathogenic Bacteria for Biological Control of the Mushroom Fly, Lycoriella mali)

  • 이수희;임은경;최광호;이재필;이현욱;김익수;문병주
    • 한국균학회지
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    • 제30권1호
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    • pp.44-49
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    • 2002
  • 느타리버섯 재배에 있어서 주요해충인 버섯파리 Lycoriella mali의 생물학적 방제를 위하여 전국 느타리버섯 재배지와 버섯파리의 병사충에서 버섯파리 유충에 병원성을 갖는 세균 8균주를 분리하였다. 이 중 Bti-D 및 Bti-U 2균주에 의한 사충율이 각각 82.3%와 87.3%로 가장 높았다. 버섯파리 유충의 발육단계에 따른 살충 효과 검정에서는 두 균주 모두 3령 층에서 높은 살충효과를 보였다. 이들 세균으로 감염된 유충에 나타나는 병징으로서 감염초기에는 중장의 앞부분이 연한 갈색을 띄고, 차츰 중장의 뒷부분까지 진행되어 전 부분이 흑갈색으로 변색되면서 치사되었다. 이들 두 균주를 동정하기 위하여 배양적, 생화학적 및 생리적 특성을 조사하고 Bergey's manual과 Biolog system을 동정에 이용하였으며, 주사전자현미경으로 세포형태를, 위상차현미경으로 내생포자와 내독소를 관찰하여 판정한 결과, 두 균주 모두 Bacillus thuringiensis로 동정되었으며, 편모항원성을 조사한 결과, B. l. subsp. israelensis로 동정되었다.

인삼사포닌의 흰쥐 LDH-A 유전자와 흰쥐 간세포 재생시 DNA 합성률에 미치는 유도효과 (Inductive Effects of Ginseng Saponins on the Rat LDH A-gene and the Synthetic rate of Hepatocyte DNA in Regenerating Rat Liver Cells)

  • 유계진;이광율;이성기
    • Journal of Ginseng Research
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    • 제14권2호
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    • pp.200-206
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    • 1990
  • The effects of ginseng saponins, SRbl and G-Rc on the rat liver LDH A-gene transcriptional activity was investigated during prereplicative phase of rat liver after partial hepatectomy. Changes in LDH A-mRNA levels in regenerating rat liver after intraperitoneal administrations of G-Rbl or 'G-Rc were tested by slot blot hybridization methods. The results showed that G-Rbl (1 mg/100g B.W) and G-Rc (1 mg/100g B.W) caused marked increases of LDH A-mRNA contents by respectively 1.9- and 1.5-fold in rat liver at 5-hours after partial hepatectomy Dose dependent elect of G-Rbl and G-Rc (1-25 mg/ 100g B.W) on the LDH A-mRNA levels on regenerating rat liver were also analyzed. The maximal increases of liver LDH A-mRNA levels were observed with the doses of 1 mg for G-Rbl and 5 mg for G-Rc. However, when the administration doses of G-Rbl and G-Rc were increased to 20 mg, G-Rbl caused a marked decrease of LDH A-mRNA level to 61% of those in sham-operated rat liver. In contrast, G-Rc slightly decreased the liver LDH A-mRNA contents by 30% as compared to those of the maximum value but still maintained 22% higher LDH A-mRNA levels then those of sham-operated rate liver. On the basis of these experimental results, we conclude that ginseng saponin, G-Rbl and G-Rc have stimulatory effect at the lower concentration (1 mg/ 100g B.W) and inhibitory effect at the higher concentration (20 mg/ 100g B.W) on the LDH A-gene transcription during regeneration of rat liver. Additionally we also investigated the stimulatory effects of ginsenosides on the protein and DNA sinthetic activities in hepatocyte primary cell cultures isolated from regenerating rat liver. Both of G-Rc and -Re increased the synthetic rates of hepatocytes proteins and DNA at the administration doses of 50 us and 100 $\mu\textrm{g}$/3 ml/dish respectively representing 1.3-1.6 fold increases. From these results we postulate that G-Rc and -Re may have a mitogen ehincer activity for the hepatocyte proliferation during rat liver regeneration period.

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Quadratic Residue Diffusor Microwave를 이용한 목재의 내부 온도변화에 관한 연구 (Internal Wood Temperature Manipulation Using Quadratic Residue Diffusor Microwaves)

  • 김기호;김경민
    • Current Research on Agriculture and Life Sciences
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    • 제32권1호
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    • pp.1-9
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    • 2014
  • 본 연구에서 사용한 QRD(Quadratic Residue Diffusor) 마이크로파는 일반적인 마이크로파와 달리 파장의 위상차를 변화시켜 균일한 살균을 유도할 수 있어 저전력으로 효과를 높일수 있는 새로운 기술로 알려져 있다. 따라서 친환경적이고 에너지 소비가 적은 QRD 마이크로파를 이용하여 목재를 소독 할 가능성에 대한 기초적인 연구를 수행하였으며 얻은 결과는 아래와 같다. 본 연구에 사용된 QRD microwave의 효율성은 E=5.75e0.32S ($R^2$=0.908)로 나타났으며 초기 수분 함수율은 일정하지 않았고 평균 수분함수율은 30.3%이었다. 자연건조 1주일 후의 수분 함수율은 22.6%로써 평균 약 8% 수분함량이 줄어들었다. 또한 마그네트론의 용량이 3 kW에서 9 kW까지 증가할수록 지수함수적인 관계로 온도 상승시간이 줄어드는 것을 알 수 있었다. 목재 강도 시험 결과에서는 QRD microwave 처리 전후로 휨강도, 압축강도, 할렬의 차이는 없었다. 따라서 QRD microwave 용량을 3, 5, 7, 9 kW로 제작하여 실험한 결과 9 kW가 가장 효율성이 높은 것을 알 수 있었다. 따라서 목재 내부의 선충이나 흰개미 등의 퇴치를 위해서 QRD microwave 용량을 일정부분까지 높여 공급할수록 에너지 효율성에서 유리한 것으로 나타났다.

웹사이트 디자인의 시각적 요소와 유용성이 성과에 미치는 영향에 관한 연구 (A Study on the Effects of Visual Aesthetics and Usability of Web Site Design on their Performance)

  • 김승경;이재관
    • 한국경영과학회지
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    • 제32권2호
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    • pp.17-40
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    • 2007
  • Most research on web site design has focused on technological factors, while visual aesthetic factors have been considered less important. In contrast, this study focuses on visual aesthetic factors in web site design. Findings of this study can be summarized as follows : (1) The result of SPSS-factor analysis shows that there are 3 distinct factors, 'classical aesthetics', 'expressive aesthetics', and 'usability' 'Classical aesthetics' and 'expressive aesthetics' can be described by visual aesthetic design, 'Visual aesthetic design' can be distinguished from 'usability'. This conceptual confusion relating to 'usability' and 'visual aesthetic design' can be clarified by these findings. (2) As a result of multiple regression analyses, 'classical aesthetics', 'expressive aesthetics', and 'usability' have a positive influence on 'interactivity' and 'web site evaluation'. This research clarifies the concepts of 'expectations' of Grier [18] and 'engagement' of Rosen and Purinton [33] as the 'interactivity' between users and web sites. Furthermore, this research suggests a valid model with high $R^2$(interactivity, 48% : web site evaluation, 68%). (3) Empirical tests show that the differences among users in 'entry point' are related to the characteristics of web sites and the personal characteristics of users. The differences among users in terms of 'scanning time' are closely related to the attitudes and evaluation tendencies of users with respect to web sites. These findings could contribute to the 'search phase' of the Faraday model [16], enabling it to be more precise and extensible. The managerial implication of this study is that customers' preferences regarding web site designs are differences, as their preferences are based on their individual characteristics. Therefore, marketing managers should consider promotional tools on web sites that are relevant to the target market. An optimal strategy for web design could be a carefully-selected combination of factors that are relevant to the 'interactivity' and 'evaluation' of web sites. Additionally, if marketing managers want to attract more favorable attitudes and more affirmative evaluations from users, web sites should be designed so that they are understood more quickly by users. finally, this study suggests that 'good design' for web sites depends on understanding how to attain the appropriate balance between 'classical aesthetics' and 'expressive aesthetics', based on the target customer.