• 제목/요약/키워드: ${Al_2}{O_3}$-C

검색결과 2,883건 처리시간 0.037초

Pasteurella multocida에 대(對)한 간이적혈구(簡易赤血球) 응집반응(凝集反應)과 적혈구(赤血球)의 안정화(安定化)에 관(關)한 연구(硏究) (Studies on the Simplified Hemagglutination Reaction to Pasteurella multocida and the Stabilization of Erythrocytes)

  • 이학철;정영건;김교준
    • 대한수의학회지
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    • 제10권1호
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    • pp.11-23
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    • 1970
  • Recently Carter(1952) reported the capsule antigens of Pasteurella multocida could be divided into four serological types A,B,C and D by means of precipitation tests. Subsequently he showed that the most sensitive for identification of these types involved the use of capsule substance adsorbed by erythrocytes in hemagglutination test. It may be somewhat difficult to conduct the hemagglutination test in small laboratory, because relatively large amounts of antisera and erythrocytes of the human O type are required for the test. A simple method for serological typing of P. multocida was the slide agglutination test employed by Little et al. (1943) and Namioka et al. (1962), but this method is still in controversy. The author tried adapting Carter's hemagglutination method to the slide method so called "micromethod technique", and studied on the stabilization of erythrocytes for use of slide hemagglutination to P. multocida although many invesigators reported the stabilization of erythrocytes. The results obtained are summarized as follows: 1. A simplified method (slide method) for capsule typing of the organism was developed by adapting Carter's hemagglutination reaction(tube method). Antibody-containing serum can be diluted serially on Boerner's microtest slide with capillary or serological pipetts with a considerable accuracy. The slide reaction can be carried out with case on the slide by adding $0.05m{\ell}$ of antigen-sensitized erythrocytes suspension diluted to one percent on $0.05m{\ell}$ of serially diluted antibody-containing sera, and the final result can be read after 60 minutes at the room temperature ($15^{\circ}C$). 2. It is difficult to determine superiority of inferiority between the slide method and the tube method on the pattern of the reaction of hemagglutination. 3. The pH range of 6.6 to 8.3 is optimal for the slide hemagglutination reaction. 4. The antigen-sensitization against erythrocytes at $37^{\circ}C$ is optimal for the slide hemagglutination. 5. Both the doses and concentration of antigen do not influence the antigen-adsorbing capacity of erythrocytes. 6. The reduction of antigen-sensitizing hours does not influence the antigen-adsorbing capacity of erythrocytes even 30 minutes. 7. The tannic acid treatment against formalinized and non-formalinized erythrocytes showed no effect on the reaction of hemagglutination. 8. The erythrocytes preserved at $4^{\circ}C$ in the ACD solution do not decrease the reactivity on the reaction of hemagglutination for 60 days, while they begin slight hemolysis 30 days after preserving. 9. The stable preparation of erythrocytes can be obtained by treating the cells at $37^{\circ}C$ for 20 hours with from 4 to 8 percent of formalin in saline or buffer. These cells can be preserved at $4^{\circ}C$ for more than 8 months experimented without hemolysis. With low concentration of formalin, the cells were not sufficiently stabilized resulting in the hemolysis after short period of preservation at $4^{\circ}C$. 10. The erythrocytes treated with 16 percent of formalin remain constantly or increase the reactivity for the reaction of hemagglutination. On the contrary, the cells treated with I to 8 percent of formalin decrease the reactivity. 11. There is no difference between nontreated fresh erythrocytes and the erythrocytes preserved in the ACD solution on the reactivity against the hemagglutination, and the erythrocytes treated with 16 percent of formalin showed the reactivity of higher level than that of the above two kinds of erythrocytes. 12. There is no difference between the saline and the isotonic buffer solution on the reaction of hemagglutination.

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Carbon nanotube field emission display

  • Chil, Won-Bong;Kim, Jong-Min
    • E2M - 전기 전자와 첨단 소재
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    • 제12권7호
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    • pp.7-11
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    • 1999
  • Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).

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화염용융법에 의한 구상 알루미나 제조에 미치는 초기 알루미나 원료의 화학조성과 입도의 영향 (Effects of Chemical Composition and Particle Size of Starting Aluminum Source on the Spheroidization in the Flame Fusion Process)

  • 엄선희;피재환;이종근;황광택;조우석;김경자
    • 한국분말재료학회지
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    • 제16권6호
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    • pp.431-437
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    • 2009
  • Various inorganic fillers improve the thermal conductivity and physical properties of organic products. Alumina has been used a representative filler in the heat radiation sheet for the heat radiation of electric device. The high filling rate of alumina increases the thermal conductivity and properties of products. We successfully developed the spherical alumina by flame fusion process using the oxygen burner with LPG fuel. In the high temperature flame (2500$\sim$3000$^{\circ}C$) of oxygen burner, sprayed powders were melting and then rotated by carrier gas. This surface melting and rotation process made spherical alumina. Especially effects of chemical composition and particle size of stating materials on the melting behavior of starting materials in the flame and spheroidization ratio were investigated. As a result, spheroidization ratio of boehmite and aluminum hydroxide with endothermic reaction of dehydration process was lower than that of the sintered alumina without dehydration reaction.

화학기계적 연마기술 연구개발 동향: 입자 거동과 기판소재를 중심으로 (Chemical Mechanical Polishing: A Selective Review of R&D Trends in Abrasive Particle Behaviors and Wafer Materials)

  • 이현섭;성인하
    • Tribology and Lubricants
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    • 제35권5호
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    • pp.274-285
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    • 2019
  • Chemical mechanical polishing (CMP), which is a material removal process involving chemical surface reactions and mechanical abrasive action, is an essential manufacturing process for obtaining high-quality semiconductor surfaces with ultrahigh precision features. Recent rapid growth in the industries of digital devices and semiconductors has accelerated the demands for processing of various substrate and film materials. In addition, to solve many issues and challenges related to high integration such as micro-defects, non-uniformity, and post-process cleaning, it has become increasingly necessary to approach and understand the processing mechanisms for various substrate materials and abrasive particle behaviors from a tribological point of view. Based on these backgrounds, we review recent CMP R&D trends in this study. We examine experimental and analytical studies with a focus on substrate materials and abrasive particles. For the reduction of micro-scratch generation, understanding the correlation between friction and the generation mechanism by abrasive particle behaviors is critical. Furthermore, the contact stiffness at the wafer-particle (slurry)-pad interface should be carefully considered. Regarding substrate materials, recent research trends and technologies have been introduced that focus on sapphire (${\alpha}$-alumina, $Al_2O_3$), silicon carbide (SiC), and gallium nitride (GaN), which are used for organic light emitting devices. High-speed processing technology that does not generate surface defects should be developed for low-cost production of various substrates. For this purpose, effective methods for reducing and removing surface residues and deformed layers should be explored through tribological approaches. Finally, we present future challenges and issues related to the CMP process from a tribological perspective.

고에너지 밀링분말과 급속소결을 이용한 Ti-Nb-Zr-HA 생체복합재의 기계적 성질 및 생체적합성 (Mechanical Properties and Bio-Compatibility of Ti-Nb-Zr-HA Biomaterial Fabricated by Rapid Sintering Using HEMM Powders)

  • 박상훈;우기도;김상혁;이승민;김지영;고혜림;김상미
    • 한국재료학회지
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    • 제21권7호
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    • pp.384-390
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    • 2011
  • Ti-6Al-4V ELI (Extra Low Interstitial) alloy has been widely used as an alternative to bone due to its excellent biocompatibility. However, it still has many problems, including a high elastic modulus and toxicity. Therefore, nontoxic biomaterials with a low elastic modulus should be developed. However, the fabrication of a uniform coating is challenging. Moreover, the coating layer on Ti and Ti alloy substrates can be peeled off after implantation. To overcome these problems, it is necessary to produce bulk Ti and Ti alloy with hydroxyapatite (HA) composites. In this study, Ti, Nb, and Zr powders, which are biocompatible elements, were milled in a mixing machine (24h) and by planetary mechanical ball milling (1h, 4h, and 6h), respectively. Ti-35%Nb-7%Zr and Ti-35%Nb-7%Zr-10%HA composites were fabricated by spark plasma sintering (SPS) at $1000^{\circ}C$ under 70MPa using mixed and milled powders. The effects of HA addition and milling time on the biocompatibility and physical and mechanical properties of the Ti-35%Nb-7%Zr-(10%HA) alloys have been investigated. $Ti_2O$, CaO, $CaTiO_3$, and $Ti_xP_y$ phases were formed by chemical reaction during sintering. Vickers hardness of the sintered composites increases with increased milling time and by the addition of HA. The biocompatibilty of the HA added Ti-Nb-Zr alloys was improved, but the sintering ability was decreased.

TCO 박막의 결정 구조 및 표면 특성에 따른 OLED 소자의 특성

  • 이봉근;이유림;이규만
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 추계학술대회 논문집
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    • pp.183-183
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    • 2009
  • OLED소자의 양극재료로써 현재는 산화인듐주석(ITO : indium tin oxide) 박막이 널리 이용되고 있다. 그러나 낮은 전기 비저항과 높은 투과도를 갖는 ITO 박막을 얻기 위해서는 $300^{\circ}C$ 이상의 고온에서 성막되어야 하며, 원료 물질인 인듐의 수급량 부족으로 인한 문제점과 독성, 저온증착의 어려움, 스퍼터링 시 음이온 충격에 의한 막 손상으로 저항의 증가의 문제점이 있고, 또한 유기발광소자의 투명전극으로 쓰일 경우에 유기물과의 계면 부적합성, 액정디스플레이의 투명전극으로 사용될 경우에 $400^{\circ}C$정도의 놓은 온도와 수소 플라즈마 분위기에서 장시간 노출 시 열화로 인한 광학적 특성변화가 문제가 된다. 이러한 문제점을 지닌 ITO 박막을 대체할 수 있는 물질로 산화 인듐아연(lZO) 박막이 많은 각광을 받고 있다. IZO(Indium Zinc Oxide) 박막은 저온 ($100^{\circ}C$ 이상)에서 증착이 가능하고 추가적인 열처리 없이도 가시광 영역에서 90% 이상의 광 투과도와 ${\sim}10^{-4}{\Omega}cm$ 이하의 낳은 전기 비저항을 갖는 것으로 알려져 있다. 이러한 IZO박막은 성막 후 고온의 열처리 과정이 필요 없기 때문에 폴리카보네이트와 같은 유기물 기판을 사용하여 제작 가능한 유연한 평판형 표시 소자의 제작에도 적용될 수 있다. IZO(Indium Zinc Oxide) 박막은 상온 공정에서도 우수한 전기적, 광학적, 표면 특성을 나타낼 뿐만 아니라 양극재료로써 높은 일함수를 가지고 있어 고효율의 유기 발광 소자를 구현하는데 유리한 재료라 판단된다. 본 연구에서는 TCO 박막의 면 저항과 표면 거칠기가 OLED 소자의 성능에 미치는 영향을 조사하였다. R.F Magnetron Sputtering을 이용하여 투명 전도막을 성막 형성 하였으며, 기판온도와 증착과정에서 주입되는 산소, 수소의 유랑 변화가 박막의 구조적, 전기적 특성에 어떠한 영향 미치는 것인가를 자세히 규명하였다 ITO 와 IZO박막은 챔버 내 다양한 가스 분위기(Ar, $Ar+O_2$ and $Ar+H_2$) 에서 R.F Magnetron Sputtering 방법으로 증착했다. TCO박막의 구조적인 이해를 돕기 위해서 X-ray diffraction 과 FESEM으로 분석했다. 광학적 투과도와 박막의 두께는 Ultraviolet Spectrophotometer(Varian, cary-500)와 Surface profile mersurement system으로 각각 측정하였다. 면저항, charge carrier농도, 그리고 TCO박막의 이동성과 길은 전기적특성은 Four-point probe와 Hall Effect Measurement(HMS-3000)로 각각 측정한다. TCO 박막의 표면 거칠기에 따른 OLED소자의 성능분석 측면에서는 TCO 박막의 표면 거칠기 조절을 위해 photo lithography 공정을 사용하여 TCO 박막을 에칭 하였다. 미세사이즈 패턴 마스크가 사용되고 에칭의 깊이는 에칭시간에 따라 조절한다. TCO박막의 표면 형태는 FESEM과 AFM으로 관찰하고 그리고 나서 유기메탈과 음극 전극을 연속적으로 TCO 박막위에 증착한다. 투명전극으로 사용되는 IZO기판 상용화를 위해 IZO기판 위에 $\alpha$-NPB, Alq3, LiF, Al순서로 OLED소자를 제작하였다. 전류밀도와 전압 그리고 발광과 OLED소자의 전압과 같은 전기적 특성은 Spectrometer (minolta CS-1000A) 에 의하여 I-V-L분석을 했다.

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RTP 공정을 통한 태양전지용 AZO 박막의 후열처리 특성연구 (A Study on Properites of PV Solar cell AZO thin films post-annealing by RTP technique)

  • 양현훈;김한울;한창준;소순열;박계춘;이진;정해덕;이석호;백수웅;나길주;정운조
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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    • pp.127.1-127.1
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    • 2011
  • In this paper, ZnO:Al thin films with c-axis preferred orientation were prepared on Soda lime glass substrates by RF magnetron sputtering technique. AZO thin film were prepared in order to clarify optimum conditions for growth of the thin film depending upon process, and then by changing a number of deposition conditions and substrate temperature conditions variously, structural and electrical characteristics were measured. For the manufacture of the AZO were vapor-deposited in the named order. It is well-known that post-annealing is an important method to improve crystal quality. For the annealing process, the dislocation nd other defects arise in the material and adsorption/decomposition occurs. The XRD patterns of the AZO films deposited with grey theory prediction design, annealed in a vacuum ambient($2.0{\times}10-3$Torr)at temperatures of 200, 300, 400 and $500^{\circ}C$ for a period of 30min. The diffraction patterns of all the films show the AZO films had a hexagonal wurtzite structure with a preferential orientation along the c-axis perpendicular to the substrate surface. As can be seen, the (002)peak intensities of the AZO films became more intense and sharper when the annealing temperature increased. On the other hand, When the annealing temperature was $500^{\circ}C$ the peak intensity decreased. The surface morphologies and surface toughness of films were examined by atomic force microscopy(AFM, XE-100, PSIA). Electrical resistivity, Gall mobility and carrier concentration were measured by Hall effect measuring system (HL5500PC, Accent optical Technology, USA). The optical absorption spectra of films in the ultraviolet-visibleinfrared( UV-Vis-IR) region were recorder by the UV spectrophotometer(U-3501, Hitachi, Japan). The resistivity, carrier concentration, and Hall mobility of ZnS deposited on glass substrate as a function of post-annealing.

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첨가제(添加劑) 알칼리 법(法)에 의한 일본 잎갈 나무의 펄프화(化) 특성(特性)에 관(關)한 연구(硏究) (Studies on the Pulping Characteristics of Larchwood (Larix leptolepis Gordon) by Alkaline Process with Additives)

  • 임기표;신동소
    • Journal of the Korean Wood Science and Technology
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    • 제7권2호
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    • pp.3-30
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    • 1979
  • 우리나라에서는 일본잎갈나무가 대량(大量) 조림(造林)되어 축적(蓄積)과 생장량(生長量)으로 보아 주요(主要)한 조림(造林) 수종(樹種)이나 각종(各種) 추출물(抽出物)과 활성(活性) phenol 성분(成分)이 많고 심재율(心材率)이 높아 펄프화(化)에서 수율저하(收率低下)와 표백곤란(漂白困難)이 초래(招來)되어 펄프원료(原料)로서의 이용(利用)이 기피(忌避)되고 있다. 따라서 일본잎갈나무의 화학(化學)펄프 원료화(原料化)의 제고(提高)로서 펄프수율(收率) 향상(向上)과 표백성(漂白性) 개선(改善)을 위하여 셀룰로오스보호제를 첨가(添加)한 소다펄프화(化) 특성(特性)을 구명(究明)하였다. 증해(蒸解)는 최고온도(最高溫度) 170$^{\circ}C$까지 90분간(分間) 가열(加熱)하고 90분간(分間) 유지(維持)하는 일정조건(一定條件)으로 황화도(黃化度) 25%, 활성(活性)알칼리 18%의 크라프트법(法)으로 일본잎갈나무의 수령별(樹齡別) 펄프화(化) 특성(特性)을 구명(究明)하고, 18%활성(活性) 알칼리의 소다증해(蒸解)에 첨가제로 2.5% $MgSO_4$, 2.5% $ZnSO_4$, 2.5% $Al_2(SO_4)_3$, 2.5% KI, 2.5% hydroquinone, 2.5% ethylene diamine 또는 0.1~1.0% anthraquinone를 가(加)하여 15년생(年生) 일본잎갈나무의 변재(邊材)와 심재별(心材別) 소다펄프화(化) 특성(特性)을 구명(究明)한 후(後), 0.5% anthraquinone과 18% 활성(活性)알칼리로 증해(蒸解)된 펄프를 3%, 6%, 9% NaOH를 투입(投入)한 30%의 고농도(高農度)펄프를 상압(常壓) 산소표백(酸素漂白)하고, 이산화염소(二酸化鹽素)의 DED로 계속표백(繼續漂白)한 결과(結果) 다음과 같은 결론(結論)을 얻었다. 1. 일본잎갈나무의 수령별(樹齡別) 크라프트펄프는 수령간(樹齡間)에 펄프의 정선수율(精選收率)은 차(差)가 없으나, 수령(樹齡)이 증가함에 따라 펄프의 총수율(總收率)은 감소(減少)하고 비인열도(比引裂度)는 증가하였으며, 목재(木材)의 심재율(心材率), 용적밀도(容積密度) 수(數), 섬유장(纖維長) 및 온수추출물(溫水抽出物)도 증가하는 경향(傾向)을 나타냈다. 2. 일본잎갈나무의 변재(邊材)와 심재별(心材別) 소다증해(蒸解)에 셀룰로오스 보호제로 첨가(添加)된 7종(種)의 첨가제들은 변재(邊材)와 심재(心材)펄프화(化)에 대한 영향(影響)이 대체로 소다법(法)보다 증가되었으나 크라프트법(法)에 미치지 못하고, 크라프트펄프법(法)에 가까운 첨가제는 펄프수율(收率)에서 KI $MgSO_4$, anthraquinone이며, 특(特)히 다른 첨가제의 25분(分) 1이 첨가(添加)된 anthraquinone은 펄프의 정선수율(精選收率)과 KappaNo. 및 비파열도(比破裂度)에서 다른 첨가제보다 효과적이었다. 3. anthraquinone첨가량(添加量)에 따른 변재(邊材)와 심재별(心材別) 소다펄프의 품질(品質)은 변재(邊材)와 심재(心材) 모두 첨가량(添加量)이 많을수록 탈(脫)리그닌도(度)와 펄프수율(收率)이 높으나 활성(活性)알칼리가 낮으면 정선수율(精選收率)도 낮았으며 활성(活性)알칼리 17%의 소다 증해액(蒸解液)에 0.5% anthraquinone을 첨가(添加)한 조건(條件)에서는 크라프트펄프보다 비교적(比較的) 양호(良好)한 펄프가 얻어졌다. 4. 일반화(一般化)된 CEDED표백중(漂白中) 염소화(鹽素化)와 알칼리 추출단계(抽出段階) 대신(代身)에 30%의 고농도(高濃度)펄프에 상압(常壓) 산소표백(酸素漂白)한 ODED표백(漂白)은 산소단계(酸素段階)에서 변재(邊材)와 심재(心材)펄프 모두 NaOH투입량(投入量)이 증가될수록 백색도(白色度)와 비인열도(比引裂度)가 향상(向上)되나 펄프수율(收率)과 Kapa No.는 감소(減少)되었으며, NaOH 투입량(投入量)이 높을수록 펄프품질(品質)은 CEDED 표백(漂白)과 유사(類似)하나 펄프수율(收率)이 떨어졌다. 5. 따라서 본(本) 실험(實驗)에서는 펄프수율(收率) 향상(向上)을 위해서는 원료(原料)에서 심재율(心材率)이 낮은 수령(樹齡)의 경우가 펄프재(材)로 적당(適當)하고, 0.5% anthraquinone을 첨가(添加)한 활성(活性)알카리 18%의 소다증해(蒸解)하는 것이 적당(適當)하며 폐수중(廢水中)의 염소화합물(鹽素化合物)을 감소(減少)시키기 위하여서는 펄프농도(濃度) 30%이상(以上)의 고농도(高濃度)에서 상압(常壓) 산소(酸素)로 표백후(漂白後) 이산화(二酸化) 염소(鹽素)로 DED 표백(漂白)하면 일본잎갈나무의 크라프트법(法)보다 비교적(比較的) 우수(優秀)한 펄프를 얻을 수 있다.

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소아외과의 지수 질환 - 대한소아외과학회 정회원을 대상으로 한 2000년도 전국 조사 - (Index Cases in Pediatric Surgery - a National Survey by the Korean Association of Pediatric Surgeons, 2000 -)

  • 이명덕;김상윤;김우기;김인구;김성철;김신곤;김재억;김재천;김현학;박귀원;박우현;서정민;송영택;오수명;유수영;이두선;이석구;이성철;정상영;정성은;정을삼;정풍만;조마해
    • Advances in pediatric surgery
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    • 제7권2호
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    • pp.147-156
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    • 2001
  • 대한소아외과학회의 연례 행사인 2000년도 주제토의를 소아외과의 지수 질환으로 정하여 1999년 말 현재 3년 이상의 진료 실적을 가진 대한소아외과학회 정회원 36명을 대상으로 미리 작성된 조사서에 의하여 2차례의 수술 증례 수 등록을 시행하였다. 대상 환자는 1997년부터 1999년 말까지 3년간 수술이 시행된 환자로 하였으며, 1차 조사에서 30명이 응답하였고, 미비점 보완을 위한 2차 조사에는 26명이 응답하여 이 성적을 요약하였다. 본 성적을 바탕으로 향 후 대한소아외과학회의 지수 질환 대상 목록표를 작성 제시하였으며, 이를 코드화 하고자 제안하였다.

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Computational Optimization of Bioanalytical Parameters for the Evaluation of the Toxicity of the Phytomarker 1,4 Napthoquinone and its Metabolite 1,2,4-trihydroxynapththalene

  • Gopal, Velmani;AL Rashid, Mohammad Harun;Majumder, Sayani;Maiti, Partha Pratim;Mandal, Subhash C
    • 대한약침학회지
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    • 제18권2호
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    • pp.7-18
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    • 2015
  • Objectives: Lawsone (1,4 naphthoquinone) is a non redox cycling compound that can be catalyzed by DT diaphorase (DTD) into 1,2,4-trihydroxynaphthalene (THN), which can generate reactive oxygen species by auto oxidation. The purpose of this study was to evaluate the toxicity of the phytomarker 1,4 naphthoquinone and its metabolite THN by using the molecular docking program AutoDock 4. Methods: The 3D structure of ligands such as hydrogen peroxide ($H_2O_2$), nitric oxide synthase (NOS), catalase (CAT), glutathione (GSH), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH) and nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) were drawn using hyperchem drawing tools and minimizing the energy of all pdb files with the help of hyperchem by $MM^+$ followed by a semi-empirical (PM3) method. The docking process was studied with ligand molecules to identify suitable dockings at protein binding sites through annealing and genetic simulation algorithms. The program auto dock tools (ADT) was released as an extension suite to the python molecular viewer used to prepare proteins and ligands. Grids centered on active sites were obtained with spacings of $54{\times}55{\times}56$, and a grid spacing of 0.503 was calculated. Comparisons of Global and Local Search Methods in Drug Docking were adopted to determine parameters; a maximum number of 250,000 energy evaluations, a maximum number of generations of 27,000, and mutation and crossover rates of 0.02 and 0.8 were used. The number of docking runs was set to 10. Results: Lawsone and THN can be considered to efficiently bind with NOS, CAT, GSH, GR, G6PDH and NADPH, which has been confirmed through hydrogen bond affinity with the respective amino acids. Conclusion: Naphthoquinone derivatives of lawsone, which can be metabolized into THN by a catalyst DTD, were examined. Lawsone and THN were found to be identically potent molecules for their affinities for selected proteins.