• 제목/요약/키워드: Microscopic Level

검색결과 385건 처리시간 0.025초

Machined 임플란트와 RBM surface 임플란트의 비교 연구 (A compare research of machined implant and RBM surface implant)

  • 유임수;임성빈;정진형;홍기석
    • Journal of Periodontal and Implant Science
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    • 제38권3호
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    • pp.467-474
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    • 2008
  • Purpose: To evaluate RBM surface implant which has its good character like that good initial stability, early bone formation. Material and Methods: In this study fixures have divided in 2 group: Machined(Group I), RBM(Group II). Total 10 fixtures were implanted on rabbit which sacrificed on week 2 and week 4 for the histological specimens. By these specimens polarized microscopic view, micro CT view, ISQ value were measured, compared and analysed by each group to figure out the evidence that clinical use of RBM implant. Result: ISQ value had no significance differences between 2 groups, However in each group 4, 8 weeks had higher ISQ value than 2 weeks. In polarized microscope, calcification level was following: Group II, Group I. In micro CT, formation of cancellous bone level was following: Group II, Group I. Conclusion: RBM implant was the most excellent on the early bone formation and good initial stability.

천남성 추출물의 Sprague-Dawley 랫드를 이용한 28일 반복 경구투여 DRF독성시험 (A 28 Day Repeated Dose-Oral Toxicity Studies of Arisaema Rhizome Aqueous Extracts in Sprague-Dawley Rats)

  • 김민경;이지선;박영철;최선미;이상훈
    • 한국자원식물학회지
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    • 제28권4호
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    • pp.371-381
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    • 2015
  • The object of this study was to obtain single oral dose toxicity of Arisaema Rhizome (Arisaema amurense f. serratum (Nakai) Kitag) aqueous extracts. Arisaema Rhizome (Chunnamsong in Korean) is one of the most important folk remedy plants used in Asia. In the study, a 28-day rat oral gavage study has been conducted with the extracts from Arisaema Rhizome at dose of 1,250, 2,500 and 5,000 ㎎/㎏/day. The following endpoints were evaluated: clinical observations, body weight, gross and microscopic pathology, clinical chemistry, and hematology. Based on the analysis of these endpoints, it was estimated that NOEL (no observed effect level) for male rats and NOAEL (no observed adverse effect level) for female rats are 5000 ㎎/㎏/day of the water-extracts from Arisaema Rhizome.

Alkaline Sizing of Mechanical Pulp

  • Kim, Bong-Yong;Akira Isogai
    • 펄프종이기술
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    • 제32권5호
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    • pp.1-7
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    • 2000
  • Alkaline Sizing behavior and mechanism of handsheets, which were prepared from thermomechanical pulp (TMP) with alkylketene dimer (AKD), were studied in terms of the conditions of the handsheet-making. AKD content in the TMP handsheets was increased with increasing of AKD addition level and the addition of a polyamideamine-epichlorohydrin resin (PAE) clearly enhanced AKD retention as well as the resultant sizing performance of TMP handsheets. Although drying of the AKD sized TMP webs at $20^{\circ}C$ led to no or quite low sizing level, but TMP handsheets sized with AKD had higher sizing degrees with increasing of the temperature of heat treatment. Scanning electron microscopic observations of the AKD-sized TMP handsheets showed that AKD emulsion particles were present on pulp fiber surfaces independently without coagulation in the TMP handsheets dried at $20^{\circ}C$. Heat treatment of the AKD-sized handsheets resulted in disappearance of the AKD emulsion particles because of their melting and spreading. The addition of calcium carbonate filler to the TMP suspensions did not influence on AKD content in the TMP handsheets. Nevertheless, their sizing degrees clearly increased by the addition of $CaCO_3$filler. Probably, AKD molecules adsorbed on the $CaCO_3$filler particles contribute to the enhancement of sizing performance. Thus, AKD can give sizing features effectively to the TMP handsheets, when they are made under suitable conditions.

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에탄올 유발 위점막 손상에 대한 황련 물 추출물의 방어효과 (Protective Effects of Coptidis Rhizoma on Ethanol-induced Gastric Ulcer in Mice)

  • 변준석
    • 동의생리병리학회지
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    • 제26권1호
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    • pp.67-73
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    • 2012
  • The exposure of gastric mucosa to ethanol produces acute ulcers mediated by inflammatory processes, hemorrhagic erosions and increase of reactive oxygen species. The purpose of this study was to assess the effects of Coptidis Rhizoma(CR) aqueous extracts on hydrochloride (HCl)/ethanol induced gastric ulcer in mice as compared with rebamipide (30 mg/kg) and ranitidine (100 mg/kg). Stomach ulcers were induced by oral ingestion of HCl/ethanol. CR extracts (125, 250 and 500 mg/kg) were orally administered, once a day for 7 continuous days, and 1 hr after last 7th treatment of CR extracts stomach ulcers were induced. Effects of CR extracts on HCl/ethanol-induced gastric ulcer were evaluated based on gross and microscopic observations with anti-oxidant activities. All three different dosages of CR extract significantly decreased HCl/ethanol-induced gastric ulcer compared with the HCl/ethanol control mice. CR extracts also strengthened the antioxidative defense systems - decreased the level of lipid peroxidation but increased the level of catalase, superoxide dismutase and nitrate/nitrite compared with the HCl/ethanol control. The effects of CR extract 500 mg/kg were similar to that of 30 mg/kg rebamipide, and CR extract 250 mg/kg showed similar anti-ulcer effects as compared with ranitidine 100 mg/kg. These results suggest that the gastroprotective effects of CR extracts on mice ulcer models can be attributed to its ameliorating effect on oxidative damages.

차로별 교통류 상호영향에 따른 고속도로 합류부 교통와해 특성 분석에 관한 연구 (Analysis of Breakdown Characteristics by Lane Interaction at Freeway Merging Area with a View of Time and Space)

  • 김상구;김영춘
    • 대한교통학회지
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    • 제25권2호
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    • pp.73-81
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    • 2007
  • 본 연구는 개별차량에 대한 미시적 분석이 가능한 고속도로의 실제 항공사진자료를 분석함으로써 고속도로-연결로 접속부를 포함한 합류구간의 교통류 특성을 차로별로 미시적으로 분석하여 기존 연구결과에서 찾아내지 못한 차로별 상호영향에 대한 기초연구를 수행함을 목적으로 한다. 본 연구에서는 고속도로-연결로 접속부에서 수집한 항공사진 원시 자료를 Matlab 프로그램을 사용하여 차로별 30초 단위의 교통량, 속도, 밀도자료를 생성하였고, 또한, 미시적 분석을 위하여 개별차량 차두시간(headway) 데이터를 차로별로 생성하였다. 연구수행 내용으로는 개별차로에 따른 속도, 점유율, 교통량, 차두시간 변화추이를 각각의 차로별로 비교하여 차로특성을 분석하였고 연결로 진입교통량으로 인한 본선 교통류의 정체과정을 분석하였고, 시간과 거리에 따른 시공간도를 작성하여 합류구간 교통류 특성에 대해 해석해보았다. 전체구간을 3개의 지점(합류전, 합류, 합류후)으로 구분하여 차로별 교통류 전이과정을 분석하였으며, 합류구간을 50ft지점으로 세분화하여 교통와해(breakdown)가 발생되는 정확한 위치를 찾아내어 교통류 전파과정을 면밀히 관찰하였다. 본 연구는 혼잡교통류 상태의 연결로 교통류와 본선 교통류간의 관계에 대한 미시적 분석을 수행하여 교통와해현상에 대한 정밀한 분석과 합류구간의 교통와해에 대한 다양한 분석방법을 제시하였으며, 이는 교통와해의 동적변화로 인한 고속도로 동적용량 결정을 할 수 있는 기초이론을 제공한다는 데에 의의가 있다.

Isolation and Identification of Superior Bifidobacterium strains from Korean Feces

  • 김지연;이윤종;최수임;허태련
    • 한국생물공학회:학술대회논문집
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    • 한국생물공학회 2001년도 추계학술발표대회
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    • pp.422-425
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    • 2001
  • For isolating and identifying Bifidobacterium spp. originating from Korea, feces were sampled from healthy Korean infants nursery school and postpartum care center. Through the use of gram staining and microscopic examination for cell morphology, 87 bacterial strains presumed to be the Bifidobacterium strains were isolated from 59 Koreans. To identify the Bifidobacterium strains at the genus level, these bacteria were then analyzed using the TLC method. As a result, 29 of the isolated strains were confirmed as members of the genus Bifidobacterium. 29 Bifidobacterium strains were tested acid, bile salts and oxygen tolerance and investigated antioxidative effect specially. And determined the superiority of 5 strains out of 29 Bifidobacterium strains. Finally, the selected bifidobacterium was identified with using designed 16S-ITS rDNA primer.

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단위 셀을 이용한 평직의 투과율 계수 예측 (Prediction of Permeability through Plain Woven Fabric by Using Unit Cell)

  • Song, Young-Seok;Youn, Jae-Ryoun
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2002년도 봄 학술발표회 논문집
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    • pp.384-387
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    • 2002
  • In the resin transfer molding, there are many advantages such as high volume, high performance, and low cost, The permeability is essential in the design and operation of the process, Traditionally, the determination of permeability can be divided as three methods, which are experimental measurement, analytical, and numerical prediction using the Darcy's law. In this study, the permeability in the microscopic level is first computed on the square-packing and hexagonal packing structures of the filaments inside the yarn by using CVFEM. (omitted)

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미세 골조직의 공극탄성계수 측정을 위한 예비 연구 (A Pilot study of poroelastic modulus measurement in micro-bone tissue)

  • 박영환;홍정화
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 추계학술대회 논문집
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    • pp.1038-1041
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    • 2004
  • In this study, developed a micro-level experimental setup to measure pore pressure and poroelastic modulus in various strain and strain rate about a stress in micro-structure of bone tissue. It is essential device in the development of the model to analysis the interstitial bone fluid flow of the lacuno-canalicular system to be known that would effect on the bone remodeling. The constitution of the experimental setup is as follows, microscopic image processing system; actuator control unit; load measurement system. A pilot study was used an artificial chemical wood to have similar poroelastic property of bone matrix and conducted to validate the suitability of the measurement system.

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전위 및 공공을 고려한 고변형률 변형에 대한 재료 시뮬레이션 (A Material Simulation of High-Strain-Rate Deformation with Dislocations and Vacancies)

  • 최덕기;유한규
    • 대한기계학회논문집A
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    • 제28권9호
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    • pp.1306-1313
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    • 2004
  • This paper addresses a theoretical approach to calculate the amount of the stored energy during high strain-rate deformations using atomistic level simulation. The dynamic behavior of materials at high strain-rate deformation are of great interest. At high strain-rates deformations, materials generate heat due to plastic work and the temperature rise can be significant, affecting various properties of the material. It is well known that a small percent of the energy input is stored in the material, and most of input energy is converted into heat. However, microscopic analysis has not been completed without construction of a material model, which can simulate the movement of dislocations and vacancies. A major cause of the temperature rise within materials is traditionally credited to dislocations, vacancies and other defects. In this study, an atomistic material model for FCC such as copper is used to calculate the stored energy.

Sacral Perineural Cyst Accompanying Disc Herniation

  • Ju, Chang-Il;Shin, Ho;Kim, Seok-Won;Kim, Hyeun-Sung
    • Journal of Korean Neurosurgical Society
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    • 제45권3호
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    • pp.185-187
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    • 2009
  • Although most of sacral perineural cysts are asymptomatic, some may produce symptoms. Specific radicular pain may be due to distortion, compression, or stretching of nerve root by a space occupying cyst. We report a rare case of S1 radiculopathy caused by sacral perineural cyst accompanying disc herniation. The patient underwent a microscopic discectomy at L5-S1 level. However, the patient's symptoms did not improved. The hypesthesia persisted, as did the right leg pain. Cyst-subarachnoid shunt was set to decompress nerve root and to equalize the cerebrospinal fluid pressure between the cephalad thecal sac and cyst. Immediately after surgery, the patient had no leg pain. After 6 months, the patient still remained free of leg pain.