• 제목/요약/키워드: fibrillation

검색결과 465건 처리시간 0.025초

내부소섬유화가 종이 물성에 미치는 영향 (Effect of Internal Fibrillation on the Paper Properties)

  • 원종명
    • 펄프종이기술
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    • 제35권1호
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    • pp.1-6
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    • 2003
  • This study was carried out to investigate the effect of internal fibrillation on the pulp and paper properties. The internal fibrillation was introduced into the SwBKP and recycled SwBKP by the mechanical treatment with Hobart mixer. WRV and physical properties of SwBKP were improved by the internal fibrillation. However the mechanical treatment of recycled SwBKP resulted in the decrease of strength properties of paper except for the tear index, although it was observed that WRV was somewhat increased by the mechanical treatment. The decrease of strength properties of recycled SwBKP might be caused by the hornification of fiber and the decrease of fiber strength.

Use of Modern Microscopes in Analysing Fiber and Paper Properties (II)-New Aspect in Fibrillation of Pulp Fibers during Refining-

  • Kim, Chul-Hwan;Keigh R. Wadhams
    • 펄프종이기술
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    • 제31권3호
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    • pp.60-67
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    • 1999
  • The CLSM and the image analysis technique enhanced observation of fiber wall fibrillation occurred in both the outer and the fiber wall surfaces during refining by non-destructive techniques. In the early stages of refining, it was well observed that a partial separation between the S1 and S2 layer in the secondary wall was made generating a space in the wet fiber walls . With further refining, it was clearly shown that the shear forces imparted by the refiner bar surfaces caused the S1 layer to become totally separated from the S2 layer as well as creating microfibrils. Furthermore, the fibrillation in the inner fiber wall surfaces could be due to the normal force (Fn) by refiner bars, friction force between a fiber and refiner bars (Fs) and inner friction force between fiber walls(fs). It was confirmed that the concept of fibrillation should be extended to fibrillation in the inner fiber wall surfaces as well as internal and external fribrillation.

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Monitoring fibrillation of the pathogenic huntingtin protein using NMR

  • Seo, Min-Duk
    • 한국자기공명학회논문지
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    • 제24권2호
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    • pp.43-46
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    • 2020
  • Huntington's disease (HD) is an inherited neurodegenerative disease caused by abnormal polyglutamine (polyQ) expansion in the huntingtin protein (Htt). There is no cure for HD so far. Although exact molecular mechanism of HD pathogenesis is still elusive, fibril formation of the expanded Htt is linked to the toxicity. In this study, we prepared the expanded Htt containing 46 glutamines, and induced the fibrillation by proteolytic cleavage. Fibrillation of the pathogenic Htt has been monitored by time course NMR experiment. The NMR-based monitoring method could be widely used to screen the candidates to inhibit the fibrillation of the pathogenic Htt.

웨이브렛과 신경망 기반의 심실 세동 검출 알고리즘에 관한 연구 (A Study on the Detection of the Ventricular Fibrillation based on Wavelet Transform and Artificial Neural Network)

  • 송미혜;박호동;이경중;박광리
    • 대한전기학회논문지:시스템및제어부문D
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    • 제53권11호
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    • pp.780-785
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    • 2004
  • In this paper, we proposed a ventricular fibrillation detection algorithm based on wavelet transform and artificial neural network. we selected RR intervals, the 6th and 7th wavelet coefficients(D6, D7) as features for classifying ventricular fibrillation. To evaluate the performance of the proposed algorithm, we compared the result of the proposed algorithm with that of fuzzy inference and fuzzy-neural network. MIT-BIH Arrhythmia database, Creighton University Ventricular Tachyarrhythmia database and MIH-BIH Malignant Ventricular Arrhythmia database were used as test and learning data. Among the algorithms, the proposed algorithm showed that the classification rate of normal and abnormal beat was sensitivity(%) of 96.10 and predictive positive value(%) of 99.07, and that of ventricular fibrillation was sensitivity(%) of 99.45. Finally. the proposed algorithm showed good performance compared to two other methods.

Intracardiac Signal의 스펙트럼 분석을 통한 Atrium Tachycardia 및 Fibrillation 검출 (Detection of atrial tachycardia and fibrillation using spectrum analysis of intracardiac signal)

  • 신항식;이충근;김진권;주영민;이명호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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    • pp.29-31
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    • 2005
  • Detection methods for atrial tachycardia and fibrillation on the time axis have the advantages of light operational load and are easy to apply to various applications. Despite these advantages, arrhythmia detection algorithm on the time axis cannot stand much noise such as motion artifacts, moreover the peak detection algorithm has high complexity. In this paper, we use a spectrum analysis method for the detection of atrial tachycardia and fibrillation. By applying spectrum analysis and digital filtering on obtained electrogram signals, we can diagnose heart arrhythmia without using peak detection algorithm.

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Intracardiac Signal의 스펙트럼 분석을 통한 Atrial Tachycardia 및 Atrial Fibrillation 검출 (Detection of Atrial Tachycardia and Atrial Fibrillation Using Spectrum Analysis of Intracardiac Signal)

  • 이충근;정보영;이명호;신항식
    • 대한전기학회논문지:시스템및제어부문D
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    • 제55권3호
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    • pp.142-145
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    • 2006
  • Detection methods for atrial tachycardia and atrial fibrillation on the time axis have the advantages of light operational load and are easy to apply to various applications. Despite these advantages, arrhythmia detection algorithm on the time axis cannot stand much noise such as motion artifacts, moreover the peak detection algorithm has high complexity. In this paper, we use a spectrum analysis method for the detection of atrial tachycardia and atrial fibrillation. By applying spectrum analysis and digital filtering on obtained electrogram signals, we can diagnose heart arrhythmia without using peak detection algorithm.

Mechanism of amyloidogenesis: nucleation-dependent fibrillation versus double-concerted fibrillation

  • Bhak, Ghi-Bom;Choe, Young-Jun;Paik, Seung-R.
    • BMB Reports
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    • 제42권9호
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    • pp.541-551
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    • 2009
  • Amyloidogenesis defines a condition in which a soluble and innocuous protein turns to insoluble protein aggregates known as amyloid fibrils. This protein suprastructure derived via chemically specific molecular self-assembly process has been commonly observed in various neurodegenerative disorders such as Alzheimer's, Parkinson's, and Prion diseases. Although the major culprit for the cellular degeneration in the diseases remains unsettled, amyloidogenesis is considered to be etiologically involved. Recent recognition of fibrillar polymorphism observed mostly from in vitro amyloidogeneses may indicate that multiple mechanisms for the amyloid fibril formation would be operated. Nucleation-dependent fibrillation is the prevalent model for assessing the self-assembly process. Following thermodynamically unfavorable seed formation, monomeric polypeptides bind to the seeds by exerting structural adjustments to the template, which leads to accelerated amyloid fibril formation. In this review, we propose another in vitro model of amyloidogenesis named double-concerted fibrillation. Here, two consecutive assembly processes of monomers and subsequent oligomeric species are responsible for the amyloid fibril formation of $\alpha$-synuclein, a pathological component of Parkinson's disease, following structural rearrangement within the oligomers which then act as a growing unit for the fibrillation.

공초점반사현미경법을 이용한 섬유의 외부소섬유화 분석 (Analysis of External Fibrillation of Fiber by Confocal Reflection Microscopy)

  • 권오경
    • 펄프종이기술
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    • 제46권2호
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    • pp.35-45
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    • 2014
  • Confocal Reflection Microscopy (CRM) was applied to investigate external fibrillation of different types of fibers such as Kajaani reference fiber, Whatman filter fiber, thermomechanical pulp (TMP), and recycled TMP fiber. It was confirmed that the CRM images are created from surface structures of the fiber cell wall. Confocal Laser Scanning Microscopy (CLSM) captured overall shape of the fiber, but minute details of the surface of the fiber were missed. CRM captured the minute details of the fiber surface. From the CRM and CLSM images, it was observed that the CRM images mainly appeared on the fiber surfaces. External fibrillation of the fiber occurs at the fiber surface, not inside the cell wall. Thus, it was concluded that investigation on the external fibrillation of the fiber was possible by utilizing CRM images. A direct qualtitative and quantitative method for analysis of external fibrillation of fiber was demonstrated by utilizing surface area to volume ratio, volume fraction, and roughness calculated from 3-dimensional images reconstructed from stacks of CRM images from the different fibers.

심방세동 대상자의 우울, 주관적 건강지각 관련요인 (Correlates of Depression and Perceived Health Status in Patients with Atrial Fibrillation)

  • 강윤희
    • 성인간호학회지
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    • 제21권1호
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    • pp.86-94
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    • 2009
  • Purpose: The purpose of this study was to determine correlates of depression and perceived health status in patients with atrial fibrillation. Methods: The study utilized a descriptive correlational survey design. A convenience sample of 115 subjects were recruited from 3 tertiary medical centers. The data were analyzed by descriptive statistics, hierarchical multiple regression. Results: 1) Study subjects perceived the low frequency of symptoms, relatively high social support, low depression, moderately low physical health, and mental health. 2) The 38% of variance in depression was significantly explained by symptom(${\beta}$ = .49), social support(${\beta}$ = -.21), and education(${\beta}$ = -.17). 3) The 40% of variance in physical health was significantly explained by symptom(${\beta}$ = -.55), social support(${\beta}$ = .16), and education(${\beta}$ = .20). 4) the 12% of variance in mental health was significantly explained by symptom(${\beta}$ = -.26), and social support(${\beta}$ = .24). Conclusion: Most health care providers assume atrial fibrillation patients have very few symptoms. However, symptom related to atrial fibrillation was found to be the most important factors in explaining depression and perceived health status. Additionally, higher social support had great influences on the lower depression and higher perceived health status. Based on the findings of this study, directions for nursing practice and further nursing research for patients with atrial fibrillation are suggested.

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