• Title, Summary, Keyword: Reversibility

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The Complementary Role of FEV6 in Bronchodilator Reversibility Test for the Old Age (노인환자의 기도가역성 검사에서 FEV6의 보완적 지표로서의 역할)

  • Kim, Sae Hee;Lee, Yang Deok;Lee, Jung Yun;Cho, Yong Seon;Na, Dong Jip;Han, Min Soo
    • Tuberculosis and Respiratory Diseases
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    • v.61 no.3
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    • pp.227-232
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    • 2006
  • Background: In the measurement of bronchodilator reversibility, the forced expiratory volume in one second($FEV_{1}$) and the forced vital capacity(FVC) are commonly used parameters and recommended criteria for the reversibility requiring an increase of more than 200ml and 12% above the baseline, respectively. However, aged patients do not often meet the criteria of an increase in volume(>200ml) even though the medical history of that patient is adequate for asthma. This study investigated the role of the forced expiratory volume in six seconds($FEV_{6}$) in the bronchodilator reversibility test in elderly patients. Methods: A total of 236 patients more than 65 years of age with a $FEV_{1}$/FVC ratio<80% were enrolled in this study. The bronchodilator revesibility tests were examined. With the setting $FEV_{1}$ as the baseline, the patients were divided into three groups; Group I : $$FEV_{1}{\geq_-}80%$$ of the predicted value, Group II : 60%<$FEV_{1}$<80% of the predicted value, Group III : $$FEV_{1}{\leq_-}60%$$ of the predicted value. Results: Positive reversibility in the $FEV_{1}$, $FEV_{6}$, and FVC was in 33(14.0%), 49(20.8%) and 55(23.3%). However, Group III presented with reversibility in the $FEV_{1}$, $FEV_{6}$, and FVC in 15(22.4%), 30(44.8%) and 32(47.8%) respectively. Conclusions: The $FEV_{6}$ might be used as a complementary parameter in bronchodilatror reversibility in elderly patients. However, more study will be needed to determine the usefulness of $FEV_{6}$ in bronchodilator reversibility test.

Role of Bronchodilator Reversibility Testing in Differentiating Asthma From COPD (만성폐쇄성폐질환과 천식을 감별 진단하는데 기관지확장제 가역성 검사의 역할)

  • Oh, Yeon-Mok;Lim, Chae Man;Shim, Tae Sun;Koh, Younsuck;Kim, Woo Sung;Kim, Dong-Soon;Kim, Won Dong;Kim, Se Kyu;Yoo, Jee Hong;Lee, Sang Do
    • Tuberculosis and Respiratory Diseases
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    • v.57 no.5
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    • pp.419-424
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    • 2004
  • Background : Although bronchodilator reversibility testing is widely performed to diagnose asthma or COPD, there is debate upon its usefulness and methods to differentiate asthma from COPD. The purpose of this study is to elucidate the role of bronchodilator reversibility testing in differentiating asthma from COPD and to confirm which method is better at evaluating bronchodilator reversibility. Methods : 26 asthma patients and 31 COPD patients were reviewed retrospectively. Spirometry was performed before and after bronchodilator inhalation to get $FEV_1$, FVC. To evaluate bronchodilator reversibility, the increase in $FEV_1$ or FVC was expressed as three methods, 'percentage of the baseline value', 'percentage of the predicted value', or 'absolute value'. Area under the ROC curve was measured to compare the three methods. In addition, the criteria of American Thoracic Society (ATS) for bronchodilator reversibility were compared to those of European Respiratory Society (ERS). Results : 1. In differentiating asthma from COPD, 'percentage of the predicted value', or 'absolute value' method was useful but 'percentage of the baseline value' was not. However, the ability to differentiate was weak because areas under the ROC curves by all methods were less than 0.75. 2. The criteria of ERS were superior to those of ATS for bronchodilator reversibility to differentiate asthma from COPD because likelihood ratio (LR) of a positive test by ERS criteria was greater than ATS criteria and because LR of a negative test by ERS criteria was less than ATS criteria. Conclusion : In differentiating asthma from COPD, bronchodilator reversibility testing has a weak role and should be considered as an adjunctive test.

A Reversible Watermarking Algorithm Utilizing Virtually Extended Codebook in the Index Image (컬러색인영상에서 가상확장 코드북을 이용한 무손실 워터마킹)

  • Kim Hyoung-Joong;Yang Jae-Su;Choi Yong-Soo
    • 한국정보통신설비학회:학술대회논문집
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    • pp.274-279
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    • 2006
  • 대부분의 컬러 영상들은 코드북의 일부분만으로 표현할 수 있는 영상의 영역이 상당히 크므로 이러한 특징을 이용하는 효율적인 Reversible 워터마킹 기법을 제안한다. 팔레트(컬러맵) 영상에서의 워터마킹 기술에 대한 연구는 많이 있지만 Reversibility에 대한 관심은 상대적으로 낮았다. 제안하는 기법은 가상적으로 확장한 코드북에 의한 압축 영역에서 동작한다. 확장된 코드북은 높은 Payload 용량을 가진다. Reversibility를 구현하면서 왜곡(Distortion)과 삽입용량(Embedding capacity)사이의 절충점을 실험을 통해 보인다.

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Some Basic and Asymptotic Properies in INMA(q) Processes

  • Park, You-Sang;Kim, Myung-Jin
    • Journal of the Korean Statistical Society
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    • v.26 no.2
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    • pp.155-170
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    • 1997
  • We propose an integer-valued MA(q) process with Poisson disturbance. Its various properties are discussed such as the joint distribution, time reversibility and regression. We derive the asymptotic distribution of autocovariance function and estimators of the parameters in the suggested model. We also consider the relationship between INMA(q) and M/D/.infty. processes.

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A Study on the Information Reversibility of Quantum Logic Circuits (양자 논리회로의 정보 가역성에 대한 고찰)

  • Park, Dong-Young
    • The Journal of the Korea institute of electronic communication sciences
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    • v.12 no.1
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    • pp.189-194
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    • 2017
  • The reversibility of a quantum logic circuit can be realized when two reversible conditions of information reversible and energy reversible circuits are satisfied. In this paper, we have modeled the computation cycle required to recover the information reversibility from the multivalued quantum logic to the original state. For modeling, we used a function embedding method that uses a unitary switch as an arithmetic exponentiation switch. In the quantum logic circuit, if the adjoint gate pair is symmetric, the unitary switch function shows the balance function characteristic, and it takes 1 cycle operation to recover the original information reversibility. Conversely, if it is an asymmetric structure, it takes two cycle operations by the constant function. In this paper, we show that the problem of 2-cycle restoration according to the asymmetric structure when the hybrid MCT gate is realized with the ternary M-S gate can be solved by equivalent conversion of the asymmetric gate to the gate of the symmetric structure.

A quasistatic crack propagation model allowing for cohesive forces and crack reversibility

  • Philip, Peter
    • Interaction and multiscale mechanics
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    • v.2 no.1
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    • pp.31-44
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    • 2009
  • While the classical theory of Griffith is the foundation of modern understanding of brittle fracture, it has a number of significant shortcomings: Griffith theory does not predict crack initiation and path and it suffers from the presence of unphysical stress singularities. In 1998, Francfort and Marigo presented an energy functional minimization method, where the crack (or its absence) as well as its path are part of the problem's solution. The energy functionals act on spaces of functions of bounded variations, where the cracks are related to the discontinuity sets of such functions. The new model presented here uses modified energy functionals to account for molecular interactions in the vicinity of crack tips, resulting in Barenblatt cohesive forces, such that the model becomes free of stress singularities. This is done in a physically consistent way using recently published concepts of Sinclair. Here, for the consistency of the model, it becomes necessary to allow for crack reversibility and to consider local minimizers of the energy functionals. The latter is achieved by introducing different time scales. The model is solved in its global as well as in its local version for a simple one-dimensional example, showing that local minimization is necessary to yield a physically reasonable result.

A Quantitative Method for the Assessment of Myocardial Function using the Polar Analysis of Tc-99m-MIBI Myocardial SPECT (Tc-99m-MIBI 심근 SPECT 극성지도 분석에 의한 심근 기능의 정량적 평가)

  • Kwark, Cheol-Eun;Lee, Dong-Soo;Yeo, Jung-Suk;Lee, Kyung-Han;Chung, June-Key;Lee, Myung-Chul;Seo, Joung-Don;Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
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    • v.28 no.2
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    • pp.172-176
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    • 1994
  • As the Tc-99m-MIBI myocardial SPECT demonstrated wide application in the diagnosis of myocardial function, the quantitative and severity-dependent information is currently re quired. In this study, we proposed a computerized method for scoring the fixed defects in terms of extent-weighted severity and for identifying the reversibility in ischemic regions. At the first stage of this method, the transverse slices were reconstructed with 0.4 Nyquist freq. and order 5 Butterworth filter. From the oblique/sagittal slices, maximal count per pixel circumferential profiles were extracted for each sector, and then stress/redist. polar maps were normalized and plotted. For reversibility, the stress polar map was subtracted from the de-layed image and positive-valued pixels were categorized into three grades. The extent-weight-ed severity scores were calculated using the assigned grades and their number of pixels. This procedure was done automatically and the reversibility and severity scores were produced for each of the coronary territories (LAD, RCA, LCX) or any combination of these. Clinical ap-plication has shown that the changes In reversibility scores after PTCA were correlated linearly with the pre PTCA scores(r>0.8) in postinfarct cases as well as in angina, and severity scores of persistent defects in stress/rest SPECT study matched to the regional ejection fraction and visual analysis of regional wall motion of gated blood pool scan(r>0.6). We conclude that the computerized severity scoring method for the analysis of myocardial SPECT could be useful in the assessment of the myocardial ischemia and fixed defect.

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Validity of Peak Expiratory Flow for Assessing Reversible Airflow Obstruction (기류 가역성 평가에 있어서 최대호기유속 측정의 유용성)

  • Chol, Won-Il;Kwak, Jin-Ho;Kwon, Doo-Young;Han, Seung-Beom;Jeon, Young-June
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.4
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    • pp.522-529
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    • 2000
  • Backgrounds : Assessment of the presence and degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. The measurement of peak expiratory flow(PEF) is a simple, fast, and cheap method to assess the severity of obstruction and its degree of reversibility. Assessing the reversibility of airflow obstruction by peak expiratory flow(PEF) measurements is practicable in general practice, but its usefulness has not been well investigated. We compared PEF and $FEV_1$ in assessing reversibility of airflow obstruction in patients with chronic obstructive pulmonary disease or asthma and developed a practical criterion for assessing the presence of reversibility in general practice. Methods : PEF measurements were performed (Spirometry) in 80 patients(aged 24-78) with a history of asthma or chronic obstructive lung disease before and after the inhalation of 200 g salbutamol. The change in PEF was compared with the change in forced expiratory volume in one second($FEV_1$). Reversible airflow obstruction was analyzed according to American Thoracic Society(ATS) criteria. Results : A 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ reversibility were observed in 45%(36) of the patients. Relative operating characteristic(ROC) analysis showed that an absolute improvement in PEF of 30 l/min gave optimal discrimination between patients with reversible and irreversible airflow obstruction(the sensitivity and specificity of an increase of 30 l/min in detecting a 12% increase above the prebronchodilator value and a 200ml increase in either FVC or $FEV_1$ were 72.2% and 72.7% respectively, with a positive predictive value of 68.4%). Conclusions : Absolute changes in PEF can be used to diagnose reversible airflow obstruction.

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REVERSIBLE AND PSEUDO-REVERSIBLE RINGS

  • Huang, Juan;Jin, Hai-lan;Lee, Yang;Piao, Zhelin
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.5
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    • pp.1257-1272
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    • 2019
  • This article concerns the structure of idempotents in reversible and pseudo-reversible rings in relation with various sorts of ring extensions. It is known that a ring R is reversible if and only if $ab{\in}I(R)$ for $a,b{\in}R$ implies ab = ba; and a ring R shall be said to be pseudoreversible if $0{\neq}ab{\in}I(R)$ for $a,b{\in}R$ implies ab = ba, where I(R) is the set of all idempotents in R. Pseudo-reversible is seated between reversible and quasi-reversible. It is proved that the reversibility, pseudoreversibility, and quasi-reversibility are equivalent in Dorroh extensions and direct products. Dorroh extensions are also used to construct several sorts of rings which are necessary in the process.