• Title/Summary/Keyword: Cox's function

Search Result 60, Processing Time 0.026 seconds

The Effects of a Horticultural Program based on Cox's Interaction Model on Ability for Daily Life and Depression in Older Patients with Mild Dementia (Cox의 상호작용이론을 근거로 한 원예활동 프로그램이 경증치매노인의 일상생활수행능력 및 우울에 미치는 효과)

  • Yoon, Mi Jin;Sung, Kyung Mi
    • The Korean Journal of Rehabilitation Nursing
    • /
    • v.20 no.1
    • /
    • pp.12-21
    • /
    • 2017
  • Purpose: This study attempts to examine the effects of a horticultural program on activities of daily living (ADL) and depression among older patients with mild dementia. Methods: This study adopted a quasi-experimental design-based nonequivalent control group pretest and posttest design, enrolling 30 older patients with mild dementia. The Korean Form of Geriatric Depression Scale was utilized, while the data was collected from the experimental group for 60 minutes, twice weekly for 6 weeks in 12 sessions. ADL and depression were assessed for both the experimental and the control group. Overall functions were assessed only for the experimental group. Results: The experimental group showed improvement in physical function, cognitive function, as well as psychological, emotional function and social function following each session (p<.001). The horticulture program was effective in both ADL ($Z^2=5.65$, p<.001) and depression (t=-5.24, p<.001). Conclusion: In this study, the horticultural therapy based on the Cox's interaction model had positive effects for older patients with mild dementia. Therefore, horticultural therapy may be commendably applied to older patients with mild dementia as a nursing intervention.

SAR of COX-2 Inhibitors (COX-2 억제제의 구조-활성)

  • 권순경
    • Biomolecules & Therapeutics
    • /
    • v.9 no.2
    • /
    • pp.69-78
    • /
    • 2001
  • Cyclooxygenase (COX) is an enzyme, which catalyzes the production of prostaglandins from arachi-donic acid and exists in two isoforms (COX-1 and COX-2). COX-1 is involved in the maintenance of physiological functions such as platelet aggregation, cytoprotection in the stomach and maintenance of normal kidney function. COX-2 is induced significantly in vivo under inflammatory conditions. COX-1 and COX-2 serve different physiological and pathological functions. All commercially available nonsteroidal antiinflammatory drugs (NSAIDS) are inhibitors of both COX-1 and COX-2. Therefore, selective inhibitors of COX-2 may be effective antiinflammatory agents without the ulcerogenic effects associated with current NSAms. Since the mid 1990s, a number of reports have been appeared on the preparation and biological activity of selective COX-2 inhibitors. Recently celecoxib, and rofecoxib, the representative COX-2 inhibitors, are introduced in the drug market. In this paper the relationship of structure-activity for selective COX-2 inhibitors is reviewed.

  • PDF

Comparison of Survival Function Estimators for the Cox's Regression Model using Bootstrap Method (Cox 회귀모형(回歸模型)에서 붓스트랩방법(方法)에 의한 생존함수추정량(生存函數推定量)의 비교연구(比較硏究))

  • Cha, Young-Joon
    • Journal of the Korean Data and Information Science Society
    • /
    • v.4
    • /
    • pp.1-11
    • /
    • 1993
  • The Cox's regression model is frequently used for covariate effects in survival data analysis, But, much of the statistical work has focused on asymptotic behavior so the small sample evaluation has been neglected. In this paper, we compare the small or moderate sample performances of the survival function estimators for the Cox's regression model using bootstrap method. The smoothed PL type estimator and the Link estimator are slightly better than corresponding the PL type estimator and the Nelson type estimator in the sense of the achieved error rates.

  • PDF

The Performance Analysis of Digital Watermarking based on Merging Techniques

  • Ariunzaya, Batgerel;Chu, Hyung-Suk;An, Chong-Koo
    • Journal of the Institute of Convergence Signal Processing
    • /
    • v.12 no.3
    • /
    • pp.176-180
    • /
    • 2011
  • Even though algorithms for watermark embedding and extraction step are important issue for digital watermarking, watermark selection and post-processing can give us an opportunity to improve our algorithms and achieve higher performance. For this reason, we summarized the possibilities of improvements for digital watermarking by referring to the watermark merging techniques rather than embedding and extraction algorithms in this paper. We chose Cox's function as main embedding and extraction algorithm, and multiple barcode watermarks as a watermark. Each bit of the multiple copies of barcode watermark was embedded into a gray-scale image with Cox's embedding function. After extracting the numbers of watermark, we applied the watermark merging techniques; including the simple merging, N-step iterated merging, recover merging and combination of iterated-recover merging. Main consequence of our paper was the fact of finding out how multiple barcode watermarks and merging techniques can give us opportunities to improve the performance of algorithm.

Estimation of hazard function and hazard change-point for the rectal cancer data (직장암 데이터에 대한 위험률 함수 추정 및 위험률 변화점 추정)

  • Lee, Sieun;Shim, Byoung Yong;Kim, Jaehee
    • Journal of the Korean Data and Information Science Society
    • /
    • v.26 no.6
    • /
    • pp.1225-1238
    • /
    • 2015
  • In this research, we fit various survival models and conduct tests and estimation for the hazard change-point with the rectal cancer data. By the log-rank tests, at significance level ${\alpha}=0.10$, survival functions are significantly different according to the uniporter of glucose (GLUT1), clinical stage (cstage) and pathologic stage (ypstage). From the Cox proportional hazard model, the most significant covariates are GLUT1 and ypstage. Assuming that the rectal cancer data follows the exponential distribution, we estimate one hazard change-point using Matthews and Farewell (1982), Henderson (1990) and Loader (1991) methods.

Estimation of conditional mean residual life function with random censored data (임의중단자료에서의 조건부 평균잔여수명함수 추정)

  • Lee, Won-Kee;Song, Myung-Unn;Jeong, Seong-Hwa
    • Journal of the Korean Data and Information Science Society
    • /
    • v.22 no.1
    • /
    • pp.89-97
    • /
    • 2011
  • The aims of this study were to propose a method of estimation for mean residual life function (MRLF) from conditional survival function using the Buckley and James's (1979) pseudo random variables, and then to assess the performance of the proposed method through the simulation studies. The mean squared error (MSE) of proposed method were less than those of the Cox's proportional hazard model (PHM) and Beran's nonparametric method for non-PHM case. Futhermore in the case of PHM, the MSE's of proposed method were similar to those of Cox's PHM. Finally, to evaluate the appropriateness of practical use, we applied the proposed method to the gastric cancer data. The data set consist of the 1, 192 patients with gastric cancer underwent surgery at the Department of Surgery, K-University Hospital.

A Study on the Survival Probability and Survival Factors of Small and Medium-sized Enterprises Using Technology Rating Data (기술평가 자료를 이용한 중소기업의 생존율 추정 및 생존요인 분석)

  • Lee, Young-Chan
    • Knowledge Management Research
    • /
    • v.11 no.2
    • /
    • pp.95-109
    • /
    • 2010
  • The objectives of this study are to identify the survival function (hazard function) of small and medium enterprises by using technology rating data for the companies guaranteed by Korea Technology Finance Corporation (KOTEC), and to figure out the factors that affects their survival. To serve the purposes, this study uses Kaplan-Meier Analysis as a non-parametric method and Cox proportional hazards model as a semi-parametric one. The 17,396 guaranteed companies that assessed from July 1st in 2005 to December 31st in 2009 are selected as samples (16,504 censored data and 829 accident data). The survival time is computed with random censoring (Type III) from July in 2005 as a starting point. The results of the analysis show that Kaplan-Meier Analysis and Cox proportional hazards model are able to readily estimate survival and hazard function and to perform comparative study among group variables such as industry and technology rating level. In particular, Cox proportional hazards model is recognized that it is useful to understand which technology rating items are meaningful to company's survival and how much they affect it. It is considered that these results will provide valuable knowledge for practitioners to find and manage the significant items for survival of the guaranteed companies through future technology rating.

  • PDF

On the analysis of multistate survival data using Cox's regression model (Cox 회귀모형을 이용한 다중상태의 생존자료분석에 관한 연구)

  • Sung Chil Yeo
    • The Korean Journal of Applied Statistics
    • /
    • v.7 no.2
    • /
    • pp.53-77
    • /
    • 1994
  • In a certain stochastic process, Cox's regression model is used to analyze multistate survival data. From this model, the regression parameter vectors, survival functions, and the probability of being in response function are estimated based on multistate Cox's partial likelihood and nonparametric likelihood methods. The asymptotic properties of these estimators are described informally through the counting process approach. An example is given to likelihood the results in this paper.

  • PDF

Feedback Control of Cyclooxygenase-2 Expression by Prostaglandin E2 in Rheumatoid Synoviocytes

  • Min, So-Youn;Jung, Young Ok;Do, Ju-Ho;Kim, So-Yang;Kim, Jeong-Pyo;Cho, Chul-Soo;Kim, Wan-Uk
    • IMMUNE NETWORK
    • /
    • v.3 no.3
    • /
    • pp.201-210
    • /
    • 2003
  • Objective: The role of prostaglandin $E_2$ (PGE2) in the etiopathogenesis of immune and inflammatory diseases has become the subject of recent debate. To determine the role of PGE2 in rheumatoid arthritis (RA), we tested the effect of exogenous PGE2 on the production of cyclooxygenase-2 (COX-2) by rheumatoid synoviocytes. Methods: Fibroblast-like synoviocytes (FLS) were prepared from the synovial tissues of RA patients, and cultured in the presence of PGE2. The COX-2 mRNA and protein expression levels were determined by RT-PCR and Western blot analysis, respectively. The PGE2 receptor subtypes in the FLS were analyzed by RT-PCR. Electrophoretic mobility shift assay (EMSA) was used to measure the NF-${\kappa}B$ binding activity for COX-2 transcription. The in vivoeffect of PGE2 on the development of arthritis was also tested in collagen induced arthritis (CIA) animals. Results: PGE2 ($10^{-11}$ to $10^{-5}M$) dose-dependently inhibited the expression of COX-2 mRNA and the COX-2 protein stimulated with IL-$1{\beta}$, but not COX-1 mRNA. NS-398, a selective COX-2 inhibitor, displayed an additive effect on PGE2-induced COX-2 downregulation. The FLS predominantly expressed the PGE2 receptor (EP) 2 and EP4, which mediated the COX-2 suppression by PGE2. Treatment with anti-IL-10 monoclonal antibodies partially reversed the PGE2-induced suppression of COX-2 mRNA, suggesting that IL-10 may be involved in modulating COX-2 by PGE2. Experiments using an inducer and an inhibitor of cyclic AMP (cAMP) suggest that cAMP is the major intracellular signal that mediates the regulatory effect of PGE2 on COX-2 expression. EMSA revealed that PGE2 inhibited the binding of NF-${\kappa}B$ in the COX-2 promoter via a cAMP dependent pathway. In addition, a subcutaneous injection of PGE2 twice daily for 2 weeks significantly reduced the incidence and severity of CIA as well as the production of IgG antibodies to type II collagen. Conclusion: Our data suggest that overproduced PGE2 in the RA joints may function as an autocrine regulator of its own synthesis by inhibiting COX-2 production and may, in part, play an anti-inflammatory role in the arthritic joints.

A Study on the Conditional Survival Function with Random Censored Data

  • Lee, Won-Kee;Song, Myung-Unn
    • Journal of the Korean Data and Information Science Society
    • /
    • v.15 no.2
    • /
    • pp.405-411
    • /
    • 2004
  • In the analysis of cancer data, it is important to make inferences of survival function and to assess the effects of covariates. Cox's proportional hazard model(PHM) and Beran's nonparametric method are generally used to estimate the survival function with covariates. We adjusted the incomplete survival time using the Buckley and James's(1979) pseudo random variables, and then proposed the estimator for the conditional survival function. Also, we carried out the simulation studies to compare the performances of the proposed method.

  • PDF