• 제목/요약/키워드: Survival function

검색결과 839건 처리시간 0.025초

담도폐쇄 (Biliary Atresia)

  • 한석주
    • Advances in pediatric surgery
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    • 제17권1호
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    • pp.1-14
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    • 2011
  • Biliary atresia (BA) is an infantile cholestatic disease of progressive obliterative cholangiopathy with varying degrees of damage to both extra and intrahepatic bile ducts due to unknown causes. The diagnostic studies should be done to diagnose or exclude BA without unnecessary delay. Kasai portoenterostomy is the first choice of treatment for bile drainage from microscopic bile ductules present in the portal fibrous mass. The medical management after Kasai portoenterostomy should be done carefully to maintain bile excretion and prevent and treat complications Including cholangitis, hepatic fibrosis, portal hypertension and nutritional problem. The reported five years-survival rates after Kasai portoenterostomy range from 30 to 60 %. About 20 % of all patients undergoing Kasai portoenterostomy during infancy survive into adulthood with their native liver. Even if Kasai portoenterostomy remains as the first line of treatment In BA, liver transplantation serves as a good salvage treatment when portoenterostomy fails or liver function gradually deteriorates after initially successful establishment of bile flow, Overall 5-year survival rate in BA is about 90 % in recent series.

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Disruption of ATP binding destabilizes NPM/B23 and inhibits anti-apoptotic function

  • Choi, Joung-Woo;Lee, Sang-Bae;Ahn, Jee-Yin;Lee, Kyung-Hoon
    • BMB Reports
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    • 제41권12호
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    • pp.840-845
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    • 2008
  • Nucleophosmin/B23, a major nucleolar phosphoprotein, is overexpressed in actively proliferating cells. In this study, we demonstrate that B23 exclusively localizes in the nucleolus, whereas ATP depletion results in the redistribution of B23 throughout the whole nucleus and destabilizes B23 via caspase-3 mediated cleavage. Interestingly, ATP binding precedes PI(3,4,5)P3 binding at lysine 263 and ATP binding mutants fail to restore the anti-apoptotic functions of B23 in PC12 cells. Thus, the ATP-B23 interaction is required for the stability of the B23 protein and regulates cell survival, confining B23 within the nucleolus in PC12 cells.

시나리오 기반 환자 분배 및 의료진 할당을 위한 재난 대응 최적화 모형 연구 (Scenario-Based Optimization of Patient Distribution and Medical Resource Allocation in Disaster Response)

  • 진석호;김장엽;김경섭;정석재
    • 대한산업공학회지
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    • 제40권2호
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    • pp.151-162
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    • 2014
  • This study proposes an optimization model to plan the patient distribution and medical resource allocation considering the diverse characteristics of disaster. For reflecting the particularity of disaster response, we configured a few scenarios such as availability of emergency surgery of non-major medical staff and the change in number of patients estimated reflecting the uncertainty, urgency and convergence of disaster. And we finally tested the effects of the scenarios' combination on the objective function defined as maximum number of survival patients. Our experimental results are expected to highlight the significance of the proposed model as well as the applicability of scenarios under disaster response.

The transmuted GEV distribution: properties and application

  • Otiniano, Cira E.G.;de Paiva, Bianca S.;Neto, Daniele S.B. Martins
    • Communications for Statistical Applications and Methods
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    • 제26권3호
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    • pp.239-259
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    • 2019
  • The transmuted generalized extreme value (TGEV) distribution was first introduced by Aryal and Tsokos (Nonlinear Analysis: Theory, Methods & Applications, 71, 401-407, 2009) and applied by Nascimento et al. (Hacettepe Journal of Mathematics and Statistics, 45, 1847-1864, 2016). However, they did not give explicit expressions for all the moments, tail behaviour, quantiles, survival and risk functions and order statistics. The TGEV distribution is a more flexible model than the simple GEV distribution to model extreme or rare events because the right tail of the TGEV is heavier than the GEV. In addition the TGEV distribution can adjusted various forms of asymmetry. In this article, explicit expressions for these measures of the TGEV are obtained. The tail behavior and the survival and risk functions were determined for positive gamma, the moments for nonzero gamma and the moment generating function for zero gamma. The performance of the maximum likelihood estimators (MLEs) of the TGEV parameters were tested through a series of Monte Carlo simulation experiments. In addition, the model was used to fit three real data sets related to financial returns.

Crosstalk between RNA silencing and RNA quality control in plants

  • Yun Ju Kim
    • BMB Reports
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    • 제56권6호
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    • pp.321-325
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    • 2023
  • RNAs are pivotal molecules acting as messengers of genetic information and regulatory molecules for cellular development and survival. From birth to death, RNAs face constant cellular decision for the precise control of cellular function and activity. Most eukaryotic cells employ conserved machineries for RNA decay including RNA silencing and RNA quality control (RQC). In plants, RQC monitors endogenous RNAs and degrades aberrant and dysfunctional species, whereas RNA silencing promotes RNA degradation to repress the expression of selected endogenous RNAs or exogenous RNA derived from transgenes and virus. Interestingly, emerging evidences have indicated that RQC and RNA silencing interact with each by sharing target RNAs and regulatory components. Such interaction should be tightly organized for proper cellular survival. However, it is still elusive that how each machinery specifically recognizes target RNAs. In this review, we summarize recent advances on RNA silencing and RQC pathway and discuss potential mechanisms underlying the interaction between the two machineries.

On the comparison of cumulative hazard functions

  • Park, Sangun;Ha, Seung Ah
    • Communications for Statistical Applications and Methods
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    • 제26권6호
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    • pp.623-633
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    • 2019
  • This paper proposes two distance measures between two cumulative hazard functions that can be obtained by comparing their difference and ratio, respectively. Then we estimate the measures and present goodness of t test statistics. Since the proposed test statistics are expressed in terms of the cumulative hazard functions, we can easily give more weights on earlier (or later) departures in cumulative hazards if we like to place an emphasis on earlier (or later) departures. We also show that these test statistics present comparable performances with other well-known test statistics based on the empirical distribution function for an exponential null distribution. The proposed test statistic is an omnibus test which is applicable to other lots of distributions than an exponential distribution.

On simple estimation technique for the reliability of exponential lifetime model

  • Al-Hemyari, Z.A.;Al-Saidy, Obaid M.;Al-Ali, A.R.
    • International Journal of Reliability and Applications
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    • 제14권2호
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    • pp.79-96
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    • 2013
  • Exponential distribution plays a key role in engineering reliability and its applications. The exponential failure model has been studied for years. This article introduces two new preliminary test estimators for the reliability function (R(t)) in complete and censored samples from the exponential model with the use of a prior estimation (${\theta}_0$) of the mean (${\theta}$). The proposed preliminary test estimators are studied and compared numerically with the existing estimators. Computer-intensive calculations for bias and relative efficiency show that for, different values of levels of significance and for varying constants involved in the proposed estimators, the proposed estimators are far better than classical and existing estimators.

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Estimation of Hazard Function and its Associated Factors in Gastric Cancer Patients using Wavelet and Kernel Smoothing Methods

  • Ahmadi, Azadeh;Roudbari, Masoud;Gohari, Mahmood Reza;Hosseini, Bistoon
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권11호
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    • pp.5643-5646
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    • 2012
  • Background and Objectives: Increase of mortality rates of gastric cancer in Iran and the world in recent years reveal necessity of studies on this disease. Here, hazard function for gastric cancer patients was estimated using Wavelet and Kernel methods and some related factors were assessed. Materials and Methods: Ninety-five gastric cancer patients in Fayazbakhsh Hospital between 1996 and 2003 were studied. The effects of age of patients, gender, stage of disease and treatment method on patient's lifetime were assessed. For data analyses, survival analyses using Wavelet method and Log-rank test in R software were used. Results: Nearly 25.3% of patients were female. Fourteen percent had surgery treatment and the rest had treatment without surgery. Three fourths died and the rest were censored. Almost 9.5% of patients were in early stages of the disease, 53.7% in locally advance stage and 36.8% in metastatic stage. Hazard function estimation with the wavelet method showed significant difference for stages of disease (P<0.001) and did not reveal any significant difference for age, gender and treatment method. Conclusion: Only stage of disease had effects on hazard and most patients were diagnosed in late stages of disease, which is possibly one of the most reasons for high hazard rate and low survival. Therefore, it seems to be necessary a public education about symptoms of disease by media and regular tests and screening for early diagnosis.

Nox4-Mediated Cell Signaling Regulates Differentiation and Survival of Neural Crest Stem Cells

  • Lee, Ji-Eun;Cho, Kyu Eun;Lee, Kyung Eun;Kim, Jaesang;Bae, Yun Soo
    • Molecules and Cells
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    • 제37권12호
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    • pp.907-911
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    • 2014
  • The function of reactive oxygen species (ROS) as second messengers in cell differentiation has been demonstrated only for a limited number of cell types. Here, we used a well-established protocol for BMP2-induced neuronal differentiation of neural crest stem cells (NCSCs) to examine the function of BMP2-induced ROS during the process. We first show that BMP2 indeed induces ROS generation in NCSCs and that blocking ROS generation by pretreatment of cells with diphenyleneiodonium (DPI) as NADPH oxidase (Nox) inhibitor inhibits neuronal differentiation. Among the ROS-generating Nox isozymes, only Nox4 was expressed at a detectable level in NCSCs. Nox4 appears to be critical for survival of NCSCs at least in vitro as down-regulation by RNA interference led to apoptotic response from NCSCs. Interestingly, development of neural crest-derived peripheral neural structures in Nox4-/- mouse appears to be grossly normal, although Nox4-/- embryos were born at a sub-Mendelian ratio and showed delayed over-all development. Specifically, cranial and dorsal root ganglia, derived from NCSCs, were clearly present in Nox4-/- embryo at embryonic days (E) 9.5 and 10.5. These results suggest that Nox4-mediated ROS generation likely plays important role in fate determination and differentiation of NCSCs, but other Nox isozymes play redundant function during embryogenesis.

T2N0M0 비소세포성 폐암의 근치적 방사선치료 (Curative Radiation Therapy for T2N0M0 Non-small Cell Lung Cancer)

  • 박인규;김재철
    • Radiation Oncology Journal
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    • 제13권1호
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    • pp.19-26
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    • 1995
  • Purpose : Surgery is the treatment of choice for resectable non-small cell lung cancer. For patients who are medically unable to tolerate a surgical resection or who refuse surgery, radiation therapy is an acceptable alternative. A retrospective analysis of Patients with stage I non-samll cell lung cancer treated with curative radiation therapy was performed to determine the results of curative radiation therapy and patterns of failure, and to identify factors that may influence survival. Materials and Methods : From 1986 through 1993, 39 Patients with T2N0M0 non-small cell lung cancer were treated with curative radiation therapy at department of radiation oncology, Kyungpook national university hospital. All Patients were not candidates for surgical resection because of either Patient refusal (16 patients), poor pulmonary function (12 patients), old age (7 patients), Poor Performance (2 patients) or coexisting medical disease (2 patients). Median age of patients was 67 years. Histologic cell type was squamous cell carcinoma in 36, adenocarcinoma in 1, large cell carcinoma in 1 and mucoepidermoid carcinoma in 1. All patients were treated with megavoltage irradiation and radiation dose ranged from 5000cgy to 6150cGy with a median dose of 6000cGy. The median follow-up was 17 months with a range of 4 to 82 months, Survival was measured from the date therapy initiated. Results : The overall survival rate for entire Patients was $40.6\%$ at 2 years and $27.7\%$ at 3 years, with a median survival time of 21 months. The disease-free survival at 2 and 3 years was $51.7\%$ and $25.8\%$, respectively. Of evaluable 20 patients with complete response, 15 patients were considered to have failed. Of these, 13 patients showed local failure and 2 patients failed distantly. Response to treatment (p=0.0001), tumor size (p=0.0019) and age (p=0.0247) were favorably associated with overall survival. Only age was predictive for disease-free survival (p = 0.0452). Conclusion : Radiation therapy is an effective treatment for small (less than 3cm) tumors, and should be offered as an alternative to surgery in elderly or infirm patients. Since local failure is the prominent Patterns of relapse, potential methods to improve local control with radiation therapy are discussed.

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