Advanced Statistical Methods for Efficient Evaluation of Biomedical Data

Import 05/08/2014Analýza přežití zahrnuje soubor vyspělých statistických metod využívaných především k analýze dat v cenzorovaném tvaru modelujících dobu do výskytu události. Ta vznikají v situacích, kdy je informace o pozorovaném čase z náhodných příčin neúplná, např. při modelování časů přežití pacientů v medicínských studiích, při určení životnosti strojů a součástek v analýze spolehlivosti nebo doby nezaměstnanosti v analýze času trvání. Pole působnosti analýzy přežití je proto velmi široké a zahrnuje odvětví medicíny, inženýrství, ekonomie, sociologie nebo demografie. V této práci byly metody analýzy přežití využity k vyhodnocení medicínských zprava cenzorovaných dat 876 pacientů, kteří podstoupili chirurgickou operaci kolorektálního karcinomu ve Fakultní nemocnici Ostrava. Ta je prováděna pomocí dvou různých chirurgických postupů – otevřeného a laparoskopického. V práci bylo provedeno porovnání obou chirurgických postupů z hlediska rizika mortality za účelem nalezení odpovědi na otázku, zda některý z nich garantuje pacientům delší dobu přežití. Dále byly analyzovány nejistoty v souvislosti s rizikem mortality. K vypracování byly využity následující metody vycházející ze všech odvětví analýzy přežití: 1. Klasický neparametrický přístup zastoupený Kaplan-Meierovým a Nelson-Aalenovým odhadem funkce přežití ve spojení s pásmy spolehlivosti. 2. Moderní neparametrický přístup reprezentovaný neparametrickou prediktivní indukcí, která ke kvantifikaci nejistot využívá intervalový rozdíl odhadu dolní a horní pravděpodobnosti. 3. Tradiční log-rank test a neparametrické prediktivní porovnání přežití u skupin pacientů rozdělených podle zvoleného chirurgického postupu. 4. Semiparametrický Coxův proporciální hazardní model, který vyhodnocuje vliv na přežití dalších doplňkových proměnných, včetně jejich interakcí. 5. Weibullův parametrický model s tvarem základní hazardní funkce, který dokáže velmi dobře modelovat dobu přežití pacientů.Survival analysis is a set of advanced statistical methods for the analysis of time to event data, typically consisting of observed event times and right-censoring times. This type of data may arise from various situations: the survival times of patients in medical trials, the lifetimes of machine components in industrial reliability, studies of duration of periods of unemployment in duration modeling. The possible fields of applications of those methods are therefore in medicine, engineering, economics, sociology or demography. In this thesis the methods of survival analysis have been used to evaluate medical right-censored data of 876 patients who underwent colectomy in the University Hospital of Ostrava. There are used two basic surgery techniques for the colectomy: either open or laparoscopic. The comparison of the two techniques in the context of mortality has been done in order to answer the question: is there a type of surgery technique which guarantees longer overall survival time? The next step has been the analysis of the uncertainty related to the risk of mortality. For analyses and comparison have been used following methods: 1. The nonparametric approach with the standard Kaplan-Meier and the Nelson-Aalen estimator of survival function including confidence interval for survival function. 2. The innovative nonparametric approach, represented by Nonparametric Predictive Inference, which uses lower and upper probabilities for quantifying uncertainty providing a model of predictive survival function. 3. The traditional log-rank test and the nonparametric predictive comparison of two groups of lifetime data, which have been compared to evaluate risk of mortality in the context of mentioned surgery techniques. 4. The semiparametric Cox proportional hazard model has been used for analyzing the influence of other patients characteristics. 5. The parametric Weibull model, used because of the fact that the hazard function of human life is often described as being “bathtub shaped”.Prezenční470 - Katedra aplikované matematikyvyhově

Variability of spatial temporal gait parameters and center of pressure displacements during gait in elderly fallers and nonfallers: A 6-month prospective study

Considering that most of the falls in elderly population arise during walking, tests derived from walking performance would be desirable for comprehensive fall risk assessment. The analysis of spatial temporal parameters and the center of pressure displacement, which represents the interaction between the human body and the ground, would be beneficial. The aim of this study was to compare spatial temporal gait parameters and their variability and the variability of the center of pressure displacement between elderly fallers and nonfallers during gait at self-selected, defined and fast speeds. A prospective study design was used. At the baseline, measurements of ground reaction force during gait at self-selected, defined and fast walking speeds by two force plates were performed. In addition, the Tinetti balance assessment tool, the Falls Efficacy Scale-International and the Activities-Specific Balance Confidence Scale were used. Mean and coefficient of variation of spatial temporal gait parameters and standard deviations of center of pressure displacement during loading response, midstance, terminal stance and preswing phases were calculated. Comparison of the fallers and nonfallers exhibited no significant difference in clinical tool, scales or spatial temporal parameters. Compared to nonfallers’ increased variability of walking speed at self-selected and defined speed, step width at fast walking speed and center of pressure displacement during preswing phase in medial-lateral directions at defined walking speed was found in fallers. However, application of the Holm-Bonferroni procedure for multiple comparisons exhibited no significant effect of group in any of the gait parameters. In general, our study did not observe an effect of group (fallers vs. nonfallers) on variability of spatial temporal parameters and center of pressure movement during gait. However, walking speed, step width as well as standard deviation of COP displacement in the medial-lateral direction during preswing exhibited a certain potential for distinguishing between elderly fallers and nonfallers.Web of Science122art. no. e017199

HyperLoom: A platform for defining and executing scientific pipelines in distributed environments

Real-world scientific applications often encompass end-to-end data processing pipelines composed of a large number of interconnected computational tasks of various granularity. We introduce HyperLoom, an open source platform for defining and executing such pipelines in distributed environments and providing a Python interface for defining tasks. HyperLoom is a self-contained system that does not use an external scheduler for the actual execution of the task. We have successfully employed HyperLoom for executing chemogenomics pipelines used in pharmaceutic industry for novel drug discovery.6

Role of orthoptics and scoring system for orbital floor blowout fracture: surgical or conservative treatment

AIM: To assess the role of orthoptics in referring patients with orbital floor blowout fracture (OFBF) for conservative or surgical treatment and based on the results, to propose a scoring system for such decision making. METHODS: A retrospective analysis of 69 patients with OFBF was performed (35 treated conservatively, 34 surgically). The role of orthoptics in referring to surgery or conservative treatment was retrospectively evaluated, the factors with the highest significance for decision making were identified, and a scoring system proposed using Logistic regression. RESULTS: According to defined criteria, the treatment was unsuccessful in 2 (6%) surgically treated and only in one (3%) conservatively treated patient. The proposed scoring system includes the defect size and several values resulting from the orthoptic examination, the elevation of the eyebulb measured on Lancaster screen being the most significant. CONCLUSION: The study demonstrates the benefits of orthoptic examination when making decisions on conservative or surgical treatment and for diagnosing ocular motility disorder (with or without binocular diplopia) in OFBF patients. The proposed scoring system could, following verification in a prospective study, become a valuable adjunctive tool.Web of Science14121934192

Metformin treatment for diabetes mellitus correlates with progression and survival in colorectal carcinoma

BACKGROUND: Diabetes mellitus is unfavorably associated with cancer risk. The purpose of this multi-disciplinary project was to evaluate a possible association of diabetes mellitus and other comorbidities and their treatment with progression of colorectal cancer. PATIENTS AND METHODS: We investigated the correlation between pathological characteristics and clinical course, including comorbidities in 1004 Czech patients diagnosed and surgically treated for colorectal adenocarcinoma (CRC) between 1999 and 2016. RESULTS: In our data set, CRC patients treated with metformin due to coexisting diabetes mellitus type 2 (T2DM) developed fewer distant metastases which clinically correlates with slower CRC progression. Survival in metformin subgroup was longer, particularly in men with CRC. Osteoporosis may be a negative factor of survival in CRC patients. CONCLUSIONS: Our findings also indicate that aging, higher tumor grade and TNM stage, coexistence of selected endocrine disorders, and metabolic abnormalities may change the tumor microenvironment and impact survival in colorectal cancer, although mechanism of these observations yet to be explained. Patients with diabetes mellitus type 2 treated with metformin may represent the altered microenvironment with specifically tuned metabolic molecular responses and with various epigenetic characteristics. More awareness and increased understanding of the mechanisms underlying the positive effect of metformin on patients' survival could offer insight into new treatment methods and permit more individualized treatment plans.Web of Science13239238

Sound-absorbing and thermal-insulating properties of cement composite based on recycled rubber from waste tires

This article describes an experimental study aimed at investigating the potential use of recycled rubber granulate from waste tires of fractions 0/1 and 1/3 mm in cement composites as a 100% replacement for natural aggregates. The use of waste in the development and production of new building materials represents an important aspect for the sustainability and protection of the environment. This article is focused on the sound-absorbing and thermal-insulating properties of experimental cement composites based on recycled rubber from waste tires. The article describes the grain characteristics of recycled rubber, sound absorption capacity, thermal conductivity and strength characteristics. The results of this research show that the total replacement of natural aggregate with recycled rubber in cement composites is possible. Replacing natural aggregate with recycled rubber has significantly improved the thermal and acoustic properties of the prepared cement composites, however, at the same time; there was also the expected decrease in the strength characteristics due to the elasticity of rubber.Web of Science116art. no. 272

Simulační model abrazivního kapalinového paprsku

Prezenční457 - Katedra aplikované matematikyNeuveden

Quadrature formulas for the effective numerical solution of transport equations

Import 29/09/2010Metoda hraničních zdrojů je integrální metoda představená na konci šedesátých let dvacátého století pro řešení jednorozměrných jedno-rychlostních neutronových transportních rovnic. V současnosti se jedná o jednu z nejpřesnějších metod pro řešení transportních rovnic v po částech homogenním prostředí. Tato metoda je ovšem výpočetně náročná, protože je nutné vyhodnotit velké množství Legendrových úhlových momentů přidružené Greenovy funkce, které jsou integrálem ze součinu Chandrasekharových polynomů a složité váhové funkce, která zahrnuje různé singularity. Cílem této práce je prostudovat daný integrand, analyzovat možné singularity a implementovat vybrané kvadraturní vzorce. Výsledky řešení vybraných modelových úloh budou porovnány v závislosti na dosažené rychlosti a přesnosti.The Boundary Sources Method (BSM) is an integral method introduced in the late 1960s for solving one-dimensional one-velocity neutron transport problems. It is probably the most accurate transport solution method available today for solving piecewise homogenous transport problems. Nevertheless the method is computationally expensive due to the numerical evaluation of a large number of Legendre’s angular moments of the associated Green’s function, which are integrals of product of Chandrasekhar polynomials with a complicated weight function presenting a variety of singularities. The aim of this thesis is to study the integrand and the singularities and to implement selected numerical methods for the numerical quadrature. Result of test cases, in terms of speed and numerical precision, will be presented and discussed.457 - Katedra aplikované matematikyvýborn

Role of the Probation and Mediation Service in the Penitentiary and Post-penitentiary Care

Následující práce popisuje činnost Probační a mediační služby ČR jako instituci pomáhající lidem, kteří se dostali do konfliktu s trestnou činností. Zabývá se tématikou alternativních trestů, penitenciární a postpenitenciární péče. Vystihuje rozdíl mezi restorativní a retributivní justicí. Zpracovává informace o povědomí lidí Pardubického kraje o Probační a mediační službě ČR.The following work is describing activity of the Probation and Mediation Service as an institution to help people who run afoul of criminal activity. It deals with themes of alternative punishments, the penitentiary and post-penitentiary care. It expressing the difference between restorative and retributive justice. The work is processing information about people's awareness of the Pardubice Region about the Probation and Mediation Service.Katedra věd o výchov