907 resultados para Colorectal neoplasms (Experiments)


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Microarray data analysis is one of data mining tool which is used to extract meaningful information hidden in biological data. One of the major focuses on microarray data analysis is the reconstruction of gene regulatory network that may be used to provide a broader understanding on the functioning of complex cellular systems. Since cancer is a genetic disease arising from the abnormal gene function, the identification of cancerous genes and the regulatory pathways they control will provide a better platform for understanding the tumor formation and development. The major focus of this thesis is to understand the regulation of genes responsible for the development of cancer, particularly colorectal cancer by analyzing the microarray expression data. In this thesis, four computational algorithms namely fuzzy logic algorithm, modified genetic algorithm, dynamic neural fuzzy network and Takagi Sugeno Kang-type recurrent neural fuzzy network are used to extract cancer specific gene regulatory network from plasma RNA dataset of colorectal cancer patients. Plasma RNA is highly attractive for cancer analysis since it requires a collection of small amount of blood and it can be obtained at any time in repetitive fashion allowing the analysis of disease progression and treatment response.

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The progress in microsystem technology or nano technology places extended requirements to the fabrication processes. The trend is moving towards structuring within the nanometer scale on the one hand, and towards fabrication of structures with high aspect ratio (ratio of vertical vs. lateral dimensions) and large depths in the 100 µm scale on the other hand. Current procedures for the microstructuring of silicon are wet chemical etching and dry or plasma etching. A modern plasma etching technique for the structuring of silicon is the so-called "gas chopping" etching technique (also called "time-multiplexed etching"). In this etching technique, passivation cycles, which prevent lateral underetching of sidewalls, and etching cycles, which etch preferably in the vertical direction because of the sidewall passivation, are constantly alternated during the complete etching process. To do this, a CHF3/CH4 plasma, which generates CF monomeres is employed during the passivation cycle, and a SF6/Ar, which generates fluorine radicals and ions plasma is employed during the etching cycle. Depending on the requirements on the etched profile, the durations of the individual passivation and etching cycles are in the range of a few seconds up to several minutes. The profiles achieved with this etching process crucially depend on the flow of reactants, i.e. CF monomeres during the passivation cycle, and ions and fluorine radicals during the etching cycle, to the bottom of the profile, especially for profiles with high aspect ratio. With regard to the predictability of the etching processes, knowledge of the fundamental effects taking place during a gas chopping etching process, and their impact onto the resulting profile is required. For this purpose in the context of this work, a model for the description of the profile evolution of such etching processes is proposed, which considers the reactions (etching or deposition) at the sample surface on a phenomenological basis. Furthermore, the reactant transport inside the etching trench is modelled, based on angular distribution functions and on absorption probabilities at the sidewalls and bottom of the trench. A comparison of the simulated profiles with corresponding experimental profiles reveals that the proposed model reproduces the experimental profiles, if the angular distribution functions and absorption probabilities employed in the model is in agreement with data found in the literature. Therefor the model developed in the context of this work is an adequate description of the effects taking place during a gas chopping plasma etching process.

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KAM is a computer program that can automatically plan, monitor, and interpret numerical experiments with Hamiltonian systems with two degrees of freedom. The program has recently helped solve an open problem in hydrodynamics. Unlike other approaches to qualitative reasoning about physical system dynamics, KAM embodies a significant amount of knowledge about nonlinear dynamics. KAM's ability to control numerical experiments arises from the fact that it not only produces pictures for us to see, but also looks at (sic---in its mind's eye) the pictures it draws to guide its own actions. KAM is organized in three semantic levels: orbit recognition, phase space searching, and parameter space searching. Within each level spatial properties and relationships that are not explicitly represented in the initial representation are extracted by applying three operations ---(1) aggregation, (2) partition, and (3) classification--- iteratively.

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In a recent experiment, Freedman et al. recorded from inferotemporal (IT) and prefrontal cortices (PFC) of monkeys performing a "cat/dog" categorization task (Freedman 2001 and Freedman, Riesenhuber, Poggio, Miller 2001). In this paper we analyze the tuning properties of view-tuned units in our HMAX model of object recognition in cortex (Riesenhuber 1999) using the same paradigm and stimuli as in the experiment. We then compare the simulation results to the monkey inferotemporal neuron population data. We find that view-tuned model IT units that were trained without any explicit category information can show category-related tuning as observed in the experiment. This suggests that the tuning properties of experimental IT neurons might primarily be shaped by bottom-up stimulus-space statistics, with little influence of top-down task-specific information. The population of experimental PFC neurons, on the other hand, shows tuning properties that cannot be explained just by stimulus tuning. These analyses are compatible with a model of object recognition in cortex (Riesenhuber 2000) in which a population of shape-tuned neurons provides a general basis for neurons tuned to different recognition tasks.

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This paper presents the distributed environment for virtual and/or real experiments for underwater robots (DEVRE). This environment is composed of a set of processes running on a local area network composed of three sites: 1) the onboard AUV computer; 2) a surface computer used as human-machine interface (HMI); and 3) a computer used for simulating the vehicle dynamics and representing the virtual world. The HMI can be transparently linked to the real sensors and actuators dealing with a real mission. It can also be linked with virtual sensors and virtual actuators, dealing with a virtual mission. The aim of DEVRE is to assist engineers during the software development and testing in the lab prior to real experiments

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Introducción:Los individuos en quienes se realiza el sugarbaker tienen diagnósticos tumorales bien caracterizados. Actualmente no se dispone en la literatura médica universal de comparadores previos que permitan estimar la morbilidad relacionada específicamente con procesos infecciosos en pacientes sometidos al procedimiento, por tanto se presenta la caracterización de procesos febriles e infecciosos en el postoperatorio de la cohorte de pacientes intervenidos en la FSFB y de los factores de riesgo asociados a su manifestación. Métodos:Estudio descriptivo con componente analítico de una cohorte ambidireccional compuesta por pacientes intervenidos en la FSFB mediante el procedimiento de Sugarbaker. Resultados:En total se incluyeron en el estudio 53 pacientes consecutivos (37mujeres y 16hombres), quienes fueron llevados al procedimiento de peritonectomía radical más quimioterapia hipertérmica intraperitoneal entre el mes de nov/2007 y jun/2012 en el Hospital-Universitario Fundación Santa Fe de Bogotá. Los desenlaces de morbilidad asociada al procedimiento fueron caracterizados, indicando que las principales causas de morbilidad son los eventos tromboticos y las infecciones. Se caracterizaron como estadísticamente significativos para estancia hospitalaria el requerimiento transfusional (r=0,451, p=0,001), colecistectomía (p=0,016), el riesgo anestésico ASA≥3 (p=0,03), entre otros. El perfil de infección mostró relación estadísticamente significativa con resecciones de órganos específicas (p<0,05 para colectomía derecha [OR=5,3], colecistectomía [OR=21,8] y esplenectomía [OR=4,2]), el riesgo anestésico ASA≥3 (OR=1,2, p=0,036), anemia (OR=7,1, p=0,004), fístula (OR=5,2, p=0,036), entre otros. Conclusiones: El procedimiento de Sugarbaker es eficaz y seguro en nuestra institución. Se requiere de más estudios en poblaciones diversas que permitan comprender el comportamiento de las infecciones en la población sometida al procedimiento.

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Objective: To explore and define the utility of different strategies for primary prevention (ASA, diet, physical activity) and strategies of screening test (FOBT, sigmoidoscopy, colonoscopy, etc.) for colorectal cancer. Data source: Databases consulted were MEDLINE (1966 to 2006), DARE (1980 to 2006), Cochrane Central Register of Controlled Trials, Cochrane Collaboration’s Registry of Clinical Trials, Cochrane Database of Systematic Reviews and LILACS. Study selection: Studies such clinical trial, cohort and case-control studies of the effectiveness of tests for screening and primary prevention adenoma and colorectal cancer were identified by two reviewers. Data Extraction: The extraction of data and its evaluation is done in most of the process so paired. Limitations: Not strictly complies with the methodology of a systematic review and therefore reproducibility is questionable, the conclusions of this study should be extrapolated with caution. Conclusions: The major strategy of screening on the effectiveness of early detection of premalignant lesions or cancer is colonoscopy every 5 years, however it is necessary to evaluate this measure cost-effectiveness studies. For primary prevention, aspirin and cyclooxygenase-2 inhibitors reduce the incidence of colorectal adenomas. Aspirin can reduce colorectal cancer incidence. However, these medications may be associated with a significant risk of cardiovascular events and gastrointestinal bleeding. The balance between risks and benefits must be evaluated in future studies.

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