Fuzzy modeling in symptomatic HIV virus infected population

This paper introduces a model for the evolution of positive HIV population and manifestation of AIDS (acquired immunideficiency syndrome). The focus is on the nature of the transference rate of HIV to AIDS. Expert knowledge indicates that the transference rate is uncertain and depends strongly on the viral load and the CD4+ level of the infected individuals. Here, we suggest to view the transference rate as a fuzzy set of the viral load and CD4+ level values. In this case the dynamic model results in a fuzzy model that preserves the biological meaning and nature of the transference rate lambda. Its behavior fits the natural history of HIV infection reported in the medical science domain. The paper also includes a comparison between the fuzzy model and a classic Anderson's model using data reported in the literature. (C) 2004 Society for Mathematical Biology. Published by Elsevier Ltd. All rights reserved.6661597162

Cellular automata with fuzzy parameters in microscopic study of positive HIV individuals

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The aim of this paper is to introduce a model to simulate the evolution of HIV in the bloodstream of positive individuals subject to medical treatment and monitoring of the medication potency and treatment adhesion. For this purpose, a cellular automata approach coupled with fuzzy set theory is developed to study the HIV evolution. The study is conducted using two cellular automata models in two corresponding steps. The first step concerns HIV dynamics in individuals with no antiretroviral therapy. In this case, the trajectory developed by the cellular automaton model depicts all phases shown in the known history of HIV dynamics. The main purpose of the first step is to serve as a model validation step. The second step extends the model developed in the first step to consider HIV dynamics in individuals under antiretroviral therapy. The effects of antiretroviral therapy in the cellular automaton model are modeled using a fuzzy rule-based system with two inputs, the medication potency and treatment adhesion rate of the individuals to the therapy. The fuzzy rule-based system is used to compute the number of HIV infected CD4+ cells and the viral replication. The results developed by the cellular automaton model with antiretroviral therapy are close to the ones reported in the literature and agree with the behavior expected by experts [J. Guedj, R. Thiebaut, D. Commenges, Practical identifiability of HIV dynamics models, Bulletin of Mathematical Biology 69 (8) (2007) 2493-2513], [R. A. Filter, X. Xia, C. M. Gray, Dynamic HIV/AIDS parameter estimation with application to a vaccine readiness study in southern Africa, IEEE Transactions on Biomedical Engineering 52 (5) (2005) 784-791] and [D. A. Ouattara, M. J. Mhawej, C. H. Moog, Clinical tests of therapeutical failures based on mathematical modeling of the HIV infection, Systems Biology (2008) 230-241 (special issue)]. (C) 2009 Elsevier Ltd. All rights reserved.50416713244Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG)Research Foundation of the State of Minas Gerais [CEX-109/04]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Brazilian National Research Council [152068/2007-4]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Research Foundation of the State of Sao Paulo [06/05920-7]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Research Foundation of the State of Minas Gerais [CEX-109/04]Brazilian National Research Council [152068/2007-4]Research Foundation of the State of Sao Paulo [06/05920-7]CNPq [307890/2006-6, 304857/2006-8

Avaliação da pressão positiva expiratória final utilizando o aparelho fisioterápico Quake Evaluation of positive end expiratory pressure using a physiotherapy device called Quake

O objetivo deste estudo foi avaliar, em voluntários saudáveis, o valor médio da pressão positiva expiratória final (PEEP) na utilização do recurso fisioterápico Quake, relativamente novo no mercado. Participaram 62 indivíduos de ambos os sexos, entre 18 e 30 anos, que foram submetidos a: prova de função pulmonar; avaliação do pico de fluxo expiratório, da sensação subjetiva de esforço (escala de Borg) e da saturação de oxigênio; e à utilização do aparelho, acoplado a um manovacuômetro, para efetuar duas seqüências respiratórias, de 10 e 20 incursões por minuto, monitoradas por retroalimentação visual. Os dados foram tratados estatisticamente. Foi observada diferença significativa entre os valores das pressões geradas apenas na seqüência de 10 incursões por minuto (p=0,03). Na comparação das pressões entre as seqüências, os valores foram significativamente menores na de 10 incursões (29,42±8,04 cmH2O; p=0,03). Não foram encontradas correlações entre as pressões e as variáveis da espirometria, idade e pico de fluxo expiratório. Foi observada uma fraca correlação significativa antes (r=0,36; p=0,003) e depois (r=0,31; p=0,014) da seqüência de 20 incursões entre as pressões nessa seqüência e os escores de fadiga na escala de Borg, tendo o mesmo ocorido com a saturação de oxigênio. A PEEP gerada pelo Quake em indivíduos saudáveis varia de acordo com a frequência em incursões por minuto, sendo maior durante a seqüência mais rápida, que também gera maior cansaço.<br>The aim of this study was to assess the mean positive end expiratory pressure (PEEP) during use of the Quake, a relatively new device, in healthy volunteers. Participants were 62 subjects of both sexes aged 18 to 30 years old, who were submitted to: pulmonary function tests; expiratory peak flow evaluation; the Borg scale; assessment of oxygen saturation; and use of the device, coupled to a manometer, in two sequences, of 10 and 20 breaths per minute, with monitoring by visual feedback. Data were statistically analysed. Significant differences between pressures were found only at the 10-breath per minute sequences (p=0.03). When comparing pressures between the sequences, values were significantly lower in the 10-breath per minute sequence (29.42±8.04 cmH2O; p=0.03). No correlations were found between pressures and pulmonary function test measures, age, or expiratory peak flow. A weak, significant correlation was found between Borg scale scores and pressures before (r=0.36; p=0.003) and after (r=0.31; p=0.014) the 20-breath per minute sequence, the same occurring with oxygen saturation. In healthy volunteers, then, Quake PEEP values are higher during the quickest (20-breath per minute) sequence, which also requires more exeertion