DSpace Collection:http://hdl.handle.net/11422/852024-03-29T06:28:30Z2024-03-29T06:28:30ZDesenvolvimento de um sistema de medição em tempo real, por espectroscopia de bioimpedância, capaz de determinar a concentração celularSilva, Marcos Antonio Salvino dahttp://hdl.handle.net/11422/214992023-12-21T03:02:07Z2020-06-01T00:00:00ZTitle: Desenvolvimento de um sistema de medição em tempo real, por espectroscopia de bioimpedância, capaz de determinar a concentração celular
Author(s)/Inventor(s): Silva, Marcos Antonio Salvino da
Advisor: Souza, Marcio Nogueira de
Abstract: This work developed an alternative biomass measurement system applied for real-time monitoring (online) of bioprocesses, through bioimpedance spectroscopy, using the BIS-STEP technique. The construction of this work was carried out in two stages: the first, to test the feasibility of applying this bioprocess monitoring technique, the experiments were carried out with the commercial yeast Saccharomyces cerevisiae. In this step, use a linear regression multivariate (LRM) to estimate the total number of total and viable cells, using bioimpedance parameters. The second step, in the interest of Farmanguinhos/Fiocruz, to extrapolate this technique to bacteria Bacillus thuringiensis var. israelensis (Bti). The latter (Bti) presented greater difficulty in the direct application of LRM commonly used in dielectric spectroscopy or bioimpedance techniques. A solution found, using respiratory parameters - oxygen uptake rate (OUR), shows the most comprehensive ones and can also be applied to the data obtained from the first experiments. The statiscal results were satisfactory for both microorganisms with an average Pearson correlation coefficient (r) above 0.9 and the Bland-Altman model evaluated the agreement between analytical and bioimpedance methods.
Publisher: Universidade Federal do Rio de Janeiro
Type: Tese2020-06-01T00:00:00ZComparação entre os algoritmos de análise de componentes Independentes e filtragem adaptativa para redução de artefato de piscada de olho em sinais de eletroencefalogramaLopes, Marcelle Guedes de Medeiros.http://hdl.handle.net/11422/214982023-12-21T03:02:07Z2020-10-01T00:00:00ZTitle: Comparação entre os algoritmos de análise de componentes Independentes e filtragem adaptativa para redução de artefato de piscada de olho em sinais de eletroencefalograma
Author(s)/Inventor(s): Lopes, Marcelle Guedes de Medeiros.
Advisor: Cagy, Mauricio
Abstract: Although the electro-oculogram (EOG) artifact is associated with the inherent
human action of blinking, it contaminates and distorts electroencephalogram (EEG)
waveforms, impairing the control of Brain-Machine Interfaces (BMI) based on cortical
activity. EEGLAB is a widely used toolbox for EOG attenuation in EEG, and has
classical techniques for this purpose like the Infomax and SOBI (Second-Order Blind
Identification) approaches of the Independent Component Analysis (ICA) method.
Despite the wide use of ICA in EOG removal for MCI applications, this technique has
difficulty in dealing with bidirectional contamination of the data. In order to mitigate
this characteristic of ICA, its variations Wavelet and Adaptive Filtering were evaluated
as pre-processing alternatives for MCI. The results showed that the tested methods
performed well in reducing EOG by keeping the retrieved EEG as close as possible to
the pure EEG signal. However, Adaptive Filtering has shown a slightly superior
performance in the analysis of the mean squared error-correlation pair.
Publisher: Universidade Federal do Rio de Janeiro
Type: Dissertação2020-10-01T00:00:00ZObtenção e caracterização de microbolhas com cápsulas de policaprolactona em ultrassom visando aplicações biomédicasMatheo, Lucas Lobiancohttp://hdl.handle.net/11422/214972023-12-21T03:02:07Z2020-08-01T00:00:00ZTitle: Obtenção e caracterização de microbolhas com cápsulas de policaprolactona em ultrassom visando aplicações biomédicas
Author(s)/Inventor(s): Matheo, Lucas Lobianco
Advisor: Pereira, Wagner Coelho de Albuquerque
Abstract: The objective of this work is to assess two polycaprolactone (PCL) porous capsules of
different molecular masses applied as ultrasound contrast agents (UCAs). The compared
features are capsule composition, stability, compressibility, ultrasonic cavitation, and
ultrasonic backscattering. The acoustic response of porous UCAs produced with two
molecular masses, 10,000 and 45,000 mg/mol of PCL capsules, is compared for the first time,
by evaluating the backscatter signals, the temporal stability, and the response to increasing
acoustic pressure intensities. The variation in molecular weight resulted in small variations in
the elastic module, in which PCL45 had a more elastomeric behavior than PCL10. Porous
PCL10 and PCL45 UCAs presented greater stability than phospholipid UCAs and thinner
capsule thickness than polymeric ones (16 to 26 nm). UCAs with PCL45 proved to be superior
to those with PCL10, since they showed greater backscattering in a variety of frequencies, as
well as greater response to diferente acoustic pressures allowed in clinical use of UCAs. PCL
is than considered a candidate for UCAs capsules in the polymer category. Both PCL capsules
have potential for biomedical applications, either for contrast ultrasound as well as for HIFU
treatments. In the latter, there are two possible uses, raise image contrast of a specific tissue
using ultrasound, and ablate the area using higher intensity. Also, PCL is compatible with a
wide variety of other polymers and can be copolymerized with other monomers, which
expands its possibilities for future applications.
Publisher: Universidade Federal do Rio de Janeiro
Type: Tese2020-08-01T00:00:00ZAvaliação de parâmetros de dados para construção de modelo classificador de tropismo de HIV-1Rodrigues, José Fernando dos Anjos.http://hdl.handle.net/11422/214962023-12-21T03:02:07Z2020-12-01T00:00:00ZTitle: Avaliação de parâmetros de dados para construção de modelo classificador de tropismo de HIV-1
Author(s)/Inventor(s): Rodrigues, José Fernando dos Anjos.
Advisor: Nobre, Flavio Fonseca
Abstract: AIDS is a disease of worldwide importance, caused by the HIV-1 virus. Of the
several existing subtypes, the most prevalent are the B and C subtypes. Although it has no
cure, several drugs have been developed over time to reduce its spread in the body. For
example, Maraviroque® administration requires determining that the virus has tropism by
the CCR5 receptor. There are highly accurate phenotypic tests, but they are very expensive
and not agile for use in clinical routine. As an alternative, artificial intelligence models were
developed to determine tropism by observing the sequence of 35 amino acids from gp120
region V3 of the virus. The models face difficulties in classifying correctly non-R5 tropism
virus. In this work, we evaluated automatic variable selection and data balancing steps for
classifiers performance. We used the random forest algorithm to develop separately trained
models with 1,622 sequences of subtype B and 560 sequences of subtype C. The models
were compared with the already established geno2pheno and T-CUP 2.0 classifiers. For
subtype B, the AUC of all models presented values close to 0.95 and presented performance
parity with the established predictors. For subtype C, the models presented AUC variants,
but with higher performance than the established classifiers. The models presented positions
that, despite having little variability, proved to be particularly important for the model. It
was concluded that data balancing did not bring improvements and the selection of variables
is a desirable step, but it should be performed considering previous information obtained
empirically.
Publisher: Universidade Federal do Rio de Janeiro
Type: Dissertação2020-12-01T00:00:00Z