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Micro-electrode array (MEA) electrophysiological signal analysis by descriptive stochastic tests of the probability density structure

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Research on biomedical engineering 2025年第2期41卷 1-13页

作者： Faria, Vinícius Naves Rezende Ramos, Marina Abadia Martinoia, Sérgio Destro-Filho, João-Batista Postgraduate Program in Electrical Engineering Universidade Federal de MG Uberlândia Brazil Postgraduate Program in Biomedical Sciences Universidade Federal de MG Uberlândia Brazil Division of Informatics Bioengineering Robotics and System Engineering Università Degli Studi Di Genova Genova Italy

Purpose: The primary objective of this study is to present, analyze, and quantitatively characterize the electrical signals obtained from neuronal cultures coupled to micro-electrode arrays (MEAs). Special attention is given to the temporal evolution of electrical activity across distinct geometric regions of the MEA devices. Methods: The proposed methodology involves signal acquisition, classical analysis based on spike and burst detection, and, critically, the characterization of the probability density structure of the signals. This is achieved through the quantification of Gaussianity—expressed as the percentage of segments non-Gaussian (PSNG)—and stationarity— expressed as the percentage of segments non-stationary (PSNE). Results: Initial analyses showed that first-order power spectral density quantifiers lacked the statistical robustness required to effectively describe the complex components of MEA signals. In contrast, PSNG and PSNE demonstrated strong potential in capturing the different stages of neuronal culture development. Cluster analysis further supported the discriminative capacity of these quantifiers. Conclusion: The phase corresponding to decreased neuronal activity and onset of cell death—a biologically critical stage—exhibited the strongest correlation among the studied variables. These results suggest a discernible biological organization and highlight the relevance of PSNG and PSNE as promising tools for assessing neuronal culture dynamics. © The Author(s), under exclusive licence to The Brazilian Society of biomedical engineering 2025.

关键词： Cell death

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Evaluation of Maternal and Fetal S-Values from Iodine Isotopes in Nuclear Medicine Using the Monte Carlo Method

SSRN

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SSRN 2025年

作者： Coelho, Nathalia B.M. Alves, Arthur de Souza Borges Zuchet Santos, Carla J. Neves, Lúcio P. Perini, Ana P. Belinato, Walmir Ferreira, José Rafael S. Santos, William S. Postgraduate Program in Biomedical Engineering Faculty of Electrical Engineering Federal University of Uberlândia Uberlândia Brazil Institute of Physics Federal University of Uberlândia Uberlândia Brazil Federal Institute of Bahia - IFBA BA Vitória da Conquista Brazil Department of Physics Federal University of Sergipe São Cristóvão Brazil Universidade Federal da Bahia Brazil

The use of radionuclides for therapeutic and diagnostic purposes is the primary function of nuclear medicine. Among these radionuclides, the iodine family stands out as isotopes that can serve various purposes, including brachytherapy, scintigraphy, and research. The internal dosimetry of these nuclides becomes even more important when considering high-risk groups such as pregnant patients, as it involves concerns for both the mother and the fetus. This study aims to use Monte Carlo simulations to calculate S-values for a set of target organs in both the pregnant woman and the fetus, considering different source organs in the mother and three iodine isotopes: 131I, 125I, and 123I. The results indicated that 131I, with the highest emission energy, presented a high dose deposition pattern in target organs farther from the source organs, while 125I, with the lowest energy, showed a localized dose absorption pattern in adjacent organs. The highest S-values (all in mGy/MBq.s) were obtained for the pregnant woman, with values of 5.8E-05 in the thyroid using 123I and 125I, and 3.7E-04 in the bladder using 131I. For fetal organs, the most irradiated were the brain and skull using 131I, with values of 6.3E-06 and 5.6E-06, respectively, while the lowest values were associated with the use of 125I in source organs distant from the target organ, with contributions as low as 1E-12 for the thyroid as a source. This work presents a qualitative and quantitative study of the internal dosimetry of a pregnant patient and her fetus, addressing variables such as radioactive isotope and source and target organs, serving as a reference for dosimetric calculations deemed necessary in clinical practices to minimize the dose received by this critical group. © 2025, The Authors. All rights reserved.

关键词： Nuclear medicine

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Multilocus sequence typing of Treponema pallidum in male patients with genital ulcers in a public sexually transmitted infections clinic: a new allele and almost complete macrolide resistance

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Anais Brasileiros de Dermatologia 2025年第3期100卷 569-573页

作者： Esteves, Leonardo Souza Grassi, Vera Mileide Trivellato Grassi, Liliane Trivellato Nicola, Maria Rita Castilhos Silva, Marcia Susana Nunes Rossetti, Maria Lucia Rosa Ramos, Mauro Cunha Laboratory of Molecular Biology Applied to Microbacteria Fundação Oswaldo Cruz RJ Rio de Janeiro Brazil Program in Cellular and Molecular Biology Applied to Health Sciences Universidade Luterana do Brasil RS Canoas Brazil Biomedical Engineering Universidade Luterana do Brasil RS Canoas Brazil Sanitary Dermatology Outpatient Unit Secretaria Estadual de Saúde RS Porto Alegre Brazil DNTech - Development of New Technologies LTDA Agência Estadual de Pesquisa Desenvolvimento e Inovação do Rio Grande do Sul / Financiadora de Estudos e Projetos RS Porto Alegre Brazil Postgraduate Program Faculdade de Biologia Celular e Molecular Aplicada à Saúde Universidade Luterana do Brasil RS Canoas Brazil

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Performance of atrial conduction velocity algorithms with error-prone clinical measurements for the identification of atrial fibrosis

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Computers in Biology and Medicine 2025年 191卷 110119-110119页

作者： Gharaviri, Ali Vigneswaran, Vinush Vickneson, Keeran Roney, Caroline Corrado, Cesare Coveney, Sam Maciunas, Kestutis Bodagh, Neil Klis, Magda Kotadia, Irum Sim, Iain Whitaker, John Bishop, Martin Niederer, Steven O'Neill, Mark Williams, Steven E. Centre for Cardiovascular Science The University of Edinburgh United Kingdom School of Biomedical Engineering and Imaging Sciences King's College London United Kingdom School of Engineering and Materials Science Queen Mary University of London United Kingdom National Heart & Lung Institute - Faculty of Medicine Imperial College London United Kingdom Heart Rhythm Research Brussels Postgraduate Program in Cardiac Electrophysiology and Pacing Vrije Universiteit Brussel Brussels Belgium Heart Rhythm Management Centre Universitair Ziekenhuis Brussel Brussels Belgium Brussels1050 Belgium

Introduction: Measuring conduction velocity, as a direct consequence of fibrosis, may provide a better method to localise fibrotic regions. This study aims to assess established cardiac conduction velocity calculation methods (Triangulation, Polynomial Surface Fitting, and Radial Basis Function) in identifying areas of conduction slowing caused by fibrosis, considering realistic measurement errors. Method: Using a human left atrium computational model, atrial activation was simulated. Each conduction velocity calculation method's performance was evaluated under uncertainties in mapping point density, local activation time assignment and electrode locations by comparing calculated conduction velocity to ground truth conduction velocity derived from high-resolution simulated atrial activation. Results: All methods agreed well with ground truth conduction velocity maps in noise-free, high-density sampling conditions. However, Triangulation and Polynomial Surface Fitting methods showed susceptibility to noise, exhibiting significant errors under moderate to high noise levels. Radial Basis Function method demonstrated greater robustness to noise and reduced sampling density. Fibrotic region identification accuracy was high under ideal conditions for all methods but declined with increasing noise, with the Radial Basis Function method maintaining superior performance. Conclusion: While all methods accurately estimate conduction velocity under ideal conditions, the Radial Basis Function method shows robustness to a realistic clinical noise, hence making it the most suitable to identify fibrotic regions. © 2025

关键词： Triangulation

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Evaluation of fluoride concentration in toothpastes with antimicrobial molecules commercialized in Brazil

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Research on biomedical engineering 2021年第1期37卷 9-14页

作者： Medeiros, Maria da Conceição de Araújo Valadas, Lídia Audrey Rocha Lotif, Mara Assef Leitão Bottenberg, Peter Marciano, Fernanda Roberta Biomedical Engineering Postgraduate Program Brazil University São Paulo Brazil Development and Technological Innovation in Medicines Postgraduate Program Federal University of Ceara Fortaleza Brazil Brussels Belgium

Purpose: This study aimed to analyze the fluoride concentrations in different dentifrices with antimicrobial and natural molecules marketed in Brazil. Thus, 12 dentifrices were selected to be analyzed for the concentration of total fluoride (TF), total soluble fluoride (TSF) and ionizable fluoride (IF). Methods: Two tubes of each brand were purchased at different locations. The samples were analyzed in duplicates using an ion-specific electrode and the concentrations were determined in μg F/g. Results: The TF of all calcium carbonate dentifrices showed averages below 1500 ppm F. Regarding TSF, only one toothpaste had an average above 1000 ppm F−, while the IF values were almost 500 ppm F. In the analysis of fluoride in dentifrices which present silica as abrasive, the TF presented averages below 1500 ppm F, while the TSF all presented averages close to 1000 ppm F−, and the IF values varied from close to 500 ppm to more than 1000 ppm F. In dentifrices whose formulation contained calcium carbonate associated with silica or other formulations such as sodium bicarbonate, the TF, TSF, and IF values were all above 1000 ppm F. Conclusion: The evaluated dentifrices generally showed TF concentrations lower than those declared on the packaging;however, the TSF content remained close to 1000 ppm F. It can be concluded that the analyzed dentifrices with antimicrobial molecules showed values close to those suggested regarding anti-caries effect. © 2020, Sociedade Brasileira de Engenharia Biomedica.

关键词： Calcium carbonate

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Possible solutions for oxygenation support in critically ill patients with COVID-19

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Research on biomedical engineering 2021年第2期37卷 389-402页

作者： de Souza, Daniel Baldoino de Oliveira Andrade, Adriano Milagre, Selma Terezinha Pereira, Adriano Alves Centre for Innovation and Technology Assessment in Health Postgraduate Program in Electrical and Biomedical Engineering Faculty of Electrical Engineering Federal University of Uberlândia Uberlândia Brazil

Purpose: Due to the large number of patients with respiratory deficiency during the COVID-19 pandemic, several governments and their respective health care services have been studying ways to complement the care provided by offering immediate solutions. In view of this, the aim of this study was to carry out a systematic review of the advantages and disadvantages of possible solutions in oxygenation support. Methods: This systematic review used the PRISMA-P methodology and sought to list alternatives in oxygenation support that are being applied and studied worldwide. A bibliographic search was conducted in the MEDLINE and Cochrane Central databases, using the keywords SARS-CoV-2, COVID19, or coronavirus;combined with extracorporeal membrane oxygenation (ECMO), mechanical ventilation, mechanical ventilation support, low-cost, anesthesia, anesthesia machine, and ventilation therapy. The records were also found in the gray literature. Results: The search found 85 publications of which 41 articles were considered after excluding duplicate articles, reading the title and summary, and reading the articles in full. The oxygenation supports identified in these publications were the following: ECMO, shared mechanical ventilator, fast or low-cost production equipment, high-flow nasal cannula (HFNC), non-invasive ventilation, and use of anesthesia equipment as a mechanical ventilator. Conclusion: This study demonstrated the importance of a trained clinical team in the application of technologies. The alternatives found for support oxygenation require a more robust clinical evaluation to demonstrate their efficacy and safety for the COVID-19 patient. © 2021, Sociedade Brasileira de Engenharia Biomedica.

关键词： Oxygenation

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Effect of exposure to a light-emitting diode (LED) on the physicochemical characteristics of natural latex biomembranes used to treat diabetic ulcers

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Research on biomedical engineering 2022年第3期38卷 901-911页

作者： Santana, Thamis Fernandes Oliveira, Rebeca Hannah de Melo dos Santos, Ludmila Evangelista Lima, Eunice Paloma Nascimento Faria, Sylvia de Sousa Fonseca, Marcos Augusto Moutinho da Silva, Jaqueline Rodrigues Tatmatsu-Rocha, José Carlos Gomes, Marília Miranda Forte Fleury Rosa, Mário Fabrício Fleury Rosa, Suélia de Siqueira Rodrigues Carneiro, Marcella Lemos Brettas Postgraduate Program in Biomedical Engineering University of Brasilia Federal District Brasilia Brazil Postgraduate Program in Materials Science and Engineering Federal University of Campina Grande Paraiba Campina Grande Brazil Department of Electrical Engineering University of Brasilia Federal District Brasilia Brazil Postgraduate Program in Biology Animal University of Brasilia Federal District Brasilia Brazil Medicine Faculty Physical Therapy Department Federal University of Ceara Ceara Fortaleza Brazil Postgraduate Technology and Health Program University of Brasília Federal District Brasília Brazil

Purpose: Natural latex biomembrane has shown high therapeutic potential for the treatment of diabetic ulcers when associated with phototherapy. In this study, physical and chemical alterations in the latex biomembranes were evaluated after exposure to light-emitting diode (LED) irradiation and after contact with NaCl solution. Methods: There were three experimental groups: natural latex biomembranes (1) in natura;(2) after 35 min of LED light irradiation;and (3) after immersion in NaCl 0.9 g% solution. The samples were analyzed by tensile strength test, thermogravimetry, contact angle wettability, and Fourier-transform infrared spectroscopy. Results: The biomembranes that were submitted to contact with NaCl aqueous solution or exposure to LED did not undergo impairment of mechanical resistance. The thermogravimetry analysis indicated that increasing temperature led to mass loss in all samples, referring to their decomposition temperatures. In the wettability test, biomembranes exposed to LED showed a significant reduction in the contact angle between 0 and 10 min, indicating an increase in hydrophilicity, suggesting water storage capacity. The Fourier-transform infrared spectrometry assay showed that there was a more significant reduction in vibration intensity after immersion in NaCl solution compared to untreated biomembranes. An increase in the intensity of the entire spectrum of biomembranes exposed to LED was observed in comparison with the other samples, which may be related to photodegradation caused by LED light irradiation. Conclusion: The biomembranes underwent significant changes in its chemical structure after being subjected to different types of exposure and maintained its elasticity and tensile strength properties, in addition to showing good water retention capacity after exposure to LED. Thus, it maintains many of its properties for application as a tissue-regenerating biomaterial, even when subjected to LED irradiation and a humid environment. © 20

关键词： Tissue regeneration

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Extracorporeal membrane oxygenation versus conventional therapy in patients with acute respiratory failure: systematic review with meta-analysis

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Research on biomedical engineering 2024年第3-4期40卷 835-849页

作者： de Souza, Daniel Baldoino Barreto, Cassiana Gabriela Lima Milagre, Selma Terezinha Pereira, Adriano Alves University Hospital of the Federal University of Santa Catarina Florianópolis Brazil Centre for Innovation and Technology Assessment in Health Faculty of Electrical Engineering Postgraduate Program in Electrical and Biomedical Engineering Federal University of Uberlândia Uberlândia Brazil

Background: Acute respiratory distress syndrome (ARDS) is a severe condition where lung alveoli fill with fluid, depriving organs of oxygen and risking death. Mechanical ventilation is conventional for oxygen therapy, but extracorporeal membrane oxygenation (ECMO) may be needed for refractory ARDS cases. This study aims to compare ECMO's impact on mortality and hospital stay versus conventional treatment for patients aged 12 or older with moderate or severe ARDS in intensive care units (ICUs). Methodology: Four independent reviewers followed the PRISMA-P method for the review. The key question used the PICOS tool. Databases searched included Cochrane Library, Bireme, MEDLINE, EMBASE, Web of Science, Scielo, LILACS, and grey literature to minimize publication bias. Selected papers were randomized controlled trials (RCTs) without language restrictions, meeting predefined inclusion and exclusion criteria. RoB-2 assessed bias risk, and GRADE evaluated evidence quality. Mortality was analyzed using a fixed-effect PETO method (odds ratio), and hospital stay was treated as a continuous variable using inverse variance and standardized mean difference (SMD). Results: We found 3,774 articles and selected 6 studies with 1,050 participants. Of these, 519 were allocated to the intervention group (ECMO) and 531 to the conventional treatment group (MV). The risk of bias for 3 studies was "some concerns," and 3 were "high risk of bias," mainly due to "deviations from intended/planned interventions" and "selection of reported outcomes." The primary outcomes for 30-day, 60-day, 90-day, and 180-day mortality showed odds ratios of 0.90 (95% CI: 0.66–1.21), 0.78 (95% CI: 0.50–1.21), 0.90 (95% CI: 0.66–1.21), and 0.62 (95% CI: 0.36–1.06) respectively, with low heterogeneity (I2 0.10). The secondary outcomes for a total length of stay and ICU stay showed standardized mean differences of 0.39 (95% CI: 0.13–0.65) and 0.33 (95% CI: 0.05–0.60) respectively, with substantial heterogeneity (I2

关键词： Risk assessment

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Control engineering investigation of the effects of proliferative diabetic retinopathy on the crystalline lens and ciliary muscle dynamic behavior

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Research on biomedical engineering 2023年第3期39卷 663-676页

作者： Oliveira, Rebeca Hannah de M. Silva, Mayla dos S. Nunes, Gustavo A. M. A. Faria, Rafael Mendes Santos, Kleriston Silva Rosa, Leandro L. F. Rosa, Mário F. F. Rosa, Suélia de S. R. F. Department of Biomedical Engineering Johns Hopkins University School of Medicine BaltimoreMD United States Postgraduate Program in Mechatronic Systems University of Brasília DF Brasilia Brazil Optometry Clinic GO Goiânia Brazil Biomedical Engineering Graduate Program University of Brasília DF Brasilia Brazil University of Brasilia – UnB DF Brasilia Brazil

Purpose: Proliferative diabetic retinopathy (PDR) affects more than 100 million adults worldwide and is one of the primary diseases leading to blindness and affecting the eye’s retina. Few papers mention its impact on the anterior segment of the eye. Methods: We present a novel bond graph model of the human eye calibrated with data from the literature to simulate the effects of retinopathy on lens behavior. Through mathematical representation in state space and transfer functions, we simulate the dynamic responses of the physiological and pathological systems. Results: The dynamic response to impulse inputs shows a distinct peak amplitude (0.01 difference) and transient time (0.0001 s) for PDR and Healthy systems at Region B (lens and ciliary muscle). Qualitative increase in ocular vasculature aggravation attenuates PDR dynamic response to unitary step input compared to Healthy (50% decay at 20 days of simulation) at Region B. Conclusions: The model suggests the potential impact of PDR on ciliary muscle behavior, which can have a clinical translation on diagnosis, follow-up, and treatment of the disease. It can be used for future studies on the effects of retinopathy on different ocular regions. © 2023, The Author(s), under exclusive licence to The Brazilian Society of biomedical engineering.

关键词： Eye protection

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HIFU thermal lesion difference between simulated human phantom and tissue-mimicking phantom 24

HIFU thermal lesion difference between simulated human phant...

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24th International Congress on Acoustics, ICA 2022

作者： Kim, Seong Chan Choi, Min Joo Jeju National University Interdisciplinary Postgraduate Program of Biomedical Engineering Korea Republic of Jeju National University School of Medicine Korea Republic of

Most HIFU procedures use the thermal effect of ultrasound, and information about temperature is directly related to the effect and side effects of the procedure. In the case of the human body, there are complex structures including bones around the target tissue to be irradiated with ultrasound. Thermal lesions in human tissue differ from thermal lesions in ideal conditions due to the standing waves generated by the target tissue and surrounding structures. If a high temperature rise is induced at a location other than the focal point of the HIFU, side effects of the procedure and patient safety may be threatened. In this study, two conditions were simulated, a tissue-mimicking phantom and a human body, in order to compare differences in thermal lesions. In the simulation results, the shape of the thermal lesion generated in the two conditions was not the same, and there was a difference in the location where the temperature was increased. © ICA *** rights reserved

关键词： HIFU Human phantom Thermal lesion Tissue mimicking phantom

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