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Publicações

Publicações por BIO

2021

Attention Based Deep Multiple Instance Learning Approach for Lung Cancer Prediction using Histopathological Images

Autores
Moranguinho, J; Pereira, T; Ramos, B; Morgado, J; Costa, JL; Oliveira, HP;

Publicação
2021 43RD ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY (EMBC)

Abstract
Deep Neural Networks using histopathological images as an input currently embody one of the gold standards in automated lung cancer diagnostic solutions, with Deep Convolutional Neural Networks achieving the state of the art values for tissue type classification. One of the main reasons for such results is the increasing availability of voluminous amounts of data, acquired through the efforts employed by extensive projects like The Cancer Genome Atlas. Nonetheless, whole slide images remain weakly annotated, as most common pathologist annotations refer to the entirety of the image and not to individual regions of interest in the patient's tissue sample. Recent works have demonstrated Multiple Instance Learning as a successful approach in classification tasks entangled with this lack of annotation, by representing images as a bag of instances where a single label is available for the whole bag. Thus, we propose a bag/embedding-level lung tissue type classifier using Multiple Instance Learning, where the automated inspection of lung biopsy whole slide images determines the presence of cancer in a given patient. Furthermore, we use a post-model interpretability algorithm to validate our model's predictions and highlight the regions of interest for such predictions.

2020

A vast resource of allelic expression data spanning human tissues

Autores
Castel S.E.; Aguet F.; Aguet F.; Aguet F.; Mohammadi P.; Mohammadi P.; Anand S.; Anand S.; Ardlie K.G.; Ardlie K.G.; Gabriel S.; Getz G.A.; Graubert A.; Graubert A.; Hadley K.; Hadley K.; Handsaker R.E.; Handsaker R.E.; Huang K.H.; Kashin S.; Kashin S.; Li X.; MacArthur D.G.; Meier S.R.; Meier S.R.; Nedzel J.L.; Nedzel J.L.; Nguyen D.T.; Segrè A.V.; Todres E.; Todres E.; Balliu B.; Barbeira A.N.; Battle A.; Bonazzola R.; Brown A.; Brown C.D.; Castel S.E.; Conrad D.F.; Cotter D.J.; Cox N.; Das S.; De Goede O.M.; Dermitzakis E.T.; Einson J.; Engelhardt B.E.; Eskin E.; Eulalio T.Y.; Ferraro N.M.; Flynn E.D.; Fresard L.; Gamazon E.R.; Garrido-Martín D.; Gay N.R.; Gloudemans M.J.; Guigó R.; Hame A.R.; He Y.; Hoffman P.J.; Hormozdiari F.; Hou L.; Huang K.H.; Im H.K.; Jo B.; Kasela S.; Kellis M.; Kim-Hellmuth S.; Kwong A.; Lappalainen T.; Li X.; Li X.; Liang Y.; Mangul S.; Montgomery S.B.; Muñoz-Aguirre M.; Nachun D.C.; Nguyen D.T.; Nobel A.B.; Oliva M.; Park Y.S.; Park Y.; Parsana P.; Rao A.S.; Reverter F.; Rouhana J.M.; Sabatti C.; Saha A.; Segrè A.V.; Skol A.D.; Stephens M.; Stranger B.E.; Strober B.J.; Teran N.A.; Viñuela A.; Wang G.; Wen X.; Wright F.; Wucher V.; Zou Y.; Ferreira P.G.;

Publicação
Genome Biology

Abstract
Allele expression (AE) analysis robustly measures cis-regulatory effects. Here, we present and demonstrate the utility of a vast AE resource generated from the GTEx v8 release, containing 15,253 samples spanning 54 human tissues for a total of 431 million measurements of AE at the SNP level and 153 million measurements at the haplotype level. In addition, we develop an extension of our tool phASER that allows effect sizes of cis-regulatory variants to be estimated using haplotype-level AE data. This AE resource is the largest to date, and we are able to make haplotype-level data publicly available. We anticipate that the availability of this resource will enable future studies of regulatory variation across human tissues.

2020

Impact of Different Stimuli on User Stress During a Virtual Firefighting Training Exercise

Autores
Narciso, D; Melo, M; Rodrigues, S; Cunha, JPS; Bessa, M;

Publicação
2020 IEEE 20TH INTERNATIONAL CONFERENCE ON BIOINFORMATICS AND BIOENGINEERING (BIBE 2020)

Abstract
Training firefighters using Virtual Reality (VR) technology brings several benefits over traditional training methods including the reduction of costs and risks. The ability of causing the same level of stress as a real situation so that firefighters can learn how to deal with stress was investigated. An experiment aiming to study the influence that additional stimuli (heat, weight, smell and using personal protective equipment-PPE) have on user's stress level while performing a Virtual Environment (VE) designed to train firefighters was developed. Participants' stress and Heart Rate Variability (HRV) were obtained from electrocardiograms recorded during the experiment. The results suggest that wearing the PPE has the largest impact on user's stress level. The results also showed that HRV was able to evidence differences between two phases of the experiment, which suggests that it can be used to monitor users' quantified reaction to VEs.

2020

Interpretable Biometrics: Should We Rethink How Presentation Attack Detection is Evaluated?

Autores
Sequeira, AF; Silva, W; Pinto, JR; Goncalves, T; Cardoso, JS;

Publicação
2020 8TH INTERNATIONAL WORKSHOP ON BIOMETRICS AND FORENSICS (IWBF 2020)

Abstract
Presentation attack detection (PAD) methods are commonly evaluated using metrics based on the predicted labels. This is a limitation, especially for more elusive methods based on deep learning which can freely learn the most suitable features. Though often being more accurate, these models operate as complex black boxes which makes the inner processes that sustain their predictions still baffling. Interpretability tools are now being used to delve deeper into the operation of machine learning methods, especially artificial networks, to better understand how they reach their decisions. In this paper, we make a case for the integration of interpretability tools in the evaluation of PAD. A simple model for face PAD, based on convolutional neural networks, was implemented and evaluated using both traditional metrics (APCER, BPCER and EER) and interpretability tools (Grad-CAM), using data from the ROSE Youtu video collection. The results show that interpretability tools can capture more completely the intricate behavior of the implemented model, and enable the identification of certain properties that should be verified by a PAD method that is robust, coherent, meaningful, and can adequately generalize to unseen data and attacks. One can conclude that, with further efforts devoted towards higher objectivity in interpretability, this can be the key to obtain deeper and more thorough PAD performance evaluation setups.

2020

Extracting neuronal activity signals from microscopy recordings of contractile tissue: a cell tracking approach using B-spline Explicit Active Surfaces (BEAS)

Autores
Kazwiny, Y; Pedroso, JM; Zhang, Z; Boesmans, W; D'hooge, J; Vanden Berghe, P;

Publicação

Abstract
Ca 2+ imaging is a widely used microscopy technique to simultaneously study cellular activity in multiple cells. The desired information consists of cell-specific time series of pixel intensity values, in which the fluorescence intensity represents cellular activity. For static scenes, cellular signal extraction is straightforward, however multiple analysis challenges are present in recordings of contractile tissues, like those of the enteric nervous system (ENS). This layer of critical neurons, embedded within the muscle layers of the gut wall, shows optical overlap between neighboring neurons, intensity changes due to cell activity, and constant movement. These challenges reduce the applicability of classical segmentation techniques and traditional stack alignment and regions-of-interest (ROIs) selection workflows. Therefore, a signal extraction method capable of dealing with moving cells and is insensitive to large intensity changes in consecutive frames is needed. Here we propose a b-spline active contour method to delineate and track neuronal cell bodies based on local and global energy terms. We develop both a single as well as a double-contour approach. The latter takes advantage of the appearance of GCaMP expressing cells, and tracks the nucleus’ boundaries together with the cytoplasmic contour, providing a stable delineation of neighboring, overlapping cells despite movement and intensity changes. The tracked contours can also serve as landmarks to relocate additional and manually-selected ROIs. This improves the total yield of efficacious cell tracking and allows signal extraction from other cell compartments like neuronal processes. Compared to manual delineation and other segmentation methods, the proposed method can track cells during large tissue deformations and high-intensity changes such as during neuronal firing events, while preserving the shape of the extracted Ca 2+ signal. The analysis package represents a significant improvement to available Ca 2+ imaging analysis workflows for ENS recordings and other systems where movement challenges traditional Ca 2+ signal extraction workflows.

2020

Discrimination of Benign and Malignant Lesions in Canine Mammary Tissue Samples Using Raman Spectroscopy: A Pilot Study

Autores
Dantas, D; Soares, L; Novais, S; Vilarinho, R; Moreira, JA; Silva, S; Frazao, O; Oliveira, T; Leal, N; Faisca, P; Reis, J;

Publicação
ANIMALS

Abstract
Simple Summary Neoplastic diseases are among the leading causes of death worldwide and constitute the main health problem in both human and veterinary medicine, particularly as the occurrence of the disease continues to increase. Comparative oncology is a quickly expanding field that examines both cancer risk and tumor development across species. Characterized by interdisciplinary collaboration, its goal is the improvement of both human and animal health. Canine neoplastic disease occurs spontaneously and has comparable clinical presentation and pathophysiology to corresponding human cancers. Since the nature of the disease is spontaneous, the complex interactions between tumor cells, tissues and the immune system can be better studied. Such relations are otherwise difficult to study in other experimental animal models. Raman spectroscopy has proved to be a suitable technique to detect and study breast microcalcifications. Raman spectroscopy is a specific and sensitive tool for identifying biomarkers of oncologic disease and also shows further potential in differentiating malignant and benign tumors, and these tumors from healthy tissue. Breast cancer is a health problem that affects individual life quality and the family system. It is the most frequent type of cancer in women, but men are also affected. As an integrative approach, comparative oncology offers an opportunity to learn more about natural cancers in different species. Methods based on Raman spectroscopy have shown significant potential in the study of the human breast through the fingerprinting of biological tissue, which provides valuable information that can be used to identify, characterize and discriminate structures in breast tissue, in both healthy and carcinogenic environments. One of the most important applications of Raman spectroscopy in medical diagnosis is the characterization of microcalcifications, which are highly important diagnostic indicators of breast tissue diseases. Raman spectroscopy has been used to analyze the chemical composition of microcalcifications. These occur in benign and malignant lesions in the human breast, and Raman helps to discriminate microcalcifications as type I and type II according to their composition. This paper demonstrates the recent progress in understanding how this vibrational technique can discriminate through the fingerprint regions of lesions in unstained histology sections from canine mammary glands.

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