Entropy Analysis of Univariate Biomedical Signals:Review and Comparison of Methods

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Guest Editorial Special Issue on Cardiovascular System Monitoring and Therapy: Innovative Technologies and Internet of Things

The papers in this special section focus on cardiovascular system monitoring and therapy. The number of devices for the measurement and interpretation of biological systems that describe performance of the cardiovascular system is growing. Among others, this is due to the improvement of circuit and system design that renders the devices wearable and easy to use. Moreover, internetworking enables these devices to exchange data. Their true impact on patient care is highly dependent on the quality and relevancy of the data acquired. The design of circuits and systems to answer the growing demand and the necessity to have portable and connected devices lead to a focus on designing ultra-low power apparatus, mixed-signal devices, using nanoscale electronics. Microelectronic issues are therefore at the heart of the demand. All this requires inter-disciplinary collaborations between scientists, engineers, medical researchers, and practitioners. The interconnection of these embedded devices, known as Internet of Things, is expected to usher in the medical field, among others to study the cardiovascular system of patients. Data processing and storage will also take place in the healthcare information technology. Furthermore, key issues such as data security and privacy will be determinants of the utility of these systems and impact in healthcare monitoring and management. This special issue aimed to provide a forum for both established experts and newinvestigators to share their developments, knowledge, and insights for the further design of circuits and systems aiming at being integrated in sensors to monitor or treat the cardiovascular system

Fuzzy Entropy Metrics for the Analysis of Biomedical Signals: Assessment and Comparison

Fuzzy entropy (FuzEn) was introduced to alleviate limitations associated with sample entropy (SampEn) in the analysis of physiological signals. Over the past decade, FuzEn-based methods have been widely used in various real-world biomedical applications. Several fuzzy membership functions (MFs), including triangular, trapezoidal, Z-shaped, bell-shaped, Gaussian, constant-Gaussian, and exponential functions have been employed in FuzEn. However, these FuzEn-based metrics have not been systematically compared yet. Since the threshold value r used in FuzEn is not directly comparable across different MFs, we here propose to apply a defuzzication approach using a surrogate parameter called \u27center of gravity\u27 to re-enable a fair and direct comparison. To evaluate these MFs, we analyze several synthetic and three clinical datasets. FuzEn using the triangular, trapezoidal, and Z-shaped MFs may lead to undened entropy values for short signals, thus providing a very limited advantage over SampEn. When dealing with an equal value of the center of gravity, the Gaussian MF, as the fastest algorithm, results in the highest Hedges\u27 g effect size for long signals. Our results also indicate that the FuzEn based on exponential MF of order four better distinguishes short white, pink, and brown noises, and yields more signicant differences for the short real signals based on Hedges\u27 g effect size. The triangular, trapezoidal, and Z-shaped MFs are not recommended for short signals. We propose to use FuzEn with Gaussian and exponential MF of order four for characterization of short (around 50400 sample points) and long data (longer than 500 sample points), respectively. We expect FuzEn with Gaussian and exponential MF as well as the concept of defuzzication to play prominent roles in the irregularity analysis of biomedical signals. The MATLAB codes for the FuzEn with different MFs are available at https://github.com/HamedAzami/FuzzyEntropy_Matlab

Episode H5N8 d'influenza aviaire en France en 2016-2017 : quel rôle pour la faune sauvage ?

L'influenza aviaire (IA) est une menace permanente, qui arrive parfois en Europe par le biais des oiseaux migrateurs. Un dispositif de surveillance est en place en permanence pour surveiller les mortalités dans l'avifaune, et particulièrement celles des oiseaux d'eau migrateurs. En octobre 2016, un épisode d'IA H5N8 qui était surveillé depuis sa survenue en République de Touva (Fédération de Russie, avril 2016) s'est déclaré en Europe. Il a entraîné des pertes conséquentes dans certaines populations d'oiseaux sauvages en Europe, ainsi que dans des filières avicoles. La situation en France s'est révélée paradoxale : l'atteinte a été majeure dans la filière avicole de canards gras du Sud- Ouest, mais les cas dans la faune sauvage sont restés peu nombreux et circonscrits. Ce n'est pas faute d'avoir renforcé la surveillance, soit événementielle (analyse des oiseaux trouvés morts) soit active autour des foyers domestiques. Plus de 800 cadavres d'oiseaux sauvages ont été analysés, dont beaucoup d'anatidés, 90 ont été détectés infectés regroupés en 55 cas dans l'avifaune libre et captive, et dix sites stratégiques ont fait l'objet d'une recherche intensifiée des cadavres et n'ont permis de trouver aucun cas positif supplémentaire. Plus de 300 oiseaux commensaux des élevages domestiques foyers ont été analysés et se sont tous révélés négatifs. Les performances du système de surveillance ne semblent pas pouvoir être mises en cause, et il apparaît donc qu'il y a bien eu des différences de circulation du virus par rapport à nos voisins d'outre-Rhin, mal expliquées à ce stade mais la situation en France est similaire à celle observée en Italie et en Espagne cet hiver, et correspond assez bien à l'épisode H5N8 qui avait circulé en Europe fin 2014/début 2015, sans toucher la France. (Résumé d'auteur

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Color Texture Analysis: A Survey

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Multivariate refined composite multiscale entropy analysis

International audienceMultiscale entropy (MSE) has become a prevailing method to quantify signals complexity. MSE relies on sample entropy. However, MSE may yield imprecise complexity estimation at large scales, because sample entropy does not give precise estimation of entropy when short signals are processed. A refined composite multiscale entropy (RCMSE) has therefore recently been proposed. Nevertheless, RCMSE is for univariate signals only. The simultaneous analysis of multi-channel (multivariate) data often over-performs studies based on univariate signals. We therefore introduce an extension of RCMSE to multivariate data. Applications of multivariate RCMSE to simulated processes reveal its better performances over the standard multivariate MSE