Development of an optrode for characterization of tissue optical properties at the neural tissue-electrode interface

Thesis (M.Sc.Eng.)The use of implantable neural probes has become common, both for stimulation and recording, and their applications range from chronic pain treatment to implementation of brain machine interfaces (BMI). Studies have shown that signal quality of implanted electrodes decays over time mainly due to the immune response. Characterization of the tissue-electrode interface is critical for better understanding of the physiological dynamics and potential performance improvement of the electrode itself and its task. This work describes the fabrication of an implantable electrode with optical measurement capabilities for providing means to characterize the tissue-electrode interface using optical spectroscopy. The electrode has a set of waveguides embedded in its shanks, which are used to inject white light into tissue and then collect the light reflected from the tissue surrounding the shanks. The collected light was analyzed with a spectrometer and the spectra processed to detect changes in optical properties, information that allows to track physiological changes. It is believed that the immune response can be correlated to changes in scattering as more cells are recruited to the injury site. The increased cell density in local injury/implantation sites increases the amount of scattering due to the increased number of cell nuclei and membranes that light encounters in its path. Investigation of scattering and absorption coefficients in such interface and their change over time can provide useful data for modeling and determining physiological parameters like blood oxygenation while the actual shape of the acquired spectra might highlight particular phenomena that can be indicative of scaring process or hemorrhaging. Validation of this system was done using optical phantoms based on polystyrene spheres and solutions with various concentrations of fat emulsion, which yielded scattering coefficients similar to those of brain tissue. Results suggest that the developed optrodes are able to detect differences between samples with different scattering coefficients. Improvements of fabrication process are discussed based on experimental results and future work includes attempting to perform fluorescence measurements of voltage reporters for optogenetic applications. The ultimate goal of this project was to create a novel device that is capable of satisfying the unmet need of tissue characterization at the implanted electrode interface as well as a tool for the optogenetics field suitable for greater depths than those a microscope can achieve

Seeing and hearing egocentric actions: how much can we learn?

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Our interaction with the world is an inherently multi-modal experience. However, the understanding of human-to-object interactions has historically been addressed focusing on a single modality. In particular, a limited number of works have considered to integrate the visual and audio modalities for this purpose. In this work, we propose a multimodal approach for egocentric action recognition in a kitchen environment that relies on audio and visual information. Our model combines a sparse temporal sampling strategy with a late fusion of audio, spatial,and temporal streams. Experimental results on the EPIC-Kitchens dataset show that multimodal integration leads to better performance than unimodal approaches. In particular, we achieved a5.18%improvement over the state of the art on verb classification.Peer ReviewedPostprint (author's final draft

Comparative metabolomic study of transgenic versus conventional soybean using capillary electrophoresis–time-of-flight mass spectrometry

In this work, capillary electrophoresis–time-of-flight mass spectrometry (CE–TOF-MS) is proposed to identify and quantify the main metabolites found in transgenic soybean and its corresponding non-transgenic parental line both grown under identical conditions. The procedure includes optimization of metabolites extraction, separation by CE, on-line electrospray-TOF-MS analysis and data evaluation. A large number of extraction procedures and background electrolytes are tested in order to obtain a highly reproducible and sensitive analytical methodology. Using this approach, a large number of metabolites were tentatively identified based on the high mass accuracy provided by TOF-MS analyzer, together with the isotopic pattern and expected electrophoretic mobility of these compounds. In general, the same metabolites and in similar amounts were found in the conventional and transgenic variety. However, significant differences were also observed in some specific cases when the conventional variety was compared with its corresponding transgenic line. The selection of these metabolites as possible biomarkers of transgenic soybean is discussed, although a larger number of samples need to be analyzed in order to validate this point. It is concluded that metabolomic procedures based on CE-MS can open new perspectives in the study of transgenic foods in order to corroborate (or not) the equivalence with their conventional counterparts.Peer reviewe

Metaheuristic approaches for optimal broadcasting design in metropolitan MANETs

11th International Conference on Computer Aided Systems Theory. Las Palmas de Gran Canaria, Spain, February 12-16, 2007Mobile Ad-hoc Networks (MANETs) are composed of a set of communicating devices which are able to spontaneously interconnect without any pre-existing infrastructure. In such scenario, broadcasting becomes an operation of tremendous importance for the own existence and operation of the network. Optimizing a broadcasting strategy in MANETs is a multiobjective problem accounting for three goals: reaching as many stations as possible, minimizing the network utilization, and reducing the duration of the operation itself. This research, which has been developed within the OPLINK project (http://oplink.lcc.uma.es), faces a wide study about this problem in metropolitan MANETs with up to seven different advanced multiobjective metaheuristics. They all compute Pareto fronts of solutions which empower a human designer with the ability of choosing the preferred configuration for the network. The quality of these fronts is evaluated by using the hypervolume metric. The obtained results show that the SPEA2 algorithm is the most accurate metaheuristic for solving the broadcasting problem.Publicad

Impacto de una intervención didáctica basada en el uso de un exergame en la activación del área motora suplementaria durante procesos de coordinación motora: un estudio piloto en primaria

Our study investigated the effect of an exergaming didactic intervention in Physical Education (PE) on brain functioning associated with motor coordination. Five students formed the control group (received traditional didactic intervention) and four made up the experimental group (received exergaming didactic intervention). Functional near-infrared spectroscopy (fNIRS) measures were acquired at two time points (before and after intervention) by a 64-channel NIRScout system covering the supplementary motor area (SMA) while performing a bimanual digital flexion-extension coordination task. The results showed a more efficient activity pattern for the group that performed the gamified exergaming intervention than for the control group (traditional didactic intervention). In conclusion, our study reports neurofunctional evidence for effects of exergames on motor coordination.Este estudio busca analizar el efecto de una intervención educativa, basada en el uso de un exergame, sobre la actividad cerebral relacionada con procesos de coordinación motora. Cinco alumnos formaron parte del grupo control (fueron los que recibieron la intervención didáctica tradicional) y cuatro alumnos formaron parte del grupo experimental (recibieron la intervención educativa basada en el uso del exergame). Las medidas de espectroscopía funcional de infrarrojo cercano (fNIRS) se recogieron en dos momentos diferenciados (antes –medida PRE– y después –medida POST– de la intervención) con un sistema NIRScout de 64 canales, cubriendo el área motora suplementaria (SMA) durante la realización de una tarea de coordinación bimanual de flexión-extensión digital. Los resultados mostraron que parece existir un patrón de actividad más eficiente en el grupo que realizó la intervención de exergaming gamificada en comparación con el grupo que realizó la intervención didáctica tradicional. En conclusión, nuestro estudio muestra evidencia neurofuncional sobre los efectos de los exergames en la coordinación motora

Use of the polymerase-chain reaction (PCR) for early evaluation of etiological treatment in young adults chronically infected with Trypanosoma cruzi

Fourteen patients (age limits: 18-30) chronically infected with Trypanosoma cruzi and presenting positive blood PCR reactions, were submitted to etiological treatment with benznidazole, in Salta, Argentina. A control group of five patients of the same age and positive by PCR did not receive treatment. Post-treatment follow-up was performed with PCR and conventional serology. PCR became negative in 12/14 (85.7%) of the treated patients after six months follow up, compared to 1/5 (20%) in the control group (p = 0.01). All patients remained serologically positive after treatment.The reduction of PCR signals of infection after treatment may become an early evidence of cure in chronically infected young adult patients.Fil: Lacunza, Carlos Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Sánchez Negrette, Olga. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Mora, Maria Celia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Uncos, Delfor Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Segura, Maria Asuncion. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: del Castillo, Nestor Sigfrido. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garayzabal, María Isabel. Universidad Nacional de Salta; ArgentinaFil: Basombrio, Miguel Angel Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; Argentin

A phylogenomic approach reveals a low somatic mutation rate in a long-lived plant.

Somatic mutations can have important effects on the life history, ecology, and evolution of plants, but the rate at which they accumulate is poorly understood and difficult to measure directly. Here, we develop a method to measure somatic mutations in individual plants and use it to estimate the somatic mutation rate in a large, long-lived, phenotypically mosaic Eucalyptus melliodora tree. Despite being 100 times larger than Arabidopsis, this tree has a per-generation mutation rate only ten times greater, which suggests that this species may have evolved mechanisms to reduce the mutation rate per unit of growth. This adds to a growing body of evidence that illuminates the correlated evolutionary shifts in mutation rate and life history in plants