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[Background] bstructive failure of implanted shunts is the most common complication in the treatment of hydrocephalus. Biological material and debris accumulate in the inner walls of the valve and catheters block the normal flow of the drained cerebrospinal fluid causing severe symptoms with high morbidity and mortality. Unfortunately, at present, there is no effective preventive protocol or cleaning procedure available., [Objective] To assess whether externally applied, focused ultrasound beams can be used to resuspend deposits accumulated in brain shunts safely., [Methods] A computational model of an implanted brain shunt was implemented to test the initial design parameters of a system comprising several ultrasound transducers. Under laboratory conditions, configurations with 3 and 4 transducers were arranged in a triangle and square pattern with their radiation axis directed towards a target model of the device, 2 catheters and a brain shunt filled with water and deposited graphite powder. The ultrasound beams were then concentrated on the device across a head model., [Results] The computational model revealed that by using only 3 transducers, the acoustic field intensity on the valve was approximately twice that on the brain surface suggesting that acoustic cavitation could be selectively achieved. Resuspension of graphite deposits inside the catheters and the valve were then physically demonstrated and video-recorded with no temperature increase., [Conclusion] The technology presented here has the potential to be used routinely as a noninvasive, preventive cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.

Las cámaras de vídeo pueden ser empleadas como sensores para la monitorización sin contacto en tiempo real, aplicando sobre una secuencia de fotogramas distintos algoritmos de seguimiento y extracción de bioseñales. Las características de la cámara, como la resolución, la tasa de muestreo o las bandas espectrales de la luz susceptibles de captar, son determinantes en el rendimiento de los algoritmos. Este estudio pretende ser una prueba de concepto consistente en un vehículo aéreo no tripulado con cámara RGB integrada, cuyas imágenes captadas son procesadas por dos algoritmos, uno de detección de personas (YOLOv3) basado en redes neuronales y otro de medida de tasa cardiaca (Heartbeat) basado en fotopletismografía remota. Las pruebas funcionales llevadas a cabo para validar el montaje, la detección y la medida de tasa cardiaca realizada por el prototipo muestran que la detección de personas sin contacto en tiempo real puede llevarse a cabo bajo las condiciones, dispositivos y algoritmos expuestos, pero la medida de la tasa cardiaca se ve afectada por la inestabilidad de la transmisión de fotogramas en tiempo real.

This contribution presents a two-channel inexpensive arbitrary waveform neurostimulator based on a Raspberry Pi microcomputer platform and a Howland voltage-to-current converter. The system has been designed to enable the delivery of common stimulation strategies used in visual prosthesis research.

[Objective] To conduct a proof-of-concept study of the detection of two synthetic models of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using polarimetric imaging., [Approach] Two SARS-CoV-2 models were prepared as engineered lentiviruses pseudotyped with the G protein of the vesicular stomatitis virus, and with the characteristic Spike protein of SARS-CoV-2. Samples were prepared in two biofluids (saline solution and artificial saliva), in four concentrations, and deposited as 5-µL droplets on a supporting plate. The angles of maximal degree of linear polarization (DLP) of light diffusely scattered from dry residues were determined using Mueller polarimetry from87 samples at 405 nm and 514 nm. A polarimetric camera was used for imaging several samples under 380–420 nm illumination at angles similar to those of maximal DLP. Per-pixel image analysis included quantification and combination of polarization feature descriptors in 475 samples., [Main results] The angles (from sample surface) of maximal DLP were 3° for 405 nm and 6° for 514 nm. Similar viral particles that differed only in the characteristic spike protein of the SARS-CoV-2, their corresponding negative controls, fluids, and the sample holder were discerned at 10-degree and 15-degree configurations., [Significance] Polarimetric imaging in the visible spectrum may help improve fast, non-contact detection and identification of viral particles, and/or other microbes such as tuberculosis, in multiple dry fluid samples simultaneously, particularly when combined with other imaging modalities. Further analysis including realistic concentrations of real SARS-CoV-2 viral particles in relevant human fluids is required. Polarimetric imaging under visible light may contribute to a fast, cost-effective screening of SARS-CoV-2 and other pathogens when combined with other imaging modalities.

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings.

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings.

Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.

BACKGROUND: Obstructive failure of implanted shunts is the most common complication in the treatment of hydrocephalus. Biological material and debris accumulate in the inner walls of the valve and catheters block the normal flow of the drained cerebrospinal fluid causing severe symptoms with high morbidity and mortality. Unfortunately, at present, there is no effective preventive protocol or cleaning procedure available. OBJECTIVE: To assess whether externally applied, focused ultrasound beams can be used to resuspend deposits accumulated in brain shunts safely. METHODS: A computational model of an implanted brain shunt was implemented to test the initial design parameters of a system comprising several ultrasound transducers. Under laboratory conditions, configurations with 3 and 4 transducers were arranged in a triangle and square pattern with their radiation axis directed towards a target model of the device, 2 catheters and a brain shunt filled with water and deposited graphite powder. The ultrasound beams were then concentrated on the device across a head model. RESULTS: The computational model revealed that by using only 3 transducers, the acoustic field intensity on the valve was approximately twice that on the brain surface suggesting that acoustic cavitation could be selectively achieved. Resuspension of graphite deposits inside the catheters and the valve were then physically demonstrated and video-recorded with no temperature increase. CONCLUSION: The technology presented here has the potential to be used routinely as a noninvasive, preventive cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.

Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings.

Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.

BACKGROUND: Obstructive failure of implanted shunts is the most common complication in the treatment of hydrocephalus. Biological material and debris accumulate in the inner walls of the valve and catheters block the normal flow of the drained cerebrospinal fluid causing severe symptoms with high morbidity and mortality. Unfortunately, at present, there is no effective preventive protocol or cleaning procedure available. OBJECTIVE: To assess whether externally applied, focused ultrasound beams can be used to resuspend deposits accumulated in brain shunts safely. METHODS: A computational model of an implanted brain shunt was implemented to test the initial design parameters of a system comprising several ultrasound transducers. Under laboratory conditions, configurations with 3 and 4 transducers were arranged in a triangle and square pattern with their radiation axis directed towards a target model of the device, 2 catheters and a brain shunt filled with water and deposited graphite powder. The ultrasound beams were then concentrated on the device across a head model. RESULTS: The computational model revealed that by using only 3 transducers, the acoustic field intensity on the valve was approximately twice that on the brain surface suggesting that acoustic cavitation could be selectively achieved. Resuspension of graphite deposits inside the catheters and the valve were then physically demonstrated and video-recorded with no temperature increase. CONCLUSION: The technology presented here has the potential to be used routinely as a noninvasive, preventive cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.

BACKGROUND: Obstructive failure of implanted shunts is the most common complication in the treatment of hydrocephalus. Biological material and debris accumulate in the inner walls of the valve and catheters block the normal flow of the drained cerebrospinal fluid causing severe symptoms with high morbidity and mortality. Unfortunately, at present, there is no effective preventive protocol or cleaning procedure available. OBJECTIVE: To assess whether externally applied, focused ultrasound beams can be used to resuspend deposits accumulated in brain shunts safely. METHODS: A computational model of an implanted brain shunt was implemented to test the initial design parameters of a system comprising several ultrasound transducers. Under laboratory conditions, configurations with 3 and 4 transducers were arranged in a triangle and square pattern with their radiation axis directed towards a target model of the device, 2 catheters and a brain shunt filled with water and deposited graphite powder. The ultrasound beams were then concentrated on the device across a head model. RESULTS: The computational model revealed that by using only 3 transducers, the acoustic field intensity on the valve was approximately twice that on the brain surface suggesting that acoustic cavitation could be selectively achieved. Resuspension of graphite deposits inside the catheters and the valve were then physically demonstrated and video-recorded with no temperature increase. CONCLUSION: The technology presented here has the potential to be used routinely as a noninvasive, preventive cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.

HomeOfi es una plataforma informática que permite la interconexión entre profesionales que desean ofertar sus servicios por medio de tele consultas o venta de productos digitales, la misma posee información y datos de usuarios incluida su información bancaria, por lo que necesita considerar una estructura robusta de seguridad informática. El objetivo de esta investigación fue aplicar la Autentificación por Doble Factor para la plataforma informática HomeOfi, con el propósito de gestionar y validar la información de los usuarios, detectar y neutralizar ataques informáticos y garantizar el acceso exclusivo de sus usuarios autorizados. Para la validación de esta implementación se utilizó el método Delphi bajo las métricas de seguridad de la norma ISO 25010, para realizar este procesos se utilizaron dos ciclos, el primero sin la implementación de la Autentificación por Doble factor y el segundo con la implementación, dando como resultado en la primera interacción un cumplimento del 83% en general y en la segunda cumpliendo con un 100% de todas las métricas, mejorando así la seguridad informática de la empresa HomeOffice S.A.S.

Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings.

Optical spectroscopic techniques have been commonly used to detect the presence of biofilm-forming pathogens (bacteria and fungi) in the agro-food industry. Recently, near-infrared (NIR) spectroscopy revealed that it is also possible to detect the presence of viruses in animal and vegetal tissues. Here we report a platform based on visible and NIR (VNIR) hyperspectral imaging for non-contact, reagent free detection and quantification of laboratory-engineered viral particles in fluid samples (liquid droplets and dry residue) using both partial least square-discriminant analysis and artificial feed-forward neural networks. The detection was successfully achieved in preparations of phosphate buffered solution and artificial saliva, with an equivalent pixel volume of 4 nL and lowest concentration of 800 TU.mu L-1. This method constitutes an innovative approach that could be potentially used at point of care for rapid mass screening of viral infectious diseases and monitoring of the SARS-CoV- 2 pandemic.

Las emociones son estudiadas desde diferentes campos de la ciencia, como en neurociencia, psicología o fisiología y, a pesar de ello, sigue siendo en parte desconocido el cómo influyen en nuestro comportamiento o conducta. Este proyecto gira en torno a la piloerección (o “piel de gallina”) inducida por estímulos musicales. El objetivo es desarrollar un sistema de monitorización sincronizada de la piloerección y de las constantes cardiorespiratorias para el estudio de las emociones. Asimismo, el trabajo se ha centrado en el estudio de la relación entre la piloerección y la modificación de los parámetros biológicos medidos (la frecuencia cardíaca con el Pulse Sensor® y la conductividad de la piel mediante el GSR Sensor®). Para ello, se han realizado varios experimentos donde se busca provocar en el sujeto escalofríos y/o la mencionada piloerección al oír varias piezas musicales y visionar fragmentos de películas con su correspondiente banda sonora. Los resultados aportados en estas primeras pruebas muestran una variación en los parámetros obtenidos, que permiten establecer relaciones de correlación entre los estímulos y sus efectos biológicos. Palabras clave: piloerección, escalofrío, sistema nervioso, sistema respiratorio, actividad electrodérmica, frecuencia cardíaca, conductancia de la piel, sensibilidad, música, emoción, neurociencia, estímulo., Emotions are studied from different fields of science, such as in neuroscience, psychology or physiology and, in spite of that, the way they influence our behavior or conduct remains unknown. This project focuses on piloerection (or "goosebumps") induced by musical stimulation. The aim is to develop a synchronized monitoring system for piloerection and cardiorespiratory constants for the study of emotions. Likewise, the work has focused on the study of the correlation between piloerection and the modification of the biological parameters measured (the heart rate with the Pulse Sensor and the skin conductance through the GSR Sensor). For this, several experiments have been carried out where it is sought to cause chills and/or the mencioned piloerection in the person when hearing several musical pieces and watching fragments of films with their corresponding soundtrack. The results provided in these first tests show a variation in the parameters obtained, which allow establishing correlation relations between the stimuli and their biological effects.

Sistema para la neuroestimulación.Sistema de neuroestimulación comprendiendo una unidad externa de control (110) capaz de transferir energía e instrucciones a un grupo de neuroestimuladores (120,..., 120') implantables en un tejido (100) que constituyen u

Sistema para la neuroestimulación.Sistema de neuroestimulación comprendiendo una unidad externa de control (110) capaz de transferir energía e instrucciones a un grupo de neuroestimuladores (120,..., 120') implantables en un tejido (100) que constituyen u

Sistema para la neuroestimulación.Sistema de neuroestimulación comprendiendo una unidad externa de control (110) capaz de transferir energía e instrucciones a un grupo de neuroestimuladores (120,..., 120') implantables en un tejido (100) que constituyen u

Este trabajo describe los aspectos principales que se han usado para desarrollar un dispositivo de bajo presupuesto capaz de desarrollar manometrías anorrectales, usando para ello sistemas embebidos. La investigación es una parte fundamental de la medicina, se pretende con este trabajo aportar una herramienta que la facilite. La manometría anorrectal se realiza con un sistema de perfusión de agua, es un proceso indoloro y con pocos riesgos que proporciona una información interesante del funcionamiento de los esfínteres. El sistema está compuesto por varios subsistemas. Uno encargado del tratamiento de señales electromiográficas, compuesto de una etapa de amplificación aislada eléctricamente del resto del sistema, y de una etapa de filtrado para su digitalización. Otro subsistema se encarga de la amplificación y filtrado de cuatro canales de presión y otro último encargado de alimentar al resto de componentes. La digitalización se realiza con un ordenador de placa reducida programado adecuadamente para mostrarnos las señales por una pantalla HDMI. Se ha desarrollado un software con interfaz gráfica que muestra en tiempo real los valores de la prueba y permite su posterior estudio. Este sistema además de ser capaz de realizar manometrías anorrectales, también puede ser usado para realizar otro tipo de manometrías como por ejemplo la esofágica. El sistema es sencillo e intuitivo, puede ser manejado simplemente con un ratón o incluso una pantalla táctil., This work describes the main aspects we used to develop a low cost device to perform anorectal manometries using embedded systems. Research is a fundamental part of medicine, it is intended with this work to provide a tool that facilitates it. Anorectal manometry is performed with a water perfusion system, it is a painless and risk-free process that provides interesting information about the functioning of the sphincters. The system is composed of several subsystems. One responsible for the processing of electromyographic signals, consisting of an amplification stage electrically isolated from the rest of the system, and a filtering stage for digitization. Another subsystem is in charge of the amplification and filtering of four pressure channels and another last one in charge of the energy supply of the rest of the components. The digitalization is done with a single board computer properly programmed to show the signales through an HDMI screen. A software with graphical interface has been developed to show in real time some charts with the values of the test and allows its subsequent study. This system, in addition to being able to perform anorectal manometries, can also be used to perform other types of manometries, such as esophageal manometry. The system is simple and intuitive, it can be operated simply with a mouse or even a touch screen.

Las constantes vitales son parámetros que hay que tener en cuenta para conocer el diagnóstico clínico de personas y animales. Algunas de las constantes vitales más importantes son la frecuencia cardíaca, el nivel de oxigenación en la sangre, la frecuencia respiratoria y la temperatura corporal. Por otro lado, la utilización de animales para ciertas investigaciones es cada vez más frecuente en la ciencia médica. Por ejemplo, los ratones y las ratas son los animales más utilizados en los laboratorios. De la necesidad de monitorizar las constantes vitales en roedores durante intervenciones quirúrgicas y el alto impacto económico que produce la adquisición de estos instrumentos de monitorización, surge la idea de realizar, de forma compacta, un monitor de constantes vitales de bajo coste para estos animales. En este proyecto se desarrolla el diseño de un monitor de constantes vitales con el fin de ser utilizado, en un futuro, en los experimentos realizados en la Universidad De Sevilla. A lo largo del presente documento, podemos contemplar el diseño y fabricación de una placa de circuito impreso que incluye un electrocardiógrafo, un pulsioxímetro y un sistema para el control de temperatura corporal del animal. También, plasma el desarrollo software que permite representar, en tiempo real, las diferentes graficas de saturación de oxígeno, el electrocardiograma y la temperatura del animal.

Este trabajo describe los aspectos principales que se han usado para desarrollar un dispositivo de bajo presupuesto capaz de desarrollar manometrías anorrectales, usando para ello sistemas embebidos. La investigación es una parte fundamental de la medicina, se pretende con este trabajo aportar una herramienta que la facilite. La manometría anorrectal se realiza con un sistema de perfusión de agua, es un proceso indoloro y con pocos riesgos que proporciona una información interesante del funcionamiento de los esfínteres. El sistema está compuesto por varios subsistemas. Uno encargado del tratamiento de señales electromiográficas, compuesto de una etapa de amplificación aislada eléctricamente del resto del sistema, y de una etapa de filtrado para su digitalización. Otro subsistema se encarga de la amplificación y filtrado de cuatro canales de presión y otro último encargado de alimentar al resto de componentes. La digitalización se realiza con un ordenador de placa reducida programado adecuadamente para mostrarnos las señales por una pantalla HDMI. Se ha desarrollado un software con interfaz gráfica que muestra en tiempo real los valores de la prueba y permite su posterior estudio. Este sistema además de ser capaz de realizar manometrías anorrectales, también puede ser usado para realizar otro tipo de manometrías como por ejemplo la esofágica. El sistema es sencillo e intuitivo, puede ser manejado simplemente con un ratón o incluso una pantalla táctil., This work describes the main aspects we used to develop a low cost device to perform anorectal manometries using embedded systems. Research is a fundamental part of medicine, it is intended with this work to provide a tool that facilitates it. Anorectal manometry is performed with a water perfusion system, it is a painless and risk-free process that provides interesting information about the functioning of the sphincters. The system is composed of several subsystems. One responsible for the processing of electromyographic signals, consisting of an amplification stage electrically isolated from the rest of the system, and a filtering stage for digitization. Another subsystem is in charge of the amplification and filtering of four pressure channels and another last one in charge of the energy supply of the rest of the components. The digitalization is done with a single board computer properly programmed to show the signales through an HDMI screen. A software with graphical interface has been developed to show in real time some charts with the values of the test and allows its subsequent study. This system, in addition to being able to perform anorectal manometries, can also be used to perform other types of manometries, such as esophageal manometry. The system is simple and intuitive, it can be operated simply with a mouse or even a touch screen.

Un neuroestimulador es un dispositivo médico capaz de suministrar corriente controlada al tejido excitable objetivo. Al hacerlo, se puede lograr la modulación de la actividad del sistema nervioso. La técnica habitual más empleada se basa en el envío de pulsos de carga bifásica y balanceada. Este método permite la entrega y recogida de la misma cantidad de carga eléctrica, evitando dañar el tejido sobre el que se aplican los estímulos y ralentizar la degradación de los electrodos. El objetivo de este diseño es fabricar un estimulador neuronal que pueda usarse en estudios preclínicos de forma segura. El estimulador neuronal proporcionará capacidades para estimular simultáneamente al menos a través de dos canales independientes. Este dispositivo debe ser programable y capaz de entregar las formas de onda de estímulo deseadas a la llegada de una señal de disparo. El sistema estará eléctricamente aislado de la fuente de alimentación por seguridad eléctrica. La corriente inyectada debe ser precisa y capaz de proporcionar formas de onda de al menos 30 kHz. Este dispositivo eventualmente ayudará a la investigación de nuevos paradigmas de estimulación que contribuyan, entre otros, a mejorar el rendimiento actual del ojo biónico., A neurostimulator is a medical device capable of delivering controlled current to target excitable tissue. By doing so, modulation of the activity of the nervous system can be achieved. The most commonly used technique is based on sending biphasic and balanced load pulses. This method allows the delivery and collection of the same amount of electrical charge, avoiding damaging the tissue on which the stimuli are applied and slowing down the degradation of the electrodes. The aim of this design is to create a neuronal stimulator that can be safely used in preclinical studies. The neural stimulator will provide the ability to stimulate simultaneously through at least two independent channels. This device must be programmable and capable of delivering the desired stimulus waveforms at the arrival of a trigger signal. The system will be electrically isolated from the power supply for electrical safety. The injected current must be accurate and capable of providing waveforms of at least 30 kHz. This device will eventually help the investigation of new stimulation paradigms that contribute, among others, to improve the current performance of the bionic eye.

El problema de la investigación está determinado en tanto a que las mypes incumplen con el pago de la aportación a Essalud de sus trabajadores dependientes dado que es un beneficio que les otorga prestaciones de salud tanto a los trabajadores y sus derechos habientes. El objetivo general de la presente investigación se enfoca en determinar las implicancias de la deuda contributiva a Essalud y su reflejo en la gestión financiera de la mypes y así evitar que este tipo de empresas sean declaradas en quiebra por falta de liquidez como consecuencia del cobro de Essalud como empleadores morosos de la deuda no tributaria. Entre los resultados obtenidos encontramos que la población laboral en las mypes es relativamente joven entre los 18 años y los 28 años que no hacen uso de las prestaciones de salud, pero sus derechohabientes es decir su cónyuge y sus hijos si hacen uso lo que ocasiona ciertos problemas financieros a las mypes. Principales conclusiones a las que se ha arribado según puede verse: • Existe falta de voluntad para cumplir con sus obligaciones tributarias en el caso de la investigación se observa falta de pago a la aportación de Essalud. • Muchas mypes no contratan profesionales adecuadamente preparados (contadores) para que sean bien asesorados y poder así evitar estas contingencias o problemas financieros. • Las mypes deben llevar los registros contables adecuados a su tamaño económico para que tengan la oportunidad de vigilar permanentemente sus ingresos y así poder crecer empresarialmente. • La formalización de las MYPES nos permiten informar bien para evitar contingencias en el manejo financiero. Palabras Claves: Essalud, Aportación, Mypes, Tributario

The bypassing of degenerated photoreceptors using retinal neurostimulators is helping the blind to recover functional vision. Researchers are investigating new ways to improve visual percepts elicited by these means as the vision produced by these early devices remain rudimentary. However, several factors are hampering the progression of bionic technologies: the charge injection limits of metallic electrodes, the mechanical mismatch between excitable tissue and the stimulating elements, neural and electric crosstalk, the physical size of the implanted devices, and the inability to selectively activate different types of retinal neurons. Electrochemical and mechanical limitations are being addressed by the application of electromaterials such as conducting polymers, carbon nanotubes and nanocrystalline diamonds, among other biomaterials, to electrical neuromodulation. In addition, the use of synthetic hydrogels and cell-laden biomaterials is promising better interfaces, as it opens a door to establishing synaptic connections between the electrode material and the excitable cells. Finally, new electrostimulation approaches relying on the use of high-frequency stimulation and field overlapping techniques are being developed to better replicate the neural code of the retina. All these elements combined will bring bionic vision beyond its present state and into the realm of a viable, mainstream therapy for vision loss.

© 2017 IEEE. Retinal neuromodulation is an emerging therapeutic approach to restore functional vision to those suffering retinal photoreceptor degeneration. The retina encodes visual information and transmits it to the brain. Replicating this retinal code through electrical stimulation is essential to improving the performance of visual prostheses. In doing so, the first step relies on precise neural recordings from visual centers that allow studying the response of these neurons to electrical stimulation of the retina. This paper demonstrates the feasibility of a rat model to conduct highly reliable electrophysiological studies in the field of retinal neuromodulation. A disc electrode, implanted in the retrobulbar space was used to stimulate the retina of Long-Evans rats. Buzsaki multi-electro arrays were inserted in the superior colliculus (SC) to record electrical activity propagated from the retinal ganglion cells (RGCs). Activation thresholds calculated from local field potentials (visual cortex) and from neural spikes (SC) were contrasted. Both values were comparable to those in humans and in other animal models, and were slightly higher when estimated from SC recordings. However, differences were not statistically significant.

Retinal electrostimulation is promising a successful therapy to restore functional vision. However, a narrow stimulating current range exists between retinal neuron excitation and inhibition which may lead to misperformance of visual prostheses. As the conveyance of representation of complex visual scenes may require neighbouring electrodes to be activated simultaneously, electric field summation may contribute to reach this inhibitory threshold. This study used three approaches to assess the implications of relatively high stimulating conditions in visual prostheses: (1) in vivo, using a suprachoroidal prosthesis implanted in a feline model, (2) in vitro through electrostimulation of murine retinal preparations, and (3) in silico by computing the response of a population of retinal ganglion cells. Inhibitory stimulating conditions led to diminished cortical activity in the cat. Stimulus-response relationships showed non-monotonic profiles to increasing stimulating current. This was observed in vitro and in silico as the combined response of groups of neurons (close to the stimulating electrode) being inhibited at certain stimulating amplitudes, whilst other groups (far from the stimulating electrode) being recruited. These findings may explain the halo-like phosphene shapes reported in clinical trials and suggest that simultaneous stimulation in retinal prostheses is limited by the inhibitory threshold of the retinal ganglion cells.

El problema de la investigación está determinado en tanto a que las mypes incumplen con el pago de la aportación a Essalud de sus trabajadores dependientes dado que es un beneficio que les otorga prestaciones de salud tanto a los trabajadores y sus derechos habientes. El objetivo general de la presente investigación se enfoca en determinar las implicancias de la deuda contributiva a Essalud y su reflejo en la gestión financiera de la mypes y así evitar que este tipo de empresas sean declaradas en quiebra por falta de liquidez como consecuencia del cobro de Essalud como empleadores morosos de la deuda no tributaria. Entre los resultados obtenidos encontramos que la población laboral en las mypes es relativamente joven entre los 18 años y los 28 años que no hacen uso de las prestaciones de salud, pero sus derechohabientes es decir su cónyuge y sus hijos si hacen uso lo que ocasiona ciertos problemas financieros a las mypes. Principales conclusiones a las que se ha arribado según puede verse: • Existe falta de voluntad para cumplir con sus obligaciones tributarias en el caso de la investigación se observa falta de pago a la aportación de Essalud. • Muchas mypes no contratan profesionales adecuadamente preparados (contadores) para que sean bien asesorados y poder así evitar estas contingencias o problemas financieros. • Las mypes deben llevar los registros contables adecuados a su tamaño económico para que tengan la oportunidad de vigilar permanentemente sus ingresos y así poder crecer empresarialmente. • La formalización de las MYPES nos permiten informar bien para evitar contingencias en el manejo financiero. Palabras Claves: Essalud, Aportación, Mypes, Tributario

PURPOSE: to investigate the efficacy of electric field shaping in modulating the extent and activation threshold in retinal neurostimulation. This study aims to quantify the interference of neighbouring stimulation sites by assessing the shift in the activation threshold produced by a concomitant interfering stimulus.METHODS: electrical stimuli were applied to healthy retinae in a feline model (n=4) using a 24-channel electrode array surgically implanted in the suprachoroidal space. A 96-channel penetrating electrode array was used for recording cortical responses to a number of stimulation paradigms. Data were analyzed off-line. Concurrent monopolar and hexapolar stimuli were delivered at primary and interfering sites separated by up to 2.19 mm to evaluate electric cross-talk. The spike rate was fit to a sigmoidal curve to estimate the P50 threshold. The slope of the linear regression of the P50 value versus interfering current level was considered as a measure of cross-talk.RESULTS: concurrent monopolar stimulation produced a proportional drop in the P50 of approximately 20% of the interfering current level in presence of both a primary monopolar and hexapolar stimulus. On the other hand, hexapolar interference did not alter activation thresholds at the primary site.CONCLUSIONS: hexapolar stimulation reduces electric cross-talk between neighboring sites and represents a technique to reduce interference between individual stimulation sites. In contrast, concurrent monopolar stimulation produces a reduction of the activation threshold of stimuli delivered nearby. Thus, a single source of sub-threshold monopolar charge injection can provide benefit in the form of significant threshold reduction simultaneously at multiple stimulation sites.

Researchers around the globe are working towards restoring vision to the blind through the development of a visual neuroprosthesis. Overcoming physical, technical and biological limitations represents one of the main challenges for the scientific community and will eventually benefit the wellbeing of the recipients of these devices. Thus, understanding the physiological mechanisms of prosthetic vision plays a key role. In this context, in vivo electrophysiological studies are aiming to shed light on new stimulation paradigms that can potentially lead to improved visual perception. This paper describes a multi-viewpoint architecture of an experimental setup for the investigation of electrically evoked potentials in a retinal neuroprosthesis.

Researchers around the globe are working towards restoring vision to the blind through the development of a visual neuroprosthesis. Overcoming physical, technical and biological limitations represents one of the main challenges for the scientific community and will eventually benefit the wellbeing of the recipients of these devices. Thus, understanding the physiological mechanisms of prosthetic vision plays a key role. In this context, in vivo electrophysiological studies are aiming to shed light on new stimulation paradigms that can potentially lead to improved visual perception. This paper describes a multi-viewpoint architecture of an experimental setup for the investigation of electrically evoked potentials in a retinal neuroprosthesis.

Researchers around the globe are working towards restoring vision to the blind through the development of a visual neuroprosthesis. Overcoming physical, technical and biological limitations represents one of the main challenges for the scientific community and will eventually benefit the wellbeing of the recipients of these devices. Thus, understanding the physiological mechanisms of prosthetic vision plays a key role. In this context, in vivo electrophysiological studies are aiming to shed light on new stimulation paradigms that can potentially lead to improved visual perception. This paper describes a multi-viewpoint architecture of an experimental setup for the investigation of electrically evoked potentials in a retinal neuroprosthesis., Peer Reviewed

Visual prostheses are becoming a reality as a therapy to restore functional vision to the blind. New stimulation strategies and novel electrode designs are contributing to accelerate the development of such devices triggering the interest of scientists, clinicians and the blind community worldwide. In this scenario, there is a need for large animal models that are suitable for preclinical testing of retinal neuroprostheses. This study presents an electrophysiology assessment of an ovine model for single and simultaneous electrode stimulation from the suprachoroidal space, using symmetric biphasic current pulses with a monopolar return configuration. Visually and electrically evoked potentials were recorded using supradural surface electrodes, showing charge thresholds comparable to those in humans. This model represents an alternative to feline or canine models with analogous activation levels and an eye anatomy similar to that of humans.

Researchers around the globe are working towards restoring vision to the blind through the development of a visual neuroprosthesis. Overcoming physical, technical and biological limitations represents one of the main challenges for the scientific community and will eventually benefit the wellbeing of the recipients of these devices. Thus, understanding the physiological mechanisms of prosthetic vision plays a key role. In this context, in vivo electrophysiological studies are aiming to shed light on new stimulation paradigms that can potentially lead to improved visual perception. This paper describes a multi-viewpoint architecture of an experimental setup for the investigation of electrically evoked potentials in a retinal neuroprosthesis.