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An important brain re-wiring, the so-called cross-modal plasticity, occurs during progression of retinal degenerative diseases to compensate for lack of visual input. The visual cortex does not go 'unused', instead it is devoted to processing other sensory modalities. In this study we recorded, in the visual cortex, visual- and auditory-evoked potentials in an anesthetized murine model of retinal degeneration. The latency to the first peak of the recorded local field potentials was used to assess the speed of the response. Visual responses occurred significantly faster in the control group. Conversely, auditory responses appeared significantly faster in animals with retinal degeneration. This suggests the compensatory neural rewiring is optimizing the performance of other sensory modalities, hearing in this case. This phenomenon may play an important role in visual neuro-rehabilitation. Whether or not it can promote or deter the interpretation of artificially encoded neural signals from a visual prosthesis remains to be studied.

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.

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·μL−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. Instituto de Salud Carlos III COV20-00080 and COV20-00173 Ministerio de Ciencia e Innovación EQC2019-006240-P Comisión Europea JRC HUMAINT project

Este trabajo reporta la presencia inusual de especies de la familia Carangidae en los desembarcaderos de la provincia de Pisco (13.5° S), departamento de Ica, ocurridos durante el evento El Niño costero 2017. Se observaron 4 especies: Caranx caballus, Caranx caninus, Oligoplites saurus y Selene brevoortii capturadas con el arte de pesca “cortina agallera”. Durante el periodo de El Niño costero 2017 en el área de estudio se registraron temperaturas superiores a los 26 °C y salinidades moderadamente elevadas (> 35.1 ups), condiciones que habrían favorecido el desplazamiento de estas especies, frecuentes en el norte del Perú, hacia latitudes superiores.

Electrical stimulation of excitable cells provides therapeutic benefits for a variety of medical conditions, including restoration of partial vision to those blinded via some types of retinal degeneration. To improve visual percepts elicited by the current technology, researchers are conducting acute electrophysiology experiments, mainly in cats. However, the rat can provide a model of a range of retinal diseases and possesses a sufficiently large eye to be used in this field. This article presents a long-term anesthetic protocol to enable electrophysiology experiments to further the development of visual prostheses. Six Long-Evans rats (aged between 14 and 16 weeks) were included in this study. Surgical anesthesia was maintained for more than 15 h by combining constant intravenous infusion of ketamine (24.0-34.5 mg/kg/h), xylazine (0.9-1.2 mg/kg/h), and inhaled isoflurane in oxygen (

Ministerio de Ciencia e Innovación RTI2018-094465-J-I00 Unión Europea, Horizon 2020, Marie Sklodowska-Curie Grant Agreement No. 746526

Resumen: Introducción: La evaluación de la asociación de síntomas entre el reflujo gastroesofágico y los eventos cardiorrespiratorios no está aún resuelta. Este artículo describe una aproximación conservadora para la decisión del tratamiento quirúrgico antirreflujo mediante el análisis de la asociación de síntomas. Métodos: Cuarenta y tres neonatos con síntomas cardiorrespiratorios potencialmente asociados al reflujo se sometieron a una monitorización cardiorrespiratoria y de pH-impedancia esofágica. Se consideraron 3 índices, el índice de síntomas (IS), el índice de sensibilidad de síntomas (ISS) y la probabilidad de asociación de síntomas (PAS). Asimismo, se adoptó una estrategia conservadora para la aplicación de cirugía antirreflujo, de manera que solo se consideró el tratamiento quirúrgico en aquellos pacientes con valor significativo en los 3 índices. Se contrastaron retrospectivamente estos índices y el índice de síntomas binomial (ISB) frente a la decisión de cirugía antirreflujo utilizando diferentes ventanas de asociación. Resultados: Trece pacientes mostraron algún índice con valor significativo pero solo 2 se sometieron al tratamiento quirúrgico. Tanto el IS como el ISS mostraron una tendencia creciente al aumentar el ancho de la ventana de asociación. El PAS presentó fuertes variaciones aleatorias frente a pequeños cambios del enventanado. El ISB presentó el mejor resultado con la ventana de dos minutos (κ = 0,78). Conclusiones: La patología bajo estudio mejora con la madurez del individuo. Sin embargo, la severidad de los síntomas cardiorrespiratorios puede amenazar la vida del neonato y, por lo tanto, en algunas ocasiones se deben considerar tratamientos invasivos para proteger la vida. El ISB proporciona una buena predicción de la combinación de valores positivos del IS, el ISS y el PAS, lo que puede ayudar a mejorar las decisiones clínicas. Sin embargo, son necesarios futuros estudios que prueben el ISB como un predictor óptimo de los eventos clínicos. Abstract: Introduction: The evaluation of symptom association between gastroesophageal reflux and cardiorespiratory events in preterm infants remains unclear. This paper describes a conservative approach to decision-making of anti-reflux surgery through symptom association analysis. Methods: Forty-three neonates with potentially reflux-related cardiorespiratory symptoms underwent synchronized esophageal impedance-pH and cardiorespiratory monitoring. Three indices were considered to evaluate symptom association, the symptom index (SI), the symptom sensitivity index (SSI) and the symptom association probability (SAP). A conservative strategy was adopted regarding the decision of anti-reflux surgery, and therefore, patients were scheduled for laparoscopic Nissen fundoplication if the three indices showed a positive assessment of symptom association. Retrospectively, these indices and the binomial symptom index (BSI) were contrasted against the decision of anti-reflux surgery using different windows of association. Results: Thirteen patients showed positive symptom association but only two underwent anti-reflux surgery. The SI and the SSI showed an increasing trend with the width of the window of association. The SAP was affected randomly by slightly altering the windowing parameters. The BSI showed the best performance with the two-minute window (κ =0.78) Conclusions: The pathology under study is known to improve with maturity. However, the severity of cardiorespiratory symptoms may threaten the neonate's life and therefore, in some occasions, invasive treatments must be considered to protect life. The BSI provides a good prediction of a combination of positive SI, SSI and SAP, which may improve clinical decisions. However, further clinical studies are required to prove the BSI as an optimal predictor of clinical outcomes.

The Peruvian bay scallop Argopecten purpuratus is a key resource of the Peruvian diving fishery that has long been harvested along the Peruvian and Chilean coastline. In the last decade, Sechura Bay (North Peru) has developed into a hotspot for its cultivation, which represents an important socio-economic activity for the region. Scallops are cultivated on the bottom and may potentially function as ecosystem engineers in the system by providing settling substrate to other organisms in an otherwise soft-bottom habitat. Community analysis (permutational multivariate analysis of variance, similarity percentage analysis and abundance-biomass comparison) was combined with trophic modelling (Ecopath with Ecosim) to compare the current system state with pre-culture conditions, to evaluate the impact of scallop culture on both the benthic community and overall ecosystem functioning. The results suggest the following effects due to the massive culture: (1) a significant change in benthic community composition; (2) an increase in the predator biomass, paralleled by a decrease in the biomass of their competitors; (3) a change in species diversity and maturity; (4) a system increase in size (in terms of biomass and total flows); and (5) a decrease in energy cycling, indicative of the direct impact of scallop culture on the system’s flow structure and functioning. The results suggest that a further expansion of scallop culture may cause the benthic species composition to further shift towards a hard-bottom-associated community, essentially altering the system’s structure and functioning. These results are expected to aid the process of suggesting limits to culture and the ecological carrying capacity of the bay’s system.

Low vision and ultimately, profound blindness can result from impaired connectivity or dysfunctional elements in the neural pathways transferring visual information to the brain. Blindness is one of the most debilitating sensory impairments affecting tens of millions of people worldwide, with its prevalence constantly increasing as the global population ages. Immense progress in the last decade has revealed the potential of electronic devices to restore visual perception through applying artificial electrical stimulation to neurons along the pathway from the eye to the brain. Prostheses implanted in the visual cortex, optic nerve, lateral geniculate nucleus, and the retina have led to elicitation of visual perceptions and improvement in functional visual ability in individuals with severe vision disorders. Here, we review the progress in visual bionics, focusing on retinal and cortical prostheses, and discuss key challenges and next-generation technologies.

Anorectal manometry is a diagnostic technique used to investigate the correct mechanical performance of the internal anal sphincter (IAS). By distending the rectal ampulla while recording changes in the luminal pressure, this method allows for characterizing the anorectal reflex. It can also provide, indirectly, information about the electrical activity of the IAS. In this study, seventeen neonates having 24-hour delayed passage of meconium or presenting distal intestinal obstruction symptoms underwent anorectal manometry to discard Hirschsprung’s disease. All patients had normal anorectal reflex. The time delay between stimulation of the rectal ampulla and the relaxation of the anal canal was studied. The average period of the pressure fluctuations was 5.44 ± 0.13s. The overall duration of the relaxation time was 9.71 ± 0.21s. The maximum lag between the onset of the stimulus and the relaxation of the IAS was 2.90 s, and was achieved when the stimulus was applied following a local maximum of the pressure wave. The existence of a refractory period during the suprathreshold depolarization of smooth muscle cells can explain the evidence of a temporal delay between the stimulus and the mechanical response. In occasions, relaxation appeared first distally. This phenomenon can be explained by the arrangement and morphology of bipolar cells, which may evidence the anisotropic propagation of the mechanical activity. These data may contribute to depict the alterations in excitability underlying the relaxation reflex by means of manometric recording of the anal canal.

Anorectal manometry is a common technique for investigating the performance of the anal canal. The absence of the rectosphincteric reflex may determine the existence of important pathologies. Animal models are essential to assess the efficacy of new therapies as well as to provide a better understanding of the physiological mechanisms underlying intestinal motility. This paper describes an inexpensive laboratory setup for experimental anorectal manometry that consists of a water-perfused customized catheter, a signal acquisition and processing system, and a personal computer with a software program to display biosignals. Twenty Wistar rats, ten males and ten females, were anesthetized using a ketamine–xylazine intraperitoneal injection. The basal tone of the anorectal sphincter and the rectosphincteric reflex were studied. In basal conditions, two frequency peaks were found, one at 0.015 ± 0.007 Hz and the other at 0.363 ± 0.057 Hz, corresponding to slow and ultraslow pressure waves, respectively. The maximum resting pressure varied between 37.8 and 109.0 mmHg. Anorectal relaxations derived from stimulation of the rectum wall dropped to 82.65 ± 14.61 % of the pressure level prior to stimulation. The overall period of the relaxation wave was 10.22 ± 2.91 s. Differences between genders were found: autonomous pressure oscillations were significantly slower in female rats whereas the period of the relaxation wave was significantly shorter in male subjects. Overall, the mechanical description of the anal canal in Wistar rats is similar to that in humans, especially to that in newborns. Therefore, it represents a good animal model for the investigation of anorectal motility.

Research in the field of visual prosthesis is advancing quickly with several groups around the world joining efforts to produce more effective and safe implants. In particular, new stimulation strategies are being investigated to elicit more meaningful percepts of light and to safely increase the visual acuity achieved by these devices. The synergy between in vitro, in silico and in vivo electrophysiology techniques can be exploited to accelerate research outcomes and to make them quickly available to the recipients of these implants.

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 implants have proven their ability to restore visual sensation to people with degenerative retinopathy, characterized by photoreceptor cell death and the retina's inability to sense light. Retinal bionics operate by electrically stimulating the surviving neurons in the retina, thus triggering the transfer of visual sensory information to the brain. Suprachoroidal implants were first investigated in Australia in the 1950s. In this approach, the neuromodulation hardware is positioned between the sclera and the choroid, thus providing significant surgical and safety benefits for patients, with the potential to maintain residual vision combined with the artificial input from the device. Here we review the latest advances and state of the art devices for suprachoroidal prostheses, highlight future technologies and discuss challenges and perspectives towards improved rehabilitation of vision.

Retinal neuroprostheses or ‘bionic eyes’, aim to restore patterned vision to those with vision loss by electrically stimulating the remaining neurons in the degenerate retina. Despite considerable progress over the last two decades, such devices generally stimulate indiscriminately both the ‘ON’ and ‘OFF’ visual pathways in the retina, conveying highly non-physiological signals to the brain.

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.

Gastroesophageal reflux (GER) disease is a serious complication of the upper gastrointestinal tract. Cardiorespiratory symptoms such as apnea, oxygen desaturation and bradycardia may be related to GER. Thus, the recommended diagnostic methodology in pediatric patients requires 24-h synchronized esophageal and cardiorespiratory monitoring. However, there is no computer tool available for this purpose and therefore, researchers and physicians are forced to seek for customized solutions. This paper presents an open source computer program for the analysis of symptom association. It allows a convenient visualization of the biological signals and implements the three main metrics for symptom association, that is, the symptom index, the symptom sensitivity index and the symptom association probability. This software represents a flexible solution and will facilitate caregivers an easy assessment of the existence of temporal association between GER and cardiorespiratory episodes. This would ideally reduce inappropriate medical and surgical treatments and would provide an early diagnosis of the medical condition.

Researchers continue to develop visual prostheses towards safer and more efficacious systems. However limitations still exist in the number of stimulating channels that can be integrated. Therefore there is a need for spatial and time multiplexing techniques to provide improved performance of the current technology. In particular, bright and high-contrast visual scenes may require simultaneous activation of several electrodes. In this research, a 24-electrode array was suprachoroidally implanted in three normally-sighted cats. Multi-unit activity was recorded from the primary visual cortex. Four stimulation strategies were contrasted to provide activation of seven electrodes arranged hexagonally: simultaneous monopolar, sequential monopolar, sequential bipolar and hexapolar. Both monopolar configurations showed similar cortical activation maps. Hexapolar and sequential bipolar configurations activated a lower number of cortical channels. Overall, the return configuration played a more relevant role in cortical activation than time multiplexing and thus, rapid sequential stimulation may assist in reducing the number of channels required to activate large retinal areas.

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 neighboring 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 offline. 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 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 subthreshold monopolar charge injection can provide benefit in the form of significant threshold reduction simultaneously at multiple stimulation sites.

Summary Gastroesophageal monitoring is limited to 96 hours by the current technology. This work presents a computational model to investigate symptom association in gastroesophageal reflux disease with larger data samples proving important deficiencies of the current methodology that must be taking into account in clinical evaluation. A computational model based on Monte Carlo analysis was implemented to simulate patients with known statistical characteristics Thus, sets of 2000 10-day-long recordings were simulated and analyzed using the symptom index (SI), the symptom sensitivity index (SSI), and the symptom association probability (SAP). Afterwards, linear regression was applied to define the dependency of these indexes with the number of reflux, the number of symptoms, the duration of the monitoring, and the probability of association. All the indexes were biased estimators of symptom association and therefore they do not consider the effect of chance: when symptom and reflux were completely uncorrelated, the values of the indexes under study were greater than zero. On the other hand, longer recording reduced variability in the estimation of the SI and the SSI while increasing the value of the SAP. Furthermore, if the number of symptoms remains below one-tenth of the number of reflux episodes, it is not possible to achieve a positive value of the SSI. A limitation of this computational model is that it does not consider feeding and sleeping periods, differences between reflux episodes or causation. However, the conclusions are not affected by these limitations. These facts represent important limitations in symptom association analysis, and therefore, invasive treatments must not be considered based on the value of these indexes only until a new methodology provides a more reliable assessment.

Bacterial internalization is an important process in the pathogenesis of infectious diseases in which nuclear factor kappaB (NF-kappaB) plays a prominent role. We present pharmacological evidence indicating that in bovine endothelial cells (BEC) the internalization of Staphylococcus aureus, a pathogenic bacterium that causes mastitis in bovine cattle, was associated with the activation of NF-kappaB. The internalization of S. aureus increased when BEC were stimulated with alpha-tumour necrosis factor (TNF-alpha) or beta-interleukin 1 (IL-1beta) which are known activators of NF-kappaB. SN50 (an inhibitor peptide of NF-kappaB nuclear translocation) and BAY 11-7083 (a chemical that inhibits the IkappaBalpha phosphorylation) caused significant reduction in S. aureus intracellular number, indicating that its internalization was associated with the NF-kappaB activity. Furthermore, specific inhibition of c-Jun N-terminal kinase with SP600125 (SP) or p-38 with SB203580 (SB) did not cause any change in the S. aureus intracellular number compared with the untreated control. Finally, TNF-alpha treatment of BEC after the addition of both SP and SB, induced a significant increase in S. aureus internalization above the control value. These data indicate that NF-kappaB activity is associated with S. aureus internalization and suggest that this transcription factor may play a role in the pathophysiology of bovine mastitis caused by this bacterium.

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.

Introduction: The evaluation of symptom association between gastroesophageal reflux and cardiorespiratory events in preterm infants remains unclear. This paper describes a conservative approach to decision-making of anti-reflux surgery through symptom association analysis. Methods: Forty-three neonates with potentially reflux-related cardiorespiratory symptoms underwent synchronized esophageal impedance-pH and cardiorespiratory monitoring. Three indices were considered to evaluate symptom association, the symptom index (SI), the symptom sensitivity index (SSI) and the symptom association probability (SAP). A conservative strategy was adopted regarding the decision of anti-reflux surgery, and therefore, patients were scheduled for laparoscopic Nissen fundoplication if the three indices showed a positive assessment of symptom association. Retrospectively, these indices and the binomial symptom index (BSI) were contrasted against the decision of anti-reflux surgery using different windows of association. Results: Thirteen patients showed positive symptom association but only two underwent anti-reflux surgery. The SI and the SSI showed an increasing trend with the width of the window of association. The SAP was affected randomly by slightly altering the windowing parameters. The BSI showed the best performance with the two-minute window (κ = 0.78). Conclusions: The pathology under study is known to improve with maturity. However, the severity of cardiorespiratory symptoms may threaten the neonate's life and therefore, on some occasions, invasive treatments must be considered to protect life. The BSI provides a good prediction of a combination of positive SI, SSI and SAP, which may improve clinical decisions. However, further clinical studies are required to prove the BSI as an optimal predictor of clinical outcomes. Resumen: Introducción: La evaluación de la asociación de síntomas entre el reflujo gastroesofágico y los eventos cardiorrespiratorios no está aún resuelta. Este artículo describe una aproximación conservadora para la decisión del tratamiento quirúrgico anti-reflujo mediante el análisis de la asociación de síntomas. Métodos: Cuarenta y tres neonatos con síntomas cardiorrespiratorios potencialmente asociados al reflujo se sometieron a una monitorización cardiorrespiratoria y de pH-impedancia esofágica. Se consideraron tres índices, el índice de síntomas (IS), el índice de sensibilidad de síntomas (ISS) y la probabilidad de asociación de síntomas (PAS). Asimismo, se adoptó una estrategia conservadora para la aplicación de cirugía anti-reflujo, de manera que solo se consideró el tratamiento quirúrgico en aquellos pacientes con valor significativo en los tres índices. Se contrastaron retrospectivamente estos índices y el índice de síntomas binomial (ISB) frente a la decisión de cirugía anti-reflujo utilizando diferentes ventanas de asociación. Resultados: Trece pacientes mostraron algún índice con valor significativo pero solo dos se sometieron al tratamiento quirúrgico. Tanto el IS como el ISS mostraron una tendencia creciente al aumentar el ancho de la ventana de asociación. El PAS sufrió fuertes variaciones aleatorias frente a pequeños cambios del enventanado. El ISB presentó el mejor resultado con la ventana de dos minutos (κ = 0.78). Conclusiones: La patología bajo estudio mejora con la madurez del individuo. Sin embargo, la severidad de los síntomas cardiorrespiratorios puede amenazar la vida del neonato y por lo tanto, en algunas ocasiones se deben considerar tratamientos invasivos para proteger la vida. El ISB proporciona una buena predicción de la combinación de valores positivos del IS, ISS y PAS, lo que puede ayudar a mejorar las decisiones clínicas. Sin embargo, son necesarios futuros estudios que prueben al ISB como un predictor óptimo de los eventos clínicos.

Previous contributions suggested that gastroesophageal reflux can be modeled in terms of a Poisson process. This study aims to provide empirical data to validate this statement in pediatric patients so that computational models can be broadly used as an alternative for research. A retrospective review of 63 pediatric patients who underwent 24-hour impedance-pH monitoring to discard gastroesophageal reflux disease was conducted in this study. Patients were grouped by age as preterm (21), infants (21), and children (21). All the tracings were analyzed by a trained physician who identified the reflux entry and the bolus clearance time of each episode. The time between reflux episodes was tested against three probability distributions (gamma, exponential and inverse Gaussian) whereas the bolus clearance time was tested against a normal probability distribution. Parameters were estimated using the maximum likelihood method. The Kolmogorov-Smirnov test and the Kullback-Leibler divergence were computed to evaluate the goodness of fit. One-way analysis of variance was applied to compare results along the three groups. Exponential fitting for inter-reflux time was successful in 90.48% of children older than 1 year. The overall reflux rate was 57.58 reflux episodes per day whereas the mean bolus clearance time ranged between 10.87 in preterm subjects and 12.05 in children, showing a good Gaussian fitting. The time between reflux episodes can be modeled in terms of a Poisson process in non tube-fed patients, whereas the bolus clearance time follows a normal distribution in all cases.

Gastroesophageal reflux may become pathologic when it produces symptoms resulting in complications. Apnea, cough, aspirative pneumonias, bradycardia, etc, are common associated cardiorespiratory complications. It is frequent in premature babies and may occur in healthy newborn, and its complications may require hospitalization and intensive care. Gastroesophageal impedance-pH monitoring is a usual method to diagnose what is known as gastroesophageal reflux disease. Multi-parametric studies include 24-hour impedance-pH recording and were complemented with cardiorespiratory monitoring in this study. It would ideally allow an early diagnosis reducing reflux-related morbimortality and shortening hospital stays, what would also lower hospital expenses and unnecessary treatments. Symptom association analysis was applied to determine the degree of temporal association between cardiorespiratory episodes and gastroesophageal reflux. Temporal lags between both events were computed and compared with the size of the window of association resulting the window larger than the lag.

Background The evaluation of symptom association in gastroesophageal reflux is an open problem. The scientific literature reports important deficiencies and clinicians are claiming a new methodology. This article provides an optimal method for the evaluation of symptom association, the binomial symptom index (BSI). Methods A mathematical description of the BSI was presented for the study of association and causality. A total of n = 850 000 patients were simulated using a Monte Carlo model to perform a two-way sensitivity analysis. The average and the standard deviation of the BSI were evaluated in groups of 5000 patients with the same values of the reflux rate, symptom rate, association ratio, window of association, and monitoring time in order to contrast their influence on the estimator. Key Results The BSI decreased with the number of reflux episodes when there was association, and remained constant and below 40% when there was not. The standard deviation was no higher than 40% and decreased with the reflux or symptom rates, and more sharply with the monitoring time, reaching approximately 0% for 50 days. A window length matching the characteristic reflux-symptom lag maximized the overall BSI and minimized its dispersion. Twenty-four hour and 96-h monitorings allowed detecting association ratios of 50% and 25%, respectively. Conclusions & Inferences The BSI is a simple and reliable index for the evaluation of symptom association that considers all the parameters under analysis. Defining an appropriate cut-off value, the BSI can provide a measure of probability and strength of association simultaneously.

Gastroesophageal monitoring is limited to 96 hours by the current technology. This work presents a computational model to investigate symptom association in gastroesophageal reflux disease with larger data samples proving important deficiencies of the current methodology that must be taking into account in clinical evaluation. A computational model based on Monte Carlo analysis was implemented to simulate patients with known statistical characteristics Thus, sets of 2000 10-day-long recordings were simulated and analyzed using the symptom index (SI), the symptom sensitivity index (SSI), and the symptom association probability (SAP). Afterwards, linear regression was applied to define the dependency of these indexes with the number of reflux, the number of symptoms, the duration of the monitoring, and the probability of association. All the indexes were biased estimators of symptom association and therefore they do not consider the effect of chance: when symptom and reflux were completely uncorrelated, the values of the indexes under study were greater than zero. On the other hand, longer recording reduced variability in the estimation of the SI and the SSI while increasing the value of the SAP. Furthermore, if the number of symptoms remains below one-tenth of the number of reflux episodes, it is not possible to achieve a positive value of the SSI. A limitation of this computational model is that it does not consider feeding and sleeping periods, differences between reflux episodes or causation. However, the conclusions are not affected by these limitations. These facts represent important limitations in symptom association analysis, and therefore, invasive treatments must not be considered based on the value of these indexes only until a new methodology provides a more reliable assessment.

Investigators around the world are working on retinal neurostimulation as it may restore functional vision to the blind. The image is captured by a camera and after being processed, a series of electrical stimuli are applied to the surviving ganglion cells of the retina. This visual perception is expected to have low resolution. Therefore, there is a need of new algorithms that present the information contained in a visual scene understandable to humans. This study presents a novel multi-resolution algorithm based on wavelet analysis to extract the useful features of an image. Participants in this experiment were able to configure a filter bank to complete a set of everyday tasks. This study shows that wavelet-based algorithms may facilitate improved functional performance in prosthetic vision.

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. Universidad de Sevilla. Grado en Ingeniería Electrónica, Robótica y Mecatrónica

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. Universidad de Sevilla. Grado en Ingeniería de Tecnologías Industriales

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. Universidad de Sevilla. Grado en Ingeniería de las Tecnologías de Telecomunicación