Infrared neurostimulation in ex-vivo rat sciatic nerve using 1470 nm wavelength.

OBJECTIVE: To design and implement a setup for ex-vivo optical stimulation for exploring the effect of several key parameters (optical power and pulse duration), activation features (threshold, spatial selectivity) and recovery characteristics (repeated stimuli) in peripheral nerves. APPROACH: A nerve chamber allowing ex-vivo electrical and optical stimulation was designed and built. A 1470 nm light source was chosen to stimulate the nerve. A photodiode module was implemented for synchronization of the electrical and optical channels. MAIN RESULTS: Compound Neural Action Potentials (CNAPs) were successfully generated with infrared light pulses of 200-2000 µs duration and power in the range of 3-10 W. These parameters determine a radiant exposure for stimulation in the range 1.59-4.78 J/cm2. Recruitment curves were obtained by increasing durations at a constant power level. Neural activation threshold is reached at a mean radiant exposure of 3.16 ± 0.68 J/cm2 and mean pulse energy of 3.79 ± 0.72 mJ. Repetition rates of 2-10 Hz have been explored. In 8 out of 10 sciatic nerves, repeated light stimuli induced a sensitisation effect in that the CNAP amplitude progressively grows, representing an increasing number of recruited fibres. In 2 out of 10 sciatic nerves, CNAPs were composed of a succession of peaks corresponding to different conduction velocities. SIGNIFICANCE: The reported sensitisation effect could shed light on the mechanism underlying Infrared NeuroStimulation (INS). Our results suggest that, in sharp contrast with electrical stimuli, optical pulses could recruit slow fibres early on. This more physiological order of recruitment opens the perspective for specific neuromodulation of fibre population who remained poorly accessible until now. Short high-power light pulses at wavelengths below 1.5 µm offer interesting perspectives for neurostimulation

The Falch Lecture 2018

International audienc

Automated versus manual sample inoculation in routine clinical microbiology: evaluation of the performance of the full automatic (FA) Inoqula instrument

International audienceThe process of plate streaking has been automated to improve the culture readings, isolation quality, and workflow of microbiology laboratories. However, instruments have not been well evaluated under routine conditions. We aimed to evaluate the performance of the fully automated InoqulA instrument (BD Kiestra B.V., The Netherlands) in the automated seeding of liquid specimens and samples collected using swabs with transport medium. We compared manual and automated methods according to the (i) within-run reproducibility using Escherichia coli-calibrated suspensions, (ii) intersample contamination using a series of alternating sterile broths and broths with >105 CFU/ml of either E. coli or Proteus mirabilis, (iii) isolation quality with standardized mixed bacterial suspensions of diverse complexity and a 4-category standardized scale (very poor, poor, fair to good, or excellent), and (iv) agreement of the results obtained from 244 clinical specimens. By involving 15 technicians in the latter part of the comparative study, we estimated the variability in the culture quality at the level of the laboratory team. The instrument produced satisfactory reproducibility with no sample cross-contamination, and it performed better than the manual method, with more colony types recovered and isolated (up to 11% and 17%, respectively). Finally, we showed that the instrument did not shorten the seeding time over short periods of work compared to that for the manual method. Altogether, the instrument improved the quality and standardization of the isolation, thereby contributing to a better overall workflow, shortened the time to results, and provided more accurate results for polymicrobial specimens

MODELO DE GESTIÓN DE LA DEMANDA ENERGÉTICA INTEGRAL

La gestión energética significa optimizar una de las más complejas e importantes técnicas crea ciones que conocemos: el sistema de energía. Existen una buena cantidad de métodos para la optimización de la generación de energía y su distribución. Por lo que el modelo de la demanda energética integral (DSM) es una estrategia para mejorar el sistema de energía en el lado del consumo. Se extiende desde la política energética, la economía experimental, la teoría de los agentes, la mejora de la eficiencia energética mediante software de soporte y aplicación, las tarifas de energía inteligente con incentivos para ciertos patrones de consumo, hasta los sofisticados sistemas de control en tiempo real de los recursos energéticos distribuidos. Este documento proporciona una visión general y una taxonomía para el desarrollo de un modelo sistemático integral de DSM, que analiza los distintos elementos de construcción, y ofrece un panorama sobre cómo emplear un modelo de análisis jerárquico de procesos y evaluación integral difusa para su implementación

Chronic Setup System for Continuous Monitoring of Epileptic Rats

This work presents a setup for chronic monitoring of spontaneous epileptic seizures in rats under kainic acid. The system allows to record the vagus nerve electroneurogram at 40 kS/s and the electroencephalogram at 250 S/s using an USB-6212 multifunction I/O-device. The system includes a video channel (20 fps) controlled by a Raspberry Pi 4 Model B. A slipring allows the rat to move freely. Quick cage cleaning is possible through a movable base. The chronic setup was tested on a Wistar rat after status epilepticus induction, using kainic acid. The system appears to be robust and reliable enough to record status epilepticus, making it suitable for more extended experiments in epileptic rats

Lopinavir/Ritonavir induces mitochondrial toxicity in HIV exposed uninfected children

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Micro Cuff Electrode Manufacture for Vagus Nerve Monitoring in Rats

This work describes the fabrication of a lab-made cuff electrode intended for rat vagus nerve electroneurography. The cuff electrode is built around 50 µm platinum wires contacts in tripolar configuration, 4mm contact spacing. The body is made of silicone rubber and four surgical threads. In vivo validation allowed to record respiration and cardiac related activity from the vagus nerve. The results show that our electrodes are a suitable low-cost alternative for our preclinical studies

Action Potential Detection Algorithm Adaptable to Individual Nerve and Recording Setup

This work presents an automated analysis algorithm to detect action potentials (APs) in a nerve and quantify its activity. The algorithm is based on template matching. The templates are automatically adapted to individual AP shapes that vary depending on the nerve fibers from which the AP originates, and the recording setup used. The algorithm was validated by quantifying vagus nerve activity recorded during in vivo experiments in a rat model. The MATLAB version of the code is available in open access on GitHub