Light transmittance in human atrial tissue and transthoracic illumination in rats support translatability of optogenetic cardioversion of atrial fibrillation.

Background: Optogenetics could offer a solution to the current lack of an ambulatory method for the rapid automated cardioversion of atrial fibrillation (AF), but key translational aspects remain to be studied.

Objective: To investigate whether optogenetic cardioversion of AF is effective in the aged heart and whether sufficient light penetrates the human atrial wall.

Methods: Atria of adult and aged rats were optogenetically modified to express light-gated ion channels (i.

Optical ventricular cardioversion by local optogenetic targeting and LED implantation in a cardiomyopathic rat model.

Aims: Ventricular tachyarrhythmias (VTs) are common in the pathologically remodelled heart. These arrhythmias can be lethal, necessitating acute treatment like electrical cardioversion to restore normal rhythm. Recently, it has been proposed that cardioversion may also be realized via optically controlled generation of bioelectricity by the arrhythmic heart itself through optogenetics and therefore without the need of traumatizing high-voltage shocks.

An automated hybrid bioelectronic system for autogenous restoration of sinus rhythm in atrial fibrillation.

Because of suboptimal therapeutic strategies, restoration of sinus rhythm in symptomatic atrial fibrillation (AF) often requires in-hospital delivery of high-voltage shocks, thereby precluding ambulatory AF termination. Continuous, rapid restoration of sinus rhythm is desired given the recurring and progressive nature of AF. Here, we present an automated hybrid bioelectronic system for shock-free termination of AF that enables the heart to act as an electric current generator for autogenous restoration of sinus rhythm.

Abnormal Myocardial Contractility After Pediatric Heart Transplantation by Cardiac MRI.

Acute cellular rejection (ACR) compromises graft function after heart transplantation (HTX). The purpose of this study was to describe systolic myocardial deformation in pediatric HTX and to determine whether it is impaired during ACR. Eighteen combined cardiac magnetic resonance imaging (CMR)/endomyocardial biopsy (EMBx) examinations were performed in 14 HTX patients (11 male, age 13.

Optogenetic termination of ventricular arrhythmias in the whole heart: towards biological cardiac rhythm management.

Aims: Current treatments of ventricular arrhythmias rely on modulation of cardiac electrical function through drugs, ablation or electroshocks, which are all non-biological and rather unspecific, irreversible or traumatizing interventions. Optogenetics, however, is a novel, biological technique allowing electrical modulation in a specific, reversible and trauma-free manner using light-gated ion channels. The aim of our study was to investigate optogenetic termination of ventricular arrhythmias in the whole heart.

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle after arterial switch operation for dextro-transposition of the great arteries.

Right ventricular (RV) volume and function evaluation is essential in the follow-up of patients after arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA). Cardiac magnetic resonance (CMR) imaging using the Simpson's method is the gold-standard for measuring these parameters. However, this method can be challenging and time-consuming, especially in congenital heart disease.

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle in tetralogy of Fallot.

Background: Cardiac magnetic resonance using the Simpson method is the gold standard for right ventricular volumetry. However, this method is time-consuming and not without sources of error. Knowledge-based reconstruction is a novel post-processing approach that reconstructs the right ventricular endocardial shape based on anatomical landmarks and a database of various right ventricular configurations.

Results from craniocaudal carotid body tumor resection: should it be the standard surgical approach?

Objectives: To evaluate results after carotid body tumor (CBT) surgery using a novel dissection technique.

Methods: A retrospective analysis of all operated CBT in the last 6 years was carried out and results were compared with the current literature and our previous series, which reported another 111 cases operated on until 2005.

Results: Forty-five CBTs were removed in 41 (56% hereditary cases) patients (seven Shamblin I, 22 II, and 16 III).

Abiotic transformation of catechol and 1-naphthol in aqueous solution-influence of environmental factors.

The abiotic transformation of catechol and 1-naphthol singly and in mixtures was tested in sterile Tris-HCl buffer with regard to several environmental factors including temperature (7 degrees C, 20 degrees C and 30 degrees C), lighting conditions, pH (between 7.0 and 8.5) and dissolved oxygen (at partial pressures of 0.

Pressure-drops control strategy in a fixed-bed reactor.

This paper presents a strategy to control pressure-drops (head loss) in a biofilter designed according to the "Mist-Foam" concept. This concept is based on the mixing of the gaseous substrate and a liquid nutrient solution with an atomization nozzle to generate a mist passing subsequently through a synthetic polyurethane foam. In this type of bioreactor, the microbial growth reduces progressively the empty bed volume of the biofilter and causes an increase in the pressure-drops.

High-rate continuous biodegradation of concentrated chlorinated aliphatics by a durable enrichment of methanogenic origin under carrier-dependent conditions.

The simultaneous biodegradation of toxic compounds in mixtures is a major current concern. To bioremediate a toxic mixture, we designed a strategy combining an ad-sorbent carrier with an ecological and nutritional system which allowed work close to heavily polluted conditions in nature. Starting from a methanogenic community, we developed a microbial consortium acclimated to a mixture of about 30 chlorinated aliphatics in a fixed-film stationary-bed bioreactor.

Computation of pH evolution versus ionic products concentration in a fermentation broth.

An algorithm developed for pH computation has been tested to calculate the theoretical pH changes in a culture medium during the course of a fermentation. A divergence between the computed pH value and the value measured with the electrode allows us to highlight the presence of undetected ionic products. The calculation with the algorithm by means of a computer requires only the knowledge of the ionic properties of the substrates and detected products and existing thermodynamic constants.

Implementation of an adaptive controller for the startup and steady-state running of a biomethanation process operated in the CSTR mode.

An adaptive control algorithm has been implemented on a biomethanation process to maintain propionate concentration, a stable variable, at a given low value, by steering the dilution rate. It was thereby expected to ensure the stability of the process during the startup and during steady-state running with an acceptable performance. The methane pilot reactor was operated in the completely mixed, once-through mode and computer-controlled during 161 days.

Fermentation of citrate by Lactobacillus plantarum in the presence of a yeast under acid conditions.

At pH 3.6, Lactobacillus plantarum is unable to grow on citrate or to ferment it in the absence of another carbon source such as glucose. In a defined medium containing glucose and citrate, with a higher concentration of the former than the latter, as in many fermented alcoholic beverages, L.

Trophic relationships between Saccharomyces cerevisiae and Lactobacillus plantarum and their metabolism of glucose and citrate.

Glucose and citrate are two major carbon sources in fruits or fruit juices such as orange juice. Their metabolism and the microorganisms involved in their degradation were studied by inoculating with an aliquot of fermented orange juice a synthetic model medium containing glucose and citrate. At pH 3.

Transient response of a solid-liquid model biological fluidised bed to a step change in fluid superficial velocity.

The evolution of a solid-liquid model biological fluidised bed under a step change in fluid superficial velocity is described. During a transient step change, the fluidised bed divides into a top zone which remains at the initial porosity and a bottom zone which settles at the final porosity. The interface of discontinuity in porosity moves progressively upwards through the fluidised bed.

Computation of physicochemical parameters, namely pH, in complex (bio)chemical systems: extension to gas-liquid systems.

The first model has been proposed to compute, in complex liquid (bio)chemical systems, a number of physicochemical parameters, namely pH, concentration of one of any chemical species, partition between acid-base forms, global charge, or ionic strength, assuming the physicochemical equilibrium state. The extension of the present model, described here, permits moreover the computation of gas-liquid distributions, specific gas volumes, or total pressures. The model solely requires the knowledge of existing thermodynamic constants and of the concentration of every chemical species other than the species under examination.

Problematics and stability of on-line pH measurements in anaerobic environments: The jellied combined electrode.

Discrepancies of one pH unit and more have been observed after a few days, between continuous on-line in situ pH measurements and instant off-line pH measurements during anaerobic digestion of an agroindustrial wastewater. Concomitantly, the electrical resistance across the porous diaphragm of the on-line electrode increased, and a black clogging developed on its diaphragm. Measurements of the relative liquid junction potential in KCl or Na(2)S solutions excluded that high concentrations of ions such as, K(+), Na(+), Cl(-), HS(-), or S(2-) were the major cause of the drifts in pH values.

Adaptive control of anaerobic digestion processes-a pilot-scale application.

A simple adaptive control algorithm, for which theoretical stability and convergence properties had been previously demonstrated, has been successfully implemented on a biomethanation pilot reactor. The methane digester, operated in the CSTR mode was submitted to a shock load, and successfully computer controlled during the subsequent transitory state.

Quantitative method based on energy and mass balance for estimating substrate transient accumulation in activated sludge during wastewater treatment.

To calculate the transient accumulation of soluble organic matter in activated sludge, an equation based on COD and respirometry is described. In this approach the difference between the actual utilized organic matter and the metabolized matter is expressed as substrate transient accumulation. The amount of substrate generated by the lysis of dead microorganisms was taken into account, and the metabolized organic matter was expressed in two main endergonic functions of O(2) consumption, that is, assimilation and maintenance.

Computation of physiochemical parameters, inter alia, pH, in complex (bio)chemical systems.

Generic equations and algorithms are derived to compute, in complex (bio)chemical systems at equilibrium, the following physicochemical parameters: pH (or the concentration of any chemical species), partitions between acid and base forms, global charge, molar mean charges, ionic strength, and molar mean contributions to ionic strength. The model only requires the knowledge of existing thermodynamic constants and of the composition of the system in chemical species as the sum of the different forms other than the species under examination. It takes ionic strength aspects into consideration.

Subcellular distribution of enzymes in the yeast saccharomycopsis lipolytica, grown on n-hexadecane, with special reference to the omega-hydroxylase.

The subcellular localization of the omega-hydroxylase of Saccharomycopsis lipolytica was assessed by the analytical fractionation technique, originally described by de Duve C., Pressman, B.C.