Functional electrical stimulation-assisted cycle ergometry in the critically ill: protocol for a randomized controlled trial

This is the final version. Available from BMC via the DOI in this record. Background: Intensive care unit (ICU)-acquired weakness is the most important cause of failed functional outcome in survivors of critical care. Most damage occurs during the first week when patients are not cooperative enough with conventional rehabilitation. Functional electrical stimulation-assisted cycle ergometry (FES-CE) applied within 48 h of ICU admission may improve muscle function and long-term outcome. Methods: An assessor-blinded, pragmatic, single-centre randomized controlled trial will be performed. Adults (n = 150) mechanically ventilated for 7 days of critical care will be randomized (1:1) to receive either standard of care or FES-CE-based intensified rehabilitation, which will continue until ICU discharge. Primary outcome: quality of life measured by 36-Item Short Form Health Survey score at 6 months. Secondary outcomes: functional performance at ICU discharge, muscle mass (vastus ultrasound, N-balance) and function (Medical Research Council score, insulin sensitivity). In a subgroup (n = 30) we will assess insulin sensitivity and perform skeletal muscle biopsies to look at mitochondrial function, fibre typing and regulatory protein expression. Trial registration: ClinicalTrials.gov, NCT02864745. Registered on 12 August 2016.Grant Agency for Research in Healthcar

How organic farmers view their own practice: results from the Czech Republic

This paper addresses the development of organic agriculture in the Czech Republic, which is seen as a success story among post-communist countries. The relatively short history of organic farming and specific contextual factors raises questions about the nature and meaning of Czech organic farming. The goal of this study was to find out how farmers view their own practice, interpret its symbolic value, and construct its content. This empirical study uses Q methodology aimed at the identification of the collectively-shared perspectives belonging engaged actors. Data were gathered through semi-standardized interviews with Czech farmers registered in official organic scheme. The analysis emphasized three components, which are considered as three distinct perspectives possessed by organic farmers; that is, (1) organic farming as a way of life, (2) as an occupation, and (3) as a production of food of an alternative quality compared to conventional food. Each viewpoint entails a different understanding of what organic farming means; each then—when considered together—comprises the meaning of organic agriculture in the Czech Republic. The presented classification of the farmers holding the viewpoints contributes to the ongoing theoretical discussion regarding the nature of the current organic sector, its development and potential conventionalization

Simulation of the discharge propagation in a capillary tube in air at atmospheric pressure

International audienceThis paper presents simulations of an air plasma discharge at atmospheric pressure initiated by a needle anode set inside a dielectric capillary tube. We have studied the influence of the tube inner radius and its relative permittivity ε r on the discharge structure and dynamics. As a reference, we have used a relative permittivity ε r = 1 to study only the influence of the cylindrical constraint of the tube on the discharge. For a tube radius of 100 µm and ε r = 1, we have shown that the discharge fills the tube during its propagation and is rather homogeneous behind the discharge front. When the radius of the tube is in the range 300 to 600 µm, the discharge structure is tubular with peak values of electric field and electron density close to the dielectric surface. When the radius of the tube is larger than 700 µm, the tube has no influence on the discharge which propagates axially. For a tube radius of 100 µm, when ε r increases from 1 to 10, the discharge structure becomes tubular. We have noted that the velocity of propagation of the discharge in the tube increases when the front is more homogeneous and then, the discharge velocity increases with the decrease of the tube radius and ε r. Then, we have compared the relative influence of the value of tube radius and ε r on the discharge characteristics. Our simulations indicate that the geometrical constraint of the cylindrical tube has more influence than the value of ε r on the discharge structure and dynamics. Finally, we have studied the influence of photoemission processes on the discharge structure by varying the photoemission coefficient. As expected, we have shown that photoemission, as it increases the number of secondary electrons close to the dielectric surface, promotes the tubular structure of the discharge

Surface charge deposition inside a capillary glass tube by an atmospheric pressure discharge in air

This paper presents simulations of the dynamics of surface charging by an air plasma discharge at atmospheric pressure initiated by a needle anode inside a capillary glass tube. During the discharge propagation in the tube, the highest positive surface charge density is observed close to the point electrode. We have shown that during the discharge propagation, the positive surface charge is increasing behind the discharge front, while the electric field at the surface is decreasing. Then, we have studied the influence of the tube radius, its permittivity and the applied pulsed voltage on surface charges. We have shown that the surface charge density during the discharge propagation is inversely proportional to the tube radius and surface charge densities of 30–50 nC/cm2 for a tube with Rtube = 100 μm and an applied voltage of 12 kV have been obtained. We have also noted that a higher permittivity results in a higher surface charge density and a faster surface charge deposition. Then we have shown that the surface charge deposited is proportional to the applied voltage. Finally, at the end of the voltage pulse, our simulations indicate that the positive surface charge deposited during the discharge propagation in the tube decreases to very low values in few nanoseconds

Numerical simulation of transitions between back discharge regimes

ACLInternational audienceThis paper presents numerical simulations of transitions between back discharge regimes. Back discharge refers to any discharge initiated at or near a dielectric layer covering a passive electrode. In this work, a pinhole in a dielectric layer on a plane anode serves as a model for back discharge activity. We have studied transitions between back discharge regimes by varying the surface charge density on the dielectric layer and the electric field in front of the pinhole. From the variation of these two independent parameters, the back discharge regimes have been depicted as a mode diagram inspired by the experimental study of Masuda and Mizuno. The resulting diagram includes the different discharge regimes that are commonly observed in experiments. The propagation of a positive ionizing wave inside the pinhole toward its edge, and the resulting formation of a plasma zone at its exit constitute the onset stage of back discharge. From this stage, the transitions to volume discharge or surface discharge can occur. The volume discharge regime consists of the propagation of a discharge in space toward the cathode which can be superimposed with the propagation of a discharge above the dielectric layer surface. The diagram reveals the conditions for transitions between back discharge regimes. © 2014 EDP Sciences

Numerical Simulation of Back Discharge: Influence of Pinhole Geometry on the Regime Transitions

International audienceThis paper presents numerical simulation of back discharge activity that is modelled at a pinhole in a dielectric layer on plane anode. First, for a given pinhole geometry, the transitions between back discharge regimes have been depicted as a mode diagram. Then, we have studied the influence of the dielectric layer thickness on the regime transitions. We have shown that increase in the layer thickness (within range of 0.02\textendash0.2 mm) promotes the back discharge development. Finally, we have studied the influence of `crater configuration'. We have shown that `crater shape' favours the back discharge ignition, whereas limits the resulting discharge development

Electric field development in positive and negative streamers on dielectric surface

International audienc