Labview 2010

Participants walked and were perturbed on a split-belt treadmill (Figure 1; Bertec, Columbus, OH, USA). The treadmill speed was set to 1.2 m/s throughout the experiment, except during perturbations. We tested acceleration and deceleration perturbations that were induced by accelerating or decelerating the right belt by 0.5 m/s for 400 ms, which occurred immediately after right foot contact. The rate of change in belt speed was set to 20 m/s² for both acceleration and deceleration perturbations. The resultant time interval between right foot contact and the perturbation was 73 ± 3 ms for the acceleration perturbation and 65 ± 5 ms for the deceleration perturbation. The difference in perturbation timing might be due to the mechanical property of the apparatus. The magnitude, timing, and duration of the perturbation were determined through preliminary tests that were large enough to evoke reflexive muscle responses, but small enough not to induce any dangerous injuries and falls. The timing of the perturbations was controlled online using custom-written software in LabVIEW 2010 (National instruments Inc., Austin, TX, USA). The perturbation was induced if the ground reaction force had exceeded 50 N for 10 ms.

Hemodynamic data were measured by the indwelling catheters and recorded continuously (LabVIEW 2010, National Instruments, Austin, TX, USA). Coronary perfusion pressure (CPP) was estimated by subtracting the diastolic right atrial pressure from the diastolic femoral arterial pressure [18 (link)]. During resuscitation, we used the mean right atrial pressure and the mean femoral pressure due to the missing pulsatility in the blood pressure signal of the non-contracting ventricle. The measured cerebral oximetry values were normalized to the baseline (BL) values. Blood samples were collected at baseline, after 10 and 30 min and every full hour following ROSC (PR 10, PR 30 and PR60-PR360). Blood gas analysis was performed for arterial and mixed venous samples using a standard blood gas analyzer (ABL 700; Radiometer, Copenhagen, Denmark). Blood cell counting was carried out using an automated blood cell machine at baseline and 6 h following ROSC (Celltac-alpha VET MEK-6550K; Nihon Koden, Rosbach, Germany).

Continuous evolution experiments were performed with the same bioreactor setup as described in Section “Bioreactor Batch Cultivations.” During the continuous process mode, feed medium was constantly added from a reservoir with a peristaltic pump (Watson Marlow 120 U/DV 200 RPM, Falmouth, UK) and simultaneously, the same volume of the fermentation broth was harvested with a second pump. An accurate feed rate was automatically ensured by a controller (Figure 1) that continuously monitored the weight of the harvested material (laboratory scale Combics 3, Sartorius, Göttingen, Germany). It converted the measured mass flow into volume flow (density of the biosuspension: 1.01 kg L⁻¹) and adjusted the influx by regulating the pumping speed when the deviation from the desired flux got larger than 2%. The reaction volume of 1.2 L was kept constant by monitoring the weight of the total reactor using a laboratory scale (Combics 3, Sartorius, Göttingen, Germany) and by automatically adjusting the speed of the harvest pump with a second controller which allowed deviation from the setpoint weight of 0.2%. This setup enabled setting dilution rates with a precision of 0.01 h⁻¹. The regulation scheme was implemented in a custom process control system using the software LabVIEW (LabVIEW® 2010, National Instruments, Austin, TX, USA).

EtCO₂ was measured by using an analogue side-stream capnograph (Medlab CAP 10; Medlab GmbH, Stutensee, Germany) with infrared absorption technology and sampled at 400 Hz in SignalExpress 14.0.0 (National Instruments, Austin, Texas) after conversion in an analogue-to-digital converter (NIDAQPad-6015, National Instruments). Flow was measured continuously by Dräger Infinity ID with hot-wire anemometer technology. Haemodynamic data, including blood pressure obtained via a 20G catheter in the left radial artery, were downloaded from GE Solar 8000i (GE Healthcare, Chicago, Illinois, US) and analysed in a custom-made program (LabView 2010, National Instruments). CO was measured with oesophageal Doppler (DP-12 probe; Cardio Q; Deltex Medical, Chichester, UK), which continuously measures flow velocity in the descending aorta and thus rapid changes in stroke volume (SV) [21 (link)]. The Doppler probe was thoroughly fixed in the position that gave the best signal and maximum peak velocity of the aortic flow, and the signal was closely observed throughout experiments. SV measurements were downloaded beat-by-beat by the serial output.

To ensure the safety of the participants during tDCS in the MRI, temperature was monitored on all subjects throughout the duration of the scan (approximately an hour and 15 minutes). Specifically, four T1C 1.7 mm diameter fibre optic temperature sensors (Neoptix, Quebec, Canada) were located under both electrode pads and the nearest cable chokes. Temperature was monitored in real time with a calibrated Reflex signal conditioner (Neoptix, Quebec, Canada) and a custom data collection program written in LabVIEW 2010 (National Instruments).

The ground reaction forces (GRF) were measured by means of four force transducers (Arsalis, Belgium) located under each corner of a modified commercial treadmill (h/p/Cosmos-Stellar, Germany, belt surface: 1.60x0.65 m). The forces were filtered with an 8^th order Bessel dual low pass filter with a cut-off frequency of 20 Hz. The non-linearity was <1% of full scale, and the crosstalk between vertical and horizontal GRF <1%.
The GRF signal was digitized with a 16-bit A/D convertor at a sampling rate of 500 Hz. The amplified GRF signals were processed by means of a computer with dedicated software (LABVIEW 2010, National Instruments, Austin, TX, USA). The decomposition algorithm proposed by Meurisse et al. [26 (link)] was used to determine the beginning and the end of the DC phase, the front FC time and the back foot TO time, and the vertical component of the GRF acting upon each limb during the double contact phase.
The GRFs were used to compute the velocity and the displacement of the CoM [27 (link)]. Data were normalized relative to the stride duration, 0% corresponding to the initial contact of the right foot and 100% corresponding to the next contact of the same foot.