Closed-loop parameter optimization for patient-specific phrenic nerve stimulation.

BACKGROUND: Ventilator-induced diaphragm dysfunction occurs rapidly following the onset of mechanical ventilation and has significant clinical consequences. Phrenic nerve stimulation has shown promise in maintaining diaphragm function by inducing diaphragm contractions. Non-invasive stimulation is an attractive option as it minimizes the procedural risks associated with invasive approaches. However, this method is limited by sensitivity to electrode position and inter-individual variability in stimulation thresholds. This makes clinical application challenging due to potentially time-consuming calibration processes to achieve reliable stimulation. METHODS: We applied non-invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. A closed-loop system recorded the respiratory flow produced by stimulation and automatically adjusted the electrode position and stimulation amplitude based on the respiratory response. By iterating over electrodes, the optimal electrode was selected. A binary search method over stimulation amplitudes was then employed to determine an individualized stimulation threshold. Pulse trains above this threshold were delivered to produce diaphragm contraction. RESULTS: Nine healthy volunteers were recruited. Mean threshold stimulation amplitude was 36.17 ± 14.34 mA (range 19.38-59.06 mA). The threshold amplitude for reliable nerve capture was moderately correlated with BMI (Pearson's r = 0.66, p = 0.049). Repeating threshold measurements within subjects demonstrated low intra-subject variability of 2.15 ± 1.61 mA between maximum and minimum thresholds on repeated trials. Bilateral stimulation with individually optimized parameters generated reliable diaphragm contraction, resulting in significant inhaled volumes following stimulation. CONCLUSION: We demonstrate the feasibility of a system for automatic optimization of electrode position and stimulation parameters using a closed-loop system. This opens the possibility of easily deployable individualized stimulation in the intensive care setting to reduce ventilator-induced diaphragm dysfunction.

Differences in whole blood before and after hemodialysis session of subjects with chronic kidney disease measured by Raman spectroscopy.

This study aimed to identify differences in the composition of whole blood of patients with chronic kidney disease (CKD), before and after a hemodialysis session (HDS), and possible differences in blood composition between stages and between genders using Raman spectroscopy and principal component analysis (PCA). Whole blood samples were collected from 40 patients (20 women and 20 men), before and after a HDS. Raman spectra were obtained and the spectra were evaluated by PCA and partial least squares (PLS) regression. Mean spectra and difference spectrum between the groups were calculated: stages Before and After HDS, and gender Women and Men, which had their most intense peaks identified. Stage: mean spectra and difference spectrum indicated positive peaks that could be assigned to red blood cells, hemoglobin and deoxi-hemoglobin in the group Before HDS. There was no statistically significant difference by PCA. Gender: mean spectra and difference spectrum Before HDS indicated positive peaks that could be assigned to red blood cells, hemoglobin and deoxi-hemoglobin with greater intensity in the group Women, and negative peaks to white blood cells and serum, with greater intensity in the group Men. There was statistically significant difference by PCA, which also identified the peaks assigned to white blood cells, serum and porphyrin for Women and red blood cells and amino acids (tryptophan) for Men. PLS model was able to classify the spectra of the gender with 83.7% accuracy considering the classification per patient. The Raman technique highlighted gender differences in pacients with CKD.

Divergent Pd-catalyzed Functionalization of 4-Oxazolin-2-ones and 4-Methylene-2-oxazolidinones and Synthesis of Heterocyclic-Fused Indoles.

Palladium-catalyzed functionalization was presently performed on two building blocks: 4-oxazolin-2-ones and 4-methylene-2-oxazolidinones. Direct Heck arylation of 4-oxazolin-2-ones led to a series of 5-aryl-4-oxazolin-2-ones, including analogues with N-chiral auxiliary, in an almost quantitative yield. The Pd(II)-catalyzed homocoupling reaction of 4-oxazolin-2-ones provided novel heterocyclic across-ring dienes. Meanwhile, the intramolecular cross-coupling of N-aryl-4-methylene-2-oxazolidinones furnished a series of oxazolo[3,4-a]indol-3-ones. Further functionalization of 4-methylene-2-oxazolidinones afforded substituted indoles and heterocyclic-fused indoles with aryl, bromo, carbinol, formyl, and vinyl groups. A computational study was carried out to account for the behavior of the formylated derivatives. The currently developed methodology was applied to a new formal total synthesis of ellipticine.

Non-invasive phrenic nerve stimulation to avoid ventilator-induced diaphragm dysfunction in critical care.

BACKGROUND: Diaphragm muscle atrophy during mechanical ventilation begins within 24 h and progresses rapidly with significant clinical consequences. Electrical stimulation of the phrenic nerves using invasive electrodes has shown promise in maintaining diaphragm condition by inducing intermittent diaphragm muscle contraction. However, the widespread application of these methods may be limited by their risks as well as the technical and environmental requirements of placement and care. Non-invasive stimulation would offer a valuable alternative method to maintain diaphragm health while overcoming these limitations. METHODS: We applied non-invasive electrical stimulation to the phrenic nerve in the neck in healthy volunteers. Respiratory pressure and flow, diaphragm electromyography and mechanomyography, and ultrasound visualization were used to assess the diaphragmatic response to stimulation. The electrode positions and stimulation parameters were systematically varied in order to investigate the influence of these parameters on the ability to induce diaphragm contraction with non-invasive stimulation. RESULTS: We demonstrate that non-invasive capture of the phrenic nerve is feasible using surface electrodes without the application of pressure, and characterize the stimulation parameters required to achieve therapeutic diaphragm contractions in healthy volunteers. We show that an optimal electrode position for phrenic nerve capture can be identified and that this position does not vary as head orientation is changed. The stimulation parameters required to produce a diaphragm response at this site are characterized and we show that burst stimulation above the activation threshold reliably produces diaphragm contractions sufficient to drive an inspired volume of over 600 ml, indicating the ability to produce significant diaphragmatic work using non-invasive stimulation. CONCLUSION: This opens the possibility of non-invasive systems, requiring minimal specialist skills to set up, for maintaining diaphragm function in the intensive care setting.

Effects of the habitat on anuran blood parasites in the Eastern Brazilian Amazon.

Biological interactions play an important role in regulating and maintaining natural populations. Like most interactions, parasitism may be influenced by environmental conditions. Therefore, changes caused by human activity may drastically affect the equilibrium of the assemblages of parasitized organisms (hosts). Herein, we described the composition of hemoparasites of anurans from two distinct environments: forest and oil palm plantations. We identified the most frequent groups of blood parasites, and whether infections differ between habitats (forest and plantation) and between microhabitats (arboreal or terrestrial). We collected 128 anurans, of which 46 (36%) were parasitized by hemoparasites. The genus Trypanosoma spp. was found in 30% (n = 37/128) of the infected anurans in both habitats, recorded mostly in terrestrial anurans in oil palm plantations. Apicomplexa hemoprotozoans were also found in 13% (n=17/128) of the anurans, which mainly were terrestrial species collected in oil palm plantations. There was no difference in parasitism between the two assemblies and between the studied microhabitats. This is the first study that has analyzed the ecological relationship between anurans as hosts and their blood parasites, in a region under intense anthropic pressure, in the Brazilian Amazon.

In vitro activity of essential oils against adult and immature stages of Ctenocephalides felis felis.

Essential oils (EOs) are considered a new class of ecological products aimed at the control of insects for industrial and domestic use; however, there still is a lack of studies involving the control of fleas. Ctenocephalides felis felis, the most observed parasite in dogs and cats, is associated with several diseases. The aim of this study was to evaluate the in vitro activity, the establishment of LC50 and toxicity of EOs from Alpinia zerumbet (Pers.) B. L. Burtt & R. M. Sm, Cinnamomum spp., Laurus nobilis L., Mentha spicata L., Ocimum gratissimum L. and Cymbopogon nardus (L.) Rendle against immature stages and adults of C. felis felis. Bioassay results suggest that the method of evaluation was able to perform a pre-screening of the activity of several EOs, including the discriminatory evaluation of flea stages by their LC50. Ocimum gratissimum EO was the most effective in the in vitro assays against all flea stages, presenting adulticide (LC50 = 5.85 µg cm-2), ovicidal (LC50 = 1.79 µg cm-2) and larvicidal (LC50 = 1.21 µg cm-2) mortality at low doses. It also presented an excellent profile in a toxicological eukaryotic model. These findings may support studies involving the development of non-toxic products for the control of fleas in dogs and cats.

Gait Segmentation Method Using a Plantar Pressure Measurement System with Custom-Made Capacitive Sensors.

Gait analysis has been widely studied by researchers due to the impact in clinical fields. It provides relevant information on the condition of a patient's pathologies. In the last decades, different gait measurement methods have been developed in order to identify parameters that can contribute to gait cycles. Analyzing those parameters, it is possible to segment and identify different phases of gait cycles, making these studies easier and more accurate. This paper proposes a simple gait segmentation method based on plantar pressure measurement. Current methods used by researchers and clinicians are based on multiple sensing devices (e.g., multiple cameras, multiple inertial measurement units (IMUs)). Our proposal uses plantar pressure information from only two sensorized insoles that were designed and implemented with eight custom-made flexible capacitive sensors. An algorithm was implemented to calculate gait parameters and segment gait cycle phases and subphases. Functional tests were performed in six healthy volunteers in a 10 m walking test. The designed in-shoe insole presented an average power consumption of 44 mA under operation. The system segmented the gait phases and sub-phases in all subjects. The calculated percentile distribution between stance phase time and swing phase time was almost 60%/40%, which is aligned with literature reports on healthy subjects. Our results show that the system achieves a successful segmentation of gait phases and subphases, is capable of reporting COP velocity, double support time, cadence, stance phase time percentage, swing phase time percentage, and double support time percentage. The proposed system allows for the simplification of the assessment method in the recovery process for both patients and clinicians.

Phototherapy effect on the muscular activity of regular physical activity practitioners.

Clinical investigations have demonstrated the effectiveness of phototherapy on the muscle activity. The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on the tibialis anterior muscle of regular physical activity practitioners by electromyographic, biomechanical, and biochemical (lactate) analysis. Double-blind controlled clinical trials were conducted with 12 healthy females, regular physical activity practitioners, between 18 and 30 years. The LLLT application (780 nm, 30 mW, 0.81 J/point, beam area of 0.2 cm(2), 27 s, ≈ 29 points) in the tibialis anterior muscle occurred after the delimitation of the points on every 4 cm(2) was held. It was observed that (a) a significant torque increase (p < 0.05) post-LLLT compared to the values after placebo therapy at the beginning of resistance exercise, (b) both muscle torque (isokinetic) and median frequency (EMG) showed a faster decay of the signals collected after placebo and laser treatment when compared to control values, (c) no significant change in torque in the strength test of five repetitions, (d) a significant muscle activity decrease (p < 0.05) after laser therapy compared to control values, and (e) an increase in lactate levels post-LLLT (p < 0.05) after 30 min of exercise. It is concluded that the LLLT increased the muscle torque at the beginning of the exercise and maintained the levels of lactate after resistance exercise. Therefore, the LLLT with the parameters used in this study can be utilized in rehabilitation to improve muscle performance in elite athletes.

High and low pitch sound stimuli effects on heart-brain coupling.

This study aimed to explore the influence of sound stimulation on heart rate and the potential coupling between cardiac and cerebral activities. Thirty-one participants underwent exposure to periods of silence and two distinct continuous, non-repetitive pure tone stimuli: low pitch (110 Hz) and high pitch (880 Hz). Electroencephalography (EEG) data from electrodes F3, F4, F7, F8, Fp1, Fp2, T3, T4, T5, and T6 were recorded, along with R-R interval data for heart rate. Heart-brain connectivity was assessed using wavelet coherence between heart rate variability (HRV) and EEG envelopes (EEGE). Heart rates were significantly lower during high and low-pitch sound periods than in silence (p < 0.002). HRV-EEGE coherence was significantly lower during high-pitch intervals than silence and low-pitch sound intervals (p < 0.048), specifically between the EEG Beta band and the low-frequency HRV range. These results imply a differential involvement of the frontal and temporal brain regions in response to varying auditory stimuli. Our findings highlight the essential nature of discerning the complex interrelations between sound frequencies and their implications for heart-brain connectivity. Such insights could have ramifications for conditions like seizures and sleep disturbances. A deeper exploration is warranted to decipher specific sound stimuli's potential advantages or drawbacks in diverse clinical scenarios.

Tourniquets, types and techniques in emergency prehospital care: A narrative review.

Massive uncontrolled hemorrhage is an important cause of preventable death in trauma. Therefore, applying an arterial tourniquet (TQ) is recommended as a pre-hospital measure to control bleeding after severe traumatic bleeding. Limb TQ applies circumferential compression proximally to the injury site to compress the arteries, resulting in blood flow and consequently hemorrhage interruption. The use of commercial tourniquets (C-TQ), which are designed, tested, and registered to control hemorrhages in pre-hospital care, is a consensus. However, they are still uncommon in many prehospital emergency services and the overall level of evidence in most studies is low. This narrative review aimed to characterize the importance of tourniquets use in prehospital emergency care and its application techniques. Furthermore, it proposes to stimulate the development of new devices, more accessible and easier to use, to suggest new directions of studies and medical education demands, with manikin and simulation development.

Thermodynamic and Ab Initio Design of Multicomponent Alloys Based on (Fe50Mn30Co10Cr10)-xBx (x = 0, 5, 7, 10, and 15 at.%).

Multicomponent alloys have attained general interest in recent years due to their remarkable performance. Non-equiatomic alloys with boron addition as an interstitial element are being studied, exhibiting outstanding mechanical properties. In order to estimate the mechanical behavior of potential alloys, thermodynamic and ab initio calculations were utilized in this work to investigate phase stability and stacking fault energy (SFE) for (Fe50Mn30Co10Cr10)-xBx (x = 0, 5, 7, 10, and 15 at.%) systems. Thermodynamic experiments revealed two structural variations of borides, M2B(C16) with a tetragonal structure and M2B(CB) with an orthorhombic structure. Borides precipitate when boron content increases, and the FCC matrix becomes deficient in Mn and Cr. According to ab initio calculations, the presence of boron in the FCC and HCP structures primarily disrupts the surroundings of the Fe and Mn atoms, resulting in an increased distortion of the crystal lattice. This is related to the antiferromagnetic condition of the alloys. Furthermore, for alloys with a low boron concentration, the stacking fault energy was found to be near 20 mJ/m2 and greater than 50 mJ/m2 when 10 and 15 at.% boron was added. As boron concentrations increase, M2B borides are formed, generating changes in the matrix composition prone to fault-induced phase transitions that could modify and potentially impair mechanical properties.

Effect of the rest interval duration between contractions on muscle fatigue.

BACKGROUND: We aimed to investigate the effect of rest interval, between successive contractions, on muscular fatigue. METHODS: Eighteen subjects performed elbow flexion and extension (30 repetitions) on an isokinetic dynamometer with 80º of range of motion. The flexion velocity was 120º/s, while for elbow extension we used 5 different velocities (30, 75, 120, 240, 360º/s), producing 5 different rest intervals (2.89, 1.28, 0.85, 0.57 and 0.54 s). RESULTS: We observed that when the rest interval was 2.89 s there was a reduction in fatigue. On the other hand, when the rest interval was 0.54 s the fatigue was increased. CONCLUSIONS: When the resting time was lower (0.54 s) the decline of work in the flexor muscle group was higher compared with different rest interval duration.

Respiratory biofeedback accuracy in chronic renal failure patients: a method comparison.

OBJECTIVE: To analyse respiratory biofeedback effects on respiratory muscle strengthening in chronic renal failure patients. DESIGN: Randomized controlled study. SETTING: Nephrology and dialysis centre. SUBJECTS AND INTERVENTION: Forty-one end-stage renal patients on haemodialysis treatment were allocated into three groups: control (n = 10), G-1 (inspiratory muscle training using Threshold IMT device; n = 16) and G-2 (biofeedback; n = 15) and given respiratory muscle training (three sessions/week for six weeks). MAIN MEASURES: Forced vital capacity (FVC), expiratory volume in the first second (FEV(1)), FEV(1)/FVC ratio, maximal voluntary ventilation (MVV) and maximal inspiratory (MIP) and expiratory (MEP) pressures were measured before and after the respiratory muscle training programme. RESULTS: Both training methods were efficient since we found an increase after training in the FVC in the G-1 group (from 2.45 ± 0.17 to 2.85 ± 0.16; P = 0.001) and in the G-2 group (from 2.35 ± 0.19 to 2.55 ± 0.19; P = 0.007), in the FEV(1) in G-1 (from 2.18 ± 0.16 to 2.46 ± 0.14; P = 0.01) and in G-2 (from 1.97 ± 0.17 to 2.20 ± 0.15; P < 0.0001), MIP in G-1 (from 70.63 ± 4.03 to 108.75 ± 7.41; P < 0.0001) and in G-2 (from 67.67 ± 5.02 to 96.33 ± 8.30; P < 0.001) and MEP in G-1 (from 73.13 ± 5.10 to 82.50 ± 6.74; P = 0.007) and in G-2 (from 67.67 ± 5.41 to 76.00 ± 4.29; P = 0.002). CONCLUSIONS: Respiratory biofeedback is efficient as a respiratory muscle training modality for patients with chronic renal failure.

Gait Subphases Classification Based on Hidden Markov Models using in-shoes Capacitive Pressure Sensors: Preliminary Results.

Gait cycle analysis is widely practiced to determine alterations of normal walking. The challenge is to choose the ideal systems that suit the studies. One possibility is to measure the interaction of the sole and the support surface and detect gait events related to the positioning of the foot. This work proposes a gait subphase classification based on Hidden Markov Model that identifies gait stance subphases from a foot pressure measurement. A sensorized insole was used to record the pressure under the foot with eight custom-made capacitive sensors. Tests were performed on six volunteers with a 10-meter trial test. Mean cadence and stance/swing ratio were calculated. These parameters match the normal range for the age of the volunteers found in the literature. The results show that the proposed model can classify the gait in 5 subphases using the Center of Pressure (CoP) anteroposterior position and velocity as input. Changes in the slope of the CoP marks the step between subphases. Clinical Relevance- Most gait studies are performed in highly equipped gait laboratories. Due to technical requirements and the high cost of implementing a gait laboratory, access to these services is difficult for a large population. For this reason, it is necessary to develop equipment, devices, and algorithm to further study pathological and healthy gait.

Exploring Silicone Rubber Skin with Embedded Customizable Shape Capacitive Sensors to Enable Haptic Capabilities on Upper Limb Prosthetics.

Commercially available electromechanical prosthetic devices still lack touch-sensing capabilities, and there is a huge gap between research devices and commercially available ones. There is a need for small flexible touch sensors with high accuracy and sensitivity for this type of device. Touch sensors in prosthetic devices are needed for feedback mechanisms to the user and to achieve high dexterity in control schemes for fragile objects. A brief review of prosthetic touch sensors is presented, addressing desirable characteristics for touch sensing. In this paper, a custom shape flexible capacitive touch sensor is designed and characterized, meeting prosthetic sensors needs, such as thickness, power consumption, accuracy, repeatability, and stability. The designed sensor presented the capability to distinguish up to 0.5N steps with good stability. The sensor accomplished a full sensing range between 5N and 100N with reasonable accuracy, and hysteresis analysis achieved an average of 8.8 %. Clinical Relevance- The custom shape capacitive sensors proposed in this paper contribute to the development of tactile sensors for prosthetic devices as more accurate and sensitive sensor interfaces are required to detect and improve manipulating capabilities.

Effect of the Current Intensity and Inter-Electrode Distance in Surface Electrical Stimulation: A FEM Simulation Study.

In functional electric stimulation, variables such as electrode size, shape, and inter-electrodes distance can produce different neural and functional responses. In this work, a computational model combining FEM and MRG axon models is implemented to replicate two experimental studies that compare the effect of changing inter-electrode distance when applying FES to induce knee flexion. One work affirms that the stronger torque happens for greater distances, while the other obtain its maximum at lower distances. Using a simplified computational model gave another study perspective to understand why these two stimulation methodologies obtain different results. According to our results, an anodic stimulation occurs with greater current intensities and inter-electrode distances. This anodic effect can activate other nerve or motor points in the vicinity of the anode, explaining that more muscle fibers are recruited and generate an increased torque. Clinical Relevance - This work gives another view to understanding how the distance between electrodes affects neural activation, which has implications for optimizing clinical and exercise protocols using electrical stimulation techniques.

Embedded Electronic Sensor for Monitoring of Breathing Activity, Fitting and Filter Clogging in Reusable Industrial Respirators.

Millions of workers are required to wear reusable respirators in several industries worldwide. Reusable respirators include filters that protect workers against harmful dust, smoke, gases, and vapors. These hazards may cause cancer, lung impairment, and diseases. Respiratory protection is prone to failure or misuse, such as wearing respirators with filters out of service life and employees wearing respirators loosely. Currently, there are no commercial systems capable of reliably alerting of misuse of respiratory protective equipment during the workday shifts or provide early information about dangerous clogging levels of filters. This paper proposes a low energy and non-obtrusive functional building block with embedded electronics that enable breathing monitoring inside an industrial reusable respirator. The embedded electronic device collects multidimensional data from an integrated pressure, temperature, and relative humidity sensor inside a reusable industrial respirator in real time and sends it wirelessly to an external platform for further processing. Here, the calculation of instantaneous breathing rate and estimation of the filter's respirator fitting and clogging level is performed. The device was tested with ten healthy subjects in laboratory trials. The subjects were asked to wear industrial reusable respirator with the embedded electronic device attached inside. The signals measured with the system were compared with airflow signals measured with calibrated transducers for validation purposes. The correlation between the estimated breathing rates using pressure, temperature, and relative humidity with the reference signal (airflow) is 0.987, 0.988 and 0.989 respectively, showing that instantaneous breathing rate can be calculated accurately using the information from the embedded device. Moreover, respirator fitting (well-fitted or loose condition) and filter's clogging levels (≤60%, 80% and 100% clogging) also can be estimated using features extracted from absolute pressure measurements combined to statistical analysis ANOVA models. These experimental outputs represent promising results for further development of data-driven prediction models using machine learning techniques to determine filters end-of-service life. Furthermore, the proposed system would collect relevant data for real-time monitoring of workers' breathing conditions and respirator usage, helping to improve occupational safety and health in the workplace.

Autonomic nerve regulation in joint hypermobility patients with myofascial trigger points by Musculoskeletal Interfiber Counterirritant Stimulation (MICS).

Joint hypermobility (JH) conditions suggest dysfunction in the autonomic nervous system (ANS) (dysautonomia), associated with multifactor non-articular local musculoskeletal pain, and remains a complex treatment. This study aims to determine the effects of musculoskeletal interfiber counterirritant stimulation (MICS) as an innovative treatment of myofascial trigger points (MTrPs) on the upper trapezius muscle in JH patients. We evaluate the ANS activity by wavelet transform spectral analysis of heart rate variability (HRV) in sixty women, equally divided: MTrP, MTrP + general joint hypermobility (GJH), and MTrP + joint hypermobility syndrome (JHS). The protocol phases were rest, stimulation, and recovery, with clinical and home treatment for three-days. All groups show a significantly decreased in pain perception during and post-treatment, and an increased parasympathetic ANS activity under MICS in the GJH and JHS groups. The variables low-frequency (LF) vs. high-frequency (HF) showed significant differences during the protocol phases, and the LF/HF ratio maintained a predominance of sympathetic activity (SA) throughout the protocol. The new MICS technique reduces the pain perception and modulates the ANS activity by an increase in vagal tone, and a decrease in sympathetic tone. This modulation was followed by an increase in the HRV in JH patients after treatment with MICS. Clinical Trials: RBR-88z25c5.

Nitric oxide amplifies the rat electroretinogram.

It is well established that nitric oxide (NO) participates in retinal signal processing through stimulation of its receptor enzyme, soluble guanylyl cyclase (sGC). However, under pathological conditions such as uveoretinitis, diabetic or ischemic retinopathy, elevated NO concentrations may cause protein S-nitrosation and peroxynitrite formation in the retina, promoting cellular injury and apoptosis. Previous electroretinogram (ERG) studies demonstrated deleterious effects of NO on the retinal light response, but showed no evidence for a role in normal signal processing. To better understand the function of NO in ocular physiology, we investigated the effects of exogenous NO, produced by NO donors with different release kinetics, on the flash ERG of the rat. Within a limited concentration range, NO strongly amplified ERG a- and b-waves, oscillatory potentials, and the scotopic threshold response. Amplification exceeded 100% under dark adaptation, whereas the photopic ERG and the isolated cone response were increased by less than 50%. Blocking photoreceptor-bipolar cell synapses by AP-4 demonstrated a significant increase of the isolated a-wave by NO, and modeling the ERG generator PIII supported photoreceptors as primary NO targets. The sGC inhibitors ODQ and NS2028 did not reduce NO-dependent ERG amplification, ruling out an involvement of the classical NO effector cyclic GMP. Using immunohistochemistry, we show that illumination and exogenous NO altered the S-nitrosation level of the photoreceptor layer, suggesting that direct protein modifications caused by elevated levels of NO may be responsible for the observed phenomenon.

Step capacitive array sensor to trigger stimulation on Functional Electrical Stimulators devices for Drop Foot: Preliminary results.

In this work, a new custom wireless capacitive step sensor and a real-time algorithm are proposed to detect the start and end of the swing phase of the gait to trigger the stimulation in Functional Electrical Stimulator devices (FES) for Drop Foot. For this, an array of capacitive pressure sensors was designed to detect patterns of the gait swing phase through the Heel Center of Pressure (HCOP). The proposed system recognized all the events with an average error of 20.86±0.02[ms] for the heel strike (initial contact) and 27.60±0.03[ms] for the heel-off (final contact) compared with lower-back accelerometer, constituting a viable, robust and promising alternative as a step sensor for functional electrical stimulators.