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Background: Botulinum neurotoxin type A (BoNT‐A) is well‐established for treatment of glabellar lines (GLs), and mostly formulated as powders requiring reconstitution for injection. The approved liquid formulation, ready‐to‐use (RTU) abobotulinumtoxinA was developed to ease injection procedures and prevent reconstitution errors. This multicenter, open‐label, Phase IV study evaluated GL treatment experience using RTU abobotulinumtoxinA versus powder BoNT‐A (onabotulinumtoxinA). Methods: Females with experience of BoNT‐A facial treatment were randomized 2:1 to GL treatment with 50 U RTU abobotulinumtoxinA (N = 99) or 20 U powder BoNT‐A (N = 51) and followed‐up for 6 months or 1 month, respectively. Assessments included: time to prepare each product for injection (primary endpoint); investigators' experience with product preparation/reconstitution; investigators' and subjects' treatment experience; safety; and for the RTU product: aesthetic improvement of GLs; subject satisfaction. Results: Compared with powder BoNT‐A, RTU abobotulinumtoxinA required statistically significantly less preparation time (mean 0:33 vs. 1:34 min: s; p < 0.0001). Investigators preferred RTU abobotulinumtoxinA over powder BoNT‐A (81% of treatment sessions) and found it allowed more time to communicate with subjects (97%). All investigators (100%) also found it easy‐to‐use, easy‐to‐learn, and that it fulfilled their expectations. Subjects found the RTU abobotulinumtoxinA treatment comfortable (91%), and through 6 months posttreatment, most reported satisfaction with their appearance (≥88%), looking natural (≥95%) and refreshed (≥80%). At Month 1, 99% of RTU‐treated subjects had investigator‐assessed improved aesthetic appearance in GLs, maintained in 76% at Month 6. No serious adverse events occurred. Conclusion: RTU abobotulinumtoxinA for GL treatment is well‐tolerated, efficacious, shows high levels of subject satisfaction throughout 6 months, saves time, and is preferred by clinicians over powder BoNT‐A. ClinicalTrials.gov Registry: NCT05277337. [ABSTRACT FROM AUTHOR]

We present the first results of work towards a foil-based epiretinal prosthesis that can stimulate retinal cells. The prosthesis receives trigger signals and energy in the form of high intensity infrared radiation. Array-like silicon photodiodes with attached thin film electrodes convert the received infrared light into electrical stimulation signals, which are intended to stimulate ganglion cells. The photodiodes are arranged like stones in a mosaic on an only 10 µm thin and thus flexible polymer foil. Like this, the prosthesis can adapt to the curved shape of the eye and will have close contact with the retina.

This paper reports on the evaluation of recurrent and convolutional neural networks as real-time grasp phase classifiers for future control of neuroprostheses for people with high spinal cord injury. A field-programmable gate array has been chosen as an implementation platform due to its form factor and ability to perform parallel computations, which are specific for the selected neural networks. Three different phases of two grasp patterns and the additional open hand pattern were predicted by means of surface Electromyography (EMG) signals (i.e. Seven classes in total). Across seven healthy subjects, CNN (Convolutional Neural Networks) and RNN (Recurrent Neural Networks) had a mean accuracy of 85.23% with a standard deviation of 4.77% and 112 µs per prediction and 83.30% with a standard deviation of 4.36% and 40 µs per prediction, respectively.

The motility of the gastrointestinal tract is crucial for digestive activity and dysfunction can lead to severe disease pattern. A method for analysing the motility is needed when treatment approaches shall be evaluated. Therefore markers attached to different locations on the stomach and the bowel of pigs are video tracked in this research study. The markers are designed to provide a high contrast and have an adhesive side for fixation. Above the operation field a video camera has been placed to film the markers during the procedure. To analyse the video data a special algorithm has been implemented. The algorithm requires a registration process at the beginning of each recording which allows the parallel tracking of multiple markers. After the registration the algorithm tracks the position of the marker frame by frame. Each frame is converted into a greyscale picture by adding specified colour values of each pixel. This allows emphasizing certain colours. The centre of the marker is determined by computing the horizontal and vertical centre of the marker starting at the corresponding marker position of the previous frame. After completion the data is stored as coordinates and a video with the marker position displayed for further processing. For advanced analysis the data can be synchronized with electromyography signals, for example. The marked videos show a promising tracking of the markers. However, if the algorithm loses track of a marker during a recording, it is unlikely to relocate it due to the successive processing of the frames. Nevertheless this method provides a simple and easy to use solution for movement detection of the gastrointestinal tract.

This paper presents the design of implantable electronics as a part of a system for prosthetic hand control. Purpose of the implant is the sensing of electrical signals originating from biological tissue and the actuation of the same, therefore closing the loop and allowing for an improved control of the prosthetic hand. The implant contains two integrated circuits for eight channel EMG monitoring and four channel stimulation, respectively. An on-board microcontroller allows for local pre-processing. All intracorporeal to extracorporeal communications are running through and are directed by the main processing platform. The external components of the control system include, in addition to the main processing and control platform, the inductive power transfer circuits and the pressure sensors for the sensory feedback. Different assembly and encapsulation options are taken into account for the implantable electronics and are unified in a single PCB design.

Aspects and approaches for the design of systems for simultaneous signal and energy transmission for medical implants are presented. The main focus is on the consideration of the mutual influence on both transmission lines. To minimize the influence of capacitive as well as inductive paths, that affect the transmission, reducing the number of components is discussed. In order to increase the degree of miniaturization and reliability, the realization of certain functionalities is based on the so-called parasitics of electrical components. An implementation example is presented.

The usability of flexible electrodes in moving environment is limited due to different mechanical characteristics of their metallic and polymeric components. To achieve structure compatible electrodes, all used materials need to have similar Young’s moduli as the surrounding tissue. This paper describes the characterization of macroscopic as well as miniaturized electrodes entirely made out of modified silicone (PDMS). Electrochemical, mechanical, biological, optical, and applicative methods were used. It could be shown, that PDMS electrodes are capable to be used for recording electrocardiograms with similar form and amplitude as with standard electrodes.

Gastrointestinal (GI) motility disorders are frequent and clinically significant conditions with impairment of patient’s quality of life. Examples range from upper GI symptoms such as dysphagia and gastroparesis to lower GI manifestations, namely chronic-intestinal pseudo obstruction, diarrhea and constipation. Furthermore, postoperative motility disorders are common. Currently, available pharmacological or dietetic treatment options are limited. Since GI motility is based on myoelectric activity, electrical stimulation (ES) is a promising alternative. Numerous studies have demonstrated suitable pacing strategies and parameters in different GI segments. However, results of multilocular ES are rare. We report the first experimental study to evaluate ES of five GI parts in a porcine model. Multi-channel electromyography (EMG) recordings of gastrointestinal baseline and poststimulatory electrical activity were realized together with video-based marker tracking (VBMT). ES provoked visible GI contractions and appeared to modulate frequencies of slow waves and spikes. Further investigations are needed for analysis of locoregional and cross-organ effects of ES on the GI tract.

Two dimensional pelvic intraoperative neuromonitoring (pIONM®) is based on electric stimulation of autonomic nerves under observation of electromyography of internal anal sphincter (IAS) and manometry of urinary bladder. The method provides nerve identification and verification of its’ functional integrity. Currently pIONM® is gaining increased attention in times where preservation of function is becoming more and more important. Ongoing technical and methodological developments in experimental and clinical settings require further analysis of the obtained signals. This work describes a postprocessing algorithm for pIONM® signals, developed for automated analysis of huge amount of recorded data. The analysis routine includes a graphical representation of the recorded signals in the time and frequency domain, as well as a quantitative evaluation by means of features calculated from the time and frequency domain. The produced plots are summarized automatically in a PowerPoint presentation. The calculated features are filled into a standardized Excel-sheet, ready for statistical analysis.

In applied biomedical engineering and medical industry the transfer of established technology towards customers’ needs is essential for successful development and therefore business opportunities. In chronological order, we can show the transfer of scientific results of neurophysiological research into an existing neuromonitoring system and product which can be used by non-experts in medical technology in the operating room environment. All neurophysiology functions were realized in an intuitive graphical user interface. To stimulate the autonomous nerves, a specialized parameter paradigm was used, different from motor nerve stimulation. In the background, a complex signal processing algorithm recorded smooth muscle and bladder manometry data in synchronized time and automatically detected neurophysiological signals. The acquired data was then presented in real-time. With this effort a complex scientific task could be simplified to a Yes/No statement to the end-user. Beside all the reduction of complexity, the scientific challenge was still obtained, as raw-data is still possible to be recorded.

Finite element analysis (FEA) of electric current distribution in the pelvis minor may help to assess the usability of non-invasive surface stimulation for continuous pelvic intraoperative neuromonitoring. FEA requires generation of quality volumetric tetrahedral mesh geometry. This study proposes the generation of a suitable mesh based on MRI data. The resulting volumetric mesh models the autonomous nerve structures at risk during total mesorectal excision. The model also contains the bone, cartilage, fat, skin, muscle tissues of the pelvic region, and a set of electrodes for surface stimulation. The model is ready for finite element analysis of the discrete Maxwell’s equations.

In this publication the effect of the operating temperature on the effective inductance of a controllable inductor is analysed. The main difference compared to a coil with a simple single core lies in the current-controlled inductance-value. This is achieved by a second core implemented perpendicular upon the load-toroid affecting the saturation within a limited shared volume. Corresponding to the presented analysis, the dependencies on the core temperatures are investigated by measurements. [ABSTRACT FROM AUTHOR]

In this investigation, the flow simulation over different types of cavities (two- and three-dimensional) was performed. The effect of turbulence was implemented with detached-eddy simulation using the Spalart-Allmaras one-equation model. Initially, the flow behavior was investigated and compared for open and closed cavities. In the sound pressure level spectra of the closed cavity, only the broadband noise can be observed, while in the open-cavity case, it consisted of harmonic frequency peaks. Results of the two- and three-dimensional computations were compared with each other and with the available experimental data. It was observed that the results of three-dimensional simulations compared well with the experimental data, and the amplitude of the pressure fluctuations in the two-dimensional case was larger than in the three-dimensional model. Moreover, the pressure fluctuation of the two-dimensional cavity was more periodic than that of the three-dimensional case. Subsequently, a cavity with two circular openings on top, representing a landing gear housing, was investigated. Results show that the existence of these openings changes the characteristics of the flow inside the cavity, and the computed frequencies differ from the results calculated by the Rossiter semi-empirical formula. DOI: 10.2514/1.C000255

Numerical simulations of a turbulent flow over a backward-facing step are performed. The governing equations are solved by the finite volume code Cobalt. Unsteady three-dimensional detached eddy simulations are carried out with Menter's shear stress transport turbulence model acting as a subgrid-scale model. Mean flow quantities such as pressure, velocity, and skin-friction coefficients are accurately predicted. Velocity and pressure fluctuations are resolved by the three-dimensional computations. The dominant frequency is in good agreement with existing experimental data, and power spectral analysis of wall pressure fluctuation is consistent with empirical relations found in the literature for several operating conditions. DOI: 10.2514/1.43912

In addition to the two commonly used formulations for magnetofluid dynamics, a third formulation based on the decomposition of the magnetic field for solving full magnetofluid dynamics equations is explored. The governing equations are transformed to a generalized computational domain and discretized using a finite difference technique. A time-explicit multistage Runge--Kutta scheme augmented with total variation diminishing limiters for time integration is implemented. The developed codes have been validated with the existing closed-form solution of the magnetic Rayleigh problem. Results obtained from the decomposed magnetofluid dynamics equations compare well with results obtained by solving the classical full magnetofluid dynamics equations for a wide range of magnetic Reynolds numbers. It is shown that the decomposed magnetofluid dynamics technique requires substantially less computation time compared with classical full magnetofluid dynamics equations for the solution involving flowfields with high imposed magnetic fields. DOI: 10.2514/1.42626

In this paper, a new approach aimed at improving the performance of intraneural longitudinal interfaces (tf-LIFEs) with the peripheral nervous system (PNS) is presented. Our goal is to develop a movable interface by embedding microactuators into the flexible tf-LIFEs structure. In this way, the optimal position of the electrical contacts can be searched inside the PNS and lost connections with neural cells could be replaced. For this purpose a thin film of shape memory alloy (tf-SMA) was selected. A multisegmented SMA was realized and embedded between two polyimide thin films in order to simulate the tf-LIFE structure. Thermal evaluation, fabrication procedure, the first characterization and preliminary experimental results of the new movable interface are described in the manuscript. A total controllable stroke of about 10 [micro]m was obtained for the presented prototype. Index Terms--Biorobotics, intraneural interfaces, neuroprostheses, shape memory alloys, tf-LIFE.

High-speed flows over the surface of hypersonic airfoil subjected to several types of applied magnetic field distributions are numerically simulated. The governing equations are composed of the Euler equation modified to include the effect of magnetic field. In the current applications, the low magnetic Reynolds number approximation is utilized and the Hall effect and ion slip have been neglected. A fourth-order modified Runge-Kutta scheme augmented with the Davis--Yee symmetric Total Variation Diminishing model in post-processing stage is used to solve the magnetogasdynamics equations. The flow simulations are compared to the existing solutions. A good agreement between the present analysis and the available normal shock data is demonstrated. It has been found that the location and distribution of the imposed magnetic field have dominant effects on the flow parameters and the shock standoff distance. Index Terms--Fluid flow control, high-speed flows, magnetic fields, magnetohydrodynamics, numerical analysis.

Author(s): Bart Krekelberg (corresponding author) [1]; Sabine Dannenberg [2]; Klaus-Peter Hoffmann [2]; Frank Bremmer [2, 3]; John Ross [4] Current views of the visual system assume that the primate brain [...]