bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preadaptation of cell numbers for wound healing assays
Authors: Markhoff Jana , Brietzke Andreas , Grabow Niels 
Published: December 2021

Abstract
In vitro wound healing assays are a suitable application to verify the efficiency of pharmaceuticals or growth factors that will be incorporated in or immobilized to e.g. electrospun biomaterials for wound dressings or other biological devices in advance. Thereby, various factors like culture conditions or cell density influence the specific cell proliferation. Hence, to establish a wound healing assay for various cell types, a stepwise adaptation of cell numbers was done for better estimation and comparison of cell density for the validation of the influence of drugs on the wound healing process. Cell proliferation of different tissue relevant cell types was evaluated by impedance measurements and live cell imaging. Cell numbers could be successfully adapted for assay specific cell densities. In general, a universal comparison of biological or chemical materials and agents in vitro may require the creation of appropriate ISO or OECD standards for a consistent and cell specific adaptation or demand of initial cell density.
Development of an app-controlled simple, wearable teeth grinding sensing device
Authors: Eisenhardt Laura E. , Mayer Juliane , Pott Peter P. 
Published: December 2021

Abstract
Teeth grinding is, due to its various impacts on the human body, a highly discussed issue in dentistry. It can damage the tooth structure or cause pain due to muscle tension. At the moment, there is neither a satisfactory diagnostic nor a comprehensive treatment option. This paper deals with the development of an app-controlled, small, portable sensor unit that can be used by patients to monitor their teeth grinding in everyday life. It also offers a treatment option due to an implemented biofeedback option. To achieve the most cost-effective device possible, only off-the-shelf electronics and no proprietary software were used. In initial tests, the measuring device showed high level of measurement accuracy when performing measurements without feedback at rest (f_score=-0.025...0).
Dependence of SpO2 signal noise on the pulse oximeter averaging time
Authors: Rafl-Huttova Veronika , Hlavac Vit , Rafl Jakub , Rozanek Martin 
Published: December 2021

Abstract
A model of the pulse oximeter, which consists of a transfer function between arterial and peripheral blood oxygen saturation (SpO2) and the noise typical for SpO2 records, is an important part of a mathematical model of oxygenation in neonates that is designed to test and compare different algorithms of oxygen control. The noise level in the SpO2 signal is affected by the averaging time setting of the pulse oximeter. This study aimed to characterize the noise level in the SpO2 signal at the set pulse oximeter averaging times of 2- 4, 8, and 16 seconds. We evaluated SpO2 records of 17 healthy volunteers who underwent a laboratory experiment in which they evoked different types of artifacts. The noise level in the SpO2 signal was characterized by two parameters, the deviation of SpO2 from the true value and the SpO2 time stability, defined as the interval during which the measured SpO2 value remained unchanged. Statistical properties of the noise level for the three averaging times were represented by normalized histograms of both the parameters and varied according to the type of artifact. With motion artifacts, the SpO2 readings deviated from the true value by more than ±2% SpO2 in 10%, 7%, or 5% of the measurements when the set averaging time was 2-4 s, 8 s, or 16 s. The length of the interval over which the SpO2 value remained unchanged was most frequently 2 seconds for all set averaging times. Implementation of the noise characteristics into the computer model of oxygenation in neonates will allow more faithful simulations of the output SpO2 signal that better match clinical observations.
An interactive system for muscle and fat tissue identification of the lumbar spine using semantic segmentation
Authors: Bieck Richard , Baur David , Berger Johann , Stelzner Tim , Völker Anna , Neumann Juliane , Heyde Christoph-E. , Neumuth Thomas 
Published: December 2021

Abstract
We introduce a system that allows the immediate identification and inspection of fat and muscle structures around the lumbar spine as a means of orthopaedic diagnostics before surgical treatment. The system comprises a backend component that accepts MRI data from a web-based interactive frontend as REST requests. The MRI data is passed through a U-net model, fine-tuned on lumbar MRI images, to generate segmentation masks of fat and muscle areas. The result is sent back to the frontend that functions as an inspection tool. For the model training, 4000 MRI images from 108 patients were used in a k-fold cross-validation study with k = 10. The model training was performed over 25-30 epochs. We applied shift, scale, and rotation operations as well as elastic deformation and distortion functions for image augmentation and a combined objective function using Dice and Focal loss. The trained models reached a mean dice score of 0.83 and 0.52 and a mean area error tissue of 0.1 and 0.3 for muscle and fat tissue, respectively. The interactive webbased frontend as an inspection tool was evaluated by clinicians to be suitable for the exploration of patient data as well as the assessment of segmentation results. We developed a system that uses semantic segmentation to identify fat and muscle tissue areas in MRI images of the lumbar spine. Further improvements should focus on the segmentation accuracy of fat tissue, as it is a determining factor in surgical decisionmaking. To our knowledge, this is the first system that automatically provides semantic information of the respective lumbar tissues.
Hybrid test bench for high repetition rate radial shock wave measurement
Authors: Reinhardt Nina , Dick Theresa , Lang Laura , Radermacher Klaus , Fuente Matías de la 
Published: December 2021

Abstract
Radial shock wave therapy is used for different therapeutic indications. In order to assess the effect on the treated tissue, it is important to know the sound field parameters. However, it is challenging to measure the pressure curves of ballistic devices, especially at high pulse repetition rates. In the new standard IEC 63045:2020 two possibilities for sound field measurements of non-focusing devices are described, a wet and a dry test bench. The whole sound field can be characterised using a wet test bench, but the process is cumbersome and cavitation is likely to occur at high pulse repetition rates. This effect is avoided using a dry test bench where the measurement position is limited to a single spot. Therefore, a hybrid test bench was developed combining the dry bench’s device mounting and coupling with a small water basin. The ballistic device was coupled to the basin filled with degassed ultrapure water using a latex membrane covered with ultrasound gel and the contact pressure was applied with a spring. A fibre optic probe hydrophone was used for the sound field measurements. The pressure curves of every 10th shot were measured on the beam axis in a distance of 1mm to the membrane. The device was analysed at 3.5 bar with different pulse repetition rates (1 Hz, 10 Hz, 20 Hz). The test setup enables an easy handling and reproducible results at all pulse repetition rates. The ballistic device provides constant peak pressures over different frequencies. The small water basin has the advantage that the water quality is easy to control and the measuring process is fast and uncomplicated. Cavitation suppression requires a clean water basin filled with degassed ultrapure water kept at a constant, low temperature. The hybrid test bench can be used to easily study shock wave parameters of ballistic devices at high repetition rates.
TeleSDC
Authors: Pabst Tobias , Stegemann Dominik , Georgi Christoph , Kasparick Martin , Suleder Julian , Neumuth Thomas , Rockstroh Max 
Published: December 2021

Abstract
Telemedicine promises to increase the quality of emergency treatments. Besides the transfer of speech and video data, medical device and patient data will add additional value to the tele-guided emergency personnel. In this paper, we develop a concept for transmitting device and patient data via the open communication standards SDC in a telemedical context, including data transmission over mobile radio networks while considering the limitations of public networks, and opening new usage scenarios for telemedicine.
Field test of innovative digital technical assistance systems in the outpatient and inpatient care
Authors: Fischer Ulrich H. P. , Just Jens-Uwe , Haupt Matthias 
Published: December 2021

Abstract
The tecLA project developed a modular system for the area of Ambient Assisted Living (AAL) that enables older people to have simple, intuitive access to medical and technical assistance systems. A commercially available AAL application portal has been subjected to acceptance tests and optimizations and has proven itself in field tests. Furthermore, when comparing the self-assessment values to cognitive measures before and after the intervention, a clear trend towards more positive values in the post-test was recorded. It was also shown that the use of the system has very positive effects on communication behavior and cognitive selfassessment. The nurses and doctors can follow the vital signs online in the patient's file and evaluate them immediately.
Collaborative robot assisted smart needle placement
Authors: Neidhardt Maximilian , Gerlach Stefan , Laves Max-Heinrich , Latus Sarah , Stapper Carolin , Gromniak Martin , Schlaefer Alexander 
Published: December 2021

Abstract
Needles are key tools to realize minimally invasive interventions. Physicians commonly rely on subjectively perceived insertion forces at the distal end of the needle when advancing the needle tip to the desired target. However, detecting tissue transitions at the distal end of the needle is difficult since the sensed forces are dominated by shaft forces. Disentangling insertion forces has the potential to substantially improve needle placement accuracy.We propose a collaborative system for robotic needle insertion, relaying haptic information sensed directly at the needle tip to the physician by haptic feedback through a light weight robot. We integrate optical fibers into medical needles and use optical coherence tomography to image a moving surface at the tip of the needle. Using a convolutional neural network, we estimate forces acting on the needle tip from the optical coherence tomography data. We feed back forces estimated at the needle tip for real time haptic feedback and robot control. When inserting the needle at constant velocity, the force change estimated at the tip when penetrating tissue layers is up to 94% between deep tissue layers compared to the force change at the needle handle of 2.36 %. Collaborative needle insertion results in more sensible force change at tissue transitions with haptic feedback from the tip (49.79 ± 25.51)% compared to the conventional shaft feedback (15.17 ± 15.92) %. Tissue transitions are more prominent when utilizing forces estimated at the needle tip compared to the forces at the needle shaft, indicating that a more informed advancement of the needle is possible with our system.
Analysis of expansion within a pressure inflated section of an urethral stricture model
Authors: Bhave Ashish , Möller Knut 
Published: December 2021

Abstract
The Urethra is a long tubular structure in the genitourinary tract and serves important functions. Researchers have experimented with some approaches to model the urethra and to analyse its biomechanical properties. However, experiments to model the in-vivo behaviour of urethra with strictures is not thoroughly explored. To analyse the in-vivo urethral properties and specifically for supporting treatment of strictures, a new inflatable sensor-actuator system is being developed. The capabilities of this sensor shall be evaluated in simulations which require appropriate modelling of the human male urethra with strictures. This forms a part of the identification procedure for a variety of urethra conditions and geometries, which in turn forms a basis for inverse modelling. As an initial simplified approach, an axisymmetric Finite Element model was generated that resembled the urethra incorporating a stricture region. An ideal actuator with sensor elements exerting a pressure on inner wall of this urethra was simulated. Three circumference measurement zones within the sensor height (top surface, centre and bottom surface) were implemented. The resulting pressure-extension (circumferential) responses were determined at these measurement zones. The sensor was placed at different lengths within this urethral tube and inflated and the pressure-extension responses were noted. It was found that depending on the position of the sensor-actuator, the extension of tissue can vary. The possible factors for this variation were the finite length of the actuator as well as the influence of tissue properties around the measurement zones. This is important information for the interpretation of sensor data to be gained by the current development. It was possible to generate datasets based on an ideal sensor model, that proved helpful in the evaluation of biomechanical tissue properties in healthy and stricture conditions. This indicates simulations are a versatile and prospective way to test new sensors prior to real experiments.
Classification of Bundle Branch Blocks with QRS Templates Extracted from 12-lead ECGs
Authors: Welle Hannes , Nagel Claudia , Loewe Axel , Mikut Ralf , Dössel Olaf 
Published: December 2021

Abstract
Being non-invasive, cheap and widely available, the 12-lead electrocardiogram (ECG) is a standard method to assess cardiac function. Still, its reliable interpretation requires specialized knowledge and experience, rendering a second opinion valuable. We evaluated the performance of machine learning based classification of 11,705 healthy and bundle branch block 12-lead ECGs from 3 open databases. For each lead of the ECG signal, a representative QRS-complex template was extracted automatically. Principal component analysis (PCA) was applied to the concatenated, normalized and rescaled QRS signals to reduce their dimensionality. Multilayer perceptron and support-vector machine classifiers were trained using the principal components of weighted and non-weighted QRS template signals as input data. Classifiers achieved F1 scores between 0.92 and 0.96 on the test set for different input configurations. Anomaly based weighting slightly improved the performance of the classifiers. Neither class-wise PCA for feature extraction nor adding information on sex, gender and electrical heart axis to the input data yielded considerable improvement of the F1 scores. The achieved classification accuracy is similar to deep learning classifier performances and should generalize robustly to other ECG datasets. Our results suggest that this simple and well interpretable approach based on morphological signal characteristics is suitable for automatically and non-invasively identifying bundle branch block pathologies in clinical or smart electronics contexts.
In vitro biocompatibility testing of polymeric nanofiber scaffolds: fine-tuning for a better prediction of the in vivo behaviour
Authors: Khaimov Valeria , Klußmann-Fricke Bastian-Jesper , Illner Sabine , Siewert Stefan , Schmitz Klaus-Peter 
Published: December 2021

Abstract
Biomaterial research efforts focus on the development of biomaterials that mimic the natural extracellular environment. In addition, different strategies are applied to render materials for blood-contacting devices nonthrombogenic through surface modifications that would suppress activation of platelets, coagulation and the complement system. A confluent thin layer of endothelial cells lines all blood vessels and produces factors responsible for inhibition of coagulation, thrombosis and neointimal hyperplasia. Thus, the ability to rapidly form a healthy endothelium upon implantation represents a desired property of biomaterials used for cardiovascular devices. In this study we used advanced in vitro methods to investigate the biocompatibility of a biodegradable and a permanent electrospun nanofiber fabric, poly-L-lactic acid and polycarbonate-based silicone elastomer respectively, with the focus on endothelialization and hemocompatibility.
Universal single-board computer based control unit for biomedical test benches
Authors: Rhinow Grit , Tautorat Carsten , Grossmann Swen , Grabow Niels , Siewert Stefan , Schmitz Klaus-Peter , Schmidt Wolfram 
Published: December 2021

Abstract
Continuous adaptation of international standards for medical devices requires recurrent modification of test benches. A universal control unit using an open software environment is presented to simplify the maintenance of various test benches. Our developed control unit is equipped with a Raspberry Pi 4, with standard communication interfaces and application-specific electronic assemblies. The software is based on Node-RED, a browser-based editor. A measuring setup was adapted for a flow perfusion system. Our control unit simplifies the handling of the flow perfusion system by controlling a hydraulic pump and all required valves. A software programmed PID algorithm adapts the speed of the pump to adjust the pressure automatically. Actuators like proportional pinch valves are handled to control volumetric flow and pressure within the circulation. Consequently, the user directly observes changes inside the system. The measured data are stored and are available for documentation.
Quantitative evaluation of cell morphology and material interactions on opaque biomaterials
Authors: Klußmann-Fricke Bastian-J. , Reske Thomas , Schmitz Klaus-Peter , Siewert Stefan , Khaimov Valeria 
Published: December 2021

Abstract
One of the key aspects in the development of novel implants is to find suitable materials and understand the mechanisms that occur when a material is exposed to the tissues of the human body. These mechanisms are commonly referred to as the biocompatibility of the material. A better understanding of the tissue-material interactions becomes more urgent as biomaterials are used in wide-ranging applications like modern medical devices. However, most biomaterials used for implants are opaque, resulting in difficulties for the microscopical evaluation during in vitro biocompatibility testing. Particularly, cell morphology and adhesion capabilities of cells can provide insights in the interactions between implant materials and tissues at the implant site. To improve our capabilities in biocompatibility testing of novel biomaterials we applied a new method to quantitatively assess cellular parameters on opaque samples using fluorescence microscopy and bio-image analysis.
Definition of test parameters for dynamic mechanical testing of polymeric implant materials
Authors: Fiedler Nicklas , Arbeiter Daniela , Oschatz Stefan , Grabow Niels , Lebahn Kerstin 
Published: December 2021

Abstract
The selection of appropriate test conditions is of critical importance in mechanical testing of biomaterials. In particular the definition of dynamic test conditions is requiring high efforts. In this work, a thermoplastic semicrystalline polymer was characterized regarding mechanical properties by dynamic mechanical analysis (DMA). Timetemperature- superposition (TTS) of dynamic mechanical data provides an efficient method for the experimental design of follow-up studies. Our focus was to provide test conditions for cyclic tests, which correspond to viscoelastic materials. The results show, that the test temperature for dynamic mechanical fatigue tests, as an indicator of mechanical modification for viscoelastic materials, should necessarily remain below the onset temperatures of storage modulus and loss modulus. Moreover, changes in material characteristics due to varying frequencies should be considered when constructing a master curve for the evaluation of test frequencies. Therefore, TTS is particularly beneficial for the rapid determination of test parameters for accelerated material examination.
Electrospun coaxial hyaluronan-based fiber networks for ophthalmic drug release
Authors: Walter Torsten , Wyrwa Ralf , Altmann Cindy , Schnabelrauch Matthias 
Published: December 2021

Abstract
A micro-sized core-shell drug release device has been prepared by coaxial electrospinning based on a polylactide shell and the inner core phase made of high molecular weight hyaluronan or a cross-linked hyaluronan network. Timolol, which was inserted into the core phase, is widely used as drug for glaucoma treatment to depress the intraocular eye pressure and should be released over a longer time period from this fiber networks. Release studies of drug loaded fiber devices showed an only moderate burst release of timolol in the first days followed by a continuous longlasting drug release period over several weeks. With these findings, coaxial electrospinning represents a promising approach for the development of drug release systems with long-lasting, relatively constant drug delivery.
Functional Safety Concept EGAS for Medical Devices
Authors: Paulsen Benjamin Alexander , Henn Sandra , Männel Georg , Rostalski Philipp 
Published: December 2021

Abstract
For patient safety, it is important that a medical device can safely and reliably perform its intended purpose. The challenge in medical technology is that medical devices are heterogeneous systems and thus no widely applicable standard concepts for functional safety exist in medical technology. This is also reflected in the regulatory landscape, with its rather generally applicable standards. Patient safety is currently achieved by performing continuous risk management with an acceptable level of residual risk. Functional safety and its design concepts, as applied in other industries, have so far found little application in the field of medical technology. In this paper, the automotive safety concept "EGAS" is analyzed with regard to its applicability for medical devices. Based on the investigated example of a medical ventilator, important parallels were found between the automotive and the medical device sector, indicating the possibility of successfully applying the EGAS safety concept to medical devices.