bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of an embedded closed-loop stimulation current control principle based on the use of nonlinear ceramic capacitors
Authors: Olsommer Yves , Ihmig Frank R.
Published: December 2021

Over the years, a constant progress in the development of implantable medical devices (IMD’s) can be observed. On one hand, the advanced implantable electronics enable the implementation of numerous smart functionalities, on the other hand, the variety of electronic components including sensors and a bulky battery severely restrict their degree of miniaturization and reliability. To overcome this limitation, our approach is to realize smart functionalities in leadless and battery-free IMD’s emerging from frugal innovation by exploiting the intrinsic nonlinear properties of the components to be used anyway. The aim of this work is to deepen the understanding of the dynamic behavior of circuit topologies of nonlinear ferroelectric ceramic capacitors and to investigate their potential use for an embedded closed-loop control of the stimulation current. We characterized a selection of 40 commercial ceramic capacitors by measurement and simulation. The degree of nonlinearity resulting from a circuit topology consisting of one, two series and two parallel connected nonlinear capacitors was modeled and evaluated in Mathcad. We present a model with parameterized nonlinear capacitors to simulate the dynamic behavior of an inductively coupled implantable system. The stabilization and amplitude of the stimulation current is controlled by two features. These features are in turn controlled by the circuit topology and the degree of nonlinearity of the capacitors. We found that a high degree of nonlinearity allows the stimulation current to be stabilized within a reasonable range, but it makes the system more prone to instability. However, our model needs to include the dynamic behavior of ferroelectric materials used as dielectric in ceramic capacitors to extend the current investigations and to deepen the understanding of the physics behind the nonlinear properties of ferroelectric capacitors.
Virtual Therapeutics – Requirements to deliver value with virtual reality and biofeedback applications for alcohol addiction therapy
Authors: Hanshans Christian , Maisch Bettina , Zauner Johannes , Faust Moritz M. R. , Bröll Lukas M. , Karch Susanne
Published: December 2021

The application of virtual reality (VR) as a supportive tool in psychotherapy has gained great popularity in recent years. Especially for addiction therapy, a combination of virtual exposure and learning or training coping skills by using biofeedback has a high potential to improve conventional therapy. To add value, the new therapy system has to meet the needs of patients and practitioners likewise. Added values consistently named by experts included, but were not limited to, new possibilities of creating individual exposition or coping scenarios, enhanced psychoeducation, a shorter duration of treatment, telemedical aspects, the possibility of measuring and predicting craving and finally an improvement in abstinence. Besides literature research, we evaluated existing technical solutions in the field of virtual addiction treatment, surveyed experts and evolved a concept that led to a first prototype. The prototype consists of a wireless VR headset and a wireless multi-sensor system for measuring the physiological reaction to stimuli or the effectiveness of coping strategies by means of biofeedback. For further studies we developed both, a virtual exposure and a coping scenario and tested the hardware and software in a pilot study in order to elaborate factors that could negatively affect the therapy adherence, the effectiveness of exposition (immersion) and possible hurdles in practical use. Cybersickness and the lack of haptic feedback turned out to be the main limiting factors. Concepts for the next iteration of the therapy system will reflect these points for upcoming clinical studies. In our proof of concept, we demonstrated that virtual therapy can be implemented with a reasonable effort of time and costs. The combination of software and hardware, that supplements the traditional therapeutic approach, lays the foundation for upcoming clinical use and trials to prove the better outcome of VR enhanced addiction therapy.
A software for online monitoring of orientation-compensated forces during CI insertion
Authors: Schell Viktor , Böttcher Georg , Budde Leon , Zuniga M. Geraldine , Lenarz Thomas , Rau Thomas
Published: December 2021

The electrode array insertion is a critical point during CI surgery and should be performed as gently as possible to preserve residual hearing. In order to measure occurring forces, an insertion tool with an integrated force sensor and an inertial measurement unit (IM U) is being developed. The weight of the electrode holder and the sensor add an unknown offset to the measured forces, depending on the tool orientation. To address this problem, a software which calculates the orientation-induced error and computes a corrected force was developed. The software was written in C++ using the library Qt 5.12.9. For maximization of the computing frequency, the data acquisition of both sensors and the monitoring was parallelized. An algorithm was developed to calculate the error caused by the electrode holder and sensor. For this purpose both weights were determined in a calibration procedure and merged with the provided IM U data. The evaluation was done in two test series (each n=5) with different initial tool orientations. To this end a stepwise 360° rotation around the horizontal axis was performed, while recording the corrected forces. The developed software allows a computing frequency up to 100 Hz with a latency of 10 ms for the online monitoring of the processed data. The evaluation of the corrected force shows a residual error of 0.347 mN ± 0.325 mN for the first and 0.176 mN ± 1.971 mN for the second test series. With the created algorithm, the impact of the extra weight on the sensor can be almost fully equalized. The highly responsive software offers a new possibility to process insertion forces and provide feedback to surgeons. Determining the influence of the tool orientation on the corrected forces is the subject of future researches.
Illustrating orientation changes of the insertion trajectory during cochlear implant electrode array insertion
Authors: Zuniga M. Geraldine , Böttcher Georg , Schell Viktor , Lenarz Thomas , Rau Thomas S.
Published: December 2021

Introduction: Recent investigations focused on the optimization of atraumatic cochlear implant surgery have highlighted the relevance of the electrode array (EA) insertion trajectory. This is particularly studied in the context of minimally-invasive “keyhole” and robotic-assisted approaches, e.g. to avoid injuring structures inside and outside the cochlea. However, little is known about the natural, manual movements and trajectory followed during the insertion process. The present work illustrates the orientation changes within the trajectory a surgeon follows during insertions of EAs into a human cadaveric cochlea. Methods: An EA insertion tool equipped with a gyroscope was developed in our laboratory. During the insertion trials, the gyroscope captures the tool’s spatial orientation. A human head specimen and a single EA were used to perform insertions into a cochlea. A cochlear implant surgeon performed all insertion trials. The recorded orientations were compared to the initial orientation upon cochlea entry to assess the surgeon’s range of motion by calculating the angle between orientation vectors. Results: Fifteen EA insertions were performed with a median maximal deviation from the initial orientation of 7.2° (5.3 -11.1°) across trials. The largest orientation changes were seen towards the last half of each insertion trial. A negative relationship between degree of axis change and number of insertion trial was observed (r = -0.5). Conclusion: Manual EA insertions into a cadaveric cochlea revealed an insertion trajectory with maximum orientation changes of approximately < 10° degrees. The observed trend on decreasing range of motion with increasing number of insertion trials may be attributed to surgeon’s familiarization with the insertion trajectory for this specific specimen but other contributing factors (e.g. EA softening) need to be further elucidated with several EAs. Future evaluations can help determine if this orientation change is influenced by surgeon expertise.
On the development of a FHIR-compliant backend for processing HTTP requests and APIbased management of healthcare documents
Authors: Happel Rene , Larionov Pavel , Schanze Thomas
Published: December 2021

In palliative care, it is important to inform relatives or caring persons about the condition of the affected person, this could also include vital or biomedical data. Nonprofessional caregivers need information around the topic. However, the data should be stored in a backend system and be able to be viewed and edited by multiple caregivers on multiple platforms. Using the example of the backend solution described here, we will show how a FHIR-compliant server for health data, which could be provided from a digital health App (DiGA), can be established, as well as a second server for article database as a "CRUD"-API and user identification.
Separating atrial near fields and atrial far fields in simulated intra-atrial electrograms
Authors: Schicketanz Leonie , Unger Laura Anna , Sánchez Jorge , Dössel Olaf , Loewe Axel
Published: December 2021

The detailed characterization of complex forms of atrial flutter relies on the correct interpretation of intra-atrial electrograms. For this, the near field components, which represent the local electrical activity, are decisive. However, far field components arising from distant electrical sources in the atria can obscure the diagnosis. We developed a method to separate and characterize atrial near field and atrial far field components from bipolar intra-atrial electrograms. First, a set of bipolar electrograms was created by simulating different propagation scenarios representing common clinical depolarization patterns. Second, near and far fields were detected as active segments using a non-linear energy operator-based approach. Third, the maximum slope and the spectral power were extracted as features for all active segments. Active segments were grouped accounting for both the timing and the location of their occurrence. In a last step, the active segments were classified in near and far fields by comparing their feature values to a threshold. All active segments were detected correctly. On average, near fields showed 15.1x larger maximum slopes and 40.4x larger spectral powers above 100 Hz than far fields. For 135 active segments detected in 72 bipolar electrograms, 5.2% and 6.7% were misclassified using the maximum slope and the spectral power, respectively. All active segments were classified correctly if only one near field segment was assumed to occur per electrogram. The separation of atrial near and atrial far fields was successfully developed and applied to in silico electrograms. These investigations provide a promising basis for a future clinical study to ultimately facilitate the precise clinical diagnosis of atrial flutter.
Evaluation and Implementation of Biocompatible Methods for the Cross-linking of Plasma Proteins
Authors: Bode Tom , Höltje Kai , Leal-Marin Sara , Müller Marc , Glasmacher Birgit
Published: December 2021

Autologous plasma proteins can be used to fabricate patient specific cardiovascular implants but need to be cross-linked to increase their mechanical strength and reduce water solubility. Glutaraldehyde is the state-of-the-art solution but its reaction products have been shown to be cytotoxic and pro-inflammatory. In this work, it has been shown, that cross-linking of plasma proteins with biocompatible alternatives to glutaraldehyde is possible. This was achieved by identifying four candidate substances (thrombin, transglutaminase, genipin, EDC) from current literature and investigating their ability to cross-link porcine plasma proteins in vitro. The degree of crosslinking was examined using calorimetric (DSC) and spectroscopic (FTIR, Raman) methods, mapping the influence of cross-linking on the denaturation temperature and primary amino-group content of the proteins. It could be shown that thrombin, genipin and EDC are able to cross-link plasma proteins to a satisfactory degree and thus represent useful alternatives to glutaraldehyde. Transglutaminase, on the other hand, could not sufficiently cross-link the plasma proteins and was therefore ruled out as an alternative.
Using a micro-physiological system to prolong the preservation of ex vivo lung tissue
Authors: Böhlen Sebastian , Konzok Sebastian , Labisch Jennifer , Dehmel Susann , Schaudien Dirk , Behrens Stephan , Schmieder Florian , Braun Armin , Sonntag Frank , Sewald Katherina
Published: December 2021

Current in vitro and in vivo disease models have been reported to lack sufficient translation to human. Precision-Cut Lung Slices (PCLS) are viable sections of lung tissue and have been described to be a translational model for the ex vivo assessment of pharmacological and toxicological compounds. In most studies PCLS were cultured under static conditions. These lung sections, however, suffer from the limited viability. Here we present a novel modular microphysiological system (MPS) to prolong the cultivation of ex vivo lung tissue. A tailored MPS setup was designed using the PDMS free modular plug&play MPS construction kit. PCLS from mice were cultivated for up to one week under static versus perfused conditions. Using the MPS technology enabled a prolonged culture period with improved viability as shown by lowered lactate dehydrogenase release and improved membrane integrity. Using this technology might allow us to use PCLS for longer culture periods such as e.g. repeated dose toxicity or pharmacology studies.
Reducing dose of Cone-Beam CT used for patient positioning in radiooncology
Authors: Gorges Verena , Zylka Waldemar
Published: December 2021

Cone-Beam computed tomography (CBCT) has become the most important component of modern radiotherapy for positioning tumor patients directly before treatment. In this work we investigate alternations to standard acquisition protocol, called preset, for patients with a tumor in the thoracic region. The effects of the changed acquisition parameters on the image quality are evaluated using the Catphan Phantom and the image analysis software Smári. The weighted CT dose index (CTDIW) is determined in each case and the effects of the different acquisition protocols on the patient dose are classified accordingly. Additionally, the clinical suitability of alternative presets is tested by investigating correctness of image registration using the CIRS thorax phantom. The results show that a significant dose reduction can be achieved. It can be reduced by 51% for a full rotation by adjusting the gantry speed. A more patientspecific uptake protocol for patients with laterally located tumor was created which allows a dose reduction of 54%.
Design and implementation of a medical device test stand for micro-catheters and guide-wires
Authors: Klink Fabian , Boese Axel , Voß Samuel , Beyer Christiane
Published: December 2021

The use of catheters and guide-wires in minimally invasive therapeutic approaches is an important part of clinical practice. In the neurovascular field, the unique nature of cerebral blood vessels necessitates very thin-walled and flexible catheters. The blood vessels in question are highly branched and at the same time can be less than one millimetre in diameter. This results in high demands on micro-catheters and guide-wires for successful endovascular therapy. The interaction of these surgical tools and the vessel wall is of especial interest. Depending on the catheter stiffness, this interaction can be friction, punctual collision or straightening. The work aims to design and implement a test setup for evaluation of these interactions with the vessel wall. For this purpose, a standardized vessel course with representative characteristics is necessary. Furthermore, by implementing suitable measuring equipment, an endovascular intervention can be simulated.
Self-Assembling Flexible 3D-MEAs for Cortical Implants
Authors: Hegel Lena , Kauth Andrea , Seidl Karsten , Ingebrandt Sven
Published: December 2021

Flexible Multi Electrode Arrays (MEAs) for neural interfacing reduce the mechanical mismatch between the soft brain tissue and the electrode arrays allowing accurate signal recordings and neural stimulation while reducing inflammatory responses. Many standard manufacturing processes of MEAs are designed for planar structures and the production of three-dimensional structures is challenging. In the present study, shaft structures with one to two circular gold microelectrodes (10 - 20 μm), each on a base polyimide (PI) substrate, were investigated. We describe a fabrication method, with which shafts made from bi-layer PI flip into the third dimension, which is a first step towards spontaneous assembly of electrodes in flexible 3D MEAs for neuroelectronic applications. A lift-up of the shafts was achieved by the contraction of a second PI layer and a steady nitrogen flow during polycondensation. This shrinking PI was structured in pits with a width of 5 - 600 μm. We achieved liftup angles of up to 42 degrees. The shaft structures can be hardened and later be used for neural implantation experiments.
3D Printed Individualized Frontal Neo-Ostium Implant in Endoscopic Sinus Surgery – a Proof of Concept Study
Authors: Gao Ziwen , Matin Farnaz , Wei Chunjiang , Lenarz Thomas , Weber Constantin , John Samuel , Scheper Verena
Published: December 2021

3D-printing paves the way for personalized drug therapy via implants individualized for the patient specific anatomy in chronic paranasal sinus diseases. This study brings together the workflow of modeling, manufacturing, and sterilization of 3D-printed individualized frontal neo-ostium implants (FOI) for optimization of Endoscopic Sinus Surgery (ESS) and validates the implantability of the printed devices. The study sample consisted of six adult human cadavers. Digital volume tomography (DVT) images were taken before and after ESS. The FOI models were based on the post-ESS anatomy. The area to be implanted was analysed in the preand post-ESS DVT images for volume and surface area. A specialized surgeon in rhinology judged the implantability of the 3D-printed FOI. The mean values of volume and surface area tended to be larger in the post-operation situs than in preoperation DVT images and we are therefore not yet convinced that pre-operation images will reflect the correct anatomy for the personalization of the FOI. The workflow of manufacturing and implantation of individualized 3D-printed sterile FOI is established but future studies are needed for further improvement.
Pulse Arrival Time - A Sensitive Vital Parameter for the Detection of Mental Stress
Authors: Ernst Hannes , Scherpf Matthieu , Malberg Hagen , Schmidt Martin
Published: December 2021

Mental stress triggers positive inotropic and chronotropic effects as well as peripheral vasoconstriction. This alters the pulse arrival time (PAT), the duration between electrical excitation of the ventricles and arrival of the pulse wave in the periphery. We conducted a study to examine PAT during five rest blocks and under mental stress utilizing the Mannheim Multicomponent Stress Test. Electrocardiograms as well as finger and earlobe photoplethysmograms were recorded. PAT was calculated for over 135,000 heartbeats from 42 healthy volunteers as the time duration between the R peak in the electrocardiogram and the following pulse onset in the respective photoplethysmogram. To identify the effect of mental stress, block-wise PAT means were statistically analyzed with repeated measures ANOVA. The analyses showed significant differences between the block means for both PAT measures (p < 0.001). Post-hoc tests revealed significantly reduced PAT during the stress block compared to all rest blocks for both PAT measures (p < 0.001). We found no significant differences between the rest blocks. Our results support that PAT is a sensitive vital parameter for the detection of mental stress in healthy volunteers. This holds true for both measurement positions, the finger and the earlobe.
Near-UV to Near-IR Multispectral Illumination in a Digital Surgical Microscope
Authors: Wisotzky Eric L. , Uecker Florian C. , Rosenthal Jean-Claude , Arens Philipp , Schneider Armin
Published: December 2021

We present a stereo-multispectral microscope equipped with an additional illumination unit allowing further narrow-band illumination in the spectral range of 400n.m up to 800nm. The combination of the normal microscope illumination with the multispectral light unit allows different illumination modalities to be realized, which enables intraoperative spectral tissue analysis with direct visualization. Two illumination methods were tested in two cholesteatoma surgeries. In addition, two cholesteatom samples were illuminated and analyzed ex vivo. Cholesteatoma showed :fluorescent characteristics in our ex vivo analysis. This behavior could be used intraoperatively using a combination of white light and strong near-UV to blue illumination to highlight cholesteatoma tissue in the microscopic image. Thus, the visual differentiability of different tissue types can be improved and the clinical decision-making process can be accelerated.
Assessing Generalisation Capabilities of CNN Models for Surgical Tool Classification
Authors: Alshirbaji Tamer Abdulbaki , Jalal Nour Aldeen , Docherty Paul D. , Neumuth Thomas , Moeller Knut
Published: December 2021

Accurate recognition of surgical tools is a crucial component in the development of robust, context-aware systems. Recently, deep learning methods have been increasingly adopted to analyse laparoscopic videos. Existing work mainly leverages the ability of convolutional neural networks (CNNs) to model visual information of laparoscopic images. However, the performance was evaluated only on data belonging to the same dataset used for training. A more comprehensive evaluation of CNN performance on data from other datasets can provide a more rigorous assessment of the approaches. In this work, we investigate the generalisation capability of different CNN architectures to classify surgical tools in laparoscopic images recorded at different institutions. This research highlights the need to determine the effect of using data from different surgical sites on CNN generalisability. Experimental results imply that training a CNN model using data from multiple sites improves generalisability to new surgical locations.
Development of Bioimpedance Sensors and Measurement System for Biomedical In-Vitro Applications
Authors: Sebastian Stadler B. Eng. , Plischke Herbert , Hanshans Christian
Published: December 2021

Bioimpedance analysis is a label-free and easy approach to obtain information on cellular barrier integrity and cell viability more broadly. In this work, we introduce a small, low-cost, portable in vitro impedance measurement system for studies where a shadow-free exposure of the cells is a requirement. It can be controlled by a user-friendly web interface and can perform measurements automated and autonomously at short intervals. The system can be integrated into an existing IoT network for remote monitoring and indepth analyses. A single-board computer (SBC) serves as the central unit, to control, analyze, store and forward the measurement data from the single-chip impedance analyzer. Various materials and manufacturing methods were used to produce a purpose-built lid on top of a modified 24-well microtiter plate in a “do it yourself” fashion. Furthermore, three different sensor designs were developed utilizing anodic aluminum oxide (AAO) membranes and gold-plated electrodes. Preliminary tests with potassium chloride (KCl) showed first promising results.
Antimicrobial Activity in the Gasphase with Hypochloric Acid
Authors: Boecker Dirk , Breves Roland , Zhang Zhentian , Bulitta Clemens
Published: December 2021

Background:The study investigated if the disinfecting potential of Hypochlorous acid (HOCl) in suspensions are transferrable to in-air cleaning applications and to what extent aerosolized HOCl solutions can deactivate indoor microbial contaminations in-air at or below legal limits. Material and Method: For the liquid disinfection we used a standard suspension disinfection test protocol. For the in-air tests we conducted several experiments where aerosolized bacterial suspensions were injected into lab chambers preloaded with different HOCl gas concentrations. Results:In suspension experiments we found sufficient efficacies for all studied organisms at minimum concentrations of 200 ppm HOCl. The in-air measurement set-up allows to follow microbe deactivation by HOCl interaction. The deactivation rate increases with the HOCl concentration, and the values are highest for Gram-negative bacteria. Conclusion:We confirmed our hypothesis of the high disinfecting power of HOCl in-air at safe levels for populated indoor places. The investigated bacteria provide a model system for infectious particles, including enveloped viruses (to which Coronavirus belongs). These early results suggest that HOCl should be further evaluated as an air-cleaning method which may complement established concepts.
Acquisition of Semantics for AI-based Applications in Medical Technologies
Authors: Wittenberg Thomas , Benz Michaela , Foltyn Andreas , Hackner Ralf , Hetzel Julia , Wiesmann Veit , Eixelberger Thomas
Published: December 2021

For the development, training, and validation of AIbased procedures, such as the analysis of clinical data, prediction of critical events, or planning of healthcare procedures, a lot of data is needed. In addition to this data of any origin (image data, bio-signals, health records, machine states, …) adequate supplementary information about the meaning encoded in the data is required. With this additional information - the semantic or knowledge - a tight relation between the raw data and the human-understandable concepts from the real world can be established. Nevertheless, as the amount of data needed to develop robust AI-based methods is strongly increasing, the assessment and acquisition of the related knowledge becomes more and more challenging. Within this work, an overview of currently available concepts of knowledge acquisition are described and evaluated. Four main groups of knowledge acquisition related to AI-based technologies have been identified. For image data mainly iconic annotation methods are used, where experienced users mark or draw depicted entities in the images and label them using predefined sets of classifications. Similarly, bio-signals are manually labelled, whereby important events along the timeline are marked. If no sufficient data is available, augmentation and simulation techniques are applied yielding data and semantics at the same time. In applications, where expensive sensors are replaced by low-cost devices, the high-grade data can be used as semantics. Finally, classic rule-based approaches are used, where human factual and procedural knowledge about the data and its context is translated into machine-understandable procedures. All these methods are depending on the involvement of human experts. To reduce this, more intelligent and hybrid approaches are needed, shifting the focus from the-human-in-the-loop to the-machine- in-the-loop.
Service-Oriented Medical Device Connectivity: Particular Interoperability Standards for High Frequency Surgical Equipment and External Control Devices
Authors: Kasparick Martin , Köny Marcus , Andersen Björn , Riech Kathrin , Keller Anton , Kämmer Sven , Guth Andreas , Mündermann Lars , Stickel Axel , Klöckner Stephan , Golatowski Frank , Timmermann Dirk
Published: December 2021

Manufacturer-independent medical device interoperability has been strongly demanded by the clinicians and healthcare delivery organizations (HDOs), however has not been achieved in practice for decades. The ISO/IEEE 11073 Service-oriented Device Connectivity (SDC) family of standards constitutes a paradigm shift. This work supplements SDC with Device Specializations (DevSpecs) or Modular Specifications (ModSpecs): particular interoperability standards for high frequency (HF) surgical equipment and external control devices, such as foot or finger switches. They provide models to describe these devices in a service-oriented medical device system and modes of interaction with other network participants. Additionally, we contribute to the ISO/IEEE 11073-10101 nomenclature standard to provide semantic descriptions of the exchanged information. This is a key enabler for safe and effective medical device interoperability to support the caregivers and improve patient safety as well as clinical outcome.
Plasma Enhanced Atomic Layer Deposition of Iridium Oxide for Application in Miniaturized Neural Implants
Authors: Simon Nicolai , Asplund Maria , Stieglitz Thomas , Bucher Volker
Published: December 2021

High quality recording of neuronal activities and electrical stimulation require neurotechnical implants with appropriate electrode material. Iridium oxide (IrOx) is an excellent choice of material due to its biocompatibility, low electrochemical impedance, superior charge injection capacity, corrosion resistance, longevity, and electrochemical stability. Plasma enhanced atomic layer deposition (PE-ALD) and a suitable precursor, like (Methylcyclopentadienyl) (1,5- cyclooctadiene) iridium, could be a promising technique to produce highly conformal and performant IrOx-films at low temperatures and low costs. Various studies have reported the deposition of iridium oxide, but usually at very high temperatures. These processes are not suitable for polymer substrates and limit the use of such post-processing together with active implants. In this work the (Methylcyclopentadienyl) (1,5-cyclooctadiene) iridium(I) ((MeCp)Ir(COD)) precursor was used as a promising approach for depositing IrOx-films using low temperature PE-ALD. This precursor is normally used for chemical vapour deposition processes. First experiments were carried out on silicon substrates at deposition temperatures of 110 C°. The precursor was heated up to 75 °C and oxygen plasma was used as coreactant. The deposited films were analysed with EDX and AFM, showing a smooth surface and a promising ratio between the elements iridium and oxygen.
Ultrasound Thermometry for HIFU-Therapy
Authors: Daschner Rosa , Hewener Holger , Bost Wolfgang , Weber Steffen , Tretbar Steffen , Fournelle Marc
Published: December 2021

High-Intensity Focused Ultrasound (HIFU) is an alternative tumour therapy with the ability for non-invasive thermal ablation of tissue. For a safe application, the heat deposition needs to be monitored over time, which is currently done with Magnetic Resonance Imaging. Ultrasound (US) based monitoring is a promising alternative, as it is less expensive and allows the use of a single device for both therapy and monitoring. In this work, a method for spatial and temporal US thermometry has been investigated based on simulation studies and in-vitro measurements. The chosen approach is based on the approximately linear dependence between temperature and speed of sound (SoS) in tissue for a given temperature range. By tracking the speckles of successive B-images, the possibility of detecting local changes in SoS and therefore in temperature is given. A speckle tracking algorithm was implemented for 2D and 3D US thermometry using a spatial compounding method to reduce artifacts. The algorithm was experimentally validated in an agar-based phantom and in porcine tissue for temperature rises up to △ 8°C. We used a focusing single element US transducer as therapeutic probe, a linear (/matrix array) transducer with 128 (/32∙32) elements for imaging and thermocouples for validation and calibration. In all experiments, both computational and in-vitro, we succeeded in monitoring the thermal induced SoS changes over time. The in-vitro measurements were in good agreement with the simulation results and the thermocouple measurements (rms temperature difference = 0.53 °C, rms correlation coefficient = 0. 96).
Health Software Product or Software as Medical Device
Authors: Lukas Tabea , Sohrabi Keywan , Gross Volker , Scholtes Michael
Published: December 2021

The number of software products in the field of health and medicine increases excessively. Self-tracking, fitness, health advice, dose calculation, and analysis of physiological data - apps are popular and commonly used. Some of the products are affected by the medical device regulation, consciously or unconsciously. For young entrepreneurs, it is difficult to recognize and understand the distinction between software as medical product and health software products. A product-related orientation guide could help start-ups to understand the difference and to find the right strategy for placing their product on the market. All relevant information were collected and analyzed. Input came from a systematic literature research, an evaluation of the CHARISMHA study and a consideration of the medical device regulation as well as the relevant standards (e.g. IEC 62304 and IEC 82304). The guide was adapted to the particular situation of start-ups and microenterprises, inter alia having regard to missing regulatory affairs competences. A product-related orientation guide for young entrepreneurs was developed, which helps to identify whether products are affected by the medical device regulation or not. The guide uses a few simple questions, and it allows the entrepreneurs to estimate the related effort. Furthermore, it provides an overview of relevant standards and needed competences for the chosen path. The guide brings certainty and can help young entrepreneurs to identify the upcoming workload at an early stage. Due to the decision tree concept, it is easy to adapt the product-related strategy and see the consequences. This might help entrepreneurs to find the right strategy for placing their product on the market. Nevertheless, field testing with the guide is necessary to validate its benefit.
Nonlinearity of Magnetostrictive Torque Sensor under Varying External Magnetic Field Strength
Authors: Wilkie Jack A. , Moeller Knut
Published: December 2021

Correctly torquing bone screws is an important factor in achieving positive patient outcomes during orthopaedic surgery. A torque-limiting smart screwdriver concept has been proposed, and ongoing work is being undertaken to model the screwing process and allow the concept to work. These models require experimental validation, so a test rig was developed. The magnetostrictive torque sensor in this test rig was affected by magnetic parts of the test rig, which offset the zero-torque point; this raised concerns over the effects on linearity, which were tested here. The torque sensor was tested against a non-magnetostrictive reference under varying external magnetic conditions. While the magnetic field offset the torque, there was no notable change in linearity under the conditions tested, and the linearity was always within the datasheet specifications. Hence, we conclude that in the context of this test rig, there were no negative effects on linearity, although under higher loading or stronger magnetic conditions, this may not hold.
EEG based emotion recognition using entropy features and Bayesian optimized random forest
Authors: Kumar Himanshu , Ganapathy Nagarajan , Puthankattil Subha D. , Swaminathan Ramakrishnan
Published: December 2021

Electroencephalography (EEG) based emotion recognition is a widely preferred technique due to its noninvasiveness. Also, frontal region-specific EEG signals have been associated with emotional processing. Feature reductionbased optimized machine learning methods can improve the automated analysis of frontal EEG signals. In this work, an attempt is made to classify emotional states using entropybased features and Bayesian optimized random forest. For this, the EEG signals of prefrontal and frontal regions (Fp1, Fp2, Fz, F3, and F4) are obtained from an online public database. The signals are decomposed into five frequency bands, namely delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (14-30 Hz), and gamma (30-45 Hz). Three entropy features, namely Dispersion Entropy (DE), Sample Entropy (SE), and Permutation Entropy (PE), are extracted and are dimensionally reduced using Principal Component Analysis (PCA). Further, the reduced features are applied to the Bayesian optimized random forest for the classification. The results show that the DE in the gamma band and SE in the alpha band exhibit a statistically significant (p < 0.05) difference for classifying arousal and valence emotional states. The selected features from PCA yield an F-measure of 73.24% for arousal and 46.98% for valence emotional states. Further, the combination of all features yields a higher F-measure of 48.13% for valence emotional states. The proposed method is capable of handling multicomponent variations of frontal region-specific EEG signals. Particularly the combination of selected features could be useful to characterize arousal and valence emotional states.
eVision: Epidemic Forecasting on COVID-19
Authors: Shaghaghi Navid , Calle Andres , Kouretas George , Mirchandani Jaidev , Castillo Michael
Published: December 2021

Vaccination is the primary strategy to prevent COVID-19 illness and hospitalization. However, supplies are scarce and due to the regional mutations of the virus, new vaccines or booster shots will need to be administered potentially regularly. Hence, the prediction of the rate of growth of COVID-19 cases is paramount to ensuring the ample supply of vaccines as well as for local, state, and federal government measures to ensure the availability of hospital beds, supplies, and staff. eVision is an epidemic forecaster aimed at combining Machine Learning (ML) - in the form of a Long Short-Term Memory (LSTM) Recursive Neural Network (RNN) - and search engine statistics, in order to make accurate predictions about the weekly number of cases for highly communicable diseases. By providing eVision with the relative popularity of carefully selected keywords searched via Google along with the number of positive cases reported from the US Centers for Disease Control and Prevention (CDC) and/or the World Health Organization (WHO) the model can make highly accurate predictions about the trend of the outbreak by learning the relationship between the two trends. Thus, in order to predict the trend of the outbreak in a specific region, eVision is provided with a weekly count of the number of COVID-19 cases in a region along with statistics surrounding common symptom search phrases such as “loss of smell” and “loss of taste” that have been searched on Google in that region since the start of the pandemic. eVision has, for instance, been able to achieve an accuracy of %89 for predicting the trend of the COVID-19 outbreak in the United States
Evaluation of Streptococcus oralis adhesion and biofilm formation on laser-processed titanium
Authors: Doll Katharina , Veiko Vadim , Karlagina Yulia , Odintsova Galina , Heine Nils , Egorova Elena , Radaev Maxim , Chichkov Boris , Stiesch Meike
Published: December 2021

To prevent implant-associated infections, surface modifications need to be developed that prevent bacterial colonisation and biofilm formation. In the present study, titanium surfaces were processed by nanosecond-pulsed laser ablation to generate a variety of different structures (anatase, rutile, Osteon, as well as Osteon additionally coated with silver and clove nanoparticles). Analysis of adhesion and biofilm formation of the oral pioneer bacterium Streptococcus oralis could demonstrate antibacterial properties of anatase surfaces. For clinical translation, the effect should be enhanced by further adaption and combined with the osseointegrative Osteon structure
Curriculum Innovation in Language Teacher Education: Reflections on the PGDELT Program’s Contributions to EFL Teachers’ Continuing Professional Development
Authors: Zhang Lawrence Jun
Published: December 2021

Initial teacher preparation and teachers’ continuing professional development are two significant pillars of the teacher education enterprise. The former encompasses a wide range of teacher-education initiatives at the levels of diploma, bachelor’s degree, postgraduate diploma, and even master’s degree for teacher licensure purposes. These are widely documented in the literature. What is important is how teacher professional development contributes to bolstering the teacher-educator force, which is relatively insufficiently documented due to the very fact that different educational systems have somewhat different expectations of such programs in relation to the ideologies and theories underpinning the teacher professional development program design and curriculum offering. Taking stock of a postgraduate diploma program in English language teaching (PGDELT) for teachers’ continuing professional development with a 31-year history housed at a premier teacher education institution in Singapore, which has successfully graduated over 1, 000 English language teachers for colleges and universities in China, I intend to highlight some of its key features, as a former student and then a lecturer on the program, in order to draw implications for sustainable growth of language teacher education programs, especially those whose main purposes are to prepare teachers of English as a second or foreign language (ESL/EFL) and provide continuing professional development opportunities for such inservice teachers.
“Sick or not sick?” A mixed methods study evaluating the rapid determination of illness severity in a pediatric emergency department
Authors: O’Neill Laura B. , Bhansali Priti , Bost James E. , Chamberlain James M. , Ottolini Mary C.
Published: December 2021

Objectives

Experienced physicians must rapidly identify ill pediatric patients. We evaluated the ability of an illness rating score (IRS) to predict admission to a pediatric hospital and explored the underlying clinical reasoning of the gestalt assessment of illness.

Methods

We used mixed-methods to study pediatric emergency medicine physicians at an academic children’s hospital emergency department (ED). Physicians rated patients’ illness severity with the IRS, anchored by 0 (totally well) and 10 (critically ill), and shared their rationale with concurrent think-aloud responses. The association between IRS and need for hospitalization, respiratory support, parenteral antibiotics, and resuscitative intravenous (IV) fluids were analyzed with mixed effects linear regression. Area under the curve (AUC) receiver operator characteristic (ROC) curve and test characteristics at different cut-points were calculated for IRS as a predictor of admission. Think-aloud responses were qualitatively analyzed via inductive process.

Results

A total of 141 IRS were analyzed (mean 3.56, SD 2.30, range 0–9). Mean IRS were significantly higher for patients requiring admission (4.32 vs. 3.13, p<0.001), respiratory support (6.15 vs. 3.98, p = 0.033), IV fluids (4.53 vs. 3.14, p < 0.001), and parenteral antibiotics (4.68 vs. 3.32, p = 0.009). AUC for IRS as a predictor of admission was 0.635 (95% CI: 0.534–0.737). Analysis of 95 think-aloud responses yielded eight categories that describe the underlying clinical reasoning.

Conclusions

Rapid assessments as captured by the IRS differentiated pediatric patients who required admission and medical interventions. Think-aloud responses for the rationale for rapid assessments may form the basis for teaching the skill of identifying ill pediatric patients.
Dao ist das Gegenteil Gottes
Authors: Ziporyn Brook
Published: December 2021

The term Dao originally means a Way or Course or Guide, something very close to purposive action as such – a prescribed course to attain a prescribed goal. It is precisely something that is selected out, valued, desired, kept to rather than discarded. The Daoist usage of the term “Dao” is thus an ironic usage: it is used deliberately in the opposite of its literal sense to make a point – the real way to attain value is through what we do not value, the real way is an anti-way, the real fulfilment of purpose lies in letting go of purpose. Purpose by definition excludes the purposeless. But this relationship is not symmetrical; purposelessness does not exclude purpose. On the contrary, it includes, allows, and even generates purpose. Not one purpose, however, but infinite purposes, all of which remain embedded in a larger purposelessness, but not contradicted or undermined by it. The structure of purpose is such as to either exclude or to subordinate the purposeless. But even if merely subordinated rather than excluded, purposelessness ceases tobe genuinely purposeless. It becomes instead instrumental to purpose, pervaded completely by purpose. So a monotheist cosmos is one that ultimately forecloses entirely purposelessness, and thereby also undermines all forms of inclusiveness, non-duality, and the non-personal. The relation of purpose to purposelessness is more tricky than it appears. This essay attempts a direct reconfiguring of this relation through the concept of wu-wei as effortless and purposeless action.
Heideggers Ungebrauch
Authors: Kějūn Xià
Published: December 2021

This essay is concerned with a topic that has been widely discussed in East Asia for decades – the relationship between Martin Heidegger’s thought and Daoism. At the centre of my reflections is a motif that appears in Heidegger’s 1945 “Evening Conversation: In a Prisoner of War Camp in Russia, between a Younger and an Older Man” – a “doing that is a letting” (ein Tun, das ein Lassen ist). Starting from this, I discuss Heidegger’s approach to the Daoist “thinking of the useless” expressed in his Black Notebooks and other texts. In the development of Heidegger’s thought the “turning” (die Kehre) marks an important juncture. I propose speaking of a second or transcultural turning, which begins around 1943. For this transformation in Heidegger’s thought, what has been of outstanding importance is his preoccupation with Daoist texts, and especially his reading of the classical texts Lǎozǐ and Zhuāngzǐ. This is evident in his numerous explicit or implicit references to the Daoist classics. In 1945, in a situation of extraordinary emergency, Heidegger refers to Zhuāngzǐ’s motif of uselessness and the “necessity of the unnecessary”. This can be seen as a personal escape from responsibility, but also, importantly, as a way out of his deep entanglement with National Socialism. Although the way Heidegger proposes is arguably twisted and disturbing, its value lies in its providing a necessary perspective from which to unfold the critical potential of transcultural philosophy.