bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract

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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.