bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Video-Preprocessing on Deep Learning-based Surgical Skill Assessment
Authors: Wolf Georg , Geck Paulina Amelie , Hagenah Jannis , Maennel Georg , Keck Tobias , Rostalski Philipp , Ipsen Svenja
Published: September 2023

Automatic surgical skill assessment in robotic surgery based on video data is essential in facilitating faster learning curves for trainees while relieving expert surgeons from the time- and cost-intensive feedback process. Recent years have shown several advancements in this area by utilizing deep learning. While current research focuses on novel architectures, the influence of video-preprocessing on their performance remains unknown. In this work, we present the first investigation on the influence of video-preprocessing on deep learning-based surgical skill assessment. Thus, we integrated four preprocessing modules, i.e. Deblurring, Segmentbased Sampling, Optical Flow and the Combination of all of them, into skill assessment on the JIGSAWS dataset using a well-established network architecture. Despite all single preprocessing steps showing no clear improvement, the Combination of all steps showed higher median performance and lower variance. Furthermore, we performed frame-wise investigations on the influence of optical flow artifacts and their reduction in the combined setting. Our results highlight the potential of well-calibrated video-preprocessing for automatic surgical skill assessment.
Digital personalized medical insole process
Authors: Völz Diana , Schneider Julia , Wuttke Ulrich
Published: September 2023

Medical insoles are used to correct patient’s foot malpositions or to relieve certain foot areas from pressure. The required insole type depends largely on the presenting clinical picture and the individual’s needs. Accurate fit of medical insoles is critical to wearer acceptance, which is a necessary precondition where further serious injury is to be prevented. An end-to-end digital process offers the potential to better adapt insoles to the personalized patients’ foot geometry and pressure load. Furthermore, the whole gait-cycle could be included in the digitalization process and the adaption could consider special needs of different gait phases. This hasn’t been done, yet. For this purpose, a digital process chain was developed and prototypically tested in collaboration with an orthopaedist. 3D scans of the foot geometry in various loaded conditions were compiled and the corresponding gait analysis images were mapped. Both results were overlaid in a CAD program to create a model and identify the clinical picture. Adapted to the geometry of the foot, a volumetric model of the medical insole was built, individual stress zones were separated and filled with lattice structures of different parameters. The insole was 3D printed. The results of the present examination show benefits in using the loaded foot scan to model insoles, as malpositions can be checked automatically via standard (digital) tests. While it is possible to model and print medical insoles in one piece with differing strengths, there is limited information about the influence of the designed lattice structure on a specific printing result (i. e. the material behaviour).
SkillsLab+ - Digitization of the Otoscopy Station through State of the Art Methods of Augmented Reality
Authors: Gießer Christian , Karunairatnam Archsayan , Schmitt Johannes , Brück Rainer
Published: September 2023

The paper discusses SkillsLab+, a medical augmented reality application developed to digitize the practical course SkillsLab. This application provides medical students with a digital tool to learn and apply practical hand movements, initial treatment, and diagnostic techniques. The otoscopy station, one of the stations in SkillsLab+, allows students to learn the correct use of otoscope inserts and perform case discrimination. The digitization of this station provides several advantages over traditional teaching methods. The implementation of the application with the Unreal Engine on the Magic Leap One headset is discussed. The application is modular, allowing the addition of new stations with ease. Anatomically correct models and 3D models of diagnostic tools provide the necessary realism and precision for the application. Learning and exam modes have been included in the application to enhance the learning experience. The evaluation of the application was conducted using a questionnaire completed by 79 bachelor and master students from the fields of medical informatics and digital biomedicine and health sciences. On average, 54.25% of students had a positive response to the digital otoscopy station in the SkillsLab+ application, while 22.71% had a negative response. The questionnaire results indicated that the digitization of the otoscopy station through augmented reality in the SkillsLab+ application was well-received by the students. The SkillsLab+ application digitizes the practical course SkillsLab and offers several advantages over traditional teaching methods. It provides students with a digital tool to learn and apply practical hand movements, initial treatment, and diagnostic techniques. The otoscopy station in SkillsLab+ allows students to learn the correct use of otoscope inserts and perform case discrimination. The digitization of this station provides students with a digital tool that can be used anywhere, any number of times. The evaluation of the application using a questionnaire showed that the application was well received by the students.
Landmark-Based Generation of Common Ultrasound Views and 17-Segment Model from Cardiac Computed Tomography
Authors: Janorschke Christian , Xie Jingyang , Lu Xinyu , Grehn Melanie , Blanck Oliver , Schweikard Achim
Published: September 2023

Complex medical therapies can require a multitude of imaging modalities and are often supervised by a team with different medical backgrounds. This necessitates the conversion of medical data between technical systems and visualizations. In the case of stereotactic arrhythmia radioablation therapy (STAR-therapy) of the left ventricle, electroanatomical mapping, ultrasound (US) and computed tomography (CT) are the central imaging modalities that are needed for defining the target volume as well as for the examination and validation pre and post treatment. In the interest of developing a motion management system for STAR-therapy, a way to transfer information and visualizations between these modalities and to compare data from different patients is needed. For this purpose, we present a landmark-based approach for the generation of commonly used ultrasound views and the 17-segment model from cardiac computed tomography (CCT) data. The developed tool can already be used to aid the examination process by extracting function-based views from CT datasets, comparing them to live US imaging, localize CT structures within the 17-segment model or to transfer information like motion or strain data from one modality to the other. In the future, it will be used in the development of a live or predictive management system for cardiac and respiratory motion.
Microfluidic devices for light stimulation of cell suspensions: experimental analysis of the flow behaviour using a micro-PIV system
Authors: Thürling Mario , Verena Witt Anna , Mau Robert , Drobek Christoph , Seitz Hermann
Published: September 2023

Photobiomodulation, the light stimulation of regenerative active cells, offers great potential for promoting tissue repair and regeneration. In this study, we show the design and fabrication of two microchannel devices for light stimulation of cell suspensions. The microchannels in the 3D-printed devices allow the uniform distribution of cells and exposure to light. Our experimental results demonstrate the ability of these microfluidic devices to improve light intake of cells in suspensions during photobiomodulation, thus enhancing the therapeutic potential.
Developing a new focal vibration and heat therapy system
Authors: Abbasimoshaei Alireza , Laatz Dominik , Kern Thorsten Alexander
Published: September 2023

Vibrational heating therapy is a type of physical therapy that uses the application of heat and vibrations to stimulate the body’s healing process. The therapy is believed to promote circulation, reduce inflammation, and relieve muscle tension. It is often used to treat conditions such as arthritis, fibromyalgia, and sports injuries. This paper presents the design-decisions for a device treating muscle soreness and to increase muscle strength through a combination of heat and vibration therapy to the upper leg. The system comprises farinfrared heat elements for heat transfer and two types of eccentric rotating masses (ERMs) and a linear resonant actuator (LRA) to vibrate muscle tissue. It discusses heating and vibration capability and performance. To optimize the mechanical effects of vibration therapy, the device must excite the muscle with an acceleration of more than 2 g and with a bandwidth as wide as the range of the muscle natural frequencies. For testing the heating and vibrational systems, they were tested in the same device on six different subjects with ethics permission from Technical University of Hamburg to obtain accurate results. Both ERMs were driven by DC power and yielded a bandwidth of about 30 Hz with a linear progression of acceleration over frequency, while the LRA was driven by AC power and achieved a bandwidth of about 24 Hz in the form of a bell curve. Also the selected heating element provides the desired temperature between 40 ∘C to 50 ∘C. Overall, the initial technical study showed promising measurement results and a mechanical effect in using this combination of heat and vibration therapy. As an outlook, the technical design of the next version of the device will include multiple actuators around the leg to provide more acceleration and aims to combine multiple LRAs with slightly shifted natural frequencies into one actuator module to extend the bandwidth.
Design and Development of a Bioreactor System for Mechanical Stimulation of Musculoskeletal Tissue
Authors: Bartel Theresa , Mortimer Jeremy W. , Zylka Waldemar , Paxton Jennifer Z. , Vorstius Jan
Published: September 2023

We report on the development of a bioreactor system for mechanical stimulation of musculoskeletal tissues. The ultimate object is to improve the quality of medical treatment following injuries of the enthesis tissue. To this end, the tissue formation process through the effect of mechanical stimulation is investigated. A six-well system was designed, 3D printed and tested. An integrated actuator creates strain by applying a force. A contactless position sensor monitors the travels. An electronic circuit controls the bioreactor using a microcontroller. An IoT platform connects the microcontroller to a smartphone, enabling the user to alter variables, trigger actions and monitor the system. The system was stabilised by implementing two PID controllers and safety measures. The results show that the bioreactor design is suited to execute mechanical stimulation and to investigate the tissue formation and regeneration process. The bioreactor reported here can now be implemented in tissue engineering applications including tissue specimen.
Universal test bench for repeatable multiparametric cochlear implant insertion tests
Authors: Böttcher-Rebmann Georg , Lange Vera , Schell Viktor , Cramer Jakob , Lenarz Thomas , Rau Thomas S.
Published: September 2023

Introduction: In cochlear implant surgery, the insertion of the electrode array (EA) into the cochlea is critical as its implementation can influence the preservation of residual hearing. Insertion tests are the primary method for basic research on parameters influencing the insertion and help to further improve the design of EAs and surgical techniques. With automated insertion devices close to clinical application, a consensus on optimal insertion parameters is needed, which requires reliable testing methods. Moreover, the limited availability of EAs needs to be considered. We propose a test setup that provides high repeatability and flexibility for various research questions. Methods: Design requirements for multiple types of experiments such as variability of insertion speed or trajectory as well as cochlear geometry guided the computer aided design of the test bench. Moreover, repeated insertions with the same EA were supposed to be possible. To evaluate its functionality, insertion tests into a 3D printed cochlea model were performed and recorded. Results: The central components of the test bench are a linear actuator driving the EA and a goniometer changing the orientation of the target - a cochlea model or a specimen. A force sensor can be mounted below the target to measure forces in its frame of reference. The experimental results show high reproducibility of insertion forces for recurring trajectories with a single EA. Conclusion: The test bench enables reproducible insertion tests with a high number of repetitions and reduced EA usage. This allows a more detailed investigation of broadly discussed influences on the insertion such as the insertion speed or trajectory as well as cochlear geometry and can thereby drive future EA development.
Controlling Leakage of Potential Juxtacrine Self-Assembled Monolayer-BMP-2 Surfaces
Authors: Holtkamp Julia , Jennissen H. P.
Published: September 2023

A question which has been intriguing researchers since 1969 is whether covalently linked hormones or growth factors on surfaces are still biologically active i.e. still bind and activate cell surface receptors in the insoluble state. There is evidence of release or leakage of rhBMP-2 covalently linked to self-assembled monolayers (SAMs) on gold surfaces. After detergent wash (SDS), juxtacrine surfaces with rhBMP-2 appear functionally feasible at fM release.
Impact of the Right Atrium on Arrhythmia Vulnerability
Authors: Fitzen Nikola André , Martínez Díaz Patricia , Dössel Olaf , Loewe Axel
Published: September 2023

Atrial fibrillation (AF) is one of the most common cardiac diseases. However, a complete understanding of how to treat patients suffering from AF is still not achieved. As the isolation of the pulmonary veins in the left atrium (LA) is the standard treatment for AF, the role of the right atrium (RA) in AF is rarely considered. We investigated the impact of including the RA on arrhythmia vulnerability in silico. We generated a dataset of five mono-atrial (LA) and five bi-atrial models with three different electrophysiological (EP) setups each, regarding different states of AF-induced remodelling. For every model, a pacing protocol was run to induce reentries from a set of stimulation points. The average share of inducing points across all EP setups was 0.0, 0.8 and 6.7% for the mono-atrial scenario, 0.5, 27.3 and 37.9% for the biatrial scenario. The increase in inducibility of LA stimulation points from mono- to bi-atrial scenario was 0.91 ± 2.03%, 34.55 ± 14.9% and 44.2 ± 14.9 %, respectively. In this study, the RA had a marked impact on the results of the vulnerability assessment that needs to be further investigated.
Temperature-triggered liquefication of hydrogels for intentional implant removal
Authors: Finck Laura , Hagemann Valentin , Behrens Peter , Menzel Henning
Published: September 2023

The Diels-Alder (DA) reaction is one of the most studied thermoreversible reactions, suitable for the preparation of thermoreversible crosslinked materials. In this study, temperature- triggered liquefaction of DA hydrogels will be investigated. A DA model reaction is used to determine the retro- DA temperature of the two stereoisomers. A hydrogel based on furan-functionalized Poly-(N-(2-hydroxy-propyl) methacryl amide (PHPMA) and 4-arm-polyethylene glycol (PEG) with maleimide endgroups is rheologically investigated and liquefaction experiments are performed.
Prototype of a Coupling Device to Investigate Focused Ultrasound-Induced Inertial Cavitation for Drug Delivery Applications
Authors: George Benedikt , Wittenbrink Michel , Savšek Ula , Kroh Christian , Fischer Dagmar , Ermert Helmut , Rupitsch Stefan J.
Published: September 2023

Focused ultrasound (FUS) can be used as a drug delivery application for localized chemotherapy to treat cancer. The effect of ultrasound-induced inertial cavitation is promising to trigger drug release from nanocarriers. To investigate this effect, usually, a passive cavitation detection setup is employed. However, applying such a setup is challenging for in vivo experiments, as the test object may need to be fixed inside the water tank. Thus, we present a prototype of a coupling device that could significantly simplify experiments. Since this setup favors undesired sound wave interference and their resulting exceedance of the Mechanical Index, we additionally investigated different signal lengths. The occurrence of standing waves at a signal length of 44 cycles can both be derived from a changing cavitation activity and our calculations. The appearing interference also results in a mean increase of the cavitation activity by ≈ 5.1 %, verified by our experiments as well.
Implementation of an Ultrasonic-Based Link for Percutaneous Communications
Authors: Helmerich Jan , Schaechtle Thomas , Wich Manfred , Szabo Benedikt , Stieglitz Thomas , Rupitsch Stefan J.
Published: September 2023

The emerging desire for implantable devices assisting individuals’ medical treatments requires their connection to systems placed outside and inside the human body. Their exchange of crucial information on health parameters at different locations may allow them to optimize the patient’s therapy by evaluating the received and transmitted data. Electromagnetic communication methods are the current implementation of choice for such applications. Yet, this kind of communication is often limited to shorter distances due to their restrictions on safe electromagnetic levels, causing no damaging heat dissipation in human tissue. In contrast, employing ultrasound as an alternative method will allow for long-distance communication in the same medium by simultaneously guaranteeing safety requirements for the patient. In this contribution, we will demonstrate a proof-of-concept for which we modulate ultrasonic carrier signals with the help of a low-power consumption microcontroller TI-MSP430. For this, two identical non-focused ultrasonic transducers will be used to receive and send messages through a tissue-mimicking phantom placed in a water tank, indicating the potential of ultrasonic signals as the carrier of information.
Extension of an Existing VR Memory Training with Haptic Impressions due to a Haptic Vest
Authors: Schmücker Vanessa , Jakob Rebekka , Grensing Florian , Brück Rainer , Eiler Tanja
Published: September 2023

Cognitive performance is an important aspect of life. Not only does thinking enable us to act, there is also an interaction between cognitive performance and mental health. It is therefore increasingly important to train and practice one’s cognitive abilities and benefit from brain plasticity. According to Vester’s model of learning types visual, auditiv and haptic impression are imporant for learning. An existing memory training application, which transfers the concept of the game Pairs with personal memories into virtual reality (VR), has now been supplemented with a haptic impression. The original application already establishes the visual and auditory perception channels. With new haptic hardware constantly appearing on the market, the Tactsuit X40 haptic vest from bhaptics has now made it possible to include a third perceptual channel with a wide variation of haptic sensations on various parts of the upper body. Each playing card is associated with an individual image, a piece of music and a vibration pattern. All of which are designed to help the user remember the position of the card. Each of these aspects can be freely enabled and disabled. The result of this work is an application which aims to find if and how strongly haptic impressions influence memory performance. By taking more types of learning into account, we hope to achieve a better memory training. A study has been designed to evaluate the specific aspects of the application and is currently being carried out. In addition to the self-generated haptic patterns, it is also possible to generate haptic impulses based on audio sources. These could possibly provide further support in this application.
Lymphoma Cell Nuclei Classification using Color and Morphology Features
Authors: Naji Hussein , Hahn Lunas , Bozek Katarzyna
Published: September 2023

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of Non-Hodgkin’s Lymphoma, presenting a great challenge for treatment due to its highly heterogeneous nature. DLBCL is diagnosed based on microscopy images of patient tissue samples. To help gain a better understanding of DLBCL, we developed an automated computer vision method to analyze morphological and color-based information within patient biopsies. We analyzed a dataset of whole slide images of DLBCL by segmenting individual cells and representing cell morphologies through a set of engineered features. The features were evaluated using a variety of visualization and machine learning (ML) classification techniques. Current state-of-the-art deep learning methods use images as the input in classification tasks achieving high performance but lacking in interpretability. A big challenge lies in finding out what features the pixel-based deep learning methods utilize in prediction. Here, we present a technique that not only yields high prediction accuracy but also provides insights into which of the features are key for prediction. We show that the color-based features have the highest importance for cell classification, allowing for the accurate identification of various cell types with an accuracy of 84% in a multi-class and 91% in a binary classification. Our results provide valuable insights for exploring cell image datasets to gain an in-depth view of the tumor microenvironment.
Detection of activities of daily living with decision trees through a technical assistance system
Authors: Krabbe Aileen , Seidel Roman , Hirtz Gangolf
Published: September 2023

To cope with the increasing demands in care due to the aging society and the simultaneous lack of professional caregivers， a technical assistance system can help to monitor elderly people in their own homes and to support professional caregivers and caring relatives. The technical assistance system consists of a smart sensor with an omnidirectional camera on the ceiling of each room and additionally, other smart home sensors in an apartment for elderly persons. Based on smart sensor data, the positions, poses, and activities of the patient are detected with the help of machine learning (ML) techniques. In this work a temporal behaviour model of the patient is developed to recognize activities of daily living (ADL) such as "eating", "sleeping" or "emergency". For this, the actions (e.g., walking, sitting) and the location in the current room of the patient, as well as the data of other sensors in the apartment are used. This input data is fed into a trained decision tree of depth 14, which ultimately determines the patient’s activity. The accuracy for detecting activities of daily living with the decision tree is 96.47%, where the activities can be detected in real-time.
App for the prevention of malnutrition in vegan diet
Authors: Seifert Oskar , Benselama Selima , Sohrabi Keywan , Gross Volker , Scholtes Michael
Published: September 2023

More and more people are changing their lifestyle to a vegan diet. On the one hand, a vegan diet can help reduce the risk of nutrition-related diseases, but on the other hand, the vegan diet itself poses the risk of malnutrition. Therefore, nutrient intake should be managed and any nutrient interactions should be considered. The aim of this paper is to work out a development strategy for a nutrition app for a vegan diet. With the help of a market analysis, unique selling proposition were identified and regulatory requirements have been determined. It could be shown that there is currently no adequate app that is approved as a medical device, focuses on the vegan diet and considers nutrient interactions. The necessary regulatory requirements could be identified. There are many apps available, but without medical device approval. From the authors' perspective, this would be necessary to ensure a high level of safety and health protection for users.
Development and Evaluation of a Cost-effective IMU System for Gait Analysis: Comparison with Vicon and VideoPose3D Algorithms
Authors: Wilhelm Nikolas , Micheler Carina M. , Lang Jan J. , Hinterwimmer Florian , Schaack Victor , Smits Ricardo , Haddadin Sami , Burgkart Rainer
Published: September 2023

This study aimed to develop and evaluate a costeffective Inertial Measurement Unit (IMU) system for gait analysis, comparing its performance with the Vicon system and the VideoPose3D algorithm. The system comprises five calibrated sensors and a mobile app to measure lower body orientation during gait and stair climbing. Eight healthy participants were involved in the experiment, each performing ten repetitions to analyze hip and knee flexion angles. The IMU system demonstrated significantly lower mean square error than deep learning-based approaches and comparable results to the Vicon system, indicating its potential for clinical and research applications.
An approach to privacy-aware image analysis on edge devices using CNNs
Authors: Bendig Fabian , Naroska Edwin , Weberskirch Marcus
Published: September 2023

This paper presents our approach to a privacy preserving person detection algorithm on edge computing devices. It utilizes a commonly used neural network architecture (VGG16) to encode an image by passing it through a fixed number of layers of the network on the edge device. The resulting feature vector can then be transmitted over the network to a more powerful computer (e.g. in the cloud) to be passed through the remaining layers of VGG16. As a result, the transmitted feature vector is only an abstract representation of the image. However, our research has shown that it is in fact possible to reconstruct most images by their respecting feature vectors if a potential attacker can tap into the network transmission by using a decoder network. Our approach to mitigate that risk is to preprocess the transmitted feature vector randomly by different manipulation methods. We used methods like mean filter or random null value insertion to manipulate the feature vector before it gets transmitted and show that those methods are able to counter the reconstruction capabilities of a decoder network while still preserving the capabilities of the original VGG16 network. The actual VGG16 network was used for object detection.We used the faces in the wild dataset and utilized two different approaches to confirm our approach. First, we used the VGGFace-Network on the decoded images and tried to let it identify people from the former mentioned dataset. The second approach used a group of 26 participants who had to match the decoder image to one of five images. In our experiments, we found different combinations of manipulation and number of layers on the edge device to preserve the detection capability of VGG16 (e.g. object detection) while preventing VGGFace and the participating group from identifying the shown people.
An affordable and safe system for game-based therapy of the ankle joint
Authors: Shah Nazar Peiman , Luebbe Nico , Pott Peter P.
Published: September 2023

Musculoskeletal and nervous system injuries and strokes can influence the ankle in a way, that rehabilitation exercise is inevitable to regain a patient’s quality of life. However, increasing needs for physiotherapists and complex machinery for independent rehabilitation limit the patient’s possibility of experiencing proper care. One approach to address this issue is developing an affordable, safe, and cheap treatment solution. This paper presents a mechanically actuated ankle rehabilitation mechanism, which incorporates the use of the patients’ upper limbs to work on the ankle's range of motion. The mechanism consists of a Four-Bar linkage (FBL) to translate rotary motion into an oscillating angular displacement of the ankle. It provides the base for gamified ankle rehabilitation, acting as an input device for the game, controlled by the user; adopting the mechanism with the commercial games and required steps for designing a game for rehabilitation purposes.
The potential role of 3D-printed phantoms in quality control of artificial intelligence-based algorithms in medical imaging
Authors: Pashazadeh Ali , Hoeschen Christoph
Published: September 2023

To ensure accurate and consistent imaging of patients, medical imaging systems are controlled and tested using phantoms. Despite the availability of commercial standard phantoms for decades, 3D printing technology has gained special attention as a tool for producing accurate and costeffective tissue-mimicking phantoms. As artificial intelligence (AI) becomes increasingly prevalent in medical imaging, dedicated phantoms are needed for testing their reliability, robustness, and quality before they are implemented in clinical settings. In this context, 3D-printed imaging phantoms, which have specific requirements relevant to AI models, can play a crucial role. Due to its unique ability to create phantoms of almost any complexity, 3D printing technology seems a suitable approach for the quality control of AI models in medical imaging. The following reviews some of the works that used 3D-printed technology to create custom-built phantoms for use in Computed Tomography (CT), nuclear imaging, Magnetic Resonance Imaging (MRI), and ultrasound imaging. The focus of this short review is on the accuracy of 3D-printed technology in creating imaging phantoms. In the end, the potential of the 3D-printed phantoms in testing and quality control of AI-based algorithms in radiology is discussed.
Simulation study of the effect of the geometrical parameters on the performance of a beta probe
Authors: Pashazadeh Ali , Hoeschen Christoph
Published: September 2023

An intraoperative probe is a small tool used to identify, locate, and dissect pathological lesions during surgery and confirm their removal. The most common type of probe is the gamma probe, which detects gamma-emitting sources. Despite the successful use of gamma probes in clinics, their application can be limited when the background radiation from healthy tissue nearby or the injection site is high. In these cases, the use of beta probes that detect beta-emitting radiotracers would be beneficial. The shorter range of beta radiation compared to gamma radiation would result in improved detection efficacy when background radiation is significant. In this simulation study, we examined how geometrical parameters may impact the performance of a beta probe. Our results showed that the source depth inside the phantom and detector size affected the performance of the beta probe. We also proposed and evaluated two designs of beta probes capable of adjusting their performance.
Silent ICU based on IEEE 11073 SDC
Authors: Kasparick Martin , Klotz Tobias , Thürk Gregor , Andersen Björn , Rother Benjamin , Golatowski Frank , Neumuth Thomas , Rockstroh Max
Published: September 2023

Patients and caregivers suffer from alarm-related noise in today’s hospitals. While this is a topic for all fields of care, this challenge is especially relevant for intensive care units (ICUs). The noise harms patients, hinders the recovery process, or can even lead to psychosis. For the caregivers, noise causes an enormous stress level and in combination with the high number of clinically irrelevant or false alarms it leads to alarm fatigue and desensitization. These problems result in documented deaths of patients. Therefore, we present a demonstrator of a Silent ICU. Based on a distributed alarm system, the medical devices at the bedside do not create any audio alarm signals, as long as a remote alarm notification system is connected and works properly. An ICU bed place consists of devices from different manufacturers. Thus, a standardized interconnection is necessary. Therefore, we use IEEE 11073 Service-oriented Device Connectivity (SDC) to create a cross-manufacturer distributed alarm system with components from three different companies. A fourth company provides a documentation system for this demonstrator. Patients and caregivers will greatly benefit from Silent ICUs and smart distributed alarm systems that will be build based on interoperable cross-manufacturer environments.
Basic studies on the influence of hemorrhage on the antimicrobial effect of visible light in a trachea model
Authors: Nuding Katharina , Buehler Jule , Sicks Ben , Hoenes Katharina , Lotfi Ramin , Radermacher Peter , Spellerberg Barbara , Hessling Martin
Published: September 2023

Ventilator-associated pneumoniae (VAP) are a major problem in intensive care units. Previous in vitro experiments revealed that blue or violet luminescent endotracheal tubes are capable of inhibiting bacterial growth and may thus prevent pathogens from entering the lung. However, while these in vitro studies were conducted in a relatively transparent bacterial suspension, subglottic secretions around endotracheal tubes can also contain highly absorbent components, such as blood. To investigate if light has an antimicrobial effect under such conditions, staphylococcal solutions containing various absorbent components were irradiated by blue or violet luminescent endotracheal tubes for up to 24 h in a tracheal model. Light was generated externally by LEDs or lasers and entered the tube via light guides. An antimicrobial effect was observed for blue and violet light, which was, however, inhibited to some extent in the presence of light adsorbing molecules. Under these conditions, violet light had a stronger effect than blue at low absorptions, while at strong absorptions the effects converged, with blue light even exhibiting a slightly stronger impact. Significant differences between lasers and LEDs could not be detected. In our model, inhibition of bacterial growth could be observed even in the presence of light absorbing molecules. Illuminating endotracheal tubes with blue or violet light may thus represent a promising strategy to migration of bacteria from the oropharynx into the trachea and, thereby, possibly decrease the incidence of VAP.
Thermal measurements of a muscle-mimicking phantom during ultra-high field magnetic resonance imaging
Authors: Garcia Maíra M. , Oliveira Tiago R. , Chaim Khallil T. , Otaduy Maria C. G. , Bruns Christian , Svejda Jan T. , Bernarding Johannes , Erni Daniel , Zylka Waldemar
Published: September 2023

At ultra-high field MRI (Bo>7T) it is crucial to predict and control the patient safety. Commonly patient safety is controlled by the power deposited in the tissue (specific absorption rate - SAR). However, temperature distributions do not always correlate directly with SAR distributions, which makes temperature control also a crucial parameter to guarantee patient safety. In this work, temperature changes were accessed by MR thermometry, specifically by the proton resonance frequency shift technique (PRF). A phantom mimicking muscle tissue was used to evaluate the temperature rise caused by the radiofrequency (RF) absorption during 7T MRI, applied through a commercial birdcage head coil. A pulse-sequence protocol was implemented for both, the generation of temperature increase and the MR thermometry. To control the temperature, a digital thermometer was used, and oil tubes were utilized to dismiss the drift effects for PRF. Measurements of the phantom’s dielectric characteristics, i.e. conductivity and permittivity, were in good agreement with the literature values for muscle. Spatio-temporal evaluations showed a temperature increase in time via RF exposure and the feasibility of measuring temperature maps using the PRF shift method. The accuracy of the PRF shift method increased when the drift effects were quantified and dismissed, indicating a PRF reading accuracy differing less than 0.5 °C from the thermometer. Results also validate our heating and temperature imaging protocol. This study is a valuable contribution to the evaluation of heating effects caused by RF absorption and demonstrates potential impact on future thermal investigations, which may use different heating sources, as well validate thermal simulations.
Inkjet printability of Celecoxib drug solutions
Authors: Sannan Ahmed , Mau Robert , Eickner Thomas , Teske Michael , Grabow Niels , Seitz Hermann
Published: September 2023

Inkjet printing is a versatile tool for the precise positioning of droplets that is used in many application areas such as 3D printing, biotechnology or pharmacy. This work focused on comparing the inkjet printability of different drug solutions of celecoxib (CLX), a non-steroidal anti-inflammatory drug, to produce drug depots in medical implants. CLX was dissolved in dimethyl sulfoxide (DMSO), poly(ethylene glycol) diacrylate (PEGDA) and a mixture of DMSO and PEGDA in a ratio of 1:1. The pure solvents and the drug solutions were inkjet printed using a Nanoplotter 2.1 with the NanoTip J printhead (GeSiM mbH, Radeberg, Germany). The voltage was varied from 60 V to 150 V using a step size of 5 V. Droplet volume and the trajectory of the droplets were investigated. For DMSO, DMSO-CLX, DMSO-PEGDA and DMSOPEGDA- CLX, reproducible droplet formation occurred with a droplet volume of approximately 300 pl - 500 pl and not more than one satellite droplet in a voltage range between 60 V to 80 V. Inkjet printing of PEGDA and PEGDA-CLX was not reproducible in the range of 60 V to 150 V. DMSO, DMSOPEGDA, DMSO-CLX and DMSO-PEGDA-CLX showed a high inkjet printability. In contrast, inkjet printability of PEGDA and PEGDA-CLX was very limited.
Enabling Data-Driven Nursing Innovations: User-centered Development of a Nursing Data Module
Authors: Warnecke Maren , Holle Daniela , Burmann Anja
Published: September 2023

The documentation landscape for nursing care data in Germany is predominantly heterogeneous and unstructured. Therefore, insightful methods such as Artificial Intelligence (AI) are difficult to implement. We propose a stepwiseapproach that identifies relevant information from nursing theory and practice and maps it to a standardized nursing core data set to enable data-based improvement of nursing care. This can be used for various use-cases in care, such as risk detection and prevention in diverse care contexts. Many care processes can benefit of a cross-facility and standardized repository and associated applications. We propose an approach that enables the use of AI while leveraging consensus and evidenced-based expert knowledge from nursing science.
Fully integrated Windows framework for source localization with MNE Python and FreeSurfer
Authors: Oppermann Hannes , Wulf Simon , Komosar Milana , Haueisen Jens
Published: September 2023

There is a variety of software packages, toolboxes, or libraries for the analysis and processing of neurophysiological data such as EEG and MEG. Many of these solutions provide algorithms for both, sensor-space analysis and sourcespace analysis. Especially with the solutions that run on Windows machines, it is noticeable that the step of the volume model generation is usually not included, since the state-ofthe- art software for this (FreeSurfer) is a Unix-based software and thus not available forWindows machines. Therefore, our goal was to develop a fully-integrated software solution for Windows machines, accessing all processing steps already implemented in an existing toolbox and using FreeSurfer in the same system. Due to its widespread use, we chose MNE Python as the basis for our fully integrated software solution. We used the Windows Subsystem for Linux to create a virtual Linux kernel for the FreeSurfer installation. To demonstrate the workflow, the libeep, and AutoReject libraries have been added. A 64-channel EEG recording during right-hand movement (ME) and imagination (MI) was used to test the implemented workflow. The developed framework consists of several modules within Python, mainly using existing scripts and functions. The library libeep was integrated to read the EEG data with the ‘.cnt’, eeprope format. AutoReject was used to automatically interpolate detected bad channels or to reject complete epochs. FreeSurfer was successfully integrated and customized Python scripts enabled the communication between MNE Python on a Windows machine and FreeSurfer on a virtual Linux kernel. With the above-mentioned EEG dataset, we performed source reconstruction and were able to show ERD/S patterns for both, ME and MI. Our new, fullyintegrated software framework can be used on Windows machines to perform a complete process of source reconstruction.
Fabrication of polymer-based stents: Impact of test specimen manufacturing protocol
Authors: Koper Daniela , Kaule Sebastian , Grabow Niels , Schmitz Klaus-Peter , Oschatz Stefan
Published: September 2023

Various manufacturing techniques are available for polymer stent fabrication. Polymer semi-finished products can be prepared using solvent based methods, e.g. dip coating, as well as thermal processes, e.g. extrusion. These different methods may lead to an altered polymer crystal structure, resulting in a different deformation mechanism during mechanical stress. For the material property characterization needed for implant development, the test specimens usually are prepared using laser-cut or die-cut methods. Due to these different preparation protocols, a change in polymer microstructure, causing a material property variation, may also result. For this purpose, comparison of laser-cut versus die-cut of PLLA films has been performed. PLLA films have been prepared by dip-coating and were evaluated with respect to structural, thermal, and mechanical properties. In this study, a combination of uniaxial tensile tests, SEM and DSC studies was used. The results of the mechanical tests showed drastic differences in the elongations at break of die-cut specimens compared to laser-cut ones. The results point out formation of complex crystal structures during the manufacturing process. By the use of SEM imaging and DSC measurements, we were able to attribute these changes to the different plastic deformation mechanisms.
Pirfenidone release from ophthalmic implants – perspectives for a drug-eluting microstent for glaucoma therapy
Authors: Reske Thomas , Stahnke Thomas , Bajer Dalibor , Grabow Niels , Khaimov Valeria , Guthoff Rudolf F. , Schmitz Klaus-Peter , Siewert Stefan
Published: September 2023

Elevated intraocular pressure is the main risk factor for glaucoma and its adjustment to physiological levels can prevent progression of the disease. If conventional drop-based glaucoma therapy fails, surgical interventions such as trabeculectomy or the application of implants, which drain aqueous humour from the eye and thus reduce intraocular pressure, are used as final therapeutic procedures. These interventions are becoming increasingly minimally invasive and the drainage implants are getting steadily smaller, which is why these interventions are now called microinvasive glaucoma surgery (MIGS). Both, surgery and drainage implant-based glaucoma therapy are limited by wound healing processes and fibrosis that occlude the newly created drainage pathways for the aqueous humour. To suppress unwanted postoperative fibrosis coupled with an increased extracellular matrix production, cytostatics like mitomycin c or 5- fluorouracil are currently used, which are associated with side effects. Therefore, more specific antifibrotic agents are key for a durable functionality of the interventions in glaucoma therapy. In this study a specific active substance (pirfenidone, PFD) was added in a polymer matrix for controlled release. Previous studies have shown that the release of pirfenidone from a thermoplastic silicone polycarbonate elastomer, which could be used as a material for a glaucoma drainage implant, has been relatively fast. To decelerate the release the influence of the alternate polymers Poly-L-Lactide (PLLA) and Poly-D,LLactide (PDLLA) as alternative drug carriers was investigated. Furthermore, a reduction of the pirfenidone content was used to delay the release.
Test methods for evaluation of balloon expandable vascular stents – measurement of radial strength and stiffness
Authors: Brandt-Wunderlich Christoph , Schmidt Wolfram , Thiesen Alexander , Reinhardt Falk , Stiehm Michael , Schmitz Klaus-Peter , Siewert Stefan
Published: September 2023

The radial strength of balloon expandable stents represents a key property for a successful recanalization of sclerotic blood vessels. This study focuses on the most commonly used method for investigation of radial strength and radial stiffness via segmented head test setup. A custom made user software was used for evaluation of the radial force curves considering requirements of international standards such as ASTM F3067. Contributing factors during measurement such as friction and test setup deformation as well as the single cycle and multi cycle approach were addressed and discussed.
Determination of material properties from tissue samples of low strength and size
Authors: Lebahn Kerstin , Tautorat Carsten , Bonin Franziska , Schmidt Wolfram , Grabow Niels
Published: September 2023

Uniaxial tensile tests are the most common method for investigating the mechanical properties of materials. However, due to the small strength and size of certain materials, larger conventional universal testing machines are sometimes not suitable for performing elongation testing, so dedicated test setups are required. Therefore, the authors developed a testing device to measure the mechanical properties of small, flexible materials, e.g. fragile specimens of the capsular bag of the eye. Also different variants for specimen holders were designed and tested. Initial tests using eggshell membranes as a model material demonstrated the functionality of the test setup at different strain rates.
Ceftriaxone-loaded PLLA-co-PEG nonwovens towards implant-associated infection prevention
Authors: Oschatz Stefan , Koper Daniela , Illner Sabine , Senz Volkmar , Schmitz Klaus-Peter , Grabow Niels
Published: September 2023

Implant-associated infections remain a challenge in biomedical engineering and prevention of such complications is a topical subject. For that, local drug delivery is associated with a number of advantages over systemic antibiosis. In this context, incorporation of antibiotic drugs into fibrous nonwovens is a promising approach for the generation of antiinfective implant envelopes or wrappings. Such materials can be manufactured in large scale and electrospinning process is suitable for a wide range of drugs to be incorporated. With regard to increasing numbers of pacemaker implantations and associated risk factors for infections, biodegradable ceftriaxone loaded poly(L-lactide)-co-poly(ethylene glycol) (PLLA-co-PEG) nonwovens have been characterised concerning the influence of the drug on morphology, thermal and mechanical properties and drug release behaviour. Our results show that the chosen material combination is promising for further approaches towards an antiinfective nonwoven pacemaker envelope.