bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dexamethasone release from photopolymerised PEGDA700 for cochlea drug delivery
Authors: Thomas Eickner , Teske Michael , Rekowska Natalia , Senz Volkmar , Schmitz Klaus-Peter , Grabow Niels 
Published: February 2021

Abstract
Sustained local drug release and high local drug concentrations can be achieved by specially designed DDSs, which can be created for different applications. This results in therapeutic drug amounts at the site of action, simultaneously providing a very low drug amount in total. Bodily compartments that contain liquids may be used to transport the drugs from DDS into the tissue, such as the cochlea with the perilymph in the case of cochlea implants. However, predominantly dry environments, such as the middle ear, are lacking such a medium but may deliver enough moisture for the use of swellable DDS through the surrounding mucus membranes. Therefore, DDS with new functionalities are needed to ensure a sustained drug release. In this study, the release of dexamethasone out of a photopolymer system is presented. The system is built from UV-polymerized PEGDA followed by the incorporation of dexamethasone via swelling. The drug release is tested in vitro with isotonic NaCl solution for specified time periods, showing two phases: a swelling phase and a release phase. After the swelling phase the concentration of dexamethasone in the release medium was not controlled by diffusion, although sink conditions were ensured. In contrast, this system can be used to release the drug until equilibrium with a final medium concentration that is far below the solubility of dexamethasone. Hence, such DDS may be useful for dexamethasone delivery into the cochlea through the round window membrane by ensuring a constant concentration in the perilymph.
Optimization Framework to Identify Constitutive Law Parameters of the Human Heart
Authors: Kovacheva Ekaterina , Baron Lukas , Schuler Steffen , Gerach Tobias , Dössel Olaf , Loewe Axel 
Published: February 2021

Abstract
Over the last decades, computational models have been applied in in-silico simulations of the heart biomechanics. These models depend on input parameters. In particular, four parameters are needed for the constitutive law of Guccione et al., a model describing the stress-strain relation of the heart tissue. In the literature, we could find a wide range of values for these parameters. In this work, we propose an optimization framework which identifies the parameters of a constitutive law. This framework is based on experimental measurements conducted by Klotz et al.. They provide an end-diastolic pressure-volume relationship. We applied the proposed framework on one heart model and identified the following elastic parameters to optimally match the Klotz curve: C=313 Pa, bf=17.8, bt=7.1and bft=12A. In general, this approach allows to identify optimized parameters for a constitutive law, for a patient-specific heart geometry. The use of optimized parameters will lead to physiological simulation results of the heart biomechanics and is therefore an important step towards applying computational models in clinical practice.
Approaches for Solution-Processed Encapsulation of Printed Medical Wearable Devices
Authors: Chen Zehua , Gengenbach Ulrich , Koker Liane , Mansour Maher 
Published: February 2021

Abstract
Wearable medical devices offer a great opportunity to monitor human vital signs to improve healthcare. The use of printing technologies is a promising approach to fabricate the wearables. An encapsulation must be applied to achieve longterm stability and reliability of the printed wearables. In this paper, we discuss the encapsulation requirements of printed wearable medical devices. Different encapsulation approaches are illustrated by means of various examples. Thereby, the focus lies upon solution-processed encapsulation, including the compatible materials and printing technologies.
Modelling and prototyping of a microfluidic cartridge for extracting immune cells from small volume blood samples
Authors: Behrens Stephan , Sonntag Frank , Schmieder Florian 
Published: February 2021

Abstract
Within the human blood immune cells assume specific functions to modulate and control the human immune response. Consequently, they are used for the diagnosis and treatment of autoimmune and hematologic diseases. Traceless Affinity Cell Selection Technology (Fab-TACS® technology) is a new method for selective isolation of specific immune cells from blood samples. Currently, the technology is used in a 60 mL syringe-like cartridge, which is operated by a control unit (Fabian®). Nevertheless, diagnostic applications require the reduction of the sample volume to several microliters. Therefore, we developed a cartridge for the purification of small blood volumes with the aid of suitable scaling and simulation methods. By implementing a multi domain physical systems model of the established cartridge we could simulate the separation process. Based on that a microfluidic cartridge was designed and several prototypes were manufactured. To operate the microfluidic cartridge a setup and software for fluidic control were created. Afterwards the prototype cartridge and the microfluidic control were used to isolate lymphocytes from a buffy coat. By flow cytometric analysis we could show that it is possible to isolate lymphocytes with a purity that is comparable to the established 60 mL syringe-like cartridge.
Novel dry electrode EEG headbands for home use: Comparing performance and comfort
Authors: Haueisen Jens , Fiedler Patrique , Bernhardt Anna , Gonçalves Ricardo , Fonseca Carlos 
Published: February 2021

Abstract
Monitoring brain activity at home using electroencephalography (EEG) is an increasing trend for both medical and non-medical applications. Gel-based electrodes are not suitable due to the gel application requiring extensive preparation and cleaning support for the patient or user. Dry electrodes can be applied without prior preparation by the patient or user. We investigate and compare two dry electrode headbands for EEG acquisition: a novel hybrid dual-textile headband comprising multipin and multiwave electrodes and a neoprene-based headband comprising hydrogel and spidershaped electrodes. We compare the headbands and electrodes in terms of electrode-skin impedance, comfort, electrode offset potential and EEG signal quality. We did not observe considerable differences in the power spectral density of EEG recordings. However, the hydrogel electrodes showed considerably increased impedances and offset potentials, limiting their compatibility with many EEG amplifiers. The hydrogel and spider-shaped electrodes required increased adduction, resulting in a lower wearing comfort throughout the application time compared to the novel headband comprising multipin and multiwave electrodes.
In situ impedance measurements on postmortem porcine brain
Authors: Poßner Lucas , Laukner Matthias , Wilhelmy Florian , Lindner Dirk , Pliquett Uwe , Petkovic Bojana , Ziolkowski Marek , Knösche Thomas R. , Weise Konstantin 
Published: February 2021

Abstract
The paper presents an experimental study where the distinctness of grey and white matter of an in situ postmortem porcine brain by impedance measurements is investigated. Experimental conditions that would allow to conduct the same experiment on in vivo human brain tissue are replicated.
Water uptake of various electrospun nonwovens
Authors: Wulf Katharina , Senz Volkmar , Eickner Thomas , Illner Sabine 
Published: February 2021

Abstract
In recent years, nanofiber based materials have emerged as especially interesting for several biomedical applications, regarding their high surface to volume ratio. Due to the superficial nano- and microstructuring and the different wettability compared to nonstructured surfaces, the water absorption is an important parameter with respect to the degradation stability, thermomechanic properties and drug release properties, depending on the type of polymer [1]. In this investigation, the water absorption of different non- and plasma modified biostable nanofiber nonwovens based on polyurethane, polyester and polyamide were analysed and compared. Also, the water absorption by specified water wetting, the contact angle and morphology changes were examined. The results show that the water uptake is highly dependent on the surface modification and the polymer composition itself and can therefore be partially changed.
Development of a limbal fixation mechanism for a minimally invasive implantable glaucoma microstent
Authors: Siewert Stefan , Großmann Swen , Brandt-Wunderlich Christoph , Dierke Ariane , Stiehm Michael , Schmitz Klaus-Peter , Sahmel Olga , Kischkel Sabine , Schmidt Wolfram , Grabow Niels , Stahnke Thomas , Guthoff Rudolf 
Published: February 2021

Abstract
Glaucoma represents a chronic eye disease that becomes increasingly prevalent worldwide. Therapies are commonly based on the reduction of intraocular pressure (IOP). Implant devices for micro-invasive glaucoma surgery (MIGS) represent a promising therapy option in refractory cases but suffer from limitations in long term efficacy or from dislocation associated complications. Our approach of an innovative drug-eluting glaucoma microstent for MIGS was presented previously. Within the current work we developed concepts and prototypes of a mechanism for the fixation of our glaucoma microstent in the region of the corneal limbus. A tripod and a haptics design of the fixation mechanism were developed and manufactured. Semifinished products were tested with regard to dimensional stability and mechanical properties according to the standard ANSI Z80.27-2014. Considering the mechanical properties of ocular target tissues, a gelatin based in vitro model for the measurement of microstent retention force was developed. Retention force testing of microstent prototypes in vitro resulted in a proof of concept for the fixation mechanism. Future studies will focus on the use of smaller fixation fibers, for example commercially available suture material, and on an overall miniaturization of the fixation mechanism enabling the use of our applicator device with a 22G x 1½” cannula.
First results of computer-enhanced optical diagnosis of bladder cancer
Authors: Wittenberg T. , Hackner R. , Bocklitz T. , Krafft C. , Becker W. , Braun L. , Pohlmann P. , Miernik A. , Suarez-Ibarrola R. , Lemke M. N. 
Published: February 2021

Abstract
Bladder cancer is the sixth leading cancer cause worldwide. Non-muscle invasive tumors can be diagnosed and treated endoscopically. Based on biopsies alone, pathologists cannot determine the spatial organization of specimens, their relationship with each other, or their complete removal. To extend white light cystoscopy as the gold standard for bladder cancer detection, diagnosis and removal of small or flat lesions, new image-based technologies have been investigated. These include a stereo-cystoscope for improved orientation and navigation, computation of 2D and 3D panoramic images for extended visualization and documentation, as well as label-free fiber-based fluorescence-lifetime imaging (FLIM) and Raman-spectroscopy in combination with statistical data analysis. Combining all these technologies, cystoscopy can will be further enhanced to include new diagnostic possibilities.
A multispectral 3D-Endoscope for Cholesteatoma Removal
Authors: Wisotzky Eric L. , Rosenthal Jean-Claude , Hilsmann Anna , Eisert Peter , Uecker Florian C. 
Published: February 2021

Abstract
We present a stereo-multispectral endoscopic prototype using a filter-wheel to guide the removal of cholesteatoma tissue in the middle ear. An image-based method is used that combines multispectral tissue classification for the detection of tissue to be removed and 3Dreconstruction to determine its metric dimensions. The multispectral illumination used for tissue classification ranges from λ = 400 nm to λ = 500 nm with step-size of 20 nm, which results in six different narrow-band illumination modes. For classical RGB imaging and metric calculations, a broadband illumination mode is applied before and after the narrow-band illumination. The spectral information is augmented into the broadband mode using an overlay technique. The combination of multispectral imaging with stereoscopic 3D-reconstruction results in new valuable visualization of intraoperative data. This allows to generate a 3D-model of the patients anatomy highlighting the identified malicious tissue and compare the anatomical dimensions with pre-operative CT data.
Proof of Concept for Ozone-Based Disinfection of Heater Cooler Units
Authors: Markus Bongert , Jan Wüst , Justus Strauch , Dirk Buchwald 
Published: February 2021

Abstract
Heater Cooler Units (HCUs) are frequently used not only during heart surgery but also in ECMO therapy to regulate the blood temperature of patients. It is known from cardiac surgery that the water circuits of HCUs can be bacterially contaminated and under adverse conditions can lead to a nosocomial infection of the patient. The addition of chemical disinfectants to the water of HCUs is problematic. In addition, it is an increasingly significant cost factor due to the required material and personnel input. The aim of this research project is both the development of an automated device for disinfecting water in HCUs and proof of its effectiveness. The device is based on ozone, a substance with known antimicrobial properties. To prevent ozone from coming into contact with the HCU components, the water is irradiated with UV light (254nm). Two bypasses and ozone sensors guarantee a complete elimination of residual ozone. The effectiveness of the device was tested by series of experiments with the surrogate germ, Pseudomonas aeruginosa. The device allows a wide range of ozone concentrations and exposure times to be selected. In previous test series, it has been shown both that a reduction of the bacterial count to drinking water quality can be achieved with a treatment time of only one hour, and that self-cleaning can be carried out effectively before clinical use, and in standby mode. Attention must be paid to the water quality in HCUs as a potential source of infection, regardless of where they are used. The "proof of concept" showed an excellent disinfection effect with simultaneous elimination of excess ozone to drinking water levels. The number of indicator bacteria in the water tank of the dummy HCU was reduced by approx. 98% after only 30 minutes.
Real World Experience with an Optimized Control Scheme for a Ventricular Assist Device
Authors: Steingräber Robert , Kiesner Matthias 
Published: February 2021

Abstract
A closed-loop control software for the new mobile Berlin Heart EXCORR driving unit was optimized to balance usability, durability, pump wash out, blood stress and power consumption. The piston of the electro-pneumatic cylinder is moved on a pump-cannula-specific trajectory. A friction and a valve model are adapted online. Verification and real world data show constant flow, low power consumption and the adherence of all limits.
A novel approach for increasing the traceability of 3D printed medical products
Authors: Matvieieva Nataliia , Neupetsch Constanze , Oettel Markus , Makdani Varun , Drossel Welf- Guntram 
Published: February 2021

Abstract
According to the European Medical Device Directive (MDR (EU) 2017/745), medical products of all risk classes are obliged to be labelled with Unique Device Identification Codes (UDI). In order to meet the requirements of the MDR, a novel method of identification for additively manufactured metallic products was developed at the Fraunhofer Institute for Machine Tools and Forming Technology (IWU). The method provides a product traceability within its production process and during the whole product lifespan, and also functions as a counterfeit protection. This paper shows the integration of a unique identification during an additive manufacturing process for a titanium part. The readout of the integrated identification was executed using ultrasonic and eddy current methods, as well as micro computed tomography. Obtained results are discussed in the paper.
Development of a realistic venepuncture phantom
Authors: Engers Marius , Stewart Kent W. , Liu Jan , Pott Peter P. 
Published: February 2021

Abstract
Venepuncture is one of the most common invasive procedures performed worldwide, however, complications still occur. Currently, commercial single layer silicone phantoms used for venepuncture training do not accurately imitate the geometry and mechanical properties seen in the various patient groups. This paper presents the development of a realistic artificial venepuncture phantom. Three multilayered tissue phantoms are developed simulating venepuncture sites of paediatric, adult and geriatric patients. Silicone materials of different stiffnesses were selected to imitate the epidermis, dermis, subcutaneous fat, muscle and superficial veins. Singleaxis indentation tests were carried out on silicone samples and the multi-layered phantom inserts to characterize the material properties. The measured Young's moduli for the artificial dermis, fat and muscle show sufficient agreement with corresponding literature values. However, characterization of the complete phantom inserts showed stiffnesses four times larger than prior in-vivo studies. Future studies will work on developing a more comparable in-vivo study.
DLP 3D printing of Dexamethasoneincorporated PEGDA-based photopolymers: compressive properties and drug release
Authors: Mau Robert , Reske Thomas , Eickner Thomas , Grabow Niels , Seitz Hermann 
Published: February 2021

Abstract
Photopolymerizing, high-resolution 3D printing methods such as Stereolithography (SLA) or Digital Light Processing (DLP) are very promising for the manufacturing of drug-incorporated, patient specific implants. However, a drug-load may be limited by adequately solubility of the active pharmaceutical ingredient (API) in the photopolymer. Furthermore, a drug-load may affect the mechanical properties of the material negatively. Here, we investigate the DLP 3D printing of drugincorporated photopolymers. Polyethylene glycol diacrylate (PEGDA, Mn = 700 g/mol) is used as matrix polymer and Dexamethasone (DEX) is used for drug-loading (10 g/L and 20 g/L). Compressive properties, drug release and drug stability of 3D printed test samples were analyzed. DEX was found to be sparingly soluble in the PEGDA-based photopolymer. Not all drug particles can be dissolved at a concentration of 20 g/L and a slurry-like suspension is formed. Drug-incorporated photopolymers of 10 g/L (solution) and 20 g/L (suspension) were processed successfully via DLP. The higher the drug-load, the lower the compressive strength. Mechanical properties can be improved via a post-curing in a UV light curing box. Drug-incorporated 3D printed test samples show burst-release of DEX. The post-curing process does not affect drug release. DEX degrades in 3D-printed test samples significantly (~ 30 %) over a several days time period.
Accelerated Degradation of polymeric surgical suture materials
Authors: Reske Thomas , Eickner Thomas , Grabow Niels , Schmitz Klaus-Peter , Siewert Stefan 
Published: February 2021

Abstract
The degradable polymer Polydioxanone (PDO) is used for medical implants since 1981. Manufacturers state a degradation timeframe of <180 days or an absorption duration of 182-238 days [1, 2]. Aim of this study was to find in vitro-conditions to degrade PDO films within four weeks. Therefore the degradation of PDO was performed in accelerated conditions in tempered alkaline glycine NaOH buffer. Molecular weight and mass loss were studied. PDO results were compared with poly lactic-co-glycolic acid P(LLA-co-GA).
Femoral Shape and Size Variability from segmented CT datasets for patient-specific THA planning
Authors: Fleischmann Christopher , Leher Irina , Sesselmann Stefan , Scherb David , Wolf Alexander , Miehling Jörg , Wartzack Sandro 
Published: February 2021

Abstract
Biomechanical functionality of artificial hips strongly correlates with quality of life of patients after total hip arthroplasty. As the numbers of total hip arthroplasty are growing due to increasing life expectancy, biomechanical research is of utmost importance to improve the implants used and the operative procedures applied. Multibody simulation is used to predict forces and moments inside the human body. Generic scaling is usually performed to adapt the human models used in multibody simulation to individual patients. However, since the shape and size of the bones can vary considerably, this type of scaling often is not sufficient. In this work various CT datasets were used to quantify differences of individual femoral shapes, especially with regard to important biomechanical hip parameters, such as the CCD angle or the femoral offset. Our results prove that multibody simulations should be modeled more patientspecific to be able to calculate articular forces and moments more precisely, and thus, to improve surgical planning.
Swipe up to smoke less cigarettes! Introducing a mobile Approach-Avoidance Task Application to fight Smoking
Authors: Eiler Tanja Joan , Haßler Benjamin , Grünewald Armin , Machulska Alla , Klucken Tim , Jahn Katharina , Niehaves Björn , Gethmann Carl Friedrich , Brück Rainer 
Published: February 2021

Abstract
Automatic tendencies to approach addictionrelated stimuli have been linked to the development and maintenance of harmful drug use behavior. Recent studies have shown that these automatic approaches can be directly addressed and modified by cognitive bias modification (CBM). However, the training and treatment effects are rather small and compliance could be impaired by time-consuming, multiple laboratory training sessions. Here we present a mobile variant of the Approach-Avoidance Task (app-AAT), which is evaluated by a feasibility study. The app-AAT is designed to improve the efficiency of CBM training by allowing smokers to access the training at any time, and by offering the option to track consumed cigarettes. Our first run with eight participants showed that the app was rated very positively with 4.2 out of 5 points (engagement: 3.7, functionality: 4.5, aesthetics: 4.4) by using the german Mobile App Rating Scale (MARS-G).
Workflow and Human-Centered Risk Analysis for Novel Mechatronic Rescue Aids I.
Authors: Drobinsky Sergey , Verjans Mark , Schleer Philipp , Kolk Benedikt , Bensiek Henrike , Radermacher Klaus , Janß Armin 
Published: February 2021

Abstract
Paramedics face rising numbers of deployments every year. As obstacles like stairs occur often, paramedics must frequently manually carry patients and are thereby exposed to loads multitudes higher than recommended. This creates the need for patient transport aids (PTA), which can physically support paramedics in a wide variety of transport situations, without slowing down the transport. In this paper a workflow analysis for transport missions in an urban context and basic tasks for PTAs are presented. Subsequently, the high-level task modelling and human-centered risk analysis according to the HiFEM method are presented for the use case of a patient transport over stairs with a passive PTA, like a rescue chair, and an active PTA like the novel SEBARES prototype. The analysis shows that conventional PTA’s have a simple linear use process, however, impose excessive physical workloads, which cause risks like the paramedic or the PTA falling down the stairs. Contrary, active PTA’s reduce physical workloads, however, introduce additional concurrent steps, like identifying and correcting misalignments, which create further risks. In order to mitigate risks with active, stair climbing PTAs either new kinematic designs or intelligent assistance functions, like automatic stair detection, are necessary.