bluuebunny/crossref_metadata_2025_split huggingface dataset:
Image acquisition and planimetry systems to develop wounding techniques in 3D wound model
Authors: Kiefer Ann-Kathrin , Parente Jacquelyn Dawn , Hensler Sabine , Mueller Margareta M. , Moeller Knut 
Published: September 2017

Abstract
Wound healing represents a complex biological repair process. Established 2D monolayers and wounding techniques investigate cell migration, but do not represent coordinated multi-cellular systems. We aim to use wound surface area measurements obtained from image acquisition and planimetry systems to establish our wounding technique and in vitro organotypic tissue. These systems will be used in our future wound healing treatment studies to assess the rate of wound closure in response to wound healing treatment with light therapy (photobiomodulation). The image acquisition and planimetry systems were developed, calibrated, and verified to measure wound surface area in vitro. The system consists of a recording system (Sony DSC HX60, 20.4 M Pixel, 1/2.3″ CMOS sensor) and calibrated with 1mm scale paper. Macro photography with an optical zoom magnification of 2:1 achieves sufficient resolution to evaluate the 3mm wound size and healing growth. The camera system was leveled with an aluminum construction to ensure constant distance and orientation of the images. The JPG-format images were processed with a planimetry system in MATLAB. Edge detection enables definition of the wounded area. Wound area can be calculated with surface integrals. To separate the wounded area from the background, the image was filtered in several steps. Agar models, injured through several test persons with different levels of experience, were used as pilot data to test the planimetry software. These image acquisition and planimetry systems support the development of our wound healing research. The reproducibility of our wounding technique can be assessed by the variability in initial wound surface area. Also, wound healing treatment effects can be assessed by the change in rate of wound closure. These techniques represent the foundations of our wound model, wounding technique, and analysis systems in our ongoing studies in wound healing and therapy.
Closed-loop control system for well-defined oxygen supply in micro-physiological systems
Authors: Steege Tobias , Busek Mathias , Grünzner Stefan , Lasagni Andrés Fabían , Sonntag Frank 
Published: September 2017

Abstract
To improve cell vitality, sufficient oxygen supply is an important factor. A deficiency in oxygen is called Hypoxia and can influence for example tumor growth or inflammatory processes. Hypoxia assays are usually performed with the help of animal or static human cell culture models. The main disadvantage of these methods is that the results are hardly transferable to the human physiology. Microfluidic 3D cell cultivation systems for perfused hypoxia assays may overcome this issue since they can mimic the in-vivo situation in the human body much better. Such a Hypoxia-on-a-Chip system was recently developed. The chip system consists of several individually laser-structured layers which are bonded using a hot press or chemical treatment. Oxygen sensing spots are integrated into the system which can be monitored continuously with an optical sensor by means of fluorescence lifetime detection.
Hereby presented is the developed hard- and software requiered to control the oxygen content within this microfluidic system. This system forms a closed-loop control system which is parameterized and evaluated.
Mutual influence of incorporated drugs in a dual drug delivery coating for cardiovascular applications
Authors: Wulf Katharina , Teske Michael , Matschegewski Claudia , Arbeiter Daniela , Eickner Thomas , Schmitz Klaus-Peter , Grabow Niels 
Published: September 2017

Abstract
For a long-term efficient drug-eluting stent for vascular applications, the development of drug-loaded coating, combining the effective inhibition of smooth muscle cell proliferation while promoting the re-endothelialization, is a promising concept. However the mostly required simultaneous incorporation of drugs can influence decisively the stability, efficacy and release of the respective drug. Therefore, the mutual influence of a dual local drug delivery coatings based on poly(L-lactide-co-ε-caprolactone) (PLLA-co-CL) containing vascular endothelial growth factor (VEGF165) coupled to the surface and an embedded drug, such as fluorescein diacetate (FDAc) instead of Paclitaxel (PTX) on the in vitro drug release was investigated. Surprisingly, for the investigated coating the immobilized VEGF loading was enhanced and the release profile was accelerated by FDAc incorporation. Even a manifold increase for the in vitro released amounts of VEGF was detected. In contrast, the immobilization of VEGF seems to have a negligible influence on the in vitro FDAc release profiles.
Glycerol gelatin for 3D-printing of implants using a paste extrusion technique
Authors: Kempin Wiebke , Baden Anna , Weitschies Werner , Seidlitz Anne 
Published: September 2017

Abstract
Fused deposition modeling as an additive manufacturing technique has gained great popularity for the fabrication of medical devices as well as pharmaceutical dosage forms over the last years. Particularly the variety of geometries that can be printed determines the attractiveness of this technique enabling a shape adaption of e.g. implants. In the presented work the soft hydrogel material glycerol gelatin was investigated towards its applicability in 3D-printing as an alternative to the commonly applied and mostly rigid polyesters. Model implants loaded with the model drug quinine and with the shape of a hollow cylinder were printed via an extrusion based technique utilizing the piston feed in a hydrogel filled heatable syringe. Glycerol gelatin hydrogels need to be crosslinked to avoid gel-sol-transition at body temperature. For this purpose three different crosslinking methods (insertion, dipping, spraying) with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) were evaluated regarding their crosslinking efficiency and drug losses during the crosslinking process. Dipping of the implant into an aqueous solution with at least 50 mM EDC and 10 mM NHS was found to be the most efficient crosslinking technique in conjunction with a smaller drug loss during processing compared to inserting. However, the use of hydrogels also causes problems as an intense and highly variable swelling of the printed structures during crosslinking (120.7 % ± 11.9 % for 10 times dipping in 50mM EDC/10 mM NHS) and a great dependency of the volume on storage conditions complicate the preparation of tailor-made implants. The release of the model drug quinine from printed and crosslinked implants was fast and nearly completed within 6 hours.
Fabrication and electrochemical characterization of ruthenium nanoelectrodes
Authors: Allani Sonja , Jupe Andreas , Figge Martin , Goehlich Andreas , Vogt Holger 
Published: September 2017

Abstract
The Fraunhofer IMS has recently developed a technique for producing nanoelectrodes that are generated by atomic layer deposition (ALD) in a via deep reactive ion etching (DRIE) structured sacrificial layer. This method enables the fabrication of CMOS- and biocompatible nanoelectrodes with suitable ALD-materials. Improvements of the established fabrication processes and the electrochemical characterization of such electrodes are presented. In the frame of the Fraunhofer-Max-Planckcooperation project ZellMOS different types of nanoelectrodes are studied. Their diameter is in the range of 200 nm and thereby sufficiently small to be taken up by living cells. In addition, the electrodes are mechanically enforced by an oxide layer at the nanoelectrodes’ bottom.
Stopping power accuracy and achievable spatial resolution of helium ion imaging using a prototype particle CT detector system
Authors: Volz Lennart , Collins-Fekete Charles-Antoine , Piersimoni Pierluigi , Johnson Robert P. , Bashkirov Vladimir , Schulte Reinhard , Seco Joao 
Published: September 2017

Abstract
A precise relative stopping power map of the patient is crucial for accurate particle therapy. Charged particle imaging determines the stopping power either tomographically – particle computed tomography (pCT) – or by combining prior knowledge from particle radiography (pRad) and x-ray CT. Generally, multiple Coulomb scattering limits the spatial resolution. Compared to protons, heavier particles scatter less due to their lower charge/mass ratio. A theoretical framework to predict the most likely trajectory of particles in matter was developed for light ions up to carbon and was found to be the most accurate for helium comparing for fixed initial velocity. To further investigate the potential of helium in particle imaging, helium computed tomography (HeCT) and radiography (HeRad) were studied at the Heidel-berg Ion-Beam Therapy Centre (HIT) using a prototype pCT detector system registering individual particles, originally developed by the U.S. pCT collaboration. Several phantoms were investigated: modules of the Catphan QA phantom for analysis of spatial resolution and achievable stopping power accuracy, a paediatric head phantom (CIRS) and a custom-made phantom comprised of animal meat enclosed in a 2 % agarose mixture representing human tissue. The pCT images were reconstructed applying the CARP iterative reconstruction algorithm. The MTF10% was investigated using a sharp edge gradient technique. HeRad provides a spatial resolution above that of protons (MTF1010%=6.07 lp/cm for HeRad versus MTF10%=3.35 lp/cm for proton radiography). For HeCT, the spatial resolution was limited by the number of projections acquired (90 projections for a full scan). The RSP accuracy for all inserts of the Catphan CTP404 module was found to be 2.5% or better and is subject to further optimisation. In conclusion, helium imaging appears to offer higher spatial resolution compared to proton imaging. In future studies, the advantage of helium imaging compared to other imaging modalities in clinical applications will be further explored.
Correlation between germ and particle measurements for the qualification of ventilation systems in the OR
Authors: Bulitta Clemens , Walberer Laura , Buhl Sebastian 
Published: September 2017

Abstract
Healthcare associated infections in surgical procedures have long been the focus of scientific research. In Germany, more than 225,000 patients suffer from such infections each year [1]. However, the reduction of the microbiological contamination is not only limited by cleaning and disinfecting measures. The choice of the ventilation system in the operating room or the type of the clothing of the personnel during the operation is also an important factor contributing to patient safety and infection control. Currently there are different approaches for assessing the hygienic situation in an operating room. In Germany, the air quality and cleanliness is evaluated by the DIN 1946-4: 2008-12 [2] and is based on the measurement of particles in the operating theatre. Other countries i.eSweden. focus on the biological contamination and use microbiological methods for the assessment and surveillance of the operating room ventilation (SIS-TS 39: 2015) [3].
Verification of on-demand medical device networks
Authors: Dingler Max , Dietz Christian , Lüth Tim 
Published: September 2017

Abstract
We propose a novel method for the automated formal analysis of on-demand medical device networks communicating via an open communication protocol. The resulting toolbox aims at assisting operators of cross-vendor medical device networks in the complex process of conformity assessment. The method is based on the notion of timed, extended finite automata and employs existent TCTL model checking techniques by use of MATLAB and UPPAAL. We evaluate our methodology in a real-life application similar to a user experience published by the U.S. Food and Drug Admninistration. The method revealed a flaw in the connector design for the Surgical Real Time Bus of the OR.Net project.
Information management for enabling systems medicine
Authors: Ganzinger Matthias , Knaup Petra 
Published: September 2017

Abstract
Systems medicine is a data-oriented approach in research and clinical practice to support study and treatment of complex diseases. It relies on well-defined information management processes providing comprehensive and up to date information as basis for electronic decision support. The authors suggest a three-layer information technology (IT) architecture for systems medicine and a cyclic data management approach including a knowledge base that is dynamically updated by extract, transform, and load (ETL) procedures. Decision support is suggested as case-based and rule-based components. Results are presented via a user interface to acknowledging clinical requirements in terms of time and complexity. The systems medicine application was implemented as a prototype.
Distinguishability and identifiability of products with small bore connectors according to ISO DIS 80369 series: risk analysis and summative evaluation
Authors: Ibenthal Elisabeth , Hölscher Uvo M. , Backhaus Claus 
Published: September 2017

Abstract
The ISO 80369-series replace Luer-connectors in five application areas to fight misconnections. Although the standard avoids the mechanical problem of misconnections, the design of products and packages remains arbitrary. So, packages and products with same functions but different connectors could have similar designs and hence could be mixed-up.
To ascertain whether standardization is needed for marking non-distinguishable products and packages, a risk management and usability engineering process were carried out, partly.
The ensuing risk analysis created nine unacceptable risks relating to non-distinguishable packages and lookalike-products. Based on this, risk control (standardization) is needed for lookalikes with the following proposed measures: colour allocation and haptic textures for products, colour allocation and symbols for packages. Furthermore, three scenarios were planned for summative evaluation.
An additional consideration of the efficiency of proposed combinations of measures and products relying on measures would be helpful.
Impact of aortic root geometry on hydrody-namic performance of transcatheter aortic valve prostheses
Authors: Kaule Sebastian , Pfensig Sylvia , Ott Robert , Siewert Stefan , Grabow Niels , Schmitz Klaus-Peter , Stiehm Michael 
Published: September 2017

Abstract
Assessment of hydrodynamic performance of transcatheter aortic valve prostheses (TAVP) in vitro is es-sentially in the fields of development and approval of novel implants. For the prediction of clinical performance, in vitro testing of TAVP allows for benchmarking of different devic-es, likewise. In addition to the implant itself, also the testing environment has a crucial influence on leaflet dynamics and quantitative test results like effective orifice area (EOA) or aortic regurgitation.
Therefore, within the current study we developed simpli-fied physiological and pathophysiological vessel models of the aortic root as a tool for in vitro hydrodynamic testing of TAVP in idealized and worst case conditions. We used 3D printing and silicone cast molding for manufacturing of aortic root models with variable degree of stenosis. Design of aortic roots with normal, mild and severe stenosis was developed according to Reul et al. For manufacturing of tripartite cast-ing molds, a 3D printer was used. Both outer mold parts and the mold core were manufactured from polylactide filament and water soluble polyvinylalcohol filament, respectively. In vitro hydrodynamic performance testing of an exemplary commercially available TAVP implanted in different aortic root models was conducted according to DIN EN ISO 5840-3:2013, using a pulse duplicator system. Manufactured aortic root models were highly transparent, dimensionally stable and therefore suitable for hydrodynamic testing of TAVP. Both, EOA and regurgitant fraction in-creased with increasing degree of stenosis from 1.6 ± 0.1 cm2 to 1.8 ± 0.1 cm2 and 8.6 ± 6.5% to 20.2 ± 4.2% (n = 30 cy-cles), respectively.
We successfully developed a testing environment ena-bling sophisticated evaluation of hydrodynamic performance of TAVR in pathophysiological worst case conditions.
Tissue-specific transformation model for CT-images
Authors: Bartelheimer Kathrin , Teske Hendrik , Bendl Rolf , Giske Kristina 
Published: September 2017

Abstract
During radiotherapy, posture changes and volume changing deformations like growing or shrinking tissue result in anatomical deformations. The basis for investigating the impact of such deformations on dose uncertainties, are model-based tools for deformation analysis. In this context, we propose a transformation model based on the information of CT-images, which allows an on-the-fly calculation of voxel volumes. Our model is based on the concept of the chainmail algorithm and describes deformation on voxel-level. With an exemplary input of a set of landmark pairs, generated by a kinematic head-and-neck skeleton model, CT-images (512x512x126 voxel) can be deformed with an on-the-fly volume calculation in less than 70s. The volume calculation delivers insight into model-characteristic volume changes and is a prerequisite for implementing tissue growth and shrinkage.
Experimental validation of a bias in apparent exchange rate measurement
Authors: Ulloa Patricia , Methot Vincent , Koch Martin A. 
Published: September 2017

Abstract
Double diffusion encoding (DDE) MRI is a technique in which two diffusion weighted periods are applied between excitation and acquisition. This allows to acquire structural information (as pore size and shape) and molecular exchange between compartments, in terms of apparent exchange rate (AXR). However, it has not been well investigated yet whether the diffusion restriction underlying DDE size estimation may compromise AXR results.
Numerical simulations for impermeable spheres have shown that in case of small pores (diameter < 10 μm) the restriction effect may be neglected. Yet, for larger pores, the restriction effect can be relevant and needs to be considered in the analysis of experiments.
Here, we present experiments performed on a 3 T clinical MRI system using a water-in-oil emulsion in which no exchange between compartments is expected. The results show that a nonzero apparent exchange rate may be estimated in a sample with impermeable pores. This shows that, as predicted in simulations, the restriction effect affects the AXR results. The use of perpendicular diffusion gradients may be a solution for this problem in isotropic samples.
Comparing human and algorithmic tracking of subviral particles in fluorescence microscopic image sequences
Authors: Müller Dennis , Rausch Andreas , Dolnik Olga , Schanze Thomas 
Published: September 2017

Abstract
Tracking of subviral particles with automated methods enables the analysis of intracellular processes exhibited by viruses. A linear assignment problem solver and a Kalman-filter have been added to an existing particle tracking algorithm. First results produced with simulated image sequences showed that the improved algorithm is able to improve tracking results by closing gaps in the particle’s trajectories. Here we report on the evaluation of the LAP-Kalman algorithm using real fluorescence-microscopic images. The results from the original and improved algorithm have been compared to the results of manual tracking. Evaluation results indicate that the improved algorithm is capable to reconstruct missing parts of particle tracks in difficult conditions. However, the evaluation of the algorithms and the manual tracking is a complex task because of the low image contrast and high object density with intersecting tracks in the live-cell images.
Drowsiness discrimination in an overnight driving simulation on the basis of RR and QT intervals
Authors: Heinze Christian , Hütterer Constantin , Schnupp Thomas , Lenis Gustavo , Golz Martin 
Published: September 2017

Abstract
We examined if ECG-based features are discrimi-native towards drowsiness. Twenty-five volunteers (19–32 years) completed 7×40 minutes of monotonous overnight driving simulation, designed to induce drowsiness. ECG (512 s-1) was recorded continuously; subjective ratings of drowsiness on the Karolinska sleepiness scale (KSS) were polled every five minutes. ECG recordings were divided into 5-min segments, each associated with the mean of one self- and two observer-KSS ratings. Those mean KSS values were binarized to obtain two classes not drowsy and drowsy. The Q-, R- and T-waves in the recordings were detected; R-peak positions were manually reviewed; the Q- and T-detection method was tested against the manual annotations of Physio-net’s QT database. Power spectral densities of RR intervals (RR-PSD) and quantiles of the empirical distribution of heart-rate corrected QTc intervals were estimated. Support-vector machines and random-holdout cross-validation were used for the estimation of the classification error. Using either RR-PSD or QTc features yielded mean test errors of 79.3 ± 0.3 % and 82.7 ± 0.5 %, respectively. Merging RR and QTc features improved the accuracy to 88.3 ± 0.2 %. QTc intervals of the class drowsy were generally prolonged com-pared to not drowsy. Our findings indicate that the inclusion of QT intervals contribute to the discrimination of driver sleepiness.
Circadian rhythmicity of cognitive performance
Authors: Schnupp Thomas , Heinze Christian , Golz Martin 
Published: September 2017

Abstract
It was investigated whether cognitive performance shows a circadian rhythm during a 50 h-long forced desynchrony sleep-wake-schedule. We asked whether it would be possible to estimate the circadian period of cognitive performance under such circumstances and how strong it correlates to subjective sleepiness rating as well as body temperature.
Cognitive performance was evaluated using the Bowles-Langley test (BLT), which estimates cognitive performance by capturing reaction time and counting errors in a 2-choice visual search task.
Power spectral densities (PSD) were estimated by the Lomb-Scargle periodogram [1]. The circadian period τc
was estimated from peak PSD. PSD of BLT scores showed lowest, yet distinct, circadian amplitude.
In addition to the circadian period estimation we analyzed the correlation of the acquired variables against each other. Pearson’s correlation coefficients were significant but varied strongly at a commonly low level.
Despite the obstacle of a plethora of influencing factors [2] BLT scores are sensitive to the circadian rhythm and provide correct estimates of τc
compared to rectal body temperature (RBT) as reference. Subjective measures failed estimating τc
.
Deriving kinematic quantities from accelerometer readings for assessment of functional upper limb motions
Authors: Laidig Daniel , Seel Thomas 
Published: September 2017

Abstract
Wearable accelerometers are lightweight, affordable, and allow for even smaller form factors than 9D inertial measurement units. They are therefore a promising tool for assessing the quality of movement of patients during daily life activities. While generic signal features such as signal power and frequency content are widely used, the derivation of kinematic (angular and spatial) quantities remains a challenge. We consider a chain of body segments, such as the arm, equipped with 3D accelerometers and propose a method for calculation of the inclination and relative height of the distal segment. For validation of the method against an optical motion capture system, we consider a setup with accelerometers on the forearm and the upper arm of a subject, who performs a sequence of drinking motions and pick-and-place motions. We obtain a root-mean-square deviation of about 2.5 cm for the wrist height relative to the shoulder and about 6° for the inclination angles of the forearm. We conclude that the proposed method yields measurements of kinematic quantities that are accurate enough for classification of functional versus non-functional motions or well-performed motions versus incomplete motions.