bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of thermal treatment on the mechanical properties of PLLA tubular specimens
Authors: Arbeiter Daniela , Schümann K. , Sahmel O. , Eickner T. , Schmitz K.-P. , Grabow N. 
Published: December 2016

Abstract
Conventional permanent stent systems for vascular applications are associated with long-term risks, such as restenosis and thrombosis. To overcome these limitations, novel approaches using various biodegradable materials for stent construction have been investigated. In this context, thermal treatment of polymer materials is investigated to adjust the mechanical properties of biodegradable stents. In this work polymeric tubular specimens of biodegradable poly(L-lactide) (PLLA) were extruded and subjected to a molding process using different temperatures above glass transition temperature TG. Physicochemical properties of the molded samples were analyzed using DSC measurements and uniaxial tensile tests. The molding process resulted in a weakening of the PLLA tubular specimens with a simultaneous increase in the degree of crystallinity (χ).
Biocompatible wear-resistant thick ceramic coating
Authors: Vogt Nicola , Wozniak Katarzyna , Salito Armando , Wild Michael de 
Published: December 2016

Abstract
Sensitisation to immunologically active elements like chromium, cobalt or nickel and debris particle due to wear are serious problems for patients with metallic implants. We tested the approach of using a hard and thick ceramic coating as a wear-resistant protection of titanium implants, avoiding those sensitisation and foreign body problems. We showed that the process parameters strongly influence the coating porosity and, as a consequence, also its hardness.
Protection of active implant electronics with organosilicon open air plasma coating for plastic overmolding
Authors: Zeppenfeld Matthias , Wardenberg Maximilian , Rapp Christin , Eblenkamp Markus 
Published: December 2016

Abstract
To overcome challenges for manufacturing of modern smart medical plastic parts by injection molding, e.g. for active implants, the optimization of the interface between electronics and the polymer component concerning adhesion and diffusion behavior is crucial. Our results indicate that a nano-sized SiOxCyHz layer formed by plasma-enhanced chemical vapour deposition (PE-CVD) via open air atmospheric pressure plasma jet (APPJ) and by use of a hexamthyldisiloxane (HMDSO) precursor can form a non-corrosive, anti-permeable and biocompatible coating. Due to the open air character of the APPJ process an inline coating before overmolding could be an easy applicable method and a promising advancement.
Examination of dielectric strength of thin Parylene C films under various conditions
Authors: Heid Andreas , Metzen Rene von , Stett Alfred , Bucher Volker 
Published: December 2016

Abstract
The breakdown voltage of the biocompatible polymer Parylene C was determined after storage in 60°C saline solution and treatment by autoclave. It occurred that both, storage at 60°C in saline solution and autoclaving, lead to distinct decrease of dielectric strength by approximately 50%.
Open air plasma deposited antimicrobial SiOx/TiOx composite films for biomedical applications
Authors: Rapp Christin , Baumgärtel Andreas , Artmann Lucas , Eblenkamp Markus , Asad Syed Salman 
Published: December 2016

Abstract
Open air atmospheric pressure plasma jet (APPJ) enhanced chemical vapour deposition process was used to deposit biocompatible SiOx/TiOx composite coatings. The as deposited films are hydrophilic and show visible light induced photocatalytic effect, which is a consequence of the formation of defects in the TiOx structure due to the plasma process. This photocatalytic effect was verified by the demonstration of an antimicrobial effect under visible light on E. coli as well as by degradation of Rhodamine B. The films are non-cytotoxic as shown by the cytocompatibility tests. The films are conductive to cell growth and are stable in DMEM and isopropanol. The structural evaluation using SEM, EDS and XPS shows a dispersion of TiOx phase in a SiOxCyHz matrix. These analyses were used to correlate the structure-property relationship of the composite coating.
Systemic analysis about residual chloroform in PLLA films
Authors: Teske Michael , Arbeiter Daniela , Schober Konstanze , Eickner Thomas , Grabow Niels 
Published: December 2016

Abstract
Toxic volatile organic chemicals (VOCs), such as chloroform, are widely used in polymer manufacture in the field of implants and polymeric drug carriers. Several processes have to be carried out in order to remove toxic VOCs for patient safety without changing the thermal characteristics of the polymers. Therefore, we analyze the common commercial implant polymer poly(L-lactide) (PLLA) and screen different annealing- and rinsing processes considering influence on their morphology and thermal properties. For PLLA a rinsing step followed by annealing results in acceptable chloroform contents according to the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) recommendations. Annealing processes reveal the lowest chloroform content after one day, which did not further decrease significantly with extended annealing time.
A macrophage model of osseointegration
Authors: Jennissen Herbert P. 
Published: December 2016

Abstract
The mechanisms of peri-implant de novo bone formation and contact osteogenesis are still largely unknown. In 1984 Donath et al. showed that macrophages were the first cells to colonize a titanium implant. Recently it was shown that that there are inflammatory (M1) and healing macrophages (M2), the latter of which can secrete BMP 2. In the context of data from a gap healing experiment a macrophage model of osseointegration is suggested.
Technical concept and evaluation of a novel shoulder simulator with adaptive muscle force generation and free motion
Authors: Verjans Mark , Siroros Nad , Eschweiler Jörg , Radermacher Klaus 
Published: December 2016

Abstract
The human shoulder is one of the most complex joints of the human body, and due to the high range of motion and the complex soft tissue apparatus prone to injuries. Surgical therapies and joint replacements often lead to unsatisfactory results. To improve the understanding of the complex biomechanics of the shoulder, experimental investigations have to be conducted. For this purpose a new shoulder simulator with an innovative muscle force generation was developed. On the basis of a modular concept six artificial pneumatic muscles were integrated to represent the functionally most important muscles of the shoulder joint, whereby a free and controlled movement of the humerus can be conducted. For each muscle individual setpoints for muscle length control based on a user defined shoulder movement for any artificial or cadaver specimen are created by manual motion “Teach-In”. Additional to muscle forces and lengths, optical tracking and a joint force measurement is used to enable different biomechanical studies of the shoulder joint. This paper describes the technical setup as well as the control strategy and first results of its experimental functional validation.
Integration of a semi-automatic in-vitro RFA procedure into an experimental setup
Authors: Pollnow Stefan , Busch Lisa-Mareike , Wülfers Eike Moritz , Arnold Robert , Dössel Olaf 
Published: December 2016

Abstract
Radiofrequency ablation (RFA) is a standard clinical procedure for treating many cardiac arrhythmias. In order to increase the success rate of this treatment, the evaluation of lesion development with the help of intracardiac electrogram (EGM) criteria has to be improved further. We are investigating in-vitro the electrophysiological characteristics of cardiac tissue by using fluorescence-optical and electrical techniques. In this project, it is intended to create ablation lesions under defined conditions in rat atria or ventricle and to determine the electrical activity in the myocardium surrounding these lesions less than 1 s after the ablation. Therefore, we developed a semi-automatic RFA procedure, which was integrated into an existing experimental setup. Firstly, a controllable protection circuit board was designed to galvanically isolate the sensitive amplifiers for measuring extracellular potentials during the ablation. Secondly, a real-time system was implemented to control and to autonomously monitor the RFA procedure. We verified each component as well as the different sequences of the RFA procedure. In conclusion, the expanded setup will be used in future in-vitro experiments to determine new EGM criteria to assess lesion formation during the RFA procedure.
Fabrication of MEMS-based 3D-μECoG-MEAs
Authors: Deckert Martin , Lippert Michael , Takagaki Kentaroh , Brose Andreas , Ohl Frank , Schmidt Bertram 
Published: December 2016

Abstract
The microfabrication and packaging of novel, three-dimensional, polyimide-based, highly flexible, microscale electrocorticography multi-electrode arrays for enhanced epicortical recording of local field potentials is presented. A polyimide foil embeds metallic structures relating to 32 taper-type electrode sites, contact pads as well as interconnecting conductor paths which are integrated in the planar portion of the electrode substrate material. Circular exposed and, thus, active electrode sites are 50 μm in diameter and employed center-to-center pitches range from 250 μm to 1 mm, respectively. As-fabricated 3D-μECoG-MEAs provide taper heights of approximately 4 μm as well as 59 μm being distinguished by characteristic impedances of about 368.9 kΩ at 1 kHz measured in saline electrolyte. The applied packaging strategies favor flip-chip bonding and vapor phase soldering of the polymer substrates to customized printed circuit boards.
High speed digital interfacing for a neural data acquisition system
Authors: Bahr Andreas , Saleh Lait Abu , Schroeder Dietmar , Krautschneider Wolfgang H. 
Published: December 2016

Abstract
Diseases like schizophrenia and genetic epilepsy are supposed to be caused by disorders in the early development of the brain. For the further investigation of these relationships a custom designed application specific integrated circuit (ASIC) was developed that is optimized for the recording from neonatal mice [Bahr A, Abu-Saleh L, Schroeder D, Krautschneider W. 16 Channel Neural Recording Integrated Circuit with SPI Interface and Error Correction Coding. Proc. 9th BIOSTEC 2016. Biodevices: Rome, Italy, 2016; 1: 263; Bahr A, Abu-Saleh L, Schroeder D, Krautschneider W. Development of a neural recording mixed signal integrated circuit for biomedical signal acquisition. Biomed Eng Biomed Tech Abstracts 2015; 60(S1): 298–299; Bahr A, Abu-Saleh L, Schroeder D, Krautschneider WH. 16 Channel Neural Recording Mixed Signal ASIC. CDNLive EMEA 2015 Conference Proceedings, 2015.]. To enable the live display of the neural signals a multichannel neural data acquisition system with live display functionality is presented. It implements a high speed data transmission from the ASIC to a computer with a live display functionality. The system has been successfully implemented and was used in a neural recording of a head-fixed mouse.
Portable auricular device for real-time swallow and chew detection
Authors: Steimer Konrad C. , Zimmermann Christoph , Zeilfelder Jennifer , Pylatiuk Christian , Stork Wilhelm 
Published: December 2016

Abstract
Monitoring a person’s nutritional consumption is costly and complex. To solve this problem a new technique is proposed to draw conclusions of a person’s food intake. The air pressure signal, recorded in the external acoustic meatus, is used to detect swallow and chew events. A portable device has been developed to record this pressure signal. Due to the constraint of running on a low-power microcontroller, real-time algorithms, used in pattern and speech recognition, were used to develop methods to automatically detect swallow and chew events. A binary classifier was trained by means of manually annotated data sets. Direct comparisons with state of the art technology and tests with several subjects are provided for evaluation purposes.
Detection of miRNA using a surface plasmon resonance biosensor and antibody amplification
Authors: Schmieder Stefan , Weißpflog Janek , Danz Norbert , Klotzbach Udo , Sonntag Frank 
Published: December 2016

Abstract
MiRNAs are non-coding RNA molecules that control biological functions by reducing the translation of target proteins when binding to the mRNA. Alterations of the miRNA expression profile affect the cell metabolism, which can lead to distinctive disease patterns thus suggesting miRNA as an interesting biomarker. Here we present a SPR biosensor that utilizes disposable, injection-molded sensor chip/microfluidic hybrids combined with a lateral imaging optical system for parallel analysis of three one-dimensional spot arrays to detect miRNA-93. Using a RNA-DNA-hybrid antibody for signal enhancement we could reach a limit of detection of 10 pmol/l.
Simulation and evaluation of stimulation scenarios for targeted vestibular nerve excitation
Authors: Schier Peter , Handler Michael , Baumgarten Daniel , Baumgartner Christian 
Published: December 2016

Abstract
Recent studies show that vestibular implants have the potential to compensate the loss of functionality of the organ of equilibrium. The objective of this study was the development of a simulation framework which estimates the capability of various electrode arrangements and stimulation waveforms to selectively excite the ampullary nerves in the vestibular system. The choice of electrode configuration and stimulation waveform shows a significant influence in resulting selectivity, energy expenditure and injected charge in our simulations. This simulation environment could be beneficial in the development of safe and selective stimulation electrode designs.
Classification of cardiac excitation patterns during atrial fibrillation
Authors: Reich Christian , Oesterlein Tobias , Rottmann Markus , Seemann Gunnar , Dössel Olaf 
Published: December 2016

Abstract
The goal of this research was to classify cardiac excitation patterns during atrial fibrillation (AFib). For this purpose, virtual models of intracardiac mapping catheters were moved across in-silico cardiac tissue to extract local activation times (LATs) of each catheter electrode from simulated cardiac action potential (AP) signals. The resulting LAT patterns consisting of the LATs of all electrodes resemble patterns measured in clinical cases. The LATs represent the input information for features that were used to separate four different excitation patterns during AFib. Those four excitation patterns were plane wave, ectopic focus (spherical wave), rotor (spiral wave) and block. A feature selection algorithm was used to investigate the features concerning their power to classify the different simulated excitation patterns. The scores of the selected features were used to train and optimize a support vector machine (SVM). The optimized and cross-validated SVM was then used to classify the simulated cardiac excitation patterns. The achieved overall classification accuracy of this SVM model was 98.4 %.
An algorithm to automatically determine the cycle length coverage to identify rotational activity during atrial fibrillation – a simulation study
Authors: Kaltenbacher Wenzel , Rottmann Markus , Dössel Olaf 
Published: December 2016

Abstract
Atrial fibrillation is the most common cardiac arrhythmia. Many physicians believe in the hypothesis that persistent atrial fibrillation is maintained by centers of rotatory activity. These so called rotors are sometimes found by physicians during catheter ablation or electrophysiological studies but there are also physicians who claim that they did not find any rotors at all. One reason might be that today rotors are mainly identified by visual inspection of the data. Thus we are aiming at an algorithm for rotor detection. We first developed an algorithm based on the local activation times of the intracardiac electrograms recorded by a multielectrode catheter that can automatically determine the cycle length coverage. This was done to get an objective view on possible rotors and therefore help to quantify whether a rotor was found or not. The algorithm was developed and evaluated in two different simulation setups, where it could reliably determine cycle length coverage. But we found out that effects like wave collision and slow conduction have strong influence on cycle length coverage. This prevents cycle length coverage from being suited as the only parameter to quantify whether a rotor is present or not. On the other hand we could confirm that rotors imply a cycle length coverage of >70% if the multielectrode catheter is centered in an area of <5 mm away from the rotor tip. Therefore cycle length coverage can at least be used in some situations to exclude the presence of possible rotors.
Deriving respiration from high resolution 12-channel-ECG during cycling exercise
Authors: Schumann Andy , Schmidt Marcus , Herbsleb Marco , Semm Charlotte , Rose Georg , Gabriel Holger , Bär Karl-Jürgen 
Published: December 2016

Abstract
Monitoring of cardiac and respiratory activity, is essential in several clinical interventions like bicycle ergometries. The respiration signal can be derived from the ECG if it is not recorded itself (ECG derived respiration, EDR). In this study, we tried to reconstruct breathing rates (BR) from stress test high resolution 12-channel-ECGs in nine healthy subjects using higher order central moments. A mean absolute error per subjects of 2.9/min and relatively high correlation (r
p
= 0.85) and concordance coefficient (rc = 0.79) indicated a quite accurate reproduction of respiratory activity. The analysis of the different test stages revealed an increase of BR errors while subjects were effortful cycling compared to rest. During incremental cycling exercise test the mean absolute error per subjects was 3.4/min. Compared to the results reported in other studies at rest in supine position, this seems adequately accurate. In conclusion, our results indicate that EDR using higher order central moments is suited for monitoring BR during physical activity.
Postprocessing algorithm for automated analysis of pelvic intraoperative neuromonitoring signals
Authors: Wegner Celine , Krueger Thilo B. , Hoffmann Klaus-Peter , Kauff Daniel W. , Kneist Werner 
Published: December 2016

Abstract
Two dimensional pelvic intraoperative neuromonitoring (pIONM®) is based on electric stimulation of autonomic nerves under observation of electromyography of internal anal sphincter (IAS) and manometry of urinary bladder. The method provides nerve identification and verification of its’ functional integrity. Currently pIONM® is gaining increased attention in times where preservation of function is becoming more and more important. Ongoing technical and methodological developments in experimental and clinical settings require further analysis of the obtained signals. This work describes a postprocessing algorithm for pIONM® signals, developed for automated analysis of huge amount of recorded data. The analysis routine includes a graphical representation of the recorded signals in the time and frequency domain, as well as a quantitative evaluation by means of features calculated from the time and frequency domain. The produced plots are summarized automatically in a PowerPoint presentation. The calculated features are filled into a standardized Excel-sheet, ready for statistical analysis.
Efficient design of FIR filter based low-pass differentiators for biomedical signal processing
Authors: Wulf Michael , Staude Gerhard , Knopp Andreas , Felderhoff Thomas 
Published: December 2016

Abstract
This paper describes an alternative design of linear phase low-pass differentiators with a finite impulse response (type III FIR filter). To reduce the number of necessary filter coefficients, the differentiator’s transfer function is approximated by a Fourier series of a triangle function. Thereby the filter’s transition steepness towards the stopband is intentionally reduced. It can be shown that the proposed design of low-pass differentiators yields to similar results as other published design recommendations, while the filter order can be significantly reduced.
Nonlinear causal influences assessed by mutual compression entropy
Authors: Schumann Andy , Fleckenstein Berit , Bär Karl-Jürgen 
Published: December 2016

Abstract
Autonomic control of the heart rate was demonstrated to be complex and nonlinear. Respiratory sinus arrhythima plays a crucial role in heart rate vagal modulation. Here we present an approach of assessing nonlinear causal relationships in bivariate time series, called mutual compression entropy (MCE). We applied MCE to cardiorespiratory data of 29 patients with acute schizophrenia and 29 matched controls. The method is based on data compression and estimates to which extend a (target) time series can be compressed regarding another time series (driver). In schizophrenia an elevated sympathetic and reduced parasympathetic heart rate modulation was found. The nonlinear influence of respiration on heart rate variability was demonstrated by a highly significant reduction of MCE (0.816 vs. 0.808, p¡0.01). In healthy subjects MCE was mainly related to sympathovagal balance. We conclude, that this index has the potential to uncover physiological information beyond linear measures.
Comparative study of methods for solving the correspondence problem in EMD applications
Authors: Piper Diana , Schiecke Karin , Witte Herbert , Leistritz Lutz 
Published: December 2016

Abstract
We address the correspondence problem which arises when applying empirical mode decomposition (EMD) to multi-trial and multi-subject data. EMD decomposes a signal into a set of narrow-band components named intrinsic mode functions (IMFs). The number of IMFs and their signal properties can be different between trials, channels and subjects. In order to assign IMFs with similar characteristics to each other, we compare two assignment methods, unbalanced assignment and k-cardinality assignment and two clustering algorithms, namely hierarchical clustering and density-based spatial clustering of applications with noise based on heart rate variability data of children with temporal lobe epilepsy.
fNIRS for future use in auditory diagnostics
Authors: Bauernfeind Günther , Haumann Sabine , Lenarz Thomas 
Published: December 2016

Abstract
Functional near-infrared spectroscopy (fNIRS) is an emerging technique for the assessment of functional activity of the cerebral cortex. Recently fNIRS was also envisaged as a novel neuroimaging approach for measuring the auditory cortex (AC) activity in cochlear implant (CI) users. In the present study we report on initial measurements of AC activation due to spatial sound presentation with a first target to generate data for comparison with CI user and the future use in auditory diagnostics.
Left cardiac atrioventricular delay and inter-ventricular delay in cardiac resynchronization therapy responder and non-responder
Authors: Heinke Matthias , Kühnert Helmut , Heinke Tobias , Tumampos Jonas , Dannberg Gudrun 
Published: December 2016

Abstract
Cardiac resynchronization therapy is an established therapy for heart failure patients. The aim of the study was to evaluate electrical left cardiac atrioventricular delay and interventricular desynchronization in sinus rhythm cardiac resynchronization therapy responder and non-responder. Cardiac electrical desynchronization were measured by surface ECG and focused transesophageal bipolar left atrial and left ventricular ECG before implantation of cardiac resynchronization therapy defibrillators. Preoperative electrical cardiac desynchronization was 195.7 ± 46.7 ms left cardiac atrioventricular delay and 74.8 ± 24.5 ms interventricular delay in cardiac resynchronization therapy responder. Cardiac resynchronization therapy responder New York Heart Association class improved during long term biventricular pacing. Transesophageal left cardiac atrioventricular delay and interventricular delay may be additional useful parameters to improve patient selection for cardiac resynchronization therapy.