TY - JOUR A1 - Doll, Theodor A1 - Wagner, Torsten A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Engineering of functional interfaces / Theodor Doll ; Torsten Wagner ; Patrick Wagner ; Michael J. Schöning (eds.) JF - Physica status solidi (a) Y1 - 2016 U6 - https://doi.org/10.1002/pssa.201670641 SN - 1862-6319 VL - 213 IS - 6 SP - 1393 EP - 1394 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Kolditz, Melanie A1 - Albin, Thivaharan A1 - Abel, Dirk A1 - Fasse, Alessandro A1 - Brüggemann, Gert-Peter A1 - Albracht, Kirsten T1 - Evaluation of foot position and orientation as manipulated variables to control external knee adduction moments in leg extension training JF - Computer methods and programs in biomedicine N2 - Background and Objective Effective leg extension training at a leg press requires high forces, which need to be controlled to avoid training-induced damage. In order to avoid high external knee adduction moments, which are one reason for unphysiological loadings on knee joint structures, both training movements and the whole reaction force vector need to be observed. In this study, the applicability of lateral and medial changes in foot orientation and position as possible manipulated variables to control external knee adduction moments is investigated. As secondary parameters both the medio-lateral position of the center of pressure and the frontal-plane orientation of the reaction force vector are analyzed. Methods Knee adduction moments are estimated using a dynamic model of the musculoskeletal system together with the measured reaction force vector and the motion of the subject by solving the inverse kinematic and dynamic problem. Six different foot conditions with varying positions and orientations of the foot in a static leg press are evaluated and compared to a neutral foot position. Results Both lateral and medial wedges under the foot and medial and lateral shifts of the foot can influence external knee adduction moments in the presented study with six healthy subjects. Different effects are observed with the varying conditions: the pose of the leg is changed and the direction and center of pressure of the reaction force vector is influenced. Each effect results in a different direction or center of pressure of the reaction force vector. Conclusions The results allow the conclusion that foot position and orientation can be used as manipulated variables in a control loop to actively control knee adduction moments in leg extension training. KW - External knee adduction moments KW - Manipulated variables KW - Inverse dynamic problem KW - Inverse kinematic problem KW - Musculoskeletal model Y1 - 2016 U6 - https://doi.org/10.1016/j.cmpb.2016.09.005 SN - 0169-2607 N1 - Part of special issue: "SI: Personalised Models and System Identification" VL - 171 SP - 81 EP - 86 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Belavy, Daniel L. A1 - Albracht, Kirsten A1 - Bruggemann, Gert-Peter A1 - Vergroesen, Pieter-Paul A. A1 - Dieen, Jaap H. van T1 - Can exercise positively influence the intervertebral disc? JF - Sports Medicine N2 - To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a narrative review. The majority of the available data come from cell or whole-disc loading models and animal exercise models. However, some studies have examined the impact of specific sports on IVD degeneration in humans and acute exercise on disc size. Based on the data available in the literature, loading types that are likely beneficial to the IVD are dynamic, axial, at slow to moderate movement speeds, and of a magnitude experienced in walking and jogging. Static loading, torsional loading, flexion with compression, rapid loading, high-impact loading and explosive tasks are likely detrimental for the IVD. Reduced physical activity and disuse appear to be detrimental for the IVD. We also consider the impact of genetics and the likelihood of a ‘critical period’ for the effect of exercise in IVD development. The current review summarises the literature to increase awareness amongst exercise, rehabilitation and ergonomic professionals regarding IVD health and provides recommendations on future directions in research. KW - Intradiscal Pressure KW - Annulus Fibrosus KW - Disc Degeneration KW - Nucleus Pulposus KW - Intervertebral Disc Y1 - 2016 U6 - https://doi.org/10.1007/s40279-015-0444-2 SN - 1179-2035 VL - 46 IS - 4 SP - 473 EP - 485 PB - Springer CY - Berlin ER - TY - JOUR A1 - Seynnes, O. R. A1 - Bojsen-Moller, J. A1 - Albracht, Kirsten A1 - Arndt, A. A1 - Cronin, N. J. A1 - Finni, T. A1 - Magnusson, S. P. T1 - Ultrasound-based testing of tendon mechanical properties: a critical evaluation JF - Journal of Applied Physiology Y1 - 2015 U6 - https://doi.org/10.1152/japplphysiol.00849.2014 SN - 8750-7587 VL - 118 IS - 2 SP - 133 EP - 141 ER - TY - JOUR A1 - Albracht, Kirsten A1 - Arampatzis, Adamantios T1 - Exercise-induced changes in triceps surae tendon stiffness and muscle strength affect running economy in humans JF - European Journal of Applied Physiology Y1 - 2013 U6 - https://doi.org/10.1007/s00421-012-2585-4 SN - 1439-6327 VL - 113 IS - 6 SP - 1605 EP - 1615 PB - Springer CY - Berlin ER - TY - JOUR A1 - Karamanidis, Kiros A1 - Albracht, Kirsten A1 - Braunstein, Bjoern A1 - Catala, Maria Moreno A1 - Goldmann, Jan-Peter A1 - Brüggemann, Gert-Peter T1 - Lower leg musculoskeletal geometry and sprint performance JF - Gait and Posture N2 - The purpose of this study was to investigate whether sprint performance is related to lower leg musculoskeletal geometry within a homogeneous group of highly trained 100-m sprinters. Using a cluster analysis, eighteen male sprinters were divided into two groups based on their personal best (fast: N = 11, 10.30 ± 0.07 s; slow: N = 7, 10.70 ± 0.08 s). Calf muscular fascicle arrangement and Achilles tendon moment arms (calculated by the gradient of tendon excursion versus ankle joint angle) were analyzed for each athlete using ultrasonography. Achilles tendon moment arm, foot and ankle skeletal geometry, fascicle arrangement as well as the ratio of fascicle length to Achilles tendon moment arm showed no significant (p > 0.05) correlation with sprint performance, nor were there any differences in the analyzed musculoskeletal parameters between the fast and slow sprinter group. Our findings provide evidence that differences in sprint ability in world-class athletes are not a result of differences in the geometrical design of the lower leg even when considering both skeletal and muscular components. Y1 - 2011 U6 - https://doi.org/10.1016/j.gaitpost.2011.03.009 SN - 0966-6362 VL - 34 IS - 1 SP - 138 EP - 141 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Arampatzis, Adamantios A1 - Peper, Andreas A1 - Bierbaum, Stefanie A1 - Albracht, Kirsten T1 - Plasticity of human Achilles tendon mechanical and morphological properties in response to cyclic strain JF - Journal of Biomechanics N2 - The purpose of the current study in combination with our previous published data (Arampatzis et al., 2007) was to examine the effects of a controlled modulation of strain magnitude and strain frequency applied to the Achilles tendon on the plasticity of tendon mechanical and morphological properties. Eleven male adults (23.9±2.2 yr) participated in the study. The participants exercised one leg at low magnitude tendon strain (2.97±0.47%), and the other leg at high tendon strain magnitude (4.72±1.08%) of similar frequency (0.5 Hz, 1 s loading, 1 s relaxation) and exercise volume (integral of the plantar flexion moment over time) for 14 weeks, 4 days per week, 5 sets per session. The exercise volume was similar to the intervention of our earlier study (0.17 Hz frequency; 3 s loading, 3 s relaxation) allowing a direct comparison of the results. Before and after the intervention ankle joint moment has been measured by a dynamometer, tendon–aponeurosis elongation by ultrasound and cross-sectional area of the Achilles tendon by magnet resonance images (MRI). We found a decrease in strain at a given tendon force, an increase in tendon–aponeurosis stiffness and tendon elastic modulus of the Achilles tendon only in the leg exercised at high strain magnitude. The cross-sectional area (CSA) of the Achilles tendon did not show any statistically significant (P>0.05) differences to the pre-exercise values in both legs. The results indicate a superior improvement in tendon properties (stiffness, elastic modulus and CSA) at the low frequency (0.17 Hz) compared to the high strain frequency (0.5 Hz) protocol. These findings provide evidence that the strain magnitude applied to the Achilles tendon should exceed the value, which occurs during habitual activities to trigger adaptational effects and that higher tendon strain duration per contraction leads to superior tendon adaptational responses. Y1 - 2010 U6 - https://doi.org/10.1016/j.jbiomech.2010.08.014 SN - 0021-9290 VL - 43 IS - 16 SP - 3073 EP - 3079 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Aggeloussis, Nickos A1 - Giannakou, Erasmia A1 - Albracht, Kirsten A1 - Arampatzis, Adamantios T1 - Reproducibility of fascicle length and pennation angle of gastrocnemius medialis in human gait in vivo JF - Gait and Posture N2 - The purpose of the current study was to examine the reproducibility of fascicle length and pennation angle of gastrocnemius medialis while human walking. To the best of our knowledge, this is the first study of the reproducibility of fascicle length and pennation angle of gastrocnemius medialis in vivo during human gait. Twelve males performed 10 gait trials on a treadmill, in 2 separate days. B-mode ultrasonography, with the ultrasound probe firmly adjusted in the transverse and frontal planes using a special cast, was used to measure the fascicle length and the pennation angle of the gastrocnemius medialis (GM). A Vicon 624 system with three cameras operating at 120 Hz was also used to record the ankle and knee joint angles. The results showed that measurements of fascicle length and pennation angle showed high reproducibility during the gait cycle, both within the same day and between different days. Moreover, the root mean square differences between the repeated waveforms of both variables were very small, compared with their ranges (fascicle length: RMS = ∼3 mm, range: 38–63 mm; pennation angle: RMS = ∼1.5°, range: 22–32°). However, their reproducibility was lower compared to the joint angles. It was found that representative data have to be derived by a wide number of gait trials (fascicle length ∼six trials, pennation angle more than 10 trials), to assure the reliability of the fascicle length and pennation angle in human gait. Y1 - 2010 U6 - https://doi.org/10.1016/j.gaitpost.2009.08.249 SN - 0966-6362 VL - 31 IS - 1 SP - 73 EP - 77 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Arampatzis, Adamantios A1 - Karamanidis, Kiros A1 - Mademli, Lida A1 - Albracht, Kirsten T1 - Plasticity of the human tendon to short and long-term mechanical loading JF - Exercise and Sport Sciences Reviews Y1 - 2009 U6 - https://doi.org/10.1097/JES.0b013e31819c2e1d SN - 1538-3008 VL - 37 IS - 2 SP - 66 EP - 72 ER - TY - JOUR A1 - Albracht, Kirsten A1 - Arampatzis, A. A1 - Baltzopoulos, V. T1 - Assessment of muscle volume and physiological cross-sectional area of the human triceps surae muscle in vivo JF - Journal of Biomechanics Y1 - 2008 U6 - https://doi.org/10.1016/j.jbiomech.2008.04.020 SN - 0021-9290 VL - 41 SP - 2211 EP - 2218 ER - TY - JOUR A1 - Miyamoto, Ko-Ichiro A1 - Sato, Takuya A1 - Abe, Minami A1 - Wagner, Torsten A1 - Schöning, Michael Josef A1 - Yoshinobu, Tatsuo T1 - Light-addressable potentiometric sensor as a sensing element in plug-based microfluidic devices JF - Micromachines N2 - A plug-based microfluidic system based on the principle of the light-addressable potentiometric sensor (LAPS) is proposed. The LAPS is a semiconductor-based chemical sensor, which has a free addressability of the measurement point on the sensing surface. By combining a microfluidic device and LAPS, ion sensing can be performed anywhere inside the microfluidic channel. In this study, the sample solution to be measured was introduced into the channel in a form of a plug with a volume in the range of microliters. Taking advantage of the light-addressability, the position of the plug could be monitored and pneumatically controlled. With the developed system, the pH value of a plug with a volume down to 400 nL could be measured. As an example of plug-based operation, two plugs were merged in the channel, and the pH change was detected by differential measurement. KW - light-addressable potentiometric sensor KW - plug-based microfluidic device KW - chemical sensor Y1 - 2016 U6 - https://doi.org/10.3390/mi7070111 SN - 2072-666X N1 - This article belongs to the Special Issue "Micro/Nano Devices for Chemical Analysis" VL - 7 IS - 7 SP - 111 PB - MDPI CY - Basel ER - TY - JOUR A1 - Welden, Rene A1 - Scheja, Sabrina A1 - Schöning, Michael Josef A1 - Wagner, Patrick A1 - Wagner, Torsten T1 - Electrochemical Evaluation of Light‐Addressable Electrodes Based on TiO2 for the Integration in Lab‐on‐Chip Systems JF - physica status solidi a : applications and materials sciences N2 - In lab-on-chip systems, electrodes are important for the manipulation (e.g., cell stimulation, electrolysis) within such systems. An alternative to commonly used electrode structures can be a light-addressable electrode. Here, due to the photoelectric effect, the conducting area can be adjusted by modification of the illumination area which enables a flexible control of the electrode. In this work, titanium dioxide based light-addressable electrodes are fabricated by a sol–gel technique and a spin-coating process, to deposit a thin film on a fluorine-doped tin oxide glass. To characterize the fabricated electrodes, the thickness, and morphological structure are measured by a profilometer and a scanning electron microscope. For the electrochemical behavior, the dark current and the photocurrent are determined for various film thicknesses. For the spatial resolution behavior, the dependency of the photocurrent while changing the area of the illuminated area is studied. Furthermore, the addressing of single fluid compartments in a three-chamber system, which is added to the electrode, is demonstrated. Y1 - 2018 U6 - https://doi.org/10.1002/pssa.201800150 SN - 1862-6319 VL - 215 IS - 15 SP - Article number 1800150 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Jildeh, Zaid B. A1 - Oberländer, Jan A1 - Kirchner, Patrick A1 - Wagner, Patrick H. A1 - Schöning, Michael Josef T1 - Thermocatalytic Behavior of Manganese (IV) Oxide as Nanoporous Material on the Dissociation of a Gas Mixture Containing Hydrogen Peroxide JF - Nanomaterials N2 - In this article, we present an overview on the thermocatalytic reaction of hydrogen peroxide (H₂O₂) gas on a manganese (IV) oxide (MnO₂) catalytic structure. The principle of operation and manufacturing techniques are introduced for a calorimetric H₂O₂ gas sensor based on porous MnO₂. Results from surface analyses by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) of the catalytic material provide indication of the H₂O₂ dissociation reaction schemes. The correlation between theory and the experiments is documented in numerical models of the catalytic reaction. The aim of the numerical models is to provide further information on the reaction kinetics and performance enhancement of the porous MnO₂ catalyst. Y1 - 2018 U6 - https://doi.org/10.3390/nano8040262 SN - 2079-4991 VL - 8 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Dikta, Gerhard T1 - Semi-parametric random censorship models JF - From Statistics to Mathematical Finance : Festschrift in Honour of Winfried Stute Y1 - 2017 SN - 978-3-319-50986-0 U6 - https://doi.org/10.1007/978-3-319-50986-0_3 SP - 43 EP - 56 PB - Springer CY - Berlin ER - TY - JOUR A1 - Pilas, Johanna A1 - Yazici, Y. A1 - Selmer, Thorsten A1 - Keusgen, M. A1 - Schöning, Michael Josef T1 - Application of a portable multi-analyte biosensor for organic acid determination in silage JF - Sensors N2 - Multi-analyte biosensors may offer the opportunity to perform cost-effective and rapid analysis with reduced sample volume, as compared to electrochemical biosensing of each analyte individually. This work describes the development of an enzyme-based biosensor system for multi-parametric determination of four different organic acids. The biosensor array comprises five working electrodes for simultaneous sensing of ethanol, formate, d-lactate, and l-lactate, and an integrated counter electrode. Storage stability of the biosensor was evaluated under different conditions (stored at +4 °C in buffer solution and dry at −21 °C, +4 °C, and room temperature) over a period of 140 days. After repeated and regular application, the individual sensing electrodes exhibited the best stability when stored at −21 °C. Furthermore, measurements in silage samples (maize and sugarcane silage) were conducted with the portable biosensor system. Comparison with a conventional photometric technique demonstrated successful employment for rapid monitoring of complex media. Y1 - 2018 U6 - https://doi.org/10.3390/s18051470 SN - 1424-8220 VL - 18 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Dantism, Shahriar A1 - Röhlen, Desiree A1 - Wagner, Torsten A1 - Wagner, Patrick A1 - Schöning, Michael Josef T1 - Optimization of Cell-Based Multi-Chamber LAPS Measurements Utilizing FPGA-Controlled Laser-Diode Modules JF - physica status solidi a : applications and materials sciences N2 - A light-addressable potentiometric sensor (LAPS) is a field-effect-based potentiometric device, which detects concentration changes of an analyte solution on the sensor surface in a spatially resolved way. It uses a light source to generate electron–hole pairs inside the semiconductor, which are separated in the depletion region due to an applied bias voltage across the sensor structure and hence, a surface-potential-dependent photocurrent can be read out. However, depending on the beam angle of the light source, scattering effects can occur, which influence the recorded signal in LAPS-based differential measurements. To solve this problem, a novel illumination unit based on a field programmable gate array (FPGA) consisting of 16 small-sized tunable infrared laser-diode modules (LDMs) is developed. Due to the improved focus of the LDMs with a beam angle of only 2 mrad, undesirable scattering effects are minimized. Escherichia coli (E. coli) K12 bacteria are used as a test microorganism to study the extracellular acidification on the sensor surface. Furthermore, a salt bridge chamber is built up and integrated with the LAPS system enabling multi-chamber differential measurements with a single Ag/AgCl reference electrode. Y1 - 2018 U6 - https://doi.org/10.1002/pssa.201800058 SN - 1862-6319 VL - 215 IS - 15 SP - Article number 1800058 PB - Wiley-VCH CY - Weinheim ER - TY - CHAP A1 - Schreiber, Marc A1 - Kraft, Bodo A1 - Zündorf, Albert T1 - NLP Lean Programming Framework: Developing NLP Applications More Effectively T2 - Proceedings of NAACL-HLT 2018: Demonstrations, New Orleans, Louisiana, June 2 - 4, 2018 N2 - This paper presents NLP Lean Programming framework (NLPf), a new framework for creating custom natural language processing (NLP) models and pipelines by utilizing common software development build systems. This approach allows developers to train and integrate domain-specific NLP pipelines into their applications seamlessly. Additionally, NLPf provides an annotation tool which improves the annotation process significantly by providing a well-designed GUI and sophisticated way of using input devices. Due to NLPf’s properties developers and domain experts are able to build domain-specific NLP applications more efficiently. NLPf is Opensource software and available at https:// gitlab.com/schrieveslaach/NLPf. Y1 - 2018 U6 - https://doi.org/10.18653/v1/N18-5001  ER - TY - JOUR A1 - Vahidpour, Farnoosh A1 - Oberländer, Jan A1 - Schöning, Michael Josef T1 - Flexible Calorimetric Gas Sensors for Detection of a Broad Concentration Range of Gaseous Hydrogen Peroxide: A Step Forward to Online Monitoring of Food-Package Sterilization Processes JF - Phys. Status Solidi A N2 - In this study, flexible calorimetric gas sensors are developed for specificdetection of gaseous hydrogen peroxide (H₂O₂) over a wide concentrationrange, which is used in sterilization processes for aseptic packaging industry.The flexibility of these sensors is an advantage for identifying the chemical components of the sterilant on the corners of the food boxes, so-called “coldspots”, as critical locations in aseptic packaging, which are of great importance. These sensors are fabricated on flexible polyimide films by means of thin-film technique. Thin layers of titanium and platinum have been deposited on polyimide to define the conductive structures of the sensors. To detect the high-temperature evaporated H₂O₂, a differential temperature set-up is proposed. The sensors are evaluated in a laboratory-scaled sterilizationsystem to simulate the sterilization process. The concentration range of the evaporated H₂O₂ from 0 to 7.7% v/v was defined and the sensors have successfully detected high as well as low H₂O₂ concentrations with a sensitivity of 5.04 °C/% v/v. The characterizations of the sensors confirm their precise fabrication, high sensitivity and the novelty of low H₂O₂ concentration detections for future inline monitoring of food-package sterilization. Y1 - 2018 U6 - https://doi.org/10.1002/pssa.201800044 VL - 215 IS - 15 PB - Wiley-VCH CY - Weinheim ER - TY - CHAP A1 - Schmidts, Oliver A1 - Kraft, Bodo A1 - Siebigteroth, Ines A1 - Zündorf, Albert T1 - Schema Matching with Frequent Changes on Semi-Structured Input Files: A Machine Learning Approach on Biological Product Data T2 - Proceedings of the 21st International Conference on Enterprise Information Systems - Volume 1: ICEIS Y1 - 2019 SN - 978-989-758-372-8 U6 - https://doi.org/10.5220/0007723602080215 SP - 208 EP - 215 ER - TY - JOUR A1 - Morais, Paulo V. A1 - Silva, Anielle C. A. A1 - Dantas, Noelio O. A1 - Schöning, Michael Josef A1 - Siqueira, José R., Jr. T1 - Hybrid Layer‐by‐Layer Film of Polyelectrolytes‐Embedded Catalytic CoFe2O4 Nanocrystals as Sensing Units in Capacitive Electrolyte‐Insulator‐Semiconductor Devices JF - physica status solidi a : applications and materials sciences Y1 - 2019 U6 - https://doi.org/10.1002/pssa.201900044 VL - 216 IS - 1900044 SP - 1 EP - 9 PB - Wiley CY - Weinheim ER - TY - JOUR A1 - Albanna, Walid A1 - Lüke, Jan Niklas A1 - Schubert, Gerrit Alexander A1 - Dibué-Adjei, Maxine A1 - Kotliar, Konstantin A1 - Hescheler, Jürgen A1 - Clusmann, Hans A1 - Steiger, Hans-Jakob A1 - Hänggi, Daniel A1 - Kamp, Marcel A. A1 - Schneider, Toni A1 - Neumaier, Felix T1 - Modulation of Ca v 2.3 channels by unconjugated bilirubin (UCB) – Candidate mechanism for UCB-induced neuromodulation and neurotoxicity JF - Molecular and Cellular Neuroscience Y1 - 2019 U6 - https://doi.org/10.1016/j.mcn.2019.03.003 SN - 1044-7431 VL - 96 IS - 4 SP - 35 EP - 46 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Breuer, Lars A1 - Pilas, Johanna A1 - Guthmann, Eric A1 - Schöning, Michael Josef A1 - Thoelen, Ronald A1 - Wagner, Torsten T1 - Towards light-addressable flow control: responsive hydrogels with incorporated graphene oxide as laser-driven actuator structures within microfluidic channels JF - Sensor and Actuators B: Chemical Y1 - 2019 U6 - https://doi.org/10.1016/j.snb.2019.02.086 SN - 0925-4005 VL - 288 SP - 579 EP - 585 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Cornelis, Peter A1 - Givanoudi, Stella A1 - Yongabi, Derick A1 - Iken, Heiko A1 - Duwé, Sam A1 - Deschaume, Olivier A1 - Robbens, Johan A1 - Dedecker, Peter A1 - Bartic, Carmen A1 - Wübbenhorst, Michael A1 - Schöning, Michael Josef A1 - Heyndrickx, Marc A1 - Wagner, Patrick T1 - Sensitive and specific detection of E. coli using biomimetic receptors in combination with a modified heat-transfer method JF - Biosensors and Bioelectronics Y1 - 2019 U6 - https://doi.org/10.1016/j.bios.2019.04.026 SN - 0956-5663 VL - 136 SP - 97 EP - 105 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Dadfar, Dryed Mohammadali A1 - Camozzi, Denise A1 - Darguzyte, Milita A1 - Roemhild, Karolin A1 - Varvarà, Paola A1 - Metselaar, Josbert A1 - Banala, Srinivas A1 - Straub, Marcel A1 - Güver, Nihan A1 - Engelmann, Ulrich M. A1 - Slabu, Ioana A1 - Buhl, Miriam A1 - Leusen, Jan van A1 - Kögerler, Paul A1 - Hermanns-Sachweh, Benita A1 - Schulz, Volkmar A1 - Kiessling, Fabian A1 - Lammers, Twan T1 - Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance JF - Journal of Nanobiotechnology N2 - Superparamagnetic iron oxide nanoparticles (SPION) are extensively used for magnetic resonance imaging (MRI) and magnetic particle imaging (MPI), as well as for magnetic fluid hyperthermia (MFH). We here describe a sequential centrifugation protocol to obtain SPION with well-defined sizes from a polydisperse SPION starting formulation, synthesized using the routinely employed co-precipitation technique. Transmission electron microscopy, dynamic light scattering and nanoparticle tracking analyses show that the SPION fractions obtained upon size-isolation are well-defined and almost monodisperse. MRI, MPI and MFH analyses demonstrate improved imaging and hyperthermia performance for size-isolated SPION as compared to the polydisperse starting mixture, as well as to commercial and clinically used iron oxide nanoparticle formulations, such as Resovist® and Sinerem®. The size-isolation protocol presented here may help to identify SPION with optimal properties for diagnostic, therapeutic and theranostic applications. Y1 - 2020 U6 - https://doi.org/10.1186/s12951-020-0580-1 SN - 1477-3155 VL - 18 IS - Article number 22 SP - 1 EP - 13 PB - Nature Portfolio ER - TY - JOUR A1 - Slabu, Ioana A1 - Roeth, Anjali A. A1 - Engelmann, Ulrich M. A1 - Wiekhorst, Frank A1 - Buhl, Eva M. A1 - Neumann, Ulf P. A1 - Schmitz-Rode, Thomas T1 - Modeling of magnetoliposome uptake in human pancreatic tumor cells in vitro JF - Nanotechnology Y1 - 2019 U6 - https://doi.org/10.1088/1361-6528/ab033e SN - 1361-6528 VL - 30 IS - 18 SP - 184004 ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Shasha, Carolyn A1 - Teeman, Eric A1 - Slabu, Iona A1 - Krishnan, Kannan M. T1 - Predicting size-dependent heating efficiency of magnetic nanoparticles from experiment and stochastic Néel-Brown Langevin simulation JF - Journal of Magnetism and Magnetic Materials Y1 - 2019 U6 - https://doi.org/10.1016/j.jmmm.2018.09.041 SN - 0304-8853 VL - 471 IS - 1 SP - 450 EP - 456 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Seifert, Julian A1 - Mues, Benedikt A1 - Roitsch, Stefan A1 - Ménager, Christine A1 - Schmidt, Annette M. A1 - Slabu, Ioana T1 - Heating efficiency of magnetic nanoparticles decreases with gradual immobilization in hydrogels JF - Journal of Magnetism and Magnetic Materials Y1 - 2019 U6 - https://doi.org/10.1016/j.jmmm.2018.09.113 SN - 0304-8853 VL - 471 IS - 1 SP - 486 EP - 494 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Roeth, Anjali A.J. A1 - Eberbeck, Dietmar A1 - Buhl, Eva Miriam A1 - Neumann, Ulf Peter A1 - Schmitz-Rode, Thomas A1 - Slabu, Ioana T1 - Combining Bulk Temperature and Nanoheating Enables Advanced Magnetic Fluid Hyperthermia Efficacy on Pancreatic Tumor Cells JF - Scientific Reports N2 - Many efforts are made worldwide to establish magnetic fluid hyperthermia (MFH) as a treatment for organ-confined tumors. However, translation to clinical application hardly succeeds as it still lacks of understanding the mechanisms determining MFH cytotoxic effects. Here, we investigate the intracellular MFH efficacy with respect to different parameters and assess the intracellular cytotoxic effects in detail. For this, MiaPaCa-2 human pancreatic tumor cells and L929 murine fibroblasts were loaded with iron-oxide magnetic nanoparticles (MNP) and exposed to MFH for either 30 min or 90 min. The resulting cytotoxic effects were assessed via clonogenic assay. Our results demonstrate that cell damage depends not only on the obvious parameters bulk temperature and duration of treatment, but most importantly on cell type and thermal energy deposited per cell during MFH treatment. Tumor cell death of 95% was achieved by depositing an intracellular total thermal energy with about 50% margin to damage of healthy cells. This is attributed to combined intracellular nanoheating and extracellular bulk heating. Tumor cell damage of up to 86% was observed for MFH treatment without perceptible bulk temperature rise. Effective heating decreased by up to 65% after MNP were internalized inside cells. Y1 - 2018 U6 - https://doi.org/10.1038/s41598-018-31553-9 SN - 2045-2322 VL - 8 IS - 1 SP - Article number 13210 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Buhl, Eva Miriam A1 - Draack, Sebastian A1 - Viereck, Thilo A1 - Frank, A1 - Schmitz-Rode, Thomas A1 - Slabu, Ioana T1 - Magnetic relaxation of agglomerated and immobilized iron oxide nanoparticles for hyperthermia and imaging applications JF - IEEE Magnetic Letters N2 - Magnetic nanoparticles (MNPs) are used as therapeutic and diagnostic agents for local delivery of heat and image contrast enhancement in diseased tissue. Besides magnetization, the most important parameter that determines their performance for these applications is their magnetic relaxation, which can be affected when MNPs immobilize and agglomerate inside tissues. In this letter, we investigate different MNP agglomeration states for their magnetic relaxation properties under excitation in alternating fields and relate this to their heating efficiency and imaging properties. With focus on magnetic fluid hyperthermia, two different trends in MNP heating efficiency are measured: an increase by up to 23% for agglomerated MNP in suspension and a decrease by up to 28% for mixed states of agglomerated and immobilized MNP, which indicates that immobilization is the dominant effect. The same comparatively moderate effects are obtained for the signal amplitude in magnetic particle spectroscopy. Y1 - 2018 U6 - https://doi.org/10.1109/LMAG.2018.2879034 SN - 1949-307X VL - 9 IS - Article number 8519617 PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Engelmann, Ulrich M. A1 - Buhl, Eva Miriam A1 - Baumann, Martin A1 - Schmitz-Rode, Thomas A1 - Slabu, Ioana T1 - Agglomeration of magnetic nanoparticles and its effects on magnetic hyperthermia JF - Current Directions in Biomedical Engineering Y1 - 2017 U6 - https://doi.org/10.1515/cdbme-2017-0096 SN - 2364-5504 VL - 3 IS - 2 SP - 457 EP - 460 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Chen, Chao A1 - Jost, Peter A1 - Volker, Hanno A1 - Kaminski, Marvin A1 - Wirtssohn, Matti R. A1 - Engelmann, Ulrich M. A1 - Krüger, K. A1 - Schlich, Franziska F. A1 - Schlockermann, Carl A1 - Lobo, Ricardo P.S.M. A1 - Wuttig, Matthias T1 - Dielectric properties of amorphous phase-change materials JF - Physical Review B Y1 - 2017 U6 - https://doi.org/10.1103/PhysRevB.95.094111 SN - 2469-9950 VL - 95 IS - 9 SP - Article number 094111 ER - TY - JOUR A1 - Dantism, Shahriar A1 - Röhlen, Desiree A1 - Wagner, Torsten A1 - Wagner, P. A1 - Schöning, Michael Josef T1 - A LAPS-based differential sensor for parallelized metabolism monitoring of various bacteria JF - Sensors N2 - Monitoring the cellular metabolism of bacteria in (bio)fermentation processes is crucial to control and steer them, and to prevent undesired disturbances linked to metabolically inactive microorganisms. In this context, cell-based biosensors can play an important role to improve the quality and increase the yield of such processes. This work describes the simultaneous analysis of the metabolic behavior of three different types of bacteria by means of a differential light-addressable potentiometric sensor (LAPS) set-up. The study includes Lactobacillus brevis, Corynebacterium glutamicum, and Escherichia coli, which are often applied in fermentation processes in bioreactors. Differential measurements were carried out to compensate undesirable influences such as sensor signal drift, and pH value variation during the measurements. Furthermore, calibration curves of the cellular metabolism were established as a function of the glucose concentration or cell number variation with all three model microorganisms. In this context, simultaneous (bio)sensing with the multi-organism LAPS-based set-up can open new possibilities for a cost-effective, rapid detection of the extracellular acidification of bacteria on a single sensor chip. It can be applied to evaluate the metabolic response of bacteria populations in a (bio)fermentation process, for instance, in the biogas fermentation process. Y1 - 2019 U6 - https://doi.org/10.3390/s19214692 SN - 1424-8220 VL - 19 IS - 21 PB - MDPI CY - Basel ER - TY - JOUR A1 - Karschuck, T. L. A1 - Filipov, Y. A1 - Bollella, P. A1 - Schöning, Michael Josef A1 - Katz, E. T1 - Not-XOR (NXOR) logic gate based on an enzyme-catalyzed reaction JF - International Journal of Unconventional Computing N2 - Enzyme-catalyzed reactions have been designed to mimic various Boolean logic gates in the general framework of unconventional biomolecular computing. While some of the logic gates, particularly OR, AND, are easy to realize with biocatalytic reactions and have been reported in numerous publications, some other, like NXOR, are very challenging and have not been realized yet with enzyme reactions. The paper reports on a novel approach to mimicking the NXOR logic gate using the bell-shaped enzyme activity dependent on pH values. Shifting pH from the optimum value to the acidic or basic values by using acid or base inputs (meaning 1,0 and 0,1 inputs) inhibits the enzyme reaction, while keeping the optimum pH (assuming 0,0 and 1,1 input combinations) preserves a high enzyme activity. The challenging part of the present approach is the selection of an enzyme with a well-demonstrated bell-shape activity dependence on the pH value. While many enzymes can satisfy this condition, we selected pyrroloquinoline quinone (PQQ)-dependent glucose dehydrogenase as this enzyme has the optimum pH center-located on the pH scale allowing the enzyme activity change by the acidic and basic pH shift from the optimum value corresponding to the highest activity. The present NXOR gate is added to the biomolecular “toolbox” as a new example of Boolean logic gates based on enzyme reactions. Y1 - 2019 SN - 1548-7199 VL - 14 IS - 3-4 SP - 235 EP - 242 PB - Old City Publishing CY - Philadelphia ER - TY - THES A1 - Engelmann, Ulrich M. T1 - Assessing magnetic fluid hyperthermia : magnetic relaxation simulation, modeling of nanoparticle uptake inside pancreatic tumor cells and in vitro efficacy Y1 - 2019 SN - 978-3-945954-58-4 N1 - Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2019 PB - Infinite Science Publishing CY - Lübeck ER - TY - JOUR A1 - Quittmann, Oliver J. A1 - Meskemper, Joshua A1 - Albracht, Kirsten A1 - Abel, Thomas A1 - Foitschik, Tina A1 - Strüder, Heiko K. T1 - Normalising surface EMG of ten upper-extremity muscles in handcycling: Manual resistance vs. sport-specific MVICs JF - Journal of Electromyography and Kinesiology N2 - Muscular activity in terms of surface electromyography (sEMG) is usually normalised to maximal voluntary isometric contractions (MVICs). This study aims to compare two different MVIC-modes in handcycling and examine the effect of moving average window-size. Twelve able-bodied male competitive triathletes performed ten MVICs against manual resistance and four sport-specific trials against fixed cranks. sEMG of ten muscles [M. trapezius (TD); M. pectoralis major (PM); M. deltoideus, Pars clavicularis (DA); M. deltoideus, Pars spinalis (DP); M. biceps brachii (BB); M. triceps brachii (TB); forearm flexors (FC); forearm extensors (EC); M. latissimus dorsi (LD) and M. rectus abdominis (RA)] was recorded and filtered using moving average window-sizes of 150, 200, 250 and 300 ms. Sport-specific MVICs were higher compared to manual resistance for TB, DA, DP and LD, whereas FC, TD, BB and RA demonstrated lower values. PM and EC demonstrated no significant difference between MVIC-modes. Moving average window-size had no effect on MVIC outcomes. MVIC-mode should be taken into account when normalised sEMG data are illustrated in handcycling. Sport-specific MVICs seem to be suitable for some muscles (TB, DA, DP and LD), but should be augmented by MVICs against manual/mechanical resistance for FC, TD, BB and RA. Y1 - 2020 U6 - https://doi.org/10.1016/j.jelekin.2020.102402 SN - 1050-6411 VL - 51 IS - Article 102402 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kopp, Alexander A1 - Schunck, Laura A1 - Gosau, Martin A1 - Smeets, Ralf A1 - Burg, Simon A1 - Fuest, Sandra A1 - Kröger, Nadja A1 - Zinser, Max A1 - Krohn, Sebastian A1 - Behbahani, Mehdi A1 - Köpf, Marius A1 - Lauts, Lisa A1 - Rutkowski, Rico T1 - Influence of the casting concentration on the mechanical and optical properties of Fa/CaCl2-derived silk fibroin membranes JF - International Journal of Molecular Sciences N2 - In this study, we describe the manufacturing and characterization of silk fibroin membranes derived from the silkworm Bombyx mori. To date, the dissolution process used in this study has only been researched to a limited extent, although it entails various potential advantages, such as reduced expenses and the absence of toxic chemicals in comparison to other conventional techniques. Therefore, the aim of this study was to determine the influence of different fibroin concentrations on the process output and resulting membrane properties. Casted membranes were thus characterized with regard to their mechanical, structural and optical assets via tensile testing, SEM, light microscopy and spectrophotometry. Cytotoxicity was evaluated using BrdU, XTT, and LDH assays, followed by live–dead staining. The formic acid (FA) dissolution method was proven to be suitable for the manufacturing of transparent and mechanically stable membranes. The fibroin concentration affects both thickness and transparency of the membranes. The membranes did not exhibit any signs of cytotoxicity. When compared to other current scientific and technical benchmarks, the manufactured membranes displayed promising potential for various biomedical applications. Further research is nevertheless necessary to improve reproducible manufacturing, including a more uniform thickness, less impurity and physiological pH within the membranes. Y1 - 2020 U6 - https://doi.org/10.3390/ijms21186704 SN - 1422-0067 N1 - Special issue: Optimization of Biomaterials for Reconstructive and Regenerative Medicine VL - 21 IS - 18 art. no. 6704 PB - MDPI CY - Basel ER - TY - CHAP A1 - Bozakov, Zdravko A1 - Sander, Volker T1 - OpenFlow: A Perspective for Building Versatile Networks T2 - Network-Embedded Management and Applications Y1 - 2013 SN - 978-1-4419-6769-5 U6 - https://doi.org/10.1007/978-1-4419-6769-5_11 SP - 217 EP - 245 PB - Springer CY - New York, NY ER - TY - BOOK A1 - Yoshinobu, Tatsuo A1 - Schöning, Michael Josef ED - Yoshinobu, Tatsuo ED - Schöning, Michael Josef T1 - Light-addressing and chemical imaging technologies for electrochemical sensing Y1 - 2020 SN - 978-3-03943-029-1 U6 - https://doi.org/10.3390/books978-3-03943-029-1 N1 - This book is a printed edition of the Special Issue Light-Addressing and Chemical Imaging Technologies for Electrochemical Sensing that was published in Sensors PB - MDPI CY - Basel ER - TY - JOUR A1 - Conzen, Catharina A1 - Albanna, Walid A1 - Weiss, Miriam A1 - Kürten, David A1 - Vilser, Walthard A1 - Kotliar, Konstantin A1 - Zäske, Charlotte A1 - Clusmann, Hans A1 - Schubert, Gerrit Alexander T1 - Vasoconstriction and Impairment of Neurovascular Coupling after Subarachnoid Hemorrhage: a Descriptive Analysis of Retinal Changes JF - Translational Stroke Research N2 - Impaired cerebral autoregulation and neurovascular coupling (NVC) contribute to delayed cerebral ischemia after subarachnoid hemorrhage (SAH). Retinal vessel analysis (RVA) allows non-invasive assessment of vessel dimension and NVC hereby demonstrating a predictive value in the context of various neurovascular diseases. Using RVA as a translational approach, we aimed to assess the retinal vessels in patients with SAH. RVA was performed prospectively in 24 patients with acute SAH (group A: day 5–14), in 11 patients 3 months after ictus (group B: day 90 ± 35), and in 35 age-matched healthy controls (group C). Data was acquired using a Retinal Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and NVC using flicker-light excitation. Diameter of retinal vessels—central retinal arteriolar and venular equivalent—was significantly reduced in the acute phase (p < 0.001) with gradual improvement in group B (p < 0.05). Arterial NVC of group A was significantly impaired with diminished dilatation (p < 0.001) and reduced area under the curve (p < 0.01) when compared to group C. Group B showed persistent prolonged latency of arterial dilation (p < 0.05). Venous NVC was significantly delayed after SAH compared to group C (A p < 0.001; B p < 0.05). To our knowledge, this is the first clinical study to document retinal vasoconstriction and impairment of NVC in patients with SAH. Using non-invasive RVA as a translational approach, characteristic patterns of compromise were detected for the arterial and venous compartment of the neurovascular unit in a time-dependent fashion. Recruitment will continue to facilitate a correlation analysis with clinical course and outcome. Y1 - 2018 U6 - https://doi.org/10.1007/s12975-017-0585-8 SN - 1868-601X IS - 9 SP - 284 EP - 293 PB - Springer Nature CY - Cham ER - TY - JOUR A1 - Hugenroth, Kristin A1 - Borchardt, Ralf A1 - Ritter, Philine A1 - Groß‑Hardt, Sascha A1 - Meyns, Bart A1 - Verbelen, Tom A1 - Steinseifer, Ulrich A1 - Kaufmann, Tim A. S. A1 - Engelmann, Ulrich M. T1 - Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input JF - Scientific Reports N2 - Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti2CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB. Y1 - 2021 U6 - https://doi.org/10.1038/s41598-021-96397-2 SN - 2045-2322 VL - 11 IS - Art. No. 16800 SP - 1 EP - 12 PB - Springer CY - Berlin ER - TY - JOUR A1 - Brockhaus, Moritz K. A1 - Behbahani, Mehdi A1 - Muris, Farina A1 - Jansen, Sebastian V. A1 - Schmitz- Rode, Thomas A1 - Steinseifer, Ulrich A1 - Clauser, Johanna C. T1 - In vitro thrombogenicity testing of pulsatile mechanical circulatory support systems: Design and proof-of-concept JF - Artificial Organs N2 - Thrombogenic complications are a main issue in mechanical circulatory support (MCS). There is no validated in vitro method available to quantitatively assess the thrombogenic performance of pulsatile MCS devices under realistic hemodynamic conditions. The aim of this study is to propose a method to evaluate the thrombogenic potential of new designs without the use of complex in-vivo trials. This study presents a novel in vitro method for reproducible thrombogenicity testing of pulsatile MCS systems using low molecular weight heparinized porcine blood. Blood parameters are continuously measured with full blood thromboelastometry (ROTEM; EXTEM, FIBTEM and a custom-made analysis HEPNATEM). Thrombus formation is optically observed after four hours of testing. The results of three experiments are presented each with two parallel loops. The area of thrombus formation inside the MCS device was reproducible. The implantation of a filter inside the loop catches embolizing thrombi without a measurable increase of platelet activation, allowing conclusions of the place of origin of thrombi inside the device. EXTEM and FIBTEM parameters such as clotting velocity (α) and maximum clot firmness (MCF) show a total decrease by around 6% with a characteristic kink after 180 minutes. HEPNATEM α and MCF rise within the first 180 minutes indicate a continuously increasing activation level of coagulation. After 180 minutes, the consumption of clotting factors prevails, resulting in a decrease of α and MCF. With the designed mock loop and the presented protocol we are able to identify thrombogenic hot spots inside a pulsatile pump and characterize their thrombogenic potential. Y1 - 2021 U6 - https://doi.org/10.1111/aor.14046 SN - 1525-1594 VL - 45 IS - 12 SP - 1513 EP - 1521 PB - Wiley CY - Weinheim ER - TY - CHAP A1 - Olderog, M. A1 - Mohr, P. A1 - Beging, Stefan A1 - Tsoumpas, C. A1 - Ziemons, Karl T1 - Simulation study on the role of tissue-scattered events in improving sensitivity for a compact time of flight compton positron emission tomograph T2 - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) N2 - In positron emission tomography improving time, energy and spatial detector resolutions and using Compton kinematics introduces the possibility to reconstruct a radioactivity distribution image from scatter coincidences, thereby enhancing image quality. The number of single scattered coincidences alone is in the same order of magnitude as true coincidences. In this work, a compact Compton camera module based on monolithic scintillation material is investigated as a detector ring module. The detector interactions are simulated with Monte Carlo package GATE. The scattering angle inside the tissue is derived from the energy of the scattered photon, which results in a set of possible scattering trajectories or broken line of response. The Compton kinematics collimation reduces the number of solutions. Additionally, the time of flight information helps localize the position of the annihilation. One of the questions of this investigation is related to how the energy, spatial and temporal resolutions help confine the possible annihilation volume. A comparison of currently technically feasible detector resolutions (under laboratory conditions) demonstrates the influence on this annihilation volume and shows that energy and coincidence time resolution have a significant impact. An enhancement of the latter from 400 ps to 100 ps leads to a smaller annihilation volume of around 50%, while a change of the energy resolution in the absorber layer from 12% to 4.5% results in a reduction of 60%. The inclusion of single tissue-scattered data has the potential to increase the sensitivity of a scanner by a factor of 2 to 3 times. The concept can be further optimized and extended for multiple scatter coincidences and subsequently validated by a reconstruction algorithm. Y1 - 2021 SN - 978-1-7281-7693-2 U6 - https://doi.org/10.1109/NSS/MIC42677.2020.9507901 N1 - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 31 Oct.-7 Nov. 2020, Boston, MA, USA PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Arampatzis, Adamantios A1 - Karamanidis, Kiros A1 - Albracht, Kirsten T1 - Adaptational responses of the human Achilles tendon by modulation of the applied cyclic strain magnitude JF - Journal of Experimental Biology Y1 - 2007 U6 - https://doi.org/10.1242/jeb.003814 SN - 0022-0949 VL - 210 IS - 15 SP - 2743 EP - 2753 ER - TY - JOUR A1 - Albracht, Kirsten A1 - Arampatzis, Adamantios T1 - Influence of the mechanical properties of the muscle-tendon unit on force generation in runners with different running economy JF - Biological Cybernetics Y1 - 2006 U6 - https://doi.org/10.1007/s00422-006-0070-z SN - 1432-0770 VL - 95 IS - 1 SP - 87 EP - 96 ER - TY - JOUR A1 - Sousa, Marcos A. M. A1 - Siqueira, Jose R. Jr. A1 - Vercik, Andres A1 - Schöning, Michael Josef A1 - Oliveira, Osvaldo N. Jr. T1 - Determining the optimized layer-by-layer film architecture with dendrimer/carbon nanotubes for field-effect sensors JF - IEEE Sensors Journal N2 - The capacitive electrolyte–insulator–semiconductor (EIS) structure is a typical device based on a field-effect sensor platform. With a simple silicon-based structure, EIS have been useful for several sensing applications, especially with incorporation of nanostructured films to modulate the ionic transport and the flat-band potential. In this paper, we report on ion transport and changes in flat-band potential in EIS sensors made with layer-by-layer films containing poly(amidoamine) (PAMAM) dendrimer and single-walled carbon nanotubes (SWNTs) adsorbed on p-Si/SiO 2 /Ta 2 O 5 chips with an Al ohmic contact. The impedance spectra were fitted using an equivalent circuit model, from which we could determine parameters such as the double-layer capacitance. This capacitance decreased with the number of bilayers owing to space charge accumulated at the electrolyte–insulator interface, up to three PAMAM/SWNTs bilayers, after which it stabilized. The charge-transfer resistance was also minimum for three bilayers, thus indicating that this is the ideal architecture for an optimized EIS performance. The understanding of the influence of nanostructures and the fine control of operation parameters pave the way for optimizing the design and performance of new EIS sensors. Y1 - 2017 U6 - https://doi.org/10.1109/JSEN.2017.2653238 SN - 1558-1748 VL - 17 IS - 6 SP - 1735 EP - 1740 PB - IEEE CY - New York ER - TY - JOUR A1 - Arreola, Julio A1 - Oberländer, Jan A1 - Mätzkow, M. A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Surface functionalization for spore-based biosensors with organosilanes JF - Electrochimica Acta N2 - In the present work, surface functionalization of different sensor materials was studied. Organosilanes are well known to serve as coupling agent for biomolecules or cells on inorganic materials. 3-aminopropyltriethoxysilane (APTES) was used to attach microbiological spores time to an interdigitated sensor surface. The functionality and physical properties of APTES were studied on isolated sensor materials, namely silicon dioxide (SiO2) and platinum (Pt) as well as the combined material on sensor level. A predominant immobilization of spores could be demonstrated on SiO2 surfaces. Additionally, the impedance signal of APTES-functionalized biosensor chips has been investigated. Y1 - 2017 U6 - https://doi.org/10.1016/j.electacta.2017.04.157 SN - 0013-4686 VL - 241 SP - 237 EP - 243 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Oberländer, Jan A1 - Mayer, Marlena A1 - Greeff, Anton A1 - Keusgen, Michael A1 - Schöning, Michael Josef T1 - Spore-based biosensor to monitor the microbicidal efficacy of gaseous hydrogen peroxide sterilization processes JF - Biosensors and Bioelectronics N2 - In this work, a spore-based biosensor is evaluated to monitor the microbicidal efficacy of sterilization processes applying gaseous hydrogen peroxide (H2O2). The sensor is based on interdigitated electrode structures (IDEs) that have been fabricated by means of thin-film technologies. Impedimetric measurements are applied to study the effect of sterilization process on spores of Bacillus atrophaeus. This resilient microorganism is commonly used in industry to proof the sterilization efficiency. The sensor measurements are accompanied by conventional microbiological challenge tests, as well as morphological characterizations with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The sensor measurements are correlated with the microbiological test routines. In both methods, namely the sensor-based and microbiological one, a tailing effect has been observed. The results are evaluated and discussed in a three-dimensional calibration plot demonstrating the sensor's suitability to enable a rapid process decision in terms of a successfully performed sterilization. Y1 - 2018 U6 - https://doi.org/10.1016/j.bios.2017.12.045 SN - 0956-5663 VL - 104 SP - 87 EP - 94 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Schmidts, Oliver A1 - Boltes, Maik A1 - Kraft, Bodo A1 - Schreiber, Marc T1 - Multi-pedestrian tracking by moving Bluetooth-LE beacons and stationary receivers T2 - 2017 International Conference on Indoor Positioning and Indoor Navigation (IPIN), 18-21 September 2017, Sapporo, Japan Y1 - 2017 N1 - International Conference on Indoor Positioning and Indoor Navigation <8, 2017, Sapporo, Japan> SP - 1 EP - 4 ER - TY - JOUR A1 - Laura, C.O. A1 - Drechsler, Klaus A1 - Erdt, M. A1 - Wesarg, S. A1 - Bale, R. T1 - Intervention assessment tool for primary tumors in the liver JF - Current Directions in Biomedical Engineering N2 - After a liver tumor intervention the medical doctor has to compare both pre and postoperative CT acquisitions to ensure that all carcinogenic cells are destroyed. A correct assessment of the intervention is of vital importance, since it will reduce the probability of tumor recurrence. Some methods have been proposed to support the medical doctors during the assessment process, however, all of them focus on secondary tumors. In this paper a tool is presented that enables the outcome validation for both primary and secondary tumors. Therefore, a multiphase registration (preoperative arterial and portal phases) followed by a registration between the pre and postoperative CT images is carried out. The first registration is in charge of the primary tumors that are only visible in the arterial phase. The secondary tumors will be incorporated in the second registration step. Finally, the part of the tumor that was not covered by the necrosis is quantified and visualized. The method has been tested in 9 patients, with an average registration error of 1.41 mm. Y1 - 2018 U6 - https://doi.org/10.1515/cdbme-2018-0081 SN - 2364-5504 VL - 4 IS - 1 SP - 337 EP - 340 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Heinke, Lars N. A1 - Knicker, Axel J. A1 - Albracht, Kirsten T1 - Evaluation of passively induced shoulder stretch reflex using an isokinetic dynamometer in male overhead athletes JF - Isokinetics and Exercise Science N2 - BACKGROUND: Muscle stretch reflexes are widely considered to beneficially influence joint stability and power generation in the lower limbs. While in the upper limbs and especially in the muscles surrounding the shoulder joint such evidence is lacking. OBJECTIVE: To quantify the electromyographical response in the muscles crossing the shoulder of specifically trained overhead athletes to an anterior perturbation force. METHODS: Twenty healthy male participants performed six sets of different external shoulder rotation stretches on an isokinetic dynamometer over a range of amplitudes and muscle pre-activation moment levels. All stretches were applied with a dynamometer acceleration of 10,000∘/s2 and a velocity of 150∘/s. Electromyographical response was measured via sEMG. RESULTS: Consistent reflexes were not observed in all experimental conditions. The reflex latencies revealed a significant muscle main effect (F (2,228) = 99.31, p< 0.001; η2= 0.466; f= 0.934) and a pre-activation main effect (F (1,228) = 142.21, p< 0.001; η2= 0.384; f= 1.418). The stretch reflex amplitude yielded a significant pre-activation main effect (F (1,222) = 470.373, p< 0.001; η2= 0.679; f= 1.454). CONCLUSION: Short latency muscle reflexes showed a tendency to an anterior to posterior muscle recruitment whereby the main internal rotator muscles of the shoulder revealed the most consistent results. Y1 - 2018 U6 - https://doi.org/10.3233/IES-184111 SN - 1878-5913 VL - 26 IS - 4 SP - 265 EP - 274 PB - IOS Press CY - Amsterdam ER -