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Item type:Publication, Access status: without files , Stresses and deformations of an osteosynthesis plate in a lateral tibia plateau fracture(2022-01-01); ; ; ; This study has the aim to investigate the strain and stress in an anterolateral locking plate applied for the fixation of a lateral split fracture. To simulate a complex fracture situation, three segments were separated. With a FEM analysis, representative places for strain and stress measurement were determined. A locked osteosynthesis plate was instrumented with strain gauges and tested on a fractured and a non-fractured Saw Bone model. To simulate different loading situations, four different points of force application, from the center of the condyles to a 15 mm posterior position, were used with a medial-lateral load distribution of 60:40. The simulations as well as the biomechanical tests demonstrated that two deformations dominate the load on the plate: a bending into posterior direction and a bulging of the plate head. Shifting the point of application to the posterior direction resulted in increasing maximum stress, from 1.16 to 6.32 MPa (FEM analysis) and from 3.04 to 7.00 MPa (biomechanical study), respectively. Furthermore, the comparison of the non-fractured and fractured models showed an increase in maximum stress by the factor 2.06-2.2 (biomechanical investigation) and 1.5-3.3 (FEM analysis), respectively.Publicationtype: Journal ArticleScopus© Citations 2 46 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Modular 3D printable orthodontic measuring apparatus for force and torque measurements of thermoplastic/removable appliancesThe magnitude of forces and moments applied on teeth during orthodontic treatment is crucial to achieve the desired tooth movement. The aim of this study is to introduce a modular 3D printable orthodontic measurement apparatus (M3DOMA), which can be used for measurements of forces and moments acting on teeth during treatment with aligners. The measurement device was characterized regarding signal to noise ratio (SNR) of the sensors, repeatability of measurements, influence of thermoforming, as well as reliability. Forces and moments were evaluated for an activation range of 0.1-0.4 mm, comparing them among different activation patterns with two aligner thicknesses. The sensors exhibited a SNR from 13-33 dB. Repeatability with repeated measurements showed standard deviations ≤0.015 N and 0.769 Nmm. The influence of thermoforming represented by standard deviation of forces ranges from 0.019-0.147 N. The device showed a range of intra class correlation (ICC) for repeated measurements for all sensors from 0.932 to 0.999. Hence the reliability of the device has been proven to be excellent.Publicationtype: Journal Article97 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Development of a fully implantable EMG measurement system : status report on the MyoPlant project(De Gruyter, 2014); ; ; ; MyoPlant is a publicly funded research project that developed a fully implantable EMG measurement system. The system consists of a central implant, and single silicone electrodes that are placed on the muscles of choice. Electrodes are connected by means of subcutaneous cables. While electrodes were tested in rats, the complete system was tested in sheep and rhesus macaques. Electrodes showed good handling during surgery and were well tolerated by all animals without adverse reactions. No electrode defects were observed during the runtime of the project. Data from the animal trials showed that electrodes are well encapsulated after approximately eight weeks. The custom designed chip in the central implant performed as intended. Data transmission and inductive energy supply worked as designed. The latter was susceptible to coil misalignment. Electromyographic signals recorded with the system showed very good separation between electrodes, no cross-talk and no 50Hz noise. Amplitudes were consistent between sessions. Overall, we were able to demonstrate the technical feasibility of a fully implantable EMG measurement system. The recorded signals seem well suited to control modern myoelectric arm prostheses with multiple degrees of freedom in the future.Publicationtype: Journal Article58 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Wireless power transmission for powering medical implants situated in an abdominal aortic aneurysmThis paper will describe a wireless power transmission system which has been used during in vivo testing to power a blood pressure sensing implant [1] located inside the abdominal aorta of a 100 kg swine. Wireless power transmission is accomplished using an external power sender which is magnetically coupled to an RF energy harvester block which has been integrated into the medical implant's system package. The power sender is a class E amplifier which drives a wire loop antenna at 4 MHz, and the power receiver uses a ferro-magnetic core in an LC resonant circuit coupled to a Schottky diode charge pump rectifier followed by a DC voltage regulator. © 2012 by Walter de Gruyter. Berlin. Boston.Publicationtype: Journal Article129 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , CMOS based capacitive biosensor with integrated tethered bilayer lipid membrane for real-time measurements(De Gruyter, 2012-08-30); ; ; ; Conventional methods to investigate ionophore concentration require complex laboratory equipment. One approach to reduce the size of devices for the biosensor application is the implementation of the sensor circuits on CMOS microchips. Thus a new approach for the detection of changes in the ionophore concentration in tethered Bilayer Lipid Membranes (tBLMs) implemented in CMOS has been developed. In case of ion transport across the membrane by ionophores the ion concentration in the spacer region of the membrane is increased. This causes a permittivity increase and therefore a change of the capacitance of the spacer region which can be measured. The advantages of the capacitive biosensor principle are label-free measurements with short measurement times in the millisecond range. The test of the sensor chip with a circuit that mimics the membrane shows very good agreement between simulation and measurement. In addition, a Valinomycin concentration of 100 nM has been detected. An estimation of the detection limit gives a value of about 10 pM. © 2012 by Walter de Gruyter Berlin Boston.Publicationtype: Journal Article133 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Microelectromechanical implants : encapsulation concepts and test proceduresPublicationtype: Journal Article107 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 5 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Pyramid multiscale products for noise reduction of medical X-Ray image sequencesPublicationtype: Conference Paper44 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Motion and noise detection for spatio-temporal filtering of medical X-ray image sequences(Schiele & Schön, 2005); ; ; ; Publicationtype: Journal Article30 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , The pulsed water jet for selective removal of bone cement during revision arthroplasty(De Gruyter, 2003); ; ; 8