Refine
Year of publication
- 2021 (56) (remove)
Institute
- Fachbereich Medizintechnik und Technomathematik (56) (remove)
Document Type
- Article (39)
- Conference Proceeding (7)
- Book (2)
- Part of a Book (2)
- Doctoral Thesis (2)
- Report (2)
- Other (1)
- Preprint (1)
Keywords
- constructive alignment (2)
- examination (2)
- long-term retention (2)
- multimodal (2)
- practical learning (2)
- AlterG (1)
- Bacillus sp (1)
- Biosolubilization (1)
- Bone quality and biomechanics (1)
- Bootstrap (1)
- Boundary integral equations (1)
- Capacitive field-effect sensor (1)
- CellDrum (1)
- Coefficient of ocular rigidity (1)
- Corneo-scleral shell (1)
- Differential tonometry (1)
- EEG (1)
- Empirical process (1)
- Environmental impact (1)
- Eyeball (1)
- Frequency mixing magnetic detection (1)
- Functional Delta Method (1)
- Glaucoma (1)
- Hadamard differentiability (1)
- Helmholtz equation (1)
- Impedance Spectroscopy (1)
- Interior Neumann eigenvalues (1)
- LPS (1)
- Label-free detection (1)
- Langevin theory (1)
- Machine learning (1)
- Magnetic nanoparticles (1)
- Micromagnetic simulation (1)
- Muscle Fascicle (1)
- Muscle Force (1)
- Natural language processing (1)
- Neuromuskuläres System (1)
- Nonequilibrium dynamics (1)
- Numerics (1)
- Ocular blood flow (1)
- Paired sample (1)
- Plant virus (1)
- Potential theory (1)
- Pressure-volume relationship (1)
- Process model (1)
- RVA (1)
- Rehabilitationsmedizin (1)
- Rehabilitatives Training (1)
- Robotik (1)
- Septic cardiomyopathy (1)
- Simulation (1)
- Skeletal muscle (1)
- Sleep EEG (1)
- Small Aral Sea (1)
- Stiffness (1)
- TMV adsorption (1)
- Ta₂O₅ gate (1)
- Tendon Rupture (1)
- Tendons (1)
- Tobacco mosaic virus (TMV) (1)
- Trainingsgerät (1)
- Ultrasound (1)
- Vascular response (1)
- Visual field asymmetry (1)
- Zeta potential (1)
- acetoin (1)
- acetoin reductase (1)
- actin cytoskeleton (1)
- alcoholic beverages (1)
- bioburdens (1)
- biopotential electrodes (1)
- biosensors (1)
- capacitive electrolyte–insulator–semiconductor sensors (1)
- capacitive field-effect sensor (1)
- capacitive field-effect sensors (1)
- cardiomyocyte biomechanics (1)
- drop jump (1)
- ecological structure (1)
- enzymatic biosensor (1)
- gait (1)
- graphene oxide (1)
- humic acid (1)
- hyper-gravity (1)
- hypo-gravity (1)
- intraclass correlation coefficient (1)
- layer-by-layer technique (1)
- lignite (1)
- locomotion (1)
- metagenomics (1)
- microbial diversity (1)
- muscle fascicle behavior (1)
- muscle mechanics (1)
- nanomaterials (1)
- parabolic flight (1)
- penicillin (1)
- penicillinase (1)
- photoelectrochemistry (1)
- plant virus detection (1)
- polyaniline (1)
- rehabilitation (1)
- running (1)
- sarcomere operating length (1)
- sensors (1)
- series elastic element behavior (1)
- shotgun sequencing (1)
- shoulder (1)
- sprint start (1)
- standard error of measurement (1)
- sterility tests (1)
- sterilization efficacy (1)
- sterilization methods (1)
- stretch reflex (1)
- test-retest reliability (1)
- titanium dioxide photoanode (1)
- tobacco mosaic virus (TMV) (1)
- ultrasonography (1)
- ultrasound imaging (1)
- unloading (1)
- validation methods (1)
- walking (1)
In the context of the Solvency II directive, the operation of an internal risk model is a possible way for risk assessment and for the determination of the solvency capital requirement of an insurance company in the European Union. A Monte Carlo procedure is customary to generate a model output. To be compliant with the directive, validation of the internal risk model is conducted on the basis of the model output. For this purpose, we suggest a new test for checking whether there is a significant change in the modeled solvency capital requirement. Asymptotic properties of the test statistic are investigated and a bootstrap approximation is justified. A simulation study investigates the performance of the test in the finite sample case and confirms the theoretical results. The internal risk model and the application of the test is illustrated in a simplified example. The method has more general usage for inference of a broad class of law-invariant and coherent risk measures on the basis of a paired sample.
Test-retest reliability of the internal shoulder rotator muscles' stretch reflex in healthy men
(2021)
Until now the reproducibility of the short latency stretch reflex of the internal rotator muscles of the glenohumeral joint has not been identified. Twenty-three healthy male participants performed three sets of external shoulder rotation stretches with various pre-activation levels on two different dates of measurement to assess test-retest reliability. All stretches were applied with a dynamometer acceleration of 104°/s2 and a velocity of 150°/s. Electromyographical response was measured via surface EMG. Reflex latencies showed a pre-activation effect (ƞ2 = 0,355). ICC ranged from 0,735 to 0,909 indicating an overall “good” relative reliability. SRD 95% lay between ±7,0 to ±12,3 ms.. The reflex gain showed overall poor test-retest reproducibility. The chosen methodological approach presented a suitable test protocol for shoulder muscles stretch reflex latency evaluation. A proof-of-concept study to validate the presented methodical approach in shoulder involvement including subjects with clinically relevant conditions is recommended.
Stretch-shortening type actions are characterized by lengthening of the pre-activated muscle-tendon unit (MTU) in the eccentric phase immediately followed by muscle shortening. Under 1 g, pre-activity before and muscle activity after ground contact, scale muscle stiffness, which is crucial for the recoil properties of the MTU in the subsequent push-off. This study aimed to examine the neuro-mechanical coupling of the stretch-shortening cycle in response to gravity levels ranging from 0.1 to 2 g. During parabolic flights, 17 subjects performed drop jumps while electromyography (EMG) of the lower limb muscles was combined with ultrasound images of the gastrocnemius medialis, 2D kinematics and kinetics to depict changes in energy management and performance. Neuro-mechanical coupling in 1 g was characterized by high magnitudes of pre-activity and eccentric muscle activity allowing an isometric muscle behavior during ground contact. EMG during pre-activity and the concentric phase systematically increased from 0.1 to 1 g. Below 1 g the EMG in the eccentric phase was diminished, leading to muscle lengthening and reduced MTU stretches. Kinetic energy at take-off and performance were decreased compared to 1 g. Above 1 g, reduced EMG in the eccentric phase was accompanied by large MTU and muscle stretch, increased joint flexion amplitudes, energy loss and reduced performance. The energy outcome function established by linear mixed model reveals that the central nervous system regulates the extensor muscles phase- and load-specifically. In conclusion, neuro-mechanical coupling appears to be optimized in 1 g. Below 1 g, the energy outcome is compromised by reduced muscle stiffness. Above 1 g, loading progressively induces muscle lengthening, thus facilitating energy dissipation.
The hot spots conjecture is only known to be true for special geometries. This paper shows numerically that the hot spots conjecture can fail to be true for easy to construct bounded domains with one hole. The underlying eigenvalue problem for the Laplace equation with Neumann boundary condition is solved with boundary integral equations yielding a non-linear eigenvalue problem. Its discretization via the boundary element collocation method in combination with the algorithm by Beyn yields highly accurate results both for the first non-zero eigenvalue and its corresponding eigenfunction which is due to superconvergence. Additionally, it can be shown numerically that the ratio between the maximal/minimal value inside the domain and its maximal/minimal value on the boundary can be larger than 1 + 10− 3. Finally, numerical examples for easy to construct domains with up to five holes are provided which fail the hot spots conjecture as well.