Lebenswissenschaften und Ethik
Refine
Year of publication
Document Type
- Article (106)
- conference proceeding (article) (86)
- conference talk (37)
- conference proceeding (presentation, abstract) (30)
- Part of a Book (4)
- Doctoral Thesis (3)
- Moving Images (2)
- Other (2)
- conference proceeding (volume) (1)
- Edited collection (1)
Is part of the Bibliography
- no (275)
Keywords
- Biomechanik (13)
- Biomechanics (10)
- Simulation (10)
- Hüftgelenkprothese (9)
- Biomechanische Analyse (7)
- Stent (6)
- Bewegungsapparat (4)
- Finite element analysis (4)
- Spongiosa (4)
- biomechanics (4)
- AnyBody (3)
- Computerunterstütztes Verfahren (3)
- Deformation (3)
- ECMO (3)
- Finite-Elemente-Methode (3)
- Gait analysis (3)
- Inverse dynamics (3)
- Lumbar spine (3)
- Musculoskeletal simulation (3)
- Operationstechnik (3)
- Schultergelenk (3)
- THA (3)
- musculoskeletal simulation (3)
- Adhesives (2)
- Aerosols (2)
- Alter (2)
- Anisotropie (2)
- AnyBody Modeling System (2)
- Ballondilatation (2)
- Belastung (2)
- Biomaterial (2)
- Blood Viscosity (2)
- Breast augmentation (2)
- CFD (2)
- Catheters (2)
- Combined anteversion (2)
- Computertomografie (2)
- Coronary stenting (2)
- Flow visualisation (2)
- Implantation (2)
- Knochen (2)
- Knochenbruch (2)
- Lendenwirbelsäule (2)
- Mechanische Belastung (2)
- Membrane Oxygenator (2)
- Musculoskeletal Modeling (2)
- Nasal airflow (2)
- Numerische Strömungssimulation (2)
- Stiffness (2)
- Stress (2)
- Test (2)
- Tissue Engineering (2)
- Tomographic PIV (2)
- computational fluid dynamics (2)
- stem cells (2)
- total hip replacement (2)
- 3D measurement (1)
- 3D scan (1)
- 3D volumetry (1)
- 3D-Druck (1)
- ANEURYSMS (1)
- ANTERIOR CINGULATE CORTEX (1)
- ANTERIOR CRUCIATE LIGAMENT (1)
- APOPTOSIS (1)
- ARTERIES (1)
- ASCORBIC-ACID (1)
- ASIS (1)
- AUGMENTATION (1)
- Abduction tasks (1)
- Accoucheur (1)
- Acetabulum/physiology (1)
- Adaptive clinical trial (1)
- Aerodynamics (1)
- Aerosole (1)
- Altenpflege (1)
- Aluminum Silicates (1)
- Animals (1)
- Anisotropy (1)
- Antibiotika (1)
- Antioxidant (1)
- Arbeitsbedingungen (1)
- Arbeitshilfe (1)
- Assistenzsystem (1)
- Autologous bone graft (1)
- BIOREACTOR (1)
- BLOOD FLOW (1)
- BLOOD-VESSELS (1)
- BYPASS GRAFTS (1)
- Beckenbruch (1)
- Beckenkammknochen (1)
- Beweglichkeit (1)
- Bewegung (1)
- Bewegungsanalyse (1)
- Bewegungsanalyse <Technik> (1)
- Bildbasierte Verfahren (1)
- Bildgebendes Verfahren (1)
- Bioactivity (1)
- Biological models (1)
- Biologische Modelle (1)
- Biomechanical Phenomena (1)
- Biomechanical investigation (1)
- Blutdruck (1)
- Blutgefäß (1)
- Body Weight (1)
- Bond strength (1)
- Bone harvesting (1)
- Bone imaging (1)
- Bone substitute materials (1)
- Bovine cartilage (1)
- Breast cancer (1)
- Breast implant (1)
- Breathing cycle (1)
- Brusterhaltende Therapie (1)
- Brustkorb (1)
- Brustwirbelsäule (1)
- CANCER (1)
- CELT (1)
- CEUS (1)
- COMPLEX (1)
- CONNECTIVITY (1)
- CONSTRUCTS (1)
- CONTRAST AGENT (1)
- COORDINATE SYSTEM (1)
- COVID-19 (1)
- CULTURES (1)
- Cancellous bone (1)
- Cancer-cells (1)
- Cardiovascular stents (1)
- Cartilage samples (1)
- Catheter (1)
- Ceramics (1)
- Characterisation testing (1)
- Classification (1)
- Coherent motion detection (1)
- Communication engineering education (1)
- Computational Fluid Dynamics Simulation (1)
- Computer-assisted surgery (1)
- Computersimulation (1)
- Computertomographie (1)
- Conventional surgery (1)
- Convolutional neural networks (1)
- Coronary (1)
- Coronary artery (1)
- Corrosion rate (1)
- Corrosion test (1)
- Covid-19 (1)
- Crimping (1)
- Cup medialisation (1)
- DEFICIENCY (1)
- Damage (1)
- Damage mechanism (1)
- Deep Learning (1)
- Deep learning fluid mechanics (1)
- Deformation behaviour (1)
- Dental Materials (1)
- Dental alloys (1)
- Dental membrane (1)
- Dentin (1)
- Depression (1)
- Deutschland (1)
- Distraktion (1)
- Dragonfly (1)
- Dragonfly wing (1)
- Dreidimensionale Bildverarbeitung (1)
- EARLY OSTEOARTHRITIS (1)
- ECMO SYSTEMS (1)
- EMG (1)
- Early recovery (1)
- Einflussgröße (1)
- Elasticity (1)
- Electromyography (1)
- Elektromyographie (1)
- Elite athletes (1)
- Ellenbogenstabilität (1)
- Empfindlichkeit (1)
- Endotracheal Intubation (1)
- Endotracheal Tube (1)
- Equipment Failure Analysis/statistics & numerical data (1)
- Ergonomics (1)
- Ermüdung (1)
- Ermüdungsbruch (1)
- Euler-Bernoulli-Beam-Theory (1)
- Ex vivo porcine stent model (1)
- Extracorporeal Membrane Oxygenation/instrumentation (1)
- FEA (1)
- FORCE (1)
- FRONTAL-CORTEX (1)
- Fat graft (1)
- Fatigue (1)
- Fatigue fracture (1)
- Feedback (1)
- Femur first (1)
- Finite element (1)
- Finite element analysis (FEA) (1)
- Flow (1)
- Fluid Mechanics (1)
- Football (1)
- Functional MRI (1)
- Funktionelle Anatomie (1)
- GAIT (1)
- GULO (1)
- Gait (1)
- Ganganalyse (1)
- Gefäßverletzung (1)
- Gehen (1)
- Geometrical imperfections (1)
- Geometrie (1)
- Germany (1)
- Glenohumeral joint reaction force (1)
- Glenohumeral stability (1)
- Gliding Flight (1)
- Ground Reaction Force Prediction (1)
- HYDROGELS (1)
- Haltungsfehler (1)
- Haut (1)
- Head trauma (1)
- Heat treatment (1)
- Hemodynamics (1)
- Hip Prosthesis (1)
- Hochschulschrift (1)
- Humans (1)
- Hyaluronsäure (1)
- Hämodynamik (1)
- Hüftgelenk (1)
- Hüftgelenkpfanne (1)
- IMMEDIATE BREAST RECONSTRUCTION (1)
- IMU (1)
- IN-VITRO (1)
- INFLAMMATION (1)
- INJURY (1)
- INSTABILITY (1)
- Iliac crest (1)
- Indentation test (1)
- Indian ink (1)
- Inertial Measurement Units (1)
- Injury score (1)
- Internal fixator (1)
- Ion release (1)
- Joint Reaction Forces (1)
- Kardiovaskuläres System (1)
- Kennzeichnung (1)
- Kicks (1)
- Kniegelenk (1)
- Kniegelenkband (1)
- Knochenbildung (1)
- Knochenentnahme (1)
- Knochenersatz (1)
- Knorpel (1)
- Knowledge engineering (1)
- Kontaktkraft (1)
- Kopfverletzung (1)
- Koronare Herzkrankheit (1)
- Koronarendoprothese (1)
- Körper (1)
- Körperliche Belastung (1)
- Künstliche Intelligenz (1)
- Laser powder bed fusion (L-PBF) (1)
- Lasers (1)
- Lastverteilung <Statik> (1)
- Le Fort III (1)
- Leg length (1)
- Leistungssportler (1)
- Leitfähgkeit (1)
- Lendenwirbelsäulenkrankheit (1)
- Ligament stiffness (1)
- Linear Models (1)
- Lipofilling (1)
- MAMMAPLASTY (1)
- MDCT (1)
- MECHANICAL PROPERTIES (1)
- MECHANICAL-PROPERTIES (1)
- MEDICINAL PLANTS (1)
- MITOCHONDRIAL DYSFUNCTION (1)
- MOTION (1)
- MRI (1)
- MULTIDETECTOR COMPUTED-TOMOGRAPHY (1)
- Magnesium (1)
- Mammoplastik (1)
- Material properties (1)
- Measurement and testing (1)
- Mechanical Phenomena (1)
- Mechanical behaviour (1)
- Mechanical properties (1)
- Medizintechnik (1)
- Mehrkörpersimulation (1)
- Membrane/classification/standards/statistics & numerical data (1)
- Meniskusschaden (1)
- Mensch (1)
- Mesenchymzelle (1)
- Method labeling (1)
- Micro-structure (1)
- Minimal-invasive Chirurgie (1)
- Modell (1)
- Motion Capture (1)
- Motion Capturing (1)
- Motion capture (1)
- Movement (1)
- Multibody Simulation (1)
- Multiphase blood flow (1)
- Multiresistant (1)
- Mund-Kiefer-Gesichts-Chirurgie (1)
- Muscle (1)
- Muscle influence (1)
- Muscle model (1)
- Muscle trajectory (1)
- Muscle weakness (1)
- Muscles (1)
- Muscoloskeletal model (1)
- Musculoskeletal Simulation (1)
- Musculoskeletal analysis (1)
- Musculoskeletal model (1)
- Musculoskeletal modelling (1)
- Musculoskeletal system (1)
- Muskelkraft (1)
- Muskuloskelettale Simulation (1)
- Nabelvene (1)
- Nachweis (1)
- Nanoparticles (1)
- Non-Newtonian multiphase flow (1)
- Numerische Methode (1)
- OSTEOARTHRITIS (1)
- OUTCOMES (1)
- OXIDATIVE STRESS (1)
- OXYGENATION (1)
- Offset (1)
- Orthopädische Chirurgie (1)
- Osteoconductive (1)
- Osteomyelitis (1)
- Osteosynthese (1)
- Osteotomie (1)
- Outcome (1)
- PCR (1)
- PHOSPHATIDYLCHOLINE (1)
- PLATELET ACTIVATION (1)
- PLATELET-RICH PLASMA (1)
- POLYPHENOLS (1)
- PREDICTOR (1)
- Pandemie (1)
- Parameter study (1)
- Particle Image Velocimetry (1)
- Pelvic ring fracture (1)
- Pelvis (1)
- Perceptual learning (1)
- Percutaneous coronary intervention (1)
- Physiological Breathing (1)
- Polymer (1)
- Polymerase-Kettenreaktion (1)
- Polymers (1)
- Powders (1)
- Precious alloys (1)
- Primary Health Care/statistics & numerical data (1)
- Prognose (1)
- Prosthesis Design (1)
- Prüfung (1)
- Pulleys (1)
- QUANTIFICATION (1)
- RADIATION-THERAPY (1)
- RECIPIENT-SITE (1)
- RTMS (1)
- Radiotherapy (1)
- Randomized (1)
- Rapamycin (1)
- Rapid prototyping (1)
- Reconstruction (1)
- Resilience, psychological (1)
- Resilienz, psychologische (1)
- Resistance to corrosion (1)
- Respiratory Distress Syndrome/therapy (1)
- Restenosis (1)
- Retrospective Studies (1)
- Rind (1)
- Robot sensing systems (1)
- Robotik (1)
- Rotator cuff tears (1)
- Rotatorenmanschettenriss (1)
- SARS-CoV-2 (1)
- SHAPE (1)
- STIFFNESS (1)
- STIMULATION (1)
- Sagittal balance (1)
- Schulkind (1)
- Schädel-Hirn-Trauma (1)
- Second-harmonic generation imaging (1)
- Severity of Illness Index (1)
- Shear Raed Induced Coagulation (1)
- Shear Rate Induced Coagulation (1)
- Shoulder joint (1)
- Shoulder joint complex (1)
- Signals (1)
- Silent Breathing (1)
- Softening (1)
- Specimen preparation and treatment (1)
- Speedcourt (1)
- Spinal fusion (1)
- Spine biomechanics (1)
- Stabilität (1)
- Steifigkeit (1)
- Stent design (1)
- Stent implantation (1)
- Stent screening (1)
- Stent-artery interaction (1)
- Stents (1)
- Stress, Mechanical (1)
- Surface Properties (1)
- Surface treatments (1)
- Surgical smoke (1)
- T-peel configuration (1)
- THR (1)
- THROMBOSIS (1)
- THROMBOTIC DEPOSITS (1)
- TMS (1)
- Task analysis (1)
- Testing biomaterials (1)
- Thoracolumbar spine (1)
- Time factors (1)
- Tinte (1)
- Topographic shift (1)
- Torus (1)
- Total hip athroplasty (1)
- Tracheotomies (1)
- Transfer functions (1)
- Turbulent Kinetic Energy (1)
- Valves (1)
- Vascular injury (1)
- Vergleichende Anatomie (1)
- Verletzung (1)
- Vertebra (1)
- Violinspiel (1)
- Viscoelasticity (1)
- Webcast (1)
- Werkstoff (1)
- Wirbelsäule (1)
- Wirbelsäulenversteifung (1)
- Wrapping (1)
- aerodynamics (1)
- anchorage (1)
- anti-Inflammatory agent (1)
- attention (1)
- biomaterial (1)
- biomechanical implant test (1)
- blood (1)
- bone biomechanics (1)
- brain mapping (1)
- cancer (1)
- cell- free DNA (1)
- cell-enriched lipotransfer (1)
- chemical synthesis (1)
- children (1)
- chondrocytes (1)
- coagulation (1)
- collagen (1)
- combined anteversion (1)
- component position (1)
- computer-assisted orthopaedic surgery (1)
- cortical plasticity (1)
- critical hip joint loading (1)
- crosstalk (1)
- cup loading (1)
- data-driven analysis (1)
- design (1)
- distraction (1)
- drug-eluting stent (1)
- dynamic multiplanar loading (1)
- elbow stability (1)
- electromyography (1)
- embodiment (1)
- emotion (1)
- enhanced resorption (1)
- esb (1)
- extracellular matrix (1)
- fMRI BOLD (1)
- fat grafting (1)
- femoral fracture (1)
- femoral offset (1)
- finite elements analysis (1)
- flexibility ellipsis (1)
- force angles (1)
- force pathways (1)
- form-finding (1)
- functional outcome (1)
- functionality (1)
- gait analysis (1)
- gargle (1)
- gliding flight (1)
- happiness (1)
- high-impact exercisess (1)
- hip contact force (1)
- hip fractureg (1)
- histological evaluation (1)
- human articular cartilage (1)
- human umbilical vein (1)
- humeroradial stability (1)
- hydrogels (1)
- immune system (1)
- implant migration (1)
- inertial measurement units (1)
- infiltration (1)
- inflammation (1)
- influence parameters (1)
- insect flight (1)
- kinematics (1)
- language assessment (1)
- ligaments (1)
- lipoaspirate (1)
- lipograft (1)
- liposomal packing (1)
- lower back load (1)
- lumbar geometry (1)
- lumbar spine (1)
- macular degeneration (1)
- mechanical compliance (1)
- membrane lung (1)
- meniscus (1)
- multifidus (1)
- muscle activity (1)
- muscle injury (1)
- muscle recruitment (1)
- musculoskeletal disease (1)
- musculoskeletal modeling (1)
- musculoskeletal system (1)
- neutrophil extracellular traps (1)
- optical motion capture (1)
- osteoarthritis (1)
- osteoporosis (1)
- pandemic (1)
- patient specific loading (1)
- pelvic floor (1)
- pelvic tilt (1)
- perceptual learning (1)
- pharmacology (1)
- pooling (1)
- proteolysis (1)
- radial head arthroplasty (1)
- radial head prostheses (1)
- range of motion (1)
- rapamycin (1)
- resting-state fMRI (1)
- rheological model (1)
- rim loading (1)
- sadness (1)
- scaffolds (1)
- schools (1)
- sensitivity study (1)
- sensors (1)
- shear induced clotting (1)
- shoulder elevation (1)
- shoulder joint force (1)
- simplified loading model (1)
- sirolimus (1)
- small calibre graft (1)
- sonography (1)
- stent platform (1)
- subject-specific musculoskeletal modeling (1)
- subluxation (1)
- surface electromyography (1)
- surgery (1)
- tannic acid (1)
- task-based fMRI (1)
- tensegrity joint (1)
- therapeutic use (1)
- three-dimensional computed tomography analysis (1)
- tissue engineering (1)
- tissue regeneration (1)
- total hip anthroplasty (1)
- total hip arthroplasty (1)
- toxicity (1)
- tracheobronchial mucus (1)
- vWF (1)
- validation (1)
- vascular tissue engineering (1)
- vector (1)
- violin (1)
- viscoelasticity (1)
- visual cortex (1)
- vitamin C (1)
- von Willebrand factor (1)
- wearable motion-tracking sensors (1)
- white adipose tissue (1)
- zwitterionic monomers (1)
- µCT (1)
Institute
- Fakultät Maschinenbau (275) (remove)
Begutachtungsstatus
- peer-reviewed (98)
- begutachtet (10)
Ergonomic workplaces lead to fewer work-related musculoskeletal disorders and thus fewer sick days. There are various guidelines to help avoid harmful situations. However, these recommendations are often rather crude and often neglect the complex interaction of biomechanical loading and psychological stress. This study investigates whether machine learning algorithms can be used to predict mechanical and stress-related muscle activity for a standardized motion. For this purpose, experimental data were collected for trunk movement with and without additional psychological stress. Two different algorithms (XGBoost and TensorFlow) were used to model the experimental data. XGBoost in particular predicted the results very well. By combining it with musculoskeletal models, the method shown here can be used for workplace analysis but also for the development of real-time feedback systems in real workplace environments.
Biomechanical analysis of the right elevated glenohumeral joint in violinists during legato-playing
(2022)
BACKGROUND:
Many statistics reveal that violin players suffer most often from musculoskeletal disorders compared to musicians of other instrument groups. A common phenomenon, especially observed in violin beginners, is the tendency to elevate the right shoulder during playing the violin. This can probably lead to serious disorders in long-term practice with repetitive movements.
OBJECTIVE:
For this reason, this study investigated the relationship between the right shoulder elevation and the force in the right glenohumeral joint during violin playing. It was hypothesized that the forces in the right glenohumeral joint are higher during playing with the right shoulder raised compared to playing in normal posture.
METHODS:
Motion capture data from four experienced violinists was recorded and processed by means of musculoskeletal simulation to get the force and elevation angle while playing with raised shoulder and in normal position.
RESULTS:
The results indicate that the absolute values of the resulting force, as well as the forces in the mediolateral, inferosuperior, and anteroposterior directions, are higher in playing the violin with the shoulder raised than in a normal posture.
CONCLUSIONS:
Elevating the right shoulder while playing the violin may pose a potential problem.
Objective
The risk of in-stent restenosis can be considerably reduced by stents eluting cytostatic compounds. We created a novel drug-eluting stent system that includes several new features in the rapidly evolving field of stent-based drug delivery.
Methods and Results
The aim of the present study was the preclinical evaluation of a stent-coating system permitting individual, on-site coating of stents with a unique microporous surface allowing for individualizable, dose-adjustable, and multiple coatings with identical or various compounds, designated ISAR (individualizable drug-eluting stent system to abrogate restenosis). Stents were coated with 0.75% rapamycin solution, and high-performance liquid chromatography (HPLC)-based determination of drug release profile indicated drug release for >21 days. Rapamycin-eluting microporous (REMP) stents implanted in porcine coronary arteries were safe. To determine the efficacy of REMP stents, this novel drug-eluting stent platform was compared with the standard sirolimus-eluting stent. At 30 days, in-stent neointima formation in porcine coronary arteries was similar in both groups, yielding a significant decrease of neointimal area and injury-dependent neointimal thickness compared with bare-metal stents.
Conclusion
The ISAR drug-eluting stent platform as a novel concept for stent coating allows for a safe, effective, on-site stent coating process, thus justifying further clinical evaluation to decrease in-stent restenosis in humans.
In-stent neointima formation can be successfully attenuated by drug-eluting stents. We introduce a novel conceptual approach for stent-coating that allows for dose-adjustable, on-site stent coating process if desired with multiple compounds. Microporous stents coated with rapamycin proved safe and effective for the limitation of neointima formation in a porcine coronary stent model.
Aims
Drug-eluting stents (DES) represent a major advance in interventional cardiology. Along with the success shown, current DES also present limitations related to the presence of polymer-coating, fixed drug, and dose used. With the ISAR (Individualized Drug-Eluting Stent System to Abrogate Restenosis) project, a DES system has been developed that permits individualized choice of the drug and dose to use for the given patient. The objective of this prospective dose finding study was to assess the feasibility, safety, and efficacy of a polymer-free on-site stent coating with increasing rapamycin doses.
Methods and results
In this dose finding study, 602 patients were sequentially enrolled in four groups: microporous bare metal stent (BMS), DES stents coated with a 0.5, 1.0, and 2.0% rapamycin solution. The angiographic in-segment restenosis rate at follow-up angiography was the primary study endpoint. In-segment restenosis was significantly reduced from 25.9% with BMS to 18.9, 17.2, and 14.7% with 0.5, 1.0, and 2.0% rapamycin-eluting stents, respectively (P=0.024). Similarly, the need for target lesion revascularization at 1 year follow-up was reduced from 21.5% with BMS to 16.4, 12.6, and 8.8% with 0.5, 1.0, and 2.0% rapamycin-eluting stents, respectively (P=0.006).
Conclusion
The placement of polymer-free stents coated on-site with rapamycin is feasible and safe. Furthermore, a dose-dependent efficacy in restenosis prevention is achievable with this new DES concept.
Vascular damage develops with diverging severity during and after percutaneous coronary intervention with stent placement and is the prevailing stimulus for in-stent restenosis. Previous work has failed to link mechanical data obtained in a realistic in vivo or in vitro environment with data collected during imaging processes. We investigated whether specimens of porcine right coronary arteries soften when indented with a stent strut shaped structure, and if the softening results from damage mechanisms inside the fibrillar collagen structure. To simulate the multiaxial loading scenario of a stented coronary artery, we developed the testing device ‘LAESIO’ that can measure differences in the stress-stretch behavior of the arterial wall before and after the indentation of a strut-like stamp. The testing protocol was optimized according to preliminary experiments, more specifically equilibrium and relaxation tests. After chemical fixation of the specimens and subsequent tissue clearing, we performed three-dimensional surface and second-harmonic generation scans on the deformed specimens. We analyzed and correlated the mechanical response with structural parameters of high-affected tissue located next to the stamp indentation and low-affected tissue beyond the injured area. The results reveal that damage mechanisms, like tissue compression as well as softening, fiber dispersion, and the lesion extent, are direction-dependent, and the severity of them is linked to the strut orientation, indentation pressure, and position. The findings highlight the need for further investigations by applying the proposed methods to human coronary arteries. Additional data and insights might help to incorporate the observed damage mechanisms into material models for finite element analyses to perform more accurate simulations of stent-implantations.
Experimental and mathematical characterization of coronary polyamide-12 balloon catheter membranes
(2020)
The experimental quantification and modeling of the multiaxial mechanical response of polymer membranes of coronary balloon catheters have not yet been carried out. Due to the lack of insights, it is not shown whether isotropic material models can describe the material response of balloon catheter membranes expanded with nominal or higher, supra-nominal pressures. Therefore, for the first time, specimens of commercial polyamide-12 balloon catheters membranes were investigated during uniaxial and biaxial loading scenarios. Furthermore, the influence of kinematic effects on the material response was observed by comparing results from quasi-static and dynamic biaxial extension tests. Novel clamping techniques are described, which allow to test even tiny specimens taken from the balloon membranes. The results of this study reveal the semi-compliant, nonlinear, and viscoelastic character of polyamide-12 balloon catheter membranes. Above nominal pressure, the membranes show a pronounced anisotropic mechanical behavior with a stiffer response in the circumferential direction. The anisotropic feature intensifies with an increasing strain-rate. A modified polynomial model was applied to represent the realistic mechanical response of the balloon catheter membranes during dynamic biaxial extension tests. This study also includes a compact set of constitutive model parameters for the use of the proposed model in future finite element analyses to perform more accurate simulations of expanding balloon catheters.
Background:
Lipofilling is one of the most often performed surgical procedures in plastic and reconstructive surgery. Lipoaspirates provide a ready source of stem cells and secreted factors that contribute to neoangiogenesis and fat graft survival. However, the regulations about the enrichment of these beneficial cells and factors are ambiguous. In this study, the authors tested whether a combination of centrifugation and homogenization allowed the enrichment of viable stem cells in lipoaspirates through the selective removal of tumescent solution, blood, and released lipids without significantly affecting the cell secretome.
Methods:
Human lipoaspirate was harvested from six different patients using water jet–assisted liposuction. Lipoaspirate was homogenized by first centrifugation (3584 rpm for 2 minutes), shear strain (10 times intersyringe processing), and second centrifugation (3584 rpm for 2 minutes). Stem cell enrichment was shown by cell counting after stem cell isolation. Lipoaspirate from different processing steps (unprocessed, after first centrifugation, after homogenization, after second centrifugation) was incubated in serum-free cell culture medium for mass spectrometric analysis of secreted proteins.
Results:
Lipoaspirate homogenization leads to a significant 2.6 ± 1.75-fold enrichment attributable to volume reduction without reducing the viability of the stem cells. Protein composition of the secretome did not change significantly after tissue homogenization. Considering the enrichment effects, there were no significant differences in the protein concentration of the 83 proteins found in all processing steps.
Conclusions:
Stem cells can be enriched mechanically without significantly affecting the composition of secreted proteins. Shear-assisted enrichment of lipoaspirate constitutes no substantial manipulation of the cells’ secretome.
Results of WICOVIR Gargle Pool PCR Testing in German Schools Based on the First 100,000 Tests
(2021)
Background:
Opening schools and keeping children safe from SARS-CoV-2 infections at the same time is urgently needed to protect children from direct and indirect consequences of the COVID-19 pandemic. To achieve this goal, a safe, efficient, and cost-effective SARS-CoV-2 testing system for schools in addition to standard hygiene measures is necessary.
Methods:
We implemented the screening WICOVIR concept for schools in the southeast of Germany, which is based on gargling at home, pooling of samples in schools, and assessment of SARS-CoV-2 by pool rRT-PCR, performed decentralized in numerous participating laboratories. Depooling was performed if pools were positive, and results were transmitted with software specifically developed for the project within a day. Here, we report the results after the first 13 weeks in the project.
Findings:
We developed and implemented the proof-of-concept test system within a pilot phase of 7 weeks based on almost 17,000 participants. After 6 weeks in the main phase of the project, we performed >100,000 tests in total, analyzed in 7,896 pools, identifying 19 cases in >100 participating schools. On average, positive children showed an individual CT value of 31 when identified in the pools. Up to 30 samples were pooled (mean 13) in general, based on school classes and attached school staff. All three participating laboratories detected positive samples reliably with their previously established rRT-PCR standard protocols. When self-administered antigen tests were performed concomitantly in positive cases, only one of these eight tests was positive, and when antigen tests performed after positive pool rRT-PCR results were already known were included, 3 out of 11 truly positive tests were also identified by antigen testing. After 3 weeks of repetitive WICOVIR testing twice weekly, the detection rate of positive children in that cohort decreased significantly from 0.042 to 0.012 (p = 0.008).
Interpretation:
Repeated gargle pool rRT-PCR testing can be implemented quickly in schools. It is an effective, valid, and well-received test system for schools, superior to antigen tests in sensitivity, acceptance, and costs.
Advances in additive manufacturing enable the production of tailored lattice structures and thus, in principle, coronary stents. This study investigates the effects of process-related irregularities, heat and surface treatment on the morphology, mechanical response, and expansion behavior of 316L stainless steel stents produced by laser powder bed fusion and provides a methodological approach for their numerical evaluation. A combined experimental and computational framework is used, based on both actual and computationally reconstructed laser powder bed fused stents. Process-related morphological deviations between the as-designed and actual laser powder bed fused stents were observed, resulting in a diameter increase by a factor of 2-2.6 for the stents without surface treatment and 1.3-2 for the electropolished stent compared to the as-designed stent. Thus, due to the increased geometrically induced stiffness, the laser powder bed fused stents in the as-built (7.11 ± 0.63 N) or the heat treated condition (5.87 ± 0.49 N) showed increased radial forces when compressed between two plates. After electropolishing, the heat treated stents exhibited radial forces (2.38 ± 0.23 N) comparable to conventional metallic stents. The laser powder bed fused stents were further affected by the size effect, resulting in a reduced yield strength by 41% in the as-built and by 59% in the heat treated condition compared to the bulk material obtained from tensile tests. The presented numerical approach was successful in predicting the macroscopic mechanical response of the stents under compression. During deformation, increased stiffness and local stress concentration were observed within the laser powder bed fused stents. Subsequent numerical expansion analysis of the derived stent models within a previously verified numerical model of stent expansion showed that electropolished and heat treated laser powder bed fused stents can exhibit comparable expansion behavior to conventional stents. The findings from this work motivate future experimental/numerical studies to quantify threshold values of critical geometric irregularities, which could be used to establish design guidelines for laser powder bed fused stents/lattice structures.
Biomechanical Analysis of the Right Elevated Glenohumeral Joint in Violinists during Legato-Playing
(2021)
BACKGROUND:
Many statistics reveal that violin players suffer most often from musculoskeletal disorders compared to musicians of other instrument groups. A common phenomenon, especially observed in violin beginners, is the tendency to elevate the right shoulder during playing the violin. This can probably lead to serious disorders in long-term practice with repetitive movements.
OBJECTIVE:
For this reason, this study investigated the relationship between the right shoulder elevation and the force in the right glenohumeral joint during violin playing. It was hypothesized that the forces in the right glenohumeral joint are higher during playing with the right shoulder raised compared to playing in normal posture.
METHODS:
Motion capture data from four experienced violinists was recorded and processed by means of musculoskeletal simulation to get the force and elevation angle while playing with raised shoulder and in normal position.
RESULTS:
The results indicate that the absolute values of the resulting force, as well as the forces in the mediolateral, inferosuperior, and anteroposterior directions, are higher in playing the violin with the shoulder raised than in a normal posture.
CONCLUSIONS: Elevating the right shoulder while playing the violin may pose a potential problem.
Customized additively manufactured (laser powder bed fused (L-PBF)) stents could improve the treatment of complex lesions by enhancing stent-artery conformity. However, geometric irregularities inherent for L-PBF stents are expected to influence not only their mechanical behavior but also their interaction with the artery. In this study, the influence of geometrical irregularities on stent-artery interaction is evaluated within a numerical framework. Thus, computed arterial stresses induced by a reconstructed L-PBF stent model are compared to those induced by the intended stent model (also representing a stent geometry obtained from conventional manufacturing processes) and a modified CAD stent model that accounts for the increased strut thickness inherent for L-PBF stents. It was found that, similar to conventionally manufactured stents, arterial stresses are initially related to the basic stent design/topology, with the highest stresses occurring at the indentations of the stent struts. Compared to the stent CAD model, the L-PBF stent induces distinctly higher and more maximum volume stresses within the plaque and the arterial wall. In return, the modified CAD model overestimates the arterial stresses induced by the L-PBF stent due to its homogeneously increased strut thickness and thus its homogeneously increased geometric stiffness compared with the L-PBF stent. Therefore, the L-PBF-induced geometric irregularities must be explicitly considered when evaluating the L-PBF stent-induced stresses because the intended stent CAD model underestimates the arterial stresses, whereas the modified CAD model overestimates them. The arterial stresses induced by the L-PBF stent were still within the range of values reported for conventional stents in literature, suggesting that the use of L-PBF stents is conceivable in principle. However, because geometric irregularities, such as protruding features from the stent surface, could potentially damage the artery or lead to premature stent failure, further improvement of L-PBF stents is essential.
Regarding the prevention of injuries and rehabilitation of the human hand, musculoskeletal simulations using an inverse dynamics approach allow for insights of the muscle recruitment and thus acting forces on the hand. Currently, several hand models from various research groups are in use, which are mainly validated by the comparison of numerical and anatomical moment arms. In contrast to this validation and model-building technique by cadaver studies, the aim of this study is to further validate a recently published hand model [1] by analyzing numerically calculated muscle activities in comparison to experimentally measured electromyographical signals of the muscles. Therefore, the electromyographical signals of 10 hand muscles of five test subjects performing seven different hand movements were measured. The kinematics of these tasks were used as input for the hand model, and the numerical muscle activities were computed. To analyze the relationship between simulated and measured activities, the time difference of the muscle on- and off-set points was calculated, which resulted in a mean on- and off-set time difference of 0.58 s between the experimental data and the model. The largest differences were detected for movements that mainly addressed the wrist. One major issue comparing simulated and measured muscle activities of the hand is cross-talk. Nevertheless, the results show that the hand model fits the experiment quite accurately despite some limitations and is a further step toward patient-specific modeling of the upper extremity.
Musculoskeletal lower back load of accoucheurs during childbirth – A pilot and feasibility study
(2021)
Introduction: Back problems represent one of the leading causes of accouchers' work-related musculoskeletal morbidities. The correct execution of birth-related maneuvers including manual perineal protection is crucial not only for the mother and child but also for obstetricians and midwives to reduce any strain on their musculoskeletal system. Therefore, the overall aim of this study was to test the feasibility of determining the effect of different accouchers' postures (standing and kneeling) on their musculoskeletal system.
Methods: The biomechanical analysis is based on musculoskeletal simulations that included motion recordings of real deliveries as well as deliveries conducted on a birthing simulator. These simulations were then used to determine individual joints' loads.
Results: In the kneeling posture, both a low intra-operator variability and a lower average maximum load of the lower back was observed. For the standing position the spine load was reduced by pivoting the elbow on the accouchers' thigh, which in turn was associated with a significantly greater load on the shoulder joint.
Conclusion: The study demonstrated the feasibility of our technique to assess joints loads. It also provided initial data indicating that a posture that reduces spinal flexion and tilt, achieved in this study by the kneeling, can significantly reduce the strain on the practitioner's musculoskeletal system.
Football players have a high risk of leg muscle injuries, especially when exposed to mental stress. Injuries to muscles of the thigh are common in amateur and professional football, representing almost a third of all injuries. These injuries occur primarily in non-contact situations and from overuse. They can lead to a range of costs, including financial costs associated with treatment as well as those associated with long-term recovery, and absence from training and/or competition. Further, there is a high risk of injury recurrence and subsequent injury.
With the progress in modern medicine, it was possible to significantly reduce the risks of birth for mother and child. One aspect that has received less attention so far is the risk of injury to the accoucheurs (obstetricians and midwives) during the birth process. Indeed, studies indicate that 92% of midwives suffer from musculoskeletal disorders, with the lower back being the main cause of complaints (72%). The aim of this study was to investigate two commonly used postural techniques used by accoucheurs during childbirth and to analyze the resulting load on the lower back using the AnyBodyTM musculoskeletal simulation software.
Evaluation of muscle recruitment and muscle models in musculoskeletal simulation of dynamic motion
(2021)
Musculoskeletal simulation plays an increasingly important role in sports biomechanics. In the last years, the field of application widened from orthopaedics and ergonomics to sports [1]. A muscle recruitment algorithm with a quadratic objective function is usually used to calculate muscle activity in dynamic movements. The agreement of calculated and measured thigh muscle activity has already been investigated [2]. They found a strong agreement for sprinting and running, while the correlation decreased for side-cutting manoeuvres. Nevertheless, the influence of different muscle recruitment criteria on muscle activity in dynamic musculoskeletal simulations is currently unknown. Hence, this study aimed to analyse the effect of different muscle recruitment criteria and muscle models on the correlation of numerical and measured muscle activity in highly dynamic movements.
Outputs of musculoskeletal models should be considered probabilistic rather than deterministic as they are affected by inaccuracies and estimations associated with the development of the model. One of these uncertainties being critical for modeling arises from the determination of the muscles' line of action and the physiological cross-sectional area. Therefore, the aim of this study was to evaluate the outcome sensitivity of model predictions from a musculoskeletal hand model in comparison to the uncertainty of these input parameters. For this purpose, the kinematics and muscle activities of different hand movements (abduction of the fingers, abduction of the thumb, and flexion of the thumb) were recorded. One thousand simulations were calculated for each movement using the Latin hypercube sampling method with a corresponding variation of the muscle origin/insertion points and the cross-sectional area. Comparing the standard hand to simulations incorporating uncertainties of input parameters shows no major deviations in on- and off-set time point of muscle activities. About 60% of simulations are located within a ± 30% interval around the standard model concerning joint reaction forces. The comparison with the variation of the input data leads to the conclusion that the standard hand model is able to provide not over-scattered outcomes and, therefore, can be considered relatively stable. These results are of practical importance to the personalization of a musculoskeletal model with subject-specific bone geometries and hence changed muscle line of action.
Static pelvic tilt impacts functional cup position in total hip arthroplasty (THA). In the current study we investigated the effect of kinematic pelvic changes on cup position. In the course of a prospective controlled trial postoperative 3D-computed tomography (CT) and gait analysis before and 6 and 12 months after THA were obtained in 60 patients. Kinematic pelvic motion during gait was measured using Anybody Modeling System. By fusion with 3D-CT, the impact of kinematic pelvic tilt alterations on cup anteversion and inclination was calculated. Furthermore, risk factors correlating with high pelvic mobility were evaluated. During gait a high pelvic range of motion up to 15.6° exceeding 5° in 61.7% (37/60) of patients before THA was found. After surgery, the pelvis tilted posteriorly by a mean of 4.0 ± 6.6° (p < .001). The pelvic anteflexion led to a mean decrease of −1.9 ± 2.2° (p < .001) for cup inclination and −15.1 ± 6.1° (p < .001) for anteversion in relation to the anterior pelvic plane (APP). Kinematic pelvic changes resulted in a further change up to 2.3° for inclination and up to 12.3° for anteversion. In relation to the preoperative situation differences in postoperative cup position ranged from −4.4 to 4.6° for inclination and from −7.8 to 17.9° for anteversion, respectively. Female sex (p < .001) and normal body weight (p < .001) correlated with high alterations in pelvic tilt. Kinematic pelvic changes highly impact cup anteversion in THA. Surgeons using the APP as reference should aim for a higher anteversion of about 15° due to the functional anteflexion of the pelvis during gait.