Refine
Year of publication
Institute
Document Type
- Article (536) (remove)
Keywords
- Einspielen <Werkstoff> (7)
- FEM (4)
- Finite-Elemente-Methode (4)
- CellDrum (3)
- shakedown analysis (3)
- Einspielanalyse (2)
- Lipopolysaccharide (2)
- Shakedown analysis (2)
- Stiffness (2)
- Traglastanalyse (2)
- bacterial cellulose (2)
- carbonized rice husk (2)
- damage (2)
- limit analysis (2)
- locomotion (2)
- muscle fascicle behavior (2)
- prebiotic (2)
- shakedown (2)
- ultrasound (2)
- ultrasound imaging (2)
- Achilles tendon (1)
- Adaptive control (1)
- Ageing (1)
- Air purification (1)
- AlterG (1)
- Alternating plasticity (1)
- Alzheimer's disease (1)
- Analysis (1)
- Analytischer Zulaessigkeitsnachweis (1)
- Anastomotic leakage (1)
- Anatomy (1)
- Annulus Fibrosus (1)
- Antarctic Glaciology (1)
- Architectural gear ratio (1)
- Arthosetherapie (1)
- Assistive technology (1)
- Aufschlagversuch (1)
- Autolysis (1)
- Automatic control (1)
- Axialbelastung (1)
- Axially cracked pipe (1)
- Bacillus sp (1)
- Bacterial cellulose (1)
- Basis Reduktion (1)
- Basis reduction (1)
- Bicharakteristikenverfahren (1)
- Biocomposites (1)
- Biomechanical simulation (1)
- Bioreaktor (1)
- Biosolubilization (1)
- Blutzellenlagerung (1)
- Bone quality and biomechanics (1)
- Carbon sources (1)
- Cardiac myocytes (1)
- Cardiac tissue (1)
- Cell permeability (1)
- Cellular force (1)
- Cellulose nanostructure (1)
- Cement infiltration (1)
- Cementoblast (1)
- Circular Dichroism (1)
- Clusterion (1)
- Compression (1)
- Computational biomechanics (1)
- Constitutive model (1)
- Contractile tension (1)
- Convex optimization (1)
- Cost-effectiveness (1)
- Culture media (1)
- DLR-ESTEC GOSSAMER roadmap for solar sailing (1)
- Damage mechanics theory (1)
- Decomposition (1)
- Deformation (1)
- Design-by-analysis (1)
- Disc Degeneration (1)
- Discontinuous fractures (1)
- Distorsion des oberen Sprunggelenks (1)
- Druckbeanspruchung (1)
- Druckbehälter (1)
- Druckbelastung (1)
- Druckgeräte (1)
- Drug simulation (1)
- ELISA (1)
- ES-FEM (1)
- Einspiel-Analyse (1)
- Einspiel-Kriterium (1)
- Einspielen (1)
- Elastizität (1)
- Electromechanical modeling (1)
- End-to-end colorectal anastomosis (1)
- Endothelial cells (1)
- Endothelial dysfunction (1)
- Environmental impact (1)
- Enzyme-linked immunosorbent assay (1)
- Epithel (1)
- Experiment (1)
- External knee adduction moments (1)
- Extraterrestrial Glaciology (1)
- FS-FEM (1)
- Fehlerstellen (1)
- Fibroblast (1)
- Finite element analysis (1)
- Finite element modelling (1)
- Fließgrenze (1)
- Forces (1)
- Fracture configuration (1)
- Fracture simulation (1)
- Freeze–thaw process (1)
- Frequency adaption (1)
- Fußball (1)
- GOSSAMER-1 (1)
- Geriatric (1)
- Glaciological instruments and methods (1)
- Glaucoma (1)
- Global and local collapse (1)
- Gonarthrose (1)
- Grenzwertberechnung (1)
- Haemodialysis (1)
- Handbike (1)
- Harnleiter (1)
- Heart tissue culture (1)
- Hemoglobin structure (1)
- Hip fractures (1)
- Hodgkin–Huxley models (1)
- Homogenization (1)
- Human-Computer interaction (1)
- Hämoglobin (1)
- Hämoglobinstruktur (1)
- Induced pluripotent stem cells (1)
- Inotropic compounds (1)
- Interstellar objects (1)
- Intervertebral Disc (1)
- Intradiscal Pressure (1)
- Inverse dynamic problem (1)
- Inverse kinematic problem (1)
- Ion channels (1)
- Iterative learning control (1)
- Kniegelenkarthrose (1)
- Knochen (1)
- Knochenbildung (1)
- Knochenchirugie (1)
- Knochendichte (1)
- Kohlenstofffaser (1)
- LPS (1)
- Lactobacillus rhamnosus GG (1)
- Limit analysis (1)
- Liver (1)
- Long COVID (1)
- Luftreiniger (1)
- MBST (1)
- Machine learning (1)
- Manipulated variables (1)
- Materialermüdung (1)
- Mechanotransduction (1)
- Medusomyces gisevi (1)
- Microcirculation (1)
- Mild cognitive impairment (1)
- Missions (1)
- Muscle (1)
- Muscle Fascicle (1)
- Muscle Force (1)
- Musculoskeletal model (1)
- Musculoskeletal system (1)
- Myocardial infarction and cardiac death (1)
- NONOate (1)
- Natural fibres (1)
- Nitric Oxide (1)
- Nitric Oxide Donor (1)
- Non-parallel fissures (1)
- Nucleus Pulposus (1)
- Ocular blood flow (1)
- Organkultur (1)
- Osteoporose (1)
- Osteoporosis (1)
- Paralympic sport (1)
- Permeability (1)
- Permeabilität (1)
- Peroxidase (1)
- Pflanzenphysiologie (1)
- Pflanzenscanner (1)
- Pflanzenstress (1)
- Pharmacology (1)
- Physiology (1)
- Plasmacluster ion technology (1)
- Plastizität (1)
- Polymer-matrix composites (1)
- Post-COVID-19 syndrome (1)
- Pressure loaded crack-face (1)
- Prevention (1)
- Progressive plastic deformation (1)
- Prophylaxis (1)
- Proximal humerus fracture (1)
- Pulsations (1)
- RVA (1)
- Ratchetting (1)
- Raumluft (1)
- Recombinant activated protein C (1)
- Red blood cell storage (1)
- Rehabilitation Technology and Prosthetics (1)
- Rehabilitation engineering (1)
- Retinal vessel analysis (1)
- Retinal vessels (1)
- Robotic rehabilitation (1)
- Rohr (1)
- Rohrbruch (1)
- Rotator cuff (1)
- Running (1)
- S-FEM (1)
- Schienbeinschoner (1)
- Schwammknochen (1)
- Septic cardiomyopathy (1)
- Shakedown (1)
- Shakedown criterion (1)
- Simulation (1)
- Skeletal muscle (1)
- Small Aral Sea (1)
- Small spacecraft (1)
- Solar sail (1)
- Spleen (1)
- Sprunggelenkorthesen (1)
- Stahl (1)
- Stress concentrations (1)
- Strukturanalyse (1)
- Subclacial exploration (1)
- Subglacial lakes (1)
- SunRav BookEditor (1)
- Surgical Navigation and Robotics (1)
- Surgical staplers (1)
- Temperaturabhängigkeit (1)
- Tendon Rupture (1)
- Tendon properties (1)
- Tendons (1)
- Tension (1)
- Tissue Engineering (1)
- Traglast (1)
- Trajectories (1)
- Ultrasound (1)
- Uniaxial compression test (1)
- Variable height stapler design (1)
- Vascular response (1)
- Vasomotions (1)
- Vertebroplastie (1)
- Vertebroplasty (1)
- Viscous flow (1)
- Viskose Strömung (1)
- Viskosität (1)
- Visual field asymmetry (1)
- Wolff's Law (1)
- Wolffsches Gesetz (1)
- Wundheilung (1)
- Zug-Druck Belastung (1)
- achilles tendon (1)
- actin cytoskeleton (1)
- adipose-derived stromal cells (ASCs) (1)
- adsorption (1)
- agility (1)
- alternierend Verformbarkeit (1)
- anaesthetic complications (1)
- anisotropy (1)
- ankle braces (1)
- ankle sprain (1)
- aortic perfusion (1)
- aromatic amines (1)
- arthrosis therapy (1)
- biaxial tensile experiment (1)
- bicharacteristics (1)
- biofilms (1)
- biomechanics (1)
- biopotential electrodes (1)
- bone density (1)
- bone structure (1)
- burst pressure (1)
- burst tests (1)
- cancellous bone (1)
- cardiomyocyte biomechanics (1)
- cell aerosolization (1)
- cell atomization (1)
- cerebral small vessel disease (1)
- chance constrained programming (1)
- coculture (1)
- cognitive impairment (1)
- community dwelling (1)
- computational fluid dynamics analysis (1)
- connective tissue (1)
- constitutive modeling (1)
- constructive alignment (1)
- correlation (1)
- crop yield (1)
- dental trauma (1)
- dialysis (1)
- difficult airway (1)
- direct method (1)
- distance learning (1)
- distorted element (1)
- double-lumen tube intubation (1)
- drop jump (1)
- e-books (1)
- e-issues (1)
- ecological structure (1)
- elastic solids (1)
- electromyography (1)
- endoluminal (1)
- energy absorption (1)
- energy dissipation (1)
- epithelization (1)
- examination (1)
- exopolysaccharides (1)
- extracorporeal membrane oxygenation (1)
- fatigue analyses (1)
- fibulare Bandruptur (1)
- flaw (1)
- force generation (1)
- forehead EEG (1)
- fortschreitende plastische Deformation (1)
- gait (1)
- gonarthrosis (1)
- healthy aging (1)
- hiPS cardiomyocytes (1)
- high-intensity exercise (1)
- human dermal fibroblasts (1)
- humic acid (1)
- hyper-gravity (1)
- hyperelastic (1)
- hypo-gravity (1)
- immobilization (1)
- impedance spectroscopy (1)
- in-ear EEG (1)
- intraclass correlation coefficient (1)
- konvexe Optimierung (1)
- lignite (1)
- limit load (1)
- lipopolysaccharide (1)
- lipopolysaccharides (1)
- load limit (1)
- long-term retention (1)
- low-rank coal (1)
- mechanical buffer (1)
- metagenomics (1)
- microbial diversity (1)
- multimodal (1)
- muscle mechanics (1)
- nanostructured carbonized plant parts (1)
- nanostrukturierte carbonisierte Pflanzenteile (1)
- naphtols (1)
- non-simplex S-FEM elements (1)
- overload (1)
- parabolic flight (1)
- performance testing (1)
- phenols (1)
- physiology (1)
- pipes (1)
- plant scanner (1)
- plant stress (1)
- practical learning (1)
- prevention (1)
- psychosocial (1)
- pullulan (1)
- ratchetting (1)
- rehabilitation (1)
- reliability analysis (1)
- reliability of structures (1)
- retinal microvasculature (1)
- retinal vessels (1)
- running (1)
- rupture of the fibular ligament (1)
- sEMG (1)
- sarcomere operating length (1)
- series elastic element behavior (1)
- shakedown analyses (1)
- shotgun sequencing (1)
- shoulder (1)
- simulation (1)
- smooth muscle contraction (1)
- softs (1)
- soil amendment (1)
- soil health (1)
- soil remediation (1)
- sprint start (1)
- standard error of measurement (1)
- stiffness (1)
- stochastic programming (1)
- strain energy function (1)
- stretch reflex (1)
- stretch-shortening cycle (1)
- surface modification (1)
- survival (1)
- tendon rupture (1)
- tension–torsion loading (1)
- test-retest reliability (1)
- thermal ratcheting (1)
- tri-lineage differentiation (1)
- twin-fluid atomizer (1)
- ultrasonography (1)
- unloading (1)
- vessels (1)
- videolaryngoscopy (1)
- virgin passive (1)
- viscoelasticity (1)
- walking (1)
- walking gait (1)
- wound healing (1)
- yield stress (1)
Hintergrund
Die Anwendung und das Verständnis von Statistik sind sehr wichtig für die biomedizinische Forschung und für die klinische Praxis. Dies gilt insbesondere auch zur Abschätzung der Möglichkeiten unterschiedlichster Diagnostik- und Therapieoptionen beim Glaukom. Die scheinbare Komplexität der Statistik, die zum Teil dem „gesunden Menschenverstand“ zu widersprechen scheint, zusammen mit der nur vorsichtigen Akzeptanz der Statistik bei vielen Medizinern können zu bewussten und unbewussten Manipulationen bei der Datendarstellung und -interpretation führen.
Ziel der Arbeit
Ziel ist die verständliche Darstellung einiger typischer Fehler in der medizinisch-statistischen Datenbehandlung.
Material und Methoden
Anhand hypothetischer Beispiele aus der Glaukomdiagnostik erfolgen die Darstellung der Wirkung eines hypotensiven Medikamentes sowie die Beurteilung der Ergebnisse eines diagnostischen Tests. Es werden die typischsten statistischen Einsatzbereiche und Irrtumsquellen ausführlich und verständlich analysiert
Ergebnisse
Mechanismen von Datenmanipulation und falscher Dateninterpretation werden aufgeklärt. Typische Irrtumsquellen bei der statistischen Auswertung und Datendarstellung werden dabei erläutert.
Schlussfolgerungen
Die erläuterten praktischen Beispiele zeigen die Notwendigkeit, die Grundlagen der Statistik zu verstehen und korrekt anwenden zu können. Fehlendes Grundlagenwissen und Halbwissen der medizinischen Statistik können zu folgenschweren Missverständnissen und falschen Entscheidungen in der medizinischen Forschung, aber auch in der klinischen Praxis führen.
Retinal Vessel Analysis (RVA) in the context of subarachnoid hemorrhage: A proof of concept study
(2016)
Background
Timely detection of impending delayed cerebral ischemia after subarachnoid hemorrhage (SAH) is essential to improve outcome, but poses a diagnostic challenge. Retinal vessels as an embryological part of the intracranial vasculature are easily accessible for analysis and may hold the key to a new and non-invasive monitoring technique. This investigation aims to determine the feasibility of standardized retinal vessel analysis (RVA) in the context of SAH.
Methods
In a prospective pilot study, we performed RVA in six patients awake and cooperative with SAH in the acute phase (day 2–14) and eight patients at the time of follow-up (mean 4.6±1.7months after SAH), and included 33 age-matched healthy controls. Data was acquired using a manoeuvrable Dynamic Vessel Analyzer (Imedos Systems UG, Jena) for examination of retinal vessel dimension and neurovascular coupling.
Results
Image quality was satisfactory in the majority of cases (93.3%). In the acute phase after SAH, retinal arteries were significantly dilated when compared to the control group (124.2±4.3MU vs 110.9±11.4MU, p<0.01), a difference that persisted to a lesser extent in the later stage of the disease (122.7±17.2MU, p<0.05). Testing for neurovascular coupling showed a trend towards impaired primary vasodilation and secondary vasoconstriction (p = 0.08, p = 0.09 resp.) initially and partial recovery at the time of follow-up, indicating a relative improvement in a time-dependent fashion.
Conclusion
RVA is technically feasible in patients with SAH and can detect fluctuations in vessel diameter and autoregulation even in less severely affected patients. Preliminary data suggests potential for RVA as a new and non-invasive tool for advanced SAH monitoring, but clinical relevance and prognostic value will have to be determined in a larger cohort.
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.
Mit modernen nicht invasiven bildgebenden Verfahren lassen sich anhand der Fundusfotografie bzw. der optischen Verfilmung Aspekte der funktionellen und strukturellen retinalen Gefäßveränderungen objektiv untersuchen. Der Zustand und das Verhalten retinaler Gefäße beeinflussen im prä-, post- und kapillaren Bereich den Blutfluss und strömungsbedingte Stoffwechselverhältnisse passiv und aktiv über den Gefäßdurchmesser. Retinale Gefäße gleichen von Aufbau und Funktion den zerebralen Gefäßen und spiegeln den Zustand der Mikrozirkulation wider. Mithilfe von aus den Gefäßweiten berechneten Biomarkern soll eine Aussage über die Prognose von systemischen vaskulär bedingten Erkrankungen getroffen werden. Die statische retinale Gefäßanalyse befasst sich mit der Untersuchung des Zustandes der prä- und postkapillaren Gefäßdurchmesser der retinalen Mikrozirkulation anhand einer optischen Fundusaufnahme. Bei der dynamischen retinalen Gefäßanalyse wird der Längsschnitt eines retinalen Gefäßes nicht invasiv funktionell und strukturell über einen Zeitraum vor, während und nach einer spezifischen vaskulären Stimulation untersucht. Die genaue Methodologie der Auswertung und die Bezeichnung der Parameter variieren bei unterschiedlichen Ansätzen. Mittels retinaler Gefäßanalyse wurden bislang mehrere klinische Querschnitts- und Interventionsstudien in der Augenheilkunde und anderen Fachgebieten, inkl. Kardiologie, Neurologie, Neurochirurgie, Nephrologie, Gynäkologie, Sportmedizin, Diabetologie, Hypertensiologie usw. durchgeführt. Mit der statischen retinalen Gefäßanalyse steht eine kostengünstige, reproduzierbare, nicht invasive Screeningtechnik zur Verfügung, um eine prognostische Aussage über die Gefäßgesundheit eines individuellen Patienten zu treffen. Die dynamische retinale Gefäßanalyse besitzt ein weiteres diagnostisches Anwendungsspektrum als die statische, da sie das Verhalten retinaler Gefäße zeitkontinuierlich untersucht. Die Evaluation vaskulärer Erkrankungen sowie zerebro- bzw. kardiovaskulärer Morbidität und Mortalität mittels mehrerer methodologischer Modalitäten retinaler Gefäßanalyse mit ihren jeweiligen quantitativen Biomarkern bietet eine zukunftsträchtige diagnostische Perspektive. Die interdisziplinäre klinische Anwendung dieser vaskulären Biomarker gewinnt zunehmend an Bedeutung, sowohl in der Augenheilkunde als auch in anderen Fachgebieten.
Altered neurovascular coupling as measured by optical imaging: a biomarker for Alzheimer’s disease
(2017)
False spectra formation in the differential two-channel scheme of the laser Doppler flowmeter
(2018)
Noise in the differential two-channel scheme of a classic laser Doppler flowmetry (LDF) instrument was studied. Formation of false spectral components in the output signal due to beating of electrical signals in the differential amplifier was found out. The improved block-diagram of the flowmeter was developed allowing to reduce the noise.
Background
Impairment of neurovascular coupling (NVC) was recently reported in the context of subarachnoid hemorrhage and may correlate with disease severity and outcome. However, previous techniques to evaluate NVC required invasive procedures. Retinal vessels may represent an alternative option for non-invasive assessment of NVC.
Methods
A prototype of an adapted retinal vessel analyzer was used to assess retinal vessel diameter in mice. Dynamic vessel analysis (DVA) included an application of monochromatic flicker light impulses in predefined frequencies for evaluating NVC. All retinae were harvested after DVA and electroretinograms were performed.
Results
A total of 104 retinal scans were conducted in 21 male mice (90 scans). Quantitative arterial recordings were feasible only in a minority of animals, showing an emphasized reaction to flicker light impulses (8 mice; 14 scans). A characteristic venous response to flicker light, however, could observed in the majority of animals. Repeated measurements resulted in a significant decrease of baseline venous diameter (7 mice; 7 scans, p < 0.05). Ex-vivo electroretinograms, performed after in-vivo DVA, demonstrated a significant reduction of transretinal signaling in animals with repeated DVA (n = 6, p < 0.001).
Conclusions
To the best of our knowledge, this is the first non-invasive study assessing murine retinal vessel response to flicker light with characteristic changes in NVC. The imaging system can be used for basic research and enables the investigation of retinal vessel dimension and function in control mice and genetically modified animals.