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- Natural language processing (5)
- LAPS (4)
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Purpose — to compare the chemical elemental composition of vitreous cavity content taken from cadaveric eyes compared to samples taken from the eyes with terminal stage refractory glaucoma with decompensated intraocular pressure (IOP). Material and methods. The vitreous contents of the eyes from 2 groups were studied. The 1st group included 15 cadaveric eyes; the 2nd group included 15 eyes with refractory glaucoma in the terminal stage of the disease with decompensated IOP in patients with hypertension pain. The vitreal content samples were taken in the course of antiglaucoma surgery aimed at preserving the eye as an organ and involving employment of drainage in the vitreous cavity. The study of virtual contents was carried out on energy dispersive spectrometer Oxford X-Max 50 integrated into scanning electron microscope Zeiss EVO LS10. Results. Increased concentrations of Kalium and Phosphorus were detected in the vitreous content of cadaveric eyes compared with the vitreal content from the eyes with terminal glaucoma with decompensated IOP taken in vivo (K — 0.172/0.093; P — 0.045/0.025 mmol/L). In the vitreous cavity in the eyes with end-stage glaucoma with decompensated IOP, the concentration of Nitrogen was higher in comparison with human cadaver eyes (2.030/1.424 mmol/L). Conclusion. The increased concentrations of Kalium and Phosphorus in the vitreous content of cadaveric eyes is associated with postmortem autolytic processes and with the release of intracellular content in the destruction of cell membranes. The increased Nitrogen concentration in the vitreal contents of the eyes with terminal stage glaucoma with decompensated IOP may be associated with the presence of osmotically active nitrogen-containing compounds in the eyes with increased IOP.
Über die Äquivalenz zweier Transmissionsrandwertprobleme aus der elektromagnetischen Streutheorie
(1994)
Für die Approximation stetiger, 2π-periodischer Funktionen auf der reellen Achse durch trigonometrische Polynome wurde ein direkter Satz von D. Jackson 1911 [8] und die Umkehrung von S. N. Bernstein 1912 [1] bewiesen und die Ergebnisse von A. Zygmund [25] 1945 verallgemeinert. 1949 stellte M. Zamansky [25] eine Beziehung zwischen der Approximationsordnung und dem Wachstum bezϋglich n der Ableitungen der Approximationspolynome her; auf die Approximationsordnung für die Ableitungen der Funktion schloβ S. B. Steckin 1951.
Die Umkehrung des Ergebnisses von M. Zamansky bewies G. Sunouchi 1968 [21,22], womit die Aquivalenz aller Aussagen gezeigt ist.
Die Übertragung der Ergebnisse auf Approximationsoperatoren in Banachräumen stammt von K. Scherer und P. L. Butzer [3, 4], wobei gewisse Voraussetzungen an die Operatorfolge (eine verallgemeinerte Bernsteinsche Ungleichung und eine sogenannte Jacksonsche Ungleichung) gestellt werden. An die Stelle der strukturellen Eigenschaften der Funktion, die durch das Verhalten des Stetigkeitsmoduls der Funktion charakterisiert werden, treten in allgemeinen Banachräumen Eigenschaften des von J. Peetre [17] eingefϋhrten K-Funktionals.
In dieser Arbeit wird die Approximation von Funktionen, die auf der Einheitskugel Sᵏ im Rᵏ definiert sind, durch Linearkombinationen von Kugelfunktionen untersucht. Es wird für diesen Fall eine Bernstein-Ungleichung und die Jackson-Ungleichung bewiesen, wenn man die Ableitung durch den Laplace-Operator auf Sᵏ ersetzt. Damit ist der oben zitierte allgemeine Satz von Butzer-Scherer anwendbar. Weiter kann man hier an Stelle des K-Funktionals einen verallgemeinerten Stetigkeitsmodul setzen. Anschlieβend wird der Spezialfall der zonalen Funktionen und ihre Approximation durch algebraische Polynome untersucht.
Über den Relaxationseinfluß auf die Stabilität der ebenen Couette-Strömung. Akbay, U. ; Sponagel, S.
(1984)
Zielführend moderieren
(2022)
In der Teamarbeit wird Moderation zum Erfolgsfaktor, der jedoch häufig unterschätzt wird. Ausgehend vom persönlichen Kompetenzniveau verknüpft dieses Buch Grundlagen und Methoden zu Wegen, um Ihre persönliche Entwicklung individuell zu begleiten: Neulinge finden hilfreiche Checklisten und Basistechniken für ihre ersten Moderationen, Fortgeschrittene wertvolle Praxistipps und Methoden für den Ausbau ihrer Moderationskompetenz. Profis schließlich genießen eine raffinierte Aussicht auf weniger bekannte Techniken und neue Anwendungen. Weiterführende Exkurse zum Meeting-Management und zur Online-Moderation runden den Anwendungshorizont ab.
Ob in Beruf, Studium oder Ehrenamt – derart ausgestattet gelingen Ihre eigene sowie die Entwicklung Ihres Teams durch zielführende Moderationen.
The isotopes ¹³⁰,¹³²,¹³⁴,¹³⁶ Ce are investigated by means of the reactions ¹¹⁸,¹²⁰,¹²²,¹²⁴ Sn(¹⁶O, 4n) at bombarding energies between 68 and 76 MeV. From lifetime measurements a reduction of the collective behaviour is observed with increasing neutron number. Yrast cascades of rotational structure are identified up to angular momenta I=16⁺ or I=18⁺ in ¹³⁰,¹³²,¹³⁴ Ce. These cascades show a strong “back-bending” effect. In ¹³⁶ Ce no such simple yrast cascade could be found.
Wind is closely associated with the discussion of fairness in ski jumping. To counter-act its influence on the jump length, the International Ski Federation (FIS) has introduced a wind compensation approach. We applied three differently accurate computer models of the flight phase with wind (M1, M2, and M3) to study the jump length effects of various wind scenarios. The previously used model M1 is accurate for wind blowing in direction of the flight path, but inaccuracies are to be expected for wind directions deviating from the tangent to the flight path. M2 considers the change of airflow direction, but it does not consider the associated change in the angle of attack of the skis which additionally modifies drag and lift area time functions. M3 predicts the length effect for all wind directions within the plane of the flight trajectory without any mathematical simplification. Prediction errors of M3 are determined only by the quality of the input data: wind velocity, drag and lift area functions, take-off velocity, and weight. For comparing the three models, drag and lift area functions of an optimized reference jump were used. Results obtained with M2, which is much easier to handle than M3, did not deviate noticeably when compared to predictions of the reference model M3. Therefore, we suggest to use M2 in future applications. A comparison of M2 predictions with the FIS wind compensation system showed substantial discrepancies, for instance: in the first flight phase, tailwind can increase jump length, and headwind can decrease it; this is opposite of what had been anticipated before and is not considered in the current wind compensation system in ski jumping.
Weak Representation of the Cumulative Hazard Function under Semiparametric Random Censorship Models
(2001)
Die Erfindung betrifft eine Vorrichtung zur Messung biomedizinischer Daten eines Probanden, mit einem Messsystem zur Erhebung der Daten sowie einer ersten Hardware-Komponente zur Aufzeichnung der Daten. In einer Verbindungsleitung zur Übertragung der Daten vom Messsystem zur ersten Hardware-Komponente zur Aufzeichnung der Daten ist erfindungsgemäss ein Mittel zur galvanischen Auftrennung der Daten angeordnet. Auf diese Weise ist wenigstens die Duplizierung der Daten für Datenverarbeitungszwecke gewährleistet. Die auf diese Weise verarbeiteten Daten werden für ein Verfahren zur Echtzeit-Stimulation eines Probanden genutzt.
Die vorliegende Erfindung betrifft eine Vorrichtung zum Halten eines lebenden Objektes bei physiologischen Messungen mit einem Basiselement und Mitteln zum Arretieren des lebenden Objektes, die atraumatische Ohrenhalter sowie ein Mundstück aufweisen, das mit einer Aussparung für die Zähne des Lebewesens versehen ist, mit einem Masseanteil von wenigstens 95% an glasfaserverstärktem Kunststoff.
There is a growing body of evidence for the effects of vitamin D on intestinal host-microbiome interactions related to gut dysbiosis and bowel inflammation. This brief review highlights the potential links between vitamin D and gut health, emphasizing the role of vitamin D in microbiological and immunological mechanisms of inflammatory bowel diseases. A comprehensive literature search was carried out in PubMed and Google Scholar using combinations of keywords “vitamin D,” “intestines,” “gut microflora,” “bowel inflammation”. Only articles published in English and related to the study topic are included in the review. We discuss how vitamin D (a) modulates intestinal microbiome function, (b) controls antimicrobial peptide expression, and (c) has a protective effect on epithelial barriers in the gut mucosa. Vitamin D and its nuclear receptor (VDR) regulate intestinal barrier integrity, and control innate and adaptive immunity in the gut. Metabolites from the gut microbiota may also regulate expression of VDR, while vitamin D may influence the gut microbiota and exert anti-inflammatory and immune-modulating effects. The underlying mechanism of vitamin D in the pathogenesis of bowel diseases is not fully understood, but maintaining an optimal vitamin D status appears to be beneficial for gut health. Future studies will shed light on the molecular mechanisms through which vitamin D and VDR interactions affect intestinal mucosal immunity, pathogen invasion, symbiont colonization, and antimicrobial peptide expression.
Vitamin D plays an essential role in calcium and inorganic phosphate (Pi) homeostasis, maintaining their optimal levels to assure adequate bone mineralization. Vitamin D, as calcitriol (1,25(OH)2D), not only increases intestinal calcium and phosphate absorption but also facilitates their renal reabsorption, leading to elevated serum calcium and phosphate levels. The interaction of 1,25(OH)2D with its receptor (VDR) increases the efficiency of intestinal absorption of calcium to 30–40% and phosphate to nearly 80%. Serum phosphate levels can also influence 1,25 (OH)2D and fibroblast growth factor 23 (FGF23) levels, i.e., higher phosphate concentrations suppress vitamin D activation and stimulate parathyroid hormone (PTH) release, while a high FGF23 serum level leads to reduced vitamin D synthesis. In the vitamin D-deficient state, the intestinal calcium absorption decreases and the secretion of PTH increases, which in turn causes the stimulation of 1,25(OH)2D production, resulting in excessive urinary phosphate loss. Maintenance of phosphate homeostasis is essential as hyperphosphatemia is a risk factor of cardiovascular calcification, chronic kidney diseases (CKD), and premature aging, while hypophosphatemia is usually associated with rickets and osteomalacia. This chapter elaborates on the possible interactions between vitamin D and phosphate in health and disease.
Visualization of the recovery process of defects in a cultured cell layer by chemical imaging sensor
(2016)
The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) in the sample. In this study, a novel cell assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the recovery of defects in a cell layer brought into proximity of the sensing surface. A reduced impedance at a defect formed artificially in a cell layer was successfully visualized in a photocurrent image. The cell layer was cultured over two weeks, during which the temporal change of the photocurrent distribution corresponding to the recovery of the defect was observed.
The chemical imaging sensor is a field-effect sensor which is able to visualize both the distribution of ions (in LAPS mode) and the distribution of impedance (in SPIM mode) inthe sample. In this study, a novel wound-healing assay is proposed, in which the chemical imaging sensor operated in SPIM mode is applied to monitor the defect of a cell layer brought into proximity of the sensing surface.A reduced impedance inside the defect, which was artificially formed ina cell layer, was successfully visualized in a photocurrent image.
Visual Virology
(2012)
Virgin passive colon biomechanics and a literature review of active contraction constitutive models
(2022)
The objective of this paper is to present our findings on the biomechanical aspects of the virgin passive anisotropic hyperelasticity of the porcine colon based on equibiaxial tensile experiments. Firstly, the characterization of the intestine tissues is discussed for a nearly incompressible hyperelastic fiber-reinforced Holzapfel–Gasser–Ogden constitutive model in virgin passive loading conditions. The stability of the evaluated material parameters is checked for the polyconvexity of the adopted strain energy function using positive eigenvalue constraints of the Hessian matrix with MATLAB. The constitutive material description of the intestine with two collagen fibers in the submucosal and muscular layer each has been implemented in the FORTRAN platform of the commercial finite element software LS-DYNA, and two equibiaxial tensile simulations are presented to validate the results with the optical strain images obtained from the experiments. Furthermore, this paper also reviews the existing models of the active smooth muscle cells, but these models have not been computationally studied here. The review part shows that the constitutive models originally developed for the active contraction of skeletal muscle based on Hill’s three-element model, Murphy’s four-state cross-bridge chemical kinetic model and Huxley’s sliding-filament hypothesis, which are mainly used for arteries, are appropriate for numerical contraction numerical analysis of the large intestine.
Es werden Effizienzbegriffe zum Vergleich von statistischen Tests basierend auf verschiedenen statistischen Experimenten eingeführt. Dabei handelt es sich um die schon aus dem Vergleich von statistischen Tests in je demselben Modell bekannten asymptotischen relativen Effizienzen wie die Hodges-Lehmann-Effizienz, die Bahadur-Effizienz und die Pitman-Effizienz sowie um Kriterien basierend auf Volumina von Konfidenzbereichen. Effizienzaussagen werden unter anderem für Likelihood-Quotienten-Tests und Waldsche Tests im Rahmen eines allgemeinen multivariaten parametrischen Modells erhalten. Statistische Tests zur Prüfung von Hypothesen über die relative Wirksamkeit zweier Experimente werden vorgeschlagen. Auf der Grundlage der erhaltenen Ergebnisse erfolgt ein Vergleich der Wirksamkeit von korrespondierenden Verfahren bei verbundener Stichprobenerhebung und unabhängiger Stichprobenerhebung. Die Rolle der Kovarianzmatrix bei verbundener Stichprobenerhebung wird insbesondere unter der Annahme, dass die zugrunde liegenden Verteilungen durch k-parametrische Exponentialfamilien modellierbar sind, herausgearbeitet. Verbindungen zu Effizienzbegriffen bei Punkt- und Konfidenzbereichsschätzverfahren werden aufgezeigt. Ausführlichere Untersuchungen betreffen die korrespondierenden Hotellingschen T²-Tests im multivariaten Normalverteilungsfall, die klassischen Homogenitatstests bei k × k-Kontingenztafeln und die Wilcoxon Tests in nichtparametrischen Lagealternativmodellen
Clearance of blood components and fluid drainage play a crucial role in subarachnoid hemorrhage (SAH) and post hemorrhagic hydrocephalus (PHH). With the involvement of interstitial fluid (ISF) and cerebrospinal fluid (CSF), two pathways for the clearance of fluid and solutes in the brain are proposed. Starting at the level of capillaries, flow of ISF follows along the basement membranes in the walls of cerebral arteries out of the parenchyma to drain into the lymphatics and CSF [1]–[3]. Conversely, it is shown that CSF enters the parenchyma between glial and pial basement membranes of penetrating arteries [4]–[6]. Nevertheless, the involved structures and the contribution of either flow pathway to fluid balance between the subarachnoid space and interstitial space remains controversial. Low frequency oscillations in vascular tone are referred to as vasomotion and corresponding vasomotion waves are modeled as the driving force for flow of ISF out of the parenchyma [7]. Retinal vessel analysis (RVA) allows non-invasive measurement of retinal vessel vasomotion with respect to diameter changes [8]. Thus, the aim of the study is to investigate vasomotion in RVA signals of SAH and PHH patients.
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.
The ClearPET™ project is proposed by working groups of the Crystal Clear Collaboration (CCC) to develop a 2nd generation high performance small animal positron emission tomograph (PET). High sensitivity and high spatial resolution is foreseen for the ClearPET™ camera by using a phoswich arrangement combining mixed lutetium yttrium aluminum perovskite (LuYAP:Ce) and lutetium oxyorthosilicate (LSO) scintillating crystals. Design optimizations for the first photomultiplier tube (PMT) based ClearPET camera are done with a Monte-Carlo simulation package implemented on GEANT3 (CERN, Geneva, Switzerland). A dual-head prototype has been built to test the frontend electronics and was used to validate the implementation of the GEANT3 simulation tool. Multiple simulations were performed following the experimental protocols to measure the intrinsic resolution and the sensitivity profile in axial and radial direction. Including a mean energy resolution of about 27.0% the simulated intrinsic resolution is about (1.41±0.11)mm compared to the measured of (1.48±0.06)mm. The simulated sensitivity profiles show a mean square deviation of 12.6% in axial direction and 3.6% in radial direction. Satisfactorily these results are representative for all designs and confirm the scanner geometry.
Validation of a novel method for detecting and stabilizing malfunctioning areas in fuel cell stacks
(2014)
In this paper a setup for detecting malfunctioning areas of MEAs in fuel cell stacks is described. Malfunctioning areas generate electric cross currents inside bipolar plates. To exploit this we suggest bipolar plates consisting not of two but of three layers. The third one is a highly conducting layer and segmented such that the cross currents move along the segments to the surface of the stack where they can be measured by an inductive sensor. With this information a realistic model can be used to detect the malfunctioning area. Furthermore the third layer will prevent any current inhomogeneity of a malfunctioning cell to spread to neighbouring cells in the stack. In this work the results of measurements in a realistic cell setup will be compared with the results obtained in simulation studies with the same configuration. The basis for the comparison is the reliable characterisation of the electrical properties of the cell components and the implication of these results into the simulation model. The experimental studies will also show the limits in the maximum number of segments, which can be used for a reliable detection of cross currents.
Using a cell-based gas biosensor for investigation of adverse effects of acetone vapors in vitro
(2013)
The present article describes a standard instrument for the continuous online determination of retinal vessel diameters, the commercially available retinal vessel analyzer. This report is intended to provide informed guidelines for measuring ocular blood flow with this system. The report describes the principles underlying the method and the instruments currently available, and discusses clinical protocol and the specific parameters measured by the system. Unresolved questions and the possible limitations of the technique are also discussed.
The integration of nanostructured films containing biomolecules and silicon-based technologies is a promising direction for reaching miniaturized biosensors that exhibit high sensitivity and selectivity. A challenge, however, is to avoid cross talk among sensing units in an array with multiple sensors located on a small area. In this letter, we describe an array of 16 sensing units of a light-addressable potentiometric sensor (LAPS), which was made with layer-by-layer (LbL) films of a poly(amidomine) dendrimer (PAMAM) and single-walled carbon nanotubes (SWNTs), coated with a layer of the enzyme penicillinase. A visual inspection of the data from constant-current measurements with liquid samples containing distinct concentrations of penicillin, glucose, or a buffer indicated a possible cross talk between units that contained penicillinase and those that did not. With the use of multidimensional data projection techniques, normally employed in information visualization methods, we managed to distinguish the results from the modified LAPS, even in cases where the units were adjacent to each other. Furthermore, the plots generated with the interactive document map (IDMAP) projection technique enabled the distinction of the different concentrations of penicillin, from 5 mmol L−1 down to 0.5 mmol L−1. Data visualization also confirmed the enhanced performance of the sensing units containing carbon nanotubes, consistent with the analysis of results for LAPS sensors. The use of visual analytics, as with projection methods, may be essential to handle a large amount of data generated in multiple sensor arrays to achieve high performance in miniaturized systems
On the model of musculocutaneous wound in rats, the effect of applicative sorption by carbonized rise shell (CRS) on the healing of festering wound was studied. It has been shown, that cytological changes end with rapid scar formation. The use of CRS at the period of severe purulent wound contributes to its favorable course, prevents the development of complications of the animals from sepsis.
This chapter shows that nanomaterials obtained by high-temperature carbonization of inexpensive plant raw material such as rice husk, grape seeds, and walnut shells can serve as a basis for the production of highly efficient microbial drugs, biodestructors, biosorbents, and biocatalysts, which are promising for the remediation of the ecosystem contaminated with heavy and radioactive metals, oil and oil products. A strong interest in engineering zymology is dictated by the necessity to address the issues of monitoring enzymatic processes, treatment, and diagnosis of a number of common human diseases, environmental pollution, quality control of pharmaceuticals and food. Nanomaterials obtained by high-temperature carbonization of cheap plant raw material such as-rice husks, grape seeds and walnut shells, can serve as a basis for creating of highly effective microbial preparations-biodestructors, biosorbents and biocatalysts, which are promising for the use of contaminated ecosystems, and for restoration of human intestine microecology.
Zusammenfassung: In der Orthopädie zählt der therapeutische Ultraschall als Mittel zur Prävention und Therapiebegleitung. Er hat mechanische, thermische und physiko-chemische Auswirkungen auf den menschlichen Körper. Um mehr Erkenntnisse über die thermischen Auswirkungen zu erlangen, wurden Versuche an einem Hydrogel-Phantom und an Probanden durchgeführt. Dabei entstand eine signifikante Erwärmung des Gewebes, welche beim Probandenversuch an der Oberfläche und beim Hydrogelversuch in der Tiefe gemessen wurde.
Summary: In orthopaedics, therapeutic ultrasound is a tool of prevention and therapy support. It has mechanical, thermal and physico-chemical effects on the human body. Tests with a hydrogel phantom and with human probands have been performed in order to obtain more knowledge about their thermal effects. Both tests measured temperature increases in cell tissue, on the surface with the human proband test and in depth with the hydrogel phantom test.
Unser Schlüssel zur Ewigkeit
(2015)
We investigate interaction networks that we derive from multivariate time series with methods frequently employed in diverse scientific fields such as biology, quantitative finance, physics, earth and climate sciences, and the neurosciences. Mimicking experimental situations, we generate time series with finite length and varying frequency content but from independent stochastic processes. Using the correlation coefficient and the maximum cross-correlation, we estimate interdependencies between these time series. With clustering coefficient and average shortest path length, we observe unweighted interaction networks, derived via thresholding the values of interdependence, to possess non-trivial topologies as compared to Erdös-Rényi networks, which would indicate small-world characteristics. These topologies reflect the mostly unavoidable finiteness of the data, which limits the reliability of typically used estimators of signal interdependence. We propose random networks that are tailored to the way interaction networks are derived from empirical data. Through an exemplary investigation of multichannel electroencephalographic recordings of epileptic seizures – known for their complex spatial and temporal dynamics – we show that such random networks help to distinguish network properties of interdependence structures related to seizure dynamics from those spuriously induced by the applied methods of analysis.
Unitary Operator
(2009)
This paper presents a numerical procedure for reliability analysis of thin plates and shells with respect to plastic collapse or to inadaptation. The procedure involves a deterministic shakedown analysis for each probabilistic iteration, which is based on the upper bound approach and the use of the exact Ilyushin yield surface. Probabilistic shakedown analysis deals with uncertainties originated from the loads, material strength and thickness of the shell. Based on a direct definition of the limit state function, the calculation of the failure probability may be efficiently solved by using the First and Second Order Reliability Methods (FORM and SORM). The problem of reliability of structural systems (series systems) is handled by the application of a special technique which permits to find all the design points corresponding to all the failure modes. Studies show, in this case, that it improves considerably the FORM and SORM results.