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We investigate an ultra-cold mixture of Bose gases interacting via spin-changing collisions by studying the dynamics of spin fluctuations. The experimental implementation employs $^{23}$Na and $^{7}$Li atoms, which are prepared out of equilibrium across a wide range of initial conditions. We identify three regimes in the dynamics of the system for different initial states: a long-lived metastable regime, an instability range with strong growth of fluctuations, and a fast relaxing regime approaching thermal equilibrium. Theoretical modelling of the data allows us to reconstruct effective potentials which characterize the different dynamical regimes of the system., 9 pages, 5 figures

Imposante Dachwerke, Holzbrücken oder jahrhundertealte Glockenstühle beeindrucken nicht nur Baufachleute. Sie für die Zukunft zu erhalten, ist allerdings eine immense Herausforderung. Welches Fachwissen dazu nötig ist, zeigen die Beispiele in diesem Buch. Die Autoren und Autorinnen, erfahrene Spezialisten der Bauwerkserhaltung, spannen einen weiten Bogen: vom Rohstoff Holz, den Transport- und Verarbeitungstechniken, der Erfassung, Dokumentation und der ingenieurtechnischen Analyse erhaltener Holzbauwerke über typische Schadensfälle bis hin zum sorgsamen Umgang mit dem Bestand. Bevor Erhaltungskonzepte diskutiert werden, ist es notwendig, ein Bauwerk in seinem historischen Kontext zu verstehen. Auch die oft komplexen Tragwerke und vorhandene Schäden müssen analysiert und denkmalverträgliche Nutzungen durchdacht werden. Schädlingsbefall oder Schadstoffe erfordern besondere Maßnahmen. Die Notwendigkeit der wiederkehrenden professionellen Bauwerksprüfung, Wartung und Pflege sind zu bedenken. Bei Modernisierungen sind heute besonders die Möglichkeiten nachträglicher Innendämmungen und Probleme bei der Anwendung der aktuell geltenden DIN-Normen und Bauvorschriften zu berücksichtigen. Aus dem Inhalt: Holz im historischen Steinbau Konstruktion und Tragverhalten historischer Dachtragwerke Konstruktion, Bewertung und Instandsetzung historischer Holzglockenstühle Vom Modell zum Bauwerk – historische Holzbrücken in der Schweiz Entwicklung und Geschichte der Holzachterbahn "Zollingerhalle oder Imitat?" Nachrechnung eines Holzgittertragwerks Voruntersuchung an Baudenkmälern hinsichtlich Holzschädlingsbefall und bzw. oder Holzschutzschutzmittelrückstände Erkenntnisse aus wiederkehrenden Bauwerksprüfungen von Kirchendächern Leitfaden zur Dokumentation von Schäden im Konstruktiven Holzbau Das Dacherwerk der St.-Aegidien-Kirche in Braunschweig aus dem Jahr 1514 – Bauforschung an einem bisher unbekannten aufgeständerten Kehlbalkendach Schadenfreie Innendämmung Restaurierung des mittelalterlichen Dachs am Kapitelhaus in Konstanz Die Dillinger Stadtpfarrkirche St. Peter – 400 Jahre Notsicherung Ein Notdach zwischen Denkmalwert und Einsturzgefahr

Bioresorbable nanofiber nonwovens with their fascinating properties provide a wide range of potential biomedical applications. Modification of the material enables the adjustment of mechanical and biological characteristics depending on the desired application. Due to the nanosized fiber network, post-production structuring is very challenging. Within this study, we use femtosecond laser technology for structuring permeable and resorbable electrospun poly-L-lactide (PLLA) membranes. We show that this post-production process can be used without disturbing the fiber network near the structured areas. Furthermore, the modification of the water permeability and mechanical characteristics due to the laser structuring was investigated. The results prove femtosecond laser technology to be a promising method for the adjustment of the membrane properties and which in consequence can help to optimize cell adhesion, enable revascularization and open up applications of nanofiber membranes in personalized medicine.

Mitral regurgitation (MR) is the second most frequent indication for heart valve surgery and catheter interventions. According to European and US-American guidelines, transcatheter mitral valve repair in general and transcatheter edge-to-edge repair (TEER) in particular may be considered as a treatment option for selected high-risk patients. However, the biomechanical impact of TEERdevices on the mitral valve (MV) has not yet been fully understood. To address this problem, a 3D-Fluid-Structure Interaction (FSI) framework utilizing non-linear Finite Element Analysis (FEA) for the MV apparatus and Smoothed Particle Hydrodynamics (SPH) for the pulsatile fluid flow was developed and validated against in vitro data. An artificial MV-model (MVM) with a prolapse in the A2-P2 region and a custom-made TEER device implanted in the A2-P2 region were used for the in vitro investigations. In accordance with ISO 5910, projected mitral orifice areas (PMOA), flow rates as well as atrial and ventricular pressures were measured under pulsatile flow conditions before and after TEER device implantation. For the FSI-model, the MVM geometry was reconstructed by means of microcomputed tomography in a quasi-stress-free configuration. Quasi-static tensile test data was utilized for the development of linear- and hyperelastic material models of the chordae tendineae and leaflets, respectively. The fluid flow was modelled assuming an incompressible, homogenous Newtonian behaviour. Time-varying in vitro transmitral pressure loading was applied as a boundary condition. In vitro investigations show that TEER device implantation in the A2-P2 region effectively reduces the regurgitation fraction (RF) from 55 % to 13 %. Moreover, the comparison of experimental and numerical data yields a deviation of 2.09 % for the RF and a deviation of 0.40 % and 6.47 % for the maximum and minimum PMOA, respectively. The developed FSI-framework is in good agreement with in vitro data and is therefore applicable for the characterization of the biomechanical impact of different TEER devices under pulsatile flow conditions.

ZusammenfassungDie vorliegende Leitlinie umfasst ein aktualisiertes Konzept der Behandlung und Prävention von erwachsenen Patienten mit ambulant erworbener Pneumonie und löst die bisherige Leitlinie aus dem Jahre 2016 ab.Sie wurde entsprechend den Maßgaben zur Methodologie einer S3-Leitlinie erarbeitet und verabschiedet. Hierzu gehören eine systematische Literaturrecherche und -bewertung, die strukturierte Diskussion der aus der Literatur begründbaren Empfehlungen sowie eine Offenlegung und Bewertung möglicher Interessenskonflikte.Die Leitlinie zeichnet sich aus durch eine Zentrierung auf definierte klinische Situationen, eine aktualisierte Maßgabe der Schweregradbestimmung sowie Empfehlungen zu einer individualisierten Auswahl der initialen antimikrobiellen Therapie.Die Empfehlungen zielen gleichzeitig auf eine strukturierte Risikoevaluation als auch auf eine frühzeitige Bestimmung des Therapieziels, um einerseits bei kurativem Therapieziel die Letalität der Erkrankung zu reduzieren, andererseits bei palliativem Therapieziel eine palliative Therapie zu eröffnen.

Using dual theories embedded into a larger unphysical Hilbert space along entanglement cuts, we study the Entanglement Structure of $\mathbf{Z}_2$ lattice gauge theory in $(2+1)$ spacetime dimensions. We demonstrate Li and Haldane's conjecture, and show consistency of the Entanglement Hamiltonian with the Bisognano-Wichmann theorem. Studying non-equilibrium dynamics after a quench, we provide an extensive description of thermalization in $\mathbf{Z}_2$ gauge theory which proceeds in a characteristic sequence: Maximization of the Schmidt rank and spreading of level repulsion at early times, self-similar evolution with scaling coefficients $\alpha = 0.8 \pm 0.2$ and $ \beta = 0.0 \pm 0.1$ at intermediate times, and finally thermal saturation of the von Neumann entropy., Comment: Journal version: additional numerical finite volume studies included; improved error estimates; references updated; 11 pages, 8 figures

Mitral regurgitation (MR) is the most prevalent valvulopathy in the USA and the second most prevalent valvulopathy in Europe. Despite excellent clinical results of surgical mitral valve repair (SMVR), transcatheter-based mitral valve repair (MVR) procedures emerged as a feasible treatment option for surgically inoperable or high-risk patients suffering from clinically relevant MR. The current study investigates the impact of device-induced coaptationwidth on the hydrodynamic performance of insufficient mitral valves (MV) during left ventricular (LV) systole. A non-calcified, pathological MV model (MVM) featuring a D-shaped MV annulus with an area of 7.6 cm2 and a flail gap in the A2-P2 region was employed in an experimental setup. Pressure gradient-volumetric flow rate (Δp-Q) relations were investigated for steady-state backward flow with transvalvular pressure gradients ranging from (0.75 ≤ Δp ≤ 177.36) mmHg. Glycerol-water mixture (36 % (v/v) glycerol in water) at 37 °C with a density of (1 098.2 ± 1.3) kg·m-3 and a dynamic viscosity of 3.5 mPa∙s was used as circulatory fluid. In order to determine the impact of the width of transcatheter MVR devices during LV-systole Δp-Q relations were investigated for three MVM-configurations: (i) MVM without MVR device, (ii) MVM with one MVR device and (iii) MVM with two MVR devices implanted in the A2-P2 region. The MVR devices were manufactured from steel sheets with a thickness of 0.2 mm and feature arm lengths of 9.0 mm and a width of 5.0 mm. The conducted investigations show that the implantation of MVR devices in the A2-P2 region prevents the manifestation of an A2-P2 flail gap and thereby effectively reduces the retrograde blood flow during the LV-systole by 13 % with one MVR device and 27 % with two MVR devices implanted. Thus, the application of two MVR devices with a combined device-induced width of 10 mm results in a better MR reduction than the implantation of one MVR device with a device-induced width of 5 mm.

Nanofiber nonwoven membranes produced by electrospinning provide the possibility to adjust mechanical material parameters as well as simultaneously the biologically relevant properties - a fundamental aspect in developing new implants and medical devices. Wettability and permeability are also of great importance, as they have a decisive influence on the release of drugs, cell attachment, degradability and finally the nutrient supply of the surrounding tissue. Within this work the wettability and permeability of several electrospun poly-L-lactide nonwovens, including different additives, were investigated and a correlation to membrane morphology was found. A potential modification of the permeability by the fluid viscosity was also investigated. The results form a fundamental building block in the development of permeable biodegradable implants and medical devices.

Experience of disease, relationship and sexuality in patients with COPDObjectives: We aimed to determine the impacts of chronic obstructive pulmonary disease (COPD) on the patient's relationship and sexuality. Methods: In a multicentric study 105, 52 of them female, non-selected COPD patients who were married or in a partnership were interviewed about their partnership and sexuality. Results: Average age was 64.1 ± 9.2 years. Patients with a more severe COPD had a lower Self-Illness-Separation (SIS), i. e. they reveal significantly higher burden of suffering. Life satisfaction and satisfaction with partnership, sexuality and sexual intercourse has decreased significantly since the diagnosis (p < 0.05). Desire and frequency to be sexually active have also decreased (p < 0.001). 61 % of the respondents felt increasingly dependent from their partner. Conclusion: The results underline that patients have a stage-dependent emotional distance to their illness, the partnership develops in direction of dependency, and sexuality deteriorates with increasing severity of the COPD. The PRISM test proved to be a great way to illustrate this development and to start a conversation with the patients about it. COPD patients and their partners should be referred to the potential impact of the disease on their partnership and sexuality and should be supported in their potential solutions considering gender-specific aspects.

Although the development of the transcatheter aortic valve (TAV) has saved many lives of inoperable patients and has a very good clinical outcome, concerns about valve thrombosis are increasing. Due to the potential risk of late clinically relevant events, the US Food and Drug Administration (FDA) suggests a careful systematic investigation of thrombosis and reduced leaflet motion related to hemodynamic changes induced by TAV implantation. Furthermore, recently published position papers of the ISO working group address numerical and experimental flow field assessment of TAV. In particular, pathologically high shear rates and a reduced washout of the sinuses may increase the risk of valve thrombosis and should therefore be investigated. By means of fluid-structure interaction (FSI) as a powerful in silico tool, the transient flow field in an aortic valve was analyzed. A linear elastic behavior was assumed for leaflet material properties (Young modulus: 10 MPa, Poisson ratio: 0.46 and leaflet material density: 1000 kg/m3) and blood was specified as a homogeneous, Newtonian and incompressible fluid (fluid density: 1060 kg/m3 and a dynamic viscosity: 0.0035 Pa s). In this numerical study we present a Eulerian approach, which is based on transport equation of the residence time (RT) as a passively transported scalar. It can be clearly seen that the RT is significantly higher in the sinus referred to the main flow. At time step t = 0.25 s, the average residence time in the main flow is RTavg ≈ 0.05 s, whereas RT ≈ 0.25 s in the sinus. In particular, RT is a valuable hemodynamic metric to quantify the washout of the sinus in order to evaluate the thrombogenic potential of TAV devices. Further studies will concentrate on particle image velocimetry measurements for validation purposes. In particular the velocity in the sinus and therefore the washout is one important hemodynamic key feature that has to be improved for future TAV designs.

This thesis examines the ways in which fashion designers think about themselves, the design process, and the fashion industry. Recent interest in design thinking has brought decision making to the forefront in an effort to resolve conflicts between creative individuals and managers during the design process. Within the fashion design literature there are studies of processes in large fashion manufacturing enterprises but very little has focused on small-scale fashion design entrepreneurs. In this inductive, qualitative study, I use grounded theory as the methodology in the analysis of semi-structured interviews of twelve Canadian fashion design entrepreneurs. The findings explore their perceptions of their identity as designers, their perceptions of design process, and their relationship to their business. This research has developed the concept of “artisanal fashion design” as a distinct subset of design for further study and for consideration by organizations, the fashion industry, and educators.

Background The infectious coronavirus disease 2019 (COVID-19) pandemic is an ongoing global healthcare challenge. Up to one-third of hospitalised patients develop severe pulmonary complications and acute respiratory distress syndrome. Pulmonary outcomes following COVID-19 are unknown. Methods The Swiss COVID-19 lung study is a multicentre prospective cohort investigating pulmonary sequelae of COVID-19. We report on initial follow-up 4 months after mild/moderate or severe/critical COVID-19 according to the World Health Organization severity classification. Results 113 COVID-19 survivors were included (mild/moderate n=47, severe/critical n=66). We confirmed several comorbidities as risk factors for severe/critical disease. Severe/critical disease was associated with impaired pulmonary function, i.e. diffusing capacity of the lung for carbon monoxide (DLCO) % predicted, reduced 6-min walk distance (6MWD) and exercise-induced oxygen desaturation. After adjustment for potential confounding by age, sex and body mass index (BMI), patients after severe/critical COVID-19 had a DLCO 20.9% pred (95% CI 12.4–29.4% pred, p=0.01) lower at follow-up. DLCO % pred was the strongest independent factor associated with previous severe/critical disease when age, sex, BMI, 6MWD and minimal peripheral oxygen saturation at exercise were included in the multivariable model (adjusted odds ratio per 10% predicted 0.59, 95% CI 0. 37–0.87; p=0.01). Mosaic hypoattenuation on chest computed tomography at follow-up was significantly associated with previous severe/critical COVID-19 including adjustment for age and sex (adjusted OR 11.7, 95% CI 1.7–239; p=0.03). Conclusions 4 months after severe acute respiratory syndrome coronavirus 2 infection, severe/critical COVID-19 was associated with significant functional and radiological abnormalities, potentially due to small-airway and lung parenchymal disease. A systematic follow-up for survivors needs to be evaluated to optimise care for patients recovering from COVID-19., COVID-19 pulmonary sequelae are unknown. The Swiss COVID-19 lung study reports on initial follow-up findings. Severe or critical COVID-19 was associated with significant functional impairment and radiological abnormalities after 4 months. https://bit.ly/34sNVvi

Background Sleep-disordered breathing (SDB) is highly prevalent in acute ischaemic stroke and is associated with worse functional outcome and increased risk of recurrence. Recent meta-analyses suggest the possibility of beneficial effects of nocturnal ventilatory treatments (continuous positive airway pressure (CPAP) or adaptive servo-ventilation (ASV)) in stroke patients with SDB. The evidence for a favourable effect of early SDB treatment in acute stroke patients remains, however, uncertain. Methods eSATIS is an open-label, multicentre (6 centres in 4 countries), interventional, randomized controlled trial in patients with acute ischaemic stroke and significant SDB. Primary outcome of the study is the impact of immediate SDB treatment with non-invasive ASV on infarct progression measured with magnetic resonance imaging in the first 3 months after stroke. Secondary outcomes are the effects of immediate SDB treatment vs non-treatment on clinical outcome (independence in daily functioning, new cardio-/cerebrovascular events including death, cognition) and physiological parameters (blood pressure, endothelial functioning/arterial stiffness). After respiratory polygraphy in the first night after stroke, patients are classified as having significant SDB (apnoea-hypopnoea index (AHI) > 20/h) or no SDB (AHI Discussion The trial will give information on the feasibility and efficacy of ASV treatment in patients with acute stroke and SDB and allows assessing the impact of SDB on stroke outcome. Diagnosing and treating SDB during the acute phase of stroke is not yet current medical practice. Evidence in favour of ASV treatment from a randomized multicentre trial may lead to a change in stroke care and to improved outcomes. Trial registration ClinicalTrials.gov NCT02554487, retrospectively registered on 16 September 2015 (actual study start date, 13 August 2015), and www.kofam.ch (SNCTP000001521).

We propose a scalable analog quantum simulator for quantum electrodynamics (QED) in two spatial dimensions. The setup for the U(1) lattice gauge field theory employs inter-species spin-changing collisions in an ultra-cold atomic mixture trapped in an optical lattice. Building on the previous one-dimensional implementation scheme of Ref. [1] we engineer spatial plaquette terms for magnetic fields, thus solving a major obstacle towards experimental realizations of realistic gauge theories in higher dimensions. We apply our approach to pure gauge theory and discuss how the phenomenon of confinement of electric charges can be described by the quantum simulator., 5 pages, 3 figures

The state-of-the-art non-invasive measurement of peripheral oxygen saturation (SpO2) during sleep is mainly based on pulse oximetry at the fingertip. Although this approach is noninvasive, it can still be obtrusive and cumbersome to apply, in particular for ambulatory monitoring over several nights.We developed a wrist-worn reflectance pulse oximetry device which can be embedded in a watch, making it less obtrusive and easy to apply. This device was tested in an ongoing clinical study on 57 subjects (33 patients and 24 healthy volunteers) undergoing a full overnight polysomnography recording. The accuracy was evaluated against state-of-the-art fingertip SpO2 measurements.In the 54 subjects available for analysis we obtained an SpO2 accuracy (ARMS) of 3.4 % when automatically rejecting 17.7 % of signals due to low quality. When further excluding measurements suffering from insufficient contact of the watch with the skin an ARMS of 2.7 % was obtained while rejecting a total of 23.2 % measurements. These accuracies comply with the ISO standard and the FDA guidance for pulse oximeters.The present results are promising and pave the way for unobtrusive and continuous monitoring of SpO2 to screen for sleep disordered breathing. Nonetheless, contact pressure and venous blood have shown to adversely affect the SpO2 estimation and remain a challenge for wrist-based reflectance pulse oximetry.

Sleep-disordered breathing (SDB) is frequent in patients with acute stroke. Little is known, however about the evolution of SDB after stroke. Most of our knowledge stems from smaller cohort studies applying limited cardiopulmonary sleep recordings or from cross-sectional data collected in different populations. This study aims to determine prevalence, type and intra-individual evolution of SDB based on full-night polysomnography (PSG) in acute stroke and 3 months thereafter. Furthermore, we aimed to identify predictors of SDB in the acute and chronic phase and to evaluate associations between SDB and functional outcome at 3 months (M3). A total of 166 patients with acute cerebrovascular events were evaluated by full PSG at baseline and 105 again at M3. The baseline prevalence of SDB (apnoea–hypopnoea index (AHI)>5·h−1) was 80.5% and 25.4% of the patients had severe SDB (AHI>30·h−1). Obstructive sleep apnoea was more prevalent than central sleep apnoea (83.8% versus 13%). Mean±SD AHI was 21.4±17.6·h−1and decreased significantly at M3 (18±16.4·h−1; p=0.018). At M3, 91% of all patients with baseline SDB still had an AHI>5·h−1 and in 68.1% the predominant type of SDB remained unchanged (78.9% in obstructive sleep apnoea and 44.4% in central sleep apnoea). The only predictors of SDB at baseline were higher age and body mass index and in the chronic phase additionally baseline AHI. Baseline AHI was associated with functional outcome (modified Rankin score >3) at M3. The high prevalence of SDB in acute stroke, its persistence after 3 months, and the association with functional outcome supports the recommendation for a rapid SDB screening in stroke patients., The high prevalence of SDB in acute stroke, its persistence after 3 months and its association with functional outcome support the recommendation for rapid SDB screening in stroke patients https://bit.ly/3bFWqV7

Quantum fluctuations lead to an anomalous violation of parity symmetry in quantum electrodynamics for an even number of spatial dimensions. While the leading parity-odd electric current vanishes in vacuum, we uncover a non-cancellation of the anomaly for strong electric fields with distinct macroscopic signatures. We perform real-time lattice simulations with fully dynamical gauge fields and Wilson fermions in $2+1$ space-time dimensions. In the static field limit, relevant at early times, we solve the problem analytically. Our results point out the fundamental role of quantum anomalies for strong-field phenomena, relevant for a wide range of condensed matter and high-energy applications, but also for the next generation of gauge theory quantum simulators., 6 pages, 4 figures

The modern description of elementary particles, as formulated in the standard model of particle physics, is built on gauge theories

An established therapy for aortic valve stenosis and insufficiency is the transcatheter aortic valve replacement. By means of numerical simulation the valve dynamics can be investigated to improve the valve prostheses performance. This study examines the influence of the hemodynamic properties on the valve dynamics utilizing fluidstructure interaction (FSI) compared with results of finiteelement analysis (FEA). FEA and FSI were conducted using a previously published aortic valve model combined with a new developed model of the aortic root. Boundary conditions for a physiological pressurization were based on measurements of ventricular and aortic pressure from in vitro hydrodynamic studies of a commercially available heart valve prosthesis using a pulse duplicator system. A linear elastic behavior was assumed for leaflet material properties and blood was specified as a homogeneous, Newtonian incompressible fluid. The type of fluid domain discretization can be described with an arbitrary Lagrangian-Eulerian formulation. Comparison of significant points of time and the leaflet opening area were used to investigate the valve opening behavior of both analyses. Numerical results show that total valve opening modelled by FEA is faster compared to FSI by a factor of 5. In conclusion the inertia of the fluid, which surrounds the valve leaflets, has an important influence on leaflet deformation. Therefore, fluid dynamics should not be neglected in numerical analysis of heart valve prostheses.

In tissue engineering and regenerative medicine mesenchymal stem cells (MSC) are widely used to replace and restore the function of dysfunctional or missing tissue. Recent studies have shown significant enhancements of the in vivo healing process following dentofacial bone augmentation procedures employing stem cell-loaded xenografts. We conducted experimental and numerical investigations in perfusion flow bioreactor-xenograft-systems to identify flow conditions as well as bioreactor design features that allow for homogeneous MSC-distribution in Geistlich Bio- Oss Block xenografts. Pressure gradient - velocity characteristics and flow distributions were investigated experimentally and numerically for two bioreactor designs at steady-state flow conditions with Reynolds numbers (Re) ranging from 0.01 ≤ Re ≤ 0.32. Distilled water at 20°C with a dynamic viscosity of 1.002 mPa∙s and a density of 998 kg/m3 was used. The geometry of the xenograft utilized in three-dimensional computational fluid dynamics (CFD) simulation was obtained by means of micro-computed tomography (μCT) at an isotropic spatial resolution of 9.5 μm. The permeability values calculated from the experimental data are in good accordance with the numerical results. The investigations showed that the increase of the inflow- and outflow-area diameter, as well as the decrease of the volumetric flow rate, result in a decreasing heterogeneity of the flow distribution within the xenograft. The calculated wall shear stress rates in the three-dimensional (3D) scaffold range from 1∙10-12Pa ≤ τ ≤ 0.2 Pa. Experimentally validated CFD simulations introduced in this study provide an applicable tool to assess optimal flow conditions for homogeneous MSC distribution in bioreactor-xenograft-systems.

Standardized methods and measures are ubiquitous in biomedical engineering and a key factor for the successful development and certification of novel biomaterials, implants or other medical devices. Hence, the development of standardized measurement techniques, which can be applied to nearly every material and device is of crucial importance. Within the current work, we introduce a method to evaluate the water permeability according to ISO/FDIS 7198. The setup was designed to determine the volumetric flow through a test sample for a given hydraulic pressure. One key feature is the effortless replacement of the chamber containing the test sample. The measurement technique can thus be applied to a variety of materials and medical devices. To demonstrate the functionality of the setup we fabricated nanofiber membranes using the process of electrospinning. Nonwovens with comparable thickness and varying morphology were analyzed with regard to water permeability. In particular the different fiber diameters as well as the modified inter-fiber distances result in large deviations of the water permeability. Furthermore, there are hints for a rearrangement of the nanofibers due to the applied hydraulic pressure. The developed measurement technique provides a powerful tool for the standardized quantification of the water permeability and can be applied to a variety of biomaterials and medical devices.

For the treatment of severe symptomatic aortic valve stenosis, minimally invasive heart valve prostheses have more recently become the lifesaving solution for elderly patients with high operational risk and thus, are often implanted in patients with challenging aortic root configuration. A correct prosthesis deployment and stent adaption to the target region is essential to ensure optimal leaflet performance and long-term prosthesis function. The objective of this study was the development of a suitable in silico setup for structural numerical simulation of a transcatheter aortic valve (TAV) in different cases of clinical relevance. A transcatheter valve prosthesis comprising an unpressurized trileaflet heart valve and an adapted stent configuration was designed. An aortic root (AR) model was developed, based on microcomputed tomography of a native healthy specimen. Using the finite-element analysis (FEA), various loading cases including prosthesis biomechanics with valve opening and closing under physiological pressure ratios throughout a cardiac cycle, prosthesis crimping as well as crimping and release into the developed AR model were simulated. Hyperelastic constitutive law for polymeric leaflet material and superelasticity of shape memory alloys for the self-expanding Nitinol stent structure were implemented into the FEA setup. Calculated performance of the valve including the stent structure demonstrated enhanced leaflet opening and closing as a result of stent deformation and redirected loading. Crimping and subsequent release into the AR model as well as the stent adaption to the target region after expansion proved the suitability of the TAV design for percutaneous application. FEA represented a useful tool for numerical simulation of an entire minimally invasive heart valve prosthesis in relevant clinical scenarios.

Compartmentalisation of the respiratory tract microbiota in patients with different chronic obstructive pulmonary disease (COPD) severity degrees needs to be systematically investigated. In addition, it is unknown if the inflammatory and emphysematous milieux in patients with COPD are associated with changes in the respiratory tract microbiota and host macrophage gene expression. We performed a cross-sectional study to compare non-COPD controls (n=10) to COPD patients (n=32) with different disease severity degrees. Samples (n=187) were obtained from different sites of the upper and lower respiratory tract. Microbiota analyses were performed by 16S ribosomal RNA gene sequencing and host gene expression analyses by quantitative real-time PCR of distinct markers of bronchoalveolar lavage cells. Overall, the microbial communities of severe COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade 3/4) patients clustered significantly differently to controls and less severe COPD (GOLD 1/2) patients (permutational multivariate ANOVA (MANOVA), p=0.001). However, we could not detect significant associations between the different sampling sites in the lower airways. In addition, the chosen set of host gene expression markers significantly separated COPD GOLD 3/4 patients, and we found correlations between the composition of the microbiota and the host data. In conclusion, this study demonstrates associations between host gene expression and microbiota profiles that may influence the course of COPD., Associations of the host immune response and a disordered microbiota in patients with different COPD severity degrees http://ow.ly/h2mW30k9Nua

In recent years, a progressive interest in the implementation of wireless access to cardiovascular implants has been established. This manifests in new devices, such as arterial pressure sensors, or additional functionalities added to established implants like stents. However, common stent designs, possessing highly optimized mechanical properties, often consist of cylindrically arranged struts with connections in-between which can be considered as short-circuited inductive coils. As a consequence, the small inductance raises the resonance frequency, which may decrease the in vivo performance of the wireless connection between the stent and the external readout device. Thus, new designs were developed to overcome this limitation, for example by avoiding the short-circuit due to a helical arrangement of the struts. Within this work we compare the performance of a common stent design and a helical design by means of numerical simulations. We are using two designs which only differ in the arrangement of the struts. The electromagnetic and mechanical properties are investigated using a finitedifference time-domain algorithm and finite element method, respectively. We will show that a common stent design exhibits resonance frequencies in the gigahertz regime, much higher than the frequencies of comparable helical designs. Furthermore, we compare the mechanical performance of the two designs and reveal individual distinctions in the radial stiffness, bending stiffness, and the von Mises stress.

Mitral regurgitation (MR) occurs with a prevalence of approximately 10 % in patients aged 75 years or older and therefore is one of the most frequent indications for heart valve surgery. During the last decade surgical mitral valve repair (MVR) procedures emerged as the gold standard for the treatment of clinically relevant MR. However, for surgically inoperable or high-risk patients transcatheter-based MVR devices present a valuable treatment option. Within the current study, we developed an experimental setup to investigate the hydrodynamic performance of transcatheterbased MVR devices in vitro. The bicuspid mitral valve (MV) model employed in the experimental setup features a D-shaped MV annulus with d1 = 26.30 mm, d2= 30.05 mm and chordae tendineae with a length of l1= 25 mm attached to two papillary muscle structures. Pressure gradient - volumetric flow rate (Δp-Q) relations were investigated for steady state backward flow with transvalvular pressure gradients ranging from 0.75 mmHg ≤ Δp ≤ 103.13 mmHg. Deionized water at 37 °C with a dynamic viscosity of 1.002 mPa∙s and a density of 998 kg/m3 was used. A test-chamber consisting of a press-fit MV holder and cylindrical in- and outflow tracts were developed. Different designs for the exchangeable press-fit MV holder were manufactured using additive manufacturing technologies providing an optimal fitting for variable MV sizes and pathologies. In- and outflow tracts featuring a diameter of d = 50 mm and a height of h = 60 mm were made from transparent polymethylmethacrylate to allow for easy optical access during measurements. The experimentally investigated Δp-Q relation yields a quadratic correlation for the open MV and a linear correlation for the closed MV. A transvalvular closing pressure of (4.94 ± 0.04) mmHg was measured for the MV model.

Nasal high-flow oxygen therapy (HFOT) is a novel treatment option for patients suffering from acute or chronic respiratory failure. Aim of our study was to compare safety and efficacy of HFOT with those of conventional oxygen treatment (COT) in normo- and hypercapnic COPD patients. A single cohort of 77 clinically stable hypoxemic patients with an indication for long-term oxygen treatment (LTOT) with or without hypercapnia successively received COT and HFOT for 60 min each, including oxygen adaption and separated by a 30 min washout phase. HFOT was well-tolerated in all patients. A significant decrease in PaCO2 was observed during oxygen adaption of HFOT, and increased PaO2 coincided with significantly increased SpO2 and decreased AaDO2 during both treatment phases. Even at a flow rate of 15 L/min, oxygen requirement delivered as air mixture by HFOT tended to be lower than that of COT (2.2 L/min). Not only was no increase in static or dynamic lung volumes observed during HFOT, but even was a significant reduction of residual lung volume measured in 36 patients (28%). Thus, short-term use of HFOT is safe in both normocapnic and hypercapnic COPD patients. Lower oxygen levels were effective in correcting hypoxemic respiratory failure and reducing hypercapnia, leading to a reduced amount of oxygen consumption. Long-term studies are needed to assess safety, tolerability, and clinical efficacy of HFOT. ClinicalTrials.gov NCT01686893 13.09.2012 retrospectively registered (STIT-1) and NCT01693146 14.09.2012 retrospectively registered (STIT-2). Studies were approved by the local ethics committee (Ethikkommission der Medizinischen Universitat Innsbruck, Studienkennzahl UN3547, Sitzungsnummer 274/4.19).

In dentofacial surgery, augmentation procedures employing xenografts have become a reliable treatment. Recent studies, however, have shown significant enhance-ments of the in vivo bone tissue augmentation using mesenchymal stem cells loaded into bone grafts. We conducted experimental and numerical investigations in flow perfusion systems to determine flow conditions which allow for homogenous stem cell distribution in BioOss Block (Geistlich Pharma AG, Switzerland) xenografts. Pressure gradient-velocity characteristics and flow distributions were investigated experimentally and numerically at steady state flow conditions with Reynolds numbers (Re) ranging from 0.01 ≤ Re ≤ 0.40. Distilled water at 20°C with a dynamic viscosity of 1.002 mPa.s and a density of 998 kg/m3 was used. The geometry utilized in three-dimensional computa-tional fluid dynamics (CFD) simulation was obtained by means of micro-computed tomography (μCT). Results of CFD analysis are in good accordance with experimental data. The comparison of the pressure gradient-velocity characteris-tics for experimental and numerical data yields a relative error of 3.6%. According to Darcy’s law for creeping fluid flow the experimentally determined permeability is 2.55.10-9 m2. Moreover, numerical flow distribution analysis shows an increasingly heterogenic streamline distribution for increasing Reynolds numbers. Experimentally validated CFD simulations introduced in this study provide a tool to assess optimal flow conditions for a homogenous stem cell distribution in perfusion flow systems.

Assessment of hydrodynamic performance of transcatheter aortic valve prostheses (TAVP) in vitro is es-sentially in the fields of development and approval of novel implants. For the prediction of clinical performance, in vitro testing of TAVP allows for benchmarking of different devic-es, likewise. In addition to the implant itself, also the testing environment has a crucial influence on leaflet dynamics and quantitative test results like effective orifice area (EOA) or aortic regurgitation. Therefore, within the current study we developed simpli-fied physiological and pathophysiological vessel models of the aortic root as a tool for in vitro hydrodynamic testing of TAVP in idealized and worst case conditions. We used 3D printing and silicone cast molding for manufacturing of aortic root models with variable degree of stenosis. Design of aortic roots with normal, mild and severe stenosis was developed according to Reul et al. For manufacturing of tripartite cast-ing molds, a 3D printer was used. Both outer mold parts and the mold core were manufactured from polylactide filament and water soluble polyvinylalcohol filament, respectively. In vitro hydrodynamic performance testing of an exemplary commercially available TAVP implanted in different aortic root models was conducted according to DIN EN ISO 5840-3:2013, using a pulse duplicator system. Manufactured aortic root models were highly transparent, dimensionally stable and therefore suitable for hydrodynamic testing of TAVP. Both, EOA and regurgitant fraction in-creased with increasing degree of stenosis from 1.6 ± 0.1 cm2 to 1.8 ± 0.1 cm2 and 8.6 ± 6.5% to 20.2 ± 4.2% (n = 30 cy-cles), respectively. We successfully developed a testing environment ena-bling sophisticated evaluation of hydrodynamic performance of TAVR in pathophysiological worst case conditions.

Low-fidelity, simulation-based psychomotor skills training is a valuable first step in the educational approach to mastering complex procedural skills. We developed a cost-effective bronchial tree simulator based on a human thorax computed tomography scan using rapid-prototyping (3D-print) technology. This randomised, single-blind study evaluated how realistic our 3D-printed simulator would mimic human anatomy compared with commercially available bronchial tree simulators (Laerdal® Airway Management Trainer with Bronchial Tree and AirSim Advance Bronchi, Stavanger, Norway). Thirty experienced anaesthetists and respiratory physicians used a fibreoptic bronchoscope to rate each simulator on a visual analogue scale (VAS) (0 mm = completely unrealistic anatomy, 100 mm = indistinguishable from real patient) for: localisation of the right upper lobe bronchial lumen; placement of a bronchial blocker in the left main bronchus; aspiration of fluid from the right lower lobe; and overall realism. The 3D-printed simulator was rated most realistic for the localisation of the right upper lobe bronchial lumen (p = 0.002), but no differences were found in placement of a bronchial blocker or for aspiration of fluid (p = 0.792 and p = 0.057) compared with using the commercially available simulators. Overall, the 3D-printed simulator was rated most realistic (p = 0.021). Given the substantially lower costs for the 3D-printed simulator (£85 (€100/US$110) compared with > ~ £2000 (€2350/US$2590) for the commercially available simulators), our 3D-printed simulator provides an inexpensive alternative for learning bronchoscopy skills, and offers the possibility of practising procedures on patient-specific models before attempting them in clinical practice.

Zusammenfassung Zielsetzung In den letzten Jahren konnte eine Steigerung der Anzahl privater Krankenhäuser und Betten festgestellt werden. Die Probleme der Investitionsfinanzierung deutscher Krankenhäuser in Kombination mit verstärkenden Faktoren wie der Einführung der DRGs, aber auch die Erwartung einer höheren Effizienz nach der Privatisierung einer Klinik können als Hauptgründe bei Privatisierungsentscheidungen genannt werden. Es soll untersucht werden, wie ehemalige öffentliche Krankenhausträger den Erfolg der Privatisierung einschätzen. Methodik Alle 99 identifizierten ehemaligen öffentlichen Träger, die ihr Krankenhaus in den Jahren 2003–2013 an einen privaten Eigentümer verkauft hatten, wurden hinsichtlich ihrer Einschätzung von Zielen sowie Befürchtungen vor und nach der Privatisierung anonym und schriftlich befragt. Ergebnisse und Schlussfolgerung Zusammenfassend lässt sich feststellen, dass bei einer ausreichenden Finanzierung der Krankenhäuser aus Krankenkassenbeiträgen (Betriebsmittel) und Ländermittel (Investitionskosten) der Privatisierungsdruck rapide sinken würde. Wenn jedoch privatisiert wurde, hatte dies aus Sicht der ehemaligen Träger weder einen negativen Einfluss auf die medizinische Versorgung in der Region, noch auf die Qualität der medizinischen Behandlung und auf den Umgang mit den Mitarbeitern. Die Einschätzungen der ehemaligen Träger weisen eine statistisch überprüfte Übereinstimmung auf. Die mit einer Privatisierung verbundenen Erwartungen und Ziele werden prinzipiell als erfüllt wahrgenommen.

This study addressed the evolution of microstructure across some duplex stainless steel joints welded by laser beam without and with applying additional materials. The chemical composition and the thickness of the parent material modify the welded joints profile also. Similar technological parameter results different macrostructure and ferrite content at different type of additional material. Pitting corrosion resistance were also studied.