81 research outputs found

    In-vitro und in-vivo Untersuchungen zur Nutzbarkeit des QuickOpt Verfahrens zur Individualisierung des AV-Delays

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    Die Individualisierung und Optimierung (Opt) des AV-Delays (AVD) sind in der kardialen Resynchronisationstherapie entscheidend. In-vitro-Untersuchung des QuickOpt-Algorithmus zur AVDOpt wurden am Herzrhythmusmodell durchgeführt und in-vivo mit echokardiographischer (Echo) AVDOpt (21 Pat.) verglichen. In-vitro betrug die Messgenauigkeit ±8 ms, Sensing/Herzfrequenz sind ohne AVD Einfluss, es zeigte sich eine signifikante Abhängigkeit des QuickOpt-AVD von der rechtsatrialen Amplitude. In-vivo war das QuickOpt-AVD vs. Echo-AVDOpt (ms) 41 ± 25/18 ± 24 zu lang, die Sensekompensation 23ms zu kurz

    Detection of time-, frequency- and direction-resolved communication within brain networks

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    This work was in part supported by a grant from the Macdonald Trust to BP and BS, and by a grant from the Alzheimer Society (AS-PG-14-039) to BP and GR.Peer reviewedPublisher PD

    Die Bildungsbiografie in der Blockchain - das Vorhaben MyEduLife

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    Um Innovationen für die berufliche Weiterbildung anzustoßen und einen Beitrag zur Optimierung eines digitalen und sicheren Bildungsraums zu leisten, hat das Bundesinstitut für Berufliche Bildung (BIBB) im Auftrag des Bundesministeriums für Bildung und Forschung (BMBF) einen Wettbewerb ins Leben gerufen. In diesem sollen Bedarfe der Nationalen Weiterbildungsstrategie aufgegriffen und eine Kohärenz im digitalen Weiterbildungsraum geschaffen werden, durch Verbesserung und Vernetzung von Weiterbildungsplattformen und Erhöhung von Weiterbildungsbeteiligung. Das im Rahmen dieses Wettbewerbs geförderte Projekt „MyEduLife“ adressiert diese Zielstellungen auf sozialer und technologischer Ebene gleichermaßen. Es erprobt mit einer Second-Layer-Lösung für die Blockchain eine technologische Innovation und verfolgt auf der sozialen Ebene den Ansatz einer standardisierten Dokumentation von Kompetenzen (statt Abschlüssen) weiter, in dem es Change-Prozesse hierfür anstößt, begleitet und für den weiteren Transfer aufbereitet. Der vorliegende Beitrag erläutert die Konzeption des Projektes und das Zusammenspiel technologischer und sozialer Innovationen. [Aus: Einleitung

    Rock glacier inventory of the western Nyainqêntanglha Range, Tibetan Plateau, supported by InSAR time series and automated classification

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    The western Nyainqêntanglha Range on the Tibetan Plateau reaches an elevation of 7,162 m and is characterized by an extensive periglacial environment under semi-arid climatic conditions. Rock glaciers play an important part of the water budget in high mountain areas and recent studies suggest that they may even act as climate-resistant water storages. In this study we present the first rock glacier inventory of this region containing 1,433 rock glaciers over an area of 4,622 km. To create the most reliable inventory we combine manually created rock glacier outlines with an automated classification approach. The manual outlines were generated based on surface elevation data, optical satellite imagery and a surface velocity estimation. This estimation was generated via InSAR time series analysis with Sentinel-1 data from 2016 to 2019. Our pixel-based automated classification was able to correctly identify 87.8% of all rock glaciers in the study area at a true positive rate of 69.5%. In total, 65.9% of rock glaciers are classified as transitional with surface velocities of 1–10 cm/yr. In total, 18.5% are classified as active with higher velocities of up to 87 cm/yr. The southern windward side of the mountain range contains more numerous and more active rock glaciers. We attribute this to higher moisture availability supplied by the Indian Monsoon

    In-Line Monitoring of Polyhydroxyalkanoate (PHA) Production during High-Cell-Density Plant Oil Cultivations Using Photon Density Wave Spectroscopy

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    Polyhydroxyalkanoates (PHAs) are biodegradable plastic-like materials with versatile properties. Plant oils are excellent carbon sources for a cost-effective PHA production, due to their high carbon content, large availability, and comparatively low prices. Additionally, efficient process development and control is required for competitive PHA production, which can be facilitated by on-line or in-line monitoring devices. To this end, we have evaluated photon density wave (PDW) spectroscopy as a new process analytical technology for Ralstonia eutropha (Cupriavidus necator) H16 plant oil cultivations producing polyhydroxybutyrate (PHB) as an intracellular polymer. PDW spectroscopy was used for in-line recording of the reduced scattering coefficient µs’ and the absorption coefficient µa at 638 nm. A correlation of µs’ with the cell dry weight (CDW) and µa with the residual cell dry weight (RCDW) was observed during growth, PHB accumulation, and PHB degradation phases in batch and pulse feed cultivations. The correlation was used to predict CDW, RCDW, and PHB formation in a high-cell-density fed-batch cultivation with a productivity of 1.65 gPHB·L−1·h−1 and a final biomass of 106 g·L−1 containing 73 wt% PHB. The new method applied in this study allows in-line monitoring of CDW, RCDW, and PHA formation.BMBF, 03Z22AN12, Zentrum für Innovationskompetenz innoFSPEC, Nachwuchsgruppe Angewandte Analytische Photonik (AAP

    Mechanical Competence and Bone Quality Develop During Skeletal Growth.

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    Bone fracture risk is influenced by bone quality, which encompasses bone's composition as well as its multiscale organization and architecture. Aging and disease deteriorate bone quality, leading to reduced mechanical properties and higher fracture incidence. Largely unexplored is how bone quality and mechanical competence progress during longitudinal bone growth. Human femoral cortical bone was acquired from fetal (n = 1), infantile (n = 3), and 2- to 14-year-old cases (n = 4) at the mid-diaphysis. Bone quality was assessed in terms of bone structure, osteocyte characteristics, mineralization, and collagen orientation. The mechanical properties were investigated by measuring tensile deformation at multiple length scales via synchrotron X-ray diffraction. We find dramatic differences in mechanical resistance with age. Specifically, cortical bone in 2- to 14-year-old cases exhibits a 160% greater stiffness and 83% higher strength than fetal/infantile cases. The higher mechanical resistance of the 2- to 14-year-old cases is associated with advantageous bone quality, specifically higher bone volume fraction, better micronscale organization (woven versus lamellar), and higher mean mineralization compared with fetal/infantile cases. Our study reveals that bone quality is superior after remodeling/modeling processes convert the primary woven bone structure to lamellar bone. In this cohort of female children, the microstructural differences at the femoral diaphysis were apparent between the 1- to 2-year-old cases. Indeed, the lamellar bone in 2- to 14-year-old cases had a superior structural organization (collagen and osteocyte characteristics) and composition for resisting deformation and fracture than fetal/infantile bone. Mechanistically, the changes in bone quality during longitudinal bone growth lead to higher fracture resistance because collagen fibrils are better aligned to resist tensile forces, while elevated mean mineralization reinforces the collagen scaffold. Thus, our results reveal inherent weaknesses of the fetal/infantile skeleton signifying its inferior bone quality. These results have implications for pediatric fracture risk, as bone produced at ossification centers during children's longitudinal bone growth could display similarly weak points. © 2019 American Society for Bone and Mineral Research

    High-cell-density fed-batch cultivations of Vibrio natriegens

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    Objectives: With generation times of less than 10 min under optimal conditions, the halophilic Vibrio natriegens is the fastest growing non-pathogenic bacterium isolated so far. The availability of the full genome and genetic engineering tools and its ability to utilize a wide range of carbon sources make V. natriegens an attractive host for biotechnological production processes. However, high-cell-density cultivations, which are desired at industrial-scale have not been described so far. Results: In this study we report fed-batch cultivations of V. natriegens in deep-well plates and lab-scale bioreactor cultivations at different temperatures in mineral salt medium (MSM). Upon switching from exponential glucose to constant glucose-feeding cell death was induced. Initial NaCl concentrations of 15–18 g L −1 and a temperature reduction from 37 to 30 °C had a positive effect on cell growth. The maximal growth rate in MSM with glucose was 1.36 h −1 with a specific oxygen uptake rate of 22 mmol g CDW −1 h −1 . High biomass yields of up to 55 g L −1 after only 12 h were reached. Conclusions: The shown fed-batch strategies demonstrate the potential of V. natriegens as a strong producer in industrial biotechnology.TU Berlin, Open-Access-Mittel – 202

    Recovery of the PHA Copolymer P(HB-co-HHx) With Non-halogenated Solvents: Influences on Molecular Weight and HHx-Content

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    Biodegradable and biocompatible polyhydroxyalkanoates (PHAs) are promising alternatives to conventional plastics. Based on the chain length of their monomers they are classified as short chain length (scl-) or medium chain length (mcl-) PHA polymers. The type of monomers, the composition and the molecular weight (MW) define the polymer properties. To accelerate the use of PHA as a bulk material, the downstream associated costs need to be minimized. This study focuses on the evaluation of non-halogenated solvents, especially acetone as a scl-PHA non-solvent, for the recovery of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) – P(HB-co-HHx) – with an mcl-HHx content >15 mol% and a MW average (Mw) < 2 × 105 Da. Solvents and precipitants were chosen regarding zeotrope formation, boiling point differences, and toxicity. Non-halogenated solvent-precipitant pairs were evaluated regarding the MW characteristics (MWCs) of the extracted polymer. Acetone and 2-propanol as a low toxic and zeotropic solvent-precipitant pair was evaluated at different extraction temperatures and multiple extraction times. The extraction process was further evaluated by using impure acetone for the extraction and implementing a multi-stage extraction process. Additionally, P(HB-co-HHx) extracted with three different solvents was characterized by 1H and 13C-APT NMR. The screening of precipitants resulted in a negative influence on the MWCs by ethanol precipitation for extractions with acetone and ethyl acetate, respectively. It was observed, that extractions with acetone at 70°C extracted a higher fraction of PHA from the cells compared to extractions at RT, but the Mw was decreased by 9% in average. Acetone with a 2-propanol fraction of up to 30% was still able to extract the polymer 95% as efficient as pure acetone. Additionally, when acetone and ethyl acetate were used in a multi-stage extraction process, a two-stage process was sufficient to extract 98–99% of the polymer from the cells. 1H and 13C-APT NMR analysis confirmed the monomer fraction and structure of the extracted polymers and revealed a random copolymer structure. The presented strategy can be further developed to an ecological and economically feasible PHA downstream process and thus contributes to the commercialization of low-cost PHAs.TU Berlin, Open-Access-Mittel – 2020BMBF, 031B0001C, Bioökonomie International 2014: PHABIO APP - Polyhydroxyalkanoate Biopolymere aus tierischen Abfallfetten für die Produktion von wertschöpfendem, biobasierten und abbauendem Plastik; Teilprojekt CBMBF, 031B0001B, Bioökonomie International 2014: PHABIO APP - Polyhydroxyalkanoate Biopolymere aus tierischen Abfallfetten für die Produktion von wertschöpfendem, biobasierten und abbauendem Plastik; Teilprojekt BBMBF, 031B0798C, Bioökonomie International 2017: PHABio-up - Polyhydroxyalkanoate Biopolymere aus tierischen Abfallfetten: Scale-up zur Realisierung einer industriellen Produktion - Teilvorhaben: Feedstock und Produktextraktio
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