In situ characterization of the functional degradation of a [001] orientated Fe–Mn–Al–Ni single crystal under compression using acoustic emission measurements

Acoustic emission (AE) measurements were conducted in situ during cyclic compressive loading on an [ 00 1 over line ] orientated single crystal of Fe-Mn-Al-Ni shape memory alloy to study functional degradation of its superelastic response. The acoustic investigations were corroborated by optical microscopy, employing video imaging, and transmission electron microscopy. The analysis of acoustic emissions recorded during repeated loading and unloading sessions revealed two categories of AE signals that are differed by their characteristics in time and frequency domains. These two distinct types of AE signals were related to two underlying mechanisms: (i) the nucleation and reverse transformation of stress-induced (twinned) martensite, and (ii) the lateral growth and shrinkage of one dominant martensite variant and related dislocation activities, respectively. In addition, an asymmetry in the AE activity during forward and reverse transformation during mechanical loading and unloading was detected. In particular, an unexpected high AE activity was observed during the superelastic unloading of martensitic microstructure from the point of maximum load/strain. This effect was attributed to the reverse transformation of small, tiny areas of martensite as well as to unpinning and annihilation effects related to dislocations. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

Bone sialoprotein immobilized in collagen type I enhances bone regeneration in vitro and in vivo

The use of bioactive molecules is a promising approach to enhance the bone healing properties of biomaterials. The aim of this study was to define the role of bone sialoprotein (BSP) immobilized in collagen type I in various settings. In vitro studies with human primary osteoblasts in mono- or in co-culture with endothelial cells demonstrated a slightly increased gene expression of osteogenic markers as well as an increased proliferation rate in osteoblasts after application of BSP immobilized in collagen type I. Two critical size bone defect models were used to analyze bone regeneration. BSP incorporated in collagen type I increased bone regeneration only marginally at one concentration in a calvarial defect model. To induce the mechanical stability, three-dimensional printing was used to produce a stable porous cylinder of polylactide. The cylinder was filled with collagen type I and immobilized BSP and implanted into a femoral defect of critical size in rats. This hybrid material was able to significantly induce bone regeneration. Our study clearly shows the osteogenic effect of BSP when combined with collagen type I as carrier and thereby offers various approaches and options for its use as bioactive molecule in bone substitute materials

Bone Sialoprotein Immobilized in Collagen Type I Enhances Angiogenesis In Vitro and In Ovo

Bone fracture healing is a multistep process, including early immunological reactions, osteogenesis, and as a key factor, angiogenesis. Molecules inducing osteogenesis as well as angiogenesis are rare, but hold promise to be employed in bone tissue engineering. It has been demonstrated that the bone sialoprotein (BSP) can induce bone formation when immobilized in collagen type I, but its effect on angiogenesis still has to be characterized in detail. Therefore, the aim of this study was to analyse the effects of BSP immobilized in a collagen type I gel on angiogenesis. First, in vitro analyses with endothelial cells (HUVECs) were performed detecting enhancing effects of BSP on proliferation and gene expression of endothelial markers. A spheroid model was employed confirming these results. Finally, the inducing impact of BSP-collagen on vascular density was proved in a yolk sac membrane assay. Our results demonstrate that BSP is capable of inducing angiogenesis and confirm that collagen type I is the optimal carrier for this protein. Taking into account former results, and literature showing that BSP also induces osteogenesis, one can hypothesize that BSP couples angiogenesis and osteogenesis, making it a promising molecule to be used in bone tissue regeneration

Handreichung Pflege und Gesundheit

Diese Handreichung ist das Ergebnis der Zusammenarbeit von vier geförderten Projekten und der wissenschaftlichen Begleitung des Bund-Länder-Wettbewerbs „Aufstieg durch Bildung: offene Hochschulen“. Sie basiert auf der fachspezifischen Vernetzung von Projekten, die auf die Planung und Entwicklung von hochschulischen (weiterbildenden) Studienformaten im Bereich Pflege und Gesundheit fokussieren. Dabei geht es auf einer übergreifenden Ebene um den aktuellen Stand der bildungs- und hochschulpolitischen Diskussion in Deutschland zum Thema Akademisierung von Pflege- und Gesundheitsberufen. Zudem werden planungs- und entwicklungsspezifische Herausforderungen und Fragestellungen aufgezeigt, die Studienangebote in diesen Fachdisziplinen betreffen. Zentrales Anliegen der Autorinnen und Autoren ist, konkrete Perspektiven und Entwicklungsmöglichkeiten aufzuzeigen und Empfehlungen für Angebotsentwicklerinnen und -entwickler an Hochschulen zu formulieren, die vor ähnlichen Herausforderungen stehen bzw. zukünftig stehen werden. (Hrsg.

57Fe Mössbauer study into oxygen vacancy disorder in (Ba0.5Sr0.5)(Co0.8Fe0.2)O3−δ

A 57Fe Mössbauer study of mixed ionic electronic conducting (Ba0.5Sr0.5)(Co0.8 57Fe0.08Fe0.12)O3−δ (BSCF) has been made on samples of different oxygen content. The room-temperature spectra are found to depend strongly on oxygen stoichiometry. They reveal two magnetically and chemically different environments of the iron probes whose charge states and oxygen coordination are discussed. Analysis of spectral intensities provides confirmation of the close similarity of formation energies of different types of oxygen vacancies in BSCF. It is also shown that the distribution of oxygen vacancies on their sites of different coordination is far from random

Bone Sialoprotein Immobilized in Collagen Type I Enhances Angiogenesis In Vitro and In Ovo

Bone fracture healing is a multistep process, including early immunological reactions, osteogenesis, and as a key factor, angiogenesis. Molecules inducing osteogenesis as well as angiogenesis are rare, but hold promise to be employed in bone tissue engineering. It has been demonstrated that the bone sialoprotein (BSP) can induce bone formation when immobilized in collagen type I, but its effect on angiogenesis still has to be characterized in detail. Therefore, the aim of this study was to analyse the effects of BSP immobilized in a collagen type I gel on angiogenesis. First, in vitro analyses with endothelial cells (HUVECs) were performed detecting enhancing effects of BSP on proliferation and gene expression of endothelial markers. A spheroid model was employed confirming these results. Finally, the inducing impact of BSP-collagen on vascular density was proved in a yolk sac membrane assay. Our results demonstrate that BSP is capable of inducing angiogenesis and confirm that collagen type I is the optimal carrier for this protein. Taking into account former results, and literature showing that BSP also induces osteogenesis, one can hypothesize that BSP couples angiogenesis and osteogenesis, making it a promising molecule to be used in bone tissue regeneration