CO2-crystal wettability in potassic magmas. Implications for eruptive dynamics in light of experimental evidence for heterogeneous nucleation.

The volatile content in magmas is fundamental for the triggering and style of volcanic eruptions. Carbon dioxide, the second most abundant volatile component in magmas after H2O, is the first to reach saturation upon ascent and depressurization. We investigate experimentally CO2-bubble nucleation in trachybasalt and trachyte melts at high temperature and high pressure (HT and HP) through wetting-angle measurements on different (sialic, mafic or oxide) phenocryst phases. The presence of crystals lowers the supersaturation required for CO2- bubble nucleation up to 37 per cent (heterogeneous nucleation, HeN), with a minor role of mineral chemistry. Different from H2O-rich systems, feldspar crystals are effective in reducing required supersaturation for bubble nucleation. Our data suggest that leucite, the dominant liquidus phase in ultrapotassic systems at shallow depth (i.e. <100 MPa), facilitates late-stage, extensive magma vesiculation through CO2 HeN, which may explain the shifting of CO2-rich eruptive systems towards an apparently anomalous explosive behaviour

The importance of hole concentration in establishing carrier-mediated ferromagnetism in Mn doped Ge

In the present work, we have prepared Mn-doped Ge using different annealing approaches after Mn ion implantation, and obtained samples with hole concentrations ranging from 10^18 to 2.1x10^20 cm^-3, the latter being the highest reported so far. Based on the magnetotransport properties of Mn doped Ge, we argue that the hole concentration is a decisive parameter in establishing carrier-mediated ferromagnetism in magnetic Ge.Comment: 7 pages, 3 figure

Datenintegration, Wissensrepräsentation und Datenanalyse – Werkzeuge zur systematischen Untersuchung von Einflussfaktoren auf das Langzeit-Outcome nephrologischer Patienten

Das Gesundheitssystem wird sich durch die Digitalisierung in der Zukunft radikal ändern. Besserer Informationsaustausch durch vernetzte Fallakten, neue Versorgungsformen wie z.B. Telemedizinanwendungen können zukünftig das Problem des Fachärztemangels in strukturschwachen Gegenden vermindern. Neue Mobile Health Anwendungen werden die Patienten aktiver in Therapiemöglichkeiten einbinden und das Patient Empowerment verbessern. Zusätzlich werden durch die Digitalisierung immer mehr Daten produziert, die einen Betrag zur medizinischen Forschung und Verbesserung von Therapien leisten können. Neben den Herausforderungen zum Datenschutz und zur Datensicherheit, müssen auch Fragen zur Interoperabilität, Nutzen und Transparenz geklärt werden. Diese Arbeit untersucht exemplarisch an drei konkreten Beispielen (zur Datenintegration, Wissensrepräsentation und Datenanalyse), welche Herausforderungen und Lösungen möglich sind, um medizinische Daten effektiv zu nutzen und die Forschung und Routineversorgung zu verbessern. In der Studie zur Datenintegration wurde untersucht, inwieweit sich eine auf einem relationalen Datenbankschema basierende medizinische Routinedatenbank mit Langzeitdaten von transplantierten Patienten, in eine Ontologie-basierte Forschungsdatenbank wie i2b2, ohne Informationsverlust überführen lässt. Des Weiteren wurde in der Studie zur Wissensrepräsentation untersucht, wie sich mit Hilfe von Open Source Entwicklungswerkzeugen eine Applikation zur Visualisierung von Informationen aus strukturierten und unstrukturierten medizinischen Daten implementieren lässt. Mit der entwickelten Applikation kann das medizinische Personal ohne Programmierkenntnisse Informationen aus dem medizinischen Datenpool extrahieren und systematisch analysieren. Das Thema Datenanalyse wurde durch die Studie zum akuten Nierenversagen näher beleuchtet. In dieser Studie wurde ein Algorithmus implementiert, der in einer großen Kohorte aus stationären Patientendaten, das Ereignis akutes Nierenversagen (ANV) detektieren kann. Nach der statistischen Auswertung der Ergebnisse dieses Algorithmus, konnte die Kohorte im Hinblick auf das Auftreten von akuten Nierenversagen und den damit verbundenen Krankheitscharakteristika und Risikoassoziationen umfassend beschrieben werden.The digitalization will radically transform the healthcare system in the future. New forms of health care e.g. telemedicine or interconnected health records have the capability to reduce the problem of the shortage of medical experts in rural areas. New mobile health applications will involve patients more actively in their treatment options and will improve patient empowerment. Furthermore, the digitalization is producing more and more data, which should foster medical research and further improve of therapies. In addition to the challenges of data protection and data security, questions about interoperability, medical value and transparency must also be addressed. This thesis is based on three concrete examples (for data integration, knowledge representation and data analysis) and investigates which challenges and solutions are possible to use medical data effectively and to improve research and routine medical care. The study on data integration examined the extent to which a relational database for routine medical care with long-term data from transplanted patients can be transferred to an ontology-based research database such as i2b2 without loss of information. The study on the representation of knowledge examined the implementation of an application for the visualization of information from structured and unstructured medical data by using open source development tools. With the fully developed application, medical personnel can now extract information from the medical data base and easily analyse data without programming knowledge. The study on acute kidney failure examined the topic of data analysis in more detail. In this study, an algorithm was implemented that can detect the event of acute kidney failure in a large cohort of inpatient hospital data. After the statistical analysis of the results of this algorithm, the cohort could be comprehensively described with regard to the occurrence of acute kidney failure and the associated disease characteristics and risk associations

Protocol for High-Yield Production of Photo-Leucine-Labeled Proteins in Escherichia coli

UV-cross-linking mass spectrometry is an emerging technique to obtain structural information of biomacromolecules and their complexes; in vivo; and; in vitro; . In particular, certain photo-reactive amino acids (pA) such as photo-leucine (pLeu) and photo-methionine can provide unique short-distance information on the structural core regions of proteins. Here, we present a protocol for high-yield incorporation of pLeu in proteins recombinantly expressed in; Escherichia coli; . The protein of interest is expressed at high cell densities, which reduces the required amount of the pA by a factor of 10, as compared to the standard protocols, while maintaining high incorporation rates. For the two chaperones, trigger factor and SecB, up to 3 mg of pLeu-labeled protein were thus obtained from 100 mL of cell culture, with label incorporation rates of up to 34%. For trigger factor, UV-induced cross-linking leads to the identification of 12 cross-links that are in agreement with the published three-dimensional structures. The accessibility of milligram amounts of pLeu-labeled proteins at low costs will be highly useful to address structural biology questions

Nonvolatile bipolar resistive switching in Au/BiFeO3/Pt

Nonvolatile bipolar resistive switching has been observed in an Au/BiFeO3/Pt structure, where a Schottky contact and a quasi-Ohmic contact were formed at the Au/BiFeO3 and BiFeO3/Pt interface, respectively. By changing the polarity of the external voltage, the Au/BiFeO3/Pt is switched between two stable resistance states without an electroforming process. The resistance ratio is larger than two orders of magnitude. The resistive switching is understood by the electric field - induced carriers trapping and detrapping, which changes the depletion layer thickness at the Au/BiFeO3 interface.Comment: 23 pages, 4 figures, accepted by J. Appl. Phy

A new exactly solvable quantum model in N dimensions

An N-dimensional position-dependent mass Hamiltonian (depending on a parameter \lambda) formed by a curved kinetic term and an intrinsic oscillator potential is considered. It is shown that such a Hamiltonian is exactly solvable for any real positive value of the parameter \lambda. Algebraically, this Hamiltonian can be thought of as a new maximally superintegrable \lambda-deformation of the N-dimensional isotropic oscillator and, from a geometric viewpoint, this system is just the intrinsic oscillator potential on an N-dimensional hyperbolic space with nonconstant curvature. The spectrum of this model is shown to be hydrogenlike, and their eigenvalues and eigenfunctions are explicitly obtained by deforming appropriately the symmetry properties of the N-dimensional harmonic oscillator. A further generalization of this construction giving rise to new exactly solvable models is envisaged.Comment: 12 pages, 2 figures; comments added and typos correcte

Decisive role of oxygen vacancy in ferroelectric vs. ferromagnetic Mn-doped BaTiO3 thin films

Single-phase perovskite 5 at.% Mn-doped and undoped polycrystalline BaTiO3 thin films have been grown under different oxygen partial pressures by pulsed laser deposition on platinum-coated sapphire substrates. Ferroelectricity is only observed for the Mn-doped and undoped BaTiO3 thin films grown under relatively high oxygen partial pressure. Compared to undoped BaTiO3, Mn-doped BaTiO3 reveals a low leakage current, increased dielectric loss, and a decreased dielectric constant. Ferromagnetism is seen on Mn-doped BaTiO3 thin films prepared under low oxygen partial pressure and is attributed to the formation of bound magnetic polarons (BMPs). This BMP formation is enhanced by oxygen vacancies. The present work confirms a theoretical work from C. Ederer and N. Spaldin on ferroelectric perovskites [Nature Mat. 3, 849 (2004)] which shows that the existence of ferroelectricity is incompatible with the existence of a spontaneous magnetization in Mn-doped BaTiO3 thin films.Comment: 36 pages, 11 figure