Magnesium degradation observed in situ under flow by synchrotron radiation based microtomography

The use of degradable magnesium based implants is becoming clinically relevant, e.g. for the use as bone screws. Still there is a lack of analyzing techniques to characterize the in vitro degradation behavior of implant prototypes. The aim of this study was to design an in situ environment to continuously monitor the degradation processes under physiological conditions by time-lapse SRμCT. The use of physiological conditions was chosen to get a better approach to the in vivo situation, as it could be shown by many studies, that these conditions change on the one hand the degradation rate and on the other hand also the formed degradation products. The resulting in situ environment contains a closed bioreactor system to control and monitor the relevant parameters (37°C, 5 % O2, 20 % CO2) and to grant sterility of the setup. A flow cell was designed and manufactured from polyether etherketone (PEEK), which was chosen because of the good mechanical properties, high thermal and chemical resistance and radiographic translucency. Sterilization of the system including the sample was reached by a transient flush with 70 % ethanol and subsequent replacement by physiological medium (Modified Eagle Medium alpha). As proof of principle it could be shown that the system remained sterile during a beamtime of several days and that the continuous SRμCT imaging was feasible. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Grundwasserueberwachungsprogramm Ergebnisse der Beprobung 1992

The Baden-Wuerttemberg monitoring network for assessment of the actual state of the ground water and of possible development trends is part of a preventive ground water pollution abatement program. The monitoring network was extended considerably in 1992. The organizational structure was changed through takeover of the monitoring networks owned by Verdichtungsmessnetz Wasserversorgung by the water supply utilities. The analytical data compiled in 1992 are presented placing emphasis on the ground water data obtained for critical substances such as nitrates, herbicides, pesticides, and highly volatile halogenated hydrocarbons. Numerous further results from different types of measuring points are compiled in concise statistical surveys. (orig.)Das Land Baden-Wuerttemberg betreibt im Rahmen eines vorbeugenden Grundwasserschutzprogrammes ein umfangreiches Messnetz zur Erfassung des Ist-Zustandes des Grundwassers sowie von moeglichen Entwicklungstendenzen. Dieses Messnetz konnte im Jahre 1992 wesentlich erweitert werden. Als organisatorische Aenderung ist die Uebernahme des Messnetzbetriebes des Verdichtungsmessnetzes Wasserversorgung durch die Wasserversorgungswirtschaft zu erwaehnen. Die Analysendaten aus der Beprobungsrunde 1992 werden in dem vorliegenden Bericht vorgestellt. Schwerpunktmaessig werden dabei die Grundwasserbefunde einiger besonders umweltrelevanter Kenngroessen wie Nitrat, die Pflanzenbehandlungs- und Schaedlingsbekaempfungsmittel und die leichtfluechtigen Halogenkohlenwasserstoffe behandelt. Darueberhinaus wird eine Vielzahl weiterer Ergebnisse der verschiedenen Messstellenarten anhand statistischer Uebersichten in verdichteter Form praesentiert. (orig.)Available from TIB Hannover: F93B1115 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEMinisterium fuer Umwelt des Landes Baden-Wuerttemberg, Stuttgart (Germany)DEGerman