Properties of Biodegradable Alloys Usable for Medical Purposes

Magnesium alloys are promising materials for production of biodegradable implants that may be used for fixation of fractured bones. Magnesium itself is an essential element that plays important roles in many biological processes. However, some common alloying elements of magnesium alloys such as aluminium or copper may cause health problems to the organism. A major problem is the high corrosion rate of magnesium and its alloys in physiological environment that contains chloride anions. Currently, the research focuses on alloys doped by rare-earth elements and zinc. All these elements affect corrosion resistance and mechanical properties of magnesium alloys. This work was dealing with the study of Mg-Gd binary alloy and Mg-Gd-Y, Mg-Gd-Zn ternary alloys that were prepared from pure metals by melting in induction furnace. Various alloy compositions were tested. Corrosion behaviours in 9 M NaCl saline environments (exposure tests, potentiodynamic measurements) were studied on alloys in the cast state. Good corrosion resistance and uniform corrosion were observed in the case of binary Mg-Gd alloy. The influence of the addition of Y or Zn to the Mg-Gd system is discussed

Properties of Biodegradable Alloys Usable for Medical Purposes

Magnesium alloys are promising materials for production of biodegradable implants that may be used for fixation of fractured bones. Magnesium itself is an essential element that plays important roles in many biological processes. However, some common alloying elements of magnesium alloys such as aluminium or copper may cause health problems to the organism. A major problem is the high corrosion rate of magnesium and its alloys in physiological environment that contains chloride anions. Currently, the research focuses on alloys doped by rare-earth elements and zinc. All these elements affect corrosion resistance and mechanical properties of magnesium alloys. This work was dealing with the study of Mg-Gd binary alloy and Mg-Gd-Y, Mg-Gd-Zn ternary alloys that were prepared from pure metals by melting in induction furnace. Various alloy compositions were tested. Corrosion behaviours in 9 M NaCl saline environments (exposure tests, potentiodynamic measurements) were studied on alloys in the cast state. Good corrosion resistance and uniform corrosion were observed in the case of binary Mg-Gd alloy. The influence of the addition of Y or Zn to the Mg-Gd system is discussed

Biodegradability of Metal Alloys: in vivo Testing

Introduction and aim: The standard material used for osteosynthesis of the facial skeleton is the titan and its compounds. One of the disadvantages of the conventional material is the need for its extraction in indicated cases. Degradable material offer a solution to the situation. In the past, materials based on polylactic or polyglycolic acid were used for these purposes. It clinically proved to be unsatisfactory. The modern solution is the use of biodegradable metal alloys. The authors present original research on the degradation of metal materials based on magnesium and zinc on the biomodels. Materials and methods: A total of 12 animal models (rabbits) were used. Screws of 3 types of metals (Zn-2Mg and WE43 degradable alloys and the titanium as a standard material) were implanted in the rabbit's tibias. The animals were euthanasied in 4-weeks intervals, samples of bone tissue with an implanted material have been scaned under mikrofocus CT and were histologically examined. The rate of degradation of the materials was examined. Results: Time period of degradation of the material WE43 under physiological conditions has been shown to be too short to stabilize the fracture. Material of Zn-2 mg during the 16 weeks showed a minimum ability to degradation. Both materials have demonstrated reasonable biological properties. Conclusion: Degradable materials based on magnesium and zinc are from the biological point of view matching materials. The results of this research indicates that the use of both types of alloys does not satisfy the materials requirments, i.e. retained strength for 12-24 weeks and degradation in reasonable time frame.

Flood Modelling and Visualizations of Floods Through 3D Open Data

Part 3: Water and HydrosphereInternational audienceThis paper is devoted to 3D modelling at the city level from data sources considered as open. The open data presented in this paper enable free usage, modifications, and sharing by anyone for any purpose. The main motivation was to verify feasibility of a 3D visualization of floods purely based on open technologies and data. The presented state-of-the-art analysis comprises the evaluation of available 3D open data sources, including formats, Web-based technologies, and software used for visualizations of 3D models. A pilot Web application visualizing floods was developed to verify the applicability of discovered data sources. 3D visualizations of terrain models, 3D buildings, flood areas, flood walls and other related information are available in a pilot application for a selected part of the city of Prague. The management of different types of input data, the design of interactive functionality including navigation aids, and actual limitations and opportunities for future development are discussed in detail at the end