Biodegradable metals are breaking the current paradigm in biomaterial science to develop only corrosion resistant metals. In particular, metals which consist of trace elements existing in the human body are promising candidates for temporary implant materials. These implants would be temporarily needed to provide mechanical support during the healing process of the injured or pathological tissue. Magnesium and its alloys have been investigated recently by many authors as a suitable biodegradable biomaterial. In this investigative review we would like to summarize the latest achievements and comment on the selection and use, test methods and the approaches to develop and produce magnesium alloys that are intended to perform clinically with an appropriate host response.

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Degradable biomaterials based on magnesium corrosion

In the laser treatment of a workpiece (9), e.g. for surface hardening, melting, alloying, cladding, welding or cutting, the adverse effect of reflectivity of the surface, when a pure, monochromatic laser (6) is used, is remedied by the simultaneous application of a relatively shorter wavelength beam (1). The two beams (1)(5) may be combined by a beam coupler (4) or may reach the workpiece (9) by separate optical paths (not shown). The shorter wavelength beam (1) improves the coupling efficiency of the higher- powered laser beam (5).

Laser Material Processing

The history of biodegradable magnesium implants: a review.

OBJECTIVES: This study developed prevalence estimates of gambling-related disorders in the United States and Canada, identified differences in prevalence among population segments, and identified changes in prevalence over the past 20 years METHODS: A meta-analytic strategy was employed to synthesize estimates from 119 prevalence studies This method produced more reliable prevalence rates than were available from any single study RESULTS: Prevalence estimates among samples of adolescents were significantly higher than estimates among samples of adults for both clinical (level 3) and subclinical (level 2) measures of disordered gambling within both lifetime and past-year time frames (eg, 39% vs 16% for lifetime estimates of level 3 gambling) Among adults, prevalence estimates of disordered gambling have increased significantly during the past 20 years CONCLUSIONS: Membership in youth, treatment, or prison population segments is significantly associated with experiencing gambling-related disorders

/pdf/estimating-the-prevalence-of-disordered-gambling-behavior-in-homkgp1ft5.pdf

Estimating the prevalence of disordered gambling behavior in the United States and Canada: a research synthesis.

http://lbmd.coe.pku.edu.cn/PDF/2009biomaterials01.pdf

In vitro corrosion and biocompatibility of binary magnesium alloys

Developments in metallic biodegradable stents.

Fe-Mn alloys for metallic biodegradable stents: Degradation and cell viability studies

An Fe–35 wt-%Mn alloy, aimed to be used as a metallic degradable biomaterial for stent applications, was prepared via a powder metallurgy route. The effects of processing conditions on the microstructure, mechanical properties, magnetic susceptibility and corrosion behaviour were investigated and the results were compared to those of the SS316L alloy, a gold standard for stent applications. The Fe35Mn alloy was found to be essentially austenitic with fine MnO particles aligned along the rolling direction. The alloy is ductile with a strength approaching that of wrought SS316L. It exhibits antiferromagnetic behaviour and its magnetic susceptibility is not altered by plastic deformation, providing an excellent MRI compatibility. Its corrosion rate was evaluated in a modified Hank's solution, and found superior to that of pure iron (slow in vivo degradation rate). In conclusion, the mechanical, magnetic and corrosion characteristics of the Fe35Mn alloy are considered suitable for further development ...

Iron–manganese: new class of metallic degradable biomaterials prepared by powder metallurgy

Design of a pseudo-physiological test bench specific to the development of biodegradable metallic biomaterials

Designing materials having suitable mechanical properties and targeted degradation behavior is the key for the development of biodegradable materials for medical applications, including stents. A series of Fe-Mn alloys was developed with the objective to obtain mechanical properties similar to those of stainless steel 316L and degradation behavior more suited than pure iron. Four alloys with Mn content ranging between 20 and 35 wt % were compared in this study. Their microstructure, mechanical properties, magnetic properties as well as degradation behavior were carefully investigated. Results show that their microstructure is mainly composed of gamma phase with the appearance of epsilon phase in alloys having a lower Mn content. The yield strength and elongation of alloys was comprised between 234 MPa and 32% for Fe-35%Mn alloy to 421 MPa and 7.5% for the Fe-20%Mn alloy. All alloys show similar magnetic susceptibility ( approximately 1.8 x 10(-7) m(3)/kg) in the quenched condition. This magnetic susceptibility remains constant after plastic deformation for all the tested alloys except for the Fe-20%Mn alloy. The corrosion rate was higher than pure iron. Among the alloys studied in this work, the Fe-35%Mn alloy shows mechanical properties and degradation behavior closely approaching those required for biodegradable stents application.

Dominique Dubé

Papers

Developments in metallic biodegradable stents.

Fe-Mn alloys for metallic biodegradable stents: Degradation and cell viability studies

Iron–manganese: new class of metallic degradable biomaterials prepared by powder metallurgy

Design of a pseudo-physiological test bench specific to the development of biodegradable metallic biomaterials

Degradable metallic biomaterials: design and development of Fe-Mn alloys for stents.