Design and characterizations of novel biodegradable Zn-Cu-Mg alloys for potential biodegradable implants

Publication date: 5 March 2017
Source:Materials & Design, Volume 117
Author(s): Zibo Tang, Hua Huang, Jialin Niu, Lei Zhang, Hua Zhang, Jia Pei, Jinyun Tan, Guangyin Yuan
Zn-3Cu-xMg (x=0, 0.1, 0.5 and 1.0wt.%) alloys were developed as potential biodegradable metallic materials in this study. The mechanical properties, corrosion behavior and in vitro cytocompatibility of Zn-3Cu-xMg alloys were studied systematically to evaluate the feasibility as biodegradable implant materials. The secondary phase in as-cast and as-extruded Zn-3Cu alloy was CuZn5 phase. Mg2Zn11 phase newly formed and precipitated by Mg addition. The volume fraction of Mg2Zn11 phase increased gradually with increasing Mg concentration. As a result, yield strength was improved from 213.7 to 426.7MPa and increased by 99.7% while elongation decreased from 47.1% to 0.9%. Besides, biocompatibility was improved apparently and in vitro corrosion rates increased from 11.4 to 43.2μmyear⁻¹, which is more suitable for clinic application. The present research indicated that the newly developed alloys could be promising candidates for biomedical use due to the proper mechanical properties, degradation rate and acceptable biocompatibility.

Graphical abstract

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Microstructure and mechanical strength of near- and sub-micrometre grain size copper prepared by spark plasma sintering

Publication date: 5 March 2017
Source:Materials & Design, Volume 117
Author(s): K.N. Zhu, A. Godfrey, N. Hansen, X.D. Zhang
Spark plasma sintering (SPS) has been used to prepare fully dense samples of copper in a fully recrystallized condition with grain sizes in the near- and sub-micrometre regime. Two synthesis routes have been investigated to achieve grain size control: (i) SPS at different temperatures from 800 to 1000°C, and (ii) SPS at 800°C followed by annealing at temperatures from 950 to 1050°C. By use of an initial spherical powder with an average particle diameter of ≈0.5μm, samples with average grain sizes in the range from 0.5 to 3μm have been prepared. Microstructural examination based on both transmission electron microscope, and on electron back-scatter diffraction studies, confirms the samples are in a nearly fully recrystallized condition, with grains that are dislocation-free, and have a random texture, with a high fraction of high angle boundaries. The mechanical strength of the samples has been probed using hardness measurements and tensile testing, revealing an enhanced strength for samples with grain sizes less than ≈1μm.

Graphical abstract

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Zinc subjected to plastic deformation by complex loading and conventional extrusion: Comparison of the microstructure and mechanical properties

Publication date: 5 March 2017
Source:Materials & Design, Volume 117
Author(s): K. Pieła, M. Wróbel, K. Sztwiertnia, M. Jaskowski, J. Kawałko, M. Bieda, M. Kiper, A. Jarzębska
The microstructure and properties of cast and hot extruded zinc subjected to plastic deformation by conventional extrusion and by extrusion with a forward-backward rotating die (KoBo) were studied. KoBo significantly increased the mechanical properties of both initial materials compared with conventional extrusion. The improvement of the mechanical properties is related to the lower temperature at which the KoBo process can be carried out. Extrusion with a forward-backward rotating die leads to grain refinement and promotes the formation of a composite-like microstructure with a hard matrix, forming an interconnected network of boundaries filled with a softer phase. New areas of application for zinc obtained by the KoBo method are opened.

Graphical abstract

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Editorial: an Update on JOPM progress and performance

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ApoE, ApoE Receptors, and the Synapse in Alzheimer's Disease

Publication date: Available online 2 January 2017
Source:Trends in Endocrinology & Metabolism
Author(s): Courtney Lane-Donovan, Joachim Herz
As the population ages, neurodegenerative diseases such as Alzheimer's disease (AD) are becoming a significant burden on patients, their families, and health-care systems. Neurodegenerative processes may start up to 15 years before outward signs and symptoms of AD, as evidenced by data from AD patients and mouse models. A major genetic risk factor for late-onset AD is the ɛ4 isoform of apolipoprotein E (ApoE4), which is present in almost 20% of the population. In this review we discuss the contribution of ApoE receptor signaling to the function of each component of the tripartite synapse – the axon terminal, the postsynaptic dendritic spine, and the astrocyte – and examine how these systems fail in the context of ApoE4 and AD.



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Bilateral Half-Head Comparison of 1% Anthralin Ointment in Children with Alopecia Areata

Abstract

Background/Objectives

Alopecia areata (AA) is one of the most difficult skin diseases to manage well. In children, anthralin is commonly used for the treatment of AA. Available research consists of a limited number of uncontrolled trials that assessed the effectiveness of anthralin in promoting hair growth in patients with AA. The objective of this study was to validate the clinical effectiveness of short-contact anthralin 1% ointment in children with AA.

Methods

Thirty children with chronic, severe, treatment-refractory, extensive AA were treated with 1% anthralin ointment. One side of the scalp was treated with anthralin for 12 months and the other side was left untreated. Outcomes were evaluated according to the Severity of Alopecia Tool (SALT) score.

Results

The mean time to first response in terms of new hair growth was 3 months and the mean time to maximal response was 9 months. In the first 12-month period, 10 patients (33.4%) achieved complete response to treatment and 11 patients (36.6%) had a partial response. Of the 11 patients with partial response at the end of the first year, 6 achieved a complete response before the end of the study. Total SALT scores for the entire scalp decreased from the end of the first year to the end of the 2-year period. No serious adverse events were observed.

Conclusion

Anthralin 1% is an effective therapy for AA and should be continued at least 9 months. At 9 months of topical anthralin therapy, the patients with at least a 50% reduction in their pretreatment SALT scores should continue the same treatment for at least 1 year. Anthralin is safe in children with chronic, severe, treatment-refractory, extensive AA.

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Three-dimensional Facial Anatomy: Structure and Function as It Relates to Injectable Neuromodulators and Soft Tissue Fillers

Background: The advent of new neuromodulators and soft-tissue fillers continues to expand the nonsurgical repertoire of the core cosmetic physician. Methods: The authors review relevant facial anatomy as it relates to facial aging and the resultant structural changes that occur. These changes are important for the cosmetic physician to identify and understand in order to perform both safe and effective placement of neuromodulators and soft-tissue fillers. In this anatomic review, the authors review key structures that serve as landmarks for successful treatment using both neuromodulators and fillers. Conclusions: Knowledge of key facial anatomical structures allows the cosmetic physician to perform injection of neuromodulators and soft-tissue fillers in a reproducible manner to optimizing patient safety and results. Copyright (C) 2016 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Society of Plastic Surgeons. All rights reserved.

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