Impact based surface treatments with adequate kinetic energy have favorable effects on promoting cell-substrate interactions, reducing bacterial adhesion, and enhancing fatigue performance of metallic biomaterials. Here, we used both numerical and experimental approaches to evaluate the potential of these treatments for addressing the major issue associated with the application of pure iron in biomedical implants, i.e. its low corrosion rate. Despite the efficiency of impact based surface treatments in modulating the degradation rate of pure iron, the maximum reported depth of the affected surface layer is still limited, even when extreme process parameters are used. To address this issue, herein, two impact based treatments were adjusted to trigger the dislocation activities that facilitate grain refinement in pure iron using multi-directional inclined impacts. An alternative approach of severe shot peening (SSP) was developed and compared with ultrasonic shot peening (USP). The effect of both treatments and variations of their key parameters were analyzed considering the significant role of shear bands and dislocation cells in the grain refinement mechanism of pure α-iron. Microstructural, mechanical and electrochemical properties of the treated material were analyzed. The observations showed extension of the grain refined layers for the specimens subjected to multidirectional oblique impacts compared to the ones treated in the classic manner using normal impacts. The results imply that by adapting peening parameters, it would be possible to effectively create a thick surface layer with properties that can accelerate the biodegradation of pure iron boosting its potential to meet clinical requirements for temporary hard tissue implants.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104476 | DOI Listing |
J Environ Sci (China)
July 2025
Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Siderite tailings is a potentially cost-free iron (Fe) source for arsenic (As) fixation in hazardous arsenic-calcium residues (ACR) as stable scorodite. In this study, a pure siderite reagent was employed to investigate the mechanism and optimal conditions for As fixation in ACR via scorodite formation, while the waste siderite tailings were used to further demonstrate the cotreatment method. The cotreatment method starts with an introduction of sulfuric acid to the ACR for As extraction and gypsum precipitation, and is followed by the addition of HO to oxidize As(III) in the extraction solutions and finalized by adding siderite with continuous air injection for scorodite formation.
View Article and Find Full Text PDFEcotoxicol Environ Saf
January 2025
Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, Wuhan 430074, PR China. Electronic address:
Microorganisms that utilize organic matter to reduce Fe oxides/hydroxides constitute the primary geochemical processes controlling the formation of high-arsenic (As) groundwater. Biogenic secondary iron minerals play a significant role in As migration. However, the influence of quinone electron shuttles and competitive anionic phosphate on this process has not been thoroughly studied.
View Article and Find Full Text PDFNano Lett
January 2025
Center for Quantum Nanoscience, Institute for Basic Science, Seoul 03760, South Korea.
We demonstrate the reversible control of interactions between a local molecular spin, hosted within an iron phthalocyanine (FePc) molecule, and the conduction electrons of a supporting Au(111) surface. Using the tip of a scanning tunneling microscope, we deliberately and reversibly manipulate the adsorption configuration of the molecule relative to the underlying substrate lattice. Different rotation configurations lead to noticeable changes in the differential conductance measured on the FePc molecules.
View Article and Find Full Text PDFUpdates Surg
January 2025
Division of Visceral Surgery, Department of General Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
Background: Metabolic/bariatric surgery (MBS) remains the most effective and long-lasting treatment for obesity and its complications. Apart from any surgical complications, the often less obvious but possibly severe side-effects of nutritional deficiencies have become of interest in recent years. OAGB is known to come with the need for thorough supplementation.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institute for Chemical Research, Kyoto University, Gokasho, Uji 611-0011, Japan.
Nanoclusters are nanometer-sized molecular compounds characterized by significant metal-metal bonding and low average oxidation states, and they exhibit unique properties distinct from those of small metal complexes or nanoparticles. Unlike noble metals stable in metallic forms, the synthesis of nanometer-sized iron clusters has been precluded by the relatively weak iron-iron bonds and the high reactivity of low oxidation state iron, despite the extensive history of molecular iron compounds. Here, we report the synthesis and characterization of a cationic 55-atom iron cluster with a 1.
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