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Food Additives & Contaminants. Part A,... Dec 2021The release of metal elements from stainless-steel products in contact with food may endanger human health. To protect human health, different countries or international...
The release of metal elements from stainless-steel products in contact with food may endanger human health. To protect human health, different countries or international organisations have formulated corresponding regulations or technical guidelines. Limits for only five metal elements are stipulated in the China National Food Safety Standard (GB 4806.9) and food simulants and test conditions are fixed regardless of the actual use condition. In this study, inductively coupled plasma mass spectroscopy and inductively coupled plasma optical emission spectroscopy were used to measure the concentrations of six metal contaminants and impurities and 11 metals and alloy component released from stainless-steel sheets on Chinese market. The effects were also investigated on metal release of six grades (201, 202, 304, 430, 443, and 30Cr13) and 6 exposure conditions (food simulant 5 g L citric acid or 4 vol% acetic acid, contact temperature 70 °C or 100 °C, and contact time 2 h, 0.5 h, or 0.5 h followed by ambient temperature for 24 h). For reusable stainless-steel sheets, especially for grade 30Cr13, it was essential to perform three consecutive release tests to check compliance. However, there was no need to conduct three consecutive release tests for the other five grades if the results of the first test met the regulations. It was recommended that 5 g L citric acid should be used as food simulant and contact temperature and time should be based on the actual using conditions. No relationships were found between metal release amounts and contact test temperature or time. The specific release limits for Pb, Cr, As, Cd, and Ni should be lowered and Al, Mn, and Fe be added in GB 4806.9. The results of this study can be a reference for further analysis of the release behaviour of metal elements in actual stainless-steel products.
Topics: Alloys; China; Food Analysis; Metals, Heavy; Stainless Steel; Surface Properties
PubMed: 34415827
DOI: 10.1080/19440049.2021.1964700 -
Sensors (Basel, Switzerland) Jul 2022Shape memory materials are smart materials that stand out because of several remarkable properties, including their shape memory effect. Shape memory alloys (SMAs) are... (Review)
Review
Shape memory materials are smart materials that stand out because of several remarkable properties, including their shape memory effect. Shape memory alloys (SMAs) are largely used members of this family and have been innovatively employed in various fields, such as sensors, actuators, robotics, aerospace, civil engineering, and medicine. Many conventional, unconventional, experimental, and numerical methods have been used to study the properties of SMAs, their models, and their different applications. These materials exhibit nonlinear behavior. This fact complicates the use of traditional methods, such as the finite element method, and increases the computing time necessary to adequately model their different possible shapes and usages. Therefore, a promising solution is to develop new methodological approaches based on artificial intelligence (AI) that aims at efficient computation time and accurate results. AI has recently demonstrated some success in efficiently modeling SMA features with machine- and deep-learning methods. Notably, artificial neural networks (ANNs), a subsection of deep learning, have been applied to characterize SMAs. The present review highlights the importance of AI in SMA modeling and introduces the deep connection between ANNs and SMAs in the medical, robotic, engineering, and automation fields. After summarizing the general characteristics of ANNs and SMAs, we analyze various ANN types used for modeling the properties of SMAs according to their shapes, e.g., a wire as an actuator, a wire with a spring bias, wire systems, magnetic and porous materials, bars and rings, and reinforced concrete beams. The description focuses on the techniques used for NN architectures and learning.
Topics: Alloys; Artificial Intelligence; Neural Networks, Computer; Porosity; Shape Memory Alloys
PubMed: 35957170
DOI: 10.3390/s22155610 -
Materials Science & Engineering. C,... Sep 2017Nerve injury, especially the large-size nerve damage, is a serious problem affecting millions of people. Entubulation of two ends of the injured nerve by using an...
Nerve injury, especially the large-size nerve damage, is a serious problem affecting millions of people. Entubulation of two ends of the injured nerve by using an implantable device, e.g., nerve guidance conduit (NGC), to guide the regeneration of nerve tissue is a promising approach for treating the large-size nerve defect. Magnesium (Mg) and its alloys are biodegradable, conductive, and own good mechanical properties. Mg ion, one of the main degradation products of Mg and its alloys, was reported to promote the proliferation of neural stem cells and their neurite production. Thus, Mg and its alloys are potential materials for fabricating the nerve repair implants, such as NGC or scaffold. However, the compatibility of Mg alloys to cells, especially neurons is not clear. In this work, NZ20 (Mg-2Nd-Zn), ZN20 (Mg-2Zn-Nd) and Mg-10Li magnesium alloys were selected for study, due to the improved mechanical properties of NZ20 and ZN20 alloys and bio-function of Li ions from Mg-10Li to nervous system, respectively. The degradation behavior and biocompatibility were studied by in vitro degradation test and cell adhesion assay, respectively. Specifically, the cytocompatibility to dorsal root ganglion (DRG) neurons, RF/6A choroid-retina endothelial cells, and osteoblasts in the cell culture media containing Mg alloy extracts were investigated. The results showed that Mg alloys degraded at different rates in cell culture media and artificial cerebrospinal fluid. The three alloy extracts showed negligible toxic effects on the endothelial cells and osteoblasts at short term (1 day), while NZ20 extract inhibited the proliferation of these two types of cells. The effect of Mg alloy extracts on cell proliferation was also concentration-dependent. For DRG neurons, ZN20 and Mg-10Li alloy extracts showed no neural toxicity compared with control group. The results of the present work show a potential and feasibility of Mg-10Li and ZN20 for nerve repair applications.
Topics: Alloys; Cell Adhesion; Magnesium; Osteoblasts; Prostheses and Implants
PubMed: 28575952
DOI: 10.1016/j.msec.2017.04.106 -
Journal of Orthopaedic Research :... Jun 2022CoCrMo alloys are well-established biomaterials used for orthopedic joint replacement implants. However, such alloys have been associated with clinical problems related...
CoCrMo alloys are well-established biomaterials used for orthopedic joint replacement implants. However, such alloys have been associated with clinical problems related to wear and corrosion. A new generation of austenitic high-nitrogen steels (AHNSs) has been developed for biomedical applications. Here, we have addressed influences of hyaluronic acid, combined with inflammatory (oxidizing) conditions, on tribocorrosion of the high-nitrogen FeCrMnMoN steel (DIN/EN X13CrMnMoN18-14-3, 1.4452), and of the low carbon CoCrMo alloy (ISO 5832-12). We aimed to elucidate critical and clinically relevant conditions affecting the implant's performance in certain orthopedic applications. Tribocorrosion tests were conducted in triplicate, with discs under reciprocating sliding wear against a ceramic ball. Different lubricants were prepared from standardized bovine serum solution (ISO 14242-1), with variable additions of hyaluronic acid (HA) and hydrogen peroxide (H O ). Test conditions were: 37°C, 86,400 cycles, 37 N load (20-40 MPa after run-in phase). Volumetric wear was quantified; surfaces were evaluated by electrochemical parameters and microscopy/spectroscopy analyses (SEM/EDS). Factorial analysis of variance tests was conducted to examine the effects of HA, H O , and test material on wear- and corrosion-related dependent variables. Tribocorrosion performances of CoCrMo and FeCrMnMoN were comparable in fluids without H O . With higher H O concentrations, tribocorrosion increased for CoCrMo , while this was not the case for FeCrMnMoN . HA significantly enhanced wear of CoCrMo in the absence of H O , while it mitigated the tribocorrosive action of 3 mM H O ; HA had no impact on FeCrMnMoN . These results indicate a favorable performance of FeCrMnMoN compared to CoCrMo , and encourage further research on AHNS for certain orthopedic applications.
Topics: Alloys; Corrosion; Hyaluronic Acid; Nickel; Nitrogen; Stainless Steel; Synovial Fluid
PubMed: 34449923
DOI: 10.1002/jor.25174 -
Journal of Biomaterials Applications Nov 2022In this study, Zn-xCu (-0.1 Mg) wires with a diameter of 0.3 mm were obtained by hot extrusion and cold drawing. The microstructures, mechanical properties, and...
In this study, Zn-xCu (-0.1 Mg) wires with a diameter of 0.3 mm were obtained by hot extrusion and cold drawing. The microstructures, mechanical properties, and degradation behaviour were investigated to evaluate their feasibility as biodegradable metals. During the drawing process of the Zn-xCu alloys, many granular CuZn phases were dynamically precipitated, and the grains were significantly refined, along with a significant work softening with the tensile strength decreasing and the elongation increasing (from 161 MPa to 92 MPa and 22%-103% for Zn-0.2Cu). With the increase of Cu additions, the phenomenon of work softening was more intense and there was an opposite trend in the strength changes between the as-extruded rods (increase) and as-drawn wires (decrease). With 0.1 wt.% Mg added, the stable rod-like MgZn phase was formed in as-extruded Zn-xCu-0.1 Mg rods, which obviously improved the strength, and inhibited the dynamic precipitation of granular CuZn phase and work softening phenomenon in the drawing process (from 332 MPa to 313 MPa and 11%-46% for Zn-0.2Cu-0.1 Mg). In addition, due to the micro-galvanic effect induced by the precipitates, alloying accelerated the degradation of Zn alloy wires, especially Zn-1Cu-0.1 Mg, which was related to the shape, distribution, and potential of the phases.
Topics: Alloys; Zinc; Tensile Strength
PubMed: 36032022
DOI: 10.1177/08853282221123934 -
Acta Biomaterialia Feb 2015Due to their biodegradability, magnesium and magnesium-based alloys could represent the third generation of biomaterials. However, their mechanical properties and time... (Review)
Review
Due to their biodegradability, magnesium and magnesium-based alloys could represent the third generation of biomaterials. However, their mechanical properties and time of degradation have to match the needs of applications. Several approaches, such as choice of alloying elements or tailored microstructure, are employed to tailor corrosion behaviour. Due to the high electrochemical activity of Mg, numerous environmental factors (e.g. temperature and surrounding ion composition) influence its corrosion behaviour, making it unpredictable. Nevertheless, the need of reliable in vitro model(s) to predict in vivo implant degradation is increasing. In an attempt to find a correlation between in vitro and vivo corrosion rates, this review presents a systematic literature survey, as well as an attempt to correlate the different results.
Topics: Absorbable Implants; Alloys; Animals; Corrosion; Humans; Magnesium; Models, Biological
PubMed: 25484334
DOI: 10.1016/j.actbio.2014.11.048 -
ACS Biomaterials Science & Engineering Apr 2022Three Zn-based alloys (Zn1Cu, Zn2Cu, and Zn3Cu) were developed by the addition of Cu (1, 2, and 3 wt %) into commercially pure Zn. This report systematically...
Three Zn-based alloys (Zn1Cu, Zn2Cu, and Zn3Cu) were developed by the addition of Cu (1, 2, and 3 wt %) into commercially pure Zn. This report systematically investigates the potential for these newly developed Zn-based alloys as biodegradable materials. Microstructural studies reveal the presence of spherical-shaped nanosized precipitates of ε-CuZn in the Zn1Cu alloy, whereas Zn2Cu and Zn3Cu alloys exhibit the presence of both micron- and nanosized precipitates of ε-CuZn. The mechanical properties such as hardness, tensile and compressive strengths improve significantly with an increase in the amount of Cu in the alloy. The Zn3Cu alloy exhibits the highest yield strength (225 ± 9 MPa) and ultimate tensile strength (330 ± 12 MPa) among all of the alloys, which are ∼2.7 and 2 times higher than those of pure Zn. degradation behavior is evaluated by the potentiodynamic polarization study and immersion testing in Hank's solution for 20 and 75 days. The corrosion rate after both polarization and immersion testing follows the order of pure Zn < Zn1Cu < Zn3Cu < Zn2Cu. An electrochemical impedance spectroscopy (EIS) study also concludes that Zn2Cu shows the lowest corrosion resistance. The % cell viability values of 3T3 fibroblasts cells after 5 days of culture in a 50% diluted extract of pure Zn, Zn2Cu, and Zn3Cu alloys are 76 ± 0.024, 86.18 ± 0.033, and 92.9 ± 0.026%, respectively, establishing the improved cytocompatibility of the alloys as compared to pure Zn. Furthermore, an antibacterial study also reveals that the Zn3Cu alloy exhibits 80, 67, and 100% increases in the zone of inhibition (ZOI) for , , and bacteria, respectively, as compared to that of pure Zn.
Topics: Absorbable Implants; Alloys; Copper; Escherichia coli; Materials Testing; Zinc
PubMed: 35344329
DOI: 10.1021/acsbiomaterials.1c01111 -
Analytical Sciences : the International... Sep 2021Silver or palladium shelled gold nanoparticles were fused into alloy nanoparticles by pulsed-laser irradiation. The alloy nanoparticles could carry antibodies on their...
Silver or palladium shelled gold nanoparticles were fused into alloy nanoparticles by pulsed-laser irradiation. The alloy nanoparticles could carry antibodies on their surfaces without affecting their immune functionalities and interact selectively with antigens on a blotting membrane. Silver or palladium ions desorbed from the alloy nanoparticles as reporter ions upon the UV laser irradiation in a mass spectrometer.
Topics: Alloys; Gold; Gold Alloys; Metal Nanoparticles; Palladium; Silver
PubMed: 33678727
DOI: 10.2116/analsci.21N001 -
Journal of the Mechanical Behavior of... Nov 2018Magnesium alloys as a class of biodegradable metals have great potential to be used as implant materials, which attract much attention. In this review, the mechanical... (Review)
Review
Magnesium alloys as a class of biodegradable metals have great potential to be used as implant materials, which attract much attention. In this review, the mechanical properties of magnesium alloys for medical applications are summarized. The methods to improve the mechanical properties of biodegradable magnesium alloys and the mechanical behaviors of Mg alloys in biomedical application are illustrated. Finally the challenges and future development of biodegradable magnesium alloys are presented.
Topics: Alloys; Biocompatible Materials; Humans; Magnesium; Mechanical Phenomena
PubMed: 30041141
DOI: 10.1016/j.jmbbm.2018.07.022 -
Journal of Biomedical Materials... Jan 2022Iron (Fe) and Fe-based scaffolds have become a research frontier in absorbable materials which is inherent to their promising mechanical properties including fatigue... (Review)
Review
Iron (Fe) and Fe-based scaffolds have become a research frontier in absorbable materials which is inherent to their promising mechanical properties including fatigue strength and ductility. Nevertheless, their slow corrosion rate and low biocompatibility have been their major obstacles to be applied in clinical applications. Over the last decade, various modifications on porous Fe-based scaffolds have been performed to ameliorate both properties encompassing surface coating, microstructural alteration via alloying, and advanced topologically order structural design produced by additive manufacturing (AM) techniques. The recent advent of AM produces topologically ordered porous Fe-based structures with an optimized architecture having controllable pore size and strut thickness, intricate internal design, and larger exposed surface area. This undoubtedly opens up new options for controlling Fe corrosion and its structural strengths. However, the in vitro biocompatibility of the AM porous Fe still needs to be addressed considering its higher corrosion rate due to the larger exposed surface area. This review summarizes the latest progress of the modifications on porous Fe-based scaffolds with a specific focus on their responses on the corrosion behavior and biocompatibility.
Topics: Alloys; Biocompatible Materials; Bone and Bones; Corrosion; Porosity; Tensile Strength
PubMed: 34132457
DOI: 10.1002/jbm.b.34893