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The current performance of biodegradable magnesium-based implants in magnetic resonance imaging:A review

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Bioactive Materials 2021年第12期6卷 4360-4367页

作者： Jonathan espiritu Martin Meier Jan-Marten Seitz Syntellix AG HannoverGermany Hannover Medical School HannoverGermany

Magnesium-based implants are re-emerging as a substantial amendment to standard orthopaedic implants.A brief introduction of magnesium(Mg)as a biodegradable material and basic magnetic resonance imaging(MRI)principles are *** review aims to highlight the current performance of these implants during examinations with *** also aim to summarise comparisons between Mg-based implants with current standards to emphasise the promotion of biodegradable implants in clinical practice.A comprehensive search of current literature on Mg-based implants and the utilisation of MRI in the studies was ***,recorded artefact behaviour of Mg-based implants during MRI was investigated.A total of nine studies were included in which MRI was employed to image Mg-based *** those studies,four of the nine discuss artefact production caused by the *** successfully imaged regions of interest over all and produced fewer artefacts than other materials used in the *** was employed in contrast angiography,bone growth observation,bone infection healing,and blood *** capabilities of an implant material are vital to translating products into clinical *** findings presented in this review suggest and support the use of Mg-based implants due to their successful visual compatibility with MRI techniques.

关键词： Magnetic resonance imaging Magnesium Biodegradable implants Medical imaging Patient safety

Flotation behavior and electronic simulations of rare earth minerals in the presence of dolomite supernatant using sodium oleate collector

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Journal of Rare Earths 2019年第1期37卷 101-112,M0005页

作者： E.R.L.espiritu G.R.da Silva D.Azizi F.Larachi K.E.Waters Department of Mining and Materials Engineering McGill University Department of Chemical Engineering Université Laval

Common rare earth(RE) minerals, such as bastnasite and monazite, may be formed in deposits associated with carbonate gangue, such as calcite and dolomite. Sodium oleate is a widely used collector for the flotation of both RE and gangue minerals, which might, therefore, be an inefficient process due to the lack of selectivity of this collector. Since these minerals are also sparingly soluble in solution, they could release their constituent ions into the solution, which could affect the floatability of other minerals. In this study, the interactions of sodium oleate with bastnasite and monazite in the presence of dissolved dolomite species have been investigated. Microflotation tests were carried out to explore the effects of these dissolved species on the floatability of the RE minerals. Zeta potential measurements and XPS characterization were carried out to understand how the species affect the collector adsorption. To complement these characterizations, density functional theory(DFT) simulations were conducted to investigate the collector-mineral and collector-adsorbed species(on the mineral surface) *** results show that collector-dolomite interaction energy is greater than that of collector-adsorbed species, but lower than collector-monazite interaction energy, explaining the decrease in the minerals' recovery upon exposure to the dissolved mineral species. It is also shown that oleate ions(OI^-) have the strongest interaction with the minerals compared to other oleate species such as acid soap(HOI_2^-) and oleate dimer(OI_2^(2-)). The behavior(strength and selectivity) of sodium oleate towards RE minerals and dolomite, as compared to other RE mineral collectors(such as aromatic hydroxamate), is attributed mainly to the collector's and the minerals' structure. The long hydrocarbon chain of sodium oleate which imparts hydrophobic characteristic to the minerals, makes it stronger collector than ***, sodium oleate(with linear str

关键词： Rare earth minerals Bastnsite Monazite Dolomite Sodium oleate DFT simulation

Detailing the influence of PEO-coated biodegradable Mg-based implants on the lacuno-canalicular network in sheep bone:A pilot study

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Bioactive Materials 2023年第8期26卷 14-23页

作者： Jonathan espiritu Sandra Sefa Hanna Cwieka Imke Greving Silja Flenner Regine Willumeit-Römer Jan-Marten Seitz Berit Zeller-Plumhoff Syntellix AG HannoverGermany Institute of Metallic Biomaterials Helmholtz-Zentrum HereonGeesthachtGermany Institute of Materials Physics Helmholtz-Zentrum HereonGeesthachtGermany

An increasing prevalence of bone-related injuries and aging geriatric populations continue to drive the orthopaedic implant market.A hierarchical analysis of bone remodelling after material implantation is necessary to better understand the relationship between implant and ***,which are housed and communicate through the lacuno-canalicular network(LCN),are integral to bone health and remodelling ***,it is essential to examine the framework of the LCN in response to implant materials or surface *** materials offer an alternative solution to permanent implants,which may require revision or removal *** alloys have resurfaced as promising materials due to their bone-like properties and safe degradation in *** further tailor their degradation capabilities,surface treatments such as plasma electrolytic oxidation(PEO)have demonstrated to slow *** the first time,the influence of a biodegradable material on the LCN is investigated by means of non-destructive 3D *** this pilot study,we hypothesize noticeable variations in the LCN caused by altered chemical stimuli introduced by the *** synchrotron-based transmission X-ray microscopy,we have characterised morphological LCN differences around uncoated and PEO-coated WE43 screws implanted into sheep *** specimens were explanted after 4,8,and 12 weeks and regions near the implant surface were prepared for *** from this investigation indicate that the slower degradation of PEO-coated WE43 induces healthier lacunar shapes within the ***,the stimuli perceived by the uncoated material with higher degradation rates induces a greater connected LCN better prepared for bone disturbance.

关键词： Nanotomography Lacuno-canalicular network Bone Magnesium Biodegradable implants

Multiscale morphological analysis of bone microarchitecture around Mg-10Gd implants

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Bioactive Materials 2023年第12期30卷 154-168页

作者： Sandra Sefa Jonathan espiritu Hanna Cwieka Imke Greving Silja Flenner Olga Will Susanne Beuer D.C Florian Wieland Regine Willumeit-Romer Berit Zeller-Plumhoff Institute of Metallic Biomaterials Helmholtz Zentrum HereonGeesthachtGermany Syntellix AG HannoverGermany Institute of Materials Physics Helmholtz Zentrum HereonGeesthachtGermany Molecular Imaging North Competence Center Kiel UniversityKielGermany Fraunhofer Institut für Integrierte Systeme und Bauelementetechnologie(IISB) ErlangenGermany

The utilization of biodegradable magnesium(Mg)-based implants for restoration of bone function following trauma represents a transformative approach in orthopaedic *** such alloy,magnesium-10 weight percent gadolinium(Mg-10Gd),has been specifically developed to address the rapid degradation of Mg while enhancing its mechanical properties to promote bone *** studies have demonstrated that Mg-10Gd exhibits favorable osseointegration;however,it exhibits distinct ultrastructural adaptation in comparison to conventional implants like titanium(Ti).A crucial aspect that remains unexplored is the impact of Mg-10Gd degradation on the bone *** address this,we employed hierarchical three-dimensional imaging using synchrotron radiation in conjunction with image-based finite element *** using the methods outlined,the vascular porosity,lacunar porosity and the lacunar-canaliculi network(LCN)morphology of bone around Mg-10Gd in comparison to Ti in a rat model from 4 weeks to 20 weeks post-implantation was *** investigation revealed that within our observation period,the degradation of Mg-10Gd implants was associated with significantly lower(p<0.05)lacunar density in the surrounding bone,compared to ***,the LCN morphology and the fluid flow analysis did not significantly differ for both implant *** summary,a more pronounced lower lacunae distribution rather than their morphological changes was detected in the surrounding bone upon the degradation of Mg-10Gd *** implies potential disparities in bone remodelling rates when compared to Ti *** findings shed light on the intricate relationship between Mg-10Gd degradation and bone microarchitecture,contributing to a deeper understanding of the implications for successful osseointegration.

关键词： Biodegradable magnesium implants Lacunar-canalicular network(LCN) Vascular porosity Synchrotron radiation micro computed tomography(SRμCT) Transmission x-ray microscopy(TXM)

Lattice approaches to packed column simulations

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Particuology 2008年第6期6卷 404-411页

作者： richard Caulkin Mike Fairweather richard A. Williams Institute of Particle Science and Engineering School of ProcessEnvironmental and Materials EngineeringUniversity of Leeds

This work presents a review of the findings into the ability of a digitally based particle packing algorithm, called DigiPac, to predict bed structure in a variety of packed columns, for a range of generic pellet shapes frequently used in the chemical and process engineering industries. Resulting macroscopic properties are compared with experimental data derived from both invasive and non-destructive measurement techniques. Additionally, fluid velocity distributions, through samples of the resulting bed structures, are analysed using lattice Boltzmann method （LBM） simulations and are compared against experimental data from the literature.

关键词： Packing algorithm Bed structure Packed columns Macroscopic properties Lattice Boltzmann simulations

Evaluating metallic artefact of biodegradable magnesium-based implants in magnetic resonance imaging

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Bioactive Materials 2022年第9期7卷 382-391页

作者： Jonathan espiritu Mostafa Berangi Christina Yiannakou Eduarda Silva Roberto Francischello Andre Kuehne Thoralf Niendorf Soren Konneker Regine Willumeit-Romer Jan-Marten Seitz Syntellix AG HannoverGermany MRI.TOOLS GmbH BerlinGermany Charit´e-Universitatsmedizin Berlin Corporate Member of Freie Universitat Berlin and Humboldt Universitat zu BerlinBerlinGermany Berlin Ultrahigh Field Facility(B.U.F.F.) Max-Delbrueck Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany Hannover Medical School HannoverGermany Institute of Clinical Physiology National Research CouncilPisaItaly Chemistry and Industrial Chemistry Department Universita di PisaVia Moruzzi 13PisaItaly Fondazione Toscana Gabriele Monasterio Via Moruzzi 1PisaItaly Institute for Materials Research Helmholtz Zentrum HereonGeesthachtGermany

Magnesium(Mg)implants have shown to cause image artefacts or distortions in magnetic resonance imaging(MRI).Yet,there is a lack of information on how the degradation of Mg-based implants influences the image quality of MRI *** this study,Mg-based implants are analysed in vitro,ex vivo,and in the clinical setting for various magnetic field strengths with the aim to quantify metallic artefact *** vitro corroded Mg-based screws and a titanium(Ti)equivalent were imaged according to the ASTM ***-based and Ti pins were also implanted into rat femurs for different time points and scanned to provide insights on the influence of soft and hard tissue on metallic ***,MRI data of patients with scaphoid fractures treated with CE-approved Mg-based compression screws(MAGNEZIX®)were analysed at various time points *** artefact production of the Mg-based material decreased as implant material degraded in all *** worst-case imaging scenario was determined to be when the imaging plane was selected to be perpendicular to the implant ***,the Mg-based implant outperformed the Ti equivalent in all experiments by producing lower metallic artefact(p<0.05).This investigation demonstrates that Mg-based implants generate significantly lower metallic distortion in MRI when compared to *** positive findings suggest and support further research into the application of Mg-based implants including post-operative care facilitated by MRI monitoring of degradation kinetics and bone/tissue healing processes.

关键词： Magnetic resonance imaging Magnesium Biodegradable implants Medical imaging Translational medicine

Expected adult lifespan in tropical trees: Long-term matrix demography in a large plot

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Forest Ecosystems 2022年第4期9卷 558-566页

作者： richard Condit Morton Arboretum 4100 Illinois Rte.53LisleIL60532USA Institute for Marine Sciences University of CaliforniaSanta CruzUSA

Background: Documenting the entire lifetime of long-lived organisms requires splicing together short-term observations. Matrix demography provides a tool to calculate lifetime statistics, but large samples from juvenile to adult are needed, and few such studies have been done in tropical trees because high species diversity limits sample sizes. The 50-ha plot at Barro Colorado in Panama was designed to provide large samples, and with 30years of censuses, accurate population matrices can be ***: In 31 abundant species, I divided all individuals≥1 cm dbh into 4 or 5 size class in each of seven censuses. Movements of stems between size classes over two censuses are termed transitions, and I constructed complete transition matrices for each species. From the matrices, I derived analytic solutions for lifetime demographic statistics. Expected adult lifespan from the sapling stage was the key ***: Expected adult lifespan from the sapling stage varied 100-fold over the 31 species, from 0.5 to 50 years,and maturation time varied from 19 to nearly 200 years. Species with the highest growth rates also had high death rates, and theoretical calculations of reproductive lifespan show that the fast-growing pioneer species have short expected adult lifespans relative to the average slow-growing, shade-tolerant species. Within the slowgrowth category, however, there was high variation in expected adult lifespan, and several shade-tolerant species under-performed the pioneers in terms of adult ***: Analytical solutions from population matrices allow theoretical analyses that integrate short-term growth records into lifespans of tropical trees. The analyses suggest that pioneer species must reproduce more successfully than shade-tolerant species to persist in the Barro Colorado forest. My next goal is to incorporate seed production and germination into lifetime matrix demography to test this hypothesis.

关键词： Tree lifespan Tropical tree Matrix demography

Radiofrequency induced heating of biodegradable orthopaedic screw implants during magnetic resonance imaging

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Bioactive Materials 2023年第7期25卷 86-94页

作者： Jonathan espiritu Mostafa Berangi Hanna Cwieka Kamila Iskhakova Andre Kuehne D.C.Florian Wieland Berit Zeller-Plumhoff Thoralf Niendorf Regine Willumeit-Römer Jan-Marten Seitz Syntellix AG HannoverGermany MRI.TOOLS GmbH BerlinGermany Charité-Universitätsmedizin Berlin Corporate Member of Freie Universität Berlin and Humboldt Universität zu BerlinBerlinGermany Berlin Ultrahigh Field Facility(B.U.F.F.) Max-Delbrueck Center for Molecular Medicine in the Helmholtz AssociationBerlinGermany Institute of Metallic Biomaterials Helmholtz Zentrum HereonGeesthachtGermany

Magnesium(Mg)-based implants have re-emerged in orthopaedic surgery as an alternative to permanent *** reveals little information on how the degradation of biodegradable implants may introduce safety implications for patient follow-up using medical *** resonance imaging(MRI)benefits post-surgery monitoring of bone healing and implantation *** studies demonstrated radiofrequency(RF)heating of permanent implants caused by electromagnetic fields used in *** investigation is the first to report the effect of the degradation layer on RF-induced heating of biodegradable orthopaedic ***43 orthopaedic compression screws underwent in vitro *** techniques were applied to assess the corrosion process and the material composition of the degraded *** measurements were performed to quantify implant heating with respect to the degradation *** comparison,a commercial titanium implant screw was *** RF induced heating was observed for non-degraded WE43 screw *** heating had shown to decrease with the formation of the degradation *** statistical differences were observed for heating of the non-degraded WE43 material and the titanium *** highest risk of implant RF heating is most pronounced for Mg-based screws prior to *** to industry standards for MRI safety assessment is warranted to include biodegradable materials.

关键词： Biodegradable implants Magnesium Medical imaging Magnetic resonance imaging Patient safety

Bound and Resonating Multiquark Configurations

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Chinese Physics Letters 2024年第8期41卷 8-12页

作者： Jean-Marc richard Institut de Physique des 2 Infinis de Lyon Université Claude Bernard(Lyon 1) CNRS-IN2P34 rue Enrico Fermi69622 VilleurbanneFrance

We review the predictions of quark models for multiquark configurations that are bound or resonant states,and compare different methods for estimating the properties of resonances.

关键词： quark Configuration resonant