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BIOTECHNOLOGY (227 journals)                  1 2 | Last

Showing 1 - 200 of 227 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
Advances in Bioscience and Biotechnology     Open Access   (Followers: 14)
Advances in Genetic Engineering & Biotechnology     Hybrid Journal   (Followers: 7)
African Journal of Biotechnology     Open Access   (Followers: 6)
Algal Research     Partially Free   (Followers: 9)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 69)
American Journal of Bioinformatics Research     Open Access   (Followers: 8)
American Journal of Polymer Science     Open Access   (Followers: 30)
Animal Biotechnology     Hybrid Journal   (Followers: 9)
Annales des Sciences Agronomiques     Full-text available via subscription  
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 42)
Applied Bioenergy     Open Access  
Applied Biosafety     Hybrid Journal  
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 62)
Applied Mycology and Biotechnology     Full-text available via subscription   (Followers: 5)
Arthroplasty Today     Open Access   (Followers: 1)
Artificial Cells, Nanomedicine and Biotechnology     Hybrid Journal   (Followers: 2)
Asia Pacific Biotech News     Hybrid Journal   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Pacific Journal of Tropical Biomedicine     Open Access   (Followers: 2)
Australasian Biotechnology     Full-text available via subscription   (Followers: 1)
Banat's Journal of Biotechnology     Open Access  
BBR : Biochemistry and Biotechnology Reports     Open Access   (Followers: 4)
Bio-Algorithms and Med-Systems     Hybrid Journal   (Followers: 1)
Bio-Research     Full-text available via subscription   (Followers: 2)
Bioactive Materials     Open Access   (Followers: 1)
Biocatalysis and Agricultural Biotechnology     Hybrid Journal   (Followers: 4)
Biocybernetics and Biological Engineering     Full-text available via subscription   (Followers: 5)
Bioethics UPdate     Hybrid Journal  
Biofuels     Hybrid Journal   (Followers: 11)
Biofuels Engineering     Open Access   (Followers: 1)
Biological & Pharmaceutical Bulletin     Full-text available via subscription   (Followers: 5)
Biological Cybernetics     Hybrid Journal   (Followers: 10)
Biomarkers and Genomic Medicine     Open Access   (Followers: 5)
Biomarkers in Drug Development     Partially Free   (Followers: 1)
Biomaterials Research     Open Access   (Followers: 4)
BioMed Research International     Open Access   (Followers: 6)
Biomédica     Open Access  
Biomedical Engineering Research     Open Access   (Followers: 7)
Biomedical glasses     Open Access  
Biomedical Reports     Full-text available via subscription  
BioMedicine     Open Access  
Bioprinting     Hybrid Journal  
Bioresource Technology Reports     Hybrid Journal  
Bioscience, Biotechnology, and Biochemistry     Hybrid Journal   (Followers: 22)
Biosimilars     Open Access   (Followers: 1)
Biosurface and Biotribology     Open Access  
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 2)
BioTechniques : The International Journal of Life Science Methods     Full-text available via subscription   (Followers: 28)
Biotechnologia Acta     Open Access   (Followers: 1)
Biotechnologie, Agronomie, Société et Environnement     Open Access   (Followers: 2)
Biotechnology     Open Access   (Followers: 6)
Biotechnology & Biotechnological Equipment     Open Access   (Followers: 5)
Biotechnology Advances     Hybrid Journal   (Followers: 33)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 160)
Biotechnology and Bioprocess Engineering     Hybrid Journal   (Followers: 6)
Biotechnology and Genetic Engineering Reviews     Hybrid Journal   (Followers: 14)
Biotechnology and Health Sciences     Open Access   (Followers: 1)
Biotechnology and Molecular Biology Reviews     Open Access   (Followers: 1)
Biotechnology Annual Review     Full-text available via subscription   (Followers: 7)
Biotechnology for Biofuels     Open Access   (Followers: 10)
Biotechnology Frontier     Open Access   (Followers: 2)
Biotechnology Journal     Hybrid Journal   (Followers: 15)
Biotechnology Law Report     Hybrid Journal   (Followers: 4)
Biotechnology Letters     Hybrid Journal   (Followers: 33)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Biotechnology Reports     Open Access  
Biotechnology Research International     Open Access   (Followers: 2)
Biotechnology Techniques     Hybrid Journal   (Followers: 10)
Biotecnología Aplicada     Open Access  
Biotribology     Hybrid Journal  
BMC Biotechnology     Open Access   (Followers: 15)
Chinese Journal of Agricultural Biotechnology     Full-text available via subscription   (Followers: 3)
Communications in Mathematical Biology and Neuroscience     Open Access  
Computational and Structural Biotechnology Journal     Open Access   (Followers: 2)
Computer Methods and Programs in Biomedicine     Hybrid Journal   (Followers: 8)
Contributions to Tobacco Research     Open Access   (Followers: 3)
Copernican Letters     Open Access   (Followers: 1)
Critical Reviews in Biotechnology     Hybrid Journal   (Followers: 20)
Crop Breeding and Applied Biotechnology     Open Access   (Followers: 4)
Current Bionanotechnology     Hybrid Journal  
Current Biotechnology     Hybrid Journal   (Followers: 3)
Current Opinion in Biomedical Engineering     Hybrid Journal   (Followers: 1)
Current Opinion in Biotechnology     Hybrid Journal   (Followers: 55)
Current Pharmaceutical Biotechnology     Hybrid Journal   (Followers: 9)
Current Research in Bioinformatics     Open Access   (Followers: 14)
Current trends in Biotechnology and Pharmacy     Open Access   (Followers: 9)
EBioMedicine     Open Access  
Electronic Journal of Biotechnology     Open Access   (Followers: 1)
Entomologia Generalis     Full-text available via subscription  
Environmental Science : Processes & Impacts     Full-text available via subscription   (Followers: 4)
Experimental Biology and Medicine     Hybrid Journal   (Followers: 3)
Folia Medica Indonesiana     Open Access  
Food Bioscience     Hybrid Journal  
Food Biotechnology     Hybrid Journal   (Followers: 12)
Food Science and Biotechnology     Hybrid Journal   (Followers: 9)
Frontiers in Bioengineering and Biotechnology     Open Access   (Followers: 6)
Frontiers in Systems Biology     Open Access   (Followers: 2)
Fungal Biology and Biotechnology     Open Access   (Followers: 1)
GM Crops and Food: Biotechnology in Agriculture and the Food Chain     Full-text available via subscription   (Followers: 1)
GSTF Journal of BioSciences     Open Access  
HAYATI Journal of Biosciences     Open Access  
Horticulture, Environment, and Biotechnology     Hybrid Journal   (Followers: 11)
IEEE Transactions on Molecular, Biological and Multi-Scale Communications     Hybrid Journal   (Followers: 1)
IET Nanobiotechnology     Hybrid Journal   (Followers: 2)
IIOAB Letters     Open Access  
IN VIVO     Full-text available via subscription   (Followers: 4)
Indian Journal of Biotechnology (IJBT)     Open Access   (Followers: 2)
Indonesia Journal of Biomedical Science     Open Access   (Followers: 1)
Indonesian Journal of Biotechnology     Open Access   (Followers: 1)
Industrial Biotechnology     Hybrid Journal   (Followers: 18)
International Biomechanics     Open Access  
International Journal of Bioinformatics Research and Applications     Hybrid Journal   (Followers: 15)
International Journal of Biomechatronics and Biomedical Robotics     Hybrid Journal   (Followers: 4)
International Journal of Biomedical Research     Open Access   (Followers: 2)
International Journal of Biotechnology     Hybrid Journal   (Followers: 5)
International Journal of Biotechnology and Molecular Biology Research     Open Access   (Followers: 2)
International Journal of Biotechnology for Wellness Industries     Partially Free   (Followers: 1)
International Journal of Environment, Agriculture and Biotechnology     Open Access   (Followers: 5)
International Journal of Functional Informatics and Personalised Medicine     Hybrid Journal   (Followers: 4)
International Journal of Medicine and Biomedical Research     Open Access   (Followers: 1)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Radiation Biology     Hybrid Journal   (Followers: 4)
Iranian Journal of Biotechnology     Open Access  
ISABB Journal of Biotechnology and Bioinformatics     Open Access  
Italian Journal of Food Science     Open Access   (Followers: 1)
Journal of Biometrics & Biostatistics     Open Access   (Followers: 3)
Journal of Bioterrorism & Biodefense     Open Access   (Followers: 6)
Journal of Petroleum & Environmental Biotechnology     Open Access   (Followers: 2)
Journal of Advanced Therapies and Medical Innovation Sciences     Open Access  
Journal of Advances in Biotechnology     Open Access   (Followers: 5)
Journal Of Agrobiotechnology     Open Access  
Journal of Analytical & Bioanalytical Techniques     Open Access   (Followers: 7)
Journal of Animal Science and Biotechnology     Open Access   (Followers: 6)
Journal of Applied Biomedicine     Open Access   (Followers: 3)
Journal of Applied Biotechnology     Open Access   (Followers: 2)
Journal of Applied Biotechnology Reports     Open Access   (Followers: 2)
Journal of Applied Mathematics & Bioinformatics     Open Access   (Followers: 5)
Journal of Biologically Active Products from Nature     Hybrid Journal   (Followers: 1)
Journal of Biomaterials and Nanobiotechnology     Open Access   (Followers: 6)
Journal of Biomedical Photonics & Engineering     Open Access  
Journal of Biomedical Practitioners     Open Access  
Journal of Bioprocess Engineering and Biorefinery     Full-text available via subscription  
Journal of Bioprocessing & Biotechniques     Open Access  
Journal of Biosecurity, Biosafety and Biodefense Law     Hybrid Journal   (Followers: 3)
Journal of Biotechnology     Hybrid Journal   (Followers: 68)
Journal of Chemical and Biological Interfaces     Full-text available via subscription   (Followers: 1)
Journal of Chemical Technology & Biotechnology     Hybrid Journal   (Followers: 10)
Journal of Chitin and Chitosan Science     Full-text available via subscription  
Journal of Colloid Science and Biotechnology     Full-text available via subscription  
Journal of Commercial Biotechnology     Full-text available via subscription   (Followers: 6)
Journal of Crop Science and Biotechnology     Hybrid Journal   (Followers: 7)
Journal of Essential Oil Research     Hybrid Journal   (Followers: 3)
Journal of Experimental Biology     Full-text available via subscription   (Followers: 25)
Journal of Genetic Engineering and Biotechnology     Open Access   (Followers: 5)
Journal of Ginseng Research     Open Access  
Journal of Industrial Microbiology and Biotechnology     Hybrid Journal   (Followers: 16)
Journal of Integrative Bioinformatics     Open Access  
Journal of International Biotechnology Law     Hybrid Journal   (Followers: 3)
Journal of Medical Imaging and Health Informatics     Full-text available via subscription  
Journal of Molecular Microbiology and Biotechnology     Full-text available via subscription   (Followers: 14)
Journal of Nano Education     Full-text available via subscription  
Journal of Nanobiotechnology     Open Access   (Followers: 4)
Journal of Nanofluids     Full-text available via subscription   (Followers: 2)
Journal of Organic and Biomolecular Simulations     Open Access  
Journal of Plant Biochemistry and Biotechnology     Hybrid Journal   (Followers: 6)
Journal of Science and Applications : Biomedicine     Open Access  
Journal of the Mechanical Behavior of Biomedical Materials     Hybrid Journal   (Followers: 11)
Journal of Trace Elements in Medicine and Biology     Hybrid Journal   (Followers: 1)
Journal of Tropical Microbiology and Biotechnology     Full-text available via subscription  
Journal of Yeast and Fungal Research     Open Access   (Followers: 1)
Marine Biotechnology     Hybrid Journal   (Followers: 5)
Messenger     Full-text available via subscription  
Metabolic Engineering Communications     Open Access   (Followers: 4)
Metalloproteinases In Medicine     Open Access  
Microalgae Biotechnology     Open Access   (Followers: 2)
Microbial Biotechnology     Open Access   (Followers: 9)
MicroMedicine     Open Access   (Followers: 3)
Molecular and Cellular Biomedical Sciences     Open Access  
Molecular Biotechnology     Hybrid Journal   (Followers: 16)
Molecular Genetics and Metabolism Reports     Open Access   (Followers: 3)
Nanobiomedicine     Open Access  
Nanobiotechnology     Hybrid Journal   (Followers: 3)
Nanomaterials and Nanotechnology     Open Access  
Nanomaterials and Tissue Regeneration     Open Access  
Nanomedicine and Nanobiology     Full-text available via subscription  
Nanomedicine Research Journal     Open Access  
Nanotechnology Reviews     Hybrid Journal   (Followers: 5)
Nature Biotechnology     Full-text available via subscription   (Followers: 521)
Network Modeling and Analysis in Health Informatics and Bioinformatics     Hybrid Journal   (Followers: 3)
New Biotechnology     Hybrid Journal   (Followers: 4)
Nigerian Journal of Biotechnology     Open Access  
Nova Biotechnologica et Chimica     Open Access  
NPG Asia Materials     Open Access  
npj Biofilms and Microbiomes     Open Access  
OA Biotechnology     Open Access  
Plant Biotechnology Journal     Open Access   (Followers: 10)
Plant Biotechnology Reports     Hybrid Journal   (Followers: 4)
Preparative Biochemistry and Biotechnology     Hybrid Journal   (Followers: 4)

        1 2 | Last

Journal Cover Journal of the Mechanical Behavior of Biomedical Materials
  [SJR: 1.068]   [H-I: 41]   [11 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1751-6161
   Published by Elsevier Homepage  [3177 journals]
  • High performance resorbable composites for load-bearing bone fixation
    • Authors: Bryant Heimbach; Beril Tonyali; Dianyun Zhang; Mei Wei
      Pages: 1 - 9
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Bryant Heimbach, Beril Tonyali, Dianyun Zhang, Mei Wei
      Bone fractures are some of the most common injuries annually, and many require a fixation device to help properly heal. The present study focuses on developing a bioresorbable composite that has high strength and stiffness for bone fixation applications. To achieve this, a design of experiments was performed, testing the effect of long fiber reinforcement type, matrix type, matrix amount, and particle reinforcement amount on the flexural properties of the composite. Based on these results, the ideal resorbable long fiber reinforcement, particle reinforcement, and matrix material are degummed silk fibroin, hydroxyapatite, and polylactic acid, respectively. Through further optimizations of the particle reinforcement phase a flexural modulus and strength of 13.7 GPa and 437 MPa, respectively, was achieved. Both values are among the highest found in literature, with the strength far exceeding the requirement for a fixation device and the highest for such a bioresorbable composite material, showing great promise for use as a bioresorbable fixation device.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.031
      Issue No: Vol. 81 (2018)
  • Study on titanium-magnesium composites with bicontinuous structure
           fabricated by powder metallurgy and ultrasonic infiltration
    • Authors: S. Jiang; L.J. Huang; Q. An; L. Geng; X.J. Wang; S. Wang
      Pages: 10 - 15
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): S. Jiang, L.J. Huang, Q. An, L. Geng, X.J. Wang, S. Wang
      Titanium-magnesium (Ti-Mg) composites with bicontinuous structure have been successfully fabricated by powder metallurgy and ultrasonic infiltration for biomaterial potential. In the composites, Ti phase is distributed continuously by sintering necks, while Mg phase is also continuous, distributing at the interconnected pores surrounding the Ti phase. The results showed that the fabricated Ti-Mg composites exhibited low modulus and high strength, which are very suitable for load bearing biomedical materials. The composites with 100 µm and 230 µm particle sizes exhibited Young's modulus of 37.6 GPa and 23.4 GPa, 500.7 MPa and 340 MPa of compressive strength and 631.5 MPa and 375.2 MPa of bending strength, respectively. Moreover, both of the modulus and strength of the composites increase with decreasing of Ti particle sizes. In vitro study has been done for the preliminary evaluation of the Ti-Mg composites.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.017
      Issue No: Vol. 81 (2018)
  • Strength and fracture mechanism of iron reinforced tricalcium phosphate
           cermet fabricated by spark plasma sintering
    • Authors: Serhii Tkachenko; Miroslava Horynová; Mariano Casas-Luna; Sebastian Diaz-de-la-Torre; Karel Dvořák; Ladislav Celko; Jozef Kaiser; Edgar B. Montufar
      Pages: 16 - 25
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Serhii Tkachenko, Miroslava Horynová, Mariano Casas-Luna, Sebastian Diaz-de-la-Torre, Karel Dvořák, Ladislav Celko, Jozef Kaiser, Edgar B. Montufar
      The present work studies the microstructure and mechanical performance of tricalcium phosphate (TCP) based cermet toughened by iron particles. A novelty arises by the employment of spark plasma sintering for fabrication of the cermet. Results showed partial transformation of initial alpha TCP matrix to beta phase and the absence of oxidation of iron particles, as well as a lack of chemical reaction between TCP and iron components during sintering. The values of compressive and tensile strength of TCP/Fe cermet were 3.2 and 2.5 times, respectively, greater than those of monolithic TCP. Fracture analysis revealed the simultaneous action of crack-bridging and crack-deflection microstructural toughening mechanisms under compression. In contrast, under tension the reinforcing mechanism was only crack-bridging, being the reason for smaller increment of strength. Elastic properties of the cermet better matched values reported for human cortical bone. Thereby the new TCP/Fe cermet has potential for eventual use as a material for bone fractures fixation under load-bearing conditions.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.016
      Issue No: Vol. 81 (2018)
  • Titanium surface bio-functionalization using osteogenic peptides: Surface
           chemistry, biocompatibility, corrosion and tribocorrosion aspects
    • Authors: Luciana D. Trino; Erika S. Bronze-Uhle; Amsaveni Ramachandran; Paulo N. Lisboa-Filho; Mathew T. Mathew; Anne George
      Pages: 26 - 38
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Luciana D. Trino, Erika S. Bronze-Uhle, Amsaveni Ramachandran, Paulo N. Lisboa-Filho, Mathew T. Mathew, Anne George
      Titanium (Ti) is widely used in biomedical devices due to its recognized biocompatibility. However, implant failures and subsequent clinical side effects are still recurrent. In this context, improvements can be achieved by designing biomaterials where the bulk and the surface of Ti are independently tailored. The conjugation of biomolecules onto the Ti surface can improve its bioactivity, thus accelerating the osteointegration process. Ti was modified with TiO2, two different spacers, 3-(4-aminophenyl) propionic acid (APPA) or 3-mercaptopropionic acid (MPA) and dentin matrix protein 1 (DMP1) peptides. X-ray photoelectron spectroscopy analysis revealed the presence of carbon and nitrogen for all samples, indicating a success in the functionalization process. Furthermore, DMP1 peptides showed an improved coverage area for the samples with APPA and MPA spacers. Biological tests indicated that the peptides could modulate cell affinity, proliferation, and differentiation. Enhanced results were observed in the presence of MPA. Moreover, the immobilization of DMP1 peptides through the spacers led to the formation of calcium phosphate minerals with a Ca/P ratio near to that of hydroxyapatite. Corrosion and tribocorrosion results indicated an increased resistance to corrosion and lower mass loss in the functionalized materials, showing that this new type of functional material has attractive properties for biomaterials application.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.024
      Issue No: Vol. 81 (2018)
  • The impact of shape memory test on degradation profile of a bioresorbable
    • Authors: Marta Musioł; Sebastian Jurczyk; Michał Kwiecień; Anna Smola-Dmochowska; Marian Domański; Henryk Janeczek; Jakub Włodarczyk; Magdalena Klim; Joanna Rydz; Michał Kawalec; Michał Sobota
      Pages: 39 - 45
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Marta Musioł, Sebastian Jurczyk, Michał Kwiecień, Anna Smola-Dmochowska, Marian Domański, Henryk Janeczek, Jakub Włodarczyk, Magdalena Klim, Joanna Rydz, Michał Kawalec, Michał Sobota
      The semicrystalline poly(L-lactide) (PLLA) belongs to the materials with shape memory effect (SME) and as a bioresorbable and biocompatible polymer it have found many applications in medical and pharmaceutical field. Assessment of the SME impact on the polymer degradation profile plays crucial role in applications such as drug release systems or in regenerative medicine. Herein, the results of in vitro degradation studies of PLLA samples after SME full test cycle are presented. The samples were loaded and deformed in two manners: progressive and non-progressive. The performed experiments illustrate also influence of the material mechanical damages, caused e.g. during incorrect implantation of PLLA product, on hydrolytic degradation profile. Apparently, degradation profiles are significantly different for the material which was not subjected to the deformation and the deformed ones. The materials after deformation of 50% (in SME cycle) was characterized by non-reversible morphology changes. The effect was observed in deformed samples during the SME test which were carried out ten times.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.020
      Issue No: Vol. 81 (2018)
  • On the stability efficiency of anchorage self-tapping screws: Ex vivo
           experiments on miniscrew implants used in orthodontics
    • Authors: Marco Migliorati; Sara Drago; Domenico Dalessandri; Alberto Lagazzo; Fabio Gallo; Marco Capurro; Armando Silvestrini-Biavati
      Pages: 46 - 51
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Marco Migliorati, Sara Drago, Domenico Dalessandri, Alberto Lagazzo, Fabio Gallo, Marco Capurro, Armando Silvestrini-Biavati
      Background The clinical success of orthodontic miniscrews is strictly related to primary stability, which depends on bone viscoelastic properties too. In this study, we evaluated the short time mechanical response of native bone to miniscrews, by a laboratory test based on dynamic loading. Methods Thirty-six segments of porcine ribs were first scanned by cone-beam computerized tomography to obtain insertion-site cortical thickness, cortical and marrow bone density. Twelve different types of miniscrews were implanted in the bone samples to evaluate the elastic compliance of the implants in response to a point force applied at the screw head normally to the screw axis. The compliance was measured dynamically in a Dynamic Mechanical Analysis apparatus as the Fourier Response Function between the signals of displacement and force. The measurements were repeated in five days successive to the insertion of the miniscrew. Findings The elastic compliance was positively related to observation timepoints, but it was not related neither to the screw type nor to the value of the insertion torque. Interpretation Stability behavior is significantly related to the short time response of native bone rather than to the screw design or the insertion torque values.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.019
      Issue No: Vol. 81 (2018)
  • Effects of crystal refining on wear behaviors and mechanical properties of
           lithium disilicate glass-ceramics
    • Authors: Zhenzhen Zhang; Jiawen Guo; Yali Sun; Beimin Tian; Xiaojuan Zheng; Ming Zhou; Lin He; Shaofeng Zhang
      Pages: 52 - 60
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Zhenzhen Zhang, Jiawen Guo, Yali Sun, Beimin Tian, Xiaojuan Zheng, Ming Zhou, Lin He, Shaofeng Zhang
      Objectives The purpose of this study is to improve wear resistance and mechanical properties of lithium disilicate glass-ceramics by refining their crystal sizes. Methods After lithium disilicate glass-ceramics (LD) were melted to form precursory glass blocks, bar (N = 40, n = 10) and plate (N = 32, n = 8) specimens were prepared. According to the differential scanning calorimetry (DSC) of precursory glass, specimens G1–G4 were designed to form lithium disilicate glass-ceramics with different crystal sizes using a two-step thermal treatment. In the meantime, heat-pressed lithium disilicate glass-ceramics (GC-P) and original ingots (GC-O) were used as control groups. Glass-ceramics were characterized using X-ray diffraction (XRD) and were tested using flexural strength test, nanoindentation test and toughness measurements. The plate specimens were dynamically loaded in a chewing simulator with 350 N up to 2.4 × 106 loading cycles. The wear analysis of glass-ceramics was performed using a 3D profilometer after every 300,000 wear cycles. Wear morphologies and microstructures were analyzed by scanning electron microscopy (SEM). One-way analysis of variance (ANOVA) was used to analyze the data. Multiple pairwise comparisons of means were performed by Tukey's post-hoc test. Results Materials with different crystal sizes (p < 0.05) exhibited different properties. Specifically, G3 with medium-sized crystals presented the highest flexural strength, hardness, elastic modulus and fracture toughness. G1 and G2 with small-sized crystals showed lower flexural strength, whereas G4, GC-P, and GC-O with large-sized crystals exhibited lower hardness and elastic modulus. The wear behaviors of all six groups showed running-in wear stage and steady wear stage. G3 showed the best wear resistance while GC-P and GC-O exhibited the highest wear volume loss. Conclusions After crystal refining, lithium disilicate glass-ceramic with medium-sized crystals showed the highest wear resistance and mechanical properties.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.023
      Issue No: Vol. 81 (2018)
  • Reinforcing effect of graphene oxide reinforcement on the properties of
           poly (vinyl alcohol) and carboxymethyl tamarind gum based phase-separated
    • Authors: Indu Yadav; Suraj K. Nayak; V.S. Sharan Rathnam; Indranil Banerjee; Sirsendu S. Ray; Arfat Anis; Kunal Pal
      Pages: 61 - 71
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Indu Yadav, Suraj K. Nayak, V.S. Sharan Rathnam, Indranil Banerjee, Sirsendu S. Ray, Arfat Anis, Kunal Pal
      The current study deals with the preparation and the characterization of the PVA-CMT-GO films. The PVA-CMT film was translucent in nature and smooth to touch. The addition of GO resulted in the formation of agglomerated structures. XRD studies suggested that the incorporation of GO increased the average crystallite size. The mechanical properties of the films as determined by stress relaxation studies suggested that all the films were viscoelastic in nature. The drug release study showed a decrease in the amount of the drug release with the increase in the GO content. The PVA-CMT-GO films (without drug) showed certain degree of antimicrobial activity owing to the inherent antimicrobial property of GO. The drug loaded films also showed good antimicrobial property. It was found that the prepared films altered the cell proliferation of the human skin keratinocytes in a composition-dependent manner.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.021
      Issue No: Vol. 81 (2018)
  • Simulating damage onset and evolution in fully bio-resorbable composite
           under three-point bending
    • Authors: Xi Gao; Menghao Chen; Xiaogang Yang; Lee Harper; Ifty Ahmed; Jiawa Lu
      Pages: 72 - 82
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Xi Gao, Menghao Chen, Xiaogang Yang, Lee Harper, Ifty Ahmed, Jiawa Lu
      This paper presents a strain-based damage model to predict the stress-strain relationship and investigate the damage onset and evolution of the fibre and matrix of a fully bio-resorbable phosphate glass fibre reinforced composite under three-point bending. The flexural properties of the composite are crucial, particularly when it is employed as implant for long bone fracture. In the model, the 3D case of the strain and stress was used and the response of the undamaged material was assumed to be linearly elastic. The onset of damage was indicated by two damage variables for the fibre and matrix, respectively. The damage evolution law was based on the damage variable and the facture energy of the fibre and matrix, individually. A finite element (FE) model was created to implement the constitutive model and conduct numerical tests. An auto-adaptive algorithm is integrated in the FE model to improve the convergence. The FE model was capable of predicting the flexural modulus with around 3% relative error, and the flexural strength within 2% relative error in comparison with the experimental data. The numerical indices showed that the top surface of the sample was the most vulnerable under three-point bending. It was also found that the damage initiated in the fibre, was the primary driver for composite failure under three-point bending.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.022
      Issue No: Vol. 81 (2018)
  • A new mechanical indentation framework for functional assessment of
           articular cartilage
    • Authors: Zohreh Arabshahi; Isaac Oluwaseun Afara; Hayley Ruscoe Moody; Karsten Schrobback; Jamal Kashani; Nadine Fischer; Adekunle Oloyede; Travis Jacob Klein
      Pages: 83 - 94
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Zohreh Arabshahi, Isaac Oluwaseun Afara, Hayley Ruscoe Moody, Karsten Schrobback, Jamal Kashani, Nadine Fischer, Adekunle Oloyede, Travis Jacob Klein
      The conventional mechanical properties of articular cartilage, such as compressive stiffness, have been shown to have limited capacity to distinguish visually normal from degraded cartilage samples. In this study, a new mechanical indentation framework for assessing functional properties of articular cartilage during loading/unloading, i.e. deformation and recovery, was established. The capacity of a ring-shaped indenter integrated with an ultrasound transducer to distinguish mechanically intact from proteoglycan-depleted tissue was investigated. To achieve this, normal and enzymatically degraded bovine osteochondral samples were subjected to loading/unloading while the response of the tissue at the middle was captured by ultrasound at the same time. The enzymatic degradation model was characterized by amount of proteoglycan content, glycosaminoglycan release and proteomic analysis. The mechanical response of a wider continuum of articular cartilage in the loaded area and its surrounding region was captured in this framework leading to investigate two parameters, L and TS, related to the surrounding tissue of the loaded area for functional assessment of cartilage. L is the distance between the ultrasound transducer and articular cartilage surface and TS is the transient strain of articular cartilage during loading and unloading. Classification Analysis based on Principal Component Analysis was used to investigate the capacity of the new parameters to assess the functionality of the tissue. Multivariate statistics based on Partial Least Squares regression was employed to identify the correlation between the response of the tissue in the indented area and its surrounding cartilage. The results of this study indicate that L during loading (deformation) can differentiate normal and mildly proteoglycan-depleted samples from severely depleted samples and L during unloading (recovery) can distinguish between normal and proteoglycan-depleted tissue. However, TS during deformation and recovery is unable to discriminate normal cartilage samples from proteoglycan-depleted tissue. The results also demonstrate a strong correlation between mechanical properties of the loaded area with the response of its surrounding cartilage during recovery. It is therefore concluded that L in this newly established framework can discriminate between normal and proteoglycan-depleted cartilage samples. However, more samples will be needed to verify the demarcation between samples degraded for varying amount of time.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.028
      Issue No: Vol. 81 (2018)
  • Optimization simulated injection molding process for ultrahigh molecular
           weight polyethylene nanocomposite hip liner using response surface
           methodology and simulation of mechanical behavior
    • Authors: Behzad Shiroud Heidari; Seyed Mohammad Davachi; Amin Hedayati Moghaddam; Javad Seyfi; Iman Hejazi; Razi Sahraeian; Hamid Rashedi
      Pages: 95 - 105
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Behzad Shiroud Heidari, Seyed Mohammad Davachi, Amin Hedayati Moghaddam, Javad Seyfi, Iman Hejazi, Razi Sahraeian, Hamid Rashedi
      In this study, injection molding process of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with nano-hydroxyapatite (nHA) was simulated and optimized through minimizing the shrinkage and warpage of the hip liners as an essential part of a hip prosthesis. Fractional factorial design (FFD) was applied to the design of the experiment, modeling, and optimizing the shrinkage and warpage of UHMWPE/nHA composite liners. The Analysis of variance (ANOVA) was applied to find the importance of operative parameters and their effects. In this experiment, seven input parameters were surveyed, including mold temperature (A), melt temperature (B), injection time (C), packing time (D), packing pressure (E), coolant temperature (F), and type of liner (G). Two models were capable of predicting warpage and volumetric shrinkage (%) in different conditions with R2 of 0.9949 and 0.9989, respectively. According to the models, the optimized values of warpage and volumetric shrinkage are 0.287222 mm and 13.6613%, respectively. Meanwhile, a finite element analysis (FE analysis) was also carried out to examine the stress distribution in liners under the force values of demanding and daily activities. The Von-Mises stress distribution showed that both of the liners can be applied to all activities with no failure. However, UHMWPE/nHA liner is more resistant to the highest loads than UHMWPE liner due to the effect of nHA in the nanocomposite. Finally, according to the results of injection molding simulations, optimization, structural analysis as well as the tensile strength and wear resistance, UHMWPE/nHA liner is recommended for the production of a hip prosthesis.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.025
      Issue No: Vol. 81 (2018)
  • Impact response and energy absorption of human skull cellular bones
    • Authors: Qianqian Wu; Li Ma; Qiunan Liu; Lina Feng; Zhenyu Wang; Arne Ohrndorf; Hans-Jürgen Christ; Jian Xiong
      Pages: 106 - 119
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Qianqian Wu, Li Ma, Qiunan Liu, Lina Feng, Zhenyu Wang, Arne Ohrndorf, Hans-Jürgen Christ, Jian Xiong
      A skull fracture, due to a composition of typical lightweight cellular structures, is the most common type of traumatic brain injury. This paper presents a systematic investigation on the failure mechanism and energy absorption of skull cellular bones under low- and medium-velocity impact loadings. Non-destructive three-dimensional micro-computed tomography (Micro-CT) is utilized to scan samples of human skull cellular bones, and relevant structural parameters are obtained to reconstruct a finite element (FE) model of these bones. Micro-structures, mechanical properties, and failure process analysis of human skull cellular bones under impact loadings are investigated. The effects of some typical parameters, such as impact velocity and angle, impactor shape and density, and various reconstructed sections on the impact behavior of human skull cellular bones are investigated. Their impact properties and energy absorption are summarized. The present work will be of great significance in understanding the mechanical mystery of human skull cellular bones under impact loading.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.018
      Issue No: Vol. 81 (2018)
  • Enhanced lubricant film formation through micro-dimpled hard-on-hard
           artificial hip joint: An in-situ observation of dimple shape effects
    • Authors: Dipankar Choudhury; David Rebenda; Shinya Sasaki; Pavel Hekrle; Martin Vrbka; Min Zou
      Pages: 120 - 129
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Dipankar Choudhury, David Rebenda, Shinya Sasaki, Pavel Hekrle, Martin Vrbka, Min Zou
      This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20–50 µm lateral size and 1 ± 0.2 µm depths were fabricated on CrCoMo hip joint femoral heads using a picosecond laser. Tribological studies were performed using a pendulum hip joint simulator to apply continuous swing flexion–extension motions. The results revealed a significantly enhanced lubricant film thickness (≥ 500 nm) with micro-dimpled prosthesis heads at equilibrium position after the lubricant film has fully developed. The average lubricant film thickness of dimpled prostheses with square- and triangular-shaped dimple arrays over time is about 3.5 that of the non-dimpled prosthesis (204 nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5 s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4 s. The fully developed lubricant film thicknesses (≥ 700 nm) are significantly higher than the surface roughness (≈ 25 nm) demonstrating a hydrodynamic lubrication. Hardly any scratches appeared on the post-experimental prosthesis with square-shaped dimple array and only a few scratches were found on the post-experimental prosthesis with triangular-shaped dimple arrays. Thus, prostheses with square-shaped dimple arrays could be a potential solution for durable artificial hip joints.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.014
      Issue No: Vol. 81 (2018)
  • Effect of Cu on microstructure, mechanical properties, corrosion
           resistance and cytotoxicity of CoCrW alloy fabricated by selective laser
    • Authors: Yanjin Lu; Ling Ren; Xiongcheng Xu; Yang Yang; Songquan Wu; Jiasi Luo; Mingyu Yang; Lingling Liu; Danhong Zhuang; Ke Yang; Jinxin Lin
      Pages: 130 - 141
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Yanjin Lu, Ling Ren, Xiongcheng Xu, Yang Yang, Songquan Wu, Jiasi Luo, Mingyu Yang, Lingling Liu, Danhong Zhuang, Ke Yang, Jinxin Lin
      In the study, CoCrWCu alloys with differing Cu content (2, 3, 4 wt%) were prepared by selective laser melting using mixture powders consisting of CoCrW and Cu, aiming at investigating the effect of Cu on the microstructures, mechanical properties, corrosion behavior and cytotoxicity. The SEM observations indicated that the Cu content up to 3 wt% caused the Si-rich precipitates to segregate along grain boundaries and in the grains, and EBSD analysis suggested that the Cu addition decreased the recrystallization degree and increased the grain diameter and fraction of big grains. The tensile tests found that the increasing Cu content led to a decrease of mechanical properties compared with Cu-free CoCrW alloy. The electrochemical tests revealed that the addition of Cu shifted the corrosion potential toward nobler positive, but increased the corrosion current density. Also, a more protective passive film was formed when 2 wt% Cu content was added, but the higher Cu content up to 3 wt% was detrimental to the corrosion resistance. It was noted that there was no cytotoxicity for Cu-bearing CoCrW alloys to MG-63 cell and the cells could spread well on the surfaces of studied alloys. Meanwhile, the Cu-bearing CoCrW alloy exhibited an excellent antibacterial performance against E.coli when Cu content was up to 3 wt%. It is suggested that the feasible fabrication of Cu-bearing CoCrW alloy by SLM using mixed CoCrW and Cu powders is a promising candidate for use in antibacterial oral repair products. This current study also can aid in the further design of antibacterial Cu-containing CoCrW alloying powders.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.026
      Issue No: Vol. 81 (2018)
  • Preparation and biocompatibility evaluation of polypropylene mesh coated
           with electrospinning membrane for pelvic defects repair
    • Authors: Yao Lu; Shaoju Fu; Shuanglin Zhou; Ge Chen; Chaoting Zhu; Nannan Li; Ying Ma
      Pages: 142 - 148
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Yao Lu, Shaoju Fu, Shuanglin Zhou, Ge Chen, Chaoting Zhu, Nannan Li, Ying Ma
      Composite mesh with different materials composition could compensate for the drawbacks brought by single component mesh. Coating a membrane layer on the surface of macroporous mesh is a common method for preparing composite medical mesh. Electrospinning and dipping methods were introduced to form the two kinds of membrane-coated PP meshes (electro-mesh and dip-mesh); several properties were measured based on subcutaneous implantation model in rat. The results revealed that continuous tissue ingrowth could be observed for electro-mesh only with evidences of strength increase (electro-mesh: 0 week − 13.1 ± 0.88 N, 2 week − 16.87 ± 1.39 N, 4 week − 22.04 ± 2.05 N) and thickness increase (electro-mesh: 0 week − 0.437 ± 0.023 mm, 2 week − 0.488 ± 0.025 mm, 4 week − 0.576 ± 0.028 mm). However, no tissues were observed for dip-mesh in the first 2 weeks, both on macroscopic level and microscopic level, proved by strength data (dip-mesh: 0 week − 13.36 ± 1.06 N, 2 week − 13.4 ± 1.33 N, 4 week – 18.61 ± 1.89 N) and thickness data (dip-mesh: 0 week − 0.439 ± 0.018 mm, 2 week − 0.439 ± 0.019 mm, 4 week − 0.502 ± 0.032 mm). Electro-mesh had larger surface area decrease (10.74 ± 1.22%) than that of dip-mesh (2.78 ± 0.52%). The adhesion level of electro-mesh (medium adhesion) was also higher than that of dip-mesh (mild adhesion). Even if showing differences in several properties, both meshes were similar under histological observation, with the ability to support fresh tissues ingrowth. Considering operation environment, electro-mesh seems more suitable than dip-mesh with a rapid tissue growing, medium adhesion rate for repairing pelvic floor defects.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.030
      Issue No: Vol. 81 (2018)
  • An analysis of crack growth in dentin at the microstructural scale
    • Authors: Bingbing An; Dongsheng Zhang
      Pages: 149 - 160
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Bingbing An, Dongsheng Zhang
      Dentin is a biocomposite possessing complex hierarchical structure, which endows this hard tissue with excellent damage tolerance. In this study, crack growth in dentin at the microstructural scale is investigated and the synergistic effects of plastic deformation of intertubular dentin (ITD), elasticity and fracture properties of peritubular dentin (PTD), and fracture properties of PTD/ITD interface on the fracture of dentin are explored. A micromechanical model is developed, which captures the experimentally observed fracture process of dentin, i.e. occurrence of microcracking of PTD ahead of the main crack. It is found through numerical simulations that high relative stiffness and low cohesive strength of PTD increase the propensity of microcracking of PTD, whereas reduce the plastic dissipation and toughness of the microstructure of dentin. The microcracking of PTD can be also promoted by low toughness of PTD. The large friction angle and weak strain hardening of ITD could promote the microcracking of PTD, and simultaneously enhance the toughness of the microstructure of dentin. In addition, it is identified that the cohesive strength of the PTD/ITD interface plays a crucial role in dominating fracture mechanisms; low cohesive strength leads to fracture of interface and suppresses microcracking of PTD, which provides an explanation for the crack deflection along interface observed in experiments. Nevertheless, the toughness of interface has a negligible influence on the fracture of dentin.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.029
      Issue No: Vol. 81 (2018)
  • Effects of sterilization on the mechanical properties of poly(methyl
           methacrylate) based personalized medical devices
    • Authors: T.J.A.G. Münker; S.E.C.M. van de Vijfeijken; C.S. Mulder; V. Vespasiano; A.G. Becking; C.J. Kleverlaan; A.G. Becking; L. Dubois; L.H.E. Karssemakers; D.M.J. Milstein; S.E.C.M. van de Vijfeijken; P.R.A.M. Depauw; F.W.A. Hoefnagels; W.P. Vandertop; C.J. Kleverlaan; T.J.A.G. Münker; T.J.J. Maal; E. Nout; M. Riool; S.A.J. Zaat
      Pages: 168 - 172
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): T.J.A.G. Münker, S.E.C.M. van de Vijfeijken, C.S. Mulder, V. Vespasiano, A.G. Becking, C.J. Kleverlaan, A.G. Becking, L. Dubois, L.H.E. Karssemakers, D.M.J. Milstein, S.E.C.M. van de Vijfeijken, P.R.A.M. Depauw, F.W.A. Hoefnagels, W.P. Vandertop, C.J. Kleverlaan, T.J.A.G. Münker, T.J.J. Maal, E. Nout, M. Riool, S.A.J. Zaat
      Background Nowadays, personalized medical devices are frequently used for patients. Due to the manufacturing procedure sterilization is required. How different sterilization methods affect the mechanical behavior of these devices is largely unknown. Materials and methods Three poly(methyl methacrylate) (PMMA) based materials (Vertex Self-Curing, Palacos R+G, and NextDent C&B MFH) were sterilized with different sterilization methods: ethylene oxide, hydrogen peroxide gas plasma, autoclavation, and γ-irradiation. Mechanical properties were determined by testing the flexural strength, flexural modulus, fracture toughness, and impact strength. Results The flexural strength of all materials was significantly higher after γ-irradiation compared to the control and other sterilization methods, as tested in a wet environment. NextDent C&B MFH showed the highest flexural and impact strength, Palacos R+G showed the highest maximum stress intensity factor and total fracture work. Conclusion Autoclave sterilization is not suitable for the sterilization of PMMA-based materials. Ethylene oxide, hydrogen peroxide gas plasma, and γ-irradiation appear to be suitable techniques to sterilize PMMA-based personalized medical devices.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.033
      Issue No: Vol. 81 (2018)
  • Effect of fatigue protocols on flexural strength of lithium disilicate
           bars with clamped-ends
    • Authors: Aline Serrado de Pinho Barcellos; Caroline Cotes Marinho; Jean Soares Miranda; Marina Amaral; Marcos Yutaka Shiino; Estevão Tomomitsu Kimpara
      Pages: 173 - 177
      Abstract: Publication date: May 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 81
      Author(s): Aline Serrado de Pinho Barcellos, Caroline Cotes Marinho, Jean Soares Miranda, Marina Amaral, Marcos Yutaka Shiino, Estevão Tomomitsu Kimpara
      The aim of this study was compare the effect of two in vitro ageing protocols to intraoral aging on the flexural strength of a lithium disilicate (LD) ceramic bars with clamped ends. After polishing and crystallization, the both ends of the bars were cemented to a metallic device and subjected to mechanical cycling, thermomechanical cycling, or intraoral ageing. Ten volunteers used an intraoral device - similar to an occlusal splint with a balanced contact condition on the occlusal surface of the ceramic bar - during 8 h night time / 30 days. Both in vitro and intraoral ageing decreased the flexural residual strength of LD, with the lowest values obtained after intraoral ageing. Thus, the in vitro ageing protocols tested in this study revealed to be less deleterious than intraoral ageing of LD.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.007
      Issue No: Vol. 81 (2018)
  • A novel approach to determine primary stability of acetabular press-fit
    • Authors: Volker Weißmann; Christian Boss; Rainer Bader; Harald Hansmann
      Pages: 1 - 10
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Volker Weißmann, Christian Boss, Rainer Bader, Harald Hansmann
      Today hip cups are used in a large variety of design variants and in increasing numbers of units. Their development is steadily progressing. In addition to conventional manufacturing methods for hip cups, additive methods, in particular, play an increasingly important role as development progresses. The present paper describes a modified cup model developed based on a commercially available press-fit cup (Allofit 54/JJ). The press-fit cup was designed in two variants and manufactured using selective laser melting (SLM). Variant 1 (Ti) was modeled on the Allofit cup using an adapted process technology. Variant 2 (Ti-S) was provided with a porous load bearing structure on its surface. In addition to the typical (complete) geometry, both variants were also manufactured and tested in a reduced shape where only the press-fit area was formed. To assess the primary stability of the press-fit cups in the artificial bone cavity, pull-out and lever-out tests were carried out. Exact fit conditions and two-millimeter press-fit were investigated. The closed-cell PU foam used as an artificial bone cavity was mechanically characterized to exclude any influence on the results of the investigation. The pull-out forces of the Ti-variant (complete-526 N, reduced-468 N) and the Ti-S variant (complete-548 N, reduced-526 N) as well as the lever-out moments of the Ti-variant (complete-10 Nm, reduced–9.8 Nm) and the Ti-S variant (complete-9 Nm, reduced–7.9 N) show no significant differences in the results between complete and reduced cups. The results show that the use of reduced cups in a press-fit design is possible within the scope of development work.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.015
      Issue No: Vol. 80 (2018)
  • Preparation and characterization of silane-modified SiO2 particles
           reinforced resin composites with fluorinated acrylate polymer
    • Authors: Xue Liu; Zengyao Wang; Chengji Zhao; Wenhuan Bu; Hui Na
      Pages: 11 - 19
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Xue Liu, Zengyao Wang, Chengji Zhao, Wenhuan Bu, Hui Na
      A series of fluorinated dental resin composites were prepared with two kinds of SiO2 particles. Bis-GMA (bisphenol A-glycerolate dimethacrylate)/4-TF-PQEA (fluorinated acrylate monomer)/TEGDMA (triethylene glycol dimethacrylate) (40/30/30, wt/wt/wt) was introduced as resin matrix. SiO2 nanopartices (30nm) and SiO2 microparticles (0.3µm) were silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) and used as fillers. After mixing the resin matrix with 0%, 10%, 20%, 30% SiO2 nanopartices and 0%, 10%, 20%, 30%, 40%, 50% SiO2 microparticles, respectively, the fluorinated resin composites were obtained. Properties including double bond conversion (DC), polymerization shrinkage (PS), water sorption (Wp), water solubility (Wy), mechanical properties and cytotoxicity were investigated in comparison with those of neat resin system. The results showed that, filler particles could improve the overall performance of resin composites, particularly in improving mechanical properties and reducing PS of composites along with the addition of filler loading. Compared to resin composites containing SiO2 microparticles, SiO2 nanoparticles resin composites had higher DC, higher mechanical properties, lower PS and lower Wp under the same filler content. Especially, 50% SiO2 microparticles reinforced resins exhibited the best flexural strength (104.04 ± 7.40MPa), flexural modulus (5.62 ± 0.16GPa), vickers microhardness (37.34 ± 1.13 HV), compressive strength (301.54 ± 5.66MPa) and the lowest polymerization (3.42 ± 0.22%).

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.004
      Issue No: Vol. 80 (2018)
  • Assessing women's lacrosse head impacts using finite element modelling
    • Authors: J. Michio Clark; T. Blaine Hoshizaki; Michael D. Gilchrist
      Pages: 20 - 26
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): J. Michio Clark, T. Blaine Hoshizaki, Michael D. Gilchrist
      Recently studies have assessed the ability of helmets to reduce peak linear and rotational acceleration for women's lacrosse head impacts. However, such measures have had low correlation with injury. Maximum principal strain interprets loading curves which provide better injury prediction than peak linear and rotational acceleration, especially in compliant situations which create low magnitude accelerations but long impact durations. The purpose of this study was to assess head and helmet impacts in women's lacrosse using finite element modelling. Linear and rotational acceleration loading curves from women's lacrosse impacts to a helmeted and an unhelmeted Hybrid III headform were input into the University College Dublin Brain Trauma Model. The finite element model was used to calculate maximum principal strain in the cerebrum. The results demonstrated for unhelmeted impacts, falls and ball impacts produce higher maximum principal strain values than stick and shoulder collisions. The strain values for falls and ball impacts were found to be within the range of concussion and traumatic brain injury. The results also showed that men's lacrosse helmets reduced maximum principal strain for follow-through slashing, falls and ball impacts. These findings are novel and demonstrate that for high risk events, maximum principal strain can be reduced by implementing the use of helmets if the rules of the sport do not effectively manage such situations.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.020
      Issue No: Vol. 80 (2018)
  • Positioning of the cross-stitch on the modified Kessler core tendon suture
    • Authors: L. Gil-Santos; M. Monleón-Pradas; F. Gomar-Sancho; J. Más-Estellés
      Pages: 27 - 32
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): L. Gil-Santos, M. Monleón-Pradas, F. Gomar-Sancho, J. Más-Estellés
      Cryopreserved human tendons were sutured with different variations of a modified Kessler-type grasping suture in a series of different designs in order to assess the influence of the distance between the cross-stitch on the core suture (5 and 10 mm from the cut tendon edge) on the peripheral suture. An original mathematical model was employed to explain the mechanical behavior (strength, deformation, and distribution of load) of the different suture designs. The effect of the peripheral epitendinous suture, combined with the distance of the core suture, was evaluated. The variation of core suture distance had no relevant consequences on the overall resilience of the design. However, increasing the distance between the cross-stitches of the core suture reduces the deformation that is absorbed not only by the core suture itself but also by the peripheral suture. Adding a peripheral epitendinous suture to a 10-mm design almost doubles the breaking load in absolute values. The mathematical model predicts that the peripheral suture will support a greater load when the distance of the core suture cross-stitches is increased. The evidence level is II.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.018
      Issue No: Vol. 80 (2018)
  • Formulation and viscoelasticity of mineralised hydrogels for use in
           bone-cartilage interfacial reconstruction
    • Authors: Trina Majumdar; Megan E. Cooke; Bernard M. Lawless; Francis Bellier; Erik A.B. Hughes; Liam M. Grover; Simon W. Jones; Sophie C. Cox
      Pages: 33 - 41
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Trina Majumdar, Megan E. Cooke, Bernard M. Lawless, Francis Bellier, Erik A.B. Hughes, Liam M. Grover, Simon W. Jones, Sophie C. Cox
      Articular cartilage is a viscoelastic tissue whose structural integrity is important in maintaining joint health. To restore the functionality of osteoarthritic joints it is vital that regenerative strategies mimic the dynamic loading response of cartilage and bone. Here, a rotating simplex model was employed to optimise the composition of agarose and gellan hydrogel constructs structured with hydroxyapatite (HA) with the aim of obtaining composites mechanically comparable to human cartilage in terms of their ability to dissipate energy. Addition of ceramic particles was found to reinforce both matrices up to a critical concentration (< 3w/v%). Beyond this, larger agglomerates were formed, as evidenced by micro computed tomography data, which acted as stress risers and reduced the ability of composites to dissipate energy demonstrated by a reduction in tan δ values. A maximum compressive modulus of 450.7±24.9 kPa was achieved with a composition of 5.8w/v% agarose and 0.5w/v% HA. Interestingly, when loaded dynamically (1–20Hz) this optimised formulation did not exhibit the highest complex modulus instead a sample with a higher concentration of mineral was identified (5.8w/v% agarose and 25w/v% HA). Thus, demonstrating the importance of examining the mechanical behaviour of biomaterials under conditions representative of physiological environments. While the complex moduli of the optimised gellan (1.0 ± 0.2MPa at 1Hz) and agarose (1.7 ± 0.2MPa at 1Hz) constructs did not match the complex moduli of healthy human cartilage samples (26.3 ± 6.5MPa at 1Hz), similar tan δ values were observed between 1 and 5Hz. This is promising since these frequencies represent the typical heel strike time of the general population. In summary, this study demonstrates the importance of considering more than just the strength of biomaterials since tissues like cartilage play a more complex role.
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      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.016
      Issue No: Vol. 80 (2018)
  • Effects of water and microbial-based aging on the performance of three
           dental restorative materials
    • Authors: Xinxuan Zhou; Suping Wang; Xian Peng; Yao Hu; Biao Ren; Mingyun Li; Liying Hao; Mingye Feng; Lei Cheng; Xuedong Zhou
      Pages: 42 - 50
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Xinxuan Zhou, Suping Wang, Xian Peng, Yao Hu, Biao Ren, Mingyun Li, Liying Hao, Mingye Feng, Lei Cheng, Xuedong Zhou
      The objective of this study was to evaluate the performance changes of three restorative materials before and after three different aging treatments: storage in distilled water, Streptococcus mutans (S. mutans) and oral salivary microbes suspensions for one month. Resin composite (RC), giomer and glass ionomer cement (GIC) were chosen for aging procedures. Surface morphology, roughness average (Ra), color changes and mechanical properties were all determined before and after aging respectively. Biomass and metabolism difference of early attached biofilm on the material surface were tested through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and lactic acid measurement. The results showed that after S. mutans or salivary microbes aging treatments, GIC group displayed significant morphology changes, with Ra value significantly higher than that before aging (p < .001). Color changes of giomer and GIC group after S. mutans aging were not clinically acceptable. All materials after two microbial-based aging treatments had higher flexural strength than that before aging (p < .05). Giomer after salivary microbes aging had higher elastic modulus than the initial values (p < .05). Additionally, early attached biofilm biomass and lactic acid production in GIC group after S. mutans or salivary microbes aging were higher than that before aging (p < .05). While one-month water aging showed less influences on material performance to some extent. In conclusion, to better simulate the harsh oral environment, in vitro microbial-based aging models showed more advantages in evaluating dental restorative materials’ degradation over time.
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      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.023
      Issue No: Vol. 80 (2018)
  • Effects of cross-linking on mechanical, biological properties and
           biodegradation behavior of Nile tilapia skin collagen sponge as a
           biomedical material
    • Authors: Leilei Sun; Bafang Li; Di Yao; Wenkui Song; Hu Hou
      Pages: 51 - 58
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Leilei Sun, Bafang Li, Di Yao, Wenkui Song, Hu Hou
      The objective of this study was to explore the effects of dehydrothermal treatment (DHT) and glutaraldehyde (GTA) cross-linking on mechanical, biological properties and biodegradation behavior of Nile tilapia skin collagen sponge fabricated by freeze-drying technology. It was found that the GTA cross-linked collagen sponge exhibited a higher degree of cross-linking in comparison with DHT. The extent of increased tensile strength as well as hygroscopicity indicated that GTA cross-linking was superior to DHT in mechanical properties and liquid absorption, which was attributed to different cross-linking mechanisms. Hygroscopicity assay indicated that cross-linking could improve stability of collagen in solutions. No obvious changes in porosity and blood coagulation time were observed whether cross-linking or not. Results from collagenase biodegradation assay in vitro illustrated that GTA-treated collagen sponge was more resistant to collagenase biodegradation, while DHT exhibited negligible resistance. In addition, photochemical stability of collagen sponge was studied by Fourier transforms infrared spectroscopy (FTIR), which indicated that both cross-linking treatments could not change the backbone structure of collagen. Furthermore, the microstructure of collagen sponge was stable after cross-linking. The highly porous and interconnected structure of collagen sponge was helpful to the absorption of wound exudates, supplement of oxygen and cell proliferation, accompanied with good blood compatibility, which indicated that our fabricated collagen sponge could be applied in biomedical materials field as wound dressings.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.006
      Issue No: Vol. 80 (2018)
  • Fracture-free surfaces of CAD/CAM lithium metasilicate glass-ceramic using
           micro-slurry jet erosion
    • Authors: Ling Yin; Takashi Baba; Yoshitaka Nakanishi
      Pages: 59 - 67
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Ling Yin, Takashi Baba, Yoshitaka Nakanishi
      This paper reports the use of micro-slurry jet erosion (MSJE) on CAD/CAM lithium mesilicate glass ceramic (LMGC) that is capable of achieving the fracture-free surface quality. A computer-controlled MSJE process using a low-pressure and low-concentration alumina slurry was applied to diamond-ground LMGC surfaces with surface and subsurface damage. The MSJE processed and diamond-ground LMGC surfaces were examined using scanning electron microscopy (SEM) to examine surface morphology, fractures, and residual defects. 3D confocal laser microscopy (CLM) was used to quantitatively characterize all machined surface textures as a function of processing conditions. Our results show that surface and subsurface damage induced in diamond-ground surfaces were significantly diminished after 50-cycle MSJE processing. Fracture-free surfaces were obtained after 100 MSJE cycles. Our measured parameters of the 3D surface topography included the average surface roughness, maximum peak-valley height, highest peak height, lowest valley height, and kurtosis and absolute skewness of height distributions. All these parameters were significantly reduced with the increase of MSJE cycles. This work implies that MSJE promises to be an effective manufacturing technique for the generation of fracture-free LMGC surfaces which are crucial for high-quality monolithic restorations made from the material.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.022
      Issue No: Vol. 80 (2018)
  • Effect of porous orthopaedic implant material and structure on load
           sharing with simulated bone ingrowth: A finite element analysis comparing
           titanium and PEEK
    • Authors: R. Dana Carpenter; Brett S. Klosterhoff; F. Brennan Torstrick; Kevin T. Foley; J. Kenneth Burkus; Christopher S.D. Lee; Ken Gall; Robert E. Guldberg; David L. Safranski
      Pages: 68 - 76
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): R. Dana Carpenter, Brett S. Klosterhoff, F. Brennan Torstrick, Kevin T. Foley, J. Kenneth Burkus, Christopher S.D. Lee, Ken Gall, Robert E. Guldberg, David L. Safranski
      Osseointegration of load-bearing orthopaedic implants, including interbody fusion devices, is critical to long-term biomechanical functionality. Mechanical loads are a key regulator of bone tissue remodeling and maintenance, and stress-shielding due to metal orthopaedic implants being much stiffer than bone has been implicated in clinical observations of long-term bone loss in tissue adjacent to implants. Porous features that accommodate bone ingrowth have improved implant fixation in the short term, but long-term retrieval studies have sometimes demonstrated limited, superficial ingrowth into the pore layer of metal implants and aseptic loosening remains a problem for a subset of patients. Polyether-ether-ketone (PEEK) is a widely used orthopaedic material with an elastic modulus more similar to bone than metals, and a manufacturing process to form porous PEEK was recently developed to allow bone ingrowth while preserving strength for load-bearing applications. To investigate the biomechanical implications of porous PEEK compared to porous metals, we analyzed finite element (FE) models of the pore structure-bone interface using two clinically available implants with high (> 60%) porosity, one being constructed from PEEK and the other from electron beam 3D-printed titanium (Ti). The objective of this study was to investigate how porous PEEK and porous Ti mechanical properties affect load sharing with bone within the porous architectures over time. Porous PEEK substantially increased the load share transferred to ingrown bone compared to porous Ti under compression (i.e. at 4 weeks: PEEK = 66%; Ti = 13%), tension (PEEK = 71%; Ti = 12%), and shear (PEEK = 68%; Ti = 9%) at all time points of simulated bone ingrowth. Applying PEEK mechanical properties to the Ti implant geometry and vice versa demonstrated that the observed increases in load sharing with PEEK were primarily due to differences in intrinsic elastic modulus and not pore architecture (i.e. 4 weeks, compression: PEEK material/Ti geometry = 53%; Ti material/PEEK geometry = 12%). Additionally, local tissue energy effective strains on bone tissue adjacent to the implant under spinal load magnitudes were over two-fold higher with porous PEEK than porous Ti (i.e. 4 weeks, compression: PEEK = 784 ± 351 microstrain; Ti = 180 ± 300 microstrain; and 12 weeks, compression: PEEK = 298 ± 88 microstrain; Ti = 121 ± 49 microstrain). The higher local strains on bone tissue in the PEEK pore structure were below previously established thresholds for bone damage but in the range necessary for physiological bone maintenance and adaptation. Placing these strain magnitudes in the context of literature on bone adaptation to mechanical loads, this study suggests that porous PEEK structures may provide a more favorable mechanical environment for bone formation and maintenance under spinal load magnitudes than currently available porous 3D-printed Ti, regardless of the level of bone ingrowth.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.017
      Issue No: Vol. 80 (2018)
  • Role of particulate concentration in tooth wear
    • Authors: Oscar Borrero-Lopez; Paul J. Constantino; Brian R. Lawn
      Pages: 77 - 80
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Oscar Borrero-Lopez, Paul J. Constantino, Brian R. Lawn
      Results are presented for wear tests on human molar enamel in silica particle mediums. Data for different particle concentrations show severe wear indicative of material removal by plasticity-induced microcrack formation, in accordance with earlier studies. The wear rates are independent of low vol% particles, consistent with theoretical models in which occlusal loads are distributed evenly over all interfacial microcontacts. However, perhaps counter-intuitively, the wear rate diminishes substantially at higher vol%. This is attributed to a greater proportion of lower-load microcontacts transitioning into a region of mild wear, where microcracking is suppressed. Implications of these results in relation to evolutionary biology and dentistry are explored.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.024
      Issue No: Vol. 80 (2018)
  • Modelling a soft composite accumulator for human mobility assist devices
    • Authors: Robert Shaheen; Marc Doumit
      Pages: 81 - 87
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Robert Shaheen, Marc Doumit
      Research in the field of human mobility assist devices, aiming to reduce the metabolic cost of daily activities, is seeing the benefits of the exclusive use of accumulators to store and release energy during the gait cycle. The Pneumatic Artificial Muscle, used in a passive state, has proven to be a superior choice for these devices when compared to its alternatives, however, challenges regarding muscle pressure dissipation and a limited elongation potential have been identified. A recently developed, novel Soft Composite material has been shown to experimentally replicate the distinctive mechanical behaviour of the Pneumatic Artificial Muscle, without the need for internal pressurization. This paper presents two separate constitutive models to provide a closer insight into the behaviour of these Soft Composite accumulators. Both models were derived from methods involving finite elasticity theory and employed either a structural strain energy function of Holzapfel, Gasser, and Ogden's type or a phenomenological strain energy function of Fung's type. Both models were in good agreement with the experimental data that were collected through a modified extension-inflation test and, therefore, provide a basis for further examination as a Soft Composite design model.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.029
      Issue No: Vol. 80 (2018)
  • Different models for simulation of mechanical behaviour of porous
    • Authors: S. Muñoz; S.M. Castillo; Y. Torres
      Pages: 88 - 96
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): S. Muñoz, S.M. Castillo, Y. Torres
      Commercially pure Titanium (cpTi) and its alloys are the most successful metallic biomaterials for bone replacement, due to its excellent biomechanical and biofunctional balance. However, these materials have higher elastic modulus when compared with bone, leading to the stress-shielding phenomenon and promoting bone resorption. Development of porous implants with low elastic modulus, providing a good mechanical and functional balance (suitable mechanical strength and optimum osseointegration), is the focus of emergent research in advanced Ti-based alloy biomaterials. With the aim of understanding the mechanical behaviour of porous materials with relation to the porosity level and the porous morphology, a new improved model with three different versions have been developed in this work. The proposed FE model combines the simplicity of a 2D periodic geometry with the complex information of the pore morphology extracted from experimentation. The methodology to generate the 2D simulated microstructure is based on a series of nxn pores distributed in a square matrix. The different versions of the model differ in the way of building the porous geometry. In the first version of the model (“Basic-Pattern Model”), the pores are supposed to be circular and periodically distributed in the matrix, following a perfect pattern. The second version of the model (“Pattern Model”) is similar to the previous one, but with elliptic pores with a morphology randomly generated, following statistical information from experiments. In the third version (“Semi-random Model”), a controlled random distribution of the pores is obtained by including a randomness factors in both directions. By making use of the proposed FE model with its different versions, five different porous titanium obtained by the space-holders technique (with porosities θ = 28%, 37%, 47%, 57% and 66%) have been modeled based on experimental information of the pore morphology, and its macroscopic mechanical behaviour has been simulated, showing relatively good agreement with experimental results.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.026
      Issue No: Vol. 80 (2018)
  • Modeling the effects of lipid contamination in
           poly(styrene-isobutylene-styrene) (SIBS)
    • Authors: Mauro Fittipaldi; Landon R. Grace
      Pages: 97 - 103
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Mauro Fittipaldi, Landon R. Grace
      Lipid uptake and subsequent degradation was characterized as a function of molecular weight and styrene content in four different formulations of poly(styrene-block-Isobutylene-block-styrene) (SIBS). Mechanical testing in uniaxial tension at varying lipid concentrations showed a consistent decrease in tensile strength for all specimens due to lipid contamination. Higher styrene content was associated with an improved resistance to lipid intrusion. A decrease in elongation at break was observed for low molecular weight formulations only; an expected result of the stiffer network and local chain motion restriction due to increased entanglements in high molecular weight SIBS. A new, coupled diffusion/finite element method was used to recover the swelling coefficient of the four different SIBS formulations. The Ogden strain-density energy function recovered from unidirectional tensile testing and diffusion properties from gravimetric analysis were used to construct the finite element model. The predicted swelling behavior matched experimental data and the swelling coefficients were recovered for all formulations tested. Results indicate that the higher lipid affinity of the isobutylene phase contributed to increased swelling, as expected. This novel method to calculate swelling coefficient effectively circumvents the inability of commonly-used thermal deswelling methods to characterize lipid and oil-induced swelling behavior; enabling better prediction of long-term in vivo performance of polymer-based biomedical devices and more accurate evaluation of lipid-induced degradation and swelling.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.030
      Issue No: Vol. 80 (2018)
  • Larger vertebral endplate concavities cause higher failure load and work
           at failure under high-rate impact loading of rabbit spinal explants
    • Authors: S. Dudli; W. Enns-Bray; Y. Pauchard; A. Römmeler; A.J. Fields; S.J. Ferguson; B. Helgason
      Pages: 104 - 110
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): S. Dudli, W. Enns-Bray, Y. Pauchard, A. Römmeler, A.J. Fields, S.J. Ferguson, B. Helgason
      Vertebral fractures are among the most common of all osteoporosis related fracture types and its risk assessment is largely based on bone quality measures. Morphometric parameters are not yet considered, although endplate thickness and concavity shape were found to be important in fracture prediction in low-rate tests. We hypothesized that, under high-rate impact loading, the shape and size of the central endplate concavity are of key importance for fracture prediction. Therefore, we tested rabbit spinal segment explants in vitro under high-rate impact loading. With a combination of microCT to describe endplate morphometry, high-speed video imaging, and impact force measurement, endplate morphometry was correlated to the mechanical response. We found that endplate concavity shape and volume were important in describing the mechanical response: larger concavities caused higher failure load. We suggest a model for the fracture mechanism under high-rate impact loading, considering the morphometry of the endplates: wider and more voluminous concavities are protective whereas steeper slopes of the concavity edges and increasing bone volume fraction of the central endplate moiety are disadvantageous. Therefore, the shape and size of endplate morphometry are important in vertebral fracture prediction and should be considered included in vertebral fracture risk assessment.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.019
      Issue No: Vol. 80 (2018)
  • Influence of crosslinking on the mechanical behavior of 3D printed
           alginate scaffolds: Experimental and numerical approaches
    • Authors: Saman Naghieh; Mohammad Reza Karamooz-Ravari; MD Sarker; Eva Karki; Xiongbiao Chen
      Pages: 111 - 118
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Saman Naghieh, Mohammad Reza Karamooz-Ravari, MD Sarker, Eva Karki, Xiongbiao Chen
      Tissue scaffolds fabricated by three-dimensional (3D) bioprinting are attracting considerable attention for tissue engineering applications. Because the mechanical properties of hydrogel scaffolds should match the damaged tissue, changing various parameters during 3D bioprinting has been studied to manipulate the mechanical behavior of the resulting scaffolds. Crosslinking scaffolds using a cation solution (such as CaCl2) is also important for regulating the mechanical properties, but has not been well documented in the literature. Here, the effect of varied crosslinking agent volume and crosslinking time on the mechanical behavior of 3D bioplotted alginate scaffolds was evaluated using both experimental and numerical methods. Compression tests were used to measure the elastic modulus of each scaffold, then a finite element model was developed and a power model used to predict scaffold mechanical behavior. Results showed that crosslinking time and volume of crosslinker both play a decisive role in modulating the mechanical properties of 3D bioplotted scaffolds. Because mechanical properties of scaffolds can affect cell response, the findings of this study can be implemented to modulate the elastic modulus of scaffolds according to the intended application.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.034
      Issue No: Vol. 80 (2018)
  • Continuous functionally graded porous titanium scaffolds manufactured by
           selective laser melting for bone implants
    • Authors: Changjun Han; Yan Li; Qian Wang; Shifeng Wen; Qingsong Wei; Chunze Yan; Liang Hao; Jie Liu; Yusheng Shi
      Pages: 119 - 127
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Changjun Han, Yan Li, Qian Wang, Shifeng Wen, Qingsong Wei, Chunze Yan, Liang Hao, Jie Liu, Yusheng Shi
      A significant requirement for a bone implant is to replicate the functional gradient across the bone to mimic the localization change in stiffness. In this work, continuous functionally graded porous scaffolds (FGPSs) based on the Schwartz diamond unit cell with a wide range of graded volume fraction were manufactured by selective laser melting (SLM). The micro-topology, strut dimension characterization and effect of graded volume fraction on the mechanical properties of SLM-processed FGPSs were systematically investigated. The micro-topology observations indicate that diamond FGPSs with a wide range of graded volume fraction from 7.97% to 19.99% were fabricated without any defects, showing a good geometric reproduction of the original designs. The dimensional characterization demonstrates the capability of SLM in manufacturing titanium diamond FGPSs with the strut size of 483–905µm. The elastic modulus and yield strength of the titanium diamond FGPSs can be tailored in the range of 0.28–0.59GPa and 3.79–17.75MPa respectively by adjusting the graded volume fraction, which are comparable to those of the cancellous bone. The mathematical relationship between the graded porosity and compression properties of a FGPS was revealed. Furthermore, two equations based on the Gibson and Ashby model have been established to predict the modulus and yield strength of SLM-processed diamond FGPSs. Compared to homogeneous diamond porous scaffolds, FGPSs provide a wide range of mutative pore size and porosity, which are potential to be tailored to optimize the pore space for bone tissue growth. The findings provide a basis of new methodologies to design and manufacture superior graded scaffolds for bone implant applications.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.013
      Issue No: Vol. 80 (2018)
  • A novel fracture mechanics model explaining the axial penetration of
    • Authors: Sloan A. Kulper; K.Y. Sze; Christian X. Fang; Xiaodan Ren; Margaret Guo; Kerstin Schneider; Frankie Leung; William Lu; Alfonso Ngan
      Pages: 128 - 136
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Sloan A. Kulper, K.Y. Sze, Christian X. Fang, Xiaodan Ren, Margaret Guo, Kerstin Schneider, Frankie Leung, William Lu, Alfonso Ngan
      Many features of orthopaedic implants have been previously examined regarding their influence on migration in trabecular bone under axial loading, with screw thread design being one of the most prominent examples. There has been comparatively little investigation, however, of the influence that implant tip design has on migration under axial loads. We present a novel fracture mechanics model that explains how differences in tip design affect the force required for axial penetration of porous, compressible solids similar to trabecular bone. Three tip designs were considered based on typical 5 mm diameter orthopaedic locking screws: flat and conical tip designs, as well as a novel elastomeric tip. Ten axial penetration trials were conducted for each tip design. In order to isolate the effect of tip design on axial migration from that of the threads, smooth steel rods were used. Tip designs were inserted into polyurethane foam commonly used to represent osteoporotic trabecular bone tissue (ASTM Type 10, 0.16 g/cc) to a depth of 10 mm at a rate of 2 mm/min, while force and position were recorded. At maximum depth, elastomeric tips were found to require the greatest force for axial migration (mean of 248.24 N, 95% Confidence Interval [CI]: 238.1–258.4 N), followed by conical tips (mean of 143.46 N, 95% CI: 142.1–144.9 N), and flat tips (mean of 113.88 N, 95% CI: 112.2–115.5 N). This experiment was repeated in cross-section while recording video of material compaction through a transparent window. Strain fields for each tip design were then generated from these videos using digital image correlation (DIC) software. A novel fracture mechanics model, combining the Griffith with porous material compaction, was developed to explain the performance differences observed between the three tip designs. This model predicted that steady-state stress would be roughly the same (~ 4 MPa) across all designs, a finding consistent with the experimental results. The model also suggested that crack formation and friction are negligible mechanisms of energy absorption during axial penetration of porous compressible solids similar to trabecular bone. Material compaction appears to be the dominant mechanism of energy absorption, regardless of tip design. The cross-sectional area of the compacted material formed during migration of the implant tip during axial penetration was shown to be a strong determinant of the force required for migration to occur (Pearson Coefficient = 0.902, p < .001). As such, implant tips designed to maximize the cross-sectional area of compacted material – such as the elastomeric and conical tips in the present study – may be useful in reducing excessive implant migration under axial loads in trabecular bone.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.025
      Issue No: Vol. 80 (2018)
  • Physico-chemical characterization and biocompatibility of hydroxyapatite
           derived from fish waste
    • Authors: Hirochi Yamamura; Victor Hugo Pereira da Silva; Pedro Luiz Menin Ruiz; Valter Ussui; Dolores Ribeiro Ricci Lazar; Ana Claudia Muniz Renno; Daniel Araki Ribeiro
      Pages: 137 - 142
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Hirochi Yamamura, Victor Hugo Pereira da Silva, Pedro Luiz Menin Ruiz, Valter Ussui, Dolores Ribeiro Ricci Lazar, Ana Claudia Muniz Renno, Daniel Araki Ribeiro
      The aim of this study was to synthesize hydroxyapatite (HAP) powder from fish waste. The powder was characterized through X-ray diffraction, Fourier transform infrared spectroscopy, ion exchange chromatography, scanning electron microscopy and plasma emission spectrometry. The cyto- and genotoxicity was carried out to demonstrate biocompatibility in vivo by means of rat subcutaneous tissue test. The results showed that the visible crystalline nature of typical apatite crystal structure when they were calcined at 800 °C. Infrared spectroscopy analysis showed similar composition to HAP standard with the presence of carbonate ion demonstrated by wave number values of 871 cm−1 and 1420 cm−1 for calcinations at 800 °C. The scanning electronmicrographies depicted the crystal morphology and porous nature with average pore size of ~10 µm. Plasma emission spectrometry and ion exchange chromatography confirmed the presence of Ca and P in the samples. The mean of calcium content was 36.8; Mg was 0.8, Na was 0.7 and K was 0.5. Rat subcutaneous tissue test revealed that HAP presented biocompatibility. Furthermore, the lack of cyto- and genotoxicity in blood, liver, kidney and lung were noticed after 30 days of HAP implantation. Taken together, our results demonstrated that HAP from fish waste exhibits a great potential for using as biomaterial since is represents a simple, effective, low-cost process and satisfactory degree of biocompatibility.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.035
      Issue No: Vol. 80 (2018)
  • Improved tribocorrosion performance of bio-functionalized TiO2 nanotubes
           under two-cycle sliding actions in artificial saliva
    • Authors: Sofia A. Alves; André L. Rossi; Ana R. Ribeiro; Fatih Toptan; Ana M. Pinto; Tolou Shokuhfar; Jean-Pierre Celis; Luís A. Rocha
      Pages: 143 - 154
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Sofia A. Alves, André L. Rossi, Ana R. Ribeiro, Fatih Toptan, Ana M. Pinto, Tolou Shokuhfar, Jean-Pierre Celis, Luís A. Rocha
      After insertion into bone, dental implants may be subjected to tribocorrosive conditions resulting in the release of metallic ions and solid wear debris, which can induce to peri-implant inflammatory reactions accompanied by bone loss, and ultimately implant loosening. Despite the promising ability of TiO2 nanotubes (NTs) to improve osseointegration and avoid infection-related failures, the understanding of their degradation under the simultaneous action of wear and corrosion (tribocorrosion) is still very limited. This study aims, for the first time, to study the tribocorrosion behavior of bio-functionalized TiO2 NTs submitted to two-cycle sliding actions, and compare it with conventional TiO2 NTs. TiO2 NTs grown by anodization were doped with bioactive elements, namely calcium (Ca), phosphorous (P), and zinc (Zn), through reverse polarization anodization treatments. Characterization techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and scanning transmission electron microscopy (STEM), were used to characterize the films. Tribocorrosion tests were carried out in artificial saliva (AS) by applying two cycles of reciprocating sliding actions. The open circuit potential (OCP) was monitored before, during, and after both cycles of sliding, during which the coefficient of friction (COF) was calculated. The resulting wear scars were analyzed by SEM and EDS, and wear volume measurements were performed by 2D profilometry. Finally, the mechanical features of TiO2 NTs were accessed by nanoindentation. The results show that bio-functionalized TiO2 NTs display an enhanced tribocorrosion performance, ascribed to the growth of a nano-thick oxide film at Ti/TiO2 NTs interface, which significantly increased their adhesion strength to the substrate and consequently their hardness. Furthermore, it was discovered that during tribo-electrochemical solicitations, the formation of a P-rich tribofilm takes place, which grants both electrochemical protection and resistance to mechanical wear. This study provides fundamental and new insights for the development of multifunctional TiO2 NTs with long-term biomechanical stability and improved clinical outcomes.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.038
      Issue No: Vol. 80 (2018)
  • Viscoelastic properties of multi-layered cellularized vascular tissues
           fabricated from collagen gel
    • Authors: Dawit G. Seifu; Sébastien Meghezi; Larry Unsworth; Kibret Mequanint; Diego Mantovani
      Pages: 155 - 163
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Dawit G. Seifu, Sébastien Meghezi, Larry Unsworth, Kibret Mequanint, Diego Mantovani
      Since collagen is one of the major extracellular matrix components in vascular tissues, its use for vascular tissue engineering has several advantages. However, collagen extraction and processing for tissue engineering application alters its structure. As a result, collagen-based vascular constructs show poor mechanical properties compared to native tissues. In this work, multi-layer (single, double, and triple) vascular tissue constructs were engineered from porcine smooth muscle cells (PSMCs) entrapped in collagen gel by concentrically and sequentially layering after compaction of the previous layer(s). The engineered tissues were matured for either 14 or 21 days to allow the collagen gel to remodel before viscoelasticity, compliance, histological, and protein expression studies were conducted. While there was no significant difference upon addition of the different layers on the elastic modulus (p > .05), the viscous modulus of the single layer construct was significantly lower than the double and triple layer constructs (p < .05). Increasing the number of layers of the cellularized collagen construct increased the wall thickness and the viscous modulus of the construct. Furthermore, the cellularized single-layer construct had a relatively high compliance, but the double and triple layer constructs had compliance values comparable to both engineered vessels and native vessels. PSMCs were uniformly distributed throughout the cross-section and expressed the anticipated marker proteins smooth muscle-α actin, calponin, and smooth muscle myosin heavy chain. Taken together, this study demonstrated the viscoelastic responsiveness of multi-layer collagen-gel based vascular tissues.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.021
      Issue No: Vol. 80 (2018)
  • A simple model for constant storage modulus of poly (lactic acid)/poly
           (ethylene oxide)/carbon nanotubes nanocomposites at low frequencies
           assuming the properties of interphase regions and networks
    • Authors: Yasser Zare; Sungsoo Rhim; Hamid Garmabi; Kyong Yop Rhee
      Pages: 164 - 170
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Yasser Zare, Sungsoo Rhim, Hamid Garmabi, Kyong Yop Rhee
      The networks of nanoparticles in nanocomposites cause solid-like behavior demonstrating a constant storage modulus at low frequencies. This study examines the storage modulus of poly (lactic acid)/poly (ethylene oxide)/carbon nanotubes (CNT) nanocomposites. The experimental data of the storage modulus in the plateau regions are obtained by a frequency sweep test. In addition, a simple model is developed to predict the constant storage modulus assuming the properties of the interphase regions and the CNT networks. The model calculations are compared with the experimental results, and the parametric analyses are applied to validate the predictability of the developed model. The calculations properly agree with the experimental data at all polymer and CNT concentrations. Moreover, all parameters acceptably modulate the constant storage modulus. The percentage of the networked CNT, the modulus of networks, and the thickness and modulus of the interphase regions directly govern the storage modulus of nanocomposites. The outputs reveal the important roles of the interphase properties in the storage modulus.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.037
      Issue No: Vol. 80 (2018)
  • Influence of suture size on the frictional performance of surgical suture
           evaluated by a penetration friction measurement approach
    • Authors: Gangqiang Zhang; Xiangqiong Zeng; Yibo Su; F.X. Borras; Matthijn B. de Rooij; Tianhui Ren; Emile van der Heide
      Pages: 171 - 179
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Gangqiang Zhang, Xiangqiong Zeng, Yibo Su, F.X. Borras, Matthijn B. de Rooij, Tianhui Ren, Emile van der Heide
      The frictional performances of surgical sutures have been found to play a vital role in their functionality. The purpose of this paper is to understand the frictional performance of multifilament surgical sutures interacting with skin substitute, by means of a penetration friction apparatus (PFA). The influence of the size of the surgical suture was investigated. The relationship between the friction force and normal force was considered, in order to evaluate the friction performance of a surgical suture penetrating a skin substitute. The friction force was measured by PFA. The normal force applied to the surgical suture was estimated based on a Hertzian contact model, a finite element model (FEM), and a uniaxial deformation model (UDM). The results indicated that the penetration friction force increased as the size of the multifilament surgical suture increased. In addition, when the normal force was predicted by UDM, it was found that the ratio between the friction force and normal force decreased as the normal force increased. A comparison of the results suggested that the UDM was appropriate in predicting the frictional behavior of surgical suturing.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.003
      Issue No: Vol. 80 (2018)
  • Assessment of nanoscopic dynamic mechanical properties and B-C-N triad
           effect on MWCNT/h-BNNP nanofillers reinforced HDPE hybrid composite using
           oscillatory nanoindentation: An insight into medical applications
    • Authors: Nitesh Dhar Badgayan; Santosh Kumar Sahu; Sutanu Samanta; P.S. Rama Sreekanth
      Pages: 180 - 188
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Nitesh Dhar Badgayan, Santosh Kumar Sahu, Sutanu Samanta, P.S. Rama Sreekanth
      A thrust on improvement of different properties of polymer has taken a contemporary route with advent of nanofillers. Although several nanofillers are existent; MultiWalled Carbon Nanotubes- (MWCNTs) and h-Boron Nitride nanoplatelets-(h-BNNPs) unique combination of 1D and 2D dimensional geometry aids an advantage of B-C-N triad elemental effects on properties of tested samples. The current study aims to investigate the effects of MWCNT and h-BNNP reinforcement in High Density Polyethylene (HDPE) for high load bearing areas of medical applications requiring both elastic and viscous behavior. The results were analyzed keeping a view of its application in areas like HDPE based fracture fixation plates, acetabular cups and others. The composite and hybrid samples with different loadings were prepared after surface modification of nanofillers by mechanical mixing and molding technique. The dynamic nano-mechanical properties like storage modulus, loss modulus and tan delta were assessed for each sample during frequency swept from 10 to 220 Hz. The viscoelastic properties like hc/hm, H/E, elastic-plastic deformation were investigated and evaluated. At a frequency of 10 Hz, the storage and loss modulus of 0.1 CNT increased by 37.56% and decreased by 23.52% respectively on comparison with pure HDPE. This infers a good elastic as well as viscous behavior. Overall elastic behavior of 0.1 CNT was confirmed from tan delta evaluation. The interaction between B-C-N elemental triad had significant effect on creep strength, visco-damping property (hc/hm and H/E), elastic plastic displacement and pile-up and sink-in behavior. Highest creep strength and visco-damping property was exhibited by 0.25 CNT/0.15 BNNP hybrid. The elastic-plastic displacement of hybrid composite was noted as least, which decreased by 30% on comparison with pure HDPE. It can be inferred that presence of 1D-MWCNT and 2D-h-BNNP had significant effect on important dynamic viscoelastic and creep properties of HDPE based hybrid composites.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.027
      Issue No: Vol. 80 (2018)
  • Influence of glycosaminoglycans on the properties of thin films based on
           chitosan/collagen blends
    • Authors: B. Kaczmarek; A. Sionkowska; J. Skopinska-Wisniewska
      Pages: 189 - 193
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): B. Kaczmarek, A. Sionkowska, J. Skopinska-Wisniewska
      Thin films based on chitosan, collagen, and glycosaminoglycans isolated from fish skin were obtained by solvent evaporation. The films were characterized by different analyses, e.g. surface free energy determination, swelling tests, roughness, mechanical and thermal measurements. Moreover, the degradation studies were carried out by the film treatment with collagenase. The results showed that the properties of the films based on chitosan and collagen can be modified by the glycosaminoglycans addition. It was noticed that the addition of glycosaminoglycans enhances the surface hydrophilicity and reduces surface free energy. Surfaces of films modified by glycosaminoglycans (GAGs) show more roughness which inhibits the risk of biofilm formation. The highest films swelling was obtained after 2 h immersion in phosphate-buffered saline (PBS). After their immersion in PBS, the films were more elastic, which was assumed on the basis of the elongation at break values higher than in the case of films on a dry surface. The proposed films can create biocompatible coatings for biomedical applications.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.006
      Issue No: Vol. 80 (2018)
  • Micromechanics of brain white matter tissue: A fiber-reinforced
           hyperelastic model using embedded element technique
    • Authors: Seyed Abdolmajid Yousefsani; Amir Shamloo; Farzam Farahmand
      Pages: 194 - 202
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Seyed Abdolmajid Yousefsani, Amir Shamloo, Farzam Farahmand
      A transverse-plane hyperelastic micromechanical model of brain white matter tissue was developed using the embedded element technique (EET). The model consisted of a histology-informed probabilistic distribution of axonal fibers embedded within an extracellular matrix, both described using the generalized Ogden hyperelastic material model. A correcting method, based on the strain energy density function, was formulated to resolve the stiffness redundancy problem of the EET in large deformation regime. The model was then used to predict the homogenized tissue behavior and the associated localized responses of the axonal fibers under quasi-static, transverse, large deformations. Results indicated that with a sufficiently large representative volume element (RVE) and fine mesh, the statistically randomized microstructure implemented in the RVE exhibits directional independency in transverse plane, and the model predictions for the overall and local tissue responses, characterized by the normalized strain energy density and Cauchy and von Mises stresses, are independent from the modeling parameters. Comparison of the responses of the probabilistic model with that of a simple uniform RVE revealed that only the first one is capable of representing the localized behavior of the tissue constituents. The validity test of the model predictions for the corona radiata against experimental data from the literature indicated a very close agreement. In comparison with the conventional direct meshing method, the model provided almost the same results after correcting the stiffness redundancy, however, with much less computational cost and facilitated geometrical modeling, meshing, and boundary conditions imposing. It was concluded that the EET can be used effectively for detailed probabilistic micromechanical modeling of the white matter in order to provide more accurate predictions for the axonal responses, which are of great importance when simulating the brain trauma or tumor growth.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.002
      Issue No: Vol. 80 (2018)
  • Strains in trussed spine interbody fusion implants are modulated by load
           and design
    • Authors: Jason P. Caffrey; Eloy Alonso; Koichi Masuda; Jessee P. Hunt; Cameron N. Carmody; Timothy M. Ganey; Robert L. Sah
      Pages: 203 - 208
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Jason P. Caffrey, Eloy Alonso, Koichi Masuda, Jessee P. Hunt, Cameron N. Carmody, Timothy M. Ganey, Robert L. Sah
      Titanium cages with 3-D printed trussed open-space architectures may provide an opportunity to deliver targeted mechanical behavior in spine interbody fusion devices. The ability to control mechanical strain, at levels known to stimulate an osteogenic response, to the fusion site could lead to development of optimized therapeutic implants that improve clinical outcomes. In this study, cages of varying design (1.00 mm or 0.75 mm diameter struts) were mechanically characterized and compared for multiple compressive load magnitudes in order to determine what impact certain design variables had on localized strain. Each cage was instrumented with small fiducial sphere markers (88 total) at each strut vertex of the truss structure, which comprised of 260 individual struts. Cages were subjected to a 50 N control, 1000 N, or 2000 N compressive load between contoured loading platens in a simulated vertebral fusion condition, during which the cages were imaged using high-resolution micro-CT. The cage was analyzed as a mechanical truss structure, with each strut defined as the connection of two vertex fiducials. The deformation and strain of each strut was determined from 50 N control to 1000 N or 2000 N load by tracking the change in distance between each fiducial marker. As in a truss system, the number of struts in tension (positive strain) and compression (negative strain) were roughly equal, with increased loads resulting in a widened distribution (SD) compared with that at 50 N tare load indicating increased strain magnitudes. Strain distribution increased from 1000 N (+156 ± 415 με) to 2000 N (+180 ± 605 με) in 1.00 mm cages, which was similar to 0.75 mm cages (+132 ± 622 με) at 1000 N load. Strain amplitudes increased 42%, from 346με at 1000 N to 492με at 2000 N, for 1.00 mm cages. At 1000 N, strain amplitude in 0.75 mm cages (481με) was higher by 39% than that in 1.00 mm cages. These amplitudes corresponded to the mechanobiological range of bone homeostasis+formation, with 63 ± 2% (p < .05 vs other groups), 72 ± 3%, and 73 ± 1% of struts within that range for 1.00 mm at 1000 N, 1.00 mm at 2000 N, and 0.75 mm at 1000 N, respectively. The effective compressive modulus for both cage designs was also dependent on strut diameter, with modulus decreasing from 12.1 ± 2.3 GPa (1.25 mm) to 9.2 ± 7.5 GPa (1.00 mm) and 3.8 ± 0.6 GPa (0.75 mm). This study extended past micro-scale mechanical characterization of trussed cages to compare the effects of design on cage mechanical behavior at moderate (1000 N) and strenuous (2000 N) load levels. The findings suggest that future cage designs may be modulated to target desired mechanical strain regimes at physiological loads.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.004
      Issue No: Vol. 80 (2018)
  • Biodegradation and mechanical behavior of an advanced
           bioceramic-containing Mg matrix composite synthesized through in-situ
           solid-state oxidation
    • Authors: S. NaddafDezfuli; J.C. Brouwer; J.M.C. Mol; F.C.T. van der Helm; J. Zhou
      Pages: 209 - 221
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): S. NaddafDezfuli, J.C. Brouwer, J.M.C. Mol, F.C.T. van der Helm, J. Zhou
      Recent studies have shown great potential of Mg matrix composites for biodegradable orthopedic devices. However, the poor structural integrity of these composites, which results in excessive localized corrosion and premature mechanical failure, has hindered their widespread applications. In this research, an in-situ Powder Metallurgy (PM) method was used to fabricate a novel biodegradable Mg-bredigite composite and to achieve enhanced chemical interfacial locking between the constituents by triggering a solid-state thermochemical reaction between Mg and bredigite particles. The reaction resulted in a highly densified and integrated microstructure, which prevented corrosion pits from propagating when the composite was immersed in a physiological solution. In addition, chemical interlocking between the constituents prohibited interparticle fracture and subsequent surface delamination during compression testing, enabling the composite to withstand larger plastic deformation before mechanical failure. Furthermore, the composite was proven to be biocompatible and capable of maintaining its ultimate compressive strength in the strength range of cortical bone after 25-day immersion in DMEM. The research provided the necessary information to guide further research towards the development of a next generation of biodegradable Mg matrix composites with enhanced chemical interlocking.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.014
      Issue No: Vol. 80 (2018)
  • Material properties of the brain in injury-relevant conditions –
           Experiments and computational modeling
    • Authors: Wei Zhao; Bryan Choate; Songbai Ji
      Pages: 222 - 234
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Wei Zhao, Bryan Choate, Songbai Ji
      Material properties of the brain have been extensively studied but remain poorly characterized. The vast variations in constitutive models and material constants are well documented. However, no study exists to translate the variations into disparities in impact-induced brain strains most relevant to brain injury. Here, we reviewed a subset of injury-relevant brain material properties either characterized in experiments or adopted in recent head injury models. To highlight how variations in measured brain material properties manifested in simulated brain strains, we selected six experiments that have provided a complete set of brain material model and constants to implement a common head injury model. Responses resulting from two extreme events representing a high-rate cadaveric head impact and a low-rate in vivo head rotation, respectively, varied substantially. We hypothesized, and further confirmed, that the time-varying shear moduli at the appropriate time scales (e.g., ~5 ms and ~40 ms corresponding to the impulse durations of the major acceleration peaks for the two impacts, respectively), rather than the initial or long-term shear moduli, were the most indicative of impact-induced brain strains. These results underscored the need to implement measured brain material properties into an actual head injury model for evaluation. They may also provide guidelines to better characterize brain material properties in future experiments and head injury models. Finally, our finding provided a practical solution to satisfy head injury model validation requirements at both ends of the impact severity spectrum. This would improve the confidence in model simulation performance across a range of time scales relevant to concussion and sub-concussion in the real-world.
      Graphical abstract image

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.005
      Issue No: Vol. 80 (2018)
  • Assessment of titanium metallization thin film deposited on alumina
           substrate: Microstructure and nano-indentation
    • Authors: Xuegang Xing; Hefeng Wang; Gesheng Xiao; Shangyu Yang; Xuefeng Shu
      Pages: 235 - 245
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Xuegang Xing, Hefeng Wang, Gesheng Xiao, Shangyu Yang, Xuefeng Shu
      Surface titanium (Ti) metallization was conducted on alumina (Al2O3) through chemical vapor deposition (CVD) method derived from non-contact pack cementation. The effects of different deposition temperature (1000 °C, 1050 °C, and 1100 °C) were examined in this scenario. The morphology, phase composition, and interfacial defects of the resulting films were systematically investigated through scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. The nanomechanical characterization of the proposed thin films was evaluated by conducting nano-indentation tests at different depths. The results revealed that uniform Ti films were coated on the Al2O3 substrate. During coating, the atoms on the matrix surface were driven to form different structure due to different deposition temperature, leading to disparate morphologies of the surface and the interface, which consequently influenced the binding force between the film and the substrate. Moreover, the nanomechanical properties were found to be related to the internal and interface structure. Decreased modulus and hardness were obtained for metallization films treated at 1050 °C, and plastic deformation was the main deformation pattern.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.036
      Issue No: Vol. 80 (2018)
  • Effects of microstructure transformation on mechanical properties,
           corrosion behaviors of Mg-Zn-Mn-Ca alloys in simulated body fluid
    • Authors: Yuan Zhang; Jianxing Li; Jingyuan Li
      Pages: 246 - 257
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Yuan Zhang, Jianxing Li, Jingyuan Li
      Magnesium and its alloys have unique advantages to act as resorbable bone fixation materials, due to their moderate mechanical properties and biocompatibility, which are similar to those of human tissue. However, early resorption and insufficient mechanical strength are the main problems that hinder their application. Herein, the effects of microstructure transformation on the mechanical properties and corrosion performance of Mg-Zn-Mn-Ca were investigated with electrochemical and immersion measurements at 37 °C in a simulated body fluid (SBF). The results showed that the number density of Ca2Mg6Zn3/Mg2Ca precipitates was remarkably reduced and grain sizes were gradually increased as the temperature increased. The alloy that received the 420 °C/24 h treatment demonstrated the best mechanical properties and lowest corrosion rate (5.94 mm/a) as well as presented a compact and denser film than the others. The improvement in mechanical properties could be explained by the eutectic compounds and phases (Mg2Ca/Ca2Mg6Zn3) gradually dissolving into a matrix, which caused severely lattice distortion and facilitated structural re-arrangement of the increased Ca solute. Moreover, the difference in potential between the precipitates and the matrix is the main essence for micro-galvanic corrosion formation as well as accelerated the dissolution activity and current exchange density at the Mg/electrolyte interface. As a result, the best Mg alloys corrosion resistance must be matched with a moderate grain size and phase volume fractions.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.01.028
      Issue No: Vol. 80 (2018)
  • Bonding of composite cements to zirconia: A systematic review and
           meta-analysis of in vitro studies
    • Authors: Putsadeeporn Thammajaruk; Masanao Inokoshi; Shanley Chong; Massimiliano Guazzato
      Pages: 258 - 268
      Abstract: Publication date: April 2018
      Source:Journal of the Mechanical Behavior of Biomedical Materials, Volume 80
      Author(s): Putsadeeporn Thammajaruk, Masanao Inokoshi, Shanley Chong, Massimiliano Guazzato
      Objectives The aim of this study was to systematically review the literature and statistically analyze bond strength data to identify the influence that composite cements, type of test methodology, chemical and mechanical pre-treatments have on the bond strength of composite cements to zirconia in three different artificial aging conditions. Methods The literature was electronically searched in MEDLINE, PUBMED, EMBASE, and SCOPUS to select relevant articles that evaluated the bond strength between zirconia and composite cements. A manual search was performed by scanning the reference lists of included studies. All articles were published online before December 2016 and in English. From electronic database and manual searches, 444 studies were identified; 161 articles with 1632 test results met the inclusion criteria. Test results were assigned into 3 aging conditions: non-aged, intermediate-aged and aged groups. Generalized estimating equations (GEE) were used to explore actual mean bond strengths. As the bond strength is a non-negative value, lognormal distribution was used. Results In non-aged condition, data showed statistically significant interactions between cement type and type of test. There was no statistically significant interaction between mechanical and chemical pre-treatments. In intermediate-aged and aged conditions, data showed no statistically significant interactions between mechanical and chemical pre-treatments and between cement type and type of test. Conclusions This meta-analysis appeared to indicate that mechanical pre-treatments, and in particular ceramic coating, combined with methacryloyloxydecyl dihydrogen phosphate (MDP) containing primers yielded the highest long-term bond strength (aged-condition). However, data are limited and caution should be exercised before applying these results to clinical situations.

      PubDate: 2018-03-08T16:55:11Z
      DOI: 10.1016/j.jmbbm.2018.02.008
      Issue No: Vol. 80 (2018)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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Fax: +00 44 (0)131 4513327
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