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A Russo, M Bianchi, M Sartori, M Boi, G Giavaresi, D M Salter, M Jelic, M C Maltarello, A Ortolani, S Sprio, M Fini, A Tampieri, M Marcacci
Magnetic scaffolds have recently attracted significant attention in tissue engineering due to the prospect of improving bone tissue formation by conveying soluble factors such as growth factors, hormones, and polypeptides directly to the site of implantation, as well as to the possibility of improving implant fixation and stability. The objective of this study was to compare bone tissue formation in a preclinical rabbit model of critical femoral defect treated either with a hydroxyapatite (HA)/magnetite (90/10 wt %) or pure HA porous scaffolds at 4 and 12 weeks after implantation...
February 15, 2017: Journal of Biomedical Materials Research. Part B, Applied Biomaterials
Huixiang Huang, Wencheng Tang, Qiyan Tan, Bin Yan
The present study developed and implemented a new visco-hyperelastic model that is capable of predicting the time-dependent biomechanical behavior of the periodontal ligament. The constitutive model has been implemented into the finite element package ABAQUS by means of a user-defined material subroutine (UMAT). The stress response is decomposed into two constitutive parts in parallel which are a hyperelastic and a time-dependent viscoelastic stress response. In order to identify the model parameters, the indentation equation based on V-W hyperelastic model and the indentation creep model are developed...
January 31, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Shao-Ping Wang, Jian Xu
Combining the high-entropy alloy (HEA) concept with property requirement for orthopedic implants, we designed a Ti20Zr20Nb20Ta20Mo20 equiatomic HEA. The arc-melted microstructures, compressive properties and potentiodynamic polarization behavior in phosphate buffer solution (PBS) were studied in detail. It was revealed that the as-cast TiZrNbTaMo HEA consisted of dual phases with bcc structure, major bcc1 and minor bcc2 phases with the lattice parameters of 0.3310nm and 0.3379nm, respectively. As confirmed by nanoindentation tests, the bcc1 phase is somewhat harder and stiffer than the bcc2 phase...
April 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
A S Fawzy, B M Priyadarshini, S T Selvan, T B Lu, J Neo
Previous studies reported that grapeseed extract (GSE), which is rich in proanthocyanidins (PAs), improves the biodegradation resistance of demineralized dentin. This study aimed to investigate the effect of a new GSE delivery strategy to demineralized dentin through loading into biodegradable polymer poly-[lactic-co-glycolic acid] (PLGA) nanoparticles on the biodegradation resistance in terms of structural stability and surface/bulk mechanical and biochemical properties with storage time in collagenase-containing solutions...
February 1, 2017: Journal of Dental Research
Ya Shpotyuk, S Adamiak, A Dziedzic, J Szlezak, W Bochnowski, J Cebulski
Nanoscale inhomogeneities mapping in Ga-modified As2Se3 glass was utilized exploring possibilities of nanoindentation technique using a Berkovitch-type diamond tip. Structural inhomogeneities were detected in Gax(As0.40Se0.60)100-x alloys with more than 3 at.% of Ga. The appeared Ga2Se3 nanocrystallites were visualized in Ga-modified arsenic selenide glasses using scanning and transmission electron microscopy. The Ga additions are shown to increase nanohardness and Young's modulus, this effect attaining an obvious bifurcation trend in crystallization-decomposed Ga5(As0...
December 2017: Nanoscale Research Letters
Min Han, Quan-Li Li, Ying Cao, Hui Fang, Rong Xia, Zhi-Hong Zhang
A novel agarose hydrogel biomimetic mineralization system loaded with calcium and phosphate was used to remineralize dentin and induce the oriented densely parallel packed HA layer on defective dentin surface in vivo in a rabbit model. Firstly, the enamel of the labial surface of rabbits' incisor was removed and the dentin was exposed to oral environment. Secondly, the hydrogel biomimetic mineralization system was applied to the exposed dentin surface by using a custom tray. Finally, the teeth were extracted and evaluated by scanning electron microscopy, X-ray diffraction, and nanoindentation test after a certain time of mineralization intervals...
February 7, 2017: Scientific Reports
Eric Aguado, Guillaume Mabilleau, Eric Goyenvalle, Daniel Chappard
Disuse induces a rapid bone loss in humans and animals; hypodynamia/sedentarity is now recognized as a risk factor for osteoporosis. Hypodynamia also decreases bone mass but its effects are largely unknown and only few animal models have been described. Hypodynamic chicken is recognized as a suitable model of bone loss but the effects on the quality have not been fully explored. We have used ten chickens bred in a large enclosure (FREE group); ten others were confined in small cages with little space to move around (HYPO group)...
February 3, 2017: Calcified Tissue International
Jing Li, Xue-Hui Zhang, Ben-Cang Cui, Yuan-Hua Lin, Xu-Liang Deng, Ming Li, Ce-Wen Nan
OBJECTIVE: The aim of this study was to evaluate the microstructure and mechanical behavior of polymer-infiltrated zirconia ceramics as a function of pre-sintering temperature (1000-1150°C). METHODS: Polymer-infiltrated zirconia ceramics were prepared by combining the porous zirconia networks and polymer through infiltration and polymerization. XRD was employed to determine phase structure. The microstructure and fracture mechanism were observed by SEM. Flexural strength and fracture toughness were measured by three-point bending method and single-edge-notched beam method, respectively...
January 31, 2017: Journal of Dentistry
Chien-Jen Tang, Cheng-Chung Jaing, Chuen-Lin Tien, Wei-Chiang Sun, Shih-Chin Lin
Silicon oxynitride films were deposited by reactive pulsed magnetron sputtering. The optical, structural, and mechanical properties of silicon oxynitride films with different nitrogen proportions were analyzed via spectroscopy, atomic force microscopy, Twyman-Green interferometer, and nanoindentation. The refractive indices of the silicon oxynitride films were adjusted from 1.487 to 1.956 with the increase in nitrogen proportions. The surface roughness decreased from 1.33 to 0.97 nm with the increase in nitrogen proportions...
February 1, 2017: Applied Optics
Naohiko Kawamura, Masahiro Iijima, Shuich Ito, William A Brantley, Satish B Alapati, Takeshi Muguruma, Kyotaro Kawaguchi, Takashi Saito, Itaru Mizoguchi
In this study, wear and inhibition of enamel demineralization by resin-based coating materials were investigated. Seven commercially available coating materials, with and without fillers, were used. A mechanical wear test was performed, and the specimens were then examined with a scanning electron microscope. Hardness and elastic modulus measurements for each material were obtained by nanoindentation testing. Thin layers of each material were applied on human enamel surfaces, which were subjected to alternating immersion in demineralizing and remineralizing solutions...
February 1, 2017: European Journal of Oral Sciences
Cheng Zeng, Sven Moller-Tank, Aravind Asokan, Bogdan Dragnea
Recombinant adeno-associated virus (AAV) is a promising gene therapy vector. To make progress in this direction, the relationship between the characteristics of the genomic cargo and the capsid stability must be understood in detail. The goal of this study is to determine the role of the packaged vector genome in the response of AAV particles to mechanical compression and adhesion to a substrate. Specifically, we used atomic force microscopy to compare the mechanical properties of empty AAV serotype 2 (AAV2) capsids and AAV2 vectors packaging single-stranded DNA or self-complementary DNA...
February 14, 2017: Journal of Physical Chemistry. B
Olha Shpotyuk, Stanislaw Adamiak, Elvira Bezvushko, Jozef Cebulski, Maryana Iskiv, Oleh Shpotyuk, Valentina Balitska
Light-curing volumetric shrinkage in dimethacrylate-based dental resin composites Dipol® is examined through comprehensive kinetics research employing nanoindentation measurements and nanoscale atomic-deficient study with lifetime spectroscopy of annihilating positrons. Photopolymerization kinetics determined through nanoindentation testing is shown to be described via single-exponential relaxation function with character time constants reaching respectively 15.0 and 18.7 s for nanohardness and elastic modulus...
December 2017: Nanoscale Research Letters
Andrea Knöller, Christian P Lampa, Felix von Cube, Tingying Helen Zeng, David C Bell, Mildred S Dresselhaus, Zaklina Burghard, Joachim Bill
Nature has evolved hierarchical structures of hybrid materials with excellent mechanical properties. Inspired by nacre's architecture, a ternary nanostructured composite has been developed, wherein stacked lamellas of 1D vanadium pentoxide nanofibres, intercalated with water molecules, are complemented by 2D graphene oxide (GO) nanosheets. The components self-assemble at low temperature into hierarchically arranged, highly flexible ceramic-based papers. The papers' mechanical properties are found to be strongly influenced by the amount of the integrated GO phase...
January 19, 2017: Scientific Reports
Benjamin P J Hasseldine, Chao Gao, Joseph M Collins, Hyun-Do Jung, Tae-Sik Jang, Juha Song, Yaning Li
The common millet (Panicum miliaceum) seedcoat has a fascinating complex microstructure, with jigsaw puzzle-like epidermis cells articulated via wavy intercellular sutures to form a compact layer to protect the kernel inside. However, little research has been conducted on linking the microstructure details with the overall mechanical response of this interesting biological composite. To this end, an integrated experimental-numerical-analytical investigation was conducted to both characterize the microstructure and ascertain the microscale mechanical properties and to test the overall response of kernels and full seeds under macroscale quasi-static compression...
January 6, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Yomna E Saleh, Mohamed A Gepreel, Nageh K Allam
Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation...
January 12, 2017: Scientific Reports
Anaïs Sadoun, Pierre-Henri Puech
Atomic force microscopy (AFM) is an invaluable tool to investigate the structure of biological material surfaces by imaging them at nanometer scale in physiological conditions. It can also be used to measure the forces and mechanics from single molecule interaction to cell-cell adhesion. Here, we present a methodology that allows to quantify cell elastic properties (using the Young modulus) and cell membrane tension modulated by CD95/cl-CD95L interactions by coupling nanoindentation and membrane tube pulling using suitably decorated AFM levers...
2017: Methods in Molecular Biology
Subramaniyan Vasanthavel, Brian Derby, Sanjeevi Kannan
Partially stabilized tetragonal zirconia (t-ZrO2) is of particular interest for hard tissue replacements. Aging-related failures of the ceramic associated with the gradual transformation from t-ZrO2 to m-ZrO2 (monoclinic zirconia) can lead to its premature removal from the implant site. In addition, monitoring the satisfactory performance of the implant throughout its lifespan without invasive techniques is a challenging task. The magnetic resonance imaging (MRI) contrast ability of dysprosium (Dy(3+)) is well-established...
January 6, 2017: Inorganic Chemistry
Mads S Bergholt, Jean-Philippe St-Pierre, Giovanni S Offeddu, Paresh A Parmar, Michael B Albro, Jennifer L Puetzer, Michelle L Oyen, Molly M Stevens
Tissue architecture is intimately linked with its functions, and loss of tissue organization is often associated with pathologies. The intricate depth-dependent extracellular matrix (ECM) arrangement in articular cartilage is critical to its biomechanical functions. In this study, we developed a Raman spectroscopic imaging approach to gain new insight into the depth-dependent arrangement of native and tissue-engineered articular cartilage using bovine tissues and cells. Our results revealed previously unreported tissue complexity into at least six zones above the tidemark based on a principal component analysis and k-means clustering analysis of the distribution and orientation of the main ECM components...
December 28, 2016: ACS Central Science
Muhammad Sohail Zafar
OBJECTIVE: The aim of the current study is to analyze the surface profiles of healthy and periodontal-treated roots. In addition, manual and ultrasonic instrumentation methods have been compared in terms of surface mechanical properties of root surfaces including surface roughness, hardness, and elastic modulus. MATERIALS AND METHODS: This study was conducted using extracted teeth that were randomly divided into two study groups (1 and 2). Root planing was performed using either Gracey curettes (Group 1) or ultrasonic scaler (Group 2)...
October 2016: European Journal of Dentistry
Mikhail Burke, Ayelet Atkins, Alex Kiss, Margarete Akens, Albert Yee, Cari Whyne
The negative impact of metastases on the mechanical performance of vertebral bone is often attributed to reduced bone density and/or compromised architecture. However limited characterization has been done on the impact of metastasis on the mineralization of bone tissue and resulting changes in material behaviour. This study aimed to evaluate the impact of metastasis on micro and nano scale characteristics of the mineral phase of bone, specifically mineral crystal growth, homogeneity of mineralization and changes in intrinsic material properties...
December 23, 2016: Journal of the Mechanical Behavior of Biomedical Materials
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