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Dongwei Hou, Guoping Zhang, Rohit Raj Pant, Zhongxin Wei, Shuilong Shen
Clay-based nanostructured multilayers, such as clay-polymer multilayers and clay-oxide multilayers, have attracted growing attention owing to their remarkable mechanical properties and promising application in various fields. In this paper, synthesis of a new kind of nanostructured clay-oxide multilayers by layer-by-layer self-assembly was explored. Nano-mechanical characterization of 18 clay-based multilayer samples, prepared under as-deposited (i.e., air-dried) and annealing conditions at 400 °C/600 °C with different precursor cations and multilayer structure, were carried out using nanoindentation testing, atomic force microscopy (AFM), and X-ray diffraction (XRD)...
November 8, 2016: Nanomaterials
Amadou Ouattara, Diana Cooke, Raj Gopalakrishnan, Tsang-Hai Huang, Gene P Ables
Methionine restriction (MR) extends the lifespan of a wide variety of species, including rodents, drosophila, nematodes, and yeasts. MR has also been demonstrated to affect the overall growth of mice and rats. The objective of this study was to evaluate the effect of MR on bone structure in young and aged male and female C57BL/6J mice. This study indicated that MR affected the growth rates of males and young females, but not aged females. MR reduced volumetric bone mass density (vBMD) and bone mineral content (BMC), while bone microarchitecture parameters were decreased in males and young females, but not in aged females compared to control-fed (CF) mice...
December 2016: Bone Reports
Jingzu Hao, Ying Li, Baoe Li, Xiaolin Wang, Haipeng Li, Shimin Liu, Chunyong Liang, Hongshui Wang
Hybrid micro-nanostructure implant surface was produced on titanium (Ti) surface by acid etching and anodic oxidation to improve the biological and mechanical properties. The biological properties of the micro-nanostructure were investigated by simulated body fluid (SBF) soaking test and MC3T3-E1 cell co-culture experiment. The cell proliferation, spreading, and bone sialoprotein (BSP) gene expression were examined by MTT, SEM, and reverse transcription-polymerase chain reaction (RT-PCR), respectively. In addition, the mechanical properties were evaluated by instrumented nanoindentation test and friction-wear test...
March 20, 2017: Applied Biochemistry and Biotechnology
Chung-Chuan Lai, Cecilia Goyenola, Esteban Broitman, Lars-Åke Näslund, Hans Hogberg, Lars Hultman, Gueorgui Gueorguiev, Johanna Rosen
A theoretical and experimental study on the growth and properties of a ternary carbon-based material, CS<sub><i>x</i></sub>F<sub><i>y</i></sub>, synthesized from SF<sub>6</sub> and C as primary precursors is reported. The synthetic growth concept was applied to model the possible species resulting from the fragmentation of SF<sub>6</sub> molecules and the recombination of S-F fragments with atomic C. The possible species were further evaluated for their contribution to the film growth...
March 20, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
R Abram, D Chrobak, R Nowak
The Letter concerns surface nanodeformation of Si crystal using atomistic simulation. Our results account for both the occurrence and absence of pop-in events during nanoindentation. We have identified two distinct processes responsible for indentation deformation based on load-depth response, stress-induced evolution of crystalline structure and surface profile. The first, resulting in a pop-in, consists of the extrusion of the crystalline high pressure Si-III/XII phase, while the second, without a pop-in, relies on a flow of amorphized Si to the crystal surface...
March 3, 2017: Physical Review Letters
Lizhe Qin, Lanying Lin, Feng Fu, Mizi Fan
Emulsion polymer isocyanate (EPI) and urea-formaldehyde (UF) were selected as typical resin systems to investigate the microstructure of wood-adhesive interphases by fluorescence microscopy (FM) and confocal laser scanning microscopy (CLSM). Further, a quantitative micromechanical analysis of the interphases was conducted using nanoindentation. The FM results showed that the UF resin could penetrate the wood to a greater extent than the EPI resin, and that the average penetration depth for these two resin systems was higher in the case of latewood...
March 15, 2017: Microscopy and Microanalysis
Tianlong Zhang, Jiazi Gao, Juan Fang, He Gong
This study aimed to explore the effects of additional weight bearing in combination with low-magnitude high-frequency vibration (LMHFV; 45 Hz, 0.3 g) on bone quality. One hundred twenty rats were randomly divided into ten groups; namely, sedentary (SED), additional weight bearing in which the rat wears a backpack whose weight is x% of the body weight (WBx; x = 5, 12, 19, 26), basic vibration (V), and additional weight bearing in combination with LMHFV in which the rat wears a backpack whose weight is x% of the body weight (Vx; x = 5, 12, 19, 26)...
March 14, 2017: Journal of Bone and Mineral Metabolism
Raul Zazpe, Jan Prikryl, Viera Gärtnerova, Katerina Nechvilova, Ludvik Benes, Lukas Strizik, Ales Jäger, Markus Bosund, Hanna Sopha, Jan M Macak
We report on a very significant enhancement of the thermal, chemical, and mechanical stability of self-organized TiO2 nanotubes layers, provided by thin Al2O3 coatings of different thicknesses prepared by atomic layer deposition (ALD). TiO2 nanotube layers coated with Al2O3 coatings exhibit significantly improved thermal stability as illustrated by the preservation of the nanotubular structure upon annealing treatment at high temperatures (870 °C). In addition, a high anatase content is preserved in the nanotube layers against expectation of the total rutile conversion at such a high temperature...
March 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Abby E Peters, Eithne J Comerford, Sophie Macaulay, Karl T Bates, Riaz Akhtar
Tissue material properties are crucial to understanding their mechanical function, both in healthy and diseased states. However, in certain circumstances logistical limitations can prevent testing on fresh samples necessitating one or more freeze-thaw cycles. To date, the nature and extent to which the material properties of articular cartilage are altered by repetitive freezing have not been explored. Therefore, the aim of this study is to quantify how articular cartilage mechanical properties, measured by nanoindentation, are affected by multiple freeze-thaw cycles...
March 7, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Frances Y Su, Eric A Bushong, Thomas J Deerinck, Kyungah Seo, Steven Herrera, Olivia A Graeve, David Kisailus, Vlado A Lubarda, Joanna McKittrick
This paper explores the structure, composition, and mechanical properties of porcupine fish spines for the first time. The spine was found to be composed of nanocrystalline hydroxyapatite, protein (collagen), and water using X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. Microstructures have mineralized fibrillar sheets in the longitudinal direction and in a radial orientation in the transverse direction that were observed using light and electron microscopy. Based on the images, the hierarchical structure of the spine shows both concentric and radial reinforcement...
February 28, 2017: Journal of the Mechanical Behavior of Biomedical Materials
Thayanne Monteiro Ramos-Oliveira, Camila Vieira Silva, Paula Mendes Acatauassu Nunes, Cecília Pedroso Turssi, Peter Rechmann, Patricia Moreira de Freitas
This in situ study aimed to investigate the effect of a tin-containing fluoride solution in preventing enamel erosion. Also, its effects on the partly demineralized zone were assessed for the first time. Thirteen volunteers participated in this 2-phase study, wearing removable intra-oral appliances containing four sterilized bovine enamel slabs, for 8 days, where 2 treatment protocols were tested using samples in replicas (n = 13): CO - no treatment (negative control) and FL - AmF/NaF/SnCl2 solution (500 ppm F-, 800 ppm Sn2+, pH = 4...
March 6, 2017: Brazilian Oral Research
Weidong Wang, Longlong Li, Chenguang Yang, Rafael A Soler-Crespo, Zhaoxu Meng, Minglin Li, Xu Zhang, Sinan Keten, Horacio D Espinosa
Molecular dynamics simulations on nanoindentation of circular monolayer molybdenum disulfide (MoS2) film are carried out to elucidate the deformation and failure mechanisms. Typical force-deflection curves are obtained, and in-plane stiffness of MoS2 is extracted according to a continuum mechanics model. The measured in-plane stiffness of monolayer MoS2 is about 182 ± 14 N m(-1), corresponding to an effective Young's modulus of 280 ± 21 GPa. More interestingly, at a critical indentation depth, the loading force decreases sharply and then increases again...
April 21, 2017: Nanotechnology
Lucas Colabella, Ariel Alejandro Ibarra Pino, Josefina Ballarre, Piotr Kowalczyk, Adrián Pablo Cisilino
The FFT based method, originally introduced by Moulinec and Suquet in 1994 has gained popularity for computing homogenized properties of composites. In this work, the method is used for the computational homogenization of the elastic properties of cancellous bone. To the authors' knowledge, this is the first study where the FFT scheme is applied to bone mechanics. The performance of the method is analyzed for artificial and natural bone samples of two species: bovine femoral heads and implanted femurs of Hokkaido rats...
March 7, 2017: International Journal for Numerical Methods in Biomedical Engineering
Hui Xie, Hao Zhang, Danish Hussain, Xianghe Meng, Jianmin Song, Lining Sun
We report high-resolution multiparametric kelvin probe force microscopy (MP-KPFM) measurements for the simultaneous quantitative mapping of the contact potential difference (CPD) and nanomechanical properties of the sample in single-pass mode. This method combines functionalities of the force-distance-based atomic force microscopy and amplitude-modulation (AM) KPFM to perform measurements in single-pass mode. During the tip-sample approach-and-retract cycle, nanomechanical measurements are performed for the retract part of nanoindentation, and the CPD is measured by the lifted probe with a constant tip-sample distance...
March 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Jaime J Hernández, Miguel A Monclús, Iván Navarro-Baena, Felipe Viela, Jon M Molina-Aldareguia, Isabel Rodríguez
This paper presents a multifunctional polymer surface that provides superhydrophobicity and self-cleaning functions together with an enhancement in mechanical and electrical performance. These functionalities are produced by nanoimprinting high aspect ratio pillar arrays on polymeric matrix incorporating functional reinforcing elements. Two distinct matrix-filler systems are investigated specifically, Carbon Nanotube reinforced Polystyrene (CNT-PS) and Reduced Graphene Oxide reinforced Polyvinylidene Difluoride (RGO-PVDF)...
March 6, 2017: Scientific Reports
Longhai Li, Ce Guo, Shun Xu, Xin Li, Cheng Han
Microstructure and nanoindentation properties of the mouthparts for the skillful driller Cyrtotrachelus longimanus are presented. The composition and morphological examinations are made using light, fluorescent, scanning electron microscopy, and Energy Disperse Spectroscopy, respectively. Nanoindentation was carried out to measure the elastic modulus and the hardness of mouthparts. The hardness and modulus for "dry" samples is 0.202 ± 0.065 and 8.604 ± 0.838 GPa, respectively, and the values of "fresh" ones is 0...
February 28, 2017: Microscopy Research and Technique
X Wendy Gu, Xingchen Ye, David M Koshy, Shraddha Vachhani, Peter Hosemann, A Paul Alivisatos
Large, freestanding membranes with remarkably high elastic modulus (>10 GPa) have been fabricated through the self-assembly of ligand-stabilized inorganic nanocrystals, even though these nanocrystals are connected only by soft organic ligands (e.g., dodecanethiol or DNA) that are not cross-linked or entangled. Recent developments in the synthesis of polymer-grafted nanocrystals have greatly expanded the library of accessible superlattice architectures, which allows superlattice mechanical behavior to be linked to specific structural features...
February 27, 2017: Proceedings of the National Academy of Sciences of the United States of America
Ke Chen, Jin Ding, Shuhao Zhang, Xuke Tang, Yonghai Yue, Lin Guo
Creating lightweight engineering materials combining high strength and great toughness remains a significant challenge. Despite possessing-enhanced strength and stiffness, bioinspired/polymeric materials usually suffer from clearly reduced extensibility and toughness when compared to corresponding bulk polymer materials. Herein, inspired by tiny amounts of various inorganic impurities for mechanical improvement in natural materials, we present a versatile and effective metal ion (M(n+))-based synergic cross-linking (MSC) strategy incorporating eight types of metal ions into material bulks that can drastically enhance the tensile strength (∼24...
March 28, 2017: ACS Nano
P Nandha Kumar, S Kannan
The sequential formation of β-Ca3(PO4)2/TiO2 composites with assorted ratios synthesized from the solution precursors is described. The phase evolution of the synthesized powders to yield a composite during progressive heat treatments is determined through a set of analytical techniques. Investigation reveals the initial crystallization of apatite and anatase TiO2 (a-TiO2) mixtures at <800 °C. β-Ca3(PO4)2 crystallizes at ∼800 °C and its subsequent stability is retained until 1300 °C. Besides, a gradual phase transition of a- → rutile TiO2 (r-TiO2) transpires in the range of 800-1000 °C before the complete r-TiO2 transformation accomplishes at 1100 °C...
February 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Raquel Osorio, Camilo Andrés Alfonso-Rodríguez, Estrella Osorio, Antonio L Medina-Castillo, Miguel Alaminos, Manuel Toledano-Osorio, Manuel Toledano
OBJECTIVE: The objective of the study is characterization of novel calcium and zinc-loaded electrospun matrices to be used for periodontal regeneration. MATERIALS AND METHODS: A polymethylmetacrylate-based membrane was calcium or zinc loaded. Matrices were characterized morphologically by atomic force and scanning electron microscopy and mechanically probed by a nanoindenter. Biomimetic calcium phosphate precipitation on polymeric tissues was assessed. Cell viability tests were performed using oral mucosa fibroblasts...
February 18, 2017: Clinical Oral Investigations
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