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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
Antonios L Theocharopoulos, Andrew J Bushby, Ken My P'ng, Rory M Wilson, K Elizabeth Tanner, Michael J Cattell
PURPOSE: The aim of this study was to test the modulus of elasticity (E) across the interfaces of yttria stabilized zirconia (YTZP) / veneer multilayers using nanoindentation. MATERIALS AND METHODS: YTZP core material (KaVo-Everest, Germany) specimens were either coated with a liner (IPS e.max ZirLiner, Ivoclar-Vivadent) (Type-1) or left as-sintered (Type-2) and subsequently veneered with a pressable glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent). A 5 µm (nominal tip diameter) spherical indenter was used with a UMIS CSIRO 2000 (ASI, Canberra, Australia) nanoindenter system to test E across the exposed and polished interfaces of both specimen types...
December 2016: Journal of Advanced Prosthodontics
Zsuzsanna Vörös, Gabriella Csík, Levente Herényi, Miklós S Z Kellermayer
Viruses are nanoscale infectious agents constructed of a proteinaceous capsid that protects the packaged genomic material. Nanoindentation experiments using atomic force microscopy have, in recent years, provided unprecedented insight into the elastic properties, structural stability and maturation-dependent mechanical changes in viruses. However, the dynamics of capsid behavior are still unresolved. Here we used high-resolution nanoindentation experiments on mature, DNA-filled T7 bacteriophage particles. The elastic regime of the nanoindentation force trace contained discrete, stepwise transitions that cause buckling of the T7 capsid with magnitudes that are integer multiples of ∼0...
December 23, 2016: Nanoscale
Mohit Parekh, Alessandro Ruzza, Rosa Di Mundo, Stefano Ferrari, Giuseppina Recchia, Hossein Elbadawy, Giuseppe Carbone, Diego Ponzin
PURPOSE: To investigate the adhesive and stiffness properties of prestripped Descemet membrane endothelial keratoplasty (DMEK) lenticules in different preservation conditions (with and without dextran). METHODS: The study included 3 conditions: (C1) tissues collected from tissue culture media (TCM), stripped and preserved in TCM; (C2) tissues collected from transport media (TM) (TCM supplemented with 6% dextran T-500), stripped and preserved in TM; and (C3) tissues collected from TCM, stripped and preserved in TM...
November 25, 2016: European Journal of Ophthalmology
Chaiyapat Tangpatjaroen, David Grierson, Steve Shannon, Joseph E Jakes, Izabela Szlufarska
Nanoscale, single-asperity wear of single-crystal silicon carbide (sc-SiC) and nanocrystalline silicon carbide (nc-SiC) is investigated using single-crystal diamond nanoindenter tips and nanocrystalline diamond atomic force microscopy (AFM) tips under dry conditions, and the wear behavior is compared to that of single-crystal silicon with both thin and thick native oxide layers. We discovered a transition in the relative wear resistance of the SiC samples compared to that of Si as a function of contact size...
January 18, 2017: ACS Applied Materials & Interfaces
Mohammad Humood, Shuang Qin, Yixuan Song, Kyriaki Polychronopoulou, Youfeng Zhang, Jaime C Grunlan, Andreas A Polycarpou
Graphene is a versatile composite reinforcement candidate due to its strong mechanical, tunable electrical and optical properties, and chemical stability. However, one drawback is the weak interfacial bonding, which results in weak adhesion to substrates. This could be overcome by adding polymer layers to have stronger adherence to the substrate and between graphene sheets. These multilayer thin films were found to have lower resistance to lateral scratch forces when compared to other reinforcements such as polymer/clay nanocomposites...
December 19, 2016: ACS Applied Materials & Interfaces
Aiko Sekita, Aira Matsugaki, Takuya Ishimoto, Takayoshi Nakano
Cancer metastasis to bones increases the risk of fragility fracture by altering bone metabolism and disrupting bone structure. Osteocytes, which organize a dense network that is closely linked with the circumambient matrix, play a key role in regulation of bone microstructure and material properties. The aim of this study was to elucidate the influence of cancer metastasis on the organization of the osteocyte network and collagen/biological apatite (BAp) microstructure in the context of osteocyte/matrix coupling...
December 16, 2016: Journal of Structural Biology
Rakesh Das, Amit Kumar, Anurag Patel, Sahil Vijay, Shashank Saurabh, Navin Kumar
In light of recent focus on the behaviour of the natural structures for revolutionary technological growth, spider web seems to have seized considerable attention of product designer due to its amazing behaviour. In present work, mechanism behind the structural integrity of the spider web along with the materialistic analysis of its constituent silk threads has been extensively investigated. The nanoindentation tool both in static and dynamic mode has been utilized for complete analysis of the mechanical behaviour of the spiral and radial threads separately...
December 13, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Himani Kalita, Pallabi Pal, Santanu Dhara, Amita Pathak
Nanocomposite films of polyvinyl alcohol (PVA) and zirconium phosphate (ZrP)/doped ZrP (doped with Ca, Mg, Ti) nanoparticles have been developed by solvent casting method to assess their potential as matrix material in scaffold-guided tissue engineering application. The prepared ZrP and doped ZrP nanoparticles as well as the nanocomposite films were characterized by various spectroscopic and microscopic techniques. Nanoindentation studies revealed improved nanomechanical properties in the PVA/doped ZrP nanocomposite films (highest for PVA/Ti doped ZrP: hardness=262...
February 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Auezhan Amanov, Soo-Wohn Lee, Young-Sik Pyun
We propose herein a nondestructive surface modification technique called ultrasonic nanocrystalline surface modification (UNSM) to increase the strength and to improve the tribological performance of 316L stainless steel (SS) tubing. Nanocrystallization along nearly the complete tube thickness of 200μm was achieved by UNSM technique that was confirmed by electron backscatter diffraction (EBSD). Nano-hardness of the untreated and UNSM-treated specimens was measured using a nanoindentation. Results revealed that a substantial increase in hardness was obtained for the UNSM-treated specimen that may be attributed to the nanocrystallization and refined grains...
February 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Antonio Boccaccio, Antonio E Uva, Massimiliano Papi, Michele Fiorentino, Marco De Spirito, Giuseppe Monno
Characterisation of the mechanical behaviour of cancer cells is an issue of crucial importance as specific cell mechanical properties have been measured and utilized as possible biomarkers of cancer progression. Atomic force microscopy certainly occupies a prominent place in the field of the mechanical characterisation devices. We developed a hybrid approach to characterise different cell lines (SW620 and SW480) of the human colon carcinoma submitted to nanoindentation measurements. An ad hoc algorithm was written that compares the force-indentation curves experimentally retrieved with those predicted by a finite element model that simulates the nanoindentation process and reproduces the cell geometry and the surface roughness...
January 27, 2017: Nanotechnology
Kshanaprava Dhalsamant, Punyadarshini P Tripathy, Shanker L Shrivastava
BACKGROUND: Desirable quality estimation is an important consumer driver for wider acceptability of mixed-mode solar drying of potatoes in food industries. The aim of this study is to characterize rehydration, colour, texture, nanoindentaion and microstructure of dried potato samples and to establish the influence of pre-drying treatment on above qualities. RESULTS: The water absorption capacity and rehydration ability of solar dried potato were significantly influenced by pretreatment followed by rehydration temperature and sample diameter...
December 16, 2016: Journal of the Science of Food and Agriculture
J Zalesak, J Todt, R Pitonak, A Köpf, R Weißenbacher, B Sartory, M Burghammer, R Daniel, J Keckes
Because of the tremendous variability of crystallite sizes and shapes in nano-materials, it is challenging to assess the corresponding size-property relationships and to identify microstructures with particular physical properties or even optimized functions. This task is especially difficult for nanomaterials formed by self-organization, where the spontaneous evolution of microstructure and properties is coupled. In this work, two compositionally graded TiAlN films were (i) grown using chemical vapour deposition by applying a varying ratio of reacting gases and (ii) subsequently analysed using cross-sectional synchrotron X-ray nanodiffraction, electron microscopy and nanoindentation in order to evaluate the microstructure and hardness depth gradients...
December 1, 2016: Journal of Applied Crystallography
Joo Young Jung, Nadeem Qaiser, Gang Feng, Byung-Il Hwang, Taegeon Kim, Jae Hyun Kim, Seung Min Han
In this study, the size dependent hardness of silver nanowires with a five-fold twin structure was examined using nanoindentation. As the diameter of the nanowires is reduced, the five-fold twin boundaries restrict the dislocation motion, and therefore a size dependent plasticity is expected for these uniquely structured nanowires. The polyol reduction method with modifications was used to synthesize silver nanowires with different diameters in the range of 70 nm to 144 nm. The nanoindentation experiments were performed on silver nanowires deposited on a stiff MgO substrate, and the resulting h, P, and S data were analyzed using the analytical double contact model for nanowire indentation...
January 4, 2017: Physical Chemistry Chemical Physics: PCCP
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