Variation in mechanical and structural properties of enamel in primate molars

Mechanical properties of enamel are known to vary across molar crowns in some primates, but the association of this variation with phylogeny, structural properties and tribological behaviour is not well understood. In this study, 20 molars from a range of primate taxa (n=15) were studied using nanoindentation, micro-CT scanning, and SEM imaging. After micro-CT scanning, teeth were sectioned in the lingual-buccal plane through the mesial cusps. Five positions (buccal lateral, buccal cuspal, occlusal middle, lingual cuspal, lingual lateral) were studied in three locations (inner, middle, outer enamel regions). The results show middle enamel had the highest hardness and elastic modulus values in all positions. 'Non-functional' molar sides (lingual in lower molars and buccal in upper molars) had higher hardness values than their 'functional' counterparts. Increase in prism size was associated with a decrease in hardness in some tooth positions, and mineral density showed a significant relationship with elastic modulus values. Variation in enamel structure variation (e.g., enamel Schmelzmuster, Hunter-Schreger band thickness), may also be crucial in explaining variation in mechanical properties, with decussation zones associated with higher mechanical properties values. Primate enamel is not a homogeneous material, with variation in mechanical and structural properties across the crown likely associated with functional differences and variation in force distribution. Overall structural and mechanical patterns were similar in the primate species studied despite substantial differences in diet, suggesting these properties are potentially evolutionary conserved.

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Microstructure and Mechanical Properties of Chromium Carbide Coatings Deposited by Magnetron Sputtering Technique

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.397.118 ◽

2019 ◽

Vol 397 ◽

pp. 118-124

Author(s):

Linda Aissani ◽

Khaoula Rahmouni ◽

Laala Guelani ◽

Mourad Zaabat ◽

Akram Alhussein

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

Magnetron Sputtering ◽

Structural Properties ◽

Annealing Temperature ◽

Diffusion Mechanism ◽

X Ray Diffraction ◽

Chromium Carbides ◽

X Ray ◽

Mechanical And Structural Properties

From the hard and anti-corrosions coatings, we found the chromium carbides, these components were discovered by large studies; like thin films since years ago. They were pointed a good quality for the protection of steel, because of their thermal and mechanical properties for this reason, it was used in many fields for protection. Plus: their hardness and their important function in mechanical coatings. The aim of this work joins a study of the effect of the thermal treatment on mechanical and structural properties of the Cr/steel system. Thin films were deposited by cathodic magnetron sputtering on the steel substrates of 100C6, contain 1% wt of carbon. Samples were annealing in vacuum temperature interval between 700 to 1000 °C since 45 min, it forms the chromium carbides. Then pieces are characterising by X-ray diffraction, X-ray microanalysis and scanning electron microscopy. Mechanical properties are analysing by Vickers test. The X-ray diffraction analyse point the formation of the Cr7C3, Cr23C6 carbides at 900°C; they transformed to ternary carbides in a highest temperature, but the Cr3C2 doesn’t appear. The X-ray microanalysis shows the diffusion mechanism between the chromium film and the steel sample; from the variation of: Cr, Fe, C, O elements concentration with the change of annealing temperature. The variation of annealing temperature shows a clean improvement in mechanical and structural properties, like the adhesion and the micro-hardness.

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Newly Formed Bone around Implanted New Titanium Alloy: Ti-15%Zr-4%Nb-4%Ta

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.361-363.661 ◽

2007 ◽

Vol 361-363 ◽

pp. 661-664

Author(s):

Hiroshi Nakada ◽

Yasuko Numata ◽

Taketoshi Suwa ◽

Y. Okazaki ◽

Racquel Z. LeGeros ◽

...

Keyword(s):

Mechanical Properties ◽

Bone Mineral Density ◽

Titanium Alloy ◽

Surface Treatment ◽

Bone Mineral ◽

Ti Alloy ◽

Micro Ct ◽

Mineral Density ◽

Biological Safety ◽

Biological Performance

We have developed a new Ti alloy, Ti-15%Zr-4%Nb-4%Ta alloy (Ti-15-4-4) that showed higher biological safety and mechanical properties than the currently used Ti-6%Al-4%V alloy. The purpose of this study is to determine the biological performance of the new alloy. Ti-15-4-4 implants (machined or blasted) were placed in surgically created defects in rabbit femurs. The rabbits were sacrificed after 4, 8, 16, 24 and 48 weeks. Bone mineral density (BMD) and area of newly formed bone around the implants were measured using micro-CT. Results showed that the Ti-15-4-4 alloy is biocompatible and forms new bone around the Ti-15-4-4 implant, regardless of the surface treatment. The BMD and area of newly formed bone around the blasted implant surfaces were significantly greater than those around the machined surfaces. These results indicate that the new Ti-15-4-4 alloy has a potential for use as implants and has the advantage of improved mechanical properties described in earlier studies.

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Ex Vivo Dermis Mechanical Behavior in Relation to Decellularization Treatment Length

The Open Biomedical Engineering Journal ◽

10.2174/1874120701610010034 ◽

2016 ◽

Vol 10 (1) ◽

pp. 34-42 ◽

Cited By ~ 7

Author(s):

Mara Terzini ◽

Cristina Bignardi ◽

Carlotta Castagnoli ◽

Irene Cambieri ◽

Elisabetta M. Zanetti ◽

...

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Sodium Hydroxide ◽

Structural Properties ◽

Structural Integrity ◽

Ex Vivo ◽

Tensile Tests ◽

Treatment Length ◽

Native Tissue ◽

The Impact

Background: The dermis is a commonly used source tissue for biologic scaffolds; all cellular and nuclear materials need to be removed to limit the inflammatory immune response by the host organism. The decellularization is critical because it must preserve the structural integrity of the extracellular matrix. This work has analyzed a decellularization procedure commonly followed for the dermal tissue that is a chemical treatment with sodium hydroxide. The goal of this work is to identify the optimal treatment length on the basis of structural properties. Methods: Tensile tests have been performed on the native tissue and on tissues decellularized for 1-7 weeks in sodium hydroxide. The collected data have been analyzed through Tukey-Kramer test to assess if the mechanical properties (ultimate tensile stress and elastic modulus) of decellularized tissues were significantly different from the properties of the native tissue. These tests have been performed on specimens cut along two orthogonal directions (parallel and perpendicular to Langer’s lines). Results: The decellularization treatment performed with sodium hydroxide in general weakens the tissue: both the ultimate stress and the elastic modulus get lower. The structural properties along Langer lines orientation are more strongly impacted, while the structural properties orthogonal to Langer lines can be preserved with an optimal duration of the decellularization treatment that is 5-6 weeks. Conclusion: The duration of the decellularization treatment is critical not only to reach a complete decellularization, but also to preserve the mechanical properties of the tissue; 5-6 week treatment performed with sodium hydroxide allows preserving the mechanical properties of the native tissue perpendicularly to Langer lines orientation, and minimizing the impact of the decellularization process on the mechanical properties along the Langer lines orientation.

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Mechanical and Structural Properties of TiC and TiCN Thin Films Grown by RF Sputtering

MRS Proceedings ◽

10.1557/proc-778-u6.13 ◽

2003 ◽

Vol 778 ◽

Cited By ~ 2

Author(s):

A. Mani ◽

P. Aubert ◽

H. Khodja ◽

P. Houdy

Keyword(s):

Thin Films ◽

Mechanical Properties ◽

Titanium Carbide ◽

Partial Pressure ◽

Compressive Stress ◽

Structural Properties ◽

Rf Sputtering ◽

Maximum Value ◽

Mechanical And Structural Properties ◽

Sputtering Pressure

AbstractTiC and TiCN thin films were deposited by RF sputtering from a TiC target. For TiC thin films, the various sputtering pressure were carried out in order to observe the influence of this parameter on structural and mechanical properties. The experimental results show that a pressure of 1 Pa is necessary to obtain stoichiometric films with <111> texture. Lower pressures induce the formation of distorted titanium carbide, while RBS spectra show that the Ti/C ratio is constant for all these samples. Both the compressive stress and the hardness exhibited a maximum value for the lowest pressures. For TiCN thin films, the composition and the hardness were investigated as function of the N2 partial pressure (PN2 = 3% to 70%).

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Mechanical Properties of the Rabbit Patellar Tendon

Journal of Biomechanical Engineering ◽

10.1115/1.2891392 ◽

1992 ◽

Vol 114 (3) ◽

pp. 332-337 ◽

Cited By ~ 59

Author(s):

N. Yamamoto ◽

K. Hayashi ◽

H. Kuriyama ◽

K. Ohno ◽

K. Yasuda ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Structural Properties ◽

Patellar Tendon ◽

Tensile Tests ◽

The Other ◽

Central Portion ◽

Mechanical And Structural Properties ◽

Lateral Portion

The mechanical and structural properties of the patellar tendon fascicle-bone units of rabbit knees were determined by tensile tests, particularly focusing on their local differences. There were no significant differences in the strains measured by a video dimension analyzer among the proximal, middle, and distal regions of the central portion of tendon. The mechanical properties of the medial portion agreed well with those of the central portion. However, significant differences were observed in the tensile strength between the lateral and the other two portions: the tensile strength of the lateral portion was about 16 percent larger than those in the other portions.

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Compressive axial mechanical properties of rat bone as functions of bone volume fraction, apparent density and micro-ct based mineral density

Journal of Biomechanics ◽

10.1016/j.jbiomech.2009.10.047 ◽

2010 ◽

Vol 43 (5) ◽

pp. 953-960 ◽

Cited By ~ 54

Author(s):

Esther Cory ◽

Ara Nazarian ◽

Vahid Entezari ◽

Vartan Vartanians ◽

Ralph Müller ◽

...

Keyword(s):

Mechanical Properties ◽

Apparent Density ◽

Volume Fraction ◽

Bone Volume ◽

Micro Ct ◽

Mineral Density ◽

Bone Volume Fraction ◽

Rat Bone

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A MODIFIEDTWIST-SPINNING TECHNOLOGY:THREE-ROVING YARN SPINNING

TEXTEH Proceedings ◽

10.35530/tt.2019.18 ◽

2019 ◽

Vol 2019 ◽

pp. 82-85 ◽

Cited By ~ 1

Author(s):

Murat DEMIR ◽

Musa KILIC

Keyword(s):

Mechanical Properties ◽

Structural Properties ◽

Production System ◽

Raw Material ◽

Conventional System ◽

Ring Spinning ◽

Mechanical And Structural Properties ◽

Yarn Production ◽

Working Principle ◽

New System

Ring spinning is one of the oldest and most widely used spinning technology. Recently, many alternative spinning technologies have been introduced. Some of these technologies work on completely different working principle while some of them were developed from conventional system with some modifications. Siro- spun technology which two strands are fed into drafting zone simultaneously is one of the systems that developed from conventional ring spinning. This study focuses on development of three-roving yarn production system that was inspired from siro-spun technology. Roving funnel and delivery cylinder used in siro-spun technology were redesigned for three-roving yarn production and attached on conventional system. Three-roving yarns produced in ring spinning machine were compared with three plied yarns in terms of physical, mechanical and structural properties. For better assessment of this new system, different raw material types were used in yarn production. Results showed that three-roving yarns have better hairiness values and similar mechanical properties for all raw material types. However, unevenness still needs to be improved by further developments on this new system.

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EFFECT OF FILTER COIL CURRENT ON PROPERTIES OF nc-TiC/a-C:H NANOCOMPOSITE FILM PREPARED BY DUAL PLASMA TECHNIQUE

Surface Review and Letters ◽

10.1142/s0218625x0701072x ◽

2007 ◽

Vol 14 (06) ◽

pp. 1143-1148 ◽

Cited By ~ 1

Author(s):

YAOHUI WANG ◽

XU ZHANG ◽

XIANYING WU ◽

HUIXING ZHANG ◽

XIAOJI ZHANG

Keyword(s):

Mechanical Properties ◽

Elastic Modulus ◽

Structural Properties ◽

Deposition Rate ◽

Nanocomposite Film ◽

Elastic Recovery ◽

Coil Current ◽

Plasma Technique ◽

High Elastic Modulus ◽

Unusual Combination

Nanocomposite nc-TiC / a-C : H films, with an unusual combination of superhardness and high elastic recovery, are prepared by using dual plasma technique. The effect of the filter coil current on the compositional and structural properties of the nc-TiC / a-C : H films has been investigated. It is found that the deposition rate and the composition of nc-TiC / a-C : H films could be changed by varying the filter coil current. Fortunately, by selecting the proper value of the filter coil current, 2.5 A, one can remarkably enhance the mechanical properties of the film, such as the superhardness (66.4 GPa), the high elastic modulus (510 GPa), and the high elastic recovery (83.3%).

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