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tensile stress

Marta Girvent Vilarmau, Felipe Ojeda Pérez, Maria José Canto Rivera, Marian Lorente Gascón
INTRODUCTION AND HYPOTHESIS: The aim of the study is to facilitate the suture on the sacral promontory for laparoscopic sacrocolpopexy. We hypothesised that a new method of sacral anchorage using a biosynthetic material, the polyether ether ketone (PEEK) harpoon, might be adequate because of its tensile strength, might reduce complications owing to its well-known biocompatibility, and might shorten the duration of surgery. METHODS: We verified the feasibility of insertion and quantified the stress resistance of the harpoons placed in the promontory in nine fresh cadavers, using four stress tests in each case...
October 17, 2016: International Urogynecology Journal
Jack R Staunton, Wilfred Vieira, King Leung Fung, Ross Lake, Alexus Devine, Kandice Tanner
One of the hallmarks of the malignant transformation of epithelial tissue is the modulation of stromal components of the microenvironment. In particular, aberrant extracellular matrix (ECM) remodeling and stiffening enhances tumor growth and survival and promotes metastasis. Type I collagen is one of the major ECM components. It serves as a scaffold protein in the stroma contributing to the tissue's mechanical properties, imparting tensile strength and rigidity to tissues such as those of the skin, tendons, and lungs...
September 2016: Cellular and Molecular Bioengineering
Jie Fu, Hee Young Kim, Shuichi Miyazaki
In this study a new superelastic Ti-18Zr-4.5Nb-3Sn-2Mo alloy was prepared by adding 2at% of Mo as a substitute for Nb to the Ti-18Zr-11Nb-3Sn alloy, and heat treatment at different temperatures was conducted. The temperature dependence of superelasticity and annealing texture was investigated. Texture showed a dependence of annealing temperature: the specimen annealed at 923K for 0.3ks exhibited {113}β<47¯1>β type texture which was similar to the deformation texture, while specimens annealed at 973, 1073K, and 1173K showed {001}β<110>β type recrystallization texture which was preferable for recovery strain...
September 28, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Gregory J Wright, Matthew C Coombs, R Glenn Hepfer, Brooke J Damon, Thierry H Bacro, Michael K Lecholop, Elizabeth H Slate, Hai Yao
Approximately 30% of temporomandibular joint (TMJ) disorders include degenerative changes to the articular disc, with sex-specific differences in prevalence and severity. Limited tensile biomechanical properties of human TMJ discs have been reported. Stress relaxation tests were conducted on TMJ disc specimens harvested bilaterally from six males and six females (68.9±7.9 years), with step-strain increments of 5%, 10%, 15%, 20% and 30%, at 1% strain-per-second. Stress versus strain plots were constructed, and Young׳s Modulus, Instantaneous Modulus and Relaxed Modulus were determined...
October 6, 2016: Journal of Biomechanics
David Taylor
Experiments and observations were carried out to investigate the response to impact of the shells of the limpet Patella vulgata. Dropped-weight impact tests were conducted, creating damage which usually took the form of a hole in the shell's apex. Similar damage was found to occur naturally, presumably as a result of stones propelled by the sea during storms. Apex holes were usually fatal, but small holes were sometimes repaired, and the repaired shell was as strong as the original, undamaged shell.The impact strength (energy to failure) of shells tested in situ was found to be 3...
October 14, 2016: Journal of Experimental Biology
Sajjad Jafari, R K Singh Raman, Chris H J Davies, Joelle Hofstetter, Peter J Uggowitzer, Jörg F Löffler
Magnesium (Mg) alloys have attracted great attention as potential materials for biodegradable implants. It is essential that an implant material possesses adequate resistance to cracking/fracture under the simultaneous actions of corrosion and mechanical stresses, i.e., stress corrosion cracking (SCC) and/or corrosion fatigue (CF). This study investigates the deformation behaviour of a newly developed high-strength low-alloy Mg alloy, MgZn1Ca0.3 (ZX10), processed at two different extrusion temperatures of 325 and 400°C (named E325 and E400, respectively), under slow strain tensile and cyclic tension-compression loadings in air and modified simulated body fluid (m-SBF)...
September 28, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Jia-Ling Ruan, Nathaniel L Tulloch, Maria V Razumova, Mark Saiget, Veronica Muskheli, Lil Pabon, Hans Reinecke, Michael Regnier, Charles E Murry
BACKGROUNDS: -Tissue engineering enables the generation of functional human cardiac tissue using cells derived in vitro in combination with biocompatible materials. Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes provide a cell source for cardiac tissue engineering; however, their immaturity limits their potential applications. Here we sought to study the effect of mechanical conditioning and electrical pacing on the maturation of hiPSC-derived cardiac tissues. METHODSS: -Cardiomyocytes derived from hiPSCs were used to generate collagen-based bioengineered human cardiac tissue...
October 13, 2016: Circulation
Daniel A Müller, Jess G Snedeker, Dominik C Meyer
BACKGROUND: This is the first study assessing the properties of large-diameter degradable sutures relevant for orthopedic applications over the course of in vitro incubation for 2 months. The data we present here provide guidance to the orthopedic surgeon in predicting the long-term performance of suture materials used everyday in surgical practice. METHODS: Five different absorbable (Vicryl, Maxon, Monocryl, PDS II, Vicryl rapide) and one non-absorbable (Ethibond) suture materials were tested...
October 12, 2016: Journal of Orthopaedic Surgery and Research
Muhamad S Musa, Amir H Milani, Peter Shaw, Gareth Simpson, Peter A Lovell, Elizabeth Eaves, Nigel Hodson, Brian R Saunders
In this study we investigate the structure-mechanical property relationships for nanostructured ionomer films containing ionically crosslinked core-shell polymer nanoparticles based on poly(n-butyl acrylate) (PBA). Whilst nanostructured ionomer films of core-shell nanoparticles have been previously shown to have good ductility [Soft Matter, 2014, 10, 4725], the modulus values were modest. Here, we used BA as the primary monomer to construct core-shell nanoparticles that provided films containing nanostructured polymers with much higher glass transition temperature (Tg) values...
October 4, 2016: Soft Matter
Jinze Li, Honglie Shen, Jieyi Chen, Yufang Li, Jiale Yang
Ge-doped CZTSSe thin films were obtained by covering a thin Ge layer on CZTS precursors, followed by a selenization process. The effect of the Ge layer thickness on the morphologies and structural properties of Ge-doped CZTSSe thin films were studied. It was found that Ge doping could promote grain growth to form a compact thin film. The lattice shrank in the top-half of the film due to the smaller atomic radius of Ge, leading to the formation of tensile stress. According to thermodynamic analysis, Sn was easier to be selenized than Ge...
October 10, 2016: Physical Chemistry Chemical Physics: PCCP
Hao Sun, Sankha Mukherjee, Chandra Veer Singh
Two new graphene allotropes, penta-graphene and phagraphene, have been proposed recently with unique electronic properties, e.g. quasi-direct band gap, direction-dependent Dirac cones and tunable Fermi velocities. However, their mechanical properties have not been fully studied yet. In this work, we have performed extensive density functional theory calculations to evaluate the mechanical properties of these two materials and compared with graphene, graphane, and pentaheptite. Our simulations show that the ultimate tensile strength (UTS) and the strain corresponding to UTS in both penta-graphene and phagraphene are smaller than that of graphene...
September 29, 2016: Physical Chemistry Chemical Physics: PCCP
E B Deerenberg, J Verhelst, S E R Hovius, J F Lange
BACKGROUND: Recurrence is the most important complication of abdominal wall reconstruction. It is possible the repair itself is intact, but bulging or expansion of mesh causes recurrent swelling's of the abdominal wall. CASE SUMMARY: In this report, we present bulging of a polyester mesh due to central pore expansion. DISCUSSION: Repetitive stress and variations in intra-abdominal pressure can change tensile strength and stretches mesh materials...
September 30, 2016: International Journal of Surgery Case Reports
Q S Chen, X Ding, H M Wang
Objective: To investigate the effect of three types of material homogeneities(isotropy, transverse isotropy, and orthotropy) of mandible on the finite element analysis of implant. Methods: Three-dimensional model of complete mandible containing an implant was constructed and analyzed with isotropic, transversely isotropic, and orthotropic models, respectively. Results: The effective stress, tensile stress, and compressive stress of cortical bone of the orthogonal model were 1.2, 1.2, and 1.1 times larger than that of the isotropic model...
October 9, 2016: Zhonghua Kou Qiang Yi Xue za Zhi, Zhonghua Kouqiang Yixue Zazhi, Chinese Journal of Stomatology
Gian Piero Malfense Fierro, Michele Meo
Recently, there has been high interest in the capabilities of nonlinear ultrasound techniques for damage/defect detection as these techniques have been shown to be quite accurate in imaging some particular type of damage. This paper presents a Constructive Nonlinear Array (CNA) method, for the detection and imaging of material defects/damage in a complex composite stiffened panel. CNA requires the construction of an ultrasound array in a similar manner to standard phased arrays systems, which require multiple transmitting and receiving elements...
September 22, 2016: Ultrasonics
Brecht Van Hooreweder, Yanni Apers, Karel Lietaert, Jean-Pierre Kruth
: This paper provides new insights into the fatigue properties of porous metallic biomaterials produced by additive manufacturing. Cylindrical porous samples with diamond unit cells were produced from Ti6Al4V powder using Selective Laser Melting (SLM). After measuring all morphological and quasi-static properties, compression-compression fatigue tests were performed to determine fatigue strength and to identify important fatigue influencing factors. In a next step, post-SLM treatments were used to improve the fatigue life of these biomaterials by changing the microstructure and by reducing stress concentrators and surface roughness...
October 4, 2016: Acta Biomaterialia
Vahid Rahneshin, Farhad Khosravi, Dominika A Ziolkowska, Jacek B Jasinski, Balaji Panchapakesan
The ability to convert photons of different wavelengths directly into mechanical motion is of significant interest in many energy conversion and reconfigurable technologies. Here, using few layer 2H-MoS2 nanosheets, layer by layer process of nanocomposite fabrication, and strain engineering, we demonstrate a reversible and chromatic mechanical response in MoS2-nanocomposites between 405 nm to 808 nm with large stress release. The chromatic mechanical response originates from the d orbitals and is related to the strength of the direct exciton resonance A and B of the few layer 2H-MoS2 affecting optical absorption and subsequent mechanical response of the nanocomposite...
October 7, 2016: Scientific Reports
Jon O Wright, Nathan W Skelley, Reid P Schur, Ryan M Castile, Spencer P Lake, Robert H Brophy
BACKGROUND: The microstructural organization (collagen fiber alignment) of the posterior cruciate ligament (PCL), which likely corresponds with its functional properties, has only been described qualitatively in the literature, to our knowledge. The goal of this study was to quantify the tensile mechanical and microstructural properties of the PCL and compare these qualities between the anterolateral and posteromedial bundles. METHODS: Twenty-two knee specimens from 13 donors (8 male and 5 female; mean age [and standard deviation] at the time of death, 43...
October 5, 2016: Journal of Bone and Joint Surgery. American Volume
Eldho Abraham, Doron Kam, Yuval Nevo, Rikard Slattegard, Amit Rivkin, Shaul Lapidot, Oded Shoseyov
This work presents an environmentally friendly, iodine-catalysed chemical modification method to generate highly hydrophobic, optically active cellulose nanocrystals (CNC). The high degree of ester substitution (DS=2.18), hydrophobicity, crystalline behaviour and optical activity of the generated acetylated CNC (Ac-CNC) were quantified by TEM, FTIR, solid 13C NMR, contact angle, XRD and POM analyses. Ac-CNC possessing substantial enhancement in thermal stability (16.8%) and forms thin films with interlayer distance of 50-150 nm, presenting cavities suitable for entrapping nano and micro particles...
October 5, 2016: ACS Applied Materials & Interfaces
Guang Yao, Min Gao, Yanda Ji, Weizheng Liang, Lei Gao, Shengliang Zheng, You Wang, Bin Pang, Y B Chen, Huizhong Zeng, Handong Li, Zhiming Wang, Jingsong Liu, Chonglin Chen, Yuan Lin
Controllable interfacial strain can manipulate the physical properties of epitaxial films and help understand the physical nature of the correlation between the properties and the atomic microstructures. By using a proper design of vicinal single-crystal substrate, the interface strain in epitaxial thin films can be well controlled by adjusting the miscut angle via a surface-step-terrace matching growth mode. Here, we demonstrate that LaAlO3 (LAO) substrates with various miscut angles of 1.0°, 2.75°, and 5...
October 5, 2016: Scientific Reports
V Mazel, S Guerard, B Croquelois, J B Kopp, J Girardot, H Diarra, V Busignies, P Tchoreloff
Mechanical strength is an important critical quality attribute for tablets. It is classically measured, in the pharmaceutical field, using the diametral compression test. Nevertheless, due to small contact area between the tablet and the platens, some authors suggested that during the test, the failure could occur in tension away from the center which would invalidate the test and the calculation of the tensile strength. In this study, the flattened disc geometry was used as an alternative to avoid contact problems...
October 1, 2016: International Journal of Pharmaceutics
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