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tensile stress

Abhishek S Mahajan, Young Gun Kim, Jae Hwa Kim, Prashanth D'sa, Azhar Lakhani, Hyun Soo Ok
BACKGROUND: To assess the functional and radiological outcomes of minimally invasive anterior bridge plating (ABP) for mid-shaft humerus fractures in patients predominantly involved in overhead activities (athletes and manual laborers). METHODS: Forty-eight patients fulfilling inclusion criteria were treated with ABP at a level-I trauma center using a 4.5-mm dynamic/locking compression plate and followed for a period of 1 year. Functional outcome was assessed using the Constant, Mayo elbow, and Disabilities of the Arm, Shoulder and Hand (DASH) scores...
December 2016: Clinics in Orthopedic Surgery
Seung-Yeol Jeon, Jinhyeok Jang, Bon-Woong Koo, Young-Woon Kim, Woong-Ryeol Yu
Due to the outstanding mechanical properties of individual carbon nanotubes (CNTs) at the nanoscale, CNT yarns are expected to demonstrate high strength at the macroscale. In this study, a predictable model was developed to predict the tensile strength of twisted CNT yarns. First, the failure mechanism of twisted CNT yarns was investigated using in situ tensile tests and ex situ observations. It was revealed that CNT bundles, which are groups of CNTs that are tightly bound together, formed during tensile loading, leaving some voids around the bundles...
November 29, 2016: Nanotechnology
D G Kvashnin, M Ghorbani-Asl, D V Shtansky, D Golberg, A V Krasheninnikov, P B Sorokin
Record high values of Young's modulus and tensile strength of graphene and BN nanoribbons as well as their chemically active edges make them promising candidates for serving as fillers in metal-based composite materials. Herein, using ab initio and analytical potential calculations we carry out a systematic study of the mechanical properties of nanocomposites constructed by reinforcing an Al matrix with BN and graphene nanoribbons. We consider a simple case of uniform distribution of nanoribbons in an Al matrix under the assumption that such configuration will lead to the maximum enhancement of mechanical characteristics...
November 28, 2016: Nanoscale
R G Shah, M C Pierce, F H Silver
BACKGROUND: Collagenous tissues store, transmit and dissipate elastic energy during mechanical deformation. In skin, mechanical energy is stored during loading and then is dissipated, which protects skin from mechanical failure. Thus, energy storage (elastic properties) and dissipation (viscous properties) are important characteristics of extracellular matrices (ECMs) that support the cyclic loading of ECMs without tissue failure. METHODS: Uniaxial stress-strain measurements on decellularized human dermis have been made and compared to results of a non-destructive technique involving optical coherence tomography (OCT) combined with vibrational analysis...
November 27, 2016: Skin Research and Technology
A Nawaz, W G Mao, C Lu, Y G Shen
The nanoscale elastic-plastic response of single crystal 4H-SiC has been investigated by nanoindentationwith a Berkovich tip. The hardness (H) and elastic modulus (E) determined in the load-independent region were 36±2GPa and 413±8GPa, respectively. The indentation size effect (ISE) of hardness within an indentation depth of 60nm was systematically analyzed by the Nix-Gao model. Pop-in events occurring at a depth of ~23nm with indentation loads of 0.60-0.65mN were confirmed to indicate the elastic-plastic transition of the crystal, on the basis of the Hertzian contact theory and Johnson's cavity model...
November 17, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Jennifer Chung, Kevin Lachapelle, Raymond Cartier, Rosaire Mongrain, Richard L Leask
Biomechanical characterization of the aortic wall may help risk stratify patients with aneurysms. We investigated the degree of anisotropy, the directional dependency of mechanical properties, in control and aneurysmal ascending aortic tissue. We hypothesized that medial degeneration and aortic wall remodeling as found in aneurysmal tissue alter energy loss in both the circumferential and longitudinal directions, thereby reducing anisotropy. Aneurysmal and control ascending aortic tissue excised during surgery was subjected to biaxial tensile testing...
November 15, 2016: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
Ron N Alkaly, Dan L Bader
STUDY DESIGN: A biomechanical study using bovine thoracolumbar spines. OBJECTIVE: To study investigated whether thread design parameters aimed at altering the state of stress at the screw-bone interface increase the screw's holding power. SUMMARY AND BACKGROUND DATA: Internal spinal fixators utilizing transpedicular screw fixation are used to achieve early stabilization of the injured spine in a range of clinical conditions. Despite advances in the design of internal spinal fixation systems, implant loosening, and catastrophic failures at the screw-bone interface remains a serious complication in adult spine surgery...
December 2016: Clinical Spine Surgery
Jinxing Zhao, Cui Liu, Yunchuan Li, Jiyuan Liang, Jiyan Liu, Tonghui Qian, Jianjun Ding, Yuan-Cheng Cao
Urethane acrylate (UA) was used to prepare carbon quantum dots (C-dots) luminescent membranes and the resultants were examined with FT-IR, mechanical strength, scanning electron microscope (SEM) and quantum yields (QYs). FT-IR results showed the polyurethane acrylate (PUA) prepolymer -C = C-vibration at 1101 cm(-1) disappeared but there was strong vibration at1687cm(-1) which was contributed from the-C = O groups in cross-linking PUA. Mechanical strength results showed that the different quantity of C-dots loadings and UV-curing time affect the strength...
November 21, 2016: Luminescence: the Journal of Biological and Chemical Luminescence
Michael D Newton, Abigail A Davidson, Ryan Pomajzl, Joseph Seta, Michael D Kurdziel, Tristan Maerz
Rotator cuff tears are a common shoulder pathology. The rat supraspinatus tendon model is commonly employed for preclinical assessment of rotator cuff pathology or regeneration. However, there is a lack of a standardized biomechanical testing protocol; previous studies have tested the tendon at abduction angles ranging from -15° to 90°. This study aimed to assess the effect of abduction/testing angle on the biomechanical properties of the rat supraspinatus tendon. Fourty-eight shoulders (n=12/group) from healthy Sprague-Dawley rats were randomized to 4 testing angle groups: 0° (corresponding to 90° abduction), 30°, 60°, and 90° (0° abduction)...
November 9, 2016: Journal of Biomechanics
Robert Oven
Electrically poled layers have been formed in soda-lime glass using graphite electrodes in air. The refractive index and thickness of the poled glass layers have been measured by the analysis of leaky optical modes. These modes are supported by the poled layer and can be determined by analysis of the optical reflectivity measured with a prism coupler arrangement. A relatively constant refractive index of ∼1.486 in the poled glass region is measured, which is ∼0.03 below the substrate index. The reflectivity data shows that the transition between poled and unpoled glass is very sharp and is consistent with ion transport models...
November 10, 2016: Applied Optics
Long Li, Wenyan Zhang, Jizeng Wang
Cells can adapt their mechanical properties through cytoskeleton remodelling in response to external stimuli when the cells adhere to the extracellular matrix (ECM). Many studies have investigated the effects of cell and ECM elasticity on cell adhesion. However, experiments determined that cells are viscoelastic and exhibiting stress relaxation, and the mechanism behind the effect of cellular viscoelasticity on the cell adhesion behaviour remains unclear. Therefore, we propose a theoretical model of a cluster of ligand-receptor bonds between two dissimilar viscoelastic media subjected to an applied tensile load...
October 2016: Royal Society Open Science
Qiang Liu, Xiaoqing Hu, Xin Zhang, Xiaoning Duan, Peng Yang, Fengyuan Zhao, Yingfang Ao
Mechanical factors play a key role in regulating the development of cartilage degradation in osteoarthritis. This study aimed to identify the influence of mechanical stress in cartilage and chondrocytes. To explore the effects of mechanical stress on cartilage morphology, we observed cartilages in different regions by histological and microscopic examination. Nanoindentation was performed to assess cartilage biomechanics. To investigate the effects of mechanical stress on chondrocytes, cyclic tensile strain (CTS, 0...
November 17, 2016: Scientific Reports
Wei Boon Yap, Faisal Malau Ahmad, Yi Cheng Lim, Satirah Zainalabidin
Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8)...
November 2016: Korean Journal of Physiology & Pharmacology
Ali Tavassolizadeh, Karsten Rott, Tobias Meier, Eckhard Quandt, Hendrik Hölscher, Günter Reiss, Dirk Meyners
Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner-Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity...
November 11, 2016: Sensors
Parthiban Anbalagan, Srimanta Sarkar, Celine V Liew, Paul W S Heng
This study aims to investigate the influence of tablet punch head design on compaction and the resultant tablet mechanical properties. Tablets were prepared using flat-face punches with different head flat and head radius configurations, on a rotary tablet press with compression rolls of different diameters. The results showed that tablets produced using punches with head flats consistently displayed higher tensile strengths and lower capping tendencies. Exclusion of the head flat in the punch head geometry caused the compacts to undergo a state of continual deformation during the compaction cycle, possibly with increasing elasticity without the opportunity for more prolonged stress relaxation...
November 11, 2016: Journal of Pharmaceutical Sciences
Viet Q Bui, Hung M Le, Yoshiyuki Kawazoe, Yongho Kim
In this paper, we propose the use of benzene (Bz) to cover the active site on top of a transition metal atom (Cr/Mn/Fe) adsorbed on the MoS2 monolayer. Stable configurations of adatom on the MoS2 surface were predicted using first-principles calculations and their electronic, magnetic properties were investigated. In addition, the influence of vertical electric field on the electronic band structures of the systems was carefully examined. Analyzing the adsorption energies of transition metals given by the PBE calculations, we found that the benzene molecule stabilized the binding of Cr and Mn on the MoS2 surface, but destabilized the Fe binding by approximately 33% of adsorption energy...
November 10, 2016: Journal of Physics. Condensed Matter: An Institute of Physics Journal
D Nagarajan, Balashanmugam Baskaranarayanan, K Usha, M S Jayanthi, M Vijjaykanth
INTRODUCTION: The application of light and continuous forces for optimum physiological response and the least damage to the tooth supporting structures should be the primary aim of an orthodontist. Nickel-titanium (NiTi) alloys with their desirable properties are one of the natural choices of the clinicians. AIM: This study was aimed to compare and rank them based on its tensile strength and electrical resistivity. MATERIALS AND METHODS: The sample consisted of eight groups of 0...
October 2016: Journal of Pharmacy & Bioallied Sciences
Laura C Mozdzen, Alan Vucetic, Brendan A C Harley
The tendon-to-bone junction is a highly specialized tissue which dissipates stress concentrations between mechanically dissimilar tendon and bone. Upon injury, the local heterogeneities across this insertion are not regenerated, leading to poor functional outcomes such as formation of scar tissue at the insertion and re-failure rates exceeding 90%. Although current tissue engineering methods are moving towards the development of spatially-graded biomaterials to begin to address these injuries, significant opportunities remain to engineer the often complex local mechanical behavior of such biomaterials to enhance their bioactivity...
October 27, 2016: Journal of the Mechanical Behavior of Biomedical Materials
Maki Hiraoka, Kunihiko Nakamura, Hidekazu Arase, Katsuhiko Asai, Yuriko Kaneko, Stephen W John, Kenji Tagashira, Atsushi Omote
A fibre actuator that generates a large strain with high specific power represents a promising strategy to develop novel wearable devices and robotics. We propose a new coiled-fibre actuator based on highly drawn, hard linear low-density polyethylene (LLDPE) fibres. Driven by resistance heating, the actuator can be operated at temperatures as low as 60 °C and uses only 20% of the power consumed by previously coiled fibre actuators when generating 20 MPa of stress at 10% strain. In this temperature range, 1600 W kg(-1) of specific work (8 times that of a skeletal muscle) at 69 MPa of tensile stress (230 times that of a skeletal muscle) with a work efficiency of 2% is achieved...
November 4, 2016: Scientific Reports
Kavitha Kadirvelu, Nishter Nishad Fathima
Drawing inspiration from the field of designer self-assembling materials, this work is aimed to focus on the self-assembling nature of extracted peptides. Hair keratin, a proteinacious reject in tanning industry has been chosen since they have been extracted and used for wide range of applications. Keratin source was subjected to five hydrolysis treatments (viz., sulphitolysis, β-mercaptoethanol, ionic liquid, thioglycolic acid and alkali) and assayed for functional groups. This was followed by the prediction of secondary structure using circular dichroism, determining the microstructural level to which the extracted peptide has self-assembled...
November 4, 2016: Scientific Reports
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