scholarly journals Measurements of Young's Modulus of Elasticity of the Canine Aorta with Ultrasound

1979 ◽  
Vol 1 (4) ◽  
pp. 356-367 ◽  
Author(s):  
D.J. Hughes ◽  
C.F. Babbs ◽  
L.A. Geddes ◽  
J.D. Bourland
Keyword(s):  
Young’S Modulus ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Parietal Pleura ◽  
Young’S Modulus Of Elasticity ◽  
Blood Pressures ◽  
Canine Aorta

We have developed an ultrasonic technique for determining the dynamic Young's modulus of elasticity (E) of the canine aorta in vivo. Young's modulus was measured in the descending thoracic aorta (DTA) and the abdominal aorta (AA) of 12 dogs over a range of mean blood pressures from 40 – 200 mm Hg. The vessels were excised and dynamic moduli were determined in vitro post-mortem from pressure-volume curves. The data so obtained were compared to the in vivo values. In vivo and in vitro moduli increased exponentially with mean distending pressure (P). The equation of best fit for these data was of the form E = R0 exp(aP). E0 and a depend on the site of measurement (AA or DTA) and upon the particular animal. In vivo and in vitro moduli were not significantly different in the AA (AA: in vivo E0 = 667 ± 382 mm Hg, a = 0.017 ± 0.004 mm Hg-1 in vitro E0 = 888 ± 367, a = 0.016 ± 0.002). However, in vivo moduli exceeded in vitro moduli in the DTA. (DTA: in vivo E0 = 687 ± 241, a = 0.016 ± 0.004 in vitro E0 = 349 ± 64, a = 0.018 ± 0.003). The increased stiffness of the DTA compared to the AA in vivo may be due to the in situ tethering of the aorta to the spine by the parietal pleura.

scholarly journals In Vivo Noninvasive Measurement of Young’s Modulus of Elasticity in Human Eyes

2017 ◽  
Vol 26 (11) ◽  
pp. 967-973 ◽  
Author(s):  
Arthur J. Sit ◽  
Shuai-Chun Lin ◽  
Arash Kazemi ◽  
Jay W. McLaren ◽  
Christopher M. Pruet ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Noninvasive Measurement ◽  
Young’S Modulus Of Elasticity ◽  
Human Eyes

THE INFLUENCE OF SEX HORMONES ON THE BONY CHANGES OCCURRING IN PARALYSED LIMBS

1954 ◽  
Vol 11 (1) ◽  
pp. 66-70 ◽  
Author(s):  
J. A. GILLESPIE
Keyword(s):  
Young’S Modulus ◽  
Sex Hormones ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Bending Moment ◽  
Breaking Point ◽  
Total Weight ◽  
Breaking Stress ◽  
Young’S Modulus Of Elasticity ◽  
Ash Weight

SUMMARY 1. Paralysis, produced in young male rats by avulsion of peripheral nerves, resulted in a highly significant reduction in the total weight, ash weight, ash percentage, X-ray density and bending moment at the breaking point, of the bones of the affected limb. The breaking stress was significantly reduced, but Young's modulus of elasticity was unaltered. 2. Certain of these changes were modified by treatment with sex hormones. Both oestradiol and testosterone significantly reduced the difference between the bones of the normal and paralysed limbs in respect of total weight, ash weight and bending moment at the breaking point. 3. Treatment with oestradiol significantly increased both the ash percentage and Young's modulus of elasticity, the increase affecting equally the bones of the normal and paralysed limbs. Testosterone treatment did not significantly affect either of these properties, and neither hormone affected the breaking stress.

Mechanical Properties and Microarchitecture of Nanoporous Hydroxyapatite Bioceramic Nanoparticle Coatings on Ti and TiN

2006 ◽  
Vol 975 ◽  
Author(s):  
Andrei Stanishevsky ◽  
Shafiul Chowdhury ◽  
Nathaniel Greenstein ◽  
Helene Yockell-Lelievre ◽  
Jari Koskinen
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Biological Response ◽  
Dip Coating ◽  
Nano Crystalline ◽  
Ceramic Manufacturing ◽  
Nanoparticle Coatings

ABSTRACTThe hydroxyapatite (HA) based bioceramic materials are usually prepared at high sintering temperatures to attain suitable mechanical properties. The sintering process usually results in a material which is compositionally and morphologically different from nonstoichiometric nano-crystalline HA phase of hard tissue. At the same time, HA particulates used as precursors in ceramic manufacturing are often very similar to the natural HA nanocrystals. It has been shown that synthetic nanoparticle HA (nanoHA) based materials improve the biological response in vitro and in vivo, but the information on mechanical properties of these materials is scarce.In this work we studied the HA nanoparticle (10 – 80 nm mean size) coatings with 30 – 70% porosity prepared by a dip-coating technique on Ti and TiN substrates. It has been found that the mechanical properties of HA nanoparticle coatings are strongly influenced by the initial size, morphology, and surface treatment of nanoparticles. The nanoindentation Young's modulus and hardness of as–deposited nanoHA coatings were in the range of 2.5 – 6.9 GPa and 80 – 230 MPa, respectively. The coatings were stable after annealing up to at least 600 °C, reaching the Young's modulus up to 23 GPa and hardness up to 540 MPa, as well as in simulated body fluids.

Effects of Vertebral Body Changes on Cervical Spine Load Sharing

2002 ◽  
Author(s):  
Jiangyue Zhang ◽  
Narayan Yoganandan ◽  
Frank A. Pintar
Keyword(s):  
Cervical Spine ◽  
Young’S Modulus ◽  
Vertebral Body ◽  
Modulus Of Elasticity ◽  
Young's Modulus ◽  
Compressive Force ◽  
Axial Compressive Force ◽  
Inferior Surface ◽  
Biomechanical Behavior ◽  
Young’S Modulus Of Elasticity

The objective of the study was to determine the effects of changes in the Young’s modulus of elasticity of the cancellous bone that occur due to the ageing process on the biomechanical behavior of the cervical spine. An anatomically accurate three-dimensional (3-D) nonlinear finite element model of the C4-C5-C6 cervical spinal unit was used. The inferior surface of the C6 vertebrae was fixed in all degrees of freedom, and external loads were applied to the top surface of the C4 vertebra. The model was exercised under an axial compressive force of 754 N. In addition, flexion and extension bending moments of 3.44 Nm were applied individually to the model. The effects of ageing on bone strength were simulated by decreasing the Young’s modulus of elasticity from 100 MPa in the healthy spine to 40 MPa in the degenerated spine. The degenerated spine was found to be more flexible than the healthy spine. In addition, the degenerated spine responded with increased forces in the outer anterior and posterior regions of the vertebral body. Furthermore, forces in the facet joints increased in the degenerated spine. In contrast, the middle region of the disc showed decreased forces. These increases in the forces leading to stress risers may explain the occurrence of osteophytes in the spine with age.

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