Purpose To analyze the age dependence of the longitudinal modulus of the crystalline lens in vivo using Brillouin scattering data in healthy subjects. Methods Brillouin scans were performed along the crystalline lens in 56 eyes from 30 healthy subjects aged from 19 to 63 years. Longitudinal elastic modulus was acquired along the sagittal axis of the lens with a transverse and axial resolution...

We measure the viscoelasticity of entangled F-actin over length scales between 1 and 100 microm using one- and two-particle microrheology, and directly identify two distinct microscopic contributions to the elasticity. Filament entanglements lead to a frequency-independent elastic modulus over an extended frequency range of 0.01-30 rad/sec; this is probed with one-particle microrheology. Longit...

although carbon nanotubes (cnt) have been employed as reinforcements in nanocomposites, presence of nano scale defects such as stone-wales and vacancy defects in carbon nanotubes (cnt) weakens the mechanical properties of these materials. in this paper the effects of defects in cnts on nanocomposite elastic behavior are investigated using molecular dynamics. stiffness matrices of cnt and nanoco...

One of the parameters that has been identified as influencing the structural response of buildings is the dynamic Modulus of Elasticity of masonry units. The first aim of this paper is to experimentally investigate the use of high frequency sinusoidal loading to determine the dynamic Modulus of Elasticity of masonry units. The Longitudinal Vibration and the Ultrasonic Pulse methods were origina...

The biophysical and biomechanical properties of the crystalline lens (e.g., viscoelasticity) have long been implicated in accommodation and vision problems, such as presbyopia and cataracts. However, it has been difficult to measure such parameters noninvasively. Here, we used in vivo Brillouin optical microscopy to characterize material acoustic properties at GHz frequency and measure the long...

Metallic nickel nanowires with excellent physical properties have been introduced into polydimethylsiloxane (PDMS) matrix to form polymer nanocomposites. Nanowires were synthesized by template-assisted electrochemical deposition. By utilizing ferromagnetic nickel nanowires, small external magnetic field can be used to control their alignment and distribution during composite synthesis. Unlike d...

The elastic constants of tetrahedral amorphous carbon ~ta-C! and hydrogenated tetrahedral amorphous carbon ~ta-C:H! thin films were determined nondestructively by surface Brillouin scattering. Besides the usual Rayleigh surface mode, we also observe a new pseudosurface acoustic mode of longitudinal polarization, which is a modified version of the longitudinal guided mode usually found in slow-o...

To enhance preventative and therapeutic strategies for metabolic bone diseases and bone fragility disorders, we began to explore the physical properties of bone tissue at the cellular level. Proximal femurs were harvested from 27 cadavera (16 male and 11 female) for in vitro measurement of the mechanical properties. We measured the variations in lamellar-level elastic modulus and hardness in hu...

Molecular dynamics simulations together with micromechanics method have been proven an effective approach to assess the elastic moduli of either partially or fully exfoliated (i.e. single-layer) effective clay (montmorillonite) cluster. In this work, similar approach was adopted to estimate the overall compressive modulus of nylon 6/montmorillonite nanocomposites. In detail, the compressive mod...

little is known about the interaction of tissue conditioners and modeling plastics. this study evaluates the influence of a variety of commercial tissue conditioners on alteration of viscoelastic properties of modeling plastics.in this in vitro study, the dynamic viscoelastic properties of four commercially available tissue conditioners (tc), visco-gel (vg), gc soft-liner (sl), fitt (ft), and c...