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The ocular lens stiffens dramatically with age, resulting in a loss of function. However, the mechanism of stiffening remains unknown, at least in part due to difficulties in making reliable measurements of the intrinsic mechanical properties of the lens. Recent experiments have employed manual compression testing to evaluate the stiffness of murine lenses which have genotypes pertinent to human lens diseases. These experiments compare the extrinsic stiffness of lenses from the genotype of interest to the wild-type lens in an effort to reach conclusions regarding the cellular or molecular basis of lens stiffening. However, these comparisons are confounded by alterations in lens size and geometry which invariably accompany these genetic manipulations. Here, we utilize manual lens compression to characterize the stiffness of a porcine lens and a murine lens. An inverse elastographic technique was then developed to estimate the intrinsic shear modulus of each lens as well as the elastic modulus of the lens capsule. The results were in good agreement with the previous literature values. [ABSTRACT FROM AUTHOR]

Solidification and growth behavior of undercooled eutectic CoSi–CoSi 2 melts was observed using containerless levitation and in situ high-energy synchrotron X-ray diffraction techniques. Three metastable solidification pathways of eutectic CoSi–CoSi 2 were determined as a function of undercooling. Upon double recalescence at low undercoolings the primary and secondary phases are CoSi and CoSi 2 , while at high undercoolings the phase formation sequence is reversed. At intermediate undercoolings a single recalescence was observed and attributed to a crossover of the nucleation barriers for the two phases. Scanning electron microscopy combined with electron back-scattering diffraction measurements revealed changes of the morphological characteristics and orientation of CoSi and CoSi 2 phases for different solidification pathways. Image 1 [ABSTRACT FROM AUTHOR]