A novel hybrid approach for automated detection of retinal detachment using ultrasound images.

Retinal detachment (RD) is an ocular emergency, which needs quick intervention to preclude permanent vision loss. In general, ocular ultrasound is used by ophthalmologists to enhance their judgment in detecting RD in eyes with media opacities which precludes the retinal evaluation. However, the quality of ultrasound (US) images may be degraded due to the presence of noise, and other retinal conditions may cause membranous echoes. All these can influence the accuracy of diagnosis. Hence, to overcome the above, we are proposing an automated system to detect RD using texton, higher order spectral (HOS) cumulants and locality sensitive discriminant analysis (LSDA) techniques. Our developed method is able to classify the posterior vitreous detachment and RD using support vector machine classifier with highest accuracy of 99.13%. Our system is ready to be tested with more diverse ultrasound images and aid ophthalmologists to arrive at a more accurate diagnosis.

The hydrolytic degradation of polydioxanone (PDSII) sutures. Part I: Morphological aspects.

The morphological changes in polydioxanone sutures (PDSII), and the resulting changes in properties are explored as a function of in vitro degradation time with the use of small- and wide-angle x-ray scattering, optical microscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, and measurements of tensile properties and mass change. There are significant changes to the properties of the suture on initial hydration. In the time range of 0-80 days investigated, two subsequent stages of degradation are apparent. Chain scission is thought to occur in the first stage, beginning as soon as the chains become hydrated. However, in this stage, the effects of scission on the physical properties of the suture are not apparent. The transition from the first (dormant) stage to the second (active) stage, in which changes to the physical structure and mechanical properties of the fiber become measurable, is gradual, with the first change occurring after about 15 days. The relationships between the changes in the microstructure and the properties are discussed and a general model for the degradation process proposed.

The hydrolytic degradation of polydioxanone (PDSII) sutures. Part II: Micromechanisms of deformation.

An investigation of morphological changes in hydrolytically degraded polydioxanone sutures (PDSII) during in situ tensile deformation is reported. These changes were followed with the use of real-time small-angle X-ray scattering with simultaneous tensile deformation experiments. The results are correlated with separately performed wide-angle X-ray scattering, and optical microscopy experiments on the effects of tensile strain. Interlamellar and interfibrillar amorphous regions appear to control the microdeformation and the shape of the stress-strain curves of PDSII sutures. The fibers deform initially by interlamellar separation and at larger strains by fibrillar slip. Fractures appear to be caused by the catastrophic growth of cracks. The degradation of interlamellar tie chains in PDSII sutures does not appear to significantly affect the progress of deformation, because deformation through interlamellar separation is largely unchanged by degradation. Conversely, hydration and scission of interfibrillar tie chains lowers the load required to propagate interfibrillar shear. The fibers fail at progressively lower strains as degradation proceeds.