The results suggest that superior semicircular canal dehiscence can affect hearing function by introducing a third window into the inner ear.

Measurements of umbo velocity and auditory brainstem response (ABR) were made on two different strains of mice, 129S6/SvEvTac (129S6) and CBA/ CaJ (CB), within three different age ranges. The velocity measurements were made with a laser Doppler vibrometer using a semiclosed sound delivery system; the frequency range of accurate velocity measurements is from 1 to 21 kHz. The visual detection threshold of the ABR was determined at selected frequencies between 2 and 32 kHz. The velocity results suggest a small but significant change in umbo velocity with age in both strains, between the youngest (1.5-3 months) and mid-aged (12-14 months) groups. There is also a clear difference in the umbo velocity in the youngest animals of the two strains, with the 129S6 having more sensitive middle-ear function than the CB. These results support the existence of a small age-related loss in middle-ear sensitivity in the mouse that was first described in the BALB/6J strain. The age-related changes in middleear function observed in both CB and 129S6 are much smaller than the age-related decreases in ABR. Our results also describe a statistically significant increase in the incidence of middle-ear pathology with age in the 129S6.

No abstract

Fibers that are termed "eco-friendly" or "biodegradable" by manufacturers are increasingly being used in textile products such as apparel and carpeting to appeal to the ever more environmentally aware public. As such, these modern fibers are expected to begin showing up more often in forensic casework, and it is important that the forensic examiner recognize them. This study employed polarized light microscopy (PLM) and Fourier transform infrared (FTIR) microspectroscopy to characterize selected fibers of azlon, polylactic acid (PLA), cellulose composites of alginate or chitin, and bamboo (viscose rayon). Fiber cross-sections, refractive indices, melting points, solubilities, and FTIR measurements were conducted. Results indicate that the azlons and PLA fibers are easily distinguishable from other textile fibers by their optical and chemical properties. The cellulose composites show only small differences in comparison with other cellulose-based fibers, while bamboo viscose rayon is indistinguishable from normal viscose rayon.

Manufactured fibers derived from natural origins include viscose rayon, azlon, and polylactic acid (PLA). A 2-year study was conducted to document any changes these fibers undergo as a result of exposure to various environmental conditions. Fabric swatches representing each fiber type were exposed to freshwater, saltwater, heat, cold, ultraviolet light, or composter conditions. Fibers from the swatches were periodically analyzed using polarized light microscopy and Fourier transform infrared microspectroscopy. Fiber solubility and melting-point behavior were measured every 6 months. Except for the complete degradation of viscose rayon in the composter, saltwater, and freshwater environs, no changes in the optical properties, infrared spectra, solubility, or melting points of the remaining fibers in any of the environments were observed. However, microscopic morphological changes were observed in fibers from two azlon swatches submerged in freshwater and saltwater, two PLA swatches exposed to ultraviolet light, and two viscose rayon swatches exposed to ultraviolet light.