991 resultados para corrosion product
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This paper studies the test-retest reliability of distortion product otoacoustic emissions (DPOAE) in newborns in a neonatal intensive care unit.
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This paper describes a project which set up a system to measure distortion product otoacoustic emissions (DPOAEs) in the Sprague Dawley rat and to conduct a pilot study to measure the development of DPOAEs as a function of age.
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This paper discusses a study done of neonates to determine the differences between ABR and DPOE for hearing screening.
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This paper discusses the effect of noise exposure on high school aged boys' hearing levels and how to measure the effects.
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This paper studies the relationship between hearing sensitivity and the presence of otoacoustic emissions by examining the variability of same ear emissions in a group of normal-hearing subjects.
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This paper examines distortion product otoacoustic emissions (DPOAEs) used to test peripheral auditory function, and how noise level in the ear affects the detectability of DPOAEs. The study examines the clinical feasibility of different time averages at different frequencies on the noise floor.
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This paper is a review of a study on distortion product emissions in normal hearing chinchillas.
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This paper discusses the distortion-product otoacoustic emissions (DPOAE) of chinchillas when exposed to noise.
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Recovery of distortion product otoacoustic emissions in the bullfrog after noise exposure does not correlate with hair cell damage noted on the amphibian papilla.
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Terpene synthases are responsible for the biosynthesis of the complex chemical defense arsenal of plants and microorganisms. How do these enzymes, which all appear to share a common terpene synthase fold, specify the many different products made almost entirely from one of only three substrates? Elucidation of the structure of 1,8-cineole synthase from Salvia fruticosa (Sf-CinS1) combined with analysis of functional and phylogenetic relationships of enzymes within Salvia species identified active-site residues responsible for product specificity. Thus, Sf-CinS1 was successfully converted to a sabinene synthase with a minimum number of rationally predicted substitutions, while identification of the Asn side chain essential for water activation introduced 1,8-cineole and alpha-terpineol activity to Salvia pomifera sabinene synthase. A major contribution to product specificity in Sf-CinS1 appears to come from a local deformation within one of the helices forming the active site. This deformation is observed in all other mono- or sesquiterpene structures available, pointing to a conserved mechanism. Moreover, a single amino acid substitution enlarged the active-site cavity enough to accommodate the larger farnesyl pyrophosphate substrate and led to the efficient synthesis of sesquiterpenes, while alternate single substitutions of this critical amino acid yielded five additional terpene synthases.