34 research outputs found
Die intracochleäre Elektrocochleographie beim Meerschweinchen - Entwicklung eines Diagnostikverfahrens für die humane CI-Implantation
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Papers in California Archaeology: 19-20
During April and May of 1949, test excavations were made at a largestratified shellmound on the shores of San Francisco Bay. 1 The site,designated in the records of the U.0. Archaeological Survey as 4-Mrn-115,is located on a point of land just north of San Rafael. The property isowned by Mr. W.H. Thomas of San Rafael, whose friendly cooperation in permittingthe excavation is here gratefully acknowledged.The preliminary excavations were made to check the stratigraphic andcultural associations of the mound. At the time, it was hoped that excavationof the site would be continued on a larger scale. However, variousfactors have prevented continuance of the work, and it now appears desirableto place on record the sketchy data obtained from the preliminary tests.The artifact sample is regrettably small, consisting of only a handful ofspecimens, but it appears sufficient to outline the cultural position of thesite. The excavation which has been done to date is of importance for tworeasons: first, a C14 date was obtained which throws some light on theterminal period of the Middle Horizon on San Francisco Bay, and second, aburned house ruin was exposed which merits description because of the rarityof such features in Central California archaeology
Optoacoustic effect is responsible for laser-induced cochlear responses
Optical stimulation of the cochlea with laser light has been suggested as an alternative to conventional treatment of sensorineural hearing loss with cochlear implants. The underlying mechanisms are controversially discussed: The stimulation can either be based on a direct excitation of neurons, or it is a result of an optoacoustic pressure wave acting on the basilar membrane. Animal studies comparing the intra-cochlear optical stimulation of hearing and deafened Guinea pigs have indicated that the stimulation requires intact hair cells. Therefore, optoacoustic stimulation seems to be the underlying mechanism. The present study investigates optoacoustic characteristics using pulsed laser stimulation for in vivo experiments on hearing Guinea pigs and pressure measurements in water. As a result, in vivo as well as pressure measurements showed corresponding signal shapes. The amplitude of the signal for both measurements depended on the absorption coefficient and on the maximum of the first time-derivative of laser pulse power (velocity of heat deposition). In conclusion, the pressure measurements directly demonstrated that laser light generates acoustic waves, with amplitudes suitable for stimulating the (partially) intact cochlea. These findings corroborate optoacoustic as the basic mechanism of optical intra-cochlear stimulation