Experiments were conducted with a single, bilateral cochlear implant user to examine interaural level and time-delay cues that putatively underlie the design and efficacy of bilateral implant systems. The subject'...
详细信息
Experiments were conducted with a single, bilateral cochlear implant user to examine interaural level and time-delay cues that putatively underlie the design and efficacy of bilateral implant systems. The subject's two implants were of different types but custom equipment allowed presentation of controlled bilateral stimuli, particularly those with specified interaural time difference (ITD) and interaural level difference (ILD) cues. A lateralization task was used to measure the effect of these cues on the perceived location of the sensations elicited. For trains of fixed-amplitude, biphasic current pulses at 100 pps, the subject demonstrated sensitivity to an ITD of 300 μs, providing evidence of access to binaural information. The choice of bilateral electrode pair greatly influenced ITD sensitivity, suggesting that electrode pairings are likely to be an important consideration in the effort to provide binaural advantages. The selection of bilateral electrode pairs showing sensitivity to ITD was partially aided by comparisons of the pitch elicited by individual electrodes in each ear (when stimulated alone with fixed-amplitude current pulses at 813 pps): specifically, interaural electrodes with similar pitches were more likely (but not certain) to show ITD sensitivity. Significant changes in lateral position occurred with specific electrode pairs. With five bilateral electrode pairs of 14 tested, ITDs of 300 and 600 μs moved an auditory image significantly from right to left. With these same pairs, ILD changes of 11% of the dynamic range (in μApp) moved an auditory image from the far left to the far right - significantly farther than the nine pairs not showing significant ITD sensitivity. However, even these nine pairs did show response changes as a function of the interaural (or confounding monaural) level cue. Overall, insofar as the access to bilateral cues demonstrated herein generalizes to other subjects, it provides hope that the normal binaural advantages fo
A main limitation of biomedical devices is the inability to start, stop, and control cell growth making it crucial to develop biomaterial surfaces that induce a desired cellular response. Micropatterns of ridges and p...
详细信息
A main limitation of biomedical devices is the inability to start, stop, and control cell growth making it crucial to develop biomaterial surfaces that induce a desired cellular response. Micropatterns of ridges and pillars were created in a siloxane elastomer (Dow Corning) by casting against epoxy replicates of a micromachined silicon wafer. Silicone oils were incorporated to determine the change in modulus and surface energy caused by these additives. SEM and white light interference profilometry verified that the micropatterning process produced high fidelity, low defect micropatterns. Mechanical analysis is indicated that varying the viscosity, weight percent and functionality of the added silicon oil could change the elastic modulus by over an order of magnitude (0.1-2.3 MPa). As a self-wetting resin, silicone oils migrate to the surface, hence changing the surface properties from the bulk. Both topographical and chemical features define the surface energy, which in combination with elastic modulus, dictate biological activity. The results imply that the morphology, mechanical properties and surface energy of the siloxane elastomer can be modified to elicit a specific cell response as a function of engineered topographical and chemical functionalization.
Speech has been widely used for the diagnosis of the laryngeal function, and many methods have been developed in voice analysis. But, some methods cannot be applied in clinical case. So, we intend to present the new s...
详细信息
Speech has been widely used for the diagnosis of the laryngeal function, and many methods have been developed in voice analysis. But, some methods cannot be applied in clinical case. So, we intend to present the new schemes for the diagnosis of the voice using some parametric methods. We expect this scheme to be useful for the diagnosis of the patients' voices.
In vitro corrosion tests have not evaluated the role of cells on the corrosion of implant quality 316L stainless steel. A new cell-culture corrosion cell was used to simulate the clinical condition of cells attached t...
详细信息
In vitro corrosion tests have not evaluated the role of cells on the corrosion of implant quality 316L stainless steel. A new cell-culture corrosion cell was used to simulate the clinical condition of cells attached to and growing on the alloy to evaluate the effects of cells on alloy corrosion and the effect of corrosion products on cells. The corrosion potential, charge transfer, and surface composition of the alloy were measured in the presence and absence of macrophage cells (RAW 264.7) or cells stimulated to release NO over 72 hours. Whereas there was no statistical difference in the corrosion of 316L stainless steel in the presence of macrophage cells as compared to culture media alone, there was a trend for higher corrosion to occur in the presence of the cells. Corrosion was further reduced when cells were stimulated to release NO which may have oxidized the implant and contributed to an enhancement of its surface oxide. These data suggest that cells may alter alloy surface oxides and affect alloy corrosion.
Here we analyze two methods to analysis on the hand motor functional MRI of human. Statistical methods especially correlation method is considered as golden standard for assessing where is the region with some statist...
详细信息
Here we analyze two methods to analysis on the hand motor functional MRI of human. Statistical methods especially correlation method is considered as golden standard for assessing where is the region with some statistical confidence. But dependence on the fixed reference function can be source of error and inflexibility to estimate variable HRF(hemodynamic response function). So we implemented the ICA as a data-driven methods free from prior knowledge and constraints. We found that both of results are almost same in the sense of prior anatomical knowledge about activation site of motor function.
The use of several moral theories to analyze the legitimacy of engineering codes of conduct is discussed. Four different types of moral theories include, utilitarian theories, duty theories, rights theories and virtur...
详细信息
The use of several moral theories to analyze the legitimacy of engineering codes of conduct is discussed. Four different types of moral theories include, utilitarian theories, duty theories, rights theories and virture theories. engineering codes of conduct are not absolute standards which cannot be questioned. The weaknesses in these codes can be identified by appropriately using these different moral theories and the weaknesses should be modified.
Ideal Observer model predicts optimal observation conditions for human observer in detecting oral cavity neoplasia reflectance and fluorescence. We test these predictions in determining effectiveness of multi-spectral...
详细信息
We report on the first three dimensional tomographic localization of hemodynamic effects in the brain with diffuse optical tomography. Using a model-based iterative image reconstruction algorithms we localize spatial ...
详细信息
We performed three-dimensional optical tomographic brain imaging studies on small animals. Using near-infrared continuous light to probe rat brains, we were able to test our diffuse optical tomographic reconstruction ...
详细信息
暂无评论