A self-reset pixel of 15 × 15 µm2 with high signal-to-noise ratio (effective peak SNR ≃64 dB) for an implantable image sensor has been developed for intrinsic signal detection arising from hemodynamic responses in a living mouse brain. For detecting local conversion between oxyhemoglobin (HbO) and deoxyhemoglobin (HbR) in brain tissues, an implantable imaging device was fabricated with our newly designed self-reset image sensor and orange light-emitting diodes (LEDs; λ = 605 nm). We demonstrated imaging of hemodynamic responses in the sensory cortical area accompanied by forelimb stimulation of a living mouse. The implantable imaging device for intrinsic signal detection is expected to be a powerful tool to measure brain activities in living animals used in behavioral analysis.
To decrease the circuit priming volume, develop safety, and simplify the equipment, a cardiopulmonary bypass (CPB) circuit using a vacuum suction venous drainage system with a pressure relief valve was developed. The efficacy of this vacuum system was compared to that of a conventional siphon system. The system contains a powerful vacuum generator and a pressure relief valve to keep the negative pressure constant when blood suction is used. Using 8 mongrel dogs, the feasibility and the efficacy of this CPB system was tested. The changes in the negative pressure in the reservoir were within 5 mm Hg whether the suction lines were switched on or off. In all animals the amount of blood in the venous reservoir was stable throughout bypass. The decrease of priming volume was from 725 ml (siphon system) to 250 ml (vacuum system). At the end of CPB, the levels of hemoglobin in the vacuum system were significantly higher than those in the siphon system. These results demonstrated that this vacuum drainage system can provide simplification and a miniaturization of the cardiopulmonary bypass circuit resulting in low hemodilution during CPB.
Abstract— When moving images are displayed on matrix displays which reproduce gray levels utilizing pulse‐number/width‐modulation techniques, degradation of the gray levels and colors are often observed. The degradation originates from a temporal non‐uniformity of the light‐emission pattern, which is transformed into a spatial non‐uniformity of the light emission due to an after‐image effect of the eyes, which follow the image motion. The degradation becomes appreciable when the product of the speed of the viewing point on a screen and the light‐emission period of a pixel is greater than the pixel pitch. The degree of degradation is also affected by the pixel arrangement; disturbances for the stripe arrangement are worse than those for the triangle arrangement. The temporal uniformity is degraded when the major light‐emitting blocks of the pulse‐number/width‐modulation change. The uniformity can be improved by dividing the blocks of the major bits. It was analytically verified that the perceived luminance of periodic light emission is proportional to the emission duty factor (which coincides with Talbot‐Plateau's law) and also to the integral of f(t)dt from zero to infinity, independent of decay shape, f(t), of the after‐image.
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