The accurate measurement of the eye pressure is guaranteed only under the condition that the cornea stiffness is the same for all subjects. Conventional research evaluated the cornea stiffness by corneal displacement under an air puff. However, this displacement is not accurate enough because of the cornea deformation was treated in two dimension. In this paper, we capture the corneal deformation in three dimension under air puff and use the curvature to evaluate the cornea stiffness. Through experiments, we found an interesting tendency by statistical significance where the cornea stiffness is related to age.

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A control command input device using a Web camera for a functional electrical stimulation (FES) system has been developed. This input device is composed of a Web camera and a PC. An able-bodied subject's eye movements were detected from the Web camera employing an efficient image processing method, and some of these movements were converted into control commands for the FES system. We verified the performance of the system by conducting several experiments. The experimental results showed that the beginner able-bodied subjects could appropriately operate the input device and control the angles of their wrist joints.

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In the present study, we focused on the temporal information of the intrinsic optical signals in cat V2. The dynamic waveforms of the signals recorded in the visual cortical areas with different orientation selectivity were compared. The exposed visual cortical area was illuminated by the light with the wavelength of 605 ± 10 nm. Gratings were drifted at a velocity of 1.5 deg/s in the direction perpendicular to the grating orientations. The spatial frequency of the gratings was 0.5 cycles/deg. The orientations of the gratings were changed from horizontal (0 deg) to 157.5 deg with an interval of 22.5 deg. Each stimulus was presented 30 times. The response images were averaged over all the stimulus repetitions. Six hemispheres from three cats were used. In each of the optical patches with different orientation selectivity, time course of the intrinsic optical signal was examined, and the peak delay denoting as the time period from the stimulus onset to the time at which the intrinsic optical signal reached its maximum was measured. The delays responded to the stimuli of 0 deg and 90 deg gratings were 1.96 ± 0.26 s and 2.09 ± 0.38 s (mean ± SE, n = 6) in the cortical areas preferred to the orientations of 0 deg and 90 deg, respectively. In contrast, the delays responded to 45 deg and 135 deg gratings were 2.30 ± 0.21 s, and 2.21 ± 0.24 s in the cortical areas selectively responding to the gratings of 45 deg, and 135 deg orientations, respectively. The peak delays in the area with the preference of oblique orientations were statistically significant longer than those with the preference of cardinal orientations. The results may suggest a neuronal basis for the difference in the cognitive information processing between the oblique and the cardinal orientations.

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The purpose of this study is to investigate the nonlinearity in digital X-ray images as a feasibility study for a noise reduction process using a mathematical model, which realizes an accurate digital X-ray image system. To develop this mathematical model, it is important to confirm whether the system is linear or nonlinear. We have verified the nonlinearity of the digital X-ray image system through analysis of computed radiography (CR) images by using the method of surrogate, a type of statistical test of nonlinearity, applied the Wayland test. In the method of surrogate, we use the Fourier transform surrogate method. The Wayland test can be used for evaluating the complexity of the orbit of a signal aggregate called the attractor reconstructed in a high-dimensional phase space, setting the delay difference on the coordinate axes from the original data using a nonlinear statistical parameter called the translation error. The nonlinearity is determined by statistically comparing the translation error of the original data with that of the surrogate data. X-ray images are obtained under different conditions to investigate the effects of various tube voltages-50 and 80kV-and dose settings-2 and 10 mAs. We extract 30 line profiles from both directions of the X-ray images as original data. One is the direction vertical to the X-ray tube (X-direction), and the other is the direction horizontal to the X-ray tube (Y-direction). In the Y-direction, nonlinearity is found at all voltage and dose settings. On the other hands, nonlinearity is only found at 10 mAs and 80 kV in the X-direction. On the basis of this result, the nonlinearity is indicated by decrease in fluctuation of the X-ray photon. Therefore, the factors of nonlinearity exhibit a comprehensive variation of pixel values produced by the digital X-ray image system contained the X-ray imaging.

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The aim of this study was to clarify the mechanical action of the infant tongue during sucking. Therefore we developed an artificial nipple that contained multiple small built-in force sensors which was capable of measuring tongue-artificial nipple contact pressure in real-time. A force sensor was a cantilever structure composed of a thin stainless steel beam and all-purpose foil strain gauges attached to the surface of the beam. The signals obtained from the force sensor were amplified, and were transferred to a PC via a USB port. Using this system, measurements were taken in three infants. The output waveform was observed in all subjects, and the rate of sucking was about two times per second. In addition, the pressure waveform indicated peristalsis-like movement of tongue in infants with established oral feeding. This system can quantitatively measure individual differences in tongue movement.

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Decellularized tissues and organs have been intensively studied in order to use them as a scaffold for proliferation of recipient cells in tissue engineering/regenerative medicine applications. We established a fast and effective method for tissue decellularization by way of shaking a tissue in a detergent at 300 rpm. In addition, we developed a ring-clamp for fixation of decellularized tissue and created a scaffold module for cell culture by the combination of the ring-clamp and decellularized tissue. The module can be placed in a well of a commercially available 24-well plate. Smooth muscle cells that were seeded on a scaffold module consisting of a decellularized vessel and the ring-clamp showed proliferation with a spindle shape similar to that of vascular smooth muscle cells in the biological body. Vascular endothelial cells that adhered to the scaffold module showed enhanced susceptibility to histamine-induced Ca²⁺ influx.

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In an oddball paradigm in auditory MEG and EEG measurements, an averaged response to frequently presented standard auditory stimulus and that to infrequently presented deviant stimulus are compared to study various aspects of automatic processing of auditory information in the brain. This paper discusses methods for presenting the difference between the responses to standard and deviant stimuli obtained by multi-channel recording. Specifically, we compared R(Δ), the RMS (across the MEG or EEG channels) of the difference between the standard and deviant responses and Δ(R), the difference between the RMS of the standard and that of the deviant response. To evaluate the behaviors of R(Δ) and Δ(R). we used a very simple signal model and obtained the averages and variances of these two statistics in two typical situations. The first is where a mismatch response is elicited and in the other, the responses are equal. Based on this analysis, A(R, Δ), the average of R(Δ) and Δ(R) was recommended. The statistical behavior of A(R, Δ) was also discussed.

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