Sodium Iodate Selectively Injuries the Posterior Pole of the Retina in a Dose-Dependent Manner: Morphological and Electrophysiological Study

Sequential morphological and functional features of retinal damage in mice exposed to different doses (40 vs. 20 mg/kg) of sodium iodate (NaIO3) were analyzed. Retinal morphology, apoptosis (TUNEL assay), and function (electroretinography; ERG) were examined at several time points after NaIO3 administration. The higher dose of NaIO3 caused progressive degeneration of the whole retinal area and total suppression of scotopic and photopic ERG. In contrast, the lower dose induced much less severe degeneration in peripheral part of retina along with a moderate decline of b- and a-wave amplitudes in ERG, corroborating the presence of regions within retina that retain their function. The peak of photoreceptor apoptosis was found on the 3rd day, but the lower dose induced more intense reaction within the central retina than in its peripheral region. In conclusion, these results indicate that peripheral area of the retina reveals better resistance to NaIO3 injury than its central part

Robust B-spline image modeling with application to image processing

In this correspondence, we present a new approach to two-dimensional (2-D) robust spline image smoothing based on the M-estimator algorithm. Unlike in other M-estimator based image processing algorithms, the new algorithm takes into consideration spatial relations between picture elements. The contribution of the sample to the model depends not only on the current residual of that sample, but also on the neighboring residuals. A smoothing parameter is estimated separately for each processing window and it adapts to the local structure of the image. The proposed algorithm is applied to image filtering. The resulting filter preserves details and suppresses additive Gaussian and impulsive noise efficiently. © 1998 IEEE

ECG data compression by spline approximation

A novel and efficient transform method for ECG data compression based on B-spline basis functions is proposed. The algorithm allows these basis functions to adapt their shape to the nonstationary behavior of ECG signals. The number and shape of these basis functions are completely characterized by the number and location of the so-called knots. The position of the knots can effectively be coded using run-length coding. Therefore, the overhead data required to describe the way the B-spline basis functions vary in time can be neglected compared to the gain in compression achieved by adaptation. The quasi-periodic nature of the ECG signal is used in order to further reduce redundant information in the data. Low bit-rates of the order of 160-200 bits/s are achieved with very good quality of the reconstructed signal. The algorithm is compared with other transform-based schemes (DCT and DLT), and was found superior at any bit-rate. (C) 1997 Elsevier Science B.V