Near-infrared spectrometric determination of dipyrone in closed ampoules.

The present paper proposes an analytical method for fast near-infrared (NIR) determination of dipyrone in injectable formulations with a nominal content of 50.0%mv(-1) without violation of the ampoule. For this purpose, two multivariate calibration methods are evaluated, namely Partial-Least-Squares (PLS) and Multiple Linear Regression (MLR) with variable selection by the Successive Projections Algorithm (SPA). The resulting models comprised four latent variables (PLS) and five spectral variables (MLR-SPA). Appropriate predictions were obtained in both cases, with RMSEP values of 0.39 (PLS) and 0.35%mv(-1) (MLR-SPA) and correlation coefficients of 0.9970 (PLS) and 0.9975 (MLR-SPA) for a calibration range of 40-60%mv(-1). No systematic error was observed and no significant differences were found between the predicted and reference values, according to a paired t-test at 95% confidence level.

Adaptive wavelet EMG compression based on local optimization of filter banks.

This paper presents an adaptive wavelet technique for compression of surface electromyographic signals. The technique employs an optimization algorithm to adjust the wavelet filter bank in order to minimize the distortion of the compressed signal. Orthogonality of the transform is ensured by using a restriction-free parametrization described elsewhere. A case study involving real-life isotonic and isometric electromyographic signals is presented for illustration. The results show that the proposed approach outperforms the standard non-optimized wavelet technique in terms of the percent residual difference for a given compression factor.