No abstract

Hepatitis C has become one of the higher health problems around the world. Near-infrared Raman spectroscopy had been used to spectrally differentiate among health human blood serum from the one with hepatitis C contaminationin vitro. In this study a Raman spectrometer with 80 mW, 830 nm excitation, liquid-nitrogen cooled CCD and imaging spectrograph were used to collect Raman scattering from 24 blood samples (14 healthy and 10 diseased) with collection time of 120 s. It has been used an algorithm based on the Principal Components Analysis (PCA) for main spectral features identification and Mahalanobis distance for blood spectrum classification depending on the serology. It was observed that the highest spectral differences between the two types of human blood serum were found in 1002, 1169, 1262 and 1348 cm−1Raman bands. The spectral analysis using multivariate statistics presented good results when compared to classical diagnosis for viral hepatitis C, showing that Raman spectroscopy can classify human blood serum spectrum in one of the two categories by identifying biochemical alterations that occur in the presence of viral infections.

The kinetics aspects of the photoinitiated polymerization of tetrahydrofuran with triphenylsulfonium hexafluoroarsenate and sensitized by phenothiazine was studied under visible‐light irradiation. A photosensitizer mechanism was proposed involving electron transfer from phenothiazine to the triphenylsulfonium salt, forming a cation radical, the true precursor of the polymerization. An initial complex in the ground state between the phenothiazine and the triphenylsulfonium was formed prior to the excitation, and this complex actually activated the photopolymerization rate. The polymerization conversion presented an S‐shaped curve, suggesting an induction period caused by the existence of two pathways responsible for the beginning of the polymerization. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 46–55, 2001