Visualization of the photodegradation of a therapeutic drug by chemometric-assisted fluorescence spectroscopy.

The fluorescence spectral fingerprint, also known as the excitation-emission matrix (EEM), is used to assess and visualize therapeutic drug photodegradation in combination with chemometrics. Examination of EEM-parallel factor analysis (PARAFAC) data showed that an individual component was easily separated from a mixture of photogenerated products of a heterocyclic pharmacophore, in this case, phenothiazine drugs (PTZs). Detailed investigations of both structure-EEM relationships and kinetics revealed that the components extracted from EEM-PARAFAC could be quantitatively attributed to such photogenerated products as phenothiazine sulfoxide and carbazole derivatives. EEM in combination with principal component analysis (PCA) could be used as a mapping tool to visualize information of the photodegradation process of PTZs. We also assessed the photostability of various types of PTZs containing side chains by using validated EEM-PARAFAC methodology.

Bridged eosin Y: a visible and near-infrared photoredox catalyst.

Herein, a new NIR photoredox catalyst, bridged eosin Y (BEY), has been developed. Its detailed structure and NIR optical properties are clarified by using various spectroscopic methods, X-ray single-crystal structure analysis and DFT calculations. In addition, we demonstrate the photoreaction in colored reagents and high-concentration suspensions to show the advantage of NIR photoredox-catalyzed reactions.

[Diagnostic detection performance of a simulated nodule in chest computed tomography images and gray and color nuclear medicine images: comparison between a medical liquid crystal display monitor and an ordinary liquid crystal display monitor].

The purpose of this study was to evaluate the detection performance of simulated nodules in chest computed tomography (CT) images and nuclear medicine images with an ordinary liquid crystal display (LCD) and a medical LCD (grayscale standard display function: GSDF) and gamma 2.2. We collected 72 chest CT image slices obtained from an LSCT phantom with simulated signals composed of various sizes and CT values and 78 slices of monochrome and color nuclear medicine images obtained from a digital phantom with a simulated signal composed of various sizes and radiation levels. Six observers performed receiver operating characteristic (ROC) analysis using a continuous scale. The area under the ROC curve (AUC) was calculated for each monitor. The average AUC values for detection of chest CT images on a medical LCD (GSDF), medical LCD (gamma 2.2), and ordinary LCD were 0.71, 0.67, and 0.73, respectively. The average AUC values for detection of monochrome nuclear medicine images using a medical LCD (GSDF), medical LCD (gamma 2.2), and ordinary LCD were 0.81, 0.75, and 0.72, respectively. The average AUC values for detection of color nuclear medicine images on a medical LCD (GSDF), medical LCD (gamma 2.2), and ordinary LCD were 0.88, 0.86, and 0.90, respectively. Observer performance for detection of simulated nodules in chest CT images and nuclear medicine images was not significantly different between the three LCD monitors. We therefore conclude that an ordinary LCD monitor can be used to detect simulated nodules in chest CT images and nuclear medicine images.