The 1-alkoxy-4,5-dichloro-1,2,3-benzotriazole system

The 1-alkoxy-4,5-dichloro-1,2,3-benzotriazole system has been synthesized and characterized via its physical and chemical properties. INDO/S MO calculations provide a good account of the ultraviolet absorption spectrum.     

The photolysis of the l-cycloalkoxy-5-chloro-1,2,3-benzotriazole system

Three l-cycloalkoxy-5-chloro-1,2,3-benzotriazoles were photolyzed at 254 nm. The major photolytic pathway yielded the corresponding cyclic ketone and 4,4′-dichloroazobenzene.     

The 1-alkoxy-1,2,3-benzotriazole system

The 1-alkoxy-1,2,3-benzotriazole system has been synthesized and defined on the basis of its physical and spectral properties. Bond orders and charge densities of the parent compound in the series 1-methoxy-1,2,3-benzotriazole have been calculated. All-valence-electron calculations with configuration interaction give a reasonable account of the observed absorption spectrum.     

Field-based angle-resolved light-scattering study of single live cells

We perform field-based angle-resolved light-scattering measurements from single live cells. We use a laser interferometer to acquire phase and amplitude images of cells at the image plane. The angular scattering spectrum is calculated from the Fourier transform of the field transmitted through the cells. A concurrent 3D refractive index distribution of the same cells is measured using tomographic phase microscopy. By measuring transient increases in light scattering by single cells during exposure to acetic acid, we correlate the scattering properties of single cells with their refractive index distributions and show that results are in good agreement with a model based on the Born approximation.     

Confocal diffraction phase microscopy of live cells

We present a new quantitative phase microscopy technique, confocal diffraction phase microscopy, which provides quantitative phase measurements from localized sites on a sample with high sensitivity. The technique combines common-path interferometry with confocal microscopy in a transmission geometry. The capability of the technique for static imaging is demonstrated by imaging polystyrene microspheres and live HT29 cells, while dynamic imaging is demonstrated by quantifying the nanometer scale fluctuations of red blood cell membranes.