this publication uses a colorimetric method based on the absorbance spectra of dye solutions to improve on beer’s law when calculating the dye concentrations of a three-component mixture. the performance of the new method is compared with that of beer’s law evaluated at three wavelengths, and beer’s law evaluated at 16 wavelengths. colorimetric method gives the best prediction of dye concentrat...

A type I absorbance change is observed in suspensions of adrenal cortical mitochondria as the temperature is increased from O-22”. This “heat-generated” type I absorbance change is similar in magnitude to the pregnenolone-induced type II absorbance change of these mitochondria. Studies with inhibitors of cholesterol side chain cleavage indicate that the heat-generated type I absorbance change r...

The predictions of the theory of light propagation in weakly absorbing anisotropic minerals are tested against systematic measurements of the infrared absorbance spectra of calcite, olivine, and topaz oriented in both principal and random sections, using both polarized and unpolarized light. We show that if the linear polarized maximum absorbance is smaller than ~0.3, or if the ratio of maximum...

Absorbance versus temperature curves can provide information on the thermal stability of DNA or RNA quadruplexes. Quadruplex denaturation or renaturation can be followed by recording absorbance at 295 nm rather than 260 nm, the wavelength used to monitor duplex denaturation. This unit describes the use of absorbance versus temperature curves to determine melting temperatures (T(m) values) and m...

The aim of the study was to explore the possibility of utilizing UV-absorbance measurements of spent dialysate to assess urea rebound. Ten patients on chronic three-times-a-week hemodialysis were included in the study. On-line UV-absorbance of spent dialysate was monitored. Urea rebound was calculated based on urea concentration in blood (Rb) and UV-absorbance in spent dialysate (Ra). Rb and Ra...

In this paper, a new method for recovering gas absorbance shape using wavelength modulation spectroscopy is proposed. We have mathematically proven that the gas absorbance shape can be directly recovered using the data of X and Y components of odd harmonics, regardless of the value of the modulation depth. The transitions of NH(3) near 1531 nm are selected to recover the absorbance shape using ...