The Raman spectrum of hematite (alpha-Fe2O3) is here discussed as a distinctive feature for Terra Sigillata sample wares. The broadening of the Raman lines and the appearance and increasing of the disorder band at 660 cm(-1), while moving from the external slip to the inner body, are proposed as valuation parameters for the study of the mineralogical composition and firing process of pottery productions.

SummaryPhotodegradation of bilirubin in vivo has been investigated by using green fluorescent sources according to the suggestions obtained in a previous study in vitro. Two groups of 50 jaundiced low-birth-weight infants were exposed to fluorescent light in phototherapy units under similar irradiant conditions. One group was exposed for 24 h to standard green tubes, the other, to daylight lamps. Newborns of the two groups were similar for gestational age, birthweight, and initial bilirubin concentration. A greater decrease in the serum concentration of bilirubin was found in subjects exposed to the green light when compared with infants exposed to daylight lamps.The use of green light is strongly suggested instead of the white, blue, and special blue lamps, because of the real efficiency, power and range of wave lengths.

The Kubelka–Munk theory of radiation transfer is applied to determine the influence of skin optical losses on the efficiency of phototherapy of jaundice. Using a multi‐layer model of the skin the photon absorption rate of bilirubin molecules is calculated for spectrally Gaussian light sources and fluorescent lamps used in phototherapy. Light absorption and scattering processes in the skin layers shift the optimum value of the peak excitation wavelength from λ= 453 nm (absorption maximum of bilirubin in vitro) to λ= 480 nm. This suggests the clinical investigation of narrow‐spectrum lamps emitting in the blue‐green region of the spectrum.

No abstract

No abstract