1. The authors fail to distinguish adequately between photodegradation, in which bilirubin is degraded to substances of lower molecular weight, and photoisomerization, in which the pigment’s structure changes but no degradation occurs. Both processes contribute to the effects of phototherapy in humans, but their relative contributions are presently unknown. However, in the Gun rat animal model ...

The rate of volatilization of dinoseb may depend on soil acidity, temperature, surface soil moisture, the method of application, and the type of formulation (Kaufman 1976). Cohen et al. (1984) reported a volatilization half-life of 26 d. The significance of volatilization has been evidenced by the killing of plants by dinoseb vapours (Davis et al. 1954). Photodegradation is a major fate process...

To probe the mechanisms responsible for pH and dissolved oxygen (DO) affecting the photodegradation of 17α-ethynylestradiol (EE2) in dissolved humic acid (HA) solution, EE2 aqueous solutions with pH values ranging from 3.0 to 11.0 and different DO conditions were irradiated by using a 300 W mercury lamp equipped with 290 nm light cutoff filters. In 5.0 mg L(-1) HA solutions (pH 8.0), EE2 was de...

17α-Ethynylestradiol (EE2) has gotten growing concerns due to its widely detected in the environment and high estrogenic potency. However, the knowledge on the photochemical behaviors of EE2 in natural waters is still limited. Herein, the photodegradation and estrogenic potency variation of EE2 induced nitrate were studied using a sunlight simulator consisted by a 300 W medium pressure mercury ...

A method is described for obtaining the rate constant of the photodegradation process of fluorophores illuminated by a focused laser beam. The explicit kinetic equations, describing the population dynamics of excited singlet and triplet states, are averaged over the illuminated volume to describe the resulting fluorescence signal. The illumination is modulated at frequencies from 1 Hz to 100 Hz...

The time course photodegradation of the Nordic aquatic fulvic and humic acids and Suwannee River XAD-4 acids subjected to UV irradiation with an unfiltered medium pressure mercury lamp was studied by liquid-state 13C nuclear magnetic resonance. Photodecarboxylation was a significant pathway in all cases. Decreases in ketone, aromatic, and O-alkyl carbons were observed throughout the course of t...

Polychlorinated dibenzothiophenes (PCDTs) in sediment, soil, and fly ash samples collected in Japan were analyzed and their dioxin-like endocrine-disruption potential and photodegradability investigated. PCDTs were detected in all three types of sample, although the concentrations were lower than those of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). An Ah...

Pyrrole monomer was chemically polymerized onto SrCO₃-Sr(OH)₂ powders to obtain SrCO₃-Sr(OH)₂/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB). The material was characterized by Fourier transform infrared (FTIR) spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD). It was observed from transmission electronic microscopy (TEM...

A new type of [Bi6O6(OH)3](NO3)3·1.5H2O sheets photocatalyst was synthesized via a hydrothermal route. The photocatalytic properties were characterized by SEM, TEM, XRD and UV spectroscopy. It exhibited slightly better photocatalytic activity on phenol degradation than that of classic TiO2 P25 under UV illumination. Hydroquinone, catechol, resorcinol, and benzoquinone were identified as photode...

We have studied photoinduced reduction of absorption and emission in p3ht, a semiconducting polymer, and found that the rate of photodegradation (destruction of the constituent thiophene rings) does not correlate with the luminescence intensity and, correspondingly, does not depend on the excited state concentration. This conclusion rules out Purcell enhancement of radiative decay rate as a pos...