Fluorescent chlorophyll catabolites (FCCs) are fleeting intermediates of chlorophyll breakdown, which is seen as an enzyme controlled detoxification process of the chlorophylls in plants. However, some plants accumulate large amounts of persistent FCCs, such as in senescent leaves and in peels of yellow bananas. The photophysical properties of such a persistent FCC (Me-sFCC) were investigated i...

The UV laser flash excitation of diphenylamine in methanol at 308 nm leads to similar triplet decay routes as those found previously for N-methyldiphenylamine and triphenylamine. The temperature dependence of the diphenylamine triplet decay shows that both ring closure to form triplet dihydrocarbazole and intersystem crossing back to the ground state take place. The Arrhenius parameters for the...

We present the first photoelectron spectroscopy measurements of quantum dots (semiconductor nanocrystals) in the gas phase. By coupling a nanoparticle aerosol source to a femtosecond velocity map imaging photoelectron spectrometer, we apply robust gas-phase photoelectron spectroscopy techniques to colloidal quantum dots, which typically must be studied in a liquid solvent or while bound to a su...

Quantum-size semiconductor microcrystallites of ZnCdS and CdS in aqueous and isopropanol solution were optically excited using intense sub-picosecond UV laser pump pulses. Broad-band optical probing monitored the yield of electron emission and the build-up of primary photochemical products. With typical pump fluences of femtosecond light pulses multiple photons are absorbed by one quantum-dot l...

This work shows that the addition of phenol and 2-propanol as model organic compounds significantly decreases the direct photolysis quantum yield of 4-chloro-2-methylphenoxyacetic acid (MCPA) upon UVB irradiation in aqueous solution. Laser flash photolysis data suggest that 2-propanol is able to decrease the formation of the MCPA excited states under irradiation. A decrease from 0.54 to 0.34 of...

Regulation of nonradiative dissipation of absorbed light energy in PSII is an indispensable process to avoid photoinhibition in plants. To dissect molecular mechanisms of the regulation, we identified Arabidopsis mutants with reduced quenching of Chl fluorescence using a fluorescence imaging system. By analyses of Chl fluorescence induction pattern in the light and quantum yield of both photosy...

Mexican lime is one of the commercial citrus cultivars in the world, which is commonly used as a citrus rootstock in the southern regions of Iran. This cultivar is one of the most sensitive citrus cultivars to cold stress and is used as a cold-sensitive plant in many citrus studies. This study aimed to investigate the effect of melatonin (0 and 500 μM), mannitol (0 and 50 μM), acetic acid (0 an...

The elimination of ranitidine (a pharmaceutical compound) has been carried out in the presence of UV-C radiation. After some preliminary experiments, it has been experienced the no influence of the gas nature (air or oxygen) bubbled in photolytic experiments. From simple photolysis experiments the quantum yield of this compound has been determined. Two photolytic approximation has been used, th...

UNLABELLED The water solubilization of nanoparticles is key for many applications in biomedicine. Despite the importance of surface functionalization, progress has been largely empirical and very few systematic studies have been performed. Here we report on the water solubilization of quantum dots using lipid encapsulation. We systematically evaluate the monodispersity, zeta potential, stabilit...