Differences in litter quality, microbial activity or abiotic conditions cannot fully account for the variability in decomposition rates observed in semiarid ecosystems. Here we tested the role of variation in litter quality, water supply, and UV radiation as drivers of litter decomposition in arid lands. And show that carry-over effects of litter photodegradation during dry periods can regulate...

The lifetimes of the excited state of free nucleobases were measured in the gas phase for the first time. They are, respectively, 1.0 and 0.8 ps for the purine bases adenine (shown above) and guanine and 3.2, 2.4, and 6.4 ps for the pyrimidine bases cytosine, uracil, and thymine at 267 nm. The longer lifetimes of the pyrimidine bases may be associated with their higher propensity toward photode...

A novel analytical method for atmospheric polycyclic aromatic hydrocarbons (PAHs) was developed based on laser induced fluorescence (LIF) of samples on quartz multi-channel polydimethylsiloxane traps. A tunable dye laser with a frequency doubling crystal provided the excitation radiation, and a double monochromator with a photomultiplier tube detected emitted fluorescence. The method allowed fo...

background and objectives: analytical methods for volatile organic compounds (vocs) in different samples need extraction of compounds, by applying hazardous solvents. solid phase micro-extraction (spme) is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of vocs at a very good sensitivity without the use of any organic solvent. vocs...

background: determination of organic pollutants usually requires extraction of the pollutants from samples, using hazard­ous solvent. solid phase micro-extraction (spme) is a solvent-free equilibrium extraction method, in which, proper calibra­tion can allow quantitative measurements of organic pollutants at a very good sensitivity without the use of any organic sol­vent. because individual voc...

acetonitrile used as a solvent in manufactures and affects to central nervous system from inhalation exposure. the aim of this study was to develop a micro-solid phase extraction method for  the determination of acetonitrile in the air matrix. the sampling was performed with a small diameter fused silica fiber coated with a thin film of stationary phase and was subsequently desorbed and analyze...

Nifedipine (NIF) a 1, 4-dihydropyridine calcium channel antagonist, undergoes photodegradation to nitroso analogues of dehydronifedipine (NDNIF) when exposed to sunlight. Photodegradation products of NIF have no clinical activity, so different formulations of NIF must remain unchanged. If NIF preparations become unstable in exposure to light, they could cause therapeutic failure. The present st...

In this paper, we have done the photodegradation of Methyl green dye in presence of prepared Ni0.10:La0.05:TiO2 nanocomposites. The nanocomposites of Ni0.10:La0.05:TiO2 was prepared by the solution impregnation method. The characterization of Synthesized TiO2 and Ni0.10:La0.05:TiO2 nanocomposites were done by X-Ray Diffractometer, SEM, TEM, UVVis, FT-IR, Band gap energy and BET. The photocataly...

Nifedipine (NIF) a 1, 4-dihydropyridine calcium channel antagonist, undergoes photodegradation to nitroso analogues of dehydronifedipine (NDNIF) when exposed to sunlight. Photodegradation products of NIF have no clinical activity, so different formulations of NIF must remain unchanged. If NIF preparations become unstable in exposure to light, they could cause therapeutic failure. The present st...