Influence of acid chain length on the properties of TiO2 prepared by sol-gel method and LC-MS studies of methylene blue photodegradation.

Nano-sized titanium dioxide photocatalysts were synthesized by hybrid hydrolytic nonhydrolytic sol-gel method using aliphatic organic acid templates to study the effect of chain length on their properties. X-ray diffraction pattern indicated crystalline anatase phase. The Barrett-Joyner-Halenda surface area measurement gave surface area ranging from 98.4 to 205.5m(2)/g and was found to be dependent on the chain length of the aliphatic acid. The longer chain acids rendered the material with high surface area. The organic acids acted as bidentate ligand and a surfactant in controlling the size and the mesoporosity. The size of the TiO2 nanoparticulate was found to be in the range of 10-18nm. The catalyst prepared by employing long chain acids octanoic acid and palmitic acid had smaller size, narrow pore radius, higher surface area and showed better photocatalytic activity than the commercially available Degussa P25 catalyst for the degradation of methylene blue dye. A new intermediate was identified by tandem liquid chromatography mass spectrometry studies during the degradation of methylene blue solution.

GRP78 clustering at the cell surface of neurons transduces the action of exogenous alpha-synuclein.

Mutation or multiplication of the alpha-synuclein (Syn)-encoding gene is frequent cause of early onset Parkinson's disease (PD). Recent evidences point to the pathogenic role of excess Syn also in sporadic PD. Syn is a cytosolic protein, which has been shown to be released from neurons. Here we provide evidence that extracellular Syn induces an increase in surface-exposed glucose-related protein of 78 kDa (GRP78), which becomes clustered in microdomains of the neuronal plasma membrane. Upon interacting with Syn, GRP78 activates a signaling cascade leading to cofilin 1 inactivation and stabilization of microfilaments, thus affecting morphology and dynamics of actin cytoskeleton in cultured neurons. Downregulation of GRP78 abolishes the activity of exogenous Syn, indicating that it is the primary target of Syn. Inactivation of cofilin 1 and stabilization of actin cytoskeleton are present also in fibroblasts derived from genetic PD patients, which show a dramatic increase in stress fibers. Similar changes are displayed by control cells incubated with the medium of PD fibroblasts, only when Syn is present. The accumulation of Syn in the extracellular milieu, its interaction with the plasma membrane and Syn-driven clustering of GRP78 appear, therefore, responsible for the dysregulation of actin turnover, leading to early deficits in synaptic function that precede neurodegeneration.

Variations in daily urinary-N of adult rats on varying protein levels.

The pattern of daily fluctuations in urinary nitrogen (UN) of adult male albino rats fed on varying protein levels was studied. In the first experiment, two protein levels (7% and 13%) were provided, using two rats at each level for 10 weeks. In the second experiment, a submaintenance protein level (4%) was added, and finally, an excess protein level (30%) was tested on two rats. Time series analysis was used to study the underlying pattern of daily fluctuations in the UN of adult rats maintaining body weights on a near constant intake. It is shown that the behavior of daily fluctuations as reflected by serial correlation is in fact affected by the protein level fed. It was observed that on the 7% and 13% levels, the serial correlations were significant and the process could be identified as an autoregressive process of order one. At very low (4%) as well as very high (30%) levels of protein, however, the daily fluctuations were random. The behavior of daily fluctuations in UN was thus observed to be affected by the level of protein fed.