We show that in experimental atomic force microscopy studies of the lifetime distribution of mechanically stressed folded proteins the effects of externally applied fluctuations cannot be distinguished from those of internally present fluctuations. In certain circumstances this leads to artificially nonexponential lifetime distributions, which can be misinterpreted as a signature of protein com...

in this study, 60 composite samples of dill and onion from two different cultivated areas in khozestan province, iran, were collected and analyzed for the presence and determination of lead and cadmium by flame atomic absorption spectrometry. samples were burned according to aoac at 450 °c, and the residue was dissolved in nitric acid. lead and cadmium contents were determined using calibration...

background: this study was carried out to determination of heavy metals (cd, cr, cu, fe, pb, ni and zn) concentration in upstream and downstream of the entry of the wastewater (untreated urban, traditional slaughterhouse waste, leachate from solid wastes has accumulated in river and  run off waters flowing across the city ) to the tembi river. methods: samples were collected for 1 year, before ...

a new method for the determination of trace copper(ii) in food samples by cloud point extraction(cpe) combined with flame atomic absorption spectrometry(faas) is presented and evaluated. the method is based on the fact that hydrophobic complex of copper(ii) with sodium diethyldithiocarbamate (ddtc) was formed at ph 6.0 and subsequently the hydrophobic complex was extracted into surfactant-rich ...

a novel, magnetic silica sorbent with polyelectrolyte multilayers (pems) on its surface was prepared, and was used for magnetic solid phase extraction (mspe) of trace a+ via flame atomic absorption spectrometry (faas). the experimental parameters for the mspe procedure, such as the ph, type, and concentration of eluent, ultrasonic time and effects of co-existing ions were investigated. the dete...

The present research work discussed the development of a simple, sensitive, rapid, accurate, precise and economical UV Spectrophotometric method for the Validation of Oseltamivir Phosphate in bulk and pharmaceutical dosage form which is based on the measurement of absorption maxima at 217 nm. Double beam U.V visible spectrophotometers, Shimadzu, Kyoto, Japan. Model UV1800 with 1cm matched quart...