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...

We study the effect of an external magnetic field on coherent backscattering of light from a cold rubidium vapor. We observe that the backscattering enhancement factor can be increased with B. This surprising behavior shows that the coherence length of the system can be increased by adding a magnetic field, in sharp contrast with usual situations. This is mainly due to the lifting of the degene...

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 ...

Accurate measurements of water vapor in the Arctic winter, either in situ or remote, are difficult to achieve. These measurements are important to studies in infrared radiative transfer. To focus on measurements during cold temperatures (< 20oC) and low amounts of vapor (Precipitable Water Vapor, 5 mm), an Intensive Operating Period (IOP) was conducted at the U.S. Department of Energy’s Atmosph...

The aim of this work is to bring forward a new style heat exchanger about hollow fiber membrane module, and to analyze the performance which can expectantly be applied in the lithium bromide absorption refrigeration system. Polyvinylidene fluoride hollow fiber membrane module was adopted as the new style solution heat exchanger, hot feed solution from the generator flowed into the lumen side of...

This study investigated the effects of increasing mercury (Hg) concentration on early developmental stages of sea urchin, Echinomethra mathaei, as a bioindicator. The toxicity test was carried out after the gamete released induction and fertilization in six concentrations of mercury within the range of 4, 8, 16, 32, 64 and 128 µg/L. Embryos samples were incubated for 30 h in control and test so...