Fully reversible procedure for silver staining improves densitometry of complex mixtures of biopolymers resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis

Due to its high sensitivity, silver staining is a widely popular method for the revelation of biopolymers separated by both native and denaturing electrophoresis. A step-by-step method for the destaining and restaining of overdeveloped/overloaded silver-stained bands is described that is applicable to both proteins and nucleic acids. The procedure significantly improves densitometric analysis of gels that have been silver stained with either commercial kits or solutions made in-house. The method permits reproducible densitometry of silver-stained gels and allows quantification of both main and minor components in complex mixture of molecules resolved on the same gel slab. All steps may be interrupted and are readily reversible, allowing for facile densitometric analyses and photographic recording under optimized conditions. Furthermore, common artifacts such as differential staining of the two gel surfaces, localized uneven yellow-ochre background, and the presence of fold marks and fingerprints can be easily removed.     

A new method for measuring atomic diffusion constant in non-crystalline materials using mössbauer spectroscopy

A new method for measuring atomic diffusion is presented. We prepare artificially modulated structure of Fe₇₀ Si₃₀/Si and we follow the time variation of magnetic iron atom by Mössbauer spectroscopy. It is possible to show that this concentration is related to an apparent difusion constant \(\tilde D_\Lambda \) by $$Ln\frac{{C_m (t)}}{{C_m (o)}} = - \frac{{8\pi ^2 }}{{\Lambda ^2 }} \tilde D_\Lambda t$$ where Λ is the wavelength of the modulation. The interdiffusion constant is found to be 9.5±0.3 . 10^?26 m². s^?1 at 420 K and 1.85±0.1 . 10^?25 m².s^?1 at 450 K.