Die Peptisationserscheinungen in Gerbstofflösungen

Ohne Zusammenfassung     

Zur Bestimmung des Ozons

Ohne Zusammenfassung     

Formation of the pore structure in xerogel films based on ultra-high-molecular-weight polyethylene and multiwall carbon nanotubes

The fundamental aspect of the pore structure formation in composite films based on ultra-high-molecular-weight polyethylene and multiwall carbon nanotubes were studied by IR spectroscopy, mercury porosimetry, scanning electron microscopy, and differential scanning calorimetry in relation to the degree of filling.     

Ueber Mogdad-Kaffee

Ohne Zusammenfassung     

A new photometric method for the determination of chymotrypsin in stool

Conclusions The proposed method offers the following advantages:a) high reactivity of the enzyme; b) need for small sample volume, thus absorption from suspended particles does not interfere and c) nearly complete solubilization of particle bound enzyme thus allowing automated analysis with the supernatant after centrifugation.

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Neue photometrische Methode zur Chymotrypsinbestimmung im Stuhl

     

Dissection of Environmental Changes at the Cytoplasmic Surface of Light‐activated Bacteriorhodopsin and Visual Rhodopsin: Sequence of Spectrally Silent Steps†

The physico‐chemical properties as well as the conformation of the cytoplasmic surface of the 7‐helix retinal proteins bacteriorhodopsin (bR) and visual rhodopsin change upon light activation. A recent study found evidence for a transient softening of bR in its key intermediate M [Pieper et al. (2008) Phys. Rev. Lett. 100 , 228103] as a direct proof for the functional significance of protein flexibility. In this report we compare environmental and flexibility changes at the cytoplasmic surface of light‐activated bR and rhodopsin detected by time‐resolved fluorescence spectroscopy. The changes in fluorescence of covalently bound fluorescent probes and protein real‐time dynamics were investigated. We found that in fluorescently labeled bR and rhodopsin the intensity of fluorescein and Atto647 increased upon formation of the key intermediates M and metarhodopsin‐II, respectively, suggesting different surface properties compared to the dark state. Furthermore, time‐resolved fluorescence anisotropy experiments reveal an increase in steric restriction of loop flexibility because of changes in the surrounding protein environment in both the M‐intermediate as well as the active metarhodopsin‐II state. The kinetics of the fluorescence changes at the rhodopsin surface uncover multiple transitions, suggesting metarhodopsin‐II substates with different surface properties. Proton uptake from the aqueous bulk phase correlates with the first transition, while late proton release seems to parallel the second transition. The last transition between states of different surface properties correlates with metarhodopsin‐II decay.