Lifetime of the two-phonon vibrational state in232Th

We report on a measurement of the lifetime of the 1414 keV state in²³²Th by the Doppler-shift recoil-distance method. This 4⁺ state shows all characteristics of a nearly-harmonic two-phonon-vibrational excitation. The result for the B(E2) value obtained from the lifetime,=3.2 ± 0.7 ps, is in agreement with an earlier estimate of the collectivity from Coulomb-excitation yields and supports the interpretation of the 1414 keV state as a two-phonon-vibrational excitation.We would like to thank the accelerator crew of the Max-Planck-Institut für Kernphysik for the excellent running conditions they maintain. We are also indebted to Dr. H.J. Maier, University Munich for supplying us with the²³²Th targets. This work was supported by the Bundesminister für Forschung und Technologie under contract numbers 06BN601 and 06HD5251.     

The interaction of cysteine with chromium(VI) ions under UV irradiation

In 0.1 M phosphate buffer (pH 7.2), the interaction of chromium(VI) with cysteine in the presence and absence of UV irradiation was studied by cyclic voltammetry and electronic spectroscopy techniques. The reduction of Cr(VI) by cysteine takes place through the formation of Cr(VI)-thioester intermediate. On the cyclic voltammograms of cysteine and Cr(VI) mixture, the peaks at -0.315 and -0.800 V were observed, and these peaks are corresponding to the reduction of Cr(VI)-thioester and thiyl radical, respectively. In the cysteine solution exposed to UV irradiation, the formation of free cystine was observed at -0.792 V. In the cysteine and Cr(VI) mixture exposed to UV irradiation, the peak current of thiyl radical increases while the peak current of Cr(VI)-thioester reaches a maximum at 15 min and then decreases by increasing UV irradiation time. The formation of the thioester in the reaction between Cr(VI) and cysteine in aqueous media has been studied by monitoring the decrease of Cr(VI) at 370 nm. It was observed that the reaction is catalyzed by the UV irradiation of the Cr(VI) and cysteine mixture.     

Kinetics and mechanism of the C-S coupling reactions of aryl Grignard reagents with aryl arenesulfonates

The kinetics of the C-S coupling of arylmagnesium bromides with phenyl tosylate has been studied in THF: toluene at 90°C. The reaction is first order in Grignard reagent and first order in phenyl tosylate. Kinetic data, Hammett relationship and activation parameters are consistent with a nucleophilic addition mechanism involving rate determining attack of carbanion to sulfonyl group followed by a fast phenoxide group leaving.      

Photoinduced Amyloid Fibril Degradation for Controlled Cell Patterning

Amyloid-like fibrils are a special class of self-assembling peptides that emerge as a promising nanomaterial with rich bioactivity for applications such as cell adhesion and growth. Unlike the extracellular matrix, the intrinsically stable amyloid-like fibrils do not respond nor adapt to stimuli of their natural environment. Here, a self-assembling motif (CKFKFQF), in which a photosensitive o-nitrobenzyl linker (PCL) is inserted, is designed. This peptide (CKFK-PCL-FQF) assembles into amyloid-like fibrils comparable to the unsubstituted CKFKFQF and reveals a strong response to UV-light. After UV irradiation, the secondary structure of the fibrils, fibril morphology, and bioactivity are lost. Thus, coating surfaces with the pre-formed fibrils and exposing them to UV-light through a photomask generate well-defined areas with patterns of intact and destroyed fibrillar morphology. The unexposed, fibril-coated surface areas retain their ability to support cell adhesion in culture, in contrast to the light-exposed regions, where the cell-supportive fibril morphology is destroyed. Consequently, the photoresponsive peptide nanofibrils provide a facile and efficient way of cell patterning, exemplarily demonstrated for A549, Chinese Hamster Ovary, and Raw Dual type cells. This study introduces photoresponsive amyloid-like fibrils as adaptive functional materials to precisely arrange cells on surfaces.     

Voltammetric and Docking Investigation of the Binding Interaction between (E)-1-[(2-Phenoxyphenylimino)methyl]naphthalen-2-ol and Calf Thymus DNA

Russian Journal of Electrochemistry - In vitro interaction between (E)-1-[(2-phenoxyphenylimino)methyl]naphthalen-2-ol (2-PPMN) and calf thymus DNA (ct-DNA) at physiological pH was investigated by...     

Correction to: An improved quasi-zero stiffness vibration isolation system utilizing dry friction damping

Nonlinear Dynamics - Equation 7 should appear as follows     

Betr?ge zur Kenntnis der Ligninbestimmung nach der Schwefels?uremethod

Ohne Zusammenfassung