Reverse Mapping of Coarse Grained Polyglutamine Conformations from PRIME20 Sampling.

An inverse coarse-graining protocol is presented for generating and validating atomistic structures of large (bio-) molecules from conformations obtained via a coarse-grained sampling method. Specifically, the protocol is implemented and tested based on the (coarse-grained) PRIME20 protein model (P20/SAMC), and the resulting all-atom conformations are simulated using conventional biomolecular force fields. The phase space sampling at the coarse-grained level is performed with a stochastical approximation Monte Carlo approach. The method is applied to a series of polypeptides, specifically dimers of polyglutamine with varying chain length in aqueous solution. The majority (>70 %) of the conformations obtained from the coarse-grained peptide model can successfully be mapped back to atomistic structures that remain conformationally stable during 10 ns of molecular dynamics simulations. This work can be seen as the first step towards the overarching goal of improving our understanding of protein aggregation phenomena through simulation methods.

Mode shaping in semiconductor broad area lasers by monolithically integrated phase structures.

By broadening the stripe width of the active waveguide region, it is possible to extract high optical powers from semiconductor broad area lasers. However, a weak output beam quality, optical filamentation, and high peak power densities will result, which are invoked by the amplification of higher order modes. We show an approach to influence the optical field inside the resonator by integrating optical phase structures directly into the waveguide. Those elements offer the possibility to enlarge the active gain area for the desired fundamental laser mode, while additional diffraction losses for higher order modes are generated, thus achieving an improved beam quality. We report on considerations in designing those elements and demonstrate a first experimental realization.

[Without risks and side effects? Product advertisements in dental journals]. / Ohne Risiko und Nebenwirkung? Produktwerbung in zahnmedizinischen Zeitschriften.

We examined number, size, design, and scientific approach of advertisements published in three dental journals between 1970 and 2004. For this purpose, the Schweizer Monatsschrift für Zahnmedizin (SMfZ), Zahnärztliche Mitteilungen (ZM; Ger many), and The Journal of the American Dental Association (JADA) were chosen. The January and July issues of each of the 35 volumes were analyzed. Of 28,711 pages, 7265.5 were identified as advertisements (JADA: 29.9%, SMfZ: 24.8%, ZM: 13.7%). While whole-page ads dominated in JADA (87.2%) and SMfZ (68.9%), ad-sizes were more balanced in ZM. During the observation period, the use of photographs increased, while that of drawings decreased. Images of products dominated as compared to pictures of the orofacial region. Citations from study results (SMfZ 3.3%: ZM 2.5%; JADA 5.5%) and diagrams/tables (SMfZ: 3.2%; ZM: 1.0%; JADA: 4.5%) were rarely used, and an appreciable number of cited references could not be identified (SMfZ: 16%, ZM: 18%). More than 80% of the identifiable cited references corroborated the claim made in the advertisement. However, a critical attitude towards ads in dental journals appears justified.