Kinetic interface roughening and magneto resistance of sputter-deposited Fe/Ni75B25 multilayers

The roughening of interfaces as a function of layer thickness and magneto transport properties have been investigated on sputter-deposited Fe/Ni₇₅B₂₅ multilayer films. X-ray reflectivity data were recorded for Ni₇₅B₂₅(72 nm) film and for [Fe(2 nm)/Ni₇₅B₂₅(2 nm)]₁₆ and [Fe(4 nm)/Ni₇₅B₂₅(4 nm)]₈ multilayer films. A power law dependence of the interfacial width of growing Fe/Ni₇₅B₂₅ interfaces was observed. The resulting growth exponents β were found to be in the range of 0.55–0.58 in the initial growth stage of the multilayer with lower Fe/Ni₇₅B₂₅ repetition thickness and at approximately 0.34 for multilayer with higher repetition thickness. The growth exponents were compared with theoretical calculations. High resolution electron microscopy revealed the columnar growth of the Fe/Ni₇₅B₂₅ multilayer. Additionally, an increase of magnetoresistance was observed by the multilayering of Ni₇₅B₂₅ films with Fe interlayers.     

Mineralization of biomimetically carboxymethylated collagen fibrils in a model dual membrane diffusion system

In the present work, we show for the first time, that N^?-carboxymethyllysine is the major product of the in vitro non-enzymatic glycation reaction between fibrillar collagen and glucuronic acid. Dual diffusion membrane system was effectively used for oriented crystal growth of octacalcium phosphate/hydroxyapatite on the biomimetically carboxymethylated collagen fibrils. We hypothesize that the function of biomimetically carboxymethylated collagen is to increase the local concentration of corresponding ions in such a way that a critical nucleus of ions can be formed, leading to the formation of the mineral under specific micro-environment conditions achieved by using diffusion membrane system.     

Interaction of SWCNT and PPTA with sulfuric acid—Compatibilization of two materials in a common solvent

The results of a calorimetric study on the melting and crystallization behavior of concentrated sulfuric acid containing dispersed single wall carbon nanotubes (SWCNT), dissolved water, and dissolved poly‐p‐phenyleneterphthalate (PPTA) polymer are presented. The measured reduction of the heat of crystallization is caused by the build‐up of an associated layer of structured acid molecules around SWCNT and PPTA. The freezing point depression is related to the number of dissolved species such as ions. It is shown that this theory accurately describes the experimental data for dissolved water and sulfur trioxide, but not for large molecules such as SWCNT. A mechanism for the interaction between sulfuric acid and SWCNT is proposed, based on preferred adsorption of sulfur trioxide and dissociation of sulfuric acid, leading to an increased number of dissolved low‐molecular‐weight species. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1914–1922, 2008     

Improved particle-packed HPLC/MS microchips for proteomic analysis

The influence of packing process parameters (packing pressure, application of ultrasound) and the stationary phase particle size (3.5 and 5 μm) on the chromatographic performance of HPLC/MS chips was systematically investigated for proteomic samples. First, reproducibility and detection limits of the separation were evaluated with a low‐complexity sample of tryptic BSA peptides. The influence of adsorbent packing quality on protein identification was then tested with a typical proteomics sample of high complexity, a human plasma protein fraction (Cohn fraction IV‐4). All HPLC/MS chips provided highly reproducible separations of these proteomic samples, but improved packing conditions and smaller particle sizes resulted in chromatograms with narrower peaks and correspondingly higher signal intensities. Improved separation performance increased the peak capacity, the number of identified peptides, and thus the sequence coverage in the proteomic samples, particularly for low sample amounts.     

Diamantoide. Chemie mit Nano‐Juwelen

Future of diamondoids. Although the class of diamondoids has been known for many decades, the renaissance of these molecular nanodiamonds has only begun very recently. In the last century there has already been a great deal of research work and some relevant applications in the area of adamantane (rarely diamantane or triamantane) but the higher diamondoids were virtually left unexplored. The selective chemical modification of diamondoids represents a formidable scientific challenge but inherits the potential for many advances and unique applications. While other nanoscale diamond materials often have problems with size distributions and purity, diamondoids possess welldefined structures and are of high purity. Only seven years after the first isolation of higher diamondoids from crude oil we conclude that research and development in this field proceeds at an amazing pace.