Photooxidation von Leukofarbstoffen. X. Untersuchungen zur Photooxidation von Di-kalium-anthracen-9,10-ylen-bis-sulfat

Photooxidation of Leuco Dyes. X. Investigation of the Photooxidation of Di-potassiumanthracene 9,10-ylene-di-sulfate Photolysis of the title compound (DHAE) in water or ethanol produces anthraquinone and anthrone. In deoxygenated solutions 9,10-dihydroxyanthracene is detected as a long lived intermediate. Laser and conventional flash photolysis reveals three short-lived transients with lifetimes of 200 ns, 2 and 410 ms. Different temperature dependencies are observed for the fluorescence and the photolysis quantum yields. This is interpreted by two successive thermally activated processes: photohomolysis of O S bond and escape of the radical pair from the solvent cage. The results are discussed with the help of a reaction scheme proposed for the photolysis of DHAE.     

Lineament mapping for groundwater resource assessment: A comparison of digital Synthetic Aperture Radar (SAR) imagery and stereoscopic Large Format Camera (LFC) photographs in the Red Sea Hills,Sudan

The results of a comparative investigation of lineament mapping from stereoscopic Large Format Camera (LFC) photographs and from SIR-C L- and C-band Synthetic Aperture Radar (SAR) data are described. The lineament patterns are used to test a model developed by Koch (1993) of groundwater flow in the arid Red Sea Hills area of Sudan. Initial results show that the LFC imagery is most useful for mapping detailed fracture patterns while the combination of the L- and C-bands of the SIR-C Synthetic Aperture Radar is helpful in the location of major deep-seated fracture zones. The lineament patterns derived from LFC and SIR-C show strong N-S and E-W orientations, which correspond to the current tectonic configuration of the Red Sea rift system. The longer E-W trending features may be important from a regional hydro-geological point of view, whereas the shorter features are significant in that they interconnect the major faults.     

Submicron droplet formation in the human lung

The exhaled breath of humans contains droplets originating from the lung lining fluid. An analysis of these droplets for non-volatile proteinaceous biomarkers holds potential as a non-invasive diagnosis of lung diseases. To ease the interpretation of the diagnostic results, the source strength of the particles should be known und therefore an understanding of the particle generation process is required. It is assumed that during reopening of a collapsed terminal airway a liquid bridge of the lung lining fluid ruptures and droplets are generated. The objective of our experimental and theoretical study was to clarify the mechanisms of droplet generation for quiet breathing patterns by investigating in detail the number flux and the particle size distribution in the exhaled breath. The process of liquid film rupture is modelled by computational fluid dynamics analysis from which the droplet size distribution is calculated. In addition the number emission flux and the droplet size distribution are systematically measured in the exhaled breath of healthy volunteers. The strong increase of the particle emission flux with tidal volume and the good agreement between measured and calculated droplet number distribution both showing droplets primarily in the submicron range confirm the present hypothesis that reopening of collapsed airway structures associated with the rupture of a surfactant film is the physical mechanism of droplet generation. This was hypothesized previously in the literature.     

Dual-plane ultrafast limited-angle electron beam x-ray tomography

Electron beam x-ray tomography is an imaging technique, which can provide cross-sectional images of an object of interest with about 1 mm spatial resolution at frame rates of up to 10,000 frames per second. As a non-intrusive method it is especially suited for studying multiphase flows. For this purpose we devised an experimental limited-angle scan setup which utilizes linear beam deflection to generate radiographic projections. This setup was employed in the study of gas–liquid flow in an experimental flow loop operated at different liquid and gas flow rates. Electron-beam tomography images were compared with image data of a wire-mesh sensor. The latter is a fast but intrusive imaging device which is commonly used in gas–liquid flow imaging and achieves comparable frame rates but at lower spatial resolution. As a novelty we implemented a dual-plane limited-angle electron beam x-ray tomography which allows us to gain information about the phase velocities using cross-correlation data analysis.     

Impact of the coating process on the molecular structure of starch‐based barrier coatings

Molecular analysis of starch structure can be used to explain and predict changes in physical properties, such as water vapor and oxygen barrier properties in packaging materials. Solution casting is a widely used technique to create films from starch formulations. This study compared the molecular properties of these standard films with those of experimental coatings applied to paper in laboratory‐scale and pilot‐scale trials, with all three techniques using the same starch formulation. The results revealed large differences in molecular structure, i.e., cross‐linking and hydrolysis, between films and coatings. The main differences were due to the shorter drying time allowed to laboratory‐scale coatings and the accelerated drying process in pilot trials owing to the high energy output of infrared dryers. Furthermore, surface morphology was highly affected by the coating technique used, with a rougher surface and many pinholes occurring in pilot‐scale coatings, giving lower water vapor permeability than laboratory‐scale coatings. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41190.     

Mechanistic Insights into Cyclic Peptide Generation by DnaE Split-Inteins through Quantitative and Structural Investigation

Inteins carry out protein-splicing reactions, which are used in protein chemistry, protein engineering and biotechnological applications. Rearrangement of the order of the domains in split-inteins results in head-to-tail cyclisation of the target sequence, which can be used for genetic encoding and expression of libraries of cyclic peptides (CPs). The efficiency of the splicing reaction depends on the target sequence. Here we used mass spectrometry to assess in vivo cyclic peptide formation from different hexameric target sequences by the DnaE split-inteins from Synechocystis sp. and Nostoc punctiforme, revealing a strong impact of the target sequence and of the intein on the intracellular peptide concentration. Furthermore, we determined the crystal structures of their pre-splicing complexes, which allowed us to identify F-block Asp17 as crucial for the DnaE-mediated splicing reaction.     

Planning Leguslation: 1963

Population projections for subcounty areas often are made by extrapolating past population trends. Although more sophisticated methods exist and population extrapolations long have been criticized for their weak theoretical foundations, they remain an extremely popular planning tool in part because constraints of data, time, funds, and expertise make the more sophisticated methods infeasible. The objective of this research was to document the level of accuracy of a number of commonly used extrapolative methods and, thereby, to offer suggestions for their use. For example, exponential extrapolation was found to be most accurate for rapidly growing or declining areas, whereas linear extrapolation was most accurate for moderately growing areas. More than thirty-five hundred simulated population projections for 1960 and 1970 were made for most of the methods being tested. Then the simulated projections were compared to the actual populations to measure percentage errors and tendencies to over- or underestimate. The results indicate that extrapolative methods may yield sufficiently accurate projections for many planning purposes.