Proteome analysis of a plasma membrane-enriched fraction at the placental feto-maternal barrier

Purpose : We want to identify proteins that are part of or associated with the plasma membrane of the human feto‐maternal barrier, which is crucially important for nutrient, gas, and waste exchange between the mother and the fetus. All transfer processes occur through one specialized endothelial cell layer, the multinuclear syncytiotrophoblast (STB). Specifically, the apical plasma membrane of the STB interacts with the maternal blood and is the site of initial transport processes across the placenta. Experimental design : We used a proteomic approach that employed the enrichment of apical STB membranes isolated from healthy placentae by ultracentrifugation and saccharose gradient centrifugation steps in combination with 1‐D SDS‐PAGE and ESI‐MS analysis. Results : We identified 296 different proteins, 175 of which were integral and peripheral membrane proteins, partially containing 1–12 transmembrane domains or lipid anchors. One hundred and sixty‐one proteins (54%) were allocated to the plasma membrane. Conclusions and clinical relevance : A high number of transporters, receptors, and proteins involved in signal transduction processes and vesicular trafficking were identified for the first time at the feto‐maternal barrier. Our results are valuable sources for further studies of the cell physiology of the healthy placenta at the time of birth or the pathophysiology of several pregnancy disorders.     

Projective virtual reality as a basis for on‐line control of complex systems‐not only‐over the internet

Already in 1994 the term Projective Virtual Reality was coined and a first implementation was used to control a complex multirobot system in Germany over the Internet from California. Building on this foundation, the general aim of the development of virtual reality technology for automation applications at the Institute of Robotics Research (IRF) today is to provide the framework for Projective Virtual Reality for a broad range of applications. The general idea of Projective Virtual Reality is to allow users to “project” actions carried out in the virtual world into the real world by means of robots or other means of automation. The framework is based on a task‐oriented approach which builds on the “task deduction” capabilities of a newly developed virtual reality system and a task planning component. The advantage of this approach is that robots which work at great distances from the control station can be controlled as easily and intuitively as robots that work right next to the control station. Robot control technology now provides the user in the virtual world with a “prolonged arm” into the physical environment, thus paving the way for intuitive control of complex systems over the Internet—and in general for a new quality of user‐friendly man‐machine interfaces for automation applications. Lately, this work has been enhanced by a new structure that allows one to distribute the virtual reality application over multiple computers on a network. With this new feature, it is now possible for multiple users to share the same virtual room, although they may physically be thousands of miles apart. They only need an Internet connection to share this new experience. Lately, the network distribution techniques have been further developed to not just allow users to cooperate over networked PCs but also to be able to set up a panorama projection or a cave running of a networked cluster of PCs. This approach cuts down the costs for such a high‐end visualization environment drastically and allows for a new range of applications. © 2005 Wiley Periodicals, Inc.     

On the modelling of bubbly flow in vertical pipes

To qualify CFD codes for two-phase flows, they have to be equipped with constitutive models standing for the interaction between the gaseous and the liquid phases. In case of bubbly flow this particularly concerns the forces acting on the bubbles and bubble coalescence and break-up. Applying a two fluid approach, besides the drag forces describing the momentum exchange in flow direction, the non-drag forces acting perpendicular to the flow direction play an important role for the development of the flow structure. Gas–liquid flow in vertical pipes is a very good object for studying the corresponding phenomena. Here, the bubbles move under clear boundary conditions, resulting in a shear field of nearly constant structure where the bubbles rise for a comparatively long time. The evolution of the flow within the pipe depends on a very complex interaction between bubble forces and bubble coalescence and break-up, e.g. the lift-force, which strongly influences the radial distribution of the bubbles, changes its sign depending on the bubble diameter. The consequence is the radial separation of small and large bubbles. Neglecting this phenomenon, models are not able to describe the correct flow structure. Extensive experiments measuring the radial gas volume fraction distribution, the bubble size distribution and the radial residence of bubbles dependent on their size were determined for different distances from the gas injection. Basing on these experiments the applicability and the limits for the simulation of bubble flow with current CFD-codes are demonstrated, using the simulation of vertical pipe flow with CFX-4 as an example. Using a simplified model focusing particularly on the radial phenomena described above, parametric studies were conducted. They give an indication for necessary improvements of the codes. Finally a possible way for the improvement of the CFD-codes is shown.     

Untersuchungen zur Haftungsbeeinflussung von Pigmentdrucken durch UV-Laser-Behandlung

Investigations on Adhesion of Pigment Printings by UV-Laser Treatment Investigations on the influence of UV-laser treatment of polyethyleneterephthalate and polyamide fibers and foils on the adhesion properties of pigment printings are presented. It could be shown that even irradiation with low energy densities and low number of pulses applied increases binder film adhesion very efficiently. Some interpretations of the laser action upon adhesion improvement related to surface modification are presented.     

Chemical Structure of <Emphasis Type="Italic">Bacteriovorax stolpii</Emphasis> Lipid A

Bdellovibrionales is a phylogenetically diverse group of predatory prokaryotes, which consists of the two families Bdellovibrionaceae and Bacteriovoracaceae. We describe LPS and lipid A of the type strain Bacteriovorax stolpii DSM 12778, representing the first characterized endotoxin of a Bacteriovoracaceae member. It has a smooth form LPS, which was identified by SDS-polyacrylamide gel electrophoresis. The lipid A structure was determined by combined gas chromatography–mass spectrometry, electrospray ionization mass spectrometry and NMR spectroscopy. Its backbone consists of two β-(1 → 6)-linked 2,3-diamino-2,3-dideoxy-d-glucopyranoses (GlcpN3N) carrying a pyrophosphoethanolamine at O-4′ of the non-reducing sugar and a phosphate group linked to O-1 of the reducing GlcpN3N. Positions 2, 3, 2′ and 3′ of the two GlcpN3N are acylated with primary 3-hydroxy fatty acids and one of those carries a secondary fatty acid.     

Curcumin‐Derived Pyrazoles and Isoxazoles: Swiss Army Knives or Blunt Tools for Alzheimer's Disease?

Curcumin binds to the amyloid beta peptide (Abeta) and inhibits or modulates amyloid precursor protein (APP) metabolism. Therefore, curcumin-derived isoxazoles and pyrazoles were synthesized to minimize the metal chelation properties of curcumin. The decreased rotational freedom and absence of stereoisomers was predicted to enhance affinity toward Abeta(42) aggregates. Accordingly, replacement of the 1,3-dicarbonyl moiety with isosteric heterocycles turned curcumin analogue isoxazoles and pyrazoles into potent ligands of fibrillar Abeta(42) aggregates. Additionally, several compounds are potent inhibitors of tau protein aggregation and depolymerized tau protein aggregates at low micromolar concentrations.     

Zerstörungsfreie Prüfung von Polymeren mittels photothermischer Meßmethoden. 2. Photoakustische untersuchungen von Polyesterfärbungen in Abhängigkeit von der Farbstoffkonzentration und der Oberflächenrauheit

The determination of dyestuff concentration in dark and saturated dyed textiles poses great problems to conventional analytical methods. In this work the use of photoacoustic spectroscopy as analytical tool is systematically investigated by comparing measurements of samples with different dyestuff concentrations. The experimental data can be fitted to a modified Kubelka-Munk function which shows a linear relationship to the dyestuff concentration in a wider range than the reflection spectroscopy. The influence of the surface structure to the photoacoustic signal is investigated.     

Mechanische Eigenschaften von Polyesterfasern bei kurzzeitiger Zugbeanspruchung, 1. Aufbau eines Meßplatzes für schnelle Zugbeanspruchung

The stress-strain behaviour of filament yarns has been determined by variation of strain rates from 10^?1 up to 10⁵%/s. Strain rates up to 10%/s are obtained with a tensile testing machine. The higher strain rates up to 10⁵%/s are obtained with an apparatus using a falling weight by variation of the height of fall and the length of the yarn. Because of the high-speed impact and time of strain/influence down to 10^?4 s together with the variation of the height of fall between 0,6 and 166 cm a profound discussion of errors is necessary.