Modifizierung der Struktur und optoelektronischen Eigenschaften durch Mischungsbildung und Druck

An kolumnar-diskotischen Triphenylenderivaten wurde der Einfluß von hydrostatischem Druck und binärer Mischungsbildung auf Struktur und optoelektronischen Eigenschaften der flüssigkristallinen Phase untersucht. Dazu wurden Messungen mittels DSC, Polarisationsmikroskopie,Röntgenstrukturanalyse mit Synchrotronstrahlung, UV-VIS-Spektroskopie unter Druck und an orientierten Proben und DK-Messungen durchgeführt. Die Kompressibilitäten der flüssigkristallinen Phase wurden aus dem Experiment berechnet. Unter anderem hatte die binäre Mischungsbildung einen Einfluß auf die Morphologie und die Kristallisation der Triphenylene

Paper Session III-B - European Node 2 and 3 Space Station Contributions

The International Space Station requires three Nodes for the completion of the configuration. The first of these Nodes, designed and manufactured under National Aeronautics & Space Administration (NASA) contract, has already been launched successfully and is waiting for the assembly of further elements. As a little background, Nodes 2 & 3 were agreed to be designed and constructed in Europe in a Barter agreement between NASA and the European Space Agency (ESA) with the overall management assigned to the Italian Space Agency (ASI). Alenia Spazio (ALS) was awarded the overall prime contractor role. Necessitated by geographical return reasons within ESA programs, subsystem activities were given outside Italy even though this did not adhere to the classical role of prime contractor functions in an optimized standard program. With OHB-System winning the two major sub-contractor roles for the Secondary Structure and the Harness, we are now responsible for designing, manufacturing, and testing these subsystems for Nodes 2 & 3 in an international team approach

Effects of Orthogonal Rotating Electric Fields on Electrospinning Process

Electrospinning is a nanotechnology process whereby an external electric field is used to accelerate and stretch a charged polymer jet, so as to produce fibers with nanoscale diameters. In quest of a further reduction in the cross section of electrified jets hence of a better control on the morphology of the resulting electrospun fibers, we explore the effects of an external rotating electric field orthogonal to the jet direction. Through extensive particle simulations, it is shown that by a proper tuning of the electric field amplitude and frequency, a reduction of up to a $30 \%$ in the aforementioned radius can be obtained, thereby opening new perspectives in the design of future ultra-thin electrospun fibres. Applications can be envisaged in the fields of nanophotonic components as well as for designing new and improved filtration materials.Comment: 22 pages, 8 figure

Empirical Investigation on Agile Methods Usage: Issues Identified from Early Adopters in Malaysia

Agile Methods are a set of software practices that can help to produce products faster and at the same time deliver what customers want. Despite the benefits that Agile methods can deliver, however, we found few studies from the Southeast Asia region, particularly Malaysia. As a result, less empirical evidence can be obtained in the country making its implementation harder. To use a new method, experience from other practitioners is critical, which describes what is important, what is possible and what is not possible concerning Agile. We conducted a qualitative study to understand the issues faced by early adopters in Malaysia where Agile methods are still relatively new. The initial study involves 13 participants including project managers, CEOs, founders and software developers from seven organisations. Our study has shown that social and human aspects are important when using Agile methods. While technical aspects have always been considered to exist in software development, we found these factors to be less important when using Agile methods. The results obtained can serve as guidelines to practitioners in the country and the neighbouring regions

Influence of Poly(L-Lactic Acid) Nanofibers and BMP-2–Containing Poly(L-Lactic Acid) Nanofibers on Growth and Osteogenic Differentiation of Human Mesenchymal Stem Cells

The aim of this study was to characterize synthetic poly-(L-lactic acid) (PLLA) nanofibers concerning their ability to promote growth and osteogenic differentiation of stem cells in vitro, as well as to test their suitability as a carrier system for growth factors. Fiber matrices composed of PLLA or BMP-2–incorporated PLLA were seeded with human mesenchymal stem cells and cultivated over a period of 22 days under growth and osteoinductive conditions, and analyzed during the course of culture, with respect to gene expression of alkaline phosphatase (ALP), osteocalcin (OC), and collagen I (COL-I). Furthermore, COL-I and OC deposition, as well as cell densities and proliferation, were analyzed using fluorescence microscopy. Although the presence of nanofibers diminished the dexamethasone-induced proliferation, there were no differences in cell densities or deposition of either COL-I or OC after 22 days of culture. The gene expression of ALP, OC, and COL-I decreased in the initial phase of cell cultivation on PLLA nanofibers as compared to cover slip control, but normalized during the course of cultivation. The initial down-regulation was not observed when BMP-2 was directly incorporated into PLLA nanofibers by electrospinning, indicating that growth factors like BMP-2 might survive the spinning process in a bioactive form

The Anthracosia Shales from the Intra-Sudetic Basin in the light of organic geochemistry proxies : preliminary results of bitumen study

The lacustrine Anthracosia Shales of the Intra-Sudetic Basin are sediments that have become the subject of interest due to their dark colour, indicating an increased content of dispersed organic matter. The published data concern the characteristics of macerals, vitrinite reflectance, the results of Rock-Eval pyrolysis and the results of palynological tests. The above studies were supplemented with the current analysis of the extracted bitumens. The results of the distribution of n-alkanes in the Anthracosia Shales corresponds with the results of macerals and palynology. The dominance of short-chain homologues indicates the microbial-algal origin of the organic matter. Some contribution of terrestrial organic matter is not excluded. Three lithofacies intervals differing geochemically have been distinguished: I - dark grey calcareous claystones rich in aliphatic compounds of microbial and algal origin; II - grey mudstones with siderites containing a lower amount of aliphatic compounds in favour of polar and aromatic compounds; III -weakly calcareous mudstones and sandstones, poor in terrestrial organic matter. The distribution of n-alkanes, phenanthrene and methylphenanthrenes (CPI, MPI, MPR, PP1) shown that the maturity of the organic substance is within the oil window. This is further supported by the Rock-Eval data and vitrinite reflectance values

Characterization of a PLLA-Collagen I Blend Nanofiber Scaffold with Respect to Growth and Osteogenic Differentiation of Human Mesenchymal Stem Cells

The aim of this study was to enhance synthetic poly(L-lactic acid) (PLLA) nanofibers by blending with collagen I (COLI) in order to improve their ability to promote growth and osteogenic differentiation of stem cells in vitro. Fiber matrices composed of PLLA and COLI in different ratios were characterized with respect to their morphology, as well as their ability to promote growth of human mesenchymal stem cells (hMSC) over a period of 22 days. Furthermore, the course of differentiation was analyzed by gene expression of alkaline phosphatase (ALP), osteocalcin (OC), and COLI. The PLLA-COLI blend nanofibers presented themselves with a relatively smooth surface. They were more hydrophilic as compared to PLLA nanofibers alone and formed a gel-like structure with a stable nanofiber backbone when incubated in aqueous solutions. We examined nanofibers composed of different PLLA and COLI ratios. A composition of 4:1 ratio of PLLA:COLI showed the best results. When hMSC were cultured on the PLLA-COLI nanofiber blend, growth as well as osteoblast differentiation (determined as gene expression of ALP, OC, and COLI) was enhanced when compared to PLLA nanofibers alone. Therefore, the blending of PLLA with COLI might be a suitable tool to enhance PLLA nanofibers with respect to bone tissue engineering