7 research outputs found
In Vitro Effect of Thiol- and Cysteine-Containing Compounds on the Immunological Reactivity of Human and Rhesus Monkey Lipoprotein(a)
No full textDevelopment and optimization of photopolymerizable slurries for the Lithography-based Ceramic Manufacturing process
No full textDie vorliegende Arbeit beschäftigt sich mit den, für den Lithography-based Ceramic Manufacturing (LCM) Prozess als Ausgangsmaterial dienenden, photopolymerisierbaren keramischen Schlickersystemen. Diese stellen kolloidale Suspensionen dar. Keramische Partikel sind mithilfe eines Dispergieradditivs in einem organischen Gemisch aus Lösungsmittel und Monomeren fein dispergiert. Ein Photoinitiator ermöglicht durch selektive Belichtung des Schlickers das schichtweise Aushärten und schlussendliche Strukturieren dreidimensionaler Formkörper. In einer abschließenden thermischen Behandlung wird die organische Matrix der Bauteile ausgebrannt und die Keramikpartikel zu einer dichten Keramik ( 99 % theor. Dichte) gesintert. Bauteile hergestellt im LCM Prozess zeichnen sich durch hohe Auflösung ( 99 % theor. density). Parts manufactured in the LCM process excel in high resolution (< 25 µm) as well as high surface quality. Slurry systems are covered for the dental ceramics zirconia, an oxide ceramic with good mechanical properties used for restorations in the posterior tooth region and lithium disilicate, a glass ceramic with tooth-like optical properties (translucency, color) used for highly aesthetic restorations in the anterior region. Furthermore, suspensions for the bioceramic tricalcium phosphate are examined. There are three main requirements to ceramic-filled slurries in the LCM process, long-time stability against sedimentation, stability against separation due to occuring shear forces, and an easy, time efficient debinding of the manufactured green bodies. For this purpose different approaches are pursued to enable a stable, flawless and reproducible production of parts out of high-performance ceramics. Through applying a thermoplastic component in existing slurry formulations instead of the diluent or by using fumed silica, an inorganic rheology additive, the ceramic slurries could be stabilized against sedimentation. However, during the layer-wise manufacturing of parts difficulties arose due to separation processes or deficient flow properties. Stereolithography as an optical forming process for the production of high quality parts requires specific optical properties of the raw material. On this account slurry systems with improved optical properties (matching of the refractive index of organic components and ceramic powder) are developed which allow the manufacturing of parts with the highest possible resolution and surface quality (minimal wall thickness of 100 µm). Due to the modified organic fraction the slurries show thixotropic flow behavior. Thereby long-time stability against sedimentation is achieved. Besides the slurry development an adaptation of the overall process chain, including additive manufacturing of parts, thermal debinding of green bodies and final sintering was necessary. Additionally, with this slurry system the author could establish a time efficient debinding process (dental crown in < 3 h)
Mouse Plasminogen Has Oxidized Phosphatidylcholine Adducts That Are Not Metabolized by Lipoprotein-Associated Phospholipase A2 under Basal Conditions
No full textWe previously showed that plasminogen (Plg) isolated from the plasma of normal human subjects contains 1–2 moles of oxidized phosphatidylcholine (oxPtdPC) adducts/mole of protein. Moreover, we suggested that these species are generated at the hepatic site and speculated that they may play a role in the reported cardiovascular pathogenicity of Plg. We aimed to determine whether mouse Plg also harbors linked oxPtdPCs and whether these molecules are metabolized by lipoprotein-associated phospholipase A2/PAF acetylhydrolase (Lp-PLA2/PAF-AH), an enzyme specific for hydrolysis of oxPtdPCs. We determined the total concentration of Plg in plasma samples from control (WT) and Lp-PLA2-deficient (KO) mice, we isolated Plg, and assessed its content of oxPtdPCs by immunoblot analyses. We also evaluated whether human recombinant Lp-PLA2 metabolized Plg-linked oxPtdPCs in vivo and in vitro. WT and KO mice expressed comparable levels (14.4–15.8 mg/dL) of plasma Plg, as determined by ELISA. We observed no differences in the content of oxPtdPC in Plg isolated from the two mouse strains and in parallel no changes in oxPtdPC content in mouse Plg following incubation with pure recombinant Lp-PLA2. Plg from mouse plasma contains oxPtdPC adducts that are not affected by the action of Lp-PLA2, suggesting that linkage to Plg protects oxPtdPCs from metabolism during their transport in the plasma. This modification may have important physio-pathological implications related to the function of Plg, oxPtdPCs, or both
Towards Interactive Indoor Thermal Comfort Simulation
No full textThe paper addresses the current state of the development of a computational steering environment (CSE) for interactive indoor thermal comfort simulation by utilizing high-performance supercomputing facilities. The CSE consists of a parallel CFD kernel, a fast spacetree-based 3D mesh generator and an integrated virtual reality-based visualization engine. The numerical method is based on a hybrid thermal lattice Boltzmann (LB) method with extensions for large eddy simulations of turbulent convective flows. We use a multiple-relaxation-time LB scheme for solving the mass and momentum equations numerically and a finite difference scheme for the heat equation. The CSE allows for modifying both the geometric model and the boundary conditions during runtime with immediate visualization of changes in the results. The application is demonstrated by two industrial applications with complex geometries, turbulent natural convection in the separator room of a ferry boat and turbulent convection in a trains passenger carriage. We currently enhance our model using a radiosity method with a fast spacetree-based visibility check and integrate a new local thermal comfort model developed by our partners
Sharpness of the Berezinskii-Kosterlitz-Thouless transition in ultrathin NbN films
No full textWe present a comprehensive investigation of the
Berezinskii-Kosterlitz-Thouless (BKT) transition in ultrathin strongly
disordered NbN films. Measurements of resistance, current-voltage
characteristics and kinetic inductance on the very same device reveal a
consistent picture of a sharp unbinding transition of vortex-antivortex pairs
that fit standard renormalization group theory without extra assumptions in
terms of inhomogeneity. Our experiments demonstrate that the previously
observed broadening of the transition is not an intrinsic feature of strongly
disordered superconductors and provide a clean starting point for the study of
dynamical effects at the BKT transition.Comment: Resubmitted, Main: 6 pages, 4 figures; Supplement: 8 pages, 13
figures, material and author adde
