Synthesis of polyvinylpyrrolidone/silver nanoparticles hybrid latex in non-aqueous miniemulsion at high temperature

Since emulsions tend to become unstable with increasing temperature, reactions in emulsions are usually not performed at high temperatures. We show that non-aqueous inverse miniemulsions are relatively stable at temperatures higher than 150 °C. As an example of this remarkable stability, composite particles consisting of Ag nanoparticles and a polymer were synthesized via the polyol process in the monomer droplets to reduce silver ions to silver followed by the polymerization of the monomer. Silver nanoparticles were hence embedded in polyvinylpyrrolidone matrix particles. We showed here that non-aqueous miniemulsion nanodroplets are suitable loci for reactions performed at high temperature.     

Surface Chemical Characterization of Ceramic Materials: Adsorption and Degradation of 3,6,9-Trioxadecanoic Acid on Nano-ZrO2

This paper deals with the specific interaction of the dispersant 3,6,9-trioxadecanoic acid (TODA) with nano-ZrO₂ surfaces. Special interest was directed towards degradation behavior of the adsorbates and its influence on dispersant capabilities of TODA regarding stabilization of ethanolic nano-ZrO₂ suspensions. ZrO₂ adsorption sites and the adsorbates formed are examined by diffuse reflectance infrared Fourier transform spectroscopy, thermal analysis, ¹H-, and ¹³C-cross polarization magic angle spinning solid-state nuclear magnetic resonance spectroscopy. ¹H as well as ¹³C-chemical shifts and the configurations of the corresponding adsorbed TODA species on zirconia sites are predicted by means of density functional theory quantum chemical calculations for supporting the interpretation of the experimental spectral data obtained. This work shows that combination of analytical and theoretical methods is an effective approach characterizing surface chemical properties of ceramic materials, determining sorption properties of organic process additives, investigating correspondent elementary and degradation reactions as well as clarifying cause-effect relationships in ceramic processes.     

Wärmeleitfähigkeit eines Gemisches von Metallkugeln und ÖI

Zusammenfassung Die W?rmeleitf?higkeit von Gemischen aus festen und flüssigen Stoffen in Abh?ngigkeit von der W?rmeleitf?higkeit der Füllstoffe wird bestimmt Diese Arbeit wurde ausgeführt unter Leitung von Prof. Dr.Hase, dem ich für die Anregung zu der Arbeit und seine stete Hilfsbereitschaft herzlich danke.     

Low temperature fabrication of magnesium phosphate cement scaffolds by 3D powder printing

Synthetic bone replacement materials are of great interest because they offer certain advantages compared with organic bone grafts. Biodegradability and preoperative manufacturing of patient specific implants are further desirable features in various clinical situations. Both can be realised by 3D powder printing. In this study, we introduce powder-printed magnesium ammonium phosphate (struvite) structures, accompanied by a neutral setting reaction by printing farringtonite (Mg₃(PO₄)₂) powder with ammonium phosphate solution as binder. Suitable powders were obtained after sintering at 1100°C for 5 h following 20–40 min dry grinding in a ball mill. Depending on the post-treatment of the samples, compressive strengths were found to be in the range 2–7 MPa. Cytocompatibility was demonstrated in vitro using the human osteoblastic cell line MG63.     

No security: A meta-analysis and review of job insecurity and its consequences.

Meta-analytic techniques were used to estimate how job insecurity relates to its postulated outcomes. Consistent with the conceptual framework, the results indicate that job insecurity has detrimental consequences for employees' job attitudes, organizational attitudes, health, and, to some extent, their behavioral relationship with the organization. Moderator analyses suggest that these relationships may be underestimated in studies relying on single-item measures of job insecurity and that the behavioral consequences of insecurity are more detrimental among manual, as compared with nonmanual, workers. Recommendations made for future research include utilization of multidimensional measures, consideration of a broader spectrum of outcomes and moderators, and use of longitudinal designs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Friction and ablation measurements in a round bore railgun

Detailed experiments were performed in order to determine electrode ablation and friction effects in a round-bore railgun. An accelerating model was developed which includes electrode-ablation effects, the viscous arc drag, and the mechanical friction of the projectile. In addition, a novel nonlinear electrode-ablation model was found to describe the experimental data very well. A model for the mechanical friction force between the projectile and bore wall was applied to the equation of motion. The position/time data of the projectile acceleration could be adjusted with quite reasonable friction effects. Theoretical and experimental results show that the `ideal' projectile velocity is decreased by about 28%: 15% due to electrode ablation, 9% due to mechanical friction, and about 4% due to viscous arc drag     

Aryl Bis‐Sulfonamide Inhibitors of IspF from Arabidopsis thaliana and Plasmodium falciparum

2‐Methylerythritol 2,4‐cyclodiphosphate synthase (IspF) is an essential enzyme for the biosynthesis of isoprenoid precursors in plants and many human pathogens. The protein is an attractive target for the development of anti‐infectives and herbicides. Using a photometric assay, a screen of 40 000 compounds on IspF from Arabidopsis thaliana afforded symmetrical aryl bis‐sulfonamides that inhibit IspF from A. thaliana (AtIspF) and Plasmodium falciparum (PfIspF) with IC₅₀ values in the micromolar range. The ortho‐bis‐sulfonamide structural motif is essential for inhibitory activity. The best derivatives obtained by parallel synthesis showed IC₅₀ values of 1.4 μm against PfIspF and 240 nm against AtIspF. Substantial herbicidal activity was observed at a dose of 2 kg ha^?1. Molecular modeling studies served as the basis for an in silico search targeted at the discovery of novel, non‐symmetrical sulfonamide IspF inhibitors. The designed compounds were found to exhibit inhibitory activities in the double‐digit micromolar IC₅₀ range.