Preparation of Silicon Carbide/Aluminum Nitride Ceramics Using Organometallic Precursors

Solid solutions of 2H -SiC/AlN can be prepared at temperatures less than 1600°C by rapid pyrolysis ("hot drop") of mixtures of [(Me₃Si)_0.80((CH₂=CH)MeSi)_1.0(MeHSi)_0.35] _n (VPS) or [MeHSiCH₂] _n (MPCS) with [R₂AlNH₂]₃, where R=Et, i -Bu or simply by slow pyrolysis of the precursor mixture in the case of [Et₂AlNH₂]₃. In contrast, slow pyrolysis of mixtures of VPS or MPCS with [ i -Bu₂AlNH₂]₃ yields a composite of 2 H -AlN and 3 C -SiC at 1600°C, which transforms into a single 2 H -SiC/AlN solid solution on heating to 2000°C. The influences of the nature of the precursor and processing conditions on the structure, composition, and purity of the SiC/AlN materials are discussed.     

Impacts of new technologies on media usage and social behaviour in domestic environments

Technological infrastructure at home is changing continuously and is becoming increasingly interconnected. Media devices, including the TV set, provide access to the Internet and offer manifold opportunities to consume media on demand. Additionally, personal devices, such as smartphones, also enable flexible consumption and sharing of media. Questions about how these technologies change the user's media usage and how these changes affect the social structure of a household, however, remain largely unanswered. In order to gain insight into the adoption of new technologies into daily routines, we explored these changes in respect of people's media usage in a qualitative long-term Living Lab study. We will present findings regarding personal routines, flexible integration of new devices into existing practices, influences on households as social systems and related issues in device access and collective use. We will highlight potentials and conflicts regarding device shifts and roles; restrictions in device access; social influences in the living room; and individual changes in media consumption.     

Isolation of Decidual Macrophages and Hofbauer Cells from Term Placenta—Comparison of the Expression of CD163 and CD80

(1) Background: Placental immune cells are playing a very important role in a successful placentation and the prevention of pregnancy complications. Macrophages dominate in number and relevance in the maternal and the fetal part of the placenta. The evidence on the polarization state of fetal and maternal macrophages involved in both, healthy and pregnancy-associated diseases, is limited. There is no representative isolation method for the direct comparison of maternal and fetal macrophages so far. (2) Material and Methods: For the isolation of decidual macrophages and Hofbauer cells from term placenta, fresh tissue was mechanically dissected and digested with trypsin and collagenase A. Afterwards cell enrichment was increased by a Percoll gradient. CD68 is represented as pan-macrophage marker, the surface markers CD80 and CD163 were further investigated. (3) Results: The established method revealed a high cell yield and purity of the isolated macrophages and enabled the comparison between decidual macrophages and Hofbauer cells. No significant difference was observed in the percentage of single CD163⁺ cells in the distinct macrophage populations, by using FACS and immunofluorescence staining. A slight increase of CD80⁺ cells could be found in the decidual macrophages. Considering the percentage of CD80⁺CD163⁻ and CD80⁻CD163⁺ cells we could not find differences. Interestingly we found an increased number of double positive cells (CD80⁺CD163⁺) in the decidual macrophage population in comparison to Hofbauer cells. (4) Conclusion: In this study we demonstrate that our established isolation method enables the investigation of decidual macrophages and Hofbauer cells in the placenta. It represents a promising method for direct cell comparison, enzyme independently, and unaffected by magnetic beads, to understand the functional subsets of placental macrophages and to identify therapeutic targets of pregnancy associated diseases.     

Towards reproducibility in recommender-systems research

Numerous recommendation approaches are in use today. However, comparing their effectiveness is a challenging task because evaluation results are rarely reproducible. In this article, we examine the challenge of reproducibility in recommender-system research. We conduct experiments using Plista’s news recommender system, and Docear’s research-paper recommender system. The experiments show that there are large discrepancies in the effectiveness of identical recommendation approaches in only slightly different scenarios, as well as large discrepancies for slightly different approaches in identical scenarios. For example, in one news-recommendation scenario, the performance of a content-based filtering approach was twice as high as the second-best approach, while in another scenario the same content-based filtering approach was the worst performing approach. We found several determinants that may contribute to the large discrepancies observed in recommendation effectiveness. Determinants we examined include user characteristics (gender and age), datasets, weighting schemes, the time at which recommendations were shown, and user-model size. Some of the determinants have interdependencies. For instance, the optimal size of an algorithms’ user model depended on users’ age. Since minor variations in approaches and scenarios can lead to significant changes in a recommendation approach’s performance, ensuring reproducibility of experimental results is difficult. We discuss these findings and conclude that to ensure reproducibility, the recommender-system community needs to (1) survey other research fields and learn from them, (2) find a common understanding of reproducibility, (3) identify and understand the determinants that affect reproducibility, (4) conduct more comprehensive experiments, (5) modernize publication practices, (6) foster the development and use of recommendation frameworks, and (7) establish best-practice guidelines for recommender-systems research.     

Nature and the Nazi Diet 1

This article investigates the role of natural foods and farming in Nazi Germany. Why did the state encourage Germans to eat and farm more naturally? What did “natural” mean in the context of this genocidal regime? By what means were Germans encouraged to take up these practices and to what degree did they do so? This article explores these questions by tracing the assimilation of natural foods and farming to the regime's racial, political, and economic goals. Eating more naturally, Nazi leaders believed, would promote racial health, boost physical performance, and maximize the efficient use of resources, all qualities needed to fight and win the coming war. Natural foods and farming, in short, belonged to the biopolitics of fascist modernity. The article develops this claim in two sections, one on efforts to make German diets more natural, the other on an early form of organic farming known as biodynamics. The conclusion considers the implications of these findings for food historians more generally.     

Optimizing water tanks in water distribution systems by combining network reduction,mathematical optimization and hydraulic simulation

In the last two decades, water consumption in Germany has been decreasing, which causes the water tanks and pipes in water distribution systems to work inefficiently. This paper proposes a method that supports the planning process for tanks in water distribution systems. The method uses a combination of network reduction, mathematical optimization and hydraulic simulation. The mathematical optimization model is a non-convex Mixed Integer Quadratically Constrained Program (MIQCP) that is solved by a piecewise linearization. As this may lead to many binary variables and therefore high computing times, the size of the water distribution system model is reduced before building the optimization model. After applying several network reduction techniques and using a piecewise approximation of the original model, there may be some hydraulic differences between the original network model and the reduced network model. To make sure that the solution obtained in the optimization process is feasible in the original water distribution system model, the solution is verified by a hydraulic simulation. If the solution is not feasible, the reduced model has to be modified and solved again until the hydraulic simulation verifies a solution as feasible. In this paper, each of these processes is described and the results indicate the usefulness of each of them.     

Multiscale analysis of the urbanization pattern of the Phoenix metropolitan landscape of USA: Time,space and thematic resolution

Investigating the ecological consequences of urbanization require knowledge of land-cover dynamics. Quantification of land-use/land-cover change in Phoenix, Arizona during the period of 1985–2005 using landscape metrics computed from Landsat-derived maps revealed temporal patterns of landscape composition and configuration. With accelerated urbanization the landscape as a whole became more fragmented ecologically and more complex compositionally and geometrically. However, the majority of individual patches became more compact in shape. Urban land covers, especially xeric residential, increased substantially and the desert decreased by 20%. Spatial and thematic resolution of data was shown to have large effects on the analysis of land-cover pattern. Our results, while agreeing in general with previously reported scaling relations with respect to changing spatial grain and extent, showed that scaling relations are also robust and consistent across thematic resolutions and time periods. Some metrics behaved unpredictably and some exhibited scale-free behavior. Compositional metrics, such as patch density, diversity, evenness, and largest patch index, were well correlated with vegetative cover, its spatial variation, and population density. Many of these correlations exhibited hump-shaped patterns with respect to increasing grain size, indicating a characteristic scale at approximately 500–1000 m. By simultaneously manipulating spatial and thematic resolutions, the importance of the Modifiable Area Unit Problem in relating landscape patterns to vegetation and socio-economic variables was also demonstrated. Additionally, highly variable desert vegetation due to precipitation variability poses a challenge for accurately quantifying urbanization pattern in arid environments. Choosing appropriate spatial, temporal and thematic resolutions is essential in meeting this challenge.     

Authentication analysis of caffeine-containing foods via elemental analysis combustion/pyrolysis isotope ratio mass spectrometry (EA-C/P-IRMS)

The δ¹³CVPDB and δ¹⁸OVSMOW values of caffeine isolated from commercial caffeine-containing foods were determined by isotope ratio mass spectrometry (IRMS) using elemental analysis (EA) in the 'combustion' (C) and 'pyrolysis' (P) modes (EA-C/P-IRMS), respectively. In total, 69 samples (32 guarana products, 20 teas, 12 coffee products, and 5 maté teas) were analyzed together with three references of synthetic caffeine. Validation was done by excluding isotope discrimination in the course of sample preparation and determining linear dynamic ranges for EA-P-IRMS measurements. In total, five samples (one caffeine-containing soft drink and four guarana products) under study contained synthetic caffeine.     

Impact of the Nanoscale Gap Morphology on the Plasmon Coupling in Asymmetric Nanoparticle Dimer Antennas

Coupling of plasmon resonances in metallic gap antennas is of interest for a wide range of applications due to the highly localized strong electric fields supported by these structures, and their high sensitivity to alterations of their structure, geometry, and environment. Morphological alterations of asymmetric nanoparticle dimer antennas with (sub)‐nanometer size gaps are assigned to changes of their optical response in correlative dark‐field spectroscopy and high‐resolution transmission electron microscopy (HR‐TEM) investigations. This multimodal approach to investigate individual dimer structures clearly demonstrates that the coupling of the plasmon modes, in addition to well‐known parameters such as the particle geometry and the gap size, is also affected by the relative alignment of both nanoparticles. The investigations corroborate that the alignment of the gap forming facets, and with that the gap area, is crucial for their scattering properties. The impact of a flat versus a rounded gap structure on the optical properties of equivalent dimers becomes stronger with decreasing gap size. These results hint at a higher confinement of the electric field in the gap and possibly a different onset of quantum transport effects for flat and rounded gap antennas in corresponding structures for very narrow gaps.     

Discovery and Pharmacophore Mapping of a Low-Nanomolar Inhibitor of P. falciparum Growth

The treatment of malaria, the most common parasitic disease worldwide and the third deadliest infection after HIV and tuberculosis, is currently compromised by the dramatic increase and diffusion of drug resistance among the various species of Plasmodium, especially P. falciparum (Pf). In this view, the development of new antiplasmodial agents that are able to act via innovative mechanisms of action, is crucial to ensure efficacious antimalarial treatments. In one of our previous communications, we described a novel class of compounds endowed with high antiplasmodial activity, characterized by a pharmacophore never described before as antiplasmodial and identified by their 4,4’-oxybisbenzoyl amide cores. Here, through a detailed structure-activity relationship (SAR) study, we thoroughly investigated the chemical features of the reported scaffolds and successfully built a novel antiplasmodial agent active on both chloroquine (CQ)-sensitive and CQ-resistant Pf strains in the low nanomolar range, without displaying cross-resistance. Moreover, we conducted an in silico pharmacophore mapping.