M?bius Strip Segmented into Flat Trapezoids: Design-Build Project by the Departments of Architecture and Mathematics of the Technische Universit?t Darmstadt

The M?bius strip trade fair stand was designed and built by students of the Faculty of Architecture of Darmstadt Technical University in collaboration with students of the Faculty of Mathematics. The project focused on two main issues: to introduce computer-driven parametric design and production strategies, techniques and technologies into architectural education, and to build and operate the final result. This required knowledge of different software packages and readiness to become familiar quickly with unknown data formats, flexibility in the time schedule and disposition to transport the material to the machinery. It introduced students to the possibilities of designing with parametric modeling software and familiarized them with the initial difficulties and ample payback in actual production.     

Modular Functionalization of Electrodes by Cross‐Coupling Reactions at Their Surfaces

Due to the increasing importance of modified electrodes for many applications in nanotechnology, including molecular electronics, bioelectronics, and sensors, there is a need to find ways to chemically attach suitable molecular films onto the electrodes. Combining the electroreduction of aryl diazonium salts with the Sonogashira cross‐coupling reaction, a new modular technique to modify electrodes is presented. The new technique allows a wide range of functional groups to be introduced onto electrode surfaces with high surface coverage by the functional subunit. Various organic subunits, including redox chromophores, are successfully attached to platinum electrodes. The corresponding films are characterized using cyclic voltammetry, X‐ray photoelectron spectroscopy, atomic force microscopy, and contact‐angle measurements. The electroreduction of diazonium salts is successfully achieved on a broad variety of conducting and semiconducting surfaces, which shows that the technique is applicable to a broad variety of substrates.     

Lineare versus sprungfixe Erfolgsbeteiligung

Zusammenfassung Der vorliegende Beitrag diskutiert die Gestaltung optimaler Anreizsysteme für zwei Typen von Erfolgsbeteiligungen: die lineare und die sprungfixe Belohnungsfunktion. Im Gegensatz zu der üblichen Annahme der Principal-Agent-Theorie einer einmaligen Realisation eines Projekts betrachten wir die spezielle Situation, daß eine mehrmalige Wiederholung eines bestimmten Projekttyps in gleicher Form möglich ist. Es wird gezeigt, daß für den Fall der Risikoversion des Entscheidungsträgers und Risikoneutralität der Instanz die sprungfixe Belohnungsfunktion gegenüber der linearen Belohnungsfunktion von Vorteil sein kann.Wir danken einem anonymen Gutachter für wertvolle Verbesserungsvorschläge.     

Development of a hyphenated microanalytical system for the investigation of leaching kinetics of heavy metals in environmental samples

A fast and convenient method for on-line monitoring of the extraction of heavy metals from solid (environmental) matrixes was developed. By the incorporation of microcartridges filled with dried and pulverized solid samples into the conduits of a flow system and appropriate selection of the liquid flowing through the cartridge, information about the degree of leaching and in particular of the kinetics of the leaching process are obtained. The method was optimized for determination of different metals of environmental concern using in-line detection by FAAS and ICPMS.     

Behavioral Subtyping Relations for Active Objects

In this paper we investigate the object-oriented notion of subtyping in the context of behavioral formalisms. Behavioral formalisms are used to describe the dynamic behavior of active objects, viz. the protocols of interaction that active objects have to obey.Subtyping in OO-formalisms is closely related to the concept of inheritance. The central issue in the choice of subtyping relations among classes is the principle of substitutability: an instance of the subtype should be usable wherever an instance of the supertype was expected. Depending on the interpretation of usable, we obtain a variety of subtyping relations: stronger relations, allowing sharing of subtype instances among different clients, and weaker relations, restricting the possibilities of interference of different clients on the subtype instance. The subtyping relations are taxonomically ordered in a hierarchy. Substitutability is formalized via testing scenarios, which provide alternative characterizations for the subtyping relations.     

Working models of attachment and reactions to different forms of caregiving from romantic partners.

Inspired by attachment theory, the authors tested a series of theoretically derived predictions about connections between attachment working models (attachment to one's parents assessed by the Adult Attachment Interview; M. Main & R. Goldwyn, 1994) and the effectiveness of specific types of caregiving spontaneously displayed by dating partners during a stressful conflict-resolution discussion. Each partner first completed the Adult Attachment Interview. One week later, each couple was videotaped while they tried to resolve a current problem in their relationship. Trained observers then rated each interaction for the degree to which (a) emotional, instrumental, and physical caregiving behaviors were displayed; (b) care recipients appeared calmed by their partners' caregiving attempts; and (c) each partner appeared distressed during the discussion. Individuals who had more secure representations of their parents were rated as being more calmed if/when their partners provided greater emotional care, especially if they were rated as more distressed. Conversely, individuals who had more insecure (dismissive) representations of their parents reacted more favorably to instrumental caregiving behaviors from their partners, especially if they were more distressed. The broader theoretical implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In situ Characterization of SiO2 Nanoparticle Biointeractions Using BrightSilica

By adding a gold core to silica nanoparticles (BrightSilica), silica‐like nanoparticles are generated that, unlike unmodified silica nanoparticles, provide three types of complementary information to investigate the silica nano‐biointeraction inside eukaryotic cells in situ. Firstly, organic molecules in proximity of and penetrating into the silica shell in live cells are monitored by surface‐enhanced Raman scattering (SERS). The SERS data show interaction of the hybrid silica particles with tyrosine, cysteine and phenylalanine side chains of adsorbed proteins. Composition of the biomolecular corona of BrightSilica nanoparticles differs in fibroblast and macrophage cells. Secondly, quantification of the BrightSilica nanoparticles using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) micromapping indicates a different interaction of silica nanoparticles compared to gold nanoparticles under the same experimental conditions. Thirdly, the metal cores allow the investigation of particle distribution and interaction in the cellular ultrastructure by cryo nanoscale X‐ray tomography (cryo‐XT). In 3D reconstructions the assumption is confirmed that BrightSilica nanoparticles enter cells by an endocytotic mechanism. The high SERS intensities are explained by the beneficial plasmonic properties due to agglomeration of BrightSilica. The results have implications for the development of multi‐modal qualitative and quantitative characterization in comparative nanotoxicology and bionanotechnology.     

Electrical Conduction Behavior of La1+xSr1−xGa3O7–δ Melilite-Type Ceramics

Ceramics of the melilite-type compound La_{1+ x} Sr_{1− x} Ga₃O_7−δ were prepared by conventional ceramic processing. Samples prepared represented the entire homogeneity region of the phase (i.e., x =−0.15 to 0.60). Electrochemical characterization under variable temperature and atmospheric conditions in the vicinity of air entailed four-point direct-current conductivity measurements and electromotive force measurements. La_{1+ x} Sr_{1− x} Ga₃O_7−δ samples exhibited a p -type behavior with generally increased conductivity with increased substitution of lanthanum for strontium, which reached a saturation value of ∼10⁻¹ S·cm⁻¹ at 950°C.     

Design and Fabrication of Transparent and Gas‐Tight Optical Windows in Low‐Temperature Co‐Fired Ceramics

Low‐temperature co‐fired ceramics (LTCC) enable the fabrication of microfluidic elements such as channels and embedded cavities in electrical devices. Hence, LTCC facilitate the realization of complex and integrated microfluidic devices. Examples can be applied in many areas like reaction chambers for synthesis of chemical compounds. However, for many applications it is necessary to have an optically transparent interface to the surroundings. The integration of optical windows in LTCC opens up a wide field of new and innovative applications such as the observation of chemiluminescent reactions. These chemical reactions emit electromagnetic radiation and thus offer a method for noninvasive detection. Thin glasses (≤500 μm) were bonded by thermocompression onto a LTCC substrate. As the bonding agent, a glass frit paste was used. Borosilicate glasses, fused silica as well as silicon were successfully bonded onto LTCC. To join materials with a large coefficient of thermal expansion mismatch (i.e., fused silica and LTCC), it is necessary to limit the heat input to the bond interface. Therefore, a heating structure was integrated into the LTCC substrate beneath the bond interface. This bonding process provides a gas‐tight optical port with a high bond strength.