Materials,effects and components for tunable micro‐optics

An overview of recent activities in the area of tunable micro‐optical components is given. These include polymer‐based deformable mirrors for adaptive optics, tunable microlenses and arrays using fluids and membranes, pneumatically actuated scanning micromirrors and tunable Bragg filters and mirrors using swelling polymers. For each device, the structure, essential fabrication technology and optical characteristics, as well as a discussion of application areas are presented. Copyright © 2007 Institute of Electrical Engineers of Japan© 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Cyclopropyl Building Blocks for Organic Synthesis, 131. Palladium‐Catalyzed Bicyclization with Carbonyl Insertion of Alkenyl‐Tethered Propargyl Carbonates Towards a Scalable Synthesis of Various 2‐(Bicyclo[3.1.0]hex‐1‐yl)acrylates

The Pd‐catalyzed 5‐exo‐trig‐3‐exo‐trig cascade cyclization of 1,6‐enynes with a propargyl carbonate terminus offers the shortest synthetic route to variously substituted 2‐(bicyclo[3.1.0]hex‐1‐yl)acrylates, a novel class of prospective monomers for low‐shrinkage polymers. To apply this reaction to large‐scale preparations of the said bicyclic acrylates, a flexible Pd catalyst system with tunable reactivity has been developed. The dependence of the product and diastereomer distribution on both the reaction conditions, including the type of palladium catalyst used, and on the nature of the substrate has been investigated. A variety of methyl 2‐(bicyclo[3.1.0]hex‐1‐yl)acrylates and parent carboxylic acids as well as some of their derivatives of potential interest towards a technical application were prepared on a multigram scale. A general large‐scale synthesis of the cyclization precursors bearing one or two carbonyl groups in the tether is also disclosed.     

Teilversagen eines Rohwaschkohlebunkers – Ursachen und Schlußfolgerungen

Partial Collapse of a Raw Coal Bunker The sidewall of a raw coal bunker fell down after having been in use for 30 years. The collapse has given rise to the survey of similar structures on the basis of the discovered causes. Due to highly mechanisised methods of mining, the soil mechanical properties of mined coal have changed significantly. Furthermore, extended knowledge of the theory of soil pressure is now available. As a result, at least increased active soil pressure has to be considered when rigid structures, as given, are planned.     

Design of Mechanical Viscous Dampers for Stay Cables

External dampers have been utilized in a number of cable-stayed bridges to suppress transverse cable vibrations. However, simple and accurate damper design recommendations that concurrently consider all important cable parameters are lacking. Previous efforts have been based on the idealization of cables as taut strings. In this paper, the governing differential equation for vibration of cables containing a viscous damper was first converted to a complex eigenvalue problem containing nondimensional cable parameters. Then, a parametric study was conducted involving repeated solutions of the eigenvalue problem for a wide range of nondimensional parameters. Based on the results of the parametric study, the effects of dampers on first mode vibration frequencies and first mode cable damping ratios were presented in nondimensional format. It is shown that for the range of parameters involved in most stay cables, the influence of cable sag is insignificant, whereas the cable bending stiffness can have a significant influence on the resulting cable damping ratios. Simplified nondimensional relationships are proposed for calculating damper-induced changes in the first mode cable damping ratios. Results of laboratory tests on a scaled model cable are compared with the estimated values using the formulation presented. Finally, example problems are presented for comparison with other relationships, and for the design of mechanical viscous dampers for suppression of cable vibrations including rain-wind induced vibrations.     

A simple and powerful flow cytometric method for the simultaneous determination of multiple parameters at G protein-coupled receptor subtypes

The quantification of pharmacological parameters at G protein-coupled receptors (GPCRs) is indispensable in drug research but costly and time-consuming when conventional methods are sequentially applied. With neuropeptide Y (NPY) Y(1), Y(2), and Y(5) receptors as model systems, a homogenous flow cytometric method for the simultaneous determination of the affinity, selectivity, and activity of GPCR ligands was developed. Mixtures of cells expressing the receptors of interest and cyanine-labeled NPY as a universal fluorescent Y(1), Y(2), and Y(5) receptor agonist were used. Calcium mobilization was measured in different channels with the aid of fluo-4 and fura red. A combination of dye-loaded HEL-Y(1) and CHO-Y(2)-Galpha(qi5) cells with unloaded HEC-1B-Y(5) cells allowed the simultaneous determination of Y(1), Y(2), and Y(5) receptor selectivity preceded by the Y(1) and Y(2) receptor-mediated response with one and the same sample. The data are in good agreement with those determined by radioligand binding and spectrofluorimetry. The convenient, robust, and inexpensive multiparametric procedure offers a broad range of applications in the pharmacological characterization of GPCR ligands.     

Modeling the bending vibration of cross-laminated timber beams

Cross-laminated timber (CLT) is an economical construction material combining good structural properties and environmental advantages. Due to the layered geometry and the associated internal stress boundary conditions, modelling its dynamic behavior is complex. However, accurate vibration level estimations are necessary to estimate the sound insulation performance of CLT constructions. This paper outlines a method to determine the relevant elastic constants and the appropriate equations of motion to predict the vibration of beams cut from a three-ply CLT plate. Modal analysis performed on strips cut along the two principal directions provides insight in the material’s dynamics. The bending mode frequencies are determined experimentally by analyzing the sweep response spectrum using the linear prediction method. In a second step, analytical beam vibration models of increasing complexity are fitted to the measurements using a genetic optimization algorithm. Thin beam theory—the simplest model—does not predict the bending modes with sufficient accuracy. Depending on the strip direction, the bending vibrations can be modeled using Timoshenko’s theory for thick beams, or by a model for three layer sandwich beams respectively. The results show that taking the beam geometry into account is as important as estimating the orthotropic material constants to model the bending modes properly.     

Role of architectural space in blast-resistant buildings

The design of all spatial scales in a manufactured environment is part of the architectural skills and knowledge. Therefore, an architectural design should be drafted to reduce the vulner- ability of humans and buildings against unexpected events, such as terrorist attacks and bombardments. Human casualties and equipment destruction inside the buildings could be prevented by designing a suitable architectural space. This study addresses the absence of a codified and detailed criterion to evaluate architectural spaces and their design. Hence, all proposed indices for architectural spaces have been extracted using the ideas of experts in the field of architecture and explosives. Questionnaires were presented to 25 experts to weigh the effective indices using the analytic hierarchy process method. The human-oriented (ergonomic) characteristics of the building space is found to be the most important factor in facilitating crisis management, followed by the location of critical spaces.     

Synthesis of Chiral 2‐Hydroxy‐1‐methylpropanoates by Rhodium‐Catalyzed Stereoselective Hydrogenation of α‐(Hydroxymethyl)‐acrylate Derivatives

The synthesis of chiral 3‐hydroxy‐2‐methylpropanoic acid esters (e.g., “Roche ester” 3a ) based on the rhodium‐catalyzed stereoselective hydrogenation of Baylis–Hillman reaction products was investigated. Full conversions and enantioselectivities of up to 99% at a substrate/catalyst ratio of up to 500/1 were achieved by application of bisphospholanes of the catASium M series as ancillary ligands. An interesting kinetic resolution was observed by the diastereoselective hydroxy‐directed hydrogenation of related racemic β‐branched precursors affording mainly anti‐isomers with up to 96%ee.     

Perylene-labeled silica nanoparticles: synthesis and characterization of three novel silica nanoparticle species for live-cell imaging

The increasing exposure of humans to nanoscaled particles requires well-defined systems that enable the investigation of the toxicity of nanoparticles on the cellular level. To facilitate this, surface-labeled silica nanoparticles, nanoparticles with a labeled core and a silica shell, and a labeled nanoparticle network-all designed for live-cell imaging-are synthesized. The nanoparticles are functionalized with perylene derivatives. For this purpose, two different perylene species containing one or two reactive silica functionalities are prepared. The nanoparticles are studied by transmission electron microscopy, widefield and confocal fluorescence microscopy, as well as by fluorescence spectroscopy in combination with fluorescence anisotropy, in order to characterize the size and morphology of the nanoparticles and to prove the success and homogeneity of the labeling. Using spinning-disc confocal measurements, silica nanoparticles are demonstrated to be taken up by HeLa cells, and they are clearly detectable inside the cytoplasm of the cells.