Rattling modes and the intrinsic vibrational spectrum of beetle-type scanning tunneling microscopes

It is known that the vibrational spectra of beetle-type scanning tunneling microscopes with a total mass of approximately 3-4 g contain extrinsic 'rattling' modes in the frequency range extending from 500 to 1700 Hz that interfere with image acquisition. These modes lie below the lowest calculated eigenfrequency of the beetle and it has been suggested that they arise from the inertial sliding of the beetle between surface asperities on the raceway. In this paper we describe some cross-coupling measurements that were performed on three home-built beetle-type STMs of two different designs. We provide evidence that suggests that for beetles with total masses of 12-15 g all the modes in the rattling range are intrinsic. This provides additional support for the notion that the vibrational properties of beetle-type scanning tunneling microscopes can be improved by increasing the contact pressure between the feet of the beetle and the raceway.     

络合剂在优化纺织品湿加工整理中韵应用

新型络合剂在多种工序中的应用，可以为单道工序甚至整个生产过程节约大量成本，加速生产循环，省去部分加工步骤，同时还提高了不稳定配方的生产可靠性。极简化的操作水平也可以节约大量能源。现代技术和设计应将络合剂作为重要的过程控制参数，因为这关系到整个工艺的成败，     

Modeling of biocatalytic reactions: A workflow for model calibration,selection, and validation using Bayesian statistics

We present a workflow for kinetic modeling of biocatalytic reactions which combines methods from Bayesian learning and uncertainty quantification for model calibration, model selection, evaluation, and model reduction in a consistent statistical framework. Our workflow is particularly tailored to sparse data settings in which a considerable variability of the parameters remains after the models have been adapted to available data, a ubiquitous problem in many real-world applications. Our workflow is exemplified on an enzyme-catalyzed two-substrate reaction mechanism describing the symmetric carboligation of 3,5-dimethoxy-benzaldehyde to (R)-3,3′,5,5′-tetramethoxybenzoin catalyzed by benzaldehyde lyase from Pseudomonas fluorescens. Results indicate a substrate-dependent inactivation of enzyme, which is in accordance with other recent studies.     

The CENP-T C-Terminus Is Exclusively Proximal to H3.1 and not to H3.2 or H3.3

The kinetochore proteins assemble onto centromeric chromatin and regulate DNA segregation during cell division. The inner kinetochore proteins bind centromeres while most outer kinetochore proteins assemble at centromeres during mitosis, connecting the complex to microtubules. The centromere–kinetochore complex contains specific nucleosomes and nucleosomal particles. CENP-A replaces canonical H3 in centromeric nucleosomes, defining centromeric chromatin. Next to CENP-A, the CCAN multi-protein complex settles which contains CENP-T/W/S/X. These four proteins are described to form a nucleosomal particle at centromeres. We had found the CENP-T C-terminus and the CENP-S termini next to histone H3.1 but not to CENP-A, suggesting that the Constitutive Centromere-Associated Network (CCAN) bridges a CENP-A- and a H3-containing nucleosome. Here, we show by in vivo FRET that this proximity between CENP-T and H3 is specific for H3.1 but neither for the H3.1 mutants H3.1^C96A and H3.1^C110A nor for H3.2 or H3.3. We also found CENP-M next to H3.1 but not to these H3.1 mutants. Consistently, we detected CENP-M next to CENP-S. These data elucidate the local molecular neighborhood of CCAN proteins next to a H3.1-containing centromeric nucleosome. They also indicate an exclusive position of H3.1 clearly distinct from H3.2, thus documenting a local, and potentially also functional, difference between H3.1 and H3.2.     

Migration of mineral oil from printed paperboard into dry foods: survey of the German market

From the German market, 119 samples of dry food were analyzed for the migration of mineral oil. The products selected were packed in paperboard boxes and intended for storage for extended periods of time at ambient temperature. The 0.6 mg/kg limit for mineral oil saturated hydrocarbons (MOSH) derived from the WHO/JECFA evaluation was frequently exceeded by a factor of 10–100. Typically, 10–20% of the migrating mineral oil consisted of aromatic hydrocarbons (MOAH). Most samples were merely 2–3 months old and far from the end of their shelf life (usually 1–3 years). From the assumption that about 70% of the MOSH and MOAH which are eluted from GC up to the C₂₄ n-alkane (<C24) end up in the food (potential of migration), it was estimated that migration might almost triple before the products reach the end of their shelf life, reaching 31 mg/kg on average, with several samples exceeding 100 mg/kg. At the time of the analysis, products without an internal bag and with a bag of paper or polyethylene reached up to about 80% of the potential of migration (average, 30–50%). Bags of polypropylene, acrylate-coated polypropylene, PET or with an aluminum layer seemed to block migration (with one possible exception), but it was premature to reach conclusions on long-term functional barrier properties. From the comparison with <C₂₄ MOSH concentrations in unprinted recycled paperboards, it was estimated than on average about a quarter of the migrating mineral oil was from printing ink used for decorating the box.     

Controlling Electron and Hole Charge Injection in Ambipolar Organic Field‐Effect Transistors by Self‐Assembled Monolayers

Controlling contact resistance in organic field‐effect transistors (OFETs) is one of the major hurdles to achieve transistor scaling and dimensional reduction. In particular in the context of ambipolar and/or light‐emitting OFETs it is a difficult challenge to obtain efficient injection of both electrons and holes from one injecting electrode such as gold since organic semiconductors have intrinsically large band gaps resulting in significant injection barrier heights for at least one type of carrier. Here, systematic control of electron and hole contact resistance in poly(9,9‐di‐n‐octylfluorene‐alt‐benzothiadiazole) ambipolar OFETs using thiol‐based self‐assembled monolayers (SAMs) is demonstrated. In contrast to common believe, it is found that for a certain SAM the injection of both electrons and holes can be improved. This simultaneous enhancement of electron and hole injection cannot be explained by SAM‐induced work‐function modifications because the surface dipole induced by the SAM on the metal surface lowers the injection barrier only for one type of carrier, but increases it for the other. These investigations reveal that other key factors also affect contact resistance, including i) interfacial tunneling through the SAM, ii) SAM‐induced modifications of interface morphology, and iii) the interface electronic structure. Of particular importance for top‐gate OFET geometry is iv) the active polymer layer thickness that dominates the electrode/polymer contact resistance. Therefore, a consistent explanation of how SAM electrode modification is able to improve both electron and hole injection in ambipolar OFETs requires considering all mentioned factors.     

Zur Berechnung von Holz‐Beton‐Verbundträgern mit Methoden der mathematischen Optimierung

Holz‐Beton‐Verbundkonstruktionen weisen als hybride Tragwerke gegenüber reinen Holz‐ bzw. Stahlbetonkonstruktionen zahlreiche Vorteile auf. Wesentlich für die Effizienz der Hybridbauweise ist die Ausbildung der Verbundfuge. Der vorliegende Beitrag stellt ein neues Verbundelement für Straßenbrücken in Holz‐Beton‐Verbundbauweise vor, welches im Rahmen eines Forschungsprojekts an der Bauhaus‐Universität Weimar entwickelt wurde. Die rechnerische Analyse der Verbundkonstruktion erfolgt — abweichend von den im Hybridbau bisher üblichen Berechnungsmethoden — unter Anwendung von Energiemethoden und Nutzung von Algorithmen der mathematischen Optimierung. Calculation of timber‐concrete composite structures using mathematical optimization methods. Timber‐concrete composite structures have many advantages over conventional timber and re inforced concrete structures. The efficiency of such hybrid structures significantly depends on the properties of the com posite joint. This article presents a novel structural element for the joint of timber‐concrete composite bridges, which was developed as part of a research project at the Bauhaus‐Universität Weimar. In contrast to standard calculation methods, an energy method and the mathematical optimization is applied for the numerical analysis of the hybrid structure.     

DESIGN FOR RESILIENCE: RE-CONNECTING COMMUNITIES AND ENVIRONMENTS

This article stresses the importance of positive image and perception of dynamic ecological processes for the implementation and care of areas which provide ecosystem services within the city. Those in turn secure the resilience of our urban environment. Aesthetic experience with emphasis on highlighting and revealing the presence of ecological dynamics, processes and cycles can increase the acceptance and interest for sustainable goals and projects within the city. Thus, several European cities are currently implementing strategies not only to enhance the capacity of their green networks for ecological services and resilience but most importantly to enhance the acceptance and active use of such areas. They are integrating the public in an open debate about implementing new attractive ecological amenities within a green network, and also stimulating landscape architects to find ways to design important ecological processes and functions in an eye-catching and spectacular way. The natural dynamics and cycles are thus brought to the attention of the people and present an important artistic and cultural component of resilience.     

“Invisible” Silver Tracks Produced by Combining Hot‐Embossing and Inkjet Printing

Hot‐embossed features are prepared by pushing customized and standard silicon calibration gratings, known as masters, into either polystyrene or polycarbonate, which are kept above their glass transition temperatures. droplet of a silver nanoparticle ink is then dispensed over one of these as‐formed grooves using an inkjet printer. The ink fills the grooves as a consequence of capillary forces and is observed to form tracks with a uniform width. The tracks are described as ‘invisible’ on account of having widths ranging from 5 to 15 µm. Wider tracks can be produced by dispensing more droplets and tracks with different morphologies can be produced by using different masters. Several as‐prepared features are thermally treated to produce conductive silver tracks. The conductivity of the tracks is found to be ～20% that of bulk silver.