Photoegradation of indigo in dichloromethane solution

The photodegradation of indigo has been studied with emphasis on the degradation products. Ultraviolet–visible spectrometry, high performance liquid chromatography and direct temperature-resolved mass spectrometry were employed for the characterisation of aged samples. Indigo, isatin, isatoic anhydride, anthranilic acid and indirubin were detected, together with other unidentified compounds. A new degradation product, tryptanthrin, was identified by both high performance liquid chromatography and mass spectrometry techniques, and two other possible degradation products have also been suggested. The degradation of synthetic and natural indigo has been compared and an explanation for the higher rate of degradation of natural indigo proposed.     

Kinetics and driving forces of abnormal grain growth in thin Cu films

The abnormal growth of individual (1 0 0) oriented grains is monitored by the in situ electron backscatter diffraction technique for more than 24 h at three different annealing temperatures (90 °C, 104 °C and 118 °C) in 1-5 μm thick Cu films on polyimide substrates. The (1 0 0) grain growth velocity increases with higher film thickness and annealing temperature, as suggested by an earlier model by Thompson and Carel. As a result, the final (1 0 0) texture fraction becomes more dominant for higher annealing temperatures and larger film thicknesses. The Thompson-Carel model, however, predicts that the (1 1 1) grains will preferably grow at temperatures up to 118 °C. Our calculations of the driving forces revealed that in addition to minimization of the strain energy (due to the thermal mismatch between film and substrate) and of the surface energy, the energy stored in the dislocations plays a decisive role in grain growth. Our observations can be understood by the notion that initially available (1 0 0) grain nuclei start to grow very rapidly, due to dislocation annihilation, and thus “overrun” the (1 1 1) grains in size.     

Design and control strategies for SMA actuators in a feed axis for precision machine tools

In a current project, the Chair of Production Systems (LPS) is examining the use of standardized shape memory alloy (SMA) actuators in the feed axis of a small machine tool. These machines are used to manufacture small work pieces with high precision. Therefore, the actuators must be qualified to handle movements in the micrometer range. To achieve this goal, different design elements for the actuators are considered, as well as different measures to control the actuator. In the scope of this paper, binary actuators with just two possible positions are examined next to actuators that can reach every possible intermediate position. For the latter, different control strategies are proposed. The displacement of the actuators can either be measured by external sensors or by using the change in resistance in the SMAs during transformation as feedback.     

In situ TEM studies of micron‐sized all‐solid‐state fluoride ion batteries: Preparation,prospects, and challenges

Trustworthy preparation and contacting of micron‐sized batteries is an essential task to enable reliable in situ TEM studies during electrochemical biasing. Some of the challenges and solutions for the preparation of all‐solid‐state batteries for in situ TEM electrochemical studies are discussed using an optimized focused ion beam (FIB) approach. In particular redeposition, resistivity, porosity of the electrodes/electrolyte and leakage current are addressed. Overcoming these challenges, an all‐solid‐state fluoride ion battery has been prepared as a model system for in situ TEM electrochemical biasing studies and first results on a Bi/La_0.9Ba_0.1F_2.9 half‐cell are presented. Microsc. Res. Tech. 79:615–624, 2016. © 2016 Wiley Periodicals, Inc.     

High-temperature measurements of lattice parameters and internal stresses of a creep-deformed monocrystalline nickel-base superalloy

High-temperature X-ray line profile measurements were performed to maximal temperatures of 1050 °C on samples of the nickel-base superalloy SRR 99. The samples with rod axes near the [001] direction were investigated in the initially undeformed state and after creep deformation at different temperatures and stresses. For the measurements of the (002) and (020) line profiles, a special X-ray double crystal diffractometer with negligible line broadening was used which was equipped with a high-temperature vacuum chamber. The line profiles were evaluated for the lattice parameters of the matrix phase γ and the precipitated γ′ phase and for values of the lattice mismatch parallel and perpendicular to the stress axis, respectively, which were found to be different. Elastic, tetragonal distortions of the phases γ and γ′ could be determined between room temperature and about 900 °C. These distortions are thermally induced due to the different thermal expansion coefficients of the two phases and deformation induced due to interfacial dislocation networks which were built up during deformation. At the high temperatures of the X-ray measurements, at least partial recovery of the deformation-induced internal stresses occurred, depending on the temperature of the X-ray measurements. The results are discussed and compared with data obtained by complementary techniques.     

Component Specifications for Robotics Integration

Robotics researchers have been unable to capitalize easily on existing software components to speed up their development efforts and maximize their system's capabilities. A component-based approach for building the software for robotics systems can provide reuse and sharing abilities to the research community. The software engineering community has been studying reuse techniques for three decades. We present several results from those efforts that are applicable to the robotics software integration problem. We describe how to specify a software component so that a potential user may understand its capabilities and facilitate its application to his or her system. At the National Institute of Standards and Technology, we have developed a three-stage, component-specification approach. We illustrate this approach for a component that is relevant to robotics.     

Sos, Vav, and C3G participate in B cell receptor-induced signaling pathways and differentially associate with Shc-Grb2, Crk, and Crk-L adaptors

B cell antigen receptor (BCR)-mediated signal transduction controls B cell proliferation and differentiation. The BCR activates Ras, presumably by the formation of a Shc-Grb2 adaptor complex, which recruits the Grb2-associated guanine nucleotide exchange factor Sos to the plasma membrane. In order to reveal additional BCR-induced signaling events involving the Grb2 adaptor, we undertook the isolation of Grb2-binding proteins. Using the yeast two-hybrid system and bacterial fusion proteins, Vav and C3G were identified as Grb2 binders. Vav is a putative nucleotide exchange factor and a target for BCR-induced tyrosine phosphorylation. C3G exerts nucleotide exchange activity on the Ras-related Rap1 protein. While Sos binds to both Grb2 Src homology-3 (SH3) domains, Vav was found to associate selectively with the carboxyl-terminal SH3 domain, while C3G bound selectively to the amino-terminal SH3 domain of bacterially expressed Grb2. Despite the association of Vav with Grb2 in vitro, we could not demonstrate an interaction between endogenous Vav and Grb2 molecules in primary B cells. Instead, Vav was found to inducibly associate with the Grb2-related adaptor protein Crk upon BCR stimulation. C3G did not bind to either Grb2, Shc, or Crk in vivo. Instead, C3G was found in association with the Crk-L adaptor, both before and after BCR stimulation. We show that Crk-L also participates in BCR signaling, since it inducibly interacts with tyrosine-phosphorylated Cbl. We conclude that, in addition to Sos, Vav and C3G play a role in BCR-mediated signal transduction. These guanine nucleotide exchange factors selectively associate with Grb2, Crk, and Crk-L, respectively, which may serve to direct them to different target molecules. Since Cbl binds to Grb2, Crk, as well as Crk-L, we hypothesize that Cbl may affect the function of all three exchangers.     

GPS – Global Positioning System

Ohne Zusammenfassung     

Evaluation of oligonucleotide probes for simple tandem repeats (STR) to produce informative DNA fingerprints of the chicken

Early intervention programs are designed to enhance the developmental competence of participants and to prevent or minimize developmental delays. Children targeted for early intervention may either include environmentally or biologically vulnerable children, or those with established developmental deficits. There is growing consensus based on the best available evidence that early interventions can exert moderate positive effects. However, this literature is limited by substantial methodological weaknesses in most studies. Therefore further randomized clinical trials are needed to ascertain which programs best meet the needs of children with or at risk for developmental disability.