Pyrrolizidinalkaloide in Honig und Pollen

Pyrrolizidine alkaloids (PA) are secondary plant constituents which comprise about 370 different structures, occurring in two major forms, a tertiary form and the corresponding N-oxide. PA containing a 1,2-double bond are pre-toxins and metabolically activated by the action of hepatic P-450 enzymes to acute toxic and genotoxic pyrroles. Beside the acute toxic effects, the genotoxic and tumorigenicity potential of PA was demonstrated in some eukaryotic model systems. Recently, the potentially PA contamination of food and feeding stuff attracted recurrent great deals of attention. Humans are exposed to these toxins by consumption of herbal medicine, herbal teas, dietary supplements or food containing PA-plant-material. In numerous studies the potential threat to human health by PA is stated. In pharmaceuticals, the use of these plants is regulated. Considering the values observed especially in authentic honey from PA producing plants and pollen products, the results provoke the discussion of an international regulation of PA in food.     

Sparse Deconvolution Methods for Ultrasonic NDT

In this work we present two sparse deconvolution methods for nondestructive testing. The first method is a special matching pursuit (MP) algorithm in order to deconvolve the mixed data (signal and noise), and thus to remove the unwanted noise. The second method is based on the approximate Prony method (APM). Both methods employ the sparsity assumption about the measured ultrasonic signal as prior knowledge. The MP algorithm is used to derive a sparse representation of the measured data by a deconvolution and subtraction scheme. An orthogonal variant of the algorithm (OMP) is presented as well. The APM technique also relies on the assumption that the desired signals are sparse linear combinations of (reflections of) the transmitted pulse. For blind deconvolution, where the transducer impulse response is unknown, we offer a general Gaussian echo model whose parameters can be iteratively adjusted to the real measurements. Several test results show that the methods work well even for high noise levels. Further, an outlook for possible applications of these deconvolution methods is given.     

The 3D nanometer device project nextnano: Concepts, methods, results

nextnano is a simulation tool that aims at providing global insight into the basic physical properties of realistic three-dimensional mesoscopic semiconductor structures. It focuses on quantum mechanical properties such as the global electronic structure, optical properties, and the effects of electric and magnetic fields for virtually any geometry and combination of semiconducting materials. For the calculation of carrier dynamics, two models are currently implemented that provide results for the limiting cases of highly diffusive or purely ballistic quantum-mechanical transport. In this paper, we present an overview of nextnano's present and future capabilities and discuss some key concepts in the areas of code structure, numerical techniques, and electronic structure principles.     

Fluorescence Lifetime Imaging of Quantum Dot Labeled DNA Microarrays

Quantum dot (QD) labeling combined with fluorescence lifetime imaging microscopy is proposed as a powerful transduction technique for the detection of DNA hybridization events. Fluorescence lifetime analysis of DNA microarray spots of hybridized QD labeled target indicated a characteristic lifetime value of 18.8 ns, compared to 13.3 ns obtained for spots of free QD solution, revealing that QD labels are sensitive to the spot microenvironment. Additionally, time gated detection was shown to improve the microarray image contrast ratio by 1.8, achieving femtomolar target sensitivity. Finally, lifetime multiplexing based on Qdot525 and Alexa430 was demonstrated using a single excitation-detection readout channel.     

Costimulation through CD86 is involved in airway antigen-presenting cell and T cell responses to allergen in atopic asthmatics

Atopic allergic asthma is characterized by activation of Th2-type T cells in the bronchial mucosa. Previous reports have suggested an important role for costimulation through the CD28/CTLA4-CD80/CD86 pathway in allergen activation of T cells in animal models of inhaled allergen challenge. However, human allergen-specific lines and clones were reported to be costimulation independent. We therefore examined CD80 and CD86 dependence of allergen-induced T cell proliferation and cytokine production in peripheral blood and bronchoalveolar lavage from atopic asthmatic subjects and controls. Both allergen-induced proliferation and IL-5 production from PBMC were inhibited by CTLA4-Ig fusion protein and anti-CD86, but not anti-CD80 mAbs. When allergen-specific CD4+ T cell lines from peripheral blood were examined, proliferation and cytokine production were found to be independent of CD80 or CD86 costimulation. However, when cells obtained directly from the airways were examined, allergen-induced proliferation of bronchoalveolar lavage T cells from atopic asthmatic subjects was inhibited by anti-CD86 but not anti-CD80. In addition, bronchoalveolar lavage-adherent cells from asthmatic, but not control subjects showed APC activity to autologous T cells. This was also inhibited by anti-CD86 but not anti-CD80. Thus allergen-induced T cell activation and IL-5 production in the airway in asthmatic subjects is susceptible to blockade by agents interfering with costimulation via CD86, and this may hold therapeutic potential in asthma.     

MoneyBee: Aktienkursprognose mit künstlicher intelligenz bei hoher rechenleistung

The company i42 GmbH, Mannheim, developed MoneyBee: a system to predict stock market values, basing on artificial intelligence (neural networks), distributed computing and different applications to optimize the input- and output-data (e.g. genetic algorithms, statistical methods). More than 200 values (especially from German stock market) are observed by this system continuously, with daily updated predictions. The information technology product is an innovation — not by its basic technology, but by its cooperation of different program groups on high level.     

Modeling of thermo-physical properties for FRP composites under elevated and high temperature

A decomposition model for resin in glass fiber-reinforced polymer composites (GFRP) under elevated and high temperature was derived from chemical kinetics. Kinetic parameters were determined by four different methods using thermal gravimetric data at different heating rates or only one heating rate. Temperature-dependent mass transfer was obtained based on the decomposition model of resin. Considering that FRP composites are constituted by two phases – undecomposed and decomposed material – temperature-dependent thermal conductivity was obtained based on a series model and the specific heat capacity was obtained based on the Einstein model and mixture approach. The content of each phase was directly obtained from the decomposition model and mass transfer model. The effects of endothermic decomposition of the resin on the specific heat capacity and the shielding effect of evolving voids in the resin on thermal conductivity are dependent on the rate of decomposition. They were also described by the decomposition model; the effective specific heat capacity and thermal conductivity models were subsequently obtained. Each model was compared with experimental data or previous models, and good agreements were found.     

Engineering the substrate specificity of the Abl tyrosine kinase

c-Abl is a non-receptor tyrosine kinase that is involved in a variety of signaling pathways. Activated forms of c-Abl are associated with some forms of human leukemia. Presently, no high resolution structure of the tyrosine kinase domain of Abl is available. We have developed a structural homology model of the catalytic domain of Abl based on the crystal structure of the insulin receptor tyrosine kinase. Using this model as a guide, we selected residues near the active site predicted to play a role in peptide/protein substrate recognition. We expressed and purified 15 mutant forms of Abl with single amino acid substitutions at these positions and tested their peptide substrate specificity. We report here the identification of seven residues involved in recognition of the P-1, P+1, and P+3 positions of bound peptide substrate. Mutations in these residues cause distinct changes in substrate specificity. The results suggest features of Abl substrate recognition that may be relevant to related tyrosine kinases.