20 Jahre in die Zukunft: Eine Zeitreise zu Trends und Entwicklungen auf dem Ökomarkt

Die vorgestellte Untersuchung ist ein kleiner Teil des Forschungsprojektes OMIaRD (Organic Marketing Initiatives and Rural Development), das innerhalb des fünften Rahmenprogramms der EU für Forschung und technologische Entwicklung finanziert wird. Teams von Universitäten und Instituten aus Großbritannien, Italien, Frankreich, der Schweiz, Finnland, Dänemark, Österreich und Deutschland bilden die Projektgruppe. Untersucht werden Aspekte der Vermarktung von Öko-Lebensmitteln in Europa. Der Schwerpunkt liegt hierbei auf Entwicklungspotentialen des ländlichen Raumes. OMIaRD verbindet zwei politische Hauptziele der EU: “nachhaltige Landwirtschaft” und “ländliche Entwicklung”. Abgeleitet werden praktische Vorschläge für Marketing- Initiativen und Daten zur Steuerung der Aktivitäten der Öffentlichen Verwaltungen im Bereich der Entwicklung des Ökomarkts als auch der Regionalentwicklung. Die Aufgabe des Teams der HAW Hamburg ist die europaweite Koordination und nationale Durchführung von Gruppendiskussionen zu Trends und Entwicklungen des Verbraucherverhaltens in Bezug auf Öko-Lebensmittel. Die Teilnehmer prognostizieren der 'Öko-Welt' keinen kühnen Aufbruch zu neuen Ufern, sondern einen mühsamen, steinigen Weg, allerdings mit leichtem Aufwärtstrend. Denn: Öko kann nicht schneller wachsen, als sich Verbraucher ändern

Waveguide Fabrication In UV-Photocurable Sol–Gel Materials: Influence Of The Photoinitiating System

In this paper we identify and explain the different chemical interactions involved between a sol–gel matrix and photoinitiators used in the fabrication of optical waveguides. A well-established sol–gel matrix composed of 3-methacryloxypropyltrimethoxysilane, zirconium n-propoxide and methacrylic acid was developed, and two different photoinitiators (Irgacure® 819 and 1800) were added to the host matrix. Optical microscopy was used to characterise the structure of the waveguides as a function of the photoinitiator nature and concentration, and aging of the hybrid sol–gel material. It is clearly demonstrated that the width of the waveguides is strongly influenced by the sol aging. Furthermore, it is shown that degradation of photoinitiators occurs during the sol–gel process. Oxidation of the phosphonyl groups by the zirconium complex accounts for this results

Photoinduced hydrosilylation through hydrogen abstraction: an NMR and computational study of the structural effect of silane

The hydrosilylation reaction, describing the addition of Si–H bonds to unsaturated bonds, is performed in the presence of catalysts, usually highly active platinum catalysts. This work focuses on the study of a photoinduced hydrosilylation by the use of benzophenone which promotes the addition reaction of olefin on different hydrosilanes. The reactivity of silanes towards addition onto the double bond during hydrosilylation appears to depend on their structure. It was observed that the consumption of Si–H and C[double bond, length as m-dash]C functional groups increases with the irradiation time, and reaches a maximum of approx. 51% in the case of diphenylsilane. The hydrosilylation products are determined with (1)H NMR, HSQC, DEPT, COSY and (13)C NMR. The main product corresponds to the single adduct of the silyl radical onto the double bond. Substitution of the Si–H bond by two or three phenyls groups (triphenylsilane, diphenysilane) enhances the yield of the reaction, although diphenylsilane was found to be more efficient than triphenylsilane because of its lower steric hindrance. The ketyl radical formed after hydrogen abstraction by the triplet state of benzophenone likely forms benzopinacol, a reaction which reduces the overall yield of the hydrosilylation reaction. All these experiments are in line with DFT calculations of the Gibbs free energy of the reactions involved. This sheds new light on the photoinduced hydrosilylation process and opens the way to more active combinations of photoinitiator/silane/vinylsilane systems

Expression and purification of tau protein and its frontotemporal dementia variants using a cleavable histidine tag

Recombinant tau protein is widely used to study the biochemical, cellular and pathological aspects of tauopathies, including Alzheimer's disease and frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTPD-17). Pure tau in high yield is a requirement for in vitro evaluation of the protein's physiological and toxic functions. However, the preparation of recombinant tau is complicated by the protein's propensity to aggregate and form truncation products, necessitating the use of multiple, time-consuming purification methods. In this study, we investigated parameters that influence the expression of wild type and FTPD-17 pathogenic tau, in an attempt to identify ways to maximise expression yield. Here, we report on the influence of the choice of host strain, induction temperature, duration of induction, and media supplementation with glucose on tau expression in Escherichia coli. We also describe a straightforward process to purify the expressed tau proteins using immobilised metal affinity chromatography, with favourable yields over previous reports. An advantage of the described method is that it enables high yield production of functional oligomeric and monomeric tau, both of which can be used to study the biochemical, physiological and toxic properties of the protein

Direct-to-metal UV-cured hybrid coating for the corrosion protection of aircraft aluminium alloy

Finding eco-efficient and environmentally viable alternatives to chromate coatings represents a fundamental milestone in the aerospace industry. Here, we show a chromate-free approach to protective hybrid coatings on aluminium alloy (AA2024-T3) departing from photoinduced sol–gel and cationic polymerizations. Beginning with a film of n-alkyltrimethoxysilane and diepoxy monomer, we rely on photogenerated superacids to induce the single step formation of two inorganic and organic barrier networks. Such system combines the unique aspects of photopolymerization including fast reactions, temporal control, solvent-free composition and temperature independence. Used without chemical conversion coating or anodizing, some films have passed 2000h of salt spray testing

Profiles of SUMO and ubiquitin conjugation in an Alzheimer's disease model

► Global levels of ubiquitinated proteins increased in the hippocampus of Tg2576 mice. ► No global changes in either SUMO-1 or SUMO-2/3 conjugation in any brain regions analysed. ► SUMO conjugating and deconjugating enzymes, UBC9 and SENP-1, unaltered in Tg2576 mice. ► Total levels of AMPA and kainate receptors were also unaffected in Tg2576 mice. ► Posttranslational modification by ubiquitin may play a role in Alzheimer's disease

Caractérisation des propriétés mécaniques de vernis photopolymères par micro-indentation et simulation par éléments finis.

Afin de caractériser les propriétés mécaniques de vernis photopolymérisés d’épaisseurs 15 et 80 µm, des essais par Analyse Mécanique Dynamique (D.M.A.) et par micro-indentation ont été menés. Les résultats expérimentaux sont confrontés au moyen de simulations par éléments finis (Abaqus). Un premier modèle viscoélastique a permis de simuler correctement la charge et le plateau de fluage, mais s’avère insuffisant pour simuler la décharge

Role of electrostatic interactions in amyloid beta-protein (Abeta) oligomer formation: A discrete molecular dynamics study

Pathological folding and oligomer formation of the amyloid beta-protein (Abeta) are widely perceived as central to Alzheimer's disease (AD). Experimental approaches to study Abeta self-assembly are problematic, because most relevant aggregates are quasi-stable and inhomogeneous. We apply a discrete molecular dynamics (DMD) approach combined with a four-bead protein model to study oligomer formation of the amyloid beta-protein (Abeta). We address the differences between the two most common Abeta alloforms, Abeta40 and Abeta42, which oligomerize differently in vitro. We study how the presence of electrostatic interactions (EIs) between pairs of charged amino acids affects Abeta40 and Abeta42 oligomer formation. Our results indicate that EIs promote formation of larger oligomers in both Abeta40 and Abeta42. The Abeta40 size distribution remains unimodal, whereas the Abeta42 distribution is trimodal, as observed experimentally. Abeta42 folded structure is characterized by a turn in the C-terminus that is not present in Abeta40. We show that the same C-terminal region is also responsible for the strongest intermolecular contacts in Abeta42 pentamers and larger oligomers. Our results suggest that this C-terminal region plays a key role in the formation of Abeta42 oligomers and the relative importance of this region increases in the presence of EIs. These results suggest that inhibitors targeting the C-terminal region of Abeta42 oligomers may be able to prevent oligomer formation or structurally modify the assemblies to reduce their toxicity.Comment: Accepted for publication at Biophysical Journa

Experimental and theoretical investigations of free radical photopolymerization: Inhibition and termination reactions

In this work, the inhibition and termination reactions occurring throughout a free radical photopolymerization initiated by a type-I photoinitiator are studied by kinetic modeling. The role of the macroradicals as the main oxygen trapping agents during the inhibition time is identified, and the absence of primary radical consumption by oxygen can be related to a high initiation efficiency at early times. The ratio of the termination reactions reveals that bimolecular termination remains the principal pathway for the cessation of macromolecule growth, even at high polymer conversion. Moreover, the evolution of the termination ratio during the polymerization can be correlated to both the diffusional control of the polymerization reactions as the polymer network grows and the photoinitiator consumption. Finally, the effect of the incident light intensity and the initial photoinitiator concentration on the termination reactions is assessed, and the validity of the steady-state assumption applied to the macroradical concentration discussed

Mapping interactions with the chaperone network reveals factors that protect against tau aggregation.

A network of molecular chaperones is known to bind proteins ('clients') and balance their folding, function and turnover. However, it is often unclear which chaperones are critical for selective recognition of individual clients. It is also not clear why these key chaperones might fail in protein-aggregation diseases. Here, we utilized human microtubule-associated protein tau (MAPT or tau) as a model client to survey interactions between ~30 purified chaperones and ~20 disease-associated tau variants (~600 combinations). From this large-scale analysis, we identified human DnaJA2 as an unexpected, but potent, inhibitor of tau aggregation. DnaJA2 levels were correlated with tau pathology in human brains, supporting the idea that it is an important regulator of tau homeostasis. Of note, we found that some disease-associated tau variants were relatively immune to interactions with chaperones, suggesting a model in which avoiding physical recognition by chaperone networks may contribute to disease