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Aiming at the design of highly brilliant NIR emissive optical probes, e.g., for in vivo near-infrared fluorescence imaging (NIRF), we studied the absorption and fluorescence properties of the asymmetric cyanines Dy678, Dy681, Dy682, and Dy676 conjugated to the model antibody IgG. The ultimate goal was here to derive general structure–property relationships for suitable NIR fluorescent labels. These Dy dyes that spectrally match Cy5 and Cy5.5, respectively, were chosen to differ in chromophore structure, i.e., in the substitution pattern of the benzopyrylium end group and in the number of sulfonic acid groups. Spectroscopic studies of the free and IgG-bound fluorophores revealed a dependence of the obtained dye-to-protein ratios on dye hydrophilicity and control of the fluorescence quantum yields (Φf) of the IgG conjugates by the interplay of different fluorescence reduction pathways like dye aggregation and fluorescence resonance energy transfer (FRET). Based upon aggregation studies with these dyes, the amount of dye dimers in the IgG conjugates was determined pointing to dye hydrophilicity as major parameter controlling aggregation. To gain further insight into the exact mechanism of dye dimerization at the protein, labeling experiments at different reaction conditions but constant dye-to-protein ratios in the reaction solution were performed. With Dy682 that displays a Φf of 0.20 in PBS and 0.10 for moderate dye-to-protein ratio of 2.5, a low aggregation tendency, and a superior reactivity in IgG labeling, we identified a promising diagnostic tool for the design of NIR fluorescent probes and protein conjugates.
In structural engineering timber is appreciated due to its low weight, its high aesthetic quality and because it is a renewable resource. The market share of timber structures and wood based hybrid structures will clearly increase over the next few years due to greater environmental awareness and a higher demand for sustainability. However, building with timber is marked by characteristics which lead to significant disadvantages in comparison wifh technical materials. For example, in outdoor areas Chemical and structural approaches offen lead to unsatisfactory and expensive Solutions with respect to durability. An idea is to make natural lumber a high-performance material which can be designed to meet the engineers’ demands conceming strength, stiffness, durability, shape, safety etc. These changes can affect the material itself, new technologies or a new approach to monitoring. Especially hybrids made of common timber products and technical textiles or enhanced timber products are high-capacitive and reach high bearing strengths with low material input and good durability. These hybrids are particularly qualified to use the advantages of wood and minimize the disadvantages. They can be used in different ways for load bearing structures, i.e. bridges. New construction types need monitoring to observe the stress and strains for which they were designed, and the structures’ behaviour as well as to guarantee required safety levels. The aim of successful usage of fibre optic measurement technology in timber elements was the development of a technology for measuring the lengthening in timber elements and wood based hybrid elements by using fibre optic sensors. The scientific and technical challenge was to develop an applicationtechnology for optical glass fibres in timber and densified veneer wood.
In laboratory tests as well as with the erection of a footbridge and during in-situ tests it could be shown that the structurally integrated fibre optic sensor technology used is suitable for short and long term measurement. The developed embedment technology tums out to be practical and fit for good transfer of strain-values from timber to the modified sensor fibres.
One of the typical wastes produced in blast-furnace (BF) ironmaking is BF sludge, which mostly consists of carbon and iron oxides, but also contains toxic trace metals such as Zn, Pb, Cd, As, and Hg that render the material hazardous. Due to the lack of an established recycling process, BF sludges are landfilled, which is ecologically questionable and costly. Here, we investigate selective removal of Zn, Pb, and Cd from BF sludge by chlorination–evaporation reactions using thermodynamic modelling and laboratory-scale experiments. Specifically, BF sludge was thermochemically treated at 650–1000 °C with a spent iron(II) chloride solution from steel pickling and the effects of process temperature and retention time on removal of Zn, Pb, and Cd were investigated. Zinc and Pb were quantitatively removed from BF sludge thermochemically treated at 900–1000 °C, whereas Fe and C as well as other major elements were mostly retained. The Zn, Pb, and Cd contents in the thermochemically treated BF sludge could be lowered from ∼56 g/kg, ∼4 g/kg, and ∼0.02 g/kg to ≤0.7 g/kg, ≤0.02 g/kg, and ≤0.008 g/kg, respectively, thus rendering the processed mineral residue a non-hazardous raw material that may be re-utilized in the blast furnace or on the sinter band.