Luminescent Conjugated Oligothiophenes for Sensitive Fluorescent Assignment of Protein Inclusion Bodies

Small hydrophobic ligands identifying intracellular protein deposits are of great interest, as protein inclusion bodies are the pathological hallmark of several degenerative diseases. Here we report that fluorescent amyloid ligands, termed luminescent conjugated oligothiophenes (LCOs), rapidly and with high sensitivity detect protein inclusion bodies in skeletal muscle tissue from patients with sporadic inclusion body myositis (s‐IBM). LCOs having a conjugated backbone of at least five thiophene units emitted strong fluorescence upon binding, and showed co‐localization with proteins reported to accumulate in s‐IBM protein inclusion bodies. Compared with conventional amyloid ligands, LCOs identified a larger fraction of immunopositive inclusion bodies. When the conjugated thiophene backbone was extended with terminal carboxyl groups, the LCO revealed striking spectral differences between distinct protein inclusion bodies. We conclude that 1) LCOs are sensitive, rapid and powerful tools for identifying protein inclusion bodies and 2) LCOs identify a wider range of protein inclusion bodies than conventional amyloid ligands.     

Engineering HC-SCR: Improved Low Temperature Performance through a Cascade Concept

A catalytic after treatment system for lean HC-SCR was constructed of two different catalyst beds, e.g. of a Ag/alumina and Cu-ZSM-5 catalyst (cascade concept). The improved activity especially at low temperature range was found to be due to the synergetic effect of the two catalysts, which combines the transformation of the feed gas over Ag/alumina to such compounds that are highly reactive towards N₂ over Cu-ZSM-5. The effluent coming from the Ag/alumina bed was analysed by GC–MS along with the NO to N₂ conversion over the whole system by GC. The results obtained from the GC–MS measurements revealed that hydrocarbon used as a reducing agent is oxidised and that besides oxygenates also various N-containing hydrocarbons are formed over the Ag/Al₂O₃.     

Single and bi-metallic silver modified ZSM-5 for waste gases neutralization

Single and bi-metallic silver modified ZSM-5 catalysts were synthesized using three methods of preparation, characterized by different techniques: X-ray powder diffraction (XRD), scanning electron microscopy (SEM), nitrogen physisorption, X-ray fluorescence (XRF), inductively coupled plasma atomic emission spectrometry (ICP-AES) and tested in heterogeneous catalytic decomposition of ozone at ambient temperature. The highest degree of ozone decomposition was observed over 5Ag(Imp)-H(IE)-ZSM-5 catalyst, which exhibit 97% conversion and does not show any deactivation with the time. The method of preparation, amount of supported silver and the presence of modifiers as Cu, Ce, and Zr were found to be important for the ozone decomposition reaction.     

A combination of Ag/alumina and Ag modified ZSM-5 to remove NOx and CO during lean conditions

Single and bi-metallic silver modified ZSM-5 catalysts were synthesized using different methods of preparation, characterized by several techniques and tested in simulated diesel conditions. Additionally the catalytic behaviour of the most active catalyst, containing 5 wt.% Ag and prepared by impregnation (5Ag(Imp)-H-ZSM-5), was studied over a broad temperature range with two reducing agents (octane and propene). To correlate the catalytic activity of the prepared catalysts with preparation parameters the materials were characterized by XRD, SEM, N₂-physisorption, octane/propene-TPD, EPR and ICP techniques. A dual bed system consisting of Ag/alumina and the most active zeolitic material (5Ag(Imp)-H-ZSM-5) was shown not only to substantially enhance the activity of Ag/alumina in the low temperature region, but also to completely oxidize the CO and unburned hydrocarbons.     

Toward improved catalytic low-temperature NOx removal in diesel-powered vehicles

The potential of different catalytic after treatment techniques to meet future diesel emission standards, which are strongly shifted toward urban driving conditions including cold start, are critically discussed in this Account and evaluated for their suitability for commercial applications. The dominating techniques in this field are NO(x) storage, urea-selective catalytic reduction (SCR), and HC-SCR. Each of these techniques have significant disadvantages such as sulfur sensitiveness and regeneration requirements of NO(x)-storage materials, infrastructure issues and formation of ammonium nitrate (at low temperatures) for urea-SCR, and low-temperature activity of HC-SCR catalysts. Ways to overcome these disadvantages in commercial applications may involve optimized regeneration strategies, reactor modifications, flow reversal, closed-loop NO(x) feedback systems, nonthermal plasma, and/or hydrogen-assisted catalyses, etc.     

On the syntheses of branched saturated fatty acids

In order to investigate the relation between the structure of mono-branched saturated fatty acids and their physical properties, a three-factor central composite design was constructed. For this purpose sixteen different fatty acids were prepared. The synthetic strategy was to use if possible, a few common starting materials for the preparation of most of the acids. Thus alkylation and hydrolysis of oxazolines were used for the preparation of 2-butylhexanoic acid, 2-methyloctadecanoic acid, 2-hexadecyloctadecanoic acid and 2-pentyloctadecanoic acid. A number of acids were prepared from thiophene derivatives followed by desulfurization with Raney-Nickel alloy under alkaline conditions. Thus, starting from 3-ethylthiophene, 4-ethyl-2-thiophenecarboxylic acid and 4-ethyl-2-methyl-5-thiophenecarboxylic acid were prepared, which upon desulfurization gave the desired 4-methylhexanoic acid. From 3-bromo-2-methylthiophene, 3-ethyl-2-methyl-5-thiophenecarboxylic acid was preparedvia 3-acetyl-2-methylthiophene and 3-ethyl-2-methylthiophene. Desulfurization gave 4-ethylhexanoic acid. Another approach started with 2-acylthiophenes, which were reacted with Grignard reagent to yield the appropriate olefins. By metalation and reaction with carbon dioxide, these were transformed to the corresponding 2-thiophenecarboxylic acids. Upon desulfurization, the desired fatty acids were obtained. In this way 6-propyldecanoic acid, 6-hexyldodecanoic acid, 6-methyldodecanoic acid and 6-pentylpentadecanoic acid were prepared. The remaining four acids were prepared from some of the branched acids described above through Kolbe reactions of dioic acids. Thus 16-methyloctadecanoic acid and 10-methyl-dodecanoic acid were obtained from 4-methylhexanoic acid, 16-ethyloctadecanoic acid from 4-ethylhexanoic acid and 9-pentyloctadecanoic acid from 6-pentylpentadecanoic acid.     

A highly active Ag/alumina catalytic converter for continuous HC-SCR during lean-burn conditions: from laboratory to full-scale vehicle tests

Topics in Catalysis - A common-rail diesel vehicle was equipped with a full-scale Ag/alumina catalytic converter. The converter consisted of several Ag/alumina bricks, with free space in between...     

On the syntheses of triacylglycerols from branched saturated fatty acids

A number of triacylglycerols with branched acyl groups were prepared via 1,2-isopropylidene glycerol for the purpose of studying three different physical properties: gel point, refractive index, and density. The monoacid triacylglycerols were prepared either via the corresponding acids or the acyl chlorides.     

Silver/Alumina Catalyst for Selective Catalytic Reduction of NO x to N2 by Hydrocarbons in Diesel Powered Vehicles

Ag/alumina has been found to be a promising catalyst for the selective catalytic reduction of NO _x to N₂ by hydrocarbons (HC-SCR) in laboratory tests as well as in full-scale diesel engine operation. The steps in developing an active silver catalyst for practical applications involve knowledge of the mechanism, choice of the right metal content and correct support, adjustment of the concentration of the hydrocarbon to be used for reduction reactions etc. As gas phase reactions seem to play a significant role in obtaining high NO to N₂ conversion, also reactor aspects have to be included in the optimisation procedure of a full size Ag/alumina catalytic converter.     

Preparation and Characterisation of Ag/Alumina Catalysts for the Removal of NOx Emissions Under Oxygen Rich Conditions

A highly active silver/alumina catalyst for continuous reduction of NO to nitrogen with octane under lean conditions was prepared. The effect of impregnation time and precursor concentration on the catalyst activity was investigated. The catalyst was characterized by means of XRF, H₂-TPR, and UV–Vis to correlate recorded results with different preparation methods. UV–Vis measurements indicated that the highest and most stable activity is obtained with Ag/alumina exhibiting predominantly mono-atomically dispersed silver.