Tailoring of Surfaces with Ultrathin Layers for Controlled Binding of Biopolymers and Adhesion and Guidance of Cells

Various strategies are described for the bio-functionalization of solid substrates by design of interfacial architectures. The first approach is based on the self-assembly process of long-chain thiol molecules from solution to a (noble) metal surface. If some of these building blocks carry a binding site (ligand) for proteins (receptors, antibodies, etc.) the metal surface can be tailored for maximum specific binding while simultaneously minimizing nonspecific adsorption. The second concept is based on polymers that are covalently attached to (oxide) surfaces. The preparation of these (end-) grafted functional polymers involves either the binding of preformed macromolecules to corresponding sites at the surface of the support or the recently introduced “grafting-from” method, by which an initiator molecule is first covalently bound to the surface and then activated — either by heat or light — in the presence of suitable monomer units such that a polymer chain grows from the solid/solution interface. Finally, the functionalization of patterned surfaces by peptide chains that mimic the binding domains of cell adhesion proteins is summarized. It is demonstrated that not only the selective adhesion of neuronal cells can then be controlled, but also their development with the outgrowth of dendrites and axons.     

The manufacture of high-value carbon from coal-tar pitch

World-wide, 17 million ta^?1 of coal-tar are obtained as a by product in the chamber coking process for the production of metallurgical coke. Refining of this aromatic raw material yields coal-tar pitch which is the traditional coal-derived starting material for the manufacture of carbon precursors and carbon artefacts. Considerable progress has been made in the elucidation of the physical and chemical nature of this material by means of chromatography, n.m.r. spectroscopy, thermal analysis and chemical reactions schemes. The dominant fields of application of pitch are the manufacture of pitch coke and electrode binders. Delayed coking and horizontal chamber coking are the technologies currently used for the production of cokes with low sulphur and metal content, for anodes for the aluminium-refining industry and the electric steel process. Coal-tar pitch, low in quinoline-insolubles (QI), is an excellent raw material for the manufacture of needle-cokes with a low coefficient of thermal expension (CTE). The separation of inherent QI can be performed via gravity settling in aliphatic hydrocarbon mixtures, by centrifugation in a disc separator or by filtration. The possible co-carbonization with aromatic petroleum-derived residues yields premium coke suitable for the manufacture of UHP-electrodes. New developments in the production of coke from coal-tar pitch aim to improve coke yields and increase anisotropy (i.e. low CTE and high electrical conductivity values). Further technological progress has been made in the manufacture of hard pitch which can be used as a starting material for the production of pitch coke in the chamber coking process and for the production of electrode binders by means of a continuous flash process with optimized thermal and pressure treatment of pitch, thus facilitating the ‘tailored’ manufacture of binder pitches of different qualities.     

7-(Dialkylamino)coumarin-4-yl]methyl-Caged Compounds as Ultrafast and Effective Long-Wavelength Phototriggers of 8-Bromo-Substituted Cyclic Nucleotides

[7-(Dimethylamino)coumarin-4-yl]methyl (DMACM) and [7-(diethylamino)coumarin-4-yl]methyl (DEACM) esters of 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) and 8-bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP) are described as novel caged compounds for 8-bromo-substituted cyclic nucleotides. Synthesis is accomplished by treatment of the free acids of the cyclic nucleotides with the corresponding 7(dialkylamino)-substituted 4(diazomethyl)coumarins. Irradiation of the DMACM- and DEACM-caged cyclic nucleotides with UV light stimulates the release of the cyclic nucleotides within roughly a nanosecond. The new caged compounds are resistant to hydrolysis in aqueous buffers and exhibit long-wavelength absorption properties with maxima at 400 nm, high extinction coefficients, and high quantum yields (0.15-0.31). Their favorable properties render these compounds the most efficient and rapid phototriggers of 8-bromo-substituted cyclic nucleotides known. The usefulness of the compounds for physiological studies under nondamaging light conditions was examined in HEK293 cells expressing the alpha subunit of the cyclic-nucleotide-gated (CNG) channel of cone photoreceptors (CNGA3) and of olfactory neurons (CNGA2) by using confocal laser scanning microscopy and the patch clamp technique.     

13C n.m.r. study of raw materials for carbon black

¹³C n.m.r. spectroscopy has been applied to investigate a number of coal tar and petroleum-derived carbon black feedstocks. Application of the J-modulated spin echo technique is especially rewarding, as this method renders the quaternary carbons directly detectable. Thus the quality of carbon black feedstocks can additionally be gauged on the basis of the contents of quaternary carbons, which is a direct indication of the carbon yield in the carbon black production process.     

Application of K2CO3 catalysts in the coal gasification process using nuclear heat

Conventional gasification processes use coal not only as feedstock to be gasified but also for supply of energy for reaction heat, steam production, and other purposes. With a nuclear high temperature reactor (HTR) as a source for process heat, it is possible to transform the whole of the coal feed into gas. This concept offers advantages over existing gasification processes: saving of coal, as more gas can be produced from coal; less emission of pollutants, as the HTR is used for the production of steam and electricity instead of a coal-fired boiler; and a lower production cost for the gas. However, the process has the disadvantage that the temperature is limited to the outlet temperature (950 °C max) of the helium cooling gas of the HTR. Therefore the possibility of catalytic steam gasification was examined. Model calculations based on experimental results show that use of 3–4 wt% relative to coal of K²CO³ catalyst increases the throughput of a large scale nuclear gasification plant by ≈65%, while gas production costs decrease by ≈15%. Corrosion by catalysts is not significant at low concentration (< 5 wt%) and low temperature (< 900 °C).     

Produkte der thermischen En-Reaktion von ungesättigten Fettstoffen und Maleinsäureanhydrid

Products of the Thermal Ene-Reaction of Unsaturated Fatty Compounds and Maleic Anhydride The thermal ene reaction of the methylates of unsaturated fatty acids 10-undecenoic acid, oleic acid and (E)-10-eicosendioic acid with maleic anhydride was carried out at 190°C. The mono addition products were isolated and their stereochemistry was deduced from ¹HNMR- and ¹³C-NMR-spectroscopy.     

Crack–Tip Toughness of a Soft Lead Zirconate Titanate

Crack–opening displacement (COD) measurements were performed on a commercial lead zirconate titanate (PZT). The intrinsic fracture toughness (or crack–tip toughness) of this material was determined using a new evaluation procedure, which takes into account the near–tip CODs and complete crack profile CODs. The crack–tip toughness K _I0 was determined from an extrapolation of COD data obtained at various loading stages, thus avoiding the complications caused by subcritical crack growth in PZT. Results for plane strain and plane stress condition are presented.     

Gewissensfreiheit in der Apotheke

Background In recent years, it has been intensively debated whether and how the conscience must be protected in the context of pharmacies. Currently, Germany and Austria have no legal regulation regarding this problem. Objective The ethical framework for a coping strategy dealing with the problem of freedom of conscience in the pharmacy will be outlined. Method By applying legal ethics' principle of proportionality within German and Austrian constitutional law as well as the European Convention on Human Rights, the problem is analyzed on its individual, corporative, and societal level. Results On the individual level, the pharmacist's and the patient's stakes and rights (e.g., the freedom of conscience) are carefully balanced by using the principle of proportionality. On the corporative level, the autonomy granted by the fundamental right of freedom of religion and belief legitimatizes a pharmacy's ideological profile as an organization and may cause conflicts of loyalty within the pharmacy. On the societal level, four pro-active options of shaping the legal framework are available: a social-welfare, a libertarian, a professional, and a communitarian. How conflicts on the individual or the corporative level can be solved depends on the option(s) that are chosen on the societal level. Conclusion If the status quo is to be changed, this article argues for two approaches: a) the introduction of a qualified conscience clause for pharmacists (including duties to consult, refer, treat in emergencies, and inform); b) a ‘weak’ communitarian option, striving for a compromise between a pharmaceutical corporation (i.e., pharmacy or pharmaceutical professional association) with an ideological profile and the public healthcare system. Both approaches satisfy a careful balancing of legitimate goods.     

Ausgleich der Volatilität der Erneuerbaren Energien mittels Wärmespeichern auf Salzbasis

To compensate for the volatility of renewable energies, solutions beyond fossil reserve power plants are needed. One approach is salt-based heat storage with phase change materials (PCM). In order to achieve economic efficiency, ambitious targets are required. A sensible and latent heat storage system for the temperature range around 400 °C based on salts and thermal oils with high development potential is presented.     

An investigation on wear behavior of UHMWPE/carbide composites at elevated temperatures

Ultra-high molecular weight polyethylene (UHMWPE) is extensively used in frictional applications due to its advanced wear resistance. This advanced polymer is reinforced with hard particulate fillers for further developments against wear conditions. Since elevated temperatures prevail in the service conditions, wear behavior of UHMWPE composites is an important issue for the engineering applications. In the present work, UHMWPE-based composites including silicon carbide (SiC) fillers were fabricated in a compression molding chamber. In the specimen preparation stage, molding pressure, filler amount, and filler particle size were varied to investigate the influence of these variables. Upon deciding the optimum parameters from the wear tests conducted at room temperature, the wear experiments were repeated for the optimum specimen at elevated temperatures, such as 40 and 60°C. According to the results, the wear behavior of the SiC/UHMWPE composites is heavily changed by the effect of elevated temperature. Adhesive effect is pronounced at elevated temperatures while the wear characteristics possess the abrasive effect in the sliding path. In addition, the composites exhibit an accelerated material loss as temperature increases during the frictional system.