DNA Primer Extension with Cyclopropenylated 7‐Deaza‐2′‐deoxyadenosine and Efficient Bioorthogonal Labeling in Vitro and in Living Cells

A deoxyadenosine triphosphate (dATP) analogue for DNA labeling was synthesized with the 1‐methylcyclopropene (1MCP) group at the 7‐position of 7‐deaza‐2′‐deoxyadenosine and applied for primer extension experiments. The real‐time kinetic data reveals that this 1MCP‐modified dATP analogue is incorporated into DNA much faster than that of the similarly 1MCP‐modified deoxyuridine triphosphate (dUTP) analogue. The postsynthetic fluorescent labeling of these oligonucleotides works efficiently according to PAGE analysis, and can be applied for immobilization of a functional antibody on a surface. Site‐specific labeling at two different positions in DNA was achieved and the bioorthogonality of the postsynthetic fluorescent labeling was demonstrated in living HeLa cells.     

Structure,stability and permeation properties of NaA zeolite membranes for H2O/H2 and CH3OH/H2 separations

NaA zeolite membranes were synthesised in the secondary growth hydrothermal method based on the seeding of the inner surface of a ceramic α-alumina tube. The impacts of crystallisation time and zeolite precursor concentration (in H₂O) were investigated. The structure and stability of the prepared NaA zeolite membranes were also investigated with operating temperatures, times and pressures. The results indicate that the optimal synthesis gel molar composition was 3Na₂O: 2SiO₂: Al₂O₃: 200H₂O. This led to cubic-shaped NaA zeolite which showed good stability. The optimal NaA zeolite membrane had H₂O and CH₃OH fluxes of 2.77 and 0.19 kg/m²h, with H₂O/H₂ and CH₃OH/H₂ separation factors of ∞ and 0.09 at a temperature of 30 °C. The NaA zeolite membrane had high thermal stability, but poor separation performance at high temperature (240 °C). The results suggested that the H₂ permeation flux is significantly influenced by preferential adsorption of vapour in the NaA zeolite membrane.     

Electro-dissolution of 30Nb–Ti alloys in methanolic sulfuric acid—Optimal conditions for electropolishing

The electro-dissolution behaviour of a (30 at.%) Niobium–Titanium (NbTi) alloy in non-aqueous methanolic sulfuric acid solution using the rotating disc electrode (RDE) was ascertained. The optimal condition for electropolishing and the mechanism were proposed. The influence of the rotation rate, process temperature and sulfuric acid concentration on the dissolution kinetics was investigated. The dissolution rate (limiting current) increases linearly with increase in rotation rate and follows a Levich behaviour confirming a mass transport controlled process. The temperature dependence in terms of Arrhenius plot renders an activation energy value of E_a = 16.1 kJ mol⁻¹ for the process. The dissolution rate shows a strong dependence on the sulfuric acid concentration (1 M, 3 M and 5 M). Higher sulfuric acid concentrations lead to decreased dissolution rates (limiting current). The dissolution process is mass transport controlled in all concentrations of sulfuric acid. From an electrochemical perspective, a 3 M sulfuric acid was chosen as optimum owing to better controllability of the material removal rate. The dissolving ions are the probable rate limiting species, indicating a compact salt-film mechanism. The average root mean square (RMS) roughness value for an electropolished surface was approximately 10 nm, which is significantly lower than a mechanically polished surface.     

Strategien zum Schließen der Stoffkreisläufe beim Recycling von Fluorpolymeren

In fluoropolymers, a large portion or even all of the hydrogen atoms in a polymer chain are replaced by fluorine, which results in a number of special properties such as high chemical and temperature resistance. As a result of this combination of properties, these high-performance polymers are not replaceable, or only with difficulty, for some applications. The recycling of polymers and the associated closing of material loops is an essential development task for the entire polymer industry. Materials such as fluoropolymers have a special position due to their chemical composition and their low market volume, as they cannot be recycled together with other bulk polymers at the end of their life cycle. This paper discusses different processes in terms of their technical maturity and suitability to allow fluoropolymers to be fully recycled.     

A ¹⁸F-labeled fluorobutyl-substituted spirocyclic piperidine derivative as a selective radioligand for PET Imaging of sigma₁ receptors

In this study, we synthesized and evaluated a new spirocyclic piperidine derivative 3 , containing a 4‐fluorobutyl side chain, as a PET radioligand for neuroimaging of σ₁ receptors. In vitro, compound 3 displayed high affinity for σ₁ receptors (K_i=1.2 nM ) as well as high selectivity. [¹⁸F] 3 radiosynthesis was performed from the corresponding tosylate precursor, with high radiochemical yield (45–51 %), purity (>98 %), and specific activity (>201 GBq μmol^?1). Metabolic stability of [¹⁸F] 3 in the brain of CD‐1 mice was verified, and no penetration of peripheral radiometabolites into the cerebral tissue was observed. Results of ex vivo autoradiography revealed that the distribution of [¹⁸F] 3 in the brain corresponded to regions with high σ₁ receptor density. The highest region‐specific total‐to‐nonspecific ratio was determined in the facial nucleus (4.00). Biodistribution studies indicated rapid and high levels in brain uptake of [¹⁸F] 3 (2.2 % ID per gram at 5 min p.i.). Pre‐administration of haloperidol significantly inhibited [¹⁸F] 3 uptake into the brain and σ₁ receptor‐expressing organs, further confirming in vivo target specificity.     

Zur Feuchteproblematik in Eissporthallen

Aufgrund vieler Untersuchungen zur Standsicherheit von Eissporthallen wurde festgestellt, dass diese in unterschiedlichem Maße saniert werden müssen. Die Holzfeuchtigkeit der Tragkonstruktionen betrug meistens langanhaltend über 20 %. Daher wurden Untersuchungen zu den Ursachen hoher Holzfeuchten in Eissporthallen durchgeführt. Eine der Ursachen liegt in dem Strahlungsaustausch zwischen der Hallendecke und der Eisfläche. Zu dieser Problematik wurden Versuche durchgeführt und daraus mögliche Verbesserungsvorschläge für Eissporthallen abgeleitet. About the humidity problem in ice rinks. After expertising the structural safety of several ice rinks, it was detected that the constructions of several buildings have to be redeveloped. The long lasting wood moisture of the main structure was predominantly over 20 %. Therefore research into the reason of high wood moisture in ice rinks was made. One fact is the exchange of radiation between the ceiling and the ice. This problem was analysed in tests and suggestions for improvement are made.