Gemeinsame kondensation von harnstoff,melamin und formaldehyd. I. Einfluß der reaktionsparameter

The dependance of the simultaneous polycondensation of urea, melamine, and formaldehyde on reaction conditions was studied using chromatographic and spectroscopic methods. The results indicate an increase in the reactivity between urea and formaldehyde and also between melamine and formaldehyde with increasing acidity. A. controllable reaction involving simultaneously urea, melamine, and formaldehyde was possible only in neutral and basic media. An increasing proportion of urea in the reaction mixture increases the degree of polycondensation. A comparison of the three-component-resin with the UF-and MF-resins gives information pertaining to the formation of cocondensats consisting of urea and melamine. Acetone dilutability and turbidimetric measurements are in agreement with the results of chromatographic and spectroscopic methods.     

Analytic Two-Fluid Description of Unconventional Superconductivity

This paper considers the problem of finding simple analytical forms for the temperature dependence of thermodynamic and response functions within the weak coupling theory of clean unconventional superconductors. In particular we derive interpolation formulae for the entropy, specific heat, spin susceptibility and current of the normal component, formed by the thermal excitations (Bogoliubov quasiparticles), as well as for the superfluid density and hence the magnetic penetration depth, describing the response of the condensate. The results apply to unconventional superconductors as well as to unconventionally paired systems like the A-phase of superfluid ³He.     

Controlled free‐radical polymerization of vinyl chloride

Owing to the importance of poly(vinyl chloride) (PVC) as the second‐largest plastic in volume after the polyolefins and above styrene polymers, the control of the free‐radical polymerization of vinyl chloride (VC) is of high industrial and academic interest. But still the term “controlled” polymerization is not yet clearly defined. Often it is used for quasi‐living polymerizations with equilibrium reactions in the initiation and/or termination step or for the control of the molecular weight distribution (MWD), but it can also be applied to several structural aspects such as stereochemistry, branching, or special technical properties. In the present article, the control of chain growth and chain transfer is discussed. It has been well known for many years that the propagation step in the VC polymerization is terminated to a large degree by the rather frequent and temperature‐dependent chain transfer of the growing macromolecules to the monomer. Therefore, the degree of polymerization is strongly governed by the polymerization temperature. However, this transfer step does not result in a controlled or a narrow MWD. By means of free‐radical nitroxide‐mediated polymerization of VC in suspension, PVC with a narrower MWD can be obtained also at higher polymerization temperatures. The resulting PVC with nitroxide end groups can act as a macro‐initiator for various monomers, resulting in two‐block copolymers, which are, e.g., interesting compatibilizers in blends with PVC. J. VINYL ADDIT. TECHNOL., 11:86–90, 2005. © 2005 Society of Plastics Engineers     

Hemispheric asymmetries in category-specific word retrieval

We examined whether 53 adult non-aphasic patients with either left (22) or right temporal lobe lesions (31) demonstrate dissociable patterns of hemispheric asymmetries in category-specific word fluency tasks. The patients were asked to articulate as many appropriate words as possible within 60 or 90 s in response to six target categories. There was no effect of patient groups on the overall fluency. However, patients with a left-sided temporal lobe lesion were impaired retrieving words to 'initial letters' and to the category 'animals'. Right temporal lobe patients were impaired retrieving 'tools' and words referring to specific visual attributes. There were no fluency differences for 'food-supermarket goods' and 'flat interior'. We conclude that temporal lobe damage can result in category-specific impairments in word retrieval depending on the affected hemisphere.     

Energieoptimierung im vernetzten Eigenheim durch verteilte Wetterdienste im Internet

In this paper we introduce a LonWorks-based heating system which reads the current weather forecast of the Central Institute for Meteorology and Geodynamics (Vienna) from the Internet and, with the help of local weather data, controls the room climate in a way which saves more energy than conventional heatings. Such a heating model needs adequate information processing and controlling structures, which can be realised by concepts of decentralised “intelligence” and by fuzzy control.     

Giant adrenal myelolipomas: CT and MRI findings

A beta (beta/A4) is the major constituent of brain amyloid in Alzheimer's disease (AD), Down's syndrome (DS) and normal aged persons. This protein is presumably derived by normal proteolysis from a precursor protein (APP). In this study, C-terminal fragments of APP in a Tris/Triton soluble fraction were partially purified from DS brain by heparin-affinity and reverse phase chromatography, and analyzed by N-terminal amino acid sequencing after SDS polyacrylamide gel electrophoresis and Western blotting. We found at least six different C-terminal fragments including those with the entire A beta region. These results suggest that secretory processing of APP is heterogeneous and generates amyloidogenic C-terminal fragments.