Search results for "Mono"

Dihydrodiol Dehydrogenase: Substrate Specificity, Inducibility and Tissue Distribution

1982

The present study shows that: Dihydrodiol dehydrogenase activity is present in the 100,000 g supernatant fraction of extrahepatic tissues. Dihydrodiol dehydrogenase is able to oxidize the hydroxy group and to reduce the keto group of a number of xenobiotics including quinones derived from polycyclic aromatic hydrocarbons. Dihydrodiol dehydrogenase was not inducible by various substances including hormones, polycyclic aromatic hydrocarbons, substrates of the enzyme and potent inducers of monooxygenases, epoxide hydrolase and glutathione S-transferases. Only in the case of thyroxine was a weak induction with a high dose of the hormone observed.

X-Ray Scattering Studies of Organic Monolayers on Electrolytic Solutions: Arachidic Acid on CdCl2

1992

The interaction between a charged monolayer of fatty acid molecules on the surface of a CdCl2 aqueous solution and the ions below has been investigated by means of X-ray Reflection and Grazing-Incidence Diffraction. A stoichiometric, localised layer of Cd++ ions forms an epitaxial 2×3 superstructure below the 2D-crystalline fatty acid monolayer.

Second-order NLO main-chain polymers by polymerization of poled monomers

1993

A new method of preparing oriented NLO main chain polymers is presented. We synthesized NLO-monomers that consist of donor acceptor substituted tolane molecules that can be poled in the low molar mass state. In the oriented polar state these monomers can be chemically linked using a thermally activated polyaddition reaction. This reaction links the donor head of one monomer to the acceptor tail of the next hibiting bulk noncentrosymmetry with the average direction of the molecular dipoles parallel to the aligning field.

1979

The thermal degradation behavior of head-to-head (H-H) and head-to-tail (H-T) polystyrenes and poly(vinylcyclohexane)s has been investigated by direct pyrolysis in a mass spectrometer. Both H-H and H-T isomers show only small differences in their initial temperatures of decomposition but remarkably different degradation processes. Whereas H-T polystyrene decomposes in accordance with earlier investigations mainly by a radicalic depolymerization into the monomer and yields only a small amount of dimer and trimer, the H-H polystyrene shows no unzipping and only a statistic degradation into oligomeric styrenes. The formation of stilbene is a diagnostic reaction of H-H polystyrene. The pyrolysi…

Defect-Free Chemical Functionalization of Magnetic Monolayers Based on Coordination Polymers

2018

<p>Chemical functionalization has demonstrated to be a powerful approach to tailor the physical and chemical properties of two-dimensional (2D) materials, to increase their processability and</p> <p>stability, to add new functionalities and, even, to create new 2D materials. However, this post synthetic method – which involves the anchoring of molecules on the surface of an exfoliated 2D crystal – inevitably leads to defective materials, which lack long-range structural order. If defect-free functionalized monolayers are required, a radically new approach needs to be developed. Here we present a pre-synthetic method based on coordination chemistry that affords the isolatio…

Electrochemical production of initiators for polymerization processes

2007

The most important technological interest in initiator production lies, in the electrosynthesis of complex catalytic systems, i. e. coordination compounds and Ziegler-Natta catalysts, although the choice of olefins to be polymerized with these electrosynthesized complexes is still limited to ethylene and to very few other monomers.

Die Redox-Polymerisation des Acroleins in wäßrigem Medium. Polymere acroleine. 6. Mitteilung

1957

Die Polymerisation wasriger Acrolein-Losungen mit Hilfe von Redox-Systemen wird untersucht. Es wird der Einflus der Temperatur, der Monomeren-und der Initiator-Konzentration beschrieben. Die Charakterisierung der Polymerisate erfolgt durch Bestimmung des Aldehydgruppengehaltes und der spezifischen Viskositat in wasriger Schwefeldioxyd- Losung. Die hier beschriebene Polymerisation des Acroleins hat die Merkmale der radikalischen Vinylpolymerisation. The polymerisation of aqueous solution of acrolein by the action of redox-systems has been investigated. The influence of the temperature and the concentration of the initiator and of the monomer is described. The polymers are characterized by th…

Untersuchungen über die radikalpolymerisation von acrylamid

1954

Verschiedene Methoden zur Radikal-Polymerisation von Acrylamid mit und ohne Losungsmittel werden beschrieben. Die durch γ-Strahlen ausgeloste Polymerisation ergibt sehr hochmolekulare Polymerisate; dagegen haben die mittels Fenton-Reagens erhaltenen Produkte nur sehr geringe spezifische Viskositat. Ultraschall wirkt auf das Monomere polymerisierend und auf das Polymere depolymerisierend. Aus den Viskositatskurven eines reinen Polymerisates und seiner Fraktionen ist zu schliesen, das solche Polyacrylamide in wasriger Losung als homoopolare Molekulkolloide vorliegen. Different methods of radical-polymerization of acrylamide in solution and in bulk are described. The γ-rays induced polymerizat…

1972

The determination of reactivity ratios is simplified by using an excess of one monomer (M1) at a time large enough that the copolymers will have a very small content of the other monomer (M2). In this case chain propagation takes place almost exclusively by addition to polymer radicals with a terminal M1-unit (P) and monomer consumption by propagation of P may be neglected. One reactivity ratio (r1) is obtained from monomer conversions by means of a simple integrated equation which is valid up to high conversions. A calculation is proposed in order to account for the neglected propagation via P. The other reactivity ratio (r2) is obtained from copolymerizations with excess M2. As the new me…

Fractionation

2012

The enormous diversity of polymers with respect to molecular weight, molecular architecture, and – in the case of copolymers – also the content and arrangement of dissimilar monomers requires well-targeted methods for the separation of the different species that are contained in a given sample. This chapter presents the most abundant fractionation procedures, which are either based on thermodynamic driving forces (like in the case of liquid–liquid phase separation) or on kinetic effects (as with field-flow fractionation).