TY - GEN A1 - Peter, Martin G. T1 - Products of in vitro oxidation of N-acetyldopamine as possible components in the sclerotization of insect cuticle N2 - [1-14C]-N-Acetyldopamine (NADA) was oxidized in the presence of methyl [3-3H]-β-alanate with mushroom tyrosinase. The complex mixture of reaction products was partly resolved by chromatographic procedures and analyzed by spectroscopic methods. Methyl-β-alanate is incorporated to only a small extent into oxidation products of NADA which inter alia are presumed to be oligomeric hydroxyquinones. After oxidation of [1-14C, 2-3H]-NADA with preparations from tanning Manduca sexta pupal cuticle, N-acetylnoradrenalin was identified as one of the products. Binding of radioactivity to melanin-like material was also observed. These results suggest that oxidation products different from those formulated usually for the crosslinkages between protein amino groups and N-acetyldopaquinone are deposited in darkly brown coloured insect cuticles during sclerotization. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 041 KW - N-acetyldopamine KW - sclerotization KW - tyrosinase; o-quinones KW - tanning agents Y1 - 1980 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16759 ER - TY - GEN A1 - Ferenz, Hans-Jürgen A1 - Peter, Martin G. A1 - Berg, Dieter T1 - Inhibition of farnesoic acid methyltransferase by sinefungin N2 - Sinefungin inhibited the S-adenosylmethionine-dependent farnesoic acid methyltransferase in a cell-free system containing a homogenate of corpora allata from female locusts, Locusta migratoria. The enzyme catalyzed the penultimate step of juvenile hormone biosynthesis in the insects. Culturing corpora allata in the presence of sinefungin greatly suppressed juvenile hormone production. The following in vivo effects were visible after injection of the inhibitor: increase in mortality and reduction of total haemolymph protein liter and ovary fresh weight, as well as length of terminal oocytes. Attempts to reverse these effects by topical application of the juvenile hormone analog ZR-515 (methoprene) were only partly successful. Therefore, the in vivo effects may be due to a general inhibition of methyltransferase enzymes in the insect. Sinefungin appeared to be of potential interest as the first representative of a new class of insect growth regulators. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 077 KW - Juvenile hormone analogue KW - Orthoptera KW - Juvenile hormone KW - Biosynthesis KW - Enzyme KW - Corpora allata KW - In vitro KW - Biological activity KW - Enzyme inhibitor Y1 - 1983 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17016 ER - TY - GEN A1 - Kort, C. A. D. de A1 - Peter, Martin G. A1 - Koopmanschap, A. B. T1 - Binding and degradation of juvenile hormone III by haemolymph proteins of the Colorado potato beetle: a re-examination N2 - The haemolymph of the adult Colorado potato beetle, Lepinotarsa decemlineata Say, contains a high molecular weight (MW > 200,000) JH-III specific binding protein. The Kd value of the protein for racemic JH-III is 1.3 ± 0.2 × 10−7 M. It has a lower affinity for racemic JH-I and it does not bind JH-III-diol or JH-III-acid. The binding protein does discriminate between the enantiomers of synthetic, racemic JH-III as was determined by stereochemical anaysis of the bound and the free JH-III. Incubation of racemic JH-III with crude haemolymph results in preferential formation of (10S)-JH-III-acid, the unnatural configuration. The JH-esterase present in L. decemlineata haemolymph is not enantioselective. It is concluded that the most important function of the binding protein is that of a specific carrier, protecting the natural hormone against degradation by esterases. The carrier does not protect JH-I as efficiently as the lower homologue. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 068 KW - Juvenile hormone KW - Leptinotarsa decemlineata KW - JH-III-specific carrier protein KW - enantioselectivity Y1 - 1983 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16777 ER - TY - GEN A1 - Peter, Martin G. A1 - Stupp, Hans-Peter A1 - Lentes, Klaus-Ulrich T1 - Umkehr der Enantioselektivität bei der enzymatischen Hydrolyse von Juvenilhormon als Ergebnis einer Proteinfraktionierung N2 - Aus dem Inhalt: Die Juvenilhormone 1a-c werden im Blut von Insekten enzymatisch zu den biologisch inaktiven Sluren hydrolysiert. Bei der Hydrolyse von racemischem 1c im Blut der Wanderheuschrecke Locusta migratoria wird ein Umsatz von 40-60% erreicht. Das unumgesetzte Edukt enthällt einen Überschuß an natürlich konfiguriertem (10R)-1c (e.e. 47.2%). Wir konnten zeigen, daß das in der Hämolymphe vorhandene Hormon-Bindungsprotein bevorzugt mit (10R)- 1c assoziiert. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 052 Y1 - 1983 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17001 ER - TY - GEN A1 - Laschewsky, André A1 - Ringsdorf, H. A1 - Schmidt, G. T1 - Polymerization of hydrocarbon and fluorocarbon amphiphiles in Langmuir-Blodgett multilayers N2 - Langmuir-Blodgett multilayers of polymerizable carboxylic acids with hydrocarbon or fluorocarbon chains were prepared. The multilayers were polymerized by UV light and the reactions were studied by UV/visible spectroscopy. The polyreactions strongly influence the multilayer structures which were investigated by X-ray small-angle scattering and scanning electron microscopy. The spreading behaviour of the monomers, the preparation of multilayers, their reactivities in multilayers and structural effects caused by the polyreactions are discussed with regard to the hydrophilic head groups, the polymerizable groups and the hydrophobic chains. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 055 Y1 - 1985 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17096 ER - TY - GEN A1 - Elbert, R. A1 - Laschewsky, André A1 - Ringsdorf, H. T1 - Hydrophilic spacer groups in polymerizable lipids: formation of biomembrane models from bulk polymerized lipids N2 - A variety of polymerizable lipids containing a hydrophilic spacer group between the reactive group and the main amphiphilic structure have been synthesized. They were investigated in monolayers, liposomes, and multilayers. When the spacer concept was used, efficient decoupling of the motions of the polymeric chain and the amphiphilic side groups is achieved. Thus, the often found loss of the important fluid phases by polymerization is avoided. Polymeric monolayers of the spacer lipid, prepared either by polymerization in the monolayer or by spreading of prepolymerized lipid, exhibit nearly identical surface pressure-area diagrams. Most distinctly, the successful decoupling of the motions of the polymer main chain and the membrane forming amphiphilic side groups is demonstrated by the self-organization of bulk polymerized spacer lipids to polymeric liposomes. In addition, spacer lipids are able to build polymeric Langmuir-Blodgett multilayers. The decoupling of the polymer main chain and the membrane-forming amphiphilic side groups enables the deposition of already polymeric monolayers onto supports to form defined multilayers. If, alternatively, monomeric monolayers are deposited and polymerized on the support, defects in the layers due to structural changes during the polymerization are avoided by the flexible spacer group. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 095 Y1 - 1985 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17361 ER - TY - GEN A1 - Koch, Horst A1 - Laschewsky, André A1 - Ringsdorf, Helmut A1 - Teng, Kang T1 - Photodimerization and photopolymerization of amphiphilic cinnamic acid derivatives in oriented monolayers, vesicles and solution N2 - Cinnamic acid moieties were incorporated into amphiphilic compounds containing one and two alkyl chains. These lipid-like compounds with photoreactive units undergo self-organization to form monolayers at the gas-water interface and bilayer structures (vesicles) in aqueous solutions. The photoreaction of the cinnamic acid moiety induced by 254 nm UV light was investigated in the crystalline state, in monolayers, in vesicles and in solution in organic solvents. The single-chain amphiphiles undergo dimerization to yield photoproducts with twice the molecular weight of the corresponding monomers in organized systems. The photoreaction of amphiphiles containing two cinnamic acid groups occurs via two mechanisms: The intramolecular dimerization produces bicycles, with retention of the molecular weight of the corresponding monomer. The intermolecular reaction leads to oligomeric and polymeric photoproducts. In contrast to the single-chain amphiphiles, photodimerization processes of lipoids containing two cinnamic acid moieties also occur in solution in organic solvents. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 078 Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17111 ER - TY - GEN A1 - Albrecht, O. A1 - Cumming, W. A1 - Kreuder, W. A1 - Laschewsky, André A1 - Ringsdorf, Helmut T1 - Monolayers of rod-shaped and disc-shaped liquid crystalline compounds at the air-water interface N2 - Calamitic (rod-shaped) and discotic (disc-shaped) thermotropic liquid crystalline (LC) compounds were spread at the air-water interface, and their ability to form monolayers was studied. The calamitic LCs investigated were found to form monolayers which behave analogously to conventional amphiphiles such as fatty acids. The spreading of the discotic LCs produced monolayers as well, but with a behaviour different from classical amphiphiles. The areas occupied per molecule are too small to allow the contact of all hydrophilic groups with the water surface and the packing of all hydrophobic chains. Various molecular arrangements of the discotics at the water surface to fit the spreading data are discussed. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 079 KW - Monolayers KW - liquid crystals KW - discotics Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17124 ER - TY - GEN A1 - Laschewsky, André A1 - Ringsdorf, H. A1 - Schneider, J. T1 - Oriented supramolecular systems-polymeric monolayers and multilayers from prepolymerized amphiphiles N2 - Oriented polymeric membranes were originally prepared by polymerization or polycondensation of preoriented monomers. The introduction of hydrophilic spacer groups into the polymeric amphiphiles allowed the formation of highly ordered systems (monolayers, liposomes, multilayers) from prepolymerized amphiphiles: due to the partial decoupling of the different mobilities and orientation tendencies of the polymer chain and the amphiphilic side groups, these polymers are able to self-organize. In monolayer experiments the high order of these membranes could be demonstrated by their surface pressure area-diagrams. In addition the combination of order and mobility of these spacer groups containing polymeric amphiphiles allowed the formation of Langmuir-Blodgett-multilyers with a high layer correlation. Thus, disturbancies in highly oriented layers can be avoided normally taking place during the polymerization reaction (e.g. contractions) or oriented monomeric layers. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 056 Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17131 ER - TY - GEN A1 - Laschewsky, André A1 - Ringsdorf, H. A1 - Schmidt, G. A1 - Schneider, J. T1 - Self-organization of polymeric lipids with hydrophilic spacers in side groups and main chain : investigation in monolayers and multilayers N2 - Several polymerizable lipids were synthesized and polymerized to amphiphilic homopolymers and to copolymers with the help of hydrophilic comonomers. The self-organization of these polymeric lipids was investigated in monolayers and Langmuir-Blodgett multilayers. The self-organization of these polymers in model membranes is due to hydrophilic spacer groups in the amphiphilic side groups as well as to hydrophilic spacer groups in the polymer backbone. Thus, highly ordered monolayers and LB-multilayers are easily obtained. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 057 Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17147 ER - TY - GEN A1 - Ferenz, Hans-Jörg A1 - Peter, Martin G. T1 - The inhibitory effect of sinefungin on juvenile hormone biosynthesis and development in locusts N2 - The antibiotic fungal metabolite sinefungin is a potent inhibitor of S-adenosylmethionine-acceptor methyltransferases. Its effect on insect metabolism and especially on corpora allata farnesoic acid methyltransferase, which catalyzes the penultimate step of juvenile hormone biosynthesis, was investigated in Locusta migratoria. Injection of sinefungin results in a delay of imaginal molt and in suppression of ovary development. Isolated corpora allata are unable to synthesize juvenile hormone III in the presence of more than 1.0 mM sinefungin. In a cell-free system containing the S-adenosylmethionine-dependent farnesoic acid methyltransferase from corpora allata sinefungin is a competitive inhibitor of the synthesis of methylfarnesoate with Ki of 1 μM. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 076 KW - Locust KW - sinefungin KW - O-methyltransferase KW - juvenile hormone biosynthesis Y1 - 1987 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16811 ER - TY - GEN A1 - Laschewsky, André A1 - Ringsdorf, H. T1 - Polymerization of amphiphilic dienes in Langmuir-Blodgett multilayers N2 - Amphiphilic derivatives of octadiene and docosadiene were investigated in monolayers and Langmuir-Blodgett multilayers, with respect to their self-organization and their polymerization behavior. All amphiphiles investigated form monolayers. However, only acid and alcohol derivatives were able to build up multilayers. Those multilayers are rapidly photopolymerized in the layers via a two-step process: Irradiation with long-wavelength UV light yields soluble polymers, whereas additional irradiation with sfiort-wavelength UV light produces insoluble and presumably cross-linked polymers. The reaction meclianism is discussed according to the polymer characterization by UV spectroscopy, small-angle X-ray scattering, NMR spectroscopy, and gel permeation chromatography. All multilayers undergo structural changes during the polymerization; substantial changes result in defects in the polymerized layers as observed by scanning electron microscopy. In contrast to the acids and alcohols, the deposition of monolayers of the aldehyde derivatives did not yield well-ordered multilayers, but rather amorphous films. In this different film structure, the photopolymerization process differs from the one observed in multilayers. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 058 Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17176 ER - TY - GEN A1 - Lupo, Donald A1 - Prass, Werner A1 - Scheunemann, Ude A1 - Laschewsky, André A1 - Ringsdorf, Helmut A1 - Ledoux, Isabelle T1 - Second-harmonic generation in Langmuir-Blodgett monolayers of stilbazium salt and phenylhydrazone dyes N2 - Contents: 1. INTRODUCTION 2. SYNTHESIS OF THE COMPOUNDS 3. PREPARATION AND CHARACTERIZATION OF MONOLAYERS A. Monolayer Isotherms B. Langmuir-Blodgett Monolayer Films 4. EXPERIMENTAL SETUP FOR NONLINEAR MEASUREMENTS 5. NONLINEAR OPTICAL PROPERTIES 6. DISCUSSION 7. CONCLUSION T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 094 Y1 - 1988 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17401 ER - TY - GEN A1 - Peter, Martin G. A1 - Förster, Hans T1 - On the structure of Eumelanins : identification of constitutional patterns by solid-state NMR spectroscopy N2 - Aus dem Inhalt: Melanins are complex polyphenolic polymers. They are usually formed in nature by enzyme-catalyzed oxidative polymerization of o-diphenols. The deep black eumelanins, derived from Dopa 1 or dopamine 3, are distinguished from the yellow to brown phaeomelanins obtained from Dopa in the presence of cysteine. Characteristic of eumelanins are the indole units, which are formed from catecholamines by intramolecular addition of the amino groups to the oxidatively generated o-quinones. [...] T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 053 Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17027 ER - TY - GEN A1 - Erdelen, C. A1 - Laschewsky, André A1 - Ringsdorf, H. A1 - Schneider, J. A1 - Schuster, A. T1 - Thermal behaviour of polymeric Langmuir-Blodgett multilayers N2 - Langmuir-Blodgett multilayers of hydrocarbon and fluorocarbon polymers with hydrophilic spacer, lipid-polyelectrolyte complexes and mesogenic polymers have been prepared. The thermal behaviour of the multilayers was studied by small angle X-ray scattering, IR and UV—visible spectroscopy. Good thermal stabilities were found for the various classes of polymers. In addition, for both complexed multilayers and mesogenic polymer films, reorientation processes were observed. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 080 Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17378 ER - TY - GEN A1 - Peter, Martin G. T1 - Chemische Modifikation von Biopolymeren durch Chinone und Chinonmethide N2 - Chinone und Vorstufen, die oxidativ in Chinone und/oder Chinonmethide umgewandelt werden können, sind in der Natur weit verbreitet. Als sekundäre Naturstoffe wirken sie häufig antibiotisch, cytotoxisch, aber auch pathogen, und eine Reihe von Pflanzen und Tieren benutzt chinoide Substanzen als Abwehrstoffe, oft mit spektakulärem Erfolg. Auf makromolekularer Ebene spielen Chinonmethide im Pflanzenreich eine Schlüsselrolle bei der Biosynthese von Lignin, während die Bildung von Melanoproteinen ein Beispiel für Reaktionen von o-Chinonen im Tierreich ist. Bei den Insekten dienen Chinone und Chinonmethide zur Bildung des lebensnotwendigen Exoskeletts. Die Reaktivität von Chinonen in biologischen Systemen hat auch für den Menschen unmittelbare Bedeutung in pharmazeutischer, toxikologischer und technologischer Hinsicht. Den Beispielen in diesem Aufsatz liegt ein gemeinsames Prinzip zugrunde, nämlich die chemische Modifikation von Biopolymeren durch Chinone und Chinonmethide. Wie sich besonders bei einer detaillierteren Betrachtung der Reaktionen zeigt, die zur Sklerotisierung der Insektencuticula führen, sind in den letzten Jahren wichtige neue Erkenntnisse hinzugekommen, die vor allem durch die modernen Methoden der Stofftrennung und der Festkörper-NMR-Spektroskopie ermöglicht worden sind. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 043 Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16802 ER - TY - GEN A1 - Laschewsky, André T1 - Monolayers and Langmuir-Blodgett multilayers of discotic liquid crystals? N2 - Contents: 1. Discotic Liquid Crystals 2. Monolayers and Langmuir-Blodgett Multilayers 3. Theoretical Considerations on the Molecular Packing of Discotic LCs in Monolayers and Multilayers 4. Spreading Experiments with Discotic LCs 5. LB-Multilayers of Discotic LCs 6. Polymeric Discotic LCs 7. Summary T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 061 Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17396 ER - TY - GEN A1 - Biddle, M. B. A1 - Rickert, S. E. A1 - Lando, J. B. A1 - Laschewsky, André T1 - The use of the Langmuir-Blodgett technique to obtain ultra-thin polar films N2 - The piezoelectric and pyroelectric properties of oriented films possessing dipole moments are increasingly being used in pressure, acoustic, thermal and optical devices. The performance of these devices in many applications may be enhanced by thin-film technology.The developing Langmuir-Blodgett thin-film deposition technique offers the opportunity to obtain highly oriented and uniform organic-based films in the 10–5000 nm thickness range. Special techniques must be used, however, to assemble these molecules in such a way as to result in polar multilayer films. Several possible deposition techniques are investigated, with one resulting in a polar and pyroelectric film about 50 nm thick. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 098 Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17185 ER - TY - GEN A1 - Peter, Martin G. A1 - Förster, Hans T1 - Zur Struktur von Eumelaninen : Identifizierung von Konstitutionsmustern durch Festkörper-NMR-Spektroskopie T1 - On the Structure of Eumelanins : Identification of Constitutional Patterns by Solid-state NMR Spectroscopy N2 - Aus dem Inhalt: Melanine sind komplexe polyphenolische Polymere. In der Natur entstehen sie durch meist enzymkatalysierte oxidative Polymerisation von o-Diphenolen. Man unterscheidet die aus Dopa 1 oder Dopamin 3 hervorgehenden, tiefschwarzen Eumelanine von den aus Dopa in Gegenwart von Cystein entstehenden, gelben bis braunen Phaomelaninen. [...] T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 054 Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17038 ER - TY - GEN A1 - Peter, Martin G. A1 - Boldt, Peter C. A1 - Niederstein, Yvonne A1 - Peter-Katalinić, Jasna T1 - Synthesen von Galactose-Cluster-haltigen Steroid-Derivaten N2 - The synthesis of galactose clusters that are linked to a steroid moiety by a peptide-like spacer unit is described. The galactose cluster is obtained by Koenigs-Knorr glycosylation of TRIS-Gly-Fmoc (2b) under Helferich conditions. Peptide and ester bonds are formed after activation of carboxylic acids as diphenylthiophene dioxide (TDO) esters. 6a is synthesized in a convergent way by coupling of (Ac4Gal)3-TRIS-Gly (3e) with cholesteryl TDO succinate (5b). Coupling of (Ac4Gal)3-TRIS-Gly hydrogen succinate (3f) with Gly-O-Chol (5d) by means of EEDQ yields 6d. Reaction of (Ac4Gal)3-TRIS-Gly-SUCC-O-TDO (3g) with 25-hydroxycholesterol leads in a linear sequence to the oxysterol derivative 6f. Selective cleavage of the acetyl groups from galactose units yields the known compound 6b and the new derivatives 6e and 6g. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 042 KW - Glycoconjugates KW - Galactosides KW - Steroid esters KW - Amphiphiles KW - Glycopeptides Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16783 ER - TY - GEN A1 - Embs, Frank A1 - Funhoff, Dirk A1 - Laschewsky, André A1 - Licht, Ulrike A1 - Ohst, Holger A1 - Prass, Werner A1 - Ringsdorf, Helmut A1 - Wegner, Gerhard A1 - Wehrmann, Rolf T1 - Preformed polymers for Langmuir-Blodgett films- molecular concepts N2 - The use of preformed polymers for the preparation of Langmuir-Blodgett (LB) multilayers is reviewed. Principles for polymer self-organization are outlined and the appropriate molecular designs are discussed. Recent developments in the different classes of polymers for LB multilayers are presented, and their outstanding properties highlighted. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 081 KW - Amphiphilic Polymers KW - Rod-like Polymers KW - LCPs KW - Stability of LB Films Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17196 ER - TY - BOOK ED - Zülicke, Lutz T1 - Chemical Physics Y1 - 1991 PB - Elsevier CY - Amsterdam [u.a.] ER - TY - JOUR A1 - Schröder, Martina A1 - Kümmel, Rolf A1 - Mickler, Wulfhard A1 - Uhlemann, Erhard T1 - Zur Abtrennung von Kupfer aus ammoniakalischer Lösung durch Flüssig-Flüssig-Extraktion und Flüssigmembranpermeation mit 1-Phenyl-3-methyl-4-stearoylpyrazol-5-on Y1 - 1991 ER - TY - JOUR A1 - Kempter, Gerhard A1 - Sarodnick, Gerhard T1 - Synthese von Pyrazolyl- und Pyrimidinylchinoxalinen Y1 - 1991 ER - TY - BOOK A1 - Kempter, Gerhard T1 - Organisch-chemisches Praktikum T3 - Studienbücherei : Chemie für Lehrer Y1 - 1991 VL - 1 PB - Dt. Verl. d. Wiss. CY - Berlin ER - TY - BOOK A1 - Kempter, Gerhard A1 - Jumar, Alfred T1 - Chemie organischer Pflanzenschutz- und Schädlingsbekämpfungsmittel Y1 - 1991 PB - Dt. Verl. d. Wiss. CY - Berlin ER - TY - GEN A1 - Anton, Peter A1 - Laschewsky, André T1 - Polysoaps via alternating olefin/SO2 copolymers N2 - Contents: Introduction Results and discussion - Monomers studied - Monomer properties - Polymerization, copolymer composition and general properties - Polymer properties in aqueous solution Conclusion Experimental part - Materials - Copolymerization with S02 (typical procedure) - Methods T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 088 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17216 ER - TY - GEN A1 - Laschewsky, André T1 - Oligoethyleneoxide spacer groups in polymerizable surfactants N2 - Cationic and zwitterionic polymerizable surfactants bearing tri- and tetraethyleneglycol spacer groups between the polymerizable moiety and the surfactant structure were prepared and polymerized. Monomers and polymers were investigated with respect to their aggregation behavior in aqueous systems and compared to analogous monomers and polymers lacking spacer groups. In the case of the monomeric surfactants, the spacer groups depress both the Kraffttemperature and the critical micelle concentration. the area occupied per molecule at the air-water interface is substantially enlarged by the spacers, whereas the depression of surface tension is nearly constant. Although the monomers with and without spacers are true surfactants, all the polymers are water-insoluble, but form monomolecular layers at the air-water interface. In analogy to the monomer behavior, the incorporation of the spacer groups increases the area occupied per repeat unit at the air-water interface substantially, but hardly affects the surface activity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 059 KW - Polymerizable surfactant KW - polysoap KW - sulfobetain KW - spacer KW - micelle KW - monolayer Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17221 ER - TY - GEN A1 - Bubeck, Christoph A1 - Laschewsky, André A1 - Lupo, Donald A1 - Neher, Dieter A1 - Ottenbreit, Petra A1 - Paulus, Wolfgang A1 - Prass, Werner A1 - Ringsdorf, Helmut A1 - Wegner, Gerhard T1 - Amphiphilic dyes for nonlinear optics: Dependence of second harmonic generation on functional group substitution T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 082 Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17201 ER - TY - GEN A1 - Köberle, Peter A1 - Laschewsky, André A1 - Tsukruk, Vladimir T1 - The structural order of some novel ionic polymers : 1. X-ray scattering studies N2 - A set of novel zwitterionic side-chain polyacrylates and polymethacrylates is studied by X-ray scattering. The structural order both in the short-range and long-range scale is investigated. The influence of the polymer backbone, of different locations of the ionic groups in isomeric polymers, of bound water and of added inorganic salts on the bulk structures is studied, and the observed rearrangements are analysed. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 089 Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17247 ER - TY - BOOK A1 - Kleinpeter, Erich T1 - NMR-Spektoskopie : Struktur, Dynamik und Chemie des Moleküls Y1 - 1992 PB - Barth CY - Leipzig ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Dargatz, M. T1 - Eine 2D-INEPT-Variante zur Detektierung wenig empfindlicher Kerne Y1 - 1992 ER - TY - JOUR A1 - Arrieta, A. A1 - Beyer, L. A1 - Lehmann, J. A1 - Dargatz, M. A1 - Kleinpeter, Erich T1 - Synthese und 1H-NMR-spektroskopische Untersuchungen neuer Curcuminanaloga Y1 - 1992 ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Stohß, S. A1 - Schroth, W. T1 - Stereochemistry and complexational behaviour of dibenzo-crown ethers Y1 - 1992 ER - TY - JOUR A1 - Griel, C. A1 - Ströhl, D. A1 - Jeschkeit, H. A1 - Kleinpeter, Erich T1 - Synthetische und NMR-spektroskopische Untersuchungen der Benzzyl-aminaddition an N-Maleyl- aminosäurederivaten Y1 - 1992 ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Hartmann, Jürgen A1 - Schroth, W. A1 - Hofer, O. A1 - Kalchhauser, H. A1 - Wurz, G. T1 - Synthesis and conformational behaviour of Ditosyldiaza[2.2]orthometacyclophanes Y1 - 1992 ER - TY - JOUR A1 - Ströhl, D. A1 - Thomas, Steffen A1 - Radeglia, R. A1 - Brunn, J. A1 - Kleinpeter, Erich T1 - 13C-NMR-Untersuchungen von Substituenteneffekten in mehrfach substituierten Benz-und Naphthalenderivaten ; Inkrementberechnungen der 13C-chemischen Verschiebungen Y1 - 1992 ER - TY - THES A1 - Schilde, Carolin T1 - Beiträge zur physikalisch-chemischen Charakterisierung und quantitativen Struktur-Wirkungsanalyse von potentiellen Azneimitteln Y1 - 1992 ER - TY - THES A1 - Schilde, Uwe T1 - Zur Abtrennung von Oxoanionen mittels chelatbildender Ionenaustauscher Y1 - 1992 ER - TY - THES A1 - Hainich, Kerstin T1 - Verwendung von Metallen unter ökologischen Gesichtspunkten - Materialien für den Chemieunterricht und Bereitstellung fachwissenschaftlicher (chemischer) Kenntnisse Y1 - 1992 ER - TY - JOUR A1 - Herzschuh, R. A1 - Wenzlawiak, B. A1 - Plaggenborg, L. A1 - Mickler, Wulfhard A1 - Uhlemann, Erhard T1 - The characterization of the active components in commercial ß-diketone-type extractants LIX 54 and MX 80 A Y1 - 1992 ER - TY - JOUR A1 - Mickler, Wulfhard A1 - Uhlemann, Erhard T1 - Liquid-Liquid-Extraktion of copper from ammoniacal solutions with ß-diketones Y1 - 1992 ER - TY - JOUR A1 - Mickler, Wulfhard A1 - Uhlemann, Erhard A1 - Herzschuh, R. T1 - Nebenprodukte bei klassischen ß-Diketon-Synthesen Y1 - 1992 ER - TY - GEN A1 - Peter, Martin G. A1 - Andersen, Svend Olav A1 - Hartmann, Rudolf A1 - Miessner, Merle A1 - Roepstorff, Peter T1 - Catecholamine-protein conjugates : isolation of 4-phenylphenoxazin-2-ones from oxidative coupling of N-acetyldopamine with alipathic amino acids N2 - 4-Phenylphenoxazinones were isolated after biomimetic oxidation, using diphenoloxidases of insect cuticle, mushroom tyrosinase, or after autoxidation of N-acetyldopamine (Image ) in the presence of β-alanine, β-alanine methyl ester or N-acetyl-L-lysine. They are formed presumably by addition of 2-aminoalkyl-5-alkylphenols to the o-quinone of biphenyltetrol which, in turn, arises from oxidative coupling of. The structures of present the first examples for the assembly of reasonably stable intermediates in the rather complex process of chemical modifications of aliphatic amino acid residues by o-quinones. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 062 Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17571 ER - TY - GEN A1 - Laschewsky, André A1 - Paulus, Wolfgang A1 - Ringsdorf, Helmut A1 - Schuster, A. A1 - Frick, G. A1 - Mathy, A. T1 - Mixed polymeric monolayers and Langmuir-Blodgett multilayers with functional low molecular weight guest compounds N2 - Mixed monolayers and Langmuir-Blodgett multilayers of functional low molecular weight guest compounds, especially nonlinear optical (NLO) dyes, within the matrix of an amphotropic spacer polymer have been prepared. The polymer matrix enabled the transfer of guest compounds not capable of self-organizing at the air-water interface by themselves. The structure of the LB multilayers and the transfer process were studied by small angle X-ray scattering and UV-visible spectroscopy. Good NLO coefficients were found in the mixed films. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 060 Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17233 ER - TY - GEN A1 - Andersen, Svend Olav A1 - Perter, Martin G. A1 - Roepstorff, Peter T1 - Cuticle-catalyzed coupling between N-acetylhistidine and N-acetyldopamine N2 - Several types of insect cuticle contain enzymes catalyzing the formation ofof adducts between N-acetyldopamine (NADA) and N-acetylhistidine (NAH). Two such adducts, NAH-NADA-I and NAH NADA-II, have been isolated and their structures determined. In one of the adducts the link connecting the two residues occurs between the I-position (ß-position) in the NADA side chain and the 1-N atom (τ-N) in the imidazole ring of histidine. Diphenoloxidase activity alone is not sufficient for formation of this adduct, whereas extracts containing both diphenoloxidase and o-quinone-p-quinone methide isomerase activities catalyze the coupling reaction. The adduct consists of a mixture of two diastereomers and they are presumably formed by spontaneous reaction between enzymatically produced NADA-p-quinone methide and N-acetylhistidine. The other adduct has been identified as a ring addition product of N-acetylhistidine and NADA. In contrast to the former adduct it can be formed by incubation of the two substrates with mushroom tyrosinase alone. An adduct between N-acetylhistidine and the benzodioxan-type NADA-dimer is produced in vitro, when the N-acetylhistidine-NADA adduct is incubated with NADA and locust cuticle containing a 1,2-dehydro-NADA generating enzyme system. Trimeric NADA-polymerization products of the substituted benzodioxan-type have been obtained from in vivo sclerotized locust cuticle, confirming the ability of cuticle to produce NADA-oligomers. The results indicate that some insect cuticles contain enzymes promoting linkage of oxidized NADA to histidine residues. It is suggested that histidine residues in the cuticular proteins can serve as acceptors for oxidized NADA and that further addition of NADA-residues to the phenolic groups of bound NADA can occur, resulting in formation of protein-linked NADA-oligomers. The coupling reactions identified may be an important step in natural cuticular sclerotization. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 072 KW - sclerotization KW - quinone KW - quinone methide KW - o-quinone isomerase KW - Hyalophora cecropia KW - Locusta migratoria Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16762 ER - TY - GEN A1 - Tsukruk, Vladimir A1 - Mischenko, Nikolay A1 - Köberle, Peter A1 - Laschewsky, André T1 - The structural order of some novel ionic polymers; 2. : Models of molecular packing N2 - The molecular packing and spatial correlations of two isomeric zwitterionic polymethacrylates and one polyacrylate analog are studied by means of X-ray analysis and conformational calculations. The analysis of the correlation functions and density distribution profiles suggest a double-layered molecular packing which is discussed for the three polymers investigated, with respect to their different chemical structures. Whereas the zwitterionic polymethacrylates studied exhibit liquid-like short-range order, the polyacrylate analog exhibits an ordered double-layered superstructure. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 096 Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17256 ER - TY - GEN A1 - Anton, Peter A1 - Laschewsky, André T1 - Zwitterionic polysoaps with reduced density of surfactant side groups N2 - Several zwitterionic polymers were prepared by radical homopolymerization of surfactant monomers which bear diallyl, diene or vinylcyclopropane moieties. These polymer systems were complemented by alternating copolymers of appropriate zwitterionic vinyl compounds. Thus, polymers with reduced (as compared with simple vinylic homopolymers, or statistical copolymers) and well defined density of surfactant side groups are obtained. The solubilities found for these polymers are dominated by polymer geometry rather than by the balance of hydrophilic and hydrophobic fragments, thus corroborating a main-chain spacer model proposed recently. All water-soluble polymers exhibit characteristic features of classical polysoaps, as shown by surface tension measurements and by solubilization of hydrophobic dyes. In contrast, the water-insoluble copolymers are capable to form stable monolayers at the air-water interface. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 091 Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17301 ER - TY - THES A1 - Nehls, Irene T1 - 13C-NMR-spektroskopische Untersuchungen von Cellulose und Cellulosedervitaten in Lösung BT - Dreizehn-C-NMR-spektroskopische Untersuchungen von Cellulose und Cellulosedervitaten in Lösung Y1 - 1993 ER - TY - JOUR A1 - Haufe, G. A1 - Rolle, U. A1 - Kleinpeter, Erich A1 - Kivikoski, J. A1 - Rissanen, K. T1 - N-Heterocyclization in electrophilic haloamination reactions of 1,5-cyclooctadiene : formation of the granatanine and homotropane skeletons Y1 - 1993 ER -