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  • Organic Chemistry  (27)
  • Polymer and Materials Science  (23)
  • D600  (3)
  • 1
    Electronic Resource
    Electronic Resource
    D600 prolongs inactivation of the contractile system in frog twitch fibres (1987)
    Springer
    Pflügers Archiv 410 (1987), S. 75-82 
    Details
    ISSN: 1432-2013
    Keywords: Twitch fibre ; K-contracture ; Inactivation ; D600
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract (1) Single twitch fibres were dissected from tibialis muscles ofRana temporaria and used to study the effect of D600 (gallopamil) on potassium-induced contractures. (2) 95 mM K-Ringer's was applied for 8–15 s at intervals of generally 2.5–5 min; at temperatures of 6–8°C and in the absence of D600 the amplitude of the contractures remained fairly constant. After pretreatment with D600 (30 μM) a single (conditioning) K-contracture was sufficient to ‘paralyze’ the fibres (cf. Eisenberg et al. 1983). (3) Complete paralysis could also be achieved at 18–20°C. In three fibres a single conditioning K-application was sufficient; in two more fibres two or three conditioning K-applications were required. (4) D600-paralysis could not only be achieved with high K-concentrations but also by conditioning with subor suprathreshold K-concentrations (20–40 mM); the duration of the conditioning periods required to induce complete paralysis was approximately the same before and after D600-treatment. (5) Contractures were partially abolished by application of 20–40 mM K-Ringer's for short conditioning periods; after D600-treatment the degree of contracture loss was similar. (6) At low temperature the state of partial or complete paralysis induced by subthreshold K-concentrations and D600 was maintained for long periods of time. (7) The presence of 10 mM Ca2+ did not protect the fibres from being paralyzed by treatment with D600 and high K-Ringer's at low temperature; however, more than one conditioning K-application was required. (8) Resting and action potentials of paralyzed fibres were not significantly different from control values. However, endplate potentials were reduced in size, and failure of neuromuscular transmission was observed in some of these fibres. (9) It is concluded that D600 prolongs the state of inactivation of the contractile mechanism, while the development of inactivation does not seem to be markedly affected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00581899
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of D600 on potassium contractures of slow muscle fibres ofRana temporaria (1988)
    Springer
    Pflügers Archiv 412 (1988), S. 390-396 
    Details
    ISSN: 1432-2013
    Keywords: Slow fibre ; K-Contracture ; D600 ; Inactivation ; Repriming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract (1) The effect of 30 μM D600 on the amplitude and time course of isometric contractures was studied in single slow fibres ofRana temporaria. (2) D600 only slightly reduced the amplitude of contractures evoked with 30 or 95 mM K-Ringer's. Maintenance of tension was strongly impaired by D600 only during exposure to 95 mM K. The caffeine contracture was not affected. (3) Addition of 10 mM Ca2+ or other divalent cations to the medium strongly counteracted the effect of D600 on maintained tension. The order of efficiency was Ca2+=Ni2+〉Co2+〉Mn2+〉Mg2+. (4) During 2 min exposure to 95 mM K-Ringer's the slow fibres inactivated to a variable degree; recovery from inactivation in normal Ringer's proceeded with a half time of the order of 1 min, while in the presence of D600 recovery was prolonged 3.3 to 27 times. (5) It is concluded that the effect of D600 on the contractile behaviour of slow fibres fromRana temporaria is predominantly due to a prolongation of the inactivated state. It is suggested that D600 binds to a site at the outer membrane surface which also binds divalent cations and determines the degree of contractile inactivation during exposure to potassium. Blocking of Ca2+ channels is unlikely to be the mechanism of this D600-effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01907557
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  • 3
    Electronic Resource
    Electronic Resource
    Competitive action of divalent cations and D600 in frog slow muscle fibers (1989)
    Springer
    The journal of membrane biology 112 (1989), S. 185-192 
    Details
    ISSN: 1432-1424
    Keywords: slow fiber ; K contracture ; D600 ; divalent cations ; competitive binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Single, slow muscle fibers fromRana temporaria were equilibrated in normal Ringer's. 95 mmol/liter K1-solution containing various concentrations of Ca2+, Ni2+, Mn2 or Mg2+ was applied, and the ensuing contractures were recorded isometrically. While peak tension (F max) was little affected, maintained tension (measured 1 min after onset of contracture) strongly depended on the concentration and species of divalent cations. Tension was maintained at its peak value in the presence of all species of divalent cations provided their concentrations were adequately increased. Dose-response curves were hyperbolic: Lineweaver-Burk plots revealed straight lines with different slopes intersecting near 1/F max, and indicating the following order of efficiency: Ni2+〉Ca2+〉Mn2+〉〉Mg2+. Hill plots for these cations resulted in straight lines with slopes near 1. Qualitatively similar relationships were obtained with contracture solutions containing D6000 (3–12 μmol/liter). However, under these conditions higher concentrations of Ca2+ or Ni2+ were required in order to fully maintain tension. After a step concentration change in the medium during contracture, the effects of Ca2+ or D600 were detectable only after a delay of 9 and 18 sec, respectively. It is concluded that divalent cations and D600 compete for the same binding site according to a 1:1 reaction. This site is presumably located inside the transverse tubular system and controls inactivation of the contractile force.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01871279
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  • 4
    Electronic Resource
    Electronic Resource
    Preparation and properties of composites of kevlar-nomex copolymer and boehmite (1997)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 248 (1997), S. 139-151 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ein neuartiges organisch-anorganisches Hybridmaterial wurde durch den Einbau des Minerals Böhmit mittels eines Sol-Gel-Prozesses in ein Kevlar-Nomex-Copolymeres hergestellt. Durch Reaktion eines Gemisches aus m- und p-Phenylendiamin mit Terephthaloylchlorid und anschließender Umsetzung mit Aminophenyltrimethoxysilan wurden Poly(phenylenterephthalamid)-Ketten mit Aminophenyltri-methoxysilan-Endgruppen synthetisiert. In dieser Polymermatrix wurde die Hydrolyse der Alkoxygruppen einer Lösung von Aluminium-sec-butanolat in Butanol durchgeführt. Dadurch wurde ein chemisch an die Aramid-Ketten gebundenes anorganisches Netzwerk aufgebaut. Aus den hergestellten Hybridmaterialien mit unterschiedlichen Böhmit-Gehalten in der Aramidmatrix wurden Filme gegossen. Die Filme aus Hybridmaterial mit bis zu 15 Gew.-% Böhmit waren transparent gelb, während bei 20 und mehr Gew.-% Böhmit opake Filme erhalten wurden. Die mechanischen Eigenschaften dieser Filme wurden untersucht. Zugfestigkeit, Zugmodul, Härte und maximale Bruchdehnung nahmen mit steigendem Böhmitgehalt zunächst zu, vemngerten sich jedoch bei weiterer Erhöhung des Mineralanteils wieder. Der Zugmodul des Hybridmaterials bei 25°C lag zwischen 3,0 und 4,5 GPa. Die Materialien hielten einer maximalen Zugspannung von 252 MPa stand und zeigten Zersetzungstemperaturen von etwa 450°C. Die rnit DMTA ermittelten Werte für den Speichemodul lagen im Bereich 7,6-18,9 GPa. Das tan δ-Signal verbreiterte sich mit zunehmendem Böhmitanteil und ging bei hohen Böhmitgehalten in eine Schulter über. Die Signalpositionen des Verlustfaktors wurden infolge der zunehmenden sterischen Einschränkung der Segmentbewegungen rnit steigendem anorganischen Anteil zu höheren Temperaturen verschoben.
    Notes: A new organic-inorganic hybrid material was prepared by incorporating boehmite into a Kevlar-Nomex copolymer via a sol-gel process. Poly(phenylene-terephthalamide) chains having aminophenyltrimethoxysilane end groups were prepared by reacting a mixture of m-and p-phenylenediamine with terephthaloyl chloride, followed by end-capping with aminophenyltrimethoxysilane. The hydrolysis of the alkoxy groups of an aluminium sec-butoxide solution in butanol was carried out in the polymer matrix, thus creating an inorganic network structure combined chemically with the aramid chains. Hybrid materials containing different proportions of boehmite in aramid were thus produced and films were cast by solvent evaporation technique. These films with up to 15 wt.-% of boehmite were yellow and transparent, whereas the films with 20 wt.-% or more contents of boehmite were opaque. Mechanical properties of these films were analyzed. The values of tensile strength, initial modulus, toughness and maximum strain at rupture were initially found to increase and then decrease with further addition of boehmite. The tensile modulus of the hybrid material was found to be in the range of 3.0-4.5 GPa at 25°C. These ceramers were found to withstand maximum tensile stress of the order of 252 MPa, and the thermal decomposition temperature was around 450°C. The storage modulus as measured using DMTA was in the range of 7.6-18.9 GPa. The tan δ peak which in general became broader with increasing boehmite content showed a shoulder for composites containing large amounts of boehmite. The position of the peaks shifted towards high temperature with the increase in the inorganic contents showing hindrance in motion with increasing boehmite contents.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1997.052480109
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  • 5
    Electronic Resource
    Electronic Resource
    Desaktivierungsverhalten von Arenen und Heteroarenen. XXXVI. Zum Lösungsmittel- und Temperatureinfluß auf das Desaktivierungsverhalten von 9, 9′-Bis(acridizinium-yl) bei hohen Konzentrationen (1983)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 325 (1983), S. 225-231 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deactivation Behaviour of Arenes and Heteroarenes. XXXVI. The Solvent and Temperature Dependence of Deactivation Behaviour of 9, 9′-Bis(acridizinium-yl) at High ConcentrationAt room temperature the geometrical structure of the fluoresceing singlet state of 9, 9′-bis(acridizinium-yl) is determined by the solvent. In solvents of the type A (water, methanol, acetonitril) a plain S1-state emits, in the case of the solvent type B (ethanol, propanol-(2)) the S1-state is twisted. Both excited states have different emission spectroscopical properties.At high concentration (c ≥ 10-4 mol l-1) in the case of the solvent type B a new emission band is observed, and the monomer emission is quenched. This new band is interpreted as a fluorescence from a molecular associate in the excited state. The intensity of this associate band is increasing with decreasing temperature. It is shown that this band is the result of molecular association in the ground state. From the photochemical irradiation it follows that only in the case of the solvent type B a photocycloaddition is possible. The plain S1-state does not react.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19833250207
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  • 6
    Electronic Resource
    Electronic Resource
    Neue Sol-Gel-Beschichtungen als Korrosions-und Verschleißschutz für NE-Metalle (1998)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 29 (1998), S. 23-29 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: New Sol-Gel Based Coatings as Corrosion- and Wear-Protection On Non-Ferrous MetalsA new composite coating material has been developed for the protection of non-ferrous alloys (e.g. aluminum, magnesium, zinc and brass). The coating materials were prepared by the solgel process from epoxyalkoxysilanes and aromatic diols to act as crosslinking agents. As solvent, alcohols and glycol ethers have been used.The viscosity of the system (7-55 mPas) was established in a way to be used in spray, dip or flow coating processes. The transparent coatings were cured at T = 100-220°C. In corrosion tests, 3000 hours salt-spray climate and 240 hours CASS-test = Copper chloride and Acetic acid added Salt Spray, no infiltration of the metal-coating interface and no „filiform-corrosion“ on A199.5, AlMg3 and AlMgSil was observed. Brass samples showed less than 4 mm extension of a scribe after 500 hours salt-spray-test. The coatings showed no visible traces of abrasion after 1000 cycles taber abrader test and an excellent adhesion (cross cut and tape-test: grade 0). The transparent basic systems were pigmented by 5 - 10 wt.% of colored organic pigments to obtain all kind of colored coatings.
    Notes: Es wurde ein neuer Beschichtungswerkstoff auf Basis von anorganisch-organischen Kompositen zum Schutz von Metalloberflächen, besonders von Aluminium entwickelt. Das Beschichtungsmaterial wurde über den Sol-Gel-Prozeß synthetisiert, ausgehend von Epoxy-funktionalisierten Alkoxysilanen und aromatischen Diolen als Quervernetzer. Als Lösungsmittel wurden Alkohole und Glykolether verwendet.Die Viskosität der Systeme wurde so eingestellt, daß sowohl Sprüh-, als auch Tauch- und Flut-Beschichtungen durchgeführt werden konnten. Sie lag zwischen 7 und 55 mPas. Nach dem thermischen Verdichtungsprozeß bei 100-220°C wurden transparente Beschichtungen mit ausgezeichneter Haftung auf Al-Mg-, Zn-und Messing-Oberflächen (Gitterschnitt- und Tape-Test: Klasse 0) erhalten. Die Korrosionsfestigkeit beschichteter Aluminiumlegierungen (Al 99.5, AlMg3, AlMgSi I) wurde mit dem Salzsprühverfahren (DIN 50021) und dem CASS-Test (NaCl, CuCl2·2H2O, Essigsäure, pH=3) geprüft und auch nach 3000 Stunden trat keine Unterwanderung der Grenzfläche Metall / Schicht auf. Ebenso wurde keine „Filiform“-Korrosion beobachtet. Messingproben zeigten nach 500 h Salzsprühnebel-Test weniger als 4 mm mittlere Unterwanderungsbreite. Darüber hinaus wurde die Abriebbeständigkeit der Proben überprüft. Die Schichten zeigten keine sichtbare Beschädigung nach Prüfung des Abriebes mit dem Reibradverfahren (1000 Zyklen, Räder: CS 10-F).Es konnten stabile Dispersionen von organischen Farbpigmenten im transparenten Basissystem hergestellt werden, wodurch eine große Vielfalt farbiger Beschichtungen erhalten wurde.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19980290108
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  • 7
    Electronic Resource
    Electronic Resource
    Massenspektroskopische Charakterisierung von ω-ChloralkylphenylphosphanenHerrn Prof. Dr. Siegfried Engels (Halle/S.) anläßlich seines 65. Geburtstages gewidmet (1997)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 339 (1997), S. 482-484 
    Details
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Mass Spectrometric Characterization of ω-Chloralkylphenylphosphines
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19973390187
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  • 8
    Electronic Resource
    Electronic Resource
    Einfluß von HCl und Cl2 auf die Hochtemperaturkorrosion des 2 1/4 Cr 1 Mo-Stahls in Atmosphären mit hohen Sauerstoffdrücken (1990)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 41 (1990), S. 303-307 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Influence of HCl and Cl2 on high temperature corrosion of 2 1/4Cr 1 Mo Steel in atmospheres with high oxygen pressuresThe oxidation of the 2 1/4 Cr 1 Mo steel was investigated at 773 K in oxidizing He-O2-HCl atmospheres. The addition of HCl to He-O2 atmospheres leads to accelerated oxidation rates. Below porous and cracked oxide scales condensed chlorides are formed. At low HCl pressures 0-1000 vppm the “active oxidation” is determining the corrosion process; i.e. oxidation of evaporating chlorides within the oxide scale. For higher HCl contents 1000-3000 vppm the corrosion behaviour changes to paralinear; i.e. simultaneous parabolic oxide growth and linear mass loss by chloride evaporation.
    Notes: Die Oxidation des 2 1/4Cr1Mo-Stahls in oxidierenden He-O2-HCl-Atmosphären bei 773 K wurde untersucht. Der Zusatz von HCl zu He-O2-Atmosphären führt zu stark beschleunigter Oxidation. Unter porösen und rissigen Oxidschichten bilden sich feste Chloride. Bei niedrigen HCl-Drücken 0-1000 vppm bestimmt „aktive Oxidation“ den Korrosionsprozeß; d.h. Oxidation flüchtiger Chloride innerhalb der Oxidschicht. Bei höheren HCl-Drücken 1000-3000 vppm erfolgt ein Übergang zum paralinearen Korrosionsverhalten, d.h. gleichzeitiges parabolisches Oxidwachstum und lineare Massenabnahme durch das Abdampfen von Chloriden.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19900410602
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  • 9
    Electronic Resource
    Electronic Resource
    Modifikation von Titan durch Ionenimplantation-Ein Überblick (1997)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 28 (1997), S. 88-97 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Modification of Titanium by Ion Implantation-A ReviewThis paper reviews investigations concerning the effect of ion implantation on the properties of titanium alloys. The correlations between the process parameters and the phase formation in implanted layers, the wear and strength properties as well as the corrosion and oxidation behaviour are described. The application for joint prostheses is mentioned.
    Notes: Es wird ein Überblick über den Einfluß der Ionenimplantation auf die Eigenschaften von Titanlegierungen gegeben. Die Beziehungen zwischen den Prozeßparametern und der Phasenbildung in ionenimplantierten Schichten, den Verschleiß- und Festigkeitseigenschaften sowie dem Korrosions- und Oxidationsverhalten werden dargestellt. Die Anwendung für Gelenkprothesen wird kurz besprochen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19970280210
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  • 10
    Electronic Resource
    Electronic Resource
    Gefüge und Korrosionsverhalten eines stickstofflegierten rostfreien Stahls (1998)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 29 (1998), S. 329-335 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Microstructure and Corrosion Behaviour of a Nitrogen Alloyed Stainless SteelThe corrosion behaviour of a nitrogen alloyed stainless steel is investigated using potentiodynamic anodic polarization in physiological NaCl solution. The microstructure of forged samples is determined by microscopy and hardness measurements. The steel shows a globular austenitic structure. In the zone of large forging deformation the grains are elongated. Precipitates are observed in which chromium and molybdenium are enriched. The breakdown potentials range from 200 to 1170 mV vs. SCE, most of the values exceed 500 mV. The breakdown potentials decrease with increasing aspect ratio of the grains and increasing hardness. The precipitates are initial sites for pitting and crater shaped metal dissolution.
    Notes: Das Korrosionsverhalten eines stickstofflegierten rostfreien Stahles wird durch potentiodynamische anodische Polarisation in physiologischer NaCl-Lösung untersucht. Der Gefügezustand geschmiedeter Proben wird mikroskopisch und durch Härtemessungen ermittelt. Der Stahl weist ein globulares austenitisches Gefüge auf, in der Zone starker Schmiedeverformung sind die Körner gestreckt. Es liegen Ausscheidungen vor, in denen Chrom und Molybdän angereichert sind. Der Stahl zeigt Durchbruchspotentiale zwischen 200 und 1170 mV vs. SCE, die meisten Werte liegen über 500 mV. Die Durchbruchspotentiale fallen mit zunehmendem Streckungsgrad der Körner und zunehmender Härte ab. Die Ausscheidungen sind Initialpunkte für loch- und kraterförmigen Materialabtrag.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19980290704
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