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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 8 (1996), S. 0 
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The functional interaction of thiocyanate (SCN-) ions with recombinant non-N-methyl-D-aspartate receptors was examined by studying α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)- and kainic acid (KA)-activated currents in Xenopus laevis oocytes. Recombinant receptors were expressed after microinjection of oocytes with combinations of cDNAs or cRNAs encoding for GluR1, GluR2, GluR2(R586Q), GluR3 or GluR6 subunits. When the GluR2 subunit was expressed with GluR1, SCN- (2 mM) inhibited the responses to 50 μM AMPA, whereas responses to 100 μM KA were slightly increased and responses to 200 μM L-glutamate were unaffected. Equilibrium concentration-response curves for AMPA were antagonized in a non-competitive manner by SCN- with a reduction in the EC50. The inhibitory effects of SCN- were unaffected by prior reduction of receptor desensitization with either 10 μM Concanavalin-A or 0.5 mM diazoxide. AMPA-activated currents recorded from homomeric GluR1 or GluR3 receptors were not affected by SCN-, and GluR6 homomeric receptors, which are sensitive to KA but not to AMPA, were also unaffected. In contrast, AMPA activation of homomeric GluR2(R586Q) subunit receptors, or combinations of GluR1 or GluR3 + GluR2(R586Q) subunits, were markedly inhibited by SCN-. In addition, the inhibitory effect of AMPA on KA-activated responses on these heteromeric receptors, was enhanced by SCN-. These results indicate that SCN- exert an inhibitory effect on ‘AMPA receptors’but only when the recombinant non-NMDA receptor is a GluR2 homomer, or when GluR2 subunits are present as part of a heteromeric combination. Moreover, this inhibitory effect was unaffected by the ‘Q/R’site in the presumed second transmembrane domain, since currents mediated by the GluR2(R586Q) subunit were also susceptible to inhibition by SCN-. Thus the inhibition was not related to the rectification properties or calcium permeability of the non-NMDA receptors. It is suggested that the GluR2 subunit may have a specific binding site for anions which could modulate the function of non-NMDA receptors and that SCN- may be a useful probe for the detection of these subunits in native neurons.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 36 (1997), S. 191-197 
    ISSN: 1436-6215
    Keywords: Cooked starch ; diet ; oral breakdown ; glucose ; HPLC analysis ; lactic acid ; oral fluid ; organic acids ; sugars ; saliva ; gekochte Stärke ; Nahrung ; oraler Abbau ; Glukose ; HPLC-Analyse ; Milchsäure ; Mundflüssigkeit ; organische Säuren ; Zucker ; Speichel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Nach dem Genuß von sechs zucker- und/oder stärkehaltigen Nahrungsmitteln (Schokoladenriegel, Kartoffelchips, gefüllter Keks, Würfelzucker, Rosinen und Geleebohnen) wurde der Kohlenhydratabbau und die Säureproduktion im Mund über zwei Stunden verfolgt und analysiert. Jedes Nahrungsmittel wurde an acht Probanden in Zeitintervallen von 30 min untersucht. Die Freisetzung von Glukose und die Bildung von Milchsäure im Mund wurden mittels HPLC-Analyse qualitativ und quantitativ über zwei Stunden verfolgt und statistisch ausgewertet. Innerhalb der ersten 30 Minuten wurde Milchsäure in folgender Rangordnung produziert: (höchster Wert) Rosinen 〉 Schokoladenriegel 〉 Würfelzucker 〉 Geleebohnen 〉 gefüllter Keks 〉 Kartoffelchips (niedrigster Wert); nach 120 Minuten änderte sich diese Rangordnung wie folgt: Kartoffelchips 〉 Geleebohnen 〉 Würfelzucker 〉 Schokoladenriegel 〉 gefüllter Keks 〉 Rosinen. Die Menge der produzierten Milchsäure war linear abhängig von der Menge der von den Speisen freigesetzten Glukose. Gekochte Stärke wurde im Mund über Maltotriose und Maltose zu Glukose abgebaut. Klebrige (zuckerhaltige) Nahrungsmittel (Schokoladenriegel) verlassen die Mundhöhle schneller als Nahrungsmittel, die gekochte Stärke enthalten (Kartoffelchips); letztere produzieren daher über einen längeren Zeitraum (2 h) im Munde mehr Milchsäure.
    Notes: Summary Oral carbohydrate clearance and acid production were monitored over a two hour time period following the ingestion of six foods (chocolate bar, potato chip, oreo cookie, sugar cube, raisin and jelly bean). Each food was evaluated intra-orally in eight volunteers. Oral fluid samples were obtained from each volunteer at 30 min intervals at five different tooth sites using absorbent paper points. The oral fluid samples were analyzed qualitatively and quantitatively for carbohydrates and organic acids using high performance liquid chromatography. Data obtained for each food were averaged and subjected to statistical analysis. The quantity of lactic acid produced 30 min after ingestion was found to be in the following order: (highest) raisin 〉 chocolate bar 〉 sugar cube 〉 jelly bean 〉 oreo cookie 〉 potato chip (least). Two hours after food intake the order had changed significantly: potato chip 〉 jelly bean 〉 sugar cube 〉 chocolate bar 〉 oreo cookie 〉 raisin. A direct linear relationship existed between lactic acid production and the presence of glucose. In foods containing cooked starch prolonged clearance occurs via the intermediate metabolites maltotriose, maltose and glucose. Results indicated that the term ‘stickiness’, when used to label certain foods such as jelly bean and chocolate bar, should be used cautiously. Foods containing only cooked starch or cooked starch and sugars can be considered as ‘sticky’, since glucose arising from their intra-oral degradation contributed to acid production over prolonged periods of time.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 31 (1992), S. 147-154 
    ISSN: 1436-6215
    Keywords: Sugars ; carbohydrates ; lacticacid ; oralfluid ; HPLC ; glucose ; sucrose ; Zucker ; Kohlenhydrate ; Milchsäure ; Speichel ; HPLC-Analyse ; Glukose ; Saccharose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Eine empfindliche HPLC-Methode wurde für die qualitative und quantitative Analyse von Kohlehydraten und organischen Säuren in Mundflüssigkeiten (Speichel und Zahnplaque) entwickelt. Für die Trennung dieser Verbindungen wurde eine Aminex HPX-87H (Bio-Rad) Chromatographie-Säule verwendet. Alle Komponenten des HPLC-Systems waren mit Edelstahl-Kapillaren verbunden. Die isokratische Elution beider Verbindungs-Klassen erfolgte mit 0,01 n Schwefelsäure. Alle Verbindungen wurden mit einem RI-(Refraktion-Index-) Detektor gemessen. Die Ergebnisse wurden mit einem PC-gestütztem Auswertesystem automatisch gesammelt und integriert. Die zeitbedingte Abnahme der Konzentration von Kohlehydraten im Munde einerseits und die Produktion von organischen Säuren durch Bakterien der Mundhöhle andererseits können mit dieser empfindlichen HPLC-Methode bis zu einer Genauigkeit von 0,1 µg Substanz per Analyse (80 µl) bestimmt werden.
    Notes: Summary A sensitive high performance liquid chromatography (HPLC) assay was developed for the qualitative and quantitative determination of carbohydrate sweeteners and organic acids in oral fluid. To separate these compounds, an ion-moderated partition resin HPLC column (Aminex HPX-87H) was used. All components of the HPLC system were interconnected using stainless steel capillary tubing. Isocratic elution with 0.01 N sulfuric acid provided the profile of both compound classes. The compounds were detected using a refractive index detector. The method employed computerized data collection and integration (Omega-2 system) with a detection sensitivity of 0.1 µg compound per HPLC assay (80 µl). This method is useful in caries research, because it detects minute amounts of sugars and organic acids in oral fluid during clearance studies of various foods in the mouth.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 6 (1986), S. 401-416 
    ISSN: 1572-8986
    Keywords: Plasma oxidation ; polymers ; copolymers ; mechanism ; plasma-developable resists
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The rates of plasma oxidation have been measured for homopolymers of several monomers and for copolymers of methyl methacrylate with styrene and vinyl naphthalene. Our results show that relatively small amounts of the aromatic component in the copolymer convey substantially increased resistance to plasma oxidation. Current knowledge of the mechanisms of plasma oxidation is reviewed and new mechanistic explanations are suggested. The implications for improved design of plasma-developable resists systems are considered.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Competitive studies of the reactions of ground-state oxygen atoms, generated by mercury-photosensitized decomposition of nitrous oxide, have been carried out with ethylene and all the fluoroethylenes using 2-(trifluoromethyl)-propene as reference compound. From measurements at 25°C and 150°C relative rate constants have been determined and used to calculate the Arrhenius parameters shown in the following table: TextOlefin\documentclass{article}\pagestyle{empty}\begin{document}$$\frac{{A_{{\rm olefin}} }}{{A_{{\rm 2TFMP}} }}$$\end{document}ΔERef\documentclass{article}\pagestyle{empty}\begin{document}$$\frac{{A_{{\rm olefin}} }}{{A_{{\rm C}_{\rm 2} {\rm H}_{\rm 4} } }}$$\end{document}ΔEC2H4CH2—CH21.10-1.18(1.0)(0)CH2—CHF1.030.840.942.02CH2—CF20.711.490.652.67CHF—CHF (cis-)1.231.921.123.10CHF—CHF (trans-)1.400.791.271.97CF2—CHF1.060.000.961.22CF2—CF20.86-3.220.78-2.04ΔERef = Eolefin - E2TFMP and ΔEC2H4 = Eolefin - EC2H4. Units are kJ/mole.The results are compared with corresponding data for other atoms and radicals, and discussed in terms of the electronic changes produced in the double bond by fluorine substitution, and in relation to the nature of the transition state.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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