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  • 1
    Electronic Resource
    Electronic Resource
    Effects of ethylenic bond position upon acyltransferase activity with isomeric cis-octadecenoyl coenzyme a thiol esters
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism 176 (1969), S. 480-490 
    Details
    ISSN: 0005-2760
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2760(69)90215-X
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of 1,6-diazaphenalene (1981)
    s.l. : American Chemical Society
    The @journal of organic chemistry 46 (1981), S. 4188-4193 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00334a016
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  • 3
    Electronic Resource
    Electronic Resource
    Pathological mechanisms in polycystic ovary syndrome: modulation of LH pulsatility by progesterone (1984)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 91 (1984), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The pulsatile discharge of luteinizing hormone (LH) in nine patients with polycystic ovary syndrome (PCO) and nine patients with amenorrhoea but without PCO, who exhibited LH discharge in response to oestrogen provocation, were studied by 4-h measurement of gonadotrophin pulsatility before and after a course of progesterone injections. No significant differences were found in the gonadotrophin pulsatility patterns of the two groups, although the LH/FSH ratio rose significantly in the patients without PCO after progesterone but not in the patients with PCO, suggesting an abnormality of FSH storage. The ability to discharge gonadotrophins in response to oestrogen provocation has been reported to be present in patients with 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:14700328:BJO457:ges" location="ges.gif"/〉3 LH pulses in a 4-h study period. This, however, was not demonstrated in five of the nine PCO patients despite the presence of ‘normal’ gonadotrophin pulsatility patterns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1984.tb04784.x
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  • 4
    Electronic Resource
    Electronic Resource
    Heterogeneous decomposition ofp-methoxy- andp-methyl-dibenzoyl peroxides by a montmorillonite amine intercalate (1986)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 4 (1986), S. 169-175 
    Details
    ISSN: 1573-1111
    Keywords: Montmorillonite ; decomposition of organic peroxides ; heterogeneous catalysis and benzidine reaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A kinetic study of the heterogeneous thermal decomposition ofp-MeO-DBP andp-Me-DBP catalysed by the montmorillonite benzidine intercalate has been made. The kinetics of decomposition were observed to follow a three-halves order reaction with respect to the peroxides. The activation parameters in heterogeneous media have lower values compared with the corresponding values in homogeneous ones. The relationships between ΔH * and ΔS * were plotted and show two converging straight lines which indicate that both electron donating and withdrawing substituents on the peroxide enhance the rate of decomposition under these conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655931
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  • 5
    Electronic Resource
    Electronic Resource
    Catalytic decomposition of organic peroxides by 4,4′-diamino-trans-stilbene (DTS)/montmorillonite complex. I. dibenzoyl peroxide (DBP) (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 379-387 
    Details
    ISSN: 1573-1111
    Keywords: Montmorillonite ; intercalation ; heterogeneous catalysis ; dibenzoyl peroxide ; 4,4′-diamino-trans-stilbene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The decomposition of DBP was studied in the presence of DTS in an ethanolic homogeneous solution and with DTS intercalated in montmorillonite clay mineral as a heterogeneous reaction. The kinetic parameters obtained from the two systems were monitored and indicated that the homogeneous system follows second order reaction kinetics for DBP, whereas the heterogeneous one follows a three-halves order. The heterogeneous system was found to possess higher catalytic efficiency and the reaction was shown to take place within the internal surfaces of the clay mineral. This was attributed to the great surface area of the catalyst, Lewis and Brönsted acid sites and its great ability to sorb the polar organic species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00657489
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetics of heterogeneous decomposition of hydrogen peroxide (1986)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 4 (1986), S. 359-367 
    Details
    ISSN: 1573-1111
    Keywords: H2O2 decomposition ; Wofatit KPS-resin ; Cu(II)-ammine complex ions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of the decomposition of hydrogen peroxide was studied in aqueous medium in the temperature range 25–40°C in the presence of Wofatit KPS-resin in the form of Cu(II)-ammine complex ions. The rate constant was deduced at various degrees of resin cross-linkage and different concentrations of hydrogen peroxide. The order of the decomposition reaction varied from first order to half order, i.e., the order of the reaction decreased with increasing the concentration of H2O2. The decomposition process was found to be a catalytic reaction which was controlled by the chemical reaction of H2O2 molecules with the active species inside the resin particles. The mechanism of the reaction can be summarized by the equation $$ - {\text{d}}\left[ {{\text{H}}_{\text{2}} {\text{O}}_{\text{2}} } \right]/{\text{d}}t = k_1 {\text{ }}\sqrt {K_1 } K_2 \left[ {{\text{H}}_{\text{2}} {\text{O}}_{\text{2}} } \right]\left[ {{\text{Cu}}\left( {{\text{NH}}_{\text{3}} } \right)_4 } \right]^{2{\text{ }} + } /\left[ {{\text{H}}^{\text{ + }} } \right]$$ in which the subsequent reactions of the probable active complex are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656163
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  • 7
    Electronic Resource
    Electronic Resource
    Catalytic decomposition of organic peroxides by 4,4′-diamino-trans-stilbene (DTS)/montmorillonite complex: II.p-nitro andp-methyl dibenzoyl peroxide (1987)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 5 (1987), S. 675-682 
    Details
    ISSN: 1573-1111
    Keywords: Organic peroxide reactions ; montmorillonite/4,4′-diaminostilbene intercalate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The kinetics of the induced decomposition ofp-NO2- andp-CH3-dibenzoyl peroxide in the presence of 4,4′-diamino-trans-stilbene (DTS) were studied in ethanol under both homogenous and heterogeneous conditions. The heterogeneous reaction was carried out in the presence of the DTS/montmorillonite complex. The decomposition reaction was found to be second order and three-halves order for the peroxide concentration in homogeneous and heterogeneous systems, respectively. The reaction was first order for the amine concentration in the homogeneous system. The activation energies for the decomposition reaction were obtained as 54.7±2 and 59.5±3 kJ mol−1 forp-NO2- andp-CH3-dibenzoyl peroxides, respectively, in the homogeneous systems and are higher than the corresponding values of 41±1.5 and 47.6±1 kJ mol−1 for thep-NO2 andp-CH3 derivatives in heterogeneous media.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00656586
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  • 8
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of the decomposition of hydrogen peroxide catalyzed by Mn(II)-bis-salicylaldimine complexes (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 393-399 
    Details
    ISSN: 1434-4475
    Keywords: Hydrogen peroxide ; Manganese ; TetradentateSchiff base ; Kinetics ; Decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die teradentatenSchiffschen Basen N,N′-bis-Salicyliden-ethylendiamin (salen), N,N′-bis-Salicyliden-Hexylendiamin (salhex) und N,N′-bis-Salicyliden-o-phenylendiamin (sal-o-phen) werden von Kationenaustauschen (Dowex-50W) mit Mangan(II) als Gegenion unter der Bildung stabiler Komplexe adsorbiert. Die Kinetik der katalytischen Zersetzung von H2O2 in Gegenwart dieser Komplexe wurde in wäßrigem Medium untersucht. Die Zersetzungsreaktion ist erster Ordnung bezüglich H2O2 in den Fällensalen undsal-o-phen und dritter Ordnung im Fall vonsalhex. Die Reaktionsgeschwindigkeit steigt mit der Länge der Methylenkette des Liganden und mit dessen Raumbedarf und wird von der Aktivierungsentropie bestimmt. Ein Reaktionsmechanismus wird vorgeschlagen.
    Notes: Summary The tetradentateSchiff bases N,N′-bis(salicylidene) ethylenediamine (salen), N,N-bis-(salicylidene) hexylenediamine (salhex), and N,N′-bis(salicylidene)-o-phenylenediamine (sal-o-phen) are very strongly adsorbed by cation exchange resins (Dowex-50W) with manganese(II) as a counter ion, forming stable complexes. The kinetics of the catalytic decomposition of H2O2 in presence of these complexes has been studied in aqueous medium. The decomposition reaction is first order with respect to H2O2 in the case ofsalen andsal-o-phen and third order in the case ofsalhex. The greater the ligand methylene chain length or the greater the steric effect of the ligand, the greater will be the rate of reaction. The reaction is governed by the entropy of activation. A reaction mechanism is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00813201
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  • 9
    Electronic Resource
    Electronic Resource
    Species richness and phenology of vegetation along irrigation canals and drains in the Nile Delta, Egypt (1994)
    Springer
    Plant ecology 112 (1994), S. 35-43 
    Details
    ISSN: 1573-5052
    Keywords: Aquatic vegetation ; Life form ; River Nile ; Salinity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This study evaluates the species richness, phenology and effect of environmental factors on the composition of canal and drain vegetation in the Nile Delta, Egypt. Altogether, 365 stands were sampled along the terraces, slopes, littoral zones and water zones of 28 canals and 10 drains. Smooth species compositional changes were found in the first three zones. The slope plant community has the highest total number of species and species richness and a medium value of species turnover. The water zone has the lowest values of these variables. The number of species with seedlings and vegetative plants had two peaks: one in winter and the second in summer, which was related to the contrasted behaviour of the winter and summer weeds. The number of species with vegetative and fruiting plants was relatively higher, while the number with dormant plants was relatively lower in the canal vegetation when compared to that of the drains. The number of species with vegetative, flowering and fruiting plants increased with the decrease of canal-drain width.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00045098
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  • 10
    Electronic Resource
    Electronic Resource
    Oxidation kinetics of p-aminodiphenylamine with peroxydisulphate (1993)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 6 (1993), S. 609-614 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of oxidation of p-aminodiphenylamine with the peroxydisulphate ion were investigated spectrophotometrically. The oxidation was accompanied by the appearance of a wine-red colour, which changed to become colourless. The reaction rate was measured by the stopped-flow technique with a UV spectrophotometer. The reactions proceeded with second-order kinetics, first-order for each individual reactant. Cationic micelles (cetyltrimethyl ammonium bromide) caused an enhancement in the reaction rate followed by inhibition at higher concentrations. Anionic micelles (sodium dodecyl sulphate), on the other hand, had a slightly retarding effect. The effects of radical scavenger, pH and ionic strength on the fast oxidation rate were examined. A mechanism consistent with the observations is discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610061103
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