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  • 1
    Electronic Resource
    Electronic Resource
    Organogenetic capacity of leaves: The significance of marginal blastozones in angiosperms (1996)
    Springer
    Plant systematics and evolution 199 (1996), S. 121-152 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Leaf development ; organismal approach ; blastozone ; organogenetic competence ; primary morphogenesis ; marginal meristems ; topography ; eumeristem ; cytohistological gradients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new term — the “blastozone” — is proposed to designate regions of the shoot competent for organogenesis. It is argued that the notion of “marginal meristems” is based on the cell theory and thus may not be appropriate to elucidate the process of organ formation. For instance, with respect to the occurrence of initials and of an elevated cell division rate marginal meristems have been shown to be doubtful structures. Furthermore, organogenetic competent regions form only parts of the meristems of the shoot. The study of blastozones from an organismic perspective reveals primary morphogenetic events such as initiation, incorporation, and fusion processes. Loss of morphogenetic competence is associated with histogenetic events, e.g., trichome outgrowth, and indicates the onset of processes leading to maturation. The marginal blastozone of the leaf is then used up although meristem features continue to be expressed. A series of SEM studies in several genera exemplifies the proposed viewpoint, demonstrating some of the morphogenetic potentialities of angiosperm leaf marginal blastozones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984901
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  • 2
    Electronic Resource
    Electronic Resource
    The cytological basis of the plastid inheritance in angiosperms (1989)
    Springer
    Protoplasma 152 (1989), S. 57-64 
    Details
    ISSN: 1615-6102
    Keywords: Angiosperms ; Plastid inheritance, uniparental ; Plastid inheritance, biparental ; Plastid distribution ; Plastid transmission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01323062
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  • 3
    Electronic Resource
    Electronic Resource
    On subspecific taxa ofHypericum empetrifolium (Hypericaceae) from Crete (1987)
    Springer
    Plant systematics and evolution 155 (1987), S. 165-187 
    Details
    ISSN: 1615-6110
    Keywords: Angiosperms ; Guttiferae ; Hypericaceae ; Growth form ; vicarious taxa ; nomenclature ; Flora of the Mediterranean ; of Greece ; of Crete
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology, altitudinal distribution and phytocoenology ofHypericum empetrifolium Willd., var.oliganthum Rech. fil. and var.tortuosum Rech. fil. are reassessed and as a result, the taxa are treated at subspecific rank. Essential characters proved to be growth form, number of flowers, foliage and epidermal surface characters, shape of seeds and testa sculpturing. The different growth forms can be interpreted as adaptations to the local habitats.Hypericum empetrifolium Willd. subsp.empetrifolium is a low subshrub of various vegetation types known as phrygana whereasHypericum empetrifolium Willd. subsp.oliganthum (Rech. f.)Hagemann grows as a cushion-like dwarf shrub in chasmophyte associations rich in relic species.Hypericum empetrifolium Willd. subsp.tortuosum (Rech. f.)Hagemann is confined in the high mountain regions and grows as a true dwarf espalier shrub with low spreading shoots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00936297
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  • 4
    Electronic Resource
    Electronic Resource
    Polytrifluormethylstyrole, eine polymerklasse mit aussergewöhnlichen optischen eigenschaftenVortrag anläßlich der Tagung der Fachgruppe “Makromolekulare Chemie” der Gesellschaft Deutscher Chemiker über “Synthetische Polymere mit außergewöhnlichen Eigenschaften” in Bad Nauheim am 19. und 20. April 1982Herrn Prof. Dr. Otto Bayer in memoriam gewidmet (1982)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 109 (1982), S. 285-293 
    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: Homopolymers of 2-, 3- and 4-trifluoromethylstyrene, 4-perfluoroisopropylstyrene, 3,5-bis-trifluoromethyl-styrene and a 1 : 1 copolymer of 2,4- and 2,5-bis-trifluoromethyl-styrene have been synthesized and the refractive indices nD, Abbe-numbers νD and glass transition temperatures of the polymers have been determined.With regard to optical applications poly-2-trifluoromethyl-styrene is particularly interesting since its optical properties are in a region of the n-ν-diagram that has not been reached by thermoplastic polymers or inorganic glasses before.The most important mechanical and thermal properties of this polymer are reported. Reactivity ratios of the binary copolymerisation of 2-trifluoromethyl-styrene with styrene, methyl-methacrylate and n-butyl-acrylate are listed as well as optical data and glass transition temperatures of some copolymers of 2-trifluoromethyl-styrene.
    Notes: Homopolymerisate aus 2-, 3- und 4-Trifluormethylstyrol, 4-Perfluorisopropylstyrol, 3,5-Bis-trifluormethylstyrol und ein 1 : 1 Copolymerisat aus 2,4- und 2,5-Bis-trifluormethylstyrol wurden hergestellt und Brechungsindices, Abbe-Zahlen sowie Glasübergangstemperaturen der Polymerisate bestimmt.Von diesen Thermoplasten ist das Poly-2-trifluormethylstyrol im Hinblick auf optische Anwendungen besonders interessant, da es in einem weder von anorganischen Gläsern noch von bekannten thermoplastischen Kunststoffen bisher erreichten Gebiet des n-v-Diagrammes liegt.Die wichtigsten mechanischen und thermischen Eigenschaften dieses Polymeren und die Copolymerisationsparameter für die binäre Copolymerisation von 2-Trifluormethylstyrol mit Styrol, Methylmethacrylat und n-Butylacrylat wurden bestimmt. Optische Daten und Glastemperaturen einiger Copolymerisate des 2-Trifluormethylstyrols werden mitgeteilt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1982.051090119
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  • 5
    Electronic Resource
    Electronic Resource
    [2π + 2π]-Photocycloadditionen in Tricyclo[3.2.2.02,4]nonadien-Derivaten. Synthese einfach überbrückter Tris-σ-homobenzol-Verbindungen (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1971-1987 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [2π+2π]-Photocycloaddition Reactions in Tricyclo[3.2.2.02.4]nonadiene Derivatives. Synthesis of Singly Bridged Tris-σ-homobenzene CompoundsThe direct - not, however the acetone sensitized -excitation (λ 〉 280 nm) of the tricyclo-[3.2.2.02,4]nonadiene diester 6a - c and the bis-trifluoromethyl derivatives 6d, e (Δ 〉 230 nm), resp., yields (60-90%) the pentacycles 7a - e resulting from a [2π + 2π]-cycloaddition reaction. A [2π + 2σ]-addition with participation of the cyclopropane ring (leading to 8a - e) is not observed. With comparable selectivity (〉 90% isolated yield) the [2π + 2π]-cyclisation takes place in the 3-oxa-diester 10 (to 11). The tris-σ-homobenzene compounds 7a - e and 11, resp. are thermally isomerized exclusively in a 2σ → 2π-cleavage to the starting dienes 6a - e and 10, resp. (Ea (7a) = 22 kcal/mole; A = 2.2·1012 S-1-1). As exemplary cases the addition of HCl, CH3OH and H2O to the diester 7a and to the dicarboxylic acid 7g, resp., has been studied; in a rather selective way the adducts 13 and 14 (ratio 9:1) are formed in good yields. With the usual attack upon the nonsubstituted edge of the bishomocyclobutadiene partial structure in 7a being sterically hindered, tetracyanoethylene forms the 1:1 adducts 15 and 16.
    Notes: Die direkte - nicht aber die aceton-sensibilisierte -Lichtanregung (λ 〉 280 nm) der Tricyclo[3.2.2.02,4]nonadien-diester 6a - c bzw. der Bis-trifluormethyl-Derivate 6d,e (λ 〉 230 nm) liefert in 60-80 proz. bzw. 90 proz. Ausbeute die aus einer [2π + 2π]-Cycloaddition resultierenden Pentacyclen 7a - e. Eine [2π + 2σ]-Reaktion unter Beteiligung des Cyclopropanringes (zu 8a - e) ist daneben nicht nachweisbar. Gleichermaßen einheitlich (isolierte Ausbeute 〉 90%) verläuft die [2π + 2π]-Cyclisierung im 3-Oxa-Diester 10 (zu 11). Die Tris-σ-homobenzole 7a - e bzw. 11 werden thermisch ausschließlich unter 2σ → 2π-Spaltung zu den Ausgangsdienen der Photoreaktionen 6a - e bzw. 10 isomerisiert (Ea (7a) = 22 kal/mol; A = 2.2·1012s-1). Am Beispiel des Diesters 7a bzw. der Dicarbonsäure 7g wurde die Addition von HCl und CH3OH bzw. Wasser studiert, wobei selektiv die Addukte 13 und 14 (Verhältnis 9:1) in durchweg guten Ausbeuten gewonnen werden. Bei sterischer Behinderung des üblichen Angriffs auf die unsubstituierte Kante des Bishomocyclobutadien-Partialgerüsts in 7a setzt sich TCÄ zu den 1:1-Addukten 15 und 16 um.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070620
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  • 6
    Electronic Resource
    Electronic Resource
    [2π + 2π]-Photocycloadditionen in Bicyclo[2.2.2]octadien-Derivaten (1974)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 107 (1974), S. 1957-1970 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: [2π+2π]-Photocycloaddition Reactions in Bicyclo[2.2.2]octadiene DerivativesAs exemplified by the dieser 14a a [2π + 2π]-photocycloaddition in the bicyclo[2.2.2]octadiene skeleton is possible by direct - not, however, by sensitized - excitation. Besides a small fragmentation to dimethylphthalate (and ethylene) no other phototransformation of 14a takes place. With a half-life of ca. 12 min at 19°C the photoproduct 15a is thermally isomerized back to the diene diester 14a. Via a regiospecific addition of HCl, methanol and water to the tetracycles 15a and 15b (H2O) the epimeric products 18, 19 are isolated in a ratio of ca. 9:1. Their structure is elucidated by oxidation of 18c to 21 and 1H-n.m.r. spectroscopic comparison with the isomeric compounds 20 and 22, resp., synthesized by a different route. Towards bishomodienophilic reagents like tetracyanoethylene and dimethyl acetylenedicarboxylate 15a shows the expected reactivity. The addition proceeds at the nonsubstituted edge of the bishomocyclobutadiene unit yielding 24, and 26.
    Notes: Am Beispiel des Diesters 14a wird gezeigt, daß auch im Bicyclo[2.2.2]octadien-Gerüst durch direkte Lichtanregung -nicht jedoch sensibilisiert - eine [2π + 2π]-Cycloaddition möglich ist. Außer einer geringfügigen Fragmentierung zu Phthalsäure-dimethylester (und Äthylen) findet keine konkurrierende Photoumwandlung von 14a statt. Mit einer Halbwertszeit von ca. 12 min bei 19°C isomerisiert sich das Photoprodukt 15a zurück zum Dien-diester 14a. Bei der regiospezifischen Addition von HCl, Methanol und Wasser an die Tetracyclen 15a, 15b (H2O) werden die Epimeren 18, 19 im Verhältnis von ca. 9:1 isoliert. Deren Struktur ist durch Oxidation von 18c zu 21 sowie 1H-NMR-spektrometrischen Vergleich mit den auf anderem Weg synthetisierten Isomeren 20 und 22 gesichert. Auch gegenüber bishomodienophilen Partnern wie Tetracyanäthylen oder Acetylendicarbonsäure-dimethylester besitzt 15a die erwartete Reaktivitat. Die Addition erfolgt stereospezifisch an die nichtsubstituierte Kante des Bishomocyclobutadienteils zu 24 und 26.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19741070619
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  • 7
    Electronic Resource
    Electronic Resource
    A Vibrational Study of Some 1,2,4-Trioxanes (1988)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 71 (1988), S. 992-999 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The vibrational spectra of some 1,2,4-trioxanes present two characteristic bands at 790 and 880 cm-1. On the basis of 18O-isotopic substitution and comparison with analogous compounds, these bands have been assigned to coupled C—O and O—O stretching modes of the C—O—O element.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19880710508
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  • 8
    Electronic Resource
    Electronic Resource
    Thermolysis and Chemiluminescence of Monocyclic 1,2,4-Trioxan-5-ones (1994)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 77 (1994), S. 1851-1860 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 3,6-substituted 1,2,4-trioxan-5-ones 11-14, on heating to 170-200°, underwent unimolecular thermolysis to generate electronically excited singlet ketones with an efficiency of ca. 0.2%. The chemiluminescence quantum yields (φoSCL) depended on the nature of the 6-substitutents and increased linearly with temperature. The Arrhenius activation energies were obtained by measuring the rate of decay of luminescence and determined as 22.9, 30.4, 35.6, and 34.2 kcal/mol for 11-14, respectively. Step analysis of the chemiluminescence of 14 afforded an average activation energy of 44.3 kcal/mol. This latter result is explicable in terms of two decomposition paths, higher and lower in energy, leading to excited and ‘dark’ products, respectively. The thermolysis of trioxanones 12-14 lacking a H-atom at the 6-position is interpreted as involving successive rupture of the peroxide bond, excision of ketone at the 3-substituted end, and loss of CO2, to finally produce ketone originating from the 6-position (see Scheme 4).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19940770716
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  • 9
    Electronic Resource
    Electronic Resource
    Systematic analysis of desorption chemical ionization (DCI) mass spectra of nucleic acids - 7For part VI,see Ref.6. (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1983), S. 559-566 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The positive ion and negative ion pyrolysis mass spectra of the herring sperm DNA have been studied using desorption chemical ionization. The positive ion desorption chemical ionization spectra have been produced with CH4, i-C4H10, NH3, HCl and Cl2; the negative ones with N2O/CH4, N2O/i-C4H10, Cl2, CCl4, HCI and via electron capture. These spectra have been compared with the electron impact ionization spectra. We have observed an important increase of sensitivity when negative ionization has replaced the positive ionization mode. The series of diagnostic ions resulting from direct chemical ionization belong to the family of base + reagent ion X [BH + X] and base + X-HX ion [B]. Their abundance has increased considerably compared to the electron impact spectra. The application of these new diagnostic ions in nucleic acid studies is interesting especially for the much higher abundance of the usually weak dG fragment ion obtained in the negative ionization mode. The dG-base segment of the DNA is the most nucleophilic centre of the whole nucleic acid and is implicated in numerous important biochemical reactions involving, for example, proteins.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200101006
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  • 10
    Electronic Resource
    Electronic Resource
    Darstellung aliphatischer Amadori-Produkte (1959)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 92 (1959), S. 2836-2840 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die bisher nur aus 4.6-Benzal-N-D-glucosiden aliphatischer Amine in kristalliner Form durch Amadori-Umlagerung zugänglichen entsprechenden Derivate der 1-Desoxy-1-amino-D-fructose lassen sich ebenfalls aus den N-D-Glucosiden der 4.6-Dimethyl-D-glucose leicht erhalten. Unter geeigneten Bedingungen können auch die Amadori-Produkte nicht in 4.6-Stellung substituierter N-D-Glucoside aliphatischer Amine bequem und in hoher Ausbeute kristallin gewonnen werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19590921127
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