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  • 1
    Digitale Medien
    Digitale Medien
    Frost hardening and photosynthetic performance of Scots pine (Pinus sylvestris L.) needles. I. Seasonal changes in the photosynthetic apparatus and its function (1998)
    Springer
    Planta 204 (1998), S. 193-200 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Key words: Chlorophyll ; Chlorophyll-binding protein ; Frost hardening ; Photosynthesis ; Pinus (frost hardening)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract. Photosynthetic CO2 uptake, the photochemical efficiency of photosystem II, the contents of chlorophyll and chlorophyll-binding proteins, and the degree of frost hardiness were determined in three-year-old Scots pine (Pinus sylvestris L.) trees growing in the open air but under controlled daylength. The following conditions were compared: 9-h light period (short day), 16-h light period (long day), and natural daylength. Irrespective of induction by short-day photoperiods or by subfreezing temperatures, frost hardening of the trees was accompanied by a long-lasting pronounced decrease in the photosynthetic rates of one-year-old needles. Under moderate winter conditions, trees adapted to a long-day photoperiod, assimilated CO2 with higher rates than the short-day-treated trees. In the absence of strong frost, photochemical efficiency was lower under short-day conditions than under a long-day photoperiod. Under the impact of strong frost, photochemical efficiency was strongly inhibited in both sets of plants. The reduction in photosynthetic performance during winter was accompanied by a pronounced decrease in the content of chlorophyll and of several chlorophyll-binding proteins [light-harvesting complex (LHC)IIb, LHC Ib, and a chlorophyll-binding protein with MW 43 kDa (CP 43)]. This observed seasonal decrease in photosynthetic pigments and in pigment-binding proteins was irrespective of the degree of frost hardiness and was apparantly under the control of the length of the daily photoperiod. Under a constant 9-h daily photoperiod the chlorophyll content of the needles was considerably lower than under long-day conditions. Transfer of the trees from short-day to long-day conditions resulted in a significantly increased chlorophyll content, whereas the chlorophyll content decreased when trees were transferred from a long-day to a short-day photoperiod. The observed changes in photosynthetic pigments and pigment-binding proteins in Scots pine needles are interpreted as a reduction in the number of photosynthetic units induced by shortening of the daily light period during autumn. This results in a reduction in the absorbing capacity during the frost-hardened state.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004250050246
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  • 2
    Digitale Medien
    Digitale Medien
    Frost hardening and photosynthetic performance of Scots pine (Pinus sylvestris L.). II. Seasonal changes in the fluidity of thylakoid membranes (1998)
    Springer
    Planta 204 (1998), S. 201-206 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Key words: Electron paramagnetic resonance ; Frost hardening ; Membrane fluidity ; Photoperiod ; Scots pine ; Thylakoid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract. The fluidity of chloroplast thylakoid membranes of frost-tolerant and frost-sensitive needles of␣three- to four-year-old Scots pine (Pinus sylvestris L.) trees, of liposomes produced from the lipids of the thylakoids of these needles, and of liposomes containing varying amounts of light-harvesting complex (LHC) II protein was investigated by means of electron paramagnetic resonance (EPR) measurements using spin-labelled fatty acids as probes. Broadening of the EPR-resonance signals of 16-doxyl stearic acid in chloroplast membranes of frost-sensitive needles and changes in the amplitudes of the peaks were observed upon a decrease in temperature from +30 °C to −10 °C, indicating a drastic loss in rotational mobility. The lipid molecules of the thylakoid membranes of frost-tolerant needles exhibited greater mobility. Moderate frost resistance could be induced in Scots pine needles by short-day treatment (Vogg et al., 1997, Planta, this issue), and growth of the trees under short-day illumination (9 h) resulted in a higher mobility of the chloroplast membrane lipids than did growth under long-day conditions (16 h). The EPR spectrum of thylakoids from frost-tolerant needles at −10 °C was typical of a spin label in highly fluid surroundings. However, an additional peak in the low-field range appeared in the subzero temperature range for the chloroplast membranes of frost-sensitive needles, which represents spin-label molecules in a motionally restricted surrounding. The EPR spectra of thylakoids and of liposomes of thylakoid lipids from frost-hardy needles were identical at +30 °C and −10 °C. The corresponding spectra from frost-sensitive plants revealed an additional peak for the thylakoids, but not for the pure liposomes. Hence, the domains with restricted mobility could be attributed to protein-lipid interactions in the membranes. Broadening of the spectrum and the appearance of an additional peak was observed with liposomes of pure distearoyl phosphatidyl glycerol modified to contain increasing amounts of LHC II. These results are discussed with respect to a loss of chlorophyll and chlorophyll-binding proteins in thylakoids of Scots pine needles under winter conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004250050247
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  • 3
    Digitale Medien
    Digitale Medien
    Growth and alkaloid contents in leaves of Tabernaemontana pachysiphon Stapf (Apocynaceae) as influenced by light intensity, water and nutrient supply (1996)
    Springer
    Oecologia 107 (1996), S. 160-169 
    Details
    ISSN: 1432-1939
    Schlagwort(e): Monoterpene indole alkaloids ; Tropical trees ; Abiotic factors ; Growth ; C/N balance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The growth of Tabernaemontana pachysiphon (Apocynaceae) plants and the alkaloid content of leaves were investigated in the greenhouse at three levels of nutrient supply under two contrasting water and light regimes. We determined height increment, above-ground biomass production, leaf size, specific leaf weight and the content of the alkaloids apparicine, A2, isovoacangine, tubotaiwine and tubotaiwine-N-oxide. The effects of major controlling factors such as light, water and nutrient supply could be directly correlated with growth and were largely independent of each other. In contrast, leaf-alkaloid contents were influenced by interdependencies among the main factors and individually affected in a synergistic or antagonistic manner which deviated from the effects on growth. The following general trends could be identified with respect to the quantitatively predominant alkaloids apparicine, tubotaiwine and isovoacangine. Increasing nutrient supply had a positive effect on both growth and alkaloid content. Drought increased alkaloid content, but retarded growth. High light intensity lowered alkaloid content but promoted growth. We investigated the relationship between primary production and the production of secondary metabolites with respect to relative and total alkaloid content as well as in relation to the leaves' nitrogen status. Our results showed that under conditions of low nutrient supply, higher proportions of leaf nitrogen were allocated to alkaloids than at moderate or high nutrient supply. Under conditions of drought and low light, all plants allocated almost equal proportions of leaf nitrogen to alkaloids, regardless of fertiliser. Total alkaloid content per plant, however, increased with fertilisation. With respect to the N-allocation strategy, we found no indication of a trade-off between primary production and the production of secondary metabolites in this species. Rather, our results are in accordance with the carbon nutrient balance hypothesis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00327899
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  • 4
    Digitale Medien
    Digitale Medien
    Neurohistologische Untersuchungen an Diseptalgeschädigten Tauben (1939)
    Springer
    Journal of molecular medicine 18 (1939), S. 1416-1417 
    Details
    ISSN: 1432-1440
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01779845
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  • 5
    Digitale Medien
    Digitale Medien
    Konservative und operative Therapie traumatischer Oberarmschaftbrüche (1997)
    Springer
    Der Chirurg 68 (1997), S. 1132-1136 
    Details
    ISSN: 1433-0385
    Schlagwort(e): Key words: Humeral shaft fractures ; Osteosynthesis ; Intramedullary nailing ; Functional bracing. ; Schlüsselwörter: Oberarmschaftbrüche ; Osteosynthese ; Marknagelung ; funktionelle Behandlung.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung. Es wurden 63 Patienten mit einer Oberarmschaftfraktur durchschnittlich 18 Monate nach Unfall sowohl klinisch als auch radiologisch nachuntersucht. 27 Patienten (Gruppe A) wurden operativ und 36 Patienten (Gruppe B) konservativ behandelt. Die Analyse der Ergebnisse nach einem Punktescore nach Kwasny ergab durchschnittlich 6,7 Punkte für Gruppe A und 2,2 Punkte für Gruppe B zu Gunsten des konservativen Vorgehens (p 〈 0,0001; F = 46,9). In den 2 miteinander vergleichbaren Gruppen war die konservative Therapie der chirurgischen Versorgung von Oberarmschaftbrüchen sowohl bzgl. Beweglichkeit von Schulter- und Ellbogengelenk, Kraftminderung, dem Auftreten neurologischer Störungen und von Schmerzen sowie der subjektiven Bewertung der Behandlung und der Kosmetik durch die Patienten überlegen. Die Auswertung der radiologischen Ergebnisse ergab keine Unterschiede (p = 0,48).
    Notizen: Summary. Sixty-three patients with humeral shaft fractures were evaluated clinically and radiographically 18 months after injury; 27 patients were treated surgically (group A) and 36 patients conservatively (group B). Analysis of the results according to a score by Kwasny revealed 6.2 points in group A and 2.2 points in group B (P 〈 0.0001; F = 46.9). The results of these two comparable groups suggest that conservative treatment of humeral shaft fractures is superior regarding mobility of the shoulder and elbow, strength, the incidence of neurological complications, pain, subjective rating and cosmesis. There were no differences on roentgenograms between the two groups (P = 0.48).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s001040050333
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  • 6
    facet.materialart.
    Unbekannt
    Analyzing Historical Count Data: Poisson and Negative Binomial Regression Models (1995)
    Washington D.C., Wash. : Periodicals Archive Online (PAO)
    Historical methods. 28:3 (1995:Summer) 125 
    Details
    ISSN: 0161-5440
    Thema: Geschichte
    URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pao:&rft_dat=xri:pao:article:h347-1995-028-03-000001
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  • 7
    Digitale Medien
    Digitale Medien
    Synthesis and properties of a cellulose exchanger with the crown ether diaminodibenzo-17-crown-5 as anchor group (1995)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 227 (1995), S. 101-110 
    Details
    ISSN: 0003-3146
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Ein Cellulose- Austauscher wurde aus “o-Aminophenol-Cellulose” durch Diazotieren und Kuppeln mit Diaminodibenzo-17-krone-5 hergestellt. Die Verteilungskoeffizienten für Ca2+, Sr2+, Ba2+, Na+ und K+ wurden in Wasser/Methanol-Mischungen als Funktion des Wassergehaltes bestimmt. Die Trennung von Ca2+, Na+ und K+ und die Fraktionierung der Calciumisotope 48Ca und 40Ca wurde untersucht. Der Anreicherungsfaktor ε = 4.9 · 10-3 für 48Ca2+ ist merklich größer als der für Kationenaustauscher mit SO3H-Gruppen gefundene, aber niedriger als der in der Literatur für bestimmte Kryptanden angegebene Wert.
    Notizen: A new cellulose exchanger was synthesized from “o-aminophenolcellulose” by diazotation and coupling with diaminodibenzo-17-crown-5. The distribution coefficients for Ca2+, Sr2+, Ba2+, Na+ and K+ were determined in water/methanol mixtures as a function of the water content. Separation of Ca2+, Na+ and K+ and fractionation of the calcium isotopes 48Ca and 40Ca were investigated. The enrichment factor ε = 4.9 · 10-3 for 48Ca2+ is appreciably higher than that found for cation exchange resins with —SO3H groups, but lower than that reported for certain cryptands.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/apmc.1995.052270110
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