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  • 11
    Electronic Resource
    Electronic Resource
    Electron transport is the functional limitation of photosynthesis in field-grown Pima cotton plants at high temperature (2004)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 27 (2004), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Restrictions to photosynthesis can limit plant growth at high temperature in a variety of ways. In addition to increasing photorespiration, moderately high temperatures (35–42 °C) can cause direct injury to the photosynthetic apparatus. Both carbon metabolism and thylakoid reactions have been suggested as the primary site of injury at these temperatures. In the present study this issue was addressed by first characterizing leaf temperature dynamics in Pima cotton (Gossypium barbadense) grown under irrigation in the US desert south-west. It was found that cotton leaves repeatedly reached temperatures above 40 °C and could fluctuate as much as 8 or 10 °C in a matter of seconds. Laboratory studies revealed a maximum photosynthetic rate at 30–33 °C that declined by 22% at 45 °C. The majority of the inhibition persisted upon return to 30 °C. The mechanism of this limitation was assessed by measuring the response of photosynthesis to CO2 in the laboratory. The first time a cotton leaf (grown at 30 °C) was exposed to 45 °C, photosynthetic electron transport was stimulated (at high CO2) because of an increased flux through the photorespiratory pathway. However, upon cooling back to 30 °C, photosynthetic electron transport was inhibited and fell substantially below the level measured before the heat treatment. In the field, the response of assimilation (A) to various internal levels of CO2 (Ci) revealed that photosynthesis was limited by ribulose-1,5-bisphosphate (RuBP) regeneration at normal levels of CO2 (presumably because of limitations in thylakoid reactions needed to support RuBP regeneration). There was no evidence of a ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) limitation at air levels of CO2 and at no point on any of 30 A–Ci curves measured on leaves at temperatures from 28 to 39 °C was RuBP regeneration capacity measured to be in substantial excess of the capacity of Rubisco to use RuBP. It is therefore concluded that photosynthesis in field-grown Pima cotton leaves is functionally limited by photosynthetic electron transport and RuBP regeneration capacity, not Rubisco activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.2004.01171.x
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  • 12
    Electronic Resource
    Electronic Resource
    Axial and radial pressure exerted by earthworms of different ecological groups (1999)
    Springer
    Biology and fertility of soils 29 (1999), S. 262-269 
    Details
    ISSN: 1432-0789
    Keywords: Keywords Axial pressure ; Earthworms ; Ecological groups ; Radial pressure ; Burrowing activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The aim of this study was to measure the pressures exerted by earthworms during burrowing. For this purpose we developed two methods with which to quantify the axial and radial pressure. The data were recorded with an electronic balance that was connected to a PC. Artificial earthworm burrows were used to standardize the measurements. Plexiglas tubes with diameters ranging from 2 to 6.3 mm which corresponded to the diameter of the earthworms were used. A pin was placed inside the tubes, on which the earthworms exerted a pressure by peristaltic locomotion. Only the maximum values of the pressure measurement were taken into account for evaluation, and the arithmetic mean was calculated. The measurements were conducted with Aporrectodea longa, Lumbricus terrestris, Aporrectodea caliginosa, Octolasion cyaneum, Allolobophora chlorotica, Aporrectodea rosea, Lumbricus rubellus and Dendrobaena octaedra. The species examined were classified into ecological groups. The mean axial pressures exerted by each group were in the order: epigeic (14–25 kPa), endogeic (27–39 kPa) and anecic (46–65 kPa). For the mean radial pressure the order was: epigeic (39–63 kPa), anecic (72–93 kPa) and endogeic (59–195 kPa). It was apparent from the results that radial pressure is the most important pressure with respect to the burrowing activity of earthworms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050551
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  • 13
    Electronic Resource
    Electronic Resource
    Determination of phenolic compounds in waste water by solid-phase micro extraction (1997)
    Springer
    Fresenius' journal of analytical chemistry 357 (1997), S. 326-332 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The solid-phase micro extraction technique (SPME) using a polyacrylate coated fibre has been examined with the aim to determine phenolic components in strong contaminated waste water. Considering the high contents and the great variety of accompanying organic material, the feasibility of SPME-GC-MS analysis has been tested. In this connection the influence of matrix components on the SPME results are discussed. EPA-604 phenols and some other phenolic components have been sampled by a polar fibre under standard conditions and in original waste water. The effects of defined concentrations of humic acids and surfactants on the recovery of phenols have been studied. The influence of other organics, e.g. hexachlorocyclohexane isomers, on the recoveries of phenols are discussed. Finally, a comparison between results of a liquid-liquid extraction and SPME describes the performance of SPME regarding the phenol analysis of strong-loaded water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050162
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  • 14
    Electronic Resource
    Electronic Resource
    Der M. orbicularis oculi bei einigen Laboratoriumstieren (Ratte, Kaninchen, Meerschweinchen) (1954)
    Springer
    Graefe's archive for clinical and experimental ophthalmology 155 (1954), S. 213-226 
    Details
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Ausgehend von verschiedenen, funktionellen Überlegungen, daß der M. orbicularis oculi kein reiner Ringmuskel sein kann, wird beim Meerschweinchen, Kaninchen und bei der Ratte der Muskel als ein kompliziertes System mit funktioneller Struktur erkannt. Dieses Orbicularissystem ist bei den untersuchten Arten verschieden aufgebaut, läßt jedoch einen ähnlichen, funktionellen Grundplan erkennen. Die Ober- und Unterlidmuskulatur bildet keine parallelfaserigen, zirkulären oder elliptischen Bögen, sondern gitterartig, sich in der Lidmitte durchkreuzende Faserzüge, die in gleicher Anordnung bis an die Haut weiterlaufen. Dieses Scherengitter kann sich bei den Lidbewegungen verstellen und die Haut mit ihren Anhangsorganen gleichmäßig mitführen. Die Orbiculariszüge sind im Bereich der Lidwinkel fixiert, wo sich zwar die Bündel stoffartig durchflechten, aber durch radiäre Bänder (Ratte), durch radiärhorizontale Muskelzüge (Mm. retractores) (Kaninchen) oder durch horizontale Zwischensehnen und Mm. retractores (Meerschweinchen) bis zu einem gewissen Grade festgestellt sind. Auf diese Weise können sich die Orbicularisbögen der Lider bei der Kontraktion abflachen, so daß die Spaltform des Lidapparates erhalten bleibt. Beim Meerschweinchen wird außerdem ein eigener Muskel für die Tarsaldrüsen beschrieben, der wahrscheinlich für die Sekretionsförderung eine Rolle spielt („M. glandulae tars.”).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00682188
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  • 15
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Matrixmorphologie von phenolharzgebundenen Cellulosepapier-Schichtpreßstoffen (1990)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 41 (1990), S. 273-279 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: By transmission electron microscopy, globular structures were observed on the fracture surface of the phenolic resin matrix. From water diffusion experiments the existence of a layer between the globules with a lower network density can be deduced. When the resin is modified by NBR or by tung oil combined with tricresyl phosphate, two separated phases are indicated by dynamic mechanical analysis, by thermally stimulated depolarization measurements, and by TEM.
    Notes: Auf Matrixbruchflächen werden mittels Transmissionselektronenmikroskopie globulare Strukturen beobachtet. Aus Untersuchungen zur Wasserdiffusion kann auf eine Zwischenschicht mit geringerer Vernetzungsdichte geschlossen werden. Ist die Harzmatrix mit NBR-Kautschuk oder mit Holzöl in Kombination mit Tricresylphosphat modifiziert, so weisen die dynamisch-mechanische Analyse, Messungen der thermisch stimulierten Depolarisation und TEM-Untersuchungen auf zwei separierte Phasen hin.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1990.010410503
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  • 16
    Electronic Resource
    Electronic Resource
    Colourless, transparent conductive polymer films with ultrathin networks of organic crystals (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 6 (1996), S. 330-334 
    Details
    ISSN: 1057-9257
    Keywords: conductive composites ; organic metals ; BEDO-TTF ; nanocrystals ; polymer composites ; optical properties ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The possibilities of increasing the transparency of conductive organic polymeric composites obtained by growing crystalline conductive networks in situ are discussed and new methods of preparation of practically colourless conductive polymer films are presented. We show that in most cases the colour which appears during the preparation of a conducting composite by reticulate doping is not directly related to the conducting network, which usually consist of relatively well-formed microcrystals, but results instead from the additive molecules present in the polymer matrix as less organised aggregates or a molecularly dispersed phase. By an appropriate choice of preparation conditions or electrochemically one can get rid of the strongly absorbing part of the complex so that the absorption in the visible range can be substantially reduced without losing conductivity and without deterioration of the conductive network.These phenomena are demonstrated on polycarbonate with fine networks of BEDO-TTF iodine and bromine salts obtained by casting or spin coating in order to obtain thin homogeneous films, e.g. to prepare electrodes for electro-optical investigations. Transparent, colourless conductive films 20-2 μm thick (surface resistivity of the order of 103-104 Ω/□) have been obtained and the structure of the conductive networks in these materials, their optical properties in the visible and near-infrared range as well as their electrical properties are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Autostimulatory mechanisms in myeloid leukemogenesis (1987)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 34 (1987), S. 39-46 
    Details
    ISSN: 0730-2312
    Keywords: c-myb rearrangement ; granulocyte-macrophage colony-stimulating factor ; panspecific hemopoietin ; interlcukin-3 ; autostimulation ; myeloid leukemia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: WEHI-274 is a monocytic leukemia that arose in a BALB/c mouse infected with Abelson murine leukemia virus. A series of subclones were derived from early passages of this tumor. Three subsets of these leukemogenic subclones were identified. Two subsets demonstrated autostimulatory patterns of growth. This was due to the ectopic production of the T-cell lymphokine the panspecific hemopoietin IL-3 in one case and of the T-cell lymphokine granulocyte-macro-phage colony-stimulating factor (GM-CSF) in the other. The third type of subclone did not secrete any autostimulatory growth factor. In the subclone producing IL-3, one copy of IL-3 gene was rearranged and abnormal IL-3 RNA transcripts were present in the nucleus. Subclones producing GM-CSF also contained abnormal GM-CSF RNA transcripts, although no rearrangement of the GM-CSF gene was detected. All three sets of subclones shared a common rearrangement of one c-myb oncogene, suggesting that they share a common ancestor. These results suggest that initiation or progression of leukemogenic behavior in this abnormal clone occurred in three different ways, two of which involved autostimulation by the ectopic activation of T-cell lymphokine genes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240340106
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