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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 19 (1974), S. 377-393 
    ISSN: 1432-1106
    Keywords: Frog vestibular neurons ; Dendritic spikes ; Vestibular efferents ; Electrotonic coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Field and intracellular potentials were recorded in the vestibular nuclei of the frog following stimulation of the anterior branch of the ipsilateral vestibular nerve and the spinal cord. The field potential induced by stimulation of the vestibular nerve consisted of an early positive-negative wave followed by a slow negativity and that recorded during spinal cord stimulation was composed of an antidromic potential followed by a slow negative wave. These potentials were most prominent in the ventral region of the stato-acoustic complex. Mono- and polysynaptic EPSPs were recorded from vestibular neurons following vestibular nerve stimulation. Short latency depolarizations of small amplitude preceded the monosynaptic EPSPs in some neurons. Spike-like partial responses were commonly superimposed on the EPSPs. These all-or-none depolarizations probably originated in the dendrites. In a group of vestibular neurons stimulation of the vestibular nerve evoked full action potentials with latencies ranging from 0.2 to 1.1 msec. They are presumably caused by antidromic activation of neurons which send their axons to the labyrinth. The presence of efferent neurons in the vestibular nuclei was confirmed by their successful staining with Procion Yellow following axonal electrophoresis. After stimulation of the spinal cord, antidromic spike potentials and EPSPs were recorded in vestibular neurons. In addition, short-latency depolarizing potentials (EDPs) were evoked by spinal stimulation, with latencies similar to those of antidromic potentials. The EDPs are suggested to be induced by electrotonic transmission from the neighboring cell and likely to be active spike potentials produced at some distance away from the soma.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 20 (1974), S. 223-238 
    ISSN: 1432-1106
    Keywords: Trochlear nucleus ; Interstitial nucleus of Cajal ; Darkschewitsch nucleus ; Descending oculomotor control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Stimulation of both an ipsi and contralateral medial midbrain area in pentobarbital anesthetized cats evoked an EPSP-IPSP sequence in trochlear motoneurons (TMn). The latencies of both the EPSP and IPSP were in the monosynaptic range. Experiments on chronic medial longitudinal fasciculus sectioned cats showed that the TMn effects were not produced by collaterals of ascending vestibular axons antidromically excited from the medial midbrain. Stimulation of the same area had no effect in abducens motoneurons, but produced EPSPs and spikes in reticular neurons just ventral to the VI nucleus. The effective area for producing TMn PSPs, as delimited by multiple stimulation electrode arrays, extended only over the interstitial nucleus of Cajal-nucleus of Darkschewitsch area (IN). The effective bilateral IN areas appeared homogeneous in their ability to produce both the EPSP and IPSP components in TMns, even at minimum stimulus strength. It was concluded that the IN area is the origin of monosynaptic excitatory and inhibitory pathways to TN, and it was discussed how the IN has the synaptology required of an integration center for reciprocal control of conjugate vertical and rotational eye movements.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1365-2222
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background The extent of epithelial injury in asthma is reflected by expression of the epidermal growth factor receptor (EGFR), which is increased in proportion to disease severity and is corticosteroid refractory. Although the EGFR is involved in epithelial growth and differentiation, it is unknown whether it also contributes to the inflammatory response in asthma.Objectives Because severe asthma is characterized by neutrophilic inflammation, we investigated the relationship between EGFR activation and production of IL-8 and macrophage inhibitory protein-1 alpha (MIP-1α) using in vitro culture models and examined the association between epithelial expression of IL-8 and EGFR in bronchial biopsies from asthmatic subjects.Methods H292 or primary bronchial epithelial cells were exposed to EGF or H2O2 to achieve ligand-dependent and ligand-independent EGFR activation; IL-8 mRNA was measured by real-time PCR and IL-8 and MIP-1α protein measured by enzyme-linked immunosorbent assay (ELISA). Epithelial IL-8 and EGFR expression in bronchial biopsies from asthmatic subjects was examined by immunohistochemistry and quantified by image analysis.Results Using H292 cells, EGF and H2O2 increased IL-8 gene expression and release and this was completely suppressed by the EGFR-selective tyrosine kinase inhibitor, AG1478, but only partially by dexamethasone. MIP-1α release was not stimulated by EGF, whereas H2O2 caused a 1.8-fold increase and this was insensitive to AG1478. EGF also significantly stimulated IL-8 release from asthmatic or normal primary epithelial cell cultures established from bronchial brushings. In bronchial biopsies, epithelial IL-8, MIP-1α, EGFR and submucosal neutrophils were all significantly increased in severe compared to mild disease and there was a strong correlation between EGFR and IL-8 expression (r = 0.70, P 〈 0.001).Conclusions These results suggest that in severe asthma, epithelial damage has the potential to contribute to neutrophilic inflammation through enhanced production of IL-8 via EGFR- dependent mechanisms.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 54 (2003), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: We compared functional diversity in 6- to 150-year-old sites on two primary successional glacier forelands (Ödenwinkelkees and Rotmoosferner, Austria) and related these changes to properties of their habitat in the soil (pH, soil organic matter, mineral nitrogen, phosphorus). Comparisons were made with land undisturbed for 9500 years immediately outside the glacier foreland. The functional diversity of the soil microflora was assessed based on microbial processes (N mineralization, ammonium oxidation, arginine deaminase) as well as on the activities of soil enzymes (protease, urease, xylanase, phosphatase, arylsulphatase). On both chronosequences, functional diversity (Shannon diversity index and evenness) and enzyme activity increased up to an age of 50 years, while older soils appeared to have reached a temporary steady state. The values of microbial biomass and enzyme activity were generally smaller in the Ödenwinkel soils than in the Rotmoos sequence, indicating that primary input of carbon from plant growth was less. Functional diversity increased with increasing plant development and organic matter accumulation, explaining similarities in enzyme activity patterns in the sequences. The local climates might also have contributed to the magnitude of the changes. Our data suggest that microbial functional diversity reached stability within 50 years' succession.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 3227-3229 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on gate voltage dependent electron transport in modulation-doped In0.75Al0.25As/In0.75Ga0.25As heterostructures with strained InAs-inserted-channels grown on GaAs substrates. At temperatures of T=4.2 K we achieve mobilities of up to μ=215 000 cm2(V s)−1 and electron densities of nS=1.2×1012 cm−2 for the highest measured gate voltage of Vg=20 V. The electron effective mass m*=0.036 me is determined by temperature dependent Shubnikov–de Haas measurements. The observation of an anisotropic mobility when the first excited subband becomes populated proves interface scattering to be the limiting mechanism for the electron mobility. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 13-15 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A cubic GaN p–n diode has been grown on n-type GaAs (001) substrates by plasma assisted molecular epitaxy. For p- and n-type doping, elemental Mg and Si beams have been used, respectively. The optical properties are characterized by photoluminescence at room temperature and 2 K. Current–voltage and capacitance–voltage measurements of the cubic GaN n+–p junction are performed at room temperature. The electroluminescence at 300 K is measured through a semitransparent Au contact. A peak emission at 3.2 eV with a full width at half maximum as narrow as 150 meV is observed, indicating that near-band edge transitions are the dominating recombination processes in our device. A linear increase of the electroluminescence intensity with increasing current density is measured. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 26 (2003), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Although desiccation tolerant, the resurrection plant Craterostigma plantagineum is sensitive to relatively low levels of sodium chloride. Exposure to sodium chloride, but not dehydration, led to accumulation of sodium ions in leaves and roots and caused irreversible wilting. The effects of salt and dehydration on transcript accumulation patterns were studied by using selected cDNA clones that were related to water stress. Most of the clones represented genes that were up-regulated in response to both treatments. Among the transcripts specifically up-regulated by dehydration were RNAs encoding transcripts with homology to aquaporins. Expression analysis revealed dehydration-specific profiles of late embryogenesis abundant (LEA) genes, which differed from the patterns observed for the same genes under sodium chloride stress. The interconversion of octulose and sucrose, which is characteristic for the desiccation/rehydration cycle in C. plantagineum leaves, was not activated by sodium chloride. The present results suggest that dehydration-specific responses involve the synchronized expression of specific genes and the presence of a determined concentration of sucrose. These dehydration responses were not detected in response to sodium chloride treatment.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 26 (2003), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Verbascose, the pentasaccharide of the raffinose family of oligosaccharides, consists of galactose units joined to sucrose. In pea (Pisum sativum) seeds, the content of verbascose is highly variable. In a previous study on a high-verbascose pea cultivar, the present authors have demonstrated that verbascose is synthesized by a multifunctional stachyose synthase (EC 2.4.1.67), which utilizes raffinose as well as stachyose as a galactosyl acceptor. Herein the results of a study of the cloning and functional expression of stachyose synthase from the low-verbascose genotype SD1 are reported and it is demonstrated that this line contains a protein with a reduced ability to synthesize verbascose. Analysis of seeds from seven pea lines revealed a positive correlation between verbascose synthase activity and verbascose content. Among these genotypes, only the SD1 line showed low verbascose synthase activity when the data were normalized to stachyose synthase activity. These results suggest that differences in the level of verbascose synthase activity could be caused by mutations in the stachyose synthase gene as well as by variation in the amount of the protein. The lines were also analysed for activity of α-galactosidase, a catabolic enzyme that could limit the extent of verbascose accumulation. No relationship was found between α-galactosidase activity and the amount of raffinose family oligosaccharides.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 26 (2003), S. 0 
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The current carbon supply status of temperate forest trees was assessed by analysing the seasonal variation of non-structural carbohydrate (NSC) concentrations in leaves, branch wood and stem sapwood of 10 tree species (six deciduous broad-leafed, one deciduous conifer and three evergreen conifer trees) in a temperate forest that is approximately 100 years old. In addition, all woody tissue was analysed for lipids (acylglycerols). The major NSC fractions were starch, sucrose, glucose and fructose, with other carbohydrates (e.g. raffinose and stachyose) and sugar alcohols (cyclitols and sorbitol) playing only a minor quantitative role. The radial distribution of NSC within entire stem cores, assessed here for the first time in a direct interspecific comparison, revealed large differences in the size of the active sapwood fraction among the species, reflecting the specific wood anatomy (ring-porous versus diffuse-porous xylem). The mean minimum NSC concentrations in branch wood during the growing season was 55% of maximum, and even high NSC concentrations were maintained during times of extensive fruit production in masting Fagus sylvestris. The NSC in stem sapwood varied very little throughout the season (cross species mean never below 67% of maximum), and the small reductions observed were not significant for any of the investigated species. Although some species contained substantial quantities of lipids in woody tissues (‘fat trees’; Tilia, Pinus, Picea, Larix), the lipid pools did not vary significantly across the growing season in any species. On average, the carbon stores of deciduous trees would permit to replace the whole leave canopy four times. These data imply that there is not a lot of leeway for a further stimulation of growth by ongoing atmospheric CO2 enrichment. The classical view that deciduous trees rely more on C-reserves than evergreen trees, seems unwarranted or has lost its justification due to the greater than 30% increase in atmospheric CO2 concentrations over the last 150 years.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Scandinavian journal of immunology 3 (1974), S. 0 
    ISSN: 1365-3083
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A simple procedure for covalent coupling of polysaccharides (PS) to erythrocytes for passive hemagglutination is described. The PS is dissolved in saline and activated by adding cyanogen bromide, keeping the pH at 10.7. After adjusting the pH to 7.8, the activated PS solution is admixed to a 2% erythrocyte suspension for coupling, for 2 hr. Using dextran fractions for coupling, such sensitized cells show a high degree of specific sensitivity, similar to that produced by contact with stearoyl-dextran. Another PS, guaran, was similarly coupled to erythrocytes, conferring on them a high degree of specific sensitivity.
    Type of Medium: Electronic Resource
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