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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Microbial ecology 29 (1995), S. 71-81 
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occurrence and distribution of Azorhizobium and Rhizobium strains that induce stem nodulation of Sesbania rostrata were determined in four vegetation zones in Senegal. Based on tests with 16 Rhizobium and 10 Azorhizobium strains nodulating S. rostrata, a method was devised to distinguish among the strains. In all vegetation zones, members of both genera were more abundant in rhizosphere than nonrhizosphere soil under S. rostrata, Cassia obtusifolia, Acacia senegal, and Hystic suaveolens, and Rhizobium was present at higher densities than Azorhizobium. Azorhizobium was more abundant on the leaves and stems than Rhizobium in three of the vegetation zones, and the density of Azorhizobium but not Rhizobium was far greater on the leaves of S. rostrata than the three nonhost species in all four zones. Approximately 90% of the stem nodules and 39–48% of the root nodules on S. rostrata in all four zones were formed by Azorhizobium.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5333-5335 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It is well known that the Cr underlayer plays a critical role in generating large in-plane coercivity in Co-based magnetic thin films. In this paper we report in detail the Co-Sm (1¯100)[0001]//Cr (1¯21¯)[1¯01] epitaxy revealed by high resolution electron microscopy. The lattice mismatch between Co-Sm (1¯100) and Cr (1¯21¯) is less than 2%, suggesting an energetically favorable configuration. The high anisotropy observed in Co-Sm films is discussed by this epitaxial relation. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 3831-3835 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Sm-Co film is a potential candidate for the future high density recording media of 10 Gb/in2 which requires bit sizes of the order of 300 nm and grain sizes of about 10 nm. This article investigates the microstructure of the Cr underlayer in Sm-Co thin films and its effect on Sm-Co thin films prepared by the dc magnetron sputtering technique. The grain size of the Cr underlayer is found to be about 25 nm. Grains with small angle misorientation usually form local agglomerates. Studies by transmission electron microscopy (TEM) bright field images at different defocus settings and by high resolution electron microscopy indicate that a large proportion of the grain boundaries have gaps. The gap width (about 1–3 nm) varies from place to place. The Sm-Co films deposited on the Cr underlayer inherit similar gaps at positions adjacent to the grain boundary gaps of the Cr underlayer. Such gaps produce grain-like contrast of about 25 nm in TEM bright field images. However, such contrast becomes weak as the thickness of the film increases and disappears at a thickness of 96 nm, suggesting the gaps are sealed at places far from the Cr underlayer. The effect of the Cr underlayer on magnetic properties are discussed. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    Recall 7 (1995), S. 66-68 
    ISSN: 0958-3440
    Source: Cambridge Journals Digital Archives
    Topics: Linguistics and Literary Studies , Computer Science
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 53 (1997), S. 568-570 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary.  This paper presents a summary of the recommendations that were formulated for the purposes of unifying the nomenclature for hepatitis C virus (HCV), based upon guidelines of the International Committee on Virus Taxonomy (ICTV), and provides guidelines of the incorporation of sequence data into an HCV database that will be available to researchers through the internet. Based upon the available data, the genus Hepacivirus should be regarded as comprising as comprising a single species with HCV-1 as the prototype. All currently known isolates of HCV can be divided into six phylogenetically distinct groups, and we recommend that these groups are described as clades 1 to 6. Whether or not these should be regarded as different species within the Hepacivirus genus requires additional clinical, virological, and immunological information. Clades 1, 2, 4, and 5 would correspond to genotype 1, 2, 4, and 5 while clade 3 would comprise genotype 3 and genotype 10, and clade 6 comprise genotypes 6, 7, 8, 9, and 11. We propose that existing subtype designations are reassigned within these clades based upon publication priority, the existence of a complete genome sequence and prevalence. The assignment of isolates to new clades and subtypes should be confined to isolates characterized from epidemiologically unlinked individuals. Comparisons should be based on nucleotide sequence of at least two coding regions and preferably of complete genome sequences, and should be based on phylogenetic analysis rather than percent identity. A forum for discussion and contributions to these recommendations will be made available at the international HCV database at http://s2as02.genes.nig.ac.jp.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1750
    Keywords: Key words: Antibody—Surfactant protein A—Group B streptococci—Pneumonia.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Surfactant protein A (SP-A) increases the resistance of surfactant to inhibition by plasma and other proteins. In a previous study we found that a monoclonal anti-SP-A antibody (R 5) increased the sensitivity of surfactant to inhibition by fibrinogen in vivo and in vitro. SP-A has been shown to stimulate microbial phagocytosis and killing by alveolar macrophages. We hypothesized that using R 5 to inactivate SP-A in an animal model mimicking congenital group B streptococcal (GBS) pneumonia might result in increased bacterial proliferation and a deterioration in lung function. Newborn near term rabbits were delivered by Cesarean section, anesthetized, tracheotomized, and ventilated for 5 h in a plethysmograph system allowing measurement of dynamic lung-thorax compliance. Postnatally the animals received one intratracheal injection (5 ml/kg) of R 5, nonspecific IgG, or normal saline. At 30 min all animals received a standard dose of an encapsulated GBS strain by intratracheal injection. The number of bacteria (mean log10 CFU/g lung ± S.D.; CFU = colony forming unit) was evaluated in lung homogenates. Histologic lung sections were judged by light microscopy. Bacterial proliferation was similar in rabbits treated with the monoclonal antibody (9.33 ± 0.39; n= 14) and in control animals receiving saline (9.16 ± 0.35; n= 14) or nonspecific IgG (9.26 ± 0.31; n= 11). No significant differences were noted on the histologic analysis or in measurements of lung function. We conclude that intratracheal instillation of a monoclonal anti-SP-A antibody did not increase bacterial proliferation in GBS-infected newborn rabbits. These findings suggest that SP-A does not play an important role in protection against encapsulated GBS strains in the neonatal period.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-2013
    Keywords: Key words Voltage-gated potassium currents ; Potassium channel ; β-Subunits ; Xenopus oocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We have examined the effects of co-expression of Kvβ1.1 and Kvβ2.1 subunits on the gating of rat brain Kv1.4 channels, expressed in Xenopus oocytes. Expression of Kv1.4 subunits alone produced a rapidly inactivating ”A” type current, which activated at potentials beyond –60 mV in a solution containing high levels of rubidium. Current activation curves obtained from tail current measurements were fitted with a Boltzmann function, with V 1/2 = –47 mV and k = 10 mV. Neither the Kvβ1.1 nor Kvβ2.1 subunits altered the voltage dependence of activation. Both subunits accelerated the activation time constant of Kv1.4, without affecting its voltage dependence. Surprisingly, the Kvβ2.1 subunit, which lacks an N-terminal inactivation domain, was almost as effective as the Kvβ1.1 subunit in speeding up Kv1.4. Steady-state inactivation of Kv1.4 was unchanged upon co-expression with either Kvβ1.1 or Kvβ2.1 subunits. Kv1.4 recovered from inactivation with two time constants; apart from an ≈ 50% lengthening of the slow time constant with a high Kvβ2.1 injection ratio, neither time constant was altered by either the Kvβ1.1 or Kvβ2.1 subunits, suggesting little interaction with recovery from C-type inactivation. Clearly, β subunits have the potential to modify the gating of Kv1.4 channels in the brain more subtly than has been suggested previously.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 431 (1996), S. 435-442 
    ISSN: 1432-2013
    Keywords: Key words K+ channel gating ; Redox modulation ; Inactivation ; Cloned channel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of cysteine-modifying reagents on the gating of rat cloned Kv1.4 channels expressed in HEK-293 cells were examined using the whole-cell patch-clamp technique. Cells transfected with Kv1.4 expressed a rapidly inactivating K+ current with a mid-point of activation of −31 mV and a slope factor of 5 mV measured with tail current protocols in 35 mM Rb+ external solutions. The cysteine-specific oxidizing agents 2,2′-dithiobis-5-nitropyridine (DTBNP, 50 μM) and chloramine-T (CL-T, 500 μM) removed inactivation of Kv1.4. These effects were reversed by the reducing agent dithiothreitol (DTT, 10 mM). In addition, DTBNP and CL-T also slowed Kv1.4 deactivation and increased the voltage sensitivity of deactivation. The action of cysteine-modifying reagents on Kv1.4 suggests that redox state affects channel gating, with oxidation tending to stabilize the open state of the channel, both by removing inactivation and slowing deactivation.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1433-0474
    Keywords: Schlüsselwörter B-Streptokokken ; Elastase ; Neutrophile Granulozyten ; Pneumonie ; Surfactant ; Key words Group B streptococci ; Neutrophil elastase ; Pneumonia ; Surfactant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: We analyzed the influence of surfactant on inflammatory response, bacterial proliferation and tissue levels of free elastase, a key neutrophil enzyme, in experimental neonatal group B-streptococcal pneumonia. Method: Near-term tracheotomized rabbit fetuses were infected intratracheally with streptococci and ventilated for 5 h. Following the infection the animals received either surfactant (Curosurf 200 mg/kg) or saline (2.5 ml/kg). Controls (n = 11) received only saline. One group of animals (n = 8) was investigated immediately following the injection of bacteria. Results: Surfactant-treated animals demonstrated mitigation of bacterial growth and less marked inflammatory changes on light microscopic examination when compared with infected littermate controls receiving saline. In addition, significantly lower tissue levels of elastase could be demonstrated in the surfactant-treated group (mean ± SEM: 4.22 ± 0.95 vs 8.02 ± 1.28 μg/g lung; p 〈 0.05). Animals treated with saline alone and animals investigated immediately following infection had significantly (p 〈 0.05) lower tissue levels of free elastase in lung homogenate (2.97 ± 0.57 and 2.01 ± 0.45 μg/g lung, respectively). Conclusions: Based on our results we speculate that surfactant plays an important role in the regulation of inflammatory response in neonatal infectious lung disease.
    Notes: Zusammenfassung Fragestellung: Mit Hilfe eines Tiermodells der neonatalen B-Streptokokken-Pneumonie sollte der Einfluß von Surfactant auf das pulmonale Entzündungsgeschehen und die Freisetzung von Elastase, einem proteolytischen Enzym neutrophiler Granulozyten, untersucht werden. Methode: Kaninchenfeten mit einer Tragzeit von 29,5 Tagen wurden intratracheal mit B-Streptokokken infiziert und über einen Zeitraum von 5 h beatmet. 15 min nach der Infektion wurden Surfactant (Curosurf 200 mg/kg) bzw. ein identisches Volumen (2,5 ml/kg) NaCl 0,9 % verabreicht. Im Lungenhomogenisat der linken Lunge wurden die Bakteriendichte bestimmt sowie die Aktivität der freien Elastase gemessen. Die rechte Lunge wurde lichtmikroskopisch im Hinblick auf entzündliche Veränderungen untersucht. Ergebnisse: Die mit Surfactant behandelten Tiere ( n = 11) wiesen ein signifikant niedrigeres Bakterienwachstum, geringer ausgeprägte entzündliche Veränderungen bei der histologischen Beurteilung sowie eine verminderte Aktivität der freien Elastase (Mittelwert ± SEM: 4,22 ± 0,95 vs. 8,02 ± 1,28 μg/g Lunge; p 〈 0,05) im Vergleich zu infizierten Tieren auf, die NaCl erhalten hatten (n = 12). Kontrolltiere, die nur NaCl erhalten hatten (n = 11) und eine weitere Gruppe von Tieren, die unmittelbar nach Infektionsbeginn untersucht wurden (n = 8), zeigten im Vergleich eine signifikant (p 〈 0,05) niedrigere Aktivität der freien Elastase im Lungenhomogenisat (2,97 ± 0,57 bzw. 2,01 ± 0,45 μg/g Lunge). Schlußfolgerungen: Nach Surfactantbehandlung wurden bei experimenteller B-Streptokokken-Pneumonie eine verminderte Bakterienproliferation sowie eine verminderte Freisetzung von Elastase beobachtet. Surfactant scheint somit bedeutsam in die Regulation entzündlicher Vorgänge in der Lunge einzugreifen.
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