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  • 1
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: The ion source for the 1 MW National Spallation Neutron Source (NSNS) is required to provide 35 mA of H− beam current (1 ms pulses at 60 Hz) at 65 keV with a normalized root-mean-square emittance of 〈0.2 pi mm mrad. The same ion source should be able to produce 70 mA of H−at 6% duty factor when the NSNS is upgraded to 2 MW of power. For this application, a radio-frequency driven, magnetically filtered multicusp source is being developed at Lawrence Berkeley National Laboratory. The design of this R and D ion source, which is equipped with a cesium dispenser-collar, a fast ion beam prechopper (rise times 〈100 ns) and a strong permanent-magnet insert for electron deflection, will be presented.© 1998 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 1060-1062 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Heavy ion fusion (HIF) induction accelerators require ion sources that can deliver intense heavy ion beams with low emittance. The typical pulse length is 20 μs with a rise time less than 1 μs and a repetition rate of 10 Hz. So far, the surface ionization sources have been used in most HIF induction linac designs. However, there are other ions of interest to HIF (e.g., Hg, Xe, Rb, Ar, and Ne) which cannot be produced by the surface ionization sources, but rather by volume ion sources. In this paper, we describe an experiment that uses a multicusp source with a magnetic filter to produce beam pulses that have a rise time in the order of 1 μs. By applying a positive biasing pulse on the plasma electrode with respect to the source body, the positive plasma ions can be temporarily repelled from the neighborhood of the extraction aperture, leading to a suppression of the ion beam. As the bias is removed, positive ions flow to the extraction region, enabling a fast-rising beam pulse. The beam current pulses show that there are two distinct groups of ions. An initial fast current rise time (〈2 μs) corresponding to ions originating from within the magnetic filter region followed by a second group of ions with a longer rise time (10–20 μs) originating from the plasma bulk region. Proper positioning of the filament cathode and the magnetic filter field relative to the extraction aperture was found to be critical. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
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  • 3
    facet.materialart.
    Unbekannt
    Minneapolis : Periodicals Archive Online (PAO)
    Philosophical Studies. 80:3 (1995:Dec.) 279-303 
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  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 232 (1971), S. 120-120 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] We used three groups of five cestode-free and nematode-free lambs, 4 weeks old, and eggs of T. ovis which had been collected from experimentally infected dogs and carefully washed with antibiotic solutions. The eggs were artificially hatched and the embryos were activated by Heath's9 method. ...
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 219 (1968), S. 148-148 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Fiji stands well out to sea at the centre of a bathy-metric spiral whose arms are the opposed arc-and-trench systems of the New Hebrides and Tonga10. The oldest rocks in Fiji are strongly deformed and partly metamorphosed volcanic and volcaniclastic early Tertiary strata which are intruded by ...
    Materialart: Digitale Medien
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  • 6
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Oncospheres of T. ovis were chosen as the source of messenger RNA for constructing a cDNA library because they are known to be a rich source of host-protective antigens3'4. Furthermore, in vitro culture techniques5 have shown that hatched and acti-vated T. ovis oncospheres secrete potent ...
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Philosophical studies 80 (1995), S. 279-303 
    ISSN: 1573-0883
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Philosophie
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-1955
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Attempts were made to immunise rats and mice against infection withF. hepatica by oral dosing withT. hydatigena eggs, or by vaccination with variousT. hydatigena antigen preparations. These antigens included extracts fromT. hydatigena cysticerci and cyst fluid, and antigens collected during short-term (48 h) and long-term (14 days) in vitro cultivation of larvae. Immunity was assessed by the numbers ofF. hepatica recovered from the challenge infection in rats, and the mortality rates of infected mice. None of the immunisation regimes withT. hydatigena antigens induced consistent, significant immunity. This was in contrast to the high level of immunity shown by rats dosed orally withF. hepatica metacercariae four weeks prior to challenge infection.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1432-1955
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Twelve dogs were fed mutton containing small sarcocysts, and killed 1, 3, 4, 6, 7, 10, 15, 16, 17 days after infection (DAI). Beginning 13–15 DAI sporocysts 14.7×9.0 μm were passed in the faeces of the dogs killed 15–17 DAI. Histological examination showed that developing stages were most numerous in the subepithelial tissue at the tips of villi in the proximal third of the small intestine. Macrogametes containing tiny PAS+ granules, and microgametocytes with peripheral developing microgametes were present 1 DAI. By 4 DAI oocysts, with a small nucleus and vacuolate cytoplasm were seen. Sporulation was observed 7–10 DAI. The first nuclear division resulted in 2 polar nuclei which divided laterally, resulting in 2 sporocysts each with 2 polar nuclei. This process was repeated once more to produce 4 nucleated sporozoites in each of 2 sporocysts. PAS+ granules were seen at the periphery of sporulating oocysts and sporocysts. There was a large PAS+ granule in the mid zone of sporozoites, with a smaller granule at one tip. Numerous sporulated sporocyst pairs were present beneath the epithelium at the tips of villi in dogs killed during patency. Four lambs were inoculated orally with sporocysts passed by dogs following feeding of infected mutton. Fifteen DAI schizonts were seen in the endothelium of arteries and arterioles in many organs, but not brain. Twenty-four DAI, smaller schizonts were seen in capillary endothelium in many organs, including brain. The two other lambs died 42 and 104 DAI, after an illness characterized by anaemia and ill-thrift. Mature schizonts were found in cells in the brain 42 DAI, associated with nonsuppurative meningoencephalitis. Developing sarcocysts were found in muscle, associated with myositis. Sarcocysts in muscle 104 DAI were mature. In the brain there were degenerate cysts and mature sarcocysts, and nonsuppurative meningoencephalitis.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-1955
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Experiments were carried out to investigate the degree of immunity stimulated againstTaenia taeniaeformis infection in mice by prior administration of eggs or ultrasonically disrupted oncospheres ofT. pisiformis ort. hydatigena. Sonicated oncospheral antigens were given either orally or by subcutaneous injection in Freund's complete adjuvant, and eggs were given orally. Three inbred strains of mice with varying degrees of innate resistance to initial infection withT. taeniaeformis were used in the experiments. These were the moderately resistant BALB/c, moderately susceptible CBA/H, and highly susceptible C3H/He strains. It was found that BALB/c mice developed high levels of immunity when immunised with eitherT. pisiformis orT. hydatigena eggs, or with sonicated oncospheres administered orally or parenterally. CBA/H mice developed moderate immunity, and C3H/He mice generally did not develop a satisfactory level of resistance. The implications of these findings with respect to immunisation of outbred animals against natural infection with larval cestodes using antigens prepared from the oncospheres of heterologous parasite species is discussed.
    Materialart: Digitale Medien
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