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  • 1
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Muon electron pairs were detected in an Al multiplate spark chamber, exposed to a neutrino beam from the CERN PS. The leptons were not accompanied by other particles, except occasionally by protons. The background came mainly from muon associated π0 production, with one decay gamma lost. It was determined empirically, together with the small contribution from υ e reactions. For electron energies above 2 GeV the background is 5.7±1.5 events, whereas 18 (μe)-candidates have been observed. Hence the effect is established, with a rate of about 10−4 as compared to the muonic reactions above 3 GeV. Charm creation as the origin of this (μe)-production process is excluded; heavy neutral lepton production does not fit the kinematics observed. Instead the events are compatible with the two-body decay of an object with variable invariant mass of order 1 GeV, possibly resulting from axion interactions.
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  • 2
    ISSN: 1432-1335
    Keywords: Tobacco-specific N-nitrosamines ; N′-nitrosonornicotine (NNN) ; 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) ; N′-nitrosoanatabine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tobacco and tobacco smoke contain relatively high amounts of four tobacco-specific N-nitrosamines. Of these, N-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), and N′-nitrosoanatabine (NAT) were bioassayed at three dose levels by subcutaneous injections into male and female F344 rats in 60 subdoses amounting in total to 9, 3, and 1 mmol/kg. Compared with the solvent control group (trioctanoin), both NNN and NNK induced significant numbers of tumors of the nasal cavity (P〈0.01) at all three dose levels in both male and female rats. Significant numbers of tumors were also induced by NNK in the lung at all three dose levels and in the liver at the highest dose level (P〈0.05). In addition to nasal tumors NNN also induced esophageal tumors at a significant rate in male rats at the high and medium dose levels and in female rats at the high level (P〈0.05); NAT was inactive at the three doses tested. Bioassays at lower dose levels as well as biochemical studies are strongly indicated for NNN and NNK since these nitrosamines occur in relatively high amounts in both chewing tobacco and tobacco smoke.
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  • 3
    ISSN: 1432-1335
    Keywords: Betel quid chewing ; Saliva ; Areca-derived N-nitrosamines ; Tobacco-specific N-nitrosamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Betel quid chewing is strongly associated with cancer of the oral cavity, especially when tobacco is added to the quid. It is our working hypothesis that, during chewing, Areca-derived N-nitrosamines are formed and, in the presence of tobacco, Nicotiana-specific N-nitrosamines are formed as well and further that these agents may contribute to the high risk of oral cancer in betel-quid chewers. This preliminary report presents our finding of N-nitrosoguvacoline in the saliva of betel-quid chewers (2.2–350 ppb). When the quid contains tobacco, the tobacco-specific N-nitrosamines, N′-nitrosonornicotine (1.2–38.3 ppb), N′-nitrosoanatabine (3.2–39.5 ppb), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (1.0–2.3 ppb) are also found in the saliva.
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  • 4
    ISSN: 1435-702X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Serial examinations of rabbit eyes at different times following intravenous injections of a blastospore suspension of Candida albicans were performed. All histological findings in PAS stained slides demonstrate that the microorganisms reach the eye via the ciliary arteries and infection starts primarily in the choroid. Here the outpoured leukocytes are soon replaced by histocytic cell formations. The fungi break into the retina through Bruch's membrane followed by these inflammatory cells. In contrast to this there is a conspicuous absence of blastospores in and around the retinal vessels. The retina's lack of primary involvement is of great advantage to the function of the eye as the uvea has all defense mechanisms available to combat the invaders. Our results show that there are apparently particular ways of blood supply to the retinal circulation.
    Notes: Zusammenfassung An Hand von histologischen Befunden, die bei Serienuntersuchungen von Kaninchenaugen nach intravenöser Injektion von Candida albicans-Suspensionen zur Beobachtung kamen, konnte gezeigt werden, daß die Einschleusung der Keime über die Ciliararterien erfolgt und die Infektion primär in der Aderhaut beginnt. Hier bilden sich nach einer vorübergehenden Ausschüttung von polymorphkernigen Leukocyten histiocytäre Granulome. Die Pilze wandern, gefolgt von den Entzündungszellen, durch die Bruchsche Membran in die Retina ein. In den Netzhautgefäßen finden sich hingegen praktisch nie Blastosporen. Für den Bestand des Auges ist dieser Weg, der die Netzhaut offensichtlich weitgehend verschont, von entscheidendem Vorteil, da in der Chorioidea alle Defensivkräfte mobilisiert werden können, die letzten Endes die Zerstörung der eingedrungenen Erreger bewirken.
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