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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 4997-5003 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Equiatomic composition powder mixture of pure Fe and B was mechanically alloyed in a controlled atmosphere vibration mill. Amorphous alloy phase formation was established by Mössbauer spectroscopy and by transmission electron microscopy. The variation of the average boron concentration and the homogeneity of the amorphous phase during the alloying process was followed by Mössbauer spectroscopy. At the early stage of the milling process a broad concentration distribution (from 20 to 50 at. % B) was observed. Upon further milling the average B concentration of the amorphous component was gradually enhanced and the concentration heterogeneity decreased. The B concentration of the amorphous phase could be further enhanced by heat treating the milled powder mixture. The highest boron content alloy attained in this study is Fe60B40. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 99 (1995), S. 4447-4450 
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Inorganic chemistry 34 (1995), S. 412-413 
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1440-1770
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography
    Notes: The effect of the insecticide, S-Deltamethrine (DM, LC50 for mosquito larvae: 0.02 ppb), in the concentration range between 0.025 and 2500 ppb was examined in both embryogenesis and embryonic evolution of the electron transport system (ETS) of the bream, roach, barbel and pike. A 0.025 ppb concentration of DM caused 10-25% death of the embryos in the first 2 days of incubation.Fifty per cent of the roach embryos died by the end of a 144 h incubation period when the concentration was 0.025 ppb. In 2.5 ppb, 50% of the embryos died after 120 h. In 25 ppb, 50% death was registered after 96 h, and in 250 and 2500 ppb, 50% death was detected after 48 h. Fifty per cent of the barbel embryos died after a 48 h long incubation time in 250 and 2500 ppb. The same mortality was detected for the embryos of pike in 2500 ppb after a longer (148 and 168 h) incubation time. Half of the bream embryos died after 24 and 48 h at a concentration of 2500 ppb. Larvae showed a more sensitive response to treatments than did embryos. After hatching, 30-84% of the larvae died in 0.025 ppb. Compared to embryos, larvae moved less in a concentration of 0.025 ppb and could not swim as easily as controls. In a concentration 〉0.25-2.5 ppb, larvae were passive and often malformed. S-Deltamethrine inhibited ETS activity in a concentration-dependent manner. Electron transport system activity of larvae was reduced by 50% in 250 ppb concentration.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 269-272 (Jan. 1998), p. 419-424 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 264-268 (Feb. 1998), p. 1255-1258 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    HNO 47 (1999), S. 981-985 
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Stimmfeldmessung ; Myasthenia gravis ; Stroboskopie ; Key words Voice profile ; Myasthenia gravis ; Phoniatrics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The authors have for the first time evaluated the basic parameters of the voice using computed voice analysis in patients with myasthenia gravis (MG). The aim of the study was to introduce an objective method suitable for the assessment of dysphonic symptoms, which predominate in bulbar, oculobulbar and generalized MG. Voice profile studies included the evaluation of the singing voice range, voice dynamics, maximum phonation time, and mean fundamental frequency and intensity during speech. The characteristic of the stroboscopic picture was also determined. Investigations were carried out before and after the intake of Mestinon, a reversible cholinesterase inhibitor, and healthy subjects were used as a control group. In MG, the voice range and dynamics are badly impaired, maximum phonation time is shortened, the mean fundamental frequency during speech is increased, while the intensity is decreased. Mestinon resulted in an improvement in all these parameters, however, they were still impaired in comparison to the control subjects. Most changes were found to be statistically significant. The authors emphasize the role of the otolaryngologist and objective phoniatric methods in the evaluation of MG and other myasthenia-like neurological diseases. The use of these methods for the assessment of phoniatric symptoms in neurological diseases is highly recommended.
    Notes: Zusammenfassung Die Verfasser bestimmten erstmalig die grundlegenden Parameter der Stimme bei Patienten mit Myasthenia gravis (MG) mit Hilfe der modernen Computertonanalyse. Ziel war die Erarbeitung einer objektiven Methode zur Differentialdiagnose der als Leitsymptom auftretenden Phonasthenie der bulbären, okulobulbären bzw. generalisierten MG. Bei der Untersuchung des Stimmfelds wurden der Tonhöhenumfang, Stimmdynamik, Tonhaltedauer, sowie Grundfrequenz und Intensität der Sprechstimme gemessen. Auch die Charakteristika des stroboskopischen Befunds wurden registriert. Die Untersuchungen wurden sowohl ohne Medikamenteinfluß, als auch nach Einnahme von Mestinon (reversibler Cholinesteraseinhibitor), sowie an einer gesunden Kontrollgruppe durchgeführt. Es konnte festgestellt werden, daß der Tonhöhenumfang bei MG-Patienten wesentlich eingeschränkt, die Dynamik stark verringert, der Tonhaltedauer verkürzt, die Sprechstimme erhöht und die Intensität schwächer waren. Nach Gabe von Mestinon waren die Werte zwar besser, erreichten aber nicht die der Kontrollgruppe. Die meisten Veränderungen waren statistisch signifikant. Die Verfasser weisen auf die diagnostische Hilfe hin, die das Verfahren dem HNO-Arzt bei MG und bei anderen, myasthenische Symptome hervorrufenden neurologischen Erkrankungen, leisten kann, und empfehlen eine breitere Anwendung der Methode zur Verifizierung phoniatrischer Symptome bei neurologischen Krankheiten.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0533
    Keywords: Glia ; Motoneuron ; Ribosome ; Spinal cord injury ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Structural changes in lumbosacral ventral horn neurons and their synaptic input were studied at 3, 10, 21, 42, and 90 days following low thoracic cord hemisection in adult rats by light microscopic examination of synaptophysin immunoreactivity (SYN-IR) and by electron microscopy. There was an ipsilateral transient decrease in SYN-IR at the somal and proximal dendritic surfaces of anterior horn neurons which extended caudally from the site of injury over a postoperative (p.o.) period of 42 days. Concomitantly, at 21 days p.o., perineuronal SYN-IR started to recover in upper lumbar segments. By 90 days p.o., a normal staining pattern of SYN was noted in upper and mid lumbar segments, but the perineuronal SYN-IR was still slightly below normal levels in low lumbar and sacral segments. Electron microscopy revealed ultrastructural changes coincident with the alterations in SYN-IR. At 3 days p.o., phagocytosis of degenerating axon terminals by activated microglial cells was observed at the somal and proximal dendritic surfaces of ventral horn neurons. These changes were most prominent up to two segments caudal to the lesion. At 10 days p.o., advanced stages of bouton phagocytosis were still detectable in all lumbosacral motor nuclei. Additionally, abnormal axon terminals, with a few dispersed synaptic vesicles and accumulations of large mitochondria, appeared at the scalloped somal surfaces of anterior horn neurons. At 21 days p.o., several large lumbosacral motoneurons had developed chromatolysis-like ultrastructural alterations and motoneuronal cell bodies had become partially covered by astrocytic lamellae. At 42 days p.o., there was a transient appearance of polyribosomes in some M-type boutons. In addition, at 42 and 90 days p.o., a few degenerating motoneurons were detected in all lumbosacral segments, but most displayed normal neuronal cell bodies contacted by numerous intact synapses as well as by astrocytic processes. In contrast to these striking alterations of synaptic input at somal and proximal dendritic surfaces of motoneurons, relatively few degenerating boutons were detected in the neuropil of motor nuclei at all the p.o. times studied. We suggest that the preferential disturbance of the predominantly inhibitory axosomatic synapses on ventral horn neurons may be involved in the mechanisms which influence the well-established increase in motoneuronal excitability after spinal cord injury.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0533
    Keywords: Key words Glia ; Motoneuron ; Ribosome ; Spinal cord injury ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Structural changes in lumbosacral ventral horn neurons and their synaptic input were studied at 3, 10, 21, 42, and 90 days following low thoracic cord hemisection in adult rats by light microscopic examination of synaptophysin immunoreactivity (SYN-IR) and by electron microscopy. There was an ipsilateral transient decrease in SYN-IR at the somal and proximal dendritic surfaces of anterior horn neurons which extended caudally from the site of injury over a postoperative (p.o.) period of 42 days. Concomitantly, at 21 days p.o., perineuronal SYN-IR started to recover in upper lumbar segments. By 90 days p.o., a normal staining pattern of SYN was noted in upper and mid lumbar segments, but the perineuronal SYN-IR was still slightly below normal levels in low lumbar and sacral segments. Electron microscopy revealed ultrastructural changes coincident with the alterations in SYN-IR. At 3 days p.o., phagocytosis of degenerating axon terminals by activated microglial cells was observed at the somal and proximal dendritic surfaces of ventral horn neurons. These changes were most prominent up to two segments caudal to the lesion. At 10 days p.o., advanced stages of bouton phagocytosis were still detectable in all lumbosacral motor nuclei. Additionally, abnormal axon terminals, with a few dispersed synaptic vesicles and accumulations of large mitochondria, appeared at the scalloped somal surfaces of anterior horn neurons. At 21 days p.o., several large lumbosacral motoneurons had developed chromatolysis-like ultrastructural alterations and motoneuronal cell bodies had become partially covered by astrocytic lamellae. At 42 days p.o., there was a transient appearance of polyribosomes in some M-type boutons. In addition, at 42 and 90 days p.o., a few degenerating motoneurons were detected in all lumbosacral segments, but most displayed normal neuronal cell bodies contacted by numerous intact synapses as well as by astrocytic processes. In contrast to these striking alterations of synaptic input at somal and proximal dendritic surfaces of motoneurons, relatively few degenerating boutons were detected in the neuropil of motor nuclei at all the p.o. times studied. We suggest that the preferential disturbance of the predominantly inhibitory axosomatic synapses on ventral horn neurons may be involved in the mechanisms which influence the well-established increase in motoneuronal excitability after spinal cord injury.
    Type of Medium: Electronic Resource
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