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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 100 (2000), S. 138-144 
    ISSN: 1432-0533
    Keywords: Key words Amyotrophic lateral sclerosis ; Motor neuron disease ; Excitatory amino acid ; Astroglial glutamate transporter ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The spinal cord of 20 patients with amyotrophic lateral sclerosis (ALS) and 5 patients with lower motor neuron disease (LMND) were investigated immunohistochemically using anti-human excitatory amino acid transporter 1 (EAAT1) and EAAT2 antibodies which are the astrocytic transporters. The purpose of the study was to examine relationships between EAAT1 and EAAT2 immunoreactivity and degeneration of anterior horn neurons. Specimens from 20 patients without any neurological disease served as controls. In controls, spinal cord gray matter was densely immunostained by antibodies, whereas the white matter was generally not immunostained. In motor neuron disease (MND) patients, EAAT1 immunoreactivity was relatively well preserved in the gray matter despite neuronal loss of anterior horn cells. On the other hand, EAAT2 immunoreactivity in anterior horns correlated with the degree of neuronal loss of anterior horn cells: in the patients with mild neuronal depletion, anterior horns were densely immunostained by the antibody, whereas in the patients with severe neuronal loss, EAAT2 expression was markedly reduced. Degenerated anterior horn cells frequently showed a much denser EAAT1 and EAAT2 immunoreactivity around the surface of the neurons and their neuronal processes than that observed in normal-appearing neurons. There was no difference in the expression of EAAT1 and EAAT2 immunoreactivity between LMND and ALS patients. These findings suggest that in the early stage of degeneration of anterior horn cells, EAAT1 and EAAT2 immunoreactivity is preserved in the astrocytic foot directly attached to normal-appearing neurons, whereas levels of EAAT1 and EAAT2 protein rather increase in the astrocytic foot directly attached to degenerated anterior horn neurons; the latter effect most probably reduces the elevated glutamate level, compensates for the reduced function of astroglial glutamate transporters, or represents a condensation of EAAT1 and EAAT2 immunoreactivity secondary to loss of neurites and greater condensation of astrocytic processes. Thus, we demonstrate a difference in EAAT1 and EAAT2 immunoreactivity in different stages of progression in ALS, as a feature of the pathomechanism of this disease.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1106
    Keywords: Central cervical nucleus ; Spinocerebellar tract ; Neck muscle afferents ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular and intracellular recordings were made from spinocerebellar tract neurones of the central cervical nucleus (CCN) in C1–C3 segments of the anaesthetized cat. These neurones were identified by antidromic activation from the cerebellar peduncle. Stimulation of the ipsilateral dorsal root elicited extracellular spikes or EPSPs with a monosynaptic latency in almost all CCN neurones in the same segment (segmental input). Late excitatory effects were also observed in about one third of CCN neurones. The monosynaptic EPSP was occasionally followed by an IPSP. The excitatory input from the dorsal root to CCN neurones was extended over several segments for some CCN neurons (extrasegmental input). Monosynaptic excitation was evoked in CCN neurones after stimulation of dorsal neck muscle nerves as well; i.e. splenius (SPL), biventer cervicis and complexus (BCC), rectus capitus dorsalis, and obliquus capitus caudalis. Thresholds for this excitation were near the threshold of the nerve, suggesting that it originated from group I fibres. The component of excitation added after strong stimulation of neck muscle nerves would be attributed to group II fibres. When a CCN neurone received excitatory input from the nerve of one muscle, it was generally not affected by stimulation of other nerves in the same segment. Such muscle specificity of segmental input was the principal pattern of connexion of neck muscle afferents with CCN neurones. In some cases, however, excitatory convergence from SPL and BCC nerves onto single CCN neurones or excitation from the SPL nerve and inhibition from the BCC nerve were also observed. Nearly half of the CCN neurones received input from one muscle nerve of the same segment and not from the afferent of the same muscle of different segments, indicating a segment specificity of input. In the remaining CCN neurones, weaker excitatory effects were induced from afferents of different segments as well. In such extrasegmental effects, inputs to CCN neurones from caudal segments predominated in frequency over those from rostral segments. The origin of extrasegmental input was generally confined to the same muscle. Low threshold muscle afferents from the SPL and BCC were intraaxonally stained with HRP. The collaterals of the stained fibre distributed branchlets and terminals to the CCN, laminae VII, VIII, and motor nuclei. Two fibres responding to local muscle prodding or stretch showed a similar morphology. The findings indicated that muscle spindle afferents from primary endings projected to the CCN.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-1106
    Keywords: Central cervical nucleus ; Spinocerebellar tract ; Cerebellum ; Spinal cord ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spinocerebellar tract (SCT) neurones in and around the central cervical nucleus (CCN) were physiologically identified by antidromic activation of these cells on stimulation of the cerebellum. Among the Spinocerebellar tract cells thus identified, those ascending the contralateral spinal funiculi were found in the CCN and ventralwards, whereas those ascending the ipsilateral funiculi existed mostly dorsal to the CCN partly overlapping with crossed cells in the nucleus. Mapping sites from which CCN cells were antidromically activated showed that axons of the CCN-SCT cross at the same segment, ascend the ventral funiculus initially, the lateral funiculus at rostral C1 and the lateral border of the medulla to reach the cerebellar peduncle, enter the cerebellum mainly via the restiform body but possibly also via the superior peduncle. Systematic mapping of stimulation within the cerebellum indicated that the CCNSCT projects to the medial part of the anterior lobe and the posterior lobe bilaterally. Projection to lobules I–II was found in almost all CCN-SCT cells examined. Three fourths of CCN-SCT cells projected to the posterior lobe, as revealed by less extensive mapping. Mapping of axonal regions of the same single CCN-SCT cells showed that they project multifocally in the cerebellum, where projection to lobules I–II was common and that to other areas varied with individual cells. Conduction velocites decreased within the cerebellum probably as the result of repeated branching. Mossy fibre responses evoked on stimulation of the C2 dorsal root in cats with the transected dorsal funiculi were shown to be mediated mostly via the CCN-SCT. Mapping the field potential showed that the response was by far the largest in lobules I–II. This suggested that the terminals provided by the CCN-SCT are the densest in these lobules.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 1043-1060 
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: In the absence of emulsifying agents, vinyl acetate polymerization in aqueous media was carried out at 50°C over a wide range of initial initiator and monomer concentrations to clarify the effect of reaction conditions on the kinetic behavior of the polymerization system. It was shown that the rate of polymerization was proportional to reaction time and initiator concentration and independent of the number of polymer particles present. The rate could also be successfully explained by the Smith and Ewart theory for emulsion polymerization when the dissolved monomer in water and the Trommsdorff effect were taken into consideration. A set of equations which could account for the effect of dissolved monomer in water on the rate of polymerization is proposed.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 323-331 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of new polyimides containing fluorinated alkoxy side chains are prepared from novel fluorinated alkoxy diamines. The dieletric constant at 1 kHz in the fluorinated polyimides decreases from 3.3 to 2.6 as fluorine content increases. The refractive index also changes from 1.58 to 1.48, dependent on the fluorine content. In addition, the fluorinated polyimides exhibit lower water absorption than the reference polyimides prepared from m-phenylenediamine.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 24 (1986), S. 249-252 
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 25 (1987), S. 377-382 
    ISSN: 0887-6258
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 2821-2823 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 293-297 
    ISSN: 0887-6266
    Keywords: poly(p-phenylene) from organometallic polymerization, crystal structure of ; crystal structure of poly(p-phenylene) from organometallic preparation ; X-ray diffraction of organometallically produced poly(p-phenylene) ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The two-dimensional crystal structure of poly(p-phenylene) is investigated by linkedatom Rietveld analysis of the x-ray diffraction powder profile. Two molecular chains are packed in a rectangular pgg unit cell (a = 0.779 nm; b = 0.551 nm) with a paracrystalline shift distortion along the chain axis. The molecular conformation is not rigidly planar; rotations between adjacent phenyl-ring planes in a molecule alternate with an angle of about 20°. The setting angle between the mean molecular plane and the a axis is 55.5°.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 637-648 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Blends composed of the α-helical polymers, poly-L-glutamates [(—NHCαHRC′O—)n, R = —CH2CH2COO—(CH2)m(C6H5] (Lm) and the corresponding D enantiomers (Dm), have been studied by x-ray diffraction and viscoelastic measurements. Binary blends of L2, D2, L3, and D3 are compatible and form isomorphous mixed crystals at all compositions, whereas other pairs, with the exception of L1/D1, are incompatible. The demixing process is described for a ternary system consisting of L1, D3, and a diluent chloroform at 40°C. The phase diagram comprises four regions, I, IA, A, and AA, with increasing polymer concentration; I: isotropic, A: anisotropic, IA: I-A biphasic, and AA: A-A biphasic. The IA biphasic gap is greater in the ternary system than in the binary ones. The high-molecular-weight component (D3) is partitioned into the A phase in the IA region. The AA separation originates from incompatibility of the polymers. The phase behavior is discussed on the basis of the Abe-Flory theory by incorporating the polymer-polymer interaction parameter.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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