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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 88 (1994), S. 222-227 
    ISSN: 1432-0533
    Keywords: Key words Amyotrophic lateral sclerosis ; Anterior horn neuron ; Synapse ; Active zone ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report deals with an ultrastructural investigation of the synapses of anterior horn neurons in the lumbar spinal cords of five patients with amyotrophic lateral sclerosis (ALS) who had mild neuronal depletion. Specimens from five age-matched, neurologically normal individuals served as controls. In each instance, the autopsy was performed within 3 h after death. A statistically significant decrease in cell body area, number of synapses and total synaptic length was found in the normal-appearing neurons of the ALS patients. The alterations were more pronounced in neurons with central chromatolysis. However, despite an approximately 20  % reduction in the number of synapses, the length of the active synaptic zone of the normal-appearing neurons in the ALS patients was not diminished. This observation may be accounted for by a plasticity to the loss of synapses which maintained the active zone of the remaining synapses to increase synaptic efficiency. It is suggested that when the plasticity of the active zone reaches its limit, the continuing loss of synapses may lead to functional impairment. The capacity of the active synaptic zone to respond to progressive denervation of the anterior horn neurons may preserve motor function or slow the development of motor deficits in the early stage of degeneration of the lower motor neurons.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 97 (1999), S. 463-468 
    ISSN: 1432-0533
    Keywords: Key words Amyotrophic lateral sclerosis ; β-Amyloid precursor protein ; Immunohistochemistry ; Fast axonal transport ; Anterior horn neuron
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We investigated the localization and extent of β-amyloid precursor protein (β-APP695) immunoreactivity as a sensitive marker for impairment of fast axonal transport in the spinal cords of 21 patients with amyotrophic lateral sclerosis (ALS), paying special attention to anterior horn neurons. Specimens from 18 patients without neurological disease served as controls. Increased β-APP immunoreactivity was frequently recognized in the anterior horns of the ALS patients with short clinical courses or with mild depletion of anterior horn cells, while no β-APP immunoreactivity was demonstrated in those with severe depletion of anterior horn neurons or with long-standing clinical courses. Increased β-APP immunoreactivity in the anterior horn neurons was mainly confined to the perikarya and no immunoreactivity was recognized in the dendrites or proximal axons directly emanating from the somata, except some spheroids (proximal axonal swellings) which showed increased immunoreactivity of β-APP. Increased β-APP immunoreactivity was spotted or focally aggregated in the perikarya of normal-looking large anterior horn neurons, while it was frequently diffuse in that of degenerative neurons such as central chromatolytic cells and or those with simple atrophy. On the other hand, the controls showed no immunostaining with β-APP in the spinal cord. These findings suggest that increased immunoreactivity of β-APP in neuronal perikarya of the anterior horn cells and in some proximal axonal swellings is an early change of ALS, and may be a response of the increased synthesis of β-APP resulting from neuronal damage, or the impairment of fast axonal transport.
    Type of Medium: Electronic Resource
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  • 3
    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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  • 4
    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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  • 5
    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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  • 6
    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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  • 7
    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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  • 8
    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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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 27 (1989), S. 1077-1087 
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Structures of poly(alkylene-1,3-benzenedisulfonamide)s [—HN(CH2)mNH—O2SC6H4SO2—]n (PMm: 2 ≤ m ≤ 6) were studied by x-ray diffraction and infrared spectroscopy. The crystal structure of PB6 is monoclinic, space group C2/m—C2h3, with a = 7.70 Å, b = 7.76 Å, c (molecular axis) = 14.1 Å, and β = 117°. Two mirror-image molecules repeating with two monomeric units in an identity period 28.2 Å occupy the same lattice site with equal probability. The alkylene chains assume the planar zigzag conformation, which is the structure isomorphous with PB4. An intermolecular hydrogen bond is formed between each NH group and one of the two O = S groups of the corresponding SO2 unit. The c axis tends to tilt from the fiber axis by an inclination angle of about 3° around the b axis.
    Additional Material: 7 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 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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