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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 261 (1983), S. 373-374 
    ISSN: 1435-1536
    Keywords: Electron microscopy ; short-time staining ; nodular structure ; crystallization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2307
    Keywords: Mycosis fungoides ; Premycotic lesions ; Parapsoriasis en Plaques ; Langerhans cells ; Virus-like particles ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Skin biopsies of patients with small and large plaque parapsoriasis, premycotic lesions and mycosis fungoides in different stages were examined. Special attention was paid to the relationships between Langerhans cells (LC) and the neighbouring keratinocytes and lymphocytes. At the contact areas of LC and keratinocytes as well as LC and lymphocytes, particular cell membrane phenomena were observed. Aggregations of Langerhans granules and fusions of granules with LC plasma membranes were found exclusively at LC-keratinocyte interfaces. At LC-lymphocyte contact zones cell membrane appositions were seen. In all cases investigated, virus-like particles were mainly ound in LC and indeterminate cells (IDC). In 3 cases lymphocytes also contained these particles. It was of particular interest that virus-like particles were observed in skin specimens of all diseases investigated. Discrimination of these particles from other cellular organelles - especially lysosomes- was difficult, however. The significance of our findings, particularly regarding to the supposed virus aetiology of cutaneous T cell lymphomas, is discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0584
    Keywords: Multiple myeloma-Plasma cell ; Electron microscopy ; Fluorescent antibody technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of “nonsecretory” myeloma is described. The patient had typical osteolytic lesions and marked infiltration of myeloma cells in the bone marrow, and plasma cell leukemia. A good partial remission was obtained with Melphalan, but the patient relapsed and died one year later. Immunofluorescent and immunoelectroscopic studies on the myeloma cells demonstrated the presence of cytoplasmic γ-and κ-chains at the initial stage and of only κ-chains at a relapse. The electron microscopic method for polysome analysis indicated that both L-and H-chains were synthesized on membrane-bound polysomes initially, but the ability to produce H-chain was missing at the relapse.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1335
    Keywords: Murine lymphoma development ; Virus infection ; Thymus ; Reticular epithelial cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report describes two types of reticular epithelial cell in the thymic cortex of the BALB/c mouse, an immature and a mature form. During early stages of lymphoma development, i.e., 2–6 weeks postinfection (p.i.) with Moloney leukemia virus (M-MuLV), activation of the epithelial cells is observed. Although the percentage of these cells in the total cell population of the thymic cortex remains constant during that time, the number of mature epithelial cells is significantly increased in infected animals. Subsequently, about 6 weeks p.i., the number of immature epithelial cells starts to increase, whereas the number of mature reticular epithelial cells declines and the appearance of the mature epithelial cells changes drastically. The results of light and electron microscopic studies indicate degeneration of the mature reticular epithelial cells at the onset of lymphoma development at a time when the first deficiencies in the immunologic competence of the reticular epithelial cells are apparent.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 106 (1983), S. 234-239 
    ISSN: 1432-1335
    Keywords: Osteosarcoma ; Collagen types ; Immunofluorescence microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sixteen cases of typical highly malignant osteosarcoma were investigated by light, electron, and immunofluorescence microscopy to demonstrate the presence of collagen types I–III. It was shown that, in light-microscopically anaplastic areas of the tumor, collagen type III predominates, while only very few membranes of collagen type I are observed. Ultrastructurally, the cells are characterized by numerous free ribosomes in their cytoplasm and only a few membranes of granular endoplasmic reticulum (ER). In osteoblastic areas, collagen type I is increased, while type-III collagen is decreased. The cytoplasm of cells contains markedly more granular ER. An increasing mineralization of matrix is observed. In fibroblastic areas of the tumors, collagen types I and III are codistributed. Tumor cells have a fibroblast appearance with elongated nuclei and well developed granular ER. The chondroblastic areas, characterized by immature neoplastic cartilage, contain varying amounts of collagen type II. Chondroblast-like tumor cells have typical ring-shaped membranes of granular ER in their cytoplasm. The evidence of different collagen types in osteosarcomas lends additional support to the concept that a pluripotent mesenchymal cell is the stem cell of osteosarcomas.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 400 (1983), S. 119-142 
    ISSN: 1432-2307
    Keywords: Thyroid neoplasms ; Hemangioendothelioma ; Electron microscopy ; Factor VIII-related antigen (FVIIIRAG) ; Tumour classification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 65 cases of hemangioendothelioma (HE) of the thyroid were accepted as such after control of slides of surgical or autopsy specimen or both. In a few of the more recent cases material could be examined by electron microscope and in some the search for factor VIII-related antigen (FVIIIRAG) was carried out. The demonstration of Weibel-Palade bodies in tumour cells in two cases and the evidence of FVIIIRAG in tumour cells of at least two cases, including primary tumour and distant metastasis, finally show, that the hemangioendothelioma of the thyroid is not simply an anaplastic carcinoma with some peculiar features; at least some of these tumours are true endotheliomas. The proposal that the term hemangioendothelioma be eliminated from the classification of thyroid tumours is therefore unfounded.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 400 (1983), S. 187-199 
    ISSN: 1432-2307
    Keywords: Malignant fibrous histiocytoma ; Liposarcoma ; Sarcoma ; Soft tissue neoplasms ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural comparison of 7 examples of myxoid malignant fibrous histiocytoma (myxoid MFH) with 6 of myxoid liposarcoma is described. Despite certain histological differences between the two, electron microscopy was more valuable in differentiating MFH from liposarcoma. Electron microscopically, MFH contained a variety of cell types including histiocyte-like, fibroblast-like, intermediate-type, xanthomatous, multinucleated tumor giant cells and undifferentiated cells. Liposarcoma was composed mainly of lipoblasts at various stages of differentiation with a minority of undifferentiated cells and fibroblast-like cells. In contrast to the component cells of the MFH, these lipoblasts were characterized by abundant cytoplasmic glycogen, numerous pinocytotic vesicles and a discontinuous basal lamina in addition to large lipid droplets.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 400 (1983), S. 97-106 
    ISSN: 1432-2307
    Keywords: Tracheobronchial amyloidosis ; Electron microscopy ; Amyloid fibril ; Fibroblast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The author reports on the electron-microscopic examination of the diffuse tracheobronchial amyloidosis of a 51-year-old patient. The amyloid deposits were located in the lamina propria of the tracheal and bronchial mucosa. At the edge of the nodular deposits, condensation and radial arrangement of amyloid fibrils could be seen. Closely connected with the amyloid, active fibroblasts were present and their cytoplasm contained amyloid fibrils. The cell membrane of the fibroblasts was missing in part. Intracellular amyloid fibrils mingled with extracellular deposits. It can be assumed that active fibroblasts play an important role in local amyloid formation.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 59 (1983), S. 295-303 
    ISSN: 1432-0533
    Keywords: Menkes' kinky hair disease ; Brain degeneration ; Mitochondrial abnormalities ; Distribution ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The brain of an autopsy case of Menkes' kinky hair disease (MKHD), after routine histological examination, was studied extensively by electron microscopy, particularly the mitochondrial alterations. There were widespread mitochondrial abnormalities, including enlargement with tubulo-vesiculated cristae, swelling, and dense body formation and occasional accumulation of glycogen within mitochondria, in addition to increased numbers of mitochondria in some neurons. These abnormalities of mitochondria were present in decreasing severity in the following: Purkinje cells, neurons of the molecular and granule cell layers of the cerebellum, and neurons of the cerebral cortex, globus pallidus, lateral nuclei of the thalamus, caudate nucleus, and the myelinated axons in the white matter. This distribution and the degree of mitochondrial abnormalities in the various structures of the brain were compared with those of degenerative lesions in the respective structures. The comparison disclosed that there was a positive correlation between the two. The mitochondrial enlargement and swelling as in the present study had been well documented in the brain of the brindled mouse; mitochondrial dense bodies had also been reported in previous case reports of MKHD by other authors. The present study strongly suggests that the mitochondrial disease is an essential abnormality and may be responsible for the progressive degeneration of the CNS in MKHD.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0533
    Keywords: Human sural nerve ; Electron microscopy ; Myelin sheath thickness ; Internodal length ; Node of Ranvier ; Organic solvents ; Glycogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural and morphometric study was performed on sural nerve biopsies of four industrial spray painters (35–59 years) and 11 controls (6–64 years). No difference could be shown in spray painters and age-matched controls as to the number of myelinated nerve fibres per area, their size distribution, variation of internodal length along single nerve fibres or the ratio between the number of myelin lamellae and the axon circumference. There was marked scattering of the two latter parameters in older exposed and control individuals. The distribution of NADH2-tetrazolium reductase activity was similar in exposed and control cases. The general ultrastructural appearance of nodal-paranodal regions in controls conformed with that noted in experimental animals. The overall ultrastructural organization and age-related changes of nerves of exposed cases were similar to those of control cases except for a presence of paranodal axonal mitochondria which contained glycogen-like particles in exposed cases. In one exposed case abundant dispersed or clustered glycogen-like particles were seen in the paranodal axoplasm. These findings are suggested to be an effect of chronic exposure to organic solvent vapours. Ageing seems, however, to have a much greater impact on the morphology of the sural nerve fibre than occupational exposure to organic solvent.
    Type of Medium: Electronic Resource
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  • 11
    ISSN: 1432-0533
    Keywords: Motor end-plates ; Abnormal differentiation of motor end-plates ; Arthrogryposis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The syndrome of arthrogryposis and palatoschisis (SAP), an inherited syndrome of muscular hypotonia in Charolais cattle, was used as an experimental model to study neuromuscular differentiation. The ultrastructural development of muscle, peripheral nerve, and neuromuscular junctions was studied to determine the sequence of events preceding hypotrophic changes in the skeletal muscles of affected calves at birth. Dorsiflexion of the metatarsophalangeal joints in the hindlimbs occurred in fetuses older than 3 months of age, but hypotrophic changes in skeletal muscle, manifested as small fibers scattered among larger and occasional degenerating fibers, was not apparent until late in gestation, affecting 8-month-old fetuses and neonatal calves. Electron microscope and enzyme histochemistry studies disclosed differentiation of skeletal muscle into fiber types which is consistent with changes expected from disuse and does not indicate a primary myopathic abnormality. Abnormal differentiation of neuromuscular junctions (NMJ), composed of several separated axonal endings terminating in shallow synaptic gutters, indicated impaired maturation of the synapse. The earliest indication of abnormal NMJ was observed in a 5-month-old SAP fetus. The clinical signs and pathologic changes found in the neuromuscular junction and skeletal muscle of SAP fetuses are consistent with an embryologic defect occurring during development of the central nervous system (CNS) that affects the integrated function of the motor neurons to the limbs. However, diversification of myofibers by histochemistry and ultrastructural parameters is evidence that the intrinsic physiologic properties of spinal motor neurons were retained.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 60 (1983), S. 14-18 
    ISSN: 1432-0533
    Keywords: Rathke's cleft cyst ; Craniopharyngioma ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electron-microscopical appearance of a Rathke's cleft cyst is described. The cyst lining is seen to consist predominantly of secretory columnar epithelium, both ciliated and non-ciliated. There are also epidermoid cells occurring singly or in squames. The histogenesis of Rathke's cleft cysts, in relation to craniopharyngiomas, is discussed.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 61 (1983), S. 116-122 
    ISSN: 1432-0533
    Keywords: Methylmercury ; Mitochondria ; Cerebral cortex ; Postnatal development ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neonatal rats received s.c. injections of methymercuric chloride (MeHg) in physiological saline (1.5 mg Hg/kg b.wt.) at 48-h intervals from postnatal day 2 to day 50. Littermate controls were injected with an equivalent volume of saline. All animals were perfused on day 51 and blocks of cerebral cortex were prepared for electron microscopy. Ultrastructural changes in mitochondria were evident in the dendrites, axons and presynaptic terminals of cortical neurones in the MeHg-treated animals. Many mitochondria were condensed with an increased electron density of the inner matrix. Some profiles exhibited regressive alterations, including a disruption of cristae and the inner membrane with an accumulation of electron-opaque material in the matrix. Membranous whorls were found in association with the most degenerate mitochondria. A morphometric analysis of mitochondrial profiles in the neuropil of layer I revealed a 24% decrease in average profile area and a 16% increase in the number of profiles per micrograph in the MeHg-treated animals. These pathological changes in mitochondrial ultrastructure are consistent with an inhibition of mitochondrial respiration. The observed increase in the number of mitochondrial profiles may reflect a compensation by cortical neurons for the reduced efficiency of aerobic metabolism in the individual organelle.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 59 (1983), S. 246-254 
    ISSN: 1432-0533
    Keywords: Muscle spindle ; Electron microscopy ; Terminal nerves ; Denervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intrafusal and extrafusal nerve segments in muscle spindles from tumbricalis muscles of the hind-paw of the rat were studied by electron microscopy from 10h to 5 days after severance of the sciatic nerve. In several spindles examined, nerve fascicles piercing the spindle capsule in the equatorial region contained a large myelinated, a smaller myelinated and an unmyelinated fiber. Unmyelinated fibers were not present in small fascicles leading to the polar region. The changes in the extrafusal nerve segments followed the pattern of Wallerian degeneration. Intra-axonal glycogen deposits were prominent in sensory fibers. The unmyelinated fibers were the earliest to degenerate, the large myelinated ones the latest. Differences between motor and sensory fiber degeneration emerged in their preterminal intrafusal segments and were analogous to those of the nerve endings. Terminal nerve fibers in the spindle equator succumbed to attack of mesenchymal cells, leaving extensive basement membrane reduplications around myelin debris-laden Schwann cells, while polar fibers were engulfed by Schwann cell processes, leaving regular bands of Büngner.
    Type of Medium: Electronic Resource
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 60 (1983), S. 149-152 
    ISSN: 1432-0533
    Keywords: Adrenoleukodystrophy ; Cerebello-brainstem involvement ; Electron microscopy ; Biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of adrenoleukodystrophy was studied morphologically and biochemically. The patient was a 28-year-old man with no family history of adrenoleukodystrophy. His neurologic symptoms were cerebellar ataxia, spastic paraplegia, pseudo-bulbar palsy, and a minimal visual disturbance, with neither adrenal nor hypogonadal symptoms. The morphological and biochemical findings in this case are identical with those in typical adrenoleukodystrophy, but the topographical distribution of the lesions is distinctly different. The changes selectively affect the white matter in the cerebellum and brain stem in contrast to minimal involvement of the occipital white matter.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 60 (1983), S. 309-313 
    ISSN: 1432-0533
    Keywords: Hirano bodies ; Extraocular muscle ; Aging ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thirty-three rectus superior extraocular muscles from 23 autopsy cases, all over 60 years, were examined. Eosinophilic inclusions (Hirano bodies) were observed in all the muscles; they were stained deep red by Masson's trichrome stain and were positive for protein stain. They consisted of a collection of filamentous structures of two types: (1) a regular array of filaments 100 Å in diameter which sometimes were arrayed in perpendicular planes and (2) another type in a herring bone or ladder-like pattern. Both structures were closely associated with the accumulated thin filaments 50–60 Å in diameter (actin?) in the subsarcolemma. The frequent appearance in aged muscle fibers of Hirano bodies indicates that their formation is a change closely related with aging.
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  • 17
    ISSN: 1432-0568
    Keywords: Electron microscopy ; Mesonephric duct ; Fetus ; Glycogen ; Human development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human mesonephric duct epithelial cells contained empty appearing regions in the infranuclear cytoplasm when prepared for transmission electron microscopy using glutaraldehyde and osmium fixation. The same regions stained positively with PAS in Epon sections for light microscopy suggesting that glycogen was present. Incubation with saliva abolished the reaction. For electron microscopy the glycogen stained very intensely if a mixture of osmium tetroxide and potassium ferrocyanide was used instead of osmium alone. Glycogen accumulations were present between the ages of 5 to 10 weeks and absent at the age of 15 weeks. Reports by others indicate that glycogen may be present in different reactive forms in relation to its staining behaviour after various fixatives. The present results, and similar studies in other tissues, indicate that osmium tetroxide-potassium ferrocyanide fixative should be used routinely for preservation of embryos and fetuses and where indicated, for ultrastructural identification of glycogen and cytoplasmic filaments in clinical specimens.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 275 (1983), S. 156-158 
    ISSN: 1432-069X
    Keywords: Sarcoidosis ; Fcγ-receptors ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immune complexes of horseradish peroxidase (HRP) and rabbit IgG antibodies to HRP were used to study the Fcγ-receptors in granulomas of cutaneous sarcoidosis. Cryostat sections of skin biopsies were incubated with HRP-anti-HRP, and the peroxidase activity was demonstrated with 3,3-diaminobenzidine tetrahydrochloride and H2O2. Most cells in the granulomas, both epithelioid and giant cells, were stained. By electron microscopy, the reaction products were localized to the plasma membranes of the cells as well-defined granular deposits. No reaction product was demonstrated intra- or extracellularly.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 275 (1983), S. 407-411 
    ISSN: 1432-069X
    Keywords: Langerhans cell ; ATPase ; Ia-like antigen ; OKT6 ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 60 (1983), S. 271-277 
    ISSN: 1432-0533
    Keywords: Tuberous sclerosis ; Subependymal giant-cell tumor ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tissue from seven patients with tuberous sclerosis and subependymal giant-cell tumors was examined with special stains, immunohistochemistry, and electron microscopy. Immunoreactive glial fibrillary acidic protein (GFAP) was not found in the giant cells of four tumors, but was present in some tumor cells in the other three. Immunoreactive S-100 protein was present in tumor cells of six cases; it was also seen in more tumor cells than was GFAP. Electron microscopy was similar in all cases and showed that the tumor cells had numerous organelles — many dense bodies thought to be primary lysosomes, swollen mitochondria, Golgi complexes, rough and smooth endoplasmic reticulum, free ribosomes, and sparsely distributed intermeadiate filaments. In one case, neurosecretory granules, microvilli, and synapses were observed. In another subject, prominent, thick bundles of glial filaments were seen. These findings suggest that the tumor is made up of unique cells in addition to cells with recognizable neuronal or astrocytic features.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 59 (1983), S. 139-144 
    ISSN: 1432-0533
    Keywords: Decompression sickness ; Brain ; Gas bubbles ; Blood-bubble interface ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rats were exposed to 6.1 bar (abs.) air for 90 min and subsequently decompressed to the ambient pressure. After a decompression rate of 6.8 bar/min pial veins and superior sagittal sinuses were found to contain gas bubbles; no intravascular bubbles were observed subsequent to a decompression rate of 1.5 bar/min. Under the electron microscope platelet aggregates were observed at both the electron-dense layer of the blood-bubble interface and in pial veins with no bubbles. It is concluded that during decompression sickness bubbles and both activation and aggregation of platelets occur in intracranial veins. Subsequent venous congestion may contribute to the neuronal lesions and symptoms of acute decompression sickness.
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  • 22
    ISSN: 1432-069X
    Keywords: Pityriasis rubra pilaris ; Histochemistry ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five patients with pityriasis rubra pilaris (PRP) were analyzed by means of light and electron microscopy as well as by histochemistry and autoradiography. The results were compared with findings in psoriasis vulgaris. In PRP we found a moderate increase of the labeling index of epidermal cells, a highly increased labeling index of dermal infiltrating cells, and a mild spongiosis, and in the stratum granulosum, a decreased number of tonofilaments and an increased number of keratinosomes. The horny layer in PRP showed a pronounced histochemical and electron microscopical parakeratosis, even when histological parakeratosis was absent. In contrast with psoriasis vulgaris, there was no exocytosis of polymorphonuclear leucocytes into the epidermis, the papillomatosis index was normal, and there were no tortuous capillaries in the dermal papillae. The stratum granulosum was always present and sometimes thickened, showing electron microscopical changes different from those referred to in psoriasis. These changes point to a relatively distinct pattern of epidermal changes in PRP.
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  • 23
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    Electronic Resource
    Springer
    Annals of hematology 47 (1983), S. 13-19 
    ISSN: 1432-0584
    Keywords: Acute lymphoblastic leukemia ; Intracytoplasmic inclusions ; Mitochondria ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A patient with acute lymphoblastic leukemia (ALL) with cells containing two types of cytoplasmic inclusions is described. The inclusions appeared as glubular bodies containing electron dense material with homogenous structure and as crystalloid formations confined in organelles with structure similar to that of the surrounding mitochondria. In distinction to other reports, these structures were not related to the endoplasmic reticulum. The possibility that some of them represented altered mitochondria is discussed.
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  • 24
    ISSN: 1432-0738
    Keywords: Cadmium ; Toxicology ; Electron microscopy ; Endothelium ; Liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract With quantitative techniques at electron microscopical level chromatin condensation and emptying of the interchromatin space have been established in the nuclei of the endothelial cells of small uterine vessels. The nuclear and cytoplasmic changes after cadmium administration show much similarity between endothelial cells of small uterine vessels and cultured liver parenchymal cells. Cytoplasmic changes in both cell types after cadmium administration are suggestive of a disturbance in ribosomal RNA synthesis as the main cause leading to ultimate cell lysis.
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  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 53 (1983), S. 151-163 
    ISSN: 1432-0738
    Keywords: Fenofibrate ; Human liver ; Electron microscopy ; Morphometry ; Peroxisomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In rodents fenofibrate shares with other triglyceride-lowering agents the potential to increase the liver peroxisome population. It was therefore of interest to look for this effect in hyperlipoproteinemic patients receiving this drug. Light and electron microscopy of liver biopsies from a group of 10 patients treated with fenofibrate and from another group of 15 receiving diet only, show no morphological difference between both groups. In contrast with the rodent data the morphometric study reveals no significant changes in the number (fenofibrate group: 7.96 1010 cm−3; group receiving diet alone: 8.41 1010 peroxisomes/cm3 of liver tissue) or in the size (fenofibrate group: Diameter=0.53±0.07 μm — group receiving diet alone: 0.50±0.06) of peroxisomes. The difference between our results and those obtained consistently in rodents may be due to the relatively low dose in man and/or a species-dependant difference in enzyme content of liver peroxisomes, itself related to an apparent difference in the way in which lipids are handled.
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  • 26
    ISSN: 1432-0983
    Keywords: Allomyces macrogynus ; Mitochondrial DNA ; Electron microscopy ; Restriction enzyme map
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The mitochondrial (mt) DNA of the aquatic phycomycete Allomyces macrogynus is a circular molecule with a size of 56.1 kbp. The cleavage sites for the restriction enzymes SalI and PvuI were mapped by comparing the partial denaturation patterns of isolated restriction fragments with the pattern of the intact circle. The genes coding for the small and large ribosomal RNA (rRNA) were located on the restriction map by heteroduplex and R-loop analysis. The gene coding for the large rRNA contains an intervening sequence, app. 0.7 kbp in size, near the 3′-end of the gene. The two rRNA genes are encoded on the same strand of the mtDNA and separated by a region of 17–18 kbp. This rRNA gene organization is similar to that found with members of the Ascomycetes.
    Type of Medium: Electronic Resource
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  • 27
    Electronic Resource
    Electronic Resource
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    Journal of molecular medicine 61 (1983), S. 593-599 
    ISSN: 1432-1440
    Keywords: Small intestine ; Early ischemia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphology and chronology of an absolute ischemia was investigated on the small intestine of man and rat. It could be shown that the morphogenesis of ischemic damage to the intestinal mucosa in man does not differ from that in the rat. However, there are crucial and in therapeutic terms significant differences in the time course of the ischemic damage to the intestinal mucosa. Whereas in the small intestine of the rat, the first appreciable alterations — detachment and disruption of the lining epithelium at the villous tip — are already to be observed after absolute ischemia lasting 15 min, in the human small intestine the same lesions only occur after 4 h. A comparable complete necrosis of the small intestinal mucosa was detected in the rat after 7-h ischemia, and in man after 44-h ischemia.
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  • 28
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    Archives of microbiology 135 (1983), S. 169-175 
    ISSN: 1432-072X
    Keywords: Photosynthetic membranes ; Electron microscopy ; Image processing ; Ectothiorhodospira halochloris ; Ectothiorhodospira abdelmalekii ; Rhodopseudomonas viridis ; Rhodopseudomonas sulfoviridis ; Thiocapsa pfennigii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The photosynthetic membranes of the five bchl b-containing bacteria Ectothiorhodospira halochloris, E. abdelmalekii, Rhodopseudomonas viridis, R. sulfoviridis and Thiocapsa pfennigii have been investigated by electron microscopy and digital image analysis. All five species have the photosynthetic complexes hexagonally arrayed in the membrane with lattice spacings close to 13 nm, except for R. sulfoviridis and T. pfennigii which display somewhat smaller (∼12.5 nm) lattice spacings. Correlation averaging which imposes less stringent requirements on the lattice perfection than conventional Fourier filtration techniques has been employed to elucidate the structure of the photosynthetic complexes. Their basic organization, i.e. a ring, probably containing the light-harvesting (LH) polypeptides, surrounding a core (the “reaction centre”) appears to be almost identical for all species under scrutiny. Despite a resolution of ∼1.6 nm, however, little further significant substructure can be deduced from the averages; possible reasons for the “blurred” appearance of the LH-ring and absence of any subdivision in the reaction centre are discussed along with strategies aimed at obtaining a more detailed model of the molecular architecture of the photosynthetic membranes.
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  • 29
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    Archives of microbiology 135 (1983), S. 25-29 
    ISSN: 1432-072X
    Keywords: Electron microscopy ; Euglena mutabilis ; Flagellate ; Photomovement ; Photoreceptor ; Phototaxis ; Single-cell analysis ; Videomicroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Due to the lack of an emergent flagellum the green flagellate Euglena mutabilis is restricted to gliding motility. During forward movement, the organisms orient positive phototactically in the presence of a suitable light stimulus. The cell contains both a stigma and a paraflagellar body which differ in shape and size from the organelles found in E. gracilis. The degree of orientation in white light follows an optimum curve with a maximum at about 100 lx. The spectral sensitivity shows a number of prominent peaks in the blue and green regions and extends well into the red region of the visible spectrum. Since the cell does not rotate during locomotion a periodic shading mechanism cannot account for phototactic orientation. Thus, phototaxis in the related species, E. gracilis and E. mutabilis differ in their photoreceptor molecules, their sensory transduction chains and their strategies of light direction detection.
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  • 30
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    Journal of cancer research and clinical oncology 105 (1983), S. 285-291 
    ISSN: 1432-1335
    Keywords: Borderline lesion ; Severe dysplasia ; Gastric precancerosis ; Electron microscopy ; Morphometric analysis ; Bleb formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The “borderline lesion” of the stomach (severe dysplasia of the protruded type) is nowadays considered to be a true precancerous lesion. Histologically, this lesion is characterized by a proliferation in the area of the glandular neck, combined with severe cellular atypia. Investigation by means of transmission electron microscopy reveals the structure of these cells to be very similar to the structure of cells of an intestinal-cell-type carcinoma of the stomach. In addition to signs for a loss of differentiation of the cells, such as the absence of rough-surfaced endoplasmatic reticulum, mucin granules, and of the polarity of the cells, remarkably frequently luminal bulges and “blebs” developed to various extents can be detected. Morphometric analysis is delineating the tendency of structural features of the borderline lesion to develop toward the gastric cancer cell. These irregularities might be expressions of the beginning of expansive growth and signs pointing to differentiation into malignant neoplasia.
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  • 31
    ISSN: 1432-2307
    Keywords: Cystitis ; Electron microscopy ; Vasculitis ; Elastic tissue ; Autoimmune diseases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bladder vessel walls of 20 patients with interstitial cystitis were studied by the electron microscope. 14 (70%) had severe endothelial injury. 10 (50%) showed injured smooth muscle cells. Odd basement membrane proliferations and disruptions were seen. Clusters of microfibrils about 10 nm in diameter and numerous partially membrane-bound vesicles of 100–600 nm with granular or tiny vesicular content (“granulovesicular bodies”) were also seen. Intercellular junctions of endothelial cells were open and there was emigration of polymorphonuclear leucocytes and platelets. The findings show pronounced vascular injury to have taken place, with neoformation of elastic tissue. It is suggested that the injury is immunologically mediated and that particularly those clusters of connective tissue microfibrils not yet covered by an amorphous elastin component may be involved in the pathogenesis of this disease.
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  • 32
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    Virchows Archiv 401 (1983), S. 109-128 
    ISSN: 1432-2307
    Keywords: Clear-cell sarcoma ; Electron microscopy ; Immunohistochemistry ; Neural crest ; S-100 protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A clinico-pathological, light microscopic and immunohistochemical study of 15 clear-cell sarcomas, with an ultrastructural analysis of 6 of the tumors, is presented. The tumors showed a strong predilection for tendons and aponeuroses of the extremities in predominantly young and middle-aged people. The clinical setting, course and light microscopic appearance agree well with the original description by Enzinger (1965). Nine of the 15 patients developed metastases, most of them including lymph nodes, and 8 of the patients had died at the time of follow-up (median follow-up time 4.8 years). Reducing pigment was demonstrated within the cells of 2 tumors. Ultrastructurally the 6 tumors studied had a uniform appearance with characteristically rounded or oval tumor cells with a single nucleus containing one or two very prominent nucleoli, a light-staining cytoplasm with a moderate amount of organelles and a variable content of glycogen. Polymorphic melanosomes were seen in the cells of one of the tumors. External laminas enclosed groups of tumor cells and invested parts of individual tumor cells. With immunoperoxidase analysis for S-100 protein positive staining was observed in the vast majority of the tumor cells of all 15 clear-cell sarcomas. Metastases appearing in 9 of the 15 cases showed positive staining for S-100 protein. There was a strong staining of the cytoplasm and generally a weak and varying staining of nuclei. The immunohistochemical and electron microscopic findings indicate that clear-cell sarcoma is a homogenous entity among soft tissue sarcomas, of probable neural crest derivation.
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  • 33
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    Cell & tissue research 234 (1983), S. 469-496 
    ISSN: 1432-0878
    Keywords: Bone marrow (human) ; Neutrophil granulocyte ; Granules ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Bone marrow from hematologically healthy adults was exposed to a number of fixation procedures for investigation of the heterogeneity of the granule population in neutrophil granulocytes at the ultrastructural level. Four main cell stages were distinguished: early promyelocyte, late promyelocyte, myelocyte, and mature neutrophil granulocyte and described separately; metamyelocytes and band-form or stab cells are described together. The characteristic changes in the cytoplasm during myelopoiesis were analysed quantitatively. Special attention was given to the development of the granule population. Three types of granule arise in successive cell stages: granules which develop a sub-structure in the matrix (nucleated granules) are formed in early promyelocytes, granules with a homogeneous electron-dense matrix (azurophil granules) in late promyelocytes, and granules with a less electron-dense matrix (specific granules) in myelocytes. The three types of granule remain present during myelopoiesis. The best results in distinguishing the granule types were obtained by prefixation either in 0.1% glutaraldehyde or in 1.5% glutaraldehyde followed by washing in phosphate-buffered Ringer solution to which aminotriazole had been added. Granule counts revealed for the mature neutrophil a total number of granules of about 220 per ultrathin section. This population of granules is composed of about 12% nucleated, 11% azurophil, and 77% specific granules. When our previous findings are taken into account, the existence of three successively formed and morphologically distinguishable types of granule in heterophil (neutrophil) granulocytes has been demonstrated for three mammalian species: the guinea pig, the rat, and man. A separate term for the early promyelocyte stage is proposed: eomyelocyte.
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  • 34
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    Cell & tissue research 234 (1983), S. 579-593 
    ISSN: 1432-0878
    Keywords: Rods ; Cones ; Retina ; Bullfrog ; Synapse ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Lumps of electron-dense material were observed in synaptic clefts associated with all types of photoreceptors, in the vicinity of the synaptic ribbons, in the retinae of dark-adapted frogs. Frogs were reared under a cyclic illumination (light on at 8:00; light off at 20:00) and then exposed to one of two courses of dark adaptation: one started from 11:00 in the morning, and the other started from 20:00 in the evening. The synaptic clefts of red rods became wider at some places where spherical or polygonal lumps of dense material were accumulated. The frequency and sectional area of the lumps increased faster for the first hour in the regime starting from 20:00 than in the regime starting from 11:00, then they reached the similar saturation levels of about 0.6 (per ribbon) and 1.6 to 1.8×104 (nm2) in both the regimes. In greenrod synapses, plate-shaped lumps of dense material were present in synaptic clefts and interspaces between the processes of second-order neurons. In cone synapses at the end of about 1 h darkness, the frequency and area of the lumps reached maximum values of about 0.12 (per ribbon) and 9×103 (nm2) in the regime starting from 11:00 and, about 0.08 (per ribbon) and 4 × 103 (nm2) in the regime starting from 20:00. On exposure to light, the dense material abruptly disappeared from all types of photoreceptor synaptic clefts. Large dense-core vesicles, occasionally observed in light-adapted rod photoreceptor terminals, seem to participate in exocytosis of the dense material. The number of dense-core vesicles per synaptic ribbon in a terminal was about 0.55 at the end of 3 h light in the morning and about 1.28 at the end of 12 h light in the evening. The increased number of dense-core vesicles during the daytime may contribute to the faster accumulation of dense material in the synaptic clefts. Although the chemical identification or the functional significance of the electron-dense material remains unknown, it is interesting that this material showed a rise and fall in response to darkness and illumination. Also the fact that this material is clearly visible will be helpful for future analysis of frog photoreceptor synapses.
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  • 35
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    Cell & tissue research 232 (1983), S. 593-600 
    ISSN: 1432-0878
    Keywords: Peritrophic membrane ; Insect ; Microvilli ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A double plasma membrane (DPM) surrounding intestinal microvilli of the migratory milkweed bug, Oncopeltus fasciatus, is described. Mutant and wild types of the phytophagous insect have been studied by conventional SEM and TEM procedures with the use of membrane-enhancing staining methods. Longitudinal and transverse sections revealed a DPM surrounding microvilli and continuing over the apical portions of the intestinal cell. The outer membrane of the DPM contributes to an intestinal lining or peritrophic membrane (PTM), which apparently accumulates in layers. SEM studies reveal a rugose intestinal surface and complete PTM in both starved and fed insects. Only rarely are exposed microvilli seen by SEM. SEM examinations also enable the observation of numerous blebs on the luminal side of the PTM apparently held in position by a neck-like attachment and apparently derived from the outer membrane of the DPM. Preliminary TEM studies of microvilli revealed unique microvesicle-like structures, lying just inside the inner membrane of the DPM, which may be of membrane origin based on their typical trilaminar appearance after en bloc staining with uranyl acetate. Highly ordered microfilaments were observed to occupy the most central aspect of the microvilli.
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  • 36
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    Cell & tissue research 234 (1983), S. 125-134 
    ISSN: 1432-0878
    Keywords: Vasopressin ; Immunocytochemistry ; Electron microscopy ; Hypothalamus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vasopressin-containing neurons, identified by immunocytochemistry, are located predominantly in the posterior magnocellular division of the paraventricular nucleus of the rat hypothalamus. By electron microscopy, the immunoreaction product is seen within the cell bodies and neuronal processes. In the perikarya and dendritic processes, the immunoreactive material is associated primarily with neurosecretory granules. Axonal processes, identified by their content of microtubules and accumulation of neurosecretory granules, show the immunoreaction product in association with both of these organelles. Afferent axo-dendritic, axo-somatic and putative axo-axonic synapses with immunostained vasopressinergic neurons can be identified. The presynaptic profiles do not contain immunoreactive material. This study contributes to the ultrastructural characterization of vasopressinergic neurons in the paraventricular nucleus and of their afferent synaptic input.
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  • 37
    ISSN: 1432-0878
    Keywords: Dictyosome-like structures ; Golgi apparatus ; Phosphatidylcholine ; Laminated figures ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Dictyosome-like structures (DLS) of guinea pig spermatocytes, when prefixed in mixtures of glutaraldehyde and tannic acid, exhibited laminated figures with a repeating periodicity of about 4.5 nm in the spaces between DLS saccules or in association with the surfaces of the DLS saccules. These laminated figures were similar to those figures derived from saturated lipids in other tissues. Alternatively, spaces between saccules were collapsed leaving only thin, electron-dense material separating adjacent saccules. These changes were not observed when the DLS were prefixed in glutaraldehyde before exposure to tannic acid. The presence of laminated figures following fixation with tannic acid and osmium tetroxide suggests that saturated lipids are present in, or associated with, the intersaccular regions of the DLS. The distribution of laminated figures in other membrane structures was not affected by post fixation with tannic acid nor were laminated figures comparable to those of the DLS observed between cisternae of the Golgi apparatus. These results support previous conclusions that DLS are distinct from Golgi apparatus and are a unique component of the germ cell cytoplasm.
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  • 38
    ISSN: 1615-6102
    Keywords: Digestion ; Membrane flow ; Electron microscopy ; Sarcodina ; Actinophrys sol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The digestion of food in the heliozoonActinophrys sol is characterized by several distinct membrane events. Initially, extrusomes expand and fuse with each other and with the plasma membrane providing the membrane for the nascent food vacuole. During this process a—presumably lytic—material is secreted. After complete forming of the food vacuole a second type of vesicles fuses with it, whereupon usually lysis of the prey occurs. After denaturation and coagulation of the food, fluid is removed from the food vacuole. This process is accompanied by a high cytotic activity around the periphery of the food vacuole. Following this step, the perinuclear Golgi region shows an active appearance and numerous lysosomes fuse with the food vacuole. In consequence of this the food is degradated. The food vacuole shrinks continuously. Simultaneously vesicles filled with the digested material pinch off from the food vacuole, the content of which shows a more and more condensed mass of undigestible material. The undigestible residues are defecated eventually. The process of digestion is accompanied by an increase in volume and number of electron lucent cytoplasmic vacuoles. These vacuoles gradually become filled with a filamentous material starting with the vacuoles in the cell periphery. As the digestion continues, the vacuolar contents become condensed successively. Synchroneously the vacuoles move towards the cell center. After completion of the digestion, the cytoplasmic vacuoles decrease in volume and number and do not show any longer electron dense contents.
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  • 39
    ISSN: 1615-6102
    Keywords: Anacystis nidulans ; Cyanobacterium ; Electron microscopy ; Freeze-fracmres ; Thylakoid degradation ; Ultrathin-sections
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Photooxidative bleaching of the CyanobacteriumAnacystis nidulans was studied by electron microscopic investigation of both freezefractured and thin-sectioned samples. During bleaching four consecutive phases in degradation of photosynthetic membranes (thylakoids) could be characterized: 1. No ultrastructural changes until photosystem II activity is lost. 2. Derangement of characteristic arrangement of thylakoids. 3. Thylakoids visible only in thin-sectioned but not in freeze-fractured samples. 4. Completely bleached cells, only traces in place of former thylakoids visible in thinsectioned samples. Bleaching did not cause lysis of the cells showing that the cytoplasmic membrane was not damaged. Polyhedral bodies also were still detectable in bleached cells.
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  • 40
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    Protoplasma 116 (1983), S. 198-200 
    ISSN: 1615-6102
    Keywords: Chromosome isolation ; Electron microscopy ; Vicia faba ; Vicia narbonensis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using a formalin fixation technique whole chromosomes from root tips ofVicia species were isolated into a buffer solution. Combining this technique with the use of a set of reciprocal translocations available for this species—Vicia faba— allowed each member of the karyotype to be isolated and identified. Such isolated chromosomes can be used for optical microscopy or for either transmission or scanning electron microscopy where critical point drying clearly reveals chromatin fibre.
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  • 41
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    Protoplasma 116 (1983), S. 209-212 
    ISSN: 1615-6102
    Keywords: Parapharyngeal mass ; Electron microscopy ; Cytochemistry ; Electron microprobe X-ray analysis ; Ciliate ; Homalozoon vermiculare
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The structure and elemental composition of the granules which make up the parapharyngeal mass of the ciliateHomalozoon vermiculare are analyzed. The mass is made up of two kinds of granules. One is not membrane-bounded and is composed of paraglycogen. The second type is comprised of concentric lamellae. It is rich in magnesium, phosphorus, potassium, and calcium. These results do not support the contention that the granules are directly involved in the process of food vacuole formation. The role of the parapharyngeal mass remains obscure.
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  • 42
    ISSN: 1615-6102
    Keywords: Cell walls ; Electron microscopy ; Moisture ; Plastic embedding ; Seeds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Aqueous fixatives caused dry seed tissues to swell; mashed peanuts, crushed to remove oil, swelled even more. Use of anhydrous, organic solvents as vehicles for fixatives enabled maintenance of dimensional stability during fixation of dry seed tissues; even crushed seed tissue did not swell significantly when processed anhydrously. However, anhydrously processed specimens proved difficult to section. The difficulty was due to imperfect permeation of plastic into the seed tissues during embedding. An explanation of why anhydrously processed dry seed tissues are so difficult to embed in plastic is offered.
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  • 43
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    Cell & tissue research 228 (1983), S. 139-148 
    ISSN: 1432-0878
    Keywords: Pineal organ ; Pineal photoreceptors ; Opsin immunoreactivity ; Electron microscopy ; Elasmobranch (Raja clavata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal organ of Raja clavata was studied by light and electron microscopy, including the immunocytochemical antiopsin reaction. The pineal organ of the ray consists of three portions: (i) a large proximal pineal, (ii) a long tube-like connecting stalk, and (iii) a short distal terminal enlargement. This latter end-vesicle lies in the deep connective tissue layers of the braincase. All portions of the pineal are composed of pinealocytes, intrinsic neurons, ependymal/glial cells, and bundles of nerve fibers embedded in thin neuropil formations. The inner segments of the pinealocytes protrude into the lumen in all parts of the organ and usually contain basal bodies and numerous mitochondria. Often, two outer segments were found to arise from the basal bodies of a single inner segment. By means of light-microscopic immunocytochemistry the outer segments showed a strong antiopsin reaction. The axons of the pinealocytes form ribbon-containing synapses on dendritelike profiles, which appear to belong to the intrinsic pineal neurons. There are other axo-dendritic synapses established by presynaptic terminals lacking ribbons and containing granular and synaptic vesicles. Pineal neurons may contain granular vesicles approximately 60–100 nm in diameter; their processes contribute to the bundles of unmyelinated axons. The fine structural organization of the pineal organ and the opsin immunoreactivity of the outer segments of the pinealocytes indicate a photoreceptive capacity of the organ. The double outer segments represent a peculiar multiplication of the photoreceptor structures.
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  • 44
    ISSN: 1432-0878
    Keywords: Innervation ; Decentralisation ; Hypogastric nerve ; Pharmacology ; Electron microscopy ; Vas deferens ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The physiological, pharmacological and morphological characteristics of guinea-pig vas deferens supplied by hypogastric nerves rendered inactive by decentralisation were compared with those of vas deferens in which the nerve supply had been chronically stimulated for 3–9 days using implanted electrodes. No change was seen in decentralised preparations prior to 7 days, but from 8–15 days, increased sensitivity to application of noradrenaline in vitro was observed, which was shown to be related to reduced transmitter uptake by nerve terminals as well as to an increase in postjunctional sensitivity; there was also increased fatigability 7–14 days following decentralisation. Continuous stimulation of hypogastric nerves at 2 Hz for 4–8 h daily for 4–8 days resulted in enhanced transmitter uptake and reduced responses to noradrenaline; this was associated with a slight increase in noradrenaline content and a faster adrenergic neuromuscular response with a shorter latency. No appreciable changes in nerve or muscle structure studied by electron microscopy were observed following decentralisation, but there was an increase of between 12.5 and 29.6% in the number of close (〈 100 nm) neuromuscular junctions following chronic stimulation for 8 days.
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  • 45
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    Cell & tissue research 228 (1983), S. 433-449 
    ISSN: 1432-0878
    Keywords: Bone marrow (rat) ; Heterophil granulocyte ; Granules ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The development of the heterophil granulocyte in the bone marrow of the rat is described, and an electron-microscopical analysis of the changes in the cytoplasm as well as in the granule population in several stages of maturation is reported. Three types of granule originate in consecutive stages of heterophil maturation. Granules with an internal fine structure (nucleated granules) are the first to be formed, i.e., in early promyelocytes; azurophil granules are formed in late promyelocytes; and specific granules appear in myelocytes. Quantitative analysis showed that the granule population in mature cells, i.e., about 160 granules per electron micrograph, is composed of roughly 14% nucleated granules, 10% azurophil granules, and 76% specific granules. Three cell stages were observed in mitosis: the early promyelocyte, the late promyelocyte, and the myelocyte. Granule counts in non-dividing cells confirmed the occurrence of mitosis in the late promyelocyte and myelocyte.
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  • 46
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    Cell & tissue research 228 (1983), S. 489-496 
    ISSN: 1432-0878
    Keywords: Heart ; Tissue culture ; Electron microscopy ; Myocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cardiac muscle cells from 3-day-old rat neonates were cultured for periods of 2 to 56 days. In order to facilitate ultrastructural studies on the organization of the sarcoplasmic reticulum, the cells were prepared for transmission electron microscopy according to a regimen including postfixation in reduced osmium ferrocyanide. The nonjunctional sarcoplasmic reticulum (NJSR) was organized as a loose, fenestrated sleeve around the exterior of bundles of myofilaments and was particularly prominent at the level of the Z line. The only recognizable junctional elements of the sarcoplasmic reticulum were in a peripheral location. Reduced osmium ferrocyanide was also useful in distinguishing intermediate (10nm) filaments, since it understained Z substance, which often obscured these structures. Intermediate filaments were arranged both at the Z line and the intercalated disc, in parallel strands, approximately at right angles to the myofilaments.
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  • 47
    ISSN: 1432-0878
    Keywords: CRF ; immunolabelling ; Paraventricular nucleus ; Median eminence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The corticotropin releasing factor (CRF)-synthesizing perikarya and neural processes were detected at ultrastructural level in the hypothalamic paraventricular nucleus and in the median eminence of control and colchicine-pretreated rats. The unlabelled antibody peroxidase-antiperoxidase complex (PAP) immunohistochemical method was used in a pre-embedding manner, on thick, non-frozen sections. In CRF-perikarya, neurosecretory granules (80–120 nm in diameter), free ribosomes, and the rough endoplasmic reticulum were labelled. Unlabelled axon terminals formed asymmetric synapses on CRF-containing perikarya and dendrites. Immunolabelled axons terminated in the palisadic zone of the median eminence.
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  • 48
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    Cell & tissue research 232 (1983), S. 379-397 
    ISSN: 1432-0878
    Keywords: Electron microscopy ; Pelvic ganglia ; Autonomic nervous system ; Synapses ; Neurones ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A semi-quantitative electron-microscopic study of neuronal cell bodies, nerve profiles and synapses in the anterior pelvic ganglia of the guinea-pig has been carried out following in vivo labelling of adrenergic nerve endings with 5-hydroxydopamine. Ganglion cells of three main types have been distinguished: 1) the majority (about 70%) not containing granular vesicles, probably cholinergic elements; 2) those containing large granular vesicles of uniform size (80–110 nm), with granules of medium density and prominent halos; and 3) those containing vesicles of variable size (60–150 nm), with very dense eccentrically placed granular cores. Some non-neuronal ‘granule-containing’ cells were present, mainly near small blood vessels. Some 95% of the total axon profiles within the ganglia were cholinergic, the remaining 5% were adrenergic. However, 99% of synapses (i.e. axons within 50 nm of nerve cell membrane with pre-and post-synaptic specialisations) were cholinergic, and 1 % were adrenergic. Only three examples of nerve cell bodies exhibiting both cholinergic and adrenergic synapses were observed. Unlike the para-and prevertebral ganglia, the pelvic ganglia contained large numbers of axo-somatic synapses. As many as 20% of the nucleated neuronal cell profiles displayed two distinct nuclei.
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  • 49
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    Cell & tissue research 232 (1983), S. 399-411 
    ISSN: 1432-0878
    Keywords: Pelvic ganglion ; Reinnervation ; Decentralisation ; Autonomie nervous system ; Electron microscopy ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron-microscopic study has been made of adrenergic and cholinergic nerve fibres and synapses in the pelvic ganglion of the guinea-pig at intervals of up to 60 days following section of the hypogastric and pelvic nerves. Transection of the hypogastric nerves led to degeneration of 80–90% of the cholinergic nerve profiles and synapses in the ganglion. The small number of adrenergic nerves and synapses did not change, but 30–60 days after section, this number increased 8–10 times. Transection of the pelvic nerves led to degeneration of about 15% of the cholinergic nerve terminals, but no change in adrenergic terminals. After transection of both hypogastric and pelvic nerves, only about 1% of cholinergic nerves survived, but after 30–60 days, the number of adrenergic nerves increased 8–10 times. It is concluded that following cholinergic nerve degeneration in the ganglion, adrenergic nerves, probably originating as collateral sprouts from postganglionic neurones and granule-containing cells, can replace them to some extent.
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  • 50
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    Cell & tissue research 228 (1983), S. 85-98 
    ISSN: 1432-0878
    Keywords: Basement-membrane production ; Mouse embryos ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mouse embryos (strain NMRI) of days 9 + 2h, 9 + 12h, 10 + 2h, 10 + 12h, 11 + 2h, 12 + 2h, 13 + 2h, and 14 + 2h were fixed (i) in 3% glutaraldehyde +3% paraformaldehyde, (ii) in 1% glutaraldehyde +1% tannic acid, or (iii) in 1% glutaraldehyde +1.5% ruthenium red. The electronmicroscopic picture of the basement membrane (BM) changed depending on the fixative used. Addition of tannic acid led to a higher staining intensity of glycoproteins, whereas after ruthenium red proteoglycans were more heavily stained. The BM around the neural tube and around the epithelial tubules in the lung anlage were investigated electron microscopically. After fusion, the BM in the dorsal regions of the neural tube is missing; on days 9–10 it is, however, reformed. Between days 11 and 13 wide gaps in the BM of the lung anlage occur at the growth buds of the epithelial tubes, which are bridged on late day 13. In the basal parts of these two epithelial types membrane-bordered granules of different density occur singly or in groups. It is postulated that these structures contain BM-material and represent secretion granules. After secretion, BM-material is first bound to the cell membrane. This process is important for the initiation of the formation of the BM. Further growth, however, proceeds via lateral aggregation (self-assembly). Thus, intercellular gaps are bridged independent of the cell membrane. The process of lateral aggregation may also explain deviations from the normal course of the BM.
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  • 51
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    Cell & tissue research 230 (1983), S. 639-648 
    ISSN: 1432-0878
    Keywords: Non-adrenergic, non-cholinergic autonomic nerves ; Quinacrine ; Fluorescence microscopy ; Electron microscopy ; Anococcygeus muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological changes induced in the autonomic nerves of the rat anococcygeus muscle after the injection of quinacrine (QC, 100 or 200 mg/kg) were examined by electron microscopy in order to clarify the nature of QC-binding nerves seen at the fluorescence-microscopic level. A correspondence between granular QC fluorescence and many lysosomal dense bodies is observed both in the cytoplasm of muscle cells and in non-adrenergic, non-cholinergic (NANC) axons during the first few days following injection. A number of brilliantly fluorescent fibres is observed 1 week after injection. At the ultrastructural level, these fibres seem to correlate with NANC axons which are crowded with many dense bodies and large granular vesicles. Notably, some lysosomal dense bodies contain many large granular vesicles. The effects of QC injection on the ultrastructure of adrenergic axons have also been observed, but are not so marked as in the NANC axons. The administration of QC did not cause complete degeneration of the NANC nerves, though degenerating axons were sometimes observed. The present data indicate that most, if not all, QC-binding nerves observed at the fluorescence-microscopic level correspond to NANC nerves at the electron-microscopic level. Furthermore, NANC axons appear to contain a considerable amount of ATP concentrated in the large granular vesicles.
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  • 52
    ISSN: 1432-0878
    Keywords: Bone marrow (mouse) ; Monocytes ; Neutrophil granulocytes ; Granules ; Electron microscopy ; Peroxidase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The differentiation and maturation of monocytes and neutrophil granulocytes were studied in bone marrow of normal mice by electron microscopy and cytochemical assessment of peroxidatic activity. The granule populations of the mature cells of bone marrow were identified and investigated to obtain a basis for the analysis of the earlier stages of maturation. Mature monocytes and neutrophils showed primary and secondary granules, and mature neutrophils had more of both kinds. The size, shape, and number of primary granules proved to offer the most reliable criteria for distinguishing promonocytes and promyelocytes. The primary granules of monocytes were smaller than those of mature neutrophils and were either spherical (smallest diameter 50–200 nm) or elongate (100×400 nm). Both granules had a homogeneous matrix. The granules of the granulocytes were either spherical (smallest diameter 200–300 nm) or elongate (150–200×300–500 nm), and some of them had a crystalline inclusion.
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  • 53
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Anura ; Stomach ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The young of the aquatic Australian frog, Rheobatrachus silus (Leptodactylidae) develop from eggs to juvenile frogs in the mother's stomach. During brooding the stomach expands greatly and becomes very thin walled. Transmission electron microscopy showed that the distension of the stomach was accompanied by a severe disruption of the smooth muscle layers. Many of the smooth muscle cells seemed to be highly contracted and resembled smooth muscle cells contracted in the absence of an intact connective tissue matrix. Eight days after the birth of the juveniles through the mouth of the female, the stomach muscle cells had returned to a normal appearance. It is suggested that during gastric incubation of the young, smooth muscle cells become at least partially dissociated from their surrounding connective tissue matrix, allowing maximal distension of the stomach wall.
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  • 54
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    Cell & tissue research 231 (1983), S. 551-563 
    ISSN: 1432-0878
    Keywords: Visual mutants ; Anterior optic tract ; Independent gene actions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron microscopy shows that in wild-type Drosophila melanogaster the anterior optic tract (AOT) is formed by about 1260 fibers in males and slightly fewer in females. Golgi staining suggests that most AOT fibers connect the lobula with different regions of the central brain. In the sine oculis (so) and small optic lobes (sol) mutants the number of axons is drastically reduced, by 58% in sol and by 35% in so. In the double mutant sol:so there is a loss of up to 83% of the fibers in the AOT. Approximately half of the remaining 220 fibers form a well defined subbundle of very thin axons which is identifiable in wild type as well as in both single mutants. The fibers of this subbundle neither originate nor terminate in the visual ganglia: instead, they connect two different central brain regions. It is concluded that the combined action of the sol and so mutations abolishes more than 90% of the fibers of visual origin or destination in the AOT. Quantitative analysis of electron micrographs shows that the so and sol mutations act independently on nearly exclusive subsets of axons in the AOT.
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  • 55
    ISSN: 1432-0878
    Keywords: Satellite cells ; Skeletal muscle ; Snake-venom toxin ; Muscle regeneration ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Satellite cells were studied in the undamaged part of the rat soleus muscle rendered partially necrotic by a subcutaneous injection of notexin, the myotoxic toxin purified from the venom of the Australian snake Notechis scutatus scutatus. Nuclei of satellite cells were twice as numerous as in the controls, with a decreasing gradient in the number of satellite cells with distance from the necrotic area. The cells were in an activated state with an increased cytoplasmic volume and prominent organelles. Occasionally, mitosis of some satellite cells was observed. Between the satellite cell and the muscle fibre, an unusually wide space was frequently seen, within which a “new” basal lamina was often visible. It is suggested that the role of the satellite cells of undamaged muscle fibres in the regeneration of necrotic muscle is worthy of more detailed investigation.
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  • 56
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    Cell & tissue research 233 (1983), S. 209-213 
    ISSN: 1432-0878
    Keywords: Hamsters ; Harderian glands ; Short photoperiod ; Sexual dimorphism ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A sexual dimorphism of the hamster Harderian gland at the ultrastructural level, has been reported. Castration of males and the administration of testosterone to females are known to alter the male type gland to the female type and vice versa. In this paper we present data that exposure to a short photoperiod (1L:23D) can induce similar structural alterations between the 4th and 10th week of exposure. Changes in the male included reduction in the number of tubular clusters and large vacuoles, while in the female the number of membrane formations decreased with an accompanying appearance of tubular clusters.
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  • 57
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1-15 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The thermal decomposition of this resin was examined by quantitative pyrolysis - gas chromatography. The decomposition does not follow the Hurd-Blunck mechanism generally obeyed by beta-hydrogen containing esters. Instead, phthalic anhydride is extruded almost quantitatively. It is proposed that the mechanism involves the rearrangement of the phthalate C—O bonds to extrude the anhydride, leaving a maleic acid - dipropylene glycol polyester chain.
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  • 58
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 31-39 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-grafted poly(p-phenylene terephthalamide)s (PPTA) were synthesized from PPTA and acrylonitrile or propylene oxide via metalation in a solution of the polymer in a sodium methylsulfinylcarbanion-dimethyl sulfoxide solvent at low temperatures. The introduction of these branches into the amide groups of PPTA increased solubility but decreased thermal stability. The effects of the branches on thermal properties and solubility are discussed. The structure of the graft copolymers is described on the basis of wide-angle x-ray diffraction, infrared spectra, and solubility.
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  • 59
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 73-81 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polymerization of acrylonitrile initiated by a potassium superoxide (KO2)-nitrobenzene system was carried out in anhydrous dimethylsulfoxide (DMSO) at 25°C. The initial rate of polymerization was rapid and a high-molecular-weight polymer was obtained. The molecular weight was proportional to monomer concentration and inversely to concentration of initiator within 5 min. The overall activation energy was estimated as -2.6kcal/mol deg in the temperature range of 20-50°C. In addition to nitrobenzene anion radical, other anion radicals generated by one-electron transfer from KO2 to charge transfer agents such as m-dinitrobenzene benzoquinone, benzophenone, and naphthalene were effective in the polymerization of acrylonitrile. It is proposed that polymerization proceeds via an anionic mechanism that involves one-electron transfer from anion radicals to monomer.
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  • 60
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 97-109 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diaryliodonium salts (I) undergo efficient thermal decomposition in the presence of copper (II) compounds. Such systems can be employed as a novel class of latent thermal initiators for cationic polymerization. An investigation of the mechanism of the reaction demonstrated that the copper (II) compound is first reduced to the corresponding copper (I) compound, which subsequently reduces the diaryliodonium salt. The cationic polymerization of some typical monomers using these new initiators was carried out to demonstrate the scope of their utility.
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  • 61
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 147-154 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It has been found that when hydrophobic monomers are polymerized in the presence of highly hydrophilic polymer seed particles, the second-stage hydrophobic polymers form cores surrounded by the first-stage hydrophilic polymers, resulting in “inverted” core-shell latexes. The formation of core-shell morphology by this inversion process has been found to be dependent on the hydrophilicity and molecular weight of the first-stage hydrophilic polymers and the extent of phase separation between the two polymers involved. Particle morphology has been examined by electron microscopy, surface acid titration, alkali swelling of particles, and surface reactivity.
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  • 62
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 155-163 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structure of polymeric microemulsions, viz. toluene/water/PS-PEO graft copolymer/2-propanol, has been studied by 1H-NMR spectroscopy. Results show that at low water contents, the copolymer adopts a rather diffuse micellar structure in which the rotational mobility of the ethylene oxide units is little affected by the ternary solvent mixture. Above a critical water concentration (ca. 4%), a restriction in mobility of the ethylene oxide chains is observed which has been related to the formation of an inverse micellar structure with water solubilized within the particles. The study of the chemical shifts and linewidths of water protons indicates that initially most of the water is hydrogen bonded to the hydrophilic part of the copolymer, then is present in its free form in water aggregates. These results confirm previous data obtained by dialysis equilibrium experiments.
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  • 63
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 751-760 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The concept of piezoelectric and pyroelectric effects in amorphous polymers is presented, with experimental results, details on sample preparation, and activity evaluation. Most evaluations were performed on 25-30 mol% tributyltin methacrylate/methyl methacrylate copolymers, which possessed good piezoelectric activity, antifouling properties, and paint-formulation characteristics. Solvent-induced orientation effects that lead to piezoelectric activity in amorphous, unpoled, polymers are also described.
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  • 64
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 737-750 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The physical state of the material obtained during the various stages of preparation of a typical MgCl2-supported, high-mileage propylene polymerization catalyst was studied by BET, mercury porosimetry, and x-ray diffraction techniques. The starting MgCl2 and the substance after HCl treatment have negligible BET surface areas. Mercury porosimetry showed that they have large pores with radii 〉 200 nm which are probably crevices between MgCl2 crystallites. The most pronounced physical changes occur during dry porcelain ball milling in the presence of ethyl benzoate. After 60 h or more of ball milling the material had a 5.1-7.3 m2 g-1 BET surface area, twice the pore surface area, and a smaller pore radius than before ball milling and a large reduction in crystallite sizes to almost ultimate dimensions. The crystallites were probably held together by complexation with ethyl benzoate in the form of large agglomerates. Subsequent reactions with p-cresol and triethyl aluminum had minor effects in further reduction of the MgCl2 crystallite size but efficiently brokeup the agglomerates. The final refluxing with TiCl4 increased the BET surface area to 110-150 m2 g-1 but may have increased the crystallite size somewhat due to cocrystallization of TiCl3 and AlCl3 with MgCl2. There may have been only 8-10 crystallites in each catalyst particle. The surface structure of the catalyst resembled those of the classical Ziegler-Natta γ-TiCl3·0.33 AlCl3 catalyst.
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  • 65
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 111-120 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of 4-aminophthalonitrile (APN) with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BPTDA), and with 1,2,3,4-benzenetetracarboxylic dianhydride (PMDA) have been studied to optimize the conditions for the synthesis of monomeric thermosetting bisphthalonitrile compound. Suitable procedures for the synthesis of the two monomers are presented. Elemental analyses, IR spectra, dynamic thermogravimetric analyses, differential scanning calorimetry, 1H-NMR, and mass spectral studies have been used to characterize these compounds. Preliminary observations show that these materials can be polymerized to give high-temperature-resistant materials.
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  • 66
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 141-145 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article is a report of the investigation of the influence of monomer composition within optimum limits on the light-transmitting properties of MBS terpolymers obtained by the mass-suspension method. The high and nearly constant light-transmitting properties of the MS copolymer matrix have no effect on the light-transmitting properties of MBS with a MMA content up to about 20 mol % higher than that at the azeotropic point. The refractive index of the MS copolymers decreases uniformly as the mole ratio of MMA increases and becomes equal to the index of the SBR. Particle concentration in sizes up to 0.6μm increases as the MMA content increases to a given point at which the concentration remains constant as MMA continues to increase. The light-transmitting properties of MBS with a MMA content of 57 mol % are improved significantly. This fact is explained by a decrease in variation on the refractive index between the two phases to 0.0014 and by the increasing percentage of particles with sizes smaller than 0.6 μm up to 70%.
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  • 67
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 175-181 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It was found that aromatic aldehydes and ketones could be reduced smoothly at room temperature by sodium dithionite using viologen derivatives as an electron transfer catalyst to obtain the corresponding alcohols in good yields. Viologens (methyl viologen and polymer) acted catalytically and active species in the reduction were quinoid forms which were obtained by two-electron reduction of viologens.
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  • 68
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 953-960 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For a fundamental study of the electrochemical behavior of electroactive polymers a series of poly(3-vinyl-10-methylphenothiazine) (polyMPT), copolymers of 3-vinyl-10-methylphenothiazine and methyl methacrylate (MMA) (copolyMPT), and 3-ethyl-10-methylphenothiazine (EMPT) (a related monomer model) were prepared. The methylphenothiazine groups in these compounds showed reversible, one-electron oxidation waves in the triangular-were voltammograms. From a detailed comparison of the voltammograms between these polymers and EMPT it was revealed that the electroactive groups in poly MPT were not the “noninteracting” centers in the strict sense, whereas those in copolyMPT, in which the centers are spaced with the MMA segments, were typically noninteracting in nature; that is, in polyMPT the oxidation takes place at the potential 40 m V lower than that of EMPT and copolyMPT exhibited a wave identical to that of EMPT in shape and potential. The exhaustive electron transfer occurred from polyMPT to the electrode. On the other hand, a significant number of centers remained unoxidized in copolyMPT. The self-exchange electron transfer within the polymer coil facilitates the exhaustive oxidation. For this event the proximity of the centers was an essential factor.
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  • 69
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 969-983 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substantial hole transport can be achieved in organic polymers simply by incorporating aromatic amine groups into the monomer. Hole mobilities similar to or greater than those in poly(N-vinyl-carbazole) (PVK) were measured in a series of high molecular weight arylamine-substituted polymethacrylates. The hole transport in these polymers is electric-field-dependent as in PVK, varying between E and E2 within a range of 4 × 104 - ∼9 × 105 V/cm. The polymers also exhibit carrier generation in ultraviolet (UV) light in the range of absorption. Synthesis of the monomers, their polymerization, and the general properties of these polymers are discussed.
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  • 70
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1025-1032 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thermally stable poly(metal phthalocyanine)imide copolymers were prepared with metal(11) 4,4′,4″,4‴ -phthalocyanine tetraamines, 4,4′ -diamino diphenyl ether, and 3,3′,4,4′ -benzophenone tetracarboxylic dianhydride. Variables such as molar concentrations of the reagents, solvents, and temperature were investigated to optimize the conditions of the polymerization. Inherent viscosity, and infrared (IR) spectral and thermogravimetric analysis (TGA) studies were done to characterize the polymers. These polymers are stable and thier decomposition temperatures both in air and nitrogen are greater than 500°C. Their char yields at 800°C in nitrogen varied between 60 and 76%, depending on the type and concentrations of the metal phthalocyanine tetraamines. These polymers can be used to produce heat-stable films, fibers, varnishes, and adhesives.
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  • 71
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 923-936 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The influence of the reaction conditions (time, temperature, concentrations of the monomer, and the initiator) on the amount and composition of the oligomers and high molecular products formed during the heterogeneous anionic polymerization of ∊-caprolactone was investigated. The polymerization was initiated by KC24 in xylene or tetrahydrofuran. Conditions were found under which intra- and intermolecular transesterification was strongly suppressed, thus providing the opportunity for the formation of polyesters with viscometric molecular masses of more than 300,000 and good yields (80% and higher). The total quantity of products with a viscometric molecular mass below 2500 did not exceed 15%; that of the cyclic dimer was not in excess of 5%. Peculiar features of the KC24 initiated polymerization are the insignificant rise in the number of oligomers and the formation of high polymers even in strongly diluted solutions of ∊-caprolactone (0.2 mol/L and lower). The quantity and molecular mass of the polymers obtained decreased as the temperature increased. It was also established that the polymerization of the cyclic dimer of ∊-caprolactone is not initiated by KC24.
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  • 72
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1151-1157 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyaromatic either-sulfone-ketones containing fluoro-substituted p-cyclophane units were prepared from isophthaloyl chloride, terephthaloyl chloride, diphenyl ether, diphenoxydiphenyl sulfone, and a small amount of 1,1,2,2,9,9,10,10-octafluoro-[2,2]-p-cyclophane (type A) or pseudo-p-1,12,2,9,9,10,10-octafluoro-[2,2]-p-cyclophane bis-acid chloride (type B) by Friedel-Crafts-type polymerization. The p-cyclophane units were incorporated as crosslinking sites. Crosslinking was achieved by curing polymers at 300-350°C for several days. The polymers obtained, containing 1-10 wt % fluoro-substituted p-cyclophane units, were moderately soluble in dichloromethane, DMF, and sulfuric acid with inherent viscosities between 0.4 and 0.6. Laminates on glass fiber were made with excellent thermal stability.
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  • 73
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1289-1303 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The esterification of the carboxyl group in copoly(γ-benzyl-L-glutamyl-L-glutamic acid) was carried out using N-hydroxysuccinimide and dicyclohexylcarbodimide to yield the activated site for the coupling reaction with amino compounds. The α-helix stability of the reactive copolymer thus obtained is remarkably affected in the presence of succinimide ring. This copolymer was proved to react nearly completely with amino alcohols such as 2-aminoethanol, 3-aminopropanol, and diethanolamine. The copoly(N5-hydroxyalkyl-L-glutamine) thus prepared is insoluble in water, since the benzyl ester remains in this copolymer. The copoly(α-amino acids) having another functional group were also prepared using aminoalkylsilane. Crosslinked poly(α-amino acids) were prepared by the reaction of the reactive copolymer with a low-molecular-weight polymer of PBLG having one amino group on each end of its main chain which was obtained from the corresponding NCA using p-diaminobenzene as an initiator. Another crosslinked polymer was prepared using an alkyl diamine such as 1,6-diaminohexane or 1,12-diaminododecane as a crosslinking reagent. The crosslinked copoly(α-amino acids) bearing the activated site are able to further react with various compounds having amino groups.
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  • 74
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1417-1422 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reversible isomerization of poly(chloromethylthiirane) and poly(3-chlorothietane) represents a new kind of polymer reaction and a new method of copolymer synthesis. In chloroform, in dichloromethane, or in nitrobenzene the reaction is well described by reversible first-order kinetics. A rate increase of ca. 40% on changing the solvent from chloroform to nitrobenzene is consistent with an isomerization mechanism that involves a rate-determining attack of the backbone sulfur atom on the neighboring carbon-chlorine bond and rapid ring-opening of the thiiranium ion intermediate by chloride ion.
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 609-613 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 633-634 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 77
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1819-1829 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A detailed magic angle spinning 13C-NMR investigation of the intractable polymer prepared by plasma polymerization of toluene and isotopically labeled toluene led to a proposed model for the structure of the polymer and suggested some of the likely processes that occur in the gas phase leading to film formation. From the 13C spectra four resolved resonances permitted the determination of the contribution of nonprotonated and protonated unsaturated as well as methyl and other aliphatic carbons to the polymer structure. Specific 13C isotopic labeling of the methyl and phenyl C-1 toluene carbons in the injected liquid vapor allowed the destination of these carbons in the deposited polymer to be traced. The dominant structure is derived primarily from two precursors: benzyl radical and toluene itself. The 13C data further requires a net saturation of ca. 30% of the toluene double bonds and a net displacement of hydrogen by carbon on ca. 20% of the toluene ring carbons.
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  • 78
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 803-810 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The free radical polymerization of acrylonitrile (AN) initiated by Cu(II) 4-anilino 2-one [Cu(II) ANIPO] Cu(II), 4-p-toluedeno 3-pentene 2-one [Cu(II) TPO], and Cu(II) 4-p-nitroanilino 3-pentene 2-one [Cu(II) NAPO] was studied in benzene at 50 and 60°C and in carbon tetrachloride (CCl4), dimethyl sulfoxide (DMSO), and methanol (MeOH) at 60°C. Although the polymerization proceeded in a heterogeneous phase, it followed the kinetics of a homogeneous process. The monomer exponents were ≥2 at two different temperatures and in different solvents. The square-root dependence of Rp on initiator concentration and higher monomer exponents accounted for a 1:2 complex formation between the chelate and monomer. The complex formation was shown by ultraviolet (UV) study. The activation energies, kinetics, and chain transfer constants were also evaluated.
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  • 79
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Methylacrylamide (NMAAm) was polymerized quantitatively by using di-tert-butyl peroxide as photosensitizer to be, for the most part, incorporated in living poly(NMAAm) radical. The living polymer radical reacted effectively with acrylate monomers to yield block copolymer. Longer alkyl chain of the acrylate monomer caused a decrease in the conversion of the second monomer. Methacrylate monomers, such as methyl methacrylate and cyclohexyl methacrylate, showed relatively low reactivities in comparison with acrylates. Styrene exhibited a much lower conversion. The resulting block copolymers showed different thermochromic behaviors in methyl benzoate from that of poly(NMAAm). This is explained on the basis of the difference between refractive indexes of the block copolymers and poly(NMAAm).
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  • 80
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 865-881 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyimide films based on either 3, 3′, 4, 4′-benzophenone tetracarboxylic acid dianhydride or pyromellitic dianhydride with 4,4′-oxydianiline have been doped with copper(I) and copper(II) complexes. High-quality, flexible, glass-cast films have been obtained which exhibit increased softening temperatures and lower polymer decomposition temperatures. The atmosphere and glass sides of the films are quite different. The copper(I) dopant is oxidized on the air side of the film, while the glass side contains predominantly copper (I). In the copper(II) case most of the copper appears on the air side as a silvery substance in the Cu(II) state. Chemical as well as ion etching can remove this material. Electrical resistivity of the copper(II)-doped films is decreased by three to five orders of magnitude relative to the polymer alone.
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  • 81
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 883-890 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of two phenylated bifunctional monomers, dimethyl 4-(4-(p-aminophenoxy)phenyl)-3,5,6-triphenylphthalate and dimethyl 4-(4-(4-(p-aminophenoxy)phenoxy)phenyl)-3,5,6-triphenylphthlate, was accomplished. Polymerization in solution or by a bulk polymerization procedure yielded a series of low molecular weight phenylated polyimides. The polymers were soluble in chlorinated hydrocarbons and exhibited thermal stabilities comparable to other polyimide systems.
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  • 82
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 937-941 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The structural changes in the potassium graphitide KC24 in its interaction with ∊-caprolactone, γ-butyrolactone and pivalolactone are examined by profilometric measurement and electron scanning microscopy. The interaction of KC24 with a nonpolymerizable lactone-γ-butyrolactone proceeds without delamination of the graphitide. The polymerization of ∊-caprolactone and pivalactone in the interlayer spaces of KC24 leads to destruction of the initiators structure. An increase in the temperature and monomer concentration enhances the delamination of the graphitide.
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  • 83
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure was developed by which polymer colloids can be prepared by polymerizing aerosol droplets of monomers with an initiator in the vapor state. This work describes the formation of poly(p-tertiarybutylstyrene) particles by exposing the corresponding monomer droplets to trifluoromethanesulfonic acid. It was found that the monomer-to-initiator mass ratio is the critical factor in determining the uniformity and morphology of the particles. Under ideal conditions spheres of narrow size distribution are obtained. Otherwise porous particles or soft particles with whiskers may develop. The aerosol was prepared in a falling film generator, but other procedures for producing monomer droplets may be used.
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  • 84
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 999-1012 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polycondensation of the diacid chloride of 2-(3-carboxy vinyl)phenyl-1,3-dioxoisoindoline-5-carboxylic acid with m-phenylenediamine and the diacid chloride of 2-(4-carboxy phenyl)-1,3-dioxoisoindoline-5-carboxylic acid with 1,5-bis(3-aminophenyl)1,4-pentadien-3-one was carried out in polar solvents to produce new unsaturated polyamide-imides. The solution and the thermal, electrical, and a few other properties of the polymers were studies. The polymers were soluble in highly polar solvents. The solubility parameter of the polymers was calculated from the Small's group contribution. The polymers were fairly thermostable and underwent crosslinking creaction when heated, preferably in the presence of a suitable catalyst. The crosslinked polymers were in soluble even in highly polar solvents and possessed higher thermal stability. The swelling behavior of the polymers was studied and the molecular weight between two consecutive crosslinks was determined. X-ray diffraction and the dielectric properties of the polymers and their crosslinked products were also studied.
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  • 85
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1013-1024 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crosslinked polystyrene particles were prepared by Friedel-Crafts suspension crosslinking of polystyrene using 2,4-dichloromethyl-2,5-dimethyl benzene as crosslinking agent. The polymer was dissolved in nitrobenzene and reaction occurred in a 70 wt % aqueous solution of ZnCl2 with poly(vinyl alcohol) as a suspending agent. The spherical particles produced were swollen in toluene, chloroform, and tetrahydrofuran to determine their equilbrium polystyrene volume fraction. Analysis of the crosslinked macromolecular structure gave values of number-average molecular weight between crosslinks of M̄c = 900-5900 increasing as the nominal crosslinking ratio X decreased from 0.75 to 0.0625 mol of crosslinking agent per mole of polystyrene repeating unit. Porosimetric analysis contributed to the understanding of the importance of the pore structure for swelling behavior.
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  • 86
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    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An efficient kinetic method of reactivity ratio measurement for binary copolymerization of gaseous monomers4 that does not require the measurement of copolymer composition and can be applied to the data obtained in a single copolymerization run was modified and applied to olefin copolymerization with heterogeneous Ziegler-Natta catalysts. Estimated r1 and r2 values for pairs like ethylene-propylene and propylene-1-butene agree favorably with published data.
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  • 87
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1097-1110 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new redox couple based on the copper-catalyzed reduction of diaryliodonium salts with benzoins has been used to initiate cationic polymerizations of cyclic ethers and esters. A proposed mechanism for initiation by this redox couple is based on its stoichiometry and on the nature of the products. It was concluded that initiation of polymerization occurs both by direct arylation of the monomer and by protonation by strong Brønsted acids. The polymerization of several typical cationically polymerizable monomers using this new redox initiator were studied.
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  • 88
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1125-1137 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A regenerable dihydronicotinamide immobilized on a macroreticular polystyrene carrier was developed and used in an aqueous medium for the reduction of trifluoroacetophenone to the corresponding alcohol. It was shown that the second-order rate constant for the polymer-bound reagent is significantly lower than that of the low-molecular-weight analog 1-benzyldihydronicotinamide. The observed reaction rate, however, was of the same order of magnitude as that due to enrichment of substrate in the polymeric pores. It was possible to depress the undesired side reactions to 10-15% per reaction cycle, thereby allowing reutilization of the functionalized polymer.
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  • 89
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2451-2461 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 337.1-nm emission of a pulsed nitrogen laser was shown to initiate the crosslinking polymerization of epoxy-acrylate photoresists effectively. We evaluated the extent of curing from the amount of insoluble polymer formed and by the decrease in infrared (IR) absorption of the reactive double bond at 810 cm-1. With the large power density available in the laser pulse (0.5 MW cm-2) rates of polymerization as high as 108 mol L-1 s-1 were observed in the presence of air. Quantum yield measurements indicated that each photon absorbed can create as many as 450 crosslinks; the kinetic chain length was calculated as ca. 4000 double bonds polymerized per initiating radical. During the induction period due to oxygen inhibition each photoinitiator radical consumed 1 O2 molecule. The influence of the monomer and photoinitiator used on the sensitivity of the resin was examined; the best performing formulation contained the epoxy-acrylate oligomer, pentaerythritol triacrylate, as monomer and 2,2 dimethoxy-2-phenyl-acetophenone as photoiniatior. All the formulations studied can be cured by a single 500-kW laser pulse of 8 ns duration, provided that the irradiation is carried out in an inert atmosphere or with a focused laser beam.
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  • 90
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2491-2501 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Values calculated for the activation volume for chain propagation, ΔV
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  • 91
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2529-2534 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article reports a study of the catalytic addition reaction of ferrocene containing dihydrosilane to diacetylenic silicon derivatives. A hypothetical structure based on reaction kinetics and spectral data is presented. The oligomers obtained were studied by TG and DTA from ambient temperature to 1000°C in oxygen atmosphere (80 mL/min). The existance of phenyl groups in the structure of the oligomers makes them less stable than those with derivatives.
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  • 92
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1195-1201 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Our previous NMR investigations of chemically crosslinked polypropylene (PP) were focused mainly on testing the relation between NMR relaxation times as a function of crosslinking compound concentrations and the influence of structural factors found by this method on mechanical and other properties of this polymer.1,2 In these investigations, however, we did not consider the state of mobility of any part of the polypropylene chain under the influence of the network; therefore in this article we have attempted a clarification of this problem.
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  • 93
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1233-1237 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 6 Ill.
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  • 94
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1241-1249 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New polyphthalimidine-forming monomers, 5,5′-(oxydi-p-phenylenedicarbonyl)bis(3-benzylidenephthalide) and the 6,6′-derivative, were synthesized by the Friedel-Crafts reaction of diphenyl ether with 5- and 6-chloroformyl-3-benzylidenephthalide, respectively. The direct polycondensation of these bisphthalides with both aliphatic and aromatic diamines in o-phenylphenol at 200-250°C afforded polyphthalimidines having inherent viscosities of 0.2-1.2 dL/g in almost quantitative yields. Syntheses of aliphatic polyphthalimidines with higher inherent viscosities were also achieved by a two-step procedure involving ring-opening polyaddition and subsequent thermal cyclodehydration. All the polymers were amorphous and readily soluble in N-methyl-2-pyrrolidone (NMP), m-cresol, nitrobenzene, pyridine, and chloroform. Tough and flexible films could be cast from NMP solutions of the polymers. Glass transition temperatures of the polyphthalimidines were in the range of 158-246°C. The thermogravimetry of the aromatic polymers showed 10% weight loss in air and nitrogen at 445-515 and 500-520°C, respectively. The crosslinking reaction of some benzylidenependant polyphthalimidines took place at 300°C through double-bond addition to afford cured polymers with improved thermal stability.
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  • 95
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2617-2628 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Although polymerization of 2,5-dibromothiophene via coupling of the Grignard reagent with organonickel salts was reported in two earlier communications, a detailed examination of reaction variables was not done. This report provides results from variation in the following: time, amount of magnesium, amount of iodine, dilution, and variation in the halide of the monomer. The highest yield was obtained for reactions with 1:1 molar ratio of monomer to magnesium in more concentrated solutions of tetrahydrofuran for a reaction time of 4 h. For variation in the halogen of the monomer the following yield sequence was obtained: I 〉 Br 〉 Cl. The results are compared with the corresponding benzenoid system investigated by Yamamoto. In addition, polymerization studies were carried out with other brominated thiophene monomers. Use of an organic promoter (cis-1,4-dichloro-2-butene) in place of a nickel salt proved successful in the generation of poly(2,5-thienylene).
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  • 96
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1371-1384 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Flash photolysis of copper (II)-bis(amino acid) complexes (amino acids: glutamic acid, serine, or valine) in deaerated aqueous solution produces transient species having absorption maxima at around 350 nm. The transient species are identified as copper (II)-alkyl complexes. In the case of Cu(valine)2 at pH 〉 6.5 formation of Cu(II)-alkyl complex is not observed; this is interpreted to be due to the presence of two bulky methyl groups of the coordinated valine ligand, which hinders the rearrangement. Pseudo-first-order rate constants for the decay of the transients are determined at different pH with varying concentration of amino acid ligand. The free-radical species of the complexes responsible for the initiation of the vinyl polymerization reactions are identified as Cu(I)-coordinated amino acid radicals which are formed in the primary photochemical reaction of the complex. A mechanism for the secondary reactions involving the initiating species consistent with the nature of the product formed and the pH dependence of the decay of the transients is proposed.
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  • 97
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1401-1416 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of studying the radiation curing of methacryloyloxyalkyl carbonates (MC), a new type of oligomer, are presented. These oligomers are notable for their high rates of radiation curing. The radiation yield G(-M) is 2 × 105 for MC and 2 × 104 for triethylene glycol dimethyacrylate. The polymerization rate of MC appeared to be proportional, independent of the conversion degree, to the irradiation dose rate in the power of 0.9-1.0 (for dose rates ranging from 0.4 to 15 rad/s). In regard to the temperature dependence of the polymerization rate of MC for small conversion degrees, two temperature regions with different values of effective activation energy (18-20 kcal/mol and 2 kcal/mol, respectively) were observed. When an irradiated MC sample is being unfrozen, its polymerization occus in the region of devitrification (220-240°K). As distinct from mass polymerization, in the polymerization of MC solutions in acetone and benzol the mobility of growing chains increases so that the bimolecular termination becomes possible and the limiting conversion of double bonds is derived. Rather small irradiation doses necessary for curing MC and the proportionality of the radiation-induced polymerization rate to the dose rate make these oligomers valuable for various industrial applications.
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  • 98
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 1445-1455 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The amount of in-cage and out-of-cage recombination of initiator radicals has been measured by recovering the recombination products of simultaneous decomposition of an unlabeled and a deuterium-labeled initiator. The occurrence of recombination products generated from both an unlabeled and a deuterium-labeled initiator fragment, which can be monitored in a mass spectrometer, indicate out-of-cage recombination. It turned out that in the course of decomposition of dibenzoylperoxide in benzene, biphenyl was not produced by direct recombination of the phenyl radicals originally generated, but rather by interaction with benzene. Upon decomposing azoisobutyronitrile in various solvents, however, both in-cage recombination and out-of-cage recombination were observed. When small amounts of styrene were added to such systems, the initiator radicals tended rather to react with styrene than to undergo out-of-cage recombination.
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  • 99
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 3033-3033 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 100
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    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 3035-3040 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Free-standing polyphenylene films, prepared by the electrochemical oxidation of benzene in an HF-benzene, two-phase system, were investigated. From electron microscope pictures, x-ray diffraction patterns, and infrared (IR) spectra of polyphenylene films and commercial polyphenylene powder it is concluded that the films, which are largely para linked, contain in addition a substantial amount of meta and possibly ortho linkages and are amorphous in nature. Doping with AsF5 increases the electrical conductivity of the otherwise insulating films to 10-4-10-2ohm-1cm-1; doped films are relatively stable in air. The lower conductivity of doped films with respect to reported values for chemically synthesized poly-p-phenylene appears to be the result of the amorphous nature of the films.
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