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  • 2000-2004
  • 1985-1989  (658)
  • 1970-1974
  • 1988  (658)
  • Engineering  (598)
  • Electron microscopy
  • 1
    Electronic Resource
    Electronic Resource
    On the ultrastructure of ependymomas — A semiquantitative analysis of diagnostic criteria in 21 cases with special reference to glycogen as a marker (1988)
    Springer
    Neurosurgical review 11 (1988), S. 67-76 
    Details
    ISSN: 1437-2320
    Keywords: Electron microscopy ; ependymoma ; glycogen ; ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report our results on the ultrastructure of 21 ependymomas and establish the following diagnostic criteria: 1. Glycogen is the most frequently encountered criterion, followed by desmosomes, cilia, basal bodies and microvilli. Fifteen tumors had 3 or more of these features. 2. The allegedly typical nuclear pattern was found in only 6 cases. 3. Special ultrastructural features seen include basement membranes in a mid-thoracic ependymoma. Furthermore we propose the hypothesis that glycogen might be involved in cilia assembly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01795697
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  • 2
    Electronic Resource
    Electronic Resource
    Origin and direction of replication in mitochondrial plasmid DNAs of broad bean,Vicia faba (1988)
    Springer
    Current genetics 14 (1988), S. 163-170 
    Details
    ISSN: 1432-0983
    Keywords: Plant mtDNA ; Electron microscopy ; Restriction enzymes ; Hairpin structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Broad bean (Vicia faba) mitochondrial DNA (mtDNA) includes three circular plasmids: mt-plasmid 1 (1,704 ntp), mt-plasmid 2 (1,695 ntp) and mt-plasmid 3 (1,476 ntp). Partially replicated circular forms of these mt-plasmids have been observed in electron microscope preparations. Restriction enzymes that cleave either mt-plasmid 2 (but not mt-plasmids 1 and 3) or mt-plasmid 3 (but not mt-plasmids 1 and 2) were used to generate linear forms of partially replicated mt-plasmid 2 and mt-plasmid 3 molecules. Analyses of these linearized replicative intermediates, observed by electron microscopy, indicated that in both mt-plasmid 2 and mt-plasmid 3 replication originates at a specific location and proceeds in the same, single direction around the molecules. The replication origins of mt-plasmid 2 and mt-plasmid 3 map close to sequences that can fold into hairpin structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00569340
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  • 3
    Electronic Resource
    Electronic Resource
    Malignant peripheral neuroectodermal tumours of bone other than Askin's neoplasm: characterization of 14 new cases with immunohistochemistry and electron microscopy (1988)
    Springer
    Virchows Archiv 412 (1988), S. 421-430 
    Details
    ISSN: 1432-2307
    Keywords: Neuroectodermal bone tumours ; Immunochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Peripheral neuroectodermal tumours (PNET) of bone are rare and mimick those seen in soft tissue (peripheral neuroepithelioma of soft tissue). Their differential diagnosis from Ewing's sarcoma (Es) is extremely difficult by optical means. Here we report 14 new cases of PNET of bone (other than Askin's neoplasm) located primarily in the limbs, pelvic girdle and scapula. Clinically and radiologically they displayed Ewing's sarcoma-like features: mean age was 14.4 years, male/ female ratio being 3:11. Metastasis was present in 6 cases at diagnosis (5 with bone metastasis). Prognosis was poor; thirteen patients died; only one with a metatarsal located tumour is alive and free of disease. The mean survival rate was 25 months following diagnosis and treatment with radio- and multimodal chemotherapy. Histologically the 14 cases displayed Homer-Wright rosettes and pseudorosette-like structures, as well as a fibrillary background and lobular pattern. Immunohistochemistry revealed positivity in a number of neural markers when using paraffin-embedded material: NSE, B-2-microglobuline, HNK-1 (leu-7) and E-36 antibodies. At EM level the cell cytoplasms evidenced dense-core granules with neurosecretion, neurotubules and intermediate filaments like those seen in peripheral neuroepithelioma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750576
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  • 4
    Electronic Resource
    Electronic Resource
    Alveolar soft part sarcoma (1988)
    Springer
    Virchows Archiv 412 (1988), S. 499-513 
    Details
    ISSN: 1432-2307
    Keywords: Alveolar soft part sarcoma ; Cytology ; Electron microscopy ; Immunohistochemistry ; DNA analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The type, differentiation and histogenesis of the tumor cells of alveolar soft part sarcoma (ASPS) have been analyzed in a series of ten cases by a light-microscopic, ultrastructural, immunohistochemical and cytologic investigation and quantitative DNA analysis. Four tumors deviated from ordinary ASPS: three were wholly or partly of the so-called pleomorphic variant of ASPS and a fourth tumor showed calcifications of the psammoma body type. The ultrastructural findings and immunohistochemical demonstration of desmin supported the hypothesis of a rhabdomyomatous differentiation and gave no support to epithelial (negative immunoreactions for cytokeratins, epithelial membrane antigen, HMFG-1 and -2, tissue polypeptide antigen (TPA)) or neuroectodermal (negative for S-100 protein, glial fibrillary acidic protein, neurofilaments) differentiation. The negative immunoreactions for vimentin and myoglobin and the positive reaction for neuron specific enolase (NSE) do not exclude a rhabdomyomatous differentiation since in rhabdomyosarcomas the undifferentiated rhabdomyoblasts generally contain vimentin and the differentiated tumor cells contain myoglobin and rhabdomyosarcoma has previously been reported as being positive for NSE. The production of external lamina material peripherally in the tumor cell nests and around vessels in the vascular septa was demonstrated both ultrastructurally and by immunohistochemistry using antibodies against collagen IV and laminin. The cytologic appearance in smears obtained by fine-needle aspiration from a case of the pleomorphic variant showed some resemblance to that of a carcinoma. The seven tumors with an ordinary cell appearance were found to show a diploid DNA-distribution at a quantitative analysis performed on paraffin sections, while the three tumors wholly or partly of the pleomorphic type showed an additional tetraploid peak.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00844286
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  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructural and immunohistochemical findings in oral hairy leukoplakia (1988)
    Springer
    Virchows Archiv 412 (1988), S. 533-542 
    Details
    ISSN: 1432-2307
    Keywords: Hairy leukoplakia ; Electron microscopy ; Epstein-Barr virus ; Candida albicans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of HL from the lateral border of the tongue of male homosexual AIDS patients were investigated by thin section electron microscopy. Keratinocytes contained condensed chromatin in their pyknotic nuclei and a few organelles in the oedematous cytoplasm. Chromatin was in close association to the nuclear membrane and showed a punched-out appearance. Particles typical of the herpes virus group were abundant in the upper two thirds of the epithelium in all three cases. Virus particles were seen frequently in the nuclei of the ballooned keratinocytes, but rarely in cells containing Candida albicans. Viral nucleocapsids were observed budding at the inner nuclear membrane, thereby acquiring the prospective viral envelope. Complete, enveloped virions were found in the endoplasmic reticulum and in the extracellular space. These virions were identified immunohistochemically as Epstein-Barr virus (EBV) using two monoclonal antibodies directed against EBV capsid and membrane antigen, respectively. Candida albicans was observed in the stratum corneum and in the upper layer of the stratum spinosum. Special cytoplasmic tubular structures arranged in parallel bundles were found in koilocytotic cells in addition to characteristic membrane structures composed of undulating convoluted membranes. Epithelial basement membranes were always intact.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00844289
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  • 6
    Electronic Resource
    Electronic Resource
    Ultrastructural features of acute monoblastic leukaemia cells: A multivariate morphometric analysis (1988)
    Springer
    Virchows Archiv 414 (1988), S. 21-27 
    Details
    ISSN: 1432-2307
    Keywords: Monoblastic leukaemia ; Electron microscopy ; Morphometry ; Multivariate statistics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphometric studies were carried out on five ultrastructural measures of size or quantity of some of the intracellular organelles in monoblasts obtained from six patients diagnosed as having acute monoblastic leukaemia and also on monocytes from six normal controls. The morphometric measures were analysed using a one way multivariate analysis of variance (MANOVA) to see whether acute monoblastic leukaemic cells differed from those of normals. It was found that there was a highly significant decrease both in the surface to volume ratio of mitochondria and also in the surface to volume ratio of the nucleus. The possible physiological significance of these structural changes is stressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00749734
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  • 7
    Electronic Resource
    Electronic Resource
    Osteosarcoma with a clear-cell component (1988)
    Springer
    Virchows Archiv 412 (1988), S. 273-279 
    Details
    ISSN: 1432-2307
    Keywords: Osteosarcoma ; Clear cell ; Histopathology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The reports concerns the light microscopical and ultrastructural findings obtained in three conventional osteosarcomas with an unusually high admixture of clear cells, whose presence appeared to be responsible for the marked change in the histological pattern of these tumours. In the tumours with a prevailing fibroblastic component the clear cells were either irregularly scattered throughout the tumour in the form of small groups, or they formed large groups sharply demarcated against the fusicellular areas of the tumours. In two cases it was shown that their cytoplasm contained exaggerated glycogen deposits accompanied by the formation of glycogen-containing phagolysosomes and occasional empty vacuoles. In the third case the clear cells showed vacuolar degeneration with numerous single-membrane-bound, empty vacuoles. In contrast to the clear-cell chondrosarcoma we did not find S-100 protein in clear cells of our osteosarcomas. Such findings could be particularly significant in the differential diagnosis of bone tumours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00737152
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  • 8
    Electronic Resource
    Electronic Resource
    Oncocytomas and null cell adenomas of the human pituitary: Morphometric and in vitro functional comparison (1988)
    Springer
    Virchows Archiv 413 (1988), S. 333-339 
    Details
    ISSN: 1432-2307
    Keywords: Electron microscopy ; Morphometry ; Null cell adenoma ; Oncocytoma ; Pituitary adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this study, light microscopic and ultrastructural morphometric features of oncocytomas and null cell adenomas were compared and the morphometric data were correlated with in vitro endocrine activity. All tumours were unassociated with clinical or biochemical evidence of hormone excess and were diagnosed as oncocytomas or null cell adenomas, using histology, immunohistochemistry and electron microscopy. In oncocytomas, when compared with null cell adenomas, light microscopic morphometry revealed that total cell areas were significantly larger and nuclear cytoplasmic ratios were smaller due to an increase in cytoplasmic areas. Ultrastructural morphometry disclosed an abundance of mitochondria in oncocytomas. Absolute volumes of cytoplasmic organelles per cell were not reduced in oncocytomas compared with those of null cell adenomas. These results indicate that accumulating mitochondria do not replace other cytoplasmic organelles, and furthermore that the functional potential of oncocytomas is not lost. In vitro study demonstrated the production of pituitary hormones, primarily gonadotropins in oncocytomas and null cell adenomas. It can be concluded that oncocytomas, which represent the final stage of oncocytic transformation, have a close relationship with null cell adenomas based on morphometric comparison as well as in vitro studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00783026
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  • 9
    Electronic Resource
    Electronic Resource
    Small cell neuroendocrine carcinoma of the urinary bladder (1988)
    Springer
    Virchows Archiv 413 (1988), S. 505-512 
    Details
    ISSN: 1432-2307
    Keywords: Neuroendocrine differentiation ; Immunohistochemistry ; Electron microscopy ; Small cell undifferentiated bladder carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Small cell carcinoma with the histological appearance of pulmonary small cell carcinoma is a rare tumour in the urinary bladder. In previous case reports the neuroendocrine nature of small cell bladder carcinoma has been accepted, but on review the evidence for true neuroendocrine differentiation appears unsatisfactory. In this study the histological, immunohistochemical and ultrastructural characteristics of three cases of small cell carcinoma of the urinary bladder are described. Ultrastructurally, the cytoplasm of all three tumours contained neurosecretory-type granules and each of the tumours demonstrated positive immunoreaction for two or more neuroendocrine markers, from a panel including neuron-specific enolase, chromogranin A, Leu-7, bombesin and synaptophysin. Although the combination of ultrastructural and immunohistochemical examination obviously offers the strongest evidence in establishing neuroendocrine differentiation, it is argued that immunohistochemistry alone may also yield important information in demonstrating a neuroendocrine nature, provided that at least neuron-specific enolase and synaptophysin are included as markers. The clinical relevance of identifying neuroendocrine differentiation in small cell bladder carcinoma is suggested by the favourable response to combination chemotherapy in two of our cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750391
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  • 10
    Electronic Resource
    Electronic Resource
    Do folliculo-stellate adenomas of the pituitary gland exist or are they intrasellar meningiomas? (1988)
    Springer
    Acta neuropathologica 77 (1988), S. 219-223 
    Details
    ISSN: 1432-0533
    Keywords: Meningioma ; Folliculo-stellate cell ; Pituitary neoplasm ; Electron microscopy ; Immunochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A tumor arising in the pituitary fossa and having some of the histological and ultrastructural features of a recently described tumor, purportedly originating from the folliculo-stellate cells of the anterior pituitary, is presented. The results of our ultrastructural and immunohistochemical studies, however, favored a meningeal origin and suggested that the neoplasm was most likely a secretory meningioma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687435
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  • 11
    Electronic Resource
    Electronic Resource
    Structural changes in the rat brain after carotid infusions of hyperosmolar solutions (1988)
    Springer
    Acta neuropathologica 77 (1988), S. 5-13 
    Details
    ISSN: 1432-0533
    Keywords: Blood-brain barrier ; Hyperosmolar solutions ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Infusion of hypertonic solutions into the carotid artery is one method by which the blood-brain barrier (BBB) can be opened transiently in experimental animals. This technique has also been tried in clinical situations in which an enhanced uptake of intravenously injected chemotherapeutic drugs into the brain is desired. We have previously found that infusion of hypertonic mannitol or urea into the carotid artery of the rat, leading to a BBB opening, is associated with light microscopic signs of cellular damage in the brain parenchyma. An electron microscopic study has now been made to obtain more detailed information about the events taking place in the rat brain 1 to 72 h after an intracarotid infusion of hyperosmolar solution of mannitol. Toluidine blue-stained semithin epon sections were also available for high-resolution light microscopy of brain samples from urea-infused animals. Intravenously injected Evan's blue dye was used to confirm that BBB opening had occurred as a consequence of the carotid infusions. The infused hemispheres had numerous structural changes. The dominating light microscopic alteration was the presence of multifocal lesions in the gray or the white matter with closely packed microvacuoles causing status spongiosus. Ultrastructurally the microvacuoles corresponded to very pronounced watery swelling of astrocytic processes and to a minor degree to expansion of dendrites and axons. There was also a light or moderate perivascular astrocytic swelling. In the “spongy” lesions as well as occasionally in non-vacuolated parts of the cerebral cortex, there were collapsed electron-dense neurons with pronounced mitochondrial alterations such as severe swelling associated with rupture of christae. Rats with a survival period of 24 h or 72 h showed several disintegrating neurons and accumulation of macrophages. This study shows that carotid infusion of hypertonic mannitol in the rat may cause pronounced neuronal changes as well as multifocal astrocytic swelling. The severity of the nerve cell changes and the presence of macrophages indicate that some of the alterations are irreversible and thus, such a procedure may not be as safe as previously suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688236
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  • 12
    Electronic Resource
    Electronic Resource
    Nerve cell injury in the brain of stroke-prone spontaneously hypertensive rats (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 227-237 
    Details
    ISSN: 1432-0533
    Keywords: Stroke-prone spontaneously hypertensive rats ; Blood-brain barrier ; Brain edema ; Nerve cell injury ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The brain lesions in stroke-prone spontaneously hypertensive rats (SHRSP) are characterized by multifocal microvascular and spongy-cystic parenchymal alterations particularly in the gray matter. An essential feature of the lesions is the presence of edema with massive extravasation of plasma constituents as evidenced by specific gravity measurements, Evans blue technique and immunohistochemistry. The nerve cell injury occurring in the brain lesions in SHRSP is further characterized by light and electron microscopy in the present study. Two types of neuronal changes were seen within the blood-brain barrier (BBB) leakage sites. A small number of neurons with dark condensed nucleus and cytoplasm were found most often at the periphery of recent lesions. The majority of injured neurons were pale and showed intracellular edema confined to the dendrites and perikarya sparing axons and synapses. Their nuclei were weli preserved with finely dispersed chromatin. The swollen and watery cell processes of neurons and astrocytes gave a spongy appearance to the neuropil. The intracellular edema seemed to result in cytolysis. The results suggest that primary anoxiaischemia is not the major pathogenetic mechanism behind the nerve cell injury in severely hypertensive SHRSP, rather it is the massive BBB leakage and consequent brain edema that causes cytolytic destruction of neurons. Secondary focal ischemia as a consequence of occlusion in microvessels may, however, contribute to the nerve cell destruction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687769
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  • 13
    Electronic Resource
    Electronic Resource
    The ultrastructural organization of the isthmic nucleus in Xenopus (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 325-330 
    Details
    ISSN: 1432-0568
    Keywords: Isthmic nucleus ; Electron microscopy ; Tectal ablation ; Xenopus ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The isthmic nucleus (IN) of the frog brain forms a linkage, relaying visual information from one tectum to the other. It receives afferent input from the tectum of the same side and projects bilaterally to both tecta. The ultrastructural features of the tecto-isthmic synaptic connections were studied in young postmetamorphic Xenopus frogs. Most synaptic profiles in the isthmic nucleus have spheroidal vesicles and an asymmetric zone of apposition. Frequently, synaptic glomeruli consisting of up to 8 terminal boutons surrounding a shaft dendrite were observed. The syanptic density in the rostral IN was slightly higher than in the middle or caudal portions. Partial deafferentation by transection of the tectoisthmic pathway or total deafferentation by removal of the tectum was followed by a widespread degeneration of terminals in the ipsilateral IN. In the former case, the density of synapses in the IN decreased initially by about 64%, and then increased by 30 days after operation to about 50% of the normal synaptic density. After tectal removal, all the terminal boutons in the isthmic neuropil degenerated by 3 days after operation. These studies, along with recent findings, indicate that most, if not all, of the afferent fibres to IN are of tectal origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315840
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  • 14
    Electronic Resource
    Electronic Resource
    Fine structural survey of Gudden's tegmental nuclei in the rat: cytology and axosomatic synapses (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 485-493 
    Details
    ISSN: 1432-0568
    Keywords: Ventral tegmental nucleus of Gudden ; Dorsal tegmental nucleus of Gudden ; Quantitative morphometric study ; Synaptic organization ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fine structure of neuronal somata and axosomatic synapses in each subnucleus of Gudden's tegmental nuclei was studied by use of electron microscopy. The pars principalis of the ventral tegmental nucleus of Gudden (TVP) is composed of oblong or triangular, medium sized neurons (11.8x22.6 μm, 211.4 μm2) containing many mitochondria, lysosomes, Golgi apparatus, and rough endoplasmic reticulum composing Nissl bodies. The light oval nucleus with a prominent nucleolus is centrally situated, and indentations of its nuclear envelope are recognized in all neurons. The neuron in the pars ventralis of the dorsal tegmental nucleus of Gudden (TDV) is similar to that in the TVP, but its average size is significantly smaller (10.0x18.8 μm, 151.4 μm2), and its organelles are also less well developed. The pars dorsalis of the dorsal tegmental nucleus of Gudden (TDD) is composed of spindle shaped, small neurons (6.9x16.2 μm, 85.1 μm2) characterized by their irregular shaped nucleus with its invaginated envelope. These neurons have a thin rim of cytoplasm, poorly developed organelles and no Nissl bodies. The average number of axosomatic terminals in a sectional plane is 9.9 in the TVP, 9.6 in the TDV and 2.6 in the TDD, and the bouton covering ratio is 24.3% in the TVP, 26.5% in the TDV and 7.4% in the TDD. The respective percentages of round, flat and pleomorphic type axosomatic terminals were estimated, and the flat type terminals were found to be dominant in the TVP, the pleomorphic type terminals in the TDV, and the round type terminals in the TDD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305136
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  • 15
    Electronic Resource
    Electronic Resource
    Quantitative electron microscopic observations on the non-neuronal cells and lipid droplets in the posterior funiculus of the kitten after dorsal rhizotomy (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 95-105 
    Details
    ISSN: 1432-0568
    Keywords: Electron microscopy ; Glial cells ; Perivascular cells ; Lipid droplets ; Wallerian degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Kittens were subjected to lumbosacral dorsal rhizotomies at the age of 6–8 days postnatally. After postoperative survival times of 1–25 days the number of non-neuronal cells and lipid droplets in each cell type in the posterior funiculus at L1 were counted at the ultrastructural level. Intact control animals were analyzed in the same way. The number of astrocytes and oligodendrocytes decreased with increasing postoperative survival time in the degenerating zone. This was also the case in the white matter of control animals with increasing age of sacrifice. However, in the degenerating zone of operated animals the decrease was more extensive for oligodendrocytes starting at 5 days after surgery, and possibly also for astrocytes at 25 days postoperatively. The number of microglial cells in the degenerating zone was markedly increased 2–10 days after surgery compared to the controls. The number of non-pericytic perivascular cells seemed to be somewhat increased from 9 days after surgery, while the number of pericytes remained unchanged during the experimental period. Lipid droplets in the degenerating white matter were mainly located in microglial cells and astrocytes and only to a small extent in nonpericytic perivascular cells. These findings suggest that lipid material produced during anterograde fiber degeneration in the immature white matter is mainly metabolized in glial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02463643
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  • 16
    Electronic Resource
    Electronic Resource
    Ultrastructure of preimplantation rabbit embryos exposed to visible light and room temperature (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 229-241 
    Details
    ISSN: 1432-0568
    Keywords: Room temperature ; Visible light ; Preimplantation embryos ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Early cleavage stage embryos (day 1 p.c.) and morulae (day 3 p.c.) of rabbits were exposed to visible (standard) lighting (1600 lx) and room (standard) temperature (23°C) during a 24 h in-vitro culture. Control embryos were cultured in darkness at 37°C. Development was assessed by light and electron microscopy as well as by the cytochemical demonstration of glycogen. In day 1 and day 3 embryos standard temperature induced swelling of the SER and Golgi complex vesicles. Major changes in day 1 embryos consisted of smallish microtubules-like crystalloids, and in day 3 embryos of unusually large SER vesicles. In both embryonic ages cleavage rate and development was more retarded by standard temperature than by standard lighting. Standard lighting, however, led to distinct signs of degeneration and cell death. The mode of cell damage seemed to be different in light exposed early cleavage stages and morulae: In day 1 embryos cytoplasmic degeneration was predominant while the majority of cells in day 3 embryos died by apoptosis. Despite clear indications of cell damage, cleavage rate was not notably impaired compared with non-exposed controls. Glycogen increased during development from cleavage stages to early blastocysts. The distribution was not changed either by exposure to standard temperature nor by standard lighting. The results demonstrate that day 1 embryos were clearly more susceptible to lighting whereas day 3 embryos were more affected by temperature. The mode of damage exerted by both the physical environmental factors was different. Reduction to standard temperature interfered mainly with the organization of the cytoskeleton and intracellular transport of organelles, while exposure to standard lighting led to cell degeneration and death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318226
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  • 17
    Electronic Resource
    Electronic Resource
    Heterogeneities of the islets in the rabbit pancreas and the problem of “paracrine” regulation of islet cells (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 297-307 
    Details
    ISSN: 1432-0568
    Keywords: Rabbits ; Islands of Langerhans ; Electron microscopy ; Immunohistochemistry ; Regulation of islands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In addition to “external” signals conveyed by the circulation or the nervous system, the pancreatic islets obviously are regulated also by “internal” (intra-islet) signals, e.g. by the islet hormones: insulin (B-), glucagon (A-), and somatostatin (D-) cells are able to affect the secretion of the heterologous cell types. It is, however, unclear whether this functional cooperation between islet cells occurs by an intercellular route (paracrinia sensu strictore), by intraislet “portal” vessels, or by the systemic circulation. These likely interactions are limited by islet anatomy. To identify the anatomical basis for the mutual functional relationships between the islet cells, islets of Langerhans in the rabbit pancreas were completely analyzed in immunostained serial semithin (0.5 μm) sections. The islets were found to be largely heterogenous. They were classified in three basic types: a) polycellular islets, composed of all established endocrine cells, and including two subtypes of islets, b) bicellular islets, containing only B- and A-cells or B- and D-cells, and c) monocellular islets, exclusively made up of B-cells. Concerning the modes of paracrine regulation of islet cells, the findings suggest primarely an endocrinous route of transport of the islet peptides to heterologous endocrine cells. The corresponding functional cooperation between islet cells probably is mediated rather by the systemic circulation than by intra-islet portal vessels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698661
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  • 18
    Electronic Resource
    Electronic Resource
    Light and electron microscopic investigation of the rat placenta after cadmium administration during pregnancy (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 345-351 
    Details
    ISSN: 1432-0568
    Keywords: Cadmium, Placenta (rat) ; Morphometry ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphology of the rat placenta was studied after exposure to cadmium chloride during pregnancy, using optimal fixation conditions. In contrast to previous observations, no differences were observed after cadmium administration in relative volume densities of trophoblastic tissue, maternal lacunae, fetal capillaries and connective tissue, nor in trophoblastic thickness or other morphometric features. At the ultrastructural level, the amount of glycogen in trophoblast layer II was elevated in cadmium exposed rats, but other electron microscopic features (amount and localization of lipid, degenerative vesicles, thickness and general appearance of the trophoblastic and endothelial layers and thickening or multiplication of the basal lamina) were not changed. Results obtained from the present experiments do not support the suggestion that cadmium is responsible for structural changes in the placentae of human smokers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698665
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  • 19
    Electronic Resource
    Electronic Resource
    Quantitative assessment of taurine-like immunoreactivity in different cell types and processes in rat cerebellum: an electronmicroscopic study based on a postembedding immunogold labelling procedure (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 407-421 
    Details
    ISSN: 1432-0568
    Keywords: Taurine ; Immunocytochemistry ; Quantification ; Electron microscopy ; Cerebellum ; Purkinje cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrathin sections of plastic-embedded rat cerebella were incubated with an antiserum against conjugated taurine and subsequently treated with a secondary antibody coupled to colloidal gold. The density of gold particles in various cellular profiles was calculated with the assistance of a computer. In the cerebellar cortex the highest density was found in the somata, dendrites, and dendritic spines of the Purkinje cells, supporting parallel light-microscopical observations in postembedding stained semithin sections from the same tissue blocks. The remaining profiles could be divided into three groups according to their immunolabelling intensity, in descending order: 1) somata and processes of granule and Golgi cells; 2) somata and processes of stellate, basket, and glial cells, and 3) mossy fiber terminals. In a representative experiment, the structures in the first and second groups showed gold particle densities in the range of 19–25%, and 4–11%, respectively, of that in the Purkinje cell somata (values corrected for background) whereas the particle density in the mossy fiber terminals was not significantly above background level. In the cerebellar nuclei, taurine-like immunoreactivity was concentrated in terminals that typically established symmetric or intermediate type contacts with weakly labelled dendrites and cell bodies. These terminals, which shared the ultrastructural features of Purkinje cell terminals, showed an average gold particle density that was about 60% higher than that of the Purkinje somata. For specificity control, ultrathin sections containing a series of different amino acid conjugates were incubated in the same drops of sera as the tissue sections. The highly selective labelling of the taurine conjugate indicated that the distribution of gold particles in the tissue was not confounded by crossreactivity with GABA, glutamate or other common amino acids but adequately reflected the distribution of fixed taurine. For additional control of specificity, the taurine antiserum was applied to the soluble fraction of a rat brain extract separated by thin layer chromatography. In this system the taurine antiserum stained a single spot that comigrated with free taurine. The present results suggest that all cell types and processes in the rat cerebellum (with the exception of the mossy fiber terminals) contain taurine. However, the concentration of taurine appears to vary considerably among the different cell types and may also differ between different parts of the same neuron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306047
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  • 20
    Electronic Resource
    Electronic Resource
    Proliferation of rat intraspinal Schwann cells following tellurium intoxication (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 624-627 
    Details
    ISSN: 1432-0533
    Keywords: X-Irradiation ; Intraspinal Schwann cell ; Myelin ; Autoradiography ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A stable population of intraspinal Schwann cells, which developed follwing early postnatal irradiation of the spinal cord, was challenged by the addition of tellurium (Te) to the diet beginning at 30 days of age. Schwann cells incorporating [3H]thymidine were identified by 1 μm autoradiographs and by conventional electron microscopy of adjacent thin sections. Autoradiographs of areas with Schwann cell myclination showed extensive labelling of cells in the Te-fed animals. In contrast, control animals which were not fed Te showed little evidence of labelled Schwann cells. These data indicate that Schwann cells in the intraspinal environment show a proliferative response to the presence of Te in the rat's diet, as do Schwann cells in their normal extraspinal milieu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689602
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  • 21
    Electronic Resource
    Electronic Resource
    Abnormal amianthoid collagen fibers in meningioma (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 638-639 
    Details
    ISSN: 1432-0533
    Keywords: Meningioma ; Electron microscopy ; Collagen ; Amianthoid fibers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electron microscopic examination of a spinal meningioma demonstrated broad zones with large amianthoid collagen fibers in the tumor. Normal native collagen fibrils were found in small scattered clumps particularly around the blood vessels in the tumor. Such abnormal large collagen fibrils have not been seen previously in meningiomas. The significance of the amianthoid fibers is unknown. The only other unusual feature of the tumor was that it had many pale-staining cells by light microscopy and was classified as a clear cell variant of meningioma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00689605
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  • 22
    Electronic Resource
    Electronic Resource
    Morphological study of peripheral nerve changes induced by chloroquine treatment (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 253-260 
    Details
    ISSN: 1432-0533
    Keywords: Chloroquine ; Peripheral neuropathy ; Nerve biopsy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nerve biopsies were performed in four patients with suspected chloroquine induced neuromyopathy. Three of the patients were treated with high doses of chloroquine for connective tissue disease, while one patient was taking this drug as malaria prophylaxis. Morphological studies demonstrated the presence of segmental demyelination and remyelination in all cases. Cytoplasmic inclusions were observed in Schwann cells, in perineurial and endothelial cells, and in some interstitial cells. They were never observed within axons. Occasional curvilinear profiles were seen in perineurial and Schwann cells. Perineurial calcifications were observed in two cases. The results of this morphological study suggest that chloroquine neuropathy is essentially due primary involvement of Schwann cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690533
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  • 23
    Electronic Resource
    Electronic Resource
    Human immunodeficiency virus (HIV)-related chronic relapsing inflammatory demyelinating polyneuropathy with multifocal unusual onion bulbs in sural nerve biopsy (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 529-534 
    Details
    ISSN: 1432-0533
    Keywords: HIV-related relapsing polyneuropathy ; Intrathecal HIV antibodies ; Nerve biopsy ; Electron microscopy ; Schwann cell morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This is obviously the first report on a case with a spontaneous sensu strictu relapsing variant of human immunodeficiency virus (HIV)-related polyneuropathy. Its manifestation preceded LAS. Intrathecal HIV-antibodies developed between the most severe third and fourth episode. Analysis of sural nerve biopsy was consistent with a multifocally accentuated chronic inflammatory demyelination, characterized by unusual onion bulb-like Schwann cell formations with irregular voluminous layers, electron density, aggregation of filaments, multiple indented nuclei, and numerous enclosed collagen pockets. A direct or immune-mediated indirect specific influence on Schwann cell morphology by HIV might be discussed. Virus-like particles and ultrastructural markers of HIV were not detectable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687143
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  • 24
    Electronic Resource
    Electronic Resource
    A novel intradural extramedullary spinal cord tumor in young dogs (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 402-410 
    Details
    ISSN: 1432-0533
    Keywords: Spinal cord tumor ; Dog ; Electron microscopy ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied an unusual, spontaneous, intradural extramedullary spinal cord tumor in 12 dogs. Animals presented with paraparesis and ataxia early in life (11/12 ranged from 6 to 38 months of age) suggesting that these tumors may be congenital. Various breeds of dogs were represented with four cases in German Shepherds and three in retrievers; there was no sex predisposition. Post-mortem examinations revealed a single intradural mass consistently located between T10 and L2, which produced extensive compression of the spinal cord. Metastasis was never observed and significant pathological changes in other organs were lacking. Microscopic examination revealed solid sheets of ovoid to fusiform cells interspersed with areas of acinar and tubular differentiation. Some areas were rarified and focal squamous metaplasia was observed. Ultrastructural features included the presence of a continuous basal lamina, junctional complexes, microvilli and occasional cilia at the apices of acinar complexes. Immunocytochemical studies did not support a neurectodermal origin. At least 13 case reports of this entity have been previously published and have been designated ependymomas, medulloepitheliomas and neuroepitheliomas. A recent case was diagnosed as a nephroblastoma and we feel that this is an interesting and provocative diagnosis. These tumors could result from remnants of renal primordium which becomes trapped between the dura and the developing spinal cord. However, firm evidence of such a histogenesis is not yet at hand.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687794
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  • 25
    Electronic Resource
    Electronic Resource
    Ultrastructural analysis of neurofibrillary tangles of Alzheimer's disease using computerized digital processing (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 519-522 
    Details
    ISSN: 1432-0533
    Keywords: Alzheimer's disease ; Neurofibrillary tangle ; Paired helical filament (PHF) ; Electron microscopy ; Computerized digital processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of neurofibrillary tangles of Zlzheimer's disease was analyzed by computerized digital processing of electron micrographs. Processing of the electron micrographs consists of four steps: digitizing the electron micrograph, Fourier transformation, noise filtering and inverse Fourier transformation and Laplacian operation. In the present study, we have confirmed that neurofibrillary tangles are composed of a pair of helical filaments (PHF), which appear characteristically as an unbranched rigid structure. The periodicity of PHF is 78nm on the diffractogram. The dimensions of PHF obtained by our analysis, although basically similar to those described earlier by other investigators using conventional techniques, more precisely defines its structural conformation. We have also demonstrated that the spatial relationship of two filaments appears symmetrical after two-way tilting of the specimen about the axis of rotation. Our observations emphasize the importance of digital image processing as an effective tool for structural analytical research in biology and medicine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687141
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  • 26
    Electronic Resource
    Electronic Resource
    Ultrastructural pathology of dermal axons and Schwann cells in lysosomal diseases (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 489-495 
    Details
    ISSN: 1432-0533
    Keywords: Dermal nerves ; Electron microscopy ; Lysosomal diseases ; Terminal axons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Skin tissue specimens, obtained from 60 patients afflicted with a diverse range of lysosomal disorders revealed two groups of lesions within dermal axons, largely unmyelinated ones, particularly within axonal terminals: (1) non-specific mitochondria and dense bodies often enlarging the axonal terminal; and (2) disease-specific lysosomal residual bodies, the latter less frequent depending on the incidence and type of lysosomal disorders, i.e., largely only seen in GM2-gangliosidosis due to hexosaminidase A deficiency and mucolipidosis IV, while the spectrum of lysosomal residual bodies in Schwann cells appeared more variegated, especially due to the occurrence of vacuolar lysosomal residual bodies which were never seen within axons. The most frequent location of abnormal intraaxonal constituents in terminal axons indicates a functionally and morphologically impaired retrograde axonal transport but provides no further evidence as to whether the respective parent nerve cell body has also accumulated lysosomal residual bodies. When studying biopsied skin specimens for diagnosis, axonal terminals beneath the epidermis, about sweat glands, and among smooth muscle cells, ought to be incorporated into a comprehensive electron microscopic examination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686388
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  • 27
    Electronic Resource
    Electronic Resource
    The postsynaptic targets of substance P-immunoreactive terminals in the rat neostriatum with particular reference to identified spiny striatonigral neurons (1988)
    Springer
    Experimental brain research 70 (1988), S. 361-377 
    Details
    ISSN: 1432-1106
    Keywords: Neostriatum ; Substance P ; Immunocytochemistry ; Golgi-impregnation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Substance P-immunoreactive boutons were examined in the electron microscope in sections of the rat neostriatum that contained retrogradely labelled striatonigral neurons and/or Golgi-impregnated medium-size densely spiny neurons. The postsynaptic targets of the immunoreactive boutons were characterized on the basis of ultrastructural features, their projection to the substantia nigra and/or their somato-dendritic morphology. Substance P-immunoreactive axonal boutons formed symmetrical synaptic specializations. Of a total of 233 randomly identified synaptic boutons 72.5% made contact with dendritic shafts, 15% with dendritic spines and 10.7% with perikarya. The ultrastructural characteristics of some of the postsynaptic neuronal perikarya were consistent with their identification as striatal interneurons. Similarly, the observation of some of the substance P-containing terminals in contact with spines, spine-bearing dendritic shafts and perikarya with the ultrastructural characteristics of medium-size densely spiny neurons suggested that one of the targets of substance P-positive terminals are striatal projection neurons. Direct evidence for this was obtained in sections from rats that had received injections of horseradish peroxidase conjugated with wheatgerm agglutinin in the substantia nigra. The perikarya of retrogradely labeled striatonigral neurons were found to receive symmetrical synaptic input from substance P-positive boutons. Ultrastructural analysis of Golgi-impregnated medium-size densely spiny neurons, some of which were also retrogradely labeled from the substantia nigra, demonstrated directly that this class of neuron was postsynaptic to the substance P-immunoreactive boutons. The combination of Golgi-impregnation with substance P-immunocytochemistry made it possible to study the pattern or topography of the substance P-positive input to medium size densely spiny neurons. The substance P-containing boutons made contact predominantly with perikarya and dendritic shafts. This pattern of input is markedly different from that of other identified inputs to medium-size densely spiny neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248361
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  • 28
    Electronic Resource
    Electronic Resource
    The cholinergic innervation of the rat substantia nigra: a light and electron microscopic immunohistochemical study (1988)
    Springer
    Experimental brain research 72 (1988), S. 178-184 
    Details
    ISSN: 1432-1106
    Keywords: Choline acetyltransferase ; Immunocytochemistry ; Substantia nigra ; Pedunculopontine tegmental nucleus ; Acetylcholine ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Putative cholinergic axons and synaptic endings were demonstrated in the substantia nigra (SN) of the rat by light and electron microscopy on the basis of the localization of choline acetyltransferase (ChAT) immunoreactivity. The distribution of ChAT immunoreactivity in the SN as demonstrated by light microscopy revealed a modest network of ChAT-immunoreactive beaded axons in the SNc, in comparison to a relatively sparse distribution in the SNr. These axonal profiles were most dense in the middle of the rostral-caudal extent of the SNc and appeared to be concentrated in the middle third of the medial-lateral extent. By electron microscopy, unmyelinated, small diameter (0.25 μm) ChAT-immuno-reactive axons were observed interspersed among numerous other non-immunoreactive axons in the SNc. ChAT-immunoreactive synaptic endings were observed in juxtaposition to small caliber (0.5 μm) non-immunoreactive dendrites, and contained numerous spheroidal synaptic vesicles and occasional mitochondria. Synaptic contact zones were characterized by an accumulation of synaptic vesicles along the presynaptic membrane, and a prominent postsynaptic densification producing an asymmetrical pre-/postsynaptic membrane profile typical of excitatory synapses. These findings provide direct evidence for a cholinergic innervation of the SN, and suggest that this input may have an excitatory effect on neuronal elements in the SNc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248513
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  • 29
    Electronic Resource
    Electronic Resource
    Changes in microglial cell numbers in the spinal cord dorsal horn following brachial plexus transection in the adult rat (1988)
    Springer
    Experimental brain research 73 (1988), S. 61-68 
    Details
    ISSN: 1432-1106
    Keywords: Microglia ; Dorsal horn ; Nerve lesion ; Light microscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of peripheral nerve transection on the size of the microglial cell population in cytoarchitecturally distinct regions of the spinal cord dorsal horn of rats was evaluated at selected intervals 2 through 35 days after unilateral brachial plexotomy. The identification of cells was verified by electron microscopic examination of a representative random sample of cells included in the counts. Microglial cell numbers were increased in laminae I, II as well as the arbitrarily defined deeper laminae 3.5 days after surgery. Although microglial cell numbers in laminae I were within normal range 35 days after axotomy, those of the more ventrally located laminae remained significantly greater than control values for the duration of the experimental period. These findings demonstrate that: 1) microglial cell proliferation in the dorsal horn is an early event in the central changes that are attendant to peripheral nerve injury 2) the time course of the response varies in cytoarchitecturally different regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00279661
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  • 30
    Electronic Resource
    Electronic Resource
    Hypertension and nephrotoxic lesions in rats 1 year after prenatal exposure to gentamicin (1988)
    Springer
    Archives of toxicology 62 (1988), S. 274-284 
    Details
    ISSN: 1432-0738
    Keywords: Gentamicin ; Postnatal development ; Blood pressure ; Embryotoxicity ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using the aminoglycoside antibiotic gentamicin persistant functional and morphological changes were induced prenatally in the rat kidney. After 6 days of s.c. treatment (110 mg gentamicin/kg body wt) from day 10 to 15 of pregnancy complete resorption was noticed in 8 of the 14 treated animals. Fifty-three newborn were obtained from six dams. One year later only 26 rats (16 male, 10 female) were still alive. The systolic arterial pressure of the female offspring was significantly increased (139±15 mm Hg versus 112±9 mmHg) compared with controls. No statistically significant effect could be noticed in the male offspring (128±5 mm Hg versus 118±21 mm Hg). Corresponding results were obtained from analysis of urea plasma concentrations. Another cohort of pregnant rats received daily injections of gentamicin from day 15 to 20 of pregnancy (110 mg/kg body wt s.c.). In this group 59 newborn from a total of 109 died within the first 5 days after birth. Six litters were observed postnatally. One year after birth the following blood pressure values were determined: 122±4 mm Hg (male) and 132±17 mm Hg (female). Urea plasma concentrations were significantly higher in female, but not in male, offspring. Light and electron microscopic inspection revealed pathological changes in the kidneys of the female offspring only. The degree of maternal kidney damage — which shows considerable variations — was monitored during the treatment period. For this purpose the plasma gentamicin and urea concentrations were measured on 3 days of treatment in all of the pregnant animals. The postnatal data (mortality, blood pressure, and urea plasma concentrations) show a correlation to the degree of maternal kidney impairment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00332487
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  • 31
    Electronic Resource
    Electronic Resource
    Adult-onset rod disease with abundant intranuclear rods (1988)
    Springer
    Journal of neurology 235 (1988), S. 343-347 
    Details
    ISSN: 1432-1459
    Keywords: Adult-onset rod disease ; Nemaline myopathy ; α-Actinin ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The third case of adult-onset rod disease (nemaline myopathy) with abundant myofibrillar as well as intranuclear rods is described. The 61-year-old woman suffered from progressive weakness of proximal extremities and of the neck, mimicking polymyositis. Muscle biopsy revealed a striking myopathic pattern, with intranuclear rods occurring in 31% of the fibres. On light and electron microscopy and by immunohistochemical study, the rods differed from myofibrillar rods. The absence of α-actinin in intranuclear rods suggests an enhanced readiness of actin filaments to bind to diverse proteins, instead of overproduction of α-actinin as the pathogenetic basis of the rod formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314229
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  • 32
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of two key enzymes of the 2-hydroxyglutarate pathway of glutamate fermentation in Acidaminococcus fermentans (1988)
    Springer
    Archives of microbiology 150 (1988), S. 504-508 
    Details
    ISSN: 1432-072X
    Keywords: Acidaminococcus fermentans ; Glutamate fermentation ; Electron microscopy ; Immunocytochemistry ; Post-embedding labelling ; Antibody-gold complexes ; Protein A-gold complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have investigated the in situ location of glutaconyl-CoA decarboxylase and 2-htdroxyglutaryl-CoA dehydratase in Acidaminococcus fermentans using the antibody-gold and protein A-gold techniques carried out as a post-embedding immunoelectron microscopic procedure. Polyclonal antisera were raised in rabbits against homogeneous fractions of the enzymes. Anaerobically grown cells of A. fermentans of the late exponential growth phase were fixed with 0.2% glutaraldehyde and 0.3% formaldehyde (final concentrations) in the growth medium. Dehydration of the cells was achieved with methanol. The cells were embedded in the low temperature embedding resin Lowicryl K4M. The markers indicative for antigenic sites of the two enzymes unequivocally demonstrate that the sodium pump glutaconyl-CoA decarboxylase is located at the cell periphery being a membrane-bound enzyme as expected whereas 2-hydroxyglutaryl-CoA dehydratase is a soluble cytoplasmic enzyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00422295
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  • 33
    Electronic Resource
    Electronic Resource
    The production and utilization of intermediary elemental sulfur during the oxidation of reduced sulfur compounds by Thiobacillus ferrooxidans (1988)
    Springer
    Archives of microbiology 150 (1988), S. 574-579 
    Details
    ISSN: 1432-072X
    Keywords: Thiobacillus ferrooxidans ; Sulfur production ; Sulfur oxidation ; Inhibitors ; Uncouplers ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The intermediary production of elemental sulfur during the microbial oxidation of reduced sulfur compounds has frequently been reported. Thiobacillus ferrooxidans, an acidophilic chemolithoautotroph, was found to produce an insoluble sulfur compound, primarily elemental sulfur, during the oxidation of thiosulfate, trithionate, tetrathionate and sulfide. This was confirmed by light and electron microscopy. Sulfur was produced from sulfide by an oxidative step, while the production from tetrathionate was initiated by a hydrolytic step, probably followed by a series of chemical reactions. The oxidation of intermediary sulfur was severely inhibited by sulfhydryl-binding reagents such as N-ethylmaleimide, by the addition of uncouplers or after freezing and thawing of the cells, which probably damaged the cell membrane. The mechanisms behind these inhibitions have not yet been clarified. Finally, it was observed that elemental sulfur oxidation by whole cells depended on the medium composition. The absence of sulfate or selenate reduced the sulfur oxidation rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408252
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  • 34
    Electronic Resource
    Electronic Resource
    Structure of the mitochondrial genome of Beta vulgaris L. (1988)
    Springer
    Theoretical and applied genetics 76 (1988), S. 753-759 
    Details
    ISSN: 1432-2242
    Keywords: Plant mitochondrial genome ; Minicircle DNA ; Electron microscopy ; Beta vulgaris L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The structure of mitochondrial DNA (mt-DNA) from sugarbeet (Beta vulgaris L.) has been studied by biochemical methods and electron microscopy. It was found to be complex multipartite consisting of two main classes of molecules: high molecules weight (HMW) mtDNA and low molecular weight (LMW) mtDNA. The HMW mtDNA consists of rosette-like structures and globules resembling chromomeres (150–200nm). A typical rosette has a protein core and radially stemming closed DNA loops (from 0.6-1.5 μm). The number of loops in a rosette varies from 16–30. The bulk of HMW mtDNAs are represented by interconnected rosettes (total contour length about 130–160 μm, 403–496 kbp). Such large circular DNAs may be evidence of the master chromosome arrangement of the sugarbeet genome. Globules and rosettes are interconnected by thick and thin DNA fibrils, along which nucleosome- and nucleomere-like structures are distributed. The LWM mtDNA is composed of two groups of supercoiled circular molecules, 0,2–1.5 μm and 0.02–0.05 μm in size. Electrophoretic analysis demonstrated that LWM mtDNA is represented by minicircle plasmid-like DNA molecules of 1.3, 1.4 and 1.6 kbp.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00303522
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  • 35
    Electronic Resource
    Electronic Resource
    Distribution of mitochondrial plasmid-like DNA in cultivated rice (Oryza sativa L.) and its relationship with varietal groups (1988)
    Springer
    Theoretical and applied genetics 76 (1988), S. 809-814 
    Details
    ISSN: 1432-2242
    Keywords: Electron microscopy ; Genetic variation ; Mitochondrial DNA ; Oryza sativa L. ; Plasmid-like DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitochondrial (mt) plasmid-like DNA was found in most of more than 100 rice cultivars (Oryza sativa L.) by the use of 0.7% agarose gel electrophoresis (AGE). The DNA varied in molecular weight and number. By electron microscopy, small circular DNAs of different sizes could be detected in addition to the DNAs of high molecular weight, even in cultivars in which mt plasmid-like DNA was not detected by AGE. The detection of the mt plasmid-like DNAs by AGE did not depend on their presence or absence, but on their high stoichiometry. The relationship between cytoplasms with mt plasmid-like DNAs and varietal (for example, Indica rice) groups was close. The geographical distribution of cytoplasms is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00273665
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  • 36
    Electronic Resource
    Electronic Resource
    Localization of 28 kDa calbindin in human odontoblasts (1988)
    Springer
    Cell & tissue research 254 (1988), S. 341-346 
    Details
    ISSN: 1432-0878
    Keywords: Odontoblast ; Calbindin ; Immunohistochemistry ; Electron microscopy ; Teeth ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence of 28 kDa calbindin in human odontoblasts was studied by use of specific antibodies raised against chick duodenal 28 kDa calbindin, in immunofluorescence, immuno-peroxidase, and electron-microscopic labelling experiments. The calbindin-like protein was detected mainly in the cytoplasm of odontoblast cell bodies, in their processes and occasionally in their nuclei. Correspondingly, at the ultrastructural level, immunoreactive material was associated with the cytosol, microfilaments and cilia. These findings suggest that human odontoblasts express a 28 kDa vitamin D-dependent calcium-binding protein, unlike those of rats and mice in which ameloblasts are the only cells immunoreactive for the protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225806
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  • 37
    Electronic Resource
    Electronic Resource
    Development of follicular dendritic cells in lymph nodes of B-cell-depleted mice (1988)
    Springer
    Cell & tissue research 254 (1988), S. 449-454 
    Details
    ISSN: 1432-0878
    Keywords: Follicular dendritic cells ; Lymph nodes ; Electron microscopy ; Nude mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We have studied follicular dendritic cells (FDC) in lymph nodes of normal and thymus dysgeneic nude mice depleted of B-cells by chronic treatment with anti-IgM antibodies. We found that B cell depletion was accompanied by the absence of mature FDC as defined morphologically at the ultrastructural level. Only precursor FDC (p-FDC) could be demonstrated. Upon release of B-cell suppression, the repopulation of lymph nodes with B-cells was associated with the reappearance of fully differentiated FDC in primary follicles of nude mice and in secondary follicles of T-cell competent mice. We conclude that mature B-cells and/or B-cell products are required for the development of mature follicular dendritic cells in the mouse lymph node.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225818
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    Orthogonal arrays of particles in non-pigmented cells of rat ciliary epithelium: Relation to distribution of filipin- and digitonin-induced alterations of the basolateral membrane (1988)
    Springer
    Cell & tissue research 252 (1988), S. 165-173 
    Details
    ISSN: 1432-0878
    Keywords: Ciliary epithelium ; Orthogonal arrays of particles ; Filipin ; Freeze-fracture ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It has been suggested that orthogonal arrays of particles may increase the rigidity of plasma membrane, as does cholesterol. Therefore, using freeze-fractured non- pigmented ciliary epithelium, the distribution of such arrays was compared to the distribution of membrane deformations induced by the sterol-probes filipin and digitonin in different domains of the basolateral plasma membrane. The distribution of orthogonal arrays of particles was homogeneous between different regions of the basolateral membrane of the non-pigmented ciliary epithelium, while the number of filipin-induced alterations was nearly 4 times higher in the membrane domains not in contact with the basal lamina than in domains in contact with it. Contrary to the homogeneous distribution of arrays, digitonin-induced deformations also differed markedly in these two basolateral membrane domains. Considering that a marked positive response to sterol probes implies a high sterol content, we conclude that orthogonal arrays of particles can occur in plasma membrane regions well-provided with cholesterol and not in direct contact with the basal lamina. Other possible roles of these arrays are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213838
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  • 39
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of immunolabeled substance P and methionine-enkephalin-octapeptide in the surface layer of the dorsal horn of rat spinal cord (1988)
    Springer
    Cell & tissue research 253 (1988), S. 55-60 
    Details
    ISSN: 1432-0878
    Keywords: Substance P ; Enkephalin ; Spinal dorsal horn ; Immunocytochemistry ; Electron microscopy ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A preembedding dual immunolabeling technique and electron microscopy were utilized to demonstrate the localization of immunoreactive substance P and methionine-enkephalin-octapeptide (Enk-8) in ultrathin sections of the surface layer (laminae I and II) of rat spinal dorsal horn. The immunoreaction of Enk-8 was visualized as goldtoned silver particles and that of substance P as diaminobenzidine reaction products. Axonal terminals with immunoreactive substance P, and also unlabeled axonal terminals, formed synaptic junctions with the perikarya and dendritic processes of Enk-8-containing neurons. Dendritic profiles immunolabeled for substance P were synaptically linked with unlabeled axons but not with Enk-8-positive ones. Furthermore, it was found that Enk-8 axons and substance P axons terminated synaptically in juxtaposition to one another on the same immunonegative dendrites. Among the Enk-8-containing neurons axonal profiles also appeared to be synaptically associated with immunoreactive Enk-8 dendritic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221739
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  • 40
    Electronic Resource
    Electronic Resource
    Light- and electron-microscopic immunocytochemistry of peptidergic neurons innervating thoracico-abdominal neurohaemal areas in the blowfly (1988)
    Springer
    Cell & tissue research 253 (1988), S. 583-595 
    Details
    ISSN: 1432-0878
    Keywords: Bioactive peptides ; Coexistence of peptides ; Immunocytochemistry ; Electron microscopy ; Insect nervous system ; Calliphora erythrocephala, C. vomitoria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ventral thoracic neurosecretory cells (VTNCs) of the blowflies, Calliphora erythrocephala and C. vomitoria, innervating thoracic neuropil and the dorsal neural sheath of the thoracico-abdominal ganglion have been shown to be immunoreactive to a variety of mammalian peptide antisera. In the neural sheath the VTNC terminals form an extensive neurohaemal network that is especially dense over the abdominal ganglia. The same areas are invaded by separate, ut overlapping serotonin-immunoreactive (5-HT-IR) projections derived from neuronal cell bodies in the suboesophageal ganglion. Immunocytochemical studies with different antisera, applied to adjacent sections at the lightmicroscopic level, combined with extensive cross-absorption tests, suggest that the perikarya of the VTNCs contain co-localized peptides related to gastrin/cholecystokinin (CCK), bovine pancreatic polypeptide (PP), Met- and Leuenkephalin and Met-enk-Arg6-Phe7 (Met-enk-RF). Electron-microscopic immunogold-labeling shows that some of the terminals in the dorsal sheath react with several of the individual peptide antisera, whilst others with similar cytology are non-immunoreactive. In the same region, separate terminals with different cytological characteristics contain 5-HT-IR. Both 5-HT-IR and peptidergic terminals are localized outside the cellular perineurium beneath the acellular permeable sheath adjacent to the haemocoel. Hence, we propose that various bioactive substances may be released from thoracic neurosecretory neurons into the circulating haemolymph to act on peripheral targets. The same neurons may also interact by synaptic or modulatory action in the CNS in different neuropil regions of the thoracic ganglion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219749
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    The efferent innervation of the genital chamber by an identified serotonergic neuron in the female cricket Acheta domestica (1988)
    Springer
    Cell & tissue research 252 (1988), S. 449-457 
    Details
    ISSN: 1432-0878
    Keywords: Serotonin (5-HT) ; Genital chamber ; Immuno-cytochemistry ; Electron microscopy ; Cricket, Acheta domestica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The serotonergic innervation of the genital chamber of the female cricket, Acheta domestica, has been investigated applying anti-serotonin (5-HT) immunocyto-chemistry at both light- and electron-microscopic levels as well as using conventional electron microscopy. Whole mount and pre-embedding chopper techniques of immuno-cytochemistry reveal a dense 5-HT-immunoreactive network of varicose fibers in the musculature of the genital chamber. All of these immunoreactive fibers originate from the efferent serotonergic neuron projecting through the nerve 8v to the genital chamber (Hustert and Topel 1986; Elekes et al. 1987). At the electron-microscopic level, 5-HT-immunoreactive nerve terminals, which contain small (50–60 nm) and large (∼ 100 nm) agranular vesicles as well as granular vesicles (∼100nm), contact the muscle fibers or the sarcoplasmic processes without establishing specialized neuromuscular connections. In addition to the 5-HT-immunoreactive axons, two types of immunonegative axons can also be found in the musculature. By use of conventional electron microscopy, three ultrastructurally distinct types of axon processes can be observed, one of which resembles 5-HT-immunoreactive axons. While the majority of the varicosities do not synapse on the muscle fibers, terminals containing small (50–60 nm) agranular vesicles occasionally form specialized neuromuscular contacts. It is suggested that the 5-HTergic innervation plays a non-synaptic modulatory role in the regulation circular musculature in the genital chamber of the cricket, while the musculature as a whole may be influenced by both synaptic and modulatory mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214388
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  • 42
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    Electronic Resource
    Atrial-specific granules in the hearts of normal and water-deprived rats (1988)
    Springer
    Cell & tissue research 253 (1988), S. 547-552 
    Details
    ISSN: 1432-0878
    Keywords: Atrial-specific granule ; Atrial natriuretic polypeptide ; Water deprivation ; Immunohistochemistry ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of atrial-specific granules, which contain atrial natriuretic polypeptide (ANP), was studied in the cardiac tissue of untreated controls and water-deprived rats by means of conventional and immunoelectron microscopy. Immature secretory vesicles or granules appeared to become buded off from the Golgi cisternae and then fused to form specific A-granules. An electron-dense plate with a fuzzy coat was frequently found on the limiting membrane at the end of such fusion. Pale specific B-granules, which were less electron-dense, larger, and more granular than A-granules, were found in small numbers in the left atrial cardiocytes, but rarely in the right ones. Very pale granules with a less granular matrix, considered to be B-type granules which had lost their electron-density, and which had less immunoreactivity for ANP, were numerous in the cardiac tissue after water deprivation. This morphological change, which is interpreted as an indication of granule degradation, was in agreement with the noted increase of natriuretic activity in the atrial tissue of water-deprived specimens.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219745
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    Epidermal growth factor (EGF)-induced morphological changes in the basement membrane of chick embryonic skin (1988)
    Springer
    Cell & tissue research 254 (1988), S. 481-485 
    Details
    ISSN: 1432-0878
    Keywords: Embryonic skin ; Epidermal growth factor ; Basement membrane ; Electron microscopy ; Chick
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of epidermal growth factor (EGF) on the basement membrane structure of chick embryonic skin cultured in a chemically defined medium (BGJb) containing 20 mM hydrocortisone, and EGF at 10, 50, or 100 ng/ml supplemented with 5% delipidized fetal calf serum, was examined by electron microscopy. During development of the epidermis in vitro, EGF (100 ng/ml) caused striking changes to occur in the basement membrane structure and in the keratinization process. The basement membrane frequently became discontinuous with many gaps apparent in section, and occasionally became folded following detachment from the basal surface of the epidermis and protruded into the underlying dermis. In the basal and intermediate cells of EGF-treated epidermis, tonofilament bundles were decreased in number, while desmosomes and hemidesmosomes revealed no significant changes in morphology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226497
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    Electronic Resource
    Unifying principles in intermediate filament (IF) structure and assembly (1988)
    Springer
    Protoplasma 145 (1988), S. 73-81 
    Details
    ISSN: 1615-6102
    Keywords: Intermediate filament structure ; Intermediate filament assembly ; Desmin ; Keratins ; Neurofilaments ; Nuclear lamins ; Cytoskeleton ; Electron microscopy ; Polymerization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01349341
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  • 45
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    Evaluation of 111In labelled white blood cells by in vitro functional tests and electron microscopy (1988)
    Springer
    European journal of nuclear medicine 14 (1988), S. 159-164 
    Details
    ISSN: 1619-7089
    Keywords: 111In-white blood cells ; Chemotaxis ; Phagocytosis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have studied the influence of granulocyte labelling with commercially available 111In-oxine, tropolone (trop) or home made 111In-Mercapto pyridine (Merc) prepared by the method of Thakur (1985) on the cell structure by electron microscopy and on the cell function by enzymatic tests, random migration, chemotaxis, phagocytosis and bactericidal activity. The granulocytes were labelled with 400 μCi 111In-oxine in saline or 111In-trop or Merc in plasma. The effect of the chelating agents with and without addition of the tracer was studied (n=4) with varying concentrations: 5–10 μg/ml oxine, 10–160 μg/ml trop and 1–4 μg/ml Merc. Chemotaxis and random migration were not affected by 111In-trop and clearly supressed by 111In-oxine and Merc; the other tests were normal. The cell structure was disturbed by Merc. The labelling efficiency was excellent with oxine (90%), acceptable with trop (30%–80%) and poor with Merc (10%–25%). Without 111In, chemotaxis and random migration were normal up to a concentration of 80 μg/ml trop, 8.5 μg/ml oxine and 1 μg/ml Merc. With addition of 111In, chemotaxis and random migration were unaffected up to 80 gmg/ml by trop and markedly supressed by Merc and oxine. It is concluded that labelling with 111In-trop assures intact cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293542
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    The barrier-like role of activated connective tissue against the spread of supraglottic laryngeal carcinoma (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 151-154 
    Details
    ISSN: 1434-4726
    Keywords: Supraglottic carcinoma ; Light microscopy ; Electron microscopy ; Activated connective tissue barrier
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light microscopic investigations of whole organ serial sections of 15 laryngectomy specimens with supraglottic carcinomas and comparative electron microscopic studies of the upper and lower poles of the tumors were carried out. The ultrastructure of different poles of the same supraglottic tumors was investigated and showed a more progressive fibrillogenesis with an activation of the connective tissue elements of the border on the lower pole of the malignancy. A significant role is attributed to the barrierforming feature of activated connective tissue with respect to the inhibition of the extension of tumor into the glottic region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464017
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    Ultrastructural localization of Ca2+-binding sites in the spiral limbus, the stria vascularis and Reissner's membrane of the guinea pig (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 279-283 
    Details
    ISSN: 1434-4726
    Keywords: Calcium ; Reissner's membrane ; Stria vascularis ; Limbus ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cations were precipitated with potassium antimonate in the cochlea of the guinea pig and electron microscopy was used to analyze the distribution of the formed reaction products. Differences in precipitate density between neighboring cells in Reissner's membrane, in the stria vascularis and in the limbus are described. Electron spectroscopic imaging was performed to obtain information about the spatial distribution of the precipitates and their elemental composition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464630
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    Masthead (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988) 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250101
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    Error estimation and adaptivity in flow formulation for forming problems (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 23-42 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A very simple and reliable error estimator has recently been developed for problems of linear elasticity.1 This leads naturally toa predication of an h-mesh refinement required for a given accuracy and with a suitable mesh generator2 for an efficient adaptive process. In this paper we extend the methodology developed previously to incompresible plastic flow of metals or polymers using the ‘flow formulation’ approach.3The examples of application include steady state extrusion problems for which exact solutions are available and hence allow the efficiency of the error estimates to be tested as well as more complex problems of upsetting in which the mesh is updated. It is found that the estimator performs well under various circumstances and provides an economical adaptive process.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250105
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  • 50
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    Ignition phase transition of a polymer: Convective exposure (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 373-386 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The ignition of a semi-infinite solid polymer under convective exposure is investigated. A quasi-steady approximation is used for the gas phase and the transient effect is accounted for in the solid phase only. Both surface and gas phase chemical reactions are included simultaneously. The ignition mechanism is studied in terms of the concurrent heat transfer, mass transfer, mass transfer and chemical processes at the surface as well as in the gas phase. The gas phase governing equations are integrated independently from the solid phase energy equation using the Adams-Moulton subroutine. Corrections to the iterative procedure are carried out by establishing a set of perturbation equations and using the Newton-Raphson and least-squares methods. The results indicate that ignition occurs in the heterogeneous mode within a narrow range of low flow velocities and high temperatures. An ignition phase transition point exists, and within a wide range of high flow velocities, ignition switches to the homogeneous mode.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250208
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    Shape design sensitivity analysis for non-linear anisotropic heat conducting solids and shape optimization by the BEM (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 109-120 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Shape design sensitivity analysis (SDSA) expressions have been derived for non-linear anisotropic heat conducting solid bodies by following the material derivative concept and adjoint variable method of optimal shape design given in the literature. The variation of a general integral functional has been described in terms of primary and adjoint quantities evaluated at the varying boundaries. As an example problem in shape optimization, optimal outer boundary profiles of an orthotropic solid body are obtained by the boundary element method (BEM), after reformulating the SDSA equations in a form which is most suitable for the BEM.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260108
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  • 52
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    Analyses of steady-state visco-elastic fluids using the penalty function method (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 43-54 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The application of the penalty-function formulation of the finite element method is made possible for analysing visco-elastic fluid flows by the method which decouples the momentum and continuity equations from the constitutive equation. An upwind finite element scheme is combined with the method in order to solve the constitutive equation. As visco-elastic fluid models, Jaumann derivative, upper and lower convected derivatives are considered. The Poiseuille flow and the flow through a plane converging channel are analysed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250106
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    Approximate methods for analysing the cold drawing of polymeric fibres and films (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 99-112 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Approximate methods for analysing steady-state cold drawing processes in polymer forming are discussed. These methods are applied to both axisymmetric and plane-strain drawing. The cold drawing process is associated with steady-state neck propagation along the specimen. Modifications are introduced in the approximate steady-state analysis which reflect the neck initiation and localization phases prior to steady-state drawing. This is accomplished without resorting to an analysis of the entire load-deformation history of the process. Finite element results are also presented and compared with those of the proposed approximate analyses. These comparisons show the approximate analysis to be an extremely efficient and quite accurate computational scheme for the analysis of steady-state cold drawing processes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250110
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    Analysis of stress and strain distributions in slab rolling using an elastic-plastic finite-element method (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 55-66 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The cold rolling of rectangular section slabs is analysed for a range of width-to-height ratios (one to three) for which spread of the workpiece is appreciable. This necessitates the use of a three-dimensional model. An elastic-plastic finite-element method is used to provide a complete description of the slab rolling process.The pressure distribution at the workpiece/roll interface is found to show the typical ‘friction-hill’ observed in near-plane-strain experiments, but the pressure varies across the width of the interface. The shear-stress distribution at the roll interface provides detailed information about the ‘neutral line’ which is usually assumed to occur where the shear stress changes direction. The 3-D analysis shows clearly that there is a flow divide in both longitudinal and transverse directions.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250107
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    Numerical simulation of the densification behaviour of metal powder during hot isostatic pressing (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 213-225 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A numerical method is introduced which is based on metal flow theory and simulates the densification of metal powder during hot isostatic pressing.The method, in which nodal velocities are variables, takes into consideration the dependence of flow stress on the temperature, strain rate and relative density of the material. The compressibility of porous metal as well as the incompressibility of fully dense metal are also taken into account.Porous specimens of the superalloy MERL76 were subjected to uniaxial compression tests at high temperature in order to determine the parameters of the equations on which the method is based. The densification behaviour of a turbine disk and two cylindrical components was numerically simulated and compared with experimental results.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250117
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    Preface (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. i 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250202
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  • 57
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    Coarse-fine mesh method for heat and mass transfer in locally complex flows (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 347-355 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Combined forced and free convective flows having locally complicated geometries or boundary conditions were numerically studied with a finite difference method of coarse and fine meshes. The coarse-and-fine mesh method developed can be used for numerical calculations of both unsteady and steady processes of heat and mass transfer in convective and diffusion flows which are strongly influenced by locally fine flows. The method was applied to a numerical calculation of the steady flow field of a CVD (chemical vapour deposition) reactor which has locally complicated flows caused by small inlet nozzles. The results of the calculation showed a considerable contribution of locally fine flows to the overall flow field, which is well predicted with the present method.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250206
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  • 58
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    Thermal analysis of human body-clothing-environment system (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 357-371 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: For the solution of thermal comfort problems a coupled model is presented consisting of the thermal model of the human body and of the clothing, with boundary conditions of the third kind.For thermal modelling the human body is divided into 16 parts according to the special character of the internal heat generation, of the blood vessel system and of the sweat secretion mechanism. Part models are connected by the flow paths of arteries and veins.Transport phenomena in the clothing are treated by a coupled heat and mass transfer model which permits various kinds of clothing for the different parts of the body.The equation system of the full model has been solved numerically by using time stepping schemes. As the results of the computations an approximative temperature field of the human body is produced.Calculated results have been compared with Experimental data.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250207
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  • 59
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    Finite element simulation of hot isostatic pressing of metal powders (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 191-212 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Rate form constitutive equations of elasto-viscoplastic type are expressed in a manner similar to that of classical metals, but the viscoplastic part, which is no longer incompressible, is related to the rate of variation of porosity. An incremental and implicit algorithm has been implemented in a finite element program in order to simulate hot isostatic pressing of an Astroloy powder. Temperature distributions are shown to induce strong density variations in real parts during hot isostatic pressing (HIP). For one particular turbine disk, we tested the sensitivity of the final shape to different processing parameters. Computed final shapes compare well with experimental ones.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250116
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    Analysis of bending effects in sheet forming operations (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 253-267 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The majority of work in numerical analyses of sheet metal forming operations is based on the simple membrane-shell theory which neglects the effect of sheet bending. While useful information can be extracted from these analyses, especially for stretch-dominated operations, the membrane theory is basically inadequate for analysing the draw-type operations where sheet metal bends, slides and unbends over a draw radius.This paper presents axisymmetric and plane-strain finite element analyses of stretch/draw of sheet metal over a die corner radius. Numerical solutions obtained from a total Lagrangian formulation of a finite-strain thin shell theory are used to indicate the relative significance of including the bending effects in various simple forming operations. Comparisons of the calculated results with available experimental data are also given.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620250119
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    A finite element simulation of the sheet metal forming process (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 283-292 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element simulation code of the sheet metal forming process has been developed. This simulation code plays an important role in the computer aided engineering (CAE) system for an automobile parts forming process, which includes the pre- and post-processes. The paper presents the development of an updated Lagrangian type finite element modelling, based on the elastic-plastic (J2 flow law) membrane shell theory. An attempt is made to calculate the strain distribution incurred by peripherally clamped or non-clamped square plates when impressed by rigid punches. These are the cases of square box-shape punch drawing and arbitrary shaped panel stretch forming.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250121
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    Punch stretching of sheet metal and differential equations on manifolds (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 269-282 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The goal of mathematical modelling of sheet metal forming processes is to provide predictive tools for use in the design of stamping processes and the selection of sheet materials. Most current approaches to finite element modelling of large deformation, elastic-plastic sheet metal forming problems use a rate form of the virtual work (equilibrium) equations, and a single-field finite element representation of the displacement components. Called the incremental method, this approach does not produce approximations which satisfy the discrete equilibrium equations at all times, and consequently it demands small time steps to insure stability and numerical accuracy. This paper describes a variant of the mixed method in which displacements, stresses, effective strain and pressures are all given separate finite element representations. The equilibrium equations in non-rate form are discretized to produce a system of algebraic equations which are coupled with the constitutive equations and then integrated using state-of-the-art numerical software. When used to model rate sensitive sheet materials in hydrostatic bulging, plane strain punch stretching and hemispherical punch stretching, the new approach proved to be between 6 and 26 times as fast as the old incremental method.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620250120
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    Buoyant flow calculations with non-orthogonal curvilinear co-ordinates for vertical and horizontal parallelepiped enclosures (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 331-345 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A control-volume-based finite-difference formulation is developed for heat transfer and fluid flow in arbitrary three-dimensional parallelepiped enclosures. The governing equations in Cartesian co-ordinates are first transformed to those in non-orthogonal curvilinear co-ordinates by tensor transformations. After introducing the properties of the parallelepiped geometry, equations are obtained in the primitive variables for which all vectors and tensors are based on the curvilinear co-ordinates. With proper treatment of the heat flux and stress tensor terms, the finite-difference equations, analogous to those in the Cartesian coordinates, are formed. Examples are utilized to show the validity of the methodology and the results are found to compare well with existing experimental data. The differences in heat transfer and fluid flow inside parallelepiped enclosures and rectangular enclosures are delineated and discussed from a physical point of view.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620250205
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    Finite element analysis of turbulent forced convection in lid-driven rectangular cavities (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 313-329 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Turbulent fluid flow and heat transfer in lid-driven rectangular cavities are analysed by a finite element procedure for the prediction of the turbulent forced convection in two-dimensional recirculating flows. The (k-ε) model is used to compute effective viscosities and thermal conductivities. The fluid flow and turbulence model parabolic equations are solved sequentially, one after the other. Then, the calculated velocity distribution is used in the solution of the steady state energy equation to yield the temperature field. Aspect ratios e=0·75, 1·0 and 1·5 and Reynolds numbers ranging from 5 × 104 to 4 × 105 are considered in the numerical examples.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620250204
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    Non-linear simulation of dendritic solidification of an undercooled melt (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 415-444 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Two-dimensional finite element simulations of solidification for quiescent undercooled pure metals are presented. The full non-linear, transient heat equation is used with phase front tracking which is subject to local curvature and interfacial kinetics. During early stages of the waveform instability the simulated solutions match the linear stability analysis with fidelity. Beyond the valid range of that analysis the numerical solution continues to demonstrate the physically observed exponential growth behaviour and characteristic spacing between fingers. Whereas the simulations show the sensitivity of dendritic growth to initial conditions, as expected for an unstable process, the overall pattern formation preserves the characteristic spacing. The simulations are terminated after the onset of bifurcation. Thereafter, the numerical model is inappropriate for physical comparison owing to the planar, two-dimensional limitation.
    Additional Material: 24 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620250211
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    A regular indirect boundary element method for thermal analysis (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 25 (1988), S. 495-515 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A Regular Indirect Boundary Element formulation is developed following a weighted residual approach. In this formulation, the fictitious source density, which appears in the integral equations of the method, is distributed on a surface which is exteriorly separated from the physical field boundary of the problem. This approach does not require the evaluation of singular integrals and produces undeteriorated solutions at geometric discontinuities. The formulation is presented here as applied to two dimensional and axisymmetric thermal problems. It includes a different subregioning scheme which treats each subregion, of a multidomain problem, separately, thereby eliminating the need for a sophisticated reduction scheme.
    Additional Material: 24 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620250214
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    Warping torsion in thin-walled open section beams using the semiloof beam element (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 231-243 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Many structural members including metallic, reinforced polymer and concrete members must be modelled, in the simplest approximation, as thin-walled beams whose cross-sections exhibit significant, out-of-plane warping owing to torsion. The elastic capabilities of the semiloof beam element are extended to include warping torsion of thin-walled open section beams. The performance of the extended element is compared with that of the original formulation.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260116
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    Partial eigensolution of damped structures by non-linear optimization (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 143-152 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The partial solution of damped structures involves the determination of only a few of the resonant frequencies and corresponding damping characteristics and mode shapes. The procedure outlined here uses a modification of the variable metric solution algorithm, in which the dicision variables are elements of the complex eigenvector and the eigenvalue. The quadratic eigenvalue problem is reformulated as a sequential unconstrained minimization problem. Both normality and orthogonality constraints are incorporated in the objective function. The method is compared to an adaptation of the subspace iteration technique, also applicable to the quadratic eigenvalue problem.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/nme.1620260110
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    An element-by-element method for heat conduction CAE including composite problems (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 199-215 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Mechanical computer aided engineering (CAE) implies large finite element problems due to the geometric complexity of the ‘true’ 3D designs. Application of the standard finite element technique is not practical for such problems because the direct solution of the global matrix equations is too costly. This paper considers the element-by-element implicit algorithm for the CAE application of transient heat conduction. The direct solution is avoided by an operator splitting or approximate factorization technique. This results in both the execution time and storage requirements for each time step being linearly proportional to the number of elements while retaining unconditional stability. However, the approximate factorization introduces additional truncation error and incorrect jump conditions at material interfaces. Detailed analyses and numerical experiments are carried out in one dimension to assess the nature and mechanism of these inaccuracies. A three dimensional implementation is then compared with one dimensional results. The need for an additional predictor-corrector element-by-element algorithm for 3D composite problems is also presented.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260114
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    Letters to the editor (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 281-282 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260119
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    Conference diary (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 291-292 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260124
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    Plastic design. An imposed hinge-rotation approach, P. Zeman and H. M. Irvine, Allen & Unwin, London, 1986, 86, pages (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 290-290 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260123
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    Finite elements and solution procedures for structural analysis. vol. I: Linear analysis. M. A. Crisfield, Pineridge Press, Swansea, 1986. No. of pages: 272 (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 289-289 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260122
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    Hybrid finite element-Monte Carlo method for coupled conduction and gas radiation enclosure heat transport (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 361-378 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A hybrid two-dimensional finite element-Monte Carlo numerical solution method has been developed for solving complex transient non-linear gas radiation enclosure problems. Solid conducting media are coupled to conducting gaseous or particulate participating media and both may be internally energy generating. Bilinear isoparametric elements are used, allowing geometrically complex enclosures with internal objects to be present. Radiative energy transport within the gaseous enclosures is accounted for using a Monte Carlo method which permits a broad range of complexities. Included here are: diffuse-grey and specularly reflecting walls with temperature and spectrally dependent, and non-homogeneous emissivities or absorptivities; absorbing/emitting gases with temperature and spectrally dependent, and non-homogeneous emissivities or absorptivities; and isotropic or anisotropic scattering gases or particles. This method was verified by solving several standard steady state problems and comparing the solutions to those found using the conventional finite element, the P-N and the exchange factor methods. Solution times are comparable to those of the finite element method. A more complex transient problem solution is then given to demonstrate the versatility and power of the method.
    Additional Material: 17 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260206
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    Derivatives of eigenvalues and eigenvectors of a general complex matrix (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 293-311 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A survey of methods for sensitivity analysis of the algebraic eigenvalue problem for non-Hermitian matrices is presented. In addition, a modification of one method based on a better normalizing condition is proposed. Methods are classified as Direct or Adjoint and are evaluated for efficiency. Operation counts are presented in terms of matrix size, number of design variables and number of eigenvalues and eigenvectors of interest. The effect of the sparsity of the matrix and its derivatives is also considered, and typical solution times are given. General guidelines are established for the selection of the most efficient method.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260202
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    Convergence of curved shell elements based on assumed covariant strain interpolations (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 329-347 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A C0 9-node shell element based on assumed interpolations of covariant strain components defined with respect to the element natural co-ordinate system has recently been proposed. In this formulation, the covariant strains are obtained directly from the Cartesian strains by tensor transformation without any need to compute laminar co-ordinate based strains. In the present work, the interpolated covariant strains used in this element are analysed to determine their satisfaction of the basic requirements for successful strain interpolation. These basic requirements are stated as invariance to rigid body motions and ability to represent constant and linear strain states. In the finite element formulation, the weak form of momentum balance is expressed in terms of covariant strains and contravariant stresses. The corresponding elasticity tensor is a function of the components of the metric tensor associated with the element natural co-ordinate system. The invariance properties of the metric tensor in the context of the finite element approximation are also discussed.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260204
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    Spline collocation in the flow of non-Newtonian fluids (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 413-421 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Natural convection flow of a non-Newtonian fluid between two vertical infinite parallel flat plates forms the case study of the present work. Velocity profiles for the Prandtl-Eyring and Powell-Eyring fluid models are obtained through the method of spline collocation.The applicability and reliability of the techniques employed here are discussed in detail with a suggested error estimate and analysis. Accuracy in the successive iterations in the results is of the fourth order. To maintain this accuracy the help of a computer is not required for carrying out the calculation of velocity profiles. Thus the simplicity of the spline collocation technique is demonstrated in its application to flow problems.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260209
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    Computation of hybrid element matrices by elimination techniques (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 423-435 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Three functionals, the modified forms of the Hu-Washizu, Hellinger-Reissner, and complementary energy principles, as developed by Pian, Chen, and Kang1.2 are stated. Finite element discretization of each is presented and the ensuing computations developed, resulting in the element stiffness matrix, with displacement degrees-of-freedom only, and the stress recovery matrices. Subroutines are presented for this purpose where the close relationship of the three principles is exploited to result in a compact hybrid element technique. The techniques herein reviewed are assumed applicable at the individual element level. The usual summation over all elements in the model is implied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260210
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    Accuracies of numerical solution methods for the pressure-modified von Mises modelThe paper was presented at Tenth U.S. National Congress of Applied Mechanics, June 16-20, 1986, Austin, Texas, U.S.A. (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 453-465 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The accuracy of three numerical algorithms - the tangent-stiffness radial-return, secant-stiffness radial-return and simple radial-return methods - is analysed against exact solutions for the pressure-modified von Mises yield criterion with the associated flow rule. The governing equations of the exact solutions are derived using a simple and innovative geometrical approach, in terms of a pair of non-linear, first order differential equations, in rate change of the deviatoric radius and in rate change of angular locations on the deviatoric plane. For both accuracy and efficiency, and for small and large time steps, the secant-stiffness radial-return method is the best of all.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260212
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    Three-dimensional elastic finite element study of the skid resistance of grooved pavement (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 437-452 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A three-dimensional finite element model has been developed to simulate the sliding of a rubber block over a grooved road surface. The model makes use of the symmetries of the problem to simplify the analysis, so that two-dimensional isoparametric elements of both rectangular and triangular configuration have been extended into the third dimension. A procedure for analysing the behaviour of any one groove to groove unit of the pavement is also developed, and this is extended so that the contact between the sliding rubber block and the leading edge of each raised pavement section is analysed. Preliminary comparisons between theoretical calculations and experimental measurements indicate that the finite element procedure provides an accurate and economical estimate of the behaviour of the rubber slider as it is pressed into a grooved pavement. Elastic predictions of sliding resistance seem reasonable at low sliding speeds, but viscoelastic rubber analysis appears necessary if higher speed skid resistance is to be predicted.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260211
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    Analysis of steady free convection from an axisymmetric heat-generating body embedded in a semi-infinite porous medium (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 467-487 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An analysis is presented for the steady state free convective flow and heat transfer from an axisymmetric heat-generating body that is embedded in a fluid-saturated, semi-infinite, porous medium. The porous medium is assumed to be rigid, homogeneous and isotropic, and be in thermal equilibrium with the fluid. The fluid is assumed to be incompressible, with the density changes contributing only towards the buoyancy forces via the Boussinesq approximation. The governing equations for the fluid consist of the equation of continuity, Darcy's law and the equation of energy. After introducing the stream function concept, the equations governing the stream function and pressure are derived. Using the non-dimensional variables, the non-dimensional equations governing the non-dimensional forms of the temperature, stream function and pressure are dervied and the appropriate boundary conditions are stated. The mathematical formulation contains two parameters; D, the non-dimensional depth of the body from the surface of the porous medium, and a product Raθs of Rayleigh number (Ra) and the non-dimensional surface temperature of the body (θs). The Galerkin finite element method, with linear, isoparametric, quadrilateral elements, is used to reduce the mathematical formulation into a set of algebraic equations. The expressions to calculate the non-dimensional surface temperature and Nusselt number of the body, and the non-dimensional velocity of the fluid, are derived. A computer code has been developed to solve the algebraic equations, using Gauss elimination procedure, in a banded matrix form. The computer code, in addition to the non-dimensional temperature, stream function and pressure, calculates the isothermal lines, non-dimensional surface temperature of the body, Nusselt number of the body, velocity field and isobars.To demonstrate the application of the code, a spherical heat-generating body is considered as an example. Numerical results are obtained for D = 3 and 6, and Raθs = 0.001, 0.1, 1 and 5, and presented.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/nme.1620260213
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    Masthead (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988) 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260301
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    Announcements (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 527-530 
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    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260217
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    An integrated approach to the synthesis of geometrically non-linear structures (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 555-570 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An integrated approach to the minimum weight design of geometrically non-linear three dimensional truss structures with geometric imperfections, subject to inequality constraints on static displacements, stresses, local buckling and cross sectional areas, is investigated. The integrated structural synthesis problem involves design and response quantities as independent variables and equilibrium equations, describing the finite element model, as equality constraints. The non-linear structural analysis and the optimization are thus merged together into a single process. A computer program developed to compute the contraint values and analytical gradients is coupled with a generalized reduced gradient algorithm to solve the integrated problem. Numerical results for a geometrically non-linear shallow dome example problem are presented for various types of imperfections. Furthermore, it is found that the algorithm is capable of detecting and guarding against system as well as element elastic instability using equilibrium information only, that is, without imposing system and local buckling inequality constraints.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260304
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    Theoretical basis of the finite element iterative method for the eigenvalue problem in stationary cracks (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 531-539 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: In a recently published paper a finite element based iterative method was introduced for the solution of the eigenvalue problem of stationary cracks.1 In this paper we give the theoretical basis of this iterative method and we show why it converges and how it could be extended to more complex fracture problems. The cases of cracks at interfaces are illustrated.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260302
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  • 86
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    Application of the finite element iterative method to the eigenvalue problem of a crack between dissimilar media (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 541-554 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The finite element iterative method is applied to the eigenvalue problem of a crack between dissimilar media. In this case the transfer matrix is non-symmetric, which leads to complex eigenvalues. The singularity obtained agrees with the analytical results of r(-1/2+ie). The method of evaluating the eigenfunctions is general and can be applied to more complex cases of material and geometry, which are frequently encountered in composite materials. A powerful method for evaluating stress intensities in dissimilar media is given in the Appendix. The method is also reduced for homogeneous media to give stress intensity factors for modes I, II and III.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260303
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  • 87
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    Elasto-plastic large deformation analysis of space-frames: A plastic-hinge and stress-based explicit derivation of tangent stiffnesses (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 589-615 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper deals with elasto-plastic large deformation analysis of space-frames. It is based on a complementary energy approach. A methodology is presented wherein: (i) each member of the frame, modelled as an initially straight space-beam, is sought to be represented by a single finite element, (ii) each member can undergo arbitrarily large rigid rotations, but only moderately large relative rotations; (iii) a plastic-hinge method, with arbitrary locations of the hinges along the beam, is used to account for plasticity, (iv) the non-linear bendin-stretching coupling is accounted for in each member, (v) the applied loading may be non-conservative and (vi) an explicit expression for the tangent stiffness matrix of each element is given under conditions (i) to (v). Several examples, with both quasi-static and dynamic loading, are given to illustrate the accuracy and efficiency of the approaches presented.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260306
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  • 88
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    Multi-grid solutions to the elastic plastic torsion problem in multiply connected domains (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 631-646 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The elastic plastic torsion problem for an elastic, perfectly plastic cylinder with multiply connected cross section twisted around its longitudinal axis is formulated as an obstacle problem for an associated stress potential, the obstacle being defined in terms of a generalized distance function. Based upon the reformulation of the obstacle problem as an equivalent linear complementarity problem, the latter is discretized by means of finite difference techniques, and a monotonically convergent iterative scheme for its numerical solution is developed. At each step of the iteration the solution of a reduced system of discrete Poisson equations is required which is done by applying multi-grid techniques with respect to a hierarchy of grid-point sets. Combined with a suitably chosen nested iteration process this results in a computationally very efficient algorithm for the approximate solution of the elastic plastic torsion problem.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260308
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  • 89
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    Application of spline strip method to analyse vibration of open cylindrical shells (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 663-676 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper deals with the vibration of open cylindrical shells by the spline strip method based on Novozhilov's shell theory. Convergence of the solutions is investigated in a few examples and is found to be satisfactory. The accuracy of the results is compared with those calculated by other numerical methods and found to be in good agreement.The effect of inlcuded angles and inplane constraints on vibrating characteristics of simply supported cylindrical shells is shown.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260310
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  • 90
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    A quadrilateral finite element including vertex rotations for plane elasticity analysis (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 717-730 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A finite element of arbitrary quadrilateral shape is presented for plane elasticity analysis. The element is derived from triangular fields of compatible quadratic displacements with vertex connectors which include rotations. All rigid body movements and constant strain states are recovered exactly. Results from several test problems demonstrate that very good numerical accuracy is obtained for both displacements and stresses, even for quite coarse finite element meshes.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260314
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  • 91
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    A numerical case study of a non-Newtonian flow problem (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 695-704 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper addresses some of the theoretical aspects involved in the numerical study of non-Newtonian flow problems. We consider the second-order Rivlin-Erickson constitutive model due to the simple differential form that emerges for the system of equations that govern the flow when expressed in stream function-vorticity variables. This model describes slightly elastic fluids that exhibit a constant viscosity behaviour. A steady two-dimensional flow is studied through a planar contraction geometry.An auxiliary variable is introduced into the problem formulation producing a non-linear system of differential equations comprising two elliptic equations and one hyperbolic equation. This system is discretized by finite difference methods and the resulting system of non-linear algebraic equations is solved iteratively by successive substitutions. The simple structure of this iteration permits a convergence analysis which is presented in Section 2. This analysis is performed prior to the spatial discretization and establishes the dependence of the iteration upon the material parameters. At the discrete linearized equation level a combination of inner iterations for elliptic equations and direct marching for the hyperbolic equation is used. The stability of the marching scheme is considered in Section 4.3 and a discussion on the results is given in Section 5.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260312
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  • 92
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    A nine node finite element for analysis of geometrically non-linear shells (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1945-1962 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A nine node finite element is presented for the analysis of thin shell structures undergoing large deflection. The finite element formulation is based on the concept of degenerate solid shell element and the Hellinger-Reissner principle with independent strain. Three versions of assumed independent strain are selected to suppress spurious kinematic modes. One version leads to a finite element model which is kinematically stable at element level while the other two give globally stable models. Numerical tests indicate that the finite element model which is stable at element level may reveal the locking effect in certain cases. However, the other two models are free of locking.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260905
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  • 93
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    Finite element approximations of singular parabolic problems (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1989-2007 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: An efficient implementation of finite element methods for free boundary parabolic problems in general two dimensional space domains is presented. The Stefan problem, the Hele-Shaw problem and the porous medium equation are included. Backward differences or linearization techniques are used for the time discretization of the problem. The performances of these schemes are discussed with several numerical tests.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260907
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  • 94
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    A new hybrid transfinite element computational methodology for applicability to conduction/convection/radiation heat transfer (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1087-1100 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: This paper describes new and recent advances in the development of a hybrid transfinite element computational methodology for applicability to conduction/convection/radiation heat transfer problems. The transfinite element methodology, while retaining the modelling versatility of contemporary finite element formulations, is based on application of transform techniques in conjunction with classical Galerkin schemes and is a hybrid approach. The purpose of this paper is to provide a viable hybrid computational methodology for applicability to general transient thermal analysis. Highlights and features of the methodology are described and developed via generalized formulations and applications to several test problems. The proposed transfinite element methodology successfully provides a viable computational approach and numerical test problems validate the proposed developments for conduction/convection/radiation thermal analysis.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260507
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  • 95
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    A robust triangular plate bending element of the Reissner-Mindlin type (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1169-1184 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A new triangular plate element is presented. This new element is based on independent interpolations for slopes, displacement and shear forces, and it is shown that it does not suffer from any defect common to other Mindlin plate elements. Several examples are presented to illustrate the behaviour of this new element.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260511
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    Computer analysis of structures matrix structural analysis, structured programming, Siegfried M. Holzer, Elsevier, 1985, pp. 426. ISBN 0-444-00943-4 (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1235-1236 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260515
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  • 97
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    Formulation and solution of hierarchical finite element equations (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1213-1233 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: The paper presents a general hierarchical formulation applicable to both elliptic and hyperbolic problems. Static and eigenvalue linear elastic problems as well as convection-diffusion problems are studied. The hierarchical formulation is well suited for adaptive procedures.For the convection-diffusion problem the hierarchical approximation is made in time only. Different hierarchical functions are proposed for different types of problems. Both weighted residual and least-squares formulations are applied. A combination of these two gives a penalty method with a constraint equation corresponding to the least-squares method. A whole class of time integration formulae is obtained. These are all suitable for adaptive procedures owing to the hierarchical approximation in the time domain. If a linear discontinuous hierarchical base function is used in the Galerkin weak formulation, the method so obtained corresponds to the discontinuous Galerkin method in time and is especially suited for convection dominated problems. The streamline-diffusion method is found to be the aforementioned penalty method.This paper also examines the sequence of nested equation systems that results from a hierarchical finite element formulation. Properties of these systems arising from static problems are investigated. The paper presents some new possibilities for iterative solution of hierarchic element equations, and different procedures are compared in a numerical example. Finally, a simple ID convection-diffusion problem clearly shows that the proposed hierarchical formulation in time gives a stable and accurate solution even for convection dominated flow.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260514
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    Announcement (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1240-1240 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260518
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  • 99
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    Masthead (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988) 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260601
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  • 100
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    Exact numerical solutions for radiative heat transfer in cylindrical furnaces (1988)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 26 (1988), S. 1201-1212 
    Details
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Exact expressions for the distributions of the components of radiative flux density and the radiative energy source term in terms of wall and medium temperature distributions have been formulated for an emitting absorbing medium of constant properties bounded by black walls of a cylindrical enclosure. The accuracy of numerical solutions has been tested on an idealized enclosure for which exact analytical solution of the expressions is possible and shown to have six-figure accuracy. The exact expressions have then been solved numerically for an enclosure problem based on data reported previously on a large scale experimental furnace. The principal feature of the data is highly non-uniform temperature distributions which are typical of the conditions encountered in industrial furnaces. These data have been chosen because of their practical importance and the non-availability of exact solutions for such data. The resulting exact solutions have been tabulated and are intended to serve in the future as standards for testing the accuracy of the approximate predictions produced using various three-dimensional flux models in cylindrical configurations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/nme.1620260513
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