Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1985-1989  (481)
  • 1970-1974  (2,290)
  • Industrial Chemistry  (2,037)
  • Electron microscopy  (734)
Source
Material
Years
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Diffusion barrier properties of the perineurium: an in vivo ionic lanthanum tracer study (1989)
    Springer
    Anatomy and embryology 180 (1989), S. 237-242 
    Details
    ISSN: 1432-0568
    Keywords: Perineurium ; Lanthanum ; Diffusion barriers ; In vivo ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary While the perineurium as a diffusion barrier has been extensively investigated by light and electron microscopy, copy, such studies have been largely restricted to the use of protein tracers. In the present study the permeability of the perineurium to a physiologically more relevant ionic tracer has been assessed. In vivo the rat sural or tibial nerve was either microinjected with lanthanum nitrate solution for endoneurial application or bathed in the lanthanum solution for epineurial application. The findings generally demonstrated an effective barrier to the tracer which failed to penetrate the inner layers of the perineurium. Only at the highest lanthanum concentration and longest time intervals employed did trace quantities occasionally penetrate the barrier and then only in the presence of some cytopathological changes to the outermost perineurial cells. The usefulness of the microinjection method was limited by the slight but unavoidable trauma to the perineurium. The findings are related to those of other studies which have used electron dense tracers, also to studies using physiological including electrophysiological techniques and morphological including freeze-fracture methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315882
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Synaptogenesis in the dorsal lateral geniculate nucleus of the rat (1989)
    Springer
    Anatomy and embryology 180 (1989), S. 243-257 
    Details
    ISSN: 1432-0568
    Keywords: Dorsal lateral geniculate nucleus ; Synapse formation ; Synaptic glomerulus ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Synapse formation and maturation were examined in the rat dorsal lateral geniculate nucleus (dLGN) from birth to adulthood. Examination of animals, whose ages were closely spaced in time, showed that the maturation of the synaptic organization of the nucleus takes place chiefly during the first 3 weeks of postnatal life. This period of maturation may be divided into 3 broad stages. During the first stage, which spans the first 4 days of life, there are only a few immature synapses scattered throughout the nucleus; occasionally aggregates of 3 or 4 synapses are encountered. Dendrodendritic synapses first appear at the end of this stage. The second stage, which lasts from the end of the first stage through day 8, is characterized by intensive synaptogenesis as well as extensive growth and degeneration. For the first time, large boutons resembling retinal terminals form multiple synaptic contacts with dendrites and dendritic protrusions; these synaptic arrangements are partially covered by glial processes. A feature characteristic of the developing dLGN during the first 2 postnatal weeks, and particularly during the second stage, is the presence of membrane specializations that resemble vacant postsynaptic densities. These specializations, which may be unapposed or opposite another neuronal process, decrease in frequency as the number of synapses increases. It is not known whether these densities are converted to synapses or whether they result from loss of presynaptic elements. The third stage in the process of synaptogenesis, which spans a period between days 10 and 20, is characterized by myelination and by the diminution of growth cones, degenerating profiles and vacant postsynaptic densities. There is also a very significant increase in the number and maturation of synapses including synaptic glomeruli. However, it is not until the end of this stage that synapses appear qualitatively indistinguishable from synaptic arrangements identified in adult animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315883
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Myelin breakdown in the posterior funiculus of the kitten after dorsal rhizotomy (1989)
    Springer
    Anatomy and embryology 180 (1989), S. 273-280 
    Details
    ISSN: 1432-0568
    Keywords: Wallerian degeneration ; Myelin breakdown ; Light microscopy ; Electron microscopy ; Marchi staining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphological aspects of myelin breakdown in the posterior funiculus during Wallerian degeneration were studied in kittens subjected to lumbosacral dorsal rhizotomies 6–8 days after birth. The first sign of myelin breakdown was characterized by swollen or shrunken nerve fibers. Shortly thereafter there was an increased occurrence of collapsed myelin sheaths and later of rounded myelin bodies. Myelin was clearly seen in microglial cells. Correlative observations on Marchi-stained material indicated the simultaneous and frequent appearance of Marchi-positive bodies (MPB:s) and myelin bodies. Due to the rapidity of the degeneration process in the kitten, the increase in the occurrence of Marchi-positive granules (MPG:s) seemed to start concomitantly with increased occurrence of MPB:s. However, the frequent occurrence of MPG:s outlasted that for MPB:s. The findings indicate that the MPB:s may be the counterpart to myelin bodies and the MPG:s to lipid droplets. Microglial cells may be responsible for the primary uptake of degenerating myelin and the subsequent transformation of myelin bodies to lipid droplets. The much faster breakdown of myelin and elimination of lipid material in the degenerating posteror funiculus of the kitten, as compared to the adult, seemed to be due not only to the lower myelin content in the kitten, but also to a higher density of microglia and a greater efficiency in the myelin breakdown process in the degenerating posterior funiculus of the kitten.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315885
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Hypomyelination in the neonatal rat central and peripheral nervous systems following tellurium intoxication (1989)
    Springer
    Acta neuropathologica 78 (1989), S. 301-309 
    Details
    ISSN: 1432-0533
    Keywords: Schwann cell ; Oligodendrocyte ; Electron microscopy ; Myelin ; Optic nerve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neonatal rats were exposed to Tellurium (Te), via the mother's milk, from the day of birth until sacrifice at 7, 14, 21, and 28 days of age. Light and electron microscopy revealed Schwann cell and myelin degeneration in the sciatic nerves at each age studied. These changes were similar to those described in weanling rats as a result of Te intoxication. In the CNS, hypomyelination of the optic nerves was convincingly demonstrated at 14, 21, and 28 days of age, accompanied by some evidence of myelin degeneration. These changes were also seen in the ventral columns of the cervical spinal cords, although less markedly, and were confirmed by quantitative methods. There was little evidence of oligodendrocyte pathology in the CNS, and it appears that degeneration of these cells is not the primary cause of the CNS hypomyelination, in contrast to the PNS where Schwann cell degeneration has been shown to precede the myelin pathology.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687760
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Pick bodies in the locus ceruleus (1989)
    Springer
    Acta neuropathologica 79 (1989), S. 10-17 
    Details
    ISSN: 1432-0533
    Keywords: Locus ceruleus ; Pick bodies ; Lewy bodies ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In classical Pick's disease with typical Pick bodies, inclusions resembling those present in the cerebral cortex are frequently found in the locus ceruleus. In three such cases Pick bodies were studied by light and electron microscopy and compared with Lewy bodies, inclusions more commonly found in this location. In contrast to the situation in the cerebral cortex, nerve cells with multiple Pick bodies were often found in the locus ceruleus, but in other respects definite light and electron microscopic differences between Pick bodies and Lewy bodies were present. Pick bodies were slightly basophilic and never had a central core or a peripheral halo. They were intensely argyrophilic. Differences in immunocytochemical reactions were especially marked with antibodies to tau and to paired helical filaments. Pick bodies displayed an intense reaction with these two antibodies, contrasting with that of Lewy bodies, which either lacked reactivity or reacted in a peripheral band. By electron microscopy the Pick bodies were composed of random filaments with smooth contour, whereas typical Lewy bodies had fuzzy deposits on filaments that radiated from a central core. Pick bodies in the locus ceruleus therefore maintained their immunocytochemical and electron microscopic characteristics and did not take on the character of Lewy bodies. Such differences point to a different pathogenesis and perhaps etiology of these two types of inclusions and attest to the marked difference clinically and pathologically between Pick's and Parkinson's diseases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308950
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Electron microscopic and Golgi study in a case of hemimegalencephaly (1989)
    Springer
    Acta neuropathologica 77 (1989), S. 664-666 
    Details
    ISSN: 1432-0533
    Keywords: Hemimegalencephaly ; Golgi study ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Pathological findings in a case of hemimegalencephaly are presented. Hemispherectomy, performed because of intractable seizures, allowed an electron microscopic and Golgi study. Glial abnormalities consisted of hyperplasia of glia cells with giant astrocytes often containing several nuclei and proliferation of numerous Rosenthal fibers. Golgi stain showed many giant neurons with a perikaryon covered by perisomatic processes, and a complex dendritic tree. Glial abnormalities could be correlated with the firmness of the hemisphere and intense hypersignal on magnetic resonance imaging. Giant neurons were associated with an increase in size of the perikaryon and dendritic tree; this pattern suggests a polyploidy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687896
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Melanotic paraganglioma of the orbit: a case report (1989)
    Springer
    Acta neuropathologica 79 (1989), S. 340-346 
    Details
    ISSN: 1432-0533
    Keywords: Paraganglioma ; Melanin ; Orbit ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A paraganglioma of the orbit in a 21-year-old woman is presented, containing oculo-cutaneous melanin in many tumor cells, occasionally adjacent to neurosecretory granules, and in macrophages. This tumor expands the list of neuroectodermal tumors with potential melaninization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294673
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The astroblastoma and its possible cytogenic relationship to the tanycyte (1989)
    Springer
    Acta neuropathologica 78 (1989), S. 472-483 
    Details
    ISSN: 1432-0533
    Keywords: Astroblastoma ; Electron microscopy ; Immunohistochemistry ; Organ culture ; Tanycytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two examples of cerebral astroblastoma have been studied by electron microscopy and immunohistochemistry, one of them having been maintained in vitro in an organ-culture matrix system for 8 months and the explants studied by light and electron microscopy at different time intervals. The fine structural characteristics were those of a glial cell type with features intermediary between those of astrocytes and ependymocytes. They recapitulated the structure of the tanycyte, a glial precursor cell which is normally found scattered along the ependymal lining of the embryonal and neonatal mammalian brain, but is distinct from epithelial ependymocytes. The possible origin of some astroblastomas from such a cell would account for a number of characteristics in this enigmatic type of glioma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687708
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Sporadic motor neuron disease with Lewy body-like hyaline inclusions (1989)
    Springer
    Acta neuropathologica 78 (1989), S. 555-560 
    Details
    ISSN: 1432-0533
    Keywords: Sporadic motor neuron disease ; Lewy body-like hyaline inclusions ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Lewy body-like hyaline inclusions were immunocytochemically and electron microscopically investigated in a patient with sporadic motor neuron disease. The hyaline inclusions were chiefly observed within the perikarya of both normal-looking and chromatolytic anterior horn cells in the lumbar spinal cord, but some were detected in the axons and dendrites. Usually, a single inclusion was found in the perikaryon, but in rare cases two or more were observed. Immunocytochemically, these inclusions were intensely immunostained with anti-ubiquitin anti-body. Ultrastructurally, the hyaline inclusions were chiefly composed of randomly arranged linear structures associated with ribosome-like granules, varying from compactly arranged linear densities to more loosely packed ones. They contained scattered vesicles of various sizes and occasionally a focal accumulation of randomly arranged 10-nm neurofilaments or 13–25-nm filamentous structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Morphological studies on cerebral cortical lesions induced by transient ischemia in Mongolian gerbil —Diffuse and peripheral pallor of the neuronal perikarya (1989)
    Springer
    Acta neuropathologica 78 (1989), S. 1-8 
    Details
    ISSN: 1432-0533
    Keywords: Cerebral ischemia ; Ischemic neuronal injury ; Long-term recovery ; Mongolian gerbil ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Unilateral transient cerebral ischemia was produced in Mongolian gerbils by clipping the left common carotid artery for 1h. About 60% of the gerbils with neurological symptoms had post-ischemic seizures. The majority of those that had seizures died within a few days, and sections of their cerebral cortices contained many dark and shrunken neurons. However, the gerbils that did not have seizures survived without any severe complications. In the cerebral cortex of the latter, the neurons with diffuse or peripheral pallor of the perikarya were seen along with a small number of dark and shrunken neurons. Diffuse pallor occurred within a few hours following ischemia in layers III, V and VI, and disappeared 1 or 2 days after recirculation. Electron microscopically, these neurons showed dispersion of ribosomes, simple and elongated profiles of rough endoplasmic reticulum (r-ER), clustered vacuoles, and mild to moderate mitochondrial swelling. Occasional net-like tubulomembranous structures, probably derived from r-ER, were observed. On the other hand, peripheral pallor became apparent after 5 days following ischemia, usually involving layer II first and gradually extending to the deeper layers. Concomitantly, the amount of neuropil decreased and the dendrites exhibited tortuosity and irregularity in layer II. Electron microscopically, these neurons showed marked swelling of peripheral perikarya and polyribosomes and organelles were located peripherally to the nuclei. In addition, numerous degenerated axon terminals and distended dendrites were observed around the neurons. These observations indicate that diffuse pallor represents damage directly induced by ischemia and subsequent recirculation, while peripheral pallor is the delayed and remote effect of ischemia, probably due to degeneration of neuronal processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687395
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Disseminated human neurocysticercosis (1989)
    Springer
    Acta neuropathologica 78 (1989), S. 594-604 
    Details
    ISSN: 1432-0533
    Keywords: Neurocysticercosis ; Pathogenesis ; Histochemistry ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was based on two cases of disseminated human neurocysticercosis from India. The material availabel was examined grossly, and by light microscopy, histochemistry, immunomorphology and electron microscopy. The results showed that the parasites commonly embolized to the anatomically discernable gray-white matter junction of the brain and were located in cavities, the walls of which were dilated vascular channels. The parasite-nutrition process was through endocytosis and microtrichal activity. To camouflage themselves from the host-defense mechanisms, the parasites apparently covered themselves with host-tissue-like material. Host reactivity to the parasite was heralded morphologically by the physical anchoring of the parasite by activated endothelial cells, loss of the host-tissue-like cover and an acute polymorphonuclear leucocytic response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00691286
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Senile plaque-like structures: observation of a probably unknown type of senile plaque by periodic-acid methenamine silver (PAM) electron microscopy (1989)
    Springer
    Acta neuropathologica 78 (1989), S. 137-142 
    Details
    ISSN: 1432-0533
    Keywords: Senile plaque-like structure ; Periodicacid methenamine silver (PAM) method ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Numerous diffuse senile plaque-like structures (SPLSs) were found in the cerebral cortex from cases with dementia of the Alzheimer type by means of the methenamine-Bodian method. SPLSs varied in shape and size. They were never recognized in the original Bodian, PAS and Congo red preparations, but were positive with anti-β-protein immunostaining and periodic-acid methenamine silver (PAM) methods, which are thought to specifically stain amyloid substance. With PAM electron microscopy, we found sparse aggregations of amorphous, often ramified, structures with fine granular silver deposits in SPLS. Routine electron microscopic examination on the same portion where SPLS were confirmed by PAM electron microscopy revealed amorphous, partially fibrous structures. These structures might be amyloid or amyloid-precursor substance. In SPLSs only a few degenerated neurites and astrocytic processes with glycogen granules were seen. We consider SPLSs to be a kind of senile plaque.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688201
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Localization of aggregation substances of Enterococcus faecalis after induction by sex pheromones (1989)
    Springer
    Archives of microbiology 151 (1989), S. 491-497 
    Details
    ISSN: 1432-072X
    Keywords: Aggregation substance ; Enterococcus faecalis ; Electron microscopy ; Field emission scanning electron microscopy ; Immunogold labelling technique ; Sex pheromone system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution of sex pheromone induced aggregation substance was studied on the cell surface of various Enterococcus faecalis strains. In the accompanying paper we have shown that the aggregation substance appears as a layer of hairlike structures. Using direct and indirect immunogold technique, transmission electron microscopy and high resolution scanning electron microscopy we investigated the appearance and distribution of the aggregation substance. The “hairs” increase in number with increasing exposure to sex pheromones (maximum density: 1300/μm2). We show that these structures are unequally distributed over the cell surface, even if the cells were induced by sex pheromones for a long period of time. Statistical analysis of the unequal distribution indicates that aggregation substance is incorporated into pre-existing “old” cell-walls and that this incorporation shows a saturation ca. 40 min after addition of sex pheromones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00454864
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Neural crest origin of clear cell sarcoma of tendons and aponeuroses (1989)
    Springer
    Virchows Archiv 415 (1989), S. 51-60 
    Details
    ISSN: 1432-2307
    Keywords: Clear cell sarcoma ; Melanosomes ; Cytochemistry ; Electron microscopy ; Nude mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to clarify the histogenesis of clear cell sarcoma of tendons and aponeuroses (CCS), two cases of human and one nude mouse-transplanted CCS line were studied using an ultrastructural and enzyme cytochemical approach. Most of the tumour cells obtained from the primary and transplanted CCS demonstrated melanosomes in various stages of development within the cytoplasm, whereas no melanosomes could be identified in the metastatic CCS. However, cholinesterase and tyrosinase activities could be demonstrated not only in the melanotic primary and transplanted CCS but also in the amelanotic metastatic CCS. The results therefore support the hypothesis that CCS is a soft tissue tumour derived from the neural crest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718604
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    An immunohistochemically defined non-Hodgkin's lymphoma showing intercellular junctions (1989)
    Springer
    Virchows Archiv 415 (1989), S. 297-300 
    Details
    ISSN: 1432-2307
    Keywords: Non-Hodgkin's lymphoma ; Electron microscopy ; Immunohistochemistry ; Intercellular junction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A rare example of pleomorphic B cell non-Hodgkin's lymphoma is described in which tumour cells possessed simple intercellular junctions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00724918
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Immunocytochemical and morphometric analysis of acinar zymogen granules in human acute pancreatitis (1989)
    Springer
    Virchows Archiv 415 (1989), S. 115-124 
    Details
    ISSN: 1432-2307
    Keywords: Human acute pancreatitis ; Zymogen granules ; Acinar cells ; Electron microscopy ; Immunocytochemistry ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present study fine structural changes of acinar zymogen granules were investigated in human acute pancreatitis. Pancreatic tissue was obtained at surgery from 6 patients, prepared for ultrastructural analysis, and stained immunocytochemically for trypsinogen. Stereological parameters of zymogen granules were evaluated. The density of the immunocytochemical labelling for trypsinogen was estimated over zymogen granules, the rough endoplasmic reticulum, Golgi apparatus and the acinar lumina. In acute pancreatitis the number of zymogen granules was diminished and their size reduced. The density of the labelling for trypsinogen was unchanged over zymogen granules but showed a significant reduction over the rough endoplasmic reticulum, Golgi apparatus, and the acinar lumina. In general the integrity of zymogen granules was well preserved. Focally degenerative changes of zymogen granules and large autophagosomes were observed. From the immunogold labelling a disturbance of enzyme synthesis and secretion was suggested. Evidence is given that a disruption of the zymogen granule membranes and a fusion with lysosomal bodies might contribute to the pathogenesis of human acute pancreatitis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00784348
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Salivary gland myoepithelioma variants (1989)
    Springer
    Virchows Archiv 416 (1989), S. 25-42 
    Details
    ISSN: 1432-2307
    Keywords: Salivary gland ; Myoepithelioma ; Neoplasm ; Electron microscopy ; Immunohistochemistry ; Cytoplasmic filaments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histological and ultrastructural features of five major salivary gland tumours, which have little or no evidence of duct- or gland-type differentiation in routine sections, are described. Four of the cases have the tumour cells organized as narrow, anastomosing cords of cells separated by a myxoid and vascularized stroma; we have designated such lesions as reticular-type myoepitheliomas. The fifth case has a solid growth pattern and is largely composed of hyaline cells, that is, a plasmacytoid myoepithelioma. Ultrastructurally, one reticular myoepithelioma reveals myoepithelial cell differentiation with microfilament aggregates, while the other three examples are composed of modified myoepithelial cells displaying widened intercellular spaces, prominent synthesis of extracellular glycosaminoglycans, distinct basal lamina development, and obvious accumulations of cytoplasmic intermediate filaments. In electron micrographs, the modified myoepithelial cells of the plasmacytoid variant closely resemble the tumour cells in the reticular form. Three cases had expression of both glial fibrillary acid protein (GFAP) and vimentin, but only one of the myoepitheliomas contained muscle-specific actin. At least focally, each of the cases exhibited a considerable spectrum of cytokeratin filaments. Using double-labeled immunofluorescent microscopy of one reticular variant and the plasmacytoid myoepithelioma, there was individual tumour cell co-expression of GFAP and vimentin focally in the plasmacytoid myoepithelioma, but co-expression of cytokeratins 13, 16 and GFAP were not noted in either case. As expected, co-expression of high- and low-molecular weight cytokeratin filaments was wide-spread in both myoepitheliomas. Most described myoepitheliomas have a solid growth pattern and are composed of spindle and plasmacytoid cells, but based on cytological features and growth patterns in this series, it is apparent that polygonalshaped cells with novel architecture can occur in myoepitheliomas. The results also indicate the close relationship between pleomorphic adenoma and such variants of myoepithelioma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606467
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Early bronchopulmonary lesions in rat lung after normobaric 100% oxygen exposure and their evolution (1989)
    Springer
    Virchows Archiv 414 (1989), S. 135-145 
    Details
    ISSN: 1432-2307
    Keywords: Hyperoxia ; Lung broncho-vascular reaction ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to clarify the early phenomena involved in the lung reaction to hyperoxia, twenty adult male rats were exposed to 100% oxygen at 1 ATA. Morphological pulmonary lesions were detectable after only 24 h hyperoxia, and included vasoconstriction and perivascular oedema, bronchiolar constriction, and pericyte reaction. The lesions were irregularly scattered within the lung parenchyma and occurred preferentially in areas centred on bronchiolo-vascular stems. Even at the latest stages, pulmonary heterogeneity was obvious, from the coexistence of areas damaged at different times. Neuro-epithelial-bodies were found under the bronchiolar epithelium; the morphological aspect of the neuro-endocrine cells observed was consistent with hyperoxia-induced modulation of their secretory activity. Taken together, our findings show the speed of development of hyperoxia-induced pulmonary changes and raise some pathogenic considerations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718593
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Liver parenchymal cell parasitism in human visceral leishmaniasis (1989)
    Springer
    Virchows Archiv 415 (1989), S. 1-6 
    Details
    ISSN: 1432-2307
    Keywords: Visceral leishmaniasis ; L. donovani ; Parasitism ; Liver pathology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Liver parenchymal cell parasitism with the amastigotes form ofL. donovani was detected by electron microscopy in human visceral leishmaniasis. Endocytosis was considered to be the mechanism by which the leishmania entered the cell. Evidence of well preserved parasites within hepatocytes suggest this parasitism as a possible reservoir for recrudescence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718599
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Collagen secretion granules in reactive stromal myofibroblasts, with preliminary observations on their occurrence in spindle cell tumours (1989)
    Springer
    Virchows Archiv 415 (1989), S. 437-445 
    Details
    ISSN: 1432-2307
    Keywords: Collagen secretion granule ; Myofibroblast ; Spindle cell tumour ; Electron microscopy ; Diagnosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Collagen secretion granules, representing stages in the intracellular packaging, transport and secretion of collagen-fibril precursor, have been studied by transmission electron microscopy in non-neoplastic human myofibroblasts and in neoplastic cells from a preliminary study of tumours exclusively or partly of spindle cell type. Vesicles, newly separated from Golgi saccules and containing finely fibrillar material, were identified as early presecretory granules, the most immature type of granule. Later stages exhibited longitudinally arranged, densely fibrillar bundles. Subsequently, secretory granules developed more homogeneously dense content. Fibril-containing cisternae near the plasma membrane were interpreted as either endocytotic or lysosomal structures, or as participants in the final stages of secretion. The features by which collagen secretion granules can be distinguished from other Golgi products, in particular melanosomes, Weibel-Palade bodies and lysosomes, are pointed out. The significance of these organelles for cell identification and tumour diagnosis is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00747745
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Biologic roles of the innermost cell layer of the outer root sheath in human anagen hair follicle: further electron microscopic study (1989)
    Springer
    Archives of dermatological research 281 (1989), S. 254-259 
    Details
    ISSN: 1432-069X
    Keywords: Innermost cell layer ; Tonofilaments ; Huxley's cells ; Henle's cells ; Anagen hair follicles ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To elucidate the biologic roles and further cytologic characteristics of the innermost cell (IMC) layer of the outer root sheath (ORS), human anagen hair follicles were ultrastructurally examined. In the lower follicle, the transeversely running tonofilaments in the inner side of the cytoplasm of the IMCs showed a massive accumulation, facing the keratinized part of a Huxley's cell protruding through a Henle's pore. In a rare instance, a spindle-shaped cell was seen between the IMC layer and the keratinized Henle's layer. At the lower isthmus portion, some of the IMCs containing a large number of tonofilaments showed a partial degeneration of the inner side of the cytoplasm. More distally, intercellular spaces between the keratinized IMCs and keratinized Henle's cells were partly dilated and contained amorphous substances. It is suggested that the IMCs in the lower follicle may play a role to support and cover the inner hair structures, tightly as hoops of a barrel. In the isthmus portion, the IMCs may loosely support and guide the keratinized Henle's cells undergoing degeneration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00431059
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Netherton's syndrome: ultrastructure of the active lesion under retinoid therapy (1989)
    Springer
    Archives of dermatological research 281 (1989), S. 165-172 
    Details
    ISSN: 1432-069X
    Keywords: Netherton's syndrome ; Retinoid therapy ; Etretin ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A young female patient, expressing the symptom triad of Netherton's syndrome, i.e., ichthyosis linearis circumflexa Comèl, trichorrhexis invaginata and other hair shaft defects, and atopic diathesis, has been treated successfully with the new retinoid preparation Etretin. Our electron microscopical study especially focused on the ultrastructural effect on the characteristic, active part of the skin lesions, which is only found within a narrow borderline just preceding the lesion's margin. In untreated skin, this part is characterized by dermal inflammation, immigrating inflammatory cells, and specific keratinization disturbances: synthesis of keratinization proteins is suppressed, serum exudates invade the epidermis, either filling the intercellular spaces of the upper spinous and the granular layer as finely granular, amorphous material, or they are partly phagocytosed and lie within intracellular, round-oval inclusions. The portions of the lesions lying towards the center are unspecific and represent recovery stages, ultrastructurally resembling stages of normal wound repair. Oral therapy with Etretin did not heal the basic defect, but drastically reduced exoserosis and the deposition of intra- and extracellular material. Keratinization seemed to normalize. The condition of the hair was also improved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00456387
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Mitochondrial encephalomyopathy with pilovacuolar inclusion or phenocopy with mitochondrial artefact? (1989)
    Springer
    Journal of neurology 236 (1989), S. 361-363 
    Details
    ISSN: 1432-1459
    Keywords: Mitochondrial encephalomyopathy ; MELAS ; Mitochondrial inclusion ; Pilovacuolar inclusion ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The case of a 33-year-old man with clinical features of mitochondrial encephalomyopathy is presented. He suffered from recurrent cerebral infarctions, cerebellar ataxia, deafness, retinopathy, weakness, and cardiac and renal disorders. Biochemical and light microscope investigations of skeletal muscle did not show any mitochondrial abnormality. Electron microscopy revealed the presence of a hitherto unreported peculiar “pilovacuolar” inclusion in numerous mitochondria, composed of an electron dense pile or rod within a vacuole, while globular or crystalline inclusions were absent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314383
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Human fetal endometrium -light and electron microscopic study (1989)
    Springer
    Archives of gynecology and obstetrics 246 (1989), S. 169-179 
    Details
    ISSN: 1432-0711
    Keywords: Human fetal endometrium ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human fetal endometrium was examined by light and electron microscopy. Our study shows the following new morphological aspects: (1) Glands are already present. (2) Endometrium undergoes a maturation process during gestation and at late gestational age resembles late proliferative endometrium. (3) The nuclear bodies are present in cell nuclei throughout gestation. (4) Nucleolar channel systems (NCS) sometimes appear at a late gestational age. (5) Cells with the same morphology as that of endocrine cells are found in the basal layers of endometrium at a late gestational age. The significance of these morphological aspects is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00934078
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Rodent and primate adrenal medullary cells in vitro: phenotypic plasticity in response to coculture with C6 glioma cells or NGF (1989)
    Springer
    Experimental brain research 76 (1989), S. 38-46 
    Details
    ISSN: 1432-1106
    Keywords: Nerve growth factor ; C6 glioma cells ; Chromaffin cells histofluorescence ; Electron microscopy ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to maintain a chronic supply of growth factor for medulla cells in vitro, chromaffin cells from rat, African green monkeys and man were co-cultured with C6 glioma cells, which secrete growth factors that sustain sympathetic neurons in vitro. The response of chromaffin cells to coculture was compared to treatment of medullary cells with nerve growth factor (NGF) alone. Dispersed chromaffin cell preparations were obtained by a trypsin-collagenase procedure, and subjected to differential plating on collagen-coated surfaces. With both human and monkey tissue, non-chromaffin cells did attach to the culture plates and an enriched chromaffin cell population could be replated. Rat adrenal medulla cells survived very poorly in vitro and were not enriched in this procedure. Cultured human and monkey chromaffin cells survived as epithelial cells (50%) and showed neuritic outgrowth on 55 to 66% of the cells after eight days when treated with nerve growth factor (NGF). These cells showed strong catecholamine histofluorescence, tyrosine hydroxylase (TH) and dopamine beta hydroxylase (DBH) immunoreactivity. In contrast, only ten percent of adult rat chromaffin cells survived in culture, although NGF treatment rescued an additional 20% of the cells and induced neuritic outgrowth after one week in vitro. C6 glioma cells were treated with mitomycin C bromodeoxyuridine to inhibit mitosis and were plated with the various medulla cells in a one to one ratio. Both human and monkey chromaffin cells expressed extensive and enhanced neuritic arborization within eight days of co-culture, (64–82% respectively) and exhibited intimate contact with the glioma cells as seen at the ultrastructural level. Importantly, survival of adult rat adrenal medulla cells was enhanced to 50% or more with 40% of the cells extending neurites when co-cultured with glioma cells for seven days. Chromaffin cells from all three species reacted for TH, DBH and PNMT in co-culture and were histofluorescent. The majority of these cells were also immunoreactive for serotonin and enkephalin, while only 37% of chromaffin cells indicated the presence of NPY. These data indicate that adrenal medulla can be maintained in vitro as the neuronal phenotype when co-cultured with growth factor producing cells and that this strategy may be useful for in vivo transplantation studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00253621
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    An ultrastructural study of the hypertrophied human papillary muscle cell with special emphasis on specific staining patterns, mitochondrial projections and association between mitochondria and SR (1989)
    Springer
    Virchows Archiv 414 (1989), S. 187-198 
    Details
    ISSN: 1432-2307
    Keywords: Human heart ; Papillary muscle ; Hypertrophy ; Mitochondria ; Specific staining ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Biopsy material of the hypertrophied human papillary muscle has been processed according to various electron microscopical techniques in order to study the mitochondrial ultrastructure and the association between mitochondria and sarcoplasmic reticulum (SR).En bloc staining with a Cu-Pb citrate solution resulted in specifically contrasted mitochondrial and sarcotubular membranes, characterized by numerous, discrete, electron-dense particles. The differences in staining patterns between the perinuclear mitochondria and their subsarcolemmal and interfibrillar counterparts suggest differences in chemical properties and/or metabolic activities. The selectively contrasted mitochondrial particles may represent a conglomorate of extrinisic and intrinisic respiratory enzymes and other membrane-associated proteins, while the majority of the electron-dense particles of the sarcotubular membrane may represent positively stained Ca2+-pumps. Ultrastructural findings in the present study strongly indicate that the slender mitochondrial projections represent an initial stage in a process leading to the formation of large and pleomorphic mitochondria. Intimate contact between adjacent mitochondria as well as between mitochondria and SR are documented. In the contact regions some of the specifically contrasted particles of the adjacent membranes had fused with each other. It is suggested that these particles represent membrane-bound transport proteins providing a system for interorganelle exchanges of metabolites and/or ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00822022
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Ultrastructural and electron immunohistochemical features of medullary thyroid carcinoma (1989)
    Springer
    Virchows Archiv 414 (1989), S. 375-384 
    Details
    ISSN: 1432-2307
    Keywords: Thyroid neoplasms ; Electron microscopy ; Immunohistochemistry ; Calcitonin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural study, both morphological and immunohistochemical, has been carried out on eight thyroglobulin-positive and nine thyroglobulin-negative medullary carcinomas of the thyroid. The morphometric analysis of granule size showed that all tumours contained cells with small granules and cells with medium size granules, whereas eight tumours had additional cells with large granules. The small granules had an electron dense core, while the medium and large sized granules were both pale-cored and dense-cored. The cells with small, medium or large secretory granules were all immunoreactive for calcitonin and CGRP. No ultrastructural differences were observed between thyroglobulin-positive and thyroglobulin-negative cases of medullary carcinoma of the thyroid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718620
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Carcinosarcoma of the urinary bladder (1989)
    Springer
    Virchows Archiv 415 (1989), S. 91-95 
    Details
    ISSN: 1432-2307
    Keywords: Carcinosarcoma ; Urinary bladder ; Immunohistochemistry ; Electron microscopy ; Rhabdomyoblast
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of urinary bladder carcinosarcoma (UBCS) is reported with light, immunohistochemical and electron microscopical findings. The tumour consisted of a squamous cell carcinoma, variable spindle cell stromal elements compatible with fibrosarcoma, and rhabdomyoblasts. Intermediate filament co-expression of cytokeratin and vimentin was shown by immunohistochemistry. Electron microscopy (EM) confirmed the nature of the three components, and indicated some similarities between the three cell-types present. Comparisons with the previous UBCS in the literature are made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718608
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    A histopathological study on the prognosis of childhood IgA nephropathy and glomerular basement membrane lesions (1989)
    Springer
    Pediatric nephrology 3 (1989), S. 242-247 
    Details
    ISSN: 1432-198X
    Keywords: IgA nephropathy ; Electron microscopy ; Glomerular basement membrane lesions ; Prognosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Seventy-three patients with IgA nephropathy (IgAGN), under the age of 15 years at the time of the discovery of the disease, were investigated with respect to glomerular basement membrane (GBM) lesions. Irregular attenuation or widening of GBM, especially on the epithelial side, was observed in 28 cases (38%). These two changes are referred to aslysis of GBM and were considered to be the primary and specific changes among the GBM lesions in IgAGN. GBM thickening with layering of lamina densa was found in 37 of 73 cases (51%), but this change has been observed in other types of glomerular diseases. GBM lesions similar to those seen in IgAGN were also observed in Henoch-Schönlein purpura nephritis (HSPN) and poststreptococcal acute glomerulonephritis (PSAGN). Lysis of GBM was observed only in IgAGN, HSPN and PSAGN. Subepithelial and intramembranous deposits appeared to have an important role in the development of these GBM lesions. The presence of GBM lesions was correlated with a high incidence of cellular crescents but not with other clinical or light microscopic findings. The presence of these GBM lesions in IgAGN does not have a significant effect on the prognosis, at least in childhood. The affected GBM seemed to recover without leaving any significant residual damage in most cases. In the long-term prognosis of the disease non-immunological factors, such as ageing or hypertension, seem to be important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00858523
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Retinal axons innervate the embryonic chick diencephalon in an in-vivo-like pattern in expiant co-cultures (1989)
    Springer
    Experimental brain research 75 (1989), S. 563-568 
    Details
    ISSN: 1432-1106
    Keywords: Retina ; Diencephalon ; Co-culture ; Synapses ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Explants of chick embryo diencephalon co-cultured with explants of retina display areas of complex neuropil containing large retinal-like endings which establish synaptic contact with conventional and presynaptic dendrites. Transection of fibre bundles linking retinal to diencephalic explants results in the degeneration of endings of this type, suggesting that axons of extrinsic (retinal) origin innervate the diencephalic explants in an in-vivo-like manner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249907
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    A quantitative analysis of the synaptic development of the lobus parolfactorius of the chick (Gallus domesticus) (1989)
    Springer
    Experimental brain research 78 (1989), S. 425-434 
    Details
    ISSN: 1432-1106
    Keywords: Avian forebrain ; Synapses ; Stereology ; Disector ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The lobus parolfactorius (LPO) of the chick has been shown to undergo an increase in the mean synaptic numerical density (Nv syn) in response to one-trial passive avoidance learning (Stewart et al. 1987). The present study was undertaken in order to describe the pattern of normal development of synapses in the LPO, to further investigate the significance of this plastic response. The LPO's from each hemisphere of pre-hatch (16 days), and post-hatch (1 day, 9 day and 22 day old) chicks were processed for electron microscopy. Synapses were classified into asymmetric spine, asymmetric shaft, symmetric spine, and symmetric shaft synapses, on the basis of the density of the post-synaptic thickening and the nature of the post-synaptic target. A 3-dimensional stereological probe was used (the ‘disector’) to calculate Nv syp, and mean projected height (H syp) of the post-synaptic density (PSD). Mean values for each age and hemisphere were compared with a 2-way analysis of variance test using paired samples. A six-fold increase in Nv syp was seen between 16 days in ovo, and 9 days post-hatch. There was a hemispheric asymmetry at 9 days post-hatch, with the left hemisphere LPO containing 1.6 times as many synapses per μm-3. There was a subsequent period of reduction in synaptic density in the left hemisphere LPO between 9 and 22 days post-hatch. The Nv of all classes of synapse increased with age, but the proportions of the symmetrical synapses with respect to the total number of synapses, decreased with age. This decrease was of a similar magnitude for each hemisphere. A hemispheric difference was seen in post-hatch asymmetric synapses, with a greater proportion of asymmetric spine synapses in the left hemisphere. The magnitude of the hemispheric asymmetry was constant throughout the 3 week period of post-hatch development, but was not present in pre-hatch chicks. The PSD increased in length in each hemisphere by approximately 40% between post-hatch day 1 and post-hatch day 9. These data show that the LPO contains a synaptic population which undergoes substantial modification during the first week post-hatch. An asymmetry exists at post-hatch day 9 which is not present at the earlier ages investigated, nor indeed after 22 days post-hatch. This may have significance with regard to studies of passive avoidance learning in the one-day old chick, where an increase in both the size and number of synapses in the LPO has been demonstrated (Stewart et al. 1987). It is possible that ‘training’, in this situation, may simply enhance the timing of synaptic events that result as a consequence of normal development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00228916
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    An experimental study of mucociliary pathology of the eustachian tube in otitis media with effusion induced by irradiation (1989)
    Springer
    European archives of oto-rhino-laryngology and head & neck 246 (1989), S. 428-432 
    Details
    ISSN: 1434-4726
    Keywords: Otitis media with effusion ; Mucociliary system ; Eustachian tube ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have examined the function and fine structure of the mucociliary system of the eustachian tube in an experimental study of otitis media with effusion induced by X-ray irradiation. Functional examination demonstrated that the ciliary activity was diminished in such a condition, while morphological observations showed pathological findings including compound cilia, vacuolation of ciliated cells and expansion of intercellular space. These findings show that irradiation-induced otitis media with effusion results in impairment of the mucociliary system. As evidenced by these studies, the mucociliary system in the eustachian tube has an important role in the clearance of fluid produced in the tympanic cavity as well as affording improvement in this disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464303
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Synovial lining cells (1989)
    Springer
    Rheumatology international 9 (1989), S. 49-51 
    Details
    ISSN: 1437-160X
    Keywords: Synovium ; Monoclonal antibodies ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cells making up the lining of the synovium have long been known as type A and B synoviocytes, with an intermediate form sometimes also described. Accumulating evidence shows that the type A cells are macrophages and the type B cells are fibroblasts. Recently, a definite orientation of these cells within the synovial lining has been observed. The number of synovial lining cells increases in joint disease, and this now seems more likely to be due to cellular recruitment rather than local proliferation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270244
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Revascularization of isolated autologous bone grafts following microsurgical implantation of arteries and veins (1989)
    Springer
    European journal of plastic surgery 12 (1989), S. 29-34 
    Details
    ISSN: 1435-0130
    Keywords: Revascularization ; Vessel implantation ; Bone grafts ; Corrosion casts ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The microsurgical implantation of a saphenous vascular axis into free transplanted autologous isolated rib segments in Beagle dogs led to complete revascularization of the bone after two, three and four weeks. Indian ink and Mercox-injected specimens showed a vascular network which penetrated the entire cortical layer. Semi-thin sections revealed osteoblasts and osteoclasts visible in the canals of the revascularized cortical layer, while the control specimen without vessel implantation showed nothing but ground substance. The revascularized bones did not contain any necrotic areas. The newly formed vascular system consisted of arteries, veins and their anastomoses. The veins appeared to produce a greater number of new vessels than the arteries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00226918
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Studies in liquid-liquid direct-contact heat transferPaper presented by E. Marschall at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 388-394 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Liquid-liquid direct-contact heat transfer in a spray column was studied numerically for a low hold-up. The solutions of the conservation equations of mass, momentum and energy for both phases agree well with earlier experimental results, if one assumes a rigid liquid-liquid interface. Heat transfer inside is dominated by transient conduction and natural convection. It was found that the Nusselt number for free convection depends essentially only on the Rayleigh number.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120155
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Directional specific shear-rate measurements in gas-liquid two-phase flow (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 374-378 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Wall shear rate vectors in a bubble column and an airlift-loop reactor were measured using the limiting-current electrodiffusion technique. In connection with a new circular three-segment probe, the magnitudes and directions of shear rates were determined. The results for the bubble column are in good agreement with hot film-anemometry measurements in the same column. Moreover, the spiral flow structure, postulated in the shear-zone model of Franz, has been confirmed. In addition, the measuring technique was used to determine the flow structure in an airlift-loop reactor employed for the cultivation of animal cells. The region above the gas distributor of this fermenter has been identified as critical for mechanical damage to the cells.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120153
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Overproduction of lipase with staphylococcus carnosus (pLipPS1) under modified gravity in a centrifugal field bioreactorReport from SFB 145 “Biological, chemical and technical fundamentals of bioconversion” (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 364-373 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fermentation under modified gravity could be of interest in application to (a) increasing productivity of growth and growth linked production with microorganisms at high cell densities and (b) increasing the productivity of highly viscous pseudoplastic polysaccharide fermentation. In both cases, higher oxygen transfer rates in centrifugal fields result in higher productivities since these fermentations are usually oxygen limited. A further aspect of fermentation under increased gravity is the reduction of foam since foam coalescence time decreases with acceleration number. On the other hand, under microgravity, shear reduction would allow growth and production even for very shear sensitive organisms. In order to carry out fermentations under modified gravity, a special type of fermenter-the centrifugal field bioreactor CFBR-has been developed at the Institute of Chemical Engineering (Head: Prof. Mersmann) of the Technical University of Munich. For the first time, exoprotein biosynthesis of lipase with S. carnosus has been carried out under sterile and controlled conditions in this novel bioreactor, in presence of increased mass forces.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120152
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Measurement of heat transfer coefficients in tubes by temperature oscillation analysisPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 379-387 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An experimental technique and evaluation method is described for the determination of local heat transfer coefficients in tubes or other ducts. By means of a rotary mixing valve, cold and warm fluid flows are mixed in order to generate an arbitrarily shaped but periodically oscillating inlet temperature profile at the test tube. The propagation of the fundamental harmonic oscillation from the fluid to the outer surface of the tube wall is calculated analytically. Comparison of fluid and wall oscillations yields the heat transfer coefficient to be measured. The inaccurate measurement of fluid bulk temperature in the centre of the cross-section is compensated by an additional correction. Experiments were carried out with turbulent water flow through a copper tube. Measured heat transfer coefficients were compared to values calculated using Hausen's equation and good agreement was obtained.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120154
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Effect of transfer on droplet size in liquid-liquid dispersions (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 395-399 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mean droplet diameter of the dispersed phase in pulsed plate extraction columns was measured for binary and ternary systems. A change in the droplet size in the presence of solute, dependent on such factors as the direction of mass transfer, droplet size in the binary system, radio of diffusion coefficients, viscosity of the continuous phase, interfacial tension and driving force for extraction was observed. Two new empirical correlations of mean droplet sizes in mass transfer conditions are proposed. These correlations have been successfully applied to other extraction columns.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120156
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Evaporation rate and separation factor of molecular distillation in a falling film apparatus (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 406-413 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: During molecular distillation in a falling film apparatus, temperature and concentration of the more volatile components undergo a marked decrease in axial and radial directions, due to the distillation in vacuo. The gradients produce changes in the rate of surface evaporation and separation efficiency along the flow path. A theoretical study of this problem is presented for binary mixtures. The respective differential equations for heat and mass transfer in the liquid film are solved numerically. As the results demonstrate, the aspect ratio of an apparatus should be large when a high separation is required and small when a high distillation rate is more important.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120158
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Flow phenomena and local heat and mass transfer in corrugated passagesPaper presented by G. Gaiser at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 400-405 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Flow phenomena, local heat and mass transfer and pressure drop of corrugated passages in process equipment are examined. Based on a method for measuring local heat and mass transfer, developed in previous investigations, a procedure has been formulated for the determination of local heat and mass transfer in corrugated passages. Using the analogy between heat and mass transfer, this technique allows the determination of heat transfer distributions in any structures with high local resolution. The corresponding pressure drop is presented together with the local and integral heat and mass transfer of different structures. It is shown that differences in heat and mass transfer as well as in pressure drop are due to different flow phenomena which also characterize mixing behaviour.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120157
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Parameters influencing the mean particle size of a crystalline productPaper presented by A.B. Mersmann at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988.Dedicated to Professor Dr.-Ing. Dr. h.c. Ernst-Ulrich Schlünder on the occasion of his 60th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 414-419 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Crystallizer design has to take into account the physical and chemical properties of the solution and solids as well as the geometry, type and operating conditions of the crystallizer. The most important property of a crystallizing system is its solubility. High solubility leads to low relative supersaturation and large mean crystal size, and vice versa. High solubility systems can be sensitive to abrasion and attrition. For low solubility systems, mixing is crucial.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120159
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    The importance of dynamic performance and testing of industrial thermometers in process control (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 419-426 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper considers the dynamic performance of instruments in control systems. Errors connected with transient measurements are discussed. It is shown that it is not always proper to assign common statistical properties to these dynamic errors. Emphasis is placed on temperature sensors. Common industrial thermometers are described and factors affecting their response discussed. An a-priori dynamic performance prediction procedure is presented. This permits preinstallation estimation of response characteristics of sensors used in industrial processes. Sensors in service also require performance assessment since they can deteriorate with use. In-situ testing is useful for this purpose and a recently develolped procedure is described.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120160
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Modelling and simulation of monopropellant hydrazine thrusters for spacecraft position controlDedicated to Professor Dr. Dr. h.c. Ewald Wicke on the occasion of his 75th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 426-432 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Modelling of the kinetics of a 20-N hydrazine thruster is carried out by considering two different heterogeneous reaction channels for hydrazine decomposition to the intermediate ammonia. The parameters of the reactor model are estimated by making use of temperature profiles at the wall of the decomposition chamber. Simulated ageing of the catalyst revealed an increase of the rate of deactivation with increasing total firing time.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120161
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    On-line measurement of partical size distribution and partical concentration in suspensions by ultrasonic spectrometryPaper presented by U. Riebel at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 433-438 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The principle of ultrasonic spectrometry is based on the measurement of the ultrasonic extinction caused by the presence of particles. From measurements at different frequencies and with the knowledge of the ultrasonic extinction cross section of the particles, a system of linear equations can be established and solved to obtain the particle size distribution and particle concentration. With an experimental apparatus covering the frequency range from 1.7 MHz to 81 MHz, particles ranging from 20 to 1000 μm in diameter may be analyzed. The measurements can be carried out with particle concentrations as high as 10% by volume.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120162
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Investigation of a wet dust scrubber with a pneumatic nozzle: Dust collection based on turbulent diffusionPaper presented by P. Centner at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 439-444 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The “nozzle scrubber” is a wet scrubber in which the scrubbing water is dispersed in dust laden gas stream by means of one or more pneumatic nozzle. This scrubber is distinguished by an excellent collection efficiency for submicron dust at an unusually low energy and water consumption. So far, the physical effects affecting the separation cannot be explained by a well-defined theory. Therefore, it is sensible to investigate the collection efficiency with regard to the mechanisms of inertial impaction, turbulent diffusion and coalescence induced by turbulence. The experimental equipment is of a very simple design. A light scattering device was used to measure the particle distributions. In addition, electron micrographs were analyzed to obtain information about the submicron particles. The influence of operating parameters on grade efficiency has been demonstrated by their systematic variation. The contribution of turbulent diffusion to the collection efficiency has been confirmed; nevertheless, grade efficiencies were also measured when inertial impaction prevailed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120163
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    A study of gas and liquid distributions in structured packingsPaper presented by R. Stikkelman at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 445-449 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study describes the gas and liquid distributions in a column with structured packings. The column is 0.5 m in diameter. It is equipped with a total of 1289 detectors in the top and bottom cross-sections. These detectors provide a detailed picture of the gas and liquid flows through elements of only 25 × 25 mm2. The maldistribution in the gas bulk flow is negligible. Only the observed wall can contribute to malperformance. The gas flows in parallel to sheet orientation, thus introducing a radial transport. Together with the change in the orientation of subsequent packing elements, this results in good gas mixing. It was observed that the liquid wall flow rate decreases when the gas velocity exceeds 1.7 m/s. Up to the loading point, the maldistribution of the liquid is constant. Above this point, the equality of the distribution deteriorates rapidly, due to the occurrence of large-scale liquid segregation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120164
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Heat and mass transfer during condensation of steam in the presence of air at pressures of up to 21 bar (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 235-244 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Film theory under consideration of one-sided diffusion is a satisfactory basis for the calculation of vapour condensation from a flowing turbulent mixture with non-condensable gases. At atmospheric pressure and low condensate flow rates, coefficient equations for smooth tubes are used as a rule. At higher pressures and thus, at higher temperatures and gas densities, there are additional parameters. For instance, non-ideal behaviour of the gas phase or the surface roughness affects the condensation process. These parameters were examined in a test plant under variation of pressure, steam concentration and temperature in a vapour/air mixture. At pressures of up to 21 bar, the Reynolds number of the gaseous phase reaches a maximum value of 128 000 and of 720 for the condensed phase. After description of the test facility, the experimental results are explained and discussed. It is shown that the experimental results are not in a good agreement with the common calculating methods. Taking into account the non-ideal behaviour of the steam/air mixture and the roughness of condensate surface by using a friction factor ξr, all the results could be calculated with an accuracy of ± 20%. This was achived with a modification of the coefficient equation of Gnielinski [1] and by using the equation of Andreussi [2] for the friction factor of a cocurrent annular flow. With respect to one-sided diffusion, the film theory is still applicable. The described method for the determination of local transfer coefficients includes the common calculating method. It represents an extension of the general validity of the film theory.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120132
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Study of mass transfer in a centrifugal film apparatus (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 245-248 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mass transfer data are presented for absorption of oxygen in a centrifugal film apparatus. The apparatus was designed to exclude the formation of foam by gas dispersion in liquid. Cells and micro-organisms are not subjected to high shear stress. Therefore, this equipment can be applied in fermentation processes. In the present work, experimental data and correlations were obtained on splitting of the liquid film and oxygen absorption into the film through a spiral ridge formed on the conical surface. The performance of the apparatus is found to be equivalent to those of other types of absorbers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120133
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Thermally stabilized combustionPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 249-254 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Thermally stabilized combustion has a number of unique characteristics which permit the generation of steam or other forms of process energy from the heat of combustion of a gaseous or clean liquid fuel in remarkably compact, integrated apparatus while truly minimizing the concentrations of NOx, CO and unburnt fuel in the effluent. These characteristics, which have been identified by a long-range program of research, are described and the advantages and limitations of this process are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120134
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Parameter estimation from integral Mars-van Krevelen type of kinetic data of a reaction networkDedicated to Professor Dr. Horst Langemann on the occasion of his 60th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 11-14 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120103
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Coupled simulation of heat transfer and reaction in a steam reforming furnaceDedicated to Professor Dr. Hanns Hofmann on the occasion of his 65th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 20-26 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: For design and simulation of chemical process furnaces in accordance with present-day standards, the temperature distributions in the firebox and in the reactors must be generated simultaneously. This calls for coupling of the simulations of the firebox and of the reactor. For the calculation of heat transfer in the firebox, a generalized furnace simulations program, based on the zone method, is applied. Monte Carlo simulation techniques are used to determine the view factors. The location of the burners is explicitly accounted for. Absorption and emission of radiation by the flue gas are calculated by considering band contributions for carbon dioxide and water. For the simulation of the steam reforming reactors, a one-dimensional heterogeneous model, which accounts for the presence of intraparticle partial pressure gradients, is used. The simulated temperature distribution in the furnace is in excellent agreement with industrial results, as is the simulated product distribution.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120105
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Generalization of AIChE and colburn models for tray efficiency (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 333-339 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The most important investigations on liquid weeping and entrainment in plate columns with downcomers are reveiwed. The formulae for calculating column plate efficiency under conditions of liquid weeping and entrainment have been derived on the basis of mass balance equations. The presented model is a generalization of the models of AIChE and Colburn. Sample results are shown graphically. The effect of liquid entrainment on tray efficiency predicted by the model is in agreement with experimental data of FRI.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120146
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Heat transfer to liquids and suspensions in agitated narrow vesselsPaper presented by D.-H. Frobese at the “Jahrestreffen der Verfahrensingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 324-332 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The knowledge of the heat transfer coefficient on the inner side of a heated vessel wall is of the utmost importance for the design of agitated vessels. In the case of large Reynolds numbers, the heat transfer is mainly determined by these numbers whereas, with small Reynolds numbers, the heat transfer is better described by considering the Grashof number. Investigations of heat transfer in agitated narrow vessels have shown that the height/diameter ratio exerts virtually no influence on the heat transfer when multi-impeller stirrers are used. The heat transfer to stirred suspensions can be described by relationships valid for liquids if the characteristic data of the liquid are replaced by those of the suspension and when the solids volume concentration is also taken into account. This relationship allows the heat transfer coefficient to be calculated for given solids volume concentrations of up to 60%.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120145
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Design and analysis of a state observer for the temperature front of a retification columnExtended version of a paper presented by G. Feig at the “Jahrestreffen der Verfahrens-Ingenieure”, Hannover, September 21 to 23, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 339-344 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to achieve optimal energy-saving, load-dependent operation of rectification columns, development and implementation of model-based control concepts are necessary. This paper reports on the design and step-by-step testing of a state observer for the estimation of two state variables which cannot be measured directly, namely the vapour rate and the location of mass transfer zone (temperature front) in the stripping section of a production column. The procedure is described, and the relevant simulation and operation results are presented and discussed. Initial experience, gained when the concept was put into practical operation, is reported.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120147
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    Continuous crystallization of potassium carbonate (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 345-350 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous crystallization of potassium carbonate was investigated in a mixed suspension mixed product removal (MSMPR) crystallizer with 7.0 1 working volume. Highly polydispersed product was obtained, with x50 varying between 320 and 670 μm. Crystal growth rates can be described by the model of Abegg, Stevens and Larson (ASL) (size dependent crystal growth rate). Values of G0 = 8.6 × 10-9 to 3.6 × 10-8 m/s and B0/ϕ = 2.7 × 108 to 4.2 × 109 1/m3s were obtained for mT = 45 to 92 kg/m3 and ε = 0.45 ± 0.05 W/kg. Nucleation kinetics at 27 °C can be described by the equation: B0/ϕ = kBϕsε0.73G02.5. Since G0 ∝ σ, convection and/or diffusion rather than surface integration are the crystal growth controlling mechanisms.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120148
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Selective absorption of ethylene by methanol solutions of Copper(I) chloride-ethylenediamine complex (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 356-357 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120150
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Separation of liquid from vapour upon pressure relief (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 54-63 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: When a chemical reactor is depressurized or pressure in a vessel, filled with saturated liquid, has to be decreased, generally both vapour and liquid flow out through the relief valve. Since chemical reactors are usually operated with toxic and explosive fluids, the discharged liquid which vaporizes on the ground around the vessel may reach dangerous concentrations, causing explosions or accidents with the poisonous gas. During a research project, some fundamentals were developed for the design of separation systems which separate liquid from vapour and store it in a receiver. The requirement for a separation efficiency of a least 80% is related to the condition that the separated liquid should flow back into the reactor still during the pressure relief phase. For safety reasons, both separation and re-storage are to be carried out without the supply of external energy. Theoretical and experimental investigations of pressure distribution within the piping to the relief valve and in an integrated separator show that re-storage of the separated liquid in the vessel can be achieved under certain flow conditions. Therefore, the separator must be integrated in the pipe at a certain height above the vessel, so that the hydrostatic pressure of the separated liquid, corresponding to the difference in height, is sufficient to lead it back through another pipe against the internal pressure of the vessel. First, several separators were tested with air-water mixtures. A swirl separator and a reversing separator have been developed to such an extent that they appear suitable for the set task. Experimental results with air-water mixtures and refrigerant R12 upon pressure relief show separation efficiencies of between 90 and 100% at low pressure drops within the whole operating range. As an alternative to separation outside the vessel, a rotary separator was also developed which is fixed to the outlet opening in the vessel. A centrifugal field is produced by the separator rotor and the heavier liquid is largely separated from the vapour so that only drops in the range 〈 100 μm flow together with the vapour towards the central standpipe. The outflowing vapour leaves the separator via 4 tangentially arranged nozzles, under critical conditions. The vapour flow momentum drives the separator rotor. The arrangement was developed and tested during various series of experiments, under conditions or pressure relief with refrigerant R12. So far, separation efficiencies between 60 and 95% have been achieved at stirring speeds of up to 2500 min-1.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120110
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    The pressure ratio of critical two-phase flowsDedicated to Professor Dr. h.c. Dr.-Ing. Heinz Brauer on the occasion of his 65th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 89-96 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Depressurization of a pressure vessel, containing a liquid or a gas is limited by the maximum possible mass flux. This flux occurs at a certain drop in pressure. The ratio of ambient pressure to that inside the vessel must be less than a certain critical value. The critical pressure ratio depends on the thermodynamic state of the fluid inside the vessel and on the geometry of the outlet cross-section. The outlet can be a pipeline, a safety valve or a rupture disk. The results of known theoretical and experimental work are presented. In previous experiments, saturated liquids, two-phase flows or pure vapours were examined. In order to predict the critical pressure ratio, certain assumptions are necessary. These are derived for three well-defined cross-sections of the vessel outlet.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120113
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Simulation of sintering of model supported metal catalysts (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 103-109 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: During the past decade, the sintering of model supported metal catalysts, i.e. catalysts consisting of metal deposited on very thin and flat oxide films, has been intensively investigated by transmission electron microscopy. In the current paper, a mathematical model, based on an atomic migration mechanism, for the sintering of these catalysts is presented. The predictions of the model, based on Monte Carlo simulations, are in very good agreement with the experimental observations, i.e. phenomena such as ‘apparent’ particle migration, splitting and neck formation between particles are predicated by the model.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120115
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Combined process treatment of molasses fermentation waste water for biogas generation (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 109-112 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Anaerobic fermentation of molasses distillery slops to biogas was carried out with the aid of an adapted and selected anaerobic mixed culture. Two different types of fermenters were used, namely an agitated pretreatment fermenter and a column fermenter with glass rings as carriers for micro-organisms. The production of biogas in both fermenters amounted to between 0.6 and 0.8 dm3/g COD. The aerobic pretreatment of distillery slops by T. fermentans, yeast during a 4 to 6 h period allows a high reduction of COD in the subsequent anaerobic phase of the process. After treatment of the distillery slops by T. fermentans, it was possible to convert between 85 and 93% of the organic matter to methane. Conversion was about 93% with loading rate of 25g COD/litre day.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120116
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Conversion of methanol to light olefins over zeolite H-T (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 155-161 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The conversion of methanol over zeolite H-T was investigated in a fixed bed reactor. H-T was prepared from Na-T by ion exchange with HCl and NH4Cl solutions. The HCl solution caused appreciable dealumination. High yields of ethene were obtained with NH4Cl exchangeed zeolites Na-T with 45% decationization, high proprne yields with low HCl or NH4Cl Exchanged catalysts. Low methanol partial pressures and short residence times favoured the formation of lower olefins. Lowest coking rates were observed at a reaction temperature of 693 K. The catalytic activity decrased slowly with the number of reaction/regeneration cycles. The distribution of procucts 〉 C2 could be described by the most probable distribution of Schulz and Flory.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120121
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Advances in modelling and design of multitubular fixed-bed reactorsII. A Mathematical Model of the Cocurrent Multitubular Reactor System (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 170-175 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents a method mathematical modelling of cocurrent multitubular fixed-bed reactors. The method is adapted to the most widespread type of industrial reactor design, i.e. the system fitted with disk-and-doughnut baffles. The proposed model makes it possible to estimate the influence of non-uniformity of the heat carrier flow on the reactor characteristics, taking into account the coolant streams by-passing via the tube-to-baffle clearances. Based on the model, the effect of the operating parameters as well as of some more important geometrical parameters of the reactor on an exemplary highly exothermic process of partial benzene oxidation to maleic anhydride is discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Venturi scrubber calculation and optimization (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 188-195 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Collection efficiency and pressure loss of a venturi scrubber can usually be determined from the calculation models of Barth and Calvert. However, this only leads to reasonable results if the droplets are uniformly distributed throughout each cross-section of the washing zone. In this work, a two-zone models is developed which allows the calculation of the venturi scrubber at operating conditions with a non-uniform droplet distribution. The scrubber geometry is also taken into account. A venturi scrubber was developed on the basis of this new model. Its energy consumption is significantly lower than the well-Known optimum characteristic of Wicke and Holzer. For ideal operating conditions, a new optimum characteristic is given which should be the aim of future optimizations.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120125
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Mass transfer and chemical reaction in fluid two-phase systemsPresented in part at the 21th meeting of the Dechema-Arbeitsausschuß “Technische Reaktionen” together with the GVC-Fachausschuß “Technische Reaktionsführung” in Aronoldsheim/Taunus, 10-11th February 1982. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 195-199 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Steady-state concentrations of the transferred reactant in the bulk phase and the non-flowing diffusion boundary layer of an isothermal, isobaric two-phase reactor with an irreversible first-order reaction and constant composition of one phase.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120126
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Model concept of floc disintegration in centrifugal fields (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 200-204 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model of floc destruction resulting form mass forces in a centrifugal field is postulated and its validity examined. This model is to be regarded as a supplement to the existing shear-loading disagglomeration models. In order to verify this additional floc disintegration mechanism, appropriate investigations were carried out with flocculated suspensions of silica and Hamburg dock sludge. As a result, in addition to floc disintegration by shear forces within a turbulent flow and in the centrifuge inlet, the existence of another mechanism was demonstrated. This consists in the floc destruction in a centrifugal field where particles in excess of a certain size, or specifically heavier components, are preferentially torn out of the floc. This floc disintegration by mass forces can lead to a classification effect in centrifuges which also subject the flocs to instant high centrifugal forces.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120127
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Dispersion behaviour of droplets in circular loop reactors (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 205-212 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A circular loop reactor was built for application to a heterogeneous liquid-liquid reaction. In order to investigate the dispersion behaviour of droplets in the reactor, basic experiments were performed using a number of liquid-liquid dispersions. Droplets discharged form the impeller region were found to grow due to coalescence in the circulation region. Mean droplet diameter decreased exponentially with elapsing time. An expression correlating the steady-state mean droplet diameter with the operating conditions was derived. Moreover, the transition time required for the droplet diameter to reach the equilibrium value was determined and correlated with the operating conditions.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120128
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Measurement of aeration capacity of fermenters (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 213-217 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Important aspects of K1a measurement in agitated aerated vessels are briefly characterized from the standpoint of reliability of the measured data. An analysis of the shortcomings of dynamic methods for measuring the K1a is given. A new modification of the dynamic method is proposed, which excludes these inadequacies through a special experimental arrangement. This was verified by comparing the data with those obtained by an independent steady-state method. The new method can serve as a standard of reference, suitable for testing newly developed methods for K1a measurement. The initial response method was tested in this way in non-coalescent liquids, and shown to lead to errors of the order of hundreds of percent. K1a values obtained with the initial response method were found to depend strongly on the probe's location in the vessel.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120129
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    A new model of the effect of stirring intensity on the rate of secondary nucleationPaper presented at the Anual Meeting of the “GVC-Fachausschuß Kristallisation”, The Hague, March 10 to 12, 1986. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 137-146 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Secondary nucleation in industrial crystallizers depends on both supersaturation and mechanical stress by stirring. Most models which consider mechanical stress assume that nucleation is proprotional to the energy transferred to the crystals during collisions. This is not based on any physical relationship and, in addition, the models do not satisfactorily reproduce the experimental results. Own model, based on the theory of Hertz/Huber, which accounts for the stress of the crystals caused by impact, gave better results. This well-known and proven theory allows the calculation of the volume abraded during collisions between crystals and stirrer or walls. Introducing a nucleate efficienncy, the effect of mechanical stress on the rate of secondary nucleation, due to stirring intensity and crystallizer size, can be determined.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120119
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    A new particle size effect (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 147-154 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The sintering effect of highly dispersed metals is the reason for the following phenomena: thermal deactivation, particle size effect, separable or non-separable kinetics and the isokinetic relationship ( = compensation effect). A comparison of these phenomena reveals a contradiction which can be reconciled by a new particle size effect. This effect is characterized in the following way: The dependence of specific activity on particle size is always connected with a variation of the activation energy, caused by the particle size distribution. Therefore, this effect is referred to as the partical size and distribution effect, P.S.D.E. This new concept describes all the observed phenomena of the conventional partical size effect. Moreover, it is consistent with similar effects such as non-separable kinetics and the isokinetic relationship. In consequence, the method of isothermal measurement of specific activity is inadequate.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120120
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Porosity and permeametry at sub-atmospheric pressures (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 255-261 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Carman-Kozeny equation is applicable in the viscous flow regime but, as the powder becomes finer, this equation fails. The controlling factor is the ratio of the hydraulic diameter to the mean free path of gas molecules (rH/λ) and, as this approaches unity, “slip flow” occurs. This effect increases with (a) increasing fineness, i.e. rH reduced, (b) decreasing porosity, i.e. rH reduced, and (c) decreasing pressure, i.e. λ increased. In order to account for the enhanced flow arising as a result of this failure, a second term is introduced into the equation and this includes an unknown “constant” (δK0/K), the coefficient of slip. It was considered probable that this so-called constant was a function of (rH/λ), and an attempt was made to investigate this relationship.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120135
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Streamline-upwind/Petrov-galerkin finite element methods in polymer processing (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 269-273 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120137
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Characterization of mixing and residence time distributions in nozzle-type reactors (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 262-269 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies of flow characteristics and residence time distribution, (RTD), have been undertaken in a range of geometrically similar, laboratory nozzle-type reactors. High-speed cine-photography was employed to record the complex phenomena of liquid mixing in the reactor and also to record on film the colour of an injected tracer solution leaving in the effluent. A novel atomic absorption spectrophotometric (AAS) technique was applied to transform the results of the latter film into response curves. This technique provide detailed quantitative data on the residence time distributions (RTD) for different feed rates. A multiparameter model, comprising a network of CSTR's and plug flows, was developed to simulate the experimental response data. Good agreement was obtained between model predictions and experimental results. The experimental technique and theoretical approach are recommended for analyzing the flow patterns and mixing mechanisms in such reactors.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Fluid dynamic description of jet-loop reactors in multiphase operationModified version of a paper presented by K.H. Tebel at the “Jahrestreffen der Verfahrens-Ingenieure”, Strasbourg, September 17 to 19, 1986. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 274-280 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A superposition of simple physical equations allows a satisfactory, comprehensive fluid dynamic description of jet-loop reactors in multiphase operation up to a dispersed phase hold-up of 15%. In the case of higher concentrations, there are further interactions which are not yet included in the model description. Apart from the drag coefficient of the single-phase jet loop, information on the particle swarm behaviour, i.e. on the slip velocity of the dispersed phase is required. Explicit formulation of the influence of the relevant geometrical parameters permits a reliable scale-up without additional adaptation parameters.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120138
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Vapour-liquid equilibria of hydrogen/coal liquid and methane/coal liquid systems at elevated temperatures and pressures (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 280-288 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A cubic equation of state is modified in such a way that prediction of PVT data from 40 model compounds, typical of coal oil, becomes possible with an absolute mean deviation of less than 2% for saturated liquid volumes and vapour pressures 〉 1 bar. Additional correlations for binary interaction parameters are obtained by an optimization procedure using vapour-liquid euilibrium (VLE) data from known heavy hydrocarbon liquid/light gas systems. When the modified equation is applied to coal-derived liquids, only specific gravity and boiling analysis data of the coal liquids are required, primarily in order to determine the equation-of-state parameters. The proposed equation is shown to allow a good prediction of VLE data for systems consisting of wide-boiling-range coal oils and light gases. Experimental values were obtained at elevated temperatures and pressures with a circulation flow apparatus.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120139
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Heat transfer enhancement in fin-plate heat exchangers by wing type vortex generatorsDedicated to Professor Dr. Klaus Gersten on the occasion of his birthday. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 288-294 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Heat transfer and fluid mechanical data were computed for laminar channel flows containing strong longitudinal vortex pairs. The strong vortices are generated by thin delta wings and delta winglet pairs of low aspect ratios and large angles of attack. These wings are attached to the channel walls. The data show that longitudinal vortices cause high local peaks in heat transfer and marked increases in the overall channel heat transfer. These increases occur over a wide region of channel wall, compared to the vortex generating wing area. The results are of special interest for compact heat exchangers. The heat transfer enhancement allows a considerable reduction in the heat transfer area which, in turn, reduces the manufacturing and operating costs.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120140
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Particle collection in small laboratory cyclones as a basis for the design of large-scale cyclonesPaper presented by H. Büttner at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg September 30 to October 2, 1987. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 295-301 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Grade efficiencies must be measured in order to characterize particle collection in cyclones. For real, irregularly shaped partcles, the grade efficiencies depend on the shape and orientation of the particles and the flow around them. Therefore, the collection characteristics of cyclones should be defined in relation to spherical particles. Deviations occurring on the use of real, irregularly shaped dusts can then be attributed to a material influence. A fast and accurate measuring technique to determine the collection characteristic for spherical particles is described, followed by the presentation of results of extensive investigations on small model cyclones. A similarity relationship is presented. The validity of this relationship was confirmed by investigations with similar, larger cyclones.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120141
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Reversible absorption of nitric oxide in low volatile organic liquids containing cupric halides (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 33-37 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The absorption of nitric oxide (NO) in phosphoric acid esters and polyethylene glycol ethers which contain cupric halides has been investigated. Due to high solubility of cupric halides and high equilibrium constants of formed nitrosyl complexes, the effective solubility of nitric oxide can be enhanced to about 100-fold its solubility in the salt-free organic liquid which itself amounts to only about 5-fold the NO-solubility in water. Calculations taking into account flue gas conditions indicate that the required gas-liquid ratio in industrial absorption processes will lie in the normal range of flue gas scrubbing processes, namely in the region of 400:1 to 1000:1 in volume. Thus, such a reversible absorption process could a viable alternative to SCR-processes in flue gas denitrification.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120107
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Effects of pretreatments on semi-continuous anaerobic digestion of wheat straw (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 96-102 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of alkali treatment, nitrogen supplement and hydraulic retention time on methane production rate from semi-continuous anaerobic digestion of 5% wheat straw-water mixtures were investigated. The experiments were carried out in laboratory scale fermenters, fed with 1 1 of basic, alkali treated and nitrogen supplemented 5% wheat straw-water mixtures, respectively, and maintained at 55 °C. Digestion experiments were performed for hydraulic retention times of 8, 10 and 15 days. The amount and composition of produced gas were measured until steady state was attained in each run. The steady-state methane production rates were found to increase with hydraulic retention time and with the type of slurry in the following order; basic, nitrogen supplemented and alkali treated slurry. Data obtained from the experiments were employed to determine the kinetics of methane production from anaerobic digestion of wheat straw, for the assessment of pretreatment effects on process kinetics. The predicted methane production rates were found to be in a reasonably good agreement with the measurements.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Increase in viscosity and its influence on polymerization processesDedicated to Prof. Dr. Heinz Gerrens on the occasion of his 65th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 71-87 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In the course of polymerization in homogeneous systems, the viscosity of the reaction mass increases by several orders of magnitude. The viscosity increase is affected by reaction conditions, concentration and properties of the formed polymer. Empirical correlations for homogeneous and heterogeneous polymerizations are given. Viscosity significantly affects the polymerization kinetics as well as heat, mass and momentum balances of the polymerization reactor. The influence of viscosity and its increase on conductive heat transfer, stirrer power input and cooling capacity, molecular diffusion and mass transfer coefficients, mixing time and residence time distribution in homogeneous and heterogeneous polymerizations in stirred tank and tubular reactors is reviewed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120112
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Advances in modelling and design of multitubular fixed- bed reactorsI. Description of Interaction Between Reactants and Coolant (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 113-130 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Starting from the review of current industrial designs, the present paper analyzes thermal interaction between reactants and coolant in multitubular fixed-bed reactors. The interaction can be described quantitatively in terms of parameters characterizing transport processes both on the tube side and in the intertubular space. The study provides a detailed discussion of existing methods and correlations used for the evaluation of these parameters. The methods presented here can be considered as a basis for the development of a more comprehensive approach to the modeling and design of multitubular catalytic reactors.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120117
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Determination of size and stress intensity factors for leaks in nozzle attachmentsPaper presented by G. Wiedemann at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 131-137 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The prediction of leak areas in pressure vessels is an important objective in the safety analysis of chemical plants. Using suitable design rules, a leak-before-break behaviour can be achieved. This contribution outlines a procedure for the leak-before-break design of nozzle attachments and the determination of the size of the corresponding opening area. In addition, K1-factors and leak areas for a number of nozzle geometries have been calculated and plotted.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120118
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    The contradiction in the theory of desorption phenomena: A new interpretation of the classical concept for its avoidance (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 218-225 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Most chemical engineers presently accept that the mass transfer rate in desorption from the solid to the gas phase or from the liquid to the gas phase is accelerated with increasing temperature in the liquid or the solid phase, or increasing partial pressure of inert gas in the gas phase, and/or decreasing total system pressure in the gas phase. Nevertheless, many reports about such mass transfer are still based on the former concept, which completely contradicts the actual phenomena mentioned above. Here, we discuss the contradiction and suggest a way of resolving it in terms of diffusion theory.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120130
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Influence of turbulence on transient premixed flame propagation inside closed vessels (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 226-233 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The explosion behaviour of CH4/air mixtures inside a closed 0.065 m3 spherical and a 1 m3 cylindrical vessel was investigated to determine the effect of turbulence on the structure and propagation rate of transient turbulent flames for different initial turbulence levels generated by 4 ventilators installed inside the equipment. Laser-Doppler and hot wire anemometry were used to measure the turbulent motion. It was found that fairly uniform turbulence could be achieved in the central zones of the vessels and that the RMS-values of flow velocity were proportional to the ventilator speed. The evaluation of burning velocity from the pressure/time records showed that, starting from an initial burning velocity which depends on the initial turbulence level, the flame accelerates as a result of pressure, temperature and turbulence effects. Maximum burning velocity coincides with the inflexion point of the pressure/time curve, and is followed by a rapid deceleration of the flame front. A linear relationship between burning velocity and measured RMS-velocity is recognized in the observed range of RMS-values.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120131
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Reduction of energy requirements in distillationExtended version of a paper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 163-169 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Distillation has been, up to now, the standard method for separating fluid mixtures in the process industry and the consensus is that it will remain so for years to come. The only disadvantage of distillation is its high energy requirement. In the following, it will be demonstrated on the example of an ideal ternary mixture, how the energy requirement of distillation process can be reduced. Very effective are some modifications of single columns, optimization of column sequences and direct or indirect column coupling. It will be shown that, just by column coupling, the energy requirement can be reduced to a third.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120122
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Effects of turbulence on heat and mass transfer in stagnation flowsPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Freiburg, September 30 to October 2, 1987.Dedicated to Professor Dr. Josef Kestin on the occasion of his 75th birthday (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 176-187 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of turbulence on local heat and mass transfer is systematically analyzed. Essential prerequisite is the availability of measurement methods, based on convective mass transfer, which allow the visualization of heat and mass transfer distributions. The results show that, even at low turbulence intensities, the flow and transport phenomena are decisively influenced by the specific design of turbulence grids and the orientation of the grid wires with respect to the stagnation line. Thereby, two different flow mechanisms occur which may interact. The anisotropy of grid turbulence leads to the “wire-gap effect” depending on the actual position of the grid wires in relation to the stagnation line. The other mechanism is based on the wavy wake velocity distribution behind screens and grid which, in conjunction with the centrifugal instability of stagnation flows, may lead to longitudinal vortices. The results indicate why turbulence has not been sufficiently considered in the available (semi-) empirical correlations. Information needed for an accurate prediction of heat and mass transfer in turbulence flows is discussed.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120124
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Mallomonas alphaphora (Chrysophyceae), a new species from Western Australia (1989)
    Springer
    Plant systematics and evolution 164 (1989), S. 209-214 
    Details
    ISSN: 1615-6110
    Keywords: Algae ; Chrysophyceae (Synurophyceae) ; Mallomonadaceae ; Mallomonas alphaphora ; Electron microscopy ; phytoplankton ; scale-bearing flagellate ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new species ofMallomonas, M. alphaphora (Chrysophyceae), was found in freshwater ponds in the Perth region, Western Australia. It is distinguished from other species ofMallomonas by its very distinctive scale and bristle morphology and is placed in a new section,Alphaphorae, of the genusMallomonas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00940438
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Immature rat epididymal epithelial cells grown in static primary monolayer culture on permeable supports (1989)
    Springer
    Cell & tissue research 256 (1989), S. 573-580 
    Details
    ISSN: 1432-0878
    Keywords: Epididymis ; Epithelium ; Monolayer culture ; Histochemistry ; Electron microscopy ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary N-acetylglucosaminidase (NAG), acid phosphatase (ACP) and alkaline phosphatase (AKP) were localised histochemically in fixed cells from the 37-day-old rat epididymis grown in static monolayer culture for 2–8 days. ACP and NAG were cytosolic enzymes found in perinuclear positions, whereas staining of AKP was consistent with a membranous position. These enzymes were also examined in frozen tissue sections of the epididymis, from rats of the equivalent age, where NAG had intense activity in both supra- and infra-nuclear cytoplasm and ACP was more active apically. For the first time AKP was localised along basolateral membranes of the epithelium and in the lumen of the mid-caput region. The monolayer in culture was of principal cells only and they maintained their polarity and ultrastructural characteristics, but the height of the cells was reduced compared to that obtained in situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225606
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Two types of mammosomatotropes in mouse adenohypophysis (1989)
    Springer
    Cell & tissue research 256 (1989), S. 645-648 
    Details
    ISSN: 1432-0878
    Keywords: Mammosomatotropes ; Adenohypophysis ; Electron microscopy ; Immunohistochemistry ; Mouse (SMA)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Two types of mammosomatotropes (MS), the small-granule and vesicle-granule MS, were detected in mouse adenohypophysis by electron microscopy and immunohistochemistry. Both cell-types were immunoreactive to prolactin (PRL) and growth hormone (GH) antisera. The small-granule MS contained small, round, solid secretory granules about 100 nm in diameter, and were smaller than the classical GH and PRL cell-types. The vesicle-granule MS contained secretory granules like cored vesicles, and were larger than classical GH and PRL cells. Small-granule MS were immunoreactive to both PRL and GH antisera in the same region of the cell cytoplasm; the vesicle-granule MS, however, were immunoreactive to only PRL antiserum in most cytoplasmic areas, and a positive response to both PRL and GH antisera was confined to only certain small areas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225615
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Localization of cholesterol in the colonic epithelium of the guinea pig: regional differences and functional implications (1989)
    Springer
    Cell & tissue research 258 (1989), S. 339-347 
    Details
    ISSN: 1432-0878
    Keywords: Proximal colon ; Distal colon ; Cholesterol ; Filipin ; Freeze-fracture ; Electron microscopy ; Guinea Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary It is generally accepted that variations in membrane cholesterol content affect the fluidity of the bilayer, thus altering its permeability. In the biological membranes, in physiological conditions, a high cholesterol content rigidifies the bilayer decreasing its permeability, a lower cholesterol content induces the opposite effect by increasing the permeability. Since differences in the epithelial permeability for short chain fatty acids have previously been demonstrated in the proximal and distal colon of the guinea pig, these two regions were investigated to establish whether differences in membrane cholesterol content of the absorbing cells can be demonstrated. Freeze-fracture replicas of filipin-treated colonic tissue were used. The results show that in the proximal colon the density of filipin cholesterol complexes located on the luminal plasma membrane of the columnar absorbing cells was significantly higher (about twice) than in the distal colon. Therefore the lower amount of cholesterol present in the membrane of the absorbing cells in the distal colon indicates a greater fluidity of the membranes of the epithelial cells in this region. Such fluidity could be correlated to the higher absorption rates of shortchain fatty acids characteristic of this region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239454
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Quantitative electron microscopy of endocrine cells in oxyntic mucosa of normal human stomach (1989)
    Springer
    Cell & tissue research 255 (1989), S. 41-48 
    Details
    ISSN: 1432-0878
    Keywords: Stomach ; Endocrine cells ; Electron microscopy ; Morphometry ; Man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural morphometric study of the endocrine cells of the oxyntic mucosa of the stomach in gastric biopsies collected from five male and five female healthy volunteers aged 19–31 was performed. No sex-related differences were disclosed. Endocrine cells accounted for 1.2±0.4% of the epithelial volume and 0.9±0.4% of the mucosal volume, i.e., including the lamina propria. After classification of the specific endocrine cell types according to the ultrastructural morphology of secretory granules, the volume densities of ECL, P and D cells (30±9%, 24±7%, and 22±4% of the entire endocrine cell mass, respectively) were higher than those of other endocrine cell types. In particular, EC cells contributed less than 10% and X cells represented a very low proportion of the total cells. Non-granulated profiles of cells which in all other respects appeared to be endocrine were also found with a volume density of 8±4%. D cells were distinguished by the high fraction of cytoplasm occupied by secretory granules (31±5%). Subdivision of the whole mucosa into four horizontal segments revealed the endocrine cells to be mostly distributed in the three lower, with virtually no endocrine cells in the superficial segment. The quantitative ultrastructural analysis of the endocrine cell population of the normal human oxyntic mucosa provided by this study may allow a better evaluation of physiological and pharmacological variations of the endocrine cell population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229064
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Gestational changes in hamster adrenal cortex: Morphometric and ultrastructural stereologic studies (1989)
    Springer
    Cell & tissue research 256 (1989), S. 241-246 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Pregnancy ; Electron microscopy ; Stereology ; Golden hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the hamster, the weight of the adrenal glands increases during the course of gestation, with the highest value at day 5. In comparison to non-pregnant control animals, there were no changes in the volume of the zona glomerulosa (ZG) and zona fasciculata (ZF), while the volume of the zona reticularis (ZR) increased notably. The average volume of ZG-cells rose at day 5 of pregnancy and thereafter gradually decreased to that of control hamsters. A marked drop in the volume of ZF-cells was seen at days 5 and 10 of pregnancy, whereas at day 15 the cells were larger than in controls. At day 5 of pregnancy, a conspicuous increase in the cell volume was found in ZR, followed by lower values at day 10 and again higher than in control hamsters at day 15. The total number of parenchymal cells in hamster adrenal cortex increased at day 10 of gestation, then underwent a marked decrease, reaching the control value at the final day of pregnancy; this drop was mainly due to a reduction in the number of ZF-cells. The changes in the cell volume were paralleled by rather proportional changes in the volume of the mitochondrial compartment and in the quantity of smooth endoplasmic reticulum. The volume of the lipid-droplet compartment significantly rose in the course of gestation in both ZF- and ZR-cells. The cortisol output by adrenal homogenates gradually decreased during pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218881
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Glomerular podocytes in cultured rat kidney slices (1989)
    Springer
    Cell & tissue research 256 (1989), S. 419-429 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Glomerulus ; Podocytes ; Tissue culture ; Electron microscopy ; Morphometry ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of rat glomerular epithelial cells (podocytes) in kidney slices in vitro was examined using qualitative and quantitative electron microscopy. The kidney slices were cultured in Medium 199 with Hanks' salts in a 5% CO2/95% O2 environment for up to 14 days. Few changes in podocyte ultrastructure occurred in the first 12 h of culture, but by 24 h cell bodies were rounded, microvilli were present on all podocyte surfaces, and some foot processes had been replaced by flattened expanses of cytoplasm. These changes were more pronounced by 3 days, when some podocytes had developed pseudopodal extensions and appeared to be migrating from glomeruli onto the slice surface. Podocytes could still be identified after 8, 10 and 14 days of culture, although relatively few glomeruli remained at 14 days. Morphometric methods were used to analyse podocyte shape, volume and surface area during the first 4 days of culture. The most significant change involved loss of foot processes: the number of filtration slits per 100 μm of basement membrane decreased from 211.8 ± 15.0 (mean ± SD) at the commencement of culture, to 55.3 ± 22.6 after 2 days (P 〈 0.001). These data provide baseline information for in vitro studies on the effects of nephrotoxins on podocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218900
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Nasal lymphoid tissue in the rat (1989)
    Springer
    Cell & tissue research 255 (1989), S. 193-198 
    Details
    ISSN: 1432-0878
    Keywords: Mucosa-associated lymphoid tissue ; Nose ; Lymphoepithelium ; Electron microscopy ; Immunohisto-chemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure and organization of paired lymphoid tissue in the nasal mucosa, situated in the transitional zone on both sides of the septal opening to the pharyngeal duct, of conventionally-housed rats was examined by light microscopy and scanning and transmission electron microscopy. Each lymphoid structure consisted of follicles containing T- and B-cell areas, and was covered with specialized epithelium. This epithelium consisted of cuboidal ciliated cells with oval nuclei parallel to the basal lamina. Goblet cells were sparse. Occasionally, islands of microvilli-bearing cells (so called membraneous or M cells) covered the lymphoid structures. M Cells were also found as single cells among the ciliated cells. The morphological characteristics and the particular localization justify the conclusion that the nasal lymphoid tissue described belongs to the mucosa-associated lymphoid tissue. It is therefore suggested that this nasal structure be designated nasal lymphoid tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229081
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Immunocytochemical and ultrastructural studies on allografts of the pituitary neurointermediate lobe in the third cerebral ventricle of the rat (1989)
    Springer
    Cell & tissue research 255 (1989), S. 393-404 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Neural lobe ; Intermediate lobe ; Intraventricular graft ; Immunocytochemistry ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Neurointermediate lobes from adult or 10-dayold rats were implanted by a stereotaxic procedure into the third ventricle of adult male rats, in an area close to the paraventricular nucleus. They were examined, using immunocytochemical and ultrastructural techniques, at times ranging from 1 week to 8 months. All grafts were recovered in a healthy condition although some rejection of the tissue was detected at the 1and 2-week stages. In the neural lobe, clusters of pituicytes were scattered among the loose network of capillaries, most of which had a fenestrated endothelium. The intermediate lobe remained organized in compact avascular lobules. Axons similar to those projecting into the neurointermediate lobe in situ, but also axons of other types (e.g., somatostatinergic, enkephalinergic) penetrated the grafts. Synapses with melanotrophic cells in the intermediate lobe and neurohaemal contacts in the neural lobe were frequent from 2 1/2 months after transplantation. Immunocytochemical and ultrastructural characteristics indicated intense secretory stimulation of the melanotrophic cells in the early stages. All cells enclosed in a same glandular lobule reacted in a similar manner. In later stages, when re-innervation occurred, the cells recovered their initial characteristics. The overall effect of the re-innervation of the intermediate lobe grafted in this location is inhibitory, as in the lobe in situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224123
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Vasoactive intestinal polypeptide (VIP)- and neuropeptide Y (NPY)-containing nerve fibres in the penile cavernous tissue of green monkeys (Cercopithecus aethiops) (1989)
    Springer
    Cell & tissue research 256 (1989), S. 529-541 
    Details
    ISSN: 1432-0878
    Keywords: Penile erection ; Electron microscopy ; Immunohisto(cyto)chemistry ; Vasoactive intestinal polypeptide (VIP) ; Neuropeptide Y (NPY) ; Cercopithecus aethiops (Primates)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cavernous body of green monkeys contains many unmyelinated and few myelinated axons. The unmyelinated axons form terminals in the adventitia of the arteries, between trabecular muscle cells, in the interstitium, and close to endothelium cells of the sinuses. All terminals displayed predominantly “small clear vesicles” and very few “large granular vesicles”; “small granular vesicles” were not seen. However, in rabbit penises, terminals with many large granular vesicles are prominent. Immunohistochemistry (PAP technique) showed a dense network of VIP- and NPY-reactive fibres around the arteries and around trabecular muscles. The density of nerve fibres was particularly high around the subendothelial cushions of the helicine arteries. Double staining for NPY and VIP revealed that both peptides were colocalized. Immunocytochemistry (preembedding PAP technique) showed VIP- and NPY-reactivity in terminals with small clear vesicles; the reaction product was bound to the cytoplasmic face of different membrane types. Although the intracellular localization of the reaction product is probably due to artefactual displacement during preparation, the uniformity of the terminals questions the view that large and small granular vesicles in all species characterize peptidergic and noradrenergic terminals, respectively. The essential findings can be summarized as (1) a high degree of uniformity of nerve terminals, (2) colocalization of VIP and NPY, (3) heavy innervation of the subendothelial cushions of the helicine arteries, and (4) possible innervation of endothelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225601
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Granulated peripolar epithelial cells in the renal corpuscle of marine elasmobranch fish (1989)
    Springer
    Cell & tissue research 257 (1989), S. 61-67 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Peripolar cells ; Renal corpuscle ; Electron microscopy ; Raja erinacea, Mustelus canis, Rhinoptera bonasus, Sphryna lewini, Rhizoprionodon terraenovae, Squalus acanthias (Elasmobranchii)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Granulated epithelial cells at the vascular pole of the renal corpuscle, peripolar cells, have been found in the kidneys of five species of elasmobranchs, the little skate (Raja erinaced), the smooth dogfish shark (Mustelus canis), the Atlantic sharpnose shark (Rhizoprionodon terraenovae), the scalloped hammerhead shark (Sphryna lewini), and the cow-nosed ray (Rhinoptera bonasus). In a sixth elasmobranch, the spiny dogfish shark (Squalus acanthias), the peripolar cells could not be identified among numerous other granulated epithelial cells. The peripolar cells are located at the transition between the parietal epithelium of Bowman's capsule and the visceral epithelium (podocytes) of the glomerulus, thus forming a cuff-like arrangement surrounding the hilar vessels of the renal corpuscle. These cells may have granules and/or vacuoles. Electron microscopy shows that the granules are membrane-bounded, and contain either a homogeneous material or a paracrystalline structure with a repeating period of about 18 nm. The vacuoles are electron lucent or may contain remnants of a granule. These epithelial cells lie close to the granulated cells of the glomerular afferent arteriole. They correspond to the granular peripolar cells of the mammalian, avian and amphibian kidney. The present study is the first reported occurrence of peripolar cells in a marine organism or in either bony or cartilagenous fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221634
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Electron-microscopic study on the anterior pituitary gland of spontaneous dwarf rats (1989)
    Springer
    Cell & tissue research 258 (1989), S. 477-482 
    Details
    ISSN: 1432-0878
    Keywords: Anterior pituitary gland ; Electron microscopy ; Growth hormone ; Spontaneous dwarf rats (dr/dr)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The spontaneous dwarf rat is a novel experimental model animal on the study of pituitary dwarfism. The fine structure of the anterior pituitary cells was studied in the immature and mature dwarf rats. Pituitary glands were removed from 5-, 10-, 20-day-old immature dwarfs, adult (45 days-16 weeks) dwarfs and normal 3-month-old rats and processed for electron-microscopic observation. In the control animals, growth hormone cells were readily identified by their ultrastructural characteristics, such as the presence of numerous electron-dense secretory granules, 300–350 nm in diameter, well developed rough endoplasmic reticulum and a prominent Golgi complex. In contrast, growth hormone cells were not found in the anterior pituitary gland of the spontaneous dwarf rat at any age examined. Other pituitary cell types, i.e., luteinizing hormone/ follicle stimulating hormone, thyroid stimulating hormone, adrenocorticotropic hormone and prolactin cells, appeared similar in their fine structure to those found in the control rats. In the pituitary gland of dwarf rats, a number of polygonal cells were observed either with no or relatively few secretory granules. The rough endoplasmic reticulum was arranged in parallel cisternae and the Golgi complex was generally prominent in these cells. In addition, many were found to have abundant lysosomes. A few minute secretory granules were occasionally observed; however, the immunogold technique failed to localize growth hormone or prolactin in the granules. The nature of these cells remained obscure in this study. Since their incidence and fine structural features, other than the secretory granules, were quite similar to those of the growth hormone cells in normal rats, we postulate that these cells are dysfunctional growth hormone cells. These results suggest that the cause of the growth impairment in the spontaneous dwarf rat is due to a defect in the functional growth hormone cells in the pituitary gland, and since other pituitary cell types appeared normal, the disorder seems to be analogous to the isolated growth hormone deficiency in the human.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218859
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Light- and electron-microscopic investigation of the rat subcommissural organ grafted under the kidney capsule, with particular reference to immunocytochemistry and lectin histochemistry (1989)
    Springer
    Cell & tissue research 258 (1989), S. 499-514 
    Details
    ISSN: 1432-0878
    Keywords: Subcommissural organ ; Secretory activity, neural control ; Transplantation ; Long-spacing collagen ; Immunocytochemistry ; Molecular markers (neuronal, glial) ; Electron microscopy ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary There is increasing evidence that, in the rat, a serotonin-mediated neural input may have an inhibitory influence on the secretory activity of the subcommissural organ (SCO). In the present investigation the rat SCO was studied 7, 30 and 90 days after transplantation under the kidney capsule, an area devoid of local serotonin-containing nerves. The grafted tissue was examined by use of immunocytochemistry employing a series of primary antisera, lectin histochemistry and transmission electron microscopy. The grafted SCO survived transplantation and contained, in addition to secretory ependymal and hypendymal SCO-cells, also elements immunoreactive with antisera against glial fibrillary acidic protein or S-100 protein. In transplants, SCO-cells produced a material displaying the characteristic immunocytochemical and lectin-binding properties of SCO-cells observed under in-situ conditions. The ependymal cells lined 1–3 small cavities, which contained secretory material. A fully developed structural equivalent of Reissner's fiber was, however, never found. The immunocytochemical and ultrastructural study of the grafted SCO showed an absence of nerve fibers within the graft and suggested a state of enhanced secretory activity. A network of protruding basal lamina structures connected the secretory cells to the newly formed capillaries revascularizing the SCO. One week after transplantation, long-spacing collagen started to appear in expanded areas of such laminar networks and also in the perivascular space. It is suggested (i) that the formation of long-spacing forms of collagen is triggered by factors provided by the SCO-secretory cells, and (ii) that secretory material of the ependymal and hypendymal cells may reach the reticular extensions of the basal lamina. In contrast to the SCO in situ, the grafted SCO-cells showed a positive immunoreaction for neuron-specific enolase. They became surrounded by a S-100-immunoreactive glial sheath that separated them from other transplanted cell types and the adjacent kidney tissue of the host.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218862
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Leakage rates of refrigerants through cracksPaper presented by F. Westphal at the European Two-Phase Flow Group Meeting, Université Catholique de Louvain, Brussels, May 30 to June 1, 1988. (1989)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 12 (1989), S. 301-308 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An independent preliminary mechanistic prediction method for leakage rates through small slit-shaped through-wall cracks, based on coupled pressure drop and (critical) mass flux calculation is presented. The predictions are verified against initially subcooled liquid refrigerants and water data collected during experiments in real and model cracks in a wide range of parameters. The achieved accuracy of prediction is already comparable to that of the experimental results. Further model modifications are put forward.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270120142
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...