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  • 1
    Electronic Resource
    Electronic Resource
    Klinik und Therapie des Merkelzelltumors (1988)
    Springer
    Langenbeck's archives of surgery 373 (1988), S. 173-181 
    Details
    ISSN: 1435-2451
    Keywords: Merkel cell tumor ; Trabecular carcinoma ; Neuroendocrine tumor ; Neuron-specific enolase ; Cytokeratins ; Clinical findings in 339 cases ; Surgery ; Radiotherapy ; Chemotherapy ; Local recurrence ; Lymphatic metastasis ; Hematogenous metastasis ; Prognosis ; Follow-up
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wird über vier Fälle eines Merkelzelltumors mit unterschiedlichem klinischen Verlauf und Lokalisation im Gesicht und am Stamm berichtet. Bezüglich der Klinik wurden 339 Fälle eines Merkelzelltumors aus der Literatur ausgewertet. Beim Merkelzelltumor handelt es sich um einen von den Merkelschen Zellen ausgehenden neuroendokrinen Hauttumor. Er findet sich zu 47% im Kopf-Halsbereich, hat eine durchschnittliche Größe von 25 mm, liegt typischerweise über dem Hautniveau und zeichnet sich klinisch durch seine rötlich-livide Farbe aus. Aufgrund der Metastasierung und des infiltrativen Wachstums ist er als maligne einzuordnen. In 27% bestehen Lymphknotenmetastasen, in 51 % kommt es zu Lokalrezidiven und in 32% treten Fernmetastasen auf. Die Therapie der Wahl besteht in einer frühzeitigen Excision mit einem Sicherheitsabstand, wie er bei malignen Hauttumoren üblich ist. Eine Strahlensensibilität liegt vor; ob auch eine chemotherapeutische Beeinflußbarkeit besteht, ist jedoch nicht sicher.
    Notes: Summary Four cases of Merkel cell tumor located in the face or on the trunk are presented. In a literature review 339 cases were found and analysed. The Merkel cell tumor is a neuroendocrine tumor of the skin derived from the Merkel cells. It is located most often in the face and neck area. Typically, it is an exophytic node, has a red-blue color and measures 25 mm in diameter on the average. Since it is metastasizing it is a malignant tumor. Regional node metastases were found in 27%, local recurrences occur in 51%, and distant metastases were seen in 32% of the cases. The best therapy is excision with wide margins as is the rule for a malignant skin tumor. While the tumor reacts to radiotherapy, chemotherapy seems to be of no help.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01274230
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  • 2
    Electronic Resource
    Electronic Resource
    Morphologie und Prognose des folliculären Schilddrüsencarcinoms — Eine klinisch-pathologische und DNS-cytometrische Untersuchung an 95 Tumoren (1987)
    Springer
    Langenbeck's archives of surgery 370 (1987), S. 3-24 
    Details
    ISSN: 1435-2451
    Keywords: Follicular thyroid carcinoma ; Morphology ; Prognosis ; DNA-cytophotometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In einer retrospektiven Studie an 95 folliculären Schilddrüsencarcinomen wurden verschiedene morphologische und klinisch-biologische Parameter auf ihre prognostische Bedeutung geprüft. Das klinische Verhalten der Tumoren wurde vorrangig durch Vorhandensein oder Fehlen einer Kapselbegrenzung bestimmt: Grob invasive Carcinome zeigten sechsfach häufiger einen letalen Verlauf als gekapselte Neoplasien. Ein ungünstigeres Verhalten ergab sich ferner bei Manifestation des Tumors im höheren Lebensalter (Schwellenalter: 52 Jahre) und bei Nachweis einer oxyphilen Differenzierung, weiterhin bei Vorliegen von Lymphknotenmetastasen, einer Halsweichteilinfiltration und - im Fall gekapselter Carcinome - von Fernmetastasen. Dagegen hatten die Faktoren Differenzierungsgrad und Geschlecht keinen signifikanten Einfluß auf die Prognose. Bei 22 Tumoren erfolgten cytophotometrische und flußcytometrische DNS-Bestimmungen. Der diagnostische Nutzen dieser Verfahren war dadurch limitiert, daß an Hand der DNSHistogramme in der Mehrzahl der Carcinome keine eindeutige Dignitätsbeurteilung getroffen werden konnte. Dagegen erwiesen sie sich als brauchbares Instrument für die Prognosebeurteilung individueller grob invasiver Tumoren. Die diagnostische, differentialtherapeutische und prognostische Bedeutung der Befunde sowie deren Relevanz für die Subklassifikation folliculärer Schilddrüsencarcinome wird diskutiert.
    Notes: Summary A retrospective study of 95 follicular thyroid carcinomas was conducted to evaluate the prognostic value of different morphological and clinical features. The biological behaviour of these tumours was primarily influenced by presence or absence of a capsule type of confinement: the frequency of lethal outcome among widely invasive carcinomas was six times higher than among encapsulated neoplasms. Furthermore, dismal prognosis could be demonstrated for tumours occurring in older patients (with a sharp break in the prognosis at the age of 52 years) and for those lesions which displayed oxyphilic metaplasia. The same effect was shown for presence of lymph node metastasis, tumour invasion of the cervical soft tissue and, for the case of encapsulated carcinomas, distant haematogenous spread. Conversely, the degree of differentiation and the patients' sex proved to have no significant influence on prognosis. In 22 carcinomas, cytophotometric and flow-cytometric determinations of DNA values were performed. These procedures revealed to have only limited diagnostic value, since for the majority of the tumours, benignancy or malignancy could not be judged from the DNA histograms. However, DNA measurements proved to contribute valuable information for the prognosis in individual cases of widely invasive follicular carcinomas. The discussion focuses on the diagnostic, therapeutic and prognostic relevance of these findings and on their impact on subclassification of follicular thyroid carcinomas.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01259423
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  • 3
    Electronic Resource
    Electronic Resource
    The effect of processing on rheological and molecular characteristics of a low density polyethylene (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 377-382 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The viscoelastic responses of some molten polymers, and particularly of low density polyethylene (LDPE), are known to vary with processing history. Reasons for the variations include the effects of shear history on morphological states of the polymer, or on its molecular weight parameters. A typical low density polyethylene has been used to test the shear-history dependence concept following a variety of processing steps. The polymer was sheared in single-screw and twin-screw extruders, and in a high speed melter / mixer (Gelimat). Samples also were precipitated from very dilute solutions in trichlorobenzene and in p-xylene. GPC analyses showed that, in general, these procedures did not affect the various moments of molecular weight. An exception was the Gelimat-mixed sample, for which mild reductions in Mn and Mw were noted. In contrast, melt viscosity and elasticity readings, the former from low shear evaluations and the latter from extrudate swelling, were affected by the various procedures. A drop in melt viscosity and in elasticity was observed, being most pronounced for precipitated and twin-screw extruded versions of the LDPE. Reductions also were observed in the specimen sheared in the Gelimat instrument. Following conditioning at the test extrusion temperature (170°C), viscous and elastic responses tended to revert to those of the unsheared control sample, the exception again being the sample sheared in the Gelimat melter / mixer. Of the various mechanisms proposed in the literature to account for transient property changes such as those reported, temporary changes in the degree of chain entanglement appear the most satisfactory explanation. Irreversible alterations in viscoelastic properties may be associated with changes in molecular weights due to processing at high shear.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760330702
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  • 4
    Electronic Resource
    Electronic Resource
    Some effects of irradiation on properties of filled PVC compounds (1994)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 34 (1994), S. 981-985 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Compounds based on poly(vinyl chloride) (PVC), and containing CaCO3 filler and trifunctional acrylic crosslinking agent have been crosslinked by exposure to γ-rays at dosages to 70 kGy. The crosslinking agent was found to be essential for crosslinking to proceed, only minor sensitivity to the irradiation having been found in compounds omitting the chemical. The presence of filler somewhat inhibits crosslink effectiveness, as measured by solvent uptake data. Elastic moduli and elongations at rupture respond to crosslinking processes, the latter being particularly sensitive to the effects of irradiation. The presence of filler was found to raise modulus, while ductilities of compounds were greater than expected, owing to adhesion at polymer/filler interfaces. Favorable acid/base interaction forces appear responsible for the effect. The reduced sensitivity of filled PVC compounds to γ-ray exposure is attributed to polymer immobilization, the consequence of strong interfacial bonding with the filler.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760341206
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  • 5
    Electronic Resource
    Electronic Resource
    Some properties of polyethylene compounds with surface-modified fillers (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 263-269 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The dispersion of variously surface-treated CaCo3 fillers in linear low density polyethylene has been studied, along with mechanical properties of the filled compounds. Microwave plasma discharges were used to modify the filler surfaces. Inverse gas chromatographic analyses showed that plasma treatments could change the dispersive and non-dispersive components of filler surface characteristics. A reduction in these surface energies facilitated the dispersion of the filler in the non-polar polyethylene. Mechanical properties, particularly those at high deformation of the filled plastic, also responded to filler surface treatments, the ductility at failure increasing with a decrease in the filler's surface polarity. For any given elongation at failure, it was found that the amount of filler accommodated by the host polymer was raised by the appropriate surface modification procedure. The work illustrates the important contribution made by interfacial phenomena to various performance aspects of complex polymer systems.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760300503
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  • 6
    Electronic Resource
    Electronic Resource
    New approaches to the processing of rutile-filled polyolefins (1990)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 30 (1990), S. 950-956 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The performance of a fluorocarbon elastomer processing additive in rutile-filled linear low density polyethylene (LLDPE) compounds was evaluated by capillary rheometry, and blown film extrusion. Different compounding sequences were considered and their effects on the performance of the processing additive in the presence of various rutiles examined. Lower apparent melt viscosities and higher shear rates for the onset of melt fracture were observed when using certain surface treated rutiles. The nature of the surface coating applied to rutiles was found to have a great influence on the Theological properties of the filled compounds and on the dispersibility of the solids. The acid-base characteristics of rutiles were determined by inverse gas chromatography techniques, and inherent agglomeration indexes for the pigments were measured by an application of powder rheology principles. It was found that those rutiles with high agglomeration indexes or those with highly basic surfaces interfered the most with the processing additive. Mechanisms by which rutile dispersibility and acid-base character influence the effectiveness of the fluorocarbon elastomer processing additive are discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760301604
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  • 7
    Electronic Resource
    Electronic Resource
    Rheological properties of corona modified cellulose/polyethylene composites (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 1734-1739 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The rheological behavior of wood fiber/polyethylene composites made of corona treated constituents was investigated. Corona treatment of one or both of the constituents resulted in decreased melt viscosities relative to compounds containing untreated materials. The reduction of melt viscosity may originate from low molecular weight moieties formed on the surfaces of both polyethylene and cellulose during corona treatment. These may act as lubricants at interfaces. Also it was found that the corona treatment of fibers leads to higher packing volumes; this may result from a reduction in fiber length when treated fibers are processed under high shear conditions. As a result these fibers perturb the normal flow pattern in the melt to a lesser degree than the longer fibers of untreated cellulose.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760322212
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of polymer structure on the onset of processing defects in linear low density polyethylenes (1991)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 31 (1991), S. 1581-1589 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Linear low density polyethylenes are manufactured by copolymerizing ethylene with 1-alkenes, yielding a linear polyethylene backbone with short side chains. Due to the nature of the catalyst used in the polymerizaton, multimodal branching distributions are typically obtained. In this report, we have investigated the processability of four 1-octene linear low density polyethylenes as a function of the short chain branching distribution. Analytical techniques such as 13C nuclear resonance spectroscopy, size exclusion chromatography, differential scanning calorimetry, and temperature rising elution fractionation, in particular were used to elucidate the molecular structure. Processability measurements were made using various extrusion techniques and dynamic mechanical analyses.It was determined that in the absence of any variations in molecular weight, the polymers with the higher proportions of linear polyethylene showed inferior processability In terms of onset of surface imperfections at lower extrusion rates. Polymers with worse processability characteristics also exhibited higher zero shear viscosities.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760312205
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  • 9
    Electronic Resource
    Electronic Resource
    Mechanical properties of corona-modified cellulose/polyethylene composites (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 343-346 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The effect of corona treating the surfaces of components on tensile properties of wood fiber linear low-density polyethylene composites has been investigated. Corona treatment results in a significant increase in strength properties of the composites. Yield stress increases after treatment of one or both of the composite components. Pronounced improvement in ductility has been observed for composites containing 15 to 30% of the corona modified fiber. Relevant mechanisms involved are discussed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760330606
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  • 10
    Electronic Resource
    Electronic Resource
    Comments on “start up pressure transients in a capillary rheometer” by Savvas G. Hatzikiriakos and John M. Dealy, Polym. Eng. Sci., 34, 493 (1994) (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1481-1481 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760351809
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