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  • 1
    ISSN: 1520-510X
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 2 (1880), S. 115-117 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 143-147 (Oct. 1993), p. 435-440 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0584
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The megakaryocytes of the sternal bone marrow and the thrombocytes of the peripheral blood were examined electronmicroscopically in a case with primary hemorrhagic thrombocythemia. The megakaryocytes show morphological malformations of the platelet demarkation tubuli and of the granulomer. Many platelet demarkation tubuli are swollen in a clublike manner and they show figures which are similar to myelin. In addition to this, a disorder of the co-ordination of the synthesis, of the prospective platelet fields may possibly exist. The disordered thrombocytopoiesis results in qualitative platelet defects associated with anisocytosis, pronounced microcytosis and the formation of atypical granula. The atypical granulomer accounts for 18.6% of the total granulomer. Of these 4.6% are rod-granula, 5.2% are drum-stick granula, 6% are ox-eye-granula, and 2.8% are giant granula with a diameter of 0.3–0.5 μ. The increase of the granulomer-γ and the demonstration of numerous glycogen-containing platelets indicate an increase of the number of juvenile platelets. The suspicion, which has been mentioned clinically, that the signs of polycythemia had been added to the symptoms of a primary hemorrhagic thrombocythemia can be confirmed by the electronmicroscopical findings in the megakaryocytes.
    Notes: Zusammenfassung Die Megakaryozyten des Sternalmarkes und die Thrombozyten des peripheren Blutes wurden bei einem Fall von primär hämorrhagischer Thrombozythämie elektronenmikroskopisch untersucht. In den Megakaryozyten bestehen morphologische Fehlbildungen an den Plättchendemarkationstubuli und am Granulomer. Viele Plättchendemarkationstubuli sind keulenförmig aufgetrieben und zeigen myelinähnliche Figuren. Zusätzlich besteht möglicherweise eine Störung in der Koordination der Synthese der prospektiven Plättchenfelder. Die gestörte Thrombozytopoese führt zu qualitativen Plättchendefekten mit Anisozytose, ausgeprägter Mikrozytose und zur Ausbildung atypischer Granula. Das atypische Granulomer macht 18,6% des gesamten Granulomers aus. Davon finden sich 4,6% Stäbchengranula, 5,2% Trommelschlegelgranula, 6% Ochsenaugengranula und 2,8% Riesengranula mit einem Durchmesser von 0,3–0,5μ. Die Vermehrung des Granulomer-γ und der Nachweis von zahlreichen glykogenhaltigen Plättchen weist auf eine Zunahme in der Zahl der jugendlichen Plättchen hin. Die klinisch geäußerte Vermutung, daß zu den Symptomen einer primär hämorrhagischen Thrombozythämie die Anzeichen einer Polyzythämie hinzugekommen seien, kann durch die elektronenmikroskopischen Befunde an den Megakaryozyten bestätigt werden.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0495
    Keywords: Pore water ; Seasonal changes ; Intertidal sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract In order to determine time-dependent changes in estuarine pore-water chemistry and flux variations across the sediment-water interface, sediment cores of an intertidal mud flat in the Weser Estuary were taken monthly over a one-year period. Sediment temperature, pH, Eh, Cl−, O2, NO 3 − , and SO 4 2− pore-water concentrations were measured and showed variations that relate to the changes of surface temperature and estuarine water composition. Fick's first law was applied to quantify diffusive fluxes from concentration gradients in the diffusive boundary layer and in the pore water. Total nitrate fluxes were calculated from flux chamber experiments. Diffusive oxygen fluxes increased from 5 mmol m−2 d−1 in winter to 18 mmol m−2 d−1 in early summer, while nitrate fluxes into the sediment increased from 3 mmol m−2 d−1 in winter to 60 mmol m−2 d−1 in early summer. Oxygen and nitrate fluxes into the sediment correlated linearly to sediment temperature. Sulfate fluxes increased from 0.5 mmol m−2 d−1 in winter to 10 mmol m−2 d−1 in August and September. Converted into carbon fluxes, the sum of these oxidants ranged from 10 mmol m−2 d−1 in winter to 80 mmol m−2 d−1 in summer. An estimation of the upper limit of the annual nitrate flux into the sediment showed that about 10% of the 250,000 t of nitrate discharged annually by the river may be decomposed within the inner Weser Estuary.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 24 (1994), S. 223-232 
    ISSN: 1432-0495
    Keywords: Sediments ; Heavy metals ; Estuary ; River Weser
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Studies of heavy metal concentrations in porewaters and in sediments from the Weser Estuary, Germany, indicate that the depth distribution of Mn, Cd, and Cu in the solid phase is predominantly influenced by the subsurface redox regime, while Ni shows only moderate alteration. Based on solid-phase heavy metal data from eight locations in the study area, linear regressions of Fe, Mn, Cu, Ni, and Cd on Al allowed differences between the initial metal concentration and the concentration preserved in the sediments to be predicted. We calculate that, due to early diagenetic processes, Mn is enriched to 145 percent, while Cu and Cd are depleted to 71 percent and 46 percent, respectively, of the initial metal concentration in the near-surface sediment. Maximum depletion of Cd (84 percent), Cu (68 percent), Mn (54 percent), and Ni (24 percent) concentrations in the sediment, observed at a restricted area downcore, indicate the importance of post-depositional processes to metal preservation in the sediment. Without knowledge of the quantitative effects of diagenetic reactions on the preservation of metal concentrations in sediments, the depth distribution of metals in sediment cores may be misinterpreted as the effect of human activities.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0495
    Keywords: Key words Pyrite oxidation ; Acid mine drainage ; Tailings ; landfill ; Sealing ; Modelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Annually, an amount of approximately 13 million cubic meters of hard-coal tailings must be disposed of in the German Ruhr Valley. Besides the waste of land in a densily populated region, the disposal of the pyrite-bearing material under atmospheric conditions may lead to the formation of acid mine drainage (AMD). Therefore, alternative disposal opportunities are of increasing importance, one of which being the use of tailings under water-saturated conditions, such as in backfilling of abandoned gravel pits or in the construction of waterways. In this case, the oxidation of pyrite, and hence the formation of AMD, is controlled by the amount of oxygen dissolved in the pore water of tailings deposited under water. In case the advective percolation of water is suppressed by sufficient compaction of the tailings, oxygen transport can be reduced to diffusive processes, which are limited by the diffusive flux of dissolved oxygen in equilibrium with the atmospheric pO2. Calculations of the duration of pyrite oxidation based on laboratory experiments have shown that the reduction of oxygen is mainly controlled by the content of organic substance rather than the pyrite content, a fact that is supported by results from oxidation experiments with nitrate. A "worst case" study has lead to the result that the complete oxidation of a 1.5-m layer of hard-coal tailings deposited under water-saturated conditions would take as much as several hundred thousand years.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 39 (2000), S. 839-848 
    ISSN: 1432-0495
    Keywords: Key words Baltic Sea ; Arkona Basin ; Hydrocarbons ; Transport ; Hydrocarbon sources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Surface sediments, suspended particulate matter and fluffy-layer material, collected in the Arkona Basin and the Pomeranian Bay during 1995–1997, as well as air particulate matter, collected on the island of Rügen during August 1995, were analysed for total organic carbon content, saturated and polycyclic aromatic hydrocarbons (PAH). The resulting concentrations and distributions of these compounds and molecular PAH ratios are discussed in terms of matrix, origin of the organic matter and seasonal variations. The data show that the Oder river can be identified as a major source for PAH transported into the southern part of the Arkona Basin. A strong atmospheric input of PAH is noted for the central and northern part of the basin. In general, anthropogenic and bacterially degraded hydrocarbons bound to organic carbon-rich and small particles are mainly deposited in the basin center, whereas their natural counterparts accumulate mainly on the basin flanks covered by coarser grained sediments.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 26 (1970), S. 655-656 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vasopressin and oxytocin are antagonistically effective substances with inverse dependence on concentration in the nervous system of insects. These results emphasize the central importance of neurohormonal control of general response in the nervous system.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Environmental geology 30 (1997), S. 72-80 
    ISSN: 1432-0495
    Keywords: Key words Coal mine workers' pneumoconiosis ; Coalification ; Macerals ; Organic compounds ; Phenols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The fibrogenic and cytotoxic potential of coal mine dust is independent of the amount of quartz and other inorganic parameters. Results of coal petrographical and organic geochemical investigations of coals and coal mine dust from the Ruhr and Ibbenbüren Region of Germany demonstrate variations of organic dust amount possibly influencing these noxious properties. Coal mine dust of high rank coals is characterized by a pronounced fibrogenic risk. This risk, independent of the quantity of quartz, is probably based on shape variations of different coal macerals. With increasing coalification of the corresponding seam, the vitrinite is enriched in its dust; however, lower concentrations have been determined for inertinite. Vitrinite shows constant shapes and sizes independent of the rank of coal. Inertinite particles with elongated to fibrous shapes tend to larger sizes with increasing coalification. Strikingly, coal mine dust from miners' lungs with high degrees of coal mine workers' pneumoconiosis (CWP) is enriched in inertinite. In contrast, high cytotoxicities in cell tests are known for coal mine dust from low coalified coals. High concentrations of phenolic compounds can be extracted by dichloromethane from low coalified coal mine dust. These compounds, which are characterized by a high water solubility and therefore high bioavailability, explain the high cytotoxicities of coal mine dust. Contamination of dust by diesel emissions in the coal mine can act as additionally supporting parameters for extended cytotoxicities.
    Type of Medium: Electronic Resource
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