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  • 2005-2009  (1)
  • 1975-1979  (2)
  • 1970-1974  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Long-term response of a shallow, moderately flushed lake to reduced external phosphorus and nitrogen loading (2005)
    Oxford, UK : Blackwell Science Ltd
    Freshwater biology 50 (2005), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: 1. The responses of nutrient concentrations, plankton, macrophytes and macrozoobenthos to a reduction in external nutrient loading and to contemporary climatic change were studied in the shallow, moderately flushed Lake Müggelsee (Berlin, Germany). Weekly to biweekly data from 1979 to 2003 were compared with less frequently collected historical data.2. A reduction of more than 50% in both total phosphorus (TP) and total nitrogen (TN) loading from the hypertrophic (1979–90) to the eutrophic period (1997–2003) was followed by an immediate decline in TN concentrations in the lake. TP concentrations only declined during winter and spring. During summer, phosphorus (P) release from the sediments was favoured by a drastic reduction in nitrate import. Therefore, Müggelsee acted as a net P source for 6 years after the external load reduction despite a mean water retention time of only 0.1–0.16 years.3. Because of the likely limitation by P in spring and nitrogen (N) in summer, phytoplankton biovolume declined immediately after nutrient loading was reduced. The formerly dominant cyanobacteria (Oscillatoriales) Limnothrix redekei and Planktothrix agardhii disappeared, but the mean biovolume of the N2-fixing species Aphanizomenon flos-aquae remained constant.4. The abundance of Daphnia spp. in summer decreased by half, while that of cyclopoid copepod species increased. Abundances of benthic macroinvertebrates (mainly chironomids) decreased by about 80%. A resource control of both phytoplankton and zooplankton is indicated by significant positive correlations between nutrient concentrations and phytoplankton biovolume and between phytoplankton and zooplankton biomass.5. Water transparency in spring increased after nutrient reduction and resulted in re-colonisation of the lake by Potamogeton pectinatus. However, this process was severely hampered by periphyton shading and grazing by waterfowl and fish.6. Water temperatures in Müggelsee have increased in winter, early spring and summer since 1979. The earlier development of the phytoplankton spring bloom was associated with shorter periods with ice cover, while direct temperature effects were responsible for the earlier development of the daphnid maximum in spring.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.2005.01430.x
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Die dringliche Pankreatektomie bei der akuten Pankreatitis (1971)
    Springer
    Langenbeck's archives of surgery 328 (1971), S. 314-327 
    Details
    ISSN: 1435-2451
    Keywords: Pancreatitis ; Surgery ; Acute Pancreatitis ; Pancreatectomy ; Acute Pancreatitis-Complications
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Das Studium von 17 Fällen, bei denen eine Frühpankreatektomie durchgeführt wurde, bestimmt wie folgt unser therapeutisches Verhalten: Bei der akuten postoperativen Pankreatitis sind wir angesichts des schwerwiegenden Krankheitsverlaufes überzeugt von der Notwendigkeit einer frühzeitig durchzuführenden ausgedehnten Pankreatektomie. Bei der akuten primären Pankreatitis sind wir etwas zurückhaltender, da selbst bei offener Bauchhöhle das Schicksal gewisser Pankreaspartien nicht mit Sicherheit vorhergesagt werden kann. Dennoch bestimmen unsere im Vergleich mit den Literaturangaben günstigen persönlichen Erfahrungen mit der Pankreatektomie unser aktives chirurgisches Vorgehen bei der akuten nekrotisierenden hämorrhagischen Pankreatitis.
    Notes: Summary The study of 17 cases of acute pancreatitis, in whom early total or subtotal pancreatic resection were performed, has led to the following therapeutic principles: the serious nature of acute post-operative pancreatitis has convinced us of the necessity for early intervention and as extensive a resection as possible; 5 out of 6 patients were cured in this way. In case of acute primary pancreatitis we are more conservative since even at laparotomy it is difficult to foresee the fate of all parts of the pancreas. Nevertheless our relatively favorable results led us to intervene surgically if the signs and symptoms of pancreatitis do not show any improvement after 8 to 12 h. If acute, diffuse pancreatitis affects the whole organ subtotal pancreatectomy is performed. If the head of the pancreas is affected we confine ourselves to the removal of necroses. Duodenopancreatectomy does not seem justified in the acute phase; only 1 out of 3 patients survived this procedure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01237507
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Experimentelle Untersuchung des statistischen Größeneinflusses im Dauerschwingversuch an ungekerbten Stahlproben (1975)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 6 (1975), S. 52-54 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Experimental Investigation of the Statistical Size-Effect in Fatigue Tests with Unnotched Specimens.In constant-load-fatigue-tests with unnotched specimens of different lengths, the statistical effect of specimen's size in probability of lifetime to fracture was determined.
    Notes: Im einstufigen Dauerschwingversuch an ungekerbten Proben mit unterschiedlichen Meßlängen konnte der statistische Einfluß der Probengröße auf deren Bruchwahrscheinlichkeit experimentell nachgewiesen werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19750060204
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Experimentelle und klinische Untersuchungen zur Pathophysiologie der Nierenarterienstenose * (1976)
    Springer
    Langenbeck's archives of surgery 340 (1976), S. 147-158 
    Details
    ISSN: 1435-2451
    Keywords: Renal artery stenosis - Fluid mechanics ; pathophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung In der vorliegenden experimentellen und klinischen Untersuchung wird die Auswirkung der Nierenarterienstenose auf die poststenotische Durchblutung der Niere dargestellt und beurteilt. Es wird gezeigt, daß der Anteil des Durchblutungswiderstandes einer mittelgradig stenosierten Niere am Gesamtwiderstand gering ist. Die periphere durch die Stenose induzierte Widerstandserhöhung ist das wesentliche Merkmal in der Pathophysiologie der Nierenarterienstenose und der hierdurch bedingten Druckerhöhung. Sie tritt zunächst auf der stenosierten, dann auch auf der nichtstenosierten Seite auf und kann durch den Renin-Angiotensin-Mechanismus erklärt werden. Die Nierendurchblutung kann durch Beseitigung der experimentellen Nierenarterienstenose normalisiert werden. Analog ist die Nierendurchblutungsminderung durch Beseitigung der Stenose im Anfangsstadium der klinischen Nierenarterienstenose zu beheben. Der induzierte arterielle Hochdruck geht zurück. Da der Widerstand im Initialstadium wesentlich. auf die erkrankte Niere beschränkt ist, kann der Gesamtwiderstand für beide Nieren nur gering erhöht sein. Bei höherem Widerstand beider Nieren ist eine Gefäßveränderung im peripheren Gefäßabschnitt gegeben. Eine Beseitigung der Stenose kann nicht mehr zur Reduktion des arteriellen Hochdrucks führen. Dies läßt sich anhand der Daten unseres Krankengutes nachweisen. Die kritische Grenze für die Indikation zum operativen Vorgehen scheint vorzuliegen, wenn der Globalwiderstand für beide Nieren einen Wert von 0,25 mm Hg/ml min−1 überschritten hat.
    Notes: Summary The effect of renal artery stenosis on the poststenotic hemodynamics is demonstrated and evaluated in the presented experimental and clinical investigation. It is shown that the resistance of a medium sized stenosis is small compared to the total renal resistance. The peripheral resistance which is induced by the stenosis is the essential characteristic in the pathophysiology of the renal artery stenosis and the resulting hypertension. The increasing pressure can be measured primarily in the stenosed artery and later also in the not stenosed side and is seen as an effect of the renin-angiotensin-mechanism. The renal artery flow returns to normal after removal of the experimental stenosis. Likewise the reduction in renal artery flow is normalized by resection of the stenosis in the initial phase of the clinical renal artery stenosis. The induced hypertension is reversed to normal. Since the resistance in the initial phase is essentially limited to the stenosed side the global renal resistance is only little increased. Increased total renal resistance is due to morphological changes in the peripheral vessels. The removal of the stenosis will not be followed by a decrease in blood-pressure. This is to be seen in the data of our clinical cases. The critical limit for an effective operation followed by a decrease in artery pressure is to be seen in a total renal resistance of over 0.25 mm Hg/ml min−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254852
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    Paper (German National Licenses)
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