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  • 1
    Electronic Resource
    Electronic Resource
    Investigation of the kinetic mechanism for the ion-assisted etching of GaAs in Cl2 using a modulated ion beam (1985)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 58 (1985), S. 4670-4678 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: There is increasing technological interest in using Cl2 and Cl-containing compounds in the dry plasma etching of III–V semiconductors. This paper presents a study of the ion-assisted etching of GaAs by Cl2 using a modulated ion beam technique to gain insight into the kinetic mechanism of this process. The etching rate increases with increasing ion energy (0.3–3 kV) and depends linearly on ion flux (1.0–10.0×1014 ions cm2 s). The etching rate increases with increasing Cl2 pressure up to a saturation limit near 2×10−6 Torr. This saturation limit is independent of the ion flux coincident on the surface within the range studied. The ion-enhanced etching rate decreases with increasing sample temperature over the range 300–500 K. Major etch products are AsCl3 and GaCl2 (and possibly GaCl), and the time dependence of the increase in these mass spectrometer signals following the initiation of the ion pulse is consistent with all of the products having a most probable translational energy of ∼0.14 eV. There is an additional delay in the appearance of the AsCl3 signal which roughly corresponds to a first order reaction with an associated time constant of 1.1 ms. One possible kinetic mechanism for the ion-enhanced etching is proposed which involves the surface reactions of Ga and AsCl with adsorbed chlorine. In this model, the ∼1 ms delay in the appearance of the AsCl3 is attributed to the lifetime of potential energy excitation caused by the ion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.336241
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  • 2
    Electronic Resource
    Electronic Resource
    An intense cold core eddy in the North-East Atlantic (1986)
    [s.l.] : Nature Publishing Group
    Nature 319 (1986), S. 474-477 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Western basin cold core eddies are spawned from Gulf Stream meanders that intensify, grow into loops, and pinch off from the main stream to form rings of current that wander independently in the waters to the south and south-east of the Gulf Stream3. They are readily distinguishable from other ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/319474a0
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  • 3
    Electronic Resource
    Electronic Resource
    Omega-oxidized leukotriene B4 detected in the broncho-alveolar lavage fluid of patients with non-cardiogenic pulmonary edema, but not in those with cardiogenic edema (1991)
    Springer
    Intensive care medicine 17 (1991), S. 1-6 
    Details
    ISSN: 1432-1238
    Keywords: Lung edema ; Acute respiratory distress syndrome ; Leukotrienes ; LTB4 ; Omega-oxidation products of LTB4 ; Broncho-alveolar lavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Leukotriene (LT) generation has been implicated in the pathogenesis of the acure respiratory distress syndrome, ARDS. In the present study, we analysed broncho-alveolar lavage fluids of patients on mechanical ventilation because of ARDS (17 samples taken from 9 patients) or because of cardiogenic edema (8 samples taken from 6 patients) and of healthy volunteers (10 samples from different donors). LTs were separated as methylated and non-methylated compounds using different HPLC procedures, and were identified by chromatographic mobility, on-line UV-spectrum analysis and post HPLC immunoreactivity. In the lavage samples of the healthy volunteers and the patients with cardiogenic edema, no LTs were detected by these technicues (detection limit≃0.1–0.2 ng/ml lavage fluid). By contrast, in 15 out of 17 samples from patients with ARDS LTB4 or its metabolites 20-OH-LTB4 and 20-COOH-LTB4 were detected. The endproduct of omega-oxidation, 20-COOH-LTB4, represented the quantitatively predominant compound, detected in the range of 0.3–2.6ng/ml perfusate. We conclude that the chemotactic agent LTB4 may be involved in the amplification of inflammatory events encountered in ARDS, and that the oxidized metabolites of LTB4 are particularly suitable for monitoring lung leukotriene generation under conditions of neutrophil efflux and oxidative stress.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01708400
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  • 4
    Electronic Resource
    Electronic Resource
    Imaging of cerebral arterio-venous malformations by transcranial colour-coded real-time sonography (1990)
    Springer
    Neuroradiology 32 (1990), S. 280-288 
    Details
    ISSN: 1432-1920
    Keywords: Transcranial Doppler sonography ; Duplex scanning ; Arterio-venous malformation ; Real-time sonography ; Transcranial color-coded sonography ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Transcranial color-coded real-time sonography (TCCS) is a new diagnostic method allowing the non-invasive imaging of parenchymal and vascular structures of the adult brain through the intact skull. A description of the sonographic findings in two patients presenting with a radiologically ascertained arterio-venous malformation is provided. The AVM's can be depicted in the two-dimensional B-mode image as echodense areas interspersed with zones of lower echodensity. Their extension correlated with corresponding MRI images. The color-coded illustration of intravascular flow phenomena allowed the distinct identification of the major afferent feeding vessels, the venous drainage and of the vascular convolution of both AVM's. Information on hemodynamics, as e.g. the blood supply of the angioma by the contralateral internal carotid artery, are obtained by color-coded identification of intravascular flow direction including analysis of the Doppler frequency spectrrum. All findings obtained by TCCS complied with those established by angiography. We conclude, that TCCS is a suitable method for early diagnosis and long term follow up of cerebral AVM's.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00593046
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  • 5
    Electronic Resource
    Electronic Resource
    Reliability of transcranial colour-coded real-time sonography in assessment of brain tumours: correlation of ultrasound, computed tomography and biopsy findings (1994)
    Springer
    Neuroradiology 36 (1994), S. 585-590 
    Details
    ISSN: 1432-1920
    Keywords: Brain tumours ; Ultrasonography ; Computed tomography ; Stereotactic biopsy ; Transcranial colour-coded real time sonography ; Glloma ; Central nervous system ; Duplex sonography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Transcranial colour-coded real-time sonography (TCCS) was carried out in 25 patients with brain tumours to determine whether this noninvasive method provides additional information about the extent of solid tumour, its differentiation from oedema, and its tissue components. All 25 patients had serial computed tomography (CT)-guided stereotactic biopsies. Comparison of ultrasound, CT and histological findings revealed that the vast majority of contrast enhancing areas on CT were hyperechogenic (32/33; 97%) and contained tumour tissue (29/32; 91%). Hyperechogenic areas always represented solid tumour (23/23 patients), even when CT showed low density non-enhancing lesions. In lestons hypoechogenic on TCCS and low density on CT, histology consistently revealed necrotic tumour (7/7). Biopsies obtained from parenchyma with normal echogenicity revealed tumour in only 3 of 16 speciemens. Despite the high specificity of TCCS in the differentiation of tumour components, its sensitivity to tumour was inferior to that of CT (24/25; 96%). TCCS thus allows noninvasive preoperative identification of tumour tissue and its extent setting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00600414
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  • 6
    Electronic Resource
    Electronic Resource
    Net-building behaviour, tolerance and development of two caddisfly species from the river Rhine (Hydropsyche contubernalis and H. pellucidula) in relation to the oxygen content (1987)
    Springer
    Oecologia 73 (1987), S. 242-250 
    Details
    ISSN: 1432-1939
    Keywords: Net-building behaviour ; Development ; O2-deficiency tolerance ; Hydropsyche ; River Rhine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Tolerance, growth and development of H. contubernalis and H. pellucidula were analyzed at different O2-concentrations to determine the species specific potency amplitude in relation to O2-concentration. In addition netbouilding behaviour was compared at different O2-concentrations and current velocities. Under anaerobic conditions slightly greater tolerance was observed in H. contubernalis than in H. pellucidula. But at a higher O2-concentration H. contubernalis showed a distinctly higher O2-deficiency tolerance than H. pellucidula in relation to net-building activity, growth and development. In addition, more than 50% of H. contubernalis instars built capture nets with regular meshes at an O2-saturation of only 30% (15°C). High growth rates were also found at 50% O2-saturation and more than half the larvae developed into imagos. In addition to diminished net-spinning activity the mean growth rate started to decrease at an O2-saturation of 70% to 38% and the development into an imago was not possible in H. pellucidula. Because H. contubernalis corresponds to a regulative type, being able to maintain a high level of netbuilding activity, growth rate and development over a wide range (50% to 100% O2-saturation). On the other hand H. pellucidula corresponds to a conform type, because physiological efficiency decreases rapidly with falling O2-concentration, so that development into an imago is no longer possible below 85% O2-saturation. Positive correlation between net-spinning activity and tested current velocity between 10 cm/s and 25 cm/s (15°C) was found in H. pellucidula. H. contubernalis showed no change in net-building activity, over this range of current velocity. H. contubernalis can be classified as an euryoecious species with a great potency amplitude in relation to O2-concentration and current velocity. The high tolerance to O2-deficiency conditions probably allowed the early recolonization of the Mittel-and Niederrhein when a distinct O2-deficit (mean 29%, max 56%) could still be measured. H. contubernalis can be considered a bioindicator of O2-deficiency situations. Undisturbed development of H. pellucidula in this section of the river requires a further improvement in O2-content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00377514
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  • 7
    Electronic Resource
    Electronic Resource
    Osteoporoseprävention durch postmenopausale Östrogen-Gestagen-Substitution — Langzeitergebnisse und Compliance (1993)
    Springer
    Archives of gynecology and obstetrics 254 (1993), S. 296-297 
    Details
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02265998
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  • 8
    Electronic Resource
    Electronic Resource
    Wird „Phoenix 3.42“ den Erwartungen gerecht? — Erste Erfahrungen mit einem klinisch-onkologischen Datenverarbeitungsprogramm der neuen Generation (1993)
    Springer
    Archives of gynecology and obstetrics 254 (1993), S. 1145-1146 
    Details
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02266342
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  • 9
    Electronic Resource
    Electronic Resource
    A new concept for the assessment of the oxygen situation in a shelf sea area (1994)
    Springer
    Ocean dynamics 46 (1994), S. 263-275 
    Details
    ISSN: 1616-7228
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Zusammenfassung Die Sauerstoff-Bedingungen in der unteren Wasserschicht eines Schelfmeeres werden im allgemeinen durch die O2-Konzentration dicht über dem Meeresboden charakterisiert, weil diese für die Boden-Organismen besonders wichtig ist und am Boden häufig O2-Mangel herrscht. Für andere Umwelt-Aspekte muß man die gesamte Wassersäule in die Betrachtung einbeziehen. Daher wird ein neuer Sauerstoffmangel-Index vorgeschlagen. Er ist definiert durch das Sauerstoff-Defizit in der Schicht zwischen dem Meersboden und der Tiefe mit 100% O2-Sättigung. Beide Indexe ergänzen einander. Sie können angewendet werden a) zur Beurteilung der aktuellen Sauerstoff-Situation b) zur Erkennung von zeitlichen Veränderungen und Trends c) zum Vergleich der der Sauerstoff-Bedingungen in verschiedenen Gebieten. Zum Vergleich von Stationen mit unterschiedlichen Wassertiefen wird der Sauerstoffmangel-Index auf die Wassertiefe bezogen. Die Indexe werden anhand von praktischen Beispielen aus der südwestlichen Ostsee erläutert.
    Notes: Summary Usually, the oxygen conditions in the lower water layer of a shelf sea area are characterized by the oxygen concentration immediately above the bottom, because this concentration is essential for the bottom living organisms, and as there may be a high oxygen demand due to benthic respiration For other environmental aspects, however, the vertical distribution in the whole water column must be taken into account. So, a new oxygen deficiency index is proposed. It is difined by the oxygen deficit in the layer between the bottom and the depth witl: 100% oxygen saturation, Both indexes complement each other. They can be used for a) Characterizing the actual oxygen situation, b) recongnizing temporal changes and trends, c) comparing the oxygen conditions in different areas. For comparison of stations with different depths, the oxygen dificiency index is related to (=divided by) the water depth. Some examples are given for temporal variations and trends and for spatial differences of the oxygen situation in the south-western Baltic Sea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02226954
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  • 10
    Electronic Resource
    Electronic Resource
    Über die analytische Bestimmung der Vitamine A, B1, B2 und C (1939)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 117 (1939), S. 284-297 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01470729
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