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  • 1
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    Wageningen University
    In:  Conference on Integrated Assessment of Agriculture and Sustainable Development: Setting the Agenda for Science and Policy, (Egmond aan Zee, Netherlands, March 2009)
    Publication Date: 2010-04-12
    Type: confpaper
    Format: application/pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 154 (1984), S. 275-280 
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Green sea turtles (Chelonia mydas) are well known as endurance swimmers and divers. Physiological correlates of these traits were studied in 9 adult sea turtles (mean body mass=87 kg) at a body temperature of 25°C. The respiratory properties of the blood were similar to those of other turtles except for a higher oxygen affinity (P 50=18.2 Torr, pH 7.6), which may be an allometric function. Resting, systemic blood flow, calculated from the Fick principle was 21.5 ml·kg−1. min−1, similar to values reported for other turtles. Pulmonary blood flow, measured by mass spectrometry of acetylene uptake in the lungs was 24.0 ml·kg−1·min−1, not significantly different from the calculated systemic flow. Other evidence of a small (net) intracardiac shunt is the high arterial saturation (ca. 90%) of arterial blood. This distinctive feature of O2 transport inC. mydas provides an $$[Ca_{O_2 } - C\bar \upsilon _{O_2 } ]$$ content difference of 4.1 ml· dl−1. This results in a relatively low blood convection requirement at rest $$\dot Q_t /\dot V_{O_2 }$$ =24.4 mlbtps·mlstpd −1), similar to that for many mammals. This would favor a high maximum O2 uptake, as measured by others in this species. The relatively high O2 affinity of blood in this species could be adaptive to “loading” O2 during intermittent breathing while swimming and to utilizing the lung O2 store during the progressive hypoxia of diving.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Empirical economics 10 (1985), S. 1-11 
    ISSN: 1435-8921
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Conclusion This paper has suggested a method for determining the equivalence of multiple time series when the series are not necessarily independent. By borrowing on the seemingly-unrelated time series structure and employing separate induced tests the researcher is presented with a technique for inferring equivalence between series, and in its absence identifying the structural elements causing non-equivalence. The proposed approach is thought to be simpler to apply than previous methods, less demanding of computational resources and overcomes at least two major difficulties (the assumption of independence and the problem of extending the results to more than two series, inherent in earlier time series equivalence determination strategies.
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  • 4
    ISSN: 1573-4919
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The relevance of the crystal structure of the polypeptide hormones, insulin, glucagon and human placental lactogen to conformation and flexibility in solution and to receptor binding is considered. X-ray studies for crystal forms of glucagon, human placental lactogen and three insulin derivatives (A1 acetyl insulin, A1-t-butoxy carbonyl insulin and A1 2,2-dimethyl-3-formyl-L-thiazolidine-4-carbonyl insulin) are reported. Neither glucagon nor human placental lactogen are as ordered as insulin in the crystal form. Glucagon crystals undergo distinct transformations on changing the pH of the mother liquor from pH 9.5 to pH 6, indicating that the glucagon molecule is flexible in the crystal, as it is in solution. On the other hand all insulin analogues have a similar three dimensional structure to that of native insulin. Three dimensional difference Fourier studies of two insulin derivatives at 3 Å resolution indicate the position of the modifying groups and define the small conformational changes which have occurred. Thein vitro biological activity and receptor binding decrease with the increasing size of the group added to A1. The correlation of the structure analysis with the biological data strongly implicate a region close to A1 in receptor binding. Insulin appears to bind to the receptor in a specific conformation similar to that observed in the crystal structure and in solution; amino acid residues which are separated in the primary structure but brought into close juxtaposition in the tertiary structure are important for full potency.
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  • 5
    ISSN: 1438-1168
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Description / Table of Contents: Zusammenfassung ¶Experimentelle Bestimmung der hydrothermalen Löslichkeit von Platingruppen-Elementen unter besonderer Berücksichtigung von Porphyry Copper-Systemen Wir haben eine Reihe von Experimenten zur Löslichkeit von metallischem Osmium und Palladium in überkritischen wässrigen KCl Fluiden durchgeführt. Dabei war pH durch die Assoziation K-Feldspat-Quarz-Muskovit gepuffert, die Sauerstoff-Fugazität wurde durch verschiedene Sauerstoffpuffer bei 400 und 500°C kontrolliert. Ein wichtiges Ziel dieser sorgfältig eingegrenzten Experimente war es, die derzeit bestehenden theoretischen Modelle zur PGE-Löslichkeit zu testen. Unsere experimentellen Ergebnisse zeigen, dass die Konzentration von Osmium in einer 1,0 m KCl-Lösung mit Ni-NiO (NNO) Puffer bei 500°C ungefähr 3 ppb (≈ 1,9 × 10−8 mol/kg H2O) beträgt, wogegen die Konzentration von Osmium in einer 1,5 m KCl-Lösung, auch durch NNO bei 500°C gepuffert, bei ≈ 130 ppb (≈ 6,5 × 10−7 mol/kg H2O) liegt. Dass der pH in beiden Experimenten fast identisch ist, weist darauf hin, dass Osmium in der Lösung als Chloridkomplex vorliegt. Die Konzentration von Osmium in einer 1,5 m KCl-Lösung, aber mit einem Puffer mit höherer Sauerstoff-Fugazität (Re-ReO2) (RRO) gepuffert, ist ungefähr um eine Größenordnung höher (≈ 1705 ppb; ≈ 1 × 10−5 mol/kg H2O). Die Palladium-Konzentration in einer 0,1 m KCl-Lösung, die durch RRO bei 500°C gepuffert wird, und in einer 0,1 m KCl-Lösung, die bei 400°C durch MnO-Mn3O4 gepuffert wird, sind 40 ppb (≈ 3,8 × 10−7 mol/kg H2O) und ungefähr 15 ppb (1,4 × 10−7 mol/kg H2O). Unsere experimentellen Ergebnisse zur Löslichkeit von Palladium-Metall zeigen, zusammen mit Geländebeobachtungen, dass die theoretischen Berechnungen von Sassani und Shock (1990, 1998) die Löslichkeit von Palladium unter superkritischen Bedingungen um viele Gröβenordnungen unterschätzen. Dies lässt sich direkt auf Porphyry Copper-Systeme anwenden, weil in diesen Temperaturen, pH, Salinität und Sauerstoff-Fugazität den experimentellen Parametern weitgehend entsprechen. Die Anwendung unserer experimentellen Ergebnisse zeigt, dass ein typisches Porphyry Copper-System mindestens 40 t Palladium transportieren kann, wenn Quellen von Platingruppen-Elementen (PGE) verfügbar sind und wenn die Phase, die die Löslichkeit kontrolliert, metallisches Pd ist. In ähnlicher Weise läβt sich die Menge von Osmium, die in einem typischen Porphyry-System transportiert werden kann, mit mindestens 3 t berechnen. Porphyry-Systeme sind somit in der Lage, ausreichend PGE zu transportieren, um zumindest PGE-Lagerstätten mittlerer Gröβe zu erzeugen. Das Fehlen von bedeutendem Osmium-Mineralisation in bekannten Porphyry-Lagerstätten läβt sich entweder auf das Fehlen geeigneter Metallquellen, oder auf die Anwesenheit von Osmium in weniger löslichem Form, wie z.B. als Sulfid, zurückführen.
    Notes: Summary  We have conducted a series of experiments on the solubility of metallic osmium and palladium in supercritical aqueous KCl fluids in which pH was buffered by the assemblage K-feldspar-quartz-muscovite and oxygen fugacity was controlled by various oxygen buffers at 400° and 500°C. An important objective of these well-constrained experiments is to evaluate current theoretical models of PGE solubility. Our experimental results indicate that the concentration of Os in a 1.0 m KCl solution buffered by the Ni-NiO (NNO) assemblage at 500°C is ∼ 3 ppb (∼1.9 × 10−8 moles/kg H2O), whereas the concentration of Os in a 1.5 m KCl solution also buffered by NNO at 500°C is ∼ 130 ppb (∼ 6.5 × 10−7 moles/kg H2O). As the pH in these two experiments is nearly the same, this finding implies that Os is present in solution as a chloride complex. The concentration of Os in a 1.5 m KCl solution but buffered by a higher oxygen fugacity buffer (Re-ReO2 assemblage) (RRO) is about one order of magnitude higher (∼ 1705 ppb; ∼ 1 × 10−5 moles/kg H2O). The palladium concentrations in a 0.1 m KCl solution buffered by RRO at 500°C and in a 0.1 m KCl solution buffered by MnO-Mn3O4 at 400°C are ∼ 40 ppb (∼ 3.8 × 10−7 moles/kg H2O) and ∼ 15 ppb (1.4 × 10−7 moles/kg H2O), respectively. Our experimental results on the solubility of Pd metal in combination with field observations show that the theoretical calculations of Sassani and Shock (1990, 1998) on palladium underestimate the solubility of palladium by many orders of magnitude under supercritical conditions. Our experimental results are directly applicable to porphyry copper systems because in such systems temperature, pH, salinity and oxygen fugacity are similar to the experimental parameters. Application of our experimental results indicate that a typical porphyry systems can transport at least 40 tons of Pd if sources of platinum-group elements (PGE) are available and the solubility-controlling phase is metallic Pd. Similarly, the amount of osmium that can be transported in a typical porphyry system is calculated to be at least ∼ 3 tons. Consequently, porphyry systems have the capacity to transport sufficient PGE to form at least mid-sized PGE deposits. The absence of important Os mineralization in known porphyry deposits may be due to the lack of availability of source materials, or to the presence of Os in less soluble forms, such as sulfides.
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  • 6
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
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  • 7
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
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  • 8
    Publication Date: 2019-07-17
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
    Format: application/pdf
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  • 9
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The in vitro calcifiability and molecular weight dependence of calcification of the polypentapeptide, (L · Val1-L· Pro2-Gly3-L · Val4-Gly5)n, which had been γ-irradiation cross-linked have been determined when exposed to dialyzates of normal, nonaugmented fetal bovine serum. The material was found to calcify: calcifiability was found to be highly molecular weight dependent and to be most favored when the highest molecular weight polymers (n ≈240) had been used for cross-linking. The in vivo biocompatibility, biodegradability, and calcifiability of the γ-irradiation cross-linked polypentapeptide were examined in rabbits in both soft and hard tissue sites. The material was found to be biocompatible irrespective of its physical form and to be biodegradable but with n of 200 or less it was not shown to calcify or ossify in the rabbit tibial nonunion model.
    Additional Material: 12 Ill.
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  • 10
    ISSN: 1432-1955
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Serum concentrations of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were studied in mice infected with eitherSchistosoma japonicum orS. mansoni cercariae. Sera from uninfected mice were negative for both antigens. CAA was detectable in theS. japonicum-infected mice as early as at 2 weeks post-infection (p.i.), and levels were higher in these animals than in theS. mansoni-infected group during the full study period. At the moment of perfusion, 10 weeks p.i., a median of 9 and 29 worms, respectively, were recovered from theS. japonicum-andS. mansoni-infected mice, and the median CAA levels were 326 and 27 ng/ml, respectively. In contrast, CCA levels were much lower in theS. japonicum-infected group (27 ng/ml) as compared with theS. mansoni-infected mice (282 ng/ml). These results suggest an important difference betweenS. japonicum andS. mansoni infections in CAA and CCA production and/or clearance and indicate a significant role for CAA in the diagnosis of human schistosomiasis japonicum.
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