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71.
A case of aortic atresia with insufficiency of mitral valve diagnosed prenatally at 33 weeks of gestation is presented. An accurate diagnosis of this fetal cardiovascular malformation was possible by application of Doppler colour flow mapping, which demonstrated (a) the absence of forward flow in the hypoplastic ascending aorta, (b) reverse flow of blood from the ductus arteriosus into the severely hypoplastic ascending aorta in the late systole, (c) pansystolic mitral valve regurgitation, and (d) absent flow across the foramen ovale as a result of premature closure of the foramen ovale.  相似文献   
72.
This report of an international conference about the problems around lakeshores, their evaluation and the possibilities to improve the situation for lake shores, continues the series ‘Lake shores, a forgotten ecotone’ as article 4. Five main topics were discussed: (1) applied ecology of lakeshores, (2) human impact, (3) ecological assessment, (4) protection and restoration, (5) sustainable development and use of lake shores.  相似文献   
73.
Nematodentest     
For the assessment of contaminated and remediated soils and substrates, and the estimation of chronic toxicity of soil contaminations, an ecotoxicological test was developed using the terrestrial nematodePanagrellus redivivus. The population dynamics expressed by the reproduction factor (VF) allows an estimation of soil quality within seven days. Due to the rapid generation time ofPanagrellus (< 5 d), the short test duration is considered to be sufficient. The suitability of this test duration is considered to be sufficient. The suitability of this test was evaluated by investigating soils which had been contaminated using applications of specific pollutants (lindane and PCB 52).  相似文献   
74.
The concentrations of Ag, Al, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, Sr, Ti, V and Zn were determined by AES/ICP inMolinia caerulea andEriophorum vaginatum grown in the Leegmoor, which is in reinstatement. In the soil substrate analytical detection limits were obtained for Ag, Co, Li, Mo and Rb and additionally for Al, Be, Cd, Cr, La, Li, Ni, Pb, Ti and V in plants. Compared with mineral soils, the concentration of elements in peat is low. The elements K and P were enriched byMolinia caerulea andEriophorum vaginatum, and in addition Mn and Zn byEriophorum vaginatum. Altogether the ability of accumulation essential elements seem to be more efficient byEriophorum vaginatumthan byMolinia caerulea, which can be an ecophysiological advantage on peats, whereMolinia caerulea is normally not distributed.  相似文献   
75.
Diphenylarsenic chloride (CLARK I) and diphenylarsenic cyanide (CLARK II) react quickly and quantitatively with dimercaptanes at room temperature to yield diphenylarsine thiolthioether. The thiolthioethers could be identified using mass spectrometry. This reaction can be used for the gas-chromatographic detection of diphenylarsenic compounds.  相似文献   
76.
[1-(13)C]-labelled phenanthrene was incubated in a closed bioreactor to study the flux and biotransformation of polycyclic aromatic hydrocarbon (PAH) in contaminated soils on a bulk and molecular level. The degradation of extractable phenanthrene was observed by GC-MS measurements and the mineralisation was monitored by (13)CO(2) production. The transformation of the (13)C-label into non-extractable soil-bound residues was determined by carbon isotopic measurements. With these data we were able to calculate a carbon budget of the (13)C-label. Moreover, the chemical structure of non-extractable bound residues was characterised by applying selective chemical degradation reactions to cleave xenobiotic subunits from the macromolecular organic soil matrix. The obtained low molecular weight products yielded (13)C-labelled compounds which were identified using IRM (isotope ratio monitoring)-GC-MS and structurally characterised with GC-MS. Most of the (13)C-labelled products obtained by chemical degradation of non-extractable bound residues are well-known metabolites of phenanthrene. Thus, metabolites of [1-(13)C]phenanthrene formed during biodegradation appear to be reactive components which are subsequently involved in the bound residue formation. Hydrolysable amino acids of the soil residues were significantly labelled with (13)C as confirmed by IRM-GC-MS measurements. Therefore, phenanthrene-derived carbon was transformed by anabolic microbial processes into typical biologically derived compounds. These substances are likely to be incorporated into humic-like material after cell death.  相似文献   
77.
78.
Zusammenfassung  Da es in einer Industriegesellschaft unm?glich ist, die Belastungen von ?kosystemen auf ein Ma? zu reduzieren, das jegliche Sch?digung ausschlie?t, besteht die Notwendigkeit der Bewertung. Eine der zur Verfügung stehenden Bewertungstechniken ist der ?konomische Ansatz. In der Artikelserie wird dieser Ansatz am Beispiel des Bodens vorgestellt. Im vorliegenden dritten Teil wird die Berücksichtigung des Faktors Zeit durch die sogenannte Diskontierung erl?utert. Auf den ersten Blick führt die Diskontierung dazu, da? Sch?den durch Umweltbelastungen, die m?glicherweise erst von zukünftigen Generationen getragen werden müssen, für die gegenw?rtige Generation (die diese Sch?den verursacht) in ihrer Bedeutung reduziert werden. Vor diesem Hintergrund werden verschiedene Begründungen für die Diskontierung diskutiert und es wird gezeigt, warum die Diskontierung auch bei einer intergenerativen Abw?gung von Kosten und Nutzen unverzichtbar ist. Die Pr?ambel zu diesem Beitrag ist ver?ffentlicht in UWSF 2/99, S. 119, 1999.  相似文献   
79.
Zusammenfassung  Phenylarsindichlorid (PFIFFIKUS) reagiert bei Raumtemperatur in einer Gleichgewichtsreaktion schnell mit Alkoholen unter Bildung von Phenylarsinbisether und Phenylarsinchloridether. Die Reaktionen verlaufen nicht quantitativ. Die Derivate wurden massenspektrometrisch identifiziert.   相似文献   
80.
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