ISSN:0021-1915    

DOI:10.1080/00211919308046698

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A review is being presented of the latest results in the use of nitrogen-15 in the soil-plant system. The literature covers the period from 1991 to early April 1993. The increase in environmentally related experiments shows that the stable nitrogen isotope technique, applied either as tracer or as the natural isotope tracing approach, is well suited particularly to ecosystem studies. This trend is supported by convenient analytical systems. An important challenge to scientists in the field of environmental research is to contrive ways and means of permitting the plants to utilize the available nitrogen in the soil more efficiently. Examples of research areas needing more attention are pointed out.

ISSN:0021-1915    

DOI:10.1080/00211919308046699

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

When tracing the fluxes of N compounds (especially N oxides) and carbon dioxide in the system soil-atmosphere and applying15N and13C, it is necessary to simultaneously determine both the concentration of the substances and their isotopic composition. GC separation (packed column) was coupled to a mass spectrometer by a special interface. Variable sample volumes can be delivered by changing the split by means of the interface in front of the MS. Thus, both the concentration of a gaseous compound and its15N content can be measured. Supplying sample volumes in a range between 5 μl and 5 ml, it is possible to measure both components of high content (e.g., nitrogen) and at the lower ppm(v)-content (e.g., dinitrogen oxide) in the air. Measurements of N2, N2O, NO and CO2are demonstrated, too.

ISSN:0021-1915    

DOI:10.1080/00211919308046700

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Hepatic detoxification capacities of three groups of infants aged about two were estimated using the [15N]methacetin elimination test, as well as standard serum parameters:1.Formerly hypotrophically born infants still too small for their age (n = 23)2.Patients suffering from severe liver diseases (n = 15)3.Patients without liver diseases (n = 14).17 of the infants of group 1 showed15N elimination rates as low as the rates of the liver-diseased patients of group 2. Compared to the infants of group 3, who had normal values, the findings reflect diminished hepatic monooxygenases activities in groups 1 and 2. On the other hand, the serum parameters of the infants of group 1 did not deviate from normal values estimated in group 3. Here only group 2 showed pathological values.Consequently, the [15N]methacetin test seems to be more sensitive in controlling hepatic parameters of growth retardations than the usual serum parameters used here. Further investigations have to answer the question to which proportion intrauterine malnutrition and postnatal effects, such as environmental living conditions, contribute to the retardation of liver function development in combination with growth retardation.

ISSN:0021-1915    

DOI:10.1080/00211919308046701

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Model coalification experiments have been carried out using organic matter in sediments from the Hils syncline. In the experiments we wanted to elucidate, to what extent different facies situations can be observed in the investigated region and which conclusions can be drawn regarding the type of originating substances for hydrocarbons adsorbed in drilling cores. As a result of chemical and isotope analyses the organic substances should be characterized not only as pure sapropelites but show in different degree the participation of humic organic matter.

ISSN:0021-1915    

DOI:10.1080/00211919308046702

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The phosphonitrilic hexamides (PNH) [15N6] hexamino-phosphatriazine and hexaminophospha-[15N3] triazine were synthesized. Vegetation experiments showed that PNH has a favourable effect on the maize growth. Also the results demonstrated that the major part of PNH is mineralized during the following days. This process diminishes after 60 days. The total N-fertilizer uptake is about 46%, 29% of which came from amino-N and 17% from cyclic N, respectively. PNH behaved as a slow releasing N-fertilizer.

ISSN:0021-1915    

DOI:10.1080/00211919308046703

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:0021-1915    

DOI:10.1080/00211919308046704

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

K. Kleinknecht:Detektoren für Teilchenstrahlung(Detectors for Particle Radiation). 3. durchgesehene und erweiterte Auflage: B. G. Teubner, Stuttgart, 1992, pp. 296; (Teubner Studienbücher - Physik), ISBN 3-519-23058-5

ISSN:0021-1915    

DOI:10.1080/00211919308046705

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0021-1915    

DOI:10.1080/00211919308046697

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor