ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Analytical Chemistry and Spectroscopy  (1)
  • Nitrogen mineralization  (1)
  • Organic Chemistry  (1)
  • 2005-2009
  • 1985-1989  (2)
  • 1970-1974  (1)
Collection
Publisher
Years
Year
  • 1
    ISSN: 1432-0789
    Keywords: Decomposition ; Mesh bag ; Nitrogen mineralization ; 15N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In two field experiments, plant materials labelled with 15N were buried separately within mesh bags in soil, which was subsequently sown with barley. In the first experiment, different parts of white clover (Trifolium repens), red clover (T. pratense), subterranean clover (T. subterraneum), field bean (Vicia faba), and timothy (Phleum pratense) were used, and in the second, parts of subterranean clover of different maturity. The plant materials were analysed for their initial concentrations of total N, 15N, C, ethanol-soluble compounds, starch, hemicellulose, cellulose, lignin, and ash. After the barley had been harvested, the bags were collected and analysed for their total N and 15N. In the first experiment the release of N was highest from white clover stems + petioles (86%) and lowest from field bean roots (20%). In stepwise regression analysis, the release of N was explained best by the initial concentrations of lignin, cellulose, hemicellulose, and N (listed according to decreasing partial correlations). Although the C/N ratio of the plant materials varied widely (11–46), statistically the release of N was not significantly correlated with this variable. The results of the second experiment using subterranean clover of different maturity confirmed those of the first experiment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 10 (1987), S. 548-552 
    ISSN: 0935-6304
    Keywords: Glass capillary gas chromatography ; Immobilization ; OV-240-OH cyanopropylpolysiloxane ; Isomer specificity ; Polychlorinated dibenzo-p-dioxins ; Polychlorinated dibenzofurans ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Glass capillaries were leached, dehydrated, persilylated with 1, 3-bis (3-cyanopropyl) tetramethyldisiloxane, and coated with OV-240-OH. After crosslinking and binding the phase to the glass surface the columns showed high separation efficiency, high temperature stability, and inertness comparable to persilylated apolar columns. Column performance is shown to be superior to liquid phase cyanopropyl columns such as SP 2330. The excellent separation capabilities together with the selectivity of the phase makes OV-240-OH coated columns a valuable tool for the determination of toxic isomers in complex mixtures of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). The order of elution of individual TCDD isomers was found to be similar to that described for SP 2330 or Silar 10c. The detection of PCDDs and PCDFs in a fly ash extract further illustrates the utility of OV-240-OH coated columns. The high temperature limit of these columns opens the way for the analysis of high boiling compounds such as mixed brominated/chlorinated dibenzo-p-dioxins and dibenzofurans.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 53 (1970), S. 964-973 
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In a search for a new and efficient synthesis of the compound 7, the cyclization of 5 (obtained by a Michael-reaction from 3 and 4) was studied. Treatment of 5 with strong acid furnished the known dienedione 8. Mild acidic conditions gave the bridged alcohol 9 and other, unidentified products, rather than the desired enone 6. Under basic conditions, 5 did not cyclize to 6, but underwent retro-Michael reaction. Attempts were then made to convert the dienedione 8 to the 14α-enone 19. However, both catalytic hydrogenation and lithium-ammonia reduction of 8 yielded mainly 14β-products. In some hydrogenation experiments, isomerization of the dienedione 8 to the phenols 13 (major) and 14 (minor) occurred. The stereochemistry of the new isomeric des-A-androst-9-en-5, 17-diones (16, 17 and 20) was determined by chemical and spectroscopic methods.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...