Imaging of humic substance macromolecular structures in water and soils

Science

Volumn 286, Issue 5443, 1999, Pages 1335-1337

  Myneni, S C B ^a,b   Brown, J T ^a   Martinez, G A ^c   Meyer Ilse, W ^a  

^a LAWRENCE BERKELEY NATIONAL LABORATORY   (United States)

^b PRINCETON UNIVERSITY   (United States)

^c UNIVERSITY OF PUERTO RICO RIO PIEDRAS   (Puerto Rico)

Author keywords

[No Author keywords available]

Indexed keywords

HUMIC ACID; IMAGING METHOD; ORGANIC GEOCHEMISTRY; SOIL; WATER;

ARTICLE; BIOTRANSFORMATION; CARBON DIOXIDE FIXATION; CHEMICAL ANALYSIS; CHEMICAL STRUCTURE; HUMIC SUBSTANCE; IONIC STRENGTH; PH; PRIORITY JOURNAL; SEDIMENT; SOIL;

EID: 0032719474     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.286.5443.1335     Document Type: Article

References (23)

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9. 3 solution. The solid concentration in the experiments varied between 1 and 5 g of mineral per liter.
10. 4 windows (thickness, 100 nm), and this entire assembly was placed at the focal point of the zone plates. Small changes in the concentration of soluble species may occur in samples because of water evaporation losses during imaging. To prevent such changes, we collected images immediately after they were placed in the holder. The chemical conditions reported here represent samples in the initial stages. Typically, the x-ray exposure to the sample varied from a few seconds to 60 s. The natural organic did not show any visible damage or modifications under these exposure times or after several exposures. For more information on the x-ray microscope of LBNL, see work by W. Meyer-Ilse et al., Synchrotron Radiat. News 8, 29 (1995). Descriptions of x-ray spectromicroscopy are available in work by G. Schmahl et al., Optik 93, 95 (1993); J. Kirz, C. Jacobson, M. Howells, Q. Rev. Biophys. 28, 33 (1995); and J. Thieme et al., X-ray Microscopy and Spectromicroscopy (Springer, Berlin, 1998).
11. 4 windows (thickness, 100 nm), and this entire assembly was placed at the focal point of the zone plates. Small changes in the concentration of soluble species may occur in samples because of water evaporation losses during imaging. To prevent such changes, we collected images immediately after they were placed in the holder. The chemical conditions reported here represent samples in the initial stages. Typically, the x-ray exposure to the sample varied from a few seconds to 60 s. The natural organic did not show any visible damage or modifications under these exposure times or after several exposures. For more information on the x-ray microscope of LBNL, see work by W. Meyer-Ilse et al., Synchrotron Radiat. News 8, 29 (1995). Descriptions of x-ray spectromicroscopy are available in work by G. Schmahl et al., Optik 93, 95 (1993); J. Kirz, C. Jacobson, M. Howells, Q. Rev. Biophys. 28, 33 (1995); and J. Thieme et al., X-ray Microscopy and Spectromicroscopy (Springer, Berlin, 1998).
12. 4 windows (thickness, 100 nm), and this entire assembly was placed at the focal point of the zone plates. Small changes in the concentration of soluble species may occur in samples because of water evaporation losses during imaging. To prevent such changes, we collected images immediately after they were placed in the holder. The chemical conditions reported here represent samples in the initial stages. Typically, the x-ray exposure to the sample varied from a few seconds to 60 s. The natural organic did not show any visible damage or modifications under these exposure times or after several exposures. For more information on the x-ray microscope of LBNL, see work by W. Meyer-Ilse et al., Synchrotron Radiat. News 8, 29 (1995). Descriptions of x-ray spectromicroscopy are available in work by G. Schmahl et al., Optik 93, 95 (1993); J. Kirz, C. Jacobson, M. Howells, Q. Rev. Biophys. 28, 33 (1995); and J. Thieme et al., X-ray Microscopy and Spectromicroscopy (Springer, Berlin, 1998).
13. 4 windows (thickness, 100 nm), and this entire assembly was placed at the focal point of the zone plates. Small changes in the concentration of soluble species may occur in samples because of water evaporation losses during imaging. To prevent such changes, we collected images immediately after they were placed in the holder. The chemical conditions reported here represent samples in the initial stages. Typically, the x-ray exposure to the sample varied from a few seconds to 60 s. The natural organic did not show any visible damage or modifications under these exposure times or after several exposures. For more information on the x-ray microscope of LBNL, see work by W. Meyer-Ilse et al., Synchrotron Radiat. News 8, 29 (1995). Descriptions of x-ray spectromicroscopy are available in work by G. Schmahl et al., Optik 93, 95 (1993); J. Kirz, C. Jacobson, M. Howells, Q. Rev. Biophys. 28, 33 (1995); and J. Thieme et al., X-ray Microscopy and Spectromicroscopy (Springer, Berlin, 1998).
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23. S.C.B.M. dedicates this paper in memory of his co-author, Werner Meyer-Ilse. The authors thank T. K. Tokunaga, S. M. Benson, G. E. Brown, G. Sposito, S. J. Traina, and P. Maurice for helpful discussions and reviews of the manuscript and A. Lucero for help with the image processing. The research is funded by the Laboratory Directed Research and Development program of LBNL and by the Basic Energy Sciences (Geosciences) program of the U.S. Department of Energy.