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- AMAUDRUZ, P, et al.
(författare)
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A REEVALUATION OF THE NUCLEAR-STRUCTURE FUNCTION RATIOS FOR D, HE, LI-6, C AND CA
- 1995
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Ingår i: NUCLEAR PHYSICS B. - : ELSEVIER SCIENCE BV. - 0550-3213. ; 441:1-2, s. 3-11
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Tidskriftsartikel (refereegranskat)abstract
- We present a re-evaluation of the structure function ratios F-2(He)/F-2(D), F-2(C)/F-2(D) and F-2(Ca)/F-2(D) measured in deep inelastic muon-nucleus scattering at an incident muon momentum of 200 GeV. We also present the ratios F-2(C)/F-2(Li), F-2(Ca)/F-2
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| 2. |
- Arneodo, M, et al.
(författare)
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Accurate measurement of F-2(d)/F-2(p) and R(d)-R(p)
- 1997
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Ingår i: NUCLEAR PHYSICS B. - : ELSEVIER SCIENCE BV. - 0550-3213. ; 487:1-2, s. 3-26
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented for F-2(d)/F-2(p) and R(d) - R(p) from simultaneous measurements of deep inelastic muon scattering on hydrogen and deuterium targets, at 90, 120, 200 and 280 GeV. The difference R(d) - R(p), determined in the range 0.002 < x < 0.4 at
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| 3. |
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| 4. |
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| 5. |
- Arneodo, M, et al.
(författare)
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The A dependence of the nuclear structure function ratios
- 1996
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Ingår i: NUCLEAR PHYSICS B. - : ELSEVIER SCIENCE BV. - 0550-3213. ; 481:1-2, s. 3-22
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Tidskriftsartikel (refereegranskat)abstract
- Results are presented for six nuclei from Be to Pb on the structure function ratios F-2(A)/F-2(C)(X) and their A dependence in deep inelastic muon scattering at 200 GeV incident: muon energy. The data cover the kinematic range 0.01 < x < 0.8 with Q(2) ran
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| 6. |
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| 7. |
- ARNEODO, M, et al.
(författare)
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THE STRUCTURE-FUNCTION RATIOS F-2(LI)/F-2(D) AND F-2(C)/F-2(D) AT SMALL-X
- 1995
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Ingår i: NUCLEAR PHYSICS B. - : ELSEVIER SCIENCE BV. - 0550-3213. ; 441:1-2, s. 12-30
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Tidskriftsartikel (refereegranskat)abstract
- We present the structure function ratios F-2(Li)/F-2(D) and F-2(C)/F-2(D) measured in deep inelastic muon-nucleus scattering at a nominal incident muon energy of 200 GeV. The kinematic range 10(-4) < x < 0.7 and 0.01 < Q(2) < 70 GeV2 is covered. For value
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| 8. |
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| 9. |
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| 10. |
- Spillmann, Dorothe, et al.
(författare)
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Characterization of a Novel Sulfated Carbohydrate Unit Implicated in the CarbohydrateCarbohydrate-mediated Cell Aggregation of the Marine Sponge Microciona prolifera
- 1995
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 270, s. 5089-5097
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Tidskriftsartikel (refereegranskat)abstract
- Species-specific cell reaggregation in the marine sponge Microciona prolifera is mediated by an adhesion proteoglycan. Two interactions are involved in the process: a Ca(2+)-dependent homophilic binding between proteoglycan molecules and a Ca(2+)-independent binding between the molecule and cells. Both interactions are mediated by the glycan moieties of the proteoglycan. The interaction of the proteoglycan with itself has been characterized as a carbohydrate-carbohydrate interaction of multiple low affinity sites. The monoclonal antibodies Block 1 and Block 2 raised against the purified aggregation proteoglycan and selected for inhibition of aggregation bind to these glycans. In a previous report the structure, [formula: see text] was assigned to the oligosaccharide reacting with Block 1 antibody (Spillmann, D., Hård, K., Thomas-Oates, J., Vliegenthart, J. F. G., Misevic, G., Burger, M. M., and Finne, J. (1993) J. Biol. Chem. 268, 13378-13387). By the technique of attaching the water-soluble acid-degraded fragments to a lipid carrier for immunochemical detection and by chemical, enzymatic and spectroscopic methods the structure, [formula: see text] was assigned to the oligosaccharide reacting with the aggregation-blocking monoclonal antibody Block 2. The structure, [formula: see text] was assigned to a major nonreactive oligosaccharide, which outlined the molecular requirements of antibody binding of the two aggregation-associated epitopes. These data demonstrate that two different functional sites with distinct structural characteristics and antibody reactivities are involved in the reaggregation of sponge cells, a model of carbohydrate-carbohydrate-mediated cell interactions.
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| 11. |
- Ulrich, G. A., et al.
(författare)
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Sulfur Cycling in the Terrestrial Subsurface : Commensal Interactions, Spatial Scales, and Microbial Heterogeneity
- 1998
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Ingår i: Microbial Ecology. - : Springer. - 0095-3628 .- 1432-184X. ; 36:2, s. 141-151
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Tidskriftsartikel (refereegranskat)abstract
- Microbiological, geochemical, and isotopic analyses of sediment and water samples from the unconsolidated Yegua formation in east-central Texas were used to assess microbial processes in the terrestrial subsurface. Previous geochemical studies suggested that sulfide oxidation at shallow depths may provide sulfate for sulfate-reducing bacteria (SRB) in deeper aquifer formations. The present study further examines this possibility, and provides a more detailed evaluation of the relationship between microbial activity, lithology, and the geochemical environment on meter-to-millimeter scales. Sediment of varied lithology (sands, silts, clays, lignite) was collected from two boreholes, to depths of 30 m. Our findings suggest that pyrite oxidation strongly influences the geochemical environment in shallow sediments ( 5 m), and produces acidic waters (pH 3.8) that are rich in sulfate (28 mM) and ferrous iron (0.3 mM). Sulfur and iron-oxidizing bacteria are readily detected in shallow sediments; they likely play an indirect role in pyrite oxidation. In consistent fashion, there is a relative paucity of pyrite in shallow sediments and a low 34S/32S-sulfate ratio (0.2ￜ) (reflecting contributions from 34S-depleted sulfides) in shallow regions. Pyrite oxidation likely provides a sulfate source for both oxic and anoxic aquifers in the region. A variety of assays and direct-imaging techniques of 35S-sulfide production in sediment cores indicates that sulfate reduction occurs in both the oxidizing and reducing portions of the sediment profile, with a high degree of spatial variability. Narrow zones of activity were detected in sands that were juxtaposed to clay or lignite-rich sediments. The fermentation of organic matter in the lignite-rich laminae provides small molecular weight organic acids to support sulfate reduction in neighboring sands. Consequently, sulfur cycling in shallow sediments, and sulfate transport represent important mechanisms for commensal interaction among subsurface microorganisms by providing electron donors for chemoautotrophic bacteria and electron acceptors for SRB. The activity of SRB is linked to the availability of suitable electron donors from spatially distinct zones.
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