958 resultados para Uptake of nitrogen
Resumo:
Mode of access: Internet.
Resumo:
Typewritten.
Resumo:
The purpose of the report is to evaluate baseline loadings of nutrients and sediment to the Mississippi River and the Ohio River from the state of Illinois and to identify the sources of those loads; also evaluated are baseline loadings of nutrients and sediments to the Illinois River from its tributaries.
Resumo:
Includes bibliographical references (p. 15-16).
Resumo:
Reprinted from the Astrophysical journal, v. 39, January, 1914.
Resumo:
"Reprinted from the New York medical journal, June, 1871."
Resumo:
Mode of access: Internet.
Resumo:
Bibliography: p. 29-30.
Nitrogen trichloride as a chlorinating agent : the action of nitrogen trichloride on ethyl bromide /
Resumo:
Typescript.
Resumo:
The rms2 and rms4 pea ( Pisum sativum L.) branching mutants have higher and lower xylem-cytokinin concentration, respectively, relative to wild type (WT) plants. These genotypes were grown at two levels of nitrogen (N) supply for 18 - 20 d to determine whether or not xylem-cytokinin concentration (X-CK) or delivery altered the transpiration and leaf growth responses to N deprivation. Xylem sap was collected by pressurising de-topped root systems. As sap-flow rate increased, X-CK declined in WT and rms2, but did not change in rms4. When grown at 5.0 mM N, X-CKs of rms2 and rms4 were 36% higher and 6-fold lower, respectively, than WT at sap-flow rates equivalent to whole-plant transpiration. Photoperiod cytokinin (CK) delivery rates ( the product of transpiration and X-CK) decreased more than 6-fold in rms4. Growth of plants at 0.5 mM N had negligible (< 10%) effects on transpiration rates expressed on a leaf area basis in WT and rms4, but decreased transpiration rates of rms2. The low-N treatment decreased leaf expansion by 20 - 25% and expanding leaflet N concentration by 15%. These changes were similar in all genotypes. At sap-flow rates equivalent to whole-plant transpiration, the low N treatment decreased X-CK in rms2 but had no discernible effect in WT and rms4. Since the low N treatment decreased transpiration of all genotypes, photoperiod CK delivery rates also decreased in all genotypes. The similar leaf growth response of all genotypes to N deprivation despite differences in both absolute and relative X-CKs and deliveries suggests that shoot N status is more important in regulating leaf expansion than xylem-supplied cytokinins. The decreased X-CK and transpiration rate of rms2 following N deprivation suggests that changes in xylem-supplied CKs may modify water use.
Resumo:
The syntheses of the hexadentate ligands 2,2,10,10-tetra(methyleneamine)-4,8-dithiaundecane (PrN(4)S(2)amp), 2,2,11,11-tetra(methyleneamine)-4,9-dithiadodecane (BuN(4)S(2)amp), and 1,2-bis(4,4-methyleneamine)-2-thiapentyl)benzene (XyN(4)S(2)amp) are reported and the complexes [Co(RN(4)S(2)amp)](3+) (R = Pr, Bu, Xy) characterised by single crystal X-ray study. The low-temperature (11 K) absorption spectra have been measured in Nafion films. From the observed positions of both spin-allowed (1)A(1g) --> T-1(1g) and (1)A(1g) --> T-1(2g) and spin forbidden (1)A(1g) --> T-3(1g) and (1)A(1g) --> T-3(2g) bands, octahedral ligand-field parameters (10D(q), B and C) have been determined. DFT calculations suggest that significant interaction between the d-d and CT excitations occurs for the complexes. The calculations offer an explanation for the observed deviations from linearity of the relationship between Co-59 magnetogyric ratio and beta(DeltaE)(-1) (beta = the nephelauxetic ratio; DeltaE the energy of the (1)A(1g) --> T-1(1g) transition) for a series of amine and mixed amine/thioether donor complexes.
Resumo:
Polyethylcyanoacrylate (PECA) nanoparticles were prepared by interfacial polymerization of a water-in-oil microemulsion. Nanoparticles were isolated from the polymerization template by sequential ethanol washing and centrifugation. A nanocapsule preparation yielding the original particle size and distribution following redispersion in an aqueous solution was achieved by freeze-drying the isolated nanoparticles in a solution of 5% w/v sugar. The cytotoxicity and uptake of nanocapsules by dendritic cells was investigated using a murine-derived cell line (D1). PECA nanoparticles were found to adversely effect cell viability at concentrations greater than 10 mug/ml of polymer in the culture medium. In comparison to antigen in solution, cell uptake of antigen encapsulated within nanoparticles was significantly higher at both 4 and 37 degreesC. Following a 24 h incubation period, the percentage of cells taking-up antigen was also increased when antigen was encapsulated in nanoparticles as compared to antigen in solution. The uptake of nanoparticles and the effect of antigen formulation on morphological cell changes indicative of cell maturation were also investigated by scanning electron microscopy (SEM). SEM clearly demonstrated the adherence of nanoparticles to the cell surface. Incubation of D1 dendritic cells with nanoparticles containing antigen also resulted in morphological changes indicative of cell maturation similar to that observed when the cells were incubated with lipopolysaccharide. In contrast, cells incubated with antigen solution did not demonstrate such morphological changes and appeared similar to immature cells that had not been exposed to antigen.
Resumo:
Information on decomposition of harvest residues may assist in the maintenance of soil fertility in second rotation (2R) hoop pine plantations (Araucaria cunninghamii Aiton ex A. Cunn.) of subtropical Australia. The experiment was undertaken to determine the dynamics of residue decomposition and fate of residue-derived N. We used N-15-labeled hoop pine foliage, branch, and stem material in microplots, over a 30-mo period following harvesting. We examined the decomposition of each component both singly and combined, and used C-13 cross-polarization and magic-angle spinning nuclear magnetic resonance (C-13 CPMAS NMR) to chart C transformations in decomposing foliage. Residue-derived N-15 was immobilized in the 0- to 5-cm soil layer, with approximately 40% N-15 recovery in the soil from the combined residues by the end of the 30-mo period. Total recovery of N-15 in residues and soil varied between 60 and 80% for the combined-residue microplots, with 20 to 40% of the residue N-15 apparently lost. When residues were combined within microplots the rate of foliage decomposition decreased by 30% while the rate of branch and stem decomposition increased by 50 and 40% compared with rates for these components when decomposed separately. Residue decomposition studies should include a combined-residue treatment. Based on C-15 CPMAS NMR spectra for decomposing foliage, we obtained good correlations for methoxyl C, aryl C, carbohydrate C and phenolic C with residue mass, N-15 enrichment, and total N. The ratio of carbohydrate C to methoxyl C may be useful as an indicator of harvest residue decomposition in hoop pine plantations.