Beginning in the mid-1960's synthetic nucleoside derivatives of polyazaindolizines and polyazaindenes were studied for their anticancer activities. The most promising nucleosides for anticancer activity were pyrrolo-, imidazo-, and s-triazolo- pyrimidines and triazines. Syntheses of 1,2,4-triazolo 3,4c -1,2,4-triazine-7-oxide, 1,2,4-triazolo 3,4c pyrazine-7-oxide and 1,2,4-triazolo 2,3c pyrazine-7-oxide were achieved by the cyclization of the appropriate 3-hydrazinoazine N-oxide with diethoxymethyl acetate. When different one carbon cyclization agents react with the 3-hydrazinoazine-1-oxides they did not produce the expected polyazaindene-7-oxides. The reaction of formic acid with 3-hydrazino-1,2,4-triazine-1-oxide or 3-hydrazinopyrazine-1-oxide produced the 3-formylhydrazino derivatives. Similarly, the reactions of the 3-hydrazino -pyrazine-1-oxide and -triazine-1-oxide with benzaldehyde, acetic anhydride, or phenylisothiocyanate produced the 3-benzylideno, 3-acetyl, and 3-(4-phenylthiosemicarbizide) derivatives, respectively. The direct N-oxidation of imidazo 1,2a pyrazine with meta-chloroperbenzoic acid produced the imidazo 3,4c pyrazine-7-oxide. Proton nuclear magnetic resonance analyses of the polyazaindenes N-oxides has produced a set of shielding and deshielding parameters for ring protons. The mass spectral information obtained for the polyazaindene N-oxides suggests that the five membered ring of polyazaindene N-oxide has a decreased reactivity to electrophilic reagents when compared to the parent compound. The nitrogen-15 nuclear magnetic resonance spectra obtained for selected polyazaindenes were used to predict the percentage of contribution between two ground state resonance contributing structures. The nitrogen-15 nuclear magnetic resonance spectra of several substituted pyridine, pyrazine, pyrimidine and 1,2,4-triazine derivatives and their N-oxides were correlated with substituent contributions and ground state contributing structures. From this data, correlations between the nitrogen-15 chemical shifts and aromatic electron deficiency have been established.

Typescript / 298 leaves : ill. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The accumulation, chemical composition, and distribution of storage nitrogen in young peach trees (Golden queen on Elberta rootstock), and the importance of this stored nitrogen for new growth, were investigated in this thesis. In addition, the metabolic stability of constituents of the storage nitrogen of dormant peach trees was studied. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Physiology, Waite Agricultural Research Institute, 1966

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Dec. 4, 2007). PDF text: xi, 134 p. : ill. ; 6 Mb. UMI publication number: AAT 3271926. Includes bibliographical references. Also available in microfilm and microfiche formats.

Bibliography: leaves 170-191.

Bibliography: leaves 151-177.

Bibliography: leaves: 210-230.

No description available.

<p>One of the environmental problems today in seas, lakes and streams is eutrophication. This is often caused by nutrients such as phosphorus (P) and nitrogen (N) that leak from agricultural areas. A measure to partly prevent the nutrient discharge is to construct or restore wetlands.</p><p>In order to control the efficiency of nutrient reduction of existing wetlands in the county, the administrative board in Västra Götaland wants to find different criterias for reference wetlands. These reference wetlands should represent other wetlands and be used in future evaluations of reduction of nutrients and design of constructed wetlands.</p><p> </p><p>According to the administrative board in Västra Götaland the reference wetlands should have a catchment area of about 50 hectare consisting of at least 70 % arable land, to represent wetlands created to remove nutrients. The surface area should exceed 0,5 hectare and the inlet-nitrogen concentration should be around 5 mg N-1.</p><p>This report investigates nitrogen and phosphorus retention in two wetlands, Härstad and Åmot in the county of Västra Götaland, and if they fulfill the criteria of being a reference wetlands. In addition to this, a tracer study was performed in one of these wetlands with the purpose to study the hydraulic efficency.</p><p> </p><p>Neither the wetland in Åmot or Härstad achieves the guidelines of about 5 mg N l-1 in the incoming water. Therefore, they can be seen as inappropriate as reference wetlands according to their nitrogen retention. The wetland of Härstad, however, has significantly better N retention than the wetland of Åmot. Results from the report shows that N retention in the wetland of Härstad was relatively high not only due a higher N load, but also due to that N was largely in the form of NO3- facilitating efficient transformation of NO3- to N2 by denitrification bacteria. Nitrogen removal was much lower in the wetland in Åmot due to that N in incoming water was not in the form of NO3- and could therefore not be efficiently transformed to N2 by denitrification.</p><p>Incoming total phosphorus to the Härstad and Åmot wetlands exceeded 100 µg P l-1, which means "extremely high" tot-P concentrations according to environmental quality criteria from the Swedish Environment Protection Agency. Phosphorus load per wetland area was slightly higher in the wetland in Åmot than in the Härstad wetland. In spite of this, P retention per wetland area as well as relative P retention was clearly higher in the Härstad wetland. This can be explained by that P in incoming water to the Härstad wetland was to a larger degree than in the Åmot wetland bound to particles, facilitating P retention through sedimentation.</p><p>According to the tracer study, the Härstad wetland has a hydraulic efficency (λ) of about 0,13 which means it has a low hydraulic efficiency. The effective volume ratio (e) in Härstad was calculated to 18 % which means that the water has an inadequate spreading in the wetland, which is not good for the nutrient elimination in this wetland.</p><p>This study illustrates the difficulties in finding representative reference wetlands due to potential differences between wetlands in nutrient concentrations in incoming water, the degree that incoming P is bound to particles, the degree that incoming N is in the form of NO3-, and hydraulic efficiency.</p>

Poplar Bark Storage Proteins (BSP) are important in storing nitrogen (N) recovered from autumn-senescent leaves, and supply N for spring growth. Plants of Populus tremula x P. alba were transformed with a poplar BSP antisense cDNA fused to a double 35S promoter. Regenerated lines were screened for reduced BSP accumulation in short day photoperiod, and two lines were selected for further studies. Under long-day conditions, both BSP-antisense lines were characterized by larger leaves, longer internodes and slower growth rates, for a net shift in dry-matter partitioning from stem to leaf. Antisense lines also show reduced N concentration in leaf and stem tissue, and altered nitrate uptake. Grafting studies show that these effects on leaf and stem partitioning and N content are determined by the shoot genotype. These results indicate an important role of BSP in long day growth and partitioning. BSP-antisense plants did not show altered Nitrate Reductase activity, as determined by in vivo assay. Wild-type poplar plants were grown hydroponically on solutions of 0 to 30 mM nitrate, and NR activity determined on leaf, stem and root tissue. Leaf activity was >20x higher than root or stem, with the highest activity found in young expanding leaves. NR activity of both leaves and roots increased with N supply. During autumn, BSP-antisense leaves abscised earlier than the untransformed wt. Abscised wt leaves contained a higher proportion of pre-senescent N levels. Comparisons among ecotypes of P. deltoides and among clones of P. trichocarpa x P. deltoides demonstrated genetic variation in both time of BSP induction, and amount of BSP accumulation. In six P. deltoides ecotypes grown at a common site, time of maximum BSP mRNA was inversely correlated with latitude of origin. Eight to ten clones from each of six full-sib families of P. trichocarpa x P. deltoides were screened for SD BSP accumulation. Clonal differences in BSP accumulation were significant in 5 of 6 families, and clones with high BSP levels also had higher total stem N content. These results further confirm the importance of BSP in autumn N resorption. / Graduation date: 2000

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1983. / Vita. Includes bibliographical references (p. 268-279).