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Full-Text Articles in Physical Sciences and Mathematics
Leaf Litter Processing In Aquatic Systems Two Variable Model, Boyd Jay Hanson
Leaf Litter Processing In Aquatic Systems Two Variable Model, Boyd Jay Hanson
Theses and Dissertations
The adequacy of the negative exponential model with one independent variable, days or accumulated time, as a descriptive equation for aquatic leaf litter processing was examined. The effect of adding a second independent variable, degree days or accumulated temperature, to the model was also examined. The two variable negative exponential model was shown to have at least two advantages over the single variable model. The two variable model adequately fits litter processing data for more cases than the single variable model. The expanded model also allows determination of rate coefficients for various temperature levels of the experiment rather than assuming …
High Pressure Liquid Chromatographic Methods For The Separations Of Derivatized Alpha-Keto Acids And Thiamine Phosphate Esters, Bruce Clark Hemming
High Pressure Liquid Chromatographic Methods For The Separations Of Derivatized Alpha-Keto Acids And Thiamine Phosphate Esters, Bruce Clark Hemming
Theses and Dissertations
Improved methods have been developed for separation of a-keto acid derivatives and for thiamine and its phosphate esters. Linear gradient reverse phase chromatography using ion-pair formation provides baseline resolution for a seven-component homologous series of a-keto acid dinitrophenylhydrazones having increasing carbon chain lengths. Branched-chain keto acids can also be separated. Aldehyde derivatives were examined as possible interfering compounds. Peak identification in biological material was confirmed for pyruvate by an enzymic peak shift technique. Monitoring near 365 nm permits low nanogram detection. Preliminary studies of keto acids in biological material illustrate the method's applicability. The same system with slight changes separates …
The Synthesis Of Novel Macrocyclic Multidentate Compounds From Dioxodioic Acids (1), R. Elliott Asay
The Synthesis Of Novel Macrocyclic Multidentate Compounds From Dioxodioic Acids (1), R. Elliott Asay
Theses and Dissertations
A series of novel macrocyclic multidentate crown compounds have been prepared from a series of dioxodioic acids. The dioxodioic acids were prepared by treating various oligoethylene glycols or amines with maleic, succinic, citraconic, and glutaric anhydrides. The crown compounds were then synthesized from the dioxodioic acid chlorides obtained from the diacids and various oligoethylene glycols or ethylene diamine.
A Photochemical Study Of S-Triazolo[4,3-B] Pyridazine And 3-Diazo-4-Oxo-3,4-Dihydroquinoline, John Timothy Carlock
A Photochemical Study Of S-Triazolo[4,3-B] Pyridazine And 3-Diazo-4-Oxo-3,4-Dihydroquinoline, John Timothy Carlock
Theses and Dissertations
When subjected to ultraviolet radiation in the presence of an alkene, s-triazolo[4,3-b]pyridazine (STP) undergoes an unusual 3 + 2 photocycloaddition wherein the alkene adds to the 1 and 8 positions of STP with concommitant N4-N5 bond cleavage yielding 5,6-disubstituted-6,7-dihydro-7-methylene (and 7-cyanomethyl)-5H-pyrrolo[1,2-b]-s-triazoles. Amides and esters of indole-3-carboxylic acid have been synthesized by a novel reaction employing the ultraviolet irradiation of 3-diazo-4-oxo-3,4-dihydroquinoline (QDA) in the presence of amines or alcohols respectively. QDA, when irradiated, is postulated to undergo an internal Wolff Rearrangement to Indole-3-ketene which can add any amine or alcohol to form the corresponding amide or ester in modest to good …
Real-Time Computer Optimized Scanning Potential Coulometry For Multi-Component Trace Analysis, Norman W. Petty
Real-Time Computer Optimized Scanning Potential Coulometry For Multi-Component Trace Analysis, Norman W. Petty
Theses and Dissertations
The instrumentation and methodology for real-time computer controlled scanning potential coulometry for multi-component trace analysis is described. The sensitivity limit was determined to be 10^-8 F for electrochemically reversible constituents. The sensitivity limit could be extended if measures were taken to compensate for the periodic signal found on the electrolysis current. Non-linear least squares curve fitting methods accurately resolved iron-platinum and silver-iron interferences to give accurate determinations for iron and silver. The resolving capability of this method was tested using theoretically generated scanning potential coulograms. The computer resolved sample constituents with a 1 to 100 concentration ratio and a formal …
The Dependence Of The Apparent Pk Of Ion Exchange Celluloses Of Ionic Strength, Paul Cyril Gillespie
The Dependence Of The Apparent Pk Of Ion Exchange Celluloses Of Ionic Strength, Paul Cyril Gillespie
Theses and Dissertations
Diethylaminoethyl cellulose was titrated with acid and base in various concentrations of NaCl. The pK values were determined from titration curves using a graphical technique. Two titratable groups were observed from the acid titration curve, a major and a minor group. The minor group, which represented 20% of the acid titration, was barely detectable in the base titration curve and had a salt-independent pK of 6.0. The pK of the major group was strongly salt-dependent and was approximately a linear function of log N NaCl. An equilibrium shift caused by the counter ion may explain the salt dependence. Hydrogen bonding …
Isolation, Purification, Scanning Electron Microscopy And Bacterial Dna Uptake Of Plant Protoplasts, Bronwyn G. Hughes
Isolation, Purification, Scanning Electron Microscopy And Bacterial Dna Uptake Of Plant Protoplasts, Bronwyn G. Hughes
Theses and Dissertations
Protoplasts were isolated from tobacco and barley leaves in sucrose or mannitol using commercially available cellulases and macerozymes. Barley growth and protoplast isolation and purification conditions were optimized so that protoplasts were obtained in high yields free of unwanted debris and organelles. A technique for processing barley and tobacco protoplasts for examination by scanning electron microscopy was developed in which protoplasts seem to have maintained their structural integrity. Barley and tobacco protoplasts took up 3H-B. subtilis DNA, 125I-B. subtilis DNA or 125I-M. luteus DNA as a linear function of time (0-6 hr) and DNA concentration (0-200 μg/ml). Up to 16 …
Certain Edaphic And Biotic Factors Affecting Vegetation In The Shadscale Community Of The Kaiparowits Area, Vane Orlan Campbell
Certain Edaphic And Biotic Factors Affecting Vegetation In The Shadscale Community Of The Kaiparowits Area, Vane Orlan Campbell
Theses and Dissertations
A study area on the southern extensions of the Great Basin cold desert (Kaiparowits Basin, Utah) was selected which has had varying amounts of disturbance. Areas with similar slope and exposure in the Shadscale community were sampled. At each site, soil samples were collected and percent sand, percent clay, percent silt, soluble salts, and hydrogen ion concentrations were measured. Cluster analysis based on percent frequency of the perennial species showed that eight groups or sub-communities were definable within the area sampled. Patterns within the vegetation were shown to be independent with the use of cluster analysis. Discriminant analysis on soil …