Current Search: Baker, Earl W. (x)
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- Title
- Pigment analysis of benthic and pelagic algae in Lake Okeechobee, Florida.
- Creator
- Winfree, Nancy, Florida Atlantic University, Baker, Earl W.
- Abstract/Description
-
Water samples from Lake Okeechobee, Florida have been analyzed in order to relate pigment fingerprints to temporal and spatial variations. Chemical taxonomic identification of predominant photoautotrophs was based on pigment profiles evolved from literature reports and analysis of specific cultures. Carotenoids and chlorophylls were analyzed using high performance liquid chromatography (HPLC) and ultra-violet visible spectra obtained with a photo diode array detector (PDA). Pigments were...
Show moreWater samples from Lake Okeechobee, Florida have been analyzed in order to relate pigment fingerprints to temporal and spatial variations. Chemical taxonomic identification of predominant photoautotrophs was based on pigment profiles evolved from literature reports and analysis of specific cultures. Carotenoids and chlorophylls were analyzed using high performance liquid chromatography (HPLC) and ultra-violet visible spectra obtained with a photo diode array detector (PDA). Pigments were identified by coincident matches of retention time and UV/Visible spectral properties. Chemical taxonomic identification was determined by comparison with known photoautotrophic pigment 'fingerprints'. Experimental results show pigment arrays indicative of chromophytes, chlorophytes and cyanophytes as well as photoautotrophic bacteria present in Lake Okeechobee. The lake was also found to be heterogeneous and dynamic in terms of pigment composition. Major pigment groups changed as a function of location in the lake and as a function of season. A greater pigment diversity was found to exist in the benthos due to the presence of degradation products. HPLC-PDA pigment analysis for chemotaxonomic typing of photoautotrophic communities is attainable and can be used as a rapid viable alternative to microscopic examination of plankton and epiphyte samples. Also, taxonomic typing of organic matter and photoautotrophic communities of sediments, including bacterial populations, can be accomplished using this method.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15261
- Subject Headings
- Plant pigments--Analysis, Photosynthetic pigments--Analysis, Freshwater algae, High performance liquid chromatography, Okeechobee, Lake (Fla)
- Format
- Document (PDF)
- Title
- Synthesis of thiadiazole- and diazepine-based acyclonucleosides with potential anticancer or antiviral activity.
- Creator
- Wang, Zhenling, Florida Atlantic University, Baker, Earl W.
- Abstract/Description
-
Cancer is a large group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled or checked, it results in death. Cancer is one of the leading causes of death in Western societies. In the United States, cancer is the second leading killer. However, many cancers can be cured if detected early and treated promptly. This paper analyzes the synthesis of thiadiazole- and diazepine-based acyclonucleosides with potential anticancer or antiviral...
Show moreCancer is a large group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled or checked, it results in death. Cancer is one of the leading causes of death in Western societies. In the United States, cancer is the second leading killer. However, many cancers can be cured if detected early and treated promptly. This paper analyzes the synthesis of thiadiazole- and diazepine-based acyclonucleosides with potential anticancer or antiviral activity.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14815
- Subject Headings
- Cancer, Antiviral agents, Nucleosides
- Format
- Document (PDF)
- Title
- Vanadyl and nickel geoporphyrin biodegradation study in high sulfur Monterey crude oils and Canadian tar sands.
- Creator
- Magnier, Clotilde Caroline, Florida Atlantic University, Baker, Earl W.
- Abstract/Description
-
Oil samples from the Monterey formation (California) and McMurray (Canada) formations have been analysed in order to relate bacterial biodegradation and metallo-porphyrins found in crude oils. The choice of samples was made according to biodegradation levels, in order to relate these processes with pigment degradation. Vanadyl and nickel petro-porphyrins were isolated by column chromatography, analyzed by Mass Spectrometry, and were correlated to maturity with DPEP to ETIO ratios and plots of...
Show moreOil samples from the Monterey formation (California) and McMurray (Canada) formations have been analysed in order to relate bacterial biodegradation and metallo-porphyrins found in crude oils. The choice of samples was made according to biodegradation levels, in order to relate these processes with pigment degradation. Vanadyl and nickel petro-porphyrins were isolated by column chromatography, analyzed by Mass Spectrometry, and were correlated to maturity with DPEP to ETIO ratios and plots of %DPEP vs. alkylation indices. Experimental data indicates that (1) biodegradation and maturity are two independent chemical processes, and (2) that biodegradation does not affect the vanadyl porphyrin profile, thus making them excellent indicators of pre-biodegradation thermal histories for the source bitumen.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14722
- Subject Headings
- Porphyrins--Biodegradation
- Format
- Document (PDF)
- Title
- HPLC separation and characterization of nickle geoporphyrins.
- Creator
- Zeng, Shaochuan, Florida Atlantic University, Baker, Earl W.
- Abstract/Description
-
HPLC separation of nickel geoporphyrin homologues and isomers has been markedly enhanced by a number of modifications of previously disclosed methods. A general, more efficient and reproducible method has been developed. A C18 3-micron reverse phase column with a programmed gradient binary mobile phase composed of solvent A which is methanol, water and solvent B which consists of methanol modified by the addition of powerful ligand; a consistent ratio of organic salt is added into this...
Show moreHPLC separation of nickel geoporphyrin homologues and isomers has been markedly enhanced by a number of modifications of previously disclosed methods. A general, more efficient and reproducible method has been developed. A C18 3-micron reverse phase column with a programmed gradient binary mobile phase composed of solvent A which is methanol, water and solvent B which consists of methanol modified by the addition of powerful ligand; a consistent ratio of organic salt is added into this solvent system to increase ionic strength of mobile phase. Straightforward HPLC separations of some marine sediment and oil shale extracts (nickel porphyrins) without demetallation have been successfully achieved. Most attention has been focused on Cowboy Gilsonite and Bakken oil-shale. Individual fractions have been collected and analyzed by UV-VIS, NMR, Mass spectrometry. Known compounds were used for co-chromatographic and spectroscopic reference.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14880
- Subject Headings
- High performance liquid chromatography, Porphyrins
- Format
- Document (PDF)
- Title
- High performance liquid chromatographic separation of sedimentary vanadyl porphyrins.
- Creator
- Huang, Xiaoxue, Florida Atlantic University, Baker, Earl W., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
A method of reversed phase HPLC gradient elution was developed and evaluated for the separation of vanadyl porphyrins. Separation was compared with the result of isocratic elution. It shows that gradient elution method is suitable for vanadyl porphyrin separation and better separation result can be obtained by gradient elution. Gradient elution improves the separation by changing the retention time of different components in the sample mixture and increases the difference of k' (capacity...
Show moreA method of reversed phase HPLC gradient elution was developed and evaluated for the separation of vanadyl porphyrins. Separation was compared with the result of isocratic elution. It shows that gradient elution method is suitable for vanadyl porphyrin separation and better separation result can be obtained by gradient elution. Gradient elution improves the separation by changing the retention time of different components in the sample mixture and increases the difference of k' (capacity factor). Vanadyl porphyrin samples Bakken 6362', Treibs #1 and Treibs #3 were analyzed by this method. Results correlate very well with the results of mass spectrometry analysis of these samples which have been done by some other workers.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/15094
- Subject Headings
- Porphyrins, High performance liquid chromatography
- Format
- Document (PDF)
- Title
- Senescent and early diagenetic changes in chlorophyll.
- Creator
- Li, Jie, Florida Atlantic University, Baker, Earl W., Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
- Abstract/Description
-
Aged unispecific cultures and environmental samples have been analyzed using HPLC-PDA in order to reveal chlorophyll-a degradation processes. Unispecific aging studies showed that alteration of chlorophyll occurred during senescence, and revealed that chlorophyll-a breakdown differs amongst various groups (i.e. species specificity). Sediment trap and sediment studies reveal that a variety of precursor chlorophyll-a derivatives are present, and that senescence and geochemistry, per se, overlap...
Show moreAged unispecific cultures and environmental samples have been analyzed using HPLC-PDA in order to reveal chlorophyll-a degradation processes. Unispecific aging studies showed that alteration of chlorophyll occurred during senescence, and revealed that chlorophyll-a breakdown differs amongst various groups (i.e. species specificity). Sediment trap and sediment studies reveal that a variety of precursor chlorophyll-a derivatives are present, and that senescence and geochemistry, per se, overlap strongly. Many of the reactions in the Treibs' scheme occur before and during deposition. Intracellular senescence and diagenetic pathways have been examined in this work. Comparison of aged unispecific cultures and environmental samples strongly suggests major in puts from the senescence pathway. The results further supports the concept "pyro" reaction (loss of the carbomethoxy group) fates chlorophyll diagenesis towards true DPEP compounds.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15455
- Subject Headings
- Chlorophyll, Algae, Plants--Aging, Diagenesis
- Format
- Document (PDF)