Heterocyclic steroids prepared in our synthetic azasteroid program became leads to anabolic, antiandrogenic, anti-BPH, birth control, anti-inflammatory, antialdosterone, hypocholesterolemic, neuromuscular relaxant, antibacterial and antifungal drugs. The most promising of these derivatives were 4-azasteroids, first prepared in our program.
The more active azasteroid antibiotics were cholestane derivatives. They controlled growth of antibiotic resistant Gram-positive bacteria, molds and yeasts, often at concentrations as low as one part per million. This presentation will describe the first syntheses and antimicrobial evaluations of novel 4-aza-20[alpha]-aminopregnanes. They were synthesized from pregnenolone and/or progesterone. They will be compared with previously reported active 4-azasteroids.
EVALUATION OF LIGHT SCATTERING PARTICLES AS A MEANS TO INCREASE PATH LENGTH FOR ABSORPTION EXPERIMENTS. In Cho, Yoon Cho, and Jon Thompson, Department of Chemistry, Troy State University, Troy, AL 36082.
We have evaluated inclusion of nanometer sized (109 - 3170 nm) polystyrene particles within the standard sample and reference cells of a dual beam spectrophotometer as a means to increase optical path length through the absorbing sample. It is believed that photons are multiply scattered as they "diffuse" through the highly turbid sample prior to emerging from the optical cell and being detected. These multiple scatter events lead to a net increase in average pathlength from the standard 1 cm commonly employed to path lengths approaching 10 cm when a high concentration of 109 nm particles are used as the scattering material. This increase in path length should allow for more sensitive detection of a variety of absorbing species in solution.
DESIGN AND IMPLEMENTATION OF AN INEXPENSIVE, PORTABLE CAPILLARY ELECTROPHORESIS (CE) INSTRUMENT. Greg Anderson, Utkarsh Singh, and Jon Thompson, Department of Chemistry, Troy State University, Troy, AL 36082.
Over the past 20 years, capillary electrophoresis (CE) has emerged as a popular method for analytical separations of ions in solution due to the highly efficient separations and rapid analysis times the technique allows. The technique is based upon the differential migration of ions through a narrow bore (5 - 100 [micro]m) fused silica tube when under an applied electric field (10 - 30 kV). Despite the techniques utility, many Universities are unable to purchase commercially available CE instrumentation due to funding limitations. In our work, we have designed and developed an instrument for performing capillary electrophoresis separations on a budget of ~ $500. Our instrument is constructed from a modified student microscope to allow for on-column fluorescence detection using a light emitting diode (LED) as an excitation source. An inexpensive DC-DC converter is used to provide high voltage for the electrophoresis separation. We have applied our instrument to the determination of riboflavin and flavin mononucleotide (FMN) in solution. It has been found that our instrument is capable of detecting 20.5 [micro]g/mL of riboflavin and 21.4 [micro]g/mL of FMN in solution.
QUANTITATIVE ANALYSIS OF OIL ABSORPTION BY GRAFTED BAGASSE IN SIMULATED OCEAN ENVIROMENT. Mikita R. Brown, Veronica E. Blackman, and Adriane G. Ludwick, Tuskegee University, Tuskegee AL 36088.
Grafted bagasse is an environmentally safe oil absorbing material composed of compressed sugar crane reacted with the following compounds:10% stearic acid, 4% zinc oxide, 2% t-butylamine, 2% sodium hydroxide, and 1% ammonium carbonate. The previous work of Mohamed Abdulla proved that grafted bagasse absorbs oil from pure water. The purpose of this experiment was to conduct a quantitative analysis of the absorbing capacity of bagasse from pure water and simulated ocean environments using various salt water concentrations: 5% NaCl and 10% NaCl. Quantitative analysis was performed using gas chromatography; column conditions were set for 2000C and run for 25 minutes. A calibration curve was formatted using known concentrations of oil vs. water, and two replicates were evaluated to determine the amount of oil present in each extraction. Extractions were done by separating oil volumes from water using ethyl ether, and oil volumes from bagasse using dichloromethane, to yield the following oil volumes: from ethyl ether extractions 30.0 +/- 0.12 ul, 29.7 +/- 0.09 ul, 30.5 +/- 0.54ul for pure water, 5% NaCl, and 10% NaCl samples respectfully, and in dichloromethane extractions 1.117 +/- 0.035 mL, 1.431 +/- 0.016 mL, 1.401 +/- 0.024 mL of oil was absorbed from bagasse from pure water, 5% NaCl, and 10% NaCl samples respectfully. Based on this data, grafted baggase expresses a nearly equal absorbing capacity in both pure and salt-water environments.
GALVANIC PLATING OF ZINC ONTO COPPER, M. B. Moeller, A. N. Keenum and C. R. South, Dept. of Chemistry and Industrial Hygiene, Univ. of North Alabama, Florence, AL 35632.
Zinc metal will spontaneously plate from zinc solution onto copper metal in an electrochemical cell. The reaction is due to the reduced activity of zinc atoms on a copper surface compared to zinc atoms on a pure zinc surface. It was found that galvanic cells having pure zinc and pure copper electrodes in electrolytes containing zinc ions have electric potentials which vary with the pH of the electrolyte. Our study measured cell potentials of 0.74 V, 0.77 V and 0.95 V in solutions of pH 2.3, 4.7 and 14, respectively. The ultimate thickness of the zinc layer that deposits on a copper surface was determined by digesting samples in nitric acid and measuring the resulting concentrations of zinc and copper using atomic absorption and visible spectroscopy. Similar to the initial cell potentials, the thickness of zinc achieved varied with the pH of the electrolyte, with thicknesses of 0.028 mm, 0.038 mm and 0.059 mm deposited from solutions having pH 2.3, 4.7 and 14. By estimating the cell capacitance and measuring the initial rate of voltage increase after a jumper wire was removed, an estimate of initial reaction rates for galvanic cells were obtained. In pH 4.7 electrolyte, the initial rate of deposition of zinc was 1.5 X 1[0.sup.-13] mol c[m.sup.-2] [s.sup.-1]. The corresponding value in strongly alkaline solution was found to be 6.0 X 1[0.sup.-13] mol c[m.sup.-2] [s.sup.-1]. A laboratory exercise based on these experiments and suitable for General Chemistry Laboratory is posted at http://www2.una.edu/mmoeller.
|Printer friendly Cite/link Email Feedback|
|Publication:||Journal of the Alabama Academy of Science|
|Date:||Apr 1, 2004|
|Previous Article:||Biological Sciences.|
|Next Article:||Geography, forestry, conservation, and planning.|