The effect of mechanical deformation on the barrier properties of rubbers and LLDPE geomembranes was analyzed from both an experimental and a theoretical perspective In the experimental approach, an apparatus for studying the permeation of organic solvents through mechanically deformed polymeric materials was custom built and tested. The apparatus consisted of a biaxial membrane stretching device and a modified ASTM F739 permeation cell. Capillary gas chromatography was used as the analytical technique to measure, in real time, the concentration of organic compounds at the downstream side of the membrane. The equipment was used to monitor in real time the permeation of mixtures of organic liquids through rubbers and linear low-density polyethylene membranes at several elongations From the theoretical perspective, a mathematical model that modifies Fick's law of diffusion including a stress related diffusion coefficient was developed and tested. The model uses a linear viscoelasticity approach to account for the effect of stress on the transport of the solvents through the deformed membrane. The model yields satisfactory agreement with the experimental data and provides an indication of whether the transport process is diffusion or stress controlled A decrease in breakthrough times with elongation was observed for the permeation of acetone, hexane and mixtures thereof through rubber membranes at several degrees of uni and biaxial elongation. The decrease in breakthrough times was related to a decrease in thickness of the membrane as it was elongated. An increase in the steady state permeation rate of acetone and hexane with elongation was also observed. This increase in permeation rates was associated with the solubility of acetone and hexane into the rubber membranes. In addition, stress enhanced transport as well as facilitated transport of acetone through butyl rubber membranes was observed A decrease in breakthrough times with elongation was observed for the permeation of methylene chloride, trichloroethylene and mixtures thereof through LLDPE geomembranes. The decrease in breakthrough times was related to a decrease in thickness of the membrane as it was elongated. An increase in permeation rates with elongation was also noted and related to the solubility of the solvents into the geomembranes / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

Ene reactions of singlet oxygen or nitroso compounds with electron-rich olefins have been studied for many years, it is still the subject of controversy. Previous work in our group supported the acylaziridine-N-oxide intermediacy in the intramolecular ene reaction of nitrosocarbonyl alkenes. In part 1, the efforts to prepare the acylaziridine-N-oxides by a different approach have been discussed. A general and efficient process for the synthesis of cyclic iodocarbamates and bicyclic aziridinocarbamates is presented Cinncassiol D1 is a diterpene isolated from the water extracts of Cinnamomum Cassia Blume exhibiting anti-complement and anti-allergic activities. The pentacyclic cinncassiol D1 structure contains a polyhydroxy 5-6-5 cis fused ring system, which is unique to the family of diterpenes. In part 2, the synthesis of a precursor to cinncassiol D1 with a 5-6-5 cis fused ring system is accomplished through a transannular Diels-Alder reaction of a 12-membered trienelactone. Preparation of this trienelactone is discussed in detail, including l,4-conjugate addition, hydrostannation, Arbuzov rearrangement, Stille coupling, EDC activated esterification and intramolecular Horner-Wadsworth-Emmons reaction / acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

acase@tulane.edu

Nitrosocarbonyl compounds are reactive intermediates, which are generated only in situ. Several of these reactive intermediates have been used in natural product syntheses; but, little mechanistic work has been reported. We have generated several of these nitrosocarbonyl compounds in order to study the mechanistic aspects of their intramolecular ene reaction The reactivity of the nitrosocarbonyl compounds have been compared to other systems like singlet oxygen and triazolinediones. Our studies support the fact that the intramolecular ene reactions of nitrosocarbonylalkenes proceed via an analogous intermediate as that of other systems like singlet oxygen and triazolinediones / acase@tulane.edu

acase@tulane.edu

The relative contribution of internal and external factors to the experience of menstruation was assessed in this study. To ascertain external effects, comparisons were made between postovulation and menstruation cycle phases, both characterized by low levels of hormonal activity. Comparisons between premenstruation (typified by hormonal fluctuation) and postovulation allowed for assessment of the influence of internal factors on behavior. Additionally, to determine if physiological factors prevail over social/psychological factors, comparisons were made between premenstruation and menstruation, two hormonally dissimilar states overtly distinguished by menstrual flow. The 150 subjects were administered the Tennessee Self Concept Survey (TSCS), the Mood Adjective Checklist (MACL), a Semantic Differential measure, and Ziller's self-other orientation task on four separate occasions. College females' (n = 89) menstrual cycle phase was covertly determined by the Billings' Ovulation Method. In addition, self concept was experimentally manipulated to establish the sensitivity of these instruments. Male subjects (n = 61) were tested separately; their data provided support for the self-concept manipulation as well as for the cover story control. All subjects viewed menstruation as having considerable debilitating influence on women's physical, emotional, and mental activity. Catholic females and Jewish males viewed the effects of menstruation to be most serious, a relationship positively corelated with religiosity. In addition, Semantic Differential data indicated that menstruation is viewed negatively, a perception more exaggerated during menstruation than at other times. Generally, long menses (> 5 days) females showed less behavioral fluctuation than did short menses ((LESSTHEQ) 5 days) subjects. These two groups differed with regard to mood, self concept, and social orientation during the cycle, indicating that they should be considered separately when discussing the effects of menstruation on behavior. Some support was provided for the hypothesis that experience of menstruation is influenced by social conditioning. Differences in self concept were found which suggest that menstruating females experience conflict and confusion. Additionally, women tended to interact less during menstruation than during postovulation. They also reported being closer to boyfriends premenstrually than postovulatorily. Mood changes appeared to be more dependent on physiological factors. Specifically, menstruating women experienced an increase in the moods subsumed under the factor, Euphoria, when compared to premenstruation. Females also reported feeling more tired and inactive premenstrually. Perhaps these mood changes reflect physiological influences more than social influences. As such, premenstrual hormone fluctuations may influence moods more strongly than social factors during menstruation. The self-concept manipulation provided support for the sensitivity of the instruments employed in this study. Moreover, menstruating women in the high self-concept manipulation group showed the greatest influences of the manipulation on the TSCS and MACL measures. These females more positively reevaluated themselves in comparison to postovulatory subjects. The low self-concept manipulation had least effect on menstruating females, indicating that perhaps poor performance simply confirmed their expectations. The results of this study lend support to the notion that the experience of menstruation is mediated by external factors. Thus, while the influence of hormones on behavior is important, its effect does not appear to be as pervasive as once thought / acase@tulane.edu