How does one react when an important in-group does not value another important identity? This question may be answered by role conflict theory. Role conflict occurs when one role interferes or otherwise overlaps with another role (Hecht, 2001). Both conflicting roles must be salient for role conflict to occur. The present research investigates the role conflict Blacks may experience between their racial identity and their identity as a business professional. We hypothesized that role conflict would produce increased stress as measured by blood pressure. Aspiring Black professionals in the present study were asked to give advice regarding self-presentation to a target interviewing at a conservative law firm. The target was either Black with dreadlocks (High Role Conflict: HRC) or White with multiple piercings (Low Role Conflict: LRC). Pre-testing revealed that neither target conformed to normative standards of business presentation. Blood pressure was assessed during the advice task as a measure of participants' stress responses. Afrocentricity as well as other potential moderators were also considered. Contrary to predictions, participants in the HRC condition exhibited lower blood pressure readings than participants in the LRC condition. This effect was marginally moderated by Afrocentrism. That is, also not consistent with predictions, the blood pressure of participants in the low conflict group increased as a function of Afrocentrism. Potential explanations of these effects are discussed / acase@tulane.edu

Pediatric panic symptoms are associated with functional impairments such as school refusal and are highly co-morbid with other psychological problems. Trauma exposure and panic symptoms have been linked, although this relationship is not well understood in children and adolescents. It was hypothesized that anxiety sensitivity (AS; fear of anxiety-related arousal) would mediate the relationship between hurricane exposure and panic symptoms and that the relationship between anxiety sensitivity and panic would be strongest among females. Data were collected from youth living in the New Orleans area at two time points following Hurricane Katrina (5-8 months and 17-18 months afterwards). At time one (T1), AS predicted panic symptoms beyond hurricane exposure. Anxiety sensitivity moderated the relationship between hurricane exposure and panic at T1. AS at T2 predicted panic symptoms at T2 beyond hurricane exposure, T1 panic, and AS at T1. Results extend knowledge in the area of pediatric trauma responses and raise new possibilities to be investigated by future researchers and clinicians / acase@tulane.edu

Previous studies from this laboratory have shown that acute administration of morphine induces translocation of protein kinase C (PKC) betaII in a subset of neurons in rat brain (Garcia and Harlan 1995). As these neurons do not express mu opioid receptor (MOR), trans-synaptic activation is likely. Other studies have suggested a role for serotonergic neurons of periaqueductal grey (PAG) and dorsal raphe (DR) in morphine-mediated c-Fos expression (Frankel et al 1999) and PKCbetaII translocation in rat forebrain (Harlan et al 2004), as neurons of lateral PAG/DR express MOR. The studies of this dissertation were carried out to attain better understanding of the circuitry involved in morphine-mediated translocation of PKCbetaII in layer V pyramidal neurons of parietal cortex Fluorescence immunocytochemistry was used to demonstrate that a population of pyramidal neurons in parietal cortical layer V express both PKCbetaII and 5HT2A receptors. Since projections from the PAG/DR to these cortical neurons are serotonergic, it is possible that morphine-mediated translocation of PKCbetaII occurs subsequent to activation of 5HT2A receptors. It was then demonstrated that infusion of MOR antagonist, beta-funaltrexamine, into lateral PAG significantly inhibits morphine-mediated translocation. These data suggest that MOR in the PAG/DR are involved Systemic administration studies showed that DOI, a 5HT2A/2C receptor agonist, significantly blocks morphine-induced translocation. Ketanserin, a 5HT2A>2C receptor antagonist, induces PKCbetaII translocation, but effectively blocks morphine-mediated translocation. SB242084, a 5HT 2C receptor antagonist, partially blocks the effects of morphine. Direct infusion of DOI into lateral PAG inhibits morphine-mediated PKCbetaII translocation, and infusion into layer V parietal cortex has no effect on it. Infusion of ketanserin into lateral PAG stimulates translocation, but infusion into parietal cortical layer V inhibits it. Behavioral studies demonstrate that DOI, ketanserin, and SB242084, all affect morphine-mediated translocation. These studies collectively demonstrate that systemic morphine administration activates complex serotonergic circuitry that communicates information from lateral PAG to layer V parietal cortex, most likely through activation of 5HT2A and 2C receptors in the cortex The findings of this dissertation are significant for further understanding morphine and its function in the brain, and are relevant in further understanding how morphine modulates its effects along serotonergic neural circuitry / acase@tulane.edu

An early late Campanian transgressive lag, a 'shark tooth bed', in the local base of the Demopolis Formation overlying the Coffee Formation at the Frankstown site in Prentiss County, northeastern Mississippi, reveals a diverse vertebrate fauna of fragmentary remains pertaining to a wide variety of habitats of the northern Mississippi Embayment. By comparing the Frankstown taxa to those of less mixed faunas elsewhere in America, it is possible to separate the large primary shallow-water marine fauna from the smaller secondary deep-water marine, estuarine, fluviatile and terrestrial faunas mixed with it. The site includes 53 taxa---the most diverse Cretaceous vertebrate fauna known from Mississippi, including a chimaeroid, 13 sharks, 5 rays, 15 bony fish, 6 turtles, a lizard, 5 mosasaurs, a plesiosaur, 2 crocodilians, and 4 dinosaurs. Many of these (26) are new records for the state. A review of the 42 known Mississippi Late Cretaceous vertebrate taxa not present at the site is also included, 26 of which are also new records for the state. The deep-water (pelagic) marine fauna was likely washed inshore by storms, but the other secondary faunas were probably reworked from underlying beds. By separating the various faunas of a diverse transgressive lag assemblage, a broad overview of the paleoecology of the area can be obtained from a single site. Vertebrate faunas from the base of a stratigraphic sequence are fundamentally different in nature from those of the deep-water marine (maximum transgression) middle part of a sequence, and not, as has been thought, just a poorly preserved high-energy version of the well-preserved low-energy middle sequence fauna Based on X-ray diffraction analyses done for this study, it is argued that, in an early stage of lag formation, unstable phosphate was leached from the vertebrate material of the lag, and redeposited as a more stable form in wood, rip-up clasts, and steinkerns Contrary to previous work, it is shown that the shallow-water marine vertebrate fauna of the American Cretaceous changed little through that time---there was no major faunal change after the Turonian / acase@tulane.edu

Experimental results of the pulsed laser ablation and thin film deposition of titanium carbide and silicon carbide by pulsed laser deposition (PLD) are presented. PLD takes place by evaporation of a target sample composed of the desired film material, ejection and transfer in the gas phase, and deposition onto a substrate. Films thus grown benefit from the kinetics of the laser generated plume as well as from the high ion flux at the substrate. A major impediment to the PLD process is the contamination of films by molten and/or solid material ejected during ablation. Experimental parameters determine which contaminant is produced. This work presents two methods designed for film improvement by incorporating an electric field to the process. The first technique diverted a portion of the ionic plume component away from the trajectories of large particulates also generated during the laser-target interaction. The second technique involved the generation of an electric discharge across the laser generated plasma prior to deposition. The current across the plasma/plume initiates collisions in the plume that effectively break down the solid contaminants. Three laser pulse durations were used for material evaporation, employing long nanosecond pulses (Nd:YLF, 10 mJ, 250 ns), short nanosecond pulses (Nd:YAG, ∼3.5 ns) and femtosecond pulses (Ti:Sapphire, ∼150 fs). Included are gas phase studies using mass spectrometry, Langmuir ion probes, and deposition monitors that allowed the relative ion yields as well as their kinetics to be measured. The deposits were examined topographically by scanning electron and atomic force microscopies (SEM and AFM, respectively), and chemically by X-ray photoelectron spectroscopy (XPS) / acase@tulane.edu

Disease states such as acute respiratory distress syndrome and acute lung injury are characterized by pulmonary airway fluid occlusion and pulmonary surfactant insufficiency. Mechanical ventilation is used to restore airway patency, although this may result in ventilator induced lung injury. The goal of this dissertation is to investigate pulsatile ventilation waveforms in an idealized model of pulmonary airway reopening wherein the migrating semi-infinite bubble periodically retracts during reopening, termed retrograde motion. Such waveforms may redistribute surfactant along the air-liquid interface and reduce damage during airway reopening. We use computational and experimental techniques to explore the physicochemical hydrodynamic interactions that occur in this system We utilize the boundary element method to computationally investigate a model of airway reopening wherein a semi-infinite bubble migrates with both mean and sinusoidal velocity components through a fluid-occluded rigid tube. We find that the temporally- and spatially-dependent pressure gradient ∂tau n/∂z, the mechanical stimulus implicated in airway epithelial damage, increases significantly during retrograde bubble motion. During moderate oscillations large ∂tau n/∂z is confined to localized wall regions. However, at high frequencies and amplitudes a greater wall area is exposed to large ∂taun/∂z due to repeated passages of the bubble tip We experimentally investigate this system using micro-particle image velocimetry and shadowgraphy to measure the time-dependent velocity fields and bubble shapes in capillary tubes. A computer-controlled translating microscope stage and a suite of post-processing algorithms allow us to compute the ensemble-averaged bubble shape and velocity field at many points in the pulsatile cycle. We observe that Infasurf, a clinical pulmonary surfactant, blunts the bubble tip during pulsatile flows and significantly modifies the microscale flow field in the region of the tip due to physicochemical interactions Finally, we combine experimental and computational investigations to elucidate transport processes using Finite-time Lyapunov exponent (FTLE) analysis. In both cases we find that temporally-dependent Lagrangian coherent structures (LCS) demarcate the boundary between fluid advected upstream into the residual film and fluid advected downstream of the bubble tip. FTLE analysis of the measured velocities show increased mobility of the LCS in the presence of Infasurf, and may therefore elucidate the increase in surfactant transport during pulsatile ventilation / acase@tulane.edu

Experimental results from the pulsed laser ablation of carbon resulting in the formation of carbon toroids and carbon tubular constructs are presented. The toroids in this work are compared to the carbon-based toroids (CBTs) from fullerenes reported in 2005 and the results are reported. The mechanism behind the formation of carbon toroids and carbon tubular constructs are discussed based on the evidence obtained. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) clearly identifies toroidal shaped structures as well as carbon tubular constructs Some preliminary/interesting results from external electric field studies as applied to carbon tubular constructs experiments are presented. Profilometer studies indicate a loss of material ejection in the ablation plume / acase@tulane.edu

For some families of one-dimensional locally infinitely divisible Markov processes xet 0≤t≤T with frequent small jumps, large deviation expansions for expectations are proved: as epsilon ↓ 0 Ee expe-1F xe =expe -1Ff0 -Sf0 0≤i≤ s/2Ki˙ei+o&parl0; es/2&parr0; where s is a positive integer, S is the normalized action functional, constants Ki are expressed through derivatives of the smooth functional F, and &phis;0 is the unique maximizer of F -- S The proof of above large deviation expansions relies on asymptotic expansions for expectations of a smooth functional G of stochastic processes etaepsilon = epsilon--1/2(xi epsilon -- &phis;0) : as epsilon ↓ 0 EeGhe =EGh +e1/2EA1Gh +˙˙˙+es/2EAsG h+o&parl0;es/2&parr0; for some Gaussian diffusion eta and suitable differential operators Ai / acase@tulane.edu

Photoinduced energy transfer plays an important role in natural processes such as photosynthesis. In the natural photosynthetic process, the pigment molecules namely chlorophyll absorb the light from the sun. Excitation energy then migrates from one chlorophyll molecule to another unidirectionally in an array and ultimately reaches the reaction center where charge separation occurs. In addition to its importance in natural phenomena, photoinduced energy transfer finds application in varied fields such as solar energy harvesting, sensors, information transfer and molecular electronics Transition metal complexes are a useful class of 'chromphores' and have been extensively used for light harvesting applications. The metal imine complexes (i.e. py(pyridine), bpy(2,2'-bipyridine), tpy(2,2':6',2'-terpyridine) of Ru(II), Os(II), Re(I) and Ir(III) have desirable properties that make them attractive for these applications. Compared to 2,2'-bipyridine-type complexes, 2,2':6',2'-terpyridine(tpy)-type complexes have been much less thoroughly examined, because the weak ligand field of tpy-type ligands results in a weak emissive and short-lived excited states of their complexes. However, tpy-type complexes have geometrical advantages, which are non-chiral and could lead to linear structures upon introduction of substituents at 4'-position of tpy. The goal of Chapter 2 has been to study ligand-ligand triplet energy transfer in tetrametallic Ru(II) terpyridyl phenylene vinylene complexes. Synergizing the properties of Oligo(1,4 phenylene-vinylene or OPV) and terpyridine symmetric and unsymmetric Ru(II) tetrametallic complexes have been synthesized. Excitation energy migration from an excited state localized on the tpvpvpt ligand to the tpvp(OR)vpt ligand in the heterometallic tetramer was monitored using transient absorption spectroscopy. The ligand tpvpvpt(terpyridyl phenyl vinyl phenyl vinyl phenyl terpyridine) is abbreviated in short as the 2 vinyl ligand(2V). Similarly tpvp(ORvpt) is abbreviated as 2vinyl alkoxy ligand (2V(OR) Chapter 3 also deals with ligand-ligand triplet energy transfer. In this case a bichromophoric complex with slightly different pi-pi* excited states has been synthesized. The complex in which ligand-ligand triplet energy was monitored is [(pyrtp)Ru(tpvp(OR)vpt)]2+(PF6) 2 (where pyr = pyrene; tpy = 2,2':6',2'-terpyridine). In order to observe energy transfer from the pyrene triplet excited state to the alkoxy phenylene vinylene triplet, the complexes were made as PMMA(Polymethymethacrylate) matrices Square-planar platinum (II) polypyridyl complexes represent an important class of compounds that possess a rich range of spectroscopic and photophysical properties. The aim was to synthesize simple and viable Pt(II) systems which would help us understand the structural and electronic factors that influence non-radiative relaxation. In this aspect we have synthesized a [(mpt)Pt(OH)] + complex. The spectroscopic and temperature-dependent luminescence lifetime studies of the hydroxo complex have been presented in Chapter 4 Chapter 5 deals with the synthesis, spectroscopic and temperature dependent luminescence lifetime studies of a series of tolyl terpyridyl platinum complexes (i.e) [mpt-Pt-L]x (Y) (L = Cl, MeCN, Py, DMASPy, PPh3 ); (x = 1 or 2); (Y = CF3SO3 or BF4) spanning the spectrochemical series. DMASPy is 4,[4-(Dimethyl amino)styryl pyridine)]. The ability to vary the L group affords the possibility of studying a series of related complexes / acase@tulane.edu

This research consists of two sections: Section one. Methodology studies on the synthesis of homoallylic amines and ethers The methodology for a mild, room temperature, InCl3 catalyzed allylation of N-tosylimines with allyltributyltin in THF was developed. Attempts were made to transform the homoallylic amines synthesized into other useful nitrogen-containing compounds A simple methodology for the preparation of homoallylic amines was developed via the activation of C-H bonds adjacent to nitrogen atoms. Using N, N-dimethyl aniline, optimized conditions were achieved using allyltributytin in the presence of 1, 4-dioxane, CuBr/InCl3 as catalysts and tert-butyl hydroperoxide (TBHP) as oxidant. A number of other amines were successfully investigated. The methodology was extended to the synthesis of homoallylic ethers Section two. Development of a novel isolation technique for aqueous indium-mediated Barbier-Grignard type allylation reactions Aqueous indium-mediated Barbier-Grignard type allylation reactions of aldehydes with perfluorinated allyl ether were conducted at 50°C. The products derived were purified directly from the aqueous reaction mixture using fluorous solid phase extraction (F-SPE). Under similar conditions, the methodology was extended to the allylation of other substrates included imines and simple sugars. Zinc and tin were also found to mediate the reaction, although less effectively than indium The methodology for a room temperature, indium-mediated Barbier-Grignard type allylation of aldehydes with 2-bromomethyl-acrylic perfluoroester was developed. After direct purification by fluorous solid phase extraction, the products derived were cyclized under mild, basic conditions to form alpha-methylene-gamma-butyrolactones. The methodology was successfully extended to the allylation of glycoaldehyde, a water-soluble aldehyde The novel separation technique developed can potentially be used to overcome some of the challenges associated with purifying products directly from aqueous reaction mixtures, especially reactions involving carbohydrates. Additionally, all substrates were allylated without the need to protect and deprotect reactive functional groups / acase@tulane.edu