The present experiments explored the viability of a protocol involving artificial selection for recovery from cSNC across three selected generations. Preliminary evidence for the effects of selective breeding for the fast (H line), when compared to the slow (L line) and random (R line) lines, was reported. In addition, consistent changes in other behavioral tests were found exclusively for the H line during the third generation. Rats in the H strain showed smaller body size, lower water consumption, and less sensitivity for different sucrose solutions than rats in the other two strains. Moreover, animals in the H strain showed a different activity profile, with lower activity levels in the early portion of the session. Finally, autoshaping acquisition and extinction were slower for rats in the H line when compared to rats in the L and R lines.

Although several measures that evaluate disturbance in childhood attachment exist, few have been designed to assess attachment disturbances. The Beech Brook Attachment Disorder Checklist (BBADC) is one of the most promising measures of childhood attachment disorder that has been specifically designed to assess attachment disturbances, but further validation of the BBADC is necessary. Confirmatory and exploratory factor analyses and Rasch analysis of the BBADC items were conducted using a sample of adopted children. Exploratory analysis revealed five factors. Items on these factors were then subjected to Rasch analysis to determine unidimensionality of each factor and further refine the factors. Next, confirmatory factor analysis revealed that the five factor solution was a better fit to the data than the original two factor solution. Individual differences in the BBADC factors were examined. Finally, Child Behavior Checklist (CBCL) subscales were correlated with the five factors to determine convergent and discriminant validity.

Four experiments using the partial agonist D-cycloserine (DCS) were conducted to investigate the role of the N-methyl D-aspartate (NMDA) receptor in consummatory successive negative contrast (cSNC), an animal model of loss-induced anxiety. In Experiment 1, pretrial 11 and 12 administration of DCS (30 mg/kg) enhanced cSNC following the reward downshift from 32%-to-4% sucrose solution. In Experiment 2, posttrial 11 administration of DCS enhanced cSNC greatest at 30 mg/kg, following 32%-to-4%, and mildly following 32%-to-6%. In Experiment 3, DCS at 15 mg/kg and 60 mg/kg prolonged cSNC mildly (32%-to-4%). Experiment 4 suggested enhancement was not the result of conditioned taste aversion (CTA) to DCS (30 mg/kg); CTA to novel 4% solution failed to develop, compared to unpaired and saline controls. Results were interpreted to mean that activation of NMDA receptors via the glycine-modulatory site enhances the aversive memory associated with unexpected reward loss. Possible applications for therapeutic settings are discussed.

Compacts and composites were sintered under high pressure (2 GPa - 10 GPa) and high temperature (1400 - 2300 ° C) conditions. The compacts were sintered using nano-SiC powder, micron-diamond powder, and nano-diamond powder. Composites were sintered using the liquid infiltration method from nano-silicon powder and nano or micron diamond powder. Under the high pressure, high temperature conditions the silicon powder would melt and react with carbon from the diamonds to form a SiC matrix. The microstructure and strain of the composites and compacts was analyzed using X-ray diffraction analysis. The extended convolutional multiple whole profile fitting method was used to analyze the X-ray line profiles to determine average crystallite size, dislocation density, and planar fault probability. The apparent lattice parameter method was used to analyze strain. Below a certain pressure there was subgrain growth. However, at the higher pressures there was a reduction in crystallite size. In the SiC phase there was a correlation between predominate defect, dislocation or planar fault, and the crystallite size. The defect structure of the diamonds seemed to be dependent on the initial diamond powder used. At higher temperatures there was evidence of recovery and or recrystallization.

Small molecular clusters consisting of transition metals and carbon, which are the focus of the research, are important for their potential as astrophysically significant species and for the information they may provide about the structures and bonding mechanisms of larger transition-metal carbide structures, such as metallocarbohedrenes. Additional applications exist for semiconductors and quantum dots. The dissertation research is concerned with a new investigation of the structures and infrared signatures of novel transition-metal carbide clusters using Fourier transform infrared (FTIR) spectroscopy and density functional theory (DFT). FTIR absorption spectra were obtained by trapping the vapor produced by the simultaneous evaporation of transition metal and carbon rods with Nd:YAG lasers in an Ar matrix maintained at ~10 K in a vacuum at ~10<super>-7</super> Torr. Comparison of the vibrational fundamentals and isotopic shifts observed in <super>13</super>C-enriched vibrational spectra to the isotopic spectra predicted by DFT has enabled the identification of vibrational fundamentals of linear NiC₃Ni, cyclic TiC₃, and cyclic ScC₃. The <italic>&nu;</italic>₃(<italic>&sigma;_u</italic>) asymmetric carbon stretching mode of linear NiC₃Ni has been observed at 1950.8 cm<super>-1</super>. Although other small nickel-carbon clusters have been investigated theoretically, this is the first experimental or theoretical study of the structure and infrared signature of NiC₃Ni. Two vibrational fundamentals of cyclic TiC₃ (a fanlike geometry with a transannular metal-carbon bond) were observed at <italic>&nu;</italic>₃(<italic>a</italic>₁)=624.3 and <italic>&nu;</italic>₅(<italic>b</italic>₂)=1484.2 cm<super>-1</super>, corresponding to symmetric metal-carbon and asymmetric carbon-carbon stretching modes, respectively. A third frequency at 573.8 cm<super>-1</super> has provisionally been assigned to the <italic>&nu;</italic>₄(<italic>b</italic>₁) fundamental. Three vibrational fundamentals of cyclic ScC₃ were observed including the <italic>&nu;</italic>₅(<italic>b</italic>₂)=1478.0 cm<super>-1</super> asymmetric carbon stretch, the <italic>&nu;</italic>₃(<italic>a</italic>₁)=557.0 cm<super>-1</super> symmetric metal-carbon stretch, and the <italic>&nu;</italic>₁(<italic>a</italic>₁)=1190.7 cm<super>-1</super> symmetric carbon stretch. The results for TiC₃ and ScC₃ provide the first unambiguous evidence of the cyclic structures suggested by earlier photoelectron spectroscopy studies, significantly improve the accuracy of the <italic>&nu;</italic>₃(<italic>a</italic>₁) measurements, and identify three new vibrational fundamentals. FTIR measured isotopic spectra for all of the fundamentals are in good agreement with the predictions of DFT simulations using the B3LYP hybrid functional. Innovative sample preparation techniques have also been developed in this investigation.

With Texas Christian University's recent acquirement of a tropical research station in Costa Rica, plans for the station's infrastructure as well as research structure are being made. Part of this plan is to make the research station sustainable. Because the research station relies on local streams as a water source, a sustainable water management plan is essential. While such a plan may take years to develop, a foundation for sustainable water use can be made by providing baseline data and suggesting an ongoing stream monitoring program. This project provides a baseline by measuring the (i) chemical, (ii) biological, and (iii) physical properties of two stream sites at the research station. The sites, assessed <italic>a priori</italic> as either pristine or impacted by grazing activity, were then analyzed based on the three parameters. The baseline data of this project also includes maps generated in geographic information systems, which are important in analyzing the regional basin. Based on the type of measurements taken in this project and the foreseen use of the research station, this paper suggests an appropriate stream monitoring program after consideration of three successful monitoring programs.

The Standard Oil of Ohio Company (SOHIO) process refers to the selective oxidation and ammoxidation of propene to produce acrolein and acrylonitrile, used on large scales in industry. The outstanding performance of the SOHIO process has stimulated much fundamental research on its mechanistic details, but four decades after its discovery, the mode of action of the "simple" Bi2O3*MoO3 catalyst remains controversial (Chapter 1). For several years now, we have sought to prepare soluble complexes featuring BiIII(-O)MoVI interactions in pure oxo environments, in order to resemble the proposed SOHIO catalyst active site. During our quest, we have employed calixarene ligands as oxygen rich platforms that can hold the Bi and Mo centers simultaneously. We took advantage of the oxygen-donor lower rim of the calixarenes to prepare a series of BiIII and SbIII metallated complexes that display a broad structural diversity. We synthesized a series of deprotonated calixarenes "calix[n]anions" (including mono- to pentaanionic species) by the reaction of parent calix[n]arenes (n = 5, 7) with alkali metal bases (Chapter 2). The calix[5]arene anions were employed to successfully synthesize for the first time, mono- and bimetallic BiIII and SbIII calix[5]arene complexes containing unreacted OH groups (Chapter 3). In order to expand the number of bismuth and antimony precursors, we decided to explore the reactivity of the calix[n]arenes (n = 6-8) taking advantage of the larger cavity size and conformational exchange. The treatment of parent calix[n]arenes (n = 6-8) with several bismuth and antimony precursors allowed the preparation of a series of metal complexes featuring mono- to tretranuclear structures (Chapter 4). As the chemistry of bismuth and antimony complexes usually has an issue of low solubility, we synthesized mono-silylated calix[5]arenes that upon treatment with bismuth and antimony alkoxides permitted the preparation of highly soluble BiIII and SbIII compounds (Chapter 5). The reactivity of the monometallic BiIII and SbIII calixarene complexes was tested and successfully utilized on the synthesis of the first M/Mo (M = Sb, Bi) heterometallic models supported by calixarene ligands (Chapter 6). Finally, as part of our studies on C-H activation (rate determining step in the SOHIO process) observed in BiIII bisphenolates, we have synthesized the analogous SbIII complexes and discovered that they are able to undergo such bond activations under similar reaction conditions (Chapter 7).

â-Diketiminate ligands of the general formula [R<super>3</super>C{C(R<super>2</super>)N(R<super>1</super>)}₂]<super>-</super> are now among the most ubiquitous chelating systems in all of coordination chemistry. Nacnac (R<super>1</super> = aryl, R<super>2</super> = CH₃, R<super>3</super> = H) has been used to stabilize of a variety of elements in unusually low oxidation states and in the discovery of a variety of novel bonding modes. We were principally interested in investigating the reactivity of nacnac ligands with selenium and tellurium tetrahalides, due to the absence of group 16 centers in the library of nacnac complexes. To this end we synthesized and characterized the first examples of Se- and Te-nacnac complexes, which avoided the usual N,N'-chelation and instead favored reaction at one of the backbone methyl groups via nucleophilic attack by the carbon-carbon double bond of the enamine form of the ligand. Additionally, we have utilized two members of the related ketiminate ligand class, of general formula [R<super>1</super>NC(R<super>2</super>)C(R<super>3</super>)C(R<super>2</super>)O]<super>-</super> to synthesize a variety of metal complexes spanning the periodic table. By comparing and contrasting the coordination preferences of a bulkier, bidentate (R<super>1</super> = aryl) ketiminate ligand to that of a more flexible, tridentate (R<super>1</super> = (CH₂)₂NEt₂) ketiminate ligand, we observed a greater ability of the tridentate ligand to stabilize mono-ligated complexes, as opposed to the bis-ketiminato complexes frequently formed using the bidentate ligand. Furthermore, this investigation has led to a wide range of complex types, including monomers, dimers, tetramers, adducts, and hetero-elemental cages. We have synthesized a series of main group complexes of the commercially available 2,2'-dipyridylamine, an N,N'-chelating ligand not unlike the â-diketiminates. Complexes of this ligand have proven useful in a multitude of applications, in no small part due to the coordinative versatility of this ligand, which can bind in monodentate, bidentate, and tridentate fashions. Finally, we have generated a series of compounds derived from phosphorus ligands based on the bulky trityl (triphenylmethyl = Ph₃C) group. We have found that the considerable steric bulk of trityl diphenylphosphine inhibits coordination to a variety of metal centers, but novel complexes have been formed by employing the HBF₄ salt of Ph₃CPPh₂ as the phosphorus-based ligand.

Hepatitis C, the disease caused by the Hepatitis C Virus (HCV), infects over three million people in the United States alone. In the majority of infected individuals, the virus sets up chronic infection and can ultimately result in liver cancer. The NS5A protein of HCV is thought to provide the virus with means to evade detection by the host immune system and provide resistance to interferon and inhibit apoptosis, or programmed cell death. These mechanisms of apoptotic interference by HCV may be what ultimately lead to hepatocellular carcinoma, the 3rd leading cause of cancer death. This project characterizes the behavior of cell lines that stably expresses NS5A, and their response to apoptotic stimuli. The research aims are to understand how NS5A interferes with apoptosis by identifying what apoptotic proteins it binds to.

Physicists have used billiards to understand and explore both classical and quantum chaos. Recently, in 2001, a group at the University of Texas introduced an experimental set up for modeling the wedge billiard geometry called optical billiard in two dimensions. For the temperature range that was explored, this experiment is more closely related with classical rather than quantum chaos. The motivation for the present work was born from the idea of laying the foundations of a quantum treatment for optical billiards. We call it ``The Escape Problem'', and approach it by applying the concept of a Transparent Boundary Condition (TBC). Since a four-dimensional phase space is computationally very difficult to investigate, here we will explore a pair of one-dimensional examples. First, as a benchmark, we will consider the classical regime by analyzing a "gas of particles'' limited to stay inside a one dimensional box of length L. The focus of our effort is the solution of the corresponding Quantum Initial Value Problem (QIVP). We employ a recently developed numerical method and test it for a simple situation with an exact, analytic solution. The numerical method introduces a novel way to solve a diffusion type equation by implementing discrete transparent boundaries conditions (DTBCs) recently developed by mathematicians. The method is then extended to include a linear, external potential.