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Interactions Of Silver And Gold Complexes With Sulphide Minerals: A Surface Study, Michael John Scaini
Interactions Of Silver And Gold Complexes With Sulphide Minerals: A Surface Study, Michael John Scaini
Digitized Theses
This thesis examines the interactions of the aqueous species {dollar}\rm Ag\sp+,\ AgCl\sb{lcub}x{rcub}\sp{lcub}1-x{rcub},\ AuCl\sb4\sp-{dollar} and AuSH with the surfaces of PbS, (Zn,Fe)S and FeS{dollar}\sb2{dollar} with the aim of better understanding the role that sulphide minerals play in concentrating precious metals from solution. Through the use of surface (XPS, AES, SEM) and conventional (AAS, IC, electrochemistry) analytical techniques, insight into mineral modification, metal chemistry and morphology, alloy composition and solution chemistry is obtained.;Reactions of Ag{dollar}\sp+{dollar} and the three minerals resulted in the presence of Ag{dollar}\sb2{dollar}S and Ag(0) being observed on all mineral surfaces, in a 2 step process where Ag{dollar}\sb2{dollar}S, then Ag(0) …
Astroglial Insulin-Like Growth Factor Binding Proteins: Regulation Of Synthesis And Relationship To Cell Growth, Sheri Lynn Bradshaw
Astroglial Insulin-Like Growth Factor Binding Proteins: Regulation Of Synthesis And Relationship To Cell Growth, Sheri Lynn Bradshaw
Digitized Theses
The insulin-like growth factors (IGFs) regulate the growth and differentiation of a wide variety of tissues, including the brain. The biologic actions of IGFs are modulated by a family of six IGF binding proteins (IGFBPs), which, like IGFs, are synthesized as paracrine factors. We hypothesized that the IGFBPs synthesized by astroglial cells, are regulated by growth factors produced in the developing brain, and modulate the growth of these cells. Primary astroglial cells synthesized IGFBP-2 and IGFBP-3 which were upregulated in a dose dependent manner by IGF-I, IGF-II, and very high concentrations of insulin, suggesting that the growth factors regulate their …
Vuv Laser/Time-Of-Flight Mass Spectroscopy: Valence To Ion-Pair States Transitions Of Brcl And Cl(2), Peng Wang
Vuv Laser/Time-Of-Flight Mass Spectroscopy: Valence To Ion-Pair States Transitions Of Brcl And Cl(2), Peng Wang
Digitized Theses
This thesis describes a newly built vacuum ultraviolet (VUV) laser/time-of-flight (TOF) mass spectrometer system in great detail. The theoretical background behind the techniques is also provided. Tunable, coherent, and monochromatic VUV "laser" radiation was generated by the nonlinear optical technique of two-photon resonantly enhanced four-wave difference-mixing (FWDM) in Kr gas. The Frequency resolution of the recorded spectra is estimated to be {dollar}\leq{dollar}0.2 cm{dollar}\sp{lcub}-1{rcub}.{dollar} The mass resolution, m/{dollar}\Delta{dollar}m, of the linear TOF mass spectrometer {dollar}\geq{dollar}500, which was sufficient to obtain single isotopomer data.;With this instrument, vibrationally and rotationally resolved spectra of the {dollar}E0\sp+{dollar} (v{dollar}\sp\prime=173-203){dollar} ion-pair state {dollar}\leftarrow X0\sp+{dollar} (v{dollar}\sp{lcub}\prime\prime{rcub}=0){dollar} ground state …
Interactions Of Oxygen, Hydrogen And Water With Zr(0001) And Zr(1010), Bing Li
Interactions Of Oxygen, Hydrogen And Water With Zr(0001) And Zr(1010), Bing Li
Digitized Theses
The interaction of oxygen, hydrogen and water with Zr(0001) and Zr(1010) has been studied by surface science techniques. A hopping model of the diffusion of adsorbed species from a surface into the bulk has been formulated and solved mathematically. Applying this model to our AES results on oxygen dissolution, we obtained the Arrhenius expressions for diffusion as: 0.115exp({dollar}-{dollar}44.45 kcal/RT) cm{dollar}\rm\sp2s\sp{lcub}-1{rcub}{dollar} along {dollar}\langle0001\rangle,{dollar} and 1.07exp({dollar}-{dollar}46.18 kcal/RT) cm{dollar}\rm\sp2s\sp{lcub}-1{rcub}{dollar} along {dollar}\langle10\=10\rangle.{dollar};Oxide dissolution was studied by measuring the change of the oxide thickness at a series of temperatures for a constant initial coverage prepared at a fixed and low temperature. The rate-controlling step in …
Spectroscopy Of Unstable Molecules, Hafed Ashur Bascal
Spectroscopy Of Unstable Molecules, Hafed Ashur Bascal
Digitized Theses
The {dollar}\rm B\sp2\Sigma\sp{lcub}+{rcub}{dollar} ion-pair excited states for the unstable group IIB metal monohalide radicals have acquired eminence as the upper levels for the potentially important blue/green lasers. In this work, the metal monohalide radicals were produced by exciting a corona excited electrical discharge in a supersonic gas expansion. The ion-pair-valence {dollar}\rm B\sp2\Sigma\sp{lcub}+{rcub}\gets X\sp2\Sigma\sp{lcub}+{rcub}{dollar} transitions for several of these species were recorded by the method of laser induced fluorescence excitation spectroscopy. For HgCl the resultant spectra recorded over the 368-267nm range reveal an extensive vibrationally and isotopically resolved structure due to transitions between {dollar}\rm X\sp2\Sigma\sp{lcub}+{rcub}\ (2\ge v\sp{lcub}\prime\prime{rcub}\ge0){dollar} and {dollar}\rm B\sp2\Sigma\sp{lcub}+{rcub}\ (75\ge …
1,4-Biradicals In Intermolecular Photocycloaddition Reactions Of Cyclic Enones With Alkenes, And, 1,4-Biradicals In Intramolecular Photocycloaddition Reactions Of Cyclic Enones With Alkenes, David Jack Maradyn
Digitized Theses
The irradiation of cyclic enones with ultraviolet light in the presence of alkenes results in the formation of cyclobutane adducts possessing head-to-head and/or head-to-tail regiochemistry. The long-accepted Corey-de Mayo mechanism predicts that the regiochemistry of the cyclobutane adducts is controlled by the relative orientation of the enone and alkene in an exciplex intermediate. Weedon and co-workers have demonstrated that partitioning of 1,4-biradical intermediates between starting material and cyclobutane products controls the product regiochemistry in the intermolecular photocycloaddition reactions of 2-cyclopentenones with alkenes.;These earlier results have been extended. The 1,4-biradical intermediates formed in the photocycloaddition reactions of 2-cyclohexenone with alkenes, in …
Application Of Expert Systems In Analytical And Environmental Chemistry, Qiwei Zhu
Application Of Expert Systems In Analytical And Environmental Chemistry, Qiwei Zhu
Digitized Theses
Expert systems are knowledge based computer programs that offer the possibility of combining theories with heuristic expertise, and are therefore capable of solving domain-specific problems. However, little is known about how human knowledge can be effectively and precisely transferred into computer programs. In addition, the lack of a seamless man-machine interface also causes reduced general acceptance of expert systems. In this thesis, the process of knowledge acquisition and the role of the user interface in expert systems are investigated. Results are presented that describe the development of two prototypic expert systems: SPILLexpert and GSMSdiagnosis.;The knowledge domain matrix (KDM) is an …
Core Level Spectroscopy Studies Of Organosilicon Compounds, Jianzhang Xiong
Core Level Spectroscopy Studies Of Organosilicon Compounds, Jianzhang Xiong
Digitized Theses
Si core level X-ray Absorption Fine Structures (XAFS) spectroscopy has been used to study, in the gas phase, the structure and bonding of a series of highly symmetric organosilicon compounds, Si(CH{dollar}\sb3)\sb4{dollar} (TMS), Si{dollar}\rm\sb2(CH\sb3)\sb6{dollar} (HMDS), Ge (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} (GESI4), Si (Ge(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} (SIGE4), and Si (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} (SISI4), which can be used as model compounds for silicon-germanium electronic materials.;The Si K- and L{dollar}\sb{lcub}2,3{rcub}{dollar}-edge X-ray absorption near edge structure (XANES) of HMDS, GESI4 SIGE4 and SISI4 have been recorded with synchrotron radiation and calculated by the multiple-scattering (MS) X{dollar}\alpha{dollar} method. It is found that there is a significant difference in the absorption coefficient in the …
Diagnostic Expert Systems In Instrumental Analysis, Hai Du
Diagnostic Expert Systems In Instrumental Analysis, Hai Du
Digitized Theses
The acquisition of knowledge is a key phase in the implementation of expert systems yet represents a significant bottleneck. An explanation-based method was applied to knowledge compilation in a GC diagnostic system. A package of macros for Microsoft Excel, MATRIX, was then developed to enable domain experts to build rule-based knowledge bases for expert systems. The MATRIX macros can be used as domain-oriented knowledge acquisition tools that are specialized in coding knowledge concerning the diagnosis of faults in analytical instruments. These knowledge acquisition tools do not require formulation of any certainty factors to resolve conflicts and enable experts in analytical …
Aspects Of Reactions Of Sulfonyl Compounds With Nucleophiles, Manjinder Singh Gill
Aspects Of Reactions Of Sulfonyl Compounds With Nucleophiles, Manjinder Singh Gill
Digitized Theses
This thesis describes four topics in organic sulfur chemistry involving reactions of sulfonyl compounds with nucleophiles. In the first chapter the reactions of aromatic sulfonyl chlorides with amines in aqueous media were studied. The observed pH-yield profiles pointed strongly to the involvement at high pH of third-order processes leading to the sulfonamides. A new term {dollar}(k\sb{lcub}\rm NOH{rcub}){dollar} was introduced in the rate expression (eq 9) and the calculated pH-yield profiles from eq 10 gave a good agreement with experimental data. The increased value of rate constants with alkyl chain size of the amine, suggested aggregation of reactants due to hydrophobic …
Multicomponent Interdiffusion In Micellar Solutions And Microemulsions, Ling Hao
Multicomponent Interdiffusion In Micellar Solutions And Microemulsions, Ling Hao
Digitized Theses
This thesis focuses on multicomponent interdiffusion in micellar solutions and microemulsions. The Taylor dispersion technique is used to measure ternary diffusion coefficients for aqueous micellar solutions of: sodium dodecylsulfate (SDS)/NaCl; SDS/alcohol solubilizates; and sodium cholate (SC)/alcohol solubilizates. Ternary diffusion coefficients are also reported for water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-heptane and water/2-propanol/n-hexane water-in-oil microemulsions. The results include cross-diffusion coefficients, which provide new insights into the interactions between diffusing surfactants and solubilizates.;The diffusion coefficient of SDS in aqueous salt solutions determined by Taylor dispersion is found to be smaller than the diffusion coefficient of the micelles indicated by the popular quasi-elastic light scattering …
Variable Energy Photoelectron Spectra Of Metal Carbonyls, Yongfeng Hu
Variable Energy Photoelectron Spectra Of Metal Carbonyls, Yongfeng Hu
Digitized Theses
High resolution gas phase photoelectron spectra of transition metal carbonyls, W(CO){dollar}\sb6,{dollar} Os(CO){dollar}\sb4{dollar}L (L = CO, PMe{dollar}\sb3),{dollar} CpM(CO){dollar}\sb3{dollar} (M = Mn, Re), CpFe(CO){dollar}\sb2{dollar}I, and Re(CO){dollar}\sb5{dollar}X (X = Re(CO){dollar}\sb5,{dollar} Cl, Br, and I) are reported. The advantages of monochromatized synchrotron radiation for studying the electronic structure of organometallic molecules are demonstrated. All the levels of these metal carbonyls from valence to inner-valence and core levels at high resolution can be studied in one spectrum.;For the core levels, vibrational fine structure is clearly resolved for the first time on the core of W 4f levels of W(CO){dollar}\sb6,{dollar} and this structure can be rationalized …
Ftir Spectroscopic Studies Of Adsorbates On Metal Surfaces, Rita Violet Kasza
Ftir Spectroscopic Studies Of Adsorbates On Metal Surfaces, Rita Violet Kasza
Digitized Theses
Fourier transform infrared (FTIR) spectroscopic studies of adsorbates on metal surfaces have been carried out using FTIR reflection-absorption spectroscopy, synchotron radiation FTIR and time-resolved FTIR, along with Auger electron spectroscopy, low energy electron diffraction, thermal desorption spectroscopy, nuclear reaction analysis and work function change. For water on hex and (1 x 1) Pt(100), clustering takes place readily at low temperature from the lowest coverages, and a small number of large clusters tend to form. On Pt(100) containing Si impurity, clusters are initially nucleated at impurity sites and tend to be smaller and more numerous. For H{dollar}\sb2{dollar}O/Al(100) at T {dollar}<{dollar} 130 K, a distribution of relatively small clusters exists. At coverages under 0.35 ML on Ni(110), water adsorbs monomerically at 85-180 K, and the H{dollar}\sb2{dollar}O wagging and rocking modes can be observed in the far IR.;On both stepped Ni(760) and Ni(110), the saturation coverage for the first chemisorbed layer is 0.5 ML (ML = {dollar}1.15\times10\sp{lcub}15{rcub}{dollar} molecules cm{dollar}\sp{lcub}-2{rcub}){dollar} and no FTIR activity (1000-4000 cm{dollar}\sp{lcub}-1{rcub}){dollar} is observed until the coverage exceeds 0.5 ML. Less water exists in the A{dollar}\sb1{dollar} desorption state on Ni(760) compared with D{dollar}\sb2{dollar}O/Ni(110). At temperatures above 398 K, water is observed to autocatalytically dissociate on clean Ni(760), forming H{dollar}\sb2{dollar}(g) and O(ads). Ni(760) appears to be much more reactive than Ni(110), resulting in a significantly higher reaction probability. A (2 x 1)-O phase is formed upon completion of the reaction, corresponding to an absolute oxygen coverage of 0.3-0.4 ML depending on the reaction temperature.;A fast time-resolved Fourier transform spectroscopy (FTRFTS) system has been developed for obtaining reflection IR data on surfaces with microsecond time resolution. Laser induced thermal desorption is a suitable method for modulating the CO coverage on a Pt surface. Conversion of linearly bonded to bridge bonded CO can be observed in thermal transients, suggesting that the species are not in equilibrium at room temperature. The FTRFTS system has been used for the first time to obtain FTIR-RAS spectra of CO on Pt(111).
Variable Energy Photoelectron Spectra Of Organometallic Compounds Of The Late Transition Metals, Xiaorong Li
Variable Energy Photoelectron Spectra Of Organometallic Compounds Of The Late Transition Metals, Xiaorong Li
Digitized Theses
This thesis describes photoelectron spectroscopy (PES) studies with variable photon energy for organometallic molecules of late transition metals, including cobalt, rhodium, iridium, nickel, palladium, platinum, copper, and silver. Synchrotron radiation (in the range of 30 to 170 eV photon energy) and traditional helium I (21.22 eV) and helium II (40.81 eV) light sources were used in this study, with the aid of theoretical ground state and cross section calculations by using X{dollar}\alpha{dollar}-SW and Gelius model methods. With these techniques the variation of band intensities as a function of photon energy were investigated. The very different intensity features between metal d …
The Growth And Magnetic Properties Of Metal Overlayer Systems: Palladium/Copper(100), Iron/Aluminum(100) And Iron/Sulfur/Gallium Arsenide(100), Geoffrey William Anderson
The Growth And Magnetic Properties Of Metal Overlayer Systems: Palladium/Copper(100), Iron/Aluminum(100) And Iron/Sulfur/Gallium Arsenide(100), Geoffrey William Anderson
Digitized Theses
Epitaxial growth of a metal overlayer on an appropriate substrate can be utilized to create systems which exhibit unique chemical and magnetic properties. This thesis will outline the investigation of three metal overlayer systems: Pd/Cu(100), Fe/Al(100) and Fe/S/GaAs(100). In the Pd/Cu(100) system the growth and evolution of defects were examined using re-emitted positron spectroscopy. Two changes in growth mode were observed: at 0.5 monolayer (representing the completion of the first alloy layer) and 1 monolayer Pd coverages (representing the start of bulk Pd growth). The bulk Pd film was observed to contain 1% vacancy-type defects. In the Fe/Al(100) system the …
Electronic Structure Of Gold-Silver Bimetallics, Arthur Bzowski
Electronic Structure Of Gold-Silver Bimetallics, Arthur Bzowski
Digitized Theses
The main thrust of this thesis concerns studies of the electronic structure of Au-Ag bimetallic materials, both in bulk alloys and in metallic overlayers on Ru(001). First, a series of bulk Au-Ag alloys: Au{dollar}\rm\sb{lcub}0.75{rcub}Ag\sb{lcub}0.25{rcub},\ Au\sb{lcub}0.67{rcub}Ag\sb{lcub}0.33{rcub},\ Au\sb{lcub}0.50{rcub}Ag\sb{lcub}0.50{rcub},\ Au\sb{lcub}0.25{rcub}Ag\sb{lcub}0.95{rcub},\ and\ Au\sb{lcub}0.05{rcub}Ag\sb{lcub}0.95{rcub}{dollar} has been studied using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and X-ray absorption near-edge structure (XANES). It is found that in alloys with {dollar}>{dollar}50% atomic Au, the alloy d-band width narrows little relative to that of pure Au; however at 50% (and less) atomic Au concentration, the widths of the Au-Ag alloy d-band are much smaller than that …
New Porphyrins As Semiconductor Photosensitizers: Molecular Engineering For Solar Energy Conversion, Biswajit Choudhury
New Porphyrins As Semiconductor Photosensitizers: Molecular Engineering For Solar Energy Conversion, Biswajit Choudhury
Digitized Theses
The organizing properties of surface-active porphyrins can be employed to obtain large area, ordered arrays of electroactive organic molecules. The design, synthesis, and characterization of two families of surface active porphyrins, possessing variety of side chains, is described. These materials are solid at room temperature and exhibit well-behaved monomolecular films at an air-water interface.;In compressed monolayers, the porphyrin ring appears to be oriented so that the plane of the ring is perpendicular to the surface. The surface pressure-molecular area isotherms change with the length and nature of the side chains in a manner which suggests that a long side chain …
Part I 2+2 Photocycloaddition Reactions Of N-Acylindoles With Alkenes Part Ii Photochemical Reactions In Supercritical Carbon Dioxide, Islet Brian Des
Part I 2+2 Photocycloaddition Reactions Of N-Acylindoles With Alkenes Part Ii Photochemical Reactions In Supercritical Carbon Dioxide, Islet Brian Des
Digitized Theses
Part I. Irradiation of 2-methyl, 3-methyl and 2,3-dimethyl substituted N-acylindoles in the presence of alkenes results in the formation of {dollar}\lbrack{dollar}2+2{dollar}\rbrack{dollar} cycloadducts which contain cyclobutane rings. The regiochemistry of the major product in all cases examined was found to be the result of initial bond formation from the 2-position of the N-acylindole to the less substituted terminus of the alkene. The quantum yield of cycloadduct formation was determined for the photocycloaddition reaction of the N-benzoyl derivatives with methyl acrylate and for the N-carboethoxy derivatives with 2-methylpropene. The reaction efficiency was found to be dependent on two factors. The first of …
Marcus Theory Applied To Acetal Cleavage And Aldol Reactions, Jonathan Arthur Barker
Marcus Theory Applied To Acetal Cleavage And Aldol Reactions, Jonathan Arthur Barker
Digitized Theses
The acid catalyzed and uncatalyzed hydrolysis of the acetal 2,2-dimethoxypropane (DMOP) and the ortho ester trimethylorthoacetate (TMOA) have been studied in aqueous solution at 25{dollar}\sp\circ{dollar}C. Theoretical and experimental evidence have been found for a base catalyzed E2 mechanism of DMOP hydrolysis proceeding through an enol ether. This mechanism is neither predicted nor observed for TMOA hydrolysis. The specific acid catalyzed and uncatalyzed rate constants for hydrolysis are for DMOP k{dollar}\rm\sb{lcub}H+{rcub}=(2.5\pm0.3)\times10\sp3\ M\sp{lcub}-1{rcub}s\sp{lcub}-1{rcub},\ k\sb w=(3.6\pm0.2)\times10\sp{lcub}-8{rcub}\ s\sp{lcub}-1{rcub},\ k\sb{lcub}OH-,E2{rcub}=(2.8\pm0.4)\times10\sp{lcub}-8{rcub}\ M\sp{lcub}-1{rcub}s\sp{lcub}-1{rcub},\ and\ for\ TMOA\ k\sb{lcub}H+{rcub}=(2.05\pm0.12)\times10\sp4\ M\sp{lcub}-1{rcub}s\sp{lcub}-1{rcub},\ k\sb w=(3.7\pm0.3)\times10\sp{lcub}-6{rcub}\ s\sp{lcub}-1{rcub}.{dollar} General acid catalysis was observed for TMOA with four general acids. From the Bronsted plot, {dollar}\alpha=0.76\pm0.05.{dollar} …
Homo- And Hetero-Nuclear Clusters Of Platinum And Rhenium, Leijun Hao
Homo- And Hetero-Nuclear Clusters Of Platinum And Rhenium, Leijun Hao
Digitized Theses
ABSTRACT HAS BEEN ARCHIVED 07/22/97;
Intermolecular Forces And Statistical Mechanics Of Liquids, Maria Koulis
Intermolecular Forces And Statistical Mechanics Of Liquids, Maria Koulis
Digitized Theses
This research is involved with the construction of potential energy models for the interaction of closed shell atoms and/or molecules and with the study of the thermodynamic properties of pure liquids and liquid mixtures, through the use of statistical mechanical perturbation theory.;The previously developed Exchange-Coulomb potential energy model for the interaction of closed shell atoms is modified to correct its unphysical behaviour for small interspecies distances and so that it is applicable for interactions involving molecules. The new potential energy model is based on using the Heitler-London energy to represent the repulsive part, and a damped and overall corrected dispersion …
Reactions Of Group 14-Halide Bonds With Dimethylplatinum(Ii) Complexes, Christopher James Levy
Reactions Of Group 14-Halide Bonds With Dimethylplatinum(Ii) Complexes, Christopher James Levy
Digitized Theses
The oxidative addition of E-X bonds (E = Si, Ge, Sn; X = halide) to {dollar}\lbrack\rm PtMe\sb2(diimine)\rbrack{dollar} yields a number of new Pt(IV) complexes containing Pt-E linkages. The complexes {dollar}\lbrack\rm PtXMe\sb2(Me\sb3Si)(diimine)\rbrack{dollar} (X = Br, I) are the first well-characterized examples of Pt(IV)-silyl species. The X-ray structure of {dollar}\lbrack\rm PtIMe\sb2(Me\sb3Si)(bipy)\rbrack{dollar} shows the longest single Pt-I bond reported, and demonstrates the very strong trans influence of the {dollar}\rm Me\sb3Si{dollar} ligand. The X-ray structure of {dollar}\lbrack\rm PtIMe\sb2(Me\sb3Sn)(bipy{dollar}-{dollar}\sp{lcub}t{rcub}\rm bu\sb2)\rbrack{lcub}\cdot{rcub}0.5Me\sb3SnI{lcub}\cdot{rcub}CH\sb2Cl\sb2{dollar} reveals a five coordinate {dollar}\rm Me\sb3SnI{dollar} unit with a novel {dollar}\rm I\cdot\cdot\cdot Sn{dollar}-I interaction.;Many of the Pt-Sn systems studied involve the rapid reversible oxidative addition …
Circular Dichroism And Luminescence Studies Of Copper Binding To Metallothionein, Paul Anthony Presta
Circular Dichroism And Luminescence Studies Of Copper Binding To Metallothionein, Paul Anthony Presta
Digitized Theses
The metallothioneins (MT) are a class of low molecular weight, cysteine rich proteins found in almost all living things. The high sulfhydryl content imparts to these proteins the unique ability to bind a wide range of metals. The metallothioneins have been implicated in the storage and transport of essential metals, such as zinc and copper, and in the detoxification of toxic metals, such as cadmium. However, the exact physiological functions of these proteins remain a matter of speculation. In particular, little is known about the interactions of copper with MT. In this thesis, the structural and mechanistic properties of copper …
On The Palmitoylation Of Surfactant-Associated Protein C, Riad Qanbar
On The Palmitoylation Of Surfactant-Associated Protein C, Riad Qanbar
Digitized Theses
Surfactant-associated protein C (SP-C) contributes to the surface active properties of pulmonary surfactant. Processed from a 21 kDa precursor, the mature form of SP-C is 34-35 amino acids in length. Both the precursor and the mature protein are modified by palmitoylation. Due to its small size and extreme hydrophobicity, SP-C has been difficult to isolate, detect and study. Using molecular exclusion chromatography, SP-C was isolated from calf lung surfactant extract, characterized by partial sequencing, amino acid analysis, tricine polyacrylamide gel electrophoresis, and absence of immune-reactivity with antibodies raised against surfactant-associated protein B (SP-B). A method was developed to label, detect …
A New Photocatalytic Reactor For The Photodegradation Of Organic Contaminants In Water, Julio E. Valladares
A New Photocatalytic Reactor For The Photodegradation Of Organic Contaminants In Water, Julio E. Valladares
Digitized Theses
The {dollar}\rm TiO\sb2{dollar} photocatalytic degradation and mineralization of organic pollutants in water has been broadly demonstrated at the laboratory level for a wide number of organic pollutants. However, there are still some problems that need to be addressed in order to make this technology more practical. The design of heterogeneous photocatalytic reactor systems, still in the infancy of their development, is facing different problems such as light scattering, oxygen starving, particle separation and mass transfer. Additionally, there have also been a lack of a general method to evaluate the performance of the different reactor systems.;The present work addresses these problems …
Spectroscopic Properties Of Copper Binding To The Protein Metallothionein, Anna Rae Green
Spectroscopic Properties Of Copper Binding To The Protein Metallothionein, Anna Rae Green
Digitized Theses
Metallothionein (MT) is a low molecular weight protein found in the kidneys and livers of all mammals. Twenty of its 61 or 62 amino acid residues are cysteinyl residues, allowing the protein to act as an impressive chelating agent. Although it has been well established that mammalian MT binds seven M(II) (M = Cd(II), Zn(II), Hg(II)) ions tetrahedrally in two metal-thiolate clusters of the form M{dollar}\sb4{dollar}(S{dollar}\rm\sb{lcub}cys{rcub})\sb{lcub}11{rcub},{dollar} (the {dollar}\alpha{dollar} domain) and {dollar}\rm M\sb3(S\sb{lcub}cys{rcub})\sb9,{dollar} (the {dollar}\beta{dollar} domain), little is known about the structure of copper-containing metallothioneins. In this thesis, absorption, circular dichroism (CD) and emission spectroscopies and excited state lifetime data are …
Structural Studies On Silver(I) Metallothionein, Ziqi Gui
Structural Studies On Silver(I) Metallothionein, Ziqi Gui
Digitized Theses
Metallothioneins (MT) are a class of low molecular weight, cysteine rich proteins in almost all living things. These proteins have been found to bind a wide range of metals both in vivo and in vitro due to the unusually high cysteinyl sulfur content. The metallothioneins are believed to possess the ability to store and transport essential metals, such as Zn(II) and Cu(I), and also to detoxify toxic metals, such as Cd(II) and Hg(II). However, the precise physiological functions of these proteins still remain unclear to date. As silver(I)-metallothioneins have shown different stoichiometric ratios of Ag:MT from Zn(II)- and Cd(II)-metallothioneins in …
High Resolution And Wideline Nmr Studies Of Membrane Associated Molecules Involved In Signal Transduction, Alan Cavell Rigy
High Resolution And Wideline Nmr Studies Of Membrane Associated Molecules Involved In Signal Transduction, Alan Cavell Rigy
Digitized Theses
The primary focus of our investigations were centered around understanding the biochemical basis of the early events involved in signal transduction. Our work has involved two novel systems: (1) sphingolipid metabolites and (2) a synthetic peptide representing the transmembrane region of the human epidermal growth factor receptor (hEGFR).;Sphingolipid metabolites have emerged as physical modulators of many signalling pathways, including cell growth regulation, and signal transduction. N,N-({dollar}\sp2{dollar}H{dollar}\sb6{dollar}) -dimethylsphingosine and ({dollar}\sp2{dollar}H{dollar}\sb4{dollar}) -lysogalactosyl ceramide were produced by partial synthesis and studied via wideline {dollar}\sp2{dollar}H NMR, as a function of pH. Spectra of ({dollar}\sp2{dollar}H{dollar}\sb6{dollar}) -dimethylsphingosine identified that the molecule's orientation and behaviour are largely …
Intramolecular Aldol Condensation Reactions And Transacetalization Equilibria, Junan Guo
Intramolecular Aldol Condensation Reactions And Transacetalization Equilibria, Junan Guo
Digitized Theses
Part I. Intramolecular aldol condensation reactions. The detailed kinetics and equilibrium for the intramolecular aldol condensation reaction of 2,5-hexanedione, 2, 6-heptanedione, 1-phenyl-1, 5-hexanedione and 5-oxohexanal were studied and correlated in terms of Marcus theory. All the reactions, with the readily explained exception of the intramolecular aldol addition of 5-oxohexanal, gave us approximately constant intrinsic barriers: 14.49 {dollar}\pm{dollar} 0.82 kcal/mol for the intramolecular aldol addition step and 13.99 {dollar}\pm{dollar} 0.74 kcal/mol for the subsequent dehydration step, which are also in excellent agreement with the intrinsic barriers found for intermolecular aldol condensation reactions.{dollar}\sp{lcub}16{rcub}{dollar} This means that Marcus theory is applicable to intramolecular …
Rate And Equilibrium Constants Of Useful Reactions, Jinqiao Lu
Rate And Equilibrium Constants Of Useful Reactions, Jinqiao Lu
Digitized Theses
Part I. The halogenation of propiophenone has been reported to give rise to benzoic acid and acetic acid. It was discovered that under some conditions, the major product of the chlorination of propiophenone is 2-phenylglyceric acid, and that this appears to be a general reaction. 1-Phenyl-1,2-propanedione and 3-chloro-1-phenyl-1,2-propanedione have been proven to be the key intermediates on the chlorination path leading to 2-phenylglyceric acid. The migratory aptitudes of substituted methides ({dollar}\sp-{dollar}CH{dollar}\sb2{dollar}X) are also reported.;Part II. For the classical Michael reaction, the forward addition rate is second order overall, first order in the concentration of methyl cinnamate and first order in …