No description available.

No description available.

This text describes the synthesis of surface-oriented multilayers based on novel monomeric species. The impetus of this study is to incorporate atypical species and techniques in order to prepare well-ordered assemblies on gold surfaces. These thin films were characterized by one or more of following techniques: grazing angle FT-IR; optical ellipsometry and x-ray photoelectron spectroscopy. First, chemical vapor deposition polymerization was used to prepare surface-oriented monolayers on amine functionalized gold from 4-aminobenzaldehyde and 5-phenyl-1, 3-dioxolane-2, 4-dione. The 4-aminobenzaldehyde showed regular increases in the intensity of characteristic IR absorptions with number of deposition cycles while the dioxolane showed no regularity in this respect. We infer from our data that this technique is a practical way to synthesize highly conjugated polymers. Secondly, we investigated the preparation of surface oriented materials based on host-guest assemblies. Cyclodextrin functionalized gold surfaces could serve as orientational templates for multilayered well-ordered host-guest materials. However, in our study, thiol modified cyclodextrin showed no ability to organize surface multilayers via surface crystallization in the presence of the appropriate host; nor did it show an ability to pre-organize in solution via polyethylene glycol rotaxane formation followed by surface attachment. Finally, surface-oriented organometallic monolayers and multilayers were prepared from alkyne functionalized gold surfaces. Using bis-orthodimethylaminomethyl (NCN) ligands we synthesized two unique surface-oriented organometallic assemblies. Palladium NCN hydrosulfides formed monolayers on gold. Characterization by FT-IR, XPS and ellipsometry show that these species similar to their thiol counterparts. In addition, organometallic polymers were grown from alkyne functionalized surfaces. The thickness of these films, which reached 40 Å by ellipsometry was dependent upon the nature of the alkyne initiator. / text

<p> Monomeric ribosomes and very few subunits are found in mammalian cells and because subunits are required for initiation of protein biosynthesis in both mammalian and bacterial systems, this implies that the dissociation step in the ribosome cycle does not occur spontaneously. Our attention was drawn to the possibility that the monomeric ribosomes in mammalian cells could complex with a dissociation factor. This factor would perhaps be present in the cell in limited supply and would, therefore have to recycle in the course of initiation, from a completed initiation complex to another free ribosome. An assay was set up whereby the existence of a dissociation factor in a subcellular fraction of rat liver could be determined. The perfecting of the assay system for the dissociation factor yielded much information on the ionic concentration necessary for both ribosome and subunit stability. The factor was found to be present in the fraction containing the "native" subunits. This is identical to the situation which exists in E. coli. The factor is capable of dissociating rat liver monomeric ribosomes into 60S and 40S subunits. The factor was found to act on ribosomes freed of both messenger RNA and nascent protein.</p> <p> Purification of the crude dissociation factor preparation was achieved by obtaining at 4°C the 35-65% ammonium sulphate fraction. Purification was also achieved by means of an incubation of the preparation at 40°C for 30 minutes followed by a centrifugation to remove precipitated protein.</p> <p> The DF was determined to have a molecular weight in excess of 85,000 by column chromatography.</p> / Thesis / Master of Science (MSc)

No description available.

Thesis (Ph. D.)--Case Western Reserve University, 2007. / [School of Medicine] Department of Pharmacology. Includes bibliographical references.

Thesis (Ph.D.). / Written for the Dept. of Experimental Surgery. Title from title page of PDF (viewed 2008/01/12). Includes bibliographical references.

Nesta dissertação, apresentamos dois estudos por ressonância paramagnética eletrônica (RPE) de complexos de cobre. O primeiro estudo contempla os complexos mononucleares de cobre e seu objetivo é analisar a simetria de coordenação dos sítios paramagnéticos. Os espectros de RPE obtidos em banda X na temperatura de 50K para as amostras de membranas e bio-membranas dopadas com Cu(ClO4)2 indicam a presença do íon Cu2+ em sítios de simetria axial. Com a análise dos espectros experimentais, obtivemos os parâmetros do Hamiltoniano de spin e através do modelo empírico de Peisach-Blumberg foi possível observarmos que, para a maioria das amostras analisadas, a complexação equatorial do íon Cu2+ ocorre com átomos de nitrogênio e oxigênio. O segundo estudo contempla os complexos dinucleares de cobre e seu objetivo é analisar as interações dipolar e de troca. Os espectros obtidos em banda Q em temperatura ambiente (300K) para o complexo dinuclear [Cu2(Sant)4 (H2O)2] 2.5H2O em sua forma monocristalina indicaram a presença do íon Cu2+ em sítios de simetria axial com duas unidades dinucleares magneticamente não equivalentes por célula unitária na amostra. Com a análise da variação angular das linhas de ressonância foi possível obtermos os parâmetros do Hamiltoniano de Spin e estimarmos a constante de acoplamento de troca como sendo J0 <&asymp;>324 cm1. / This dissertation presents two electron paramagnetic resonance (EPR) studies on copper complexes. The first study focused mononuclear copper complexes and its objective is to analyze the symmetry of coordination of the paramagnetic sites. The 50K X-band EPR spectra obtained for membranes and bio-membranes doped with Cu(ClO4)2 indicates the presence of the Cu2+ ion in axially distorted sites. Through the analysis of the experimental spectra the spin Hamiltonian parameters are obtained and using the Peisach-Blumberg empirical model its possible to notice that the equatorial complexation of the Cu2+ ion occurs with both nitrogen and oxigen for most of the samples. The second study focused dinuclear copper complexes and its objective is to analyze both dipolar and exchange interactions. The room temperature Q-band EPR spectra obtained for the monocrystalline form of the dinuclear complex [Cu2(sant)4 (H2O)2] 2.5H2O indicates the presence of the Cu2+ ion in axially distorted sites with two non-equivalent dimeric units per unit cell of the sample. With the analisys of the angular variation of the resonant lines we are able to obtain the spin Hamiltonian parameters and estimate the exchange coupling constant J0 &asymp; 324 cm1.

Different monomeric diols, with a central rigid FD unit connected with two aliphatic chains of various length, were prepared to react with aromatic mesogenic triad, TOBC. In this manner, thermotropic polyesters with possible low thermal transition temperatures (including Tmand Ti) and high solubility in organic solvent can be generated in view of the non-linear polymeric chain imposed by the rigid, bent FD moieties. In addition to the effect of the aliphatic chain length, polyesters of different molecular weight will be obtained by different synthesis approach (or fractionation of the resulting polyester product) and therefore, the influence of molecular weight on liquid crystalline properties can be evaluated.

Nesta dissertação, apresentamos dois estudos por ressonância paramagnética eletrônica (RPE) de complexos de cobre. O primeiro estudo contempla os complexos mononucleares de cobre e seu objetivo é analisar a simetria de coordenação dos sítios paramagnéticos. Os espectros de RPE obtidos em banda X na temperatura de 50K para as amostras de membranas e bio-membranas dopadas com Cu(ClO4)2 indicam a presença do íon Cu2+ em sítios de simetria axial. Com a análise dos espectros experimentais, obtivemos os parâmetros do Hamiltoniano de spin e através do modelo empírico de Peisach-Blumberg foi possível observarmos que, para a maioria das amostras analisadas, a complexação equatorial do íon Cu2+ ocorre com átomos de nitrogênio e oxigênio. O segundo estudo contempla os complexos dinucleares de cobre e seu objetivo é analisar as interações dipolar e de troca. Os espectros obtidos em banda Q em temperatura ambiente (300K) para o complexo dinuclear [Cu2(Sant)4 (H2O)2] 2.5H2O em sua forma monocristalina indicaram a presença do íon Cu2+ em sítios de simetria axial com duas unidades dinucleares magneticamente não equivalentes por célula unitária na amostra. Com a análise da variação angular das linhas de ressonância foi possível obtermos os parâmetros do Hamiltoniano de Spin e estimarmos a constante de acoplamento de troca como sendo J0 <&asymp;>324 cm1. / This dissertation presents two electron paramagnetic resonance (EPR) studies on copper complexes. The first study focused mononuclear copper complexes and its objective is to analyze the symmetry of coordination of the paramagnetic sites. The 50K X-band EPR spectra obtained for membranes and bio-membranes doped with Cu(ClO4)2 indicates the presence of the Cu2+ ion in axially distorted sites. Through the analysis of the experimental spectra the spin Hamiltonian parameters are obtained and using the Peisach-Blumberg empirical model its possible to notice that the equatorial complexation of the Cu2+ ion occurs with both nitrogen and oxigen for most of the samples. The second study focused dinuclear copper complexes and its objective is to analyze both dipolar and exchange interactions. The room temperature Q-band EPR spectra obtained for the monocrystalline form of the dinuclear complex [Cu2(sant)4 (H2O)2] 2.5H2O indicates the presence of the Cu2+ ion in axially distorted sites with two non-equivalent dimeric units per unit cell of the sample. With the analisys of the angular variation of the resonant lines we are able to obtain the spin Hamiltonian parameters and estimate the exchange coupling constant J0 &asymp; 324 cm1.