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Calcium Metabolismn In Volvox Carteri, Bridget Anne Neville

Honors Theses

Calcium metabolism is involved in many ways in the cellular activities of the colonial green alga, Volvox carteri. Various drugs that are known in other systems to cause specific changes in calcium metabolism, gave rise to various visible metabolic effects in this study. These effects provide evidence for calcium's role in Volvox growth and development and in its cytoskeleton. Another way that calcium exerts its effect on Volvox is by acting as a second messenger in a G-protein/inositol phosphate signal transduction pathway.

This study also supports the fact that cytoskeletal components are important for development in Volvox. Both microtubules and …

Suspended Particulate Matter And Sediment Of Penobscot Estuary, Craig M. Pochini

Honors Theses

An automated scanning electron microscope with an energy dispersive spectrometer was used to gather morphological and chemical information on individual particles from the suspended particulate matter of the Penobscot Estuary and the sediment of Goose Cove/Pond. The goals of the Penobscot Estuary study were to investigate the transport of particles into and through an estuary, the speciation of elements, the abundance of heavy metals, and the background levels of heavy metals. The majority of particles were aluminosilicates originating from a riverine source. Heavy metals were not abundant in the Penobscot Estuary. The objectives of the Goose Cove/Pond study were to …

Microwave Plasma Chemical Vapor Deposited Diamond Tips For Scanning Tunneling Microscopy, Sacharia Albin, Jianli Zheng, John B. Cooper, Weihai Fu, Arnel C. Lavarias

Electrical & Computer Engineering Faculty Publications

Diamond microparticles were grown on etched tungsten wires using a microwave plasma-assisted chemical vapor deposition process. The apexes on cubo-octahedral particles bound by {100} and {111} facets were effectively used as tunneling tips for scanning tunneling microscopy. The atomically resolved surface image of highly oriented pyrolytic graphite was acquired. Tunneling characteristics revealed a higher electron emission from the diamond tips than that from the platinum–iridium tips. The same diamond tips were used to produce surface indentation and its image. © 1997 American Institute of Physics.

A Niobium(V) Complex With Mixed O,S-Donor Ligands. Synthesis, Structure And Properties Of The Anion Tris(2-Mercapto-4-Methylphenolato)Niobate(V), Paul Challen, Diane Peapus, Karen Magnes

Paul R. Challen

Reaction of Nb(OEt)5 with 2-mercapto-4-methylphenol (mmpH2) in the presence of triethylamine gave the mononuclear tris complex (Et3NH)[Nb(mmp)3] which was structurally characterized. The coordination geometry around the niobium is between octahedral and trigonal prismatic, with a twist angle of 41.5°. The mercaptophenolate ligands are arranged around the metal in a “propeller” fashion. (Et3NH)[Nb(mmp)3] was characterized by IR, 1H NMR and UV-vis spectroscopies, and cyclic voltammetry. A reversible reduction wave found at −1.03 V is for reduction to the NbIV complex.

Voltammetric Studies Of Mn@C82, Mark Anderson, Harry Dorn, Paul Burbank, James Gibson

Mark R. Anderson

The voltammetry for a series of related endohedral metallofullerenes is reported. It is found that as additional metal atoms are inserted into the fullerene cage, the first reduction of the metallofullerenes shifts to more negative potentials. This is consistent with more charge being transferred to the fullerene cage from the additional metal atom; however, the magnitude of the shift is much smaller than expected.

Direct Measurement Of Diffuse Double-Layer Forces At The Semiconductor/Electrolyte Interface Using An Atomic Force Microscope, Kai Hu, Fu-Ren F. Fan, Allen J. Bard, Andrew C. Hillier

Andrew C. Hillier

The forces between a silica probe and an n-type TiO2 single-crystal electrode were measured using an atomic force microscope in an aqueous electrolyte solution. These interactions were a strong function of the solution pH, the presence of specifically adsorbed anions, and the TiO2 electrode potential. For a series of pH values, a strong electrostatic repulsion was seen at high pH and decreased as the pH was reduced. At pH values below 5.5, the interaction became attractive. A series of force measurements between SiO2 and n-type TiO2 showed a repulsive interaction when TiO2 was held at negative electrode potentials, which transformed …