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Full-Text Articles in Medicinal-Pharmaceutical Chemistry

Preparation Of Functionalized Polymers Utilizng A Soluble Highly Reactive Form Of Calcium, Reuben D. Rieke Jan 1993

Preparation Of Functionalized Polymers Utilizng A Soluble Highly Reactive Form Of Calcium, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Calcium-substituted polymeric reagents are provided. These reagents can be prepared via the oxidative addition of a soluble highly reactive calcium species to organic and inorganic polymers containing alkyl, aryl, or alkylaryl pendent groups substituted with halide atoms, cyanide molecules, 1,3-dienes, or any conjugated poly unsaturated system. Preferably, the polymer is a cross linked p-bromopolystyrene, p-chloropolystyrene, p fluoropolystyrene, or chloromethylated polystyrene. Preferably, the soluble highly reactive calcium species is prepared from the reduction of Ca(II) salts with an alkali metal arene, such as lithium biphenylide. These calcium-substituted polymeric reagents react with a variety of electrophiles to yield functionalized polymers. Reaction with …

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Telomere Processing In Euplotes, Joris Robert Vermeesch, Dewight Williams, Carolyn M. Price Jan 1993

Telomere Processing In Euplotes, Joris Robert Vermeesch, Dewight Williams, Carolyn M. Price

Department of Chemistry: Faculty Publications

In Euplotes crassus millions of telomeres are synthesized during the sexual phase of the life cycle. Since these newly synthesized telomeres are longer than normal macronuclear telomeres, they must be trimmed to the mature size. We have examined the timing and mechanism of this trimming step. We have shown that a sudden decrease in telomere length takes place at a specific time during macronuclear development. The decrease in telomere length is not caused by incomplete replication of the most terminal DNA sequences; rather it is the result of an active processing event that occurs independently of DNA replication. The developmentally …

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Preparation Of Functionalized Polymers Utilizing A Soluble Highly Reactive Form Of Calcium, Reuben D. Rieke Jan 1993

Preparation Of Functionalized Polymers Utilizing A Soluble Highly Reactive Form Of Calcium, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Calcium-substituted polymeric reagents are provided. These reagents can be prepared via the oxidative addition of a soluble highly reactive calcium species to organic and inorganic polymers containing alkyl, aryl, or alkylaryl pendent groups substituted with halide atoms, cyanide molecules, 1,3-dienes, or any conjugated poly unsaturated system. Preferably, the polymer is a cross linked p-bromopolystyrene, p-chloropolystyrene, p-fluoropolystyrene, or chloromethylated polystyrene. Preferably, the soluble highly reactive calcium species is prepared from the reduction of Ca(II) salts with an alkali metal arene, such as lithium biphenylide. These calcium-substituted polymeric reagents react with a variety of electrophiles to yield functionalized polymers. Reaction with Cu(I) …

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Telomere Structure In Euplotes Crassus: Characterization Of Dna-Protein Interactions And Isolation Of A Telomere-Binding Protein, Carolyn M. Price Jan 1990

Telomere Structure In Euplotes Crassus: Characterization Of Dna-Protein Interactions And Isolation Of A Telomere-Binding Protein, Carolyn M. Price

Department of Chemistry: Faculty Publications

The nucleoprotein structure of telomeres from Euplotes crassus was studied by using nuclease and chemical footprinting. The macronuclear telomeres were found to exist as DNA-protein complexes that are resistant to micrococcal nuclease digestion. Each complex encompassed 85 to 130 base pairs of macronuclear DNA and appeared to consist of two structural domains that are characterized by dissimilar DNA-protein interactions. Dimethyl sulfate footprinting demonstrated that very sequence-specific and salt-stable interactions occur in the most terminal region of each complex. DNase I footprinting indicated that DNA in the region 30 to 120 base-pairs from the 5' end lies on a protein surface; …

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Gas Phase Hydrogen Permeation In Alpha Titanium And Carbon Steels, Donald L. Johnson, Kiritkumar K. Shah, Bruce H. Reeves, Vijay L. Gadgeel Jan 1980

Gas Phase Hydrogen Permeation In Alpha Titanium And Carbon Steels, Donald L. Johnson, Kiritkumar K. Shah, Bruce H. Reeves, Vijay L. Gadgeel

Department of Chemistry: Faculty Publications

Commercially pure titanium rods were machined into hollow cylinders and gas-phase permeation and diffusion measurements obtained with a quadrupole residual gas analyzer at temperatures between 400-800°C and pressures between 0.533 and 266.6 Nrn-2. Pressure dependence measurements established that phase boundary reactions as well as lattice diffusion control the transport process. Lag-time data yield excellent agreement with the diffusivity data of Wasilewski and Kehl and Papazoglou and Hepworth for the case where phase boundary reactions are taken into account. The best value of the diffusivity is D = 2.1 x 10-2 exp (-50,40O/RT). Analysis of lag-time data reveals …

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