Chemistry Commons^™

Electrocrystallization Of Strongly Adherent Brushite Coatings On Prosthetic Alloys (Continuation), Jody G. Redepenning

Department of Chemistry: Faculty Publications

An electrolytic method for providing bone-emulating, phosphate coatings on prosthetic appliances. Such coatings serve to enhance bone furation after implantation of the appliances. The method of the invention is an electrolysis process wherein the appliance to be coated is immersed in a phosphate-containing electrolyte to serve as the cathode of the electrolysis process. When current is appIied to the electrolysis cell, the electrolyte solution, which includes calcium ions and dihydrogen phosphate ions, is caused to rapidly increase in (localized) pH proximate the cathode element. The localized pH increase creates a supersaturated local condition causing less soluble calcium phosphate salts to …

Studies Directed Toward Enantioselective Catalysis, Brian E. Jones

Open Access Master's Theses (through 2010)

Many organic molecules of modest size and complexity have chirality.That is, these molecules can exist in more than one stereoisomeric form.There is a strong desire to synthesize chiral compounds that exist in the form of a single stereoisomer.The method of synthesizing chiral compounds that was studied in our research employed a less than stoichiometric amount of chiral catalyst to both catalyze and control the stereochemical outcome of the reactions attempted.

A new chiral ligand was developed to be used as part of the chiral catalyst.This new ligand was used in the enantioselective Diels-Alder cycloaddition reaction and the enantioselective allylation reaction …

Primase Structure And Function, Mark A. Griep

Department of Chemistry: Faculty Publications

Primase is the ssDNA-dependent RNA polymerase that synthesizes RNA primers during DNA replication. In common with all DNA and RNA polymerases, primase has structural and functional features involved in polymer elongation. As RNA polymerase, it has structural and functional features for initiating chain synthesis. As a primase, it has structural and functional features for initiating chain synthesis on ssDNA. Using amino acid sequence analysis the structure of Escherichia coli primase responsible for binding zinc, at least three magnesium, and DnaB helicase has been identified. One of the magnesium binding motifs resembles the “active magnesium” motif found in all DNA and …

A Nanosecond Ord Study Of Hemoglobin, Lawrence J. Parkhurst

Lawrence Parkhurst Publications

This year marks the one hundredth anniversary of the first observation of CO photodissociation from HbCO, with the correct interpretation and publication following in the next year (Haldane and Smith, 1896). Little of kinetic importance could be learned from this photosensitivity, however, until the development of sensitive photodetectors and short duration high intensity light sources. These allowed Gibson, in pioneering discoveries in the mid to late 1950's (Gibson, 1956, 1959), to discover “Hb*,” a rapidly reacting form of hemoglobin, which we now associate with deoxy Hb in the tertiary relaxed “r” 9 state with the protein in the quaternary R …

Enantiomerically Enriched Α-Methyl Amino Acids. Use Of An Acyclic, Chiral Alanine-Derived Dianion With A High Diastereofacial Bias., David B. Berkowitz, Marianne K. Smith

David Berkowitz Publications

Hindered esters derived from N-benzoylalanine and the following chiral alcohols have been synthesized: (1) (−)-isopinocampheol; (2) (−)-trans-2-phenylcyclohexanol and (3) (−)-8-phenylmenthol. Sequential treatment of these esters with LDA (1.2 equiv.) and n-butyllithium (2.4 equiv.) at −78°C in THF generates the corresponding chiral dianions. Alkylation of each of these with benzyl bromide reveals that only the (−)-8-phenylmenthyl auxiliary confers a high diastereofacial bias upon its derivative dianion. In fact, that dianion (6) consistently displays diastereomeric ratios in the range of 89:11 to 94:6 for alkylations with a spectrum of nine alkyl halides. If one recrystallization step is …

Free Α-Oxiranyl Amino Acids, David B. Berkowitz, Michelle L. Pedersen

David Berkowitz Publications

Analogues of natural amino acids, in which the α-proton is replaced by an unsubstituted epoxide ring, are potential mechanism-based inhibitors for pyridoxal phosphate dependent enzymes.¹ Yet, free α-oxiranyl amino acids have remained elusive until now. The synthesis of an α-(phenyl-substituted)oxiranyl amino ester has been reported. However, the accessibility and stability of the corresponding free, zwitterionic α-oxiranyl amino acid remained an open question.⁹

Preparations Of Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group in an ethereal, polyethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydro-carbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme conditions.

Preparation Of Doped Polycarbynes, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Polycarbynes, such as doped polycarbynes, prepared from a soluble source of electrons and an organic monomer or co-monomer containing at least one carbyne group and, optionally, containing a doping agent, in an ethereal, poly ethereal, or hydrocarbon solvent are presented. A wide variety of arylcarbyne and/or alkylcarbyne monomers and co-monomers can be combined with a source of electrons soluble in an ethereal, polyethereal, or hydrocarbon solvent to form novel polycarbyne polymers. These polycarbyne polymers can be used to form synthetic diamond materials, fibers, and other materials that can withstand extreme con ditions.

A Study Of Euplotes Crassus Telomere Proteins And Related Genes, John Scott Perez

Department of Chemistry: Dissertations, Theses, and Student Research

A novel PCR technique used to amplify Euplotes crassus macronuclear chromosomes was developed to provide scientific proof that an Euplotes crassus 1.0 kb gene is not genetically related to an Oxytricha nova 1.8 kb β-telomere protein gene. Theories and experimental procedures associated with the development of this PCR technique were the product of research that will have a profound impact on future studies of telomere protein genes and telomeric DNA in a multitude of eukaryotic cells. The hypothesis that a β-telomere protein does not exist in Euplotes crassus was supported by the result of this study.

Expression of the recombinant …

Axial Asymmetry In The Nuclear Magnetic Resonance Spectra Of Deuterated Methyl Groups: An Alternative Explanation, Mieng-Hua Wann, Gerard S. Harbison

Gerard S. Harbison Publications

The deuterium nuclear magnetic resonance (NMR) powder spectra of methyl groups at ambient temperatures are invariably averaged by rotation or hopping about the C₃ axis. The canonical result for a perfectly threefold symmetric methyl is an axially symmetric Pake doublet whose splitting, in the case of perfect tetrahedral angles around the group, is averaged by a factor of exactly three. However, deuterium NMR spectra of methyl groups are often somewhat axially asymmetric, indicating a significant deviation either of the methyl group, or of its environment, from threefold symmetry. Previous explanations for this phenomenon have hinged on either an additional …

Electrocrystallization Of Strongly Adherent Brushite Coatings On Prosthetic Alloys, Jody G. Redepenning

Department of Chemistry: Faculty Publications

An electrolytic method for providing bone-emulating, phosphate coatings on prosthetic appliances. Such coatings serve to enhance bone fixation after implantation of the appliances. The method of the invention is an electrolysis process wherein the appliance to be coated is immersed in a phosphate-containing electrolyte to serve as the cathode of the electrolysis process. When current is applied to the electrolysis cell, the electrolyte solution, which includes calcium ions and dihydrogen phosphate ions, is caused to rapidly increase in (localized) pH proximate the cathode element. The localized pH increase creates a supersaturated local condition causing less soluble calcium phosphate salts to …

The Nuclear Hexadecapole Interaction Of Iodine-127 In Cadmium Iodide Measured Using Zero-Field Two Dimensional Nuclear Magnetic Resonance, Ming-Yuan Liao, Gerard S. Harbison

Gerard S. Harbison Publications

Two dimensional nuclear quadrupole correlation spectroscopy has been used to measure simultaneously the two nuclear spin transition frequencies for the iodine resonance of cadmium iodide at zero magnetic field. Because of the layer structure and resultant polymorphism in this substance, conventional zero-field NMR spectra are inhomogeneously broadened by several hundred kHz. However, the 2D spectra obtained by our method are subject only to homogeneous line-width, which for this compound is of the order of 5 kHz. This greatly increased precision allows more accurate evaluation of the nuclear hexadecapole coupling- in cadmium iodide; which we measure as 0.216 ±0.514 kHz (i.e., …

Highly Reactive Forms Of Zinc And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly produced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)₂. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.

Monte Carlo Simulation Of The Solid To Super Liquid Phase Transition Of Langmuir Monolayers Using Cross-Section Potentials, D.R. Swanson, Robert J. Hardy, Craig J. Eckhardt

Craig J. Eckhardt Publications

A cross-section potential which models the interaction of two planar objects of prescribed shape is developed and used to model the interactions of amphiphiles in vertical phases of Langmuir monolayers. The results of Monte Carlo simulations of an isobaric-isothermal ensemble show qualitative agreement with experiment. The model system undergoes a continuous, bound-to-free rotator transition between phases of the same symmetries as the solid (S) and super liquid (LS) phases exhibited by fatty acid films.

Brillouin-Scattering Study Of The Elastic Constants Of Phenothiazine Through The Phase Transition, J. Sartwell, Craig J. Eckhardt

Craig J. Eckhardt Publications

It has been proposed that single crystals of phenothiazine undergo a proper ferroelastic phase transition: Pnma(D_2h)→P2₁/c (C_2h). This premise is in conflict with Brillouin-scattering studies from both quasi- and high-symmetry longitudinal and transverse acoustic modes reported here. The C₅₅ elastic constant of phenothiazine as an orthorhombic crystal at ambient conditions shows no temperature dependence. The inelastic, light-scattering spectra support an order-disorder phase transition; no significantly unstable acoustic phonons were observed through the phase transition. Laser diffraction from structural domains reveals that the crystal is polysynthetically …

Piezomodulated-Raman-Spectroscopy Study Of The Phase Transition In Phenothiazine, J. Sartwell, Craig J. Eckhardt

Craig J. Eckhardt Publications

Single crystals of phenothiazine undergo a displacive order-disorder phase transition near 250 K. The microscopic mechanism of this transition is not clear owing to the complexity of a disordered lattice and the lack of direct mode-anharmonicity data. Unstable optical modes have been observed in phenothiazine and are regarded as coupled, by symmetry, to an acoustic mode that becomes overdamped through the phase transition. The latter is considered to have the primary role in the phase transition. This premise is in doubt, however, based on the optical-mode anharmonicity directly observed by uniaxial-piezomodulation-Raman-spectroscopy results presented here. Anharmonic responses are observed in the …

Investigation Of The Β-Γ Phase Transition In Single Crystal Malononitrile By Polarized Raman Spectroscopy, S.J. Bonafede, Craig J. Eckhardt

Craig J. Eckhardt Publications

Temperature dependent, polarized Raman spectra in the lattice mode region for sublimed, single crystal malononitrile through the β-γ phase transition (T_c=294.7 K) are reported. Symmetry assignments and frequencies of vibrational modes are made and compared to previous studies. Nine out of 12 possible lattice modes are observed in each phase with three of the observed modes being affected by the phase transition. The temperature dependence of these three affected modes is attributed to cyano group and molecular dipole interactions between molecules in the crystal. The behavior of malononitrile through the β-γ phase transition is analogous to the …

Temporary Negative-Ion Resonances In The Nio(100) High-Resolution Electron-Energy-Loss Spectrum , K.W. Wulser, Marjorie Langell

Marjorie A. Langell Publications

The NiO(100) Fuchs-Kliewer phonon spectrum has been investigated by high-resolution electron-energy-loss spectroscopy (HREELS) at beam energies of 0.8–17 eV and the intensity distribution of the phonons relative to the dielectric properties of the NiO substrate has been considered. Over most of the range, the spectrum is well behaved, with the single-loss phonon energy at -70.5 meV and multiple excitations decreasing according to the predicted Poisson distribution. At 5.0-, 8.5-, and 13.5-eV primary beam energies, however, a substantial resonant enhancement in the phonon cross section is observed. The enhancement is accompanied by a shift from the Poisson intensity distribution to favor …

Processes For Producing Doxorubicin, Daunomycinone, And Derivatives Of Doxorubicin, Desmond M. S. Wheeler

Department of Chemistry: Faculty Publications

To produce doxorubicin and its analogues methyl 3alpha, 5alpha-dihydroxy-5beta-(trimethylsilylethynyl)- 2alpha-nitromethylcyclohexane-1beta-carboxylate acetonide is condensed with 1,4-dihydro-4,4,5-trimethoxy-1-oxonaphthalene in the presence of 1,8-diazabicyclo-5.4.0]undec-7-ene in an aprotic solvent to produce 3-(2beta-carbomethoxy-4-beta-ethynyl-4-alpha, 6alpha-(di-O-isopropylidenyl)cyclohexanyl-1-yl)-nitromethyl-4,4,5-trimethoxy-1-oxo-1,2,3,4-tetrahydronaphthalene; which is cyclized to produce 9beta ethynyl-12-hydroxy-7alpha, 9alpha-(di-O-iso propylidenyl)-6-nitro-4,5,5-trimethoxy-5,5a,6- 6a,7,8,9,10,10a,11-decahydro -11-naphthacenone. The decahydro-11-naphthacenone is converted to 7alpha 9alpha,(di-O-isopropyl-idenyl)-4,5-dimethoxy-9beta ethynyl-12-hydroxy-6-nitro-6,6a,7,8,9,10,10a, 11 octahydro-11, -naphthacenone. The octahydro-11 naphthacenone is oxidized to 7alpha-9alpha, (di-O-iso propyl-idenyl)-9beta-ethynyl-11-hydroxy-4-methoxy-6- nitro-7,8,9,10-tetrahydro-5,12-naphthacenedione which is converted to 6-desoxy-6-nitrodaunomycinone, daunomycinone and related 6-substituted analogues of daunomycinone.

Preparation And Use Of (2-Butene-1,4-Diyl)Magnesium Complexes In Organic Synthess, Reuben D. Rieke

Department of Chemistry: Faculty Publications

The magnesium complexes of cyclic hydrocarbons, such as 1,2-dimethylenecycloalkanes, are readily prepared in high yields using highly reactive magnesium. Reactions of these (2-butene-1,4-diyl)magnesium reagents with electrophiles such as dibromoalkanes, alkyl ditosylates, or bromoalkylnitriles serve as a convenient method for synthesizing spirocyclic systems. Significantly, spirocarbocycles prepared by this method contain functional groups such as the exocyclic double bond or a keto group in one of the rings which could be used for further elaboration of these molecules. Furthermore, fused bicyclic systems containing a substituted five-membered ring can be conveniently prepared at high temperatures by the reactions of (2-butene-1,4- diyl)magnesium complexes with …

Soluble Highly Reactive Form Of Calcium And Reagents Thereof, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A soluble highly reactive form of calcium, prepared from Ca(II) salts and a reducing agent in ethereal, polyethereal, or hydrocarbon solvents, is presented. This form of calcium can be used in the preparation of organocalcium reagents. The organocalcium reagents resulting from the reaction of the soluble highly reactive calcium with organic compounds containing either halide, cyanide, a 1,3-diene, or a polyunsaturated functionality, are stable, useful reagents for organic synthesis. The organocalcium halide reagents undergo Grignard-type reactions. They also undergo reactions with Cu(I) salts to form organocalcium cuprate reagents. The organocalcium cuprate reagents undergo a variety of cross-coupling reactions. The soluble …

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 …

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 …

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) …

Viscosities Of Vegetable Oils And Fatty Acids, Hossein Noureddini, B. C. Teoh, L. Davis Clements

Papers in Biomaterials

Data for viscosity as a function of temperature from 24 to 110°C (75 to 230°F) have been measured for a number of vegetable oils (crambe, rapeseed, corn, soybean, milk- coconut, lesquerella) and eight fatty acids in the from Cg to CZZ The viscosity measurements were performed according to ASTM test methods D 445 and D 446. Several correlations were fitted to the experimental data. Correlation constants for the best fit are presented. The range of temperature in which the correlations are valid is from 24°C (75°F), or the melting point of the substance, to 110°C (230°F). The correlation constants are …

Nio(100) Valence-Band Density Of States During Hydrogen Reduction , K.W. Wulser, B.P. Hearty, Marjorie Langell

Marjorie A. Langell Publications

Photoelectron spectroscopy with incident photons of 40–120 eV has been used to determine the valence-band structure of NiO(100) as the surface undergoes slow hydrogen reduction. Low pressure and moderate temperature conditions (1.3×10^-2 Pa and 625 K) allow oxygen to be removed from the near-surface region with a minimal disruption in the NiO(100) substrate. Both NiO(100) ultraviolet photoemission spectroscopy (UPS) and low-energy electron-diffraction features persist at NiO(100) reduced surfaces throughout the reduction process. In addition, reduced nickel features slowly grow into the UP spectra, with the most intense peak found in the NiO band gap. Chemisorbed hydrogen, hydroxyls, and oxygen …

Three-Dimensional Solution Structure Of Human Interleukin-4 By Multidimensional Heteronuclear Magnetic Resonance Spectroscopy, Robert Powers, Daniel S. Garrett, Carl J. March, Eric A. Frieden, Angela M. Gronenborn, G. Marius Clore

Department of Chemistry: Faculty Publications

The three-dimensional solution structure of recombinant human interleukin-4, a protein of 133 residues and 15.4 kilodaltons that plays a key role in the immune and inflammatory systems, has been solved by multidimensional heteronuclear magnetic resonance spectroscopy. The structure is dominated by a left-handed four-helix bundle with an unusual topology comprising two overhand connections. The linker elements between the helices are formed by either long loops, small helical turns, or short strands. The overall topology is remarkably similar to that of growth hormone and granulocyte-macrophage colony stimulating factor, despite the absence of any sequence homology, and substantial differences in the relative …

The Eukaryotic Initiation Factor 2-Associated 67-Kda Polypeptide (P67) Plays A Critical Role In Regulation Of Protein Synthesis Initiation In Animal Cells, Manas K. Ray, Bansidhar Datta, Arup Charkraborty, Ansuman Chattopadhyay, Susanne Meza-Keuthen, Naba K. Gupta

Department of Chemistry: Faculty Publications

The eukaryotic initiation factor 2 (eIF-2)- associated 67-kDa polypeptide (p⁶⁷) isolated from reticulocyte lysate protects the eIF-2 α subunit from eIF-2 kinase-catalyzed phosphorylation and promotes protein synthesis in the presence of active eIF-2 kinases. We have now studied the roles of p⁶⁷ and eIF-2 kinases in regulation of protein synthesis using several animal cell lysates and an animal cell line (KRC-7) in culture under various growth conditions. The results are as follows. (i) Both p⁶⁷ and eIF-2 kinase(s) are present in active forms in all animal cells under normal growth conditions and p^{67 …}

Improved Recovery Of A Radlolabeled Peptide With An Albumin-Treated Reversed-Phase Hplc Column, David S. Hage, Robert L. Taylor, Pai C. Kao

David Hage Publications

Reversed-phase high-performance liquid chromatography (RP-HPLC) is an important tool in the purification of radiolabeled peptides and proteins for immunoassay. However, for some proteins and peptides it is difficult to achieve reproducible behavior in RP-HPLC because of the low recovery of these compounds. Factors that can be varied to improve recovery include the strength or pH of the mobile phase, the chain length and spacing of groups on the reversed-phase support, and the flow rate or steepness of the elution gradient (1-5). ... In summary, we obtained better recovery and more reproducible chromatographic behavior for labeled 1-34 PTHrP with an albumin-pretreated …

Intact Parathyroid Hormone: Performance And Clinical Utility Of An Automated Assay Based On High-Performance Immunoaffinity Chromatography And Chemiluminescence Detection, David S. Hage, Bob Taylor, Pai C. Kao

David Hage Publications

The performance and clinical utility of an automated assay of intact parathyroid hormone (parathyrin, PTH) are evaluated. The method is based on the extraction of PTH from plasma by an HPLC column containing immobilized anti-(44-68 PTH) antibodies. The PTH retained is detected with a postcolumn reactor and use of anti-(1--34 PTH) chemiluminescent-labeled antibodies. The total cycle time of the assay is 6.5 mm per injection after a 1-h incubation.The lower limit of detection for PTH in a 66-pL plasma sample was 0.5 pmol/L based on peak heights and 0.2 pmol/L based on peak areas. Mean analytical recovery for PTH added …