Chemistry Commons^™

Reply To "Comment On 'Kinetic-Energy Density Functional For A Special Shape-Invariant Potential Of A One-Dimensional Two-Level System'", Jiushu Shao, John J. Stezowski

John J. Stezowski Publications

For a harmonic potential, which is the special shape-invariant potential discussed in our paper [1], the relation between the ground state and the first-excited-state wave functions [Eq. (2)] should be . . .

Therefore, we have shown that one cannot find a closed form of the kinetic-energy density for the harmonic oscillator.

Use Of Affinity Chromatography In Developing Acridinium Ester-Labeled Antibodies For An Immunometric Assay Of Parathyrin, David S. Hage, Bob Taylor, Pat Schryver, Pai C. Kao

David Hage Publications

In developing an immunometric assay of intact parathyrin (parathyroid hormone, PTH), we found that affinity chromatography is a useful tool in purifying and optimizing the labeling conditions for acridinium ester-labeled antibodies. ... In summary, affinity chromatography was found to be useful in the purification of acridinium ester-labeled antibodies, particularly for removing denatured antibodies from the prepared label and for monitoring the amount of active labeled antibodies produced.

In Vitro Assembly Of Apophytochrome And Apophytochrome Deletion Mutants Expressed In Yeast With Phycocyanobilin, Lily Deforce, Ken-Ichi Tomizawa, Naoko Ito, Dave Farrens, Pill-Soon Song, Masaki Furuya

Department of Chemistry: Faculty Publications

Recombinant pea type I phytochrome apoprotein expressed in yeast is shown to assemble in vitro with phycocyanobilin to produce a photoreversible phytochromelike adduct. As an initial investigation of the amino acid sequence requirements for chromophore incorporation, three phyA gene product deletion mutants were produced in yeast. Truncation of the N-terminal tail to residue 46 demonstrates that this region is not critical to bilin attachment, but a deletion mutant lacking 222 amino acids from the N terminus failed to yield holophytochrome in vitro, under the same conditions. A mutant comprising a deletion of the C terminus to residue 548 …

Kinetic-Energy Density Functional For A Special Shape-Invariant Potential Of A One-Dimensional Two-Level System , Jiushu Shao, John J. Stezowski

John J. Stezowski Publications

By introducing the concept of supersymmetry to quantum mechanics, several authors have shown that exactly soluble potentials, including all those well known, are easily constructed. Is the kinetic-energy density functional corresponding to these potentials a simple form? We show that the answer is no, even to the simplest one, the harmonic potential, if one builds the kinetic-energy density functional from the reduced density matrix.

Statics And Dynamics Of Organic Charge-Transfer Crystals: The Orientational Phase Transition In A-Tcnb, Karl-Heinz Brose, Tadeusz Luty, Craig J. Eckhardt

Craig J. Eckhardt Publications

Crystal potential energy calculations and lattice dynamical calculations are presented for the high-temperature and low-temperature phases of the charge-transfer complex crystal of anthracene with 1,2,4,5-tetracyanobenzene using the method of atom–atom potentials. For several different sets of the “exp-6'' potential parameters the crystal energy was minimized with respect to the lattice constants and orientations and positions of the molecules in the unit cell. These calculations show good agreement with the experimental values. The equilibrium crystal structures were used to calculate the lattice dynamics in the harmonic approximation for both crystal modifications. In the phonon dispersion curves lattice modes were discovered that …

Semiempirical Determination Of Molecular Motions Associated With Phonon Modes In Molecular Crystals, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

An approach using piezomodulated Raman scattering is presented which permits determination of the molecular motions associated with the eigenmodes of molecular crystals. When coupled with a lattice dynamical calculation for the eigenmodes, the experiment can be used to validate the calculation. The case of 1,2,4,5-tetrabromobenzene is treated and it is shown that the phase relations of the piezomodulated Raman signals confirm the calculated eigenmodes. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

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; …

Semiempirical Determination Of Intermolecular Anharmonicity In Molecular Crystals: The Case Of 1,2,4,5-Tetrabromobenzene, R.C. Dye, Craig J. Eckhardt

Craig J. Eckhardt Publications

The molecular crystal 1,2,4,5-tetrabromobenzene (TBB) has been studied using Brillouin scattering and lattice dynamical calculations. A method for mapping acoustic mode anharmonicity is developed that exhibits substantial directional behavior and correlates well with the directions of the molecular movements associated with the phase transition. It is shown that by comparing the calculated sound velocities with the experimental values, insight can be gained into the displacive phase transition and the lattice dynamics of TBB. The sound velocities are plotted for three crystallographic planes containing the crystal axes. The relationships between sound velocities and lattice dynamics are discussed. The phonon dispersion curves …

Light Scattering Apparatus For Angular Dependent Studies Of Anisotropic Materials, R.C. Dye, J. Sartwell, Craig J. Eckhardt

Craig J. Eckhardt Publications

An improved method for light scattering from acoustic phonons in small, low-symmetry solids is described. This instrumentation greatly facilitates the determination of elastic constants in highly anisotropic materials. Elastic scattering can be greatly reduced so that weaker phonon modes can be observed. Errors associated with the determination of the polarization directions of an anisotropic material are minimized by considering crystal optics. Review of Scientific Instruments is copyrighted by The American Institute of Physics.

Assignment Of The Raman Active Lattice Vibrations In Various Phases Of 1,2,4,5 Tetrabromobenzene And 1,2,4,5-Tetrachlorobenzene Crystals, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Results of polarized Raman spectroscopy are reported and used to obtain complete assignment of the optical lattice modes of 1,2,4,5-tetrabromobenzene crystals for both the beta and gamma phases. Similar information is provided for the beta phase of 1,2,4,5-tetrachlorobenzene crystal. The results are compared with lattice-dynamics calculations. Discrepancies with previously reported measurements and calculations are discussed and rationalized. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

A Complete Set Of Elastic Constants Of Crystalline Anthracene By Brillouin Scattering, R.C. Dye, Craig J. Eckhardt

Craig J. Eckhardt Publications

All 13 elastic constants of a vapor grown, uncut, anthracene single crystal were determined from acoustic phonon velocities obtained by the Brillouin scattering method. The phonon velocities are plotted for three crystallographic planes containing the crystal axis. The relationships between phonon velocities and lattice dynamics are discussed. A minimizing procedure is introduced for converting phonon velocities of low symmetry systems into elasticity coefficients. This is shown to have several advantages over previous methods used. The results are compared with those obtained by previous studies of anthracene elastic constants.

Translational-Rotational Modes In Noncentrosymmetric Lattices: A Lattice-Dynamical Interpretation Of The Phenanthrene Phase Transition, R. Kulver, Craig J. Eckhardt

Craig J. Eckhardt Publications

A lattice-dynamical study has been used to elucidate the mechanism of the phase transition in phenanthrene. The calculation is consistent with the known lattice energy and crystal structure. Combination of experimental results with the calculated phonon dispersion curves and eigenmode symmetries yields a dynamic mechanism for the transition based on increasing density of higher-frequency modes upon approach to the transition temperature to the high-temperature phase. This motion, which may be associated with motion of hydrogen atoms in the molecule, confers a more three-dimensional character to the interactions and correlates well with the observed change in heat capacity.

Roles Of A 67-Kda Polypeptide In Reversal Of Protein Synthesis Inhibition In Heme-Deficient Reticulocyte Lysate, Bansidhar Datta, Debopam Chakrabarti, Ananda L. Roy, Naba K. Gupta

Department of Chemistry: Faculty Publications

During heme deficiency in reticulocyte lysates, the heme-regulated protein synthesis inhibitor, HRI, phosphorylates the a subunit of eukaryotic initiation factor 2 (eIF-2) and thus inhibits protein synthesis. Two factors, eIF-2 and a reticulocyte-lysate supernatant factor that we term RF, reverse this inhibition. We now report the following. (i) An active eIF-2 preparation contained, in addition to the three subunits (α,β, and γ), a 67-kDa polypeptide. Pretreatment of eIF-2 with polyclonal antibodies against either isolated a subunit or 67-kDa polypeptide almost completely inhibited the reversal activity. Upon further fractionation, three-subunit eIF-2 and the 67-kDa polypeptide were resolved. Neither the …

Comment On ‘‘Relations Between Microscopic And Macroscopic Lowest-Order Optical Nonlinearities Of Molecular Crystals With One- Or Two-Dimensional Units’’, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

An algebraic error in an earlier paper [J. Zyss and J. L. Oudar, Phys. Rev. A 26, 2028 (1982)] led to an interpretation regarding the desirable polarizability characteristics of a molecule for second-harmonic generation in crystals which is opposite to that actually desired. Optimum response is obtained from crystals comprised of molecules with significant in-plane polarizabilities.

Optimization Of Effective Nonlinear Coefficients For Second-Harmonic Generation In Molecular Crystals , K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Conditions for the design of organic solids capable of optimum nonlinear optical behavior are investigated. Generalized expressions describing optimum phase-matching conditions in crystals of monoclinic symmetry and having one-dimensional hyperpolarizabilities are obtained. The results are applied to specific organic molecular solids. An anisotropic in-plane molecular polarizability is shown to provide the best condition for second-harmonic generation in these systems.

Mode Anharmonicity In Molecular Crystals Studied By Piezomodulated Raman Spectrosocpy , K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Piezomodulated Raman scattering is used to determine the extent of anharmonicity, the phonon-phonon coupling, and the presence of modes involved in the phase transition of 1,2,4,5-tetrabromobenzene. The experiments support earlier theoretical predictions and demonstrate that piezomodulated Raman spectroscopy is an important new approach to the experimental study of lattice dynamics.

Assignment Of The Lattice Modes In Tcnq0 Single Crystals, K.M. White, K.-H. Brose, Craig J. Eckhardt

Craig J. Eckhardt Publications

A complete assignment of the six librational modes of the TCNQ⁰ crystal has been made employing both polarized Raman spectroscopic measurements and lattice dynamical calculations. Agreement between theory and experiment is good and modes at 40.5, 74.5, and 96 cm^-1 are assigned as A_g active and those at 63, 75.5, and 104 cm^-1 are B_g active. The lattice modes are found to be clearly separated from the molecular modes. The study emphasizes the importance of crystal optics and quality in the measurement of the polarized Raman spectra of biaxial crystals. The Journal of Chemical Physics …

Redox Chromophore Compounds And Electrodes Of Metal Containing Substituted Bipyridines, Cecil M. Elliott, Jody G. Redepenning

Department of Chemistry: Faculty Publications

Chromophoric compounds, each having a wide range of distinct color changes in response to changes in the oxidation states thereof, are provided in the form of polymerizable monomers, and polymers thereof, of certain metal containing, and electron group substituted, 2,2'-bipyridine compounds.
United States Patent Number 4,611,890

Crystal Structure And Charge Transfer Energies Of Complexes Of The Donor Biphenylene With The Acceptors Tcnb And Pmda, John J. Stezowski, Rolf-Dietrich Stigler, Norbert Karl

John J. Stezowski Publications

Biphenylene:tetracyanobenzene (BPN:TCNB), C₁₂H₈:C₁₀H₂N₄, crystallizes in a monoclinic lattice, space group P2₁/a, Z = 2, with a = 15.215(2) Å, b = 7.260(1) Å, c = 7.573(1) Å, β = 90.05(1)° at 296 K. The BPN donor and TCNB acceptor molecules form two symmetry-related mixed linear [001] stacks with the donor and acceptor molecular planes tilted to each other (within the individual stacks) at an angle of Φ = 7.6°. Biphenylene:pyromellitic-dianhydride (BPN:PMDA), C₁₂H₈:C₁₀H₂O₆, crystallizes in two …

The Association Of Nadph With The Guanine Nucleotide Exchange Factor From Rabbit Reticulocytes: A Role Of Pyridine Dinucleotides In Eukaryotic Polypeptide Chain Initiation, Jaydev N. Dholakia, Timothy C. Muesser, Charles L. Woodley, Lawrence J. Parkhurst, Albert J. Wahba

Department of Chemistry: Faculty Publications

The guanine nucleotide exchange factor (GEF) was purified to apparent homogeneity from postribosomal supernatants of rabbit reticulocytes by chromatography on DEAE-celiulose and phosphocellulose, fractionation by glycerol gradients, and chromatography on Mono S and Mono Q (Pharmacia). At the Mono S step GEF is isolated as a complex with the eukaryotic polypeptide chain initiation factor 2 (eIF-2) and is separated from this factor by column chromatography on Mono Q. An emission spectrum characteristic of a reduced pyridine dinucleotide was observed when GEF was subjected to fluorescence analysis. By both coupled enzymatic analysis and chromatography on reverse-phase or Mono Q columns, the …

Piezomodulated Raman Spectroscopy Of Molecular Crystals: An Experimental Method For Study Of The Anharmonic Properties Of Solids, T. Luty, Craig J. Eckhardt

Craig J. Eckhardt Publications

Consideration of phonon-phonon coupling induced by strain serves as impetus for developing a theoretical structure for piezomodulated Raman spectroscopy which can be used for experimental realization of the coupling. The direct relation of the coupling constant to generalized stress Gruneisen parameters is shown. These describe the crystal's anharmonic properties such as the thermal expansivity and the temperature dependence of the phonon energies. Numerical calculations are performed for anthracene crystal which exemplify the use of the stress Gruneisen parameters as sensitive measures of anisotropy of intermolecular interactions. Further development shows how the measurement can be used to determine these parameters and …

Influence Of Crystal Fields On The Quasimetallic Reflection Spectra Of Crystals: Optical Spectra Of Polymorphs Of A Squarylium Dye, M. Tristani-Kendra, Craig J. Eckhardt

Craig J. Eckhardt Publications

The reflection and Kramers–Kronig absorption spectra have been obtained from the monoclinic and triclinic polymorphs of a squarylium dye, 2,4-bis(4-diethylamino-2-hydroxy phenyl) cyclobutadienediylium-1,3-diolate. The extremely different optical responses were found to arise from two molecular singlet transitions of essentially long axis polarization. Successful application of a four oscillator molecular exciton–polariton theory required the use of point charge densities rather than point dipoles in an extension of the theory which employed both interactions between the two singlets as well as a frequency dependent lattice damping. An intermolecular charge transfer transition is also assigned. The Journal of Chemical Physics is copyrighted by The …

Modulated Piezoreflectivity And The Photoelasticity Of Molecular Crystals, T. Luty, Craig J. Eckhardt

Craig J. Eckhardt Publications

Analysis of the optical response of a molecular crystal undergoing an external, periodic modulation is presented in terms of classical dipole theory. The case of modulated strain is treated in particular and identification of such strain with acoustic phonons with q=0 permits use of lattice dynamical theory to elucidate the acoustic phonon–exciton interaction. It is shown that extrema in the piezomodulated reflectivity (PMR) locate transverse and longitudinal exciton–polariton frequencies under specific experimental conditions. Model calculations demonstrate the great difference in the PMR for strong and weakly coupled systems. Relation of the PMR intensity to the elasto-optic coefficients and the storage …

Protein Synthesis In Rabbit Reticulocytes: A Study Of The Mechanism Of Action Of The Protein Factor Rf That Reverses Protein Synthesis Inhibition In Heme-Deficient Reticulocyte Lysates, M. Grace, M. Bagchi, F. Ahmad, T. Yeager, C. Olson, I. Chakravarty, N. Nasrin, A. Banerjee, N. K. Gupta

Department of Chemistry: Faculty Publications

A eukaryotic initiation factor 2 (eIF-2)-ancillary protein factor Co-eIF-2 promotes displacement of GDP from eIF-2GDP and facilitates ternary complex (Met-tRNA_f• eIF-2-GTP) formation in the presence of Mg²⁺. Heme-regulated protein synthesis inhibitor, HRI, phosphorylates the α-subunit of eIF-2 and thus inhibits ternary complex formation as Co-eIF•2 does not displace GDP from eIF-2α(P)•GDP. RF, a high molecular weight cell supernatant factor, reverses protein synthesis inhibition in heme-deficient reticulocyte lysates and also reverses HRI inhibition of ternary complex formation. RF contains Co-eIF•2 activity. In addition, an active RF preparation contains excess α-subunit of eIF-2 in the free and unphosphorylated …

Some Plant Leaves Have Orientation-Dependent Epr And Nmr Spectra, Douglas C. Mccain, Ted C. Selig, University Of Illinois At Urbana-Champaign, John L. Markey

Department of Chemistry: Faculty Publications

Proton nuclear magnetic resonance (¹H NMR) spectra of leaves from 50 plant species were obtained at a spectrometer frequency of 470 MHz. Water present in leaf samples gives rise to characteristic spectral patterns. Most species show only one broad ¹H NMR peak; however, the leaves of some plants display complex, orientation-dependent spectra in which a common three-line pattern is discerned. The pattern varies with the angle between the leaf surface and the external magnetic field. Proton relaxation measurements show the presence of at least two water compartments in the leaves. The compartments are responsible for different components …

The Binding Of Ribosomal Protein Si To Si-Depleted 30s And 70s Ribosomes. A Fluorescence Anisotropy Study Of The Effects Of Mg2+, Dixie J. Goss, Lawrence J. Parkhurst, Arkesh M. Mehta, Albert J. Wahba

Lawrence Parkhurst Publications

We have determined the equilibrium constants for the binding of AEDANS-labelled Si to Sl-depleted 30S and 70S ribosomes. For “tight” ribosomes, the association of S1 increases with the sixth power of Mg²⁺ concentration, but for 30S subunits and "loose" ribosomes, there is virtually no dependence of the association on Mg²⁺ over the same concentration range, 2-1O mM in Mg²⁺. The binding of S1 to 70S ribosomes at 10 mM Mg is stabilized by 2 kcal/mol compared to the binding to 30S subunits. When intact Si binds to tight ribosomes, the fluorescence anisotropy is that for virtually …

The Kinetics Of Oxidation Of Various Organic Substrates By Potassium Ferrate, Ronald Lee Bartzatt

Department of Chemistry: Dissertations, Theses, and Student Research

Potassium ferrate is a strong oxidizing agent and highly soluble in water. These properties may allow it to oxidize a wide variety of aqueous organic compounds to simpler organic compounds. The kinetics and final products of typical ferrate oxidations must be studied before conclusions about its efficiency can be drawn.

The ferrate oxidation of diethylsulfide and 2,2-thiodiethanol were studied in a pH range of 8.90 to 9.90. Their plots of Log k_s versus pH are essentially parallel and show mixed-order characteristics. The order of dependence of diethylsulfide on [H⁺] is 0.708. The order of dependence of 2,2-thiodiethanol …

Protein Synthesis In Rabbit Reticulocytes: Characteristics Of The Protein Factor Rf That Reverses Inhibition Of Protein Synthesis In Heme-Deficient Reticulocyte Lysates, Michael Grace, Robert O. Ralston, Ambica C. Banerjee, Naba K. Gupta

Department of Chemistry: Faculty Publications

During heme deficiency in reticulocyte lysates, the heme-regulated translational inhibitor of protein synthesis (HRI) is activated and shuts off protein synthesis. In partial reactions, HRI phosphorylates the M_r 38,000 subunit (α subunit) of eukaryotic initiation factor 2 (eIF-2), which forms a ternary complex, Met-tRNA_f•eIF-2•GTP. The eIF-2α(P) thus formed is not recognized by two eIF-2 ancillary factors, Co-eIF-2B (which promotes the dissociation of the ternary complex at high Mg²⁺) and Co-eIF-2C (which reverses the inhibition of ternary complex formation), and thus, is presumably inactive in peptide chain initiation. A protein factor, designated RF, which reverses inhibition …

Piezomodulation Spectroscopy Of Molecular Crystals. Ii. The Pyromellitic Dianhydride Anthracene Electron Donor–Acceptor Complex, J. Merski, Craig J. Eckhardt

Craig J. Eckhardt Publications

Piezomodulated reflection spectra are presented for the crystalline complex of pyromellitic dianhydride–anthracene. Two differently polarized charge transfer transitions are found and their strain sensitivities are obtained. The role of the charge transfer interaction in determining the magnitude of the piezomodulation is assessed. The piezomodulation spectra are found to have the response expected for an oriented gas. Significant enhancement of structure is also observed and is correlated with structure observed at 20 K.

Piezomodulation Spectroscopy Of Molecular Crystals. Iii. The First Singlet System Of Anthracene, J. Merski, Craig J. Eckhardt

Craig J. Eckhardt Publications

The polarized piezoreflection spectra of the first singlet system of anthracene and their Kramers-Kronig transforms are reported. Exciton energy strain shifts are reported for the b-polarized and for the ac-polarized factor group components. These values are shown to be in good agreement with related experimental data and with theoretical calculations. The piezomodulation spectra significantly enhance structure and are also sensitive to the extent of crystal coupling. Deviations in the measured spectra are observed in the a-polarized spectra from that calculated for the logarithmic derivative. These variances are attributed to coupling with the second singlet of anthracene or …