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1995

Chemistry

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Articles 1 - 30 of 90

Full-Text Articles in Physical Sciences and Mathematics

Multifragmentation In E/A=35 Mev Collisions: Evidence For A Coulomb Driven Breakup?, M. D'Agostino, G. J. Kunde, P. M. Milazzo, J. D. Diniu, M. Bruno, N. Colonna, M. L. Fiandri, C. K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, W. C. Hsi, M. Huang, M. A. Lisa, W. G. Lynch, P. F. Mastinu, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, R. Rui, C. Schwarz, M. B. Tsang, G. Vannini, C. Williams Dec 1995

Multifragmentation In E/A=35 Mev Collisions: Evidence For A Coulomb Driven Breakup?, M. D'Agostino, G. J. Kunde, P. M. Milazzo, J. D. Diniu, M. Bruno, N. Colonna, M. L. Fiandri, C. K. Gelbke, T. Glasmacher, F. Gramegna, D. O. Handzy, W. C. Hsi, M. Huang, M. A. Lisa, W. G. Lynch, P. F. Mastinu, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, R. Rui, C. Schwarz, M. B. Tsang, G. Vannini, C. Williams

Faculty Publications

Multifragment disintegrations have been measured for central Au+Au collisions at EA=35 MeV. Fragment emission occurs predominantly at low center of mass energies of about EA≈5 MeV, consistent with a Coulomb dominated breakup of a single source. Mean fragment multiplicities of ⟨NIMF⟩≈10.8 are extracted after correction for the detection efficiency. The fragment charge distributions decrease much more gradually than expected from scaling laws recently applied to the extraction of critical exponents for the nuclear liquid-gas phase transition from nuclear collisions.


Croatian Symposium Of Chemistry And Macromolecular Chemistry, Otto Vogl, Zvonimir Janovic Dec 1995

Croatian Symposium Of Chemistry And Macromolecular Chemistry, Otto Vogl, Zvonimir Janovic

Emeritus Faculty Author Gallery

No abstract provided.


Polymer Science In Australia Iv. Universities In Victoria And Southern Australia, Otto Vogl, David Solomon, Ezio Rizzardo, Robert A. Shanks, David Williams Dec 1995

Polymer Science In Australia Iv. Universities In Victoria And Southern Australia, Otto Vogl, David Solomon, Ezio Rizzardo, Robert A. Shanks, David Williams

Emeritus Faculty Author Gallery

No abstract provided.


52. Bengt Ranby, Otto Vogl Dec 1995

52. Bengt Ranby, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


Synthesis And Characterization Of A Water-Soluble Metallopeptide That Resembles A Parallel Beta-Pleated Sheet, Michael Y. Ogawa, Alexei B. Gretchikhine, Sunil-Datta Soni, Steven M. Davis Dec 1995

Synthesis And Characterization Of A Water-Soluble Metallopeptide That Resembles A Parallel Beta-Pleated Sheet, Michael Y. Ogawa, Alexei B. Gretchikhine, Sunil-Datta Soni, Steven M. Davis

Chemistry Faculty Publications

The title metallopeptide consists of two divalinyl peptides attached to the carboxylate groups of the ruthenium polypyridyl complex. [Ru(bpy)(2)L](2+): bpy = 2,2'-bipyridine; L = 3,5-dicarboxy-2,2'-bipyridine. The charged ruthenium complex is water soluble and is shown by variable temperature, and 2-D NMR to consist a parallel arrangement of interacting, extended peptide strands that ir reminiscent of the beta-sheet structure. Circular dichroism results support this assignment.


Prompt And Sequential Decay Processes In The Fragmentation Of 40 Mev/A 20ne Projectiles, R. J. Charity, L. G. Sobotka, N. J. Robertson, D. G. Sarantites, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, W. C. Hsi, M. J. Huang, W. G. Lynch, C. P. Montoya, Graham F. Peaslee, C. Schwarz, M. B. Tsang Dec 1995

Prompt And Sequential Decay Processes In The Fragmentation Of 40 Mev/A 20ne Projectiles, R. J. Charity, L. G. Sobotka, N. J. Robertson, D. G. Sarantites, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, W. C. Hsi, M. J. Huang, W. G. Lynch, C. P. Montoya, Graham F. Peaslee, C. Schwarz, M. B. Tsang

Faculty Publications

The fragmentation of E/A=40 MeV Ne20 projectiles into exit channels containing only p, d, t, He3, α, He6, Li6, and Li7fragments has been investigated. Relative shifts between the average longitudinal velocity of each fragment type were measured with Sn120 and Au197 targets. A post-breakup Coulomb acceleration component of these shifts was isolated. Its magnitude indicates that the projectile broke up while in near contact with the target. On the other hand, correlations between projectile fragments indicate that a significant fraction of these fragments are produced by the sequential decay of long- and short-lived unstable intermediates. A fully sequential decay process, …


Upper-Tropospheric Aerosol Sampled During Project Fire Ifo Ii, Donald E. Hagen, Josef Podzimek, Max B. Trueblood Dec 1995

Upper-Tropospheric Aerosol Sampled During Project Fire Ifo Ii, Donald E. Hagen, Josef Podzimek, Max B. Trueblood

Physics Faculty Research & Creative Works

Aerosols can play a role in the cloud formation process through the heterogeneous nucleation mechanism, and in turn, once formed, cirrus clouds can impact the ambient aerosol through scavenging and other collection mechanisms. University of Missouri aerosol sampling facilities were employed on aircraft for in situ collection and characterization of the particulates near cirrus cloud level. Tandem differential mobility analyzer and impactor techniques were used to measure aerosol size distribution, hydration capability, and particle composition information. Evidence of aerosol layering was observed near the tropospause, and there was a tendency toward depletion of the ambient aerosol at both ends of …


Coincidence Correlations Between Light Charged Particles In The Matched Reactions 905 And 1030 Mev121sb + 27al And 550 And 750 Mev 86kr + 63cu, Winifred E. Parker, Morton Kaplan, David J. Moses, John M. Alexander, Roy B. Lacey, Dalva M. De Castro Rizzo, J. Bolger, A. Narayanan, Graham F. Peaslee, D. G. Popescu Nov 1995

Coincidence Correlations Between Light Charged Particles In The Matched Reactions 905 And 1030 Mev121sb + 27al And 550 And 750 Mev 86kr + 63cu, Winifred E. Parker, Morton Kaplan, David J. Moses, John M. Alexander, Roy B. Lacey, Dalva M. De Castro Rizzo, J. Bolger, A. Narayanan, Graham F. Peaslee, D. G. Popescu

Faculty Publications

Coincidence measurements have been made between and a second particle () produced in the reactions 905 and 1030 MeV and 550 and 750 MeV . All four of the reactions lead to composite systems of 149Tb∗ or 148Gd∗ which facilitates comparisons of matched reactions. In the two reactions and the 550 MeV reaction, the particle-particle coincidences are dominated by processes that lead to evaporation residues. In the 750 MeV reaction, about half of the 1H and 4He are associated with evaporation residue production. These particle-particle coincidences arise from cross sections that are subsets of the total evaporation residue cross sections. …


Evidence For The Reducibility Of Multifragment Emission To An Elementary Binary Emission In Xe-Induced Reactions, K. Tso, L. Phair, A. Colonna, W. Skulski, G. J. Wozniak, L. G. Moretto, D. R. Bowman, M. Chartiet, C. K. Gelbke, W. G. Gong, W. C. Hsi, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, C. Schwarz, R. T. De Souza, M. B. Tsang, F. Zhu Nov 1995

Evidence For The Reducibility Of Multifragment Emission To An Elementary Binary Emission In Xe-Induced Reactions, K. Tso, L. Phair, A. Colonna, W. Skulski, G. J. Wozniak, L. G. Moretto, D. R. Bowman, M. Chartiet, C. K. Gelbke, W. G. Gong, W. C. Hsi, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, C. Schwarz, R. T. De Souza, M. B. Tsang, F. Zhu

Faculty Publications

Multifragmentation for 129Xe-induced reactions on several targets (natCu, 89Y, 165Ho, 197Au) has been studied at . The probability of emitting n intermediate mass fragments is shown to be binomial at each transversal energy and reducible to an elementary binary probability p. For each target and at each bombarding energy, p shows a thermal behavior as demonstrated by linear Arrhenius plots. A nearly universal linear Arrhenius plot is observed at each bombarding energy, independent of target. The sensitivity of p to the Zthreshold points to its physical significance and rules out auto-correlation effects.


53. Takeo Saegusa, Otto Vogl Nov 1995

53. Takeo Saegusa, Otto Vogl

Emeritus Faculty Author Gallery

No abstract provided.


A Magnetic, Neutron-Diffraction, And Mössbauer Spectral Study Of The Ce₂Fe₁₇₋ₓsiₓ Solid Solutions, D. P. Middleton, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean, K. H. J. Buschow Nov 1995

A Magnetic, Neutron-Diffraction, And Mössbauer Spectral Study Of The Ce₂Fe₁₇₋ₓsiₓ Solid Solutions, D. P. Middleton, Sanjay R. Mishra, Gary J. Long, Oran Allan Pringle, Zhongbo Hu, William B. Yelon, Fernande Grandjean, K. H. J. Buschow

Chemistry Faculty Research & Creative Works

The magnetic properties of a series of Ce2Fe17-xSix solid solutions with x equal to 0.0, 0.23, 0.4, 0.6, 0.8, 1.02, 1.98, and 3.20 have been studied by magnetic measurements, neutron diffraction, and Mössbauer spectroscopy. An x-ray-diffraction study indicates that the compounds adopt the rhombohedral Th2Zn 17-type structure. The substitution of silicon for iron in Ce 2Fe17 leads to a contraction of the a axis by 0.2%, an expansion of the c axis by 0.2%, and a consequent reduction of the unit-cell volume by about 0.2% per substituted silicon. Magnetization studies …


Understanding Proton Emission In Central Heavy-Ion Collisions, D. O. Handzy, W. Bauer, F. C. Daffin, S. J. Gaff, C. K. Gelbke, T. Glasmacher, E. Gualtieri, S. Hannuschke, M. J. Huang, G. J. Kunde, R. Lacey, T. Li, M. A. Lisa, W. J. Llope, W. G. Lynch, L. Martin, C. P. Montoya, R. Pak, Graham F. Peaslee, S. Pratt, C. Schwarz, N. Stone, M. B. Tsang, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello Oct 1995

Understanding Proton Emission In Central Heavy-Ion Collisions, D. O. Handzy, W. Bauer, F. C. Daffin, S. J. Gaff, C. K. Gelbke, T. Glasmacher, E. Gualtieri, S. Hannuschke, M. J. Huang, G. J. Kunde, R. Lacey, T. Li, M. A. Lisa, W. J. Llope, W. G. Lynch, L. Martin, C. P. Montoya, R. Pak, Graham F. Peaslee, S. Pratt, C. Schwarz, N. Stone, M. B. Tsang, A. M. Vander Molen, G. D. Westfall, J. Yee, S. J. Yennello

Faculty Publications

Two-proton correlation functions for central collisions of 36Ar+45Sc at E/A=80, 120, and 160 MeV are compared to calculations with the Boltzmann-Uehling-Uhlenbeck (BUU) transport model. Agreement is found at E/A=80MeV, but the model predicts too large correlations at E/A=120 and 160 MeV. The discrepancy may be due to delayed emission of protons from particle-unstable states not modeled in BUU.


54. Burkart Philipp, Otto Vogl, Ch. Wandrey Oct 1995

54. Burkart Philipp, Otto Vogl, Ch. Wandrey

Emeritus Faculty Author Gallery

No abstract provided.


Tunable Picosecond Infrared Laser System Based On Parametric Amplification In Ktp With A Ti:Sapphire Amplifier, D. E. Gragson, D. S. Alavi, G. L. Richmond Oct 1995

Tunable Picosecond Infrared Laser System Based On Parametric Amplification In Ktp With A Ti:Sapphire Amplifier, D. E. Gragson, D. S. Alavi, G. L. Richmond

Chemistry and Biochemistry

A picosecond laser system that will generate high-power tunable IR pulses with bandwidths suitable for spectroscopic applications is discussed. The system is based on white-light continuum generation in ethylene glycol and optical parametric amplification in potassium titanyl phosphate. The nonlinear-optical processes are driven by a regeneratively amplified Ti:sapphire laser that produces 1.7-ps pulses at a repetition rate of 1 kHz. Energies as high as 40 and 12 µJ have been achieved over the signal (1.02–1.16-µm) and idler (2.6–3.7-µm) tuning ranges, respectively. The IR beam temporal and spatial characteristics are also presented.


Reply To ‘‘Comment On ‘Brillouin-Scattering Study Of The Elastic Constants Of Phenothiazine Through The Phase Transition’ ’’, J. Sartwell, Craig J. Eckhardt Oct 1995

Reply To ‘‘Comment On ‘Brillouin-Scattering Study Of The Elastic Constants Of Phenothiazine Through The Phase Transition’ ’’, J. Sartwell, Craig J. Eckhardt

Craig J. Eckhardt Publications

Disagreement in the ordering of relative magnitudes of the elastic constants of phenothiazine with those of Ecolivet et al. is resolved. Dubious methodologies and assumptions employed by Ecolivet et al. in their measurements, approximations, and arguments [C. Ecolivet et al., Phys. Rev. B 44, 4185 (1991)] are noted. Samples employed by these investigators in both their ultrasonic and Brillouin measurements are shown to exhibit properties consistent with impure samples and inconsistent with those of Sartwell and Eckhardt.


Structure Factors Of Binary Fluids In A Dilute Gel, J.C. Lee Oct 1995

Structure Factors Of Binary Fluids In A Dilute Gel, J.C. Lee

Faculty Publications

The statio and dynamic structure factors of binary fluids in a dilute gel are computed using a two-dimensional kinetic Ising model. The wetting effect of the gel strands is modeled with ''gel atoms'' which are distributed randomly among the spins and impose a field on their neighboring spins, all in the same direction. The result for the static structure factor shows the presence of adsorption clusters which mask the gel atoms. The result for the dynamic Structure factor shows an extremely slow relaxation-at late times which cannot be fitted in the form of the activated dynamic scaling known for random-field …


Three-Phase Intersection Points In Monolayers, John P. Hagen, Harden M. Mcconnell Sep 1995

Three-Phase Intersection Points In Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Some phospholipid/dihydrocholesterol Langmuir monolayers form coexisting liquid phases. Gas domains form at the interface between the phospholipid-rich and dihydrocholesterol-rich liquid phases when these monolayers undergo expansion to low surface pressure. Analysis of the domain shapes thus formed yields the relative line tensions of the gas/phospholipid, gas/dihydrocholesterol, and phospholipid/dihydrocholesterol phase interfaces.


55. Hermann Janeschitz-Kriegl, Otto Vogl, Anton Schausberger Sep 1995

55. Hermann Janeschitz-Kriegl, Otto Vogl, Anton Schausberger

Emeritus Faculty Author Gallery

No abstract provided.


Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman Sep 1995

Nutrient Limitation In A Southwestern Desert Reservoir: Eutrophication Of Las Vegas Bay, Lake Mead, Nevada, Davine M. Lieberman

Publications (WR)

Algal bioassay tests were conducted with Selenastrum capricornutum and natural algae on inner Las Vegas Bay, Lake Mead, Nevada, from December 1992 through September 1993, to identify any nutrient limitation in an area of the reservoir that has experienced problems associated with severe nutrient enrichment. Three areas were sampled based on a gradient of water quality conditions that existed in Las Vegas Bay (LVB). Disodium ethylenedinitrilotetraacetate (EDTA) significantly stimulated algal growth compared to non-EDTA treatment. Algal bioassays indicated that phosphorus (P) was the primary limiting nutrient at all stations for most of the test dates. Chl a response with EDTA …


Anisotropic Anharmonicity Of Lattice And Molecular Vibrations Of 1,2,4,5 Tetrabromobenzene Determined By Piezomodulated Raman Spectroscopy, K.M. White, Craig J. Eckhardt Sep 1995

Anisotropic Anharmonicity Of Lattice And Molecular Vibrations Of 1,2,4,5 Tetrabromobenzene Determined By Piezomodulated Raman Spectroscopy, K.M. White, Craig J. Eckhardt

Craig J. Eckhardt Publications

Strain-induced coupling constants for the anharmonicity of Raman-active lattice and certain molecular modes of vibration in 1,2,4,5-tetrabromobenzene (TBB) crystals have been determined using piezomodulated Raman spectroscopy. These constants, which are directly related to the first anharmonic term in the potential energy expansion for lattice dynamical calculations, are a quantitative measurement of the modal anharmonicities in the TBB molecular crystal. Application of uniaxial stress in the experiments permits the anisotropy of the anharmonicity to be determined as well as its magnitude. The TBB lattice modes are significantly coupled by the induced strains and the effects of coupling were observed to be …


Detection Of Alzheimer's Disease And Other Diseases Using An Improved Photoaffinity Labeling Method, Boyd E. Haley Aug 1995

Detection Of Alzheimer's Disease And Other Diseases Using An Improved Photoaffinity Labeling Method, Boyd E. Haley

Chemistry Faculty Patents

An improved method for diagnosing a disease comprising detecting a disease-specific biochemical marker macromolecule within a sample of extracted cerebral spinal fluid or serum is disclosed. In particular, a radioactively labeled photoaffinity probe is used to diagnose a disease. For instance, Alzheimer's disease can be diagnosed by detecting a disease-specific protein having a molecular weight of about 42,000 daltons, i.e., glutamine synthetase. Also included is a method for detecting other disease states, such as cancer, by detecting the presence or absence of specific nucleotide binding proteins.


Assessing The Evolutionary Nature Of Multifragment Decay, E. Cornell, T. M. Hamilton, D. Fox, Y. Lou, R. T. De Souza, M. J. Huang, W. C. Hsi, C. Schwarz, C. Williams, D. R. Bowman, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, L. Phair, M. B. Tsang, G. Vanburen, R. J. Charity, L. G. Sobotka, W. A. Friedman Aug 1995

Assessing The Evolutionary Nature Of Multifragment Decay, E. Cornell, T. M. Hamilton, D. Fox, Y. Lou, R. T. De Souza, M. J. Huang, W. C. Hsi, C. Schwarz, C. Williams, D. R. Bowman, J. Dinius, C. K. Gelbke, T. Glasmacher, D. O. Handzy, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, L. Phair, M. B. Tsang, G. Vanburen, R. J. Charity, L. G. Sobotka, W. A. Friedman

Faculty Publications

Multifragment decays of central collisions in 84Kr+197Au at E/A=35, 55, and 70 MeV are studied. The dependence of the extracted emission time on the velocity of the fragment pair is investigated. More energetic pairs manifest a stronger Coulomb interaction, indicating emission from a source of smaller spatial-temporal extent than less energetic pairs. This trend can be understood in the context of a statistical model that allows the source characteristics to evolve as the fragments are emitted.


Ultrastructural Immunolocalization Of Histones (H2b, H3, H4), Transition Protein (Tp1) And Protamine In Rabbit Spermatids And Spermatozoa Nuclei. Relation To Condensation Of The Chromatin, J L. Courtens, Wilson Stephen Kistler, L Plöen Aug 1995

Ultrastructural Immunolocalization Of Histones (H2b, H3, H4), Transition Protein (Tp1) And Protamine In Rabbit Spermatids And Spermatozoa Nuclei. Relation To Condensation Of The Chromatin, J L. Courtens, Wilson Stephen Kistler, L Plöen

Faculty Publications

The histones H2B, H3 and H4, the transition protein TP1 and protamine were localised using ultrastructural immunocytochemistry in nuclei of rabbit spermatids and spermatozoa. Histones are present in round spermatid nuclei and are lost during the elongation of nuclei. TP1 and protamine appear simultaneously in all nuclei during this period. TP1 is located at the periphery of chromatin cords, while protamine seems to be located at random in the same cords. TP1 is lost in most elongated sprematids during step 13 of spermiogenesis, and the protamine stays in all sperm nuclei. TP1 remains persent in some old spermatids and ejaculated …


56. Sir Geoffrey Allan, Otto Vogl, Shigeko Suzuki Aug 1995

56. Sir Geoffrey Allan, Otto Vogl, Shigeko Suzuki

Emeritus Faculty Author Gallery

No abstract provided.


Space-Time Characteristics Of Fragment Emission In The E/A=30 Mev 129xe + Natcu Reaction, D. R. Bowman, N. Colonna, W. A. Friedman, L. Celano, M. D'Agostino, J. D. Dinius, A. Ferrero, C. K. Gelbke, T. Glasmacher, D. O. Handzy, D. Horn, W. C. Hsi, M. Huang, I. Iori, M. A. Lisa, W. G. Lynch, G. V. Margagliotti, P. M. Milazzo, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, F. Petruzzelli, R. Scardaoni, C. Schwarz, M. B. Tsang, C. Williams Aug 1995

Space-Time Characteristics Of Fragment Emission In The E/A=30 Mev 129xe + Natcu Reaction, D. R. Bowman, N. Colonna, W. A. Friedman, L. Celano, M. D'Agostino, J. D. Dinius, A. Ferrero, C. K. Gelbke, T. Glasmacher, D. O. Handzy, D. Horn, W. C. Hsi, M. Huang, I. Iori, M. A. Lisa, W. G. Lynch, G. V. Margagliotti, P. M. Milazzo, C. P. Montoya, A. Moroni, Graham F. Peaslee, L. Phair, F. Petruzzelli, R. Scardaoni, C. Schwarz, M. B. Tsang, C. Williams

Faculty Publications

Intermediate-mass-fragment emission has been studied in central E/A=30 MeV Xe129+natCu reactions. The measured fragment multiplicities, reduced-velocity correlation functions, and emission velocities have been compared with schematic three-body trajectory calculations and with three statistical models with input based upon a dynamical BNV code. The statistical models which include expansion either explicitly or implicitly are able to generate a sufficient number of fragments. The three-body trajectory calculations indicate a mean emission time of ≊200 fm/c, consistent with sequential decay. Dynamical expanding-emitting source calculations predict a similar time scale for fragment emission and give satisfactory agreement with the experimental correlation functions if the …


Reducibility And Thermal Scaling Of Charge Distributions In Multifragmentation, L. Phair, K. Tso, R. Ghetti, G. J. Wozniak, L. G. Moretto, R. T. De Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu Jul 1995

Reducibility And Thermal Scaling Of Charge Distributions In Multifragmentation, L. Phair, K. Tso, R. Ghetti, G. J. Wozniak, L. G. Moretto, R. T. De Souza, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

A strong thermal signature is found in the charge distributions associated with multifragmentation from the reaction 36Ar+197Au at E/A=110 MeV. The n-fold charge distributions are reducible to the onefold charge distributions through a simple scaling that is dictated by fold number and charge conservation.


57. Peter Plesch, Otto Vogl, Traudl Plesch Jul 1995

57. Peter Plesch, Otto Vogl, Traudl Plesch

Emeritus Faculty Author Gallery

No abstract provided.


Angle-Resolved Photoelectron Spectroscopy Of C60, T. Liebsch, O. Plotzke, Franz Heiser, U. Hergenhahn, Oliver Hemmers, R. Wehlitz, J. Viefhaus, B. Langer, S. B. Whitfield, U. Becker Jul 1995

Angle-Resolved Photoelectron Spectroscopy Of C60, T. Liebsch, O. Plotzke, Franz Heiser, U. Hergenhahn, Oliver Hemmers, R. Wehlitz, J. Viefhaus, B. Langer, S. B. Whitfield, U. Becker

Environmental Studies Faculty Publications

Angle-resolved photoelectron spectra of gaseous C60 were recorded in the photon energy regions from 21 to 108 eV and from 295 to 320 eV. Partial cross sections σ and the angular distribution anisotropy parameter β vary significantly with photon energy, particularly in the near-threshold region of the valence and the core ionization regimes. Some of these effects may be attributed to scattering of the outgoing photoelectron by the atoms of the ionized C60 molecule. Our results indicate that the observed satellites of the C(1s) main line are most likely of shake-up character. Low-energy electrons emitted below the shake-off …


Environments Of The Four Tryptophans In The Extracellular Domain Of Human Tissue Factor: Comparison Of Results From Absorption And Fluorescence Difference Spectra Of Tryptophan Replacement Mutants With The Crystal Structure Of The Wild-Type Protein, C. A. Hasselbacher, E. Rusinova, R. Rusinova, R. A. Kohanski, W. Lam, A. Guha, J. Du, T. C. Lin, I. Polikarpov, C. W. G. Boys, Y. Nemerson, W. H. Konigsberg, J. B. A. Ross Jul 1995

Environments Of The Four Tryptophans In The Extracellular Domain Of Human Tissue Factor: Comparison Of Results From Absorption And Fluorescence Difference Spectra Of Tryptophan Replacement Mutants With The Crystal Structure Of The Wild-Type Protein, C. A. Hasselbacher, E. Rusinova, R. Rusinova, R. A. Kohanski, W. Lam, A. Guha, J. Du, T. C. Lin, I. Polikarpov, C. W. G. Boys, Y. Nemerson, W. H. Konigsberg, J. B. A. Ross

Chemistry and Biochemistry Faculty Publications

The local environments of the four tryptophan residues of the extracellular domain of human tissue factor (sTF) were assessed from difference absorption and fluorescence spectra. The difference spectra were derived by subtracting spectra from single Trp-to-Phe or Trp-to-Tyr replacement mutants from the corresponding spectrum of the wild-type protein. Each of the mutants was capable of enhancing the proteolytic activity of factor Vila showing that the mutations did not introduce major structural changes, although the mutants were more susceptible to denaturation by guanidinium chloride. The difference spectra indicate that the Trp residues are buried to different extents within the protein matrix. …


Relative Stabilities Of Dna 3-Way, 4-Way And 5-Way Junctions (Multi-Helix Junction Loops) - Unpaired Nucleotides Can Be Stabilizing Or Destabilizing, Neocles B. Leontis, Julie L. Kardmas, Amy J. Ravin Jun 1995

Relative Stabilities Of Dna 3-Way, 4-Way And 5-Way Junctions (Multi-Helix Junction Loops) - Unpaired Nucleotides Can Be Stabilizing Or Destabilizing, Neocles B. Leontis, Julie L. Kardmas, Amy J. Ravin

Chemistry Faculty Publications

Competition binding and UV melting studies of a DNA model system consisting of three, four or five mutually complementary oligonucleotides demonstrate that unpaired bases at the branch point stabilize three- and five-way junction loops but destabilize four-way junctions. The inclusion of unpaired nucleotides permits the assembly of five-way DNA junction complexes (5WJ) having as few as seven basepairs per arm from five mutually complementary oligonucleotides. Previous work showed that 5WJ, having eight basepairs per arm but lacking unpaired bases, could not be assembled I[Wang,Y.L., Mueller,J.E., Kemper,B. and Seeman,N.C. (1991) Biochemistry, 30, 5667-5674]. Competition binding experiments demonstrate that four-way junctions (4WJ) …