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Α-Vinyllysine And Α-Vinylarginine Are Time-Dependent Inhibitors Of Their Cognate Decarboxylases, David B. Berkowitz, Wan Jin Jahng, Michelle L. Pedersen
Α-Vinyllysine And Α-Vinylarginine Are Time-Dependent Inhibitors Of Their Cognate Decarboxylases, David B. Berkowitz, Wan Jin Jahng, Michelle L. Pedersen
Chemistry Department: Faculty Publications
(±)-α-Vinyllysine and (±)-α-vinylarginine display time-dependent inhibition of L-lysine decarboxylase from B. cadaveris, and L-arginine decarboxylase from E. coli, respectively. A complete Kitz-Wilson analysis has been performed using a modification of the Palcic continuous UV assay for decarboxylase activity.
Model Calculations Of Langmuir Monolayers: Pressure Effects On Tilting Behavior Of Idealized Amphiphiles, D.R. Swanson, Robert J. Hardy, Craig J. Eckhardt
Model Calculations Of Langmuir Monolayers: Pressure Effects On Tilting Behavior Of Idealized Amphiphiles, D.R. Swanson, Robert J. Hardy, Craig J. Eckhardt
Craig J. Eckhardt Publications
Model amphiphiles consisting of lines of Lennard-Jones (LJ) centers are investigated to determine the effect of pressure and molecular geometry on ground-state tilting behavior. Both the amphiphile length and the intramolecular distance between LJ centers is varied. The results give guidelines for understanding and controlling tilting behavior in monolayer films.
Synthesis Of Higher Α-Chlorovinyl And Α-Bromovinyl Amino Acids: The Amino Protecting Group Determines The Reaction Course, David B. Berkowitz, Michelle L. Pedersen, Wan Jin Jahng
Synthesis Of Higher Α-Chlorovinyl And Α-Bromovinyl Amino Acids: The Amino Protecting Group Determines The Reaction Course, David B. Berkowitz, Michelle L. Pedersen, Wan Jin Jahng
Chemistry Department: Faculty Publications
N-Trifluoroacetyl α-vinyl amino esters are smoothly converted to the corresponding α-chlorovinyl or α-bromovinyl amino esters through the agency of phenyselenyl chloride or phenylselenyl bromide, respectively, followed by oxidation and pyrolysis. Exclusively the (E)-extemal halovinyl isomer and the internal halovinyl isomer are observed. The amino protecting group is a critical determinant of the reaction course (alkene addition vs. 5-exo-trig-like cyclization).
Epitaxial Growth Of Co3O3 On Coo(100), G.A. Carson, M.H. Nassir, Marjorie Langell
Epitaxial Growth Of Co3O3 On Coo(100), G.A. Carson, M.H. Nassir, Marjorie Langell
Marjorie A. Langell Publications
Under mildly oxidizing ultrahigh vacuum conditions, it is possible to form on top of CoO(100) single crystal substrates, thin films that have higher oxygen content but that preserve the overall symmetry of the CoO(100) low-energy electron diffraction pattern. X-ray photoelectron spectroscopy (XPS) and high-resolution electron-energy-loss spectroscopy (HREELS) data indicate that the epitaxial film grown on CoO(100) at 625 K and 531027 Torr is Co3O3-like in both oxygen content and XP/HREEL spectroscopic characteristics. Both materials are closest packed in lattice oxygen, with the mismatch of bulk O2-–O2- distances of approximately 5%. However, the Co …
High Resolution Electron Energy Loss Spectroscopy Of Mno(100) And Oxidized Mno(100), Marjorie Langell, C.W. Hutchings, G.A. Carson , M.H. Nassir
High Resolution Electron Energy Loss Spectroscopy Of Mno(100) And Oxidized Mno(100), Marjorie Langell, C.W. Hutchings, G.A. Carson , M.H. Nassir
Marjorie A. Langell Publications
Single crystal MnO(100) substrates can be selectively oxidized to produce Mn2O3- and Mn3O4-like surfaces under mild oxidation/reduction conditions readily accessed under ultrahigh vacuum (UHV). MnO(100) yields a characteristic Mn 2p x-ray photoelectron spectroscopy (XPS) satellite structure and appropriate O/Mn concentrations from O 1s/Mn 2p XPS intensity ratios. Its high resolution electron energy loss (HREEL) spectrum shows a series of Fuchs–Kliewer multiple phonon excitations with a single loss energy of 70.9 meV, characteristic of the cubic manganese monoxide structure. However, the HREEL spectral (HREELS) background is high and the …
Thermal Nucleation And Cavitation In Helium-3 Fluids, Xiao Cheng Zeng, D.W. Oxtoby, E. Cheng
Thermal Nucleation And Cavitation In Helium-3 Fluids, Xiao Cheng Zeng, D.W. Oxtoby, E. Cheng
Xiao Cheng Zeng Publications
We have investigated droplet nucleation and bubble cavitation in the quantum fluid helium-3 based on a nonlocal density-functional approach. A marked effect of droplet (or bubble) curvature on the rate of droplet nucleation or cavitation has been found. Without considering this curvature effect (as in the classical theory of nucleation) the droplet nucleation rate for helium-3 could be underestimated (i.e., near 1 K) or overestimated (i.e., near 2.5 K) by orders of magnitude, respectively; for bubble cavitation, the rate could be underestimated by more than twenty orders of magnitude (near 1 K).
Gas–Liquid Nucleation In Two-Dimensional Fluids, Xiao Cheng Zeng
Gas–Liquid Nucleation In Two-Dimensional Fluids, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
A nonclassical theory of nucleation, based on the density-functional (DF) approach, is developed for the gas–liquid transitions of two-dimensional (2D) Lennard-Jones (LJ) fluids. The methods of Weeks–Chandler–Andersen perturbation theory are used to approximate the LJ potential with a temperature-dependent hard-disk diameter plus an attractive tail. The resulting free energy functional is then used to calculate the free energy barrier to nucleation. We find that the curvature of the 2D nucleus is not important to the rate of nucleation (in contrast to the 3D counterpart). The effect of curvature is readily inferred from the ratio of nucleation rate from classical Becker–Dö̈ring …
Highly Reactive Form Of Copper And Reagents Thereof, Reuben D. Rieke
Highly Reactive Form Of Copper And Reagents Thereof, Reuben D. Rieke
Chemistry Department: Faculty Publications
A novel Zerovalent copper species and an organocopper reagent are disclosed. The Zerovalent copper species is directly produced by reaction of a reducing agent with a combination of copper(I) cyanide or halide and an alkali metal halide salt. The organocopper reagent resulting from the reaction of the zerovalent copper species and an organic compound having one or more stable anionic leaving groups is a stable reagent that will not significantly homocouple and under controlled conditions tolerates the presence of nitrile, epoxide, imine, enone, ketone, ester, allyl and benzyl groups within the organo radical. The reagent can be controlled so that …
A Convenient Synthesis Of L-Α-Vinylglycine From L-Homoserine Lactone, David B. Berkowitz, Marianne K. Smith
A Convenient Synthesis Of L-Α-Vinylglycine From L-Homoserine Lactone, David B. Berkowitz, Marianne K. Smith
David Berkowitz Publications
A procedure for the synthesis ofL-IX-vinylglycine from L-homoserine lactone is described. The route developed is convenient (only one chromatography step is required) and efficient (72 %; ≥ 95 % optical yield over 4 steps). Key features include the use of acid-labile protecting groups for the amino (Boc) and carboxyl (diphenylmethyl ester) groups, and the use of the phenylselenolate equivalent derived from sodium borohydride and diphenyl diselenide for L-homoserine lactone cleavage.
Highly Reactive Zerovalent Metals From Metal Cyanides, Reuben D. Rieke
Highly Reactive Zerovalent Metals From Metal Cyanides, Reuben D. Rieke
Chemistry Department: Faculty Publications
Novel zerovalent metal species and organometallic reagents are disclosed. The zerovalent metal species are directly produced by reaction of a reducing agent on a metal cyanide salt. Preferably, the zerovalent metal species are directly produced by reaction of an alkali metal reducing agent with a metal cyanide salt. The organometallic reagent results from the reaction of the zerovalent metal species and an organic compound having one or more stable anionic leaving groups.