Yang-Mills cosmologies and collapsing gravitational sphalerons

Cosmological solutions with a homogeneous Yang-Mills field which oscillates and passes between topologically distinct vacua are discussed. These solutions are used to model the collapsing Bartnik-McKinnon gravitational sphaleron and the associated anomalous production of fermions. The Dirac equation is analyzed in these backgrounds. It is shown explicity that a fermion energy level crosses from the negative to positive energy spectrum as the gauge field evolves between the topologically distinct vacua. The cosmological solutions are also generalized to include an axion field.     

4-Dimensional black holes from Kaluza-Klein theories

In this paper we consider generalizations in 4 dimensions of the Einstein-Maxwell equations which typically arise from Kaluza-Klein theories. We specify conditions such that stationary solutions lead to non-linear-models for symmetric spaces. Using both this group theoretic structure and some properties of harmonic maps we are able to generalize many of the known existence and uniqueness theorems for black holes in Einstein-Maxwell theory to this more general setting.     

Determination of 6-N-trimethyllysine in urine by high-performance liquid chromatography

A method for determination of 6-N-trimethyllysine in urine is described. Trimethyllysine and the chemically analogous 6-N-triethyllysine internal standard were isolated from aqueous samples by microcolumn ion-exclusion chromatography. The specimens were derivatized by reaction with 1-fluoro-2,4-dinitrobenzene and reaction byproducts extracted by organic solvents. The trimethyllysine and internal standard derivatives were separated easily from other sample constituents by reversed-phase paired-ion high-performance liquid chromatography with spectrophotometric detection at 405 nm. Standard curves were linear over a sample concentration range of 10-150 nmol/ml; the detection limit corresponded with 0.1 nmol trimethyllysine injected into the chromatograph. The procedure was used for determination of trimethyllysine in human urine.     

Dissociation constants of the ampholyte glycine in 50 mass % methanol-water from 5 to 55°C,with related thermodynamic quantities

The two thermodynamic dissociation constants of glycine at 11 temperatures from 5 to 55°C in 50 mass % methanol-water mixed solvent have been determined from precise emf measurements with hydrogen-silver bromide electrodes in cells without liquid junction. The first acidic dissociation constant (K ₁)for the process HG⁺H⁺+G^± is expressed as a function ofT(^oK) by the equation pK ₁ = 2043.5/T – 9.6504 + 0.019308T. At 25°C, pK ₁is 2.961 in the mixed solvent, as compared with 2.350 in water, with H°=1497 cal-mole^–1, G°=4038 cal-mole^–1, S°=–8.52 cal-°K^–1-mole^–1, and C _p ^o =–53 cal-°K^–1-mole^–1. The second acidic dissociation constant (K ₂)for the process G^±H⁺+G^– over the temperature range studied is given by the equation pK ₂ = 3627.1/T – 7.2371 + 0.015587T. At 25°C, pK ₂is 9.578 in MeOH–H₂O as compared with 9.780 in water, whereas H° is 10,257 cal-mole^–1, G° is 13,063 cal-mole^–1, S° is –9.41 cal-°K^–1-mole^–1, and C _p ^o is –43 cal-°K^–1-mole^–1. The protonated glycine becomes weaker in 50 mass % methanol-water, whereas the second dissociation process becomes stronger despite the lower dielectric constant of the mixed solvent (=56.3 at 25°C).     

Cadmium selenide quantum wires and the transition from 3D to 2D confinement

Soluble CdSe quantum wires are prepared by the solution-liquid-solid mechanism, using monodisperse bismith nanoparticles to catalyze wire growth. The quantum wires have micrometer lengths, diameters in the range of 5-20 nm, and diameter distributions of +/-10-20%. Spectroscopically determined wire band gaps compare closely to those calculated by the semiemipirical pseudopotential method, confirming 2D quantum confinement. The diameter dependence of the quantum wire band gaps is compared to that of CdSe quantum dots and rods. Quantum rod band gaps are shown to be delimited by the band gaps of dots and wires of like diameter, for short and long rods, respectively. The experimental data suggest that a length of ca. 30 nm is required for the third dimension of quantum confinement to fully vanish in CdSe rods. That length is about six times the bulk CdSe exciton Bohr radius.     

Spacetime Interpretation of Torsion in Prismatic Bodies

A non-linear theory for the plastic deformation of prismatic bodies is constructed which interpolates between Prandtl??s linear soap-film approximation and Nádai??s sand-pile model. Geometrically Prandtl??s soap film and Nádai??s wavefront are unified into a single smooth surface of constant mean curvature in three-dimensional Minkowski spacetime.