90 research outputs found
On the non-relativistic limit of the quantum sine-Gordon model with integrable boundary condition
We show that the the generalized Calogero-Moser model with boundary potential
of the P\"oschl-Teller type describes the non-relativistic limit of the quantum
sine-Gordon model on a half-line with Dirichlet boundary condition.Comment: 6 pages, CALT-68-1949, USC-94-01
First order quantum corrections to the classical reflection factor of the sinh-Gordon model
The sinh-Gordon model is restricted to a half-line by boundary conditions
maintaining integrability. A perturbative calculation of the reflection factor
is given to one loop order in the bulk coupling and to first order in the
difference of the two parameters introduced at the boundary, providing a
further verification of Ghoshal's formula. The calculation is consistent with a
conjecture for the general dependence of the reflection factor on the boundary
parameters and the bulk coupling.Comment: 16 pages, 1 figur
Meromorphic Solutions to a Differential--Difference Equation Describing Certain Self-Similar Potentials
In this paper we prove the existence of meromorphic solutions to a nonlinear
differential difference equation that describe certain self-similar potentials
for the Schroedinger operator.Comment: 10 pages, LaTeX, uses additional package
The boundary sine-Gordon theory: classical and semi-classical analysis
We consider the sine-Gordon model on a half-line, with an additional
potential term of the form at the
boundary. We compute the classical time delay for general values of ,
and using -function methods and show that in the
classical limit, the method of images still works, despite the non-linearity of
the problem. We also perform a semi-classical analysis, and find agreement with
the exact quantum S-matrix conjectured by Ghoshal and Zamolodchikov.Comment: 19 pages, 5 figures. Preprint USC-94-013. (Numerical mistake
corrected.
Surface excitations and surface energy of the antiferromagnetic XXZ chain by the Bethe ansatz approach
We study boundary bound states using the Bethe ansatz formalism for the open XXZ (Δ > 1) chain in a boundary magnetic field h. Boundary bound states are represented by the 'boundary strings' similar to those described in Skorik and Saleur. We find that for certain values of h the ground-state wavefunction contains boundary strings and from this infer the existence of two 'critical' fields in agreement with Jimbo et al. An expression for the vacuum surface energy in the thermodynamic limit is derived and found to be an analytic function of h. We argue that boundary excitations appear only in pairs with `bulk' excitations or with boundary excitations at the other end of the chain. We mainly discuss the case where the magnetic fields at the left and the right boundaries are antiparallel, but we also comment on the case of parallel fields. In the Ising (Δ = ∞) and isotropic (Δ = 0) limits our results agree with those previously known
Physicochemical and adsorption properties of some carbon materials in aqueous solutions
Water dispersions of carbon adsorbents-nanodiamonds of UD-DP and UD-HP-DP types, nanodiamond charge of UDB-A type, C-60 fullerene, nanotubes, and activated carbon-were studied. Some physicochemical properties of their surface (acidity and electrokinetic characteristics) were investigated, and the surface values of pK(a1) were calculated. The data on adsorption of iodine, malic acid, and cationic dyes onto these adsorbents from aqueous and 1 mol/L NaCl solutions were discussed and compared. The dyeadsorption data and the values of the zeta potential and suspension effect indicated a negatively charged surface of UDA-SP nanodiamond within a pH adsorption range from 5.5 to 8.0
Boundary bound states and boundary bootstrap in the sine-Gordon model with Dirichlet boundary conditions.
We present a complete study of boundary bound states and related boundary
S-matrices for the sine-Gordon model with Dirichlet boundary conditions. Our
approach is based partly on the bootstrap procedure, and partly on the explicit
solution of the inhomogeneous XXZ model with boundary magnetic field and of the
boundary Thirring model. We identify boundary bound states with new ``boundary
strings'' in the Bethe ansatz. The boundary energy is also computed.Comment: 25 pages, harvmac macros Report USC-95-001
Effect of Double Substitution in Cationic Chitosan Derivatives on DNA Transfection Efficiency
Recently, much effort has been expended on the development of non-viral gene delivery systems based on polyplexes of nucleic acids with various cationic polymers. Natural polysaccharide derivatives are promising carriers due to their low toxicity. In this work, chitosan was chemically modified by a reaction with 4-formyl-n,n,n-trimethylanilinium iodide and pyridoxal hydrochloride and subsequent reduction of the imine bond with NaBH4. This reaction yielded three novel derivatives, n-[4-(n',n',n'-trimethylammonium)benzyl]chitosan chloride (TMAB-CS), n-[(3-hydroxy-5-(hydroxymethyl)-2-methyl-4-pyridine)methyl]chitosan chloride (Pyr-CS), and n-[4-(n',n',n''-trimethylammonium)benzyl]-n-[(3-hydroxy-5-(hydroxymethyl)-2-methyl-4-pyridine)methyl]chitosan chloride (PyrTMAB-CS). Their structures and degrees of substitution were established by H-1 NMR spectroscopy as DS1 = 0.22 for TMAB-CS, DS2 = 0.28 for Pyr-CS, and DS1 = 0.21, DS2 = 0.22 for PyrTMAB-CS. Dynamic light scattering measurements revealed that the new polymers formed stable polyplexes with plasmid DNA encoding the green fluorescent protein (pEGFP-N3) and that the particles had the smallest size (110-165 nm) when the polymer:DNA mass ratio was higher than 5:1. Transfection experiments carried out in the HEK293 cell line using the polymer:DNA polyplexes demonstrated that Pyr-CS was a rather poor transfection agent at polymer:DNA mass ratios less than 10:1, but it was still more effective than the TMAB-CS and PyrTMAB-CS derivatives that contained a quaternary ammonium group. By contrast, TMAB-CS and PyrTMAB-CS were substantially more effective than Pyr-CS at higher polymer:DNA mass ratios and showed a maximum efficiency at 200:1 (50%-70% transfected cells). Overall, the results show the possibility of combining substituent effects in a single carrier, thereby increasing its efficacy.Peer reviewe
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