Use of a lambda gt11 expression library to localize a neutralizing antibody-binding site in glycoprotein E2 of Sindbis virus

The Sindbis virus envelope contains two species of integral membrane glycoproteins, E1 and E2. These proteins form heterodimers, and three dimeric units assemble to form spikes incorporated into the viral surface which play an important role in the specific attachment of Sindbis virus to host cells. To map the neutralization epitopes on the surface of the virus, we constructed a lambda gt11 expression library with cDNA inserts 100 to 300 nucleotides long obtained from randomly primed synthesis on Sindbis virus genomic RNA. This library was screened with five different neutralizing monoclonal antibodies (MAbs) specific for E2 (MAbs 50, 51, 49, 18, and 23) and with one neutralizing MAb specific for E1 (MAb 33). When 10(6) lambda gt11 plaques were screened with each antibody, four positive clones that reacted with E2-specific MAb 23 were found. These four clones contained overlapping inserts from glycoprotein E2; the domain from residues 173 to 220 of glycoprotein E2 was present in all inserts, and we concluded that this region contains the neutralization epitope recognized by the antibody. No clones that reacted with the other antibodies examined were found, and we concluded that these antibodies probably recognize conformational epitopes not present in the lambda gt11 library. We suggest that the E2 domain from residues 173 to 220 is a major antigenic determinant of Sindbis virus and that this domain is important for virus attachment to cells

Replica Monte Carlo Simulation (Revisited)

In 1986, Swendsen and Wang proposed a replica Monte Carlo algorithm for spin glasses [Phys. Rev. Lett. 57 (1986) 2607]. Two important ingredients are present, (1) the use of a collection of systems (replicas) at different of temperatures, but with the same random couplings, (2) defining and flipping clusters. Exchange of information between the systems is facilitated by fixing the tau spin (tau=sigma^1\sigma^2) and flipping the two neighboring systems simultaneously. In this talk, we discuss this algorithm and its relationship to replica exchange (also known as parallel tempering) and Houdayer's cluster algorithm for spin glasses. We review some of the early results obtained using this algorithm. We also present new results for the correlation times of replica Monte Carlo dynamics in two and three dimensions and compare them with replica exchange.Comment: For "Statistical Physics of Disordered Systems and Its Applications", 12-15 July 2004, Shonan Village Center, Hayama, Japan, 7 page

Plancherel-Rotach asymptotic expansion for some polynomials from indeterminate moment problems

We study the Plancherel--Rotach asymptotics of four families of orthogonal polynomials, the Chen--Ismail polynomials, the Berg-Letessier-Valent polynomials, the Conrad--Flajolet polynomials I and II. All these polynomials arise in indeterminate moment problems and three of them are birth and death process polynomials with cubic or quartic rates. We employ a difference equation asymptotic technique due to Z. Wang and R. Wong. Our analysis leads to a conjecture about large degree behavior of polynomials orthogonal with respect to solutions of indeterminate moment problems.Comment: 34 pages, typos corrected and references update

Phonon Hall Effect in Four-Terminal Junctions

Using an exact nonequilibrium Green's function formulism, the phonon Hall effect for paramagnetic dielectrics is studied in a four-terminal device setting. The temperature difference in the transverse direction of the heat current is calculated for two-dimensional models with the magnetic field perpendicular to the plane. We find a surprising result that the square lattice does not have the phonon Hall effect while a honeycomb lattice has. This can be explained by symmetry. The temperature difference changes sign if the magnetic field is sufficiently large.Comment: 4 pages, 5 figure