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Weak-localization magnetoresistance has been measured as a function of carrier density using a backgate technique. The phase relaxation rate and the spin-orbit relaxation rate have been determined. The dominating contribution to the phase relaxation rate comes from electron-electron interaction, as demonstrated for samples covering densities from 2.5 to 7.5×10 15 m -2 . Interband scattering is found to enhance phase relaxation. A strictly two-dimensional electron gas (2DEG) quenches the spin-orbit relaxation rate in the plane of the 2DEG, 1/τ so xy , whereas the orthogonal part, 1/τ so z appears added to the phase relaxation rate in the interpretation of the weak-localization magnetoresistance, and can be determined as the saturation value of the phase relaxation at low temperatures

Physical review / B 62(5), 052703 (2000). doi:10.1103/PhysRevA.62.052703, Published by Inst.8644, Woodbury, NY

PURPOSE To evaluate the use of Scheimpflug photography in the examination of iris configuration and anterior chamber depth in eyes with pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG). METHODS The Nidek EAS 1000 Scheimpflug camera was used to photograph the anterior segment of 12 eyes with PDS/PG, as well as 12 age-matched controls and four eyes with primary open-angle glaucoma (POAG). Anterior chamber depth, iris insertion angle, and iris configuration were evaluated. Five eyes of three patients were serially photographed over 10 min while blinking was prevented. RESULTS Patients with PDS/PG showed deeper anterior chambers than age-matched controls or patients with POAG. Nine of 12 PDS/PG eyes showed a concave iris configuration. There were no concave irides noted in control or POAG eyes. Preventing blinking resulted in significant anterior excursion of concave irides in three of the five eyes studied. CONCLUSIONS Scheimpflug photography is a useful modality to study iris configuration. These photographs document the presence of a concave iris configuration in some patients with PDS/PG, and support the hypothesis that blinking may be significant in producing this configuration.

The binding of 13 different lectins to gp120 partially purified from two HIV-1 isolates and one HIV-2 isolate was studied by in situ staining on electrophoretically separated and electroblotted HIV antigens. The lectins concanavalin A, wheat germ agglutinin, Lens culinaris agglutinin, Vicia faba agglutinin, Pisum sativum agglutinin and phytohaem(erythro)agglutinin bound to gp120 of all three isolates. The carbohydrate of gp120 recognized by lectins was thus arranged in at least four types of glycans: a high mannose type glycan, a bisected hybrid or complex type glycan, a biantennary fucosylated complex type glycan and a triantennary bisected complex type glycan. Only lectins which bound at least one of the four types of glycans were capable of inhibiting fusion of HIV-infected cells with CD4 cells by a carbohydrate-specific interaction with the HIV-infected cells. Thus, several different glycan structures may be implicated in CD4-gp120 binding.

The incidence, histology, and proposed origin of Warthin's tumor are discussed in conjunction with an extremely rare occurrence of simultaneous bilateral tumors in a woman, the second such reported case. It is hoped that presentation of this case emphasizes the need to consider the possibility of bilateral occurrences when evaluating masses in the parotid region.