Edible mushroom (Agaricus bisporus) lectin, which reversibly inhibits epithelial cell proliferation, blocks nuclear localization sequence-dependent nuclear protein import

The Galbeta1-3GalNAcalpha (TF antigen)-binding lectin (ABL) from the common edible mushroom (Agaricus bisporus) has a potent anti-proliferative effect without any apparent cytotoxicity. This unusual combination of properties prompted investigation of its mechanism of action. In contrast to soluble lectin, agarose-immobilized, and hence noninternalizable ABL had no effect on proliferation of HT29 colon cancer cells. Electron microscopy of HT29 cells incubated with fluorescein- and gold-conjugated ABL showed internalization of the lectin into endocytotic vesicles and multivesicular bodies. Confocal microscopy showed perinuclear accumulation of fluorescein isothiocyanate-conjugated lectin, which also inhibits HT29 cell proliferation, raising the possibility that the lectin might interfere with nuclear pore function. Transport of heat shock protein 70 into the nucleus in response to heat shock was blocked by preincubation of HT29 cells for 6 h with 40 micrograms/ml ABL. In digitonin-permeabilized cells, nuclear uptake of bovine albumin conjugated to a nuclear localization sequence (NLS)-containing peptide was also inhibited by a 15-min preincubation with 40-100 micrograms/ml ABL. In contrast, serum-stimulated nuclear translocation of mitogen-activated protein kinase, which is NLS-independent, was not affected by pretreatment of cells with the lectin. These results suggest that the anti-proliferative effect of ABL is likely to be a consequence of the lectin trafficking to the nuclear periphery, where it blocks NLS-dependent protein uptake into the nucleus.     

Shape of a particle curtain falling in stagnant air

The dynamics of a free falling particle curtain were analysed and studied in the laboratory. In the experiments a steady, uniform, high-voidage stream of particles was fed through a rectangular slit to form a curtain across the entire width of a horizontal duct of cross-section of 0.15 × 0.60 m. The thickness of the particle stream at the inlet was varied over the range 2-10 cm by varying the width of the rectangular slit. The particle flow rates were maintained constant at approximately 0.040 kg/s. The shape of the particle curtain was recorded using a high-speed video camera. Our results indicated a low voidage curtain led to diverging curtain; increasing the initial voidage of the particle stream caused the curtain to become less divergent; further increase the voidage of the particle stream caused the curtain to become increasingly convergent. The shape of particle curtain was analysed using an Eulerian-Eulerian computational fluid dynamics (CFD) model. Reasonable agreement was found between the experiments and the CFD model predictions.     

Experimental investigation of soliton optical phase jitter

The soliton optical phase stability versus amplified spontaneous noise is investigated in a recirculation loop experiment in the presence of in-line filters. The behavior of phase fluctuations is shown to be in good agreement with numerical simulations. The phase standard deviation is kept below 0.15×π for distances up to 8000 km. We, therefore, demonstrate the feasibility of phase-shift keying on solitons for long-haul transmission systems     

Evaluation of a platinum leasing program for fuel cell vehicles

This paper evaluates the feasibility of a platinum leasing program for future fuel-cell vehicles (FCVs) in the United States. By internalizing the residual value of platinum in the vehicle's upfront cost, a platinum lease may offer cost savings to the consumer. Several leasing scenarios were evaluated to estimate potential cash savings.     

Transient response of a cold atomic beam in the presence of a far-off resonance light guide

Abstract

A low velocity intense source (LVIS) of cold rubidium atoms is guided along a co-propagating far-off resonance light guide. An 8% enhancement of the guided atomic flux is observed in the steady state. Data are presented for the transient response of the LVIS to the guide beam observing a non-adiabatic kick and a transient 25% enhancement of the guided flux. A characteristic decay time of 0.45 s is recorded for the return to the steady state flux.     

Low-frequency magnetic shielding studies on high-Tc superconductor Y-Ba-Cu-O

Low frequency (10-Hz to 100-MHz) magnetic-shielding studies were performed on high-T_c superconductors Y-Ba-Cu-O to investigate the material's shielding behavior. The critical field H_c1 in the superconductor was observed to be ⩽17.8 G. The superconductor shielded down to the background noise level independent of the frequency when the applied field strength was⩽ H_c1. In the vortex state, just above H_c1, the superconductor-type transformer behaved nonlinearly. A semiempirical model for the skin depth was used to fit the nonlinear data. In the high applied field limit, this shielding data was shown to have a square-root frequency dependence similar to ordinary shielding materials. At lower fields above H_C1, data tended toward frequency independence. Noise-limited experimental low-frequency results indicated that the superconductor shielded at least as well as common state-of-the-art materials