Concanavalin A-induced cap formation in rat ascites hepatoma cells (AH 7974) and the interaction of cytoplasmic proteins with plasma membranes.

Concanavalin A (Con A) induced cap formation in rat ascites hepatoma cells (AH7974). In these Con A-treated cells, the association of cytoplasmic proteins with cell membranes was suggested by observing their Triton shells. The transition from G-actin to F-actin occurred in these cells. The association of membrane lipid with cytoplasmic proteins extracted from AH cells was studied by the isolation of protein-bound liposomes and phase transition release. The analysis of isolated liposomes revealed that many cytoplasmic proteins which specifically associated with liposomes were cytoskeletal elements including F-actins. The association of proteins with liposomes was affected by the lipid composition of the liposomal membrane and by the Ca2+ concentration of the incubation medium. The strong interaction of liposomal membrane with cytoplasmic proteins or isolated cytoskeletal proteins was demonstrated also by phase transition release using carboxy fluorescein-containing liposomes. These experiments showed that there was a strong affinity between lipid membrane and cytoskeletal elements including F-actins and that the amount of F-actin increased due to Con A treatment. The association of the submembranous microfilaments with the cell membrane may contribute to capping of the cells caused by Con A.</p

Estimating Time-Varying Origin-Destination Flows from Link Traffic Counts

A dynamic model for estimating real-time origin-destination flows from time-series of traffic counts is presented. The time variation of flows is explicitly treated as a dynamic process. The model is formulated based on minimizing the integrated squared error between predicted and observed output traffic counts over the period of observation. An efficient solution method is developed by using Fourier transformation and illustrated with numerical examples. The numerical simulation experiment shows that the system dynamic approach may be particularly suitable for on-line traffic management and control in urban transportation systems

Orbital Evolution of Close-in Super-Earths Driven by Atmospheric Escape

The increasing number of super-Earths close to their host stars have revealed a scarcity of close-in small planets with 1.5–2.0 R⊕ in the radius distribution of Kepler planets. The atmospheric escape of super-Earths by photoevaporation can explain the origin of the observed “radius gap.” Many theoretical studies have considered the in situ mass loss of a close-in planet. Planets that undergo atmospheric escape, however, move outward due to the change in the orbital angular momentum of their star–planet systems. In this study, we calculate the orbital evolution of an evaporating super-Earth with a H₂/He atmosphere around FGKM-type stars under stellar X-ray and extreme-UV irradiation (XUV). The rate of increase in the orbital radius of an evaporating planet is approximately proportional to that of the atmospheric mass loss during a high stellar XUV phase. We show that super-Earths with a rocky core of ≲10 M⊕ and a H₂/He atmosphere at ≲0.03–0.1 au (≲0.01–0.03 au) around G-type stars (M-type stars) are prone to outward migration driven by photoevaporation. Although the changes in the orbits of the planets would be small, they would rearrange the orbital configurations of compact, multiplanet systems, such as the TRAPPIST-1 system. We also find that the radius gap and the so-called “Neptune desert” in the observed population of close-in planets around FGK-type stars still appear in our simulations. On the other hand, the observed planet population around M-type stars can be reproduced only by a high stellar XUV luminosity model

Critical Core Masses for Gas Giant Formation with Grain-Free Envelopes

We investigate the critical core mass and the envelope growth timescale, assuming grain-free envelopes, to examine how small cores are allowed to form gas giants in the framework of the core accretion model. This is motivated by a theoretical dilemma concerning Jupiter formation: Modelings of Jupiter's interior suggest that it contains a small core of < 10 Earth mass, while many core accretion models of Jupiter formation require a large core of > 10 Earth mass to finish its formation by the time of disk dissipation. Reduction of opacity in the accreting envelope is known to hasten gas giant formation. Almost all the previous studies assumed grain-dominated opacity in the envelope. Instead, we examine cases of grain-free envelopes in this study. Our numerical simulations show that an isolated core of as small as 1.7 Earth mass is able to capture disk gas to form a gas giant on a timescale of million years, if the accreting envelope is grain-free; that value decreases to 0.75 Earth mass, if the envelope is metal-free, namely, composed purely of hydrogen and helium. It is also shown that alkali atoms, which are known to be one of the dominant opacity sources near 1500 K in the atmospheres of hot Jupiters, have little contribution to determine the critical core mass. Our results confirm that sedimentation and coagulation of grains in the accreting envelope is a key to resolve the dilemma about Jupiter formation.Comment: 17 pages, 2 figures, 1 table, Accepted for publication in Ap

Autophagy May Precede Cellular Senescence of Bile Ductular Cells in Ductular Reaction in Primary Biliary Cirrhosis

Background and Aim: Recent studies disclosed that autophagy facilitates the process of senescence. Given that cellular senescence is involved in the pathophysiology of ductular reaction (DR) in primary biliary cirrhosis (PBC), we examined an involvement of autophagy in DRs in PBC and control livers. Methods: We examined immunohistochemically the expression of microtubule-associated proteins light chain 3β (LC3) as autophagy marker, p62/sequestosome-1 (p62) as autophagy-related marker in bile ductular cells in livers taken from the patients with PBC (n = 42), and control livers (n = 100). The expression of senescent markers (p16INK4a and p21WAF1/Cip1) in bile ductular cells and their correlation with autophagy was also evaluated. Results: The expression of LC3 was seen in coarse vesicles in the cytoplasm of bile ductular cells and significantly more frequently in PBC of both early and advanced stages when compared to control livers (p < 0.01). The expression of p62 was seen as intracytoplasmic aggregates and significantly more frequently in PBC when compared to control livers (p < 0.05). The expression of LC3 and p62 significantly correlated with each other (p < 0.01). The expression of LC3 and p62 significantly correlated with the expression of p16INK4a, p21WAF1/Cip1 (p < 0.05). Conclusions: Autophagy is frequently seen in bile ductular cells in DRs in PBC. Since cellular senescence of bile ductular cells is rather frequent in the advanced stage of PBC, autophagy may precede cellular senescence of bile ductular cells in DRs in PBC. © 2011 Springer Science+Business Media, LLC

The Effect of Grazing on Fecal Shedding of Pathogenic Escherichia coli in Beef Cattle

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Gravitational scalar field coupled directly to the Maxwell field and its effect to solar-system experiments

The effect of the massless gravitational scalar field assumed to couple directly to the Maxwell field to the solar-system experiments is estimated. We start with discussing the theoretical significances of this coupling. Rather disappointingly, however, we find that the scalar-field parameters never affect the observation in the limit of the geometric optics, indicating a marked difference from the well-known contribution through the spacetime metric.Comment: LaTex 10 page