Search

Extracellular ATP released from stimulated and/or damaged cells modulates physiological responses via stimulation of various purinoceptors. We previously showed that ATP potentiated the Ag-induced mast cell (MC) degranulation via purinoceptors pharmacologically similar to the ionotropic P2X4 receptor. In this study, we investigated the role of P2X4 receptor in MC degranulation induced by stimulation of IgE-Fc«RI complex with Ag, using bone marrow-derived MCs (BMMCs) prepared from wild type and P2X4 receptor-deficient (P2rx42/2) mice. ATP significantly increased Ag-induced degranulation in BMMCs prepared from wild type mice. This effect of ATP was reduced in BMMCs prepared from P2rx42/2 mice. The potentiating effect of ATP was restored by expressing P2X4 receptor in P2rx42/2 BMMCs. The P2X4 receptor-mediated effects were maintained even after differentiating into the connective tissue-type MCs. P2X4 receptor stimulation did not affect the Ag-induced Ca2+ response but enhanced Ag-induced early signals, such as tyrosine phosphorylation of Syk and phospholipase C-g. Interestingly, these effects of ATP on Syk phosphorylation were not impaired by pretreatment with Cu2+, an inhibitor of the P2X4 receptor channel, or removal of external Ca2+, suggesting that a mechanisms other than Ca2+ influx through ion channel activity may be involved. In vivo experiments revealed that systemic and intradermal passive anaphylaxis responses were significantly alleviated in P2rx42/2 mice. Taken together, the present data suggest that the P2X4 receptor plays an essential role in ATP-induced upregulation of MC degranulation in response to Ag, and also contributes to the Ag-induced allergic response in vivo. [ABSTRACT FROM AUTHOR]

We report the first all-optical production of dual Bose–Einstein condensates (BECs) of paired 6Li (fermion) and one spin state of 7Li (boson) at the magnetic field where the s-wave interactions between fermions are resonant. Fermions are cooled efficiently by evaporative cooling and they serve as coolant for bosons. As a result, the dual condensates can be achieved by using a simple experimental apparatus and procedures, as in the case of the all-optical production of a single BEC. We show that the all-optical method enables us to realize variety of ultracold Bose–Fermi mixtures. [ABSTRACT FROM AUTHOR]

The article presents an array analysis of dispersive tsunamis to locate the tsunami source within the submarine Smith Caldera. It mentions possibility of finding a source mechanism with efficient tsunami but inefficient seismic radiation that can satisfactorily explain both the tsunami and seismic observations, if indeterminacy of a shallow moment tensor source is given.

We recorded P and S waves traveling through the oceanic lithosphere-asthenosphere system (LAS) using broadband ocean-bottom seismometers in the northwest Pacific, and we quantitatively separated the intrinsic (anelastic) and extrinsic (scattering) attenuation effects on seismic wave propagation to directly infer the thermomechanical properties of the oceanic LAS.The strong intrinsic attenuation in the asthenosphere obtained at higher frequency (~3 hertz) is comparable to that constrained at lower frequency (~100 seconds) by surface waves and suggests frequency-independent anelasticity, whereas the intrinsic attenuation in the lithosphere is frequency dependent.This difference in frequency dependence indicates that the strong and broad peak dissipation recently observed in the laboratory exists only in the asthenosphere and provides new insight into what distinguishes the asthenosphere from the lithosphere. [ABSTRACT FROM AUTHOR]