600 research outputs found
Changes in cell volume in pancreatic duct cells. Effect of secretagogues and CFTR expression
No full textPrevious results from our group have demonstrated that, in CFTR-transfected murine C127 cells incubated under Cl--free conditions, "isotonic" shrinkage is more rapid in CFTRw/t than in CFTRΔF508 cells, a difference overcome in the latter model by the addition of exogenous ATP. Moreover, compared with ΔF508 cells, isotonic cell shrinkage of CFTRw/t -expressing cells is associated with a significantly higher ATP extrusion (Rotoli et al., Biochem. Biophys. Res. Commun. 227, 755-761 1996). In the present report changes in cell volume and ion content occurring during secretory processes are evaluated in pancreatic duct cells. The models employed were pancreatic carcinoma cells which express normal (CAPAN-1 line) or ΔF508 (CFPAC-1 line) CFTR. Under isotonic conditions, in CFTR-expressing CAPAN-1 cells secretin or 8-Br-cAMP/ teophilline mixture cause a 30% cell shrinkage associated to significant losses of sodium, chloride, and bicarbonate, as demonstrated by significant changes in cytoplasmic pH. These changes are not observed in ΔF508CFTR CFPAC-1 cells but are mimicked by ATP treatment. As in C127 cells, also in pancreatic duct cells Cl--free incubation triggers isotonic shrinkage and ATP extrusion which is greater in CAPAN-1 than in CFPAC-1 cells. These results suggest that ATP may be involved in the modifications of ion channel activities which occur during secretion in pancreatic duct cells
Chaotic dynamics in the map model of fluxon propagation in long Josephson junctions
No full textChaotic dynamics in a model of a long Josephson junction (LJJ) is studied via standard techniques of non-linear maps. A characterization of chaos in such objects in terms of Lyapunov exponents and Poincaré sections is given. Finally the occurrence of chaos in map dynamics is compared with preliminary results of full numerical integration of the perturbed sine-Gordon equation (PSGE)
Validity of Laplace formula and dependence of surface tension on curvature in second gradient fluids
No full text[No abstract available
Macroscopic quantum tunneling and the "cosmic" Josephson effect
No full textWe discuss the possible influence of a cosmic magnetic field on the macroscopic quantum tunneling process associated, in a cosmological context, to the decay of the "false vacuum." We find a close analogy with the effects of an external magnetic field applied to a Josephson junction in the context of low-temperature/high-temperature superconducting devices
Mutual inductance effects in rf driven planar Josephson junctions arrays
No full textPACS. 85.25.Am Superconducting device, characterization, design, and modeling[:AND:] 85.25.Dq Superconducting logic elements and memory devices,
Erratum: Functional analysis of OCTN2 and ATB0,+ in normal human airway epithelial cells (PLoS ONE (2020) 15:2 (e0228568) DOI: 10.1371/journal.pone.0228568)
No full textThere is an error in reference 12. The correct reference is: Ingoglia F, Visigalli R, Rotoli BM, Barilli A, Riccardi B, Puccini P, et al. (2016) Functional activity of L-carnitine transporters in human airway epithelial cells. Biochim Biophys Acta. 1858(2):210–9. 10.1016/j.bbamem.2015. 11.013
Inverse ac Josephson effect in long junctions
No full textIn highly hysteretic long Josephson junctions irradiated with microwaves the rf-induced current steps can cross the zero-current axis. The quantized voltage states arise from the phase locking of fluxon oscillations, which in rf-driven junctions can occur even with negative current bias. This phenomenon is interesting both for nonlinear dynamics and for application to the Josephson voltage standard
SUPPRESSION OF CHAOS IN THE PERTURBED SINE-GORDON SYSTEM BY WEAK PERIODIC SIGNALS
No full textSuppression of temporal phase locked chaos in the perturbed sine-Gordon system is demonstrated by numerical simulations of the full equation in the presence of two harmonic signals. Results have been compared with a simple perturbative approach for the soliton dynamics
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