Pressure-tuned First-order Phase Transition and Accompanying Resistivity Anomaly in CeZn_{1-\delta}Sb_{2}

The Kondo lattice system CeZn_{0.66}Sb_{2} is studied by the electrical resistivity and ac magnetic susceptibility measurements at several pressures. At P=0 kbar, ferromagnetic and antiferromagnetic transitions appear at 3.6 and 0.8 K, respectively. The electrical resistivity at T_N dramatically changes from the Fisher-Langer type (ferromagnetic like) to the Suzaki-Mori type near 17 kbar, i.e., from a positive divergence to a negative divergence in the temperature derivative of the resistivity. The pressure-induced SM type anomaly, which shows thermal hysteresis, is easily suppressed by small magnetic field (1.9 kOe for 19.8 kbar), indicating a weakly first-order nature of the transition. By subtracting a low-pressure data set, we directly compare the resistivity anomaly with the SM theory without any assumption on backgrounds, where the negative divergence in d\rho/dT is ascribed to enhanced critical fluctuations in the presence of superzone gaps.Comment: 5 pages, 4 figures; journal-ref adde

Lafutidine, a Protective H2 Receptor Antagonist, Enhances Mucosal Defense in Rat Esophagus

Luminal acid or CO2 induces a hyperemic response in the esophagus, via activation of acid sensors on capsaicin-sensitive afferent nerves (CSAN). Since disruption of the hyperemic response to luminal CO2 acidifies the interstitium of the esophageal mucosa, the hyperemic response may maintain interstitial pH (pHint). We hypothesized that acid-related hyperemia maintains pHint, preventing acid-induced injury in the esophageal mucosa. We examined the effects of capsaicin (Cap) or lafutidine (Laf), a mucosal protective H2 antagonist, on the regulation of pHint and blood flow in rat esophagus using ratiometric microimaging and laser-Doppler measurements of the lower esophageal mucosa of living rats. The esophagus was topically superfused with pH 7.0 buffer, or a pH 1.0 or pH 1.0 + pepsin (1 mg/ml) solution with or without Laf. Cap (30 or 100 µM) or Laf (0.1 or 1 mM) dose-dependently increased blood flow, accompanied by increased pHint. The pH 1.0 solution increased blood flow without pHint change, whereas Laf (1 mM) increased blood flow and pHint during acid exposure. The effects of Laf were abolished by ablation of CSAN. Perfusion of the acidified pepsin solution gradually decreased pHint, inhibited by Laf perfusion. Activation of CSAN by Laf with or without acid, accompanied by hyperemia, increased pHint, preventing acidified pepsin-induced interstitial acidification. Stimulation of the capsaicin pathway with compounds such as Laf enhances mucosal protection from acid-related injury in the upper gastrointestinal tract

Balance Functions, Correlations, Charge Fluctuations and Interferometry

Connections between charge balance functions, charge fluctuations and correlations are presented. It is shown that charge fluctuations can be directly expressed in terms of a balance functions under certain assumptions. The distortion of charge balance functions due to experimental acceptance is discussed and the effects of identical boson interference is illustrated with a simple model.Comment: 1 eps figure included. 5 pages in revtex