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A simple MEMS optical fiber pressure sensor with the Fabry-Perot interferometer configuration is constructed that is based on a square silicon diaphragm and the intensity demodulation technology. A large area ratio of the moving mirror to the stationary one is employed to minimize the non-planarity of the deflection, and a reference light generated by a 2×2 optical fiber coupler is used to reduce the errors that are produced by the intensity variations of the light source. The theoretical analysis, simulation and experimental results all show that the pressure sensor has reasonable sensitivity, stability and measurement range. With a low cost and simple fabrication process, this sensor has great potentials for mass production and commercialization. [ABSTRACT FROM AUTHOR]

Background and Aim: To investigate the effects of serum and ascitic fluid from rats with acute pancreatitis (AP) on cellular free calcium concentration ([Ca2+]i) of isolated rat pancreatic acinar cells, and the intervention of pyrrolidine dithiocarbamate (PDTC) and tetrandrine (Tet) to cellular calcium overload in AP. Methods: AP was induced in Sprague–Dawley rats with a retrograde pancreatic duct injection of 3% sodium deoxycholate, and confirmed by histopathological examination and amylase activity assay. The rat serum and ascitic fluid were collected at 1, 5 and 10 h after AP induction, and used as irritants on isolated rat pancreatic acinar cells. The effects on intracellular [Ca2+]i, and cell viability were examined. Then, the antagonistic effects of different concentrations of PDTC and Tet were assessed. Results: The irritation with AP serum and ascitic fluid reduced the survival rate of the isolated rat pancreatic acinar cells and increased the cellular [Ca2+]i significantly ( P < 0.05). As AP induction course prolonged, the stimulation effect of the AP serum and ascitic fluid intensified. In the pretreated acinar cells with PDTC or Tet, the decreased cell vitality reverted. The elevation of [Ca2+]i in the acinar cells significantly ameliorated (significant, P < 0.05; very significant, P < 0.01). Conclusion: The serum and ascitic fluid from AP rats drastically elevate the [Ca2+]i in isolated pancreatic acinar cells and decrease cell vitality, while the pretreatment of cells with PDTC and Tet offsets the calcium overload irritated by the AP serum and ascitic fluid and protects these isolated acinar cells. [ABSTRACT FROM AUTHOR]