<ORIGINAL ARTICLE>Inhibitory effects of extracellular ATP on the Ca^<2+> mobilization evoked by muscarinic stimulation in rat parotid acinar cells

In rat parotid acinar cells, extracellular ATP reduced the increase in cytosolic Ca^ concentration ([Ca^]_i) induced by the muscarinic receptor agonist carbachol (CCh) dose-dependently. This inhibitory effect was also observed in the absence of extracellular Ca^, indicating that the Ca^ release from intracellular Ca^ stores was prevented by ATP. Formation of inositol trisphosphate induced by CCh stimulation was strongly attenuated in the presence of extracellular ATP, suggesting that the effect of ATP on the CCh-induced [Ca^]_i response was the result of a decreased phosphoinositide hydrolysis. Extracellular ATP had no effect on the CCh-induced increase in [Ca^] j in rat lacrimal acinar cells that lack the purinergic receptors. This result supports the view that the inhibitory effect of ATP on the CCh-induced [Ca^]_i response in parotid acinar cells is mediated through activation of the purinergic receptros. In rat parotid acinar cells, the purinergic receptors may play a role in modulating the activity of muscarinic receptors

<ORIGINAL ARTICLE>Characterization of a new coagulant enzyme isolated from Trimeresurus okinavensis (Himehabu snake) venom

A potent, proteinaceous inducer of coagulation factors, has been purified to homogeneity from Trimeresurus okinavensis (Himehabu snake) by ion exchange chromatography and molecular sieving. It has an apparent molecular weight of 28,000 and it specifically converts fibrinogen to fibrin through an enzymatic reaction. This activity was confirmed by a method using synthetic substrate S-2238, though the fraction from a DEAE sephacel column chromatography shows amidolytic activity of S-2251 and S-2366, which are commonly used to measure plasmin and activated protein C activity, respectively, as well as S-2238. This thrombin-like activity of the final product was not affect by the addition of heparin and AT-III. This enzyme also aggregates normal platelets. It is considered that this purified enzyme would be useful as a hemostatic agent or research reagent

Thermal Properties of Ionic Liquid + Water Binary Systems Applied to Heat Pipes

Thermal properties were investigated for binary mixtures of water and five ionic liquids: 1-butyl-3-methylimidazolium iodide ([bmim][I]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), 1-butyl-3-methylimidazolium thiocyanate ([bmim][SCN]), 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO₄]), and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][TfO]). The thermal stability was examined by thermogravimetry. The phase behavior was investigated by differential scanning calorimetry from room temperature to 153 K, and phase diagrams were constructed. Vapor pressures were measured using a static method in the temperature range of (313 to 343) K and in the concentration range of mole fraction (0 to 0.65) of ionic liquids. It was found that [emim][TfO] + H₂O mixtures are promising for working fluids in heat pipes. Loop heat pipe operation tests were also performed at (313 to 393) K using the mixtures

Effect of Dy substitution in the giant magnetocaloric properties of HoB2_{2}

Recently, a massive magnetocaloric effect near the liquefaction temperature of hydrogen has been reported in the ferromagnetic material HoB$_{2}$. Here we investigate the effects of Dy substitution in the magnetocaloric properties of Ho$_{1-x}$Dy$_{x}$B$_{2}$ alloys ($\textit{x}$ = 0, 0.3, 0.5, 0.7, 1.0). We find that the Curie temperature ($\textit{T}$$_{C}$) gradually increases upon Dy substitution, while the magnitude of the magnetic entropy change |$\Delta \textit{S}_{M}$| at $\textit{T}$ = $\textit{T}_{C}$ decreases from 0.35 to 0.15 J cm$^{-3}$ K$^{-1}$ for a field change of 5 T. Due to the presence of two magnetic transitions in these alloys, despite the change in the peak magnitude of |$\Delta \textit{S}_{M}$|, the refrigerant capacity ($\textit{RC}$) and refrigerant cooling power ($\textit{RCP}$) remains almost constant in all doping range, which as large as 5.5 J cm$^{-3}$ and 7.0 J cm$^{-3}$ for a field change of 5 T. These results imply that this series of alloys could be an exciting candidate for magnetic refrigeration in the temperature range between 10-50 K.Comment: 19 pages, 5 figures, 2 table