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Background: Pharyngeal cooling decreases brain temperature by cooling carotid arteries. This study was designed to evaluate the principle of pharyngeal cooling in monkeys and humans. Methods: Monkeys (n ϭ 10) were resuscitated following 12 min of cardiac arrest. Pharyngeal cooling (n ϭ 5), in which cold saline (5°C) was perfused into the cuff at the rate of 500 ml/min, was initiated simultaneously with the onset of resuscitation for 30 min. Patients (n ϭ 3) who were in an intensive care unit were subjected to 30 min of pharyngeal cooling under propofol anesthesia. Results: In the animal study, core brain temperature was significantly decreased compared with that in the control

We report a facile method for preparing a silica (SiO 2 )-based material containing Sn nanoparticles (NPs) distributed inside for enhancing the thermal cyclic stability of the inserted Sn NPs. Absorption of a Sn precursor (i.e., an aqueous SnCl 2 solution) into a mesoporous SiO 2 matrix resulted in confinement of the Sn precursor in a mesoporous SiO 2 matrix. Hydrogen thermal reduction of the above composite yielded Sn nanoparticles with a diameter of ca. 30 nm uniformly distributed inside porous SiO 2 (p-SiO 2 ) spheres: Sn NPs@p-SiO 2 . Our investigation of the transformation of the porous SiO 2 structure to hold Sn NPs revealed that the process was closely related to the transformation of the amorphous hydrolyzed Sn precursor into Sn oxides followed by, probably, the rearrangement of the SiO 2 matrix via its interaction with the melting Sn. This led to the formation of stable Sn NPs@p-SiO 2 . The SiO 2 matrix effectively prevented the coalescence of the Sn NPs, and the obtained product exhibited negligible changes in melting behavior during the second to 100th cycle of a freeze− melt cycle test.

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We speculate that flow separation at the most proximal site of the side-hole induces stagnation of flow and induces energy loss. This flow separation may hamper the main stream from the end-hole inlet, which is most effective with low shear stress. The EH cannula was associated with the best flow rate and flow profile. However, by increasing side-hole numbers, flow separation occurs on each side-hole, resulting in more energy loss than the EH cannula and flow rate reduction.