Development of microwave ion source for industrial applications.

A microwave ion source is one of the long-life ion sources. In this paper, we report on the characteristics of the extracted Ar ion beam produced by a microwave ion source under various conditions, in terms of magnetic flux distribution and mass flow, and the stability of the ion beam. The measured spectra show that, under the experimental condition, almost all of produced ions were Ar(+) ions. For more than 6 h, the ion beam was stable.

Effect of mouth breathing on masticatory muscle activity during chewing food.

The aim of this study was to examine the effect of mouth breathing on masticatory muscle activity during chewing food. Masseter muscle activity during chewing of a rice ball was recorded in 45 adult volunteers (three women), identified as nose breathers. Surface electrodes were placed on the skin according to the orientation of the masseter muscle to record the activity of this muscle while the subjects chewed the food until swallowing. Each activity was recorded twice, once with nose breathing and once with mouth breathing induced by nasal obstruction. The integrated and mean electromyography values for mouth breathing were significantly lower than the values for nose breathing (P < 0·05). The resting and total duration of chewing were significantly prolonged (P < 0·05) and the active duration significantly shorter (P < 0·05) when breathing through the mouth compared with the nose. Significantly more chewing strokes were counted for mouth breathing compared with nose breathing (P < 0·05). Taken together, the results indicate that mouth breathing decreases chewing activity and reduces the vertical effect upon the posterior teeth.

Possible active transport mechanism in pharmacokinetics of flunixin-meglumin in rabbits.

The plasma and urine kinetics of flunixin-meglumin (FNX, 2 mg/kg, i.v.) in rabbits were examined. Unusual pharmacokinetic profiles were obtained, including high binding percentage with plasma protein (> 99%), a short elimination half-life (< 4 hr) and a relatively large Vd-area (0.5 L/kg). These profiles indicate that some active transport mechanisms are involved in FNX disposition. The recovery of FNX from urine was approximately 9 % of the dose within 24 hr following the injection. The estimated renal clearance of the unbound drug nearly corresponded to the renal blood flow rates, indicating that active tubular secretion in the renal re-absorptive tract may be involved in the disposition. The effect of a concomitant administration of pravastatin (PV) on FNX disposition was also examined. PV is a representative substrate of a transporter in human liver cells (OATP-2). After the PV administrations, the Vd-area of FNX and total body clearance markedly decreased, indicating that FNX is actively taken up and metabolized in liver cells by an OATP-2 like transporter. In conclusion, there are at least 2 active transport pathways for FNX pharmacokinetics in rabbits, one is renal tubular secretion and the other is in the sinusoidal section of the liver.