Nasal gas composition in humans and its implication on middle ear pressure

Chewing and acid on the tongue evoked a flow of saliva from the duct-cannulated parotid gland of the conscious rat despite pretreatment with atropine and adrenoceptor antagonists. This non-adrenergic, non-cholinergic (NANC) response depended on an intact parasympathetic innervation and was abolished by a tachykinin antagonist. The present findings are consistent with a physiological role for the secretory NANC mechanisms of the salivary glands.     

Active,passive and transpassive dissolution of a nickel base super alloy in concentrated acid mixture solution

The electrochemical and corrosion behaviour of a nickel base super alloy (C-263) has been investigated in the deaerated binary and ternary solution mixture of concentrated phosphoric acid, acetic acid, sulphuric acid, nitric acid or water using potentiostatic technique at 35°C. The possibilities of electropolishing of this alloy in these solution mixtures have been also explored. The alloy showed distinct active, passive and transpassive behaviour in the experimental solutions. The alloy remained active and turned passive in the negative potential region. Transpassive dissolution of the alloy is observed and electropolishing is achieved in this region. The best electropolishing is obtained in 50% H₃PO₄ + 40% CH₃COOH + 10% H₂SO₄. Higher content of water in the electrolytic solution is not useful for electropolishing of the alloy The experimental results also suggest that a current plateau in the transpassive potential region is not a sufficient condition to achieve electropolishing.     

Intubation conditions: importance of the rate of repetition of the train-of-four

OBJECTIVES: To assess that neuromuscular relaxation onset of the adductor pollicis (AP) is related to neuromuscular stimulation rate. To assess that train-of-four (TOF) at 0.05 Hz is a more accurate indicator of optimal tracheal intubation time and conditions, than TOF at 0.08 Hz. STUDY DESIGN: Prospective, comparative, randomized double-blind study. PATIENTS: Forty adults, physical class ASA 1 or 2, undergoing general anaesthesia with tracheal intubation were allocated to two groups (n = 20) according to the sequence of stimulation of the AP: either TOF at 0.05 Hz (test group) or TOF at 0.08 Hz (control group). METHODS: Induction of anaesthesia was achieved with thiopentone, fentanyl and vecuronium (0.1 mg.kg-1). Neuromuscular monitoring was obtained with force displacement transducers attached to each AP. Tracheal intubation was performed once AP muscular response obtained with TOF at 0.05 Hz for test group and TOF at 0.08 Hz for control group was abolished. Results are expressed as mean +/- SEM. Fisher exact test was used for intubation conditions comparison. Curarization time between groups was compared with unpaired Student's t test (P < 0.05 accepted). RESULTS: TOF with 0.05 Hz stimulation significantly increased curarization time: 217 +/- 7 versus 162 +/- 6 s (P < 0.001). Intubation conditions were excellent in 95% and good in 5% of patients in the study group, compared to 15 and 40% in the control group, respectively (P < 0.01) in 45% of the control group patients coughing at intubation occurred. CONCLUSION: Low stimulation rate (TOF at 0.05 Hz) of AP is a reliable technique to determine the appropriate intubation time for patients paralyzed with vecuronium.     

A comparison of two conformal methods for FDTD modeling

Two conformal finite-difference time-domain (FDTD) methods are considered, the contour path (CPFDTD) method of Jurgens et al. (see IEEE Trans. Antennas Propagat., vol.40, p.357, 1992) and the overlapping grid (OGFDTD) method of Yee et al. (see IEEE Trans. Antennas Propagat., vol.40, p.1068, 1992). Both TE and TM scattering from a two-dimensional (2-D), perfectly conducting circular cylinder are used to test the accuracy of the methods for curved surfaces. Also, TE and TM scattering from a 2-D, perfectly-conducting rotated square cylinder are used to test the accuracy for corners and edges. It is shown that the conformal method proposed by Yee et al. provide significant improvement in accuracy over the original FDTD algorithm for most of the geometries studied. However, implementation becomes more difficult as the geometries become more complex. The conformal method proposed by Jurgens et al. provide significant improvement in accuracy as well for most of the geometries studied. However, improvement does not occur for the TM case when the square cylinder is not aligned properly with the grid. Implementation of the CPFDTD method is relatively straightforward. For the majority of the cases studied, the OGFDTD method is more accurate than the CPFDTD method