Evaluation of effects of optokinetic and rotational stimuli with functional head impulse test (fHIT) in individuals with motion sickness.

OBJECTIVES: To evaluate effects of optokinetic and rotational stimulus in individuals with and without motion sickness (MS) using fHIT. METHODS: The study included subjects aged 18-40; 35 subjects with MS for MS group and 35 subjects without vertigo for control group. Percentage of the correct answer (% CA) with and without optokinetic stimulus (o-fHIT) in the frontal plane in the fHIT test was compared in both groups. In addition, both group subjects were seated on an ordinary rotating office chair. % CA was compared between groups by applying rotational fHIT (r-fHIT) test after the subjects were rotated randomly to the right and left and also simultaneously moved their heads in the vertical plane. RESULTS: There was no significant difference in % CA in fHIT o-fHIT and r-fHIT in the control group. Both groups showed a significant difference in % CA for fHIT, o-fHIT, and r-fHIT for all SCCs (p < 0.05). CONCLUSIONS: Since individuals with MS are affected by optokinetic and rotational stimuli, fHIT performed after these stimuli can be used as an objective confirming test for diagnosing MS.

Effect of pH and temperature on the thermostability of prickly pear (Opuntia ficus-indica) yellow-orange pigments.

The colour stability of the yellow-orange pigment (lambda max = 476 nm) of prickly pear (Opuntia ficus-indica) fruit was determined as a function of temperature and pH. The experiments were carried out at three different temperatures (50, 70 and 90 degrees C) with pigment solutions at pH values ranging from 2-7. The degree of pigment retention decreased with increasing temperature as a function of increasing thermal exposure time with least pigment degradation at pH 5. The reaction rate constants were determined as 0.0062, 0.0383 and 0.1102 min-1 for a thermal degradation reaction rate of pseudo-first order. The activation energy was calculated as 65.1 kJ.mol-1.