Search PubMed⌕ Search

Biomedical subjects

S Saida

Publications and source records attributed to S Saida.

17 recordsLinked to original sources
PubMed1998

Methodological caveats for monitoring binocular eye position with nonius stimuli.

Three experiments, using two sets of Nonius lines placed in a random-dot stereogram, indicated that Nonius alignment does not always reflect binocular eye position and, thus, a caveat is necessary when Nonius alignment is used to monitor binocular eye position. We found that: (a) two Nonius lines with visual line values that differed by up to 7.6 min of arc can appear aligned; (b) the two lines of each of the two Nonius sets continued to appear aligned despite a change in vergence angle of 5.9 min of arc; and (c) the Nonius alignment reflected eye position better, when the binocular dots near the Nonius lines were eliminated.

Adult↗
PubMed1996

How is motion disparity integrated with binocular disparity in depth perception?

Two experiments presented motion disparity conflicting with binocular disparity to examine how these cues determined apparent depth order (convex, concave) and depth magnitude. In each experiment, 8 subjects estimated the depth order and depth magnitude. The first experiment showed the following. (1) The visual system used one of these cues exclusively in selecting a depth order for each display. (2) The visual system integrated the depth magnitude information from these cues by a weighted additive fashion if it selected the binocular disparity in depth order perception and if the depth magnitude specified by motion disparity was small relative to that specified by binocular disparity. (3) The visual system ignored the depth magnitude information of binocular disparity if it selected the motion disparity in depth order perception. The second experiment showed that these three points were consistent whether the subject's head movement or object movement generated motion disparity.

Adult↗
PubMed1995

The contribution of color to depth perceived from motion parallax.

Perceived depth was measured in a colored stimulus while stimulus movement yoked to head displacement simulated a depth of 1 cm. Velocity judgments were also made for similar stimuli moving at the same average speed but without head movement. Both measures decreased to a minimum of about 30-40% of the veridical values when the stimuli were equiluminous. Perceived depth and speed also decreased for a monochromatic stimulus as a function of luminance contrast but much more abruptly than for the chromatic stimuli. The results indicate that equiluminous color stimuli contribute to the perception of depth from motion parallax and that the contribution is not mediated by residual luminance.

Color Perception↗
PubMed1993

Tactile pattern recognition by graphic display: importance of 3-D information for haptic perception of familiar objects.

Haptic recognition of familiar objects by the early blind, the late blind, and the sighted was investigated with two-dimensional (2-D) and three-dimensional (3-D) stimuli produced by small tactor-pins. The 2-D stimulus was an outline of an object that was depicted by raising tactor-pins to 1.5 mm. The 3-D stimulus was a relief that was produced by raising the tactors up to 10 mm, corresponding to the height of the object. Mean recognition times for correct answers to the 3-D stimuli were faster than those for the 2-D stimuli, in all three subject groups. No statistically significant differences in percentage of correct responses between the 2-D and the 3-D stimuli were found for the late-blind and sighted groups, but the early-blind group demonstrated a significant difference. In addition, the haptic legibility for the quality of depiction of the object, without regard to whether or not the stimulus was understood, was measured. The haptic legibility of the 3-D stimuli was significantly higher than that of the 2-D stimuli for all the groups. These results suggest that 3-D presentation seems to promise a way to overcome the limitations of 2-D graphic display.

Adult↗
PubMed1990

The effect of middle ear effusions from children on in vitro ciliary activity.

In an attempt to clarify the effect of middle ear effusions (MEEs) on ciliary activity, the ciliary beat frequency (CBF) of nasal epithelium from normal subjects was determined following incubation in Hanks' solution containing effusions from pediatric otitis media with effusion. Both serous and mucoid types of effusions increased CBF 15 min after incubation. The mucoid type of effusion was then found to decrease CBF 6 h after incubation. Since the pH and osmotic pressure of the solution containing the effusions were within the physiological ranges for normal ciliary beating, our findings show that MEEs can influence CBF in vitro.

Child↗
PubMed1990

[A study of microdensitometric evaluation of opacity of maxillary sinuses in patients with nasal allergy].

The opacity of the maxillary sinuses on X-ray film in Waters' view in patients with nasal allergy was evaluated by a microdensitometer. The patients with nasal allergy were diagnosed with the positive results of the following; 1) eosinophilia in nasal secretion, 2) nasal provocation test, 3) intradermal skin test or radioallergosorbent test (RAST). The ratio of density of the maxillary sinuses and orbits was determined by a microdensitometer, and the ratio of the average degree of the opacity of the maxillary sinus to that of the ipsilateral orbit was designated as the M/O ratio. The normal range of the M/O ratio was set over the mean value -2 standard deviations in the normal group. The results are followings. 1) The abnormal shadows in the maxillary sinuses were found out to be 36.9% in patients with nasal allergy. 2) Patients under 15 years old had significantly higher incidence of abnormal shadows, especially in the bilateral sinuses compared with patients over 15 years old. 3) Polyps in the maxillary sinus were recognized in 5.0% of all the sinuses. 4) There were no significant differences for the incidence of abnormal shadow among the patients with nasal allergy caused by different antigens.

Absorptiometry, Photon↗
PubMed1989

The roles of convergence and apparent distance in depth constancy with motion parallax.

The question of whether motion parallax is calibrated by convergence or by apparent distance for depth perception was addressed in three experiments. In Experiment 1, a random dot parallactic display was viewed monocularly at a distance of 80 cm, and the convergence angles were set for distances of 40, 60, and 80 cm. Averaged apparent depth was not different across conditions. In Experiment 2, a display consisting of one surface showing dollar bills and one surface showing random dots was viewed monocularly at a distance of 80 cm. It was presented at two different apparent distances, which were manipulated by varying the size of the dollar bills. In one condition, normally sized dollar bills were presented, and in another condition, the size was reduced by 30%. The averaged apparent depth associated with the small-bill display was larger than the depth associated with the normally sized bill display. In Experiment 3, a random dot display was viewed monocularly at 120 cm. In the primary condition, the random dot display was viewed with an induction screen at 80 cm, and it was moved from side to side such that it appeared stationary and close to the plane of the induction screen. In a comparison condition, the display was viewed without the induction screen and was moving from side to side at 120 cm. In another comparison condition, the display was again viewed without the induction screen but was stationary at 120 cm. Observers adjusted the extent of motion parallax so that apparent depth was 1 cm. The mean extent of parallax was larger in the primary conditio.(ABSTRACT TRUNCATED AT 250 WORDS)

Accommodation, Ocular↗
PubMed1985

Interaction between mucociliary transport and the ciliary beat of chicken nasal mucosa.

We studied the relationship between the mucociliary transport time and the ciliary beat frequency in the chicken nares following water deprivation and topical administrations of cocaine, atropine, and Newcastle disease virus (NDV). Dehydration produced progressive decelerations of mucociliary flow but not ciliary beat frequency. In vivo 5% cocaine resulted in decreased sinus mucociliary transport time, while application of 20% cocaine to in vitro tissues caused ciliary paralysis within 5 min. Topical atropine was seen to affect both mucociliary flow and the ciliary beat frequency. NDV infection induced deceleration of the turbinate clearance time after 72 h, but did not change ciliary beat frequency. By day 12, mucociliary flow remained unchanged although ciliary beat frequency decreased significantly. Our results support the general concept that mucus is more important than are the cilia in normal nasal mucociliary function.

Animals↗
PubMed1985

Reversibility of reduced mucociliary clearance in chronic sinusitis.

Nasal mucociliary clearance was measured before and after treatment in patients with chronic sinusitis. Nasal mucociliary transit time before the study was greater than 36 min in 8 out of 14 patients who were treated with S-carboxymethylcysteine, and in 9 out of 22 patients who were treated by repeated antral lavage. The nasal mucociliary clearance was significantly improved by both treatment regimens. This may indicate that the malfunction of the nasal mucociliary system is not the cause of chronic sinusitis but an effect of chronic inflammation of the respiratory mucosa.

Adolescent↗
PubMed1985

Cilia injury during virus infection in chickens.

The reduction of mucociliary clearance in the Newcastle disease virus-B infected nasal turbinate in chickens is mainly due to ciliary pathology, decrease of the number of cilia and of the ciliary beat frequency.

Animals↗
PubMed1984

Interaction between saccade and tracking vergence.

Additivity of saccade and tracking vergence was examined. Binocular eye movements were measured photoelectrically while subjects tracked a target moving smoothly on a radial line with an interpolated step change to a new radial line. Examining the abrupt portions of the two eyes' movements, we found the durations were almost the same for the two eyes, but that there were reliable differences in the magnitudes which were too large to be understood by an additivity hypothesis.

Adult↗
PubMed1982

Computer-controlled TVSS and some characteristics of vibrotactile letter recognition.

A computer-controlled vibrotactile display against the abdomen was used to investigate recognition performance of Katakana characters as a function of 3 display modes. The superior performance (about 95% correct) is achieved when the letter is presented sequentially as if it were being written. The other two modes (the entire letter is presented at once, the letter is moved horizontally across the display) allow only 20 to 40% correct recognition.

Adult↗
PubMedDate not supplied

Effect of lipopolysaccharide of Haemophilus influenzae on ciliary activity of the human nasal mucosa and bullfrog palate clearance.

The influence of lipopolysaccharide (LPS) of Haemophilus influenzae on the ciliary activity of human nasal mucosa was first studied using both a photo-oscillographic apparatus and by bullfrog palate clearance. Neither modification of ciliary activity nor change in bullfrog palate clearance was observed in the early phase after the administration of LPS.

Animals↗