Biomedical subjects

Zhi-Lei Zhang

Publications and source records attributed to Zhi-Lei Zhang.

4 recordsLinked to original sources

PubMed2006

[Comparative study of the effects of Gypsum Fibrosum and Gypsum Fibrosum Preparatum in promoting granulation].

OBJECTIVE: To investigate the effects of Gypsum Fibrosum and Gypsum Fibrosum Preparatum in promoting granulation. METHODS: The wounds of muscle layer were produced in rats by using surgical operation. Two round wounds, with diameter about 1.5 cm, were cut at the depilatory area of two sides of the back of each rat, with an interval of 2 cm, deep to muscle layer, and the thickness of the knife wound of muscle layer was about 0.15 cm. Forty SD rats with the wounds were randomly divided into 4 groups: untreated group, beifuji-treated group, Gypsum Fibrosum-treated group and Gypsum Fibrosum Preparatum-treated group, with 10 rats in each group. Then the wounds were sprinkled with powders of Gypsum Fibrosum and Gypsum Fibrosum Preparatum, or sprayed with beifuji solution, respectively. The healing state of granulation tissues of the wounds was observed at the eighth and fourteenth day respectively. RESULTS: The number of fibroblasts, the number of capillary tubes and the area of capillary tubes in granulation tissue of wounds in the Gypsum Fibrosum Preparatum-treated group were significantly higher than those in the untreated group and Gypsum Fibrosum-treated group (P<0.01). There were no statistical differences between the Gypsum Fibrosum Preparatum-treated group and the beifuji-treated group. However, Gypsum Fibrosum-treated group showed no obvious differences compared to the untreated group (P>0.05). CONCLUSIONS: Gypsum Fibrosum Preparatum can accelerate the formation of collagenoblast and micrangium in wounds, and the proliferation of granulation tissues, thus promoting the skin wounds to healing. The effect of Gypsum Fibrosum is changed after being calcined, and Gypsum Fibrosum Preparatum has obvious effect in promoting granulation.

Calcium Sulfate↗

PubMed2004

Temporal aspects of spatial interactions affecting stereo-matching solutions.

Stereo-matching solutions minimize disparity relative to the horopter (minimum-absolute-disparity or MAD), and differences in disparity between adjacent features (minimum-relative-disparity or MRD). When placed in conflict, spatial proximity promotes MRD over MAD solutions. How does temporal proximity of neighboring features affect strength of these spatial interactions? We quantified the inter-stimulus interval (ISI) over which an unambiguous disparity pattern influenced stereo-matches for patterns with several possible solutions. Likelihood of MRD decreased as ISI increased (48.9 ms time constant) and increased as contrast was reduced for short ISIs, suggesting that monocular persistence (temporal impulse response) underlies the temporal interaction.

Contrast Sensitivity↗

PubMed2003

Eye movements facilitate stereo-slant discrimination when horizontal disparity is noisy.

Conditions in which saccadic gaze shifts within planar surfaces facilitate stereo-slant discrimination for slant about the horizontal and vertical axis were investigated. When horizontal disparity noise was added, large gaze shifts in the direction of the slant lowered stereo-slant discrimination thresholds compared to thresholds measured with steady central fixation, whereas eye movements orthogonal to the slant orientation did not lower slant-discrimination thresholds. When no horizontal noise was added, performance was the same with and without gaze shifts. These results suggest that slant is recovered from depth differences between target edges when horizontal disparity signals are variable and that foveal fixation improves the measures of disparity. Eye movements did not lower slant thresholds by providing multiple foveal samples of slant at different target locations that were averaged to reduce disparity noise levels, because eye movements only lowered the thresholds when there was a depth difference between the fixation points. To study which signals for azimuth are used when slant is recovered from the difference in depth between target edges, vertical disparity noise was added and stimulus height was reduced. Both methods elevated slant-discrimination thresholds when horizontal disparity noise was present, suggesting that vertical disparity is used as a cue for azimuth.

Depth Perception↗

PubMed2003

Thresholds for stereo-slant discrimination between spatially separated targets are influenced mainly by visual and memory factors but not oculomotor instability.

Surface-slant variations can be sensed either simultaneously with steady fixation or sequentially with saccadic gaze shifts. Stereo-slant discrimination thresholds are affected by visual, oculomotor, and memory factors. We have investigated the effects of fixation strategy, target separation, and exposure duration on stereo-slant discrimination. With long exposure durations (734 ms), stereo-slant discrimination thresholds measured with simultaneous presentation of test and reference stimuli were lower with gaze shifts than without them when target separations exceeded 4 deg. Above 4-deg target separations, the benefits of improved disparity resolution with foveal gaze shifts outweighed the costs of oculomotor variability associated with saccades. With short exposure durations (167 ms), as target separation increased, stereo-slant discrimination thresholds measured without gaze shifts increased with both sequential and simultaneous stimulus presentations, whereas thresholds with gaze shifts remained constant. This indicates that oculomotor errors are not an important factor in stereo-slant discrimination. In contrast to stereo-slant thresholds, sequential stereo-depth thresholds between two dots, measured with gaze shifts, increased with target separation. Thus, oculomotor error increases with target separation, and it is an important factor in stereo-depth discrimination.

Depth Perception↗