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排序方式: 共有484条查询结果,搜索用时 15 毫秒
61.
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Kenneth MC Cheung Jing-ping Wu Qing-he Cheng Bonnie SC Ma Ji-chang Gao Keith DK Luk 《Journal of orthopaedic surgery and research》2007,2(1):16-5
Background
Thoracoscopic anterior release has been shown that it can effectively improve spinal flexibility in animal and human cadaveric studies, and has been advocated for use in patients with scoliosis. This prospective case series aims to investigate the improvement of the spinal flexibility and the effectiveness in deformity correction by anterior thoracoscopic release and posterior spinal fusion. 相似文献63.
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The majority (217/325, 66%) of the neurons in the middle temporal (MT)
area/V5 show strong antagonistic surrounds, defined here by a decrease of
at least 50% in the summation curve. We mapped the antagonistic surround in
145 such cells, using eight circularly distributed surround stimulus
patches (Surround Asymmetry Test, SAT) and also mapped the surround in 51
of these 145 cells using a grid consisting of 25 square patches (Surround
Mapping Test, SMT). Both tests showed that the angular surround
distribution was non-uniform in the majority of these neurons. In half the
neurons, the antagonistic surround was asymmetric, and arose from a single
region on one side of the excitatory receptive field (ERF). In another
quarter of the sample the surround was bilaterally symmetric, and arose
from a pair of regions on opposite sides of the ERF. Only the remaining 20%
showed a circularly symmetric surround distribution. These three groups
differed in their laminar distribution. The SMT showed that, radially, the
surround antagonism reached a maximum, on average, at 1.5 times the ERF
radius. Detailed comparisons of the spatial relationships of excitatory and
inhibitory regions of the RF components shows that non-homogeneity of the
surround influence appears to be an intrinsic property of the surround.
Such a property may underly the extraction of the surface orientation and
curvature from speed patterns.
相似文献
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W Wasowicz J Kantorski D Perek S Popadiuk 《Zeitschrift für klinische Chemie und klinische Biochemie》1989,27(7):413-418
Zinc concentrations and Cu, Zn superoxide dismutase activity in erythrocytes were investigated in 138 healthy children and in 35 children with cancer. The mean zinc concentration in the erythrocytes of healthy children was found to be age-dependent. In the youngest group (children up to 1 year of age) the zinc concentration in erythrocytes is 18.8 +/- 3.4 micrograms/g Hb (5.89 +/- 1.23 mg/l packed cells), which is significantly lower than in other age groups. A strong logarithmic correlation (r = 0.327, p less than 0.0001 and r = 0.436, p less than 0.00001) was found between age and zinc concentration in erythrocytes, expressed as microgram/g Hb and as mg/l packed red cells, respectively. Cancer children were divided into two groups (neuro- and nephroblastoma). In the group of children with neuroblastoma no statistical differences in zinc concentration or enzyme activity were observed. In the patients with nephroblastoma, significantly higher zinc concentrations (p less than 0.05) were observed in erythrocytes. The changes of zinc concentration are accompanied by significant (p less than 0.02) decreases of enzyme activity. In this group of cancer children, statistically significant differences were observed in the zinc concentrations in erythrocytes (microgram/g Hb) between the second and the third stages of the disease. No correlation was observed between the concentration of zinc and enzyme activity in healthy children or in cancer children. 相似文献
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End-stage periventricular leukomalacia: MR evaluation 总被引:3,自引:0,他引:3
A prospective study was performed to assess the capabilities of magnetic resonance (MR) imaging in evaluation of end-stage periventricular leukomalacia (PVL) in six children, aged 31-54 months, in whom PVL had been documented by neurologic ultrasonography during the neonatal period. Eight children of similar age (four premature infants and four full-term infants) with normal neurologic development served as controls. A characteristic triad of PVL abnormalities was seen on MR images: (a) abnormally increased periventricular white-matter signal intensity on the first and second echo images of a T2-weighted sequence (repetition time = 2,000-2,400 msec, echo times = 20 or 30 and 80 msec), most commonly observed in the trigone regions of the lateral ventricles bilaterally; (b) marked loss of periventricular white matter in these regions of abnormal signal intensity, predominantly in the periatrial regions; and (c) compensatory focal ventricular enlargement adjacent to regions of abnormal signal intensity. In patients with the classic periatrial distribution of PVL lesions, general correlation between the degree of neurologic impairment and the severity of MR abnormalities was demonstrated. MR imaging was useful in detecting subtle forms of PVL in cases in which neurologic damage was subclinical. 相似文献