光照对胎兔视觉器官发育影响的研究

近的来众多学者对振声等刺激范围的胎教研究已广泛开展，有些已在临床实际应用中取得了良好的成效。而光照机制的研究，特别是有关胎体在光照条件下视觉器官所发生的变化研究报道尚属罕见。本研究应用组织学技术对胎兔在光照强度不同的条件下视觉器官所发生改变的实验结果，进行了分析，并证实在一定的光照强度及限定时间内胎兔视神经、视网膜等组织发育状况良好。本研究结果为进一步开展恍照胎教的理论学研究及早日应用于临床提供了     

The effect of the illumination time when treating port-wine stains

This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50m diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.     

Lightness, brightness and transparency: A quarter century of new ideas, captivating demonstrations and unrelenting controversy

The past quarter century has witnessed considerable advances in our understanding of Lightness (perceived reflectance), Brightness (perceived luminance) and perceived Transparency (LBT). This review poses eight major conceptual questions that have engaged researchers during this period, and considers to what extent they have been answered. The questions concern 1. the relationship between lightness, brightness and perceived non-uniform illumination, 2. the brain site for lightness and brightness perception, 3 the effects of context on lightness and brightness, 4. the relationship between brightness and contrast for simple patch-background stimuli, 5. brightness “filling-in”, 6. lightness anchoring, 7. the conditions for perceptual transparency, and 8. the perceptual representation of transparency. The discussion of progress on major conceptual questions inevitably requires an evaluation of which approaches to LBT are likely and which are unlikely to bear fruit in the long term, and which issues remain unresolved. It is concluded that the most promising developments in LBT are (a) models of brightness coding based on multi-scale filtering combined with contrast normalization, (b) the idea that the visual system decomposes the image into “layers” of reflectance, illumination and transparency, (c) that an understanding of image statistics is important to an understanding of lightness errors, (d) Whittle’s log W metric for contrast-brightness, (e) the idea that “filling-in” is mediated by low spatial frequencies rather than neural spreading, and (f) that there exist multiple cues for identifying non-uniform illumination and transparency. Unresolved issues include how relative lightness values are anchored to produce absolute lightness values, and the perceptual representation of transparency. Bridging the gap between multi-scale filtering and layer decomposition approaches to LBT is a major task for future research.     

瞳孔大小和瞳孔中心位移曲线随照明度变化的研究

背景准分子激光角膜屈光手术已成为矫治屈光不正的主要方式之一。术中切削中心的精确定位对术后视觉质量有重要影响。瞳孔中心位置的变化是影响切削中心定位的重要因素，因此有必要对其进行深入研究。目的研究不同照明条件下，人眼瞳孔中心随瞳孔大小改变发生位移过程中的动态规律，探讨瞳孔中心位移曲线的规律在准分子激光角膜屈光手术中的临床应用。方法在Astra Max3D角膜地形图测量系统基础上，对其照明亮度及图像拍摄模式进行自定义修改。利用该系统对57例114眼中度近视患者由照明亮度改变所产生的瞳孔大小和瞳孔中心位置的改变进行测量。照明亮度分为0．8、4．4、18．9、82．3、355．0lx5个光照度等级。使用向量和相对值分析的方法对瞳孔中心相对角膜共轴反光点的位置变化进行统计。不同光照度状态下瞳孔大小的相对变化幅度（AP）以占总变化幅度的百分数（最暗时瞳孔大小的变化设为0％，最亮时变化幅度为100％）表示；瞳孔中心的相对位移量（AC）以占总位移量的百分数（最暗时为0％，最亮时设为100％，以角膜中央顶点为原点）表示，并分析瞳孔中心在随光照度不同而发生变化过程中的位移曲线特点。结果5个光照度水平下瞳孔平均变化量分别为：0、（1．28±0．40）、（2．34±0．53）、（3．34±0．54）、（4．03±0．56）mm。AP分别为0％、32％、58％、83％、100％。随着光照度水平的增加，瞳孔由大变小时，瞳孔的中心位置由角膜顶点的颞侧向鼻侧发生位移。5个光照度情况下瞳孔中心平均位移量分别为：0、（78±33）、（116±60）、（143-±66）、（170±71）μm。AC分别为0％、46％、68％、84％、100％。AC与AP之间存在近似线性关系（r=0．980，P=0．025）；瞳孔中心位移的幅度和瞳孔大小变化幅度呈正相关（r=0．480，P〈0．01）。结论当光照度水平发生变化时，瞳孔中心位置随瞳孔大小变化发生一致性改变，可以用于指导个性化准分子激光角膜屈光手术切削中心的精确定位。     

Opposite effect of illumination and d-amphetamine upon activity in the squirrel monkey (Saimiri) and owl monkey (Aotes)

Summary The effect of d-amphetamine upon locomotor activity in the monkey is not uniform and seems related to the noctural-diurnal tendencies of the subject. It increases activity of the nocturnal subject and decreases the activity of the diurnal subject.This work was done while the authors were at Emory University and was supported by a research grant (MH 04539) from National Institute of Mental Health.     

Effects of amphetamine and illumination on activity following frontal ablation

Hyperactivity in the rat resulting from the removal of the frontal lobe, including the head of the caudate-putamen nucleus, in combination with d-amphetamine administration was studied in the light and dark over a 30 day postsurgical recovery period. Both d-amphetamine administration and frontal ablation increased activity level. In addition, d-amphetamine administration reversed the normal relationship of illumination with activity level. The postoperative hyperactivity following frontal ablation was dependent on the illumination level during testing. Potentiation of frontal induced hyperactivity by d-amphetamine was observed but the potentiation was not independent of the ambient illumination.     

Photic responses of suprachiasmatic area neurons in diurnal degus (Octodon degus) and nocturnal rats (Rattus norvegicus)

Photic sensitivity of cells in the suprachiasmatic nuclei (SCN), the principal pacemaker of the mammalian circadian system, has been documented in several species. In nocturnal rodents, the majority of photically responsive SCN cells are activated by retinal illumination. One report identified mostly photic suppressions among SCN cells in a diurnal rodent, studied under somewhat different conditions. We examined photic sensitivity of SCN cells in a predominantly diurnal rodent, the degu, studied in vivo under identical conditions to rats, and found that a large majority of photic SCN cells were suppressed by light. In both rats and degus, SCN cells were more responsive to light during the subjective night than during the subjective day. Light-responsive cells did not show a daily rhythm in baseline firing rates in either species, but rat SCN cells that did not respond to light were more active spontaneously during the subjective day. Light-unresponsive SCN cells in degus did not show a similar pattern. There are substantial differences in the neurophysiological activity and photic responsiveness of SCN cells in diurnal degus and nocturnal rats.     

基于照明反射模型的内窥镜图象增强方法研究

图象增强方法的研究主要集中于复杂的自适应算法的研究,并且较多地适用于Ｘ射线图片和ＣＴ影像,针对内窥镜图象的增强方法研究较少。本文首先分析医用电子内窥镜图象的主要特点,提出基于照明反射模型的同态滤波方法,接着在简要介绍模型的原理、实现过程和特点的基础上,给出了适用的滤波函数模型和表达式;最后,将处理结果和其它图象增强方法相对比。实验证明此方法可以更多地保留图象细节,更好地抑制高频噪声和图象亮度的白色     

Subtance P-immunoreactive innervation from the retina to the suprachiasmatic nucleus in the rat

The present study examined substance P (SP) innervation in the suprachiasmatic nucleus (SCN) of the rat. In the colchicine-untreated rat, SP-immunoreactive fibers formed a dense oval plexus in the ventral part of the SCN. After bilateral eye enucleation, there was a marked reduction in SP-immunoreactive fibers in the ventral part of the SCNs. The SP-immunoreactive neurons in the retinal ganglion cell layer were retrogradely labeled after injection of Fluoro-gold into the SCN. These findings indicate the presence of the SP innervation from the retina to the SCN in the rat. The role of SP in the retino-hypothalamic tract was discussed from the light-dark cycle.