北京萤火虫复眼的模型小眼设计与光线追迹

以实际的北京萤火虫复眼结构与生理参数与依据,基于已知的ＧＲＩＮ透镜特征,把小眼的整个光学系统分成几个部分被模型化。模型中,在晶体柱部分使用了一个径向梯度折射率透镜柱具有的抛物线轮廓折射率公式;在晶锥末端所接的半椭球ＧＲＩＮ透镜部分,使用了一个径向梯度和纵向梯度分布都存在的折射率公式．模型的尺寸与折射率的大小根据实际晶锥的测量值．通过对模型小眼的光线追迹,证明模型小眼基本上是一个平行光入射,年行光出射的望远镜系统．小眼光学系统的前半部分把入射的平行光束聚焦到中间焦点,而这个点的位置恰好位于实际晶锥的腰的部位,而光线再次经过晶锥近端以后又以大致平行光束从晶锥末端出射。此模型小眼的最大入射角为３０度,在这个入射角内其角放大率基本上是相同的。随着对平行入射光束与小眼光轴的角度的增加,所产生的中间像越来越远离晶锥光轴。     

An Integrated Multistage Nanofocusing System

We demonstrate an integrated multistage nanofocusing system which combines a conventional objective, a surface plasmonic lens, and a center-positioned rounded-tip cone nanoparticle. The surface plasmonic lens, fabricated on the cover glass which has been mounted on the biological microscopic objective, is composed of several concentric annular slits for exciting propagating surface plasmonic wave. The rounded-tip cone nanoparticle is for further generating non-propagating localized surface plasmonic wave. It is revealed that the enhancement of the nanoscale optical field can be improved by carefully choosing the appropriate numerical aperture of the objective to match the specific nanostructure of the surface plasmonic lens and choosing the relatively big cone angle of the nanoparticle. The investigation shows that a highly confined electric field as small as 20 nm and an enhancement factor of 5 orders of magnitude can be achieved through this multistage nanofocusing system when the system is illuminated with a uniform radially polarized beam.     

大草蛉成虫复眼的外部形态及其显微结构

用扫描电镜和光学显微镜观察了大草蛉Chrysopa pallens Ramber成虫复眼的外部形态及明、暗适应和性别对其显微结构的影响。结果发现：（1）其复眼呈半球形,位于头部两侧,略成“八”字形排列,单个复眼约由3 600个小眼组成,最前和最后小眼之间的夹角约为180°,最上和最下小眼之间的夹角约200°;（2）小眼主要由角膜、晶锥和6～8个小网膜细胞、基膜组成,外围环绕有2个初级虹膜色素细胞和6个次级虹膜色素细胞,基膜处有色素颗粒分布;（3）暗适应时,晶锥开裂程度较大,远端5～7个网膜细胞核向远端移动,与晶锥近端相接或接近,次级虹膜色素颗粒亦向远端移动包围晶锥;明适应时,晶锥开裂程度小或闭合,远端网膜细胞核向近端移动,透明带显现,大部分次级虹膜色素颗粒亦向近端移动分布在小网膜细胞柱周围,包被透明带;（4）在相同的明、暗适应下,雌、雄成虫复眼的显微结构无明显差异。结果表明大草蛉复眼为透明带明显的重叠象眼,其小眼不但具有次级虹膜色素颗粒纵向移动的常规调光机制,还存在晶锥开闭、远端网膜细胞核移动和基膜色素颗粒纵向扩散的调光新机制。     

Ultrastructure of the eye of Urastoma cyprinae (Turbellaria,Alloeocoela)

Summary Urastoma cyprinae (Graff) is a microturbellarian which has been recorded both as a free-living organism by Westblad (1955) and Marcus (1951) and as a commensal in various lamellibranch molluscs (see Burt & Drinnan 1968). The material used in this study came from oysters, Crassostroea virginica, collected off the coast of Prince Edward Island, in which hosts it occurs in large numbers especially during the summer months when the oysters are spawning (Fleming et al. 1981). When U. cyprinae is exposed to light as happens, for example, when an oyster is opened, it shows a marked negative phototactic response.Preliminary work on the fine structure of the photoreceptors in U. cyprinae shows that the two eyes each consists of: (1) a single cup cell full of relatively large, electron-dense pigment granules; (2) a tripartite conical lens system; and (3) what appear to be two photosensitive rhabdomes. The pigment cup cell has a single, well defined nucleus situated basally and close to the membrane of the pigment cell furthest away from the rhabdomeres. The lens system consists of a cone made up of three, separate but equal, parts. Each part has two, flat inner surfaces which join at an angle of 120°, an outer rounded surface, and a rounded upper surface. When these three parts fit together, the cone-shaped lens is formed with the apex of the lens within the cup of the pigment cell and the rounded, convex, broad end of the cone lying more or less at the same level as the top of the pigment cup and below the epidermis layer. The rhabdomeres lie between the electron dense lenses and the inside of the pigment cup. They show connections to the visual cells which are bipolar: one extension joining the rhabdomeres; the other constituting the axon which extends into the centrally situated brain or into the longitudinal, lateral nerves. The axons that enter the brain, form connections with other axons from the other eye. The axons that extend posteriorly in a lateral position, presumably play a role in facilitating the avoidance reaction.The chemical nature of the unusual lens has not yet been determined. This is presently under investigation and will be reported later at which time our work will be discussed in relation to other types of rhabdomeric eyes in the Turbellaria.     

Lens optical properties in the eyes of large marine predatory teleosts

The optical properties of the crystalline lenses were studied in a variety of large predatory teleosts (bony fishes) that forage in the open ocean, some of them at considerable depths. We found the first fish lenses that are free of measurable longitudinal spherical aberration, i.e., are perfectly monofocal, in contrast to the multifocal lenses that are typical for smaller fishes living close to the surface. In fact, none of the lenses investigated in this study were clearly multifocal. Most, but not all, of the lenses had long normalized focal lengths (focal length/lens radius) of up to 3.3 lens radii. A monofocal lens of long focal length, combined with spectrally suitably placed cone pigments, may be the optimal solution for vision of high spatial and spectral resolutions in a habitat where the available spectrum of light is limited.     

Ocular dimensions and cone photoreceptor topography in adult Nile Tilapia <Emphasis Type="Italic">Oreochromis niloticus</Emphasis>

Information on the anatomy of the eye and the topography of cone photoreceptor cells in the retina is presented for the Nile Tilapia (Oreochromis niloticus). In adults, the shape and proportions of the ocular components of the prominent eye conform to the general form of fish eyes, as determined using cryo-sectioned eyes. The lens is approximately spherical and there is little variation in the distance from the centre of the lens to the border between the choroid and retina at a range of angles about the optical axis. The average ratio of the distance from the centre of the lens to the retina: lens radius (Matthiessen’s ratio) is 2.44:1. In retinal wholemounts, single and double (twin) cone photoreceptors, forming a square mosaic, are present. Peak photoreceptor densities for both morphological cone types are found in the temporal retina. Using peak cone densities and estimates of focal length from cryo-sectioned eyes, visual acuity is calculated to be 5.44 cycles per deg. The lack of apparent specific ocular or retinal specializations and the relatively low visual acuity reflect the lifestyle of the Nile Tilapia and may allow it to adapt to changes in visual environment in its highly variable natural habitat as well as contributing to the ‘ecological flexibility’ of this species.     

Cone photoreceptor mechanisms and the detection of polarized light in fish

Summary Although numerous studies have demonstrated the detection of polarized light in vertebrates, little is known of the photoreceptor mechanisms involved. Recent evidence, however, indicates that cyprinid fishes possess both ultraviolet (UV) and polarization sensitivity suggesting that some vertebrates, like many invertebrates, may employ UV-sensitive cone receptors in polarization sensitivity. In this report, we describe experiments that determine which spectral types of receptors participate in the detection of polarized light. We used a heart-rate conditioning technique to measure increment thresholds of immobilized goldfish for plane-polarized, narrow-band (10 nm half max.) spectral stimuli (380 nm, 460 nm, 540 nm, 660 nm). A typical experiment involved isolating the activity of a cone photoreceptor mechanism by chromatic adaptation and measuring increment thresholds for spectral stimuli at e-vector orientations of the polarizer between 0° to 180° in 30° steps. The UV-, green- and red-sensitive cone receptor mechanisms showed clear evidence of polarization sensitivity while the blue-sensitive cone receptor mechanism was polarizationally insensitive. The average amplitude (base to peak height on Fig. 4) of the polarization sensitivity curves (UV-, green- and red-curves) was 0.67 log unit (standard deviation of 0.12 log unit), with the UV-sensitive cone receptor mechanism most sensitive to the vertical e-vector axis and the green- and red-sensitive cone receptor mechanisms most sensitive to the horizontal e-vector axis. The observation that different cone photoreceptor mechanisms have orthogonal polarization sensitivity in fish suggests that the perception of polarized light may enhance the capacity for visual discrimination in lower vertebrates.     

Optical evaluation of red blood cell geometry using micropipette aspiration.

Although red blood cell (RBC) geometry has been extensively studied by micropipette aspiration, the small size of RBC and pipettes vs. the optical resolution of light microscopy suggests the need to consider potential errors. The present study addressed such difficulties and investigated four specific problems: (1) use of exact equations to calculate RBC membrane area and volume; (2) calibration of the pipette internal diameter (PID); (3) correction for a noncylindrical pipette barrel; (4) diffraction distortion of the RBC image. The observed PID represents a cylinder lens enlargement that can be theoretically derived from the glass/buffer refractive index ratio (1.49/1.33 = 1.12). This enlargement was experimentally confirmed by: (1) studying pipettes bent to allow measurement through the barrel (horizontal) and at the orifice (vertical), with a resulting diameter ratio of 1.12 +/- 0.01; (2) and by replacing the surrounding buffer with immersion oil and hence abolishing the lens phenomenon (ratio = 1.12 +/- 0.02). In addition, use of aspirated oil droplets demonstrated a 3.2 +/- 0.2% error when the PID is focused at a sharp, maximum diameter. The average pipette cone angle was 1.49 +/- 0.09 degrees and varied considerably with pipette pulling procedures; calculated tongue geometry inside the pipette was affected by the noncylindrical pipette barrel. The RBC diffraction error, demonstrated by touching two aspirated cells held by opposing pipettes, was 0.091 +/- 0.002 microns. The PID, cone angle, and diffraction artifacts significantly (p < 0.001) affected calculated RBC geometry (average errors up to 5.4% for area and 9.6% for volume). Two new methods to calculate, rather than directly measure, the PID from images of a single RBC, during either osmotic or pressure manipulation, were evaluated; the osmotic method closely predicted the PID, whereas the pressure method markedly underestimated the PID. Our results thus confirm the need to consider the above-mentioned phenomena when determining RBC geometric parameters via micropipette aspiration.     

Structure and functional aspects of the scotopic compound eye of the sugarcane borer moth

Morphology and functional aspects of the scotopic compound eye of the moth Diatraea saccharalis, studied using light and electron microscopy, is presented. An ommatidium is composed of a laminate corneal lens, four Semper cells, a refractive cone, two primary pigment cells, six screening pigment cells, a crystalline tract that functions as an optical waveguide, and six to eight sensory retinular cells. Accessory light regulators consist of screening pigment cells that, in the dark-adapted position, increase receptor sensitivity by permitting light rays to cross over to adjacent ommatidia and specialized tracheal regions that enhance sensitivity by reflecting light back toward sensory receptors.     

Design of a Trichromatic Cone Array

Cones with peak sensitivity to light at long (L), medium (M) and short (S) wavelengths are unequal in number on the human retina: S cones are rare (<10%) while increasing in fraction from center to periphery, and the L/M cone proportions are highly variable between individuals. What optical properties of the eye, and statistical properties of natural scenes, might drive this organization? We found that the spatial-chromatic structure of natural scenes was largely symmetric between the L, M and S sensitivity bands. Given this symmetry, short wavelength attenuation by ocular media gave L/M cones a modest signal-to-noise advantage, which was amplified, especially in the denser central retina, by long-wavelength accommodation of the lens. Meanwhile, total information represented by the cone mosaic remained relatively insensitive to L/M proportions. Thus, the observed cone array design along with a long-wavelength accommodated lens provides a selective advantage: it is maximally informative.     

Eye Structure and Vision in the Freshwater Pulmonate Mollusc Planorbarius corneus

The structure of the mollusc Planorbarius corneus eye was studied using light and electron microscopy. The eye consists of the cornea, eye lens of non-spherical shape, and the vitreous body tightly bound to it, as well as of a monolayer non-inverted retina composed of photoreceptor and supporting (pigmented) cells. Its inner surface has two invaginations. The apices of several hundreds of photoreceptors directed to the vitreous body have groups of microvilli with a parallel orientation to each other. The eye optic system places the image into the base of the retinal microvillar layer. Its angle resolution provided by density of distribution of photoreceptor cells and the value of the index F = 1.71 is to be about 2.06° with a correction for the light spreading between microvilli of neighbor cells. Under conditions of a V-shaped labyrinth, the P. corneus molluscs show positive phototaxis by moving to the light source. The angular acuity of vision was assessed from differences in the choice by the molluscs of direction of movement to the pattern of vertical black bands with different periods of alternation. The differential threshold obtained is within an interval of 1.43–1.91°, which is close to the calculated value of angular resolution of the retina.     

A cellular basis for polarized-light vision in rainbow trout

Polarized light sensitivity was examined in single units of the rainbow trout (Oncorhynchus mykiss) torus semicircularis, a sub-tectal visual area with a high degree of ultraviolet sensitivity. First, chromatically isolated torus units with inputs from each of the four cone mechanisms found in the trout visual system were separately examined for e-vector sensitivity. UV ON-response units showed polarization sensitivity for vertical ly (0° and 180°) polarized stimuli, while ON-response units of the short, middle and long cone mechanisms were not polarization sensitive. No OFF-response units of the UV or short cone mechanism were observed, but OFF-response units of the middle and long cone mechanisms show polarization sensitivity for horizontally (90°) polarized stimuli. Second, e-vector sensitivity was observed in color-coded units which received inputs from more than one cone mechanism and showed different sign responses (ON or OFF) at different points of the spectral sensitivity curve. Biphasic units which had ON input from the UV cone mechanism and OFF inputs from the middle and long cone mechanisms showed polarization opponency. This opponency was observed with a 380 nm stimulus when the threshold sensitivities of the alpha-band absorption peak of the UV mechanism and the beta-band absorption peak of the middle and long cone mechanisms were equal. We believe that biphasic torus units provide a possible cellular basis for polarized light vision in rainbow trout.Abbreviations UV ultraviolet - S short - M middle - L long - PS polarization sensitivity - TS torus semicircularis - ONR optic nerve response     

灰茶尺蠖成虫复眼的超微结构及其明暗适应中的变化

【目的】明确灰茶尺蠖Ectropis grisescens成虫复眼的超微结构及其明暗适应中的变化,探究其调光机制。【方法】采用超景深显微镜测定了灰茶尺蠖成虫复眼的小眼数量、间角、直径和曲率半径等外部参数,并通过组织切片、光学显微镜和透射电子显微镜等技术观察了复眼的内部超微结构;通过光学显微镜观察了灰茶尺蠖成虫复眼在明暗环境中分别适应2 h后晶锥结构及色素颗粒的位置变化。【结果】灰茶尺蠖成虫复眼呈半球形,雌、雄虫单个复眼分别有2 502±105和3 123±78个小眼。小眼自远端至近端由角膜、晶锥、透明区构成的屈光层和由15个视网膜细胞构成的感光层组成。2个初级色素细胞包裹着晶锥,自角膜近端延伸至视网膜细胞核区的远端;每个小眼外围由6个次级色素细胞围绕,自角膜近端延伸至基膜;在透明区内14个视网膜细胞聚集成束(非感杆束),远端与晶锥束末端连接,在感光层内形成闭合型感杆束,延伸至第15个视网膜细胞(基部视网膜细胞)。在明暗适应时,灰茶尺蠖复眼的晶锥细胞间出现开闭,色素颗粒进行纵向位移,以适应外界的光强度的变化。【结论】灰茶尺蠖成虫复眼属于重叠像眼,感杆束为“14+1”模式;屏蔽色素颗粒的移...     

Catalytic properties of water-soluble rhodium and iridium complexes: the influence of the ligand structure

Rhodium and iridium complexes of trisulfonated triarylphosphanes, TPPTS (tris(3-sulfonatophenyl)phosphane), T(p-A)PTS (tris(3-sulfonato-4-methoxyphenyl)phosphane), T(2,4-X)TS (tris(2,4-dimethyl-5-sulfonatophenyl)phosphane), have been tested in biphasic hydrogenation of aldehydes. T(2,4-X)TS could not stabilize the rhodium complex under the applied conditions. Guanidium salt of T(2,4-X)TS has been characterized by X-ray crystallography, and Tolman cone angle of the phosphane has been determined from crystallographic data. The large cone angle (196°, 210°) explains the instability of the rhodium complex. Contrary to the T(2,4-X)TS/rhodium system, the T(2,4-X)TS/iridium catalyst has been found to be stable and effective in hydrogenation of benzaldehyde and caproaldehyde.     

Kinetics of reactions of Os6(CO)18 with some P-donor nucleophiles: Some unusual isokinetic relationships

The cluster Os₆(CO)₁₈ with its bi-capped tetrahedral Os₆ core reacts with some P-donor nucleophiles in toluene via associative paths, but the range of P-donors that can react at convenient rates for kinetic study is limited by the exceptional dependence of the rates on the basicity and size of the nucleophiles. The observed linear free energy relationship (LFER), shown by the small set of accessible data is accompanied by the existence of an isokinetic temperature of 89.5 ± 3.5 °C that controls the effect of nucleophiles basicity. This isokinetic behaviour is known to be an inevitable logical consequence of the existence of the LFERs at different temperatures but other necessary isokinetic properties are also demonstrated to exist. These are an isokinetic basicity (IKB) parameter, which results in the predicted temperature independence of rates of reaction with nucleophiles of a certain basicity, and an isokinetic cone angle parameter (IKCA) that is predicted to result in the temperature independence of the rates at a certain nucleophile cone angle.     

Species dependence of the zero-stress state of aorta: pig versus rat.

The zero-stress state of an aorta can be characterized by the angle with which each segment of the vessel opens up when it is cut radially. The opening angle varies with the region of the aorta: significantly with respect to the axial location, less significantly with respect to polar angle of the radial cut. Both pig and rat aortas have large opening angles in the neighborhood of 130 deg in the aortic arch region. In the thoracic region, the species difference is evident. The opening angle of the pig aorta in the middle thoracic region is rather constant in the neighborhood of 60 deg. The opening angle of the rat aorta in the thoracic region varies considerably, decreasing to 10 deg at the lower end of the thoracic region. In the abdominal region the opening angle of the pig increases from 60 to about 80 deg, that of the rat increases from about 10 to 90 deg. The potassium ion has effect on vascular smooth muscle, but has little effect on the opening angle. This suggests that the opening angle is not sensitive to smooth muscle contraction, similar to a previously known result that the opening angle is not affected by papaverine. The vessel wall thickness and vessel diameter were measured. It is shown that the ratio of the wall thickness to diameter of the pig is considerably larger than that of the rat throughout the aorta.(ABSTRACT TRUNCATED AT 250 WORDS)     

昆虫重叠型复眼的光学综合成象特性

本文计算了复眼锥形晶体柱端面凸球对输入数值孔径的作用,讨论了昆虫重叠型复眼的非相干综合成象特性.     

On a probabilistic model for the numerical estimation of nocturnal migration of birds

The study of nocturnal bird migration by cone methods of observation has a century-long history but has continued to be used up to the present. To describe the flux and estimate the number of passing birds a probabilistic model is proposed. This model is based on the concept of dynamic Poisson ensemble of points in appropriate phase space and has two parameters. One is scalar and the other one is functional. We constructed consistent estimations of these parameters and discuss their use for the numerical estimation of the flux of birds observed in a narrow light cone generated by the bright lunar disk and formed by an open angle of telescope. Selection on the same type of birds was suggested as the necessary condition for the model application. Ground speed of each bird was introduced into the model as a new but obligatory value determining the quantification of the flux of bird.     

Interference reflection microscopy. A quantitative theory for image interpretation and its application to cell-substratum separation measurement.

We propose a quantitative theory of microscope interferometry where the specimen is illuminated by a cone of monochromatic light of solid angle 0 - 100 degree, corresponding to an illuminating numerical aperture of 0 to approximately 1.2. Computed results compare favorably with photometric measurements of fringe irradiance for a water wedge 0 - 2,000-nm thick. The interpretation of cell-substratum interference images is discussed in relation to the theory. We conclude that in assessing cell-glass separation, the cytoplasmic thickness does in general contribute significantly to the final image, but this contribution is minimized at high illuminating apertures. In these circumstances, however, normal incidence theory is inapplicable and the theory for finite illuminating aperture is essential. Neglect of this fact can lead to errors of up to 100% in estimated cell-glass separation.     

The Lens Circulation

The lens is the largest organ in the body that lacks a vasculature. The reason is simple: blood vessels scatter and absorb light while the physiological role of the lens is to be transparent so it can assist the cornea in focusing light on the retina. We hypothesize this lack of blood supply has led the lens to evolve an internal circulation of ions that is coupled to fluid movement, thus creating an internal micro-circulatory system, which makes up for the lack of vasculature. This review covers the membrane transport systems that are believed to generate and direct this internal circulatory system.