bluuebunny/crossref_metadata_2025_split huggingface dataset:
Retinal neurotransmitters, morphology, and color coding
Authors: Marc Robert E. 
Published: June 2007

AbstractThrough the application of combined neurochemical and anatomical techniques it has been possible to assign putative neurotransmitter substances to several neuron classes in the goldfish retina. Rod photoreceptors appear to use glutamic acid or a close analog as their transmitter substance. Red‐sensitive and green‐sensitive cones appear to use some acidic amino acid or close analog, but neither aspartic nor glutamic acid appears to be a reasonable candidate. At present, blue‐sensitive cones have not been assigned a plausible neurotransmitter substance. Horizontal cells, known as type H1, use gamma‐aminobutyric acid (hereafter abbreviated GABA). A type of pyriform amacrine cell whose dendritic processes branch in the deepest part of the inner plexiform layer also uses GABA. A large population of small‐bodied amacrine cells with diffuse dendritic arbors branching in the middle of the inner plexiform layer utilize glycine. One type of indol‐amine‐accumulating amacrine cell is found to branch in the most superficial portion of the innerplexiform layer. Two classes of interplexiform cells have now been characterized: One employs dopamine and the other uses glycine. The majority of the retinal channels modulated by these conventional transmitter substances are dominated by red‐sensitive cone systems.
Human late‐receptor potential and its clinical use in dyschromatopsia
Authors: Kawasaki Kazuo , Yonemura Daizo , Tanabe Jhoji , Nakazato Hirohiko , Kawaguchi Izumi , Shirao Yutaka 
Published: June 2007

AbstractThe off response of the P III component isolated by aspartate in the human eyecup in vitro showed an initial rapid decay followed by a slow decay. The rapid decay in the human ERG originates mainly in cones. The rapid decay was also observed in human subjects. The spectral sensitivity curve of the rapid decay was found to be shifted toward short wavelengths in all nine protanopes tested. In these cases of protanopia, anomalous cone functions were indicated.
Spatial organization of retinal ganglion cells in turtle, Pseudemys
Authors: Granda A. M. , Fulbrook J. E. 
Published: June 2007

AbstractSingle‐unit receptive fields were investigated in retinal‐ganglion‐cell axons to moving or flashing colored‐light spots. All of the cells were sensitive to moving stimuli; about 40% were directionally selective. Retinal‐ganglion‐cell axons in general had very low spontaneous activities. Most receptive fields had silent surround regions. These cells were usually most sensitive to red light, but when dark‐adapted, many cells also showed a high sensitivity to green and blue light. Under conditions of light adaptation, receptive fields to red light were little affected but receptive fields to green and blue lights disappeared. Fields were either circular, oval, or bar‐shaped. Adaptation, wavelength, and velocity affected the receptive field organization and response profiles. The mutability and complexity of receptive field organization, the presence of bar‐shaped fields and directionally selective cells, and multiple photoreceptor input to ganglion cells are indicative of retinas with particularly high integrative capacities, more so than in many other vertebrates.
Chromatic properties of bipolar cells in the carp retina
Authors: Sakakibara Manabu , Mitarai Genyo 
Published: June 2007

AbstractIn order to analyze the receptive‐field arrangement of color‐opponent bipolar cells, the intracellular responses to monochromatic light spots of different sizes and shapes were recorded from the isolated retina of the carp (Cyprinus carpio) under photopic conditions. Out of 72 bipolar cells identified, 39 color‐opponent cells were classified into three types: the spatially segregated color‐opponent type, the surround color‐opponent type, and the center coloropponent type. The spectral responses of the second type in the surround receptive field were similar to those of their chromatic counterparts in the horizontal cells, suggesting a close relationship to the horizontal‐cell feedback mechanism. The third type was characterized by a small center area of less than 100 μm in diameter. For each type, the mirror images of the spectral response curves were obtained from on and off bipolar cells. This fact strongly suggests that the four basic color channels originate in the bipolar cells.
Additivity failure of chromatic valence in the opponent‐color theory
Authors: Ikeda Mitsuo , Ayama Miyoshi , Ohmi Masao 
Published: June 2007

AbstractThe additivity of flicker responses produced by two different wavelengths λ1and λ2was investigated for five adapting levels of 560 nm by the summation‐index method. A summation‐index value of σ of 0.30 was obtained for all conditions employed, confirming the linear property of the achromatic channel. The additivity of unique chromatic responses, red, yellow, green, and blue, was also investigated with the same method. In this case the wavelengths λ1and λ2were chosen in a spectral region to produce one of the four unique colors and the summation index was measured for the color with the cancellation method. A summation index of 0.30 was found for the green and blue sensations and also for the red sensation if both stimuli were from the same spectral region. A slight additivity failure of the enhancement type was found for pairs λ1and λ2λ1was in the short‐wavelength region while λ2was in the long‐wavelength region. An additivity failure of the same type was found for the yellow chromatic sensation when λ2was 607 nm and λ1was 570, 550, or 533 nm, the last combination giving a summation index of as much as 0.64. The results imply the existence of two different cones whose responses do not add linearly to yield the yellow sensation.
The neural organization of primate color vision
Authors: Gouras P. , Zrenner E. 
Published: June 2007

AbstractSome of the principal neurophysiological findings in primate retina are related to the postulated R–G, B–Y, and luminance channels of psychophysical color theory. The concept of on‐ and off‐center channels, weak and strong R–G opponency, tonic and phasic systems, and the curious asymmetry of the B–Y channel and its relationship to the detection of whiteness and blueness are stressed.
Remarks on filling the gap between studies of two different modes of appearance: Aperture color and object color
Authors: Indow Tarow 
Published: June 2007

AbstractWhat we perceive in daily life are predominantly object colors, and what the subject observes in psychophysical experiments with light stimuli are aperture colors. First, it is pointed out that interchangeability of psychophysical laws between the two modes of appearance has been explicitly or implicitly assumed in color science, and some uniform‐chromaticity diagrams and color‐difference formulas are defined on this assumption. Second, it is discussed whether saturation as a function of colorimetric purity is quantitatively the same in the two modes, and how to design a rigorous experimental test on the interchangeability.
Use of retroreflectors in the improvement of nighttime highway visibility
Authors: Woltman H. 
Published: June 2007

AbstractA half‐century ago retroreflective glass buttons were formally approved to improve the nighttime visibility of highway signs. The development of flexible retroreflective sheetings dates from the late 1930s, and these unique materials permitted the uniform color coding of warning, regulatory, and informational signs. Color coding has contributed to more rapid comprehension and the transmission of fairly complex information. The success of the signing system at night depends on sign brightness, size, and on the natural background against which the driver must see the sign. Research on signing materials is providing improved brightness, while greater understanding of our dependence on the nighttime environment is leading to attempts at characterizing this important variable. The subsequent adjustment of sign luminance will provide traffic signs that more satisfactorily match driver needs.
Color‐discrimination perimetry
Authors: Uchikawa Hiromi , Kaiser P. K. , Uchikawa Keiji 
Published: June 2007

AbstractColor‐discrimination perimetry was performed using Munsell color chips to determine how far from the fovea specific color differences would be just‐noticeably different. The results show that color‐discrimination limits were larger in the red‐to‐purple and the blue‐to‐green regions of the color circle than in the purple‐to‐blue, the green‐to‐yellow, and the yellow‐to‐red regions. Achromatic color‐discrimination limits went further into the periphery than did chromatic limits. We also performed color‐naming experiments at the fovea and in the periphery (30° nasal). Our results are reasonably well accounted for by the deuteranopic tendencies in the periphery of the retina.
Latent spaces of color preference with and without a context: Using the shape of an automobile as the context
Authors: Saito Takayuki 
Published: June 2007

AbstractThis article compares color preferences with a context to color preferences without it, using chips of 50 colors and the shape of an automobile as the context. Subjects were asked to make preference judgments of the color chips with the shape and also without it in the experiment. Multi‐ variate analyses were performed on the two sets of data to deriue latent spaces of color preference with and without the context. Through interpretation and comparison of the derived spaces, it was found that there was a noticeable context effect between the preference judgments.
Multidimensional mapping of 178 munsell colors
Authors: Indow Tarow , Aoki Nanako 
Published: June 2007

AbstractIn the right half of the Munsell color space from 2.5R to 7.5BG, 90 colors were selected, most of which were at the lightness level V = 7, and in the left half from 2.5BG to 7.5R, 88 colors were selected most of which were at the level V = 4. Of these 178 colors, 176 pairs in the right half and 185 pairs in the left half were subjected to the following color‐difference judgment. Subjects, five in number, selected two grays for which the lightness difference matches a given color difference in size. Two matrices (incomplete) of color differences given in terms of V were processed by MDSCAL, and finally one configuration of 178 points was synthesized in a three‐dimensional Euclidean space. Implications of the results are discussed in connection with results of previous similar studies which were based upon much smaller numbers of colors.
Errors in spectrophotometry and colorimetry of fluorescent samples caused by polarization of the measuring system
Authors: Minato Hideyuki , Nanjo MotoL , Nayatani Yoshinobu 
Published: June 2007

AbstractThis article describes a method for the prediction of the reflected and the fluorescent spectral radiance factor which are expected to be measured by use of a measuring system with polarizing properties, and a method for the estimation of the spectrophotometric errors in the predicted radiance factors. Polarization properties are described for the measuring system, the white standard surface, and the two kinds of fluorescent samples used in the two‐monochromator method of the present study. In this method, the spectrophotometric errors in the reflected spectral radiance factor are estimated to be not less than 1% at some wavelengths. However, the error of the fluorescent spectral radiance factor is relatively small. Colorimetric errors of fluorescent samples due to polarization are estimated for the one‐ and two‐monochromator methods. The errors expressed as CIELUV color differences are estimated to be less than 1.0 unit and are negligibly small.
Luminance and saturation of equally bright colors
Authors: Uchikawa Keiji , Uchikawa Hiromi , Kaiser P. K. 
Published: June 2007

AbstractLuminances and saturations of equally bright colors were measured by heterochromatic flicker photometry and a saturation scaling method, respectively. We used 19 dominant wavelengths from 410 to 670 nm and in the purple region, and II excitation purities from 0.0 to 1.0 in 0.I steps for each dominant wavelength, as test stimulus colors. The results show that the luminances of equally bright colors with the same dominant wavelength decrease approximately linearly as the saturation estimates increase for all dominant wavelengths, but the slope of this lumi‐nance‐versus‐satuiation function varies with dominant wavelength. It is implied that the chromatic content of colors differentially contributes to the brightness‐luminance discrepancy depending on the dominant wavelength. We also plotted constant‐luminance loci and constant‐saturation loci in the 1931 CIE x, y and the 19.76 CIE‐u', v' ‐chromaticity diagrams.
The basic concepts and attributes of colour order systems
Authors: Wright W. D. 
Published: June 2007

AbstractOne of the first—if not the first—colour order system described in the literature is that of the Swedish scientist Forsius in his book Physica, published in 1611, and the Symposium at which this article was presented was organised to provide a forum for discussion of the philosophy and principles underlying the various colour order systems that have been developed since that time. Two main types of colour order system can be identified, depending on the subjective variables of colour appearance on which they are based. These variables are discussed in this article with particular reference to the Munsell System and the Natural Colour System, the chief representatives of the two types of system, together with some comments on colour naming as an additional method of colour ordering. Here the Kelly‐Judd report on Color: Universal Language and Dictionary of Names (1976) provides a penetrating insight into the subjective terminology by which one block of colour space can be distinguished from another. Some other novel colour order systems are also mentioned.
Chromaticity‐discrimination ellipses for surface colours
Authors: Luo M. R. , Rigg B. 
Published: June 2007

AbstractAvailable colour‐discrimination data for surface colours have been analysed to produce chromaticity‐discrimination ellipses for individual colour centres. Applying simulated errors showed that when the distribution of samples around a standard was unsatisfactory, the ellipses obtained were unreliable. A total of 132 reliable ellipses were obtained. The values of 6 and a/b varied systematically over the chro‐maticity diagram, the patterns from acceptability, perceptibility, textile, and non‐textile ellipses being very similar. New experimental data involving over 400 pairs of samples corresponding to 70 of the colour centres and assessed against a grey scale were used to adjust the relative sizes of the ellipses. Overall set factors were used to bring data from different sources onto a common scale. However, even after allowing for different lightness levels, the sizes of the ellipses still appeared to be irregular. Using the new results to adjust the sizes of the individual ellipses from any one group of data, e.g., BFD, DF, or MMB, gave ellipses forming a much more regular pattern. In contrast to the MacAdam ellipses, the smallest ellipses occurred in the blue‐grey region. Our results imply that the relative sizes of the ellipses from the same group of data are in error by a factor of two or more. Comparing colour differences for different colours appears to be much more difficult than has been previously realised. The problem appears to have affected all the major groups of published data.
Philosophy of perceptive color order systems
Authors: Tonnquist Gunnar 
Published: June 2007

AbstractA color order system may arrange color perceptions, color stimuli, or material color samples according to certain rules. Material color systems have many practical applications but are different for different materials and different applications. Stimulus systems are useful in comparing instrumental measurements of transmitted or reflected radiation, but do not adequately describe the appearance of the color perceptions. In most perceptive color systems attributes like hue, saturation, and lightness (or their near correlates) describe three‐dimensional color space. There are two main exceptions: the OSA–UCS system intended to be equidistant in all directions of color space, and the NCS, which is a Hering‐type opponent system, based on six innate elementary colors with six corresponding attributes. In the NCS, hue and chromaticness, which in other systems are primary attributes, are derived from the elementary attributes.
Transformation of NCS data into CIELAB colour space
Authors: Derefeldt Gunilla , Sahlin Christer 
Published: June 2007

AbstractThe data for the Natural Colour System (NCS) were transformed to the CIE 1976 (L*, a*, b*) system (CIELAB). The transformation involved taking the CIE tristimulus values of the nominal NCS notations, i.e., the colorimetric aim points representing the NCS, converting these values to CIELAB, and plotting them in the CIELAB space. All the data have been calculated using CIE standard illuminant C and the 1931 standard observer. The data show that no simple relationship exists between the NCS and CIELAB systems.
Distinctness of border: An alternative concept for a uniform color space
Authors: Hara Anders , Sivik Lars 
Published: June 2007

AbstractIn phenomenological analyses of the visual color gestalt it has been found that color plays at least a double role from a cognitive point of view. First, the characteristics of the color gestalt have to do with how man identifies colors, and are related to emotions, connotations, semantics, and symbolism. The NCS (Natural Color System) was designed to cover the need for a descriptive color order system, based on the six characteristic elementary color attributes whiteness, blackness, yellowness, redness, blueness, and greenness, from which was derived the three‐dimensional NCS color space for providing color notations. Second, the form of background and patterns in a color gestalt has to do with how man distinguishes color elements from each other by contrast and is informative about form and directions. In this article we report about one of the contrast phenomena, border distinctness between adjacent colors, which is most essential for the perception of form gestalts. Several years of phenomenological analyses and psychometric and psychophysical experiments have resulted in an equation for the prediction of the kind of contrast defined as border distinctness, called GT from the Swedish word Gränstydlighet. Based on that equation is a geometrical model for the GT color‐difference space that is not Euclidean but of city‐block type. The studies have led to the question of whether the phenomenon of color contrast (difference) is a perception of its own and not linearly related to the difference between two color perceptions.
Chromatic adaptation and color constancy: A possible dichotomy
Authors: Brill Michael H. , West Gerhard 
Published: June 2007

AbstractDifferences between chromatic adaptation and color constancy are discussed, in order to call into question the commonly held view that chromatic adaptation is the mechanism of color constancy. Whereas chromatic adaptation requires many seconds of time and occurs for simple visual scenes, color constancy asserts itself immediately and is most powerful in complex visual scenes. Furthermore, models of chromatic adaptation are not so illuminant invariant as other models of color vision. Therefore, a new operational foundation for color constancy is proposed, and existing non‐adaptation models of color constancy are enumerated for future tests.
Changes in constant‐hue loci with spatial frequency
Authors: Elsner A. E. , Burns S. A. , Pokorny J. 
Published: June 2007

AbstractWe examined the effects of spatial frequency and colorimetric purity using a hue‐matching technique. At constant retinal illuminance, hue matches of alternate stripes of square‐wave gratings changed with spatial frequency. At high spatial frequencies the data did not tend towards tritanopic confusion loci. Several alternative hypotheses, including optical factors, chromatic induction, and changes in the relative sensitivity of the opponent‐colors channels, are discussed. None of these mechanisms can explain all of the data.
In Silico Engineering of Tailored Ink‐Binding Ability at Molecular Printboards
Authors: Thompson Damien 
Published: June 2007

AbstractMolecular recognition between guest ink molecules and β‐cyclodextrin (β‐CD) cavities at self‐assembled monolayers provides a molecular printboard for nanopatterning applications. We recently used molecular dynamics (MD) simulations to describe the specificity of ink–printboard binding and here extend the simulations to include charged cyclodextrin hosts, necessary to broaden the chemistry of molecular printboards and bind charged inks such as the ferrocenium cation. Shifting to high pH, or alternatively grafting a charged sidearm onto β‐CD, created three distinct types of anionic β‐CD cavity and we used electronic structure calculations and MD simulations to measure host–guest charge transfer and binding strengths. We find that steric recognition of uncharged organic molecules is retained at the charged printboards, and that improved guest–host electrostatic contacts can strengthen binding of larger inks while penalising small inks, enhancing the level of discrimination. A prudent choice of complementary host–guest shape and charge states thus provides a means of tuning both ink binding strength and specificity at molecular printboards.
Synthesis, growth and characterization of L‐histidinium acetate dihydrate single crystals
Authors: Mathivanan V. , Raghavalu T. , Kovendhan M. , Gokul Raj S. , Ramesh Kumar G. , Mohan R. , Suriya Kumar K. 
Published: June 2007

AbstractL‐histidinium acetate dihydrate {abbreviated as LHAc; [C6H10 N3O2+ C2H3O2‐ 2H2O], a new nonlinear optical (NLO) material has been grown from aqueous solution. The grown crystals were subjected to X‐ray diffraction, Fourier transform infrared (FTIR) and FT‐Raman analyses. Thermal studies have been carried out for its thermal stability. Optical behaviour such as UV‐Vis‐NIR spectrum and second harmonic generation (SHG) were also investigated. Its SHG efficiency was found as deff = 2.2 deff (KDP). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PSSS‐controlled synthesis of CaCO3 superstructures
Authors: Tang Hua , Yu Jaguo , Ng Dickon H. L. 
Published: June 2007

AbstractComplex CaCO3 superstructure can be easily synthesized by using poly (sodium 4‐styrenesulfonate) (PSSS) as a structure directing agent to direct the controlled precipitation of calcium carbonate from aqueous solution. The products were characterized by scanning electron microscopy (SEM), and powder X‐ray diffraction (XRD) analysis. The results revealed that the morphology of the products changed significantly with the increasing of the concentration of PSSS in solution, from rhombohedral particles to plate‐packed aggregates to spheres with smooth surface, to sponge‐like spheres and finally to complex spherical superstructure consisted of plate‐like sub‐units. We hypothesize that the observed sequential changes in morphology of CaCO3 particles with added PSSS concentration may be due to the influence of PSSS on nucleation, growth and aggregation of CaCO3 crystals. The formation mechanisms of CaCO3 crystals with different morphologies were discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)