Chromatic stability of acrylic resins of artificial eyes submitted to accelerated aging and polishing

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Why are fruits colorful? The relative importance of achromatic and chromatic contrasts for detection by birds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromatic alteration in Arenaeus cribrarius (Lamarck) (Crustacea, Portunidae): an indicator of sexual maturity

Some individuals of the species Arenaeus cribrarius (Lamarck, 1818) bear a characteristic pink abdomen, which is notably different from the usual white coloration. The incidence of this chromatic alteration was determined for a single population and its relation with other individual variables were examined. The individuals were monthly collected from May, 1991 to April, 1993, in Ubatuba, São Paulo, with the aid of a shrimp fishery boat provided with double-rig trawling nets. All specimens were sexed, measured (CW = carapace width), distributed in 10-mm size classes and classified according to growth phase (juvenile and adult), molting condition and development stage of gonads. The occurrence of pink-colored morphs was also recorded. From a total of 2,096 collected individuals, only 60 females (nine of those ovigerous) presented a pink-colored abdomen, which represents 2.9% of the whole sample and 5.2% of the females. Almost all of them were intermolt individuals (96.6%) and 63.3% showed mature gonads. According to published data, size at the onset of functional maturity in A. cribrarius females is around 60 mm CW, from which the incidence of pink morphs and ovigerous crabs were recorded. The obtained results suggest that such a chromatic alteration is associated to sexual maturity in these females. This characteristic may enhance the attraction potential for mating, shortly after the puberty molt.

Chromatic characteristics and color-related phenolic composition of Brazilian young red wines made from the hybrid grape cultivar BRS Violeta (BRS Rúbea×IAC 1398-21)

The color characteristics and the phenolic composition related to color of young red wines elaborated with the hybrid grape cultivar BRS Violeta, developed for its adaptation to sub-tropical climates in Brazil, have been studied. These wines are characterized with a deep red-purplish color, reaching color intensity averaging 24 units. In spite of being young red wines elaborated with short maceration time, their content in total polyphenols was very high (around 3692. mg/L, as gallic acid equivalents), especially when compared to similar Vitis vinifera young red wines. Within polyphenols, anthocyanins predominated (around 2037. mg/L, as malvidin 3,5-diglucoside equivalents) and they were almost exclusively anthocyanidin 3,5-glucosides (ca. 97%), mainly built from B-ring tri-substituted anthocyanidins (delphinidin. >. petunidin. ≈. malvidin) and having high proportion of p-coumaroylated derivatives (ca. 28%) that confer higher stability. The content of hydroxycinnamic acid derivatives was also remarkable (ca. 95. mg/L, as caffeic acid equivalents) and unknown glucose derivatives of p-coumaric acid accounted for ca. 42% of total HCAD. Finally, these found flavonols were mainly based on myricetin whereas kaempferol derivatives were missing, their total content being within the ranges usually found for V. vinifera wines, but reaching their top values (ca. 91. mg/L, as quercetin 3-glucoside equivalents). All the aforementioned data suggest that Violeta wine could be considered an important dietary source of healthy polyphenols with a moderate alcoholic content (ca. 11.6%). © 2013 Elsevier Ltd.

Chromatic spatial contrast sensitivity estimated by visual evoked cortical potential and psychophysics

The purpose of the present study was to measure contrast sensitivity to equiluminant gratings using steady-state visual evoked cortical potential (ssVECP) and psychophysics. Six healthy volunteers were evaluated with ssVECPs and psychophysics. The visual stimuli were red-green or blue-yellow horizontal sinusoidal gratings, 5^° × 5^°, 34.3 cd/m2 mean luminance, presented at 6 Hz. Eight spatial frequencies from 0.2 to 8 cpd were used, each presented at 8 contrast levels. Contrast threshold was obtained by extrapolating second harmonic amplitude values to zero. Psychophysical contrast thresholds were measured using stimuli at 6 Hz and static presentation. Contrast sensitivity was calculated as the inverse function of the pooled cone contrast threshold. ssVECP and both psychophysical contrast sensitivity functions (CSFs) were low-pass functions for red-green gratings. For electrophysiology, the highest contrast sensitivity values were found at 0.4 cpd (1.95 ± 0.15). ssVECP CSF was similar to dynamic psychophysical CSF, while static CSF had higher values ranging from 0.4 to 6 cpd (P < 0.05, ANOVA). Blue-yellow chromatic functions showed no specific tuning shape; however, at high spatial frequencies the evoked potentials showed higher contrast sensitivity than the psychophysical methods (P < 0.05, ANOVA). Evoked potentials can be used reliably to evaluate chromatic red-green CSFs in agreement with psychophysical thresholds, mainly if the same temporal properties are applied to the stimulus. For blue-yellow CSF, correlation between electrophysiology and psychophysics was poor at high spatial frequency, possibly due to a greater effect of chromatic aberration on this kind of stimulus.

Chromatic changes to artificial irises produced using different techniques

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Chromatic stability of acrylic resins of artificial eyes submitted to the accelerated aging and polishing

Esthetics and durability of materials used to fabricate artificial eyes has been an important issue since artificial eyes are essential to restore esthetics and function, protect the remaining tissues and help with patients' psychological therapy. However, these materials are submitted to degrading effects of environmental agents on the physical properties of the acrylic resin. OBJECTIVE: This study assessed the color stability of acrylic resins used to fabricate sclera in three basic shades (N1, N2 and N3) when subjected to accelerated aging, mechanical and chemical polishing. MATERIAL AND METHODS: Specimens of each resin were fabricated and submitted to mechanical and chemical polishing. Chromatic analysis was performed before and after accelerated aging through ultraviolet reflection spectrophotometry. RESULTS: All specimens revealed color alteration following polishing and accelerated aging. The resins presented statistically significant chromatic alteration (p<0.01) between the periods of 252 and 1008 h. CONCLUSIONS: Both polishing methods presented no significant difference between the values of color derivatives of resins.

Chromatic discrimination losses in multiple sclerosis patients with and without optic neuritis using the Cambridge Colour Test

We assessed chromatic discrimination in multiple sclerosis (MS) patients both with (ON) and without (no ON) a history of optic neuritis using the Cambridge color test (CCT). Our goal was to determine the magnitude and chromatic axes of any color vision losses in both patient groups, and to evaluate age-related changes in chromatic discrimination in both patient groups compared to normals. Using the CCT, we measured chromatic discrimination along the protan, deutan and tritan axes in 35 patients with MS (17 ON eyes) and 74 age matched controls. Color thresholds for both patient groups were significantly higher than controls` along the protan and tritan axes (P < 0.001). In addition, the ON and no-ON groups differed significantly along all three-color axes (p < 0.001). MS patients presented a progressive color discrimination impairment with age (along the deutan and tritan axes) that was almost two times faster than controls, even in the absence of ON. These findings suggest that demyelinating diseases reduce sensitivity to color vision in both red-green and blue-yellow axes, implying impairment in both parvocellular and koniocellular visual pathways. The CCT is a useful tool to help characterize vision losses in MS and the relationship between these losses and degree of optic nerve involvement.

Assibi A. Amidu 2009. Matrix Nominal Phrases in Kiswahili Bantu. A Study of their Effects on Argument Syntax.

Assibi A. Amidu's contribution is undoubtedly a highly challenging one to the direct study of the Kiswahili Bantu language. Aiming at complementing the existing grammars and monographs of living languages the author intends to illuminate some paradoxes of the Kiswahili syntax and morphology. Having defined this aim he presents a clearly structured monograph to the interested reader, consisting of six chapters, relating to one another.

Extraversion and short-term memory for chromatic stimuli: an event-related potential analysis.

The present study investigated extraversion-related individual differences in visual short-term memory (VSTM) functioning. Event related potentials were recorded from 50 introverts and 50 extraverts while they performed a VSTM task based on a color-change detection paradigm with three different set sizes. Although introverts and extraverts showed almost identical hit rates and reaction times, introverts displayed larger N1 amplitudes than extraverts independent of color change or set size. Extraverts also showed larger P3 amplitudes compared to introverts when there was a color change, whereas no extraversion-related difference in P3 amplitude was found in the no-change condition. Our findings provided the first experimental evidence that introverts' greater reactivity to punctuate physical stimulation, as indicated by larger N1 amplitude, also holds for complex visual stimulus patterns. Furthermore, P3 amplitude in the change condition was larger for extraverts than introverts suggesting higher sensitivity to context change. Finally, there were no extraversion-related differences in P3 amplitude dependent on set size. This latter finding does not support the resource allocation explanation as a source of differences between introverts and extraverts.