Chromatic Detection Research Articles

Multiplexed Nanoscopy via Buffer Exchange.

Understanding cellular functions, particularly in their intricate complexity, can greatly benefit from the spatial mapping of diverse molecules through multitarget single-molecule localization microscopy (SMLM). Existing methodologies, primarily restricting the encoding dimensions to color and lifetime or requiring cyclic staining, often involve broad chromatic detection, specialized optical configurations, or sophisticated labeling techniques. Here, we propose a simple approach called buffer-exchange stochastic optical reconstruction microscopy (beSTORM), which introduces an additional dimension to differentiate between single molecules irrespective of their spectral properties. This method leverages the distinguishable photoblinking responses to distinct buffer conditions, offering a straightforward yet effective means of fluorophore discrimination. Through buffer exchanges, beSTORM achieves multitarget SMLM imaging with minimal crosstalk. Direct integration with expansion microscopy (ExM) demonstrates its capability to resolve up to six proteins at the molecular level within a single emission color without chromatic aberration. Overall, beSTORM presents a highly compatible imaging platform, promising significant advancements in highly multiplexed nanoscopy for exploring multiple targets in biological systems with nanoscale precision.

Ultrasensitive Nanofiber Biosensor: Rapid In Situ Chromatic Detection of Bacteria for Healthcare Innovation.

Rapid detection of bacterial presence in skin wounds is crucial to prevent the transition from acute to chronic wounds and the onset of systemic infections. Current methods for detecting infections, particularly at low concentrations (<1.0 × 105 CFU/cm2), often require complex technologies and direct sampling, which can be invasive and time-consuming. Addressing this gap, we introduce a colorimetric nanofibrous biosensor enabling real-time in situ monitoring of bacterial concentrations in wounds. This biosensor employs a colorimetric hemicyanine dye (HCy) probe, which changes color in response to bacterial lipase, a common secretion in infected wounds. To enhance the biosensor's sensitivity, we incorporated two key materials science strategies: aligning the nanofibers to promote efficient bacterial attachment and localization and integrating Tween 80, a surfactant, within the nanofiber matrix. This combination of physical and chemical cues results in a notable increase in lipase activity. The cross-aligned core-shell nanofibers, embedded with Tween 80 and HCy, demonstrate an immediate and distinct color change when exposed to as low as 3.0 × 104 CFU/cm2 of common pathogens such as Pseudomonas aeruginosa and MRSA. Significantly, the presence of Tween 80 amplifies the colorimetric response, making visual detection more straightforward and four times more pronounced. Our nanobiosensor design facilitates the detection of low-concentration bacterial infections in situ without the need to remove wound dressings. This advancement marks a significant step forward in real-time wound monitoring, offering a practical tool for the early detection of clinical bacterial infections.

Chromatic Aberration Identification of Fair-Faced Concrete Research Based on Multi-Scale Lightweight Structured Data Algorithm

Chromatic aberration is one of the quality defects in the appearance of fair-faced concrete (FFC). The mainly surface chromatic aberration identification (CAI) method being applied is manual observation, which is subjective and time-consuming. A multi-scale lightweight structured data algorithm (MSLSDA) for CAI in FFC is proposed in this manuscript. An unmanned aerial vehicle (UAV) is used for image acquisition. 2368 FFC sample images are collected to build the datasets. The FFC chromatic aberration features are identified by the improved Residual Network Convolutional Neural Network (CNN) framework to achieve chromatic aberration samples quantitative analysis. The method proposed in this manuscript can verify the generalization prediction ability of the MSLSDA for different building samples by generalization prediction set. The results show that the accuracy in CAI samples and chromatic aberration generalization prediction samples can achieve 92.1 and 99.6%, respectively. The FFC chromatic aberration detection platform (FFC-CADP) built by color space conversion, histogram equalization, image color recognition, image noise reduction and image mask algorithm is able to calculate boundary features, geometric parameter features (length and width), chromatic aberration ratio features, total chromatic aberration ratio and number of chromatic aberration.

Edge color difference detection of color image based on artificial intelligence technology

In order to solve the problems of the traditional methods in detecting color image edge chromatic aberration, such as the poor accuracy of detection and the poor detection effect, a color image edge chromatic aberration detection method based on artificial intelligence technology is proposed. The approximate principal component analysis method is used to segment the color image and smooth the image denoising; The linear gray-scale transformation is applied to the color image to enlarge the smaller gray-scale space to the larger gray-scale space according to the linear relationship and obtain the edge information of the color image; The artificial intelligence technology is used to locate the edge sub-pixel of the image to complete the edge color difference detection of the color image. The experimental results show that the detection accuracy of the proposed method is about 98%, and the detection effect is good, which is feasible.

Effect of cone spectral topography on chromatic detection sensitivity.

The spatial and spectral topography of the cone mosaic set the limits for detection and discrimination of chromatic sinewave gratings. Here, we sought to compare the spatial characteristics of mechanisms mediating hue perception against those mediating chromatic detection in individuals with known spectral topography and with optical aberrations removed with adaptive optics. Chromatic detection sensitivity in general exceeded previous measurements and decreased monotonically for increasingly skewed cone spectral compositions. The spatial grain of hue perception was significantly coarser than chromatic detection, consistent with separate neural mechanisms for color vision operating at different spatial scales.

Chromatic detection of Cs ions using polydiacetylene-based vesicles containing crown-ether-like ethylene glycol units

Radioactive 137Cs, which have a half-life of about 30.17 years, are a major source of nuclear pollution and should be detected and removed. For this purpose, a colorimetric, polydiacetylene (PDA) vesicle-based sensor was synthesized to detect Cs ions. The polymer vesicles consisted of commonly used 10,12-pentacosadiynoic acid (PCDA) and its derivatives. One of the derivatives that contained tetraethylene glycol (TEG) units at the end of the PCDA side chain, and thus it acted as a chelating agent that surrounded the Cs ion like a crown ether. As a result, the main chain of the PDA was distorted by the chelation of TEG and Cs ions, resulting in a blue-red color change. To provide selectivity to the PDA vesicles, another derivative was incorporated to the PDA vesicles with controlled amount, which was not responsive to alkali metal ions. The changes in the colorimetric response of the vesicles were not observed in the presence of other alkali metal ions such as Na, K, and Rb ions, indicating that the TEG units fitted well in size with the ionic radius of the Cs ion, resulting in high selectivity. Solid-state PDA film was also fabricated to provide selective detection of Cs ions.

Spatio-chromatic sensitivity explained by post-receptoral contrast.

We measured and modeled visibility thresholds of spatial chromatic sine-wave gratings at isoluminance. In two experiments we manipulated the base color, direction of chromatic modulation, spatial frequency, the number of cycles in the grating, and grating orientation. In Experiment 1 (18 participants) we studied four chromatic modulation directions around three base colors, for spatial frequencies 0.15-5 cycles/deg. Results show that the location, size and orientation of fitted ellipses through the observer-averaged thresholds varied with spatial frequency and base color. As expected, visibility threshold decreased with decreasing spatial frequency, except for the lowest spatial frequency, for which the number of cycles was only three. In Experiment 2 (27 participants) we investigated the effect of the number of cycles at spatial frequencies down to 0.025 cycles/deg. This showed that the threshold elevation at 0.15 cycles/deg in Experiment 1 was at least partly explained by the small number of cycles. We developed two types of chromatic detection models and fitted these to the threshold data. Both models incorporate probability summation across spatially weighted chromatic contrast signals, but differ in the stage at which the contrast signal is calculated. In one, chromatic contrast is determined at the cone receptor level, the dominant procedure in literature. In the other model, it is determined at a postreceptoral level, that is, after cone signals have been transformed into chromatic-opponent channels. We applied Akaike's Information Criterion to compare the performance of the models and calculated their relative probabilities and evidence ratios. We found evidence in favor of the second model and conclude that postreceptoral contrast is the most accurate determinant for chromatic contrast sensitivity.

Chromatic detection of glucose using polymerization of diacetylene vesicle

ABSTRACTA polydiacetylene vesicle was used to fabricate glucose sensor, allowing feasible colorimetric detection. The vesicle was formed by sonication of 10,12‐pentacosadiynoic acid (PCDA). H2O2 formed by the reaction between glucose and glucose oxidase functioned as the initiator for the polymerization of PCDA in the presence of horseradish peroxidase. The solution turned blue after the polymerization of PCDA vesicle. Thus, the glucose concentration could be detected to the concentration level that turns the solution to blue. The ultraviolet absorbance of glucose solution was proportional to glucose concentration. The results of this study indicate that glucose concentration upto 1 mM can be detected by change in blue color by eyes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46394.

Determinants of Colour Constancy and the Blue Bias.

We investigated several sensory and cognitive determinants of colour constancy across 40 illumination hues. In the first experiment, we measured colour naming for the illumination and for the colour induced by the illumination on the colorimetric grey. Results confirmed that the induced colours are approximately complementary to the colour of the illumination. In the second experiment, we measured colour constancy using achromatic adjustments. Average colour constancy was perfect under the blue daylight illumination and decreased in colour directions away from the blue daylight illumination due to undershooting and a strong blue bias. Apart from this blue bias, colour constancy was not related to illumination discrimination and to chromatic detection measured previously with the same setup and stimuli. We also observed a strong negative relationship between the degree of colour constancy and the consensus of naming the illumination colour. Constancy coincided with a low naming consensus, in particular because bluish illumination colours were sometimes seen as achromatic. Blue bias and category consensus alone explained >68%, and all determinants together explained >94% of the variance of achromatic adjustments. These findings suggest that colour constancy is optimised for blue daylight.

Labeling the lines: A test of a six-mechanism model of chromatic detection.

Six linear chromatic mechanisms are sufficient to account for the pattern of threshold elevations produced by chromatic noise masking in the (L,M) plane of cone space (Shepard, Swanson, McCarthy, & Eskew, 2016). Here, we report results of asymmetric color matching of the threshold-level tests from that detection study and use those matches to test the detection model. We assume the mechanisms are univariant labeled lines (Rushton, 1972; Watson & Robson, 1981), implying that the chromaticities of physically different stimuli that are detected by a single mechanism should all be the same-they are postreceptoral metamers-but the chromaticities of two stimuli detected by different mechanisms should be different. The results show that color matches fall into six clusters in CIE (u',v') space (across all the noise conditions) and that these clusters correspond closely to the six mechanisms in the model. Most importantly, where the detection model determines that a given test angle is detected by different mechanisms under different noise conditions, the hue of that test angle changes in a consistent way. These color matches allow us to apply a color label to each of the mechanisms, confirm the six-mechanism model, and quantify the hue signaled by each mechanism.

LとM錐体ノイズマスキングによる色検出閾値とL/M錐体比との関係性(視聴覚の基礎と応用,マルチモーダル,感性情報処理,一般)

LとM錐体ノイズマスキングによる色検出閾値とL/M錐体比との関係性(視聴覚の基礎と応用,マルチモーダル,感性情報処理,一般)

The Study on the Application of Antioxidant in Radiation Synthetic Preservation Techniques of Fresh or Chilled Chicken

In view of the preservation of fresh chicken focusing on broiler, with the lack of material on san-huang chicken. used the 84 disinfectant whose concentration was 1:86 wash the killed san-huang chicken for 1 min, dropped the core temperature to 4°C in 30 min and did acid treatment for 24h, then immersed in the concentration of 0.3g/L tea polyphenols+0.2g/L D-sodium erythroblast composite solution for 5 min, drained and vacuum packed, treated with the radiation source of 60Co as a 4kGy dose, and preserved in 4°C.The result showed, at the end of preservation CFU increased from 3.8×103 to 8.7×105CFU/g, epiphytic bacteria were Pseudomonas and Enterobacteriaceae, TVB-N increased from 8.24mg/100g to 14.8mg/100g, POV increased from 3.6meq/kg to 7.8meq/kg; texture profile analysis resulted that with no change of adhesion, cohesion, the hardness, elasticity and chewiness of Chicken decline, chromatic detection resulted that L value and a value increase but b value decline, the quality of fresh chicken met the national food safety standards. As a result, after comprehensive radiation treatment, the shelf life of fresh chicken was 28d.

Labeling the Lines: Asymmetric Color Matches Compared to a Six Mechanism Chromatic Detection Model

Labeling the Lines: Asymmetric Color Matches Compared to a Six Mechanism Chromatic Detection Model

A model of selective masking in chromatic detection.

Narrowly tuned, selective noise masking of chromatic detection has been taken as evidence for the existence of a large number of color mechanisms (i.e., higher order color mechanisms). Here we replicate earlier observations of selective masking of tests in the (L,M) plane of cone space when the noise is placed near the corners of the detection contour. We used unipolar Gaussian blob tests with three different noise color directions, and we show that there are substantial asymmetries in the detection contours-asymmetries that would have been missed with bipolar tests such as Gabor patches. We develop a new chromatic detection model, which is based on probability summation of linear cone combinations, and incorporates a linear contrast energy versus noise power relationship that predicts how the sensitivity of these mechanisms changes with noise contrast and chromaticity. With only six unipolar color mechanisms (the same number as the cardinal model), the new model accounts for the threshold contours across the different noise conditions, including the asymmetries and the selective effects of the noises. The key for producing selective noise masking in the (L,M) plane is having more than two mechanisms with opposed L- and M-cone inputs, in which case selective masking can be produced without large numbers of color mechanisms.

The Verriest Lecture: Short-wave-sensitive cone pathways across the life span.

Structurally and functionally, the short-wave-sensitive (S) cone pathways are thought to decline more rapidly with normal aging than the middle- and long-wave-sensitive cone pathways. This would explain the celebrated results by Verriest and others demonstrating that the largest age-related color discrimination losses occur for stimuli on a tritan axis. Here, we challenge convention, arguing from psychophysical data that selective S-cone pathway losses do not cause declines in color discrimination. We show substantial declines in chromatic detection and discrimination, as well as in temporal and spatial vision tasks, that are mediated by S-cone pathways. These functional losses are not, however, unique to S-cone pathways. Finally, despite reduced photon capture by S cones, their postreceptoral pathways provide robust signals for the visual system to renormalize itself to maintain nearly stable color perception across the life span.

A Readable Chromatic Biosensor with a Tunable Detection Threshold

Rapid and readable chromatic detection of antigen is essential for medical and clinical applications as they are inexpensive, portable and simple in operating process. In addition, results from chromatic biosensors can be easily readout without any equipment or instrument collocation. However, only a few studies accomplished the goal by detecting the antigen via this strategy; even though, the detection range is still narrow and only could be applicate on some specific disease identification. Still, most of the chromatic biosensors are continuing color transition and hard to identify the disease at critical point. Therefore, it is essential to develop a wide-detecting ranged or detecting range tunable chromatic biosensor revealing considerably color-change for numerous diseases recognition. This article presents a detection range tunable readable chromatic biosensor for antigen detection, demonstrated by the detection of human serum albumin (HSA). First, the HSA sample was pre-conjugated to chitosan to form HSAchitosan complex, then, the HSA-chitosan complex was utilized to synthesize Ag NPs. According to the color shown by the synthesized Ag NPs, 0.01-0.3 mg/ml HSA sample could be determined. Furthermore, the detection range could be adjusted to 0.001-0.1 or 0.1-1 through decreasing or raising the chitosan-conjugating concentration, showing the potential for more disease identification application.

Chromatic detection from cone photoreceptors to V1 neurons to behavior in rhesus monkeys.

Chromatic sensitivity cannot exceed limits set by noise in the cone photoreceptors. To determine how close neurophysiological and psychophysical chromatic sensitivity come to these limits, we developed a parameter-free model of stimulus encoding in the cone outer segments, and we compared the sensitivity of the model to the psychophysical sensitivity of monkeys performing a detection task and to the sensitivity of individual V1 neurons. Modeled cones had a temporal impulse response and a noise power spectrum that were derived from in vitro recordings of macaque cones, and V1 recordings were made during performance of the detection task. The sensitivity of the simulated cone mosaic, the V1 neurons, and the monkeys were tightly yoked for low-spatiotemporal-frequency isoluminant modulations, indicating high-fidelity signal transmission for this class of stimuli. Under the conditions of our experiments and the assumptions for our model, the signal-to-noise ratio for these stimuli dropped by a factor of ∼3 between the cones and perception. Populations of weakly correlated V1 neurons narrowly exceeded the monkeys' chromatic sensitivity but fell well short of the cones' chromatic sensitivity, suggesting that most of the behavior-limiting noise lies between the cone outer segments and the output of V1. The sensitivity gap between the cones and behavior for achromatic stimuli was larger than for chromatic stimuli, indicating greater postreceptoral noise. The cone mosaic model provides a means to compare visual sensitivity across disparate stimuli and to identify sources of noise that limit visual sensitivity.

Chromatic response of polydiacetylene vesicle induced by the permeation of methotrexate.

The noble vesicular system of polydiacetylene showed a red shift using two types of detecting systems. One of the systems involves the absorption of target materials from the outer side of the vesicle, and the other system involves the permeation through the vesicular layers from within the vesicle. The chromatic mixed vesicles of N-(2-aminoethyl)pentacosa-10,12-diynamide (AEPCDA) and dimethyldioctadecylammonium chloride (DODAC) were fabricated by sonication, followed by polymerization by UV irradiation. The stability of monomeric vesicles was observed to increase with the polymerization of the vesicles. Methotrexate was used as a target material. The polymerized mixed vesicles having a blue color were exposed to a concentration gradient of methotrexate, and a red shift was observed indicating the adsorption of methotrexate on the polydiacetylene bilayer. In order to check the chromatic change by the permeation of methotrexate, we separated the vesicle portion, which contained methotrexate inside the vesicle, and checked chromatic change during the permeation of methotrexate through the vesicle. The red shift apparently indicates the disturbance in the bilayer induced by the permeation of methotrexate. The maximum contrast of color appeared at the equal molar ratio of AEPCDA and DODAC, indicating that the formation of flexible and deformable vesicular layers is important for red shift. Therefore, it is hypothesized that the system can be applicable for the chromatic detection of the permeation of methotrexate through the polydiacetylene layer.

Improved SC-FDE With Noise Filtering for Directly Detected WDM-PON

We propose a modified single-carrier frequency domain equalization (SC-FDE) scheme implemented in directly detected wavelength-division-multiplexed passive optical networks (WDM-PONs). A time-clipping technique is used in FDE to perform noise filtering. In the simulation, where the channel is modeled with chromatic dispersion and direct detection, performance improvement is achieved by exploring the clipping position and retained gradient vector length. In the experiment, we investigate the time-clipping SC-FDE implemented in 10-Gb/s direct-detected WDM-PON using an uncooled free-running 1550-nm vertical cavity surface emitting laser. After 30-km transmission, it is observed that the time-clipping scheme can bring roughly 1-dB power penalty improvement over conventional equalization schemes.

V1 mechanisms underlying chromatic contrast detection

To elucidate the cortical mechanisms of color vision, we recorded from individual primary visual cortex (V1) neurons in macaque monkeys performing a chromatic detection task. Roughly 30% of the neurons that we encountered were unresponsive at the monkeys' psychophysical detection threshold (PT). The other 70% were responsive at threshold but on average, were slightly less sensitive than the monkey. For these neurons, the relationship between neurometric threshold (NT) and PT was consistent across the four isoluminant color directions tested. A corollary of this result is that NTs were roughly four times lower for stimuli that modulated the long- and middle-wavelength sensitive cones out of phase. Nearly one-half of the neurons that responded to chromatic stimuli at the monkeys' detection threshold also responded to high-contrast luminance modulations, suggesting a role for neurons that are jointly tuned to color and luminance in chromatic detection. Analysis of neuronal contrast-response functions and signal-to-noise ratios yielded no evidence for a special set of "cardinal color directions," for which V1 neurons are particularly sensitive. We conclude that at detection threshold--as shown previously with high-contrast stimuli-V1 neurons are tuned for a diverse set of color directions and do not segregate naturally into red-green and blue-yellow categories.