Search

In this paper, we introduce Pixelator v2, a novel perceptual image comparison method designed to enhance security and analysis through improved image difference detection. Unlike traditional metrics such as MSE, Q, and SSIM, which often fail to capture subtle but critical changes in images, Pixelator v2 integrates the LAB (CIE-LAB) colour space for perceptual relevance and Sobel edge detection for structural integrity. By combining these techniques, Pixelator v2 offers a more robust and nuanced approach to identifying variations in images, even in cases of minor modifications. The LAB colour space ensures that the method aligns with human visual perception, making it particularly effective at detecting differences that are less visible in RGB space. Sobel edge detection, on the other hand, emphasises structural changes, allowing Pixelator v2 to focus on the most significant areas of an image. This combination makes Pixelator v2 ideal for applications in security, where image comparison plays a vital role in tasks like tamper detection, authentication, and analysis. We evaluate Pixelator v2 against other popular methods, demonstrating its superior performance in detecting both perceptual and structural differences. Our results indicate that Pixelator v2 not only provides more accurate image comparisons but also enhances security by making it more difficult for subtle alterations to go unnoticed. This paper contributes to the growing field of image-based security systems by offering a perceptually-driven, computationally efficient method for image comparison that can be readily applied in information system security. [ABSTRACT FROM AUTHOR]

Hydrothermal treatment of wood, particularly steaming with saturated water steam, is often used to achieve a more intensive and homogenous wood color or to vary its hue. However, information on pear wood (Pyrus communis L.) steaming is limited in the available literature. This paper investigates the influence of steaming on the color of pear wood. Green, water-saturated samples of pear wood heartwood and sapwood were steamed with saturated water steam for 24 h at 98 °C. The color of the heartwood and sapwood was assessed both visually and with a standard three-stimulus colorimeter using the CIEL*a*b* system, and compared to the natural color of pear-wood. Additionally, FT-IR spectrometry was employed to analyze chemical changes in the wood samples. The results showed that both heartwood and sapwood experienced a decrease in lightening (L*), an increase in redness (a*), and a decrease in yellowness (b*) during steaming. Furthermore, a trend toward the equalization of L*, a*, and b* parameters between heartwood and sapwood over time was observed. FT-IR spectroscopy revealed that the chemical changes during steaming were primarily related to extractives and hemicelluloses, with no significant changes in cellulose and lignin. The obtained results suggest that pear wood color can be equalized to some extent by steaming and that the extent of the color change to darker tones is dependent on steaming time. [ABSTRACT FROM AUTHOR]

Color vision deficiency (CVD) is an eye disease caused by genetics that reduces the ability to distinguish colors, affecting approximately 200 million people worldwide. In response, image recoloring approaches have been proposed in existing studies for CVD compensation, and a state-of-the-art recoloring algorithm has even been adapted to offer personalized CVD compensation; however, it is built on a color space that is lacking perceptual uniformity, and its low computation efficiency hinders its usage in daily life by individuals with CVD. In this paper, we propose a fast and personalized degree-adaptive image-recoloring algorithm for CVD compensation that considers naturalness preservation and contrast enhancement. Moreover, we transferred the simulated color gamut of the varying degrees of CVD in RGB color space to CIE L*a*b* color space, which offers perceptual uniformity. To verify the effectiveness of our method, we conducted quantitative and subject evaluation experiments, demonstrating that our method achieved the best scores for contrast enhancement and naturalness preservation. [ABSTRACT FROM AUTHOR]

Canopy coverage-based crop growth monitoring is highly dependent on the performance of crop segmentation algorithms. Under field conditions, crop segmentation for unmanned aerial vehicle (UAV) imagery should be sophisticated considering geometric distortion of images by wind and illumination variations. Under Korean cultivation conditions, a plastic mulch used to restrict weeds and prevent cold weather damage increases the complexity of the image background. In particular, on-site monitoring of onion and garlic growth has been limited by their morphology because they have long narrow leaves. The ultimate goal of this study was to quantify the growth parameters of onion and garlic at multiple growth stages using red, green, and blue (RGB) imagery obtained with UAVs. Canopy coverage and plant height were used as predictor variables to develop mathematical models to estimate the fresh weights of onion and garlic. The use of a CIE L*a*b* color space and mean shift (MS) algorithm enhanced the extraction of the canopy coverage of onion and garlic from complex backgrounds, including plastic mulch, soil, and shadows under varying illumination conditions. Multiple linear regression models consisting of the a* band-based vegetation fraction (VF) and structure from motion (SfM)-based plant height (PH) fitted the fresh weight data of onion and garlic well with high coefficients of determination (R2) ranging from 0.82 to 0.92. The validation results showed an almost 1:1 slope with highly linear relationships (R2 > 0.82) between the onion and garlic fresh weights obtained with the UAV RGB imagery and actual fresh weights, confirming that the UAV-RGB imagery based on the use of the a*band and PH can be used to quantify the spatial and temporal variability of onion and garlic growth parameters during the growing season.

In the present experiment, a study was conducted to investigate the effect of conservation treatment of an Arabic manuscript on its chromatic characteristics. For this purpose, extremely valuable, unrestored manuscripts (18 - 19th century) were selected from the archives of the National Library "St. St. Cyril and Methodius", on which spectrophotometric chromatic characteristics were measured. The research was conducted at the restoration center of the National Library. The following processes were applied to the manuscript: mechanical cleaning and deacidification. Measurements of color characteristics were taken indifferent parts of the manuscript after each stage of the treatment: before treatment, after mechanical cleaning, after deacidification. The following parameters - CIE Lab, CIE Lch, ΔEab, ΔE2000, ΔL, Δc, Δh was calculated. Based on the results obtained, the changes and effects of each of the chromatic parameters were determined. [ABSTRACT FROM AUTHOR]

Accurate classification of malignant and benign skin lesions is crucial in dermatology. In this novel research, we propose robust image analysis methodology for skin lesion classification that integrates color-based segmentation with luminosity analysis. Our approach is evaluated on a dataset of 400 skin images, with equal representation of malignant and benign samples. By computing mean color values for the Red Channel Color (RCC), Green Channel Color (GCC), and Blue Channel Color (BCC) in groups of 10 samples, we establish a classification range for precise diagnosis, this research introduces a novel dimension by harnessing the potential of the CIE Lab Color characteristics for skin lesion detection as the most reliable scale for distinguishing between benign and malignant samples. The smaller and more thought variety ranges saw in the glow examination improve difference and perceivability, consequently working with prevalent sore separation. By featuring the meaning of mean histograms for each variety channel, this complete exploration adds to propelling the area of dermatology and presents an imaginative methodology that holds guarantee for PC helped conclusion frameworks in skin malignant growth discovery. [ABSTRACT FROM AUTHOR]

Quantification of beer color of craft unfiltered, hazy, seltzer, and fruited beer styles can be problematic due to turbidity and unconventional ingredients. A novel integrating cavity spectrometer (ICS), designed to eliminate the effect of light scatter by the sample was employed to determine if it was able to more accurately quantify beer color compared to a conventional scanning spectrophotometer (CSS). A CSS was employed to measure the absorbance and transmission of 15 filtered and unfiltered craft brewery beer samples to determine the SRM color value and tristimulus color values. The ICS measures absorbance with a 430 nm LED to determine the single-point SRM value for each beer. The SRM values of unfiltered or 0.2 µm filtered beer samples were compared using Bland-Altman analysis and regression fits. Filtered and very clear beers showed strong agreement between the methods and Bland-Altman analysis confirmed their equivalence, particularly for SRM <25. Using the ICS alone, filtered beer versus unfiltered beer showed highly correlated values and narrow limits of agreement, successfully negating the effects of turbidity. In conclusion, SRM determination by ICS is equivalent to standard spectrophotometer single-point methods and superior in accurately determining the SRM color of hazy beers without filtration or centrifugation. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of spraying plants with 0.03% salicylic acid (SA), 0.7% calcium nitrate (Ca), and 0.03% salicylic acid together with 0.7% calcium nitrate (SA + Ca) on plant growth, yield, and fruit quality of peppers grown in a mineral wool substrate. The control plants were sprayed with water (C). Two red-fruited sweet pepper cultivars were used in the study: 'Aifos', and 'Palermo', which produce fruits characterized by different shapes. Biometric measurements of the plants showed a higher growth rate of pepper plants when SA and Ca were applied foliarly compared to the control. Plants treated simultaneously with SA and Ca were characterized by the highest steady-state fluorescence yield [Fs]. The relative chlorophyll content of pepper leaves was also higher in plants sprayed with SA, Ca, and SA + Ca than in plants in the control. The analysis of pepper yield showed in both cultivars the effect of foliar treatment of plants with SA and Ca and SA + Ca on increasing pepper resistance to the occurrence of Ca deficiency on pepper fruit (Blossom end rot). Pepper fruits harvested from plants treated with SA, Ca, and SA + Ca had more juicy flesh. [ABSTRACT FROM AUTHOR]

In our daysdental bleaching is required in dental practices but it has to be proceeded by a professional dental cleaning. A successful procedure can be made using Prophy-pearls granulesthat are particularly gentle on the teeth and provide optimum cleaning due to their round surfaces. The aim of this paper is to study the influence of Prophy-pearls granules on dental enamel, composite veneers and acrylic teeth after therapeutic administration of propolisethanolic extract. The study focuses on the aesthetic parameters such as colour, brightness, translucence. All thesamples were immerged in propolis extract for 5 days after a professional cleaning. Every day image captures were made to all the existing samples. The CIE L*a*b* colour space was used to chromatically characterize the samples. In order to compare the samples, direct chromatic comparison was done by colour difference calculation (ΔE). The initial samples and professional cleaned samples has no significant chromatic differences, but they differ significantly more than four times than between them. The experiments made during the study were used in orderto discriminate between the time stamps teeth staining status and the sandblasting treatment. The method used was the digital image capturing and colour image analysis (CIA). The results of the study revealed that the colour image analysis can discriminate between the propolisethanolic extract stained and non-stained veneers and natural teeth. Furthermore, the professional cleaning process was successful from the chromatic point of view.

Drip irrigation is a water-saving and fertilizer-saving application technology used in recent years, with which the frequency of drip irrigation nitrogen application has not yet been determined. In order to investigate the effects of different drip irrigation nitrogen application frequencies on the processing quality of medium-gluten wheat (Jimai22) and strong-gluten wheat (Jimai20 and Shiluan02-1), a two-year field experiment was carried out. Two frequencies of water and N application were set under the same conditions of total N application (210 kg·ha−1) and total irrigation (120 mm): DIF4, consisting of four equal applications of water and N (each of 30 kg·ha−1 of N application and 30 mm of irrigation) and DIF2, consisting of two equal applications of water and N (each of 60 kg·ha−1 of N application and 60 mm of irrigation). The results showed that IF4 significantly increased protein content by 2–8.6%, wet gluten content by 4.5–22.1%, and hardness value (p > 0.05), and PC2 was considered as a protein factor; the sedimentation value was highly significantly correlated with most of the parameters of the flour stretch (p < 0.01). DIF4 improved the stretching quality, and the flour quality of Jima22 was decreased, the flour quality of strong-gluten wheats Jimai20 and Shiluan02-1 was improved, and PC1 was considered to be the dough factor. In conclusion, although the frequency of nitrogen application by drip irrigation increased the protein factor and improved the tensile quality, the flour quality was not necessarily enhanced. [ABSTRACT FROM AUTHOR]

• Use of Ag-functionalized nanocrystalline cellulose on two paper types is studied. • Spectral reflectance is measured and CIE L*a*b* coordinates under D65 are obtained. • The treatment induces a pinkish coloration mainly evident in the inoculation region. • Reactions to the treatments of the two types of paper are different. • The proposed method can be applied to analyze effects of any type of treatment. Artifacts made of paper (books, manuscripts, and other documents) represent a valuable part of cultural heritage. They are particularly fragile compared to other objects due to the multiple physical, chemical, and biological factors able to degrade the paper basic constituents, i.e., cellulose, hemicellulose, and lignin. Moreover, hemicellulose and lignin represent an ideal growth substrate for proliferation of microorganisms and fungi. Regarding this latter aspect, researchers have experimented several methods to prevent and control fungal development on paper documents, but, sometimes, these treatments present themselves collateral effects, being responsible for the variation of paper chromatic appearance. Recently, a suspension made of crystalline nanocellulose with the adding of silver nanoparticles was tested as antifungal method. Actually, the crystalline nanocellulose has been already experimented as starting material for preservation and consolidation treatments on paper, but the adding of silver nanoparticles also provided the suspension with a broad-spectrum antimicrobial action. The aim of the research is to investigate the potential effects of the so-prepared suspension in modifying the optical characteristics of the treated paper. To do that, two different types of paper were analyzed: Whatman and Amalfi. Squared paper samples (3 cm side) were prepared, subjected to artificial ageing, and then inoculated with nanocrystalline cellulose (CNC) and with Ag-functionalized nanocrystalline cellulose (CNC/Ag). Spectral reflectance measurements were performed on the samples, and the CIE L*a*b* chromatic coordinates under D65 were obtained. Comparing the measurements referred to samples treated with CNC and those treated with CNC/Ag, it has been possible to describe the effects due to the presence of silver in the suspension. Obtained results demonstrate that the chromatic variations of the samples treated with CNC/Ag are higher than those referred to the samples treated with CNC. Specifically, the chromatic variations ΔE* D65 range from 0.2 to 10.5 for the Whatman paper and from 0.3 to 5.1 for the Amalfi one. Moreover, it has been shown that the two types of paper react in a different way to the treatments and that the alterations are not homogenous on the entire paper sample, but more evident in the inoculation region in which pinkish spots arise. Finally, it has been proved that the alterations are not stable over time, but, especially for Whatman paper, they become more evident after one month and half from the preparation of the samples. [ABSTRACT FROM AUTHOR]

ABSTRACT: The effect of sous-vide (SV), microwave (M) cooking, and stewing (S) on selected functional properties of goose meat were investigated in this study. It was measured cooking loss (CL), texture and color parameters, and sensory evaluation was carried out. The material were 96 breast muscles (BM, n = 48 with skin and subcutaneous fat and n = 48 without skin) from 17-wk-old “Polish oat geese.” The kind of heat treatment and the type of goose meat and interaction the type of meat × heat treatment affected the amount of CL. The lowest value of CL was stated for SV samples. The meat with skin was characterized by a lower shear force value (SF), hardness, gumminess, and chewiness than samples without skin for all cooking methods. There were no differences in SF value for M and S samples with skin. The S samples characterized by the highest value of SF, hardness and the SV meat by the lowest for both kind of meat. The M samples characterized by the higher value of cohesiveness, gumminess and chewiness compare to SV and S meat. All instrumental color parameters were significantly affected by cooking technology (P = 0.001). There were differences in color lightness (L*) of investigated cooked samples. The SV meat had the highest value of L* parameter and was characterized by a lighter color among others. The highest decrease in a* value was stated for S and lowest for SV meat. The SV showed more intense red color than remaining samples. The a* value decreased and b* parameter increases with an increase the heat treatment temperature. The value of b* was higher in S (about 100°C) samples than in raw meat and processed by SV (70°C). From consumer point of view the best color had goose breast muscles subjected to SV process. Considering all tested sensory features, the overall palatability of SV goose samples was rated as excellent, S as very good and M as good.

ABSTRACT: The objective of this study was to investigate the changes in the functional properties (pH, water holding capacity [WHC], water binding capacity [WBC], cooking losses [CL], defrosting losses [DL]), color parameters (L*, a*, b*, C, h°, ΔE), and sensory evaluation of breast (BM) and leg (LM) muscles from 17-wk-old female White Kołuda geese packaged in a vacuum and stored in frozen conditions at −20°C. During 17 wk, the geese were fed ad libitum on the same complete feed. The samples (18 BM and 18 LM) from the right part of the carcasses were stored for 30, 90, 80, 270, and 365 d. The changes in functional properties were established using a standard method used in the meat industry, according to Wierbicki et al. (1962), Grau and Hamm (1953), and CIE, (1986). Sensory evaluation was established according to defined parameters in PN-ISO 8586-2:2008. The time of frozen storage affected the decrease in WHC and WBC of BM and LM. Moreover, the LM can be characterized by a higher WHC and WBC compared to the values in the BM. It was established that CL and DL, which are the critical quality indicators, negatively increased in BM and LM during frozen storage. Considering the sensory evaluation and L*, a*, b*, C, it was established that changes in BM and LM during frozen storage were unfavorable. The scores given for smell, taste, consistency, and general appearance, as also L*, a*, and b* parameters decreased significantly during frozen storage. In addition, BM received lower scores for general appearance (at 180th and 270th day), and L* (in all frozen storage), than LM. BM and LM characterized the parameter ΔE in the range of 0.44 to 1.45, which allowed us to conclude that slight color differences were visible in these muscles (

The main modifications of thermal and colorimetric parameters after thermal aging of DGEBA/TETA system (plain epoxy) and fique-fiber woven fabric-reinforced epoxy composites are described. As a preliminary study, thermal analysis was carried out on epoxy matrix composites reinforced with 15, 30, 40 and 50% fique-fiber woven fabric. After this previous analysis, the 40% composite was chosen to be thermally aged, at 170 °C. Three exposure times were considered, namely, 0, 72, 120 and 240 h. Samples were studied by thermogravimetric analysis (TGA), differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and colorimetry analysis. Significant color changes were observed after thermal aging combined with oxidation. It was also found that the thermal behavior of the plain epoxy showed greater resistance after thermal exposure. By contrast, the composites were more sensitive to temperature variations as a result of thermal stresses induced between fique fibers and the epoxy matrix. [ABSTRACT FROM AUTHOR]

As an environmentally friendly physical modification of wood, wood heat treatment technology can effectively improve wood color, dimensional stability and biological durability of wood, so it is widely used in the functional improvement of wood. In this study, Castanopsis hystrix wood was used as the research object, water vapor was used as the heating medium and the wood was heat treated for 1. 5-4. 5 h under the temperature of 150-210 ℃ . The color changes of Castanopsis hystrix wood under different hear treatment conditions were studied, and the correlation between color and dimensional stability, mechanical properties and biological durability was also discussed. The results showed that the lightness index L ∗ decreased, the red green index a ∗ and the yellow blue index b ∗ increased slowly, and the lightness difference ΔL ∗ and the total color difference ΔE ∗ increased gradually, indicating that the color of heat treated Castanopsis hystrix wood gradually changed from primary color to dark color. The maximum reduction of dry shrinkage rate and wet expansion rate was 55. 7% and 69. 7%, respectively, indicating the dimensional stability was obviously improved. The flexural strength and elastic modulus were decreased by 3. 1%-30. 2% and 3. 7%-20. 7%, respectively. The termite resistance and rot resistance grade were not improved. In the temperature and time range involved in this experiment, there was a second-order parabolic relationship between the color change of heat-treated wood and the weight loss rate of termite-eaten wood, the survival rate of termite, and the weight loss rate of brown rot wood and white rot wood. However, the correlation between the color change of heat-treated Castanopsis hystrix wood and dimensional stability and bending resistance was unclear. Therefore, it is feasible to predict and evaluate the anti -biological durability of heat treated Castanopsis hystrix wood by color change. [ABSTRACT FROM AUTHOR]

An image edge detection algorithm using multi-directional and multi-scale Gabor filters is proposed in this paper. The main merit of this method is that high edge detection accuracy can be obtained while maintaining noise robustness. The approach proposed in this paper consists of three procedures: firstly, the transformation to the CIE L*a*b* color space, which has a wide shading area and uniform distribution; secondly, under different scales, the edge feature information of the image is extracted from several different directions by Gabor filters, and a new edge strength map is obtained by feature fusion; thirdly, the new fused edge strength map is enhanced with local features, and a noise-resistant image edge detector is obtained under a novel hysteresis threshold calculation. The experiments illustrate that, compared to the methods involved, the designed edge detector outperforms by about 2% to 4%, and also shows competitive performance regarding the ability to handle noise. [ABSTRACT FROM AUTHOR]

Processed cheeses (PC) are products resulting from the mixing and melting of rennet cheese, emulsifying salts, water, and possibly various additional ingredients. They are considered good vehicles for new ingredients, including plant-based ones. In addition to the health-promoting effects of plant-based ingredients, some of them can also affect positively the quality characteristics of PC (e.g., texture, taste, and consistency) and their addition may reduce the amount of emulsifying salts used. The aim of the study was to determine the possibility of the addition of 0.5, 1.0, 2.0, and 3.0% white mulberry (M), chia (Ch), green barley (GB), or spirulina (S) to PC and the effects on selected characteristics of these products (chemical composition, pH, water activity, color parameters, texture, and sensory properties). In all PC variants, a significance decrease in the dry matter content was observed with an increase in the additive level. The use of plant-based additives allowed us to reduce the addition of emulsifying salts by 50% compared to their typical amounts and the share of rennet cheese in the PC recipe by approximately 18%, which had a beneficial effect on the nutritional value of these products. The use of 3% GB, Ch, or M as additives to PC enabled a reduction in its sodium content by 27, 27, and 42%, respectively, compared to the control cheese. Among the tested additives, GB caused the greatest increase in the hardness of PC (even at the amount of 0.5%), indicating that is beneficial and can be used in the production of sliced PC. All the additives either significantly reduced the adhesiveness of PC or had no effect on this parameter. In terms of sensory characteristics, the highest acceptable addition of GB was 0.5%, and that for S and Ch was 1%, while the addition of M, even at 3%, was assessed very positively. The results of this research may be helpful in the development of new recipes for processed cheeses obtained in industrial conditions. [ABSTRACT FROM AUTHOR]

The fall coloration of temperate tree leaves is a phenomenon of nature that ranges in color from pale yellows, oranges, and purples to dark reds. Although some evolutionary forces and weathered mechanisms (e.g., light and frost protection) cause variations in leaf color within and among species, no full explanation is found regarding fall coloration. This study phonologically monitored Torminalis glaberrima leaves from May until at the end of November in terms of fall coloration and senescence properties. The study presents the average color coordinate values of Torminalis glaberrima leaves, starting from May and continuing through November. Torminalis glaberrima leaves show an intense green color from May to June. We have used CIE L*a*b (1976) color space to determine discoloration intensity. As the seasons change, however, the leaves become darker into November (L = 25.67), with leaf discolorations becoming clearly distinguishable. We selected color values of leaves of Torminalis glaberrima at May as control, and as vegetation continues, compared to color changes throughout study (end of November). Accordingly, we measured total color differences (ΔE). The highest change in coloration was found in November (ΔE = 56.86) followed by October (ΔE = 44.71), September (ΔE = 42.32), August (ΔE = 15.37), July (ΔE = 5.86), and June (ΔE = 2.14). Notably, the highest color difference ΔE = 44.56 was found from August to September, and the lowest from May to June (ΔE = 2.14). Except for the leaves’ GE brightness values, which show very low correlations over time, all other color coordinate values for CIE L*a*b* and hue values show some color level correlations over time. [ABSTRACT FROM AUTHOR]

[Objectives]This paper aimed to analyze the color changes after long-term use of the Royal Horticultural Society Color Chart(RHSCC), a commonly used tool for flower color testing, and the influence of color change on flower color determination and variety grouping. [Methods]The color determination of the new(unused)and old(used for 10 years)RHSCC was carried out by using chromaticity meter, and color determination and color grouping of 150 varieties of Kalanchoe blossfeldiana were carried out by using chromaticity meter and the new and the old RHSCC respectively, and the advantages and disadvantages of the three color grouping results were analyzed. [Results]There was a significant statistical difference between the old and the new RHSCC at the statistical level(P<0.001), and the difference was positively correlated with the frequency of color block use and the distance of binding holes. The color difference between two sets of RHSCC was less than 1.5 CIE LAB units detectable by human eye except for one of 884 color blocks. Two sets of RHSCC were 100% consistent in the determination of flower color. On the other hand, RHSCC and visual variety grouping had some problems, such as unclear boundary, too large, too small or overlapping. Based on CIE LAB and cluster analysis, 150 varieties were divided into seven color groups: white, yellow, orange, light pink, pink, red and purple red. The rationality of grouping was confirmed in L*a*b*3D color space, a*b* 2D coordinate distribution, boxplot and visual image. [Conclusions]The statistical difference of color change between the new and old RHSCC was beyond the range of human eyes, which doesn't affect the color determination results of visual colorimetric method. However, there were overlapping intervals among the color groups of varieties by visual colorimetry of RHSCC, which was difficult to apply to strict color groups of varieties. [ABSTRACT FROM AUTHOR]

Heartwood color is a complex trait that affects the economic and aesthetic value of the wood but is highly variable. How the color of the heartwood varies spatially and temporally is poorly understood. To illustrate how heartwood color varies within a tree, two opposite aspects of wood within the same tree, representing differential growth rate, were used to model the long-short axis system jointly. The color of the heartwood on the long and the short axis was considered to be two different traits. By jointly modeling the long and short axes, the correlation was examined between aspect (spatial) and contemporaneous correlations (within aspect). Spatial and temporal correlations and their interactions describe the indirect physiological, genetic, and environmental changes in wood formation with time and position in the trunk. Spatial correlations were consistently lower than temporal correlations but were positive and significant. Between the heartwood color parameters, b* showed a relatively higher spatial correlation. The results suggest that there is a spatial correlation in the long-short axis for all color parameters and in the two surfaces. Variations between aspects were not statistically significant for any color parameter. The bivariate mixed model method revealed hidden physics behind heartwood color formation. Models need to be developed to account for both spatial and temporal dependence in studies of wood property change.

This study aimed to demonstrate and compare the accuracy of tooth shade selection due to the remineralized enamel crystal with enamel matrix derivative (EMD) in vitro. Etched enamel slices were immersed in four types of mineralization buffers for 16 h. Sodium fluoride (NaF) was added to final concentrations of 1–100 ppm with the mineralization buffer that demonstrated the highest mineralization efficiency. EMD was added to the mineralization buffer containing NaF to see if it has any remineralization capacities. The remineralized enamel crystal was analyzed by SEM and XRD. The tooth shade was evaluated by CIE L*a*b*. The results showed that, without NaF, plate-like nanocrystals were formed on the enamel surface, but with NaF, needle-like nanocrystals were formed. By adding EMD, a layer of well-compacted hydroxyapatite crystals was successfully precipitated onto the natural enamel surface. No significant differences were observed in the L* value of the mineralization surface pre-etching and after mineralization buffer containing NaF and EMD. A new method has been developed to recover the color quality of enamel, as well as to mineralize the tooth enamel by constructing hydroxyapatite crystals with mineralization buffers containing NaF and EMD on the etched tooth surface. [ABSTRACT FROM AUTHOR]

Organic and polymer encapsulated thermochromic materials have potential use as energy savers in building envelopes, due to the fact that their colour chromatic behaviour changes with temperature. External stimuli, such as solar radiation, often causes degradation in the physicochemical characteristics that impact their optical performance in real-time outdoor applications. The off-the-shelf polymeric encapsulated thermochromic dyes blended in a sodium silicate binder were prepared as coating materials on glass substrates using a dye-casting process with a film thickness of approximately 300 µm. These films have been systematically exposed to extended simulated sunlight environments at ambient conditions. The optical absorption and colour chromatic characteristics using UV–Vis spectroscopic and CIE calorimetric measurements were evaluated and compared with those of the pristine samples for photodegradation and related processes. We have also attempted to microencapsulate these thermochromic dyes and characterized via Fourier transform infrared, to understand the chemical make-up of the encapsulants for possible degradation mitigation of the dyes, and these results are also presented and discussed in this study. [ABSTRACT FROM AUTHOR]

Murals are a significant cultural heritage of humanity, and one of the conservation studies is to control the growth of microorganisms. General biocide agents can be used to preserve murals while also providing new organic carbon sources and increasing environmental pollution. In recent years, radiation technology has shown promising prospects for use in heritage protection. Five microorganisms often found in murals were irradiated with an electron beam in this study, and six mineral pigments were tested for color change, Raman spectra and pigment layer cohesion after irradiation. The result showed that irradiation at 20 kGy can basically eliminate Pseudomonas citronellolis, Bacillus sporothermodurans, Streptomyces vinaceus, and Streptomyces griseolus from the culture medium, but only inhibited the growth of Penicillium flavigenum. Lead white pigment showed a color difference of 5.56 (∆E*97) after irradiation, but lead tetroxide, azurite, malachite, ferrous oxide, and cinnabar showed no visible changes. The Raman spectra of the irradiated and unirradiated samples were basically the same. E-beam radiation did not affect the surface cohesion of the pigment layer. This preliminary work shows the potential of electron-beam technology in mural protection and provides basic research and relevant experience for the subsequent in situ mural protection work. [ABSTRACT FROM AUTHOR]

Nabulsi cheese is the dominant white-brined cheese in Jordan and neighboring countries. Although this cheese is typically prepared using sheep's milk, achieving large-scale production or attaining a specific quality involves the use of cows' milk. Nabulsi cheese is kept in >18% brine for up to 1 year at room temperature (25 °C) and then soaked in water for desalting before eating. In this study, the effects of the milk type/combination used for production (100% sheep's milk; 100% cows' milk; 1:1, 3:1, or 1:3 sheep's:cows' milk mixture), desalting (salted vs. desalted cheese), and storage time (0, 6, and 12 months) on the cheese's chemical composition directly after processing (in the salted form), texture (according to texture profile analysis "TPA"), and color (according to CIE lab color space) were assessed. The type or the combination of milk used does not affect the chemical composition of Nabulsi cheese, which was 43.35% ± 1.50 for moisture, 20.24% ± 0.59 for protein, 24.70% ± 1.53 for fat, 11.52% ± 0.60 for ash, 9.96% ± 0.44 for salt, and pH 6.43 ± 0.16. However, cheeses prepared using 100% sheep's and 100% cows' milk, respectively showed the highest (26.85%) and lowest (14.77%) yields. Desalting and milk type had the highest effects on cheese texture and color, respectively. Considering all tested parameters, mixing equal proportions of sheep's and cows' milk ensures that the Nabulsi cheese produced is similar to that produced from 100% sheep's milk, albeit with increased cohesiveness (0.52 ± 0.07 for cheese made from sheep's milk and 0.59 ± 0.05 for 1:1 sheep's: cows' milk mixture). [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the effects of spraying plants with 0.03% salicylic acid (SA), 0.7% calcium nitrate (Ca), and 0.03% salicylic acid together with 0.7% calcium nitrate (SA + Ca) on plant growth, yield, and fruit quality of peppers grown in a mineral wool substrate. The control plants were sprayed with water (C). Two red-fruited sweet pepper cultivars were used in the study: ‘Aifos’, and ‘Palermo’, which produce fruits characterized by different shapes. Biometric measurements of the plants showed a higher growth rate of pepper plants when SA and Ca were applied foliarly compared to the control. Plants treated simultaneously with SA and Ca were characterized by the highest steady-state fluorescence yield [Fs]. The relative chlorophyll content of pepper leaves was also higher in plants sprayed with SA, Ca, and SA + Ca than in plants in the control. The analysis of pepper yield showed in both cultivars the effect of foliar treatment of plants with SA and Ca and SA + Ca on increasing pepper resistance to the occurrence of Ca deficiency on pepper fruit (Blossom end rot). Pepper fruits harvested from plants treated with SA, Ca, and SA + Ca had more juicy flesh.

Bleaching of red clay is carried out by reacting iron-containing clay with the system of two reducing agents Na2S2O4, and NaBH4, in an acidic environment. The treatment process is performed with the help of ultrasonic equipment, as well as mixing operations performed at high temperature. Several physical-chemical methods such as XRF, XRD, and FTIR were used to evaluate clay samples before and after treatment. The results showed effective iron-removal in red clay. Comparison of whiteness between the processed sample and the original sample is performed by measuring parameters in the CIE L*a*b* color-system. The analysis shows that the whiteness of the treated sample reached 78.72%, showing that the treated clay has clearly improved its whiteness, and can be applied in making high-end ceramic products that require the clay with high whiteness.

The failure or debonding of CEIs (Concrete-Epoxy Interfaces) in Fiber-Reinforced Polymer concrete (FRP) systems occurs in one or a combination of three modes: CC (Cohesive failure in Concrete), CE (Cohesive failure in Epoxy), and IF (Interfacial Failure). These failure modes are usually identified, and their relationships are established by human intuition, which is prone to subjectivity. This study proposes a novel method based on image processing techniques to analyze CEI fracture surfaces and evaluate their failure modes. The failure modes of CEI fracture surfaces of specimens from a 3PB (Three-Point Bending) experiment were assessed using an HVS, CIE L*a*b*, YCbCr, or RGB color space image segmentation-based image processing technique on the preprocessed images of the CEI failure sides. A manual approach was adopted to validate the accuracy of the proposed method. Comparing the failure mode (CE) obtained using the manual and the proposed methodology, an RMSE (Root Means Square Error) of 0.19, 0.10, 0.23, and 0.26 was obtained for HVS, CIE L*a*b*, YCbCr, or RGB color space, respectively. The epoxy area selected with CIE L*a*b* color space produced the most accurate evaluation of the failure modes. This study provides an accurate method of quantifying the failure modes of CEI fracture surfaces. The methodology proposed in this study is recommended for forensic investigations to understand better the possible causes of failure in externally bounded fiber-reinforced polymers. [ABSTRACT FROM AUTHOR]

Corrosion is the process of the deterioration of metals through chemical and electrochemical reactions. The early identification of high-risk areas affected by corrosion allows time for making decisions to prevent disasters that could result from the phenomenon of corrosion. In this paper, the K-means clustering algorithm is used with various color-manipulation techniques to process and segment images of corroded metal surfaces. The goal of our research is to identify corrosion patterns in images. As an experiment, an image set of corroded surfaces demonstrating various levels of corrosion was processed. In the first phase, the images were processed with the K-means algorithm and then processed with color-manipulation techniques. The results show that this process provides relevant information regarding the surface being analyzed, successfully isolating in every test case the zone or area most affected by corrosion and highlighting the dimension of the problem. Based on our results, we recommend using the HSV technique for preprocessing images if the corroded area comprises less than 50% of the image, and an average value of k = 4 and k = 8 is recommended for obtaining significant patterns. This is important because identifying these types of patterns makes it possible for experts to make decisions without submitting these corroded metal surfaces to a second or third process or to manual analysis, and thus analytical complexity is reduced regarding time, costs, and resources. [ABSTRACT FROM AUTHOR]

Vessels with a special shape have always been a point of interest for pottery studies, especially from the perspective of the distinct functionality that these pots would have had. The ceramic typologies made for the miniature finds specific to the Middle Bronze Age in the Eastern Carpathian area include a series of such vessels attributed to the Costișa communities. Currently, the role of these pots is still under debate, being classified as ritual or special, which led to two case studies focused on investigating these miniatures. The analyzed vessels come from the Piatra Neamț—Bâtca Doamnei and Siliștea—Pe Cetățuie settlements (Neamț County), where these containers were discovered with traces of pigment or in association with colored minerals. These findings led to a series of questions related to their use, as it is known that in the Middle Bronze Age there are not many archaeological discoveries that explain the presence of pigments in the studied area. In this sense, multiplication of information was achieved by performing detailed analyses, such as optical microscopy (texture and surface details), colorimetry CIE L*a*b* (color investigation), SEM-EDX (elemental composition) and µ-FTIR (chemical compounds). The results of the interdisciplinary study led to new data on the nature of the pigment and the method of preparation, and also clues on the source of the raw material. Thus, these items illustrate the special use of miniature vessels and their probable functions. [ABSTRACT FROM AUTHOR]

The ceramic phosphate materials BaNi 2-x Co x (PO 4) 2 (x = 0, 0.5 and 1) have been elaborated for the first time by the hydrothermal process at T = 180 °C and characterized by various techniques. The structure was determined from X-ray powder diffraction using Fullprof software based on Rietveld refinement. All investigated materials crystallize in trigonal system with R 3 ‾ (no.148) space group. The BaNi 2-x Co x (PO 4) 2 (x = 0, 0.5 and 1) structure can be described as a three-dimensional framework, where two layers including edge-sharing XO 6 (X = Ni 2-x Co x) octahedra and PO 4 tetrahedra are connected by Ba2+ cations possessing twelve-fold coordination. The octahedral environment of both Ni2+ and Co2+ ions was confirmed through optical analysis. Numerous bands between 400 and 760 nm were assigned to allowed and forbidden d–d transitions of Ni2+ and Co2+ ions. CIE L∗a∗b∗ and RGB parameters were measured in order to analyse the color properties of the prepared materials. DTA/TGA analysis showed excellent thermal stability of the substituted honeycomb-lattices. Magnetic measurements revealed the presence of an antiferromagnetic order in the studied systems; for x = 0, one transition at T N = 24 K was observed. For x = 0.5 and 1, two transitions at T N and T sr were detected pointing out the spin reorientation caused by the ferromagnetic (FM) and antiferromagnetic (AFM) competition occurred when substituting between Ni2+ and Co2+ ions. FTIR spectroscopy revealed the existence of vibration modes of PO 4 tetrahedra. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, the chemical composition and spectroscopy of 38 violet-red to orange-red spinel samples were analyzed by energy dispersive X-ray fluorescence spectrometer and UV-visible spectrophotometer, based on CIE LAB color space, to explore the effects of different chromogenic ions on spinel color transition. The results show that the chroma C* is mainly controlled by the variation of color coordinates a*, and the hue angle h° is mainly controlled by the variation of color coordinates b*. Spinel can be divided into iron-bearing spinel and chromium–vanadium-bearing spinel according to their chromogenic elements, where Fe is mostly present in the form of Fe2+, which is mainly replaced with Mg2+ in tetrahedral voids, while Cr3+ and V3+ are mainly replaced with Al3+ in octahedral voids, and the level of Al content indicates the degree of isomorphism in spinel. The lightness L* of spinel decreases with increasing Cr content, and the hue h° decreases with increasing Fe and increases with increasing V content. [ABSTRACT FROM AUTHOR]

The eye's retinotopic exposure to an adapter typically produces an after-image. For example, an observer who fixates a red adapter on a gray background will see an illusory cyan after-image after removing the adapter. The after-image's content, like its color or intensity, gives insight into mechanisms responsible for adaptation and processing of a specific feature. To facilitate adaptation, vision scientists traditionally present stable, unchanging adapters for prolonged durations. How adaptation affects perception when features (e.g., color) dynamically change over time is not understood. To investigate adaptation to a dynamically changing feature, participants viewed a colored patch that changed from a color to gray, following either a direct or curved path through the (roughly) equiluminant color plane of CIE LAB space. We varied the speed and curvature of color changes across trials and experiments. Results showed that dynamic adapters produce after-images, vivid enough to be reported by the majority of participants. An after-image consisted of a color complementary to the average of the adapter's colors with a small bias towards more recent rather than initial adapter colors. The modelling of the reported after-image colors further confirmed that adaptation rapidly instigates and gradually dissipates. A second experiment replicated these results and further showed that the probability of observing an after-image diminishes only slightly when the adapter displays transient (stepwise, abrupt) color transitions. We conclude from the results that the visual system can adapt to dynamic colors, to a degree that is robust to the potential interference of transient changes in adapter content. [ABSTRACT FROM AUTHOR]

Hibiscus syriacus is a highly ornamental flowering shrub widely grown in East Asia. Its abundant flower colors mainly reflect the accumulation of anthocyanins. Classifying H. syriacus petals and identifying the relationship between flower color and anthocyanins can provide references for flower color breeding. With eight cultivars of H. syriacus as experimental materials, the floral color was described using the Royal Horticultural Society Color Chart and the CIEL*a*b* coordinate. The anthocyanin in petals was qualitatively and quantitatively analyzed by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and the relationships between flower color and anthocyanin were analyzed by using stepwise regression analysis. We divided eight cultivars of H. syriacus into five color lines: red-purple, white, violet, purple, and blue-purple, and then into two groups: purple and red-purple. The results showed that the L* had a significant negative correlation with a* and C*. A total of 52 anthocyanin components were detected in the petals of H. syriacus, including cyanidin, delphinidin, malvidin, petunidin, peonidin, and pelargonidin derivatives. Cyanidin derivatives accounted for the highest proportion, and pelargonidin derivatives accounted for the lowest proportion of the total anthocyanins. Petals of 'Pink Giant' contained the largest number of types of anthocyanin components and the highest total anthocyanin content, while the petals of 'Albus Single' contained the smallest. Petunidin-3-O-glucoside showed a significant negative correlation with L* in the red-purple group and in all cultivars, whereas it showed a significant negative correlation with b* in the purple group. Delphinidin-3-O-(6-O-Malonyl-β-D-glucoside) exhibited a significant positive correlation with a* in the red-purple group, and delphinidin-3-O-glucoside showed a significant negative correlation with L* in the purple group. Therefore, our results suggest that changing the content of these three anthocyanin components may have the potential to alter the flower color. This research provides scientific guidance and a foundation for the molecular breeding of H. syriacus cultivars with new floral colors. [ABSTRACT FROM AUTHOR]

The international trade of cotton is based on color and trash, which can be assessed by different methods. Although there are so many instruments in the market to measure the color of cotton, but still now, the visual grading of cotton color is considered to be the most impressive method. Cotton-growing countries have professionally trained persons to grade the color of cotton according to international standards. The disagreement between visual and instrumental grading is a big problem in the industry. In this research work, an improved method of visual grading system was developed, and the color diagram is represented in different color spaces. [ABSTRACT FROM AUTHOR]

Background: Neurosurgeons can assess thin red walls in a cerebral aneurysm during a microsurgical procedure, but the judgment of the color is subjective and could have a bias. This study aimed to quantitatively evaluate the aneurysm wall characteristics. Methods: In 15 unruptured cerebral aneurysms, the surface color of cerebral aneurysms, parent arteries and branches were measured using Commission International del’Eclairage L*a*b*. The values of L* (perceptual lightness), a* (red-green color characteristics) and b* (blue-yellow color characteristics) were compared with color discrimination by two independent neurosurgeons, which was classified into “red”, “yellow”, “white” and “unjudged”. Results: Significantly lower L* and higher a* values were shown in red wall points consistently judged by both neurosurgeons compared with yellow or white wall points, while b* values had no significant differences. Based on these results, a novel index, aneurysm red indicator (ARI) was developed as a ratio of a* to L* values. The ARI had a high sensitivity and specificity to discriminate red walls (0.984 and 0.986, respectively). Conclusions: ARI could be useful for evaluating thin red walls of cerebral aneurysms. The novel approach using colorimetry may contribute to future hemodynamics analyses related to the aneurysm wall characteristics.

The paper presents a concept of color trajectories as used to characterize fresco pigments and their color changes with increasing temperature. Color trajectories have shapes characteristic of certain colors or individual pigments. For 15 pigments, the minimum temperatures at which changes in their color coordinates become significant are determined. For several samples, heating can significantly change the color coordinates, but the integral color changes can be insignificant. The integral effect under heating of most samples to 740 °C is that the a* and b* color coordinates tend to zero and the lightness decreases. The exceptions are volkonskoite, the color of which becomes brighter after heating, and red lead, the lightness of which becomes greater due to the transformation of orange into light yellow. The results of this work can be used to construct an evolutionary line of real images under an increase in temperature. • Frescoes with different pigments have different minimum temperatures of color changes. • Temperature increase of some samples first leads to color changes, then almost original color is restored. • Integral color changes under heating from room temperature to 740 °C are characterized by the tendency of the a* and b* color coordinates to zero and a decrease in the L* coordinate. • For most samples with different pigments and close original colors, the color trajectories projected onto the (a*b*) plane are qualitatively similar. • At 740 °C the color of red lead (minium) becomes almost indistinguishable from the color of light ocher under normal conditions. [ABSTRACT FROM AUTHOR]

Drip irrigation is a water-saving and fertilizer-saving application technology used in recent years, with which the frequency of drip irrigation nitrogen application has not yet been determined. In order to investigate the effects of different drip irrigation nitrogen application frequencies on the processing quality of medium-gluten wheat (Jimai22) and strong-gluten wheat (Jimai20 and Shiluan02-1), a two-year field experiment was carried out. Two frequencies of water and N application were set under the same conditions of total N application (210 kg·ha−1) and total irrigation (120 mm): DIF4, consisting of four equal applications of water and N (each of 30 kg·ha−1 of N application and 30 mm of irrigation) and DIF2, consisting of two equal applications of water and N (each of 60 kg·ha−1 of N application and 60 mm of irrigation). The results showed that IF4 significantly increased protein content by 2–8.6%, wet gluten content by 4.5–22.1%, and hardness value (p > 0.05), and PC2 was considered as a protein factor; the sedimentation value was highly significantly correlated with most of the parameters of the flour stretch (p < 0.01). DIF4 improved the stretching quality, and the flour quality of Jima22 was decreased, the flour quality of strong-gluten wheats Jimai20 and Shiluan02-1 was improved, and PC1 was considered to be the dough factor. In conclusion, although the frequency of nitrogen application by drip irrigation increased the protein factor and improved the tensile quality, the flour quality was not necessarily enhanced.

Background: To investigate how rapid changes in hydration affect urine color expressed in CIE L*a*b* colorspace. Methods: This study was a two-day crossover design where subjects (N = 30) came in one visit dehydrated, after a 15 h overnight fluid deprivation, and rapidly rehydrated by drinking at least 1000 mL of water in 2 h. On the other visit subjects reported euhydrated and then rapidly dehydrated 2% by walking (3 mph) in a heat chamber (100°F, 50% humidity) for 2 h. Urine samples on both days were collected pre- and post-dehydration/rehydration. Urine osmolality, urine specific gravity, subjective urine color and objective urine color expressed in CIE L*a*b* colorspace were measured. Results: In the dehydration trial participants experienced a significant weight loss of approximately 2% of their starting, euhydrated body weight. The CIE urine color L*-value significantly decreased (−2.3 units) while the b*-value significantly increased (16 units). Subjective urine color significantly increased (1 unit). Urine osmolality increased (25 mmol/kg) and urine specific gravity increased (0.002 g/mL) between the pre- and post-dehydration conditions, however, neither of these changes were statistically significant. In the rehydration trial participants had a significant 1.5% increase in body weight after the ingestion of water. Significant increases were observed in the CIE urine color L*-value (7 units) and a*-value (1.1 units), while the b*-value significantly decreased (−24 units). Subjective urine color significantly decreased (−3 units). Urine osmolality (−600 mmol/kg) and urine specific gravity (−0.018 g/mL) significantly decreased between the pre- and post-rehydration conditions. Conclusions: Traditional markers of hydration, including urine osmolality and urine specific gravity, did not significantly change in the acute dehydration trial, suggesting that these values may not be responsive to rapid changes in hydration status. However, the CIE L*- and b*-values of urine color significantly decreased in the rapid dehydration trial and significantly increased in the rapid rehydration trial. Thus, the results of the current study suggest that urine color L*- and b*-values expressed in the CIE L*a*b* colorspace were more responsive to changes in hydration status during rapid dehydration than traditional indices of urine concentration and thus may be better markers under such conditions.

The color of wine is an important quality parameter essential for the first impression of consumers. The International Organization of Vine and Wine (OIV) recommends two methods to describe wine color: color calculation according to Glories and the determination of coordinates in the CIE L*a*b* color space. The measurement of wine color is often not feasible for winemakers because the required instrumentation is expensive and bulky. In this study, the influence of photometer settings on the calculated color was investigated based on 14 wines. Furthermore, the CIE L*a*b* and Glories system were compared using 56 red and 56 white wines. Photometer settings were found to influence the reproducibility of color determination. In addition, CIE L*a*b* system do not correlate in all wines with the Glories system and Glories probably provides less information about wine color. Using interpolation, CIE L*a*b* coordinates were calculated from single wavelength measurements taken by a small-sized and inexpensive portable analysis system, which could be used by winemakers in the future. [ABSTRACT FROM AUTHOR]

This article explores the factors that influence the color of blue iolite, which is the gem-quality variety of the cordierite mineral. The X-Rite SP62 portable spectrophotometer was used to measure color in the CIELAB color space. ED-XRF and UV–vis were used for analysis. The results show that blue iolite contains the chromophore elements Fe and Mn, but the effect on the color of iolite is not significant due to the low Mn content. The lightness L* and the hue angle h° are mostly determined by its Fe content. UV–vis spectra show that iolite has a broad absorption band near 570 nm caused by the charge transfer between Fe2+ on the octahedron and Fe3+ on the T11 tetrahedron and results in the color of blue iolite. Each different standard light source has different degrees of influence on the color parameters of iolite, and the hue angle h° is the most influenced. [ABSTRACT FROM AUTHOR]

Heartwood color is a complex trait that affects the economic and aesthetic value of the wood but is highly variable. How the color of the heartwood varies spatially and temporally is poorly understood. To illustrate how heartwood color varies within a tree, two opposite aspects of wood within the same tree, representing differential growth rate, were used to model the long-short axis system jointly. The color of the heartwood on the long and the short axis was considered to be two different traits. By jointly modeling the long and short axes, the correlation was examined between aspect (spatial) and contemporaneous correlations (within aspect). Spatial and temporal correlations and their interactions describe the indirect physiological, genetic, and environmental changes in wood formation with time and position in the trunk. Spatial correlations were consistently lower than temporal correlations but were positive and significant. Between the heartwood color parameters, b* showed a relatively higher spatial correlation. The results suggest that there is a spatial correlation in the long-short axis for all color parameters and in the two surfaces. Variations between aspects were not statistically significant for any color parameter. The bivariate mixed model method revealed hidden physics behind heartwood color formation. Models need to be developed to account for both spatial and temporal dependence in studies of wood property change. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to examine the effect of applying two different prophylaxis pastes with various protocols on the degree of bleaching and color stability in the office bleaching process with a bleaching agent containing 40% hydrogen peroxide. Material and method: The 300 teeth of 15 (9 female, 6 male) patients were included in our study, and 5 different study groups were randomly formed. The bleaching process with Ultradent Opalescence Boost (Ultradent, South Jordan, USA) was performed according to the manufacturer's instructions. Two different prophylaxis pastes, Ultrapro (Ultradent, Cologne, Germany) and Cleanic (Kerr, Rastatt, Germany), were applied with protocols determined according to the groups. The effect on color stability at 6-, 12-, and 24-month follow-up was determined using the CIE L* a* b* color system. The changes in the parameters were analyzed using the one-way ANOVA, chi-square, and Tukey test (p > 0.05). Results: The evaluation rate of the treatments was 100% at the end of 24 months. Control group 6-month ΔE (0–6) and 12-month ΔE (0–12) values were higher than 24-month ΔE (0–12) values. UU + UU, KC + KC, and UU group 6-month ΔE (0–6) values were higher than 12-month ΔE (0–12) values. In addition, 6-month ΔE (0–6) and 12-month ΔE (0–12) values were higher than 24-month ΔE (0–24) values. KC group 6-month ΔE (0–6) and 12-month ΔE (0–12) values were higher than 24-month ΔE (0–24) values. Control, UU + UU, KC + KC, UU, and KC group ΔE (1–6) values at 6 months were lower than 12-month ΔE (1–12) and 24-month ΔE (1–12) values in all groups. In addition, 12-month ΔE (1–12) values were lower than 24-month ΔE (1–24) values. According to the study data, there was no statistically significant difference between the groups according to the prophylaxis paste and prophylaxis procedure (p > 0.05). However, it was observed that whiteness decreased in all groups over time. Conclusions: Discoloration was observed at 6 months, 12 months, and 24 months after bleaching. However, at the end of 24 months, the tooth color was significantly whiter than the initial color. Clinical relevance: Pre-bleaching prophylaxis application and pre-bleaching and post-bleaching prophylaxis application have no effect on color stability. [ABSTRACT FROM AUTHOR]

The equidistance of the color space plays a significant role in determining the color difference in color transmission systems. Strictly equal contrasting color spaces can be considered only those color spaces in which equal changes in the visual perception of color are provided with an equal change in the color coordinates in this color space. Currently, the International Commission on Lighting (CIE) has adopted a number of color spaces called equal-contrast. The article presents the results of the study of color spaces adopted by CIE for equal contrast, i.e. on the differences in the thresholds of color differentiation in different areas of the color locus. The article investigated such color spaces as CIE 1931 (RGB), CIE 1931 (x, y), CIE 1960 (u, v), CIE 1976 (u*, v*), CIE LAB (a*, b*).