Surface Color Research Articles

The Toothbrushing Effects on Surface Properties and Color Stability of CAD/CAM and Pressable Ceramic Fixed Restorations-An In Vitro Study.

Pressable ceramic restorations have been introduced and investigated, and found comparable to CAD/CAM ceramic in terms of mechanical properties; however, the effect of toothbrushing on the pressable ceramic has not been thoroughly investigated. The objective of the current study was to assess the effect of artificial toothbrushing simulation on the surface roughness, microhardness, and color stability of different ceramic materials. Three lithium disilicate-based ceramics (IPS Emax CAD [EC], IPS Emax Press [EP]; (Ivoclar Vivadent AG), and LiSi Press [LP] (GC Corp, Tokyo, Japan)) were examined. For each ceramic material, eight bar-shaped specimens were prepared and subjected to 10,000 brushing cycles. Surface roughness, microhardness, and color stability (∆E) were measured before and after brushing. Scanning electron microscopy (SEM) was used for surface profile analysis. The results were analyzed using one-way ANOVA, Tukey's post hoc test, and paired sample t-test α = 0.05. The findings revealed a non-significant decrease in the surface roughness of EC, EP, and LP groups (p > 0.05), and both LP and EP have the lowest surface roughness values (0.64 ± 0.13, 0.64 ± 0.08 µm) after brushing, respectively. Toothbrushing showed a decrease in the microhardness of the three groups: EC and LP, p < 0.001; EP, p = 0.012). EP showed the lowest hardness value after brushing (862.45 ± 273.83). No significant changes (∆E) were observed in all groups (p > 0.05); however, the EC group was found to be considerably affected by color changes, in comparison to the EC and LP groups. Toothbrushing had no effect on surface roughness and color stability of all tested materials, but it decreased the microhardness. Material type, surface treatments, and glazing of ceramic materials contributed to the surface changes in the ceramic materials, necessitating further investigations in terms of the toothbrushing effect with different glazing as variables.

Seasonal Changes in the Prediction Accuracy of Hayfield Productivity Using Sentinel-2 Remote-Sensing Data in Hokkaido, Japan

In large hayfields belonging to intensive dairy systems, satellite remote-sensing data can be useful to determine the hayfield yield and quality efficiently. In this study, we compared the land survey data of hayfield yield, and its quality parameters such as crude protein and neutral detergent fiber digestibility (NDF), with the Sentinel-2 satellite image data for thirteen hayfield paddocks in Kamishihoro region, Hokkaido, Japan. Commonly used indices derived from the satellite image data, including the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), were used to assess the hayfield yield and quality. In this region, hayfields are usually harvested twice yearly, in early summer (first harvest) and late summer (second harvest). As result, the Sentinel-2 data could predict the pasture growth and quality for the first harvest better than those for the second harvest. The EVI and the index based on the bands B8a and B7 were the best predictors for the biomass and NDF for the first harvest, respectively. However, the satellite-image-based predictors were not found for the second harvest. Towards the second harvest season, the color of the hayfield surface became more heterogeneous because of the flowering of weeds and uneven pasture growth, which made it challenging to predict pasture growth based on the remote-sensing data. Our land survey approach (quadrat-based sampling from a small area) should also be improved to compare the remote-sensing data and the pasture with uneven growth.

Predicting the mechanical properties of E-glass fiber-reinforced polymer bars after exposure to elevated temperature

This paper presents the experimental investigations on the tensile, flexural, and shear performance of E-glass fiber-reinforced polymer (GFRP) bars after exposure to elevated temperatures from ambient to 500 ℃. Two types of GFRP bars with nominal diameters of 12 mm and 16 mm were directly exposed to several target temperatures for 0.5 h, and their mechanical properties were tested after cooling. The experimental results showed that the GFRP bars gradually loosened, and their surface color darkened with the increasing exposure temperature. After experiencing high temperatures, the bars’ tension, bending, and shear failure modes remained unchanged. However, their mechanical strengths showed a phased decline in three typical temperature ranges of 20 to 120 ℃, 120 to 270 ℃, and 270 to 420 ℃. In addition, no significant tensile and flexural elastic modulus degradation was observed. The measured strengths were compared with the results of several existing prediction models. A simplified model was proposed to predict the residual strength of GFRP bars after high-temperature exposure. Based on fire safety requirements, a fire-resisting reduction factor, CF, was proposed to determine the design strength of GFRP bars used in concrete slabs. For GFRP bar-reinforced concrete slabs with a cover thickness of 60 mm, the suggested CF for tensile strength and the other two strengths should be 0.65 and 0.75, respectively, to achieve structural safety after 2-h fire disasters.

Evaluation of bioactive low‐density polyethylene (LDPE) nanocomposite films in combined treatment with irradiation on strawberry shelf‐life extension

A low-density polyethylene (LDPE) film reinforced with cellulose nanocrystals (CNCs) with an encapsulated bioactive formulation (cinnamon essential oil+silver nanoparticles) was developed for preservation of fresh strawberries. Antimicrobial activity of the active LDPE films was tested against Escherichia coli O157:H7, Salmonella typhimurium, Aspergillus niger, and Penicillium chrysogenum by agar volatilization assay. The optimal condition of the films showed ≥75% inhibitory capacity against the tested microbes. Strawberries were stored with different types of films: Group 1 (control): (LDPE+CNCs+Glycerol), Group 2: (LDPE+CNCs+Glycerol+AGPPH silver nanoparticles), Group 3: (LDPE+CNCs+Glycerol+cinnamon), Group 4: (LDPE+CNCs+Glycerol+active formulation), and Group 5: (LDPE+CNCs+Glycerol+active formulation+0.5kGy γ-radiation) at 4°C for 12 days. Weight loss (WL) (%), decay (%), firmness (N), color, and total phenolics and anthocyanin content of the strawberries were measured. Results showed that the most effective LDPE-nanocomposite film for reducing the microbial growth was LDPE+CNCs+Glycerol+active formulation film (Group 4). When combined with γ-irradiation (0.5kGy), the LDPE+CNCs+Glycerol+active formulation (Group 5) significantly reduced both decay and WL by 94%, as compared to the control samples after 12 days of storage. Total phenols (from 952 to 1711mg/kg) and anthocyanin content (from 185 to 287mg/kg) increased with storage time under the different treatments. The mechanical properties, water vapor permeability (WVP), and surface color of the films were also tested. Though the WVP of the films were not influenced by the types of antimicrobial agents, they did significantly (p≤0.05) change color and mechanical properties of the films. Therefore, combined treatment of active film and γ-irradiation has potential as an alternative method for extending the shelf-life of storage strawberries while maintaining fruit quality. PRACTICAL APPLICATION: Bioactive Low-density polyethylene (LDPE) nanocomposite film was developed in the study by incorporating active formulation (essential oil and silver nanoparticle) to extend the shelf life of stored strawberries. The bioactive LDPE-based nanocomposite film along with γ-irradiation could be used to preserve fruits for long-term storage by controlling the growth of foodborne pathogenic bacteria and spoilage fungi.

First report of leaf spot on passion fruit in China, caused by Alternaria alternata.

Passion fruit (Passiflora edulis Sims), which is native to South America, is an important fruit crop in tropical and subtropical countries. Passion fruit growing areas have increased rapidly in southern China. In 2018 to 2019, circular spots on passion fruit were observed in Shangsi, Guangxi, China (21°15'N, 107°98'E). The disease occurred from June to April of the following year. The disease incidence was generally between 10% to 30%, but could reach up to 50% in purple passion fruit 'Tainong No.1'. The initial lesions on the fruits were small, with a brown center and a greasy margin, and then became sunken and lighter brown with a diameter of about 1 cm in later stages. The spots on the leaves were often surrounded by a yellow halo and turned into larger lesions after coalescence.. Five typical symptomatic fruit and leaves were collected from Shangsi county for the presumed pathogen isolation. Section of the samples were surface sterilized to isolate the fungus on potato dextrose agar (PDA) at 28°C. Five fungal isolates with similar morphology on PDA were obtained by single spore isolation. Colonies at the age of 7 days accompany with flourishing aerial hyphae, showed surface color varying from white to grey. Conidia were ovate or elliptic, light brown to brown, with 2 to 5 diaphragms, 0 to 4 longitudinal-oblique diaphragms, and mostly 8.2 to 36.7 μm × 5.4 to 15.8 μm. The morphology of the fungus resembled Alternaria alternata (Fr.) Keissl (Simmons, 2007). Each of the five isolates (SF-001, SF-002, SF-003, SF-004 and SF-005) was molecularly identified using genomic regions of 18S nrDNA (SSU), 28S nrDNA (LSU), RNA polymerase second largest subunit (RPB2), internal transcribed spacer (ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and translation elongation factor 1-alpha (TEF1) (Jayawardena et al., 2019). Nucleotide sequences of SSU (MZ275254, ON055696, ON055697, ON055698 and ON055699), LSU (MZ275253, ON062947, ON062948, ON062949, ON062950), RPB2 (MZ275251, ON055377, ON055378, ON055379 and ON055380), ITS (MW866522, MW866523, ON053451, ON053452 and ON053453), GAPDH (MZ286628, ON055381, ON055382, ON055383 and ON055384) and TEF1 (MZ275255, ON055373, ON055374, ON055375 and ON055376) were deposited in GenBank database. The LSU, GAPDH and TEF1 sequences showed 100% identity with A. alternata in NCBI (KX609773, MK683852 and MK637432, respectively). The SSU, RPB2 and ITS sequences showed 99% identity to A. alternata (U05194, MK605898 and MN856409, respectively). In pathogenicity test (Zhang et al., 2020), 3-month-old grafted 'Tainong No.1' seedlings and mature fruit were used. Five-mm-diameter mycelial plugs taken from 7-day-old PDA colonies of each of 5 isolates were placed on the leaves and fruit that were wounded with a sterilized needle to form 3 pinpricks. Sterile PDA plugs were used as control. Three plants and three fruits were used in each treatment, and the test was repeated twice. The inoculated plants and fruit were kept in plastic bags and grown in a chamber at 28℃. Typical lesions were observed on inoculated plants and fruit after 3 days, but the controls remained healthy. A. alternata was consistently reisolated from these typical lesions. Previously, leaf spot on passion fruit caused by A. alternata has only been recorded in New Zealand (Rheinländer, 2010). To our knowledge, this is the first report of A. alternata (Fr.) Keissl. causing leaf spot on passion fruit in China. The identification of the pathogen may help to take effective management strategies of controlling this disease.

Low-cost surface modification of a biomedical Zr-2.5Nb alloy fabricated by electron beam melting

• Thermal oxidation is an effective way to prepare oxide layer on a Zr-2.5Nb alloy fabricated by electron beam melting (EBM). • The morphology, phase constituents, and surface color of oxide layer change in the oxidation process. • Grain refinement significantly delays the breakaway oxidation. • A dense and black oxide layer with a hardness of 902 HV is prepared on a EBM- built Zr-2.5Nb alloy by oxidation at 600°C for 3 hours. The Zr-2.5Nb alloy with a fine microstructure consisting of α laths was successfully prepared by electron beam melting (EBM). The thermal oxidation behaviors and kinetics of the as-built, and the EBM-built and hot isostatically pressed (HIPed) Zr-2.5Nb materials in a temperature range of 450–600°C were investigated and compared with those of the alloy prepared by conventional casting and forging. It was found that the oxidation kinetics of the as-built and the forged materials followed the parabolic rate law during isothermal oxidation at 550°C, but the HIPed materials exhibited a parabolic-to-linear kinetic transition, suggesting that the larger grain sizes enhanced the oxidation. The oxide layers of all materials were composed of a large fraction of monoclinic zirconia phase ( m -ZrO 2 ) and a small fraction of tetragonal zirconia phase ( t -ZrO 2 ), and transformed from t -ZrO 2 to m -ZrO 2 with increasing oxidation time. The surface hardness of the as-built, the forged and the HIPed materials increased from 215, 204, and 188 HV before oxidation to 902, 1070, and 1137 HV after oxidation, respectively. The cross-sections of the materials showed the presence of micropores and microcracks inside the oxide layers with thicknesses ranging from 4 to 8 µm. With the oxidation temperature of 600°C and oxidation time duration of 3 h, a dense black m -ZrO 2 oxide layer with smooth surface and 902 HV hardness was obtained on the EBM as-built Zr-2.5Nb materials.

Effects of in vitro erosion on surface texture, microhardness, and color stability of resin composite with S-PRG fillers.

To evaluate the effect of acid erosion on different physical properties of resin composite with S-PRG (surface pre-reacted glass) fillers, by conducting simulations of intrinsic and extrinsic sources. Cylindrical samples (Ø6 vs. 2 mm) of a conventional nanohybrid resin composite (Forma, Ultradent) and of a nanohybrid resin composite with S-PRG filler (Beautifil II, Shofu) were exposed to erosive cycling (5 days), based on (n=12) remineralizing solution (control); 0.3% citric acid (pH=2.6); or 0.01 M hydrochloric acid (pH=2). Roughness (Ra), microhardness (KHN), and color (CIEL*a*b*, CIEDE2000, and Vita scale (SGU)) factors were analyzed at the initial and final time points, and the general color changes (ΔEab, ΔE00, ΔSGU) were calculated. Final images were obtained using scanning electron microscopy (SEM). The data were evaluated by generalized models, Mann-Whitney, Wilcoxon, Kruskal-Wallis, and Dunn tests (α=0.05). Regarding KHN, there was no difference between the groups or the time periods (p = 0.74). As for Ra, there was a significant increase in the Ra of both composites after cycling with hydrochloric acid, but only the resin composite with S-PRG filler showed a change in Ra after cycling with citric acid (p = 0.003). After cycling with citric and hydrochloric acid, the highest Ra values were found for the resin composite with S-PRG filler (p < 0.0001), corroborating the result of images (SEM) indicating loss of filler and porosities in this material. The resin composite with S-PRG filler showed higher ΔEab and ΔE00, in addition to more negative ΔSGU values and lower L* values after exposure to both acids, compared to the control (p < 0.05). The acidic conditions altered the roughness and color stability of the materials tested, pointing out that the resin composite containing S-PRG filler showed greater degradation of its physical properties than the conventional resin composite. Bioactive materials are relevant, considering that their properties interact with dental hard tissues; however, the S-PRG-based resin composite showed greater degradation under acidic conditions than the conventional resin composite.

Adaptive and Adjustable MXene/Reduced Graphene Oxide Hybrid Aerogel Composites Integrated with Phase-Change Material and Thermochromic Coating for Synchronous Visible/Infrared Camouflages

Although single-function camouflage under infrared/visible bands has made great advances, it is still difficult for camouflage materials to cope with the synergy detection spanning both visible and infrared spectra and adapt to complex and variable scenarios. Herein, a trilayer composite integrating thermal insulation, heat absorption, solar/electro-thermal conversions, and thermochromism is fabricated for visible and infrared dual camouflages by combining anisotropic MXene/reduced graphene oxide hybrid aerogel with the n-octadecane phase change material in its bottom and a thermochromic coating on its upper surface. Benefiting from the synergetic heat-transfer suppression derived from the thermal insulation of the porous aerogel layer and the heat absorption of the n-octadecane phase-change layer, the composite can serve as a cloak to hide the target signatures from the infrared images of its ambient surroundings during the day in the jungle and at night in all scenes and can assist the target in escaping visual surveillance by virtue of its green appearance. For desert scenarios, the composite can spontaneously increase its surface temperature via its solar-thermal energy conversion, merging infrared images of the targets into the high-temperature surroundings; meanwhile, it can vary the surface color from the original green to yellow, enabling the target to visually disappear from ambient sands and hills. This work provides a promising strategy for designing adaptive and adjustable integrated camouflage materials to counter multiband surveillance in complicated environments.

Effect of mild heat-moisture treatment for harvested raw paddy rice on physicochemical properties and in vitro starch digestibility of cooked rice

In this study, heat-moisture treatment (HMT) at 60 °C and 65 °C for 12 h and 18 h was applied to harvested raw paddy rice (Oryza sativa L. cv. Toyomeki), and changes in the quality characteristics and starch hydrolysis during simulated gastrointestinal digestion were investigated. The surface color of the treated rice grains was mainly caused by the period of HMT rather than the heating temperature. HMT at mild temperatures caused a minor change with no significant effect in the total starch content of the treated rice, as well as the moisture content and firmness of the cooked rice (P > 0.05). However, the resistant starch content increased with increasing HMT temperature and time, and a significant difference was found between the control and the treated rice subjected at 65 °C. The mild HMT also promoted the reduction trend of starch hydrolysis for the intact cooked rice grain, which could have health benefits. Thus, the mild HMT of raw paddy rice could be regarded as a profitable technique modifying the digestibility of cooked rice but maintaining rice sensory characteristics.

Elemental characterization of a Puma concolor fossil by non‐destructive X‐ray techniques

AbstractOver the lifetime of an animal, metabolic processes in the body maintain bone tissues in a dynamic state of equilibrium. After the death of the organism, bone tissues undergo diagenesis, an intense transformation that affects its physicochemical constitution. Although many recent works have greatly contributed to the understanding of the processes surrounding diagenesis, there is still much yet to be understood about this multifaceted phenomena. In this work, XRF and microCT were used to characterize the specimen elemental configuration and investigate the fossilization process of a recovered Puma concolor (cranium, mandible and teeth elements), found submerged in a lake in the Impossível‐Ioiô Cave System (Bahia, Brazil). MicroCT enabled the identification of the density distribution throughout the specimens, which were used as reference to XRF analyses. The XRF spectra of the analyzed specimen showed the presence of 11 elements: P, Cl, Ca, Mn, Fe, Cu, Zn, Br, Sr, Y and Hg. Yttrium counts proved to be regular throughout the specimen surface and decreased in the interface between bone surface and interior, evidencing their correspondence to sample environmental exposure. Furthermore, a correlation between fossil surface coloration, element configuration and density is presented. The relatively low presence of Fe and Y in the enamel elicits its elementary and structural preservation. The combined results contribute to the understanding of the physicochemical process of paleomastozoological fossilization, further enriching the comprehension of the process of fossilization in a submerged environment.

Effect of cigarette smoke and denture cleansers on the surface properties and color stability of CAD-CAM and conventional denture base resins.

This study aimed to evaluate the hardness, roughness, and color stability of heat- and microwave-polymerized polymethyl methacrylate (PMMA), polyamide, and CAD-CAM PMMA resins when exposed to cigarette smoke (CS) and immersed in a denture cleanser (DC). Specimens of each resins were divided into four subgroups (n=10). The DC and CS+DC specimens were immersed in a DC; the CS and CS+DC specimens were exposed to CS; and the control (C) specimens were kept in distilled water. Hardness, roughness, and color measurements were performed. DC and CS significantly affected the roughness and color of all resins (p<0.05). However, these did not affect the hardness of the CAD-CAM PMMA resin (p>0.05). The CAD-CAM PMMA resin presented the lowest roughness, highest hardness, and lowest ΔE00 values. While the roughness of all resins exposed to CS when immersed in DC decreased, the ΔE00 values of the conventional PMMAs also decreased. Although this decreases were not significant, it may be advisable to use DC for smokers to decrease discoloration and roughness especially for conventional PMMAs resins.

Application of laser on enamel surface with three types of bioactive glasses-based resin infiltrants: An in vitro study

ObjectiveThe study aimed to evaluate and compare the surface micro-hardness, roughness, color, and morphology of enamel after Er,Cr:YSGG laser irradiation, followed by application of three types of bioactive glasses-based resin infiltrants, and the samples groups were challenged with the pH cycle. MethodologyExperimental photoactivated resin infiltrants were synthesized using dimethacrylate resins, whereby three different types of bioactive glasses (BGs), i.e., 45S5, fluoridated-BG (F-BG), and borosilicate-BG (B-BG), were incorporated into the resin system. Initially, white spot lesions were created artificially on the toosth enamel surface, then irradiated with Er,Cr:YSGG laser. Then, the resin-only and BG-based resins were infiltrated on the enamel surface. All samples were pH challenged for 14 days, and the micro-hardness, surface roughness, surface morphology, and color stability (ΔE) analyses were conducted before and after the 14 days pH challenge. ResultsAfter laser irradiation, the micro-hardness was significantly high with 45S5 group compared to resin-only (p = 0.021), F-BG (p = 0.042), and B-BG (p = 0.001) groups. After the pH challenge, the micro-hardness values for all groups were reduced significantly (p ≤ 0.05). The surface roughness was least with the resin-only group and showed a non-significant difference with F-BG (p = 0.34) and significant differences with both B-BG (p = 0.005), and 45S5 (p = 0.010) groups. After the pH cycle, the roughness of all groups was increased significantly (p ≤ 0.05), except B-BG group showed a non-significant difference (p = 0.528). The B-BG group showed significantly high ΔE between day 0 and baseline compared to resin-only (p = 0.0008), F-BG (p = 0.017), and 45S5 (p = 0.029), whereas between day 14 and baseline, the lowest ΔE value was observed for B-BG (14.2 ± 2.10) and maximum for the resin-only (20.57 ± 2.47) group. The SEM images showed pitting on the surface of all resin infiltrant groups after 14 days of pH challenge. ConclusionThe morphological difference was observed after the laser irradiation on the enamel surface. The differences in micro-hardness, surface roughness, and color were observed after the application of experimental resin infiltrants and significant differences were observed after the pH challenge.

OPTIMIZATION OF LIGHTING INTENSITY IN BATAM PUBLIC LIBRARY READING ROOM

Lighting is one of the most critical components that support human life and other living creature. Poor illumination can impede users’ ability to use a building or space effectively. Library is one of the places that require good light spread so that users feel comfortable when doing activities in it. The Batam City public library is a library located on the fourth floor of the Batam City joint office. This library only has four small apertures in the form of windows for a 13.2 meter x 9 meter area, therefore sunlight cannot distribute evenly. Therefore, one solution to ensure that the library room has a suitable distribution of light is to employ artificial lighting. According to a questionnaire distributed to visitors and staff of Batam City public libraries, 82.4% of respondents believed that lighting in Batam City public libraries was still inadequate. This study used data from direct field observations, interviews with staff and library visitors, questionnaire distribution, and literature review. This research uses quantitative methods by calculating light intensity through the simulation of dialux software. Simulations were carried out in the catalogue room and the library reading room. Changing the colour of the wall surface, the furniture arrangement and the lights' placement are some experiments done to provide a good distribution of light. This study aims to evaluate and obtain lighting simulation results for the public library in Batam City that adheres to the SNI standard (300 LUX).

Effect of the material color on optical properties of thermochromic coatings employed in buildings

Thermochromic materials can adjust their formal reflectivity in response to changes in ambient temperature, so they offer a means of achieving seasonal thermal control and have been a reasonable choice to enhance the solar radiation heat in winter and lower the solar radiation heat in summer. To optimize thermochromic coatings to meet the application requirement on architectural surface color, the effect of the material color was studied on optical properties of thermochromic coatings under two transition temperatures of 25 °C and 33 °C. A measurement system was designed to analyze the reflectivity spectra and solar reflectivity of thermochromic coatings in both colored and colorless phases. Experimental results show that all samples exhibited a significant increase in reflectivity from the colored phase to the colorless phase especially in the 1300 nm–1600 nm and 1900 nm–2100 nm wavelengths. The global reflectivity of the thermochromic coatings could be increased by 3.17%–10.68% under 25 °C and 7.22%–18.23% under 33 °C. From the view of evaluating the optical properties, the purple-blue and dark-green colors are respectively the best choices for thermochromic coatings. The experimental data proposed the efficient reference for application of thermochromic materials in buildings.

A Deep Learning-Based Surface Defects Detection and Color Classification Method for Solar Cells

In recent years, solar photovoltaic-based power generation technology has become the key planning direction of many countries around the world. In the process of making solar cells, the quality inspection requirements are very particular, such as physical damages, surface scratches, broken grids and microcracks. In traditional factory production, the detection of the above defects requires professional inspectors to carry out visual inspection, which often leads to low detection efficiency, subjective assumption and fatigue, as well as some detection errors. In recent years, the rapid development of computer vision makes it possible to be used to detect the defects in solar cells. To overcome existing barriers, this paper proposes a method for detecting surface defects in solar cells based on deep neural network. Specifically, a specified image segmentation model named U-Net is developed for this purpose. By automatically segmenting little objects using the proposed recognition approach, surface defects detection can be realized. At last, we use a set of experiments on images from real scenes to verify the proposed method.

Cuticular waxes affect fruit surface color in blueberries

Societal Impact StatementIn blueberry, fruit color is one of the most important quality traits affecting consumers' choices. Both pigments and waxes impact fruit color; however, their roles have not been clearly elucidated. Here, the contributions of waxes and anthocyanins to fruit color are characterized. A higher content of β‐diketones—the second largest wax group in blueberries—determines a lighter fruit color; hence revealing that, at harvest, waxes contribute more than anthocyanins in determining variations in fruit color among blueberry varieties.Summary Fruit color is one of the major quality traits determining the marketability of fruits by affecting consumers' choices. In blueberries, although fruit surface color is mainly determined by pigments (e.g., anthocyanins), cuticular waxes also play a role in modulating the surface color, and a lighter color given by a dense wax bloom is normally preferred by consumers. This study investigated the content and composition of cuticular waxes and their roles in modulating fruit surface color in 12 (seven northern highbush, three southern highbush, and two hybrids) blueberry genotypes at harvest (H1, representing the first commercial pick, and H2, representing the second commercial pick). The ultrastructural morphology of cuticular waxes was analyzed in four selected genotypes by scanning electron microscopy. The level and profile of anthocyanins and their contributions to the color were also assessed. Total cuticular wax content ranged from 27.7 to 95.8 μg cm−2 among genotypes at H1 and decreased by an average of 23.9% from H1 to H2. Triterpenoids (62.5% of the total cuticular waxes on average) and β‐diketones (22.9% on average) were the first and second largest wax groups in all genotypes, respectively. β‐Diketones were previously proven to affect leaf surface color in wheat; in this study, their content strongly correlated with the lightness of the blueberry surface. Scanning electron microscopy revealed distinct wax morphologies among genotypes. No significant relationships were found between total or individual anthocyanin concentrations and fruit surface color. Our results suggest that, at harvest, variation in the fruit surface color among blueberry genotypes is more closely related to the content and composition of cuticular waxes than the level and profile of anthocyanins, with β‐diketones being particularly important. This study provides new insights for blueberry breeding programs aiming to improve the surface color in order to meet the market demand.

Comparison of two surface sealants on surface roughness and color stability of a commercially available denture base material – An in vitro study

Comparison of two surface sealants on surface roughness and color stability of a commercially available denture base material. Metallic discs were invested in a denture flask using dental stone to prepare a mold space. The denture base polymer and monomer were mixed in a ratio of 3:1 by volume and processed to form disc disc-shaped specimen. All the samples were finished, polished and checked for surface roughness. Sealants were applied on denture base material and cured using light-curing unit. All the 120 samples were divided into Group I(n=60) – Lucitone 199 and Optiglaze, and Group II(n=60) – Lucitone 199 and Easy Glaze. All the specimens were further subdivided into three groups based on the solution they were immersed i.e, coffee (n=20), tea (n=20), and distilled water (n=20). The specimens were checked for surface roughness and color stability for one week, one month, two months, three months, and four months. Samples were checked for surface roughness using optical profilometer and colour change using a spectrophotometer. The surface roughness of all the samples was within the normal range and tea-stained higher compared to coffee samples for color stability. The study concluded that Optiglaze is a better sealant compared to Easy Glaze with better properties like less surface roughness and good color stability of commercially available denture base materials. All groups had surface roughness less than the plaque accumulation threshold (0.20 µm). Beverages affected color stability of commercially available denture base materials after the application of two different surface sealants.

Color Constancy Based on Local Reflectance Differences

Color constancy is used to determine the actual surface color of the scene affected by illumination so that the captured image is more in line with the characteristics of human perception. The well-known Gray-Edge hypothesis states that the average edge difference in a scene is achromatic. Inspired by the Gray-Edge hypothesis, we propose a new illumination estimation method. Specifically, after analyzing three public datasets containing rich illumination conditions and scenes, we found that the ratio of the global sum of reflectance differences to the global sum of locally normalized reflectance differences is achromatic. Based on this hypothesis, we also propose an accurate color constancy method. The method was tested on four test datasets containing various illumination conditions (three datasets in a single-light environment and one dataset in a multi-light environment). The results show that the proposed method outperforms the state-of-the-art color constancy methods. Furthermore, we propose a new framework that can incorporate current mainstream statistics-based color constancy methods (Gray-World, Max-RGB, Gray-Edge, etc.) into the proposed framework.

Enlarged rete pegs with excessive accumulation of melanosomes leading to darker aging spots revealed by histomorphological measurements of internal structures of the epidermis.

Various histological studies of facial pigmented spot sites such as solar lentigo have been reported, but few studies have used quantitative indices by histomorphometric analysis of the internal structure of pigmented spot sites using non-invasive methods. In the present study, to quantitatively elucidate morphological changes in the epidermis in male, darker-pigmented spots and female, light-pigmented spots, indices that characterize the internal structure of the epidermis in pigmented spot sites were measured using in vivo confocal laser scanning microscopy (CLSM). The darkness of pigmented spots on the cheeks of 69 women and 43 men was analysed using image analysis software. The L* value was calculated from RGB values obtained from facial images. The internal structures of pigmented spots on the cheeks of 13 subjects were observed by CLSM. Various parameters were measured using CLSM images from the surface of the stratum corneum to the bottom of the dermal papillae, including the thickness of the epidermis, melanosome content, and shape of the dermal papillae. Mean ΔL* values between pigmented spots and non-pigmented areas of male subjects were significantly increased in the 40s and 50s compared with those of female subjects. Conspicuous pigmented spots increased in the 40s in male subjects and the 50s in female subjects. In CLSM observations, significant increases in the thickness of the epidermis and melanosome content were confirmed in pigmented spots compared with surrounding non-pigmented areas. In particular, melanosome content in the male subject group with dark-coloured pigmented spots increased significantly to about eight times that of non-pigmented areas, and more than double that of the male subject group with light-coloured pigmented spots. From the measurements of quantitative parameters, morphological changes in the epidermis were clearly related to the surface colour tone of pigmented spots. Darker pigmented spot sites tended to show longer rete pegs in the epidermis. Accumulation of melanosomes in epidermal basal cells could be considered to increase with the degree of elongation of rete pegs at pigmented spot sites and, thus, induce darker pigmented spots.

Wood color modification with iron salts aqueous solutions: effect on wood grain contrast and surface roughness.

Wood is a biosourced material with unique aesthetic features due to its anatomy and chemical composition. White oak wood surface color can be modified with the use of iron salts, which react with wood phenolic extractives, present as free molecules in wood porous structure. The impact of modifying wood surface color with iron salts on the final appearance of wood, including its color, grain contrast and surface roughness, was evaluated in this study. Results showed that following the application of iron (III) sulphate aqueous solutions on white oak wood surface, its roughness increased, which is due to grain raising after wetting of wood surface. The color modification of wood surface with iron (III) sulphate aqueous solutions was compared with a non-reactive water based blue stain. The contrast associated to wood grain that was expressed by the standard deviation of luminance values in wood images, also increased after application of the iron (III) sulphate aqueous solution on white oak wood surface. The comparison of contrast changes showed that wood samples stained with iron (III) sulphate on their curved surface had the highest increase in grain contrast compared to iron-stained wood showing the straight grain and to wood surfaces colored by a non-reactive water-based stain for both curved and straight grains.