Surface Color Research Articles

Finishing and polishing systems influence the roughness and color stability of acrylic and bis-acryl composite resins.

To evaluate the effect of different finishing and polishing systems on the surface roughness and color changes of bis-acryl (Protemp 4 - 3M ESPE- St. Paul, USA; Structur 3 - Voco, Cuxhaven, Germany) and chemically activated acrylic materials (Duralay - Reliance, SP, Brazil). Specimens (10 x 2 mm) thick were prepared for each material. The specimens were subjected to polishing and finishing procedures with aluminum oxide discs (Diamond Master - FGM, Joinville, Santa Catarina, Brazil) and spiral rubber disks (Sof-Lex - 3M ESPE, Germany). The control did not receive any polishing and finishing procedures. Surface roughness and color measurement values were obtained after the finishing and polishing procedures and immediately after 30 days of storage in water, coffee, and red wine. Data for each material were analyzed by One-Way ANOVA (p<0.05). The polishing with aluminum oxide discs was able to affect the initial surface roughness values of chemically activated acrylic material (p<0.05). After immersion in staining solutions, lower ∆E values were only observed for the bis-acryl composite resins compared to the control group (p<0.05). The finishing and polishing systems influenced the surface roughness and color stability of the materials tested. The chemically activated acrylic resin showed lower surface roughness and higher color stability than the bis-acryl materials. Key words:Acrylic resin, bis-acryl resin, provisional restoration.

Comparative Evaluation of Surface Roughness and Colour Stability of Four Different Composite Resins after Application of Desensitising Agents: An In-vitro Study

Introduction: Dentinal Hypersensitivity (DH) is a common clinical condition usually associated with exposed dentinal surfaces. Desensitising agents are regularly used by patients experiencing hypersensitivity, which can affect the physical properties of the existing restorative material. Aim: To evaluate the surface roughness and colour stability of four different types of composite resin restorations after exposure to a desensitising agent. Materials and Methods: The in-vitro study was conducted in the Department of Conservative Dentistry and Endodontics at Ranjeet Deshmukh Dental College and Research Centre, Nagpur, Maharashtra, India from January 2024 to March 2024. Total 56 standardised composite resin discs of size 8×2 mm thickness were prepared using four different types of composites: microhybrid, nanofilled, nanohybrid, and flowable. They were further divided into control and experimental groups based on the application of a desensitising agent, with seven samples in each subgroup. The desensitising agent was applied twice a day for three minutes for one month. Surface roughness was evaluated using a surface profilometer, and colour stability was assessed using a spectrophotometer with the Commision on Ilumination (CIE) L*a*b* formula. The data were analysed using Student’s t-test for pair-wise comparison and One-way Analysis of Variance (ANOVA), with Tukey post-hoc tests for intergroup comparison. Results: The application of a desensitising agent on the samples resulted in a significantly greater effect on the surface roughness of the experimental subgroup than their control counterparts (p≤0.05). Among all groups, the nanofilled group exhibited the lowest surface roughness (0.418±0.047), and the colour change (1.87±0.00) was clinically acceptable. However, the flowable group had the maximum colour change amongst all the other groups (3.16±0.00). Conclusion: Within the limitations of the study, nanofilled composite resin restorative material has minimal surface roughness and colour change after exposure to the desensitising agent. It can be considered the material of choice for restoration in patients with DH.

Effects of different antiviral mouthwashes on the surface roughness, hardness, and color stability of composite CAD/CAM materials.

To evaluate the effect of COVID-19 preventive mouthwashes on the surface hardness, surface roughness (Ra), and color change (ΔE) of three different polymer-based composite CAD/CAM materials (Vita Enamic (ENA), Grandio Block (GB), Lava Ultimate (LU)). A total of 100 rectangular-shaped specimens with dimensions of 2 mm × 7 mm × 12 mm were obtained by sectioning three different CAD/CAM blocks and randomly divided into five subgroups according to the 30 days of mouthwash immersion protocol as follows: Control: artificial saliva, PVP-I: 1% povidone-iodine, HP: 1.5% hydrogen peroxide, CPC: mouthwash containing 0.075% cetylpyridinium chloride, EO: mouthwash containing essential oils. Microhardness, Ra, and ΔE values were measured at baseline and after 30 days of immersion protocols. Data were analyzed using the Wald Chi-square, two-way ANOVA, and post hoc Tukey tests. The independent factors (materials and solutions) significantly influenced the microhardness and color (p < 0.001). Ra of the materials was not affected by any of the mouthwashes (p > 0.05). The microhardness and color of each material varied significantly after immersion in PvP-I and HP (p < 0.05). The highest percentage change in microhardness, Ra, and ΔE was found in LU immersed in PvP-I and HP mouthwashes, while the lowest change was found in ENA groups (p < 0.05). Within the limitations of this study, it was found that the surface hardness and color of tested polymer-based composite CAD/CAM materials are susceptible to degradation and change after 30 days of immersion in 1% PvP-I and 1.5% HP mouthwashes.

Effect of tannic/gallic acid-iron dyeing treatment on surface color and light fastness of bamboo veneer

Currently, the quest for bamboo materials with high color fastness, rich colors and environmental friendliness is rapidly rising due to its potential applications in construction, furniture and decoration. However, finding an easy-to-operate and environmentally friendly dye for bamboo is a necessary task because of the difficulty in treating the dyeing waste liquid of acid dyes and the complexity of the production process of reactive dyes.Five formulations involving metal polyphenol complexes were employed to straightforwardly produce eco-friendly dyed bamboo and the impact of various formulations on the light aging resistance of the dyed veneers was examined. The results indicated that the light resistance of bamboo veneer dyed with the solution containing only FeSO4·7H2O and tannic acid reached level 4, surpassing the undyed bamboo veneer by three levels. The mechanism of enhanced lightfastness of dyed bamboo veneer was elucidated by XPS analysis. The polyphenol iron complex serves a dual purpose: it absorbs ultraviolet rays and scavenges free radicals within the system. Additionally, it reduced the oxidation of phenolics in the substrate, transforming them into dark-colored quinone structures. This process enhanced the light-aging resistance of the finishing materials. Therefore, this work provides a simple and environmentally friendly method for changing the color of bamboo and provides a new idea for the selection of dyes for bamboo dyeing in actual production.

Color Changes in Artificially Induced Incipient Caries after Photodynamic Therapy with Different Concentrations of Methylene Blue and Toluidine Blue and Irrigation with Water and Hypochlorite.

The aim of this study was to assess the color changes in artificially induced incipient caries after photodynamic therapy (PDT) using different concentrations of methylene blue and toluidine blue, along with irrigation using water and hypochlorite. Forty-two sound human premolar teeth were used to create two artificial incipient carious lesions. One lesion was placed on the buccal surface and the other on the lingual surface. The color of these artificial incipient carious surfaces was determined using the CIE L ∗ a ∗ b ∗ color system. The teeth were then randomly assigned to 12 groups (n = 7) based on the PDT method. These methods included methylene blue with concentrations of 50, 100, and 150 µg/mL, followed by water irrigation, methylene blue with concentrations of 50, 100, and 150 µg/mL, followed by hypochlorite solution irrigation, toluidine blue with concentrations of 50, 100, and 150 µg/mL, followed by water irrigation, and toluidine blue with concentrations of 50, 100, and 150 µg/mL, followed by hypochlorite solution irrigation. The teeth underwent a colorimetry procedure again, and the resulting color changes were calculated. A three-way ANOVA was performed to analyze the effects of laser wavelength, concentration of the light-absorbing material, and irrigation solution on ΔE. The results showed that the color changes caused by toluidine blue photosensitizer at a concentration of 100 µg/mL, with both water and hypochlorite irrigation, were not noticeable to the naked eye (ΔEwater = 3.04, ΔEhypochlorite = 2.00). However, in the other study groups, the color changes were perceptible (ΔE > 3.3). There were no significant differences in ΔE between different concentrations of methylene blue and toluidine blue when using either water or hypochlorite irrigation (P > 0.05). A significant difference was observed between methylene blue and toluidine blue at a concentration of 100 µg/mL with water irrigation (P=0.006). Additionally, a significant difference was found between methylene blue and toluidine blue at a concentration of 100 µg/mL with hypochlorite irrigation (P=0.049). However, no significant differences were observed between methylene blue and toluidine blue at other concentrations with either water or hypochlorite irrigation (P > 0.05). In conclusion, tooth color in teeth with incipient caries did not change significantly after PDT using toluidine blue (the photosensitizer) at a concentration of 100 µg/mL with either water or 1% hypochlorite solution irrigation for 5 s.

Study on photovoltaic characteristics of bifacial solar panels

In the work optimum angles of orientation of solar panels with bifacial silicon solar cell, essentially different from traditional solar panels with simple silicon solar cells are experimentally defined. Are shown optimum distance from a back vertical wall and height from horizon, and also color of a horizontal surface reflecting them for achievement of high efficiency of solar panels with bifacial solar cells. Temperature factors of the main basic photovoltaic parameters of power stations with simple and bifacial silicon solar cells shown. Advantage of use of photovoltaic power stations with bifacial silicon solar cells in the hot climate conditions is revealed.

Evaluation of Shade Reproducibility and Mechanical Properties of Preshaded and Manually Shaded Monolithic Zirconia.

This study aimed to investigate the effect of manual coloring of blank monolithic zirconia blocks of four materials on their shade reproducibility, flexural strength, and surface roughness as compared with preshaded blocks of the same material. Eight disc-shaped specimens (diameter=12mm; height=2mm) and eight bar-shaped specimens (25×2×2 mm) were milled from the shaded and non-shaded blocks of the four zirconia systems: Ceramill, Kerox, White Peaks, and Dental Direkt. In total, 128 specimens were fabricated. The non-shaded specimens of each system were coloured according to A2 shade. The surface roughness (Ra) was measured using a contact profilometer. Color difference was calculated according to the CIEDE2000 formula. The bar-shaped specimens were loaded to fracture following three-point bend testing at 1 mm/minute crosshead speed. Data were analysed following one-way analysis of variance (ANOVA), and the Tukey post-hoc test (p=0.05). Manual-coloring affected the surface roughness, color difference, and flexural strength of three materials in comparison to their preshaded blocks (p<0.05). White Peaks was not affected (p>0.05). Ra values ranged from 1.1-1.9; three materials were not affected (p>0.05). Kerox preshaded blocks were the smoothest (p<0.05) but became the roughest once colored (p<0.05). White Peaks and Dental Direkt materials had preshaded blocks matching the A2 guide-tab (p>0.05). DE was perceptible and unacceptable for the preshaded and manually shaded blocks of all materials tested (ΔE>1.8). While manual coloring reduced flexural strength of Ceramill and Dental Direkt (p<0.05), flexural strength was retained by Kerox and White Peaks (p>0.05). White Peaks was not affected by the coloring technique. Coloring had negative effects on Ceramill flexural strength and color reproducibility.

Effect of novel whitening toothpastes on the surface roughness, microhardness, and color stability of anterior Extra Bleach White (XBW) composite: an in-vitro study

Effect of novel whitening toothpastes on the surface roughness, microhardness, and color stability of anterior Extra Bleach White (XBW) composite: an in-vitro study

Comparison of fracture strength, surface hardness, and color stain of conventionally fabricated, 3D printed, and CAD-CAM milled interim prosthodontic materials after thermocycling.

The purpose of this in vitro study was to investigate the fracture resistance, surface hardness, and color stain of 3D printed, CAD-CAM milled, and conventional interim materials. A total of 80 specimens were fabricated from auto polymerizing polymethyl methacrylate (PMMA), bis-acryl composite resin, CAD-CAM polymethyl methacrylate resin (milled), and 3D printed composite resin (printed) (n = 20). Forty of them were crown-shaped, on which fracture strength test was performed (n = 10). The others were disc-shaped specimens (10 mm × 2 mm) and divided into two groups for surface hardness and color stainability tests before and after thermal cycling in coffee solution (n = 10). Color parameters were measured with a spectrophotometer before and after each storage period, and color differences (CIEDE2000 [DE00]) were calculated. The distribution of variables was measured with the Kolmogorov Smirnov test, and one-way analysis of variance (ANOVA), Tukey HSD, Kruskal-Wallis, Mann-Whitney U tests were used in the analysis of quantitative independent data. Paired sample t-test was used in the analysis of dependent quantitative data (P < .05). The highest crown fracture resistance values were determined for the 3D printed composite resin (P < .05), and the lowest were observed in the bis-acryl composite resin (P < .05). Before and after thermal cycling, increase in mean hardness values were observed only in 3D printed composite resin (P < .05) and the highest ΔE00 value were observed in PMMA resin for all materials (P < .05). 3D printing and CAD-CAM milled interim materials showed better fracture strength. After the coffee thermal cycle, the highest surface hardness value was again found in 3D printing and CAD-CAM milled interim samples and the color change of the bis-acryl resin-based samples and the additive production technique was higher than the PMMA resin and CAD-CAM milled resin samples.

Extraction and Classification of Surface Color Information Using Selective LED Illumination and a Statistical Neural Network

Extraction and Classification of Surface Color Information Using Selective LED Illumination and a Statistical Neural Network

Antibacterial effect of ultrasound and β-citronellol against Listeria monocytogenes and its application in carrot preservation

This study investigated the antibacterial effects of ultrasound (US), β-citronellol (CT), and a combination of the two treatments on Listeria monocytogenes. Results showed that US or CT alone did not show apparent antibacterial effect (0.02–0.76 log CFU/mL reduction). The combined treatment showed obviously inactivate effect of L. monocytogenes, the populations of L. monocytogenes decreased by 8.93 log CFU/mL after US (253 W/cm2, 20 kHz) + 0.8 mg/mL CT treatment. US + CT treatment also had a significant (P < 0.05) antibacterial effect on isolates of L. monocytogenes from three different serotypes. In this study, the damage of US + CT on cell morphology had been observed using field emission scanning electron microscopy, while the damage to cell membranes by US + CT was observed by confocal laser scanning microscopy and flow cytometry. Meanwhile, the uptake of N-phenyl-l-naphthylamine and the absorbance at 260 and 280 nm also indicated that the combined treatment disrupted the permeability and integrity of L. monocytogenes membranes. Reactive oxygen species and malondialdehyde assays showed that US + CT exacerbated cellular oxidative stress and lipid peroxidation. In addition, the US + CT treatment reduced L. monocytogenes by 3.14–4.24 log CFU/g on the surface of carrots. Total phenolic and carotenoid contents in carrots were elevated after US + CT treatment. During storage, compared to control, US + CT did not significantly (P > 0.05) change the surface color of carrots but significantly (P < 0.05) decreased both hardness and weight, and has an impact on the sensory. This study showed that US + CT is a promising cleaning method that will provide new ideas for the preservation of fresh agricultural produce.

Color matching and color recovery in large composite restorations using single-shade or universal composites.

This study assessed the color-matching ability and color recovery of unprepared teeth when using single-shade composites and a universal composite in large restorations. Buccal and palatine surface colors of molars were measured with a spectrophotometer (CIELAB) before preparing round cavities (6 mm in diameter, 2 mm in depth). The cavities were randomly filled with a single-shade composite (Omnichroma, Diamond One, or Vittra APS Unique) or a universal composite (Filtek Universal). Color measurements of the restored cavities were taken, and overall color differences (ΔEab and ΔE00) and differences in the whitening index for dentistry (ΔWID) from baseline were calculated. Additionally, visual assessments of a color match to the surrounding enamel were performed by forty evaluators (laypersons and undergraduate students of dentistry) in a viewing booth under illuminant D65, with rating scores from 0 (no color mismatch) to 4 (not acceptable). Data were analyzed using RM or one-way ANOVA (α = 0.05). Results showed that the restorations generally exhibited whiter colors (WID ranged from 27.9 to 41.3) than the unprepared teeth (WID ranged from 15.9 to 19.3). The composite Filtek Universal demonstrated the lowest color discrepancy (ΔWID = 8.6; ΔE00 = 10.8; and ΔE00 = 6.2), and no significant differences were observed among the evaluated single-shade composites. Furthermore, all composites showed similar and adequate color matches to the surrounding enamel. However, it is important to note that despite their ability to match the surrounding enamel reasonably, none of the composites evaluated in large restorations fully recovered the color observed in unprepared teeth.

The Effect of Modeling Liquid on Color Stability and Surface Roughness of Single-Shade Composites: A SEM Study

The aim of this study; to evaluate the effects of modeling liquid use on the surface roughness and color change of single-shade universal composite resins. Total 174-cylinder shaped samples (60 roughness, 54 FE-SEM analysis, 60 color measurements) were prepared in 6 groups, (n=10) 3 of only composites, 3 of composites and modeling liquid. Composite samples were stored in coffee for 7 days and then bleached with 35% Total Blanc Office. FE-SEM analysis, color changes and roughness were measured. For statistical analysis, Two-way Anova test were used (p&lt;0,05). There is a statistically significant difference between the groups with and without modeling liquid in terms of roughness and color changes (p&lt;0,05). The highest roughness and color changes findings were observed in Essentia groups for all measurement times. When Essentia modeling is applied with liquid, the decrease in roughness and color changes is insignificant at the baseline, but the decrease is statistically significant after staining and after bleaching. FE-SEM findings show surface changes in single-shade composites after staining and bleaching. The use of modeling liquids affects the surface roughness of single-shade composites. It is also seen that the modeling liquid used on the surface of the composites protects the surface.

Testing of waste vegetable oils as color modifiers in American walnut (Juglans nigra L.) wood

American walnut (Juglans nigra L.) wood is used for veneer due to its beautifully grained and dark-colored wood. This study was conducted to test the use of plant waste oils as color modifiers on American walnut wood. As waste vegetable oils, discarded walnut, olive, corn, and sunflower oils were employed. After applying waste oils to the wooden surfaces, several surface properties (brightness, color, and whiteness index: WI*) were determined. It was observed that multivariate analysis of variance tests conducted for WI* values and color parameters were found to be statistically significant. For all vegetable waste oils, decreases were identified in L*, C*, ho, and b* parameters, as well as in WI* values and glossiness values (for all degrees and orientations). The ∆E* values were measured at 19.18 for sunflower, 22.02 for walnut, 22.65 for corn, and 19.49 for olive. Each of the discarded vegetable oils had an impact on the color of the wooden surface.

Foliar Morphological and Micromorphological Variation of Dioscorea Species in Terengganu, Malaysia

Dioscorea species are recognised for their production of tuberous roots and are referred to as "ubi" by the local population in Malaysia. The tubers of Dioscorea are commonly consumed by individuals residing in the East Coast region of Peninsular Malaysia as their primary food source. These tuberous roots are particularly abundant during the monsoon season, typically observed in local markets from October to December. Due to the availability and potential of this Dioscorea species, a study about the variation in morphological and micromorphological study of the leaves of three species of Dioscorea in Terengganu was conducted in order to identify the variation in their morphological and micromorphological characteristics. The selected species are D. esculenta (ubi itik), D. alata (ubi besar), and D. hispida (ubi gadong). The collection has been done in the Kuala Berang Terengganu area. The leaves morphological characteristics such as leaf colour, leaf type, leaf shape, leaf size, leaf margin and hairiness of adaxial and abaxial surface and shape of leaves and petiole were recorded. The morphological descriptors were suggested by the International Plant Genetic Resources Institute (IPGRI) / International Institute of Tropical Agriculture (IITA). The foliar anatomical studies of selected Dioscorea were followed by the standard tissue sectioning procedures and the observation was done by using light microscopy. The morphological study shows the variations in leaf shape, leaf base, and leaf size but they have the similarity in term of leaf margin shape and leaf attachment which is all species are petiolate. The micromorphological study shows the presence of non-glandular and uniseriate trichomes which is only obtained in the D. esculenta and D. hispida. Hence, this study contributes to the information on these species, especially for classification and identification of Dioscorea species.Keywords: Dioscorea, morphology, foliar anatomy

Effects of Immunocastration and Amino Acid Supplementation on Yearling Fallow Deer (Dama dama) Testes Development.

Forty-four fallow deer bucks (10 months old; 22.9 ± 2.4 kg) were utilized to investigate the effects of immunocastration and amino acid supplementation on testes development. Immunocastrated bucks were administered Improvac® at weeks 1, 8, and 20 of this study (control group: intact males). Starting at week 8, half of each sex received rumen-protected lysine and methionine (3:1) supplementation. At slaughter (week 37/39), body size, internal fat deposits, antler size parameters, testes weight, testes surface color, cauda epididymal sperm viability and morphology, and seminiferous tubule circumference and epithelium thickness were determined. Animals with larger body sizes, greater forequarter development, and antler growth also had greater testes development. Whilst the result of immunocastration on testes size is unexpected, testes tissue showed impaired development (atrophied seminiferous tubules), decreased sperm viability, and normal morphology. Testes tissue from immunocastrated deer was less red, possibly indicating reduced blood supply. Conversely, amino acid supplementation increased testes' redness and sperm viability, and intact males fed amino acids showed the greatest seminiferous tubule development. Thus, immunocastration may be a welfare-friendly alternative for venison production. Whilst the results support findings from the literature that testes size is not a reliable indicator of immunocastration success, this warrants further investigation in deer over different physiological development stages.

Characteristics of Black Sea dispersion of freshened and polluted transitional waters from the Dnipro-Bug estuary after destruction of the Kakhovka Reservoir dam

This study examines the characteristics of distribution of large volumes of freshened and polluted transitional waters from the Dnipro-Bug estuary across the northwestern part of the Black Sea (NWBS) that was caused by destruction of the Kakhovka HPP dam in June 2023. From June 6, 2023 to June 12, 2023 14.4 km³ of water were discharged from the Kakhovka Reservoir into the Dnipro-Bug estuary and subsequently into the sea. This volume constitutes 27% of the total annual average natural runoff of the Dnipro River (53.5 km³). During the initial days following the dam destruction water flow through the breach amounted to 40-50 thousand m³/s. The water carried a variety of pollutants into the sea that were present in the water of the Kakhovka Reservoir, in its bottom sediments, and also washed off from the flooded territories of the lower Dnipro area (more than 2000 hectares).&#x0D; The analysis of the distribution characteristics was conducted using satellite images of the sea surface color and chlorophyll a concentrations, as well as the results of hydrodynamic modeling with application of the 3-D variant of a numerical hydrodynamic model Delft3D-Flow Flexible Mesh. It was established that the plume of freshened and polluted water initially spread across the Dnipro-Bug estuarine region of the NWBS and then moved towards the sea coast of Odesa reaching it on June 9-10, 2023. Subsequently, the plume began to spread along the western sea coast and reached the Tuzlivski Limans area on June 14, 2023. After this the narrow plume of dispersed water along the sea coast began to dilute when moving towards the open sea in the form of "tongues" that had formed over the sea bottom elevations. The modeling of dispersion of a conservative neutral buoyancy admixture serving as a marker of pollution spread with the transitional waters from the Dnipro-Bug estuary showed that reduction in pollution levels took place solely due to hydrodynamic dilution (up to 60% in Odesa District of the NWBS and up to 30% in the Danube-Dniester interfluve area of the river water pollution level observed in Kherson).&#x0D; The identified characteristics were determined based on the water circulation process that formed in the Dnipro-Bug estuarine area under the influence of significant sea level gradients resulting from the inflow of large volumes of freshened transitional waters through the estuary and the Kinburn Strait during the first days, and then followed by the density currents formed at the hydrofront between the transformed river water and surrounding sea. The influence of wind conditions manifested itself in the form of spread across the NWBS of the plume of dispersed transitional water from the Dnipro-Bug estuary and the hydrofront's position and configuration. Though wind-induced currents were not dominant, they still influenced the water dynamics and distribution of concentrations of admixtures, for instance, chlorophyll a, within the freshened plume that was outlined by the hydrofront. They also promoted penetration along the coastal shallow area of transformed river water towards Odesa.

One-step preparation of color-tuned surface coatings on magnesium alloy with corrosion resistance

Nowadays, few works have been undertaken to explore the anti-corrosion coatings with tunable surface colors. In order to further expand the industrial application of magnesium alloy, a facile one-step hydrothermal method was applied to AZ91D magnesium alloy to obtain anti-corrosion coatings with diversified colors. The formation mechanism was discussed, and the corrosion resistance of the coating was assessed by electrochemical tests, immersion tests, and salt spray tests. The results show that different coating colors such as yellow, cyan, blue and red can be obtained by varying the type and concentration of reagents. The adhesion of the coating to the magnesium alloy substrate was great, and the corrosion current density of the sample with the best anti-corrosion effect was reduced by three orders of magnitude. This method has practical significance in promoting the development of surface coloring and industrial applications of magnesium alloys.

Inorganic-accelerated aging method: An efficient and simple strategy to obtain antique Chinese fir wood for the restoration of ancient wooden architecture

Ancient wooden architectures, the precious material cultural heritages of mankind, were faced with huge potential safety hazards because of the excessive aging and natural disaster. Replacing failed wood structure with antique wood is a proper and sustainable method for the repairment and reinforcement, however restricted by the lack of antique wood and mature wood antique technology. In this work, an inorganic-accelerated aging method was put forward to simulate the aging of Chinese fir wood. The as prepared antique wood exhibited a very similar surface color to that of the ancient wood, with a small chromatic aberration of only 4.4. The change of chemical compositions after inorganic-accelerated aging was also explored that hemicellulose was degraded greatly accompanied by the partly degradation of lignin and amorphous cellulose, which were similar to the nature aging process and resulted in an increase of wood crystallinity. Besides the as obtained a-W exhibited satisfactory mechanical strength, of which the bending modulus, static bending strength and compressive strength was 97.7 %, 93.4 % and 93.6 % of the ancient wood, respectively. This work provides a promising strategy for the preparing of antique wood, which is of great significance for the restoration of ancient wood architectures.

Biophilic analogous patterns for light-responsive architecture during polar night: Examining the photobiological effects of electrical lighting on surface colour configuration

This paper investigates occupants' photobiological responses of biophilic analogous patterns such as electrical lighting and surface colour configuration during dark periods in northern architecture. Biophilic design establishes that the integration of nature-inspired architectural strategies could positively impact occupants’ photobiological responses to enhance well-being in locations with limited daylight access. Photobiological responses are indicated on image-forming (IF) and non-image forming (NIF) effects. IF relates to visual outcomes, reflected on vision and visual tasks, and measured in photopic units. NIF relates to non-visual outcomes such as the biological process of circadian clock stimulation and measured in melanopic units. Limited research addresses the impact of electrical lighting combined with surface colour (SC) configurations to optimize minimum lighting requirements at photopic and melanopic levels in an architectural setting. This research therefore examines eight surface colour configurations tested under three different luminaire positions set at warm, warm-white, and white correlated colour temperature (CCT). The variables generated 72 scenarios, which were captured through high dynamic range images (HDRi), analyzed, and post-processed to display false colour maps and values of illuminance, melanopic-Equivalent Daylight Illuminance (melanopic-EDI) and spatial colour temperature. Results demonstrate the spatial diversification generated by electrical lighting to different visual tasks and circadian stimulation over a day. The study also proved that several coloured surfaces and luminaire settings can generate similar photopic and melanopic lighting conditions despite their perceived spatial colour temperature. This research highlights the photobiological adjustment of biophilic coloured lighting ambiances provided by electrical systems in northern latitudes compromised by extreme photoperiod.