Search Results (891)

Gold kiwifruits from two different farms, harvested at different times, were analysed using both non-destructive and destructive methods. A computer vision system (CVS) and a portable spectroradiometer were used to perform non-destructive measurements of firmness, titratable acidity, pH, soluble solids content, dry matter, and soluble sugars (glucose and fructose), with the goal of building predictive models for the maturity index. Hyperspectral data from the visible–near-infrared (VIS–NIR) and short-wave infrared (SWIR) ranges, collected via the spectroradiometer, along with colour features extracted by the CVS, were used as predictors. Three different regression methods—Partial Least Squares (PLS), Support Vector Regression (SVR), and Gaussian process regression (GPR)—were tested to assess their predictive accuracy. The results revealed a significant increase in sugar content across the different harvesting times in the season. Regardless of the regression method used, the CVS was not able to distinguish among the different harvests, since no significant skin colour changes were measured. Instead, hyperspectral measurements from the near-infrared (NIR) region and the initial part of the SWIR region proved useful in predicting soluble solids content, glucose, and fructose. The models built using these spectral regions achieved R² average values between 0.55 and 0.60. Among the different regression models, the GPR-based model showed the best performance in predicting kiwifruit soluble solids content, glucose, and fructose. In conclusion, for the first time, the effectiveness of a fully portable spectroradiometer measuring surface reflectance until the full SWIR range for the rapid, contactless, and non-destructive estimation of the maturity index of kiwifruits was reported. The versatility of the portable spectroradiometer may allow for field applications that accurately identify the most suitable moment to carry out the harvesting. Full article

Microbial contamination is a global concern with impacts on a variety of industries ranging from marine to biomedical applications. Recent research on hydrophilic polymer-based coatings is focused on combining antifouling polymers with nanomaterials to enhance mechanical, optical, and stimuli-responsive properties, yielding colour changing, self-healing, and super hydrophilic materials. This study combines the hydrophilic and antifouling properties of vitamin B5 analogous methacrylamide (B5AMA)-based polymers with stimuli-responsive anthocyanin-dye-loaded cellulose nanocrystals (CNCs) to develop antifouling materials with colour changing capabilities upon bacterial contamination. Poly(B5AMA)-grafted CNCs were prepared through surface-initiated photoiniferter reversible addition fragmentation chain transfer (SP-RAFT) polymerization and characterized through proton nuclear magnetic resonance (¹H-NMR), transmission electron microscopy (SEM/TEM), and X-ray photon spectroscopy (XPS) to confirm the formation of surface-grafted polymer chains. The bare CNCs and poly(B5AMA)-grafted CNCs were loaded with anthocyanin dye and evaluated for pH-dependent colour changing capabilities. Interestingly, anthocyanin-loaded CNCs demonstrated vibrant colour changes in both solution and dried film form upon bacterial contamination; however, limited colour changing capabilities of the composites, specifically in dried film form, were attributed to the enhanced dispersibility and antifouling capabilities of the polymer-coated CNCs. Full article

The sapwood and heartwood of European larch (Larix decidua Mill.) are both used in industrial applications, but they differ in structure and composition, which may lead to surface property differences. This study compared their surface characteristics (on radial and tangential sections) after sanding with aluminium oxide papers of four grit sizes (P60, P120, P180, P240). Surface roughness (Ra, Rz), wettability (contact angle with two reference liquids: water and diiodomethane, 3 and 30 s after droplet deposition), surface free energy, and colour parameters (L*, a*, b*) were analysed. Microscopic measurements were also performed to assess anatomical differences between sapwood and heartwood. The results showed no significant differences in roughness (Ra, Rz) between sapwood and heartwood. Measurement direction and sandpaper grit accounted for about 80% of variability in roughness parameters. Wettability was mainly influenced by wood area, with its effect ranging from 55% to 89% depending on measurement time. The sapwood was characterised by the lower wettability on the tangential section, while the heartwood was characterised by the lower wettability on the radial section. This was examined for the contact angle tests performed 3 s after the water droplet had been applied to the wood surface. Such dependencies were not observed after 30 s. Sapwood exhibited higher surface free energy (SFE) values than heartwood. The greatest colour change ΔE, at level 2.59, was noted for the heartwood on the radial section after sanding with P240 sandpaper. Full article

In this study, three different detox drinks were examined for their effects on the surface roughness, colour change (∆E₀₀), and transparency parameters (∆TP₀₀) of universal resin composites. One hundred twenty samples were prepared, thirty each of universal resin composites (Omnichroma, OptiShade, Filtek Ultimate Universal, and Essentia Universal). Initial values were measured. The samples were randomly divided into three subgroups and exposed to the detox drinks. Measurements were repeated after 7, 14, and 28 days of exposure to detox drinks. The highest average surface roughness values in detox drinks were obtained with Essentia Universal. It was found that average surface roughness values increased over time, and there was a significant difference between the average surface roughness values obtained during the measurement periods (p < 0.05). In all detox drinks, the lowest ∆E₀₀ values were obtained on days 7 and 14 with OM, while the highest ∆E₀₀ values were obtained on day 28. There was a significant difference in the ∆E₀₀ values of the universal resin composites tested at each time point (p < 0.05). The highest ∆TP₀₀ values were obtained from OM in all periods and all detox drinks, while the lowest ∆TP₀₀ values were obtained from FU. When the effects of resin composites, detox drinks, and time on ∆TP₀₀ were analysed, a statistically significant difference was found (p < 0.05). Manufacturers recommend using detox drinks for 28 days. However, this period of use may affect the surface properties of restorative materials. Based on these data, we recommend careful use of detox drinks to prevent adverse effects on restorative materials. Full article

Peripheral circulatory failure refers to a condition in which the blood flow through superficial capillaries is markedly reduced or completely occluded. In clinical practice, nurses strictly adhere to regular repositioning protocols to prevent peripheral circulatory failure, during which the skin condition is evaluated visually. In this study, skin colour changes resulting from pressure application were continuously captured using a camera, and supervised machine learning was employed to classify the data into two categories: before and after pressure. The evaluation of practical colour space components revealed that the h component of the JCh colour space demonstrated the highest discriminative performance (Area Under the Curve (AUC) = 0.88), followed by the a* component of the CIELAB colour space (AUC = 0.84) and the H component of the HSV colour space (AUC = 0.83). These findings demonstrate that it is feasible to quantitatively evaluate skin colour changes associated with pressure, suggesting that this approach can serve as a valuable indicator for dimensionality reduction in feature extraction for machine learning and is potentially an effective method for preventing pressure-induced skin injuries. Full article

Floral pigmentation contributes directly to reproductive strategies and fitness by shaping pollinator behaviour, and its regulation therefore represents a critical aspect of flower development. Additionally, it is a major determinant of aesthetic and economic value in the ornamental plant industry. This review explores the genetic, biochemical, and ecological bases of floral colour change, focusing on the biosynthesis and regulation of the three major classes of plant pigments: carotenoids, flavonoids (particularly anthocyanins), and betalains. These pigments, derived from primary metabolism through distinct biosynthetic pathways, define the spatial and temporal variability of floral colouration. We discuss the molecular mechanisms underlying flower colour change from opening to senescence, highlighting pigment biosynthesis and degradation, pH shifts, metal complexation, and co-pigmentation. Additionally, we address the regulatory networks, including transcription factors (MYB, bHLH, and WDR) and post-transcriptional control, that influence pigment production. Finally, we provide a comprehensive survey of angiosperm species exhibiting dynamic petal colour changes, emphasizing how these mechanisms are regulated. Full article

Medicinal mushroom production utilising rural cultivation (solid state fermentation) requires approximately six months compared to culinary mushroom production (7 days). Urban cultivation (submerged liquid fermentation) can be used as a sustainable method of producing medicinal mushroom biomass. In this study, chicken patties were fortified with liquid-fermented Ganoderma lucidum flour (GLF) and Pleurotus djamor mushroom biomass flour (PDF) at concentrations of 3%, 6%, and 9%. These were compared to a negative control (0% mushroom flour chicken patty) and a commercial patty. Chicken patties fortified with 3% PDF and 9% GLF recorded the lowest cooking loss, at 5.55% and 10.3%, respectively. Mushroom chicken patties exhibited lower cooking losses and significant changes in colour and texture compared to control samples. Notably, 3% GLF chicken patty achieved the highest overall acceptability score of 6.55 followed by 9% PDF chicken patty (6.08) (p < 0.05). Biomass flour of liquid-fermented Ganoderma lucidum (ENS-GL) and Pleurotus djamor (ENS-PD) were extracted for their endopolysaccharide and analysed for their functional properties. All elemental, FT-IR, and NMR spectroscopy analyses revealed the existence of a comparable beta-glucan polymer structure, linkages, and absorptions when compared to the Laminarin standard. In addition, ENS-GL also proved to possess higher antimicrobial activities and significant antioxidant levels (DPPH-scavenging activity, ferric reduction potential and total phenolic content) compared to ENS-PD. Overall, this study revealed that sustainable liquid-fermented Ganoderma lucidum, a medicinal mushroom, outperformed Pleurotus djamor, a culinary mushroom, as a potential alternative flour for combating hunger in the future. Full article

This study investigates the impact of mild steaming (105 °C and 120 °C for 12 h) on the colour characteristics and chemical stability of beech wood (Fagus sylvatica L.) during natural indoor ageing. Untreated and steamed samples of mature wood and false heartwood were analysed for CIELAB and CIELCh colour parameters (L*, a*, b*, C*, h°) and chemical changes using ATR-FTIR spectroscopy. Steaming resulted in a significant decrease in lightness (L*) and increased a*, b*, and C* values, producing darker and more saturated reddish-brown tones. It also reduced the visual differences between mature wood and false heartwood, enhancing colour uniformity. During the light-induced ageing period, steamed wood—particularly at 105 °C—exhibited improved colour stability, maintaining chroma and hue more effectively than untreated samples. Statistically significant interaction effects between treatment, time, and tissue type revealed that the ageing-related colour changes were jointly influenced by thermal modification and the anatomical characteristics of the wood. In the FTIR spectra, the most pronounced changes were observed in the absorption bands of the aromatic skeleton and carbonyl groups (1504 and 1732 cm⁻¹). These findings confirm that mild steaming alters the original aesthetic properties and colour of beech wood when exposed to an indoor environment. Full article

Serra da Estrela cheese (a raw ewe’s milk) ripened for 45 days was treated at 600 MPa for 6 min (P1) and at 450 MPa for 6 (P2) and 9 min (P3) and kept in refrigerated storage for 15 months. Lactobacillus and Lactococcus viable cell numbers were reduced in 3.2–3.6 and 2.7–3.6 log cycle units, respectively. Lower reductions were verified for total aerobic mesophilic and Enterococcus viable cell numbers in cheeses treated at 450 MPa (2.4–2.5 and 1.2 log reductions, respectively). In HPP cheeses, yeasts and moulds were below the enumeration limit up to 6 months of storage, but at 15 months 3.6–4.2 log cfu/g were quantified in all cheeses, while Enterobacteriaceae were inactivated to below the quantification limit. The increment of pressure treatment caused a greater impact on the microbiota’s viability than the increase in time under pressure. During storage, minor total colour differences were determined for HPP P3 cheese surface relative to control cheeses, Ch_C, at 45 days of ripening. HPP can thus be a good process to apply after cheese manufacture, since it offers a good potential to render raw-milk cheese microbiologically safer, with minimal changes in quality. Full article

This study developed chitosan-based active edible coating formulations with antioxidant and antimicrobial properties exhibited by oregano and cinnamon leaf essential oils (EOs) to extend the shelf life of fresh-cut ‘Braeburn’ apples. The primary coating consisted of chitosan (1.5% w/v), ascorbic acid (2% w/v), and citric acid (2% w/v). Oregano (0.06 and 0.15% v/v) and cinnamon leaf (0.06 and 0.1% v/v) EOs were added to the primary coating. The coated apple slices were stored for 9 days at 4 ± 1 °C. Changes in weight loss, water activity, titratable acidity, total soluble solids content, polyphenol oxidase (PPO) activity, firmness, colour, visual appearance, surface morphology, and microbial activity were measured on days 2 and 9. The results revealed that the control samples deteriorated rapidly during storage. However, higher concentrations of EOs reduced moisture loss, water activity, and acid conversion but slightly impacted visual appearance. The coatings effectively inhibited the PPO activity through storage. The formulation with 0.1% cinnamon leaf EO may be considered a viable candidate for application as a coating material, followed by the formulation containing 0.06% oregano EO, maintaining the optimum quality parameters of fresh-cut apples. Chitosan-based coatings with added EOs can be a promising alternative for maintaining fresh-cut apple quality during storage. Full article

Dyed wool samples and lake pigments prepared from the same dyestuffs were exposed to light over the course of 14 months. Brazilwood or sappanwood, cochineal, madder, and weld were used for both wools and pigments, with the addition of dyer’s broom, indigo, and tannin-containing black dyes for the wools and eosin for the pigments. The wools were dyed within the MODHT European project on historic tapestries (2002–2005), using recipes derived from fifteenth- to seventeenth-century sources. The pigments were prepared according to European recipes of the same period, or using late nineteenth-century French or English recipes. Colour measurements made throughout the experiment allowed for overall colour difference (ΔE₀₀) to be tracked and half-lives to be calculated for some of the colour changes. Alterations in the samples’ hue and chroma were also monitored, and spectral information was collected. The results showed that, for both textiles and pigments, madder is the most stable red dye, followed by cochineal, and then brazilwood. Eosin was the most fugitive sample examined. Comparisons of textile and lake samples derived from the same dyestuff, whether red or yellow, indicate that the colourants are more stable when used as textile dyes than in analogous lake pigments. Full article

The impact of fire on natural stone structures is a critical concern, particularly for historical buildings. This study examines the residual mechanical properties of sandstone after exposure to high temperatures. Cylindrical sandstone samples were heated to temperatures up to 900 °C and subsequently tested under uniaxial compression. The results indicate that mechanical degradation becomes significant beyond 460 °C, with compressive strength decreasing by up to 43% at 900 °C. Young’s modulus also declined substantially, while axial strain increased, indicating progressive structural weakening. Additionally, visible colour changes suggest mineralogical transformations. These findings provide essential insights into the fire-induced deterioration of sandstone, offering valuable guidance for the preservation and restoration of historical stone structures. Full article

Background/Objectives: The colour changes related to inflammation have yet to be quantified despite the fact that the intensification of gingival colour is one of the cardinal signs of gingival inflammation. We aimed to (1) assess the effect of periodontal treatment on gingival colour according to biotype and initial degree of inflammatory severity and (2) identify the relationship between the plaque index and gingival colour and compare the colour of moderately or severely inflamed gums to the colour of gums with mild inflammation. Methods: Forty-three participants with visual signs of inflammation were included in the study. CIELAB colour coordinates were measured using a spectrophotometer at the distal papilla, free gingival margin, middle zone of the attached gingiva, and mucogingival line proximate to the maxillary central incisor pre-treatment and four weeks post treatment with periodontal debridement. Each participant’s gingival biotype, plaque and gingival indices, age, and gender were also recorded. Results: The biotype and plaque index were both found to influence the colour of inflamed gums, albeit only the a* coordinate in two of the zones examined (the distal papilla and free gingival margin). Statistically significant differences were also found between the a* coordinates of participants with and without plaque at the distal papilla and the free gingival margin. The severity of inflammation also influenced the L* coordinates of gingival colour (p < 0.001) in all participants in all four zones examined. Periodontal treatment only affected the L* coordinate of gingival colour at the distal papilla and the free gingival margin. Conclusions: When gingival inflammation occurs, participants with thin biotype and plaque have redder gums, and moderately or severely inflamed gingiva have a visually perceptible darker colour. Periodontal treatment significantly increases the lightness of the distal papilla and the free gingival margin. Further, periodontal treatment creates a perceptible colour change in all zones under study, which is not dependent on either the patient’s biotype or initial severity of inflammation. Clinical Significance. Digital spectrophotometric analysis provides a valuable technological enhancement to quantify gingival colour and record changes in gingival colour during the course of periodontal treatment. Regardless of the initial severity of gingival inflammation, a perceptible increase in the L* coordinate (gums become visibly lighter) can be expected after periodontal treatment. Regardless of the initial severity of inflammation, a perceptible increase in the L* coordinate can be expected (gums become visibly lighter) after treatment. Full article

Recently, the development of nanoparticle pigments has attracted interest in chemical preparation due to their potential functional properties, such as phosphate-based pigments. The present research focuses on the feasibility of synthesising the BaCr₂(P₂O₇)₂ pigment under hydrothermal conditions. The effect of the microstructural features of ceramic pigments (the crystalline structure, morphology, and particle size) on their optical properties (colour and reflectance) was also studied. The BaCr₂(P₂O₇)₂ compound was prepared in different fluid media, including water and NaOH solutions (0.5–1.0 M), at several reaction temperatures (170–240 °C) and intervals (6–48 h). The single-phase BaCr₂(P₂O₇)₂ did not crystallise without by-products (BaCr₂O₁₀, BaCr₂(PO₇)₂) in water and the alkaline solutions, even at 240 °C for 48 h; in these fluids, the ionic Cr³⁺ species oxidised to Cr⁶⁺. In contrast, the BaCr₂(P₂O₇)₂ single-phase crystallisation was favoured by adding urea as a reductant agent (25.0–300.0 mmol). Monodispersed BaCr₂(P₂O₇)₂ fine particles with a mean size of 44.0 nm were synthesised at a low temperature of 170 °C for 6 h with 0.5 M NaOH solution in the presence of 50.0 mmol urea. The phosphate pigment particle grew to approximately 62.0 nm by increasing the treatment temperature to 240 °C. A secondary dissolution–recrystallisation achieved after 24 h triggered a change in the particle morphology coupled with the incrementation of the concentration of NaOH in the solution. The pyrophosphate BaCr₂(P₂O₇)₂ pigments prepared in this study belong to the green colour spectral space according to the CIELab coordinates measurement, and exhibit 67.5% high near-infrared (NIR) solar reflectance. Full article

Traditional park designs no longer meet the diverse needs of young users amid rising visitor numbers and environmental challenges. Exploring the impact of mountain city parks on youth is crucial, yet localised studies on their spatial perceptions in such unique environments are lacking. Landscape design based on spatial perception evaluation offers a promising approach for renewing mountain parks to address these complex needs. Therefore, a pilot study was conducted in Chongqing’s Pipa Mountain and Eling Parks, involving questionnaire surveys and on-site spatial data collection. Using principal component analysis to select the visual and auditory indicators most related to environmental satisfaction in the overall park and various types of gathering spaces, the results showed that the first principal component of the visual environment in the entrance platform and key nodes (r = 0.41, r = 0.45), as well as the first principal component of the auditory environment in the entrance platform, path platform, and elevated points (r = 0.67, r = 0.85, r = 0.68), all showed significant positive correlations with environmental satisfaction (p < 0.01). Moreover, naturalness and aesthetics were identified as the main factors influencing environmental satisfaction. A random forest model analysed nonlinear relationships, ranking spatial factors by importance. Simultaneously, SHAP analysis highlighted the effects of key factors like elevation changes, green view index, colour diversity, and natural elements. Elevation changes were positively correlated with satisfaction at elevated points but showed a negative correlation in the overall park environment and other gathering spaces. This study explored space-perception dynamics in mountain city parks, proposing strategies to improve environmental quality in various gathering spaces and the park. These findings support creating liveable mountainous environments and guide “human-centred health,” quality enhancement, and sustainable development in renewing mountain city parks. Full article