Marked Color Research Articles

Development of a Machine-Learning-Based Tool to Predict Retroreflectivity of Pavement Markings Across the U.S.

Retroreflectivity plays a crucial role in pavement markings as it enhances nighttime visibility for drivers. Yet, owing to budget constraints, many U.S. state agencies rarely monitor the retroreflectivity of their markings, and instead, restripe markings based on visual inspection or fixed schedule. To address this issue, Federal Highway Administration (FHWA) announced a new final rule, effective September 6, 2022, that establishes a new minimum standard for pavement marking retroreflectivity. This rule also requires state agencies to implement a method within four years for maintaining pavement marking retroreflectivity at or above minimum levels. The ultimate objective of this research was to help state agencies comply with this new rule by developing a new decision-making tool for predicting retroreflectivity of pavement markings for up to three years using only measured initial retroreflectivity (at installation date) and other readily available project data (marking color, marking type, etc.). As such, data from National Transportation Product Evaluation Program (NTPEP) were retrieved and analyzed using six robust machine learning algorithms, and the algorithm yielding highest accuracy was selected to be incorporated into the proposed software. Findings indicated that random forest demonstrated best performance among the six algorithms. As expected, prediction accuracy decreased over time. Within the first year, random forest models successfully predicted retroreflectivity with a coefficient of determination (R2) of 0.97 and root mean square error (RMSE) of ± 31.12 mcd/m2/lux. Within the second and third years, R2 and RMSE were 0.92/±43.7 mcd/m2/lux, and 0.91/±36.0 mcd/m2/lux, respectively, which are more accurate as compared with previous studies.

A Template Method Leads to Precisely Synthesize SiO2@Fe3O4 Nanoparticles at the Hundred-Nanometer Scale.

Constructing photonic crystals with core-shell structured nanoparticles is an important means for applications such as secure communication, anti-counterfeiting marking, and structural color camouflage. Nonetheless, the precise synthesis technology for core-shell structured nanoparticles at the hundred-nanometer scale faces significant challenges. This paper proposes a controlled synthesis method for core-shell structured nanoparticles using a template method. By using 100 nm diameter silica nanospheres as templates and coating them with a ferroferric oxide shell layer, SiO2@Fe3O4 core-shell structured nanoparticles with regular morphology and good uniformity can be obtained. The study experimentally investigated the effects of feed amount, modifiers, temperature, and feed order on the coating effect, systematically optimizing the preparation process. Centrifugal driving technology was used to achieve structural colors in the visible wavelength range. Additionally, the method successfully created well-defined and uniform core-shell structured nanoparticles using 200 nm diameter silica nanospheres as templates, demonstrating that this controllable synthesis method can effectively produce core-shell structured nanoparticles over a wide range of particle sizes. The template method proposed in this paper can significantly improve morphological regularity and size uniformity while effectively reducing the preparation cost of core-shell structured nanoparticles.

Determining the efficacy of visual inspections at detecting non-biosecurity-compliant goods.

Examination of imported commodities by trained inspectors searching for pest organisms is a common practice that phytosanitary regulatory agencies use to mitigate biosecurity risks along trade pathways. To investigate the effects of target size and color on the efficacy of these visual assessments, we affixed square decals to polystyrene models of mandarins. Sample units of 100 model fruit containing up to 10 marked models were examined by inspectors. Six sizes in six shades of brown were tested across two prevalence levels. The experiment consisted of five inspection rounds where 11 inspectors examined 77 sample units within an allocated time. The probability that decals were detected increased with mark size and color contrast. Smaller, low-contrast marks were mainly missed. The prevalence rate did not affect the detectability. Through the experiment, the false-positive rate dropped from 6% to 3%, whereas false-negative rates were constant throughout. Large, dark targets were readily found with a mean recall of >90%, whereas small, pale marks had a mean recall of 9%. Increased experience made inspectors more competent at recognizing decals, reducing the false positive rate. However, constant false-negative rates indicate that experience did not prevent inspectors from overlooking targets they could not perceive.

Utility of Second-look Ultrasonography in Distinguishing BI-RADS 4 Calcifications Detected on Mammography: An observational study.

This study aimed to assess the utility of second-look ultrasonography (US) in differentiating breast imaging reporting and data system (BI-RADS) 4 calcifications initially detected on mammography (MG). BI-RADS 4 calcifications have a wide range of positive predictive values. We hypothesized that second-look US would help distinguish BI-RADS 4 calcifications without clinical manifestations and other abnormalities on MG. This study included 1622 pure BI-RADS 4 calcifications in 1510 women (112 patients with bilateral calcifications). The cases were randomly divided into training (85%) and testing (15%) datasets. Two nomograms were developed to differentiate BI-RADS 4 calcifications in the training dataset: the MG-US nomogram, based on multifactorial logistic regression and incorporated clinical information, MG, and second-look US characteristics, and the MG nomogram, based on clinical information and mammographic characteristics. Calibration of the MG-US nomogram was performed using calibration curves. The discriminative ability and clinical utility of both nomograms were compared using the area under the receiver operating characteristic curve (AUC) and the decision analysis curve (DCA) in the test dataset. The clinical information and imaging characteristics were comparable between the training and test datasets. The bias-corrected calibration curves of the MG-US nomogram closely approximate the ideal line for both datasets. In the test dataset, the MG-US nomogram exhibited a higher AUC than the MG nomogram (0.899 vs 0.852, P = .01). DCA demonstrated the superiority of the MG-US nomogram over the MG nomogram. Second-look US features, including ultrasonic calcifications, lesions, and moderate or marked color flow, were valuable for distinguishing BI-RADS 4 calcifications without clinical manifestations and other abnormalities on MG.

Road marking defect detection based on CFG_SI_YOLO network

Existing road marking detection primarily focuses on the direction, position, and color of road markings. However, clear and accurate road markings directly impact issues such as directional guidance, lane selection, speed limits, and parking positions. Therefore, we introduce the CFG_SI_YOLO model for road marking defect detection. This model introduces a multi-channel CoordConv module, which enhances the network's focus on fine details based on the distribution characteristics of road markings defect. This helps prevent the loss of road marking information caused by model compression and pooling operations; Moreover, the model introduces the Focal-EIoU loss function to address the issue of imbalanced samples between easy and difficult cases. Additionally, the GELU activation function is incorporated to prevent gradient explosions, enhance the network's non-linear expressiveness, and improve the detection accuracy of the model. Finally, we add a similarity attention module to enhance the network's focus on the target, reduce interference from other objects, and mitigate false detection defects caused by inter-class similarity. Experiments conducted on a self-made dataset containing various types of road markings have shown that our approach achieved Precision, Recall, F1, IoU, and mAP of 85.7%, 85.8%, 85.7%, 75.1% and 82.8%, respectively. These results are significantly better than other methods, confirming the effectiveness and feasibility of our approach. Our code and results can be found on https://github.com/ly6660/Road_marking_line_code_data.

Impacts of Emergency Vehicle Marking Characteristics and Wearable Lights on Driver Responses

Retroreflective markings provide important visual information to drivers about emergency vehicles and the incidents at which they are working. A stationary outdoor field study to investigate the impacts of emergency vehicle marking color, retroreflectivity level, and spatial patterns on drivers’ ability to see nearby emergency responders was carried out. The study also examined the impacts of a wearable flashing light-emitting diode (LED) light. Based on the results, agencies should use materials with higher levels of retroreflectivity carefully, especially when they will be covering large-area vehicle surfaces. Limiting the maximum retroreflectivity level to no greater than American Society for Testing and Materials Type III may help lessen negative impacts of bright reflective materials on drivers’ ability to see emergency responders. As long as the average reflectivity of different color combinations is similar to that of red and yellow reflective markings, chevron patterns with those color combinations will not reduce emergency responder visibility. Outline patterns of reflective markings on vehicles performed similarly at night to patterns covering most of the vehicle surface. The effectiveness of using high-retroreflectivity materials in an outline pattern in combination with lower- (or non-) retroreflectivity materials elsewhere on the surface should be studied. Wearable flashing LED lights can make emergency responders easier to see at night, provided they do not increase glare to approaching drivers.

Effect of carbamide peroxide on biomechanical properties of vacuum-formed retainers: A split-mouth randomized controlled trial

ObjectiveTo investigate the effect of tooth whitening on biomechanical properties of vacuum-formed retainers (VFRs). MethodsUsing a split-mouth, randomised controlled trial design, thirty participants were randomly allocated to receive whitening on either the upper or the lower arch, using 10 % carbamide peroxide for two weeks. Biomechanical properties such as hardness, tensile strength, and surface roughness were assessed two weeks after whitening was completed. ResultsTensile strength of the whitening arch (mean ± SD: 40.93 ± 3.96 MPa) was significantly lower than that of the control (47.40 ± 5.03 MPa) (difference 6.47 MPa, 95 % CI 4.51 – 8.42, p < 0.001). Hardness and internal roughness of the whitening arch (VHN = 14.63 ± 2.29 N/mm2 and Ra = 1.33 ± 0.35 µm, respectively) were significantly greater than those of the control (12.22 ± 1.86 N/mm2 and 0.96 ± 0.29 µm, respectively) (differences 2.41 N/mm2, 95 % CI 1.56 – 3.25, p < 0.001 and 0.37 µm, 95 % CI 0.23 – 0.51, p < 0.001, respectively). The whitening arch showed greater tooth colour change (ΔE = 6.00 ± 3.32) than the control (ΔE = 2.50 ± 1.70) (difference = 3.50, 95 % CI 2.43 – 4.56, p < 0.001). ConclusionsBased on this short-term study, marked tooth colour change was achieved by whitening with VFRs as the whitening trays, but this changed the VFRs’ biomechanical properties, including a decrease in tensile strength and an increase in hardness and internal roughness. Clinical significanceThe application of carbamide peroxide in VFRs may compromise their mechanical properties.

Tailoring the optical and mechanical properties of cellulose nanocrystal film by sugar alcohols and its pH/humidity-responsive behavior

Cellulose nanocrystals (CNC) have gained widespread attention in intelligent food packaging because of their iridescent optical properties. Here, we report a CNC composite film employing CNC, sugar alcohols (e.g., maltol, erythritol, mannitol, sorbitol, and xylitol) and natural pigment anthocyanins, which has a special iridescent color that can be used as a pH and humidity sensor. The effects of five sugar alcohols with different addition ratios on the structural, optical, and mechanical properties of the CNC films were investigated. The results demonstrated that the addition of sugar alcohol made composite films exhibiting a red-shift of λmax, a more uniform color in visual observation, and a larger pitch. Among them, the CNC-mannitol composite film with a ratio of 10:1 exhibited the best mechanical properties, possessing a tensile stress strength of 57 MPa and toughness of 137 J/m3. Subsequently, anthocyanins were incorporated to this composite film, which showed a marked color change along with the pH from 2 to 12 and exhibited a reversible color change from red to transparent upon a relative humidity change from 35 % to 85 %. Overall, such multi-environment-responsive iridescent films with excellent mechanical properties have a great potential for use in intelligent food packaging applications.

Rapid and reversible humidity-dependent colour change by water film formation in a scaled springtail.

Colour is often not a static trait but can change over time either through biotic or abiotic factors. Humidity-dependent colour change can occur through either morphological change (e.g. to feather barbules in birds) or by the replacement of air by water causing a shift in refractive index, as seen in arthropod multi-layer cuticles or scales. The scaled springtail Lepidocyrtus cyaneus has scales that produce colour largely via thin film interference from their lamina. We observed a marked colour change from golden to violet/purple coloration in humid conditions. Light microscopy, micro-spectrophotometry, contact angle goniometry and optical modelling indicate that the formation of a thin film of water on top of the hydrophilic scales increases their laminar thin film thickness, causing a shift towards violet/purple colour. Evaporation of the water film causes the metallic golden colour to return. This constitutes a remarkably rapid colour change (in the order of seconds), only limited by the speed of water film condensation and evaporation, that may serve as inspiration for new dynamically coloured materials and sensors.

Effect of the alcoholic strength of unaged wine distillates on the final composition of Brandy de Jerez aged in Sherry Casks®

Brandy is a spirit obtained from distilled wine that has an alcohol content equal to or greater than 36 % ABV (Alcohol by Volume). It undergoes an ageing process in oak wood casks with a capacity of up to 1000 L for a minimum of six months. During this process, a series of physicochemical and sensory changes take place that confer the initial wine distillate with a series of improvements to its sensory profile. Such changes are mainly determined by the intrinsic characteristics of the wood and by those associated with the manufacturing process of the casks. The previous use of the casks, ageing time and the alcoholic strength of the wine distillate are also important factors, among others. The casks, which will have previously contained some type of Sherry wine (such as Fino, Amontillado, Oloroso and Pedro Ximénez), are known as Sherry Casks® and they must be used in the production of Brandy de Jerez. During the ageing of Brandy de Jerez, Sherry Casks® contribute to the final brandy via the compounds that are both inherent to the wood they are made of and from the wine that they initially contained and that were retained in the wood pores. The alcohol content of the wine distillate to be aged significantly affects not only the quality of the brandy, but also the financial cost of the process. This study aimed to determine the influence on brandy of the alcoholic strength of wine distillates aged in static ageing systems using Sherry Casks®. Specifically, we assessed the physicochemical composition and sensory profile of Brandy de Jerez made from wine distillates with three different alcoholic strengths (40 %, 55 % and 68 % ABV) and aged for 24 months. The Brandy de Jerez with lower alcoholic strengths (40 % - 55 % ABV) were found to contain a higher concentration of polyphenolic compounds deriving from the wood as well as from the constituents of the cask-seasoning Sherry wine. The brandies with higher alcoholic strengths exhibited a marked colour change, while the 40 % and 55 % ABV brandies were perceived to have the best sensory characteristics.

Gelatin/poly(vinyl alcohol)-based dual functional composite films integrated with metal-organic frameworks and anthocyanin for active and intelligent food packaging

Innovative active and pH-colorimetric composite films were fabricated from gelatin/poly(vinyl alcohol) (Gel/PVA) integrated with copper-based metal-organic frameworks (Cu-MOFs) and red cabbage anthocyanin (RCA). The incorporation of Cu-MOFs improved the tensile strength, water resistance, and UV shielding properties of the developed composite films. The addition of anthocyanins and 3 wt% Cu-MOFs endowed the polymer matrix with excellent antioxidant (100 % against ABTS and DPPH radicals) and antibacterial (against Gram-positive and Gram-negative foodborne pathogenic bacteria) functions. The fabricated composite films exhibited significant color change at alkaline conditions of pH 7–12 and a marked color change upon exposure to ammonia. The designed indicator films used for shrimp freshness tracking and a visual color change from pink (for fresh shrimp) to green (for spoiled shrimp) was observed during storage at 28 °C for 24 h. The potential applications of the engineered composite films were studied by shrimp packaging, and the quality parameters of packaged samples were monitored during storage. The synergistic effects of adding anthocyanins and MOF nanostructures works for better product freshness preservation and responds well to shrimp spoilage level, introducing novel active and intelligent packaging options for practical smart packaging applications.

Effects of Debranching Conditions and Annealing Treatment on the Formation of Starch Nanoparticles and Their Physicochemical Characteristics.

Starch nanoparticles (SNPs) have unique attributes that make them suitable for specific applications. In this study, we assessed the optimum conditions for the fabrication of SNPs from the rice starches of low- (TCSG2) and medium-amylose rice lines (TK11) using pullulanase debranching combined with annealing treatment and evaluated their physicochemical and digestion properties. The highest crystalline SNP percent recoveries of 15.1 and 11.7% were obtained from TK11 and TCSG2, respectively, under the following debranching conditions: 540-630 NPUN/g, pH 5.0, 60 °C, and 12 h. The percent recovery of the crystalline SNPs by the combined modification of the debranching and the annealing treatment with an extended annealing incubation prepared from TK11 and TCSG2 was significantly increased to 25.7 and 23.8%, respectively. The modified starches from TK11 had better percent recovery of the crystalline SNPs than those from TCSG2. They exhibited a higher weight-average molecular weight (Mw) and a broader/bimodal molecular weight distribution with a higher polydispersity (PDI) (Mw = 92.76-92.69 kDa; PDI = 4.4) than those from TCSG2 (Mw = 7.13-7.15 kDa; PDI = 1.7). Compared to the native counterparts, the color analyses showed that the modified starches from TK11 and TCSG2 exhibited decreased brightness (L*)/whiteness index (WI) values with marked color difference values (∆E) ranging between 6.32 and 9.39 and 10.67 and 11.32, respectively, presumably due to the protein corona formed on the surface of SNPs which induced the browning reaction during the treatments. The pasting properties revealed that the modified starches displayed restricted swelling power with extremely low pasting viscosities, reflecting that they were highly thermally stable. The modified starches, especially those treated with an extended annealing incubation, exhibited marked decreases in the rate and extent of digestion and estimated glycemic index due to the honeycomb-like agglomerates comprising an assembly of densely packed SNPs. The results could provide helpful information for the preparation and characterization of the crystalline SNPs for potential applications such as emulsion stabilizers for Pickering emulsion and health-promoting ingredients.

Benzotiazole‐Based Colorimetric Chemosensor for the Effective Detection of Hazardous Cyanide Ions

AbstractA new hydrazone based on 5‐nitrofurfural and 2‐hydrazinobenzothiazole (L) was introduced as a colorimetric chemosensor for rapid, selective, and sensitive detection of CN− ions in aqueous media. The chemosensor L was characterized using spectral methods such as FT‐IR, 1H, 13C NMR, UV‐Vis, and mass spectrometry. The interaction of L with the CN− ion provides a marked color change from yellow to blue‐green or blue, depending on the concentration of cyanide ions. The change in colour as well as in absorption maxima make it possible to detect CN− ions with the naked eye. The detection limit of the chemosensor L is 0.26 μM, which is below the WHO limit for cyanide ions in drinking water. Other competing anions (F−, Cl−, Br−, I−, SCN−, ClO3−, ClO4−, SO32−, H2PO4−, HSO4−, and NO3−) showed little effect on the detection of cyanide ions. Quantum chemical calculations confirm the recognition mechanism, which is based on the formation of a molecular complex of the −NH‐hydrazine fragment of the chemosensor L with cyanide ion. The chemosensor L applied on the paper and polymeric test strips can be used in experiments to detect cyanide ions in samples of drinking and river water.

A New Chromone‐based Sequential Functioning Colorimetric Chemosensor for Cu2+ and Cysteine in Near‐perfect Aqueous Media

AbstractA selective chromone‐containing colorimetric chemosensor DOCC ((E)‐N,N‐dimethyl‐2‐((4‐oxo‐4H‐chromen‐3‐yl)methylene)hydr azine‐1‐carbothioamide) was designed for the sequential probing of Cu2+ and cysteine. DOCC exhibited a marked color variation from colorless to pale yellow and had the lowest limit of detection (0.30 μM) among the chromone‐based colorimetric sensors for Cu2+ in near‐perfect aqueous media. DOCC could work to probe and quantify Cu2+ in real water samples with great recovery (98‐102%). DOCC could discriminate Cu2+ using the test kit down to 10 μM. On the other hand, Cu2+‐2⋅DOCC could selectively detect cysteine (Cys) in a sequential step through the demetallation reaction. Cu2+‐2⋅DOCC showed that its color returned from pale yellow to colorless only in the presence of Cys and its limit of detection was calculated to be 6.62 μM. The practical applications for Cys were successfully achieved in water samples with perfect recovery (99–100%) and pH tests at 7–9. FT‐IR, Job plot, ESI‐MS, and DFT calculations were applied to explain the sensing mechanisms of Cu2+ by DOCC and Cys by Cu2+‐2⋅DOCC.

Color Stability of Nanoparticles-Modified Dental Resin-Based Composites

To evaluate the effect of beverages (coffee, tea, Cola-Cola, and mineral water) on the color stability of resin-based composite (RBC) materials modified with different nanoparticles (NPs). The specimens (70/beverage) were fabricated from light-cured RBCs and divided according to NPs into four groups: one control, unmodified (N0); and three experimental—ZrO2 (Zr), TiO2 (Ti), and SiO2 (Si) groups. Each experimental group was further subdivided into two subgroups according to NP concentrations: 3 wt.% and 7 wt.% (n = 10). A spectrophotometer was used to assess the color change (∆E) before and after six months of immersion. Data were analyzed and compared using one-way-ANOVA followed by Bonferroni’s post-hoc test (α = 0.05) and subsequently ∆E value conversion to National Bureau of Standards (NBS) units. The modified light-cured RBCs with ZrO2, TiO2, and SiO2 demonstrated smaller color changes after immersion in the beverages than the unmodified group (p &lt; 0.001). Zr groups showed the lowest ΔE, followed by Ti and Si groups; a 3% concentration resulted in a lower mean ΔE than the 7% concentration. NBS findings showed that coffee and tea produced marked unacceptable color changes (NBS units were &gt;3), and Coca-Cola resulted in noticeable color changes (NBS units between 1.5 and 3), while water produced slight color changes (NBS ≤ 1). Modification of RBCs with both concentrations of ZrO2, as well as 3% of TiO2 and SiO2, may improve its color stability. Based on NBS results, RBCs immersed in mineral water and Coca-Cola showed clinically acceptable color changes, while those immersed in coffee and tea were clinically unacceptable.

Synthesis and investigation of bis(phenyl)fluorene and carbazole appended dipodal Schiff base for fluorescence sensing towards Sn(II) ion and its regioselective polymerization

One-pot condensation reaction between 9,9-Bis(4-aminophenyl)fluorene and 9-Ethyl-9H-carbazole-3-carbaldehyde afforded a chemosensor ((N,N′)-4,4′-(9H-fluorene-9,9-diyl)bis(N-((9-ethyl-9H-carbazol-2-yl)methylene)aniline, SB) having Schiff base skeleton. The further step was the synthesis of the polymer (P-SB) via oxidative polycondesation reaction of SB. FT-IR, 1H NMR and 13C NMR instruments were used to characterize the functional groups on the monomer and polymer. Thermal stability and electrochemical features of SB and P-SB were characterized by thermogravimetric analysis-differential thermal analyses (TG-DTA) and cyclic voltammetry (CV), respectively. The glass transition and surface image of P-SB were determined from DSC and SEM measurements, respectively. UV–vis and photoluminescence spectroscopy (PL) allowed to determine the optical properties of SB and P-SB. The obtained polymer, which had the weight average molecular weight of 8400 Da identified by gel permeation chromatography (GPC), exhibited fluorescence property. The synthesized turn-on fluorogenic chemosensor SB showed high selectivity and sensitivity towards Sn2+ among the cations of Ag+, K+, Hg2+, Mn2+, Cd2+, Sn2+, Ca2+, Pb2+, Zn2+, Co2+, Ni2+, Cu2+, Fe3+, Al3+, Cr3+ and Cr6+. The fluorescence turn-on recognition process for the detection of Sn2+ was related to the restriction of CN isomerization, followed by inhibiting intramolecular charge transfer (ICT), with consequent chelation-enhanced fluorescence (CHEF) mechanism. The stoichiometry ratio of the analyte-sensor adduct in the solution was found to be 1:1 by Job's plot method concomitant with a dramatic increase in fluorescent signal at 471 nm and a marked color change from colorless to turquoise blue upon addition of Sn2+ ions. Limit of detection value for the formation of SB-Sn2+ chelation was calculated as 3.37 nM. No change in PL intensity of SB-Sn2+ chelation was observed in the company of other metal ions. Reversibility of the chemosensor in its binding towards Sn2+ was demonstrated in the presence of chelating agent EDTA. The synthesized SB could effectively detect Sn2+ ion as a fluorescent sensor.

Hydrogen-bond induced enhanced emission ratiometric fluorescent handy needle for visualization assay of amoxicillin by smartphone sensing platform.

Amoxicillin (AMO) is one of the most commonly used antibiotics, and its abuse in animal husbandry or clinical therapy can pose unpredictable hazards to humans. Therefore, it is crucial to develop a real-time and rapid method to accurately determine AMO content. Here, we designed a fluorescent nanoprobe for qualitative and quantitative AMO determination by using as-synthesized green safe materials of nontoxic red carbon dots (RCDs) and blue carbon dots (BCDs). In the presence of AMO, a reaction promoting hydrogen bonding occurred immediately, resulting in an instant increase in the intensity of the blue fluorescence of BCDs, accompanied by a marked color change from red to blue. For practical application, we designed a nontoxic sensing fluorescent handy needle to directly and quantitatively detect AMO in real samples. This portable and easy-to-use device was demonstrated on a smartphone platform based on 3D printing technology, which offers the advantages of simple production, excellent visualization, fast response, and instant quantitative detection. The device requires an extremely short detection time and has a sensitive detection limit of 2.39nM. The method presented here enables real-time assessment for food safety, as well as on-site detection under field conditions to track various trace substances for timely health checks.

Effect of Different Denture Cleansers on Color Stability of Acrylic Resin Teeth – An In Vitro Study

Introduction: The durability of denture teeth to colour change is critical in selecting denture teeth, especially in terms of aesthetic demands and patient expectations. It is critical that the artificial teeth color remains constant over time when exposed to various cleaning solutions. The objective of the study is to assess the influence of three different commercially available denture cleansers on the color of acrylic resin teeth using the digital photography method and the Commission Internationale de l’Eclairage (CIE) L*a*b* standard. Methodology: Sixty acrylic maxillary central incisor teeth were divided to three groups of 20 samples each. The samples were left immersed in three different denture cleansers (DENSIVE, SECURE and CLINSODENT) for one month, simulating one month of usage by the patient. Digital photography was used to obtain baseline and final color readouts of the teeth on the basis of CIE L*a*b* standard, using image analysis software (Adobe Photoshop Inc System) and the color alteration (ΔE) of the samples was computed. Results: Maximum color change was found in teeth treated with DENSIVE denture cleanser, followed by CLINSODENT and SECURE, respectively. And this was found to be statistically significant (p-value ≥ 0.05). Conclusion: It is possible to deduce that the color stability of acrylic resin teeth is influenced by the use of denture cleansing solutions, and a marked color change was noted with the digital photography method.

Surface roughness and color changes of dental PEEK related to staining beverages and cleaning methods

Considering that the microstructure, texture and surface characteristics are relevant factors that could affect the appearance and resistance of a material, the study aims to evaluate in vitro, the surface roughness development and color changes related to staining beverages and cleaning methods after simulated periods of clinical use. The discoloration processes of PEEK materials are caused by intrinsic or extrinsic factors and still require elucidation. Three types of unmodified or modified PEEK CAD/CAD materials were selected for investigation: Finoframe, Juvora medical and BioHPP-a reinforced material. Four different staining media were involved: hot coffee, black tea, cold juice, and distilled water as control. For staining thermal cycling was performed between a hot coffee/tea bath (55 °C) and a bath filled with distilled water (37 °C), respective between a cold juice bath (5 °C) and a bath filled with distilled water (37 °C). For cleaning, a chemical method and mechanical brushing were selected. Simulated periods of clinical use were taken into consideration. Roughness measurements (Ra and Rz) were done after each period. Color changes (ΔE*) were calculated based on the CIE L*a*b* color system. Statistical analyses were performed, paired t-Test for comparisons between the means and Spearman correlations to assess relationships between roughness and color changes. After staining beverages, a significant decreased in Ra values for all three materials that were immersed in juice and, for B and F in tea, were measured. Perceivable changes have been identified for J in coffee and for B in tea. After brushing, Ra significant decreased for J, in all immersion environments and no perceivable color changes were reported. The chemical cleaning caused a significant decrease in surface roughness values for B and F, in all immersion environments and color changes were perceivable for J in juice. Surface characteristics were affected by staining, mechanical and chemical cleaning; during the study, no marked color changes of PEEK were detected.

Transcriptomic and metabolomic analyses reveal how girdling promotes leaf color expression in Acer rubrum L

BackgroundAcer rubrum L. (red maple) is a popular tree with attractive colored leaves, strong physiological adaptability, and a high ornamental value. Changes in leaf color can be an adaptive response to changes in environmental factors, and also a stress response to external disturbances. In this study, we evaluated the effect of girdling on the color expression of A. rubrum leaves. We studied the phenotypic characteristics, physiological and biochemical characteristics, and the transcriptomic and metabolomic profiles of leaves on girdled and non-girdled branches of A. rubrum.ResultsPhenotypic studies showed that girdling resulted in earlier formation of red leaves, and a more intense red color in the leaves. Compared with the control branches, the girdled branches produced leaves with significantly different color parameters a*. Physiological and biochemical studies showed that girdling of branches resulted in uneven accumulation of chlorophyll, carotenoids, anthocyanins, and other pigments in leaves above the band. In the transcriptomic and metabolomic analyses, 28,432 unigenes including 1095 up-regulated genes and 708 down-regulated genes were identified, and the differentially expressed genes were mapped to various KEGG (kyoto encyclopedia of genes and genomes) pathways. Six genes encoding key transcription factors related to anthocyanin metabolism were among differentially expressed genes between leaves on girdled and non-girdled branches.ConclusionsGirdling significantly affected the growth and photosynthesis of red maple, and affected the metabolic pathways, biosynthesis of secondary metabolites, and carbon metabolisms in the leaves. This resulted in pigment accumulation in the leaves above the girdling site, leading to marked red color expression in those leaves. A transcriptome analysis revealed six genes encoding anthocyanin-related transcription factors that were up-regulated in the leaves above the girdling site. These transcription factors are known to be involved in the regulation of phenylpropanoid biosynthesis, anthocyanin biosynthesis, and flavonoid biosynthesis. These results suggest that leaf reddening is a complex environmental adaptation strategy to maintain normal metabolism in response to environmental changes. Overall, the results of these comprehensive phenotype, physiological, biochemical, transcriptomic, and metabolomic analyses provide a deeper and more reliable understanding of the coevolution of red maple leaves in response to environmental changes.