Surface Color Change Research Articles

Bio-Inspired Hydrogel-Elastomer Actuator with Bidirectional Bending and Dynamic Structural Color.

In nature, some creatures can change their body shapes and surface colors simultaneously to respond to the external environments, which greatly inspired researchers in the development of color-tunable soft actuators. In this work, we present a facile method to prepare a smart hydrogel actuator that can bend bidirectionally and change color simultaneously, just like an octopus. The actuator is fabricated by elastomer/hydrogel bilayer and the hydrogel layer was decorated with thermoresponsive microgels as the photonic crystal blocks. Compared with the previously reported poly(N-isopropylacrylamide) hydrogel-based bilayer hydrogel actuators, which are generally limited to one-directional deformation, the elastomer/hydrogel bilayer actuator prepared in our work exhibits unique bidirectional bending behavior in accordance with the change of structural color. The bending degrees can be changed from -360° to 270° in response to solution temperatures ranging from 20 °C to 60 °C. At the same time, the surface color changes from red to green, and then to blue, covering the full visible light spectrum. The bending direction and degree of the hydrogel actuator can easily be adjusted by tuning the layer thickness ratio of the elastomer/hydrogel or the composition of the hydrogel. The color-tunable hydrogel-elastomer actuator reported in this work can achieve both programmable deformations and color-changing highly resembling the natural actuating behaviors of creatures.

Comparison of the Surface Properties of 3D-printed Permanent Restorative Resins and Resin-based CAD/CAM Blocks.

This study aimed to investigate the surface roughness, microhardness, and color changes of resin-based computer-aided design/computer-aided manufacturing (CAD/CAM) blocks and 3D-printed permanent resins in different beverages. Resin-based CAD/CAM blocks (Cerasmart 270 and Grandio Blocs) and 3D-printed permanent restorative resins (Crowntec and Permanent Crown) were used in this study. A total of 96 specimens were prepared from CAD/CAM blocks and 3D-printed permanent resins. The initial surface roughness, microhardness, and shade value of the specimens were measured. Then, the specimens prepared from each material were divided into three subgroups (n=8) and immersed in tea, coffee, and distilled water for 30 days. After the specimens were immersed in the beverages, the surface roughness, microhardness, and tone values were measured again. The data were statistically analyzed using a two-way analysis of variance test (p<0.05). No statistically significant difference was found in the surface roughness values of the resin-based CAD/CAM blocks and 3D-printed resins (p<0.05). Resin-based CAD/CAM blocks showed statistically significantly higher microhardness than 3D-printed permanent resins (p<0.05). Although the color changes in 3D-printed resins in tea and coffee were similar to those in resin-based CAD/CAM blocks on the first and seventh days, more color changes appeared in the 3D-printed resins after 30 days. The surface roughness and microhardness values of the specimens submerged in tea, coffee, and distilled water showed no statistically significant changes (p<0.05). Although the surface roughness of 3D-printed permanent resins was similar to that of resin-based CAD/CAM blocks, they had a lower microhardness value. Moreover, 3D-printed permanent resins showed more color changes in tea and coffee.

Metabolomic and microbiomic insights into color changes during the sweating process in Dipsacus asper.

Sweating is one of the most important primary processing methods of Chinese medicinal materials. Dipsacus asper is a typical representative of sweating treatment that is recommended by the Chinese Pharmacopoeia. The color change of the fracture surface of the root is the prominent feature of sweating treatment. However, few studies have focused on the mechanism of color change during sweating treatment. In this study, widely targeted metabolomics and ITS high-throughput sequencing technologies were applied to detect metabolites and microbial structure and diversity in the root of D. asper during sweating treatment. A total of 667 metabolites, including 36 downregulated and 78 upregulated metabolites, were identified in D. asper following sweating treatment. The significantly differential metabolites were divided into 12 classes, including terpenoids and phenolic acids. Moreover, all the differential terpenoids were upregulated and 20 phenolic acids showed a significant change after sweating treatment. In addition, microbial community diversity and richness increased following sweating treatment. The composition of microbial communities revealed that the relative abundances of Ascomycota and Basidiomycota significantly changed after sweating treatment. Correlation analysis revealed that Ascomycota (Fusarium sp., Macrophomina sp., Ilyonectria sp., Memnoniella sp., Penicillium sp., Cyphellophora sp., Neocosmospora sp., unclassified_f_Nectriaceae, and unclassified_o_Saccharomycetales) and Basidiomycota (Armillaria sp.) were associated with the content of terpenoids (6-deoxycatalpol and laciniatoside III) and phenolic acids (3-(4-hydroxyphenyl)-propionic acid, ethyl caffeate, 4-O-glucosyl-4-hydroxybenzoic acid, 2-acetyl-3-hydroxyphenyl-1-O-glucoside, 4-O-glucosyl-3,4-dihydroxybenzyl alcohol, 3-O-feruloylquinic acid, 3,4-O-dicaffeoylquinic acid methyl ester, O-anisic acid, and coniferyl alcohol). We speculate that the Ascomycota and Basidiomycota affect the content of terpenoids and phenolic acids, resulting in color change during sweating treatment in D. asper. This study provides a foundation for analyzing the mechanism involved in the processing of Chinese medicinal materials.

Changes in the properties of bulk-fill resins under conditions of gastroesophageal reflux and bulimia

Aim: Evaluate the roughness, microhardness and color change of different Bulk Fill resins when submitted to the condition of gastroesophageal reflux and bulimia. Methods: 60 specimens (n = 10) of Bulk-Fill composite resins were made: M1 – Filtek™; M2 – Tetric N-Ceram and M3 – OPUS, through a matrix 2x6 mm and light cured by the VALO light source. After polishing, initial analyzes (48 hours - T0) of surface roughness (Ra), microhardness (VHN) and color change (ΔE) were performed. To simulate the oral condition of severe gastroesophageal reflux and bulimia, the specimens were immersed in hydrochloric acid (S1) (pH 1.7) 4 minutes a day, for 7 days. Control group specimens were immersed in artificial saliva (S2). Subsequently to immersions, mechanical brushing was performed for 3 minutes, three times a day, simulating 7 days of brushing. And again, the analyzes of Ra, VHN and ΔE were performed (7 days - T1). Thus, hydrochloric acid immersion, mechanical brushing and Ra analysis were repeated at 14 days (T2) and 21 days (T3); and T2, T3 and T4 (3 years) for VHN and ΔE. Results: After Shapiro-Wilk statistical test, ANOVA and Tukey test with Bonferroni adjustment (p&gt;0.05), M3 showed the lowest Ra at all times compared to the other resins, while the highest Ra was at T0. M1 and T1 showed higher VHN. And M2 and T4 showed higher ΔE. Conclusion: Bulk Fill resins can be indicated for patients with Gastroesophageal Reflux and Bulimia, nonetheless, Tetric N-Ceram resin showed the worst results.

Universal and One-Step Modification to Render Diverse Materials Bioactivation.

Bioactive materials that can support cell adhesion and tissue regeneration are greatly in demand in clinical applications. Surface modification with bioactive molecules is an efficient strategy to convert conventional bioinert materials into bioactive materials. However, there is an urgent need to find a universal and one-step modification strategy to realize the above transformation for bioactivation. In this work, we report a universal and one-step modification strategy to easily modify and render diverse materials bioactivation by dipping materials into the solution of dibutylamine-DOPA-lysine-DOPA (DbaYKY) tripeptide-terminated cell-adhesive molecules, β-peptide polymer, or RGD peptide for only 5 min. This strategy provides materials with a stable surface modification layer and does not cause an undesired surface color change like the widely used polydopamine coating. This one-step strategy can endow material surfaces with cell adhesion properties without concerns on nonspecific conjugation of proteins and macromolecules. This universal and one-step surface bioactivation strategy implies a wide range of applications in implantable biomaterials.

One Step Polishing System Difference on Bulk-Fill Composite Resin Microhardness, Surface Roughness, and Color Stability

Background: The polishing procedure was an important step in composite resin restoration as it reduces restoration surface roughness. Smooth and well-polished restoration surfaces can increase microhardness and minimize discoloration on the tooth surface. The study aims to examine the differences of one-step polishing systems on surface roughness, microhardness, and color stability of bulk-fill composite resin.&#x0D; Method: The samples were bulk-fill composite resin moulded with 4 mm of diameter and thickness (n=30) for microhardness (n=15) and surface roughness (n=15) test and moulded with 6 mm of diameter and 4 mm of thickness for color stability (n=15) test. The samples were divided into three groups consisting of 5 samples for each variable and were polished using PoGo, OptraPol, and OneGloss. Color stability test samples were immersed in tea solution for 7 days. Color stability measurement was done by comparing the results of color measurements using a spectrophotometer before and after immersion. Microhardness was tested using Vickers Microhardness Tester, while surface roughness was tested using the Stylus Profilometer Fowler Surfcorder SE1700.&#x0D; Result: The data analysis showed that PoGo produced the smoothest surface roughness significantly (p=0.006), the highest microhardness significantly (p=0.002), and the lowest color change significantly (p = 0.027)&#x0D; Conclusion: PoGo produced lowest surface roughness and color change, and highest microhardness compare with OptraPol and OneGloss.

Evaluation of the effects of whitening toothpaste containing nanohydroxyapatite on surface roughness and color change in restorative materials.

The effects of whitening toothpastes containing nanohydroxyapatite on the surfaces of restorative materials are not well known. This study evaluated the changes in surface roughness and color of coffee-stained restorative materials after brushing with nanohydroxyapatite and other whitening toothpastes. Disc-shaped specimens were formed using microhybrid, nanohybrid, and supra-nano-filled composite (n = 30) and stained with a coffee solution. A brushing simulation was applied with toothpastes containing nanohydroxyapatite (Dentiste Plus White), perlite (Signal White System) and hydrogen peroxide (Colgate Optic White) for 7, 15, and 30 days. Color and surface roughness measurements were taken before and after brushing. Color change (∆E00) was calculated using the CIEDE2000 system. Supra-nano-filled composite-Dentiste Plus White, supra-nano-filled composite-Colgate Optic White, and nanohybrid composite-Signal White System were the groups with the greatest color change observed on the 7th, 15th, and 30th days, respectively. The smallest color change was seen in the microhybrid composite-Signal White System, microhybrid composite-Dentiste Plus White, and nanohybrid composite-Dentiste Plus White groups on the 7th, 15th, and 30th days, respectively. No significant surface roughness changes were observed in the nanohybrid composite-Dentiste Plus White, supra-nano-filled composite-Colgate Optic White, supra-nano-filled composite-Dentiste Plus White, or supra-nano-filled composite-Signal White System groups. Whitening toothpaste containing nanohydroxyapatite provided a high degree of color change in the short term and did not create significant surface roughness in nanohybrid or supra-nano-filled composites.

Effectiveness of Porcelain Polishing Methods on the Roughness and Color Stability of CAD-CAM Ceramics after Orthodontic Bracket Debonding.

Increased utilization of all ceramic restorations for aesthetic consideration in combination with routine adult orthodontic practice has led to numerous clinical challenges. Obtaining adequate bond strength between the orthodontic bracket and all-ceramic restoration and damage to the ceramic surface during the bracket debonding procedure needs to be better understood. This study analyzed the surface texture and color change of glazed and bracket-debonded ceramic CAD-CAM materials and the efficiency of porcelain polishing systems in restoring surface morphology and color. A total of 30 rectangular test specimens from each lithium disilicate CAD (LD-CAD), polymer-infiltrated ceramic (PICN), zirconia-reinforced lithium silicate glass ceramic (ZLS), and 5YTZP zirconia (5YZP) were prepared. The ceramic samples were embedded within acrylic resin, and baseline surface roughness and color were recorded using an optical profilometer and a reflected color spectrophotometer. The porcelain samples were bonded with lower incisor ceramic brackets. The samples were thermocycled 2000 times between 5 and 55 °C. Afterward, the brackets were peeled with bracket-removing pliers. The resin adhesive from the debonded surface was eliminated with tungsten carbide bur, and samples were randomly divided into three subgroups of (n = 10) to be polished with Diapol-twist (DT), a Keramik-Politur 4313B Komet polishing kit (KK), and a Horico diamond polisher (HDP). The polished surface roughness and color were recorded. The data were statistically analyzed using a two-way analysis of variance at p < 0.05. The debonded porcelain surfaces across the groups displayed significantly higher mean surface roughness (Ra) compared to glazed surfaces. The debonded 5YZP showed the least Ra at 0.661 (0.09), while the highest Ra was recorded by PICN at 4.057 (0.82). All of the polishing systems evaluated in the study significantly reduced the surface roughness. However, they were unsuccessful in regaining the surface topography of the glazed surface. The flexible discs (DT) produced the smoothest surface, followed by the diamond-impregnated rubber points (KK). Unpolished porcelain surfaces had a discernable mean color difference from glazed surfaces. Polished surfaces from the different polishing systems among the all-ceramic groups achieved a clinically acceptable mean color difference. Polishing debonded rough porcelain surfaces is imperative, and flexible discs performed better in all of the tested CAD-CAM ceramic materials.

Effect of silver diamine fluoride/potassium iodide treatment on the prevention of dental erosion in primary teeth: an in vitro study

IntroductionDental erosion has a great effect on oral health, when diagnosed it is irreversible, this sets the importance of different preventive measures being investigated against dental erosion.AimThis in vitro study aims to evaluate the effectiveness of silver diamine fluoride and Potassium iodide (SDF-KI) in comparison to casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) varnish, sodium fluoride (NaF) varnish, silver diamine fluoride (SDF) alone and deionized water as a control group in the prevention of dental erosion in primary teeth and assessing its staining effect.Materials and methodsForty deciduous teeth enamel specimens were randomly allocated into the five study groups. Tested materials were applied. An erosive challenge was done by immersing the specimens in a citric acid-containing soft drink with pH 2.85, for 5 min, 4 times/day, for 5 days. Changes in surface microhardness, mineral loss, and color change were evaluated besides recording of the surface topography and surface roughness for selected specimens.ResultsThe highest decrease in surface microhardness was recorded in the control group (−85.21 ± 10.60%), with a statistically significant difference (p = 0.002). SDF-KI group (−61.49 ± 21.08%) showed no statistically significant difference when compared to CPP-ACPF, NaF, and SDF groups. For calcium and phosphorous loss, control group was statistically significantly higher compared to the treatment groups (p = 0.003) and (p < 0.001) respectively, while there was no statistically significant difference between the tested treatment groups. The highest mean value for color change was recorded in SDF group (26.26 ± 10.31), followed by SDF-KI group (21.22 ± 12.87) with no statistically significant difference between groups.ConclusionsSDF-KI is as effective as CPP-ACPF, NaF varnishes and SDF in the prevention of dental erosion in primary teeth, there was no statistically significant difference regarding its staining potential.

Repeated Etching Cycles of Resin Infiltration up to Nine Cycles on Demineralized Enamel: Surface Roughness and Esthetic Outcomes-In Vitro Study.

Resin infiltration (RI) is used to mask enamel opacities. There are three recommended etching cycles. However, anecdotal evidence suggests that favorable esthetics outcomes can be obtained by increasing the etching cycles. This study aimed to evaluate the effects of repeated etching cycles during RI application on esthetic changes and surface roughness of demineralized enamel at multiple treatment stages. Artificial demineralization was prepared on the buccal surface of ninety sound extracted premolars. The teeth were divided into nine groups (n = 10); with each consecutive group having one additional etching cycle up to nine etching cycles. Resin infiltrant was performed twice, first for 3 min (Resin 1) and again for 1 min (Resin 2). Surface roughness and esthetic changes were assessed using a profilometer (Ambios XP-200) and Minolta spectrophotometer, respectively, at baseline (sound enamel), etching, resin 1, resin 2, 7 days, and 28 days post resin applications. Data were analyzed with two-way ANOVA (p < 0.05). There was a significant interaction between the different stages and various groups of etching cycles on surface roughness, F(48, 126) = 3.48, p < 0.001. There was a significant interaction between the different stages and various groups of etching cycles on color changes, F(4, 126) = 1.177, p = 0.045. The surface roughness of demineralized enamel infiltrated with RI was less than that of sound enamel (baseline). There is a significant difference in color changes between resin 1 and resin 2 (p < 0.05). After five etching cycles, RI improved the esthetic of the color of teeth similar to the baseline. Surface roughness and color changes remained constant for 28 days. RI can be considered an effective and predictable treatment option for the restoration of early enamel lesions owing to its better surface characteristics and reliable masking effects. The color stability and surface roughness stay unaltered for up to 28 days.

Detection of artificial enamel caries-like lesions with a blue hydroxyapatite-binding porosity probe

ObjectivesThis in vitro study investigated the ability of a blue protein-based hydroxyapatite porosity probe to selectively detect artificial enamel caries-like lesions of varying severities. MethodsArtificial caries-like lesions were formed in enamel specimens using a hydroxyethylcellulose-containing lactic acid gel for 4/12/24/72 or 168 h. One untreated group was used as a control. The probe was applied for 2 min and unbound probe rinsed off with deionized water. Surface color changes were determined spectrophotometrically (L*a*b* color space) and with digital photography. Lesions were characterized using quantitative light-induced fluorescence (QLF), Vickers surface microhardness, and transverse microradiography (TMR). Data were analyzed using one-way ANOVA. ResultsDigital photography did not reveal any discoloration in unaffected enamel. However, all lesions stained blue with color intensity positively correlated with demineralization times. The color data reflected similar trends: lesions became significantly darker (L* decreased) and bluer (b* decreased), while overall color differences (ΔE) increased significantly after probe application (4-h lesion, mean±standard deviation: ΔL*=-2.6 ± 4.1/Δb*=0.1 ± 0.8/ΔE=5.5 ± 1.3 vs. 168-h lesion: ΔL*=-17.3 ± 1.1/Δb*=-6.0 ± 0.6/ΔE=18.7 ± 1.1). TMR analysis revealed distinct differences in integrated mineral loss (ΔZ) and lesion depth (L) between demineralization times (4-h lesion: ΔZ=391±190 vol%min × µm/L = 18.1 ± 10.9 µm vs. 168-h lesion: ΔZ=3606±499 vol%min × µm/L = 111.9 ± 13.9 µm). QLF and microhardness were also able to differentiate between demineralization times. L and ΔZ strongly correlated (Pearson correlation coefficient [r]) with Δb* (L vs. Δb*: r=-0.90/ΔZ vs. Δb*: r=-0.90), ΔE (r = 0.85/r = 0.81), and ΔL* (r=-0.79/r=-0.73). ConclusionConsidering the limitations of this study, the blue protein-based hydroxyapatite-binding porosity probe appears to be sufficiently sensitive to distinguish between unaffected enamel and artificial caries-like lesions. Clinical significanceEarly detection of enamel caries lesions remains one of the most critical aspects in the diagnosis and management of dental caries. This study highlighted the potential of a novel porosity probe in detecting artificial caries-like demineralization by objective means.

Modified Lignin Nanoparticles as Potential Conservation Materials for Waterlogged Archaeological Wood

Lignin is the most abundant component in archaeological waterlogged wood, making it a potential consolidant with high compatibility for historical wood conservation. However, its consolidation effect is limited by its low penetration into the wood. In this study, modified lignin nanoparticles (LNPs) were proposed for the first time as conservation materials for waterlogged archaeological wood. Two modified LNPs were prepared with low molecular weight, small size, and high solubility in ethylene glycol (EG) for consolidating waterlogged wood samples. These nanoparticles, hydrophilic aminated LNPs (ALNPs) and hydrophobic esterified LNPs (MALNPs), greatly improved the consolidation effect of waterlogged wood samples compared to LNPs. This was demonstrated by measuring their physical properties, dimensional stability, and mechanical properties. The surface color change was almost within the acceptable range for the human eye. We also discussed two different reinforcement mechanisms of ALNPs and MALNPs. ALNPs can form hydrogen bonds with hemicellulose/cellulose in the wood to strengthen the fragile wood cell wall, while MALNPs can fill the wood cell lumen to support the cell wall and prevent deformation during drying. Our work provides an approach of using biomaterials as consolidants for archaeological waterlogged wood and expands the use of lignin in this field.

Surface protection of wood using cerium oxide nanoparticles dispersed paraffin wax nanoemulsion

Exposure to solar UV radiation and other environmental factors promotes the degradation and reduces the serviceability of the wood material under outdoor use. Oils and waxes have been found to be promising solutions for wood protection. This study elucidates the use of paraffin wax based emulsions incorporated with cerium oxide nanoparticles to improve weathering performance of wood. For this purpose, paraffin wax nanoemulsions were prepared by ultrasonication method using tween 80 as surfactant. Cerium oxide nanoparticles (conc. 0.5- to 2%) were added to provide protection against degradation caused by solar UV radiation. The storage stability of nano emulsion was assessed over a period of 30 days by measuring effective particle size and zeta potential. The microstructure of nanoemulsions was observed by optical microscopy and distribution of CeO2 nanoparticles on coated wood was observed through scanning electron microscopy (SEM). The chemical changes were analyzed by Fourier Transform Infrared spectroscopy (FTIR). Wood specimens of Pinus radiata coated with nanoemulsions were subjected to the accelerated weathering tests for 500h. The time dependent changes in surface color of uncoated and coated wood samples were examined. Moreover, the chemical changes on exposed wood surfaces were analyzed by ATR-FTIR spectroscopy. Stable and homogenous nanoemulsions with particle diameter between 200 and 400 nm were formed and exhibited excellent storage stability. Results of color changes showed that maximum degradation was observed in uncoated wood whereas wood coated with paraffin wax nanoemulsion alone could not improve the UV resistance. However, the addition of cerium oxide nanoparticles proved to be efficient in controlling the color changes on wood surfaces. The degradation of wood components reduced significantly in cerium oxide coated wood which was confirmed by FTIR results.

Study of the Interference Color with Nomarski Prism Wedge Angle in a Differential Interference Contrast Microscopy System

Differential interference contrast microscopy systems demonstrate the phase (optical path) rather than the amplitude of a sample. Previous studies have usually approximated the optical path difference produced by the Normarski prism. We derive the mathematical expression for the optical path difference produced by the incident light at any position of the Nomarski prism. As a result, the optical path difference introduced by the differential interference contrast microscope can be calculated. Moreover, the optical path difference is linearly related to the position of the incident light. In addition, the differential interference contrast microscopy system uses a composite light source, while previous studies were basically performed at a single wavelength. The standard wavelengths d (656 nm), F (587 nm), and C (486 nm) are taken as examples to analyze the relationship between the interference color change of the observation surface under the superposition of different wavelengths and the prism wedge angle when the prism moves. When the prism moves the same distance, the larger the prism wedge Angle is, the faster the interference color change is. The analysis based on practical considerations in this paper is believed to provide a method for studying Nomarski prisms.

Impact of elevated temperatures on the mechanical properties and microstructure of waste rubber powder modified polypropylene fiber reinforced concrete

To investigate the impact of elevated temperature on the residual mechanical properties and microstructure of waste rubber powder modified polypropylene fiber concrete (RPFC). A total of 20 mix proportions were designed, considering the effects of waste rubber powder (WPR) dosage, polypropylene fiber (PP fiber) dosage and different ambient temperatures on the mechanical properties and microstructure of RPFC. Surface color change, weight loss, residual compressive strength of RPFC were evaluated after exposure to 100C, 200C, 400C and 600C. Meanwhile, the digital image correlation (DIC) technique was adopted to monitor the surface crack development of prism specimens at different loading stages. By X-ray diffraction (X-RD) analysis and scanning electron microscope (SEM) observation, the chemical and physical changes of RPFC were explored comprehensively. The results showed that the weight loss of RPFC increased after high temperature and the microcracks on the surface of the specimen increased significantly with the WRP content increase at 600 °C. Below 200 °C, the strength loss rate of RPFC is lower than that of PP fiber concrete; it is significantly higher in 400C than that of PP fiber concrete. RPFC exhibits lower intensity in the X-RD curve than that of PP fiber concrete. The needle-like channels and pores formed thanks to fibers and WRP melting helps to release the vapor pressure and improve the concrete resistance to bursting. Finally, the relationship between ambient temperature and compressive strength was established.

Prediction of the color change of surface thermally treated wood by artificial neural network

Prediction of the color change of surface thermally treated wood by artificial neural network

Cellulose Nanocrystals Chiral Nematic Coating with Reversible Multiple-Stimuli-Responsive Coloration

Due to their unique chiral nematic structure and special optical property, cellulose nanocrystals (CNCs) have drawn enormous attention. However, the inherent brittleness and rigidity limit their application in coatings or free-standing films. In this work, we designed and fabricated a novel iridescent coating with multiple-stimuli-responsive coloration through photochemical cross-linking with CNCs, poly(ethylene glycol) diacrylate (PEGDA), and erythritol. The as-prepared coatings exhibited improved mechanical strength because of the introduction of covalent organic frameworks and the internal hydrogen-bonding interaction of CNCs, cross-linked PEGDA networks, and erythritol that provided efficient energy dissipation. Interestingly, the CNC coating was able to distinguish similar organic liquids, including the skeletal isomers (1-propanol/2-propanol), halogenated hydrocarbons (chloroform/dichloromethane), and homologous compounds (methanol/ethanol), quickly by the change in surface color when immersed in various organic solvents. In addition, the CNC coating exhibited reversible humidity sensitivity with wide color changes from cyan to yellow-green, salmon pink, red, and colorless under 30–98% air relative humidity (RH). Based on the reversible discoloration of CNC coating, the anti-counterfeiting performance on CNC coating was presented, and the handwriting of saline solution appeared reversibly when stimulated with ethanol. Thus, the reversible allochroic CNC-based coating platform with multiple-stimuli-responsiveness has the potential to be developed as solvent sensors, test papers, and encryption tools.

Temporary solidification and extraction of marine archaeological wood underwater at a depth of seven meters: A further contribution

In-situ solidifying extraction of large-volume and severely damaged underwater fragile artifacts is still one of the major issues in underwater archaeology. Recent evidence suggests that veratraldehyde can be used to temporarily solidify artifacts underwater; however, it is still challenging to use it in actual archaeological sites. This prospective study was conducted in a seven-meter-deep pool wherein veratraldehyde was used to solidify and extract waterlogged ship wood from the “Nanhai I” shipwreck. The entire underwater extraction process was recorded using a camera. The change in the wood surface color before and after extraction was relatively minor. Scanning electron microscopy analysis revealed that the wood microstructure was not significantly damaged, while nuclear magnetic resonance analysis showed no residues of veratraldehyde and its oxidation products. Overall, the proposed method utilizes a set of scientific techniques for successful in-situ solidifying extraction of underwater fragile wooden artifacts.

Color-encoded Escherichia coli assay via enzyme-induced etching of Au@MnO2 nanoparticles

Au@MnO2 nanoparticles (NPs), as core–shell nanostructures, have been widely used in ions, molecules and enzyme activities detection due to their stable properties and easy preparation, but their application in bacterial pathogens detection is rarely reported. In this work, Au@MnO2 NPs is employed for Escherichia coli (E. coli) detection through monitoring and measuring β-galactosidase (β-gal) activity based enzyme-induced color-code single particle enumeration (SPE) method. In the existence of E. coli, p-aminophenylβ-D-galactopyranoside (PAPG) can be hydrolyzed to generate p-aminophenol (AP) by the endogenous β-gal of E. coli. MnO2 shell reacts with AP and produces Mn2+, causing the blue shift of the localized surface plasmon resonance (LSPR) peak and color change of the probe from bright yellow to green. With the SPE method, the amount of E. coli can be quantified readily. The detection limit reaches 15 CFU/mL with dynamic range from 100 to 2900 CFU/mL. Besides, this assay is effectively employed to monitor E. coli in river water sample. The designed sensing strategy provides an ultrasensitive and low cost way for E. coli detection and has the possibility to detect other bacteria in environmental monitoring and food quality analysis.

Considering Covid-19 Treatments as Applied to Facility Seating: Developing a Methodology to Examine Adverse Surface Color Effects

During Covid-19, a facility management researcher/instructor team examined potential effects of various disinfectant treatments on the surface appearance of furniture currently located in their academic facility. Treatments (i.e., bleach wipes, alcohol wipes, disinfectant sprays and UltraViolet wands) are used by students, staff, faculty, visitors, facility managers and custodians in an effort to reduce spread of Corona. Further, EMist© with Vital Oxide treatments were regularly applied by University-contracted facility maintenance staff during study period. While procedures exist for measuring color change regarding light exposure and changes due to abrasion, no current published methods were found regarding surface color before and after Covid-19 intervention treatments. Researchers/instructors anticipate findings from study would inform facility management and other courses. They anticipate results would allow generalizability to hospitality and healthcare. Changes in surface color of upholstered furniture in facilities may be extremely negative regarding interior aesthetics, corporate image, and replacement costs. Therefore, it was determined there was a great need to study the effects of treatments and inform facility stakeholders. Researchers posited that Covid-19 intervention treatments may alter surface color of upholstered furniture over time. The purpose of the study was to develop methodology to examine color degradation that may be caused by agents used in common disinfecting practices. Three seating pieces (drafting chair, drafting stool, classroom chair) made of different materials were studied. Five treatments were applied to each furniture piece at regular intervals over an 8-week period. Researchers measured color before and after treatments. The procedures were photo-documented and videotaped to capture treatments in-process and to support future educational presentations. Preliminary findings revealed limited variability in color changes. Future research should consider other seating and room-finish materials, disinfectants and treatments, facility types, and timeframes.