Substrate Color Research Articles

Identifying the proximal cue(s) for pupal color variation in the bordered patch butterfly, Chlosyne lacinia (Lepidoptera: Nymphalidae)

Abstract Coloration is a multifaceted trait that serves various functions, including predator defense, thermoregulation, and immune response, among others. We investigated pupal color variation in Chlosyne lacinia pupae, focusing on identifying the cue that influences variation in melanization. Through laboratory experiments, we demonstrated that pupae reared on black backgrounds exhibited significantly higher melanization compared to those on white backgrounds. Additionally, black pupae experienced longer developmental periods, suggesting a trade-off between defense and developmental time. Our findings support crypsis as a likely evolutionary driver for increased melanization in response to substrate color. We discuss potential implications for predator avoidance, immune response, and developmental costs associated with melanization. This study provides insights into the adaptive significance of pupal melanization in response to environmental cues, shedding light on the complex interplay between life history traits in butterflies.

Visual Interpretation of High-Resolution Aerial Imagery: A Tool for Land Managers

Abstract Remotely sensed imagery from various collection platforms (e.g., satellites, crewed and uncrewed aircraft) are used by biologists and other conservation personnel to support management activities ranging from monitoring invasive species to assessing land cover and vegetation characteristics. Although remote sensing–based vegetation indices and models have been developed and used for some management applications, straightforward visual interpretation of imagery by on-the-ground personnel may be a pragmatic approach for obtaining time-sensitive and spatially relevant information to support and guide local management activities. Our primary objective was to qualitatively assess our ability to identify patches of target invasive plant species based on simple visual interpretation of high-resolution aerial imagery. We also sought to compare the high-resolution imagery to widely available imagery (e.g., National Agriculture Imagery Program) to determine the efficacy of each for assessing vegetation communities and land-cover features in support of management activities. To accomplish these objectives, we obtained high-resolution imagery and visually scanned and assessed the imagery by using standard geographic information system software. We were able to differentiate patches of crownvetch Securigera varia (L.) Lassen and wild parsnip Pastinaca sativa L., but not spotted knapweed Centaurea stoebe L. or leafy spurge Euphorbia esula L. The relative success in identifying these species had a relationship to plant characteristics (e.g., flower color and morphology, height), time of year (phenology), patch size and density, and potentially site characteristics such density of the underlying vegetation (e.g., grasses), substrate color characteristics (i.e., color contrast with flowers), and physical disturbance. Our straightforward, qualitative assessment suggests that visual interpretation of high-resolution imagery, but not some lower-resolution imagery, may be an efficient and effective tool for supporting local invasive species management through activities such as monitoring known patches, identifying undetected infestations, assessing management actions, guiding field work, or prioritizing on-the-ground monitoring activities.

Restoration of fractured anterior tooth with monochrome composite resin in pediatric dental patient

Direct restoration with monochromatic composite resin is a treatment option for teeth with coronal fracture after dentoalveolar trauma. This restorative material, in principle, is capable of mimicking the color of the dental substrate. This study aimed to report and discuss the technique of direct restoration with monochromatic composite resin, in a child patient. An 8-year-old male patient attended the Emergency Room of the Baby Clinic of the State University of Londrina for immediate treatment after dentoalveolar trauma that resulted in enamel and dentin fracture, without pulp involvement. As a procedure, restoration was performed with glass ionomer cement and referral to the institution's Dental Residency program. In this service, after case planning, the restoration of the coronal fracture of the substrates was performed with the insertion of multiple increments of the Vittra APS Unique (FGM) composite, with the aid of a silicone guide prepared based on a waxing model to facilitate the reestablishment of the palatal surface form and anatomy. In the clinical follow-up evaluation, the aesthetic and functional results obtained were considered highly satisfactory by patients, relatives and dental clinicians. Thus, it can be concluded that the option for monochromatic composite resin is a viable alternative to make it easier for the dental clinicians to perform the procedure and reduce the clinical time, a relevant fact because it is a case of caring for a pediatric dentistry patient.

Masking ability of gingiva-colored resin-based composites over different tooth-colored substrates.

The purpose of the study was to investigate the influence of different tooth-colored substrates and restoration thicknesses on the final color of gingiva-colored resin-based composites (GCRBCs). Five different shades of GCRBCs [light pink (LP), dark pink (DP), orange (Or), brown (Br), and purple (P)] were used to prepare disc-shaped specimens with 2 different thicknesses: 1.0mm, and 2.0mm. GCRBC discs (n = 5) were placed over 3 different tooth-colored substrates (ND1, ND5, and ND9) and color parameters were assessed using a spectroradiometer. Color differences (∆E*ab and ∆E00) were calculated using CIELab and CIEDE2000 formulas and compared to 50:50% perceptibility (PT: ∆E*ab = 1.7, ΔE00 = 1.1) and acceptability (AT: ∆E*ab = 3.7, ΔE00 = 2.8) visual thresholds. Color variation data were statistically analyzed using two-way ANOVAs followed by Bonferroni's post hoc tests (a = 05). The ∆E*ab and ΔE00 values of GCRBCs placed over ND9 substrates were significantly higher in the LP-1.0mm and Or-1.0mm groups that presented values above AT (p< .001).Regardless of the substrate color and GCRBC thickness applied, ∆E*ab and ΔE00 values below AT were recorded in the gingival color groups of P. Substrate color significantly affected the color differences in the gingival color groups of LP, DP, and Or with a restoration thickness of 1.0mm (p < .05). Gingival color, restoration thickness, and substrate color influenced the color differences of GCRBCs. When the gingival color was a lighter gingival color, rather than dark purple, the masking ability was decreased, especially with a restoration thickness of 1.0mm.

The influence of the textile substrate color on the contrast of thermochromic prints

Thermochromic inks have attracted much attention due to their application in various fields, including the textile industry. The application of these colors in sports clothing enables the monitoring of the athlete’s physiological state through the possibility of changing the color of the material under the influence of skin temperature. Due to the printing of thermochromic inks on textile materials used for visual control, there is a need to analyze the contrast of the printed elements. Contrast plays a significant role in visually highlighting shapes and details and also facilitates the recognition of printed parts and information on textile materials. Contrast analysis of thermochromic inks on different colors of textile materials plays a role in determining the optimal combination of base colors and thermochromic inks that will result in the most noticeable color change. This analysis allows designers and manufacturers to make good decisions about choosing the colors of textile materials when printing with thermochromic inks because, in this way, a high level of aesthetics and functionality is achieved. This work aims to compare and analyze the contrast of thermochromic inks on different colors of the substrate of different types of materials, as well as to determine whether the color of the fabric on which the thermochromic ink is printed affects the color contrast when it is changed, i.e., its discoloration and return to its original state. Magenta reversible thermochromic water-based leuco dye was used to print the samples. The work used textile materials for printing with different structures and different colors. The colors were chosen to be bright and to provide a good contrast with the magenta color so that their combination attracts the viewer’s attention and can create a strong visual effect. Colorimetric and contrast analyses determined that the color of the substrate is dependent on the contrast value. In the case of polyester textile material, the white color of the substrate showed the highest contrast values. On the other hand, in the case of printed samples on a material made of a mixture of polyester and elastane, it can be concluded that the gray color of the substrate gives the highest contrast values. In conclusion, the research highlights the importance of choosing colors and materials to achieve optimal results in the design and production of textile materials with thermochromic inks.

Robust and Durable Photonic Crystal with Liquid-Repellent Property for Self-Cleaning Coatings and Structural Colored Textiles.

Photonic crystal coatings with unique structural colors and self-cleaning properties have been providing an efficient way for substrate coloration. However, the enhancement of the robustness and durability of structural colored coatings to meet the requirements in diverse environments remains a challenging task. Here, to realize the application of photonic crystal films under various kinds of conditions, we present a poly(fluoroalkyl acrylate)-based colloidal photonic crystal (fCPC) coating. Fluorinated core-interlayer-shell (FCIS) colloidal particles of polystyrene (PS) core, poly(methyl methacrylate) (PMMA) interlayer, and poly(fluoroalkyl acrylate-ethyl acrylate-butyl acrylate) (P(FA-EA-BA)) shell copolymers have been first prepared by a stepwise emulsion polymerization. fCPCs with self-supporting property, reprocessing ability, friction resistance, as well as excellent wettability and liquid-repellent properties are successfully obtained via the bending-induced ordering technique (BIOT). When applied in antifouling applications, the fCPC film exhibits resistance against various oil and inorganic liquids. Furthermore, the fCPC coatings demonstrate their durability under outdoor conditions by maintaining stable color appearances during rainy and sunny conditions. Additionally, an electronic product adhered with the fCPC coatings is presented, which exhibits a surface that remains clean even after prolonged usage in comparison to the conventional CPC coating. Structural colored textiles with enhanced stability and functionalized liquid-repellent properties are achieved through a one-step process using FCIS particles. Therefore, the developed self-cleaning and comprehensive fCPC coatings capable of withstanding diverse conditions may open up new avenues for the advancement of structural coloration in decoration, vehicle, textile, and building.

Quantitative examination of factors influencing the colour reproduction ability of lithium disilicate glass-ceramics

BackgroundEffects of ceramic translucency, layer thickness, and substrate colour on the shade of lithium disilicate glass-ceramic restorations proved to be significant in several studies, however, quantitative, numerical results on the relationship between the colour difference and these parameters are still lacking. The purpose of this in vitro study was to quantitatively determine how the colour reproduction ability of a lithium disilicate glass-ceramic is affected by its translucency, layer thickness, and substrate colour.MethodsCeramic samples were prepared from A2 shade IPS e.max CAD blocks with high and low translucencies (HT and LT) in a thickness range of 0.5–2.5 mm (+/- 0.05 mm). Layered samples were acquired utilizing composite substrates in 9 shades; transparent try-in paste was used. The spectral reflectance of the specimens was assessed under D65 standard illumination with a Konica Minolta CM-3720d spectrophotometer. The CIEDE2000 colour difference (ΔE00) between two samples was analysed using perceptibility and acceptability thresholds set at 50:50%. Statistical analysis involved linear regression analysis and the Kruskal–Wallis test.ResultsAn increase in the thickness of 0.5 mm reduced the ΔE00 of the HT samples to 72.8%, and that of the T samples to 71.1% (p < 0.0001). 7 substrates with HT and LT specimens had significantly different results from the mean (p < 0.05). A thickness of 0.5 mm is not sufficient to achieve an acceptable result at any level of translucency, while the low translucency ceramic at a thickness of 1.5 mm gave acceptable results, except for severely discoloured substrates (ND8 and ND9).ConclusionsThe colour reproduction ability of lithium disilicate glass-ceramics is significantly affected by their translucency, layer thickness, and 7 substrates out of 9 substrates examined.

Generation of Wide Color Gamut in a Collisional and Magnetized Plasma by Laser‐Induced Coloration on Composite Structure Surfaces

AbstractIn this paper, a new scheme for generating a wide gamut of structural colors on the thin‐film‐stack‐based (TFSB) substrates is proposed. The TFSB surfaces consist of titanium/random gold nanoparticles (AuNPs) and titanium/ random gold and copper nanoparticles (Au+CuNPs), which can trigger more resonance absorption and widen the color gamut. The electric fields in two designed structures are simulated, and the results showed that the random distribution of AuNPs and Au+CuNPs enhance the uniform local surface plasmon resonance (LSPR) response. This enhancement is crucial in broadening the coverage of the reflection spectrum, which enables the generation of a wide range of colors, including green and red. The influence of laser parameters on the color of TFSB substrates and tested their durability in terms of time is analyzed. Finally, a color palette and made structural color patterns on TFSB by nanosecond pulsed laser are prepared. The proposed new scheme can be easily fabricated by magnetron sputtering without requiring additional procedures, which can open new perspectives in plasmonic colors. This work demonstrates that the promising potential of methods in creating a wide color gamut on metallic surfaces. Additionally, it serves as a means to store information for the preservation and protection of traditional cultures.

Iron-copper nanozyme mimicking laccase for colorimetric determination of deoxynivalenol in feed

Due to the simplicity of their synthesis, robust stability, and adjustable enzymatic activities, nanozymes are particularly effective in inducing changes in substrate coloration, thus proving to be invaluable tools in colorimetric analysis. In this study, terephthalic acid was employed as an organic ligand to synthesize an iron-copper nanozyme with laccase activity using a one-pot hydrothermal method. Remarkably, the introduction of deoxynivalenol (DON) enhanced the laccase activity, significantly deepening the substrate’s color. The absorbance displayed a strong correlation with DON concentrations ranging from 5 μM to 35 μM, following the linear equation Y = 0.03097x + 0.00883 with a correlation coefficient (R2) of 0.994, and the limit of detection (LOD) was found to be 0.59 μM. This developed colorimetric method was then applied to determination DON in wheat, wheat bran, and corn samples, exhibiting relative standard deviations (RSD) between 1.5 % and 2.8 %. The analytical results were consistent with those obtained using the standard high performance liquid chromatography (HPLC) method. Therefore, this rapid, sensitive, and cost-effective technique promises efficient determination of DON in feed samples.

Influence of Fe2O3 on the absorptivity of in situ synthesized solar high-temperature absorbing and storing integrated mullite-based ceramics

Solar energy absorption and storage of integrated ceramic materials is both the absorption of sunlight and storage of sunlight into thermal energy functional materials. In this paper, the effect of Fe2O3 on the solar absorptivity, thermal storage properties, sintering temperature, and physical properties of mullite-based thermal storage ceramics was investigated. The results show that the absorptivity and thermal storage density of the sample AF4 (Bauxite:50 wt%, Clay:50 wt%, Fe2O3:11 wt%) after sintering at 1420 °C are 87.2% and 1116.5 kJ kg−1, respectively; and the unit volume of the AF4 sample can provide the power grid with 918.01 kW h of electricity, save 112.91 kg of coal, and reduce 361.33 kg of CO2 emission. This study systematically elucidated the mechanism of the enhancement of sample absorption caused by Fe3+ doping-induced changes in substrate color, reduction in material forbidden bandwidth, and lattice anharmonic vibration effect, in addition to comprehensively evaluating the feasibility of the optimal AF4 sample for use in solar energy absorbing and storing integrated ceramic materials.

Iridescent transparent passive radiative cooling enabled by cellulose nanocrystal assemblies

Recently, passive daytime radiative cooling (PDRC) materials that reflect sunlight and transmit heat through atmospheric transparent windows to outer space without any energy consumption have attracted broad interest. However, most PDRC materials have the complicated structures, white or mirror-like appearance with poor transparency. Here, we reported a transparent iridescent PDRC coating material constructed by the evaporation-induced self-assembly (EISA) of cellulose nanocrystals (CNCs). The iridescent PDRC coating not only shows high light transparency (75 %) because the right-handed circularly polarized light can transmit the unique left-handed chiral nematic liquid crystal structure, but also shows high solar reflection efficiency (95.2 %) and infrared emission efficiency (96.5 %) that endows the coating with high radiative cooling efficiency (119 W/m2). More importantly, the PDRC coating can apply on polymethyl methacrylate (PMMA), polyethylene terephthalate (PET) film and textiles, and the substrate color has no negative impact for cooling. With the excellent radiative cooling efficiency, high transparency, facile preparation process and general applicability, the CNCs-based PDRC coating opens a new pathway toward the potential application of PDRC for environmental sustainability purpose.

Variable effects of substrate colour and microtexture on sessile marine taxa in Australian estuaries

Concrete infrastructure in coastal waters is increasing. While adding complex habitat and manipulating concrete mixtures to enhance biodiversity have been studied, field investigations of sub-millimetre-scale complexity and substrate colour are lacking. Here, the interacting effects of ‘colour’ (white, grey, black) and ‘microtexture’ (smooth, 0.5 mm texture) on colonisation were assessed at three sites in Australia. In Townsville, no effects of colour or microtexture were observed. In Sydney, spirorbid polychaetes occupied more space on smooth than textured tiles, but there was no effect of microtexture on serpulid polychaetes, bryozoans and algae. In Melbourne, barnacles were more abundant on black than white tiles, while serpulid polychaetes showed opposite patterns and ascidians did not vary with treatments. These results suggest that microtexture and colour can facilitate colonisation of some taxa. The context-dependency of the results shows that inclusion of these factors into marine infrastructure designs needs to be carefully considered.

Evaluation of the Color of Zirconia in Different Substrates of Osseointegrated Implants, Thickness of Materials and Types of Resin Cements.

Objectives: To evaluate the impact of surface conditioning of titanium, zirconia thickness, and cement type on the final color of zirconia luted to the titanium. Methods: A total of 192 grade 5 titanium specimens with the final dimensions 10 mm × 10 mm × 2 mm were fabricated and subjected to four different surface conditioning including, that is, sandblasting, etching, and anodization. In addition, 192 zirconia specimens with the same dimensions as the titanium specimens but altered thicknesses of 0.7 (n = 96) and 1.0 (n = 96) mm were fabricated using 5Y-TZP zirconia. Color as expressed by L ∗ (lightness), a ∗ (red-green axis), and b ∗ (blue-yellow axis) of titanium and zirconia specimens as well as the joined titanium-zirconia complex, total assembly (Panavia V5 clear, PC; opaque, PO, each n = 96) were determined under standardized conditions using a spectroradiometer (SpectraScan P-650). Color differences were calculated using the ΔE 00 formula. ANOVA supplemented with post hoc Tukey test for group comparisons was compiled to estimate possible effects of titanium conditioning, zirconia thickness, and type of cement used on the final zirconia color (SPSS Ver. 28; α = 0.05). Results: All investigated factors affected the zirconia color of the total assembly (p < 0.001). Using PO mean values of all groups were still close to baseline colors (ΔE 00 between 5.5 and 6.2). When using PC, the final color was significantly altered, irrespective of the other parameters. Specimens luted with PO appeared lighter, less reddish (a ∗ was affected predominately by sample thickness), and more bluish, while luting with PC resulted in reduced lightness combined with large shifts along the red and yellow axes. Significance: Color changes of zirconia luted to titanium are primarily affected by the color of the substrate if a translucent cement was used. Vice versa, the application of an opaque cement effectively masked the dark substrate color. Substrate color and choice of cement have to be taken into consideration when performing shade selection.

Color discrepancy of single-shade composites at different distances from the interface measured using cell phone images.

This study aimed to evaluate the impact of substrate color and interface distance on the color adjustment of 2 single-shade composites, Vittra APS Unique and Charisma Diamond One. Dual disc-shaped specimens were created using Vittra APS Unique or Charisma Diamond One as the center composite, surrounded by shaded composites (A1 or A3). Color measurements were taken with a spectrophotometer against a gray background, recording the color coordinates in the CIELAB color space. Illumination with a light-correcting device and image acquisition using a polarizing filter-equipped cell phone were performed on specimens over the same background. Image processing software was used to measure the color coordinates in the center and periphery of the inner composite and in the outer composite. The color data were then converted to CIELAB coordinates and adjusted using data from the spectrophotometer. Color differences (ΔE00) between the center/periphery of single-shade and outer composites were calculated, along with color changes in single-shade composites caused by different outer composites. Color differences for the inner composites surrounded by A1 and A3 were also calculated. Data were analyzed using repeated-measures analysis of variance (α = 0.05). The results showed that color discrepancies were lowest near the interface and when the outer composite was whiter (A1). Additionally, Charisma Diamond One exhibited better color adjustment ability than Vittra APS Unique. Color discrepancies between the investigated single-shade composites diminished towards the interface with the surrounding composite, particularly when the latter exhibited a lighter shade.

Application of the Peroxidase‒like Activity of Nanomaterials for the Detection of Pathogenic Bacteria and Viruses.

Infectious diseases caused by pathogenic bacteria and viruses pose a significant threat to human life and well-being. The prompt identification of these pathogens, characterized by speed, accuracy, and efficiency, not only aids in the timely screening of infected individuals and the prevention of further transmission, but also facilitates the precise diagnosis and treatment of patients. Direct smear microscopy, microbial culture, nucleic acid-based polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA) based on microbial surface antigens or human serum antibodies, have made substantial contributions to the prevention and management of infectious diseases. Due to its shorter processing time, simple equipment requirements, and no need for professional and technical personnel, ELISA has inherent advantages over other methods for detecting pathogenic bacteria and viruses. Horseradish peroxidase mediated catalysis of substrate coloration is the key for the detection of target substances in ELISA. However, the variability, high cost, and environmental susceptibility of natural peroxidase greatly limit the application of ELISA in pathogen detection. Compared with natural enzymes, nanomaterials with enzyme-mimicking activity are inexpensive, highly environmentally stable, easy to store and mass producing, etc. Based on their peroxidase-like activities and unique physicochemical properties, nanomaterials can greatly improve the efficiency and ease of use of ELISA-like detection methods for pathogenic bacteria and viruses. This review introduces recent advances in the application of nanomaterials with peroxidase-like activity for the detection of pathogenic bacteria (both gram-negative bacteria and gram-positive bacteria) and viruses (both RNA viruses and DNA viruses). The emphasis is on the detection principle and the evaluation of effectiveness. The limitations and prospects for future translations are also discussed.

Building a metric of color reproduction difference by combining multiple observers in a modular online experiment

AbstractA web‐hosted online experiment was previously developed to find the visual difference between four reproduction gamuts using direct magnitude estimation (Proc. IS&amp;T 29th Color and Imaging Conf, 2021:317–322). In order to increase the size of the data set, but without overburdening observers, a modular approach was adopted. The original methodology was therefore extended across 10 linked sub‐experiments to make comparisons between some 36 gamuts, which were designed to exhibit a variety of different gamut shapes, contrast ratios, and substrate colors within the constraints of a desktop display. In addition to each set of test images, a common normalization set was included in all sub‐experiments in order to adjust each observer's choice of modulus to a global average observer, and thus combine the results into a larger data set. Finally, an interval scale was inferred from the normalized magnitude data using a categorical judgment approach to calculate scale values. The fitted data revealed a power function close to a square‐root between the interval and magnitude scales.

Effect of withdrawal speed variations on coating quality of electrophoretically deposited biogenic hydroxyapatite on AISI 316L

The use of biogenic waste for multipurpose materials has started to be encouraged in the current decade to support the world’s environmental sustainability campaign. Biogenic calcium phosphate-derived materials are potential biomaterials because of their similar properties to human bone. This paper used hydroxyapatite (HAp) powder derived from green mussel shells (Perna viridis) to coat the AISI 316L metallic implant material using the electrophoretic deposition coating method. In this study, the post-deposition withdrawal speeds of 5mm/s, 3mm/s, and 1mm/s were varied to find their effect on the quality of the HAp coating layer. Crystallography, micrography, and image processing were used to characterize the coating and calculate the percentage of HAp layer and cracks. The crystallographic data shows the HAp peaks, which conclude that the green mussel shells HAp successfully coat the substrate and can be used to coat the AISI 316L implant material. However, the appearance of the substrate crystal peaks and color difference on high withdrawal speed specimens conclude that the coating layer has cracks. In conclusion, the emergence of cracks can be minimized using 1mm/s post-deposition withdrawal speed and eventually produce high-quality HAp coating.

Masking Ability of Monolithic CAD/CAM Laminate Veneers Over Different Resin Cement Shades and Substrate Colors.

To compare the masking ability of monolithic CAD/CAM veneers placed over different resin cement shades and substrate colors. Veneers were milled from four different monolithic CAD/CAM restorative materials: feldspathic ceramic (VMII), lithium disilicate ceramic (Emax CAD), zirconiareinforced lithium silicate ceramic (VS), and high-translucency zirconia ceramic (YZ-XT). Veneers were luted on natural tooth-colored (ND1) or discolored substrates (ND3 or ND5) using two different resin cement shades (opaque white or translucent). Each CAD/CAM material, resin cement shade, and substrate combination comprised 9 sample veneers (N &#61; 216). Color parameters were obtained using a dental spectrophotometer before and after luting. Color differences (ΔE00) were calculated using CIEDE2000 formula and compared to perceptibility (P &#61; .81 ΔE00 units) and acceptability (AT &#61; 1.77 ΔE00 units) visual thresholds. Color variation data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni-Holm correction (α &#61; .05). The highest ΔE00 value was obtained in the VMII group placed over a discolored substrate, followed by the Emax CAD, YZ-XT, and VS groups. The effect of material types on ΔE00 values was significantly observed when the veneers were luted on discolored substrates using translucent resin cement (P < .05). Restorative material type, substrate color, and resin cement shade affect the masking ability of monolithic CAD/CAM laminate veneers.

Selection of substrate type, substrate color, and vegetation by tadpoles of Dryophytes plicatus

The characteristics of microhabitats in streams can drive the distribution of tadpoles. We experimentally examined microhabitat selection of tadpoles of Dryophytes plicatus. We used a series of choice experiments to test if tadpoles had preferences for particular substrate types, substrate colors, and vegetation. Tadpoles of D. plicatus had a strong preference for mud substrates over sand, gravel, and rock substrates and preferred darker substrates over lighter substrates. Dryophytes plicatus tadpoles used the non-vegetated side of an aquarium more than the vegetated side. Our experimental results matched previous field observations in the case of the preference for mud substrates but differed from the field observations for substrate color and vegetation, suggesting that basic underlying preferences may be modified by various factors in nature or by learning or conditioning.

Effects of Ag-doped Content on Antimicrobial Activity and Substrate Color of Chromium Thin Films Deposited by DC Magnetron Sputtering

Silver ions (Ag+) show promise as excellent antimicrobial agents to inhibit microbial growth on high-touch surfaces. In this study, Ag-doped Cr films were deposited using a DC magnetron sputtering system from a mosaic target. The Cr-Ag mosaic target was a 0.125-inch-thick Cr base (99.95% pure) with different diameters of Ag circle sheets mounted on the Cr target. The sputtering condition was kept at a DC power of 100W, working pressure of 8.3x10-3 mbar with Ar as the sputtering gas, and sputtering times of 15 and 30 min. The antimicrobial activity and efficiency were determined by standard testing (JIS Z 2801: 2000). The antibacterial performance was calculated from the antibacterial inhibition of the Ag-doped Cr films in bacterial solution (Staphylococcus aureus and Escherichia coli) after 24 h. The results showed that the Ag content was between 0.27 at% and 6.11 at% depending on the diameter of Ag and the deposition time. The minimum Ag content of 4.05 at% had an inhibition efficiency of 99.98% (E. coli) and 96.33% (S. aureus). The contact angle testing of Ag-doped Cr films showed hydrophobic behavior with the angle greater than 90 degrees. The optical color of the Ag-doped films was characterized by UV-vis spectroscopy (CIE testing). The film colors were significantly changed by the addition of Ag into the Cr films. The total color difference (DE) increased by 3-10 units compared to the reference chromium film and the Ag doping mainly affected +L* (Lightness). Keywords: sputtering PVD; antibacterial agent; silver; mosaic target; ROS; gram-negative; gram-positive; CIE-L*ab *Corresponding author: Tel.: (+66)934598942 E-mail: 62609006@kmitl.ac.th