Colour Change Measurements Research Articles

The effects of microwave and microwave + infrared drying treatments of Pinus brutia and Picea orientalis on water absorption and physical properties

The goal of this study was to find a way to shorten wood drying time by using microwave and combined infrared + microwave drying methods and to analyze color and gloss changes. Wood samples prepared in three groups with dimensions of 20×20×30 mm were used in moisture tests and 75×5×150 mm were used in color change and gloss measurements, obtained from Red pine (Pinus brutia) and Eastern spruce (Picea orientalis) woods. The samples were oven dried, dried by microwave, or dried by infrared + microwave drying method. The wood samples all reached the target moisture. Their weight and volume were calculated in accordance with the principles of TS ISO 13061-1. Color change values were determined before and after drying with a portable color reader (Konica Minolta CR-10) device, and gloss measurements were taken with the Gardner brand gloss meter. By microwave drying for 15 min, 4% moisture content was reached in the wood samples, so both time and energy were saved. The moisture content values decreased compared to the whole drying methods. Most color change was observed in the drying methods using infrared for both red pine and eastern spruce.

Evaluation of the antioxidant potential for three essential oils on the properties of wood pulp paper

Purpose This study aims to determine the efficiency of three types of essential oils (EOs) as antioxidants on wood pulp paper samples: camphor oil, clove oil and lavender oil. Because of the detrimental influence of the oxidation process on wood pulp paper, this type of paper suffers significant disintegration. Design/methodology/approach The evaluation methodology is based on scanning electron microscope and three directions laser microscope, the hydrogen ion concentration measurement, color change measurement using the CIELAB system and infrared spectrum analysis, as well as investigating the mechanical properties of paper as represented by tensile and elongation to determine Young’s modulus values. Findings According to the findings, camphor was an effective antioxidant for paper samples, protecting them from the damaging effects of oxidation and the impact of artificial aging processes while also improving the mechanical properties of paper. Originality/value This paper emphasizes the concept of using environmentally friendly materials derived from EOs, owing to their ease of application, lack of environmental impact, distinctive properties, low cost and distinctive properties in both curative and preventive conservation of paper manuscripts.

Evaluating the Effects of Cigarette Smoking and Heated Tobacco Products on Hard Dental Tissues: A Comparative Histological and Colorimetric Analysis.

This study aimed to evaluate and compare the impact of cigarette smoking (CS) and heated tobacco (HT) on the alteration of color and ultrastructural characteristics of human enamel and cementum. According to tobacco companies, a less harmful substitute for CS is HT products. Nevertheless, comprehensive research on the effects of HT on tooth structures has been lacking. This study aimed to evaluate and compare the impact of CS and HT on the alteration of color and ultrastructural characteristics of human enamel and cementum. Thirty intact and noncarious human maxillary premolars extracted for orthodontic treatment purposes, previously disinfected, were used in the study. The specimens were randomly separated into six groups (n = 10), as follows: Group 1: enamel without smoking exposure; Group 2: enamel exposed to CS; Group 3: enamel exposed to HT; Group 4: cementum without smoking exposure; Group 5: cementum exposed to CS; and Group 6: cementum exposed to HT. The measurement of color change was conducted using a spectrophotometer. The surface alterations and mineral composition of enamel and cementum were evaluated using scanning electron microscopy and energy-dispersive X-ray spectroscopy. ANOVA test followed by Tukey's post hoc test was used to determine significant differences between groups. Results showed that CS had a more pronounced effect on enamel and cementum color changes than HT. The impact of CS and HT on color changes was more evident in cementum than in enamel. Surface morphology of enamel and cementum showed alterations in histology following exposure to both smoking types. Moreover, the mineral content experienced a significant reduction after using CS and HT. The reduction in calcium content after CS and HT exposure was similar. However, HT led to a significant decrease in the phosphorus content of enamel when compared with CS. At the same time, CS exposure in cementum resulted in a more significant reduction in Ca/P ratio than HT. Although HT may appear to present a lower danger to hard dental tissues than CS, it is not entirely harmless. CS results in more color changes on the enamel and cementum of teeth. Both smoking methods affected the mineral content of teeth, with CS having a significant effect on the roots, while HT significantly affected the crowns' mineral composition.

The effect of Pangium edule (kluwek) extract on the discoloration of resin composite microhybrids: an experimental laboratory

ABSTRACTIntroduction: Composite resin is a restoration material that is often used because it has high aesthetic value. Hybrid composite resins are currently one of the most popular materials for aesthetic restoration. This is due to several advantages, including low shrinkage, low abrasion, and better surface smoothness than small-particle composite resins. Pangium edule is a spice used in a variety of dishes, including rawon, brongkos vegetables, and konro soup. Apart from its function as a flavouring, Pangium edule also makes food browner in color. This Kluwekstudy aims to analyze the effect of Pangium edule extract on the discoloration of resin composite microhybrids. Methods: Type of research is experimental laboratory use of 24 microfiller hybrid resin composite specimens with a diameter of 6 mm and a thickness of 2 mm were used. The 24 specimens were divided into three groups based on their soaking time: 1 day, 3 days and 5 days, to see any color changes. Each treatment time group consisted of 8 specimens soaked in the Pangium edule solution. The Vita Easy Shade tool was used to verify color change measurements. Analyzed data using the one-way Anova test Results: The one-way Anova test findings revealed a significant difference (p=0.000) in the color change of composite resin that was soaked in Pangium edule solution for one, three, and five days. Conclusion: The change in the color of microhybrid composite resin soaked in Pangium edule solution for 1 day, 3 days and 5 days can cause color changes, especially in the hue value.KEYWORDSdiscoloration, resin composite microhybrid, Pangium edule

Evaluating the efficacy of probiotic bacterial strain Lactobacillus plantarum for inhibition of fungal strains associated with historical manuscript deterioration: An experimental study

The aim of this study is to develop safe biological methods for controlling fungal deterioration of historical manuscripts. Therefore, fifteen fungal isolates were obtained from paper sheets and leather skins of a deteriorated historical manuscript (dated back to the 13th century). Those isolates were identified using both traditional methods and ITS-sequencing analysis. Aspergillus niger accounted for seven strains, Penicillium citrinum for one strain, Aspergillus flavus for three, Aspergillus fumigatus for one, Aspergillus nidulans for one, and Penicillium chrysogenum for two of the fungal strains that were obtained. The ability of fungal strains for the secretion of cellulase, amylase, gelatinase, and pectinase as hydrolytic enzymes was evaluated. The capability of the probiotic-bacterial strain Lactobacillus plantarum DSM 20174 for inhibition of fungal strains that cause severe deterioration was studied using ethyl acetate-extract. The metabolic profile of the ethyl acetate-extract showed the presence of both high- and low-molecular-weight active compounds as revealed by GC-MS analysis. The safe dose to prevent fungal growth was determined by testing the ethyl acetate extract's biocompatibility against Wi38 and HFB4 as normal cell lines. The extract was found to have a concentration-dependent cytotoxic impact on Wi38 and HFB4, with IC50 values of 416 ± 4.5 and 349.7 ± 5.9 μg mL−1, respectively. It was suggested that 100 μg mL−1 as a safe concentration could be used for paper preservation. Whatman filter paper treated with ethyl acetate extract was used to cultivate the fungal strain Penicillium citrinum AX2. According to data analysis, fungal inhibition measurement, SEM, ATR-FT-IR, XRD, color change measurement, and mechanical property assessment, the recommended concentration of ethyl acetate extract was adequate to protect paper inoculated with the highest enzymatic producer fungi, P. citrinum AX2.

Innovative Materials Based on Epoxy Resin for Use as Seat Elements in Bulk Transport.

The subject of this research is the development of epoxy composites with a defined service life for the purpose of seat elements in rail vehicles, which will be more environmentally friendly. The produced materials based on epoxy resin filled with PLA or PLA and quercetin were subjected to solar aging tests for 800 h to investigate the impact of the additives used on the aging behavior of the epoxy matrix. Firstly, the TGA analysis showed that the use of the proposed additives allowed for the maintenance of the thermal stability of the epoxy resin. Moreover, based on an optical microscopy test, it was noticed that the introduction of PLA and PLA with quercetin did not contribute to an increase in matrix defects. The one-directional tensile tests carried out before and after solar aging showed that the presence of polylactide in epoxy composites causes a slight growth of the stiffness and strength. Based on contact angle and color change measurements, it was found that quercetin was oxidized, thus ensuring protection for the epoxy matrix. This phenomenon was confirmed by FTIR study, where the carbonyl index (CI) value for the R-PLA-Q composite was lower than for the reference sample. The obtained composite structures may be a good alternative to traditionally used systems as seat elements in rail vehicles, which are not only characterized by high aging resistance but are also more eco-friendly.

Evaluation of Cleaning Soiled Deposits and Crusts from Archaeological Glass Using Laser Treatment with Ag/Au Nanoparticles

The study aims to evaluate the effect of silver and gold nanoparticles during the laser cleaning process of glass artifacts. It is the first time that nanoparticles have been used to clean antique glass, as far as the authors are aware. In the context of this study, work was done on glass samples extracted from excavations that suffer from dense layers of corrosion products, soil deposits, brittle, easy to break, and cannot bear pressure. To characterize the investigated glass shards and assess the cleaning procedure, a variety of analytical techniques, including the transmission electron microscope (TEM), digital microscope, stereomicroscope, scanning electron microscope (SEM-EDX), X-ray diffraction (XRD), and color change measurement, have been used. The XRD analysis revealed different minerals such as ferrosilite, hillebrandite, and jacobsite, in the black corrosion layer, and calcite, syngenite, and arcanite in the white crust layer. The results of the microscopic examination employed in the evaluation procedure demonstrated that using Ag NPs with laser perfectly removed the tough crust layers without scratching the surface. The cleaned surface became smooth, homogenous and more transparent. The elemental analysis results by (SEM-EDX) revealed a significant reduction in the proportion elements of the (Al, Fe, p, and Mg) in the corrosion layer and their loss in the cleaned areas. Measurement of color change indicated that laser-treated glass samples with the addition of Ag NPs gave higher (ΔE*), confirming the influential role of this method in cleaning archaeological glass. It was also observed that the effect of Ag NPs with Laser assistance decreases the required time for the cleaning process. Thus the heat generated by the laser-treated was reduced, so the laser-treated with Ag NPs is recommended for use in the archaeological glass cleaning process.

Effect of Child Health Drinks on Color Stability of Various Aesthetic Restorative Materials - An In Vitro Study.

In pediatric dentistry, the esthetically pleasing materials have tremendously changed the concept of restorative practice. 1. The aim of the study is to evaluate the effect of child health drinks on color stability of various esthetic restorative materials via spectrophotometric analysis and to identify the esthetic restorative material that is color-stable against child health drinks. A total of 120 disk-shaped specimens with a diameter of 12 mm and a thickness of 2 mm were made from a composite (Dyract), giomer (Shofu), and composite (GC). Each group of 40 specimens of each material was divided into four sub-groups. Each sub-group was stored in different solutions, distilled water, Bournvita, Horlicks, and Pediasure, for 60 days. The color change measurement was done using a spectrophotometer both before and after staining. One-way analysis of variance depicted that when the ΔE values of the restorative material were tested against each of the child health drink, there was a statistically significant difference between all child health drinks (P < 0.00001). When restorative materials were compared with the staining agent on 60 days duration, except Pediasure and Control, others (i.e. Horlicks and Bournvita) showed a statistically high significance (P < 0.05). Bournvita caused the highest color changes in 60 days time interval, followed by Horlicks and Pediasure. When the discoloration of several materials is studied, the highest level of discoloration was observed in the compomer, followed by the giomer, and the lowest level in the composite.

Dental color measurement to estimate age in adults: a systematic review and meta-analysis.

Age estimation is a major challenge in anthropology and forensic odontology laboratories, as well as in judicial settings, as one of the tools used in human identification. The aim of this study was to evaluate the usefulness of age estimation methods based on the accurate measurement of tooth color changes. A systematic review was carried out following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and in compliance with Cochrane criteria recommendations (PROSPERO registration number CRD 42022343371). An electronic search was performed in the following databases: Pubmed, Web of Science, Medline, Current Contents Connect, SciELO, KCI-Korean Journal Database, Derwent Innovations Index and Russian Citation Index. The search strategy yielded a total of 18 articles. A randomized meta-analysis model of the results for the CIE L*a*b* color variables stratified by age (less than 30 years, 30-60 years, 60 years and older) was performed with 9 of the 18 studies included in this systematic review. According to our results, sex and location of color measurement are the most influential factors in color estimation. All studies were carried out in healthy anterior teeth by spectrophotometry as the most commonly used method for color measurement, with CIE L*a*b* being the most commonly analyzed parameters. Studies based on age as a dependent variable showed R2 values between 0.28 and 0.56, being higher in ex vivo teeth. Studies based on age as an independent variable showed R2 values ranging from 0.10 to 0.48. The random model showed high heterogeneity for the L*, a* and b* parameters in all age groups, which is explained by discrepancies in age range and non-standardized conditions for color measurement. This systematic review highlights the need to protocolize age estimation studies that measure tooth color, in order to apply this method in different forensic settings.

Investigation of TiO2 replacement alternatives for water-based paints using styrene butyl acrylate

Purpose Titanium dioxide (TiO2) has high opacity, high brightness and whiteness, owing to its high refractive index value. It is mainly used in the coating industry and continuous efforts have been made to replace some of the TiO2 in paint with new pigments. This study aims to replace part of TiO2 pigment with various percentages of BaSO4, CaCO3 and kaolin in styrene butyl acrylate-based paint formulations, without changing the properties of paints using only titanium dioxide. Design/methodology/approach To determine the optimum use rate of new pigment mixing, opacity, gloss, scrub resistance and weather resistance properties have been investigated in the water-based paint formulation. The morphological properties of these samples were examined by scanning electron microscopy analysis. Findings In the total color change (ΔE) measurements, it was observed that the sample coded 85Ti/15Ba produced extremely similar results to the situation when TiO2 was used alone. It was seen that the best results were obtained when 85Ti/15Ba was used instead of TiO2. Originality/value Comparison research on the impact of replacing TiO2 with BaSO4, CaCO3 and kaolin on the performance characteristics of water-based styrene butyl acrylate-based paint formulations has not been done in the literature, according to the literature search.

The Effect of Bleaching Agents on Color Change in Different Section Shapes in Beech And Fir Woods

Aim of study: It is an investigation of the effects of bleaching processes on the color change in the wood of tree species. Tree species Eastern Beech (Fagus Orientalis Lipsky.) and Eastern Black Sea Fir (Abies Nordmanniana subsp.) were used in the study. Sodium hydroxide-hydrogen peroxide, oxalic acid, peracetic acid diluted 1/3, peracetic acid diluted 1/6 were used as bleaching agents. Trial samples were prepared in accordance with standards and color change measurements were made.&#x0D; Area of study: Surface treatments on wooden materials&#x0D; Material and methods: In the study, two wood species and one varnish type were used; Color changes were tested by applying various bleaches to the wooden material by rubbing method.&#x0D; Main results: As a result of the study, differences were observed in all cross-section shapes in beech wood bleaching measurements with 1/6 diluted peracetic acid, and differences were observed in cross-section shapes in fir wood bleaching measurements. The best bleaching of fir wood was achieved with peracetic acid.&#x0D; Main results: As a result of the study, differences were observed in all cross-section shapes in the beech wood bleaching measurements with 1/6 diluted peracetic acid, and in the cross-section shapes in the fir tree bleaching measurements. The best bleaching of fir wood was achieved with peracetic acid.&#x0D; Highlights: The bleaching process allows the wooden material to easily acquire a homogeneous color. Since the cell arrangements are different in different cross-sectional shapes, the bleaching rates are different from each other. While there is not much difference in the color changes in the wood material when bleached with oxalic acid, the samples are bleached as a result of bleaching with sodium hydroxide-hydrogen peroxide and peracetic acid. Significant changes have occurred in color changes. The reason for this difference is due to the different degrees of corrosion of bleaching agents.

Effect of Coffee and Polishing Systems on the Color Change of a Conventional Resin Composite Repaired by Universal Resin Composites: An In Vitro Study.

The purpose of this study was to evaluate the color stability of repaired aesthetic restorative resin matrix materials after immersion in coffee and the effect of polishing systems after staining. One hundred and eighty cylindrical discs (8 mm × 2 mm) were prepared using a conventional nano-fill resin composite (Clearfil Majesty Esthetic A2 shade) with round cavities (3 × 1 mm). Cavities were repaired by three resin composite materials: Clearfil Majesty Esthetic A2 shade, one-shaded nano-fill resin composite (Omnichroma) and group-shaded nano-hybrid resin composite (Optishade, medium shade). Each group was polished with three polishing systems (n = 20); aluminum oxide (Soflex Spiral Wheels, 3M ESPE), silicon carbide (Occlubrush, Kerr, CA, USA) and diamond particulate (Twist Dia Spiral Wheels, Kuraray, Okayama, Japan). Color change (ΔE00) measurements were performed with a spectrophotometer at the baseline. Half of the polished samples were either kept in distilled water or immersed in coffee for 15 days, and color measurements were repeated before and after polishing. Statistical analysis was performed using the Kruskal-Wallis test. Repaired samples showed different color correspondence values in all groups. All three restorative materials showed significant color changes (ΔE00) after immersion in coffee (p ≤ 0.05). Repolishing of stained samples showed color improvement values in all groups. The content of the polishing system played an important role in removing the stains.

The Effect of Different Surface Treatments on the Color Stabilities of Lithium Disilicate Material

Background: The aim of this study is to investigate the clinical acceptability of the color change that may occur in time about full ceramic materials used for aesthetic restorations, which are bonded after different surface conditioning processes, by measuring with spectrophotometer.&#x0D; Methods: The lithium disilicate CAD material we used in our work was prepared with isomet in the form of 1-millimeter-thick specimens. Three random groups of 21 specimens were selected from the specimens. One of these groups was conditioned with phosphoric acid, which is recommended by the manufacturer. Er:YAG laser was applied to the second group. The third group was conditioned by Nd:YAG laser. Surface changes in the groups were evaluated by scanning electron microscope (SEM) and atomic force microscope (AFM). The specimens were bonded with the adhesive resin cement to the background material for color change measurement. The first color measurement of the bonded specimens was done by spectrophotometer. The specimens were aged at 10,000 cycles in the thermal cycle device. The second color measurement after aging was done with the same spectrophotometer. &#x0D; Results: After aging with thermal cycle, there was a clinically acceptable color change in all groups. The Nd:YAG laser group presented better color stability (p

Evaluation of Color Stability and Remineralization Capacity of Dual Effect Desensitizing Agents on Bleached Enamel with Hydrogen Peroxide

Objectives:To evaluate the effects of double-acting desensitized varnishes applied to bovine tooth enamel bleached with 40% hydrogen peroxide on enamel calcium and phosphorus content and color stability. Materials and Methods:The coronal part of 10 newly extracted bovine teeth (approximately 10x12mm in size) was divided into 5 regions for mineral exchange measurements. Color change measurements of 50 newly extracted bovine teeth were divided into 5 groups. Group 1 unbleached (negative control group), Group 2 was bleached with 40%HP (positive control group), Groups 3,4 and 5 were treated MI varnish, Clinpro White and Profluoroid varnish after bleaching, respectively. Then, all groups were exposed to the tea solution and enamel color measurements were made using the CIE Lab method with spectrophotometer. Mineral change measurements were determined by EDS and morphological changes were observed using SEM. One-way ANOVA, Tukey HSD tests and Tamhane's tests were used for statistical analysis. Results:The content of calcium and phosphorus in enamel were like No bleachingMI varnishClinpro WhiteProfluoroidBleaching. The most color stability after bleaching was determined in teeth which were applied MI varnish applied group ((P&amp;lt; .05). The color stability of Profluoroid and Clinpro White applied group were similar (P&amp;gt; .05). There was a statistically significant difference between the groups in terms of △L and △b averages (P&amp;lt; .05). Conclusions:MI, Clinpro White and Profluoroid varnish used after bleaching were effective in preventing mineral loss from tooth enamel and reducing the susceptibility of tooth enamel to staining with tea.

Analysis of the aging and stabilization processes in cyclic polyolefins containing various natural or synthetic stabilizers

The aim of this research was to perform a new evaluation of stabilizers dedicated to ethylene-norbornene copolymer (EN). The aging and stabilization processes of the EN polymer filled with natural (xanthone, naringenin) or synthetic (Rianox 626, Rianox 1726, Rianox 3114) antioxidants with different chemical structure were thoroughly analyzed and the suitability of the methods described in the literature to study these processes was assessed. EN is successfully used in optics, electronics or packaging sectors, but like any other organic material, it will degrade under the influence of environmental factors. The EN films were subjected to thermo- and photooxidation for 150, 300, 450, and 600 h. We observed that all composites exhibited an excellent resistance to thermo-oxidation, but as expected, much greater differences were noted after exposure to ultraviolet radiation. The performed tests: thermal analysis, FTIR spectroscopy, contact angles determination, color change measurements, static and dynamical mechanical tests proved the high effectiveness of the used antioxidants for the EN stabilization. However, in the case of the EN-xanthone sample, during the FTIR analysis, a higher value of the carbonyl index in comparison with the reference EN was obtained, and a greater change in the glass transition temperature (Tg) compared to the other used stabilizers was observed. These changes could be caused by xanthone oxidation on the polymer surface and its plasticization because of aging, as evidenced by the increased Tg value. In addition, we also discussed possible stabilization mechanisms of EN through the use of selected antioxidants. Interestingly, based on the obtained results, Rianox 626 containing phosphite groups in its structure turned out to be the most effective stabilizer for the ethylene-norbornene copolymer, even though it is a secondary antioxidant. It can therefore be suggested that the propagation stage plays a leading role in the degradation of this polymer, in which antioxidants decompose hydroperoxides. In the case of Rianox 626, phosphite groups reacted with hydroperoxides, thus creating the phosphate form of this stabilizer and alcohols, which are more stable and non-radical products.

Use of Digital Images as a Low-Cost System to Estimate Surface Optical Parameters in the Ocean

Ocean color is the result of absorption and scattering, as light interacts with the water and the optically active constituents. The measurement of ocean color changes enables monitoring of these constituents (dissolved or particulate materials). The main objective of this research is to use digital images to estimate the light attenuation coefficient (Kd), the Secchi disk depth (ZSD), and the chlorophyll a (Chla) concentration and to optically classify plots of seawater using the criteria proposed by Jerlov and Forel using digital images captured at the ocean surface. The database used in this study was obtained from seven oceanographic cruises performed in oceanic and coastal areas. Three approaches were developed for each parameter: a general approach that can be applied under any optical condition, one for oceanic conditions, and another for coastal conditions. The results of the coastal approach showed higher correlations between the modeled and validation data, with rp values of 0.80 for Kd, 0.90 for ZSD, 0.85 for Chla, 0.73 for Jerlov, and 0.95 for Forel-Ule. The oceanic approach failed to detect significant changes in a digital photograph. The most precise results were obtained when images were captured at 45° (n = 22; Fr cal=11.02>Fr crit=5.99). Therefore, to ensure precise results, the angle of photography is key. This methodology can be used in citizen science programs to estimate ZSD, Kd, and the Jerlov scale.

Cuttlefish color change as an emerging proxy for ecotoxicology.

Lately, behavioral ecotoxicology has flourished because of increasing standardization of analyses of endpoints like movement. However, research tends to focus on a few model species, which limits possibilities of extrapolating and predicting toxicological effects and adverse outcomes at the population and ecosystem level. In this regard, it is recommended to assess critical species-specific behavioral responses in taxa playing key roles in trophic food webs, such as cephalopods. These latter, known as masters of camouflage, display rapid physiological color changes to conceal themselves and adapt to their surrounding environments. The efficiency of this process depends on visual abilities and acuity, information processing, and control of chromatophores dynamics through nervous and hormonal regulation with which many contaminants can interfere. Therefore, the quantitative measurement of color change in cephalopod species could be developed as a powerful endpoint for toxicological risk assessment. Based on a wide body of research having assessed the effect of various environmental stressors (pharmaceutical residues, metals, carbon dioxide, anti-fouling agents) on the camouflage abilities of juvenile common cuttlefish, we discuss the relevance of this species as a toxicological model and address the challenge of color change quantification and standardization through a comparative review of the available measurement techniques.

Protein Determination by Distance and Color Changing &lt;i&gt;via&lt;/i&gt; PEG-Based Hydrogels

Equipment-free detection devices are attractive for point-of-care analysis, especially in resource-limited regions. Distancebased detection is the measurement of color change along the detection path related to the concentration of analytes. Hydrogels are three-dimensional crosslinked polymer networks with tunable properties and may be suitable for distance-based sensors. However, only small ions have been used as the targets in the previous studies. In this work, we demonstrated the possibility of using hydrogel as the distance-based measurement of large biomolecules such as proteins. The hydrogel was prepared with poly(ethylene glycol) diacrylate and a fluorescein derivative as the fluorescent detection probe. The fluorescent alteration in the presence of a target protein, trypsin, can be observed in both intensity-based and distance-based detection. It was found that the effect of the concentration of a fluorescent reagent was not significantly impacted in distance-based detection, while it is essential in intensity-based detection. The relationship between the distance change and the trypsin concentration in the range of 0.5 – 5 mM can be observed. This result showed the possibility of using hydrogel for distance-based detection of large biomolecules.

Chromophoric cerium oxide nanoparticle-loaded sucking disk-type strip sensor for optical measurement of glucose in tear fluid

BackgroundNoninvasive monitoring of tear glucose levels can be convenient for patients to manage their diabetes mellitus. However, there are issues with monitoring tear glucose levels, such as the invasiveness of some methods, the miniaturization, inaccuracy, or the high cost of wearable devices. To overcome the issues, we newly designed a sucking disk-type (SD) strip biosensor that can quickly suck tear fluid and contains cerium oxide nanoparticle (CNP) that causes a unique color change according to the glucose level of the tear without complicated electronic components.MethodsThe SD strip biosensor composed of three distinct parts (tip, channel, and reaction chamber) was designed to contain the sensing paper, onto which tear fluid can be collected and delivered. The sensing paper treated with CNP/APTS (aminopropyltriethoxysilane) /GOx (glucose oxidase) was characterized. Then we carried out the reliability of the SD strip biosensor in the diabetic rabbit animals. We quantitatively analyzed the color values of the SD strip biosensor through the colorimetric analysis algorithm.ResultsWe contacted the inferior palpebral conjunctiva (IPC) of a diabetic rabbit eye using an SD strip biosensor to collect tears without eye irritation and successfully verified the performance and quantitative efficacy of the sensor. An image processing algorithm that can optimize measurement accuracy is developed for accurate color change measurement of SD strip biosensors. The validation tests show a good correlation between glucose concentrations measured in the tear and blood.ConclusionOur findings demonstrate that the CNP-embedded SD strip biosensor and the associated image processing can simply monitor tear glucose to manage diabetes mellitus.Graphical

The Effect of Polishing, Glazing, and Aging on Optical Characteristics of Multi-Layered Dental Zirconia with Different Degrees of Translucency.

(1) Background: Considering that the appearance of a dental material is an important factor that contributes to the success of prosthetic restorations. The purpose of this study is to investigate the optical properties and color changes among the layers of three commercial zirconias, to compare the aspect of the polished and glazed surfaces before and after aging and to evaluate the effects of hydrothermal degradation on their aesthetics. (2) Methods: Forty-eight plate-shaped samples were sectioned from presintered blocks of each multilayer translucent zirconia with different Yttrium content: Ceramill Zolid fx ML (5 mol%) = CeZ, STML (4 mol%) = STM, IPS e.maxZirCAD CEREC/in Lab MT Multi (4 mol% + 5 mol%) = IPZ. The samples were sintered according to the recommendation of each manufacturer, and half (24) of them were polished and the other half (24) glazed on one of the surfaces. Each type was equally divided into one control and one aging group, and, for each material, this resulted in four groups (n = 12): polished-control, polished-autoclaved glazed-control, and glazed-autoclaved. The artificial aging was carried out with an autoclave and distilled water at 134 °C, 0.2 MPa for 1 h, and for optical parameters (TP, CR, OP) and color change (ΔE*) measurements on a black and white background in a CIE L*a*b* color system, a spectrophotometer was used. The specimens were evaluated in incisal, cervical, and medium areas on polished and glazed samples before and after the aging stage. Statistical analysis was achieved with a two-way ANOVA test, the unpaired t-test, and the paired t-test. (3) Results: Before and after aging, the mean TP values for polished samples were higher than the glazed ones. After aging, the mean TP values increased for all groups (except polished CeZ), and significant differences were reported for polished STM, IPZ. After LTD, the opalescence registered an increase for almost all groups (except polished CeZ, polished and glazed IPZ-medium area), and significant differences were reported for almost all groups (except STM-incisal, IPZ-cervical, medium areas). The levels of color change were between extremely slight to perceivable. (4) Conclusions: Optical properties of the selected multilayer zirconia were influenced by polishing and glazing as surface treatment and affected by artificial aging (CeZ the least); perceivable color changes for polished STM, IPZ were detected.