Intensity Of Color Change Research Articles

Impact of the architecture of dye sensitized solar cell-powered electrochromic devices on their photovoltaic performance and the ability to color change

The functional layers arrangement in a dye sensitized solar cell electrochromic device (DSSC-EC) on the energy conversion efficiency and on the ability to change the color is studied. The highest power conversion efficiency of ca. 7% and good color change in closed circuit conditions was observed with electrochromic WO3 deposited on the counter-electrode of the DSSC. When WO3 layer was applied over the photoanode, the DSSC-EC displayed less power conversion efficiency − 3.4%, but a more intense color change was observed under illumination and opened external circuit.Response of the photocurrent vs. applied potential, incident photon-to-current conversion efficiency and optical behavior of the DSSC-EC were assessed and discussed considering optical properties of the components of the device and their energy bands alignment. Smart window and self-powered proof-of-concept pixelated device operating on DSSC-EC are presented.

Color Characteristics of Red False Heartwood and Mature Wood of Beech (Fagus sylvatica L.) Determining by Different Chromacity Coordinates

Structure of wood can affect intensity of color change in remarkable ways. This article was focused on the analysis of the color changes red false heartwood and mature wood by different methods such as ΔE* (Total color difference), h* (Hue angle), C*ab (Color saturation) and Sab (Saturation). The aim of this study was to evaluate the color properties of red false heartwood and mature wood by using different chromacity coordinates. Our observations suggested that the density in the absolute dry state was equal between the red false heartwood and mature wood. The biggest difference was in the area of the free water domain, thus from an initial MC value to the fiber saturation point (FSP). The shorter drying time of the red false heartwood samples was caused by their lower initial MC. Due to the different MC, the temperature created a different color intensity of the compared samples. Mature wood samples achieved more saturated color in the drying process than did the samples of red false heartwood.

Color changes kinetics during deep fat frying of kohlrabi (Brassica oleracea var. gongylodes) slice

ABSTRACT Kohlrabi is used for consumption in various regions of the world as, raw, cooked or fried. Heat and mass transfer phenomena take place during frying cause physicochemical changes, which affect the color and surface of the fried products. The effect of frying temperature on the color changes and center temperature change during deep fat frying of kohlrabi was investigated. The color scale parameters redness (a*), yellowness (b*) and lightness (L*), and color change intensity (∆E) were used to estimate color changes during frying as a function of oil temperature and time. L* value of fried kohlrabi decreased during frying but a* and b* values were increased. A first-order kinetic equation was used for each one of the three color parameters, in which the rate constant is a function of oil temperatures. The results showed that oil temperature has a significant effect on the color parameters. Different kinetic models were used to fit the experimental data, and the results revealed that the power model was the most suitable to describe the color change intensity (∆E). Center temperature of kohlrabi slice increased with an increase in oil temperature and time during frying.

Tissue-mimicking thermochromic phantom for characterization of HIFU devices and applications

Purpose: Tissue-mimicking phantoms (TMPs) are synthetic materials designed to replicate properties of biological tissues. There is a need to quantify temperature changes following ultrasound or magnetic resonance imaging-guided high intensity focused ultrasound (MR-HIFU). This work describes development, characterization and evaluation of tissue-mimicking thermochromic phantom (TMTCP) for direct visualization and quantification of HIFU heating. The objectives were to (1) develop an MR-imageable, HIFU-compatible TMTCP that reports absolute temperatures, (2) characterize TMTCP physical properties and (3) examine TMTCP color change after HIFU.Methods and materials: A TMTCP was prepared to contain thermochromic ink, silicon dioxide and bovine serum albumin (BSA) and its properties were quantified. A clinical MRI-guided and a preclinical US-guided HIFU system were used to perform sonications in TMTCP. MRI thermometry was performed during HIFU, followed by T2-weighted MRI post-HIFU. Locations of color and signal intensity change were compared to the sonication plan and to MRI temperature maps.Results: TMTCP properties were comparable to those in human soft tissues. Upon heating, the TMTCP exhibited an incremental but permanent color change for temperatures between 45 and 70 °C. For HIFU sonications the TMTCP revealed spatially sharp regions of color change at the target locations, correlating with MRI thermometry and hypointense regions on T2-weighted MRI. TMTCP-based assessment of various HIFU applications was also demonstrated.Conclusions: We developed a novel MR-imageable and HIFU-compatible TMTCP to characterize HIFU heating without MRI or thermocouples. The HIFU-optimized TMTCP reports absolute temperatures and ablation zone geometry with high spatial resolution. Consequently, the TMTCP can be used to evaluate HIFU heating and may provide an in vitro tool for peak temperature assessment, and reduce preclinical in vivo requirements for clinical translation.

Electrochromic 2,4,6-triphenyl-1,3,5-triazine based esters with electron donor-acceptor structure

Abstract Ten tripod-shaped electrochromic materials (compound 1–10) were designed and synthesized by esterification of 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoic acid with different alcohols and phenols. These materials have a 2,4,6-triphenyl-1,3,5-triazine core and three ester side arms, forming an electron donor–π-acceptor structure. The electrochemical and optical properties of 1–10 were characterized by cyclic voltammetry and ultraviolet–visible spectroelectrochemistry. The conjugated structure of 1–10 markedly influenced their electrochemical properties. Electrochromic devices containing some of these compounds (1, 2, 4, 5, and 10) displayed intense color changes, fast switching times ( 60%), good switching stability, high optical density (>1.0), and high coloring efficiency (>1000 cm2 C−1). The colored state of these devices strongly depended on the conjugated structure of the tripod-shaped component. Short chain lengths (compounds 1 and 2) and electron-donating groups (compounds 4, 5, 8, and 10) were beneficial to electrochromic properties, whereas a longer chain length (compound 3) and electron-withdrawing groups (compounds 6 and 9) adversely affected electrochromic properties.

Design, synthesis, crystal structure and cytotoxicity studies of colorimetric fluorescent “OFF-ON” probes for rapid detection of hydrogen sulfide based on Cu(II) complex

Four colorimetric fluorescent probes based on copper(II) complexes were synthesized and the molecular structures were characterized by X-ray diffraction, ESI-HRMS and elemental analysis. When exposed to HS−, the synthesized probes showed significant color changes from yellow to red and remarkable increase of fluorescence intensity (over 80-fold). What's more, the interaction of host-guest could be completed in 2 min. However, no clear color and fluorescence intensity changes were observed in the presence of other anions (AcO−, H2PO4−, F−, Cl−, Br−, I−, SO42−, SO32−, CO32−, Cys and GSH). The synthesized colorimetric fluorescent probes could detect HS− rapidly and conveniently. Cytotoxicity studies indicated that the synthesized fluorescent probes were low cytotoxicity in Hela cells and may be used to detect H2S level in vivo.

A colorimetric assay system for dopamine using microfluidic paper-based analytical devices

We report the colorimetric detection of dopamine (DA) on microfluidic paper-based analytical devices (μPADs) using an oxidation-reduction method. Here, dopamine reacts with ferric chloride forming reduced Fe2+ that subsequently reacts with phenanthroline to form the red tris(1,10-phenanthroline)iron(II) complex. The devices were fabricated by wax printing and changes in color intensity were recorded using a common cell phone. Subsequent analysis using Photoshop software, yielded a limit of detection (LOD) for DA of 0.37 μmol/L with a linear range of 0.527–4.75 μmol/L and relative standard deviation of 0.11% (inter-day) and 0.15% (intra-day) for n = 15 paper chips. The effects of detection conditions have been investigated and are discussed. Cow serum samples and human blood serum and plasma samples were detected. The work, herein, demonstrates the potential of this method as a low cost and rapid colorimetric technique to detect DA in real samples.

Colorimetric point-of-care detection of cholesterol using chitosan nanofibers

Recent developments in biosensor-related research have provided economic and highly sensitive biosensors for numerous biological analytes. Several strategies have evolved for developing a sensitive biosensor for cholesterol detection. In this study, we have developed a point-of-care, chitosan nanofiber-based cholesterol biosensor, involving colorimetric detection of the analyte. Chitosan nanofibers, fabricated using electrospinning, were utilized for immobilizing cholesterol oxidase and peroxidase enzymes. A uniform and bead-free chitosan nanofibers were obtained using chitosan and polyvinyl alcohol (Cs: PVA), at the ratio of 0.7:1 w/w, in a solvent system containing 10%v/v of methanol in 63% acetic acid. The nanofibers were characterized using scanning electron microscopy (SEM), which revealed the formation of smooth fibers, with an average diameter of 60–90 nm. The fabricated nanofibers offered a greater surface area for immobilizing high quantities of enzymes and demonstrated the potential to be developed into a strip-based intervention, based on a simple, visual detection system. A colorimetric detection method was developed using the chromogenic substrate, 3,3́,5,5́-tetramethylbenzidine hydrochloride. Analysis by UV–vis spectrophotometry demonstrated a linear increase in the absorbance, with increasing concentrations of cholesterol. The intensity of color change, as a function of cholesterol concentration was used for developing a color gradient scale for the investigated biosensor.

Impact of a commercially available ion-exchange resin used in red wines to reduce toxic compounds: effect on pH, oxidation–reduction potential, color, and sensory attributes

This research was performed to evaluate the impact of a novel ion-exchange treatment on the organoleptic, pH, color (hue and intensity), and oxidation-reduction potential (ORP) properties of commercial red wines. The ion-exchange treatment used in this study is a commercially available device containing a double cation-anion exchange resin. The device is applied, directly by the consumer, to finished bottled wines with the purpose of mitigating the effects of potentially noxious compounds such as biogenic amines and sulfites. Sensory evaluation tests included discriminative, affective, and Quantitative Descriptive Analysis sensory tests were employed to evaluate the impact on the perceived taste of treated wines. The pH, ORP and color parameters (hue and intensity) of wines were measured to assess any physicochemical alterations that may help to explain the results of the sensory evaluation. While no significant changes in color hue or intensity were found, the results showed a reduction in pH (0.07-0.12) and an increase in ORP (2.667-6.666mV). However, the changes in pH and ORP did not result in a detectable change in wine taste for the sensory panelists. These findings have important implications for the wine industry, where many consumers select wines for their characteristic taste qualities. Thus, any treatment to potentially remove noxious compounds should not impact the characteristic organoleptic properties of a chosen wine.

Pellet patented technology for fast and distinct visual detection of cholinesterase inhibitors in liquids

The main objective of the presented research was to prepare an innovative carrier as a filler for detection tubes in the form of double-coated pellets with a very significant color transition during the detection of cholinesterase inhibitors such as nerve agents, organophosphorus or carbamate insecticides in liquids that is observable visually and also spectrophotometrically at 412 nm. The pellet cores were prepared by the extrusion/spheronization method. Consecutively, two different coats were applied on the pellet cores in the coating device using the Wurster column method. To increase the color change intensity, the second semipermeable coat based on Eudragit® RL was applied on top of the first coat, which was formed by butyrylcholinesterase immobilized in hydroxypropyl methylcellulose. Prepared samples differing in thickness of the second coat were evaluated for their quality parameters, enzymatic activity and inhibition. The detection mechanism was based on the standard Ellman’s colorimetric reaction. It was observed that the semipermeable coat prevented leaching of the enzyme into the solution and led to an increased intensity of color transition from white – yellow to white – deep yellow/orange, thus enabling a more accurate visual detection. This system allows easy, rapid and safe identification of cholinesterase inhibitors in liquids, especially chemical warfare agents.

Chemical stability and reaction kinetics of two thiamine salts (thiamine mononitrate and thiamine chloride hydrochloride) in solution

Two types of thiamine (vitamin B1) salts, thiamine mononitrate (TMN) and thiamine chloride hydrochloride (TClHCl), are used to enrich and fortify food products. Both of these thiamine salt forms are sensitive to heat, alkali, oxygen, and radiation, but differences in stability between them have been noted. It was hypothesized that stability differences between the two thiamine salts could be explained by differences in solubility, solution pH, and activation energies for degradation. This study directly compared the stabilities of TMN and TClHCl in solution over time by documenting the impact of concentration and storage temperature on thiamine degradation and calculating reaction kinetics. Solutions were prepared containing five concentrations of each thiamine salt (1, 5, 10, 20, and 27 mg/mL), and three additional concentrations of TClHCl: 100, 300, and 500 mg/mL. Samples were stored at 25, 40, 60, 70, and 80 °C for up to 6 months. Degradation was quantified over time by high-performance liquid chromatography, and percent thiamine remaining was used to calculate reaction kinetics. First-order reaction kinetics were found for both TMN and TClHCl. TMN degraded significantly faster than TClHCl at all concentrations and temperatures. For example, in 27 mg/mL solutions after 5 days at 80 °C, only 32% of TMN remained compared to 94% of TClHCl. Activation energies and solution pHs were 21–25 kcal/mol and pH 5.36–6.96 for TMN and 21–32 kcal/mol and pH 1.12–3.59 for TClHCl. TClHCl degradation products had much greater sensory contributions than TMN degradation products, including intense color change and potent aromas, even with considerably less measured vitamin loss. Different peak patterns were present in HPLC chromatograms between TMN and TClHCl, indicating different degradation pathways and products. The stability of essential vitamins in foods is important, even more so when degradation contributes to sensory changes, and this study provides a direct comparison of the stability of the two thiamine salts used to fortify foods in environments relevant to the processing and shelf-life of many foods.

Modeling of moisture loss kinetics and color changes in the surface of lemon slice during the combined infrared-vacuum drying

Color is one of the most important appearance attributes of food materials, since it influences consumer acceptability. In this study the effects of combined infrared-vacuum drying on the drying kinetics, moisture diffusivity, surface changes (shrinking) and color changes kinetics of lemon slices were investigated. Both the infrared lamp power and vacuum pressure influenced the drying time of lemon slices. The regression results showed that the quadratic model satisfactorily described the drying behavior of lemon slices with highest R value and lowest SE values. The effective moisture diffusivity increased from 2.92 × 10−10 and 1.58 × 10−9 m2/s when the infrared lamp power was increased from 300 to 400 W. The colour parameters L∗ (lightness), a∗ (redness/greenness), b∗ (yellowness/blueness), and ΔE (total colour difference) were used to estimate colour changes during drying. L∗, a∗ and b∗ values of dried lemon increased during drying. The rise in infrared power has a negative effect on the ΔE and with the increase of infrared radiation power it was increased. Different kinetic models were used to fit the experimental data and the results revealed that the power model was the most suitable to describe the color change intensity (ΔE).

Color changes kinetics during deep fat frying of carrot slice

Heat and mass transfer phenomena take place during frying cause physicochemical changes, which affect the colour and surface of the fried products. The effect of frying temperature on the colour changes and heat transfer during deep fat frying of carrot has been investigated. The colour scale parameters redness (a*), yellowness (b*) and lightness (L*), and color change intensity (∆E) were used to estimate colour changes during frying as a function of oil temperature. L* value of fried carrot decreased during frying. The redness of fried carrot decreased during the early stages of frying, while it increased afterwards (become more red). A first-order kinetic equation was used for each one of the three colour parameters, in which the rate constant is a function of oil temperatures. The results showed that oil temperature has a significant effect on the colour parameters. Different kinetic models were used to fit the experimental data and the results revealed that the quadratic model was the most suitable to describe the color change intensity (∆E) (R > 0.96). Center temperature of carrot slice increased with increase in oil temperature and time during frying.

Effect of storage period on special DUS characters in extant varieties of rice (Oryza sativa) for establishing distinctiveness

Under the PPV and FR Act 2001, a number of rice varieties have been registered based on morphological and biochemical DUS descriptors. In the present study, 61 extant varieties of rice (Oryza sativa L.) were characterized based on 55 morphological descriptors at different stages of plant growth. However, for the assessment of biochemical characters, namely; phenol reaction of lemma, amylose content and gelatinization temperature, the assessment is based on ripened seed onwards, and even after the seed is stored. Hence, there is a need to determine optimum period after seed ripening for recording biochemical characters to avoid confusion during grouping of varieties for establishing distinctiveness. For this, all the 61 varieties were examined to see the effect of storage period on biochemical characters. The observations were recorded beginning from freshly harvested seed (0 months) vis-Ã -vis stored seed up to one year (12 months). The data were recorded after every three months up to a period of one year. Results revealed that significant changes begin to occur during six months of storage and continue for remaining period. Phenol reaction of lemma colour in 26 varieties showed significant changes in colour intensity after six months of storage. Gelatinization temperature (GT) and amylose content are important cooking quality traits for rice. Among 61 varieties, 26 showed increase in Gelatinization temperature after six months of storage as ASV decreased from 6.7 to 6.0, while the remaining varieties showed constant ASV. Further, the average percentage of amylose content significantly increased after six months of storage period in all varieties. Hence, storage period significantly influences the character expression of biochemical traits. Therefore, it is recommended that the varieties should be evaluated for the biochemical assessment within six months of harvesting.

Mass Transfer and Color Changes Kinetics of Infrared-Vacuum Drying of Grapefruit Slices

ABSTRACTThe effects of combined infrared-vacuum drying parameters, including infrared power (300–400 W), pressure (5–25 kPa) and time (0–140 min) on the drying kinetics of grapefruit slices were investigated. Both the infrared lamp power and vacuum pressure influenced the drying time of grapefruit slices. The regression results showed that the quadratic model satisfactorily described the drying behavior with highest R and lowest SE values. The effective moisture diffusivity increases as power increases and range between 5.83 × 10–10 and 2.13 × 10–9 m2/s. The color scale parameters, including redness (a*), yellowness (b*) and lightness (L*) values of dried grapefruit slices increased during drying. The rise in infrared power has a negative effect on the color change intensity (∆E) and with increasing in infrared radiation power it was increased. Different kinetic models were used to fit the experimental data and the results revealed that the power model was the most suitable to describe the ∆E.

Implication of regional brain serotonergic neurons in dorsal and median Raphé nuclei in adaptation to water lacking in Gerbillus tarabuli

The objective of this work was to investigate the implication of serotonin (5-HT) produced in the dorsal and medial raphé nuclei (DRN and MRN) in water homeostasis in desert animal Gerbillus tarabuli. For that, we measured the density of 5-HT immunolabeled neurons in hydrated and dehydrated animals (over 1 and six months). In this work, 5-HT positive neurons showed some change in shape and colour intensity in dehydrated gerbils comparing with hydrated gerbils. Furthermore a differential increase of 5-HT neurons density was observed in DRN subregions and in MRN following 1 and 6 months of dehydration.This study suggested that neurons in DRN and MRN contain 5-HT in various amounts, thus allowing an adapted response to hydration status. These neurons could mediate one of the adaptation mechanisms of this animal to its desert biotope.

DecoFungi: a web application for automatic characterisation of dye decolorisation in fungal strains

BackgroundFungi have diverse biotechnological applications in, among others, agriculture, bioenergy generation, or remediation of polluted soil and water. In this context, culture media based on color change in response to degradation of dyes are particularly relevant; but measuring dye decolorisation of fungal strains mainly relies on a visual and semiquantitative classification of color intensity changes. Such a classification is a subjective, time-consuming and difficult to reproduce process.ResultsDecoFungi is the first, at least up to the best of our knowledge, application to automatically characterise dye decolorisation level of fungal strains from images of inoculated plates. In order to deal with this task, DecoFungi employs a deep-learning model, accessible through a user-friendly web interface, with an accuracy of 96.5%.ConclusionsDecoFungi is an easy to use system for characterising dye decolorisation level of fungal strains from images of inoculated plates.

Color stability of esthetic coatings applied to nickel-titanium archwires

Abstract Introduction Color stability is an important feature to be considered when using esthetic coated archwires. Objective To evaluate color changes on the surface of esthetic nickel-titanium archwires coated with Teflon (Ortho Organizers, USA) or epoxy resin (Tecnident, Brazil) after immersion in staining solution. Material and method Twelve 20-mm-long wire segments were used for each type of coating, which were mounted as two test specimens with a width of 7 mm each. The buccal surface of the archwires was evaluated for fluorescence and color measurements both at baseline and after immersion in a staining solution for 21 days using the VITA Easyshade® Compact spectrophotometer (Model DEASYC220). Differences in total color change according to coating type were compared using an independent samples t-test (p<0.05). The surface characteristics of as-received coated archwires were assessed using scanning electron microscopy. Result Color changes were observed on the esthetic coatings, with a significant difference between the two brands analyzed. Surface analysis revealed flaws such as wear, pitting, elevations, lack of material, granulation, grooves, cracks, and lack of standardization in the coating process in all as-received archwires, but flaws were less evident in epoxy-resin coatings. Conclusion The two esthetic coatings did not show color stability, but Teflon coatings showed a more intense color change than epoxy-resin coatings.

Boric Acid-Based Dual Modulation Photoluminescent Glucose Sensor Using Thioglycolic Acid-Capped CdTe Quantum Dots

Most luminescent glucose sensors based on the interaction of glucose with organic boric acids or borates. Herein, a new luminescent glucose sensor is designed using thioglycolic acid-capped CdTe quantum dots in the presence of cheap inorganic boric acid. Both peak position and intensities change upon the addition of glucose because of the interaction of boric acid with glucose and thioglycolic acid-capped CdTe quantum dots, which enables glucose detection by either color change or intensity change. The luminescent intensities change linearly with glucose concentrations in the ranges from 0.03 to 1 mM and 1–25 mM with a detection limit of 10 µM (S/N = 3). Moreover, glucose concentrations can be conveniently detected by color change in the range from 1 mM–25 mM. It displays a highly selective response to glucose over other interfering but biologically important saccharides, amino acids, and common ions. A thioglycolic acid-capped CdTe QD-based sensor can detect glucose with wide linear range by change in intensity or color in the presence of cheap inorganic boric acid.

Chemical Tongues and Noses Based upon Conjugated Polymers

We report the uses of conjugated polymers in multisensory applications and in chemical and optoelectronic tongues. We look at the potential of single polymers to discriminate multiple analytes and into small libraries of conjugated polymers that represent sensors. These small libraries combine several barely selective, promiscuous sensor elements and react with the analytes in a fairly non-selective fashion by change of color, emission wavelength, or emission intensity. In such optoelectronic noses and tongues, response of a single element is not specific or particularly useful at all, but the response pattern after the combination of several sensor elements is often specific for an analyte and allows discrimination and identification without any problem. These types of tongues and noses are well suited for quality control of foodstuff, beverages, and biological species such as proteins or cells. The discriminative process is often not well understood but it is powerful, particularly if the obtained data are analyzed by sophisticated statistical methods, i.e., linear discriminant analysis and/or principal component analysis. This added layer of analysis extracts the hidden information/patterns out of the data and allows visualization of the results.