Blue Research Articles

Preparation and Phytochemical Analysis of Polyherbal Tea Bag

Abstract: Herb blooms, leaves, seeds, roots, or dried fruit that aren't from the Camellia sinensis tea plant are referred to as herbal tea. Lemongrass, cinnamon, hibiscus, and butterfly pea (Clitoria ternatea) are a few plants that can be used to make herbal teas. The butterfly pea is traditionally used as a culinary coloring to give food its blue color and as an eye medication, brain boosting. As antioxidants, antibacterial, anti-inflammatory, antidiabetic, anti-cancer, and immunomodulatory agents, butterfly pea and hibiscus are beneficial and reduce blood pressure. In order to improve the quality of the herbal tea, it is necessary to dry the tea utilizing sunshine throughout the producing process. Organoleptic tests are used to conduct the analysis (color, taste, and scent).

Identification of the anthocyanin profile from butterfly pea (Clitoria ternatea L.) flowers under varying extraction conditions: Evaluating its potential as a natural blue food colorant and its application as a colorimetric indicator

This study aims to extract anthocyanins from BPF (Butterfly Pea Flower) to determine an effective solvent combination resulting in higher total anthocyanin content. Various solvent combinations were utilized to discern crucial characteristics of the obtained BPFE (Butterfly Pea Flower Extract). The BPFE from the optimal treatment was utilized as a pigment in colorimetric indicators, which were then evaluated for their initial response to seafood spoilage stored at room temperature for 24 h. The color change response of the colorimetric indicators employing BPFE pigment was compared with the pH and TVBN (Total Volatile base Nitrogen) values of the seafood initially and after 24 h. The highest total anthocyanin content was achieved with the combination of 96 % ethanol/1.5 N HCl (85:15, v/v) at 551.06 mg/L, followed by the combination of 96 % ethanol/distilled water (70:30, v/v) with pH adjustment to 1 using 1.5 N HCl at 484.27 mg/L. Subsequent combinations, in decreasing order, were 96 % ethanol/1.5 N HCl (99:1, v/v), 96 % ethanol/distilled water (70:30, v/v), and lastly, 96 % ethanol/distilled water (30:70, v/v), with total anthocyanin content of 275.53 mg/L, 200.39 mg/L, and 125.24 mg/L, respectively. BPFE applied in colorimetric indicators demonstrated responsiveness to seafood spoilage through color changes, with tested spoilage indicators being pH and TVBN. The initial (first hour) pH and TVBN values for each tested seafood were 5.5 and 9.42 mg/100 g (Scylla serrata), 6.4 and 4.23 mg/100 g (Litopenaeus vannamei), 5.4 and 11.29 mg/100 g (Uroteuthis sibogae), and 6.5 and 10.26 mg/100 g (Restrelliger kanagurta). Meanwhile, the pH and TVBN values after 24-h storage at room temperature became 7.9 and 57.01 mg/100 g, 7.4 and 76.65 mg/100 g, 7.5 and 216.44 mg/100 g, and 7.8 and 51.86 mg/100 g, respectively. The conclusion drawn is that the extraction of BPFE is more efficient when utilizing acidified ethanol solvent, and the resulting BPFE holds promise as a reliable pH indicator.

The Effect Of Substituting Butterfly Pea Extract As A Natural Dye In Mochi Production

Mochi is a traditional Japanese food made from glutinous rice flour with a sweet taste and a distinctive soft texture that turns chewy when eaten. Mochi is typically round in shape, filled with peanut paste, and coated with roasted cornstarch. In Indonesia, mochi has various variations, one of which involves modifying the mochi's outer layer by adding food coloring to the dough. As time progresses, people have become more aware of the negative effects of synthetic ingredients, leading consumers to shift towards using natural food colorings. Butterfly pea flowers are one alternative source of natural food coloring. These flowers contain anthocyanin compounds that can produce a blue color. The use of butterfly pea flowers does not affect the taste of food products since it only contains anthocyanins. The purpose of this study is to analyze the quality of mochi with the addition of butterfly pea flower extract. The research method employed is a pure experiment, using a Completely Randomized Design (CRD) with three repetitions. Data was collected by surveying a limited group of panelists, who are Family Welfare Science lecturers with a concentration in Culinary Arts at the Faculty of Tourism and Hospitality, Universitas Negeri Padang. Data was analyzed using Analysis of Variance (ANOVA), and if F-value > F-table, then the Duncan test was conducted. The research results indicate a significant effect on color quality. However, the shape (neat and uniform), aroma, texture, and taste did not show a significant effect. The highest overall scores were as follows: neat shape 3.11 (X1), uniform shape 3.11 (X1), blue color 3.44 (X1), pleasant aroma 3.33 (X0), chewy texture 3.67 (X1), and sweet taste 3.33 (X1). The best result in this study was treatment (X1) with a 50% substitution of butterfly pea flower extract.

Not all apparently gynandromorphic butterflies are gynandrous: The case of Polyommatus icarus and its relatives (Lepidoptera: Lycaenidae)

Beside the more than two thousand normal specimens of Polyommatus icarus (Rottemburg, 1775) yielded by rearing experiments, there was one perfectly bilateral dichromatic individual first considered to be gynandrous. On the basis of analysing genitalia traits, wing surface covering scale micromorphology, and the spectral characteristics of the blue colour generated by the cover scales, the gender of the specimen has been identified as female. This exemplar was investigated in comparison with gynandrous specimens from the collections of the Hungarian Natural History Museum exhibiting various degrees of intermixing of blue and brown coloration. Focus stacking microscopy for detailed scale morphology and UV–visible reflectance spectroscopy was used for the characterization of the optical properties. Inspecting literature references and the Lycaenidae collection of the museum, further examples have been found for female bilateral dichromatism in the closely related polyommatine lycaenid species Lysandra bellargus (Rottemburg, 1775) and Lysandra coridon (Poda, 1761) what suggests that polyommatine female dichromaticity may be displayed by the manner of bilaterality and mosaicism, phenomena hitherto solely connected to gynandromorphy.

Dynamic range issues and image information content when visualizing seismic data

The purpose of this review is to discuss the problem of seismic data visualization in relation to human vision capabilities based on the seismic signal dynamic range assessment. The ways of increasing the information content and efficiency of visualization methods in terms of increasing their resolution are considered. The conducted analysis has shown that the dynamic range of seismic recordings exceeds the capabilities of the human eye by 2–3 orders of magnitude and the capabilities of technical visualization means by 4–5 orders of magnitude. Color vision models are considered on example of the most versatile hardware additive RGB color model. The model was chosen based on the idea of the human vision system as a set of photosensitive cones that register red, green and blue colors and the human brain, which processes and forms a color image in one’s consciousness. The relationships between monochrome and color images perceived by the human eye based on several types of sensitive receptors have been established. It is concluded that the use of a color image significantly expands information capabilities. Thus, 8 grey steps are enough for the monochrome method of information output, whereas the use of color devices allows to increase the number of steps up to 14. The methodology for solving this problem consists in the application of new technologies based on the use of large-scale and three-dimensional images providing a significant increase in the values of luminous flux, resolution and contrast based on the expansion of the dynamic range taking into consideration the limits of human vision.

A water-based ultrasound-assisted extraction system to obtain natural blue colorant from Genipap (Genipa americana L.)

This study aimed to optimize the extraction of a blue colorant using ultrasound-assisted technology employing water as the solvent from genipap, an Amazon fruit. Process conditions were optimized by multiresponse analysis through the antioxidant activity by the ferric reducing antioxidant potential (FRAP) assay, the total phenolic content, and the b* and C* color parameters. The optimized conditions of 70 °C, 325 W, solid: solvent ratio of 1:40 (m/v), and time of 10 min were validated externally at a level of 90 % confidence. The composition of aqueous blue extract obtained under the greatest conditions was evaluated by ultra-performance liquid chromatography (UPLC). Besides, in vitro bioactivities such as digestive enzymatic inhibitions assays, and antiproliferative activity through human cells assays were evaluated. Genipin, geniposide, and other ten iridoids were identified in the aqueous blue extract. The natural colorant obtained presented the capacity of inhibiting enzymes involved in lipid and glucose digestion, suggesting a potential control of obesity and glucose levels in blood without showing cytotoxicity. Therefore, this study presented, for the first time, the optimal operational conditions to obtain a natural blue colorant from genipap in a green approach with interesting biological properties for the food and pharmaceutical industries.

‘BLUES’ procedure for assessing the blue level of the sclera in Osteogenesis Imperfecta

PurposeBlue sclera is a characteristic and common clinical sign of Osteogenesis Imperfecta (OI). However, there is currently no widely accepted, objective method for assessing and grading blue sclera in individuals with OI.To address this medical need, this study is aimed to design and validate a new method called ‘BLUES’ (BLUe Eye Sclera) to objectively identify and quantify the blue color in the sclera of patients affected by OI.MethodsSixty-two patients affected by OI and 35 healthy controls were enrolled in the present prospective study, for a total of 194 eyes analyzed.In the 'BLUES' procedure, eye images from patients with OI and control subjects were analyzed to assess and grade the blue level of the sclera using Adobe Photoshop Software. The validation process then involved comparing the results obtained with the ‘BLUES’ procedure to the judgement of experienced ophthalmologists (JEO).A receiver-operating characteristic (ROC) curve analysis was used to examine the overall discriminatory power. The sensitivity and specificity levels and the Cohen's Kappa (K) indexes of ‘BLUES’ and ‘JEO’ were estimated versus the standard OI diagnosis. The K indexes of ‘BLUES’ versus ‘JEO’ were also evaluated.ResultsThe optimal cut-off point of the scleral blue peak was calculated at 17%. Our findings demonstrated a sensitivity of 89% (CI95%: 0.835–0.945) and specificity of 87% (CI95%: 0.791–0.949) for the ‘BLUES’ procedure with an agreement versus the diagnosis of OI of 0.747. In comparison, the sensitivity and specificity of ‘JEO’ ranged from 89 to 94% and 77% to 100%, respectively, with an agreement ranging from 0.663 to 0.871 with the diagnosis of OI. The agreement between ‘BLUES ‘and ‘JEO’ evaluations ranged from 0.613 to 0.734.ConclusionsOur findings demonstrated an 89% sensitivity and an impressive 87% specificity of our method to analyze the blue sclera in OI. The results indicated high agreement with disease diagnosis and were consistent with evaluations by experienced ophthalmologists. The ‘BLUES’ procedure appears to be a simple, reliable and objective method for effectively identify and quantify the blue color of the sclera in OI.

Incidence of microplastics in Indian anchovy Stolephorus indicus from Tuticorin, Southeast coast of India

In the present study, the occurrence of microplastics (MPs) in the gut, gill, and muscle of edible fish Stolephorus indicus sampled from Tuticorin coastal regions of Tamilnadu, India was investigated. We recorded a total of 689 MPs which includes 510 and 179 MPs from males and females respectively. The total abundance of MPs was significantly (P < 0.05) higher in the gut followed by gills and muscle. The sex-wise distribution of average MPs showed high in the females' gut and compared to that in males. Further, the length wise distribution of MPs was higher in the muscle in both male and female fish, followed by other organs. The predominance of MPs in tissues were transparent and blue colour with fibers and fragments in both males and females. Besides, polyethylene terephthalate and nylon were evidenced by the Fourier-transform infrared spectroscopy spectrum in all organs of fishes.

Probing the Stellar Populations and Star Formation History of Early-type Galaxies at 0 < z < 1.1 in the Rest-frame Ultraviolet

We measure the evolution of the rest-frame near-ultraviolet (NUV)−V colors for early-type galaxies in clusters at 0 < z < 1.1 using data from the Hyper Suprime-Cam Subaru Strategic Program, CFHT Large Area U-band Deep Survey, and local Sloan Digital Sky Survey clusters observed with Galaxy Evolution Explorer. Our results show that there is an excess in the ultraviolet spectrum in most quiescent galaxies (compared to the expectations from models fitting their optical/infrared colors and spectra) below z ∼ 0.6, beyond which the excess UV emission fades rapidly. This evolution of the UV color is only consistent with the presence of a highly evolved, hot horizontal branch subpopulation in these galaxies (among the majority of cool and optically bright stars), comprising on average 10% of the total stellar mass and forming at z > 3. The blue UV colors of early-type galaxies at low–intermediate redshifts are likely driven by this subpopulation being enriched in helium up to ∼44%. At z > 0.8 (when the extra UV component has not yet appeared) the data allow us to constrain the star formation histories of galaxies by fitting models to the evolution of their UV colors: we find that the epoch at which the stellar populations formed lies in the range 3 < z form < 10 (corresponding to 0.5–2.2 Gyr after the Big Bang) with a star formation e-folding timescale of τ = 0.35–0.7 Gyr, suggesting that these galaxies formed the majority of stars at very high redshift, with a brief yet intense burst of star formation activity. The star formation history and chemical evolution of early-type galaxies resemble those of globular clusters, albeit on much larger scales.

Blaze-angle led dark-blue iridescence and superhydrophobicity features of non-morpho Euploea midamus butterfly wing scale

We report on backlit iridescent blue structural coloration as well as superhydrophobicity in a non-morpho butterfly of Euploea midamus (blue-spotted crow) belonging to the Lepidoptera order. Select forewing and hindwing parts were characterized by employing optical microscopy, field emission electron microscopy, UV–vis-NIR spectrophotometry, and an advanced contact angle meter. As substantiated from variable incident angle reflectance spectra and chromaticity plots, the apparent visual effect is most pronounced in the forewing case and at an incident angle of 30–40°, with reflectance peak maxima positioned at ~ 412 nm and 478 nm. Additionally, the forewing scale of this butterfly acts as an anti-reflection filter (< 460 nm) for p-polarized light, showing greater polarization anisotropy in the lower wavelength region. Numerical simulationand microstructure-based analytical calculations with blaze angle grating effects have been considered to elucidate the observed dark-blue iridescence at large. Moreover, both the forewing and hindwing of the butterfly exhibit the ‘lotus effect’, with a contact angle as high as of ~ 150°, low contact angle hysteresis (16° and 13°) as well as low roll-off angles (10° and 7°) to favor self-cleaning action. Theoretical calculations attributing to dual roughnesses would encompass micro-textured and nanoscale asperities within the wing scale interface. The scope of the bifunctional features including optical and dewetting responses in natural systems would provide valuable insights and clues for biomimetics, particularly in nanophotonic and nanocoating applications.

Siderophore-producing bacteria from Spitsbergen soils—novel agents assisted in bioremediation of the metal-polluted soils

Siderophores are molecules that exhibit a high specificity for iron (Fe), and their synthesis is induced by a deficiency of bioavailable Fe. Complexes of Fe-siderophore are formed extracellularly and diffuse through porins across membranes into bacterial cells. Siderophores can bind heavy metals facilitating their influx into cells via the same mechanism. The aim of the studies was to determine the ability of siderophore-producing bacteria isolated from soils in the north-west part of Wedel Jarlsberg Land (Spitsbergen) to chelate non-Fe metals (Al, Cd, Co, Cu, Hg, Mn, Sn, and Zn). Specially modified blue agar plates were used, where Fe was substituted by Al, Cd, Co, Cu, Hg, Mn, Sn, or Zn in metal-chrome azurol S (CAS) complex, which retained the blue color. It has been proven that 31 out of 33 strains were capable of producing siderophores that bind to Fe, as well as other metals. Siderophores from Pantoea sp. 24 bound only Fe and Zn, and O. anthropi 55 did not produce any siderophores in pure culture. The average efficiency of Cd, Co, Cu, Mn, Sn, and Zn chelation was either comparable or higher than that of Fe, while Al and Hg showed significantly lower efficiency. Siderophores produced by S. maltophilia 54, P. luteola 27, P. luteola 46, and P. putida 49 exhibited the highest non-Fe metal chelation activity. It can be concluded that the siderophores of these bacteria may constitute an integral part of the metal bioleaching preparation, and this fact will be the subject of further research.Graphical

Antioxidant and Anti-inflammatory activity of the Terpenoidal fraction of Ethanolic extract of Byttneria herbacea

The goal of this study was to identify the bioactive principle of the plant Byttneria herbacea (Malvaceae) which has a wide range of traditional therapeutic uses.Column chromatography was used to separate the ethanolic extract of aerial parts of the plant with mobile phase Chloroform: Methanol (5:5). The fraction with Rf 0.62 on TLC with mobile phase Toluene:Ethyl acetate (85:15) imparting bluish color under UV 254 nm was giving the test of Terpenoids. The same fraction was assessed for Antioxidant and Anti-inflammatory activity.Antioxidant activity was performed by measuring the decolourizing activity followed by capturing the unpaired electron from the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and compared it with the standard anti-oxidant Gallic acid. To test anti-inflammatory activity in an experimental model of acute inflammation, the carrageenan-induced in rat paw edema method was employed.The antioxidant and the anti-inflammatory activities of the Terpenoid fraction were found to be satisfactory.

Simple Measurement of Conductivity of Colored Acrylic Sheets

In many applications, colored acrylic sheets require information on thermal conductivity values. However, thermal conductivity data has not been found in the literature and research publications, especially colored acrylic sheets. The purpose of this study was to investigate the heat conductivity value of colored acrylic sheets including transparent, cloudy, white, black, green and blue colors found in the market. This research was done with the experimental method of measuring the thermal conductivity of colored acrylic in a closed room four rectangles 80 cm x 40 cm x 40cm of 9 mm plywood coated with black paper and divided into two compartments and test material 40 cm x 40 cm x 0.3cm as patisi room. The heat source used is a 75watt incandescent lamp placed on one side of the room. Acrylic thermal conductivity is calculated based on temperature data at each measurement point reaching a steady state which is obtained at the 30th minute and taking into account the convection heat and air radiation in the test chamber. The results showed that pigment additives greatly affect the thermal conductivity value of acrylic and its value is lower than the conductivity value of acrylic colorless sheet transfaran.

Insights into the mechanism of color formation of the freshwater prawn (Macrobrachium rosenbergii) revealed by de novo assembly transcriptome analysis

Body color is an important visual indicator of crustacean quality and plays a major role in consumer acceptability, perceived quality, and the market price of crustaceans. The freshwater prawn (Macrobrachium rosenbergii) has two distinct phenotypic variations, characterized by dark blue and light yellow body colors. However, the underlying mechanisms regulating the body color of M. rosenbergii remain unclear. In this study, the composition of shell color parameters and pigment cells of raw and cooked dark blue and light yellow M. rosenbergii was investigated and the mechanisms associated with body color were elucidated by transcriptome analysis. The results showed significant differences in the raw shells of the dark blue and light yellow M. rosenbergii (L: 26.20 ± 0.53 vs. 29.25 ± 0.45; a: −0.88 ± 0.19 vs. 0.35 ± 0.18; b: 1.73 ± 0.20 vs. 3.46 ± 0.37; dE: 70.33 ± 0.53 vs. 67.34 ± 0.45, respectively, p = 0.000) as well as the cooked shells (L: 58.14 ± 0.81 vs. 55.78 ± 0.55; a: 19.30 ± 0.56 vs. 16.42 ± 0.40; b: 23.60 ± 0.66 vs. 20.30 ± 0.40, respectively, p < 0.05). Transcriptome differential gene analysis obtained 39.02 Gb of raw data and 158,026 unigenes. Comprehensive searches of the SwissProt, Nr, KEGG, Pfam, and KOG databases resulted in successful annotations of 23,902 (33 %), 40,436 (25.59 %), 32,015 (20.26 %), 26,139 (16.54 %), and 22,155 (14.02 %) proteins, respectively. By KEGG pathway analysis, numerous differentially expressed genes were related to pigmentation-related pathways (MAPK signaling pathway, Wnt signaling pathway, melanin production, tyrosine metabolism, and cell-cell communication process). Candidate DEGs that may be involved in body color included apolipoprotein D, crustacyanin, cytochrome P450, and tyrosinase, as verified by quantitative real-time PCR. The results of this study provide useful references to further elucidate the molecular mechanisms of color formation of M. rosenbergii and other crustaceans.

Empirical BRDF model for goniochromatic materials and soft proofing with reflective inks.

The commonly used analytic bidirectional reflectance distribution functions (BRDFs) do not model goniochromatism, that is, angle-dependent material color. The material color is usually defined by a diffuse reflectance spectrum or RGB vector and a specular part based on a spectral complex index of refraction. Extension of the commonly used BRDFs based on wave theory can help model goniochromatism, but this comes at the cost of significant added model complexity. We measured the goniochromatism of structual color pigments used for additive color printing and found that we can fit the observed spectral angular dependence of the bidirectional reflectance using a simple modification of the standard microfacet BRDF model. All we need to describe the goniochromatism is an empirically-based spectral parameter, which we use in our model together with a specular reflectance spectrum instead of the spectral complex index of refraction. We demonstrate the ability of our model to fit the measured reflectance of red, green, and blue commercial structural color pigments. Our BRDF model enables straightforward implementation of a shader for interactive preview of 3D objects with printed spatially and angularly varying texture.

Application of machine learning and multivariate approaches for assessing microplastic pollution and its associated risks in the urban outdoor environment of Bangladesh

Microplastics (MPs) are an emerging global concern due to severe toxicological risks for ecosystems and public health. Therefore, this is the first study in Bangladesh to assess MP pollution and its associated risks for ecosystems and human health in the outdoor urban environment using machine learning and multivariate approaches. The occurrences of MPs in the urban road dust were 52.76 ± 20.24 particles/g with high diversity, where fiber shape (77%), 0.1–0.5 mm size MPs (75%), blue color (26%), and low-density polyethylene (24%) polymer was the dominating MPs category. Pollution load index value (1.28–4.42), showed severe pollution by MPs. Additionally, the contamination factor (1.00–5.02), and Nemerow pollution index (1.38–5.02), indicate moderate to severe MP pollution. The identified polymers based on calculated potential ecological risk (2248.52 ± 1792.79) and polymer hazard index (814.04 ± 346.15) showed very high and high risks, respectively. The occurrences of MPs could effectively be predicted by random forest, and support random vector machine, where EC, salinity, pH, OC, and texture classes were the influencing parameters. Considering the human health aspect, children and adults could be acutely exposed to 19259.68 and 5777.90 MP particles/ year via oral ingestion. Monte-Carlo-based polymers associated cancer risk assessment results indicate moderate risk and high risk for adults and children, respectively, where children were more vulnerable than adults for MP pollution risks. Overall assessment mentioned that Dhaka was the most polluted division among the other divisions.

The Primitive Exponent Set of a Class of Representative Twocolored Digraph in Graph Theory

Graph is simple and intuitive. It can be used to solve many problems in computer science. For a kind of representativedigraph, the edges (arcs) of the digraph are colored with red and blue colors. The range of the primitive exponent are discussed indifferent cases, and the extremal two-colored digraphs are found by coloring all arcs with two colors. Finally, the primitive exponentset is given. The results can provide a reference for the study of primitive exponent of three-colored digraph and the application ofgraph coloring in computer science, such as communication network and coding cache.

Near-infrared reflective Mg0.5Co0.5-xMnxAl2O4 black pigment synthesized by spray pyrolysis: Optimization of composition and calcination temperature

Co/Mn co-substituted MgAl2O4 pigments were spray pyrolysis, and their crystal structure and optical properties were characterized with changing the Co/Mn ratio and synthesis temperature. Regardless of the Co/Mn ratio, the resulting pigments showed spinel structured MgAl2O4 phase without any impurity phase. The synthesized Mg0.5Co0.5Al2O4 and Mg0.5Mn0.5Al2O4 showed a dark blue and brown color due to the visible light absorption by the 4A2(F) → 4T1(P) transition of Co2+ and the d-d transition of Mn2+, respectively. The black colored pigment was achieved by simultaneous substituting Co2+ and Mn2+ in the Mg2+ tetrahedral site in MgAl2O4. The optical band gap of the Mg0.5Co0.5-xMnxAl2O4 pigment decreased linearly from 3.08 eV (x = 0) to 2.46 eV (x = 0.4) as the Mn2+ content increased. As a result, Mg0.5Co0.1Mn0.4Al2O4 uniformly absorbed the entire visible light and had a black color (L* = 28.10, C* = 1.68). In terms of obtaining high near-infrared reflectance and good blackness, the optimal calcination temperature of Mg0.5Co0.1Mn0.4Al2O4 was determined to be 900 °C. The optimized Mg0.5Co0.1Mn0.4Al2O4 black pigment had a good LiDAR reflectance (38 % at 905 nm) and excellent chemical stability, and showed improved heat shielding performance compared to carbon black using in black vehicles.

A Boron, Nitrogen, and Oxygen Doped π-Extended Helical Pure Blue Multiresonant Thermally Activated Delayed Fluorescent Emitter for Organic Light Emitting Diodes That Shows Fast kRISC Without the Use of Heavy Atoms.

Narrowband emissive multiresonant thermally activated delayed fluorescence (MR-TADF) emitters are a promising solution to achieve the current industry-targeted color standard, Rec. BT.2020-2, for blue color without using optical filters, aiming for high-efficiency organic light-emitting diodes (OLEDs). However, their long triplet lifetimes, largely affected by their slow reverse intersystem crossing rates, adversely affect device stability. In this study, a helical MR-TADF emitter (f-DOABNA) is designed and synthesized. Owing to its π-delocalized structure, f-DOABNA possesses a small singlet-triplet gap, ΔEST, and displays simultaneously an exceptionally faster reverse intersystem crossing rate constant, kRISC, of up to 2 × 106 s-1 and a very high photoluminescence quantum yield, ΦPL, of over 90% in both solution and doped films. The OLED with f-DOABNA as the emitter achieved a narrow deep-blue emission at 445nm (full width at half-maximum of 24nm) associated with Commission Internationale de l'Éclairage (CIE) coordinates of (0.150, 0.041), and showed a high maximum external quantum efficiency, EQEmax, of ≈20%.

Chemical and biological study of flavonoid-related plant pigment: current findings and beyond.

Flavonoids are polyphenolic plant constituents. Anthocyanins are flavonoid pigments found in higher plants that show a wide variety of colors ranging from red through purple to blue. The blue color of the flowers is mostly attributed to anthocyanins. However, only a few types of anthocyanidin, chromophore of anthocyanin, exist in nature, and the extracted pigments are unstable with the color fading away. Therefore, the wide range and stable nature of colors in flowers have remained a mystery for more than a century. The mechanism underlying anthocyanin-induced flower coloration was studied using an interdisciplinary method involving chemistry and biology. Furthermore, the chemical studies on flavonoid pigments in various edible plants, synthetic and biosynthetic studies on anthocyanins were conducted. The results of these studies have been outlined in this review.