Deep Red Color Research Articles

Full‐Color and High‐Resolution Femtosecond Laser Patterning of Perovskite Quantum Dots in Polyacrylonitrile Matrix

AbstractLaser patterning of perovskite quantum dots (PQDs) in polymer matrix enables in situ synthesis, easy integration, and much improved long‐term stability, holding great promises for varieties of photonics, and optoelectronics applications. Although multi‐color PQD patterns have been demonstrated through tuning the halide stoichiometry, it remains significantly challenging to achieve full‐color patterns due to the slow and spontaneous crystallization of the chlorinated perovskite precursor at room temperature. Herein, polyacrylonitrile (PAN) is introduced to serve as the matrix material, the excess cyano groups of which would coordinate with dissociative cesium and lead cations in the precursor film, leading to the suppression of the unprompted crystallization process. Taking advantage of the nonthermal and contactless ultrafast femtosecond laser, full‐color PQDs are in situ fabricated by tuning the halide stoichiometry in the PAN matrix, with the emission wavelength in the range of 425–685 nm, spanning from deep blue to deep red color, and a sub‐diffraction feature size of ≈400 nm. The approach allows ultrafine and programmable fabrication of full‐color PQD arrays and arbitrary patterns with high resolution and stability. This facile, efficient, and reliable technique believed to offer a novel pathway for precise manufacturing of various photonic or optoelectronic devices based on patterned PQDs.

Understanding Europium and Terbium Speciation and Ion Pairing in Carbonate Complexes Using Advanced Spectroscopy Techniques

Lanthanide (Ln) elements are critical materials that are typically extracted/mined together. Their separation by solvent extraction from acidic media is well known; however, there are few studies in basic media with carbonate anions. We investigated the complexation of Eu(III) and Tb(III) carbonates as solids and solutions in alkaline K2CO3, wherein we sought to access a Tb(IV) carbonate complex through ozonolysis. L3‐edge XANES of Eu and Tb carbonate solids, colorless solutions, and a red‐hued Tb solution (obtained by ozonolysis) all showed Ln(III) cations. The absence of evidence for a Tb(IV) complex was confirmed through XAS and EPR analyses, despite the solution exhibiting a deep red color. For solids and solutions, EXAFS results indicate molecular Ln(III)‐carbonato anions. In terms of the Eu(III) carbonate coordination number, the coordination does not change upon dissolution of the solid sample. Furthermore, EXAFS for the solutions revealed evidence for the association of potassium cations with the Ln(III)‐carbonato anions. This direct observation of contact ion pairing by EXAFS at room temperature is rare. The insights into Ln(III) carbonate complexation and solution speciation afforded by XANES‐EXAFS, FT‐IR, and EPR provides perspectives that serve as benchmarks for future computational and experimental efforts focused on caustic‐side solvent extraction of Ln(III) ions.

Facile Preparation of Gold Nanoparticles Silica Composite Film Embedded in Anodized Aluminium Oxide-Glass Substrate

Thin film based on gold nanoparticles or AuNPs is typically used as catalyst in the industrial processes due to their high stability and good reusability. In this work, a thin AuNPs-silica composite film was fabricated firstly from sol-gel method by mixing gold pyrazolate complex to a medium comprised of ethanol, deionized water, and hydrochloric acid followed by addition of tetrabutyl orthosilicate as silica source. Next, 70 microliters of the sol-gel solution were spin-coated on several type of substrates such as glass, anodized aluminium oxide or AAO, and combination of both to yield gold complex-silica composite film. It was found that gold complex-silica composite film fabricated on combination of both AAO-glass substrate gave the best quality based on its surface thickness, layer uniformity and film brittleness. Later, the film was selected and subjected to thermal hydrogen reduction at 210 degrees Celsius for 2 hours to facilitate the formation of gold nanoparticles to give AuNPs-silica in AAO-glass film. Before the heat treatment, the light-brownish colour of the original gold complex-silica in AAO-glass film in daylight will appear as a pinkish red film under UV light, suggesting the interaction between gold atoms and supported by its luminescence spectrum at 692 nm. Upon heat treatment, the resulting AuNPs-silica in AAO-glass film gave a deep-red colour indicating the successful formation of AuNPs. The presence of AuNPs in the film was further confirmed based on the absorption peak at 545 nm, X-ray diffraction pattern at 38.20 degrees for d111 plane in wide-angle region, transmission electron microscopy images showing a small and sphere shape particles as well as its elemental composition in energy dispersive X-ray analysis. Moreover, scanning electron microscope images also suggested that the AAO pores is fully filled with the composite and is in accordance with its surface roughness study via atomic force microscopy analysis.

Contribution of extractives to the bark color of Caesalpinia sappan

The purpose of this study was to investigate the contribution of Caesalpinia sappan (sappan wood) bark extractives by analyzing color change of the bark after extraction and the color of the extracts with several color measurement methods. Successive extraction was performed with n-hexane, ethyl acetate, methanol, and hot water. Color change of the bark was measured using CIELab color system and the extracts were analyzed with Ultraviolet-Visible Spectrophotometer, total phenolic content (TPC), and Gas Chromatography Mass Spectrometry (GC-MS). The results showed that the highest change on the bark color after methanol extraction with the Δa* and Δb* values of -2,53 ± 0,60 and -3,64 ± 1,20 respectively. Also, methanol extract showed the highest total phenolic content (860,24 ± 30,19 mg GAE/g). In addition, the Ultraviolet-Visible is analysis showed a peak at 478 nm in the hot-water soluble extract and two peaks in the methanol soluble extract at 396 nm and 478 nm. Hydroquinone was detected as one of the major compounds by Gas Chromatography Mass Spectrometry in the methanol soluble extract. It was suggested that the color of Caesalpinia sappan (sappan wood) bark as well as the deep red coloration of its extract might be contributed by multiple phenolic compounds contained in the methanol extract with hydroquinone as its precursor. Therefore, it is also a potential source for coloring matter.

Comparative Response of Arbuscular Mycorrhizal Fungi versus Endophytic Fungi in Tangor Citrus: Photosynthetic Efficiency and P-Acquisition Traits

Citrus plants are prone to phosphorus (P) deficiency, especially in acidic soil, making them more dependent on root-associated endophytic fungi for growth and development. Beni-Madonna, a hybrid of Citrus nanko × C. amakusa, is a citrus known as “tangor” that is highly popular in China and other parts of the world due to its deep red color and jelly-like flesh. In this study, the inoculation response to two arbuscular mycorrhizal fungi (Diversispora versiformis, Dv; Funneliformis mosseae, Fm) and an endophytic fungus (Serendipita indica, Si) with regard to the growth, leaf gas exchange, light energy efficiency, P levels, acid phosphatase activity, and expression of the purple acid phosphatase (PAP) and phosphate transporter (PT) genes through a potted experiment using Beni-Madonna (tangor) citrus plants grafted on trifoliate orange (Poncirus trifoliata) was studied. Two years following inoculation, the root fungal colonization rates of inoculated plants were significantly increased, accompanied by an increase in plant height and stem diameter, with Si presenting the best effect. Fungal inoculations also significantly increased the leaf chlorophyll index, nitrogen-balance index, photosynthesis rate, stomatal conductance, transpiration rate, photosynthetic efficiency, and quantum yield of PSII, while it reduced photoinhibition and heat dissipation, with Si having the best effect on light energy efficiency. Si significantly increased leaf and root P levels, as well as root CsPAP1‒3, CsPT2, CsPT3, and CsPT7 expression and soil acid phosphatase activity; Fm in mycorrhizal fungi significantly increased leaf and root P levels, as well as root CsPT1 and CsPT7 expression and root/soil acid phosphatase activity. These observations suggested an advantage of Si over the other two AMF in terms of improved plant growth and P acquisition, while Fm displayed prominent effects on increased photosynthetic efficiency.

Using an image processing technique, correlating the lycopene and moisture content in dried tomatoes

Food staples like tomatoes (Lycopersicon esculentum) are rich in lycopene, which provides ripe tomatoes their deep red colour and is thought to provide health benefits. The consumer's acceptance of the food item depends on the tomatoes' appearance and colour. The traditional methods for determining colour, such as the Dr. Lange and Minolta colorimeters, which worked on surface characteristics, that renders the measurements extremely anomalous & makes it more challenging to conduct a global examination of the food's surface. In order to evaluate tomatoes' colour as they dry and to associate that hue to lycopene and moisture content of tomatoes, this study provides a computer vision system-based technique. Additionally, the colour was determined using a Hunter lab colorimeter, and the results were connected with the moisture and lycopene levels. L*a*b* was chosen as the colour space because of the consistent distribution of hues and how closely it resembles how people perceive colour. According to the findings, drying caused a considerable drop in the L*a*b* values as measured by Hunter Lab and by image analysis. The regression of moisture content generated a very strong association with the moisture content trial data. Lycopene and the results of the experiments on its content correlated well.

Cascading Energy Transfer for Highly Efficient Deep-Red OLED Emission with Cyclometalated [3+2+1] Iridium Complexes.

The promising cyclometalated iridium (III) complexes have been proved to possess great potential in vacuum-deposited organic light-emitting diodes (OLEDs) applications for full-color displays and white solid-state lighting sources. Herein, based on the unique bidentate ligand of dibenzo[a,c]phenazine (dbpz) group with strong conjugated effect of aromatic rings for red emission, four novel [3+2+1] coordinated iridium (III) emissive materials have been rationally designed and synthesized. The monodentate ligands of -CN and -OCN have been effectively employed to tune the deep-red emission of 628-675nm with high photoluminescence quantum yields up to 98%. Moreover, all devices displayed deep-red color coordinates ranging from (0.675, 0.325) to (0.716, 0.284), which is close to the standard-red color coordinates of (0.708, 0.292), as recommended by International Telecommunication Union Radiocommunication (ITU-R) BT.2020. The device based on nBuIr(dbpz)CN with an exciplex cohost has exhibited maximum external quantum efficiencies of 20.7% and good stability. With nBuIr(dbpz)CN as an effective sensitizer, the nBuIr(dbpz)OCN based phosphorescent OLED devices have successfully demonstrated cascading energy transfer processes, contributing to pure red emission with maximum luminance as high as 6471cd m-2. Therefore, this work has been successfully demonstrated rational molecular design strategy of [3+2+1] iridium complexes to obtain highly efficient deep-red electrophosphorescent emission.

Uridine Diphosphate Glycosyltransferases (UGTs) Involved in the Carotenoid-Based Body Color Difference between Tetranychus cinnabarinus (Red) and Tetranychus urticae (Green).

It has long been disputed whether Tetranychus cinnabarinus and Tetranychus urticae belong to the same genus, with T. cinnabarinus regarded as a red form of T. urticae. However, it is unclear why T. urticae and T. cinnabarinus have different body colors. Since carotenoids are responsible for the color of many organisms, the carotenoid profiles of T. cinnabarinus and T. urticae were compared by HPLC. There was no difference in carotenoid type, but T. cinnabarinus contained significantly more neoxanthin, astaxanthin, α-carotene, β-carotene, and γ-carotene, which may contribute to the deep red color. The transcriptome sequencing of both species identified 4079 differentially expressed genes (DEGs), of which 12 were related to carotenoid metabolism. RNA interference (RNAi) experiments demonstrated that silencing seven of these DEGs resulted in the different accumulation of carotenoid compounds in T. cinnabarinus and T. urticae. In addition, the body of T. urticae turned yellow after two days of feeding with UGT double-stranded RNAs and β-UGT small interfering RNAs. In conclusion, differences in the carotenoid profiles of T. urticae and T. cinnabarinus may be responsible for the different body colors.

Molecular mechanism controlling anthocyanin composition and content in radish plants with different root colors

Radish (Raphanus sativus) roots exhibit various colors that reflect their anthocyanin compositions and contents. However, the details of the mechanism linking the expression of anthocyanin biosynthesis and their transcriptional regulators to anthocyanin composition in radish roots remained unknown. Here, we characterized the role of the anthocyanin biosynthetic enzyme flavonoid 3′-hydroxylase (RsF3′H), together with the R2R3 MYB transcription factor (TF) RsMYB1 and the basic helix-loop-helix (bHLH) TF TRANSPARENT TESTA 8 (RsTT8), in four radish plants with different root colors: white (W), deep red (DR), dark purple (DP), and dark greyish purple (DGP). The DR plant contained heterozygous for RsF3′H with low expression level and accumulated a large amount of pelargonidin, resulting in deep red color. While, the DP and DGP plants accumulated the cyanidin due to the higher expression level of functional RsF3′H. Notably, RsMYB1 and RsTT8 transcripts were abundant in all pigmented roots, but not in white roots. To investigate the differential expression of RsMYB1 and RsTT8, we compared the sequences of their promoter regions among the four radish plants, revealing variations in the numbers of cis-elements and in promoter architecture. Promoter activation assays demonstrated that variation in the RsMYB1 and RsTT8 promoters may contribute to the expression level of these genes, and RsMYB1 can activate its own expression as well as promote the RsTT8 expression. These results suggested that RsF3′H plays a vital role in anthocyanin composition and the expression level of both RsMYB1 and RsTT8 are crucial determinants for anthocyanin content in radish roots. Overall, these findings provide insight into the molecular basis of anthocyanin composition and level in radish roots.

Phytochemical and Agronomic Characterization of High-Flavonoid Lettuce Lines Grown under Field Conditions.

Flavonoids are antioxidant phytochemicals that confer a beneficial effect on human health. We have previously developed and characterized eight lettuce (Latuca sativa L.) lines that accumulated high levels of diverse flavonoids and their precursors in controlled environment conditions. Three Rutgers Scarlet lettuce (RSL) lines selected in tissue culture for deep-red color (RSL-NAR, RSL-NBR, RSL-NFR) accumulate anthocyanins and quercetin, three lines identified in a chemically mutagenized red lettuce population accumulate kaempferol (KfoA and KfoB) or naringenin chalcone (Nco), and two lines that were spontaneous green mutants derived from the red line RSL-NAR (GSL, GSL-DG) accumulate quercetin. These eight lines were field-grown in the Salinas Valley of California for four years together with seven control accessions of varying colors (light green, dark green, red, and dark red). At market maturity, a substantial variation in plant composition was observed, but the three RSL lines consistently accumulated high levels of cyanidin, GSL and GSL-DG accumulated the highest levels of quercetin, KfoA and KfoB accumulated kaempferol, and Nco amassed naringenin chalcone, confirming that these mutant lines produce high levels of beneficial phytochemicals under field conditions. Mutant lines and control accessions were also assessed for their biomass production (plant weight, height, and width), overall content of pigments (leaf chlorophyll and anthocyanins), resistance to diseases (downy mildew, lettuce drop, and Impatiens necrotic spot virus), postharvest quality of processed tissue (deterioration and enzymatic discoloration), and composition of 23 mineral elements. All but one mutant line had a fresh plant weight at harvest comparable to commercial leaf cultivars; only Nco plants were significantly (p < 0.05) smaller. Therefore, except for Nco, the new, flavonoid hyperaccumulating lines can be considered for field cultivation.

A novel central seven-membered BOPYOs: Synthesis, optical properities and optimization of BF2 removal

Many efforts have been made to enrich the variety of BF2 complexes because of their excellent optical properties. However, the investigation on seven-membered ring N, O-chelated BF2 complexes is rare due to their instability with the removal of BF2 unit. Herein, a novel seven-membered ring N, O-chelated BF2 complexes (BOPYOs) with dual-state emission has been synthesized via a facile method. The results of optical properties showed that the fluorescence quantum yield of BOPYO-2 with donor group on 1 and 2-position of 1-indanone unit is much higher than that of BOPYO-1, 3–5 in toluene. The emission spectra of BOPYO-6 or 7 have redshift phenomenon compared with BOPYO-1–5 with weak fluorescence intensity due to their highly distorted structure or intramolecular charge transfer (ICT) effect. BOPYOs show relatively moderate solid emission from orange to deep red color with 596 nm to 686 nm. On the contrary, fluorescence quantum yield of BOPYO-2 in solid is the lowest. The optical properties in solution and solid states are further supported by the single-crystal structure and DFT calculation. Furthermore, the investigation on optimization of BF2 removal shows that the corresponding precursors of BOPYOs could be obtained in protic solvents without adding other catalysts.

Chromosome-scale genome assembly provides insights into flower coloration mechanisms of Canna indica

Canna indica, which produce conspicuous and colorful flowers, are widely appreciated as ornamental plants. We used Pacific Biosciences sequencing (PacBio) and chromosome conformation capture (Hi-C) genome scaffolding to build a high-quality chromosome-scale genome assembly of C. indica and the genome assembly was 821Mb with a contig N50 of 48Mb assembled into nine chromosomes. The genome of C. indica was predicted to contain 31,130 genes and 30,816 genes were functionally annotated. Genome annotation identified 522 Mb (63.59 %) as repetitive sequences. Genome evolution analysis showed that whole-genome duplication occurred 53.4 million years ago. Transcriptome analysis revealed that petal coloration was linked with the expression of genes encoding enzymes involved in anthocyanin biosynthesis, carotenoid biosynthesis, and the methylerythritol phosphate (MEP) pathway. Furthermore, modules of co-expressed genes and hub genes were identified via weighted gene co-expression network analysis. These results suggested that, in Canna indica, deep red petal coloration was regulated by CHS2 and yellow petal coloration was associated with expression of ARF6 and NAC14. Considered together, the current study revealed a high-quality reference genome which may provide new insights into the molecular basis of flower coloration in Canna indica and help enhance the conservation and breeding of ornamental plants in general.

The draft genome reveals early duplication event in Pterocarpus santalinus: an endemic timber species.

A 541Mb draft genome of Pterocarpus santalinus is presented and evidence of whole-genome duplication in the Eocene period with expansion of drought responsive gene families is documented. Pterocarpus santalinus Linn. f., popularly known as Red Sanders, is a deciduous tree, endemic to southern parts of Eastern Ghats in India. The heartwood is highly valued in the international market due to its deep red colour, fragrant heartwood and wavy grained texture. In the present study, a high-quality draft genome of P. santalinus was assembled using short and long reads generated from Illumina and Oxford Nanopore Sequencing platforms, respectively. The haploid genome size was estimated at 541Mb and the hybrid assembly showed 99.60% genome completeness. A total of 51,713 consensus gene set were predicted with 31,437 annotated genes. The age of the whole-genome duplication event in the species was dated at 30-39mya with 95% confidence suggesting early genome duplication event during the Eocene period. Concurrently, phylogenomic assessment of seven Papilionoideae members including P. santalinus grouped the species based on the tribal classification and established divergence of the tribe Dalbergieae from tribe Trifolieae at ~ 54.20mya. A significant expansion of water deprivation/drought responsive gene families documented in the study probably explains the occurrence of the species in dry rocky patches. Additionally, re-sequencing of six diverse genotypes predicted one variant every 27 bases. This report presents the first draft genome in the genus Pterocarpus and the unprecedented genomic information generated is expected to accelerate population divergence studies in the species in relation to its endemic nature, support trait-based breeding programme and aid in development of diagnostic tools for timber forensics.

Evaluation and selection in half-sib progenies of Psidium guajava aiming to identify pink pulp with soft seed progeny

Guava (Psidium guajava L) is one of the commercially important fruit crops being cultivated in India. Of late, pink pulp varieties are getting commercial importance due to its consumer preference. However, pink pulp varieties are having higher number of seeds with bold seed size, which limits its wide acceptance. Hence, in the present study it is aimed to identify genotypes with deep pink or red colour pulp with few soft seeds. The study comprises of 48 half-sib progenies from the group of 337 half-sib progenies of guava var. Arka Kiran based on their flowering and fruiting performance. High and moderate level of genotypic and phenotypic coefficient of variances were recorded for fruit weight, fruit yield, plant height, plant girth, fruit length and fruit circumference indicating that the progenies have adequate genetic variability and these traits are suitable for further improvement through selection. From the results of ICP-MS analysis of two best performing genotypes (PG 1–7 and PG 34–1) and its parent Arka Kiran, it is revealed that PG 1–7 and PG 34–1 had higher level of mineral contents when compared to its parent Arka Kiran. The results of the principal component analyses indicated which were the primary traits and are utilized for progeny selection amongst the population. It is inferred that the PC1 and PC2 exhibited better fruit quality and biochemical traits. Molecular diversity analysis of 12 selected progenies using molecular markers inferred that the better performing progeny PG 1–7(B) and the parent Arka Kiran (A) were distinctly placed in the separate clusters, that shows genetic dissimilarity of genotype PG 1–7 from the parent Arka Kiran, which confirms that PG 1–7 is the potential progeny and it could be prioritized for commercial exploitation amongst the progenies studied.

Synthetic wavelength scanning interferometry for 3D surface profilometry with extended range of height measurement using multi-colour LED light sources

We report three-dimensional surface profilometry with extended range of height measurements using synthetic wavelength scanning interferometry without tunable filters, wavelength-tuning lasers, grating elements. We have used inexpensive multiple colour light emitting diodes (LEDs) and operate them sequentially one by one or combination of two or more colours simultaneously to visualize synthetic wavelength light source. Multiple colour LED light source was synthesized and entire visible range from violet to deep red colour was covered. A wide range of synthetic wavelengths were obtained. Five step phase shifting algorithm was used to recover phase maps with Mirau type interferometer which can be further utilized for 3D height measurements. A simple phase subtraction method was used to reconstruct the phase map at synthetic wavelength. The present system provides extended range of height measurements from sub-wavelength to tens of wavelengths. Experimental results of 3D-surface profile measurements of Si-IC chip and standard step object are presented.

One-Pot Synthesis of Acetylacetonate-Based Isomeric Phosphorescent Cyclometalated Iridium(III) Complexes via Random Cyclometalation: A Strategy for Excited-State Manipulation

The excited-state manipulation of the phosphorescent iridium(III) complexes plays a vital role in their photofunctional applications. The development of the molecular design strategy promotes the creative findings of novel iridium(III) complexes. The current molecular design strategies for iridium(III) complexes mainly depend on the selective cyclometalation of the ligands with the iridium(III) ion, which is governed by the steric hindrance of the ligand during the cyclometalation. Herein, a new molecular design strategy (i.e., random cyclometalation strategy) is proposed for the effective excited-state manipulation of phosphorescent cyclometalated iridium(III) complexes. Two series of new and separable methoxyl-functionalized isomeric iridium(III) complexes are accessed by a one-pot synthesis via random cyclometalation, resulting in a dramatic tuning of the phosphorescence peak wavelength (∼57 nm) and electrochemical properties attributed to the high sensitivity of their excited states to the position of the methoxyl group. These iridium(III) complexes show intense phosphorescence ranging from the yellow (567 nm) to the deep-red (634 nm) color with high photoluminescence quantum yields of up to 0.99. Two deep-red emissive iridium(III) complexes with short decay lifetimes are further utilized as triplet emitters to afford efficient solution-processed electroluminescence with reduced efficiency roll-offs.

Two new species of Haliclona (Demospongiae: Haplosclerida: Chalinidae) from north-eastern Brazilian coastal waters and oceanic islands

Abstract Two new species of Haliclona (Chalinidae, Haplosclerida) are described here from Brazilian oceanic islands and the coast of Ceará State. They derive from collections undertaken between 1999 and 2014, and materials are deposited in the Porifera collection of Museu Nacional in Rio de Janeiro (MNRJ). Haliclona (Halichoclona) insularis sp. nov. can be distinguished from other Haliclona spp. in the western Atlantic by the combination of surface with light to deep red colour intermixed with white to beige areas (occasionally completely beige), white to beige choanosome, small fistular outgrowths, fragile consistency and blunt oxeas (90–175 × 1–5 μm) with irregular tips. Haliclona (Soestella) moraesi sp. nov. is the only western Atlantic species of Haliclona with the combination of thickly encrusting to cushion-shaped habit, purple or light pink colour, and a dense (sub)isotropic skeleton with rounded meshes, and without microscleres. Several attempts to amplify COI mtDNA and 28S C2–D2 rRNA for both species were unsuccessful, in spite of the initial successful extraction of genomic DNA. The number of Haliclona spp. known from the Brazilian coast is now 17. The long gap between species collection and formal description supports the concept of the taxonomic impediment, which is particularly marked in speciose taxa with little morphological disparity, as observed in Haplosclerida.

Lobular Capillary Hemangioma : A Rare Entity

Hemangioma is a relatively common benign proliferation of blood vessels that primarily develops during childhood. Two main forms of hemangioma are: capillary and cavernous. The capillary form presents as a flat area consisting of numerous small capillaries. Cavernous hemangioma appears as an elevated lesion of a deep red color, consisting of large dilated sinuses filled with blood. The purpose of the study was to report the case of a capillary hemangioma in a patient and to describe the successful treatment of this case.

The Identification and Quantitative Analysis of Unusual Keto-Carotenoids in Ripe Fruits of Maclura tricuspidate and Its Potential as a Valuable Source of Cryptocapsin

Ripe fruits of Maclura tricuspidata (MT) are used as food material and a natural colorant in Korea. Although MT fruits have a deep red color due to carotenoid-like pigments, their chemical nature has not been explored in detail so far. The present study aimed at elucidating the chemical structures and composition of carotenoids in MT fruits and changes at different maturity stages. Two carotenoids from saponified MT fruit extract were isolated using repeated silica gel column chromatography. Based on interpretations of spectroscopic data, these compounds were determined as keto-carotenoids, i.e., capsanthin (3,3'-dihydroxy-β,κ-caroten-6'-one) and cryptocapsin (3'-hydroxy-β,κ-caroten-6'-one), and the contents of individual carotenoids were quantified with HPLC based on calibration curves obtained from authentic standards. The contents of capsanthin and cryptocapsin in the sample of saponified MT fruits were 57.65 ± 1.97 µg/g and 171.66 ± 4.85 μg/g as dry weight base (dw). The majority of these keto-carotenoids in the MT fruits were present in esterified forms with lauric, myristic or palmitic acid rather than in their free forms. The results also showed that esterification of these compounds occurred starting from early stage (yellow-brownish stage) of maturation. Considering the high cryptocapsin content, MT fruits can be applied as a potentially valuable source of cryptocapsin for food and medicinal application as well as a source of provitamin A.

Fluorescence Variation in Selective Sensing of Hg2+and Cu2+ Ions By Coumarin-xanthene Fused Optical Probe.

The fluorescent moieties coumarin and xanthene (R6GCP) combined in a single molecule was designed and synthesized. The colorimetric and fluorescent variation of the probe towards the copper and mercury ions sensing is examined. With the added copper/mercury ions to the solution of R6GCP in DMF:H2O (2:8, v/v), the probe showed deep red color from yellow color. The probe showed turn-off and turn-on fluorescence for copper and mercury ion respectively. In the presence of other competing metal ions, the probe showed better sensitivity towards copper and mercury ions. The probe's detection limit found to be 5.29 × 10-6M and 1.24 × 10-5M for Cu2+ and Hg2+ ion respectively by the UV-visible spectral measurement. Fluorescence measurement, the detection limit for the Cu2+ and Hg2+ ions detection by this probe is 1.91 × 10-7M, and 1.32 × 10-8M respectively. 1:1 binding stoichiometry was confirmed between the probe and Cu2+/Hg2+ ions from jobs plot by UV-visible spectral technique. Moreover, R6GCP combined filter paper were prepared. These test paper containing probe could detect Cu2+/Hg2+ ions in real-time with a spontaneous color change.