Chromatic Parameters Research Articles

Evaluating color parameters calculated from digital photographs of sediment cores as a tool in paleoenvironmental reconstruction—A case study using IODP Site U1502 from the South China Sea

Qualitative color data of sediments contain rich information on sediment compositions and have been widely used in paleoenvironmental reconstructions. Digital photographs can produce ultra-high resolution color data of sediment sequences. The characteristics of such data, however, are not yet explored adequately, hindering their use in practice. To fill this gap, in this study we calculated color data from digital photographs of sediment cores from Hole U1502A drilled during International Ocean Discovery Program Expedition 368 in the South China Sea, and compared them with their counterparts measured using a Diffuse Reflectance Spectrophotometer (DRS). We found that the luminance parameter L could be influenced by multiple factors, leading to its behavior being transient, while the chromaticity parameters a* and b* are relatively stable. The down-core patterns of photograph-derived L, a* and b* are comparable with their counterparts derived from DRS measurement, although their absolute values can diverge significantly from those DRS-measured ones. The color of the studied core sediments alternates between grayish-brown and greenish-gray, being pelagic deposits and earthquake-induced turbidite deposits, respectively. Such color cycles had been present since ~13 Ma, revealing a dramatic increase in submarine earthquakes due to subduction of the SCS Plate toward the Philippine Plate. Overall, our study demonstrates that color parameters calculated from sediment photographs could be developed as promising tools for studies relating to paleoenvironmental reconstructions.

Design of Green Silver Nanoparticles Based on Primula Officinalis Extract for Textile Preservation.

The present study aims to bring an addition to biomass resources valorization for environmental-friendly synthesis of nanoparticles. Thus, the green synthesis of silver nanoparticles (AgNPs) was performed, using a novel and effective reducing agent, Primula officinalis extract. The synthesis was optimized by monitoring the characteristic absorption bands, using UV−Vis spectroscopy, and by evaluating the size and physical stability. The phenolic consumption was established using Folin-Ciocâlteu method (1.40 ± 0.42 mg, representing ~5% from the total amount of poly--phenols) and the antioxidant activity was evaluated using chemiluminescence and TEAC methods. The optimum ratio extract to Ag ions was 1:3, for which the AgNPs presented a zeta potential value of −29.3 ± 1.2 mV and particles size of 5−30 nm. For characterization, EDS and XRD techniques were used, along with microscopy techniques (TEM). The AgNPs dispersions were applied on natural textile samples (cotton and wool), as a novel antimicrobial treatment for textile preservation. The treated fabrics were further characterized in terms of chromatic parameters and antimicrobial effect against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Penicillium hirsutum strains. The high percentages of bacterial reduction, >99%, revealed that the AgNPs produced are a good candidate for textiles preservation against microbial degradation.

Comparative assessment of energy analysis, drying kinetics, and biochemical composition of tomato waste under different drying conditions

Food industry generates devastating amount of waste, and it is not easy to handle such huge quantities. Tomato industry also generates tons of waste materials and drying is commonly used for waste tomatoes. This study was conducted to investigate the effect of drying methods on drying kinetics, energy aspects, rehydration, shrinkage, and chromatic parameters of waste tomato samples. The β-caroten, lycopene, antioxidant, antiradical activity, total phenolics, flavonoids, ascorbic acid, fatty acid, and mineral contents of dried samples were also evaluated. Jena&Das model best estimated the drying process of tomato. The greatest color change values were obtained from air-convective (28.40) drying and the lowest from hybrid (16.03) drying. The highest rehydration capacity was determined in greenhouse (4.06) drying. Microwave drying was identified as the most efficient system in terms of energy (8.67%) and thermal efficiency (7.49%). Effective moisture diffusivity values ranged from 5.54×10–11 to 1.30×10–8 m2s–1. The highest total phenolics and ascorbic acid values were obtained from greenhouse drying. The greatest β-carotene and fatty acid contents were recorded in air convective drying. Microwave drying had the highest FRAP and flavonoid content.

Silver nano/microparticle toxicity in the shrimp Litopenaeus vannamei (Boone, 1931)

The effects of silver nano/microparticles (AgP) on juvenile Litopenaeus vannamei shrimp were evaluated through several responses, aiming to use it as a prophylactic and therapeutic method. Shrimps (3.19 ± 0.13 g) were exposed to clear water for 3 h with increasing concentrations of nanosilver (0; 25; 100; and 400 μg/l). After 3 h of exposure, they were transferred to water without nanosilver for 30 days (recovery). The weight gain and weekly growth were not affected by AgNP. Total antioxidant capacity (ACAP) increased in the hepatopancreas (exposure period) and gills (recovery) in shrimp exposed to AgNP. In muscle, ACAP was induced in shrimp exposed to 100 μg/l AgNP (exposure). In the gills, there was an increase in TBARS in shrimp exposed to 100 μg/l AgNP (recovery). In the concentration of protein-associated sulfhydryl groups (P-SH), a decrease was observed in the hepatopancreas (recovery) in the 100 μg/l AgNP treatment. In chromaticity parameters, an increase in reddish tones was observed in shrimp exposed to 100 μg/l AgNP (recovery). An increase in granular hemocytes was verified in shrimp exposed to 25 and 400 μg/l AgNP during exposure. Tissues analyzed histologically showed normal patterns without apoptosis or necrosis processes, and after 30 d of recovery, only in one muscle sample of shrimp exposed to μg/l of AgNP was silver detected. It is concluded that a prophylactic action of short duration (3 h) mostly did not affected the welfare of shrimp L. vannamei and can be considered its use as a therapeutic strategy.

Comparison of Chromatic and Spectrophotometric Properties of White and Red Wines Produced in Galicia (Northwest Spain) by Applying PCA.

Wine is a complex matrix composed of numerous substances and color has an important influence on its quality and consumer acceptance. Color is affected by numerous factors such as pre-fermentation and fermentation operations, ageing, contact or addition of certain substances. In this study, different chromatic parameters were determined in 99 wines (58 red and 41 white) made from Galician (Northwest Spain) grape varieties. These parameters were obtained by using simple, rapid, and inexpensive spectrophotometric methodologies: color intensity, hue, total polyphenols content (Total Polyphenol Index TPI, Folin–Ciocalteu index, FCI), total anthocyans, total tannins, and color coordinates measured by the CIELab system. The influence of ageing in barrels (red wines) or using chips (white and red wines) on these parameters was also studied. A principal component analysis (PCA) was carried out to characterize the wines according to their chromatic characteristics. Application of PCA to the experimental data resulted in satisfactory classifications of studied white and red wines according to the cited enological practices.

On the algorithmic complexity of determining the AVD and NSD chromatic indices of graphs

A proper k-edge-colouring ϕ of a graph G is an assignment of colours from {1,…,k} to the edges of G such that no two adjacent edges receive the same colour. If, additionally, ϕ guarantees that no two adjacent vertices of G are incident to the same sets or sums of colours, then ϕ is called an AVD or NSD edge-colouring, respectively (the abbreviations AVD and NSD standing for “adjacent vertex distinguishing” and “neighbour sum distinguishing”). The chromatic index χ′(G) of G is the smallest k such that proper k-edge-colourings of G exist. Similarly, the AVD and NSD chromatic indices χAVD′(G) and χNSD′(G) of G are the smallest k such that AVD and NSD k-edge-colourings of G exist, respectively. These chromatic parameters are quite related, as we always have χNSD′(G)≥χAVD′(G)≥χ′(G).By a well-known result of Vizing, we know that, for any graph G, we must have χ′(G)∈{Δ(G),Δ(G)+1}. Still, determining χ′(G) is NP-hard in general. Regarding χAVD′(G) and χNSD′(G), it is conjectured that, in general, they should always lie in {Δ(G),Δ(G)+1,Δ(G)+2}.In this work, we prove that determining whether a given graph G has AVD or NSD chromatic index Δ(G) is NP-hard for every Δ(G)≥3. We also prove that, for a given graph G, determining whether the AVD or NSD chromatic index is Δ(G)+1 is NP-hard for every Δ(G)≥3. Through other NP-hardness results, we also establish that there are infinitely many graphs for which the AVD and NSD chromatic indices are different. We actually come up, for every k≥4, with infinitely many graphs with maximum degree k, AVD chromatic index k, and NSD chromatic index k+1, and similarly, for every k≥3, with infinitely many graphs with maximum degree k, AVD chromatic index k+1, and NSD chromatic index k+2. In both cases, recognising graphs having those properties is actually NP-hard.

Evaluation of Marble Alteration Processes

Abstract The aim of the paper consists in the study of three Romanian types of marble (Ruschita, Albesti, Carrara) with different compositions in different temperature conditions, for different periods of time. The three samples were exposed to two different types of treatments: 25 cycles of freeze-thaw (according to SR EN 12371) and 3 cycles of exposure to high temperatures (400 °C for 1 hour). Following the freeze-thaw cycles, small differences in chromatic parameters could be observed (∆E = 2.2 for Carrara Italia marble and ∆E = 7.2 for Rușchița pink marble). The freezing coefficient for all samples is low (0.016% - 0.029%). Following exposure to high temperature treatment, the samples show large differences in chromatic parameters (∆E = 43.47 for Albesti marble) and significant changes in gloss. The surface of the samples showed cracks and microcracks. Based on the results of this study, the following conclusions can be drawn: Thermal cycles can cause the mechanical disintegration of the outer part of the marble, starting from the discontinuities contained in the rock and between the faces between the different minerals that form the stone. Exposure to high temperatures will result in a loss of adhesion between the surface grains on the sample surface. The degradation processes have been investigated.

Physiological and quality changes in fresh-cut mango fruit as influenced by cold plasma

In this study, fresh-cut (FC) mango cubes were treated with cold plasma (CP) at 75 kV for 3 min using a dielectric barrier discharge (DBD) generator and then stored at 15 °C for 4 d to simulate a shelf life, during which the quality parameters and related physiological metabolisms were evaluated. The results showed that CP treatment effectively delayed the declines in organoleptic and nutritional qualities in FC mangoes, as manifested by higher retentions of chromaticity parameters (L*, a* and b*), firmness, soluble solids content (SSC), titratable acidity (TA), SSC/TA ratio and carotenoids content in CP-treated samples during storage. CP treatment repressed the generation of reactive oxygen species (ROS) (O2-. and H2O2) and reduced the accumulation of malondialdehyde (MDA), thus reducing oxidative damage to FC mangoes. Inhibition of browning-related phenolic oxidation, as demonstrated by higher contents of total phenolics and flavonoids accompanied by lower activities of polyphenol oxidase (PPO) and peroxidase (POD), was noted in CP-treated FC mangoes compared to control FC fruit. CP treatment also maintained antioxidant capacity in stored FC mangoes by increasing the contents of ascorbic acid (AsA) and reduced glutathione (GSH) and enhancing the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR). In addition, CP treatment markedly inhibited the growth of total microbial counts, thus contributing to the improvement of edible safety in FC mangoes. The results suggest that CP treatment could be a promising preservation technology for improving the quality and extending the shelf life of FC mango fruit.

Balance PCE, AVT and CRI for good eye comfort semi-transparent organic photovoltaics via Ga2O3 or In2O3 electron collection layers

One of the promising applications for semi-transparent organic solar cells (ST-OSCs) is using as photovoltaic glass windows due to their suitable transparency, comfortable and adjustable color. However, it is difficult to achieve good eye comfort ST-OSCs with suitable average visible transmittance (AVT), power conversion efficiency (PCE) and color rendering index (CRI) because the three factors affect and restrict mutually. To realize ST-OSCs with high performance, theoretical transmittance spectra of ST-OSCs are obtained using the finite-difference time-domain (FDTD) simulation, and then the theoretical optimized structural parameters with appropriate AVT and CRI are achieved. The experimental ST-OSCs output is analyzed under the guidance of theory, and PM6:Y6-based ST-OSCs with Ga 2 O 3 or In 2 O 3 electron collection layers (ECLs) demonstrate outstanding power-generating and chromatic parameters. The PCE for devices with Ga 2 O 3 ECL gets up to 12.6% with an AVT of 22.5% and a CRI of 86.94, and the PCE for devices with In 2 O 3 ECL reaches up to 12.7% with an AVT of 21.5% and a CRI of 88.29. Apparently, the two deep-blue devices guarantee comfortable visual sensations when seeing through the devices, and this work offers a simple approach to achieve power-generating glass with good eye comfort color in energy-saving skyscrapers. • Good eye comfort ST-OSCs were optimized using finite-difference time-domain. • Ga 2 O 3 and In 2 O 3 were utilized as ECLs for good eye comfort OSCs, respectively. • Ga 2 O 3 -based devices show a PCE of 12.6% with an AVT of 22.5% and a CRI of 86.9. • In 2 O 3 -based devices show a PCE of 12.7% with an AVT of 21.4% and a CRI of 88.3.

Induction of stress defense response and quality retention in minimally processed peaches through the application of gamma irradiation treatments

Consumers demand fruit and vegetable products "on the go" that maintain color, flavor, nutritional and bioactive compounds almost equal to fresh products. Irradiation represents an effective technology traditionally used in fruit and vegetable as a phytosanitary treatment to preserve food quality and safety. In the present study we evaluated the effect of gamma irradiation treatments at several doses (0, 0.1, 0.3, 1.0, 2.5 kGy) on the quality and biochemical aspects of minimally processed peaches (Prunus persica L. Batsch) with low oxygen permeability packaging. During minimal processing, peach slices were treated in an antioxidant solution containing 1 % ascorbic acid and 0.5 % citric acid for 2 min. Trays of minimally processed peaches were irradiated packed inside cardboard boxes. Changes in color, firmness and polyphenoloxidase (PPO) and peroxidase (POD) activities of peaches were analyzed at different storage times (0, 7, 14 d) at 4 °C. In addition, the stress response of plant to these treatments was assessed by using the induction of heat shock proteins (HSP) as a biochemical marker. Results show that irradiation caused no substantial changes in chromatic parameters, although an immediate reduction in firmness and POD activity was observed, proportional to the increased doses applied. In turn, PPO activity remained stable while the activity of some of its isoenzymes decreased for doses higher than 0.3 kGy. The overexpression of HSP, only detected for irradiation doses of 0.1 and 0.3 kGy, in coincidence with the best performing treatments, constitutes a relevant finding not previously reported in fruit. Therefore, low doses of irradiation promoted the physiological and biochemical defense mechanisms of the fruit. HSP could thus be used in plant tissues as a biomarker of the stress brought about by exposure to irradiation, capable of preventing physiological damage. These preliminary results suggest that irradiation treatments (up to 1.0 kGy) in combination with modified atmosphere packaging (from 19 % and 10 % O2 at 0 d to 3 % and 15 % CO2 at 14 d of storage) could render high quality peach products with an extended shelf life.

Aronia Extracts in the Production of Confectionery Masses

The article examines the opportunity to use extracts and Aronia melanocarpa (Michx.) Elliot fruit powders in the production of sugar confectionery for the substitution of synthetic dyes. In the technology of manufacturing confectionery masses, synthetic dyes are used that can cause various allergic reactions, as well as hyperactivity syndrome and lack of concentration in children. The composition of hydroalcoholic extracts was analyzed, and the metabolites of polyphenols, individual anthocyanins and organic acids were quantified. Antioxidant capacity and CIELab chromatic parameters were tested. The technology for manufacturing confectionary masses with extract and powder of aronia was developed. The sensory profile, physicochemical and microbiological quality parameters, antioxidant activity and color characteristics of the confectionary masses with the extract and powder of aronia addition were determined on the 1st and 50th day from the production date. The evolution of DPPH antioxidant activity of confectionery masses during storage was measured in vitro, in the conditions of gastric digestion. The results showed that Aronia melanocarpa (Michx.) Elliot extract is rich in polyphenols, flavonoids and tannins, the main organic acids being represented by malic, citric, acetic and ascorbic acid. During the 50th storage day, the antioxidant activity was higher in confectionery masses containing aronia compared to the control. The sensory and microbiological testing of confectionary masses demonstrated that the combination of extract and aronia powder ensures the optimal shelf life and organoleptic scores. It was demonstrated that during the storage of confectionery masses with aronia, the physicochemical indicators of quality were in accordance with the regulated admissible values. Positive effects of aronia were observed on confectionery masses’ color saturation. These results underline the opportunity to use aronia extract and/or powder in confectionery industry to replace synthetic dyes and obtain products with enhanced functionality.

An in‐depth study on shelf‐life indicators of red raspberry (Rubus idaeusL.) in correlation to putrescine treatments and storage duration

Raspberries are delicate fruits and are quite quickly perishable due to many reasons. Therefore, the variation of weight loss (WL), decay rate (DR), titratable acidity (TA), soluble solids content (SSC), pH, respiration rate (RR), fruit density (FD), chromatic parameters (L, a, b, chroma, hue angle, and ΔE), phenolics and flavonoids, and organic acids and vitamin C fresh red raspberries were investigated at 15-day intervals during storage period at 0 (control), 0.3, 0.5, and 1 mM L−1 PUT for 30 days. The physiochemical properties and biochemical composition of red raspberries changed significantly (except for pH, a, b, and hue angle) with increasing PUT concentrations and storage duration (p < .05), and WL, TA, pH, RR, b, chroma, hue angle, and ΔE values were fitted to the zero-order kinetic model; the values of DR, L, and a followed the first-order kinetic model; on the other hand, the values of SSC and FD followed the second-order kinetic model. Biochemical contents were determined to fit the first-order and second-order kinetic models. As a result of the cluster analysis, two groups were formed as a storage group on the 15th day and a storage group on the 30th day. Novelty impact statement This study ensures useful information for improving the quality properties of red raspberries considering the combined effect of putrescine treatment and storage duration. Putrescine treatment is a good alternative for preservation studies to substitute the control treatments. This putrescine treatment enhances the quality of products with short duration of storage.

Comparison Study of Nontreated and Fermented Wheat Varieties 'Ada', 'Sarta', and New Breed Blue and Purple Wheat Lines Wholemeal Flour.

Simple SummaryNowadays, consumers are looking for higher functional value products that can meet the nutritional requirements of functional compounds. Wheat is the most important crop in the world, and to improve its functional properties, colored wheat has become a very attractive option. However, most of the valuable compounds of the wheat cereal (including colored) are located in the outer layer of the cereal. From this point of view, application of non-refined (wholemeal) flour became very important. The aim of this study was to analyze and compare physico-chemical and microbiological parameters of the nontreated ‘Ada’, ‘Sarta’, and new breed blue and purple wholemeal wheat lines with those fermented with lactic acid bacteria (LAB) strains (Pediococcus acidilactici, Liquorilactobacillus uvarum, Lactiplantibacillus plantarum). It was found that all of the used LAB strains are suitable for the tested wheat wholemeal fermentation. However, most of the analyzed parameters were influenced by the wheat variety, the type of LAB used for fermentation, and their interaction. Despite the fact that fermented wheat wholemeal showed a large number of viable LAB, good acidification rates, and a more diverse volatile compound profile. further studies are needed to indicate the technological parameters that lead to the lowest BA formation and mycotoxin degradation.The aim of this study was to analyze and compare the acidity, microbiological, and chromaticity parameters; fatty acid (FA) and volatile compound (VC) profiles; and biogenic amine (BA), macro- and microelement, and mycotoxin concentrations in nontreated ‘Ada’, ‘Sarta’, and new breed blue (DS8472-5) and purple (DS8526-2) wheat lines wholemeal (WW) with those fermented with lactic acid bacteria (LAB) possessing antimicrobial/antifungal properties, isolated from spontaneous sourdough: Pediococcus acidilactici-LUHS29, Liquorilactobacillus uvarum-LUHS245, Lactiplantibacillus plantarum-LUHS122). All the fermented WW showed >8.0 log10 CFU/g of LAB count, and the type of LAB was a significant factor in the WW acidity parameters. Phenylethylamine was the predominant BA in WW, and the wheat variety (WV), the type of LAB, and their interaction were significant factors on the BA formation. Despite the fact that some differences in trace element concentrations in WW were obtained, in most of the cases fermentation was not a significant factor in their content. The main FAs in WW were palmitic acid, all-cis,trans-octadecenoic acid, and linoleic acid. Fermented WW showed a more diverse VC profile; however, the influence of fermentation on deoxynivalenol in WW was varied. Finally, further studies are needed to indicate the technological parameters that would be the most effective for each WV, including the lowest BA formation and mycotoxin degradation.

Influence of Wine pH and Ethanol Content on the Fining Efficacy of Proteins from Winemaking By-Products.

Wine color and limpidity are important aspects of consumer preferences. The alteration of these parameters can damage wine’s appearance but also its mouthfeel characteristics due to its relationship with attributes such as bitterness and astringency. Fining is a practice usually used in enology to modulate undesirable wine organoleptic attributes. However, there are several factors that influence this technique. In this study, the influence of wine pH and ethanol content on grape seed protein fining efficacy has been assessed. Wine clarification, total phenolic and flavanol contents, antioxidant activity, and chromatic parameters have been investigated before and after fining process. The most noticeable clarifying effects were observed for the experimental wines with a lower pH and ethanol content. Control of these factors will make it possible to modulate the main organoleptic properties of the wine, also avoiding the addition of large amounts of fining agents and thus providing greater versatility to wineries during winemaking. Furthermore, our findings indicated that grape seed protein is a potential alternative to other plant-based fining proteins commonly used in winemaking. Its effects on clarification and color quality have been found to be comparable to those of potato protein and significantly better than those of pea protein.

Estudio del envejecimiento acelerado del aroma, el color y los parámetros fisicoquímicos de vinos Tannat

In this work, different techniques were evaluated to achieve accelerated aging of the wine: ultrasound (US), gamma irradiation (RG) and high pressure (AP). The experimental conditions for each treatment were as follows: US, sequences of 30 and 60 minutes at 20 kHz; RG, three doses were analyzed (1, 3 and 6 kGy); for AP a constant pressure of 650 MPa was applied varying the application time (15, 30, 60 and 120 minutes). The wines were characterized by their basic physicochemical characteristics, their volatile profile (GC-MS) and color analysis (CIELAB). The same wine but without any treatment was used as a control. The results obtained showed that US treatment did not produce significant differences with respect to the control for all the conditions tested. For AP, significant differences were obtained with respect to the control in color (decrease in all the chromatic parameters) and content of volatile compounds (increase in the terpenes and esters contents). The GR treatment produced the greatest changes with respect to the control wine, with an increase in all the chromatic parameters with increasing radiation dose. The volatile profile showed an increase in 3-oxo-α-ionol, ho-diol and ethyl lactate content, all desirable changes during natural ageing.

High-pressure processing treatment of beef burgers: Effect on Escherichia coli O157 inactivation evaluated by plate count and PMA-qPCR.

Propidium monoazide coupled to real time PCR (PMA-qPCR) is a novel methodology proposed for the quantification of viable bacteria in food after microbial inactivation treatments. The aim of this work was to assess the effectiveness of different pressure levels on the lethality of a pool of Escherichia coli O157 strains in beef burgers by plate count and PMA-qPCR using uidA as target gene. Also, the effect on native microbiota counts, E. coli O157 counts, and physiochemical parameters of beef burgers during storage in refrigeration and frozen conditions were assessed. The treatment at 600MPa for 5min was the most lethal and was selected for the evaluation of bacteria behavior under storage conditions. Native microbiota and E. coli O157 were not recovered during refrigerated and frozen storage (4°C for 7 days and -18°C for 35 days). Cooking weight loss, pH, chromatic parameters, and texture were affected by HPP. PRACTICAL APPLICATION: Practical Application: PMA-qPCR can be used as an alternative to assess microbial inactivation by different high pressure processing (HPP) conditions (pressure level, holding time and temperature) more rapidly than conventional plate counts. In addition, it has the benefit of being able to quantify viable but nonculturable bacteria from contaminated beef burgers after HPP. Moreover, this novel technique generates less pathogenic residues, which minimizes workers' exposure to human biohazards.

Effect of substituted 2,2′-bipyridine derivatives on luminescence characteristics of green emissive terbium complexes: Spectroscopic and optical analysis

Heteroleptic ternary terbium complexes with general representation as [Tb(acac)3 L] have been prepared through single step path with acetylacetone (acac) as chromophoric and substituted 2,2ꞌ-bipyridine as auxiliary (L) moieties. The synthesized complexes are characterized systematically through elemental, spectroscopic and thermogravimetric analyses. The infra-red and proton nuclear magnetic resonance spectra are consistent with the formation of complexes. Green emission is observed for the synthesized terbium complexes in solid form and in dichloromethane (DCM) solvent due to 5D4→7F5 transition. The chromaticity parameters have estimated high color purity of the complexes and their coordinates positioned in the green region of the CIE triangle. The singlet and triplet state energy of 2,2ꞌ-bipyridine (Bpy) and 2,2′-bipyridine dihydrobromide (DBr) show the efficient sensitization of Tb3+ ion in synthesized complexes by respective ligands. The bright green emission and the values of band gap indicate the utilization of synthesized complexes in the fabrication of displays.

Hybrid confocal fluorescence and photoacoustic microscopy for the label-free investigation of melanin accumulation in fish scales

Lower vertebrates, including fish, can rapidly alter skin lightness through changes in melanin concentration and melanosomes’ mobility according to various factors, which include background color, light intensity, ambient temperature, social context, husbandry practices and acute or chronic stressful stimuli. Within this framework, the determination of skin chromaticity parameters in fish species is estimated either in specific areas using colorimeters or at the whole animal level using image processing and analysis software. Nevertheless, the accurate quantification of melanin content or melanophore coverage in fish skin is quite challenging as a result of the laborious chemical analysis and the typical application of simple optical imaging methods, requiring also to euthanize the fish in order to obtain large skin samples for relevant investigations. Here we present the application of a novel hybrid confocal fluorescence and photoacoustic microscopy prototype for the label-free imaging and quantification of melanin in fish scales samples with high spatial resolution, sensitivity and detection specificity. The hybrid images are automatically processed through optimized algorithms, aiming at the accurate and rapid extraction of various melanin accumulation indices in large datasets (i.e., total melanin content, melanophores’ area, density and coverage) corresponding to different fish species and groups. Furthermore, convolutional neural network-based algorithms have been trained using the recorded data towards the classification of different scales’ samples with high accuracy. In this context, we demonstrate that the proposed methodology may increase substantially the precision, as well as, simplify and expedite the relevant procedures for the quantification of melanin content in marine organisms.

Controlling growth of phototrophic biofilms on limestone using CaZn2(OH)6·2H2O and ZnO nanoparticles

AbstractBACKGROUNDDeterioration by microbial activity is common in the built cultural heritage, where phototrophic microorganisms are primary colonizers that form complex communities associated with heterotrophic microorganisms. Therefore, this article analyses the antiphototrophic effect of ZnO and CaZn2(OH)6·2H2O (CZ) nanoparticles (NPs) on three limestone lithotype coupons (Xcambo, red limestone and shellstone). The nanomaterials were obtained via sol–gel (SG), hydrothermal (HT) and mechanochemical (MS) routes and characterized using powder X‐ray diffraction and scanning electron microscopy. Two concentrations of NPs (5000 and 10 000 μg mL−1) were applied to the coupons; afterwards, phototrophic microorganisms isolated from Chichén‐Itzá, Yucatan were inoculated. The percentage of protection was calculated with ImageJ software, and chromatic parameters were measured to identify visible changes in the stones.RESULTSThe results show differences in the protective effect and color variations depending on the nanomaterials and phototrophic microorganisms applied in the limestone coupons. CZ and ZnO protect more than 72% on the surface of shellstone and Xcambo except for ZnO‐SG in shellstone. The growth of Gloeocapsa sp. in red limestone with ZnO‐SG and CZ‐SG was equal to or greater than that of the control without NPs. In general, the NPs protect the limestone surface against phototrophic microorganisms up to 10% more than commercial algaecide. The coupons treated with ZnO‐HT and CZ‐HT have greater protection against biofilm formation than other coatings.CONCLUSIONSIn general, the coatings show a higher antiphototrophic protection than the controls, mainly the CZ‐HT coatings, with better results at lower concentration. Therefore, these nanomaterials could be used to inhibit the formation of biofilms on built cultural heritage. © 2022 Society of Chemical Industry (SCI).

Oil From Three Aguaje Morphotypes (Mauritia flexuosa L.f.) Extracted by Supercritical Fluid With CO2: Chemical Composition and Chromatic Properties

The chemical composition and CIELAB color parameters of oil from three aguaje morphotypes (Mauritia flexuosa L.f.) extracted by supercritical carbon dioxide was investigated. By chromatography (HPLC and GC), spectrometry (UV/vis), and digital image colorimetry (digital camera), carotenoids, tocopherols, tocotrienols, fatty acids, total polyphenols, and CIELAB color space were analyzed. These findings showed that the oil obtained from morphotype 3 was superior in several analytes (carotenoids, polyphenols, oleic acid, β-sitosterol, campesterol, and stigmasterol), while morphotype 2 and morphotype 1 showed very close profiles. The most similar chemical components in the oils of the three morphotypes were stigmasterol (16.00 to 17.81%), β-sitosterol (66.39 to 68.94%), palmitic acid (15.56 to 20.69%), and oleic acid (73.29 to 79.54%). The chromatic parameters (L*, a*, b*, and Cab*) were quite different except for the hue angle (hab) (66.55 to 69.71 U), which showed some similarity. Aguaje oil is an interesting resource that stands out for its high content of carotenoids. All three morphotypes may be suitable for potential commercial applications.