Segui questo link per vedere altri tipi di pubblicazioni sul tema: Pigments.
Articoli di riviste sul tema "Pigments"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Pigments".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Bacarji, Edgar, Fabíolla Xavier Rocha Ferreira, Larissa Alves de Souza e Henrique Santiago de Camargo. "BLOCOS MODULARES NÃO CONVENCIONAIS COM SUBPRODUTOS DE BRITAGEM: INFLUÊNCIA DE PIGMENTOS INORGÂNICOS". REEC - Revista Eletrônica de Engenharia Civil 19, n. 1 (12 maggio 2023): 24–35. http://dx.doi.org/10.5216/reec.v19i1.74966.
Testo completoAbstract (sommario):
RESUMO: Esta pesquisa teve como objetivo avaliar o efeito da adição dos pigmentos inorgânicos nas cores vermelha, amarela e verde em blocos destinados à construção modular. Os blocos foram fabricados com o traço 1:5 (cimento: agregados totais), em massa, utilizando como agregados areia artificial, fíler e micro fíler; todos, subprodutos de britagem. Foram incorporados 0% (traço de referência), 5%, 10% e 15% dos pigmentos em relação à massa do cimento e em substituição parcial ao fíler. Para a confecção dos blocos, utilizou-se uma prensa hidráulica com capacidade de prensagem de 8,0 tf. Foram determinadas as densidades dos blocos e realizados os ensaios de absorção total de água e de resistência à compressão. Além disso, com o fim de analisar os efeitos dos pigmentos sobre a porosidade dos blocos, foram realizados ensaios de Microscopia Eletrônica de Varredura (MEV), que indicaram uma microestrutura mais densa para os blocos que apresentaram menor absorção total de água. Verificou-se ainda que o efeito da adição dos pigmentos varia conforme o formato dos grãos e porcentagem de pigmento. Os blocos que tiveram melhores desempenhos mecânicos foram os com 5% de pigmento amarelo, 10% e 15% de pigmento verde e 15% de pigmento vermelho, todos estes com desempenhos superiores ao desempenho dos blocos de referência, sem pigmento. ABSTRACT: This research aimed to evaluate the effect of the addition of inorganic pigments in red, yellow, and green colors in blocks intended for modular construction. The blocks were manufactured with the mix 1:5 (cement: total aggregates), in mass, using artificial sand, filler and micro filler as aggregates; all crushing by-products. Reference mix (0%) and 5%, 10% and 15% of the pigments were incorporated in relation to the cement mass and in partial replacement of the filler. To make the blocks, a hydraulic press with a pressing capacity of 8.0 ton was used. Block densities were determined, and total water absorption and compressive strength tests were performed. Furthermore, to analyze the effects of pigments on the porosity of the blocks, Scanning Electron Microscopy (SEM) tests were carried out, which indicated a denser microstructure for the blocks that showed lower total water absorption. It was also found that the effect of adding pigments varies according to the shape of the grains and the percentage of pigment. The blocks that had the best mechanical performance were those with 5% of yellow pigment, 10% and 15% of green pigment and 15% of red pigment, all of which performed better than the reference blocks without pigment.
2
Lin, Lan, e Jianping Xu. "Production of Fungal Pigments: Molecular Processes and Their Applications". Journal of Fungi 9, n. 1 (28 dicembre 2022): 44. http://dx.doi.org/10.3390/jof9010044.
Testo completoAbstract (sommario):
Due to the negative environmental and health effects of synthetic colorants, pigments of natural origins of plants and microbes constitute an abundant source for the food, cosmetic, textile, and pharmaceutical industries. The demands for natural alternatives, which involve natural colorants and natural biological processes for their production, have been growing rapidly in recent decades. Fungi contain some of the most prolific pigment producers, and they excel in bioavailability, yield, cost-effectiveness, and ease of large-scale cell culture as well as downstream processing. In contrast, pigments from plants are often limited by seasonal and geographic factors. Here, we delineate the taxonomy of pigmented fungi and fungal pigments, with a focus on the biosynthesis of four major categories of pigments: carotenoids, melanins, polyketides, and azaphilones. The molecular mechanisms and metabolic bases governing fungal pigment biosynthesis are discussed. Furthermore, we summarize the environmental factors that are known to impact the synthesis of different fungal pigments. Most of the environmental factors that enhance fungal pigment production are related to stresses. Finally, we highlight the challenges facing fungal pigment utilization and future trends of fungal pigment development. This integrated review will facilitate further exploitations of pigmented fungi and fungal pigments for broad applications.
3
LYONS, ANTHONY V., e GREGG REED. "Pigmented aqueous barrier coatings". November 2020 19, n. 11 (1 dicembre 2020): 551–58. http://dx.doi.org/10.32964/tj19.11.551.
Testo completoAbstract (sommario):
The desire for more sustainable packaging has led to the development of new packaging materials that are fiber based. Aqueous coatings are a pathway to improve the recyclability of these materials. Pigments used in these coatings can improve the performance of the coating and reduce cost while further improving the recyclability. Mineral pigments are also considered to be compost neutral. In this paper, we provide the reader a better fundamental understanding of the mechanisms by which pigments work in barrier coatings. A pigment’s mineralogy and physical characteristics are important to how it will perform, and there have been recent pigment developments that improve coating performance. This paper shows that some pigments are better than others in particular barrier applications. Also, pigmented base or pre-coats can be used to prepare the surface for more highly functional coatings that go on top, improving the barrier function of packaging material and reducing overall cost. Finally, the converting operation is of major importance in driving formulation choices for barrier applications.
4
Leow, M. E. L., R. K. K. Ow, S. Valiyaveettil, M. H. Lee e R. W. H. Pho. "Colourfast pigments in silicone hand and maxillofacial prostheses". Prosthetics and Orthotics International 26, n. 2 (agosto 2002): 124–34. http://dx.doi.org/10.1080/03093640208726635.
Testo completoAbstract (sommario):
This study addresses the clinical problem of long-term discolouration of silicone hand and maxillofacial prostheses. Seven (7) pigment hues, considered essential for achieving a suitable tissue colour-matched prosthesis, were compared for their colourfast property, across three selected proprietary formulations. In all, a series of 21 pigments, were tested for colourfastness. The pigments, presenting as suspensions (PS), pastes (PP) and dry pigments (PD), were exposed, over nine months, to ultraviolet light, elevated temperatures and varying concentrations of salinity. Colour change of the pigments was measured and expressed as Commission International de l'Eclairage (CIE) (L∗, a∗, b∗) units. Pigment discoloration was significantly attributed to ultraviolet light. Pigmented and clear silicone samples showed a “yellowing” (+Δb∗) effect. Lighter pigments became darker (-ΔL∗) in shade. Pigment samples at the elevated temperature of 50°C showed significant but small colour change (?E, 0.77 to 3.63). Only the master blue pigment (PS-4) recorded a higher ?E, 6.26 at 50°C. At a moderate temperature of 35°C, both pigmented and clear silicone test samples remained relatively colourfast. Comparison was made to control samples, stored in darkness, at 26°C. The pigments were generally colourfast (ΔE<6 units) to saline solutions of 0.15M and 5.0M concentrations. Only the monastral red (PD-3) pigment recorded a ΔE of 9.33, in 0.15M normal saline, simulating the vulnerability of this pigment to the salinity of human sweat. Pigment hues were systematically ranked according to colourfastness. Pigment suspensions were more colourfast than pigment pastes.
5
Ramesh, Chatragadda, V. R. Prasastha, Mekala Venkatachalam e Laurent Dufossé. "Natural Substrates and Culture Conditions to Produce Pigments from Potential Microbes in Submerged Fermentation". Fermentation 8, n. 9 (14 settembre 2022): 460. http://dx.doi.org/10.3390/fermentation8090460.
Testo completoAbstract (sommario):
Pigments from bacteria, fungi, yeast, cyanobacteria, and microalgae have been gaining more demand in the food, leather, and textile industries due to their natural origin and effective bioactive functions. Mass production of microbial pigments using inexpensive and ecofriendly agro-industrial residues is gaining more demand in the current research due to their low cost, natural origin, waste utilization, and high pigment stimulating characteristics. A wide range of natural substrates has been employed in submerged fermentation as carbon and nitrogen sources to enhance the pigment production from these microorganisms to obtain the required quantity of pigments. Submerged fermentation is proven to yield more pigment when added with agro-waste residues. Hence, in this review, aspects of potential pigmented microbes such as diversity, natural substrates that stimulate more pigment production from bacteria, fungi, yeast, and a few microalgae under submerged culture conditions, pigment identification, and ecological functions are detailed for the benefit of industrial personnel, researchers, and other entrepreneurs to explore pigmented microbes for multifaceted applications. In addition, some important aspects of microbial pigments are covered herein to disseminate the knowledge.
6
Lebeau, Juliana, Thomas Petit, Mireille Fouillaud, Laurent Dufossé e Yanis Caro. "Alternative Extraction and Characterization of Nitrogen-Containing Azaphilone Red Pigments and Ergosterol Derivatives from the Marine-Derived Fungal Talaromyces sp. 30570 Strain with Industrial Relevance". Microorganisms 8, n. 12 (3 dicembre 2020): 1920. http://dx.doi.org/10.3390/microorganisms8121920.
Testo completoAbstract (sommario):
Many species of Talaromyces of marine origin could be considered as non-toxigenic fungal cell factory. Some strains could produce water-soluble active biopigments in submerged cultures. These fungal pigments are of interest due to their applications in the design of new pharmaceutical products. In this study, the azaphilone red pigments and ergosterol derivatives produced by a wild type of Talaromyces sp. 30570 (CBS 206.89 B) marine-derived fungal strain with industrial relevance were described. The strain was isolated from the coral reef of the Réunion island. An alternative extraction of the fungal pigments using high pressure with eco-friendly solvents was studied. Twelve different red pigments were detected, including two pigmented ergosterol derivatives. Nine metabolites were identified using HPLC-PDA-ESI/MS as Monascus-like azaphilone pigments. In particular, derivatives of nitrogen-containing azaphilone red pigment, like PP-R, 6-[(Z)-2-Carboxyvinyl]-N-GABA-PP-V, N-threonine-monascorubramin, N-glutaryl-rubropunctamin, monascorubramin, and presumed N-threonyl-rubropunctamin (or acid form of the pigment PP-R) were the major pigmented compounds produced. Interestingly, the bioproduction of these red pigments occurred only when complex organic nitrogen sources were present in the culture medium. These findings are important for the field of the selective production of Monascus-like azaphilone red pigments for the industries.
7
Widyaningrum, D., N. F. Sadek, D. Cecilia, R. A. Oktafika e F. Tedjakusuma. "The effect of temperature and encapsulation on the stability of microalgae pigments". IOP Conference Series: Earth and Environmental Science 1352, n. 1 (1 maggio 2024): 012090. http://dx.doi.org/10.1088/1755-1315/1352/1/012090.
Testo completoAbstract (sommario):
Abstract Microalgae pigments are gaining interest in food industry applications as food additives by providing color and health benefits such as antioxidant properties. The pigment’s sensitivity to heat, pH, oxygen, and other conditions may reduce or lose its function in food products. Due to the sensitivity and instability of microalgae pigment, strategies are needed to protect and retain pigment from reducing their functions. Thirty-two research papers related to the topic published during 2012-2022 were employed in the review. This review focuses on astaxanthin from Haematococcus pluvialis, phycocyanin from Spirulina platensis, and β-Carotene from Dunaliella salina, as widely known microalgae pigments. This paper provides information about the effect of temperature during processing and storage on the stability of the pigments. Strategies to improve pigment stability by encapsulation were also discussed. The study concluded that temperature is one of the essential factors that affects microalgae stability. Furthermore, encapsulation may provide a potential solution to protect and maintain the stability of microalgae pigments.
8
Kohl, Miroslav, Fouzy Alafid, Karolína Boštíková, Anna Krejčová, Stanislav Slang, Dominik Řezníček, Radim Hrdina e Andréa Kalendová. "Preparation and Testing of Anti-Corrosion Properties of New Pigments Containing Structural Units of Melamine and Magnesium Cations (Mg2+)". Coatings 13, n. 11 (19 novembre 2023): 1968. http://dx.doi.org/10.3390/coatings13111968.
Testo completoAbstract (sommario):
This paper deals with the properties and testing of newly prepared organic pigments based on melamine cyanurate containing magnesium or zinc cations depending on their composition and anticorrosive properties in model coatings. Organic pigments based on melamine cyanurate with Mg2+ in the form of a complex differing in the ratio of melamine and cyanurate units were prepared. Furthermore, a pigment based on melamine citrate with magnesium cation Mg2+, a pigment based on melamine citrate with magnesium cation, and a pigment based on melamine cyanurate with zinc cation were prepared. The properties of Mg-containing organic pigments were also compared with those of selected magnesium-containing inorganic oxide-type pigments. The above-synthesized pigments were characterized by inductively coupled plasma-optical emission spectroscopy, elemental analysis, scanning electron microscopy, and X-ray diffraction. In addition, the basic parameters that are indicative of the applicability of the pigments in the binders of anti-corrosion coatings were determined. The anti-corrosive properties of the tested pigments were verified after application to the epoxy-ester resin-based paint binder in three different concentrations: at pigment volume concentrations of 0.10%, 0.25%, and 0.50%. The anticorrosive effectiveness of pigmented organic coatings was verified by cyclic corrosion tests in a salt electrolyte fog (NaCl + (NH4)2SO4) in an atmosphere containing SO2 and by the electrochemical technique of linear polarization. Finally, the effect of the structure of the pigments on the mechanical resistance of the organic coatings was investigated. The results obtained showed that the new organic pigments exhibit anticorrosive properties, and at the same time, differences in performance were found depending on the structure of the pigments tested. Specifically, the results of cyclic corrosion tests and the electrochemical technique of linear polarization clearly demonstrated that synthesized pigments of the organic type based on melamine cyanurate containing magnesium or zinc cations ensure the anti-corrosion efficiency of the tested organic coatings. The highest anti-corrosion efficiency was achieved by the system pigmented with synthesized melamine cyanurate with magnesium cation (C12H16MgN18O6), whose anti-corrosion efficiency was comparable to the anti-corrosion efficiency of the tested inorganic pigment MgFe2O4, which was prepared by high-temperature solid-phase synthesis. In addition, these organic coatings achieved high mechanical resistance after being tested using the most used standardized mechanical tests.
9
P. Nanaware, Jayashri, Shah K.S. e Pathade G.R. "Isolation and Screening of Pigment Producing Bacteria from Soil and Study of Antimicrobial Activity of Pigments". Ecology, Environment and Conservation 30, Suppl.Issue (2024): 16–20. http://dx.doi.org/10.53550/eec.2024.v30i02s.004.
Testo completoAbstract (sommario):
Pigments are colored compounds that play important roles in various biological systems, such as photosynthesis, vision, and signalling. Pigment-producing bacteria are a diverse group of microorganisms that can produce a wide range of pigments with different colors and properties. The present study is aimed to isolate the pigment-producing bacteria from the soil with the antibacterial activity of pigments. Soil samples were collected from nearby Karad city. All eight different pigmented colonies were isolated that produced the pigments like Yellow, Red, Golden Yellow, and Orange and they were designated as YP-I, YP-II, YP-II, GYP-I, GYP-II, RP-I, RP-II, and OP. The isolated organisms were characterized with the help of Bergey’s Manual of Determinative Bacteriology. The pigments were extracted with a solvent like chloroform and the antibacterial activity of the extract was tested against E. coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The extracted pigments had an inhibitory effect on both Gram-positive and Gramnegative bacteria. The pigments of isolates designated as YP-III, GYP-I, GY-II, and RP-II showed the highest antibacterial activity against E. coli.
10
Deveikaite, Goda, e Renata Zvirdauskiene. "Isolation and Characterisation of Pigments from Pigment-producing Microorganisms Isolated from Environment and Their Antibacterial Activity". Rural Sustainability Research 49, n. 344 (1 agosto 2023): 1–7. http://dx.doi.org/10.2478/plua-2023-0001.
Testo completoAbstract (sommario):
Abstract In the food industry, there is always a demand for food products which are colourful, have an attractive appearance, and also have nutritional and health-enhancing properties to attract the attention of consumers. Synthetic pigments are widely used in the global market, however, they can cause many side effects such as hyperallergenicity, carcinogenicity and other toxicological problems. Recent studies have revealed that microorganisms are an abundant source of natural colours that allow the industrial production of safe, environmentally friendly biodegradable pigments. The aim of the work was to isolate pigmented microorganisms from environmental samples, select fermentation conditions, isolate pigments from microorganisms and check their antimicrobial activity. Pigments have been isolated from various sources such as soil, food waste, flour, etc. Growth parameters of pigment-producing microorganisms such as growth temperature, pH, tryptone and NaCl concentration in the medium were optimised to evaluate pigment production. After fermentation, five types of pigments were isolated by cell lysis with an ultrasonic bath and solvent extraction. The antimicrobial activity of the extracted pigments was investigated. During the study, the optimal conditions for the growth of microorganisms were determined: temperature of 30 °C, pH of 7, concentration of 3% tryptone and 6% NaCl in the culture medium. Glycerol was found as an additional carbon source, which had a positive effect on pigments production. The results of the antibacterial effect of the extracted pigments showed that P. aeruginosa was the most sensitive to the effect of the pigments. The pink-red pigment showed the highest antimicrobial activity against the tested pathogenic bacteria.
11
El-Sabbagh, Salwa H., e Nivin M. Ahmed. "Enhancement of styrene-butadiene rubber composites using kaolin covered with metal oxide pigments". Pigment & Resin Technology 44, n. 2 (2 marzo 2015): 57–73. http://dx.doi.org/10.1108/prt-03-2014-0028.
Testo completoAbstract (sommario):
Purpose – This paper aims to express in detail the rheological, morphological and thermal properties of unpigmented and pigmented styrene-butadiene rubber composites with new prepared inorganic pigment based on kaolin covered with a thin layer of calcium and magnesium oxides or mixed oxide of both together. These new pigments combine the properties of both their constituents (kaolin and metal oxides), which are a new trend in inorganic pigments called core-shell pigments. The pigments used for comparison are kaolin (K), CaO/kaolin (CaO/K), MgO/kaolin (MgO/K) and CaO.MgO/kaolin (CaO.MgO/K). Design/methodology/approach – The different pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray diffraction, scanning electron microscopy/energy dispersive X-ray and transmission electron microscopy, while rubber vulcanizates' rheological, morphological, swelling and thermal properties were examined using different standard and instrumental testing and methods. Findings – The study revealed that there is a significant effect of the new prepared pigments on SBR properties, where the optimum pigment loading was 40 phr for CaO/kaolin, while it was 2.5 phr for MgO/kaolin. Studying the effect of different ratios of oxides on kaolin (5, 10 and 20 per cent), different loadings of these pigments ranging between 2.5 and 40 phr were done for each pigment. These modified kaolin or core-shell metal oxide/kaolin pigments imparted new and improved reinforcing properties to SBR vulcanizates. Research limitations/implications – No research limitations were found. Practical implications – Core-shell MgO/kaolin pigments are eco-friendly and can replace other expensive pigments that are usually used as fillers in the rubber industry with less expenses and comparable efficiency. Originality/value – These new pigments are cheap and efficient and can be used in different fields other than rubber.
12
Makino, C. L., e R. L. Dodd. "Multiple visual pigments in a photoreceptor of the salamander retina." Journal of General Physiology 108, n. 1 (1 luglio 1996): 27–34. http://dx.doi.org/10.1085/jgp.108.1.27.
Testo completoAbstract (sommario):
Although a given retina typically contains several visual pigments, each formed from a retinal chromophore bound to a specific opsin protein, single photoreceptor cells have been thought to express only one type of opsin. This design maximizes a cell's sensitivity to a particular wavelength band and facilitates wavelength discrimination in retinas that process color. We report electrophysiological evidence that the ultraviolet-sensitive cone of salamander violates this rule. This cell contains three different functional opsins. The three opsins could combine with the two different chromophores present in salamander retina to form six visual pigments. Whereas rods and other cones of salamander use both chromophores, they appear to express only one type of opsin per cell. In visual pigment absorption spectra, the bandwidth at half-maximal sensitivity increases as the pigment's wavelength maximum decreases. However, the bandwidth of the UV-absorbing pigment deviates from this trend; it is narrow like that of a red-absorbing pigment. In addition, the UV-absorbing pigment has a high apparent photosensitivity when compared with that of red- and blue-absorbing pigments and rhodopsin. These properties suggest that the mechanisms responsible for spectrally tuning visual pigments separate two absorption bands as the wavelength of maximal sensitivity shifts from UV to long wavelengths.
13
Lbova, Liudmila. "Pigment compositions in Siberian early Upper Paleolithic complexes". Journal of the International Union of Prehistoric and Protohistoric Sciences 3, n. 2 (1 settembre 2021): 116–23. http://dx.doi.org/10.62526/lj9ubu.
Testo completoAbstract (sommario):
Cultural assemblages associated with archaic forms of Homo sapiens in Siberia appeared around 40 000 – 50 000 years BP, revealing the evidence of the modern behavioural complex and use of various pigments. Multi-element composition of pigment materials appearing on some Early Upper Palaeolithic objects, which was obtained using SEM-EDX analysis, showed differences in the use of various natural ingredients in the territories of Southern Siberia (as Kara-Bom, Denisova cave (11), Malaya Syya, Khotyk-3, and Kamenka). Microscopic examination and identification of traces using low- and high-power microscopes revealed the presence of pigment and pigment’s composition on the surface of the personal ornamentations, and also as a natural haematite with trace of using. Composite pigments and a wider colour spectrum, including blue and green colours, replace the use of natural pigments such as goethite, hematite, limonite, colorful clays in collections of the early stages of the Upper Palaeolithic. The use of natural pigments in culture has two aspects: utilitarian, for everyday and symbolic. Household use of pigments, especially ochre, is known from ethnographic materials as antiseptic, adhesive material, skin softener, and addition for food.
14
Stenger, Pierre-Louis, Chin-Long Ky, Céline Reisser, Julien Duboisset, Hamadou Dicko, Patrick Durand, Laure Quintric, Serge Planes e Jeremie Vidal-Dupiol. "Molecular Pathways and Pigments Underlying the Colors of the Pearl Oyster Pinctada margaritifera var. cumingii (Linnaeus 1758)". Genes 12, n. 3 (15 marzo 2021): 421. http://dx.doi.org/10.3390/genes12030421.
Testo completoAbstract (sommario):
The shell color of the Mollusca has attracted naturalists and collectors for hundreds of years, while the molecular pathways regulating pigment production and the pigments themselves remain poorly described. In this study, our aim was to identify the main pigments and their molecular pathways in the pearl oyster Pinctada margaritifera—the species displaying the broadest range of colors. Three inner shell colors were investigated—red, yellow, and green. To maximize phenotypic homogeneity, a controlled population approach combined with common garden conditioning was used. Comparative analysis of transcriptomes (RNA-seq) of P. margaritifera with different shell colors revealed the central role of the heme pathway, which is involved in the production of red (uroporphyrin and derivates), yellow (bilirubin), and green (biliverdin and cobalamin forms) pigments. In addition, the Raper–Mason, and purine metabolism pathways were shown to produce yellow pigments (pheomelanin and xanthine) and the black pigment eumelanin. The presence of these pigments in pigmented shell was validated by Raman spectroscopy. This method also highlighted that all the identified pathways and pigments are expressed ubiquitously and that the dominant color of the shell is due to the preferential expression of one pathway compared with another. These pathways could likely be extrapolated to many other organisms presenting broad chromatic variation.
15
Lind, Olle, Mindaugas Mitkus, Peter Olsson e Almut Kelber. "Ultraviolet vision in birds: the importance of transparent eye media". Proceedings of the Royal Society B: Biological Sciences 281, n. 1774 (7 gennaio 2014): 20132209. http://dx.doi.org/10.1098/rspb.2013.2209.
Testo completoAbstract (sommario):
Ultraviolet (UV)-sensitive visual pigments are widespread in the animal kingdom but many animals, for example primates, block UV light from reaching their retina by pigmented lenses. Birds have UV-sensitive (UVS) visual pigments with sensitivity maxima around 360–373 nm (UVS) or 402–426 nm (violet-sensitive, VS). We describe how these pigments are matched by the ocular media transmittance in 38 bird species. Birds with UVS pigments have ocular media that transmit more UV light (wavelength of 50% transmittance, λ T0.5 , 323 nm) than birds with VS pigments ( λ T0.5 , 358 nm). Yet, visual models predict that colour discrimination in bright light is mostly dependent on the visual pigment (UVS or VS) and little on the ocular media. We hypothesize that the precise spectral tuning of the ocular media is mostly relevant for detecting weak UV signals, e.g. in dim hollow-nests of passerines and parrots. The correlation between eye size and UV transparency of the ocular media suggests little or no lens pigmentation. Therefore, only small birds gain the full advantage from shifting pigment sensitivity from VS to UVS. On the other hand, some birds with VS pigments have unexpectedly low UV transmission of the ocular media, probably because of UV blocking lens pigmentation.
16
Hwang, Ga-hyun, Sun Myung Lee e Hye Young Jeong. "Current Status and Raw Material Characteristics of Painted Pigment in used Traditional Dancheong: Focused on the National-designated Wooden Architectural Heritages in Korea". Journal of Conservation Science 38, n. 6 (31 dicembre 2022): 703–19. http://dx.doi.org/10.12654/jcs.2022.38.6.12.
Testo completoAbstract (sommario):
In this study, the composition of traditional Korean Dancheong pigments existing in national-designated wooden architectural heritages was analyzed, and the current status of pigments according to the raw material characteristics used was statistically examined. As for the red pigment, Seokganju, Yeondan, Jusa had a high share, and natural and artificial inorganic pigments had a high usage rate. As for yellow pigments, organic pigments(estimated Deunghwang), Hhwangto, and gold showed a high share. In the case of organic pigments and gold, Yeonbaek was used as a based pigment to increase color development. As for the green pigment, Hayeob, Noerok, Samrok showed a high share. The Hayeob and Neorok are identified as a single raw material, but it can be seen that the Samrok is made by mixing copper oxides such as moolooite and lead-based white raw materials. Blue pigments have a lower share of pigments compared to other colors. As for the blue pigment, Guncheong, Hoecheong, and Seokcheong showed a high market share, and natural and artificial inorganic pigments accounted for the majority. In particular, it is characteristic that the use of expensive pigments such as Seokcheong and Guncheong is concentrated on the Palace Dancheong. White and black pigments have a low share in Dancheong coloring, but the white and black lines play a very important role in the perfection of Dancheong. It can be seen that the white pigment has a high share of Baekto(white clay) and Yeonbaek, and is used not only for coloring but also as a based pigment for color pigments. Most of the black pigment is made up of more than 95% organic raw material containing carbon as its main component, and it shows various aspects depending on the lower pigment layer. Through this, it was confirmed based on on-site analysis data of wooden architectural heritage that the color pigment used in Dancheong had a higher percentage of use of inorganic pigments and that the use rate of natural inorganic pigments was higher than that of artificial synthetic pigments in inorganic pigments.
17
Пушкарьова, К. К., e Л. В. Терещенко. "ASSESSMENT OF THE INFLUENCE OF INORGANIC PIGMENTS ON THE TECHNOLOGICAL PROPERTIES OF DECORATIVE CEMENTS". Building production, n. 76 (18 settembre 2024): 37. http://dx.doi.org/10.36750/2524-2555.76.37-42.
Testo completoAbstract (sommario):
The article presents the results of research on the influence of inorganic pigments on the technological properties of decorative cements. It has been established that regardless of the color of the pigment, with an increase in its quantity in the system, we get a more saturated and bright color of cement stone, but at the same time there is a negative effect of pigments and technological and physical and mechanical properties of artificial stone. The research was conducted on cement systems based on white Portland cement without additives and on cement systems based on white Portland cement modified with polycarboxylate superplasticizer. An increase in the amount of pigment, regardless of its color, leads to an increase in the water consumption of the cement system, however, when a superplasticizer is introduced, the effect of the pigment is not so significant. At the same time, the introduction of a superplasticizer reduces the water consumption of white cement without the introduction of pigments by an average of 37-40%. In addition, it was established that the introduction of pigments affects the hardening time of cement systems. At the same time, pigments, depending on their color and dosage, have different effects on both the start and end of aging. With an increase in the pigment content in a cement system without a plasticizer, the time of the onset of hardening increases, and the introduction of a permanent pigment has the greatest effect on the end of hardening of such a system. The introduction of pigments into plasticized cement systems increases both the start and end time of hardening. As the number of pigments of all colors increases, the strength of the samples decreases. At the same time, the red pigment leads to the greatest decline in strength at all stages of hardening. The decrease in strength can be explained by the increased water consumption, and, as a result, the increased porosity of pigmented samples compared to samples without the introduction of pigments. Further research aimed at finding additives that will reduce the negative impact of inorganic pigments on the processes of hydration and hardening of the cement system, and therefore on the durability of the obtained artificial stone, will be relevant. At the same time, it is important to preserve the intensity of the color and the absence of sediment formation.
18
Ramesh, Vinithkumar, Kirubagaran, Venil e Dufossé. "Multifaceted Applications of Microbial Pigments: Current Knowledge, Challenges and Future Directions for Public Health Implications". Microorganisms 7, n. 7 (28 giugno 2019): 186. http://dx.doi.org/10.3390/microorganisms7070186.
Testo completoAbstract (sommario):
Microbial oddities such as versatile pigments are gaining more attention in current research due to their widely perceived applications as natural food colorants, textiles, antimicrobial activities, and cytotoxic activities. This indicates that the future generation will depend on microbial pigments over synthetic colorants for sustainable livelihood. Although several reviews have detailed the comprehensive applications of microbial pigments extensively, knowledge on several aspects of pigmented microbes is apparently missing and not properly reviewed anywhere. Thus, this review has been made to provide overall knowledge on biodiversity, distribution, pathogenicity, and ecological and industrial applications of microbial pigments as well as their challenges and future directions for food, industrial, and biomedical applications. Meticulously, this compendious review treatise on the pigments from bacteria, fungi, yeasts, and microalgae includes reports from the 1970s to 2018. A total of 261 pigment compounds produced by about 500 different microbial species are included, and their bioactive nature is described.
19
Zhang, Yong, Xuening Fei, Lu Yu, Lingyun Cao e Baolian Zhang. "Preparation and characterisation of silica supported organic hybrid pigments". Pigment & Resin Technology 43, n. 6 (3 novembre 2014): 325–31. http://dx.doi.org/10.1108/prt-10-2013-0087.
Testo completoAbstract (sommario):
Purpose The purpose of the work reported in this paper is to prepare hybrid pigments fabricated by depositing pigment yellow 12 (PY12) on the surface of silica gel to improve the application performance of the resulting pigments. The particle size distribution, optical properties, thermal stability, water dispersibility and flowability of the pigments with and without silica gel modification were studied. Design/methodology/approach The hybrid pigments were synthesised with different amount of silica gel. The modified pigments were characterised by Fourier transforms infrared spectroscopy, X-ray diffraction, thermal analysis, scanning electron microscopy and transmission electron microscopy. Findings The particle size distribution of the modified pigments was found to have been altered significantly. This can be explained by the interaction between pigments and silica gel, which prevented self-aggregation of pigment particles and hence improved the properties of pigments. Research limitations/implications Only silica supports and pigment yellow 12 were evaluated. Other pigments could also be studied. Practical implications Modification of pigment particles with smaller particle size can increase the efficiency of the modified pigment, in terms of colour shade and tinting strength, due to better particle size distribution. Originality/value The paper demonstrates that inorganic core can prevent self-aggregation of pigment particles, and the application properties of such pigment depend on the resulting degree of dispersion of pigment particles.
20
B. N., Narendrababu, e Shishupala S. "Bioprospecting of Talaromyces ruber pigments for antimicrobials". Biomedicine 43, n. 3 (1 luglio 2023): 963–71. http://dx.doi.org/10.51248/.v43i3.2667.
Testo completoAbstract (sommario):
Introduction and Aim: Metabolic flexibility of fungi is unique among organisms. Fungi can produce various pigments of industrial importance. Potential of Talaromyces ruber for beneficial pigments needs to be explored. Hence, the present study aims at the detection of pigments from T. ruber and determining their antimicrobial properties. Materials and Methods: A soil isolate of T. ruber was tested for pigment production. Cellular and secretory pigments were extracted. They were separated by thin-layer chromatography (TLC) and detected by UV-Visible spectrophotometry. The antibacterial activities of crude pigments were tested by disc diffusion method. The antifungal activity was detected by disc diffusion method, conidial germination inhibition assay and bioautography methods. Results: The results showed that cellular metabolites yielded seven pigment fractions and secretory metabolites yielded five different pigment fractions in TLC. In UV-Visible spectrometry, the absorption range of visible light with 370 to 412 nm detected yellow pigments and absorption of 500 to 520 nm detected red pigments. Crude cellular and secretory pigment fractions showed inhibition activity only on Bacillus subtilis. The antifungal activity of both crude cellular and secretory pigments was observed against Candida albicans and Cryptococcus sp. The secretory crude pigment showed conidial germination inhibition only against Alternaria tenuissima. In bioautography, the cellular and secretory crude pigments showed an inhibition zone for Cladosporium oxysporum. Additionally, secretory crude pigment showed similar activity against Curvularia lunata. Interestingly, the variations in the antifungals between cellular and secretory pigment fractions are also evident. Production of antimicrobial compounds from T. ruber was established after the detection of pigment fractions. Conclusion: Potential of T. ruber to produce yellow and red pigments was realized. Antimicrobial pigments from T. ruber were detected providing scope to develop for industrial scale. These pigments may be used in pharmaceutical and nutritional industries.
21
Narendrababu, B. N., e S. Shishupala. "Biological Activities of Pigments from Aspergillus nidulans". International Journal of Current Microbiology and Applied Sciences 12, n. 6 (10 giugno 2023): 62–75. http://dx.doi.org/10.20546/ijcmas.2023.1206.009.
Testo completoAbstract (sommario):
The biological activity shown by fungal pigments is of significance for broadening their applications. In the current research, both cellular and secretory pigments produced by Aspergillus nidulans were separated by thin-layer chromatography (TLC) and detected by UV-Visible spectroscopy. The fractions were examined for their biological functions in terms of antimicrobial and antioxidant activities. The findings revealed that the crude cellular pigments had absorption maxima at 458 nm and 521 nm, corresponding to orange and red pigments respectively. The crude secretory pigments showed absorption maxima at 464 nm, representing orange pigments. In TLC, eight pigment fractions were separated in cellular pigment extract whereas nine pigment fractions were observed in secretory pigment extract. The crude cellular pigment extract was exclusively effective against Bacillus subtilis. The crude secretory pigment extract presented antibacterial activity on B. subtilis and Staphylococcus aureus. The crude cellular pigment extract had slight inhibition of Candida albicans whereas the crude secretory pigment extract showed inhibition against both Candida albicans and Cryptococcus sp. In the bioautography, the crude secretory pigment displayed inhibition activity on all the tested fungi whereas the crude cellular pigment extract revealed inhibition activity only against Curvularia lunata. Both cellular and secretory pigments showed antioxidant activity in a dose-dependent manner. The potential pigments with biological activity are promising candidates in the food and pharmaceutical industry.
22
Huang, Luwen, e Liping Zhu. "Research Progress of Natural Edible Blue Pigment". Academic Journal of Science and Technology 2, n. 3 (26 agosto 2022): 20–25. http://dx.doi.org/10.54097/ajst.v2i3.1438.
Testo completoAbstract (sommario):
Natural edible blue pigment is a scarce pigment among natural pigments, mainly derived from animal and plant tissues, microbial fermentation metabolites. Among the plant natural blue pigments, the ones that account for the widest market of edible natural blue pigments are algal blue pigment and gardenia blue pigment. The sources of microbial natural blue pigment include some fungi and bacteria in addition to microalgae, mainly focusing on the study of Streptomyces, Pseudomonas, Pseudoalteromonas, purple non-sulfur bacteria, Dourollerella, and sprouting short-stalked mold. The natural blue pigment is unstable, so it is of far-reaching significance to improve the extraction process, especially the research on the isolation and purification of blue pigment produced by microbial fermentation. High-speed frozen centrifugation, solid-phase extraction, high performance liquid chromatography, nuclear magnetic resonance spectroscopy, mass spectrometry and other methods are commonly used for the separation and purification of natural blue pigments and analytical identification. Some natural blue pigments have antioxidant, antitumor, hypolipidemic, hypoglycemic, anti-inflammatory, anti-cancer, immunomodulatory activities, etc. There will be a broad development prospect for the future research of natural blue pigments.
23
Zhang, Chan, Qing Sun, Le Yang, Arzugul Ablimit, Huijun Dong, Haijiao Wang, Congcong Wang e Chengtao Wang. "Mutation Breeding of Monascus to Produce a High Yield of Orange Pigment and Low Citrinin Content Using the ARTP Method". Journal of Fungi 10, n. 8 (5 agosto 2024): 553. http://dx.doi.org/10.3390/jof10080553.
Testo completoAbstract (sommario):
Monascus is a filamentous fungus with a long history of application in China, which can produce a variety of secondary metabolites, including Monascus red pigments, Monascus orange pigments, Monascus yellow pigments, and citrinin. There is widespread attention being paid to natural pigments because of their safety. Among the many natural pigments, orange pigment has a wide range of applications because of its unique color, but current production levels in the orange pigment industry are limited to a certain extent due to the insufficiently wide range of sources and low production. In this study, the ARTP mutation was used to obtain a strain with high-yield orange pigment and low citrinin. The strain RS7 was obtained through two-step mutagenesis, and all three pigments were improved to different degrees. The color value of orange pigment was elevated from the original 108 U/mL to 180 U/mL, an increase of 66.7% compared to the original strain, and the citrinin content was reduced by 69%. The result of microscopic morphology showed that RS7 has more wrinkles and is more convex than the R1 strain, but there was little change between the two strains. Therefore, the ARTP mutation influenced the growth and the biosynthesis of pigments in Monascus. In addition, the conditions of ultrasonic extraction of Monascus pigments were optimized using the response surface, and the separation of pigments was achieved with the method of thin-layer chromatography. Pigment stability results showed that the temperature had no significant effect on orange pigment, while tea polyphenol could improve its stability. This study generated a strain with high-yielding orange pigment and could lay a foundation for the future application of Monascus orange pigment in the food industry.
24
Tsiailanis, Antonis D., Chrysanthi Pateraki, Mary Kyriazou, Christos M. Chatzigiannis, Maria Chatziathanasiadou, Nikolaos Parisis, Ioanna Mandala, Andreas G. Tzakos e Apostolis Koutinas. "Chemical Profiling, Bioactivity Evaluation and the Discovery of a Novel Biopigment Produced by Penicillium purpurogenum CBS 113139". Molecules 27, n. 1 (23 dicembre 2021): 69. http://dx.doi.org/10.3390/molecules27010069.
Testo completoAbstract (sommario):
Biobased pigments are environmentally friendly alternatives to synthetic variants with an increased market demand. Production of pigments via fermentation is a promising process, yet optimization of the production yield and rate is crucial. Herein, we evaluated the potential of Penicillium purpurogenum to produce biobased pigments. Optimum sugar concentration was 30 g/L and optimum C:N ratio was 36:1 resulting in the production of 4.1–4.5 AU (namely Pigment Complex A). Supplementation with ammonium nitrate resulted in the production of 4.1–4.9 AU (namely Pigment Complex B). Pigments showed excellent pH stability. The major biopigments in Pigment Complex A were N-threonyl-rubropunctamin or the acid form of PP-R (red pigment), N-GABA-PP-V (violet pigment), PP-O (orange pigment) and monascorubrin. In Pigment Complex B, a novel biopigment annotated as N-GLA-PP-V was identified. Its basic structure contains a polyketide azaphilone with the same carboxyl-monascorubramine base structure as PP-V (violet pigment) and γ-carboxyglutamic acid (GLA). The pigments were not cytotoxic up to 250 μg/mL.
25
Yadav, Vivek Kumar. "Comparative Growth Rate of Cyanobacteria from “Usar” Soil (saline/alkaline soils) with Respect to Pigments". Indian Journal of Pure & Applied Biosciences 9, n. 4 (30 agosto 2021): 129–35. http://dx.doi.org/10.18782/2582-2845.8759.
Testo completoAbstract (sommario):
The pigment content in Blue-green algae is a specific feature of each species. The pigment variation is specific features among microalgae. The paper aim to analyze cyanobacterial extracts of different Usar soil of Azamgarh and Varanasi, Uttar Pradesh. The main object here is the importance of the blue green algae especially because of the pigments present in this class of algae. Pigments from natural sources are gaining more importance mainly due to health and environmental issues. Algae contain a wide range of pigments. Three major classes of pigments are chlorophylls, carotenoids (carotenes and xanthophylls) and phycobilins (Phycocyanin and phycoerythrin). Our present study investigates the efficiency for phycobiliprotein pigment production from four different cyanobacteria Hapalosiphon sp., Phormidium sp., Anabaena sp. and Nostoc sp. The harvested and dried biomass was subjected to extract pigments using different solvents. Thin Layer Chromatography was performed from extracted pigments using Acetone as extraction solvents. And running solvent especially for phycocyanin pigment was optimized and concluded that Petroleum ether and Acetone in the ratio of 7:3. This paper presents the information about the natural pigments of cyanobacteria and how they can be extracted and identified using different procedures and spectrophotometry. It emphasizes that the principal algal pigments are Phycobilins, Chlorophylls and Carotenoids.
26
Gorgieva, Selestina, Natalija Virant e Alenka Ojstršek. "Complementary Assessment of Commercial Photoluminescent Pigments Printed on Cotton Fabric". Polymers 11, n. 7 (20 luglio 2019): 1216. http://dx.doi.org/10.3390/polym11071216.
Testo completoAbstract (sommario):
The presented study focuses on photoluminescent pigments applied on cotton fabric by a screen-printed procedure using polydimethylsiloxane (PDMS) as a binder. Microscopic data depicts irregular shapes and relatively wide size distribution (3–80 µm) of pigments. Regarding composition, the Energy-Dispersive X-ray (EDX) and Fourier Transform Infrared (FTIR) spectroscopy data complement findings suggesting the presence of Eu-doped strontium aluminate in the yellow-green, calcium aluminate in the violet pigment, and metal oxides in the blue pigment. The optical properties of pigment-enriched PDMS-coated cotton fabric were assessed and reflectance intensity was found to be concentration-dependent only in the blue pigment. The luminescence decay data show that luminescence intensity decreased with the reduction of pigment concentration in the following order, yellow-green > blue > violet pigments. Relying on absorption and emission data of powdered pigments, the confocal microscopy enables visualization of the pigments’ distribution within a 3D image projection. This identifies the most homogeneous distribution in the case of the blue pigment, as well as the presence of a continuous fluorescing signal in the z projection when 5% pigment was used. This was, for the first time, presented as a powerful tool for non-destructive visualization of photoluminescent pigments’ spatial distribution when printed on textile (cotton) fabric. Finally, the photoluminescent PDMS coating demonstrates high washing and abrasion resistance, contributing to overall functionality of printed cotton fabrics when commercial types of pigments are applied.
27
Sarker, Umakanta, Tofazzal Islam, Golam Rabbani e Shinya Oba. "Antioxidant leaf pigments and variability in vegetable amaranth". Genetika 50, n. 1 (2018): 209–20. http://dx.doi.org/10.2298/gensr1801209s.
Testo completoAbstract (sommario):
Twenty-three vegetable amaranth genotypes were evaluated for variability, interrelationships among antioxidant leaf pigments and foliage yield. Five genotypes found to be a rich source of antioxidant leaf pigments and might be directly selected as antioxidant leaf pigments enriched high yielding varieties. Two genotypes had high content of antioxidant leaf pigments with low yield might be used as donor parents for antioxidant leaf pigments genes to develop transgressive segregant or pigment enriched transgenic vegetable amaranth varieties. The insignificant negative genotypic correlation was observed between total carotene versus all antioxidant leaf pigments, ascorbic acid versus all antioxidant leaf pigments and foliage yield versus rest of all traits. Improvement of vegetable amaranth regarding carotene and ascorbic acid might be possible without compromising yield loss. On the other hand, most of the interrelationships among antioxidant leaf pigments traits indicated that improving of one antioxidant leaf pigment significantly improved the other antioxidant leaf pigments.
28
Niederer, Markus, Urs Hauri, Lydia Kroll e Christopher Hohl. "Identification of organic pigments in tattoo inks and permanent make-ups using MALDI-TOF mass spectrometry". F1000Research 6 (21 novembre 2017): 2034. http://dx.doi.org/10.12688/f1000research.13035.1.
Testo completoAbstract (sommario):
Nowadays, about 12% of the European and 20% of the US population are tattooed. Rising concerns regarding consumer safety, led to legal restrictions on tattoo inks and permanent make-up (PMU) inks. Restrictions also include bans on certain hazardous colourants. Both ink types use organic pigments for colour-giving, plus inorganic pigments for white and black and colour tones. Pigments are only sparingly soluble in common solvents and occur as suspended particles in the ink matrix. Their detection and identification therefore pose a major challenge for laboratories involved in monitoring the legal compliance of tattoo inks and PMUs. We overcame this challenge by developing a matrix-assisted laser desorption ionisation time-of-flight mass spectrometry method, which included an easy sample clean up. The method proved to be capable of detecting and identifying organic pigments in almost all of the tested ink samples. Method validation and routine deployment during market surveys showed the method to be fit for purpose. Pigment screening of 396 tattoo inks and 55 PMUs taken from the Swiss market between 2009 and 2017 lead to the following conclusions: Pigment variety is much greater in tattoo inks (18) than in PMUs (10); four prohibited pigments (Pigment Green 7, Pigment Red 122, Pigment Violet 19 and 23) were found in both ink types; for PMUs, these four pigments made up 12% of the pigment findings, compared to 32% for tattoo inks. Therefore, legal compliance of PMUs was at a higher level. A comparison of pigments found with those declared on tattoo ink labels clearly showed that banned pigments are rarely declared, but rather masked by listing not present legal pigments and label forging; therefore, highlighting the urgency of widespread market controls.
29
Niederer, Markus, Urs Hauri, Lydia Kroll e Christopher Hohl. "Identification of organic pigments in tattoo inks and permanent make-up using laser desorption ionisation mass spectrometry". F1000Research 6 (8 gennaio 2018): 2034. http://dx.doi.org/10.12688/f1000research.13035.2.
Testo completoAbstract (sommario):
Nowadays, about 12% of the European and 20% of the US population are tattooed. Rising concerns regarding consumer safety, led to legal restrictions on tattoo and permanent make-up (PMU) inks. Restrictions also include bans on certain colourants. Both ink types use organic pigments for colour-giving, plus inorganic pigments for white and black and colour tones. Pigments are only sparingly soluble in common solvents and occur as suspended particles in the ink matrix. Their detection and identification therefore pose a major challenge for laboratories involved in monitoring the legal compliance of tattoo inks and PMU. We overcame this challenge by developing a direct laser desorption ionisation time-of-flight mass spectrometry method, which included an easy sample clean up. The method proved to be capable of detecting and identifying organic pigments in almost all of the tested ink samples. Method validation and routine deployment during market surveys showed the method to be fit for purpose. Pigment screening of 396 tattoo inks and 55 PMU taken from the Swiss market between 2009 and 2017 lead to the following conclusions: Pigment variety is much greater in tattoo inks (18) than in PMU (10); four prohibited pigments (Pigment Green 7, Pigment Red 122, Pigment Violet 19 and 23) were found in both ink types; for PMU, these four pigments made up 12% of the pigment findings, compared to 32% for tattoo inks. Therefore, legal compliance of PMU was at a higher level. A comparison of pigments found with those declared on tattoo ink labels clearly showed that banned pigments are rarely declared, but rather masked by listing non present legal pigments and label forging; therefore, highlighting the urgency of widespread market controls.
30
Hashimoto, Kimiko, Yoko Saikawa e Masaya Nakata. "Studies on the red sweat of the Hippopotamus amphibius". Pure and Applied Chemistry 79, n. 4 (1 gennaio 2007): 507–17. http://dx.doi.org/10.1351/pac200779040507.
Testo completoAbstract (sommario):
The secretion from the hippopotamus' skin changes its color from colorless to red, and then brown by polymerization of its pigments. The responsible pigments for the coloring reaction were isolated and denoted as hipposudoric acid (the red pigment) and norhipposudoric acid (the orange pigment). The syntheses of these pigments and the related derivatives were performed, and the latter were of use to elucidate the structures of these pigments including their tautomeric structures in aprotic and protic solvents. These pigments were estimated to be medicines for the hippopotamus, having the effect of both protecting the skin from sunburn and preventing infection by some microbes.
31
MATHER, ROBERT R. "The Effect of Crystal Properties on the Manufacture and Application Performance of Copper Phthalocyanine Pigments". Journal of Porphyrins and Phthalocyanines 03, n. 07 (ottobre 1999): 643–46. http://dx.doi.org/10.1002/(sici)1099-1409(199908/10)3:6/7<643::aid-jpp187>3.0.co;2-v.
Testo completoAbstract (sommario):
Copper phthalocyanines are commercially important organic pigments for blue shades of colour. They are dispersed by mechanical means as tiny molecular crystals (of dimensions 0.02—0.5 μm) into a wide range of commercial media to form products such as printing inks, paints and coloured plastics. Many important technological properties of copper phthalocyanine pigments, including colour strength and dispersion performance, depend on the physical properties of their crystals, notably crystal lattice type, crystal size and crystal shape. The roles which these crystal properties play in determining a copper phthalocyanine pigment's technological performance are briefly reviewed. The reduction of crystal aggregation during the manufacture of a copper phthalocyanine pigment and the control of flocculation in an application medium are also highlighted.
32
Partridge, J. C., S. N. Archer e J. Vanoostrum. "Single and multiple visual pigments in deep-sea fishes". Journal of the Marine Biological Association of the United Kingdom 72, n. 1 (febbraio 1992): 113–30. http://dx.doi.org/10.1017/s0025315400048827.
Testo completoAbstract (sommario):
The visual pigments in the retinal rods of 17 species of deep-sea fish were examined by microspectrophotometry or visual pigment extract spectrophotometry. In 15 species single visual pigments were found with peak sensitivities between 470 and 490 nm, typical of deep-sea fishes. However, in one species, Stylephorons cordatus, two visual pigments were found with λ values at 470 and 481 nm. In another species, Scopelarchus analis, three visual pigments were found with mean λ values of 444, 479 and 505 nm. The short-wave pigment of this species was found both in main and accessory retinae. It was present both in single rods and in outer segments which had the most long-wave sensitive pigment in their distal parts. It is argued that these two-pigment rods are in the process of changing their visual pigment from a ‘juvenile’ VP505 pigment to an ‘adult’ VP444 pigment. The VP479 was found only as a single pigment in rods in the accessory retina.
33
Koli, Sunil H., Rahul K. Suryawanshi, Bhavana V. Mohite e Satish V. Patil. "Prospective of Monascus Pigments as an Additive to Commercial Sunscreens". Natural Product Communications 14, n. 12 (1 dicembre 2019): 1934578X1989409. http://dx.doi.org/10.1177/1934578x19894095.
Testo completoAbstract (sommario):
Red and yellow pigments from Monascus purpureus (NMCC-PF01) were evaluated to enhance sun protection factor (SPF) of commercial sunscreens and Aloe vera extract. The extracted Monascus pigments contain rubropunctamine (red pigment) and the mixture of monascin and ankaflavin (yellow pigment) as major components. Antioxidant activity and in-vitro safety of the pigments were assessed by ferric reduction potential and DPPH radical scavenging assays, human keratinocytes (HaCaT), and erythrocytes (RBCs) cytotoxicity assay, respectively. In results, SPF of commercial sunscreens showed an increase of 36.5% with red pigment compared to the 13% increase by yellow pigment. The in-vitro studies showed 67.6% ferric reducing potential and 27% DPPH radical scavenging activity, neither cytotoxic effect against human keratinocytes nor haemolytic activity. These results confirmed the safe nature of the Monascus pigments; however, in-vivo studies merit further research. In conclusion, screened pigments from Monascus purpureus may act as potential candidates to increase SPF of commercial sunscreen naturally.
34
Almurshidi, Badria H., R. C. Van Court, Sarath M. Vega Gutierrez, Stacey Harper, Bryan Harper e Seri C. Robinson. "Preliminary Examination of the Toxicity of Spalting Fungal Pigments: A Comparison between Extraction Methods". Journal of Fungi 7, n. 2 (22 febbraio 2021): 155. http://dx.doi.org/10.3390/jof7020155.
Testo completoAbstract (sommario):
Spalting fungal pigments have shown potential in technologies ranging from green energy generation to natural colorants. However, their unknown toxicity has been a barrier to industrial adoption. In order to gain an understanding of the safety of the pigments, zebrafish embryos were exposed to multiple forms of liquid media and solvent-extracted pigments with concentrations of purified pigment ranging from 0 to 50 mM from Chlorociboria aeruginosa, Chlorociboria aeruginascens, and Scytalidium cuboideum. Purified xylindein from Chlorociboria sp. did not show toxicity at any tested concentration, while the red pigment dramada from S. cuboideum was only associated with significant toxicity above 23.2 uM. However, liquid cultures and pigment extracted into dichloromethane (DCM) showed toxicity, suggesting the co-production of bioactive secondary metabolites. Future research on purification and the bioavailability of the red dramada pigment will be important to identify appropriate use; however, purified forms of the blue-green pigment xylindein are likely safe for use across industries. This opens the door to the adoption of green technologies based on these pigments, with potential to replace synthetic colorants and less stable natural pigments.
35
Ati, Neltji Herlina, Puji Rahayu, Soenarto Notosoedarmo e Leenawaty Limantara. "THE COMPOSITION AND THE CONTENT OF PIGMENTS FROM SOME DYEING PLANT FOR IKAT WEAVING IN TIMORRESE REGENCY, EAST NUSA TENGGARA". Indonesian Journal of Chemistry 6, n. 3 (15 giugno 2010): 325–31. http://dx.doi.org/10.22146/ijc.21741.
Testo completoAbstract (sommario):
Ikat weaving is one of traditional-home industry using plant pigments as a dye which have not been known for their pigments composition. So, the research was carried out to know the composition and the content of pigments in young leaf teak, noni root, turmeric tuber, casuarine bark and betel-nut root. The result showed that pigment composition in young leaf teak consisted of β-carotene, pheophytine, phelargonydine 3-glucosyde, phelargonydine 3,7-diglucosyde, chlorophyllide and two other pigments that have not been identified. Most of the pigments composition in betel-nut root have not been identified, but one of them was condensed tanin. Noni root had pigment composition which consisted of hydrolised tanin, flavonoid and morindon. Pigment composition in turmeric tuber were curcumin, demethoxy curcumin and bis-demethoxy curcumin. Whereas casuarine bark had pigment composition which consisted of delphynidine, cyanydine and phelargonydine. The highest pigment concentration in young leaf teak, betel-nut root, noni root, tumeric tuber and casuarine bark was pheophytine, tanin condensation, morindon, curcumin and cyanidine, respectively. Keywords: ikat weaving, chlorophyll, carotenoid, anthocyanin
36
Afifah Mursyida Zaujan, Nur, Mohamad Zohdi Othman, Fatin Najihah Mohd Lutfi, Kamarul Rahim Kamarudin, Hanina Mohd Noor e Maryam Mohamed Rehan. "IDENTIFICATION AND CHARACTERIZATION OF PIGMENTED BACTERIA ISOLATED FROM MALAYSIAN SEAWATER". International Journal of Students' Research in Technology & Management 7, n. 4 (30 dicembre 2019): 01–08. http://dx.doi.org/10.18510/ijsrtm.2019.741.
Testo completoAbstract (sommario):
Purpose of study: Bacteria can naturally produce pigments that can be useful for various applications as they possess antimicrobial metabolites among other numerous benefits towards the human health. This study was carried out to identify the species of marine bacterial isolates PMA, PM3C1 and PM5C1 exhibiting yellow, orange and green colors respectively.
Methodology: The current study is using Polymerase Chain Reaction (PCR) amplification and sequence analysis of their 16S rRNA gene. The stability of pigments extracted from the bacterial samples was also analyzed against different temperature and light conditions.
Main Findings: Sequence alignment using BLAST revealed that the yellow, orange, and green-pigmented bacteria have 84% similarity with Staphylococcus aureus, 85% similarity with Exiguobacterium profundum and 95% similarity with Pseudomonas aeruginosa respectively. The green pigment showed major changes in color following exposure to sunlight and fluorescent light, and when incubated at 24°C and 50°C. Exposure to direct sunlight also results in the reduction of color for the yellow and orange extracts, while no effect was observed for both pigments under fluorescent light. Incubation at 50°C results in the reduction of the orange color, while the yellow pigment was observed to be unaffected suggesting its stability at high temperature.
Implications: Natural pigments production can provide many advantages including reduction of pollution generation, ease of disposal and other benefits to the human health.
37
Valencia, Ricardo, Ivone Giffard-Mena, Ricardo Cruz-López, Ernesto García-Mendoza e José Luis Stephano-Hornedo. "Growth Profiles, Nutrient composition and Pigments Analysis of Dunaliella salina strain San Quintin". CICIMAR Oceánides 33, n. 2 (13 agosto 2018): 1. http://dx.doi.org/10.37543/oceanides.v33i2.212.
Testo completoAbstract (sommario):
Some microalgae are recognized for producing pigments and other metabolites with biotechnological importance, particularly, <i>Dunaliella salina</i> is a remarkable one. These kind of compounds are used as food and have a great industrial potential. The pigment industry comprises a millionaire market value, being β-carotene one of the most profitable one. In this study we describe the morphology, molecular identification, growth dynamics, proximal composition, nutrients and pigment content of a recently isolated <i>Dunaliella salina</i> strain (SQ) under different salinity/light conditions, in order to highlight its remarkable properties for biotech/biomed industry. <i>D. salina</i> SQ reached the highest densities (1.07-1.25 cell mL-1 x106) at low salinities (100-500 mM NaCl) under continuous light regimen (24:0 h Light:Dark). Neoxanthin (Neo) and violaxanthin (Viol) were the most abundant pigments when exposed to 500 mM NaCl (18:6 h Light:Dark). Furthermore, this peculiar strain produces other compounds with high industrial value.Perfiles de crecimiento, composición de nutrientes y análisis de pigmentos de <i>Dunaliella salina</i> cepa San Quintín Algunas microalgas son reconocidas por producir pigmentos y otros metabolitos con importancia biotecnológica, en particular, <i>Dunaliella salina</i> es una de las más notables. Este tipo de compuestos se usan como alimento y tienen potencial industrial. La industria del pigmento tiene un valor de mercado millonario, siendo el β-caroteno uno de los más rentables. En este estudio se describe la morfología, la dinámica de crecimiento, composición proximal, composición de nutrientes y contenido de pigmentos de una cepa de <i>Dunaliella salina</i> (SQ) recientemente aislada. La identificación de la especie se corroboró mediante técnicas moleculares. Se cultivó a <i>D. salina</i> bajo diferentes condiciones de salinidad y luz, con el objetivo de resaltar sus propiedades para la industria biotecnológica y biomédica. <i>D. salina</i> SQ alcanzó las densidades más altas (1.07-1.25 células mL-1 x106) a salinidades bajas (NaCl 100 y 500 mM) en un régimen de luz continua. La neoxantina (Neo) y la violaxantina (Viol) fueron los pigmentos más abundantes en 500 mM NaCl y un ciclo de luz: oscuridad 18: 6 h. Además, esta peculiar cepa produce otros compuestos con alto valor industrial.
38
Pugacheva, Tatyana A., Georgiy V. Malkov, Alexander A. Ilyin, Eugene A. Indeikin e Vladimir G. Kurbatov. "Core/Shell Pigments with Polyaniline Shell: Optical and Physical–Technical Properties". Polymers 14, n. 10 (13 maggio 2022): 2005. http://dx.doi.org/10.3390/polym14102005.
Testo completoAbstract (sommario):
Core/shell pigments allow for the combination of the active anti-corrosion effect of the shell and the barrier effect of the core. This makes it possible to obtain anti-corrosion pigments, with a high—protective effect and low toxicity. Thus, the need for a comprehensive study of the properties of these pigments grows more urgent, before their application to paints and varnishes. The hiding power of core/shell pigments comes close to the one of pure polyaniline (PANi), when the PANi content in the pigment reaches 50 wt.%, with sulfuric and phosphoric acids used as dopants. This paper, also, shows that the blackness value of core/shell pigments with 10 wt.% PANi is around 35 and constant; for pure PANi, their blackness value is 40. When PANi content is 5 wt.%, kaolin-based pigment shows the lowest blackness, which happens due to a generally higher whiteness of kaolin. However, when the PANi content surpasses 10 wt.%, there seems to be no influence on the blackness of the core/shell pigments. The core/shell pigment with a 20 wt.% PANi is, optically, identical to a black-iron-oxide pigment. An increase in the PANi content of the core/shell pigment leads to an increase in the oil absorption of the samples. It was found that the dispersion process would be the most energy efficient for core/shell pigments, containing kaolin and talc as a core.
39
Marques, Rayana Pires, Clarissa Soares Freire, Hugo Henrique Costa do Nascimento e Rejane Jurema Mansur Custósio Nogueira. "Relações Hídricas e Produção de Pigmentos Fostossinteticos em Mudas de Eugenia Uniflora l. Sob Condições de Salinidade (Water Relations and Production of Pigments in Seedlings Photosynthetic Eugenia Uniflora l. Under Salinity Conditions)". Revista Brasileira de Geografia Física 4, n. 3 (24 settembre 2011): 497. http://dx.doi.org/10.26848/rbgf.v4i3.232729.
Testo completoAbstract (sommario):
Esta pesquisa objetivou avaliar os efeitos da salinidade nas relacoes hidricas e teor de pigmentos fotossintetizantes em mudas de pitangueira. Para tanto, foi desenvolvido um experimento em casa de vegetacao do Laboratorio de Fisiologia Vegetal, pertencente ao Departamento de Biologia da UFRPE, no periodo de dezembro de 2010 a abril de 2011. O delineamento experimental utilizado foi o inteiramente casualizado com quatro tratamentos salinos: 0 (controle), 30, 60 e 90 mM de NaCl, e com cinco repeticoes por tratamento. Aos 35 e 95 DAD (dias apos diferenciacao) decorreram as analises fisiologicas. Foram mensurados o potencial hidrico foliar e o teor relativo de agua em dois horarios: antemanha (4h) e meiodia (12h) e os pigmentos fotossintetizantes. A alta demanda evaporativa (12 horas) ocasionou reducoes significativas para o potencial hidrico foliar e teor relativo de agua na pitangueira. Nestes horarios tambem ocorreram diferencas nos pigmentos, entre os niveis de salinidade estudados. Os resultados indicam que a imposicao da salinidade propiciou reducoes no status hidrico das plantas. Em relacao aos pigmentos fotossinteticos, o estresse em curto prazo gerou sua diminuicao, porem em longo prazo, gerou aumento dos mesmos. A variavel fotossintetica estudada mais afetada foram os carotenoides. Palavras-chave: Potencial Hidrico Foliar, Teor Relativo de Agua, estresse salino, pigmentos fotossinteticos Water Relations and Production of Pigments in Seedlings Photosynthetic Eugenia Uniflora l. Under Salinity Conditions ABSTRACT This research had as objective evaluate the effects of salinity in the hydric relations and photosynthetic pigments amount in Eugenia uniflora L.. A experiment was developed in the greenhouse of the Laboratory of Vegetal Phisiology, UFRPE, Brazil, between December 2010 and April 2011. The experimental was designed with four treatments: 0 (control), 30, 60 and 90 mM NaCl with five repetitions each treatment. At 35 and 95 days of experiment physiological analysis were performed. It was measured the leaf hydric potential and the relative water content, at two different moments: pre-morning, AND MID DAY and the photosynthetic pigments. The high evaporative demand (mid day) caused significant reductions in the leaf hydric potential and relative water content in the E. uniflora. At the referred times it was also possible to observe differences in the photosynthetic pigments between the levels of stressing. Results indicate that the imposition of high salinity reduced the hydric status of the subjects. Relating to the photosynthetic pigments the short-term salt stress caused a reduction that was overcome in the long-term stressing. The most affected pigment studied were the carotenoids. Keywords: Leaf hydric potential, relative water content, salt stress, photosynthetic pigments
40
van der Kooi, Casper J., J. Theo M. Elzenga, Marten Staal e Doekele G. Stavenga. "How to colour a flower: on the optical principles of flower coloration". Proceedings of the Royal Society B: Biological Sciences 283, n. 1830 (11 maggio 2016): 20160429. http://dx.doi.org/10.1098/rspb.2016.0429.
Testo completoAbstract (sommario):
The coloration of flowers is due to the wavelength-selective absorption by pigments of light backscattered by structures inside the petals. We investigated the optical properties of flowers using (micro)spectrophotometry and anatomical methods. To assess the contribution of different structures to the overall visual signal of flowers, we used an optical model, where a petal is considered as a stack of differently pigmented and structured layers and we interpreted the visual signals of the model petals with insect vision models. We show that the reflectance depends, in addition to the pigmentation, on the petal's thickness and the inhomogeneity of its interior. We find large between-species differences in floral pigments, pigment concentration and localization, as well as floral interior structure. The fractions of reflected and transmitted light are remarkably similar between the studied species, suggesting common selective pressures of pollinator visual systems. Our optical model highlights that pigment localization crucially determines the efficiency of pigmentary filtering and thereby the chromatic contrast and saturation of the visual signal. The strongest visual signal occurs with deposition of pigments only on the side of viewing. Our systematic approach and optical modelling open new perspectives on the virtues of flower colour.
41
Uysal, Mucteba. "The Use of Waste Maroon Marble Powder and Iron Oxide Pigment in the Production of Coloured Self-Compacting Concrete". Advances in Civil Engineering 2018 (2018): 1–10. http://dx.doi.org/10.1155/2018/8093576.
Testo completoAbstract (sommario):
This work covers some workability, mechanical, and durability properties of coloured self-compacting concrete (SCC) containing maroon marble powder and iron oxide pigment. Pigments with varying amounts were used to produce coloured SCC. For this purpose, ten different series were prepared of which two of the series were pigment free that one of them was the colour of white SCC including limestone powder and the other one was the colour of maroon SCC including maroon marble powder. The other series were containing pigments with varying amounts. The water to binder ratio remained constant for all the series at 0.42. Slump flow, T50 time, V-funnel, and L-box tests were used to determine the workability of coloured SCC. The hardened properties that were determined included density, water absorption, ultrasonic pulse velocity (UPV), compressive strength, abrasion resistance, and impermeability. As workability, experimental results showed that coloured SCC could be obtained by using maroon marble powder and when iron oxide pigment used in amounts less than 6%. The addition of pigment notably increased the water absorption of SCC series. The use of smaller quantities of pigment caused slight increase in compressive strength. Higher pigment content also provided decreases in abrasive resistance, and after exposure to abrasion, mass losses were within the range of 0.89%–2.12% and the abrasion depths were within the range of 0.9 mm–2.1 mm. Among the varying amounts of pigmented series, M1 series which contains 1% pigment showed the best performance, and the findings indicated that it is possible to successfully utilize maroon marble powder and lower amounts of pigments in producing coloured SCC.
42
Agarwal, Himani, Sneh Bajpai, Arti Mishra, Isha Kohli, Ajit Varma, Mireille Fouillaud, Laurent Dufossé e Naveen Chandra Joshi. "Bacterial Pigments and Their Multifaceted Roles in Contemporary Biotechnology and Pharmacological Applications". Microorganisms 11, n. 3 (28 febbraio 2023): 614. http://dx.doi.org/10.3390/microorganisms11030614.
Testo completoAbstract (sommario):
Synthetic dyes and colourants have been the mainstay of the pigment industry for decades. Researchers are eager to find a more environment friendly and non-toxic substitute because these synthetic dyes have a negative impact on the environment and people’s health. Microbial pigments might be an alternative to synthetic pigments. Microbial pigments are categorized as secondary metabolites and are mainly produced due to impaired metabolism under stressful conditions. These pigments have vibrant shades and possess nutritional and therapeutic properties compared to synthetic pigment. Microbial pigments are now widely used within the pharmaceuticals, food, paints, and textile industries. The pharmaceutical industries currently use bacterial pigments as a medicine alternative for cancer and many other bacterial infections. Their growing popularity is a result of their low cost, biodegradable, non-carcinogenic, and environmentally beneficial attributes. This audit article has made an effort to take an in-depth look into the existing uses of bacterial pigments in the food and pharmaceutical industries and project their potential future applications.
43
N S, Delna, Renu Mishra e Anil Praksh. "A Brief Review on the Emerging Role of Bacterial Pigments: From Industrial Uses to Novel Therapeutic Applications". Asian Journal of Biotechnology and Bioresource Technology 10, n. 4 (5 settembre 2024): 12–17. http://dx.doi.org/10.9734/ajb2t/2024/v10i4214.
Testo completoAbstract (sommario):
Pigments produced by microorganisms are in high demand due to their safe, non-toxic, and biodegradable characteristics in both industrial and pharmaceutical fields. Using bacteria for pigment production offers several advantages, such as a short life cycle and ease of genetic modification. Numerous studies have highlighted that soil bacteria significantly contribute to the production of coloured pigments as secondary metabolites. Bacterial pigments are well-known for their antimicrobial, antioxidant, and anticancer properties, offering new therapeutic opportunities for the development of novel drugs. However, compared to fungal pigments, most bacterial pigments are still in the research and development stage. Hence, efforts to intensify bacterial pigment production are essential to make them readily available on the market at a low cost for various applications. This review article sheds light on bacterial pigments and their various applications based on the data available in the literature.
44
Hájková, T., e A. Kalendová. "The anticorrosion properties of pigments based on molybdates and tungstates surface-modified with conducting polymers". Koroze a ochrana materialu 61, n. 1 (1 marzo 2017): 7–18. http://dx.doi.org/10.1515/kom-2017-0001.
Testo completoAbstract (sommario):
Abstract The objective of this work was to examine the properties of molybdate or tungstate based pigments whose surface has been coated with a conductive polymer, viz. either polyaniline phosphate (PANI) or polypyrrole phosphate (PPY), if used as pigments in organic coating materials. The anticorrosion pigments were prepared by high-temperature solid-state synthesis from the respective oxides, carbonates. The composite pigments (pigment/conductive polymer) were dispersed in a solvent-type epoxy-ester resin binder to obtain a series of paints whose anticorrosion properties were assessed by means of corrosion tests in accelerated corrosion test and by the linear polarisation method. Focus was on the anticorrosion properties of the paints depending on the pigment surface treatment, initial pigment composition, and pigment volume concentration (PVC) in the paint. The surface-treated pigment particles were expected to have a favourable effect on the anticorrosion and the mechanical properties of epoxy-ester resin based paints.
45
Mackinson, B. L., S. B. Moran, M. W. Lomas, G. M. Stewart e R. P. Kelly. "Estimates of micro-, nano-, and picoplankton contributions to particle export in the northeast Pacific". Biogeosciences 12, n. 11 (5 giugno 2015): 3429–46. http://dx.doi.org/10.5194/bg-12-3429-2015.
Testo completoAbstract (sommario):
Abstract. The contributions of micro-, nano-, and picoplankton to particle export were estimated from measurements of size-fractionated particulate 234Th, organic carbon, and phytoplankton indicator pigments obtained during five cruises between 2010 and 2012 along Line P in the subarctic northeast Pacific Ocean. Sinking fluxes of particulate organic carbon (POC) and indicator pigments were calculated from 234Th–238U disequilibria and, during two cruises, measured by a sediment trap at Ocean Station Papa. POC fluxes at 100 m ranged from 0.65 to 7.95 mmol m−2 d−1, similar in magnitude to previous results at Line P. Microplankton pigments dominate indicator pigment fluxes (averaging 69 ± 19% of total pigment flux), while nanoplankton pigments comprised the majority of pigment standing stocks (averaging 64 ± 23% of total pigment standing stocks). Indicator pigment loss rates (the ratio of pigment export flux to pigment standing stocks) point to preferential export of larger microplankton relative to smaller nano- and picoplankton. However, indicator pigments do not quantitatively trace particle export resulting from zooplankton grazing, which may be an important pathway for the export of small phytoplankton. These results have important implications for understanding the magnitude and mechanisms controlling the biological pump at Line P in particular, and more generally in oligotrophic gyres and high-nutrient, low-chlorophyll (HNLC) regions where small phytoplankton represent a major component of the autotrophic community.
46
Mackinson, B. L., S. B. Moran, M. W. Lomas, G. M. Stewart e R. P. Kelly. "Estimates of micro-, nano-, and picoplankton contributions to particle export in the northeast Pacific". Biogeosciences Discussions 11, n. 8 (27 agosto 2014): 12631–71. http://dx.doi.org/10.5194/bgd-11-12631-2014.
Testo completoAbstract (sommario):
Abstract. The contributions of micro-, nano-, and picoplankton to particle export were estimated from measurements of size-fractionated particulate 234Th, organic carbon, and phytoplankton indicator pigments obtained during five cruises between 2010 and 2012 along Line P in the subarctic northeast Pacific Ocean. Sinking fluxes of particulate organic carbon (POC) and indicator pigments were calculated from 234Th–238U disequilibria and, during two cruises, measured by sediment trap at Ocean Station Papa. POC fluxes at 100 m ranged from 0.65–7.95 mmol m−2 d−1, similar in magnitude to previous results at Line P. Microplankton pigments dominate indicator pigment fluxes (averaging 69 ± 19% of total pigment flux), while nanoplankton pigments comprised the majority of pigment standing stocks (averaging 64 ± 23% of total pigment standing stock). Indicator pigment loss rates (the ratio of pigment export flux to pigment standing stock) point to preferential export of larger microplankton relative to smaller nano- and picoplankton. However, indicator pigments do not quantitatively trace particle export resulting from zooplankton grazing, which may be an important pathway for the export of small phytoplankton. These results have important implications for understanding the magnitude and mechanisms controlling the biological pump at Line P in particular, and more generally in oligotrophic gyres and high-nutrient, low-chlorophyll regions where small phytoplankton represent a major component of the autotrophic community.
47
Puspita, Dhanang, Isnaini K. Putri, Fitri H. Al-Janati e Milka M. Mulyanto. "Isolasi, Identifikasi Pigmen, dan Analisis Aktivitas Antioksidan Pigmen Monascus". JURNAL BIOLOGI PAPUA 12, n. 2 (30 settembre 2020): 102–8. http://dx.doi.org/10.31957/jbp.1148.
Testo completoAbstract (sommario):
Monascus is a type of organism that can produce natural pigments. Monascus pigments have been widely used in the food and pharmaceutical industries. Besides having natural pigments, Monascus also contains antioxidants as preventing of the free radicals. The purpose of this study is to isolate, identify the type of pigment, and analyze antioxidant activity. This research method is divided into 3 stages; Monascus isolation, pigment identification with UV-vis spectrophotometer and TLC, and calculation of antioxidant activity with DPPH. The isolated Monascus had 3 pigment fractions and contained a total carotenoid of 18.55 µg/g, total orange pigment of 278.25 units/mL, and red pigment of 235.75 units/mL. Antioxidant activity of 4.22 ppm and included in the high category. Key words: antioxidant; monascus; pigment.
48
Song, Jie, Min Zhang, Yuan Tian e Sha Sha An. "Study on the Preparation and Performance of Natural Polygonum Cuspidatum Sieb.et Zucc Pigments Dyed PBS Composite". Advanced Materials Research 393-395 (novembre 2011): 1497–500. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.1497.
Testo completoAbstract (sommario):
The Polygonum Cuspidatum Sieb.et Zucc natural pigments were extracted and compounded with PBS in this paper. The performances of the pigment and the dyed films were studied. The results showed that: both the natural pigment and the dyed films had good thermal stability. Under the acidic conditions, the absorbance of the pigment changed little. The effect to the dyed films by pH indicated the pigments dissolved out of PBS with the degradation. The antibacterial evaluation demonstrated that the natural pigments had good inhibition against Staphylococcus aureus and Escherichia coli. The antibacterial properties of the films were not obvious, but it also revealed that the pigment and PBS had the good compatibility.
49
Ren, Jie, Cunjin Gao, Jigang Wang, Yang Shen, Jilong Shi, Quanxiao Liu e Wei Chen. "Non-invasive Optical Technical Identification of Red Pigments on Chinese Paper Notes". Coatings 11, n. 4 (1 aprile 2021): 410. http://dx.doi.org/10.3390/coatings11040410.
Testo completoAbstract (sommario):
Red pigments with bright colors were widely used in ancient Chinese painted pottery, books, antiques, calligraphy, and paintings. Herein, red pigments of traditional paper notes were investigated by non-invasive optical technology in order to enrich the Chinese historical pigments knowledge base. The results of laser Raman spectroscopy tests on five paper notes clearly identified the inorganic mineral pigments including ocher and cinnabar. Infrared spectroscopy measurements indicated that an artificial synthetic magenta was employed as the organic pigment. Inorganic and organic red pigments were applied together on the same samples 2 and 5 which can be speculated to serve an anti-counterfeiting function. In addition, SEM-EDS analysis of sample 5 clearly showed that the red pigment was composed of lead oxides and ZnS was added as color modulator. Combined with the abovementioned non-invasive techniques, analysis of printed pigments can provide a feasible method to authenticate and conserve paper notes.
50
Carvalho, Livia S., Wayne L. Davies, Phyllis R. Robinson e David M. Hunt. "Spectral tuning and evolution of primate short-wavelength-sensitive visual pigments". Proceedings of the Royal Society B: Biological Sciences 279, n. 1727 (22 giugno 2011): 387–93. http://dx.doi.org/10.1098/rspb.2011.0782.
Testo completoAbstract (sommario):
The peak sensitivities ( λ max ) of the short-wavelength-sensitive-1 (SWS1) pigments in mammals range from the ultraviolet (UV) (360–400 nm) to the violet (400–450 nm) regions of the spectrum. In most cases, a UV or violet peak is determined by the residue present at site 86, with Phe conferring UV sensitivity (UVS) and either Ser, Tyr or Val causing a shift to violet wavelengths. In primates, however, the tuning mechanism of violet-sensitive (VS) pigments would appear to differ. In this study, we examine the tuning mechanisms of prosimian SWS1 pigments. One species, the aye-aye, possesses a pigment with Phe86 but in vitro spectral analysis reveals a VS rather than a UVS pigment. Other residues (Cys, Ser and Val) at site 86 in prosimians also gave VS pigments. Substitution at site 86 is not, therefore, the primary mechanism for the tuning of VS pigments in primates, and phylogenetic analysis indicates that substitutions at site 86 have occurred at least five times in primate evolution. The sole potential tuning site that is conserved in all primate VS pigments is Pro93, which when substituted by Thr (as found in mammalian UVS pigments) in the aye-aye pigment shifted the peak absorbance into the UV region with a λ max value at 371 nm. We, therefore, conclude that the tuning of VS pigments in primates depends on Pro93, not Tyr86 as in other mammals. However, it remains uncertain whether the initial event that gave rise to the VS pigment in the ancestral primate was achieved by a Thr93Pro or a Phe86Tyr substitution.