White Research Articles

Establishment of pupal color as a screening marker and activity analysis of six U6 promoters in Zeugodacus cucurbitae using the white pupae gene.

The genetic control method, which is environmentally friendly and species-specific, has effectively reduced or eliminated pests in many areas. One essential requirement to control a species is the identification of its genetic and molecular elements. Such elements, however, are rarely available in Zeugodacus cucurbitae, a very destructive insect pest worldwide. In this study, we knocked out the white pupae (wp) gene in Z. cucurbitae and generated a wp(-) strain, which has a white pupae phenotype. The white puparium color was successfully restored to brown by inserting the wp gene rescue allele into the genome of the wp(-) strain using piggyBac transgenic technology. The potential wp promoter was then truncated to drive the expression of the wp gene and the puparium color was rescued even by the 605 bp sequence upstream of its transcription initiation site. Further fertility tests showed that knocking out or rescuing the wp gene had no effect on the reproduction of adult flies. In addition, we identified six U6 promoters and tested their promoter activities in the embryos of Z. cucurbitae. The ZcU6-2 and ZcU6-1 promoters exhibited significantly higher activity than the others and are suitable for use in CRISPR technology-based genetic control methods. Our work first shows the success of applying piggyBac transgenic technology in Z. cucurbitae. Our results demonstrate a highly efficient transgenic screening marker by puparium color and the promoter activity of multiple ZcU6 promoters, facilitating the construction of transgenic strains that are used for genetic control of tephritid species. © 2025 Society of Chemical Industry.

Soil data from the Barbastro-Balaguer gypsum belt, NE Spain.

The dataset [1] hosts pedological info and images of the lands -locally known as chesas- of the outcropping gypsiferous core of the Barbastro-Balaguer anticline (Fig. 1). It stands out in the landscape for the linear reliefs due to outcrops of dipping strata with differential resistance to erosion, and also because of its whitish color (Fig. 2) and gypsophilous vegetation. This gypsum outcrop was named in the 19th Century [2] as a gypseous belt, and has been further studied by other geologists like [3,4] and by civil engineers e.g. Hué and Llamas [5]. Traditionally chesas were rangeland, with sparse almond and olive trees and rainfed winter cereals confined at the flat -and often terraced- valley bottoms, or vales as known in NE Spain. The chesas have attracted the attention of botanists [[6], [7], [8]], foresters [9,10], and soil hydrophysical properties researchers [11]. Moreover, public interest is increasing as the administrations are establishing rules for nature protection in the gypseous lands, e.g., a demarcation of 137 km2 set within the chesas was declared a Special Conservation Area "ES2410074 Yesos de Barbastro", and then protected by the Habitats Directive of European Union. Also, plant physiologists are focusing on the adaptations of plants to gypsum as reviewed by Escudero et al. [12]. No soil map is available, but according to [13,14] the Gypsic Haploxerepts [15] are dominant. In the absence of a soil map, our dataset can help in the decisions to be made by the authorities, as is the case for water allocation to irrigated estates both in operation and planned, or for authorizations for the spreading of pig slurry. The herein presented soil data were collected with the classical techniques of pedological prospection. The dataset [1] contains the scans in .TIFF format of 150 whole thin sections of the soils, under both plane polarized light (PPL) and cross polarized light (XPL). Moreover, this dataset directs to a freely downloadable book [16] with the corresponding pedological descriptions, chemical and physical analyses, hydrophysical data, and scanning electron microscope images of the soils, plus micrographs of relevant pedofeatures of thin sections seen under petrographic microscope. The dataset [1] also presents a .xlsx file with an English translation of all figure captions of [16], including those of micrographs, and two more .xlsx files with analytical data. All data can be reused directly by naturalists, engineers, technicians and public servants in charge of environmental law development and enforcement, as well as by people involved in citizen science activities. Thin sections remain stored at EEAD and can be examined at our premises upon request.

Microplastics in the surface waters of the northern South China Sea: Interannual variation and potential ecological risks.

Microplastic pollution in marine environments has become a global concern due to its potential ecological risks. However, long-term data on microplastic distribution are scare, hindering the assessment of the ecological threats. This study monitored microplastics pollution in the surface water of the northern South China Sea from 2019 to 2023. The average abundance of microplastics exhibited an increasing trend from 2019 to 2021 and a subsequent decrease from 2021 to 2023 in both the Pearl River Estuary and Zhanjiang offshore waters. Conversely, a steady annual decrease was observed in the surface waters of Beibu Gulf from 2020 to 2023. The spatial variability of microplastic hotspot across different years and regions. Microplastics predominantly ranged from 1 to 2mm in size, with fragments and fibers being the most common shapes and transparent and white colors being the most prevalent. The primary chemical components of microplastics were polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). No significant inter-annual differences were observed in the physicochemical characteristics of microplastics. The pollution load index (PLI) indicated medium to low levels of microplastic pollution, with the potential ecological risk index (PERI) suggesting a low level of ecological risk, implying a minimal threat to the marine ecosystem. This study first revealed the annual variations in microplastic pollution and their potential ecological risks in the northern South China Sea, providing crucial data support for the future management and control of marine microplastic pollution.

SYNCAS based CRISPR-Cas9 editing in predatory mites, whiteflies and stinkbugs

Despite the establishment of CRISPR-Cas9 gene editing protocols in a wide range of organisms, genetic engineering is still challenging for many organisms due to constraints including lethality of embryo injection, difficulties in egg/embryo collection or viviparous lifestyles. Recently, an efficient CRISPR-Cas9 method, termed SYNCAS, was developed to genetically modify spider mites and thrips species. The method is based on maternal injection of formulated CRISPR-Cas9 using saponin and BAPC. Here, we investigate whether the method can be used to perform gene editing in other arthropods such as the beneficial predatory mites Amblyseius swirskii and Phytoseiulus persimilis, and the pests Bemisia tabaci and Nezara viridula. For the predatory mites, Antp and SLC25A38 were used as target genes, while the ortholog of the Drosophila melanogaster ABCG transporter white was targeted in B. tabaci and N. viridula. All species were successfully edited with the highest efficiencies (up to 39%) being obtained for B. tabaci. For A. swirskii and P. persimilis no clear phenotypes could be observed, even though SLC25A38 was successfully knocked-out. The lack of a color phenotype in SLC25A38 mutants was confirmed in the spider mite Tetranychus urticae. Disruption of the target gene Antp is likely lethal in predatory mites, as no true null mutants could be recovered. For B. tabaci, KO of white resulted in orange eyes which diverges from the phenotype seen in white mutants of D. melanogaster. In the last species, N. viridula, a single phenotypic mutant could be detected having a patchy white body coloration with wild type eye coloration. Genotyping revealed a single amino acid deletion at the target site, suggesting the creation of a hypomorphic allele. To conclude, the protocols provided in this work can contribute to the genetic study of predatory mites used in biological control, as well as hemipteran pests.

Tuning mechanoluminescence colors from aromatic imides with dyes

AbstractAromatic imides are an important class of organic mechanoluminescence (ML) compounds. Color is one of the most important ML properties, and it was previously modified by preparing various aromatic imide derivatives using chemical synthesis. In this report, we present a simple alternative strategy where a single aromatic imide is solution‐mixed and crystallized with commercial organic dyes to produce mixtures that exhibit new ML colors. Specifically, using an aromatic imide with blue ML in its pure form, the ML could be changed to pink, yellow, or a weak white color using Eosin Y, Fluorescein, or Acridine Orange, respectively. The resulting mixtures could also be incorporated into waste polystyrene plastic to make composite materials with ML behavior.

ИЗУЧЕНИЕ НОВЫХ СОРТОВ СОИ НА ПРИГОДНОСТЬ ДЛЯ ИЗГОТОВЛЕНИЯ СОЕВОГО ТВОРОГА – ТОФУ

The purpose of research is to study new soybean varieties (Puma, Barguzin, Sayana) for suitability for the manufacture of soybean curd – tofu with improved organoleptic characteristics. The physical indicators of raw materials were determined, the analysis of the biochemical composition of raw materials and finished products made from soybean varieties of a very early ripeness group of selection of the Federal State Budgetary Scientific Institution Federal Scientific Center, V.S. Pustovoit All-Russian Research Institute of Oil Crops, grown in the conditions of the Lipetsk Region. Tofu samples were made using an acid coagulant, the yield of products per unit of raw material was determined, and an organoleptic assessment of the quality of the finished product was carried out in comparison with a mass-produced sample presented in retail trade. The studied soybean varieties contained in their composition protein from 38.3 % in the Barguzin variety to 39.3 % in the Sayana variety in their composition, which during processing made it possible to obtain a finished product with a protein content from 16.0 % in the Sayana variety to 18.1 % in varieties Barguzin. The Puma variety with a thousand seed weight of 138.8 g made it possible to obtain the highest yield of the finished product (1034 g) from one kg of raw material, which is 54–94 g more compared to other studied varieties. The use of an acid coagulant contributed to the formation of a soft, but shape-retaining consistency of the finished product. Samples of bean curd made from the studied varieties had a neutral taste, a slight soy smell and a white color with a slight beige tinge. Soybean varieties Puma, Barguzin, Sayana, when grown in the Lipetsk Region, provide raw materials suitable for making high quality tofu.

Color Inside and Outside the Lines: Evidence From Eye‐Tracking Studies on Conformity to and Differentiation From Category Color Codes

ABSTRACTCategory color codes are commonly used hues in packaging within a specific product category. These colors establish visual standards for new products and influence consumer perception and product categorization. Product managers face a challenging decision: Should they conform to or differentiate from these established color norms? For example, should flour packaging adopt the typical white category color code or stand out with a distinctive color like purple? Retailers face a similar dilemma: Where should they place products that conform to or differ from these color norms to capture consumer attention effectively? Despite the relevance of category color codes for both manufacturers and retailers, the literature on this topic remains limited. Building upon the Limited Capacity Model of Motivated Mediated Message Processing, this paper examines how conformity or differentiation of main and secondary packaging colors from category codes impacts consumer attention. Findings from lab and field eye‐tracking studies reveal a negative interaction between the conformity of main and secondary colors with category codes on both the duration and number of fixations. Hybrid color combinations—where either the main or secondary color conforms while the other differentiates—are most effective in attracting consumer attention, which, in turn, influences consumer choice. This research expands the understanding of the trade‐off between conformity and differentiation in packaging color, offering theoretical contributions to the role of visual stimuli in attracting attention and providing practical guidance for managers in selecting optimal color combinations for their products.

The Impact of Color Combination on Visual Search Efficiency and User Experience in Human-Machine Interface: A Case Study of Metro Electronic Guide Screen

Color is an important attribute of human-perceived human-machine interface (HMI), and it is unclear which color combinations produce the best performance and user experience in visual search tasks. Taking the metro electronic guide screen (MEGS) as an example, the eye-tracking (E-T) device is used to record the pupil diameter and search time, and the Likert scale is used to evaluate the satisfaction and usability, and the influence of the four factors of background hue, saturation, brightness and text color in HMI on user search efficiency and user experience is discussed in depth. The results show that the recognition efficiency is best when the background hue is medium brightness, medium saturation green with white text color. Meanwhile, the results of user satisfaction and ease of use are basically consistent with the objective experimental results, and there is a certain correlation between the subjective preference of color combination and visual performance.

Performing social unease

By drawing insights from artistic practice and utilizing conceptual and methodological approaches from the philosophy of embodied cognition, my purpose is to investigate the transformative possibilities embedded in creatively exploring social unease. To do so, I will present an art project, Biston betularia carbonaria, which involves the performative activation of a cast of a moth chrysalis through the waving of a flag and the ignition of a black smoke grenade. Biston betularia is a lepidopteran of the family Geometridae; the most widespread species is the typica, whose white color, in the course of its evolution, has enabled it to camouflage itself on birch trunks and thus escape predators. In nineteenth-century cities, air pollution caused by industrialization darkened the bark of trees, therefore promoting the survival of the melanic species called carbonaria, characterized by its black color. As pollution diminished, the typical form gradually regained its status as the dominant species.

The red colour in chinicuil (Comadia redtenbacheri (Hammerschmidt)) is due to rhodommatin pigment

Abstract In Mexico, Comadia redtenbacheri (Hammerschmidt) is called chinicuil or agave red worm which is highly appreciated since pre-Hispanic period and was considered a delicacy greatly accept by the Aztec. At present, chinicuil is highly valued not only for its culinary value but also as an ornamental in the mezcal industry, although it has not been possible to preserve its intense red colour. One reason for this is probably that the pigment responsible for the reddish coloration of the chinicuil has not yet been identified, making it difficult to find a possible alternative for its preservation. For this reason, the aim of this research was to elucidate the chemical structure of the pigment responsible for the reddish coloration of chinicuil in order to expand knowledge of its properties and offer alternatives for colour preservation.. According to the results of this study, the size is decisive for the colour of the larvae. The small larvae are white, while the large larvae are reddish in colour. The results of the colour characteristics of the larvae showed that the large larvae tend to have a reddish coloration, while a yellowness or white coloration is observed in the other larval sizes. The chromatographic UV-Vis profile of the pigment in the large larvae showed signals characteristic of the ommochromes, which was confirmed by the 1H NMR spectra, in which characteristic signals of the aromatic rings, glycosides, carboxyl and amine groups were detected. These results lead to the conclusion that the principal pigment that gives the chinicuil its red colour is rhodommatin.

Integrated metabolomic and transcriptomic analysis of anthocyanin metabolism in wheat pericarp

BackgroundWheat seeds display different colors due to the types and contents of anthocyanins, which is closely related to anthocyanin metabolism. In this study, a transcriptomic and metabolomic analysis between white and purple color wheat pericarp aimed to explore some key genes and metabolites involved in anthocyanin metabolism.ResultsTwo wheat cultivars, a white seed cultivar Shiluan02-1 and purple seed cultivar Hengzi151 were used to identify the variations in differentially expressed genes (DEGs) and differentially accumulated flavonoids (DAFs). Based on metabolomic data, 314 metabolites and 191 DAFs were identified. Chalcone, flavonol, pro-anthocyanidin and anthocyanidin were the most differentially accumulated flavonoid compounds in Hengzi151. 2610 up-regulated and 2668 down-regulated DEGs were identified according to transcriptomic data. The results showed that some structural genes in anthocyanin synthesis pathway were prominently activated in Hengzi151, such as PAL, CAD, CHS and so on. Transcription factors (TFs) of MYB, bHLH, WD40 and some other TFs probably involved in regulating anthocyanin biosynthesis were identified. Some genes from hormone synthetic and signaling pathways that may participate in regulating anthocyanin biosynthesis also have been identified.ConclusionsOur results provide valuable information on the candidate genes and metabolites involved in the anthocyanin metabolism in wheat pericarp.

Meat consumption and racial/ethnic disparities in population-based study in the city Campinas, Brazil

The aim of the present study was to investigate meat consumption among adults residing in a city in the countryside of São Paulo, Campinas, according to ethnicity/skin color in two periods: 2008/2009 and 2014/2015, given the scarce literature on the subject. Thus, we sought to evaluate the association between race/color and consumption of meat, a food of great cultural value, based on the hypothesis that this demographic marker is relevant to explain food choices. A cross-sectional population-based study evaluating participants from the Health Survey of the City of Campinas (ISACAMP) was conducted in 2008/2009 and 2014/2015, with 2,354 and 1,606 individuals respectively, aged 20y or older. Food consumption data were collected using the 24-hour food recall method and meats were classified according to animal origin and type of processing. Linear regression models were run to assess the association between meat consumption and sociodemographic variables with a significance level of 5%. Lower total consumption of meat, red meat, beef and fish was found among individuals with self-declared black skin color compared to those with self-declared white skin color. Red meat consumption varied from 109.4g to 157.9g in 2008/2009 and from 102.1g to 125.1g in 2014/2015 between the groups, remaining above the recommendation in both periods. The World Cancer Research Fund recommends consuming between 50 and 71.4 g/day of red meat; thus, these findings reinforce the importance of studies that investigate the impact of ethnicity on food consumption, since racial disparities may be in the origin of the insufficient or excessive consumption of certain types of meat, and understanding the factors associated with the consumption of types of meat is relevant for the adoption of health actions aimed at adequate food intake.

Effects of the Interactions Between Food Additive Titanium Dioxide and Matrices on Genotoxicity.

Titanium dioxide (TiO2), a white color food additive, is widely used in bakery products, candies, chewing gums, soups, and creamers. Concerns about its potential genotoxicity have recently emerged, particularly following the European Union's ban on its usage as a food additive due to its genotoxicity potential. Conflicting in vitro and in vivo results regarding its genotoxicity highlight the need for further in-depth investigation. Moreover, food additives can interact with food components or biological matrices, potentially altering their biological responses and genotoxicity. In this study, we evaluated the interactions between two different sizes of additive TiO2 particles and food or biological matrices, including albumin, fetal bovine serum (FBS), and glucose. The results showed that the hydrodynamic diameters of TiO2 increased upon interaction with albumin or FBS, but not with glucose. The presence of albumin or FBS reduced TiO2-induced cytotoxicity, oxidative stress, in vitro intestinal transport, and ex vivo intestinal absorption to untreated control levels, regardless of particle size. While TiO2 caused DNA damage in intestinal Caco-2 cells, the interactions with albumin or FBS significantly reduced the DNA damage to levels comparable to untreated controls. The DNA damage was closely related to oxidative stress caused by TiO2. These findings suggest that the interaction of TiO2 with albumin or FBS, resulting in increased hydrodynamic diameters, mitigates its cytotoxicity, oxidative stress, intestinal transport, and genotoxicity. Further investigation is required to fully understand the potential genotoxicity of TiO2 in food contexts.

A suite of pre-assembled, pET28b-based Golden Gate vectors for efficient protein engineering and expression.

Expression and purification of recombinant proteins in E. coli is a bedrock technique in biochemistry and molecular biology. Expression optimization requires testing different combinations of solubility tags, affinity purification techniques, and site-specific proteases. This optimization is laborious and time consuming as these features are spread across different vector series and require different cloning strategies with varying efficiencies. Modular cloning kits based on the Golden Gate system exist, but are overly complicated for many applications, such as undergraduate research or simple screening of protein purification features. An ideal solution is for a single gene synthesis or PCR product to be compatible with a large series of pre-assembled Golden Gate vectors containing a broad array of purification features at either the N or C-terminus. To our knowledge, no such system exists. To fulfill this unmet need, we Golden Gate domesticated the pET28b vector and developed a suite of 21 vectors with different combinations of purification tags, solubility domains, visualization/labeling tags, and protease sites. We also developed a completely scarless vector series with 9 different N-terminal tags. The system is modular, allowing users to easily customize the vectors with their preferred combinations of features. To allow for easy visual screening of cloned vectors, we optimized constitutive expression of the fluorescent protein mScarlet3 in the reverse strand, resulting in a red to white color change upon successful cloning. Testing with the model protein sfGFP shows the ease of visual screening, high efficiency of cloning, and robust protein expression. These vectors provide versatile, high-throughput solutions for protein engineering and functional studies in E. coli.

Extraction of Cellulose from Sugarcane Bagasse Across Agricultural and Forestry

This study investigates the sustainable cellulose extraction from sugarcane bagasse across agricultural, forestry, and plantation sectors. Sugarcane bagasse, a by-product of sugar production, emerges as a promising source of cellulose, offering avenues for value addition and waste reduction within these industries. Three extraction methods were evaluated: soxhlet extraction using ethanol, kraft pulping with NaOH/Na2S, and iCEL machine producing cellulose, extractive, and lignin. Quantitative analysis reveals that soxhlet extraction yields the highest purity of cellulose (75.86±1.54%), followed by the iCEL machine (50.20 ± 12.49%), while kraft pulping shows comparatively lower purity (48.42±3.95%) due to incomplete delignification. Morphological examination indicates that soxhlet extraction preserves cellulose’s native properties, including its white colour and fibrous morphology akin to raw cotton. In contrast, kraft pulping induces degradation, leading to yellowing and lignification of the cellulose. Fourier transform infrared spectroscopy confirms the presence of characteristic cellulose peaks in all samples, with additional peaks indicating residual non-cellulosic components, especially in kraft cellulose. Soxhlet extraction is optimal due to its simplicity, higher purity, and non-destructive nature. Despite its industrial prevalence, kraft pulping exhibits lower efficiency in cellulose extraction. While the iCEL method shows promise, further optimization is needed to enhance consistency. Future research directions may include adapting soxhlet parameters for nanocellulose production and characterizing material properties for diverse applications. Economic feasibility and environmental impact assessments are crucial for the commercialization of lab protocols, thereby supporting sustainable cellulose production from abundant agricultural residues like sugarcane bagasse. In conclusion, this study underscores the importance of exploring efficient and sustainable methods for cellulose extraction from sugarcane bagasse, with implications for promoting circular economy principles and fostering sustainable development across agricultural, forestry, and plantation sectors.

Polyphenolic Profiling and Wound Healing Potential of Hammada scoparia (Pomel) Iljin: Preclinical Evaluation of a Novel Topical Formula

Objective Hammada Scoparia (Pomel) as an endemic plant from the Amaranthaceae family, holds a significant position in the Saharan region of southern Algeria's traditional medicine. The aerial parts of Hammada scoparia was used to cure inflammation and wound healing management. The aim of this study was to determine the phytochemical constituents of the aqueous extract obtained from the aerial parts of Hammada scoparia (AEHs)and assess its effectiveness in wound healing. Methods Formulation of Wound healing cream were prepared from Hammada scoparia aerial parts aqueous extract then the wounds were applied on the skin of the dorsal region of each Wistar albino for 13 days. Hematological, inflammation and histological parameters were evaluated. Different bioactive compounds were identified within AEHs using HPLC analysis. Results High-Performance Liquid Chromatography (HPLC) analysis identified 21 phenolic compounds, with rutin being the most abundant, followed by naringenin, gallic Acid, valinin, and hydroxy-comarin. The formulated AEHs cream exhibited superior wound healing properties, with a 96.54% healing rate by day 13, outperforming the DOUCE PLUS cream and control groups. Physical analyses indicated the cream's white color, neutral odor, humid texture, pH of 6.8, and excellent stability. Hematological parameters revealed the AEHs cream influenced red blood cells (RBCs), white blood cells (WBCs), and platelet (PLT) levels positively. Inflammation markers, including C-reactive protein (CRP) and sedimentation rate (ESR), were also favorably modulated by the treatment. Histological studies indicated that H. scoparia cream promoted re-epithelialization, fibroblast activity, collagen deposition, and angiogenesis, thus facilitating an effective healing process. Conclusion The study concludes that Hammada scoparia possess significant wound healing properties, corroborating their traditional medicinal use.

Throat colour polymorphism in relation to sex and body size of the Litter skink Lankascincus fallax

Colour polymorphism is a pervasive phenomenon in both the animal and plant kingdoms and understanding its evolution and maintenance is of great interest. Among the lizards of Sri Lanka, the endemic skink Lankascincus fallax shows throat colour polymorphism in which the underlying basis is not clearly known. In this study, we examined the relationship of the three different throat colour morphs observed in this species with sex, body size and geographic location. Live skinks were sampled from two locations in Sri Lanka and sex and throat colour were categorised visually and the snout-vent length (SVL) was measured. Tail tips of some selected individuals from the two locations were taken and a fragment of the 12S rRNA gene was sequenced in representative individuals having different throat colour morphs. Pairwise genetic distance of the three colour morphs ranged between 0.4–0.5%, confirming that the three colour morphs were the same species. The three throat colour morphs (red, black and white) were observed in males in both locations, while the females only had the white morph. This suggests that throat colour in this species is linked to sex and that the throat colour polymorphism was confined to males. There was a significant difference between the mean SVL of males with red and black throat colours (39.36 mm) and males with white throat colours (31.93 mm), suggesting that the throat colour is associated with the body size in males. However, future studies are necessary to understand the underlying drivers for the presence and maintenance of sexual dichromatism and throat colour polymorphism in L. fallax.

Blended-red lighting partially mitigates the cost of light pollution for arthropods

Light pollution disrupts the natural dark–light rhythmicity of the world and alters the spectral composition of the nocturnal sky, with far-reaching impacts on natural systems. While the costs of light pollution are now documented across scales and taxa, community-level mitigations for arthropods remain unclear. To test two light pollution mitigation strategies, we replaced all 32 streetlights in the largest visitor center in Grand Teton National Park (Wyoming, USA) to allow wireless control over each luminaries’ color and brightness. We captured fewer arthropods, across most Orders, in the blended-red light compared to white (3000 K). Interestingly, we found an effect of light brightness and color, suggesting that, overall, more arthropods were attracted by brighter, and white color hues compared to blended-red. Our findings provide valuable insights into the mitigation of artificial light at night, likely one of the primary drivers of global arthropod declines.

Colour in Iberian Iron Age architectural sculpture: the case of Cerro de la Merced

Recently, analytical research has confirmed the use of pigments in Iberian Iron Age freestanding sculpture. However, hard evidence of polychromy on the many preserved remains of architectural sculpture is still scarce. We focus on the case of a large block decorated with reliefs, probably dated to the end of the 5th or the beginning of the 4th century BCE, recently found at Cerro de la Merced (Cabra, Córdoba). Employing optical and electron microscopy analyses, FTIR spectroscopy, and GC-MS, it has been possible to confirm the existence of traces of red and white colour covering the entire surface, analyse the composition of the pigments employed, and to reconstruct the colour patterns of the different elements of the relief. Our aim is to deepen our understanding of the use of colour in Iberian architecture and to shed light on the colours employed, the techniques used to apply them and their arrangement patterns.

Photochromism in the periodic nanospace of zeolite LTA by the transfer of photoexcited electrons of adsorbed Na atoms.

Cationic sodium (Na) clusters incorporated into a dehydrated Na-form LTA (Na-LTA) zeolite by the adsorption of Na atoms exhibit diamagnetism regardless of their adsorption amount. These clusters preferentially form in β-cages under the condition of dilute adsorption. In this study, photochromism was observed on the dilute Na-adsorbed Na-LTA, which showed a color change from yellow-green to dark blue-green at room temperature. This phenomenon resulted in dissociation of the diamagnetic Na clusters in β-cages upon light irradiation and thereby in the formation of two metastable Na43+ clusters with C3v symmetry in α-cages from the photoabsorption and electron spin resonance spectra. We also observed photochromism in a sample of insufficiently dehydrated Na-LTA with dilute Na adsorption-i.e., the initial white color changed to blue, then blue-green and finally dark moss-green upon irradiation with UV light. This phenomenon consists of two steps. First, products in the β-cages, formed by the reaction of residual water molecules with adsorbed Na atoms, release electrons upon irradiation. The electrons transfer to the α-cages, forming the metastable Na43+ clusters. Next, the diamagnetic Na clusters are formed in vacant β-cages by the thermal transfer of electrons from the Na43+ clusters in the α-cages. Na clusters including multiple electrons were also formed in the α-cages by long exposure to UV light irradiation, which had a similar effect to increasing the adsorption amount of Na atoms onto the dehydrated Na-LTA. After termination of irradiation, the sample required a week to change its color to light yellow.