Search Results (8)

Coating systems used for anticorrosion protection usually consist of a primer, intermediate layers, and topcoats. Zinc-rich primers, which serve as cathodic and barrier protection, are widely used for the corrosion protection of steel structures. Due to the fact that the functioning of the above-mentioned coatings is related to the conduction of galvanic current, these types of coatings are highly pigmented with zinc (up to 80 wt% in the dry coating). This may result not only in a deterioration of the performance of the coating system but also have a negative impact on the environment. Taking the above into account, solvent-based and water-based organic epoxy primers with zinc content reduced to approximately 50% have been developed. Zinc pigments of different shapes and with different surface treatments were used in the primers, as well as pigments without chemical treatment but with the addition of nanoparticles. It was found that, depending on the type of zinc pigment, both the developed solvent-based and water-based primers demonstrate good protective properties comparable to traditional zinc-rich coatings. Water-based paints tend to absorb more moisture compared to solvent-based systems, but their water uptake reversibility is limited. Moreover, the organic treatment of zinc flakes helps to improve this water uptake reversibility, improving the mechanical properties of coatings. Full article

In the last few years, the role of science in Cultural Heritage has assumed greater significance since diagnostics have become essential for the characterization of artworks. The development of conservation strategies involves growing the study of artworks and the knowledge of the materials used against the degradation plaguing the painted surfaces. This work focuses on the investigation of the degradation processes involving paintings on canvas, in particular delamination and progressive deterioration of the painted surfaces. The main causes of the degradation are attributable to the formation of metal soaps, which originate from the interaction between binders and pigments; as a result, the process leads to the progressive fracturing of the paint film. Using various characterization techniques allowed us to acquire information on the structural and morphological properties of the binder resins and study the binder/pigment interaction during the degradation process to understand the quantity and quality of the acid sites present in the binders and, consequently, the potential reactivity with the cationic part of the pigments. The binders were also analyzed within paint layers in contact with zinc oxide to study the interactions and the possible formation of new species as metal soaps and metal oxalates that can modify the boundary among the painting layers and, consequently, the appearance of the artwork and its artistic value. Modifications after UV and thermal aging processes were observed using Infrared spectroscopy and thermogravimetric analysis. Zinc soap formation was observed after 7 h of a UV aging process and was correlated to the acidity of the resins. Full article

In light of expected climate change, it is important to seek nature-based solutions that can contribute to the protection of our planet as well as to help overcome the emerging adverse changes. In an agricultural context, increasing plant resistance to abiotic stress seems to be crucial. Therefore, the scope of the presented research was focused on the application of botanical extracts that exerted positive effects on model plants growing under controlled laboratory conditions, as well as plants subjected to sorbitol-induced osmotic stress. Foliar spraying increased the length and fresh mass of the shoots (e.g., extracts from Taraxacum officinale, Trifolium pratense, and Pisum sativum) and the roots (e.g., Solidago gigantea, Hypericum perforatum, and Pisum sativum) of cabbage seedlings grown under stressful conditions, as well as their content of photosynthetic pigments (Pisum sativum, Lens culinaris, and Hypericum perforatum) along with total phenolic compounds (Hypericum perforatum, Taraxacum officinale, and Urtica dioica). The antioxidant activity of the shoots measured with the use of DDPH (Pisum sativum, Taraxacum officinale, Urtica dioica, and Hypericum perforatum), ABTS (Trifolium pratense, Symphytum officinale, Valeriana officinalis, Pisum sativum, and Lens culinaris), and FRAP (Symphytum officinale, Valeriana officinalis, Urtica dioica, Hypericum perforatum, and Taraxacum officinale) assays was also enhanced in plants exposed to osmotic stress. Based on these findings, the most promising formulation based on Symphytum officinale was selected and subjected to transcriptomic analysis. The modification of the expression of the following genes was noted: Bol029651 (glutathione S-transferase), Bol027348 (chlorophyll A-B binding protein), Bol015841 (S-adenosylmethionine-dependent methyltransferases), Bol009860 (chlorophyll A-B binding protein), Bol022819 (GDSL lipase/esterase), Bol036512 (heat shock protein 70 family), Bol005916 (DnaJ Chaperone), Bol028754 (pre-mRNA splicing Prp18-interacting factor), Bol009568 (heat shock protein Hsp90 family), Bol039362 (gibberellin regulated protein), Bol007693 (B-box-type zinc finger), Bol034610 (RmlC-like cupin domain superfamily), Bol019811 (myb_SHAQKYF: myb-like DNA-binding domain, SHAQKYF class), Bol028965 (DA1-like Protein). Gene Ontology functional analysis indicated that the application of the extract led to a decrease in the expression of many genes related to the response to stress and photosynthetic systems, which may confirm a reduction in the level of oxidative stress in plants treated with biostimulants. The conducted studies showed that the use of innovative plant-based products exerted positive effects on crops and can be used to supplement current cultivation practices. Full article

The aim of the work was to investigate the prospects of imparting valuable physical and chemical properties, such as corrosion resistance, impact and bending strength, adhesion and storage stability, to hybrid systems of potassium and sodium silicates by modification with organic compounds. Here, we present the results of worldwide activities of scientific teams studying the manufacturing technology of modified liquid glass anticorrosive coatings used in chemical, petrochemical industry and modern construction. The authors theoretically and economically justified and put into practice novel organic and inorganic compositions with increased viability. The durable and waterproof coatings with good adhesion to various substrates (non-ferrous metals, steel, plastered surface and wood) were obtained. The authors demonstrate the possibility of recycling of zinc-containing rongalite production wastes and sludge pastes of electrochemical productions containing alkali and alkaline-earth metal cations by including them into the composition instead of pigmenting solid-phase components. We propose a technological route for obtaining anticorrosion coatings to protect aluminum and its alloys operated in a zone of elevated (up to 673 K) temperatures. Full article

Iron (Fe) deficiency exists as a widespread nutritional disorder in alkaline and calcareous soils; therefore, Fe-enriching strategies may be used to overcome this issue. Field experiments were conducted with a randomized complete design with three replicates for evaluating the effectiveness of iron oxide nanoparticles (Fe-NPs) against traditional Fe compounds (sulfate or chelate), which have various shortcomings on Rose-scented geranium (RSG) herb in terms of plant growth, phytopharmaceuticales, essential oil (EO), and its constituents. Supplementation of Fe-sources considerably improved RSG plant growth and EO yield in the 1st and 2nd cut throughout the two seasons over non-treated control plants. A total of 11 compounds of RSG-EO were identified; the main constituents were citronellol, geraniol, and eugenol. The results indicate that EO composition was significantly affected by Fe-sources. Amendments of Fe-sources considerably augmented photosynthetic pigments, total carbohydrates, nitrogen, phosphorous, potassium, iron, manganese, zinc, phenols, flavonoids, and anthocyanin. Commonly, Fe-NPs with humic acid (Fe-NPs-HA) supplementation was superior to that of traditional sources. The highest values were recorded with spraying Fe-NPs-HA at 10 mg L⁻¹ followed by 5 mg L⁻¹, meanwhile, the lowest values were recorded in untreated control plants. Current findings support the effectiveness of nanoparticle treatment over Fe-sources for improving growth and yield while also being environmentally preferred in alkaline soil. These modifications possibly will be applicable to EO quality and its utilization in definite food and in medical applications. Full article

This paper presents the results of an extensive study of 14 paintings by the pioneering Singapore artist Liu Kang (1911–2004). The paintings are from the National Gallery Singapore and Liu family collections. The aim of the study is to elucidate the painting technique and materials from the artist’s early oeuvre, Paris, spanning the period from 1929 to 1932. The artworks were studied with a wide array of non- and micro-invasive analytical techniques, supplemented with the historical information derived from the Liu family archives and contemporary colourmen catalogues. The results showed that the artist was able to create compositions with a limited colour palette and had a preferential use of commercially available ultramarine, viridian, chrome yellow, iron oxides, organic reds, lead white, and bone black bound in oil that was highlighted. This study identified other minor pigments that appeared as hue modifications or were used sporadically, such as cobalt blue, Prussian blue, emerald green, cadmium yellow, cobalt yellow, and zinc white. With regard to the painting technique, the artist explored different styles and demonstrated a continuous development of his brushwork and was undoubtedly influenced by Modernists’ artworks. This comprehensive technical study of Liu Kang’s paintings from the Paris phase may assist art historians and conservators in the evaluation of the artist’s early career and aid conservation diagnostics and treatment of his artworks. Furthermore, the identified painting materials can be compared with those used by other artists active in Paris during the same period. Full article

Microalgae are promising photosynthetic unicellular eukaryotes among the most abundant on the planet and are considered as alternative sustainable resources for various industrial applications. Chlamydomonas is an emerging model for microalgae to be manipulated by multiple biotechnological tools in order to produce high-value bioproducts such as biofuels, bioactive peptides, pigments, nutraceuticals, and medicines. Specifically, Chlamydomonas reinhardtii has become a subject of different genetic-editing techniques adapted to modulate the production of microalgal metabolites. The main nuclear genome-editing tools available today include zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs), and more recently discovered the clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein (Cas) nuclease system. The latter, shown to have an interesting editing capacity, has become an essential tool for genome editing. In this review, we highlight the available literature on the methods and the applications of CRISPR-Cas for C. reinhardtii genetic engineering, including recent transformation methods, most used bioinformatic tools, best strategies for the expression of Cas protein and sgRNA, the CRISPR-Cas mediated gene knock-in/knock-out strategies, and finally the literature related to CRISPR expression and modification approaches. Full article

It is known that oil paintings containing zinc white are subject to rapid degradation. This is caused by the interaction between the active groups of binder and the metal ions of the pigment, which gives rise to the formation of new zinc complexes (metal soaps). Ongoing studies on zinc white paints have been limited to the chemical mechanisms that lead to the formation of zinc complexes. On the contrary, little is known of the photo-physical changes induced in the zinc oxide crystal structure following this interaction. Time-resolved photoluminescence spectroscopy has been applied to follow modifications in the luminescent zinc white pigment when mixed with binder. Significant changes in trap state photoluminescence emissions have been detected: the enhancement of a blue emission combined with a change of the decay kinetic of the well-known green emission. Complementary data from molecular analysis of paints using Fourier transform infrared spectroscopy confirms the formation of zinc carboxylates and corroborates the mechanism for zinc complexes formation. We support the hypothesis that zinc ions migrate into binder creating novel vacancies, affecting the photoluminescence intensity and lifetime properties of zinc oxide. Here, we further demonstrate the advantages of a time-resolved photoluminescence approach for studying defects in semiconductor pigments. Full article