Compounds

Considerable attention has been paid to (1E)-1,2-diaryldiazenes (azo dyes) possessing liquid–crystalline (LC) and optical properties because they can switch color through thermal phase transitions and photoisomerizations. Although multifunctional molecules with both LC and fluorescent properties based on a donor–π-acceptor (D-π-A)-type tolane skeleton have been developed, functional molecules possessing LC and dye properties have not yet been developed. Therefore, this study proposes to develop LC dyes consisting of (1E)-1,2-diaryldiazenes with a D–π-A-type tolane skeleton as the aryl moiety. The (1E)-1,2-diaryldiazene derivatives exhibited a smectic phase, regardless of the flexible-chain structure, whereas the melting temperature was significantly increased by introducing fluoroalkyl moieties into the flexible chain. Evaluation of the optical properties revealed that compounds with decyloxy chains exhibited an orange color, whereas compounds with semifluoroalkoxy chains absorbed at a slightly blue-shifted wavelength, which resulted in a pale orange color. The thermal phase transition caused a slight color change accompanied by a change in the absorption properties, photoisomerization-induced shrinkage, and partial disappearance of the LC domain. These results indicate that (1E)-1,2-diaryldiazenes with a D–π-A-type tolane skeleton can function as thermo- or photoresponsive dyes and are applicable to smart windows and in photolithography. Full article

Here, we successfully synthesized Sr-doped perovskite-type oxides of La_1−xSr_xCo_1−λO_3−δ, “LSX” (x = 0, 0.1, 0.3, 0.5, 0.7), using the glycine-assisted solution combustion method. The effect of strontium doping on the catalyst structure, NO to NO₂ conversion, NO_x adsorption and storage, and NO_x reduction performance were investigated. The physicochemical properties of the catalysts were studied by XRD, SEM-EDS, N₂ adsorption–desorption, FTIR, H₂-TPR, O₂-TPD, and XPS techniques. The NSR performance of LaCoO₃ perovskite was improved after Sr doping. Specifically, the perovskite with 50% of Sr doping (LS5 sample) exhibited excellent NO_x storage capacity within a wide temperature range (200–400 °C), and excellent stability after hydrothermal and sulfur poisoning. It also displayed the highest NO_x adsorption–storage capacity (NAC: 1889 μmol/g; NSC: 1048 μmol/g) at 300 °C. This superior performance of the LS5 catalyst can be attributed to its superior reducibility, better NO oxidation capacity, increased surface Co²⁺ concentration, and, in particular, its generation of more oxygen vacancies. FTIR results further revealed that the LSX catalysts primarily store NO_x through the “nitrate route”. During the lean–rich cycle tests, we observed an average NO_x conversion rate of over 50% in the temperature range of 200–300 °C, with a maximum conversion rate of 61% achieved at 250 °C. Full article

Bipolar Plates (BPPs) play a critical role in Polymer Electrolyte Membrane Water Electrolysers (PEMWEs) for effective hydrogen generation. The performance and longevity of the system can be considerably impacted by choosing the suitable material for these components. Polymer electrolyte membrane water electrolysis technology relies on cost-effective and corrosion-resistant BPPs. Tantalum, niobium, and titanium are low-cost, easy-to-machine materials that have good electrical and thermal conductivity; however, they exhibit low corrosion resistance. Noble metal and metal nitride coatings are usually investigated to minimize corrosion and interfacial contact resistance. Because of its performance-to-cost ratio, Stainless Steel (SS) based materials are among the most popular materials for BPP development. This study recommends material and operating parameters to improve PEMWE systems for sustainable hydrogen production’s efficiency, durability, and economic viability. Full article

Aluminum hydride (AlH₃) has attracted wide attention due to its high gravimetric and volumetric hydrogen capacity. AlH₃ can easily release hydrogen when heated at relatively low temperature. Such high hydrogen density and low dehydrogenation temperature make it one of the most promising high-energy fuels for solid propellants. In particular, AlH₃ as a component of solid propellants may greatly increase the specific impulse of rocket engines. However, AlH₃ exhibits low chemical and thermal stability in an ambient atmosphere. In this paper, the research progress about the synthesis, dehydrogenation thermodynamics, and kinetics, the stabilization of AlH₃ over the past decades are reviewed, with the aim of exploring more a economical synthesis and suitable stabilization methods for large-scale use in solid propellants. Finally, some suggestions regarding future research directions in this filed are proposed. Full article

Distributed throughout the environment are various microorganisms such as bacteria, fungi, parasites, and viruses. Although many are part of the human microbiome, many are pathogenic and cause infections ranging from mild to severe. In recent years, the identification of multidrug-resistant microorganisms has become a serious public health problem. The resulting infections call into question the therapeutic capacity of health systems and lead to approximately 70,000 deaths annually worldwide. The progressive resistance to antibiotics and antifungals has been a major challenge for the medical and pharmaceutical community, requiring the search for new compounds with antimicrobial properties. Several studies have demonstrated the potential of natural and synthesized flavonoids, especially the dimers of these molecules. In this review are presented many examples of dimeric flavonoids that have demonstrated antimicrobial activity against viruses, like influenza and Human Immunodeficiency Virus (HIV), protozoal infections, such as Leishmaniasis and Malaria, fungal infections by Candida albicans and Cryptococcus neoformans, and bacterial infections caused, for example, by Staphylococcus aureus and Escherichia coli. In the pursuit to find potential safe agents for therapy in microbial infections, natural dimeric flavonoids are an option not only for the antimicrobial activity, but also for the low toxicity usually associated with these compounds when compared to classic antimicrobials. Full article

The thionamide antithyroid agents were discovered largely through observations carried out by various researchers in the 1940s that found that sulfhydryl-containing substances were goitrogenic in animals. Prof. Edwin B. Astwood started using these drugs to treat hyperthyroidism. In the current paper, we summarize the development background of these agents and the coordination possibility of 2-thiouracil and its derivatives, as well as the biological activities of some of its complexes. Some of them are used as agents for the treatment of tuberculosis, and arthritis, others have bactericidal and fungicidal activity, the third cytotoxic properties, and could be used to treat various types of cancer. Full article

In this study, the extraction of rare earth elements (REEs) from chloride solutions after leaching REE carbonate concentrate with solutions of the mixtures of P507 (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) and Cyanex 272 (bis(2,4,4-trimethylpentyl)phosphinic acid) (1:1) at various concentrations was experimentally studied. It was shown that the distribution ratios of all REEs decrease with the increasing concentration of these metals in the initial solution, which is associated with the loading of the organic phase. The most significant improvement in the extraction is observed for the heavy group of rare earth elements. The extractability of REEs increases with the increasing atomic number of the element, as is typical for the extraction of these metals with acidic organophosphorus extractants. The data obtained show that the separation factors of adjacent rare earth elements decrease slightly with the increasing concentration of metals in the initial aqueous solution. Increasing the concentration of the extractant mixture does not have a significant effect on the values of the adjacent REE separation factors. The data obtained on the distribution ratios and separation factors made it possible to propose a flow sheet for the separation of rare earth elements with the production of Y, Ho, Tb and Dy. Full article

Metal–organic frameworks (MOFs) represent the largest class of materials among crystalline porous materials ever developed, and have attracted attention as core materials for separation technology. Their extremely uniform pore aperture and nearly unlimited structural and chemical characteristics have attracted great interest and promise for applying MOFs to adsorptive and membrane-based separations. This paper reviews the recent research into and development of MOF membranes for gas separation. Strategies for polycrystalline membranes and mixed-matrix membranes are discussed, with a focus on separation systems involving hydrocarbon separation, CO₂ capture, and H₂ purification. Challenges to and opportunities for the industrial deployment of MOF membranes are also discussed, providing guidance for the design and fabrication of future high-performance membranes. The contributions of the underlying mechanism to separation performance and adopted strategies and membrane-processing technologies for breaking the selectivity/permeability trade-off are discussed. Full article

In recent years, agricultural by-product fillers have been investigated in composites to influence the physical properties of the packaging material, increase biodegradability, and reduce costs. In general, the properties of composites are mainly influenced by the type, amount, and size of fillers. The aim of this study was to characterize potato peel particles as a filler in a poly(lactic acid) (PLA) matrix and to determine the effect of particle size on the physical properties of the composite. Therefore, different fractions of potato peel powder (0–53 μm, 125–250 μm, and 315–500 μm) were incorporated into PLA matrix via compounding and injection-molding. Microscopic analysis of the injection-molded samples revealed that the average particle shape did not differ between the different fractions. Overall, increasing the particle size of potato peel particles resulted in increased stiffness and decreased ductility. The cold crystallization temperature and water vapor transmission rate of the composites were independent of particle size but increased upon the incorporation of potato peel particles. In conclusion, the effect of particle incorporation on packaging-related properties was higher than the effect of using different particle size fractions. This means that potato peel particles, regardless of their particle size distribution, are promising fillers for composites, with the potential to improve biodegradability, maintain some level of protection for the packaged product, and reduce the cost of the composites. Full article

In this work, we present a versatile, rapid, and low-cost manufacturing technique to develop bioceramic scaffolds that could enhance bone tissue regeneration via microwave preparation using a domestic microwave oven. The scaffolds were prepared by combining hydroxyapatite and water glass (sodium trisilicate solution), foamed by using a microwave oven, and then characterized by means of Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Analysis (EDX), mechanical properties, infrared spectroscopy (ATR-FTIR), and a density and stability test in water. Furthermore, in vitro tests were performed to verify the affinity of the scaffold for osteoclast cells. The morphology of the samples showed interconnected pores suitable for promoting tissue regeneration and vascularization, while specific mechanical properties were preserved. The physicochemical characterization and the in vitro tests presented promising results for bone regenerative applications. The scaffolds we obtained exhibited comparable properties to those fabricated using a laboratory microwave oven, including the ability to induce the formation of bone-like tissue in vitro. Full article

Three-dimensional printing (3DP) technologies are characterized as a set of innovative manufacturing techniques that allow for the creation of complex and/or personalized three-dimensional physical objects on the work surface of a 3D printing machine (based on the computer-aided design (CAD) project designs of these parts). Three-dimensional printing techniques are widely used in various areas of knowledge, such as education, engineering, and biomedicine. Polymeric materials are widely used for these applications, mainly due to their desirable workability during part manufacturing, compatibility with other chemical materials, the wide range of polymers with different physical and chemical characteristics, and the possibility for recycling. The development of polymeric drug delivery systems (DDSs) by 3D printing is currently an active field of research, both in academia and industry, given the potential of this technique for medical purposes. In this context, this work reviews potential polymers for the production of drug delivery systems via 3D printing techniques. The demonstrations of the main 3DP techniques used for drug delivery applications include their working principles and advantages and how the technologies develop the final product. In addition, potential synthetic and natural polymers that are currently used in 3DP drug delivery devices are presented and discussed based on recent scientific studies. Full article

The fatty acid (FA) compositions of thirty-nine vegetable oils and fats, including nangai nut, pili nut, shea butter, tamanu oil, baobab, sea buckthorn berry, Brazil nut, grape seed, black seed, evening primrose, passion fruit, milk thistle, sunflower, pumpkin seed, sesame, soybean, flax seed, kukui, red raspberry seed, walnut, chia seed, hemp seed, rosehip, almond, avocado, carrot seed, moringa, apricot kernel, camellia seed, macadamia, olive, marula, argan, castor, jojoba, pomegranate seed, medium-chain triglyceride (MCT) coconut, roasted coconut, canola, and mustard oil, were analyzed using gas chromatography–mass spectrometry (GC-MS). Vegetable oils and fats have different profiles in terms of their fatty acid composition, and their major constituents vary significantly. However, we categorized them into different classes based on the percentages of different fatty acids they contain. The saturated fatty acids, such as palmitic acid and stearic acid, and the unsaturated fatty acids, including oleic acid, linoleic acid, and linolenic acid, are the main categories. Among them, roasted coconut oil contained the greatest amount of saturated fatty acids followed by nangai nut (45.61%). Passion fruit oil contained the largest amount of linoleic acid (66.23%), while chia seed oil had the highest content of linolenic acid (58.25%). Oleic acid was exclusively present in camellia seed oil, constituting 78.57% of its composition. Notably, mustard oil had a significant presence of erucic acid (54.32%), while pomegranate seed oil exclusively contained punicic acid (74.77%). Jojoba oil primarily consisted of (Z)-11-eicosenoic acid (29.55%) and (Z)-docos-13-en-1-ol (27.96%). The major constituent in castor oil was ricinoleic acid (89.89%). Compared with other vegetable oils and fats, pili nut oil contained a significant amount of (E)-FA (20.62%), followed by sea buckthorn berry oil with a content of 9.60%. FA compositions from sources may be problematic in the human diet due to no labeling or the absence of essential components. Therefore, consumers must cast an eye over some essential components consumed in their dietary intake. Full article

In the present study, an insulin-resistant cell model (human hepatocellular carcinoma cell line: HepG2) was chosen to investigate the efficacy of two compound classes and their common molecular motif for glycemic control and insulin sensitization. The two compounds’ classes were flavonoid extracts from Rourea cuspidata and quassinoid extracts from Picrasma crenata. The flavonoid-like hydroxyhydroquinone (HHQ) was synthesized. HepG2 cells were tested in a high-glucose environment (HepG2/IRM) by monitoring ROS activity, the concentration of adenosine triphosphate (ATP), and the measurement of mitochondrial membrane potential (MMP). The expression of forkhead box O1 (FOXO1) protein, which mediates gluconeogenesis and insulin resistance, was also investigated using indirect immunocytochemistry and Western blot techniques. A significant increase in glucose uptake and well-regulated ATP concentrations were observed in the treated cells. The downregulation of FOXO1 expression was seen in cells treated with HHQ and quassinoids in comparison to cells treated with flavonoids. This study provides a pharmacological basis for the application of HHQ, quassinoids from P. crenata, and flavonoids from R. cuspidata in the treatment of metabolic diseases such as type 2 diabetes mellitus. Full article

Rigid polyurethane foams are the better-performing material for the most common insulation purposes, like sandwich panels. Nevertheless, they are highly flammable materials, release toxic gases, and are manufactured from fossil sources. As an alternative, tannin foams are bio-based materials that work as innovative alternatives thanks to their great fire resistance, as well as lower smoke and harmful gases emissions. In the present study, lab-made foams of both materials were compared through morphology, thermal and fire degradation, mechanical properties, and water affinity in order to fill the technological gap between them and their related sandwich panels. It was observed that tannin foams are still relatively inhomogeneous (since formaldehyde was not used) and present a high affinity for water but have higher thermal and fire resistance. The flat compression strength of the polyurethane sandwiches was greater than that of tannin sandwiches (3.61 and 3.09 MPa, respectively) thanks, mainly, to the crosslinking degree difference between the resins. Also, tannin foams presented a lower weight loss (−70.684% lower weight loss in flammability tests than polyurethane foams) and the ability to self-extinguish the flame. Therefore, sandwich panels with tannin foam cores could be successful materials in areas that require protection against fire, such as the building engineering and automotive industries. Full article

Introduction: The antibiofilm activity of silver nanoparticles has been extensively investigated in common bacteria. Metallo-β-lactamase-producing Gram-negative bacteria are hard-to-treat microorganisms with few therapeutic options, and silver nanoparticles were not evaluated on the biofilm of these bacteria. Objectives: The aim of this study was to evaluate the antibiofilm activity of a bone scaffold impregnated with silver nanoparticles in NDM-producing Gram-negative bacilli. Methods: Bone scaffolds from bovine femur were used for the tests and impregnated with silver nanoparticles (50 nm) by physical adsorption. Silver nitrate minimal inhibitory and bactericidal concentrations (MIC and MBC) were performed on NDM-producing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Disc diffusion tests for silver nanoparticles’ susceptibility and the quantification of biofilm production on plate and bone with sessile cell count were performed. Results: The MIC results demonstrated that silver nitrate had an antimicrobial effect on all microorganisms, inactivating the growth of isolates from a concentration of 8 µg/mL. MBC results showed that E. coli 16.211 was the only isolate to present MIC that were different from MBC, with a value of 16 µg/mL. Conclusion: Bone scaffolds impregnated with silver nanoparticles can significantly reduce the biofilm of multidrug-resistant bacteria. This is a strategical material that can be used as bone implant in different clinical conditions. Full article

Several methods have been used to determine the volatile organic compounds emitted by Ophrys orchids. The use of different methods results in incomparable data. Solid-phase microextraction (SPME) has not been used extensively on Ophrys orchids. The main components found in the SPME analysis of the scent in Ophrys orchids were as follows: O. apifera: benzyl benzoate and α-copaene; O. crabronifera subsp. biscutella: pentadecane, heptadecane, and nonadecane; O. bertolonii subsp. bertolonii: pentadecane and heptadecane; O. passionis subsp. garganica: i-propyl palmitate and heptadecane; O. holosericea subsp. apulica: α-copaene, pentadecane, and heptadecane; O. lacaitae: α-copaene, pentadecane, and heptadecane; O. bombyliflora: cyclosativene, pentadecane, and ethyl dodecanoate; O. insectifera: 8-heptadecene and pentadecane; O. lutea: heptadecane and docosane; O. tenthredinifera subsp. neglecta: α-copaene, caryophyllene, and i-propyl palmitate. Full article

As biological material, wood is distinctly affected by to various environmental influences during use. Reductions in durability can come from ultraviolet (UV) radiation, insects, fungi, and microorganisms in both exterior and interior applications. Wood can be easily protected from living organisms via the control of moisture content; however, UV radiation is not so easily managed. Wood components subject to this degradation are damaged and decomposed at a molecular level leading to deterioration of surface quality, especially in visible application areas. A potential remedy to this is using the UV-stabilizing properties of zinc oxide nanoparticles. Zinc oxide nano-dispersions based on propylene glycol (PG) were introduced into the microscopic structure of fir (Abies alba) and beech (Fagus sylvatica) wood by whole-cell impregnation to overcome problems associated with surface coatings. In this work the material uptake of ZnO nano-dispersions in concentrations of 1%, 2%, and 3% w/v were investigated and their effect on the stability of the optical appearance to UV exposure in short-term weathering were evaluated. Untreated reference samples showed significant photo-yellowing. A 1% w/v ZnO dispersion significantly increased the UV stability of treated surfaces. It was found that the uptake of the nano-dispersions was independent of the proportion of ZnO, and that the impregnating agents penetrated fir wood (about 200%) stronger than beech wood (about 70%). Already, a 2% w/v ZnO nano-dispersion led to a saturation of ZnO in the cell structure of the treated wood, for fir as well as beech, and no further ZnO uptake was achieved with 3% w/v nano-dispersions. Scanning electron microscopy shows an agglomeration of ZnO-NP in the cellular pathways impacting penetration, reducing leachability at higher concentrations. Full article

Betel leaves are widely used as herbal medicine in Asia due to their antimicrobial properties. These properties have been attributed to the phenolic compound eugenol and its derivative, hydroxychavicol. Hydroxychavicol has also been shown to inhibit cancer cell proliferation. The main objective of this study was to investigate which structural components of hydroxychavicol are responsible for the antiproliferative property of this compound. Jurkat-E6 cells (JE6) were treated with increasing concentrations (5, 15, and 45 µM) of hydroxychavicol and structural variants of it for 48 h. The results of this study demonstrate that the catechol structure in hydroxychavicol is the structural component that exhibits the highest antiproliferative effect. More specifically, the data show that the six-carbon ring must be aromatic with the two hydroxyl groups attached in an ortho position. Furthermore, this study establishes that the oxygen in the hydroxyl groups has a vital role in the antiproliferative properties of catechol and hydroxychavicol. Full article