Abstract:

Photoinduced charge separation at donor-acceptor composites (active layer material of organic solar cells) is an important step of photoelectric energy conversion. It results in formation of the interfacial charge-transfer state (CTS), which is Coulombically bound electron-hole pair. We developed the mathematical procedure of direct quantification of the electron-hole distance on the basis of time-domain pulse electron paramagnetic resonance data, obtained in electron spin echo (ESE) experiment. For an ensemble of CTSs characterized by distribution of electron-hole distance this procedure derives the average electron-hole distance without numerical simulation of the experimental data, which is a superposition of the oscillating functions, corresponding to CTSs with the certain electron-hole distance. This procedure was tested on model distance distributions, yielding very accurate results. The data for highly efficient organic photovoltaic composite PM6/Y6 were also analyzed; the average electron-hole distance within the CTS and its dependence on temperature were determined. This procedure can be useful for tracing small changes in CTS structure during optimization of the donor-acceptor composite morphology, which is tightly related to photovoltaic efficiency of the composite.

Abstract: New technology has opened opportunities for research and exploration of deep-water ecosystems, highlighting deep-sea coral reefs as a rich source of novel bioactive natural products. During our ongoing investigation of the chemodiversity of the Irish deep-sea and the soft coral Anthothela grandiflora, we report 12 unreported cadinene-like functionalized sesquiterpenes, anthoteibinenes F-Q. The metabolites were isolated using both bioassay- and 1H NMR-guided approaches. 1D/2D NMR spectroscopy and high-resolution mass spectrometry were used for structure elucidation, while a combination of NOESY NMR experiments, GIAO NMR calculations coupled with DP4+ probabilities measures, and ECD comparisons were incorporated to propose relative and absolute configurations of the anthoteibinenes. The metabolites were screened against the Respiratory Syncytial Virus (RSV), ESKAPE pathogens, five Candida albicans strains and one strain of C. auris.

Abstract: Mine tailings are a byproduct of mineral extraction and often pose an environmental challenge due to the contamination of soil and water bodies with dissolved metals. However, this type of waste offers the opportunity for the recovery of valuable metals such as silver (Ag). In the present investigation, an integral analysis of a sample of tailings was carried out, addressing its granulometry, elemental composition, neutralization potential (NP) and acid potential (AP), as well as its mineralogy; for the dissolution of silver from this type of waste. For this purpose, thiourea (CH₄N₂S) was used as a leaching agent due to its low toxicity and potassium oxalate (K₂C₂O₄) as an organic additive to improve the leaching of the silver phases (argentite and polybasite) present in the tailings. The effects of CH₄N₂S and K₂C₂O₄ concentrations, temperature, and pH on the leaching efficiency of silver (Ag), copper (Cu), iron (Fe), and arsenic (As) were systematically studied. The results revealed that the maximum silver dissolution rate reached 90.75% under optimal conditions: 0.2 M L⁻¹ of thiourea, 0.2 M L⁻¹ of potassium oxalate, at 35°C and a pH of 2.

Abstract: The chemical complexity of natural products such as Eugenia punicifolia (Kunth) DC. plant, presents a challenge when extracting and identifying bioactive compounds. This study investigates the impact of different extraction systems and seasonal variations on the chemical profile and pharmacological potential of E. punicifolia leaves using NMR spectroscopy for chemical analysis and canonical correlation analysis (CCA) for bioactivity correlation. Extracts obtained with methanol (M), ethanol (E), methanol:ethanol [1:1 (ME)], and methanol:ethanol:water [3:1:1 (MEW)] were analyzed for antioxidant, antiglycation and antiviral activities. Quantitative ¹H NMR, combined with the PULCON method, was used to quantify phenolic compounds such as quercetin, myricetin, catechin and gallic acid. The results showed that the MEW extract obtained in the rainy season exhibited the highest antioxidant and antiglycation activities, with an AGE inhibition capacity greater than 93%. Furthermore, our results showed that all the extracts were able to inhibit over 94% of the Zika virus (ZIKV) infection in Vero E6 cells. The CCA established strong correlations between the phenolic compounds and bioactivities, identifying gallic acid, catechin, quercetin and myricetin as key chemical markers. This study demonstrates the importance of selecting appropriate extraction systems and considering seasonality to optimize the pharmacological potential of E. punicifolia leaves and highlights the efficacy of NMR in linking chemical composition with bioactivities.

Abstract:

In this study, the possibilities of selective sorption of neodymium and praseodymium ions from a mixture of their solution were studied. For this purpose, based on the obtained results on the dynamics of sorption of each ion separately by industrial hydrogels KU-2-8 (Na+): AV-17-8 (Cl-), interpolymer systems with different molar ratios of cation exchanger and anion exchanger, namely 4:2 and 3:3, respectively, were selected. The choice of these ratios was based on the detection of increased sorption of praseodymium ions from a model solution compared to neodymium ions. The sorption (48 h.) and desorption (72 h.) processes were carried out in two modes: dynamic (with active mixing, speed range 80-150 rpm) and static (without mixing the working solution from which REE were extracted), at room temperature (close to 25° С). According to the obtained results, sorption in the dynamic mode in the ratios of 4:2 and 3:3 does not lead to any selectivity (praseodymium ions were sorbed better than neodymium ions by 3.93% and 2.96% for each ratio). However, a high degree of extraction was noted for both ions: Pr3+ = 99.36%, Nd3+ = 95.67% for the 4:2 system and Pr3+ = 81.33%, Nd3+ =79% for the 3:3 system. In the static mode, the degree of extraction of both metals was significantly lower: for the 4:2 system Pr3+ = 19.33%, Nd3+ = 24%.But, despite this, in the static mode, greater selectivity was observed with respect to one of the metals, namely neodymium. Thus, with a ratio of 4:2, neodymium was sorbed better than praseodymium by 24.16%, and in the 3:3 system by 39.83%. When desorption was carried out from the cationite, a similar picture was also preserved. From here it becomes clear the relevance and necessity of further study of the issue of choosing a technological mode for the sorption of REE from industrial solutions, as well as the creation and selection of similar interpolymer systems that can provide sufficient selectivity in relation to one of the target ions in several extraction cycles.

Abstract: A series of antimicrobial protonated diallylammonium polymers, poly(diallylammonium trifluoroacetate) (PDAATFA), have been synthesized by classical polymerization, using especially elaborated method for preparation of polymers with small molecular weight (MW), and by RAFT polymerization, with different end groups in a range of MW values of (8 – 35)x10^3 g∙mol-1. Cytotoxicity relative to eukaryotic cells (epithelioid lines A-549 and MA-104) and bactericidal activity of the polymers were investigated. The effect of end groups and MW on toxicity and bactericidal activity has been shown. Dependence of the activity and, most of all, cytotoxicity on MW is preserved even at a small difference in MW values (10^4 gxmol-1) in the MW range of (18-35)x10^3 gxmol-1. A clear dependence of the studied properties on the nature of the terminal group has been revealed. Sulfate -O-S(=O)2-O¯ end group has a noticeable effect on the bactericidal efficiency and smaller influence on toxicity, while dithiocarbonyl end group -S-C(=S)-O-CH2-CH3 has significant effect on efficiency and especially toxicity, drastically increasing the second. In a whole, based on results obtained and considering toxicity values obtained for the MA-104 cell line, polymers PDAA of small MW seem to be promising as antimicrobial agents for the creation of new transdermal drugs.

Abstract: Prosthetic joint infections (PJIs) remain a significant challenge, occurring in 1% to 2% of joint arthroplasties and potentially leading to a 20% to 30% mortality rate within 5 years. The primary pathogens responsible for PJIs include Staphylococcus aureus, coagulase-negative staphylococci, and various gram-negative bacteria, typically treated with intravenous antibiotic drugs. However, this conventional approach fails to effectively eradicate biofilms or the microbial burden in affected tissues. As a result, innovative strategies are being explored to enhance the efficacy of infection prevention, through the development of antibacterial coated implants. These coatings are required to demonstrate broad-spectrum antimicrobial activity, minimal local and systemic toxicity, favourable cost-effectiveness, and support for bone healing. In the present review, the analysis of various methodologies for developing antibacterial coatings was performed, emphasizing studies that conducted in vivo tests to advance potential clinical applications. A diversity of techniques employed for the development of coatings incorporating antimicrobial agents, highlight promising avenues for reducing infection-related surgical failures.

Abstract: Nuclear energy, which is considered clean but not renewable energy, currently has a great impact on the energy mix of different countries. In the case of Spain, it implies over 20% of current energy requirements, pointing out the relevance of nuclear power plants. These plants generate different wastes or products (apart from radioactive) that should be managed. For instance, the activated carbon included in filters (which neutralize isotopes in a possible radioactive leakage) must be periodically replaced. These filters have expiration dates that must be respected. Nevertheless, the activated carbon in these filters might present long service lives, as they have not undergone any adsorption process. Consequently, a considerable and recurring amount of activated carbon can be reused in different processes, even in the same nuclear power plant. The aim of this work was to assess the use of activated carbons (previously included in filters to prevent possible radioactive releases in primary circuits) for water treatment derived from the steam cycle of a nuclear power plant. For this purpose, a regeneration process was carried out, measuring the adsorption efficiency by using ethanolamine, proving that factors such as porosity play an important role in the specific usage of activated carbons.

Abstract: This review explores the advancements in additive manufacturing (AM) of biodegradable iron (Fe) and zinc (Zn) alloys, focusing on their potential for medical implants, particularly in vascular and bone applications. Fe alloys are noted for their superior mechanical properties and biocompatibility but exhibit a slow corrosion rate, limiting their biodegradability. Strategies such as alloying with manganese (Mn) and optimizing microstructure via Laser Powder Bed Fusion (LPBF) have been employed to increase Fe´s corrosion rate and mechanical performance. Zn alloys, characterized by moderate biodegradation rates and biocompatible corrosion products, address the limitations of Fe, though their mechanical properties require improvement through alloying and microstructural refinement. LPBF has enabled the fabrication of dense and porous structures for both materials, with energy density optimization playing a critical role in achieving defect-free parts. Fe alloys exhibit higher strength and hardness, while Zn alloys offer better corrosion control and biocompatibility. In vitro and in vivo studies demonstrate promising outcomes for both materials, with Fe alloys excelling in load-bearing applications and Zn alloys in controlled degradation and vascular applications. Despite these advancements, challenges such as localized corrosion, cytotoxicity, and long-term performance require further investigation to fully harness the potential of AM-fabricated Fe and Zn biodegradable implants.

Abstract: The physicomechanical and transport characteristics of heterogeneous anion exchange membranes Ralex AMH-Pes and MA-41, and homogeneous anion exchange membranes AHT and MA-1 in solutions of sodium chloride and succinic acid are studied. It was found that in succinic acid solutions, the concentration dependence of the specific electrical conductivity of anion-exchange membranes has an atypical course compared with the dependence measured in solutions of strong electrolytes. This is due to a change in the pH and ionic composition inside the membrane compared to the external working solution. The concentration dependence of the integral coefficient of diffusion permeability of anion-exchange membranes in succinic acid solution has a decreasing character. This dependence can be explained by the pH shift inside the membrane to a more alkaline region when diluting the external solution, while the equilibrium of the succinic acid dissociation reaction inside the membrane shifts towards the formation of a two-charge succinate anion. With an increase in the proportion of double-charged ions in the membrane phase, an increase in electrostatic forces capable of attracting ions of the opposite charge sign occurs. At the same time, the concentration of co-ions in the membrane phase increases. This effect leads to an increase in the rate of diffusion transfer of the succinic acid molecule with a decrease in its concentration in the working solution.The study of the mass transfer of succinic acid through anion-exchange membranes and the volt-ampere characteristics (CVC) of the anion-exchange membranes AHT and MA-1 showed that succinic acid is capable of being intensively transferred through anion-exchange membranes in the super-limit current mode, as a result of the development of electroconvection at the ion-exchange membrane/diffusion layer interface.