Search Results (270)

Synthetic dyes are widely used in industry; however, their release into the environment without adequate treatment poses serious risks because of their toxicity and adverse effects on human health and aquatic ecosystems. Although conventional methods are effective, they are often costly and have limited sustainability. In this context, ATPSs are proposed as an environmentally friendly alternative aligned with the principles of green chemistry, offering an efficient and cost-effective route. In this study, Tartrazine (Tart), an azo model dye, was used to evaluate the efficiency of an ATPS formed by PEG + salt + H₂O. The effects of the cation and anion nature, PEG molar mass, and pH on Tart partitioning were investigated by determining the partition coefficient of Tart (K_Tart) and the Gibbs free energy of transfer (Δ_trG°). The PEG 1500 + Na₂SO₄ + H₂O ATPS at pH 3.0 exhibited the best performance among the systems evaluated, with a spontaneous transfer process evidenced by Δ_trG° values as low as −21.62 kJ mol⁻¹. The extraction efficiency exceeded 99%, and the ATPS was successfully applied to the removal of Tart from river water and wastewater samples, demonstrating high performance and considerable potential as an alternative technology for the removal of this dye from industrial aqueous solutions. Full article

Black seed (Nigella sativa L., Ranunculaceae) possesses antimicrobial activity due to its bioactive compound, thymoquinone. This study aimed to extract thymoquinone from black seed using an alternative natural deep eutectic solvent (NADES) through an optimization approach. A NADES based on malic acid and choline chloride was employed in this work. The Box–Behnken design was used to investigate the effects of the molar ratio of malic acid to choline chloride, water addition, and ultrasonication time. These variables were varied as follows: the malic acid to choline chloride molar ratio ranged from 2:1 to 4:1, the mass ratio of water to NADES from 0.5:2 to 1.5:2, and the ultrasonication time from 60 to 120 min. The results showed that the malic acid to choline chloride molar ratio, the quadratic term of the malic acid to choline chloride molar ratio, and the quadratic term of ultrasonication time significantly affected thymoquinone extraction. The optimal condition, which yielded the highest thymoquinone concentration, was determined to be a malic acid to choline chloride molar ratio of 4:1, a mass ratio of water to NADES of 1:2, and an ultrasonication time of 60 min. Under these conditions, the thymoquinone concentration was 70.57 ± 5.78 µg/mL, closely aligning with the predicted value. The thymoquinone-rich extract obtained using NADES exhibited antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. In conclusion, NADES serves as an effective alternative solvent for extracting thymoquinone from black seed. Full article

Bimetallic nanoclusters (NCs) containing gold and silver were prepared by template-assisted synthesis using human serum albumin (HSA) via a newly optimized fabrication route at 25 °C. Additionally, following this procedure, we also reproducibly synthesized further Au/Ag NCs, containing a similar Au:Ag ratio, using bovine serum albumin (BSA), lysozyme (LYZ), transferrin (Tf), and gamma-globulin (γG). The aim was to highlight the importance of experimental conditions of the synthesis (e.g., metal ion: protein molar ratio and metal and protein concentrations, as well as synthesis time, temperature, and pH) for the composition, structure, and optical features of the protein-stabilized ultra-small-sized products. Circular dichroism (CD) spectroscopy revealed that the partial unfolding of the stabilizing proteins is primarily caused by the alkaline synthesis environment rather than the nanocluster formation itself. Furthermore, X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma mass spectrometry (ICP-MS) successfully confirmed the presence of mainly metallic (Au⁰) core structures alongside Ag⁰/Ag⁺ species, providing the actual metal-to-protein ratios after purification. As a new result, cytotoxicity of these bimetallic NCs was determined by using doxorubicin-sensitive Colo205 and CCD-19Lu human normal fibroblast cell lines, and their antibacterial activity was also evaluated using four different Gram-positive and Gram-negative bacterial strains. Full article

Chalcones, as flavonoid precursors, are known to have biological importance and vast pharmacological effects. These bioactive molecules have been used in traditional medicine for many years for treatment of various diseases, particularly because of their antitumor activity. The aim of this study was to assess antiproliferative activity of selected hydroxychalcones against six cancer cell lines, derived from various human organs and with varying degrees of aggressiveness and resistance to cytostatics (5637, A-431, UM-SCC-17A, SK-MEL-3, MCC13, A172) in comparison to two noncancerous cell lines (MCF-10A and BALB/3T3). The specific goal of the present study was to assess the influence of 2′-hydroxychalcone, 4-hydroxychalcone and 4′-hydroxychalcone, the compounds with the same molar mass but with different positions of the hydroxyl group, on different stages of apoptosis. Additionally, we aimed to determine the involvement of mitochondria in the initiation of the cell death process. The principal cell line used for validation was Merkel cell carcinoma, a rare type of human skin cancer. The aforementioned compounds were supplemented for 24 and 48 h at several concentrations. In this paper we demonstrate the ability of hydroxychalcones to activate an early stage of apoptosis by exposure of phosphatidylserine on the cell surface with simultaneous changes in mitochondrial membrane. Our results acknowledge and strengthen the prospect of using chalcones for development of new therapeutic strategies in various oncological disease models. Full article

Rosa roxburghii Tratt is recognized as an edible and medicinal plant valued for its nutritional and medicinal properties. Polysaccharides are among its key bioactive constituents. A homogeneous polysaccharide, designated RTW-1, was extracted and purified from the fruit of Rosa roxburghii Tratt. Its molecular mass was determined by HPLC to be 2.16 × 10³ kDa. Monosaccharide composition and methylation analysis showed that RTW-1 is mainly composed of glucose, arabinose, and galacturonic acid in a molar ratio of 1.00:0.48:0.74. The uronic acid content was measured as 55.21%, and the degree of esterification was 58.30%. The glycosidic linkages identified included (→2,3,4)-Manp-(1→, →4)-Arap-(1→, →4)-GalAp-(1→, T-Rhap, →4)-Glcp-(1→, and (→2,3,4)-Xylp-(1→). Shear-thinning behavior was revealed by rheological analysis. At 30 mg/mL, the thixotropic loop area reached 143.8 Pa/s, which was 20 times higher than that at 12 mg/mL. In RAW264.7 macrophages, cell proliferation was promoted by RTW-1. At 80 μg/mL, phagocytic activity was increased by 88%, and NO production was enhanced by 3.1-fold. Concentration-dependent upregulation of TNF-α, IL-6, IL-1β, and IL-10 mRNA expression was observed by qRT-PCR, with maximum increases of 3.2-, 4.1-, 2.8-, and 2.5-fold, respectively. In conclusion, RTW-1 possesses favorable gel-forming and immunostimulatory properties and shows potential for promoting intestinal immune activity, suggesting its promise as a functional food ingredient. Full article

Several studies have shown that supplementation with 100 to 130 mg of 3-nitrooxypropanol (3-NOP)/kg diet acts as a mitigating factor of enteric CH₄ production in ruminants. From an energy perspective, this effect could indicate improved feed energy utilization. Feed additives that reduce the acetate-to-propionate molar ratio and/or CH₄ production generally increase the efficiency of feed energy utilization and can alleviate the negative impact of high ambient heat loads on ruminant productivity. In seeking to test this assumption, the impact of supplementing 3-NOP in growing–finishing diets was evaluated in 24 intact male lambs (31.92 ± 3.77 kg). The experiment lasted 61 days. Treatments consisted of supplementing a total mixed growing–finishing diet (30:70 forage-to-concentrate ratio) with zero or 115 mg 3-NOP/kg diet. Lambs were assigned to 12 pens (two lambs/pen, six replicates per treatment). The temperature–humidity index (THI) during the experiment averaged 83.37 ± 6.4. The inclusion of 3-NOP tended to increase final weight (2.6%, p = 0.06) but increased dry matter intake by 10.6% (p = 0.03), thus decreasing the efficiency of dietary net energy utilization by 2.3% and 3%, respectively (p = 0.04). Lambs fed with 3-NOP showed greater (6.2%, p = 0.04) carcass weight and dressing percentage (3.3%, p = 0.03) without effects on the tissue shoulder composition. Supplemented lambs showed lower gastrointestinal (GIT) fill (9.3%, p = 0.02) and greater (1.3%) empty body weight (EBW, p < 0.01). Visceral organ mass (expressed as g/kg EBW) was not affected by 3-NOP supplementation. It was concluded that supplemental 3-NOP did not improve feed efficiency nor the efficiency of dietary energy utilization, but did improve carcass weight and dressing percentage in lambs fattened under high ambient heat load. The greater carcass weight observed in the present experiment was due mainly to a tendency for a greater final weight (p = 0.06) for 3-NOP lambs, whereas the improvement in dressing percentage was due mainly to a lower (p = 0.02) GIT fill. It is crucial to highlight that this is a pioneering study on the effect of 3-NOP on the productive efficiency of lambs subjected to high ambient heat loads. It is also important to note that enteric methane production was not measured in this experiment. Although the doses used in this experiment have consistently reduced methane production in several studies conducted under favorable climatic conditions, we cannot precisely determine the role of CH₄ production in the dietary net energy efficiency observed in lambs that received 3-NOP. The results presented here provide a basis for future research evaluating the anti-methanogenic and productive responses to the use of 3-NOP under high ambient temperature conditions. Full article

Background/Objectives: Terbium-161 is an interesting and promising theranostic radionuclide, thanks to its decay characteristics (T_1/2 = 6.95 d, E(β)_max = 593 keV, E(β)_av = 154 keV, E(γ) = 74.6 keV (10.2%)). Having similar chemical properties, it is considered as an alternative to currently used ¹⁷⁷Lu. In addition, ¹⁶¹Tb emits a significant amount of conversion and Auger electrons, which contribute to the enhancement of localised therapeutic effect. The aim of this paper is to describe the preparation of ¹⁶¹Tb in quantity and quality relevant for preclinical and early clinical studies and to provide practical notes on the preparation. Methods: No-carrier-added ¹⁶¹Tb has been repeatedly prepared by neutron irradiation of highly enriched ¹⁶⁰Gd targets (up to 98 mg of ¹⁶⁰Gd₂O₃) at nuclear reactor LVR-15 (CV Řež, Czech Republic) in four different irradiation positions. The separation and purification process of ¹⁶¹Tb from the bulk of ¹⁶⁰Gd target was performed by cation exchange chromatography with Dowex 50 W × 8 (H⁺ cycle, 200–400 mesh). Terbium-161 was obtained in ¹⁶¹TbCl₃ form and formulated into 0.1 M HCl solution. The γ-ray spectrometry was used for radionuclide identification and radionuclidic purity and the ICP-MS method for chemical purity measurements and specific activity determination. The DOTA labelling assay was performed, as described by Gracheva et al., providing an assessment of the apparent molar activity of the preparation in terms of its competitive interaction with stable daughter nuclide ¹⁶¹Dy. Results: Irradiations (59.2 h to 421.52 h) of enriched ¹⁶⁰Gd targets with mass ranging from 43.4 to 144.0 mg for ¹⁶⁰Gd(NO₃)₃ and from 12.5 to 98.3 mg for ¹⁶⁰Gd₂O₃ yielded 1.3–23.7 GBq of ¹⁶¹Tb. The separation yields of purified ¹⁶¹Tb varied from 85 to 99%, with the activities of 9.9–22.1 GBq and the highest achieved specific activity of the final product was 4.1 GBq/μg (of Tb). The DOTA chelator was radiolabelled with ¹⁶¹Tb at time points from 2 to 14 days after the end of separation (EOS). Conclusions: Based on our results, we describe practical aspects of terbium production at the laboratory scale with a particular focus on practical aspects and issues arising during the process that may surprise even experienced radiochemists, as lanthanoid separation is not always straightforward, even though it is well-known and has been extensively studied. The preparation of ¹⁶¹Tb in a n.c.a. form proceeds, according to the reported data, with high reproducibility and achieves significant activity levels suitable for both preclinical and clinical investigations by irradiation of highly enriched ¹⁶⁰Gd targets in LVR-15 reactor with subsequent separation and purification of ¹⁶¹Tb on cation exchange resin Dowex 50 W × 8(H⁺). The produced [¹⁶¹Tb]TbCl₃ is employed in subsequent experimental research and development for the labelling of preparations intended for preclinical applications. Full article

The escalating accumulation of pharmaceutical micropollutants in global water systems represents a significant challenge to current circular economy frameworks, highlighting a critical gap in the management of environmental persistence. Although advanced remediation technologies are often proposed to mitigate this crisis, their engineering optimization is frequently compromised by a reliance on empirical approximations rather than precise physicochemical constants. Addressing this fundamental deficit, this study executes a rigorous determination of mass transfer properties for two ubiquitous contaminants: Butylparaben and Triclosan. Utilizing a high-precision electrolytic conductance method under infinite dilution, we investigated transport dynamics across varying temperature gradients (305.15–319.15 K). Experimental data were subjected to advanced mathematical modeling, where the Modified Robinson–Stokes (MRS) quadratic model significantly outperformed classical linear approaches ($R^2>0.98$), accurately capturing non-ideal solute–solvent interactions. The derived limiting molar conductivities facilitated the calculation of infinite dilution diffusion coefficients via the Nernst–Haskell equation, yielding values of $0.99\times {10}^{-8}$ m²/s for Butylparaben and $0.98\times {10}^{-8}$ m²/s for Triclosan. Furthermore, Stokes–Einstein analysis quantified the hydrodynamic radii, elucidating the steric mechanisms governing the sluggish migration of bulky chlorinated ethers compared to single-ring esters. These precise transport parameters are not merely theoretical values; they are essential inputs for developing accurate computational fate models and designing regenerable separation processes, thereby providing the hard physics required to engineer solutions for the perpetual pollution era. Full article

Thymosin β4 (Tβ4) is a highly acidic, intrinsically disordered 43-amino-acid peptide with diverse biological functions, yet its interactions with metal ions remain poorly understood. In this study, we provide the first experimental demonstration that Tβ4 forms discrete Zn²⁺-bound adducts and undergoes Zn²⁺-induced aggregation under physiological pH conditions. Combining zeta potential analysis, dynamic light scattering (DLS), electrospray ionization mass spectrometry (ESI-MS), nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy with elemental mapping (SEM/EDS), we show that Zn(II) binding progressively neutralizes Tβ4’s negative surface charge and triggers a sharp aggregation transition. ESI-MS unambiguously identifies Tβ4/Zn(II) complexes of peptide-to-zinc molar ratio 1:3, while DLS and SEM reveal the formation of compact, low-solubility supramolecular assemblies. NMR measurements support a metal-induced aggregation, confirming the absence of folding upon Zn(II) binding. By quantitatively comparing the experimentally determined critical aggregation concentration with physiologically observed extracellular Zn(II) ranges, we demonstrate that aggregation is unlikely in plasma or basal interstitial environments but may become feasible in Zn-rich microdomains, such as the synaptic cleft, where transient Zn(II) levels can exceed 1 μM. These findings introduce a previously unrecognized dimension of Tβ4 chemistry and suggest that a Zn(II)-mediated supramolecular assembly of Tβ4 could influence peptide behavior in neurological or inflammatory conditions characterized by elevated extracellular Zn(II). This work establishes a foundational biochemical framework for future studies aimed at elucidating the biological implications of Tβ4/Zn(II) complexation and aggregation in vivo. Full article

Lanthanide-based single-molecule magnets are promising candidates for potential applications. Their magnetism is governed by ligand-field splittings, which may require up to 27 ligand-field parameters for accurate modeling. Determining these parameters reliably from measured data is a major challenge, for which machine learning approaches offer promising solutions. We provide an overview of these approaches and present our perspective on addressing the inverse problem relating experimental data to ligand-field parameters. Previously, a machine learning architecture combining a variational autoencoder (VAE) and an invertible neural network (INN) showed promise for analyzing temperature-dependent magnetic susceptibility data. In this work, the VAE-INN model is extended through data augmentation to enhance its tolerance to common experimental inaccuracies. Focusing on second-order ligand-field parameters, diamagnetic and molar-mass errors are incorporated by augmenting the training dataset with experimentally motivated error distributions. Tests on simulated experimental susceptibility curves demonstrate substantially improved prediction accuracy and robustness when the distributions correspond to realistic error ranges. When applied to the experimental susceptibility curve of the complex ${\mathrm{Al}}_2^{\mathrm{III}}$${\mathrm{Er}}_2^{\mathrm{III}}$, the augmented VAE–INN recovers ligand-field solutions consistent with least-squares benchmarks. The proposed data augmentation thus overcomes a key limitation, bringing the ML approach closer to practical use for higher-order ligand-field parameters. Full article

Oligocarbonate diols (OCD) require tedious and time-consuming synthesis procedures. The most common ones use dimethyl carbonate or alkylene carbonate as starting materials. Considering the preparation of small batches of oligomerols with an atypical structure, this methodology is not convenient. Therefore, we developed a simple way to obtain OCDs and oligo(urethane-carbonate) diols (OUCDs) containing aliphatic, cycloaliphatic, aromatic or oxyethylene units based on commercially available OCDs (ETERNACOLL, UBE). The process was conducted in two stages combining transesterification/transurethanization and polycondensation reactions. It resulted in novel OCDs and OUCDs with an irregular structure. Their composition was characterized using FT-IR, NMR, and MALDI-TOF techniques. The hydroxyl values were determined by potentiometric titration. The numerical average molar masses of the oligomerols ranged from approx. 1000 to 3200 g/mol, making them attractive materials for the preparation of a variety of polyurethane products. Thanks to the presence of carbonate moieties that are resistant to hydrolytic and oxidative degradation, poly(carbonate-urethane)s could find applications as coatings, thermoplastic elastomers, and biomaterials. The influence of the structural variations of the oligomerols on the properties of polyurethanes is now under investigation. Full article

The increasing atmospheric concentration of carbon dioxide (CO₂) poses a critical threat to global climate stability, highlighting the need for efficient carbon capture technologies. While amine-based solvents such as monoethanolamine (MEA) are widely used for industrial CO₂ capture, they are subject to limitations such as high energy requirements for regeneration, solvent degradation, and environmental concerns. This study investigates potassium carbonate/bicarbonate system as an alternative solution for CO₂ absorption. The absorption mechanism and reaction kinetics of potassium carbonate in the presence of bicarbonates were reviewed. A rate-based model was developed in Aspen Plus, using literature kinetics, to simulate CO₂ absorption using 20 wt% potassium carbonate (K₂CO₃) solution with 10% carbonate-to-bicarbonate conversion under different industrial conditions. Three flue gas compositions were evaluated: cement industry, biomass combustion, and anaerobic digestion, each at 3000 m³/h flow rate. The simulation was conducted to determine minimum column height and solvent loading requirements with a target output of 90% CO₂ removal from the gas streams. Results demonstrated that potassium carbonate systems successfully achieved the target removal efficiency across all scenarios. Column heights ranged from 18 to 25 m, with molar K₂CO₃/CO₂ ratios between 1.41 and 4.00. The biomass combustion scenario proved most favorable due to lower CO₂ concentration and effective heat integration. While requiring higher column heights (18–25 m) compared to MEA systems (6–12 m) and greater solvent mass flow rates, potassium carbonate demonstrated technical feasibility for CO₂ capture. The findings of this study provide a foundation for technoeconomic evaluation of potassium carbonate systems versus amine-based technologies for industrial carbon capture applications. Full article

Today, PHB and its copolymers—potential plastic substitutes—are produced by fermenting sugar, which is not scalable to the volumes of plastic consumption. PHB from CH₄ can offer a sustainable process route, with CH₄ potentially produced from a variety of waste biomass streams through anaerobic digestion, gasification, and methanation. The high molar mass (M_w) of PHB is a key determinant of its mechanical properties, and strain, culture conditions and downstream processing influence it. In this work, the strain Methylocystis sp. GB 25 (DSMZ 7674) was grown on natural gas as the sole carbon and energy source and air (1:1) in a loop reactor with 350 L active fermentation volume, at 35 °C and ambient pressure. After two days of continuous growth, the bacteria were limited in P and N for 1, 2, and 2.5 days to determine the optimal conditions for PHB accumulation and the highest Mw as the target. The biomass was then centrifuged and spray-dried. For downstream processing, chloroform solvent extraction and selected enzymatic treatment were deployed, yielding ~40% PHB from the biomass. The PHB obtained by solvent extraction exhibited high average weight molar masses of M_w ~1.1–1.5 × 10⁶ g mol⁻¹. The highest M_w was obtained after one day of limitation, whereas enzyme treatment resulted in partially degraded PHB. Cold chloroform maceration, interesting due to energy savings, did not achieve sufficient extraction efficiency because it was unable to extract high-molar-mass PHB fractions. The extracted PHB has a high molar mass, more than double that of standard commercial PHB, and was characterized by DSC, which showed a high degree of crystallinity of up to 70% with a melting temperature of close to 180 °C. Mechanical tensile properties measurements, as well as dynamic mechanical thermal analysis (DMTA), were performed. Degradation of the PHB by enzymes was also determined. Methanotrophic PHB is a promising bioplastics material. The high M_w can limit and delay polymer degradation in practical processing steps, making the material more versatile and robust. Full article

Herein, we report the synthesis via controlled reversible addition-fragmentation chain transfer (RAFT) polymerization of amphiphilic 2-vinylpyridine-b-styrene (2VPy-b-Sty) diblock copolymers of high molar masses (range: 52,100–304,000 g mol⁻¹) and various compositions (range: 2VP content 11.6–59.2 mol%) and their use for the fabrication of nanoporous membranes. The successful synthesis of the amphiphilic diblock copolymers was confirmed through the characterization of their molar masses, molar mass distribution, and composition using GPC and ¹H-NMR spectroscopy, respectively. Subsequently, membranes of the diblock copolymers were fabricated following the “phase inversion” technique. The resulting membranes were characterized via scanning electron microscopy which revealed the presence of sphere percolation networks morphology for all diblock copolymers with M_n ranging from 120 to 300 kDa and 2VPy content between 10 and 15 mol% at the optimal conditions. Afterward, the developed membranes were evaluated in terms of their permeability towards water and in terms of their ability to retain two different microorganisms, namely, Enterococcus faecalis and Escherichia coli, that are known to be harmful to human health. The experimental water flux for a membrane with pore size around 60 nm was equal to 31,400 L h⁻¹ m² and expectedly decreased with the decrease in membrane pore diameter. The retention ability of membranes for Enterococcus faecalis and Escherichia coli was higher than 90%. In particular, the retention ability for Enterococcus faecalis was equal to 98.9% and for Escherichia coli was 91.4%. The toxicity of the produced membrane was also determined, and the measured value was relatively low, at 17%. Full article

Bentonite is the most widely used raw material for producing organoclays, which have numerous industrial and environmental applications. Due to their hydrophobicity, high swelling, and strong affinity for organic compounds, organoclays are effective in removing organic solvents from contaminated water originating from pipeline leaks, oil spills, traffic accidents, and industrial discharges. Such contamination not only degrades water quality but also forms surface films that hinder oxygen transfer, threatening aquatic ecosystems. In this study, two sodium bentonites with different specific surface areas (30 and 50 m²/g) were modified with three quaternary ammonium salts of varying molar masses and alkyl chain lengths (Sun, Arq, and Arm) to evaluate their performance in organic solvent sorption (gasoline, diesel, and kerosene). The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM), and swelling capacity and sorption efficiency. The swelling capacity was determined according to ASTM D5890-19 (Foster method) using gasoline, diesel, kerosene, toluene, and xylene, while the sorption efficiency was assessed following ASTM F726-17 in gasoline, diesel, and kerosene, chosen due to their high potential for water contamination and frequent occurrence in oil spill and leakage scenarios. These solvents also differ in polarity and aromatic content, providing a relevant model for hydrocarbon mixtures commonly found in the environment. Results showed that the interaction between the clay and the surfactant depended strongly on the modifier’s chemical structure. The sorption capacity increased with greater interlayer expansion, surfactant molar mass, and specific surface area of the clay. Among all samples, the Arm-modified natural bentonite (VLArm) exhibited the best performance, with adsorption capacities of up to 6 g/g for diesel, 5 g/g for gasoline, and 5 g/g for kerosene. These values exceeded most previously reported organoclays. These findings demonstrate that optimizing the combination of clay properties and surfactant chemistry can yield highly efficient, low-cost organoclays for environmental remediation of organic contaminants. Full article