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The non-steroid anti-inflammatory drug ketoprofen (KP) as a model molecule is encapsulated in different poly(lactide-co-glycolide) (PLGA) nanostructured particles, using Tween20 (TWEEN) and Pluronic F127 (PLUR) as stabilizers to demonstrate the design of a biocompatible colloidal carrier particles with highly controllable drug release feature. Based on TEM images the formation of well-defined core-shell structure is highly favorable using nanoprecipitation method. Stabile polymer-based colloids with ~200–210 nm hydrodynamic diameter can be formed by successful optimization of the KP concentration with the right choice of stabilizer. Encapsulation efficiency (EE%) of 14–18% can be achieved. We clearly confirmed that the molecular weight of the stabilizer thus its structure greatly controls the drug release from the PLGA carrier particles. It can be determined that ~20% and ~70% retention is available with the use of PLUR and TWEEN, respectively. This measurable difference can be explained by the fact that the non-ionic PLUR polymer provides a steric stabilization of the carrier particles in the form of a loose shell, while the adsorption of the non-ionic biocompatible TWEEN surfactant results in a more compact and well-ordered shell around the PLGA particles. In addition, the release property can be further tuned by decreasing the hydrophilicity of PLGA by changing the monomer ratio in the range of ~20–60% (PLUR) and 70–90% (TWEEN).

In the current work, we first present a simple synthesis method for the preparation of novel Vitamin-B1-stabilized few-atomic gold nanoclusters with few atomic layers. The formed nanostructure contains ca. eight Au atoms and shows intensive blue emissions at 450 nm. The absolute quantum yield is 3%. The average lifetime is in the nanosecond range and three main components are separated and assigned to the metal–metal and ligand–metal charge transfers. Based on the structural characterization, the formed clusters contain Au in zero oxidation state, and Vitamin B1 stabilizes the metal cores via the coordination of pyrimidine-N. The antioxidant property of the Au nanoclusters is more prominent than that of the pure Vitamin B1, which is confirmed by two different colorimetric assays. For the investigation into their potential bioactivity, interactions with bovine serum albumin were carried out and quantified. The determined stoichiometry indicates a self-catalyzed binding, which is almost the same value based on the fluorometric and calorimetric measurements. The calculated thermodynamic parameters verify the spontaneous bond of the clusters along the protein chain by hydrogen bonds and electrostatic interactions.

There are a number of uncertainties regarding plasma protein binding and blood distribution of the active drugs favipiravir (FAVI), molnupiravir (MOLNU) and imatinib (IMA), which were recently proposed as therapeutics for the treatment of COVID-19 disease. Therefore, proton dissociation processes, solubility, lipophilicity, and serum protein binding of these three substances were investigated in detail. The drugs display various degrees of lipophilicity at gastric (pH 2.0) and blood pH (pH 7.4). The determined pKa values explain well the changes in lipophilic character of the respective compounds. The serum protein binding was studied by membrane ultrafiltration, frontal analysis capillary electrophoresis, steady-state fluorometry, and fluorescence anisotropy techniques. The studies revealed that the ester bond in MOLNU is hydrolyzed by protein constituents of blood serum. Molnupiravir and its hydrolyzed form do not bind considerably to blood proteins. Likewise, FAVI does not bind to human serum albumin (HSA) and α1-acid glycoprotein (AGP) and shows relatively weak binding to the protein fraction of whole blood serum. Imatinib binds to AGP with high affinity (logK′ = 5.8–6.0), while its binding to HSA is much weaker (logK′ ≤ 4.0). The computed constants were used to model the distribution of IMA in blood plasma under physiological and ‘acute-phase’ conditions as well.

Cancer chemotherapeutics usually have serious side effects. Targeting the special properties of cancer and activation of the anticancer drug in the tumor microenvironment in situ may decrease the intensity of the side effects and improve the efficacy of therapy. In this study, half-sandwich Rh complexes are introduced, which may be activated at the acidic, extracellular pH of the tumor tissue. The synthesis and aqueous stability of mixed-ligand complexes with a general formula of [Rh(η5-Cp*)(N,N/O)(N)]2+/+ are reported, where (N,N/O) indicates bidentate 8-quinolate, ethylenediamine and 1,10-phenanthroline and (N) represents the releasable monodentate ligand with a nitrogen donor atom. UV-visible spectrophotometry, 1H NMR, and pH-potentiometry were used to determine the protonation constants of the monodentate ligands, the proton dissociation constants of the coordinated water molecules in the aqua complexes, and the formation constants of the mixed-ligand complexes. The obtained data were compared to those of the analogous Ru(η6-p-cymene) complexes. The developed mixed-ligand complexes were tested in drug-sensitive and resistant colon cancer cell lines (Colo205 and Colo320, respectively) and in four bacterial strains (Gram-positive and Gram-negative, drug-sensitive, and resistant) at different pH values (5–8). The mixed-ligand complexes with 1-methylimidazole displayed sufficient stability at pH 7.4, and their activation was found in cancer cells with decreasing pH; moreover, the mixed-ligand complexes demonstrated antimicrobial activity in Gram-positive and Gram-negative bacteria, including the resistant MRSA strain. This study proved the viability of incorporating releasable monodentate ligands into mixed-ligand half-sandwich complexes, which is supported by the biological assays.

Anionic surfactants, such as sodium linear alkylbenzene sulfonates (NaLAS), are utilized in various fields, including industry, household, and agriculture. The efficiency of their use in aqueous environments is significantly affected by the presence of cations, Ca2+ and Mg2+ in particular, as they can decrease the concentration of the surfactant due to precipitation. To understand cation–sulfonate interactions better, we study both NaLAS colloidal solutions in the presence of CaCl2 and precipitates forming at higher salt concentrations. Upon addition of CaCl2, we find the surface tension and critical micelle concentration of NaLAS to decrease significantly, in line with earlier findings for alkylbenzylsulfonates in the presence of divalent cations. Strikingly, an increase in the surface tension is discernible above 0.6 g L–1 NaLAS, accompanied by the decrease of apparent micelle sizes, which in turn gives rise to transparent systems. Thus, there appears to be a second critical concentration indicating another micellar equilibrium. Furthermore, the maximum salt tolerance of the surfactant is 0.1 g L–1 Ca2+, above which rapid precipitation occurs yielding sparingly soluble CaLAS2∙2H2O.

Electrospun is a unique class of porous and heterogeneous materials with multi-length-scales constituents that offer a rich variety of surface functionalities to serve a host of applications. Upscaling the electrospun materials from the laboratory to the industry is often limited by the lack of understanding of their mechanical properties. Herein, we developed a theoretical framework to predict the elastic constants of the electrospun mats that hinges on the concept of elastic properties of constituent fibers, three-dimensional (3D) alignment of fibers, and local fiber curvature. Enabled by continuum-based micromechanical approaches, this framework successfully pre-dicted the elastic moduli regardless of bead-string morphology and local architectural heterogeneities present within the electrospun mats. The 3D fiber orientation distribution obtained using X-ray nano-computed tomography (nanoCT) analysis served as a key input for the validation of the analytical model. In general, the predicted elastic moduli are in reasonably good agreement with the experimental data of randomly oriented and preferentially aligned polylactic acid (PLA)-based electrospun mats. To demonstrate our analytical model's versatility and reliability, another set of PA6(3)-based electrospun mats has been chosen from the literature for validation purposes. The parametric analysis has been performed to provide a roadmap to improve the elastic moduli of electrospun mats and justify the assumed values of some of the key attributes.

We have studied the calcium phosphate precipitation reaction by producing chemical gardens in a controlled manner using a three-dimensional flow-driven technique. The injection of the phosphate containing solution into the calcium ion reservoir has resulted in structures varying from membranes to crystals. Dynamical phase diagrams are constructed by varying chemical composition and flow rates from which three different growth mechanisms have been revealed. The microstructural analysis by scanning electron microscopy and powder X-ray diffraction confirmed the morpho-logical transition from membrane tubes to crystalline branches upon decreasing pH.

It is well established that cationic peptides can enter cells following attachment to polyanionic membrane components. We report that the basic nuclear localization signal (NLS) of the NF-κB p50 subunit is internalized via lipid raft-dependent endocytosis mediated by heparan sulfate proteoglycans and exerts significant NF-κB inhibitory activities both in vitro and in vivo. In vitro uptake experiments revealed that the p50 NLS peptide (CYVQRKRQKLMP) enters the cytoplasm and accumulates in the nucleus at 37 °C. Depleting cellular ATP pools or decreasing temperature to 4 °C abolished peptide internalization, confirming the active, energy-dependent endocytic uptake. Co-incubation with heparan sulfate or replacing the peptide’s basic residues with glycines markedly reduced the intracellular entry of the p50 NLS, referring to the role of polyanionic cell-surface proteoglycans in internalization. Furthermore, treatment with methyl-β-cyclodextrin greatly inhibited the peptide’s membrane translocation. Overexpression of the isoforms of the syndecan family of transmembrane proteoglycans, especially syndecan-4, increased the cellular internalization of the NLS, suggesting syndecans’ involvement in the peptide’s cellular uptake. In vitro , p50 NLS reduced NF-κB activity in TNF-α-induced L929 fibroblasts and LPS-stimulated RAW 264.7 macrophages. TNF-α-induced ICAM-1 expression of HMEC-1 human endothelial cells could also be inhibited by the peptide. Fifteen minutes after its intraperitoneal injection, the peptide rapidly entered the cells of the pancreas, an organ with marked syndecan-4 expression. In an acute pancreatitis model, an inflammatory disorder triggered by the activation of stress-responsive transcription factors like NF-κB, administration of the p50 NLS peptide reduced the severity of pancreatic inflammation by blocking NF-κB transcription activity and ameliorating the examined laboratory and histological markers of pancreatitis.

Tailoring the hydrophobicity of the cathode gas diffusion electrode mitigates flooding in parallel with enhancing the selectivity of the electrochemical carbon monoxide reduction reaction.

Certain industrially relevant performance metrics of CO2 electrolyzers have already been approached in recent years. The energy efficiency of CO2 electrolyzers, however, is yet to be improved, and the reasons behind performance fading must be uncovered. The performance of the electrolyzer cells is strongly affected by their components, among which the gas diffusion electrode is one of the most critical elements. To understand which parameters of the gas diffusion layers (GDLs) affect the cell performance the most, we compared commercially available GDLs in the electrochemical reduction of CO2 to CO, under identical, fully controlled experimental conditions. By systematically screening the most frequently used GDLs and their counterparts differing in only one parameter, we tested the influence of the microporous layer, the polytetrafluoroethylene content, the thickness, and the orientation of the carbon fibers of the GDLs. The electrochemical results were correlated to different physical/chemical parameters of the GDLs, such as their hydrophobicity and surface cracking.

ACS materials letters 5(2), 565 - 573 (2023). doi:10.1021/acsmaterialslett.2c00580, Application of antioxidant enzymes in medical or industrial processes is limited due to their high sensitivity to environmental conditions. Incorporation of such enzymes in nanostructures provides a promising route to obtain highly efficient and robust biocatalytic system to scavenge reactive oxygen species (ROS). Here, this question was addressed by confinement of superoxide dismutase (SOD), horseradish peroxidase (HRP), and catalase (CAT) enzymes into nanostructures containing polyelectrolyte building blocks (alginate (Alg) and trimethyl chitosan (TMC)) and delaminated layered double hydroxide (dLDH) nanoparticle support. The nanocomposite possessed excellent structural and colloidal stability, while antioxidant tests revealed that the enzymes remained active upon immobilization and the developed composite greatly reduced intracellular oxidative stress in two-dimensional cell cultures. Moreover, it effectively prevented hydrogen peroxide-induced double stranded DNA breaks, which is a common consequence of oxidative stress. The results provide important tools to design complex nanostructures with multienzymatic antioxidant activities for ROS scavenging., Published by ACS Publications, Washington, DC

The beneficial redox properties of ferrocene-based polymers have been utilized during in situ preparation of metallic nanoparticles, while such redox features also indicate great promise in applications as free radical...

The present study demonstrates the importance of converting signal intensity maps of organic tissues collected by laser-induced breakdown spectroscopy (LIBS) to elemental concentration maps and also proposes a methodology based on machine learning for its execution. The proposed methodology employs matrix-matched external calibration supported by a pixel-by-pixel automatic matrix (tissue type) recognition performed by linear discriminant analysis of the spatially resolved LIBS hyperspectral data set. On a swine (porcine) brain sample, we successfully performed this matrix recognition with an accuracy of 98% for the grey and white matter and we converted a LIBS intensity map of a tissue sample to a correct concentration map for the elements Na, K and Mg. Found concentrations in the grey and white matter agreed the element concentrations published in the literature and our reference measurements. Our results revealed that the actual concentration distribution in tissues can be quite different from what is suggested by the LIBS signal intensity map, therefore this conversion is always suggested to be performed if an accurate concentration distribution is to be assessed.

This study investigates the enhancement of dairy wastewater treatment using chemical and physical pre-treatments coupled with membrane separation techniques to reduce membrane fouling. Two mathematical models, namely the Hermia and resistance-in-series module, were utilized to comprehend the mechanisms of ultrafiltration (UF) membrane fouling. The predominant fouling mechanism was identified by fitting experimental data into four models. The study calculated and compared permeate flux, membrane rejection, and membrane reversible and irreversible resistance values. The gas formation was also evaluated as a post-treatment. The results showed that the pre-treatments improved UF efficiency for flux, retention, and resistance values compared to the control. Chemical pre-treatment was identified as the most effective approach to improve filtration efficiency. Physical treatments after microfiltration (MF) and UF showed better fluxes, retention, and resistance results than ultrasonic pre-treatment followed by UF. The efficacy of a three-dimensionally printed (3DP) turbulence promoter was also examined to mitigate membrane fouling. The integration of the 3DP turbulence promoter enhanced hydrodynamic conditions and increased the shear rate on the membrane surface, shortening filtration time and increasing permeate flux values. This study provides valuable insights into optimizing dairy wastewater treatment and membrane separation techniques, which can have significant implications for sustainable water resource management. The present outcomes clearly recommend the application of hybrid pre-, main- and post-treatments coupled with module-integrated turbulence promoters in dairy wastewater ultrafiltration membrane modules to increase membrane separation efficiencies.

A series of four indolo[2,3-e]benzazocines HL1–HL4 and two indolo[2,3-f]benzazonines HL5–and HL6, as well as their respective copper(II) complexes 1–6 were synthesized and characterized by 1H and 13C NMR spectroscopy, ESI...

This publication presents the synthesis of core–shell nanoparticles, where the core was Ni, and the shell was a Ag–Ni nano alloy. The synthesis was based on the reduction of Ni and Ag ions with sodium borohydride in the presence of trisodium citrate as a stabilizer. In order to determine the phase composition of the obtained nanoparticles, an XRD study was performed, and in order to identify the oxidation states of the nanoparticle components, an XPS spectroscopic study was performed. The composition and shape of the particles were determined using the HR-TEM EDS test. The obtained nanoparticles had a size of 11 nm. The research on catalytic properties was carried out in the model methylene blue reduction system. The investigation of the catalytic activity of colloids was carried out with the use of UV–Vis spectrophotometry. The Ag–Ni alloy was about ten times more active than were pure silver nanoparticles of a similar size.

Glucose-to-fructose isomerization is the key process in the reaction sequence that can lead to the total conversion of biomass into valuable fine chemicals. However, it is challenging to find an...

Thin films of tin (II) sulfide (SnS) were deposited onto a 500 µm thick copper substrate by a chemical bath method. The effect of sodium (Na) doping in these films was studied. The synthesis of the films was performed at temperatures of 60, 70, and 80 °C for 5 min. The microstructure of the SnS films analyzed by scanning electron microscopy (SEM) showed a compact morphology of the films deposited at 80 °C. The edges of the SnS grains were rounded off with the addition of a commercial surfactant. The thickness of different SnS layers deposited on the copper substrate was found to be 230 nm from spectroscopic ellipsometry and cross-section analysis using SEM. The deposition parameters such as temperature, surfactant addition, and sodium doping time did not affect the thickness of the layers. From the X-ray diffraction (XRD) analysis, the size of the SnS crystallites was found to be around 44 nm. Depending on the process conditions, Na doping affects the size of the crystallites in different ways. A study of the conductivity of SnS films provides a specific conductivity value of 0.3 S. The energy dispersive analysis of X-rays (EDAX) equipped with the SEM revealed the Sn:S stoichiometry of the film to be 1:1, which was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. The determined band-gap of SnS is equal to 1.27 eV and is in good agreement with the literature data.

Carbon dots (CDs) are zero-dimensional nanomaterials composed of carbon and surface groups attached to their surface. CDs have a size smaller than 10 nm and have potential applications in different fields such as metal ion detection, photodegradation of pollutants, and bio-imaging, in this review, the capabilities of CDs in metal ion detection will be described. Quantum confinement is generally viewed as the key factor contributing to the uniqueness of CDs characteristics due to their small size and the lack of attention on the surface functional groups and their roles is given, however, in this review paper, the focus will be on the functional group and the composition of CDs. The surface functional groups depend on two parameters: (i) the oxidation of precursors and (ii) their composition. The mechanism of metal ion detection is still being studied and is not fully understood. This review article emphasizes the current development and progress of CDs, focusing on metal ion detection based on a new perspective.

The assembly of colloidal hyaluronic acid (HyA, as a polysaccharide) based hydrogel particles in an aqueous medium is characterized in the present paper, with an emphasis on the particular case of nanohydrogels formed by surfactant-neutralized polysaccharide networks. The structural changes and particle formation process of polysaccharide- and cationic-surfactant-containing systems were induced by the charge neutralization ability and the hydrophobic interactions of cetyltrimethylammonium bromide (CTAB) under different conditions. Based on the rheological, light scattering, ζ-potential, turbidity, and charge titration measurements, it can be concluded that the preparation of the HyA-CTAB particles can be greatly controlled. The results indicate that more available negative charges can be detected on the polymer chain at smaller initial amounts of HyA (cHyA < 0.10 mg/mL), where a molecular solution can be formed. The change in the pH has a negligible effect on the formation process (particle aggregation appears at nCTAB/nHyA,monomer~1.0 in every case), while the temperature dependence of the critical micelle concentration (c.m.c.) of CTAB determines the complete neutralization of the forming nanohydrogels. The results of our measurements confirm that after the appearance of stable colloidal particles, a structural change and aggregation of the polymer particles take place, and finally the complete charge neutralization of the system occurs.

The radical scavenging activity of three molecular antioxidants (trolox, rutin and ellagic acid) was investigated in different solvents with and without added polymer-based colloidal particles (SL-IP-2). Rutin and ellagic acid showed poor solubility in water, preventing the accurate measurement of the effective antioxidant concentration values, which were determined in ethanol/water (EtOH/H2O) mixtures. The presence of trolox and rutin changed neither the surface charge properties nor the size of SL-IP-2 in these solvents, while significant adsorption on SL-IP-2 was observed for ellagic acid leading to overcharging and rapid particle aggregation at appropriately high antioxidant concentrations in EtOH/H2O. The differences in the radical scavenging capacity of trolox and ellagic acid that was observed in homogeneous solutions using water or EtOH/H2O as solvents vanished in the presence of the particles. Rutin lost its activity after addition of SL-IP-2 due to the larger molecular size and lower exposure of the functional groups to the substrate upon interaction with the particles. The obtained results shed light on the importance of the type of solvent and particle–antioxidant interfacial effects on the radical decomposition ability of molecular antioxidants, which is of crucial importance in industrial processes involving heterogeneous systems.

A series of novel estradiol-based salicylaldehyde (thio)semicarbazones ((T)SCs) bearing (O,N,S) and (O,N,O) donor sets and their Cu(II) complexes were developed and characterized in detail by 1H and ¹³C nuclear magnetic resonance spectroscopy, UV–visible and electron paramagnetic resonance spectroscopy, electrospray ionization mass spectrometry and elemental analysis. The structure of the Cu(II)-estradiol-semicarbazone complex was revealed by X-ray crystallography. Proton dissociation constants of the ligands and stability constants of the metal complexes were determined in 30% (v/v) DMSO/H2O. Estradiol-(T)SCs form mono-ligand complexes with Cu(II) ions and exhibit high stability with the exception of estradiol-SC. The Cu(II) complexes of estradiol-TSC and its N,N-dimethyl derivative displayed the highest cytotoxicity among the tested compounds in MCF-7, MCF-7 KCR, DU-145, and A549 cancer cells. The complexes do not damage DNA according to both in vitro cell-free and cellular assays. All the Cu(II)-TSC complexes revealed significant activity against the Gram-positive Staphylococcus aureus bacteria strain. Estradiol-TSCs showed efficient antioxidant activity, which was decreased by complexation with Cu(II) ions. The exchange of estrone moiety to estradiol did not result in significant changes to physico-chemical and biological properties.

Synephrine has been used to promote weight loss; however, its safety and efficacy have not been fully established. The goals of our study were to give an overview of the safety and efficacy of p-synephrine, to systematically evaluate its efficacy regarding weight loss and to assess its safety, focusing on its cardiovascular side effects in a meta-analysis. PubMed, the Cochrane Library, Web of Science and Embase were searched for relevant studies. Only placebo-controlled, human clinical trials with synephrine intervention were included in the meta-analysis. The meta-analysis was reported according to the PRISMA guidelines using the PICOS format and taking into account the CONSORT recommendations. Altogether, 18 articles were included in the meta-analysis. Both systolic and diastolic blood pressure (DBP) increased significantly after prolonged use (6.37 mmHg, 95% CI: 1.02–11.72, p = 0.02 and 4.33 mmHg, 95% CI: 0.48–8.18, p = 0.03, respectively). The weight loss in the synephrine group was non-significant after prolonged treatment, and it did not influence body composition parameters. Based on the analyzed clinical studies, synephrine tends to raise blood pressure and heart rate, and there is no evidence that synephrine can facilitate weight loss. Further studies are needed to confirm evidence of its safety and efficacy.

A wide variety of additives are used to improve specific characteristics of the final polymeric product. Antioxidant additives (AAs) can prevent oxidative stress and thus the damage of polymeric materials. In this work, the antioxidant potential and thus the applicability of Santowhite (SW) as synthetic and ascorbic acid (Asc) as natural AAs were explored by using computational tools. Two density functional theory (DFT) methods, M05-2X and M06-2X, have been applied in combination with the 6-311++G(2d,2p) basis set in gas phase. Three antioxidant mechanisms have been considered: hydrogen atom transfer (HAT), single electron transfer-proton transfer (SET-PT), and sequential proton loss electron transfer (SPLET). Bond dissociation enthalpy (BDE), ionization potential (IP), proton dissociation enthalpy (PDE), proton affinity (PA), and electron transfer enthalpy (ETE) have been computed for each potential hydrogen donor site. The results indicate that the antioxidant potential of Asc is higher than SW. Furthermore, some of the C-H bonds, depending on their position in the structures, are potent radical scavengers, but O-H groups are more prone to donate H-atoms to free radicals. Nonetheless, both additives can be potentially applied to safeguard common polymers and prohibit oxidative stress-induced material deterioration.

Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods—orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus and Mochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon possesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning. Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus, the bipedal Mochlodon wore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.

The selective determination of metals in waste solutions is a very important aspect of the industry and environmental protection. Knowledge of the contents and composition of the waste can contribute to design an efficient process separation and recovery of valuable metals. The problematic issue is primarily the correct determination of metals with similar properties such as palladium and platinum. Thus this paper focuses on the development of a selective method that enables Pd(II) determination in the presence of Pt(IV) ions using the azo-dye tropaeolin OO (TR). For this purpose, the process of the metalorganic complex formation and Pd(II) ions determination were studied by using UV–Vis spectrophotometry under different conditions: solvents (water and B-R buffer), pH (2.09–6.09), temperature (20–60 °C), anions and cations concentrations. The formed metalorganic complex between Pd and tropaeolin OO allows for distinguishing Pd(II) ions from both platinum complexes, i.e. Pt(II), Pt(IV). Moreover, the proposed method can be applied to solutions containing both chloride and chlorate ions. The obtained characteristic spectrum with two maxima allows the determination of palladium even in the presence of other cations (Na, K, Mg, Zn, Co, Ni, Al) and changed concentrations of Pt(IV) ions. Furthermore, the developed spectrophotometric method for the Pd(II) ions determination using tropaeolin OO is characterized by high selectivity towards palladium ions.

With the increasing demand for liquid manipulation and microfluidic techniques, surfaces with external stimuli induced real-time tunable wetting properties are getting into the focus of materials science research. In this study, we present poly(dimethylsiloxane) (PDMS) copolymer-based composite coatings with thermally adjustable wetting and visible-light photoreactivity. To give thermal responsivity to the spray-coated or doctor blade-casted PDMS surfaces, they were grafted with poly(N-isopropylacrylamide) (PNIPAAm), applying the Activators Regenerated by Electron Transfer – Atom Transfer Radical Polymerization (ARGET-ATRP) method. As the lower critical solution temperature (LCST) of the grafted PNIPAAm chains appeared to be 34°C, the copolymer films showed thermoresponsive, and PNIPAAm surface concentration-dependent wetting characteristics. The addition of 15 wt% visible light-active plasmonic Ag-TiO2 photocatalyst nanoparticles (dprimary ~50 nm) enriched the coatings with photocatalytic activity, which was also proven to be temperature-dependent during methylene-blue (MB; c0 = 6.25 mM) photodegradation tests (blue LED-light, λ = 405 nm) at the S/L-interface. Thanks to the real-time tunable wetting and photocatalytic properties, the presented coatings may offer a novel route towards sophisticated liquid manipulation.

The influence of gemini surfactants (GSs) on the charging and aggregation features of anionic sulfate modified latex (SL) particles was investigated by light scattering techniques in aqueous dispersions. The GSs of short alkyl chains (2-4-2 and 4-4-4) resembled simple inert salts and aggregated the particles by charge screening. The adsorption of GSs of longer alkyl chains (8-4-8, 12-4-12, and 12-6-12) on SL led to charge neutralization and overcharging of the particles, giving rise to destabilization and restabilization of the dispersions, respectively. The comparison of the interfacial behavior of dimeric and the corresponding monomeric surfactants revealed that the former shows a more profound influence on the colloidal stability due to the presence of double positively charged head groups and hydrophobic tails, which is favorable to enhancing both electrostatic and hydrophobic particle-GS and GS-GS interactions at the interface. The different extent of the particle-GS interactions was responsible for the variation of the GS destabilization power, following the 2-4-2 < 4-4-4 < 8-4-8 < 12-4-12 order, while the length of the GS spacer did not affect the adsorption and aggregation processes. The valence of the background salts strongly influenced the stability of the SL-GS dispersions through altering the electrostatic interactions, which was more pronounced for multivalent counterions. These findings indicate that both electrostatic and hydrophobic effects play crucial roles in the adsorption of GSs on oppositely charged particles and in the corresponding aggregation mechanism. The major interparticle forces can be adjusted by changing the structure and concentration of the GSs and inorganic electrolytes present in the systems.

Asymmetric Michael additions of carbonyl compounds to N-substituted maleimides are among the most convenient reactions to prepare optically pure succinimide building blocks. Although a few β-amino acids were found to be highly efficient organocatalysts in the addition of α-branched aldehydes, the effect of their structure on the results of these reactions has not yet been investigated. In the present study, we disclose several unexpected and interesting structural effects of aliphatic and cycloaliphatic β-amino acids obtained in the enantioselective conjugate addition of isobutyraldehyde to N-benzylmaleimide. The dependence of the sense of the enantioselectivity on the bulkiness of the substituent on the β-carbon atom, the beneficial spatial arrangements of the functional groups in cis isomers with cyclohexane scaffold and the inversion of the enantioselectivity depending on the absence of a base additive observed with some trans isomers are unprecedented findings. The minor influence of the nitrogen substituent of the maleimide ring on both the reaction rate and the enantioselectivity was also evidenced using alicyclic β-amino acid prepared from an easily available terpene derivative.

This paper is associated with a video winner of the 2021 American Physical Society's Division of Fluid Dynamics (DFD) Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available online at the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2021.GFM.V0036.

Hybridization of steroids and other pharmacophores often modifies the bioactivity of the parent compounds, improving selectivity and side effect profile. In this study, estradiol and 3′-(un)substituted benzisoxazole moieties were combined into novel molecules by structural integration of their aromatic rings. Simple estrogen starting materials, such as estrone, estradiol and estradiol-3-methylether were used for the multistep transformations. Some of the heterocyclic derivatives were prepared from the estrane precursor by a formylation or Friedel–Crafts acylation—oximation—cyclization sequence, whereas others were obtained by a functional group interconversion strategy. The antiproliferative activities of the synthesized compounds were assessed on various human cervical, breast and prostate cancer cell lines (HeLa, MCF-7, PC3, DU-145) and non-cancerous MRC-5 fibroblast cells. Based on the primary cytotoxicity screens, the most effective cancer-selective compounds were selected, their IC50 values were determined and their apoptosis-inducing potential was evaluated by quantitative real-time PCR. Pharmacological studies revealed a strong structure–function relationship, where derivatives with a hydroxyl group on C-17 exhibited stronger anticancer activity compared to the 17-acetylated counterparts. The present study concludes that novel estradiol-benzisoxazole hybrids exert remarkable cancer cell-specific antiproliferative activity and trigger apoptosis in cancer cells.

Guided inquiry-based learning has been shown to be a promising method for science education; however, despite its advantages it is rarely used in chemistry teaching in Hungary. One of the reasons for this is the lack of tried-and-tested inquiry-based teaching materials with detailed guides that teachers can readily use in their classrooms. As part of a four-year research project, new teaching materials were designed to foster scientific reasoning and scientific process skills in chemistry education in Hungary. From these materials, in this study, a guided inquiry-based chemistry task was tested with 9th-grade students (N = 88) who had no previous experience with the method. Before the activity, the students’ mid-term grades were collected, and the Lawson Classroom Test of Scientific Reasoning (LCTSR) was administered to describe the sample. During the activity, students worked in groups (n = 21). Data were collected through content analysis of the student worksheets, classroom observations using a rubric, and student questionnaires to explore the learning paths and identify possible obstacles. Our findings support that guided inquiry learning is suitable for students who are new to the method if appropriate scaffolding is given. The data showed the phases of the inquiry cycle in which more guidance is necessary. Formulating hypotheses, recording observations, and evaluating the hypotheses based on the evidence were found to be the most critical steps in the learning process. More than half of the groups disregarded the collected evidence and accepted their original hypotheses, despite their unproven validity, suggesting that they did not understand the true nature of the scientific inquiry. Chemistry grades and the LCTSR scores could not predict reliably the students’ success in solving the inquiry task. The results of the student questionnaire showed that the students enjoyed the inquiry session. They mostly found their work successful, but they overestimated the level of their inquiry skills in some cases.

The extracellular domain of the glucagon-like peptide-1 receptor, GLP-1R, is responsible for the binding of GLP-1, and a handful of additional agonists (such as exenatide, lixisenatide, and liraglutide) used daily for treating type II diabetes mellitus. Lead discovery and optimization, however, require binding studies, which, in turn, necessitate the total synthesis of GLP-1R, comprising 108 residues. A protein domain of 10–15 kDa size could be obtained either by expression in E. coli or by ligating solid-phase peptide synthesis (SPPS)-made fragments. However, direct overexpression fails to give a properly folded protein, as GLP-1R forms an inclusion body, which fails to refold due to improper disulfide pairing. Several bacterial strains, constructs, and fusion partners were probed and it was found that only co-expression with MBP gave a 3D-fold allowing the native disulfide bond pattern formation. Some fusion partners can act as covalently linked or in situ chaperones for guiding the refolding of GLP-1R toward success. Therefore, the bottleneck to preparing GPCR extracellular domains is the correct pairing of the Cys residues. As a proof-of-concept model, nGLP1-R was made by SPPS to form the purified full-length polypeptide chain, subjected to self-guided or spontaneous Cys pairing. However, the formation of correct SS-pairs was lagging behind any protocol in use support, and the bottleneck of large-scale protein production relies on the risky step of proper refolding, which is sometimes possible only if a suitable fusion partner effectively helps and catalysis of the correct disulfide formation.

Carbon dots (CDs) are carbon-based zero-dimensional nanomaterials that can be prepared from a number of organic precursors. In this research, they are prepared using fat-free UHT cow milk through the hydrothermal method. FTIR analysis shows C=O and C-H bond presence, as well as nitrogen-based bond like C-N, C=N and –NH2 presence in CDs, while the absorption spectra show the absorption band at 280 ± 3 nm. Next, the Biuret test was performed, with the results showing no presence of unreacted proteins in CDs. It can be said that all proteins are converted in CDs. Photo luminance spectra shows the emission of CDs is 420 nm and a toxicity study of CDs was performed. The Presto Blue method was used to test the toxicity of CDs for murine hippocampal cells. CDs at a concentration of 4 mg/mL were hazardous independent of synthesis time, while the toxicity was higher for lower synthesis times of 1 and 2 h. When the concentration is reduced in 1 and 2 h synthesized CDs, the cytotoxic effect also decreases significantly, ensuring a survival rate of 60–80%. However, when the synthesis time of CDs is increased, the cytotoxic effect decreases to a lesser extent. The CDs with the highest synthesis time of 8 h do not show a cytotoxic effect above 60%. The cytotoxicity study shows that CDs may have a concentration and time–dependent cytotoxic effect, reducing the number of viable cells by 40%.

Cooperative Bi(III)/Co(II) and Bi(III)/Mn(II) heterogeneous catalysts have been developed enabling efficient oxidative annulations for preparing both cross-coupled imines and benzimidazoles under ambient conditions in an atom-economic and time-efficient manner, involving ambient air as oxidant and without the need of any other additives. This is the first synergistic Lewis acid/transition metal catalyzed annulation which is potentiated by the interfaces between the building blocks of the catalysts. To achieve our goals, a useful fabrication process has been developed to heterogenize the transition metal ions via strong interactions on well-known Sillèn-type bismuth subcarbonate (bismutite). Their reusability, activity and selectivity as well as water-tolerance have made them potential competitors to effective heterogeneous/homogeneous catalysts reported previously.

Designing new metallodrugs for anticancer therapy is a driving force in the scientific community. Aiming to contribute to this field, we hereby report the development of a Schiff base (H2L) derived from the condensation of 2-carbaldehyde-8-hydroxyquinoline with 2-hydrazinobenzothiazole and its complexation with transition metal ions. All compounds were characterised by analytical and spectroscopic techniques, which disclosed their structure: [Cu(HL)Cl], [Cu(HL)2], [Ni(HL)(acetate)], [Ni(HL)2], [Ru(HL)Cl(DMSO)], [VO(HL)2] and [Fe(HL)2Cl(H2O)]. Different binding modes were proposed, showing the ligand’s coordination versatility. The ligand proton dissociation constants were determined, and the tested compounds showed high lipophilicity and light sensitivity. The stability of all complexes in aqueous media and their ability to bind to albumin were screened. Based on an antiproliferative in vitro screening, [Ni(HL)(acetate)] and [Ru(HL)Cl(DMSO)] were selected for further studies aiming to investigate their mechanisms of action and therapeutic potential towards colon cancer. The complexes displayed IC50 < 21 μM towards murine (CT-26) and human (HCT-116) colon cancer cell lines. Importantly, both complexes exhibited superior antiproliferative properties compared to the clinically approved 5-fluorouracil. [Ni(HL)(acetate)] induced cell cycle arrest in S phase in CT-26 cells. For [Ru(HL)Cl(DMSO)] this effect was observed in both colon cancer cell lines. Additionally, both compounds significantly inhibited cell migration particularly in the human colon cancer cell line, HCT-116. Overall, the therapeutic potential of both metal complexes was demonstrated.