Given the increasing human exposure to electromagnetic radiation of various frequen-cies, mostly in the microwave range, awareness of potential health problems caused by this radiation has begun to grow. New building materials are being developed and tested to prevent or limit the penetration of microwave radiation, especially those frequencies that are used in mobile telephony. In contrast with the majority of the available literature on the investigation of concrete (cement) materials, in this paper, clay composite materials with the addition of nanoparticles of antimony(III)–tin(IV) oxide, zinc ferrite, iron(III) oxide, and two crystal modifications of titanium dioxide (rutile and anatase) were prepared in order to examine their effect on the absorption of electro-magnetic radiation. Nanomaterials are characterized by different physical and chemical methods. Specific surface area (B.E.T.), thermal properties (TGA/DSC), phase composition (PXRD), morphology (SEM), and chemical and mineralogical composition (EDX, and ED–XRF,) were determined. Thermal conductivity of clay composites was tested, and these materials showed a positive effect on the thermal conductivity (λ) of the composite: a reduction of 10–33%. The reflection and transmission coefficients of microwave radiation in the frequency range used in mobile telephony (1.5–4.0 GHz) were determined. From these data, the absolute value of radiation absorption in the materials was calculated. The results showed that the addition of the tested nanomaterials in a mass fraction of 3 to 5 wt.% significantly increases the absorption (reduces the penetration) of microwave radiation. Two nanomaterials, Sb2O3·SnO2 and TiO2 (rutile), have proven to be particularly effective: the reduction in transmission is 30–50%. The results of the test were correlated with the crystal structures of the examined nanomaterials. The inclusion of titanium dioxide and antimony-doped tin oxide into the clay led to a significant enhancement in microwave electromagnetic radiation absorption, which can be attributed to their interaction with the dielectric and conductive phases present in clay-based building materials.

The adsorption of polymers at solid-liquid interfaces is fundamental to processes such as flocculation, dispersion, and surface modification. While polymer adsorption density typically increases with molecular weight, this study demonstrates that substrate porosity can invert this trend. The adsorption behavior of polyacrylic acid (PAA) with molecularweights of 5000, 150000 and 800000 g mol-1 was investigated on two types of alumina powders: porous Linde A and non-porous AKP-50. Comprehensive characterization using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), zeta potential measurements, particle size analysis, Brunnauer-Emmett-Teller (BET) nitrogen adsorption, and mercury intrusion porosimetry confirmed the highly porous structure of Linde A and the compact, non-porous nature of Sumjitomo AKP-50. Adsorption experiments performed at pH 4, 7, and 10 revealed a complex interplay between polymer molecular weight, substrate porosity and pH. On non-porous AKP-50, adsorption density increased with molecular weight, consistent with established theory. In contrast, on porous Linde A, the lowest molecular weight PAA exhibited the highest adsorption density, attributed to greater accessibility within narrow pores. This reverse trend was most pronounced at low pH (4), where the polymer chains are coiled. At high pH, where the chains are elongated due to ionization, adsorption density became almost independent of molecularweight, as larger molecules could also enter the pore structure. A correlation between polymer molecular size and alumina pore size distribution was established, and a model of selective pore accessibility is proposed. These findings challenge conventional understanding and highlight the critical influence of substrate morphology and environmental conditions on polymer adsorption, providing valuable insights for the design of tailored polymer-based surface treatments and dispersants.

A comprehensive analysis of kidney stones is essential for the future treatment of patients. Almost all of the methods available for kidney stone analysis were used in this study. The chemical analysis included powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA-DSC). Following the chemical analysis, a detailed morphological analysis was carried out using stereoscopic microscopy, scanning electron microscopy (SEM-EDX), and micro-computed tomography (micro-CT). These investigations showed that the sixteen kidney stones analyzed in detail had a heterogeneous mineralogical structure, consisting of at least two different minerals. Kidney stones consist mainly of calcium oxalate (whewellite or weddellite) but also contain significant amounts of phosphate (mainly apatite and struvite). A thorough analysis of kidney stones can determine the cause of their formation and investigate possible treatments.

Three new complexes of copper(II) and chromone-2-carboxylic acid, a ligand from the group of hydroxypyrones, were synthesised according to the principles of green chemistry. The complexes were characterised by FT–IR and NMR spectroscopy, thermal and electrochemical analysis, and their structures are proposed. The results show the formation of mononuclear (1) and dinuclear hydroxo-bridged dinuclear copper(II) complexes (2 and 3). The results of cyclic voltammetry show that the copper in all complexes is in the +2-oxidation state. The antiproliferative activity was determined by MTT assay on 2D cell models in vitro on seven cell lines. The activity spectrum of complexes 1–3 ranged from the highest to the lowest value in the tumour cell lines tested, in the following order: Hep G2 > NCI-H358 > HT-29 > KATO III > MDA-MB 231 > Caco-2. The most effective concentration was 10−5 mol dm−3, which suppressed the growth of Hep G2 cells as follows: 69.5% (1), 64.8% (2) and 64% (3). The calculated selectivity index clearly shows that Hep G2 is the most sensitive cell line to copper complexes (SI = 1.623 (1); 1.557 (2), 1.431 (3).

The mechanisms and conditions under which urinary stones, pathological biominerals in the kidneys and bladder, are formed have not yet been fully clarified. This study aims to understand the role of the system complexity and seven different amino acids (alanine, phenylalanine, glycine, serine, cysteine, histidine, and aspartic acid) in the spontaneous precipitation of calcium oxalate. To elucidate these effects, the conditions simulating hyperoxaluria (ci(Ca2+) = 7.5 mmol dm−3 and ci(C2O42−) = 6.0 mmol dm−3) were used for the first time. In this work, systematic research on calcium oxalate precipitation was performed in three systems of different chemical complexities: (a) only calcium and oxalate ions, (b) increased ionic strength, and (c) artificial urine at two initial pHs (pHi = 5.0 and 9.0). In all the investigated systems, the dominant precipitation of calcium oxalate monohydrate (COM) was observed, except in the artificial urine system at pHi = 9.0, in which a mixture of COM and calcium oxalate dihydrate (COD) was obtained. In all the investigated systems, a significant influence of the selected amino acids on the morphology and crystal growth of COM was observed, with more pronounced changes at pHi = 9.0. Overall, polar amino acids and nonpolar phenylalanine inhibit the growth of COM, which is a more pathogenic hydrate form. The artificial urine system proved to be more relevant for the observation of effects relevant to kidney stone formation in the human body.

Heterocyclic structures are the basic building blocks of many naturally occurring organic compounds that are important for the development of essential biological processes in plants and animals, including carbohydrates and vitamins. They are also widely used as raw material sources to produce pharmaceuticals. In this study, three ligands from the groups of benzopyrones (chromone-2-carboxylic acid) and hydroxypyrones (maltol and coumalic acid), and a newly prepared complex of copper(II) nitrate with maltol as a ligand were investigated for their ability to inhibit cell proliferation. For research purposes, a series of solutions of the tested materials were prepared at different final concentrations (10–5 mol dm–3, 10–6 mol dm–3, and 10–7 mol dm–3), and then applied to a total of 7 selected cell lines, including one healthy cell line, while the others were tumour cell lines. The results of MTT cytotoxicity assay on the selected 2D cell models showed that none of the selected ligands exhibited antiproliferative activity at any concentration on any of the tested cell lines. The complex of copper(II) nitrate and maltol, in contrast to the tested ligands at the 10–5 mol dm–3 concentration, exhibited significant cytotoxicity as follows: KATO III > HT-29 > Hep G2 > NCI-H358 > MDA-MB-231 > Caco-2 > MRC-5. The healthy cell line (MRC-5) had a survival rate higher than 90.0 % at all tested concentrations, which led to the conclusion of the selectivity of the compound towards tumour cell lines.

The causes of cracks in concrete are varied, and regardless of their origin, these cracks invariably have a detrimental impact on the durability of concrete structures and escalate their maintenance costs. This paper presents a comprehensive review of current knowledge regarding the methods of self-healing in concrete, ranging from autogenic and improved autogenic self-healing to the autonomous self-healing of concrete. Particular emphasis is placed on the methods of autonomous concrete self-healing: the bacterial healing method, the crystalline hydrophilic additives healing method, and the capsule-based self-healing method. The hypothesis is that applying these self-healing methods could potentially prevent damages or cracks in concrete caused by freeze–thaw cycles, thereby extending the lifespan of concrete structures. The mechanism of action and current achievements in the field are provided for each method.

In this study, clay composites were subjected to electromagnetic transmission testing at frequencies in the region of non-ionizing radiation. Specimens were made with partial substitution of clay with different admixtures by mass. Admixtures used were Fly Ash, four different particle sizes and phases of Titanium Dioxide (TiO2), Zinc Ferrite (ZnFe2O4), Maghemite (γ-Fe2O3) and Antimony Tin Oxide (ATO). The additives were thoroughly (chemically, structurally, morphologically) characterized. The replacement percentage was 5 wt.%. Electromagnetic transmission assessment included S21 transmission coefficient measurements for samples with different additives. The lowest transmission was reported for the clay specimens with ATO and Titanium Dioxide, especially at higher frequencies. A decrease in the transmission parameter with increasing specimen thickness was also confirmed.

Most of the research dealing with the use of agro-waste as concrete aggregate implement agro-waste as a partial replacement of fine/coarse aggregate without any prior treatment of its surface. This paper investigates the influence of the complete replacement of fine/coarse aggregate with fruit pits (grape or cherry pits) on the properties of hardened concrete. The pits were used as untreated and treated with alkali solutions (2.5 % and 5 % NaOH). For untreated and treated pits, CHNS analysis was carried out while surface properties were detected by a digital microscope, Brunauer-Emmett-Teller (BET) method and computed tomography. There were no differences observed in the elemental composition between untreated and alkali treated pits. Both alkali solutions improved surface appearance of cherry pits but influenced negatively their integrity. In the case of grape pits, both concentrations had a devastating effect on their inner and outer structure. The compressive strength and the density, of the hardened concrete samples prepared with untreated and alkali treated pits, were measured according to the relevant European standards while the thermal conductivity was measured according to ISO standard. Replacing the aggregate with fruit pits decreased the density, influenced the compressive strength negatively and also reduced thermal conductivity of concrete, which results in a reduction of heat transfer and energy consumption of buildings.

Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions.

The reactions of N-benzyliminodiacetic acid (BnidaH(2)) and its para-substituted derivatives, namely: N-(p-chlorobenzyl)iminodiacetic acid (p-ClBnidaH(2)), N-(p-nitrobenzyl)iminodiacetic acid (p-NO(2)BnidaH(2)) and N-(p-methoxybenzyl)iminodiacetic acid (p-MeOBnidaH(2)) with paladium(II) chloride and 2,2'-bipyridine, were performed in water-acetonitrile solutions. Four new prepared complexes [Pd(Bnida)(bipy)]center dot 2H(2)O (1), [Pd(p-ClBnida)(bipy)]center dot 4H(2)O (2), [Pd(p-NO2 Bnida)(bipy)]center dot 2H(2)O (3) and [Pd(p-MeOBnida)(bipy)]center dot 3H(2)O (4) were identified by means of chemical analysis and mass spectrometry, and characterized by infrared spectroscopy and thermal analysis (TG/DTA). The molecular geometry and infrared spectra of these four complexes were modelled using DFT calculations at the BP86/def2-TZVP (Pd: ECP) level of theory. Extensive NMR studies have shown the presence of two isomers in solution (DMSO). The characterized palladium(II) complexes demonstrate valuable antiproliferative activity against Caco-2, SW620, NCI-H358 and MDCK I reducing cell growth from 71.7% to 79.9% (10(-4) M) (1; 4). PANC-1 display mild sensitivity and slow reduction in cell growth (less than 50%) while BJ present higher viability range and proliferative status. BJ proliferation after exposure to palladium complexes at 10(-4) M concentration ranged from 55.2% to 83.5% (1-4). In descending order, antipmliferative effect of tested palladium complexes is, as follows: 4 > 1 > 2 > 3.

Two novel discrete cadmium(II) complexes, namely [CdBr2(pia)(2)] (1) and [CdI2(pia)(2)] (2) were prepared by reactions of aqueous solutions of CdX2 (X = Br, I) salts with picolinamide (pia) in the 2:1 ligand to metal stoichiometric ratio. Both compounds were characterized by elemental analysis, IR-spectroscopy, TG/DSC analyses and electrochemical methods. The electrochemical characteristics of both ligand (pia) and prepared complexes were studied by cyclic and (cyclic) square-wave voltammetry, on a static mercury drop electrode (SMDE), in aqueous media over a wide pH range. The molecular and crystal structure of the compounds was determined by the single crystal X-ray diffraction method. X-ray structure analysis of 1 and 2 have shown that the compounds are isostructural with minor differences in the bond angles of the coordination sphere. In both compounds the Cd(II) ion is coordinated by two halide atoms and two mutually orthogonal picolinamide ligands that act as N,O-chelators in a distorted octahedral arrangement. In the crystal structure, the molecules of 1 and 2 are primarily linked via strong head-to-head amide hydrogen bond interactions forming dimers. In 1 the adjacent dimers are connected via N-H center dot center dot center dot Br hydrogen bonds and offset face to face pi center dot center dot center dot pi interactions that involve pyridine rings, while in the structure of 2, the dimers are connected via C-H center dot center dot center dot O, C-H center dot center dot center dot N and N-H center dot center dot center dot I hydrogen bonds into the final 3D structure. The intermolecular interactions in both crystal structures were further studied by Hirshfeld surface analysis. Electrochemical analysis of 2-picolinamide indicates the irreversible nature of its electro-reduction reaction on SMDE at pH 2. To provide better insight into the redox mechanism and electrokinetic properties of 2-picolinamide, the study of the effect of signal frequency on CSWV response was carried out, too. The electrochemical reduction of complex 2 involves two electron transfer reactions at -0.55 V and -0.83 V, indicating two redox active centers in the molecule, while complex 1 appears to be apparently electro-inactive in the studied potential range. (C) 2020 Elsevier Ltd. All rights reserved.

Complex perovskites have attracted extensive attention due to their fascinating physical properties and novel features owing to the coexistence of the ferro-/ferri-magnetic ground state and semiconducting behavior in the single material. Herein, the triple perovskite Sr3Co2WO9 (SCWO) has been successfully synthesized for the first time in the nanocrystalline form with an average crystallite size of 23 nm using a high yield (81%) aqueous citrate sol-gel method. At room temperature, the crystal structure of Sr3Co2WO9 is cubic, space group Fm (3) over barm, with lattice parameter a = 7.9073(6) angstrom. The formation of SCWO triple perovskite was studied in situ by X-ray diffraction and subsequently analyzed by the Rietveld analysis. The detected hysteresis loops with nonzero remanent magnetization and rather large coercive field reveal ferrimagnetic ordering with a Curie temperature of 144 K. The measured effective magnetic moment of mu(B) is close to the expected value for the rarely observed intermediate spin S = 1. It is found that the compound exhibits semiconducting properties with the optical band gaps equal to 3.52 eV (indirect) and 3.76 eV (direct), respectively, further confirmed by the determination of the AC conductivity, which in the measured temperature range (25-500 degrees C at 1 kHz) lies within the interval from 10(-5)-10(-4) Omega(-1) cm(-1). The Maxwell-Wagner model is employed to describe the frequency dependent dielectric constant. The frequency-dependent AC conductivity follows the universal Jonscher power law. Since it possesses both magnetic and semiconductor properties, this material could be a promising candidate to use in devices where its semiconducting properties would be spin-controlled.

Special-purpose river port sediment was investigated for its potential use as a road construction material. Sediment samples were extracted from three locations in three small river ports, and detailed laboratory research was conducted to determine its basic mechanical properties and characteristics that can potentially have an adverse influence in a roadside environment. The results of the research conducted indicate that there is a need for systematic monitoring of the quality and quantity of sediment in special-purpose river ports of the Danube River Basin to maintain its mobility and prevent flooding. The basic engineering characteristics (Proctor elements, Atterberg limits, California bearing ratio, and unconfined compressive strength) determined represent the good potential of the sediment samples tested herein for use in road construction. In addition, the chemical characteristics tested indicate the need for detailed analyses of the potential environmental risk before application in civil engineering structures

Characterization of nanocrystalline triple perovskites synthesized by a novel modified sol–gel route instead of bulk materials synthesized by a solid-state route.

Agricultural biomass ash is a waste material produced by incineration of residue from fields after harvesting crops. The use of agricultural biomass in industry produces large quantities of ash that represent an ecological problem. Another ecological problem is the dependency of road building on natural materials, which has been traditionally used for all pavement layers. Today, roads are built on less accessible and suitable terrains, increasing the need for improving the mechanical characteristics of locally available materials by various means of stabilisation. Within this research, three agricultural biomass fly ashes are used as lime substitutes for hydraulically stabilised soil. The purpose of this research is evaluation of potential use of agricultural biomass fly ash for the soil stabilisation of road works, i.e., for embankment and subgrade purposes. The results indicate that there is a potential of using barley, sunflower seed shells and wheat fly ash as lime substitutes in the soil stabilisation of road works. The strength characteristics of stabilised soil incorporating biomass fly ash are highly dependent on its chemical composition. Using a three-dimensional digital image correlation technique, it is concluded that the elastic properties of stabilised soil correlate to a fracture mechanism that can be efficiently defined by this modern research tool.