Ewa Talik

The results of a PM₄ (airborne particles with an aerodynamic diameter less than 4 µm) study in Katowice and in the surrounding area in homes with and without environmental tobacco smoke (ETS) are presented. It was found that the average concentration of PM₄ inside the homes with ETS was between 126 µg m⁻³ (in Jaworzno) and 208 µg m⁻³ (in Katowice)—significantly higher than in the homes without smokers (55–65 µg m⁻³). The mean of the indoor to outdoor ratios (I/O) for PM₄ varied greatly, ranging from 0.6 in the apartments without smokers in Katowice to 5.2 in the homes with smokers in Jaworzno. The highly polluted by ETS indoor air causes children aged 14–15 living in these homes to inhale from 2.5 to 6.6 mg of PM₄ more per day than their peers living in non-ETS homes. X-ray photoelectron spectroscopy (XPS) was used to determine the surface chemical composition of the studied indoor airborne particles. Carbon, including elemental carbon, and oxygen-containing species dominated the particulate surface, with traces of Si, N, S, Na, Al, Zn, and K present. The surface layer of PM₄ from the homes with ETS contains significantly more carbon and less oxygen than the airborne particles collected in the homes without smokers, which can be explained by the high emission of carbon during tobacco smoking.

This paper refers to the structural and magnetic properties of [(Fe₈₀Nb₆B₁₄)_0.88Dy_0.12]_1−xZr_x (x = 0; 0.01; 0.02; 0.05; 0.1; 0.2; 0.3; 0.5) alloys obtained by the vacuum mold suction casting method. The analysis of the phase contribution indicated a change in the compositions of the alloys. For x < 0.05, occurrence of the dominant Dy₂Fe₁₄B phase was observed, while a further increase in the Zr content led to the increasing contribution of the Fe–Zr compounds and, simultaneously, separation of crystalline Dy. The dilution of (Fe₈₀Nb₆B₁₄)_0.88Dy_0.12 in Zr strongly influenced the magnetization processes of the examined alloys. Generally, with the increasing x parameter, we observed a decrease in coercivity; however, the unexpected increase in magnetic saturation and remanence for x = 0.2 and x = 0.3 was shown and discussed.

Crystal structure, microstructural chemical analysis, magnetic properties and magnetocaloric effect for ‘as cast’ and annealed Gd_4−xTb_xCo₃ (x = 0–4) were investigated. Only Gd₄Co₃ was homogeneous and crystallised in the hexagonal Ho₄Co₃-type of crystal structure. Samples substituted with terbium proved to be a mixture of (Gd,Tb)₁₂Co₇ and (Gd,Tb)Co₂ phases. With the increase of terbium content the entropy change increased and for the samples with x = 3, 4 reached the highest values. Even ‘as-cast’ samples exhibit pronounced values of the magnetocaloric parameters.

Vascular plants are able to conduct biomineralization processes and collect synthesized compounds in their internal tissues or to deposit them on their epidermal surfaces. This mechanism protects the plant from fluctuations of nutrient levels caused by different levels of supply and demand for them. The biominerals reflect both the metabolic characteristics of a vascular plant species and the environmental conditions of the plant habitat. The SEM/EDX method was used to examine the surface and cross-sections of the Calamagrostis epigejos and Phragmites australis leaves from post-industrial habitats (coal and zinc spoil heaps). The results from this study have showed the presence of mineral objects on the surfaces of leaves of both grass species. The calcium oxalate crystals, amorphous calcium carbonate spheres, and different silica forms were also found in the inner tissues. The high variety of mineral forms in the individual plants of both species was shown. The waxes observed on the leaves of the studied plants might be the initializing factor for the crystalline forms and structures that are present. For the first time, wide range of crystal forms is presented for C. epigejos. The leaf samples of P. australis from the post-industrial areas showed an increased amount of mineral forms with the presence of sulfur.

Bioactivity investigations of titania nanotube (TNT) coatings enriched with silver nanograins (TNT/Ag) have been carried out. TNT/Ag nanocomposite materials were produced by combining the electrochemical anodization and chemical vapor deposition methods. Fabricated coatings were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The release effect of silver ions from TNT/Ag composites immersed in bodily fluids, has been studied using inductively coupled plasma mass spectrometry (ICP-MS). The metabolic activity assay (MTT) was applied to determine the L929 murine fibroblasts adhesion and proliferation on the surface of TNT/Ag coatings. Moreover, the results of immunoassays (using peripheral blood mononuclear cells—PBMCs isolated from rats) allowed the estimation of the immunological activity of TNT/Ag surface materials. Antibacterial activity of TNT/Ag coatings with different morphological and structural features was estimated against two Staphylococcus aureus strains (ATCC 29213 and H9). The TNT/Ag nanocomposite layers produced revealed a good biocompatibility promoting the fibroblast adhesion and proliferation. A desirable anti-biofilm activity against the S. aureus reference strain was mainly noticed for these TiO₂ nanotube coatings, which contain dispersed Ag nanograins deposited on their surface.

Titania nanotube (TNT) coatings were produced using low-potential anodic oxidation of Ti6Al4V substrates in the potential range 3–20 V. They were analysed by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The wettability was estimated by measuring the contact angle when applying water droplets. The bioactivity of the TNT coatings was established on the basis of the biointegration assay (L929 murine fibroblasts adhesion and proliferation) and antibacterial tests against Staphylococcus aureus (ATCC 29213). The photocatalytic efficiency of the TNT films was studied by the degradation of methylene blue under UV irradiation. Among the studied coatings, the TiO₂ nanotubes obtained with the use of 5 V potential (TNT5) were found to be the most appropriate for medical applications. The TNT5 sample possessed antibiofilm properties without enriching it by additional antimicrobial agent. Furthermore, it was characterized by optimal biocompatibility, performing better than pure Ti6Al4V alloy. Moreover, the same sample was the most photocatalytically active and exhibited the potential for the sterilization of implants with the use of UV light and for other environmental applications.

Plasma enhanced atomic layer deposition (PEALD) of silver nanoparticles on the surface of 1-D titania coatings, such as nanotubes (TNT) and nanoneedles (TNN), has been carried out. The formation of TNT and TNN layers enriched with dispersed silver particles of strictly defined sizes and the estimation of their bioactivity was the aim of our investigations. The structure and the morphology of produced materials were determined using X-ray photoelectron spectroscopy (XPS) and scanning electron miscroscopy (SEM). Their bioactivity and potential usefulness in the modification of implants surface have been estimated on the basis of the fibroblasts adhesion and proliferation assays, and on the basis of the determination of their antibacterial activity. The cumulative silver release profiles have been checked with the use of inductively coupled plasma-mass spectrometry (ICPMS), in order to exclude potential cytotoxicity of silver decorated systems. Among the studied nanocomposite samples, TNT coatings, prepared at 3, 10, 12 V and enriched with silver nanoparticles produced during 25 cycles of PEALD, revealed suitable biointegration properties and may actively counteract the formation of bacterial biofilm.