20 research outputs found

    Evaluation of phytotoxicity and cytotoxicity of industrial catalyst components (Fe, Cu, Ni, Rh and Pd): A case of lethal toxicity of a rhodium salt in terrestrial plants

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    Until recently, chemical derivatives of platinum group metals have not been in a systematic direct contact with living organisms. The situation has changed dramatically due to anthropogenic activity, which has led to significant redistribution of these metals in the biosphere. Millions of modern cars are equipped with automotive catalytic converters, which contain rhodium, palladium and platinum as active elements. Everyday usage of catalytic technologies promotes the propagation of catalyst components in the environment. Nevertheless, we still have not accumulated profound information on possible ecotoxic effects of these metal pollutants. In this study, we report a case of an extraordinarily rapid development of lethal toxicity of a rhodium (III) salt in the terrestrial plants Pisum sativum, Lupinus angustifolius and Cucumis sativus. The growth stage, at which the exposure occurred, had a crucial impact on the toxicity manifestation: at earlier stages, RhCl3 killed the plants within 24 h. In contrast, the salt was relatively low-toxic in human fibroblasts. We also address phytotoxicity of other common metal pollutants, such as palladium, iron, nickel and copper, together with their cytotoxicity. None of the tested compounds exhibited phytotoxic effects comparable with that of RhCl3. These results evidence the crucial deficiency in our knowledge on environmental dangers of newly widespread metal pollutants

    Structural phase states in nickel-titanium surface layers doped with silicon by plasma immersion ion implantation

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    The paper reports on a study of NiTi-based alloys used for manufacturing self-expanding intravascular stents to elucidate how the technological modes of plasma immersion ion implantation with silicon influence the chemical an

    Metal hydride hydrogen storage and compression systems for energy storage technologies

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    Along with a brief overview of literature data on energy storage technologies utilising hydrogen and metal hydrides, this article presents results of the related R&D activities carried out by the authors. The focus is put on proper selection of metal hydride materials on the basis of AB5- and AB2-type intermetallic compounds for hydrogen storage and compression applications, based on the analysis of PCT properties of the materials in systems with H2 gas. The article also presents features of integrated energy storage systems utilising metal hydride hydrogen storage and compression, as well as their metal hydride based components developed at IPCP and HySA Systems

    Compressive Strength Characteristics of Long Tubular Bones after Hyperthermal Ablation

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    Thermoablation is used in the treatment of tumorous bones. However, little is known about the influence such thermal treatment has on the mechanical properties of bone tissue. The purpose of this work was to study the influence of thermal treatment in a range of 60–100 °C (in increments of 10 °C) on the structural properties of pig femurs using an original approach that involved a periosteal arrangement of heating elements providing gradual dry heating of the bone from its periphery to its center. Heating of freshly extracted bone tissue segments was performed ex vivo using surface heaters of a Phoenix-2 local hyperthermia hardware system. Mechanical testing followed the single-axis compression scheme (traverse velocity of 1 mm/min). In the 60–90 °C range of heating, no attributes of reduced structural characteristics were found in the samples subjected to thermoablation in comparison to the control samples taken from symmetric areas of adjacent cylinders of healthy bones and not subjected to heat treatment. The following statistically significant changes were found as a result of compressing the samples to 100 °C after the heat treatment: reduced modulus of elasticity and increased elastic strain (strain-to-failure), mainly due to increases in plastic deformation. This finding may serve as evidence of a critical ex vivo change in the biomechanical behavior of bone tissues at such temperatures. Thus, ex vivo treatment of bone tissue in the thermal range of 60–90 °C may be used in studies of thermoablation efficiency against tumor involvement of bones

    Compressive Strength Characteristics of Long Tubular Bones after Hyperthermal Ablation

    No full text
    Thermoablation is used in the treatment of tumorous bones. However, little is known about the influence such thermal treatment has on the mechanical properties of bone tissue. The purpose of this work was to study the influence of thermal treatment in a range of 60–100 °C (in increments of 10 °C) on the structural properties of pig femurs using an original approach that involved a periosteal arrangement of heating elements providing gradual dry heating of the bone from its periphery to its center. Heating of freshly extracted bone tissue segments was performed ex vivo using surface heaters of a Phoenix-2 local hyperthermia hardware system. Mechanical testing followed the single-axis compression scheme (traverse velocity of 1 mm/min). In the 60–90 °C range of heating, no attributes of reduced structural characteristics were found in the samples subjected to thermoablation in comparison to the control samples taken from symmetric areas of adjacent cylinders of healthy bones and not subjected to heat treatment. The following statistically significant changes were found as a result of compressing the samples to 100 °C after the heat treatment: reduced modulus of elasticity and increased elastic strain (strain-to-failure), mainly due to increases in plastic deformation. This finding may serve as evidence of a critical ex vivo change in the biomechanical behavior of bone tissues at such temperatures. Thus, ex vivo treatment of bone tissue in the thermal range of 60–90 °C may be used in studies of thermoablation efficiency against tumor involvement of bones

    Mechanical and Histological Characteristics of Human Tubular Bones after Hyperthermal Treatment

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    This research focused on studying regularities in changes in strength characteristics and histological patterns of healthy tubular bone tissue depending on the temperature setting of hyperthermal treatment. Experimentation has established that heating the experimental bone sample in a temperature range of 60 to 70 °C does not cause any decline in strength characteristics compared to the control samples not subject to heat treatment. In compression tests (along the length of the bone), after heating the bone samples ex vivo to 80 °C, the strength characteristics were found to increase as the samples sustained a higher maximum stress. In bending tests, in contrast, the strength characteristics were reliably found to decrease in bone samples at 80 °C and 90 °C for the maximum stress indicator and 90 °C for the modulus of elasticity. Data obtained through histological examination further demonstrated statistically significant differences between the two temperature ranges of 60–70 °C and 80–90 °C, where semi-quantitative assessment revealed statistically significant differences in the markers of bone tissue destruction caused by hyperthermal treatment. Moderate (at 60–70 °C) and pronounced (at 80–90 °C) dystrophic and necrotic changes were observed both in the cells and the intercellular matrix of the tibia. From a practical point of view, the temperature range of 60–70 °C can be considered operational for thermal ablation since, at these temperatures, no statistically significant decline was observed for the strength characteristics in either the cross-section or length-section

    Ionic Liquids As Tunable Toxicity Storage Media for Sustainable Chemical Waste Management

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    Storage and handling of toxic wastes is a top-priority challenge for sustainable development and public health. In recent years, the risk of irreversible environmental pollution has been increasing gradually, necessitating the development of new concepts in this highly demanding area. Here, we report a flexible approach to address the problem using tunable ionic liquids as a carrier and storage medium for chemicals. Encapsulation in microscale tunable media surrounded by an inert ionic liquid facilitates the efficient capture of chemicals. The adaptive character of the designed microscale compartments opens new possibilities for the waste management of chemicals of a diverse nature. Real-time field-emission scanning electron microscopy was used to visualize the formation of microscale compartments upon the sequestration of chemicals in ionic liquids. Ionic liquids captured the chemicals better than traditional organic solvents or water; moreover, the chemicals subsequently could be effectively extracted for destruction or utilization. Our work presents a new model for the sustainable management of chemical wastes; the concept was evaluated for a number of multiton chemicals currently affecting our environment

    Severe Plastic Deformation of Mg–Zn–Zr–Ce Alloys: Advancing Corrosion Resistance and Mechanical Strength for Medical Applications

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    Magnesium-based alloys hold potential for medical applications, but face challenges like rapid bioresorption and limited mechanical strength during early bone healing. In our study, we present a novel Mg–Zn–Zr–Ce alloy with low cerium content (up to 0.1 wt.% Ce) processed using two severe plastic deformation (SPD) techniques. Through an innovative combination of multiaxial forging and multipass rolling, we have achieved a fine-grained structure with an average grain size of the primary α-Mg phase of 1.0 μm. This refined microstructure exhibits improved mechanical properties, including a substantial increase in yield strength (σYS) from 130 to 240 MPa, while preserving ductility. The alloy’s composition includes α-Mg grains, cerium and zinc hydrides, and intermetallic phases with cerium and zinc elements. Tensile testing of the fine-grained alloy demonstrates an enhancement in yield strength (σYS) to 250 MPa, marking a 2.8-fold improvement over the conventional state (σYS = 90 MPa), with a modest 2-fold reduction in ductility. Crucially, electrochemical tests conducted in physiological solutions highlight substantial advancements in corrosion resistance. The corrosion current was reduced from 14 to 2 μA/cm2, while polarization resistance decreased from 3.1 to 8.1 kΩ∙cm2, underlining the alloy’s enhanced resistance to biodegradation. Our results show that the novel Mg–Zn–Zr–Ce alloy, after combined SPD, demonstrates mitigated bioresorption and enhanced mechanical properties. Our findings highlight the fact that the introduction of this innovative alloy and the application of SPD represent significant steps towards addressing the limitations of magnesium-based alloys for medical implants, offering potential improvements in safety and effectiveness
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