The article provides an overview of regional economic indicators of the Slovak-Ukrainian borderlands in the period 2010 – 2020, following the Regional economic performance index ranking. It focuses ...on economic performance, socio-economic characteristics, mutual trade, foreign direct investment, and labour migration in the analysed regions. The impacts of the gradual DCFTA implementation are reflected and discussed.
We draw on a substantial body of theoretical and empirical research on Internet of Things sensors and digital urban governance in data-driven smart sustainable cities, and to explore this, we ...inspected, used, and replicated survey data from BDO, Bentley, ESI ThoughtLab, ICMA, KPMG, RICS, SSC, and World Economic Forum, performing analyses and making estimates regarding how Internet of Things-enabled smart cities harness interconnected sensor networks and machine learning-based analytics. Data-driven planning technologies and machine learning-based analytics articulate networked and integrated sustainable urban technologies. Smart and environmentally sustainable cities leverage Internet of Things sensing infrastructures. Integrating Internet of Things sensing infrastructures furthers the ad- vancement of groundbreaking services and sensor-based big data applications across Internet of Things-enabled smart cities. Networked and integrated sustainable urban technologies can be pivotal in the development of sustainable urban governance net- works. Deep learning can assist Internet of Things sensing infrastructures in smart sustainable city governance and management. Descriptive statistics of compiled data from the completed surveys were calculated when appropriate.
A completely solid-state mechanochemical synthesis of silver nanoparticles overcoming the problem with water insolubility of lichen metabolites hampering their use for the classical green synthesis ...in water is shown herein. Four lichen species (Xanthoria elegans, Cetraria islandica, Usnea antarctica, and Leptogium puberulum) and AgNO3 were used as reducing agents and Ag(0) precursor, respectively. The reaction progress was rapid in the first two cases, whereas in the case of U. antarctica and L. puberulum, a significant amount of AgNO3 could still be detected after 6 h of milling. The products with a higher content of Ag(0) were shown to undergo a backward transformation documented by increasing content of AgNO3 with storage time; however, the repeated formation of Ag(0) could be observed upon remilling. Transmission electron microscopy analysis has shown bimodal nanocrystallite size distribution in all cases. However, the finer fraction was more abundant in the case of silver nanoparticles prepared using lichens with stronger reducing ability (X. elegans and C. islandica). All the products are excellent antibacterial agents. Whereas the as-received products exhibited higher activity against E. coli, the remilled samples were more active against S. aureus.
This paper is focused on the preparation of novel hybrid polymer composite materials for 3D filaments. As the reinforcing filler, expanded graphite, carbon fibers, and combinations thereof were used ...in various ratios up to 10%. The mechanical and thermal properties of virgin and recycled polyethylene phthalate glycol-modified (PETG) composite materials were determined. Almost all prepared composite materials were suitable for 3D printing and they have enhanced mechanical properties compared to the neat PETG matrices. Addition of the fillers to both polymer matrices has an only slight effect on the thermal stability, but the addition of carbon fibers significantly reduced the thermal expansion coefficient. The composites from cheaper recycled PETG have comparable properties to virgin PETG composites, which is of economic and ecological importance. New and cheaper materials can help expand 3D printing to manufacturing plants and the use of 3D printers for special applications.
•To maintain enough antibacterial agent concentration in infected area.•To investigate antibacterial activity of quantum DOTs.•To eradicate Gram positive (Staphylococcus aureus, Listeria ...monocytogenes) and Gram negative (Escherichia coli, Klebsiella pneumoniae) bacteria.
Inhabitation of various types of bacteria on different surfaces causes vital health problems worldwide. In this work, a wound dressing defeating bacterial infection had been fabricated. The antibacterial effect of polycaprolactone and hydrophobic carbon quantum dots (hCQDs) based nanocomposite has been presented. The nanocomposite was fabricated both via solvent casting and electrospinning method. Nanocomposites with and without hCQDs had been investigated. A detailed study on their morphology and surface properties were performed by scanning electron microscopy, atomic force microscopy and Raman spectroscopy. Prepared nanocomposites had been evaluated by the contact angle, UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy, and antibacterial activity. It was found that nanocomposites were able to produce singlet oxygen upon blue light irradiation at 470 nm, and they were effective in the eradication of Gram positive (Staphylococcus aureus, Listeria monocytogenes) and Gram negative (Escherichia coli, Klebsiella pneumoniae) bacteria.
This study shows mechanochemical synthesis as an alternative method to the traditional green synthesis of silver nanoparticles in a comparative manner by comparing the products obtained using both ...methodologies and different characterization methods. As a silver precursor, the most commonly used silver nitrate was applied and the easily accessible lavender (
L.) plant was used as a reducing agent. Both syntheses were performed using 7 different lavender:AgNO
mass ratios. The synthesis time was limited to 8 and 15 min in the case of green and mechanochemical synthesis, respectively, although a significant amount of unreacted silver nitrate was detected in both crude reaction mixtures at low lavender:AgNO
ratios. This finding is of particular interest mainly for green synthesis, as the potential presence of silver nitrate in the produced nanosuspension is often overlooked. Unreacted AgNO
has been removed from the mechanochemically synthesized samples by washing. The nanocrystalline character of the products has been confirmed by both X-ray diffraction (Rietveld refinement) and transmission electron microscopy. The latter has shown bimodal size distribution with larger particles in tens of nanometers and the smaller ones below 10 nm in size. In the case of green synthesis, the used lavender:AgNO
ratio was found to have a decisive role on the crystallite size. Silver chloride has been detected as a side-product, mainly at high lavender:AgNO
ratios. Both products have shown a strong antibacterial activity, being higher in the case of green synthesis, but this can be ascribed to the presence of unreacted AgNO
. Thus, one-step mechanochemical synthesis (without the need to prepare extract and performing the synthesis as separate steps) can be applied as a sustainable alternative to the traditional green synthesis of Ag nanoparticles using plants.
Abstract 3D printing provides a lot of varieties for the manufacturing of personalized biomedical devices. Incorporation of the nanoparticles with potential antibacterial activity to the printed ...materials is another added value. One example of such nanoparticles are hydrophobic carbon quantum dots (hCQDs), which are zero-dimensional redox-active materials with high chemical stability and low production costs. They produce singlet oxygen only when activated by a specific wavelength of visible blue light which allows for controlled antibacterial action and minimizes the chances of bacterial resistance emergence. We prepared and characterized polymer composites based on thermoplastic elastomers (TPE) doped with hCQDs (TPE/hCQDs). The composites were 3D printed using fused deposition modeling method. In the first set of samples, a filament of pure TPE was immersed in a solution of hCQDs (0.5 mg/mL), then 3D printed, and compared with unmodified TPE filament. The mechanical properties, swelling behavior, hardness, and thermal stability of TPE/hCQDs were compared with the pure TPE printed samples. The production of singlet oxygen was confirmed by the electron paramagnetic resonance method. The antibacterial activity of the samples was tested according to ISO 22196 against Staphylococcus aureus and Escherichia coli after one hour of exposure to blue light, which completely inhibited bacterial growth. Besides, the cytotoxicity of samples was evaluated by MTT assay, and no significant effect of the materials on cell viability was observed. 3D printed materials with antibacterial activity represent a perspective for the future, especially in the field of personalized medicine, as well as in products for other industries.
The effect of hollow glass beads on poly(ε-caprolactone) (PCL) oxidative degradation has been evaluated by the non-isothermal chemiluminescence (CL) method and thermogravimetry analysis (TGA). The ...main goal of the research and this publication was to reduce the production costs associated with the materials for 3D printing, which would also have a low mass, excellent biocompatibility and suitable thermal properties. Experiments have clearly shown the dual effect of a filler and its extent in terms of poly(ε-caprolactone). The chosen methods demonstrate the superposition of both the pro-degradation and stabilization effects of hollow glass beads on the polymer. The former was evident above the load of 10 wt.% of filler. The non-isothermal TGA records were analyzed as being composed of three temperature-dependent processes of the first-order kinetics. A massive compensation effect between the so-called activation energy and the logarithm of pre-exponential factors for heating rates of 2.5, 5 and 10 °C/min has been shown to be typical for similar non-isothermal thermogravimetry evaluation.
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