Antibacterial properties of PMMA functionalized with CuFe2O4/Cu2O/CuO nanoparticles

We have prepared a composite thin coating by incorporation of CuFe2O4/Cu2O/CuO nanoparticles in polymethyl methacrylate (PMMA) matrix by using the solution casting method. The electrical explosion of two twisted wires (EETW) was used to obtain multicomponent CuFe2O4/Cu2O/CuO nanoparticles with an average particle size of 20–70 nm. The microscopic studies showed that the nanoparticles in the composite coatings are evenly distributed. However, nanoparticles are strongly agglomerated as the powder concentration in the coating increases to 5 wt.% and 10 wt.%, as the size of particle agglomerates increases to 50 and 100 µm, respectively. Therefore, nanoparticles were pre-treated with ultrasound when introduced into the PMMA matrix. The thermal stability of the composite coating does not change with the introduction of CuFe2O4/Cu2O/CuO nanoparticles in the amount of 5 wt.%. The inclusion of nanoparticles in the PMMA matrix significantly enhances its antibacterial activity. The addition of 5 wt.% nanoparticles inhibited the growth of E. coli by 100% and the growth of MRSA by 99.94% compared to pure PMMA already after 3 h of exposure of bacteria on the surface of the composites. This research provides an easy-to-manufacture and cost-efficient method for producing a uFe2O4/Cu2O/CuO/PMMA composite coating with a broad application as an antibacterial material

Phenological shifts of abiotic events, producers and consumers across a continent

Ongoing climate change can shift organism phenology in ways that vary depending on species, habitats and climate factors studied. To probe for large-scale patterns in associated phenological change, we use 70,709 observations from six decades of systematic monitoring across the former Union of Soviet Socialist Republics. Among 110 phenological events related to plants, birds, insects, amphibians and fungi, we find a mosaic of change, defying simple predictions of earlier springs, later autumns and stronger changes at higher latitudes and elevations. Site mean temperature emerged as a strong predictor of local phenology, but the magnitude and direction of change varied with trophic level and the relative timing of an event. Beyond temperature-associated variation, we uncover high variation among both sites and years, with some sites being characterized by disproportionately long seasons and others by short ones. Our findings emphasize concerns regarding ecosystem integrity and highlight the difficulty of predicting climate change outcomes. The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.Peer reviewe

Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

Media Flows Analysis for Sustainable Development of Urban Environment

An objective analysis of multidimensional media flows in the implementation of the concept of sustainable development of the urban environment is based on methods of statistical data processing, the sample of which is subject to certain constraints to improve the reliability statistical conclusions. In particular, the presence of serial correlation in the series of a random variable reduces the reliability of statistical estimates. This paper proposes a method for assessing the intensity of information flows generated by a separate media source against the background of two different dominant informational agendas: before and after the outbreak of coronavirus infection. The technique makes it possible to assess the probability of the media generating messages of a given discourse taking into account the autocorrelation of the series. The developed and implemented algorithm for assessing the likelihood of information messages on a given topic can be used in the future to study the stability of information intrusions into the target media space, as well as to simulate the consequences of the implementation of measures for the digital transformation of the urban environment within the concept of its sustainable development

Biofouling as one of the Factors of Sustainable Development of Shipbuilding

Sea transportation is one of the cheapest and most widespread types of cargo transportation, and the process of fouling of the vessel’s hull has an extremely negative impact on its maneuverability and running characteristics. This leads to excessive consumption of fuel, an increase in the cost of delivery of goods and environmental risks. Namely, when additional fuel is burned, the emission of the greenhouse gas CO2 increases. Considering the accompanying environmental risks in the long-term planning of the shipbuilding industry will ensure the sustainability of its development. In the study we suggest a simple way to assess quantitatively the development strategy of shipbuilding from the point of view of the accompanying economic and environmental consequences by constructing a matrix model for the industry development. The matrix model was applied to the Strategy for Development of the Shipbuilding Industry in Russia until 2035. In the future, on the basis of the offered model, it is possible to develop optimal environmentally neutral scenarios for shipbuilding development

The Black Sea Zooplankton Mortality, Decomposition, and Sedimentation Measurements Using Vital Dye and Short-Term Sediment Traps

The principal objectives of this research are to measure the non-consumptive mortality rate of marine copepod zooplankton and the sedimentation rate of copepod carcasses, using short-term sediment traps, and to reveal a correlation between the rates of the two competitive processes—sedimentation and degradation of the carcasses under turbulent mixing conditions. The traps were moored in Sevastopol Bay and adjacent coastal waters (the Black Sea) during summer and autumn seasons. A simulation model was developed to describe a wide range of processes in the trap and the water column above it and to interpret the results obtained with the sediment traps. Significant changes in the abundance of copepod carcasses (from 280 to 12,443 ind. m−3) and their fraction in the total zooplankton abundance (53 to 81%) were observed in the waters over short time periods, indicating a high variability of zooplankton mortality, sedimentation, and decomposition rates. Despite the high concentrations of copepod carcasses in the water column, the rates of their accumulation in the traps proved to be extremely low, which could be due to intense turbulent mixing of the waters. The carcass sedimentation rate and the flow of swimmers (motile copepods) into the traps were significantly higher in waters subjected to weaker turbulent mixing. The obtained estimates of the sedimentation rate of copepod carcasses (0.012 to 0.39 d−1) were comparable in value with the rate of their microbial decomposition (0.13 and 0.05 d−1 in the bay and adjacent waters, respectively). This confirmed the hypothesis on microbial decomposition as one of the key controls of the fraction of live zooplankton organisms in zooplankton

Urban sustainable development using qualimetry procedures of digital transformation

The use of information technologies to improve the efficiency of organizing the functioning of urban processes and the provision of innovative services forms the basis of the concept of smart sustainable city. Society mistakenly identify the digital transformation of the urban environment with the unsystematic, redundant introduction of technical innovations into the citizens’ life. This is because the changes made to the habitual processes of citizens' life often do not pass the mandatory check for their balance in terms of compliance with principles of sustainable development. The article proposes a new conceptual approach for assessing the effectiveness of the implemented solutions related to the implementation of the paradigm that ensures the transition from technology-oriented to human-oriented concept of “Sustainable Smart Cities”. The main idea is to consider the transformation of the urban environment through the prism of changes in the functional state of its objects

Media Flows Analysis for Sustainable Development of Urban Environment

An objective analysis of multidimensional media flows in the implementation of the concept of sustainable development of the urban environment is based on methods of statistical data processing, the sample of which is subject to certain constraints to improve the reliability statistical conclusions. In particular, the presence of serial correlation in the series of a random variable reduces the reliability of statistical estimates. This paper proposes a method for assessing the intensity of information flows generated by a separate media source against the background of two different dominant informational agendas: before and after the outbreak of coronavirus infection. The technique makes it possible to assess the probability of the media generating messages of a given discourse taking into account the autocorrelation of the series. The developed and implemented algorithm for assessing the likelihood of information messages on a given topic can be used in the future to study the stability of information “intrusions” into the target media space, as well as to simulate the consequences of the implementation of measures for the digital transformation of the urban environment within the concept of its sustainable development

Antibacterial Properties of PMMA Functionalized with CuFe2O4/Cu2O/CuO Nanoparticles

We have prepared a composite thin coating by incorporation of CuFe2O4/Cu2O/CuO nanoparticles in polymethyl methacrylate (PMMA) matrix by using the solution casting method. The electrical explosion of two twisted wires (EETW) was used to obtain multicomponent CuFe2O4/Cu2O/CuO nanoparticles with an average particle size of 20–70 nm. The microscopic studies showed that the nanoparticles in the composite coatings are evenly distributed. However, nanoparticles are strongly agglomerated as the powder concentration in the coating increases to 5 wt.% and 10 wt.%, as the size of particle agglomerates increases to 50 and 100 μm, respectively. Therefore, nanoparticles were pre-treated with ultrasound when introduced into the PMMA matrix. The thermal stability of the composite coating does not change with the introduction of CuFe2O4/Cu2O/CuO nanoparticles in the amount of 5 wt.%. The inclusion of nanoparticles in the PMMA matrix significantly enhances its antibacterial activity. The addition of 5 wt.% nanoparticles inhibited the growth of E. coli by 100% and the growth of MRSA by 99.94% compared to pure PMMA already after 3 h of exposure of bacteria on the surface of the composites. This research provides an easy-to-manufacture and cost-efficient method for producing a CuFe2O4/Cu2O/CuO/PMMA composite coating with a broad application as an antibacterial material