Publications

Abstract Micro- and nanoplastics (MNPs) are an important atmospheric aerosol constituent. However, there still needs to be a standard procedure for their sampling and size fractionation, which is an obstacle to the aggregation and critical analysis of results obtained by different research groups. This review focuses on the sampling and fractionation methodologies used for MNPs. Moreover, a streamlined, simplified methodology for sampling and fractionation is proposed.

Abstract <jats:p>Green carbon-based materials (GCM), i.e. carbon materials produced using renewable biomass or recycled wastes, ought to be used in order to processes become sustainable and carbon neutral. Carbon nanomaterials, like for example carbon dots and nanobichar families, and carbon materials, like for example activated carbon and biochar substances, are sustainable materials with great potential to be used in different technology applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) critically reviewed: agriculture; water treatment; energy management; and, carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and play an important role in the sustainability of the processes, contributing to the mitigation of the climate change, namely by reducing emission and increase sequestration of CO2eq..</jats:p>

Abstract Green carbon-based materials (GCM), i.e., carbon materials produced using renewable biomass or recycled waste, ought to be used to make processes sustainable and carbon-neutral. Carbon nanomaterials, like carbon dots and the nanobichar families, and carbon materials, like activated carbon and biochar substances, are sustainable materials with great potential to be used in different technological applications. In this review, the following four applications were selected, and the works published in the last two years (since 2022) were critically reviewed: agriculture, water treatment, energy management, and carbon dioxide reduction and sequestration. GCM improved the performance of the technological applications under revision and played an important role in the sustainability of the processes, contributing to the mitigation of climate change, by reducing emissions and increasing the sequestration of CO2eq.

Abstract <jats:p>Mozambique is one of the poorest countries of the world. However, it has natural resources and if they are managed under sustainable development principles, Mozambique can overcome the current problems. In the present socio-economic status, soil is one of its most important resources and must be protected from pollution and from degradation. This review focuses on the identification and discussion of the main soil quality stressors, namely: soil fertility; deforestation and its sources: agriculture, timber harvesting, charcoal production and uncontrolled fires; mining activities, manly gold artisanal explorations and industrial open-pit coal mining. The sustainable use of the natural resources is mandatory to allow future generations to continue profiting for this nature-based wealth.</jats:p>

Abstract Mozambique is one of the poorest countries in the world. However, it has natural resources, and if they are managed under sustainable development principles, it can overcome its current problems. In the present socio-economic status, soil is one of its most important resources and must be protected from pollution and degradation. This review identifies and discusses the main soil quality stressors, namely soil fertility; deforestation and its sources: agriculture, timber harvesting, charcoal production, and uncontrolled fires; mining activities, manly gold artisanal explorations, and industrial open-pit coal mining; and solid wastes management. The sustainable use of natural resources is mandatory for future generations to continue to profit from this nature-based wealth.

Abstract Bioluminescence (BL) and chemiluminescence (CL) are remarkable processes in which light is emitted due to (bio)chemical reactions. These reactions have attracted significant attention for various applications, such as biosensing, bioimaging, and biomedicine. Some of the most relevant and well-studied BL/CL systems are that of marine imidazopyrazine-based compounds, among which Coelenterazine is a prime example. Understanding the mechanisms behind efficient chemiexcitation is essential for the optimization and development of practical applications for these systems. Here, the CL of a fluorinated Coelenterazine analog was studied using experimental and theoretical approaches to obtain insight into these processes. Experimental analysis revealed that CL is more efficient under basic conditions than under acidic ones, which could be attributed to the higher relative chemiexcitation efficiency of an anionic dioxetanone intermediate over a corresponding neutral species. However, theoretical calculations indicated that the reactions of both species are similarly associated with both electron and charge transfer processes, which are typically used to explain efficiency chemiexcitation. So, neither process appears to be able to explain the relative chemiexcitation efficiencies observed. In conclusion, this study provides further insight into the mechanisms behind the chemiexcitation of imidazopyrazinone-based systems.

Abstract In this investigation, Co-, Ni- and Cu-doped ZnO nanoparticles were prepared using precipitation methods. The characterization of the as-prepared nanomaterials was carried out using XRD, FT-IR, DRS, XPS and SEM. The XRD analysis showed that the insertion of foreign metal ions into the matrix of ZnO caused a slight shift of the positions of (100), (002) and (101) diffraction peaks of ZnO towards the lower 2 theta, by comparison with pure ZnO. The DRS results showed that Co-doped ZnO nanoparticles absorb wavelengths higher than 400 nm. The estimated band gaps (eV) were 2.48, 3.17 and 3.14 for 10 %Co-ZnO, 10 %Ni-ZnO and 10 %Cu-ZnO respectively. The XPS results showed the existence of two valence states for Co and Ni (Co2+/Co3+ and Ni2+/Ni3+) while Cu exists in the form of Cu2+. The photocatalytic efficiency was evaluated under UV and visible irradiations in aqueous solution using methyl orange (MO) as an organic pollutant probe molecule. The results showed that, under visible light, the MO degradation increased significantly by doping ZnO (10 %Co-ZnO: 33.2 %; 10 %NiZnO: 19.8 % and 10 %Cu-ZnO: 52.5 %) by comparison with undoped ZnO (9.3 %). The important increase in photocatalytic activity observed for the doped ZnO by comparison with pure ZnO, particularly for 10 %Cu-ZnO, has been linked to a synergistic effect of both the band gap narrowing and the increase in the lifetime of photogenerated charge carriers.

Abstract Cancer is still one of the most challenging diseases to treat, making the pursuit for novel molecules with potential anticancer activity an important research topic. Herein, we have performed a comparative investigation into the anticancer activity of analogs of marine coelenterazine and coelenteramine. The former is a well-known bioluminescent substrate, while the latter is a metabolic product of the resulting bioluminescent reaction. While both types of analogs showed anticancer activity toward lung and gastric cancer cell lines, we have obtained data that highlight relevant differences between the activity of these two types of compounds. More specifically, we observed relevant differences in structure-activity relationships between these types of compounds. Also, coelenteramine analogs showed time-dependent activity, while coelenterazine-based compounds usually present time-independent activity. Coelenterazine analogs also appear to be relatively safer toward noncancer cells than coelenteramine analogs. There was also seen a correlation between the activity of the coelenterazine-based compounds and their light-emission properties. Thus, these results further indicate the potential of the marine coelenterazine chemi-/bioluminescent system as a source of new molecules with anticancer activity, while providing more insight into their modes of action.

Abstract Urban agricultural soils have important social, environmental, and economic roles in big cities, contributing to their sustainability. However, food production in urban soils may be compromised due to soil pollution that resulted from decades of industrial, non-regulated environmental activity and mobile transport. In this study, 12 soils from the urban agricultural area of Rome (Italy) were analyzed for the potentially toxic elements (PTEs) Be, Ba, Pb, Co, Ni, V, Zn, Hg, Cd, As, Cu, and Cr. All but one of the soils under analysis were characterized by at least one PTE concentration above the threshold limit defined by the D.Lgs 152/06 for agricultural soils. Multivariate analysis showed that the soils could be classified into five clusters: clusters I and II had relatively lower mean PTE concentrations; clusters III, IV, and V had relatively higher mean PTE concentrations with several PTE concentrations above the threshold proposed by ILD. Three factors contributing to the variability of the PTE's concentration in the soils under investigation were identified: a geological factor related to PTE As, Ba, Be, and V; an anthropogenic factor related to Pb and Cu; and a mixed factor related to Co, Cr, Ni, and Zn. High PTE content may limit the utilization of urban soils for food production.

Abstract <jats:p>Urban gardens have important social, environmental and economic roles in big cities, contributing to their sustainability. However, food production in urban gardens may be compromised due to soil pollution that resulted from decades of industrial non-regulated environmental activity and mobile transport. In this study, 12 soils from the urban agricultural area of Rome (Italy) were analyzed for the metals Be, Ba, Pb, Co, Ni, V, Zn, Hg, Cd, As, Cu, and Cr. All but one of the soils under analysis were characterized by at least one metal concentration above the threshold limit defined by the Italian Legislative Decree 152/2006 (ILD) for agricultural soils. Multivariate analysis showed that the soils could be classified into five clusters: clusters I and II had relatively lower mean metal concentrations; clusters III, IV, and V had relatively higher mean metal concentrations with several metal concentrations above the threshold proposed by ILD. Three factors contributing to the variability of the metal’s concentration in the soils under investigation were identified: geological factor, related with metals As, Ba, Be, and V; anthropogenic factor, related with Pb and Cu; and, a mixed factor related with Co, Cr, Ni, and Zn. High metal content may limit the utilization of urban soils as urban gardens for food production.</jats:p>