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Energy security and environmental concerns, related to the increasing carbon emissions, have prompted in the last years the search for renewable and sustainable fuels. Biodiesel, a mixture of fatty acids alkyl esters shows properties, which make it a feasible substitute for fossil diesel. Biodiesel can be produced using different processes and different raw materials. The most common, first generation, biodiesel is produced by methanolysis of vegetable oils using basic or acid homogeneous catalysts. The use of vegetable oils for biodiesel production raises serious questions about biodiesel sustainability. Used cooking oils and animal fats can replace the vegetable oils in biodiesel production thus allowing to produce a more sustainable biofuel. Moreover, methanol can be replaced by ethanol being totally renewable since it can be produced by biomass fermentation. The substitution of homogeneous catalyzed processes, nowadays used in the biodiesel industry, by heterogeneous ones can contribute to improve the biodiesel sustainability with simultaneous cost reduction. From the existing literature on biodiesel production, it stands out that several strategies can be adopted to improve the sustainability of biodiesel. A literature review is presented to underline the strategies allowing to improve the biodiesel sustainability.

Current industrial methods of biodiesel production lead to an excess of crude glycerin which requires costly purification before commercialization. Production of oxygenated fuel additives is a potential route for glycerin valorization. Glycerin acetylation was carried out over heterogeneous acid catalysts (15%, glycerol weight basis) using glacial acetic acid (molar ratio = 9). The catalysts, containing different amounts of phosphate species (P/Si from 10 to 20 atomic ratio), were prepared by wet impregnation of commercial silica with aqueous solutions of diammonium phosphate and ortho-phosphoric acid. X-ray diffraction patterns of calcined solids presented amorphous patterns like raw silica. The prepared catalysts presented, at 120 °C, glycerol conversion higher than 89.5% after 1 h of reaction, been diacetin the major product, with triacetin selectivities lower than 26.1%. Diacetin selectivity was found to be almost invariant with catalyst acidity thus underlining the relevance of catalyst porosity due to the large acetins molecules sizes. The slow rate of triacetin diffusion in narrow pores of catalyst might be responsible for the relatively low yield obtained. Surface phosphate species showed a slow rate of leaching in the reaction medium showing high catalyst stability.

The potential of Scenedesmus obliquus biomass, after treating several wastewaters (WWs) (urban, dairy and brewery industries, cattle and poultry breeding), was evaluated for the production of bio-char, bio-oil and bio-gas, through a pyrolysis process. The experiments were carried out in a fixed bed reactor at a temperature of 748 K during 15 min. The thermochemical behaviour of each microalga was assessed by thermogravimetry analysis and infrared spectroscopy. The bio-oils obtained were also quantified and characterized. The results reveal that (i) all microalgae show a similar thermal degradation behaviour; (ii) microalga grown in urban WW shows a lower percentage of lipids; in dairy and cattle WWs, it shows a high percentage of both proteins and lipids, and in poultry and brewery WWs, it shows a higher carbohydrates content; (iii) the microalga grown in poultry WW shows the lowest protein content, whereas the urban grown microalga showed the highest protein content; (iv) the bio-oil obtained by pyrolysis process showed yields in the range 30–60% (w/w) and showed a high content of aromatic compounds.

Photodynamic therapy has been investigated as an alternative method of killing pathogens in response to the multiantibiotic resistance problem. This study evaluated the photodynamic effect of curcumin on methicillin-resistant Staphylococcus aureus (MRSA) compared to susceptible S. aureus (MSSA) and L929 fibroblasts. Suspensions of MSSA and MRSA were treated with different concentrations of curcumin and exposed to light-emitting diode (LED). Serial dilutions were obtained from each sample, and colony counts were quantified. For fibroblasts, the cell viability subsequent to the curcumin-mediated photodynamic therapy was evaluated using the MTT assay and morphological changes were assessed by SEM analysis. Curcumin concentrations ranging from 5.0 to 20.0 μM in combination with any tested LED fluences resulted in photokilling of MSSA. However, only the 20.0 μM concentration in combination with highest fluence resulted in photokilling of MRSA. This combination also promoted an 80% reduction in fibroblast cell metabolism and morphological changes were present, indicating that cell membrane was the main target of this phototherapy. The combination of curcumin with LED light caused photokilling of both S. aureus strains and may represent an alternative treatment for eradicating MRSA, responsible for significantly higher morbidity and mortality and increased healthcare costs in institutions and hospitals.

Freshwater scarcity is a growing concern, exacerbated by industrial effluents containing dyes and other pollutants that endanger aquatic ecosystems. This study explores the potential of biochar sorbents, derived from renewable seaweed biomass, as a sustainable solution for water decontamination. Seaweed biomass (sargaço), collected from Portuguese seashores, was carbonized at 300 °C and 400 °C to produce biochar. Adsorption experiments with methylene blue (MB) revealed that carbonization at 400 °C, followed by ball milling, significantly enhanced adsorption performance. Langmuir isotherm analysis demonstrated a maximum adsorption capacity of 500 mg MB/g sorbent for the optimized biochar (400 °C, ball milled), with adsorption efficiency improving at elevated temperatures and pH levels up to 12. Infrared reflectance spectra of fresh and post-adsorption biochars confirmed the involvement of π–π interactions and hydrogen bonding in the adsorption mechanism. These findings highlight the potential of seaweed-derived biochar as an effective and eco-friendly solution for water purification.

The aim of this study was to identify the main characteristics of school-based drug prevention programs in Brazil and verify whether these interventions apply the prevention principles suggested hy the National Institute on Drug Abuse (NIDA). A cross-sectional study was conducted using a random national sample of 1,151 public and private school managers. The data were collected using an online questionnaire. Poisson regression was used to identify factors associated with the application of a greater number of prevention principles in the programs. The findings showed that programs were generally sporadic, had an average duration of one semester, incorporated different program models, and primarily directed at students. The most active organization in the delivery of programs was the Military Police. Private schools were shown to be 14% more likely to apply more good practice principles than public schools. Furthermore, programs delivered by school staff, health institutions, or departments of education were more likely to apply more prevention principles. Efforts are needed to improve drug prevention practice in Brazilian schools. Our findings show that, overall, school-based drug prevention programs do not apply the NIDA prevention principles.

A water-energy-food (WEF) nexus assessment supports natural resource management by providing an integrated framework for evaluation and decision-making. The participation of a wide range of stakeholders is essential for achieving environmental, economic, and social sustainability in this framework. This analysis supports the decision-making process of the nexus assessment by facilitating dialogue between stakeholders in order to achieve long term efficiencies, especially in rural landscapes where most of the services connected to WEF securities are provided. We identify the most relevant stakeholders operating in the connection between agricultural practices and the WEF nexus to stimulate their engagement in the nexus governance. The study area was the Atlantic Forest Reserve of Ribeirão das Lajes, Brazil. A stakeholder analysis, generating qualitative data using snowball sampling interviews was applied and, after the identification of stakeholders, an analytical categorization disclosing potential conflicts among them was performed. We obtained a pool of stakeholders from different organizational types, including a large number of public entities at local and state levels. The main threat to the development of the project is considered to be the lack of communication between the parties. We note that the prior identification of this group of stakeholders facilitates this communication, enhancing social representation in the area. Outcomes of this study demonstrate the relevance of stakeholder analysis in nexus governance for integrated natural resource management.

Biodiesel can substitute for conventional diesel fuel and contribute to the decarbonization of the transportation sector. To improve biodiesel sustainability and decrease production costs, low-grade fats such as non-edible animal fats must be used. Animal fats are mixed with tissues which must be removed before alcoholysis to avoid biodiesel contamination with nitrogen and phosphorus-containing compounds. Biodiesel was produced by the methanolysis of beef tallow and beef tallow/soybean oil mixtures over calcium heterogeneous catalysts obtained by the calcination of scallop shells. The tallow from fatty bovine tissues was extracted using boiling water, dry microwave treatment, and acetone extraction. The thermal stability and the moisture content of the extracted fats were evaluated by thermogravimetry. The thermograms of fats revealed that microwave treatment, which was faster (3 min instead of 40 min for boiling water and 240 min for acetone extraction) and had the lowest energy consumption, led to a dry fat with a thermal stability analogous to that of fats extracted with boiling water and acetone. All the extracted fats behaved similarly in the methanolysis reaction over calcium catalyst, with biodiesel yield (61–62%) being 30% lower than the analogous obtained from soybean oil (88%). Co-processing the extracted tallow with soybean oil overcomes the drawback related to the low-grade fats.

Background This study aimed to evaluate the survival rate of glass hybrid restorations placed under the atraumatic restorative treatment (ART) technique in first permanent molars affected by molar incisor hypomineralization (MIH). Methods Sixty teeth with severe MIH associated to carious dentin lesions without pulp involvement were included. Treatments were performed by one trained dentist using the ART approach and restored with a glass hybrid restorative system (Equia Forte, GC®) on school premises. Treatments were evaluated after 6 and 12 months by an independent examiner using the modified ART criterion. Data analysis involved descriptive statistics and actuarial success analysis. Results The sample comprised 24 (54.54%) girls and 20 (45.45%) boys with a mean age of 10.55 (±1.25) years. In regard to the number of surfaces involved in the restorations, 29 (48.3%) comprised one surface and 31 (51.7%) two or more surfaces. Considering cavity extent, 25 (41%) presented dentin cavitation without cusp weakness, 23 (37.7%) with large dentin cavitation with cusp weakness and 13 (21.3%) with large dentin cavitation with the breakdown of one or more cusps. Only 4 teeth required local anesthesia. A success rate of 98.3% after 6 and 12 months was observed, as only one restoration failed. The only failure occurred in a restoration involving three or more sur-faces presenting the breakdown of all cusps. Conclusion Restorations using a glass hybrid restorative system and performed in the field with the ART technique proved, after 12 months of evaluation, to be an effective approach to preserving first permanent molars affected by MIH. Trial registration REBEC-RBR-8drccq (17/06/15).

Biodiesel from waste frying oil was produced via methanolysis using biochar-based catalysts prepared by carbonizing banana peels (350 °C and 400 °C) mixed with 20% (wt.) of alkali carbonates (Na, Li, or K). The catalysts exhibited a bi-functional character: acidic and basic. Raman spectroscopy confirmed the alkali’s role in char graphitization, influencing morphology and oxygen content. Oxygenated surface sites acted as acidic sites for free fatty acid esterification, while alkali sites facilitated triglyceride transesterification. The best catalyst obtained by carbonization at 350 °C, without alkali modifier, led to 97.5% FAME by processing a waste frying oil with 1.2 mg KOH/g oil acidity. Most of the studied catalysts yielded high-quality glycerin, allowing the significance of homogenous catalyzed processes to be discarded.