2025
Authors
Pitruzzella, R; Silva, A; RIBEIRO, J; Mendes, J; Coelho, L; Pasquardini, L; Seggio, M; MARZANO, C; Arcadio, F; Cicatiello, D; Zeni, L; Jorge, PAS; Cennamo, N;
Publication
Biomedical Optics Express
Abstract
2025
Authors
Araújo, AC; Ribeiro, JA; Azenha, M; Marques, EF; Oliveira, IS;
Publication
WASTE AND BIOMASS VALORIZATION
Abstract
Hydroponics is an advanced agricultural technique that involves growing plants without soil. Instead, plants are cultivated in a nutrient-rich water solution that provides all the essential minerals they need to thrive, allowing plants to grow either with their roots directly in the solution or supported by inert substrates like pine bark, coconut husk fiber, and rice husk. The solid waste generated from hydroponic cultivation is valuable due to its low cost, abundance, biodegradability, and renewability. These residues are rich in lignocellulosic materials, which can be extracted and refined to produce cellulose and nanocellulose (NC). In this work, cellulose and nanocellulose were extracted from residues of coconut husk fiber and a mixture of pine bark and coconut husk fiber, used in tomato and strawberry hydroponics, respectively. The residues were ground, washed, and chemically treated to obtain cellulose and NC. The chemical process involved several stages: (i) acid treatment, alkaline treatment, and bleaching to isolate cellulose, and (ii) acid hydrolysis followed by ultrasonication to obtain NC. Both materials underwent characterization using various techniques such as TGA, DSC, XRD and FTIR-ATR, which confirmed very low levels of lignin and hemicellulose. Morphological characterization through SEM revealed the presence of micro- and nano-crystals in the cellulose and NC samples, respectively, highlighting the effectiveness of the extraction method. The high purity and quality of the extracted materials make them competitive with commercially available products, suitable for applications in healthcare, food packaging, and automotive industries, while supporting recycling and reuse principles.
2025
Authors
Monteiro, M; Santos, P; Marques, JE; Flores, D; Azenha, M; Ribeiro, JA;
Publication
POLLUTANTS
Abstract
Active and abandoned mining sites are significant sources of heavy metals and metalloid pollution, leading to serious environmental issues. This study assessed the environmental risks posed by potentially toxic elements (PTEs), specifically arsenic (As) and antimony (Sb), in the Technosols (mining residues) of the former Pej & atilde;o coal mine complex in Northern Portugal, a site impacted by forest wildfires in October 2017 that triggered underground combustion within the waste heaps. Our methodology involved determining the pseudo-total concentrations of As and Sb in the collected heap samples using microwave digestion with aqua regia (ISO 12914), followed by analysis using hydride generation-atomic absorption spectroscopy (HG-AAS). The concentrations of As an Sb ranging from 31.0 to 68.6 mg kg-1 and 4.8 to 8.3 mg kg-1, respectively, were found to be above the European background values reported in project FOREGS (11.6 mg kg-1 for As and 1.04 mg kg-1 for Sb) and Portuguese Environment Agency (APA) reference values for agricultural soils (11 mg kg-1 for As and 7.5 mg kg-1 for Sb), indicating significant enrichment of these PTEs. Based on average Igeo values, As contamination overall was classified as unpolluted to moderately polluted while Sb contamination was classified as moderately polluted in the waste pile samples and unpolluted to moderately polluted in the downhill soil samples. However, total PTE content alone is insufficient for a comprehensive environmental risk assessment. Therefore, further studies on As and Sb fractionation and speciation were conducted using the Shiowatana sequential extraction procedure (SEP). The results showed that As and Sb levels in the more mobile fractions were not significant. This suggests that the enrichment in the burned (BCW) and unburned (UCW) coal waste areas of the mine is likely due to the stockpiling of lithic fragments, primarily coals hosting arsenian pyrites and stibnite which largely traps these elements within its crystalline structure. The observed enrichment in downhill soils (DS) is attributed to mechanical weathering, rock fragment erosion, and transport processes. Given the strong association of these elements with solid phases, the risk of leaching into surface waters and aquifers is considered low. This work underscores the importance of a holistic approach to environmental risk assessment at former mining sites, contributing to the development of sustainable remediation strategies for long-term environmental protection.
2024
Authors
Marta, A; Ferreira, A; Couto, I; Neves, MM; Gomes, M; Oliveira, L; Soares, CA; Menéres, MJ; Lemos, C; Beirao, JM;
Publication
CLINICAL OPHTHALMOLOGY
Abstract
Purpose: Inherited retinal diseases (IRDs) are a group of degenerative disorders of the retina, that can be potentially associated with changes in the anterior segment, but their prevalence and impact are not known. Exploring these concomitant ophthalmologic changes with biomechanical assessment may help identify other non-retina causes of vision loss in these patients, such as corneal ectasia or susceptibility to glaucoma. This study aimed to measure and compare corneal biomechanics in patients with and without IRDs. Methods: A total of 77 patients (154 eyes) with IRD were recruited as the study group. The control group consisted of 77 healthy adults (154 eyes) with matched age and sphere equivalents. All participants underwent a comprehensive assessment including corneal tomography (Pentacam (R)) and biomechanical assessment (Corvis ST (R)). A total of 4 second-generation biomechanical parameters and 3 indexes were collected: Ambrosio Relational Thickness (ARTh), Deflection Amplitude Ratio Max (DARM), Integrated Radius (IR) and Stiffness Parameter at Applanation (SP-A1), the final deviation value D of the Belin/Ambrosio Enhanced Ectasia Display (BADResults: For IRD patients, there was a higher DARM (p < 0.001), lower ARTh (p < 0.001), higher CBI (p < 0.001), higher TBI (p<0.001), and higher BAD-D (p < 0.001) compared to the control group. Regarding discrimination of healthy subjects and IRD patients, ARTh was the most sensitive parameter. Conclusion: The results showed that IRD patients tend to have softer corneal behaviour, compared to eyes without pathology, which may predispose patients to corneal ectasia or glaucoma development. ARTh could be used to screen IRD patients if a non-retina cause of vision loss is suspected.
2024
Authors
Rodrigues, HJB; Cardoso, MP; Miranda, CC; Romeiro, AF; Giraldi, MTR; Silva, AO; Costa, JCWA; Santos, JL; Guerreiro, A;
Publication
2024 LATIN AMERICAN WORKSHOP ON OPTICAL FIBER SENSORS, LAWOFS 2024
Abstract
This paper presents the examination of a planar waveguide sensor featuring a bimetallic layer, revealing its potential applicability across both the visible and infrared spectrums. The bimetallic layer consists of adjacent gold and silver slabs positioned atop the waveguide's core. This arrangement demonstrates the activation of two distinct plasmon resonances, indicating promising prospects for multiparameter sensing applications.
2024
Authors
Cardoso, VHR; Caldas, P; Giraldi, MTR; Cernadas, ML; Fernandes, CS; Frazao, O; Costa, JCWA; Santos, JL;
Publication
MEASUREMENT SCIENCE AND TECHNOLOGY
Abstract
This work addresses the historical development of techniques and methodologies oriented to the measurement of the internal diameter of transparent tubes since the original contributions of Anderson and Barr published in 1923 in the first issue of Measurement Science and Technology. The progresses on this field are summarized and highlighted the emergence and significance of the measurement approaches supported by the optical fiber.
The access to the final selection minute is only available to applicants.
Please check the confirmation e-mail of your application to obtain the access code.