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1.
Materials (Basel) ; 17(13)2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38998250

RESUMO

Water pollution is a major environmental challenge. Due to the inefficiency of conventional wastewater treatment plants in degrading many organic complex compounds, these recalcitrant pollutants end up in rivers, lakes, oceans and other bodies of water, affecting the environment and human health. Semiconductor photocatalysis is considered an efficient complement to conventional methods, and the use of various nanomaterials for this purpose has been widely explored, with a particular focus on improving their activity under visible light. This work focuses on developing magnetic and photoactive zinc/magnesium mixed ferrites (Zn0.5Mg0.5Fe2O4) by sol-gel and solvothermal synthesis methods, which are two of the most important and efficient methods used for the synthesis of ferrite nanoparticles. The nanoparticles (NPs) synthesized by the sol-gel method exhibited an average size of 14.7 nm, while those synthesized by the solvothermal method had an average size of 17.4 nm. Both types possessed a predominantly cubic structure and demonstrated superparamagnetic behavior, reaching a magnetization saturation value of 60.2 emu g-1. Due to the high recombination rate of electrons/holes, which is an intrinsic feature of ferrites, surface functionalization with silver was carried out to enhance charge separation. The results demonstrated a strong influence of adsorption and of the deposition of silver. Several optimization steps were performed during synthesis, allowing us to create efficient catalysts, as proved by the almost full removal of the dye malachite green attaining 95.0% (at a rate constant of 0.091 min-1) and 87.6% (at a rate constant of 0.017 min-1) using NPs obtained by the sol-gel and solvothermal methods, respectively. Adsorption in the dark accounted for 89.2% of the dye removal for nanoparticles prepared by sol-gel and 82.8% for the ones obtained by the solvothermal method. These results make mixed zinc/magnesium ferrites highly promising for potential industrial application in effluent photoremediation using visible light.

2.
Toxics ; 12(6)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38922095

RESUMO

In recent years, contaminants of emerging concern have been reported in several environmental matrices due to advances in analytical methodologies. These anthropogenic micropollutants are detected at residual levels, representing an ecotoxicological threat to aquatic ecosystems. In particular, the pharmacotherapeutic group of non-steroidal anti-inflammatories (NSAIDs) is one of the most prescribed and used, as well as one of the most frequently detected in the aquatic environment. Bivalves have several benefits as a foodstuff, and also as an environment bioindicator species. Therefore, they are regarded as an ideal tool to assess this issue from both ecotoxicological and food safety perspectives. Thus, the control of these residues in bivalves is extremely important to safeguard environmental health, also ensuring food safety and public health. This paper aims to review NSAIDs in bivalves, observing their consumption, physicochemical characteristics, and mechanisms of action; their environmental occurrence in the aquatic environment and aquatic biota; and their effects on the ecosystem and the existent legal framework. A review of the analytical methodologies for the determination of NSAIDs in bivalves is also presented.

3.
ACS Appl Eng Mater ; 2(4): 1170-1189, 2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38693992

RESUMO

The expansion of the Internet of Things market and the proliferation of wearable technologies have generated a significant demand for textile-based energy storage systems. This work reports the engineered design of hybrid electrode nanomaterials of N-doped carbon nanotubes (CNT-N) functionalized with two types of manganese oxides (MOs)-birnessite (MnO2) and hausmannite (Mn3O4)-and their application in solid-state textile-based hybrid supercapacitors (SCs). A versatile citric acid-mediated eco-friendly one-pot aqueous precipitation process is proposed for the fabrication of the hybrids. Remarkably, different types of MOs were obtained by simply changing the reaction temperature from room temperature to 100 °C, without any post-thermal treatment. Asymmetric textile SCs were developed using cotton fabrics coated with CNT-N and the hybrids as textile electrodes, and poly(vinyl) alcohol/orthophosphoric acid as the solid-gel electrolyte. The asymmetric devices presented enhanced energy storage performance relative to the symmetric device based on CNT-N and excellent cycling stability (>96%) after 8000 charge/discharge cycles owing to synergistic effects between CNT-N and the MOs, which endowed nonfaradaic and pseudocapacitive features to the SCs. The asymmetric SC based on CNT-N@MnO2 featured 47% higher energy density and comparable power density to the symmetric CNT-N-based device (8.70 W h cm-2 at 309.01 µW cm-2 vs. 5.93 W h cm-2 at 346.58 µW cm-2). The engineered hybrid CNT-N@MO nanomaterials and the eco-friendly citric acid-assisted one-pot precipitation route open promising prospects not only for energy storage, but also for (photo)(electro)catalysis, wastewater treatment, and (bio)sensing.

4.
Polymers (Basel) ; 15(22)2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-38006116

RESUMO

Gold nanoclusters (AuNCs) with fluorescence in the Near Infrared (NIR) by both one- and two-photon electronic excitation were incorporated in mesoporous silica nanoparticles (MSNs) using a novel one-pot synthesis procedure where the condensation polymerization of alkoxysilane monomers in the presence of the AuNCs and a surfactant produced hybrid MSNs of 49 nm diameter. This method was further developed to prepare 30 nm diameter nanocomposite particles with simultaneous NIR fluorescence and superparamagnetic properties, with a core composed of superparamagnetic manganese (II) ferrite nanoparticles (MnFe2O4) coated with a thin silica layer, and a shell of mesoporous silica decorated with AuNCs. The nanocomposite particles feature NIR-photoluminescence with 0.6% quantum yield and large Stokes shift (290 nm), and superparamagnetic response at 300 K, with a saturation magnetization of 13.4 emu g-1. The conjugation of NIR photoluminescence and superparamagnetic properties in the biocompatible nanocomposite has high potential for application in multimodal bioimaging.

5.
Antibiotics (Basel) ; 12(5)2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37237816

RESUMO

The presence of pharmaceuticals in aquatic ecosystems mostly originates from wastewater treatment plants (WWTPs) and such a situation can be responsible for significant negative impacts on natural ecosystems, such as estuarine and coastal areas. Bioaccumulation of pharmaceuticals, namely antibiotics, in exposed organisms is known to have remarkable effects on different trophic levels of non-target organisms such as algae, invertebrates and vertebrates, including the emergence of bacterial resistance. Bivalves are a highly appreciated seafood product, as they are fed by filtering water, and can bioconcentrate chemicals, being ideal for biomonitoring environmental health hazards in coastal and estuarine ecosystems. To use this sentinel species, an analytical strategy was developed to be used in accessing antibiotics, from human and veterinary medicine, and evaluate their occurrence as emerging pollutants in aquatic environments. The optimized analytical method was fully validated according to the European requirements defined by the Commission Implementing Regulation 2021/808. The validation comprised the following parameters: specificity, selectivity, precision, recovery, ruggedness, linearity, and the decision limit CCα, as well as the limit of detection (LoD) and limit of quantification (LoQ). The method was validated for 43 antibiotics to allow their quantification in both contexts, environmental biomonitoring and food safety.

6.
ACS Biomater Sci Eng ; 9(6): 3712-3722, 2023 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-37256830

RESUMO

Triboelectric nanogenerators (TENGs) are associated with several drawbacks that limit their application in the biomedical field, including toxicity, thrombogenicity, and poor performance in the presence of fluids. By proposing the use of a hemo/biocompatible hydrogel, poly(2-hydroxyethyl methacrylate) (pHEMA), this study bypasses these barriers. In contact-separation mode, using polytetrafluoroethylene (PTFE) as a reference, pHEMA generates an output of 100.0 V, under an open circuit, 4.7 µA, and 0.68 W/m2 for an internal resistance of 10 MΩ. Our findings unveil that graphene oxide (GO) can be used to tune pHEMA's triboelectric properties in a concentration-dependent manner. At the lowest measured concentration (0.2% GO), the generated outputs increase to 194.5 V, 5.3 µA, and 1.28 W/m2 due to the observed increase in pHEMA's surface roughness, which expands the contact area. Triboelectric performance starts to decrease as GO concentration increases, plateauing at 11% volumetric, where the output is 51 V, 1.76 µA, and 0.17 W/m2 less than pHEMA's. Increases in internal resistance, from 14 ΩM to greater than 470 ΩM, ζ-potential, from -7.3 to -0.4 mV, and open-circuit characteristic charge decay periods, from 90 to 120 ms, are all observed in conjunction with this phenomenon, which points to GO function as an electron trapping site in pHEMA's matrix. All of the composites can charge a 10 µF capacitor in 200 s, producing a voltage between 0.25 and 3.5 V and allowing the operation of at least 20 LEDs. The triboelectric output was largely steady throughout the 3.33 h durability test. Voltage decreases by 38% due to contact-separation frequency, whereas current increases by 77%. In terms of pressure, it appears to have little effect on voltage but boosts current output by 42%. Finally, pHEMA and pHEMA/GO extracts were cytocompatible toward fibroblasts. According to these results, pHEMA has a significant potential to function as a biomaterial to create bio/hemocompatible TENGs and GO to precisely control its triboelectric outputs.


Assuntos
Eletrônica Médica , Hidrogéis , Elétrons , Poli-Hidroxietil Metacrilato
7.
Toxins (Basel) ; 15(4)2023 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-37104229

RESUMO

Rice is the second most important cereal crop and is vital for the diet of billions of people. However, its consumption can increase human exposure to chemical contaminants, namely mycotoxins and metalloids. Our goal was to evaluate the occurrence and human exposure of aflatoxin B1 (AFB1), ochratoxin A (OTA), zearalenone (ZEN), and inorganic arsenic (InAs) in 36 rice samples produced and commercialized in Portugal and evaluate their correlation. The analysis of mycotoxins involved ELISA, with limits of detection (LODs) of 0.8, 1 and 1.75 µg kg-1 for OTA, AFB1, and ZEN, respectively. InAs analysis was carried out by inductively coupled plasma mass spectrometry (ICP-MS; LOD = 3.3 µg kg-1). No sample showed contamination by OTA. AFB1 was present in 2 (4.8%) samples (1.96 and 2.20 µg kg-1), doubling the European maximum permitted level (MPL). Concerning ZEN, 88.89% of the rice samples presented levels above the LOD up to 14.25 µg kg-1 (average of 2.75 µg kg-1). Regarding InAs, every sample presented concentration values above the LOD up to 100.0 µg kg-1 (average of 35.3 µg kg-1), although none surpassed the MPL (200 µg kg-1). No correlation was observed between mycotoxins and InAs contamination. As for human exposure, only AFB1 surpassed the provisional maximum tolerable daily intake. Children were recognized as the most susceptible group.


Assuntos
Micotoxinas , Oryza , Zearalenona , Criança , Humanos , Micotoxinas/análise , Oryza/química , Projetos Piloto , Portugal , Contaminação de Alimentos/análise , Zearalenona/análise , Aflatoxina B1/análise , Medição de Risco
8.
Nanomaterials (Basel) ; 13(6)2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36985945

RESUMO

Late diagnosis and systemic toxicity associated with conventional treatments make oncological therapy significantly difficult. In this context, nanomedicine emerges as a new approach in the prevention, diagnosis and treatment of cancer. In this work, pH-sensitive solid magnetoliposomes (SMLs) were developed for controlled release of the chemotherapeutic drug doxorubicin (DOX). Shape anisotropic magnetic nanoparticles of magnesium ferrite with partial substitution by calcium (Mg0.75Ca0.25Fe2O4) were synthesized, with and without calcination, and their structural, morphological and magnetic properties were investigated. Their superparamagnetic properties were evaluated and heating capabilities proven, either by exposure to an alternating magnetic field (AMF) (magnetic hyperthermia) or by irradiation with near-infrared (NIR) light (photothermia). The Mg0.75Ca0.25Fe2O4 calcined nanoparticles were selected to integrate the SMLs, surrounded by a lipid bilayer of DOPE:Ch:CHEMS (45:45:10). DOX was encapsulated in the nanosystems with an efficiency above 98%. DOX release assays showed a much more efficient release of the drug at pH = 5 compared to the release kinetics at physiological pH. By subjecting tumor cells to DOX-loaded SMLs, cell viability was significantly reduced, confirming that they can release the encapsulated drug. These results point to the development of efficient pH-sensitive nanocarriers, suitable for a synergistic action in cancer therapy with magnetic targeting, stimulus-controlled drug delivery and dual hyperthermia (magnetic and plasmonic) therapy.

9.
Foods ; 12(6)2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36981152

RESUMO

The poultry industry, in order to prevent and control coccidiosis caused by Eimeria spp., widely uses coccidiostats as feed additives. The main objective of this study was to evaluate the presence of nine coccidiostats in 62 egg samples by UHPLC-MS/MS. Overall, detection frequency and average concentration were 90.3% (56/62) and 106.3 µg kg-1, respectively. Only diclazuril and nicarbazin were detected. Diclazuril, only found in home-raised eggs, showed an overall detection frequency of 8.1% (5/62), with average and maximum concentrations of 0.46 ± 1.90 µg kg-1 and 13.6 µg kg-1, respectively. Nicarbazin presented an overall higher frequency, 88.7% (55/62), with levels up to 744.8 µg kg-1. Additionally, four samples (6.5%) presented both nicarbazin and diclazuril. Home-raised egg samples (n = 28) showed a detection frequency of 89.3%, with nicarbazin found in more samples (85.7% vs. 17.9%) and at higher levels (266.3 ± 169.4 µg kg-1 vs. 0.91 ± 2.78 µg kg-1) when compared to diclazuril. In supermarket samples (n = 34), only nicarbazin was detected in 31 samples (91.1%), with an average of 167.6 ± 62.2 µg kg-1. Considering the average contamination scenario, consumers' health should not be adversely affected by egg consumption. In every scenario considered, children were the most vulnerable population group.

10.
Toxicon ; 225: 107051, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36804606

RESUMO

The Azorean dairy industry is based on a semi-intensive model. Due to the few storage facilities and the large climatic fluctuations that characterize the Azores, the complete feed mixture (total mixed ration - TMR) is susceptible to the proliferation of a variety of fungi and mycotoxin contamination. Thus, chronic ingestion of these xenobiotics may lead to increased susceptibility to disease, loss of reproductive performance and, in the case of dairy cattle, decreased productivity and quality of milk produced. Since it is impossible to eliminate completely the presence of mycotoxins, it is essential to ensure the implementation of strategies to reduce their concentration in products intended for food and feed, as well as to monitor and control the levels present in food. This study aimed to evaluate the occurrence zearalenone (ZEA) in feed (TMR) in four dairy cattle farms on the Azorean Island of São Miguel and relate it to the occurrence of this mycotoxin in the milk produced, by associating several production and health indicators translated by the monthly milk contrast. To this end, the monthly milk contrast data, the determination of ZEA in the ingested feed and the (individual) milk samples from the four farms included in the study were used. Eighty-three (98.8%) of the milk samples under study had detectable ZEA levels (1.56 ± 1.36 µg/L), higher than reported in previous similar studies. Although ZEA concentration was not significantly associated with any production indicator analyzed (days in milk, age at calving, milk yield, protein content, butyrate content, somatic cell concentration and urea), it was found that the production regime and type of feed management is a major factor in the exposure of animals to high mycotoxin contents. Further studies are recommended to ensure continued monitoring and reduction of the risk associated with exposure of animals and humans to ZEA.


Assuntos
Micotoxinas , Zearalenona , Humanos , Animais , Bovinos , Fazendas , Ração Animal/análise , Micotoxinas/análise , Leite/química , Medição de Risco
11.
Foods ; 11(18)2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36140870

RESUMO

Coccidiosis remains one of the major problems of the poultry industry. Caused by Eimeria species, Coccidiosis is a contagious parasitic disease affecting poultry with great economic significance. Currently, in order to prevent health problems caused by this disease, broiler farmers make extensive use of coccidiostats in poultry feed, maintaining animal health and, in some cases, enhancing feed conversion. The presence of unauthorized substances, residues of veterinary products and chemical contaminants in the food industry is of concern, since they may pose a risk to public health. As the use of coccidiostats has been increasing without any requirements for veterinary prescription, research and surveillance of coccidiostat residues in poultry meat is becoming imperative. This review presents an up-to-date comprehensive discussion of the state of the art regarding coccidiosis, the most used anticoccidials in poultry production, their mode of action, their prophylactic use, occurrence and the European Union (EU) applicable legislation.

12.
Biomedicines ; 10(7)2022 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-35884856

RESUMO

Multicore magnetic nanoparticles of manganese ferrite were prepared using carboxymethyl dextran as an agglutinating compound or by an innovative method using melamine as a cross-coupling agent. The nanoparticles prepared using melamine exhibited a flower-shape structure, a saturation magnetization of 6.16 emu/g and good capabilities for magnetic hyperthermia, with a specific absorption rate (SAR) of 0.14 W/g. Magnetoliposome-like structures containing the multicore nanoparticles were prepared, and their bilayer structure was confirmed by FRET (Förster Resonance Energy Transfer) assays. The nanosystems exhibited sizes in the range of 250-400 nm and a low polydispersity index. A new antitumor thienopyridine derivative, 7-[4-(pyridin-2-yl)-1H-1,2,3-triazol-1-yl]thieno[3,2-b]pyridine, active against HeLa (cervical carcinoma), MCF-7 (breast adenocarcinoma), NCI-H460 (non-small-cell lung carcinoma) and HepG2 (hepatocellular carcinoma) cell lines, was loaded in these nanocarriers, obtaining a high encapsulation efficiency of 98 ± 2.6%. The results indicate that the new magnetoliposomes can be suitable for dual cancer therapy (combined magnetic hyperthermia and chemotherapy).

13.
Polymers (Basel) ; 14(13)2022 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-35808800

RESUMO

Studies that aim to produce flexible films of composite materials based on ionomers-PZT, and volume fractions lower than 10% PZT, in order to monitor damage in aeronautical structures are seldom investigated. The growing emphasis on the use of polymers capable of self-healing after damage or activation by heating has motivated the application of self-healing ionomers as polymeric matrices in composites with piezoelectric particles aiming to monitor damage. Flexible composite films were developed based on the self-healing polymer matrix Surlyn® 8940 ionomer (DuPontTM-Wilmington, DE, USA) and PZT particles (connectivity 2-3) in volume fractions of 1, 3, 5 and 7%, with thickness around 50-100 µm. The choice of PZT volume fractions followed the preliminary requirement that establishes a final density, which is lower or at least close to the density of the materials used in aeronautical structures. Since the application of composites based on epoxy resin/carbon fibers has been increasing in the aeronautical segment, this material (with density lower than 1500 kg/m3) was chosen as a reference for the present work. Thus, due to self-healing (a characteristic of the matrix Surlyn® 8940) combined with recyclability, high flexibility and low thickness, the flexible composite films showed advantages to be applied on aeronautical structures, which present complex geometries and low-density materials. The manufactured films were characterized by SEM, XRD, DMA and mechanical tensile tests. The results were discussed mainly in terms of the volume fraction of PZT. X-ray diffraction patterns showed coexistent rhombohedral and tetragonal phases in the PZT particles-dispersed composite, which can potentialize the alignment of ferroelectric domains during polarization under strong electrical field, enhancing dielectric and piezoelectric properties toward sensing applications. DMA and tensile testing results demonstrated that the addition of PZT particles did not impair either dynamic or quasi-static mechanical performance of the flexible composite films. It was concluded that the PZT volume fraction should be lower than 3% because, for higher values, the molecular mobility of the polymer would suffer significant reductions. These findings, combined with the high flexibility and low density of the ceramic particle-filled thermoplastic polymer, render the developed flexible composite film a very promising candidate for strain and damage sensing in aeronautical structures.

14.
Materials (Basel) ; 15(5)2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35268967

RESUMO

The development of stimuli-sensitive drug delivery systems is a very attractive area of current research in cancer therapy. The deep knowledge on the microenvironment of tumors has supported the progress of nanosystems' ability for controlled and local fusion as well as drug release. Temperature and pH are two of the most promising triggers in the development of sensitive formulations to improve the efficacy of anticancer agents. Herein, magnetic liposomes with fusogenic sensitivity to pH and temperature were developed aiming at dual cancer therapy (by chemotherapy and magnetic hyperthermia). Magnetic nanoparticles of mixed calcium/manganese ferrite were synthesized by co-precipitation with citrate and by sol-gel method, and characterized by X-ray diffraction (XRD), scanning electron microscopy in transmission mode (STEM), and superconducting quantum interference device (SQUID). The citrate-stabilized nanoparticles showed a small-sized population (around 8 nm, determined by XRD) and suitable magnetic properties, with a low coercivity and high saturation magnetization (~54 emu/g). The nanoparticles were incorporated into liposomes of dipalmitoylphosphatidylcholine/cholesteryl hemisuccinate (DPPC:CHEMS) and of the same components with a PEGylated lipid (DPPC:CHEMS:DSPE-PEG), resulting in magnetoliposomes with sizes around 100 nm. Dynamic light scattering (DLS) and electrophoretic light scattering (ELS) measurements were performed to investigate the pH-sensitivity of the magnetoliposomes' fusogenic ability. Two new antitumor thienopyridine derivatives were efficiently encapsulated in the magnetic liposomes and the drug delivery capability of the loaded nanosystems was evaluated, under different pH and temperature conditions.

15.
Toxins (Basel) ; 14(3)2022 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-35324701

RESUMO

Breast milk is considered the ideal form of nutrition for newborns and infants. However, it can carry over contaminants, namely mycotoxins, with biological effects to which this population is particularly vulnerable. Human biomonitoring and surveillance programs are particularly scarce in low-income countries, where food security is a more urgent priority in comparison with food safety. This pilot survey aims to assess exposure of breastfed infants to aflatoxin M1 (AFM1), zearalenone (ZEN), and ochratoxin A (OTA) in Angola, and to evaluate the main socio-demographical and food consumption determinants of lactating mothers. All 37 breast milk samples analyzed are found to be contaminated with ZEN and OTA, although none are found contaminated with AFM1. Contamination levels are lower than previously reported for ZEN but higher in the case of OTA. A significant association between ZEN levels in breast milk and the consumption of cookies by the lactating mothers is found. As for OTA, higher levels are observed in the milk from mothers with younger infants, for which high estimated daily intake (EDI) is determined. As far as the authors are aware, this is the first survey of the occurrence of mycotoxins in breast milk in Angola, so further human biomonitoring works should follow, given that mycotoxins are a global health issue that directly impact the health of populations.


Assuntos
Micotoxinas , Zearalenona , Aflatoxina M1/análise , Angola , Monitoramento Biológico , Feminino , Contaminação de Alimentos/análise , Humanos , Lactente , Recém-Nascido , Lactação , Leite Humano/química , Micotoxinas/análise
16.
J Agric Food Chem ; 69(47): 14287-14293, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34788026

RESUMO

For the first time, this paper aimed to evaluate nine ionophore and synthetic coccidiostat residues in poultry muscle samples, obtained from different production types, by solid-liquid extraction followed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The fully validated methodology was successfully applied to a total of 101 chicken and turkey samples obtained from canteens, supermarkets, and home productions in Portugal. Halofuginone, diclazuril, decoquinate, narasin, lasalocid, and salinomycin were detected in 20.8% of the samples. Home raised samples showed a greater frequency, 47.1%. The synthetic coccidiostats halofuginone, diclazuril, and decoquinate were found in averages of 0.7 µg kg-1,2.9 µg kg-1, and 3.7 µg kg-1, respectively, while averages of 1.2 µg kg-1, 1.6 µg kg-1, and 1.3 µg kg-1 were found regarding the ionophores narasin, lasalocid, and salinomycin. As for the risk assessment, values lower than 8.06% of the acceptable daily intake (ADI) were observed, indicating that exposure to coccidiostats through consumption of poultry meat does not represent risk to consumers.


Assuntos
Coccidiostáticos , Resíduos de Drogas , Animais , Cromatografia Líquida , Resíduos de Drogas/análise , Aves Domésticas , Medição de Risco , Espectrometria de Massas em Tandem
17.
Pharmaceutics ; 13(11)2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34834322

RESUMO

Liposome-like nanoarchitectures containing manganese ferrite nanoparticles covered or decorated with gold were developed for application in dual cancer therapy, combining chemotherapy and photothermia. The magnetic/plasmonic nanoparticles were characterized using XRD, UV/Visible absorption, HR-TEM, and SQUID, exhibiting superparamagnetic behavior at room temperature. The average size of the gold-decorated nanoparticles was 26.7 nm for MnFe2O4 with 5-7 nm gold nanospheres. The average size of the core/shell nanoparticles was 28.8 nm for the magnetic core and around 4 nm for the gold shell. Two new potential antitumor fluorescent drugs, tricyclic lactones derivatives of thienopyridine, were loaded in these nanosystems with very high encapsulation efficiencies (higher than 98%). Assays in human tumor cell lines demonstrate that the nanocarriers do not release the antitumor compounds in the absence of irradiation. Moreover, the nanosystems do not cause any effect on the growth of primary (non-tumor) cells (with or without irradiation). The drug-loaded systems containing the core/shell magnetic/plasmonic nanoparticles efficiently inhibit the growth of tumor cells when irradiated with red light, making them suitable for a triggered release promoted by irradiation.

18.
Rev Sci Instrum ; 92(4): 043904, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-34243363

RESUMO

A custom setup for Seebeck coefficient and electrical resistivity measurements of thin films as a function of temperature in the range of 10-300 K was developed. The Seebeck coefficient is measured using a two-probe arrangement and using either a dynamical or steady/quasi-steady differential method. The temperature differences (ΔTs) for these measurements across the samples are achieved by using resistive heaters embedded in two copper blocks. The sample is screwed to these blocks and is in pressured contact with the measurement probes. The electrical resistivity is measured with a two-probe arrangement. To verify the reliability of the developed setup, measurement tests were performed on commercial niobium foil and a specular spin valve previously studied, having obtained a great accordance (within ∼3%) between this setup's experimental results and the reference measurements.

19.
Dalton Trans ; 50(29): 9983-10013, 2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34264261

RESUMO

The worldwide energy scarcity arising from the massive consumption of nonrenewable energy sources raised a global awareness of the need for cleaner and affordable energy solutions to mitigate climate change and ensure the world sustainable development. The rise of the Internet of Things and the fast growth of the groundbreaking market of wearable electronics boosted a major quest for self-powered technologies merging energy harvesting and energy storage functionalities to meet the demands of a myriad of market segments, such as healthcare, transportation, defense and sports. Thermoelectric devices are a green energy harvesting solution for wearable electronics since they harness the low-grade waste heat from ubiquitous thermal energy sources and convert it into electrical energy. However, these systems generate electrical energy in an intermittent manner, depend on the local heat release availability and require an additional unit to store energy. Flexible and wearable supercapacitors are a safe and eco-friendly energy storage solution to power wearables, offering advantages of security, longer cycle life, higher power density and faster charging over batteries. However, an additional unit that generates energy or that is able to charge the storage device is required. More recently, a new class of all-in-one thermally-chargeable supercapacitors blossomed to meet the requirements of the next generation of autonomous wearable electronics and ensure an endurable energy supply. This self-chargeable hybrid technology combines the functionalities of thermal energy harvesting and supercapacitive energy storage in a single multitasking device. In this Perspective, the advances in the burgeoning field of all-in-one thermally-chargeable supercapacitors for flexible/wearable applications will be critically examined, ranging from their structure and working principle to the rational design of the composing materials and of tailor-made architectures. It will start by introducing the foundations of single flexible/wearable thermoelectric generators and supercapacitors and will evolve into the pioneering venture of fully-integrated thermal energy harvesting/storage systems. It will end by highlighting the current bottlenecks and future pathways for advancing the development of this sophisticated smart technology.


Assuntos
Fontes Geradoras de Energia , Dispositivos Eletrônicos Vestíveis , Fontes de Energia Elétrica , Eletrodos , Temperatura Alta
20.
Artigo em Inglês | MEDLINE | ID: mdl-34077331

RESUMO

Carmines (E120) are used worldwide as natural food colouring agents of animal origin, with a widespread application, including yoghurts. Despite being considered safe for human health, carmines are known to cause allergic reactions. Our goal was to evaluate the presence of carmines in different yoghurts with a label declaration of E120, purchased in Portugal, and, for the first time, to assess the human risk. The analytical methodology, recommended by JECFA, was based on acid hydrolysis of the samples followed by spectrophotometric UV-Vis analysis at 494 nm. This methodology allowed for a limit of quantification (LOQ) of 39.0 mg/kg and recovery rates higher than 97.7%. All the samples had carmines at levels above the LOQ, ranging between 43.8 and 193.8 mg/kg, with an average of 125.2 ± 34.5 mg/kg. In total, 8 (26.7%) samples exceeded the European Union (EU) maximum permitted level (MPL) established for carmines in this foodstuff, 150 mg/kg. Solid yoghurts presented higher average levels, 137.2 mg/kg, when compared to liquid samples, 107.2 mg/kg, with a significant statistical difference (p= 0.0236) being observed. No significant statistical difference was observed between white and private labels, whose average levels were very similar, 125.4 vs 125 mg/kg, respectively. Although some samples were above the allowable values, the estimated daily intake (EDI), designed for the different scenarios of different yoghurt types, did not exceed the established ADI, 5 mg/kg bw/day. According to the obtained results, carmine ingestion through the consumption of yoghurt poses low risk to the Portuguese consumers. However, children were the most vulnerable population group with a calculated risk value of up to 10% considering the mean content scenario. These first findings point out the need to reinforce surveillance programmes and monitoring studies, contributing to an increased awareness regarding carmine exposure, however it must be emphasised that yoghurt has evident nutritional benefits depending on a healthful consumer choice.


Assuntos
Carmim/análise , Corantes de Alimentos/análise , Iogurte/análise , Peso Corporal , Carmim/efeitos adversos , Ingestão de Alimentos , Corantes de Alimentos/efeitos adversos , Humanos , Portugal , Medição de Risco , Espectrofotometria/métodos
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