Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 77
Filtrar
1.
Braz J Cardiovasc Surg ; 39(4): e20240138, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38771210

RESUMEN

Congenital heart disease (CHD) affects eight to ten out of every 1,000 births, resulting in approximately 23,057 new cases in Brazil in 2022. About one in four children with CHD requires surgery or other procedures in the first year of life, and it is expected that approximately 81% of these children with CHD will survive until at least 35 years of age. Professionals choosing to specialize in CHD surgery face numerous challenges, not only related to mastering surgical techniques and the complexity of the diseases but also to the lack of recognition by medical societies as a separate subspecialty. Furthermore, families face difficulties when access to services capable of providing treatment for these children. To address these challenges, it is essential to have specialized hospitals, qualified professionals, updated technologies, sustainable industry, appropriate financing, quality assessment systems, and knowledge generation. The path to excellence involves specialization across all involved parties. As we reflect on the importance of Pediatric Cardiovascular Surgery and Congenital Heart Diseases establishing themselves as a subspecialty of Cardiovascular Surgery, it is essential to look beyond our borders to countries like the United States of America and United Kingdom, where this evolution is already a reality. This autonomy has led to significant advancements in research, education, and patient care outcomes, establishing a care model. By following this path in Brazil, we not only align our practice with the highest international standards but also demonstrate our maturity and the ability to meet the specific needs of patients with CHD and those with acquired childhood heart disease.


Asunto(s)
Cardiopatías Congénitas , Humanos , Brasil , Cardiopatías Congénitas/cirugía , Procedimientos Quirúrgicos Cardíacos , Niño , Especialidades Quirúrgicas/organización & administración
2.
Spectrochim Acta A Mol Biomol Spectrosc ; 315: 124291, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38643559

RESUMEN

Pulse-modulated CW laser heat deposition modulates the darkness or the transparency of an aggregated medium in the high signal optical regimen. A recently reported work found that transient optical responses of molecular aggregates can be different depending on whether the sample is excited with a laser wavelength tuned within the absorption band of the monomer or within the absorption band of the aggregates. The different transient responses were attributed to different dynamic processes during the laser-induced disassembling of the molecular aggregates and may have implications in the field of organic electronics and optical devices, such as optical logical gates, optical power limiters and all-optical switching. In this paper laser beams with wavelengths of 663 nm and 532 nm were used to produce sudden changes in the thermodynamic equilibrium of the aggregation states of the ortho-toluidine blue dye, which allowed to observe the occurrence of the avalanche - mediated transient phenomenon in the laser-induced disassembling of ortho-toluidine blue (TBO) aggregates. A double exponential model was adjusted to the registered transient data. The obtained values for the fast components of the transient time responses of ortho-toluidine blue dye, for the studied concentrations, ranged from âˆ¼ 6.5 to 9.5 ms at 532 nm, and from âˆ¼ 43 to 48 ms at 663 nm. A single beam experiment was employed to evaluate the performance of the ortho-toluidine blue dye in a beam power-damping device, driven by the simultaneous and cooperative actions of the laser induced disassembling of aggregated dye units and the thermal lensing effect. It was found that the phenomenon of laser-induced dye disassembling of TBO, acting cooperatively with the thermal lensing effect, damps the laser beam power faster than the thermal lensing phenomenon alone. In addition, the results showed that the speed of the laser beam power-damping is dye dependent.

3.
Zootaxa ; 5405(4): 495-525, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38480173

RESUMEN

The demosponge genus Placospongia includes 13 valid species, of which six occur in the Brazilian Exclusive Economic Zone. In the present study, we describe two new species of Placospongia from Northern (off the Amazon River mouth) and Northeastern Brazilian continental shelf and oceanic islands (i.e., Fernando de Noronha Archipelago), viz., Placospongia beatrizae sp. nov. and Placospongia amphinolastra sp. nov., and redescribe the holotype of Placospongia cristata Boury-Esnault, 1973, a poorly known species. In addition, we revise the Brazilian records of the allegedly cosmopolitan species P. carinata, P. melobesioides and P. intermedia, and provide new records of P. colombiensis and P. ruetzleri from Brazil. We demonstrate that P. carinata sensu Coelho & Mello-Leito and P. intermedia sensu Muricy & Moraes and Jimenez et al. belong in fact to P. ruetzleri, and that P. melobesioides sensu Mothes et al. and Gonzlez-Faras is a new species, described here as Placospongia beatrizae sp. nov. With the description of the two new species and synonymyzation of previous records, six species of Placospongia are currently known in Brazilian waters, two of which are endemic. A key to Placospongia species is also provided.


Asunto(s)
Poríferos , Animales , Brasil
4.
Biosensors (Basel) ; 13(8)2023 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-37622915

RESUMEN

Nifedipine, a widely utilized medication, plays a crucial role in managing blood pressure in humans. Due to its global prevalence and extensive usage, close monitoring is necessary to address this widespread concern effectively. Therefore, the development of an electrochemical sensor based on a glassy carbon electrode modified with carbon nanofibers and gold nanoparticles in a Nafion® film was performed, resulting in an active electrode surface for oxidation of the nifedipine molecule. This was applied, together with a voltammetric methodology, for the analysis of nifedipine in biological and environmental samples, presenting a linear concentration range from 0.020 to 2.5 × 10-6 µmol L-1 with a limit of detection 2.8 nmol L-1. In addition, it presented a good recovery analysis in the complexity of the samples, a low deviation in the presence of interfering potentials, and good repeatability between measurements.


Asunto(s)
Nanopartículas del Metal , Nanofibras , Humanos , Oro , Nifedipino , Carbono , Electrodos
6.
Biosensors (Basel) ; 13(7)2023 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-37504089

RESUMEN

The present study reports the development and application of a flow injection analysis (FIA) system for the simultaneous determination of uric acid (UA) and caffeine (CAF) using cathodically pretreated boron-doped diamond electrode (CPT-BDD) and multiple-pulse amperometry (MPA). The electrochemical profiles of UA and CAF were analyzed via cyclic voltammetry in the potential range of 0.20-1.7 V using 0.10 mol L-1 H2SO4 solution as supporting electrolyte. Under optimized conditions, two oxidation peaks at potentials of 0.80 V (UA) and 1.4 V (CAF) were observed; the application of these potentials using multiple-pulse amperometry yielded concentration linear ranges of 5.0 × 10-8-2.2 × 10-5 mol L-1 (UA) and 5.0 × 10-8-1.9 × 10-5 mol L-1 (CAF) and limits of detection of 1.1 × 10-8 and 1.3 × 10-8 mol L-1 for UA and CAF, respectively. The proposed method exhibited good repeatability and stability, and no interference was detected in the electrochemical signals of UA and CAF in the presence of glucose, NaCl, KH2PO4, CaCl2, urea, Pb, Ni, and Cd. The application of the FIA-MPA method for the analysis of environmental samples resulted in recovery rates ranging between 98 and 104%. The results obtained showed that the BDD sensor exhibited a good analytical performance when applied for CAF and UA determination, especially when compared to other sensors reported in the literature.


Asunto(s)
Cafeína , Ácido Úrico , Cafeína/análisis , Oxidación-Reducción , Electrodos , Técnicas Electroquímicas/métodos
7.
Front Microbiol ; 13: 995521, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36246249

RESUMEN

This study analyzed the antimicrobial and antibiofilm action and cytotoxicity of extract (HEScL) and silver nanoparticles (AgNPs-HEScL) from Syzygium cumini leaves. GC-MS, UV-Vis, EDX, FEG/SEM, DLS and zeta potential assays were used to characterize the extract or nanoparticles. Antimicrobial, antibiofilm and cytotoxicity analyses were carried out by in vitro methods: agar diffusion, microdilution and normal oral keratinocytes spontaneously immortalized (NOK-SI) cell culture. MICs of planktonic cells ranged from 31.2-250 (AgNPs-HEScL) to 1,296.8-10,375 µg/ml (HEScL) for Actinomyces naeslundii, Fusobacterium nucleatum, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Streptococcus oralis, Veillonella dispar, and Candida albicans. AgNPs-HEScL showed antibiofilm effects (125-8,000 µg/ml) toward Candida albicans, Streptococcus mutans and Streptococcus oralis, and Staphylococcus aureus and Staphylococcus epidermidis. The NOK-SI exhibited no cytotoxicity when treated with 32.8 and 680.3 µg/ml of AgNPs-HEScL and HEScL, respectively, for 5 min. The data suggest potential antimicrobial and antibiofilm action of HEScL, and more specifically, AgNPs-HEScL, involving pathogens of medical and dental interest (dose-, time- and species-dependent). The cytotoxicity of HEScL and AgNPs-HEScL detected in NOK-SI was dose- and time-dependent. This study presents toxicological information about the lyophilized ethanolic extract of S. cumini leaves, including their metallic nanoparticles, and adds scientific values to incipient studies found in the literature.

8.
Biosensors (Basel) ; 12(10)2022 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-36290997

RESUMEN

This work reports the development and application of a simple, rapid and low-cost voltammetric method for the determination of 3-methylmorphine at nanomolar levels in clinical and environmental samples. The proposed method involves the combined application of a glassy carbon electrode modified with reduced graphene oxide, chitosan and bismuth film (Bi-rGO-CTS/GCE) via square-wave voltammetry using 0.04 mol L-1 Britton-Robinson buffer solution (pH 4.0). The application of the technique yielded low limit of detection of 24 × 10-9 mol L-1 and linear concentration range of 2.5 × 10-7 to 8.2 × 10-6 mol L-1. The Bi-rGO-CTS/GCE sensor was successfully applied for the detection of 3-methylmorphine in the presence of other compounds, including paracetamol and caffeine. The results obtained also showed that the application of the sensor for 3-methylmorphine detection did not experience any significant interference in the presence of silicon dioxide, povidone, cellulose, magnesium stearate, urea, ascorbic acid, humic acid and croscarmellose. The applicability of the Bi-rGO-CTS/GCE sensor for the detection of 3-methylmorphine was evaluated using synthetic urine, serum, and river water samples through addition and recovery tests, and the results obtained were found to be similar to those obtained for the high-performance liquid chromatography method (HPLC)-used as a reference method. The findings of this study show that the proposed voltammetric method is a simple, fast and highly efficient alternative technique for the detection of 3-methylmorphine in both biological and environmental samples.


Asunto(s)
Quitosano , Grafito , Carbono/química , Bismuto , Acetaminofén , Sustancias Húmicas , Povidona , Cafeína , Límite de Detección , Grafito/química , Electrodos , Dióxido de Silicio , Celulosa , Ácido Ascórbico , Urea , Agua , Técnicas Electroquímicas/métodos
9.
Rev. bras. cir. cardiovasc ; 37(5): 776-779, Sept.-Oct. 2022. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1407291

RESUMEN

ABSTRACT Coronary artery fistula draining into the coronary sinus is a rare vascular malformation, and its diagnosis and clinical manifestations usually occur late. We describe the case of a 72-year-old female patient with dyspnea on exertion (New York Heart Association Class III) associated with palpitations. The transthoracic echocardiogram showed significant tricuspid insufficiency. Cardiac catheterization showed aneurysm of the circumflex coronary artery and fistula of this artery draining into the coronary sinus. The patient underwent fistula ligation and tricuspid valve repair, with excellent surgical results.

10.
Anal Methods ; 14(39): 3859-3866, 2022 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-36129055

RESUMEN

A new electrode was prepared based on functionalized graphene and gold nanoparticles dispersed in a chitosan film. Such an electrochemical sensor determines ofloxacin in the presence of dopamine, paracetamol, and caffeine. Characterization (morphological and electrochemical) was done using scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. The sensor design improved the analytical signal, the electrochemical activity, and the electron transfer rate. Ofloxacin was determined by square-wave voltammetry, with a linear concentration range of 0.10-4.9 µmol L-1 (r = 0.999, LOD = 12 nmol L-1). The proposed sensor showed good repeatability and selectivity and was applied successfully to the determination of ofloxacin in pharmaceutical formulations, synthetic urine, and water river samples. The proposed method proved to be excellent; therefore, it is an alternative method for the determination of ofloxacin.


Asunto(s)
Quitosano , Grafito , Nanopartículas del Metal , Acetaminofén , Cafeína/química , Carbono/química , Dopamina , Electrodos , Oro/química , Grafito/química , Nanopartículas del Metal/química , Ofloxacino , Preparaciones Farmacéuticas , Agua
11.
Anal Methods ; 14(20): 2003-2013, 2022 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-35543344

RESUMEN

The present study reports the synthesis and characterization of hydrophobic deep eutectic solvents (HDES) based on fatty acids and tetrabutylammonium bromide (TBAB) or 1-octanol using Fourier transform infrared spectroscopy, and the analysis of the physicochemical properties (viscosity, density, electrical conductivity, and water content) of these solvents. A carbon paste electrode modified with 6.0% (m/m) decanoic acid and TBAB-based HDES was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. The oxidation peak currents of the proposed electrode were enhanced by its high electrochemical activity, fast electron transfer rate, and high surface area, while a remarkable decrease was observed in the peak potential separation. The electrochemical determination of hydroquinone (H2Q) was carried out using square-wave adsorptive anodic stripping voltammetry (SWAdASV). The electrode response was found to be linear in the H2Q concentration range of 2.5 × 10-6-3.0 × 10-3 mol L-1, with the limit of detection (LOD) of 7.7 × 10-7 mol L-1. The method was successfully applied for H2Q determination in dermatological creams.


Asunto(s)
Carbono , Hidroquinonas , Carbono/química , Disolventes Eutécticos Profundos , Técnicas Electroquímicas/métodos , Electrodos , Hidroquinonas/análisis , Solventes
12.
Braz J Cardiovasc Surg ; 37(5): 776-779, 2022 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-35436077

RESUMEN

Coronary artery fistula draining into the coronary sinus is a rare vascular malformation, and its diagnosis and clinical manifestations usually occur late. We describe the case of a 72-year-old female patient with dyspnea on exertion (New York Heart Association Class III) associated with palpitations. The transthoracic echocardiogram showed significant tricuspid insufficiency. Cardiac catheterization showed aneurysm of the circumflex coronary artery and fistula of this artery draining into the coronary sinus. The patient underwent fistula ligation and tricuspid valve repair, with excellent surgical results.


Asunto(s)
Enfermedad de la Arteria Coronaria , Seno Coronario , Anomalías de los Vasos Coronarios , Fístula , Femenino , Humanos , Anciano , Seno Coronario/diagnóstico por imagen , Seno Coronario/cirugía , Seno Coronario/anomalías , Anomalías de los Vasos Coronarios/complicaciones , Anomalías de los Vasos Coronarios/diagnóstico por imagen , Anomalías de los Vasos Coronarios/cirugía , Angiografía Coronaria/métodos , Fístula/complicaciones , Fístula/diagnóstico , Enfermedad de la Arteria Coronaria/complicaciones
13.
Zootaxa ; 5105(1): 105-130, 2022 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-35391312

RESUMEN

The outer shelf and upper slope region under the influence of the Amazon River mouth harbors an extensive reef system with a rich sponge fauna, but no hexactinellids were recorded in the area so far. In this work, manned submersibles were used to describe for the first time three species of Hexactinellida off the Amazon River mouth: Hyalonema (Cyliconemaoida) alucia sp. nov., Dactylocalyx pumiceus and Claviscopulia facunda. We found two morphotypes of Dactylocalyx pumiceus, suggesting that it may be a complex of cryptic species. The populations of the three species off Par State were sparse, but a large aggregation of D. pumiceus was found off Maranho State from 145 to 230 m depth. These findings indicate that hexactinellid grounds may be more common along the Northern Brazilian continental outer shelf and slope than previously thought.


Asunto(s)
Poríferos , Ríos , Animales , Brasil
14.
J Card Surg ; 37(7): 2162, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35266209

RESUMEN

The use of sutureless valves in infective endocarditis has been previously reported. Singh et al. have reported a single-center successful surgical treated pulmonary endocarditis in two cases with a sutureless bioprosthesis.


Asunto(s)
Estenosis de la Válvula Aórtica , Bioprótesis , Endocarditis , Implantación de Prótesis de Válvulas Cardíacas , Prótesis Valvulares Cardíacas , Válvula Aórtica/cirugía , Estenosis de la Válvula Aórtica/cirugía , Endocarditis/cirugía , Humanos , Diseño de Prótesis , Suturas , Resultado del Tratamiento
15.
Zootaxa ; 5004(2): 251-287, 2021 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-34811307

RESUMEN

Petrosiidae (Haplosclerida, Demospongiae) is characterized by the hard and friable consistency, and an isotropic reticulated skeleton of oxeas/ strongyles. The Brazilian coast and oceanic islands harbor three out of four known genera of Petrosiidae: Neopetrosia de Laubenfels, 1949; Petrosia (Petrosia) Vosmaer, 1885 and Xestospongia de Laubenfels, 1932. A taxonomic survey of samples from several expeditions housed at the Porifera Collection of Museu Nacional, Universidade Federal do Rio de Janeiro, with additional comparative materials obtained from the Museu de Cincias Naturais, Fundao Zoobotnica do Rio Grande do Sul, and Universidade Federal de Pernambuco enabled the description of two new species: P. (P.) revizee sp. nov. and X. dorigo sp. nov. We also recorded a range extention for Neopetrosia proxima and Xestospongia muta, and Xestospongia grayi was synonymized with X. muta. Other species reported from the country are diagnosed, and an identification key for Petrosiidae from Brazil is provided.


Asunto(s)
Expediciones , Poríferos , Animales , Brasil
16.
Mar Environ Res ; 172: 105490, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34628146

RESUMEN

Emerging evidence have been supporting the idea that the better known South Atlantic coral reefs (located between 18°S and 24°S) are now essentially senescent structures that have experienced little or no additional vertical reef growth over the past millennia. This has often coincided with a shift to a dominance of non-coral calcifying organisms becoming the main CaCO3 producers in these high latitude and marginal marine settings. Here, we used Calcification Accretion Units (CAUs) and census-based methods to measure non-coral rates of CaCO3 production on the geologically senescent reef and adjacent rhodolith beds within the southernmost subtropical Atlantic reef (i.e., Queimada Grande Reef, QGR). The reef habitat is currently producing CaCO3 at rates of ∼126 g m-2 yr-1. In contrast, fragments of dead corals skeletons deposited adjacent to the reef over the last ∼2000 years are now colonized by crustose coralline red algae. These form a rhodolith bed that produces CaCO3 at rates of 858 g m-2 yr-1. Our results indicate that, whilst not sufficient to promote active net framework accumulation, CaCO3 production by coralline algae and bryozoans on the QGR appears to be sufficient to at least limit net large-scale erosion of the underlying reef structure, allowing the reef structure to persist in a state close to budgetary stasis. Finally, our results are also of relevance for providing insights regarding the balance of CaCO3 production/dissolution/erosion processes in coral reefs, especially in these less understood marginal reefs.


Asunto(s)
Antozoos , Briozoos , Animales , Carbonato de Calcio , Arrecifes de Coral , Ecosistema
17.
Anal Methods ; 13(38): 4495-4502, 2021 10 08.
Artículo en Inglés | MEDLINE | ID: mdl-34514492

RESUMEN

A modified glassy carbon electrode with carbon black (CB) and gold nanoparticles (AuNPs) within a crosslinked chitosan (CTS) film is proposed in this work. The electroanalytical performance of the modified CB-CTS-AuNPs/GCE has been evaluated towards the voltammetric sensing of ketoconazole (KTO), a widespread antifungal drug. The nanocomposite was characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and electrochemistry experiments. The evaluation of the electrochemical behaviour of KTO on the proposed modified electrode shows an irreversible oxidation process at a potential of +0.65 V (vs. Ag/AgCl (3.0 mol L-1 KCl)). This redox process was explored to carry out KTO sensing using square-wave voltammetry. The analytical curve was linear in the KTO concentration range from 0.10 to 2.9 µmol L-1, with a limit of detection (LOD) of 4.4 nmol L-1 and a sensitivity of 3.6 µA L µmol-1. This modified electrode was successfully applied to the determination of KTO in pharmaceutical formulations and biological fluid samples.


Asunto(s)
Quitosano , Nanopartículas del Metal , Nanocompuestos , Oro , Cetoconazol , Hollín
18.
Zootaxa ; 4950(1): zootaxa.4950.1.1, 2021 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-33903317

RESUMEN

The reef system off the Amazon River mouth extends from Amapá state to Maranhão state along the Brazilian Equatorial Margin, encompassing more than 10,000 km2 of rhodolith beds and high-relief hard structures on the outer shelf and upper slope. This unique hard bottom mosaic is remarkable for being influenced by the turbid and hyposaline plume from the world's largest river, and also for representing a connectivity corridor between the Caribbean and Brazil. Bryozoans were recently recognized as major reef builders in the Southwestern Atlantic, but their diversity off the Amazon River mouth remained unknown. Here, we report on recent collections obtained from 23 to 120 m depth in Northern Brazil. Sixty-five bryozoan taxa were characterized using scanning electron microscopy, including 57, five and three taxa of Cheilostomatida, Cyclostomatida and Ctenostomatida, respectively. Cribrilaria smitti and three genera (Cranosina, Glabrilaria and Thornelya) are new records for Brazil, and 13 new species are herein described: Antropora cruzeiro n. sp., Cranosina gilbertoi n. sp., Cribrilaria lateralis n. sp., Crisia brasiliensis n. sp., Glabrilaria antoniettae n. sp., Micropora amapaensis n. sp., Parasmittina amazonensis n. sp., Plesiocleidochasma arcuatum n. sp., Poricella bifurcata n. sp., Pourtalesella duoavicularia n. sp., Stephanollona domuspusilla n. sp., Therenia dianae n. sp., and Thornelya atlanticoensis n. sp. Our results highlight the biodiversity significance of the Amazon reefs and the need for more comprehensive sampling to clarify the role of bryozoans in modern turbid-zone reefs and rhodolith beds.


Asunto(s)
Briozoos , Animales , Biodiversidad , Briozoos/clasificación , Briozoos/fisiología , Ríos
19.
PLoS One ; 16(2): e0247111, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33617570

RESUMEN

Tropical reefs are declining rapidly due to climate changes and local stressors such as water quality deterioration and overfishing. The so-called marginal reefs sustain significant coral cover and growth but are dominated by fewer species adapted to suboptimal conditions to most coral species. However, the dynamics of marginal systems may diverge from that of the archetypical oligotrophic tropical reefs, and it is unclear whether they are more or less susceptible to anthropogenic stress. Here, we present the largest (100 fixed quadrats at five reefs) and longest time series (13 years) of benthic cover data for Southwestern Atlantic turbid zone reefs, covering sites under contrasting anthropogenic and oceanographic forcing. Specifically, we addressed how benthic cover changed among habitats and sites, and possible dominance-shift trends. We found less temporal variation in offshore pinnacles' tops than on nearshore ones and, conversely, higher temporal fluctuation on offshore pinnacles' walls than on nearshore ones. In general, the Abrolhos reefs sustained a stable coral cover and we did not record regional-level dominance shifts favoring other organisms. However, coral decline was evidenced in one reef near a dredging disposal site. Relative abundances of longer-lived reef builders showed a high level of synchrony, which indicates that their dynamics fluctuate under similar drivers. Therefore, changes on those drivers could threaten the stability of these reefs. With the intensification of thermal anomalies and land-based stressors, it is unclear whether the Abrolhos reefs will keep providing key ecosystem services. It is paramount to restrain local stressors that contributed to coral reef deterioration in the last decades, once reversal and restoration tend to become increasingly difficult as coral reefs degrade further and climate changes escalate.


Asunto(s)
Arrecifes de Coral , Organismos Acuáticos/fisiología , Océano Atlántico , Cambio Climático
20.
Talanta ; 224: 121804, 2021 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-33379030

RESUMEN

The present work reports the development of a sensitive and selective method for ethinylestradiol detection using screen-printed electrode (SPE) modified with functionalized graphene (FG), graphene quantum dots (GQDs) and magnetic nanoparticles coated with molecularly imprinted polymers (mag@MIP). The performance of the mag@MIP sensor was compared with that of a non-molecularly imprinted sensor (mag@NIP). Chemical and physical characterizations of the mag@NIP and mag@MIP sensors were performed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Brunauer-Emmett-Teller (BET) techniques. The electrochemical behavior of the electrodes investigated, which included (mag@MIP)-GQDs-FG-NF/SPE, (mag@NIP)-GQDs-FG-NF/SPE, GQDs-FG-NF/SPE and FG-NF/SPE, was evaluated by cyclic voltammetry. The results obtained show a significant increase in peak current magnitude for (mag@MIP)-GQDs-FG-NF/SPE. Using square wave voltammetry experiments, the efficiency of the (mag@MIP)-GQDs-FG-NF/SPE sensor was also tested under optimized conditions. The linear response range obtained for ethinylestradiol concentration was 10 nmol L-1 to 2.5 µmol L-1, with limit of detection of 2.6 nmol L-1. The analytical signal of the (mag@MIP)-GQDs-FG-NF/SPE sensor suffered no interference from different compounds and the sensor exhibited good repeatability. The proposed sensor was successfully applied for ethynilestradiol detection in river water, serum and urine samples, where recovery rates between 96 to 105% and 97-104% were obtained for environmental and biological samples, respectively.


Asunto(s)
Grafito , Nanopartículas de Magnetita , Impresión Molecular , Puntos Cuánticos , Técnicas Electroquímicas , Electrodos , Etinilestradiol , Límite de Detección , Polímeros Impresos Molecularmente
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...