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Potentially harmful element (PHE) bioavailability is important to environmental contamination and must be checked under several soil conditions. This study aimed to assess Fe, Mn, and PHE uptake by rice (Oryza sativa) grown on flooded and non-flooded Fe tailings collected from the Doce River basin after its collapse in Brazil. After 65 days of sowing, shoots and roots were harvested to determine PHE concentrations. The mean concentrations of Mn in shoots and Fe in the roots of rice grown on the flooded tailings were 2140 mg kg-1 and 15,219 mg kg-1, respectively. Mn was extensively translocated from roots to shoots (translocation factor (TF) = 2). Conversely, Fe accumulated in roots (TF = 0.015) and caused morphological damage to this rice organ. The application of macro and micronutrients lessened Fe toxicity in the roots of rice cultivated on the flooded tailings. The flooding of tailings influenced more Fe accumulation than Mn accumulation by rice plants. The PHE Ag, As, Cd, Ni, Hg, Pb, and Sb exhibited low total concentrations (maximum of 9 mg kg-1 for Ni and a minimum of 0.2 mg kg-1 for Cd, Hg, and Sb), and it was not observed an increase in their availability under tailings flooding conditions.
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Ferro , Manganês , Oryza , Rios , Brasil , Ferro/metabolismo , Inundações , Poluentes do Solo/metabolismo , Monitoramento Ambiental , Raízes de Plantas/metabolismoRESUMO
This research enhances ethanol sensing with Fe-doped tetragonal SnO2 films on glass, improving gas sensor reliability and sensitivity. The primary objective was to improve the sensitivity and operational efficiency of SnO2 sensors through Fe doping. The SnO2 sensors were synthesized using a flexible and adaptable method that allows for precise doping control, with energy-dispersive X-ray spectroscopy (EDX) confirming homogeneous Fe distribution within the SnO2 matrix. A morphological analysis showed a surface structure ideal for gas sensing. The results demonstrated significant improvement in ethanol response (1 to 20 ppm) and lower temperatures compared to undoped SnO2 sensors. The Fe-doped sensors exhibited higher sensitivity, enabling the detection of low ethanol concentrations and showing rapid response and recovery times. These findings suggest that Fe doping enhances the interaction between ethanol molecules and the sensor surface, improving performance. A mathematical model based on diffusion in porous media was employed to further analyze and optimize sensor performance. The model considers the diffusion of ethanol molecules through the porous SnO2 matrix, considering factors such as surface morphology and doping concentration. Additionally, the choice of electrode material plays a crucial role in extending the sensor's lifespan, highlighting the importance of material selection in sensor design.
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This study investigated the novel application of Fe-TiO2-allophane catalysts with 6.0 % w/w of iron oxide and two TiO2 proportions (10 % and 30 % w/w) for degrading atrazine (ATZ) using the heterogeneous dual-effect (HDE) process under sunlight. Comparative analyses with Fe-allophane and TiO2-allophane catalysts were conducted in both photocatalysis (PC) and HDE processes. FTIR spectra reveal the unique hydrous feldspathoids structure of allophane, showing evidence of new bond formation between Si-O groups of allophane clays and iron hydroxyl species, as well as Si-O-Ti bonds that intensified with higher TiO2 content. The catalysts exhibited an anatase structure. In Fe-TiO2-allophane catalysts, iron oxide was incorporated through the substitution of Ti4+ by Fe3+ in the anatase crystal lattice and precipitation on the surface of allophane clays, forming small iron oxide particles. Allophane clays reduced the agglomeration and particle size of TiO2, resulting in an enhanced specific surface area and pore volume for all catalysts. Iron oxide incorporation decreased the band gap, broadening the photoresponse to visible light. In the PC process, TiO2-allophane achieves 90 % ATZ degradation, attributed to radical species from the UV component of sunlight. In the HDE process, Fe-TiO2-allophane catalysts exhibit synergistic effects, particularly with 30 % w/w TiO2, achieving 100 % ATZ degradation and 85 % COD removal, with shorter reaction time as TiO2 percentage increased. The HDE process was performed under less acidic conditions, achieving complete ATZ degradation after 6 h without iron leaching. Consequently, Fe-TiO2-allophane catalysts are proposed as a promising alternative for degrading emerging pollutants under environmentally friendly conditions.
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Using a modified co-precipitation method, 11(2) nm γ-Fe2O3 nanoparticles functionalized with PSSNa [Poly(sodium 4-styrenesulfonate)] saloplastic polymer were successfully synthesized, and their structural, vibrational, electronic, thermal, colloidal, hyperfine, and magnetic properties were systematically studied using various analytic techniques. The results showed that the functionalized γ-Fe2O3/PSSNa nanohybrid has physicochemical properties that allow it to be applied in the magnetic remediation process of water. Before being applied as a nanoadsorbent in real water treatment, a short-term acute assay was developed and standardized using a Daphnia magna biomarker. The ecotoxicological tests indicated that the different concentrations of the functionalized nanohybrid may affect the mortality of the Daphnia magna population during the first 24 h of exposure. A lethal concentration of 533(5) mg L-1 was found. At high concentrations, morphological changes were also seen in the body, heart, and antenna. Therefore, these results suggested the presence of alterations in normal growth and swimming skills. The main changes observed in the D. magna features were basically caused by the PSSNa polymer due to its highly stable colloidal properties (zeta potential > -30 mV) that permit a direct and constant interaction with the Daphnia magna neonates.
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The catalytic properties of three copper complexes, [Cu(en)2](ClO4)2 (1), [Cu(amp)2](ClO4)2, (2) and [Cu(bpy)2](ClO4)2 (3) (where en = ethylenediamine, amp = 2-aminomethylpyridine and bpy = 2,2'-bipyridine), were explored upon the oxidation of benzyl alcohol (BnOH). Maximized conversions of the substrates to their respective products were obtained using a multivariate analysis approach, a powerful tool that allowed multiple variables to be optimized simultaneously, thus creating a more economical, fast and effective technique. Considering the studies in a fluid solution (homogeneous), all complexes strongly depended on the amount of the oxidizing agent (H2O2), followed by the catalyst load. In contrast, time seemed to be statistically less relevant for complexes 1 and 3 and not relevant for 2. All complexes showed high selectivity in their optimized conditions, and only benzaldehyde (BA) was obtained as a viable product. Quantitatively, the catalytic activity observed was 3 > 2 > 1, which is related to the π-acceptor character of the ligands employed in the study. Density functional theory (DFT) studies could corroborate this feature by correlating the geometric index for square pyramid Cu(II)-OOH species, which should be generated in the solution during the catalytic process. Complex 3 was successfully immobilized in silica-coated magnetic nanoparticles (Fe3O4@SiO2), and its oxidative activity was evaluated through heterogenous catalysis assays. Substrate conversion promoted by 3-Fe3O4@SiO2 generated only BA as a viable product, and the supported catalyst's recyclability was proven. Reduced catalytic conversions in the presence of the radical scavenger (2,2,6,6-tetrametil-piperidi-1-nil)oxil (TEMPO) indicate that radical and non-radical mechanisms are involved.
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This study examines household pets as potential epidemiological links between environments contaminated with pathogenic leptospires and humans in Santa Fe, Argentina. The aims of our study were: (a) to characterize the habits and exposure to environmental sources of leptospirosis in the population of dogs and cats attending to municipal spay and neutering campaigns in Santa Fe, Argentina, (b) to assess the seroprevalence of anti-Leptospira antibodies in asymptomatic dogs and cats, (c) to evaluate factors that could increase seropositivity, and (d) to identify spatial clusters of seropositive dogs and cats in the capital city of Santa Fe. From May to November 2022, a cross-sectional serosurvey was conducted during municipal spaying/neutering campaigns. Eligible household dogs and cats were over 6 months old, apparently healthy, and not vaccinated against leptospirosis in the past 6 months. We used microagglutination test (MAT) to assess anti-Leptospira antibodies using a panel of 10 reference strains. We used generalized linear mixed effects models (GLMM) to examine individual and census tract-level risk factors for seropositivity, and local Moran's I statistic for spatial clusters. Results showed higher leptospiral antibody prevalence in dogs (18.2â¯%) than cats (3.6â¯%, p = 0.002). Dogs with street access had higher likelihood of being seropositive (OR: 3.8, 95â¯% CI: 1.2; 11.9), and areas with chronic poverty showed an elevated risk of presenting seropositive animals (RR: 4.0, 95â¯% CI: 1.1; 14.4). Spatial analysis didn't reveal significant seropositivity clusters among census tracts. These findings shed light on widespread Leptospira seropositivity in pets in this endemic region. Understanding seroprevalence and risk factors can guide public and veterinary health strategies, emphasizing increased leptospirosis vaccination for dogs in vulnerable areas and promoting responsible pet care.
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Anticorpos Antibacterianos , Doenças do Gato , Doenças do Cão , Leptospira , Leptospirose , Animais , Cães , Gatos , Leptospirose/veterinária , Leptospirose/epidemiologia , Leptospirose/microbiologia , Doenças do Cão/epidemiologia , Doenças do Cão/microbiologia , Doenças do Cão/imunologia , Estudos Soroepidemiológicos , Argentina/epidemiologia , Doenças do Gato/epidemiologia , Doenças do Gato/microbiologia , Leptospira/imunologia , Anticorpos Antibacterianos/sangue , Estudos Transversais , Masculino , Feminino , Fatores de Risco , Prevalência , Doenças Endêmicas/veterinária , Cidades/epidemiologiaRESUMO
In this work, a bibliometric study was carried out to perform a scientific and technological analysis of exchange-spring magnets, an alternative permanent magnet synthesized by reducing or eliminating the use of critical raw materials, such as rare earths. The bibliometric analysis utilized the Scopus database, Orbit-Intellixir, VOSviewer, Orbit-Intelligence and Loglet Lab 4 software for maturity analysis, keyword network representations, charts and graphs for scientific articles and/or patents. A special analysis was performed on nanocomposite and thin-films systems based on Nd-Fe-B, SmCo5 and Mn-Al-C alloys, either mixed or layered with a soft magnetic phase, where relevant information on their magnetic parameters was compilated in tables, highlighting the nanostructured systems that have been exhibited the best permanent magnet properties. The bibliometric analysis revealed that the primary production of scientific articles is concentrated in industrialized countries, and they are predominantly published in journals dedicated to magnetism. A patents analysis showed that Nissan motors is by far the main applicant, with most of its patents is focused on technological domains related to electrical machinery, apparatus, energy and metallurgy. On the other hand, the S-curve of maturity for scientific articles indicated that the study of exchange-spring magnets is entering a mature state. In contrast, patent production, following a bi-logistic model, is in a saturation stage for the second S-curve. Maturity analyses, employing S-curve, bi-logistic and multi-logistic models, were performed on nanocomposites and thin films based on Nd-Fe-B, SmCo5 and Mn-Al-C alloys, respectively. We found that the investigation in Nd-Fe-B-based alloys is close to enter to a scientific saturation stage, while an average growth stage is observed for the SmCo5 and Mn-Al-C-based alloys. This suggests that research on alternative magnets, capable of fulfilling technological applications where a Nd-Fe-B magnets are commonly used, is a topic of significant interest.
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Inaugurado em 2003, o Caminho da Fé (CF) é uma rota de peregrinação de mais de 300 Km. Ele tem início em Águas da Prata/SP e termina na Basílica de Aparecida (Aparecida/SP). Anualmente o CF atrai mais de 40 mil peregrinos, sendo que mais da metade são de cicloturistas. O objetivo deste artigo é analisar como os cicloturistas percebem as paisagens neste caminho. Como metodologia utilizamos: pesquisa qualitativa; observação através de cicloviagens; diário de campo; e, um questionário semiestruturado. Indagamos os cicloturista quanto às paisagens que mais lhes chamavam atenção. Como resultado encontramos respostas que foram em direção as paisagens naturais, destacando-se paisagens olfativas e sonoras, entre outras.
Opened in 2003, the Way of Faith (CF) is a pilgrimage route of more than 300 km. It starts in Águas da Prata/SP, and ends at the Basilica of Aparecida (Aparecida)/SP. Every year the CF CF attracts more than 40 thousand pilgrims, of which more than half are cycle tourists. The objective of this article is to analyze how cycle tourists perceive the landscapes on this path. As methodology we use: qualitative research; observation through cycl trips; field journal; and, a semi-structured questionnaire. We asked cycle tourists about the landscapes that most caught their attention. As a result, we found answers that focused on natural landscapes, highlighting olfactory and sound landscapes, among others.
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Nanostructured materials with controllable properties have been used to cage and release various types of compounds. In the present study, iron-loaded nanostructured sol-gel SiO2-Fe materials were prepared and injected into the rat brain to develop a method for gradual iron delivery into the neurons with the aims to avoid acute iron toxicity and develop an animal model of gradual, metal-induced neurodegeneration. Nanoparticles were prepared by the traditional method of hydrolysis and condensation reactions of tetraethyl orthosilicate at room temperature and subsequent heat treatment at 200 °C. FeSO4 was added in situ during the silica preparation. The resulting materials were characterized by UV-VIS and infrared spectroscopies, X-ray diffraction, and N2 adsorption-desorption. An in vitro ferrous sulfate release test was carried out in artificial cerebrospinal fluid as the release medium showing successful ferrous sulfate loading on nanostructured silica and sustained iron release during the test time of 10 h. Male Wistar rats administered with SiO2-Fe nanoparticles in the substantia nigra pars compacta (SNpc) showed significant intraneuronal increase of iron, in contrast to the animals administered with FeSO4 that showed severe neuronal loss, 72 h post-treatment. Both treatments induced lipid fluorescent product formation in the ventral midbrain, in contrast to iron-free SiO2 and PBS-only injection controls. Circling behavior was evaluated six days after the intranigral microinjection, considered as a behavioral end-point of brain damage. The apomorphine-induced ipsilateral turns in the treated animals presented significant differences in relation to the control groups, with FeSO4 administration leading to a dramatic phenotype, compared to a milder impact in SiO2-Fe administrated animals. Thus, the use of SiO2-Fe nanoparticles represents a slow iron release system useful to model the gradual iron-accumulation process observed in the SNpc of patients with idiopathic Parkinson's disease.
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Given the current and escalating global energy and environmental concerns, this work explores an innovative approach to mitigate a widely employed commercial herbicide using a direct glyphosate (Gly) photocatalytic fuel cell (PFC). The device generates power continuously by converting solar radiation, degrading and mineralizing commercial glyphosate-based fuel, and reducing sodium persulfate at the cathode. Pristine and modified hematite photoanodes were coupled to Pt/C nanoparticles dispersed in a carbon paper (CP) support (Pt/C/CP) dark cathode by using an H-type cell. The Gly/persulfate PFC shows a remarkable current and power generation enhancement after dual-surface modification of pristine hematite with segregated Hf and FeNiOx cocatalysts. The optimized photoanode elevates maximum current density (Jmax) from 0.35 to 0.71 mA cm-2 and maximum power generation (Pmax) from 0.04 to 0.065 mW cm-2, representing 102.85 and 62.50% increase in Jmax and Pmax, respectively, as compared to pristine hematite. The system demonstrated stability over a studied period of 4 h; remarkably, the photodegradation of Gly proved substantial, achieving â¼98% degradation and â¼6% mineralization. Our findings may significantly contribute to reducing Gly's environmental impact in agribusiness since it may convert the pollutant into energy at zero bias. The proposed device offers a sustainable solution to counteract Gly pollution while concurrently harnessing solar energy for power generation.
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The ecotoxic effect of Zn species arising from the weathering of the marmatite-like sphalerite ((Fe, Zn)S) in Allium cepa systems was herein evaluated in calcareous soils and connected with its sulfide oxidation mechanism to determine the chemical speciation responsible of this outcome. Mineralogical analyses (X-ray diffraction patterns, Raman spectroscopy, scanning electron microscopy and atomic force microscopy), chemical study of leachates (total Fe, Zn, Cd, oxidation-reduction potential, pH, sulfates and total alkalinity) and electrochemical assessments (chronoamperometry, chronopotentiometry, cyclic voltammetry, and electrochemical impedance spectroscopy) were carried out using (Fe, Zn)S samples to elucidate interfacial mechanisms simulating calcareous soil conditions. Results indicate the formation of polysulfides (Sn2-), elemental sulfur (S0), siderite (FeCO3)-like, hematite (Fe2O3)-like with sorbed CO32- species, gunningite (ZnSO4·H2O)-like phase and smithsonite (ZnCO3)-like compounds in altered surface under calcareous conditions. However, the generation of gunningite (ZnSO4·H2O)-like phase was predominant bulk-solution system. Quantification of damage rates ranges from 75 to 90% of bulb cells under non-carbonated conditions after 15-30 days, while 50-75% of damage level is determined under neutral-alkaline carbonated conditions. Damage ratios are 70.08 and 30.26 at the highest level, respectively. These findings revealed lower ecotoxic damage due to ZnCO3-like precipitation, indicating the effect of carbonates on Zn compounds during vegetable up-taking (exposure). Other environmental suggestions of the (Fe, Zn)S weathering and ecotoxic effects under calcareous soil conditions are discussed.
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Cebolas , Poluentes do Solo , Compostos de Zinco , Solo/química , Sulfetos/química , Tempo (Meteorologia) , Poluentes do Solo/análiseRESUMO
In this work, the role of the binder volumetric fraction used on the consolidation process of Sm-Fe-N-based bonded magnets obtained via the laser powder bed fusion technique has been investigated and explained. The magnetic samples have been obtained via the Selective Laser Sintering (SLS) process, using a mixture of polyamide-12 powder (PA12, DuraForm PA2200) and isotropic Sm-Fe-N melt-spun ribbons (Daido Electronics, Inc.) as feedstocks. The binder content has been varied between 34% and 65% vol. Geometrical density values increased systematically as the PA12 content was increased, reaching a maximum value of ρ = 3.35 g/cm3 (60% vol.), which represents 89% of a fully dense composite. In this composition, the maximum magnetic properties values have been achieved, Jr = 369 mT and (BH)max = 24 kJ/m3. A further increase on the PA12 fraction up to 65% vol. resulted on magnetic samples with 97% relative density, but at the expense of magnetic performance. The formation of a continuous polymeric matrix has been observed via Scanning Electron Microscopy (SEM) analysis when PA12 fraction was on the interval between 60% and 65% vol., not observable for the other explored conditions. Volumetric binder fractions comparable with other published works, which used spherical particles as raw materials for feedstock production, showed inadequate consolidation and required adjustments for proper densification.
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Magnetic nanoparticles, such as magnetite (Fe3O4), exhibit superparamagnetic properties below 15 nm at room temperature. They are being explored for medical applications, and the coprecipitation technique is preferred for cost-effective production. This study investigates the impact of synthesis temperature on the nanoparticles' physicochemical characteristics. Two types of magnetic analysis were conducted. Samples T 40, T 50, and T 60 displayed superparamagnetic behavior, as evidenced by the magnetization curves. The experiments verified the development of magnetic nanoparticles with an average diameter of approximately dozens of nanometers, as determined by various measurement methods such as XDR, Raman, and TEM. Raman spectroscopy showed the characteristic bands of the magnetite phase at 319, 364, 499, and 680 cm-1. This was confirmed in the second analysis with the ZFC-FC curves, which showed that the samples' blocking temperatures were below ambient temperature. ZFC-FC curves revealed a similar magnetization of about 30 emu/g when applying a magnetic field of 5 kOe.
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α-Fe2O3 and FeMnO3/α-Fe2O3 fibers were successfully prepared via Solution Blow Spinning (SBS). The effect of drying during the SBS process on fiber morphology was evaluated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and N2 adsorption-desorption isotherms. A slow drying promoted continuous fibers with rough surfaces and lower average diameters. However, fast drying enabled the production of fibers with low densification and many surface pores with higher BET-specific surface areas. The porous fibers produced have potential applications in energy generation and storage.
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This study was designed to elucidate the physiological responses of three Lotus forage accessions to alkaline stress, and the influence of inoculating with Pantoea eucalypti endophyte strain on alkaline stress mitigation. A diploid L. corniculatus (Lc) accession, L. tenuis (Lt), and the interspecific hybrid Lt × Lc obtained from these two parental lines were exposed to alkaline stress (pH 8.2). Both Lt and the Lt × Lc hybrid are alkaline-tolerant compared to Lc, based on observations that dry mass was not reduced under stress, and there were no chlorosis symptoms on leaf blades. In all three Lotus accessions, Fe2+ concentration under stress decreased in aerial parts and simultaneously increased in roots. Inoculation with P. eucalypti considerably increased Fe2+ content in shoots of all three Lotus forage species under alkaline treatment. Photochemical efficiency of PSII was affected in Lc accession only when exposed to alkaline treatment. However, when cultivated under alkalinity with inoculation, plants recovered and had photosynthetic parameters equivalent to those in the control treatment. Together, the results highlight the importance of inoculation with P. eucalypti, which contributes significantly to mitigating alkaline stress. All results provide useful information for improving alkaline tolerance traits of Lotus forage species and their interspecific hybrids.
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Lotus , Pantoea , Lotus/fisiologia , Hibridização Genética , FotossínteseRESUMO
Paenibacillus sonchi SBR5T is a Gram-positive, endospore-forming facultative aerobic diazotrophic bacterium that can fix nitrogen via an alternative Fe-only nitrogenase (AnfHDGK). In several bacteria, this alternative system is expressed under molybdenum (Mo)-limiting conditions when the conventional Mo-dependent nitrogenase (NifHDK) production is impaired. The regulatory mechanisms, metabolic processes, and cellular functions of N2 fixation by alternative and/or conventional systems are poorly understood in the Paenibacillus genus. We conducted a comparative proteomic profiling study of P. sonchi SBR5T grown under N2-fixing conditions with and without Mo supply through an LC-MS/MS and label-free quantification analysis to address this gap. Protein abundances revealed overrepresented processes related to anaerobiosis growth adaption, Fe-S cluster biosynthesis, ammonia assimilation, electron transfer, and sporulation under N2-fixing conditions compared to non-fixing control. Under Mo limitation, the Fe-only nitrogenase components were overrepresented together with the Mo-transporter system, while the dinitrogenase component (NifDK) of Monitrogenase was underrepresented. The dinitrogenase reductase component (NifH) and accessory proteins encoded by the nif operon had no significant differential expression, suggesting post-transcriptional regulation of nif gene products in this strain. Overall, this was the first comprehensive proteomic analysis of a diazotrophic strain from the Paenibacillaceae family, and it provided insights related to alternative N2-fixation by Fe-only nitrogenase. SIGNIFICANCE: In this work, we try to understand how the alternative nitrogen fixation system, presented by some diazotrophic bacteria, works. For this, we used the SBR5 lineage of P. sonchi, which presents the alternative system in which the nitrogenase cofactor is composed only of iron. In addition, we tried to unravel the proteome of this strain in different situations of nitrogen fixation, since, for Gram-positive bacteria, these systems are little known. The results achieved, through LC-MS/MS and label-free quantitative analysis, showed an overrepresentation of proteins related to different processes involved with growth under stressful conditions in situations of nitrogen deficiency, in addition to suggesting that some encoded proteins by the nif operon may be regulated at post-transcriptional levels. Our findings represent important steps toward the elucidation of nitrogen fixation systems in Gram-positive diazotrophic bacteria.
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Fixação de Nitrogênio , Paenibacillus , Proteoma/metabolismo , Proteômica , Cromatografia Líquida , Espectrometria de Massas em Tandem , Nitrogenase/metabolismo , Paenibacillus/genética , Paenibacillus/metabolismo , Molibdênio/metabolismo , Ferro/metabolismo , Nitrogênio/metabolismoRESUMO
In 2015, >50 million cubic meters of Fe mining tailings were released into the Doce River basin from the Fundão dam, raising the question of its consequences on the affected ecosystems. This study aimed to establish a mineralogical-(geo)chemical association of potentially toxic elements (PTEs) from Fe mining tailings from the Fundão dam, collected seven days after the failure, through a multidisciplinary approach combining assessment of the risk to human health, environmental geochemistry, and mineralogy. Thus, eleven tailings samples were collected with the support of the Brazilian Military Police Fire Department. Granulometry, magnetic measurements, optical microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and sequential chemical extraction of PTEs analyses were performed. Contamination indexes, assessment of risk to human health, and Pearson correlation were calculated using the results of sequential chemical extraction of PTEs. The predominance of goethite in Fe oxyhydroxide concentrates from the mud indicates that the major source of hematite may not be from tailings, but from pre-existing soils and sediments, and/or preferential dissolution of hematite in deep flooded zones of the tailings column of the Fundão dam. Moreover, the high correlation of most carcinogenic PTEs with their crystallographic variables indicates that goethite is the primary source of contaminants. Goethites from Fe mining tailings showed high specific surface area and Al-substitution, and due to their greater stability and reactivity, the impacts on PTE sorption phenomena and bioavailability may be maintained for long periods. However, their lower dissolution rate, and the consequent release of heavy metals would promote greater resilience for affected ecosystems, preventing significant PTE inputs under periodic reduction conditions. More specific studies, involving the crystallographic characteristics of Fe oxyhydroxides should be developed since they may provide another critical component of this set of complex and dynamic variables that interfere with the bioavailability of metals in ecosystems.
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Compostos Férricos , Compostos de Ferro , Metais Pesados , Minerais , Poluentes Químicos da Água , Humanos , Ecossistema , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Metais Pesados/análise , Brasil , Rios/químicaRESUMO
Resumo Este estudo teve como objetivo determinar o efeito da adição de nanopartículas de selênio (SeNPs) ao agregado de trióxido mineral (MTA HP) em relação ao potencial alcalinizante. Além disso, examinou o material do conjunto após a incorporação de SeNPs usando a microscopia eletrônica de varredura de emissão de campo com análise de raios X por dispersão de energia (FE-SEM/EDX) para caracterizar a composição elementar e as alterações morfológicas resultantes da integração de SeNPs. As amostras de cimento, antes e depois da incorporação de SeNPs, foram examinadas usando FE-SEM/EDX. O nível de pH também foi medido com um pH-metro previamente calibrado com soluções de pH conhecido, para avaliar a atividade alcalinizante da substância integrada em diferentes concentrações de nanopartículas: Grupo 1 (controle): 0% p/p de SeNPs, Grupo 2: 0,5% p/p de SeNPs, Grupo 3: 1% p/p de SeNPs, Grupo 4: 1,5% p/p de SeNPs e Grupo 5: 2% p/p de SeNPs após 1, 7, 14 e 30 dias em água distal. Os dados foram analisados por ANOVA unidirecional e testes de Tukey (P≤0,05). De acordo com o FE-SEM/EDX, as características morfológicas indicam que as SeNPs foram dispersas e integradas com sucesso na matriz de reparo do MTA. A análise de EDX valida a presença de selênio, confirmando a integração bem-sucedida. Os resultados confirmaram que o MTAHP apresentou alto nível de pH com uma redução perceptível na atividade alcalinizante com cada concentração incorporada de (SeNPs) que diferiu significativamente do grupo de controle em vários períodos de tempo (P≤ 0,05). Consequentemente, os resultados indicam que a adição de SeNPs ao MTA HP tem um impacto notável sobre o pH da solução de armazenamento, levando a uma redução significativa nos valores de pH para todas as concentrações e períodos de tempo quando comparados ao grupo de controle. A ação alcalinizante do MTA HP é altamente afetada pelas SeNPs incorporadas, tornando-o mais adequado para aplicação no tecido pulpar. Este estudo contribui para a nossa compreensão das alterações morfológicas e da composição elementar do MTA HP incorporado com SeNPs, aprimorando suas possíveis aplicações na regeneração dentária e tecidual.
Abstract This study aimed to determine the effect of adding selenium nanoparticles (SeNPs) to mineral trioxide aggregate (MTA HP) concerning alkalinizing potential. Additionally, it examined the set material after SeNPs incorporation using Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray analysis (FE-SEM/EDX) for characterizing the elemental composition and morphological alterations resulting from the integration of SeNPs. Cement samples, both before and after SeNPs incorporation, were examined using FE-SEM/EDX. The pH level was also measured with a pH-meter previously calibrated with solutions of known pH, to evaluate the alkalinizing activity of the integrated substance at different concentrations of nanoparticles: Group 1 (control): 0% w/w SeNPs, Group 2: 0.5% w/w SeNPs, Group 3: 1% w/w SeNPs, Group 4: 1.5% w/w SeNPs and Group 5: 2% w/w SeNPs after 1, 7, 14, and 30 days in distal water. The data were analyzed by one-way ANOVA and Tukey tests (P≤0.05). According to FE-SEM/EDX, the morphological characteristics indicate that SeNPs were successfully dispersed and integrated into the MTA repair matrix. EDX examination validates the presence of Selenium, confirming successful integration. The findings confirmed that the MTAHP showed a high pH level with a discernible reduction in the alkalinizing activity with each incorporated concentration of (SeNPs) that significantly differed from the control group across various periods at (P≤ 0.05). Consequently, the findings indicate that the addition of SeNPs to MTA HP has a notable impact on the pH of the storage solution, leading to a significant decrease in pH values for all concentrations and periods when compared to the control group. The alkalinizing action of MTA HP is highly affected by the incorporated SeNPs, making it more suitable for application in pulpal tissue. This study contributes to our understanding of the morphological alterations and elemental composition of SeNP-incorporated MTA HP, enhancing its potential applications in dental and tissue regeneration.
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RESUMO Por meio da antropologia da saúde, podemos compreender o terreiro de umbanda como parte de um sistema popular de cuidado. Este estudo teve por objetivo investigar as concepções de saúde e doença produzidas por zeladores de terreiro de umbanda. Participaram dez zeladores de terreiro da cidade de Uberaba (MG/Brasil), sendo três mulheres e sete homens, com idades entre 40 e 76 anos. O tempo médio de atuação como dirigente foi de 18,4 anos, variando de cinco a 43 anos. Os terreiros chefiados por esses participantes atendem entre 15 e 280 pessoas por dia de funcionamento. Pela análise das entrevistas, destaca-se que o cuidado em saúde oferecido pelos zeladores ultrapassa os limites rituais, nas cerimônias públicas, sendo prestado de modo contínuo nos terreiros. As posturas assumidas pelos entrevistados envolvem ações de escuta, acolhimento e proximidade física no momento da urgência. Pelas narrativas, pode-se concluir que o zelar, no sentido de gerenciar o espaço do terreiro, espiritual e materialmente, não pode ser dissociado do cuidar, significando os zeladores como importantes agentes populares de saúde.
RESUMEN A través de la antropología de la salud podemos entender el terreiro de umbanda como parte de un sistema de atención popular. Este estudio tuvo como objetivo investigar las concepciones de salud y enfermedad producidas por los cuidadores del terreiro de umbanda. Participaron diez cuidadores de terreiro de la ciudad de Uberaba (MG/Brasil), tres mujeres y siete hombres, con edades comprendidas entre 40 y 76 años. El tiempo promedio como gerente fue de 18.4 años, que van de cinco a 43 años. Los terreiros encabezados por estos participantes atienden entre 15 y 280 personas por día de operación. Del análisis de las entrevistas, se destaca que la atención médica ofrecida por los cuidadores va más allá de los límites rituales, en ceremonias públicas, que se brindan continuamente en los terreiros. Las actitudes asumidas por los entrevistados implican escuchar, acoger y proximidad física en el momento de urgencia. A través de las narrativas, se puede concluir que el cuidado, en el sentido de administrar el espacio del terreiro, espiritual y materialmente, no se puede disociar del cuidado, lo que significa que los cuidadores son importantes agentes de salud populares.
ABSTRACT Through health anthropology we can understand the umbanda terreiro (specific place for the religious ritual) as part of a popular system of care. This study aimed to investigate the conceptions of health and illness produced by saint keepers of umbanda terreiro. Ten leaders of the terreiros in the city of Uberaba (MG/Brazil) participated, being three women and seven men, between 40 and 76 years old. The average time of performance as a manager was 18.4 years, ranging from 5 to 43 years. The terreiros led by these participants attend between 15 and 280 people working day. The health care offered by saint keepers exceeds ritual limits in public ceremonies and is provided on a continuous basis in the terreiros. The postures assumed by the interviewees involve actions of listening, welcoming and physical proximity at the moment of urgency. From the narratives, it can be concluded that care, in the sense of managing the space of the terreiro, both spiritually and materially, can not be dissociated from caring, meaning saint keepers as important popular health.
Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Terapêutica , Saúde Mental/ética , Cura pela Fé/ética , Autocuidado/psicologia , Comportamento Ritualístico , Emoções/ética , Acolhimento , Etnopsicologia/ética , Antropologia CulturalRESUMO
Undoped and Fe-doped NiO nanoparticles were successfully synthesized using a lyophilization method and systematically characterized through magnetization techniques over a wide temperature range, with varying intensity and frequency of the applied magnetic fields. The Ni1-xFexO nanoparticles can be described by a core-shell model, which reveals that Fe doping enhances exchange interactions in correlation with nanoparticle size reduction. The nanoparticles exhibit a superparamagnetic blocking transition, primarily attributed to their cores, at temperatures ranging from above room temperature to low temperatures, depending on the Fe-doping level and sample synthesis temperature. The nanoparticle shells also exhibit a transition at low temperatures, in this case to a cluster-glass-like state, caused by the dipolar magnetic interactions between the net magnetic moments of the clusters. Their freezing temperature shifts to higher temperatures as the Fe-doping level increases. The existence of an exchange bias interaction was observed, thus validating the core-shell model proposed.