RESUMO

Native stingless bees (Meliponini) from Brazil make (geo)propolis which is largely used in folk medicine, specially by indigenous and quilombos communities and beekeepers´ families but are progressively being recognized for their pharmacological activities. In this study, the ethanolic extracts of (geo)propolis (EEGs) from Melipona marginata, M. quadrifasciata, M. scutellaris, and Tetragonisca angustula were analysed by Flow injection analysis (FIA) and Ultra-high performance liquid chromatography (UHPLC) in a high resolution Orbitrap mass analyser (HRMS) to investigate and compare their chemical profile. Untargeted metabolomic approach based on UHPLC-HRMS experiments, and bioinformatic tools, allowed to annotate 59 compounds from diverse classes such as: flavonoids, phenolic compounds, sugars, terpenoids, and lipids. In addition, using multivariate tools and Flow injection- high resolution mass spectrometry (FIA-HRMS), it was possible to classify samples and identify marker ions related to the bee species or genus and to the geographical origin as a proof of concept.

RESUMO

Multi-ion-imprinted polymers (MIIPs) are materials with a wide range of applications mainly focused on environmental recovery, mining, technology, sensors, etc. MIIPs can incorporate ions such as heavy metals, transition metals, rare earth elements, radionuclides, and other types of ions. The chemical structures of MIIPs can be designed for different purposes and with certain morphologies, such as gels, crystals, or powders, and the surface area and porosity are also considered. All these properties provide the material with several desirable characteristics, like high selectivity, high specificity, adequate efficiency, good stability, the possibility of reusability, and strategy technology adaptation. In this review, we show the multitude of challenges of multi-ion imprinted polymer chemical synthesis based on the different and interesting methods reported previously.

RESUMO

Oleic acid-capped CdSe/ZnS quantum dots (QDs) were used to investigate their photoluminescence (PL) response to Hg2+ ions as a function of the surface properties of QDs. Three distinctly-size CdSe/ZnS QDs were obtained by varying the molar ratio of shell precursors, which were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier-Transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), absorption spectroscopy, and time-resolved fluorescence spectroscopy. Results revealed the obtention of zinc blende nanocrystals with sizes ranging from 2.7 to 3.2 nm (± 0.5) and ZnS thickness between 0.3 and 1.0 monolayer (ML). The variation of the [S]/[Zn] molar ratio introduced chemical species that act as traps, affecting the PL properties differently. Depending on the thickness of the shell and chemical speciation on surface, Hg2+ ions could induce quenching or enhancement of PL. Detection of mercury ions was evaluated in terms of Stern-Volmer equation, where the limit of detection (LOD) for the PL quenching system was 11.2 nM, while for the PL enhancing systems were 8.98 nM and 10.7 nM. Results demonstrate the performance of oleic acid-capped CdSe/ZnS QDs to detect Hg2+ and their capacity to turn the PL on/off depending on surface properties.

RESUMO

OBJECTIVES: The present study aimed to synthesize toothpastes containing Beta- TriCalcium Phosphate (ß-TCP) nanoparticles, functionalized with fluoride and tin, and test their ability to reduce erosive tooth wear (ETW). METHODS: Toothpastes were synthesized with the following active ingredients: 1100 ppm of fluoride (as sodium fluoride, F-), 3500 ppm of tin (as stannous chloride, Sn2+), and 800 ppm of ß-TCP (Sizes a - 20 nm; and b - 100 nm). Enamel specimens were randomly assigned into the following groups (n = 10): 1. Commercial toothpaste; 2. Placebo; 3 F-; 4. F- + ß-TCPa; 5. F- + ß-TCPb; 6. F- + Sn2+; 7. F- + Sn2+ + ß-TCPa and 8. F- + Sn2+ + ß-TCPb. Specimens were subjected to erosion-abrasion cycling. Surface loss (in µm) was measured by optical profilometry. Toothpastes pH and available F- were also assessed. RESULTS: Brushing with placebo toothpaste resulted in higher surface loss than brushing with F- (p = 0.005) and F- + ß-TCPb (p = 0.007); however, there was no difference between F- and F- + ß-TCPb (p = 1.00). Commercial toothpaste showed no difference from Placebo (p = 0.279). The groups F-, F- + ß-TCPa, F- + ß-TCPb, F- + Sn2+, F- + Sn2+ + ß-TCPa and F- + Sn2+ + ß-TCPb were not different from the commercial toothpaste (p > 0.05). Overall, the addition of ß-TCP reduced the amount of available fluoride in the experimental toothpastes. The pH of toothpastes ranged from 4.97 to 6.49. CONCLUSIONS: Although toothpaste containing ß-TCP nanoparticles protected enamel against dental erosion-abrasion, this effect was not superior to the standard fluoride toothpaste (commercial). In addition, the functionalization of ß-TCP nanoparticles with fluoride and tin did not enhance their protective effect. CLINICAL SIGNIFICANCE: Although ß-TCP nanoparticles have some potential to control Erosive Tooth Wear, their incorporation into an experimental toothpaste appears to have a protective effect that is similar to a commercial fluoride toothpaste.

Assuntos

Fosfatos de Cálcio , Esmalte Dentário , Nanopartículas , Erosão Dentária , Cremes Dentais , Fosfatos de Cálcio/química , Fosfatos de Cálcio/uso terapêutico , Cremes Dentais/química , Cremes Dentais/uso terapêutico , Erosão Dentária/prevenção & controle , Nanopartículas/química , Esmalte Dentário/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Compostos de Estanho/uso terapêutico , Compostos de Estanho/química , Fluoreto de Sódio/uso terapêutico , Fluoreto de Sódio/química , Animais , Fluoretos/uso terapêutico , Estanho/química , Abrasão Dentária/prevenção & controle , Bovinos , Teste de Materiais , Propriedades de Superfície , Distribuição Aleatória , Escovação Dentária , Humanos

RESUMO

We have investigated the gas-phase fragmentation reactions of 11 synthetic 4-aryl-3,4-dihydrocoumarins by electrospray ionization tandem mass spectrometry (ESI-MS/MS) on a quadrupole-time-of flight (Q-TOF) hybrid mass spectrometer. We have also estimated thermochemical data for the protonated coumarins (precursor ion A) and product ion structures by computational chemistry at a B3LYP level of theory to establish the ion structures and to rationalize the fragmentation pathways. The most abundant ions in the product ion spectra of coumarins 1-11 resulted from C8H8O2, CO2, C4H4O3, C8H10O3, C8H8O2, and CH3OH eliminations through retro-Diels-Alder (RDA) reactions, remote hydrogen rearrangements (ß-eliminations), and ß-lactone ring contraction. Although the investigated coumarins shared most of the fragmentation pathways, formation of a benzylic product ion and its corresponding tropylium ion was diagnostic of the substituents at ring C. The thermochemical data revealed that the nature and position of the substituents at ring C played a key role in the formation of this product ion and determined its relative intensity in the product ion spectrum. The results of this study contribute to knowledge of the gas-phase ion chemistry of this important class of organic compounds.

RESUMO

OBJECTIVES: To investigate the transdentinal effects of surface reaction-type pre-reacted glass-ionomer (S-PRG) fillers on odontoblast-like cells. METHODS: An eluate of S-PRG fillers was obtained by dissolving the particles in distilled water (1:1 m/v). Dentin discs with similar permeability were mounted into artificial pulp chambers and MDPC-23 cells were seeded on their pulpal surface. The occlusal surface was treated with (n = 10): ultrapure water (negative control - NC), hydrogen peroxide (positive control - PC), S-PRG eluate exposure for 1 min (S-PRG 1 min), or S-PRG filler eluate exposure for 30 min (S-PRG 30 min). After 24 h, cell viability (alamarBlue) and morphology (SEM) were evaluated. The extract obtained from transdentinal diffusion was applied to MDPC-23 pre-cultured in plates for another 24 h to evaluate viability (alamarBlue, 1, 3, and 7 days), gene expression of Col1a1, Alpl, Dspp, and Dmp1 (RT-qPCR, 1 and 7 days), and mineralization (Alizarin Red, 7 days). Data were analyzed with ANOVA (α = 5 %). RESULTS: While S-PRG 1 min did not differ from NC, S-PRG 30 min reduced 17.9 % viability of cells from discs. S-PRG treatments resulted in low cell detaching from dentin, and the remaining cells exhibited typical morphology or minor cytoplasmic contraction. S-PRG 30 min slightly increased cell viability (6 %) 1 day after contact with the extract. S-PRG treatments upregulated the expression of the investigated genes, especially after 1 day. S-PRG 30 min stimulated mineralization activity by 39.7 %. CONCLUSIONS: S-PRG filler eluate does not cause transdentinal cytotoxicity on odontoblast-like cells, and long-term exposure can stimulate their dentinogenic-related mineralization activity. SIGNIFICANCE: The transdentinal elution of ions from S-PRG fillers is not expected to be harmful to the dental pulp and may exert bioactive effects by inducing dentin matrix deposition through the metabolism of underlying odontoblasts.

Assuntos

Sobrevivência Celular , Dentina , Odontoblastos , Odontoblastos/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dentina/efeitos dos fármacos , Cimentos de Ionômeros de Vidro/farmacologia , Cimentos de Ionômeros de Vidro/química , Cimentos de Ionômeros de Vidro/toxicidade , Animais , Microscopia Eletrônica de Varredura , Teste de Materiais , Propriedades de Superfície , Camundongos , Células Cultivadas , Expressão Gênica/efeitos dos fármacos , Resinas Acrílicas , Dióxido de Silício

RESUMO

Water contamination represents a significant ecological impact with global consequences, contributing to water scarcity worldwide. The presence of several pollutants, including heavy metals, pharmaceuticals, pesticides, and pathogens, in water resources underscores a pressing global concern, prompting the European Union (EU) to establish a Water Watch List to monitor the level of these substances. Nowadays, the standard methods used to detect and quantify these contaminants are mainly liquid or gas chromatography coupled with mass spectrometry (LC/GC-MS). While these methodologies offer precision and accuracy, they require expensive equipment and experienced technicians, and cannot be used on the field. In this context, chalcogenide quantum dots (QDs)-based sensors have emerged as promising, user-friendly, practical, and portable tools for environmental monitoring. QDs are semiconductor nanocrystals that possess excellent properties, and have demonstrated versatility across various sensor types, such as fluorescent, electrochemical, plasmonic, and colorimetric ones. This review summarizes recent advances (2019-2023) in the use of chalcogenide QDs for environmental sensing, highlighting the development of sensors capable of detect efficiently heavy metals, anions, pharmaceuticals, pesticides, endocrine disrupting compounds, organic dyes, toxic gases, nitroaromatics, and pathogens.

RESUMO

Histoplasma capsulatum causes a fungal respiratory disease. Some studies suggest that the fungus requires zinc to consolidate the infection. This study aimed to investigate the influence of zinc and the metal chelator TPEN on the growth of Histoplasma in planktonic and biofilm forms. The results showed that zinc increased the metabolic activity, cell density, and cell viability of planktonic growth. Similarly, there was an increase in biofilm metabolic activity but no increase in biomass or extracellular matrix production. N'-N,N,N,N-tetrakis-2-pyridylmethylethane-1,2 diamine (TPEN) dramatically reduced the same parameters in the planktonic form and resulted in a decrease in metabolic activity, biomass, and extracellular matrix production for the biofilm form. Therefore, the unprecedented observations in this study highlight the importance of zinc ions for the growth, development, and proliferation of H. capsulatum cells and provide new insights into the role of metal ions for biofilm formation in the dimorphic fungus Histoplasma, which could be a potential therapeutic strategy.

RESUMO

This study was designed to assess the concentrations of nine water-soluble ions in PM10 mass at two sites of an open-pit coal mine and to analyze the correlation and variation of the spatial distribution of sulfate ions with the PM10 sulfate aerosol optical depth at 550 nm (suaod550) in two (North and South) stations of the study area. The daily average of PM10 concentrations ranged from 20.48 to 53.10 µg/m3 and thus did not exceed the daily average maximum permissible level of PM10 (100 µg/m3) established in the Colombia standard at any station. The concentrations of nine water-soluble ions in PM10 (Cl-, NO3-, PO43-, SO42- Na+, NH4+, K+, Mg2+, and Ca2+) were determined. The ions under analysis, SO42-, Na+, and NH4+ had the highest concentrations. Combined, they accounted for 75% of the mass of water-soluble ions in a total of 210 samples. The SO42- concentrations in PM10 significantly correlated with suaod550 (r ranging from 0.57 to 0.66), emphasizing the strong effect of suaod550 from Venezuela (Lake Maracaibo) on central and northern Colombia. These results demonstrate that the effects of local sulfate emissions near monitoring sites can be predicted and assessed using satellite data.

RESUMO

The work investigates the potential of peanut shells, an abundant agro-industrial waste, to serve as an adsorbent precursor for the effective and simple treatment of effluents loaded with cadmium and nickel ions. Among the adsorbents prepared, carbonized peanut shell (CCarb), due to its higher adsorption capacity, proved to be the most effective compared to carbonized and activated peanut shell (CATQ). The carbonization process led to structural changes, which resulted in an increase in surface area (around 6 times more in CATQ) and pore volume (around 3 times more in CATQ). Even so, the amount of H+ acid sites due to acid activation produced unfavorable effects for adsorption. Hydroxyl, carboxyl and carbonyl groups were identified on the adsorbent surface which presented favorable charges for metal adsorption. This improvement propels the carbonized variant to the forefront, demonstrating the highest adsorption capacity and reaching equilibrium in less than 90 and 60 min for cadmium and nickel ions, respectively. In both monocomponent and bicomponent systems concentrations greater than 40 ppm signify an increase in adsorption capacity for Ni2+. The experimental data best fit the Freundlich model, showing maximum adsorption capacities of 17.04 mg g-1 for cadmium and 31.28 mg g-1 for nickel. Despite the antagonistic effect observed in the bicomponent system, this study concludes by underlining the promise of activated carbon from peanut shells to harmonize technical and environmental concerns.

Assuntos

Níquel , Poluentes Químicos da Água , Cádmio , Arachis , Adsorção , Bismuto , Íons , Cinética , Poluentes Químicos da Água/análise , Concentração de Íons de Hidrogênio

RESUMO

Introdução: mapear os estudos que mensuraram o potencial Hidrogeniônico (pH) da região vulvar no ciclo vital da mulher. Métodos: revisão de escopo conforme recomendações do Manual for Evidence Synthesis do Joanna Briggs Institute (JBI), nas bases SCOPUS, Web of Science, Academic Search Premier, PubMed, Bielefeld Academic Search Engine e Google Acadêmico em janeiro de 2022. Foram incluídos estudos publicados em português, espanhol, francês e inglês, sem limite temporal. Resultados: dos 954 documentos recuperados, 13 foram selecionados. Apurou- se que os estudos utilizaram diferentes procedimentos para as medições quanto aos equipamentos, ambiente e preparo das participantes. A média de idade apresentada pela população feminina estudada variou entre 31 e 43 anos. Os locais de medição vulvar foram os grandes e pequenos lábios, dobra interlabial e períneo. O menor valor do pH aferido foi 4,6 e o maior 6,3. Conclusões: constatou-se baixa produção de estudos acerca do pH vulvar e ênfase das pesquisas na população de mulheres adultas. A diversidade de procedimentos e locais de aferição encontrados não permite afirmações seguras sobre uma faixa de valor de pH da superfície da pele vulvar.

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Introduction: to map the studies that measured the Potential of Hydrogen (pH) of the vulvar region in women's life cycle. Methods: scoping review according to recommendations from the Joanna Briggs Institute (JBI) Manual for Evidence Synthesis in the SCOPUS, Web of Science, Academic Search Premier, PubMed, Bielefeld Academic Search Engine and Google Scholar databases in January 2022. Studies published in Portuguese, Spanish, French, and English, without time limit, were included. Results: of the 954 documents retrieved, 13 were selected. Different measurement procedures in relation to equipment, environment and preparation of participants were used in the studies. The average age of the female population ranged between 31 and 43 years. The vulvar measurement sites were the labia majora and minora, interlabial sulci and perineum. The lowest pH value measured was 4.6 and the highest was 6.3. Conclusions: there was a low production of studies on vulvar pH and an emphasis of studies on the population of adult women. The diversity of procedures and measurement sites found does not allow for safe statements about a range of pH values on the surface of the vulvar skin.

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Introducción: mapear los estudios que midieron el Potencial de Hidrógeno (pH) de la región vulvar en el ciclo vital de las mujeres. Métodos: revisión del alcance según las recomendaciones del Manual for Evidence Synthesis del Joanna Briggs Institute (JBI), en las bases de datos SCOPUS, Web of Science, Academic Search Premier, PubMed, Bielefeld Academic Search Engine y Google Scholar en enero de 2022. Se incluyeron estudios publicados. en portugués, español, francés e inglés, sin límite de tiempo. Resultados: de los 954 documentos recuperados, se seleccionaron 13. En los estudios se utilizaron diferentes procedimientos de medición en relación con el equipo, el entorno y la preparación de los participantes. La edad media de la población femenina osciló entre 31 y 43 años. Los sitios de medición vulvar fueron los labios mayores y menores, el pliegue interlabial y el perineo. El valor de pH más bajo medido fue 4,6 y el más alto fue 6,3. Conclusiones: hubo una baja producción de estudios sobre pH vulvar y un énfasis de estudios en población de mujeres adultas. La diversidad de procedimientos y sitios de medición encontrados no permite realizar afirmaciones seguras sobre un rango de valores de pH en la superficie de la piel vulvar.

Assuntos

Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Vulva , Saúde da Mulher , Higiene da Pele , Concentração de Íons de Hidrogênio

RESUMO

Hemicellulose is widely available in nature, is a sustainable resource and has a wide range of applications. Among them, adsorption stands out for the removal of potentially toxic ions. Thus, in the study, the adsorption of Cd2+, Pb2+ and Hg2+ ions in two hemicellulose matrices were elucidated through computational simulations using density functional theory. Molecular electrostatic potential and frontier molecular orbitals demonstrated whether the interactions could happen. Four interaction complexes were highlighted due to the interaction energy criteria, ΔEBind, ΔH and ΔG < 0.00 kcal mol-1, that is: Hm1… Pb (1); Hm2… Pb (3); Hm2…Cd (4) and Hm2…Hg (4) and the results show that they occur through physisorption. In structural parameter studies, interaction distances smaller than 3000 Å were identified, which ranged from 2.253 Å to 2.972 Å. From the analysis of the topological parameters of QTAIM, it was possible to characterize the intensities of the interactions, as well as their nature, which were partially covalent or electrostatic in nature. Finally, based on the theoretical results, it can be affirmed that the hemicellulose can interact with Cd2+, Pb2+ and Hg2+ ions, evidencing that this study can support further experimental essays to remove contaminants from effluents.

Assuntos

Mercúrio , Polissacarídeos , Poluentes Químicos da Água , Cádmio/química , Chumbo , Adsorção , Termodinâmica , Íons , Modelos Teóricos , Poluentes Químicos da Água/análise

RESUMO

Objective: The objective of this study was to evaluate the impact of daily mouthwash rinsing protocols recommended against SARS-CoV-2 on metal ions discharged from fixed orthodontic appliances, specifically Nickel (Ni) and Chromium (Cr). Material and Methods: Total of 400 hemi-arch fixed appliances were segregated into two groups, namely Nickel Titanium (NiTi) and Stainless Steel (SS), based on the type of archwire employed. Each set was submerged in 2% povidone-iodine, 1% hydrogen peroxide, 0.2% chlorhexidine and cetylpyridinium chloride mouthwashes. Distilled water was used for comparative measurements of the ions released as a control group (n=10/group). They were incubated for four periods at 37°C (one hour, twenty-four hours, one, and 3 weeks). Nil and Cr ions released from the fixed appliance were evaluated by atomic absorption spectroscopy. The data were analyzed by the Kruskal-Wallis test and paired comparison analysis. Results: The worst levels of Ni and Cr liberated from the SS group observed in povidone-iodine mouthwash at 1.173 and 1.701 ppm, respectively, while the chlorhexidine mouthwash released accepted level of Ni and Cr at 0.033 and 0.056 ppm, respectively. The NiTi group displayed the appalling ions released of Ni and Cr in povidone-iodine mouthwash at 1.87 and 2.4 ppm, respectively. Whereas the released levels of Ni and Cr ions from the chlorhexidine group and cetylpyridinium chloride were 0.048 and 0.127 ppm, respectively, with significant differences between the tested groups and intervals. Conclusion: Chlorhexidine and Cetylpyridinium chloride mouthwashes were the appropriate options for orthodontic patients to minimized ions released according to this study protocol.(AU)

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Objetivo: O objetivo deste estudo é avaliar o impacto dos protocolos diários de enxaguatório bucal recomendados contra SARS-CoV-2 em íons metálicos liberados de aparelhos ortodônticos fixos, especificamente Níquel (Ni) e Cromo (Cr). Material e Métodos: Um total de 400 aparelhos fixos de hemiarcada foram segregados em dois grupos, Níquel Titânio (NiTi) e Aço Inoxidável (SS), com base no tipo de fio utilizado. Cada conjunto foi submerso em enxaguantes bucais com iodopovidona a 2%, peróxido de hidrogênio a 1%, clorexidina a 0,2% e cloreto de cetilpiridínio. Água destilada foi utilizada para medições comparativas dos íons liberados como grupo controle (n=10/grupo). Eles foram incubados por cinco períodos a 37°C (uma hora, vinte e quatro horas, uma e 3 semanas). Os íons Nil e Cr liberados do aparelho fixo foram avaliados por espectroscopia de absorção atômica. Os dados foram analisados pelo teste de Kruskal-Wallis e análise de comparação pareada. Resultados:Os piores níveis de Ni e Cr liberados no grupo SS foram observados no enxaguatório bucal com iodopovidona em 1,173 e 1,701 ppm, respectivamente, enquanto o enxaguatório bucal com clorexidina liberou níveis aceitos de Ni e Cr em 0,033 e 0,056 ppm, respectivamente. O grupo NiTi exibiu os terríveis íons liberados de Ni e Cr no enxaguatório bucal com iodopovidona a 1,87 e 2,4 ppm, respectivamente. Já os níveis liberados de íons Ni e Cr do grupo clorexidina e cloreto de cetilpiridínio foram 0,048 e 0,127 ppm, respectivamente, com diferenças significativas entre os grupos e intervalos testados. Conclusão: Enxaguatórios bucais com clorexidina e cloreto de cetilpiridínio foram as opções adequadas para pacientes ortodônticos para minimizar a liberação de íons de acordo com o protocolo deste estudo(AU)

Assuntos

Organização Mundial da Saúde , SARS-CoV-2 , Antissépticos Bucais

RESUMO

This study introduces a novel method for producing Ag nanoclusters (NCs) within GeO2-PbO glasses doped with Tm3+ ions. Sample preparation involved the melt-quenching method, employing adequate heat treatment to facilitate Ag NC formation. Absorption spectroscopy confirmed trivalent rare-earth ion incorporation. Ag NC identification and the amorphous structure were observed using transmission electron microscopy. A tunable visible emission from blue to the yellow region was observed. The energy transfer mechanism from Ag NCs to Tm3+ ions was demonstrated by enhanced 800 nm emission under 380 and 400 nm excitations, mainly for samples with a higher concentration of Ag NCs; moreover, the long lifetime decrease of Ag NCs at 600 nm (excited at 380 and 400 nm) and the lifetime increase of Tm3+ ions at 800 nm (excitation of 405 nm) corroborated the energy transfer between those species. Therefore, we attribute this energy transfer mechanism to the decay processes from S1→T1 and T1→S0 levels of Ag NCs to the 3H4 level of Tm3+ ions serving as the primary path of energy transfer in this system. GeO2-PbO glasses demonstrated potential as materials to host Ag NCs with applications for photonics as solar cell coatings, wideband light sources, and continuous-wave tunable lasers in the visible spectrum, among others.

RESUMO

This study reports the use of an inorganic corrosion inhibitor to mitigate dissolved CO2-induced corrosion. Using electrochemical techniques (polarization curves, open circuit potential, polarization resistance, and electrochemical impedance), the effect of adding Nd3+ ions on the corrosion resistance of X52 steel immersed in CO2-saturated brine at 20 °C and 60 °C was evaluated. The polarization curves showed that the Icorr values tend to decrease with increasing Nd3+ ion concentration, up to the optimal inhibition concentration, and that the corrosion potential increases at nobler values. Open circuit potential measurements showed a large increase in potential values immediately after the addition of the Nd3+ ions. Similarly, polarization resistance measurements showed similar trends. It was observed that regardless of temperature, Nd3+ ions can reduce the corrosion rate by more than 97% at doses as low as 0.001 M. Electrochemical impedance measurements confirmed the formation of a protective layer on the steel surface, which caused an increase in the magnitude of the impedance module and phase angle, which indicates an increase in the resistance to charge transfer and capacitive properties of the metallic surface. The characterization of the metallic surface showed that the protective layer was formed by Nd carbonates, whose formation was due to a CO2 capture process.

RESUMO

Abstract This study compared the pH and calcium ion release of calcium silicate- (Bio-C Temp) and calcium hydroxide-based (Ultracal XS) medications. Intracanal remnants of both medications were also evaluated using SEM-EDS after the removal protocol. Thirty-five bovine teeth were prepared. Fifteen were filled with Bio-C Temp and 15 with Ultracal XS. Five remained without intracanal medication (control group). Five samples from each experimental time (i.e.. 24, 72, and 168 hours) were used to measure pH and calcium ions release using a digital pH meter and microplate reader, respectively. Afterward, the peaks of the chemical elements composing both medications were analyzed in SEM-EDS. One-way ANOVA and Tukey's post hoc test analyzed the pH and calcium ion release data. Student's t-test compared the medications in each experimental time. SEM-EDS described the percentage of chemical elements in the samples. Bio-C Temp and Ultracal XS showed a significant pH increase from 24 to 168 hours (p<0.05). Ultracal XS showed a higher pH value at 24 hours than Bio-C Temp (p<0.05) but were similar at 72 and 168h (p > 0.05). Calcium ion release did not depend on the experimental period (p > 0.05). Bio-C Temp showed lower calcium ions release than Ultracal XS at 24 hours (p<0.05). SEM-EDS analyses showed the remains of both medications, but the concentration of Si, Al, and W ions was present only in the calcium silicate-based medication. Bio-C Temp presented alkaline pH and a satisfactory calcium ion release over the time. The remaining of both medications were present after the protocols for paste removal.

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Resumo Este estudo comparou o pH e a liberação de íons cálcio de medicações intracanais a à base de silicato de cálcio (Bio-C Temp) e à base de hidróxido de cálcio (Ultracal XS). Remanescentes de ambas as medicações também foram avaliados usando microscopia eletrônica de varredura e espectroscopia de dispersão de energia após o protocolo de remoção. Trinta e cinco dentes bovinos foram preparados. Quinze dentes foram preenchidos com Bio-C Temp e 15 com Ultracal XS. Cinco permaneceram sem medicação intracanal (grupo controle). Cinco amostras de cada tempo experimental (ou seja, 24, 72 e 168 horas) foram usadas para medir o pH e a liberação de íons de cálcio usando um medidor de pH digital e um leitor de microplacas, respectivamente. Em seguida, os picos dos elementos químicos que compõem os dois medicamentos foram analisados ​​em microscopia eletrônica de varredura e por espectroscopia de dispersão de energia. Os testes One-way ANOVA e post hoc de Tukey analisaram os dados de pH e liberação de íons cálcio. O teste t de Student comparou as medicações em cada tempo experimental. A microscopia eletrônica de varredura e a espectroscopia de dispersão de energia descreveu a porcentagem de elementos químicos nas amostras. O Bio-C Temp e o Ultracal XS mostraram um aumento significativo de pH de 24 a 168 horas (p<0,05). O Ultracal XS apresentou um valor de pH mais alto em 24 horas do que o Bio-C Temp (p<0,05), mas foi semelhante em 72 e 168h (p > 0,05). A liberação de íons cálcio não dependeu do período experimental (p> 0,05). O Bio-C Temp apresentou menor liberação de íons de cálcio do que Ultracal XS em 24 horas (p<0,05). As análises de microscopia eletrônica de varredura e espectroscopia de dispersão de energia mostraram remanescentes de ambas as medicações, mas a concentração de íons Si, Al e W estavam presentes apenas na medicação à base de silicato de cálcio. O Bio-C Temp apresentou pH alcalino e maior liberação de íons cálcio. Remanescentes de ambas as medicações estiveram presentes após os protocolos de remoção da pasta.

RESUMO

In this study, inert dry bioadsorbents prepared from corn cob residues (CCR), cocoa husk (CH), plantain peels (PP), and cassava peels (CP) were used as adsorbents of heavy metal ions (Pb2+ and Ni2+) in single-batch adsorption experiments from synthetic aqueous solutions. The physicochemical properties of the bioadsorbents and the adsorption mechanisms were evaluated using different experimental techniques. The results showed that electrostatic attraction, cation exchange, and surface complexation were the main mechanisms involved in the adsorption of metals onto the evaluated bioadsorbents. The percentage removal of Pb2+ and Ni2+ increased with higher adsorbent dosage, with Pb2+ exhibiting greater biosorption capacity than Ni2+. The bioadsorbents showed promising potential for adsorbing Pb2+ with monolayer adsorption capacities of 699.267, 568.794, 101.535, and 116.820 mg/g when using PP, CCR, CH, and CP, respectively. For Ni2+, Langmuir's parameter had values of 10.402, 26.984, 18.883, and 21.615, respectively, for PP, CCR, CH, and CP. Kinetics data fitted by the pseudo-second-order model revealed that the adsorption rate follows this order: CH > CP > CCR > PP for Pb2+, and CH > CCR > PP > CP for Ni2+. The adsorption mechanism was found to be controlled by ion exchange and precipitation. These findings suggest that the dry raw biomasses of corn cob residues, cocoa husk, cassava, and plantain peels can effectively remove lead and nickel, but further research is needed to explore their application in industrial-scale and continuous systems.

RESUMO

In this work, copper (II) ions were saturated and copper oxide nanoparticles (CuO NPs) were supported in natural zeolite from Chile; this was achieved by making the adsorbent material come into contact with a copper ion precursor solution and using mechanical agitation, respectively. The kinetic and physicochemical process of the adsorption of copper ions in the zeolite was studied, as well as the effect of the addition of CuO NPs on the antibacterial properties. The results showed that the saturation of copper (II) ions in the zeolite is an efficient process, obtaining a 27 g L-1 concentration of copper ions in a time of 30 min. The TEM images showed that a good dispersion of the CuO NPs was obtained via mechanical stirring. The material effectively inhibited the growth of Gram-negative and Gram-positive bacteria that have shown resistance to methicillin and carbapenem. Furthermore, the zeolite saturated with copper at the same concentration had a better bactericidal effect than the zeolite supported with CuO NPs. The results suggested that the ease of processing and low cost of copper (II) ion-saturated zeolitic material could potentially be used for dental biomedical applications, either directly or as a bactericidal additive for 3D printing filaments.

RESUMO

Pathophysiological conditions such as endothelial dysfunction and arterial stiffness, characterized by low nitric oxide bioavailability, deficient endothelium-dependent vasodilation and heart effort, predispose individuals to atherosclerotic lesions and cardiac events. Nitrate (NO3-), L-arginine, L-citrulline and potassium (K+) can mitigate arterial dysfunction and stiffness by intensifying NO bioavailability. Dietary compounds such as L-arginine, L-citrulline, NO3- and K+ exert vasoactive effects as demonstrated in clinical interventions by noninvasive flow-mediated vasodilation (FMD) and pulse-wave velocity (PWV) prognostic techniques. Daily L-arginine intakes ranging from 4.5 to 21 g lead to increased FMD and reduced PWV responses. Isolated L-citrulline intake of at least 5.6 g has a better effect compared to watermelon extract, which is only effective on endothelial function when supplemented for longer than 6 weeks and contains at least 6 g of L-citrulline. NO3- supplementation employing beetroot at doses greater than 370 mg promotes hemodynamic effects through the NO3--NO2-/NO pathway, a well-documented effect. A potassium intake of 1.5 g/day can restore endothelial function and arterial mobility, where decreased vascular tone takes place via ATPase pump/hyperpolarization and natriuresis, leading to muscle relaxation and NO release. These dietary interventions, alone or synergically, can ameliorate endothelial dysfunction and should be considered as adjuvant therapies in cardiovascular diseases.

Assuntos

Doenças Cardiovasculares , Rigidez Vascular , Humanos , Citrulina/farmacologia , Fatores de Risco , Vasodilatação , Fatores de Risco de Doenças Cardíacas , Arginina/farmacologia , Endotélio Vascular , Óxido Nítrico/farmacologia

RESUMO

In this work we report on the results of the total K-shell X-ray production cross sections of Ti, Cr, Ni and Zn induced by Cl4+ and Cl5+ ions with energies ranging from 4 MeV to 10 MeV. The experimental results were compared with Atomic Orbitals Coupled-Channels (CC) calculations based on the independent electron model. The experimental X-ray production cross sections vary from about 10-2 barns for Zn up to 102 barns for Ti. The results obtained for Ti indicate that the present CC calculations underestimate the experimental cross sections up to two orders of magnitude at 10 MeV chlorine bombarding energy. However, the discrepancy between CC calculations and experimental results decreases as both bombarding energy and the atomic number of the target species increase. The dependency of the experiment-theory agreement on the asymmetry and adiabaticity parameters α and η respectively is discussed.