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1.
PeerJ ; 12: e17237, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38699192

RESUMO

Background: Root perforation repair presents a significant challenge in dentistry due to inherent limitations of existing materials. This study explored the potential of a novel polydopamine-based composite as a root repair material by evaluating its sealing efficacy, radiopacity, and surface topography. Methods: Confocal microscopy assessed sealing ability, comparing the polydopamine-based composite to the gold standard, mineral trioxide aggregate (MTA). Radiopacity was evaluated using the aluminium step wedge technique conforming to ISO standards. Surface roughness analysis utilized atomic force microscopy (AFM), while field emission scanning electron microscopy (FESEM) visualized morphology. Results: The polydopamine-based composite exhibited significantly superior sealing efficacy compared to MTA (P < 0.001). Radiopacity reached 3 mm aluminium equivalent, exceeding minimum clinical requirements. AFM analysis revealed a smooth surface topography, and FESEM confirmed successful composite synthesis. Conclusion: This study demonstrates promising properties of the polydopamine-based composite for root perforation repair, including superior sealing efficacy, clinically relevant radiopacity, and smooth surface topography. Further investigation is warranted to assess its clinical viability and potential translation to endodontic practice.


Assuntos
Compostos de Alumínio , Compostos de Cálcio , Indóis , Óxidos , Polímeros , Materiais Restauradores do Canal Radicular , Silicatos , Propriedades de Superfície , Polímeros/química , Indóis/química , Silicatos/química , Compostos de Cálcio/química , Óxidos/química , Materiais Restauradores do Canal Radicular/química , Compostos de Alumínio/química , Humanos , Combinação de Medicamentos , Microscopia Eletrônica de Varredura , Microscopia de Força Atômica/métodos , Microscopia Confocal , Teste de Materiais , Raiz Dentária/lesões , Raiz Dentária/diagnóstico por imagem , Raiz Dentária/cirurgia
2.
Water Res ; 256: 121526, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38583333

RESUMO

The presence of Ag(I) and Pb(II) ions in wastewater poses a significant threat to human health in contemporary times. This study aims to explore the development of a novel and economical adsorbent by grafting MnO2 particles onto low-rank coal, providing an innovative solution for the remediation of water contaminated with silver and lead. The synthesized nanocomposites, referred to as MnO2-Coal, underwent thorough characterization using FTIR, XRD, BET, and SEM to highlight the feasibility of in-situ surface modification of coal with MnO2 nanoparticles. The adsorption of Ag(I) and Pb(II) from their respective aqueous solution onto MnO2-Coal was systematically investigated, with optimization of key parameters such as pH, temperature, initial concentration, contact time, ionic strength, and competing ions. Remarkably adsorption equilibrium was achieved within a 10 min, resulting in impressive removal rates of 80-90 % for both Ag(I) and Pb(II) at pH 6. The experimental data were evaluated using Langmuir, Freundlich, and Temkin isotherm models. The Langmuir isotherm model proved to be more accurate in representing the adsorption of Ag(I) and Pb(II) ions onto MnO2-Coal, exhibiting high regression coefficients (R2 = 0.99) and maximum adsorption capacities of 93.57 and 61.98 mg/g, along with partition coefficients of 4.53 and 71.92 L/g for Ag(I) and Pb(II), respectively, at 293 K. Kinetic assessments employing PFO, PSO, Elovich, and IPD models indicated that the PFO and PSO models were most suitable for adsorption mechanism of Pb(II) and Ag(I) on MnO2-Coal composites, respectively. Moreover, thermodynamic evaluation revealed the spontaneous and endothermic adsorption process for Ag(I), while exothermic behavior for adsorption of Pb(II). Importantly, this approach not only demonstrates cost-effectiveness but also environmental friendliness in treating heavy metal-contamination in water. The research suggests the potential of MnO2-Coal composites as efficient and sustainable adsorbents for water purification applications.


Assuntos
Chumbo , Compostos de Manganês , Óxidos , Prata , Águas Residuárias , Poluentes Químicos da Água , Prata/química , Chumbo/química , Águas Residuárias/química , Poluentes Químicos da Água/química , Adsorção , Compostos de Manganês/química , Óxidos/química , Carvão Mineral , Purificação da Água/métodos , Concentração de Íons de Hidrogênio , Cinética
3.
Free Radic Res ; 58(3): 194-216, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38563404

RESUMO

Microwave (MW) radiations are widely used in communications, radar and medical treatment and thus human exposure to MW radiations have increased tremendously, raising health concerns as MW has been implicated in induction of oxidative stress condition in our body. Few metallic nanoparticles (NPs) have been shown to mimic the activity of antioxidant enzymes and hence can be applied for the modulation of adverse effects caused by MW. Present study aimed to assess the biocompatibility of Bovine serum albumin (BSA) conjugated manganese dioxide nanoparticles (MNP*) and to counteract the impact of MW on the haematological system of male Wistar rats. Experiments were conducted in two sets. Set I involved biodistribution and antioxidant activity evaluation of MNP* at different doses. Results showed a dose-dependent increase in antioxidant potential and significant biodistribution in the liver, spleen, kidney, and testis, with no organ damage, indicating its biocompatibility. Experiment set II constituted the study of separate and combined effects of MW and MNP* on haematological parameters, oxidative status, and genotoxic study in the blood of rats. MW exposure significantly altered red blood cell count, hemoglobin, packed cell volume percentage, monocyte percentage, aspartate aminotransferase, Alanine aminotransferase and uric acid. MW also induced significant DNA damage in the blood. A significant increase in lipid peroxidation and a decrease in antioxidant enzyme superoxide dismutase was also observed in MW exposed group. However, these alterations were reduced significantly when MNP* was administered. Thus, MNP* showed biocompatibility and modulatory effects against MW-induced alterations in the haematological system of rats.


Assuntos
Compostos de Manganês , Micro-Ondas , Nanopartículas , Óxidos , Ratos Wistar , Soroalbumina Bovina , Animais , Masculino , Compostos de Manganês/química , Ratos , Soroalbumina Bovina/química , Óxidos/química , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Bovinos , Antioxidantes/farmacologia , Nanopartículas Metálicas/química
4.
Sci Total Environ ; 915: 170121, 2024 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-38232841

RESUMO

Manganese oxide (MnO2) is one of the most abundant metal oxides, and it is renowned for its ability to degrade various phenolic micropollutants. However, under MnO2-mediated transformation, BP-3 transforms into 12 different radical-coupled transformation products (TPs) out of 15 identified TPs. These radical-coupled TPs are reported with adverse environmental impacts. This study explored the effects of MnO2 on organic UV filter mixtures and different water constituents (i.e., bicarbonate ion (HCO3-), humic acid (HA) and halide ions) in terms of degradation efficiency and transformation chemistry. When a mixture of benzophenone-3 (BP-3) and avobenzone (AVO) underwent transformation by MnO2, hybrid radical-coupled TPs derived from both organic UV filters were generated. These hybrid radical-coupled TPs were evaluated by an in silico prediction tool and Vibrio fischeri bioluminescence inhibition assay (VFBIA). Results showed that these TPs were potentially toxic to aquatic organisms, even more so than their parent compounds. The higher the concentration of HCO3-, HA, chloride ion (Cl-) and bromide ion (Br-), the greater the reduction in the efficiencies of degrading BP-3 and AVO. Contrastingly, in the presence of iodide ion (I-), degradation efficiencies of BP-3 and AVO were enhanced; however, iodinated TPs and iodinated radical-coupled TPs were formed, with questionable toxicity. This study has revealed the environmental risks of hybrid radical-coupled TPs, iodinated TPs and iodinated radical-coupled TPs when the organic UV filters BP-3 and AVO are transformed by MnO2.


Assuntos
Óxidos , Poluentes Químicos da Água , Óxidos/química , Oxirredução , Compostos de Manganês/química , Água , Fenóis/química , Substâncias Húmicas , Poluentes Químicos da Água/análise
5.
Environ Pollut ; 339: 122736, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37838321

RESUMO

Recently, it has been reported that chlorine dioxide (ClO2) and (bi)sulfite/ClO2 showed excellent performance in micropollutant removal from water; however, the degradation mechanisms and application boundaries of the two system have not been identified. In this study, bisphenol A (BPA) was chosen as the target contaminant to give multiple comparisons of ClO2 and S(IV)/ClO2 process regarding the degradation performance of contaminant, generation of reactive species, transformation of products and toxicity variation. Both ClO2 and S(IV)/ClO2 can degrade BPA within 3 min. The BPA degradation mechanism was mainly based on direct oxidation in ClO2 process while it was attributed to radicals (especially SO4·-) generation in S(IV)/ClO2 process. Meanwhile, the effect of pH and coexisting substances (Cl-, Br-, HCO3- and HA) were evaluated. It was found that ClO2 preferred the neutral and alkaline condition and S(IV)/ClO2 preferred the acidic condition for BPA degradation. An unexpected speed-up of BPA degradation was observed in ClO2 process in the presence of Br-, HCO3- and HA. In addition, the intermediate products in BPA degradation were identified. Three exclusive products were found in ClO2 process, in which p-benzoquinone was considered to be the reason of the acute toxicity increase in ClO2 process.


Assuntos
Compostos Clorados , Poluentes Químicos da Água , Purificação da Água , Óxidos/toxicidade , Óxidos/química , Compostos Clorados/toxicidade , Compostos Clorados/química , Fenóis/toxicidade , Oxirredução , Cloro/química , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise
6.
Environ Sci Pollut Res Int ; 30(41): 93916-93933, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37518843

RESUMO

Photocatalytic degradation of pharmaceutical residues through natural solar radiation represents a green and economical treatment process. In this work, ultrasonically assisted hydrothermal synthesis of WO3-TiO2 nanocomposite was carried out at 140-150 °C for 5 h and calcinated at 600 °C. The structural and optical properties of the synthesized material were investigated using techniques like XRD, FESEM/EDX, HRTEM, BET surface area, UV-DRS optical analysis, and photocurrent response. The band gap of TiO2 was successfully reduced from 3.0 to 2.54 eV and thus making it effective under solar light. Complete degradation of paracetamol (50 ppm and natural pH of 6.5) was achieved in 3.5 h under natural sunlight at catalyst dose of 0.5 g/l. The extent of mineralization was evaluated by measuring the COD reduction. Based on the degradation products identified by GC-MS/LC-TOF-MS, the degradation process under natural solar-light could be interpreted to initiate through OH. radical species. The toxicity removal of the treated paracetamol solution under natural solar-light was evaluated by the seed germination test using Spinacia oleracea seeds and exhibited 66.70% seed germination, confirming the reduction in toxicity. The enhanced photocatalytic efficiency of the nanocomposite is attributed to the higher surface area, low rutile content, lower band gap, and incorporation of WO3, which led to an extended absorption range and a slower rate of electron-hole recombination. The technical insights presented in this research offer a feasible approach for utilizing natural solar light driven photocatalysis for wastewater treatment in an efficient and sustainable way. The proposed degradation pathway, and seed germination test (toxicity removal) of the treated paracetamol solution under natural sunlight, has not been previously evaluated.


Assuntos
Nanocompostos , Luz Solar , Óxidos/química , Acetaminofen , Tungstênio , Titânio/química , Catálise , Nanocompostos/química , Luz
7.
Water Sci Technol ; 87(11): 2840-2851, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37318927

RESUMO

Infectious diseases have risen dramatically as a result of the resistance of many common antibiotics. Nanotechnology provides a new avenue of investigation for the development of antimicrobial agents that effectively combat infection. The combined effects of metal-based nanoparticles (NPs) are known to have intense antibacterial activities. However, a comprehensive analysis of some NPs regarding these activities is still unavailable. This study uses the aqueous chemical growth method to synthesize Co3O4, CuO, NiO and ZnO NPs. The prepared materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. The antibacterial activities of NPs were tested against Gram-positive and Gram-negative bacteria using the microdilution method, such as the minimum inhibitory concentration (MIC) method. The best MIC value among all the metal oxide NPs was 0.63 against Staphylococcus epidermidis ATCC12228 through ZnO NPs. The other metal oxide NPs also showed satisfactory MIC values against different test bacteria. In addition, the biofilm inhibition and antiquorum sensing activities of NPs were also examined. The present study presents a novel approach for the relative analysis of metal-based NPs in antimicrobial studies, demonstrating their potential for bacteria removal from water and wastewater.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Óxido de Zinco , Antibacterianos/farmacologia , Antibacterianos/química , Óxido de Zinco/farmacologia , Óxido de Zinco/química , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Óxidos/química , Anti-Infecciosos/farmacologia , Nanopartículas Metálicas/química , Bactérias
8.
Chemosphere ; 337: 139064, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37321457

RESUMO

Outer ear infections (OEs) affect millions of people each year and are associated with significant medical costs.The usage of multiple antibiotics to treat ear contamination is a concern because it can have an environmental impact, especially on soil and water.The increased use of antibiotics has exposed bacterial ecosystems to high concentrations of antibiotic residues.Although there have been efforts to minimize the impact of antibiotics, adsorption methods have yielded better and more viable results, and carbon-based materials are effective for environmental remediation.Graphene oxide (GO) is a versatile material used in various applications such as nanocomposites, antibacterial agents, photocatalysis, electronics, and biomedicine.GO can act as an antibiotic carrier and affect the antibacterial efficacy of antibiotics.However, the processes responsible for the antibacterial activity of GO and antibiotics in treating ear infections are unknown.This study investigates the effect of GO on the antibacterial activity of tetracycline (TT) against Escherichia coli (E.coli)-negative bacteria.Artificial Neural Network-Genetic Algorithm (ANN-GA) was applied to analyze data on the effectiveness of different doses and combinations of graphene oxide and antibiotics in treating ear infections.This study could help identify the most effective treatment protocols and potentially reduce the risk of antibiotic resistance.The R-squared (R2) value, RMSE, and MSE all fall within the proper levels for fitting criteria, with R2 ≥ 0.97 (97%), RMSE ≤ 0.036064, and MSE ≤ 0.00199 (6% variance).The outcomes showed high antimicrobial activity, resulting in a 5-log decline of E.coli.In experiments, GO was shown to coat the bacteria, interfere with their cell membranes, and aid in the prevention of bacterial growth, although this effect was somewhat weaker for E.coli.The concentration and duration at which bare GO can kill E.coli are both important factors.The antibacterial activity of antibiotics can be either boosted or reduced by the presence of GO, depending on the GO's interaction with the antibiotic, the GO's contact with the microbe, and the sensitivity of the bacteria to the antibiotic.The antibacterial efficiency of the combination of GO and antibiotics varies depending on the specific antibiotic and microorganism being targeted.


Assuntos
Grafite , Nanopartículas Metálicas , Nanopartículas , Elementos de Transição , Humanos , Óxidos/farmacologia , Óxidos/química , Águas Residuárias , Análise Custo-Benefício , Ecossistema , Antibacterianos/farmacologia , Antibacterianos/química , Grafite/química , Bactérias , Inteligência Artificial , Nanopartículas Metálicas/química
9.
Biomater Adv ; 145: 213272, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36586204

RESUMO

A novel hybrid nanocomposite formed of carboxylated Nano Graphene Oxide (c-NGO), highly densely decorated by monodisperse citrate-coated Au nanoparticles (c-NGO/Au NPs), is synthesized and thoroughly characterized for photothermal applications. A systematic investigation of the role played by the synthetic parameters on the Au NPs decoration of the c-NGO platform is performed, comprehensively studying spectroscopic and morphological characteristics of the achieved nanostructures, thus elucidating their still not univocally explained synthesis mechanism. Remarkably, the Au NPs coating density of the c-NGO sheets is much higher than state-of-the-art systems with analogous composition prepared with different approaches, along with a higher NPs size dispersion. A novel theoretical approach for estimating the average number of NPs per sheet, combining DLS and TEM results, is developed. The assessment of the c-NGO/Au NPs photothermal activity is performed under continuous wave (CW) laser irradiation, at 532 nm and 800 nm, before and after functionalization with PEG-SH. c-NGO/Au NPs composite behaves as efficient photothermal agent, with a light into heat conversion ability higher than that of the single components. The c-NGO/Au NPs compatibility for photothermal therapy is assessed by in vitro cell viability tests, which show no significant effects of c-NGO/Au NPs, as neat and PEGylated, on cell metabolic activity under the investigated conditions. These results demonstrate the great potential held by the prepared hybrid nanocomposite for photothermal conversion technologies, indicating it as particularly promising platform for photothermal ablation of cancer cells.


Assuntos
Nanopartículas Metálicas , Óxidos , Óxidos/farmacologia , Óxidos/química , Ouro/farmacologia , Ouro/química , Linhagem Celular Tumoral , Nanopartículas Metálicas/uso terapêutico , Nanopartículas Metálicas/química , Lasers
10.
Artigo em Inglês | MEDLINE | ID: mdl-36554984

RESUMO

Fluoride concentrations in the groundwater continue to be a major cause for concern in Thailand, particularly in the country's north and west. The process of removing fluoride through adsorption has captured the attention of the abundance of ore in the mining industry. For the purpose of this investigation, the utilization of the adsorbent pyrolusite, which is a manganese mineral largely composed of MnO2, was a major component. Lab-scale experiments were conducted to investigate the efficacy of original pyrolusite ore (PA-1) and acid-modification PA (PA-2) created as low-cost adsorption materials for fluoride removal. The results of the adsorption rate in both PAs showed a fast rate of adsorption within 60 min of reaching equilibrium. According to the results of the adsorption capacity (qe) tests, PA that had been treated with an acid solution (PA-2) had the capacity to contain more fluoride (qe = 0.58 mg/g) than the PA that had been used initially (PA-1) (qe = 0.11 mg/g). According to the findings of an isotherm, primary adsorption behavior is determined by the effect that surface components and chemical composition have on porous materials. This is the first current study that provides a comparison between pyrolusite from Thailand's mining industry and basic modified pyrolusite regarding their ability to remove a fluoride contaminant in synthetic groundwater by an adsorption process. Such an approach will be able to be used in the future to protect the community from excessive fluoride concentrations in household and drinking water treatment technology.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Fluoretos , Óxidos/química , Compostos de Manganês/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Purificação da Água/métodos , Poluentes Químicos da Água/análise
11.
Bioelectrochemistry ; 147: 108177, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35752030

RESUMO

The present work describes an easy way to prepare a Chloroplast/PDA@WO3 biohybrid platform based on the deposition of chloroplasts on WO3 substrate previously modified with polydopamine (PDA) film as anchoring agent. The use of PDA as an immobilization matrix for chloroplasts, and also as an electron mediator under LED irradiation, resulted in enhanced photocurrents. The use of the chloroplasts amplified the photocurrent, when compared to the bare substrate (WO3). The best electrode performance was obtained using high intensity LED irradiation at 395 nm, for the electrode exposed for 10 min to 150 µg mL-1 of intact chloroplasts. Amperometric curves obtained by on/off cycles using an applied potential of +0.50 V, in PBS electrolyte (pH 7.0), showed that the presence of 0.2 × 10-3 mol L-1 of simazine caused an approximately 50% decrease of the photobiocurrent. Preliminary studies indicated that the synthesized platform based on intact chloroplasts is a good strategy for studying the behavior of photosynthetic entities, using an LED light-responsive WO3 semiconductor substrate. This work contributes to the understanding of photobiocatalysts that emerge as a new class of materials with sophisticated and intricate structures. These are promising materials with remarkably improved quantum efficiency with potential applications in photobioelectrocatalysis.


Assuntos
Óxidos , Tungstênio , Cloroplastos/metabolismo , Eletrodos , Óxidos/química , Fotossíntese , Tungstênio/química , Tungstênio/metabolismo
12.
Int J Mol Sci ; 22(11)2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34199667

RESUMO

Nanoparticles (NPs) with a high atomic number (Z) are promising radiosensitizers for cancer therapy. However, the dependence of their efficacy on irradiation conditions is still unclear. In the present work, 11 different metal and metal oxide NPs (from Cu (ZCu = 29) to Bi2O3 (ZBi = 83)) were studied in terms of their ability to enhance the absorbed dose in combination with 237 X-ray spectra generated at a 30-300 kVp voltage using various filtration systems and anode materials. Among the studied high-Z NP materials, gold was the absolute leader by a dose enhancement factor (DEF; up to 2.51), while HfO2 and Ta2O5 were the most versatile because of the largest high-DEF region in coordinates U (voltage) and Eeff (effective energy). Several impacts of the X-ray spectral composition have been noted, as follows: (1) there are radiation sources that correspond to extremely low DEFs for all of the studied NPs, (2) NPs with a lower Z in some cases can equal or overcome by the DEF value the high-Z NPs, and (3) the change in the X-ray spectrum caused by a beam passing through the matter can significantly affect the DEF. All of these findings indicate the important role of carefully planning radiation exposure in the presence of high-Z NPs.


Assuntos
Cobre/uso terapêutico , Nanopartículas Metálicas/uso terapêutico , Neoplasias/radioterapia , Radiossensibilizantes/uso terapêutico , Bismuto/química , Bismuto/uso terapêutico , Cobre/química , Relação Dose-Resposta a Droga , Humanos , Nanopartículas Metálicas/química , Método de Monte Carlo , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Óxidos/química , Óxidos/uso terapêutico , Radiossensibilizantes/química , Dosagem Radioterapêutica
13.
Chem Asian J ; 16(13): 1820-1831, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34014032

RESUMO

In this investigation, a melamine electrochemical sensor has been developed by using wet-chemically synthesized low-dimensional aggregated nanoparticles (NPs) of ZnO-doped Co3 O4 as sensing substrate that were decorated onto flat glassy carbon electrode (GCE). The characterization of NPs such as UV-Vis, FTIR, XRD, XPS, EDS, and FESEM was done for detailed investigations in optical, functional, structural, elemental, and morphological analyses. The ZnO-doped Co3 O4 NPs decorated GCE was used as a sensing probe to analyze the target chemical melamine in a phosphate buffer at pH 5.7 by applying differential pulse voltammetry (DPV). It exhibited good performances in terms of sensor analytical parameters such as large linear dynamic range (LDR; 0.15-1.35 mM) of melamine detection, high sensitivity (80.6 µA mM-1 cm-2 ), low limit of detection (LOD; 0.118±0.005 mM), low limit of quantification (LOQ; 0.393 mM), and fast response time (30 s). Besides this, the good reproducibility (in several hours) and repeatability were investigated under identical conditions. Moreover, it was implemented to measure the long-time stability, electron mobility, less charge-transfer resistance, and analyzed diffusion-controlled process for the oxidation reaction of the NPs assembled working GCE electrode, which showed outstanding chemical sensor performances. For validation, real environmental samples were collected from various water sources and investigated successfully with regard to the reliability of the selective melamine detection with prepared NPs coated sensor probe. Therefore, this approach might be introduced as an alternative route in the sensor technology to detect selectively unsafe chemicals by an electrochemical method with nanostructure-doped materials for the safety of environmental, ecological, healthcare fields in a broad scale.


Assuntos
Carbono/química , Cobalto/química , Nanopartículas Metálicas/química , Óxidos/química , Triazinas/química , Água/química , Óxido de Zinco/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Monitoramento Ambiental , Reprodutibilidade dos Testes , Poluentes Químicos da Água/química
14.
Environ Geochem Health ; 43(5): 2065-2080, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33392897

RESUMO

This paper attempts to evaluate the mineralogical and chemical composition of sedimentary limestone mine waste alongside its mineral carbonation potential. The limestone mine wastes were recovered as the waste materials after mining and crushing processes and were analyzed for mineral, major and trace metal elements. The major mineral composition discovered was calcite (CaCO3) and dolomite [CaMg(CO3)2], alongside other minerals such as bustamite [(Ca,Mn)SiO3] and akermanite (Ca2MgSi2O7). Calcium oxide constituted the greatest composition of major oxide components of between 72 and 82%. The presence of CaO facilitated the transformation of carbon dioxide into carbonate form, suggesting potential mineral carbonation of the mine waste material. Geochemical assessment indicated that mean metal(loid) concentrations were found in the order of Al > Fe > Sr > Pb > Mn > Zn > As > Cd > Cu > Ni > Cr > Co in which Cd, Pb and As exceeded some regulatory guideline values. Ecological risk assessment demonstrated that the mine wastes were majorly influenced by Cd as being classified having moderate risk. Geochemical indices depicted that Cd was moderately accumulated and highly enriched in some of the mine waste deposited areas. In conclusion, the limestone mine waste material has the potential for sequestering CO2; however, the presence of some trace metals could be another important aspect that needs to be considered. Therefore, it has been shown that limestone mine waste can be regarded as a valuable feedstock for mineral carbonation process. Despite this, the presence of metal(loid) elements should be of another concern to minimize potential ecological implication due to recovery of this waste material.


Assuntos
Carbonato de Cálcio , Resíduos Industriais/análise , Mineração , Carbonato de Cálcio/análise , Compostos de Cálcio/análise , Compostos de Cálcio/química , Dióxido de Carbono/química , Carbonatos/análise , Carbonatos/química , Monitoramento Ambiental , Poluição Ambiental , Magnésio/análise , Malásia , Metais Pesados/análise , Minerais/análise , Óxidos/análise , Óxidos/química , Oligoelementos/análise
15.
Ecotoxicol Environ Saf ; 209: 111760, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33360285

RESUMO

In this study, a simple to produce, low-cost and environment-friendly sludge based adsorbent, prepared from municipal dewatered sludge and modified by calcium oxide (CaO), is described. The enhancement effect of CaO modification on the adsorption capacity and mechanical strength of sludge based adsorbents (CaO-SA), and the modification mechanism of CaO on activated sludge are discussed. Also, the Cd(II) adsorption conditions are optimized using surface optimization experiment. The results indicated that CaO had a good effect on improving the adsorption capacity and mechanical strength of the sludge-based adsorbent. The CaO-SA adsorbent showed best performance with respect to the mechanical strength and Cd(II) adsorption capacity when prepared under 5% CaO dosage and 60 °C drying temperature. CaO modification can increase the specific surface area and calcium ion content of the sludge-based adsorbent and remove the proton of the carboxylic acid in the sludge. The Box-Behnken experimental design results revealed that the importance of operating conditions for CaO-SA adsorption of Cd(II) can be arranged in the order of adsorption time > dosage> pH> temperature. The results also indicated that the interactions between adsorption time and CaO-SA dosage, adsorption time and pH, adsorption time and temperature are all important factors affecting the Cd(II) adsorption. The optimal conditions (adsorption time of 90 min, CaO-SA dosage of 1 g/L, pH of 5 and adsorption temperature of 40 °C) for CaO-SA to adsorb Cd(II) were obtained by surface optimization, at which the Cd(II) adsorption rate could reach a value of 99.74%.


Assuntos
Cádmio/química , Poluentes Químicos da Água/química , Adsorção , Cádmio/análise , Compostos de Cálcio/química , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Óxidos/química , Temperatura , Gerenciamento de Resíduos , Poluentes Químicos da Água/análise
16.
Environ Geochem Health ; 43(7): 2679-2697, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32918158

RESUMO

To evaluate the potential of sepiolite-based materials to resolve environmental pollution problems, a study is needed which looks at the whole life cycle of material application, including the residual value of material classified as waste from the exploitation of sepiolite deposits in the region or from its processing and purification. This would also maximize value from the exploitation process and provide new potential for local waste management. We review the geographical distribution of sepiolite, its application in the treatment of potentially toxic elements in soil and across the wider landscape, an assessment of modification and compositional variation of sepiolite-based applications within site remediation and wastewater treatment. The potential of sepiolite-based technologies is widespread and a number of processes utilize sepiolite-derived materials. Along with its intrinsic characteristics, both the long-term durability and the cost-effectiveness of the application need to be considered, making it possible to design ready-to-use products with good market acceptance. From a critical analysis of the literature, the most frequently associated terms associated with sepiolite powder are the use of lime and bentonite, while fly ash ranked in the top ten of the most frequently used material with sepiolite. These add improved performance for the inclusion as a soil or wastewater treatment options, alone or applied in combination with other treatment methods. This approach needs an integrated assessment to establish economic viability and environmental performance. Applications are not commonly evaluated from a cost-benefit perspective, in particular in relation to case studies within geographical regions hosting primary sepiolite deposits and wastes that have the potential for beneficial reuse.


Assuntos
Poluição Ambiental/análise , Recuperação e Remediação Ambiental/métodos , Silicatos de Magnésio/química , Poluentes do Solo/análise , Bentonita/química , Compostos de Cálcio/química , Cinza de Carvão/química , Óxidos/química , Solo/química , Gerenciamento de Resíduos , Purificação da Água
17.
IET Nanobiotechnol ; 14(8): 695-700, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33108326

RESUMO

A simple ultrasonic assisted chemical technique was used to synthesise cadmium oxide (CdO) nanoparticles (NPs) and CdO NPs/c-Multiwalled carbon nanotube (c-MWCNT) nanocomposite fibres.To confirm the physio-chemico properties and to analyse surface morphology of the obtained nanomaterials X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM) were performed. To evaluate the anti-cancer property of CdO NPs, c-MWCNT NPs and CdO NPs/c-MWCNT nanocomposite fibres, an anti-proliferative assay test (Methylthiazolyl diphenyl- tetrazolium bromide - MTT assay) were performed on HeLa cells which further estimated IC50 value (Least concentration of sample in which nearly 50% of cells remain alive) under in-vitro conditions. On comparison, CdONPs/c-MWCNT based system was found to be superior by achieving 52.3% cell viability with its minimal IC50 value of 31.2 µg/ml. Lastly, the CdO NPs based system was taken up for an apoptotic study using DNA fragmentation assay for estimating its ability to cleave the DNA of the HeLa cells into internucleosomal fragments using the agarose gel electrophoresis method. In conclusion, based on our observations, CdO NPs/c-MWCNT hybrid based system can be further used for the development of efficient drug delivery and therapeutic systems.


Assuntos
Compostos de Cádmio/química , Compostos de Cádmio/farmacologia , Nanopartículas Metálicas/administração & dosagem , Nanocompostos/química , Nanotubos de Carbono/química , Óxidos/química , Óxidos/farmacologia , Neoplasias do Colo do Útero/tratamento farmacológico , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Feminino , Células HeLa , Humanos , Técnicas In Vitro , Nanopartículas Metálicas/química , Nanocompostos/administração & dosagem , Neoplasias do Colo do Útero/patologia
18.
Nanotoxicology ; 14(8): 1118-1126, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32877261

RESUMO

Metal oxide nanoparticles (MO-NPs) have unique structural characteristics, exceptionally high surface area, strong mechanical stability, catalytic activities, and are biocompatible. Consequently, MO-NPs have recently attracted considerable interest in the field of imaging-guided therapeutic and biosensing applications. This study aims to develop Quantitative Structure-Activity Relationships (QSAR) for the prediction of cell viability of MO-NPs. The QSAR model based on the so-called optimal descriptors which calculated with a simplified molecular input-line entry system (SMILES). The Monte Carlo technique applied to calculate correlation weights for SMILES fragments. Factually, the optimal descriptor for SMILES is the summation of the correlation weights. The model of cytotoxicity is one variable correlation between cytotoxicity and the above optimal descriptor. The Correlation Intensity Index (CII) is a possible criterion of the predictive potential of the model. Applying the CII as a component of the target function in the Monte Carlo optimization routine, employed by the CORAL program, that is designed to find a predictive relationship between the optimal descriptor and cytotoxicity of MO-NPs, improves the statistical quality of the model. The significance of different eclectic features, in terms of whether they increase/decrease cell viability, i.e. decrease or increase cytotoxicity, is also discussed. Numerical data on 83 experimental samples of MO-NPs activity under different conditions taken from the literature are applied for the "nano-QSAR" analysis.


Assuntos
Nanopartículas Metálicas/toxicidade , Modelos Teóricos , Óxidos/toxicidade , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Células HT29 , Células Hep G2 , Humanos , Células MCF-7 , Nanopartículas Metálicas/química , Método de Monte Carlo , Óxidos/química , Relação Quantitativa Estrutura-Atividade , Ratos
19.
J Pharm Biomed Anal ; 186: 113299, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32375106

RESUMO

In this study the metabolite profiling of citalopram with the use of human liver microsomes as well as the complementary photocatalytic method were established. This strategy allowed the detection of five metabolites of citalopram including 3-hydroxycitalopram and 3-oxocitalopram which were found as a new and not previously described metabolites of this drug The photocatalytic simulation of metabolism was carried out using tungsten (VI) oxide nanopowders with the different particle sizes, which allowed to examine the effect of this photocatalyst parameter on the mapping of metabolic processes. The accurate characterization of all observed structures was possible due to the use of ultra-high-pressure liquid chromatography and high-resolution mass spectrometry combined system as a highly useful technique in drug metabolism studies. In order to perform the toxicity prediction of citalopram and its metabolites, the acute toxicity to rodents, as well as genotoxicity, carcinogenicity, developmental toxicity and receptor-mediated toxicity was calculated basing on the in silico tools.


Assuntos
Citalopram/toxicidade , Inibidores Seletivos de Recaptação de Serotonina/toxicidade , Animais , Catálise , Cromatografia Líquida de Alta Pressão , Citalopram/química , Citalopram/metabolismo , Simulação por Computador , Humanos , Dose Letal Mediana , Camundongos , Microssomos Hepáticos/metabolismo , Modelos Biológicos , Testes de Mutagenicidade , Óxidos/química , Tamanho da Partícula , Processos Fotoquímicos , Ratos , Inibidores Seletivos de Recaptação de Serotonina/química , Inibidores Seletivos de Recaptação de Serotonina/metabolismo , Software , Espectrometria de Massas por Ionização por Electrospray , Testes de Toxicidade Aguda , Tungstênio/química
20.
Nat Commun ; 11(1): 1735, 2020 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-32269223

RESUMO

The therapeutic effect of reactive oxygen species (ROS)-involved cancer therapies is significantly limited by shortage of oxy-substrates, such as hypoxia in photodynamic therapy (PDT) and insufficient hydrogen peroxide (H2O2) in chemodynamic therapy (CDT). Here, we report a H2O2/O2 self-supplying nanoagent, (MSNs@CaO2-ICG)@LA, which consists of manganese silicate (MSN)-supported calcium peroxide (CaO2) and indocyanine green (ICG) with further surface modification of phase-change material lauric acid (LA). Under laser irradiation, ICG simultaneously generates singlet oxygen and emits heat to melt the LA. The exposed CaO2 reacts with water to produce O2 and H2O2 for hypoxia-relieved ICG-mediated PDT and H2O2-supplying MSN-based CDT, acting as an open source strategy for ROS production. Additionally, the MSNs-induced glutathione depletion protects ROS from scavenging, termed reduce expenditure. This open source and reduce expenditure strategy is effective in inhibiting tumor growth both in vitro and in vivo, and significantly improves ROS generation efficiency from multi-level for ROS-involved cancer therapies.


Assuntos
Tratamento Farmacológico , Fotoquimioterapia , Espécies Reativas de Oxigênio/metabolismo , Animais , Circulação Sanguínea , Compostos de Cálcio/química , Linhagem Celular Tumoral , Sobrevivência Celular , Sinergismo Farmacológico , Feminino , Humanos , Peróxido de Hidrogênio/metabolismo , Verde de Indocianina/química , Ácidos Láuricos/sangue , Ácidos Láuricos/química , Imageamento por Ressonância Magnética , Manganês/química , Camundongos Endogâmicos BALB C , Nanopartículas/química , Nanopartículas/ultraestrutura , Óxidos/química , Silicatos/química , Superóxidos/metabolismo , Distribuição Tecidual
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