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1.
Niger J Clin Pract ; 23(8): 1068-1072, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32788483

RESUMO

Aims: The aim of this study was to compare the influence of operators on the microhardness and compressive strength of mineral trioxide aggregate (MTA). Materials and Methods: Forty dental specialists were asked to prepare a series of MTA samples. The tested material was ProRoot MTA (DentsplyMaillefer, Switzerland). Each participant prepared one sample to a consistency they considered acceptable for use in practice (improvised group) and another one according to the manufacturer's recommended water-to-powder (WP) ratio (pre-weighed group). The samples were incubated at 37°C and 95% humidity for 4 days. Parameters evaluated in this study were microhardness and compressive strength. Results: Operators mixed MTA samples with varying WP ratios. However, there was no significant difference between the microhardness and compressive strength values of MTA samples between the improvised, the pre-weighed and the control groups. MTA was mixed in a thicker consistency than the manufacturers recommended ratio (0.33) by 62.5% of the operators. Conclusion: According to the results of this study, even though the WP ratios that were utilized in the clinical setting vary, microhardness and compressive strength values of MTA was not significantly affected.


Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Força Compressiva , Teste de Materiais/métodos , Óxidos/química , Materiais Restauradores do Canal Radicular , Silicatos/química , Estudos de Casos e Controles , Combinação de Medicamentos , Dureza , Humanos , Água
2.
PLoS One ; 15(8): e0236718, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797052

RESUMO

High-flow low-expansion backfill materials have been developed to improve difficult slurry pipeline transport and poor roof-contact effect of many filling materials. The fly ash content was fixed at 80%, with 8.5% - 9.5% mineral powder content, 8.5% - 9.5% lime, 2% - 3% desulfurized gypsum, 0.9% - 1.2% sodium carbonate, and 0.01% - 0.02% aluminum powder content. The prepared backfill material processed good fluidity, with the expansion rate of the hardened material reaching 2% - 3%, and compressive strength on 90 d reaching 4 MPa-5.5 MPa. SEM observations indicated that as the aluminum content increased, ettringite on bubble walls transformed from a fine-needle to needle-rod shape. Secondly, the hydration products of the system were mainly hydrated calcium silicate gel and ettringite, which interconnected and promoted the formation of the structure. The backfill material has extensive sources of raw materials, low cost, simple filling process, and good filling effect.


Assuntos
Cinza de Carvão/química , Mineração , Compostos de Cálcio/química , Sulfato de Cálcio/química , Óxidos/química , Água/química
3.
PLoS One ; 15(8): e0237389, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797116

RESUMO

In the present work, a series of magnetically separable Fe3O4/g-C3N4/MoO3 nanocomposite catalysts were prepared. The as-prepared catalysts were characterized by XRD, EDX, TEM, FT-IR, UV-Vis DRS, TGA, PL, BET and VSM. The photocatalytic activity of photocatalytic materials was evaluated by catalytic degradation of tetracycline solution under visible light irradiation. Furthermore, the influences of weight percent of MoO3 and scavengers of the reactive species on the degradation activity were investigated. The results showed that the Fe3O4/g-C3N4/MoO3 (30%) nanocomposites exhibited highest removal ability for TC, 94% TC was removed during the treatment. Photocatalytic activity of Fe3O4/g-C3N4/MoO3 (30%) was about 6.9, 5, and 19.9-fold higher than those of the MoO3, g-C3N4, and Fe3O4/g-C3N4 samples, respectively. The excellent photocatalytic performance was mainly attributed to the Z-scheme structure formed between MoO3 and g-C3N4, which enhanced the efficient separation of the electron-hole and sufficient utilization charge carriers for generating active radials. The highly improved activity was also partially beneficial from the increase in adsorption of the photocatalysts in visible range due to the combinaion of Fe3O4. Superoxide ions (·O2-) was the primary reactive species for the photocatalytic degradation of TC, as degradation rate were decreased to 6% in solution containing benzoquinone (BQ). Data indicate that the novel Fe3O4/g-C3N4/MoO3 was favorable for the degradation of high concentrations of tetracycline in water.


Assuntos
Óxido Ferroso-Férrico/química , Grafite/química , Molibdênio/química , Nanocompostos/química , Compostos de Nitrogênio/química , Óxidos/química , Processos Fotoquímicos , Tetraciclina/química , Água/química , Catálise , Luz , Imãs/química , Tetraciclina/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
4.
Ecotoxicol Environ Saf ; 204: 111097, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32784016

RESUMO

Iron (hydr)oxide-natural organic matter (NOM) colloids, the dominant components of soil, usually occur in varied circumstances and may affect Hg transport and fate in soil. This study aims to reveal the Hg binding to preformed composites rather than only focusing on Hg retention by iron (hydr)oxides in the presence of NOM. Ferrihydrite-humic acid (FH-HA) is chosen as a representative composite, and the effect of the complexation method and FH morphology on Hg binding to various composites is evaluated. Three types of composites are developed: a dense coprecipitated composite (p-d-f), a gel-like adsorbed composite (a-g-f) and a dense adsorbed (a-d-f) composite. Batch sorption and stirred-flow kinetic tests together with surface property analysis and modern spectral analyses are carried out to explore the binding behavior of Hg to the three composites and clarify the interactions in the ternary systems of FH-HA-Hg. The results show that the Hg sorption isotherms all fit well with the Langmuir model, and the maximum sorption capacities follow the order a-g-f> a-d-f > p-d-f, implying that the adsorbed composite is more favorable than the coprecipitated composite for Hg binding and a gel morphology is more beneficial than a dense morphology. The stirred-flow experiments show that the adsorbed composite has a small advantage in Hg sorption compared to the coprecipitated composite and that the gel-like composite can adsorb more Hg at a faster rate than the dense composite. Both FH and HA participate in Hg sorption, and FH-HA-Hg complexes are speculated to form. These findings are helpful to better understand the mobility and fate of Hg in soils, as well as the associated dynamic model for predicting Hg behavior in the environment where the iron (hydr) oxide-NOM composites are pre-existed.


Assuntos
Mercúrio/química , Adsorção , Coloides , Compostos Férricos/química , Substâncias Húmicas/análise , Ferro/análise , Cinética , Mercúrio/análise , Compostos Orgânicos/química , Óxidos/química , Solo/química , Propriedades de Superfície
5.
PLoS One ; 15(8): e0237612, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790731

RESUMO

Seventeen glass vessels and twenty glass beads recovered from the excavations at the ancient city of Malindi and the archaeological site of Mambrui in Kenya, east Africa were analysed using electron probe microanalysis (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The results show that all of the glass samples are soda-lime-silica glass. They belong to the high alumina -plant ash glass type, characterised by high alumina and relatively low calcium contents, widely distributed in eastern (10th- 16th centuries AD) and southern Africa (13th - 15th centuries AD), Central Asia (9th- 14th centuries AD) and southeast Asia (12th- 13th centuries AD), made with plant ashes and sands. This is an understudied glass type for which previous research has indicated there were three types. When compared with published research on such glasses using Zr, Ti, Ba, Cr, La, Li, Cs, Na2O, MgO and CaO we have identified at least four different compositional groups of v-Na-Al glass: Types A, B, C and D. By comparing the results with contemporary v-Na-Al glass vessels and beads from Central Asia, Africa, and southeast Asia we show that most of the Malindi and Mambrui glass share similar characteristics to the compositions of Mapungubwe Oblate and some of the Madagascar glass beads from southern Africa. They belong to Type A v-Na-Al glass which is characterised by an elevated level of Ti and Ba and a relatively high ratios of Cr/La, relatively low Zr concentrations and low ratios of Zr/Ti. Differences in Zr, Li, MgO and Na2O concentrations in Type A glass indicates that there are subgroups which might derive from different glass workshop(s) specialising in Type A v-Na-Al glass production. Comparison with the chemical compositions of glass from Ghazni, Afghanistan and Termez, Uzbekistan, and by using lead isotope analysis, we suggest v-Na-Al glass was manufactured in Central Asia and possibly worked into vessels and beads there.


Assuntos
Compostos de Cálcio/química , Vidro/química , Óxidos/química , Plantas/química , Dióxido de Silício/química , Hidróxido de Sódio/química , Oligoelementos/análise , Oligoelementos/história , África Oriental , Óxido de Alumínio , Arqueologia , História do Século XV , História do Século XVI , Oceano Índico , Marcação por Isótopo/métodos , Quênia , Espectrometria de Massas
6.
Int J Nanomedicine ; 15: 4607-4623, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32636621

RESUMO

Aim: The interaction of NPs with biological systems may reveal useful details about their pharmacodynamic, anticancer and antibacterial effects. Methods: Herein, the interaction of as-synthesized Co3O4 NPs with HSA was explored by different kinds of fluorescence and CD spectroscopic methods, as well as molecular docking studies. Also, the anticancer effect of Co3O4 NPs against leukemia K562 cells was investigated by MTT, LDH, caspase, real-time PCR, ROS, cell cycle, and apoptosis assays. Afterwards, the antibacterial effects of Co3O4 NPs against three pathogenic bacteria were disclosed by antibacterial assays. Results: Different characterization methods such as TEM, DLS, zeta potential and XRD studies proved that fabricated Co3O4 NPs by sol-gel method have a diameter of around 50 nm, hydrodynamic radius of 177 nm with a charge distribution of -33.04 mV and a well-defined crystalline phase. Intrinsic, extrinsic, and synchronous fluorescence as well as CD studies, respectively, showed that the HSA undergoes some fluorescence quenching, minor conformational changes, microenvironmental changes as well as no structural changes in the secondary structure, after interaction with Co3O4 NPs. Molecular docking results also verified that the spherical clusters with a dimension of 1.5 nm exhibit the most binding energy with HSA molecules. Anticancer assays demonstrated that Co3O4 NPs can selectively lead to the reduction of K562 cell viability through the cell membrane damage, activation of caspase-9, -8 and -3, elevation of Bax/Bcl-2 mRNA ratio, ROS production, cell cycle arrest, and apoptosis. Finally, antibacterial assays disclosed that Co3O4 NPs can stimulate a promising antibacterial effect against pathogenic bacteria. Conclusion: In general, these observations can provide useful information for the early stages of nanomaterial applications in therapeutic platforms.


Assuntos
Antibacterianos/farmacologia , Antineoplásicos/farmacologia , Cobalto/química , Cobalto/farmacologia , Nanopartículas Metálicas/química , Óxidos/química , Óxidos/farmacologia , Albumina Sérica Humana/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antineoplásicos/química , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cobalto/metabolismo , Escherichia coli/efeitos dos fármacos , Humanos , Células K562 , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Óxidos/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Albumina Sérica Humana/química , Staphylococcus aureus/efeitos dos fármacos , Difração de Raios X
7.
Nature ; 583(7816): 453-458, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32669693

RESUMO

Manganese is one of the most abundant elements on Earth. The oxidation of manganese has long been theorized1-yet has not been demonstrated2-4-to fuel the growth of chemolithoautotrophic microorganisms. Here we refine an enrichment culture that exhibits exponential growth dependent on Mn(II) oxidation to a co-culture of two microbial species. Oxidation required viable bacteria at permissive temperatures, which resulted in the generation of small nodules of manganese oxide with which the cells associated. The majority member of the culture-which we designate 'Candidatus Manganitrophus noduliformans'-is affiliated to the phylum Nitrospirae (also known as Nitrospirota), but is distantly related to known species of Nitrospira and Leptospirillum. We isolated the minority member, a betaproteobacterium that does not oxidize Mn(II) alone, and designate it Ramlibacter lithotrophicus. Stable-isotope probing revealed 13CO2 fixation into cellular biomass that was dependent upon Mn(II) oxidation. Transcriptomic analysis revealed candidate pathways for coupling extracellular manganese oxidation to aerobic energy conservation and autotrophic CO2 fixation. These findings expand the known diversity of inorganic metabolisms that support life, and complete a biogeochemical energy cycle for manganese5,6 that may interface with other major global elemental cycles.


Assuntos
Bactérias/metabolismo , Crescimento Quimioautotrófico , Manganês/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Ciclo do Carbono , Dióxido de Carbono/metabolismo , Técnicas de Cocultura , Perfilação da Expressão Gênica , Isótopos , Manganês/química , Compostos de Manganês/química , Compostos de Manganês/metabolismo , Oxirredução , Óxidos/química , Óxidos/metabolismo , Filogenia
8.
Chemosphere ; 260: 127500, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32688308

RESUMO

Lithium (Li+) is used in various applications involving pharmaceuticals, textile dyes, and batteries. Therefore, the demand for environmentally friendly and effective materials for Li+ uptake and recovery continues to increase. Herein, rice husk (RH) and coconut shell (CS) biomasses were used to fabricate honeycomb-networked biochar (BC) precursors via slow pyrolysis. RHBC- and CSBC-based MnO2 composites were synthesized by depositing MnO2 in various ratios onto RHBC and CSBC by varying the KMnO4 concentration (2%, 3%, and 4%), followed by simple ultrasonication and heat-treatment methodologies. The structural and physicochemical properties of all of the fabricated composites were analyzed using several different instrumental methods. The batch adsorption experiments were performed for comparative Li+-adsorption studies of RHBC-Mnx and CSBC-Mnx composites by optimizing several parameters (pH, adsorbent dose, Li+ initial concentration, and contact time). The comparative adsorption analysis revealed that the RHBC-Mnx composites exhibited stronger Li+-adsorption ability than the CSBC-Mnx composites and that increasing the MnO2 deposition to 3% in both cases led to maximum Li+ adsorption capacities (62.85 mg g-1 and 57.8 mg g-1), respectively. The kinetic studies show that Li+ adsorption proceeds through the pseudo-second-order mechanism. Li+ recovery was successfully carried out using HCl (eluting agent), thereby demonstrating the benefits of synthesized composites at the industrial scale. The current work indicates that the fabricated RHBC-Mnx and CSBC-Mnx composites may have potential for use as economical composites in eco-friendly applications such as Li+ adsorption and recovery from aqueous media.


Assuntos
Carvão Vegetal/química , Cocos/química , Lítio/análise , Compostos de Manganês/química , Oryza/química , Óxidos/química , Poluentes Químicos da Água/análise , Adsorção , Fontes de Energia Elétrica , Íons , Cinética , Resíduos Sólidos/análise
9.
Chemosphere ; 260: 127629, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32698117

RESUMO

Polychlorinated biphenyls are synthetic industrial organic substances. These persistent pollutants occur in nature causing high ecological risks and damage to human health. Magnetoferritin nanoparticles composed of apoferritin protein shell surrounding synthetically prepared iron-based nanoparticles seem to be a promising candidate for polychlorinated biphenyls elimination. Properties of magnetoferritin, as a redox activity, a biocompatible character, high application possibilities and a close relationship with the human body promoted ours in vitro investigation of the magnetoferritin catalytic activity in the presence of representative 2,4,4'-trichlorobiphenyl. Basic physico-chemical properties of magnetoferritin were determined by ultraviolet and visible spectrophotometry, dynamic light scattering, zeta potential measurements, superconducting quantum interference device magnetometry and atomic force microscopy. The remediation effect of magnetoferritin on 2,4,4'-trichlorobiphenyl was demonstrated by the use of gas chromatography in combination with infrared spectroscopy.


Assuntos
Apoferritinas/química , Ferro/química , Óxidos/química , Bifenilos Policlorados/química , Poluentes Ambientais , Humanos , Nanopartículas/química
10.
Chemosphere ; 260: 127587, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32663673

RESUMO

In this work, a three-dimension grapnene-PbO2 (3DG-PbO2) composite anode was prepared using coelectrodeposition technology for electrocatalytic oxidation of perfluorooctane sulfonate (PFOS). The effect of 3DG on the surface morphology, structure and electrocatalytic activity of PbO2 electrode was investigated. The results indicated that the 3DG-PbO2-0.08 anode (3DG concentration in electrodeposition solution was 0.08 g L-1) possessed the best electrocatalytic activity due to its stronger ·OH radicals generation capacity, more active sites and smaller charge-transfer resistance. The degradation rate constant of PFOS on 3DG-PbO2-0.08 anode was 2.33 times than that of pure PbO2 anode. Additionally, the by-products formed in electrocatalytic degradation of PFOS were identified and a PFOS degradation pathway was proposed accordingly, which was dominated by the dissociation of -CF2- groups via the attack of ·OH radicals. Finally, the toxicity evolution of degradation solution was examined to evaluate the ecological risk of electrocatalytic oxidation of PFOS by acute toxicity assays to zebrafish embryos.


Assuntos
Ácidos Alcanossulfônicos/análise , Técnicas Eletroquímicas/métodos , Fluorcarbonetos/análise , Grafite/química , Chumbo/química , Nanocompostos/química , Óxidos/química , Titânio/química , Poluentes Químicos da Água/análise , Ácidos Alcanossulfônicos/toxicidade , Animais , Eletrodos , Galvanoplastia , Embrião não Mamífero/efeitos dos fármacos , Fluorcarbonetos/toxicidade , Oxirredução , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
11.
Food Chem ; 328: 127121, 2020 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-32474241

RESUMO

Chlorine dioxide (ClO2) gas was utilized for detoxifying aflatoxin B1 (AFB1) in corn for the first time. Four degradation compounds were identified by LC-MS as C17H13O8, C17H15O10, C16H15O10, and C15H11O8. Structurally, the biological activity of ClO2-treated AFB1 was removed due to the disappearance of C8-C9 double bond in the furan ring and the modification of cyclopentanone and methoxy after ClO2 treatment. The cell viability assay on human embryo hepatocytes confirmed little toxicity of the degradation products. The degradation efficiency of AFB1 on corn peaked near 90.0% under the optimized conditions and reached 79.6% for low initial contamination of AFB1 at 5-20 µg/kg. Accordingly, ClO2 has the potential to be developed into an effective, efficient, and economic approach to detoxify AFB1 in grains.


Assuntos
Aflatoxina B1/química , Compostos Clorados/química , Cloro/química , Óxidos/química , Zea mays/química , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas
12.
PLoS One ; 15(6): e0234136, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32520947

RESUMO

Groundwater treatment sludge is a Fe/Mn-bearing waste that is mass produced in groundwater treatment plant. In this study, sludge was converted to a magnetic adsorbent (MA) by adding ascorbate. The sludge was weakly magnetised in the amorphous form with Fe and Mn contents of 28.8% and 8.1%, respectively. After hydrothermal treatment, Fe/Mn oxides in the sludge was recrystallised to siderite and rhodochrosite, with jacobsite as the intermediate in the presence of ascorbate. With an increment in ascorbate dosage, the obtained magnetic adsorbent had a significant increase in chromate adsorption but a decrease in magnetisation. When the Mascorbate/MFe molar ratio was 10, the produced MA-10 was a dumbbell-shaped nanorod with a length of 2-5 µm and a diameter of 0.5-1 µm. This MA-10 showed 183.2 mg/g of chromate adsorption capacity and 2.81 emu/g of magnetisation. The mechanism of chromate adsorption was surface coprecipitation of the generated Cr3+ and Fe3+/Mn4+ from redox reaction between chromate and siderite/rhodochrosite on MA-10, separately. This study demonstrated an efficient recycling route of waste sludge from groundwater treatment to produce MA for treating chromate-bearing wastewater.


Assuntos
Cromatos/química , Magnetismo , Nanotubos/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Carbonatos/química , Compostos Férricos/química , Ferro/química , Cinética , Manganês/química , Oxirredução , Óxidos/química
13.
Chemosphere ; 259: 127427, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32599385

RESUMO

Spinel oxides, e.g., NiCo2O4, is a promising catalyst for the catalytic oxidation of toluene. Understanding and designing versatile NiCo2O4 spinel is important for low-temperature toluene oxidation. Here, we investigated the surface-characteristic-dependent degradation activity of NiCo2O4 crystals through experiment and characterization. NiCo2O4 nanosheet using ethanol as solvent (named E--NiCo2O4) exposing {110} crystal planes exhibited the lowest temperature toluene oxidation. The T99 of toluene conversion was 256 °C, which is much lower than that of NiCo2O4 nanosheet using ethylene glycol as solvent (named EG--NiCo2O4), NiCo2O4 octahedron (named O--NiCo2O4) and NiCo2O4 truncated octahedron (named TO--NiCo2O4). Characterization using various techniques such as XRD, TEM, BET, XPS, H2-TPR and CO2-TPD showed that Co3+ and surface adsorbed oxygen (Osur) enriched surface, excellent redox properties and effective diffusion of the reaction product reasonably explain the enhancement in catalytic activity over the E--NiCo2O4. The research reveals that the effect of specific crystal planes and solvent was the key factor to govern the activity of low-temperature toluene oxidation.


Assuntos
Óxido de Alumínio/química , Óxido de Magnésio/química , Tolueno/química , Adsorção , Catálise , Temperatura Baixa , Oxirredução , Óxidos/química , Oxigênio/química , Solventes
14.
Chemosphere ; 257: 127112, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32474150

RESUMO

Given the millions of coal-fired power stations worldwide and the generalization of co-firing technologies in the near future, the aqueous extraction experiments were taken to study the effects of oxides on Cr mobility in ashes through SiO2-Al2O3-Fe2O3-CaO system. The results identify that both the component and the species of Cr in samples are vital factors to govern the fate of Cr during combustion. Although Cr-oxide hardly reacts with Al2O3, SiO2, and mixtures at 900 °C, the immobilization of Cr in Si-Al glass is ascribable to the heat-driven phase transformation of Cr-rich clay. The strong capture of Cr-oxide by CaO leads to the primary extraction of active Cr with the high toxicity and mobility; however, the opposite effect is found by Fe2O3. But the interactions of Al-/Si- oxides with others can trigger some changes in Cr mobility, wherein there is the lowest mobility of Cr in the case of Cr entering into the structures of Fe-rich SiO2/Si-Al glass during combustion. Thus, without regard to the sample source, it is effective to reduce the environmental risk of Cr in ashes through raising SiO2 and reducing MCaO/MFe2O3 < 5/4 prior to combustion.


Assuntos
Cromo/análise , Modelos Químicos , Cromo/química , Carvão Mineral/análise , Cinza de Carvão/química , Compostos Férricos , Óxidos/química , Dióxido de Silício
15.
Chemosphere ; 257: 127164, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32480087

RESUMO

The present work describes the synthesis of niobium oxide nanochannels (Nb2O5NCs) with high surface area, porosity, photocurrent density, and photoelectrochemical stability as photocatalyst. The Nb2O5NCs were prepared by electrochemical anodization of niobium foil in different electrolytes: 1 M H2SO4 containing 0.4 wt% HF (S1); glycerol containing 0.4 M NH4F (S2); 0.25 g NH4F with 4 vol% water in glycol at 50 °C (S3); and glycerol containing 10 wt% K2HPO4, at 130 °C (S4, annealed in air; S5, annealed in N2). All the Nb2O5NCs showed well-organized arrays of nanochannels grown on the Nb foil, with tube diameters in the order S4

Assuntos
Corantes/química , Nióbio/química , Purificação da Água/métodos , Compostos Orgânicos , Óxidos/química , Fotólise , Titânio/química
16.
Int J Nanomedicine ; 15: 3843-3850, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32581534

RESUMO

Purpose: Despite tremendous results achieved by immune checkpoint inhibitors, most patients are not responders, mainly because of the lack of a pre-existing anti-tumor immune response. Thus, solutions to efficiently prime this immune response are currently under intensive investigations. Radiotherapy elicits cancer cell death, generating an antitumor-specific T cell response, turning tumors in personalized in situ vaccines, with potentially systemic effects (abscopal effect). Nonetheless, clinical evidence of sustained anti-tumor immunity as abscopal effect are rare. Methods: Hafnium oxide nanoparticles (NBTXR3) have been designed to increase energy dose deposit within cancer cells. We examined the effect of radiotherapy-activated NBTXR3 on anti-tumor immune response activation and abscopal effect production using a mouse colorectal cancer model. Results: We demonstrate that radiotherapy-activated NBTXR3 kill more cancer cells than radiotherapy alone, significantly increase immune cell infiltrates both in treated and in untreated distant tumors, generating an abscopal effect dependent on CD8+ lymphocyte T cells. Conclusion: These data show that radiotherapy-activated NBTXR3 could increase local and distant tumor control through immune system priming. Our results may have important implications for immunotherapeutic agent combination with radiotherapy.


Assuntos
Antineoplásicos Imunológicos/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/radioterapia , Háfnio/farmacologia , Óxidos/farmacologia , Animais , Antineoplásicos Imunológicos/química , Antineoplásicos Imunológicos/farmacocinética , Disponibilidade Biológica , Linfócitos T CD8-Positivos/imunologia , Neoplasias Colorretais/imunologia , Feminino , Háfnio/química , Háfnio/farmacocinética , Nanopartículas Metálicas/administração & dosagem , Nanopartículas Metálicas/química , Camundongos Endogâmicos BALB C , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/radioterapia , Óxidos/química , Óxidos/farmacocinética
17.
Chemosphere ; 257: 127215, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32505950

RESUMO

Red mud, as industrial solid waste, causes severe environmental problems such as soil alkalization and groundwater pollution. In this work, we researched and developed the red mud as a selective catalytic reduction catalyst for NOx removal with NH3 (NH3-SCR). After selective dissolution and specific heat treatment, different Ce precursors were used to modifying its physical and chemical properties. The results showed that Ce(NO3)3 and Ce(NH4)2(NO3)6 modified red mud (RMcn and RMcan) had excellent SCR performance below 300 °C. Ce(SO4)2 modified red mud (RMcs) showed relatively low NOx conversions at 200-300 °C. The redox property was improved with the Ce(NO3)3 and Ce(NH4)2(NO3)6, while depressed with the Ce(SO4)2. Agglomerates generated on the RMcs and blocked the accumulated pores due to the formation of Ce2(SO4)3. The surface acidity of RMcs enhanced with increased adsorption for ammonia. However, these new adsorbed ammonia species, highly related to the sulfate from the Ce2(SO4)3, were inert and did not react with the adsorbed or gaseous NO species at 200-300 °C. The abundant surface lattice oxygen from CeO2 microcrystals improved the catalytic oxidation capacity of the RMcn and RMcan.


Assuntos
Cério/química , Adsorção , Amônia/química , Catálise , Óxidos de Nitrogênio , Oxirredução , Óxidos/química , Oxigênio , Sulfatos/química , Propriedades de Superfície
18.
Environ Monit Assess ; 192(7): 422, 2020 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-32519186

RESUMO

Chlorine dioxide has been reported as very efficiently removing pesticides and other organic compounds from water matrixes. Due to pesticide toxicity and potential toxicity of their degradation products, it is important to monitor these compounds as environmental pollutants in ground and surface waters. Evaluating the effects of chlorine dioxide treatment is necessary, and toxicity studies are used to ascertain the severity of effects of intermediates due to incomplete degradation of the parent compounds. In this paper, for the first time, chlorine dioxide is applied and evaluated for the removal of chloroacetamide herbicides (pethoxamid and metazachlor) from waters (deionized water and Sava River water). The degradation degree of herbicides was measured by high-performance liquid chromatography, the main degradation products were identified using gas chromatography with a triple quadrupole mass detector, and the degree of mineralization was monitored by total organic carbon analysis. Four and two degradation products were identified after pethoxamid and metazachlor degradation, respectively. Total organic carbon analysis showed mineralization occurred, but it was incomplete. The mineralization and the characteristics of the degradation products obtained were tested using Daphnia magna and showed lower toxicity than the parent herbicides. The advantage of the applied treatment was a very high degradation percentage for pethoxamid removal from deionized water and Sava River water (100% and 97%, respectively), with higher mineralization efficiency (65%) than metazachlor. Slightly lower degradation efficiency in the Sava River water was due to chlorine dioxide oxidizing the herbicides and dissolved organic matter simultaneously.


Assuntos
Acetamidas , Compostos Clorados , Óxidos , Poluentes Químicos da Água , Purificação da Água , Acetamidas/análise , Acetamidas/química , Acetamidas/metabolismo , Acetamidas/toxicidade , Animais , Compostos Clorados/química , Daphnia/efeitos dos fármacos , Ecotoxicologia , Óxidos/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos
19.
Chemosphere ; 258: 127329, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540535

RESUMO

Due to the neutral charge of As(III) oxy-ions that make approaching the traditional adsorbent very improbable compared to the As(V) case, making it harder to be separated. To enhance the adsorption of As(Ш), the FeOOH coated cellulose acetate (CA) membrane doped with MnO2 nanoparticles (FeOOH@MnO2@CAM) was fabricated and then to removes As(Ш) in water through the synergistic effect of oxidation and adsorption, and the maximum adsorption capacity can reach 50.34 mg/g. FeOOH@MnO2@CAM was fabricated with CA as a substrate by dipping-precipitation phase inversion and hydrothermal method. Langmuir and pseudo-second-order model showed that As(Ш) was adsorbed by chemical interactions through the monolayer and thermodynamic showed that As(Ш) adsorption was an exothermic and spontaneous process. The results of the pH study showed that as the pH increases from 3 to 11, the adsorption capacity of As(Ш) decreases from 50.34 to 14.32 mg/g, which was attributed to the acidic environment promoting the protonation of the surface of FeOOH@MnO2@CAM, which increases the electrostatic attraction, and the alkaline environment increases electrostatic repulsion due to deprotonation. The competitive ions exhibited the PO43- significantly reduce the adsorption capacity of As(Ш),and as the PO43- content increases, the adsorption capacity of As(Ш) decreases from 29.76 to 18.57 mg/g, which was attributed to the similar chemical properties of PO43- and arsenate. Importantly, FeOOH@MnO2@CAM still maintains an adsorption capacity of 20.19 mg/g after seven cycles, demonstrating that it is a kind of environmentally friendly material to remove As(Ш) in the water environment.


Assuntos
Arsênico/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Compostos de Manganês/química , Oxirredução , Óxidos/química , Água
20.
Chemosphere ; 258: 127334, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32540536

RESUMO

Herein, MgO cathode and graphene Mn-Ce bimetallic oxide were utilized to jointly enhance the removal of toluene in pulsed discharge plasma (PDP). Compared to the common cathode, the MgO cathode enhanced the density of high energy electrons, and then induced to higher removal of toluene. However, the removal of toluene by PDP/MgO system was still insufficient, and there was a large amount of underutilized O3 in the products. Based on this, Mn-Ce/graphene catalysts were introduced into PDP/MgO system. The Mn-Ce (8:1)/graphene catalyst had the highest catalytic activity. Under the discharge power of 2.1 W, toluene degradation rate and CO2 selectivity increased by 27.5% and 22.0%, respectively. This was ascribed to the synergistic effect of the solid solution formed between MnOx and CeOx, increasing the proportion of Oads on the surface of the catalyst. The higher Oads/Olatt ratio lead to the better catalytic activity, which was conducive to the complete transformation of the intermediate products to CO2 and H2O. According to the detected products, the degradation pathway and the mechanism of toluene degradation were proposed finally. The PDP itself, field emission effect of MgO cathode and catalytic effect of Mn-Ce/graphene for jointly improve the toluene removal and CO2 selectivity.


Assuntos
Técnicas Eletroquímicas/métodos , Grafite/química , Óxido de Magnésio/química , Tolueno/isolamento & purificação , Dióxido de Carbono , Catálise , Cério/química , Eletrodos , Compostos de Manganês/química , Óxidos/química , Água
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