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1.
Environ Int ; 158: 106991, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34991252

RESUMO

Magnetite (Fe3O4) nano-particles (MNPs) have been found in human tissues and causally linked to serious illnesses. The possible negative role of MNPs has been not still fully ascertained even though MNPs might cause health effects due to their magnetic property, redox activity and surface charge. The origin of MNPs in human tissues still remains to be unambiguously identified since biological processes, natural phenomena and anthropogenic production have been proposed. According to this latter increasingly convincing hypothesis, anthropogenic MNPs might enter mainly in the human body via inhalation, penetrate deeply into the lungs and in the alveoli and also migrate into the blood circulation and gather in the extrapulmonary organs and central nervous system. In order to identify the releasing source of the potentially inhalable MNPs, we pioneered an innovative approach to rapidly investigate elemental profile and morphology of a large number of airborne micron and sub-micron-sized Fe-bearing particles (FePs). The study was performed by collecting a large amount of micron and sub-micron sized inhalable airborne FePs in trafficked and densely frequented areas of Rome (Italy). Then, we have investigated individually the elemental profile and morphology of the collected particles by means of high-spatial resolution scanning electron microscopy, energy dispersive spectroscopy and an automated software purposely developed for the metal-bearing particles analysis. On the basis of specific elemental tracing features, the investigation reveals that almost the total amount of the airborne FePs is released by the vehicle braking systems mainly in the form of magnetite. Furthermore, we point out that our approach might be more generally used to identify the releasing sources of different inorganic airborne particles and to contribute to establish more accurately the impact of specific natural or anthropogenic particles on the environment and human health.


Assuntos
Poluentes Atmosféricos , Poluentes Atmosféricos/análise , Óxido Ferroso-Férrico , Humanos , Metais/análise , Tamanho da Partícula , Espectrometria por Raios X
2.
J Hazard Mater ; 423(Pt A): 127051, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34523502

RESUMO

The aim of this study was to investigate the primary mechanism of magnetite promoting anaerobic degradation of aromatic compounds under the low-concentration sulphate conditions. Under influent conditions of benzoate at 50 mM-chemical oxygen demand (COD) and sulphate at 15 mM, magnetite promoted benzoate degradation (77.1% vs 56.3%), while the effluent sulphate concentration was slightly higher than that without magnetite (1.6 mM vs 0.7 mM), inconsistent with functional gene prediction that both sulphate respiration and sulphur compound respiration were relatively more active in the presence of magnetite. Remarkably, X-ray diffraction showed that, signal related to Fe3O4 faded away and finally was replaced by FeSO4 and FeS, indicating that magnetite participated in benzoate degradation coupled to sulphate reduction via dissimilatory Fe(III) reduction. Further X-ray photoelectron spectroscopy showed that, signal related to S0 was only detected with magnetite, suggesting the possibility of re-oxidation of sulphide to elemental sulphur coupled to Fe(III) reduction. This was further supported by the increase in abundance of Desulfuromonas acetexigens capable of growing on Fe(III). In addition, magnetite specially enriched the chemolithotrophic sulphur-disproportionating microbes, Desulfovibrio aminophilus, which might proceed the disproportionation of elemental sulphur to sulphate and sulphide to achieve a sulphur cycle for benzoate degradation.


Assuntos
Óxido Ferroso-Férrico , Sulfatos , Anaerobiose , Benzoatos , Elétrons , Compostos Férricos , Oxirredução , Enxofre
3.
Chemosphere ; 287(Pt 3): 132310, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826948

RESUMO

In this study, a nano-adsorbent was prepared for kerosene removal from water. Multiwalled carbon nanotubes (MWCNTs) were functionalized with concentrated HNO3 (nitric acid). Subsequently, Fe3O4 (magnetite) nanoparticles were deposited on the MWCNTs to prepare a magnetite/MWCNTs (Fe-MWCNTs) nanocomposite. Then, polyethylene was added to the Fe-MWCNTs to fabricate a polyethylene/magnetite/MWCNTs (PE/Fe-MWCNTs) novel nanocomposite. The nano-adsorbent was characterized using BET, FTIR, Raman, XRD, TEM, and SEM. A kerosene-water model mixture was used for adsorption tests. Several parameters: adsorption time, adsorbent dose, solution pH, solution temperature, and kerosene concentration in the kerosene-water model mixture, were analyzed during adsorption experiments. After each batch experiment, kerosene concentration was determined using high-performance liquid chromatography (HPLC). Magnetic field was used to remove the adsorbent after each experiment. The kerosene adsorption capacity and removal efficiency of the PE/Fe-MWCNTs nanocomposite (3560 mg/g and 71.2 %, respectively) were higher than those of Fe-MWCNTs, ox-MWCNTs, and fresh MWCNTs (3154 mg/g and 63.1 %, 2204 mg/g and 44.0 %, and 2092 mg/g and 41.8 %, respectively). Kerosene adsorption followed a pseudo-second-order kinetic model (R2 = 0.999) and the Langmuir isotherm model, suggesting that adsorption was uniform and homogenous process.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Purificação da Água , Adsorção , Óxido Ferroso-Férrico , Concentração de Íons de Hidrogênio , Querosene , Cinética , Polietileno , Água , Poluentes Químicos da Água/análise
4.
Chemosphere ; 286(Pt 2): 131787, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34365168

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are important mutagen prevalent in the contaminated sites, bringing potential risks to human health. Iron oxides are important natural components in soils. Pyrene removal in soil using persulfate (PS) oxidation activated by microwave (MW) and magnetite (Fe3O4) was investigated. Fe3O4 significantly promoted pyrene removal in the soil; 91.7 % of pyrene was degraded within 45 min treatment. Pyrene removal rate in the Fe3O4/MW/PS system was 5.18 and 3.00 times higher than that in the Fe3O4/PS and MW/PS systems. Increasing in Fe3O4 dosage, PS concentration, MW temperature, and soil moisture content in the selected range were conducive for pyrene degradation. SO4•-, •OH, O2•-, and 1O2 were responsible for pyrene degradation, and the conversion of Fe (Ⅱ) in the Fe3O4 to Fe (Ⅲ) contributed to the formation of O2•- and 1O2. Characteristic bands of pyrene were more obviously destroyed by the Fe3O4/MW/PS oxidation, in comparison with MW/PS oxidation. Ring hydroxylation and ring-opening reactions were the main degradation pathways of pyrene. The toxicities of the formed byproducts were significantly reduced after treatment. This study provided a promising option for pyrene contaminated soil remediation.


Assuntos
Recuperação e Remediação Ambiental , Poluentes do Solo , Óxido Ferroso-Férrico , Humanos , Micro-Ondas , Pirenos , Solo , Poluentes do Solo/análise
5.
Sci Total Environ ; 806(Pt 3): 151214, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34715225

RESUMO

Soil contamination with multiple heavy metals has always been a pressing issue, but little attention has been given to V and Cr and their chemical fractions' impacts on microorganisms because Cr2O3 usually occurs as an associated mineral in vanadium mines. To investigate this issue, samples (N1-N6) less affected by anthropogenic activities were selected for microbial analysis. The area near the refinery was heavily contaminated according to the PLI (pollution load index). Actinobacteriota, Proteobacteria, and Chloroflexi were the dominant phyla in the soil. The diversity of bacteria was positively influenced by V and Cr and negatively influenced by pH, while the abundance was positively correlated with soil nutrients. Interestingly, the influence of heavy metals in the residual fraction on the microbial community structure and functional metabolism was higher than that in the oxidizable fraction, which may be due to the relatively low heavy metal valence of the oxidizable fraction, suggesting that low valence binding forms of multivalence elements have little effect on microorganisms in the soil. Ultimately, two strains with great efficiency in reducing V and Cr were screened, and co-occurrence network characteristics with significant positive interactions suggested that Bacillus can coordinate community structure in the same niche. This research will help to explore the bioavailability of heavy metals and further achieve the bioremediation of heavy metal contamination in soil.


Assuntos
Poluentes do Solo , Vanádio , Bactérias , Biodegradação Ambiental , Óxido Ferroso-Férrico , Microbiologia do Solo , Poluentes do Solo/análise , Titânio
6.
Environ Res ; 204(Pt A): 111986, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34481818

RESUMO

A core-heteroshell structural magnetic composite of ZIF-67/Vanadium-titanium magnetite (VTM) was successfully synthesized through a feasible solvothermal method and efficiently used in activation of peroxymonosulfate (PMS) for the treatment of levofloxacin (LVF) in an aqueous solution. The catalytic activity of the ZIF-67/VTM composite in LVF degradation was thoroughly evaluated, demonstrating the LVF removal rate could reach up to 93.3% within 60 min at ZIF-67/VTM composite dosage of 100 mg/L, PMS concertation of 75 mg/L, and the natural pH of 6.4. It is quite interesting that the carbon organic skeleton (in the ZIF-67 shell) have accelerated the internal electron transformation rate of the ZIF-67/VTM composite, thus efficiently promoting the O-O band (in PMS) breakage and the redox cycle of cobalt, further favoring the free radicals generation. The quenching experiments and EPR analysis results demonstrated that ·SO4- would play a crucial role in the LVF degradation process. Surprisingly, we have found that the introduction of Cl- (at some certain dosage) would not always decrease the LVF degradation ratio, for a new reactive oxygen species (singlet oxygen) was emerged in this system. What's more, the ZIF-67 (as the wrapping structure) could stabilize the VTM (the inner structure) in changing reaction conditions, prompting a good adaptability at a wider pH range (3-10) for inhibiting the leaching of various metal ions into the aqueous solution. This novel ZIF-67/VTM composite could provide new ideas and routes for the removal of emerging pollutants from an aqueous solution.


Assuntos
Óxido Ferroso-Férrico , Levofloxacino , Peróxidos , Titânio , Vanádio
7.
Sheng Wu Gong Cheng Xue Bao ; 37(9): 3190-3200, 2021 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-34622627

RESUMO

The targeting of anti-tumor drugs is an important means of tumor treatment and reducing drug side effects. Oxygen-depleted hypoxic regions in the tumour, which oxygen consumption by rapidly proliferative tumour cells, are generally resistant to therapies. Magnetotactic bacteria (MTB) are disparate array of microorganism united by the ability to biomineralize membrane-encased, single-magnetic-domain magnetic crystals (magnetosomes) of minerals magnetite or greigite. MTB by means of flagella, migrate along geomagnetic field lines and towards low oxygen concentrations. MTB have advantage of non-cytotoxicity and excellent biocompatibility, moreover magnetosomes (BMs) is more powerful than artificial magnetic nanoparticles(MNPs). This review has generally described the biological and physical properties of MTB and magnetosomes, More work deals with MTB which can be used to transport drug into tumor based on aerotactic sensing system as well as the competition of iron which is a key factor to proliferation of tumor. In addition, we summarized the research of magnetosomes, which be used as natural nanocarriers for chemotherapeutics, antibodies, vaccine DNA. Finally, We analyzed the problems faced in the tumor treatment using of MTB and bacterial magnetosomes and prospect development trends of this kind of therapy.


Assuntos
Magnetossomos , Neoplasias , Bactérias , Óxido Ferroso-Férrico , Bactérias Gram-Negativas , Magnetismo , Neoplasias/terapia
8.
An Acad Bras Cienc ; 93(4): e20200774, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34705939

RESUMO

This study performs natural sand-based synthesis using the sonochemical route for preparing Zn-doped magnetite nanoparticles. The nanoparticles were dispersed in water as a carrier liquid to form Zn-doped magnetite aqueous ferrofluids. Structural data analysis indicated that the Zn-doped magnetite nanoparticles formed a nanosized spinel structure. With an increase in the Zn content, the lattice parameters of the Zn-doped magnetite nanoparticles tended to increase because Zn2+ has a larger ionic radius than those of Fe3+ and Fe2+. The existence of Zn-O and Fe-O functional groups in tetrahedral and octahedral sites were observed in the wavenumber range of 400-700 cm-1. The primary particles of the Zn-doped magnetite ferrofluids tended to construct chain-like structures with fractal dimensions of 1.2-1.9. The gas-like compression (GMC) plays as a better model than the Langevin theory to fit the saturation magnetization of the ferrofluids. The ferrofluids exhibited a superparamagnetic character, with their magnetization was contributed by aggregation. The Zn-doped magnetite ferrofluids exhibited excellent antibacterial activity against gram-positive and negative bacteria. It is suggested that the presence of the negatively charged surface and the nanoparticle size may contribute to the high antibacterial activity of Zn-doped magnetite ferrofluids and making them potentially suitable for advanced biomedical.


Assuntos
Óxido Ferroso-Férrico , Areia , Antibacterianos/farmacologia , Fenômenos Magnéticos , Água , Zinco
9.
Ecotoxicol Environ Saf ; 226: 112826, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34592521

RESUMO

Levofloxacin antibiotic is frequently being detected in the environment and regarded as an emerging contaminant. The present study was focused on the green synthesis of magnetite (Fe3O4 - gINPs) nanoparticles from Moringa olifera and its efficiency for removal of levofloxacin from aqueous solution. The adsorbent magnetite nanoparticles (Fe3O4) were prepared by green synthesis using Moringa olifera and coprecipitation method. Characterizations analyses of both chemically and green synthesized nanoparticles were performed by SEM, XRD, and FTIR. The average crystallite size of gINPs was 14.34 nm and chemically synthesized was 18.93 nm. The performance of the synthesized product was evaluated by adsorption capacity and removal efficiency. The parameters considered included adsorbent (gINPs) dosage, initial concentration of adsorbate, pH, contact time, and temperature. The obtained data were fitted to kinetic and isotherm models to determine the mechanism. Adsorption batch experiments were conducted to determine the reaction mechanism by studying kinetics while fitting isotherm models for samples analyzed using HPLC at 280 nm. Results showed that 86.15% removal efficiency of 4 mg L-1 levofloxacin was achieved by 100 mg L-1 gINPs in 24 h contact time when all other parameters (pH 7, temperature 25 °C) were kept constant. The maximum adsorption capacity achieved at equilibrium was 22.47 mg/g. Further, it was identified as a pseudo-second-order model with R2 = 0.965 for adsorption kinetics while isotherm data better fitted to the Freundlich model compared to Langmuir isotherm with R2 = 0.994. The potential pathway determined for levofloxacin removal was chemisorption with minor diffusion, multilayer, spontaneous and exothermic processes on the gINPs (Fe3O4). Reusability experiments were conducted in four cycles and removal efficiency varied from 85.35% to 80.47%, indicating very high potential of the adsorbent for re-use.


Assuntos
Nanopartículas de Magnetita , Moringa , Poluentes Químicos da Água , Purificação da Água , Adsorção , Óxido Ferroso-Férrico , Concentração de Íons de Hidrogênio , Cinética , Levofloxacino , Poluentes Químicos da Água/análise
10.
J Environ Manage ; 299: 113648, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34479148

RESUMO

Biodegradation is the most economical and efficient process for remediating polycyclic aromatic hydrocarbons (PAHs) such as naphthalene (Nap). Soil composition is pivotal in controlling PAH migration and transformation. Iron minerals such as siderite and magnetite are the primary components of soil and sediment and play key roles in organic pollutant biodegradation. However, it is unclear whether siderite and magnetite promote or inhibit Nap biodegradation. The effects of siderite and magnetite on Nap biodegradation were investigated through batch experiments in this study. The results indicated that siderite increased Nap biodegradation efficiency by 7.87%, whereas magnetite inhibited Nap biodegradation efficiency by 3.54%. In the presence of siderite, Nap-degrading bacteria with acid-producing effects promoted siderite dissolution via metabolic activity, resulting in an increased Fe (II) concentration in solution which accelerated the iron reduction process and promoted Nap biodegradation. In addition, the presence of iron minerals altered the genus-level community structure. Anaerobic sulfate-reducing bacteria such as Desulfosporosinus occurred in the presence of siderite, indicating that sulfate reduction occurred in advance under the influence of siderite. In the presence of magnetite, Fe (III) in iron minerals were converted to Fe (II), and under the mediation of microorganisms, Fe (II) combined with carbonate to form secondary minerals (e.g., siderite). Secondary minerals were attached to the surface of magnetite, which inhibited magnetite dissolution and reduced the efficiency of Fe (III) utilization by microorganisms. Furthermore, as the reaction proceeds, acid-producing microorganisms promoted magnetite further dissolution, resulting in a longer duration of the Fe (III) reduction process. Bacteria utilizing sulfuric acid as the terminal electron acceptor consumed organic matter more rapidly than those using iron as the terminal electron acceptor. Therefore, magnetite inhibited Nap degradation. These observations enhance our understanding of the interaction mechanisms of iron minerals, organic pollutants, and degrading bacteria during the biodegradation process.


Assuntos
Carbonatos , Óxido Ferroso-Férrico , Biodegradação Ambiental , Compostos Férricos , Minerais , Naftalenos , Oxirredução
11.
Int J Nanomedicine ; 16: 6129-6140, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34511910

RESUMO

Purpose: With the development of nanomedicine, microwave ablation enhanced by multifunctional nanoplatforms has been widely studied for synergistic cancer therapy. Though scientists have got a lot of significant achievements in this field, the detailed molecular mechanisms and potential targets of microwave ablation enhanced by multifunctional nanoplatforms still need further exploration. In this study, we found that a kind of magnetite Fe3O4 nanoparticles (Fe3O4 NPs) could induce severe endoplasmic reticulum stress and activate cancer apoptosis under the irradiation of mild microwave. Methods: In this study, plenty of studies including cell immunofluorescence, mitochondrial membrane potential, electron microscopy, atomic force microscopy and microwave ablation in vivo were conducted to explore the molecular mechanisms and potential targets of microwave ablation enhanced by the Fe3O4 NPs. Results: The IRE1-ASK1-JNK pathway was strongly activated in A375 cells treated with both Fe3O4 NPs and mild microwave. The endoplasmic reticulum of the A375 cells was significantly dilated and exhibited ballooning degeneration. By investigating the mitochondrial membrane potential (ΔΨm), we found that the mitochondria of cancer cells had been significantly damaged under microwave treatment coupled with Fe3O4 NPs. In addition, melanoma of B16F10-bearing mice had also been effectively inhibited after being treated with Fe3O4 NPs and microwave. Conclusion: In this study, we found that a kind of magnetite Fe3O4 nanoparticles could induce severe ER stress and activate cancer apoptosis under mild microwave irradiation. Apparent apoptosis had been observed in the A375 cells under a scanning electron microscope and transmission electron microscope. Moreover, melanoma had also been inhibited effectively in vivo. As a result, the endoplasmic reticulum stress is a promising target with clinical potential in nanomedicine and cancer therapy.


Assuntos
Nanopartículas de Magnetita , Neoplasias , Animais , Apoptose , Linhagem Celular Tumoral , Estresse do Retículo Endoplasmático , Óxido Ferroso-Férrico , Sistema de Sinalização das MAP Quinases , Camundongos , Micro-Ondas , Neoplasias/tratamento farmacológico
12.
Environ Sci Process Impacts ; 23(10): 1531-1541, 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34515719

RESUMO

Abiotic reduction of nitrite (NO2-) by Fe(II) species (i.e., chemodenitrification) has been demonstrated in a variety of natural environments and laboratory studies, and is a potentially significant source of atmospheric nitrous oxide (N2O) emissions. It is, however, unclear how chemodenitrification rates and N2O yields vary among heterogeneous Fe(II) species under similar conditions and whether abiotic reduction competes with biological NO2- reduction. Here, we measured rates of NO2- reduction and extents of N2O production by several Fe(II) species under consistent, environmentally relevant conditions (i.e., pH 7.0, bicarbonate buffer, and 0.1 mM NO2-). Nitrite reduction rates varied significantly among the heterogeneous Fe(II) species with half-lives (t1/2) ranging from as low as an hour to over two weeks following the trend of goethite/Fe(II) ∼ hematite/Fe(II) ∼ magnetites > maghemite/Fe(II) > sediment/Fe(II). Interestingly, we observed no clear trend of increasing NO2- reduction rates with higher magnetite stoichiometry (x = Fe2+/Fe3+). Nitrogen recovery as N2O also varied significantly among the Fe species ranging from 21% to 100% recovery. We further probed both chemodenitrification and biological denitrification in the absence and presence of added aqueous Fe(II) with a sediment collected from the floodplain of an agricultural watershed. While abiotic NO2- reduction by the sediment + Fe(II) was much slower than the laboratory Fe(II) species, we found near complete mass N balance during chemodenitrification, as well as evidence for both abiotic and biological NO2- reduction potentially occurring in the sediment under anoxic conditions. Our results suggest that in redox active sediments and soils both chemodenitrification and biological denitrification are likely to occur simultaneously, and that agricultural watersheds may be significant sources of N2O emissions.


Assuntos
Desnitrificação , Nitritos , Óxido Ferroso-Férrico , Nitrogênio , Óxido Nitroso
13.
Nat Commun ; 12(1): 5243, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34475406

RESUMO

Peroxisome, a special cytoplasmic organelle, possesses one or more kinds of oxidases for hydrogen peroxide (H2O2) production and catalase for H2O2 degradation, which serves as an intracellular H2O2 regulator to degrade toxic peroxides to water. Inspired by this biochemical pathway, we demonstrate the reactive oxygen species (ROS) induced tumor therapy by integrating lactate oxidase (LOx) and catalase (CAT) into Fe3O4 nanoparticle/indocyanine green (ICG) co-loaded hybrid nanogels (designated as FIGs-LC). Based on the O2 redistribution and H2O2 activation by cascading LOx and CAT catalytic metabolic regulation, hydroxyl radical (·OH) and singlet oxygen (1O2) production can be modulated for glutathione (GSH)-activated chemodynamic therapy (CDT) and NIR-triggered photodynamic therapy (PDT), by manipulating the ratio of LOx and CAT to catalyze endogenous lactate to produce H2O2 and further cascade decomposing H2O2 into O2. The regulation reactions of FIGs-LC significantly elevate the intracellular ROS level and cause fatal damage to cancer cells inducing the effective inhibition of tumor growth. Such enzyme complex loaded hybrid nanogel present potential for biomedical ROS regulation, especially for the tumors with different redox state, size, and subcutaneous depth.


Assuntos
Antineoplásicos/farmacologia , Nanogéis/química , Peroxissomos/enzimologia , Fotoquimioterapia/métodos , Animais , Antineoplásicos/química , Catalase/química , Catalase/metabolismo , Catálise , Linhagem Celular Tumoral , Óxido Ferroso-Férrico/química , Glutationa/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Verde de Indocianina/química , Camundongos , Oxigenases de Função Mista/química , Oxigenases de Função Mista/metabolismo , Nanopartículas/química , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Oxigênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Microambiente Tumoral/efeitos dos fármacos
14.
ACS Appl Mater Interfaces ; 13(33): 39905-39914, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34374514

RESUMO

The lack of functional groups or binding sites largely hindered the broad application of microporous organic networks (MONs). Herein, we report the fabrication of the sulfonate group-enriched magnetic MON composite (MMON-SO3H@SO3Na) via the combination of the sulfonic acid group containing the monomer and thiol-yne click postmodification for efficient magnetic solid-phase extraction (MSPE) of benzimidazole fungicides (BZDs) from complex sample matrices. The well-defined core-shell-structured MMON-SO3H@SO3Na was obtained and served as an advanced adsorbent for MSPE for concentrating and monitoring trace BZDs. The MMON-SO3H@SO3Na with numerous sulfonate groups provides plenty of ion-exchange, hydrogen-bonding, and π-π sites, leading to the favorable affinity to BZDs via multiple interaction mechanisms. The MMON-SO3H@SO3Na-based MSPE-high-performance liquid chromatography method afforded a wide linear range, low limits of detection, large enrichment factors, good precisions, and reusability for BZDs. Trace BZDs in complex vegetables and fruit samples were successfully detected by the established method. The MMON-SO3H@SO3Na also exhibited good selectivity toward multiple types of polar contaminants containing hydrogen-bonding sites and aromatic structures. This work provided a new postsynthesis strategy for constructing novel and multifunctioned magnetic MONs for preconcentration of trace analytes in a complex matrix.


Assuntos
Alcanossulfonatos/síntese química , Alcinos/química , Benzimidazóis/isolamento & purificação , Análise de Alimentos/métodos , Fungicidas Industriais/isolamento & purificação , Compostos de Sulfidrila/química , Cromatografia Líquida de Alta Pressão/métodos , Química Click , Óxido Ferroso-Férrico/química , Frutas/química , Limite de Detecção , Magnetismo/métodos , Microesferas , Porosidade , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Verduras/química
15.
Bioresour Technol ; 341: 125783, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34418842

RESUMO

In this study, the effect of magnetite amendment on anaerobic digestion was investigated at three increasing salinity levels (0.5%, 1% and 2% NaCl). The amendment of magnetite enhanced the methane yield by 36.3%, 33.3% and 16.5% at low salinity (0.5% NaCl) and high salinity (1% and 2% NaCl), respectively. Meanwhile, a larger proportion of granules was obtained in the magnetite amended reactor (48.05% vs 33.16% at the end of operation). Microbial analysis suggested magnetite could induce more methanogenesis partnerships between hydrogenotrophic methanogens and syntrophic bacteria. Methanosaeta and Methanocorpusculum were the alternating dominant methanogens at low salinity and high salinity. While Streptococcus and Mesotoga were two prevalent bacteria that showed totally different transition tendency in two reactors. Additionally, the supplement of magnetite could relieve the suppression of methanogenesis-related gene expression caused by salinity, thus facilitated the higher methane production.


Assuntos
Microbiota , Águas Residuárias , Anaerobiose , Biomassa , Reatores Biológicos , Óxido Ferroso-Férrico , Metano
16.
Br J Radiol ; 94(1125): 20210430, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415199

RESUMO

OBJECTIVES: To assess the feasibility of a rapid, focused ferumoxytol-enhanced MR angiography (f-FEMRA) protocol in patients with claustrophobia. METHODS: In this retrospective study, 13 patients with claustrophobia expressed reluctance to undergo conventional MR angiography, but agreed to a trial of up to 10 min in the scanner bore and underwent f-FEMRA. Thirteen matched control patients who underwent gadolinium-enhanced MR angiography (GEMRA) were identified for comparison of diagnostic image quality. For f-FEMRA, the time from localizer image acquisition to completion of the angiographic acquisition was measured. Two radiologists independently scored images on both f-FEMRA and GEMRA for arterial and venous image quality, motion artefact and diagnostic confidence using a 5-point scale, five being best. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the aorta and IVC were measured. The Wilcoxon rank-sum test, one-way ANOVA with Tukey correction and two-tailed t tests were utilized for statistical analyses. RESULTS: All scans were diagnostic and assessed with high confidence (scores ≥ 4). Average scan time for f-FEMRA was 6.27 min (range 3.56 to 10.12 min), with no significant difference between f-FEMRA and GEMRA in diagnostic confidence (4.86 ± 0.24 vs 4.69 ± 0.25, p = 0.13), arterial image quality (4.62 ± 0.57 vs 4.65 ± 0.49, p = 0.78) and motion artefact score (4.58 ± 0.49 vs 4.58 ± 0.28, p > 0.99). f-FEMRA scored significantly better for venous image quality than GEMRA (4.62 ± 0.42 vs 4.19 ± 0.56, p = 0.04). CNR in the IVC was significantly higher for steady-state f-FEMRA than GEMRA regardless of the enhancement phase (p < 0.05). CONCLUSIONS: Comprehensive vascular MR imaging of the thorax, abdomen and pelvis can be completed in as little as 5 min within the magnet bore using f-FEMRA, facilitating acceptance by patients with claustrophobia and streamlining workflow. ADVANCES IN KNOWLEDGE: A focused approach to vascular imaging with ferumoxytol can be performed in patients with claustrophobia, limiting time in the magnet bore to 10 min or less, while acquiring fully diagnostic images of the thorax, abdomen and pelvis.


Assuntos
Meios de Contraste , Óxido Ferroso-Férrico , Aumento da Imagem/métodos , Angiografia por Ressonância Magnética/métodos , Angiografia por Ressonância Magnética/psicologia , Transtornos Fóbicos/psicologia , Estudos de Coortes , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Tempo
17.
Adv Biol (Weinh) ; 5(9): e2101017, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34296829

RESUMO

Recently, the photosynthetic Rhodospirillum rubrum has been endowed with the ability of magnetosome biosynthesis by transfer and expression of biosynthetic gene clusters from the magnetotactic bacterium Magnetospirillum gryphiswaldense. However, the growth conditions for efficient magnetite biomineralization in the synthetic R. rubrum "magneticum", as well as the particles themselves (i.e., structure and composition), have so far not been fully characterized. In this study, different cultivation strategies, particularly the influence of temperature and light intensity, are systematically investigated to achieve optimal magnetosome biosynthesis. Reduced temperatures ≤16 °C and gradual increase in light intensities favor magnetite biomineralization at high rates, suggesting that magnetosome formation might utilize cellular processes, cofactors, and/or pathways that are linked to photosynthetic growth. Magnetosome yields of up to 13.6 mg magnetite per liter cell culture are obtained upon photoheterotrophic large-scale cultivation. Furthermore, it is shown that even more complex, i.e., oligomeric, catalytically active functional moieties like enzyme proteins can be efficiently expressed on the magnetosome surface, thereby enabling the in vivo functionalization by genetic engineering. In summary, it is demonstrated that the synthetic R. rubrum "magneticum" is a suitable host for high-yield magnetosome biosynthesis and the sustainable production of genetically engineered, bioconjugated magnetosomes.


Assuntos
Magnetossomos , Magnetospirillum , Rhodospirillum rubrum , Óxido Ferroso-Férrico , Magnetospirillum/genética , Rhodospirillum rubrum/genética
18.
ACS Appl Mater Interfaces ; 13(30): 36157-36170, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34296851

RESUMO

Magnetic field-induced synthesis and biocatalysis of magnetic materials have inspired great interest due to the flexible controllability of morphologies and unique magnetoelectrical properties. However, the interaction of the magnetic field and the reaction kinetics during the synthesis of magnetic nanochains has not been revealed. The collective motions in fluids and the multifunctional enhancements for bioreaction of 3D magnetic-controlled nanochains have not been systematically researched. Here, an integrated 3D magnetic control method was reported for the synthesis, collective motion, and multifunctional bioreaction enhancement of peasecod-like nanochains. The interactions of magnetic field and reaction kinetics were rationally controlled to synthesize magnetic nanochains of different morphologies. Collective motions of nanochains under alternating magnetic fields were studied to provide insights into the disturbance on confined fluids. Three mechanisms of reaction enhancement of nanostir, magnetic agent, and nanocatalyst were achieved simultaneously via 3D magnetic-controlled nanochains using a glucose oxidase-horseradish peroxidase multi-enzyme system. The peasecod-like nanochain also exhibited excellent reaction enhancement in cell-free protein synthesis reaction, which is desired for effective high-throughput screening. The integrated 3D magnetic control method through the whole process from fabrication to applications of magnetic nanomaterials could be extended to multifunctional biocatalysis and multi-task biomedicine.


Assuntos
Óxido Ferroso-Férrico/química , Nanopartículas de Magnetita/química , Movimento (Física) , Armoracia/enzimologia , Óxido Ferroso-Férrico/síntese química , Glucose Oxidase/química , Proteínas de Fluorescência Verde/biossíntese , Peroxidase do Rábano Silvestre/química , Cinética , Campos Magnéticos , Biossíntese de Proteínas/efeitos dos fármacos , Dióxido de Silício/química
19.
Bioresour Technol ; 337: 125470, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34320750

RESUMO

Low temperature is adverse to anaerobic ammonium oxidation (anammox) reaction while proper Fe addition can enhance anammox performance. Therefore, batch assays were conducted to investigate the potential effects of magnetite (100 µm, 20 µm and 200 nm) on anammox performance which were achieved from the reactor operated at 10-25 °C. After 3 runs, the results indicated that nano-scale magnetite improved the nitrogen elimination significantly. The specific anammox activity (SAA) of the group with nano-magnetite amendments was greater than the other groups after 3 runs (13.5, 12.9, 14.3, 15.4 and 15.7 mgTN/(gVSS·h)), reaching 18.0 mgTN/(gVSS·h). The distribution of magnetite in the granules were then analyzed using X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). The results indicated that nano-magnetite was more feasible to attached to the surface of the granules which might accelerate the release of Fe(II) or Fe(III) to enhance anammox performance.


Assuntos
Compostos de Amônio , Reatores Biológicos , Anaerobiose , Compostos Férricos , Óxido Ferroso-Férrico , Nitrogênio , Oxirredução , Esgotos
20.
PLoS One ; 16(7): e0251744, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34197471

RESUMO

The free convective hybrid nanofluid (Fe3O4+MWCNT/H2O) magnetized non-Darcy flow over a porous cylinder is examined by considering the effects constant heat source and uniform ambient magnetic field. The developed coupled PDEs (partial differential equations) are numerically solved using the innovative computational technique of control volume finite element method (CVFEM). The impact of increasing strength of medium porousness and Lorentz forces on the hybrid nanofluid flow are presented through contour plots. The variation of the average Nusselt number (Nuave) with the growing medium porosity, buoyancy forces, radiation parameter, and the magnetic field strength is presented through 3-D plots. It is concluded that the enhancing medium porosity, buoyancy forces and radiation parameter augmented the free convective thermal energy flow. The rising magnetic field rises the temperature of the inner wall more drastically at a smaller Darcy number. An analytical expression for Nusselt number (Nuave) is obtained which shows its functional dependence on the pertinent physical parameters. The augmenting Lorentz forces due to the higher estimations of Hartmann retard the hybrid nanoliquid flow and hence enhance the conduction.


Assuntos
Algoritmos , Óxido Ferroso-Férrico/química , Nanoestruturas/química , Nanotubos de Carbono/química , Água/química , Análise de Elementos Finitos , Campos Magnéticos , Porosidade , Temperatura
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