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1.
J Environ Manage ; 274: 111208, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32814213

RESUMO

Photodegradation of toxic pollutants is a promising approach to deal with wastewater management. In this regard, MoS2/g-C3N4 (MSC) derived composites with varying weight-ratios were prepared via fast (30 min) one step microwave-assisted method. The materials were characterized by XRD, XPS, EDS, FESEM and HRTEM to validate their flower-like and sheet-like morphologies. The PL and UV-vis DRS spectra exhibited low recombination-rate and band-gap (1.7 eV), which is appropriate for an effective visible-light degradation. Photocatalytic performance of the catalysts was analyzed by investigating the degradation of methylene blue (MB) as well as pesticide fipronil. Best results were obtained by 5:1 MSC (98.7% degradation efficacy; rate constant 0.0261 min-1) in 80 min under the sunlight. The effects of solution pH, catalyst-dose, scavengers and illumination-area were also explored. The catalyst was reusable as confirmed by degradation studies (~82% efficiency) even after 5-cycles. The photocatalytic treatment of real industrial-wastewater was also conducted. The TOC and COD analysis validated that the treatment by as-prepared catalyst is more proficient for effluent-treatment than the industrial physico-chemical treatments. Electrochemical degradation of MB was also investigated using the glassy carbon electrode modified with different MSC-ratios. The electrode modified with 5:1 MSC at pH 7 manifested the maximum peak current. The plausible mechanisms for photocatalytic and electrochemical degradations were proposed, which suggested the remarkable potential the prepared nanocomposites for wastewater treatment.


Assuntos
Poluentes Ambientais , Molibdênio , Catálise , Luz , Fotólise
2.
Int J Nanomedicine ; 15: 5517-5526, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801703

RESUMO

Introduction: Hypertension is a major health problem worldwide and is typically treated using oral drugs. However, the frequency of oral administration may result in poor patient compliance, and reduced bioavailability owing to the first-pass effect can also prove problematic. Methods: In this study, we developed a new transdermal-drug-delivery system (TDDS) for the treatment of hypertension using atenolol (ATE) based on poly(acrylic acid) (PAA)-decorated three-dimensional (3D) flower-like MoS2 nanoparticles (PAA-MoS2 NPs) that respond to NIR laser irradiation. The PAA-modified MoS2 NPs were synthesized and characterized using attenuated total reflection Fourier-transform infrared spectroscopy, X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and the sedimentation equilibrium method. The drug-loading efficiency and photothermal conversion effect were also explored. Results: The results showed that the colloidally stable PAA-MoS2 NPs exhibited a high drug-loading capacity of 54.99% and high photothermal conversion ability. Further, the capacity of the PAA-MoS2 NPs for controlled release was explored using in vitro drug-release and skin-penetration studies. The drug-release percentage was 44.72 ± 1.04%, and skin penetration was enhanced by a factor of 1.85 in the laser-stimulated group. Sustained and controlled release by the developed TDDS were observed with laser stimulation. Moreover, in vivo erythema index analysis verified that the PAA-MoS2 NPs did not cause skin irritation. Discussion: Our findings demonstrate that PAA-MoS2 NPs can be used as a new carrier for transdermal drug delivery for the first time.


Assuntos
Anti-Hipertensivos/administração & dosagem , Atenolol/administração & dosagem , Dissulfetos/química , Sistemas de Liberação de Medicamentos/métodos , Molibdênio/química , Nanopartículas/administração & dosagem , Resinas Acrílicas/química , Administração Cutânea , Animais , Anti-Hipertensivos/farmacocinética , Atenolol/efeitos adversos , Atenolol/farmacocinética , Sistemas de Liberação de Medicamentos/efeitos adversos , Liberação Controlada de Fármacos , Difusão Dinâmica da Luz , Eritema/induzido quimicamente , Humanos , Lasers , Masculino , Microscopia Eletrônica de Transmissão , Nanopartículas/química , Coelhos , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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.
Sci Total Environ ; 742: 140545, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629262

RESUMO

Despite growing applications of molybdenum(IV) sulfide (MoS2) nano- and microparticles in their capacity as lubricants, data available on their safety are scarce. In this study the effect of MoS2 nano- and microparticles after single intratracheal instillation in rats has been analyzed. MoS2 suspensions were administered at the dose of 1.5 or 5 mg MoS2/kg body weight. The analysis after 24 h and 7 days included: blood biochemical parameters, hematological parameters, bronchoalveolar lavage fluid (BALF) parameters with selected cytokines, a comet assay and histopathological examination. In the BALF cells isolated from animals exposed to both forms, numerous macrophages loaded with particles were observed. The hematological and biochemical parameters analyzed 24 h or 7 days after the exposure to both forms did not show any biologically meaningful changes. Comet assay results showed no genotoxic effect. The histopathological analysis of the lungs revealed inflammatory changes in the respiratory system of the treated animals, slightly stronger for the microsized form. The deposits of particles observed in the lung tissue up to 7 days after the instillation indicate their easy penetration through the epithelium and prolonged clearance. Concluding, no meaningful acute systemic effects were observed, however some pathological changes were noted in the lung tissue.


Assuntos
Pulmão , Molibdênio , Animais , Líquido da Lavagem Broncoalveolar , Dissulfetos , Contagem de Leucócitos , Ratos
5.
Food Chem ; 333: 127515, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32683260

RESUMO

The nutritional and commercial value of the sweet cherry provides it a great economic importance in Italy. The aim of this study was to characterize 35 sweet cherry cultivars and one of sour cherry, by analyzing values of different pomological and nutraceutical traits, identifying cultivars with antioxidant activity and total anthocyanins content closest to those present in literature for Ferrovia (largely diffused in Italy). To this goal, a multivariate metric index through the Soft Independent Modeling of Class Analogy analyzing an artificial dataset and testing a real one, two hierarchical clustering and a principal component analysis, were performed. The multivariate analyses result simultaneously investigated all the variables highlighting cvs. Sylvia, Graffione nero Col di Mosso, Ferrovia, Mora della Punta, Bianchetta Nuchis and Sandra to be more similar to literature data of Ferrovia. This matrix index was a useful tool, to select the most commercial promising varieties.


Assuntos
Algoritmos , Prunus avium/classificação , Antocianinas/análise , Antioxidantes/química , Análise por Conglomerados , Frutas/química , Frutas/metabolismo , Concentração de Íons de Hidrogênio , Itália , Molibdênio/química , Fenóis/análise , Extratos Vegetais/química , Análise de Componente Principal , Prunus avium/química , Prunus avium/metabolismo , Compostos de Tungstênio/química
6.
Chemosphere ; 259: 127465, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32623202

RESUMO

The direct shedding of piperazine rings is critical for the degradation of antibiotic persistent organic pollutants. In this work, nitrogen-deficient g-C3N4 loaded with polyoxometalates porous photocatalysts with P-N heterojunctions were carried out through the formation of chemical bonds between the nitrogen-deficient C+ in g-C3Nx and the bridging oxygen in polyoxometalates (POMs), including phosphomolybdic acid (PMA), phosphotungstic acid (PTA) and silicotungstic acid (STA). The adsorption and photocatalysis experiments confirm the ability of the g-C3Nx/POMs nanosheets to efficiently remove ciprofloxacin via the synergistic effects of adsorption and photo-catalysis. Approximately, g-C3Nx/POMs-30 exhibits the optimal degradation ability, and the degradation rates of g-C3Nx/PMA-30, g-C3Nx/PTA-30 and g-C3Nx/STA-30 could respectively reach 93.1%, 97.4% and 95.6% within only 5 min under visible light. The free radical scavenging experiment and ESR free radical capture experiments confirm that ·OH and ·O2- are free radicals that effectively degrade CIP. According to the results of the LC-MS analysis, the intermediates produced after CIP degradation and the efficient degradation pathway are proposed. The direct shedding of piperazine rings in the decarboxylation and defluorination process leads to the most efficient degradation of CIP into the small molecules.


Assuntos
Antibacterianos/química , Ciprofloxacino/química , Processos Fotoquímicos , Adsorção , Catálise , Luz , Molibdênio , Nanoestruturas/química , Nitrogênio , Ácidos Fosfóricos , Porosidade , Silicatos , Compostos de Tungstênio
7.
Environ Sci Pollut Res Int ; 27(32): 40495-40503, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32666452

RESUMO

The Ce-doped different MoO3 [conventional molybdenum oxide (con-MoO3) or nano molybdenum oxide (nano-MoO3) and synthetic molybdenum oxide (syn-MoO3)] modification of ZSM-5 catalyst synthesized by different preparation methods (the combination of grinding and ion-exchange method and the combination of impregnation and ion-exchange method) was studied on selective catalytic reduction (SCR) of NOx with NH3. The results demonstrated that the SCR performance of the prepared Ce-doped syn-MoO3 modification of ZSM-5 catalyst [Ce(0.9%)-syn-MoO3(6%)/ZSM-5] by the combination of impregnation and ion-exchange method was better than Ce-doped con-MoO3 modification of ZSM-5 [Ce(0.9%)-con-MoO3(6%)/ZSM-5] and Ce-doped nano-MoO3 modification of ZSM-5 [Ce(0.9%)-nano-MoO3(6%)/ZSM-5] via the combination of grinding and ion-exchange method, especially when the temperature window is 200-350 °C. That is because it is easy to form Mo-O-Al by the smaller sized MoO3 more easily interacting well with Brønsted acid under calcining temperature, which results in the decrease of Brønsted acid sites in the catalyst. Combing with the binding energy of Mo for all the catalysts, the combination of Mo and Al (Mo-O-Al) altered the chemical environment around the Mo species. Furthermore, Ce(0.9%)-syn-MoO3(6%)/ZSM-5 exhibited excellent sulfur resistance.


Assuntos
Amônia , Óxido Nítrico , Catálise , Molibdênio , Oxirredução
8.
Int J Nanomedicine ; 15: 3291-3302, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32494130

RESUMO

Background: Inhaled nanoparticles can cross pulmonary air-blood barrier into circulation and cause vascular endothelial injury and progression of cardiovascular disease. However, the molecular mechanism underlying the vascular toxicity of copper oxide nanoparticles (CuONPs) remains unclear. We have recently demonstrated that the release of copper ions and the accumulation of superoxide anions contributed to CuONPs-induced cell death in human umbilical vein endothelial cells (HUVECs). Herein, we further demonstrate the mechanism underlying copper ions-induced cell death in HUVECs. Methods and Results: CuONPs were suspended in culture medium and vigorously vortexed for several seconds before exposure. After treatment with CuONPs, HUVECs were collected, and cell function assays were conducted to elucidate cellular processes including cell viability, oxidative stress, DNA damage and cell signaling pathways. We demonstrated that CuONPs uptake induced DNA damage in HUVECs as evidenced by γH2AX foci formation and increased phosphorylation levels of ATR, ATM, p53 and H2AX. Meanwhile, we showed that CuONPs exposure induced oxidative stress, indicated by the increase of cellular levels of superoxide anions, the upregulation of protein levels of heme oxygenase-1 (HO-1) and glutamate-cysteine ligase modifier subunit (GCLM), the elevation of the levels of malondialdehyde (MDA), but the reduction of glutathione to glutathione disulfide ratio. We also found that antioxidant N-acetyl-L-cysteine (NAC) could ameliorate CuONPs-induced oxidative stress and cell death. Interestingly, we demonstrated that p38 mitogen-activated protein kinase (MAPK) signaling pathway was activated in CuONPs-treated HUVECs, while p38α MAPK knockdown by siRNA significantly rescued HUVECs from CuONPs-induced DNA damage and cell death. Importantly, we showed that copper ions chelator tetrathiomolybdate (TTM) could alleviate CuONPs-induced oxidative stress, DNA damage, p38 MAPK pathway activation and cell death in HUVECs. Conclusion: We demonstrated that CuONPs induced oxidative DNA damage and cell death via copper ions-mediated p38 MAPK activation in HUVECs, suggesting that the release of copper ions was the upstream activator for CuONPs-induced vascular endothelial toxicity, and the copper ions chelator TTM can alleviate CuONPs-associated cardiovascular disease.


Assuntos
Cobre/toxicidade , Dano ao DNA , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/patologia , Nanopartículas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Morte Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Modelos Biológicos , Molibdênio/química , Nanopartículas/ultraestrutura
9.
Artigo em Inglês | MEDLINE | ID: mdl-32485845

RESUMO

Nontuberculous mycobacteria (NTM) are environmental bacteria that may cause chronic lung disease. Environmental factors that favor NTM growth likely increase the risk of NTM exposure within specific environments. We aimed to identify water-quality constituents (Al, As, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Mo, Ni, K, Se, Na, Zn, and pH) associated with NTM disease across Colorado watersheds. We conducted a geospatial, ecological study, associating data from patients with NTM disease treated at National Jewish Health and water-quality data from the Water Quality Portal. Water-quality constituents associated with disease risk were identified using generalized linear models with Poisson-distributed discrete responses. We observed a highly robust association between molybdenum (Mo) in the source water and disease risk. For every 1- unit increase in the log concentration of molybdenum in the source water, disease risk increased by 17.0%. We also observed a statistically significant association between calcium (Ca) in the source water and disease risk. The risk of NTM varied by watershed and was associated with watershed-specific water-quality constituents. These findings may inform mitigation strategies to decrease the overall risk of exposure.


Assuntos
Molibdênio , Infecções por Mycobacterium não Tuberculosas , Poluição da Água/estatística & dados numéricos , Qualidade da Água , Colorado , Humanos , Micobactérias não Tuberculosas
10.
BMC Bioinformatics ; 21(1): 162, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32349661

RESUMO

BACKGROUND: The reconstruction of metabolic networks and the three-dimensional coverage of protein structures have reached the genome-scale in the widely studied Escherichia coli K-12 MG1655 strain. The combination of the two leads to the formation of a structural systems biology framework, which we have used to analyze differences between the reactive oxygen species (ROS) sensitivity of the proteomes of sequenced strains of E. coli. As proteins are one of the main targets of oxidative damage, understanding how the genetic changes of different strains of a species relates to its oxidative environment can reveal hypotheses as to why these variations arise and suggest directions of future experimental work. RESULTS: Creating a reference structural proteome for E. coli allows us to comprehensively map genetic changes in 1764 different strains to their locations on 4118 3D protein structures. We use metabolic modeling to predict basal ROS production levels (ROStype) for 695 of these strains, finding that strains with both higher and lower basal levels tend to enrich their proteomes with antioxidative properties, and speculate as to why that is. We computationally assess a strain's sensitivity to an oxidative environment, based on known chemical mechanisms of oxidative damage to protein groups, defined by their localization and functionality. Two general groups - metalloproteins and periplasmic proteins - show enrichment of their antioxidative properties between the 695 strains with a predicted ROStype as well as 116 strains with an assigned pathotype. Specifically, proteins that a) utilize a molybdenum ion as a cofactor and b) are involved in the biogenesis of fimbriae show intriguing protective properties to resist oxidative damage. Overall, these findings indicate that a strain's sensitivity to oxidative damage can be elucidated from the structural proteome, though future experimental work is needed to validate our model assumptions and findings. CONCLUSION: We thus demonstrate that structural systems biology enables a proteome-wide, computational assessment of changes to atomic-level physicochemical properties and of oxidative damage mechanisms for multiple strains in a species. This integrative approach opens new avenues to study adaptation to a particular environment based on physiological properties predicted from sequence alone.


Assuntos
Adaptação Fisiológica , Escherichia coli K12/fisiologia , Estresse Oxidativo , Proteoma/metabolismo , Antioxidantes/metabolismo , Proteínas de Escherichia coli/metabolismo , Fímbrias Bacterianas/metabolismo , Modelos Biológicos , Molibdênio/metabolismo , Óperon/genética , Oxirredução , Periplasma/metabolismo , Fenótipo , Espécies Reativas de Oxigênio/metabolismo
11.
Chemosphere ; 256: 127099, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32470733

RESUMO

Membrane fouling is an issue of concern due to the hydrophobic properties of polyethersulfone (PES) membrane when applied in water treatment. In this work, a facile hydrothermal method was utilized to synthesize hierarchical flower-like structured molybdenum disulfide nanosheets (HF-MoS2 NSs) that then incorporated into PES membranes as composite membranes. We characterized their permeability, the separation performance, the antifouling performance, and the antibacterial activity systematically. Results showed that composite membranes exhibited a better pure water flux (286 LMH/bar) at the HF-MoS2 NSs content of 0.4 wt%, which was 1.8 times higher than the control membrane. Also, composite PES membranes achieved 98.2% and 96.9% rejection of BSA and HA in comparison with the control PES membrane (87.3%, and 84.5%, respectively). Compare to the control PES membrane, the flux recovery ratio of the composite membrane increased from 69% to 88% for BSA fouling and increased from 84% to 93% for HA fouling. The retention rate for the organic dyes also improved slightly after HF-MoS2 NSs incorporation into the membrane. Additionally, the composite membranes exhibited a relatively high antibacterial activity against E. coli and B. subtilis with antibacterial rates of 67.8% and 82.5%, respectively. In conclusion, HF-MoS2 NSs incorporated composite membranes were shown to have outstanding filtration performance and could be a promising candidate for practical application in water filtration.


Assuntos
Nanoestruturas/química , Polímeros/química , Sulfonas/química , Purificação da Água/métodos , Dissulfetos/química , Escherichia coli , Filtração , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Molibdênio/química , Permeabilidade , Água/química
12.
J Environ Manage ; 268: 110610, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-32383643

RESUMO

Phosphorus (P) is one of the most restrictive essential elements to crop growth and development due to less availability in the soil system. Previous studies have reported the synergistic effects between molybdenum (Mo) and P fertilizer on P uptake in various crops. However, an induced long term effect of Mo on soil P dynamics in the rhizosphere and non-rhizosphere has not been reported yet in leguminous crops. In this study, a long term field experiment was conducted to explore the P transformation characteristics and bioavailability in Mo-deficient (-Mo) and Mo-enriched (+Mo) soil under leguminous (broad bean-soybean) cropping system. The results indicated that long-term Mo application increased the plant dry matter accumulation (14.23%-35.27%, for broad bean; 24.40%-37.46%, for soybean) from March-September. In rhizosphere soil, the percent decrease in pH (8.10%) under +Mo treatment of the soybean crop was recorded more during September as compared to broad bean crop. Under Mo supply, H2O-Pi fraction increased up to 28.53% and 43.67% while for NaHCO3-Pi this increase was up to 5.61% and 11.98%, respectively in the rhizosphere soil of broad bean and soybean, whereas, residual-P exhibited the highest proportion of P fractions. Moreover, compared with -Mo, +Mo treatments significantly increased the soil acid phosphatase (broad bean = 17.43 µmol/d/g; soybean = 28.60 µmol/d/g), alkaline phosphatase (broad bean = 3.34 µmol/d/g; soybean 6.35 µmol/d/g) and phytase enzymes activities (broad bean = 2.45 µmol/min/g; soybean = 5.91 µmol/min/g), transcript abundance of phoN/phoC genes and microbial biomass P (MBP) in rhizosphere soil. In crux, the findings of this study suggest that long term Mo application enhanced P bioavailability through increased available P, MBP, P related enzymes activities and their genes expressions which may represent a strategy of Mo to encounter P deficiencies in the soil system.


Assuntos
Fabaceae , Solo , Molibdênio , Fósforo , Rizosfera , Microbiologia do Solo
13.
Ecotoxicol Environ Saf ; 200: 110772, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32464444

RESUMO

Recently two-dimensional nanomaterials, such as graphene and molybdenum disulfide (MoS2), have received much attention as adsorbent materials for the effective removal of organic contaminants. MoS2 is attracting attention, not only for its chemical-physical properties, but also for its wide availability in nature as a constituent of molybdenite. The aim of this investigation was to assess the effects of different MoS2 concentrations (5 × 10-1, 5 × 10-2 and 5 × 10-3 mg/ml) on the embryonated eggs of Gallus gallus domesticus, according to Beck method. We evaluated the toxic effect of the MoS2 powder purchased at Sigma-Aldrich indicated as "received" and MoS2 powder treated via mechanical milling indicated as "ball mille". Subsequently, the embryos were sacrificed at different times of embryonic development (11th, 15th and 19th day after incubation) in order to evaluate their embryotoxic and teratogenic effects. The alterations of the embryonic development were studied by morphological and immunohistochemical analysis of the tissues. The results obtained have shown the toxicity of both powders of MoS2 with a high percentage of deaths and growth delays. Moreover, the immunohistochemical analysis performed on several tissue sections showed a strong positivity to the anti-metallothionein1 antibody only for the erythrocytes.


Assuntos
Dissulfetos/química , Dissulfetos/toxicidade , Desenvolvimento Embrionário/efeitos dos fármacos , Molibdênio/química , Molibdênio/toxicidade , Nanopartículas/química , Nanopartículas/toxicidade , Animais , Embrião de Galinha , Relação Dose-Resposta a Droga , Grafite/química , Coração/efeitos dos fármacos , Coração/embriologia , Fígado/efeitos dos fármacos , Fígado/embriologia , Fígado/patologia , Pulmão/efeitos dos fármacos , Pulmão/embriologia , Pulmão/patologia , Tamanho da Partícula , Propriedades de Superfície
14.
Chemosphere ; 255: 126995, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32416394

RESUMO

In this paper, we present the preparation of MoS2-modified magnetic biochar (MoS2@MBC) as a novel adsorbent by a simple hydrothermal method. MoS2@MBC contains abundant S-containing functional groups that facilitate efficient Cd(II) removal from aqueous systems. We employed various characterization techniques to explore the morphology, surface area, and chemical composition of MoS2@MBC; these included Brunauer-Emmett-Teller analysis scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction,. The results indicated the successful decoration of the surface of MoS2@MBC with iron and MoS2, and a higher surface area of MoS2@MBC than that of unmodified biochar. Moreover, adsorption properties including thermodynamics and kinetics were investigated along with the effects of pH, humic acid, and ionic strength on the Cd(II) adsorption onto MoS2@MBC. The O-, C-, S-, and Fe-containing functional groups on the surface of MoS2@MBC led to an electrostatic attraction of Cd(II) and strong Cd-S complexation. The Langmuir and pseudo second-order models fitted best for the batch adsorption experiments results. The adsorption capacity of MoS2@MBC (139 mg g-1 on the basis of the Langmuir model) was 7.81 times higher than that of pristine biochar. The adsorption process was found to be pH-dependent. The experimental results indicated that MoS2@MBC is an effective adsorbent for removing Cd(II) from water solutions. Further, the adsorption process involved the complexation of Cd(II) with oxygen-based functional groups, ion exchange, electrostatic attraction, Cd(II)-π interactions, metal-sulfur complexation, and inner-surface complexation. This work provides new insights into the Cd(II) ions removal from water via adsorption. It also demonstrates that MoS2@MBC is an efficient and economic adsorbent to treat Cd(II)-contaminated water.


Assuntos
Adsorção , Cádmio/isolamento & purificação , Carvão Vegetal/química , Dissulfetos/química , Molibdênio/química , Purificação da Água/métodos , Cádmio/química , Cinética , Concentração Osmolar , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
15.
Int J Nanomedicine ; 15: 2971-2986, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32431496

RESUMO

Background: Due to their extraordinary physical and chemical properties, MoS2 nanosheets (MSNs) are becoming more widely used in nanomedicine. However, their influence on immune systems remains unclear. Materials and Methods: Two few-layered MSNs at sizes of 100-250 nm (S-MSNs) and 400-500 nm (L-MSNs) were used in this study. Bone marrow-derived dendritic cells (DCs) were exposed to both MSNs at different doses (0, 8, 16, 32, 64, 128 µg/mL) for 48 h and subjected to analyses of surface marker expression, cytokine secretion, lymphoid homing and in vivo T cell priming. Results: Different-sized MSNs of all doses did not affect the viability of DCs. The expression of CD40, CD80, CD86 and CCR7 was significantly higher on both S-MSN- and L-MSN-treated DCs at a dose of 128 µg/mL. As the dose of MSN increased, the secretion of IL-12p70 remained unchanged, the secretion of IL-1ß decreased, and the production of TNF-α increased. A significant increase in IL-6 was observed in the 128 µg/mL L-MSN-treated DCs. In particular, MSN treatment dramatically improved the ex vivo movement and in vivo homing ability of both the local resident and blood circulating DCs. Furthermore, the cytoskeleton rearrangement regulated by ROS elevation was responsible for the enhanced homing ability of the MSNs. More robust CD4+ and CD8+ T cell proliferation and activation (characterized by high expression of CD107a, CD69 and ICOS) was observed in mice vaccinated with MSN-treated DCs. Importantly, exposure to MSNs did not interrupt LPS-induced DC activation, homing and T cell priming. Conclusion: Few-layered MSNs ranging from 100 to 500 nm in size could play an immunostimulatory role in enhancing DC maturation, migration and T cell elicitation, making them a good candidate for vaccine adjuvants. Investigation of this study will not only expand the applications of MSNs and other new transition metal dichalcogenides (TMDCs) but also shed light on the in vivo immune-risk evaluation of MSN-based nanomaterials.


Assuntos
Diferenciação Celular , Movimento Celular , Células Dendríticas/citologia , Células Dendríticas/imunologia , Dissulfetos/farmacologia , Molibdênio/farmacologia , Nanopartículas/química , Linfócitos T/citologia , Linfócitos T/imunologia , Animais , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Citoesqueleto/efeitos dos fármacos , Citoesqueleto/metabolismo , Células Dendríticas/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Nanopartículas/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo , Linfócitos T/efeitos dos fármacos
16.
Artigo em Inglês | MEDLINE | ID: mdl-32464490

RESUMO

Soil phosphorus (P) occurs in pools of lower availability due to soil P fixation and therefore, it is a key constrain to crop production. Long term molybdenum-induced effects in wheat and rhizosphere/non-rhizosphere soil P dynamics have not yet been investigated. Here, a long term field experiment was conducted to explore these effects in wheat consisting of two treatments i.e. with molybdenum (+Mo) and without molybdenum (-Mo). The results revealed that molybdenum (Mo) supply increased plant biomass, grain yield, P uptake, preserved the configuration of chloroplast, stomata, and mesophyll tissue cells, suggesting the complementary effects of Mo on wheat yield and P accumulation. During the periods of vegetative growth, soil organic carbon, organic matter, and microbial biomass P were higher and tended to decrease in rhizosphere soil at maturity stage. In +Mo treatment, the most available P fractions [H2O-Pi (16.2-22.9 mg/kg and 4.24-7.57 mg/kg) and NaHCO3-Pi (130-149 mg/kg and 77.2-88 mg/kg)] were significantly increased in rhizosphere and non-rhizosphere soils, respectively. In addition, the +Mo treatment significantly increased the acid phosphatase activity and the expression of phoN/phoC, aphA, olpA/lppC gene transcripts in rhizosphere soil compared to -Mo. Our research findings suggested that Mo application has increased P availability not only through biochemical and chemical changes in rhizosphere but also through P assimilation and induced effects in the leaf ultra-structures. So, it might be a strategy of long term Mo fertilizer supply to overcome the P scarcity in plants and rhizosphere soil.


Assuntos
Molibdênio/farmacologia , Fósforo/metabolismo , Folhas de Planta/ultraestrutura , Rizosfera , Triticum/efeitos dos fármacos , Carbono , Solo , Triticum/metabolismo
17.
Proc Natl Acad Sci U S A ; 117(24): 13329-13338, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32461372

RESUMO

Two-dimensional (2D) molybdenum disulfide (MoS2) nanomaterials are an emerging class of biomaterials that are photoresponsive at near-infrared wavelengths (NIR). Here, we demonstrate the ability of 2D MoS2 to modulate cellular functions of human stem cells through photothermal mechanisms. The interaction of MoS2 and NIR stimulation of MoS2 with human stem cells is investigated using whole-transcriptome sequencing (RNA-seq). Global gene expression profile of stem cells reveals significant influence of MoS2 and NIR stimulation of MoS2 on integrins, cellular migration, and wound healing. The combination of MoS2 and NIR light may provide new approaches to regulate and direct these cellular functions for the purposes of regenerative medicine as well as cancer therapy.


Assuntos
Dissulfetos/efeitos da radiação , Células-Tronco Mesenquimais/efeitos da radiação , Molibdênio/efeitos da radiação , Nanoestruturas/efeitos da radiação , Adesão Celular/efeitos da radiação , Movimento Celular/efeitos da radiação , Sobrevivência Celular , Dissulfetos/química , Dissulfetos/metabolismo , Perfilação da Expressão Gênica , Humanos , Raios Infravermelhos , Integrinas/genética , Integrinas/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Molibdênio/química , Molibdênio/metabolismo , Nanoestruturas/química , Fármacos Fotossensibilizantes , Transdução de Sinais/efeitos da radiação
18.
Water Res ; 178: 115832, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32335368

RESUMO

Selenium pollution has become an increasingly serious global concern. Methane-fed selenate reduction has proven to be of great interest for the bioremediation of selenate-contaminated waters even with the coexistence of nitrate and dissolved oxygen. However, it is unclear if the common concurrent sulfate anion affects selenate removal. To address this question, we first introduced selenate (SeO42-) as the sole influent electron acceptor in a CH4-fed membrane biofilm reactor (CH4-MBfR); then we added different concentrations of sulfate (SO42-). The initial selenate removal efficiency (∼90%) was decreased by 50% in the presence of 15.6 µM of sulfate and completely inhibited after loading with 171.9 µM of sulfate. 16S rRNA gene sequencing showed that the selenate-reducing bacteria decreased after the addition of sulfate. Metagenomic sequencing showed that the abundance of genes encoding molybdenum (Mo)-dependent selenate reductase reduced by >50% when exposed to high concentrations of sulfate. Furthermore, the decrease in the total genes encoding all Mo-oxidoreductases was much greater than that of the genes encoding molybdate transporters, suggesting that the inhibition of selenate reduction by sulfate was most likely via the direct competition with molybdate for the transport system, leading to a lack of available Mo for Mo-dependent selenate reductases and thus reducing their activities. This result was confirmed by a batch test wherein the supplementation of molybdate mitigated the sulfate effect. Overall, this study shed light on the underlying mechanism of sulfate inhibition on selenate reduction and laid the foundation for applying the technology to practical wastewaters.


Assuntos
Molibdênio , Sulfatos , Oxirredutases , RNA Ribossômico 16S , Ácido Selênico
19.
Environ Sci Pollut Res Int ; 27(16): 20227-20234, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32239403

RESUMO

In this investigation, batch and column experiments were conducted to investigate the molybdenum (Mo) sorption and transport processes on a neutral-pH soil (Webster loam) and an acidic soil (Mahan sand) in Ca2+ and K+ background solutions. Batch results showed that the adsorption of Mo was strongly non-linear in both soils and amount of Mo sorbed in the acidic soil was larger than the neutral soil. The Freundlich distribution coefficients (Kf) and Langmuir sorption maxima (Smax) in Ca2+ background solution are larger than that in K+ solution, indicating greater Mo sorption in Ca2+ than in K+. Experimental breakthrough curves (BTCs) demonstrated that mobility of Mo was higher at neutral condition than that at acidic condition. A multi-reaction transport model (MRTM) formulation with two kinetic retention reactions (reversible and irreversible) well described Mo transport for Webster soil. However, MRTM model which accounts for equilibrium and kinetic sites is recommended for Mo transport in Mahan soil, reflecting different soil properties. Based on inverse modeling, the sorption forward rate coefficients (k1) obtained from Ca2+ in both soils are larger than that from K+, which consistent with batch experiment. Overall, MRTM model was capable of describing the Mo transport behavior under different geochemical conditions.


Assuntos
Poluentes do Solo/análise , Solo , Adsorção , Cinética , Molibdênio
20.
Nat Commun ; 11(1): 1912, 2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32313256

RESUMO

Metal-containing formate dehydrogenases (FDH) catalyse the reversible oxidation of formate to carbon dioxide at their molybdenum or tungsten active site. They display a diverse subunit and cofactor composition, but structural information on these enzymes is limited. Here we report the cryo-electron microscopic structures of the soluble Rhodobacter capsulatus FDH (RcFDH) as isolated and in the presence of reduced nicotinamide adenine dinucleotide (NADH). RcFDH assembles into a 360 kDa dimer of heterotetramers revealing a putative interconnection of electron pathway chains. In the presence of NADH, the RcFDH structure shows charging of cofactors, indicative of an increased electron load.


Assuntos
Microscopia Crioeletrônica/métodos , Formiato Desidrogenases/química , Rhodobacter capsulatus/metabolismo , Dióxido de Carbono/metabolismo , Catálise , Domínio Catalítico , Modelos Moleculares , Molibdênio/química , NAD/química , NAD/metabolismo , Oxirredução , Tungstênio
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