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1.
Trials ; 23(1): 19, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34991703

RESUMO

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to affect the globe. After 18 months of the SARS-CoV-2 emergence, clinicians have clearly defined a subgroup of patients with lasting, disabling symptoms. While big strides have been made in understanding the acute phase of SARS-CoV-2 infection, the pathophysiology of long COVID is still largely unknown, and evidence-based, effective treatments for this condition remain unavailable. OBJECTIVES: To evaluate the efficacy of 10 mg oral montelukast every 24 h versus placebo in improving quality of life associated with mild to moderate respiratory symptoms in patients with long COVID as measured with the COPD Assessment Test (CAT) questionnaire. The secondary objectives will evaluate the effect of montelukast versus placebo on improving exercise capacity, COVID-19 symptoms (asthenia, headache, mental confusion or brain fog, ageusia, and anosmia), oxygen desaturation during exertion, functional status, and mortality. METHODS AND ANALYSIS: Phase III, randomized, double-blind clinical trial. We will include 18- to 80-year-old patients with SARS-CoV-2 infection and mild to moderate respiratory symptoms lasting more than 4 weeks. Participants will be randomly allocated in a 1:1 ratio to the intervention (experimental treatment with 10 mg/day montelukast) or the control group (placebo group), during a 28-day treatment. Follow-up will finish 56 days after the start of treatment. The primary outcome will be health-related quality of life associated with respiratory symptoms according to the COPD Assessment Test 4 weeks after starting the treatment. The following are the secondary outcomes: (a) exercise capacity and oxygen saturation (1-min sit-to-stand test); (b) Post-COVID-19 Functional Status Scale; (c) other symptoms: asthenia, headache, mental confusion (brain fog), ageusia, and anosmia (Likert scale); (d) use of healthcare resources; (e) mortality; (f) sick leave duration in days; and (g) side effects of montelukast. ETHICS AND DISSEMINATION: This study has been approved by the Clinical Research Ethics Committee of the IDIAPJGol (reference number 21/091-C). The trial results will be published in open access, peer-reviewed journals and explained in webinars to increase awareness and understanding about long COVID among primary health professionals. TRIAL REGISTRATION: ClinicalTrials.gov NCT04695704 . Registered on January 5, 2021. EudraCT number 2021-000605-24. Prospectively registered.


Assuntos
COVID-19 , Acetatos , COVID-19/complicações , Ciclopropanos , Método Duplo-Cego , Humanos , Qualidade de Vida , Quinolinas , Ensaios Clínicos Controlados Aleatórios como Assunto , SARS-CoV-2 , Sulfetos , Resultado do Tratamento
2.
Huan Jing Ke Xue ; 43(1): 442-453, 2022 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-34989529

RESUMO

In order to ascertain the impact of pyrite mining on the surrounding farmland soil environment and human health, 42 surface soil samples (from 0-20 cm) were collected around the pyrite mining area in Longyou county. In this study, the concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and the pH in the topsoil were analyzed, and the concentration characteristics of heavy metals, source analysis, and human health risks assessment were studied using statistical analysis (SA), geo-accumulation index (Igeo), positive matrix factorization (PMF), and the health risk model. The average of ω(Cd), ω(Cu), ω(Pb), and ω(Zn) concentrations exceeded the background values of soils in Zhejiang province and China. According to the agricultural land pollution risk screening values (GB 15618-2018), Cd, Cu, Pb, and Zn were up to 82%, 49%, 42%, and 31%, respectively. The Igeo shows that the major pollutant element in the soils was Cd, followed by Cu, Pb, and Zn. The PMF analysis indicates that nature sources (As, Cr, and Ni), comprehensive pollution sources caused by high geological background and mining of ore-forming geological bodies (Cd, Cu, Pb, and Zn), and anthropogenic sources (Hg) were the three major sources of heavy metals in the study area, with contributions of 32%, 46%, and 22%, respectively. The results of the health risk assessment indicate that the major non-carcinogenic factor triggering risks was the ingestion of Pb; Cr exposure had carcinogenic risk for adults, and Cr and As exposure had carcinogenic risk for children.


Assuntos
Metais Pesados , Poluentes do Solo , Adulto , Criança , China , Monitoramento Ambiental , Fazendas , Humanos , Ferro , Metais Pesados/análise , Medição de Risco , Solo , Poluentes do Solo/análise , Sulfetos
3.
J Toxicol Sci ; 47(1): 31-37, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34987139

RESUMO

Brain susceptibility to methylmercury (MeHg) is developmentally and regionally specific in both humans and rodents, but the mechanism is not well clarified. Reactive sulfur species (RSS) with high nucleophilicity can react with MeHg, leading to the formation of a less toxic metabolite bismethylmercury sulfide, thus exerting cytoprotection. In this study, we assessed the variation of RSS content in the rat brain and evaluated its relevance in sensitivity to MeHg. Analyses of fetal/juvenile rat brains showed low RSS levels in early developmental stages. Site-specific analysis of adult rat brains revealed that cerebellar RSS levels were lower than those of the hippocampus. Microscopically, RSS levels of the granular cell layer were lower than those of the molecular layer in the cerebellum. Thus, low RSS levels corresponded with age and site of the brain that is vulnerable to MeHg. Taken together with the finding that brain RSS were consumed during MeHg exposure, these results indicate that RSS is a factor that defines the specificity of MeHg vulnerability in the brain.


Assuntos
Compostos de Metilmercúrio , Animais , Encéfalo , Cerebelo , Compostos de Metilmercúrio/toxicidade , Ratos , Sulfetos , Enxofre
4.
J Environ Manage ; 304: 114290, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34915384

RESUMO

The feasibility of pyrite as catalysts in the persulfate oxidation and electron donor for subsequent bacterial denitrification was investigated. The results demonstrated that pyrite-activated persulfate oxidation could efficiently degrade the organic matter in the effluent of biological landfill leachate treatment system, and COD removal efficiency of about 45% was achieved at the optimum parameters: pH = 6, pyrite dosage = 9.28 mM, dimensionless oxidant dose = 0.25. Among the dissolved organic matter, hydrophobic dissolved organic carbon (HO DOC), humic acids and building blocks were the main components. After the pyrite-activated persulfate oxidation, humic acids and HO DOC were primarily degraded, followed by building blocks, while low molecular weight neutrals were probably the degradation products. In the subsequent biological process, nitrate reduction was satisfactorily accomplished with autotrophic denitrification as the main pathway. When the influent nitrate concentration was about 180 mg L-1, the effluent nitrate concentration was stable below 20 mg L-1 with the nitrogen removal rate of about 108 mg L-1 d-1. To sum up, the pyrite-activated persulfate oxidation and the following biological denitrification was a feasible application in the effluent of biological landfill leachate treatment system.


Assuntos
Poluentes Químicos da Água , Reatores Biológicos , Desnitrificação , Ferro , Nitrogênio , Oxirredução , Sulfetos , Poluentes Químicos da Água/análise
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 268: 120708, 2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-34915231

RESUMO

Hydrogen polysulfides (H2Sn, n > 1) belongs to sulfane sulfur in the reactive sulfur species (RSS) family and plays a significant regulatory role in organisms. Highly selective and lysosome-located probes for detecting hydrogen polysulfides are rare. Thus, it is important to develop a technique to detect the changes of H2Sn level in lysosomes. In this work, a lysosome-targeting fluorescent probe for H2Sn was designed and developed based on a naphthalimide derivative. 4-Hydroxynaphthalimide was selected as the fluorescent group and 2-chloro-5-nitrobenzoate group was used as a specific recognition unit for H2Sn. A morpholine unit was chosen as a lysosome-located group. In the absence of H2Sn, the fluorescent probe exhibited almost no fluorescence. In the presence of H2Sn, the fluorescent probe showed strong fluorescence owing to H2Sn-mediated aromatic substitution-cyclization reactions. The fluorescence emission intensity at 548 nm of the probe showed a good linear relationship toward H2Sn in the range of 2.0 × 10-7 - 9.0 × 10-5 mol·L-1, and the detection limit was found to be 1.5 × 10-7 mol·L-1. The probe possessed a wide work range of pH, including the pH of physiological environment, and high selectivity for H2Sn. There are almost no cytotoxicity and the ability of detecting endogenous and exogenous H2Sn in lysosomes. These results indicate that the fluorescent probe can provide a good tool for intracellular and extracellular detection of H2Sn.


Assuntos
Corantes Fluorescentes , Naftalimidas , Hidrogênio , Lisossomos , Sulfetos , Enxofre
6.
Environ Pollut ; 295: 118697, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34929207

RESUMO

Acid mine drainage (AMD) due to the mining of sulfide deposits is one of the most important causes of water pollution worldwide. Remediation measures, especially in historical abandoned mines, require a deep knowledge of the geochemical characteristics of AMD effluents and metal fluxes, considering their high spatial and temporal evolution, and the existence of point and diffuse sources with a different response to rainfall events. This study investigates the temporal variations and hydrogeochemical processes affecting the composition of main AMD sources from the Tharsis mines (SW Spain), one of most important historical metal mining districts in the world. To address this, a fortnightly-monthly sampling was performed during two years in the main AMD sources and streams within the mine site covering different hydrological conditions. A seasonal pattern was observed linked to hydrological variations; higher pollutant concentrations were observed during the dry season (maximum values of 4,6 g/L of Al, 11,8 g/L of Fe, and 67 g/L of sulfate) and lower ones were observed during the rainy periods. Stream samples exhibited a negative correlation between electrical conductivity (EC) and flow, while positive values were observed in AMD sources, where groundwater fluxes were predominant. High flow also seems to be the main driver of Pb fluxes from AMD sources, as the concentration of Pb in waters increased notably during these events. The precipitation of secondary Fe minerals may limit the mobility of As and V, being retained in the proximity of mine sites. The concentration of Zn in waters seems to be controlled by the original grade in the metal deposit from which the waste is generated, together with the age of these wastes. The pollutant load delivered by the Tharsis mines to the surrounding water courses is very high; e.g., mean of 733 ton/yr of Al or 2757 ton/yr of Fe, deteriorating the streams and reservoirs downstream.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água , Ferro , Espanha , Sulfetos/análise , Poluentes Químicos da Água/análise
7.
Chemosphere ; 286(Pt 1): 131638, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34303908

RESUMO

Soil samples were collected from a representative arsenic (As) contaminated region under phytoremediation of hyperaccumulation plants. Relative abundance and diversity of microbial communities in the soil samples were characterized via 16S rRNA genes sequencing. At the phylum level, Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes and Firmicutes shows the highest abundance, accounting for more than 90 % of the classified sequences in the soil samples. Physicochemical parameters including pH, total organic carbon (TOC), cation exchange capacity (CEC), and electrical conductivity (EC), and heavy metal concentrations including total and bioaccessible contents in the soil samples were determined to investigate potential relationships between the microbial communities and the environmental factors. Principal component analysis (PCA) based on the operational taxonomic units (OTUs) matrix revealed distinct separation among the samples. The soil pH was confirmed as the dominant force to discriminate the soil samples with similar land use type and heavy metal contamination. There was little relevance between the total concentrations of heavy metals and the microbial communities. However, the bioaccessible concentrations of heavy metals were associated with the physicochemical parameters and relative abundances of bacterial genera according to correlation analyses. Although the soil samples were considerably contaminated by As, the abundances of bacterial phyla linked with As were lower than 1.0 % in most of the soil samples. The results indicated that the abundances of microbial communities in the soils were the consequence of concerted effects from all the environmental factors.


Assuntos
Metais Pesados , Microbiota , Poluentes do Solo , Arsenicais , Metais Pesados/análise , RNA Ribossômico 16S/genética , Solo , Microbiologia do Solo , Poluentes do Solo/análise , Sulfetos
8.
J Colloid Interface Sci ; 605: 129-137, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34311307

RESUMO

Lithium-sulfur (Li-S) batteries are greatly expected to be the favored alternatives in the next-generation energy-storage technologies due to their exceptional advantages. However, the shuttle effect and sluggish reaction kinetics of polysulfides largely hamper the practical success of Li-S batteries. Herein, a unique iron carbide (Fe3C) nanoparticles-embedded porous biomass-derived carbon (Fe3C-PBC) is reported as the excellent immobilizer and promoter for polysulfides regulation. Such a distinctive composite strongly couples the vast active sites of Fe3C nanoparticles and the conductive network of porous biomass-derived carbon. Therefore, Fe3C-PBC is endowed with outstanding adsorptivity and catalytic effect toward inhibiting the shuttle effect and facilitating the redox kinetics of polysulfides, demonstrated by the detailed experimental demonstrations and theoretical calculation. With these synergistic effects, the Fe3C-PBC/S electrode embraces a superb capacity retention of 82.7% at 2C over 500 cycles and an excellent areal capacity of 4.81 mAh cm-2 under the high-sulfur loading of 5.2 mg cm-2. This work will inspire the design of advanced hosts based on biomass materials for polysulfides regulation in pursuing the superior Li-S batteries.


Assuntos
Lítio , Nanopartículas , Biomassa , Carbono , Compostos Inorgânicos de Carbono , Compostos de Ferro , Porosidade , Sulfetos , Enxofre
9.
J Colloid Interface Sci ; 605: 296-310, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34329981

RESUMO

This paper presents the design of a new type of intelligent and versatile all-in-one therapeutic nanoplatform for the co-delivery of chemotherapeutic drugs and photosensitizers to facilitate multimodal antitumor treatment; the system is based on hyaluronic acid (HA)-modified manganese dioxide (MnO2)-enveloped hollow porous copper sulfide (CuS) nanoparticles (CuS@MnO2/HA NPs). In this system, a CuS inner shell allows for the co-loading of doxorubicin (DOX) and indocyanine green (ICG) and induces photothermal effects, and a biodegradable MnO2 external shell affords on-demand tumor microenvironment (TME)-triggered release and catalase- andFenton-like activities. Moreover, the HA modification endows the system with a CD44 receptor-mediated tumor-targeting property. The formulated DOX and ICG co-loaded CuS@MnO2/HA (DOX/ICG-CuS@MnO2/HA) NPs were found to exhibit excellent photothermal performance both in vitro and in vivo. In addition, DOX/ICG-CuS@MnO2/HA NPs were found to display both TME and near-infrared (NIR)-responsive controlled release properties. The NPs also have a superior reactive oxygen species (ROS) generation capacity due to the combination of enhanced ICG-induced singlet oxygen and CuS@MnO2-mediated hydroxyl radicals. The cellular uptake, fluorescence imaging property, cytotoxicity, and thermal imaging of these NPs were also evaluated. In tumor-bearing mice, the DOX/ICG-CuS@MnO2/HA NPs displayeda superior antitumor efficacy (2.57-fold) as compared with free DOX. Therefore, the developed DOX/ICG-CuS@MnO2/HA NPs have a great potential for use as an all-in-one nanotherapeutic agent for the efficient and precise induction of chemo/photothermal/photodynamic/chemodynamic therapy with superior antitumor efficacy and fewer side effects.


Assuntos
Nanopartículas , Preparações Farmacêuticas , Animais , Cobre , Doxorrubicina/farmacologia , Ácido Hialurônico , Compostos de Manganês , Camundongos , Óxidos , Fármacos Fotossensibilizantes , Fototerapia , Sulfetos
10.
Chemosphere ; 286(Pt 1): 131672, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34346328

RESUMO

The glass system SiO2-B2O3-Na2O3-ZnO containing 2 wt% CdS and 1 wt% ZnS was synthesized by the conventional melt quench method. Glass transition temperature and crystallization temperature was determined from Differential thermal analysis (DTA) measurement to optimize heat-treatment. The amorphous structure of the glass was confirmed by the X-ray diffraction (XRD) measurement. Glasses were heat-treated by optimized heat-treatment schedule to grow CdS/ZnS QDs and crystalline phases of CdS and ZnS were confirmed by the XRD measurement. High-Resolution Transmission Electron Microscopy (HRTEM) was used to determine the size and shape of quantum dots (QDs) grown in the glass matrix. The optical band gap was calculated from the absorption spectra and found to decrease with increase in size of QDs. Electron-hole recombination rate was studied using a decay time and impedance analyzer. Prepared samples were tested as a photocatalyst under sunlight for the degradation of indigo carmine (IC) dye and photodegradation efficiency was found to be 73.6 % and 87.2 % for samples CZ1 and CZ4 respectively. No significant change is observed in degradation efficiency even for 4 cycles which confirms the stability of prepared glasses for dye degradation.


Assuntos
Pontos Quânticos , Carmim , Índigo Carmim , Dióxido de Silício , Sulfetos , Compostos de Zinco
11.
J Hazard Mater ; 421: 126745, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364206

RESUMO

Sulfide precipitation is an efficient method to remove Cu(II) and As(III) from strongly acidic wastewater, but the instantaneous release of H2S from traditional sulfuration reagents causes serious H2S pollution. Moreover, the obtained precipitates are mixtures of CuS and As2S3, leading to difficulties in resource recovery. In this study, a calcium sulfide-organosilicon complex (CaS-OSCS), in which CaS was coated into a matrix of {[O1.5Si(CH2)3NH]CS}n (OSCS) via the coordination bonding, was developed. OSCS, as a matrix of CaS-OSCS, can ensure the sustained and stable release of H2S under strongly acidic conditions owing to its low swelling (1.75% swelling ratio) and excellent acid resistance. The release longevity of H2S from CaS-OSCS extended from 5 min up to 50 min compared with that from CaS because the hydrophobic OSCS prevented solution diffusing to the pores of CaS-OSCS and thus slowed down the hydrolysis of CaS in pores. 99% of Cu(II)/As(III) was precipitated without H2S escape, and the dosage of sulfuration reagents was reduced by 30%. In addition, CaS-OSCS improved the selective separation of copper from wastewater, and a separation factor between Cu(II) and As(III) reached 2376. This study provides a potential approach for the elimination of H2S pollution and selective recovery of copper.


Assuntos
Sulfeto de Hidrogênio , Águas Residuárias , Compostos de Cálcio , Preparações de Ação Retardada , Sulfetos
12.
Food Chem ; 367: 130754, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34384983

RESUMO

N-acetylneuraminic acid (Neu5Ac) is widely spread in many biologically significant glycans of mammals, commonly as a terminal α-glycoside. It is of great significance to develop analytical techniques for detection of Neu5Ac. Herein, a high-sensitive fluorescent biosensor for Neu5Ac has been developed based on FRET between CdSe/ZnS quantum dots (QDs) and BHQ2, as well as exonuclease III (Exo III)-assisted recycling amplification strategy. Employing the specially designed three-level FRET systems and fluorescent signal recovery mechanism, together with five-step recycling signal amplification chain reactions, an ultralow detection limit of 24 fM was achieved. Meanwhile, good linear response ranges within 0.2-12.5 pM and 12.5-1000 pM were founded. The assay has excellent performance in real sample detection, and thus offers great potential for detection of sialic acids modified glycans/lipids in the fields of medical diagnosis and food testing.


Assuntos
Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Animais , DNA , Exodesoxirribonucleases , Transferência Ressonante de Energia de Fluorescência , Limite de Detecção , Ácidos Siálicos , Sulfetos , Compostos de Zinco
13.
J Colloid Interface Sci ; 606(Pt 1): 261-271, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34390993

RESUMO

Morphological and structural characteristics of semiconductors have a significant impact on their gas sensing characteristics. Reasonable design and synthesis of heterojunctions with special structures can effectively improve sensor performance. Herein, a cobalt oxide (Co3O4) nanofibers/cadmium sulfide (CdS) nanospheres hybrid was synthesized by an electrospinning method combined with a hydrothermal method to detect acetone gas. By adjusting loading amount of CdS, the sensing performance of CdS/Co3O4 sensor for acetone at room temperature (25 °C) was greatly ameliorated. In particular, the response of CdS/Co3O4 to 50 ppm acetone gas increased by 25% under 520 nm green light, meanwhile, the response/recovery time was shortened to 5 s/4 s. This is attributed to the heterojunction formed between CdS and Co3O4 as well as the influence of light excitation on the carrier concentration of the surfaces. Meanwhile, the unique high-porosity fiber structure and the catalytic action of cobalt ions also play an essential role in improving the performance. Furthermore, practical diabetic breath was experimentally simulated and proved the potential of the sensor in the future application of disease-assisted diagnosis.


Assuntos
Diabetes Mellitus , Nanofibras , Nanosferas , Acetona , Biomarcadores , Compostos de Cádmio , Humanos , Sulfetos
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120253, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34391992

RESUMO

Globally, the environmental pollution is one of the major issues causing toxicity towards human and aquatic life. We have developed a facile and innovative sensing approach for detection of sulphide ions (S2-) present in the aqueous media using Ag0 decorated Cr2S3 NPs embedded on PVP matrix (Ag/Cr2S3-PVP). Based on the SPR phenomena, the detection of S2- ions was established. The nanohybrid was characterized using various techniques such as UV-vis spectrophotometer, High-Resolution Transmission Electron Microscopy (HR-TEM), Thermal Gravimetric Analysis (TGA), X-ray diffraction analysis(XRD), Energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The yellowish colour of Ag/Cr2S3-PVP nanohybrid turned to brown colour in presence of S2- ions. The selectivity and sensitivity of the prepared probe was studied against the other interfering metal ions. In addition, the effect of different concentration of S2- ions in the nanohybrid solution was investigated and the Limit of detection (LOD) was found to be 6.6 nM. The good linearity was found over the range of 10 nM to 100 µM with R2 value of 0.981. The paper strip based probe was developed for rapid onsite monitoring of S2- ions. The proposed method is found to be cost-effective, rapid, and simple. We have validated the practical applicability of the prepared probe for determining the concentration of S2- ions in real water samples.


Assuntos
Colorimetria , Nanopartículas Metálicas , Humanos , Limite de Detecção , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfetos , Água
15.
Food Chem ; 367: 130741, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34399272

RESUMO

Volatile sulfur-containing compounds (VSCs) provide an important contribution to foods due to their special odors. In this study, VSCs in 21 cold-pressed rapeseed oils (CROs) from 9 regions in China were extracted and separated by headspace solid-phase microextraction combined with gas chromatography coupled with sulfur chemiluminescence detection. 19 VSCs were identified by authentic standards, and the total concentration of VSCs in all CROs ranged from 49.0 to 18129 µg/kg. Dimethyl sulfide (DMS), with its high odor activity value (7-14574), was the most significant aroma contributor to the CROs. Furthermore, S-methylmethionine (SMM) in rapeseed was first affirmed by ultra-performance liquid chromatography-tandem mass spectrometry and isotope quantitation. The positive correlation coefficient between DMS and SMM was 0.793 (p < 0.05), which confirmed SMM as a crucial precursor of DMS in CROs. This study provided a theoretical basis for selecting rapeseed materials by the distribution of essential VSCs and the source of DMS.


Assuntos
Compostos de Enxofre , Compostos Orgânicos Voláteis , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Óleo de Brassica napus , Sulfetos , Enxofre , Compostos de Enxofre/análise , Espectrometria de Massas em Tandem , Compostos Orgânicos Voláteis/análise
16.
J Colloid Interface Sci ; 606(Pt 1): 688-695, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34416458

RESUMO

Herein, we systematically investigated the mechanisms of OH production and arsenic (As(III)) oxidation induced by sulfur vacancy greigite (Fe3S4) under anoxic and oxic conditions. Reactive oxygen species analyses revealed that sulfur vacancy-rich Fe3S4 (SV-rich Fe3S4) activated molecular oxygen to produce hydrogen peroxide (H2O2) via a two-electron reduction pathway under oxic conditions. Subsequently, H2O2 was decomposed to OH via the Fenton reaction. Additionally, H2O was directly oxidized to OH by surface high-valent iron (Fe(IV)) resulting from the abundance of sulfur vacancies in Fe3S4 under anoxic/oxic conditions. These differential OH-generating mechanisms of Fe3S4 resulted in higher OH production of SV-rich Fe3S4 compared to sulfur vacancy-poor Fe3S4 (SV-poor Fe3S4). Moreover, the OH production rate of SV-rich Fe3S4 under oxic conditions (19.3 ± 1.0 µM•h-1) was 1.6 times greater than under anoxic conditions (11.8 ± 0.4 µM•h-1). As(III) removal experiments and X-ray photoelectron spectra (XPS) showed that both OH production pathways were favorable for As(III) oxidation, and a higher concentration of As(V) was immobilized on the surface of SV-rich Fe3S4 under oxic conditions. This study provides new insights concerning OH production and environmental pollutants removal mechanisms on surface defects of Fe3S4 under anoxic and oxic conditions.


Assuntos
Arsênio , Peróxido de Hidrogênio , Radical Hidroxila , Ferro , Oxirredução , Sulfetos , Enxofre
17.
Chemosphere ; 286(Pt 3): 131876, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34418657

RESUMO

Herein, sulfide-modified nanoscale zero-valent iron (S-nZVI) was prepared by a liquid-phase reduction route and then applied to activate persulfate (PS) for the degradation of chloramphenicol (CAP). The effects of Fe/S molar ratio, catalyst dosage, PS concentration, initial pH, and co-existing ions (Cl-, SO42-, CO32-) on the catalytic performance of S-nZVI/PS system were investigated. Simultaneously, the fluctuations of solution pH, oxidation-reduction potential, dissolved oxygen, and Fe2+ concentration were also monitored during the reaction. Results shown that 98.8 % of CAP could be removed under the optimum reaction conditions (S-nZVI dosage = 0.1 g/L, PS concentration = 3 mM, initial pH = 6.86). Compared to the pristine nZVI, the sulfidation behavior could critically improve the removal efficiency of CAP, ascribe to the enhancements of hydrophobicity of nZVI, production of hydroxyl radicals, and salt resistance. Furthermore, possible degradation pathways of CAP in S-nZVI/PS system were inferred based on liquid chromatography-mass spectrometry (LC-MS) and density functional theory (DFT) calculations. This study proves that the S-nZVI is a more promising catalyst for activating PS than nZVI, especially in the field of saline pharmaceutical wastewater treatment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cloranfenicol , Ferro , Sulfetos , Poluentes Químicos da Água/análise
18.
Biosens Bioelectron ; 199: 113892, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34933225

RESUMO

Incorporating quantum dots (QDs) into dendritic mesoporous silica nanoparticles (DMSNs) for signal amplification of label materials represents an efficient strategy to improve the performance of lateral flow immunoassays (LFIAs). In this work, it is found that the CdSe/ZnS QD's size matters for balancing their loading amount and quantum yields (QYs) in the DMSNs-QDs based label materials and ultimately determining the performance of LFIA. The impacts of three CdSe/ZnS QDs with diameters of 9.1, 10.5 and 11.7 nm on CdSe/ZnS QDs incorporation and LFIA applications are studied. The increase of CdSe/ZnS QDs size from 9.1 to 11.7 nm results in a decrease in CdSe/ZnS QDs loading amount and an increase in QYs of incorporated CdSe/ZnS QDs. This trade-off leads to an optimized CdSe/ZnS QDs size of 10.5 nm, which exhibits the best LFIA performance due to the balanced QDs loading (2.26 g g-1) and QY (57.1%). The 10.5 nm CdSe/ZnS QDs incorporated DMSNs-QDs for C-reactive protein (CRP) detection achieved a limit of detection of 5 pg mL-1 (equivalent to 4.2 × 10-14 M) with naked eye, which is lower than literature reports and commercial LFIA products. This study demonstrates that the CdSe/ZnS QD's size matters for improving the quality of DMSNs-QDs and their LFIA performance for CRP determination, providing new insights into the rational design of advanced label materials for improving LFIA performance.


Assuntos
Técnicas Biossensoriais , Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Proteína C-Reativa , Imunoensaio , Sulfetos , Compostos de Zinco
19.
Methods Mol Biol ; 2371: 247-259, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34596852

RESUMO

The Random nonstandard Peptides Integrated Discovery (RaPID) system enables efficient screening of macrocyclic peptides with high affinities against target molecules. Random peptide libraries are prepared by in vitro translation using the Flexible In vitro Translation (FIT) system, which allows for incorporation of diverse nonproteinogenic amino acids into peptides by genetic code reprogramming. By introducing an N-chloroacetyl amino acid at the N-terminus and a Cys at the downstream, macrocyclic peptide libraries can be readily generated via posttranslational thioether formation. Here, we describe how to prepare a thioether-closed macrocyclic peptide library, and its application to the RaPID screening.


Assuntos
Peptídeos/análise , Aminoácidos , Código Genético , Ligantes , Biblioteca de Peptídeos , Peptídeos/genética , Sulfetos
20.
Environ Res ; 203: 111797, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34339704

RESUMO

The production of shrimp is often performed in earthen outdoor ponds in which the high input of feed and faeces on the bottom can result in deterioration of the water quality, which negatively impacts the animals and the environment. Here, we investigate the potential of sodium molybdate (Na2MoO4·2H2O), sodium nitrate (NaNO3) and sodium percarbonate (Na2CO3·1.5H2O2) to control sulphide production in a simulated shrimp pond bottom system that included the sediment, overlaying artificial seawater and organic matter input in the form of shrimp feed and shrimp faeces. Sediment depth gradient measurements of oxygen, H2S and pH were obtained during 7 days of incubation using microelectrodes. The most significant impact in terms of H2S, was observed for 50 mg/L sodium molybdate. At the water-sediment interface, there was up to 73% less H2S detected for this treatment in comparison to a control treatment, while in the deeper layers of the sediment it was up to 47% less H2S. The residual sulphate concentrations in the molybdate treated samples were 16 ± 4% higher than the control, indicating an inhibition in sulphate reduction. Nitrate and sodium percarbonate treatments also showed a limited capacity to decrease H2S entering in the water column, yet no clear difference in H2S concentrations in the sediment compared to the control were observed. Molybdate treatment appears to work through the inhibition of sulphate reducing bacteria in situ for the control of H2S production better than the chemical oxygen boosters or nitrate treatment.


Assuntos
Sedimentos Geológicos , Lagoas , Animais , Molibdênio , Água do Mar , Sulfetos
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