RESUMO
BACKGROUND: This study employs systematic review and meta-analysis to explore the incidence and characteristics of spinal cord injury (SCI) between 2000 and 2021, aiming to provide the most recent and comprehensive data support for the prevention, diagnosis, treatment, and care of SCI. METHODS: Systematic searches were conducted on epidemiological studies of SCI published between January 1, 2000, and March 29, 2024. Meta-analysis, subgroup analysis, meta-regression, publication bias detection, and literature quality assessment were extensively utilized. RESULTS: The pooled results from 229 studies indicated that the overall incidence rate of SCI was 23.77 (95% CI, 21.50-26.15) per million people, with traumatic spinal cord injuries (TSCI) at a rate of 26.48 (95% CI, 24.15-28.93) per million people, and non-traumatic spinal cord injuries (NTSCI) at a rate of 17.93 (95% CI, 13.30-23.26) per million people. The incidence of TSCI exhibited a marked age-related increase and was significantly higher in community settings compared to hospital and database sources. Males experienced TSCI at a rate 3.2 times higher than females. Between 2000 and 2021, the incidence of TSCI remained consistently high, between 20 and 45 per million people, whereas NTSCI incidence has seen a steady rise since 2007, stabilizing at a high rate of 25-35 per million people. Additionally, the incidence of TSCI in developing countries was notably higher than that in developed countries. There were significant differences in the causes of injury, severity, injury segments, gender, and age distribution among the TSCI and NTSCI populations, but the proportion of male patients was much higher than that of female patients. Moreover, study quality, country type, and SCI type contributed to the heterogeneity in the meta-analysis. CONCLUSIONS: The incidence rates of different types of SCI remain high, and the demographic distribution of SCI patients is changing, indicating a serious disease burden on healthcare systems and affected populations. These findings underscore the necessity of adopting targeted preventive, therapeutic, and rehabilitative measures based on the incidence and characteristics of SCI.
Assuntos
Traumatismos da Medula Espinal , Traumatismos da Medula Espinal/epidemiologia , Humanos , Incidência , Saúde Global , Feminino , MasculinoRESUMO
The catalytic transformation of N2 to NH3 by transition metal complexes is of great interest and importance but has remained a challenge to date. Despite the essential role of vanadium in biological N2 fixation, well-defined vanadium complexes that can catalyze the conversion of N2 to NH3 are scarce. In particular, a V(NxHy) intermediate derived from proton/electron transfer reactions of coordinated N2 remains unknown. Here, we report a dinitrogen-bridged divanadium complex bearing POCOP (2,6-(tBu2PO)2-C6H3) pincer and aryloxy ligands, which can serve as a catalyst for the reduction of N2 to NH3 and N2H4. Low-temperature protonation and reduction of the dinitrogen complex afforded the first structurally characterized neutral metal hydrazido(2-) species ([V]âNNH2), which mediated 15N2 conversion to 15NH3, indicating that it is a plausible intermediate of the catalysis. DFT calculations showed that the vanadium hydrazido complex [V]âNNH2 possessed a N-H bond dissociation free energy (BDFEN-H) of as high as 59.1 kcal/mol. The protonation of a vanadium amide complex ([V]-NH2) with [Ph2NH2][OTf] resulted in the release of NH3 and the formation of a vanadium triflate complex, which upon reduction under N2 afforded the vanadium dinitrogen complex. These transformations model the final steps of a vanadium-catalyzed N2 reduction cycle. Both experimental and theoretical studies suggest that the catalytic reaction may proceed via a distal pathway to liberate NH3. These findings provide unprecedented insights into the mechanism of N2 reduction related to FeV nitrogenase.
Assuntos
Amônia , Vanádio , Amônia/química , Oxirredução , Nitrogenase/metabolismo , Prótons , CatáliseRESUMO
Lignin separation from natural lignocellulose for the preparation of lignin nanoparticles (LNPs) is often challenging owing to the recalcitrant and complex structure of lignocellulose. This paper reports a strategy for the rapid synthesis of LNPs via microwave-assisted lignocellulose fractionation using ternary deep eutectic solvents (DESs). A novel ternary DES with strong hydrogen bonding was prepared using choline chloride, oxalic acid, and lactic acid in a 1:0.5:1 ratio. Efficient fractionation of rice straw (0.5 × 2.0 cm) (RS) was realized by the ternary DES under microwave irradiation (680 W) within only 4 min, and 63.4% of lignin could be separated from the RS to prepare LNPs with a high lignin purity (86.8%), an average particle size of 48-95 nm, and a narrow size distribution. The mechanism of lignin conversion was also investigated, which revealed that dissolved lignin aggregated into LNPs via π-π stacking interactions.
Assuntos
Lignina , Oryza , Lignina/química , Solventes Eutéticos Profundos , Micro-Ondas , Solventes/química , Biomassa , HidróliseRESUMO
An efficient copper-iodine cocatalyzed intermolecular C-H aminocyanation of indoles with a broad substrate scope has been developed for the first time. This method enables highly step-economic access to 2-amino-3-cyanoindoles in moderate to good yields and provides a complementary strategy for the regioselective difunctionalization of carbonâcarbon double bonds of interest in organic synthesis and related areas. Mechanistic studies suggest that these transformations are initiated by iodine-mediated C2-H amination with azoles, followed by copper-catalyzed C3-H cyanation with ethyl cyanoformate.
Assuntos
Indóis , Iodo , Azóis/química , Catálise , Cobre/química , Indóis/química , Iodetos , Iodo/químicaRESUMO
INTRODUCTION AND AIM: The use of aspirin is a potential protective factor against the development of hepatocellular carcinoma (HCC). Therefore, we conducted a meta-analysis to evaluate the contribution of aspirin to the risk of HCC. METHODS: We searched for PubMed and EMBASE through September 2021. RESULTS: Eighteen studies (16 cohort, 2 case-control) were included. Aspirin users were less likely to develop HCC than nonusers [adjusted odds ratio (OR), 0.54; 95% confidence interval (CI): 0.44-0.66]. Stratified analysis showed that aspirin reduced the risk of HCC in Asian and Western populations (OR, 0.59 vs. 0.67). Besides, aspirin has protective effects against HCC after hepatitis B virus (OR, 0.70; 95% CI: 0.52-0.93) and hepatitis C virus infections (OR, 0.41; 95% CI: 0.23-0.73). Aspirin has protective effects on people with chronic liver disease (OR, 0.46; 95% CI: 0.31-0.67) and on the general population (OR, 0.65; 95% CI: 0.54-0.79). In addition, confounding factors have an important impact on the results of aspirin prevention of liver cancer before (OR, 0.28; 95% CI: 0.06-1.27) and after (OR, 0.58; 95% CI: 0.47-0.71) adjustment. Further studies have shown that those in the long duration group do not experience better effects in preventing HCC (OR, 0.62 vs. 0.63). A further meta-analysis of 3 articles showed that the use of aspirin did not increase the risk of bleeding in patients with HCC (OR, 1.19; 95% CI: 0.87-1.64). CONCLUSION: Our meta-analysis shows that the use of aspirin is associated with a lower risk of liver cancer.
Assuntos
Carcinoma Hepatocelular , Hepatite C , Neoplasias Hepáticas , Aspirina/uso terapêutico , Carcinoma Hepatocelular/epidemiologia , Carcinoma Hepatocelular/prevenção & controle , Vírus da Hepatite B , Humanos , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/prevenção & controle , Fatores de RiscoRESUMO
A novel core-shell structured Fe3O4@GO-CoPc magnetic catalyst, which is with magnetite (Fe3O4) as the core, graphene oxide (GO) as the interlayer and cobalt-phthalocyanine (CoPc) as the shell, was successfully prepared and used as a heterogeneous photo-Fenton catalyst for tetracycline (TC) degradation in this work. The core-shell structure of the catalyst was confirmed by XRD, FTIR, SEM and TEM. BET and magnetic hysteresis loops measurements indicated that Fe3O4@GO-CoPc catalyst owned large specific surface area and could be easily recovered under an external magnetic field. Meanwhile, the experimental results of TC degradation demonstrated that the photo-Fenton efficiency of Fe3O4@GO-CoPc was excellent. When the reaction time was 120 min, TC could be degraded almost completely in the photo-Fenton system with Fe3O4@GO-CoPc. The high photo-Fenton catalytic activity of Fe3O4@GO-CoPc could be resulted from the effective transfer of photo-generated electrons between CoPc and Fe3O4 by GO. Moreover, the main reaction species, â¢OH, O2â¢-, 1O2 and h+, were verified by the analysis of active species in this system. Finally, the mechanism analyses and quantitative analysis results of active species indicated that the introduction of GO accelerated the cycle between Fe(II) and Fe(III) as well as improved the effective utilization of H2O2 (the efficiency of conversion of H2O2 to â¢OH).
Assuntos
Grafite , Peróxido de Hidrogênio , Catálise , Compostos Férricos , Grafite/química , Peróxido de Hidrogênio/química , TetraciclinaRESUMO
Severe hand, foot, and mouth disease (HFMD) caused by enterovirus 71 (EV71) infection is associated with high mortality and disability. DC-SIGN, a receptor for EV71, is widely distributed in dendritic cells and may influence the severity of HFMD caused by EV71 infection. This observational study attempts to explore whether single-nucleotide polymorphisms (SNPs) in DC-SIGN are related to the severity of EV71-associated HFMD. Based on linkage disequilibrium and functional predictions, two DC-SIGN SNPs were selected and tested to explore their potential association with the severity of HFMD caused by EV71 infection. Two hundred sixteen Han Chinese children with HFMD caused by EV71 were enrolled to obtain clinical data, including the severity of HFMD, serum DC-SIGN levels, and DC-SIGN SNPs. We found a significant association between the rs7248637 polymorphism (A vs. G: OR = 0.644, 95% CI = 0.515-0.806) and the severity of HFMD caused by EV71 infection, as well as the rs4804800 polymorphism (A vs. G: OR = 1.539, 95% CI =1.229-1.928). These two DC-SIGN SNPs may have an effect on the severity of HFMD caused by EV71 infection.
Assuntos
Moléculas de Adesão Celular/genética , Infecções por Enterovirus/genética , Predisposição Genética para Doença/genética , Doença de Mão, Pé e Boca/genética , Lectinas Tipo C/genética , Receptores de Superfície Celular/genética , Povo Asiático/genética , Moléculas de Adesão Celular/sangue , Criança , Pré-Escolar , China/epidemiologia , Enterovirus Humano A , Infecções por Enterovirus/epidemiologia , Infecções por Enterovirus/patologia , Feminino , Estudos de Associação Genética , Genótipo , Doença de Mão, Pé e Boca/epidemiologia , Doença de Mão, Pé e Boca/patologia , Humanos , Lactente , Lectinas Tipo C/sangue , Masculino , Polimorfismo de Nucleotídeo Único , Receptores de Superfície Celular/sangue , Índice de Gravidade de DoençaRESUMO
Achievement of a 'clinical cure' in chronic hepatitis B (CHB) implies sustained virological suppression and immunological control over the infection, which is the ideal treatment goal according to domestic and international CHB management guidelines. Clinical practice has shown encouraging results for specific patient cohorts using tailored treatment regimens. These regimens incorporate either nucleos(t)ide analogs, immunomodulatory agents such as pegylated interferon α, or a strategic combination of both, sequentially or concurrently administered. Despite these advancements in the clinical handling of hepatitis B, achieving a clinical cure remains elusive for a considerable subset of patients due to the number of challenges that preclude the realization of optimal treatment outcomes. These include, but are not limited to, the emergence of antiviral resistance, incomplete immune recovery, and the persistence of covalently closed circular DNA. Moreover, the variance in response to interferon therapy and the lack of definitive biomarkers for treatment cessation also contribute to the complexity of achieving a clinical cure. This article briefly overviews the current research progress and existing issues in pursuing a clinical cure for hepatitis B.
RESUMO
A directing-group-free strategy for oxidative regioselective aminochalcogenation of indolines with amines and dichalconides is presented. This strategy combines tandem coupling sequences and oxidative dehydrogenation methods in a multi-component reaction, enabling the fast construction of a series of C2,3- or C2,5-aminochalcogenated indole derivatives. Moreover, the application of this synthetic approach is demonstrated through the late-stage modification of pharmaceuticals and the derivatization of the products, highlighting its potential and significance.
RESUMO
The photo-activation and photo-dissolution processes of pyrite (FeS2) can affect the environmental behavior of the co-existing hexavalent chromium (Cr(VI)). But the photochemical performance of FeS2 is intimately dependent on its exposed facets. Herein, FeS2 nanosheets (FeS2 NS) and FeS2 nanocubes (FeS2 NC) with the dominant exposed facets of (001) and (210)/(100) respectively are prepared. The more Fe3+, Fe2+, and SO42- are released in the FeS2 NS system than the other system due to its more excellent generation ability of photogenerated electrons and reactive oxygen species. The higher surface energy on (001) facet leads to the faster dissolution rate of FeS2 NS. Due to the optimal production ability of photogenerated electrons and Fe2+ of (001) facet, the much higher Cr(VI) elimination efficiency in the FeS2 NS system is observed than that in the FeS2 NC (72.8%) system within 120 min. This work could help to unveil the influence of FeS2 on the fate of Cr(VI) in surface environment, and offer a theoretical support to clarify the influence of heavy metal ions on the iron sulfide minerals.
RESUMO
Research has shown that plants have the ability to detect environmental changes and generate electrical signals in response. These electrical signals can regulate the physiological state of plants and produce corresponding feedback. This suggests that plants have the potential to be used as biosensors for monitoring environmental information. However, there are current challenges in linking environmental information with plant electrical signals, especially in collecting and classifying the corresponding electrical signals under soil moisture gradients. This study documented the electrical signals of clivia under different soil moisture gradients and created a dataset for classifying electrical signals. Subsequently, we proposed a lightweight convolutional neural network (CNN) model (PlantNet) for classifying the electrical signal dataset. Compared to traditional CNN models, our model achieved optimal classification performance with the lowest computational resource consumption. The model achieved an accuracy of 99.26%, precision of 99.31%, recall of 92.26%, F1-score of 99.21%, with 0.17M parameters, a size of 7.17MB, and 14.66M FLOPs. Therefore, this research provides scientific evidence for the future development of plants as biosensors for detecting soil moisture, and offers insight into developing plants as biosensors for detecting signals such as ozone, PM2.5, Volatile Organic Compounds(VOCs), and more. These studies are expected to drive the development of environmental monitoring technology and provide new pathways for better understanding the interaction between plants and the environment.
Assuntos
Técnicas Biossensoriais , Aprendizado Profundo , Monitoramento Ambiental , Solo , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Solo/química , Monitoramento Ambiental/métodos , Monitoramento Ambiental/instrumentação , Redes Neurais de Computação , Água/química , Água/análise , Plantas/químicaRESUMO
Phthalates acid esters (PAEs) have accumulated in soil and crops like wheat as a result of the widespread usage of plastic films. It is yet unclear, nevertheless, how these dynamic variations in PAE accumulation in wheat tissues relate to rhizosphere bacteria in the field. In this work, a field root-bag experiment was conducted to examine the changes of PAEs accumulation in the rhizosphere soil and wheat tissues under film residue conditions at four different growth stages of wheat, and to clarify the roles played by the microbial community in the alterations. Results showed that the plastic film residues significantly increased the concentrations of PAEs in soils, wheat roots, straw and grains. The maximum ΣPAEs concentration in soils and different wheat tissues appeared at the maturity, with the ΣPAEs concentration of 1.57 mg kg-1, 4.77 mg kg-1, 5.21 mg kg-1, 1.81 mg kg-1 for rhizosphere soils, wheat roots, straw and grains, respectively. The plastic film residues significantly changed the functions and components of the bacterial community, increased the stochastic processes of the bacterial community assembly, and reduced the complexity and stability of the bacterial network. In addition, the present study identified some bacteria associated with plastic film residues and PAEs degradation in key-stone taxa, and their relative abundances were positive related to the ΣPAEs concentration in soils. The PAEs content and key-stone taxa in rhizosphere soil play a crucial role in the formation of rhizosphere soil bacterial communities. This field study provides valuable information for better understanding the role of microorganisms in the complex system consisting of film residue, soil and crops.
Assuntos
Ácidos Ftálicos , Rizosfera , Microbiologia do Solo , Poluentes do Solo , Triticum , Triticum/microbiologia , Poluentes do Solo/análise , Poluentes do Solo/metabolismo , Ácidos Ftálicos/metabolismo , Plásticos/metabolismo , Ésteres/análise , Ésteres/metabolismo , Bactérias/metabolismo , Solo/química , Microbiota , Raízes de Plantas/microbiologia , Raízes de Plantas/metabolismoRESUMO
BACKGROUND: Cirrhosis is a disease that imposes a heavy burden worldwide, but its incidence varies widely by region. Therefore, we analysed data on the incidence and mortality of cirrhosis in 204 countries and territories from 1990-2019 and projected the disease development from 2019-2039. METHODS: Data on the incidence and mortality of liver cirrhosis from 1990 to 2019 were acquired from the public Global Burden of Disease (GBD) study. In addition, the average annual percentage change (AAPC) and estimated annual percentage change (EAPC) of the age-standardized rate (ASR) of cirrhosis in different regions were calculated. The estimates of risk factor exposure were summarized, and the proportion of causes and risk factors of liver cirrhosis and their relationship with the human development index (HDI) and socio-demographic index (SDI) were analysed. Trends in the incidence of cirrhosis in 2019-2039 were predicted using Nordpred and BAPC models. RESULTS: Globally, the ASR of cirrhosis incidence decreased by 0.05% per year from 25.7/100,000 in 1990 to 25.3/100,000 in 2019. The mortality risk associated with cirrhosis is notably lower in females than in males (13 per 100,000 vs 25 per 100,000). The leading cause of cirrhosis shifted from hepatitis B to C. Globally, alcohol use increased by 14%. In line, alcohol use contributed to 49.3% of disability-adjusted life years (DALYs) and 48.4% of global deaths from liver cirrhosis. Countries with a low ASR in 1990 experienced a faster increase in cirrhosis, whereas in 2019, the opposite was observed. In countries with high SDI, the ASR of cirrhosis is generally lower. Finally, projections indicate that the number and incidence of cirrhosis will persistently rise from 2019-2039. CONCLUSIONS: Cirrhosis poses an increasing health burden. Given the changing etiology, there is an imperative to strengthen the prevention of hepatitis C and alcohol consumption, to achieve early reduce the incidence of cirrhosis.
This study is an updated assessment of liver cirrhosis prevalence trends in 204 countries worldwide and the first to project trends over the next 20 years.The disease burden of cirrhosis is still increasing, and despite the decline in ASR, the number and prevalence of cirrhosis will continue to increase over the next two decades after 2019.It is alarming that the global surge in alcohol use is accompanied by an increase in DALYs and deaths due to liver cirrhosis.Liver cirrhosis remains a noteworthy public health event, and our study can further guide the development of national healthcare policies and the implementation of related interventions.
Assuntos
Previsões , Carga Global da Doença , Saúde Global , Cirrose Hepática , Humanos , Carga Global da Doença/tendências , Cirrose Hepática/epidemiologia , Masculino , Feminino , Incidência , Fatores de Risco , Saúde Global/estatística & dados numéricos , Saúde Global/tendências , Pessoa de Meia-Idade , Adulto , Idoso , Anos de Vida Ajustados por Qualidade de VidaRESUMO
Endoplasmic reticulum (ER) degradation via autophagy is a process that maintains ER homeostasis when cells are in a state of stress and is associated with many diseases; however, the role of hypoxia inducible factor-1α (HIF-1α)-mediated ER degradation and the related regulatory pathway in acute kidney injury (AKI) still needs to be further established. In the present study, an in vivo AKI model was induced in mice via the ischemiaâreperfusion (IR) method. The results revealed that HIF-1α and BNIP3 were increased, and autophagy and ER degradation were activated in the kidneys of AKI mice, whereas HIF-1α knockout significantly inhibited BNIP3, autophagy and ER degradation, accompanied by aggravated kidney injury. Overexpression of HIF-1α in vitro significantly increased BNIP3, autophagy and ER degradation, whereas inhibition of BNIP3 significantly reversed the effects of HIF-1α. In addition, the in vitro inhibition of autophagy with chloroquine significantly reversed the effects of HIF-1α on cell apoptosis. Moreover, selectively overexpressing BNIP3 on the ER membrane significantly increased ER degradation via autophagy and decreased cell apoptosis in vitro. These data indicate that HIF-1α/BNIP3-mediated ER degradation via autophagy in tubular cells protects against IR-induced AKI.
RESUMO
The oxidation of pyrite (FeS2) not only adversely affects the environment, but also plays a critical role in the geochemical evolution of Fe and S elements. However, the oxidation rate of FeS2 is often controlled by its exposed crystal facets. Herein, the oxidation behaviors and mechanisms of naturally existing FeS2(100) and FeS2(210) crystals are investigated. The adsorption models of O2 on FeS2(100) and FeS2(210) facets are established, additionally, their corresponding surface energies, O2 adsorption sites and energies are also obtained using Density Functional Theory (DFT) calculations. These results suggest that the FeS2(210) facet more readily reacts with O2 because it has more unsaturated coordination of Fe atoms compared with the FeS2(100) facet. Moreover, electrochemical results such as EIS, Tafel and CV curves further prove that FeS2(210) possesses a higher oxidation rate than that of FeS2(100). The results of chemical oxidation experiments and XPS analyses show that FeS2(210) can produce more total Fe, SO42- and H+ than FeS2(100). Furthermore, various intermediate S species such as SO32-, S2O32-, S3O62-, S4O62- and S5O62- are also detected. This work can provide a basis for understanding the oxidation mechanism of facet-dependent FeS2 and the geochemical evolution of Fe and S elements.
Assuntos
Ferro , Sulfetos , Ferro/química , Oxirredução , Sulfetos/química , Enxofre/químicaRESUMO
In previous works, both tannic acid (TA) and organosilane-based passivators have been proven to possess good inhibition effects on pyrite oxidation, which could effectively prevent acid mine drainage (AMD) generation at the source. However, the hydrophilicity of TA passivation film and the complex coating process of organosilane-based passivators (high temperature conditions were required during the process carried out) may limit their further practical use. Therefore, to achieve the purpose of better coating treatment of pyrite under mild conditions, TA and γ-mercaptopropyltrimethoxysilane (PropS-SH) were introduced to synergistically passivate pyrite in this work. Electrochemistry tests and chemical leaching experiments both confirmed that PropS-SH-TA coated pyrite had better oxidation resistance than raw pyrite and single PropS-SH or TA coated pyrite. Additionally, the analyses of scanning electron microscopy (SEM) measurements and static water contact angle tests demonstrated that a scaly coating was formed on PropS-SH-TA coated pyrite surface, which may be the reason for the significant improvement of its surface hydrophobicity. Finally, the study on the film-forming mechanism of PropS-SH-TA composite passivator displayed that the benzoquinone derivatives formed by TA could copolymerize with PropS-SH through Michael addition or Schiff base reaction, which constructed a dense hydrophobic film on pyrite surface. The newly formed composite film could provide a better oxidation barrier for pyrite based on TA passivation film.
Assuntos
Ferro , Compostos de Organossilício , Ferro/química , Sulfetos/química , OxirreduçãoRESUMO
The easy recombination of photoexcited electron-hole pairs is a serious constraint for the application of photocatalysts. In this work, a range of BiOClxI1-x solid solutions with abundant oxygen vacancies (BiOClxI1-x-OVs) were synthesized. In particular, the optimal BiOCl0.5I0.5-OVs sample exhibited almost 100% removal of bisphenol A (BPA) within 45 min visible light exposure, which was 22.4, 3.1 and 4.5 times greater than BiOCl, BiOCl-OVs and BiOCl0.5I0.5, respectively. Besides, the apparent quantum yield of BPA degradation reaches 0.24%, better than some other photocatalysts. Benefiting from the synergism of oxygen vacancies and solid solution, BiOCl0.5I0.5-OVs gained an enhanced photocatalytic capacity. Oxygen vacancies induced an intermediate defective energy level in BiOClxI1-x-OVs materials, promoting the generation of photogenerated electrons and the molecular oxygen adsorption to produce more active oxygen radicals. Meanwhile, the fabricated solid solution structure enhanced the internal electric field between BiOCl layers, achieving rapid migration of photoexcited electrons and effective segregation of photoinduced charge carriers. Thus, this study provides a viable idea to solve the problems of poor visible light absorption of BiOCl-based photocatalysts and easy reorganization of electrons and holes in the photocatalysts.
Assuntos
Eletricidade , Oxigênio , Espécies Reativas de Oxigênio , Adsorção , ElétronsRESUMO
Cr(VI) contaminated water usually contains other contaminants like engineered nanomaterials (ENMs). During the process of microbial treatment, the inevitable interaction of Cr(VI), ENMs, and microorganisms probably determines the efficiency of Cr(VI) biotransformation, however, the corresponding information remains elusive. This study investigated the interaction of ZnO nanoparticles (NPs), Cr(VI), and Pannonibacter phragmitetus BB (hereafter BB), which changed the process of microbial Cr(VI) reduction. ZnO NPs inhibited Cr(VI) reduction, but had no effect on bacterial viability. In particular, Cr(VI) induced BB to produce organic acids and to drive Zn2+ dissolution from ZnO NPs inside and outside of cells. The dissolved Zn2+ not only promoted Cr(VI) reduction to Cr(V)/Cr(IV) by strengthening sugar metabolism and inducing increase in NAD(P)H production, but also hindered Cr(V)/Cr(IV) transformation to Cr(III) through down-regulating Cr(VI) reductase genes. A novel bacterial driven ROS scavenging mechanism leading to the inhibition of Cr(VI) reduction was elucidated. Specifically, the accumulated Cr(VI) and Cr(V)/Cr(IV) formed a redox dynamic equilibrium, which triggered the disproportionation of superoxide radicals mimicking superoxide dismutase through the flip-flop of Cr(VI) and Cr(V)/Cr(IV) in bacterial cells. This study provided a realistic insight into design the applicability of biological remediation technology for Cr(VI) contaminant and evaluating environmental risks of ENMs.
Assuntos
Nanopartículas , Nanoestruturas , Óxido de Zinco , Espécies Reativas de Oxigênio , Óxido de Zinco/toxicidade , NADRESUMO
The wide use of plastic film mulch has led to the release of phthalate esters (PAEs), which seriously threatens the soil environment and the safety of crop production. However, it is unknown whether there is a maximum threshold of soil PAEs accumulation induced by plastic film residue, and the dynamic changes of soil PAEs under field conditions are still unclear. To address these issues, a field experiment was conducted to investigate the temporal fluctuations of soil PAEs content and the response of microbial community structure in the field with plastic film residue. Results showed that the content of soil PAEs fluctuated during an observation period of one year, had a periodical peak in winter and summer, and was exacerbated by the increase in the aging degree and residual amount of plastic films. The PAEs content in soil with black films was higher than the US soil allowable criteria. High-throughput sequencing analysis showed that the addition of residual film significantly increased the alpha diversity of bacterial communities, changed the structure of bacterial community, and generated significant disturbances in bacterial function. Besides, the residual film recruited more microbiota related to plastic film and PAEs degradation. Results of the present study provide insight into the dynamic variation of soil PAEs caused by plastic film residue in one year, which is important to help evaluate the pollution risk of PAEs on soils and crops caused by residual plastic film.
Assuntos
Ácidos Ftálicos , Poluentes do Solo , Solo/química , Ácidos Ftálicos/análise , Poluentes do Solo/análise , Verduras/química , Plásticos/química , China , Ésteres/análise , Dibutilftalato/análiseRESUMO
Improving the separation efficiency and transfer ability of photoinduced electrons/holes in pyrite (FeS2)-based photocatalytic materials is significant for the photoreduction of hexavalent chromium (Cr(VI)) but still remains a challenge. Herein, a novel homojunction was prepared through in-situ growth of nickel (Ni) doped FeS2 nanoparticles on FeS2 nanobelts (denoted as Ni-FeS2/FeS2). Systematical characterizations revealed that Ni doped FeS2 nanoparticles have been successfully in situ grown along the lattice of FeS2 nanobelts. Photoreduction experiments demonstrated that the Ni-FeS2/FeS2 homojunction with 2 mmol Ni doping contents (denoted as 2Ni-FeS2/FeS2) exhibited the optimum Cr(VI) reduction efficiency among the studied catalysts. Density Functional Theory (DFT) calculated results verified that Ni doping could not only be advantageous for the formation of sulfur vacancies but also modify the band gap and band structure of FeS2 nanoparticles. Moreover, several doping energy levels caused by Ni doping have also appeared near the Fermi level of FeS2 nanoparticles. The migration paths of electrons and the existence of internal electric field (IEF) in homojunction were further verified by the calculation of work function. To sum up, the doping energy levels and IEF that produced by homojunction played important roles in accelerating the separation efficiency of its photogenerated carriers.