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1.
Cell Mol Life Sci ; 81(1): 39, 2024 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-38214751

RESUMEN

Colorectal cancer (CRC) is characterized by a complex tumor inflammatory microenvironment, while angiogenesis and immunosuppression frequently occur concomitantly. However, the exact mechanism that controls angiogenesis and immunosuppression in CRC microenvironment remains unclear. Herein, we found that expression levels of lipid raft protein STOML2 were increased in CRC and were associated with advanced disease stage and poor survival outcomes. Intriguingly, we revealed that STOML2 is essential for CRC tumor inflammatory microenvironment, which induces angiogenesis and facilitates tumor immune escape simultaneously both in vitro and in vivo. Moreover, tumors with STOML2 overexpression showed effective response to anti-angiogenesis treatment and immunotherapy in vivo. Mechanistically, STOML2 regulates CRC proliferation, angiogenesis, and immune escape through activated NF-κB signaling pathway via binding to TRADD protein, resulting in upregulation of CCND1, VEGF, and PD-L1. Furthermore, treatment with NF-κB inhibitor dramatically reversed the ability of proliferation and angiogenesis. Clinically, we also observed a strong positive correlation between STOML2 expression and Ki67, CD31, VEGFC and PD-1 of CD8+T cell expression. Taken together, our results provided novel insights into the role of STOML2 in CRC inflammatory microenvironment, which may present a therapeutic opportunity for CRC.


Asunto(s)
Neoplasias Colorrectales , Proteínas de la Membrana , FN-kappa B , Microambiente Tumoral , Humanos , Línea Celular Tumoral , Neoplasias Colorrectales/metabolismo , FN-kappa B/metabolismo , Transducción de Señal , Regulación hacia Arriba , Microdominios de Membrana , Proteínas de la Membrana/genética
2.
Front Microbiol ; 14: 1131178, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37180277

RESUMEN

Although the potent antibacterial ability of radezolid against Staphylococcus aureus has been widely reported worldwide, its antibacterial and anti-biofilm activity against the S. aureus clinical isolates from China remains elusive. In this study, the minimum inhibitory concentration (MIC) of radezolid was determined in S. aureus clinical isolates from China using the agar dilution method, and the relationship between radezolid susceptibility and ST distribution was also investigated. The anti-biofilm activity of radezolid against S. aureus was determined by a crystal violet assay and compared with that of linezolid and contezolid. The quantitative proteomics of S. aureus treated with radezolid was analyzed, and the genetic mutations in radezolid-induced resistant S. aureus were determined by whole-genome sequencing. The dynamic changes in transcriptional expression levels of several biofilm-related genes were analyzed by quantitative RT-PCR. Our data showed that radezolid MIC ranged from ≤0.125 to 0.5 mg/L, which was almost 1/4 × MIC of linezolid against S. aureus, indicating the greater antibacterial activity of radezolid than linezolid. The S. aureus clinical isolates with radezolid MICs of 0.5 mg/L were most widely distributed in ST239 of MRSA and ST7 of MSSA. Moreover, the more robust anti-biofilm activity of radezolid with subinhibitory concentrations (1/8 × MIC and 1/16 × MIC) was demonstrated against S. aureus when compared with that of contezolid and linezolid. Genetic mutations were found in glmS, 23S rRNA, and DUF1542 domain-containing protein in radezolid-induced resistant S. aureus selected by in vitro induction of drug exposure. Quantitative proteomic analysis of S. aureus indicated that the global expression of some biofilm-related and virulence-related proteins was downregulated. Quantitative RT-PCR further confirmed that the expressions of some downregulated biofilm-related proteins, including sdrD, carA, sraP, hlgC, sasG, spa, sspP, fnbA, and oatA, were decreased after 12 h and 24 h of exposure to radezolid. Conclusively, radezolid shows robust antibacterial and anti-biofilm activity against S. aureus clinical isolates from China when compared with contezolid and linezolid.

3.
BMC Cancer ; 23(1): 473, 2023 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-37221488

RESUMEN

BACKGROUND: The contributive role of the microbiome in tumor progression has been reported in multiple studies, such as the Fusobacterium nucleatum (F. nucleatum) in breast cancer (BC). This study aimed to explore the role of F. nucleatum-derived small extracellular vesicles (Fn-EVs) in BC and preliminarily uncover the mechanism. METHODS: Ten normal and 20 cancerous breast tissues were harvested to investigate the gDNA expression of F. nucleatum and its relation with the clinical characteristics of BC patients. After isolating Fn-EVs by ultracentrifugation from F. nucleatum (ATCC 25,586), both MDA-MB-231 and MCF-7 cells were treated with PBS, Fn, or Fn-EVs, followed by being subjected to CCK-8, Edu staining, wound healing, and Transwell assays to detect their cell viability, proliferation, migration, and invasion. TLR4 expression in BC cells with diverse treatments was assessed by western blot. In vivo experiments were performed to verify its role in tumor growth and liver metastasis. RESULTS: The F. nucleatum gDNA levels of breast tissues in BC patients were significantly higher than those in normal subjects, and positively associated with tumor size and metastasis. Fn-EVs administration significantly enhanced the cell viability, proliferation, migration, and invasion of BC cells, while knocking down TLR4 in BC cells could block these effects. Furthermore, in vivo study verified the contributive role of Fn-EVs in tumor growth and metastasis of BC, which might rely on its regulation of TLR4. CONCLUSIONS: Collectively, our results suggest that F. nucleatum plays an important role in BC tumor growth and metastasis by regulating TLR4 through Fn-EVs. Thus, a better understanding of this process may aid in the development of novel therapeutic agents.


Asunto(s)
Neoplasias de la Mama , Vesículas Extracelulares , Fusobacterium nucleatum , Receptor Toll-Like 4 , Metástasis de la Neoplasia , Neoplasias de la Mama/patología , Humanos , Línea Celular Tumoral , Receptor Toll-Like 4/metabolismo , Masculino , Animales , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos
4.
J Colloid Interface Sci ; 643: 247-255, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37060700

RESUMEN

Solar-driven steam generation (SSG) is regarded as a feasible solution to the problem of fresh water scarcity. Although several attempts have been devoted to increase the efficiency of solar-to-steam conversion, it remains difficult to fabricate cost-effective, steady, and multi-angle sunlight-absorbing evaporators from readily available biomass materials. Herein, a novel hierarchical structured SSG evaporator (PDA@Shell-NaClO) is developed through a simple, low-cost, and scalable etching treatment on discarded sea urchin (SU) shells. Attributing to the dedicatedly designed microneedles array structure and porous skeleton structure of the SU shell, this PDA@Shell-NaClO evaporator shows an outstanding average light absorption performance (>90%) in a broad range of angles from 0° to 60° and exceedingly high evaporation rate of 2.81 kg m-2 h-1 under one sun condition. Furthermore, the prepared evaporator also maintains an overall stable evaporation performance and exhibits an excellent durability for a long time of up to two weeks in actual seawater. This full-ocean biomass-based SSG evaporator with plentiful raw material availability offers innovative opportunities for large-scale fresh water production.

5.
Health Secur ; 21(2): 122-129, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36867151

RESUMEN

Public health problems caused by the high transmission of multidrug-resistant organisms (MDROs) have attracted widespread international attention. However, studies on healthy adults in this field are scarce. In this article, we report the microbiological screening results of 180 healthy adults recruited from 1,222 participants between 2019 and 2022 in Shenzhen, China. Findings show a high MDRO carriage rate of 26.7% in those individuals who did not use any antibiotics in the past 6 months and had not been hospitalized within the past year. MDROs were mainly extended-spectrum ß-lactamase-producing Escherichia coli with high resistance to cephalosporin. With the assistance of metagenomic sequencing technology, we also performed long-term observations of several participants and found that drug-resistant gene fragments were prevalent even when MDROs were not detected by drug sensitivity testing. Based on our findings, we suggest that healthcare regulators limit the medical overuse of antibiotics and enact measures to limit its nonmedical use.


Asunto(s)
Antibacterianos , Farmacorresistencia Bacteriana Múltiple , Humanos , Adulto , Prevalencia , Farmacorresistencia Bacteriana Múltiple/genética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Cefalosporinas , China/epidemiología
6.
Virulence ; 13(1): 1920-1927, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36308002

RESUMEN

Acinetobacter baumannii has emerged as a common cause of bloodstream infections, which is associated with high mortality and long periods of hospitalization. To advance the medical care of our patients, the study was designed to identify microbial characteristics associated with poor clinical outcomes. A collection of 32 A. baumannii bloodstream isolates with diverse genetic backgrounds (as determined by multilocus sequence typing) was studied. These isolates were recovered by unique patients (18 males, 14 females; age range: 17 days to 87 years) between 2011 and 2018. A sequential screening approach (cross-referencing analyses using different endpoints) was used to identify isolates with the best correlation between bacterial virulence and clinical prognosis. Isolates associated with more rapid in vitro growth rate, shorter median survival time in pre-clinical infection models, and hospital mortality were selected as candidates for high virulence, while those with opposite characteristics were selected as controls with low virulence. Whole genome sequencing was undertaken in the most promising clinical isolates. We found five virulence genes (beta-hemolysin/cytolysin, Cpi-1a + Cpi-1 (SPI-1 like), enhanced entry proteins, FbpABC, Paa) and 1 secretory system (T6SS) only present in a highly virulent isolate (AB23), compared to a low virulence control isolate (AB6). These genetic elements could be associated with the poor prognosis of A. baumannii bacteraemia and further investigations are warranted.


Asunto(s)
Infecciones por Acinetobacter , Acinetobacter baumannii , Bacteriemia , Femenino , Humanos , Recién Nacido , Masculino , Infecciones por Acinetobacter/microbiología , Antibacterianos/farmacología , Bacteriemia/microbiología , Farmacorresistencia Bacteriana Múltiple/genética , Genómica , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Virulencia/genética
7.
J Antibiot (Tokyo) ; 75(9): 498-508, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35896611

RESUMEN

Eravacycline (Erava) is a synthetic fluorocycline with potent antimicrobial activity against a wide range of Gram-positive bacteria. This study aimed to investigate the in vitro antimicrobial activity and resistance mechanism of Erava in clinical E. faecium isolates from China. Erava minimum inhibitory concentrations (MICs) against clinical E. faecium isolates-including those resistant to linezolid (LZD) or harboring the tetracycline (Tet) resistance genes was ≤0.25 mg l-1. Moreover, our data indicated that clinical isolates of E. faecium with Erava MIC 0.25 mg l-1 were predominantly shown to belong to Sequence-type 78 (ST78) and ST80. The prevalence of Erava heteroresistance in clinical E. faecium strain was 2.46% (3/122). The increased Erava MIC values of heteroresistance-derived E. faecium clones could be significantly reduced by efflux pump inhibitors (EPIs). Furthermore, comparative proteomics results showed that efflux pumps lmrA, mdlA, and mdlB contributed significantly to the acquisition of Erava resistance in E. faecium. In addition, a genetic mutation in 16 S rRNA (G190A) were detected in resistant E. faecium isolates induced by Erava. In summary, Erava exhibits potent in vitro antimicrobial activity against E. faecium, but mutation of Tet target sites and elevated expression of efflux pumps under Erava selection results in Erava resistance.


Asunto(s)
Enterococcus faecium , Infecciones por Bacterias Grampositivas , Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Enterococcus faecalis , Humanos , Pruebas de Sensibilidad Microbiana , Tetraciclinas/farmacología
8.
Comput Intell Neurosci ; 2022: 7636983, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35510054

RESUMEN

This study aimed to evaluate the activity, resistance, clonality of MIC distribution, and the correlation between virulence and resistance genes and biofilm formation of omadacycline (OMC) in clinics for Streptococcus agalactiae isolates from China. 162 isolates were collected retrospectively in China. The S. agalactiae were collected from the body's cervical secretions, wound secretions, ear swabs, secretions, semen, venous blood, cerebrospinal fluid, pee, etc. The MIC of OMC against S. agalactiae was determined by broth microdilution. The inhibition zone diameters of OMC and other common antibiotics were measured using filter paper. D-test was performed to determine the phenotype of cross resistance between erythromycin and clindamycin. In Multilocus sequence typing (MLST), some commonly-detected resistance genes and virulence gene of these S. agalactiae isolates were investigated using polymerase chain reaction (PCR). Biofilms were detected by crystal violet staining. Our data demonstrated the correalation of the biofilm formation and OMA antimicrobial susceptibility of S.agalactiae clinical isolates with the carrier of virulence gene scpB. Conclusively, OMC exhibits the robust antimcirobial activity against clinical S. agalactiae isolates from China compared with DOX or MIN, and the carrier of the virulence gene scpB might correlate with the biofilm formation in OMC-resistant S. agalactiae.


Asunto(s)
Biopelículas , Streptococcus agalactiae , China , Tipificación de Secuencias Multilocus , Estudios Retrospectivos , Streptococcus agalactiae/genética , Tetraciclinas , Virulencia/genética
9.
Environ Sci Pollut Res Int ; 29(25): 38143-38160, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35067887

RESUMEN

Owing to limitations in monitoring technologies, monitoring the algae content index of water has lagged behind the conventional water quality index. As a result, sample monitoring in many rivers has been too sparse, and the monitoring data have been inconsistent; thus the evolution of water eutrophication has not been fully reflected. This study focused on the middle and lower reaches of the Hanjiang River, China, and correlated moderate-resolution imaging spectroradiometer (MODIS) remote sensing data with measured chlorophyll-a concentrations. Algorithm settings for chlorophyll-a inversion in the middle and lower reaches of the Hanjiang River were established via the trial and error method. The algorithm model for the middle and lower reaches of the Hanjiang River chlorophyll-a concentration inversion, and the results of the inversion analysis for the spatiotemporal evolution characteristics were subsequently used to determine the influence of various environmental factors on changes in the chlorophyll-a concentration. The results indicate that (1) the band combinations B7/(B6 + B5), B7/B5, B4-B2, and B4/(B3 + B2) are well-correlated with the chlorophyll-a concentration; (2) the back propagation (BP) neural network model inversion achieved a better fit and more accurate inversion results than the band ratio model; (3) temporally, algal outbreaks were mostly concentrated occurring in February and March, with higher chlorophyll-a concentrations in the water column during 2000, 2006, 2007, and 2008; (4) spatially, high chlorophyll-a concentrations were observed in the Zhongxiang, the Shayang, and upper Xiantao sections; and (5) increases in the water temperature and decreases in the water level and flow rate could lead to higher chlorophyll-a concentrations; similarly, nutrient salts were identified to be a major factor contributing to changes in the chlorophyll-a concentrations.


Asunto(s)
Monitoreo del Ambiente , Ríos , China , Clorofila/análisis , Clorofila A/análisis , Monitoreo del Ambiente/métodos , Eutrofización
10.
Opt Express ; 29(16): 24684-24694, 2021 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-34614819

RESUMEN

In this paper, two-dimensional material Sb2Te3 nanosheets are fabricated and the optical nonlinear response is investigated. A laser diode (LD) end-pumped doubly Q-switched Tm:YAP laser with electro-optic modulator (EOM) and Sb2Te3 nanosheets based saturable absorber (SA) is presented. The shortest pulse duration of 38 ns is achieved at the pulse repetition frequency of 100 Hz, corresponding to the highest peak power of 111.8 kW. The double Q-switching technique shows the advantages of pulse duration compression and peak power improvement. The coupled rate equations for the doubly Q-switched laser are developed and the corresponding numerical simulation agrees with the experimental results. We believe that the Sb2Te3 is a potential nanomaterial for the application in optoelectronic field.

11.
Nanomaterials (Basel) ; 11(10)2021 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-34685046

RESUMEN

In the current study, layered metallic vanadium disulfide (VS2) is fabricated by a liquid-phase exfoliation method, and its microstructures as well as optical characteristics are investigated. Based on first-principles calculations, the band structure and density of the states of both bulk T-VS2 and monolayer H-VS2 are illustrated, showing the metallic behavior with a zero band gap. By using VS2 as the saturable absorber in a doubly Q-switched Tm:YAP laser with an EOM, the Q-switching laser pulses at 2 µm with 22 ns and 200 Hz are generated, corresponding to the single pulse energy of 755 µJ and the peak power of 34.3 kW. The coupled rate equations of the doubly Q-switched laser are given, and the numerical simulations agree with the experimental results. The results indicate that VS2 is a promising nanomaterial due to its nonlinear optical property. The doubly Q-switched laser demonstrates a high level of performance in reducing pulse width and enhancing pulse peak power.

12.
Nanotechnology ; 32(37)2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-34107461

RESUMEN

In this paper, the Nb2CTxMXene nanosheets were fabricated and the corresponding microstructures were investigated. The nonlinear optical response was illustrated by open aperture Z-scan and I-scan methods. The ground and the excited state absorption cross-sections of 2D Nb2CTxMXene were also investigated. As the saturable absorber (SA), the Nb2CTxMXene was applied in the passively Q-switched Tm:YAP laser. 1.96µs Q-switched pulses with 3.97 W peak power were achieved at the repetition frequency of 80 kHz. Further theoretical model was built by using the coupled rate equations in simulating the dynamic process of the passively Q-switched Tm:YAP laser. The numerical simulation results are fundamentally in agreement with the experimental results, which proves the Nb2CTxMXene can be a good potential nanomaterial for further optoelectronic applications.

13.
Environ Sci Pollut Res Int ; 28(16): 19851-19865, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33410040

RESUMEN

Algal blooms usually occur in semi-closed water bodies such as lakes or estuaries; however, it has occurred frequently in the mid-downstream of the Han River (MSHR) in China since the 1990s. We made a comparative analysis of the hydrological conditions and identified the hydrological condition thresholds that induce algal blooms. From the hydrodynamic point of view, the changes and characteristics of the hydrological conditions in the MSHR were analyzed. Furthermore, the influence on the risk of algal blooms under different design water transfer schemes for the middle route of the South-to-North Water Diversion Project (SNWDP) was studied. The results indicated that (1) the flow in the MSHR less than 900 m3/s and water level in the Yangtze River higher than 14 m provided a suitable hydrological environment for diatoms multiply. (2) The flow of the MSHR showed a downtrend, while the water level of the Yangtze River showed an uptrend. There were variations in hydrological processes. Through specific IHA index analysis, the fact of flow reduction in the MSHR was demonstrated, and further indicated that algal bloom outbreak was in low flow period. (3) The water transfer in the middle route of SNWDP affected the risk probability of algal blooms. The more the amount of water transfer, the greater the risk probability of algal blooms. It was the Water Diversion Project from Yangtze River to Han River (WDPYHR) that replenished flow of the MSHR and was conducive to the prevention and control of algal bloom risk.


Asunto(s)
Monitoreo del Ambiente , Eutrofización , China , Hidrología , Ríos
14.
Appl Opt ; 59(27): 8066-8070, 2020 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-32976383

RESUMEN

Titanium carbide (TiC) nanosheets of two-dimensional multilayer structure were prepared by the liquid-phase exfoliation method. By using the TiC as a saturable absorber, a stable passively Q-switched Er:Lu2O3 laser at 2.85 µm was realized. Under an absorbed pump power of 7.32 W, the obtained maximum output power was 896 mW with a slope efficiency of 15.6%. The Q-switched pulse duration was measured to be 266.8 ns with repetition rates of 136.9 kHz, corresponding to a peak power of 24.6 W.

15.
Microb Pathog ; 149: 104502, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32947016

RESUMEN

AIMS: The aims of this study were to compare the antimicrobial efficacy of Eravacycline (Erava) versus tigecycline (Tig) in vitro against clinical isolates of S. agalactiae from China and further to evaluate the heteroresistance risk and resistance mechanisms of Erava. METHODS: 162 clinical isolates of S. agalactiae were collected retrospectively and the minimal inhibitory concentrations (MICs) of Erava and Tig were determined by agar dilution. Moreover, Tetracycline (Tet) specific resistance genes, genetic mutations in Tet target sites, and sequence types (ST) profiles of clinical isolates of S. agalactiae were investigated with polymerase chain reaction (PCR) experiments. The heteroresistance frequency of Erava and Tig in S. agalactiae was analyzed by population analysis profiling. Furthermore, the resistance mechanisms of both Erava and Tig were investigated in antibiotic-induced resistant S. agalactiae isolates in vitro. RESULTS: The MIC values of Erava and Tig were shown with ≤0.25 mg/L and ≤0.5 mg/L, respectively, against clinical S. agalactiae isolates, including that harboring the Tet-specific resistance genes tet(K), tet(M), or tet(O). The heteroresistance frequency of Tig among the clinical isolates of S. agalactiae was 1.84% (3/162), whereas no positive Erava heteroresistance was found. The enhanced MIC values of both Erava and Tig in the heteroresistance-derivative S. agalactiae clones could be reversed by the efflux pump inhibition experiments. Genetic mutations affecting 30S ribosome units (16SrRNA copies or 30S ribosome protein S10) could result in the cross resistance toward Erava and Tig in the antibiotic-induced resistant S. agalactiae isolates in vitro. CONCLUSIONS: Erava MIC values were nearly half of that of Tig against the clinical isolates of S. agalactiae from China and genetic mutations in the 30S ribosome units of Tet target sites (16SrRNA copies or 30S ribosome protein S10) participated in the resistance evolution of both Erava and Tig under the antibiotic pressure.


Asunto(s)
Streptococcus agalactiae , Tetraciclinas , Antibacterianos/farmacología , China , Farmacorresistencia Bacteriana/genética , Pruebas de Sensibilidad Microbiana , Estudios Retrospectivos , Streptococcus agalactiae/genética , Tetraciclinas/farmacología , Tigeciclina/farmacología
16.
Opt Lett ; 45(15): 4256-4259, 2020 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-32735274

RESUMEN

In this Letter, we report a titanium nitride (Ti4N3Tx) passive Q-switched Er:Lu2O3 laser. The homemade two-dimensional Ti4N3Tx saturable absorber shows excellent passive Q-switching performance around a 2.85 µm wavelength region. Under the absorbed pump power of 7.4 W, the passive Q-switching laser yields a maximum output power of 0.778 W at a pulse repetition rate of 113.7 kHz, corresponding to a single pulse energy of 6.84 µJ and peak power of 24.57 W.

17.
Opt Express ; 28(11): 16893-16899, 2020 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-32549502

RESUMEN

We report the first passive Q-switching operation at 1.95 µm utilizing the disordered Tm:CaLu0.1Gd0.9AlO4 (Tm:CLGA) crystal and the hematite (α-Fe2O3) nanosheets as the saturable absorber. The nonlinear saturable absorption properties of the hematite nanosheets were investigated by the conventional Z-scan technology. The modulation depth of 14.3% with the low saturation intensity of 205 kW/cm2 was obtained, indicating that the hematite could be a suitable saturable absorber for the mid-infrared pulse generation. Using the disordered Tm:CLGA crystal as the gain medium, the passive Q-switching operation could be realized with the hematite nanosheets as the saturable absorber, producing the shortest pulse duration of 402 ns with a repetition rate of 76 kHz. The experimental results convinced us that the hematite nanosheets could be of great interest in the optical pulse generation in the mid-infrared region.

18.
Environ Sci Pollut Res Int ; 27(29): 36295-36305, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32556980

RESUMEN

The widespread use of synthetic polymers has made microplastic (MP) a new type of contaminant that has attracted worldwide attention. Studies have shown that wastewater treatment plants (WWTPs) are an important source of MP collection in the natural environment. This study investigated the removal efficiency and migration characteristics of MPs by sampling the sewage from each treatment section of a WWTP in Zhengzhou, China. The results showed that the abundance of MPs in the influent water and primary, secondary, and tertiary treatment discharges was 16.0, 10.3, 4.5, and 2.9 MP/L, respectively, and the total removal rate of MPs from the influent to the final effluent reached 81.9%. The MPs in the WWTP were mainly small-sized (0.08-0.55 mm), followed by medium-sized (0.55-1.7 mm). Fibers were the dominant MP shape in both the water and sediment samples. Black (36%) and red (23%) were the dominant MP colors. Six different polymer types of MPs were detected, which were mainly polypropylene followed by polyethylene. In general, for the MPs in the WWTP, the removal rate of fragments can reach 97.08%, which is better than that of fibers (70.50%); the removal rate of small-sized can reach 95.86%, which is better than that of medium-sized (83.53%) and large-sized (70.00%). In this study, primary treatment has better effects in eliminating fragments and large-sized MPs; secondary treatment has better effects in eliminating fibers and small-sized MPs. Although WWTPs have a very good removal effect on MPs, 870 million MP/d are still discharged into nearby rivers from WWTPs with a treatment scale of 300,000 m3/day. Graphical Abstract.


Asunto(s)
Aguas Residuales , Contaminantes Químicos del Agua/análisis , China , Monitoreo del Ambiente , Microplásticos , Plásticos , Eliminación de Residuos Líquidos
19.
Nanotechnology ; 31(19): 195703, 2020 May 08.
Artículo en Inglés | MEDLINE | ID: mdl-32081839

RESUMEN

The colloidal CdSe/ZnS quantum dots (QDs) in the PMMA polymer film with different QDs concentrations were fabricated. The influence of QDs concentration and excitation pump energy on nonlinear optical (NLO) properties of PMMA capped CdSe/ZnS QDs was investigated by the Z-scan technique with nanosecond laser pulses in the near-infrared spectral band. A large effective nonlinear absorption coefficient (ß eff  âˆ¼ -10-13 esu) due to the saturable absorption was observed. It was found that the appropriate concentration could lead to the reinforcement of NLO effect. In addition, the impact of the excitation energy on the nonlinear refractive index n 2, real and imaginary parts of the third-order nonlinear optical susceptibility was also performed. This study involving the light-matter interactions in the colloidal quantum dots will benefit potential NLO-based applications of optoelectronics, optical modulation and photonics.

20.
Appl Opt ; 58(30): 8194-8199, 2019 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-31674489

RESUMEN

Few-layered ${{\rm MoSe}_2}$MoSe2 nanosheets were prepared by the low-cost, simple liquid-phase exfoliation method. The ${{\rm MoSe}_2}$MoSe2 nanosheets possessed the modulation depth of 16.5% with a saturation intensity of ${0.84}\;{{\rm MW/cm}^2}$0.84MW/cm2 at 1.34 µm, indicating the performance as the saturable absorber. The passively $Q$Q-switched c-cut ${\rm Nd}:{{\rm GdVO}_4}$Nd:GdVO4 laser at 1.34 µm was demonstrated with the few-layered ${{\rm MoSe}_2}$MoSe2 saturable absorber for the first time. The minimum pulse duration of 420 ns at a repetition rate of 238 kHz could be obtained. In order to significantly reduce the pulse duration, dual-loss modulation simultaneously using both ${{\rm V}^{3 + }}:{\rm YAG}$V3+:YAG and ${{\rm MoSe}_2}$MoSe2 saturable absorbers was implemented. The pulse duration was compressed to a 82.4 ns pulse at a repetition rate of 409.3 kHz at the pump power of 10.66 W. The experimental results provide a solid fundament for the short pulse generation with ${{\rm MoSe}_2}$MoSe2 saturable absorber at 1.34 µm.

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