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1.
Environ Sci Technol ; 58(11): 5068-5078, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38446141

RESUMO

Sulfate aerosol is one of the major components of secondary fine particulate matter in urban haze that has crucial impacts on the social economy and public health. Among the atmospheric sulfate sources, Mn(II)-catalyzed SO2 oxidation on aerosol surfaces has been regarded as a dominating one. In this work, we measured the reaction kinetics of Mn(II)-catalyzed SO2 oxidation in single droplets using an aerosol optical tweezer. We show that the SO2 oxidation occurs at the Mn(II)-active sites on the aerosol surface, per a piecewise kinetic formulation, one that is characterized by a threshold surface Mn(II) concentration and gaseous SO2 concentration. When the surface Mn(II) concentration is lower than the threshold value, the reaction rate is first order with respect to both Mn(II) and SO2, agreeing with our traditional knowledge. But when surface Mn(II) concentration is above the threshold, the reaction rate becomes independent of Mn(II) concentration, and the reaction order with respect to SO2 becomes greater than unity. The measured reaction rate can serve as a tool to estimate sulfate formation based on field observation, and our established parametrization corrects these calculations. This framework for reaction kinetics and parametrization holds promising potential for generalization to various heterogeneous reaction pathways.


Assuntos
Poluentes Atmosféricos , Material Particulado , Material Particulado/análise , Óxidos de Enxofre , Sulfatos/análise , Aerossóis , Catálise
2.
Ecotoxicol Environ Saf ; 269: 115739, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38016191

RESUMO

The root-associated microbiome assembly substantially promotes (hyper)accumulator plant growth and metal accumulation and is influenced by multiple factors, especially host species and environmental stress. Athyrium wardii (Hook.) is a phytostabilizer that grows in lead (Pb)-zinc (Zn) mine tailings and shows high root Pb accumulation. However, there remains little information on the assembly of the root-associated microbiome of A. wardii and its role in phytostabilization. A field study investigated the structural and functional variation in the root-associated bacterial microbiome of Athyrium wardii (Hook.) exposed to different levels of contamination in Pb-Zn mine tailings. The root compartment dominated the variation in the root-associated bacterial microbiome but the levels of contaminants showed less impact. Bacterial co-occurrence was enhanced in the rhizosphere soil and rhizoplane but tended to be much simpler in the endosphere in terms of network complexity and connectivity. This indicates that the microbial community assembly of A. wardii was non-random and shaped by root selective effects. Proteobacteria, Chloroflexi, Actinobacteria, Cyanobacteria, and Acidobacteriota were generally the dominant bacterial phyla. The genera Crossiella and Bradyrhizobium were enriched in the rhizosphere and cyanobacterial genera were enriched in the endosphere, demonstrating substantial advantages to plant survival and adaptation in the harsh mine environment. Functional categories involved in amino acid and carbohydrate metabolism were abundant in the rhizosphere soil, thus contributing to metal solubility and bioavailability in the rhizosphere. Membrane transporters, especially ATP-binding cassette transporters, were enriched in the endosphere, indicating a potential role in metal tolerance and transportation in A. wardii. The study shows substantial variation in the structure and function of microbiomes colonizing different compartments, with the rhizosphere and endophytic microbiota potentially involved in plant metal tolerance and accumulation during phytostabilization.


Assuntos
Microbiota , Traqueófitas , Chumbo/toxicidade , Chumbo/metabolismo , Plantas , Bactérias , Zinco/toxicidade , Zinco/metabolismo , Solo/química , Rizosfera , Raízes de Plantas/metabolismo , Microbiologia do Solo
3.
J Environ Sci (China) ; 139: 206-216, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38105048

RESUMO

The aging process of atmospheric aerosols usually leads to a mixture of inorganic salts and organic compounds of anthropogenic origin. In organic compounds, polyhydroxy organic acids are important components, however, the study on composition and hygroscopic properties of the mixture containing inorganics and polyhydroxy organic acids is scanty. In this study, gluconic acid, the proxy of polyhydroxy organic acids, is mixed with the representative nitrate (Mg(NO3)2, Ca(NO3)2) to form aerosols. ATR-FTIR and optical microscopy are employed to study the component changes and hygroscopicity as a function of relative humidity. As relative humidity fluctuates, the FTIR-ATR spectra display that the internal mixed gluconic acid (CH2(CH)4(OH)5COOH) and nitrate can react to release acidic gases, forming relevant gluconate and further affecting the hygroscopicity. The specific presentation is particles cannot be recovered to their original size after the dehydration-hydration process and there will be some disparities in GF for mixed particles. For the gluconic acid-Ca(NO3)2/Mg(NO3)2 mixtures with molar ratios of 1:1, higher degree of reaction resulting in the production of large amounts of gluconate should be responsible to the lower hygroscopicity compared to ZSR model. For 1:2 gluconic acid-nitrate mixed systems (with higher nitrate content), the hygroscopicity of mixtures are higher than the ZSR prediction. A possible reason could be 'salt-promoting effect' on the organic fractions of the surplus inorganic salt in the mixture. These data can improve the chemical composition list evaluation, in turn hygroscopic properties and phase state of atmospheric aerosol, and then the climate effect.


Assuntos
Gluconatos , Nitratos , Molhabilidade , Compostos Orgânicos , Aerossóis/química
4.
Opt Express ; 31(26): 44603-44610, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38178527

RESUMO

In this paper, we report for the first time on an all-multimode fiber spatiotemporal mode-locked figure-eight laser operating at 1.0 µm. This laser utilizes a multimode gain fiber and a nonlinear amplifying loop mirror mechanism. It can generate mode-locked noise-like pulses at different central wavelengths. Additionally, we observed the presence of a multi-soliton state within the cavity by reducing intracavity gain. This study contributes to a broader investigation of various pulse phenomena in spatiotemporal mode-locked lasers and provides valuable insights into further exploring the evolution of spatiotemporal dynamics in such systems.

5.
Environ Sci Technol ; 57(48): 20074-20084, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-37974434

RESUMO

Efflorescence of ammonium nitrate (AN) aerosols significantly impacts atmospheric secondary aerosol formation, climate, and human health. We investigated the effect of representative water-soluble organic compounds (WSOCs) (sucralose (SUC), glycerol (GLY), and citric acid (CA) on AN:WSOC aerosol efflorescence using vacuum Fourier transform infrared spectroscopy. Combining efflorescence relative humidity (ERH) measurements, heterogeneous nucleation rates, and model predictions, we found that aerosol viscosity, correlating with molecular diffusion, effectively predicted ERH variations among the AN:WSOC aerosols. WSOCs with higher viscosity (SUC and CA) hindered efflorescence, while GLY with a lower viscosity showed a minor effect. At a low AN:CA molar ratio (10:1), CA promoted ERH, likely due to CA crystallization. Increasing the droplet pH inhibited AN:CA aerosol efflorescence. In contrast, for AN:SUC and AN:GLY aerosols, efflorescence is pH-insensitive. With the addition of trivial sulfate, AN:SUC droplets exhibited two-stage efflorescence, coinciding with ammonium sulfate and AN efflorescence. Given the atmospheric abundance, the morphology, phase, and mixing state of nitrate aerosols are significant for atmospheric chemistry and physics. Our results suggest that AN:WSOCs aerosols can exist in the amorphous phase in the atmosphere, with efflorescence behavior depending on the aerosol composition, viscosity, pH, and the cation and anion interactions in a complex manner.


Assuntos
Nitratos , Água , Humanos , Nitratos/química , Água/química , Umidade , Sulfato de Amônio/química , Aerossóis , Concentração de Íons de Hidrogênio
6.
J Asthma ; : 1-12, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38078661

RESUMO

Objective: Allergen sensitization and high rates of concomitant allergic diseases are characteristic of severe pediatric asthma. The present study was aimed to explore the mechanism of allergic asthma via bioinformatics and experiment investigation.Methods: The GSE27011 dataset contained the expression profiles of normal and pediatric asthma white blood cells was downloaded for analyzing the different expression genes and function enrichment. The allergic asthma model in infant mice was established by ovalbumin (OVA) stimulation. The cellular model was established by house dust mite (HDM)-stimulation in human bronchial epithelial cells. The absent in melanoma 2 (AIM2) knockdown was achieved by intranasal lentivirus injection or cell infection. The bronchoalveolar lavage fluid (BALF) was collected for cell counting and ELISA assessment of cytokines. Lung tissues were collected for HE staining and immunohistochemical (IHC) staining. Real-time PCR and immunoblotting were used for the determination of key gene expressions in mouse and cell models.Results: upregulation of AIM2 gene expression was observed in pediatric asthma patients based on GSE27011 and OVA-induced infant mouse allergic asthma model. AIM2 knockdown ameliorated OVA caused elevation in airway hyper-responsiveness (AHR), elevation in cell quantities (eosinophils, neutrophils, lymphocytes), and levels of cytokines (IL-4, IL-13, TNF-α, and OVA-specific IgE) in BALF. Moreover, AIM2 knockdown relieved OVA-caused histopathological alterations in mouse lungs, up-regulation of AIM2 levels, and NOD1 and receptor-interacting protein 2 (RIP2) protein levels, as well as p65 phosphorylation. In the cell model, AIM2 knockdown partially ameliorated HDM-induced epithelial dysfunctions by promoting cell viability, down-regulating inflammatory cytokines levels, and decreasing the protein levels of AIM2, NOD1, RIP2, and phosphorylated p65.Conclusion: AIM2 participates in HDM-induced epithelial dysfunctions and OVA-induced allergic asthma progression. AIM2 could be a promising target for pediatric allergic asthma treatment regimens, which warrants further in vivo investigations.

7.
Adv Atmos Sci ; : 1-23, 2023 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-37359906

RESUMO

Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the "air pollution complex" was first proposed by Professor Xiaoyan TANG in 1997. For papers published in 2021 on air pollution (only papers included in the Web of Science Core Collection database were considered), more than 24 000 papers were authored or co-authored by scientists working in China. In this paper, we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years, including studies on (1) sources and emission inventories, (2) atmospheric chemical processes, (3) interactions of air pollution with meteorology, weather and climate, (4) interactions between the biosphere and atmosphere, and (5) data assimilation. The intention was not to provide a complete review of all progress made in the last few years, but rather to serve as a starting point for learning more about atmospheric chemistry research in China. The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established, provided robust scientific support to highly successful air pollution control policies in China, and created great opportunities in education, training, and career development for many graduate students and young scientists. This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances, whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China, to hopefully be addressed over the next few decades.

8.
J Environ Sci (China) ; 127: 320-327, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36522064

RESUMO

The high NO3- concentration in fine particulate matters (PM2.5) during heavy haze events has attracted much attention, but the formation mechanism of nitrates remains largely uncertain, especially concerning heterogeneous uptake of NOX by aqueous phase. In this work, the heterogeneous uptake of NO2 by sodium acetate (NaAc) droplets with different NO2 concentrations and relative humidity (RH) conditions is investigated by microscopic Fourier transform infrared spectrometer (micro-FTIR). The IR feature changes of aqueous droplets indicate the acetate depletion and nitrite formation in humid environment. This implies that acetate droplets can provide the alkaline aqueous circumstances caused by acetate hydrolysis and acetic acid (HAc) volatilization for nitrite formation during the NO2 heterogeneous uptake. Meanwhile, the nitrite formation will exhibit a pH neutralizing effect on acetate hydrolysis, further facilitating HAc volatilization and acetate depletion. The heterogeneous uptake coefficient increases from 5.2 × 10-6 to 1.27 × 10-5 as RH decreases from 90% to 60% due to the enhanced HAc volatilization. Furthermore, no obvious change in uptake coefficient with different NO2 concentrations is observed. This work may provide a new pathway for atmospheric nitrogen cycling and secondary nitrite aerosol formation.


Assuntos
Nitritos , Dióxido de Nitrogênio , Acetato de Sódio , Aerossóis/análise , Material Particulado , Água
9.
Anal Chem ; 94(43): 15132-15138, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36251492

RESUMO

Acidity is a defining property of atmospheric aerosols that profoundly affects environmental systems, human health, and climate. However, directly measuring the pH of aerosol microdroplets remains a challenge, especially when the microdroplets' composition is nonhomogeneous or dynamically evolving or both. As a result, a pH measurement technique with high spatiotemporal resolution is needed. Here, we report a spatiotemporally resolved pH measurement technique in microdroplets using spontaneous Raman spectroscopy. Our target sample was the microdroplets comprising sodium chloride and oxalic acid─laboratory surrogates of sea spray aerosols and water-soluble organic compounds, respectively. Our measurements show that the chloride depletion from the microdroplets caused a continuous increase in pH by ∼0.5 units in 2 hours. Meanwhile, the surface propensity of chloride anions triggers a stable pH gradient inside a single droplet, with the pH at the droplet surface lower than that at the core by ∼ 0.4 units. The uncertainties arising from the Raman detection limit (±0.08 pH units) and from the nonideal solution conditions (-0.06 pH units) are constrained. Our findings indicate that spontaneous Raman spectroscopy is a simple yet robust technique for precise pH measurement in aerosols with high spatiotemporal resolution.


Assuntos
Cloretos , Análise Espectral Raman , Humanos , Aerossóis/química , Análise Espectral Raman/métodos , Água/química , Halogênios , Concentração de Íons de Hidrogênio
10.
Anal Chem ; 94(39): 13311-13314, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36154009

RESUMO

Spontaneous Raman scattering is an attractive optical technique for the analysis of gases and liquids; however, their low densities and notoriously weak scattering cross sections demand an enhancement of the spontaneous Raman scattering signal for detection. Here, we have developed a simple but highly effective and fast technique to enhance the signal of spontaneous Raman scattering from gases and liquids. The technique is developed based on the principle of an integrating sphere, which realizes the multiple pass actions of low-energy pump light and the collection of all Raman scattered light for a sample volume of 2 mL. By measuring the ambient air sample with an exposure time of 180 s, we found the experimental detection limit of our spontaneous Raman scattering setup can reach 3 ppm. CH4 (<2 ppm) in air can be also examined by increasing the exposure time to 300 s. The performance of our setup used for the analysis of trace gases is further illustrated by characterizing ethane, propane, butane, and pentane in methane as well as isotopes of carbon dioxide. The results reveal that the detection limit of our setup for liquids can be improved by nearly 4 orders of magnitude compared to that of confocal Raman scattering spectroscopy with the same experimental conditions.

11.
Anal Chem ; 94(42): 14785-14793, 2022 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-36223308

RESUMO

Antibiotics are powerful tools to treat bacterial infections, but antibiotic pollution is becoming a severe threat to the effective treatment of human bacterial infections. The detection of antibiotics in water has been a crucial research area for bioassays in recent years. There is still an urgent need for a simple ultrasensitive detection approach to achieve accurate antibiotic detection at low concentrations. Herein, a field-effect transistor (FET)-based biosensor was developed using ultraclean graphene and an aptamer for ultrasensitive tetracycline detection. Using a newly designed camphor-rosin clean transfer (CRCT) scheme to prepare ultraclean graphene, the carrier mobility of the FET is found to be improved by more than 10 times compared with the FET prepared by the conventional PMMA transfer (CPT) method. Based on the FET, aptamer-functionalized transistor antibiotic biosensors were constructed and characterized. A dynamic detection range of 5 orders of magnitude, a sensitivity of 21.7 mV/decade, and a low detection limit of 100 fM are achieved for the CRCT-FET biosensors with good stability, which are much improved compared with the biosensor prepared by the CPT method. The antibiotic sensing and sensing performance enhancement mechanisms for the CRCT-FET biosensor were studied and analyzed based on experimental results and a biosensing model. Finally, the CRCT-FET biosensor was verified by detecting antibiotics in actual samples obtained from the entrances of Bohai Bay.


Assuntos
Técnicas Biossensoriais , Grafite , Humanos , Transistores Eletrônicos , Antibacterianos , Polimetil Metacrilato , Cânfora , Técnicas Biossensoriais/métodos , Oligonucleotídeos , Água , Tetraciclinas
12.
Acc Chem Res ; 54(19): 3667-3678, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34569236

RESUMO

Aerosols are ubiquitous in the atmosphere and profoundly affect climate systems and human health. To gain more insights on their broad impacts, we need to comprehensively understand the fundamental properties of atmospheric aerosols. Since aerosols are multiphase, a dispersion of condensed matter (solid particles or liquid droplets, hereafter particles) in gas, partitioning of volatile matter between the condensed and the gas phases is one defining characteristic of aerosols. For example, water content partitioning under different relative humidity conditions, known as aerosol hygroscopicity, has been extensively investigated in the past decades. Meanwhile, partitioning of volatile organic or inorganic components, which is referred to as aerosol volatility, remains understudied. Commonly, a bulk solution system is treated as a single phase, with volatility mainly determined by the nature of its components, and the composition partitioning between solution and gas phase is limited. Aerosols, however, comprise an extensive gas phase, and their volatility can also be induced by component reactions. These reactions occurring within aerosols are driven by the formation of volatile products and their continuous partitioning into the gas phase. As a consequence, the overall aerosol systems exhibit prominent volatility. Noteworthily, such volatility induced by reactions is a phenomenon exclusively observed in the multiphase aerosol systems, and it is trivial in bulk solutions due to the limited extent of liquid-gas partitioning. Take the chloride depletion in sea salt particles as an example. Recent findings have revealed that chloride depletion can be caused by reactions between NaCl and weak organic acids, which release HCl into the gas phase. Such a reaction can be described as a strong acid displaced by a weak acid, which is hardly observed in bulk phase. Generally, this unique partitioning behavior of aerosol systems and its potential to alter aerosol composition, size, reactivity, and other physicochemical properties merits more attention by atmospheric community.This Account focuses on the recent advancements in the research of component reactions that induce aerosol volatility. These reactions can be categorized into four types: chloride depletion, nitrate depletion, ammonium depletion, and salt hydrolysis. The depletion of chloride or nitrate can be regarded as a displacement reaction, in which a strong acid is displaced by a weak acid. Such a reaction releases highly volatile HCl or HNO3 into the gas phase and leads to a loss of chloride or nitrate within the particles. Likewise, ammonium depletion is a displacement reaction in which a strong base is displaced by a weak base, resulting in release of ammonia and substantial changes in aerosol hygroscopicity. In addition, aerosol volatility can also be induced by salt hydrolysis in a specific case, which is sustained by the coexistence of proton acceptor and hydroxide ion acceptor within particles. Furthermore, we quantitatively discuss these displacement reactions from both thermodynamic and kinetic perspectives, by using the extended aerosol inorganic model (E-AIM) and Maxwell steady-state diffusive mass transfer equation, respectively. Given the ubiquity of component partitioning in aerosol systems, our discussion may provide a new perspective on the underlying mechanisms of aerosol aging and relevant climate effects.

13.
Environ Sci Technol ; 56(10): 6274-6281, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35476405

RESUMO

Accurately measuring the pH of atmospheric aerosols is a prerequisite for understanding the multiphase chemistry that profoundly affects the environment and climate systems. Despite the advancements of experimental techniques for in situ pH measurements in aerosols, current studies are limited to measuring the static pH of aerosol microdroplets with an unperturbed composition. This steady-state scenario, however, deviates from the real-world aerosols undergoing atmospheric aging reactions, specifically, those characterized with a spontaneous displacement of strong bases (or acids) with high volatility. Here, we introduce a continuous and in situ measurement of aerosol pH by using a 4-mercaptopyridine-functionalized silver nanoparticle probe and surface-enhanced Raman spectroscopy. We find that the ammonium depletion─a spontaneous displacement of ammonium by dicarboxylic acid salts─continuously acidifies aerosol water over time. The decaying trends of pH in the aerosols under various humidity conditions can be unified with a universal exponential function. Such an exponentially decaying function further indicates that the ammonium depletion reaction is a self-limiting process. Our technique can be applied to study the dynamic change of aerosol acidity during the complex atmospheric aging processes, toward elucidating their implications on atmospheric chloride, nitrate, and ammonium cycles.

14.
Environ Sci Technol ; 56(18): 12937-12944, 2022 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-36049086

RESUMO

Depletion of chloride, nitrate, or ammonium from atmospheric aerosols represents a unique class of displacement reactions in which strong acids (HCl and HNO3) or bases (NH3) are substituted by weaker ones (i.e., dicarboxylic acids or dicarboxylate salts, respectively). These reactions alter the aerosol composition and perturb the atmospheric cycle of volatile compounds, thereby affecting environmental systems and climate. Despite the profound implications, the mechanism of these unique displacement reactions remains unclear. Here, we elucidate the thermodynamics and kinetics of these reactions using the multiphase buffer theory and a diffusion-controlled mass-transfer function, respectively. On the thermodynamic aspect, we find that the effective dissociation constants of the strong acids and bases in aerosols are 2 to 10 orders of magnitude lower than those in bulk solutions. On the kinetic aspect, we find that displacement reactions occur rapidly in aerosol microdroplets with a radius below 10 µm. Within this size range, the characteristic reaction time is always shorter than the lifetime of the aerosols in the atmosphere. Our findings suggest that the unique displacement reactions can significantly modify the composition of atmospheric aerosols, and consequentially, these aerosols may manifest distinct properties unforeseen by the chemistry of homogeneous bulk systems.


Assuntos
Compostos de Amônio , Nitratos , Aerossóis/química , Atmosfera/química , Cloretos , Ácidos Dicarboxílicos/química , Cinética , Nitratos/química , Sais , Termodinâmica
15.
Environ Sci Technol ; 56(12): 7637-7646, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35638231

RESUMO

Severe winter haze events in Beijing and North China Plain are characterized by rapid production of sulfate aerosols with unresolved mechanisms. Oxidation of SO2 by O2 in the absence of metal catalysts (uncatalyzed autoxidation) represents the most ubiquitous SO2 conversion pathway in the atmosphere. However, this reaction has long been regarded as too slow to be atmospherically meaningful. This traditional view was based on the kinetic studies conducted in bulk dilute solutions that mimic cloudwater but deviate from urban aerosols. Here, we directly measure the sulfate formation rate via uncatalyzed SO2 autoxidation in single (NH4)2SO4 microdroplets, by using an aerosol optical tweezer coupled with a cavity-enhanced Raman spectroscopy technique. We find that the aqueous reaction of uncatalyzed SO2 autoxidation is accelerated by two orders of magnitude at the high ionic strength (∼36 molal) conditions in the supersaturated aerosol water. Furthermore, at acidic conditions (pH 3.5-4.5), uncatalyzed autoxidation predominately occurs on droplet surface, with a reaction rate unconstrained by SO2 solubility. With these rate enhancements, we estimate that the uncatalyzed SO2 autoxidation in aerosols can produce sulfate at a rate up to 0.20 µg m-3 hr-1, under the winter air pollution condition in Beijing.


Assuntos
Poluentes Atmosféricos , Dióxido de Enxofre , Aerossóis/química , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Cinética , Material Particulado/análise , Sulfatos/química , Dióxido de Enxofre/análise , Óxidos de Enxofre , Água
16.
J Cell Physiol ; 236(3): 2008-2022, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32853398

RESUMO

Polarized macrophages can be broadly classified into classically activated macrophages (M1) and alternatively activated macrophages (M2) in response to the microenvironment signals. Interferon regulatory factor 1 (IRF1) has been demonstrated to play a critical role in macrophage polarization. However, the mechanisms underlying the regulation of IRF1 expression in macrophage polarization still remain unclear. In this study, IRF1 expression was significantly increased in interferon-γ (IFN-γ) and lipopolysaccharide (LPS)-treated RAW264.7 cells. Moreover, miR-130b-3p was decreased and negatively associated with Irf1 in M1 macrophages. miR-130b-3p repressed M1 polarization by inhibiting IRF1 and subsequently reducing the levels of the targets of IRF1, C-C motif chemokine ligand 5 (CCL5), C-X-C motif chemokine ligand 10 (CXCL10), inducible NO synthase (iNOS), and tumor necrosis factor (TNF). Consistent with these data, overexpressed miR-130b-3p in LPS-treated mice suppressed M1 macrophage polarization in lung macrophages and peritoneal macrophages by inhibiting Irf1 expression and alleviated the inflammation in mouse lung tissues. Furthermore, the predicted binding site between the Irf1 messenger RNA 3'-untranslated region (3'-UTR) and miR-130b-3p was confirmed by the dual-luciferase reporter assay. In conclusion, our research gave the first evidence that miR-130b-3p affected the polarization of M1 macrophages by directly inhibiting Irf1. The miR-130b-3p/IRF1 pathway may be a potential target for regulating macrophage polarization.


Assuntos
Polaridade Celular/genética , Fator Regulador 1 de Interferon/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , MicroRNAs/metabolismo , Regiões 3' não Traduzidas/genética , Animais , Sequência de Bases , Polaridade Celular/efeitos dos fármacos , Quimiocina CCL5/metabolismo , Quimiocina CXCL10/metabolismo , Regulação para Baixo/efeitos dos fármacos , Inflamação/genética , Inflamação/patologia , Fator Regulador 1 de Interferon/genética , Interferon gama/farmacologia , Lipopolissacarídeos/farmacologia , Pulmão/patologia , Macrófagos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Células RAW 264.7 , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética
17.
Arterioscler Thromb Vasc Biol ; 40(2): 323-334, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31852218

RESUMO

OBJECTIVE: Deep venous thrombosis (DVT), one of the most common venous thromboembolic disorders, is closely linked with pulmonary embolism and post-thrombotic syndrome, both of which have a high mortality. However, the factors that trigger DVT formation are still largely unknown. Elevated expression of IL (interleukin)-6-an important inflammatory cytokine-has been linked with DVT formation. However, the molecular mechanisms leading to the elevated IL-6 in DVT remain unclear. Here, we proposed that epigenetic modification of IL-6 at the post-transcriptional level may be a crucial trigger for IL-6 upregulation in DVT. Approach and Results: To explore the association between microRNAs and IL-6 in DVT, we performed microRNA microarray analysis and experiments both in vitro and in vivo. Microarray and quantitative real-time polymerase chain reaction results showed that IL-6 expression was increased while miR-338-5p level was decreased substantially in peripheral blood mononuclear cells of patients with DVT, and there was significant negative correlation between miR-338-5p and IL-6. Experiments in vitro showed that overexpressed miR-338-5p reduced IL-6 expression, while miR-338-5p knockdown increased IL-6 expression. Moreover, our in vivo study found that mice with anti-IL-6 antibody or agomiR-338-5p delivery resulted in decreased IL-6 expression and alleviated DVT formation, whereas antagomiR-338-5p acted inversely. Most of miR-338-5p was found located in cytoplasm by fluorescence in situ hybridization. Dual-luciferase reporter assay identified direct binding between miR-338-5p and IL-6. CONCLUSIONS: Our results suggest that decreased miR-338-5p promotes DVT formation by increasing IL-6 expression.


Assuntos
Regulação da Expressão Gênica , Interleucina-6/genética , Extremidade Inferior/irrigação sanguínea , MicroRNAs/genética , Trombose Venosa/genética , Angiografia , Animais , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Interleucina-6/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/biossíntese , Pessoa de Meia-Idade , RNA/genética , Estudos Retrospectivos , Ultrassonografia Doppler em Cores , Trombose Venosa/diagnóstico , Trombose Venosa/metabolismo
18.
J Phys Chem A ; 125(7): 1589-1597, 2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33576639

RESUMO

The Hofmeister effect of inorganic ions to precipitate proteins has been used to understand the coagulation phenomenon in colloid and protein science. Herein, for the first time, this effect is studied on the hygroscopicity of aerosols using ATR-FTIR spectroscopy. The representative Hofmeister salts (MgSO4, KCl, NH4NO3) and amino acid (glycine) with different amino acid/salt molar ratios (ASRs) are mixed and atomized into micrometer-sized particles. For mixed kosmotrope (MgSO4)/glycine and chaotrope (NH4NO3)/glycine with an ASR of 1:1, both ERHs (efflorescence relative humidities) and DRHs (deliquescence relative humidities) are absent. However, for the mixtures of glycine and neutral salt (KCl), no DRH is observed while 66.2 and 61.4% ERH of glycine is detected for mixtures with ASRs of 1:1 and 1:3, respectively, which is similar to pure glycine. For the mixture of NH4NO3/glycine with an ASR of 1:3, ERH and DRH are found to be 15.4 and 32.2% RH, less than that of pure NH4NO3. Further, interactions between glycine-salt and/or water is also studied in the mixtures during hydration and dehydration. Water-mediated ion-glycine interaction is detected based on the two glycine bands merging into one band. Glycine-SO42- interaction is present for glycine/sulfate in all ASRs, while glycine-NO3- interaction is only seen for 1:3 glycine/NH4NO3 mixtures during hydration. This work opens a window to understand the Hofmeister effect on the hygroscopicity of atmospheric aerosols.

19.
Adv Physiol Educ ; 45(2): 333-341, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33886395

RESUMO

In higher education, it is a great challenge for instructors to teach international medical students (IMSs) efficiently. These students usually have different learning obstacles and learning style preferences from domestic students. Thus it is necessary to use teaching modalities targeting the specific characteristics of IMSs. Accordingly, we have developed a teaching modality composed of classical teacher-centered approach (TCA), enriched with components of student-centered approach (SCA) and online interactions targeting the learning characteristics of IMSs, which we defined as TESOT (an acronym made of the underlined words' initials). Aside from the online interactions that provide both answers to questions raised by students and guidance throughout a course, this modality contains additional in-classroom components (i.e., pre-lecture quiz, student-led summary, and post-lecture quiz). The effectiveness of this modality was tested in the nervous system module of the Physiology course for IMSs. The final exam scores in the nervous system module in the year taught with TESOT were higher than those earned by students taught with a classical TCA modality in preceding 2 yr. The improvement of teaching effectiveness is attributable to increasing communication, bridging course contexts, and meeting diverse learning style preferences. These results indicate that TESOT as an effective teaching modality is useful for enhancing efficiency of teaching IMSs.


Assuntos
Educação Médica , Estudantes de Medicina , Currículo , Avaliação Educacional , Humanos , Aprendizagem , Ensino
20.
J Mol Cell Cardiol ; 144: 97-108, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32445843

RESUMO

BACKGROUND: Deep venous thrombosis (DVT) is one of the most common venous thromboembolic (VTE) disorders and the third leading cardiovascular complication. Accumulating evidence has shown that decreased interleukin-10 (IL-10) was involved in DVT. However, the underlying molecular mechanisms are still largely unknown. Here, we proposed that the epigenetic modification of IL-10 at the post-transcriptional level may be a crucial trigger for IL-10 down-regulation in DVT. METHODS: miRNA expression in DVT was profiled by miRNA microarray analysis. The upstream miRNA regulators of IL-10 were predicted by in silico target prediction tools. The expression of IL-10 mRNA and miR-374b-5p were examined by quantitative real-time PCR (qRT-PCR) and the protein expression of IL-10 was detected by enzyme-linked immunoassay. Dual luciferase reporter assay was used to identify the interaction between miR-374b-5p and IL10. A murine model of DVT was developed and the localization of miR-374b-5p was visualized in vitro by fluorescence in situ hybridization. The biological effects of miR-374b-5p on IL-10 was examined both in vitro and in vivo. RESULTS: Microarray and qRT-PCR results showed that the IL-10 expression was decreased while miR-374b-5p level was increased substantially in peripheral blood mononuclear cells of DVT patients, and there was significant negative correlation between miR-374b-5p and IL-10. Experiments in vitro showed that overexpressed miR-374b-5p reduced IL-10 expression, while miR-374b-5p knockdown increased IL-10 expression. Moreover, in vivo studies revealed that DVT mice with anti-IL-10 antibody or agomiR-374b-5p delivery resulted in decreased IL-10 expression and aggravated DVT formation, whereas antagomiR-374b-5p acted inversely. Dual luciferase reporter assay identified direct binding between miR-374b-5p and IL10. CONCLUSIONS: These findings suggest that increased miR-374b-5p promotes DVT formation by downregulating IL-10 expression. miR-374b-5p may be explored as a promising diagnostic marker and therapeutic target for DVT.


Assuntos
Regulação da Expressão Gênica , Interleucina-10/genética , MicroRNAs/genética , Interferência de RNA , Trombose Venosa/etiologia , Regiões 3' não Traduzidas , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Endotélio , Técnicas de Silenciamento de Genes , Genes Reporter , Células Endoteliais da Veia Umbilical Humana , Humanos , Imuno-Histoquímica , Camundongos , Ultrassonografia , Trombose Venosa/sangue , Trombose Venosa/diagnóstico , Trombose Venosa/metabolismo
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