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1.
Diabetes Metab Syndr Obes ; 17: 903-911, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38414866

RESUMO

Objective: The purpose of the study was to investigate the expression levels and correlation of inflammatory factors such as miR-377-3p and TGF-ß in patients with diabetic kidney disease (DKD), and to investigate the regulatory mechanism of transfection of miR-377-3p on the inflammatory response of HK-2 cell induced by high glucose. Methods: According to UACR, patients were divided into normal albuminuria group (Con, n = 29), microalbuminuria group (Micro, n = 31) and macroalbuminuria group (Macro, n = 30), analyzed the correlation and influencing factors between DKD and inflammatory factor. HK-2 cells were randomly divided into four groups: normal control group (NC), high glucose group (HG), miR-377-3p overexpression group (MIN), and miR-377-3p inhibition group (IN). After transfection of miR-377-3p mimics and inhibitors, the contents of TGF-ß, IL-6 and IL-18 were detected by RT-PCR and Western blot. Results: The levels of miR-377-3p, TGF-ß, IL-6 and IL-18 in both Micro group and Macro group were significantly higher than those in Con group (P < 0.05); Pearson correlation analysis showed that miR-377-3p was positively correlated with UACR, TG, TGF-ß, IL-6 and IL-18, and negatively correlated with GFR (P < 0.05). Cell experiment: RT-PCR and Western blot results showed that miR-377-3p, TGF-ß, IL-6 and IL-18 in HG group were significantly higher than those in NC group (P < 0.05). After transfection with miR-377-3p inhibitor, the levels of miR-377-3p, TGF-ß, IL-6 and IL-18 in IN group were significantly decreased compared with HG group and MIN group. Conclusion: miR-377-3p expression was elevated both in serum of DKD patients and in HK-2 cells with high glucose induced injury, overexpression of miR-377-3p exacerbates the damage to HK-2 cells and promotes the progression of DKD. Silencing miR-377-3p can potentially regulate the levels of inflammatory factors in HK-2 cells by targeting downregulation of TGF-ß expression, thereby mitigating the damage to HK-2 cells and delaying the development of diabetic kidney disease.

2.
Immunobiology ; 229(2): 152792, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38401467

RESUMO

OBJECTIVE: The value of novel biomarkers for DKD has received increasing attention, and there is an urgent need for novel biomarkers with sensitivity, specificity and ability to detect kidney damage.miR-377 regulates many basic biological processes, plays a key role in tumor cell proliferation, migration and inflammation, and can also increase the expression of matrix proteins and fibronectin, leading to renal tubulointerstitial inflammation and renal fibrosis. Lipoprotein-associated phospholipase A2, as an inflammatory marker, is involved in the pathological process of microalbuminuria production and renal function decline, and is a predictive factor of microalbuminuria production and renal function decline, and can be used as an indicator to evaluate the progression of DKD.The aim of this study was to investigate the effects of miR-377 and phospholipase A2 on the development of diabetic kidney disease through regulation of inflammatory factors and the mechanism of action. METHODS: 80 diabetic patients were divided into two groups according to urinary albumin-to-creatinine ratio (UACR): diabetic normal proteinuria group (n = 42) and diabetic proteinuria group (n = 38). Forty-three healthy people were selected as the normal control group. The serum levels of TGF-ß, IL-6, and IL-18 were measured by ELISA, miR-377 was detected by qPCR, and the serum levels of phospholipase A2 were detected by electrochemiluminescence. Analyze the correlation of study group indicators, ROC curve was used to evaluate the diagnostic efficacy of miR-377 and phospholipase A2 in diabetic kidney disease. RESULTS: The average levels of serum TGF-ß, IL-6, IL-18, miR-377 and phospholipase A2 in diabetic proteinuria group were significantly higher than those in normal control group and diabetic proteinuria normal group(P < 0.05). miR-377, phospholipase A2 were significantly correlated with inflammatory factors such as glomerular filtration rate and TGF-ß. miR-377 and phospholipase A2 are independent predictors of diabetic kidney disease. The area under the curve of miR-377 and phospholipase A2 in the normal diabetic proteinuria group and the diabetic proteinuria group were 0.731 and 0.744, respectively. CONCLUSION: miR-377 and phospholipase A2 have good diagnostic efficiency for the early diagnosis of diabetic kidney disease. They can be used as early biomarkers.miR-377 and phospholipase A2 were positively correlated with inflammatory factors and involved in the occurrence and development of diabetic kidney disease.


Assuntos
Diabetes Mellitus , Nefropatias Diabéticas , MicroRNAs , Humanos , Nefropatias Diabéticas/diagnóstico , Interleucina-18 , Interleucina-6 , Fosfolipases A2 , Diagnóstico Precoce , Proteinúria , Biomarcadores , Inflamação/diagnóstico , Fator de Crescimento Transformador beta , MicroRNAs/genética
3.
Adv Sci (Weinh) ; 10(34): e2303734, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37814361

RESUMO

Two-dimensional material-based field-effect transistors (2DM-FETs) are playing a revolutionary role in electronic devices. However, before electronic design automation (EDA) for 2DM-FETs can be achieved, it remains necessary to determine how to incorporate contact transports into model. Reported methods compromise between physical intelligibility and model compactness due to the heterojunction nature. To address this, quasi-Fermi-level phase space theory (QFLPS) is generalized to incorporate contact transports using the Landauer formula. It turns out that the Landauer-QFLPS model effectively overcomes the issue of concern. The proposed new formula can describe 2DM-FETs with Schottky or Ohmic contacts with superior accuracy and efficiency over previous methods, especially when describing non-monotonic drain conductance characteristics. A three-bit threshold inverter quantizer (TIQ) circuit is fabricated using ambipolar black phosphorus and it is demonstrated that the model accurately predicts circuit performance. The model could be very effective and valuable in the development of 2DM-FET-based integrated circuits.

4.
Huan Jing Ke Xue ; 44(4): 1841-1851, 2023 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-37040935

RESUMO

PM2.5 and ozone co-pollution, which are harmful to not only human health but also the social economy, has become the pivotal issue in air pollution prevention and synergistic control, especially in Beijing-Tianjin-Hebei and its surrounding areas and "2+26" cities. It is necessary to analyze the correlation between PM2.5 and ozone concentration and explore the mechanism of PM2.5 and ozone co-pollution. In order to study the characteristics of PM2.5 and ozone co-pollution in Beijing-Tianjin-Hebei with its surrounding area, ArcGIS and SPSS software were used to analyze the correlation between air quality data and meteorological data of the "2+26" cities in Beijing-Tianjin-Hebei and its surrounding areas from 2015 to 2021. The results indicated:① PM2.5 pollution constantly decreased from 2015 to 2021, and the pollution was concentrated in the central and southern parts of the region; ozone pollution showed a trend of fluctuation and presented a pattern of "low in the southwest and high in the northeast" spatially. In terms of seasonal variation, PM2.5concentration was mainly in the order of winter>spring ≈ autumn>summer, and O3-8h concentration was in the order of summer>spring>autumn>winter. ② In the research area, days with PM2.5 exceeding the standard continued to decline, whereas days with ozone exceeding the standard fluctuated, and days with co-pollution decreased significantly; there was a strong positive correlation between PM2.5 and ozone concentration in summer, with the highest correlation coefficient of 0.52, and a strong negative correlation in winter. ③ Comparing the meteorological conditions of typical cities during the ozone pollution period with that of the co-pollution period, the co-pollution occurred under the temperature range of 23.7-26.5℃, humidity of 48%-65%, and S-SE wind direction.

5.
Exp Ther Med ; 25(1): 51, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36588813

RESUMO

IL-17 and other cytokines have a number of immunomodulatory effects on thyroid cells. The present study investigated the changes and correlations amongst IL-17, NF-κB, IL-6, IL-10, interferon-γ (IFN-γ), TNF-α, IL-2 and IL-4 in patients with different autoimmune thyroid diseases in order to further clarify the pathogenesis of autoimmune thyroid disease. A total of 82 patients with autoimmune thyroid diseases (41 with Graves' disease and 41 with Hashimoto's thyroiditis) and 53 healthy controls were enrolled. All relevant thyroid hormones were detected by electrochemiluminescence analyzer. The serum levels of IL-17 and other cytokines were detected using flow cytometry, NF-κB was detected by ELISA, reverse transcription-quantitative PCR was used to detect the protein expression of various mRNAs, and the correlations between IL-17 and these factors were analyzed. Significant differences occurred amongst all groups. NF-κB, TNF-α, IL-6, IL-17 and their mRNA levels were significantly higher in the healthy controls compared with those in the patients; whereas IFN-γ and IL-10 levels were significantly lower in the healthy controls compared with those in the patients . Correlation analysis showed that the expression levels of IL-17 and its mRNA were significantly positively correlated with the expression levels of NF-κB, IL-6, thyroid peroxidase antibody, thyroid gland globulin, thyroglobulin antibody, TNF-α and IFN-γ, and were also significantly negatively correlated with IL-10 . These findings suggested that IL-17 was elevated in patients with autoimmune thyroid disease and that IL-17 could activate the NF-κB signaling pathway, stimulate the production and release of inflammatory factors such as TNF-α, IL-6 and IFN-γ and participate in the pathogenesis of autoimmune thyroid injury.

6.
Medicine (Baltimore) ; 101(41): e31102, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36253996

RESUMO

BACKGROUND: To study the changes and effects of angiotensin-converting enzyme 2 (ACE2)/angiotensin 1-7 (Ang1-7) and ACE/AngII in people with different glucose metabolisms and to explore the possible mechanisms underlying the severity of COVID-19 infection in diabetic patients. METHODS: A total of 88 patients with type 2 diabetes, 72 patients with prediabetes (impaired fasting glucose, 30 patients; impaired glucose regulation, 42 patients), and 50 controls were selected. Changes and correlations of ACE2, Ang1-7 and other indicators were detected among the three groups. Patients were divided into four groups according to the course of diabetes: <1 year, 1-5 years, 5-10 years, and >10 years. ACE2 and Ang1-7 levels were compared and analyzed. RESULTS: ACE2 and Ang1-7 increased with the severity of diabetes (P0 < .05 or P < .01). The levels of ACE2 and Ang1-7 in the longer course group were lower than those in the shorter course group, whereas the levels of ACE, Ang II, and interleukin-6 (IL-6) gradually increased (P < .05). Pearson correlation analysis showed that ACE2 was positively correlated with IL-6, FBG, and 2hPBG levels in the prediabetes group. In the diabetic group, ACE2 was positively correlated with Ang1-7 and negatively correlated with ACE, AngII, IL-6, and C-reactive protein levels. Multiple linear regression analysis showed that IL-6 and ACE were the main factors influencing ACE2 in the diabetic group. CONCLUSION SUBSECTIONS: ACE2/Ang1-7 and ACE/AngII systems are activated, and inflammatory cytokine release increases in prediabetes. With the prolongation of the disease course, the effect of ACE2/Ang1-7 decreased gradually, while the effect of ACE/AngII increased significantly. Dysfunctions of ACE2/Ang1-7 may be one of the important mechanisms underlying the severity of COVID-19 infection in patients with diabetes.


Assuntos
Enzima de Conversão de Angiotensina 2 , COVID-19 , Diabetes Mellitus Tipo 2 , Estado Pré-Diabético , Humanos , Angiotensina I/metabolismo , Angiotensina II , Enzima de Conversão de Angiotensina 2/metabolismo , Proteína C-Reativa , Glucose , Interleucina-6 , Fragmentos de Peptídeos/metabolismo
7.
Nature ; 603(7900): 259-264, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35264756

RESUMO

Ultra-scaled transistors are of interest in the development of next-generation electronic devices1-3. Although atomically thin molybdenum disulfide (MoS2) transistors have been reported4, the fabrication of devices with gate lengths below 1 nm has been challenging5. Here we demonstrate side-wall MoS2 transistors with an atomically thin channel and a physical gate length of sub-1 nm using the edge of a graphene layer as the gate electrode. The approach uses large-area graphene and MoS2 films grown by chemical vapour deposition for the fabrication of side-wall transistors on a 2-inch wafer. These devices have On/Off ratios up to 1.02 × 105 and subthreshold swing values down to 117 mV dec-1. Simulation results indicate that the MoS2 side-wall effective channel length approaches 0.34 nm in the On state and 4.54 nm in the Off state. This work can promote Moore's law of the scaling down of transistors for next-generation electronics.

8.
Oncol Rep ; 45(2): 469-480, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33416160

RESUMO

Long non­coding RNA (lncRNA) forkhead box P4 antisense RNA 1 (FOXP4­AS1) has been determined to function as an oncogene in various types of cancer. However, the biological function and the underlying mechanisms of FOXP4­AS1 in mantle cell lymphoma (MCL) remain to be uncovered. The expression and the associated clinicopathological characteristics and prognostic significance of FOXP4­AS1 were explored in MCL clinical samples. The effects of FOXP4­AS1 on MCL cellular behaviors, including proliferation, migration and invasion were analyzed using CCK­8, crystal violet and Transwell assays. The downstream molecules of FOXP4­AS1 were explored using bioinformatics analysis and dual luciferase assay. Our results showed that FOXP4­AS1 expression was upregulated in MCL patients, and that the high expression of FOXP4­AS1 was correlated with the unfavorable prognosis of patients. Functionally, while FOXP4­AS1 downregulation inhibited proliferation, migration and invasion of MCL cells, FOXP4­AS1 overexpression had promotive effects on these cellular processes. Mechanistically, FOXP4­AS1 was found to act as a competing endogenous (ce)RNA for miR­423­5p to regulate the expression of nucleus accumbens­associated 1 (NACC1). The negative regulation of FOXP4­AS1 on miR­423­5p compared to that of miR­423­5p on NACC1 was determined at the mRNA or protein levels in MCL cells. Moreover, an inverse expression correlation between FOXP4­AS1 and miR­423­5p, and that between miR­423­5p and NACC1 was confirmed in MCL clinical samples. In addition, rescue assay showed that miR­423­5p upregulation or NACC1 knockdown abolished the promoting effects of FOXP4­AS1 on MCL cell proliferation, migration and invasion. In conclusion, FOXP4­AS1 promotes MCL progression through the upregulation of NACC1 expression by inhibiting miR­423­5p. FOXP4­AS1 may serve as a novel therapeutic target for patients with MCL.


Assuntos
Linfoma de Célula do Manto/genética , MicroRNAs/metabolismo , Proteínas de Neoplasias/genética , Recidiva Local de Neoplasia/epidemiologia , RNA Longo não Codificante/metabolismo , Proteínas Repressoras/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Biologia Computacional , Progressão da Doença , Intervalo Livre de Doença , Feminino , Seguimentos , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Linfoma de Célula do Manto/mortalidade , Linfoma de Célula do Manto/patologia , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , Recidiva Local de Neoplasia/genética , Prognóstico , RNA Longo não Codificante/genética , Regulação para Cima
9.
Front Pharmacol ; 11: 1316, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32982736

RESUMO

Postmenopausal osteoporosis (PMOP) is a common metabolic bone disease in postmenopausal women in the Worldwide, and seriously affects the quality of life of middle-aged and elderly women. Therefore, there is an urgent need to discover a highly effective drug for PMOP treatment. In this study, ultra-high performance liquid tandem quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was used to analyze the urine metabolic profiling and potential biomarkers, the relevant metabolic network of PMOP rats, and further to evaluate the intervention effect of Eleutheroside E (EE) against PMOP. Using multivariate statistical analysis combined with UPLC-Q/TOF-MS, a total of 27 biomarkers were identified, which related with 16 metabolic pathways, mainly involving steroidogenesis, beta oxidation of very long chain fatty acids, glutathione metabolism, carnitine synthesis, estrone metabolism, oxidation of branched chain fatty acids, etc. After treatment of EE, these biomarkers were markedly regulated, mainly involving steroid hormone biosynthesis, arachidonic acid metabolism, primary bile acid biosynthesis, indicating that EE had the therapeutic effect on PMOP. This study identified the potential urine metabolic markers and related metabolic pathways of the PMOP, explained the metabolic effect and pharmacological mechanisms of EE against PMOP, and provided a basis for the pharmacological study of EE.

10.
Huan Jing Ke Xue ; 41(3): 1045-1055, 2020 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608604

RESUMO

To investigate the variations and sources of n-alkanes and sugars in Taian City during summer, PM2.5 samples were collected from July 22 to August 19, 2016. The identified n-alkane and sugar sources were investigated using a principal component analysis (PCA) multiple linear regression (MLR) model and a backward trajectory model. The results showed that the mass concentrations of PM2.5 during summer were (37.2±11.5) µg·m-3. The mass concentrations of n-alkanes were (83.3±34.7) ng·m-3, the carbon preference index (CPI) was 1.83, and the relative contribution of wax n-alkanes was 34.7%-69.4%, suggesting that contributions from terrestrial plants were more significant in Taian City. The results showed that the mass concentrations of sugars in Taian City during summer were (73.4±46.6) ng·m-3. Levoglucan, galactosan, and mannosan were the main saccharides, accounting for 64.0%, 7.1%, and 6.3% of the total concentrations of sugars, respectively, indicating that biomass burning is much more significant in Taian City. The results of the PCA-MLR model suggested that n-alkanes and sugars in Taian City during summer were mostly from terrestrial plants, coal burning and biomass burning. The backward trajectory model showed that the pollution mostly came from the native sources of Shandong province and the inland cities in the south.

11.
Huan Jing Ke Xue ; 40(10): 4319-4329, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854798

RESUMO

To investigate the diurnal variations and sources of water-soluble compounds in Liaocheng City, PM2.5 samples were collected between January and February 2017. The PM2.5 samples were analyzed for the compositions, concentrations, and sources of water-soluble inorganic ions, oxalic acid, and levoglucosan. The sources of these chemical compound were investigated using principal component analysis (PCA) and multiple linear regression (MLR) modeling. The results showed that the mass concentrations of PM2.5during the nighttime were higher than those during the daytime, and the average concentrations exceeded the National Ambient Air Quality Standard (GB 3095-2012) by more than 1.8 times. Moreover, atmospheric pollution was worse during the day than during the night. SNA (SO42-, NO3-, and NH4+) were the dominant species among the inorganic ions, the relative abundance of which with respect to the total concentrations of inorganic ions was 73.4% and 77.1% during the daytime and nighttime, respectively. The ratios of anion to cation equivalents (AE/CE) were less than one, suggesting that the PM2.5 was slightly alkaline, and the degree of acidity at night was stronger than during the day. The results of the correlation analyses suggested that aqueous-phase oxidation was the major formation pathway of oxalic acid, which is driven by acid-catalyzed oxidation. The oxalic acid was mainly influenced by biomass burning during the winter in Liaocheng City. The results of the PCA-MLR model suggested that water-soluble compounds in Liaocheng City were mostly from vehicular emissions and secondary oxidation, biomass burning, while the impacts of mineral dust and coal burning were relatively minor.

12.
Huan Jing Ke Xue ; 40(9): 3875-3885, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854849

RESUMO

To investigate the mass concentrations, sources, and health effects of polycyclic aromatic hydrocarbons (PAHs) in ambient particulate matter (PM) in Liaocheng City during winter, 14 types of PAHs in PM2.5 were determined from January to February of 2017. The sources of the PAHs were analyzed by using diagnostics ratios and the principal component analysis (PCA)-multiple linear regression (MLR) model,and the health risk of PAHs was assessed by BaP equivalent concentrations (BaPeq) and incremental lifetime cancer risk (ILCR). The results showed that the mass concentrations of PAHs in PM2.5 during winter were (64.89±48.23) ng·m-3, Fla, Pyr, and Chry were predominant species, accounting for 15.5%, 12.8%, and 12.7% of the total concentrations of PAHs, respectively. Moreover, the ring distribution of the PAHs was dominated by four-ring PAHs. The pollution during the pre-Spring Festival and firework Ⅱwere the most severe during the sampling period. The results of the PCA-MLR model suggested that PAHs originated mostly from coal burning, biomass burning, and vehicle emissions. The toxicity exposure index (TEQ) in Liaocheng City during winter was (6.37±4.92) ng·m-3. The results of the risk model revealed that the ILCR of adults was higher than that of children, and both groups of ILCR for winter were in the range of the risk threshold. This suggests that a potential risk in terms of inhalation PAH exposure for residents in Liaocheng City.


Assuntos
Poluentes Atmosféricos , Saúde Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Medição de Risco , Adulto , Criança , China , Cidades , Monitoramento Ambiental , Humanos , Material Particulado , Estações do Ano
13.
Huan Jing Ke Xue ; 40(2): 548-557, 2019 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-30628316

RESUMO

To investigate molecular composition, mass concentrations, and sources of n-alkanes and sugars which are adsorbed in ambient particulate matters in Liaocheng City during winter, PM2.5 samples were collected from January 17 to February 15, 2017 at Liaocheng University. 19 kinds (C18-C36) of n-alkanes and 10 kinds of sugars were determined using GC-MS. The identification of n-alkane and sugar sources were investigated using principal component analysis (PCA). The results showed that the mass concentrations of total n-alkanes in PM2.5 during the winter were (456.9±252.5) ng·m-3. During the haze period, the concentrations of n-alkanes were two times higher than those on clear days. Additionally, the concentrations of n-alkanes during fireworks event I and fireworks event Ⅱ were 0.9 times and 1.2 times higher than those on clear days. During the sampling period, the Carbon preference index (CPI) was 1.2±0.1, and the contribution from plant wax concentrations for n-alkanes (% Wax Cn) was between 3.1%~36.0%, indicating that fossil fuels were the major source of n-alkanes in Liaocheng City during the winter. The mass concentrations of saccharides in PM2.5 during the winter were (415.5±213.8) ng·m-3. Levoglucosan was the most abundant species, followed by galactosan and mannosan, which accounted for more than 91.6% of total saccharides, indicating that biomass burning was much more significant in Liaocheng City. PCA further suggested that n-alkane and saccharide compounds in atmospheric aerosol during the winter in Liaocheng City were primarily derived from fossil fuel and biomass burning.

14.
Opt Lett ; 43(22): 5599-5602, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30439905

RESUMO

We demonstrate a 266 nm ultraviolet (UV) picosecond laser by fourth-harmonic generation of a Nd:YAG laser with a 5.4 mm thick NaSr3Be3B3O9F4 (NSBBF) crystal. A maximum output power exceeding 1 W at 266 nm was obtained (the highest output power being 1.6 W), corresponding to a conversion efficiency of 10.3%. The stability measurements on the NSBBF crystal with a fluctuation of 3.34% at 200 mW within 1 h indicate that it is a promising UV nonlinear optical material for practical applications. In addition, for the first time, to the best of our knowledge, we measured the effective nonlinear coefficient of NSBBF crystal at 266 nm and compared it with that of ß-BaB2O4 crystal.

15.
Huan Jing Ke Xue ; 39(9): 4014-4025, 2018 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-30188041

RESUMO

To investigate seasonal variations in the chemical compositions of aerosols in Ji'nan City, PM2.5 samples were collected during summer and winter in 2015. The sampling period lasted one month during each season. PM2.5 samples were analyzed for the composition, concentration, and sources of water-soluble inorganic ions, organic carbon (OC), elemental carbon (EC), and water-soluble organic carbon (WSOC). Results showed that mass concentrations of PM2.5 in winter were about twice those in summer, and concentration levels varied between fine and excellent. The concentrations of total water-soluble inorganic ions were also higher in winter than in summer, with SO42-, NO3-, and NH4+ being the dominant species and well correlated with each other. NH4+ in PM2.5 mostly existed in the form of (NH4)2SO4 and NH4NO3 in both summer and winter. There was strong secondary oxidation of SO2 and NO2. The sulfate oxidizing rate (SOR) was higher in summer than in winter, while the nitrate oxidizing rate (NOR) showed the opposite trend. The ratio of anions to cations in both summer and winter were less than one, suggesting that PM2.5 were slightly alkaline. The ISORROPIA-Ⅱ mode showed that acidity in winter was stronger than in summer. Concentations of OC and EC were both higher in winter than in summer. The ratios of OC to EC and WSOC to OC and estimated concentrations of secondary organic carbon (SOC) showed that secondary pollution was more serious in winter than in summer. Principal component analysis(PCA)indicated that the major sources contributing to inorganic ions were secondary oxidation and biomass burning in summer, and coal combustion and secondary pollutants formed by chemical oxidation of precursors emitted from coal combustion in winter.

16.
Huan Jing Ke Xue ; 39(11): 4876-4884, 2018 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-30628208

RESUMO

To identify the diurnal variation and formation mechanism of dicarboxylic acids and related compounds in PM2.5 from Heze City, PM2.5 samples were collected in the winter (December) of 2017, which were subsequently analyzed for dicarboxylic acids, ketocarboxylic acids, α-dicarbonyls, and levoglucosan (Levo). The results showed that the total concentrations of dicarboxylic and ketocarboxylic acids were higher during daytime than those during nighttime. In contrast to the diurnal variation of dicarboxylic and ketocarboxylic acids, the total concentrations of α-dicarbonyls exhibited higher concentrations in nighttime than in daytime. Because α-dicarbonyls are the major precursors of dicarboxylic acids, the opposing patterns suggest that the photochemical oxidation in daytime is stronger than that in nighttime. Oxalic acid (C2) is the dominant species during both day-and nighttime, followed by phahalic acid (Ph), succinic acid (C4), and malonic acid (C3), which is consistent with that in other urban regions. The mass ratios of C3/C4 (R2>0.7) correlated strongly with temperature, indicating that organic compounds in the atmosphere of Heze City are mainly derived from the photochemical oxidation of local emissions rather than long-range transport in winter. C2 correlated with in-situ pH and SO42-, suggesting that aqueous-phase oxidation was the major formation pathway of C2, which is driven by acid-catalyzed oxidation. Since the major SOA (C2, glyoxal, and methyglyoxal, secondary organic aerosol) correlated with Levo and the average mass rations of K+/organic carbon was 0.06 (ranging from 0.03 to 0.13), it can be concluded that the dicarboxylic acids and related SOA and K+ in Heze City were significantly influenced by biomass burning in winter.

17.
Opt Express ; 25(22): 26500-26507, 2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29092139

RESUMO

266 nm laser output in NaSr3Be3B3O9F4 crystal by the fourth harmonic generation process with a picosecond mode-locked Nd-based YAG laser has been done for the first time. When the input pumping energy was 870 µJ at 532 nm, a 280 µJ 266 nm UV laser was obtained and the corresponding conversion efficiency was 35.9%. Further investigations identified that NaSr3Be3B3O9F4 has a large acceptance angle width of 0.47 (mrad • cm), a small walk-off angle of 35.43 mrad and a large deff as 0.62 pm/V for the fourth harmonic generation. These results indicate that NSBBF is applicable for high-power 266 nm laser generation.

18.
Huan Jing Ke Xue ; 38(2): 445-452, 2017 Feb 08.
Artigo em Chinês | MEDLINE | ID: mdl-29964498

RESUMO

To identify the compositions and sources of dicarboxylic acids and related SOA in Mt. Taishan, PM2.5 samples were collected from July to August, 2004, and analyzed for dicarboxylic acids and related compounds, the tracers of biogenic secondary organic aerosol (SOA) (Isopene, α-/ß-Pinene and ß-caryophyllene SOA tracers), water-soluble organic carbon (WSOC) and inorganic ions. The results showed that total dicarboxylic acids were (376±189) ng·m-3, and C2 was the most abundant dicarboxylic acid, followed by C3, C4 and C9. The concentrations of diacids were more abundant than those in marine regions, but lower than those in urban and other mountainous areas, indicating that the atmosphere in Mt. Taishan was less influenced by anthropogenic pollution. C2/C4, C3/C4 and F/M ratios indicated that diacids were mostly produced by more intensive photochemical oxidation. The relative abundance of C9 to the total diacids, C9/C6 and C9/Ph ratios were higher than those in urban, marine and mountainous regions, further suggesting that SOA in Mt. Taishan atmosphere were mostly derived from biogenic sources rather than anthropogenic sources. Compared to the budgets of model and correlation analysis, it suggested that diacids and related SOA in Mt. Taishan were mostly derived from photochemical oxidation of local biogenic sources.

19.
Huan Jing Ke Xue ; 38(7): 2688-2697, 2017 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-29964607

RESUMO

To identify the seasonal variation of dicarboxylic acids and related compounds in PM10 from Mt. Huangshan. PM10samples were collected during the summer and winter of 2015, which were then analyzed for dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls. The results showed that oxalic acid(HOOC-COOH, C2) was the dominant species in the summer and winter months, followed by malonic acid(HOOC-CH2-COOH, C3), and succinic acid[HOOC-(CH2)2-COOH, C4], being consistent with that in other high-altitude regions. Most of the diacids were more abundant in the summer months than in the winter months, while adipic acid(C6) and phahalic acid(Ph) were twice lower in the summer months, suggesting significant impact of anthropogenic pollution on the wintertime alpine atmosphere. Moreover, as major precursors of C2, glyoxal(Gly) and methylglyoxal(mGly) were also lower in the summer months than in the winter months, which were opposite to those of the diacids, indicating that the mountain troposphere was more oxidative in the summer months than in the winter months. Principal component analysis(PCA) further revealed that the wintertime SOA in the Mt. Huangshan troposphere mostly originated from the anthropogenic pollutants from long-distance transport. Conversely, the summertime SOA mostly originated from the further oxidation of the mountainous biogenic sources. The AIM(Aerosol Inorganic Model) calculation results showed that the aqueous-phase C2 production was the primary mechanism of C2 formation in ambient aerosol and was driven by acid-catalyzed oxidation in summer.

20.
Langmuir ; 29(22): 6537-45, 2013 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-23651167

RESUMO

A hybrid was at first synthesized by a postfunctionalization of an aminomethane trisalkoxo-functionalized Anderson-type polyoxometalate (POM) encapsulated by three tetrabutylammonium ions using a 3,5-bis(tetradecyloxy)benzoic acid by amidation. Then the three TBA(+) counter cations were programmatically replaced by protons (H(+)) following a molecule-to-amphiphile conversion. In this way one hybrid and three POM-containing hybrid amphiphiles (PCHAs) were acquired by adjusting the number (n) of TBA(+) ions and number (3 - n) of H(+) ions (n = 3, 2, 1, and 0). These compounds can be spread onto a water surface to form a Langmuir monolayer film at the air-water interface. Surface pressure-molecular area measurements exhibit the TBA(+) (H(+)) number playing an important role in the forming ability and stability of Langmuir monolayer films. Also, the Langmuir-Blodgett (LB) technique has been used to transfer the monolayer film onto solid supports to fabricate solid multilayer films. It was found that the PCHA with three H(+) ions had the best Langmuir film-forming ability and thus formed stable LB films with a two-dimensional ordered structure. Our findings are instructive in fabricating and using solid films of the amphiphiles with POM headgroups.


Assuntos
Prótons , Compostos de Amônio Quaternário/química , Tensoativos/química , Compostos de Tungstênio/química , Ar , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Propriedades de Superfície , Água
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