Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 380
Filtrar
1.
BMC Complement Med Ther ; 20(1): 16, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-32020888

RESUMO

BACKGROUND: Quantitation analysis and chromatographic fingerprint of multi-components are frequently used to evaluate quality of herbal medicines but fail to reveal activity of the components. It is necessary to develop a rational approach of chromatography coupled with activity detection for quality assessment of herbal medicines. METHODS: An on-line HPLC-ultraviolet detection-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radical scavenging (HPLC-UV-ABTS) method was developed to obtain the chromatographic fingerprints and ABTS+• inhibition profiles (active fingerprints) of Rehmanniae Radix (Dihuang) and Rehmannia Radix Praeparata (Shu Dihuang). Eighteen compounds showing ABTS+• inhibition activity were identified by HPLC-fourier-transform mass spectrometry (HPLC-FTMS). Verbascoside was used as a positive control to evaluate the total activities of the samples and the contribution rate of each compound. The similarities of the chromatographic and active fingerprints were estimated by the vectorial angle cosine method. RESULTS: The results showed that the HPLC-UV-ABTS method could efficiently detect antioxidant activity of the herbal medicine samples. The antioxidants were different between the two herbs and several new antioxidants were identified in Shu Dihuang. A function equation was generated in terms of the negative peak area (x) and the concentrations of verbascoside (y, µg/mL), y = 2E-07 × 4 - 8E-05 × 3 + 0.0079 × 2 + 0.5755x + 1.4754, R2 = 1. Iridoid glycosides were identified as main antioxidants and showed their higher contributions to the total activity of the samples. The total contributions of the three main active components in the Dihuang and Shu Dihuang samples to the total activity, such as echinacoside, verbascoside and an unknown compound, were 39.2-58.1% and 55.9-69.4%, respectively. The potencies of the main active components in the Shu Dihuang samples were two to ten times those in the Dihuang samples. Similarity values for S12 in the chromatographic fingerprints and S03, S12 and P03 in the active fingerprints were less than 0.9. The three batches of samples might show their different quality with the other samples. CONCLUSIONS: The results suggested that the combination of "quantity-effect" research strategy and the HPLC-UV-ABTS analysis method could comprehensively evaluate the active components and quality of Dihuang and Shu Dhuang.

2.
J Hazard Mater ; 390: 122144, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-32006845

RESUMO

Many studies have examined changes in soil microbial community structure and composition by carbon nanomaterials (CNMs). Few, however, have investigated their impact on microbial community functions. This study explored how fullerene (C60) and multi-walled carbon nanotubes (M50) altered functionality of an agricultural soil microbial community (Archaea, Bacteria and Eukarya), using microcosm experiments combined with GeoChip microarray. M50 had a stronger effect than C60 on alpha diversity of microbial functional genes; both CNMs increased beta diversity, resulting in functional profiles distinct from the control. M50 exerted a broader, severer impact on microbially mediated nutrient cycles. Together, these two CNMs affected CO2 fixation pathways, microbial degradation of diverse carbohydrates, secondary plant metabolites, lipids and phospholipids, proteins, as well as methanogenesis and methane oxidation. They also suppressed nitrogen fixation, nitrification, dissimilatory nitrogen reduction, eukaryotic assimilatory nitrogen reduction, and anaerobic ammonium oxidation (anammox). Phosphorus and sulfur cycles were less vulnerable; only phytic acid hydrolysis and sulfite reduction were inhibited by M50 but not C60. Network analysis suggested decoupling of nutrient cycles by CNMs, manifesting closer and more hierarchical gene networks. This work reinforces profound impact of CNMs on soil microbial community functions and ecosystem services, laying a path for future investigation in this direction.

3.
Aging (Albany NY) ; 122020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32023223

RESUMO

Hemorrhagic transformation (HT) is a common complication in patients with acute ischemic stroke. We investigated whether the monocyte to high-density lipoprotein ratio (MHR) is related to HT. Consecutive patients with ischemic stroke within 24 h of symptom onset were included in this study. HT was diagnosed by follow-up brain imaging after admission, and was classified as asymptomatic or symptomatic according to whether patients showed any neurologic worsening. Logistic regression was performed to estimate the association between MHR and HT. Of the 974 enrolled patients, 148 (15.2%) developed HT, and 24 (2.5%) patients experienced symptomatic HT. Compared to the highest MHR tertile (> 0.37), the lowest MHR tertile (< 0.22) was associated with 1.81-fold increase (95% CI 1.08-3.01, P = 0.024) in the odds of HT and 3.82-fold increase (95% CI 1.04-14.00, P = 0.043) in the odds of symptomatic HT after adjustment for possible confounders. Using a multivariate logistic regression model with restricted cubic spline, we found that elevated MHR was associated with a decreased risk of HT and symptomatic HT. In summary, lower MHR was independently associated with increased risk of HT and symptomatic HT in patients with ischemic stroke.

4.
Sci Total Environ ; 715: 136903, 2020 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-32032987

RESUMO

N2O and NO emissions from a winter wheat-summer maize rotation field in the North China Plain were comparably investigated under three different treatments: 1) flood irrigation (A-Flood treatment) plus fertilization of NH4Cl, 2) drip fertigation (A-Drip treatment) plus fertilization of NH4Cl and 3) drip fertigation (AN-Drip treatment) plus fertilization of a mixture of Ca(NO3)2 and NH4Cl. The annual N2O cumulative emissions from the A-Drip treatment and the A-Flood treatment were almost identical, whereas it from the AN-Drip treatment was significantly lower (33%) than that from the A-Flood treatment. Compared with the A-Flood treatment, the annual NO cumulative emission from the A-Drip treatment was significantly increased by 140% but it from the AN-Drip treatment was only slightly increased by 14%. Compared with drip fertigation with NH4Cl, drip fertigation with the mixture of Ca(NO3)2 and NH4Cl significantly reduced the cumulative emissions of N2O (31%) and NO (52%) from the nitrification dominated fields by decreasing the supplement of NH4+ substrate. Among the three fertilization treatments, the yields of the maize from the A-Drip and AN-Drip treatments were significantly increased, while the yields of the wheat were almost the same. Considering the benefit of increasing yields and reducing N fertilizer and water input, the application of nitrate-based fertilizer instead of partial ammonium-based fertilizer through drip fertigation could be a promising method for keeping agronomic productivity and environmental sustainability.

5.
BMC Neurol ; 20(1): 47, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32033596

RESUMO

BACKGROUND: It is unclear whether non-high-density lipoprotein cholesterol (Non-HDL-C) is associated with haemorrhagic transformation (HT) after acute ischaemic stroke (AIS). We aimed to explore the association between Non-HDL-C and HT, as well as compare the predictive values of Non-HDL-C and low-density lipoprotein cholesterol (LDL-C) for HT. METHODS: We consecutively enrolled AIS patients within 7 days of stroke onset. Participants were divided into four categories according to quartiles of Non-HDL-C. HT was assessed by follow-up brain imaging. We assessed the association between Non-HDL-C, LDL-C and HT in multivariate logistic regression analysis. RESULTS: A total of 2043 patients were included, among whom 232 were identified as HT. Compared with the highest quartiles, the first, second and third quartiles of Non-HDL-C were associated with increased risk of HT (adjusted odds ratios [ORs] 1.74 [95% confidence interval [CI] 1.09-2.78], 2.01[95% CI 1.26-3.20], and 1.76 [95% CI 1.10-2.83], respectively, P for trend = 0.024). Similar results were found for LDL-C. There was significant interaction between Non-HDL-C and age (P for interaction = 0.021). The addition of Non-HDL-C and LDL-C to conventional factors significantly improved predictive values [Non-HDL-C, net reclassification index (NRI) 0.24, 95%CI 0.17-0.31, P < 0.001; LDL-C, NRI 0.15, 95%CI 0.08-0.22, P = 0.03]. CONCLUSIONS: Low Non-HDL-C was associated with increased risks of HT. In addition, Non-HDL-C has similar effects as LDL-C for predicting HT.

6.
Biol Trace Elem Res ; 2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32016827

RESUMO

Cadmium (Cd) is a ubiquitous toxic heavy metal in the natural environment that can cause multiple organ damage to the bodies of animals and humans. Selenium yeast (SeY) is a kind of organic selenium (Se) that has a very strong function against Cd-induced injury to tissues or organs. The aim of the current study was to investigate the roles of inflammatory factors and heat shock proteins (HSPs) in inflammatory injury triggered by Cd and to analyze the protective effects of SeY on Cd-induced damnification in the livers of chickens. Two hundred 120-day-old layers were randomly divided into four groups and raised on a conventional diet, or with Se (0.5 mg/kg SeY), Cd (150 mg/kg CdCl2), or Se + Cd (0.5 mg/kg SeY and 150 mg/kg CdCl2) in their basic diets for 120 days. Then, the liver histopathology, production of nitric oxide (NO), activity of inducible NO synthase (iNOS), and mRNA and protein expression levels of inflammatory factors (iNOS, NF-κB, TNF-α, and PTGE) and heat shock proteins (HSPs 27, 40, 60, 70, and 90) were examined. The results showed that exposure to Cd obviously increased Cd accumulation, NO production, iNOS activity, inflammatory factor, and HSP mRNA and protein expression levels and further caused an inflammatory response. Supplementation with SeY had an antagonistic effect on Cd-induced inflammatory injury in chicken livers. Thus, the present study suggests that SeY can be taken as a potential therapeutic for Cd-induced liver inflammatory injury in chickens.

7.
J Cell Physiol ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32003008

RESUMO

Acute lung injury (ALI), characterized by increased excessive pulmonary inflammation, is a pervasive inflammatory disease with clinically high incidence. MicroRNA (miRNAs) have been associated with the progression of multiple diseases and are regarded as novel regulators of inflammation. However, it remains largely unknown whether the miRNAs-mediated regulatory mechanism has an effect on lipopolysaccharide (LPS)-induced inflammation in ALI. We discovered that miR-182 distinctly lessened expression in the lung tissue of mice with ALI and macrophages stimulated by LPS. We also found that overexpression of miR-182 significantly cut down the secretion of inflammatory cytokines, while this change was reversed by inhibition of miR-182. In addition, miR-182 suppressed the activation of NF-κB by targeting TLR4 expression. And it was confirmed that miR-182 directly regulated TLR4 expression at the posttranscriptional level by binding to the 3'-UTR of TLR4. Together, these data suggested that inhibition of TLR4 expression assuaged LPS-stimulated inflammation through negative feedback regulation of miR-182.

8.
J Photochem Photobiol B ; 202: 111716, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31821944

RESUMO

Though anesthetic drug delivery system and drug vehicles is generally applied for pain relief, there are have many difficulties and issues due to its short duration carrier and low biocompatibility, effectiveness at the conditions of inflammation at acidic pH. To resolve this issue, we have designed and developed the dual (pH and temperature) responsive bio-nanomaterial to improve the efficiency anesthetic drug delivery system. Chitosan is a unique class of biomaterials that is widely used in medical devices. The surface engineering of ZnFe2O4 nanoparticles was performed by coating with chitosan using simple precipitation method. Then, multi-active anesthetic drug (Lidocaine) was loaded into nano-ferrite to form a drug delivery vehicle. The prepared drug-vesicle was characterized by using XRD, FTIR, SEM, XPS and TGA analysis. XRD analysis proved the face center cubic structure of zinc nanoferrite. The sustained delivery of Lidocaine (LDC) from CS coated nanoferrite (CS/ZnFe2O4) was stimulated by pH and temperature responsive characteristics of vesicles. The in vitro cytotoxicity of the CS/ZnFe2O4 particles towards fibroblast cells was analyzed by using MTT assay. The drug loaded CS/ZnFe2O4 particles exhibit high biocompatibility and sustained drug release in the physiological pH environment (4.8, 5.5 and 7.4) and temperature responsive (25 and 37 °C) of normal tissues and also drug loading efficiency was measured.


Assuntos
Anestésicos/química , Quitosana/química , Portadores de Fármacos/química , Nanoestruturas/química , Anestésicos/metabolismo , Anestésicos/uso terapêutico , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Liberação Controlada de Fármacos , Humanos , Concentração de Íons de Hidrogênio , Lidocaína/química , Lidocaína/metabolismo , Magnetismo , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/toxicidade , Nanoestruturas/toxicidade , Dor/tratamento farmacológico , Ratos , Temperatura Ambiente
9.
Phys Chem Chem Phys ; 22(2): 430-436, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31675033

RESUMO

Hydrogen energy is a high-efficiency and clean energy, but the problem of storage still prevents its extensive use. Large-surface-area, two-dimensional (2D) layered materials have an advantage in hydrogen storage applications. Monolayer MoS2 is a typical 2D material that has been widely studied recently. And the 1T' phase of MoS2 is a focus especially for studies concerning hydrogen. Here, first-principles calculations are carried out to investigate the adsorption behaviors of hydrogen molecules on 1T' MoS2. Comparing with other MoS2-based materials, such as doped or decorated 2H-MoS2, 1T' MoS2 has even better performance in hydrogen adsorption, and its preparation is easier. In multiple hydrogen molecule adsorption, the material shows good stability and appropriate adsorption energy while adsorbing hydrogen molecules. With the researches in this paper, the connection between the adsorption energy and hydrogen mass fraction was set up. This can provide a reference for further studies on hydrogen storage applications.

10.
J Mol Neurosci ; 70(1): 94-101, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31486972

RESUMO

Uric acid (UA) is an antioxidant with neuroprotective effects in experimental stroke models. Whether serum UA plays a role in hemorrhagic transformation (HT) remains unclear. We aimed to explore the association between serum UA and HT in patients with acute ischemic stroke (AIS). AIS patients within 7 days after stroke onset were consecutively enrolled between January 2016 and October 2017. Patients were categorized into three groups according to serum UA tertiles by sex. HT was detected by follow-up CT or MRI within 7 days after admission. The multivariate logistic analysis was performed to assess the association of serum UA with HT. We included 1230 patients (mean age 64.1 years, 63.5% males) and 133 (10.8%) patients experienced HT. After adjusting confounders, patients in the second and third UA tertiles showed a significant decrease in HT compared with those in the lowest tertile (OR 0.432, 95% CI 0.266-0.702; OR 0.033, 95% CI 0.013-0.086, respectively). Similar results were observed for sex-based subgroups. Males with higher UA had lower risk of HT compared with the lowest UA tertile (OR 0.332, 95% CI 0.170-0.651; OR 0.008, 95% CI 0.001-0.070, respectively). In females, the highest UA tertile was inversely associated with HT (OR 0.148, 95% CI 0.058-0.376). Multiple-adjusted spline regression analyses further confirmed the dose-response relationship between UA levels and HT. Higher serum UA is independently associated with lower HT following stroke. More studies are needed to elucidate the potential neuroprotective mechanism of serum UA and its link to HT.

11.
J Environ Manage ; 253: 109751, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31675594

RESUMO

Using 2025 as the target year, we quantitatively assessed the reduction potentials of emissions of primary pollutants (including CO, HC, NOx, PM2.5 and PM10) under different vehicle control policies and the impacts of vehicle emission control policies in the BTH region on the regional PM2.5 concentration in winter and the surface ozone (O3) concentration in summer. Comparing the different scenarios, we found that (1) vehicle control policies will bring significant reductions in the emissions of primary pollutants. Among the individual policies, upgrading new vehicle emission standards and fuel quality in Beijing, Tianjin, and Hebei will be the most effective policy, with emission reductions of primary pollutants of 26.3%-54.7%, 38.0%-70.3% and 46.0%-81.6% in 2025, respectively; (2) for PM2.5 in winter, the Combined Scenario (CS) will lead to a reduction of 0.5-3.9 µg m-3 (3.5%-11.6%) for the monthly average PM2.5 concentrations in most areas. The monthly nitrate and ammonium concentrations would reduce by 5.8% and 5.3%, respectively, in the whole BTH region, indicating that vehicle emission control policies may play an important role in the reduction of PM2.5 concentrations in winter, especially for nitrate aerosols; and (3) for O3 concentrations in summer, vehicle emission control policies will lead to significant decreases. Under the CS scenario, the maximum reduction of monthly average O3 concentrations in the summer is approximately 3.6 ppb (5.9%). Most areas in the BTH region have a decrease of 15 ppb (7.5%) in peak values compared to the base scenario. However, in some VOC-sensitive areas in the BTH region, such as the southern urban areas, significant reductions in NOx may lead to increases in ozone concentrations. Our results highlight that season- and location-specific vehicle emission control measures are needed to alleviate ambient PM2.5 and O3 pollution effectively in this region due to the complex meteorological conditions and atmospheric chemical reactions.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Pequim , China , Monitoramento Ambiental , Material Particulado , Emissões de Veículos
12.
Eur J Pharmacol ; 868: 172881, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31866405

RESUMO

Psoriasis is a chronic, inflammatory skin disease with high incidence and high rates of relapse, for which no satisfactory treatments are currently available. Yes-associated protein (YAP) is highly expressed in psoriasis and may regulate the proliferation and apoptosis of keratinocytes. Danshen is a traditional Chinese medicine, commonly used in the treatment of psoriasis. Danshensu is the most abundant water-soluble component of Danshen, but its therapeutic mechanism is still unclear. In this study, MTT was used to detect the effects of different danshensu concentrations (0.125, 0.25, 0.5 mmol/l) on the proliferation of an M5-based psoriasis cell model. The effects of danshensu on cell cycle and apoptosis were detected by flow cytometry. Cyclins and apoptosis-related proteins were evaluated by Western blot. Danshensu (20, 40, 80 mg/kg/day) was administered intraperitoneally to the imiquimod (IMQ) psoriasis mouse model. After 7 days, the expression of YAP in the lesions was detected by immunohistochemistry and Western blot. We found that danshensu reduced the expression of YAP in the M5 psoriasis cell model, inhibited cell proliferation, induced cell cycle arrest in G0/G1 phase, and promoted cell apoptosis. All these effects were partly reverted by YAP overexpression. The skin lesions of IMQ mice were thinned and the scales reduced after intragastric administration of danshensu, which also resulted in dose-dependent inhibition of YAP expression. We concluded that danshensu prevents abnormal epidermis proliferation in psoriasis possibly by modulating YAP expression. Our work can provide a theoretical basis for the clinical application of Danshen in the treatment of psoriasis.

13.
Bioinformatics ; 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31794005

RESUMO

MOTIVATION: RNA 5-methylcytosine (m5C) is a type of post-transcriptional modification that may be involved in numerous biological processes and tumorigenesis. RNA m5C can be profiled at single-nucleotide resolution by high-throughput sequencing of RNA treated with bisulfite (RNA-BisSeq). However, the exploration of transcriptome-wide profile and potential function of m5C in splicing remains to be elucidated due to lack of isoform level m5C quantification tool. RESULTS: We developed a computational package to quantify Epitranscriptomal RNA m5C at the transcript isoform level (named Episo). Episo consists of three tools, mapper, quant and Bisulfitefq, for mapping, quantifying, and simulating RNA-BisSeq data, respectively. The high accuracy of Episo was validated using an improved m5C-specific methylated RNA immunoprecipitation (meRIP) protocol, as well as a set of in silico experiments. By applying Episo to public human and mouse RNA-BisSeq data, we found that the RNA m5C is not evenly distributed among the transcript isoforms, implying the m5C may subject to be regulated at isoform level. AVAILABILITY: Episo is released under the GNU GPLv3+ license. The resource code Episo is freely accessible from https://github.com/liujunfengtop/Episo (with Tophat/cufflink) and https://github.com/liujunfengtop/Episo/tree/master/Episo_Kallisto (with Kallisto). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

14.
Phys Rev Lett ; 123(20): 206801, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31809113

RESUMO

We study the tunneling through a two-dimensional topological insulator with topologically protected edge states. It is shown that the tunneling probability can be quantized in a broad parameter range, 0 or 1, tuned by an applied transverse electric field. Based on this field-effect tunneling, we propose two types of topological transistors based on helical edge or interface states of quantum spin Hall insulators separately. The quantized tunneling conductance is obtained and shown to be robust against nonmagnetic disorders. Usually, the topological transition is necessary in the operation of topological transistors. These findings provide a new strategy for the design of topological transistors without topological transitions.

15.
Circ Cardiovasc Qual Outcomes ; 12(12): e005610, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31830825

RESUMO

BACKGROUND: Little is known about long-term trends in outcomes of patients with ischemic stroke in China. We aimed to assess longitudinal trends in these outcomes over the past 15 years in China and explore possible factors behind the trends. METHODS AND RESULTS: Patients with ischemic stroke admitted to the Department of Neurology at West China Hospital were prospectively and consecutively enrolled in a central registry since 2002, and the present study analyzed data from those admitted to hospital within 7 days of stroke during the period 2002 to 2016. Patients were binned into three 5-year intervals for temporal analysis. Death, disability, and death/disability at 3 and 12 months after stroke were compared among the time intervals across the entire sample and in subsets stratified by age (<65 or ≥65 years). To explore the possible factors related to the trends in outcomes, interaction between the factors and time on outcomes was entered separately into the multivariable logistic regression model. Of 6462 patients with ischemic stroke in the final analysis, 3837 (59.4%) were men, and mean age was 64.2 years (SD, 13.7). Mean age at stroke onset and National Institutes of Health Stroke Scale score at admission decreased significantly during the 15-year period (P<0.001). Between 2002 to 2006 and 2012 to 2016, cumulative incidences declined significantly for death at 3 months (from 9.6% to 6.4%), disability at 3 months (from 36.8% to 28.7%), and death/disability at 3 months (from 42.9% to 33.3%), as well as for death at 12 months (from 15.9% to 10.7%), disability at 12 months (from 23.2% to 17.6%), and death/disability at 12 months (from 35.4% to 26.4%; all P<0.001). The decreases in disability and death/disability at 3 and 12 months between 2002 to 2006 and 2012 to 2016 remained significant after adjusting for confounders, and the results were similar for the entire cohort and for subgroups of patients <65 or ≥65 years. Only interactions of National Institutes of Health Stroke Scale score on admission and time period (2012-2016) were found to significantly correlate with disability and death/disability at 3 and 12 months (all P≤0.03). CONCLUSIONS: Our study from a large medical center in southwest China suggests that since 2002, risks of disability and death/disability at 3 and 12 months after ischemic stroke have declined. This appears to be due, at least in part, to a significant decline in National Institutes of Health Stroke Scale score on admission, which may reflect greater public awareness of stroke detection, willingness to seek medical attention, and ease of access to healthcare infrastructure. The factors behind this apparent improvement require further study.

16.
Huan Jing Ke Xue ; 40(9): 3973-3981, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854859

RESUMO

Nitrous acid (HONO) is easily photolyzed with the production of·OH, which plays an important role in the formation of regional secondary pollution. In China, research of HONO observation is concentrated mainly in urban areas and is rarely reported in rural areas. In our study, a one-month HONO field observation was conducted at the Station of Rural Environment, Chinese Academy of Sciences (Dongbaituo Village, Wangdu County, Hebei Province) in November 2017 using the long path absorption photo meter (LOPAP). The concentration, variety characteristics, and budget of HONO was studied. During the observation period, HONO exhibited pronounced diurnal variation with low concentrations in the day and high concentration in the evening. The highest concentration at night was about 3.70×10-9, and the lowest concentration at noon was about 0.10×10-9, indicating the presence of a strong source of HONO in rural areas. The CO concentration increased significantly before and after heating, whereas the HONO concentration did not change significantly, indicating that heating combustion contributed less to HONO, Direct emission of motor vehicles at night contributed 23.20% and 31.20% to HONO in polluted and clean weather conditions, respectively, indicating the presence of strong sources of HONO in polluted weather conditions. The average formation rate of HONO at night from homogeneous reaction of·OH and NO could reach 0.40×10-9 h-1, which is 0.67 times higher than that of heterogeneous reaction of NO2 (0.24×10-9 h-1), indicating that the homogeneous reaction of·OH and NO is the main source of HONO at night. HONO has a strong unknown source in the daytime with an intensity reaching 1.37×10-9 h-1, which contributes about 50% to HONO.

18.
Environ Sci Technol ; 53(24): 14709-14715, 2019 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-31751126

RESUMO

Since triphenyl phosphate (TPhP) elicits both antiestrogenic activities via blocking the estrogen receptor (ER) and estrogenic activity by elevating 17ß-estradiol (17ß-E2) synthesis, its adverse effect on female reproduction is uncertain. In this study, we exposed Japanese medaka to TPhP at 131, 363, and 1773 ng/L for 100 days following hatching. TPhP significantly induced ovary retardation in all exposure groups (incidence: from 11.9 to 37.8%) and reduced egg production by 38.9 and 50.9% in the 363 and 1773 ng/L exposure groups, respectively. Vitellogenin (vtg) transcription was significantly downregulated by 35.4-57.4% after TPhP exposure, explaining the ovary retardation. Considering that 17ß-E2 was only significantly decreased in the 1773 ng/L exposure group, ER antagonism could be the dominant contributor to the inhibition of vtg transcription and female reproductive toxicity of TPhP. As 4-hydroxyphenyl diphenyl phosphate, a metabolite of TPhP, was detected in livers with similar concentration [68.4-1237 ng/g lipid weight (lw)] to that of TPhP (485-1594 ng/g lw) and elicited medaka ER antagonistic activity (50% inhibitory concentration = 78.1 µM), TPhP and its metabolite should both contribute to the reproductive inhibition. We demonstrate that TPhP at environmentally relevant concentrations is toxic to female reproduction, which poses an ecological risk to wild fish at the population level.

19.
J Cell Physiol ; 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31674024

RESUMO

Endometritis is an inflammatory change in the structure of the endometrium due to various causes and is a common cause of infertility. Studies have confirmed that microRNAs (miRNAs) play a key regulatory role in various inflammatory diseases. However, the miRNA-mediated mechanism of endometrial inflammation induced by lipopolysaccharides (LPS) remains unclear. In this study, real-time quantitative polymerase chain reaction, Western blot analysis, immunofluorescence and Rac family small GTPase 1 (Rac1) interference were used to reveal the overexpression of miR-488 in the LPS-induced bovine uterus, and the effect of protein kinase B κ-light chain enhancement of the nuclear factor-activated B cells (AKT/NF-κB) pathway in intimal epithelial cells. The results showed that the expression of inflammatory cytokines such as interleukin-1ß (IL-1ß), IL-6, and tumor necrosis factor-α in the experimental group was significantly lower than that in the control group when miR-488 was overexpressed. Similar results were observed in the expression levels of p-AKT, p-IKK, and p-p65 proteins. In addition, the dual-luciferase reporter system confirmed that miRNA-488 may directly target the 3'-untranslated region of Rac1. In turn, the expression of Rac1 was inhibited. Moreover, the nuclear translocation of NF-κB was inhibited, and meanwhile, the accumulation of reactive oxygen species (ROS) in the cells was reduced. Thus, we provide basic data for the negative regulation of miR-488 in LPS-induced inflammation by inhibiting ROS production and the AKT/NF-kB pathway in intimal epithelial cells.

20.
Environ Sci Technol ; 53(22): 13238-13245, 2019 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-31633339

RESUMO

Given the lack of understanding of the complex physiochemical and environmental processes of persistent organic pollutants (POPs) in the Arctic and around the globe, atmospheric models often yield large errors in the predicted atmospheric concentrations of POPs. Here, we developed a recurrent neural network (RNN) method based on nonparametric deep learning algorithms. The RNN model was implemented to predict monthly air concentrations of polycyclic aromatic hydrocarbons (PAHs) at the high Arctic monitoring station Alert. To train the RNN system, we used MODIS satellite remotely sensed forest fire data, air emissions, meteorological data, sea ice cover area, and sampled PAH concentration data from 1996 to 2012. The system was applied to forecast monthly PAH concentrations from 2012 to 2014 at the Alert station. The results were compared with monitored PAHs and an atmospheric transport model (CanMETOP) for POPs. We show that the RNN significantly improved PHE and BaP predictions from 2012 to 2014 by 62.5 and 91.1%, respectively, compared to CanMETOP predictions. The sensitivity analysis using the Shapley value reveals that air emissions determined the magnitude of PAH levels in the high Arctic, whereas forest fires played a significant role in the changes in PAH concentrations in the high Arctic, followed by air temperature and meridional wind fields.


Assuntos
Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Regiões Árticas , Aprendizado Profundo , Monitoramento Ambiental
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA