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1.
Life Sci ; : 118015, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32629000

RESUMO

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Cardiac fibrosis is the scarring process occurs commonly with CVDs impairing the function and structure of heart. Herein, we investigated the role of circPAN3 in the pathogenesis of cardiac fibrosis. METHODS: A rat myocardial infarction (MI) model was constructed to evaluate the role of circPAN3. Expression of circPAN3 in MI was determined, and si-circPAN3 was applied to verify its profibrotic effects. With an in vitro model, cardiac fibroblasts were stimulated by transforming growth factor beta 1 (TGFß1). Immunofluorescent staining was employed to assess the fibrosis-related markers, as well as autophagy activity. CCK-8 and transwell assays were performed to determine cell proliferation and migration. Luciferase reporter assay and RNA pull-down were subjected to verify the interaction of circPAN3/miR-221. The enrichment of FoxO3 on the promoter region of ATG7 was detected using CHIP assay. RESULTS: Elevated circPAN3 was found in rat MI heart tissue, of which knockdown attenuated cardiac fibrosis after MI. In an in vitro model exposing with TGFß1, increasing cell proliferation and migration were observed, whereas these effects were abolished by circPAN3 knockdown, as well as autophagy activity. miR-221 was identified as a target to be involved in circPAN3-mediated cardiac fibrosis after MI. miR-221 negatively regulated FoxO3, thus causing the inhibition of ATG7 transcription. The regulatory network of circPAN3/miR-221/FoxO3/ATG7 in cardiac fibrosis was further determined in vivo. CONCLUSION: circPAN3 exhibited profibrotic effects during autophagy-mediated cardiac fibrosis via miR-221/FoxO3/ATG7 axis, which may serve as potential biomarkers for cardiac fibrosis therapeutics.

2.
Rev Sci Instrum ; 91(3): 033105, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32259982

RESUMO

The absolute response of the GE Amersham Typhoontm imaging plate scanner is studied in this paper. The sensitivity function of the scanner with different photomultiplier tube voltages was obtained by using a pre-calibrated Cu Kα x-ray tube. The results showed that the sensitivity function decreases exponentially with higher voltage and is also affected by the scanning pixel size. The spatial resolution and the fading effect of the imaging plate system on x rays were also investigated and compared with the previous scanner models.

3.
Mater Sci Eng C Mater Biol Appl ; 111: 110858, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32279759

RESUMO

Ca10(PO4)6(OH)2 doped with GdPO4 (HA-GP) was synthesized by a sol-gel technique, and its phase composition depended on the GdPO4 content. At low doping levels, the phase structure was composed of hydroxyapatite and some Ca3(PO4)2, and the content of the latter decreased with the doping content; when the doping content reached to 15 mol%, however, the Ca3(PO4)2 amount revealed a significant increase, and GdPO4 turned to be precipitated. With the addition of GdPO4, the microstructure of HA-GP pellets became dense, and the grain size decreased. GdPO4 doping enhanced the hardness of HA-GP due to a grain size effect. With increasing the doping content, the toughness increased initially followed by a decrease, and 7.5 mol% doping (HA-GP7.5) led to the highest toughness. Magnetization tests revealed that GdPO4 had paramagnetic behavior, which made it suitable for magnetic resonance imaging (MRI) contrast agent. The MRI contrast behavior of HA-GP7.5 was investigated. With the increase of the concentration, the T1 weighted MR image revealed enhanced brightness, while the brightness of T2 weighted MR images reduced gradually. Considering the phase structure, mechanical properties, and MRI contrast behavior, HA-GP7.5 might have a potential to be used in clinical medicine.

4.
Sci Total Environ ; 720: 137617, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32325589

RESUMO

The measurement of volatile organic compounds (VOCs) was carried out using an online GC-FID/MS at a rural site in North China Plain from 1 Nov. 2017 to 21 Jan. 2018. Their concentrations, emission ratios and source apportionment are investigated. During the entire experiment period, the average mixing ratio of VOCs was 69.5 ± 51.9 ppb, among which alkanes contributed the most (37% on average). Eight sources were identified in the non-negative matrix factorization (NMF) model as short-chain alkanes (13.3%), biomass burning (4.6%), solvent (10.8%), industry (3.7%), coal combustion (41.1%), background (4.5%), vehicular emission (7.7%) and secondary formation (14.2%). In addition to the formation of OVOCs through photochemical reactions, the primary sources, such as coal combustion, biomass burning, vehicular emission, solvent and industry, can also contribute to OVOCs emissions. High OVOCs emission ratios thus were observed at Wangdu site. Primary emission was estimated to contribute 50%, 45%, 73%, 77%, 40%, and 29% on average to acrolein, acetone, methylvinylketone (MVK), methylethylketone (MEK), methacrolein and n-hexanal according to NMF analysis, respectively, which was well consistent with the contribution from photochemical age method. Secondary organic aerosol formation potential (SOAFP) was evaluated by SOA yield, which was significantly higher under low-NOx condition (13.4 µg m-3 ppm-1) than that under high-NOx condition (3.2 µg m-3 ppm-1). Moreover, the photochemical reactivity and sources of VOCs showed differences in seven observed pollution episodes. Among, the largest OH loss rate and SOAFP were found in severe pollution plumes, which were induced primarily by coal combustion. Therefore, mitigation strategies for severe pollution formation should focus on reducing coal combustion emitted VOCs that lead to SOA formation.

5.
Medicine (Baltimore) ; 99(16): e19699, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32311950

RESUMO

This study aimed to identify the correlation of contradiction between DAPT score and PRECISE-DAPT score with the severity of coronary lesion in acute coronary syndromes (ACS).In total, 458 patients with ACS after a percutaneous coronary intervention (PCI) who had tolerated 1-year uneventful dual antiplatelet therapy (DAPT) were enrolled and divided into groups based on the Gensini score, number of stenosed vessels, and left main (LM) disease. Both DAPT score and PRECISE-DAPT score were calculated and the proportion of patients receiving conflicting recommendations from each score was compared among the groups.DAPT score as well as the proportion of patients with DAPT score ≥2 were associated with the Gensini score and the number of stenosed vessels. Similarly, PRECISE-DAPT score as well as the proportion of patients with PRECISE-DAPT score ≥25 were associated with the Gensini score and the number of stenosed vessels. The proportion of patients with DAPT score ≥2 along with PRECISE-DAPT score ≥25 were associated with Gensini score, but they had no significant association with the number of stenosed vessels (P = .006 and P = .075, respectively). None of those aforementioned items were associated with LM disease.The inconsistencies of DAPT scores and PRECISE-DAPT scores are frequent and associated with the severity of coronary disease, represented by the Gensini score. Appropriate clinical decisions should be individualized.


Assuntos
Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/terapia , Síndrome Coronariana Aguda/patologia , Idoso , Estenose Coronária/diagnóstico , Terapia Antiplaquetária Dupla , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Intervenção Coronária Percutânea , Hemorragia Pós-Operatória/diagnóstico , Estudos Retrospectivos , Índice de Gravidade de Doença , Stents , Resultado do Tratamento
6.
J Environ Manage ; 266: 110577, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32310119

RESUMO

Recycling of plastics from e-waste can conserve resources, however, aging during the use of plastic products can cause the migration of heavy metals in additives. This study presents a methodology for evaluating the risks of heavy metals in waste plastic secondary products during long term use associated with heavy metal migration. The study processes were investigated by: (1) recycling waste plastics and producing secondary products; (2) thermal aging of secondary products; and (3) toxic leaching used to quantitatively analyse the dissolution of heavy metals. Combined with the changes in mechanical properties and microstructure, the effect of aging on the migration of heavy metals was observed. The results showed that the polymer appeared to delaminate, the adhesion of waste plastics to additives decreased, and the mechanical properties clearly decreased after the thermal aging experiment. Leaching experiments showed that the leached concentrations of Ni, Cu, Zn, Pb, and Sb in the three types waste plastic products increased over time. After 8 d of aging, the leached concentrations of Ni, Sb, and Pb exceeded the third, fourth, and third class of the groundwater quality standard, respectively. Specifically, the concentrations of Sb were 141, 289, and 21.1 times higher than the maximum permissible level. Therefore, management hierarchy and safe environmental recycling methods should be developed to reduce the risk of heavy metals in waste plastic secondary products.


Assuntos
Resíduo Eletrônico , Metais Pesados , Poluentes do Solo , Plásticos , Reciclagem
7.
Sci Total Environ ; 720: 137536, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32145623

RESUMO

In recent years, PM2.5 and O3 pollutions are prevalent in the atmosphere in Beijing. The study on pollution characteristics of VOC, which are important precursors of O3 and secondary organic aerosols (SOA) contributing PM2.5, is of great significance for providing a reference to guide its reduction policy formulation. Herein, the seasonal variation of atmospheric VOCs and meteorological conditions at the sampling frequency of 1 time per hour were continuously measured from March 2016 to January 2017 in Beijing. Using the collected data combined with multiple models, the role of VOCs in SOA and O3 production was investigated. Alkanes were the most abundant species, contributing 54.1-64.7% of the total VOC concentration for four seasons, followed by aromatics, alkenes and acetylene. The SOA potential (SOAP) was highest in winter at 2885.1 µg m-3, followed by autumn, spring and summer. Aromatics were the main contributors to SOAP, accounting for ~98.2% of the total SOAP during the entire observation period. The empirical kinetic modeling approach results showed that O3 production featured the VOC-limited regime in Beijing. Alkenes and aromatics were major contributors to O3 formation potential (OFP), accounting for 33.1-45.6% and 27.2-45.2%, respectively, particularly ethylene and m,p-xylene. Positive matrix factorization results indicated that motor vehicle exhaust was still the largest local source of VOCs, but its proportion was considerably reduced. The potential source contribution function results revealed that regional transport sources of VOC pollution in Beijing mainly came from the northwest and southern areas. Thus, to control PM2.5 and O3 pollution in Beijing, the restriction of alkenes and aromatics emission, accompanied by regional cooperation combined with local control, is essential.

8.
BMJ Open ; 10(2): e033408, 2020 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-32114467

RESUMO

OBJECTIVES: To determine the independent relationship between depressive symptoms and arterial stiffness in the general Chinese population, and to explore possible interactive factors in the relationship. DESIGN: A cross-sectional study. SETTING AND PARTICIPANTS: Consecutive participants who received routine health physical examination in an affiliated hospital of a comprehensive university in Hunan Province, China, between September 2013 and March 2014 were examined. After exclusion of subjects not meeting the criteria, a total of 1334 subjects aged 22-77 years were recruited for final analysis. MEASURES: The Patient Health Questionnaire-9 was employed to assess the degree of depressive symptoms: 0-4 no depressive symptoms, 5-9 mild depressive symptoms and 10-27 moderate to severe depressive symptoms. Brachial-ankle pulse wave velocity (baPWV) was measured to determine arterial stiffness. RESULTS: There was a slight increase in baPWV across elevated degrees of depressive symptoms (p=0.025). Multivariate linear regression analysis revealed that mild depressive symptoms and moderate to severe depressive symptoms were independently associated with baPWV compared with no depressive symptoms after adjusting for baseline confounders (beta-coefficient: 40.3, 95% CI 6.6 to 74.1; beta-coefficient: 87.7, 95% CI 24.0 to 151.5, respectively). Further stratified analyses indicated that the relationship between degree of depressive symptoms and baPWV was predominant in subjects who had normal or normal-high blood pressure, or combined with hypertension (p for interaction=0.016), or in subjects with diabetes mellitus (p for interaction=0.004), examined in multivariate linear regressions. In addition, after adjustment, a significant association between moderate to severe depressive symptoms and baPWV was also found in female subjects younger than 60 years, although the interactive effect was not significant (p for interaction=0.056). CONCLUSIONS: Depressive symptoms are independently associated with arterial stiffness, especially in subjects whose blood pressures are beyond the optimal range and combined with diabetes mellitus.

9.
J Comput Chem ; 41(7): 731-738, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31743465

RESUMO

Based on the molecular dynamics software package CovalentMD 2.0, the fastest molecular dynamics simulation for covalent crystalline silicon with bond-order potentials has been implemented on the third highest performance supercomputer "Sunway TaihuLight" in the world (before June 2019), and already obtained 16.0 Pflops (1015 floating point operation per second) in double precision for the simulation of crystalline silicon, which is recordly high for rigorous atomistic simulation of covalent materials. The simulations used up to 160,768 64-core processors, totally nearly 10.3 million cores, to simulate more than 137 billion silicon atoms, where the parallel efficiency is over 80% on the whole machine. The running performance on a single processor reached 15.1% of its theoretical peak at highest. The longitudinal dimension of the simulated system is far beyond the range with scale-dependent properties, while the lateral dimension significantly exceeds the experimentally measurable range. Our simulation enables virtual experiments on real-world nanostructured materials and devices for predicting macroscale properties and behaviors from microscale structures directly, bringing about many exciting new possibilities in nanotechnology, information technology, electronics and renewable energies, etc. © 2019 Wiley Periodicals, Inc.

10.
Chemosphere ; 245: 125645, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31864064

RESUMO

Recycling is the primary method to handle electronic waste plastics, however, little attention has been paid to the risk posed by heavy metal migration in waste plastic products. The effect of multistage recycling processes on heavy metal migration and the environmental risk posed by heavy metals during recycling processes were investigated by: (1) Recycling waste plastics and determining the heavy metal contents in secondary products; (2) Using toxic leaching experiments to assess environmental risks of heavy metal migration in secondary products; and (3) Evaluating the effect of recycling processes on the mechanical properties and microstructure of plastics. Results showed that the contents of some harmful heavy metals in processed products exceeded the Safety of Toys Standard. Toxic leaching tests showed that Ni, Cu, Zn, Pb, and Sb migrated outward during secondary products use. With increased recycling times, concentrations of migrated Ni, Cu, Zn, Pb, and Sb increased, and the leached concentrations exceeded the limits stipulated in the Groundwater Quality Standard. Increased recycling times also accelerated waste plastics aging and caused the deterioration of mechanical properties. Furthermore, adhesion between layers decreased, stratification and cracking in polymers appeared, and adhesion of waste plastics to additives decreased. Therefore, the environmental risks of waste plastic recycling should be carefully considered.


Assuntos
Resíduo Eletrônico/análise , Metais Pesados/análise , Plásticos/análise , Reciclagem , Água Subterrânea/química , Humanos , Laboratórios , Polímeros , Solo/química , Poluentes do Solo/análise
11.
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.

12.
Mar Pollut Bull ; 149: 110569, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546109

RESUMO

This study involved an assessment of the levels of microplastic pollution in seven small-scale estuaries in Shanghai for the first time. The abundance of microplastics ranged from 13.53 ±â€¯4.6 to 44.93 ±â€¯9.41 particles L-1, with a mean abundance of 27.84 ±â€¯11.81 particles L-1. Microplastics collected from samples were classified into four types (fiber, film, granule, and fragment), and granules were the most abundant type. Up to 99.5% of microplastics were <2 mm in diameter. The microplastics had a variety of colors, with black being the dominant color. Polypropylene (37.5%) and polyethylene (50%) were the main types of microplastic component validated. Our study showed severe microplastic pollution in small-scale estuaries, and the associated rivers need urgent attention for microplastic pollution prevention.


Assuntos
Microplásticos/análise , Poluentes Químicos da Água/análise , China , Cor , Monitoramento Ambiental , Estuários , Microplásticos/química , Polietileno/análise , Polipropilenos/análise , Rios
13.
Waste Manag ; 98: 21-28, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421486

RESUMO

The low bioleaching efficiency of Acidithiobacillus ferrooxidans results in its sparse industrial application for metal extraction from waste printed circuit boards (WPCBs). To improve the bioleaching efficiency of Acidithiobacillus ferrooxidans, we propose the use of mechanical activation to dispose WPCBs prior to performing bioleaching. Response surface methodology (RSM), scanning electron microscope- energy dispersive spectrometer (SEM-EDS), and laser particle size analyzer (LPSA) were used to optimize and analyze the mechanical activation process, respectively. The optimal conditions for mechanical activation was a milling time of 2 h, milling speed of 340 r min-1, and ball material ratio (w/w) of 10/1; the bioleaching rates of Cu, Ni, and Zn were 94.33%, 90.69%, and 90.78%, respectively. The bioleaching rates of Cu, Ni, and Zn were 74.75%, 70.46%, and 71.05%, respectively, without mechanical activation pretreatment. SEM-EDS and LPSA analyses indicated that mechanical activation could lead to a smaller particle size and expose wrapped metals, thus improving the bioleaching efficiency oyf tyhe metals inside the WPCBs. The electrode potential of the metals was likely changed by the mechanical activation, resulting in an improvement of their bioleaching efficiency. Additionally, the bioleaching rates of Pb, Cr, and Cd after mechanical activation pretreatment were 10.29%, 74.89%, and 54.12%, respectively. Contrastingly, the bioleaching rates of Pb, Cr, and Cd without mechanical activation pretreatment were 5.18%, 59.97%, and 37.12%, respectively. Thereinto, the precipitation of PbSO4 may result in a decrease of leached Pb. We propose a mechanical activation process for improving the bioleaching efficiency of metals from WPCBs.


Assuntos
Acidithiobacillus , Metais
14.
J Environ Sci (China) ; 84: 155-165, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31284907

RESUMO

Nitrogen dioxide (NO2) is an important substance in atmospheric photochemical processes and can also be absorbed by plants. NO2 fluxes between the atmosphere and P. nigra seedlings were investigated by a double dynamic chambers method in Beijing from June 15 to September 3, 2017. The range of NO2 exchange fluxes between P. nigra seedlings and the atmosphere was from -14.6 to 0.8 nmol/(m2·sec) (the positive data represent NO2 emission from trees, while the negative values indicate absorption). Under ambient concentrations, the mean NO2 flux during the fast-growing stage (Jun. 15-Aug. 4) was -3.0 nmol/(m2·sec), greater than the flux of -1.5 nmol/(m2·sec) during the later growth stage (Aug. 8-Sept. 3). The daily exchange fluxes of NO2 obviously fluctuated. The fluxes were largest in the morning and decreased gradually over time. Additionally, the NO2 fluxes were larger under high light intensities than under low light intensities during the whole growth period. The effects of temperature on NO2 fluxes were different under two growth periods. The NO2 exchange fluxes were larger in a range of temperatures close to 44°C in the fast-growing stage, whereas there were no evident differences in NO2 exchange fluxes under widely differing temperatures in the later growth stage. Under polluted conditions, the uptake ability of NO2 was weakened. Additionally, the compensation point of NO2 was 5.6 ppb in the fast-growing stage, whereas it was 1.4 ppb in the later growth stage. The deposition velocities of NO2 were between 0.3 and 2.4 mm/sec.


Assuntos
Dióxido de Nitrogênio/metabolismo , Plântula/metabolismo , Atmosfera , Umidade , Pinus , Estações do Ano
15.
Waste Manag ; 94: 49-57, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31279395

RESUMO

Thermal treatment has been proved to be an efficient and promising method for organics removal from LCD panels and for resource recycling. Considering with the toxic metals contained in LCD panels and their potential risk, it is necessary to study and evaluate the metals behavior and potential risk associated with the thermal treatment of LCD panels. In this study, the migration and transformation behavior of ten metals (Cr, As, Al, In, Ni, Cu, Zn, Cd, Fe, Sn) in LCD panels were investigated during thermal treatment, as well as their potential environmental risk and leaching toxicity in solid residue were evaluated. Results showed that Cr, Ni, In, Cu and Fe exhibit obvious migration behavior from solid into gas phase/fly ash during thermal treatment, with the maximum migration rate of 52.8%, 54.7%, 37.7%, 30.8%, and 34.9% respectively under the experimental condition. Speciation transformation for the metals of Cr, Ni, In, Cu, Fe and Zn was also observed in solid residue after thermal treatment, which leads to the ecological risk increase of Cu, In and contamination risk increase of Fe. Meanwhile, the leachable concentration and leaching toxicity of Cu and Ni in solid residue showed increasing trend after thermal treatment. The results indicate that attentions should be paid on the emission control of Cr, Ni, In, Cu, Fe during thermal treatment of LCD panel scraps. Environmental risk of Cu, In, Fe and the leaching toxicity of Ni in solid residue after thermal treatment should also be concerned.


Assuntos
Cristais Líquidos , Metais Pesados , Cinza de Carvão
16.
Sci Total Environ ; 692: 82-88, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31336304

RESUMO

NO2- plays a crucial role in regulating N2O formation from the soil, while how it affects the production of soil N2O is still not well understood. In this study, N2O and NO emissions from an agricultural field of the North China Plain (NCP) were comparatively investigated under five different fertilizer treatments (NH4+, NO3-, NO2-, NH4+ + NO2- and NO3- + NO2-). Additionally, soil NH4+, NO2- and NO3- concentrations and the abundance of functional genes associated with nitrogen cycling were also analyzed in the incubation experiment. The results showed that the N2O average fluxes from the complex treatments of NO2- + NO3- were 1.4-2.4 times the sum of those from the separate treatments of NO2- and NO3- whereas from the complex treatments of NO2- + NH4+ were a factor of 1-1.4 larger than those from the separate treatments of NO2- and NH4+, indicating the coupling interaction of NO2- with NH4+ or NO3- makes a remarkable contribution to N2O emission from the soil. Significant reduction of the activity of N2O reductase was found in the soil with the addition of NO2-, which favored the accumulation of N2O formed through nitrification of NH4+ and denitrification of NO2-, resulting in relatively high N2O emissions from the complex treatments. As the intermediate product of nitrification and denitrification, NO2- produced is also expected to interact with NH4+ or NO3- to promote N2O emission from the soil, especially during fertilization events when NO2- is easily accumulated due to the acceleration of the nitrification and denitrification processes.

17.
Artigo em Inglês | MEDLINE | ID: mdl-31142013

RESUMO

In this study, a nonlinear inexact two-stage management (NITM) model is proposed for optimal agricultural irrigation water management problems under uncertainty conditions. The model is derived from incorporating interval parameter programming (IPP), two-stage stochastic programming (TSP) and quadratic programming (QP) within the agricultural water management model. This model simultaneously handles uncertainties not only in discrete intervals, but also in probability distributions, as well as nonlinearity in the objective function. A concept of the law of diminishing marginal utility is introduced to reflect the relationship between unit benefits and allocated water, which can overcome the limitation of general TSP framework with a linear objective function. Moreover, these inexact linear functions of allocated water can be obtained by an interval regression analysis method. The model is applied to a real-world case study for optimal irrigation water allocation in midstream area of the Heihe River Basin in northwest China. Two Heihe River ecological water diversion plans, i.e. the original plan and an improved plan, will be used to determine the surface water availabilities under different inflow levels. Four scenarios associated with different irrigation target settings are examined. The results show that the entire study system can arrive at a minimum marginal utility and obtain maximum system benefits when optimal irrigation water allocations are the deterministic values. Under the same inflow level, the improved plan leads to a lower water shortage level than that of the original plan, and thus leads to less system-failure risk level. Moreover, the growth rate of the upper bound of economic benefits between each of two scenarios based on the improved plan are greater than that from the original plan. Therefore, these obtained solutions can provide the basis of decision-making for agricultural water allocation under uncertainty.


Assuntos
Irrigação Agrícola/métodos , Modelos Teóricos , Rios , Abastecimento de Água , China , Tomada de Decisões , Ecossistema , Probabilidade , Incerteza , Poluição da Água
18.
Sci Total Environ ; 659: 621-631, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31096391

RESUMO

HONO (nitrous acid) is a crucial precursor for tropospheric OH radicals, and its sources are not well understood. In the past decade, soil was proven to be a potential source for HONO. However, more field measurements of soil HONO emission flux are needed to explore the mechanism and its impact on regional air quality. Here, we developed a system based on twin open-top chambers (OTCs) and wet chemical methods to measure HONO emission flux from agricultural soil in the North China Plain (NCP). The performance of the OTC system was tested under laboratory and field measurement conditions. The results showed that the system could reflect the strength (>90%) and variation of gas emission with an average residence time of 4-5 min. The greenhouse effect and chemical reaction interference in the chamber was proven to have no significant influence on the HONO flux measurement. Field measurement revealed that agricultural soil before fertilization was an important source of HONO. The emission flux showed radiation-dependent or temperature-dependent variation, with a peak of 3.21 ng m-2 s-1 at noontime that could account for approximately 67 pptv h-1 of the missing HONO source under an assumed mixing layer height of 300 m. Fertilization substantially accelerated HONO emission, which was rationally attributed to biological processes including nitrification. Considering the high fertilization rate in the NCP and other similar regions in China, HONO emission from agricultural soil likely has enormous impact on regional photochemistry and air quality, suggesting that more research should be conducted on this aspect.

19.
J Environ Sci (China) ; 80: 316-326, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30952349

RESUMO

The efficient maintenance of the activity of excised branches is the powerful guarantee to accurately determine gas exchange flux between the detached branches of tall trees and the atmosphere. In this study, the net photosynthetic rate (NPR) of the excised branches and branches in situ were measured simultaneously by using two photosynthetic instruments to characterize the activity of the excised branches of Phyllostachys nigra. The ratio of normalized NPR of excised branches to NPR in situ was used to assess the photosynthetic activity of detached branches. Based on photosynthetic activity, an optimal hydroponics protocol for maintaining activity of excised P. nigra branches was presented: 1/8 times the concentration of Gamborg B5 vitamin mixture with pH = 6. Under the best cultivation protocol, photosynthetic activity of excised P. nigra branches could be maintained more than 90% within 6 hr in the light intensity range of 200-2000 µmol/(m2·sec) and temperature range of 13.4-28.7°C. The nitrogen dioxide (NO2) flux differences between in situ and in vitro branches and the atmosphere were compared using double dynamic chambers. Based on the maintenance method of excised branches, the NO2 exchange flux between the excised P. nigra branches and the atmosphere (from -1.01 to -2.72 nmol/(m2·sec) was basically consistent with between the branches in situ and the atmosphere (from -1.12 to -3.16 nmol/(m2 sec)) within 6 hr. Therefore, this study provided a feasible protocol for in vitro measurement of gas exchange between tall trees and the atmosphere for a period of time.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Dióxido de Nitrogênio/análise , Prunus/fisiologia , Atmosfera/química , Fotossíntese , Árvores
20.
Aging Dis ; 10(2): 231-248, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31011475

RESUMO

Phenotypic transformation of vascular smooth muscle cells (VSMCs) contributes to vascular remodeling in hypertension. High mobility group box-1 (HMGB1) has been reported to be involved in several pathogenic processes including VSMC proliferation and migration. The present study was designed to determine the role of HMGB1 in VSMC phenotypic transformation in hypertension. First, we demonstrated that HMGB1 was elevated in a model of Ang II-induced VSMC phenotypic transformation, which showed down-regulation of contractile proteins and up-regulation of synthetic proteins. Knockdown of HMGB1 and losartan could block the phenotypic transformation. Next, we identified three potential miRNAs for upstream regulation of HMGB1 by bioinformatic analysis; only miR-181b-5p was significantly down-regulated in Ang II-treated cells. Co-treating the cells with miR-181b-5p mimics suppressed HMGB1 expression as well as the phenotypic transformation, migration, and proliferation. Furthermore, the luciferase reporter gene assay confirmed the direct interaction between miR-181b-5p and HMGB1. Finally, to extend these cell-based studies to clinical patients, we demonstrated that plasma miR-181b-5p levels were decreased, while Ang II and HMGB1 levels, as well as the intima-media thickness (IMT) were increased in hypertensive patients; these effects were reversed following the administration of angiotensin receptor blockers. Based on these observations, we conclude that the down-regulation of miR-181b-5p leads to the elevation of HMGB1 levels in hypertensive patients, which accounts, at least partially, for VSMCs phenotypic transformation and vascular remodeling. Our findings also highlight that the plasma levels of miR-181b-5p and HMGB1 may serve as novel biomarkers for vascular remodeling in the hypertensive patients.

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