247 research outputs found
Source Apportionment of Ozone and Its Health Effects in North China Plain and Southeast U.S.
Ground-level ozone (O3), as one of six common air pollutants set by National Ambient Air Quality Standards from the U.S. Environmental Protection Agency (EPA), is of great interest due to its health and economical effects. However, O3 contributions from different emission sources are not well understood due to its complicated nonlinear reactions. In this study, O3 source apportionment methods and the applications are firstly reviewed to provide a comprehensive understanding for O3 formations. Application of High-order Decoupled Direct Method (HDDM), brute force method (BFM), O3 source apportionment technology (OSAT) and source-oriented method in O3 simulations are discussed in detail. And applications of different O3 regime schemes are compared with each other. Improved three regime scheme (3R) has better performance in tracking O3 contributions from its precursors. Then, the Community Multi-scale Air Quality (CMAQ) model is applied to predict O3 concentrations in NCP with meteorological conditions generated by the Weather Research and Forecasting (WRF) model. Model performance from using anthropogenic emissions from the updated Emissions Database for Global Atmospheric Research (EDGAR+) and the Multi-resolution Emission Inventory for China (MEIC) are validated. The statistical analysis reveals a better performance from EDGAR+. The source-oriented simulation with 3R technique indicates that NOx emissions dominate in most regions while contributions from VOCs are higher in megacities than in other regions in NCP. Industry, on-road and energy emissions are major sources, which account for ~75% of total emission-related O3 formation. Emissions from local and surrounding regions are the main O3 contributors and emissions from central China and YRD have strong impacts in peak episodes. O3 simulation and source apportionment in SUS reveal that NOx emissions from on-road, energy dominate the emission-related O3 while VOCs emissions have less contribution except those from biogenic sectors. Health risk analysis indicates that more than 0.11 million premature mortalities are associated with O3 level in NCP due to respiratory (0.04-0.05 million) and cardiovascular (0.07-0.06 million) diseases. A total of 0.03 all-cause premature mortality is estimated for SUS with ~4.6 and ~7.9 thousand from respiratory and cardiovascular diseases, respectively
Plasma exosomes from children with juvenile dermatomyositis are taken up by human aortic endothelial cells and are associated with altered gene expression in those cells
BACKGROUND:
The pathology of juvenile dermatomyositis (JDM) is characterized by prominent vessel wall and perivascular inflammation. This feature of the disease has remained unexplained and under-investigated. We have hypothesized that plasma exosomes, which play an important role in inter-cellular communication, may play a role in the vascular injury associated with JDM.
OBJECTIVE:
To characterize the circulating exosomes of children with JDM and determine whether the small RNA cargoes within those exosomes are capable of altering transcriptional programs within endothelial cells.
DESIGN/METHODS:
We purified exosomes from plasma samples of children with active, untreated JDM (n = 6) and healthy controls (n = 9). We characterized the small RNA cargoes in JDM and control exosomes by RNA sequencing using the Illumina HiSeq 2500 platform. We then incubated isolated exosomes from healthy controls and children with JDM with cultured human aortic endothelial cells (HAEC) for 24 h. Fluorescence microscopy was used to confirm that both control and JDM exosomes were taken up by HAEC. RNA was then purified from HAEC that had been incubated with either control or JDM exosomes and sequenced on the Illumina platform. Differential expression of mRNAs from HAEC incubated with control or JDM exosomes was ascertained using standard computational methods. Finally, we assessed the degree to which differential gene expression in HAEC could be attributed to the different small RNA cargoes in JDM vs control exosomes using conventional and novel analytic methods.
RESULTS:
We identified 10 small RNA molecules that showed differential abundance when we compared JDM and healthy control exosomes. Fluorescence microscopy of labeled exosomes confirmed that both JDM and control exosomes were taken up by HAEC. Differential gene expression analysis revealed 59 genes that showed differential expression between HAEC incubated with JDM exosomes vs HAEC incubated with exosomes from controls. Statistical analysis of gene expression data demonstrated that multiple miRNAs exerted transcriptional control on multiple genes with HAEC.
CONCLUSIONS:
Plasma exosomes from children with active, untreated JDM are taken up by HAEC and are associated with alterations in gene expression in those cells. These findings provide new insight into potential mechanisms leading to the targeting of vascular tissue by the immune system in JDM
Adaptive Tracking Control of Second-Order Multiagent Systems with Jointly Connected Topologies
This paper considers a consensus problem of leader-following multiagent system with unknown dynamics and jointly connected topologies. The multiagent system includes a self-active leader with an unknown acceleration and a group of autonomous followers with unknown time-varying disturbances; the network topology associated with the multiagent system is time varying and not strongly connected during each time interval. By using linearly parameterized models to describe the unknown dynamics of the leader and all followers, we propose a decentralized adaptive tracking control protocol by using only the relative position measurements and analyze the stability of the tracking error and convergence of the adaptive parameter estimators with the help of Lyapunov theory. Finally, some simulation results are presented to demonstrate the proposed adaptive tracking control
Soluble inflammatory mediators induce transcriptional re-organization that is independent of dna methylation changes in cultured human chorionic villous trophoblasts.
The studies proposed here were undertaken to test the hypothesis that, under specific circumstances (e.g., a strong enough inflammatory stimulus), genes that are repressed at the maternal-fetal interface via DNA methylation might be de-methylated, allowing either a maternal immune response to the semi-allogenic fetus or the onset of early labor. Chorionic trophoblasts (CT) were isolated from fetal membranes, followed by incubation with medium from LPS-activated PBMC or resting PBMC medium for 2 h. RNA and DNA were isolated from the cells for RNA-seq and DNA methylation studies. Two hrs after being exposed to conditioned medium from LPS-activated PBMC, CT showed differential expression of 114 genes, all but 2 of which showed higher expression in the stimulated cells than is the unstimulated cells. We also identified 318 differentially methylated regions (DMRs) that associated with 306 genes (155 protein coding genes) in the two groups, but the observed methylation changes had negligible impact on the observed transcriptional changes in CT. CT display complex patterns of transcription in response to inflammation. DNA methylation does not appear to be an important regulator of the observed transcriptional changes
Consensus of Fractional-Order Multiagent Systems with Nonuniform Time Delays
Due to the complex external environment, many multiagent systems cannot be precisely described or even cannot be described by an integer-order dynamical model and can only be described by a fractional-order dynamical model. In this paper, consensus problems are investigated for two types of fractional-order multiagent systems (FOMASs) with nonuniform time delays: FOMAS with symmetric time delays and undirected topology and FOMAS with asymmetric time delays and directed topology. Employing the Laplace transform and the frequency-domain theory, two delay margins are obtained to guarantee the consensus for the two types of FOMAS, respectively. These results are also suitable for the integer-order dynamical model. Finally, simulation results are provided to illustrate the effectiveness of our theoretical results
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