Emission characteristics of CO, NOx, SO2 and indications of biomass burning observed at a rural site in eastern China

Atmospheric O3, CO, SO2, and NO* y (NO* y ≈ NO + NO2 + PAN + organic nitrates + HNO3 + N2O5 + ⋯) were measured in 1999-2000 at a rural/agricultural site in the Yangtze Delta of China. In this paper we analyze the measurement results to show the emission characteristics of the measured gases and to infer relevant emission ratios. Positive correlations were found between CO and NO* y with a slope (Δ[CO]/Δ[NO* y]) of 36 (ppbv/ppbv) for the winter and nighttime measurements. The ratio is considerably larger than that (≈10 ppbv/ppbv) observed in the industrialized countries. The highest CO/NO* y ratio (30-40 ppbv/ppbv) occurred in September-December 1999 and June 2000. The good correlation between CO and the biomass burning tracer CH3Cl and the lack of correlation with the industrial tracer C2Cl4 suggests that the burning of biofuels and crop residues is a major source for the elevated CO and possibly for other trace gases as well. The average SO2 to NO* y ratio was 1.37 ppbv/ppbv, resulting from the use of relatively high-sulfur coals in China. The measured SO2/NO* y and ΔCO/ΔNO* y were compared with the respective ratios from the current emission inventories for the study region, which indicated a comparable SO2/NOx emission ratio but a large discrepancy for CO/NOx. The observed CO to NO* y ratio was more than 3 times the emission ratio derived from the inventories, indicating the need for further improvement of emission estimates for the rural/agricultural regions in China. Additional research will be needed to study the implications of rural emissions to atmospheric chemistry and climate on both regional and global scales.Department of Civil and Environmental Engineerin

Source contributions to ambient VOCs and CO at a rural site in eastern China

Ambient data on volatile organic compounds (VOCs) and carbon monoxide (CO) obtained at a rural site in eastern China are analyzed to investigate the nature of emission sources and their relative contributions to ambient concentrations. A principal component analysis (PCA) showed that vehicle emissions and biofuel burning, biomass burning and industrial emissions were the major sources of VOCs and CO at the rural site. The source apportionments were then evaluated using an absolute principal component scores (APCS) technique combined with multiple linear regressions. The results indicated that 71%±5% (average±standard error) of the total VOC emissions were attributed to a combination of vehicle emissions and biofuel burning, and 7%±3% to gasoline evaporation and solvent emissions. Both biomass burning and industrial emissions contributed to 11%±1% and 11%±0.03% of the total VOC emissions, respectively. In addition, vehicle emissions and biomass and biofuel burning accounted for 96%±6% of the total CO emissions at the rural site, of which the biomass burning was responsible for 18%±3%. The results based on PCA/APCS are generally consistent with those from the emission inventory, although a larger relative contribution to CO from biomass burning is indicated from our analysis. © 2004 Elsevier Ltd. All rights reserved

Single-mode plastic optical fibers

2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Relationships of trace gases and aerosols and the emission characteristics at Lin'an, a rural site in eastern China, during spring 2001

We present measurements of trace gases and fine aerosols obtained from a rural site in eastern China during 18 February to 30 April 2001. The field program aimed to characterize the variations in aerosol and gaseous pollutant concentrations and the emission signatures from the inland region of eastern China in the spring season. The data included O3, CO, NO, NOy*, SO2, methane, C2-C8 nonmethane hydrocarbons (NMHCs), C 1-C2 halocarbons, and the chemical composition of PM2.5. The average hourly mixing ratios (±standard deviation) of CO, SO2, and NOy* were 677 (±315) ppbv, 15.9 (±14.6) ppbv, and 13.8 (±7.2) ppbv, respectively. The mean daytime ozone mixing ratio was 41 (± 19) ppbv. The most abundant NMHC was ethane (3189 ± 717 pptv), followed by ethyne (2475 ± 1395 pptv), ethene (1679 ± 1455 pptv), and toluene (1529 ± 1608 pptv). Methyl chloride was the most abundant halocarbon (1108 ± 653 pptv). The average concentrations of particulate organic matter (POM, as organic carbon, OC, times 1.4) and elemental carbon (EC) in PM2.5 were 21.5 (±7) μg/m3 and 2.5 (±0.7) μg/m3, respectively, and sulfate and nitrate levels were 17.3 (±6.6) and 6.5 (±4) μg/m3, respectively. CO showed moderate to good correlation with NOy* (r2 = 0.59), OC (r2 = 0.65), CH3Cl (r2 = 0.59), soluble potassium (r2 = 0.53), and many NMHCs, indicating contributions from the burning of biofuel/biomass. CO also correlated with an industrial tracer, C2Cl4, indicative of some influence from industrial sources. SO2, on the other hand, correlated well with EC (r2 = 0.56), reflecting the contribution from the burning of coal. Ammonium was sufficiently abundant to fully neutralize sulfate and nitrate, indicating that there were strong emissions of ammonia from agricultural activities. Silicon and calcium had poor correlations with iron and aluminum, revealing the presence of source(s) for Si and Ca other than from soil. Examination of C2H2/CO, C3H8/C 2H6, nitrate/(nitrate + NOy* , and sulfate/(SO2 + sulfate) suggested that relatively fresh air masses had been sampled at the study site in the spring season. Comparison of the observed ratios/slopes with those derived from emission inventories showed that while the observed SO2/NO y* ratio (1.29 ppbv/ppbv) in March was comparable (within 20%) to the inventory-derived ratio for the study region, the measured CO/NOy* slope (37 ppbv/ppbv) was about 200% larger. The observed slope of CO relative to NMHC (including ethane, propane, butanes, ethene, and ethyne) also indicated the presence of excess CO, compared to the ratios from the inventories. These results strongly suggest that emissions of CO in eastern China have been underrepresented. The findings of this study highlight the importance of characterizing trace gases and aerosols within source regions of the Asian continent. The springtime results were also compared with data previously collected at the site in 1999-2000 and with those obtained on the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft and from a coastal site in South China for the same study period. Copyright 2004 by the American Geophysical Union

The Reliability and Effectiveness of FBGS in Textile Composite

2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Assessing impacts of climate change and human activities on streamflow and sediment discharge in the Ganjiang River basin (1964-2013)

© 2019 by the authors. National large-scale soil and water conservation controls on the Gangjiang River basin have been documented, but the effect of governance on regional watershed hydrology and how the main driving factors act have not been systematically studied yet. To do this, this study evaluated changing trends and detected transition years for both streamflow and sediment discharge using long-term historical records at seven hydrological stations in the Ganjiang River basin over the past 50 years. The double mass curve (DMC) method was used to quantify the effects of both climate change and human activities on hydrological regime shifts. The results showed that the distributions of precipitation, streamflow, and sediment discharge within a year are extremely uneven and mainly concentrated in the flood season of Jiangxi Province. None of the stations showed significant trends over time for either annual precipitation or streamflow, while the annual sediment discharge at most stations decreased significantly over time. The estimation of sediment discharge via DMC indicated that after the transition years, there were rapid reductions in sediment discharge at all hydrological stations, and the average decline degree of midstream and downstream were much larger than that of upstream. Human activities, especially the increase of vegetation cover and construction of large and medium-sized reservoirs, provided a significantly greater contribution to the reduction of sediment discharge than did precipitation changes. As a case study of river evolution under global change environment, this study could provide scientific basis for the control of soil erosion and the management of water resources in Ganjiang River, as well as for the related research of Poyang Lake and the Yangtze River basin of China

Potential immunomodulatory effects of SCAP on Treg conversion in tissue regeneration for regenerative endodontic treatment

To evaluate the expression of Foxp3‐positive lymphocytes around newly formed tissue after regenerative endodontic treatment (RET) in vivo and investigate the effects of stem cells from the apical papilla (SCAP) on the conversion of CD4+CD25− T cells to CD4+CD25+Foxp3+ regulatory T cells (Tregs) in vitro. Methodology Three 6‐month‐old beagles with nine doubled‐rooted premolars in each dog were randomly assigned to the RET group and the control group. RET was performed after apical periodontitis had been induced in the experimental immature teeth. Three months later, the expression of Foxp3 was detected in the histological sections by immunofluorescent staining. Human SCAP and CD4+CD25− T cells from mice spleens (1 : 1 and 1 : 5) were co‐cultured in cell–cell contact or in Transwells, respectively, for 24 and 72 h in vitro. The percentage of Tregs was evaluated by flow cytometry. The results were analysed using the Fisher's exact test and analysis of variance. P < 0.05 was regarded as statistically significant. Results Inflammatory cells were present with tissue regeneration in the RET group, and Foxp3‐positive T cells were enriched around the newly formed tissues. SCAP promoted Treg conversion after 72 h in vitro. Cell–cell contact played an important role after the 24 h co‐culture, whilst soluble factors were also involved after 72 h (P < 0.05). Conclusions SCAP promoted the conversion of pro‐inflammatory T cells to Tregs in vitro. Tregs were enriched around the regenerating tissues in the root canals after RET, which may create a suitable immune microenvironment for the differentiation of SCAP. This study provides an underlying mechanism for tissue regeneration during RET

The Interaction between the First Transmembrane Domain and the Thumb of ASIC1a Is Critical for Its N-Glycosylation and Trafficking

Acid-sensing ion channel-1a (ASIC1a), the primary proton receptor in the brain, contributes to multiple diseases including stroke, epilepsy and multiple sclerosis. Thus, a better understanding of its biogenesis will provide important insights into the regulation of ASIC1a in diseases. Interestingly, ASIC1a contains a large, yet well organized ectodomain, which suggests the hypothesis that correct formation of domain-domain interactions at the extracellular side is a key regulatory step for ASIC1a maturation and trafficking. We tested this hypothesis here by focusing on the interaction between the first transmembrane domain (TM1) and the thumb of ASIC1a, an interaction known to be critical in channel gating. We mutated Tyr71 and Trp287, two key residues involved in the TM1-thumb interaction in mouse ASIC1a, and found that both Y71G and W287G decreased synaptic targeting and surface expression of ASIC1a. These defects were likely due to altered folding; both mutants showed increased resistance to tryptic cleavage, suggesting a change in conformation. Moreover, both mutants lacked the maturation of N-linked glycans through mid to late Golgi. These data suggest that disrupting the interaction between TM1 and thumb alters ASIC1a folding, impedes its glycosylation and reduces its trafficking. Moreover, reducing the culture temperature, an approach commonly used to facilitate protein folding, increased ASIC1a glycosylation, surface expression, current density and slowed the rate of desensitization. These results suggest that correct folding of extracellular ectodomain plays a critical role in ASIC1a biogenesis and function

miR-27b Targets KSRP to Coordinate TLR4-Mediated Epithelial Defense against Cryptosporidium parvum Infection

Cryptosporidium is a protozoan parasite that infects the gastrointestinal epithelium and causes a diarrheal disease. Toll-like receptor (TLR)- and NF-κB-mediated immune responses from epithelial cells, such as production of antimicrobial peptides and generation of reactive nitrogen species, are important components of the host's defense against cryptosporidial infection. Here we report data demonstrating a role for miR-27b in the regulation of TLR4/NF-κB-mediated epithelial anti-Cryptosporidium parvum responses. We found that C. parvum infection induced nitric oxide (NO) production in host epithelial cells in a TLR4/NF-κB-dependent manner, with the involvement of the stabilization of inducible NO synthase (iNOS) mRNA. C. parvum infection of epithelial cells activated NF-κB signaling to increase transcription of the miR-27b gene. Meanwhile, downregulation of KH-type splicing regulatory protein (KSRP) was detected in epithelial cells following C. parvum infection. Importantly, miR-27b targeted the 3′-untranslated region of KSRP, resulting in translational suppression. C. parvum infection decreased KSRP expression through upregulating miR-27b. Functional manipulation of KSRP or miR-27b caused reciprocal alterations in iNOS mRNA stability in infected cells. Forced expression of KSRP and inhibition of miR-27b resulted in an increased burden of C. parvum infection. Downregulation of KSRP through upregulating miR-27b was also detected in epithelial cells following LPS stimulation. These data suggest that miR-27b targets KSRP and modulates iNOS mRNA stability following C. parvum infection, a process that may be relevant to the regulation of epithelial anti-microbial defense in general