Evolution of Ozone Formation Sensitivity during a Persistent Regional Ozone Episode in Northeastern China and Its Implication for a Control Strategy.

In recent years, the magnitude and frequency of regional ozone (O3) episodes have increased in China. We combined ground-based measurements, observation-based model (OBM), and the Weather Research and Forecasting and Community Multiscale Air Quality (WRF-CMAQ) model to analyze a typical persistent O3 episode that occurred across 88 cities in northeastern China during June 19-30, 2021. The meteorological conditions, particularly the wind convergence centers, played crucial roles in the evolution of O3 pollution. Daily analysis of the O3 formation sensitivity showed that O3 formation was in the volatile organic compound (VOC)-limited or transitional regime at the onset of the pollution episode in 92% of the cities. Conversely, it tended to be or eventually became a NOx-limited regime as the episode progressed in the most polluted cities. Based on the emission-reduction scenario simulations, mitigation of the regional O3 pollution was found to be most effective through a phased control strategy, namely, reduction of a high ratio of VOCs to NOx at the onset of the pollution and lower ratio during evolution of the O3 episode. This study presents a new possibility for regional O3 pollution abatement in China based on a reasonable combination of OBM and the WRF-CMAQ model.

Air quality and health co-benefits of China's carbon dioxide emissions peaking before 2030.

Recent evidence shows that carbon emissions in China are likely to peak ahead of 2030. However, the social and economic impacts of such an early carbon peak have rarely been assessed. Here we focus on the economic costs and health benefits of different carbon mitigation pathways, considering both possible socio-economic futures and varying ambitions of climate policies. We find that an early peak before 2030 in line with the 1.5 °C target could avoid ~118,000 and ~614,000 PM2.5 attributable deaths under the Shared Socioeconomic Pathway 1, in 2030 and 2050, respectively. Under the 2 °C target, carbon mitigation costs could be more than offset by health co-benefits in 2050, bringing a net benefit of $393-$3,017 billion (in 2017 USD value). This study not only provides insight into potential health benefits of an early peak in China, but also suggests that similar benefits may result from more ambitious climate targets in other countries.

The effect of urban morphological characteristics on the spatial variation of PM2.5 air quality in downtown Nanjing.

The effects of the urban morphological characteristics on the spatial variation of near-surface PM2.5 air quality were examined. Unlike previous studies, we performed the analyses in real urban environments using continuous observations covering the whole scale of urban densities typically found in cities. We included data from 31 measurement stations divided into 8 different wind sectors with individually defined morphological characteristics leading to highly varying urban characteristics. The urban morphological characteristics explained up to 73% of the variance in normalized PM2.5 concentrations in street canyons, indicating that the spatial variation of the near-surface PM2.5 air quality was mostly defined by the characteristics studied. The fraction of urban trees nearby the stations was found to be the most important urban morphological characteristic in explaining the PM2.5 air quality, followed by the height-normalized roughness length as the second important parameter. An increase in the fraction of trees within 50 m of the stations from 25 percentile to 75 percentile (i.e. by the interquartile range, IQR) increased the normalized PM2.5 concentration by up to 24% in the street canyons. In open areas, an increase in the trees by the IQR actually decreased the normalized PM2.5 by 6% during the pre-COVID period. An increase in the height-normalized roughness length by the IQR increased the normalized PM2.5 by 9% in the street canyons. The results obtained in this study can help urban planners to identify the key urban characteristics affecting the near-surface PM2.5 air quality and also help researchers to evaluate how representative the existing measurement stations are compared to other parts of the cities.

Aerosol-boundary-layer-monsoon interactions amplify semi-direct effect of biomass smoke on low cloud formation in Southeast Asia.

Low clouds play a key role in the Earth-atmosphere energy balance and influence agricultural production and solar-power generation. Smoke aloft has been found to enhance marine stratocumulus through aerosol-cloud interactions, but its role in regions with strong human activities and complex monsoon circulation remains unclear. Here we show that biomass burning aerosols aloft strongly increase the low cloud coverage over both land and ocean in subtropical southeastern Asia. The degree of this enhancement and its spatial extent are comparable to that in the Southeast Atlantic, even though the total biomass burning emissions in Southeast Asia are only one-fifth of those in Southern Africa. We find that a synergetic effect of aerosol-cloud-boundary layer interaction with the monsoon is the main reason for the strong semi-direct effect and enhanced low cloud formation in southeastern Asia.

ENSO and Southeast Asian biomass burning modulate subtropical trans-Pacific ozone transport.

Trans-Pacific transport of enhanced ozone plumes has been mainly attributed to fossil fuel combustion in Asia in spring, but less attention has been paid to vegetation fires in Asia. Here we show that the El Niño-Southern Oscillation (ENSO)-modulated fires in Southeast Asia, rather than Asian fossil fuel plumes, dominate the interannual variability of springtime trans-Pacific transport of ozone across the entire North Pacific Ocean. During El Niño springs, the intensified fires from both the Indochinese Peninsula and Indonesia, together with large-scale circulation anomalies, result in enhanced ozone plumes that stretch over 15 000 km in both the lower-middle and upper troposphere. This enhancement is also observed in the in situ measurements of ozone concentration, with an almost 10% increase at Mauna Loa Observatory, Hawaii, a unique site to monitor the long-distance transport over the North Pacific. This study reports an unexpectedly strong influence of vegetation fires, linked with climate variability, on global tropospheric chemistry and proves once more how complex the interactions in the climate system are.

Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China.

To control the spread of the 2019 novel coronavirus (COVID-19), China imposed nationwide restrictions on the movement of its population (lockdown) after the Chinese New Year of 2020, leading to large reductions in economic activities and associated emissions. Despite such large decreases in primary pollution, there were nonetheless several periods of heavy haze pollution in eastern China, raising questions about the well-established relationship between human activities and air quality. Here, using comprehensive measurements and modeling, we show that the haze during the COVID lockdown was driven by enhancements of secondary pollution. In particular, large decreases in NOx emissions from transportation increased ozone and nighttime NO3 radical formation, and these increases in atmospheric oxidizing capacity in turn facilitated the formation of secondary particulate matter. Our results, afforded by the tragic natural experiment of the COVID-19 pandemic, indicate that haze mitigation depends upon a coordinated and balanced strategy for controlling multiple pollutants.

Nonlinear response of nitrate to NOx reduction in China during the COVID-19 pandemic.

In recent years, nitrate plays an increasingly important role in haze pollution and strict emission control seems ineffective in reducing nitrate pollution in China. In this study, observations of gaseous and particulate pollutants during the COVID-19 lockdown, as well as numerical modelling were integrated to explore the underlying causes of the nonlinear response of nitrate mitigation to nitric oxides (NOx) reduction. We found that, due to less NOx titration effect and the transition of ozone (O3) formation regime caused by NOx emissions reduction, a significant increase of O3 (by ∼ 69%) was observed during the lockdown period, leading to higher atmospheric oxidizing capacity and facilitating the conversion from NOx to oxidation products like nitric acid (HNO3). It is proven by the fact that 26-61% reduction of NOx emissions only lowered surface HNO3 by 2-3% in Hebi and Nanjing, eastern China. In addition, ammonia concentration in Hebi and Nanjing increased by 10% and 40% during the lockdown, respectively. Model results suggested that the increasing ammonia can promote the gas-particle partition and thus enhance the nitrate formation by up to 20%. The enhanced atmospheric oxidizing capacity together with increasing ammonia availability jointly promotes the nitrate formation, thereby partly offsetting the drop of NOx. This work sheds more lights on the side effects of a sharp NOx reduction and highlights the importance of a coordinated control strategy.

A PCR assay with high sensitivity and specificity for the detection of swine toxoplasmosis based on the GRA14 gene.

Toxoplasma gondii, an intracellular apicomplexan protozoan parasite, can infect all warm-blooded animals. Infected swine are considered one of the most important sources of T. gondii infection in humans. Rapidly and effectively diagnosing T. gondii infection in swine is essential. PCR-based diagnostic tests have been fully developed, and very sensitive and specific PCR is crucial for the diagnosis of swine toxoplasmosis. In this study, we used the T. gondii dense granule protein 14 (GRA14) gene as a target to design specific primers and established a high-specificity and high-sensitivity PCR detection method for swine toxoplasmosis. Notably, this PCR method could detect T. gondii tachyzoite DNA in the acute infection phase. The GRA14 gene PCR assay detected a minimum of 2.35 tachyzoites of T. gondii and can be used for T. gondii detection in blood, tissue, semen, urine and waste feed specimens. A total of 5462 blood specimens collected from pigs in 5 provinces and autonomous regions in southern China during 2016-2017 were assessed by the newly established GRA14 gene PCR method. The overall T. gondii infection rate was 18.9 % (1033/5462). According to the statistical analysis of different regions in China, the positive rates of swine toxoplasmosis from 2016 to 2017 were highest in the Shaanxi, Fujian and Guangdong areas, at 31.7 % (44/139), 21.9 % (86/391) and 18.8 % (874/4645), respectively. Specimens collected in 2017 had a higher positive rate (19.1 %) than those collected in 2016 (16.1 %). In addition, specimens collected in autumn (39.4 %), spring (22.8 %) and winter (18.2 %) had higher positive rates than those collected in summer (3.8 %). These results indicate that the new PCR method based on the T. gondii GRA14 gene has utility for the diagnosis of swine toxoplasmosis and can facilitate the diagnosis of toxoplasmosis in clinical laboratories.

Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China.

Despite the large reduction in anthropogenic activities due to the outbreak of COVID-19, air quality in China has witnessed little improvement and featured great regional disparities. Here, by combining observational data and simulations, this work aims to understand the diverse air quality response in two city clusters, Yangtze River Delta region (YRD) and Pearl River Delta region (PRD), China. Though there was a noticeable drop in primary pollutants in both the regions, differently, the maximum daily 8 h average ozone (O3) soared by 20.6-76.8% in YRD but decreased by 15.5-28.1% in PRD. In YRD, nitrogen oxide (NOx) reductions enhanced O3 accumulation and hence increased secondary aerosol formation. Such an increment in secondary organic and inorganic aerosols under stationary weather reached up to 36.4 and 10.2%, respectively, which was further intensified by regional transport. PRD was quite the opposite. The emission reductions benefited PRD air quality, while regional transport corresponded to an increase of 17.3 and 9.3% in secondary organic and inorganic aerosols, respectively. Apart from meteorology, the discrepancy in O3-VOCs-NOx relationships determined the different O3 responses, indicating that future emission control shall be regionally specific, instead of one-size-fits-all cut. Overall, the importance of regionally coordinated and balanced control strategy for multiple pollutants is highly emphasized.

Weakened Aerosol-PBL Interaction During COVID-19 Lockdown in Northern China.

Anthropogenic emissions were greatly constrained during COVID-19 lockdown in China. Nevertheless, observations still showed high loadings of fine particles (PM2.5) over northern China with secondary aerosols increasing by 15 µg/m3 yet a ∼10% drop in light-absorbing black carbon (BC). Such a chemical transition in aerosol composition tended to make the atmosphere more scattering, indicated by satellite-retrieved aerosol absorption optical depth falling by 60%. Comparison between weather forecast and radiosonde observations illustrated that, without upper-level heating induced by BC, the stabilized stratification diminished, which was conducive for planetary boundary layer (PBL) mixing and thus near-surface pollution dispersion. Furthermore, coupled dynamic-chemistry simulations estimated that emission reduction during the lockdown weakened aerosol-PBL interaction and thus a reduction of 25 µg/m3 (∼50%) in PM2.5 enhancement. Based on the unique natural experiment, this work observationally confirmed and numerically quantified the importance of BC-induced meteorological feedback, further highlighting the priority of BC control in haze mitigation.

Pneumatic Lithotripsy versus Holmium Laser Lithotripsy in Percutaneous Nephrolithotomy for Patients with Guy's Stone Score Grade IV Kidney Stone.

BACKGROUND AND OBJECTIVE: The aim of this study was to compare the efficacy and reliability of holmium (Ho:YAG) laser lithotripsy (HLL) and pneumatic lithotripsy (PL) in percutaneous nephrolithotomy (PCNL) in the treatment of patients with Grade IV kidney stones based on Guy's Stone Score. STUDY DESIGN/MATERIALS AND METHODS: This retrospective study included 103 patients with Grade IV kidney stones out of 440 patients who underwent PCNL through HLL and PL in Second Affiliated Hospital of Shantou University Medical College, China, from January 2016 to December 2018. We analyzed preoperative, intraoperative, and postoperative variables of the patients to evaluate the efficacy and reliability of PCNL procedures. RESULTS: Patients were categorized as Grade I, II, III, and IV, and the patients of each grade were 85 (19.32%), 39 (8.86%), 213 (48.41%), and 103 (23.41%), respectively. In Grade IV, the total operative time (min) for the PL and HLL groups was 137.7 ± 47.79 and 134.27 ± 53.38, respectively (p = 0.744). The variation in laboratory examination values including ΔHGB (g/L), ΔHCT, ΔPCT, and ΔCr (µmol/L) for PL and HLL groups was 19 ± 11.23/12 ± 15.42 (p = 0.012), 0.057 ± 0.034/0.038 ± 0.045 (0.009), 0.027 ± 0.034/0.026 ± 0.034 (0.702), and 3.07 ± 17.4/20.54 ± 65.93 (0.692), respectively. The postoperative hospitalization day was 8.94 ± 4.2 and 7.73 ± 2.75 (p = 0.015), respectively. As for the stone-free rate (SFR), the SFRs for PL and HLL were 48.15% (n = 39/81) and 59.09% (n = 13/22) (p = 0.363), respectively. CONCLUSIONS: HLL showed a comparable advantage of not only decreased postoperative hemoglobin and hematocrit but also fewer postoperative hospitalization days. Based on the results of our retrospective study, for those Grade IV kidney stone patients who have a risk of bleeding before PCNL operation, HLL can be a considerable treatment option. Besides, in consideration of reducing human care cost, HLL which showed fewer hospitalization days, would be more welcome by patients.

Secondary aerosol formation and its linkage with synoptic conditions during winter haze pollution over eastern China.

Eastern China has been facing severe winter haze pollution due mainly to secondary aerosol. Existing studies have suggested that stagnant weather or fast chemical production led to frequent haze in this region. However, few works focus on the linkage between secondary production of sulfate, nitrate, and ammonium (SNA) and synoptic conditions, and their joint contribution to PM2.5. In this study, by combining in-situ measurements on meteorology and aerosol chemical composition at three main cities together with a regional model with improved diagnose scheme, we investigated the chemical formation and accumulation of main secondary composition, i.e. SNA under typical synoptic conditions. It is indicated that SNA did play a vital role in haze pollution across eastern China, contributing more than 40% to PM2.5 mass concentration. As most fast developing region, the Yangtze River Delta (YRD) was slightly polluted during stable weather with local chemical production accounting for 61% SNA pollution. While under the influence of cold front, the pollution was aggravated and advection transport became the predominant contributive process (85%). Nevertheless, the chemical production of SNA was notably enhanced due to the uplift of air pollutant and elevated humidity ahead of the cold front, which then facilitated the heterogeneous and aqueous-phase oxidation of precursors. We also found the substantial difference in the phase equilibrium of nitrate over the land surface and ocean due to changes in temperature, ammonia availability and dry deposition. This study highlights the close link between synoptic weather and chemical production, and the resultant vertical and spatial heterogeneity of pollution.

Identification of Goose PKR Gene: Structure, Expression Profiling, and Antiviral Activity Against Newcastle Disease Virus.

Double-stranded RNA-dependent protein kinase (PKR) is an important antiviral IFN-stimulated gene (ISGs) that recognizes double-stranded RNA (dsRNA) and mediates inhibition of translation initiation and protein synthesis in various types of viral infection. In this study, the complete coding sequence (CDS) of goose PKR (goPKR) is identified and characterized. The open reading frame (ORF) of goPKR is 1668 bp, which encodes a polypeptide of 555 amino acids. The sequence identity results demonstrate that the goose PKR is most closely related to duck PKR gene, with nucleotide identities of 91.6%, whereas nucleotide identity of the goose PKR to chicken, human, and mouse PKR is 76.4%, 51.9%, and 52.0%, respectively. Interestingly, the deduced amino acid sequence of goose PKR contains 3 main structure domains, including 2 double-strand RNA-binding motif (dsRBM) domains and one serine/threonine protein kinase domain. This is similar to the chicken and mammals, whereas it is different from duck PKR protein, which contains only one dsRBM1 domain and one serine/threonine protein kinase domain. Quantitative real-time PCR analysis indicates that goose PKR mRNA is widely expressed in all sampled tissues. It is highly expressed in the blood, spleen, lung, and bursa of Fabricius and jejunum and is slightly expressed in heart, muscle, trachea, and brain. The results of confocal microscopy suggest that PKR-EGFP is mainly localized in the cytoplasm, and overexpression of goPKR protein significantly reduces Newcastle disease virus (NDV) replication (viral copies and viral titer) in goose embryo fibroblasts. These findings show that goose PKR is an important antiviral ISG, involved in the antiviral innate immune defense to NDV in geese.

Generalized nonlinear weakly singular retarded integral inequalities with maxima and their applications.

This paper deals with a generalized nonlinear weakly singular retarded Wendroff-type integral inequality with maxima of an unknown function of two variables. The key is that a technique of monotonization without separability and monotonicity of given functions is used for estimating the boundedness of unknown functions. Then our outcomes can be helpful to weaken conditions for some known results. By applying our results, the uniqueness of solutions for some singular integral equation with maxima may be proven.

[Gossypol decreases the expression of connexin 43 in Sertoli cells].

OBJECTIVE: To study the effect of gossypol on the expression of connexin 43 (CX43) in Sertoli cells. METHODS: TM4 Sertoli cells were cultured and treated with gossypol at the concentrations of 1.25, 2.5, 5 and 10 micromol/L for 6, 12, 24 and 48 hours. The cytotoxicity of gossypol was assessed by CCK-8 assay, and the expression of CX43 in the normal TM4 Sertoli cells and in those treated with different concentrations of gossypol for different times was detected by RT-PCR and immunofluorescence analysis. RESULTS: Semiquantitative RT-PCR and immunofluorescence analysis showed the expression of CX43 in the normal TM4 cells. At 24 hours of exposure to gossypol, the expression began to decrease gradually with the prolonging of time and the increasing concentration of gossypol (P < 0.05). CONCLUSION: Gossypol reduces the expression of CX43 in TM4 Sertoli cells, which might underlie the mechanism of its antifertility action.

Developmental expression pattern of a novel gene, TSG23/Tsg23, suggests a role in spermatogenesis.

A novel gene, TSG23/Tsg23, was identified by comparing the expression profiles of human adult and fetal testis using Affymetrix Genechips. RT-PCR analysis from multiple human and mouse tissues indicated TSG23/Tsg23 mRNA was mainly expressed in the testis. In situ hybridization revealed that TSG23/Tsg23 mRNA was located in spermatocytes and round spermatids of the seminiferous tubules in human and mouse testis. To further confirm the result from RT-PCR, the antibody for human TSG23 was generated against the protein encoded by the gene. Western blot analysis demonstrated that TSG23 was mainly expressed in human testis, with a molecular weight of about 23 kDa. Immunohistochemistry showed that TSG23 was predominantly located in spermatocytes and round spermatids, consistent with the results from in situ hybridization. In order to explore the function of TSG23 in spermatogenesis, the study compared the expression of TSG23 in the testis from fertile persons and from patients with azoospermia. The results showed that there was less expression in patients with obstructive azoospermia compared with fertile persons, and no detectable TSG23 at mRNA and protein levels in patients with non-obstructive azoospermia. The expression of Tsg23 mRNA was considerably decreased in a time-dependent manner in the testis of an azoospermic mouse model induced by Busulfan. These data suggest that TSG23/Tsg23 is involved in human and mouse spermatogenesis.

Gap junctional protein connexin 43 in rat detrusor muscle with unstable bladder.

BACKGROUND: Unstable bladder is one of the common clinical dysfunctions of the lower urinary tract. Gap junctions (GJs) are the plaques of aqueous channels that facilitate electrical and metabolic communication between the intracellular compartments of adjacent cells, exchange of nutrients and ions between connected cells and transfer of electrical signals. In the present study we investigated the quantitative alterations of the GJ in the rat detrusor muscle and its functional changes related to the developing of unstable bladder (USB). METHODS: Thirteen female Wistar rats (study group) with obstructive unstable bladder as determined by urodynamic study and 10 sham-operated rats (control group) were sacrificed at 6 weeks after surgery. Cystometric investigation, and the content and distribution of the GJ protein connexin 43 (Cx43) in the detrusors which were taken from the bladder of the rats were studied by Western blot and laser confocal microscopy with a double label immunohistochemistry technique. RESULTS: The expression of Cx43 was found adjacent to the detrusor with the laser confocal microscopy. The Cx43 expression increased markedly in the study group (pixel density 29.5 +/- 13.9, staining size (17.9 +/- 8.8) microm2) compared with the control group (pixel density 14.2 +/- 2.2, staining size (5.7 +/- 3.1) microm2, P < 0.05). Western blot analysis demonstrated that Cx43 in the study group (the average gray level was 31.066) was significantly higher than in the control group (the average gray level was 11.701, P < 0.01). CONCLUSION: The increase of GJ leading to a intercellular excitatory communication is one of the important mechanisms related to developing unstable bladder.

Gossypol repressed the gap junctional intercellular communication between Sertoli cells by decreasing the expression of Connexin43.

Previous studies showed that gossypol could block the gap junctional intercellular communication (GJIC) between cultured cells. The present study was designed to investigate the effects of gossypol on the GJIC and the expression of connexin43 (Cx43) in the cultured cells. A Sertoli cell line, TM4, was treated with different concentrations of gossypol 1.25, 2.5, 5, and 10micromol/L for 6, 12, 24, and 48h. Cell viability was assessed with CCK-8 assay. GJIC in the cells was determined using the scrape loading and dye transfer (SLDT) assay; the expression of Cx43 was detected by RT-PCR, immunofluorescence and Western blot analysis. The SLDT assay showed gossypol significantly decreased GJIC between adjacent cells. RT-PCR, immunofluorescence and Western blot analyses demonstrated the expression of Cx43 in TM4 cells. The expression of Cx43 was gradually decreased with the increasing concentrations of gossypol, and the effect occurred as early as 6h after the treatment and continued until 48h. These results suggested that gossypol impaired GJIC by decrease of Cx43 expression in the cells, which is important for Sertoli cells to regulate spermatogenesis.