Mixing states and secondary formation processes of organic nitrogen-containing single particles in Guangzhou, China.

Organic nitrogen (ON) compounds play a significant role in the light absorption of brown carbon and the formation of organic aerosols, however, the mixing state, secondary formation processes, and influencing factors of ON compounds are still unclear. This paper reports on the mixing state of ON-containing particles based on measurements obtained using a high-performance single particle aerosol mass spectrometer in January 2020 in Guangzhou. The ON-containing particles accounted for 21% of the total detected single particles, and the particle count and number fraction of the ON-containing particles were two times higher at night than during the day. The prominent increase in the content of ON-containing particles with the enhancement of NOx mainly occurred at night, and accompanied by high relative humidity and nitrate, which were associated with heterogeneous reactions between organics and gaseous NOx and/or NO3 radical. The synchronous decreases in ON-containing particles and the mass absorption coefficient of water-soluble extracts at 365 nm in the afternoon may be associated with photo-bleaching of the ON species in the particles. In addition, the positive matrix factorization analysis found five factors dominated the formation processes of ON particles, and the nitrate factor (33%) mainly contributed to the production of ON particles at night. The results of this study provide unique insights into the mixing states and secondary formation processes of the ON-containing particles.

Colistin sulfate for decontamination of preservation fluid in kidney transplantation to decrease the incidence of donor-derived infections caused by multidrug-resistant Gram-negative bacteria.

BACKGROUND: Preservation fluid (PF) contamination, especially by multidrug-resistant (MDR) Gram-negative bacteria (GNB), poses a high risk of donor-derived infection (DDI) and severe clinical outcomes. We sought to determine whether the use of colistin sulfate to decontaminate PF in kidney transplantation can decrease the incidence of probable DDI (p-DDI) caused by MDR GNB. METHODS: In a retrospective study of 916 recipients who received deceased donation, 864 PF samples were collected and cultured, and microbiological contaminants were recorded with the recipients' clinical data and outcomes. From March 2016 to May 2019, 624 samples were decontaminated with ceftizoxime, and from June 2019 to March 2021, 240 samples were decontaminated with colistin sulfate. Between-group comparisons were performed to assess the ability of the two decontamination regimens to decrease the incidence of p-DDI, especially MDR GNB-related infection. RESULTS: The overall PF contamination rate was 54.51% (471/864), and 80 samples were positive for MDR GNB contamination. All p-DDIs occurred in the ceftizoxime group (p < 0.001), and 67.65% of p-DDIs were MDR GNB-related. In the ceftizoxime group, 23 of 61 cases of MDR GNB contamination led to related p-DDIs, while none occurred in the colistin sulfate group (p = 0.002). Among the 23 patients with p-DDIs, 5 died due to severe infection, and 2 experienced graft loss. CONCLUSIONS: The goal of decontamination should be to decrease the risk of MDR GNB-related p-DDI, and colistin sulfate could be an effective and feasible option.

Early platelet elevation after complete remission as a prognostic marker of favourable outcomes in favourable- and intermediate-risk acute myeloid leukaemia: A retrospective study.

OBJECTIVES: Platelet (PLT) recovery after chemotherapy is associated with the prognosis of patients with acute myeloid leukaemia (AML). This study aimed to explore the prognostic significance of early high PLT values in patients with de novo non-M3 AML who achieved first complete remission (CR). METHODS: A total of 206 patients with de novo non-M3 AML were analysed in this retrospective study. A receiver operating characteristic (ROC) curve was used to determine the optimal PLT cut-off. The overall survival (OS) and relapse-free survival (RFS) were assessed using Kaplan-Meier and Cox regression analyses. RESULTS: 312×109 /L was confined as the cut-off of the PLT count. The estimated 3-year OS of patients with high PLT was higher than that of their counterparts (72.3% vs. 34.6%, p = 0.001). In subgroup analysis, patients with high PLT had better OS in the favourable- and intermediate-risk (non-adverse-risk) AML (p = 0.001). The estimated 3-year RFS for the high and low PLT groups was 75.1% and 45.7% respectively (p = 0.078). Multivariate analyses revealed that high PLT count was an independent favourable variable for OS (HR = 0.264, p < 0.001) and RFS (HR = 0.375, p = 0.011) in the non-adverse-risk group. CONCLUSION: Our results showed that early high PLT count recovery at first CR in non-adverse-risk AML patients is a positive prognostic marker for survival outcomes.

Inter-comparisons of VOC oxidation mechanisms based on box model: A focus on OH reactivity.

Volatile organic compounds (VOCs) oxidation processes play a very important role in atmospheric chemistry, and the chemical reactions are expressed in various manners in chemical mechanisms. To gain an improved understanding of VOCs evolution during oxidation processes and evaluate the discrepancies of VOCs oxidation schemes among different mechanisms, we used the total VOC reactivity as a diagnostic and evaluated tool to explore the differences for six widely used chemical mechanisms. We compared the total VOC reactivity evolution under high-NOx conditions for several sets of precursors, including n-pentane, toluene, ethene, isoprene and a mixture of 57 Photochemical Assessment Monitoring Stations (PAMS) species in a 0-D photochemical box model. Inter-comparison of total VOC reactivity of individual precursor simulations showed discrepancies to different extent of the oxidation schemes among the studied mechanisms, which are mainly attributed to the different lumping approaches for organic species. The PAMS simulation showed smaller discrepancy than individual precursor cases in terms of total VOC reactivity. SAPRC07 and RACM2 performances are found to better match the MCM for simulation of total VOC reactivity. Evidences suggest that the performance in simulating secondary organic products, OH concentrations and NOx concentrations are related to the OH reactivity discrepancies among various chemical mechanisms. Information in this study can be used in selection of chemical mechanisms to better model OH reactivity in different environments. The results in this study also provide directions to further improve the ability in modelling total VOC reactivity with the chemical mechanisms.

Enhanced mixing state of black carbon with nitrate in single particles during haze periods in Zhengzhou, China.

Black carbon (BC) plays an important role in air quality and climate change, which is closely associated with its mixing state and chemical compositions. In this work the mixing state of BC-containing single particles was investigated to explore the evolution process of ambient BC particles using a single particle aerosol mass spectrometer (SPAMS) in March 2018 in Zhengzhou, China. The BC-containing particles accounted for 61.4% of total detected ambient single particles and were classified into five types including BC-nitrate (BC-N, 52.3%) as the most abundant species, followed by BC-nitrate-sulfate (BC-NS, 22.4%), BCOC (16.8%), BC-fresh (BC-F, 4.5%) and BC-sulfate particles (BC-S, 4.0%). With enhancement of the ambient nitrate concentration, the relative peak area (RPA) of nitrate in BC-N and BCNS particles both increased, yet only the number fraction (Nf) of BCN particles increased while the Nf of BC-NS particles decreased, suggesting that the enhanced mixing state of BC with nitrate was mainly due to the increase in the ambient nitrate mass concentration. In addition, the Nf of BC-N decreased from 65.3% to 28.4% as the absorbing Ångström exponents (AAE) of eBC increased from 0.75 to 1.45, which indicated the reduction of light absorption ability of aged BC particles with the enhanced formation of BC-N particles. The results of this work indicated a change in the mixing state of BC particles due to the dominance of nitrate in PM2.5, which also influenced the optical properties of aged BC particles.

LncRNA lnc-ISG20 promotes renal fibrosis in diabetic nephropathy by inducing AKT phosphorylation through miR-486-5p/NFAT5.

Long non-coding RNA (lncRNA) lnc-ISG20 has been found aberrantly up-regulated in the glomerular in the patients with diabetic nephropathy (DN). We aimed to elucidate the function and regulatory mechanism of lncRNA lnc-ISG20 on DN-induced renal fibrosis. Expression patterns of lnc-ISG20 in kidney tissues of DN patients were determined by RT-qPCR. Mouse models of DN were constructed, while MCs were cultured under normal glucose (NG)/high glucose (HG) conditions. The expression patterns of fibrosis marker proteins collagen IV, fibronectin and TGF-ß1 were measured with Western blot assay. In addition, the relationship among lnc-ISG20, miR-486-5p, NFAT5 and AKT were analysed using dual-luciferase reporter assay and RNA immunoprecipitation. The effect of lnc-ISG20 and miR-486/NFAT5/p-AKT axis on DN-associated renal fibrosis was also verified by means of rescue experiments. The expression levels of lnc-ISG20 were increased in DN patients, DN mouse kidney tissues and HG-treated MCs. Lnc-ISG20 silencing alleviated HG-induced fibrosis in MCs and delayed renal fibrosis in DN mice. Mechanistically, miR-486-5p was found to be a downstream miRNA of lnc-ISG20, while miR-486-5p inhibited the expression of NFAT5 by binding to its 3'UTR. NFAT5 overexpression aggravated HG-induced fibrosis by stimulating AKT phosphorylation. However, NFAT5 silencing reversed the promotion of in vitro and in vivo fibrosis caused by lnc-ISG20 overexpression. Our collective findings indicate that lnc-ISG20 promotes the renal fibrosis process in DN by activating AKT through the miR-486-5p/NFAT5 axis. High-expression levels of lnc-ISG20 may be a useful indicator for DN.

Exosomal microRNA-16-5p from human urine-derived stem cells ameliorates diabetic nephropathy through protection of podocyte.

Diabetic nephropathy (DN) remains one of the severe complications associated with diabetes mellitus. It is worthwhile to uncover the underlying mechanisms of clinical benefits of human urine-derived stem cells (hUSCs) in the treatment of DN. At present, the clinical benefits associated with hUSCs in the treatment of DN remains unclear. Hence, our study aims to investigate protective effect of hUSC exosome along with microRNA-16-5p (miR-16-5p) on podocytes in DN via vascular endothelial growth factor A (VEGFA). Initially, miR-16-5p was predicated to target VEGFA based on data retrieved from several bioinformatics databases. Notably, dual-luciferase report gene assay provided further verification confirming the prediction. Moreover, our results demonstrated that high glucose (HG) stimulation could inhibit miR-16-5p and promote VEGFA in human podocytes (HPDCs). miR-16-5p in hUSCs was transferred through the exosome pathway to HG-treated HPDCs. The viability and apoptosis rate of podocytes after HG treatment together with expression of the related factors were subsequently determined. The results indicated that miR-16-5p secreted by hUSCs could improve podocyte injury induced by HG. In addition, VEGA silencing could also ameliorate HG-induced podocyte injury. Finally, hUSC exosomes containing overexpressed miR-16-5p were injected into diabetic rats via tail vein, followed by qualification of miR-16-5p and observation on the changes of podocytes, which revealed that overexpressed miR-16-5p in hUSCs conferred protective effects on HPDCs in diabetic rats. Taken together, the present study revealed that overexpressed miR-16-5p in hUSC exosomes could protect HPDCs induced by HG and suppress VEGFA expression and podocytic apoptosis, providing fresh insights for novel treatment of DN.

Circ_0000524/miR-500a-5p/CXCL16 axis promotes podocyte apoptosis in membranous nephropathy.

BACKGROUND: Podocytes apoptosis is a hallmark of membranous nephropathy (MN). Circ_0000524 has been reported to be associated with patients with MN, whereas the effect of circ_0000524 on podocytes apoptosis and the underlying mechanisms in MN have not been elaborated. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were performed to detect the expressions of circ_0000524, microRNA-500a-5p (miR-500a-5p), and C-X-C chemokine ligand 16 (CXCL16) in MN tissues and podocytes. Podocyte injury was induced by angiotensin II (AngII). Cell apoptosis was detected by flow cytometry. Caspase-3 or caspase-9 activity was evaluated using a caspase-3 or caspase-9 activity assay kit, respectively. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assay were used to address the relationship among circ_0000524,miR-500a-5p and CXCL16. RESULTS: Upregulation of circ_0000524 and CXCL16 and low expression of miR-500a-5p were observed in MN tissues. AngII treatment induced the overexpression of circ_0000524 and CXCL16, a decrease of miR-500a-5p, and induced cell apoptosis in podocytes. Circ_0000524 negatively modulated the expression of miR-500a-5p. Circ_0000524 depletion inhibited podocyte apoptosis, which was rescued by loss of miR-500a-5p. miR-500a-5p contained the binding sites with CXCL16. Circ_0000524 knockdown hampered CXCL16 expression by upregulating miR-500a-5p expression. Additionally, miR-500a-5p upregulation suppressed AngII-induced podocyte apoptosis, which was rescued by enhanced expression of CXCL16. CONCLUSION: Circ_0000524/miR-500a-5p/CXCL16 pathway regulated podocyte apoptosis in MN.

An observation approach in evaluation of ozone production to precursor changes during the COVID-19 lockdown.

The increase of surface ozone during the Corona Virus Disease 2019 (COVID-19) lockdown in China has aroused great concern. In this study, we combine 1.5 years of measurements for ozone, volatile organic compounds (VOCs), and nitrogen oxide (NOX) at four sites to investigate the effect of COVID-19 lockdown on surface ozone in Dongguan, an industrial city in southern China. We show that the average concentrations of NOX and VOCs decreased by 70%-77% and 54%-68% during the lockdown compared to pre-lockdown, respectively. Based on the source apportionment of VOCs, the contribution of industrial solvent use reduced significantly (86%-94%) during the lockdown, and climbed back slowly along with the re-opening of the industry after lockdown. A slight increase in mean ozone concentration (3%-14%) was observed during the lockdown. The rise of ozone was the combined effect of substantial increase at night (58%-91%) and small reduction in the daytime (1%-17%). These conflicting observations in ozone response between day and night to emission change call for a more detailed approach to diagnostic ozone production response with precursor changes, rather than directly comparing absolute concentrations. We propose that the ratio of daily Ox (i.e. ozone + NO2) enhancement to solar radiation can provide a diagnostic parameter for ozone production response during the lockdown period. Smaller ratio of daily OX (ozone + NO2) enhancement to solar radiation during the lockdown were observed from the long-term measurements in Dongguan, suggesting significantly weakened photochemistry during the lockdown successfully reduces local ozone production. Our proposed approach can provide an evaluation of ozone production response to precursor changes from restrictions of social activities during COVID-19 epidemic and also other regional air quality abatement measures (e.g. public mega-events) around the globe.

High Concentrations of Atmospheric Isocyanic Acid (HNCO) Produced from Secondary Sources in China.

Isocyanic acid (HNCO) is a potentially toxic atmospheric pollutant, whose atmospheric concentrations are hypothesized to be linked to adverse health effects. An earlier model study estimated that concentrations of isocyanic acid in China are highest around the world. However, measurements of isocyanic acid in ambient air have not been available in China. Two field campaigns were conducted to measure isocyanic acid in ambient air using a high-resolution time-of-flight chemical ionization mass spectrometer (ToF-CIMS) in two different environments in China. The ranges of mixing ratios of isocyanic acid are from below the detection limit (18 pptv) to 2.8 ppbv (5 min average) with the average value of 0.46 ppbv at an urban site of Guangzhou in the Pearl River Delta (PRD) region in fall and from 0.02 to 2.2 ppbv with the average value of 0.37 ppbv at a rural site in the North China Plain (NCP) during wintertime, respectively. These concentrations are significantly higher than previous measurements in North America. The diurnal variations of isocyanic acid are very similar to secondary pollutants (e.g., ozone, formic acid, and nitric acid) in PRD, indicating that isocyanic acid is mainly produced by secondary formation. Both primary emissions and secondary formation account for isocyanic acid in the NCP. The lifetime of isocyanic acid in a lower atmosphere was estimated to be less than 1 day due to the high apparent loss rate caused by deposition at night in PRD. Based on the steady state analysis of isocyanic acid during the daytime, we show that amides are unlikely enough to explain the formation of isocyanic acid in Guangzhou, calling for additional precursors for isocyanic acid. Our measurements of isocyanic acid in two environments of China provide important constraints on the concentrations, sources, and sinks of this pollutant in the atmosphere.

Cryptotanshinone inhibits hypoxia/reoxygenation-induced oxidative stress and apoptosis in renal tubular epithelial cells.

Cryptotanshinone (CTS), an active component extracted from the root of Salvia miltiorrhiza Bunge , was reported to attenuate hepatic ischemia/reperfusion (I/R) injury. However, its protective effect against renal I/R injury remains unclear. In this study, the role of CTS in renal I/R injury in vitro and its possible mechanism were investigated. Our results showed that CTS improved cell viability in HK-2 cells exposed to hypoxia/reoxygenation (H/R). CTS also inhibited the H/R-mediated production of reactive oxygen species, as well as increased the activities of superoxide dismutase and catalase in H/R-stimulated HK-2 cells. In addition, CTS dramatically attenuated the induction of bax expression and caspase-3 activity and alleviated the reduction of bcl-2 expression in HK-2 cells cultured with H/R. Furthermore, CTS activated the levels of p-PI3K and p-Akt in H/R-injured HK-2 cells; meanwhile, the renal protective activity of CTS was inhibited by the inhibitor of the (phosphatidylinositol 3 kinase/protein kinase B) PI3K/Akt pathway (LY294002). These findings indicate that CTS can ameliorate renal I/R injury in vitro partly through regulating the PI3K/Akt pathway.

Interleukin-18.

A prospective observational study was conducted to evaluate the predictive value of interleukin-18 (IL-18) for major adverse cardiovascular events (MACEs) in hemodialysis patients. A total of 85 participants (45 hemodialysis patients and 40 healthy volunteers) with a mean age of 56.3 years were enrolled in this study. Demographic and clinical data were collected. MACE was used as the primary endpoint. Results showed that the hemodialysis patients had higher levels of IL-18 (701.6 ± 88.52 versus 152.0 ± 55.31 pg/mL, P < 0.01) and a high rate of MACE (15.6% versus 2.5%, P < 0.01) compared with healthy controls. Multiple linear regression analysis showed that the serum creatinine and left ventricular ejection fraction were significantly effective factors influencing IL-18 (P < 0.01). Receiver-operating characteristic curve analysis showed that IL-18 levels were better predictors for MACE. The area under the curve of IL-18 was 0.81 (0.70-0.92) (P = 0.004). IL-18 levels provided 87.5% sensitivity and 26% specificity with a threshold value of 534.5 pg/mL. Our findings indicated that hemodialysis patients with high levels of IL-18 had a high incidence rate of MACE. IL-18 is a good predictive marker of MACE in hemodialysis patients.

Knockdown of Angiopoietin-Like Protein 2 Ameliorates Diabetic Nephropathy by Inhibiting TLR4.

BACKGROUND/AIMS: Angiopoietin-like protein 2 (ANGPTL2) was reported to be implicated in the pathogenesis of inflammatory disease. Its role in diabetic nephropathy (DN) remained illdefined. METHODS: qRT-PCR and western blot analysis were performed to detect the expressions of ANGPTL2 or TLR4 in streptozotocin (STZ)-induced DN rats and HG-stimulated podocytes. The renal injury index including 24-h proteinuria, blood glucose level, serum creatinine and blood urea nitrogen were measured in DN rats using corresponding commercial kits. The effect of ANGPTL2 knockdown on the secretion or expression of inflammatory cytokines was detected by ELISA or qRT-PCR analysis. The effect of ANGPTL2 knockdown on extracellular matrix (ECM) accumulation was determined by testing TGF-ß1, Collagen-IV, fibronectin (FN) and PTEN expression via western blot. RESULTS: ANGPTL2 and TLR4 were both highly expressed in DN rats compared with control group. ANGPTL2 knockdown alleviated renal injury in STZ-induced DN rat model. ANGPTL2 knockdown also suppressed inflammatory cytokines (IL-6, TNF-α, MCP-1, IL-1ß) expression and ECM accumulation (TGF-ß1, Collagen-IV, FN, PTEN) in HG-induced podocytes. Moreover, ANGPTL2 knockdown led to a significant decrease of TLR4 expression in both DN rat and cell model. Furthermore, TAK-242 treatment exacerbated the inhibitory effect of ANGPTL2 knockdown on inflammatory cytokines expression and ECM accumulation in HG-induced podocytes. CONCLUSION: ANGPTL2 knockdown ameliorates DN by inhibiting TLR4 expression, an observation contributing to a better understanding of DN pathogenesis.

Silencing of TRB3 Ameliorates Diabetic Tubule Interstitial Nephropathy via PI3K/AKT Signaling in Rats.

BACKGROUND Nephropathy, a chronic progressive kidney disease often characterized by glomeruli scarring and sclerosis, is a major complication of diabetes mellitus. Development of nephropathologic lesions has been shown to be associated with suppressed AKT phosphorylation and elevated level of apoptosis. Moreover, it has been established that the TRB3 gene is capable of inhibiting AKT phosphorylation and promoting apoptosis. MATERIAL AND METHODS In this study, we injected TRB3 siRNA into Wistar rats with type 1 diabetes, and monitored development of nephropathy in the rats. Urinary albumin excretion and serum creatinine were used as primary indicators, and nephritic histology was also examined. We also measured the serum level of pro-inflammatory cytokines collagen expression, and phosphorylation of PI3K and AKT proteins in the kidneys. RESULTS By silencing the TRB3 gene with siRNA, diabetic-induced nephropathy symptoms were alleviated, such as increased serum creatinine level and urinary albumin secretion. Additionally, histological examination showed lower levels of nephropathic lesions, and samples of the kidneys showed less accumulation of collagen proteins. Levels of serum cytokines, including TNF-α, IL-1ß, and IL-6, were also lowered, whereas phosphorylation levels of PI3K and AKT were increased. In summary, TRB3 silencing in diabetic rats had a significant ameliorative effect on their nephropathy. CONCLUSIONS Silencing of TRB3 has a significant ameliorative effect on diabetic nephropathy in rats.

Safety and efficacy of cardioneuroablation for vagal bradycardia in a single arm prospective study.

Cardioneuroablation (CNA) is currently considered as a promising treatment option for patients with symptomatic bradycardia caused by vagotonia. This study aims to further investigate its safety and efficacy in patients suffering from vagal bradycardia. A total of 60 patients with vagal bradycardia who underwent CNA in the First Affiliated Hospital of Xinjiang Medical University from November 2019 to June 2022. Preoperative atropine tests revealed abnormal vagal tone elevation in all patients. First, the electroanatomic structures of the left atrium was mapped out by using the Carto 3 system, according to the protocol of purely anatomy-guided and local fractionated intracardiac electrogram-guided CNA methods. The upper limit of ablation power of superior left ganglion (SLGP) and right anterior ganglion (RAGP) was not more than 45W with an ablation index of 450.Postoperative transesophageal cardiac electrophysiological examination was performed 1 to 3 months after surgery. The atropine test was conducted when appropriate. Twelve-lead electrocardiogram, Holter electrocardiogram, and skin sympathetic nerve activity were reviewed at 1, 3, 6 and 12 months after operation. Adverse events such as pacemaker implantation and other complications were also recorded to analyze the safety and efficacy of CNA in the treatment of vagus bradycardia. Sixty patients were enrolled in the study (38 males, mean age 36.67 ± 9.44, ranging from 18 to 50 years old). None of the patients had a vascular injury, thromboembolism, pericardial effusion, or other surgical complications. The mean heart rate, minimum heart rate, low frequency, low/high frequency, acceleration capacity of rate, and skin sympathetic nerve activity increased significantly after CNA. Conversely, SDNN, PNN50, rMSSD, high frequency, and deceleration capacity of rate values decreased after CNA (all P < 0.05). At 3 months after ablation, the average heart rate, maximum heart rate, and acceleration capacity of heart rate remained higher than those before ablation, and the deceleration capacity of heart rate remained lower than those before ablation and the above results continued to follow up for 12 months after ablation (all P < 0.05). There was no significant difference in other indicators compared with those before ablation (all P > 0.05). The remaining 81.67% (49/60) of the patients had good clinical results, with no episodes of arrhythmia during follow-up. CNA may be a safe and effective treatment for vagal-induced bradycardia, subject to confirmation by larger multicenter trials.

Influence of ozone pollution on the mixing state and formation of oxygenated organics containing single particles.

The formation and aging processes of oxygenated organic molecules (OOMs) are important for understanding the formation mechanisms of secondary organic aerosols (SOAs) in the field. In this study, we investigated the mixing states of OOM particles by identifying several oxygenated species along with the distributions of secondary organic carbon (SOC) during both clean and ozone (O3)-polluted periods in July and September of 2022 in Guangzhou, China. OOM-containing particles accounted for 57 % and 49 % of the total detected single particles in July and September, respectively. Most of the OOM particles were internally mixed with sulfate and nitrate, while elemental carbon and hydrocarbon species were absent. Despite the higher SOC/OC ratio in September (81 %) than it in July (72 %), comparative investigations of the mass spectra, diurnal patterns, and distributions of OOM particles revealed the same composition and aging states of OOMs in two O3 pollution periods. As the O3 concentration increased from the clean to the polluted periods, the ratio of SOC to OC increased along with the relative abundance of secondary OOM particles among total OOM particles. In contrast, the relative abundance of OC-type OOM particles gradually decreased, indicating the conversion of hydrocarbon species into OOMs as the SOC/OC ratio increased. Both the bulk analysis of SOC from filter measurement and the mixing states of OOM particles suggested that OOM production and degree of oxidation were higher in the O3-polluted periods than in the clean periods. These results elucidate the effects of O3 pollution on the OOM formation process and offer new perspectives for the joint investigation of SOA production based on filter sampling and single-particle measurements.

Quantifying the contributions of meteorology, emissions, and transport to ground-level ozone in the Pearl River Delta, China.

Ozone pollution presents a growing air quality threat in urban agglomerations in China. It remains challenge to distinguish the roles of emissions of precursors, chemical production and transportations in shaping the ground-level ozone trends, largely due to complicated interactions among these 3 major processes. This study elucidates the formation factors of ozone pollution and categorizes them into local emissions (anthropogenic and biogenic emissions), transport (precursor transport and direct transport from various regions), and meteorology. Particularly, we attribute meteorology, which affects biogenic emissions and chemical formation as well as transportation, to a perturbation term with fluctuating ranges. The Community Multiscale Air Quality (CMAQ) model was utilized to implement this framework, using the Pearl River Delta region as a case study, to simulate a severe ozone pollution episode in autumn 2019 that affected the entire country. Our findings demonstrate that the average impact of meteorological conditions changed consistently with the variation of ozone pollution levels, indicating that meteorological conditions can exert significant control over the degree of ozone pollution. As the maximum daily 8-hour average (MDA8) ozone concentrations increased from 20 % below to 30 % above the National Ambient Air Quality Standard II, contributions from emissions and precursor transport were enhanced. Concurrently, direct transport within Guangdong province rose from 13.8 % to 22.7 %, underscoring the importance of regional joint prevention and control measures under adverse weather conditions. Regarding biogenic emissions and precursor transport that cannot be directly controlled, we found that their contributions were generally greater in urban areas with high nitrogen oxides (NOx) levels, primarily due to the stronger atmospheric oxidation capacity facilitating ozone formation. Our results indicate that not only local anthropogenic emissions can be controlled in urban areas, but also the impacts of local biogenic emissions and precursor transport can be potentially regulated through reducing atmospheric oxidation capacity.

Post-TAVR patients with atrial fibrillation: are NOACs better than VKAs?-A meta-analysis.

Objective: This study aimed to compare the efficacy of novel oral anticoagulants (NOACs) with traditional anticoagulants vitamin K antagonists (VKAs) in patients with atrial fibrillation (AF) post transcatheter aortic valve replacement (TAVR). Methods: Studies comparing the usage of NOACs and VKAs in AF patients with oral anticoagulant indication post-TAVR were retrieved from PubMed, EMBASE, Medline, and Cochrane databases from their building-up to Jan. 2023. The literature was screened in line of inclusion and exclusion criteria. Risk ratio (RR) or odds ratio (OR),95% confidence interval (CI) and number needed to treat (NNT) were calculated for four main indexes that composite endpoints composed mainly of any clinically relevant risk events, stroke, major bleeding, and all-cause mortality. Subsequently, a meta-analysis was performed using the RevMan5.3 and Stata 16.0 software. Results: In the aggregate of thirteen studies, contained 30388 post-TAVR patients with AF, were included in this meta-analysis. Our results indicated that there was no significant difference in stroke between the NOACs group and the VKAs group, and the NOACs group had a numerically but non-significantly higher number of composite endpoint events compared with the other group. Nevertheless, the incidence of major bleeding [11.29% vs. 13.89%, RR 0.82, 95%CI (0.77,0.88), P < 0.00001, I² = 69%, NNT = 38] and all-cause mortality [14.18% vs. 17.61%, RR 0.83, 95%CI (0.79,0.88), p < 0.00001, I² = 82%, NNT = 29] were significantly lower in the NOACs group than another group. Conclusion: Taken together, our data indicated that the usage of NOACs reduced the incidence of major bleeding and all-cause mortality compared to VKAs in post-TAVR patients with AF.

Photolysis frequency of nitrophenols derived from ambient measurements.

Nitrophenols, a class of important intermediate products from the oxidation of aromatics, can participate in photochemistry and influence the atmospheric oxidative capacity. However, the reported photolysis frequencies of nitrophenols show considerable discrepancies. Here, measurements of nitrophenol, and methyl nitrophenol using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) at both urban and regional sites in southern China are used to constrain photolysis frequencies of nitrophenols. Considerable concentrations with a campaign average of 58 ± 32 ppt for nitrophenol and 97 ± 59 ppt for methyl nitrophenol were observed at the regional site. Based on the in-situ measurement dataset, a steady-state calculation was performed along with a zero-dimensional box model to analyze the budgets of nitrophenols. The result indicates that both primary emission and photolysis have significant impacts on nitrophenols. Primary emission contributes up to 88 % of the total nitrophenols production while photolysis accounts for up to 98 % of the total removal rate. The dominant sink of nitrophenols is photolysis with a rate of about 3.5 % ± 1.3 % of jNO2 for nitrophenol and 2.4 % ± 1.0 % of jNO2 for methyl nitrophenol. The results of this study suggest that using advanced mass spectrometry to accurately measure ambient nitrophenols, supplemented by an observation-based box model for budget analysis, provides an important indication for determining photolysis rate constants of nitrophenols.

Feasibility, safety and effectiveness of mapping system assisted conduction system pacing: a single-center prospective study.

To assess pacing and electrophysiological parameters, as well as mid-term outcomes, among patients undergoing His bundle pacing (HBP) guided by KODEX-EPD (a novel mapping system). Consecutive patients undergoing conduction system pacing (CSP) for bradycardia indications were evaluated. Procedural and fluoroscopic times and pacing characteristics were compared between conventional fluoroscopy (the standard group, N = 20 cases) and KODEX-EPD mapping system guided group (the KODEX group, N = 20cases) at CSP implantation and all patients were followed at 6-month. HBP was achieved in all patients (the standard group 20/20 and the KODEX group 20/20). There was no difference in the mean procedure time between the two groups (63.7 ± 9.3 vs. 78.2 ± 25.1 min, p = 0.33). Compared with the standard group, the KODEX group significantly reduced the intraoperative X-ray exposure time (3.8 ± 0.5 vs. 19.3 ± 5.1 min, p < 0.05) and X-ray dose (23.6 ± 5.4 vs. 120.2 ± 38.3 mGy, p < 0.05). There were no significant differences in atrial impedance (643.0 ± 98.8 vs. 591.5 ± 92.1 Ω, p = 0.09), atrial sensing (2.9 ± 0.8 vs. 2.5 ± 0.8 mV, p = 0.08), ventricular sensing (12.8 ± 2.4 vs. 13.3 ± 3.3 mV, p = 0.63),atrial pacing threshold (1.0 ± 0.2 vs. 1.0 ± 0.1 V/0.4 ms, p = 0.81) and ventricular pacing threshold (1.0 ± 0.2 vs. 0.9 ± 0.1 V/0.4 ms, p = 0.63) between two groups, There were statistical differences in ventricular impedance (640.0 ± 80.3 vs. 702.0 ± 86.1 Ω, p < 0.05). There was no statistical significance in pacing parameters between the two groups at 6 months after procedure (p > 0.05). During the 6-months follow-up period, no adverse events occurred in the two groups. It can be concluded that KODEX-EPD can safely guide His bundle branch pacing lead implantation with reduced fluoroscopic time and dose without lengthening the procedure time.