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The oxidative potential (OP) of ambient particulate matter (PM) is a common metric for estimating PM toxicity and linking PM exposure to adverse health effects. Organic aerosol (OA), a dominant fraction of ambient PM worldwide, may significantly contribute to PM toxicity. Here, we investigated the source‐based OA components contributing to the OP of PM in the urban (Beijing, summer and winter) and rural (Gucheng, winter) environments of the North China Plain (NCP). Various OA components as identified by the aerosol mass spectrometer/aerosol chemical speciation monitor (AMS/ACSM), transition metals, and black carbon were compared with the OP of PM measured by dithiothreitol assays. The results consistently demonstrate the importance of OA as a contributor to PM's OP in both urban and rural NCP environments. Higher intrinsic OP was observed in winter Beijing than in summer, possibly due to OA being predominantly from anthropogenic sources in winter. Furthermore, different OA components were found to drive the response of OP in the two environments. More‐oxidized oxygenated OA (MO‐OOA), cooking OA, and oxidized primary OA (during winter) are the OA contributors to OP in the urban environment, with a dominant contribution from MO‐OOA. In contrast, biomass burning OA (BBOA) and OOA play a major role in the OP in the rural environment, with BBOA making the largest contribution. Overall, this work highlights the significance of OA in determining PM's OP and calls for more work to reveal the sources and characteristics of OA components contributing to OP across different regions. Plain Language Summary: Ambient fine particulate matter (PM2.5) is a top risk factor for human health. The oxidative potential (OP) of PM2.5 is widely used to estimate PM2.5 toxicity and link PM2.5 exposure with its adverse health effects. Organic aerosol (OA) constitutes a major fraction of PM2.5 and can contribute substantially to the OP of PM2.5. But OA is also a complex mixture comprised of thousands of compounds each with widely different health effects. Here, we reveal the key OA components driving the OP in the urban and rural environments of the NCP. We find that more‐oxidized oxygenated OA, which is highly oxidized and can be formed from multiple atmospheric processes, is a dominant contributor to the OP in the urban environment. In contrast, biomass burning OA makes the largest contribution to the OP in the rural environment. In sum, different OA components are found to be the main drivers of the OP in the two environments. More studies are warranted to further our understanding of the causes, sources, and characteristics of the PM2.5 OP over a wide range of geographical regions. Key Points: Seasonal and spatial variations of oxidative potential (OP) of ambient particulate matter are foundOrganic aerosol (OA) is an important contributor to the oxidative potential in both urban and rural environmentsMore‐oxidized oxygenated OA and biomass burning OA have a dominant contribution to the OP in urban and rural environments, respectively [ABSTRACT FROM AUTHOR]

Semi-hydrogenation of alkynes to alkenes using electrochemical approaches is an appealing alternative to conventional thermocatalytic strategies, as it efficiently utilizes water as the hydrogen source at ambient temperature. However, the precise modulation of atomic and electronic structures of catalytic Pd active sites remains a persistent challenge, particularly in enhancing the conversion yield of alkynes and improving the selectivity of alkenes. Here, we synthesize Pd nanoparticles anchored onto the surface of the defective two-dimensional Fe2O3 support, referred to as Pd/Fe2O3 catalysts, to conduct the electrocatalytic semi-hydrogenation of alkynes. Intriguingly, we observed the reconstruction of the atomic structure and configuration of Pd nanoparticles in the Pd/Fe2O3 catalysts due to metal–support interaction, caused by the hybridization of Pd d and O p orbitals. This interaction significantly weakens the binding strength of Pd sites in the Pd/Fe2O3 catalysts to the chemisorbed 4-aminophenylacetylene and reactive hydrogen intermediates. Consequently, Pd/Fe2O3 catalysts achieve a high conversion rate (99%) and selectivity (99%) in the semi-hydrogenation of 4-aminophenylacetylene coupled with high faradaic efficiency, outperforming both benchmark commercial Pd/C and other reference catalysts. Additionally, terminal alkynes featuring diverse functionalized groups, including those with easily reducible or passivated functionalities, can be efficiently semi-hydrogenated using Pd/Fe2O3 catalysts. [ABSTRACT FROM AUTHOR]

Variance or complete loss of the avirulence gene (Avr) enables the pathogen to escape resistance protein (R) recognition. The field resistance effectiveness of the R gene is determined by its corresponding Avr gene in field isolates. To effectively deploy the rice blast R gene Pi54, the distribution, variation and evolution of the corresponding Avr gene, AvrPi54, were determined through PCR amplification, pathogenicity assay, gene sequences and evolutionary analysis. Among 451 Pyricularia isolates from rice and non-rice hosts, including Oryza rufipogon, Digitaria sanguinalis, Eleusine coracana, E. indica and Musa sp. in Yunnan province, the PCR amplification result showed that AvrPi54 alleles existed among 218 (48.3%) isolates including rice isolates, O. rufipogon isolates and E. coracana isolates. Pathogenicity assay showed that 336 (74.5%) isolates were avirulent to Tetep (holding Pi54). Five AvrPi54 haplotypes were identified among 142 isolates through the gene sequence. These haplotypes were determined to be avirulent to Pi54 through pathogenicity assay. Four novel haplotypes (H2 to H5) of the AvrPi54 gene would provide new target sites for rice blast control. Haplotype diversity analysis indicated that there existed a lower genetic diversity of AvrPi54 for P. oryzae populations (five haplotypes, Hd = 0.127, π = 2.9 × 10−4) in this study. Neutrality tests showed that AvrPi54's genetic variation was affected by purified selection. Haplotype network and phylogeny analysis showed that H1 was an ancestral haplotype and was widely distributed in rice isolates and O. rufipogon isolates, while H5 diverged early and evolved independently. These results indicate that the gene evolves slowly and stably and is a comparatively conserved Avr gene. [ABSTRACT FROM AUTHOR]

Objective To investigate the effect of estradiol valerate (E2V) on endometrial receptivity induced by clomiphene in polycystic ovary syndrome (PCOS) rats. Methods Rats were divided into control group (administered 0.9% sodium chloride solution), and PCOS model group (administered 50 mg/kg clomiphene), E2V low, medium and high-dose intervention group [administered (0.2, 0.5, 1.0)mg/kg E2V+50 mg/kg clomiphene]. Serum sex hormone level was compared. Morphological change of endometrium was examined by ELISA. The expression of estrogen receptor (ER), progesterone receptor (PR), homeobox gene (Hox)A10, empty ventilator homeobox (Emx)2, integrin αvβ3 mRNA and protein in the endometrium were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blot. Results Compared with the control group, luteinizing hormone/follicle-forming hormone (LH/FSH), testosterone (T), relative expressions of Emx2 mRNA and protein were significantly increased (P＜0.05), while estradiol (E2) level, glandular area, glandular area, endometrial thickness and glandular/interstitial area ratio, relative expressions of ER, PR, HoxA10, integrin αvβ3 mRNA and protein were significantly decreased (P＜0.05). Compared with PCOS model group, the changes of above indexes in E2V low, medium and high-dose intervention group were opposite (P＜0.05). Conclusions E2V can improve endometrial receptivity of PCOS clomiphene-induced ovulation rats. E2V is potentially related to the up-regulation of ER, PR, HoxA10, integrinαvβ3 and down-regulation of Emx2.