Exploring efficient strategies for air quality improvement in China based on its regional characteristics and interannual evolution of PM2.5 pollution.

Fine particulate matter (PM2.5) harms human health and hinders normal human life. Considering the serious complexity and obvious regional characteristics of PM2.5 pollution, it is urgent to fill in the comprehensive overview of regional characteristics and interannual evolution of PM2.5. This review studied the PM2.5 pollution in six typical areas between 2014 and 2022 based on the data published by the Chinese government and nearly 120 relevant literature. We analyzed and compared the characteristics of interannual and quarterly changes of PM2.5 concentration. The Beijing-Tianjin-Hebei region (BTH), Yangtze River Delta (YRD) and Pearl River Delta (PRD) made remarkable progress in improving PM2.5 pollution, while Fenwei Plain (FWP), Sichuan Basin (SCB) and Northeast Plain (NEP) were slightly inferior mainly due to the relatively lower level of economic development. It was found that the annual average PM2.5 concentration change versus year curves in the three areas with better pollution control conditions can be merged into a smooth curve. Importantly, this can be fitted for the accurate evaluation of each area and provide reliable prediction of its future evolution. In addition, we analyzed the factors affecting the PM2.5 in each area and summarize the causes of air pollution in China. They included primary emission, secondary generation, regional transmission, as well as unfavorable air dispersion conditions. We also suggested that the PM2.5 pollution control should target specific industries and periods, and further research need to be carried out on the process of secondary production. The results provided useful assistance such as effect prediction and strategy guidance for PM2.5 pollution control in Chinese backward areas.

Investigations on the thermoelectric and thermodynamic properties of Y2CT2 (T = O, F, OH).

Using the first-principle calculations combined with the Boltzmann transport theory, we studied the thermoelectric properties of Y2CT2 (T = O, F, OH) MXenes. Specifically, the Seebeck coefficient, thermal and electrical conductivities under constant relaxation time approximation were calculated. Results show that for p-type carriers, Y2CO2 has the largest power factor of up to 0.0017 W m-1 K-2 when the carrier concentration is 4.067 × 1013 cm-2 at 900 K, at the same temperature, for n-type carriers, the concentration is 9.376 × 1013 cm-2, the power factor in Y2C(OH)2 is 0.0026 W m-1 K-2. In particular, the figure of merit in Y2CF2 is 1.38 at 900 K because of its low thermal conductivity, indicating that it can be considered a potential medium-temperature thermoelectric material. In addition, the thermodynamics properties within 32 GPa and 900 K, such as bulk modulus, heat capacity and thermal expansion, are also estimated using the quasi-harmonic Debye model. Our results may offer some valuable hints for the potential application of Y2CT2 (T = O, F, OH) in the thermoelectric field.

[Characteristics of Carbonaceous Aerosol Pollution in PM2.5 in Xi'an].

Mass concentration, seasonal variation and sources of organic carbon (OC), element carbon (EC), methanol-soluble organic carbon (MSOC), and seven carbon components (OC1-4, EC1-3) were detected by thermal-optical analysis of 353 PM2.5 samples in Xi'an in 2017. The results show that the average mass concentrations of OC, EC, and MSOC were (17.56±11.83), (4.08±2.95) and (11.10±6.77) µg·m-3, respectively. The seasonal trend of the OC concentration follows the order winter > spring > summer > autumn. The seasonal trend in EC concentration follows the order winter > spring≈autumn > summer. The average MSOC/OC value is 0.64±0.20. The highest value is observed in winter and the lowest in summer. The correlation between OC and EC is good in spring (r2=0.76), but the correlation is poor in winter (r2=0.43). These results indicate that the source of the carbon aerosols was different. The content of secondary organic aerosols was estimated by the EC tracing method. The average mass concentration of SOC accounted for 51.9%, 38.4%, 37.3% and 44.0% of OC in spring, summer, autumn, and winter, respectively. The main sources of carbonaceous aerosols were analyzed by principal component analysis. The results show that carbonaceous aerosols originate mainly from coal and vehicle emissions in Xi'an.

CDC42-interacting protein 4 promotes metastasis of nasopharyngeal carcinoma by mediating invadopodia formation and activating EGFR signaling.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a common malignancy in Southern China and Southeast Asia. In this study, we investigated the functional and molecular mechanisms by which CDC42-interacting protein 4 (CIP4) influences NPC. METHODS: The expression levels of CIP4 were examined by Western blot, qRT-PCR or IHC. MTT assay was used to detect the proliferative rate of NPC cells. The invasive abilities were examined by matrigel and transwell assay. The metastatic abilities of NPC cells were revealed in BALB/c nude mice. RESULTS: We report that CIP4 is required for NPC cell motility and invasion. CIP4 promotes the activation of N-WASP that controls invadopodia formation and activates EGFR signaling, which induces downstream MMP2 (matrix metalloproteinase 2) upregulation. In addition, CIP4 could promote NPC metastasis by activating the EGFR pathway. In nude mouse models, distant metastasis was significantly inhibited in CIP4-silenced groups. High CIP4 expression is an independent adverse prognostic factor of overall survival (OS) and distant metastasis-free survival (DMFS). CONCLUSION: We identify the critical role of CIP4 in metastasis of NPC which suggest that CIP4 may be a potential therapeutic target of NPC patients.