An ultra-short-acting benzodiazepine in thalamic nucleus reuniens undermines fear extinction via intermediation of hippocamposeptal circuits.

Benzodiazepines, commonly used for anxiolytics, hinder conditioned fear extinction, and the underlying circuit mechanisms are unclear. Utilizing remimazolam, an ultra-short-acting benzodiazepine, here we reveal its impact on the thalamic nucleus reuniens (RE) and interconnected hippocamposeptal circuits during fear extinction. Systemic or RE-specific administration of remimazolam impedes fear extinction by reducing RE activation through A type GABA receptors. Remimazolam enhances long-range GABAergic inhibition from lateral septum (LS) to RE, underlying the compromised fear extinction. RE projects to ventral hippocampus (vHPC), which in turn sends projections characterized by feed-forward inhibition to the GABAergic neurons of the LS. This is coupled with long-range GABAergic projections from the LS to RE, collectively constituting an overall positive feedback circuit construct that promotes fear extinction. RE-specific remimazolam negates the facilitation of fear extinction by disrupting this circuit. Thus, remimazolam in RE disrupts fear extinction caused by hippocamposeptal intermediation, offering mechanistic insights for the dilemma of combining anxiolytics with extinction-based exposure therapy.

Nomogram for the prediction of infected pancreatic necrosis in moderately severe and severe acute pancreatitis.

OBJECTIVES: As a serious complication of moderately severe acute pancreatitis (MSAP) and severe acute pancreatitis (SAP), infected pancreatic necrosis (IPN) can lead to a prolonged course of interventional therapy. Most predictive models designed to identify such patients are complex or lack validation. The aim of this study was to develop a predictive model for the early detection of IPN in MSAP and SAP. METHODS: A total of 594 patients with MSAP or SAP were included in the study. To reduce dimensionality, least absolute shrinkage and selection operator regression analysis was used to screen potential predictive variables, a nomogram was then constructed using logistic regression analysis. The receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the discrimination, accuracy, and clinical efficacy of the model. External data were also obtained to further validate the constructed model. RESULTS: There were 476, 118, and 82 patients in the training, internal validation, and external validation cohorts, respectively. Platelet count, hematocrit, albumin/globulin, severity of acute pancreatitis, and modified computed tomography severity index score were independent factors for predicting IPN in MSAP and SAP. The area under the ROC curves were 0.923, 0.940, and 0.817, respectively, in the three groups. There was a good consistency between the actual probabilities and the predicted probabilities. DCA revealed excellent clinical utility. CONCLUSION: The constructed nomogram is a simple and feasible model that has good clinical predictive value and efficacy in clinical decision-making for IPN in MSAP and SAP.

Revealing the pharmacological mechanisms of nao-an dropping pill in preventing and treating ischemic stroke via the PI3K/Akt/eNOS and Nrf2/HO-1 pathways.

Nao-an Dropping Pill (NADP) is a Chinese patent medicine which commonly used in clinic for ischemic stroke (IS). However, the material basis and mechanism of its prevention or treatment of IS are unclear, then we carried out this study. 52 incoming blood components were resolved by UHPLC-MS/MS from rat serum, including 45 prototype components. The potential active prototype components hydroxysafflor yellow A, ginsenoside F1, quercetin, ferulic acid and caffeic acid screened by network pharmacology showed strongly binding ability with PIK3CA, AKT1, NOS3, NFE2L2 and HMOX1 by molecular docking. In vitro oxygen-glucose deprivation/reperfusion (OGD/R) experimental results showed that NADP protected HA1800 cells from OGD/R-induced apoptosis by affecting the release of LDH, production of NO, and content of SOD and MDA. Meanwhile, NADP could improve behavioral of middle cerebral artery occlusion/reperfusion (MCAO/R) rats, reduce ischemic area of cerebral cortex, decrease brain water and glutamate (Glu) content, and improve oxidative stress response. Immunohistochemical results showed that NADP significantly regulated the expression of PI3K, Akt, p-Akt, eNOS, p-eNOS, Nrf2 and HO-1 in cerebral ischemic tissues. The results suggested that NADP protects brain tissues and ameliorates oxidative stress damage to brain tissues from IS by regulating PI3K/Akt/eNOS and Nrf2/HO-1 signaling pathways.

Correction: An E-selectin targeting and MMP-2-responsive dextran-curcumin polymeric prodrug for targeted therapy of acute kidney injury.

Correction for 'An E-selectin targeting and MMP-2-responsive dextran-curcumin polymeric prodrug for targeted therapy of acute kidney injury' by Jing-Bo Hu et al., Biomater. Sci., 2018, 6, 3397-3409, https://doi.org/10.1039/C8BM00813B.

[Imaging study on thoracic and lumbar physiological curvature in adolescent idiopathic scoliosis].

OBJECTIVE: To observe the alteration of thoracic and lumbar physiological curvature in adolescent idiopathic scoliosis(AIS) and the difference of physiological curvature between different types of scoliosis. METHODS: A retrospective analysis was conducted on 305 adolescent patients taken full spine X-ray in our hospital from January 2017 to December 2021. The patients were divided into normal group and scoliosis group. The normal group was composed of 179 patients, 79 males and 100 females, aged 10 to 18 years old with an average of (12.84±2.10) years old, with cobb agle less than 10 degrees. The scoliosis group was composed of 126 patients, 33 males and 93 females, aged 10 to 18 years old with an average of (13.92±2.20) years old. The gender, age, Risser sign, thoracic kyphosis(TK) and lumbar lordosis(LL) in 2 groups were compared, and the TK and LL were also compared between different genders, different degrees of scoliosis and different segments of scoliosis. RESULTS: The female ratio(P=0.001) and age (P<0.001) in scoliosis group were higher than them in normal group; the ratio of low-grade ossification was higher in normal group than in scoliosis group(P=0.038). TK was significantly smaller in scoliosis group than in normal group(P<0.001), but there was no significant difference in LL between the 2 groups(P=0.147). There were no significant difference in TK and LL between male and female. The TK was significantly bigger in mild AIS patients than in moderate AIS patients(P<0.05), but there was no significant difference in LL between mild and moderate patients(P>0.05). The TK and LL in different segments scoliosis were not found significant difference. CONCLUSION: The physiological curvature of thoracic and lumbar spine is independent of gender. The thoracic physiological curvature becomes smaller in AIS patients, but lumbar curvature remains unchanged. The thoracic physiological curvature in mild AIS patients is greater than that in moderate AIS patients, but the lumbar curvature is almost unchanged between mild and moderate scoliosis and is similar with that in normal adolescent. The alteration of thoracic and lumbar physiological curvature in AIS patients may be related to relative anterior spinal overgrowth, and the specific detailed mechanism needs to be further studied.

[Correlation analysis of Cobb angle and linear spinous process angle in adolescent idiopathic scoliosis].

OBJECTIVE: To analyze the correlation between Cobb angle and spinous process angle (SPA) on X-ray film and body surface in patients with mild to moderate adolescent idiopathic scoliosis(AIS). To explore the possibility of linear SPA to assess scoliosis. METHODS: Retrospective study for correlation of Cobb angle and linear SPA on X-ray film. AIS patients treated and taken full spine anteroposterior X-ray from January 2019 to December 2021 were analyzed correlation of Cobb angle and linear SPA on X-ray film. Prospective study for correlation of Cobb angle and body linear SPA. AIS patients treated and taken full spine anteroposterior X-ray from December 1 to December 9 this year were analyzed correlation of Cobb angle and body linear SPA. RESULTS: A total of 113 AIS patients with age an average of (14.02±2.16) years old(ranged from 10 to 18 years old) were recruited in retrospective study, involving 26 males and 87 females;there were 71 patients with mild AIS and 42 patients with moderate AIS. Cobb angle in AIS patients was significantly inversely associated with SPA(r=-0.564, P<0.001), the linear regression equation was:Cobb angle=169.444-0.878×SPA. Cobb angles in patients with mild scoliosis were significantly and inversely associated with SPA(r=-0.269, P=0.012), the linear regression equation was:Cobb angle=46.832-0.185×SPA. Cobb angles in patients with moderate scoliosis were also clearly correlated with SPA(r=-0.417, P=0.003), the linear regression equation was:Cobb angle=113.889-0.516×SPA. Thirty-eight patients were recruited in prospective study. The mean Cobb angle and body linear SPA were(18.70±6.98)°, ranged from 11.3° to 36.0° and (170.34±4.57)°, ranged from 162.1° to 177.7° respectively. There was significantly negative correlation(r=-0.651, P<0.001), the linear regression equation is:Cobb angle=187.91-0.99×SPA. CONCLUSION: Linear SPA on X-ray film or on the body was significantly negatively correlated with Cobb angles, but the regression equation fits poorly, so it's not suitable for diagnosis of scoliosis;however, linear SPA is appropriate for self-controlled assessment of scoliotic therapy or for dynamic assessment of spinal flexibility.

Narrowband Ultraviolet-B Persistent Luminescence in an Indoor-Lighting Environment through Energy Transfer from Host Excitons to Gd3+ Emitters in ScPO4.

Narrowband ultraviolet-B (NB-UVB) luminescent materials are characterized by high photon energy, narrow spectral width, and visible-blind emission, thus holding great promise for photochemistry and photomedicine. However, most NB-UVB phosphors developed so far are photoluminescent, where continuous external excitation is needed. Herein, we realize NB-UVB persistent luminescence (PersL) in an indoor-lighting environment by exploiting the interaction between self-trapped/defect-trapped excitons and Gd3+ emitters in ScPO4. The phosphor shows a self-luminescing feature with a peak maximum at 313 nm with a time duration of >24 h after ceasing X-ray irradiation, which can be clearly imaged by an UVB camera in a bright environment. Spectroscopic and theoretical approaches reveal that thermo- and photo-stimulations of energies trapped at intrinsic lattice defects followed by energy transfer to Gd3+ emitters account for the emergence of the afterglow. The present results can initiate more exploration of NB-UVB PersL phosphors for emerging applications in secret optical tagging and phototherapy.

Giant cyst in heterotopic pregnancy: A case report.

BACKGROUND: The coexistence of a heterotopic pregnancy with a giant ovarian cyst is an incredibly rare abnormal pregnancy in cases of natural conception. The incidence of this condition has increased significantly as a result of the continuous development of assisted reproductive technologies. When this type of pregnancy occurs, both the continuation of intrauterine pregnancy and the life of the pregnant woman are severely threatened. Early diagnosis and treatment using safe and effective methods are paramount in this situation. CASE SUMMARY: A 30-year-old primigravida at a gestation age determined as 8 wk 4 d by scan was admitted to the hospital with heterotopic pregnancy and a right ovarian cyst. Laparoscopic resection of the ectopic pregnancy was performed, but the intrauterine pregnancy and ovarian cyst were preserved. CONCLUSION: The approach to a patient with heterotopic pregnancy and a giant ovarian cyst is individualized base on the fertility requirements. We recommend the following: (1) If the patient satisfies parity and has no fertility requirement, a laparoscopic salpingectomy should be performed and the giant ovarian cyst and intrauterine pregnancy removed; (2) If the patient has fertility requirements wishes to have more children in the future, laparoscopic salpingectomy or salpingostomy should be performed and the intrauterine pregnancy preserved. Serial ovarian cyst aspiration can be performed under ultrasound and resection can be done after delivery; and (3) Heterotopic pregnancy should be diagnosed early by active surveillance during antenatal visits using ultra sound as this is important for the avoidance of catastrophic complications.

Autophagy-related tumor subtypes associated with significant gene expression profiles and immune cell infiltration signatures to reveal the prognosis of non-small cell lung cancer.

Autophagy plays an important role in non-small cell lung cancer (NSCLC). We aimed to establish novel autophagy-related tumor subtypes to distinguish the prognosis of NSCLC. In this study, gene expression profiles, mutation data and clinical information obtained from the Cancer Genome Atlas. Kaplan Meier-plotter could evaluate prognostic value of autophagy-related genes. Consensus clustering revealed autophagy-related tumor subtypes. Gene expression profiles, mutation data and immune infiltration signatures were identified, oncogenic pathways and gene-drug interactions were performed according to the clusters. Finally, a total of 23 prognostic genes were screened and consensus clustering analysis divided the NSCLC into 2 clusters. The mutation signature showed that 6 genes are special. Immune infiltration signatures showed that higher fraction of immune cells was associated with cluster 1. The oncogenic pathways and gene-drug interactions also showed different patterns. In conclusion, autophagy-related tumor subtypes have different prognosis. Understanding the subtypes of NSCLC are helpful to accurately identify the NSCLC and personalized treatment.

[Spatio-temporal Distribution Characteristics of Secondary Aerosol in Beijing-Tianjin-Hebei Urban Agglomeration in Winter].

The secondary component is an important factor causing PM2.5 pollution in the Beijing-Tianjin-Hebei urban agglomeration in winter. In this study, the CO tracer method was used to estimate the secondary PM2.5 concentration of the Beijing-Tianjin-Hebei urban agglomeration in the winter of 2017-2021. The temporal and spatial distribution characteristics were analyzed, and the influencing factors of regional secondary PM2.5 were discussed. The results showed that the decreasing trend of PM2.5 concentration in the Beijing-Tianjin-Hebei Region in the winter of 2017-2021 was obvious, and the cities with the largest decline were located in the central and southern part of Hebei Province, mainly contributed by primary PM2.5. There was a good correlation between secondary PM2.5 and PM2.5 in all cities of the Beijing-Tianjin-Hebei urban agglomeration, and the proportion of secondary PM2.5 in Beijing and Tianjin was significantly higher than that in other cities. With the aggravation of pollution degree, the mass concentration of primary PM2.5 and secondary PM2.5 increased in varying degrees, and the proportion of secondary PM2.5 increased significantly. Compared with the direct measurement results, the estimated value obtained by this method was lower as a whole. The selection of appropriate primary aerosol reference value was the key to improving this method and estimating the secondary PM2.5 concentration.

Does information disclosure among public hospitals stimulate medical cost change efforts? A pilot study in Shanghai.

BACKGROUND: In 2013, the Shanghai Hospital Development Center issued a policy to advocate public hospitals to report their information about costs on diseases. The objective was to evaluate the impact of interhospital disclosure of costs on diseases on medical costs and compare costs per case following information disclosure between hospitals of different rankings. METHODS: The study uses the hospital-level performance report issued by Shanghai Hospital Development Center in the fourth quarter of 2013, which covers quarterly aggregated hospital-level discharge data from 14 tertiary public hospitals participating in thyroid malignant tumors and colorectal malignant tumors information disclosure from the first quarter of 2012 to the third quarter of 2020. An interrupted time series model with segmented regression analysis is employed to examine changes in quarterly trends with respect to costs per case and length of stay before and after information disclosure. We identified high- and low-cost hospitals by ranking them on a costs per case basis per disease group. RESULTS: This research identified significant differences in cost changes for thyroid malignant tumors and colorectal malignant tumors between hospitals after disclosing information. A hospital's discharge costs per case for thyroid malignant tumors increased significantly among top-cost hospitals (1629.251 RMB, P = 0.019), while decreased for thyroid and colorectal malignant tumors among low-cost hospitals (-1504.189 RMB, P = 0.003; -6511.650 RMB, P = 0.024, respectively). CONCLUSION: Our findings indicate that information disclosure of costs on diseases results in changes in discharge costs per case. And low-cost hospitals continued to maintain their leading edge, whereas the high-cost hospitals changed their position in the industry by reducing discharge costs per case after information disclosure.

Impact of Diagnosis-Related Groups on Inpatient Quality of Health Care: A Systematic Review and Meta-Analysis.

The aim of this meta-analysis was to comprehensively evaluate the effectiveness of Diagnosis-related group (DRG) based payment on inpatient quality of care. A comprehensive literature search was conducted in PubMed, EMBASE, Cochrane Central Register of Controlled Trials and Web of Science from their inception to December 30, 2022. Included studies reported associations between DRGs-based payment and length of stay (LOS), re-admission within 30 days and mortality. Two reviewers screened the studies independently, extracted data of interest and assessed the risk of bias of eligible studies. Stata 13.0 was used in the meta-analysis. A total of 29 studies with 36 214 219 enrolled patients were analyzed. Meta-analysis showed that DRG-based payment was effective in LOS decrease (pooled effect: SMD = -0.25, 95% CI = -0.37 to -0.12, Z = 3.81, P < .001), but showed no significant overall effect in re-admission within 30 days (RR = 0.79, 95% CI = 0.62-1.01, Z = 1.89, P = .058) and mortality (RR = 0.91, 95% CI = 0.72-1.15, Z = 0.82, P = .411). DRG-based payment demonstrated statistically significant superiority over cost-based payment in terms of LOS reduction. However, owing to limitations in the quantity and quality of the included studies, an adequately powered study is necessary to consolidate these findings.

How do inpatients' costs, length of stay, and quality of care vary across age groups after a new case-based payment reform in China? An interrupted time series analysis.

CONTEXT: A patient classification-based payment system called diagnosis-intervention packet (DIP) was piloted in a large city in southeast China in 2018. OBJECTIVE: This study evaluates the impact of DIP payment reform on total costs, out-of-pocket (OOP) payments, length of stay (LOS), and quality of care in hospitalised patients of different age. METHODS: An interrupted time series model was employed to examine the monthly trend changes of outcome variables before and after the DIP reform in adult patients, who were stratified into a younger (18-64 years) and an older group (≥ 65 years), further stratified into young-old (65-79 years) and oldest-old (≥ 80 years) groups. RESULTS: The adjusted monthly trend of costs per case significantly increased in the older adults (0.5%, P = 0.002) and oldest-old group (0.6%, P = 0.015). The adjusted monthly trend of average LOS decreased in the younger and young-old groups (monthly slope change: -0.058 days, P = 0.035; -0.025 days, P = 0.024, respectively), and increased in the oldest-old group (monthly slope change: 0.107 days, P = 0.030) significantly. The changes of adjusted monthly trends of in-hospital mortality rate were not significant in all age groups. CONCLUSION: Implementation of the DIP payment reform associated with increase in total costs per case in the older and oldest-old groups, and reduction in LOS in the younger and young-old groups without deteriorating quality of care.

Development and validation of a predictive model for patients with post-extubation dysphagia.

BACKGROUND: Swallowing disorder is a common clinical symptom that can lead to a series of complications, including aspiration, aspiration pneumonia, and malnutrition. This study aimed to investigate risk factors of post-extubation dysphagia (PED) in intensive care unit (ICU) patients with endotracheal intubation, and to develop a risk-predictive model for PED, which could serve as an assessment tool for the prevention and control of PED. METHODS: Patients retrospectively selected from June to December 2021 in a tertiary hospital served as the derivation cohort. Patients recruited from the same hospital from March to June 2022 served as the external validation cohort for the predictive model. We used a combination of variable screening and least absolute shrinkage and selection operator (LASSO) regression to select the most useful candidate predictors and checked the multicollinearity of independent variables using the variance inflation factor method. Multivariate logistic regression analysis was performed to calculate the odds ratio (OR; 95% confidence interval [95% CI]) and P-value for each variable to predict diagnosis. The screened risk factors were introduced into R software to build a nomogram model. The performance of the model, including discrimination ability, calibration, and clinical benefit, was evaluated by plotting the receiver operating characteristic (ROC), calibration, and decision curves. RESULTS: A total of 305 patients were included in this study. Among them, 235 patients (53 PED vs. 182 non-PED) were enrolled in the derivation cohort, while 70 patients (17 PED vs. 53 non-PED) were enrolled in the validation cohort. The independent predictors included age, pause of sedatives, level of consciousness, activities of daily living (ADL) score, nasogastric tube, sore throat, and voice disorder. These predictors were used to establish the predictive nomogram model. The model demonstrated good discriminative ability, and the area under the ROC curve (AUC) was 0.945 (95% CI 0.904-0.970). Applying the predictive model to the validation cohort demonstrated good discrimination with an AUC of 0.907 (95% CI 0.831-0.983) and good calibration. The decision-curve analysis of this nomogram showed a net benefit of the model. CONCLUSION: A predictive model that incorporates age, pause of sedatives, level of consciousness, ADL score, nasogastric tube, sore throat, and voice disorder may have the potential to predict PED in ICU patients.

Construction of an early warning model of hepatic encephalopathy in patients with liver cirrhosis based on psychological testing.

AIMS AND OBJECTIVES: To establish an early warning model of hepatic encephalopathy in patients with liver cirrhosis based on psychological testing. METHODS: Data including patient demographics, number connection test-A (NCT-A), digit symbol test (DST), Model for End-Stage Liver Disease (MELD) scores were collected for patients admitted to a tertiary hospital in Shanghai with liver cirrhosis between January and December 2019. Patients were divided into two groups based on the development of hepatic encephalopathy (the hepatic encephalopathy group and non-hepatic encephalopathy group). Risk factors for hepatic encephalopathy in patients with liver cirrhosis were determined by using the binary logistic regression. We developed a predictive model in accordance with the STARD statement criteria (Supplementary File S1) with a cut-off value determined by receiver operating characteristic (ROC) curve analysis and calculation of the Youden index. RESULTS: A total of 417 patients with liver cirrhosis were included in the present study. Of these, 33 out of 66 patients with abnormal psychological tests had hepatic encephalopathy during hospitalisation. In contrast, 6 out of 317 patients with normal psychological tests had hepatic encephalopathy. Logistic regression analysis identified age, MELD score, and abnormal psychological tests as risk factors for hepatic encephalopathy in patients with liver cirrhosis. The area under the ROC curve for our prediction model for hepatic encephalopathy in patients with liver cirrhosis was 0.950 and the largest calculated Youden index was 0.804, which corresponds to a cut-off value is 0.0307. CONCLUSION: Greater age, higher MELD score and abnormal psychological tests were significantly associated with increased risk of hepatic encephalopathy indicating early warning systems and identification of abnormal psychological tests are important components of the clinical nursing care process for cirrhotic patients. Our early warning model based on psychological testing can provide a basis for nursing observation and prevention of hepatic encephalopathy. RELEVANCE TO CLINICAL PRACTICE: Risk assessments for hepatic encephalopathy according to liver function and psychological tests, in addition to traditional neurological observations and dietary guidance, have utility in decreasing the incidence of hepatic encephalopathy.

[Regulation of Toll-like receptors and their downstream factors by butyrate].

Butyrate, normally produced by probiotics in the gut, not only provides energy for cells, but also changes the phosphorylation, acetylation and methylation levels of many proteins in cells. As a result, it affects the expression of many genes and the transmission of cell signals. Through G protein-coupled receptors, butyrate promotes the secretion of intestinal mucus and the formation of epithelial barriers, and attenuates the impacts of the pathogenic bacteria and their metabolites on human body. The Toll-like receptors (TLRs) are a group of pattern recognition receptors, and their activation causes the translocation of nuclear factor κB (NF-κB) from the cytoplasm to the nucleus and eventually leads to expression and secretion of various pro-inflammatory factors and chemokines. The expression of TLRs is also involved in the pathogenesis of some inflammatory diseases and tumors. The purpose of this review is to summarize the effects of butyrate on TLRs and their downstream signaling pathways. We not only summarized the production of butyrate, the expression of TLRs and the influence of their interaction on the body under the conditions of inflammation and tumor, but also discussed the potential role of butyrate as a bacterial metabolite in the treatments of some human diseases.

Yikang decoction facilitates embryo implantation in mice with implantation dysfunction via upregulation of LIF expression.

OBJECTIVE: The present study investigates the effects and mechanisms of Yikang decoction on embryo implantation in mice. METHODS: Totally, mature female mice were randomly divided into four groups: normal, implantation failure (mifepristone treatment), Yikang decoction treatment (mifepristone and Yikang decoction treatment), and control (mifepristone and physiological saline treatment) groups. The efficacy of Yikang decoction was evaluated by the adhesion of uterine endometrial cells. The expression of leukemia inhibitory factor (LIF) and integrin αvß3 in the endometrium were detected by real-time quantitative PCR and western blot. In addition, mouse endometrial cells were transfected with LIF specific siRNA-1, and the expression of LIF and αvß3 were detected. RESULTS: The number of embryos markedly decreased after mifepristone treatment. The adhesion of endometrial cells in the Yikang decoction treatment group significantly increased, when compared to the control group. The expression of LIF and integrin αvß3 was significantly reduced by mifepristone, but the attenuated expression of LIF and αvß3 was markedly reversed by treatment with Yikang decoction. In addition, after LIF siRNA-1 transfection, the expression of integrin αvß3 significantly decreased (P < 0.01). The correlation analysis revealed a significant positive correlation between LIF and αvß3 protein expression. CONCLUSION: Yikang decoction can regulate the expression of αvß3 and increase cell adhesion by upregulating the expression of LIF, thereby improving embryo implantation in mice. These data suggest that Yikang decoction may have therapeutic effect in treating infertility.

[Impacts of Changes in Meteorological Conditions During COVID-19 Lockdown on PM2.5 Concentrations over the Jing-Jin-Ji Region].

The Chinese government triggered the immediate implementation of a lockdown policy in China following the outbreak of the COVID-19 pandemic, leading to drastic decreases in air pollutant emissions. However, concentrations of PM2.5 and other pollutants increased during the COVID-19 lockdown over the Jing-Jin-Ji region compared with those averaged over 2015-2019, and two PM2.5 pollution events occurred during the lockdown. Using the ERA5 reanalysis data, we found that the Jing-Jin-Ji region during the COVID-19 lockdown was characterized by higher relative humidity, lower planetary boundary layer height, and anomalous updraft. These conditions were favorable for condensation and the secondary formation of aerosols and prevented turbulent diffusion of pollutants. Furthermore, we conducted sensitivity tests using the WRF-Chem model and found that ρ(PM2.5) increased by 20-55 µg·m-3(60%-170%) over the middle region of Jing-Jin-Ji during the COVID-19 lockdown due to changes in meteorological conditions. Furthermore, the enhanced aerosol chemistry and unfavorable diffusion conditions were identified as the key factors driving increases in PM2.5 concentrations during the lockdown. Planetary boundary layer height and relative humidity may become the important factors in forecasting PM2.5 pollution events over the Jing-Jin-Ji region under the background of emission reduction.

[Exploring Formation of Ozone in Typical Cities in Beijing-Tianjin-Hebei Region Using Process Analysis].

As the problem of O3 pollution in the Beijing-Tianjin-Hebei region becomes increasingly prominent, it is of great significance to explore and analyze the ozone variation characteristics and causes of the pollution process in the Beijing-Tianjin-Hebei region for regional air pollution prevention and control. The observations in this study showed that high O3 concentration in spring and summer of the Beijing-Tianjin-Hebei region was higher in the south and lower in the north. The high O3 concentration in Beijing, Tianjin, and Shijiazhuang was often accompanied by the influence of southern wind. Based on WRF-Chem model simulation and process analysis technology, the variation characteristics and causes of O3 in The Beijing-Tianjin-Hebei region in 2019 were deeply analyzed. The diurnal variations in chemical processes, vertical mixing, and transportation in typical cities showed distinct seasonal variations. In summer afternoons, chemical processes were the main source of O3 concentration increase in each city. Vertical mixing resulted in an increase in O3 concentration in Tianjin and Shijiazhuang but a decrease in Beijing. Tianjin and Shijiazhuang had a net output, whereas Beijing had a net inflow. In the polluted O3 process, the chemical process dominated the afternoon O3 concentration increasing in Beijing and Shijiazhuang, whereas vertical mixing dominated in Tianjin. In addition, there was a net input of O3 in Beijing and Shijiazhuang and a net output of O3 in Tianjin. In the clean O3 process, vertical mixing dominated the increase in O3 concentration in Beijing and Shijiazhuang in the afternoon, whereas in Tianjin it was chemical processes. At the same time, the net output of O3 existed in all three cities.