Enhanced natural releases of mercury in response to the reduction in anthropogenic emissions during the COVID-19 lockdown by explainable machine learning

The wide spread of the coronavirus (COVID-19) has significantly impacted the global human activities. Compared to numerous studies on conventional air pollutants, atmospheric mercury that has matched sources from both anthropogenic and natural emissions is rarely investigated. At a regional site in eastern China, an intensive measurement was performed, showing obvious decreases in gaseous elemental mercury (GEM) during the COVID-19 lockdown, while it was not as significant as most of the other measured air pollutants. Before the lockdown, when anthropogenic emissions dominated, GEM showed no correlation with temperature and negative correlations with wind speed and the height of the boundary layer. In contrast, GEM showed significant correlation with temperature, while the relationship between GEM and the wind speed/boundary layer disappeared during the lockdown, suggesting the enhanced natural emissions of mercury. By applying a machine learning model and the SHAP (SHapley Additive exPlanations) approach, it was found that the mercury pollution episodes before the lockdown were driven by anthropogenic sources, while they were mainly driven by natural sources during and after the lockdown. Source apportionment results showed that the absolute contribution of natural surface emissions to GEM unexpectedly increased (44 %) during the lockdown. Throughout the whole study period, a significant negative correlation was observed between the absolute contribution of natural and anthropogenic sources to GEM. We conclude that the natural release of mercury could be stimulated to compensate for the significantly reduced anthropogenic GEM via the surface-air exchange in the balance of mercury.

Evaluation and prediction of high-quality development in China: A time-spatial analysis from Hubei province

High-quality sustainable development is the common goal pursued by all countries in the world. China's high-quality development (HQD) includes five concepts of "innovation, coordination, green, opening-up, and sharing ". In this context, we established an evaluation system that included these five fundamental characteristics, used the comprehensive entropy method and BP neural network to evaluate and predict the high-quality development of Hubei Province in China, and conducted a spatiotemporal deductive analysis. The study found that: 1) Economic growth still has an important impact on HQD, for all the five main indicators, "opening-up " and "innovation " have the highest impact weights, which are 0.379 and 0.278, respectively, while the proportions of coordination and sharing are both less than 0.1. 2) There are huge differences in the level of high-quality development between regions in Hubei Province. From 2010 to 2020, the average comprehensive index of Wuhan City was greater than 0.5, which is 7 times that of the second Xiangyang City, and 46 times that of the last Shennongjia district. 3) In the past few years, the overall high-quality development of Hubei Province has shown a fluctuating upward trend. However, due to the impact of COVID-19, during the following years, its comprehensive development index will decline by an average of 5% annually, but starting from 2022, it will gradually increase. As a result, tailored and coordinated sustainable environmental policies of integrating institutional and open-market measures should be provided.

A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Ralinepag to Improve Treatment Outcomes in Subjects with Pulmonary Arterial Hypertension (ADVANCE OUTCOMES)

RATIONALE: Pulmonary arterial hypertension (PAH) is a rare, progressive disease leading to right ventricular failure and premature death. The functional limitation and survival of patients with PAH remains unsatisfactory. Ralinepag, an orally available, potent, and selective, nonprostanoid, prostacyclin receptor agonist, is a new chemical entity in development to treat PAH. METHODS: The ADVANCE OUTCOMES (NCT03626688) study is a randomized, double-blind, placebocontrolled, event-driven study evaluating the efficacy and safety of ralinepag in subjects with PAH. In this event-driven, Phase 3 study, approximately 700 subjects with PAH treated with standard of care are randomly assigned (1:1) to receive ralinepag or placebo. Dosing is individualized and titrated based on tolerability and clinical response. The primary objective is to assess the effect of ralinepag on the time to first adjudicated clinical worsening event;a composite endpoint including death, hospitalization due to worsening of PAH, initiation of inhaled or infused prostacyclins, disease progression, or unsatisfactory long-term response. Additional secondary assessments during the study include changes from Baseline to Week 28 in N-terminal pro-brain natriuretic peptide (NT-proBNP), 6-minute walk distance (6MWD), WHO/New York Heart Association (NYHA) Functional Class, and health-related quality of life measures. Exploratory assessments will evaluate biomarkers and pharmacogenetics. Subject safety is evaluated by capturing adverse events, hospitalizations, clinical laboratory, and ECG parameters. Subjects who experience a clinical worsening event or are participating at study closure are eligible to enter an open-label extension study (ROR-PH-303 [NCT03683186]). Long-term survival will be followed for all subjects until study closure. RESULTS: Enrollment is ongoing at approximately 200 sites in 33 countries following implementation of risk mitigation steps related to the Covid-19 pandemic. Enrollment will continue until 228 adjudicated clinical worsening events have occurred. The interim assessment includes 281 subjects randomized in 29 different countries;97% of participants have completed 28 weeks of treatment. The majority of subjects were female (79.4%) with a median age of 48.0 years, were receiving dual background therapy (82.9%), and were classified as Functional Class II (59.3%). Overall, 48 clinical worsening events have been reported at the time of the interim assessment. Of these, 34 subjects elected to continue treatment in the open-label extension study. An independent Data Monitoring Committee reviewed safety data after 50, 100, and 250 subjects were randomized and recommended study continuation without modification. CONCLUSIONS: ADVANCE OUTCOMES will assess whether ralinepag can improve function, delay disease progression, and prolong survival in subjects with PAH.

The existence of flight-to-quality under extreme conditions: Evidence from a nonlinear perspective in Chinese stocks and bonds' sectors

The COVID-19 pandemic has showed that distress to the financial system is always accompanied with the interconnection between the stock and bond markets. However, limited studies have identified the flight-toquality effect between these two markets from a nonlinear extreme perspective. Thus, using the multi-quantile VaR Granger causality test that measures the non-linearity of extreme risk, we investigated this effect in Chinese sectors via extreme risk spillover networks. Based on the findings, defensive (offensive) sectors are dominant in the stock market when facing upside (downside) risk to avoid potential investment losses. The results also confirm the robustness of the conclusion that the investment function of the financial markets weakened during the financial crisis. Moreover, compared to the Financial Bond and Enterprise Bond, the Government Bond is likely to show better risk hedging effect in cross-market risk spillover networks due to its high information transparency.

Observed coupling between air mass history, secondary growth of nucleation mode particles and aerosol pollution levels in Beijing.

Atmospheric aerosols have significant effects on the climate and on human health. New particle formation (NPF) is globally an important source of aerosols but its relevance especially towards aerosol mass loadings in highly polluted regions is still controversial. In addition, uncertainties remain regarding the processes leading to severe pollution episodes, concerning e.g. the role of atmospheric transport. In this study, we utilize air mass history analysis in combination with different fields related to the intensity of anthropogenic emissions in order to calculate air mass exposure to anthropogenic emissions (AME) prior to their arrival at Beijing, China. The AME is used as a semi-quantitative metric for describing the effect of air mass history on the potential for aerosol formation. We show that NPF events occur in clean air masses, described by low AME. However, increasing AME seems to be required for substantial growth of nucleation mode (diameter < 30 nm) particles, originating either from NPF or direct emissions, into larger mass-relevant sizes. This finding assists in establishing and understanding the connection between small nucleation mode particles, secondary aerosol formation and the development of pollution episodes. We further use the AME, in combination with basic meteorological variables, for developing a simple and easy-to-apply regression model to predict aerosol volume and mass concentrations. Since the model directly only accounts for changes in meteorological conditions, it can also be used to estimate the influence of emission changes on pollution levels. We apply the developed model to briefly investigate the effects of the COVID-19 lockdown on PM2.5 concentrations in Beijing. While no clear influence directly attributable to the lockdown measures is found, the results are in line with other studies utilizing more widely applied approaches.

Observed coupling between air mass history, secondary growth of nucleation mode particles and aerosol pollution levels in Beijing† † Electronic supplementary information (ESI) available. See DOI: 10.1039/d1ea00089f

Atmospheric aerosols have significant effects on the climate and on human health. New particle formation (NPF) is globally an important source of aerosols but its relevance especially towards aerosol mass loadings in highly polluted regions is still controversial. In addition, uncertainties remain regarding the processes leading to severe pollution episodes, concerning e.g. the role of atmospheric transport. In this study, we utilize air mass history analysis in combination with different fields related to the intensity of anthropogenic emissions in order to calculate air mass exposure to anthropogenic emissions (AME) prior to their arrival at Beijing, China. The AME is used as a semi-quantitative metric for describing the effect of air mass history on the potential for aerosol formation. We show that NPF events occur in clean air masses, described by low AME. However, increasing AME seems to be required for substantial growth of nucleation mode (diameter < 30 nm) particles, originating either from NPF or direct emissions, into larger mass-relevant sizes. This finding assists in establishing and understanding the connection between small nucleation mode particles, secondary aerosol formation and the development of pollution episodes. We further use the AME, in combination with basic meteorological variables, for developing a simple and easy-to-apply regression model to predict aerosol volume and mass concentrations. Since the model directly only accounts for changes in meteorological conditions, it can also be used to estimate the influence of emission changes on pollution levels. We apply the developed model to briefly investigate the effects of the COVID-19 lockdown on PM2.5 concentrations in Beijing. While no clear influence directly attributable to the lockdown measures is found, the results are in line with other studies utilizing more widely applied approaches. Growth of nucleation mode particles, modulated by air mass exposure to anthropogenic emissions, plays an important role in pollution development.

[Male fertility in the context of COVID-19: Concern and considerations]

Since the outbreak of coronavirus disease 2019 (COVID-19), more than 130,000 people worldwide have been infected. Many studies show that the testis is one of the organs with a high expression of angiotensin-converting enzyme 2 (ACE2), the receptor/binding protein of SARS-CoV-2, which has aroused public concerns about the possible damage to male fertility. This article presents a review and analysis of the existing literature, aiming to achieve an objective understanding of the significance of the ACE2 expression in the testis. Hitherto, clinical and laboratory data available on COVID-19 are not sufficient to provide any direct evidence that the testis is a target organ of the virus. Whether the coronavirus damages fertility in male patients with COVID-19 requires further investigation. In the absence of sufficient research-based evidence, damage of the virus to male fertility should not be over-interpreted.

Special issue: the global battle against SARS-CoV-2 and COVID-19 (Special Issue: The global battle against SARS-CoV-2 and COVID-19)

This special issue contains 11 articles which share the understanding of SARS-CoV-2 and COVID-19 from different angles, such as the key events occurred during the early outbreak, basic characteristics of the pathogen, signs and symptoms of the infected patients, possible transmission pathways of the virus, understanding on the origin and evolution of the virus, as well as the chemotherapeutic options under development, the zoonotic origins and interspecies transmission, the evaluation of SARS-CoV-2 RNA shedding in clinical specimens, presentation of clinical evidence showing the beneficial effect of traditional Chinese medicine (TCM) in the treatment of the patients, the usage of therapeutic neutralizing antibodies (NAbs) to control the spread and re-emergence of SARS-CoV-2, the implication of the endocytic pathway and autophagy in viral infection, the increasing infection rate among health workers in China, concluding with a comprehensive review on what has been learned so far about the epidemiology, etiology, virology, diagnosis, treatment, prognosis, and prevention of the disease in comparison with SARS and MERS.

Preliminary study of serum 2019-nCoV IgM and IgG antibodies in the diagnosis of COVID-19

Objective: To analyze the clinical value of serum 2019 novel coronavirus (2019-nCoV) immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in the diagnosis of COVID-19. Methods: A total of 116 patients diagnosed with NCP in the First Affiliated Hospital of Hunan University of Chinese Medicine and the First Affiliated Hospital of Xiamen University were enrolled from January to February 2020 as the disease group. A total of 134 cases, including 84 non-NCP inpatients and 50 healthy individuals served as the control group. Serum samples from all subjects were collected. A fully-automated chemiluminescence immunoassay analyzer was used to detect the concentration of 2019-nCoV IgM and IgG antibodies in serum. The sensitivity and specificity of the 2019-nCoV IgM and IgG antibody single test and combined detection were compared using the χ2 test. χ2 test and Wilcoxon's rank sum test were used to compare the positive rates and concentrations of IgM and IgG antibodies in NCP patients before and after their 2019-nCoV nucleic acid tests turning negative, respectively. The change trend of 2019-nCoV antibody concentration in the process of NCP patients was analyzed by Wilcoxon's rank sum test. Results: The sensitivity of 2019-nCoV IgG (90.5%, 105/116) was higher than that of 2019-nCoV IgM (75.9%, 88/116), the difference was statistically significant (χ2=8.91, P<0.05);The specificity of 2019-nCoV IgG (99.3%,133/134) was higher than that of 2019-nCoV IgM (94.0%, 126/134), the difference was statistically significant (χ2=5.63,P<0.05). The sensitivity (89.7%,87/97) of 2019-nCoV IgM combined with IgG was higher than that of 2019-nCoV IgM, the difference was statistically significant (χ2=6.89,P<0.05). The specificity (100%, 125/125) of 2019-nCoV IgM combined with IgG was higher than that of 2019-nCoV IgM, the difference was statistically significant (χ2=7.70, P<0.05). After 2019-nCoV nucleic acid test converted to negative, the positive rate (9/17) and concentration [13.0 (4.9, 24.7) AU/ml] of serum 2019-nCoV IgM antibody were significantly lower than those when the nucleic acid test was positive, positive rate (15/17) and concentration [29.5 (14.0, 61.3) AU/ml], respectively (χ2=5.10, Z=-3.195, both P<0.05). In the course of NCP, patients' serum samples were collected from the first day of diagnosis to every three days, three times in total. The first 2019-nCoV IgM and IgG antibody concentrations [19.4 (12.4, 63.7) AU/ml, 105.8 (74.8, 126.1) AU/ml, respectively] were significantly higher than the second concentrations [15.8 (7.1, 40.3)AU/ml, 80.5 (66.7, 105.9) AU/ml], Z were-2.897,-3.179, both P<0.05. Conclusions: 2019-nCoV IgG antibody has a good application value in the diagnosis of NCP. The concentration of 2019-nCoV IgM antibody has a certain correlation with the detection of 2019-nCoV nucleic acid. The combination of 2019-nCoV IgM and IgG antibodies with 2019-nCoV nucleic acid test may be the best laboratory index for the diagnosis of NCP at present.