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The COVID-19 pandemic has now become very severe as never before due to the overwhelming spread of Omicron. We found that Omicron outbreak can be effectively prevented by inactivated vaccines, which averted an outbreak of more than 1.6 million people in Hangzhou, China. The 36 mutations in the target spike protein of Omicron neutralizing antibody enable it to evade the immune protection afforded by vaccines. This is because that mRNA and adenovirus-vector vaccines are designed to recognize the spike (S) glycoprotein of the SARS-CoV-2 wild-type (WT) strain. However, Inactivated vaccines contain the whole viral antigens and remain stable in their recognition of newly emerging variants of SARS-CoV-2. Our study confirmed the advantage of inactivated vaccines in the face of highly mutated Omicron variant and provided a basis for the development of effective vaccines to prevent future long-term transmission, mutation and recurrence of SARS-CoV-2.

Crowd gatherings are an important cause of COVID-19 outbreaks. However, how the scale, scene and other factors of gatherings affect the spread of the epidemic remains unclear. A total of 184 gathering events worldwide were collected to construct a database, and 99 of them with a clear gathering scale were used for statistical analysis of the impact of these factors on the disease incidence among the crowd in the study. The results showed that the impact of small-scale (less than 100 people) gathering events on the spread of COVID-19 in the city is also not to be underestimated due to their characteristics of more frequent occurrence and less detection and control. In our dataset, 22.22% of small-scale events have an incidence of more than 0.8. In contrast, the incidence of most large-scale events is less than 0.4. Gathering scenes such as "Meal" and "Family" occur in densely populated private or small public places have the highest incidence. We further designed a model of epidemic transmission triggered by crowd gathering events and simulated the impact of crowd gathering events on the overall epidemic situation in the city. The simulation results showed that the number of patients will be drastically reduced if the scale and the density of crowds gathering are halved. It indicated that crowd gatherings should be strictly controlled on a small scale. In addition, it showed that the model well reproduce the epidemic spread after crowd gathering events better than does the original SIER model and could be applied to epidemic prediction after sudden gathering events.

The evolution of the COVID-19 pandemic features the alternation of oscillations and abrupt rises. The oscillations are attributable to weekly and seasonal modulations, while abrupt rises are stimulated by mass gatherings.

The carbon dioxide (CO2) is notorious as the greenhouse gas, which could cause the global warming and climate change. Therefore, the reduction of the atmospheric CO2 emissions from power plants and other industrial facilities has become as an increasingly urgent concern. In the recent years, CO2 capture and storage technologies have received a worldwide attention. Adsorption is considered as one of the efficient options for CO2 capture because of its cost advantage, low energy requirement and extensive applicability over a relatively wide range of temperature and pressure. The metal organic frameworks (MOFs) show widely potential application prospects in CO2 capture and storage owing to their outstanding textural properties, such as the extraordinarily high specific surface area, tunable pore size, ultrahigh porosity (up to 90%), high crystallinity, adjustable internal surface properties, and controllable structure. Herein, the most important research progress of MOFs materials on the CO2 capture and storage in recent years has been comprehensively reviewed. The extraordinary characteristics and CO2 capture performance of Zeolitic Imidazolate Frameworks (ZIFs), Bio-metal organic frameworks (bio-MOFs), IL@MOFs and MOF-composite materials were highlighted. The promising strategies for improving the CO2 adsorption properties of MOFs materials, especially the low-pressure adsorption performance under actual flue gas conditions, are also carefully summarized. Besides, CO2 is considered as an abundant, nontoxic, nonflammable, and renewable C1 resource for the synthesis of useful chemicals and fuels. The potential routes for resource utilization of the captured CO2 are briefly proposed.

Estimating the impacts on PM估算不同城市区域人类活动对 PM2.5 污染和 CO2 排放的影响对于制定有效的政策非常重要。 2020 年初,中国实施了封城措施以遏制 COVID-19 的传播,这使得人类活动大幅减少。这为研究交通和工业部门的人类活动对空气污染的影响提供了一个有利的机会。在此,我们结合环境和气象观测数据集,即Suomi-NPP/VIIRS (Visible Infrared Imaging Radiometer Suite)和碳监测项目的CO2排放数据集,研究了中国特大城市因COVID-19封锁政策而导致的空气质量变化。我们的研究表明,由于交通大幅下降和制造业的严重停工,2020 年春季长三角(YRD)和珠三角(PRD)的 PM2.5 浓度分别下降了 41.87% 和 43.30%。然而,由于能源和钢铁行业没有完全停工,京津冀(BTH)地区PM2.5浓度仅下降了2.01%。此外,不利的天气条件导致京津冀的PM2.5 浓度进一步上升。此外,尽管与 2019 年同期相比,中国的二氧化碳排放量减少了 19.52%,但在短期减排期间,中国的二氧化碳浓度并未受到显着影响。我们的研究结果表明,不同排放部门的共同努力和有效的长期减排战略对于控制空气污染和CO2排放是必要的。.

A series of strict lockdown measures were implemented in the areas of China worst affected by coronavirus disease 19, including Wuhan, to prevent the disease spreading. The lockdown had a substantial environmental impact, because traffic pollution and industrial emissions are important factors affecting air quality and public health in the region. After the lockdown, the average monthly air quality index (AQI) in Wuhan was 59.7, which is 33.9% lower than that before the lockdown (January 23, 2020) and 47.5% lower than that during the corresponding period (113.6) from 2015 to 2019. Compared with the conditions before the lockdown, fine particulate matter (PM2.5) decreased by 36.9% and remained the main pollutant. Nitrogen dioxide (NO2) showed the largest decrease of approximately 53.3%, and ozone (O3) increased by 116.6%. The proportions of fixed-source emissions and transported external-source emissions in this area increased. After the lockdown, O3 pollution was highly negatively correlated with the NO2 concentration, and the radiation increase caused by the PM2.5 reduction was not the main reason for the increase in O3. This indicates that the generation of secondary pollutants is influenced by multiple factors and is not only governed by emission reduction., Graphical abstract Unlabelled Image, Highlights • The AQI of Wuhan City decreased significantly, the higher the population density, the more significant the decline. • NO2 decreased most in Wuhan, but O3 increased significantly, and Hubei Province also had the same trend. • The mobile source emission ratio and the local pollution contribution in Wuhan decreased.

A novel coronavirus (COVID‐19) has caused viral pneumonia worldwide, posing a major threat to international health. Our study reports that city lockdown is an effective way to reduce the number of new cases and the nitrogen dioxide (NO2) concentration can be used as an environmental lockdown indicator to evaluate the effectiveness of lockdown measures. The airborne NO2 concentration steeply decreased over the vast majority of COVID‐19‐hit areas since the lockdown. The total number of newly confirmed cases reached an inflection point about two weeks since the lockdown and could be reduced by about 50% within 30 days of the lockdown. The stricter lockdown will help newly confirmed cases to decline earlier and more rapidly, and at the same time, the reduction rate of NO2 concentration will increase. Our research results show that NO2 satellite observations can help decision makers effectively monitor and manage non‐pharmaceutical interventions in the epidemic., Key Points The global airborne NO2 concentration steeply decreased over the vast majority of COVID‐19‐hit areasThe total number of newly confirmed cases reached an inflection point about two weeks after the lockdownNO2 satellite measurement can be adopted as an environmental lockdown indicator

COVID-19 is now in an epidemic phase, with a second outbreak likely to appear at any time. The intensity and timing of a second outbreak is a common concern worldwide. In this study, we made scenario projections of the potential second outbreak of COVID-19 using a statistical-epidemiology model, which considers both the impact of seasonal changes in meteorological elements and human social behaviors such as protests and city unblocking. Recent street protests in the United States and other countries are identified as a hidden trigger and amplifier of the second outbreak. The scale and intensity of subsequent COVID-19 outbreaks in the U.S. cities where the epidemic is under initial control are projected to be much greater than those of the first outbreak. For countries without reported protests, lifting the COVID-19 related restrictions prematurely would accelerate the spread of the disease and place mounting pressure on the local medical system that is already overloaded. We anticipate these projections will support public health planning and policymaking by governments and international organizations.

Recently, a novel coronavirus (COVID-19) has caused viral pneumonia worldwide, spreading to more than 200 countries, posing a major threat to international health. To prevent the spread of COVID-19, in this study, we report that the city lockdown measure was an effective way to reduce the number of new cases, and the nitrogen dioxide (NO2) concentration can be adopted as an environmental lockdown indicator. In China, after strict city lockdown, the average NO2concentration decreased 55.7% (95% confidence interval (CI): 51.5-59.6%) and the total number of newly confirmed cases decreased significantly. Our results also indicate that the global airborne NO2concentration steeply decreased over the vast majority of COVID-19-hit areas based on satellite measurements. We found that the total number of newly confirmed cases reached an inflection point about two weeks after the lockdown. The total number of newly confirmed cases can be reduced by about 50% within 30 days of the lockdown. The stricter lockdown will help newly confirmed cases to decline earlier and more rapidly. Italy, Germany and France are good examples. Our results suggest that NO2satellite measurement can help decision makers effectively monitor control regulations to reduce the spread of COVID-19.

The interfacial effect between different metallic active centers can greatly influence their synergistic effect, further affecting their catalytic performance. Therefore, Co–Ni bimetal based ordered mesoporous metal oxide catalysts with different interfacial properties have been prepared by a one-pot evaporation induced self-assembly (EISA) strategy as well as an incipient impregnation method. The obtained catalysts with large specific surface areas, large pore volumes, and narrow pore size distributions were investigated as catalysts toward CO2 methanation. It was found that the Co–Ni bimetal catalyst synthesized by the one-pot EISA strategy displayed a much higher catalytic activity in CO2 conversion than the counterparts prepared by the incipient impregnation method, especially in a low reaction temperature region. The reason for this could be attributed to the difference in their interfacial properties based on XPS and H2-TPR characterization studies, which greatly affected the catalytic activities. Besides, all the investigated catalysts showed excellent catalytic stabilities without deactivation after 50 h time on stream owing to the confinement effect of the mesoporous framework and mesoporous channel, which could effectively suppress the thermal sintering of the metallic active centers. Therefore, the Co–Ni based bimetal ordered mesoporous catalysts constructed by the one-pot EISA strategy could be considered as a potential efficient catalyst candidate for CO2 methanation.

A series of mesoporous nanocrystalline Ce–Zr solid solutions with different Ce/Zr ratios were successfully synthesized by the evaporation-induced self-assembly strategy, and were employed as catalytic supports of CuO-based catalysts for CO oxidation. These supports and catalysts were systematically characterized by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2-TPR), CO2 temperature programmed desorption (CO2-TPD), etc. The catalytic performances toward CO oxidation had been carefully evaluated over these CuO-based catalysts. The effects of various influencing factors, such as the Ce/Zr ratio, mesostructure, redox properties of the support, CuO loading amount and calcination temperature, on the low-temperature catalytic activity had been carefully investigated. The results showed that the catalyst supported on the support with a Ce/Zr ratio of 80/20 exhibited the highest catalytic activity. It was also found that the Ce–Zr solid solution mesoporous catalysts exhibited much higher catalytic activity than the counterparts without evident mesostructure, demonstrating the advantages of the mesoporous catalysts by providing more accessible catalytically active sites. Besides, the mesoporous Ce–Zr solid solution-supported catalysts with excellent redox properties displayed much better catalytic performances than the commercial γ-Al2O3-supported catalyst. The kinetic study also indicated that the apparent activation energy of the CO oxidation process was greatly affected by the Ce/Zr ratio, mesostructure, and redox properties of the support. Overall, the present CuO-based catalysts with mesoporous nanocrystalline Ce–Zr solid solutions as supports were considered as a series of promising catalysts for CO oxidation.

The Ni based catalysts have been considered as potential candidates for the CO2 methanation owing to the low cost. However, the poor low-temperature catalytic activities limit their large-scale industrial application. In order to address this challenge, a series of Co Ni bimetal doped ordered mesoporous Al2O3 materials have been designed and fabricated via the one-pot evaporation induced self-assembly strategy and employed as the catalysts for CO2 methanation. It is found that the large specific surface areas (up to 260.0 m2/g), big pore volumes (up to 0.59 cm3/g), and narrow pore size distributions of these catalysts have been successfully retained after 700 °C calcination. The Co and Ni species are homogenously distributed among the Al2O3 matrix due to the unique advantage of the one-pot synthesis strategy. The strong interaction between metal and mesoporous framework have been formed and the severely thermal sintering of the metallic Co Ni active centers can be successfully inhibited during the processes of catalyst reduction and 50 h CO2 methanation reaction. More importantly, the synergistic effect between Co and Ni can greatly enhance the low-temperature catalytic activity by coordinating the activation of H2 and CO2, prominently decreasing the activation energy toward CO2 methanation. As a result, their low-temperature activities are evidently promoted. Furthermore, the effect of the Co/(Co + Ni) molar percentage ratio on the catalytic property has been also systematically investigated over these catalysts. It is found that only the catalyst with appropriate ratio (20.0%) behaves the optimum catalytic performances. Therefore, the current Co Ni based ordered mesoporous materials promise potential catalysts for CO2 methanation.

Ni is usually used as the catalyst for the CO2 methanation to generate the substitute natural gas (SNG) due to the low cost. However, it often possesses relatively worse low-temperature catalytic activity than the noble metal counterparts. In order to solve this problem, a series of Ca doped Ni based ordered mesoporous materials had been facilely fabricated via the one-pot evaporation induced self-assembly (EISA) strategy and directly used as the catalysts for CO2 methanation. These materials had been systematically characterized by XRD, N2 adsorption-desorption, TEM, SAED, EDS, XPS, H2-TPR, and CO2-TPD measurements. It was discovered that the large specific surface areas (210.7–240.7 m2/g), big pore volumes (0.37–0.46 cm3/g), and narrow pore size distributions (8.3–9.5 nm) of these materials had been successfully retained after 700 °C calcination. In these materials, Ni species were homogenously dispersed among the Al2O3 matrix via the one-pot fabrication strategy and the strong interaction between Ni and mesoporous framework had been formed. Thus, the seriously thermal sintering of the metallic Ni nanoparticles could be successfully inhibited. Hence, they displayed no deactivation after 50 h stability test toward CO2 methanation. More importantly, the doping of the Ca greatly enhanced the surface basicity, which could favor the chemisorption and activation of CO2. As a result, the apparent activation energies of CO2 could be remarkably decreased from 75.2 to 53.6 kJ/mol and the low-temperature catalytic activity had been significantly promoted. Therefore, these Ca doped Ni based ordered mesoporous materials promised potential catalysts for CO2 methanation.

Ni based catalysts are usually used for catalyzing the CO 2 methanation to produce synthetic natural gas due to their low cost, though their catalytic activities cannot be comparable with the noble metal counterparts. In order to address this challenge, a series of rare earth (La, Ce, Sm, and Pr) doped Ni based mesoporous materials had been facilely fabricated by the one-pot evaporation induced self-assembly (EISA) strategy and directly employed as the catalysts for CO 2 methanation. These mesoporous catalysts had been systematically characterized by means of X-ray diffraction, N 2 physisorption, transmission electron microscope, X-ray photoelectron spectroscopy, H 2 temperature programmed reduction, CO 2 temperature programmed desorption, and so on. It was found that the Ni species were highly dispersed among the mesoporous framework and the strong metal-framework interaction had been formed. Thus, the thermal sintering of the metallic Ni nanoparticles could be effectively suppressed under CO 2 methanation conditions, promising these mesoporous catalysts with 50 h excellent catalytic stabilities without evident deactivation. Besides, the rare earth dopants could greatly increase the surface basicity of the catalysts and intensify the chemisorption the CO 2 . Further, the rare earth elements were also functioned as the electron modifiers, which was also helpful in activating the CO 2 molecule. The apparent activation energies of CO 2 could be obviously decreased by rare earth dopants. As a result, their low-temperature catalytic activity had been greatly intensified over these rare earth elements promoted catalysts.

CuO-based catalysts are usually used for CO oxidation owing to their low cost and excellent catalytic activities. In this study, a series of metal oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2)-doped CuO-based catalysts with mesoporous Ce0.8Zr0.2O2 support were simply prepared by the incipient impregnation method and used directly as catalysts for CO catalytic oxidation. These mesoporous catalysts were systematically characterized by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and H2 temperature programmed reduction (H2-TPR). It was found that the CuO and the dopants were highly dispersed among the mesoporous framework via the incipient impregnation method, and the strong metal framework interaction had been formed. The effects of the types of the dopants and the loading amounts of the dopants on the low-temperature catalytic performances were carefully studied. It was concluded that doped transition metal oxides could regulate the oxygen mobility and reduction ability of catalysts, further improving the catalytic activity. It was also found that the high dispersion of rare earth metal oxides (PrO2, Sm2O3) was able to prevent the thermal sintering and aggregation of CuO-based catalysts during the process of calcination. In addition, their presence also evidently improved the reducibility and significantly reduced the particle size of the CuO active sites for CO oxidation. The results demonstrated that the 15CuO-3Fe2O3/M-Ce80Zr20 catalyst with 3 wt. % of Fe2O3 showed the best low-temperature catalytic activity toward CO oxidation. Overall, the present Fe2O3-doped CuO-based catalysts with mesoporous nanocrystalline Ce0.8Zr0.2O2 solid solution as support were considered a promising series of catalysts for low-temperature CO oxidation.

At the time of writing, coronavirus disease 2019 (COVID-19) is seriously threatening human lives and health throughout the world. Many epidemic models have been developed to provide references for decision-making by governments and the World Health Organization. To capture and understand the characteristics of the epidemic trend, parameter optimization algorithms are needed to obtain model parameters. In this study, the authors propose using the Levenberg–Marquardt algorithm (LMA) to identify epidemic models. This algorithm combines the advantage of the Gauss–Newton method and gradient descent method and has improved the stability of parameters. The authors selected four countries with relatively high numbers of confirmed cases to verify the advantages of the Levenberg–Marquardt algorithm over the traditional epidemiological model method. The results show that the Statistical-SIR (Statistical-Susceptible–Infected–Recovered) model using LMA can fit the actual curve of the epidemic well, while the epidemic simulation of the traditional model evolves too fast and the peak value is too high to reflect the real situation. 摘要 现如今, 新冠肺炎(COVID-19)严重威胁着世界各国人民的生命健康.许多流行病学模型已经被用于为政策制定者和世界卫生组织提供决策参考.为了更加深刻的理解疫情趋势的变化特征, 许多参数优化算法被用于反演模型参数.本文提议使用结合了高斯-牛顿法和梯度下降法的Levenberg–Marquardt(LMA)算法来优化模型参数.使用四个病例数相对较多的国家来验证这一算法的优势:相较于传统流行病学模型模拟曲线过早过快的到达峰值, 应用LMA的Statistical-SIR(Statistical-Susceptible–Infected–Recovered)模型可以更好地拟合实际疫情曲线., Graphical abstract Image, graphical abstract

For CO2 methanation reaction, a Mg species is often utilized as the alkaline promotor for Ni based catalysts to enhance the low-temperature catalytic activity. Herein, based on a pioneer ordered mesoporous NiO–Al2O3 catalyst, a Mg alkaline promotor had been incorporated into the ordered mesoporous framework via a one-pot evaporation induced self-assembly (EISA) strategy. As a result, the ordered mesoporous NiO–MgO–Al2O3 composite oxides with Mg/Al molar ratios in a wide range (0–10%) were successfully fabricated and directly utilized as the catalysts for CO2 methanation reaction. These mesoporous catalysts were carefully characterized by X-ray diffraction, N2 adsorption–desorption, transmission electron microscopy, selected area electron diffraction, energy dispersive spectrometer, X-ray photoelectron spectroscopy, H2 temperature-programmed reduction, and CO2 temperature-programmed desorption measurements. It was found that the ordered mesoporous materials with large specific surface areas (180.8–232.8 m2 g−1), big pore volumes (0.37–0.43 cm3 g−1), and narrow pore size distributions (around 9.5 nm) could be successfully retained after the calcination at 700 °C. The highly dispersed Ni species were strongly interacted with the mesoporous framework in the form of NiAl2O4 spinel. The incorporation of the Mg progressively increased the surface basicity of these catalysts, which could intensify the chemisorption and activation of CO2 during the CO2 methanation reaction. Therefore, the low-temperature catalytic activity was significantly enhanced. The “volcano-shape curve” relationship between the Mg/Al molar ratio and catalytic activity had been interestingly observed, suggesting only appropriate surface basicity could obtain the optimum catalytic activity. Besides, there was no evident deactivation over these mesoporous catalysts after 50 h long-term stability tests due to the confinement effect of the mesoporous framework. Therefore, the present ordered mesoporous NiO–MgO–Al2O3 materials could be considered as a series of potential catalyst candidates for CO2 methanation.

In the past two decades, great progress has been made in the aspects of fabrication and application of ordered mesoporous metal oxides. Ordered mesoporous metal oxides have attracted more and more attention due to their large surface areas and pore volumes, unblocked pore structure, and good thermal stabilities. Compared with non-porous metal oxides, the most prominent feature is their ability to interact with molecules not only on their outer surface but also on the large internal surfaces of the material, providing more accessible active sites for the reactants. This review carefully describes the characteristics, classification and synthesis of ordered mesoporous metal oxides in detail. Besides, it also summarizes the catalytic application of ordered mesoporous metal oxides in the field of carbon dioxide conversion and resource utilization, which provides prospective viewpoints to reduce the emission of greenhouse gas and the inhibition of global warming. Although the scope of current review is mainly limited to the ordered mesoporous metal oxides and their application in the field of CO2 catalytic conversion via heterogeneous catalysis processes, we believe that it will provide new insights and viewpoints to the further development of heterogeneous catalytic materials.

CuO-based catalysts are usually used for CO oxidation owing to their low cost and excellent catalytic activities. In this study, a series of metal oxide (La2O3, Fe2O3, PrO2, Sm2O3, and MnO2)-doped CuO-based catalysts with mesoporous Ce0.8Zr0.2O2 support were simply prepared by the incipient impregnation method and used directly as catalysts for CO catalytic oxidation. These mesoporous catalysts were systematically characterized by X-ray powder diffraction (XRD), N2 physisorption, transmission electron microscopy (TEM), energy-dispersed spectroscopy (EDS) mapping, X-ray photoelectron spectroscopy (XPS), and H2 temperature programmed reduction (H2-TPR). It was found that the CuO and the dopants were highly dispersed among the mesoporous framework via the incipient impregnation method, and the strong metal framework interaction had been formed. The effects of the types of the dopants and the loading amounts of the dopants on the low-temperature catalytic performances were carefully studied. It was concluded that doped transition metal oxides could regulate the oxygen mobility and reduction ability of catalysts, further improving the catalytic activity. It was also found that the high dispersion of rare earth metal oxides (PrO2, Sm2O3) was able to prevent the thermal sintering and aggregation of CuO-based catalysts during the process of calcination. In addition, their presence also evidently improved the reducibility and significantly reduced the particle size of the CuO active sites for CO oxidation. The results demonstrated that the 15CuO-3Fe2O3/M-Ce80Zr20 catalyst with 3 wt. % of Fe2O3 showed the best low-temperature catalytic activity toward CO oxidation. Overall, the present Fe2O3-doped CuO-based catalysts with mesoporous nanocrystalline Ce0.8Zr0.2O2 solid solution as support were considered a promising series of catalysts for low-temperature CO oxidation.

In the past two decades, great progress has been made in the aspects of fabrication and application of ordered mesoporous metal oxides. Ordered mesoporous metal oxides have attracted more and more attention due to their large surface areas and pore volumes, unblocked pore structure, and good thermal stabilities. Compared with non-porous metal oxides, the most prominent feature is their ability to interact with molecules not only on their outer surface but also on the large internal surfaces of the material, providing more accessible active sites for the reactants. This review carefully describes the characteristics, classification and synthesis of ordered mesoporous metal oxides in detail. Besides, it also summarizes the catalytic application of ordered mesoporous metal oxides in the field of carbon dioxide conversion and resource utilization, which provides prospective viewpoints to reduce the emission of greenhouse gas and the inhibition of global warming. Although the scope of current review is mainly limited to the ordered mesoporous metal oxides and their application in the field of CO2 catalytic conversion via heterogeneous catalysis processes, we believe that it will provide new insights and viewpoints to the further development of heterogeneous catalytic materials.