The whole world has entered a terrible crisis with a huge and increasing number of human deaths and economic losses in fighting the pandemic of COVID‐19 caused by the novel coronavirus termed ...SARS‐CoV‐2. The live pathogen vaccine (LPV) strategy, which originated in ancient China for fighting smallpox, has been applied successfully by US military recruits for decades to control acute respiratory diseases caused by types 4 and 7 adenoviruses. This strategy has also been widely employed in veterinary medicine. These facts suggest a fast way out of the current pandemic crisis, namely that SARS‐CoV‐2 could be directly used as a live vaccine. Beyond the two traditional mechanisms to guarantee the LPV's safety (the LPV seed strain is properly selected; the LPV is inoculated bypassing the respiratory sites of pathology), three novel mechanisms to further ensure the LPV's safety are available (the virus replication is inhibited with early use of an antiviral drug; symptomatic LPV recipients are cured with convalescent plasma; the LPV is inoculated in the hot season). This LPV strategy has multiple potential advantages over other options and could reduce morbidity and mortality greatly as well as the economic loss caused by the pandemic. The safety and efficacy of this strategy should be investigated strictly using animal experiments and clinical trials, and even if the experiments and trials all support the strategy, it should be implemented with enough caution.
Highlights
●The world has entered a terrible crisis in fighting the COVID‐19 pandemic.
●Live pathogen vaccines (LPV) have defeated infectious diseases caused by adenoviruses.
●The LPV strategy has been widely employed in veterinary medicine.
●The LPV strategy could be a way out of the COVID‐19 pandemic crisis.
●Five mechanisms can be employed to ensure the safety of the LPV of SARS‐CoV‐2.
●The LPV strategy should be examined with animal experiments and clinical trials.
The ongoing pandemic of coronavirus disease 2019 (COVID‐19) caused by the novel virus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has claimed many lives worldwide. To combat the ...pandemic, multiple types of vaccines are under development with unprecedented rapidity. Theoretically, future vaccination against COVID‐19 may fall into long‐term costly guerrilla warfare between SARS‐CoV‐2 and humans. Elimination of SARS‐CoV‐2 through vaccination to avoid the potential long‐term costly guerrilla warfare, if possible, is highly desired and worth intensive consideration. Human influenza pandemics emerging in 1957, 1968, and 2009 established strong global herd immunity and led to the elimination of three human influenza viruses, which circulated worldwide for years before the pandemics. Moreover, both clade 7.2 of subtype H5 highly pathogenic avian influenza virus and subtype H7N9 avian influenza virus circulated in poultry in China for years, and they have been virtually eliminated through mass vaccination in recent years. These facts suggest that the rapid establishment of global herd immunity through mass vaccination using an appropriate vaccine could eliminate SARS‐CoV‐2. The coming 2 years are a golden time for elimination through vaccination, which requires tremendous national and international collaboration. This review also prioritizes the efficacy of vaccines for COVID‐19 and elucidates the importance of the development of more live vaccines for COVID‐19.
Highlights
Future vaccination against coronavirus disease 2019 (COVID‐19) may fall into long‐term costly guerrilla warfare between severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and humans.
Elimination of SARS‐CoV‐2 through vaccination is highly desired and worth intensive consideration.
Multiple influenza viruses have been eliminated through natural pandemics or mass vaccination.
The coming 2 years are a golden time for the elimination of SARS‐CoV‐2 through mass vaccination.
Rapid establishment of global herd immunity through vaccination using a live vaccine could eliminate SARS‐CoV‐2.
The coronavirus disease 2019 (COVID‐19) pandemic caused by the coronavirus severe acute respiratory syndrome coronavirus 2 remains risky worldwide. We elucidate here that good IDM (isolation, ...disinfection, and maintenance of health) is powerful to reduce COVID‐19 deaths based on the striking differences in COVID‐19 case fatality rates among various scenarios. IDM means keeping COVID‐19 cases away from each other and from other people, disinfecting their living environments, and maintaining their health through good nutrition, rest, and treatment of symptoms and pre‐existing diseases (not through specific antiviral therapy). Good IDM could reduce COVID‐19 deaths by more than 85% in 2020 and more than 99% in 2022. This is consistent with the fact that good IDM can minimize co‐infections and maintain body functions and the fact that COVID‐19 has become less pathogenic (this fact was supported with three novel data in this report). Although IDM has been frequently implemented worldwide to some degree, IDM has not been highlighted sufficiently. Good IDM is relative, nonspecific, flexible, and feasible in many countries, and can reduce deaths of some other relatively mild infectious diseases. IDM, vaccines, and antivirals aid each other to reduce COVID‐19 deaths. The IDM concept and strategy can aid people to improve their health behavior and fight against COVID‐19 and future pandemics worldwide.
Highlights
Multiple striking differences in COVID‐19 case fatality rate were calculated.
These differences support that a strategy could reduce COVID‐19 deaths by more than 85% in 2020 and more than 99% in 2022.
The strategy is based on isolation, disinfection, and health maintenance.
The strategy can reduce co‐infections and maintain body functions.
The strategy has been implemented frequently but insufficiently worldwide.
The strategy is non‐specific and can reduce deaths of other mild infectious diseases.
The rapid spread of the Delta variant suggests that SARS‐CoV‐2 will likely be rampant for months or years and could claim millions of more lives. All the known vaccines cannot well defeat SARS‐CoV‐2 ...due to their limited efficacy and production efficiency, except for the neglected live‐attenuated vaccines (LAVs), which could have a much higher efficacy and much higher production efficiency than other vaccines. LAVs, like messiahs, have defeated far more pathogenic viruses than other vaccines in history, and most current human vaccines for viral diseases are safe LAVs. LAVs can block completely infection and transmission of relevant viruses and their variants. They can hence inhibit the emergence of vaccine‐escape and virulence‐enhancing variants and protect immunologically abnormal individuals better in general. The safety of COVID‐19 LAVs, which could save millions of more lives, can be solidly guaranteed through animal experiments and clinical trials. The safety of COVID‐19 LAVs could be greatly enhanced with intramuscular or oral administration, or administration along with humanized neutralizing monoclonal antibodies. Together, extensive global collaboration, which can greatly accelerate the development of safe COVID‐19 LAVs, is imminently needed.
•A detailed summary on the advanced technologies for the separation of HREEs was proposed.•The sources, distribution, leaching, extraction and separation of HREEs were in depth discussed.•Evaluations ...of each method and essential perspectives for future researches were put forward.•Theoretical guides was provided for the recovery and preparation of high-purity HREEs.
Heavy rare earth elements (HREEs) containing Gd to Lu plus Y have a series of unique physicochemical properties which endow them critical resources in many fields such as high-tech components, green technologies and material industries. However, the huge demand of HREEs has resulted in sharply reduction of their reserves. Henceforth, it is necessary to efficiently0020separate and recover HREEs using some simple and commercially viable methods. The present review makes a detailed summary on the advanced technologies for the separation and purification of HREEs in recent ten years including both liquid-liquid extraction (LLE) and solid-liquid separation (SLP). Further understandings of the crucial scientific issues such as sources, distribution, and leaching, as well as extraction background, extraction theory, extraction technology, separation efficiency and adsorption capacity, were also in depth discussed. Evaluations of each method and essential perspectives for future researches were proposed in the end of this review. Meanwhile, this review should provide theoretical guides for the preparation of high-purity HREEs and references for the recovery of HREEs from the actual production.
Many people want to know when the COVID‐19 pandemic will end and life will return to normal. This question is highly elusive and distinct predictions have been proposed. In this study, the global ...mortality and case fatality rate of COVID‐19 were analyzed using nonlinear regression. The analysis showed that the COVID‐19 pandemic could terminate in 2022, but COVID‐19 could be one or two times more deadly than seasonal influenza by 2023. The prediction considered the possibility of the emergence of new variants of SARS‐CoV‐2 and was supported by the features of the Omicron variant and other facts. As the herd immunity against COVID‐19 established through natural infections and mass vaccination is distinct among countries, COVID‐19 could be more or less deadly in some countries in the coming years than the prediction. Although the future of COVID‐19 will have multiple possibilities, this statistics‐based prediction could aid to make proper decisions and establish an example on the prediction of infectious diseases.
Highlights
The global mortality and case fatality rate of COVID‐19 were statistically analyzed.
The analysis provided novel statistics for the prediction of the COVID‐19 pandemic.
The COVID‐19 pandemic could terminate in 2022.
COVID‐19 could be one or two times more deadly than seasonal influenza by 2023.
The surge of patients in the pandemic of COVID‐19 caused by the novel coronavirus SARS‐CoV‐2 may overwhelm the medical systems of many countries. Mask‐wearing and handwashing can slow the spread of ...the virus, but currently, masks are in shortage in many countries, and timely handwashing is often impossible. In this study, the efficacy of three types of masks and instant hand wiping was evaluated using the avian influenza virus to mock the coronavirus. Virus quantification was performed using real‐time reverse transcription‐polymerase chain reaction. Previous studies on mask‐wearing were reviewed. The results showed that instant hand wiping using a wet towel soaked in water containing 1.00% soap powder, 0.05% active chlorine, or 0.25% active chlorine from sodium hypochlorite removed 98.36%, 96.62%, and 99.98% of the virus from hands, respectively. N95 masks, medical masks, and homemade masks made of four‐layer kitchen paper and one‐layer cloth could block 99.98%, 97.14%, and 95.15% of the virus in aerosols. Medical mask‐wearing which was supported by many studies was opposed by other studies possibly due to erroneous judgment. With these data, we propose the approach of mask‐wearing plus instant hand hygiene (MIH) to slow the exponential spread of the virus. This MIH approach has been supported by the experiences of seven countries in fighting against COVID‐19. Collectively, a simple approach to slow the exponential spread of SARS‐CoV‐2 was proposed with the support of experiments, literature review, and control experiences.
Abstract
The world has experienced dramatic urbanization in recent decades. However, we still lack information about the characteristics of urbanization in large cities throughout the world. After ...analyzing 841 large cities with built-up areas (BUAs) of over 100 km
2
from 2001 to 2018, here we found an uneven distribution of urbanization at different economic levels. On average, large cities in the low-income and lower-middle-income countries had the highest urban population growth, and BUA expansion in the upper-middle-income countries was more than three times that of the high-income countries. Globally, more than 10% of BUAs in 325 large cities showed significant greening (
P
< 0.05) from 2001 to 2018. In particular, China accounted for 32% of greening BUAs in the 841 large cities, where about 108 million people lived. Our quantitative results provide information for future urban sustainable development, especially for rational urbanization of the developing world.
•Laboratory-matured shale samples were produced by an anhydrous pyrolysis experiment.•Low-pressure gas adsorption was used to characterize the pore structure of laboratory-matured shales.•There are ...substantial differences in evolution of nanoporosity between organic-rich and organic-poor samples.•Evolution of organic matter-hosted nanopores of gas shales can be roughly divided into three stages.
Artificial shale samples with equivalent vitrinite reflectance values (VRo) ranging from 0.69% to 4.19% were obtained from an anhydrous pyrolysis experiment. Microporous and mesoporous characteristics of these samples were investigated by low-pressure nitrogen and carbon dioxide adsorption techniques. The result shows that the nanoporosity (microporosity plus mesoporosity) increases with thermal maturity after the oil window stage, and this increase is attributed to the formation of porosity within organic matter and/or mineral–organic matter groundmass, rather than in the pure clay minerals. By combining the gas generation and porosity evolution of these shales, a general model for formation and development of the nanoporosity is proposed.
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