Scaling law of COVID-19 cases and city size and its evolution over time

Urban scaling law quantifies the disproportional growth of urban indicators with urban population size, which is one of the simple rules behind the complex urban system. Infectious diseases are closely related to social interactions that intensify in large cities, resulting in a faster speed of transmission in large cities. However, how this scaling relationship varies in an evolving pandemic is rarely investigated and remains unclear. Here, taking the COVID- 19 epidemic in the United States as an example, we collected daily added cases and deaths from January 2020 to June 2022 in more than three thousand counties to explore the scaling law of COVID- 19 cases and city size and its evolution over time. Results show that COVID- 19 cases super- linearly scaled with population size, which means cases increased faster than population size from a small city to a large city, resulting in a higher morbidity rate of COVID- 19 in large cities. Temporally, the scaling exponent that reflects the scaling relationship stabilized at around 1.25 after a fast increase from less than one. The scaling exponent gradually decreased until it was close to one. In comparison, deaths caused by the epidemic did not show a super-linear scaling relationship with population size, which revealed that the fatality rate of COVID-19 in large cities was not higher than that in small or medium-sized cities. The scaling exponent of COVID- 19 deaths shared a similar trend with that of COVID- 19 cases but with a lag in time. We further estimated scaling exponents in each wave of the epidemic, respectively, which experienced the common evolution process of first rising, then stabilizing, and then decreasing. We also analyzed the evolution of scaling exponents over time from regional and provincial perspectives. The northeast, where New York State is located, had the highest scaling exponent, and the scaling exponent of COVID- 19 deaths was higher than that of COVID-19 cases, which indicates that large cities in this region were more prominently affected by the epidemic. This study reveals the size effect of infectious diseases based on the urban scaling law, and the evolution process of scaling exponents over time also promotes the understanding of the urban scaling law. The mechanism behind temporal variations of scaling exponents is worthy of further exploration. © 2023 Science Press. All rights reserved.

Progress in Research of COVID-19 Based on Proteomics Techniques

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus is highly contagious and spreads rapidly, posing a serious threat to the health and safety of people around the world. Proteomics technology has the characteristics of high throughput and high sensitivity, and plays an important role in biomarker discovery, molecular mechanism research, and therapeutic target research. Proteomics technology has been widely used in the research of COVID-19. Herein, this study provides a comprehensive review of the research progress of COVID-19 based on proteomics techniques. In section 1, the genome structure of SARS-CoV-2 and the process of SARS-CoV-2 infecting host cells were summarized. In section 2, the currently commonly used mass spectrometry (MS)-based proteomics techniques including liquid chromatography (LC)-MS and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS were reviewed. In section 3, the application progress in the research of precise diagnosis, molecular mechanism and drug therapy targets of COVID-19 based proteomics technology was highlighted. Proteomics have been employed in biomedical research to uncover biomarkers associated with COVID-19, it also provides a comprehensive snapshot of virus-induced changes to the host following infection, invasion, persistence, and pathogenesis and can prime the identification of novel therapeutic targets for preventing or lessening disease severity. In section 4, the future development direction of proteomics was prospected. It's hoped that this review can help to promote the development of proteomics technology in the precise diagnosis and treatment of diseases. © 2022 Institute of Biophysics,Chinese Academy of Sciences. All rights reserved.

POCT detection device based on thermal convection fluorescence PCR amplification

This article is based on the principle of thermal convection PCR and nucleic acid fluorescence intensity detection technology. The principle of thermal convection PCR is to form a temperature difference by separately controlling the upper temperature and the bottom temperature of the reaction tube. The lower temperature liquid at the upper part has relatively high density or specific gravity, and the upper and lower liquids will produce convection, which drives the flow of molecules in the tubular chamber. The reaction solution is formed into thermal convection in the reaction test tube and subjected to different temperatures, so as to meet the required conditions for the reaction of different enzymes, and realize the pre-denaturation, annealing and extension processes in the nucleic acid PCR amplification in a short time. Nucleic acid fluorescence intensity detection technology involves embedded system design for device control and signal analysis, optical system design for optical signal filtering and collection, and differential amplifier circuit design. The embedded system design is based on the development of precise temperature control system, motion system and signal analysis system based on Stm32 single-chip microcomputer. The temperature control system includes independent temperature control to control the heaters at the bottom of the reaction tube and the top of the reaction tube respectively;the motion system includes sample switching and switching of the light source in the imaging system. The optical system design includes 540nm FAM excitation light source, 570nm CY3 excitation light source and spherical lens focusing excitation system. This device uses a photodiode to convert the optical signal into an electrical signal, and then amplifies the collected electrical signal with a two-stage operational amplifier through a two-color light differential amplifier circuit, and then uses the signal analysis system to record and display the electrical signal changes in real time, and Make a qualitative analysis. This device not only has the advantages of low cost and high sensitivity, but also solves the key problem of the long time (more than 2 hours) of the whole process of real-time fluorescent quantitative PCR in the detection of new crown nucleic acid and cannot be screened quickly on site. The PCR time of this device is from 2 The hour is reduced to 30 minutes, which is suitable for POCT inspections, and achieves rapid screening goals for crowds of people, which is conducive to responding to acute nucleic acid detection and large-scale nucleic acid detection. This device is currently used with COVID-19 detection reagents to detect new coronaviruses, and realize the detection of 20 copies of nucleic acid sensitivity within 30 minutes. Four samples can be processed in batches at a time, and the sample size for single processing can be increased appropriately according to needs. This device provides rapid and sensitive screening methods for global epidemic prevention and control, and is of great significance to improve human health. This device can also be applied to other rapid nucleic acid detection fields. With different nucleic acid detection reagents, this device can detect different gene loci, and has a broad development space and application fields. © 2023 SPIE.

Progress in Research of COVID-19 Based on Proteomics Techniques

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus is highly contagious and spreads rapidly, posing a serious threat to the health and safety of people around the world. Proteomics technology has the characteristics of high throughput and high sensitivity, and plays an important role in biomarker discovery, molecular mechanism research, and therapeutic target research. Proteomics technology has been widely used in the research of COVID-19. Herein, this study provides a comprehensive review of the research progress of COVID-19 based on proteomics techniques. In section 1, the genome structure of SARS-CoV-2 and the process of SARS-CoV-2 infecting host cells were summarized. In section 2, the currently commonly used mass spectrometry (MS) -based proteomics techniques including liquid chromatography (LC)-MS and matrix-assisted laser desorption/ionization time-of-flight (MALDITOF) MS were reviewed. In section 3, the application progress in the research of precise diagnosis, molecular mechanism and drug therapy targets of COVID-19 based proteomics technology was highlighted. Proteomics have been employed in biomedical research to uncover biomarkers associated with COVID-19, it also provides a comprehensive snapshot of virus-induced changes to the host following infection, invasion, persistence, and pathogenesis and can prime the identification of novel therapeutic targets for preventing or lessening disease severity. In section 4, the future development direction of proteomics was prospected. It's hoped that this review can help to promote the development of proteomics technology in the precise diagnosis and treatment of diseases.

Hemiconvulsion-Hemiplegia-Epilepsy Syndrome in the Setting of COVID-19 Infection and Multisystem Inflammatory Syndrome in Children

Objective: To present a case of Hemiconvulsion-Hemplegia-Epilepsy (HHE) Syndrome in a child with COVID-19 infection and Multisystem Inflammatory Syndrome in Children (MIS-C). Background: HHE Syndrome is a rare pediatric epilepsy syndrome that presents with prolonged unilateral convulsive status epilepticus in the setting of fever, followed by hemiparesis, unilateral hemispheric swelling and atrophy, and the development of epilepsy. Though it was first described over six decades ago, the pathophysiology is still poorly understood with multiple factors contributing, including hyperthermia, inflammation, and cytotoxic edema from prolonged ictal activity. Prognosis is variable, from the resolution of hemiplegia and seizures to permanent hemiparesis and refractory epilepsy. Design/Methods: This is a case report based on a chart review. Results: The patient is a 2-year-old boy with a history of one prior complex febrile seizure who presented with greater than one hour of convulsive status epilepticus in the setting of fever. The patient had a generalized tonic-clonic seizure with more prominent convulsions on the right side. The patient required intubation and was initially given multiple anti-seizure loads though continued to have persistent electrographic and electroclinical seizures. EEG showed lefthemispheric high amplitude spike/polyspike and wave discharges. The patient required continuous midazolam infusion with eventual control of seizures on levetiracetam, phenobarbital, and clobazam. The examination was notable for persistent right-sided hemiparesis with gradual improvement. MRI brain without contrast revealed T2 signal abnormality and restricted diffusion diffusely throughout the left cerebral hemisphere. Infectious workup was significant for positive COVID-19 PCR and elevated inflammatory markers, consistent with MIS-C. Conclusions: Our patient had prolonged focal convulsive status epilepticus in the setting of acute febrile illness secondary to COVID-19 and MIS-C leading to hemiparesis and diffuse left cerebral hemisphere edema on MRI brain consistent with HHE syndrome. More research is needed to elucidate further HHE syndrome's pathophysiology and assess long-term outcomes in patients with HHE syndrome.

Simulation and Optimization of Isopropanol Production by Acetone Hydrogenation Process

Isopropanol is an extremely widely used chemical product. With the outbreak of COVID-19 worldwide, the export demand of isopropanol keeps increasing, and the supply is in short supply. In order to meet the demand of isopropyl alcohol in the international market, the existing production process faces new challenges and needs to be improved and upgraded. In this design, Aspen Plus was used to simulate the existing hydrogenation process of acetone to isopropanol, and it was improved and optimized to establish an annual output of 5 kT isopropanol and a variety of by-products of different specifications. The process adopts double-effect distillation and heat pump distillation to reduce energy consumption, and a set of waste liquid recovery device is designed to effectively recover the by-products and achieve the purpose of improving economic benefits. Simulation results of Aspen Plus show that energy consumption, carbon emission, water consumption and solid waste utilization rate can be reduced by 36.73%, 40%, 45% and 80% respectively, meeting the requirements of “Made in China 2025”. © 2022 SPIE. All rights reserved.

Communicable disease transmission model for the prevention and control of COVID-19 in Wuhan City, China

Epidemic prevention and control strongly affect people's lives in cities, but existing communicable disease models cannot accurately simulate the effects of prevention and control procedures. A city simulation model for the 2019 coronavirus epidemic was developed based on an Agent model for Wuhan, China to model the epidemic transmission process. The model includes the government control measures and the hospital diagnosis and treatment levels during the epidemic with analyses of the infection rates and spatial distributions for various epidemic control measures. The model was also used to model the active anti-epidemic impact of nucleic acid testing after people returned to work. The results show that this modeling method accurately reproduces the spatio-temporal transmission characteristics of the Wuhan epidemic. Thus, this method can be used to evaluate government control measures and to implement diagnosis and treatment plans for decision-making for infectious disease prevention and control. © 2021, Tsinghua University Press. All right reserved.

Location-specific health impacts of climate change require location-specific responses

Left unmitigated, climate change poses a catastrophic risk to human health, demanding an urgent and concerted response from every country. The 2015 Lancet Commission on Health and Climate Change and The Lancet Countdown: Tracking Progress on Health and Climate Change have been initiated to map out the impacts of climate change and the necessary policy responses. To meet these challenges, Tsinghua University, partnering with the University College London and 17 Chinese and international institutions, has prepared the Chinese Lancet Countdown report, which has a national focus and builds on the work of the global Lancet Countdown: Tracking Progress on Health and Climate Change. Drawing on international methodologies and frameworks, this report aims to deepen the understanding of the links between public health and climate change at the national level and track them with 23 indicators. This work is part of the Lancet's Countdown broader efforts to develop regional expertise on this topic, and coincides with the launch of the Lancet Countdown Regional Centre in Asia, based at Tsinghua University. The data and results of this report are presented at the provincial level, where possible, to facilitate targeted response strategies for local decision-makers. Based on the data and findings of the 2020 Chinese Lancet Countdown report, five recommendations are proposed to key stakeholders in health and climate change in China: (1) Enhance inter-departmental cooperation. Climate change is a challenge that demands an integrated response from all sectors, urgently requiring substantial inter-departmental cooperation among health, environment, energy, economic, financial, and education authorities. (2) Strengthen health emergency preparedness. Knowledge and findings on current and future climate-related health threats still lack the required attention and should be fully integrated into the emergency preparedness and response system. (3) Support research and raise awareness. Additional financial support should be allocated to health and climate change research in China to enhance health system adaptation, mitigation measures, and their health benefits. At the same time, media and academia should be fully motivated to raise the public and politicians' awareness of this topic. (4) Increase climate change mitigation. Speeding up the phasing out of coal is necessary to be consistent with China's pledge to be carbon neutral by 2060 and to continue to reduce air pollution. Fossil fuel subsidies must also be phased out. (5) Ensure the recovery from COVID-19 to protect health now and in the future. China's efforts to recover from COVID-19 will shape public health for years to come. Climate change should be a priority in these interventions. © 2021, Science Press. All right reserved.

Open design and 3D printing of face shields: The case study of a UK-China initiative

At the start of the COVID-19 outbreak, many countries lacked personal protective equipment (PPE) to protect healthcare workers. To address this problem, open design and 3D printing technologies were adopted to provide much-in-need PPEs for key workers. This paper reports an initiative by designers and engineers in the UK and China. The case study approach and content analysis method were used to study the stakeholders, the design process, and other relevant issues such as regulation. Good practice and lessons were summarised, and suggestions for using distributed 3D printing to supply PPEs were made. It concludes that 3D printing has played an important role in producing PPEs when there was a shortage of supply, and distributed manufacturing has the potential to quickly respond to local small-bench production needs. In the future, clearer specification, better match of demands and supply, and quicker evaluation against relevant regulations will provide efficiency and quality assurance for 3D printed PPE supplies. © 2020 Universidade do Vale do Rio dos Sinos. All rights reserved.

Impact on China's CO2 emissions from COVID-19 pandemic

Assessing the impact of the COVID-19 pandemic on China's carbon emissions is crucial for China to lead global climate change mitigation. However, thorough quantitative analyses of the pandemic's effects on energy use and emissions are still lacking. This is largely because well-known published datasets of greenhouse gas emissions are based on annual statistics that commonly become available one or more years after they are gathered. A high temporal resolution emission dataset is critical to capture the immediate effects of an event such as the COVID-19 pandemic. Such an improved resolution might also allow policy makers to more quickly observe the effects of policies aimed at decreasing CO2 emissions, facilitating rapid adjustments. Here, based on a newly developed, near real-time global emission dataset, Carbon Monitor, we estimate China's daily energy consumption and associated CO2 emissions and use this dataset to estimate the impact of COVID-19 on CO2 emission trends. Such a near-real-time CO2 emission database based on activity data quantifies both anthropogenic CO2 emissions from fossil fuel combustion and cement production. We show that the higher-resolution emission dataset can be used to assess the impact of COVID-19 (and similar future disruptions) within a reasonable range of uncertainty. This study finds that China's CO2 emissions in the first four months of 2020 decreased by 6.9% compared to the same period in 2019, with a total emission reduction of 234.5 million tons of CO2. The provinces of Jiangsu, Hubei, and Zhejiang were most severely affected by COVID-19, accounting for 19.4%, 17.0% and 12.5% of the total reduction in CO2 emissions, respectively. The reduction of CO2 emissions from Shandong, Hebei, Anhui, Henan and Chongqing provinces is more than 10 Mt CO2, and the sum of the reduction from these five provinces accounts for 28.8% of the national total reductions. CO2 emissions in Yunnan Province, Gansu Province, Guangxi Zhuang Autonomous Region, Ningxia Hui Autonomous Region, Shaanxi Province and Xinjiang Uygur Autonomous Region increased slightly compared to the same period in 2019. In addition, COVID-19 has a little effect on CO2 emissions from Qinghai Province and Tibet Autonomous Region. This decrease in atmospheric pollutants is the largest decrease recorded and is consistent with the decrease in air pollutants observed by ground observation stations. This study finds that China's national economy has recovered rapidly. In April 2020, China's carbon emissions returned to the same level observed last year. This study predicts that China's full-year CO2 in 2020 will be 2% lower than in 2019. This will be the first time China has experienced a decline since 1997. China's carbon emissions have not rebound significantly, and the dynamic changes in China's CO2 indicate a rapid recovery of the Chinese economy. Regarding long-term trends, it is still unclear how much China's CO2 emissions will change at the end of this year and how fast the economy and industry will return to normal. With policy support, the economy will be stimulated as the pandemic fades. The IMF predicts that the global annual economic output will decrease sharply by -3.0% in 2020, which is worse than the financial crisis in 2008, based on the assumption that COVID-19 will fade globally in the second half of this year. Based on current emission dynamics, China's emission decline is estimated to be less than 5%, and the future trend will be affected by whether there will be another pandemic in the future. Current statistics are still not capable of comprehensively capturing the dynamics of CO2 emissions during the COVID-19 pandemic, and further monitoring, observation and data collection are urgently needed. © 2021, Science Press. All right reserved.

Detection of microamounts of novel coronavirus residues in environment by digital PCR

2019 novel coronaviruses (2019-nCoV) swept the world and are still at a high incidence stage. Highly sensitive and accurate nucleic acid molecular diagnostic techniques and methods have become a hot spot of global concern. 2019-nCoV is a kind of RNA virus. At present. there are many methods to detect virus RNA, including real-time fluorescence quantitative PCR (RT-PCR), colloidal gold detection. chemiluminescence detection, and so on. Colloidal gold detection and chemiluminescence detection need to use monoclonal antibodies against 2019-nCoV, but there are some problems in the preparation of 2019-nCoV monoclonal antibodies, such as long cycle, complex preparation and easy pollution. So the above two methods are not easy to be established for the detection of 2019-nCoV. The superiority of PCR technology is widely used in auxiliary medical clinical diagnosis, customs inspection and quarantine, the development of new agriculture, national defense military defense, and basic research of bioscience, and so on. However, the quantification of the target DNA fragment in RT-PCR is still relatively quantitative. Because this technique mainly depends on CT value and standard curve to quantify the target DNA in the experiment which affects the amplification efficiency of the whole system, and the sensitivity and accuracy of the reaction system are greatly affected. Because the 2019-nCoV virus is highly contagious, the detection methodology is required to be highly sensitive, which is in line with the characteristics of digital PCR (droplet digital PCR system, referred to as ddPCR). ddPCR has the advantages of absolute quantification, high specificity, high sensitivity and strong interference ability, which can better combine molecular biology and medicine closely, and has a great advantage in the detection of 2019-nCoV. In this study, based on droplet digital PCR detection technology. the detection reagent and method were established using the principle of nested PCR. The Saliva of 333 2019-nCoV patients and their environmental samples were detected and compared with real-time PCR (RT-PCR). The linear range of the droplet digital PCR method established in this study was between 25-5 copies/A, and minimum detection limit was 0.5 copies/A. which was 2-3 orders of magnitude higher than that of the commercial real-time fluorescent quantitative PCR detection technology. In 333 samples, 7 were positive in 197 environmental samples, and 9 were positive in 136 human samples. The detection accuracy was 100%, and the environmental micro-virus residues that could not be detected by RT-PCR were detected. The digital PCR detection method established in this study was highly specific, and the minimum detection limit was far lower than that of RT-PCR. It is of great significance for sensitive and accurate detection of 2019-nCoV infection. early infection and environmental microvirus.

Research on diagnostic system integrated nucleic acid extraction and detection

With the continuous impact of COVID-19, the demand for rapid genetic diagnosing at the inspection and quarantine site, emergency treatment of sudden infectious diseases and clinical in vitro diagnosis was increasing rapidly. In order to achieve rapid, automatic nucleic acid extraction and detection, an automatic diagnostic system which integrates nucleic acid extraction, amplification and biochip fluorescence detection is designed. The diagnostic system designed based on multidisciplinary intersection of biology, optoelectronics, machinery and computer technology. At first, the nucleic acid extraction part has 1-8 sample flux and uses the principle of the silicon filter can adsorb nucleic acid at different pH to achieve nucleic acid extraction. After the extraction process, the nucleic acid is injected into biochip through robotic arm. There is a specific microarray reaction chamber on the chip, which can be combined with a specific biological substance;Secondly the amplification part used the principle of flat-plate PCR to achieve nucleic acid amplification in the biochip;After amplification, the nucleic acid detection realized under the irradiation of the excitation light at 530nm, the specificity target on the biochip will emit light, thus the fluorescence image scanned by COMS camera and the result analyzed by the software on PC;At last device control, automation and detection of the integrated device realized by the STM32 single-chip microcomputer and CAN communication method to establish a device communication network. The diagnostic system will automate workflow, and provides a result that reports on the detection and interpretation of targets in the samples. The imaging module resolution was less than 10 microns/pixel. The CV value of the sample was less than 10%. The results provide that the diagnostic system can provide more accurate and more automated equipment for nucleic acid extraction, amplification and detection. © 2020 COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.

Exploring active compounds of Jinhua Qinggan Granules for prevention of COVID-19 based on network pharmacology and molecular docking

Objective: To explore the effective chemical constituents of Jinhua Qinggan Granules for treatment of coronavirus disease 2019 (COVID-19). Methods: The compounds and action targets of eleven herbal medicines in Jinhua Qinggan Granules were collected via TCMSP. The genes corresponding to the targets were queried by the UniProt database, then the “herbal medicine-compound-target” network was established by Cytoscape software. The gene ontology (GO) function enrichment analysis and KEGG pathway enrichment analysis were performed by DAVID to predict their mechanism. Molecular docking was used to analyze the binding force of the core effective compounds in the “herbal medicine-compound-target” network with SARS-CoV-2 3CL hydrolase and angiotensin converting enzyme II (ACE2). Results: The “herbal medicine-compound-target” network contained 154 compounds and 276 targets, and the key targets involved PTGS2, HSP90AB1, HSP90AA1, PTGS1, NCOA2, etc. GO function enrichment analysis revealed 278 items, including ATP binding, transcription factor activation and regulation of apoptosis process, etc. KEGG pathway enrichment screened 127 signaling pathways, including TNF, PI3K/Akt and HIF-1 signaling pathways related to lung injury protection. The results of molecular docking showed that formononetin, stigmasterol, beta-sitosterol, anhydroicaritin and other key compounds have a certain degree of affinity with SARS-CoV-2 3CL hydrolase and ACE2. Conclusion: The effective compounds in Jinhua Qinggan Granules regulate multiple signaling pathways via binding ACE2 and acting on targets such as PTGS2, HSP90AB1, HSP90AA1, PTGS1, NCOA2 for the prevention of COVID-19.