磁能恢复开关MERS(magnetic energy recovery switch)是一种新型的无功补偿装置,它相较于其他无功补偿装置,具有结构简单、易于控制和损耗低等诸多优点,但在进行无功功率补偿的过程中会产生谐波电流。首先,在对MERS的结构和控制方法阐...磁能恢复开关MERS(magnetic energy recovery switch)是一种新型的无功补偿装置,它相较于其他无功补偿装置,具有结构简单、易于控制和损耗低等诸多优点,但在进行无功功率补偿的过程中会产生谐波电流。首先,在对MERS的结构和控制方法阐述的基础上建立了三相对称系统中SVC-MERS的数学模型,讨论分析了控制参数对三相对称系统中线电流谐波特性的影响;进而提出了控制参数的优化设计方法。仿真和实验结果表明,通过控制参数的优化设计可以有效地减小三相对称系统中线电流的谐波含量,所提控制参数的优化设计方法是可行的。展开更多
Hospital-acquired infections(HAIs) are serious problems for healthcare systems, especially in developing countries where public health infrastructure and technology for infection preventions remain undeveloped. Here, ...Hospital-acquired infections(HAIs) are serious problems for healthcare systems, especially in developing countries where public health infrastructure and technology for infection preventions remain undeveloped. Here, we characterized how strategy and technology could be mobilized to improve the effectiveness of infection prevention and control in hospitals during the outbreaks of Ebola, Middle East respiratory syndrome(MERS), and severe acute respiratory syndrome(SARS) in Asia and West Africa. Published literature on the hospital-borne outbreaks of SARS, Ebola, and MERS in Asia and West Africa was comprehensively reviewed. The results showed that healthcare systems and hospital management in affected healthcare facilities had poor strategies and inadequate technologies and human resources for the prevention and control of HAIs, which led to increased morbidity, mortality, and unnecessary costs. We recommend that governments worldwide enforce disaster risk management, even when no outbreaks are imminent. Quarantine and ventilation functions should be taken into consideration in architectural design of hospitals and healthcare facilities. We also recommend that health authorities invest in training healthcare workers for disease outbreak response, as their preparedness is essential to reducing disaster risk.展开更多
The recent outbreak of coronavirus disease(COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has already affected a large population of the world. SARS-CoV-2 belongs to the same...The recent outbreak of coronavirus disease(COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has already affected a large population of the world. SARS-CoV-2 belongs to the same family of severe acute respiratory syndrome coronavirus(SARS-CoV) and Middle East respiratory syndrome coronavirus(MERSCoV). COVID-19 has a complex pathology involving severe acute respiratory infection, hyper-immune response, and coagulopathy. At present, there is no therapeutic drug or vaccine approved for the disease. There is an urgent need for an ideal animal model that can reflect clinical symptoms and underlying etiopathogenesis similar to COVID-19 patients which can be further used for evaluation of underlying mechanisms, potential vaccines, and therapeutic strategies. The current review provides a paramount insight into the available animal models of SARS-CoV-2, SARS-CoV, and MERS-CoV for the management of the diseases.展开更多
The papain-like protease(PL^(pro)) of Middle-East respiratory syndrome coronavirus(MERS-CoV) has proteolytic,deubiquitinating,and de ISGylating activities.The latter two are involved in the suppression of the antivira...The papain-like protease(PL^(pro)) of Middle-East respiratory syndrome coronavirus(MERS-CoV) has proteolytic,deubiquitinating,and de ISGylating activities.The latter two are involved in the suppression of the antiviral innate immune response of the host cell.To contribute to an understanding of this process,we present here the X-ray crystal structure of a complex between MERS-CoV PL^(pro) and human ubiquitin(Ub) that is devoid of any covalent linkage between the two proteins.Five regions of the PL^(pro) bind to two areas of the Ub.The C-terminal five residues of Ub,RLRGG,are similar to the P5–P1 residues of the polyprotein substrates of the PL^(pro) and are responsible for the major part of the interaction between the two macromolecules.Through sitedirected mutagenesis,we demonstrate that conserved Asp165 and non-conserved Asp164 are important for the catalytic activities of MERS-CoV PL^(pro).The enzyme appears not to be optimized for catalytic efficiency; thus,replacement of Phe269 by Tyr leads to increased peptidolytic and deubiquitinating activities.Ubiquitin binding by MERS-CoV PL^(pro) involves remarkable differences compared to the corresponding complex with SARS-CoV PL^(pro).The structure and the mutational study help understand common and unique features of the deubiquitinating activity of MERS-CoV PL^(pro).展开更多
Background: Middle East respiratory syndrome coronavirus(MERS-Co V), which is not fully understood in regard to certain transmission routes and pathogenesis and lacks specific therapeutics and vaccines, poses a global...Background: Middle East respiratory syndrome coronavirus(MERS-Co V), which is not fully understood in regard to certain transmission routes and pathogenesis and lacks specific therapeutics and vaccines, poses a global threat to public health.Methods: To simulate the clinical aerosol transmission route, h DPP4 transgenic mice were infected with MERS-Co V by an animal nose-only exposure device and compared with instillation-inoculated mice. The challenged mice were observed for 14 consecutive days and necropsied on days 3, 5, 7, and 9 to analyze viral load, histopathology, viral antigen distribution, and cytokines in tissues.Results: MERS-Co V aerosol-infected mice with an incubation period of 5-7 days showed weight loss on days 7-11, obvious lung lesions on day 7, high viral loads in the lungs on days 3-9 and in the brain on days 7-9, and 60% survival. MERS-Co V instillation-inoculated mice exhibited clinical signs on day 1, obvious lung lesions on days 3-5, continuous weight loss, 0% survival by day 5, and high viral loads in the lungs and brain on days 3-5. Viral antigen and high levels of proinflammatory cytokines and chemokines were detected in the aerosol and instillation groups. Disease, lung lesion, and viral replication progressions were slower in the MERS-Co V aerosol-infected mice than in the MERS-Co V instillation-inoculated mice.Conclusion: h DPP4 transgenic mice were successfully infected with MERS-Co V aerosols via an animal nose-only exposure device, and aerosol-and instillation-infected mice simulated the clinical symptoms of moderate diffuse interstitial pneumonia. However, the transgenic mice exposed to aerosol MERS-Co V developed disease and lung pathology progressions that more closely resembled those observed in humans.展开更多
文摘磁能恢复开关MERS(magnetic energy recovery switch)是一种新型的无功补偿装置,它相较于其他无功补偿装置,具有结构简单、易于控制和损耗低等诸多优点,但在进行无功功率补偿的过程中会产生谐波电流。首先,在对MERS的结构和控制方法阐述的基础上建立了三相对称系统中SVC-MERS的数学模型,讨论分析了控制参数对三相对称系统中线电流谐波特性的影响;进而提出了控制参数的优化设计方法。仿真和实验结果表明,通过控制参数的优化设计可以有效地减小三相对称系统中线电流的谐波含量,所提控制参数的优化设计方法是可行的。
基金supported by the Chinese Military System(Grant No.AWS16J023)
文摘Hospital-acquired infections(HAIs) are serious problems for healthcare systems, especially in developing countries where public health infrastructure and technology for infection preventions remain undeveloped. Here, we characterized how strategy and technology could be mobilized to improve the effectiveness of infection prevention and control in hospitals during the outbreaks of Ebola, Middle East respiratory syndrome(MERS), and severe acute respiratory syndrome(SARS) in Asia and West Africa. Published literature on the hospital-borne outbreaks of SARS, Ebola, and MERS in Asia and West Africa was comprehensively reviewed. The results showed that healthcare systems and hospital management in affected healthcare facilities had poor strategies and inadequate technologies and human resources for the prevention and control of HAIs, which led to increased morbidity, mortality, and unnecessary costs. We recommend that governments worldwide enforce disaster risk management, even when no outbreaks are imminent. Quarantine and ventilation functions should be taken into consideration in architectural design of hospitals and healthcare facilities. We also recommend that health authorities invest in training healthcare workers for disease outbreak response, as their preparedness is essential to reducing disaster risk.
文摘The recent outbreak of coronavirus disease(COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) has already affected a large population of the world. SARS-CoV-2 belongs to the same family of severe acute respiratory syndrome coronavirus(SARS-CoV) and Middle East respiratory syndrome coronavirus(MERSCoV). COVID-19 has a complex pathology involving severe acute respiratory infection, hyper-immune response, and coagulopathy. At present, there is no therapeutic drug or vaccine approved for the disease. There is an urgent need for an ideal animal model that can reflect clinical symptoms and underlying etiopathogenesis similar to COVID-19 patients which can be further used for evaluation of underlying mechanisms, potential vaccines, and therapeutic strategies. The current review provides a paramount insight into the available animal models of SARS-CoV-2, SARS-CoV, and MERS-CoV for the management of the diseases.
基金supported by the European Commission through its "SILVER" project (contract no.HEALTHF3-2010-260644)the German Center for Infection Research (DZIF)support by the DFG Cluster of Excellence "Inflammation at Interfaces" (EXC 306)
文摘The papain-like protease(PL^(pro)) of Middle-East respiratory syndrome coronavirus(MERS-CoV) has proteolytic,deubiquitinating,and de ISGylating activities.The latter two are involved in the suppression of the antiviral innate immune response of the host cell.To contribute to an understanding of this process,we present here the X-ray crystal structure of a complex between MERS-CoV PL^(pro) and human ubiquitin(Ub) that is devoid of any covalent linkage between the two proteins.Five regions of the PL^(pro) bind to two areas of the Ub.The C-terminal five residues of Ub,RLRGG,are similar to the P5–P1 residues of the polyprotein substrates of the PL^(pro) and are responsible for the major part of the interaction between the two macromolecules.Through sitedirected mutagenesis,we demonstrate that conserved Asp165 and non-conserved Asp164 are important for the catalytic activities of MERS-CoV PL^(pro).The enzyme appears not to be optimized for catalytic efficiency; thus,replacement of Phe269 by Tyr leads to increased peptidolytic and deubiquitinating activities.Ubiquitin binding by MERS-CoV PL^(pro) involves remarkable differences compared to the corresponding complex with SARS-CoV PL^(pro).The structure and the mutational study help understand common and unique features of the deubiquitinating activity of MERS-CoV PL^(pro).
基金National Science and Technology Major Projects of Infectious Disease, Grant/Award Number: 2018ZX10734401-011
文摘Background: Middle East respiratory syndrome coronavirus(MERS-Co V), which is not fully understood in regard to certain transmission routes and pathogenesis and lacks specific therapeutics and vaccines, poses a global threat to public health.Methods: To simulate the clinical aerosol transmission route, h DPP4 transgenic mice were infected with MERS-Co V by an animal nose-only exposure device and compared with instillation-inoculated mice. The challenged mice were observed for 14 consecutive days and necropsied on days 3, 5, 7, and 9 to analyze viral load, histopathology, viral antigen distribution, and cytokines in tissues.Results: MERS-Co V aerosol-infected mice with an incubation period of 5-7 days showed weight loss on days 7-11, obvious lung lesions on day 7, high viral loads in the lungs on days 3-9 and in the brain on days 7-9, and 60% survival. MERS-Co V instillation-inoculated mice exhibited clinical signs on day 1, obvious lung lesions on days 3-5, continuous weight loss, 0% survival by day 5, and high viral loads in the lungs and brain on days 3-5. Viral antigen and high levels of proinflammatory cytokines and chemokines were detected in the aerosol and instillation groups. Disease, lung lesion, and viral replication progressions were slower in the MERS-Co V aerosol-infected mice than in the MERS-Co V instillation-inoculated mice.Conclusion: h DPP4 transgenic mice were successfully infected with MERS-Co V aerosols via an animal nose-only exposure device, and aerosol-and instillation-infected mice simulated the clinical symptoms of moderate diffuse interstitial pneumonia. However, the transgenic mice exposed to aerosol MERS-Co V developed disease and lung pathology progressions that more closely resembled those observed in humans.
