Ongoing uncertainty over the relative importance of aerosol transmission of COVID-19 is in part rooted in the history of medical science and our understanding of how epidemic diseases can spread through human populati...Ongoing uncertainty over the relative importance of aerosol transmission of COVID-19 is in part rooted in the history of medical science and our understanding of how epidemic diseases can spread through human populations. Ancient Greek medical theory held that such illnesses are transmitted by airborne pathogenic emanations containing particulate matter(“miasmata”). Notable Roman and medieval scholars such as Varro, Ibn al-Khatib and Fracastoro developed these ideas, combining them with early germ theory and the concept of contagion. A widely held but vaguely defined belief in toxic miasmatic mists as a dominant causative agent in disease propagation was overtaken by the science of 19th century microbiology and epidemiology, especially in the study of cholera, which was proven to be mainly transmitted by contaminated water. Airborne disease transmission came to be viewed as burdened by a dubious historical reputation and difficult to demonstrate convincingly. A breakthrough came with the classic mid-20th century work of Wells, Riley and Mills who proved how expiratory aerosols(their “droplet nuclei”)could transport still-infectious tuberculosis bacteria through ventilation systems. The topic of aerosol transmission of pathogenic respiratory diseases assumed a new dimension with the mid-late 20th century “Great Acceleration” of an increasingly hypermobile human population repeatedly infected by different strains of zoonotic viruses, and has taken centre stage this century in response to outbreaks of new respiratory infections that include coronaviruses. From a geoscience perspective, the consequences of pandemic-status diseases such as COVID-19, produced by viral pathogens utilising aerosols to infect a human population currently approaching 8 billion, are far-reaching and unprecedented. The obvious and sudden impacts on for example waste plastic production, water and air quality and atmospheric chemistry are accelerating human awareness of current environmental challenges. As such, the “anthropause”lockdown enforced by COVID-19 may come to be seen as a harbinger of change great enough to be preserved in the Anthropocene stratal record.展开更多
Chinese forensic medicine has a long and brilliant history,and the forensic knowledge in ancient China represents the world’s highest medicolegal level at the time.Among all extant essays and works on China’s early ...Chinese forensic medicine has a long and brilliant history,and the forensic knowledge in ancient China represents the world’s highest medicolegal level at the time.Among all extant essays and works on China’s early medical jurisprudence,Xiyuan Jilu(Records for Vindication)written by Song Ci in 1247 CE,during the Southern Song dynasty,is the oldest text on legal medicine in the world.Subsequently,this work went through successive editions and expansions.The book was not simply a manual providing instruction on conducting inquests;it also established standards for all judicial practices in ancient China.From the beginning of the 18th century,the earliest existing Yuan edition and subsequent editions of this book were translated.They contributed to the broad dissemination of ancient Chinese forensic culture in the West.By discussing the diffusion of Xiyuan Jilu and its corresponding studies in the Western world,this paper intends to expound on the cultural transmission of early Chinese forensic medicine,and reveal its values and impacts on the history and development of legal medicine worldwide to provide an illustrative example of Sino-Western medical and cultural exchange.展开更多
The activity of the Schaffer collaterals of hippocampal CA3 neurons and hippocampal CA1 neurons has been shown to increase after lfuid percussion injury. Diazepam can inhibit the hy-perexcitability of rat hippocampal ...The activity of the Schaffer collaterals of hippocampal CA3 neurons and hippocampal CA1 neurons has been shown to increase after lfuid percussion injury. Diazepam can inhibit the hy-perexcitability of rat hippocampal neurons after injury, but the mechanism by which it affects excitatory synaptic transmission remains poorly understood. Our results showed that diazepam treatment signiifcantly increased the slope of input-output curves in rat neurons after lfuid per-cussion injury. Diazepam signiifcantly decreased the numbers of spikes evoked by super stimuli in the presence of 15 μmol/L bicuculline, indicating the existence of inhibitory pathways in the injured rat hippocampus. Diazepam effectively increased the paired-pulse facilitation ratio in the hippocampal CA1 region following fluid percussion injury, reduced miniature excitatory postsynaptic potentials, decreased action-potential-dependent glutamine release, and reversed spontaneous glutamine release. These data suggest that diazepam could decrease the lfuid per-cussion injury-induced enhancement of excitatory synaptic transmission in the rat hippocampal CA1 area.展开更多
In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave th...In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltage on the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.展开更多
Background Malaria continues to cause burden in various parts of the world.Haiti,a Caribbean country,is among those aiming to eliminate malaria within a few years.Two surveys were conducted in Haiti during which we ai...Background Malaria continues to cause burden in various parts of the world.Haiti,a Caribbean country,is among those aiming to eliminate malaria within a few years.Two surveys were conducted in Haiti during which we aimed to evaluate the performance of the simple and rapid procedure for ultra-rapid extraction-loop-mediated isothermal amplifcation(PURE-LAMP)method with dried blood spots as an alternative diagnostic method for malaria in the context of low to very low rates of transmission.Methods Febrile and afebrile people were recruited from three administrative divisions within Haiti:Nippes,Sud and Grand’Anse,during the summers of 2017(early August to early September)and 2018(late July to late August).Their blood samples were tested by microscopy,rapid diagnostic tests(RDT),PURE-LAMP and nested PCR to detect Plasmodium infection.Sensitivity,specifcity,positive and negative predictive values and kappa statistics were estimated with the nested PCR results as the gold standard.Results Among 1074 samples analyzed,a positive rate of 8.3%was calculated based on the nested PCR results.Among febrile participants,the rates in 2017 and 2018 were 14.6%and 1.4%,respectively.Three positives were detected among 172 afebrile participants in 2018 by PURE-LAMP and nested PCR,and all three were from the same locality.There was no afebrile participants recruited in 2017.The PURE-LAMP,RDT and microscopy had respective sensitivities of 100%,85.4%and 49.4%.All of the testing methods had specifcities over 99%.Conclusions This study confrmed the high performance of the PURE-LAMP method to detect Plasmodium infection with dried blood spots and recommends its use in targeted mass screening and treatment activities in low endemic areas of malaria.展开更多
基金supported by the Spanish Research Council (CSIC, Project COVID19 CSIC 202030E226)the Generalitat de Catalunya (SGR41)。
文摘Ongoing uncertainty over the relative importance of aerosol transmission of COVID-19 is in part rooted in the history of medical science and our understanding of how epidemic diseases can spread through human populations. Ancient Greek medical theory held that such illnesses are transmitted by airborne pathogenic emanations containing particulate matter(“miasmata”). Notable Roman and medieval scholars such as Varro, Ibn al-Khatib and Fracastoro developed these ideas, combining them with early germ theory and the concept of contagion. A widely held but vaguely defined belief in toxic miasmatic mists as a dominant causative agent in disease propagation was overtaken by the science of 19th century microbiology and epidemiology, especially in the study of cholera, which was proven to be mainly transmitted by contaminated water. Airborne disease transmission came to be viewed as burdened by a dubious historical reputation and difficult to demonstrate convincingly. A breakthrough came with the classic mid-20th century work of Wells, Riley and Mills who proved how expiratory aerosols(their “droplet nuclei”)could transport still-infectious tuberculosis bacteria through ventilation systems. The topic of aerosol transmission of pathogenic respiratory diseases assumed a new dimension with the mid-late 20th century “Great Acceleration” of an increasingly hypermobile human population repeatedly infected by different strains of zoonotic viruses, and has taken centre stage this century in response to outbreaks of new respiratory infections that include coronaviruses. From a geoscience perspective, the consequences of pandemic-status diseases such as COVID-19, produced by viral pathogens utilising aerosols to infect a human population currently approaching 8 billion, are far-reaching and unprecedented. The obvious and sudden impacts on for example waste plastic production, water and air quality and atmospheric chemistry are accelerating human awareness of current environmental challenges. As such, the “anthropause”lockdown enforced by COVID-19 may come to be seen as a harbinger of change great enough to be preserved in the Anthropocene stratal record.
文摘Chinese forensic medicine has a long and brilliant history,and the forensic knowledge in ancient China represents the world’s highest medicolegal level at the time.Among all extant essays and works on China’s early medical jurisprudence,Xiyuan Jilu(Records for Vindication)written by Song Ci in 1247 CE,during the Southern Song dynasty,is the oldest text on legal medicine in the world.Subsequently,this work went through successive editions and expansions.The book was not simply a manual providing instruction on conducting inquests;it also established standards for all judicial practices in ancient China.From the beginning of the 18th century,the earliest existing Yuan edition and subsequent editions of this book were translated.They contributed to the broad dissemination of ancient Chinese forensic culture in the West.By discussing the diffusion of Xiyuan Jilu and its corresponding studies in the Western world,this paper intends to expound on the cultural transmission of early Chinese forensic medicine,and reveal its values and impacts on the history and development of legal medicine worldwide to provide an illustrative example of Sino-Western medical and cultural exchange.
基金supported by the National Natural Science Foundation of China,No.81201984the Scientific Research Project of Shaanxi Provincial Health Department in China,No.2010E03the Yulin Municipal Science and Technology Research and Development Project,No.Sf12-06
文摘The activity of the Schaffer collaterals of hippocampal CA3 neurons and hippocampal CA1 neurons has been shown to increase after lfuid percussion injury. Diazepam can inhibit the hy-perexcitability of rat hippocampal neurons after injury, but the mechanism by which it affects excitatory synaptic transmission remains poorly understood. Our results showed that diazepam treatment signiifcantly increased the slope of input-output curves in rat neurons after lfuid per-cussion injury. Diazepam signiifcantly decreased the numbers of spikes evoked by super stimuli in the presence of 15 μmol/L bicuculline, indicating the existence of inhibitory pathways in the injured rat hippocampus. Diazepam effectively increased the paired-pulse facilitation ratio in the hippocampal CA1 region following fluid percussion injury, reduced miniature excitatory postsynaptic potentials, decreased action-potential-dependent glutamine release, and reversed spontaneous glutamine release. These data suggest that diazepam could decrease the lfuid per-cussion injury-induced enhancement of excitatory synaptic transmission in the rat hippocampal CA1 area.
文摘In recent years,several failures of double circuit transmission line on the same tower due to lightning were happened in Beijing power grid.Although it can be reclosed successful,the lightning strike caused a grave threat to the power grid security.The cause of the accident and the accident process were studied for the sake of further understanding of the impact of lightning on power grid.As an example,110 kV double circuit transmission line(Xilong-line) was analyzed.At first,the system topology was given.Through the analysis on relay protection actions and the fault recorder data,over voltage on the insulator strings was calculated.Based on the analysis and the calculation,accident cause and the process were presented respectively.Secondly,it comes to the conclusion that the lightning failure was caused by counterattack.The wave of the lightning over voltage would spread to the not grounded neutral point of the transformers,and make the neutral protective gap breakdown,then cause freewheeling with the frequency of 50 Hz.As results of the relay protection,the double circuit transmission line all tripped out.Finally,the causes of the accident were proposed that included terrain features,large corner towers,strong thunderstorm weather and poor grounded contact of the tower.
文摘Background Malaria continues to cause burden in various parts of the world.Haiti,a Caribbean country,is among those aiming to eliminate malaria within a few years.Two surveys were conducted in Haiti during which we aimed to evaluate the performance of the simple and rapid procedure for ultra-rapid extraction-loop-mediated isothermal amplifcation(PURE-LAMP)method with dried blood spots as an alternative diagnostic method for malaria in the context of low to very low rates of transmission.Methods Febrile and afebrile people were recruited from three administrative divisions within Haiti:Nippes,Sud and Grand’Anse,during the summers of 2017(early August to early September)and 2018(late July to late August).Their blood samples were tested by microscopy,rapid diagnostic tests(RDT),PURE-LAMP and nested PCR to detect Plasmodium infection.Sensitivity,specifcity,positive and negative predictive values and kappa statistics were estimated with the nested PCR results as the gold standard.Results Among 1074 samples analyzed,a positive rate of 8.3%was calculated based on the nested PCR results.Among febrile participants,the rates in 2017 and 2018 were 14.6%and 1.4%,respectively.Three positives were detected among 172 afebrile participants in 2018 by PURE-LAMP and nested PCR,and all three were from the same locality.There was no afebrile participants recruited in 2017.The PURE-LAMP,RDT and microscopy had respective sensitivities of 100%,85.4%and 49.4%.All of the testing methods had specifcities over 99%.Conclusions This study confrmed the high performance of the PURE-LAMP method to detect Plasmodium infection with dried blood spots and recommends its use in targeted mass screening and treatment activities in low endemic areas of malaria.
