The basic reproduction number of an infectious agent is the average number of infections one case can generate over the course of the infectious period,in a naïve,uninfected population.It is well-known that the e...The basic reproduction number of an infectious agent is the average number of infections one case can generate over the course of the infectious period,in a naïve,uninfected population.It is well-known that the estimation of this number may vary due to several methodological issues,including different assumptions and choice of parameters,utilized models,used datasets and estimation period.With the spreading of the novel coronavirus(2019-nCoV)infection,the reproduction number has been found to vary,reflecting the dynamics of transmission of the coronavirus outbreak as well as the case reporting rate.Due to significant variations in the control strategies,which have been changing over time,and thanks to the introduction of detection technologies that have been rapidly improved,enabling to shorten the time from infection/symptoms onset to diagnosis,leading to faster confirmation of the new coronavirus cases,our previous estimations on the transmission risk of the 2019-nCoV need to be revised.By using time-dependent contact and diagnose rates,we refit our previously proposed dynamics transmission model to the data available until January 29th,2020 and re-estimated the effective daily reproduction ratio that better quantifies the evolution of the interventions.We estimated when the effective daily reproduction ratio has fallen below 1 and when the epidemics will peak.Our updated findings suggest that the best measure is persistent and strict self-isolation.The epidemics will continue to grow,and can peak soon with the peak time depending highly on the public health interventions practically implemented.展开更多
In 2019,cardiovascular disease(CVD)accounted for 46.74%and 44.26%of all deaths in rural and urban areas,respectively.Two out of every five deaths were due to CVD.It is estimated that about 330 million patients suffer ...In 2019,cardiovascular disease(CVD)accounted for 46.74%and 44.26%of all deaths in rural and urban areas,respectively.Two out of every five deaths were due to CVD.It is estimated that about 330 million patients suffer from CVD in China.The number of patients suffering from stroke,coronary heart disease,heart failure,pulmonary heart disease,atrial fibrillation,rheumatic heart disease,congenital heart disease,lower extremity artery disease and hypertension are 13.00 million,11.39 million,8.90 million,5.00 million,4.87 million,2.50 million,2.00 million,45.30 million,and 245.00 million,respectively.Given that China is challenged by the dual pressures of population aging and steady rise in the prevalence of metabolic risk factors,the burden caused by CVD will continue to increase,which has set new requirements for CVD prevention and treatment and the allocation of medical resources in China.It is important to reduce the prevalence through primary prevention,increase the allocation of medical resources for CVD emergency and critical care,and provide rehabilitation services and secondary prevention to reduce the risk of recurrence,re-hospitalization and disability in CVD survivors.The number of people suffering from hypertension,dyslipidemia and diabetes in China has reached hundreds of millions.Since blood pressure,blood lipids,and blood glucose levels rise mostly insidiously,vascular disease or even serious events such as myocardial infarction and stroke often already occured at the time of detection in this population.Hence,more strategies and tasks should be taken to prevent risk factors such as hypertension,dyslipidemia,diabetes,obesity,and smoking,and more efforts should be made in the assessment of cardiovascular health status and the prevention,treatment,and research of early pathological changes.展开更多
Background:As reported by the World Health Organization,a novel coronavirus(2019-nCoV)was identified as the causative virus of Wuhan pneumonia of unknown etiology by Chinese authorities on 7 January,2020.The virus was...Background:As reported by the World Health Organization,a novel coronavirus(2019-nCoV)was identified as the causative virus of Wuhan pneumonia of unknown etiology by Chinese authorities on 7 January,2020.The virus was named as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)by International Committee on Taxonomy of Viruses on 11 February,2020.This study aimed to develop a mathematical model for calculating the transmissibility of the virus.Methods:In this study,we developed a Bats-Hosts-Reservoir-People transmission network model for simulating the potential transmission from the infection source(probably be bats)to the human infection.Since the Bats-HostsReservoir network was hard to explore clearly and public concerns were focusing on the transmission from Huanan Seafood Wholesale Market(reservoir)to people,we simplified the model as Reservoir-People(RP)transmission network model.The next generation matrix approach was adopted to calculate the basic reproduction number(R0)from the RP model to assess the transmissibility of the SARS-CoV-2.Results:The value of R0 was estimated of 2.30 from reservoir to person and 3.58 from person to person which means that the expected number of secondary infections that result from introducing a single infected individual into an otherwise susceptible population was 3.58.Conclusions:Our model showed that the transmissibility of SARS-CoV-2 was higher than the Middle East respiratory syndrome in the Middle East countries,similar to severe acute respiratory syndrome,but lower than MERS in the Republic of Korea.展开更多
The LAGFD-WAM wave model is a third generation wave model. In the present paper the physical aspect of the model was shown in great detail including energy spectrum balance equation, complicated characteristics equati...The LAGFD-WAM wave model is a third generation wave model. In the present paper the physical aspect of the model was shown in great detail including energy spectrum balance equation, complicated characteristics equations and source functions.展开更多
To analyze the effect of basic variable on failure probability in reliability analysis,a moment-independent importance measure of the basic random variable is proposed,and its properties are analyzed and verified.Base...To analyze the effect of basic variable on failure probability in reliability analysis,a moment-independent importance measure of the basic random variable is proposed,and its properties are analyzed and verified.Based on this work,the importance measure of the basic variable on the failure probability is compared with that on the distribution density of the response.By use of the probability density evolution method,a solution is established to solve two importance measures,which can efficiently avoid the difficulty in solving the importance measures.Some numerical examples and engineering examples are used to demonstrate the proposed importance measure on the failure probability and that on the distribution density of the response.The results show that the proposed importance measure can effectively describe the effect of the basic variable on the failure probability from the distribution density of the basic variable.Additionally,the results show that the established solution on the probability density evolution is efficient for the importance measures.展开更多
AIM: To investigate the anti-tumor effect of Chinese medicine Gecko on human esophageal carcinoma cell lines and xenografted sarcoma 180 in Kunming mice and its mechanism. METHODS: The serum pharmacological method was...AIM: To investigate the anti-tumor effect of Chinese medicine Gecko on human esophageal carcinoma cell lines and xenografted sarcoma 180 in Kunming mice and its mechanism. METHODS: The serum pharmacological method was used in vitro . The growth rates of the human esophageal carcinoma cells (EC9706 or EC1) were measured by a modifi ed 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The transplanted tumor model of the mouse S180 sarcoma was established. Fifty mice were randomly divided into fi ve groups (n = 10). Three Gecko groups were treated respectively with oral administration of Gecko powder at a daily dose of 13.5 g/kg, 9 g/kg, and 4.5 g/kg. The negative group (NS group) was treated with oral administration of an equal volume of saline and the positive group (CTX group) was treated with 100 mg/kg Cytoxan by intraperitoneal injection at the fi rst day. After 2 wk of treatment, the anti-tumor activity was evaluated by tumor tissue weighing. The impact on immune organ was detected based on the thymus index, spleen index, phagocytic rate and phagocytic index. The protein expression of vascular endothelingrowth factor (VEGF) and basic fibroblast growth factor (bFGF) were detected by immunohistochemistry. The cell apoptotic rate was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: The A value in each group treated with Gecko after 72 h was reduced signif icantly in EC9706 and in EC1. The tumor weight in each group of Gecko was decreased signifi cantly (1.087 ± 0.249 vs 2.167 ± 0.592; 1.021 ± 0.288 vs 2.167 ± 0.592; 1.234 ± 0.331 vs 2.167 ± 0.592; P < 0.01, respectively). However, the thymus index and Spleen index of mice in Gecko groups had no significant difference compared with the NS group. The immunoreactive score of VEGF and bFGF protein expression of each Gecko group by immunohistochemical staining were lowered signifi cantly. The apoptosis index (AI) of each group was increased progressively with increase of dose 展开更多
Bemisia tabaci(Gennadius) biotype B,called a "superbug",is one of the most harmful biotypes of this species complex worldwide.In this report,the invasive mechanism and management of B.tabaci biotype B,based ...Bemisia tabaci(Gennadius) biotype B,called a "superbug",is one of the most harmful biotypes of this species complex worldwide.In this report,the invasive mechanism and management of B.tabaci biotype B,based on our 5-year studies,are presented.Six B.tabaci biotypes,B,Q,ZHJ1,ZHJ2,ZHJ3 and FJ1,have been identified in China.Biotype B dominates the other biotypes in many regions of the country.Genetic diversity in biotype B might be induced by host plant,geographical conditions,and/or insecticidal application.The activities of CarE(carboxylesterase) and GSTs(glutathione-S-transferase) in biotype B reared on cucumber and squash were greater than on other host plants,which might have increased its resistance to insecticides.The higher activities of detoxification enzymes in biotype B might be induced by the secondary metabolites in host plants.Higher adaptive ability of biotype B adults to adverse conditions might be linked to the expression of heat shock protein genes.The indigenous B.tabaci biotypes were displaced by the biotype B within 225 d.The asymmetric mating interactions and mutualism between biotype B and begomoviruses via its host plants speed up widespread invasion and displacement of other biotypes.B.tabaci biotype B displaced Trialeurodes vaporariorum(Westwood) after 4-7 generations under glasshouse conditions.Greater adaptive ability of the biotype B to adverse conditions and its rapid population increase might be the reasons of its successful displacement of T.vaporariorum.Greater ability of the biotype B to switch to different host plants may enrich its host plants,which might enable it to better compete with T.vaporariorum.Native predatory natural enemies possess greater ability to suppress B.tabaci under field conditions.The kairomones in the 3rd and 4th instars of biotype B may provide an important stimulus in host searching and location by its parasitoids.The present results provide useful information in explaining the mechanisms of genetic diversity,evolution and molecular eco-adaptation of biotype展开更多
基金This research was funded by the National Natural Science Foundation of China(grant numbers:11631012(YX,ST),61772017(ST))by the Canada Research Chair Program(grant number:230720(JW)the Natural Sciences and Engineering Research Council of Canada(Grant number:105588-2011(JW).
文摘The basic reproduction number of an infectious agent is the average number of infections one case can generate over the course of the infectious period,in a naïve,uninfected population.It is well-known that the estimation of this number may vary due to several methodological issues,including different assumptions and choice of parameters,utilized models,used datasets and estimation period.With the spreading of the novel coronavirus(2019-nCoV)infection,the reproduction number has been found to vary,reflecting the dynamics of transmission of the coronavirus outbreak as well as the case reporting rate.Due to significant variations in the control strategies,which have been changing over time,and thanks to the introduction of detection technologies that have been rapidly improved,enabling to shorten the time from infection/symptoms onset to diagnosis,leading to faster confirmation of the new coronavirus cases,our previous estimations on the transmission risk of the 2019-nCoV need to be revised.By using time-dependent contact and diagnose rates,we refit our previously proposed dynamics transmission model to the data available until January 29th,2020 and re-estimated the effective daily reproduction ratio that better quantifies the evolution of the interventions.We estimated when the effective daily reproduction ratio has fallen below 1 and when the epidemics will peak.Our updated findings suggest that the best measure is persistent and strict self-isolation.The epidemics will continue to grow,and can peak soon with the peak time depending highly on the public health interventions practically implemented.
文摘In 2019,cardiovascular disease(CVD)accounted for 46.74%and 44.26%of all deaths in rural and urban areas,respectively.Two out of every five deaths were due to CVD.It is estimated that about 330 million patients suffer from CVD in China.The number of patients suffering from stroke,coronary heart disease,heart failure,pulmonary heart disease,atrial fibrillation,rheumatic heart disease,congenital heart disease,lower extremity artery disease and hypertension are 13.00 million,11.39 million,8.90 million,5.00 million,4.87 million,2.50 million,2.00 million,45.30 million,and 245.00 million,respectively.Given that China is challenged by the dual pressures of population aging and steady rise in the prevalence of metabolic risk factors,the burden caused by CVD will continue to increase,which has set new requirements for CVD prevention and treatment and the allocation of medical resources in China.It is important to reduce the prevalence through primary prevention,increase the allocation of medical resources for CVD emergency and critical care,and provide rehabilitation services and secondary prevention to reduce the risk of recurrence,re-hospitalization and disability in CVD survivors.The number of people suffering from hypertension,dyslipidemia and diabetes in China has reached hundreds of millions.Since blood pressure,blood lipids,and blood glucose levels rise mostly insidiously,vascular disease or even serious events such as myocardial infarction and stroke often already occured at the time of detection in this population.Hence,more strategies and tasks should be taken to prevent risk factors such as hypertension,dyslipidemia,diabetes,obesity,and smoking,and more efforts should be made in the assessment of cardiovascular health status and the prevention,treatment,and research of early pathological changes.
基金This study was supported by Xiamen New Coronavirus Prevention and Control Emergency Tackling Special Topic Program(No:3502Z2020YJ03).
文摘Background:As reported by the World Health Organization,a novel coronavirus(2019-nCoV)was identified as the causative virus of Wuhan pneumonia of unknown etiology by Chinese authorities on 7 January,2020.The virus was named as severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)by International Committee on Taxonomy of Viruses on 11 February,2020.This study aimed to develop a mathematical model for calculating the transmissibility of the virus.Methods:In this study,we developed a Bats-Hosts-Reservoir-People transmission network model for simulating the potential transmission from the infection source(probably be bats)to the human infection.Since the Bats-HostsReservoir network was hard to explore clearly and public concerns were focusing on the transmission from Huanan Seafood Wholesale Market(reservoir)to people,we simplified the model as Reservoir-People(RP)transmission network model.The next generation matrix approach was adopted to calculate the basic reproduction number(R0)from the RP model to assess the transmissibility of the SARS-CoV-2.Results:The value of R0 was estimated of 2.30 from reservoir to person and 3.58 from person to person which means that the expected number of secondary infections that result from introducing a single infected individual into an otherwise susceptible population was 3.58.Conclusions:Our model showed that the transmissibility of SARS-CoV-2 was higher than the Middle East respiratory syndrome in the Middle East countries,similar to severe acute respiratory syndrome,but lower than MERS in the Republic of Korea.
文摘The LAGFD-WAM wave model is a third generation wave model. In the present paper the physical aspect of the model was shown in great detail including energy spectrum balance equation, complicated characteristics equations and source functions.
基金supported by the National Natural Science Foundation of China (Grant Nos NSFC1057211, 50875213)New Century Excellent Talents in University of China (Grant No NCET-05-0868)+2 种基金Aviation Science Foundation of China (Grant No 2007ZA53012)National High Technology Research and Development Program of China (Grant No 2007AA04Z401)the Important National Science & Technology Specific Projects (Grant No 2009ZX04014-015-03)
文摘To analyze the effect of basic variable on failure probability in reliability analysis,a moment-independent importance measure of the basic random variable is proposed,and its properties are analyzed and verified.Based on this work,the importance measure of the basic variable on the failure probability is compared with that on the distribution density of the response.By use of the probability density evolution method,a solution is established to solve two importance measures,which can efficiently avoid the difficulty in solving the importance measures.Some numerical examples and engineering examples are used to demonstrate the proposed importance measure on the failure probability and that on the distribution density of the response.The results show that the proposed importance measure can effectively describe the effect of the basic variable on the failure probability from the distribution density of the basic variable.Additionally,the results show that the established solution on the probability density evolution is efficient for the importance measures.
基金Doctor Fund of Henan University of Science & Technology, No. 20071201
文摘AIM: To investigate the anti-tumor effect of Chinese medicine Gecko on human esophageal carcinoma cell lines and xenografted sarcoma 180 in Kunming mice and its mechanism. METHODS: The serum pharmacological method was used in vitro . The growth rates of the human esophageal carcinoma cells (EC9706 or EC1) were measured by a modifi ed 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The transplanted tumor model of the mouse S180 sarcoma was established. Fifty mice were randomly divided into fi ve groups (n = 10). Three Gecko groups were treated respectively with oral administration of Gecko powder at a daily dose of 13.5 g/kg, 9 g/kg, and 4.5 g/kg. The negative group (NS group) was treated with oral administration of an equal volume of saline and the positive group (CTX group) was treated with 100 mg/kg Cytoxan by intraperitoneal injection at the fi rst day. After 2 wk of treatment, the anti-tumor activity was evaluated by tumor tissue weighing. The impact on immune organ was detected based on the thymus index, spleen index, phagocytic rate and phagocytic index. The protein expression of vascular endothelingrowth factor (VEGF) and basic fibroblast growth factor (bFGF) were detected by immunohistochemistry. The cell apoptotic rate was detected by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) assay. RESULTS: The A value in each group treated with Gecko after 72 h was reduced signif icantly in EC9706 and in EC1. The tumor weight in each group of Gecko was decreased signifi cantly (1.087 ± 0.249 vs 2.167 ± 0.592; 1.021 ± 0.288 vs 2.167 ± 0.592; 1.234 ± 0.331 vs 2.167 ± 0.592; P < 0.01, respectively). However, the thymus index and Spleen index of mice in Gecko groups had no significant difference compared with the NS group. The immunoreactive score of VEGF and bFGF protein expression of each Gecko group by immunohistochemical staining were lowered signifi cantly. The apoptosis index (AI) of each group was increased progressively with increase of dose
基金Supported by the National Basic Research and Development Program of China (973 Program) of China (Grant No.2009CB119200)
文摘Bemisia tabaci(Gennadius) biotype B,called a "superbug",is one of the most harmful biotypes of this species complex worldwide.In this report,the invasive mechanism and management of B.tabaci biotype B,based on our 5-year studies,are presented.Six B.tabaci biotypes,B,Q,ZHJ1,ZHJ2,ZHJ3 and FJ1,have been identified in China.Biotype B dominates the other biotypes in many regions of the country.Genetic diversity in biotype B might be induced by host plant,geographical conditions,and/or insecticidal application.The activities of CarE(carboxylesterase) and GSTs(glutathione-S-transferase) in biotype B reared on cucumber and squash were greater than on other host plants,which might have increased its resistance to insecticides.The higher activities of detoxification enzymes in biotype B might be induced by the secondary metabolites in host plants.Higher adaptive ability of biotype B adults to adverse conditions might be linked to the expression of heat shock protein genes.The indigenous B.tabaci biotypes were displaced by the biotype B within 225 d.The asymmetric mating interactions and mutualism between biotype B and begomoviruses via its host plants speed up widespread invasion and displacement of other biotypes.B.tabaci biotype B displaced Trialeurodes vaporariorum(Westwood) after 4-7 generations under glasshouse conditions.Greater adaptive ability of the biotype B to adverse conditions and its rapid population increase might be the reasons of its successful displacement of T.vaporariorum.Greater ability of the biotype B to switch to different host plants may enrich its host plants,which might enable it to better compete with T.vaporariorum.Native predatory natural enemies possess greater ability to suppress B.tabaci under field conditions.The kairomones in the 3rd and 4th instars of biotype B may provide an important stimulus in host searching and location by its parasitoids.The present results provide useful information in explaining the mechanisms of genetic diversity,evolution and molecular eco-adaptation of biotype
