Inspired by the transmission characteristics of the coronavirus disease 2019(COVID-19),an epidemic model with quarantine and standard incidence rate is first developed,then a novel analysis approach is proposed for fi...Inspired by the transmission characteristics of the coronavirus disease 2019(COVID-19),an epidemic model with quarantine and standard incidence rate is first developed,then a novel analysis approach is proposed for finding the ultimate lower bound of the number of infected individuals,which means that the epidemic is uniformly persistent if the control reproduction number R_(c)>1.This approach can be applied to the related biomat hem at ical models,and some existing works can be improved by using that.In addition,the infection-free equilibrium V^(0)of the model is locally asymptotically stable(LAS)if R_(c)<1 and linearly stable if R_(c)=1;while V^(0)is unstable if R_(c)>1.展开更多
In order to protect endangered prey,ecologists suggest introducing parasites into predators which have achieved the expected goal in practice.Then how to explain the inherent mechanism and validate the effectiveness o...In order to protect endangered prey,ecologists suggest introducing parasites into predators which have achieved the expected goal in practice.Then how to explain the inherent mechanism and validate the effectiveness of this approach theoretically?In response to this question,we propose an eco-epidemiological system with the standard incidence rate and the anti-predator behavior in this paper,where the predator population is infected by parasites.We show the existence and local stability of equilibria for the system,and verify the occurrence of Hopf bifurcation.Theoretical and numerical results suggest that the fear effect reduces the density of the predator population but has no effect on the density of prey population.In addition,the cost of fear may not only break the stability of the equilibrium of the system,but also induce the equilibrium to change from unstable to stable.Based on the theoretical analysis,we confirm that introducing parasites into the predator population is an effective method to protect endangered prey.展开更多
Pancreatic cancer incidence is increasing worldwide.While the developed countries have seen a greater increase in the age-standardized incidence rate of pancreatic cancer（29%from 1990-2013）,developing countries are ...Pancreatic cancer incidence is increasing worldwide.While the developed countries have seen a greater increase in the age-standardized incidence rate of pancreatic cancer（29%from 1990-2013）,developing countries are also not spared（10%increase during the same time period）.展开更多
Background:Cancer incidence and mortality have received critical attention during the long-term management of morbidities in patients with autoimmune diseases(AIDs).This study aimed to investigate and compare the risk...Background:Cancer incidence and mortality have received critical attention during the long-term management of morbidities in patients with autoimmune diseases(AIDs).This study aimed to investigate and compare the risk of cancer associated with five major AIDs in a large-scale Chinese cohort.Methods:A total of 8,120 AID patients consecutively admitted to a national tertiary referral center in China were included and followed-up for 38,726.55 patient-years,including those with systemic lupus erythematosus(SLE),rheumatoid arthritis(RA),Sjoren’s syndrome(SS),systemic scleroderma(SSc),and idiopathic inflammatory myositis(IIM).Demographic data,cancer incidence,predilecting sites and cancer onset time were recorded and compared among the five AIDs.Results:Four hundred and thirty(5.3%)patients developed cancer.Their median agewas 57.5 years and AID durationwas 79.8 months.The estimated total standardized incidence ratio(SIR)of cancer in AIDs patients was 3.37,with the highest SIR observed in IIM(4.31),followed by RA(3.99),SSc(3.77),SS(2.88)and SLE(2.58).The increased SIR of cancers in AID patients showed a female predominance(female vs.male:3.59 vs.2.77)and younger patient involvement(age<50 vs.≥50 years:4.88 vs.3.04).Patientswith SLE had increased SIRs for developing hematologic malignancies and solid tumors located in the urinary bladder,corpus uteri and cervix uteri.Patients with SS had a significantly high SIR for developing non-Hodgkin’s lymphoma.Within 3 years of IIM diagnosis,74.6%of the patients developed cancer and they had a high risk of ovarian cancer.RA was associated with a wide distribution of scancers,including non-Hodgkin’s lymphoma,gynecologic,urinary tract,thyroid gland and lung cancers.SSc patients had increased SIRs for developing cervical uterine,lung,and breast cancers.Conclusion:Patients with five major AIDs in China had an increased risk of developing cancer,with a predominance in women and younger patients,although cancer incidence,predilection sites and cancer onset time may vary greatly in each AID entity.展开更多
A hepatitis B virus （HBV） model with standard incidence and the uninfected cells growing logistically is investigated. By analyzing the corresponding characteristic equations, the local stability of the infection-fr...A hepatitis B virus （HBV） model with standard incidence and the uninfected cells growing logistically is investigated. By analyzing the corresponding characteristic equations, the local stability of the infection-free and infection equilibria is discussed, respectively. Further, the existence of an orbitally asymptotically stable periodic orbit is also studied. By means of the theory of competitive systems and compound matrices, sufficient conditions are derived for the global stability of the infection-free and infection equilibria, respectively. At last, numerical simulations are carried out to illustrate the main results.展开更多
基金partially supported by the National Natural Science Foundation of China(Nos.11901027,11971273and 12126426)the Major Program of the National Natural Science Foundation of China(No.12090014)+4 种基金the State Key Program of the National Natural Science Foundation of China(No.12031020)the Natural Science Foundation of Shandong Province(No.ZR2018MA004)the China Postdoctoral Science Foundation(No.2021M703426)the Pyramid Talent Training Project of BUCEA(No.JDYC20200327)the BUCEA Post Graduate Innovation Project(No.PG2022143)。
文摘Inspired by the transmission characteristics of the coronavirus disease 2019(COVID-19),an epidemic model with quarantine and standard incidence rate is first developed,then a novel analysis approach is proposed for finding the ultimate lower bound of the number of infected individuals,which means that the epidemic is uniformly persistent if the control reproduction number R_(c)>1.This approach can be applied to the related biomat hem at ical models,and some existing works can be improved by using that.In addition,the infection-free equilibrium V^(0)of the model is locally asymptotically stable(LAS)if R_(c)<1 and linearly stable if R_(c)=1;while V^(0)is unstable if R_(c)>1.
文摘In order to protect endangered prey,ecologists suggest introducing parasites into predators which have achieved the expected goal in practice.Then how to explain the inherent mechanism and validate the effectiveness of this approach theoretically?In response to this question,we propose an eco-epidemiological system with the standard incidence rate and the anti-predator behavior in this paper,where the predator population is infected by parasites.We show the existence and local stability of equilibria for the system,and verify the occurrence of Hopf bifurcation.Theoretical and numerical results suggest that the fear effect reduces the density of the predator population but has no effect on the density of prey population.In addition,the cost of fear may not only break the stability of the equilibrium of the system,but also induce the equilibrium to change from unstable to stable.Based on the theoretical analysis,we confirm that introducing parasites into the predator population is an effective method to protect endangered prey.
文摘Pancreatic cancer incidence is increasing worldwide.While the developed countries have seen a greater increase in the age-standardized incidence rate of pancreatic cancer（29%from 1990-2013）,developing countries are also not spared（10%increase during the same time period）.
基金This study was supported by the grants from the National Natural Science Foundation of China(81801633,81788101,and 81630044)Chinese Academy of Medical Science Innovation Fund for Medical Sciences(CIFMS 2020-I2MC&T-B-011,2021-I2M-1-017,2021-I2M-1-047,2021-I2M-1-040,and 2021-I2M-1-016)CSCO Pilot Oncology Research Fund(Y-2019AZMS-0452).
文摘Background:Cancer incidence and mortality have received critical attention during the long-term management of morbidities in patients with autoimmune diseases(AIDs).This study aimed to investigate and compare the risk of cancer associated with five major AIDs in a large-scale Chinese cohort.Methods:A total of 8,120 AID patients consecutively admitted to a national tertiary referral center in China were included and followed-up for 38,726.55 patient-years,including those with systemic lupus erythematosus(SLE),rheumatoid arthritis(RA),Sjoren’s syndrome(SS),systemic scleroderma(SSc),and idiopathic inflammatory myositis(IIM).Demographic data,cancer incidence,predilecting sites and cancer onset time were recorded and compared among the five AIDs.Results:Four hundred and thirty(5.3%)patients developed cancer.Their median agewas 57.5 years and AID durationwas 79.8 months.The estimated total standardized incidence ratio(SIR)of cancer in AIDs patients was 3.37,with the highest SIR observed in IIM(4.31),followed by RA(3.99),SSc(3.77),SS(2.88)and SLE(2.58).The increased SIR of cancers in AID patients showed a female predominance(female vs.male:3.59 vs.2.77)and younger patient involvement(age<50 vs.≥50 years:4.88 vs.3.04).Patientswith SLE had increased SIRs for developing hematologic malignancies and solid tumors located in the urinary bladder,corpus uteri and cervix uteri.Patients with SS had a significantly high SIR for developing non-Hodgkin’s lymphoma.Within 3 years of IIM diagnosis,74.6%of the patients developed cancer and they had a high risk of ovarian cancer.RA was associated with a wide distribution of scancers,including non-Hodgkin’s lymphoma,gynecologic,urinary tract,thyroid gland and lung cancers.SSc patients had increased SIRs for developing cervical uterine,lung,and breast cancers.Conclusion:Patients with five major AIDs in China had an increased risk of developing cancer,with a predominance in women and younger patients,although cancer incidence,predilection sites and cancer onset time may vary greatly in each AID entity.
文摘A hepatitis B virus （HBV） model with standard incidence and the uninfected cells growing logistically is investigated. By analyzing the corresponding characteristic equations, the local stability of the infection-free and infection equilibria is discussed, respectively. Further, the existence of an orbitally asymptotically stable periodic orbit is also studied. By means of the theory of competitive systems and compound matrices, sufficient conditions are derived for the global stability of the infection-free and infection equilibria, respectively. At last, numerical simulations are carried out to illustrate the main results.
