Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormal...Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause ofinfection and improve with tight glycemic control, which leads to fewer POIs in critically ill surgical patients. Tight glycemic control, such as intensive insulin therapy, has a risk of hypoglycemia. In addition, the optimal targeted blood glucose range to reduce POI remains unknown. Since 2006, we have investigated tight perioperative blood glucose control using a closed-loop artificial endocrine pancreas system, to reduce POI and to avoid hypoglycemia. In this Topic Highlight, we review the relationship between perioperative glycemic control and POI, including the use of the artificial pancreas.展开更多
An HIV infection model with saturated infection rate and double delays is investigated. First, the existence of the infection-free equilibrium E0, the immune-exhausted equilibrium E1 and the infected equilibrium E2 wi...An HIV infection model with saturated infection rate and double delays is investigated. First, the existence of the infection-free equilibrium E0, the immune-exhausted equilibrium E1 and the infected equilibrium E2 with immunity in different conditions is shown. By analyzing the characteristic equation, we study the locally asymptotical stability of the trivial equilibrium, and the existence of Hopf bifurcations when two delays are used as the bifurcation parameter. Furthermore, we apply the Nyquist criterion to estimate the length of delay for which stability continues to hold. Then with suitable Lyapunov function and LaSalle＇s invariance principle, the global stability of the three equilibriums is obtained. Finally, numerical simulations are presented to illustrate the main mathematical results.展开更多
The transmission of schistosomiasis involves latent periods of infected hosts. In this paper, considering the latent periods of infected human, infected bovines and infected snails, we propose a delayed Barbour＇s mod...The transmission of schistosomiasis involves latent periods of infected hosts. In this paper, considering the latent periods of infected human, infected bovines and infected snails, we propose a delayed Barbour＇s model with two definitive hosts and define basic reproductive number. The stability of equilibria for the systems with and without time delays are both investigated. To study the impact of the latent periods on the transmission of schistosomiasis, some sensitivity analysis of the basic reproductive number on the three time delays are carried out. It is shown that the basic reproductive number decreases as the three time delays increase. Furthermore, the impact of the latent periods of infected snails on the system is stronger than that of the latent periods of infected human and infected bovines. Thus, to reduce the prevalence of schistosomiasis infection, prolonging the latent periods of infected snails by some measures could achieve better results than prolonging the latent periods of infected definitive hosts.展开更多
In this paper, an HIV dynamics model with two distributed intracellular delays incorporating Crowley-Martin functional response infection rate is investigated. The authors take into account multiple stage disease tran...In this paper, an HIV dynamics model with two distributed intracellular delays incorporating Crowley-Martin functional response infection rate is investigated. The authors take into account multiple stage disease transmission and the latently infected cells（not yet producing virus） in our system. The authors consider nonnegativity, boundedness of solutions, and global asymptotic stability of the system. By constructing suitable Lyapunov functionals and using the Lyapunov-La Salle invariance principle, the authors prove the global stability of the infected（endemic） equilibrium and the diseasefree equilibrium for time delays. The authors have proven that if the basic reproduction number R_0 is less than unity, then the disease-free equilibrium is globally asymptotically stable, and if R_0 is greater than unity, then the infected equilibrium is globally asymptotically stable. The results obtained show that the global dynamic behaviors of the model are completely determined by the basic reproduction number R_0 and that the time delay does not affect the global asymptotic properties of the model.展开更多
文摘Perioperative hyperglycemia in critically ill surgery patients increases the risk of postoperative infection (POI), which is a common, and often costly, surgical complication. Hyperglycemia is associated with abnormalities in leukocyte function, including granulocyte adherence, impaired phagocytosis, delayed chemotaxis, and depressed bactericidal capacity. These leukocyte deficiencies are the cause ofinfection and improve with tight glycemic control, which leads to fewer POIs in critically ill surgical patients. Tight glycemic control, such as intensive insulin therapy, has a risk of hypoglycemia. In addition, the optimal targeted blood glucose range to reduce POI remains unknown. Since 2006, we have investigated tight perioperative blood glucose control using a closed-loop artificial endocrine pancreas system, to reduce POI and to avoid hypoglycemia. In this Topic Highlight, we review the relationship between perioperative glycemic control and POI, including the use of the artificial pancreas.
基金This work was supported by National Natural Science Foundation of China （61174209, 11471034）.
文摘An HIV infection model with saturated infection rate and double delays is investigated. First, the existence of the infection-free equilibrium E0, the immune-exhausted equilibrium E1 and the infected equilibrium E2 with immunity in different conditions is shown. By analyzing the characteristic equation, we study the locally asymptotical stability of the trivial equilibrium, and the existence of Hopf bifurcations when two delays are used as the bifurcation parameter. Furthermore, we apply the Nyquist criterion to estimate the length of delay for which stability continues to hold. Then with suitable Lyapunov function and LaSalle＇s invariance principle, the global stability of the three equilibriums is obtained. Finally, numerical simulations are presented to illustrate the main mathematical results.
文摘The transmission of schistosomiasis involves latent periods of infected hosts. In this paper, considering the latent periods of infected human, infected bovines and infected snails, we propose a delayed Barbour＇s model with two definitive hosts and define basic reproductive number. The stability of equilibria for the systems with and without time delays are both investigated. To study the impact of the latent periods on the transmission of schistosomiasis, some sensitivity analysis of the basic reproductive number on the three time delays are carried out. It is shown that the basic reproductive number decreases as the three time delays increase. Furthermore, the impact of the latent periods of infected snails on the system is stronger than that of the latent periods of infected human and infected bovines. Thus, to reduce the prevalence of schistosomiasis infection, prolonging the latent periods of infected snails by some measures could achieve better results than prolonging the latent periods of infected definitive hosts.
基金supported partially by Scientific Research Staring Foundation,Henan Normal University(qd13045)
文摘In this paper, an HIV dynamics model with two distributed intracellular delays incorporating Crowley-Martin functional response infection rate is investigated. The authors take into account multiple stage disease transmission and the latently infected cells（not yet producing virus） in our system. The authors consider nonnegativity, boundedness of solutions, and global asymptotic stability of the system. By constructing suitable Lyapunov functionals and using the Lyapunov-La Salle invariance principle, the authors prove the global stability of the infected（endemic） equilibrium and the diseasefree equilibrium for time delays. The authors have proven that if the basic reproduction number R_0 is less than unity, then the disease-free equilibrium is globally asymptotically stable, and if R_0 is greater than unity, then the infected equilibrium is globally asymptotically stable. The results obtained show that the global dynamic behaviors of the model are completely determined by the basic reproduction number R_0 and that the time delay does not affect the global asymptotic properties of the model.
