RESUMEN
In this study, a stochastic SIRS epidemic model that features constant immigration and general incidence rate is investigated. Our findings show that the dynamical behaviors of the stochastic system can be predicted using the stochastic threshold $ R_0^S $. If $ R_0^S < 1 $, the disease will become extinct with certainty, given additional conditions. Conversely, if $ R_0^S > 1 $, the disease has the potential to persist. Moreover, the necessary conditions for the existence of the stationary distribution of positive solution in the event of disease persistence is determined. Our theoretical findings are validated through numerical simulations.
Asunto(s)
Modelos Biológicos , Síndrome de Respuesta Inflamatoria Sistémica , Humanos , Síndrome de Respuesta Inflamatoria Sistémica/epidemiología , Simulación por Computador , Procesos EstocásticosRESUMEN
On the reported TCP-OH (See Schemeâ 1), other two star-shaped molecules are theoretically designed by replacement of side group of TCP-OH by N,N-di(4-methoxyphenyl)aniline for TPAP-OH and oxygen-bridged triarylamine for TBOPP-OH. The core group, phenol, is kept in three molecules. Their potential to be hole transport material in perovskite solar cells without dopants is evaluated by multiscale simulations. The properties of isolated molecules are estimated by the frontier molecular orbital, absorption spectrum, and hole mobility. After that, the HTM@CH3 NH3 PbI3 adsorbed system is studied to consider the influence of adsorption on HTM performance. Besides the primary judgment, the glass transition temperature is also simulated to determine the stability of amorphous film. Not only the chemical stability is evaluated but also the amorphous film stability is considered. The latter is almost neglected in previous theoretical studies to evaluate the properties of HTMs. The performance of a designed molecule is evaluated from both the isolated molecules and HTM@CH3 NH3 PbI3 adsorbed system including aforementioned items, which is favorable to build reliable structure-property relationship.
RESUMEN
Efficiency of non-viral gene delivery based on chitosan and chitosan derivatives as DNA condensing carrier is dependent on a series of factors, such as complex size, the charge ratio of chitosan/DNA, molecular mass of chitosan, the degree of chitosan deacetylation, pH and serum concentration of the transfection medium. Through modifying the chitosan in a certain extent, we can change the efficiency of transfection. Studies on transfection condition, efficiency and mechanism using chitosan and chitosan derivatives as transfection agents are reviewed.