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The delayed predator–prey system with generalized non-monotonic functional responses and stage structure was investigated in the present paper. By virtue of Mawhin's coincidence degree and the application of inequalities technique, we are successful to generate some novel conditions to guarantee that the system has at least two positive periodic solutions. It is shown that all parameters of the system have effects on the existence of positive periodic solutions and the period of the coefficients can also affect the existence of positive periodic solutions. In the end, an illustrative example is presented to the feasibility of the main results. [ABSTRACT FROM AUTHOR]

The stability of a new two-species discrete ratio-dependent predator-prey system is considered. By using the linearization method, we obtain some sufficient conditions for the local stability of the positive equilibria. We also obtain a new sufficient condition to ensure that the positive equilibrium is globally asymptotically stable by using an iteration scheme and the comparison principle of difference equations, which generalizes what paper (Chen and Zhou in J Math Anal Appl 27:7358-7366, 2003) has done. The method given in this paper is new and very resultful comparing with articles (Damgaard in J Theor Biol 227:197-203, 2004; Edmunds in Theor Popul Biol 72:379-388, 2007; Fan and Wang in Math Comput Model 35:951-961, 2002; Muroya in J Math Anal Appl 330:24-33, 2007; Huo and Li in Appl Math Comput 153:337-351, 2004; Liao et al. in Appl Math Comput 190:500-509, 2007) and it can also be applied to study other global asymptotic stability for general multiple species discrete population systems. At the end of this paper, we present two open questions. [ABSTRACT FROM AUTHOR]

Ribavirin is a broad-spectrum antiviral agent that is used against RNA and DNA viruses and has been reported to inhibit infection by influenza A and B virus in vitro and in vivo. Studies have shown that ribavirin can lower convalescent antibody titers in young children hospitalized with influenza. Here, we report that ribavirin administration in juvenile mice significantly attenuated respiratory immune responses, production of total IgA and hemagglutinin (HA)-specific secretory IgA responses on the mucosal surface. In contrast, systemic IgG and IgA responses were not affected. Ribavirin significantly suppressed toll-like receptor 2 and 4 expression in the lung and decreased the level of IL-1β, IL-6, TNF-α, and IFN-γ in lung tissues of mice infected with influenza virus. Our findings suggest ribavirin appears to be able to inhibit viral replication and, as a result, TLR and cytokine expression are not up-regulated, attenuating inflammation as well as the respiratory tract's immune response. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of Chinese medicine Haoqin Qingdan Decoction (蒿芩清胆汤, HQD) for febrile disease dampness-heat syndrome (FDDHS). Methods: Forty mice were divided into four groups, including normal control, FDDHS (induced by Radix et Rhizoma Rhei recipe and influenza virus A1 FM1 model), HQD, and the ribavirin groups (10 in each). The normal control and FDDHS groups were administered normal saline. HQD and the ribavirin groups were administered HQD and ribavirin intragastrically once daily at a dose of 64 g/(kg d) and 0.07 g/(kg d), respectively for 7 days. Lethargy, rough hair, diarrhea, tongue color and sole color were evaluated for pathological changes in morphology. The tongue and lung tissues were collected for histology. The CD14 and toll-like receptor 4 (TLR4) expression levels were measured using real-time quantitative polymerase chain reaction. Results: More than 80% of the FDDHS mice showed hypokinesia and lethargy, and pathological changes associated with rough hair, diarrhea, tongue color and sole color. With advanced treatment for 7 days, the thick greasy tongue fur of the HQD and ribavirin groups were thinner than that of the FDDHS group ( P<0.05), and it was the thinnest in the ribavirin group as compared with that in other groups ( P<0.05). The CD14 and TLR4 expression levels in the lung tissues of HQD and ribavirin groups significantly delined compared with the model group ( P<0.05 or P<0.01). CD14 was down-regulated more remarkably in the HQD group compared with the ribavirin group ( P<0.05), whereas the converse was true with TLR4 ( P<0.05). Conclusions: We established a FDDHS mouse model showing systemic clinical symptoms. Both HQD and ribavirin can inhibit the expression of CD14 and TLR4 in FDDHS mice, while the effect of ribavirin might be much more violent. The expression changes of CD14 and TLR4 consistently refers to lipopolysaccharide, the commonly and hotly inducing factor in FDDHS. [ABSTRACT FROM AUTHOR]

Coker naphtha was separated into ten distillation fractions equal in volume via Engler distillation. It was found that the mercaptan sulphur compounds were mainly concentrated in the lighter fractions, whereas the basic nitrogen compounds were concentrated in the heavier fractions. The gum content increased gradually with increasing the boiling point of each fraction after storage for 21 days under ambient conditions (25◦C, 101 kPa). The active organic acidic compounds in coker naphtha extracted with aqueous solution of 20 mass % NaOH represented 0.26 mass %. The GCMS analysis of the active organic acidic compounds showed the amounts of small molecule thiols, thiophenols (including benzyl mercaptan) and phenolic compounds to be 2.6 %, 4.4 % and 90.0 %, respectively. After removal of the active acidic compounds by caustic scrubbing, the increase in the rate of gum formation was much slower than that of the blank coker naphtha after 27 days of storage under ambient conditions, indicating that the effect of these acidic compounds on the gum formation is more significant than with basic nitrogen compounds. It is demonstrated that the storage stability of coker naphtha was decreased in the presence of large amounts of phenolic compounds, which may accelerate the acid-catalysed polymerisation of olefins. [ABSTRACT FROM AUTHOR]

Finite-frequency travel time tomography is a newly developing method. The main procedure in this new method is to compute the traveltime sensitive kernel. The travel time of the same scatterer needs to be used for computing the traveltime sensitive kernel many times. It is a time-consuming task. It is easy and fast to get the travel time from analytic equations in a simple model such as a homogenous or linear velocity media. However, most of the earth models are layered. It is cumbersome to get the travel time from analytic equations. In order to enhance the computation efficiency, we used the table look-up method to compute the finite-frequency travel time sensitive kernel for P-waves in a layered structure model. We chose the AK135 earth model for the velocity model. The table look-up method saved about 50% of the computation time. We enhanced the computation speed by using the table lookup method in the same velocity model, which was very useful for enhancing the computation efficiency for the finite-frequency travel time tomography. [ABSTRACT FROM AUTHOR]