The transmission of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is associated with close contact to SARS patients and droplet secretions of those patients. The finding of positive RT-PCR results from stools of SARS patients suggests that stools of SARS patients or sewage containing stools of patients could transmit SARS-CoV. We used a novel style of electropositive filter media particle to concentrate the SARS-CoV from the sewage of two hospitals receiving SARS patients in Beijing. We also used cell culture, RT-PCR and gene sequencing to detect and identify the viruses from sewage. No infectious SARS-CoV contamination was found in any of the samples collected, but the nucleic acid of SARS-CoV could be detected in the sewage from the two hospitals before disinfection. While the RNA was only detected in three samples from the 309th Hospital, the others were negative after disinfection. These findings provide strong evidence that SARS-CoV can be excreted through the stool/urine of patients into sewage system, thus making the sewage system a possible route of transmission.

The aim of this paper is to study the dynamics of a new chronic HBV infection model that includes spatial diffusion, three time delays and a general incidence function. First, we analyze the well-posedness of the initial value problem of the model in the bounded domain. Then, we define a threshold parameter R 0 called the basic reproduction number and show that our model admits two possible equilibria, namely the infection-free equilibrium E 1 as well as the chronic infection equilibrium E 2. Further, by constructing two appropriate Lyapunov functionals, we prove that E 1 is globally asymptotically stable when R 0 < 1, corresponding to the viruses are cleared and the disease dies out; if R 0 > 1, then E 1 becomes unstable and the equilibrium point E 2 appears and is globally asymptotically stable, which means that the viruses persist in the host and the infection becomes chronic. An application is provided to confirm the main theoretical results. Additionally, it is worth saying that, our results suggest theoretically useful method to control HBV infection and these results can be applied to a variety of possible incidence functions presented in a series of other papers.

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Abstract. When exploiting large-scale ore-body, stability of panel pillars is the key to stability of structural support mechanical system of ore pillar-surrounding rock. It concerns the mining sequence of the ore-body, parameters of stope structure, and is a problem that must be considered to some mines of safety and economic exploitation. This paper applied numerical modeling and reliability analysis to study mechanical characteristics and the safety coefficients of antidumping and strength in the process of mine exploitation. And the size of panel pillars were determined synthetically, that provided technical support to the safe, economic and high-efficient mining.