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Both Streptococcus equi subsp. zooepidemicus (SEZ) and canine influenza virus (CIV) are two important pathogens causing infectious respiratory disease in dogs and are frequently codetected in respiratory secretions. However, the clinical significance of viral/bacterial coinfection remains unknown. This study investigated the pathogenic characteristics of infection with CIV and SEZ alone or in combination in mice. Our data indicated that the severity of the disease is related to the challenge order of CIV and SEZ. Coinfection of CIV and SEZ induced higher weight loss in mice than single infection, except for the VB group (viral followed by secondary bacterial infection). Compared with the concurrent or sequential infection groups of CIV and SEZ, mice in the CIV–SEZ preincubation group exhibited more obvious weight loss, higher mortality, and significantly enhanced burden of SEZ and CIV in tissues. Interestingly, viral and bacterial preincubation before coinfection caused typical pulmonary fibrosis in mice. Correspondingly, transforming growth factor (TGF)-β was upregulated, and its canonical small mother against decapentaplegic (Smad) 2/3 signaling was noticeably induced. Further investigation indicated that the activity of the viral neuraminidase (NA) enzyme upon sialic acid was considerably increased due to the direct interaction of CIV with SEZ, which may be related to the activation of the TGF-β signaling pathway. These findings implicate an unexpected contribution of the direct interaction between CIV and SEZ to synergistic pathogenicity. [ABSTRACT FROM AUTHOR]

Effects of nanosilica on cement hydration have been broadly investigated in the literature and early age cement hydration, as a whole, has been mainly considered, disregarding the substages of the hydration. The hydration of cement is characterized by different substages and nanosilica effect on the hydration could be a result of diverse, even contradictory, behavior of nanosilica in individual stages of the hydration. In this study, effects of nanosilica on different substages of cement hydration are investigated. Isothermal calorimetry results show that at early ages (initial 72 hours) the effects of nanosilica depend on the phenomenon by which the hydration is governed: when the hydration is chemically controlled, that is, during initial reaction, dormant period, and acceleratory period, the hydration rate is accelerated by adding nanosilica; when the hydration is governed by diffusion process, that is, during postacceleratory period, the hydration rate is decelerated by adding nanosilica. The Thermal Gravimetric Analysis on the samples at the hardened state (after 28 days of curing) reveals that, after adding nanosilica, the hydration degree slightly increased compared to the plain paste. [ABSTRACT FROM AUTHOR]