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Enterohaemorrhagic E. coli (EHEC) is a type of human pathogenic bacteria. The main virulence characteristics of EHEC include the formation of attaching and effacing lesions (A/E lesions) and the production of one or more Shiga-like toxins, which may induce human uremic complications. When EHEC infects host cells, it releases translocated intimin receptor (Tir) and effector proteins inside the host cells, inducing the rearrangement and accumulation of the F-actin cytoskeleton, a phenotype leading to the formation of pedestals in the apical cell surface, and the growth of stress fibers at the base of the cells. To examine the effect of EHEC infection on cell mechanics, we carried out a series of experiments to examine HeLa cells with and without EHEC infection to quantify the changes in (1) focal adhesion area, visualized by anti-vinculin staining; (2) the distribution and orientation of stress fibers; and (3) the intracellular viscoelasticity, via directional video particle tracking microrheology. Our results indicated that in EHEC-infected HeLa cells, the focal adhesion area increased and the actin stress fibers became thicker and more aligned. The cytoskeletal reorganization induced by EHEC infection mediated a dramatic increase in the cytoplasmic elastic shear modulus of the infected cells, and a transition in the viscoelastic behavior of the cells from viscous-like to elastic-like. These changes in mechanobiological characteristics might modulate the attachments between EHEC and the host cell to withstand exfoliation, and between the host cell and the extracellular matrix, and might also alter epithelial integrity.

In the real market, competition is becoming more intense. Companies must create customer value. They must also clearly and persuasively communicate that value to target customers. In practice, advertisement plays a key role in stimulating demand. This research incorporates the frequency of advertisement into the demand function. In order to develop and maintain a competitive advantage, the retailer offers an appreciation period in which customers can ask to return products for any reason. In addition, by providing advance sales, retailers extend the sales period and increase market share. In this article, we provide optimal ordering and advertisement policies for a two-warehouse inventory system with advance sales and product return guarantee. We first establish a proper model and then provide an easy-to-use method to obtain optimal ordering and advertisement policies for the retailer to achieve maximum total profit. Finally, numerical examples are given to illustrate the solution procedure, followed by a sensitivity analysis that examines the effect on the optimal solution of changes in the values of certain parameters. [ABSTRACT FROM AUTHOR]

Antioxidants contents and antioxidative enzymes and their activities in fresh aerial tissues of Hypericum sampsonii (Sampson’s St John’s Wort), Hypericum japonicum (Japanese St John’s Wort) and Hypericum perforatum were investigated. Hypericum sampsonii contained more total ascorbate [34.33 μmol g−1 fresh weight (FW)] than H. perforatum (57% less) and H. japonicum (82% less). It also contained more thiol and phenolics than two other species. Hypericum japonicum had highest superoxide dismutase (SOD) activity (8.74 mmol min−1 g−1 FW), followed by H. sampsonii (2% less) and H. perforatum (37% less). Hot-air dried H. perforatum materials contained more thiol [208.7 μmol g−1 dry weight (DW)] and phenolics (352.82 mg g−1 DW) than freeze-dried and fresh materials. Both drying treatments decreased the activities of antioxidative enzymes in aerial tissues of H. perforatum. However, freeze-dried H. perforatum contained the highest SOD activity (5.42 mmol min−1 g−1 DW) among the antioxidative enzymes measured from both freeze-dried and hot-air dried tissues (ranged from 0.02 to 2.65 μmol min−1 g−1 DW). [ABSTRACT FROM AUTHOR]