Abstract: Contrary to the traditional economic prediction that prices decrease as more firms enter the market, this paper finds a non-monotonic relationship between the number of firms and prices in online book markets. A substantial decrease in posted prices is observed when the market moves from a monopoly to duopoly. Surprisingly, as the market further expands, posted prices converge to monopoly price rather than competitive price. This is because as the number of sellers increase on the internet, the cost for consumers to obtain accurate information as well as the cost to evaluate products and sellers increase. Thus, the existence of a large number of sellers deter consumer search and lead to more random purchases. With little consumer search, sellers’ returns to undercutting price reduce. Therefore, instead of lowering price when faced with more competitors, sellers increase prices.

Cuscuta chinensis Lam. (Convolvulaceae) is an important herbal medicine widely used to improve sexual function, treat osteoporosis, and prevent aging, and has been reported to exhibit anti-osteoporotic effects in vitro. However, the activity of Cuscuta chinensis Lam. on glucocorticoid-induced osteoporosis still remains unclear. The present study aimed to assess the protective effect and the underlying mechanism of action of Cuscuta chinensis extract (CCE) against glucocorticoid-induced osteoporosis in vivo. Sprague-Dawley rats were randomly divided into four groups as follows: control group, osteoporosis group, and 2 CCE-treated osteoporosis groups (100 mg·kg-1·day-1). Blood samples and femur bones were collected for immunohistochemistry, biochemical, mRNA expression, and western blot analysis. HPLC analysis revealed that chlorogenic acid, quercetin, and hyperin were the major constituents of CCE. The results indicated that CCE increased bone length, bone weight, and bone mineral density and suppressed dexamethasone (DEX)-induced reduction in body weight. In addition, TRAP staining indicated that CCE reduced osteoclasts in DEX-induced osteoporosis rats. Mechanistically, CCE treatment alleviated the increase of bone resorption markers and the decline of osteogenic markers, which might be partially mediated by regulation of RANKL/OPG and RunX2 pathways. These results suggest that CCE showed promising effects in the protection against glucocorticoid-induced osteoporosis through protecting osteoblasts and suppressing osteoclastogenesis.

Abstract: The eBooks market has been growing rapidly in recent years. At the same time, evidence shows that eBooks are cannibalizing the market for physical books. To alleviate the cannibalization effect between eBooks and physical books, publishers may choose to delay the release of eBooks or physical books for a period of time. Adopting a stylized two-period model, this paper investigates three publishing strategies for a monopolistic publisher: delaying the release of eBooks, delaying the release of physical books, and releasing them simultaneously. We find that the publisher should delay the format that has significantly less market potential. Furthermore, the one that has greater market potential should be priced higher. In addition, a stronger substitution effect between eBooks and physical books favors delaying strategies. Finally, the smaller marginal cost for eBooks than physical books renders the strategy to delay the release of physical books more popular.

We wish to report a set of seventeen ketones bearing nabumetone and trifluoro- methylaniline(TFMA) moieties. Synthesized via direct Mannich reaction in a solution of ethanol- chloroform catalyzed by concentrated hydrochloric acid, the chemical structures of these compounds were characterized by IR, ¹H NMR, 13C NMR, ESI MS and HR MS. Studies on their antidiabetic activities revealed that all title compounds possessed moderate α-glucosidase inhibitory activities and protein tyrosine phosphatase 1B (PTP 1B) inhibitory activities. Among them, a few compounds also exhibit considerable peroxisome proliferator-activated receptor response element (PPRE) agonist activity, in particular the relative PPRE agonist activity of compounds 1r and 1l reached 54.02% and 57.60%, respectively. These results represent significant examples of new molecular type for antidiabetic agents that merit further evaluation.

Rapid detection of Mycobacterium tuberculosis complex (MTBC) is a critical step in controlling tuberculosis (TB). In this study, we used IS6110 as the specific identification target to develop a novel hybridization signal amplification method (HSAM) for the rapid and direct detection of MTBC from clinical sputum specimens. This system consists of magnetic bead-linked capture probes for target isolation, dextranbased nanoparticles for amplifying the reporter molecule (biotinylated-FITC), and detection probes (2B-DNA) for binding the nanoparticles. Both the capture and detection probes were specific to the IS6110 target sequence. Our results determined that as few as 10 copies of the IS6110 sequence or 10 M. tuberculosis bacteria could be detected, indicating that the HSAM assay is as sensitive as conventional PCR, and the assay was specific enough to distinguish MTBC from nontuberculosis mycobacteria (NTM). A total of 176 clinical sputum specimens were collected for HSAM evaluation, and the results were compared to those from traditional culture and biochemical identification techniques. This assay had a sensitivity of 88.3%, a specificity of 91.8%, a positive predictive value of 93.8% and a negative predictive value of 84.8% for the detection of MTBC. This technique is highly sensitive and specific, is easy to perform, and does not require any sophisticated detection equipment; thus, this approach has great potential in clinical TB detection and diagnostic applications.

In this paper, the generalized anti-reflexive solution for matrix equations (BX = C, XD = E), which arise in left and right inverse eigenpairs problem, is considered. With the special properties of generalized anti-reflexive matrices, the necessary and sufficient conditions for the solvability and a general expression of the solution are obtained. Furthermore, the related optimal approximation problem to a given matrix over the solution set is solved. In addition, the algorithm and the example to obtain the unique optimal approximation solution are given.