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Purpose: To investigate the effect of pyrimidine-thioindole on gastric cancer proliferation and the underlying mechanism of action. Methods: Cell viability and apoptosis were determined using MTT assay and Annexin V/PI assay, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was used for the determination of expression levels of miR-145, while protein expression levels were assayed by western blotting. Results: Pyrimidine-thioindole treatment significantly inhibited the proliferation of AGS and SNU-5 cells (p < 0.05), but had no effect on the viability of GES-1 cells. Exposure to pyrimidine-thioindole at doses of 8 and 10 µM significantly enhanced the apoptosis of AGS and SNU-5 cells (p < 0.05). Pyrimidinethioindole exposure markedly increased the proportions of AGS and SNU-5 cells in G1 phase (p < 0.05). In AGS and SNU-5 cell lines, pyrimidine-thioindole exposure at doses of 8 and 10 µM significantly upregulated the expression of miR-145, with higher enhancement of miR-145 expression in AGS cells than in SNU-5 cells. Moreover, pyrimidine-thioindole downregulated the expressions of MMP-2, MMP-9, c-Myc, p-PI3K and p-AKT in AGS and SNU-5 cells. Pyrimidine-thioindole treatment enhanced the expression of p21 in AGS and SNU-5 cells, relative to untreated cells (p < 0.05). Conclusion: These results suggest that pyrimidine-thioindole activates apoptotic signaling pathway, leading to reduction in cell proliferation and arrest of cell cycle. Moreover, it de-activates PI3K/AKT pathway and promotes miR-145 expression in AGS and SNU-5 cells. Thus, pyrimidine-thioindole has therapeutic significance for the management of gastric cancer. [ABSTRACT FROM AUTHOR]

The current study proposed an experimental investigation into the basic characteristics of solar thermal conversion using supercritical CO2-dimethyl ether (DME) natural convection. The main goals are to reduce the operation pressure while maintaining relative high solar thermal conversion efficiency. Experimental systems were established and tested in Shaoxing area (around N 30.0 deg, E 120.6 deg) of Zhejiang Province, China. Due to the preferable properties of supercritical fluids, very high Reynolds number natural convective flow can be achieved. Typical summer day results are presented and analyzed into detail in this paper. It is found that the introduction of DME has successfully reduced the operation pressure and the increase in DME fraction leads to further reduction. Different from pure supercritical CO2 systems, the collector pressure follows the trend of solar radiation with its peak value at noon, instead of continuously increasing mode. The mass flow rate and temperature are typically more stable and also more sensitive than pure supercritical CO2 tests due to the moderation of supercritical fluid properties when DME is introduced. At the same time, the averaged collector efficiency is less affected by the DME mass addition. It is also found that there possibly exist some optimal of DME mass fraction when both the system suitability and stable natural circulation can be achieved. [ABSTRACT FROM AUTHOR]