Search

The initiation processes of one of the initial convective cells near and on the east side of a dryline on 19 June 2002 during the IHOP_2002 field experiment in the central United States is analyzed in detail based on a high-resolution numerical simulation. Prominent horizontal convective rolls and associated near-surface moisture convergence bands [called roll convergence bands (RCBs) here] develop within the convective boundary layer (CBL) due to surface heating, in the hours leading to convective initiation (CI). The RCBs east of the dryline are advected toward the primary dryline convergence boundary (PDCB) by the southerly moist flow as the CBL deepens with time. Backward trajectories of air parcels forming the initial precipitating updraft of the convective cell are found to primarily originate at about 1-1.5 km above ground, within the upper portion of the shallower CBL earlier on. The representative air parcel is found to follow and stay on top of a surface RCB as the RCB moves toward the PDCB, but the RCB forcing alone is not enough to initiate convection. As this RCB gets close to the PDCB, it moves into a zone of mesoscale convergence and a deeper CBL that exhibits an upward moisture bulge associated with the PDCB. The combined upward forcing of the RCB and the mesoscale PDCB convergence quickly lifts the representative air parcel above its level of free convection to initiate convection. A conceptual model summarizing the CI processes is proposed. [ABSTRACT FROM AUTHOR]

Chemically synthetic siRNA and miRNA have become powerful tools to study gene function in the past decade. Fluorescent dyes covalently attached to the 5′ or 3′ ends of synthetic small RNAs are widely used for fluorescently imaging and detection of these RNAs. However, the reliability of fluorescent tags as small RNA markers in different conditions has not attracted enough attention. We used Cy3-labelled small RNAs to explore the reliability of fluorescent tags as small RNA markers in cell cultures involving serum. A strong Cy3-fluorescence signal was observed in the cytoplasm of the cells transfected with Cy3-miR24 in the culture medium containing fetal bovine serum (FBS), but qRT-PCR results showed that little miR24 were detected in these cells. Further study demonstrated that small RNAs were degraded in the presence of FBS, suggesting that it was Cy3-RNA fragments, rather than the original Cy3-miR24, diffused into cells. These phenomena disappeared when FBS was replaced by boiled-FBS, further supporting that the Cy3-fluorescence we observed in cells in the presence of FBS could not represent the presence of intact small RNAs. These findings addressed that fluorescent tags are not reliable for small RNA transfection in the presence of serum in culture. [ABSTRACT FROM AUTHOR]

Gemcitabine (GEM), as an anti-metabolic nucleoside analog, has been shown to have anticancer effects in various tumors, but its chemotherapy resistance is still an important factor leading to poor prognosis of cancer patient. A large number of studies in recent years have shown that autophagy plays an important role in the chemotherapy sensitivity of many tumors, including pancreatic, non-small cell lung, and bladder cancer. However, whether GEM causes autophagy in gallbladder cancer (GBC) and whether it is related to chemotherapy resistance is unknown. In the present study, we demonstrated that GEM induced apoptosis and protective autophagy in GBC cells, which may be related to the AKT/mTOR signaling pathway, and GEM in combination with autophagy inhibitor chloroquine can strengthen the cytotoxic effect of GEM on GBC in vitro and in vivo. These findings showed that both autophagy and AKT/mTOR signals were engaged in GBC cell death evoked by GEM, GBC patients might benefit from this new treatment strategy, and molecular targeted treatment in combination with autophagy inhibitors shows promise as a treatment improvement. [ABSTRACT FROM AUTHOR]