Possible regulation of genes associated with intracellular signaling cascade in rat liver regeneration.

OBJECTIVE: The importance of signal transduction in cell activities has been generally accepted. The purpose of this study was to analyze the regulatory effect of intracellular signaling cascade-associated genes on rat liver regeneration (LR) at transcriptional level. MATERIAL AND METHODS: The associated genes were originally obtained through a search of the databases and related scientific publications; their expression profiles were then checked in rat LR using the Rat Genome 230 2.0 array. The LR-associated genes were identified by comparing the discrepancy in gene expression changes between the partial hepatectomy (PH) group and the sham operation (SO) group. RESULTS: A total of 566 genes associated with the intracellular signaling cascade were LR related. The genes involved in nine signaling pathways including intracellular receptor-, second messenger-, nitric oxide-, hormone-, carbohydrate-mediated, protein kinase, small GTPase, ER-nuclear and target of rapamycin (TOR) signaling pathways were detected to be enriched in a cluster characterized by up-regulated expression in LR. According to their expression similarity and time relevance, they were separately classified into 5 and 5 groups. CONCLUSIONS: It is presumed that following PH, the second messenger-mediated signaling pathway inhibits the inflammatory response, while the protein kinase cascade and small GTPase-mediated signal transduction stimulate the immune response; the intracellular receptor-, second messenger-, small GTPase-mediated signal transduction and protein kinase cascade coordinately control cell replication; the intracellular receptor-, second messenger-mediated and ER-nuclear signaling pathways facilitate cell differentiation; the MAPK cascade and small GTPase-mediated signal transduction play a role in cytoskeletal reconstruction and cell migration; the second messenger-, small GTPase-mediated and IkappaB kinase/NFkappaB cascades take care of protein transport, etc., in LR.

[Study on electro-degradation of new conjugated polymer PFO-BT15 light emitting diodes].

In the present paper electroluminescence spectrum and Raman spectrum were used to study electro-degradation of polymer light emitting devices (PLEDs) of PFO-BT15, a new and high-efficiency emitting polymer synthesized by the institute of polymer optoelectronic material & devices (IPOM) in South China University of Technology. The PLEDs with a configuration of ITO glass/PEDOT(120 nm)/PFO-BT15(80 nm)/Ba(4 nm)/Al(200 nm) emitted green light at 550 nm when 5 V dc voltage was applied. Three of those devices were used to study the electro-degradation mechanism of PLEDs. Device A was deposited in vacuum box in dark room to keep sample fresh; Device B was first lighted with current of 1 mA x 0.25 cm(-2) for 200 minutes, then with current of 5 mA x 0.25 cm(-2) for 60 minutes, finally with current of 10 mA x 0.25 cm(-2) for 40 minutes; Device C was lighted with current of 20 mA x 0.25 cm(-2) until the electroluminescence failure. Our experimental results indicate that the degradation speeds highly depend on the current through the devices. The stressed devices show the decrease in electroluminescence efficiency. However, the luminescence spectrum of the stressed device did not change compared with the fresh device, which suggest that the structure of the luminescent polymer did not change with the electro-stress. Raman spectrum was employed to probe the structure changes of the materials used in the device. We found that the PEDOT Raman peak disappeared andthe PFO-BT15 Raman peak still existed in electro-stress device. The results confirmed that it was the breakage of the PEDOT layer instead of degradation of emitting polymer, that led to the final failure of the PLEDs device. This work gives some valuable information for the design and development of highly stable organic light-emitting device.

[Spatiotemporal Dynamics of CO2 Emissions in Chongqing: An Empirical Analysis at the County Level].

China's CO2 emissions present obvious temporal and spatial distribution characteristics. Therefore, the study of spatiotemporal dynamics of CO2 emissions could provide useful information for the government and policy-makers on viable CO2 emissions mitigation in China. Using Chongqing as a case study, we investigated the spatiotemporal dynamics of CO2 emissions at the county level (38 counties) from 1997 to 2012.The mathematical statistical method, spatial autocorrelation, and rank size rule were employed to evaluate the CO2 emissions change in detail. The results showed that all of the counties in Chongqing have experienced a rapid growth of CO2 emissions, but the two dimensional structure of CO2 emissions has not changed. The Global Moran's I clearly decreases with a small fluctuation, and these values gradually decrease from 0.56 in 1997 to 0.40 in 2012.In addition, the HH clusters are concentrated in some counties in the downtown areas. Based on the rank size rule analysis, the slope values q decrease from -1.35 in 1997 to -0.88 in 2012, indicating a clear scattered pattern of CO2 emissions in Chongqing at the county level. It has also been proven that the proportion of second industries and the urbanization rate are more important impact factors for CO2 emissions than the population.