This study has identified a set of genes responsive to 0.5 Gy of gamma-rays. CDH6 gene can be specifically up-regulated by low dose irradiation, and its inducible expression could be involved in a low dose hypersensitive response.
Objective To investigate the impact of all-trans retinoic acid (ATRA) on MDM2 gene expression in astrocytoma cell line SHG-44, and to provide basic data for further research on the progression mechanism and gene therapy of human astrocytoma. Methods The differential expressions of MDM2 gene and protein in SHG-44 cells were detected by cDNA microarray and Western blot, respectively, before and after treatment of ATRA. The expressions of MDM2 protein in WHO grade II and grade IV astrocytomas were determined by immunohistochemical streptavidin-peroxidase method. Some differentially expressed genes were selected randomly for Northern blot analysis. Results The intensity ratio of ATRA-treated to untreated SHG-44 cell was 0.37 in the cDNA microarray, suggesting that the expression of MDM2 gene was down-regulated in SHG-44 cells after treatment with ATRA. Some genes differentially expressed in the microarray were confirmed by Northern blot. Western blot demonstrated that the optical density ratios of MDM2 to β-actin in ATRA-treated and untreated SHG-44 were 14.02±0.35 and 21.40±0.58 (t = 24.728, P = 0.000), respectively, suggesting that the expression of MDM2 protein was inhibited in ATRA-treated SHG-44 cells. Moreover, the percentages of MDM2-positive protein were 24.00% (6/25) and 56.52% (13/23) (χ 2 = 5.298, P = 0.021) in WHO grade II and grade IV astrocytomas, respectively, suggesting that the expression of MDM2 protein may increase along with the elevation of astrocytoma malignancy. Conclusion ATRA can inhibit MDM2 gene expression in SHG-44 cells, and MDM2 is related to astrocytoma progression.
Above ground petroleum product storage tanks are tanks or other containers that are above ground, partially buried, bunkered, or in a subterranean vault. These are built to store petroleum product for pipeline system, oilfield and refinery.
Tank fires are one of the most terrible accidents in oil pipeline transportation stations. Tank fires pose a significant hazard to people, buildings, process piping, the environment and other facilities as a result of thermal radiation exposure. It is necessary and meaningful to study the distribution of the thermal radiation of a tank fire for emergency response, prevention and reducing loss.
To analyze potential tank fire incidents at a pipeline station, a three-dimensional station model was built using a computational fluid dynamics (Abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows) software package to evaluate the thermal radiation distribution under different conditions. Numerical simulations were carried out for a total of six simulation scenarios to analyze 3 types of potential fires for 2 different liquid products (gasoline and diesel). The three kinds of fires that were modeled included: 1) disk pool fire on top of the tank; 2) ring pool fire on the top of a tank; and 3) pool fire in a dike. The simulation evaluates the effect of the thermal radiation on facilities and people.
The simulation results show that the water cooling system is effective at decreasing the magnitude of thermal radiation exposure and as a result is effective at protecting nearby tanks and facilities. Without water protection, the disk fire or ring fire can destroy or damage nearby structures significantly. The results of the simulation also show that the dike pool fire can have a catastrophic consequence to nearby facilities. Further the analysis showed that environmental wind does not change the thermal radiation distribution significantly. The results of the simulation point out countermeasure activities to enhance fire prevention at oil pipeline transportation stations in a scientific way.
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