[Exhaust Emission Characteristics of Typical Alkanes from Heavy-Duty Diesel Vehicles Based on a Portable Emission Measurement System].

The on-road emissions of typical alkanes from 11 heavy-duty diesel vehicles with different emission standards (from China Ⅰ to China Ⅳ) were tested using a portable emission measurement system(PEMS) and quantified by gas chromatography-mass spectrometry (GC-MS). Our aim was to analyze the emission characteristics of typical alkanes in heavy-duty diesel vehicle exhaust. The results show that the emission standard significantly affected the emission factors (EFs) of n-alkanes and hopanes. Vehicles with higher emission standards had lower EFs. Compared with China Ⅰ vehicles, the total EFs of n-alkanes, 17α(H),21ß(H)-C30 hopane (C30-hopane), and 22S- and 22R-17α(H),21ß(H)-homohopane (22S-C31 and 22R-C31 homohopane) from China Ⅳ vehicles were significantly reduced by 72.23%, 64.95%, 70.78%, and 74.68%, respectively. The peak carbon numbers of gaseous n-alkanes were 17 to 18, while they were 18 to 21 in particulate n-alkanes. The 22S-C31 homohopane/(22S-C31 homohopane + 22R-C31 homohopane) ratios ranged from 0.46 to 0.56, with an average of 0.50, which conform to the characteristics of hopanes in petroleum. The total EFs of n-alkanes had a good linear relationship with the total EFs of C30-hopane, and the R2 was 0.9268. Furthermore, the driving conditions had a great influence on the emissions of n-alkanes and hopanes. Specifically, the EFs of n-alkanes and hopanes on non-highway roads were 1.69 to 2.42 times greater than those on highways.

Antitumor activity of adenoviral vector containing T42 and 4xT42 peptide gene through inducing apoptosis of tumor cells and suppressing angiogenesis.

The T42 peptide, generated from two active fragments of tumstatin, has been shown to have anti­tumor activity. The adenoviral vector is the most frequently used vector in research and clinical trials for gene therapy. In the present study, the anti­tumor activity of the T42 peptide and quadruple T42 (4xT42) peptide adenoviral vectors were elucidated for the first time, to the best of our knowledge. Human embryonic kidney 293 cells were infected with plasmid adenovirus (pAd)­enhanced green fluorescent protein (EGFP)­T42 or pAd­EGFP­4xT42 and the expression of the T42 and 4xT42 genes was confirmed by the identification of GFP expression and reverse transcription polymerase chain reaction experiments. The anti­cancer effects of pAd­EGFP­T42 and pAd­EGFP­4xT42 on breast cancer cells in vivo and in vitro were subsequently investigated. The results indicated that the packaging of the recombinant adenoviruses with the viral titer was successful, following purification at 5x109 plaque forming units/ml. The results also revealed that the recombinant adenoviruses promoted apoptosis in MCF­7 breast cancer cells and inhibited cancer growth. Through the analysis of caspase­3, B­cell lymphoma 2 (Bcl­2) and Bcl­2­associated X protein expression, it was demonstrated that the T42/4xT42 peptide may induce apoptosis via the mitochondrial pathway. In addition, mouse xenograft experiments confirmed that the T42 peptide inhibited tumor growth and reduced angiogenesis in vivo. In conclusion, the results of the present study indicated that the T42 and 4xT42 peptide genes, transfected by a recombinant adenovirus, may provide a potential novel strategy for the treatment of breast cancer.