In this paper, an impulsive synchronisation scheme for a class of fractional-order hyperchaotic systems is proposed. The sufficient conditions of a class of integral-order hyperchaotic systems' impulsive synchronisation are illustrated. Furthermore, we apply the sufficient conditions to a class of fractional-order hyperchaotic systems and well achieve impulsive synchronisation of these fractional-order hyperchaotic systems, thereby extending the applicable scope of impulsive synchronisation. Numerical simulations further demonstrate the feasibility and effectiveness of the proposed scheme.
Short-chain prenyltransferases are responsible for biosynthesis of the C(10)-C(20) precursors of a variety of isoprenoids. We previously isolated two different short-chain prenyltransferases from the green peach aphid, Myzus persicae (MpIPPS1 and MpIPPS2). In this study, the activity of the two aphid prenyltransferases was analyzed in vitro. Kinetic analysis using recombinant enzymes showed that both prenyltransferases could efficiently catalyze the formation of C(10) geranyl diphosphate (GPP) and C(15) farnesyl diphosphate (FPP) from the C(5) substrates isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), and MpIPPS2 had higher catalytic activity than MpIPPS1. Product analysis by gas chromatography-mass spectrometry demonstrated that FPP was generated as the major product, but GPP could be detected at low enzyme concentrations. Molecular docking revealed that MpIPPS2 had higher binding affinity with the substrates DMAPP, IPP, and GPP than MpIPPS1, which supported the experimentally determined kinetic parameters. Molecular docking also identified an amino acid residue (K266) critical to the catalytic activity of both MpIPPS1 and MpIPPS2. This prediction was subsequently confirmed by site-directed mutagenesis, in which a point mutation (K266I) abolished the activity of both MpIPPS1 and MpIPPS2. Our data illustrate that both aphid short-chain prenyltransferases are active forms, which is in contrast to the previously reported results.
BackgroundThe prognosis of patients with advanced gastric cancer is poor. The goal of this study was to evaluate the efficacy and safety of combination therapy of cetuximab and S-1 combined with oxaliplatin (SOX) in Chinese patients with advanced gastric cancer.MethodsFor patients in the experimental group (cetuximab in combination with SOX (Ce-SOX), 30 patients), once-weekly cetuximab (400 mg/m2 at the first infusion then 250 mg/m2 every week) was administered. For patients in both the control (SOX alone, 26 patients) and experimental groups, oxaliplatin (100 mg/m2) was administered intravenously on day 1, while S-1 (80 mg/m2/day) was given orally twice daily for 14 days. The endpoints of this study included progression-free survival, response rate, and disease-control rate.ResultsThere was no statistically significant difference in response rate between the Ce-SOX and SOX groups (54.8% versus 44%, P = 0.225). The difference in disease-control rate was also statistically insignificant between the two groups (87.1% versus 76%, P = 0.162). Median progression-free survival in the Ce-SOX group was significantly higher than that in the SOX group (12.8 versus 10.1 months, P = 0.007). The median overall survival of the Ce-SOX group and SOX group was 14.0 and 12.2 months, respectively (P = 0.043). The one-year survival rate for the Ce-SOX group was 57% compared to 40% in the SOX group. There was no statistical difference in the grade 3 or 4 adverse effects between the two groups.ConclusionsThese findings suggest that the cetuximab combined with SOX regimen is feasible and shows promising efficacy with tolerable adverse effects in Chinese patients with advanced gastric cancer.
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