No abstract

Interferon alpha (IFN-α) therapy is widely used to treat patients with chronic hepatitis B (CHB) but the sustained response rate is low, and the molecular mechanisms for the ineffectiveness of IFN-α treatments are not known. We screened differentially expressed genes between responders (Rs) and nonresponders (NRs) in patients with CHB treated with IFN-α to explore the molecular basis for treatment failure. Expression profiling was performed on percutaneous needle liver biopsy specimens taken before therapy. Gene expression levels were compared between seven patients who did not respond to therapy (NR) and six who did respond (R). Gene ontology category and KEGG pathway were analysed for differentially expressed genes, and the selected differentially expressed genes were confirmed using real-time polymerase chain reaction. We identified 3592 genes whose expression levels differed significantly between all Rs and NRs (P < 0.05); many of these genes are IFN-stimulated genes (ISGs) and immune-related genes. The ISGs were more highly expressed, while immune-related genes were inhibited in NRs before IFN-α treatment. Two ISGs (CEB1 and USP18) that are linked in an IFN inhibitory pathway are highly expressed in NRs, and a potential antiviral gene ISG20 was inhibited in NRs, suggesting a possible rationale for treatment nonresponse. Patients who do or do not respond to IFN have different liver gene expression profiles before IFN-α treatment. Preactivation of the IFN signalling pathway leading to the increased expression of inhibitory ISGs and inhibition of immune response in the pretreatment livers was associated with treatment failure.

Thermal spray torches commonly use argon for plasma generation. Low thermal properties of argon, however, limit the thermal efficiency of the torches. Use of molecular gases, which must dissociate before ionization, requires larger energy input resulting in enthalpy increase of the plasma. In this paper, the effect of various gas compositions (Ar, Ar+H2, and CO2+CH4) on the torch voltage-current characteristics, power and thermal efficiency were studied. At the same time, in-flight YSZ particle conditions were compared. The higher thermal conductivity and efficiency of CH4+CO2 gas mixture produce more favorable sprayed particle conditions, in particular temperature. At a 50mm spray distance, YSZ particle temperatures were 2470°C and 2896°C for Ar+H2 and CH4+CO2, respectively. Typical arc voltage for the torch operating in CO2+CH4 was 130-180V compared to 45-60 V for Ar+H2. Thermal efficiency was also 20-40% higher.

Compared to argon, plasmas generated by molecular gases and operated at the same electric current level contain much higher enthalpy. This is because molecular gases must dissociate before ionization, which requires larger energy input. The authors have developed a new DC plasma torch, which operates with a mixture of carbon dioxide (CO 2 ) and methane (CH 4 ). The torch was employed for plasma spray coating with input power in a range of 30 to 45 kW. This paper reports on the effect of CO 2 /CH 4 mixtures on the particle conditions during spraying of nickel alloy powders. Results of gas composition analysis at various distances from the nozzle exit are presented. The particle in-flight conditions, coating microstructure, and deposition efficiency are analyzed.