Immunogenicity evaluation of a DNA vaccine expressing the hepatitis C virus non-structural protein 2 gene in C57BL/6 Mice

Backgrounds: Most of the hepatitis C virus (HCV) infections elicit poor immune responses and 75% to 85% of cases become chronic; therefore, the development of an effective vaccine against HCV is of paramount importance. In this study, we aimed to evaluate co-administration of HCV non-Structural Protein 2 and IL-12 DNA vaccines in C57BL/6 mice. Methods: A plasmid encoding full-length HCV NS2 protein (non-structural protein 2) was generated and used to vaccinate mice. Negative control (an empty expression vector) was also employed to evaluate the background response. To investigate immune responses against vaccine, C57BL/6 mice received three doses of the vaccine with a two-week interval. Cellular immunity was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay for lymphocyte proliferation, lactate dehydrogenase release for cytotoxic T lymphocyte (CTL) activity and cytokine assay. Results: The findings demonstrated that immunization of mice with plasmid expressing HCV NS2 induced CTL response, interferon gamma production, and lymphocyte proliferation compared to negative control. The results also demonstrated that co-administration of IL-12 with the HCV NS2 plasmid induced significantly better immune response in C57BL/6 mice. Conclusion: DNA vaccine encoding HCV NS2 is an effective candidate that can trigger CTL-based immune response against HCV. In addition, the results suggested that combining the DNA vaccine approach with immune stimulatory cytokines may significantly enhance antigen-specific immune responses

Effect of splitter angles and orientations attached to pin fin on heat transfer and hydraulic characteristics in a jet impingement rectangular channel

Heat transfer improvement of heat sinks is very interesting in many applications including electronic devices cooling. In this study, the influence of rotational angle of splitters attached to pin fins for two cases of identical and opposite directions is investigated. Five angles including 0, 30, 45, 60 and 90 are considered in the analysis conducted for the rectangular channel. Air as the heat transfer fluid at 302 K and 35,000 Reynolds number enters the channel. The temperature of the bottom of the channel is assumed to be constant. 18 rows of circular pin fins on which splitters are attached for enhancement of heat transfer are examined. In the numerical analysis, Nusselt number, turbulent kinetic energy, friction factor and pressure drop are analyzed parameters. The simulation of the models presented in the current study is endeavored using ANSYS Fluent software, which employs finite volume method. Results revealed that, for the identical-direction case, as the angle rises, the average Nusselt number, turbulent kinetic energy, friction factor and pressure drop increase, in a way that for the case of 90 degree, Nusselt number is 9 % and turbulent kinetic energy is 96 % higher than the base case of zero angle. Moreover, friction factor and pressure drop of the vertical-splitter case are 4.8 and 4.6 times more than those of the base case. It is also concluded that increasing angle from 0 to 45° for the opposite-direction case, Nusselt number diminishes. However, extra increase in the angle from 45 to 90 degree results in Nusselt number enhancement. Similar trend of variation is also reported for turbulent kinetic energy. Results also indicated that for the opposite-direction case, friction factor and pressure drop rise; for the case of 90 degree, friction factor and pressure drop increase 4.4 and 4.32 times, respectively