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RISS 인기검색어
- 검색키워드
- 저자 : Karevan, Mehdi (검색결과 5 건)
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Immunogenicity of glycine nanoparticles containing a chimeric antigen as Brucella vaccine candidate
Ghazal karevan,Kazem Ahmadi,Ramezan Ali Taheri,Mahdi Fasihi-Ramandi 대한백신학회 2021 Clinical and Experimental Vaccine Research Vol.10 No.1
Purpose: Brucellosis as a worldwide zoonotic illness affect domestic animals and humans doesn’t have any vaccine for the prevention of infection in humans yet. The aim of this study was to evaluate the specific immune response following the administration of glycine nanoparticles as adjuvant and delivery system of a chimeric antigen contained trigger factor, Omp31, and Bp26 in murine model. Materials and Methods: The chimeric antigen of Brucella was cloned and expressed in Escherichia coli (E. coli) BL21 (DE3). Purification and characterization of recombinant protein was conducted through Ni-NTA (nickel-nitrilotriacetic acid) agarose, SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis), and Western blot. Nanoparticle characteristics including morphology, particle size distribution, zeta potential, protein retention rate, and release rate were measured in vitro. Subsequently, nanoparticle contained antigen was administered to mice and blood sample was taken to measured the antibody level. Results: The protein retention in the nanoparticles was successfully done and the nanoparticle characteristics were appropriate. The average size of glycine particles containing antigen was about 174 nm, and the absorption of protein was approximately 61.27% of the initial value, with a release rate of approximately 70% after 8 hours. Enzyme-linked immunosorbent assay result proved that the immunized sera of mice which were administered with nano-formula contains high levels of antibodies (immunoglobulin G) against recombinant chimeric antigen and also a high level of mucosal antibody (immunoglobulin A) in the oral group, which showed a desirable immunity against Brucella. Conclusion: The results showed that chimeric antigen-loaded glycine nanoparticles can act as a vaccine candidate for inducing the cellular and humoral immune response against brucellosis.
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Mehdi Karevan,Raghuram V. Pucha,Md.A. Bhuiyan,Kyriaki Kalaitzidou 한국탄소학회 2010 Carbon Letters Vol.11 No.4
This study investigates the effect of filler content (wt%), presence of interphase and agglomerates on the effective Young's modulus of polypropylene (PP) based nanocomposites reinforced with exfoliated graphite nanoplatelets (xGnPTM) and carbon nanotubes (CNTs). The Young's modulus of the composites is determined using tensile testing based on ASTM D638. The reinforcement/polymer interphase is characterized in terms of width and mechanical properties using atomic force microscopy which is also used to investigate the presence and size of agglomerates. It is found that the interphase has an average width of ~30 nm and modulus in the range of 5 to 12 GPa. The Halpin-Tsai micromechanical model is modified to account for the effect of interphase and filler agglomerates and the model predictions for the effective modulus of the composites are compared to the experimental data. The presented results highlight the need of considering various experimentally observed filler characteristics such as agglomerate size and aspect ratio and presence and properties of interphase in the micromechanical models in order to develop better design tools to fabricate multifunctional polymer nanocomposites with engineered properties.
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Mohammad Nematollahi,Mehdi Karevan,Marzieh Fallah,Mahmoud Farzin 한국섬유공학회 2020 Fibers and polymers Vol.21 No.4
Widespread attention to make use of biodegradable resources as a replacement for petroleum products leads to theexploitation of natural fiber reinforced composites. Natural fiber reinforced polymer composites usually exhibit lowermechanical properties than synthetic fiber ones. Thus, understanding key factors affecting the overall mechanical propertiesin order to increase them is crucial. One underlying factor is the length of fiber highly contributing to the extent of matrix/fiber interfacial load transfer at the interface. However, the concurrent examination of the load transfer mechanism at theinterface of fiber/matrix in terms of fiber length has not been well performed using computational, analytical andexperimental approaches. This work is aimed at the determination of the critical fiber length associated with a full loadtransfer condition using various methods to better understand their accuracy and the interfacial load transfer mechanism. Forthis purpose, specimens of neat polypropylene (PP) and 20 wt% kenaf/PP composites were fabricated using extrusioninjection molding. Tensile testing, scanning electron microscopy and density measurements were conducted to incorporatethe obtained results into the models and to verify the results predicted by the models. A three dimensional representativevolume element (RVE) representing the filler content of fabricated specimens was assumed. A micromechanical model wasemployed to make the results of analysis independent of the RVE dimensions. The critical fiber length for a full load transferwas determined by evaluating the stored elastic strain energy changes against the fiber length. The results showed that thekenaf fiber length is critical to both the load transfer efficiency and stiffening of composites. The results further revealed thatto obtain the full interfacial load transfer, the length of kenaf fibers needs to be greater than the critical length being ~2.4 mmprovided that perfect kenaf/PP interfacial interaction exists.
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Shaun Eshraghi,Suman Das,Mehdi Karevan,Kyriaki Kalaitzidou 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Electrically conductive polymer nanocomposites were prepared through selective laser sintering (SLS) of polyamide-12 (PA) powder coated with graphite nanoplatelets (GNP) using sonication. The SLS process parameters were optimized in order to maximize the tensile modulus at 3 and 5 wt% GNP. The highest tensile modulus (2.1 GPa) was achieved at 3 wt%. A slight decrease in flexural modulus and strength was observed at 3 and 5 wt% GNP compared with the neat polymer. Morphological observation of the graphitecoated PA powder showed fairly homogeneous dispersion. The SLS processed parts were nearly fully dense and the highest density (99.5%) was found at 3 wt% GNP. The bulk electrical conductivity of the SLS-processed nanocomposites was found to be 3.8×10-11 and 6.4×10-8 S/cm for 3 and 5 wt% GNP respectively.
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