Aptamer has been long studied as a substitute of antibodies for many purposes. However, due to the exceeded length of the aptamers obtained in vitro, difficulties arise in its manipulation during its molecular conjugation on the matrix surfaces. Current study focuses on computational improvement for aptamers screening of hepatitis B surface antigen (HBsAg) through optimization of the length sequences obtained from SELEX. Three original aptamers with affinity against HBsAg were truncated into five short hairpin structured aptamers and their affinity against HBsAg was thoroughly studied by molecular docking, molecular dynamics (MD) simulation, and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) method. The result shows that truncated aptamers binding on HBsAg "a" determinant region are stabilized by the dynamic H-bond formation between the active binding residues and nucleotides. Amino acids residues with the highest hydrogen bonds hydrogen bond interactions with all five aptamers were determined as the active binding residues and further characterized. The computational prediction of complexes binding will include validations through experimental assays in future studies. Current study will improve the current in vitro aptamers by minimizing the aptamer length for its easy manipulation.
Carbon Fiber Reinforced Polymer (CFRP) was designed, simulated, and evaluated as a wrapping material on defected pipe using computational approach. This composite material was considered as a unique wrapping material as it may have the combined characteristics of the constituents or have substantially different properties than the individual constituents. Specifically, this research evaluates the capability of CFRP as a wrapper through SolidWorks Simulation using the static analysis, computational fluid dynamics analysis, and data analysis. This approach gives a preliminary consideration and justification on choosing the optimized lamination orientation of CFRP in real cases based on the simulated data. Various orientations were simulated and analyzed throughout this research. Based on all the simulation analysis, the CFRP wrapper with quasi-isotropic lamination with the 8 plies 45∘/90∘/0∘/45∘s orientation was seen most effective in reducing the stress and possess highest minimum safety factor at the fully defected region (100 × 100 × 7.11 mm thru) after the repair. Eventually, this optimized CFRP lamination orientation, proved that it was able to withstand pressures ranging between 0.86 to 19.6 MPa with a layer thickness in between 0.16 up to 3.76 mm. Based on the static analysis, this optimized laminated orientation of CFRP indeed showed that it was able to reduce the stress on an average of 94.10% after the repair was done. Relatively, CFRP was 0.2% higher in reducing the maximum stress at the defected region at the pipe, than the Glass Fiber Reinforced Polymer with the same orientation. Additionally, the flow simulation analysis in SolidWorks showed that fluid flow was undisrupted after the repair was done, and the wrapped region was resistant to any fluid leakages.