SPACECRAFT DOCKING SIMULATION USING HARDWARE-IN-THE-LOOP SIMULATOR WITH STEWART PLATFORM

A ground-based hardware-in-the-loop （HIL） simulation system with hydraulically driven Stewart platform for spacecraft docking simulation is presented. The system is used for simulating docking process of the on-orbit spacecraft. Principle and structure of the six-degree-of-freedom simulation system are introduced. The docking process dynamic of the vehicles is modeled. Experiment results and mathematical simulation data are compared to validating the simulation system. The comparisons of the results prove that the simulation system proposed can effectively simulate the on-orbit docking process of the spacecraft.

Pharmacotherapeutics and molecular docking studies of alphasynuclein modulators as promising therapeutics for Parkinson’s disease

Parkinson’s disease(PD)is an age-related neurodegenerative ailment that affects dopamine-producing neurons in a specific area of the brain called the substantia nigra of the ventral midbrain.It is clinically characterized by movement disorder and marked with unusual synaptic protein alpha-synuclein accumulation in the brain.To date,only a few Food and Drug Administration(FDA)approved drugs are available on the market for the treatment of PD.Nonetheless,these drugs show parasympathomimetic related adverse events and remarkably higher toxicity;hence,it is important to find more efficacious molecules to treat PD.In our study,We chosen 22 natural compounds as inhibitors that potentially block the alpha-synuclein clump-the pathological hallmark of PD-and provide new avenues for its treatment.Most of these molecules exhibited good pharmacokinetic behaviors,making them decisively favorable drug candidates to cure PD.Molecular docking studies were performed to investigate the binding interactions between natural compounds and alpha-synuclein as anti-Parkinson drug targets.Among the examined compounds,curcumin and piperine emerged as promising phytochemicals with the highest binding affinity,key residual stable bindings and showed a good inhibitory features.Thus,the present study indicates that curcumin and piperine hold the potential to be developed as treatment options against PD.Experimental validations are needed for insights into their mechanism of action and potential clinical application.

Discovery of Benzimidazole Derivatives as Novel Aldosterone Synthase Inhibitors:QSAR,Docking Studies,and Molecular Dynamics Simulation

Aldosterone synthase inhibitors can lessen the production of aldosterone in organisms,which effec-tively affecting the treatment of hypertension.A series of computational approaches like QSAR,docking,DFT and molecular dynamics simulation are applied on 40 benzimidazole derivatives of aldosterone synthase(CYP11B2)in-hibitors.Statistical parameters:Q^(2)=0.877,R^(2)=0.983(CoMFA)and Q^(2)=0.848,R^(2)=0.994(CoMSIA)indicate on good predictive power of both models and DFT’s result illustrates the stability of both models.Besides,Y-randomization test is also performed to ensure the robustness of the obtained 3D-QSAR models.Docking studies show inhibitors rely onπ-πinteraction with residues,such as Phe130,Ala313 and Phe481.Molecular dynamics simulation results further confirm that the hydrophobic interaction with proteins enhances the inhibitor’s inhibitory effect.Based on QSAR studies and molecular docking,we designed novel compounds with enhanced activity against aldosterone synthase.Furthermore,the newly designed compounds are analyzed for their ADMET proper-ties and drug likeness and the results show that they all have excellent bioavailability.

Designing Cyclopentapeptide Inhibitor of Neuraminidase H5N1 Virus Through Molecular and Pharmacology Simulations

Highly Pathogenic Avian Influenza（HPAI） H5N1 has attracted much attention as a potential pandemic virus in humans, which makes death inevitable in humans. Neuraminidase（NA） has an important role in viral replication. Thus, it is an attractive target when designing anti-influenza virus drug. However, evolving viruses cause some anti-viral drugs to be ineffective, as they show resistance to them. Selection of peptides as drug candidates is important for the peptide-receptor activity and good selectivity. Cyclic bonds in the peptide ligand design aim to improve the stability of the system and remove the obstacles in drug metabolism. The design is based on the polarity of the ligand and amino acid residues in the active site of NA. The results are 4200 cyclic pentapeptides as potential lead compounds. Docking simulations were conducted using MOE 2008.10 and were screened based on the value of the binding energy（？Gbinding）. ADME-Tox prediction assay was conducted on the selected ligands.Intra- and inter-molecular interactions, as well as changes in the form of bonds, were tested by molecular dynamics simulations at temperatures of 310 K and 312 K. The results of the docking simulations and toxicity prediction assay show that there are two ligands that have a residual interaction with the target protein： CLDRC and CIWRC. These two ligands have ？Gbindingvalues of –40.5854 and –39.9721 kcal/mol（1 kcal/mol = 4.18 k J/mol）. These ligands are prone to be mutagenic and carcinogenic, and they have a good oral bioavailability. The results show that the molecular dynamics of both ligand CLDRC and CIWRC are more feasible at the temperature of 312 K. At the end,both CIWRC and CLDRC ligands can be used as the drug candidates against H5N1 virus.