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A series of 6-acetyl-coumarin derivatives (2a-n) were synthesized and evaluated for antiretroviral activity in C8166 T-cell line infected with HxBru-Gluc strain of human immunodeficiency virus-1. Michael Addition followed by re-aromatization and subsequent acid-induced elimination of water leads to the formation of coumarin intermediate, which undergoes Claisen-Schmidt condensation with substituted bezaldehydes using silica sulphuric acid as a catalyst to form 6-acetyl-coumarin derivatives, 2a-n. In silico absorption, distribution, metabolism, excretion and toxicity parameters of compounds 2a-n were found within their reference limits. All synthesized compounds were devoid of cytotoxicity as they have shown cell viability count more than 80 % in cytotoxicity assay. Compounds 2a, 2g and 2h showed potent inhibitory activity against human immunodeficiency virus infection with IC50 value of 4.7, 4.5 and 0.35 μM, respectively. It was found that electron-withdrawing group at phenyl ring, attached to the coumarin nucleus was crucial for activity against human immunodeficiency virus. The present study may be helpful in the development of some potent antiretroviral agents.

Degradation of scaffolds is an important problem in tissue regeneration management. This paper reports a comparative study on degradation of the printed 3D poly (lactic-co-glycolic acid) scaffold under three conditions, namely, micro-channel, incubator static, and incubator shaking in the phosphate buffer saline (PBS) solution. In the case of the micro-channel condition, the solution was circulated. The following attributes of the scaffold and the solution were measured, including the mass or weight loss, water uptake, morphological and structural changes, and porosity change of the scaffold and the pH value of the PBS solution. In addition, shear stress in the scaffold under the micro-channel condition at the initial time was calculated with Computational Fluid Dynamics (CFD) to see how the shear stress factor may affect the morphological change of the scaffold. The results showed that the aforementioned attributes in the condition of the micro-channel were significantly different from the other two conditions. The mechanisms that account for the results were proposed. The reasons behind the results were explored. The main contributions of the study were (1) new observations of the degradation behavior of the scaffold under the micro-channel condition compared with the conditions of incubator static and incubator shaking along with underlying reasons, (2) new understanding of the role of the shear stress in the scaffold under the condition of the micro-channel to the morphological change of the scaffold, and (3) new understanding of interactions among the attributes pertinent to scaffold degradation, such as weight loss, water uptake, pH value, porosity change, and morphological change. This study sheds important light on the scaffold degradation to be controlled more precisely.