High-throughput screening of SARS-CoV-2 main and papain-like protease inhibitors

The global COVID-19 coronavirus pandemic has infected over 109 million people, leading to over 2 million deaths up to date and still lacking of effective drugs for patient treatment. Here, we screened about 1.8 million small molecules against the main protease (Mpro) and papain like protease (PLpro), two major proteases in severe acute respiratory syndrome-coronavirus 2 genome, and identified 1851Mpro inhibitors and 205 PLpro inhibitors with low nmol/l activity of the best hits. Among these inhibitors, eight small molecules showed dual inhibition effects on both Mpro and PLpro, exhibiting potential as better candidates for COVID-19 treatment. The best inhibitors of each protease were tested in antiviral assay, with over 40% of Mpro inhibitors and over 20% of PLpro inhibitors showing high potency in viral inhibition with low cytotoxicity. The X-ray crystal structure of SARS-CoV-2 Mpro in complex with its potent inhibitor 4a was determined at 1.8 Å resolution. Together with docking assays, our results provide a comprehensive resource for future research on anti-SARS-CoV-2 drug development.

Comparison of fluor-mica glass-ceramics made by melt-casting and sintering methods / 实用口腔医学杂志

Objective: To study the effects of the melt casting and the sintering methods on the machinability and other characteristics of K_2O-MgO-MgF_2-SiO_2 glass-ceramics. Methods: X-ray diffraction(XRD) and scanning electron microscopy (SEM)were used to examine the main crystal and the microstructure of the glass ceramics of the same composition which were made by melt casting and sintering methods, respectively. The transmissivity, flexural strength and brittleness index were observed respectively. Results: The glass ceramics made by two different methods have the same crystal, KMg_(2.5)Si_4O_(10)F_2, while the specimen prepared by the sintering method had lower transmissivity,better machinability and mechanical properties due to the higher mica volume percent. Conclusion; For production of fluoro-mica glass ceramics, sintering method has superiority compared to melt-casting method.

Study on the chemical constituents of volatile oil from Radix Flemingiae Philippinensis / 中成药

Objective: To study the chemical constituents of volatile oil from Radix Flemingiae philippinensis. Methods: The oil was obtained by steam distillation. The chemical compositions were separated and identified by GC/MS. The relative contents in the oil were determined by area normalization method. Results: Thirty-nine compounds were gotten from Radix Flemingiae philippinensis. The compounds of its relative content that was more than 4% were as follows: ?-himachalene (1), ?-himachalene (2), ?-himachalene (3), ?-guaiene (4), Italicene (5). Conclusion: Volatile oil by steam distillation from Radix Flemingiae Philippinensis was separated and ideutified up to 80 percent in component analysis.