RESUMO
Prostate-specific antigen (PSA) serves as a critical biomarker for the early detection and continuous monitoring of prostate cancer. However, commercial PSA detection methods primarily rely on antigen-antibody interactions, leading to issues such as high costs, stringent storage requirements, and potential cross-reactivity due to PSA variant sequence homology. This study is dedicated to the precise design and synthesis of molecular entities tailored for binding with PSA. By employing a million-level virtual screening to obtain potential PSA compounds and effectively guiding the synthesis using machine learning methods, the resulting lead compounds exhibit significantly improved binding affinity compared to those developed before by researchers using high-throughput screening for PSA, substantially reducing screening and development costs. Unlike antibody detection, the design of these small molecules offers promising avenues for advancing prostate cancer diagnostics. Furthermore, this study establishes a systematic framework for the rapid development of customized ligands that precisely target specific protein entities.
RESUMO
The pollution characteristics and light extinction contribution of water-soluble ions of PM2.5 in Hangzhou were investigated by sampling and laboratory analysis of aerosol samplers in 2013. The water-soluble ions were dominant in PM2.5 and the total mass concentration was 37.5 µg·m-3, accounting for 44.4% of the PM2.5 mass concentration. Water-soluble ions were mainly composed of secondary ions(SO42-,NO3- and NH4+), which accounted for 83.4% of total ions. The highest mass concentrations of PM2.5 and major ions were observed in winter and the lowest in summer. The proportions of water-soluble ions in PM2.5 in summer and autumn were obviously higher than those in winter and spring and proportions of secondary ions in water-soluble ions were very close in each season. The contribution was the greatest to PM2.5 from secondary ions generation caused by fuel combustion and automobile exhaust. The annual average values of SOR and NOR were 0.27 and 0.15 respectively, the conversion rate of SO2 in atmosphere was greater than that of NOx. There was obvious positive correlation between SOR or NOR and humidity which indicated the important contribution of heterogeneous oxidation process to the generation of SO42- and NO3-. The annual average of[NO3-]/[SO42-] was 0.63, and the aerosol pollution was primarily affected by emissions from coal burning. In haze days, with the increase of haze pollution level, the mass concentrations of PM2.5, water-soluble ions, secondary ions as well as SOR and NOR all increased gradually, and the stable weather condition in haze days could efficiently promote the accumulation and secondary conversion of pollutants. There were obvious positive correlations between mass concentrations of PM2.5 and SNA and the atmospheric light extinction coefficient. The IMPROVE formula which was used to calculate the light extinction coefficients of different chemical components could efficiently indicate the tendency of aerosol scattering. The extinction contribution of SNA could reach 60.8%. The extinction coefficient of SNA was the highest in winter and lowest in summer, and its value and contribution proportion both increased gradually as the haze pollution level rose.