Tetragonal CsPbBr nanosheets were obtained by an oriented attachment of orthorhombic CsPbBr nanocubes, involving a lateral shape evolution from octagonal to square. Meanwhile, the experimental results, together with DFT simulation results, indicated that the tetragonal CsPbBr is an indirect bandgap semiconductor that is PL-inactive with a bandgap of 2.979 eV.

Increasing evidence demonstrates that pyroptosis, pro-inflammatory programmed cell death, is linked to atherosclerosis; however, the underlying mechanisms remain to be elucidated. Dihydromyricetin (DHM), a natural flavonoid, was reported to exert anti-oxidative and anti-inflammatory bioactivities. However, the effect of DHM on atherosclerosis-related pyroptosis has not been studied. In the present study, palmitic acid (PA) treatment led to pyroptosis in human umbilical vein endothelial cells (HUVECs), as evidenced by caspase-1 activation, LDH release, and propidium iodide-positive staining; enhanced the maturation and release of proinflammatory cytokine IL-1β and activation of the NLRP3 inflammasome; and markedly increased intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS) levels. Moreover, NLRP3 siRNA transfection or treatment with inhibitors efficiently suppressed PA-induced pyroptosis, and pretreatment with total ROS scavenger or mtROS scavenger attenuated PA-induced NLRP3 inflammasome activation and subsequent pyroptosis. However, DHM pretreatment inhibited PA-induced pyroptotic cell death by increasing cell viability, decreasing LDH and IL-1β release, improving cell membrane integrity, and abolishing caspase-1 cleavage and subsequent IL-1β maturation. We also found that DHM pre-treatment remarkably reduced the levels of intracellular ROS and mtROS and activated the Nrf2 signaling pathway. Moreover, knockdown of Nrf2 by siRNA abrogated the inhibitory effects of DHM on ROS generation and subsequent PA-induced pyroptosis. Together, these results indicate that the Nrf2 signaling pathway plays a role, as least in part, in the DHM-mediated improvement in PA-induced pyroptosis in vascular endothelial cells, which implies the underlying medicinal value of DHM targeting immune/inflammatory-related diseases, such as atherosclerosis. © 2017 BioFactors, 44(2):123-136, 2018.

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Knowledge of the relative abundance of primary organic aerosol (POA) and secondary organic aerosol (SOA) forms an important scientific basis for formulating particulate matter (PM) control policies. Taking advantage of a comprehensive chemical composition data set of PM2.5 including both POA and SOA tracers (most notably, SOA tracers of a few biogenic voltaic organic compound precursors), we investigate the impact of inclusion of SOA tracers on the source apportionment of organic carbon (OC) and PM2.5 in the Pearl River Delta region of China using positive matrix factorization (PMF). In PMF runs incorporating SOA tracers (PMFw), ten PMF factors were resolved including four secondary factors: (1) SOA I (α-pinene, β-caryophyllene, and naphthalene-derived SOA), (2) SOA II (isoprene-derived SOA), (3) a secondary sulfate factor, and (4) a secondary nitrate factor. In PMF tests without SOA tracers (PMFwo), the SOA I and SOA II factors could not be extracted, but the remaining eight source factors were resolved. Among the eight common source factors, the industrial emission factor, identified by high loadings of Zn and Pb, showed the largest variations between PMFw and PMFwo solutions. The source contributions of SOA I and SOA II resolved in PMFw were largely shifted to the industry emission source in PMFwo. Secondary organic carbon (SOC) summed from the four secondary factors in PMFw contributed ∼40% (4.47 μgC/m3), and the SOC estimate by PMFwo (3.51 μgC/m3) was 21% lower due to the inability to extract SOA I and SOA II. Secondary PM2.5 by PMFwo was 6% lower than that by PMFw (23.7 vs 25.2 μg/m3). The PMFw results indicated that SOC from specific precursors may have different formation pathways than secondary sulfate and nitrate formation processes, and their source contributions could not be properly resolved without the indicative tracers included in PMF. This study demonstrates the utility of biogenic SOA tracers in resolving isoprene-derived SOA and highlights the need for more SOA tracers, especially those specific to anthropogenic precursors, in improving the source apportionment for those broad OA sources such as industrial emissions.