Effects of ammonia on morphological characteristics and nanostructure of soot in the combustion of diesel surrogate fuels.

The morphological characteristics and nanostructure of soot particles in pure n-heptane (C7H16) and n-heptane/ammonia co-flow diffusion flames were analyzed and compared using thermophoretic sampling and transmission electron microscopy (TEM) observation combining with quantitative image information extraction methods. The results showed that the overall formation and evolution of soot particles in NH3-doped n-heptane flames along the flame centerline were similar with that without NH3-doping. However, compared to n-heptane flame, the peak average diameter of primary soot particles and the peak gyration radius of soot aggregates in NH3-doped flames were reduced by about 45% and 37%, respectively, which indicated that the growth of both primary soot particles via surface reaction/condensation and soot aggregates via coagulation were significantly decreased. Meanwhile, the fractal dimension of soot aggregates was lower with NH3 addition as the structure of soot aggregates was looser and tended to be more chain-like. After NH3 doping, the peak average fringe length inside soot particles was decreased by 13%, and the inter-fringe spacing and tortuosity of soot were increased by 8% and 3%, respectively. This represented a more disordered microcrystal structure and lower degree of graphitization of soot particles, meaningfully indicating a higher oxidation reactivity.

Natural products: potential therapeutic agents for atherosclerosis.

Atherosclerosis (AS) is an invisible killer among cardiovascular diseases (CVD), which has seriously threatened the life of quality. The complex pathogenesis of AS involves multiple interrelated events and cell types, such as macrophages, endothelial cells, vascular smooth muscle cells and immune cells. Currently, the efficacy of recommended statin treatment is not satisfactory. Natural products (NPs) have attracted increasing attention with regard to their broad structural diversity and biodiversity, which makes them a promising library in the demand for lead compounds with cardiovascular protective bio-activity. NPs can preclude the development of AS by regulating lipid metabolism, ameliorating inflammation, stabilizing plaques, and remodeling the gut microbiota, which lays a foundation for the application of NPs in clinical therapeutics.

Enhanced tumor homing of pathogen-mimicking liposomes driven by R848 stimulation: A new platform for synergistic oncology therapy.

Although multifarious tumor-targeting modifications of nanoparticulate systems have been attempted in joint efforts by our predecessors, it remains challenging for nanomedicine to traverse physiological barriers involving blood vessels, tissues, and cell barriers to thereafter demonstrate excellent antitumor effects. To further overcome these inherent obstacles, we designed and prepared mycoplasma membrane (MM)-fused liposomes (LPs) with the goal of employing circulating neutrophils with the advantage of inflammatory cytokine-guided autonomous tumor localization to transport nanoparticles. We also utilized in vivo neutrophil activation induced by the liposomal form of the immune activator resiquimod (LPs-R848). Fused LPs preparations retained mycoplasma pathogen characteristics and achieved rapid recognition and endocytosis by activated neutrophils stimulated by LPs-R848. The enhanced neutrophil infiltration in homing of the inflammatory tumor microenvironment allowed more nanoparticles to be delivered into solid tumors. Facilitated by the formation of neutrophil extracellular traps (NETs), podophyllotoxin (POD)-loaded MM-fused LPs (MM-LPs-POD) were concomitantly released from neutrophils and subsequently engulfed by tumor cells during inflammation. MM-LPs-POD displayed superior suppression efficacy of tumor growth and lung metastasis in a 4T1 breast tumor model. Overall, such a strategy of pathogen-mimicking nanoparticles hijacking neutrophils in situ combined with enhanced neutrophil infiltration indeed elevates the potential of chemotherapeutics for tumor targeting therapy.

Seven new guanacastane-type diterpenoids from the fungus Verticillium dahliae.

Seven new guanacastane-type diterpenoids, namely dahlianes E-K (1-7), and three known ones (8-10) were isolated from the cultures of the fungus Verticillium dahliae. Their structures were established by extensive spectroscopic data analysis along with Rh2(OCOCF3)4- and Mo2(OAc)4-induced electronic circular dichroism (ECD) experiment. Dahliane G showed an 80-fold potentiation effect on the sensitization of doxorubicin at the concentration of 15 µM when screening the reversal activity on doxorubicin-resistant human breast cancer cells (MCF-7/DOX).

Seven new cytotoxic phenylspirodrimane derivatives from the endophytic fungus Stachybotrys chartarum.

Seven undescribed phenylspirodrimane derivatives, stachybochartins A-G (1-7), and four known analogues (8-11) were isolated from the endophytic fungus Stachybotrys chartarum obtained from Pinellia ternata. Stachybochartins A-D are four rare C-C-coupled dimeric derivatives and stachybochartin G features a seco-bisabosqual skeleton. Their structures and configurations were elucidated via spectroscopic analysis, electronic circular dichroism (ECD) calculations, the ECD exciton chirality method and the modified Mosher's method. Stachybochartins A-D and G displayed cytotoxic activities against MDA-MB-231 breast cancer cells and U-2OS osteosarcoma cells, with IC50 values ranging from 4.5 to 21.7 µM. Stachybochartins C and G exerted strong anti-proliferative activities against U-2OS cells in concentration- and time-dependent manners and induced apoptosis.