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Optimizing n-type PbTe thermoelectric materials to match their better-performing p-type counterparts is critical for realizing their practical applications. To overcome this gap, dynamic doping, due to its temperature-dependent self-optimizing carrier concentration, has recently arisen as an effective method to improve the performance of n-type PbTe. However, their evitable dynamic compositional evolution must lead to structure evolution at elevated temperatures, which may have a negative effect on suppressing phonon transport, verified by the observed high lattice thermal conductivity (κlat) of Ag-doped n-type PbTe. Herein, we describe the significance of Mn alloying in enhancing the performance of Ag-doped n-type PbTe by creating a hierarchical structure to suppress thermal transport and improving the Seebeck coefficient by flattening the L point of the conduction band. Systematic characterization analysis reveals that the constructed hierarchical structure primarily consists of Ag2Te-decorated grain boundaries, dispersive MnTe nanoprecipitates, and atomic disorders induced by multi-doping in the matrix, which significantly suppressed κlat across the entire temperature range. In consequence, a high ZT ∼1.4 of Ag0.03Pb0.95Mn0.05Te at 773 K and an average ZT ∼0.8 of Ag0.03Pb0.99Mn0.01Te in the range of 323–823 K were obtained, which were ascribed to the weakening of the coupling between electron and phonon transport. This work demonstrates an upgraded approach to enhance the thermoelectric performance of dynamically-doped PbTe materials through unique structural design, which can be applied to other thermoelectric material systems with high performance. [ABSTRACT FROM AUTHOR]

In order to investigate the potential of nanostructured lipid carriers for efficient and targeted delivery of curcumin, the pharmacokinetic parameters of curcumin-loaded nanostructured lipid carriers (Cur-NLC) were evaluated in rats after a single intraperitoneal dose of Cur-NLC. In addition, the anticancer activity of Cur-NLC against human lung adenocarcinoma A549 cells was verified by a cellular uptake study, and a cytotoxicity and apoptosis assay. Bioavailability of Cur-NLC was better than that of native curcumin (p > 0.01), as seen from the area under the plasma concentration-time curve (AUC), maximum plasma concentration (Cmax), mean residence time (MRT) and total plasma clearance (CLz/F). Cur-NLC has a more obvious lung-targeting property in comparison with native curcumin. Cur-NLC showed higher anticancer activity in vitro against A549 cells than native curcumin (IC50 value of 5.66 vs. 9.81 mg L−1, respectively). Meanwhile, Cur-NLC treated A549 cells showed a higher apoptosis rate compared to that of native curcumin. These results indicate that NLC is a promising system for the delivery of curcumin in the treatment of lung adenocarcinoma.

Background: Curcumin (diferuloylmethane), the active constituent of turmeric extract has potent anti-cancer properties have been demonstrated in hepatocellular carcinoma (HCC). However, its underlying molecular mechanism of therapeutic effects remains unclear. Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) have crucial roles in tumor angiogenesis.Purpose: The goal of this study was to investigate the role of the VEGF/VEGFRs mediated angiogenesis during the proliferation and apoptosis of human HepG2 hepatoma cell line and the effect of curcumin-loaded nanostructured lipid carriers (Cur-NLC).Materials and Methods: The proliferation of HepG2 cells was determined by methyl thiazolyl tetrazolium after exposure to Cur-NLC and native curcumin. Apoptosis was quantified by flow cytometry with annexin V-fluorescein isothiocyanate and propidium iodide staining. Cellular internalization of Cur-NLC was observed by fluorescent microscope. The level of VEGF was detected by enzyme-linked immunosorbent assay kits. The expression of VEGFRs was quantified by Western blotting.Results: Cur-NLC was more effective in inhibiting the proliferation and enhancing the apoptosis of HepG2 cells than native curcumin. Fluorescent microscope analysis showed that HepG2 cells internalized Cur-NLC more effectively than native curcumin. Furthermore, Cur-NLC down-regulated the level of VEGF and the expression of VEGFR-2, but had a slight effect on VEGFR-1.Conclusion: These results clearly demonstrated that Cur-NLC was more effective in anti-cancer activity than the free form of curcumin. These studies demonstrate for the 1 st time that Cur-NLC exerts an antitumor effect on HepG2 cells by modulating VEGF/VEGFRs signaling pathway. [ABSTRACT FROM AUTHOR]