We herein report on the preparation of epoxy nanocomposites, which had enhanced thermal conductivities but were still electrical insulators, incorporating hybrid nanosheets (NSs) with sandwich structures composed of thermally reduced graphene oxide (TRGO) and silica. The silica layer covered the surface of the TRGO, hindering electrical conduction and effectively forming a 3D phonon transport channel that had a unique effect on the electrical and thermal properties of the epoxy matrix. A 1 wt% TRGO-silica NS epoxy nanocomposite maintained an electrical resistivity of 2.96 × 10(11)Ω cm, and its thermal conductivity was 0.322 W m(-1) K(-1), which is 61% higher than the conductivity of an epoxy nanocomposite without TRGO-silica NSs (0.2 W m(-1) K(-1)).

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Tagitinin C, a major sesquiterpenoid, was isolated from the leaves of Tithonia diversifolia. The high morbidity and mortality rate of hepatoma in Taiwan motivated our interest in the investigation of tagitinin C's mechanism against the human hepatocellular carcinoma. The methanolic extract of leaves of T. diversifolia (TDM) and tagitinin C were found to have cytotoxic activities against human hepatoma Hep-G2 cells in the MTT assay with IC(50) values of 40.0 ± 2.0 and 2.0 ± 0.1 μg/mL, respectively. This compound induced population increase in the sub-G(1) phase and S phase arrest. Treatment with tagitinin C isolated from TDM resulted in activation of both caspase 3 and caspase 8 which suggested that the antiproliferative effect of this compound was caspase-dependent apoptosis. Magnetic resonance techniques indicated that the tumorigenisity of xenografts derived from Hep-G2 cells was retarded by the delivery of tagitinin C (15 μg/mouse/day) relative to the control counterparts.

The ribosomal protein Rpl12p of Saccharomyces cerevisiae is encoded by duplicated genes, RPL12A and RPL12B. The gene products possess an identical amino acid sequence. Yeast strain 6EA1, which lacks both genes, is viable but exhibits a very slow-growth phenotype. In this study, 6EA1 cells were transformed with plasmids carrying either RPL12A or RPL12B, and the transcriptional profiles of wild-type W303, 6EA1 and the transformed cells grown in synthetic complete medium were examined by microarray analysis. Transcription of PHO84, a gene encoding a high-affinity phosphate transporter, was drastically suppressed in 6EA1. PHO84 expression is induced under phosphate-limiting conditions. Therefore, cells were grown in low-phosphate medium and transcripts encoding the PHO pathway proteins were quantified by qRT-PCR. The high-affinity phosphate transporters and repressible phosphatases were suppressed, while PHO4, a PHO pathway transcription activator, was upregulated in 6EA1. Accordingly, phosphate transport and acidic phosphatase activities were significantly decreased in 6EA1. Addition of RPL12A or RPL12B to 6EA1 largely lessens these effects. We postulate that RPL12 has an extra-ribosomal function in modulating the transcription of genes that need Pho4p activation.

We describe the preparation of vinyl-terminated benzoxazine-functionalized graphene using free radical grafting. The resulting functionalized graphene (f-graphene) was incorporated into bis(3-allyl-3,4-dihydro-2H-1,3-benzoxazinyl)methane (V-BF-a) monomer in order that nanocomposites could be prepared. Results of scanning electron microscopy and transmission electron microscopy revealed that the sheets of f-graphene were well dispersed throughout the matrix, and there was a strong interfacial interaction between the f-graphene and polyV-BF-a. The inclusion of f-graphene into the nanocomposites resulted in a material with a high thermal stability and a low coefficient of thermal expansion (CTE); increasing the content of f-graphene reduced the CTE significantly more. A reduction in the CTE of up to 48% was produced by adding just 1 wt% of f-graphene; this corresponded to an increase of 12 • C in the glass transition temperature. These results suggest that f-graphene nanocomposites can be 'tuned' to give materials with both a low CTE and a high thermal stability, and that graphene composites of this type can thus be manufactured to withstand a wider range of temperatures.