• Elastomers and Composites
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• v.42 no.3
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• pp.177-185
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• 2007

Polyamic acid(PAA)/organoclay nanocomposites containing phosphorous were prepared by solution blending of phosphorylated PAA(PPAA) and organically modified montmorillonite(O-MMT) as a type of layered clays. The nanocomposites were characterized by FT-IR, DSC, TGA, PCFC, SEM, and XRD. The preparation of nanocomposites was confirmed by FT-IR and XRD. SEM pictures showed that the organoclay was dispersed well in the PAA matrix relatively. XRD results indicated that the O-MMT layers were intercalated. The thermal stability and flame retardancy of O-MMT/PPAA nanocomposites were higher than those of pure PAA. PCFC results also showed that the heat release capacity and total heat release values of O-MMT 4 wt%/PPAA-0.2, 0.4, 0.6 composites were decreased with increasing the mole ratio of phosphorous. It was found that the nanocomposite films had the potential to be used as a fire safe material.

• Biomedical Science Letters
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• v.29 no.3
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• pp.190-200
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• 2023

Skeletal muscle, essential for metabolism, thermoregulation, and immunity, undergoes myogenic differentiation that results in myotube formation. Trans-anethole (TA), the major constituent in essential oil produced by anise, star anise, and fennel, whose function in skeletal muscle has not yet been elucidated. Therefore, we investigated whether TA influenced muscle differentiation in mouse C2C12 myoblasts. Cells were induced to differentiate using a differentiation medium with or without TA (50 or 200 mg/mL) daily for 5 days. We measured myotube length and diameter after differentiation days 1, 3, and 5 and analyzed the expression of myogenic markers (myoblast determination protein 1, myogenin, myocyte enhancer factor 2, muscle creatine kinase, and myosin heavy chain) and atrophy-related genes (atrogin-1 and muscle ring finger-1 [MuRF-1]) using quantitative real-time PCR. Additionally, we observed the expression of total protein kinase B (Akt) and phosphorylated Akt (p-Akt) using western blotting. Our data showed that TA significantly induced the formation of smaller and thinner myotubes and reduced the myogenic factor expression. Furthermore, the atrogin-1 and MuRF-1 expression markedly increased by TA. Consistent with these findings, TA significantly decreased the expression of total Akt and p-Akt. Taken together, these results indicate that TA inhibits myogenic differentiation of C2C12 cells via reduction of both total Akt and p-Akt. Our findings may provide valuable insights into the impact of PAA on individuals at risk of muscle atrophy.