A deficiency of Ga in the wide bandgap AgGa 1-x Te 2 semiconductor (1.2 eV) can be used to optimize the electrical transport properties and reduce the thermal conductivity to achieve ZT >1 at 873 K. First-principles DFT calculations and a Boson peak observed in the low temperature heat capacity data indicate the presence of strong coupling between optical phonons with low frequency and heat carrying acoustical phonons, resulting in a depressed maximum of Debye frequency in the first Brillouin zone and low phonon velocities. Moreover, the Ag-Te bond lengths and Te-Ag-Te bond angles increase with rising temperature, leading to a significant distortion of the [AgTe 4 ] 7tetrahedra, but an almost unmodified [GaTe 4 ] 5tetrahedra. This behavior results in lattice expansion in the ab plane and contraction along the c axis, corresponding to the positive and negative Gruneisen parameters in the phonon spectral calculations. This effect gives rise to the large anharmonic behavior of the lattice. These factors together with the low frequency vibrations of Ag and Te atoms in the structure lead to an ultralow thermal conductivity of 0.18 Wm -1 K -1 at 873 K.

We investigated the continuous extrusion foaming of poly­(vinyl alcohol) (PVOH)/microfibrillated cellulose (MFC) composites using supercritical carbon dioxide (scCO2) as the blowing agent. First, the as-received PVOH pellets were compounded with water to decrease their melting point. Then, they were compounded with an MFC solution to prepare the sample. Both scanning electron microscopy (SEM) and environmental scanning electron microscopy (ESEM) showed that the MFC dispersed well in the PVOH/MFC composites. Differential scanning calorimetry (DSC) results showed that adding MFC affected the thermal behavior. This, in turn, affected cell nucleation and cell growth phenomena during foam extrusion. Water also acted as a co-blowing agent, together with scCO2, in creating biodegradable polymer foams with a uniform cell structure and a high cell density. The effects of the MFC content, scCO2 content, and die temperature variations on the cell density and cellular morphology of the PVOH/MFC composite foams were examined systematically.

A series of cyclopalladated arylimine self‐assembly films were prepared through chemical grafting to substrates and used to catalyze a Suzuki coupling reaction. Atomic force microscopy, water contact angle analysis, cyclic voltammetry, scanning electron microscopy, attenuated total‐reflectance infrared, and X‐ray photoelectron spectroscopy were used to analyze the morphology and composition of the heterogeneous catalysts. The results show that these cyclopalladated arylimine self‐assembly films immobilized on substrates could be used as efficient and reusable heterogeneous catalysts in the Suzuki reaction of aryl bromides under open air conditions in aqueous solution. These catalysts exhibited 10 times the catalytic performance of the homogeneous counterpart. The palladium catalysts were grafted onto the internal surface of the round‐bottomed flasks. The reaction flasks acted as both reaction vessels and catalysts, which simplified the reaction operations. The catalysts were run over 8 cycles without showing any sign of deactivation, suggesting the potential of the catalysts as advanced functional materials with applications in the heterogeneous catalysis of Suzuki reactions.

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The foaming behavior and thermal properties of neat polylactide (PLA) and PLA/cotton-fiber composite foams were investigated in this study. CO2 saturation pressure, temperature, and fibers content significantly affected PLA’s crystallinity and foaming behaviors. At the same saturation temperature (140 °C), a low CO2 pressure generated nonuniform foam and a large unfoamed area due to too high crystallinity with a close-packed structure. At an intermediate pressure, a fine-cell structure was developed due to the presence of numerous less closely packed crystals served as cell nucleating agents. A high CO2 pressure also led to a uniform cell structure but with larger cell sizes due to cell deterioration. Similar to the effect of saturation pressure, an intermediate temperature generated the uniform fine-cell structures. The PLA’s cell morphology was improved by the addition of cotton fibers at a low content because of the increased local stresses through the fibers and transcrystals surrounding the fibers.

Previous study has found that a new nitroxyl spin-labeled derivative of podophyllotoxin, 4-[4"-(2",2",6",6"-tetramethyl-1"-piperidinyloxy)amino]-4'-demethyl-epipodophyllotoxin (GP7), can induce apoptosis in human leukemia cells. However, there have been no studies about the effects of GP7 on osteosarcoma (OS) cells. Here, we observed the anti-OS effects of GP7 in mouse and human OS cells with the comparison of etoposide. GP7 and etoposide inhibited the proliferation of a panel of mouse and human OS cells in a concentration- or time-dependent manner, and the inhibitory effect of GP7 on the proliferation of mouse LM8 or human U2OS cells was 1.28- or 1.35-fold higher than that of etoposide. GP7 or etoposide augmented the anti-OS effects of methotrexate, adriamycin, cisplatin, or their combination, and the combined inhibitory effects of GP7 with MTX on the proliferation of LM8 cells was higher than those of etoposide with MTX. GP7 arrested the cell cycle in S phase but etoposide in G(2)/M phase. GP7 or etoposide induced sub-G(1) peak, apoptotic DNA fragmentation, activations of caspase-3, -8, -9, and DNA fragmentation factor, downregulation of Bcl-2 and Bcl-xL, upregulation of Bax and Bak, and cytochrome-c release from mitochondria in both mouse and human OS cells. GP7 or etoposide also induced endonuclease G translocation from mitochondria into cytosol in mouse cells. GP7- or etoposide-induced apoptotic DNA fragmentation of human OS cells was inhibited by the pan caspase inhibitor and caspase-9 inhibitor, not by caspase-8 inhibitor whereas it was not inhibited by the pan caspase inhibitor in mouse OS cells. Our findings indicate that GP7 is effective against mouse and human OS cells in vitro. The apoptotic DNA fragmentation in mouse OS cells may be mediated by caspase-independent pathway with the involvement of endonuclease G whereas in human OS cells by caspase-9-dependent pathway downstream of the cytochrome-c-initiated caspase cascade.