Receptor protein-tyrosine kinases (RPTKs) are tightly regulated during normal cellular processes including cell growth, differentiation, and metabolism. Recently, a RPTK-like molecule named novel oncogene with kinase-domain (NOK) has been cloned and characterized. Overexpression of NOK caused severe cellular transformation as well as tumorigenesis and metastasis in nude mice. In the current study, we generated two tyrosine!phenylalanine (Y!F) point mutations (Y327F and Y356F) within the endodomain of NOK that are well conserved in many RPTK subfamilies and are the potential tyrosine phosphorylation sites important for major intracellular signaling. Using BaF3 cells stably expressing the ectodomain of mouse erythropoietin receptor, and the transmembrane and endodomain of NOK (BaF3-E/N), we were able to show that point mutations at either Y327 or Y356 dramatically blocked cellular transformation by NOK as examined by colony formation and cellular DNA synthesis. In addition, tumorigenesis induced by BaF3-E/N was completely abrogated upon the introduction of either single mutation. Importantly, signaling studies revealed that the activation of extracellular signal-regulated kinase was inhibited by Y356F and was significantly reduced by Y327F. Both mutations significantly impaired Akt phosphorylation. Interestingly, both mutations did not affect the kinase activity of NOK. Moreover, apoptotic analysis revealed that both mutations accelerated cell death by activating caspase-3-mediated pathways. Thus, our study shows that these potential tyrosine phosphorylation sites may play critical roles in NOKmediated tumorigenesis both in vitro and in vivo. (Cancer Res 2005; 65(23): 10838-46)

Tantalum nitride (TaN) compact with a Vickers hardness of 26 GPa is prepared by a high-pressure and hightemperature (HPHT) method. The crystal structure and atom occupations of WC-type TaN have been investigated by neutron powder diffraction, and the compressibility of WC-type TaN has been investigated by using in-situ high-pressure synchrotron x-ray diffraction. The third-order Birch-Murnaghan equation of state fitted to the x-ray diffraction pressurevolume (P-V ) sets of data, collected up to 41 GPa, yields ambient pressure isothermal bulk moduli of B 0 = 369(2) GPa with pressure derivatives of B 0 = 4 for the WC-type TaN. The bulk modulus of WC-type TaN is not in good agreement with the previous result (B 0 = 351 GPa), which is close to the recent theoretical calculation result (B 0 = 378 GPa). An analysis of the experiment results shows that crystal structure of WC-type TaN can be viewed as alternate stacking of Ta and N layers along the c direction, and the covalent Ta-N bonds between Ta and N layers along the c axis in the crystal structure play an important role in the incompressibility and hardness of WC-type TaN.

One step polyacrylamide gel method was used to synthesize the ZnO/MgO adsorbents and the adsorption behavior with Congo red (CR) from wastewater was extensively investigated. Various advanced techniques were applied to confirm the ZnO/MgO adsorbents consist of Zn, C, Mg and O elements and do not contain any other impurity elements. With the increase of MgO content, the morphology of ZnO/MgO adsorbent changes from the agglomeration of large particles to evenly dispersed fine particles and then to icicle structure. Results demonstrated that the adsorption process of ZnO/MgO adsorbents was significantly affected by the change in initial dye solution pH, initial adsorbent dosage, contact time and reaction temperature. The optimum pH, adsorbent dosage, contact time and reaction temperature is 9.81, 2 g /L, 65 min and 293 K, respectively. The maximum adsorption capacity of ZnO/MgO (nZnO:nMgO = 8:2) adsorbents (295.138 mg/g) for the adsorption of CR dye was approximately double that of previous reports (125 mg/g). The adsorption equilibrium data are well fitted by the Freundlich and Langmuir isotherm models. Thermodynamic studies indicate that the adsorption process of ZnO/MgO adsorbents is an exothermic process. Based on the experimental and theoretical analysis, the adsorption mechanism for the ZnO/MgO adsorbents consisted of hydrogen bonding, n-π interaction and electrostatic interaction. The present work pioneers the potential application of ZnO/MgO adsorbents for the adsorption of CR dye and further provides experimental evidence for the synthesis of other adsorbents.

High pressure pyrolysis of melamine has been attracting great interest recently, due to it being considered as a suitable precursor to realize the g-C3N4 and even superhard C3N4. In this work, we studied the detailed pyrolysis behavior of melamine at 22 GPa. Melamine was stable at 800 °C, and decomposed to diamond in the form of powder at 1500–2000 °C under this pressure condition. At 2000 °C, the pure cubic diamond powders with 0.1–0.5 μm grain size were obtained. The diamond particles exhibited euhedral forms and dispersed to each other, we proposed that these novel features were caused by the presence of liquid N2 and NH3 during diamond formation. The high pressure pyrolysis of melamine may provide a new means of producing micrometer-sized diamond powders.