Our findings indicate that even if the prevalence of colorectal adenoma was low in young adults aged 20 to 39, being over 30, cigarette smoking, and alcohol consumption can affect young adults who have no other CRC risks.

2Graphical abstract Highlights 1. Co-Ni mixed oxide having the ratios of Co to Ni of (50:50) exhibits the highest activity among the known transition metal oxide catalysts.2. Co-Ni mixed oxides having the ratios of Co to Ni of (50:50) show the highest activity for methane combustion.3. Distorted NiCo2O4 spinel structure plays a key role as the active sites for methane combustion.3 Abstract A series of cobalt nickel mixed oxide catalysts with the varying ratios of Co to Ni, prepared by co-precipitation method, were applied to methane combustion. Among the various ratios, cobalt nickel mixed oxides having the ratios of Co to Ni of (50:50) and (67:33) demonstrate the highest activity for methane combustion. Structural analysis obtained from X-Ray Diffraction (XRD) and Extended X-ray Absorption Fine Structure (EXAFS) evidently demonstrates that CoNi (50:50) and (67:33) samples consist of NiCo2O4 and NiO phase and, more importantly, NiCo2O4 spinel structure is largely distorted, which is attributed to the insertion of Ni 2+ ions into octahedral sites in Co3O4 spinel structure. Such structural disorder results in the enhanced portion of surface oxygen species, thus leading to the improved reducibility of the catalysts in the low temperature region as evidenced by temperature programmed reduction by hydrogen (H2 TPR) and X-ray Photoelectron Spectroscopy (XPS) O 1s results. They prove that structural disorder in cobalt nickel mixed oxides enhances the catalytic performance for methane combustion. Thus, it is concluded that a strong relationship between structural property and activity in cobalt nickel mixed oxide for methane combustion exists and, more importantly, distorted NiCo2O4 spinel structure is found to be an active site for methane combustion.

Using infrared transmission and Raman spectroscopy, we have studied the optical phonon modes of GaN layers grown on GaAs(001) substrates by molecular beam epitaxy. The crystal structure of the GaN layers ranges from predominantly wurtzite to predominantly zincblende depending on the growth conditions. The transverse and longitudinal optical phonons in cubic GaN are found to be at 552 and 739 cm−1, respectively. These frequencies are slightly shifted with respect to the corresponding A1 and E1 phonon modes in hexagonal GaN. The frequency shifts, together with Raman scattering selection rules, can be used for identifying the phase composition of GaN. A more distinct fingerprint of the hexagonal phase is provided by the occurrence of the E2 phonon modes that are spectrally separated from optical phonon modes in the cubic phase and thus uniquely related to the hexagonal phase.

The reaction kinetics over a V2O5−WO3/TiO2 catalyst which can describe the NH3 slip from a selective catalytic reduction (SCR) reactor as well as the maximum conversion of NO over a wide range of reaction temperatures was developed to design the SCR process. The modeling of the reactor based upon the kinetics developed in the present study was successfully accomplished by the inclusion of the effect of diffusion resistance in the honeycomb reactor model. The honeycomb reactor model could directly employ the kinetic parameters obtained from the kinetic study over a packed-bed flow reactor. The model could also predict the effects of the catalytic wall thickness on the honeycomb reactor and the pore structure of the catalyst on the NO removal activity and NH3 slip, regardless of the types of the honeycomb, washcoated or extruded. The present study also identified that the diffusion resistance in the honeycomb reactor plays a critical role in the design of the commercial-scale SCR reactor despite the relatively thin catalyst layer of the reactor. Moreover, the diffusion effect was more significant for a CuHM catalyst primarily containing micropores than for a V2O5−WO3/TiO2 catalyst primarily containing mesopores. The flow pattern and the NH3 distribution in the commercial-scale honeycomb reactor are also important for a high performance of NO removal. Good distribution of the flow by the guide vanes installed in the reactor can improve the NO removal activity by more than 10% of NO conversion.

In situ high-pressure angle dispersive x-ray diffraction experiments using synchrotron radiation on inverse spinel structure Zn2SnO4 nanowires were carried out with a diamond anvil cell at room temperature. The crystal symmetry becomes lower at around 12.9 GPa and an intermediate phase with an orthorhombic structure occurs. At about 32.7 GPa, a phase transition occurs accompanying a high-pressure phase. In situ Raman scattering investigation was also performed to explore the phase transition. In the pressure range 15.5–32.8 GPa, the intermediate phase is also detected and a high-pressure phase is observed above 32.8 GPa. The high-pressure phase is considered to possess the ambient pressure structure of CaFe2O4.