ALBERT

Description: The magnetic structure and magnetic transport properties of hydrogen-passivated sawtooth zigzag-edge graphene nanoribbons (STGNRs) are investigated theoretically. It is found that all-sized ground-state STGNRs are ferromagnetic and always feature magnetic semiconductor properties, whose spin splitting energy gap Eg changes periodically with the width of STGNRs. More importantly, for the STGNR based device, the dual spin-filtering effect with the perfect (100%) spin polarization and high-performance dual spin diode effect with a rectification ratio about 1010 can be predicted. Particularly, a highly effective spin-valve device is likely to be realized, which displays a giant magnetoresistace (MR) approaching 1010%, which is three orders magnitude higher than the value predicted based on the zigzag graphene nanoribbons and six orders magnitude higher than previously reported experimental values for the MgO tunnel junction. Our findings suggest that STGNRs might hold a significant promise for developing spintronic devices. Scientific Reports 4 doi: 10.1038/srep07587

Description: Central Asia is currently a semiarid-arid region, dominated by the Westerlies. It is important to understand mechanisms of climate and precipitation changes here, as water availability in the region is crucial today and in the future. High-resolution, absolutely-dated oxygen isotope (δ18O) records of stalagmites from Kesang Cave characterize a dynamic precipitation history over most of the past 500,000 years. This record demonstrates, for the first time, that climate change in the region exhibits a processional rhythm with abrupt inceptions of low δ18O speleothem growth at times of high Northern Hemisphere summer insolation followed by gradual δ18O increases that track decreases of insolation. These observations and interpretations contrast with the interpretation of nearby, but higher elevation ice core records. The absolutely-dated cave δ18O shifts can be used to correlate the regional climate variability by providing chronological marks. Combined with other paleoclimate records, the Kesang observations suggest that possible incursions of Asian summer monsoon rainfall or related moisture into the Kesang site and/or adjacent areas during the high insolation times may play an important role in changing orbital-scale hydrology of the region. Based on our record, arid climate will prevail in this region for the next several millennia, providing that anthropogenic effects do not supersede natural processes.

Description: Wentilactone B induces G2/M phase arrest and apoptosis via the Ras/Raf/MAPK signaling pathway in human hepatoma SMMC-7721 cells Cell Death and Disease 4, e657 (June 2013). doi:10.1038/cddis.2013.182 Authors: Z Zhang, L Miao, C Lv, H Sun, S Wei, B Wang, C Huang & B Jiao

Description: A continuous countercurrent supercritical CO 2 extraction-distillation dual-column process was developed to extract and concentrate natural vitamin E (VE) from soybean oil deodorizer distillate (SODD). The experimental results demonstrated that process parameters such as extraction pressure, temperature, and solvent-to-feed ratio significantly impacted on the extraction efficiency of natural VE. A new five-parameter mass transfer model for the continuous countercurrent supercritical CO 2 extraction-distillation dual-column process was presented based on the Penetration and Double-Film theories. The calculated values of the mathematical model agreed well with the experimental data, with absolute average relative deviation values of less than 25 %. A continuous countercurrent supercritical CO 2 extraction-distillation dual-column process was developed to extract and concentrate natural vitamin E from soybean oil deodorizer distillate. A new five-parameter mass transfer model for this process was presented based on the Penetration and Double-Film theories.

Description: Soot oxidation with NO (in the absence of gas phase O 2 ) on potassium-supported Mg-Al hydrotalcite mixed oxides (K/MgAlO) was studied using a temperature-programmed reaction and in situ FTIR techniques. Nitrite and the ketene group were identified as the reaction intermediates and thus a nitrite-ketene mechanism was proposed in which surface active oxygen on K sites of K/MgAlO is transferred to soot by NO through nitrites. In the absence of gas phase O 2 , soot oxidation with NO at lower temperatures (below 450 °C) is limited by the amount of active oxygen on the K sites. This kind of active oxygen is not reusable but can be replenished in the presence of gas phase O 2 . Soot oxidation with NO on K/MgAIO was studied by temperature-programmed reaction and in situ FTIR. The nitrite and the ketene group were identified as the reaction intermediates and thus a nitrite–ketene mechanism was proposed, in which surface active oxygen on K sites is transferred to soot by NO through nitrites, forming the ketene group.

Description: The antitumor natural compound falcarindiol promotes cancer cell death by inducing endoplasmic reticulum stress Cell Death and Disease 3, e376 (August 2012). doi:10.1038/cddis.2012.122 Authors: H R Jin, J Zhao, Z Zhang, Y Liao, C-Z Wang, W-H Huang, S-P Li, T-C He, C-S Yuan & W Du

Description: We present the results of three-dimensional, nonhydrostatic simulations of internal tides and waves in the South China Sea (SCS) using the SUNTANS model. Model results accurately predict the observed wave arrival times at two mooring locations in the SCS. Internal wave amplitudes are underpredicted which causes underprediction of internal wave speeds due to a lack of amplitude dispersion. We show that the well-known A and B waves arise from the steepening of semidiurnal internal tides that are generated due to strong barotropic flow over ridges in the Luzon Strait. A wave generation is stronger in the southern portion of the Luzon Strait because diurnal internal tidal beams augment the amplitude of the semidiurnal A waves. B wave generation is stronger in the northern portion where the distance between the eastern and western ridges is approximately equal to one internal tidal wavelength and leads to semidiurnal internal tidal resonance. The orientation of the ridges produces large A waves that propagate into the northern portion of the western SCS basin and stronger B waves that propagate into the southern portion. When traced back in time along linear characteristics, A waves consistently line up close to peak ebb (eastward) barotropic currents, while B waves consistently line up with peak flood (westward) barotropic currents. This reinforces the notion that the lee wave mechanism and associated hydraulic or nonlinear effects are weak, as demonstrated by a simple linear model relating the amplitude of the simulated waves to the excursion parameter at the ridges.

Description: Surface ozone (O3), carbon monoxide (CO), and total and speciated reactive nitrogen compounds (NOy, NO, NO2, PAN, HNO3, and particulate NO3−) were measured at Mount Waliguan (WLG; 36.28°N, 100.90°E, 3816 m above sea level (asl)) in the summer of 2006 to further understand the sources of ozone and reactive nitrogen and to investigate the partitioning of reactive nitrogen over the remote Qinghai-Tibetan Plateau. The mean mixing ratios of O3, CO, NOy, and daytime NO were 59 ppbv, 149 ppbv, 1.44 ppbv, and 71 pptv, respectively, which (except for NOy) were higher than those measured from a previous campaign in summer 2003, which is consistent with more frequent transport of anthropogenic pollution from central and eastern China in the measurement period of 2006 (55%) than that of 2003 (25%). The abnormally high values of NOy observed in 2003 were suspected to be due to the positive interference from ammonia (NH3) to the particular catalytic converter used in that study. Varied diurnal patterns were observed for the various NOy components. The ozone production efficiencies (ΔO3/ΔNOz), which were estimated from the slope of the O3-NOz scatterplot, were 7.7–11.3 for the polluted plumes from central and eastern China. The speciation of reactive nitrogen was investigated for the first time in the remote free troposphere in western China. PAN and particulate NO3− were the most abundant reactive nitrogen species at WLG, with average proportions of 32% and 31%, followed by NOx (24%) and HNO3 (20%). The relatively large contribution of particulate NO3− to NOy was due to the presence of high concentrations of NH3 and crustal particles, which favor the formation of particulate nitrate. An analysis of backward trajectories for the recent 10 years revealed that air masses from central and eastern China dominated the airflow at WLG in summer, suggesting strong impact of anthropogenic forcing on the surface ozone and other trace constituents on the Plateau.

Description: Long-term cultured mesenchymal stem cells frequently develop genomic mutations but do not undergo malignant transformation Cell Death and Disease 4, e950 (December 2013). doi:10.1038/cddis.2013.480 Authors: Y Wang, Z Zhang, Y Chi, Q Zhang, F Xu, Z Yang, L Meng, S Yang, S Yan, A Mao, J Zhang, Y Yang, S Wang, J Cui, L Liang, Y Ji, Z-B Han, X Fang & Z C Han

Description: IBP-mediated suppression of autophagy promotes growth and metastasis of breast cancer cells via activating mTORC2/Akt/FOXO3a signaling pathway Cell Death and Disease 4, e842 (October 2013). doi:10.1038/cddis.2013.380 Authors: S Chen, Q Han, X Wang, M Yang, Z Zhang, P Li, A Chen, C Hu & S Li