Promising ferrimagnetic double perovskite oxides towards high spin polarization at high temperature

We predict through our first-principles calculations that four double perovskite oxides of Bi2ABO6 (AB = FeMo, MnMo, MnOs, CrOs) are half-metallic ferrimagnets. Our calculated results shows that the four optimized structures have negative formation energy, from -0.42 to -0.26 eV per formula unit, which implies that they could probably be realized. In the case of Bi2FeMoO6, the half-metallic gap and Curie temperature are predicted to reach to 0.71 eV and 650 K, respectively, which indicates that high spin polarization could be kept at high temperatures far beyond room temperature. It is believed that some of them could be synthesized soon and would prove useful for spintronic applications.Comment: 4 pages, 3 figure

Bauerenol inhibits proliferation, migration and invasion of retinoblastoma cells via induction of apoptosis, autophagy and cell cycle arrest

Purpose: To determine the anticancer effects of bauerenol on human retinoblastoma cells. Methods: The effect of bauerenol on cell proliferation was evaluated using 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) assay, while cancer cell migration and invasion were determined by Transwell assay. Apoptosis of retinoblastoma cells was assessed by Annexin VFITC/PI staining procedure. Autophagy was evaluated using TEM, while cell cycle was studied by flow cytometry. Results: Bauerenol significantly inhibited the proliferation of retinoblastoma cells, with a half-maximal inhibitory concentration (IC50) of 10 μM (p < 0.05). However, bauerenol exhibited a comparatively lower antiproliferative effect on normal paediatric retina cells, with a higher IC50 of 100 μM. Annexin V/PI staining results revealed that the antiproliferative effect of bauerenol was due to apoptotic cell death. The proportion of apoptotic SORB-50 cells increased from about 4 % in control to about 19 % on exposure to 20 μM bauerenol. Western blot assay showed marked up-regulation of LC3B II protein, indicating autophagy. Cell cycle analysis showed that the arrest of SO-RB50 cells at the G2/M phase of the cell cycle markedly contributed to the antiproliferative effects of bauerenol. Moreover, the migration and invasion of SO-RB50 cells were suppressed by bauerenol (p < 0.05). Conclusion: These results indicate that bauerenol suppresses the growth of retinoblastoma cells. Therefore, it may be a beneficial lead molecule for the development of a suitable agent for the treatment of retinoblastoma. Keywords: Retinoblastoma; triterpenoid; anticancer; apoptosis; autophagy; migration; invasion; metastasi

Discriminating different scenarios to account for the cosmic e±e^\pm excess by synchrotron and inverse Compton radiation

The excesses of the cosmic positron fraction recently measured by PAMELA and the electron spectra by ATIC, PPB-BETS, Fermi and H.E.S.S. indicate the existence of primary electron and positron sources. The possible explanations include dark matter annihilation, decay, and astrophysical origin, like pulsars. In this work we show that these three scenarios can all explain the experimental results of the cosmic $e^\pm$ excess. However, it may be difficult to discriminate these different scenarios by the local measurements of electrons and positrons. We propose possible discriminations among these scenarios through the synchrotron and inverse Compton radiation of the primary electrons/positrons from the region close to the Galactic center. Taking typical configurations, we find the three scenarios predict quite different spectra and skymaps of the synchrotron and inverse Compton radiation, though there are relatively large uncertainties. The most prominent differences come from the energy band $10^4\sim 10^9$ MHz for synchrotron emission and $\gtrsim 10$ GeV for inverse Compton emission. It might be able to discriminate at least the annihilating dark matter scenario from the other two given the high precision synchrotron and diffuse $\gamma$-ray skymaps in the future.Comment: published in Pr

Synthesis of CdTe quantum dot-conjugated CC49 and their application for in vitro imaging of gastric adenocarcinoma cells

The purpose of this experiment was to investigate the visible imaging of gastric adenocarcinoma cells in vitro by targeting tumor-associated glycoprotein 72 (TAG-72) with near-infrared quantum dots (QDs). QDs with an emission wavelength of about 550 to 780 nm were conjugated to CC49 monoclonal antibodies against TAG-72, resulting in a probe named as CC49-QDs. A gastric adenocarcinoma cell line (MGC80-3) expressing high levels of TAG-72 was cultured for fluorescence imaging, and a gastric epithelial cell line (GES-1) was used for the negative control group. Transmission electron microscopy indicated that the average diameter of CC49-QDs was 0.2 nm higher compared with that of the primary QDs. Also, fluorescence spectrum analysis indicated that the CC49-QDs did not have different optical properties compared to the primary QDs. Immunohistochemical examination and in vitro fluorescence imaging of the tumors showed that the CC49-QDs probe could bind TAG-72 expressed on MGC80-3 cells

Correlation function of flavored fermion in holographic QCD

By using the gauge-gravity duality, we investigate the correlation function of flavored fermion in the $\mathrm{D}_{p}/\mathrm{D}_{p+4}$ model as top-down approaches of holographic QCD for $p=4,3$. The bulk spinor, as the source of the flavored fermion in QCD, is identified to the worldvolume fermion on the flavor $\mathrm{D}_{p+4}$-branes and the standard form of its action can be therefore obtained by the T-duality rules in string theory. Keeping this in hand, we afterwards generalize the prescription for two-point correlation function in AdS/CFT dictionary into general D-brane backgrounds and apply it to the case of $p=4,3$, i.e. the D4/D8 and D3/D7 approach respectively. Resultantly, our numerical calculation with the bubble background always displays discrete peaks in the correlation functions which imply the bound states created by the flavored fermions as the confinement in QCD. With the black brane background, the onshell condition illustrated by the correlation function covers basically the dispersion curves of fermion obtained by the hard thermal loop approximation in the hot medium. In this sense, we conclude remarkably that our top-down approach in this work could reveal the fundamental properties of QCD both in the confined and deconfined phase.Comment: 41 pages; 11 figures; 1 table; fix Figure 7 and Figure 1