Enhancement of the superconducting gap by nesting in CaKFe4As4 - a new high temperature superconductor

We use high resolution angle resolved photoemission spectroscopy and density functional theory with experimentally obtained crystal structure parameters to study the electronic properties of CaKFe4As4. In contrast to related CaFe2As2 compounds, CaKFe4As4 has high Tc of 35K at stochiometric composition. This presents unique opportunity to study properties of high temperature superconductivity of iron arsenic superconductors in absence of doping or substitution. The Fermi surface consists of three hole pockets at $\Gamma$ and two electron pockets at the $M$ point. We find that the values of the superconducting gap are nearly isotropic, but significantly different for each of the FS sheets. Most importantly we find that the overall momentum dependence of the gap magnitudes plotted across the entire Brillouin zone displays a strong deviation from the simple cos(kx)cos(ky) functional form of the gap function, proposed in the scenario of the Cooper-pairing driven by a short range antiferromagnetic exchange interaction. Instead, the maximum value of the gap is observed for FS sheets that are closest to the ideal nesting condition in contrast to the previous observations in some other ferropnictides. These results provide strong support for the multiband character of superconductivity in CaKFe4As4, in which Cooper pairing forms on the electron and the hole bands interacting via dominant interband repulsive interaction, enhanced by FS nesting}.Comment: 5 pages, 4 figure

The role of macroeconomic policy in export-led growth

노트 : - This PDF is a selection from an out-of-print volume from the National Bureau of Economic Research -Volume Title: Financial Deregulation and Integration in East Asia, NBER-EASE Volume

Stilbenes Inhibit Androgen Receptor Expression in 22Rv1 Castrate-resistant Prostate Cancer Cells

Androgen receptor (AR) signaling plays an important role in the development and progression of prostate cancer (PCa). Importantly, AR continues to be expressed in advanced castrate-resistant PCa (CRPC), where the AR can have ligand-independent activity. Identification of naturally occurring substances that can inhibit AR expression holds promise for PCa chemoprevention and therapy. Earlier research demonstrated that resveratrol (Res) inhibited androgenpromoted growth, AR expression, and transactivation in androgen-responsive non-metastatic LNCaP PCa cells. In the current study, the effects of Res and three natural analogs [trimethoxyresveratrol (3M-Res), pterostilbene (Pter), and piceatannol (Pic)] were investigated for effects on the growth of 22Rv1 castrate-resistant cells that express full-length (AR114/110) and truncated form (AR80) of AR. Although all the stilbenes tested inhibited the proliferation of 22Rv1 cells in a dose-dependent manner, 3M-Res was the most potent inhibitor. While AR114/110 responded to the syn-thetic androgen agonist methyltrienolone (R1881) as well as to antiandrogen flutamide, AR80, which lacks a ligand-binding domain, did not respond to R1881, but was inhibited by flutamide. Interestingly, Res, Pter, and Pic, but not 3M-Res, similar to flutamide, inhibited both AR114/110 and AR80 with the effect on AR80 being more prominent with the use of high concentrations of stilbenes. Collectively, the data indicate that both AR-independent (3M-Res) and possibly AR-dependent (Res, Pter, and Pic) mechanisms of cell growth inhibition occurs via these stilbenes. These findings provide evidence for plant-derived stilbenes as attractive and promising pharmacologically safe compounds to be used for diminishing progression and curb worsening of CRPC

Geographical, meteorological and vectorial factors related to malaria re-emergence in Huang-Huai River of central China

<p/> <p>Background</p> <p>Malaria still represents a significant public health problem in China, and the cases dramatically increased in the areas along the Huang-Huai River of central China after 2001. Considering spatial aggregation of malaria cases and specific vectors, the geographical, meteorological and vectorial factors were analysed to determine the key factors related to malaria re-emergence in these particular areas.</p> <p>Methods</p> <p>The geographic information of 357 malaria cases and 603 water bodies in 113 villages were collected to analyse the relationship between the residence of malaria cases and water body. Spearman rank correlation, multiple regression, curve fitting and trend analysis were used to explain the relationship between the meteorological factors and malaria incidence. Entomological investigation was conducted in two sites to get the vectorial capacity and the basic reproductive rate to determine whether the effect of vector lead to malaria re-emergence.</p> <p>Results</p> <p>The distances from household of cases to the nearest water-body was positive-skew distributed, the median was 60.9 m and 74% malaria cases were inhabited in the extent of 60 m near the water body, and the risk rate of people live there attacked by malaria was higher than others(<it>OR </it>= 1.6, 95%<it>CI </it>(1.042, 2.463), <it>P </it>< 0.05). The annual average temperature and rainfall may have close relationship with annual incidence. The average monthly temperature and rainfall were the key factors, and the correlation coefficients are 0.501 and 0.304(<it>P </it>< 0.01), respectively. Moreover, 75.3% changes of monthly malaria incidence contributed to the average monthly temperature (T_mean), the average temperature of last two months(T_mean01) and the average rainfall of current month (R_mean) and the regression equation was Y = -2.085 + 0.839I₁+ 0.998T_mean0- 0.86T_mean01+ 0.16R_mean0. All the collected mosquitoes were <it>Anopheles sinensis</it>. The vectorial capacity and the basic reproductive rate of <it>An. sinensis </it>in two sites were 0.6969, 0.4983 and 2.1604, 1.5447, respectively.</p> <p>Conclusion</p> <p>The spatial distribution between malaria cases and water-body, the changing of meteorological factors, and increasing vectorial capacity and basic reproductive rate of <it>An. sinensis </it>leaded to malaria re-emergence in these areas.</p

Alpha-lipoic acid induces apoptosis in hepatoma cells via the PTEN/Akt pathway

AbstractWe report here that alpha-lipoic acid (α-LA), a naturally-occurring antioxidant, scavenges reactive oxygen species (ROS) followed by an increase in apoptosis of human hepatoma cells. Apoptosis induced by α-LA was dependent upon the activation of the caspase cascade and the mitochondrial death pathway. α-LA induced increases in caspase-9 and caspase-3 but had no significant effect on caspase-8 activity. Apoptosis induced by α-LA was found to be mediated through the tensin homologue deleted on chromosome 10 (PTEN)/Akt pathway. Prior to cell apoptosis, PTEN was activated and its downstream target Akt was inhibited. Our findings indicate that increasing ROS scavenging could be a therapeutic strategy to treat cancer

The role of cellular oxidative stress in regulating glycolysis energy metabolism in hepatoma cells

<p>Abstract</p> <p>Background</p> <p>The Warburg effect has been found in a wide spectrum of human cancers, however the underlying mechanisms are still unclear. This study aims to explore the role of cellular oxidative stress in relation to glycolysis and the Warburg effect in hepatoma cells.</p> <p>Methods</p> <p>Various cell lines combining environmental hypoxia was used as an in vitro model to mimic tumor microenvironment in vivo. Superoxide dismutases (SOD) and xanthine oxidase (XO) gene transfection were used to produce various cellular redox levels. 2',7'-dichlorofluorescin (DCF) fluorescence and ESR spectrum were used to detect cellular reactive oxygen species (ROS).</p> <p>Results</p> <p>We found that endogenous or exogenous interference with the cellular oxidative stress can sensitively regulate glycolysis and the Warburg effect in hepatoma cells. Hepatoma cells displayed a high level of free radicals compared to immortalized normal hepatocyte cells. Increasing the level of ROS stress in hepatoma cells can directly upregulate HIF-1 and activate glycolysis without requirement of a hypoxic condition. This explains the mechanism whereby aerobic glycolysis, i.e. the Warburg effect arises. Either endogenously upregulating SOD or exogenously administration with antioxidant can, through downregulating ROS level, effectively regulate energy pathways in hepatoma cells and can inhibit the growth of tumor cells and xenograft tumors.</p> <p>Conclusion</p> <p>This study suggests that the Warburg effect was related to an inherently high level of cellular ROS and HIF-1. Hepatoma cells adaptation to hypoxia for survival and rapid growth exploits oxidative stress ectopically activated glycolysis to compensate the energy supply. This specific mechanism in which tumor cells through cellular oxidative stress activate glycolysis to meet their energy metabolism requirement could be exploited to selectively kill tumor cells.</p

BING: Binarized normed gradients for objectness estimation at 300fps

Training a generic objectness measure to produce object proposals has recently become of significant interest. We observe that generic objects with well-defined closed boundaries can be detected by looking at the norm of gradients, with a suitable resizing of their corresponding image windows to a small fixed size. Based on this observation and computational reasons, we propose to resize the window to 8 × 8 and use the norm of the gradients as a simple 64D feature to describe it, for explicitly training a generic objectness measure. We further show how the binarized version of this feature, namely binarized normed gradients (BING), can be used for efficient objectness estimation, which requires only a few atomic operations (e.g., add, bitwise shift, etc.). To improve localization quality of the proposals while maintaining efficiency, we propose a novel fast segmentation method and demonstrate its effectiveness for improving BING’s localization performance, when used in multithresholding straddling expansion (MTSE) postprocessing. On the challenging PASCAL VOC2007 dataset, using 1000 proposals per image and intersectionover- union threshold of 0.5, our proposal method achieves a 95.6% object detection rate and 78.6% mean average best overlap in less than 0.005 second per image