Hepatoprotective effects of Paeonia anomala against acetaminophen-induced cell damage through activation of anti-oxidant system

Overdose of the analgesic and anti-pyretic acetaminophen causes a potentially fatal hepatic necrosis due to a high toxicity and depletion of cellular defense mechanisms. In the present work, the potential hepatoprotective effect of the fruit extract of Paeonia anomala against acetaminophen induced cell damages was evaluated in cultured HepG2 cells and compared to the root extract. The fruit extract showed a potent protection against acetaminophen induced cell death, while the root extract showed a weak protection. Particularly, the pre-treatment of lower doses of the fruit extract, 10 μg/ mL and 20 μg/mL, significantly enhanced cell viability. The level of total glutathione in HepG2 cells treated with the fruit extract prior to the treatment of 40 mM acetaminophen was enhanced, however, the root extract failed for this activity. In addition, activities of quinone reductase, glutathione peroxidase and glutathione reductase were increased and protein levels of glutathione peroxidase 1 and superoxide dismutase 1 were enhanced in the cells treated with 10-20 μg/mL of the fruit extract. Furthermore, the protein level of Nrf2, a crucial regulator for detoxifying and antioxidant systems, was increased by the fruit extract treatment. These results suggest that the fruit extract of P. anomala exerts protective effects against acetaminophen-induced toxicity through activation of key antioxidant systems.DOI: http://dx.doi.org/10.5564/mjc.v14i0.190 Mongolian Journal of Chemistry 14 (40), 2013, p.5-1

Triple sign reversal of Hall effect in HgBa_{2}CaCu_{2}O_{6} thin films after heavy-ion irradiations

Triple sign reversal in the mixed-state Hall effect has been observed for the first time in ion-irradiated HgBa_{2}CaCu_{2}O_{6} thin films. The negative dip at the third sign reversal is more pronounced for higher fields, which is opposite to the case of the first sign reversal near T_c in most high-T_c superconductors. These observations can be explained by a recent prediction in which the third sign reversal is attributed to the energy derivative of the density of states and to a temperature-dependent function related to the superconducting energy gap. These contributions prominently appear in cases where the mean free path is significantly decreased, such as our case of ion-irradiated thin films.Comment: 4 pages, 3 eps figures, submitted Phys. Rev. Let

Post-merger Signatures of Red-sequence Galaxies in Rich Abell Clusters at z≲0.1z\lesssim 0.1

We have investigated the post-merger signatures of red-sequence galaxies in rich Abell clusters at $z \lesssim$ 0.1: A119, A2670, A3330 and A389. Deep images in u', g', r' and medium-resolution galaxy spectra were taken using MOSAIC 2 CCD and Hydra MOS mounted on a Blanco 4-m telescope at CTIO. Post-merger features are identified by visual inspection based on asymmetric disturbed features, faint structures, discontinuous halo structures, rings and dust lanes. We found that ~ 25% of bright (M_r < -20) cluster red-sequence galaxies show post-merger signatures in four clusters consistently. Most (~ 71%) of the featured galaxies were found to be bulge-dominated, and for the subsample of bulge-dominated red-sequence galaxies, the post-merger fraction rises to ~ 38%. We also found that roughly 4% of bulge-dominated red-sequence galaxies interact (on-going merger). A total of 42% (38% post-merger, 4% on-going merger) of galaxies show merger-related features. Compared to a field galaxy study with a similar limiting magnitude (van Dokkum 2005), our cluster study presents a similar post-merger fraction but a markedly lower on-going merger fraction. The merger fraction derived is surprisingly high for the high density of our clusters, where the fast internal motions of galaxies are thought to play a negative role in galaxy mergers. The fraction of post-merger and on-going merger galaxies can be explained as follows. Most of the post-merger galaxies may have carried over their merger features from their previous halo environment, whereas interacting galaxies interact in the current cluster in situ. According to our semi-analytic calculation, massive cluster haloes may very well have experienced tens of halo mergers over the last 4-5 Gyr; post-merger features last that long, allowing these features to be detected in our clusters today. (Abridged)Comment: 16 pages, 15 figures, 7 tables, accepted for publication in ApJ

The AzTEC mm-Wavelength Camera

AzTEC is a mm-wavelength bolometric camera utilizing 144 silicon nitride micromesh detectors. Herein we describe the AzTEC instrument architecture and its use as an astronomical instrument. We report on several performance metrics measured during a three month observing campaign at the James Clerk Maxwell Telescope, and conclude with our plans for AzTEC as a facility instrument on the Large Millimeter Telescope.Comment: 13 pages, 15 figures, accepted for publication in Monthly Notice

AzTEC Millimetre Survey of the COSMOS Field - II. Source Count Overdensity and Correlations with Large-Scale Structure

We report an over-density of bright sub-millimetre galaxies (SMGs) in the 0.15 sq. deg. AzTEC/COSMOS survey and a spatial correlation between the SMGs and the optical-IR galaxy density at z <~ 1.1. This portion of the COSMOS field shows a ~ 3-sigma over-density of robust SMG detections when compared to a background, or "blankfield", population model that is consistent with SMG surveys of fields with no extragalactic bias. The SMG over-density is most significant in the number of very bright detections (14 sources with measured fluxes S(1.1mm) > 6 mJy), which is entirely incompatible with sample variance within our adopted blank-field number densities and infers an over-density significance of >> 4. We find that the over-density and spatial correlation to optical-IR galaxy density are most consistent with lensing of a background SMG population by foreground mass structures along the line of sight, rather than physical association of the SMGs with the z <~ 1.1 galaxies/clusters. The SMG positions are only weakly correlated with weak-lensing maps, suggesting that the dominant sources of correlation are individual galaxies and the more tenuous structures in the region and not the massive and compact clusters. These results highlight the important roles cosmic variance and large-scale structure can play in the study of SMGs.Comment: 12 pages, 11 figures, 2 tables, accepted for publication in MNRA

TBK1 regulates regeneration of pancreatic β-cells

Small-molecule inhibitors of non-canonical IκB kinases TANK-binding kinase 1 (TBK1) and IκB kinase ε (IKKε) have shown to stimulate β-cell regeneration in multiple species. Here we demonstrate that TBK1 is predominantly expressed in β-cells in mammalian islets. Proteomic and transcriptome analyses revealed that genetic silencing of TBK1 increased expression of proteins and genes essential for cell proliferation in INS-1 832/13 rat β-cells. Conversely, TBK1 overexpression decreased sensitivity of β-cells to the elevation of cyclic AMP (cAMP) levels and reduced proliferation of β-cells in a manner dependent on the activity of cAMP-hydrolyzing phosphodiesterase 3 (PDE3). While the mitogenic effect of (E)3-(3-phenylbenzo[c]isoxazol-5-yl)acrylic acid (PIAA) is derived from inhibition of TBK1, PIAA augmented glucose-stimulated insulin secretion (GSIS) and expression of β-cell differentiation and proliferation markers in human embryonic stem cell (hESC)-derived β-cells and human islets. TBK1 expression was increased in β-cells upon diabetogenic insults, including in human type 2 diabetic islets. PIAA enhanced expression of cell cycle control molecules and β-cell differentiation markers upon diabetogenic challenges, and accelerated restoration of functional β-cells in streptozotocin (STZ)-induced diabetic mice. Altogether, these data suggest the critical function of TBK1 as a β-cell autonomous replication barrier and present PIAA as a valid therapeutic strategy augmenting functional β-cells