Testing RIAF model for Sgr A* using the size measurements

Recent radio observations by the VLBA at 7 and 3.5 mm produced the high-resolution images of the compact radio source located at the center of our Galaxy--Sgr A*, and detected its wavelength-dependent intrinsic sizes at the two wavelengths. This provides us with a good chance of testing previously-proposed theoretical models for Sgr A*. In this {\em Letter}, we calculate the size based on the radiatively inefficient accretion flow (RIAF) model proposed by Yuan, Quataert & Narayan (2003). We find that the predicted sizes after taking into account the scattering of the interstellar electrons are consistent with the observations. We further predict an image of Sgr A* at 1.3 mm which can be tested by future observations.Comment: 10 pages, 1 figure; accepted by ApJ

Imidazole-thiazolidinone inhibits oesophageal cancer cell proliferation via induction of apoptosis and cell cycle arrest at S phase

Purpose: To investigate the effect of imidazole-thiazolidinone on oesophageal cancer (OC) cell proliferation, and the mechanism of action involved.Methods: Human OC cells (HCE-6 and KYSE-1170) were cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10 % fetal bovine serum (FBS) and 1 % penicillin/streptomycin solution at 37 ˚C for 24 h in a humidified atmosphere of 5 % CO2 and 95 % air. After attaining 60 -  70 % confluency, the cells were treated with serum-free medium and graded concentrations of imidazolethiazolidinone (up to 160 μM) for 24 h. Normal cell culture without imidazole-thiazolidinone served as control. Cells in logarithmic growth phase were selected and used in this study. Cell proliferation and apoptosis were assessed using 3 (4,5 dimethyl thiazol 2 yl) 2,5 diphenyl 2H tetrazolium bromide (MTT), and flow cytometric assays, respectively. The levels of expression of apoptosis-related proteins were determined using Western blotting.Results: Treatment of HCE-6 and KYSE-1170 cells with imidazole-thiazolidinone for 48 h led to significant and dose-dependent reduction in their  proliferation, as well as significant and dosedependent increase in the number of apoptotic cells (p < 0.05). Light microscopy revealed significantreduction in HCE-6 cell count, detached cells, reduced cell size and irregular cytoplasmic vacuoles. Imidazole-thiazolidinone treatment significantly and dose-dependently decreased HCE-6 and KYSE-1170 cell migration, and arrested HCE-6 cell cycle at S phase (p < 0.05). In HCE-6 cells, imidazolethiazolidinone treatment significantly and dose-dependently upregulated the expressions of cleaved caspase-3/8/9 and bax, but down-regulated bcl-2 expression significantly and dose-dependently (p < 0.05). However, metalloproteinases 2 and 9 (MMP-2 and MMP-9) expressions in HCE-6 and KYSE-1170 cells were significantly and dose-dependently down-regulated by imidazole-thiazolidinone treatment (p < 0.05).Conclusion: The results obtained in this study suggest that imidazole-thiazolidinone suppresses OC cell proliferation via induction of apoptosis and arrest of cell cycle at S phase. Keywords: Imidazole-thiazolidinone, Oesophageal cancer, Metastasis, Cell cycle arrest, Apoptosi

Engineering analysis of biological variables: An example of blood pressure over 1 day

Almost all variables in biology are nonstationarily stochastic. For these variables, the conventional tools leave us a feeling that some valuable information is thrown away and that a complex phenomenon is presented imprecisely. Here, we apply recent advances initially made in the study of ocean waves to study the blood pressure waves in the lung. We note first that, in a long wave train, the handling of the local mean is of predominant importance. It is shown that a signal can be described by a sum of a series of intrinsic mode functions, each of which has zero local mean at all times. The process of deriving this series is called the “empirical mode decomposition method.” Conventionally, Fourier analysis represents the data by sine and cosine functions, but no instantaneous frequency can be defined. In the new way, the data are represented by intrinsic mode functions, to which Hilbert transform can be used. Titchmarsh [Titchmarsh, E. C. (1948) Introduction to the Theory of Fourier Integrals (Oxford Univ. Press, Oxford)] has shown that a signal and i times its Hilbert transform together define a complex variable. From that complex variable, the instantaneous frequency, instantaneous amplitude, Hilbert spectrum, and marginal Hilbert spectrum have been defined. In addition, the Gumbel extreme-value statistics are applied. We present all of these features of the blood pressure records here for the reader to see how they look. In the future, we have to learn how these features change with disease or interventions

Testing the Accretion Flow with Plasma Wave Heating Mechanism for Sagittarius a* by the 1.3MM Vlbi Measurements

The vicinity of the supermassive black hole associated with the compact radio source Sagittarius (Sgr) A* is believed to dominate the observed emission at wavelengths near and shorter than $\sim$ 1 millimeter. We show that a general relativistic accretion flow, heated via the plasma wave heating mechanism, is consistent with the polarization and recent mm-VLBI observations of Sgr A* for an inclination angle of $\sim 45^\circ$, position angle of $\sim 140^\circ$, and spin $\lesssim 0.9$. Structure in visibilities produced by the black hole shadow can potentially be observed by 1.3 mm-VLBI on the existing Hawaii-CARMA and Hawaii-SMT baselines. We also consider eight additional potential mm-VLBI stations, including sites in Chile and New Zealand, finding that with these the basic geometry of the emission region can be reliably estimated.Comment: ApJ accepted; 21 pages, 8 figure

Mesomorphic Lamella Rolling of Au in Vacuum

Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241–0.192 nm) and the nearest neighbor distance (ca. 0.74–0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458–0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon–hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration

Three-dimensional structure of the milky way dust: modeling of LAMOST data

We present a three-dimensional modeling of the Milky Way dust distribution by fitting the value-added star catalog of LAMOST spectral survey. The global dust distribution can be described by an exponential disk with scale-length of 3,192 pc and scale height of 103 pc. In this modeling, the Sun is located above the dust disk with a vertical distance of 23 pc. Besides the global smooth structure, two substructures around the solar position are also identified. The one located at $150^{\circ}<l<200^{\circ}$ and $-5^{\circ}<b<-30^{\circ}$ is consistent with the Gould Belt model of \citet{Gontcharov2009}, and the other one located at $140^{\circ}<l<165^{\circ}$ and $0^{\circ}<b<15^{\circ}$ is associated with the Camelopardalis molecular clouds.Comment: 15 pages, 6 figure, accepted by Ap