Combined use of repeated active shots and ambient noise to detect temporal changes in seismic velocity: application to Sakurajima volcano, Japan

Additional file 1. Comparison of the results of coda-wave interferometry and seismic interferometry on the almost identical wave paths. Gray dots in top two panels are daily dv/v values obtained from seismic interferometry. The dv/v values obtained from coda-wave interferometry are shown by red squares and are overwritten assuming that the results for the 2012 experiment are the same as those on the same day from seismic interferometry. Error bars show Âą one standard deviation. Spatial distribution of three seismometers (squares) and a shot point (star) used in top two panels is shown in the bottom panel with black letters and red letters, respectively

β(2)-Adrenergic and M(2)-muscarinic receptors decrease basal t-tubular L-type Ca2+ channel activity and suppress ventricular contractility in heart failure

L-Lype Ca2+ channels (LTCC) play a crucial role in cardiac excitation-contraction coupling. We previously found that in failing ventricular myocytes of mice chronically treated with isoproterenol, basal t-tubular (TT) LTCC activity was halved by activation of protein phosphatase (PP)2A whereas basal surface sarcolemmal (SS) LTCC activity was doubled by inhibition of PP1. Interestingly, chronic treatment of these mice with pertussis toxin almost completely normalized TT and SS LTCC densities and cardiac contractility. In the present study, we therefore sought to identify the G(i/o) protein coupled receptors in cardiac myocytes (i.e. beta(2)-adrenergic, M-2-muscarinic and A(1)-adenosine receptors) that are responsible for these abnormalities in heart failure by chronically administrating mice a selective antagonist of each receptor (ICI118,551, atropine and 8-cyclopentyl-1,3-dipropilxanthine (DPCPX), respectively) with isoproterenol. Compared with mice treated with isoproterenol alone, mice treated with isoproterenol plus ICI118,551 or atropine, but not DPCPX showed significantly lower lung weight/tibial length, higher fractional shortening, lower left ventricular end-diastolic pressure and higher dP/dt(max) and dP/dt(min). In addition, ventricular myocytes of mice treated with isoproterenol plus ICI118,551 or atropine, but not DPCPX exhibited significantly higher TT and lower SS LTCC current densities than those of mice treated with isoproterenol alone due to normalization of the PP activities. These results indicate that beta(2)-adrenergic, M-2-muscarinic, but not A(1)-adenosine receptors contribute to reduced ventricular contractility at least partially by decreasing basal TT LTCC activity in heart failure. Therefore, antagonists of beta(2)-alrenergic and/or M-2-muscarinic receptors can be good adjuncts to beta(1)-adrenergic receptor antagonists in the treatment of heart failure.ArticleEUROPEAN JOURNAL OF PHARMACOLOGY. 724:122-131 (2014)journal articl

Identification of an inter-transcription factor regulatory network in human hepatoma cells by Matrix RNAi

Transcriptional regulation by transcriptional regulatory factors (TRFs) of their target TRF genes is central to the control of gene expression. To study a static multi-tiered inter-TRF regulatory network in the human hepatoma cells, we have applied a Matrix RNAi approach in which siRNA knockdown and quantitative RT-PCR are used in combination on the same set of TRFs to determine their interdependencies. This approach focusing on several liver-enriched TRF families, each of which consists of structurally homologous members, revealed many significant regulatory relationships. These include the cross-talks between hepatocyte nuclear factors (HNFs) and the other TRF groups such as CCAAT/enhancer-binding proteins (CEBPs), retinoic acid receptors (RARs), retinoid receptors (RXRs) and RAR-related orphan receptors (RORs), which play key regulatory functions in human hepatocytes and liver. In addition, various multi-component regulatory motifs, which make up the complex inter-TRF regulatory network, were identified. A large part of the regulatory edges identified by the Matrix RNAi approach could be confirmed by chromatin immunoprecipitation. The resultant significant edges enabled us to depict the inter-TRF TRN forming an apparent regulatory hierarchy of (FOXA1, RXRA) → TCF1 → (HNF4A, ONECUT1) → (RORC, CEBPA) as the main streamline

Locating Spatial Changes of Seismic Scattering Property by Sparse Modeling of Seismic Ambient Noise Cross-Correlation Functions: Application to the 2008 Iwate-Miyagi Nairiku (Mw 6.9), Japan, Earthquake

International audienceLocating change regions of seismic velocities and seismic scattering properties associated with volcanic activities and earthquakes is important for structural monitoring. To increase such applications, we propose to use sparse modeling to estimate spatial distributions of seismic scattering property changes. The sparse modeling is an inversion technique that enables us to estimate model parameters from a small data set with sparsity condition such as 1 norm regularization. We apply this technique to seismic ambient noise cross-correlation functions from 17 Hi-net stations around the epicenter of the 2008 Iwate-Miyagi Nairiku, Japan, earthquake (Mw = 6.9). We compute waveform decoherences at the 0.5-1 Hz band and invert the waveform decoherences for the spatial distributions of seismic scattering property changes. Just after the main shock, the largest change occurred at the south of the epicenter, and the maximum change of the scattering coefficient in this region is estimated to be 0.032 km −1. The result from an ordinary linear least squares inversion with the 2 norm regularization is almost consistent with that from the sparse modeling. Moreover, we confirm the superiority of sparse modeling in imaging with smaller data sets. Only five seismic stations that are deployed near the epicenter so as to surround the change regions are necessary to retrieve the result from 17 stations. On the other hand, in the case of the 2 norm regularization, we need at least 15 stations. The sparse modeling will be helpful to estimate the spatial distribution of seismic scattering property changes from a small data set

Statistical characteristics of seismic velocity changes measured by seismic interferometry

Seismic interferometry is a technique to retrieve Green’s functions between two points from crosscorrelation functions of seismic ambient noise records at the two points. This technique has been widely used to monitor seismic velocities in the Earth and succeeded in detecting changes inassociation with large earthquakes and/or volcanic eruptions. However, in doing such monitoring, it is important to judge if a current seismic velocity change is significant or not. We here propose a statistical method for that purpose. First, we study statistical distributions of seismic velocity changes observed during normal periods when no large earthquakes or volcanic eruptions are known to have occurred. Then, we assign a probability to a current value of seismic velocity change using these statistical distributions. Accordingly, we can objectively judge if the current value is normal or abnormal. Analyzing three different data sets of seismic velocities measured in Japan with seismic interferometry, we find that the Gaussian distribution well explains most of the datasets. However, an exception is the truncated Cauchy distribution that accounts for the dataset in lower frequency bands at Sakurajima volcano. Once the statistical distribution is known, whichever it is Gaussian or other distributions, we can quantify the monitoring of seismic velocity changes based on probabilities. That is also useful for automatic detections of anomalies in seismic velocity changes

Neurogenic tumors of the mediastinum and chest wall: MR imaging appearance.

Various histologic types of neurogenic tumors may originate in the mediastinum and chest wall. It is possible to make accurate diagnosis of these tumors by using the multiplanar capability and high contrast resolution of MR imaging because of these characteristic imaging findings. MR and histologic features of these tumors are illustrated and described in this essay.Various histologic types of neurogenic tumors may originate in the mediastinum and chest wall. It is possible to make accurate diagnosis of these tumors by using the multiplanar capability and high contrast resolution of MR imaging because of these characteristic imaging findings. MR and histologic features of these tumors are illustrated and described in this essay