Information-Thermodynamic Bound on Information Flow in Turbulent Cascade

We investigate the nature of information flow in turbulence from an information-thermodynamic viewpoint. For the fully developed three-dimensional fluid turbulence described by the fluctuating Navier-Stokes equation, we prove that information of large-scale eddies is transferred to small scales along with the energy cascade. We numerically illustrate our findings using a shell model and further show that in the inertial range, the intensity of the information flow is nearly constant and can be scaled by the large-eddy turnover time. Our numerical results also suggest that the corresponding information-thermodynamic efficiency is quite low compared to other typical information processing systems such as Maxwell's demon. These findings provide a new perspective on how universality and intermittency of turbulent fluctuations emerge at small scales.Comment: 18 pages, 5 figures. In ver.5, we have extended the main results. The presentation has also been revised substantiall

Space-local Navier--Stokes turbulence

We investigate the physical-space locality of interactions in three-dimensional incompressible turbulent flow. To that, we modify the nonlinear terms of the vorticity equation such that the vorticity field is advected and stretched by the locally induced velocity. This space-local velocity field is defined by the truncated Biot--Savart law, where only the neighboring vorticity field in a sphere of radius $R$ is integrated. We conduct direct numerical simulations of the space-local system to investigate its statistics in the inertial range. We observe a standard $E(k) \propto k^{-5/3}$ scaling of the energy spectrum associated with an energy cascade for scales smaller than the space-local domain size $k \gg R^{-1}$. This result is consistent with the assumption Kolmogorov's 1941 paper made for the space-locality of the nonlinear interactions. The enstrophy production is suppressed for larger scales $k \ll R^{-1}$, and for these scales, the system exhibits a scaling consistent with a conservative enstrophy cascade.Comment: 22 pages, 8 figure

Minimal modeling of the intrinsic cycle of turbulence driven by steady forcing

Quasi-Cyclic Behavior (QCB) is a common feature of various laminar and turbulent flows. We conduct Direct Numerical Simulations (DNS) of three-dimensional flow driven by the steady Taylor--Green forcing to find a silent similarity between a stable periodic flow at a small Reynolds number ($\mathrm{Re}$) and turbulent QCB at higher $\mathrm{Re}$. These two temporal dynamics are continuously connected by varying $\mathrm{Re}$. A close examination of the periodic flow allows the formulation of a simple three-equation model, representing the evolution of Fourier modes in three distinct scales. The model reproduces the continuously connected periodic solution and QCB when $\mathrm{Re}$ is varied. We find that non-local triad interactions are necessary to maintain the periodic solution and QCB. Bifurcation analyses illustrate that the model can also reproduce several critical features of turbulence, such as sudden relaminarization of transient chaos. These findings suggest that the model is not specific to the studied flow in a periodic domain but is of more general importance in investigating turbulence in different flow configurations

Noninvasive Demonstration of Dual Coronary Artery Fistulas to Main Pulmonary Artery with 64-Slice Multidetector-Computed Tomography: A Case Report

Coronary artery fistulas, including coronary pulmonary fistulas, are usually discovered accidently among the adult population when undergoing invasive coronary angiographies. We report here a 58-year-old woman with dual fistulas originating from the left anterior descending coronary artery and right coronary sinus to the main pulmonary artery, demonstrating noninvasively with multidetector-computed tomography (MDCT) and transthoracic echocardiography (TTE)

GEM-TREND: a web tool for gene expression data mining toward relevant network discovery

<p>Abstract</p> <p>Background</p> <p>DNA microarray technology provides us with a first step toward the goal of uncovering gene functions on a genomic scale. In recent years, vast amounts of gene expression data have been collected, much of which are available in public databases, such as the Gene Expression Omnibus (GEO). To date, most researchers have been manually retrieving data from databases through web browsers using accession numbers (IDs) or keywords, but gene-expression patterns are not considered when retrieving such data. The Connectivity Map was recently introduced to compare gene expression data by introducing gene-expression signatures (represented by a set of genes with up- or down-regulated labels according to their biological states) and is available as a web tool for detecting similar gene-expression signatures from a limited data set (approximately 7,000 expression profiles representing 1,309 compounds). In order to support researchers to utilize the public gene expression data more effectively, we developed a web tool for finding similar gene expression data and generating its co-expression networks from a publicly available database.</p> <p>Results</p> <p>GEM-TREND, a web tool for searching gene expression data, allows users to search data from GEO using gene-expression signatures or gene expression ratio data as a query and retrieve gene expression data by comparing gene-expression pattern between the query and GEO gene expression data. The comparison methods are based on the nonparametric, rank-based pattern matching approach of Lamb et al. (Science 2006) with the additional calculation of statistical significance. The web tool was tested using gene expression ratio data randomly extracted from the GEO and with in-house microarray data, respectively. The results validated the ability of GEM-TREND to retrieve gene expression entries biologically related to a query from GEO. For further analysis, a network visualization interface is also provided, whereby genes and gene annotations are dynamically linked to external data repositories.</p> <p>Conclusion</p> <p>GEM-TREND was developed to retrieve gene expression data by comparing query gene-expression pattern with those of GEO gene expression data. It could be a very useful resource for finding similar gene expression profiles and constructing its gene co-expression networks from a publicly available database. GEM-TREND was designed to be user-friendly and is expected to support knowledge discovery. GEM-TREND is freely available at <url>http://cgs.pharm.kyoto-u.ac.jp/services/network</url>.</p

Key particle properties of shells for cadmium chemisorption

Previous studies on cadmium adsorption of calcium carbonate have found that polymorph, and, crystallinity are influential factors for adsorbing cadmium ions. The predominant factor for cadmium adsorption has yet to be elucidated because these factors are linked. To overcome this, here each factor is investigated separately. First, atmospheric grinding prepared surf clam (aragonite phase) and scallop (calcite phase) shells with similar crystallite sizes and specific surface areas. Using adsorption isotherm models, kinetics, X-ray diffraction analysis, and TEM observations, both calcite and aragonite react with cadmium to form cadmium carbonate. The chemisorption follows the adsorption mechanism reported in the literature. Based on the Langmuir isotherm model fitting, the maximum adsorbed amount for the ground surf clam shells is 633.3 mg/g, while that for scallop shells is 195.8 mg/g. Then fine surf clam shell particles with a similar specific surface area, and with a relatively wide range of the aragonite ratio, and crystallite size are prepared via a combination of grinding and a subsequent calcination process. Our experiments where one explanatory variable is changed at a time demonstrate that the polymorph ratio and crystallite size of the ground shells play key roles in the chemisorption

RVS for small lesion in hepatectomy

Background : Systemic chemotherapy can drastically downsize metastatic liver tumors and these small liver lesions could sometimes be difficult for surgeons to detect during hepatectomy. We assessed the usefulness of intraoperative real-time virtual sonography (RVS) with contrast-enhanced ultrasonography (CEUS) using ‘Sonazoid’ contrast agent (RVS-CEUS). Methods : We performed the intraoperative RVS-CEUS technique on 10 tumor lesions in six cases, which were scheduled for hepatic resection of < 10 mm in diameter in our liver metastases series. These lesions were preoperatively diagnosed by contrast enhanced-computed tomography (CE-CT) or Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (EOB-MRI). We assessed the detectability of a tumor with RVS-CEUS during surgery and compared it with that of preoperative CE-CT or EOB-MRI. Results : Detectability of RVS-CEUS for 10 small lesions was 90% (n = 9/10) and that of other preoperative modalities were 50% (n = 5/10, CE-CT) and 100% (n = 10/10, EOB-MRI). Minimum tumor size detected was 3.0 mm in diameter, and maximum depth of detection with RVS-CEUS was 43.5 mm ; these results could be an advantage when compared with other intraoperative diagnostic modalities. Conclusion : Intraoperative RVS-CEUS was useful for detecting small metastatic liver lesions after chemotherapy and could be an effective intraoperative diagnostic technique for hepatic resection of a size < 10 mm

Lamivudine treatment in patients with HBV-related hepatocellular carcinoma--using an untreated, matched control cohort.

Lamivudine is widely used to treat patients with hepatitis B. However, the outcomes in patients with hepatocellular carcinoma (HCC) treated with lamivudine have not been established. This study was conducted to evaluate the outcomes of lamivudine treatment for patients with HCC using an untreated, matched control group. Thirty patients with controlled HCC orally received lamivudine. As controls, 40 patients with HCC who were not treated with lamivudine and matched for clinical features were selected. The lamivudine-treated and untreated groups were compared with respect to changes in liver function, HCC recurrence, survival, and cause of death. In the lamivudine-treated group, there was significant improvement in the Child-Pugh score at 24 months after starting treatment, while no improvement was observed in the untreated group. There was no significant difference in the cumulative incidence of HCC recurrence and survival between the groups. However, there was a significant difference in the cumulative incidence of death due to liver failure (P= 0.043). A significant improvement in liver function was achieved by lamivudine treatment, even in patients with HCC. These results suggest that lamivudine treatment for patients with HCC may prevent death due to liver failure. Further prospective randomized studies using a larger number of patients are required.</p