mab-31 and the TGF-β pathway act in the ray lineage to pattern C. elegans male sensory rays

<p>Abstract</p> <p>Background</p> <p><it>C. elegans </it>TGF-β-like Sma/Mab signaling pathway regulates both body size and sensory ray patterning. Most of the components in this pathway were initially identified by genetic screens based on the small body phenotype, and many of these mutants display sensory ray patterning defect. At the cellular level, little is known about how and where these components work although ray structural cell has been implicated as one of the targets. Based on the specific ray patterning abnormality, we aim to identify by RNAi approach additional components that function specifically in the ray lineage to elucidate the regulatory role of TGF-β signaling in ray differentiation.</p> <p>Result</p> <p>We report here the characterization of a new member of the Sma/Mab pathway, <it>mab-31</it>, recovered from a genome-wide RNAi screen. <it>mab-31 </it>mutants showed ray cell cluster patterning defect and mis-specification of the ray identity. <it>mab-31 </it>encodes a nuclear protein expressed in descendants of ray precursor cells impacting on the ray cell's clustering properties, orientation of cell division plane, and fusion of structural cells. Genetic experiments also establish its relationship with other Sma/Mab pathway components and transcription factors acting upstream and downstream of the signaling event.</p> <p>Conclusion</p> <p><it>mab-31 </it>function is indispensable in Sma/Mab signal recipient cells during sensory rays specification. Both <it>mab-31 </it>and <it>sma-6 </it>are required in ray lineage at the late larval stages. They act upstream of <it>C. elegans Pax-6 </it>homolog and repress its function. These findings suggested <it>mab-31 </it>is a key factor that can integrate TFG-β signals in male sensory ray lineage to define organ identity.</p

Geometric Hardy inequalities for the sub-elliptic Laplacian on convex domains in the Heisenberg group

We prove geometric $L^p$ versions of Hardy's inequality for the sub-elliptic Laplacian on convex domains $\Omega$ in the Heisenberg group $\mathbb{H}^n$, where convex is meant in the Euclidean sense. When $p=2$ and $\Omega$ is the half-space given by $\langle \xi, \nu\rangle > d$ this generalizes an inequality previously obtained by Luan and Yang. For such $p$ and $\Omega$ the inequality is sharp and takes the form \begin{equation} \int_\Omega |\nabla_{\mathbb{H}^n}u|^2 \, d\xi \geq \frac{1}{4}\int_{\Omega} \sum_{i=1}^n\frac{\langle X_i(\xi), \nu\rangle^2+\langle Y_i(\xi), \nu\rangle^2}{\textrm{dist}(\xi, \partial \Omega)^2}|u|^2\, d\xi, \end{equation} where $\textrm{dist}(\, \cdot\,, \partial \Omega)$ denotes the Euclidean distance from $\partial \Omega$.Comment: 14 page

A preclinical study on the combination therapy of everolimus and transarterial chemoembolization in hepatocellular carcinoma

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Population Factors Affecting Initial Diffusion Patterns of H1N1

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An Early Warning System for Detecting H1N1 Disease Outbreak - A Spatio-temporal Approach

The outbreaks of new and emerging infectious diseases in recent decades have caused widespread social and economic disruptions in the global economy. Various guidelines for pandemic influenza planning are based upon traditional infection control, best practice and evidence. This article describes the development of an early warning system for detecting disease outbreaks in the urban setting of Hong Kong, using 216 confirmed cases of H1N1 influenza from 1 May 2009 to 20 June 2009. The prediction model uses two variables – daily influenza cases and population numbers – as input to the spatio-temporal and stochastic SEIR model to forecast impending disease cases. The fairly encouraging forecast accuracy metrics for the 1- and 2-day advance prediction suggest that the number of impending cases could be estimated with some degree of certainty. Much like a weather forecast system, the procedure combines technical and scientific skills using empirical data but the interpretation requires experience and intuitive reasoning.postprin

Effects of geographic scale on population factors in acute disease diffusion analysis

Objective To explore socio-demographic data of the population as proxies for risk factors in disease transmission modeling at different geographic scales. Methods Patient records of confirmed H1N1 influenza were analyzed at three geographic aggregation levels together with population census statistics. Results The study confirmed that four population factors were related in different degrees to disease incidence, but the results varied according to spatial resolution. The degree of association actually decreased when data of a higher spatial resolution were used. Conclusions We concluded that variables at suitable spatial resolution may be useful in improving the predictive powers of models for disease outbreaks.published_or_final_versio

On the Alexandrov Topology of sub-Lorentzian Manifolds

It is commonly known that in Riemannian and sub-Riemannian Geometry, the metric tensor on a manifold defines a distance function. In Lorentzian Geometry, instead of a distance function it provides causal relations and the Lorentzian time-separation function. Both lead to the definition of the Alexandrov topology, which is linked to the property of strong causality of a space-time. We studied three possible ways to define the Alexandrov topology on sub-Lorentzian manifolds, which usually give different topologies, but agree in the Lorentzian case. We investigated their relationships to each other and the manifold's original topology and their link to causality.Comment: 20 page

Over-expression of miR-106b promotes cell migration and metastasis in hepatocellular carcinoma by activating epithelial-mesenchymal transition process

Hepatocellular carcinoma (HCC) is one the the most fatal cancers worldwide. The poor prognosis of HCC is mainly due to the developement of distance metastasis. To investigate the mechanism of metastasis in HCC, an orthotopic HCC metastasis animal model was established. Two sets of primary liver tumor cell lines and corresponding lung metastasis cell lines were generated. In vitro functional analysis demonstrated that the metastatic cell line had higher invasion and migration ability when compared with the primary liver tumor cell line. These cell lines were subjected to microRNA (miRNAs) microarray analysis to identify differentially expressed miRNAs which were associated with the developement of metastasis in vivo. Fifteen human miRNAs, including miR-106b, were differentially expressed in 2 metastatic cell lines compared with the primary tumor cell lines. The clinical significance of miR-106b in 99 HCC clinical samples was studied. The results demonstrated that miR-106b was over-expressed in HCC tumor tissue compared with adjacent non-tumor tissue (p = 0.0005), and overexpression of miR-106b was signficantly correlated with higher tumor grade (p = 0.018). Further functional studies demonstrated that miR-106b could promote cell migration and stress fiber formation by over-expressing RhoGTPases, RhoA and RhoC. In vivo functional studies also showed that over-expression of miR-106b promoted HCC metastasis. These effects were related to the activation of the epithelial-mesenchymal transition (EMT) process. Our results suggested that miR-106b expression contributed to HCC metastasis by activating the EMT process promoting cell migration in vitro and metastasis in vivo. © 2013 Yau et al.published_or_final_versio

Emergence of CD26+ cancer stem cells with metastatic properties in colorectal carcinogenesis

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