Emergence of topological phases from the extension of two-dimensional lattice with nonsymmorphic symmetries

Young and Kane have given a great insight for 2D Dirac semimetals with nontrivial topology in the presence of nonsymmorphic crystalline symmetry. Based on one of 2D nonsymmorphic square lattice structures they proposed, we further construct a set of 3D minimal tight-binding models via vertically stacking the 2D nonsymmorphic lattice. Specifically, our model provides a platform to generate three topologically semimetallic phases such as Dirac nodal line semimetals, Weyl nodal line semimetals and Weyl semimetals. The off-centered mirror symmetry sufficiently protects nodal lines emerging within mirror-invariant plane with a nontrivial mirror invariant $n_{M\mathbb{Z}}$, whereas twofold screw rotational symmetry protects nontrivial Weyl nodal points with topological charge $C=2$. Interestingly, Weyl nodal loops are generated without mirror symmetry protection, where nontrivial "drumhead" surface states emerge within loops. In the presence of both time-reversal and inversion symmetries, the emergence of weak topological insulator phases is discussed as well.Comment: 8 pages, 6 figures and 1 tabl

Automatic and Interactive Mesh to T-Spline Conversion

In Geometry Processing, and more specifically in surface approximation, one of the most important issues is the automatic generation of a quad-dominant control mesh from an arbitrary shape (e.g. a scanned mesh). One of the first fully automatic solutions was proposed by Eck and Hoppe in 1996. However, in the industry, designers still use manual tools (see e.g. cyslice). The main difference between a control mesh constructed by an automatic method and the one designed by a human user is that in the second case, the control mesh follows the features of the model. More precisely, it is well known from approximation theory that aligning the edges with the principal directions of curvature improves the smoothness of the reconstructed surface, and this is what designers intuitively do. In this paper, our goal is to automatically construct a control mesh driven by the anisotropy of the shape, mimicking the mesh that a designer would create manually. The control mesh generated by our method can be used by a wide variety of representations (splines, subdivision surfaces...). We demonstrate our method applied to the automatic conversion from a mesh of arbitrary topology into a T-Spline surface. Our method first extracts an initial mesh from a PGP (Periodic Global Parameterization). To facilitate user-interaction, we extend the PGP method to take into account optional user-defined information. This makes it possible to locally tune the orientation and the density of the control mesh. The user can also interactively remove edges or sketch additional ones. Then, from this initial control mesh, our algorithm generates a valid T-Spline control mesh by enforcing some validity constraints. The valid T-Spline control mesh is finally fitted to the original surface, using a classic regularized optimization procedure. To reduce the L-infinity approximation error below a user-defined threshold, we iteratively use the T-Spline adaptive local refinement

Mesh Editing with an Embedded Network of Curves

http://ieeexplore.ieee.orgWe propose a method for uncalibrated stereo matching. The method applies gradual elastic deformation to the line segments in a pair of images until they match with each other. By using an energy function and a neighborhood function, matching is performed in a coarse-to-fine manner. Our method gives point correspondences with a low proportion of outliers and is robust in the uncalibrated case (with no need to estimate the epipolar geometry). The computation complexity is proportional to the square of the number of line segments in the images, which is relatively efficient compared with other elaborate methods

Breakthrough in basin modeling using time/space frame

International audienceA new way to model basins that couples the new space-time mathematical framework (defined as the UVT transform) and 3D restoration allows for easy and realistic construction of 4D models. Using models built with the UVT transform, basin modelers will not only include faults and erosional surface properly in all structural settings, but also restore them using a 3D geomechanical finite element engine to model the proper paleo-basin geometries. As the UVT model is being restored, a "hybrid" grid carrying the static and dynamic properties is fully restored. The basin simulation software then takes all the time-dependent geological models and performs its computations on the 4D grid. The goals of basin modeling are to find out whether the oil window was reached, to locate possible traps, and to estimate the volume and quality of hydrocarbons initially generated, migrated, and trapped, as well as to estimate pressure and temperatures in the reservoir (Rudkiewicz et al., 2000). To achieve this, a full subsurface geologic model must be constructed and restored from the source rock to the current topography. Currently, a 4D basin model is a simple horizon based layer cake grid where faults are not represented explicitly as discontinuities. The reconstruction through time is based on the vertical back-stripping of layers. This is limited because the displacement of the blocks along the fault planes cannot be modeled and the material on both sides of reverse faults cannot be represented. The estimation of migration paths across faults can be inaccurate especially in compressive basins or in extensive basins with long offset listric faults.In addition to the limitations in properly representing the model at a given time step, the evolution of the basin as a function of time is done through the simple back-stripping and flattening of layers. So, this paleo-basin geometry can be inaccurate

Functional Effects of let-7g Expression in Colon Cancer Metastasis.

MicroRNA regulation is crucial for gene expression and cell functions. It has been linked to tumorigenesis, development and metastasis in colorectal cancer (CRC). Recently, the let-7 family has been identified as a tumor suppressor in different types of cancers. However, the function of the let-7 family in CRC metastasis has not been fully investigated. Here, we focused on analyzing the role of let-7g in CRC. The Cancer Genome Atlas (TCGA) genomic datasets of CRC and detailed data from a Taiwanese CRC cohort were applied to study the expression pattern of let-7g. In addition, in vitro as well as in vivo studies have been performed to uncover the effects of let-7g on CRC. We found that the expression of let-7g was significantly lower in CRC specimens. Our results further supported the inhibitory effects of let-7g on CRC cell migration, invasion and extracellular calcium influx through store-operated calcium channels. We report a critical role for let-7g in the pathogenesis of CRC and suggest let-7g as a potential therapeutic target for CRC treatment

Periodic Global Parameterization

We present a new globally smooth parameterization method for triangulated surfaces of arbitrary topology. Given two orthogonal piecewise linear vector fields defined over the input mesh (typically the estimated principal curvature directions), our method computes two piecewise linear periodic functions, aligned with the input vector fields, by minimizing an objective function. The bivariate function they define is a smooth parameterization almost everywhere on the surface, except in the vicinity of singular vertices, edges and triangles, where the derivatives of the parameterization vanish. We extract a quadrilateral chart layout from the parameterization function and propose an automatic procedure to detect the singularities, and fix them by splitting and re-parameterizing the containing charts. Our method can construct both quasi-conformal (angle preserving) and quasi-isometric (angle and area preserving) parameterizations. The more restrictive class of quasi-isometric parameterizations is constructed at the expense of introducing more singularities. The constructed parameterizations can be used for a variety of geometry processing applications. Since we can align the parameterization with the principal curvature directions, our result is particularly suitable for surface fitting and remeshing

Minimal clinically important difference of the EORTC QLQ-CIPN20 for worsening peripheral neuropathy in patients receiving neurotoxic chemotherapy.

Context/objectivesThis is the first study to determine the minimal clinically important difference (MCID) of the European Organisation of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN twenty-item scale (EORTC QLQ-CIPN20), a validated instrument designed to elicit cancer patients' experience of symptoms and functional limitations related to chemotherapy-induced peripheral neuropathy.MethodsCancer patients receiving neurotoxic chemotherapy completed EORTC QLQ-CIPN20 and the Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity [FACT/GOG-NTX] at baseline, second cycle of chemotherapy (T2, n = 287), and 12 months after chemotherapy (T3, n = 191). Anchor-based approach used the validated FACT/GOG-NTX neurotoxicity (Ntx) subscale to identify optimal MCID cutoff for deterioration. Distribution-based approach used one-third standard deviation (SD), half SD, and one standard error of measurement of the total EORTC QLQ-CIPN20 score.ResultsThere was a moderate correlation between the change scores of the Ntx subscale and sensory and motor subscales of QLQ-CIPN20 (T2: r = - 0.722, p < 0.001 and r = - 0.518, p < 0.001, respectively; T3: r = - 0.699; p < 0.001 and r = - 0.523, p < 0.001, respectively). The correlation between the change scores of the Ntx subscale and the QLQ-CIPN20 autonomic subscale was poor (T2: r = - 0.354, p < 0.001; T3: r = 0.286, p < 0.001). Based on the MCID derived using distribution-based method, the MCID for the QLQ-CIPN20 sensory subscale was 2.5-5.9 (6.9% to 16.4% of the subdomain score) and for motor subscale was 2.6-5.0 (8.1%-15.6% of the subdomain score).ConclusionThe MCID for the EORTC QLQ-CIPN20 established using distribution-based approaches was 2.5-5.9 for the sensory subscale and 2.6-5.0 for the motor subscale. When noted in assessments even with small change in scores, clinicians can be alerted for appropriate intervention