Utilisation of three-dimensional printed heart models for operative planning of complex congenital heart defects

Background and aim: To evaluate the accuracy of the three-dimensional (3D) printing of cardiovascular structures. To explore whether utilisation of 3D printed heart replicas can improve surgical and catheter interventional planning in patients with complex congenital heart defects. Methods: Between December 2014 and November 2015 we fabricated eight cardiovascular models based on computed tomography data in patients with complex spatial anatomical relationships of cardiovascular structures. A Bland-Altman analysis was used to assess the accuracy of 3D printing by comparing dimension measurements at analogous anatomical locations between the printed models and digital imagery data, as well as between printed models and in vivo surgical findings. The contribution of 3D printed heart models for perioperative planning improvement was evaluated in the four most representative patients. Results: Bland-Altman analysis confirmed the high accuracy of 3D cardiovascular printing. Each printed model offered an improved spatial anatomical orientation of cardiovascular structures. Conclusions: Current 3D printers can produce authentic copies of patients` cardiovascular systems from computed tomography data. The use of 3D printed models can facilitate surgical or catheter interventional procedures in patients with complex congenital heart defects due to better preoperative planning and intraoperative orientation

Methane detection scheme based upon the changing optical constants of a zinc oxide/platinum matrix created by a redox reaction and their effect upon surface plasmons

We detect changes in the optical properties of a metal oxide semiconductor (MOS), ZnO, in a multi-thin-film matrix with platinum in the presence of the hydrocarbon gas methane. A limit of detection of 2% by volume with concentrations from 0 to 10% and maximum resolution of 0.15% with concentrations ranging from 30% to 80% at room temperature are demonstrated along with a selective chemical response to methane over carbon dioxide and the other alkane gases. The device yields the equivalent maximum bulk refractive index spectral sensitivity of 1.8 × 105 nm/RIU. This is the first time that the optical properties of MOS have been monitored to detect the presence of a specific gas. This single observation is a significant result, as MOS have a potentially large number of target gases, thus offering a new paradigm for gas sensing using MOSs

Rank signaling links the development of invariant γδ T cell progenitors and Aire(+) medullary epithelium

The thymic medulla provides a specialized microenvironment for the negative selection of T cells, with the presence of autoimmune regulator (Aire)-expressing medullary thymic epithelial cells (mTECs) during the embryonic-neonatal period being both necessary and sufficient to establish long-lasting tolerance. Here we showed that emergence of the first cohorts of Aire(+) mTECs at this key developmental stage, prior to αβ T cell repertoire selection, was jointly directed by Rankl(+) lymphoid tissue inducer cells and invariant Vγ5(+) dendritic epidermal T cell (DETC) progenitors that are the first thymocytes to express the products of gene rearrangement. In turn, generation of Aire(+) mTECs then fostered Skint-1-dependent, but Aire-independent, DETC progenitor maturation and the emergence of an invariant DETC repertoire. Hence, our data attributed a functional importance to the temporal development of Vγ5(+) γδ T cells during thymus medulla formation for αβ T cell tolerance induction and demonstrated a Rank-mediated reciprocal link between DETC and Aire(+) mTEC maturation

Effective Use of Procedural Shaders in Animated Scenes

Complex procedural shaders are commonly used to enrich the appearance of high-quality computer animations. In traditional rendering architectures the shading computation is performed independently for each animation frame which leads to significant costs. In this paper we propose an approach which eliminates redundant computation between subsequent frames by exploiting temporal coherence in shading. The shadin

Exploiting Temporal Coherence in Ray Casted Walkthroughs

We present a technique that aims at exploiting temporal coherence of ray casted walkthroughs. Our goal is to reuse ray/object intersections computed in the last frame of the walkthrough for acceleration of ray casting in the current frame. In particular we aim at eliminating the ray traversal and computing only a single ray/object intersection per pixel. If our technique does not succeed in determining visibility, it falls back to the classical ray traversal. Visible point samples from the last frame are reprojected to the current frame. To identify whether these samples can be reused we apply splatting and epipolar geometry constraints. We discuss two additional techniques that handle correct appearance of small objects. We conducted a series of tests on walkthroughs of building interiors. Our method succeeded in determining visibility of more than 78% of pixels. For these pixels only a single ray/object intersection is executed. The frame rate is increased by up to 47%. Finally, we argue that the achieved speedup is relatively significant by comparing the performance of our algorithm to the "ideal" ray shooting algorithm

On fast construction of spatial hierarchies for ray tracing

In this paper we address the problem of fast construction of spatial hierarchies for ray tracing with applications in animated environments including non-rigid animations. We discuss properties of currently used techniques with O(N log N) construction time for kd-trees and bounding volume hierarchies. Further, we propose a hybrid data structure blending between a spatial kdtree and bounding volume primitives. We keep our novel hierarchical data structures algorithmically efficient and comparable with kd-trees by the use of a cost model based on surface area heuristics. Although the time complexity O(N log N) is a lower bound required for construction of any spatial hierarchy that corresponds to sorting based on comparisons, using approximate method based on discretization we propose a new hierarchical data structures with expected O(N log log N) time complexity. We also discuss constants behind the construction algorithms of spatial hierarchies important in practice. We document the performance of our algorithms by results obtained from the implementation on nine scenes

Fast Final Gathering via Reverse Photon Mapping

We present a new algorithm for computing indirect illumination based on density estimation similarly to photon mapping. We accelerate the search for final gathering by reorganizing the computation in the reverse order. We use two trees that organize spatially not only the position of photons but also the position of final gather rays. The achieve

Sensing Method Using Multiple Quantities for Diagnostic of Insulators in Different Ambient Conditions

Insulators are one of the many components responsible for the reliability of electricity supply as part of transmission and distribution lines. Failure of the insulator can cause considerable economic problems that are much greater than the insulator cost. When the failure occurs on the transmission line, a large area can be without electricity supply or other transmission lines will be overloaded. Because of the consequences of the insulator’s failure, diagnostics of the insulator plays a significant role in the reliability of the power supply. Basic diagnostic methods require experienced personnel, and inspection requires moving in the field. New diagnostic methods require online measurement if it is possible. Diagnostic by measuring the leakage current flowing on the surface of the insulator is well known. However, many other quantities can be used as a good tool for diagnostics of insulators. We present in this article results obtained on the investigated porcelain insulators that are one of the most used insulation materials for housing the insulator’s core. Leakage current, dielectric loss factor, capacity, and electric charge are used as diagnostic quantities to investigate porcelain insulators in different pollution conditions and different ambient relative humidity. Pollution and humidity are the main factors that decrease the insulator´s electric strength and reliability