482 research outputs found

    PHIDL: Python CAD layout and geometry creation for nanolithography

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    Computer-aided design (CAD) has become a critical element in the creation of nanopatterned structures and devices. In particular, with the increased adoption of easy-to-learn programming languages like Python there has been a significant rise in the amount of lithographic geometries generated through scripting and programming. However, there are currently unaddressed gaps in usability for open-source CAD tools -- especially those in the GDSII design space -- that prevent wider adoption by scientists and students who might otherwise benefit from scripted design. For example, constructing relations between adjacent geometries is often much more difficult than necessary -- spacing a resonator structure a few micrometers from a readout structure often requires manually-coding the placement arithmetic. While inconveniences like this can be overcome by writing custom functions, they are often significant barriers to entry for new users or those less familiar with programming. To help streamline the design process and reduce barrier to entry for scripting designs, we have developed PHIDL, an open-source GDSII-based CAD tool for Python 2 and 3

    Announcing the Minderoo - Monaco Commission on Plastics and Human Health.

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    © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Landrigan, P., Raps, H., Symeonides, C., Chiles, T., Cropper, M., Enck, J., Hahn, M., Hixson, R., Kumar, P., Mustapha, A., Park, Y., Spring, M., Stegeman, J., Thompson, R., Wang, Z., Wolff, M., Yousuf, A., & Dunlop, S. Announcing the Minderoo – Monaco Commission on Plastics and Human Health. Annals of Global Health, 88(1), (2022): 73, https://doi.org/10.5334/aogh.3916.Plastic is the signature material of our age. In the 75 years since large-scale production began in the aftermath of World War II, plastic has transformed our world, supported many of the most significant advances of modern civilization, and enabled breakthroughs in virtually every field of human endeavor. But plastic also poses great and growing dangers to human health and the environment, harms that fall disproportionately on the world’s poorest and most vulnerable populations. The extent and magnitude of these dangers are only beginning to be understood.The funding is from the Minderoo Foundation, the Centre Scientifique de Monaco, and the Prince Albert II of Monaco Foundation

    Imaging myocardial carcinoid with T2-STIR CMR

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    We used T2-STIR (Short Tau Inversion Recovery) cardiovascular magnetic resonance to demonstrate carcinoid tumor metastases to the heart and liver in a 64-year-old woman with a biopsy-proven ileal carcinoid tumor who was referred because of an abnormal echocardiogram

    Does Al4H14— cluster anion exist? High-level ab initio study

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    A comprehensive ab initio investigation using coupled cluster theory with the aug-cc-pVnZ, n = D,T basis sets is carried out to identify distinct structures of the Al4H14— cluster anion and to evaluate its fragmentation stability. Both thermodynamic and mechanistic aspects of the fragmentation reactions are studied. The observation of this so far the most hydrogenated aluminum tetramer was reported in the recent mass spectrometry study of Li et al. (2010) J Chem Phys 132:241103–241104. The four Al4H14— anion structures found are chain-like with the multiple-coordinate Al center and can be viewed approximately as comprising Al2H7— and Al2H7 moieties. Locating computationally some of the Al4H14— minima on the correlated ab initio potential energy surfaces required the triple-zeta quality basis set to describe adequately the Al multi-coordinate bonding. For the two most stable Al4H14— isomers, the mechanism of their low-barrier interconversion is described. The dissociation of Al4H14— into the Al2H7— and Al2H7 units is predicted to require 20-22 (10-13) kcal mol-1 in terms of ΔH (ΔG) estimated at T = 298.15 K and p = 1 atm. However, Al4H14— is found to be a metastable species in the gas phase: the H2 loss from the radical moiety of its most favorable isomer is exothermic by 18 kcal mol-1 in terms of ΔH (298.15 K) and by 25 kcal mol-1 in terms of ΔG(298.15 K), with the enthalpic/free energy barrier involved being less than 1 kcal mol-1. By contrast with alane Al4H14—, only a weakly bound complex between Ga4H12— and H2 has been identified for the gallium analogue using the relativistic effective core potential
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