123,562 research outputs found
Antifibrotic effects of antioxidant N-acetylcysteine in a mouse model of human hypertrophic cardiomyopathy mutation
No full textThe objective was to determine the effects of antioxidant N-acetylcysteine (NAC) on reversal and attenuation of established interstitial fibrosis in the cardiac troponin T (cTnT) mouse model of human hypertrophic cardiomyopathy (HCM) mutation
Dual Hierarchy for Gravitational n-body
No full textThe n-body problem is the simulation of pair-wise interactions between n objects. This problem appears in many forms, with the classic example being the modeling of gravitational forces between point masses, necessary for cosmological simulations. Many approximation approaches have been devised to reduce the complexity of this problem.t-SNE is a data visualization method that requires repeatedly solving a variant of the n-body problem. A recent paper (An Efficient Dual-Hierarchy t-SNE Minimization, van de Ruit et. al.) proposes a novel algorithm that outperforms other t-SNE minimization methods on medium-scale datasets. The report proves the viability of a dual-traversal method that uses an embedding tree to emit forces and an independent field tree to collect forces. Because the embedding tree is a Linear-BVH and the field tree is an orthtree built to a fixed depth, the overall algorithm has linear complexity.This thesis demonstrates how the dual-tree approach can be adapted for gravitational n-body simulations. Following this, it measures the performance against similar implementations of other algorithms and shows that while the adapted Dual Hierarchy approach is faster than Barnes-Hut, it is outperformed by the Fast Multipole Method on realistic large-scale cosmological datasets.https://github.com/JacksonCampolattaro/n-body Git repository containing an implementation of the adapted Dual Hierarchy algorithm for Gravitational n-body, as well as implementations of several other common algorithms compared against during benchmarking.Computer Engineerin
Phosphazene-Based Covalent Organic Polymer Decorated with NiCo2O4Nanocuboids as a Trifunctional Electrocatalyst: A Unique Replacement for the Conventional Electrocatalysts
No full textDeveloping nonprecious metal-based electrocatalysts to convert water into green fuels (H2 and O2) is key to address urgent climate and energy challenges. We have prepared an electrocatalyst by the immobilization of NiCo2O4 on a phosphazene-based covalent organic polymer (P-COP) through a facile hydrothermal method. The elemental composition of the P-COP showed the presence of a greater amount of heteroatoms N (6.62%) and P (5.62%) throughout the polymer support. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were utilized to determine the atomic structure of the nanocuboids, which depicted the formation of an inverse spinel structure. A NiCo2O4-P-COP-based electrode was simultaneously used for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), and it displayed a minimum overpotential of 270 and 130 mV (V vs RHE), respectively, at a current density of 10 mA cm-2. In addition, it acted as an oxygen reduction catalyst with a half-wave potential of 0.83 V (V vs RHE) and a maximum current density of 4.5 mA cm-2. The electrocatalytic activity is comparable with that of the commercially available Pt and RuO2 catalysts. The combined experimental and computational studies confirm that the catalytic centers formed through the interaction between the heteroatoms (N and P) in the phosphazene matrix and metal oxides (Co and Ni) play an important role in its improved durability and electrocatalytic activity
A note on mapping class group actions on derived categories
No full textLet Xnbe a cycle of n projective lines and Tn a symplectic torus with n punctures. Using the theory of spherical twists introduced by Seidel and Thomas, the author will define an action of the pure mapping class group of Tn on Db(Coh(Xn)). The motivation comes from homological mirror symmetry for degenerate elliptic curves, which was studied by the author with Treumann and Zaslow
Reactions of n,n-dibromobenzenesulfonamide with alcohols and mercaptans, 1971
No full textN,N-Dibromobenzenesulfonamide reacts with primary alcohols in a 1:2 molar ratio to yield the esters of the alcohols. The reaction is believed to proceed via a free radical mechanism to generate the reac-tive acylbromide species which then reacts with another mole of the alcohol to yield the ester as the final product. Benzyl alcohol and short chain primary alcohols give the corresponding aldehydes as side reactions. NNDBS reacts with secondary alcohols to give ketones and alpha bromoketones. No reaction takes place with tertiary alcohols. N,N-Dibromobenzenesulfonamide reacts with primary, secondary and tertiary mercaptans to yield the disulfide of the mercaptans in each case. When molecular bromine was used as the brominating agent, the alcohols did not react but the corresponding disulfide was obtained from each mercaptan
Experimental investigation into the effect of substrate clamping on the piezoelectric behaviour of thick-film PZT elements
No full textThis paper details an experimental investigation of the clamping effect associated with thick-film piezoelectric elements printed on a substrate. The clamping effect reduces the measured piezoelectric coefficient, d33, of the film. This reduction is due to the influence of the d31 component in the film when a deformation of the structure occurs, by either the direct or indirect piezoelectric effect. Theoretical analysis shows a reduction in the measured d33 of 62%, i.e. a standard bulk lead zirconate titanate (PZT)-5H sample with a manufacturer specified d33 of 593pC/N would fall to 227.8pC/N. To confirm this effect, the d33 coefficients of five thin bulk PZT-5H samples of 220µm thickness were measured before and after their attachment to a metallized 96% alumina substrate. The experimental results show a reduction in d33 of 74% from 529pC/N to 139pC/N. The theoretical analysis was then applied to existing University of Southampton thick-film devices. It is estimated that the measured d33 value of 131pC/N of the thick-film devices is the equivalent of an unconstrained d33 of 345pC/N
Whispering gallery mode selection in optical bottle microresonators
No full textWe demonstrated a method to excite selected whispering gallery modes in optical bottle microresonators (BMR) by inscribing microgroove scars on their surface by focused ion beam milling. Substantial spectral clean-up is obtained in appropriately scarred BMRs, providing the potential for high performance sensors and other optical devices
Supplemental Material - Prevalence of Primary Liver Cancer is Affected by Place of Birth in Hispanic People Residing in the United States: All of Us Research Program Report
No full textSupplemental Material for Prevalence of Primary Liver Cancer is Affected by Place of Birth in Hispanic People Residing in the United States: All of Us Research Program Report by Jingjing Yu, MD, Brittany G. Sullivan, MD, Girish N. Senthil, Amber Gonda, PhD, Farideh Dehkordi-Vakil, PhD, Belinda Campos, PhD, Farshid Dayyani, MD, and Maheswari Senthil, MD in The American Surgeon</p
Cavity alteration of whispering-gallery mode optical fibre microresonators with high precision CO2 laser
No full textAlteration to the cavity of whispering-gallery mode fibre based optical microresonators are demonstrated with the utilization of high precision CO2 laser. The altered microcavity shows beneficial spectral features for advance photonics applications with Q-factor value of up to 10^6
Optical excitation and probing of whispering gallery modes in bottle microresonators: potential for all-fiber add-drop filters
No full textWe have investigated the optical excitation and probing of bottle microresonators experimentally, using fiber tapers. The channel-dropping characteristics of such devices are shown to depend on the excitation configuration. In addition, the axial leakage behavior of these microresonators is characterized
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