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Recently, interest in fractional‐order inductors (FOIs) has increased since they allow for accurate and robust models of dynamical systems to be designed. However, practical implementation of these models has not been possible due to the lack of single FOI realizations. To address this challenge, in this work, we propose a simple‐to‐realize fractional‐order inductor design with variable constant phase angle (CPA). The design relies on characteristics of transverse electromagnetic (TEM) mode propagating on a coaxial structure filled with conductive material, more specifically NaCl‐water solution and flour‐based mixtures. The CPA of the resulting FOI can be tuned by changing the conductivity of the dough mixture. Analysis of the proposed FOI design show that the CPA can vary in a range from 0° to 90°. Two of these CPA values are verified against experiments in the frequency band changing from 1 to 10 MHz. [ABSTRACT FROM AUTHOR]

Duchenne muscular dystrophy (DMD) is an X-linked disorder caused by loss of function mutations in the dystrophin gene (Dmd), resulting in progressive muscle weakening. Here we modelled the longitudinal expression of endogenous Dmd, and its paralogue Utrn, in mice and in myoblasts by generating bespoke bioluminescent gene reporters. As utrophin can partially compensate for Dmd-deficiency, these reporters were used as tools to ask whether chromatin-modifying drugs can enhance Utrn expression in developing muscle. Myoblasts treated with different PRC2 inhibitors showed significant increases in Utrn transcripts and bioluminescent signals, and these responses were independently verified by conditional Ezh2 deletion. Inhibition of ERK1/2 signalling provoked an additional increase in Utrn expression that was also seen in Dmd-mutant cells, and maintained as myoblasts differentiate. These data reveal PRC2 and ERK1/2 to be negative regulators of Utrn expression and provide specialised molecular imaging tools to monitor utrophin expression as a therapeutic strategy for DMD. With the long-term goal of finding therapeutic options for Duchenne muscular dystrophy, a mouse model enabling simultaneous visualisation of Dmd and Utrn is described and inhibitors of PRC2 and ERK1/2 identified to increase utrophin expression. [ABSTRACT FROM AUTHOR]

A multitrace surface integral equation (MT-SIE) solver is proposed to analyze electromagnetic field interactions on composite devices involving magnetized and nonmagnetized graphene sheets. The computation domain is decomposed into two subdomains: an exterior subdomain that represents the unbounded background medium where the device resides in an interior subdomain that represents the dielectric substrate. Resistive Robin transmission conditions (RRTCs) are formulated to describe the infinitesimally thin graphene sheet that partially covers the surface between the two subdomains. On the rest of this surface, traditional Robin transmission conditions (RTCs) are enforced. The electric and magnetic field equations are used as the governing equations in each subdomain. The governing equations of a subdomain are locally coupled to the governing equations of its neighbor using RRTCs and RTCs. The accuracy and the applicability of the proposed MT-SIE solver are demonstrated by various numerical examples. [ABSTRACT FROM AUTHOR]

In this work, to characterize the radiated emission from electronic circuits in shielding enclosure, an improved electric dipole-based source reconstruction method (SRM) is developed. Moreover, by resorting to this reconstructed equivalent source, the estimation of electromagnetic interference (EMI) between different circuit modules in the enclosure can be conveniently and accurately evaluated. Different from the free-space SRM, the equivalent dipoles of the proposed SRM are directly placed over the shielding box enclosed circuit board, and the numerical Green’s function (NGF) is developed to bridge the connection between the equivalent dipoles and the planar scanned magnetic near-field. With the NGF strategy, the effects of surrounding environments (including the presence of substrate, ground plane, and shielding enclosure) are inclusively considered, which makes the proposed SRM valid for any complex EM environments in theory. Since the proposed SRM also has the capability of reproducing the radiated emission inside the shielding enclosure, it is critically helpful to evaluate the EMI between different circuit modules inside the shielding enclosure. To reach this aim, the Rayleigh-Carson Reciprocity theorem is referred, in which the original EM coupling problem is decomposed into the “forward problem” and “reverse problem.” A Huygens box enclosing the victim circuit module is built and the EM fields on the box are obtained using the reconstructed dipoles in both problems. Then the EMI can be calculated accordingly. Therefore, the novelty and merits of the proposed approach are threefold: 1) the physically-based equivalent dipole model considers the interactions between the radiation sources and the surrounding objects, leading to the accurate prediction of radiated emissions both outside and inside the enclosure; 2) due to the utilization of the NGF, there is no approximation involved in the solution of the dipole’s radiation, thus improving the calculation precision; and 3) the near-field coupling between multiple electronic circuit modules inside the shielding enclosure can be identified precisely, which is useful for diagnostics of radiation sources. The effectiveness of this algorithm is verified by representative numerical examples. [ABSTRACT FROM AUTHOR]

A numerical scheme, which hybridizes the element-level dual-field time-domain finite-element domain decomposition method (ELDDM) and the time-domain boundary integral (TDBI) method to accurately and efficiently analyze open-region transient electromagnetic scattering problems, is proposed. Element-level decomposition decouples Maxwell equations on a discretization element from those on its neighboring elements using equivalent currents defined on their faces. For any element inside the computation domain, the equivalent currents are obtained from fields in the neighboring elements. For any element on the boundary of the computation domain, the equivalent currents are obtained using the fields generated by TDBI. To generate these fields, TDBI “radiates” equivalent currents on a Huygens surface enclosing the scatterer. This approach when combined with a leapfrog-type time updates results in a fully explicit numerical scheme that allows ELDDM and TDBI to use different time steps. Numerical results that demonstrate the applicability of the proposed method to concave and disconnected scatterers are presented. [ABSTRACT FROM AUTHOR]

The interior resonance problem of time domain integral equations (TDIEs) formulated to analyze acoustic field interactions on penetrable objects is investigated. Two types of TDIEs are considered: The first equation, which is termed the time domain potential integral equation (TDPIE), suffers from the interior resonance problem, i.e., its solution is replete with spurious modes that are excited at the resonance frequencies of the acoustic cavity in the shape of the scatterer. Numerical experiments demonstrate that, unlike the frequency-domain integral equations, the amplitude of these modes in the time domain could be suppressed to a level that does not significantly affect the solution. This is achieved by increasing the numerical solution accuracy through the use of a higher-order discretization in space and the band limited approximate prolate spheroidal wave function with high interpolation accuracy as basis function in time. The second equation is obtained by linearly combining TDPIE with its normal derivative. The solution of this equation, which is termed the time domain combined potential integral equation (TDCPIE), does not involve any spurious interior resonance modes but it is not as accurate as the TDPIE solution at non-resonance frequencies. In addition, TDCPIE's discretization calls for treatment of hypersingular integrals. [ABSTRACT FROM AUTHOR]

In an electrostatic simulation, an equipotential condition with an undefined/floating potential value has to be enforced on the surface of an isolated conductor. If this conductor is charged, a nonzero charge condition is also required. While implementation of these conditions using a traditional finite element method (FEM) is not straightforward, they can be easily discretized and incorporated within a discontinuous Galerkin (DG) method. However, DG discretization results in a larger number of unknowns as compared to FEM. In this work, a hybridizable DG (HDG) method is proposed to alleviate this problem. Floating potential boundary conditions, possibly with different charge values, are introduced on surfaces of each isolated conductor and are weakly enforced in the global problem of HDG. The unknowns of the global HDG problem are those only associated with the nodes on the mesh skeleton and their number is much smaller than the total number of unknowns required by DG. Numerical examples show that the proposed method is as accurate as DG while it improves the computational efficiency significantly. [ABSTRACT FROM AUTHOR]