Search

To test whether phase analysis indices from SPECT-MPI for left ventricular mechanical dyssynchrony (LVMD) are predictors of major adverse cardiac events (MACEs) in long-standing diabetes mellitus (DM). A total of 136 DM patients with normal perfusion and left ventricular systolic functions were followed up for about two years and divided into two groups according to the presence and the absence of MACEs. Thirteen (9.5%) patients experienced MACEs during follow-up. Patients experiencing MACEs showed significantly higher phase standard deviation (PSD) and wider phase bandwidth (PBW) than those who did not. Moreover, both PSD and PBW showed significant correlations (r = 0.25 and 0.27; P

This paper proposes an easy, efficient strategy for designing broadband, wide-angle and polarization-independent diffusion metasurface for radar cross section (RCS) reduction. A dual-resonance unit cell, composed of a cross wire and cross loop (CWCL), is employed to enhance the phase bandwidth covering the 2π range. Both oblique-gradient and horizontal-gradient phase supercells are designed for illustration. The numerical results agree well with the theoretical ones. To significantly reduce backward scattering, the random combinatorial gradient metasurface (RCGM) is subsequently constructed by collecting eight supercells with randomly distributed gradient directions. The proposed metasurface features an enhanced specular RCS reduction performance and less design complexity compared to other candidates. Both simulated and measured results show that the proposed RCGM can significantly suppress RCS and exhibits broadband, wide-angle and polarization independence features.

In this paper, a novel wideband low-profile artificial magnetic conductor (AMC) surface is proposed. The ±90° reflection phase bandwidth of the proposed AMC is 4.63–7.01 GHz (41%). By loading a $12 \times 12$ AMC array below a circularly polarized (CP) slot antenna, the unidirectional CP radiation patterns are obtained. Utilizing the in-phase reflection of the AMC surface, the profile of the unidirectional slot antenna loaded with AMC reflector (Ant-AMC) can be obviously reduced compared with the slot antenna loaded with metal reflector (Ant-PEC). The −10 dB impedance bandwidth of the proposed Ant-AMC is 2.08–5.23 GHz (86.2%) and the 3-dB axial-ratio bandwidth (ARBW) is 3.48–5.45 GHz (44.1%).

In this study, investigations on sub-wavelength and multi-resonant single layer reflectarray elements have been carried out for enhanced bandwidth. Elements such as (1) parallel sub-wavelength dipoles, (2) sub-wavelength circular rings, (3) /-shaped dipole surrounded by rectangular split rings, and (4) L-shaped stub loaded square ring are analyzed by employing substrates of varied thicknesses and dielectric constants for their reflection phase performances, which is then plotted as a function of frequency. The analysis has been carried out by using unit cell approach in CST MW Studio 2017. It is interesting to note that the typical reflection phase bandwidth of these elements is in the range of 40% and 57% in Ku and X-Ku bands.

Left ventricular (LV) phase dyssynchrony parameters based on gated myocardial perfusion imaging varied among software programs. The aim of this study was to determine normal ranges and factors affecting phase parameters. Normal databases were derived from the Japanese Society of Nuclear Medicine working group (n = 69). The programs were Emory Cardiac Toolbox with SyncTool (ECTb), Quantitative Gated SPECT (QGS), Heart Function View (HFV), and cardioREPO (cREPO); parameters of phase standard deviation (PSD), 95% bandwidth, and entropy were compared with parameters with ECTb as a reference. PSD (degree) was 5.3 ± 3.3 for QGS (P