Balanced steady-state free precession (SSFP) sequences are useful in cardiac imaging because they achieve high signal efficiency and excellent blood-myocardium contrast. Spiral imaging enables the efficient acquisition of cardiac images with reduced flow and motion artifacts. Balanced SSFP has been combined with spiral imaging for real-time interactive cardiac MRI. New features of this method t...

This thesis contributes to the computer-aided design (CAD) of spiral inductors and LC resonators with spiral inductors exploiting full-wave electromagnetic (EM) analysis. The spiral inductor is widely used in radio frequency integrated circuits (RF ICs), such as low noise amplifiers (LNA) and voltage controlled oscillators (VCO). The design of spiral inductors has a direct influence on the perf...

Every sixth death in industrialized countries occurs because of cardiac arrhythmias such as ventricular tachycardia (VT) and ventricular fibrillation (VF). There is growing consensus that VT is associated with an unbroken spiral wave of electrical activation on cardiac tissue but VF with broken waves, spiral turbulence, spatiotemporal chaos and rapid, irregular activation. Thus spiral-wave acti...

The majority of astrophysics involves the study of spiral galaxies, and stars and planets within them, but how spiral arms in galaxies form and evolve is still a fundamental problem. Major progress in this field was made primarily in the 1960s, and early 1970s, but since then there has been no comprehensive update on the state of the field. In this review, we discuss the progress in theory, and...

The spiral ganglion is an essential functional component of the peripheral auditory system. Most types of hearing loss are associated with spiral ganglion cell degeneration which is irreversible due to the inner ear's lack of regenerative capacity. Recent studies revealed the existence of stem cells in the postnatal spiral ganglion, which gives rise to the hope that these cells might be useful ...

PURPOSE Evaluate spiral three-dimensional (3D) phase contrast MRI for the assessment of turbulence and velocity in stenotic flow. METHODS A-stack-of-spirals 3D phase contrast MRI sequence was evaluated in vitro against a conventional Cartesian sequence. Measurements were made in a flow phantom with a 75% stenosis. Both spiral and Cartesian imaging were performed using different scan orientati...

This paper presents the aspects related to the design and development of a tapered spiral helix antenna covering the frequency range 1.2-18GHz. It is a compact stateof-the-art circularly polarized antenna, which works over multi-octave frequency bandwidth (1.2-18 GHz).The antenna size has been reduced by 50 percent with respect to conventional spiral antenna used for same frequency band. Spiral...

We examine models in which jets are responsible for the formation of the emission-line spiral structure in IRAS 04210+0400. The kiloparsec-scale radio lobes in this active galaxy appear to be related to its extended emission-line spiral structure. The radio structure consists mainly of extended symmetrically bent, FR I-type lobes, which follow the emission-line spiral structure at their inner e...

In this article an Archimedean spiral antenna is designed and analyzed that has good operation in broadband application. By analyzing this design, the effects that different parameters have on antenna operation will be studied and ways of optimization will be found.  Influences of cavity height and number of turns to obtain good matching and gain in a frequency interval of 4 to 18 GHz will be d...