BACKGROUND AND PURPOSE Polyglycolic/polylactic acid (PGLA) addition to bare platinum coils is intended to reduce the reopening rate of coiled intracranial aneurysms. Nexus coils are standard complex platinum coils with interwoven PGLA microfilament threads. We present the clinical results of 101 intracranial aneurysms treated with Nexus coils. MATERIALS AND METHODS Results of coiling of 101 a...

Numerical solutions of the Helmholtz equation and the one-way Helmholtz equation are compared in the weak range dependence limit, where the overall range distance is increased while the range dependence is weakened. It is observed that the difference between the solutions of these two equations persists in this limit. The one-way Helmholtz equation involves a square root operator and it can be ...

An efficient finite volume approach has been used to develop a three dimensional Helmholtz acoustic solver for complex geometries. This acoustic solver was utilized to obtain characteristic mode shapes and frequencies of a baffled combustion chamber. An experimental setup, including stationary and moving sensors, has also been used to measure these quantities for the same model combustion chamb...

BACKGROUND AND PURPOSE In the treatment of cerebral aneurysms, platinum coils often fail to elicit a fibrotic response. We tested the hypothesis that a new, collagen-based endovascular coil would improve angiographic and histologic outcomes as compared with those achieved with platinum coils in a rabbit model of saccular aneurysms. METHODS Elastase-induced aneurysms were created in 12 New Zea...

The layout of the major components of the BPX poloidal field (PF) system is shown in Fig. 5.1. External to the toroidal field (TF) magnet and assembly are the seven updown symmetric pairs of primary PF-producing coils. These are called the external PF coils. They are labeled in pairs, with PFlU being the inner (small major radius) PF coil closest to and above the midplane and PFZU-PF7U proceedi...

1 Polar Biological Oceanography, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany, Centre for Natural History (CeNak), Zoological Museum, University of Hamburg, Hamburg, Germany, Wageningen Marine Research, Den Helder, Netherlands, 4 Ecological Chemistry, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany, C...

Dedicated and specialized radiofrequency coils are critical for high quality musculoskeletal magnetic resonance imaging (MRI). Dedicated coils improve the signal to noise ratio, allowing for faster or higher resolution examinations. Transmit-receive coils can reduce heating at high field strength. Finally, novel radiofrequency coils can be used for assessment of tissue biochemistry, as seen wit...

The W-S (Wake-Sleep) algorithm is a simple learning rule for the models with hidden variables. It is shown that this algorithm can be applied to a factor analysis model which is a linear version of the Helmholtz machine. But even for a factor analysis model, the general convergence is not proved theoretically. In this article, we describe the geometrical understanding of the W-S algorithm in co...

Multilayer architectures such as those used in Bayesian belief networks and Helmholtz machines provide a powerful framework for representing and learning higher order statistical relations among inputs. Because exact probability calculations with these models are often intractable, there is much interest in finding approximate algorithms. We present an algorithm that efficiently discovers highe...