We present a formulation of mean-field approximation for layered feed-forward stochastic networks. In this formulation, one can obtain not only estimates of averages for state variables of the networks but also those of intra-layer correlations, the latter of which cannot be obtained by the conventional mean-jield approximation. Moreovel; this formulation provides a pamework to treat “condition...

Unsupervised training of deep generative models containing latent variables and performing inference remains a challenging problem for complex, high dimensional distributions. One basic approach to this problem is the so called Helmholtz machine and it involves training an auxiliary model that helps to perform approximate inference jointly with the generative model which is to be fitted to the ...

Magnetic resonance imaging (MRI) is a very powerful tool for diagnostic imaging; however, it is very seldom used for guiding interventional procedures. On the other hand, in many procedures the quality of the guiding image modality is less than perfect, and therefore, MRI can be considered as an alternative. Among these interventional procedures, the percutaneous cardiovascular procedures have ...

A review of the theory, technology, and practice of RF coils for small-animal MRI is presented that includes a brief overview of MR S/N analysis and discussions of the various coils commonly used in small-animal MR – surface coils, linear volume coils, birdcages, and their derivatives. The scope is limited to mid-range coils – coils where the product (fd) of the frequency f and the coil diamete...

Appropriately sized 0.010- and 0.018-inch complex framing coils were placed in a wide-necked silicone aneurysm replica, and their stability was evaluated at variable physiologic flow rates using video recording. After detachment, the 0.010-inch coils demonstrated instability/prolapse that was proportional to flow rate. In contrast, 0.018-inch coils held their 3D configuration regardless of flow...

BACKGROUND AND PURPOSE To assess safety and efficacy data of a new bioactive coil (Cerecyte) which is loaded with polyglycolic acid on the inside of the coil. METHODS Fifty-four patients harboring 55 aneurysms were treated with Cerecyte coils. These aneurysms were matched in localization and size with aneurysms treated with bare platinum coils. RESULTS Periprocedural complications and handl...

A general dark-soliton solution of the Helmholtz equation (with defocusing Kerr nonlinearity) that has on- and off-axis, gray and black, paraxial and Helmholtz solitons as particular solutions, is reported. Modifications to soliton transverse velocity, width, phase period, and existence conditions are derived and explained in geometrical terms. Simulations verify analytical predictions and also...

A. K. Bera, ∗ B. Lake, 2 A. T. M. N. Islam, B. Klemke, E. Faulhaber, † and J. M. Law Helmholtz Zentrum Berlin für Materialien und Energie, D-14109 Berlin, Germany Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, D-10623 Berlin, Germany Helmholtz Zentrum Berlin für Materialien und Energie, Gemeinsame Forschergruppe, D-85747 Garching, Germany Hochfeld Magnetlab D...

When the transmitting and receiving coils are equivalent with or not significantly smaller than their separation distance between the two coils, the results of numerical simulations for transfer efficiency of system show that the maximum coupling of two coils or maximum transfer efficiency occur with a certain tilt angle between two coils, which means the two coils with parallel on the same axi...

INTRODUCTION Shielded RF coils have been investigated since the earliest days of MRI, taking the form of the “Zabel coil” [1] a shielded transmission line coil, coils over ground planes, and more recently microstrip coils, particularly for use at high-fields [2]. Some authors have stated that RF shields are essential for 7T surface coils over 10 cm in diameter [3], and others have successfully ...