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Open Architecture (open + architecture)

Distribution by Scientific Domains

Medical Sciences	40%
Chemistry	40%

Selected Abstracts

ChemInform Abstract: Three-Dimensional Zinc Phosphates with Open Architectures.

CHEMINFORM, Issue 1 2001
S. Neeraj
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Current density mapping approach for design of clinical magnetic resonance imaging magnets

CONCEPTS IN MAGNETIC RESONANCE, Issue 3 2002
Stuart Crozier
Abstract Novel current density mapping (CDM) schemes are developed for the design of new actively shielded, clinical magnetic resonance imaging (MRI) magnets. This is an extended inverse method in which the entire potential solution space for the superconductors has been considered, rather than single current density layers. The solution provides an insight into the required superconducting coil pattern for a desired magnet configuration. This information is then used as an initial set of parameters for the magnet structure, and a previously developed hybrid numerical optimization technique is used to obtain the final geometry of the magnet. The CDM scheme is applied to the design of compact symmetric, asymmetric, and open architecture 1.0,1.5 T MRI magnet systems of novel geometry and utility. A new symmetric 1.0-T system that is just 1 m in length with a full 50-cm diameter of the active, or sensitive, volume (DSV) is detailed, as well as an asymmetric system in which a 50-cm DSV begins just 14 cm from the end of the coil structure. Finally a 1.0-T open magnet system with a full 50-cm DSV is presented. These new designs provide clinically useful homogeneous regions and have appropriately restricted stray fields but, in some of the designs, the DSV is much closer to the end of the magnet system than in conventional designs. These new designs have the potential to reduce patient claustrophobia and improve physician access to patients undergoing scans. © 2002 Wiley Periodicals, Inc. Concepts in Magnetic Resonance (Magn Reson Engineering) 15: 208,215, 2002 [source]

Patent Foramen Ovale Using the Premere Device: The Results of the CLOSEUP Trial

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 4 2006
FRANZISKA BÜSCHECK M.D.
Objectives: The CLOSEUP trial was conducted to determine the safety and effectiveness of the Premere closure device in closure of patent foramen ovale (PFO). Background: PFO is a relatively common congenital condition, associated with cryptogenic stroke and migraine with aura. The Premere device is specifically designed to close PFO of variable size and length, with right and left anchor arms connected by a flexible tether. The device has an open architecture, a low profile, and a small surface area on the left atrial side which may discourage thrombus formation. Methods: Patients between 18 and 65 years of age who had a cryptogenic ischemic stroke or a transient ischemic attack and a PFO underwent percutaneous PFO closure using the Premere device. Results: Of the 73 enrolled patients, six patients had atrial anatomy not appropriate for the Premere; 27 patients received the 15 mm and 40 patients received the 20 mm device. Implantation was successful in all patients. At 6 months of follow-up, 86% of patients had no shunt that could be provoked with Valsalva as assessed during contrast echocardiography. Closure rates were better with the 20 mm versus the 15 mm device, and three patients with residual shunt had atrial septal aneurysms at baseline. One patient had transient atrial fibrillation which resolved by 3 months. There were no instances of thrombus, death, or stroke. Conclusions: These data demonstrate that the Premere device can safely and effectively close PFO. Additional studies should be undertaken to demonstrate the effectiveness of PFO closure in reducing thrombo-embolic events such as stroke. [source]

The good, the bad and the wiki: Evaluating student-generated content for collaborative learning

BRITISH JOURNAL OF EDUCATIONAL TECHNOLOGY, Issue 6 2008
Steve Wheeler
This paper explores the potential for wiki-type open architecture software to promote and support collaborative learning through the use of student-created content. It delineates some of the affordances and constraints of wiki software as an open architecture that has the potential to facilitate collaborative learning through community-focused enquiry. It seeks to promote debate in this key area of development, and highlights some recent key contributions to the developing discourse on social software in what has been termed ,the architecture of participation'. [source]

Synthons and design in metal phosphates and oxalates with open architectures

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 1 2001
C. N. R. Rao
We briefly describe the structures of open-framework metal phosphates with different dimensionalities, such as the one-dimensional linear-chain and ladder structures, two-dimensional layer structures and three-dimensional structures with channels. We demonstrate the role of the zero-dimensional four-membered ring monomer and of the one-dimensional ladder structure as the starting building units or synthons involved in the formation of the complex architectures. Thus, we show how the one-dimensional ladder structure transforms to two- and three-dimensional structures under mild conditions. The two-dimensional layer structures also transform to three-dimensional structures, while the zero-dimensional monomer transforms to layered and three-dimensional structures under ordinary reaction conditions. These transformations provide an insight into the possible pathways involved in the building up of the complex structures of metal phosphates. The isolation of amine phosphates during the hydrothermal synthesis of metal phosphates and also the facile reactions between amine phosphates and metal ions to yield a variety of open-framework materials have thrown light on the mechanism of formation and design of these structures. The existence of a hierarchy of open-framework metal oxalates and their ready formation by employing amine oxalates as intermediates provides additional support to the observations made earlier with regard to the phosphates. [source]