Filter-Base Mounting

2012 ◽  
Author(s):  
Keyword(s):  
Filter Base

Asymptotic centres of filters on uniformly rotund spaces

1976 ◽  
Vol 15 (1) ◽  
pp. 87-96
Author(s):  
John Staples
Keyword(s):  
Banach Space ◽  
Fixed Point ◽  
Metric Space ◽  
Fixed Point Theorems ◽  
Convex Banach Space ◽  
Bounded Sequence ◽  
Uniform Convexity ◽  
Uniformly Convex Banach Space ◽  
Uniformly Convex ◽  
Filter Base

The notion of asymptotic centre of a bounded sequence of points in a uniformly convex Banach space was introduced by Edelstein in order to prove, in a quasi-constructive way, fixed point theorems for nonexpansive and similar maps.Similar theorems have also been proved by, for example, adding a compactness hypothesis to the restrictions on the domain of the maps. In such proofs, which are generally less constructive, it may be possible to weaken the uniform convexity hypothesis.In this paper Edelstein's technique is extended by defining a notion of asymptotic centre for an arbitrary set of nonempty bounded subsets of a metric space. It is shown that when the metric space is uniformly rotund and complete, and when the set of bounded subsets is a filter base, this filter base has a unique asymptotic centre. This fact is used to derive, in a uniform way, several fixed point theorems for nonexpansive and similar maps, both single-valued and many-valued.Though related to known results, each of the fixed point theorems proved is either stronger than the corresponding known result, or has a compactness hypothesis replaced by the assumption of uniform convexity.

Design of the acousto-optic tunable filter base on the rotatory property of TeO<sub>2</sub>

2011 ◽  
Vol 41 (8) ◽  
pp. 917-923
Author(s):  
Feng ZHENG ◽  
Yong TAN ◽  
HongXing CAI ◽  
Yu REN ◽  
XiHe ZHANG
Keyword(s):  
Tunable Filter ◽  
Filter Base

Assessment of Apparent Vena Caval Penetration by the Greenfield Filter

1998 ◽  
Vol 5 (3) ◽  
pp. 251-258 ◽  
Author(s):  
Mary C. Proctor ◽  
Lazar J. Greenfield ◽  
Kyung J. Cho ◽  
Mohammed M. Moursi ◽  
Eric A. James
Keyword(s):  
Computed Tomography ◽  
Vena Cava ◽  
Scar Tissue ◽  
Radial Force ◽  
Base Diameter ◽  
Greenfield Filter ◽  
Filter Base ◽  
Venae Cavae ◽  
Adjacent Structures ◽  
Tissue Histology

Purpose: To examine and elucidate the mechanisms for apparent “penetration” by Greenfield vena caval filters. Methods: Two filters were placed in the inferior venae cavae (IVC) of four immature sheep and followed with cavography for 1 year. Two animals underwent computed tomography (CT) and laparoscopic examination. At necropsy, the vena cava and adjacent structures of all four animals were examined grossly and histologically. Results: Based upon cavography and CT imaging, all filters appeared to penetrate the vena cava at 12 months. However, at laparoscopy, no hooks or limbs were exposed, and the pericaval tissues remained intact; each hook or limb was within the adventitia or encapsulated in scar tissue. Histology of the tissue at the hook sites revealed remodeling of the intimal surface of the IVC and thinning of the adventitia. Conclusions: Based upon these data, we hypothesize that the vena cava gradually adapts by medial and adventitial thinning and myointimal remodeling to the radial force exerted by a filter. This process allows increase in the filter base diameter while maintaining the integrity of the cava and protecting adjacent structures.

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