Proximal Contraction Research Articles

561 What Is the Clinical Significance of EGJ Outflow Obstruction? Evaluation of 60 Patients at a Tertiary Referral Center

G A A b st ra ct s swallowing. Methods: 10 healthy subjects (4 males, mean age 28, range 21-47) with simultaneous HRIM (36 sensors spaced I cm for pressure and 18 impedance segments at 2 cm intervals) and videofluoroscopy were studied. HRIM data from each of 4 swallows (5-ml Varibar thin liquid) in each subject were analyzed using a customized MATLAB program. An esophageal impedance and pressure topography (EIPT) plot (Figure) was created on which six landmarks (5 red dashed time lines and midline of the crural diaphragm) were identified: a) swallow, i.e., relaxation of the upper esophageal sphincter, b) onset of proximal contraction, c) mid transition zone, d) the contraction deceleration point (CDP), e) end of bolus transit or 12 s after ‘a'. The nadir impedance (blue curve) is also tracked for the duration of bolus transit. Intrabolus pressure was calculated during each phase as the mean pressures at the nadir impedance location for the duration of the phase. This was referenced to gastric pressure to provide an assessment of the EGPG during bolus transit. EGPG was compared amongst the phases of swallowing and between upright and supine measurements. Results: Mean (range) EGPG values during the 4 phases are summarized in the Table (2 swallows supine; 2 upright). The mean EGPG varied consistently during the 4 phases with negative pressures during accommodation, equalization with gastric pressure during compartmentalization, development of a positive EGPG during the stripping phase, and significantly increased EGPG during ampullary emptying. Pressures during each phase were greater in the supine than in the upright position. Conclusions: IBP during esophageal bolus transit varies based on functional phases of the swallow, each with distinct mechanistic implications. IBP during phase I and II would be modulated by deglutitive inhibition and mechanical properties of the esophageal wall. In contrast, measurements during phase III will be affected by peristaltic integrity and esophagogastric junction (EGJ) outflow obstruction whereas phase IV may be altered by anatomical and mechanical properties of the EGJ. Comparison of mean (range) EGPG during each phase of bolus transit (I-bolus accommodation, IIcompartmentalization, III-stripping and IV-ampullary emptying) among 10 subjects calculated using the esophageal pressure at nadir impedance locations.

Best proximity point results for modified Suzuki α-ψ-proximal contractions

Abstract In this paper, we introduce a modified Suzuki α-ψ-proximal contraction. Then we establish certain best proximity point theorems for such proximal contractions in metric spaces. As an application, we deduce best proximity and fixed point results in partially ordered metric spaces. The results presented generalize and improve various known results from best proximity and fixed point theory. Moreover, some examples are given to illustrate the usability of the obtained results. MSC:46N40, 47H10, 54H25, 46T99.

Some Properties of Distances and Best Proximity Points of Cyclic Proximal Contractions in Metric Spaces

This paper presents some results concerning the properties of distances and existence and uniqueness of best proximity points ofp-cyclic proximal, weak proximal contractions, and some of their generalizations for the non-self-mappingT:⋃i∈p-Ai→⋃i∈p-Bi (p≥2), whereAiandBi,∀i∈p-={1,2,…,p}, are nonempty subsets ofXwhich satisfyTAi⊆Bi,∀i∈p-, such that(X,d)is a metric space. The boundedness and the convergence of the sequences of distances in the domains and in their respective image sets of the cyclic proximal and weak cyclic proximal non-self-mapping, and of some of their generalizations are investigated. The existence and uniqueness of the best proximity points and the properties of convergence of the iterates to such points are also addressed.

On Best Proximity Point Theorems without Ordering

Recently, Basha (2013) addressed a problem that amalgamates approximation and optimization in the setting of a partially ordered set that is endowed with a metric. He assumed that ifAandBare nonvoid subsets of a partially ordered set that is equipped with a metric andSis a non-self-mapping fromAtoB, then the mappingShas an optimal approximate solution, called a best proximity point of the mappingS, to the operator equationSx=x, whenSis a continuous, proximally monotone, ordered proximal contraction. In this note, we are going to obtain his results by omitting ordering, proximal monotonicity, and ordered proximal contraction onS.

Best Proximity Point Results inG-Metric Spaces

G-metric spaces proved to be a rich source for fixed point theory; however, the best proximity point problem has not been considered in such spaces. The aim of this paper is to introduce certain new classes of proximal contraction mappings and establish the best proximity point theorems for such kind of mappings inG-metric spaces. As a consequence of these results, we deduce certain new best proximity and fixed point results. Moreover, we present an example to illustrate the usability of the obtained results.

Best proximity points for generalized proximal weak contractions in partially ordered metric spaces

In this paper, we prove the existence and uniqueness of best proximity point for mappings satisfying generalized proximal weak contraction in a complete ordered metric spaces. Further, our result provides an extension of a result due to Stojan Radenovic and Zoran Kadelburg to the case of non-self-mappings.

Best proximity point results for MK-proximal contractions on ordered sets

We discuss the existence and uniqueness of solutions to the minimization problem \({{\rm min}_{x \epsilon A} d(x, Tx)}\), where A, B are nonempty subsets of a partially ordered set X endowed with a metric d, and \({T : A \to B}\) is a non-self-mapping satisfying a proximal contraction of Meir–Keeler type (MK-proximal contraction). An iterative algorithm is also provided to approximate the optimal solution. As particular cases of our obtained results, various fixed point theorems on a metric space endowed with a partial order are deduced.

Best proximity points for Geraghty’s proximal contraction mappings

Abstract In this paper, we generalized the notion of proximal contractions of the first and second kinds by using Geraghty’s theorem and establish best proximity point theorems for proximal contractions. Our results improve and extend the recent results of Sadiq Basha and some others. MSC:47H09, 47H10.

Nitric oxide regulates polarity of guinea pig distal colon pellet propagation and circular muscle motor response

Peristaltic reflex does not fully explain the polarity of peristalsis. In the distal colon, we propose that the balance of circular muscle contraction proximal and distal to the pellet is a local reflex that predicts polarity of peristalsis. Guinea pig distal colon segments were harvested, and fecal pellet transit was measured. Photographs of fecal pellet propagation were taken, colonic radius proximal and distal to the moving pellet was measured, and the ratio of radius proximal to pellet to radius distal to pellet was measured. Isometric transducers were attached 1 cm proximal and distal to a fixed intraluminal balloon, and circular muscle (CM) response to balloon distension was recorded. N (G)-Nitro-L-arginine methyl ester hydrochloride (L-NAME) was used to elicit an effect in experimental preparations and compared to controls. Fecal pellet transit was delayed after L-NAME treatment (163 ± 23.9 vs. 41.5 ± 1.9 s in control, n = 6, p < 0.001). Photo-analysis revealed a ratio of proximal/distal colonic radius in control colon to be 0.72 ± 0.02 (n = 17) and in L-NAME treated colon 1.0 ± 0.02 (n = 10, p < 0.01). The dominant CM response pattern was a large contraction proximal to the inflated balloon and a smaller contraction distal to the balloon. In the presence of L-NAME, distal contraction was larger than the proximal contraction in 66% of the experiments. Pellet propulsion in the guinea pig's distal colon depends on nitric oxide to provide appropriate balance of force between proximal and distal contraction, resulting in pellet propagation toward the anus. CM contracts both proximal and distal to the pellet, and the polarity of pellet progression depends on the balance of the two forces.

Tu1782 Weak Peristalsis With Large Breaks Is Associated With Higher Acid Exposure and Delayed Reflux Clearance in the Supine Position in GERD Patients

INTRODUCTION It has been demonstrated that among esophageal motor abnormalities, impaired peristalsis of the esophageal body may account for delayed bolus transit and impaired esophageal refl ux clearance in patients with complicated gastroesophageal refl ux disease (GERD) ( 1,2 ). In particular, several studies have shown that ineffective esophageal motility (IEM), defi ned as the presence of peristaltic waves at the distal esophagus with amplitude < 30 mm Hg and / or nontransmitted proximal contractions, is frequently observed in GERD patients; however, the functional relevance remains controversial ( 3 ). In GERD patients, increasing degrees of esophageal mucosal damage have been reported either to cause, or be the result of, severe worsening of esophageal function ( 4,5 ). Nevertheless, even if IEM has been associated with prolonged acid exposure time (AET) ( 6 ), it has been demonstrated that in GERD patients, only severe, but not mild IEM, is associated with prolonged clearance and AET, particularly when in the supine position ( 7 ). Th e recent development of high-resolution manometry (HRM) has led to an improvement of our knowledge regarding esophageal motility and is considered the gold standard in the study of esophageal motor disorders ( 8 ). Indeed, HRM combined with multichannel impedance (HRM-MI) monitoring allows simultaneous recording and analysis of the esophageal motility and of the bolus transit. Fox et al. ( 9 )demonstrated, using HRM coupled with videofl uoroscopy, that HRM pressure topography plots predict bolus transit more accurately than conventional manometry. Moreover, these authors reported that, as a consequence of the increased spatial resolution, HRM is also able to detect segmental breaks of the esophageal peristalsis that would otherwise have been missed with conventional manometry. More recently, Bulsiewicz et al. ( 10 ) showed in healthy subjects and in patients with nonobstructive dysphagia that peristaltic breaks of < 2 cm in the 20 mm Hg or < 3 cm in the 30 mm Hg isobaric contour are associated with complete bolus clearance, whereas larger breaks predict delayed bolus clearance. Moreover, it has been proposed that weak peristalsis could be defi ned Weak Peristalsis With Large Breaks Is Associated With Higher Acid Exposure and Delayed Refl ux Clearance in the Supine Position in GERD Patients

Best proximity point theorems for rational proximal contractions

Abstract We provide sufficient conditions which warrant the existence and uniqueness of the best proximity point for two new types of contractions in the setting of metric spaces. The presented results extend, generalize and improve some known results from best proximity point theory and fixed-point theory. We also give some examples to illustrate and validate our definitions and results. MSC:41A65, 46B20, 47H10.

The Existence Theorems of an Optimal Approximate Solution for Generalized Proximal Contraction Mappings

Recently, Basha (2011) established the best proximity point theorems for proximal contractions of the first and second kinds which are extension of Banach's contraction principle in the case of non-self-mappings. The aim of this paper is to extend and generalize the notions of proximal contractions of the first and second kinds which are more general than the notion of self-contractions, establish the existence of an optimal approximate solution theorems for these non-self-mappings, and also give examples to validate our main results.

Best Proximity Points for Some Classes of Proximal Contractions

Given a self-mapping and a non-self-mapping , the aim of this work is to provide sufficient conditions for the existence of a unique point , calledg-best proximity point, which satisfies . In so doing, we provide a useful answer for the resolution of the nonlinear programming problem of globally minimizing the real valued function , thereby getting an optimal approximate solution to the equation . An iterative algorithm is also presented to compute a solution of such problems. Our results generalize a result due to Rhoades (2001) and hence such results provide an extension of Banach's contraction principle to the case of non-self-mappings.

Best Proximity Point Results for Modified --Proximal Rational Contractions

We first introduce certain new concepts of --proximal admissible and ---rational proximal contractions of the first and second kinds. Then we establish certain best proximity point theorems for such rational proximal contractions in metric spaces. As an application, we deduce best proximity and fixed point results in partially ordered metric spaces. The presented results generalize and improve various known results from best proximity point theory. Several interesting consequences of our obtained results are presented in the form of new fixed point theorems which contain famous Banach's contraction principle and some of its generalizations as special cases. Moreover, some examples are given to illustrate the usability of the obtained results.

Best proximity point theorems: unriddling a special nonlinear programming problem

This paper addresses the non-linear programming problem of globally minimizing the real valued function x⟶d(x,Sx) where S is a generalized proximal contraction in the setting of a metric space. Eventually, one can obtain optimal approximate solutions to some fixed-point equations in the event that they have no solution.

Best proximity point theorems: exposition of a significant non-linear programming problem

The primary goal of this work is to address the non-linear programming problem of globally minimizing the real valued function x ? d(x, Tx) where T is presumed to be a non-self mapping that is a generalized proximal contraction in the setting of a metric space. Indeed, an iterative algorithm is presented to determine a solution of the preceding non-linear programming problem that focuses on global optimization. As a sequel, one can compute optimal approximate solutions to some fixed point equations and optimal solutions to some unconstrained non-linear programming problems.

Global optimization in metric spaces with partial orders

The main objective of this article is to resolve an optimization problem in the setting of a metric space that is endowed with a partial order. In fact, given non-empty subsets A and B of a metric space that is equipped with a partial order, and a non-self mapping S: A → B, this article explores the existence of an optimal approximate solution, known as a best proximity point of the mapping S, to the equation Sx = x, where S is a proximally increasing, ordered proximal contraction. This article exhibits an algorithm for determining such an optimal approximate solution. Moreover, the result elicited in this article subsumes a fixed point theorem, due to Nieto and Rodriguez-Lopez, in the setting of a metric space with a partial order.

Best proximity point theorems on partially ordered sets

The main purpose of this article is to address a problem that amalgamates approximation and optimization in the setting of a partially ordered set that is endowed with a metric. Indeed, if A and B are non-void subsets of a partially ordered set that is equipped with a metric, and S is a non-self mapping from A to B, this paper scrutinizes the existence of an optimal approximate solution, called a best proximity point of the mapping S, to the operator equation Sx = x where S is a continuous, proximally monotone, ordered proximal contraction. Further, this paper manifests an iterative algorithm for discovering such an optimal approximate solution. As a special case of the result obtained in this article, an interesting fixed point theorem on partially ordered sets is deduced.

Best proximity point theorems for generalized proximal contractions

Best proximity point theorems unravel the techniques for determining an optimal approximate solution, designated as a best proximity point, to the equation Tx = x which is likely to have no solution when T is a non-self mapping. This article presents best proximity point theorems for new classes of non-self mappings, known as generalized proximal contractions, in the setting of metric spaces. Further, the famous Banach's contraction principle and some of its generalizations and variants are realizable as special cases of the aforesaid best proximity point theorems.

Normative values of the esophageal manometry and its influential factors in the healthy subjects: a multiple center study in China

Objective To establish normative values of esophageal manometry in different age groups and standard test method.Methods The values of esophageal manometry were tested in healthy subjects of 3 different age groups (Group Ⅰ: 18-39 years,Group Ⅱ: 40-59 years,Group Ⅲ:≥60 years) with pneumohydraulic capillary perfusion system.The repeatability and stability of this method in lower esophageal sphincter (LES) testing were observed. Results There were no significant differences of LES length (LESL),LES pressure (LESP) at the end of expiration,average LESP,residual pressure of LES and LES relaxation rate (LESRR) in three groups (P＞0.05).The LESP at the end of inspiration in Group Ⅰ (28.98± 1.11 ) mm Hg was significantly lower than that of Group Ⅲ (34.35±1.96) mm Hg (P＜0.05).Trandiaphragmatic pressure (Pdi) in Group Ⅰ (9.55±0.62) mm Hg was significantly lower than that of Group Ⅱ (13.05±0.76) mm Hg (P＜0.05).There were no significant differences in contraction amplitude and duration of proximal and distant esophagus in 3 groups (P＞0.05).UES pressure (UESP) of Group Ⅲ was significantly lower than that of Group Ⅰ and Ⅱ (P＜0.05).As for repeatability,the second recording of LESP in Group Ⅰ and Ⅱ were significantly higher than first recording (P＜0.05).Amplitude of distant esophageal peristaltic contraction (DEPC) of female was significantly higher than of male (P＜0.05).However,there was no significant difference in amplitude of proximal esophageal peristaltic contraction (PEPC)between femal and male (P＞0.05).Conclusions The normative values of esophageal manometry in different age groups have been obtained.The dynamic parameters of LES do not change with age.Between age 40 to 59 years old,the contraction of esophageal body is strongest.UESP decreases significantly in old people.If the subjects have enough time to adapt before test,it will help to get accurate and reliable dynamic parameters of LES. Key words: Esophageal sphincter, lower; Age factors; Esophageogastric junction; manometry; Peristalsis