Search results for "valve"

Transvalvular enteroscopy using a mother-baby endoscope system: a new approach to the distal ileum.

1997

In the past decade various endoscopes have been developed to examine the small bowel, with two principal procedures established: sonde-type enteroscopy and push-type enteroscopy. The main indication is gastrointestinal bleeding of obscure origin. Push-type enteroscopy has proved itselfto be useful for the investigation ofdiseases of the small intestine. 1 The mean instrumental insertion length published by different working groups varied between 50 and 90 cm past the ligament of Trei tzfl 2 The small bowel examination area is limited to the jejunum. The alternative method is sonde-type enteroscopy that allows an insertion length of 140 (30 to 200) cm. 3, 4 Disadvantages of this type of ente…

Trace elemental alterations of bivalve shells following transgenerational exposure to ocean acidification: Implications for geographical traceability…

2020

Trace elements of bivalve shells can potentially record the physical and chemical properties of the ambient seawater during shell formation, thereby providing valuable information on environmental conditions and provenance of the bivalves. In an acidifying ocean, whether and how seawater acidification affects the trace elemental composition of bivalve shells is largely unknown. Here, we investigated the transgenerational effects of OA projected for the end of the 21st century on the incorporation of trace elements into shells of the Manila clam, Ruditapes philippinarum. Neither seawater pH nor transgenerational exposure affected the Mg and Sr composition of the shells. Compared with clams g…

Environmental and biological factors influencing trace elemental and microstructural properties of Arctica islandica shells

2018

Long-term and high-resolution environmental proxy data are crucial to contextualize current climate change. The extremely long-lived bivalve, Arctica islandica, , is one of the most widely used paleoclimate archives of the northern Atlantic because of its fine temporal resolution. However, the interpretation of environmental histories from microstructures and elemental impurities of A. islandica, shells is still a challenge. Vital effects (metabolic rate, ontogenetic age, and growth rate) can modify the way in which physiochemical changes of the ambient environment are recorded by the shells. To quantify the degree to which microstructural properties and element incorporation into A. island…

Alterations in the Microstructure of the Anterior Mitral Valve Leaflet Under Physiological Stress

2012

An improved understanding of mitral valve (MV) function remains an important goal for determining mechanisms underlying valve disease and for developing novel therapies. Critical to heart valve tissue homeostasis is the valvular interstitial cells (VICs), which reside in the interstitium and maintain the extracellular matrix (ECM) through both protein synthesis and enzymatic degradation [1]. There is scant quantitative experimental data on the alterations of the MV fiber network reorganization as a function of load, which is critical for implementation of computational strategies that attempt to link this meso-micro scale phenomenon. The observed large scale deformations experienced by VICs…

Non-syndromic Mitral Valve Dysplasia Mutation Changes the Force Resilience and Interaction of Human Filamin A

2018

International audience; Filamin A (FLNa), expressed in endocardial endothelia during fetal valve morphogenesis, is key in cardiac development. Missense mutations in FLNa cause non-syndromic mitral valve dysplasia (FLNA-MVD). Here, we aimed to reveal the currently unknown underlying molecular mechanism behind FLNA-MVD caused by the FLNa P637Q mutation. The solved crystal structure of the FLNa3-5 P637Q revealed that this mutation causes only minor structural changes close to mutation site. These changes were observed to significantly affect FLNa's ability to transmit cellular force and to interact with its binding partner. The performed steered molecular dynamics simulations showed that signi…

Modified seromuscular tube: serosa lined bowel wall imbrication as a continent outlet for continent cutaneous urinary diversion.

1999

Purpose: We created a simplified modification of the seromuscular tube technique for continent cutaneous urinary diversion. Materials and Methods: We applied a simplified modification of our seromuscular tube technique in 1 woman and 2 men with a mean age of 53 years in whom outlet failure developed after continent cutaneous urinary diversion, and in whom adiposity and postoperative adhesions rendered revision difficult. We constructed a continent outlet conduit by imbricating the whole bowel wall and suturing it into a tube. Results: At a followup of 4 to 13 months (mean 7) all 3 patients are completely continent without leakage. Catheterization is performed at 3 to 5-hour intervals (mean …

Intussuscepted ileal flap valve for revisional surgery.

2005

Implementation of multicommutation principle with flow-through multioptosensors

2005

Abstract For the first time, the combination of multicommutation concept with flow-through multioptosensors is exploited and a biparameter multicommutated UV sensor is developed. A very easy-operated and automated sensing device is proposed here and demonstrated to be useful in the routine analysis by applying it to the determination of two widely used pharmaceuticals chosen as model analytes: salicylamide and caffeine. The particulated solid phase used performs two functions: (a) states selectivity conditions by itself in the flow cell and (b) provides appropriate separation of the analytes in the on-line precolumn, thus making possible the sequential arrival of the analytes to the detecti…

Modeling of Magnetoresistive-Based Electrical Current Sensors: A Technological Approach

2007

The utilization of modeling tools can, in many cases, help us in the design and final prototyping of any sort of sensors. In this paper, we describe a finite-element method (FEM) model applied to a hybrid technology involving a full Wheatstone bridge spin-valve-based electrical current sensor. After validating the model against experimental results, we focus our studies on geometrical aspects of the sensor configuration, in order to detect possible deviations that may have occurred during the fabrication process. In this regard, the characteristics of the behavior of the sensor depending on lateral displacements and inclination are included. Moreover, the frequency response of the sensor is…

Electrical ammeter based on spin-valve sensor.

2012

The present work shows an electrical ammeter for laboratory purpose based on a magnetoresistive (MR) spin-valve (SV) sensor. The proposed ammeter measures a 10 A maximum current and offers a maximum frequency response between 150 and 800 kHz depending on the electronics whole gain. These features are due to the use of a new generation MR-SV current sensor and a conditioning electronics that compensates in frequency and temperature the sensor response. With little adjustments in the electronics and changing the position of the sensor with respect to current carrying conductor, the designed instrument is able to measure higher current levels. The work shows the proposed ammeter with its diffe…