118 research outputs found

    The effect of nitric oxide on the pressure of the acutely obstructed ureter

    Get PDF
    Acute ureteral obstruction leads to changes in pressure inside the ureter, interrupting ureter function. The aim of our study is to explore the relationship between nitric oxide (NO) concentration and pressure in the ureter and to observe the effects of nitric oxide on the revival of renal function. We created the animal models by embedding balloons in the lower ureters of anesthetized dogs and expanding them to simulate acute ureteral obstruction. First, the test animals were pre-treated intravenously with different doses of L-NAME (non-selective nitric oxide synthase inhibitor) to inhibit nitric oxide synthase (NOS), and 10 min later, each subject was administered an intravenous dose of isoproterenol (10 Όg/kg). We measured ureter pressure (UP), total and peak concentrations of NO (using an NO monitor, model inNO-T) in ureteral urine, and the volume of the urine (UFV) leaking from the balloon edge. After a certain amount of time had elapsed, it became clear that the dose of L-NAME was inversely related to the total and peak concentrations of NO, the rate of change in UP, and the volume of urine produced. We conclude that L-NAME prevents the NOS from inhibiting the release of NO, then inhibits the effect of isoproterenol reducing the pressure of the acute obstructive ureter. Inversely, we think that NO can reduce the pressure of the acute obstructive ureter and make the obstructive ureter recanalization. And when more the concentration of nitric oxide, the more the pressure will be reduced, and more urine will be collected

    The GEYSERS optical testbed: a platform for the integration, validation and demonstration of cloud-based infrastructure services

    Get PDF
    The recent evolution of cloud services is leading to a new service transformation paradigm to accommodate network infrastructures in a cost-scalable way. In this transformation, the network constitutes the key to efficiently connect users to services and applications. In this paper we describe the deployment, validation and demonstration of the optical integrated testbed for the “GEneralized architecture for dYnamic infrastructure SERviceS” (GEYSERS) project to accommodate such cloud based Infrastructure Services. The GEYSERS testbed is composed of a set of local physical testbeds allocated in the facilities of the GEYSERS partners. It is built up based on the requirements specification, architecture definition and per-layer development that constitutes the whole GEYSERS ecosystem, and validates the procedures on the GEYSERS prototypes. The testbed includes optical devices (layer 1), switches (layer 2), and IT resources deployed in different local testbeds provided by the project partners and interconnected among them to compose the whole testbed layout. The main goal of the GEYSERS testbed is twofold. On one hand, it aims at providing a validation ground for the architecture, concepts and business models proposed by GEYSERS, sustained by two main paradigms: Infrastructure as a Service (IaaS) and the coupled provisioning of optical network and IT resources. On the other hand, it is used as a demonstration platform for testing the software prototypes within the project and to demonstrate to the research and business community the project approach and solutions. In this work, we discuss our experience in the deployment of the testbed and share the results and insights learned from our trials in the process. Additionally, the paper highlights the most relevant experiments carried out in the testbed, aimed at the validation of the overall GEYSERS architecture

    Facilitating Organisational Fluidity with Computational Social Matching

    Get PDF
    Striving to operate in increasingly dynamic environments, organisations can be seen as fluid and communicative entities where traditional boundaries fade away and collaborations emerge ad hoc. To enhance fluidity, we conceptualise computational social matching as a research area investigating how to digitally support the development of mutually suitable compositions of collaborative ties in organisations. In practice, it refers to the use of data analytics and digital methods to identify features of individuals and the structures of existing social networks and to offer automated recommendations for matching actors. In this chapter, we outline an interdisciplinary theoretical space that provides perspectives on how interaction can be practically enhanced by computational social matching, both on the societal and organisational levels. We derive and describe three strategies for professional social matching: social exploration, network theory-based recommendations, and machine learning-based recommendations.Striving to operate in increasingly dynamic environments, organisations can be seen as fluid and communicative entities where traditional boundaries fade away and collaborations emerge ad hoc. To enhance fluidity, we conceptualise computational social matching as a research area investigating how to digitally support the development of mutually suitable compositions of collaborative ties in organisations. In practice, it refers to the use of data analytics and digital methods to identify features of individuals and the structures of existing social networks and to offer automated recommendations for matching actors. In this chapter, we outline an interdisciplinary theoretical space that provides perspectives on how interaction can be practically enhanced by computational social matching, both on the societal and organisational levels. We derive and describe three strategies for professional social matching: social exploration, network theory-based recommendations, and machine learning-based recommendations.Peer reviewe

    Pressure tension, and force of closure of the human lower esophageal sphincter and esophagus.

    Get PDF
    The mechanical characteristics of the circular muscle of the human lower esophageal sphincter and esophagus were studied in subjects with competent and incompetent sphincters. Pressure-diameter curves were constructed by producing various degrees of circumferential stretch with pressure-measuring probes of increasing diameter. The circumferential membrane tension (force of closure) and the circumferential stress (muscle tension) of the circular muscle layer were also calculated from these data. The pressure-diameter curves of competent and incompetent sphincters were different in magnitude and shape. Incompetent sphincters had lower pressures at all diameters, with pressure gradually increasing with larger probe diameter. In contrast for competent sphincters the pressure was highest near closure, with an initial decline and then an increase in pressure with increasing probe diameter. Both shape and magnitude of pressure-diameter curves of competent and incompetent sphincters were interchangeable when manipulated by pharmacologic agents. Urecholine increased the pressures and changed the incompetent pressure-diameter curve to the levels of the competent sphincter; conversely. Pro-Banthine decreased pressures and changed the shape of the competent pressure-diameter curve to the levels of the incompetent sphincter. Force of closure and circular muscle tension curves of competent and incompetent sphincters were similar in shape but were higher at all diameters for competent sphincters. Force of closure and circular muscle tension increased with larger probe diameter. However, the diameter of optimal tension development was larger than the largest probe used and certainly far from closure. Fundoplication increased the magnitude and changed the shape of the incompetent pressure-diameter curve to one similar to a competent curve. This pressure change was associated with an increase in the force of closure, suggesting that fundopliation modified the length-force of closure characteristics of the incompetent spincter
    • 

    corecore