146,313 research outputs found
Placental Morphology of Pregnant Iraqi Women with Rheumatic Heart Disease
Background: Placental morphology and cellular arrangement can be altered in maternal diseases. Rheumatic heart disease (RHD) is a chronic heart condition that can lead to death in pregnant women. The aim of this study is to determine the histological changes of the placenta in pregnant women suffering from RHD. Methods: Placentae were collected from 10 healthy pregnant women, and 31 pregnant women with heart conditions (26 with RHD and 5 with NRHD) who had been admitted to the Baghdad Teaching Hospital. Placental tissues were fixed in 10% formal-saline and were processed for light microscopy. Measurements including the placental weight and diameter of the chorionic villi capillaries were recorded. Results: The results indicate that there are many histological changes in pregnant women with RHD such as hyalinisation, fibrosis of the chorionic villi, proliferation of trophoblastic cells, and thickening of its membrane. Additionally, expectant mothers with RHD experience a reduction in capillary diameter and thickening of the capillary walls, and decreased size and weight of their placenta when compared with the control. Conclusions: Heart diseases, especially RHD, are associated with developmental damage of the placenta in pregnant women by injuring the endothelial cells of the placentas capillaries
Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI
BACKGROUND:
Coronary revascularization guided by fractional flow reserve (FFR) is associated with better patient outcomes after the procedure than revascularization guided by angiography alone. It is unknown whether the instantaneous wave-free ratio (iFR), an alternative measure that does not require the administration of adenosine, will offer benefits similar to those of FFR.
METHODS:
We randomly assigned 2492 patients with coronary artery disease, in a 1:1 ratio, to undergo either iFR-guided or FFR-guided coronary revascularization. The primary end point was the 1-year risk of major adverse cardiac events, which were a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization. The trial was designed to show the noninferiority of iFR to FFR, with a margin of 3.4 percentage points for the difference in risk.
RESULTS:
At 1 year, the primary end point had occurred in 78 of 1148 patients (6.8%) in the iFR group and in 83 of 1182 patients (7.0%) in the FFR group (difference in risk, -0.2 percentage points; 95% confidence interval [CI], -2.3 to 1.8; P<0.001 for noninferiority; hazard ratio, 0.95; 95% CI, 0.68 to 1.33; P=0.78). The risk of each component of the primary end point and of death from cardiovascular or noncardiovascular causes did not differ significantly between the groups. The number of patients who had adverse procedural symptoms and clinical signs was significantly lower in the iFR group than in the FFR group (39 patients [3.1%] vs. 385 patients [30.8%], P<0.001), and the median procedural time was significantly shorter (40.5 minutes vs. 45.0 minutes, P=0.001).
CONCLUSIONS:
Coronary revascularization guided by iFR was noninferior to revascularization guided by FFR with respect to the risk of major adverse cardiac events at 1 year. The rate of adverse procedural signs and symptoms was lower and the procedural time was shorter with iFR than with FFR. (Funded by Philips Volcano; DEFINE-FLAIR ClinicalTrials.gov number, NCT02053038 .)info:eu-repo/semantics/publishedVersio
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A novel architecture for a reconfigurable micro machining cell
There is a growing demand for machine tools that are specifically designed for the manufacture of micro-scale components. Such machine tools are integrated into flexible micro-manufacturing systems. Design objectives for such tools include energy efficiency, small footprint and importantly flexibility, with the ability to easily reconfigure the manufacturing system in response to process requirements and product demands. Such systems find application in medical, photonics, automotive and electronic industries.
In this paper, a new architecture for a reconfigurable micro manufacturing system is presented. The proposed architecture comprises a micro manufacturing cell with the key design feature being a hexagonal-base on which three tool heads can be attached to three of its sides. Each such machine-tool head, or processing module, is able to perform a different manufacturing process. These tool heads are interchangeable, enabling the cell to be configured to process a wide range of components with different materials, dimensions, tolerances and specification. Additional components of the cell include manipulation robots and an automated buffer unit. Such cells can be integrated into a manufacturing system via a modular conveyor belt to transfer parts from one cell to another and into assembly. A key consideration of the architecture is a control system that is also modular and reconfigurable; such that when new processing modules are introduced the control system is aware of the change and adjusts accordingly. Further to this coordination, issues between modules and machining cells are also considered. Other design considerations include work-piece holding and manipulation.
This paper provides an overview of the architecture, the key design and implementation challenges as well as a high level operational performance assessment by means of a discrete event simulation model of the micro factory cell
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E-learning adoption in higher education in Jordan: vision, reality and change
This paper discusses the implementation of an e-learning program at a Jordanian University (Al-Ahliyya Amman University). The program originally aimed to establish a virtual university which offers totally online courses but due to a number of reasons there had to be some changes in the implementation process. The paper discusses such changes and challenges faced by AAU in implementing its e-learning program from an IS project management point of view. Findings suggest that implementing such projects needs careful consideration of a variety of issues to ensure that the objectives are achieved. The case provides rich insights to other educational institutions wishing to implement such projects
Passive Design of Buildings for Extreme Weather Environment
Buildings account for nearly 40% of the end-use energy consumption and carbon emissions globally. Buildings, once built, are used at least for several decades. The building sector therefore holds a significant responsibility for implementing strategies to increase energy efficiency and reduce carbon emissions and thus contribute to global efforts directed toward mitigating the adverse effects of climate change. The work presented in this paper is a part of continuing efforts to identify, analyze and promote the design of low energy, sustainable buildings with special reference to the Kazakhstan locality. Demonstration of improved environmental conditions and impact on energy savings will be outlined through a case study incorporating a passive design approach and detailed computational fluid dynamics analysis for an existing building complex. The influence of orientation and configuration is discussed with reference to energy efficiency and associated wind comfort and safety. The effect of these aspects on energy consumption and comfortable wind environment has been assessed using CFD analysis and proved to be affective. Single building and multiple building configurations have been analyzed and compared. According to the findings, multiple building configurations have better wind conditions when compared with a single standing building. With respect to orientation the former one should be modeled with the fully surrounded side of a âboxâ opposite to the predominant wind direction whereas the latter one should be located with the rear side opposite to the wind direction. Thus, results indicated that there is a considerable influence of passive design and orientation on energy efficiency, wind comfort and safety. Careful consideration and application of the findings can potentially lead to considerable decrease of energy consumption and, therefore, allow saving money and the environment at the same time
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Factors impacting knowledge transfer success in information systems outsourcing
Despite increased research interest on knowledge transfer in information systems (IS) outsourcing, the field still lacks sound and holistic understanding of the key factors influencing knowledge transfer success. The present paper attempts to provide a synthesis of existing theoretical perspectives and empirical findings related to the factors that facilitate or hamper knowledge transfer success in IS outsourcing. The data collection method is discussed and the key findings are presented. Conclusion is drawn and further research is suggested
On the Thermodynamic Bethe Ansatz Equation in Sinh-Gordon Model
Two implicit periodic structures in the solution of sinh-Gordon thermodynamic
Bethe ansatz equation are considered. The analytic structure of the solution as
a function of complex is studied to some extent both analytically and
numerically. The results make a hint how the CFT integrable structures can be
relevant in the sinh-Gordon and staircase models. More motivations are figured
out for subsequent studies of the massless sinh-Gordon (i.e. Liouville) TBA
equation.Comment: 32 pages, 18 figures, myart.st
Reconfigurable wideband patch antenna for cognitive radio
Cognitive radio communication is envisaged to be a new paradigm of methodologies for enhancing the performance of radio communication systems through the efficient utilization of radio spectrum. A key enabler for realization of a cognitive communication system is the capability of re-configurability in the underlying hardware and the associated protocol suite. Reconfigurable double C-Slot microstrip patch antenna fed by 50 ohm microstrip line is proposed in this paper. The frequency tuning is performed by switching on and off two patches. The antenna can operate in dual-band or in very wide band mode in 5, 6 and 7
GHz bands. The wide-band mode can be obtained when both switches are in the ON state with impedance bandwidth of 33.52
% from 4.99 to 7 GHz. The total size of the ground plane is 50 x 50 mm2. The proposed antenna verified through both numerical
simulation and measurement of an experimental prototype. The antenna achieves a gain of 5 to 8 dBi and radiation efficiency
about 80%
Numerical solution of the two-dimensional Helmholtz equation with variable coefficients by the radial integration boundary integral and integro-differential equation methods
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Taylor & Francis.This paper presents new formulations of the boundaryâdomain integral equation (BDIE) and the boundaryâdomain integro-differential equation (BDIDE) methods for the numerical solution of the two-dimensional Helmholtz equation with variable coefficients. When the material parameters are variable (with constant or variable wave number), a parametrix is adopted to reduce the Helmholtz equation to a BDIE or BDIDE. However, when material parameters are constant (with variable wave number), the standard fundamental solution for the Laplace equation is used in the formulation. The radial integration method is then employed to convert the domain integrals arising in both BDIE and BDIDE methods into equivalent boundary integrals. The resulting formulations lead to pure boundary integral and integro-differential equations with no domain integrals. Numerical examples are presented for several simple problems, for which exact solutions are available, to demonstrate the efficiency of the proposed methods
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