32 research outputs found

    Decreased soluble cell adhesion molecules after tirofiban infusion in patients with unstable angina pectoris

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    AIM: The inflammatory response, initiated by neutrophil and monocyte adhesion to endothelial cells, is important in the pathogenesis of acute coronary syndromes. Platelets play an important role in inflammatory process by interacting with monocytes and neutrophils. In this study, we investigated the effect of tirofiban on the levels of cell adhesion molecules (soluble intercellular adhesion molecule-1, sICAM-1, and vascular cell adhesion molecule-1, sVCAM-1) in patients with unstable angina pectoris (AP). METHODS: Thirty-five patients with unstable AP (Group I), ten patients with stable AP (Group II) and ten subjects who had angiographycally normal coronary arteries (Group III) were included the study. Group I was divided into two subgroups for the specific treatment regimens: Group IA (n = 15) received tirofiban and Group IB (n = 20) did not. Blood samples for investigating the cell adhesion molecules were drawn at zero time (baseline; 0 h) in all patients and at 72 h in Group I. RESULTS: The baseline levels of sICAM-1 and sVCAM-1 were higher in Group I than in Groups II and III. They were higher in Group IA than in Group IB. However, the sICAM-1 and sVCAM-1 levels decreased significantly in Group IA after tirofiban infusion. In contrast, these levels remained unchanged or were increased above the baseline value in Group IB at 72 h. CONCLUSION: The levels of cell adhesion molecules in patients with unstable AP decreased significantly after tirofiban infusion. Inhibition of platelet function by specific glycoprotein IIb/IIIa antagonists may decrease platelet-mediated inflammation and the ischemic end-point

    The effects of perforated cylinders on the vortex shedding on the suppression of a circular cylinder

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    The aim of this study is the control of unsteady vortical flow occurred downstream of a circular cylinder located in shallow water flow using concentrically located outer perforated cylinder. The porosities, β have been changed between 0.1 and 0.8 in the present study. The increments of porosity β were taken as 0.05 in the range of 0.1 and 0.8 with a hole diameter of d=10 mm. The ratio of inner cylinder diameter to outer cylinder diameter, Di/Do was selected as 0.25, 0.3, 0.4, 0.5 and 0.6 the inner cylinder diameter is Di=50mm where the outer cylinder diameter is Dd=100mm. Experiments were performed at a constant depth of the water level as h=50mm (half of the outer cylinder diameter). Free stream velocity was taken as U∞=100 mm/s corresponding to a Reynolds number of Re Do=10000 based on the outer cylinder diameter. It has been observed that the inner circular cylinder was highly affected by the existence of surrounding outer perforated cylinders. It is observed that the intensity of Reynolds shear stress correlating, is completely attenuated in the region both downstream of concentric cylinder and between the concentric cylinders. It is determined from the experiments that porosity, β=0.55 is the most effective parameter for control of flow structure that is occurred from the inner cylinder

    Flow past a square prism with an upstream control rod at incidence to uniform stream

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    WOS: 000363345800042In the numerical study, it was mainly intended to test the capability of a control rod to reduce the drag and to suppress the fluctuating forces acting on the rod-square (total) system for various angles of incidence (alpha) and center-to-center spacing ratios (L/D). The Reynolds numbers (Re) based upon the diameter of control rod and the side length of the square prism are 50 and 200, respectively, for the control rod and the square prism. Seven distinct flow patterns were observed and it was demonstrated that the cavity flow pattern is the most effective in terms of simultaneous reduction of the time-averaged and RMS values of fluctuating force coefficients for both control rod and square prism. As the control rod located 2D or 3D upstream of the square prism at zero angle of incidence, the time-averaged drag coefficient of the total system i.e. the sum of the time-averaged drag coefficients of the control rod and the square prism is about 74% that of the square prism alone. Furthermore, the maximum reductions in RMS values of the fluctuating lift acting on the total system are 53% and 60%, respectively, for 2D and 3D. On the other hand, the effectiveness of control rod in reducing the time-averaged drag coefficient of the total system was generally diminished with increasing a. Instantaneous and time-averaged flow fields were also presented in order to identify the flow patterns around the rod-square system. (C) 2015 Elsevier Ltd. All rights reserved.Scientific and Technological Research Council of Turkey (TUBITAK) [105M241]The authors gratefully acknowledge the financial support from the Scientific and Technological Research Council of Turkey (TUBITAK) for this study through grant number of 105M241

    Large Conization and Laparoendoscopic Single-Port Pelvic Lymphadenectomy in Early-Stage Cervical Cancer for Fertility Preservation

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    Fertility preservation in early-stage cervical cancer is a hot topic in gynecologic oncology. Although radical vaginal trachelectomy (RVT) is suggested as a fertility preserving approach, there are some serious concerns like cervical stenosis, second trimester loss, preterm delivery in survivors, and lack of residual tumor in the majority of the surgical specimens. Therefore, less radical surgical operations have been proposed in early-stage cervical carcinomas. On the other hand, single-incision laparoscopic surgery (SILS) is an evolving endoscopic approach for minimal access surgery. In this report, we present a case with early-stage cervical cancer who wishes to preserve fertility. We successfully performed single-port pelvic lymphadenectomy and large conization to preserve fertility potential of the patient. We think that combination of less radical approach like conization and single-port pelvic lymphadenectomy might be less minimally invasive and is still an effective surgical approach in well-selected cases with cervical carcinomas. Incorporation of single-port laparoscopy into the minimally invasive fertility sparing management of the cervical cancer will improve patients outcome with less complications and better cosmesis. Further studies are needed to reach a clear conclusion

    Flow structures in end-view plane of slender delta wing

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    Present investigation focuses on unsteady flow structures in end-view planes at the trailing edge of delta wing, X/C=1.0, where consequences of vortex bursting and stall phenomena vary according to angles of attack over the range of 25° ≤ α ≤ 35° and yaw angles, β over the range of 0° ≤ β ≤ 20°. Basic features of counter rotating vortices in end-view planes of delta win with 70° sweep angle, Λ are examined both qualitatively and quantitatively using Rhodamine dye and the PIV system. In the light of present experiments it is seen that with increasing yaw angle, β symmetrical flow structure is disrupted continuously. Dispersed wind-ward side leading edge vortices cover a large part of flow domain, on the other hand, lee-ward side leading edge vortices cover only a small portion of flow domain

    Passive control of flow structure interaction between a sphere and free-surface

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    Flow characteristics for both a smooth and a vented sphere such as velocity vectors, patterns of streamlines, vorticity contours, stream-wise fluctuations, cross-stream velocity fluctuations and Reynolds stress correlations between a sphere and free-surface for various submerged ratio at Re =5,000 are studied by using dye visualization and the particle image velocimetry technique. Passive control of flow structure interaction between sphere and free surface was examined by using a modified geometry which has a 15% sphere diameter hole passing through the sphere equator. Both of the spheres were separately placed beneath the free surface with different positions from touching to the free surface to two sphere diameters below the free surface. It is demonstrated that reattachment point of the separated flow to the free surface varies for both of the sphere cases as the sphere position alters vertically through the water flow while the flow structure for the vented sphere occurs considerably symmetrical due to forming of a pair of counter-rotating ring vortices

    Investigation of interactions between a sphere wake and free surface

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    WOS: 000444464000025This paper presents flow-structure interaction between a sphere wake and a free water surface for different submerged elevations in an open water channel for Reynolds numbers in the range of 2.5x10(3) <= Re <= 1x10(4) based on the diameter of the sphere. Particle Image Velocimetry (PIV) and dye visualization techniques were performed to demonstrate flow patterns such as instantaneous and time-averaged velocity field, streamline topology, vortices, velocity contours. The sphere was fixed at various submerged locations from the piercing the free surface case to the two sphere diameters beneath the free surface in the range of 0.25 <= h/D <= 3.0. Here, submerged ratio was defined as ratio of bottom shoulder of the sphere from the free surface to the sphere diameter. Depending on the sphere locations, characteristics of wake region exhibit three different flow phenomena. These are classified as; a restricted wake region between the free-surface and uniform flow stream for the submerged ratios of 0.25 <= h/D <= 1.0, unsymmetrical flow patterns due to the free surface effect for the submerged ratios of 1.25 <= h/D <= 2.0 and symmetrical flow structures for the submerged ratios of 2.5 <= h/D <= 3.0 More detailed results for the aforementioned flow structures from the point of flow physics were comparatively presented and interpreted.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [109R028]The Scientific and Technological Research Council of Turkey (TUBITAK-Project No: 109R028), Scientific Research Projects Office of Cukurova University and Selcuk University's Scientific Research Project Offic

    Turbulent shear flow downstream of a sphere with and without an o-ring located over a plane boundary

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    Flow-structure interaction of separated shear flow from the sphere and a flat plate was investigated by using dye visualization and the particle image velocimetry technique. Later, a passive control method was applied with 2mm oring located on the sphere surface at 55° from front stagnation point. The experiments were carried out in open water channel for Reynolds number value of Re=5000. Flow characteristics have been examined in terms of the 2-D instantaneous and time-averaged velocity vectors, patterns of vorticity, streamlines, rms of velocity fluctuations and Reynolds stress variations and discussed from the point of flow physics, vortex formation, lengths of large-scale Karman Vortex Streets and Kelvin-Helmholtz vortices depending on the sphere locations over the flat plate. It is demonstrated that the gap flow occurring between the sphere bottom point and the flat plate surface has very high scouring effect until h/d=0.25 and then unsymmetrical flow structure of the wake region keeps up to h/D=1.0 for smooth sphere. For the sphere with o-ring, the wake flow structure becomes symmetrical at smaller gap ratios and reattachment point on the flat plate surface occurs earlier. Moreover, o-ring on the sphere diminishes peak magnitudes of the flow characteristics and thus it is expected that the flow-induced forces will be lessened both on the sphere and flat plate surface. Vortex formation lengths and maximum value occurring points become closer locations to the rear surface of the sphere with o-ring
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