EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

An efficient approach for in-plane free and forced vibrations of axially functionally graded parabolic arches with nonuniform cross section

This article presents an effective approach for analyzing the in-plane free and forced vibration responses of axially functionally graded (AFG) parabolic arches with a nonuniform cross section. Material and geometric properties of the arch are considered to vary continuously along the axial direction of the arch. The effect of shear deformation is considered in the formulations. The governing differential equations of motion are solved by the Complementary Functions Method (CFM) in the Laplace domain. Furthermore, in the damped forced vibration case, the Kelvin model is employed. A detailed study is carried out to demonstrate the effects of material variations on the natural frequencies and on the transient response of the AFG arches. Current results are compared with the numerical results of ANSYS to confirm the validity and effectiveness of the present approach. Effects of the material index on dynamic behavior of the AFG structures are examined. It is believed that derived results can be used as benchmark solutions for validation of future works on the dynamic behavior of AFG arches. © 2018 Elsevier LtdFirat University Scientific Research Projects Management Unit: FDK-2017-8254The authors thank the Scientific Research Projects Directorate of Cukurova University for supporting the present study ( FDK-2017-8254 ) and the Scientific and Technical Research Council of Turkey (TÜBİTAK) for supporting the Ph.D. program of Ahmad Reshad Noori at Cukurova University

Dynamic response of viscoelastic tapered cycloidal rods

This paper describes a unified approach to utilize the free vibration, damped and undamped forced vibration responses of isotropic and homogeneous cycloidal rods of non-uniform cross-section. The governing equations of motion of the considered structures are solved by the Complementary Functions Method (CFM) in the Laplace domain. The fifth-order Runge–Kutta (RK5) algorithm has been applied for the numerical solution of the obtained differential equations. The effect of shear deformation is also taken into account. The Kelvin model is used to describe the viscoelastic properties. For the suggested model two computer programs are coded in Fortran. Verification of the written programs is performed by comparing the results of the presented method and results of ANSYS. It has emerged that the proposed method yields highly accurate and computationally low cost results and it is more efficient than conventional step-by-step time integration approaches. It is believed that results of the presented method can be used as benchmark solutions for future researches. © 2018 Elsevier LtdThe authors thank the Scientific and Technical Research Council of Turkey (TÜBİTAK) for supporting the Ph.D. program of Ahmad Reshad Noori at Cukurova University

Damped transient response of in-plane and out-of-plane loaded stepped curved rods

This paper focuses on the damped and undamped transient response of in-plane and out-of-plane loaded stepped curved rods. A unified approach combining the complementary functions method with the Laplace transform is applied to examine the dynamic behavior of above structural elements, while the materials are assumed to be isotropic and homogeneous. The effect of shear deformation is also taken into account. As examples, the forced vibration analysis of a stepped circular arch subjected to step, triangular impulsive and rectified sinusoidal wave in-plane loads and a stepped circular rod under the step, pulse and square wave out-of-plane loads are presented. To validate and compare the results of the present study, two computer programs are coded in Fortran. Verification and exactness of the written programs are performed by comparing the results of the present method and results of ANSYS which is a conventional finite element program. It has emerged that present method is highly accurate and efficient compared to conventional step-by-step integration methods. © The Brazilian Society of Mechanical Sciences and Engineering 2018.Acknowledgement The authors thank the Scientific and Technical Research Council of Turkey (TÜBİTAK) for supporting the Ph.D. program of Ahmad Reshad Noori at Cukurova University