background dialysis vascular access complications are considered as significant causes of morbidity in chronic hemodialysis patients. objectives the aim of the present study was a comparison of axillary loop and straight grafts patency and its complications in hemodialysis access. patients and methods in this cohort study conducted at shahid beheshti medical university, 77 patients who underwen...

closed-loop supply chain network design is a critical issue due to its impact on both economic and environmental performances of the supply chain. in this paper, we address the problem of designing a multi-echelon, multi-product and capacitated closed-loop supply chain network. first, a mixed-integer linear programming formulation is developed to maximize the total profit. the main contribution...

in this paper, firstly by using a mixed linear programming a new model of locating facilities with limited capacity is presented to design a closed-loop supply chain in a multi-product and multi-period mode. then, using a robust optimization approach, the proposed model decreases in non-deterministic expansion. the results show that the proposed model can handle facility capacity in a closed lo...

Background It is a known fact that the surgery of the anterior leaflet presents more difficulties and more dubious results than in the posterior leaflet. The use of artificial chordae is not always effective and measure its length is a challenge for the surgeon. So we present our long-term results with our new original technique for shortening the elongated chordae we call, “twisting loop techn...