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All bioresorbable polymeric implants are radiolucent, making them undetectable under the X-rays. Therefore, to improve their X-ray visibility, the high effective atomic number (Zeff) material such as Pt, Au, Ta, Ba, or its alloy are attached to the body of the bioresorbable implant. However, during the in vivo degradation, these bio-inert heavy metals can either detach or leach out from the lesion site and accumulate into the vital organ, leading to severe health complications. Thus, as a strategy, the novel biodegradable and radiopaque Mg alloy was produced to impart X-ray visibility in the biopolymer. Here, the Mg was alloyed with the optimized ratio of heavy metals, i.e., Zn and Y. The radiopaque Mg alloy was characterized and powdered to the size of 25–20 µm. Further, it was blended with radiolucent Poly-L-lactic acid (PLLA) and polycaprolactone (PCL) polymer. The Bi-axially expanded (BAE) tubes of PLLA/PCL and PLLA/PCL/Mg alloy (5% wt.) were extruded for fabricating cardiovascular stents. The BAE tube comparison studies were performed for thermal stability, wettability, surface roughness, and mechanical properties. The potential of 5% Mg alloy in the polymeric matrix was evaluated as a nucleating, reinforcing, and radiopaque agent. In vitro accelerated degradation study was performed in the physiological fluid to evaluate the pH variation and decomposition rate. Finally, in vitro biocompatibility was assessed by evaluating the behavior of L929 fibroblast cells, followed by the blood biocompatibility test on the blends. [ABSTRACT FROM AUTHOR]

The effectiveness of cardiovascular stenting procedure depends on the crimping and expansion characteristics of a stent, influenced by its design parameters. In this study, CoCr stents are fabricated, crimped on a tri-folded balloon, and expanded using manual inflation device. Similarly, in the finite element model, a tri-folded balloon is used to expand the stent. The length and diameter are measured to evaluate the radial strength, recoil, foreshortening, and dogboning. The simulation and experimental results match satisfactorily. The validated FE model can be used with confidence to optimize future stent designs, thus reducing the number of testing and product development time. [ABSTRACT FROM AUTHOR]

In this study, influence of blowing agent residence conditions on foam attributes has been investigated in extrusion foaming process. The blowing agent injection location in the extrusion barrel was found to affect the residence time inside the barrel, which in turn significantly transformed the foam microstructure. The injection location providing higher gas residence time resulted in foams with lower cell size, higher expansion ratio, and enhanced cell density. Further studies were performed to analyze the synergistic influence of residence time variation on foam attributes at different screw rotational speeds, die temperatures, and blowing agent contents. [ABSTRACT FROM PUBLISHER]

Low-velocity-impact experiments were performed on a unidirectional laminate [0°]8and cross-ply laminate [0°/90°]4of E-glass/epoxy composite of thickness of 6.4 mm for incident energies 6.9 J, 9.48 J, and 12.7 J. The energy, contact forces, and displacement plots with respect to time are studied for a drop test. The damage observed as a back face signature on the back face of both cross-ply and unidirectional laminate are plotted. The composite was speckled randomly and the impact phenomenon was recorded using a high-speed camera. The DIC data were analyzed to obtain displacement and strains on the surface of the plate. [ABSTRACT FROM AUTHOR]

Pelvic prolapse affects one woman in three of all ages combined and is quite common for more than 60% of patients over 60 years of age. The treatment of this pathological problem is one of the biggest challenges to the gynaecologist today. The rate of surgical intervention failure is quite significant. The recurrence of prolapse could be related to inadequate surgical technique or the pathology or/and biomechanical deficiency of the soft tissues. The modelling and simulation of the behaviour of the pelvic cavity could be a major tool for specific evaluation of pelvic status. A first stage of this model is being developed and reported. The computer-aided design model of the organs of the pelvic floor is created using magnetic resonance image data and the ligament boundary conditions are defined. A multi-organ geometric model is thus created and studied. [ABSTRACT FROM AUTHOR]

A continuous production of microcellular polypropylene (PP)/30% carbon fiber composite was achieved in a newly developed nozzle-based microcellular injection molding system. In this work, a conventional injection molding machine was retrofitted with a nitrogen (N2) gas injection system. A specially designed “injection cum mixing nozzle” was added between the machine barrel and a shut-off nozzle to form a polymer/gas mixture as against barrel injection where the screw and barrel are usually modified for gas insertion. The foamed plastic was formed due to the thermodynamic instability caused by sudden pressure drop in the mold. The effectiveness of foam molding system developed in this study was verified by change of process parameters resulting into variety of cell morphology and cell size. Further, PP/30% carbon fiber composite was injection molded into ASTM tensile test sample with both conventional and foam molding system. These samples were then subjected to scanning electron microscope (SEM) as well as tensile testing to study the effect of injection speed on the cell morphology and tensile properties of foam molded composites. It was observed that cell size decreased and cell density increased with increase in injection speed. The mechanical properties of the foamed composites depend largely on the processing conditions. [ABSTRACT FROM AUTHOR]