A novel design of a polymeric aortic valve.

Introduction: In this paper we propose a novel method for developing a polymeric heart valve that could potentially offer an optimum solution for a heart valve substitute. The valve design proposed will provide superior hydrodynamic performance and excellent structural integrity. A full description of the design process is given together with an analysis of the hemodynamic performance using a 2-way strongly coupled Fluid Structure Interaction (FSI).

Graft-artery junctions: design optimization and CAD development.

Designing and manufacturing of vascular prosthesis for arterial bypass grafts is a very complex problem. The process involves the selection of suitable geometry, materials of appropriate characteristics, and manufacturing technique capable of constructing prosthesis in a cost-effective manner. In this chapter, all engineering aspects related to the design and optimization of an artificial graft are presented and discussed.

Numerical analysis of coronary artery bypass grafts: an over view.

Arterial bypass grafts tend to fail after some years due to the development of intimal thickening (restenosis). Non-uniform hemodynamics following a bypass operation contributes to restenosis and bypass failure can occur due to the focal development of anastomotic intimal hyperplasia. Additionally, surgical injury aggravated by compliance mismatch between the graft and artery has been suggested as an initiating factor for progress of wall thickening along the suture line Vascular grafts that are small in diameter tend to occlude rapidly.

Microwave sterilization of bovine pericardium for heart valve applications.

It is widely recognised that the bioprosthetic valves widely used for heart valve replacements have some drawbacks, for example tearing and occurrence of infections, which can be attributed to the fixation and sterilization techniques currently available. These techniques adversely affect the physical properties, functionality, and lifespan of the leaflets. In the work discussed in this paper we examined a novel procedure of using high-frequency microwaves to fix and disinfect the pericardium, without causing any harmful affects.

Breast-cancer identification using HMM-fuzzy approach.

This paper presents an ensemble of feature selection and classification technique for classifying two types of breast lesion, benign and malignant. Features are selected based on their area under the ROC curves (AUC) which are then classified using a hybrid hidden Markov model (HMM)-fuzzy approach. HMM generated log-likelihood values are used to generate minimized fuzzy rules which are further optimized using gradient descent algorithms in order to enhance classification performance.

Gentamicin-impregnated chitosan/nanohydroxyapatite/ethyl cellulose microspheres granules for chronic osteomyelitis therapy.

In this article gentamicin (GM) impregnated microspheres were used to extend the drug release time for the treatment of chronic osteomyelitis. The granules were prepared in solution and consisted of nanohydroxyapatite (nHA), chitosan (CS) and GM loaded ethyl cellulose (EC) microspheres. A rabbit model with chronic osteomyelitis was made by using staphylococcus aureus and morrhuate sodium and special inspection methods were used to test the curative effects of the granules, such as microbiological investigations, tissue, and X-ray observations.

A new sterilization technique of bovine pericardial biomaterial using microwave radiation.

Bioprosthetic valves created from chemically treated natural tissues such as bovine pericardial biomaterial are used as heart valve scaffolds. Methods currently available for sterilization of biomaterial for transplantation include the application of gamma radiation and chemical sterilants. These techniques, however, can be problematic because they can be expensive and lead to a reduction in tissue integrity.

Improved properties of incorporated chitosan film with ethyl cellulose microspheres for controlled release.

In this article, to discover an innovative drug release system, ciprofloxacin hydrochloride-loaded blending films of chitosan (CS)/ethyl cellulose (EC) microspheres were prepared. Two steps were adopted in the film forming process. The first was formation of the drug-loaded EC microspheres in CS solution by solvent remove/solvent evaporation methods; then, the composite films were made by casting and solvent evaporation.

A reinforced sternal wiring technique for transverse thoracosternotomy closure in bilateral lung transplantation: from biomechanical test to clinical application.

Objectives: A high incidence of failure of transverse thoracosternotomy closure, involving the loops of wire cutting through the sternum, remains a significant morbidity after bilateral lung transplantation. We postulated that placing peristernal wires inside the usual longitudinal wires could prevent the longitudinal wires from cutting through the sternum. The aims of this study were to investigate the biomechanical and clinical efficacy of the proposed reinforced sternal closure technique.

Development of a novel pulsatile bioreactor for tissue culture.

The construction of tissue-engineered parts such as heart valves and arteries requires more than just the seeding of cells onto a biocompatible/biodegradable polymeric scaffold. It is essential that the functionality and mechanical integrity of the cell-seeded scaffold be investigated in vitro prior to in vivo implantation. The correct hemodynamic conditioning would lead to the development of tissues with enhanced mechanical strength and cell viability.

Polyethyleneterephthalate provides superior retention of endothelial cells during shear stress compared to polytetrafluoroethylene and pericardium.

Background: Polyethyleneterephthalate (PET) and polytetrafluoroethylene (PTFE) are polymers successfully used as large diameter arterial grafts for peripheral vascular surgery. However, these prosthetic grafts are rarely used for coronary bypass surgery because of their low patency rates. Endothelialisation of the lumenal surface of these materials may improve their patency.

Tissue engineering a functional aortic heart valve: an appraisal.

Valvular heart disease is an important cause of morbidity and mortality, and currently available substitutes for failing hearts have serious limitations. A new promising alternative that may overcome these shortcomings is provided by the relatively new field of tissue engineering (TE). TE techniques involve the growth of autologous cells on a 3D matrix that can be a biodegradable polymer scaffold, or an acellular tissue matrix.