Showing papers by "Mansour Youseffi published in 2019"

Effect of screw configuration on the dispersion and properties of polypropylene/multiwalled carbon nanotube composite

Abstract: The effect of extruder screw configuration on the dispersion and properties of compatibilised polypropylene (PP)/Multi-walled carbon nanotube (MCNT) composite is investigated. Three principle screw designs with mainly conveying elements (medium intensity), kneading elements (high intensity) and folding elements (chaotic mixing) were used to prepare polypropylene nanocomposites containing 4wt% of maleic anhydride grafted polypropylene (MAH-g-PP) compatibilizer and different nanotube loadings. The effect of each screw configuration and nanotube loading on the tensile, rheological and electrical properties of the nanocomposites were studied. The screw configurations were found to have a strong influence on the electrical resistivity whilst only slightly affected the tensile properties of the nanocomposites. Scanning electron microscopy examinations showed that the use of screw configuration consisting of kneading elements promoted the dispersion of nanotubes and resulted in a low electrical percolation at 2wt% of MCNT.

Scaffolds for ligament tissue engineering

Abstract: This chapter of the handbook focuses on the anterior cruciate ligament of the knee, exploring its location, anatomy, physiology, and functionality within the early subsections, then leading onto conditions, injuries, diseases, and disorders of ligament tissue. Following disorders and disease, this chapter also explores the healing process of the ligament, scaffold design, fabrication techniques, and biomaterials available for ligament tissue engineering. The later subsections of this chapter focus on a review on the properties of an ideal ligament tissue scaffold, followed by the current technologies and strategies used in ligament tissue engineering and finishing up with future research in ligament tissue engineering.

Scaffolds for tracheal tissue engineering

Abstract: This chapter aims to expand the reader's knowledge on the human trachea, problems that commonly arise within the windpipe, and correctional methods for these issues, including tissue-engineered solutions. Cell derivation is covered to give examples of what could potentially work successfully and the advantages and disadvantages of specific derivations. A variety of experimental scaffold construction techniques will be discussed in detail, allowing the reader to obtain an understanding of the intricate methods required to make tissue-engineered tracheal tissue. This chapter demonstrates the extensive parameters required to make successful tissue with the ability to withstand the stresses of native tissue, while creating an environment for cells to grow and thrive on.

Scaffolds for dental cementum

Abstract: Throughout this chapter, the reader will gain an insight into the structure of the cementum, formation of the cementum, common issues associated with the cementum, and how these problems could be corrected with the use of tissue-engineered scaffold techniques. Sections on cell and biomaterial selection are included, enabling detailed breakdown of the best combination of materials. Scaffold synthesis methods are covered, with details on how previous experiments have been altered to promote higher cementum formation and how to sufficiently meet the necessary mechanical properties, to withstand the forces within the mouth. On completion of this chapter, the importance of finding alternative methods to repair cementum problems will be covered, along with sufficient information on scaffolding techniques.

Fiber-reinforced composites

Abstract: Dental application is constantly evolving as a result of innovative treatment solutions based on the development of new biomaterials, advancement in technologies, and more successful treatment techniques, with fiber-reinforced composites (FRCs) being a superb example of this The use of fibers within composite materials has greatly enhanced their uses in the field of dentistry, giving dentists more options due to the many applications of this exciting group of materials An FRC is a combination of conventional dental composite and most commonly glass fibers; this combination gives the same level of strength and flexibility that is also found in boats, light aircraft, and F1 racing cars FRCs consist of three components: (1) the matrix, this is usually made of resin and becomes a polymer after curing or polymerization Additionally, it provides a place for the fibers to reside (2) The reinforcing constituent, which is fibers of high strength and modulus; these are usually glass, carbon, or polyethylene fibers (3) The fine interphase region, also known as the interface; this is the key element of the composite as it transfers the load from the matrix to the fibers For many decades, engineers have been using fibers as high aspect ratio fillers to construct materials/devices with high levels of strength and fracture toughness Hence this is why these materials are desirable in the field of dentistry FRCs have been the center of attention in dentistry for the last two decades because of their excellent adhesion and esthetic appearance Providing them with many clinical applications, such as fixed prosthodontics, restorative dentistry, periodontology orthodontics, and in repairs of prosthetic devices

Study on Pulse Electric Field Exposure Effect on HeLa Cells For Wound Healing Application

Abstract: This study investigated the effect of pulse electric field (PEF) exposure on cervical cancer cells (HeLa cells) in an in-vitro wound repair model. The study mainly focused on the healing time of HeLa cell line wound model. During the experiments HeLa cells were maintained at 37°C in a modified Chamlide EC magnetic chamber where they were exposed to high electric fields. A Nikon inverted microscope (Ti-series) with Metamorph® time lapse software were used to monitor, image and capture photomicrographs and videos of the cells. The tests carried out during this study revealed that pulse electric field enhanced the migration of HeLa cells. Cells exposed to PEF (1kV/cm, 100μs, and single pulse) healed the wound in ~2 hours (from initial wound gap of 54.53μm ± 0.55SD to 0.66μm ± 0.61SD). On the other hand, non-PEF (control) healed the wound in ~10 hours (from initial wound gap of 56.33μm ± 0.57SD to 0.46μm ± 0.45SD). It was therefore found that the healing rate with PEF is ~five times faster than non-PEF group. It is believed that PEF usage on diseased biological cells would enable a novel method for assisting drug free wound repair systems and many other potential biomedical engineering applications such as treatment of neurological disorders including Alzheimers and Parkinsons.