Sharif Digital Repository

As the first barrier in front of external damages, skin is prone to the largest number of damages applied to one’s body. Acute wounds are considerably prevalent world-widely, imposing very high costs to governments. The purpose of the current project, is to propose a novel skin scaffold capable of growth factor delivery for enhancing the wound healing process in acute wounds. Such a scaffold should be able to decrease the required time for healing process, also to improve the quality of the regenerated skin compared to available commercial products. Furthermore, it should be highly biocompatible, biodegradable, and non-toxic. In this project, to manufacture the artificial skin scaffold, a... 

Skin tissue as the first protective barrier to the body is always exposed to the most injuries. The purpose of this project is to design an optimum skin scaffold capable of drug delivery for skin wounds healing. To this end, the skin scaffold has been considered as a combination of a hydrogel structure containing polymer microspheres carrying growth factor. Polyvinyl alcohol and sodium alginate polymers were utilized to make the hydrogel substrate. The hydrogel structure was optimized from the viewpoint of the percentage of gelation, water absorption, porosity, mechanical properties, biodegradability, biocompatibility and considering the volume percent of utilized polymers and the... 

Cancer diagnosis area has recently been in the limelight of the medical research and there exist an unremitting focus on the devices & technologies which enable cancer detection in its victims. Lately a genius diagnostic method based on isolation and entrapment of circulating tumor cells has been developed which pave the path for cancer identification. These circulating cells which are detached from the primary tumor are carried out through body by means of circulation system. They play key role in phenomenon called metastasis. Separating these rare cells from multifarious background blood cells, assessing their quantity can supply valuable information on the stage of disease as well as its... 

In humans, the heart is roughly the size of a large fist and weighs between about 280 to 340 grams in men and 230 to 280 grams in women. Your body has about 5.6 liters of blood. The human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. Any damage to the heart, will affect on the other organs. They are four valves within the heart, in which aortic valve is the most important and crucial part of the heart. Calcium sediment on aortic valve leaflets causes reduction in the flexibility of the leaflets, one of the most common heart diseases. In this study, the flexibility... 

Particle separation has a variety of applications in biology, chemistry and industry. Among them, circulating tumor cells (CTCs) separation has drawn significant attention to itself due to its high impact on both cancer diagnosis and therapeutics. In recent years, there has been growing interest in using inertial microfluidics to separate micro/nano particles based on their sizes. This technique offers label-free, high throughput, and efficient separation and can be easily fabricated. However, further improvements are needed for potential clinical applications. In this study, a novel inertial separation technique using spiral microchannel with stair-like cross section is introduced. The... 

Kidney stone disease is one of the diseases that a large number of people experience each year.A Common method for the treatment of kidney stone is the use of acoustic waves, which have attracted the attention of doctors in recent decades. Because of the different structure of kidney stones, the waves transmitted to break these stones are usually performed at different frequencies. Most kidney stones are calcium that can be broken down by using acoustic wave frequencies in the range of 40-20 KHz. Most available lithotripters for the treatment of percutaneous nephrolithotomy (PCNL) are two types: Pneumatic and piezoelectric lithotripters. The lithotripter in this thesis is a piezoelectric... 

Currently, the HIFU (High Intensity Focused Ultrasound) therapy method is known as one of the most advanced surgical techniques in tumor ablation therapy. Simulation of the HIFU therapy in the case of appearance of bon barrier is essential in HIFU planning to improve the usefulness and efficiency of treatment in brain tumor cases. In this work, linear, thermoviscous equations are applied for simulation of phase correction array and steering method, after analysis of performance, these methods are used in a 3D human brain and skull model to estimate thermal ablation in case of using these methods. Results indicate that the maximum focal pressure of 1.42 and 1.65 MPa can be achieved for... 

With the advent of new computer technologies, computational analysis on the human organs has become tremendously popular in the field of medical science. Every year thousands of people suffer irreversible eye damages pertaining to lack of adequate medications. In this regards, enormous amount of money is spent annually but mostly in vain due to the irreversibility and silent nature of eye diseases like glaucoma. Yet more precise studies on the topic are requisite. In this thesis, a validated half 3D finite volume model of human eye considering the fluid flow in collaboration with heat transfer in the steady state utilizing the well known discretized bio-heat transfer equation coupled with... 

In this study, the linear dynamic response of an inclined FGM Timoshenko beam on linear viscoelastic foundation subjected to a traveling mass with constant and variable velocity is investigated. Timoshenko beam theory and von-karman strain-displacement relations are utilized to model the problem. the FGM beam is made of metal and ceramic and it is assumed that material properties of the beam vary continuously in the thickness direction according to the exponential law and the power-law form. The kelvin-voigt damping model is applied to model the internal damping of the FGM beam. The partial differential equations of motion for the bending rotation of cross-section, longitudinal and... 

The recent breakthroughs in the lab-on-a-chip technology will not be directly used as clinical devices unless the specific applications are carefully tested and certified. As there is a growing trend towards microfluidic devices for biomedical research, an active microfluidic device was developed. Common microfabrication methods were used to develop a microchip to separate and concentrate live and dead cells based on the dielectrophoresis phenomenon. Unique capabilities of the dielectrophoresis phenomenon make it a powerful tool for micro particle manipulation in micro scale. In this research, geometry for the mentioned purpose is designed and optimized. Three-dimensional microelectrodes are... 

Articular cartilage Function is vital to joint tasks and its motion. The main biomechanical tasks of articular cartilage are a) the distribution of loads occurred in joints; b) providing joints with frictionless surface. The particular mechanical properties of articular cartilage make it possible for the Cartilage tissue to do its duty successfully. The biological factor that causes articular cartilage to damage is still unknown. It is believed that mechanical factors are the main reason for the cartilage destruction in osteoarthritis. Factors like age, heavy exercises and impact can begin tissue destructions and result in change in mechanical properties. To study the process of the... 

Metallic implants are often used in the open reduction and internal fixation of fractures. Open reduction and internal fixation are commonly used in cases of trauma when the bone cannot be healed using external methods such as casting. The locking compression plate combines the conventional screw holes, which use non-locking screws, with locking screw holes, which use locking head screws. This allows for more versatility in the application of the plate.
In the present work, the stress (von-mises) and deformation of a locking compression plate fixed across a transverse fracture (2-mm gap) at the midshaft of femur was evaluated by Ansys software. Femur model is divided to two part... 

In femoral neck fracture when the non-union happens in the fractured zone, valgus osteotomy is a surgery method to overcome bone non-union. In this method, a wedge osteotomy-with specific depth and angle- at the femoral neck is created. By changing the bone angle at the fracture site and the angle of the wedge osteotomy it is desired to convert the shear stress to the normal stress. Clinically it is believed that this would facilitate bone healing and prevent bone fracture. This surgery method also changes the anatomy of muscles due to changing hip anatomy, joint reaction force , and it’s direction. This procedure while minimizing shear stress it also reduces the blood supply to the area and... 

Researches in last decades have shown that biological cell’s functionality is related to the way of their deformation in response to forces and stresses exerted on the cell. Therefore designing microsensors with easy and economical applicationswhich are capable for determining cell mechanical properties seems to be logical. In this project using an electrostatically actuated microbeam with both clamped ends equipped with an indenter at midpoint to transmit force on the cell, proposed as a technique to apply axial load on the cell. Inthis research by implementation of approximated methods for solving nonlinear algebraic and differential equations, governing on microbeam deflection, it has...