Sharif Digital Repository

As diseases of eye’s posterior segment has got widespread outbreak in the world, the selection of treatment is very important. Until now, intravitreal injecton has been the most common way of drug delivery to the posterior segment. Although this method is effective, halflife of some drugs in the vitreous cavity, especially those with low molecular weight, is just about some hours. Therefore, it is necessary to repeat injection in order to maintain drug concentration level of the posterior segment in the desired level. Intravitreal injection is invasive and may cause severe adverse effects such as vitreous hemorrhage, retinal detachment, endophthalmitis and cataract. In order to decrease the... 

The in vivo cell culture process as the main part of tissue engineering was investigated through mathematical modelling and computational fluid dynamic (CFD) simulation of cartilage cell growth. Simulations can provideprocess insights for defining the optimum conditions in order to reach higher culture efficiency. In the mathematical modelling of the cell growth, it was intended to consider the most influencing factors such as biomass concentration, volume fraction, glucose concentration and shear stress levels. These results can be obtained mathematically by solving a set of partial differential equations coupling the glucose concentration, the velocity field and cell growth with each other.... 

The incidence of skeletal diseases such as osteoarthritis and its progression and the need to use knee replacement implants have significant effects on the quality of life. With the improvement of living conditions and the prolongation of the average life expectancy of the society and the aging of a large part of the society, the concern about the increase in the incidence of skeletal diseases and the need to use alternative implants increases. On the other hand, many conditions such as osteoporosis and accidents lead to fractures and cavities in the bones. Bone cements are one of the most widely used materials in orthopedic and spinal surgeries.The aim of this study was to construct a... 

In Hemodialysis, membrane dialyser and commonly hollow fibers are used to treat patients who suffer from end stage renal failure. When blood flows into membrane, it loses uremic toxins such as urea and creatinine. On the other hand, some of the vital proteins of blood pass through the membrane or they are adsorbed on the membrane surface. The more hydrophilicity of the membrane, the less adsorption of proteins is. In this study, to achieve high hydrophilicity and low adsorption of proteins on the polysulfone membrane surface, the presence of hydrophilic nano-particles SBA-15 in membrane composition is investigated. The nano-particles with mass percentages 0.25%, 0.5 % and 1 % to one mass of... 

The kidneys serve essential regulatory roles in the body which remove excess organic molecules from the blood and the removal of waste products of metabolism. They are essential in the urinary system. Urinary concentration mechanism has long been interested for mathematicians and physiologists to elucidate the obscurities within the process. In this study, a novel three-dimensional approach is used for simulating urine concentrating mechanism in rat renal medulla. The model equations are based on three spatial dimensions mass and momentum transports. Exact 3D geometry has been designed by using COMSOL Multiphysics software and results have been compared with the latest available data. In... 

Present study demonstrated carbon nanoparticles/acrylate-terminated polyurethane composites as promising materials for bone implants applications. Neat polymer and composites containing nanoparticles at different loadings up to 2 wt % were prepared by in situ polymerization method. Morphological analysis exhibited that nanoparticles caused considerable phase separation between soft and hard domains as well as increased crystallinity. Mechanical analysis showed a significant improvement in mechanical properties. Maximum improvement in tensile properties of APUA was observed at 1 wt% loading of ND-HEAMs, namely 175% improvement in modulus. In vitro biocompatibility evaluation via culturing... 

Following heart coronary artery occlusion, heart stroke (HS) happens which leads to the creation of a dead zone on heart tissue named Myocardial Infarction (MI), the presence of which on a patient’s heart will result in succeeding HSs and the death of the patient. In this study, porous microcarriers capable of being utilized in cardiovascular tissue engineering is fabricated using a mixture of myocardium ectracellular matrix (ECM) and Chitosan (Cs). Results of Elasticity tests, SEM images, swelling behavior, biodegradability test, and cell proliferation assay showed that the scaffold consisting of 3.5% (w/w) Chitosan and 0.66% (w/w) ECM has the best potential in providing cardiovascular... 

Diabetes has become the most prevalent disease all among the world. One of the complications of this disease is diabetic nephropathy. Diabetic nephropathy occurs when the kidney cells encounter high glucose concentration for long periods. Kidney cells use glucose as their energy supply. However, the excess glucose in the diabetics triggers specific gene pathways, gradually leading to diabetic nephropathy. As a result, proteins’ levels and the activity of transcription factors change during the disease progression. Diabetic nephropathy is characterized by excessive deposition of the proteins comprising the extracellular matrix in the mesangium, basement membrane of the glomerulus, and in the... 

The effects of gravity and inertia dominate our experiences of the physical world. But as systems are reduced in size, phenomena such as diffusion, surface tension and viscosity become ever more important; at the microscale they can dominate and result in a world that operates very differently from the macroscopic world. Kidney is one of the vital organs in which fluid and mass transfer occur between blood flow in microvessels and urine in microchannels called nephron. The present work is aimed at applying microchannel theory to study renal system. First, a n efficient numerical orthogonal collocation method has been employed to solve the steady-state formulation of electrolyte transport in... 

Porous polymeric particles have the extensive application in various sciences and various methods have been introduced for production of these particles. Depending on method of production, porous polymeric beads can be produced in diverse shapes, pore size, pores interconectivity, surface morphology and chemical properties. In common methods for production of porous polymeric particles, tuning the size and porosity is difficult or even impossible. Porous polymeric beads with the vast surface area and good functionality have been applied for adsorption of various materials. The purpose of this study is therefore to investigate a new procedure for the production of porous polymeric... 

PMMA bone cement lacks biodegradability and the ability to bond with surrounding bone tissue. Therefore, the development of a new generation of bioactive bone cements that are biodegradable and possess adequate mechanical properties as well as desirable setting time is receiving remarkable interest.In this study, we have developed novel mineral-based bioactive bone cements. Our mineral bioactive bone cements were composed of Calcium Sulfate Hemihydrate, Bioactive Glass, and Tricalcium Silicate. Firstly, a binary system composed of Calcium Sulfate Hemihydrate and Bioactive Glass was optimized based on mechanical and setting behavior. Secondly, Tricalcium Silicate was added to the powder phase...