Sharif Digital Repository

Kidney transplants are vital for patients with end-stage kidney disease. Therefore, it is essential to allocate kidneys to patients efficiently. Kidney Exchange Programs allow patients with incompatible donors to exchange donors and receive a suitable kidney. In practice, these exchanges occur within cyclic or chain-like structures. Planned transplants may be canceled before the transplant takes place, for a variety of reasons. Failure of one transplant in a cycle or chain can result in the failure of all transplants in that cycle or chain, which can lead to drastic inefficiency in the exchange program.In this thesis, we study kidney exchange programs under uncertainty. We consider... 

The kidney is one of the most complicated organs in terms of structure and physiology, in part because it is highly vascularized. Previous investigations have focused on specific characteristics like length and diameter. There are a few methods like those which are based on image processing techniques, that have been focused on all features as a unique structure. The clear drawback of these approaches is inability to justify growth and changes. Lindenmayer system (L-system) is parallel rewriting method and a type of graph grammars. L-system can justify growth and all characteristic changes and adopt itself to them. Parametric rewriting rules incorporating within physiological laws of 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... 

One of the most efficient techniques deployed for end-stage renal disease remedy is kidney transplantation, but in this case, we commonly encounter with the problem of gap between the demand of patients and supply of donors. In the majority of models has been proposed until now, either kidney exchange technique in a pool of incompatible pairs or kidney allocation system from deceased donors to waiting list is recommended. In this research, in order to enhance kidney transplantation plans, first, a hybrid conceptual model is proposed. Then, its mathematical model is discussed, in which some of the transplantations are selected from kidney allocation system before injecting to the pool of... 

The human body normally has two functioning kidneys, while only one of them is sufficient to have a healthy life. However, for those patients having no functioning kidney, transplantation is the most effective treatment. Although deceased donors have been usually used as the main source for kidney donation in many countries, there are several cases focusing on living kidney donation to compensate for the shortage in supply and to reduce the patient waiting time for treatment. Because of this potential, many studies have been conducted to optimize the non-clinical issues of kidney transplant waiting lists. Notwithstanding employing the financial incentives for living kidney donation is... 

As the number of patients waiting for receiving kidney transplantation increases all over the world, the average waiting time for a patient in queue rises too, and consequently, the rate of death goes beyond the accepted level. Also, unbalanced numbers of donors and patients with same blood type make the problem bolder. The aim of this research is to design a queuing model in which kidney could be transplanted from deceased donors to patients with different but compatible blood type (Cross-Transplantation) in order to make the average waiting time for patients with different blood type closer to each other. In other words, the transplant system is supposed to make a decision whether to... 

One of the most common and effective ways to treat end-stage renal disease is the use of kidney exchange techniques. However, the main problem with this treatment is the presence of many barriers to allocating kidney pairs to each other, which reduces the success of kidney transplants. Among different types of kidney transplantation methods, the present study utilizes kidney transplantation cycles to develop the allocation of unmatched pairs in kidney transplantation using a data-driven optimization technique. In this study, HLA patients were considered as simulated and also a two-objective model in the kidney exchange network was designed to maximize the probability of kidney... 

In this study we developed an analytical model to delve into the behavior of participants in the market of kidney in Iran. We get health as a good which not only elevates the utility of any individual, it add more years to each individual longevity. We find out that ESRD patients who are in serious need of receiving a new kidney will never postpone buying kidney in case of having the price fixed in all periods.We found out that the waiting time in queue of receiving market is a u-shape function in which there is a minimum. We proved that the price making the queue minimum is definitely bigger than the market clearance market. Accordingly, despite all the unfair and immoral view toward... 

The purpose of this study is to model people's behavior on both sides of the kidney market. The healthy person decides to donate a live kidney (for a certain amount) on the supply side. On the demand side, the patient chooses between the two existing kidney queues, the living kidney and the cadaveric kidney, based on the individual's income and belief from the waiting time in each of the two queues. The sick person faces two critical risks in life: risk of death and kidney failure. To model these two risks, it is assumed that each person has a level of health that consists of two deterministic and stochastic parts. In this way, with a deterministic rate, a person's health level will decrease... 

Renal diseases and consequently kidney failure is one of the important death factors around the world in recent years. It causes hundreds of thousands die every year and is in progress. Researchers believe that increasing chemical and nonchemical materials density in the blood which is the air pollution, use of tobacco and other parameters cause renal cells misfunction in urine filtration and regulation of blood pressure. The goal of this work is design and fabrication of a microfluidic device which provides different cell types to be cultured and imposed pressure. To do this, a high throughput microfluidic device is needed to mimic kidney biologically. Having such a device helps to analyze... 

Chronic kidney disease is one of the silent diseases that progresses slowly, often without symptoms, and can eventually lead to kidney loss. Early detection of this disease can help diagnose it and prevent further problems. Urinary creatinine is an effective biomarker for early diagnosis of chronic kidney disease, but methods available in clinics are problematic for people living in disadvantaged areas because of the high cost and the need for 24-hour urine collection. Currently, paper-based microfluidic devices are being developed because they are easy to manufacture, inexpensive, the fluid is permeable by capillary force, and no additional equipment is needed. In this work, to fabricate a... 

Kidney is one of the most complicated organs in terms of functionality and physiology due to its complicated unique vascular structure. Previous investigations have focused on specific characteristics like length and diameter. Most of these methods are based on Image Processing techniques which prevent a comprehensive study in growth and changes of the vascular system. Lindenmyaer system (L-system) is a parallel rewriting system and a type of formal grammar and had been used to create graphs and natural patterns. By absorbing the physiological characteristics of the kidney and integrating them into parametric L-system, a highly dense and accurate vascular system could be generated with few... 

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... 

Physicians use charts that are prepared by experiments on animals or humans to prescribe drug dosage for patients. This method requires much more time by the Ministry of Health to approve new drugs to be used in health-care centers. Furthermore،we have no sight on how a specific drug is going to be diffuse in our body. In order to predict the distribution of a drug or any minerals in the kidney we need to model it. The first step would be modeling the important species that influence the urine concentrating mechanism. Due to the complications in modeling that mechanism especially in the inner medulla zone، we hadn’t solid information regarding that area. It is about half a century that...