Sharif Digital Repository

Skin, the largest organ in the body, presents sophisticated functions for maintaining the structural integrity of the entire body. Skin can regulate the temperature of the body, protect the body against microorganisms, have a sensory function, and produce vitamin-D through UV exposure when in direct sunlight.Due to the self-healing property of skin tissue, skin can be repaired by itself. Nevertheless, if extensive skin loss happens, owing to diabetic ulcers or deep burns, skin will not be able to repair the wound by itself. Therefore, it will lose its functions, and the fabrication of a skin equivalent will be necessary. These skin equivalents will cover the wound, regenerate the native... 

In this research, start-up, performance and stability of a A2O system (Anaerobic/ Anoxic/ Oxic) combined with a Moving Bed Bio Reactor (MBBR), using Kaldnes packings, have been investigated in treating synthetic dairy wastewater. Also the effect of influent Chemical Oxygen Demand (COD), Hydroulic Retention Time (HRT) and Ruturn Activated Sludge (RAS) ratio on removing pollutants such as COD, Total Nitrogen and Total Phosphorous have been studied. The experiments have been designed using ‘Design Of Experiments’ software, and at the end the results have been optimized based on desired terms. The performance and capability of the reactor in removing pollutants in 8, 12 and 16 hours of HRT,... 

The membrane bioreactor (MBR) as an alternative method for simultaneous biodegradation and separation of oily water has received more attention, recently. Normally the MBR works at ambient temperature; therefore, the yield of biodegradation recalcitrant components is low. Increasing temperature improves the efficiency of degradation and reduces the amount of produced sludge. In this study the performance of an aerobic thermophilic and mesophilic membrane bioreactor (MBR) for treating oily wastewater has been investigated. In batch conditions (without applying the membrane), a comparison between COD removal in mesophilic and thermophilic conditions was done. In thermophilic conditions COD and... 

Mesoporous silica nanoparticles (MSNP) have attracted lots of attentions because of their particular characteristics. Physical characteristics such as structure, morphology, porosity, and size of these nanoparticles have strong impact on their function and it can be conceived a wide range of applications for them by manipulating these characteristics. In this research, monodispersed MSNPs with a controllable size in the range of 50-130 nm and pore size in the range of 4-24 nm were synthesized and positively functionalized in order to develop a carrier for the delivery of nucleic acids (siRNA and pDNA). The MSNPs were synthesized by the template removing method.In this method, sodium... 

With the rapid development of biotechnology, peptide and protein drugs are now playing an increasingly important role in therapeutics. Compared with chemical drugs, peptide and protein drugs have some limitations such as low stability and rapid deactivation. Biodegradable and biocompatible polymeric micro carriers have been shown to have a high potential for the delivery of peptides and proteins. Among these polymers, alginate has been widely investigated as a biomaterial. Alginates are natural polysaccharide polymers isolated from brown seaweed. Bovine serum albumin (BSA) loaded calcium alginate microspheres produced in this study by a modified w/o emulsification method. The influence of... 

Chlorinated hydrocarbons such as trichloroethylene form a kind of dense non-aqueous phase liquid contaminants in groundwater and soil that are so difficult to remediate. In recent years, many field research has been demonstrated application of nano scale zero valent iron can degrade these contaminants.
In this research, nZVI particle synthesized by liquid phase reduction method. Nickel (25%wt ) has been added to increase the reduction rate and also reduce intermediate pollutions. However, the combination of a noble metal to nZVI, leads to more rapid oxidation and tendency to agglomeration. So nZVI particles coated by applying a water soluble-starch solution (0.4%wt) as a stabilizer. The... 

Cancer is an abnormal growth of cells which is one of the major cause of worldwide’s mortality. Circulating Tumor Cells (CTCs) are rare cancer cells released from the primary or metastatic tumors and transported though the peripheral circulatory system and spreads in body and seize healthy organs. Early detection of CTCs can help in overtaking the cancer, hence isolation of CTCs is an essential step for many therapeutics. In spite of its clinical potential, the isolation and detection of CTCs has been a challenging task due to its rare presence amongst other blood cells (as low as 1–10 CTCs per billions of blood cells), similarity to white blood cell in size and also variability in terms of... 

L-asparaginase enzyme is a well known enzyme due to itschemotherapeutic properties. However, this is not the only feature of the enzyme. L- asparaginase can be also used in food processing to reduce of acrylamide which is a carcinogenic substance. furthermore, acrylamide formation, is prevented by addition of the enzyme before cooking process of some foods such as chips, which contains sugar and asparagine amino acid. Due to use of the enzyme in food industry, we need to produce enzyme with high activity and cheaper raw material. In the present study, Candida utilis ATCC 9950 was used to produce asparaginase enzyme, and beet molasses and yeast extract was used as a carbohydrate and... 

L-Asparaginase has two major uses. For decades it has been known and used as an antitumor agent. Besides, it has been introduced as a food processing aid in the last trench against acrylamide formation in foods. Here, we have produced extracellular L-Asparaginase from Candida utilis and studied the parameters surrounding its production. Thus, two species of yeast were cross-examined: Saccharomyces cerevisiae (BBRC 30006) and Candida utilis (ATCC 9950). Moreover, the most suitable method for detecting and determining L-Asparaginase activity was investigated and selected for this purpose which is via L-Aspartate determination with Hydroxylamine. Furthermore, six deferent parameters of... 

In recent years, many studies have conducted research about stem cells due to their prominent features such as proliferation and differentiation. By changing the specific parameters of the cellular micro-environment, it is possible to determine the stem cells fate and thereby use them in medical affairs. For this purpose, various devices and methods have been designeds such as microfluidic devices and scaffolds. The microfluidic devices has been especially focuced in the researchs due to their unique features, like the possibility of testing with small amounts of samples, the creation and control of low cost cellular micro-environment and low practical time. Two-dimensional scaffolds made up... 

Carbon nitride is a compound that has the proper energy gap (2.7 eV) for activities in the visible light. In this research, photocatalysts based on nanoporous Carbon nitride sheets was synthesized with three primary ingredient (urea, melamine and melamine hydrochloride) by pyrolysis method. Ag, Cu, Fe2O3 and Fe3O4 were added to the system to prevent the electron-hole recombination as well as increscent the photocatalytic activity. The chemical bonding state properties and microstructure of the synthesized photocatalysts were investigated by means of XRD, SEM, BET, FTIR, DRS and PL methods. In the first step of the research, the activity of prepared compounds was analyzed by visible light for... 

In this thesis, photocatalytic oxidation as a potential method for the treatment of organic environmental contaminants is deeply investigated. While the photocatalytic degradation of various organic compounds under UV light irradiation has been widely investigated, visible-light-induced photocatalytic degradation of low-levels of the pollutants such as Dibenzothiophene (DBT) and 2-Nitrophenol (2-NP) are occasionally reported. In the present work, Lanthanide / Polyethylene glycol -modified TiO2 (La/PEG/TiO2) and Fe,Cu,S/TiO2 have been successfully synthesized by a sol–gel method. The photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission... 

Alpha amylase enzyme is one of the most important enzymes used in a wide range of industries. The enzyme is used in industries such as detergents, food, pharmaceuticals, paper making and textile. Various national and international articles have been published on this enzyme that focused on specific targets. Despite the extensive studies carried out in this area inside the country, there is still no industrial production of alpha amylase and other enzymes in our country. In the view of the fundamental problem of the lack of industrialization of these studies, in addition to the lack of a riskier investor, it seems that there is a lack of industrial vision in these studies.In this study, the... 

Beta cells are responsible for secreting insulin to maintain normoglycaemia throughout the individual’s life. Type 1 Diabetes Mellitus (T1DM) is a metabolic disorder characterized by an autoimmune response that promotes the destruction of beta-cells within the pancreatic islets, resulting in lifelong inadequate insulin secretion. Encapsulating beta cells inside a semipermeable membrane to protect encapsulated cells from direct contact with the host immune system, is a new way to treat type 1 diabetes without the need for long-term immunosuppression. . In this case, the semipermeable membrane surrounds the cells and allows oxygen, nutrients, and cell products to penetrate bilaterally while... 

In this thesis periodic plasmonic nanostructures are studied for detection of biological specious. The behavior of metal nanostructure arrays under normal incidence has been widely reported. However, simulation of periodic dispersive structures under oblique incidence requires newer formulations. Formulations, and algorithms based on modified split-field finite-difference time-domain (SF-FDTD) method are introduced, permitting analysis of metallic nanostructures arrays under oblique incidence. These novel algorithms are practically implemented on a parallel processing system based on graphics processing unit (GPU). Test and verification of these formulations are done by analyzing referenced... 

New methods of cancer treatment are always the attention of researchers all over the world, among which the photothermal treatment method is of particular importance. In addition to being easy, this treatment method has the least invasiveness. Studies have shown that combining this method with other methods such as chemotherapy not only can be very effective in destroying tumor tissue, but can significantly reduce the side effects of chemotherapy drugs.In order to apply the photothermal treatment method, an effective photothermal agent is needed. Molybdenum disulfide nanosheets have performed successfully in this field, which have been of great interest, due to their high efficiency in... 

Lipopolysaccharide (LPS), also known as endotoxin, is a highly toxic component exists in the outer membrane of gram negative bacteria. It releases into the environment during every phase of bacterial growth cycle, so it causes contamination of a wide range of biopharmaceutical products. Even small quantities of endotoxin injected to human body can result in fever, septic shock, and death. Therefore, it is highly important to detect and also quantify endotoxin of biopharmaceutical products in quality control laboratories. The most validated method used for endotoxin detection is Limulus Amebocyte Lysate (LAL). Although this method is sensitive, it has some unavoidable drawbacks such as highly... 

The heart diseases and in particular coronary artery disease have been vastly increased in recent years. Bypass operation is the major recognized way of this disease treatment however, one third of patients don’t have the suitable autologous vein for this operation. It should be noted that for this operation a suitable conduit with diameter as narrow as possible is needed. On the other hand, usage of synthetic polymers won’t be suitable for this operation due to the coagulation forming. The only way to overcome this problem is the use of tissue engineering with the aid of scaffold and autologous cells with the natural tissue function, which reconstructed the desire tissue causing no... 

Natural tissues of body consist of Extra Cellular Matrix (ECM) and cells. Scaffold produces a temporary matrix for cells and facilitates oxygen and nutrients transport which enhances tissue regeneration. Therefore, attempts in regeneration of tissues and organs by scaffolds attracted great interest in today’s researchs. Choosing scaffold fabrication method and its polymer type, play a key role in scaffold specifications as they determine scaffold properties. In this project electrospinning was chosen as the scaffold fabrication method which is because of the unique properties of scaffolds fabricated by this method and also its ability in producing micro and nano fibers. At first set of... 

Burns are one of the most important accidents related to human health. Due to the intense physical and mental complications and high fatality rate associated with them, receiving proper treatment is of paramount importance. The control of infection in wounds would cure and eliminates the effect of wounds and treatment of skin lesions with engineered scaffolds can be an effective method. The purpose of this project is proposing a hydrogel scaffold based on natural polymers of oxidized alginate and gelatin loaded with an herbal drug to control infection and treat burn wounds. For this purpose, the Iranian Oak extract that it's main content is Tanin and PolyPhenolinc materials, was prepared and...