Sharif Digital Repository

Recently, some wound dressings have been designed that are expected to enhance the wound healing process and prevent blood bleeding and infection. Polymeric dressings have attracted attention due to their biocompatibility, biodegradability, lack of toxicity, and non-allergenic nature. There is widespread interest in using silk fibroin (SF) for this purpose because of its unique properties. Given these points, we have designed an injectable antioxidant hydrogel wound dressing based on SF and Polydopamine(PDA) modified ZnO nanoparticles. First, ZnO nanoparticles were doped with Cu and then modified with PDA (ZnCuO@PDA). XRD, FTIR, SEM, and TEM characterizations were carried out to confirm the... 

Aseptic loosening and infection are two major problems of bone implants. Aseptic loosening occurs due to poor cell growth and poor adhesion to the implant surface over time. Bone infection at the implant site occurs mainly by the staphylococcus aureus bacteria. In some cases, infection occurs in the short term and in the early times after implantation, and in some cases, infection occurs in later times. The aim of this study is to synthesize and evaluate antibacterial coatings, while having cell growth-promoting components and cell differentiation to solve bone implant problems simultaneously. Also, the issue of bacterial resistance to antibiotics and their risks in bone implants is another... 

Coronary artery diseaseaffects millions of persons and isone of the leading causes of morbidity and mortality worldwide. Invasive techniques such as coronary artery bypassgrafting are used to alleviate the lesion of arterial occlusion.Unfortunately, restenosis or occlusion of the graftedconduit occurs over a time frame of months to years with a gradual reduction in patency, especially in vein grafts. Theevents leading to intimal hyperplasia (IH) formation involve numerous cellular and molecular components. Variouscellular elements of the vessel wall are involved as are leucocyte–endothelial interactions that trigger the coagulationcascade leading to localized thrombus formation. Subsequent... 

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... 

Present study is designed to determine the effect of manganese content in primitive inverse spinel structure of iron oxide nanoparticles. PEG coated water base ferrofluids of Mnx¬Fe3-xO4 (0<0>1)nanoparticles were prepared by co-precipitation method in presence of nitrogen gas and ultrasonic waves using NaOH as a base for biomedical purposes. The crystallite size and structure of synthesized nanoparticles were studied using atomic absorption spectroscopy (AAS), X-ray diffraction spectrometry (XRD), field emission scanning electron microscopy (FE-SEM) and dynamic light scattering (DLS) methods. Thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) were used to... 

Today, human is facing and struggling with one of the most deadly disease, Cancer. Accordingly, several research studies are aimed to develop new anticancer drugs. Among the prescribed drugs are Paclitaxel. Unfortunately, despite the anticancer activity, paclitaxel has very low water solubility. To solve this problem several alternatives have been proposed by researchers, e.g. using co-solvents of ethanol:Cremophor El®, as is the case in commercial drug, Taxol®. Unfortunately, these co-solvents have some dangerous and sometimes mortal side effects. To reduce its side effects, researchers have proposed using cyclodextrin as a carrier for paclitaxel on the basis that cyclodextrin has a... 

Tissue engineering has the potential to revolutionize our health care system. Conceptually, lost or malfunctioning tissues will be replaced by man-made biological substitutes to restore, maintain, or improve function. Tissue engineering has already shown great promise to contribute to treatments of a myriad of diseases including osteoarthritis, cancer, diabetes, skin burns, cardiovascular conditions and various traumatic injuries. Tissue engineering is a highly multidisciplinary discipline that demands integration of knowledge, tools and skills from biology, chemistry, engineering and medicine. Integrating nano- and microtechnologies into clinically sized implants represents a major... 

Triboelectric nanogenerator (TENG) works based on the accumulation of electrostatic charges produced on the surface of two dissimilar materials while they are brought into physical contact. When the surfaces are separated by a mechanical force, the induced triboelectric charges generate a potential drop, which can lead to generate an electrical current. Since their invention in 2012, TENGs have shown a rapid development in diversity of structure, amount of output power and range of applications, such as self-powered sensors, touch pads, and smart skin. Various kinds of mechanical force can be used for producing electrical energy: human motion, walking, vibration, rotating tire, wind, flowing... 

Statistical studies indicate the fact that in Iran, like many other developing countries, a significant percentage of buildings are made of traditional materials and most of them are adobe buildings especially in rural areas. Furthermore, geological data indicates that Iran is located in alps-Himalayas seismic zone and exposed by destructive earthquakes and adobe buildings suffer the most damages comparing with other type of the structures. According to these explanations, this research deals with adobe buildings behavior and provides solutions for reinforcing them and improving the seismic response of these buildings. These studies include numerical modeling with finite elements methods by... 

In this thesis we consider the problem of distributed computation by many processors.We mainly concentrate on matrix multiplication problem in this thesis because of its importance. A distributed system consists of N worker processors and one master processor. The master processor should distribute the computation between workers and after computation in each of them, collect the results. In this thesis, we are going to mitigate the effect of straggler processors by using coding methods. Straggler processors can cause delays in the computation time.In this thesis, we firstly introduce a method to multiply any number of matrices in each other. The proposed method occurred in one shot without... 

Increased photo catalytic activity of NiO and 〖Co〗_3 O_4 were obtained by Ni〖Co〗_2 O_4 synthesizing and supporting functionalized multiwall carbon nano-tubes via calcinations followed by hydrothermal precipitation. NiO, 〖Co〗_3 O_4 and Ni〖Co〗_2 O_4 were prepared in the same procedure exactly for the subsequent photo catalytic activity to be compared to Ni〖Co〗_2 O_4/MWCNT later on. The photo catalytic degradation of Reactive Red 120 dye as a deazo organic pollutant model was used for experimental photo catalytic performance analysis. The CCD method was applied for experimental designing, modeling, and optimizing the operational parameters of the photo catalytic degradation of RR120 using... 

The main goal of current investigation was partial reduction of Fe2O3 available in Hematite-rich ore to Magnetite by Fludization Bed method. The reductive gas, CO, was produced by incomplete combustion of Acetylene and Airmixed in inappropriate ratio. X-Ray Diffraction and X-Ray Florescence analyses were implemented in order to conducting qualitative analysis of present phases before and after reduction of the ore. Quantitative analysis of the same phases was also conducted by Titration. The latter analysis revealed the precise magnitude of available iron in each of the oxide containing phases. The chemical composition of the reactor gas was also determined before and after reduction... 

Abstract The problem of competetive facility location can be defined as follows: There are a number of customers in the form of points in space, and two players arrange a number of facilities in the form of points in space, given some limitations, respectively. Each customer’s connection to each facility has a cost for the customer and an advantage for the facility, and each customer wants to be connected to at most one of the facilities which has the lowest cost for him. The goal is to find the strategy of placing the facilities and determining the cost which the facility receives from the customer, in such a way that the player’s profit is maximised.In this thesis, we first sought to... 

Zero knowledge proofs allow a person (prover) to convince another person (verifier) that he has performed a specific computation on a secret data correctly, and has obtained a true answer, without having to disclose the secret data. QAP (Quadratic Arithmetic Program) based zkSNARKs (zero knowledge Succinct Non-interactive Argument of Knowledge) are a type of zero knowledge proof. They have several properties that make them attractive in practice, e.g. verifier's work is very easy. So they are used in many areas such as Blockchain and cloud computing. But yet prover's work in QAP based zkSNARKs is heavy, therefore, it may not be possible for a prover with limited processing resource to run... 

Lightweight clients are a type of blockchain users who do not store all the blocks in the blockchain due to limited resources. These users store only a small part of each block and when needed, request transactions from full nodes that store the entire blockchain. These users have no role in block validation and only want to receive transactions related to their addresses with proof of the inclusion in the block from full nodes.Since light clients rely on full nodes for receiving transactions, their privacy against full nodes is important. The current implementation of Bitcoin uses Bloom filters for privacy, but this offers very little privacy to the users.In this thesis, we study the... 

Soil-structure interaction has significant effect on dynamic behavior of the super structure. This effect is usually investigated in two separate parts, i.e., the Kinematic Interaction effect and the Inertial Interaction effect. The first modifies the input ground motion to the foundation as a result of difference in soil and foundation stiffness. The later, i.e., the II effect, introduces the effect of soil flexibility and radiation of waves into the supporting medium on the response of the structure. These effects are usually considered by introducing a replacement oscillator with modified natural period and damping ratio subjected... 

The  aim  of  this  work  is  to  investigate  some  theoretical  models  developed  in  recent years for describing electronic correlation and apply them to some special problems  and  metallicity  and  insulating  behavior  of  one  type  of  paramagnetic  systems. One  of  the  vast‐applied  and  effective  routines  for  investigating  the  strongly  correlated electron systems is Dynamical Mean Field Theory (DMFT). In the first part,  the  equations  of  DMFT  are  solved  on  nearly  real  frequency  axis  with  a  effective and more reliable solver a little parameter γ above the real axis. This approach  appears  fine  structures  that  can’t  be  captured  with  the ...