Sharif Digital Repository

I-131 isotope is one of the most significant radio medicines for treatments of the thyroid cancer and nuclear tomography of thyroid. As for purification of this radioisotope several methods have been developed among which adsorption-desorption on metallic copper is the most promising. The current study is aimed at elaboration of the kinetics behavior of the different types of metallic copper for adsorption of iodine vapor. The used copper samples included plain and silica-supported Cu nanoparticles as well as micronized copper. The silica-supported Cu nanoparticles were prepared by impregnation of highly porous silica (≈500 m2/g) in Cu(NO3)2 solution, heating of the solution to above... 

We have reported a new and efficient synthesis of tetrahydrothiopyrano [2,3-b]indole skeletons via unique tandem reaction of indoline-2-thiones to Baylis-Hillman adduct acetates. This protocol is a very mild and simple method for construction heterocycles in a one-step process. This is a convenient and diastereoselective synthesis of methyl 4-aryl-2,3,4,9-tetrahydrothiopyrano[2,3-b]indole-3-carboxylate systems in the presence of K2CO3 in acetonitrile. The major benefits of the current study are the one-pot procedure, high yields and diastereoselectivity, short reaction times and the similarity of the products to the biologically active moieties.
In addition 1, 4-diazabicyclo [2.2.2]... 

Growth of the fuel consumption in the world and the greenhouse effect of its pollution get industrial managers and environmental activities attention. Skin drag force has a significant role in energy uses. The drag reduction property of superhydrophobic surfaces shows a new approach for investigators to reduce energy uses. Surface with 150° contact angle called superhydrophobic surface.In this project, a superhydrophobic coating is developed based on acrylic hydroxyl resin by silica nanoparticles. This coating can be sprayed on any surface. Using the Iron oxid particles and silica nanoparticles together produces hierarchical micro-nano structures. This coating has a 160.1° contact angle on... 

This research aims to develop a drug delivery system based on mesoporous silica nanoparticles (MSNPs) for hydrophobic drugs and evaluating their cytotoxicity. The internal environment of the body is aqueous, while most of effective drugs display poor aqueous solubility, resulting in insufficient bioavailability. Due to their several unique properties, such as a large surface area, tunable pore size, facile surface multi functionalization and excellent biocompatibility, MSNPs are recognized as promising and powerful tools to overcome this hurdle. In the present study, MSNPs were synthesized using template removing method and then were functionalized through grafting procedure. They were... 

Nowadays, self-healing process, repairing minor damages automatically without the need for detection or any type of manual intervention, becomes a hot topic of general interest. In this research, the effect of addition of carbon nanocontainers doped with film forming epoxy and polyamine agents in various contents on the self-healing properties of epoxy resin was investigated. Carbon nanocontainers were synthesized via the silica templating method and carbonization of polysaccharide shells at the high temperature. Loading of the film forming agents into carbon nanocontainers was performed using vacuum jar method in the presence of epoxy/acetone and polyamine/acetone dilute solutions.... 

In this research UHMWPE/FUMED SILICA nanocomposites with different concentrations of nano fumed silica (0.5, 1.5, 2.5, 4.5 wt %) were prepared via in situ polymerization using a novel Bi-supported Ziegler-Natta catalytic systems. Magnesium etoxide and Fumed Silica functionalized by hydroxyl groups were used as supports of catalyst. TiCl4 accompanied by triethylaluminum constituted Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were done in slurry phase under the argon atmosphere. Scanning Electron Microscopy (SEM) images also certified very good dispersion of fumed silica throughout PE matrix. Intrinsic viscosity measurements showed high molecular weight for... 

Epoxy resins have good mechanical and thermal properties, high chemical resistance and low shrinkage during cure but in spite of these good properties,they are brittle and this limits the usage of them. Adding a second, soft or rigid, phase has been always an effective strategy to improve the toughness of epoxy. Rigid phase used in resins are divided into organic and inorganic. The aim of this study is to increase epoxy toughness, maintaining mechanical properties and study effect of silica and polycarbonate on fracture toughness simultaneously. Mechanical properties including yield strength and elastic modulus are evaluated by pressure test. Additionally fracture toughness and three... 

The main object of this thesis is production and investigation of polypropylene-fumed silica nanocomposites by using bi-supported Ziegler-natta catalytic system and in-situ polymerization. Magnesium ethoxide and fumed silica were used as supports of catalyst. TiCl4 was accompanied by triisobutyl aluminum(TiBA) and diisobutyl phthalate(DIBP) as electron doner constituting Ziegler-Natta catalytic system. Preparation of catalyst and polymerization were taken place in slurry phase under the argon atmosphere. At the beginning of the polymerization experiment, several type of nanocomposites were made under various conditions(such as different Al/Ti molar ratio) to find optimum condition to... 

This thesis is a research corresponding to Super-Hydrophobic condensation substrates with Nanometer texture. In this study, the foresaid surfaces are fabricated by two methods that are Nano-composite paint and Electrophoretic coating. As a summary for the first method (the Super-Hydrophobic Nano-composite paint), the hybrid coating contains two mineral and organic phases; The organic phase is a two-part clear-coat polyurethane and plays the role as a polymer matrix in Nano-composite structure. Silica Nano-particles are the mineral phase and the two phases of Nano-composite have made connection with silane compounds. Also, surface-modification in Nano-particles for giving hydrophobicity... 

Blending can be used as one of the ways of producing materials with appropriate properties, which have many relative advantages in comparison with other methods like polymerization. Among the existing blends in the market and scientific areas, blends of polyurethane thermoplastic and polypropylene have been also studied because of its commercial importance and scientific interest. This blending can improve the mechanical properties, friction resistance, improvement of impact strength at low temperatures and improvement of plasticity properties. In this research, blends with different ratios of TPU/PP is produced by melt mixing, and for improving properties of blends, two kinds of nano fumed ... 

Rehabilitation usually involves physical therapy, occupational therapy and counseling for the patient's morale to help to restore his power and performance. Considering the economic outlook and the costs of rehabilitation methods and due to the increasing prevalence of stroke and the need to recover the patients in a short period, only the use of robotic systems opens the door to the medical community. Since a large rehabilitation robots designed and built and each been used according to their advantages and shortcomings. In this project, the major shortcomings examined and exoskeleton designed on two major features including portability and covering shoulder workspace. Shoulder movement was... 

In this study, thermal and rheological properties of nanofluids of water/carbon nanotubes, water/spherical silica nanoparticles and water/hybrid nanoparticles (hybrid of carbon nanotubes and spherical silica nanoparticles) have been investigated. To do so, carbon nanotubes have been synthesized by CCVD process and spherical silica nanoparticles and hybrid nanoparticles by wet chemical method. After synthesis of nanomaterials, nanofluids have been prepared by using SDBS as a dispersant with the concentration of 1.5 times of concentration of nanomaterials and then thermal conductivity, kinematic viscosity, dynamic viscosity and density of nanofluids have been investigated. As the results show,... 

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... 

The aim of this work is fabrication of magnetite@silica@gold particles. Study of the effect of pH showed that increasing pH from 9 to 12 resulted in a decrease in the size of magnetite nanoparticles from 7.9±1.38 nm to 5±0.64 nm. The TEM results indicated that modifying magnetic nanoparticles with sodium citrate prior to coating with silica leads to a narrow particle size distribution (275±16.1nm) and less number of silica nanoparticles without any magnetite core. Three methods were applied for attachment of gold nanoparticles seeds onto the silica surface: 1) use of an electrostatic interaction between positively-charged aminated silica and negatively-charged gold nanoparticles surfaces, 2)... 

Today, medical science has come to the conclusion that the best time to start treating a disease is in its early stages. Therefore, the topic of early detection has been widely welcomed in scientific circles. Today, one of the safest methods for early detection in medicine is the study of biomarkers. These biomarkers include CTC, cfRNA, cfDNA, Exosome, etc. For instance, in the discussion of early cancer detection, the US Food and Drug Administration has so far identified two biomarkers, cfDNA and CTC, as the safest markers. The cfDNA marker is also widely used not only in the diagnosis of cancer, but also in the field of sex diagnosis and fetal Down syndrome in the first weeks of pregnancy.... 

The aim of this study was to develop a method to determine the trace residual amounts of nonsteroidal anti-inflammatory drugs in meat-related samples and to study the effect of different cooking methods and storage conditions of meat before cooking as an effective factor on the fate of these drugs. To proceed this goal, a nanocomposite was prepared from polycaprolactone nanofiber/silica mesopores as green sorbent by electrospinning. The synthesized nanocomposite was implemented for micro-solid phase extraction of the desired drugs in conjunction with high performance liquid chromatography. Polycaprolactone, due to its excellent physical properties, availability, biodegradability,... 

Considering the advantages of heterogeneous catalysts for the easy work up procedure, being eco-friendly, and the reusability, herein, two projects are carried out by metal-supported SBA-15 catalysts. The first one is the oxidative deprotection of trimethylsilyl ethers catalyzed Cr (VI) in the presence of TBHP as oxidant. In this project, trimethylsylil ethers are oxidized in good to high yields. The second project is the oxidative coupling of thiols to disulfides catalyzed by Fe (III) in the presence of hydrogenperoxide. This catalyst/oxidant system convets different aromatic thiols to corresponding disulfides efficiently  

Several studies based on anti- cancer, anti- metastatic and anti- tumor effects of curcumin have been reported . Besides these benefits, the therapeutic efficacy of curcumin is limited due to its poor aqueous solubility, extensive first-pass metabolism, inadequate tissue absorption and degradation at alkaline pH, which severely diminishes its bioavailability. In this project we seek to solve some of the problems with nanoscience to work more effectively. In the past decade, mesoporous silica nanoparticles (MSNs) have found widespread application as controlled drug delivery systems. Recent reports on the design of capped and gated MSN-based systems have shown promise in preventing premature... 

By employing the image theory the Er doped microsphere coupled to an external cavity made by a metallic mirror is simulated by a bimicrosphere laser. The symmetric structure causes the formation of odd and even modes corresponding to the TE and TM mode of the microsphere and splitting the oscillation frequencies. The oscillation frequencies are dependent on the coupling coefficient. The coupling coefficient is obtained near the mirror-microsphere distance. The ohmic mirror loss also is determined as a function of the mirror distance. The total optical loss experienced in these resonators is exceptionally low. In fact,quality factor as high as 108 − 1011 have already been demonstrated for... 

In this research, a review on fluoride adsorption revealed that the modification of the adsorber surface with ions like Ca2+ results in great enhancement of the fluoride adsorption. It seems that the enhancement in fluoride adsorption by the modified adsorber, is mainly due to the selective chemical binding of the fluoride ion with the surface-bound ion (Ca2+), regardless of the base material itself. In order to confirm this hypothesis, two different adsorber materials namely, γ-alumina (a material, conventionally used for fluoride removal from water and wastewater) and Micro-silica (a mineral with small adsorption capacity for fluoride) were selected for further study. It was found that the...