Sharif Digital Repository

In recent years, it is expected that the fabrication of multilayer scaffolds and the use of different methodologies in one product can be a new progressing method in skin substitute production. Accordingly, this project aims to fabricate a bilayered composite scaffold with a combination of hydrogel and electrospinning method. We have tried to prepare a scaffold made of oxidized alginate (OAL), gelatin (G), and silk fibroin (SF) without using corrosive solvents and toxic crosslinking agents as a scaffold and drug delivery system. As different biological, chemical, physical, and mechanical factors play a vital role in the healing process, we have characterized the proposed scaffold via DSC,... 

Metal-organic frameworks (MOFs) are a new class of biocompatible nanomaterials with high specific surface area, which provide the possibility of loading various therapeutic agents. Considering the few studies on the use of MOFs in melanoma cancer treatment, the main goal of this research is to investigate the loading and controlling the release of dacarbazine (DTIC) and also the interaction of DTIC and MOF structure in aqueous environments. Based on this, this study was done in three main parts. In the first part, several types of well-known and often used structures in the drug delivery field, including ZIF-8 (based on zinc), MIL-101-NH2(Fe), and MIL-100(Fe) (both based on iron), were... 

Polycaprolactone (PCL) scaffolds and its composites containing bioactive glass particles (45S5) and TiO2 nanostructures with pre-defined and controlled external and internal architecture were prepared via an indirect three-dimensional (3D) printing process. The scaffolds had an interconnected structure with macro- (400-500 μm) and micro- (~25 μm) pores. Bioactivity, mechanical behavior and kinetics of tissue growth in 3D scaffolds were studied. The size effect of biogactive glass particles (6 μm, 250 nm, <100 nm) and morphology of titania nanostructures (spherical, tube, leaf-like, and flower-like particles) were elaborated. The biogactive glass particles with different sizes were prepared... 

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... 

Considering the limitations of fossil fuels in recent years, as well as increasing demand for biofuels, it is anticipated that future attention to biofuels will increase further. Among biofuels, due to some disadvantages of bioethanol and biodiesel fuel, there is a tendency to use biobutanol, which does not have the disadvantages of the mentioned fuels. The cost of chemical production of butanol also led researchers to use biotechnology production of butanol. According to studies, butanol production can be achieved by fermenting some sugars such as glucose, xylose, and ... by anaerobic microorganism, but the cost of using these sugars has resulted in the use of natural sources of these... 

Physical processes such as adsorption and membrane filtration are in progress and considered as efficient methods in separation and treatment of organic pollutants from petrochemical and colored wastewaters. The advantages of these methods include high energy efficiency, low cost, facile process, and regeneration and implementation ability for a wide range of contaminants. Nevertheless,requirement of suitable materials as adsorbents with high adsorption capacity, capability of preparing membranes based on these materials, optimization of process conditions and removal improvement have still remained as the main challenges; therefore, these topics have been mentioned as main aims of this... 

Treatment of critical-size bone defects caused by sport injuries, accidents, trauma, infection, and osteoporosis remains a major clinical challenge. In order to repair or regenerate large bone defects, bioactive three-dimensional scaffolds play a key role due to their multilevel porous structure, high surface area, enhanced mass transport and diffusion. Many studies reported that macropore diameters greater than 500 µm can lead to vascularized bone tissue. In this study, a hierarchically porous composite scaffold was prepared. Hierarchically porous silk fibroin- bioactive glass composite and fibroin scaffold were fabricated with controlled architecture and interconnected structure with... 

Diabetes is one of the most prevalent chronic diseases. Blood glucose control provides diabetics with the opportunity to keep their normal lifestyle, being a productive resource in the society, while ignoring to do so impose a huge cost to the society. Hence, it is of vital importance to find an appropriate approach to control and prevent the subsequent complications of diabetes. One of the most effective approaches is self monitoring of blood glucose (SMBG), which is now available through the commitment of a number of medical equipment companies to introduce SMBG products to the market. Some of the noted companies appointed Iran medical equipment market as a target for their market... 

At major-minor intersections with no timing and signal control, with comparison to those with signal control, a lower level of control is imposed on intersection’s traffic. So the driver’s behavior has more effective and important role on geometric and traffic design of intersection. Therefore, recognizing drivers’ behavior at this kind of intersections seems to be vital. In this research drivers’ behavior in big cities in Iran at major-minor intersections has been studied. For this purpose, 7 major-minor intersections which have stop control at minor approach and median at major approach have been selected and shot. After extraction of primary data from taken digital video films and... 

As petroleum resources are not steadily distributed in the world and all industries and manufacturing sections are dependent on these resources, petroleum transportation is very important to the extent that availability of these resources occurs in the fastest time and costing the least possible. The objective of this study is to study the petroleum distribution through time in the world and assess its transportation efficacy during 1965-2005 in 173 countries. Collecting information about petroleum distribution between exporting countries to importing ones helped to complete the study data base. Also in this study two transportation networks, sea and land multimodal transportation network... 

Considering the extensive developments achieved up to now in the fields of trade and international transportation, as well as the key role of the freight transportation in the economical development of a zone or a country, the present research, titled “A Study of the Trade and Transportation Trends”, was planned. The available data concerning the trade of six types of the goods according to The United Nations Classification (SITC), within the period 1965-2005, have been analyzed in this research. The study has been focused on the Asian Multimodal Network constituted of 31 countries. Trading centre of each country in the selected network is assumed to be located in its capital town. The... 

Although rural inhabitants constitute a large portion of developing countries’ population, they have always been neglected in many ways. Expansion of equity, calls for a new concern in adequacy of rural development. The problem could be considered in two aspects: Firstly, there is a great tendency for immigration to nearby cities, hoping for a better life. This would result in more crowded cities, extended poverty and an increasing rate of crime mainly in suburban areas. On the other hand, the evacuation of farms and fertilized lands imposes great economical loss to the country. Therefore, development of rural facilities should be integrated into national policies to assure a homogeneous and... 

The Study of antecedents and considering the status of Project-Based Organizations (PBOs) in our country such as MSA, Azarab, Sadad Machine, etc indicates that they are facing lots of problems in different aspects. This bad situation is in a way that amendment of part of sections guarantees the continuity of bad performance of these companies and we have to apply Business Process Reengineering and establishing a radical change in these firms. So the present research according to managers and experts opinions, several year observations of the writer and review of the literature of BPR, Project Management (PMBOK) and PBOs; and based on a library research, introduces the processes of PBOs in 3... 

Increasingly adopting of multiple channels by companies in order to achieve greater market coverage and more sale, has made managers to deal with a new challenge of avoiding conflict in multiple channels. The importance of the issue and lack of empirical research provided motivation to study approaches to minimize multiple channel conflict and explore how they reduce conflict. Therefore a qualitative study using a single case (Solico Group) was conducted. After reviewing the literature 7 approaches were identified to minimize multiple channel conflict: Superordinate goals (goals that achieving them requires efforts and resources of more than one channel), Brand (using products with different... 

One of the methods that have been used in order to mitigate the air pollution problem is the IM program in order to identify the high polluting vehicle and make them to adjust their engine in accordance to the emission standards. In Iran due to the air pollution problems the government operates a rudimentary IM program based on the idle engine test utilizing an exhaust gas analyzer which should be done annually. While IM programs usually regarded as a useful tool for soothing the air pollution, one of the criticisms about the program is that it is required for the entire fleet and it reduces the cost effectiveness of the program. This research studies the relationship between the vehicular... 

In today's competitive market we are witnessing the continouse production of new products. This forces companies to choose their branding strategies very carefully، since a wrong decision and a failure can lead to unfortunate consequences. So، Investegiating the factors that can affect new product branding strategies have become very important. Among these strategies, brand extention strategy has been more popular since it can increase the success probability of a new product. As a result، in this research we have investigated the influencers of evaluation of two branding strategies: brand extension and new brand. More specifically، this research aims to investigate the relation between... 

Frontage roads are widely used to separate the main and the local traffic flows in multilane highways. Based on the studies conducted by Texas Transportation Institute, the delay imposed by ramp junction is considered for calculating the average speed in frontage roads in addition to the control delay caused by traffic lights. This delay and the capacity of frontage roads are analysed using gap acceptance theory. In this study, two different sections consisting of a basic section and merge area are selected along Tehran-Karaj special road as case studies and the required data are collected by video recording. After classifying and analysing the data, a wide range of macro traffic-analyses... 

The main factor ensuring safety of passing maneuvers on two lane highways is known as Passing Sight Distance (PSD). The criteria presented in Iran's code and AASHTO Green book are provided by the results of researches conducted between years 1938 & 1941 in the United States. This research intends to find out whether some changes should be applied to the PSD criteria according to current vehicles' performance and driving behavior in Iran. For this purpose, about 8 hours of video films has been recorded from 3 different sites chosen from two-lane highways in Iran, resulted in 326 passing records. In the case of passing of two passenger cars The models provided by analyzing the videos show that... 

Incidents are one of the main sources of delays and they have significant influences on road safety and congestions, air pollution and trip costs. In the time of an incident occurrence, minimizing the response time is essential for several reasons. The most important issue is providing aid for the injured. The faster the persons who are severely injured receive aid, the higher their chances are to be rescued. Also, if the rescue crews get to the incident scene faster the clearance procedure would be accomplished faster and this would result in fewer disturbances in traffic stream and lowering the probability of secondary incidents occurrence. Automatic Incident Detection, AID, has been... 

In this research, the trends of trade and transportation for the 10 subdivisions of food products and food products as a whole product based upon Standard International Trade Classification, SITC, have been appraised during the time period covering 1965 to 2005 among 125 countries in Asia, Europe and Africa. In this respect, the data of trade for the mentioned goods was gathered and other variables including gross domestic product, population, access to the international waters and area of countries and three transportation networks comprising two multimodal transportation networks and a unimodal network, during the cited period and for 125 countries was gathered. Then, regressions of trade...