Sharif Digital Repository

In this research, Fe3O4 nanoparticles/graphene oxide (Fe3O4/GO) and Fe3O4/polypyrrole/graphene oxide (Fe3O4/PPy/GO) magnetic nanocomposites were fabricated for DNA isolation. The prepared aminated nanocomposite conducted perfect DNA isolation characteristics. The results showed that the Freundlich isotherm and the pseudo-second-order models well-matched the equilibrium extraction data and kinetic outcomes, respectively. The electrophoresis findings confirmed the efficacy of as-prepared nanocomposites for DNA adsorption/desorption. In addition, the adsorption capacity was reduced by 8.9% after five cycles, implying that Fe3O4/PPy/GO nanocomposite can maintain increased isolation ability after... 

In this paper, a novel microfabrication process of a six DOF thermal compliant nanopositioner is presented. The microfabrication process was based on bulk micromachining process. By using this process some important operational restrictions which are usually created by surface micromachining were removed. Moreover, this novel process does not need SOI wafers and needs only ordinary wafers. Therefore, it makes microfabrication process cheaper than surface micromachining processes where SOI wafer should be used. This method is completely appropriate for microactuators which have 120 degree misalignment. Finally, a primary test by using interferometer method was used to test connection of... 

In this paper, a novel microfabrication process of a six DOF thermal compliant nanopositioner is presented. The microfabrication process was based on bulk micromachining process. By using this process some important operational restrictions which are usually created by surface micromachining were removed. Moreover, this novel process does not need SOI wafers and needs only ordinary wafers. Therefore, it makes microfabrication process cheaper than surface micromachining processes where SOI wafer should be used. This method is completely appropriate for microactuators which have 120 degree misalignment. Finally, a primary test by using interferometer method was used to test connection of... 

When a loan is approved for a person or company, the bank is subject to credit risk; the risk that the lender defaults. To mitigate this risk, a bank will require some form of security, which will be collected if the lender defaults. Accounts can be secured by several securities and a security can be used for several accounts. The goal is to fractionally assign the securities to the accounts so as to balance the risk. This situation can be modeled by a bipartite graph. We have a set S of securities and a set A of accounts. Each security has a value vi and each account has an exposure ej. If a security i can be used to secure an account j, we have an edge from i to j. Let fij be the part of... 

Structural systems will normally fail as a consequence of a chain of different components failure es. In this paper, fatigue reliability of fixed offshore platforms is investigated by analyzing different failure scenarios. In order to evaluate the occurrence probability of a special scenario, it is divided into a finite number of sub-scenarios. All combinations of time sequences are generated for a given sequence of failures, using a specially developed program. In order to calculate the occurrence probability of each scenario, a massive reliability analysis should be done for each of corresponding sub-scenarios. A large number of sub-scenarios should be analyzed, therefore implementing time... 

We present a new model universe based on the junction of FRW to flat Lemaitre-Tolman-Bondi (LTB) solutions of Einstein equations along our past light cone, bringing structures within the FRW models. The model is assumed globally to be homogeneous, i.e. the cosmological principle is valid. Local inhomogeneities within the past light cone are modeled as a flat LTB, whereas those outside the light cone are assumed to be smoothed out and represented by a FRW model. The model is singularity free, always FRW far from the observer along the past light cone, gives way to a different luminosity distance relation as for the CDM/FRW models, a negative deceleration parameter near the observer, and... 

Background: Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder caused by mutations in the ataxia telangiectasia mutated (ATM) gene. A-T patients manifest considerable variability in clinical and immunological features, suggesting the presence of genetic modifying factors. A striking heterogeneity has been observed in class switching recombination (CSR) in A-T patients which cannot be explained by the severity of ATM mutations. Methods: To investigate the cause of variable CSR in A-T patients, we applied whole-exome sequencing (WES) in 20 A-T patients consisting of 10 cases with CSR defect (CSR-D) and 10 controls with normal CSR (CSR-N). Comparative analyses on modifier... 

Background: Ataxia-telangiectasia (A-T) is a rare autosomal recessive disorder caused by mutations in the ataxia telangiectasia mutated (ATM) gene. A-T patients manifest considerable variability in clinical and immunological features, suggesting the presence of genetic modifying factors. A striking heterogeneity has been observed in class switching recombination (CSR) in A-T patients which cannot be explained by the severity of ATM mutations. Methods: To investigate the cause of variable CSR in A-T patients, we applied whole-exome sequencing (WES) in 20 A-T patients consisting of 10 cases with CSR defect (CSR-D) and 10 controls with normal CSR (CSR-N). Comparative analyses on modifier... 

As an FDA-approved biopolymer, silk has been contemplated for a wide range of applications based on its unique merits, such as biocompatibility, biodegradability, and piezoelectricity. As silk, in both crystalline structure and amorphous state, exhibits unique physical, mechanical, and biological properties (promoting cell migration, differentiation, growth, and protein-surface interaction), it is fruitful to understand its potential applications. Sensors, actuators, and drug delivery systems are the best in case. As such, the current effort first introduces silk fibroin (SF) and delineates its characteristics. It then explores the extensive use of this biomaterial in tissue engineering... 

Using multiple antennas at the transmit and receive sides of a passive radar brings both the benefits of MIMO radar and passive radar. However one of the obstacles arisen in such configuration is the receive antennas placement in proper positions so that the radar performance is improved. Here we just consider the case of positioning one receiver among multiple illuminators of opportunity. Indeed it is a start for the solution of optimizing the geometry of the multiple receivers in a passive radar  

SbCl3 supported on montmorillonite K-10 is an efficient catalyst for the ring opening of epoxides with aromatic amines under solvent-free conditions and microwave irradiation to give the corresponding b-amino alcohols in high yields with high regioselectivity  

In this paper, we consider an integrated sensing and communication (ISAC) system with wireless power transfer (WPT) where an unmanned aerial vehicle (UAV)-based radar serves a group of energy-limited communication users in addition to its sensing functionality. In this architecture, the radar senses the environment in phase 1 (namely sensing phase) and mean-while, the communications users (nodes) harvest and store the energy from the radar transmit signal. The stored energy is then used for information transmission from the nodes to UAV in phase 2, i.e., uplink phase. Performance of the radar system depends on the transmit signal as well as the receive filter; the energy of the transmit... 

One of the important obstacles in MIMO (Multiple Input Multiple Output) radars is the issue of designing proper transmit signals. Indeed, the capability of signal design is a significant advantage in MIMO radars, through which, the system can achieve much better performance. Many different aspects of this performance improvement have been considered yet, and the transmit signals have been designed to attain such goal, e.g., getting higher SNR or better detector's performance at the receiver. However, an important tool for evaluating the radar's performance is its ambiguity function. In this paper, we consider the problem of transmit signal design, in order to optimize the ambiguity function...