Sharif Digital Repository

As a novel, recyclable nanocatalyst, (Fe3O4)-GOTfOH based Ag nanoparticles doped Starch/PEG-poly (acrylic acid) nanocomposite (Fe3O4@GOTfOH/Ag/St-PEG-AcA) was applied for one-pot synthesis of 2,4,6-triarylpyridine derivatives under water solvent conditions. The prepared nanocomposite was also evaluated in terms of biocompatibility for wound healing. Fe3O4@GOTfOH/Ag/St-PEG-AcA could be easily removed from the mixture of the reaction by an external magnet and recycled without a considerable decrease of activity even after 10 runs. The new nanocatalyst offered better efficiencies than other commercially available sulfonic acid catalysts. In terms of the bioactivity of nanocatalyst, good... 

The magnetic composite hydrogel was fabricated by the graft copolymerization of itaconic acid (IA) onto starch and Alginic acid in the presence graphene sheets (Gr) and Fe3O4 nanoparticles (Fe3O4@Gr-IA/St-Alg) for Guaifenesin (GFN) delivery and wound healing. The Fe3O4@Gr-IA/St-Alg biomaterial is a hydrogel network endowed the material with magnetic property. In addition, GFN not only achieved effectively bound to the magnetic hydrogel, but also released in a controlled manner. The using external magnetic field has significantly positive influence on the drug release rate. To close, these hydrogel drug carriers offer a favorable platform for magnetically targeted drug delivery as well as a... 

In this study, polycaprolactone (PCL) nanoparticles were effectively synthesized as novel drug delivery systems by the electrospray method. Curcumin (Cur) was selected as the model drug with further enhanced stability of its composition with gluten (GLU). The physical-chemical characterization, including FTIR, UV-vis, and thermal analysis of PCL@Cur-GLU nanocapsules, are explored. The in vitro release profiles described by Ritger–Peppas models were also investigated, showing sustained release for 15 h after a burst release within the first five hours. © 2022 by the authors  

Aims: Synthesis of nanocarrier Fe3O4/silica-starch/PNVCL for drug delivery and Fe3O4/GO-starch for antibiotic removal applications Background: In the first part, the new magnetic nanocomposite including Fe3O4 nanoparticles coated with silica, anchored starch nanoparticles, and poly(N-vinylcaprolactam) and then, loaded by acetazolamide. In the second part, magnetic starch nanocomposites were synthesized and modified with graphene oxide. Methods: The drug loading, release and intrinsic cytotoxicity were measured. Also, the potential of Fe3O4/GO-starch as an adsorbent to remove cephalexin antibiotics from aqueous solutions was evaluated. Result: In the first part, the maximum drug adsorption... 

The current coronavirus disease 2019 (COVID-19) outbreak spread rapidly worldwide. Yet, there is no identifiable antiviral treatment, so an effective drug is urgently needed. Preventive strategies and oxygen therapy are the main practical approaches to prevent and treat COVID-19. Clinical trials are in progress for the antiviral and immunomodulation agents that eventually are being developed for COVID-19 treatment. Pharmacological, immunotherapies, natural-based supplements, biologics, and combination therapies interventions have been established. The concept of drug repurposing was re-visited, and many conventional antivirals or immunosuppresses were evaluated for Efficacy against COVID-19... 

Several methods have been developed in the past for analyzing the porosity and other types of well logs for large-scale porous media, such as oil reservoirs, as well as their permeability distributions. We developed a method for analyzing the porosity logs φ(h) (where h is the depth) and similar data that are often nonstationary stochastic series. In this method one first generates a new stationary series based on the original data, and then analyzes the resulting series. It is shown that the series based on the successive increments of the log y(h)=φ(h+δh)-φ(h) is a stationary and Markov process, characterized by a Markov length scale hM. The coefficients of the Kramers-Moyal expansion for... 

Yeh et al. have recently proposed a mutual authentication protocol based on EPC Class-1 Gen.-2 standard. They claim their protocol is secure against adversarial attacks and also provides forward secrecy. In this paper we show that the proposed protocol does not have cited security features properly. A powerful and practical attack is presented on this protocol whereby the whole security of the protocol is broken. Furthermore, Yeh et al.'s protocol does not assure the untraceabilitiy and backwarduntraceabilitiy attributes. We also will propose our revision to safeguard the Yeh et al.'s protocol against cited attacks  

In this paper, we show how time-sharing method may reduce transmission delay in the dynamic index coding scenario. We propose a novel time-shared dynamic index coding transmission scheme that achieves the maximum index coding gain for a complete bi-directional side information graph and formulate a constrained optimization problem to tune the transmission scheme for the minimum transmission delay. A closed-form solution is presented for the special case of two-user. We also use analytical and simulation results to provide graphical intuition for the obtained results  

Dynamic index coding is a practical generalization of conventional index coding that deals with real dynamic traffic streams. We identify the code-constrained capacity region of a dynamic index coding problem with a complete bi-directional side information graph and introduce the performance metric of dynamic index coding gain to measure how dynamic index coding reduces the required data transmissions. A greedy dynamic index coding scheme is proposed that achieves the maximum coding gain almost everywhere in the identified capacity region. Although the greedy scheme attains the maximum coding gain, its selfish nature may unacceptably increase transmission delay. To address this issue, a... 

This paper suggests methods for improving efficiency of a high step up high efficiency converter based on three state commutation cells. A loss analysis has been performed to identify the source of power loss. Based on this analysis, methods are presented to reduce losses in the most power dissipating elements. These methods include replacing some power diodes with large conduction losses with MOSFETs having small on-state resistance. Efficiency improvement up to %1.25 percent is verified in simulation and experimental results  

Locally multipath adaptive routing (LMAR) protocol, classified as a new reactive distance vector routing protocol for MANETs is proposed in this paper. LMAR can find an ad-hoc path without selfish nodes and wormholes using a random search algorithm in polynomial-time. Also when the primary path fails, it discovers an alternative safe path if network graph remains connected after eliminating selfish/malicious nodes. The main feature of LMAR to seek safe route free of selfish and malicious nodes in polynomial time is its searching algorithm and flooding stage that its generated traffic is equiloaded compared to single-path routing protocols but its ability to bypass the attacks is much better... 

von Willebrand factor (VWF) is a naturally collapsed protein that participates in primary haemostasis and coagulation events. The clotting process is triggered by the adsorption and conformational changes of the plasma VWFs localized to the collagen fibres found near the site of injury. We develop coarse-grained models to simulate the adsorption dynamics of VWF flowing near the adhesive collagen fibres at different shear rates and investigate the effect of factors such as interaction and cooperativity of VWFs on the success of adsorption events. The adsorption probability of a flowing VWF confined to the receptor field is enhanced when it encounters an adhered VWF in proximity to the... 

A general regression neural network technique was applied to design optimization of a liquid-liquid coaxial swirl injector. Phase Doppler Anemometry measurements were used to train the neural network. A general regression neural network was employed to predict droplet velocity and Sauter mean diameter at any axial or radial position for the operating range of a liquid-liquid coaxial swirl injector. The results predicted by neural network agreed satisfactorily with the experimental data. A general performance map of the liquid-liquid coaxial swirl (LLCS) injector was generated by converting the predicted result to actual fuel/oxidizer ratios. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA  

Development of Smart Grid and deployment of smart meters in large scale has raised a lot of concerns regarding customers’ privacy. Consequently, several schemes have been proposed to overcome the above mentioned issue. These schemes mainly rely on data aggregation as a method of protecting users’ privacy from the grid operators. However, the main problem with most of these schemes is the fact that they require a large amount of processing power at the meter side. This, together with the fact that smart meters don't usually have a powerful processor, can cause the unavailability of smart meter data at the required time for operators of the grid, and at the same time prevents smart meters from... 

Real-time applications play a significant role in the area of VANET, and are mainly required for these kinds of networks. On the other hand, when the number of messages received by vehicles increases in the network, then the applied computation load becomes extremely high and consequently, delay on the message authentication process significantly increases. This paper is presented with the aim of introducing a novel cooperative message authentication (CMA) scheme for VANET, the main purpose of which is alleviating the computation load on vehicles while verifying messages by using two-part identity-based signature. The scheme enables vehicles to verify only a limited number of the total... 

A general regression neural network technique is applied for design optimization of liquid-liquid coaxial swirl injectors. Phase Doppler Anemometry measurements for velocity and SMD distributions for various Reynolds numbers are used to train the neural network to generate the injector's performance map. Excellent agreement between the predicted values and the measurements is obtained. It is observed that by reducing the number of randomly selected training samples to about one third of the number of prediction points, one may reconstruct the velocity field in the extrapolation regime with an accuracy of 93%. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc.... 

A general regression neural network technique is proposed for design optimization of pressure-swirl injectors. Phase doppler anemometry measurements for velocity distributions are used to train the neural network. An overall optimized value for the width of the probability is determined. The velocity field in the extrapolation regime is reconstructed with an accuracy of 93%. Excellent agreement between the predicted values and the measurements is obtained. The results indicate that the capability of performing designand optimization studies for pressure-swirl injectors with sufficient accuracy exists by applying modest amount of data in conjunction with an overall optimized value for the... 

Hybrid bioactive inorganic-organic carbon-based nanocomposites of reduced graphene oxide (rGO) nanosheets enlarged with multi-walled carbon nanotubes (MWCNTs) were decorated to provide a suitable space forin situgrowth of CoNi2S4and green-synthesized ZnO nanoparticles. The ensuing nanocarrier supplied π-π interactions between the DOX drug and a stabilizing agent derived from leaf extracts on the surface of ZnO nanoparticles and hydrogen bonds; gene delivery of (p)CRISPR was also facilitated by chitosan and alginate renewable macromolecules. Also, these polymers can inhibit the potential interactions between the inorganic parts and cellular membranes to reduce the potential cytotoxicity....