Islamic Azad University North Tehran Branch

About: Islamic Azad University North Tehran Branch is a education organization based out in Tehran, Iran. It is known for research contribution in the topics: Adsorption & Catalysis. The organization has 868 authors who have published 968 publications receiving 9987 citations.

Solvent effects on stability and 15N NMR shielding of 5-methylcytosine tautomers : A theoretical approach

Abstract: The structure and energies of the tautomers of 5-methylcytosine in gas phase were predicted using Density Functional Theory (DFT) method. Solvent-induced effects on stability and 15N NMR shielding on the most stable tautomers of 5-methylcytosine were calculated using DFT combined with the polarizable continuum model (PCM) and using the gauge-invariant atomic orbitals (GIAO). In a wide range of solvent dielectrics, the 1-H-oxo-amino form (T6) is predicted as the most stable tautomer and the total electronic energy values of the more stable tautomers in the liquid phase decrease with an increase in the dielectric constant. Direct and indirect solvent effects on 15N NMR shielding of the pyrimidine ring of three dominant tautomers are also calculated. It has been shown that in trivalent nitrogens, the observed solvent-induced shielding variation is more strongly related to the intensity of the solvent reaction field rather than on the change of molecular geometry induced by the solvent.

Cloning and Expression of Influenza H1N1 NS1 Protein in Escherichia Coli BL21

Abstract: Background:Influenza virus is globally pathogenic and it is usually associated with zoonotic respiratory diseases. This virus has caused a number of pandemics with a high mortality rate. The non-structural (NS1) protein of influenza A viruses is a non-essential virulence factor that has multiple accessory functions during viral infection. This protein is highly conservative. It has been shown that this protein has a major role against the immunity responses of the host cells. Objectives:The aim of this study is to produce the recombinant Influenza NS1 protein by the use of bacterial production system in order to evaluate the immunological and structural features of the protein in the following researches. Materials and Methods:The NS1 gene construct has been artificially synthesized; subsequently it has been sub-cloned in to the pQE30 expression vector. Then the expression vector has been transformed in to the BL21 cells and induced by IPTG, afterward the expression has been evaluated by SDS-PAGE and Western Blotting Techniques. Results:The NS1 gene has successfully cloned and transformed in to expression cells, as a result a 23 kDa band has been observed both on SDS-PAGE and nitrocellulose paper after western blotting. Conclusions:Based on the results of this study, it could be concluded that the NS1 gene of Influenza A H1N1 virus (A/Shiraz/14/2010 Strain), could be cloned and the rNS1 protein (recombinant NS1 protein) could be expressed using bacterial protein translation system. Science this protein is a conservative protein among Influenza A viruses could be used as a potent vaccine for prevention of various types of pandemics caused by Influenza A.

Unsupervised Support Vector Machines for Nonlinear Blind Equalization in CO-OFDM

Abstract: A novel blind nonlinear equalization (BNLE) technique based on the iterative re-weighted least square is experimentally demonstrated for single- and multi-channel coherent optical orthogonal frequency-division multiplexing. The adopted BNLE combines, for the first time, a support vector machine-learning cost function with the classical Sato or Godard error functions and maximum likelihood recursive least-squares. At optimum launched optical power, BNLE reduces the fiber nonlinearity penalty by ~1 (16-QAM single-channel at 2000 km) and ~1.7 dB (QPSK multi-channel at 3200 km) compared to a Volterra-based NLE. The proposed BNLE is more effective for multi-channel configuration: 1) it outperforms the “gold-standard” digital-back propagation and 2) for a high number of subcarriers the performance is better due to its capability of tackling inter-subcarrier four-wave mixing.

Nonlinearity mitigation of optical Fast-OFDM signals using a Wiener-Hammerstein electrical equalizer

Abstract: In this paper, the principles of coherent optical Fast-OFDM and the modem design with the employment of a Wiener-Hammerstein equalizer (W-H/E) are described. Afterwards, we test 16QAM Fast-OFDM with W-H/E for up to 3500 km of transmission. Finally, we compare coherent optical Fast-OFDM with conventional CO-OFDM using W-H/E.

A New Fuzzy Algorithm For Improving Quality of Service In Real Time Wireless Sensor Networks

Abstract: A wireless sensor network comprise a large number of cheap sensors as nodes. These sensors used for data collection and transmition to a central node(sink), are distributed in packed formats in an intended wide area of operation. One of the vital issues in these networks, is their energy constraints which directly affects the network life span. In real time wireless sensor networks (RWSN), not only energy constraints but data delivery time has a vital role in network successful operations as well as data validation. In real time programs, quality of service parameters such as delays must be reduced to a minimum . Reduction of packet losses to increase reliability of data deliveries is another issue in these networks. In this article, a new routing algorithm with fuzzy technique for improving quality of service in RWSN, is presented. The main objectives of this technique are two folds. The first is reduction of energy consumption which results in an increase in the network operations life span and the second is to meet a defined end-to-end delay and hence increasing reliability by reducing number of packet losses considerably. By using different fuzzy parameters and if-then rules, each node can make a decision to choose its next step for routing towards destination (sink). Simulation results show that our proposed new protocol considerably reduces energy usage in the network as well as guaranting the quality of service and noticeable improved performance in comparison with SPEED and THVR.