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.

Fuzzy Clustering Based Routing in Wireless Body Area Networks to Increase the Life of Sensor Nodes

Abstract: Body area networks is one of the types of wireless area networks which has been created to optimize utilizing hospital resources and for earlier diagnosis of medical symptoms, and ultimately to reduce the cost of medical care. This network like most of the wireless networks is without infrastructure and the embedded sensor nodes in the body have limited energy. Hence, the early power completion of the wireless nodes based on the transmission of messages in the network can disrupt the entire network. In this study, a fuzzy clustering based routing is presented to overcome the mention challenge. In this method, the sensor nodes are allocated to the nearest cluster, based on their distance from the cluster head node, and exchange information with the cluster-head at the near distances, and the cluster-head node, due to its high initial energy, can transmit data to the remote server. In this study, due to the movement of the person and the position shift in the sensor nodes and the distances between the cluster-head nodes, sensor nodes belonging to the clusters are also updated and placed in their proper cluster and the transmission of sensory messages was done with its nearest cluster- head node. Simulation results show that the proposed method can be better than other existing methods in and equal condition.

Influence of Quantum Effects on Faraday Rotation in Overdense Plasma

Abstract: Here, we study the influence of the quantum effects on the Faraday rotation of the electromagnetic waves passed through a magnetized plasma layer. The phenomena of the Faraday rotation consists in the changing of the direction of the wave polarization plane occurred due to the interaction of the magnetic field with the electromagnetic waves. The Faraday rotation also takes place for the waves anomalously transmitted through the magnetized overdense plasma. The anomalous transmission can be described by the mechanism of the surface wave excitations. In the presence of the magnetic field, the dielectric tensor of the magnetized plasma obtains imaginary elements which lead to the rotation of the components of the electric field. However, specifically for the overdense plasma, the quantum effects can be significant and therefore should not be ignored. Here, we are interested in studying the influence of the quantum effects on the Faraday rotation for the overdense plasma. In this regard, we also study the dispersion relation and obtain quantum corrections affecting the conditions for the anomalous transmission of the waves. We show that the results are reduced to the ordinary ones at the classical limit.

Frequency and expression of mutacin and putative bacteriocin genes in isolated Streptococcus mutans and its antimicrobial activity against gram-positive and gram-negative bacteria

Abstract: Background: Streptococcus mutans in the oral cavities sable to produce mutacin (bacteriocin-like substances) with antibiotic properties . The aim of this study was to investigate the frequency and expression of genes encoding mutacins typeI, II, III and IV and also two of 8 genes in a cluster encoding the putative bacteriocins, the designated bsm 283, bsm 299, bsm 423, bsm 1889c, bsm 1892c, bsm 1896, bsm 1906c and bsm 1914, were also screened by PCR and specific primers for each type of mutacin biosynthesis gene and then mutacin activity against the indicator strains determined. Methods: In this study, dental clinic samples were collocated; Streptococcus mutans was detected using biochemical tests and molecular methods (PCR). Frequency of mutacin biosynthesis genes types I, II, III and IV, bsm299 and bsm1899 were measured by PCR, using specific primers for each type of mutacin biosynthesis gene. Furthermore, the antimicrobial spectra of Streptococcus mutans isolates against other indicators, including Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Salmonella typhi, Pseudomonas, Escherichia coli were evaluated using well diffusion, disk diffusion and the minimal inhibitory concentrations (MICs) methods. Results: Out of 56 samples collected from patients referred to Milad Hospital dental clinic on October 2011 and three private dental clinics on November 2011, 24 strains of Streptococcus mutans produced mutacins. 67.52% of the strains had a wide antimicrobial spectrum and 37.5% of 67.5% had a high frequency of genes with more inhibitory activity against, Staphylococcus epidermidis, Staphylococcus aureus and Enterococcus faecalis respectively that are more related to putative bacteriocins. The expression frequency o f the bsm gene (putative bacteriocins) was higher than that of the characterized mutacins types (I–IV). The lowest dilution rate mutacin was found against Staphylococcus epidermidis (0.0625 unit/mL). Conclusion: These findings suggested that all putative bacteriocins may represent a large repertoire of inhibitory substances produced by Streptococcus mutans. Therefore, the high diversity of mutacin-producing phenotypes, associated with high frequency of expression of the biosynthesis genes screened and wide antimicrobial activity against Staphylococcus epidermidis could be used as safe antimicrobial agents in treatment of superficial infections such as, removing the pimple caused by Staphylococcus epidermidis.