Accessory gene regulator types of Staphylococcus aureus isolated in Gorgan, North of Iran

Background: Staphylococcus aureus is a gram-positive bacterium that has remained a persistent pathogen, causing infections such as endocarditis, meningitis, and toxic shock syndrome in humans. The accessory gene regulator (agr) system of Staphylococcus aureus is responsible for controlling the expression of many genes that code for virulence factors. In this study, we assessed the S.aureus agr Group, based on their source of isolation, in Gorgan, North of Iran. Materials and Methods: DNA of 194 S. aureus isolates was extracted by lysozyme-phenol chloroform method, which included 85 clinical samples, 58 samples which were isolated from noses of health care workers and 51 cases which were obtained from food products in Gorgan, northern Iran. PCR-based assays were used to evaluate agr locus nucleotide polymorphism for the identification of agr specificity Group. Distributions of each agr Group were determined and comparison between different sources was assessed by X2. A p-value of <0.05 was considered as significant. Results: The majority of isolates belonged to agr Group I (43.3%), followed by agr Group III (28.87%), agr Group II (22.68%), and agr Group IV (5.15%). In our study, a majority of S. aureus isolates were recovered from health care workers and food product specimens were of agr Group I and isolates which were recovered from patients were of agr Group III. These differences were statistically significant (P=0.005). There was no statistical difference between the source of isolation of clinical samples of S.aureus and agr type. Conclusion: Agr Group I was predominant among health care workers and food product specimens in Gorgan, North of Iran, but in strains which were isolated from patients, agr Group III was predominant. Investigating the possible role of agr Group III in Staphylococcus aureus infection in future studies is recommended

Higher angular momentum Kondo liquids

Conventional heavy Fermi liquid phases of Kondo lattices involve the formation of a "Kondo singlet" between the local moments and the conduction electrons. This Kondo singlet is usually taken to be in an internal s-wave angular momentum state. Here we explore the possibility of phases where the Kondo singlet has internal angular momentum that is d-wave. Such states are readily accessed in a slave boson mean field formulation, and are energetically favorable when the Kondo interaction is between a local moment and an electron at a nearest neighbor site. The properties of the d-wave Kondo liquid are studied. Effective mass and quasiparticle residue show large angle dependence on the Fermi surface. Remarkably in certain cases, the quasiparticle residue goes to zero at isolated points (in two dimensions) on the Fermi surface. The excitations at these points then include a free fractionalized spinon. We also point out the possibility of quantum Hall phenomena in two dimensional Kondo {\em insulators}, if the Kondo singlet has complex internal angular momentum. We suggest that such d-wave Kondo pairing may provide a useful route to thinking about correlated Fermi liquids with strong anisotropy along the Fermi surface.Comment: 12 pages, 7 figure

Analysis of Receptor’s Distribution in Entorhinal Cortex after Induction of Spreading Depression in Juvenile Rats

Spreading depression (SD), discovered by Leao in 1944, is a pathophysiological wave which propagates slowly in the brain (3 mm/min) and cause dramatic ionic and hemodynamic changes. SD appears to act through several mechanisms and receptors which have not completely understood. Here, we studied the effect of inhibitory system in animal model of SD using immunohistochemistry technique. After implanting recording electrodes and cannula over the brain, repetitive SD was induced by KCl injection (2 M) in juvenile rats for four consecutive weeks. Then all rats were decapitated and the brains removed. Mean number of dark neurons in entorhinal cortex were determined using Toluidine blue staining. To identify the prevalence and distribution of γ-aminobutyric acid A (GABA-A) subunit receptors and glutamic acid decarboxylase (GAD), immunohistochemistry technique was performed. The mean number of SD induced by KCl injection was statistically increased during four weeks of experiments (P=0.036). The mean number of dark neurons in entorhinal cortex was significantly increased in SD group compared to sham rats (P≤0.001). Also, expression of GAD 65 receptor in the Entorhinal cortex significantly increased in SD group compare to control group (P<0.05). GABA-Aα and GABA-Aβ receptors didn’t show significant change in that region. These data suggest that SD is able to damage neural cells and also it could lead to enhancement of GAD, the enzyme which is responsible for synthesizing an important inhibitory neurotransmitter, GABA receptor, in the central nervous system. Keywords: Cortical Spreading Depression, Entorhinal Cortex, Gamma-Aminobutyric Acid

Rotation Rate of Particle Pairs in Homogeneous Isotropic Turbulence

Understanding the dynamics of particles in turbulent flow is important in many environmental and industrial applications. In this paper, the statistics of particle pair orientation is numerically studied in homogeneous isotropic turbulent flow, with Taylor microscale Reynolds number of 300. It is shown that the Kolmogorov scaling fails to predict the observed probability density functions (PDFs) of the pair rotation rate and the higher order moments accurately. Therefore, a multifractal formalism is derived in order to include the intermittent behavior that is neglected in the Kolmogorov picture. The PDFs of finding the pairs at a given angular velocity for small relative separations reveals extreme events with stretched tails and high kurtosis values. Additionally, The PDFs are found to be less intermittent and follow a complementary error function distribution for larger separations.Comment: 16 pages, 3 figures, accepted for publication in European Journal of Mechanics / B Fluid

Possible role of TORCH agents in congenital malformations in Gorgan, northern Islamic Republic of Iran

This descriptive, cross-sectional study was carried out to explore the frequency of contamination with TORCH agents in neonates with congenital malformations in a referral centre in Gorgan city, Islamic Republic of Iran. Blood samples were taken from 64 neonates and their mothers over a 20-month period in 2003-04. Serologic tests showed that 4/64 infants born with congenital malformations (6%) had positive IgM antibody titres for Toxoplasma gondii (2 cases), rubella virus (1 case) and cytomegalovirus (1 case). IgM was positive in 9/63 mothers (14%), also for T. gondii (3 cases), rubella virus (3 cases) and cytomegalovirus (3 cases). No cases of herpes simplex virus type II or Treponema pallidum were found