Ecological study of zooplankton communities in the Persian Gulf Martyrs Lake (Chitgar-Tehran) and the first report of the freshwater jellyfish Craspedacusta sp. (Cnidaria, Limnomedusae) in Iran

This study focused on zooplankton structure, biodiversity, relationship between a biotic parameters and zooplankton variation, and trophy state of the Persian Gulf Martyrs Lake (Chitgar-Tehran). Based on the lake condition, samples were collected by Juday net at the 5 stations between 2013 and 2014. This study identified 36 zooplankton taxa comprised of Arthropoda (6 genus), Protozoa (6 genus), Rotatoria (20 genus), Nematoda (1 genus), Gastrotricha (2 genus) and Oligochaeta (1 genus). Furthermore, the first record of the freshwater jellyfish Craspedacusta sp. in Iran, with size group of 15-20 mm in diameter in September is reported in the Chitgar lake. The Rotatoria abundance average was measured 61 ±18 ind.l-1 in the lake. The Nematoda, Gastrotricha and Oligochaeta taxa were measured the lowest abundance (< 1 ind.l-1 ) in this study. The annual average zooplankton abundance was measured as 72±18 ind.l-1 . The PCA displayed, the Rotatoria Trichocerca sp. and Polyarthera sp. were dominated with high components loading, low variance and high abundance. The CCA showed, there was no correlation between Rotatoria abundance and a biotic parameters. Based on the zooplankton structure and bio-indicator, the lake situation is in the meso-oligotrophic category. Thus, it is might be increased eutrophication trend due to no management and no aquatic control in this ecosystem

Influence of phonons on exciton-photon interaction and photon statistics of a quantum dot

In this paper, we investigate, phonon effects on the optical properties of a spherical quantum dot. For this purpose, we consider the interaction of a spherical quantum dot with classical and quantum fields while the exciton of quantum dot interacts with a solid state reservoir. We show that phonons strongly affect the Rabi oscillations and optical coherence on first picoseconds of dynamics. We consider the quantum statistics of emitted photons by quantum dot and we show that these photons are anti-bunched and obey the sub-Poissonian statistics. In addition, we examine the effects of detuning and interaction of quantum dot with the cavity mode on optical coherence of energy levels. The effects of detuning and interaction of quantum dot with cavity mode on optical coherence of energy levels are compared to the effects of its interaction with classical pulse

Dynamics of threads and polymers in turbulence: power-law distributions and synchronization

We study the behavior of threads and polymers in a turbulent flow. These objects have finite spatial extension, so the flow along them differs slightly. The corresponding drag forces produce a finite average stretching and the thread is stretched most of the time. Nevertheless, the probability of shrinking fluctuations is significant and is known to decay only as a power-law. We show that the exponent of the power law is a universal number independent of the statistics of the flow. For polymers the coil-stretch transition exists: the flow must have a sufficiently large Lyapunov exponent to overcome the elastic resistance and stretch the polymer from the coiled state it takes otherwise. The probability of shrinking from the stretched state above the transition again obeys a power law but with a non-universal exponent. We show that well above the transition the exponent becomes universal and derive the corresponding expression. Furthermore, we demonstrate synchronization: the end-to-end distances of threads or polymers above the transition are synchronized by the flow and become identical. Thus, the transition from Newtonian to non-Newtonian behavior in dilute polymer solutions can be seen as an ordering transition.Comment: 13 pages, version accepted to Journal of Statistical Mechanic

Correlation Between Mucosal IL-6 mRNA Expression Level and Virulence Factors of Helicobacter pylori in Iranian Adult Patients With Chronic Gastritis

Background: Helicobacter pylori infection is associated with gastritis and marked infiltration of the gastric mucosa by several cytokines secreting inflammatory cells that contribute to sustained local inflammation. In this study, we sought to examine IL-6 expression in H. pylori-infected and uninfected gastric mucosa and elucidate the implication in the pathogenesis of H. pylori-associated gastritis in human. Objectives: The current study aimed to determine mucosal IL-6 mRNA expression level and their correlation with virulence factors and the grade of chronic gastritis among H. pylori infected patients with chronic gastritis from Shahrekord, Iran. Patients and Methods: Mucosal IL-6 mRNA levels was measured by real-time PCR using endoscopic biopsies taken from the gastric antrum of 58 subjects infected with H. pylori and 44 uninfected subjects. Presence of vacA and cagA virulence factors was evaluated using PCR. Results: The IL-6 mRNA expression levels were significantly more elevated in H. pylori-positive patients than uninfected individuals and expression of this cytokine was independent from the virulence factors. There was a correlation between IL-6 expression level and the grade of chronic gastritis. Conclusions: Enhanced induction of IL-6 may be involved in the pathogenesis of H. pylon-associated gastritis

Technical efficiency and resources allocation in university hospitals in Tehran, 2009-2012

Background: Assessment of hospitals' performance in achieving its goals is a basic necessity. Measuring the efficiency of hospitals in order to boost resource productivity in healthcare organizations is extremely important. The aim of this study was to measure technical efficiency and determining status of resource allocation in some university hospitals, in Tehran, Iran. Methods: This study was conducted in 2012; the research population consisted of all hospitals affiliated to Iran and Tehran medical sciences universities of. Required data, such as human and capital resources information and also production variables (hospital outputs) were collected from data centers of studied hospitals. Data were analyzed using data envelopment analysis (DEA) method, Deap2,1 software; and the stochastic frontier analysis (SFA) method, Frontier 4,1 software. Results: According to DEA method, average of technical, management (pure) and scale efficiency of the studied hospitals during the study period were calculated 0.87, 0.971, and 0.907, respectively. All kinds of efficiency did not follow a fixed trend over the study time and were constantly changing. In the stochastic frontier's production function analysis, the technical efficiency of the studied industry during the study period was estimated to be 0.389. Conclusion: This study represented hospitals with the highest and lowest efficiency. Reference hospitals (more efficient states) were indicated for the inefficient centers. According to the findings, it was found that in the hospitals that do not operate efficiently, there is a capacity to improve the technical efficiency by removing excess inputs without changes in the level of outputs. However, by the optimal allocation of resources in most studied hospitals, very important economy of scale can be achieved

Prevention, inhibition, and degradation effects of melittin alone and in combination with vancomycin and rifampin against strong biofilm producer strains of methicillin-resistant Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) bacteria are being recognized as true pathogens as they are able to resist methicillin and commonly form biofilms. Recent studies have shown that antimicrobial peptides (AMPs) are promising agents against biofilm-associated bacterial infections. In this study, we aimed to explore the antibiofilm activity of melittin, either alone or in combination with vancomycin and rifampin, against biofilm-producing MRSE strains. Minimum biofilm preventive concentration (MBPC), minimum biofilm inhibition concentration (MBIC), and minimum biofilm eradication concentration (MBEC), as well as fractional biofilm preventive-, inhibitory-, and eradication concentrations (FBPCi, FBICi, and FBECi), were determined for the antimicrobial agents tested. Cytotoxicity and hemolytic activity of melittin at its synergistic concentration were examined on human embryonic kidney cells (HEK-293) and Red Blood Cells (RBCs), respectively. The effect of melittin on the downregulation of biofilm-associated genes was explored using Real-Time PCR. MBPC, MBIC, and MBEC values for melittin were in the range of 0.625–20, 0.625–20, and 10–40 μg/μL, respectively. Melittin showed high synergy (FBPCi, FBICi and FBECi &lt; 0.5). The synergism resulted in a 64–512-fold, 2–16 and 2–8-fold reduction in melittin, rifampicin and vancomycin concentrations, respectively. The synergistic melittin concentration found to be effective did not manifest either cytotoxicity on HEK-293 or hemolytic activity on RBCs. Results showed that melittin downregulated the expression of biofilm-associated icaA, aap, and psm genes in all isolates tested, ranging from 0.04-folds to 2.11-folds for icaA and from 0.05 to 3.76-folds for aap and psm. The preventive and therapeutic indexes of melittin were improved 8-fold when combined with vancomycin and rifampin. Based on these findings, the combination of melittin with conventional antibiotics could be proposed for treating or preventing biofilm-associated MRSE infections

Determination of economic injury level of Lipaphis erysimi (Hemiptera: Aphididae) on canola var. Hayola 401 in Khuzestan

Canola, an oil seed with high contents of oil, is a major farming in Khuzestan province, where there is an increase over its cultivation year by year. One of the canola key pests is mustard aphid (Lipaphis erysimi Kalt.) in this province. However, there was not available information on the economic injury level (EIL) of the pest that is much vital for correct decision making on pest control. Therefore, a study on EIL was conducted through complete randomized block design with 5 replications and 11 treatments (0, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 aphid per central stem of Hayola 401 variety of canola) inside a netted cage. This research was conducted in Behbahan Agricultural Research Station during 2004-2006. The average of seed yield and also the yeild components was analyzed with Duncanâs multiple range tests. The damage of the aphid was estimated by regression equation. The injury level was estimated by Grain threshold method. The results indicated that EIL was 7.53 and 2.49 cm aphid per central stem of canola in Behbahan region in 2004-2005 and 2005-2006, respectively. Economic threshold (ET) was 5.65 and 1.87 cm2 aphid per central stem of canola