206 research outputs found

    Feeding habits of yellowfin seabream (Acanthopagrus latus) in the northern region of the Persian Gulf

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    Feeding habits of yellowfin seabream (Acanthopagrus latus) was investigated in coastal waters of the Northern Persian Gulf. This investigation was conducted by monthly sampling of thirty fish from September 2011 through August 2012. Fish size ranged from 17.98 ± 2.07 to 32.31 ± 6.52 cm in total length and from 134.01 ± 45.62 to 720.46 ± 292.58 g in weight. The highest value of gastro-somatic index was obtained in September (5.22 ± 0.04) and the lowest in December (1.61 ± 0.03) with annual average of 2.50 ± 0.60. The result of gastro-somatic index revealed that the highest feeding activity of A. latus was during autumn. The highest level of vacuity index was observed in summer (34.95 ± 4.71) and the lowest in autumn (25.88 ± 2.71) indicating that the highest number of empty stomachs was in summer. Annual average of vacuity index was 30.14 ± 5.72 exhibiting that A. latus was comparatively gluttonous in the Northern Persian Gulf. Bivalves and shrimps were the major food items found in the stomach of A. latus showing food preference indices of 45.86% and 30.67%, respectively. Other food items included crabs (12.66%), aquatic plants (4.05%), animal derivatives (4.52%) and gastropods (2.23%). According to the results, animal derivatives, aquatic plants and gastropods were eaten accidentally and were not the food items of A. latus in coastal waters of Hormozgan. The average relative length of gut was 1.41 ± 0.15 showing that A. latus was omnivorous in this region

    Antiviral effects of Lactobacillus crispatus against HSV-2 in mammalian cell lines

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    Background: Herpes simplex virus type 2 (HSV-2) infectious disease is one of the most common viral sexually transmitted diseases. As regards, vaginal lactobacilli play an important role in protecting host against the urogenital pathogens; here we assessed the potential antiviral activity of Lactobacillus crispatus against HSV-2 infection in vitro. Methods: Both Vero and HeLa cell lines were treated by L. crispatus before, during and after HSV-2 infection. The pre-incubation assay was also performed for the evaluating of virus adsorption by L. crispatus. Virus titer reduction in each stage was determined by a plaque reduction assay. Results: L. crispatus significantly decreased the infectivity of the HSV-2 in initial steps on both cell lines; however, no significant inhibition was ascertained during adsorption and multiplication process. The lactobacilli adhere on Vero cells two-fold stronger than HeLa and subsequently protect the Vero cells nearly 2.5 fold higher than HeLa cell against the virion. Co-incubation of HSV-2 with bacterial cells prior to virus inoculation significantly decreased the virus titer. Conclusion: L. crispatus appears to inhibit the entry of the virus into cells by trapping HSV-2 particles. In addition, formation of L. crispatus microcolonies in the cell surface could block HSV-2 receptors and prevent viral entry to cells in initial infection steps. © 201

    Sandwich structure polymer electrolyte membranes containing phosphotungstic acid immobilized electospun nanofibers

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    The advances in proton exchange membranes (PEM)s is critical for improving the performance of fuel cells [1]. Membranes compromising perfluorosulfonic acid polymers such as Nafion have been used extensively due to their desired conductivity and stability. However, these materials need to be saturated with water to obtain practical level of proton conductivity. There is a strong demand for the PEMs to work at lower relative humidity or under anhydrous conditions because the electrochemical reactions will be accelerated and water management of fuel cell will be simpler. Various designing strategies and advanced materials have been developed to mitigate for this issue without causing serious loss in proton conductivity or stability [2]. Among all, the introducing of inorganic proton conductors such as heteropoly acids have been considered widely. Generally, HPAs (such as phosphotungstic acid H3PW12O40, PWA) have a very strong Brønsted acidity approaching the superacid region (more acidic than Nafion) [3]. In this work, high level of PWA was self-anchored onto nylon electrospun nanofiberous sheet (Figure 1b). Sandwich structured proton conducting membranes were fabricate by assembling nanofibrous central layer with outer Nafion layers (Figure 1b). Since the PWA is attached to the polymer backbones, the risk of leaching out is minimized. Moreover, the significant synthetic versatility of the method helps to increase PWA immobilization level. As shown in the Figure 1c, proton conductivity of as high as 60 mS cm-1 at 30 °C was achieved which is comparable with Nafion 115. The durability of the proton conductivity of sandwiched membrane

    Electronic and optical properties of doped TiO2 by many-body perturbation theory

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    Doping is one of the most common strategies for improving the photocatalytic and solar energy conversion properties of TiO2, hence an accurate theoretical description of the electronic and optical properties of doped TiO2 is of both scientific and practical interest. In this work we use many-body perturbation theory techniques to investigate two typical n-type dopants, niobium and hydrogen, in TiO2 rutile. Using the GW approximation to determine band edges and defect energy levels, and the Bethe-Salpeter equation for the calculation of the absorption spectra, we find that the defect energy levels form nondispersive bands lying 3c2.2 eV above the top of the corresponding valence bands ( 3c0.9 eV below the conduction bands of the pristine material). The defect states are also responsible for the appearance of low-energy absorption peaks that enhance the solar spectrum absorption of rutile. The spatial distributions of the excitonic wave functions associated with these low-energy excitations are very different for the two dopants, suggesting a larger mobility of photoexcited electrons in Nb-TiO2

    Pseudogap phase of cuprate superconductors confined by Fermi surface topology

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    The properties of cuprate high-temperature superconductors are largely shaped by competing phases whose nature is often a mystery. Chiefly among them is the pseudogap phase, which sets in at a doping pp^* that is material-dependent. What determines pp^* is currently an open question. Here we show that the pseudogap cannot open on an electron-like Fermi surface, and can only exist below the doping pFSp_{FS} at which the large Fermi surface goes from hole-like to electron-like, so that pp^* \leq pFSp_{FS}. We derive this result from high-magnetic-field transport measurements in La1.6x_{1.6-x}Nd0.4_{0.4}Srx_xCuO4_4 under pressure, which reveal a large and unexpected shift of pp^* with pressure, driven by a corresponding shift in pFSp_{FS}. This necessary condition for pseudogap formation, imposed by details of the Fermi surface, is a strong constraint for theories of the pseudogap phase. Our finding that pp^* can be tuned with a modest pressure opens a new route for experimental studies of the pseudogap.Comment: 15 pages, 5 figures, 7 supplemental figure

    Adiponectin secretion by perivascular adipose tissue supports impaired vasodilation in a mouse model of accelerated vascular smooth muscle cell and adipose tissue aging

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    Objective: Perivascular adipose tissue (PVAT) function during aging has not been investigated in detail so far and its effect on vasodilation remains to be fully elucidated. The aim of this study was to investigate endothelium-dependent vasodilation of thoracic aorta in a mouse model of accelerated, selective vascular smooth muscle and PVAT aging, induced by SM22α-Cre-driven genetic deletion of the endonuclease ERCC1 (SMC-KO mice) versus healthy littermates (LM). We hypothesized that PVAT enhances vasodilation in LM, possibly through adiponectin secretion, which might be compromised in SMC-KO animals. Methods: Thoracic aorta was isolated from SMC-KO animals and LM and segments with and without PVAT were mounted in wire myography setups. The endothelium-dependent vasodilation was assessed via acetylcholine dose-response curves and pathway contribution was studied. Moreover, adiponectin secretion was measured after stimulating the aortic segments with PVAT with acetylcholine. Results: Adiponectin, secreted by PVAT, led to increased NO-contribution to endothelium-dependent vasodilation in healthy LM, although this did not increase maximum relaxation due to loss of EDH. Endothelium-dependent vasodilation was decreased in SMC-KO animals due to reduced NO-contribution and complete EDH loss. Despite strong lipodystrophy the PVAT partially compensated for lost vasodilation in SMC-KO. LM PVAT contained acetylcholinesterase that attenuated acetylcholine responses. This was lost in SMC-KO. Conclusions: PVAT-derived adiponectin is able to partially compensate for age-related decline in NO-mediated vasodilation, even during strong lipodystrophy, in conditions of absence of compensating EDH. In aorta with healthy PVAT acetylcholinesterase modulates vascular tone, but this is lost during aging, further compensating for decreased acetylcholine responsiveness. Thus, preservation of adiponectin levels, through relatively increased production in lipodystrophic PVAT, and reduction of cholinesterase might be regulatory mechanisms of the PVAT to preserve cholinergic vasodilation during aging.</p

    Adiponectin secretion by perivascular adipose tissue supports impaired vasodilation in a mouse model of accelerated vascular smooth muscle cell and adipose tissue aging

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    Objective: Perivascular adipose tissue (PVAT) function during aging has not been investigated in detail so far and its effect on vasodilation remains to be fully elucidated. The aim of this study was to investigate endothelium-dependent vasodilation of thoracic aorta in a mouse model of accelerated, selective vascular smooth muscle and PVAT aging, induced by SM22α-Cre-driven genetic deletion of the endonuclease ERCC1 (SMC-KO mice) versus healthy littermates (LM). We hypothesized that PVAT enhances vasodilation in LM, possibly through adiponectin secretion, which might be compromised in SMC-KO animals. Methods: Thoracic aorta was isolated from SMC-KO animals and LM and segments with and without PVAT were mounted in wire myography setups. The endothelium-dependent vasodilation was assessed via acetylcholine dose-response curves and pathway contribution was studied. Moreover, adiponectin secretion was measured after stimulating the aortic segments with PVAT with acetylcholine. Results: Adiponectin, secreted by PVAT, led to increased NO-contribution to endothelium-dependent vasodilation in healthy LM, although this did not increase maximum relaxation due to loss of EDH. Endothelium-dependent vasodilation was decreased in SMC-KO animals due to reduced NO-contribution and complete EDH loss. Despite strong lipodystrophy the PVAT partially compensated for lost vasodilation in SMC-KO. LM PVAT contained acetylcholinesterase that attenuated acetylcholine responses. This was lost in SMC-KO. Conclusions: PVAT-derived adiponectin is able to partially compensate for age-related decline in NO-mediated vasodilation, even during strong lipodystrophy, in conditions of absence of compensating EDH. In aorta with healthy PVAT acetylcholinesterase modulates vascular tone, but this is lost during aging, further compensating for decreased acetylcholine responsiveness. Thus, preservation of adiponectin levels, through relatively increased production in lipodystrophic PVAT, and reduction of cholinesterase might be regulatory mechanisms of the PVAT to preserve cholinergic vasodilation during aging.</p

    Phosphoric acid functionalized graphene oxide: a highly dispersible carbon-based nanocatalyst for the green synthesis of bio-active pyrazoles

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    Carbon-based catalysts are gained significant interest for improving a number of catalytic processes due to their unique set of benefits. However, a few of such catalysts are proper for synthesis of organic compounds in water. Therefore, there is a strong need for developing water-tolerant and dispersible catalysts. Here, we demonstrate a simple and efficient method for the preparation of highly dispersible phosphonic acid functionalized carbocatalyst. The applied functionalization method was flexible in controlling the functionalization level. The prepared nanocatalyst exhibited superior catalytic performance toward multicomponent synthesis of pyrano[2,3-c]pyrazole, with 80-90% yield within 15 min in water. Moreover, this water-tolerant solid acid. catalyst could be simply retrieved and after 6 successive cycles of reactions, the reaction time and yield still keeps within the same level

    Drug-related mutational patterns in hepatitis B virus (HBV) reverse transcriptase proteins from Iranian treatment-Naïve chronic HBV patients

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    Background: Immunomodulators and Nucleotide analogues have been used globally for the dealing of chronic hepatitis B virus (HBV) infection. However, the development of drug resistance is a major limitation to their long-term effectiveness. Objectives: The aim of this study was to characterize the hepatitis B virus reverse transcriptase (RT) protein variations among Iranian chronic HBV carriers who did not receive any antiviral treatments. Materials and Methods: Hepatitis B virus partial RT genes from 325 chronic in active carrier patients were amplified and directly sequenced. Nucleotide/amino acid substitutions were identified compared to the sequences obtained from the database. Results: All strains belonging to genotype D.365 amino-acid substitutions were found. Mutations related to lamivudine, adefovir, telbivudine, and entecavir occurred in (YMDD) 4% (n = 13), (SVQ) 17.23% (n = 56), (M204I/V + L180M) 2.45% (n = 8) and (M204I) 2.76% (n = 9) of patients, respectively. Conclusions: RT mutants do occur naturally and could be found in HBV carriers who have never received antiviral therapy. However, mutations related to drug resistance in Iranian treatment-naïve chronic HBV patients were found to be higher than other studies published formerly. Chronic HBV patients should be monitored closely prior the commencement of therapy to achieve the best regimen option. © 2013, KOWSAR Corp
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