596 research outputs found

    Dynamical Systems on Hilbert C*-Modules

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    We investigate the generalized derivations and show that every generalized derivation on a simple Hilbert C∗C^*-module either is closable or has a dense range. We also describe dynamical systems on a full Hilbert C∗C^*-module M{\mathcal M} over a C∗C^*-algebra A{\mathcal A} as a one-parameter group of unitaries on M{\mathcal M} and prove that if α:R→U(M)\alpha: \R\to U({\mathcal M}) is a dynamical system, where U(M)U({\mathcal M}) denotes the set of all unitary operator on M{\mathcal M}, then we can correspond a C∗C^*-dynamical system α′\alpha^{'} on A{\mathcal A} such that if δ\delta and dd are the infinitesimal generators of α\alpha and α′\alpha^{'} respectively, then δ\delta is a dd-derivation.Comment: 7 pages, minor changes, to appear in Bull. Iranian Math. So

    Comparative study of the vibrational optical activity techniques in structure elucidation : the case of galantamine

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    The absolute configuration of the alkaloid galantamine was studied using a range of solution-state techniques; nuclear magnetic resonance (NMR), vibrational circular dichroism (VCD), and Raman optical activity (ROA). While the combined use of NMR and VCD does provide a fast, high-resolution methodology for determining the absolute configuration of galantamine, both techniques were needed in concert to achieve this goal. ROA, on the other hand, proved to be sensitive enough to assign the full absolute configuration without relying on other techniques. In both cases, statistical validation was applied to aid the determination of absolute configuration. In the case of galantamine, ROA combined with statistical validation is shown to be a powerful stand-alone tool for absolute configuration determination

    Biological assessment of the Tang Sorkh River (Iran) using benthic macroinvertebrates

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    A biological assessment of the Tang Sorkh River (Iran) was studied from July 2013 to August 2014 using benthic macroinvertebrate communities. Samples were gathered every two months, from five stations using a Surber sampler( 30×30cm), fixed in formalin (4%) and then separated and identified in the laboratory. Environmental conditions (current velocity, temperature, depth, width, dissolve oxygen, conductivity, pH, alkalinity, Total Suspended Solids (TSS) and grain size) were measured. In addition, diversity and biotic indices were used to determine the water quality of the river. Results showed that 5 classes, 9 orders and 20 families were identified in this river. The families Hydropsychidae (Trichoptera), Simuliidae (Diptera) and Baetidae (Ephemeroptera) were dominant. Shannon-wiener and Simpson indices showed the highest diversity at station 1 and the lowest diversity in station 4. According to the Hilsenhoff, ASPT and BMWP indices, station 1 had good water quality for aquaculture

    Effect of Anionic Polymers on Drug Loading and Release from Clindamycin Phosphate Solid Lipid Nanoparticles

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    Purpose: To develop and characterize solid lipid nanoparticle (SLN) systems containing dextran sulfate or sodium alginate as anionic polymers for the delivery of clindamycin phosphate as a model hydrophilic cationic drug.Methods: A multi-level factorial design was used for the preparation and optimization of clindamycin SLNs. Polymers (dextran sulfate and sodium alginate), Tween 80, and Pluronic F68 were chosen as the independent variables. The SLNs were prepared using stearic acid as the lipid matrix by an emulsion congealing technique with cold homogenization. Particle size and drug loading were evaluated as the primary responses. The morphology and drug release rate of the selected formulations were also determined.Results: The results revealed that incorporation of anionic polymers increased drug loading of theSLNs. Dextran sulfate had a greater effect on drug loading, increasing it from 1.32 to 18.19 %, compared to the 6.73 % achieved using sodium alginate. Dextran sulfate also reduced drug release rate by half compared with sodium alginate, probably due to the higher charge density, lower molecular weight and lower branching density of the ionic polymer.Conclusion: Incorporation of anionic polymers can increase the loading of clindamycin phosphate into SLNs. Drug release from SLNs is also dependent on the polymer type.Keywords: Clindamycin, Solid lipid nanoparticles, Dextran sulfate, Sodium alginate, Anionic polymers, Drug release, Drug loadin

    Virtual water highway: water use efficiency in global food trade

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    International audienceAmid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the regional, national and global water budget has received much attention in recent years. Built upon the knowledge of virtual water accounting in the literature, this study examines the efficiency of the resource use embodied in the global virtual water trade from the perspectives of exporting and importing countries. Different characteristics between "green" and "blue" virtual water corresponding to rainfed and irrigated agriculture are elaborated. The investigation reveals that the virtual water flows primarily from countries of high water productivity to countries of low water productivity, generating a global saving of water resources. Meanwhile, the domination of green virtual water in the total virtual water trade constitutes low opportunity costs and environmental impacts as opposed to blue virtual water. The results suggest efficiency gains in the global food trade in terms of water resource utilization. The study raises awareness of negative impacts of increasing reliance on irrigation for food production in many countries, including food exporting countries. The findings of the study call for a greater emphasis on rainfed agriculture to improve global food security and environmental sustainability

    The Anatomical Position of Appendix in Iranian Cadavers

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    Background: Vermiform appendix is different in terms of anatomical position, length and mesoappendix.  Knowing the anatomical position of vermiform appendix is important for the surgeons in terms of diagnosis and management. The aim of this study is analysis of length, anatomical position and mesoappendix of vermiform appendix.Methods: This is a cross-sectional study on the 400 randomly selected cadavers (306 male and 94 female) who have been referred to the autopsy hall of legal medicine organization of Tehran province to be autopsied between March 21, 2010 and March, 2011. The cause of death was very heterogeneous among autopsied cadavers.Results:According to our results the anatomical positions were pelvic, subcecal, retroileal, retrocaecal, ectopic and preileal in 55.8%, 19%, 12.5%, 7%, 4.2% and 1.5% respectively. The mean length of vermiform appendix was 91.2 mm and 80.3 mm in men and women, respectively. Mesoappendix was complete in 79.5% and incomplete in 20.5%. No association was seen between sex and anatomical position of vermiform appendix.Conclusion:Anterior anatomical position was the most frequent vermiform appendix position in our population which is in discrepancy with most of the reports from western countries. It might be possible that factors such as race, geographical regions and nutritional regiment play roles in determining the position of vermiform appendix

    Analyses of impacts of China's international trade on its water resources and uses

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    This study provides an insight into the impact of China's international trade of goods and services on its water resources and uses. Virtual water flows associated with China's international trade are quantified in an input-output framework. The analysis is scaled down to the sectoral and provincial levels to trace the origins and destinations of virtual water flows associated with the international trade. The results show that China is a net virtual water exporter of 4.8 × 10<sup>10</sup> m<sup>3</sup> yr<sup>−1</sup>, accounting for 2.1% of its renewable water resources and 8.6% of the total water use. Water scarce regions tend to have higher percentages of virtual water export relative to their water resources and water uses. In the water scarce Huang-Huai-Hai region, the net virtual water export accounts for 8.0% of the region's water resources and 11.3% of its water uses. For individual sectors, major net virtual water exporters are those where agriculture provides raw materials in the initial process of the production chain. The results suggest that China's economic gains from being a world "manufacture factory" have come at a high cost to its water resources
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