333 research outputs found

    Ultralong-range polyatomic Rydberg molecules formed by a polar perturber

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    The internal electric field of a Rydberg atom electron can bind a polar molecule to form a giant ultralong-range stable polyatomic molecule. Such molecules not only share their properties with Rydberg atoms, they possess huge permanent electric dipole moments and in addition allow for coherent control of the polar molecule orientation. In this work, we include additional Rydberg manifolds which couple to the nearly degenerate set of Rydberg states employed in [S. T. Rittenhouse and H. R. Sadeghpour, Phys. Rev. Lett. 104, 243002 (2010)]. The coupling of a set of (n+3)s(n+3)s Rydberg states with the n(l>2)n(l>2) nearly degenerate Rydberg manifolds in alkali metal atoms leads to pronounced avoided crossings in the Born-Oppenheimer potentials. Ultimately, these avoided crossings enable the formation of the giant polyatomic Rydberg molecules with standard two-photon laser photoassociation techniques.Comment: 7 pages, 4 figure

    Lyotropic Liquid Crystalline Phases for the Formulation of Future Functional Foods

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    The especial features and advanced characteristics of Lyotropic Liquid Crystalline (LLC) phases as potent nano materials for encapsulation and the development of novel delivery systems for nutraceuticals and other bioactive compounds are reviewed. Exemplary, a focus is set on the health benefits of flavonoids and their current restrictions in bioavailability. Accordingly, our visions for application of LLC phases in the engineering of enhanced flavonoid-based food supplements and correlated challenges to over come are highlighted

    Study of Instability Event of Rock Trench in Vanyar Dam Spillway

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    Vanyar dam is located near Tabriz city, North West of Iran. The side channel overflow spillway of this dam is located on the left side of dam body with discharge capacity of 1330 m3/sec. To construct this spillway a soil-rock slope with height of maximum 140m is excavated. After about three years, some surface cracks and slides started to develop. This research tries to study the reasons of these instabilities and some approaches are presented to stabilize the slope. This slope is located on too weathered and crushed igneous rocks and weak sandstones. The field studies indicated that the most important reasons of these instability events were rainfall penetration, weathering, freezing and melting cycles, static and dynamic loading conditions, increase in slope height, tectonic conditions and shotcrete covering. To stabilize the slope meanwhile doing back analysis, many methods evaluated and considering to advantages and disadvantages of each method and available equipment, some approaches such as: adjustment of the slope gradients, improvement of drainage system, construction of retaining structure, vegetation and stabilizing instable parts of rocks are recommended as remedy works in this case

    Stability of Linear Continuous-Time Systems with Stochastically Switching Delays

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    Necessary and sufficient conditions for the stability of linear continuous-time systems with stochastically switching delays are presented in this paper. It is assumed that the delay random paths are piece-wise constant functions of time where a finite number of values may be taken by the delay. The stability is assessed in terms of the second moment of the state vector of the system. The solution operators of individual linear systems with constant de- lays, chosen from the set of all possible delay values, are extended to form new augmented operators. Then for proper formulation of the second moment in continuous time, tensor products of the augmented solution operators are used. Finally the finite-dimensional versions of the stability conditions, that can be obtained using various time discretization techniques, are presented. Some examples are provided that demonstrate how the stability conditions can be used to assess the stability of linear systems with stochastic delay

    Groundwater Lowering in Deep Excavation (Case Study: Foundation Excavation of Shahid Madani Dam)

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    In many big civil constructions, deep excavation is an essential part of project and groundwater control in excavation process is the prominent tasks. In this paper while mentioning the risks of deep excavation, the solutions of underground water control have been explained and different methods of groundwater control in regard to financial conditions, different soil condition and various depths have been investigated. Groundwater control in foundation excavation of Shahid Madani Dam as a case study is presented. Depth of foundation excavation was about 50 meters in tight valley and excavation was performed under groundwater table. This excavation is one of the deepest excavations in Iran and it has some specific problems related to topographical and geotechnical condition in dam site. Finally the proper methods for groundwater control are presented and recommended. Measurements in excavation period and in the middle of dam body construction have shown that this design method had a good performance

    Omental Torsion After Repeated Abdominal Blunt Trauma

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    Omental torsion is caused by the rotation of the greater omentum on its axis which may lead to tissue infarction and necrosis. It is a rare cause of acute abdomen. Signs, symptoms and paraclinical data are not specific. The patients usually undergo laparotomy for acute abdomen of poorly defined origin. High index of suspicious is required for the diagnosis of this entity. The diagnosis is usually confirmed after an explorative laparotomy. We present clinical characteristics and imaging findings of omental torsion in a young man following repeated blunt abdominal trauma

    Experimental Modeling of Flavonoid-Biomembrane Interactions

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    Nonspecific interactions of flavonoids with lipids can alter the membrane's features (e.g., thickness and fluctuations) as well as influence their therapeutic potentials. However, relatively little is known about the details of how flavonoids interact with lipid components. Structure-dependent interactions of a variety of flavonoids with phospholipid monolayers on a mercury (Hg) film electrode were established by rapid cyclic voltammetry (RCV). The data revealed that flavonoids adopting a planar configuration altered the membrane properties more significantly than nonplanar flavonoids. Quercetin, rutin, and tiliroside were selected for follow-up experiments with Langmuir monolayers, Brewster angle microscopy (BAM), and small-angle X-ray scattering (SAXS). Relaxation phenomena in DOPC monolayers and visualization of the surface with BAM revealed a pronounced monolayer stabilization effect with both quercetin and tiliroside, whereas rutin disrupted the monolayer structure rendering the surface entirely smooth. SAXS showed a monotonous membrane thinning for all compounds studied associated with an increase in the mean fluctuations of the membrane. Rutin, quercetin, and tiliroside decreased the bilayer thickness of DOPC by ∼0.45, 0.8, and 1.1 Å at 6 mol %, respectively. In addition to the novelty of using lipid monolayers to systematically characterize the structure-activity relationship (SAR) of a variety of flavonoids, this is the first report investigating the effect of tiliroside with biomimetic membrane models. All the flavonoids studied are believed to be localized in the lipid/water interface region. Both this localization and the membrane perturbations have implications for their therapeutic activity

    Formation of van der Waals molecules in buffer gas cooled magnetic traps

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    We show that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10^12 cm^-3. We explore the spin relaxation of these molecules in buffer gas loaded magnetic traps, and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T^6 thermal dependence of spin change in buffer gas trapped silver (Ag) is accounted for by the formation and spin change of AgHe, thus providing evidence for molecular formation in a buffer gas trap.Comment: 4 pages, 4 figure
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